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A  SUPPLEMENT 


TO 


URE'S  DICTIONARY 


OP 


ARTS,  MANUFACTURES,  AND  MINES, 


CONTAINING 


A  CLEAR  EXPOSITION  OF  THEIR  PRINCIPLES  AND  PRACTICE. 


FROM  THE  LAST  EDITION, 


EDITED  BY  EGBERT  HUNT,  F.E.S.,  F.S.S., 

Keeper  of  Mining  Records, 
Formerly  Professor  of  Physics,  Government  School  of  Mines,  &c.,  &c., 


ASSISTED     BY   NUMEROUS    CONTRIBUTORS   EMINENT   IN   SCIENCE   AND    FAMILIAR   "WITH 

MANUFACTURES. 


ILLUSTRATED  WITH  SEVEN  HUNDRED  ENGEAVIlTGS  ON  TVOOD. 


NEW  YORK: 
APPLETON    AND     COMPANY, 

443   AND   445  BROADWAY. 
1864. 


This  Yoliime  of  lire's 

2 

Dictionary  of  Arts,  Manufactures,  and 

Mines,  contains  tiie  additional  knowledge  wliicli  has  accumulated 

within  the  past  ten  years. 

]^ot  a 

year  has  passed  but  that  some 

important  improvements  in  the  Arts  and  Sciences  have  taken  place, 

all  of  which   form  an   important 

increase    to   knowledge,  which 

cannot  well  be  dispensed 

with  by 

those  who  are  engaged  in  the 

various  pursuits  in  which 

they  are 

employed. 

The  following  are  a  few,  among  the  many,  who  are  specially 

interested,  viz. : 

Artisans, 

Gunsmiths, 

Assayers, 

Gas  Light  Companies, 

Brewers, 

Glass  Makers, 

Bakers, 

Hat  Makers, 

Boiler  Makers, 

Iron  Mongers, 

Brass  Founders, 

India  Rubber  Manufacturers, 

Bleachers, 

Ink  Manufacturers, 

Brick  Makers, 

Leather  Dealers, 

Button  Manufacturers, 

Miners, 

Chemists, 

Manufacturers, 

Coal  Dealers, 

Plumbers, 

Calico  Printers, 

Paper  Manufacturers, 

Candle  Makers, 

Photographers, 

Confectioners, 

Painters, 

Coppersmiths, 

Perfumers, 

Cotton  Factories, 

Pyrotechnists, 

Carriage  Makers, 

Eope  Makers, 

Distillers,            * 

Sliipping  Merchants, 

Dyers, 

Sugar  Refiners, 

Druggists, 

Silversmiths, 

Engineers, 

Soap  Makers, 

Farmers, 

Tanners, 

Furriers, 

• 

Tobacconists, 

Founders, 

Weavers, 

Gold  Beaters, 

TVine  Growers, 

(fee, 

&c. 

,                &c. 

PREFACE. 


Ure's  Dictionary  of  Arts,  Manufactures,  and  Mines  has  long  had  the 
reputation  of  a  standard  authority  upon  the  subjects  of  which  it  treats. 
But  such  is  the  inventive  activity  of  the  age,  and  the  rapid  improvement 
in  art  processes,  that  a  work  of  this  kind  can  only  maintain  its  character 
by  frequent  and  extensive  additions.  While  the  distinguished  author 
was  in  the  vigor  of  his  intellect,  the  revisions  of  the  work  kept  pace  with 
the  progress  of  improvement,  but  at  his  demise  it  was  found  necessary  to 
organize  a  plan  for  bringing  up  the  Dictionary  to  the  present  state  of 
knowledge.  Accordingly,  Mr.  Robert  Hunt,  a  gentleman  whose  high 
scientific  position  gave  warrant  that  the  work  would  be  well  performed, 
assumed  the  editorship,  and  a  corps  of  the  ablest  practical  and  scientific 
men  in  England  was  secured  to  prepare  articles  in  their  several  depart- 
ments. The  following  remarks,  condensed  from  the  prefoce  to  the  Eng- 
lish edition,  will  explain  the  purpose  and  plan  of  the  editor. 

"  The  objects  which  have  been  steadily  kept  in  view  are  the  follow- 
ino- :  To  furnish  a  work  of  reference  on  all  points  connected  with  the  sub- 
jects included  in  its  design,  which  should  be  of  the  most  reliable  character. 
To  give  to  the  scientific  student  and  the  pubhc  the  most  exact  details 
of  those  manufactures  which  involve  the  application  of  the  discoveries 
of  either  physics  or  chemistry.  To  include  so  much  of  science  as  may 
render  the  philosophy  of  manufactures  at  once  intelligible,  and  enable 
the  technical  man  to  appreciate  the  value  of  abstruse  research. 

"  I  commenced  the  new  edition  of  Ure's  Dictionary  with  an  earnest 
determination  to  render  the  work  as  complete  and  as  correct  as  it  was 
possible  for  me  to  make  it.  In  my  necessities  I  have  asked  the  aid  ^  of 
the  manufacturer,  and  the  advice  of  the  man  of  science,  and  never  having 
been  refused  the  aid  solicited,  I  am  led  to  hope  that  those  who  may  pos- 
sess these  volumes  will  find  in  them  more  practical  knowledge  than  ex- 
ists in  any  work  of  a  similar  character." 

This  volume  of  Ure's  Dictionary  contains  the  chief  additions  made 
to  the  late  English  edition.  Those  portions  of  the  work  which  concerned 
mainly  the  English,  their  commercial  and  manufacturing  resources  and 
statistics,  the  least  important  historic  notices,  and  some  definitions  in 
pure  science,  which  seemed  hardly  embraced  within  the  defined  scope  of 
the  work,  have  been  omitted.  By  this  means  the  original  and  valuable 
contributions  to  the  work  have  been  brought  within  the  limits  of  a  single 


4  PEEFACE. 

volume,  which  has  lost  nothing  of  its  real  value.  This  supplementary 
volume  is  rich  with  the  latest  results  of  inquiry,  containing  all  the  new 
and  important  matter  and  illustrations  of  the  three  English  volumes 
costmg  §38,  while  the  complete  American  edition  of  the  work,  in  three 
volumes,  comprising  3212  pages,  with  2300  engravings,  forms  the  com- 
jDletest  repertory  of  arts,  manufactures,  and  mines,  Avhich  has  been  yet 
published. 

Subjoined  is  a  list  of  the  contributors,  whose  initials  will  be  found 
appended  to  their  respective  articles.  Mr.  Hunt  avows  the  authorship 
of  the  rest. 


G.  ANSELL,  Esq.,  Rojal  Mint. 

H.  K.  liAMBER,  Esq.,"  F.C.S.,  &c. 

[E.  W.  BINNEY,  Esq.,  F.G.S.,  &c.,  Manchester. 

H.  W.  BONE,  Esq.     Euameller, 

HENRY  W.  BRISTOW,  Esq.,  F.G.S.  Geo- 
logical Survey  of  Great  Britain. 

R.  J.  COURTNEY,  Esq.  Superintendent  of 
Messrs.  Spottiswoode  and  Co.'s  Printing  office. 

JAMES  DAFFORNE,  Esq.  Assistant  Editor 
of  the  Art  Journal. 

JOHN   DARLINGTON,  Esq.     Mining  Engi- 
neer.    Author  of  Miner'd  Handbook. 
F.  W.  FAIRHOLT,  Esq.,  F.R.A.S.      Author 

of  Costume  in  England,  Dictionary  of  Terms 
in  Art,  &c. 

E.  FRANKLAND,  Esq.,  Ph.D.,  F.R.S.,  and 

C.S.  Professor  of  Chemistry  at  St.  Bartholo- 
mew's Hospital,  and  Lecturer  on  Chemistry  at 
the  Royal  Indian  Military  College,  Addiscombe. 
ALFRED  FRY'ER,  Esq.  Sugar  Refiner,  Man- 
chester. 

(TJie  late)  T.  H.  HENRY%  Esq.,  F.R.S.  and 

C.S. 
R.  HERRING,  Esq.     Author  of  History  of 

Paper  Manufacture. 

JAMES  HIGGINS,  Esq.     Calico  Printer,  <fcc., 

Manchester. 
W.  HERAPATH,  Esq.,  M.D.,  &c. 
SAMUEL  HOCKING,  Esq.,  C.E.,  Seville. 
RICHARD  W.  HUNT,  Esq.     Brewer,  Leeds. 
T.  B.  JORDAN,  Esq.     Engineer,  Inventor  of 

Wood  Carving  Machinery. 
WILLIAM  LINTON,  Esq.     Artist,  Author  of 

Ancient  and  Modern  Colors. 

JAMES  McADAM,  Jun.,  Esq.     Secretary  of 

the  Royal  Society  for  the  Cultivation  of  Flax 

in  Ireland 
{Tlie  late)  HERBERT  MACK  WORTH,  Esq., 

C  E.,  F.G.S.    One  of  H.  M.  Inspectors  of  Coal 

Miners. 
HENRY  MARLES,  Esq..  L.R.C.P.     Author 

of  English  Grammar,  Currying  and  Leather. 

DAVID  MORRIS.  Esq.,  of  Manchester.  Au- 
thor of  Cottonopolis,  itc. 

JAMES  NAPIER,  Esq..  F.C.S.  Author  of 
Mamual  of  Dyeing.  Electro- Metallurgy,  An- 
cient Workfi  in  Metal,  &c. 

D.  NAPIKR,  Esq.,  C.E.,  &c. 

A.  NORMANDY,  Esq.,  M.D.,  F  C.S.  Author 
of  Handbook  of  Commercial  Chemistry. 

HENRY  M.  NOAD,  Esq.,  Ph.D.,  F.R.S.  Au- 
thor of  .4  Manual  of  Electricity,  &c. 

AUGST.  n.  NORTIIOOTE,  E.sq.  F.C.S.  As- 
hibtant  Clieniist,  University  of  O.\ford. 


ROBERT  OXLAND,  Esq.,  F.C.S.    One  of  the 

Authors  of  Metals  and  their  Alloys. 

THOMAS  JOHN  PEARSALL,  Esq.,    F.C.S. 

Secretary  to  London  Mechanics'  Institntion. 
SEPTIMUS  PIESSE,  Esq.    Author  of  Treatise 

on  Art  of  Perfumery,  &c. 
JOHN  ARTHUR  PHILLIPS,  Esq.    Graduate 

of  the  Imperial  School  of  Mines,  Paris,  Author 

of  Manual  of  Metallurgy. 

ANDREW  CROMBIE  RAMSAY,  Esq.,  F.R.S. 
and  G.S.,  Professor  of  Geolosy,  Government 
School  of  Mines.  Local  Director  of  the  Geologi- 
cal Sur*-ey  of  Great  Britain. 

EBENEZER  ROGERS,  C.E.,  F.G.S.  Late 
President  of  the  South  Wales  Institute  of  En- 
gineers. 

CHARLES  SANDERSON,  Esq.,  Sheffield. 
Author  of  Papers  on  Ste«l  and  Iron. 

E.  SCHUNCK,  Esq.,  Ph.D.,  F.R.S.,  and  C.S. 

R.  ANGUS  SMITH,  Esq.,  Ph.D.,  F.R.S.     An- 

thor  of  various  Papers  on  Air  and  Water,  Life 
of  Dalton,  and  History  of  Atomic  Theory,  &c. 

WARINGTON  W.  SMYTH,  Esq.,  M.A.,  F.R.S. 
and  G.  S  Professor  of  Mining  and  Mineralogy, 
Government  School  of  Mines,  and  Inspector 
of  Crown  Mines. 

THOMAS  SOPWITH,  Esq.,  C.E.,  F.R.S.,  and 

G.S.   Author  oi Isoinetricul  Drauing,  &.c. 

ROBERT  DUNDAS  THOMSON,  Esq.,  M.D., 
F.R.S.  Professor  of  Chemistry  in  St.  Thomas's 
Hospital  College. 

ALFRED  TYLOR,  Esq.,  F.G.S.  Author  of 
Treatise  on  Metal  Work. 

A.  VOELCKER,  Esq.,  Ph.D.,  F.C.S.  Profes- 
sor of  Chemistry,  Agricultural  College,  Ciren- 
cester, and  Consulting  Chemist  to  the  Royal 
Agricultural  Society  of  Englaad. 

CHARLES  V.  WALKER,  Esq.,  F.R.S, 
F.R.A.S.  Engineer  of  Telegraphs  and  Time  to 
the  South  Eastern  Railway  Company,  Author 
of  Elfctrotyjie  Manipu/atiori,  Translator  of 
Kamtz'  Meteorology,  De  la  Rite's  Electricity, 
&c. 

C.  GREVILLE  WILLIAMS,  Esq.  Author  of 
A  Uandbook  of  Chemical  Manipulation,  &c. 

{The  late)  HENRY  M.  WITT,  Esq.,  F.C.S. 
Assistant  Chemist,  Government  School  of 
Mines. 

With  special  assistance  and  information  from 
the  late  Sir  Wni.  Reid,  C.B.,  Governor  of 
Malta  ;  Sir  Wm.  Armstrong,  C.E.,  Ac.  ; 
Robert  Mallet,  Esq.,  C.E.,  F  R.S.,  &c.  ; 
Captain  Drayson,  Royal  Artillery  ;  George 
W.  Lenox,  Esq. ;  and  many  others- 


SUPPLEMENT 


DICTIONARY  OF  ARTS,  MANUFACTURES,  AND  MINES. 


ABA.     A  woollen  stuff  manufactured  in  Turkey. 

ABACA.  A  species  of  fibre  obtained  in  the  Philippine  Islands  in  abundance.  Some 
authorities  refer  those  fibres  to  the  palm-tree  known  as  the  Abaca,  or  Anisa  tcxtilis.  There 
seem,  indeed,  several  well-known  varieties  of  fibre  under  this  name,  some  so  fine  that  they 
are  used  in  the  most  delicate  and  costly  textures,  mixed  with  fibres  of  the  pine-apple,  form- 
ing Pina  muslins  and  textures  equal  to  the  best  muslins  of  Bengal.  Of  the  coarser  fibres, 
mats,  cordage,  and  sail-cloth  are  made.  M.  Duchesne  states,  that  the  well-known  fibrous 
manufactures  of  Manilla  have  led  to  the  manufacture  of  the  fibres  themselves,  at  Paris,  into 
many  articles  of  furniture  and  dress.  Their  brilliancy  and  strength  give  remarkable  fitness 
for  bonnets,  tapestry,  carpets,  network,  hammocks,  &c.  The  only  riftinufactured  articles 
exported  from  the  Philippine  Islands,  enumerated  by  Thomas  de  Comyn,  Madrid,  1820 
(transl.  by  Walton),  besides  a  few  tanned  buffalo  hides  and  skins,  are  8,000  to  12,000  pieces 
of  light  sail-cloth,  and  200,000  lbs.  of  assorted  abaca  cordage. 

ABIES  {in  Botany)^  the  fir,  a  genus  of  trees  which  belong  to  the  coniferous  tribe.  These 
trees  are  well  known  from  their  ornamental  character,  and  for  the  valuable  timber  which  they 
produce.     They  yield  several  resins  or  gum  resins,  which  are  useful  in  the  arts. 

ABIES  BALSAMEA  (the  Balm  of  Gilead  fir)  produces  the  Canadian  balsam.  This  tree 
grows  most  abundantly  in  the  colder  regions  of  North  America. 

ABIES  CANADENSIS  (the  hemlock  spruce  fir).  A  considerable  quantity  of  the  es- 
sence of  spruce  is  extracted  from  the  shoots  of  this  tree  ;  it  is,  however,  also  obtained  from 
other  varieties  of  the  spruce  fir. 

ABIES  PICE  A  of  Linnaeus  {Abies  pedhiata  of  De  Candole).  The  Silver  fir,  producing 
the  Burgundy  pitch  and  the  Strasburg  turpentine. 

ABLETTE,  or  ABLE,  is  a  name  given  to  several  species  of  fish,  but  particularly  to  the 
Bleak,  the  scales  of  which  are  employed  for  making  the  pearl  essence  which  is  used  in  the 
manufacture  of  artificial  pearls.     See  Pearls,  Artificial. 

ABRASION.  The  figuration  of  materials  by  wearing  down  the  surface.  See  File, 
vol.  i. 

ACACIA.  (L.  acacia,  a  thorn ;  Gr.  a.K^,  a  point.)  The  acacia  is  a  very  extensive 
genus  of  trees  or  shrubby  plants,  inhabiting  the  tropical  regions  generally,  but  extending  in 
some  few  instances  into  tlie  temperate  zone ;  being  found,  for  example,  in  Australia,  and 
the  neighboring  islands.  Botanists  are  acquainted  with  nearly  300  species  of  the  acacia ; 
some  of  these  yield  the  c/um  arable  and  the  gum  catechu  of  commerce  ;  while  the  bark  of 
others  yields  a  large  quantity  of  tannin,  especially  a  variety  which  grows  in  Van  Dicmen's 
Land,  or  Tasmania.     See  Arabic,  Gum  ;  Catechu. 

ACACIA  ARABICA.  An  inhabitant  of  Arabia,  the  East  Indies,  and  Abyssinia.  One 
of  the  plants  yielding  the  gum  arable,  which  is  procured  by  wounding  the  bark  of  the  tree, 
after  which  the  sap  tlows  out  and  hardens  in  transparent  lumps. 

ACACIA  CATECHU.  The  catechu  acacia  (Mimosa  catechu  of  Linnffus)  is  a  tree  with  a 
moderately  high  and  st6ut  stem,  growing  in  mountainous  places  in  Bengal  and  Coromandel, 
and  in  other  parts  of  Asia.  Its  unripe  pods  and  wood,  by  decoction,  yield  the  catechu  or 
terra  Japoiiica  of  the  .shops. 

ACESCENT.  Substances  which  have  a  tendency  to  pass  into  an  acid  state  ;  as  an  infu- 
sion of  malt,  &c. 


6  ACETAL. 

ACETAL.  (C"  H"  0*.)  One  of  the  products  of  the  oxidation  of  alcohol  under  the  in- 
fluence of  the  oxygen  condensed  in  platina  blacl<.  It  is  a  colorless,  mobile,  ethereal  liquid 
boiling  at  221°  F.  Its  density  in  the  fluid  state  is  0-821  at  72'.  The  specific  gravity  of  its 
vapor  4"138  Stas.  (mean  of  three  experiments) :  calculation  gives  4-083  for  four  volumes 
of  vapor. — For  the  description  of  the  modes  of  determining  vapor  volume,  consult  some 
standard  chemical  work.  — The  recent  researches  of  Wurtz  render  it  evident  that  the  con- 
stitution of  acetal  is  quite  different  to  what  has  generally  been  supposed,  and  that  it  is  in 
fact  glycodiethyline  ;  that  is  to  say,  glycole  in  which  two  equivalents  of  hydrogen  are  re- 
placed by  two  equivalents  of  ethyle. — C.  G.  \V. 

ACETATE.  {Aa'iate,  Fr.  ;  Esdgsaure,  Germ.)  Any  salient  compound  in  which  the 
acid  constituent  is  acetic  acid.  All  acetates  are  soluble  in  water:  the  least  soluble  being 
the  acetates  of  tungsten,  molybdenum,  silver,  and  mercury.  The  acetates,  especially  those 
of  lead  and  alumina,  are  of  great  importance  to  the  arts.  The  acetates  are  all  described  un- 
der their  respective  bases ; — a  rule  which  will  be  adopted  with  all  the  acids. 

ACETIC  ACID.  {Acide  acitique,  Fr.  ;  Esdgsaurc,  Germ.  ;  Acidum  aceticion,  Lat.  ; 
Eiael,  Sax.)  The  word  "acetic"  is  derived  from  the  Latin  acetuin,  applied  to  vinegar; 
probably  the  earliest  known  body  possessing  the  sour  taste  and  other  properties  which 
characterize  acids  ;  hence  the  term  Acid,  now  become  generic  ;  both  the  Latin  word,  and 
also  the  Saxon  acid  being  from  the  root  acies  (Greek  ok^),  an  edge  or  point,  in  reference  to 
the  sharpness  of  the  taste. 

Acetic  acid  is  produced  either  by  the  oxidation,  or  the  destructive  distillation,  of  organic 
bodies  containing  its  elements — carbon,  hydrogen,  and  ox3-gen. 

The  oxidation  of  organic  bodies,  in  order  to  convert  them  into  acetic  acid,  may  be 
effected  either  : — 1,  by  exposing  them  in  a  finely  divided  state  to  the  action  of  air  or  oxygen 
gas  ;  2,  by  submitting  them  to  the  action  of  ferments,  in  the  presence  of  a  free  supply  of 
atmospheric  air ;  or,  3,  by  the  action  of  chemical  oxidizing  agents. 

When  acetic  acid  is  procured  by  the  oxidation  of  organic  bodies,  it  is  generally  alcohol 
that  is  employed ;  but  by  whatever  process  alcohol  is  transformed  into  acetic  acid,  it  is 
always  first  converted  into  an  intermediate  compound,  aldehyde  ;  and  this  being  a  very  vola- 
tile body,  it  is  desirable  always  to  efiect  the  oxidation  as  completely  and  rapidly  as  possible, 
to  avoid  the  loss  of  alcohol  by  the  evaporation  of  this  aldehyde. 

*  Alcohol  contains    C*  H"  0* 

Aldehyde       "         C^  W  0"" 
Acetic  acid    "         C*  H*  0* 

The  process,  therefore,  consists  first  in  the  removal  of  two  equivalents  of  hydrogen  from 
alcohol,  which  are  converted  into  water, — aldehyde  being  produced, — and  then  the  further 
union  of  this  aldehyde  with  two  equivalents  of  oxygen  to  convert  it  into  acetic  acid.  See 
Aldehyde. 

By  the  oxidation  of  alcohol,  pure  acetic  acid  is  obtained  :  but  the  vinegars  of  commerce 
are  mixtures  of  the  pure  acetic  acid  with  water ;  with  saccharine,  gummy,  and  coloring  mat- 
ters ;  with  certain  ethers  (especially  the  acetic  ether),  upon  which  their  agreeable  aromatic 
flavor  depends  ;  with  empyreumatic  oils,  &c. 

The  pure  acetic  acid  (free  from  water  and  other  impurities)  may  be  obtained  most  ad- 
vantageously, according  to  Mclsens*,  by  distilling  pure  acetate  of  potash  with  an  excess  of 
acetic  acid  (which  has  been  obtained  by  the  redistillation  of  ordinary  acetic  acid,  procured 
either  by  oxidizing  alcohol,  or  by  the  destructive  distillation  of  wood) :  the  acid  which  first 
passes  over  contains  water ;  but  finally  it  is  obtained  free. 

Properties  of  pure  Acetic  Acid. — When  absolutely  pure,  acetic  acid  is  a  colorless  liquid 
of  specific  gravity  1-064,  which  at  temperatures  below  C2'  F.  (17°  C.)  solidifies  into  a  color- 
le.'vs  crystalline  mass.  It  has  strongly  acid  properties,  being  as  powerfully  corrosive  as  many 
mineral  acids,  causing  vesication  when  applied  to  the  skin  ;  and  it  possesses  a  peculiarly 
pungent,  though  not  a  dLsagreeable  smell. 

The  vapor  of  the  boiling  acid  is  highly  combustible,  and  bums  with  a  blue  flame.  Hy- 
drated  acetic  acid  dissolves  camphor,  gliadine,  resins,  the  fibrine  of  blood,  and  several  or- 
ganic compounds.  When  its  vapor  is  conducted  through  a  slightly  ignited  porcelain  tube, 
it  is  converted  entirely  into  carbonic  acid  and  acetone,  an  atom  of  the  acid  being  resolved 
into  an  atom  of  each  of  the  resultants.  At  a  white  heat  the  acid  vapor  is  converted  into 
carbonic  acid,  carburetted  hydrogen,  and  water. 

It  attracts  water  with  great  avidity,  mixing  with  it  in  all  proportions.  Its  solution  in 
water  increases  in  density  with  the  increase  of  acetic  acid  up  to  a  certain  point ;  but  beyond 
this  point  its  density  again  diminishes.  Its  maximum  density  being"l-073,  and  correspond- 
ing to  an  acid  containing  C^  H'  0*  -f-  2Aq.,  which  may  be  extemporaneously  produced  by 
mixing  77-2  parts  of  crytallized  acetic  acid  with  22-8  parts  of  water.  This  hydrate  boils  at 
104°  C.  (219°  F.),  whilst  the  crystallized  acid  boils  only  at  120°  C.  (248°  F.)f 

*  Comptes  rcndus,  xix.  Gil.  t  Qorbardt,  Chimie  Organique,  i.  71S. 


ACETIC  ACID. 


The  proportion  of  acetic  acid  in  aqueous  mixtures  may  therefore  be  ascertained,  within 
certain  limits,  by  determination  of  the  specific  gravity.     See  Acetimetry. 

The  following  table,  by  Mohr,  indicates  the  percentage  of  acetic  acid  in  mixtures  of 
different  specific  gravities  ;  but  of  course  this  is  only  applicable  in  cases  where  no  sugar  or 
other  bodies  are  present,  which  increase  the  specific  gravity. 

Abstract  of  Mohr'' s  Table  of  the  Specif  c  Gravity  of  Mixtures  of  Acetic  Acid  and  Water.* 


Percentapre  of  Acetic 
Acid,  C4  H«  0*. 

Density. 

Percentase  of  Acetic 
Acid,  C*  H<  0\ 

Density. 

100 

1-0635 

45 

1-055 

95 

1-070 

40 

1-051 

90 

l-O'ZS 

35 

1-046 

85 

1-073 

30 

1-040 

80 

1-0735 

25 

1-034 

75 

1-072 

20 

1-027 

1Q 

1-070 

15 

1-022 

65 

1-068 

10 

1-015 

60 

1-067 

5 

1-0067 

55 

1-064 

1 

1-001 

50 

1-060 

Which  numbers  closely  agree  with  those  obtained  by  Dr.  Ure.     See  vol.  i.  p.  5. 

Acetic  acid  was  formerly  (and  is  still  by  some  chemists)  viewed  as  the  hydrated*teroxJde 
of  a  radical  acetyl,  now  called  vinyl.     See  Chemical  Formula. 

(C«  H=)  0',  HO 
Acetyl. 

And  therefore  an  anhydrous  acetic  acid,  C  H'  0^,  is  supposed  to  exist.  Many  attempts 
have  been  made  to  isolate  this  anhydrous  acetic  acid  C*  H^  0^ ;  and  a  body  which  has  re- 
ceived this  name  has  been  quite  recently  obtained  by  Gerhardtf ,  by  the  double  decomposi- 
tion of  chloride  of  acetyl  and  an  alkaline  acetate,  thus : — 


C*H'(0'C1)   +     KO,C*H^O=' 


Chloride  of 
acetyl. 


Acetate  of 
potash. 


-     C'^H^O"    -f-    K  CI 

(So-called)  Chloride  of 
Anhydrous  potassium, 
acetic  acid. 


This  body  Gcrhardt  describes  as  a  colorless  liquid  having  a  strong  smell  of  acetic  acid, 
but  associated  with  the  flavor  of  hawthorne  blossom,  having  a  specific  gravity  of  1-073,  and 
boiling  at  137°  C.  (278°  F.) ;  falling  in  water  in  the  form  of  oily  drops,  only  dissolving  on 
gently  heating  that  fluid.  It  is,  however,  not  anhydrous  acetic  acid,  but  a  compound  iso- 
meric with  the  hypothetical  anhydrous  acetic  acid  C*  H^  0^,  containing,  in  fact,  double  the 
amount  of  matter,  its  formula  being  C"  IP  0". 

The  impure  varieties  of  acetic  acid  known  as  vinegar,  pyroligneous  acid,  &c.,  are  the 
products  met  with  in  commerce,  and  therefore  those  require  more  minute  description  in  this 
\vork. 

Before  describing  the  manufacture  of  these  commercial  articles,  it  may  be  interesting  to 
iillude  to  a  method  of  oxidizing  alcohol  by  means  of  spongy  platinum  ;  which  may  yet  meet 
with  extensive  practical  application.  It  is  a  well-known  fact  that  spongy  platinum  (c.  (j. 
|)latinum  black),  from  its  minute  state  of  division,  condenses  the  oxygen  of  the  air  within 
its  pores ;  consequently,  when  the  vapor  of  alcohol  comes  in  contact  with  this  body,  a  supply 
<jf  oxygen  in  a  concentrated  state  is  presented  to  it,  and  the  platinum,  without  losing  any 
of  its  properties,  effects  the  comljination  between  the  oxygen  and  the  alcohol,  converting  the 
latter  into  acetic  acid. 

This  may  be  illustrated  by  a  very  simple  experiment.  Place  recently  ignited  spongy 
platinum,  loosely  distributed  on  a  platinum-gauze,  at  a  short  distance  over  a  saucer  contain- 
ing warm  alcohol,  the  whole  standing  under  a  bell-glass  supported  by  wedges  on  a  glass 
dish,  so  that,  on  removing  the  stopper  from  the  bell-glass,  a  slow  current  of  air  circulates 
through  the  apparatus ;  the  spongy  platinum  soon  begins  to  glow,  in  consequence  of  the 
combustion  going  on  upon  its  surface,  and  acetic  acid  vapors  arc  abundantly  produced,  which 


*  Mohr,  Ann.  der  Chem.  und  Phar.  xxxi.  227. 


t  Comptes  rendus,  xxxiv.  755. 


ACETIC  ACID. 


condense  and  run  do^vn  the  sides  of  the  glass.     The  simultaneous  formation  of  aldehyde  is, 
at  the  same  time,  abundantly  proved  by  its  peculiar  odor. 

In  Germany  this  method  has  been  actually  carried  out  on  the  large  scale,  and,  if  it  were 
not  for  the  high  price  of  platinum,  and  the  heavy  duty  on  alcohol,  it  might  be  extensively 
employed  in  this  country,  on  account  of  its  elegance  and  extreme  simplicity. 

Manufacture  of  Vinegar  by  Acetous  Fermentation. — All  hquids  which  are  susceptible 
of  the  vinous  fermentation  are  capable  of  yielding  vinegar.  A  solution  of  sugar  is  the 
essential  ingredient,  which  is  converted  first  into  alcohol,  and  subsequently  into  acetic 
acid.  The  liquids  employed  vary  according  to  circumstances.  In  this  country  the  vine- 
gar of  commerce  is  obtained  from  an  infusion  of  malt,  and  in  wine  countries  from  inferior 
wines. 

The  oxidation  of  alcohol  is  remarkably  facilitated  by  the  presence  of  nitrogenized 
organic  bodies  in  a  state  of  change,  called  ferments,  hence  the  process  is  frequently  termed 
acetous  fermentation.  Now,  although  in  most  cases  the  presence  of  these  ferments  curi- 
ously promotes  the  process,  yet  they  have  no  specific  action  of  this  kind ;  for  we  have 
already  seen  that,  by  exposure  to  air  in  a  condensed  state,  alocohol,  even  when  pure,  is 
converted  into  acetic  acid  ;  and,  moreover,  the  action  of  oxidizing  agents,  such  as  chromic 
and  nitric  acid,  &c.,  is  capable  of  effecting  this  change. 

However,  in  the  presence  of  a  ferment,  with  a  free  supply  of  air,  and  at  a  temperature 
of  from  60'  to  90'  F.,  alcohol  is  abundantly  converted  into  acetic  acid. 

At  the  same  time  that  the  alcohol  is  converted  into  acetic  acid,  the  nitrogenized  and 
other  organic  matters  undergo  peculiar  changes,  and  often  a  white  gelatinous  mass  is  de- 
posited,— which  contains  Vibrioncs  and  other  of  the  lower  forms  of  organized  beings, — and 
which  has  received  the  name  of  mother  of  vinegar,"*^-  from  the  supposition  that  the  for- 
mation and  development  of  this  body,  instead  of  being  a  secondary  result  of  the  process, 
was  really  its  exciting  cause. 

Wine  vinegar  is  of  two  kinds,  U'ldte  and  reel,  according  as  it  is  prepared  from  white  or 
red  wine.  White  urine  vinegar  is  usually  preferred,  and  that  made  at  Orleans  is  regarded 
as  the  best.  Dr.  Ure  found  its  average  specific  gravity  to  be  I'OIO,  and  to  contain  from  6i 
to  7  per  cent,  of  real  acid  ;  according  to  the  Edinburgh  Pharmacopoeia,  its  specific  gravity 
varies  from  1-014  to  1-022. 

1.  Malt  Vinegar.  {British  Vinegar;  in  Germany  called  3Iah-Geireide  or  Sicr- 
essig.)  In  England  vinegar  is  chiefly  made  from  an  infusion  of  malt,  by  first  exciting  in  it 
the  alcoholic  fermentation,  and  subsequently  inducing  the  oxidation  of  the  alcohol  into 
acetic  acid. 

The  transformation  of  the  fermented  wort  into  vinegar  was  formerly  effected  in  two 
v,'ays,  which  were  entirely  opposite  in  their  manner  of  operation.  In  one  case  the  casks 
containing  the  fermented  malt  infusion  (or  gyle)  were  placed  in  close  rooms,  maintained  at 
a  uniform  temperature ;  in  the  other,  they  were  arranged  in  rows  in  an  open  field,  where 
they  remained  many  months.  As  regards  the  convenience  and  interests  of  the  manufac- 
turer, it  appears  that  each  method  had  its  respective  advantages,  l)ut  both  are  now  almost 
entirely  abandoned  for  the  more  modern  processes  to  be  described — a  short  notice  of 
the  fielding  process  is,  however,  retained. 

"When  fielding  is  resorted  to,  it  must  be  commenced  in  the  spring  months,  and  then  left 
to  complete  itself  during  the  warm  season.  The  fcldivg  method  requires  a  much  larger 
extent  of  space  and  utensils  than  the  stoving  process.  The  casks  are  placed  in  several 
parallel  tiers,  with  their  bung  side  upwards  and  left  open.  Beneath  some  of  the  paths 
which  separate  the  rows  of  casks  are  pipes  communicating  with  the  "  hack  "  at  the  top  of 
the  brewhouse  ;  and  in  the  centre  of  each  is  a  valve,  opening  into  a  concealed  pipe.  When 
the  casks  are  about  to  be  filled,  a  flexible  hose  is  screwed  on  to  this  opening,  the  other  end 
being  inserted  into  the  bung-hole  of  the  cask,  and  the  liquor  in  the  "■  gijle  back"  at  the 
brewhouse,  by  its  hydrostatic  pressure,  flows  through  the  underlying  pipe  and  hose  into  the 
cask.  The  hose  is"  so  long  as  to  admit  of  reaching  all  the  casks  in  the  same  row,  and  is 
guided  by  a  workman. 

After  some  months  the  vinegar  is  made,  and  is  drawn  off  l)y  the  following  operation : — 
A  long  trough  or  sluice  is  laid  by  the  side  of  one  of  the  rows  of  casks,  into  which  the 
vinegar  is  transferred  by  means  of  a  syphon,  whose  shorter  limb  is  inserted  into  the  bung- 
hole  of  the  cask.  The  trough  inclines  "a  little  from  one  end  to  the  other,  and  its  lower  end 
rests  on  a  kind  of  travelling  tank  or  cistern,  wherein  the  vinegar  from  several  casks  is  col- 
lected. A  hose  descends  from  the  tank  to  the  open  valve  of  an  underground  pipe,  which 
terminates  in  one  of  the  buildings  or  stores,  and,  by  the  agency  of  a  steam  boiler  and 
machinery,  the  pipe  is  exhausted  of  its  air,  and  this  causes  the  vinegar  to  flow  through  the 
hose  into  the  valve  of  the  pipe,  and  thence  into  the  factory  buildings.  By  this  arrange- 
ment the  whole  of  the  vinegar  is  speedily  drawn  off.  From  the  storehouse,  where  the 
vinegar  is  received,  it  is  pumped  into  the  refining  or  rape  vessels. 

*  This  substance  has  been  supposed  by  some  to  be  a  fungus,  and  has  been  described  by  Mulder  under 
the  name  of  MycoiEderm  Acetl. 


ACETIC  ACID.  9 

These  rape  vessels  are  generally  filled  with  the  stalks  and  skins  of  grapes  or  raisins, 
(the  refuse  of  the  British  wine  manufacturer  is  generally  used,)  and  the  liquor  being 
admitted  at  the  top,  is  allowed  slowly  to  filter  througli  them  ;  after  passing  through,  it  is 
pumped  up  again  to  the  top,  and  this  process  is  repeated  until  the  cacetification  is  complete. 
Sometimes  wood  shavings,  straw,  or  spent  tan,  are  substituted  for  the  grape  refuse,  but  the 
latter  is  generally  preferred. 

By  this  process,  not  only  is  the  oxidation  of  the  alcohol  completed,  but  coagulable  nitro- 
genous and  mucilaginous  matter  is  separated,  and  thus  the  vinegar  rendered  briijht.  It  is 
finally  pumped  into  store  vats,  where  it  is  kept  until  put  into  casks  for  sale. 

2.  Sugar,  Cider,  Fruit,  and  Beet  Vinegars.  An  excellent  vinegar  may  be  made  for 
domestic  purposes  by  adding,  to  a  syrup  consisting  of  one  pound  and  a  quarter  of  sugar 
for  every  gallon  of  watei',  a  quarter  of  a  pint  of  good  yeast.  The  liquor  being  maintained 
at  a  heat  of  from  75°  to  80°  F.,  acetification  will  proceed  so  well  that  in  2  or  3  days  it  may 
be  racked  off  from  the  sediment  into  the  ripening  cask,  where  it  is  to  be  mixed  with  1  oz. 
of  cream  of  tartar  and  1  oz.  of  crushed  raisins.  When  completely  freed  from  the  sweet 
taste,  it  should  be  drawn  off  clear  into  bottles,  and  closely  corked  up.  The  juices  of  cur- 
rants, gooseberries,  and  many  other  indigenous  fruits,  may  be  acetified  either  alone  or  in 
combination  with  syrup.  Vinegar  made  by  the  above  process  from  sugar  should  have  fully 
the  Revenue  strength.  It  will  keep  much  better  than  malt  vinegar,  on  account  of  the 
absence  of  gluten,  and  at  the  present  low  price  of  sugar  will  not  cost  more,  when  fined 
upon  beech  chips,  than  Is.  per  gallon. 

The  sugar  solution  may  likewise  be  replaced  by  honey,  cider,  or  any  other  alcoholic  or 
saccharine  liquid.  An  endless  number  of  prescriptions  exist,  of  which  the  following  example 
may  suffice  : — 100  parts  of  water  to  13  of  brandy,  4  of  honey,  and  1  of  tartar. 

Messrs.  Neale  and  Duyck,  of  London,  patented  a  process,  in  1841,  for  the  manufacture 
of  vinegar  from  beet-root. 

The  saccharine  juice  is  pressed  out  of  the  beet,  previously  rasped  to  a  pulp,  then  mixed 
with  water  and  boiled ;  this  solution  is  fermented  with  yeast,  and  finally  acetified  in  the 
usual  way,  the  process  being  accelerated  by  blowing  air  up  through  the  liquid,  which  is 
placed  in  a  cylindrical  vessel  with  fine  holes  at  the  bottom. 

In  some  factories  large  quantities  of  sour  ale  and  beer  are  converted  into  vinegar ;  but 
it  is  usually  of  an  inferior  quality,  in  consequence  of  being  liable  to  further  fermentation. 

Dr.  Stenhouso  has  shown  that  when  sea-iveed  is  subjected  to  fermentation  at  a  tempera- 
ture of  96'  F.,  in  the  presence  of  lime,  acetate  of  lime  is  formed,  from  which  acetic  acid 
may  be  liberated  by  the  processes  described  under  the  head  of  Pyroligneous  Acid.  Although 
such  large  quantities  of  sea-weed  are  found  on  all  our  coasts,  it  does  not  yet  appear  that 
they  have  yet  been  utilized  in  this  way,  although  they  would  still  be,  to  a  certain  extent, 
valuable  as  manure  after  having  been  subjected  to  this  process. 

3.  The  German  or  Quick- Vinegar  Process.  (Sc/incllcssigbarilmig.) — In  the  manu- 
facture of  vinegur  it  is  highly  important  that  as  free  a  supply  of  air  should  be  admitted  to 
the  liquid  as  possible,  since,  if  the  oxidation  take  place  but  slowly,  a  considerable  loss  may 
be  sustained,  from  much  of  the  alcohol,  instead  of  being  completely  oxidized  to  acetic  acid, 
being  only  converted  into  aldehyde,  which,  on  account  of  its  volatility,  passes  off  in  the 
state  of  vapor.  This  is  secured  in  the  German  process  by  greatly  enlarging  the  surface 
exposed  to  the  air ;  which,  however,  not  only  diminishes  or  prevents  the  formation  of  alde- 
hyde, but  also  greatly  curtails  the  time  necessary  for  the  whole  process.  In  fact,  when  this 
method  was  first  introduced,  from  the  supply  of  air  being  insufficient,  very  great  loss  was 
sustained  from  this  cause,  which  was,  however,  easily  remedied  by  increasing  the  number 
of  air-holes  in  the  apparatus. 

This  quick-vinegar  procesa  consists  in  passing  the  fermented  liquor  (which  generally 
contains  about  50  gallons  of  brandy  of  60  per  cent.,  and  37  gallons  of  beer  or  maltwort, 
with  -j-^L^  of  ferment)  two  or  three  times  through  an  apparatus  called  the  Vinegar  Genera- 
tor (essigbilder).     See  Graduator,  vol.  i.  '' 

The  analogy  between  acetification  and  ordinary  processes  of  decay,  and  even  combustion, 
is  well  seen  in  this  process ;  for,  as  the  oxidation  proceeds,  the  temperature  of  the  liquid 
rises  to  100°  or  even  104°  F. ;  l)ut  if  the  temperature  generated  by  the  process  itself  be 
not  sufficient,  the  temperature  of  the  room  in  which  the  tuns  are  placed  should  be  artifi- 
cially raised. 

By  this  method  150  gallons  of  vinegar  can  be  manufactured  daily  in  ten  tuns,  wliich  one 
man  can  superintend;  and  the  vinegar,  in  purity  and  clearness,  resembles  distilled  vinegar. 

It  is  better  to  avoid  using  li(iuors  containing  much  suspended  mucilaginous  matter, 
whicli,  collecting  on  the  chips,  quickly  chokes  up  the  apparatus,  and  not  only  impedes  the 
process,  but  contaminates  the  product. 

The  chips  and  sliavings  may  with  advantage  be  replaced  by  charcoal  in  fragments,  which, 
by  the  oxygen  it  contains  condensed  in  its  pores,  still  further  accelerates  the  process.  The 
charcoal  would,  of  course,  require  re-igniting  from  time  to  time. 

B;/  desfructiue  Distilhilion  of  Wood.     Pyroligneous  Acid. — The  general  nature  of  the 


10 


ACETIC  ACID. 


process  of  destructive  distillation  will  be  found  detailed  under  the  head  of  Distillation 
Dkstructite  ;  as  well  as  a  list  of  products  of  the  rearrangement  of  the  molecules  of  organic 
bodies  under  the  influence  of  heat  in  closed  vessels.  We  shall,  therefore,  at  once  proceed 
to  the  details  of  the  process  as  specially  applied  in  the  manufacture  of  acetic  acid  from  wood. 
The  forms  of  apparatus  very  generally  employed  on  the  continent  for  obtaining  at  the 
same  time  crude  acetic  acid,  charcoal,  and  tar,  are  those  of  Schwartz  and  Rcichenbach  ;  but  in 
France  the  process  is  carried  out  with  special  reference  to  the  production  of  acetic  acid  alone. 
Since  the  carbonizers  of  Rcichenbach  and  Schwartz  are  employed  with  special  reference 
to  the  manufacture  of  wood  charcoal,  the  condensation  of  the  volatile  products  bein"-  only 
a  secondary  consideration,  they  will  be  more  appropriately  described  under  the  head  of 
Charcoal. 

In  England  the  distillation  is  generally  carried  out  in  large  iron  retorts,  placed  horizon- 
tally in  the  furnace,  the  process,  in  fact,  closely  resembling  the  distillation  of  coal  in  the 

manufacture  of  coal  gas, 
1  excepting  that  the  retorts 

are  generally  larger,  be- 
ing sometimes  4  feet  in 
diameter,  and  6  or  8  feet 
long.  Generally  two,  or 
even  three,  are  placed  in 
each  furnace,  as  shown  in 
fg.  1,  so  that  the  fire  of 
the  single  furnace,  a, 
plays  all  round  them. 
The  doors  for  ciiarging 
the  retorts  are  at  one  end, 
6,  {f(j.  2),  and  the  pipe 
for  carrying  off  the  vola- 
tile products  at  the  other, 
c,  by  which  they  are  con- 
ducted, first  to  the  tar- 
condenscr,  d,  and  finally 
through  a  worm  in  a  large 
tub,  f,  where  the  crude 
acetic  acid  is  collected. 

Of  course,  in  different 
localities  an  endless  va- 
riety of  modifications  of 
the  process  are  employed. 
In  the  Forest  of  Dean, 
instead  of  cylindrical  i-e- 
torts,  square  sheet-iron 
boxes  are  used,  4  ft.  C  in. 
by  2  ft.  9  in.,  which  are 
heated  in  large  square 
ovens. 

With  regard  to  the 
relative  advantages  of 
cylindrical  retorts  or 
square  boxes,  it  should 
be  remarked  that  the 
cylinders  are  more 
adapted  for  the  distilla- 
tion of  the  large  billets 
of  Gloucestershire,  and 
the  refuse  ship  timber  of 
Glasgow,  Newcastle,  and 
Liverpool  ;  but,  on  tlie 
other  hand,  where  light 
wood  is  used,  such  as  that  generally  carbonized  in  the  Welsh  factories,  the  square  ovens 
answer  better. 

The  most  recent  and  ingenious  improvement  in  the  manufacture  of  pyroligneous  acid  is 
that  patented  by  the  late  Mr.  A.  G.  Halliday,  of  Manchester,  and  adopted  by  several  large 
manufacturers.  The  process  consists  in  effecting  the  destructive  distillation  of  waste  mate- 
rials, such  as  saw-dust  and  spent  dye-wood.«,  by  causing  them  to  pass  in  continuous  motion 
through  heated  retorts.  For  this  purpose  the  materials,  which  are  almost  in  a  state  of 
powder,  are  introduced  into  a  hopper,  h  {fg.   8),  whence  they  descend  into  the  retort,  b, 


* 

'-'f- 

\i'"::r\ 

i 
■ 

1 
1 
i 

1 

ifiii 

ijiinii 

t 

i!iirii' 
¥!ri!i 

I 

JJlf 


5g^g>  d 


ACETIC  ACID. 


11 


being  kept  all  the  while  in  constant  agitation,  and  at  the  same  time  moved  forward  to  the 
other  end  of  the  retort  by  means  of  an  endless  screw,  s.  By  the  time  they  ai-rive  there,  the 
charge  has  been  completely  carbonized,  and  all  the  pyroligneous  acid  evolved  at  the  exit 
tube,  t.  The  residuary  charcoal  falls  through  the  pipe  d  into  a  vessel  of  water,  e,  whilst  the 
v^Jkile  products  escape  at  f,  and  are  condensed  in  the  usual  way. 

^^everal  of  these  retorts  are  generally  set  in  a  furnace  side  by  side,  the  retorts  are  only 
14  inches  in  diameter,  and  eigiit  of  these  retorts  produce  in  24  hours  as  much  acid  as  IG 
retorts  3  feet  in  diameter  upon  the  old  system.  In  the  manufacturing  districts  of  Lancashire 
and  Yorkshire,  where  such  immense  quantities  of  spent  dye-woods  accumulate,  and  have 
proved  a  source  of  annoyance  and  expense  for  their  removal,  this  process  has  afforded  a 
most  important  means  of  economically  converting  them  into  valuable  products — charcoal 
and  acetic  acid. 

Mention  should  also  be  made  of  Messrs.  Solomons  and  Azulay's  patent  for  employing 
superheated  steam  to  effect  the  carbonization  of  the  wood,  which  is  passed  directly  into  the 
mass  of  materials.  Since  the  steam  accompanies  the  volatile  products,  it  necessarily  dilutes 
the  acid  ;  but  this  is  in  a  great  degree  compensated  for  by  employing  these  vapors  to  con- 
centrate the  distilled  products,  by  causing  them  to  traverse  a  coil  of  tubing  placed  in  a  pan 
of  the  distillates. 

As  regards  the  yield  of  acetic  acid  from  the  different  kinds  of  wood,  some  valuable  facts 
have  been  collected  and  tabulated  by  Stoize,  in  his  work  on  Pyroligneous  Acid  : — 


Carbonate  of 

One 

Pound  of  Wood. 

■\Voislit  of 
Acid. 

Potassa  ncii- 

tralized  by 

One  Oiinceof 

Acid. 

TTciL'bt  <if 
Charcoal. 

ozs. 

prs. 

ozs. 

White  birch    - 

-  Betulaalba         ... 

H 

55 

31 

Red  birch 

-  Fagus  svlvatica 

7 

54 

3^ 

Large-leaved  linden   Tilia  pataphylla 

c^- 

52 

3|' 

Oak 

-  Qucrcus  robur   - 

G| 

50 

H 

Ash 

-  Fraxinus  excelsior 

H 

44 

3* 

Horse  chestnut 

-  Esculus  hippocastanus 

n 

41 

U 

Lombardy  poplar 

-  Populus  dilatata 

n 

40 

H 

White  poplar 

-  Populus  alba 

#^1 

r.9 

3? 

Bird  cherry     - 

-  Pruuus  padus     -         -         - 

7 

37 

8.^ 

.  Basket  willow 

-  Salix          .... 

'?i 

35 

S.V 

Buckthorn 

-  Rhamnus  -         -         -         - 

H 

34 

3i 

Logwood 

-  Hematoxylou  campechianum 

n 

So 

2 

Alder 

.  -  Alnus         .... 

11 

30 

Si 

Juniper  - 

-  Jmiipcrus  communis  - 

u 

29 

3^ 

White  fir 

-  Pinus  abics         .         .         . 

6|- 

29 

3| 

Common  pine 

-  Pinus  svlvcstris 

CJ 

28 

3* 

Common  savine 

-  Junipcrus  sabina 

7 

27 

3| 

Red  fir    - 

-  Abies  pcctinata 

Of 

25 

H 

II 


12 


ACETIC  ACID. 


Properties  of  the  crude  PyroUgneous  Acid. — The  crude  pyroligneous  acid  possesses  the 
properties  of  acetic  acid,  combined  with  those  of  the  pyrogenoiis  bodies  with  which  it  is 
associated.  As  first  obtained,  it  is  black  from  the  large  quantity  of  tar  which  it  holds  in 
solution  ;  and  although  certain  resins  are  removed  by  redistillation,  yet  it  is  impossible  to 
remove  some  of  the  empyreumatic  oils  by  this  process,  and  a  special  purification  is  necessary. 

In  consequence  of  the  presence  of  creosote,  and  other  antiseptic  hydrocarbons,  in  the 
crude  pyroligneous  acid,  it  possesses,  in  a  very  eminent  degree,  anti-putrescent  properties. 
Flesh  steeped  in  it  for  a  few  hours  may  be  afterwards  dried  in  the  air  without  corrupting  ; 
but  it  becomes  hard,  and  somewhat  leather-like  :  so  that  this  mode  of  preservation  does  not 
answer  well  for  butcher's  meat.     Fish  are  sometimes  cured  with  it. 

Purijication  of  Pyroligneous  Acid. — This  is  effected  either,  1st,  by  converting  it  into 
an  acetate, — acetate  of  lime  or  soda, — and  then,  after  the  purification  of  these  salts  by 
exposure  to  heat  sufficient  to  destroy  the  tar,  and  repeated  recrystalhzation,  liberating  the 
acid  again  by  distilling  with  a  stronger  acid,  e.  g.  sulphuric. 

Or,  2d,  by  destroying  the  pyrogenous  impurities  by  oxidizing  agents,  such  as  binoxide 
of  manganese  in  the  presence  of  sulphuric  acid,  &c. 

The  former  is  the  method  generally  adopted. 

After  the  naphtha  has  been  expelled,  the  acid  liquor  is  nm  off  into  tanks  to  deposit  part 
of  its  impurities  ;  it  is  then  syphoned  off  into  another  vessel,  in  which  is  either  milk  of  lime, 
quicklime,  or  chalk  ;  the  mixture  is  boiled  for  a  short  time,  and  then  allowed  to  stand  for 
24  hours  to  deposit  the  excess  of  lime  with  any  impurities  which  the  latter  will  carry  down 
with  it.     The  supernatant  liquor  is  then  pumped  into  the  evaporating  pans. 

The  evaporation  is  effected  either  by  the  heat  of  a  fire  applied  beneath  the  evaporating 
pans,  or  more  frequently  by  a  coil  of  pipe  in  the  liquor,  through  which  steam  is  passed — 
the  liquor  being  kept  constantly  stirred,  and  the  impurities  which  rise  to  the  surface  during 
the  process  carefully  skimmed  off. 

From  time  to  time,  as  the  evaporation  advances,  the  acetate  of  lime  which  separates  is 
removed  by  ladles,  and  placed  in  baskets  to  drain ;  and  the  residual  mother  liquoi^J^ 
evaporated  to  dryness.  This  mass,  by  ignition,  is  converted  into  carbonate  of  lime  and 
acetone. 

If  the  acetate  of  lime  has  been  procured  by  directly  saturating  the  crude  acid,  it  is  called 
brown  acetate  ;  if  from  the  acid  once  purified  by  redistillation,  it  is  called  gray  acetate. 

From  this  gray  acetate  of  lime,  acetate  of  soda  is  now  prepared,  by  adding  sulphate  of 
soda  to  the  filtered  solution  of  the  acetate  of  lime.  In  performing  this  operation,  it  is  highly 
important  to  remember  that,  for  every  equivalent  of  acetate  of  lime,  it  is  necessary  to  add 
tvy  o  equivalents  of  sulphate  of  soda,  on  account  of  the  formation  of  a  double  sulphate  of  soda 
and  lime.     The  equation  representing  the  change  being  : — 

CaO,  C^  H^  0'    +     2(NaO,  S0=)     =      NaO.C^  IP  0'     +    CaO,  SOI    XaO,  80=" 


Acetate  of  lime. 


Acetate  of  soda. 


Double  salt. 


Or,  if  sulphuric  acid  be  considered  as  a  bibasic  acid,  which  this  very  reaction  so  strong 
justifies — 

C^  n=  (Ca)  0*       +       Na^  S"  0«       =       C^  H'  (Na)  0^       -f       ^-'^   I  S=  0" 


Acetate  of  lime.        Sulphate  of  soda.       Acetate  of  soda. 


Double  salt. 


If  this  point  be  neglected,  and  only  one  equivalent  of  sulphate  of  soda  be  used,  one-half  of 
the  acetate  of  lime  may  escape  decomposition,  and  thus  be  lost. 

After  the  separation  of  the  double  salt,  the  solution  of  acetate  of  soda  is  drawn  off,  any 
impurities  allowed  to  subside,  and  then  concentrated  by  evaporation  until  it  has  a  density 
of  4-3 — when  the  acetate  of  soda  crystallizes  out,  and  may  be  further  purified,  if  requisite, 
by  another  re-solution  and  re-crystallization.  The  contents  of  the  mother  liquors  are  con- 
verted into  acetone  and  carbonate  of  soda,  as  before. 

The  crystallized  acetate  of  soda  is  now  fused  in  an  iron  pot,  at  a  temperature  of  about 
400°,  to  drive  off  the  water  of  crystallization,  the  mass  being  kept  constantly  stirred.  A 
stronger  heat  must  not  be  applied, %)r  we  should  effect  the  decomposition  of  the  salt. 

For  the  production  of  the  acetic  acid  from  this  salt,  a  quantity  of  it  is  put  into  a  stout 
copper  still,  and  a  deep  cavity  made  in  the  centre  of  the  mass,  into  which  sulphuric  acid  of 
specific  gravity  1-84  is  poured  in  the  proportion  of  35  per  cent,  of  the  weight  of  the  salt; 
the  walls  of  the  cavity  are  thrown  in  upon  the  acid,  the  whole  briskly  agitated  with  a  wooden 
spatula.  The  head  of  the  still  is  then  luted,  and  connected  with  the  condensing  worm,  and 
the  distillation  carried  on  at  a  very  gentle  heat.  The  worm  should  be  of  silver  or  porcelain, 
as  also  the  still  head  ;  and  even  silver  solder  should  be  used  to  connect  the  joinings  in  the 
body  of  the  still.    The  still  is  now  generally  heated  by  a  steam  "jacket."    See  Distillation. 

The  acid  which  passes  over  is  nearly  colorless,  and  has  a  specific  gravity  of  1*05.     That 


ACETIC   ACID.  13 

which  collects  at  the  latter  part  of  the  operation  is  liable  to  be  somewhat  empyreumatic,  and 
therefore,  before  this  point  is  reached,  the  receiver  should  be  changed  ;  and  throughout  the 
entire  operation,  care  should  be  taken  to  avoid  applying  too  high  a  temperature,  as  the 
flavor  and  purity  of  the  acid  will  invariably  suffer. 

Any  trace  of  empyreuma  may  be  removed  from  the  acid  by  digestion  with  animal  char- 
coal and  redistillation. 

A  considerable  portion  of  this  acid  crystallizes  at  a  temperature  of  from  40°  to  50°  F., 
constituting  what  is  called  glacial  acetic  acid,  which  is  the  compound  C^  H*  0*  (or  C^*  H^ 

0',  HO).    °  .    ^.  . 

For  culinary  purposes,  pickling,  &c.,  the  acid  of  specific  gravity  1-05  is  diluted  with  five 
times  its  weight  in  water,  which  renders  it  of  the  same  strength  as  Revenue  proof  vinegar. 

Several  modifications  and  improvements  of  this  process  have  recently  been  introduced, 
which  require  to  be  noticed. 

The  following  process  depends  upon  the  difficult  solubility  of  sulphate  of  soda  in  strong 
acetic  acids : — 100  lbs.  of  the  pulverized  salt  being  put  into  a  hard  glazed  stoneware  re- 
ceiver, or  deep  pan,  from  35  to  36  lbs.  of  concentrated  sulphuric  acid  are  poured  in  one 
stream  upon  the  powder,  so  as  to  flow  under  it.  The  mixture  of  the  salt  and  acid  is  to  be 
made  very  slowly,  in  order  to  moderate  the  action  and  the  heat  generated,  as  much  as 
possible.  '  After  the  materials  have  been  in  intimate  contact  for  a  few  hours,  the  decompo- 
sition is  effected  ;  sulphate  of  soda  in  crystalline  grains  will  occupy  the  bottom  of  the  vessel 
and  acetic  acid  the  upper  portion,  partly  liquid  and  partly  in  crystals.  A  small  portion  of 
pure  acetate  of  lime  added  to  the  acid  will  free  it  from  any  remainder  of  sulphate  of  soda, 
leaving  only  a  little  acetate  in  its  place  ;  and  though  a  small  portion  of  sulphate  of  soda  may 
still  remain,  it  is  unimportant,  whereas  the  presence  of  any  free  sulphuric  acid  would  be 
very  injurious.  This  is  easily  detected  by  evaporating  a  little  of  the  liquid,  at  a  moderate 
heat,  to  dryness,  when  that  mineral  acid  can  be  distinguished  from  the  neutral  soda  sulphate. 
This  plan  of  superseding  a  troublesome  distillation,  which  is  due  to  M.  MoUerat,  is  one  of 
the  greatest  improvements  in  this  process,  and  depends  upon  the  insolubility  of  the  sulphate 
of  soda  in  acetic  acid.  The  sulphate  of  soda  thus  recovered,  and  well  drained,  serves  anew 
to  decompose  acetate  of  lime  ;  so  that  nothing  but  this  cheap  earth  is  consumed  in  carrying 
on  the  manufacture.  To  obtain  absolutely  pure  acetic  acid,  the  above  acid  has  to  be  distilled 
in  a  glass  retort. 

Volckel  recommends  the  use  of  hydrochloric  instead  of  sulphuric  acid  for  decomposing 
the  acetate. 

The  following  is  his  description  of  the  details  of  the  process : — 

"  The  crude  acetate  of  lime  is  separated  from  the  tarry  bodies  which  are  deposited  on 
neutralization,  and  evaporated  to  about  one-half  its  bulk  in  an  iron  pan.  Hydrochloric  acid 
is  then  added  until  a  distinctly  acid  reaction  is  produced  on  cooling ;  by  this  means  the 
resinous  bodies  are  separated,  and  come  to  the  surface  of  the  boiling  liquid  in  a  melted 
state,  whence  they  can  be  removed  by  skimming,  while  the  compounds  of  lime,  with  creo- 
sote, and  other  volatile  bodies,  are  likewise  decomposed,  and  expelled  on  further  evapora- 
tion. From  4  to  6  lbs.  of  hydrochloric  acid  for  every  33  gallons  of  wood  vinegar  is  the 
average  c(uantity  required  for  this  purpose.  The  acetate,  having  been  dried  at  a  high  tem- 
perature on  iron  plates,  to  char  and  drive  off  the  remainder  of  the  tar  and  resinous  bodies, 
is  then  decomposed,  by  hydrochloric  acid,  in  a  still  with  a  copper  head  and  leaden  condens- 
ing tube.  To  every  100  lbs.  of  salt  about  90  to  95  lbs.  of  hydrochloric  acid  of  specific 
gravity  1-16  are  required.  The  acid  comes  over  at  a  temperature  of  from  100°  to  120^  C. 
(212"  to  218°  F.),  and  is  very  slightly  impregnated  with  empyreumatic  products,  while  a 
mere  cloud  is  produced  in  it  by  nitrate  of  silver.  The  specific  gravity  of  the  product  varies 
fro:n  I'OSS  to  I'OGl,  and  contains  more  than  40  per  cent,  of  real  acid ;  but  as  it  is  seldom 
required  of  this  strength,  it  is  well  to  dilute  the  90  parts  of  hydrochloric  acid  with  25  parts 
of  water.  These  proportions  then  yield  from  95  to  100  parts  of  acetic  acid  of  specific 
gravity  1"015. 

This  process  is  recommended  on  the  score  of  economy  and  greater  purity  of  product. 
The  volatile  empyreumatic  bodies  are  said  to  be  more  easily  separated  by  the  use  of  hydro- 
chloric than  sulphuric  acid  ;  moreover,  the  chloride  of  calcium  being  a  more  easily  fusible 
salt  than  the  sulphate  of  lime,  or  even  than  the  double  sulphafe  of  lime  and  soda,  the  acetic 
acid  is  more  freely  evolved  from  the  mixture.  The  resinous  bodies  also  decompose  sulphuric 
acid  towards  the  end  of  the  operation,  giving  rise  to  sulphurous  acid,  sulphuretted  hydrogen, 
&c.,  which  contaminate  the  product. 

Impuriiies  and  Adulterations. — In  order  to  prevent  the  putrefactive  change  which  often 
takes  place  in  vinegar  when  carelessly  prepared  by  the  fermentation  of  malt  wine,  &c.,  it 
was  at  one  time  supposed  to  be  necessary  to  add  a  small  quantity  of  sulphuric  acid.  This 
notion  has  long  since  been  shown  to  be  false  ;  nevertheless,  since  the  addition  of  1  part  of 
sulphuric  acid  to  1,000  of  vinegar  was  permitted  by  an  excise  regulation,  and  thus  the 
practice  has  received  legal  sanction,  it  is  still  continued  by  many  manufacturers.  Po  long 
as  the  quantity  is  retained  within  these  limits,  and  if  pure  sulphuric  acid  be  used  (great  care 


14 


ACETIMETRY. 


being  taken  that  there  is  no  arsenic  present  in  6uch  oil  of  vitriol,  as  is  not  unfrequently  the 
case  in  inferior  varieties),  no  danger  can  ensue  from  the  habit ;  but  occasionally  the  quantity 
is  much  overpassed  by  dishonei^t  dealers,  of  whom  it  is  to  be  hoped  there  are  but  few. 

Dr.  Ure  mentions  having  found,  by  analysis,  in  a  sample  of  vinegar,  made  by  one  of  the 
most  eminent  London  manufacturers,  with  which  he  supplied  the  public,  no  less  than  1*75 
grains  of  the  strongest  oil  of  vitriol  per  gallon,  added  to  vinegar  containing  only  3^^^  per 
cent,  of  real  acetic  acid,  giving  it  an  apparent  strength  after  all  of  only  4  per  cent.,  whereas 
standard  commercial  vinegar  is  i-ated  at  5  per  cent. 

The  methods  of  determining  sulphuric  acid  will  be  given,  once  for  all,  under  the  head 
of  AciuiMETUY,  and  therefore  need  not  be  described  in  every  case  where  it  occurs;  the 
same  remark  applies  to  hydrochloric  acid  and  others. 

Hydrochloric  acid  is  rarely  intentionally  added  to  vinegar ;  but  it  may  accidentally  be 
present  when  the  pyroligneous  acid  has  been  purified  by  Volckel's  process.  It  is  detected 
by  the  precipitate  which  it  gives  with  solution  of  nitrate  of  silver  in  the  presence  of  nitric  acid. 

Nitric  acid  is  rarely  found  in  vinegar.     For  its  method  of  detection,  see  Nitric  Acid. 

Wine  vinegar  generally  contains  tartaric  acid  and  tartrates  ;  but  it  is  purified  from  them 
by  distillation. 

Sulphurous  acid  is  occasionally  met  with  in  pyroligneous  acid.  This  is  recognized  by  its 
bleaching  action  on  delicate  vegetable  colors,  and  by  its  conversion,  under  the  influence  of 
nitric  acid,  into  sulphuric  acid,  which  is  detected  by  chloride  of  barium. 

Sulphuretted  hydrogen  is  detected  by  acetate  of  lead  giving  a  black  coloration  or  pre- 
cipitate. 

Metallic  SalU. — If  care  be  not  taken  in  constructing  the  worm  of  the  still  of  silver  or 
earthenware,  distilled  acetic  acid  is  frequently  contaminated  with  small  quantities  of  metal 
from  the  still,  copper,  lead,  tin,  &c.  These  metals  are  detected  by  the  addition  of  sulphu- 
retted hydrogen,  as  is  fully  discussed  under  the  head  of  the  individual  metals.  Copper  is  the 
most  commonly  found,  and  it  may  be  detected  in  very  minute  quantities  by  the  blue  color 
which  the  solution  assumes  on  being  supersaturated  with  ammonia. 

It  is  not  uncommon  to  add  to  pyroligneous  acid,  a  little  coloring  matter  and  acetic  ether, 
to  give  it  the  color  and  flavor  of  wine  or  malt  vinegar ;  but  this  can  hardly  be  called  an 
adulteration. 

The  presence  of  the  products  of  acetification  of  cider  may  be  detected  by  neutralizing 
the  vinegar  with  ammonia,  and  then  adding  solution  of  acetate  of  lime.  Tartrate  of  lime  is, 
of  course,  precipitated  from  tlie  wine  vinegar,  while  the  pearly  malic  acid  of  the  cider  aifords 
no  precipitate  with  the  lime,  but  may  be  detected  by  acetate  of  lead,  by  the  glistening  pearly 
scales  of  malate  of  lead,  hardly  soluble  in  the  cold. 

Acetic  acid  is  extensively  employed  in  the  arts,  in  the  manufacture  of  the  various  ace- 
tates, especially  those  of  alumina  and  iron,  so  extensively  employed  in  calico  printing  as 
mordants,  sugar  of  lead,  &c.  It  is  likewise  used  in  the  preparation  of  varnishes,  for  dis- 
solving gums  and  albuminous  bodies ;  in  the  culinary  arts,  especially  in  the  manufacture 
of  pickles  and  other  condiments  ;  in  medicine,  externally,  as  a  local  irritant,  and  internally, 
to  allay  fever,  &c. 

For  the  treatment  in  cases  of  poisoning,  we  refer  to  Taylor,  Pereira,  and  other  medical 
authorities. — II.  M.  W. 

ACETIMETRY.  DctcrmhiaHon  of  the  Strength  of  Vincr/ar. — If  in  vinegars  we  were 
dealing  with  mixtures  of  pure  acetic  acid  and  water,  the  determination  of  tlie  density  might, 
to  a  certain  extent,  afford  a  criterion  of  the  strength  of  the  solution  ;  but  vinegar,  especially 
that  obtained  from  wine  and  malt,  invariably  contains  gluten,  saccharine,  and  mucilaginous 
matters,  which  increase  its  density  and  render  this  method  altogether  fallacious. 

The  only  accurate  means  of  determining  the  strength  of  vinegar  is  by  ascertaining  the 
quantity  of  carbonate  of  soda  or  potash  neutralized  by  a  given  weight  of  the  vinegar  under 
examination.  This  is  performed  by  adding  to  tlie  vinegar  a  standard  solution  of  the  alka- 
line carbonate  of  known  strength  I'rom  a  bructte,  until,  after  boilirg  to  cxpd  the  carbonic 
acid,  a  solution  of  litmus  previously  introduced  into  the  liquid  is  distinctly  reddened. 

The  details  of  this  process,  which  is  equally  applicable  to  mineral  and  other  organic 
acids,  will  be  found  fully  described  under  the  head  of  Acidimethy. 

Roughly,  it  may  be  stated  that  every  53  grains  of  the  pure  anhydrous  carbonate  of 
soda,  or  every  G9  grains  of  carbonate  of  potassa  {/.  c.  one  equivalent),  correspond  to  GO 
grains  of  acetic  acid  (C*  11^  0').* 

It  is  obvious  that  preliminary  examinations  should  be  made  to  ascertain  if  sulphuric, 
hydrochloric,  or  other  mineral  acids  are  present ;  and,  if  so,  their  amount  determined, 
otherwise  they  will  be  reckoned  as  acetic  acid. 

The  British  malt  vinegar  is  stated  in  the  London  Pharmacopo?ia  to  require  a  drachm 

*  In  most  casps  wliere,  in  commercial  languasre,  mention  Is  made  of  real  acetic-  acid,  tho  hypotheti- 
cal compound  C^II'O'  is  meant;  b"t  it  would  be  better  In  future  always  to  give  the  percentaco  of 
acetic  acid  C'TT-'O''— for  the  body  C'TI'O^  is  altogether  hypotlietical— never  having  yet  been  discovered. 
Seo  tho  remarks  on  Anhydrous  Acetic  Acid  at  the  commencement  of  this  article. — il.  M.  W. 


ACETYL.  15 

(60  grains)  of  crystallized  carbonate  of  soda  (which  contains  10  equivalents  of  water  of 
crystallization)  for  saturating  a  fluid  ounce,  or  4"46  grains  ;  it  contains,  in  fact,  from  4 '6  to 
6  per  cent,  of  real  acetic  acid. 

The  same  authorities  consider  that  the  purified  pyroligneous  acid  should  require  87 
grains  of  carbonate  of  soda  for  saturating  100  grains  of  the  acid. 

Dr.  Ure  suggests  the  use  of  the  bicarbonate  of  potash.  Its  atomic  weight,  referred  to 
hydrogen  as  unity,  is  100-584,  while  the  atomic  weight  of  acetic  acid  is  51-563;  if  we 
estimate  2  grains  of  the  bicarbonate  as  equivalent  to  1  of  the  real  acid,  we  shall  commit  no 
appreciable  error.  Hence  a  solution  of  the  carbonate  containing  200  grains  in  100 
measures  will  form  an  acetimeter  of  the  most  perfect  and  convenient  kind  ;  for  the  meas- 
ures of  test  liquid  expended  in  saturating  any  measure — for  instance,  an  ounce  or  1,000 
grains  of  acid — will  indicate  the  number  of  grains  of  real  acetic  acid  in  that  quantity. 
Thus,  1,000  grains  of  the  above  proof  would  require  50  measures  of  the  acetimetrical  alka- 
line solution,  showing  that  it  contains  50  grains  of  real  acetic  acid  in  1,000,  or  5  per  cent. 

Although  the  bicarbonate  of  potash  of  the  shops  is  not  absolutely  constant  in  compo- 
sition, yet  the  method  is  no  doubt  accurate  enough  for  all  practical  purposes. 

The  acetimetrical  method  employed  by  the  Excise  is  that  recommended  by  Messrs.  J. 
and  P.  Taylor,*  and  consists  in  estimating  the  strength  of  the  acid  by  the  specific  gravity 
which  it  acquires  when  saturated  by  hydrate  of  lime.  Acid  which  contains  5  per  cent,  of 
real  acid  is  equal  in  strength  to  the  best  malt  vinegar,  called  by  the  makers  No.  24,  and  is 
assumed  as  the  standard  of  vinegar  strength,  under  the  denomination  of  "  proof  vinegar."-j- 
Acid  which  contains  40  per  cent,  of  real  acetic  acid  is,  therefore,  in  the  language  of  the 
Revenue,  35  per  cent,  over  proof;  it  is  the  strongest  acid  on  which  duty  is  charged  by  the 
acetimeter.  In  the  case  of  vinegars  which  have  not  been  distilled,  an  allowance  is  made 
for  the  increase  of  weight  due  to  the  mucilage  present ;  hence,  in  the  acetimeter  sold  by 
Bate,  a  weight,  marked  m,  is  provided,  and  is  used  in  trying  such  vinegars.  As  the  hydrate 
of  lime  employed  causes  the  precipitation  of  part  of  the  mucilaginous  matter  in  the  vine- 
gar, it  serves  to  remove  this  difficulty  to  a  certain  extent.     {Pereira.) — H.  M.  W. 

ACETONE,  SI/71,  pyroacetic  spirit,  mesific  alcohol,  pyroacetic  ether.  C°  H"  0^.  A 
volatile  fluid  usually  obtained  by  the  distillation  of  the  acetates  of  the  alkaline  earths.  It 
is  also  obtained  in  a  variety  of  operations  where  organic  matters  are  exposed  to  high  tem- 
perature. Tartaric  and  citric  acids  yield  it  when  distilled.  Sugar,  gum,  or  starch,  when 
mixed  with  lime  and  distilled,  afford  acetone.  If  crude  acetate  of  lime  be  distilled,  the 
acetone  is  accompanied  by  a  small  quantity  of  ammonia  and  traces  of  methylamine.  The 
latter  is  due  to  the  nitrogen  contained  in  the  wood  ;  the  distillate  from  which  was  used  in 
the  preparation  of  the  acetate  of  lime.  Crude  acetone  may  be  purified  by  redistilling  it  in 
a  water-bath.  A  small  quantity  of  slaked  lime  should  be  added  previous  to  distillation,  to 
combine  with  any  acid  that  may  be  present.  When  pure,  it  forms  a  colorless  mobile  fluid, 
boiling  at  133°  F.  Its  density  at  18°  is  0-7921,  at  32°  it  is  0-8140.  The  density  of  its 
vapor  was  found  by  experiment  to  be  2-00;  theory  requires  2.01,  supposing  six  volumes  of 
carbon  vapor,  twelve  volumes  of  hydrogen,  and  two  volumes  of  oxygen  to  be  condensed 
to  four  volumes.  When  acetone  is  procured  from  acetate  of  lime,  "two  equivalents  of  the 
latter  are  decomposed,  yielding  one  equivalent  of  acetone,  and  two  equivalents  of  car- 
bonate of  lime.  It  has  been  found  that  a  great  number  of  organic  acids,  when  distilled 
under  similar  circumstances,  yield  bodies  bearing  the  same  relation  to  the  parent  acid  that 
acetone  does  to  acetic  acid  :  this  fact  has  caused  the  word  acetone  to  be  used  of  late  in  a 
more  extended  sense  than  formerly.  The  word  ketone  is  now  generally  used  to  express  a 
neutral  substance  derived  by  destructive  distillation  from  an  acid,  the  latter  losing  the 
elements  of  an  equivalent  of  carbonic  acid  during  the  decomposition.  Theoretical  chemista 
are  somewhat  divided  with  regard  to  the  rational  formula  of  the  ketones.  An  overwhelm- 
ing weight  of  evidence  has  been  brought  by  Gerhardt  and  his  followers,  to  prove  that  they 
should  be  regarded  as  aldehydes  in  which  an  equivalent  of  hydrogen  is  replaced  by  the 
•  radical  of  an  alcohol.  Thus  common  acetone  (C*  11"  O'*)  is  aldehyde  (C^  H^  O'*),  ia  which 
one  equivalent  of  hydrogen  is  replaced  by  methyle,  C"  IP. 

Acetone  dissolves  several  gums  and  resins,  amongst  others  sandarach.  Wood  spirit, 
which  sometimes,  owing  to  the  presence  of  impurities,  refuses  to  dissolve  sandarach,  may 
be  made  to  do  so  by  the  addition  of  a  small  quantity  of  acetone. 

When  treated  with  sulphuric  acid  and  distilled,  acetone  yields  a  hydrocarbon  called 
mesitylene  or  mesitvlole,  C"*  II". — C.  G.  W. 

ACETYL.  Two  radicals  are  known  by  this  name,  namely,  C^  IP  and  C*  11'  0".  Their 
nomenclature  has  not,  as  yet,  been  definitely  settled.  Dr.  AVilJiamson  proposes  to  call  it 
othyl.  The  hydrocarbon  C'  H'  is  now  assumed  to  exist  in  aldehyde,  which  can  be  regarded 
as  formed  on  the  typo  two  atoms  of  water,  thus  : — 

In  the  above  formula  we  have  two  atoms  of  water,  in  which  1  equivalent  of  hydrogen  is 
♦  Qu.irterly  Journal  of  Science,  vl,  255.  t  5S  Goo.  III.,  c.  65. 


IG 


ACID. 


replaced  by  the  non-oxidized  radical  C*  H',  -n-hich  may  very  conveniently  be  named  aldylc, 
to  recall  its  existence  in  aldehyde. — C.  G.  W. 

ACID.  {Acidus,  sour,  L.)  The  term  acid  was  formerly  applied  to  bodies  which  were 
sour  to  the  taste,  and  in  popular  language  the  word  is  still  so  used.  It  is  to  be  regretted 
that  the  necessities  of  science  have  led  to  the  extension  of  this  word  to  any  bodies  com- 
bining with  bases  to  form  salts,  whether  such  combining  body  is  sour  or  otherwise.  Had 
not  the  term  acid  been  estabhshed  in  language  as  expressing  a  sour  body,  there  would  have 
been  no  objection  to  its  use  ;  but  chemists  now  apply  the  term  to  substances  which  are  not 
sour,  and  which  do  not  change  blue  vegetable  colors ;  and  consequently  they  fail  to  convey 
a  correct  idea  to  the  popular  mind. 

Hobbes,  in  his  "  Computation  or  Logic,"  says,  "  A  name  is  a  word  taken  at  pleasure  to 
serve  for  a  mark  which  may  raise  in  our  mind  a  thought  like  to  some  thought  we  had 
before,  and  which,  being  pronounced  to  others,  may  be  to  them  a  sign  of  what  thought  the 
speaker  had,  or  had  not,  before  in  his  mind."  This  philosopher  thus  truly  expresses  the 
purpose  of  a  name  ;  and  this  purpose  is  not  fulfilled  by  the  term  acid,  as  now  employed. 

Mr.  John  Stuart  Mill,  in  his  "  System  of  Logic,"  thus,  as  it  appears  not  very  happily, 
endeavors  to  show  that  the  term  acid,  as  a  scientific  term,  is  not  inappropriate  or  incorrect. 

"  Scientific  definitions,  whether  they  are  definitions  of  scientific  terms,  or  of  common 
terms  used  in  a  scientific  sense,  are  almost  always  of  the  kind  last  spoken  of:  their  main 
purpose  is  to  serve  as  the  landmarks  of  scientific  classification.  And,  since  the  classifica- 
tions in  any  science  are  continually  modified  as  scientific  knowledge  advances,  the  defini- 
tions in  the  sciences  are  also  constantly  varying.  A  striking  instance  is  afforded  by  the 
words  acid  and  alkali,  especially  the  former.  As  experimental  discovery  advanced,  the 
substances  classed  with  acids  have  been  constantly  multiplying ;  and,  by  a  natural  conse- 
cjuence,  the  attributes  connoted  by  the  word  have  receded  and  become  fewer.  At  first  it 
connoted  the  attributes  of  combining  with  an  alkali  to  form  a  neutral  substance  (called  a 
salt),  being  compounded  of  a  base  and  oxygen,  causticity  to  the  taste  and  touch,  fluidity, 
&c.  The  true  analysis  of  muriatic  acid  into  chlorine  and  hydrogen  caused  the  second 
property,  composition  from  a  base  and  oxygen,  to  be  excluded  from  the  connotation.  The 
same  discovery  fixed  the  attention  of  chemists  upon  hydrogen  as  an  important  element  in 
acids ;  and  more  recent  discoveries  having  led  to  the  recognition  of  its  presence  in  sul- 
phuric, nitric,  and  many  other  acids,  where  its  existence  was  not  previously  suspected,  there 
is  now  a  tendency  to  include  the  presence  of  this  element  in  the  connotation  of  the  word. 
But  carbonic  acid,  silica,  sulphurous  acid,  have  no  hydrogen  in  their  composition ;  that 
property  cannot,  therefore,  be  connoted  by  the  term,  unless  those  substances  are  no  longer 
to  be  considered  acids.  Causticity  and  fluidity  have  long  since  been  excluded^  from  the 
characteristics  of  the  class  by  the  inclusion  of  silica  and  many  other  substances  in  it ;  and 
the  formation  of  neutr.il  bodies  by  combination  with  alkalis,  together  with  such  electro- 
chemical peculiarities  as  this  is  supposed  to  impl}-,  are  now  the  only  differentia  which  form 
the  fixed  connotation  of  the  word  acid  as  a  term  of  chemical  science." 

The  term  Alkali,  though  it  is  included  by  Mr.  J.  S.  Mill  in  connection  with  acid  in  his 
remarks,  does  not  stand,  even  as  a  scientific  term,  in  the  objectional  position  in  which  we 
find  acid.  Alkali  is  not,  strictly  speaking,  a  common  name  to  which  any  definite  idea  is 
attached.  Acid,  on  the  contrary,  is  a  word  coimuonlif  employed  to  signify  sour.  "With  the 
immense  increase  which  organic"  chemistry  has  given  to  the  number  of  acids,  it  does  appear 
necessary,  to  avoid  confusion,  that  some  new  arrangement,  based  on  a  strictly  logical  plan, 
shouhl  be  adopted.  This  is,  however,  a  task  for  a  master  mind ;  and  possibly  we  must  wait 
for  another  generation  before  such  a  mind  appears  among  us. 

In  this  Dictionary  all  the  acids  named  will  be  found  under  their  respective  heads ;  as 
Acetic,  Nitric,  Sclpiicric  Acids,  &c. 

ACIDIFIER.  Any  simple  or  compound  body  whose  presence  is  necessary  for  the  pro- 
duction of  an  acid ;  as  oxvgen,  chlorine,  bromine,  iodine,  fluorine,  sulphur,  kc,  &c. 

ACIDIMETER.  An  instrument  for  measuring  the  strength  or  quantity  of  real  acid- 
contained  in  a  free  state  in  liquids.  The  construction  of  that  instrument  is  founded  on  the 
principle  that  the  quantitv  of  real  acid  present  in  any  sample  is  proportional  to  the  quan- 
tity of  alkali  which  a  given  weight  of  it  can  neutralize.  The  instrument,  like  the  alkalim- 
etcr  (see  Alkalimeter),  is  made  to  contain  1,000  grains  in  weight  of  pure  distilled  water, 
and  is  divided  accurately  into  100  divisions,  each  of  which  therefore  represents  10  grains 
of  pure  distilled  water  ;  but  as  the  specific  gravity  of  the  liquids  which  it  serves  to  measure 
may  be  heavier  or  lighter  than  pure  water,  100  divisions  of  such  liquids  are  often  called 
1,000  grains'  measure,  irrespectively  of  their  weight  (specific  gravity),  and  accordingly 
10-20,  &c.  divisions  of  the  acidimeter  are  spoken  of  as  100-200,  &c.  grains'  measure ;_  that 
is  to  say,  as  a  quantity  or  measure  which,  if  filled  with  pure  water,  would  have  weighed 
that  number  of  grains. 

ACIDIMETRY.  Acidimetry  is  the  name  of  a  chemical  process  of  analysis  by  means 
of  which  the  strength  of  acids-^that  is  to  say,  the  quantity  of  pure  free  acid  contained  in 
a  liquid — can  be  ascertained  or  estimated.     The  principle  of  the  method  is  based  upon  Dal- 


AOIDIMETRY.  17 

ton's  law  of  chemical  combinations ;  or,  in  other  words,  upon  the  fact  that,  in  otdev  to  pro- 
duce a  complete  reaction,  a  certain  definite  weight  of  reagent  is  required. 

If,  for  example,  we  take  1  equivalent,  or  49  parts  in  weight,  of  pure  oil  of  vitriol  of 
specific  gravity  1-8485,  dilute  it  (of  course  within  limits)  with  no  matter  what  quantity  of 
water,  and  add  thereto  either  soda,  potash,  magnesia,  ammonia,  or  their  carbonates,  or  in 
lact  any  other  base,  until  the  acid  is  neutralized — that  is  to  say,  until  blue  litmus-paper  is 
no  lono-er,  or  only  very  faintly,  reddened  when  moistened  with  a  drop  of  the  acid  liquid 
under  examination, — it  will  be  found  that  the  respective  weights  of  each  base  required  to 
produce  that  effect  will  greatly  differ,  and  that  with  respect  to  the  bases  just  mentioned 
these  weights  will  be  as  follows  : — 

Soda  (caustic)  1  equiv.  =  31  parts  in  weight^   Saturate    or    neutralize    1 
Potash  (caustic)        "       =  47  "  j        eqv.  =  49  parts  in  weight 

Ammonia  "      =17  "  J-      of  pure  oil  of  vitriol  (sp. 

Carbonate  of  soda    "      =  53  "  '         gr.  1-8485),  or  1  equiv. 

Carbonate  of  potash  "       =69  "  J        of  any  other  acid. 

This  being  the  case,  it  is  evident  that  if  we  wish  to  ascertain  by  such  a  method  the  quantity 
of  sulphuric  acid  or  of  any  other  acid  contained  in  a  liquid,  it  will  be  necessary,  on  the  one 
hand,  to  weigh  or  measure  accurately  a  given  quantity  of  that  liquid  to  be  examined,  and, 
on  the  other  hand,  to  dissolve  in  a  known  volume  of  water  the  iccight  above  mentioned  of 
any  one  of  the  bases  just  alluded  to,  and  to  pour  that  solution  gradually  into  that  of^the 
acid  until  neutralization  is  obtained ;  the  number  of  volumes  of  the  basic  solution  which 
will  have  been  required  for  the  purpose  will  evidently  indicate  the  amount  in  weight  of 
acid  which  existed  in  the  liquid  under  examination.  Acidimetry  is  therefore  exactly  the 
reverse  of  alkalimetry,  since  in  principle  it  depends  on  the  number  of  volumes  of  a  solu- 
tion of  a  base  diluted  with  water  to  a  definite  strength,  which  are  required  to  neutralize  a 
known  weight  or  measure  of  the  different  samples  of  acids. 

The  solution  containing  the  knoivn  weight  of  base,  and  capable  therefore  of  saturating 
a  knoicn  weight  of  acid,  is  called  a  "  test-liquor;"  and  an  aqueous  solution  of  ammonia,  of 
a  standard  strength,  as  first  proposed  by  Dr.  Urc,  affords  a  most  exact  and  convenient 
means  of  effecting  the  purpose,  when  gradually  poured  from  a  graduated  droi)ping-tube  or 
acidimeter  into  the  sample  of  acid  to  be  examined. 

The  strength  of  the  water  of  ammonia  used  for  the  experiment  should  be  so  adjusted 
that  1,000  grains'  measure  of  it  (that  is,  100  divisions  of  the  alkalimeter)  really  contain  one 
equivalent  (17  grains)  of  ammonia,  and  consequently  neutralize  one  equivalent  of  any  one 
real  acid.  The  specific  gravity  of  the  pure  water  of  ammonia  employed  as  a  test  for  that 
purpose  should  be  exactly  0*992,  and  when  so  adjusted,  1,000  grains'  measure  (100  divisions 
of  the  acidimeter)  will  then  neutralize  exactly 

40  grains,  or  one  equivalent,  of  sulphuric  acid  (dry). 
49  "  "  "  oil  of  vitriol,  sp.  gr.  1.8485. 

37.5       "  "  "  hydrochloric  acid  (gas,  dry). 

54  "  "  "  nitric  acid  (dry). 

60  "  "  "  crystallized  acetic  acid. 

45  "  "  "  oxalic  acid. 

150  "  "  "  tartaric  acid. 

51  "  "  "  acetic  acid. 

And  so  forth  with  the  other  acids. 

A  standard  liquor  of  ammonia  of  that  strength  becomes,  therefore,  a  universal  acid- 
imeter, since  the  number  of  measures  or  divisions  used  to  effect  the  neutralization  of  10  or 
of  100  grains  of  any  one  acid,  being  multiplied  by  the  atomic  weight  or  equivalent  number 
of  the  acid  under  examination,  the  product,  divided  by  10  or  by  100,  will  indicate  the  per- 
centage of  real  acid  contained  in  the  sample ;  the  proportion  of  free  acid  being  thus 
determined  with  precision,  even  to  -^^  of  a  grain,  in  the  course  of  five  minutes,  as  will  be 
shown  presently. 

The  most  convenient  method  of  preparing  the  standard  liquor  of  ammonia  of  that 
specific  gravity  is  by  means  of  a  glass  bead,  not  but  that  specific  gravity  bottles  and 
hydrometers  may,  of  course,  be  emploj'od ;  but  Dr.  Ure  remarks,  with  reason,  that  they 
furnish  incomparably  more  tedious  and  less  delicate  means  of  adjustment.  The  glass  bead, 
of  the  gravity  which  the  test-liquor  of  ammonia  should-  have,  floats,  of  course,  in  the 
middle  of  such  a  liquor,  at  the  temperature  of  60°  F.  ;  but  if  the  strength  of  the  liquor 
becomes  attenuated  by  evaporation,  or  its  temperature  increased,  the  attention  of  the 
operator  is  immediately  called  to  the  fact,  since  the  difference  of  a  single  degree  of  heat,  or 
the  loss  of  a  single  hundredth  part  of  a  grain  of  ammonia  per  cent.,  will  cause  the  bead  to 
sink  to  the  bottom — a  degree  of  precision  which  no  hydrometer  can  rival,  and  which  could 
not  otherwise  be  obtained,  except  by  the  troublesome  operation  of  accurate  weighing. 
Whether  the  solution  remains  uniform  in  strength  is  best  ascertained  by  introducing  into 
the  bottle  containing  the  ammonia  test-liquor  two  glass  beads,  so  adjusted  that  one,  being 

Vol.  III.— 2 


18 


AOIDIMETRY. 


very  sli"-htly  heavier  than  the  liquid,  may  remain  at  the  bottom ;  whilst  the  other,  being 
very  slightly  lighter,  reaches  the  top,  and  remains  just  under  the  surface  as  long  as  the 
liquor  is  in  the  normal  state ;  but  when,  by  the  evaporation  of  some  ammonia,  the  liquor 
becomes  weaker,  and  consequently  its  specific  gravity  greater,  the  bead  at  the  bottom  rises 
towards  the  surface,  in  which  case  a  few  drops  of  strong  ammonia  should  be  added  to 
restore  the  balance. 

An  aqueous  solution  of  ammonia,  of  the  above  strength  and  gravity,  being  prepared,  the 
acidimetrical  process  is  in  every  way  similar  to  that  practised  in  alkalimetry ;  that  is  to  say, 
a  known  weight,  for  example,  10  or  100  grains  of  the  sample  of  acid  to  be  examined  are 
poured  into  a  sufBciently  large  glass  vessel,  and  diluted,  if  need  be,  with  water,  and  a  little 
tincture  of  litmus  is  poured  into  it,  in  order  to  impart  a  distinct  red  color  to  it ;  100 
divisions  or  1,000  grains'  measure,  of  the  standard  ammonia  test-liquor  above  alluded  to, 
are  then  poured  into  an  alkalimcter  (which,  in  the  present  case,  is  used  as  an  acidimetcr), 
and  the  operator  proceeds  to  pour  the  ammonia  test-liquor  from  the  alkalimeter  into  the 
vessel  containing  the  acid  under  examination,  in  the  same  manner,  and  with  the  same 
precautions  used  in  alkalimetry  (see  Alkalimetry),  until  the  change  of  color,  from  red  to 
blue,  of  the  acid  liquor  in  the  vessel  indicates  that  the  neutralization  is  complete,  and  the 
operation  finished. 

Let  us  suppose  that  100  grains  in  weight  of  a  sample  of  sulphuric  acid,  for  example, 
have  required  61  divisions  (010  water-grains'  measure)  of  the  acidimetcr  for  their  complete 
neutralization,  since  100  divisions  (that  is  to  say,  a  whole  acidimetcr  full)  of  the  test-liquor 
of  ammonia  are  capable  of  neutralizing  exactly  49  grains — one  equivalent — of  oil  of  vitriol, 
of  specific  gravity,  1-8485,  it  is  clear  that  the  61  divisions  employed  will  have  neutralized 
29-89  of  that  acid,  and,  consequently,  the  sample  of  sulphuric  acid  examined  contained  that 
quantity  per  cent,  of  pure  oil  of  vitriol,  representing  24-4  per  cent,  of  pure  anhydrous 
sulphuric  acid :  thus — 

Divisions.       Oil  of  Vitriol. 

100        :        49       ::       01        :        x     =     29-89. 

Anhydrous  Acid. 
100        :        40       ::       61        :        z      =     24-4. 
The  specific  gravity  of  an  acid  of  that  strength  is  1-2178. 

In  the  same  manner,  suppose  that  100  grains  in  weight  of  hydrochloric  acid  have 
required  90  divisions  (900  grains'  measure)  of  the  acidimetcr  for  their  complete  neutraliza- 
tion, the  equivalent  of  dry  hydrochloric  acid  gas  being  SO-5,  it  is  clear  that  since  90  divisions 
only  of  the  ammonia  test-liquor  have  been  employed,  the  sample  operated  upon  must  have 
contained  per  cent,  a  quantity  of  acid  equal  to  33-30  of  dry  hydrochloric  acid  gas  in  solution, 
as  shown  by  the  proportion  : — 

Divis.       Ilydrochloric  acid. 
100      :  30-5         ::         90      :      a;     =     32-85. 

The  specific  gravity  of  such  a  sample  would  be  1-1646. 

Instead  of  the  ammonia  test-liquor  just  alluded  to,  it  is  clear  that  a  solution  containing 
one  cciuivalent  of  any  other  base — such  as,  for  example,  carbonate  of  soda,  or  carbonate  of 
potash,  caustic  lime,  &c. — may  be  used  for  the  purpose  of  neutralizing  the  acid  under 
examination.  The  quantity  of  these  salts  required  for  saturation  will  of  course  indicate  the 
quantity  of  real  acid,  and,  by  calculation,  the  percentage  thereof  in  the  sample,  thus  : — The 
equivalent  of  pure  carbonate  of  soda  53,  and  that  of  carbonate  of  potash  69,  either  of  these 
weights  will  represent  one  equivalent,  and  consequently  49  grains  of  pure  oil  of  vitriol,  36-5 
of  dry  hydrochloric  acid,  60  of  crystallized,  or  51  of  anhydrous  acetic  acid,  and  so  on.  The 
acidimetrical  assay  is  performed  as  follows  : — 

If  with  carbonate  of  soda,  take  530  grains  of  pure  and  dry  carbonate  of  soda,  obtained 
l)y  igniting  tlie  bicarbonate  of  that  base  (see  Alkalimetry),  and  dissolve  them  in  10,000 
water  grains'  measure  (1,000  acidimetrical  divisions)  of  distilled  water.  It  is  evident  that 
each  acidimetcr  full  (100  divisions)  of  such  a  solution  will  then  correspond  to  one  equivalent 
of  any  acid ;  and  accordingly,  if  the  test-liquor  of  carbonate  of  soda  be  poured  from  the 
acidimetcr  into  a  weighed  quantity  of  any  acid,  with  the  same  precautions  as  before,  until 
the  neutralization  is  complete,  the  number  of  divisions  employed  in  the  operation  will,  by 
simple  rule  of  proportion,  indicate  the  quantity  of  acid  present  in  the  sample  as  before. 
Pure  carbonate  of  soda  is  easily-  obtained  by  recrystallizing  once  or  twice  the  crystals  of 
carbonate  of  soda  of  commerce,  and  carefully  wasliing  them.  By  heating  them  gradually 
they  melt,  and  at  a  very  low  red  heat  entirely  lose  their  water  of  crystallization  and  become 
converted  into  pulverulent  anhydrous  neutral  carbonate  of  soda,  which  should  be  kept  in 
well  closed  bottles. 

When  carbonrtic  of  pofaxh  is  used,  then,  since  the  equivalent  of  carbonate  of  potash  is 
69,  the  operator  should  dissolve  690  grains  of  it  in  the  10,000  grains  of  pure  distilled  water, 
and  the  acidimetcr  being  now  filled  with  this  test-liquor,  the  assay  is  carried  on  again 
precisely  in  the  same  manner  as  before.     Neutral  carbonate  of  potash  for  acidimetrical  use 


ACIDIMETRY.  '  19 

is  prepared  by  heating  the  bicarbonate  of  that  base  to  redness,  in  order  to  expel  one 
equivalent  of  its  carbonic  acid  ;  the  residue  left  is  pure  neutral  carbonate  of  potash  ;  and  in 
order  to  prevent  its  absorbing  moisture,  it  should  be  put,  whilst  still  hot,  on  a  slab  placed 
over  concentrated  sulphuric  acid,  or  chloride  of  calcium,  under  a  glass  bell,  and,  when 
sufficiently  cool  to  be  handled,  transferred  to  bottles  carefully  closed. 

To  adapt  the  above  methods  to  the  French  weights  and  measures,  now  used  also  gener- 
ally by  the  German  chemist,  we  need  only  substitute  100  decigrammes  for  100  grains,  and 
proceed  with  the  graduation  as  already  described. 

A  solution  of  caustic  lime  in  cane  sugar  has  likewise  been  proposed  by  M.  Peligot  for 
acidimetrical  purposes.  To  prepare  such  a  solution,  take  pure  caustic  lime,  obtained  by 
heating  Carara  marble  among  charcoal  in  a  furnace  ;  when  sufficiently  roasted  to  convert  it 
into  quicklime,  slake  it  witli  water,  and  pour  upon  the  slaked  lime  as  much  water  as  is 
necessary  to  produce  a  milky  liquor ;  put  this  milky  liquor  in  a  bottle,  and  add  thereto,  in 
the  cold,  a  certain  quantity  of  pulverized  sugar-candy ;  close  the  bottle  with  a  good  cork, 
and  shake  the  whole  mass  well.  After  a  certain  time  it  will  be  observed  that  the  milky 
liquid  has  become  very  much  clearer,  and  perhaps  quite  hmpid ;  filter  it,  and  the  filtrate 
will  be  found  to  contain  about  50  parts  of  lime  for  every  100  of  sugar  employed.  The  liquor 
should  not  be  heated,  because  saccharate  of  lime  is  much  more  soluble  in  cold  than  in  hot 
water,  and  if  heat  were  applied  it  would  become  turbid  or  thick,  though  on  cooling  it  would 
become  clear  again.* 

A  concentrated  solution  of  lime  in  sugar  being  thus  obtained,  it  should  now  be  diluted 
to  such  a  degree  that  1,000  water  grains'  measure  of  it  may  be  capable  of  saturating  exactly 
one  equivalent  of  ajiy  acid,  which  is  done  as  follows  : — Take  100  grains  of  hydrochloric  acid 
of  specific  gravity  1-1812,  that  weight  of  acid  contains  exactly  one  equivalent  =  36-5  of 
pure  hydrochloric  acid  gas ;  on  the  other  hand,  fill  the  acidimeter  up  to  0  (zero)  with  the 
solution  of  caustic  lime  in  sugar  prepared  as  abovesaid,  and  pour  the  contents  into  the  acid 
until  exact  neutralization  is  obtained,  which  is  known  by  testing  with  litmus  paper  in  the 
usual  manner  already  described.  If  the  whole  of  the  100  divisions  of  the  acidimeter  had 
been  required  exactly  to  neutralize  the  100  grains'  weight  of  hydrochloric  acid  of  the  specific 
gravity  mentioned,  it  would  have  been  a  proof  that  it  was  of  the  right  strength  ;  but  suppose, 
on  the  contrary,  that  only  50  divisions  of  the  lime  solution  in  the  acidimeter  have  been 
sufficient  for  the  purpose,  it  is  evident  that  it  is  half  too  strong,  or,  in  other  words,  one 
equivalent  of  lime  (  =  28)  is  contained  in  those  50  divisions  instead  of  in  100.  Pour,  there- 
fore, at  once,  50  divisions  or  measures  of  that  lime-liquor  into  a  glass  cylinder  accurately 
divided  into  100  divisions,  and  fill  up  the  remaining  5(5  divisions  with  water;  stir  the  whole 
well,  and  100  divisions  of  the  lime-liquor  will,  of  course,  now  contain  as  much  lime  as  was 
contained  before  in  the  50 ;  or,  in  other  words,  100  acidimetrical  divisions  will  now  contain 
1  equivalent  of  lime,  and  therefore  yill  be  capable  of  exactly  neutralizing  1  equivalent  of 
any  acid. 

When,  however,  saccharate  of  lime  is  used  for  the  determination  of  sulphuric  acid,  it  is 
necessary  to  dilute  it  considerably,  for  otherwise  a  precipitate  of  sulphate  of  lime  would  be 
produced.  This  reagent,  moreover,  is  evidently  applicable  only  to  the  determination  of  such 
acids  the  lime  salts  of  which  are  soluble  in  water. 

Instead  of  a  solution  of  caustic  lime  in  sugar,  a  clean  dry  piece  of  white  Carara  marble 
may  be  used.  >Suppose,  for  example,  that  the  acid  to  be  assayed  is  acetic  acid,  the  instruc- 
tions given  by  Brande  are  as  follows : — A  clean  dry  piece  of  marble  is  selected  and  accu- 
rately weighed  ;  it  is  then  suspended  by  a  silk  thread  into  a  known  quantity  of  the  vinegar 
or  acetic  acid  to  be  examined,  and  which  is  cautiously  stirred  with  a  glass  rod,  so  as  to  mix 
its  parts,  but  without  detaching  any  splinters  from  the  weighed  marble,  till  the  whole  of  the 
acid  is  saturated,  and  no  further  action  on  the  marble  is  observed.  The  marble  is  then  tal^en 
out,  washed  with  distilled  water,  and  weighed ;  the  loss  in  weight  which  it  has  sustained 
may  be  considered  as  equal  to  the  quantity  of  acetic  acid  present,  since  the  atomic  weight  of 
carbonate  of  lime  (  =  50)  is  very  nearly  the  same  as  that  of  acetic  acid  (  =  51").  Such  a 
process,  however,  is  obviously  less  exact  than  those  already  described. 

But  whichever  base  is  employed  to  prepare  the  test-liquor,  it  is  clear  that  the  acid  tested 
with  it  must  be  so  far  pure  as  not  to  contain  any  other  free  acid  than  that  for  which  it  is 
tested,  for  in  that  case  the  results  arrived  at  would  be  perfiictly  fallacious.  Unless,  therefore, 
the  operator  has  reason  to  know  that  the  acid,  the  strength  of  which  has  to  be  examined  by 
that  process,  is  genuine  of  its  kind,  he  must  make  a  qualitative  analysis  to  satisfy  himself 
that  it  is  so  ;  for  in  the  contrary  case  the  acid  would  not  be  in  a  fit  state  to  be  submitted  to 
an  acidimetrical  as.say. 

We  shall  terminate  this  article  by  a  description  of  Liebig's  acidimetrical  method  of 
determining  tlie  amount  of  prussic  acid  contained  in  solutions ;  for  example,  in  medicinal 
prussic  acid,  in  laurel  and  liitter  almond  water,  essence  of  bitter  almonds,  and  cyanide  of 
potassium.     The  process  is  based  upon  the  following  reaction  : — When  an  excess  of  caustic 

*  The  directions  friven  by  M.  Violotto  for  the  preparation  of  Sarcharnte  of  Limo  are  as  follows: — 
Digest  in  the  cold  50  grammes  of  slaked  caustic  lime  in  1  litre  of  water  containing  100  grammes  of  sugar. 


I 


20 


ACIPENSER. 


potash  is  poured  in  a  solution  which  contains  prussic  acid,  cyanide  of  potassium  is,  of 
course  formed  •  and  if  nitrate  of  silver  be  then  poured  in  such  a  liquor,  a  precipitate  of 
cvanid'e  of  silver  is  produced,  but  it  is  immediately  redissolved  by  shaking,  because  a  double 
cyanide  of  silver  and  of  potassium  (Ag  Cj  -{- K  Cy)  is  formed,  which  dissolves,  v,-itbout 
alteration,  in  the  excess  of  potash  employed.  The  addition  of  a  fresh  quantity  of  nitrate  of 
silver  produces  again  a  precipitate  which  agitation  causes  to  disappear  as  before ;  and  this 
reaction  goes  on  until  half  the  amount  of  prussic  acid  present  in  the  liquor  has  been  taken 
up  to  produce  cyanide  of  silver,  the  other  half  being  engaged  with  the  potassium  in  the 
formation  of  a  double  cyanide  of  silver  and  of  potassium,  as  just  said.  As  soon,  however, 
as  this  point  is  reached,  any  new  quantity  of  nitrate  of  silver  poured  in  the  liquor  causes 
the  cyanide  of  potassium  to  react  upon  the  silver  of  the  nitrate,  to  produce  a  permanent 
precipitate  of  cyanide  of  silver,  which  indicates  that  the  reaction  is  complete,  and  that  the 
assay  is  terminated.  The  presence  of  chlorides,  far  from  interfering,  is  desirable,  and  a 
certain  quantity  of  common  salt  is  accordingly  added,  the  reaction  of  chloride  of  silver  being 
analogous  to  that  of  the  cyanide  of  the  same  metal. 

To  determine  the  strength  of  prussic  acid  according  to  the  above  process,  a  test  or  normal 
solution  should  be  first  prepared,  which  is  as  follows  : — 

Since  1  equivalent  of  nitrate  of  silver  (  =  170)  represents,  as  we  have  seen,  2  equivalents 
of  prussic  acid  (  =  54),  dissolve,  therefore,  170  grains  of  pure  fused  nitrate  of  silver  in 
10  000  water-grains'  measure  of  pure  water;  1,000  water-grains'  measure  (1  acidimeter  full) 
of  such  solution  will  therefore  represent  5'4  grains  of  prussic  acid ;  and  consequently  each 
acidimetrical  division  0-054  grain  of  pure  prussic  acid. 

Take  now  a  given  weight  or  measure  of  the  sample  of  prussic  acid,  or  cyanide  of  potas- 
sium, or  laurel,  or  bitter-almond  water,  or  essence  of  bitter  almonds ;  dilute  it  with  three  or 
four  times  its  volume  of  water,  add  caustic  potash  until  the  whole  is  rendered  alkaline,  and 
carefully  pour  into  it  a  certain  quantity  of  the  normal  silver  solution  from  the  acidimeter, 
until  a  slight  precipitate  begins  to  appear  which  cannot  be  redissolved  by  agitation  ;  observe 
the  number  of  acidimetrical  divisions  of  the  test  silver  solution  employed,  and  that  number 
multiplied  by  0-054  will,  of  course,  indicate  the  proportion  of  prussic  acid  present  in  the 
quantity  of  the  sample  operated  upon. 

For  such  liquids  which,  like  laurel  water,  contain  very  little  prussic  acid,  it  is  advisable 
to  dilute  the  test  silver  liquor  with  nine  times  its  bulk  of  water ;  a  decimal  solution  is  thus 
obtained,  each  acidimetrical  division  of  which  will  only  represent  0-0054  of  prussic  acid,  by 
which  figure  the  number  of  divisions  employed  should  then  be  multiplied. 

As  the  essence  of  bitter  almonds  mixed  with  water  is  turbid,  it  is  absolutely  necessary  to 
add  and  shake  it  with  a  sufficient  quantity  of  water  to  dissolve  the  particles  of  oil  to  which 
the  milkiness  is  due,  and  render  it  quite  clear. 

Instead  of  an  acidimeter,  an  ordinary  balance  may  \je  used,  as  follows  : — Take  63  grains 
of  fused  nitrate  of  silver,  and  dissolve  them  in  5,937  grains'  weight  of  pure  distilled  water, 
makin"-  alto"-ether  6,000  grains'  weight  of  test  silver  solution.  Weigh  off  now  in  a  beaker 
any  quantity,  say  100,  or,  if  very  -n-eak,  1,000  grains'  weight  of  the  sample  of  prussic  acid 
to  be  examined,  dilute  it  with  three  or  four  times  its  bulk  of  water,  mix  with  it  a  certain 
quantity  of  a  solution  of  common  salt,  and  a  few  drops  of  caustic  potash  over  and  above  the 
quantity  necessary  to  make  it  alkaline.  Pour  now  carefully  into  the  liquid  so  prepared  a 
portion  of  the  test  solution  of  silver  alluded  to,  until  a  turbidness  or  milkiness  begins  to  bo 
formed,  which  does  not  disappear  by  agitation,  and  which  indicates  that  the  reaction  is 
complete.  Every  300  grains  of  the  test  silver  solution  employed  represent  1  grain's  weight 
of  pure  anhvdrous  prussic  acid.  _ 

The  rationale  of  these  numbers  is  evident :  since  1  cquiv.  =  170  of  nitrate  of  silver 
corresponds  to  2  equiv.  =  54  of  prussic  acid ;  G3  of  nitrate  of  silver  correspond  to  20  of 
prussic  acid,  and  consequently  300  of  a  solution  containing  63  of  nitrate  of  silver  in  6,000 
correspond  to  1  of  prussic  acid,  thus  : — 

170    :    54   ::      03      :      20 
6,000    :    20   ::    300      :      1 
Lastly,  the  strength  of  prussic  acid  may  also  be  determined  with  an  ordinary  balance  by 
a  method  proposed  by  Dr.  Ure,  which  method,  however,  is  much  less  convenient  than  that 
of  Liebig ;  it  consists  in  adding  peroxide  of  mercury,  in  fine  powder,  to  the  liquor  which 
contains°prussic  acid,  until  it  ceases  to  be  dissolved.     As  the  equivalent  of  peroxide  of 
miTcury  =  108,  is  exactly  four  times  that  of  prussic  acid  =  27,  the  weight  of  peroxide  of 
mercury  employed  divided  by  four  will  give  the  quantity  of  prussic  acid  present.  —A.  N. 
ACIPENSER.     See  Isinglass. 

ACONITINE.  C"^"  II"  NO".  A  poisonous  alkaloid  constituting  the  active  prmciple  of 
the  Aconite,  Aconitwn  Knpellus. — C.  G.  W. 

ACORNS.  The  seed  of  the  oak  {quercus).  These  possess  some  of  the  properties  of  the 
bark  •,  but  in  a  very  diluted  degree.  Acorns  are  now  rarely  used.  Pigs  are  sometimes  fed 
upon  them.     308  bushels  were  imported  in  1855. 


ADHESION. 


21 


ACORUS  CALAMUS.  The  common  sweet  flag.  This  plaut  is  a  native  of  Enghind, ' 
growiiK'  abundantly  in  the  rivers  of  Norfolk ;  from  which  county  the  London  market  is 
chiefly 'supplied.  The  radix  calami  aromatici  of  the  shops  occurs  in  flattened  pieces  about 
one  inch  wide  and  four  or  five  inches  long.  It  is  employed  medicinally  as  an  aromatic,  and 
it  is  said  to  be  used  by  some  distillers  to  flavor  gin.  The  essential  oil  {oleum  acori  calami) 
of  the  sweet  fla^  is  used  by  snutf-makers  for  scenting  snufl",  and  it  sometimes  enters  as  one 
of  the  aromatic^ingredients  of  aromatic  vinegar. — Pereira. 

ACROSPIRE.  {Plumule,  Fr. ;  Blattkeim,  Germ.)  The  sprout  at  the  end  of  seeds 
when  thev  bcnn  to  germinate.  The  name  is  derived  from  two  Greek  words,  signifying 
highest  and  spire,  and  has  been  adopted  on  account  of  its  spiral  form.  It  is  the  plume  or 
plumule  of  modern  botanists.  Malsters  use  the  name  to  express  the  growing  of  the  barley. 
"  The  first  leaves  that  appear  when  corn  sprouts." — Lindley. 

ACRYL AMINE  or  ALLYL AMINE.  (C  H'  N.)  A  new  alkaloid  obtained  by  Hoff- 
mann and  Cahorns,  by  boiling  cyanate  of  allyle  with  a  strong  solution  of  potash.  It  boils  at 
about  365°.— C.  G.  W. 

ACTINISM.  (From  d/crlv,  a  ray ;  signifying  merely  the  pmcer  of  a  ray,  -without  defining 
what  character  of  ray  is  intended. ) 

As  early  as  1812,  M.  Berard  (in  a  communication  to  the  Academy  of  Sciences,  on  some 
observations  made  by  him  of  the  phenomena  of  solar  action)  drew  attention  to  the  fact  that 
three  very  distinct  sets  of  physical  powers  were  manifested.  Luminous  power,  Heat-produc- 
ing power,  and  Chemical  power. 

The  actual  conditions  of  the  sun-beam  will  be  understood  by  reference  to  the  annexed 
woodcut,  and  attention  to  the  following  description.  Jig.  i:  a  b  represents  the  prismatic 
spectrum — as  obtained  by  the  decomposition  of  white 

light  by  the  prism — or  Newtonian  luminous  spectrum,  4  5 

consisting  of  certain  bands  of  color.  Newton  deter- 
mined those  rays  to  lie  seven  in  number  ;  red,  orange, 
yellow,  green,  blue,  indigo,  and  violet ;  recent  re- 
searches, by  Sir  John  Herschel  and  others,  have  proved 
the  existence  of  two  other  rays  ;  one,  the  extreme  red 
or  crimson  ray  c,  found  at  the  least  refrangible  end  of 
the  spectrum,  the  other  occurring  at  the  most  frangible 
end,  or  beyond  the  violet  rays,  which  is  a  lavender  or 
gray  ray.  Beyond  this  point  up  to/.  Professor  Stokes 
has  discovered  a  new  set  of  rays,  which  are  only  brought 
into  view  when  the  light  is  received  upon  ihe  surfaces 
of  bodies  which  possess  the  property  of  altering  the 
refrangibility  of  the  rays.  Those  rays  have  been  called 
the  fluorescent  rays,  from  the  circumstance  that  some 
of  the  varieties  of  Fluor  Spar  exhibit  this  phenomenon 
in  a  remarkable  manner.  In  the  engraving  {fig.  4,)  the 
curved  line  l  from  a  to  c  indicates  the  full  extent  of 
the  luminous  spectrum,  the  point  marked  l  showing 
the  maximum  of  illuminating  power,  which  exists  in 
the  yellow  ray. 

Sir  William  Herschel  and  Sir  Henry  Englefield  de- 
termined, in  the  first  instance,  the  maximum  point  for 
the  calorific  rays,  and  Sir  John  Herschel  subsequently 
confirmed  their  results,  proving  that  the  greatest  heat 
was  found  below  the  red  ray,  and  that  it  gradually 
diminished  in  power  with  the  increase  of  refrangibility 
in  the  rays,  ceasing  entirely  in  the  violet  ray.  Heat 
rays  have  been  detected  down  to  the  point  </,  and  the 
curved  line  n  indicates  -the  extent  of  their  action. 

Now,  if  any  substance  capable  of  undergoing  chemical  change  bo  exposed  to  this  spec- 
trum, the  result  will  be  found  to  be  such  as  is  represented  in  the  accompanying  figure  and 
fig.  5.  Over  the  space  upon  which  the  greatest  amount  of  light  falls,  i.  c.  the  region  of 
the  yellow  and  orange  rays  l,  no  chemical  change  is  effected  :  by  prolonged  action  a  slight 
change  is  brought  about  where  the  red  ray  falls,  r,  but  from  the  mean  green  ray  g  uj)  to 
the  point  /,  a  certain  amount  of  chemical  action  is  maintained  ;  the  maximum  of  action 
being  in  the  blue  and  violet  rays  a.  Thus  the  curve  line  (fig.  4)  from  e  to  /  represents 
the  extent  and  degree  of  chemical  power  as  manifested  in  the  solar  spectrum.  Two 
maxima  are  marked  a  a,  differing  widely  however  in  their  degree. 

ADHESION  {sticking  together).  The  union  of  two  surfaces.  With  the  phenomena 
which  are  dependent  upon  bringing  two  surfaces  so  closely  together  that  the  influence  of 
cohesion  is  exerted,  we  have  not  to  de^l.  In  arts  and  manufactures,  adhesion  is  effected  by 
interposing  between  the  surfaces  to  be  united,  some  body  possessing  peculiar  properties, 


22 


ADIPOSE  SU15STAN0E  ob  ADIPOSE  TISSUE. 


'such  as  gum,  plaster,  resin,  marine  or  ordinary  glue,  and  various  kinds  of  cement.  (See 
those  articles.)  In  many  treatises,  there  has  been  a  sad  confusion  between  tlie  terms 
adhesion  and  cohesiort.  It  is  to  be  regretted  that  our  literature  shows  a  growing  careless- 
ness in  this  respect.  Adhesion  should  be  restricted  to  mean,  sticking  together  by  means 
of  some  interposed  substance;  co/iesion,  the  state  of  union  eflected  by  natural  attraction. 

Not  only  is  adhesion  exhibited  in  works  of  art  or  manufacture,  we  find  it  very  strikingly 
exhibited  in  nature.  Fragments  of  rocks  which  have  been  shattered  by  convulsion  are 
found  to  be  cemented  together  by  silica,  lime,  oxide  of  iron,  and  the  like.  We  sometimes 
find  portions  of  stone  cemented  together  by  the  ores  of  the  metals ;  and,  again,  broken 
parts  of  mineral  lodes  are  frequently  reunited  bv  the  earthy  minerals. 

ADIPOSE  SUBSTANCE  or  ADIPOSE  TISSUE.  {Tissu  graissevx,  Fr.)  An  animal 
oil,  resembling  in  its  essential  properties  the  vegetable  oils.  During  life,  it  appears  to  exist 
in  a  fluid  or  semi-fluid  state ;  but  in  the  dead  animal,  it  is  frequently  found  in  a  solid  form, 
constituting  suet,  which,  when  divested  of  the  membrane  in  which  it  is  contained,  is  called 
talloir.     See  Tallow,  Oils,  &c. 

ADIT  or  ADIT  LEVEL.  The  horizontal  entrance  to  a  mine ;  a  passage  or  level 
driven  into  the  hill-side.     The  accompanying  section  gives,  for  the  purpose  of  distinctness, 

an  exaggerated  section  of  a  portion  of 
the  subterranean  workings  of  a  metal- 
liferous mine.  It  should  be  understood 
that  (/  represents  a  mineral  lode,  upon 
which  the  shaft,  a,  has  been  sunk.  At 
a  certain  depth  from  the  surface  of  the 
hill  the  miners  would  be  inconvenienced 
by  water,  consequently  a  level  is  driven 
in  from  the  side  of  the  hill,  b,  through 
which  the  water  flows  off,  and  through 
which  also  the  miner  can  bring  out  the 
broken  rock,  or  any  ores  which  he  may 
obtain.  Proceeding  still  deeper,  sup- 
posing the  workings  to  have  com- 
menced, as  is  commonly  the  case,  at  a 
certain  elevation  above  the  sea-level,  similar  conditions  to  those  described  again  arising, 
another  level  is  driven  so  as  to  intersect  the  shaft  or  shafts,  as  shown  at  c.  In  this  case,  b 
would  be  called  the  shallow,  and  ethe  deep  adit.  The  economy  of  such  works  as  these  is 
great,  saving  the  cost  of  expensive  pumping  machinery,  and,  in  many  cases,  saving  also 
considerable  labor  in  the  removal  of  ores  or  other  matter  from  the  mine. 

ADZE.  A  cutting  instrument ;  differing  from  the  axe  by  the  edge  being  placed  at 
nearly  right  angles  to  the  handle,  and  being  slightly  curved  up  or  inflected  towards  it.  The 
instrument  is  held  in  both  hands,  wliilst  the  operator  stands  upon  his  woik  in  a  stooping 
position  ;  the  handle  being  from  twenty-four  to  thirty  inches  long,  and  the  weight  of  the 
Ijlade  from  two  to  four  pounds.  The  adze  is  swung  in  a  circular  path  almost  of  the  same 
curvature  as  the  blade,  the  shoulder-joint  being  the  centre  of  motion,  and  the  entire  arm 
and  tool  forming,  as  it  were,  one  inflexible  radius ;  the  tool,  therefore,  makes  a  succession 
of  small  arcs,  and  in  each  blow  the  arm  of  the  workman  is  brought  in  contact  with  the 
thigh,  which  serves  as  a  stop  to  prevent  accident.  In  coarse  preparatory  works,  the  work- 
man directs  his  adze  through  the  space  between  his  two  feet ;  he  thus  surprises  us  by  the 
quantity  of  wood  removed  ;  in  fine  works  he  frequently  places  liis  toes  over  the  spot  to  be 
wrought,  and  the  adze  penetrates  two  or  three  inches  beneatli  the  sole  of  the  shoe ;  and  he 
thus  surpi'iscs  us  by  the  apparent  danger,  yet  perfect  working  of  the  instrument,  which,  in 
tlie  hands  of  a  shipwright  in  particular,  almost  rivals  the  joiner's  plane  ;  it  is  with  him  the 
nearly  universal  paring  instrument,  and  is  used  upon  works  in  all  positions. — Holtzapffel. 

AERATED  WATEK.  The  common  commercial  name  of  water  artificially  impregnated 
with  carbonic  acid.  . 

AEROLITES.  Meteoric  stones.  It  cannot  be  denied  that  masses  of  solid  matter  have 
fallen  from  the  atmosphere  upon  the  earth. 

It  is  evident  that  meteoric  stones  are  of  cosmical  origin  ;  and  the  composition,  there- 
fore, of  such  as  have  been  examined,  shows  us  the  composition  of  masses  of  matter  exist- 
ing i)eyond  the  earth.  A  few  analyses  of  meteoric  stones  will  exhibit  the  chemical  charac- 
ter of  these  extraordinary  masses. 

(2)  (3) 

.  .  90-88  .  .  88-98 

.  .  8-45  .  .  10-.S5 

.  .  0-65  .  .  

.  .  0-02  .  .            0-21 

.  . .  .  0-34 

.  .  .  .  0-10 


Iron, 

Nickel, 

Cobalt, 

Copper, 

Tin, 

Phosphorus, 


(1) 

89-78 

8-88 

0-G() 


(4) 
86-64 
13-04 

0-27 


—Brr 


0-05 

'ik  and  Miller. 


AIR.  23 

A  meteorite  fell  at  Dharwar,  in  the  East  Indies,  on  the  15th  of  February,  1848,  which  gave 
58'3  per  cent,  of  silicates  insoluble  in  aqua  regia;  2'5  of  sulphur,  6-76  of  nickel,  and 
22.18  of  iron.  Another  stone  from  Singhur,  near  Ponna,  in  the  Deccan,  gave  earthly  sili- 
cate, 19"5  ;  iron,  69-16 ;  and  nickel,  4-24.  Ehrenberg  examined  a  black  inky  rain-water 
which  fell  in  Ireland  on  the  15th  of  April,  1849,  and  found  the  black  color  to  consist  of 
minute  particles  of  decayed  plants,  which  had  probably  been  brought  by  the  trade  winds, 
and,  floating  in  clouds  of  aqueous  vapor,  had  decayed. 

AEROSTATION;  AERONAUTICS.  The  ascent  into  the  atmosphere  by  means  of 
balloons.     See  Balloons. 

AGARIC  of  the  oak  ;  called  also  surr/eorCs  agaric,  spunk,  touchwood.  A  fungus  found 
growing  on  the  oak,  birch,  willow,  and  other  trees.     See  Amadou. 

AGATE.  An  instrument  used  by  gold-wire  drawers,  so  called  from  the  agate  fixed  in 
the  middle  of  it. 

AGATE.  {Agate,  Fr.  ;  Achat,  Gr.  ;  Achates,  Lat.)  A  sihceous  mineral ;  a  varie- 
gated variety  of  chalcedony. 

This  stone  is  the  'Axottjs  of  the  Greeks,  by  whom  it  was  so  called  after  the  river  in 
Sicily  of  that  name,  whence,  according  to  Theophrastus,  agates  were  first  procured.  Bo- 
chart,  with  much  probability,  deduces  the  name  from  the  Punic  and  Hebrew,  nakad, 
spotted. 

The  colors  of  agate  are  either  arranged  in  parallel  or  concentric  bands,  or  assume  the 
form  of  clouds  or  spots,  or  arborescent  and  moss-like  stains.  These  colors  are  due  to  the 
presence  of  metallic  oxides,  and  when  indistinct,  they  are  frequently  artificially  developed 
or  produced.  By  boiling  the  colorless  stone  in  oil,  and  afterwards  in  sulphuric  acid,  the  oil 
is  absorbed  by  the  more  porous  layers  of  the  stone ;  it  subsequently  becomes  carbonized, 
:iiid  thus  the  contrast  of  the  various  colors  is  heightened.  The  red  varieties,  also,  are  arti- 
ficially produced  by  boiling  them  in  a  solution  of  proto-sulphate  of  iron  ;  after  which,  upon 
exposing  the  stones  to  heat,  peroxide  of  iron  is  formed,  and  thus  red  bands,  or  rings,  of 
varying  intensities,  are  produced.  Cornelians  are  thus  very  commonly  formed  ;  the  color- 
ing matter  of  the  true  stone  being  a  peroxide  of  iron. 

Agates  never  occur  in  a  crystalline  form,  but  in  the  form  of  rounded  pebbles  ;  they  are 
translucent  by  transmitted  light,  but  are  not  transparent,  have  a  wax-like  fracture,  and  they 
are  susceptible  of  a  brilliant  polish.  Agates  are  used  in  the  arts  for  inlaying,  and  for  bur- 
nishing gold  and  silver  :  they  are  also  made  into  mortars  for  chemical  purposes  ;  and  when 
cut  and  polished,  they  are  converted,  in  considerable  quantities,  into  brooches,  bracelets, 
and  other  ornamental  articles.  Agates  are  brought  to  this  country  from  Arabia,  India,  and 
Oberstein,  in  Saxony :  they  are  also  found  in  Perthshire,  and  other  parts  of  Scotland.  The 
Scotch  Pebble  is  a  variety  of  the  agate,  known  by  its  zig-zag  pattern  as  the  Fortification 
Agate.  Agates  are  found  frequently  in  the  amygdaloid  rocks  of  Galgenburg,  near  Ober- 
stein. They  are  usually  ground  into  form,  cut,  and  polished,  at  water-mills  in  the  neigh- 
borhood, where  a  considerable  trade  in  them  is  carried  on.  J/o.ss  .Agate,  or  Mocha  Stone, 
is  a  chalcedony,  containing  within  it  dendritic  or  moss-like  delineations,  of  an  opaque 
brownish-yellow  color,  which  are  due  to  oxide  of  manganese,  or  of  iron. — H.  W.  B. 

Agates  are  found  in  the  Canton  markets,  as  articles  of  commerce,  in  abundance,  and  of 
the  following  varieties  : — The  white-veined  agate,  called  also  Mocha  Stone,  varies  from  1  to 
8  inches  in  diameter.  The  dull,  milky  agate,  not  so  valuable,  occurs  in  sizes  of  1  to  10 
inches.  Lead-colored  agate,  sometimes  uniform,  and  sometimes  spotted,  occurs  of  large 
size,  and  is  used  for  cups  and  boxes.  Flesh-colored.  Blood-colored.  This  is  sometimes 
variegated  with  pale  blue  and  brown ;  the  blue  always  surrounds  the  red  ;  the  brown  has 
the  tint  of  horn.  Clouded  and  spotted  flesh-colored  agate  is  found  subject  to  many  flaws. 
Red  agate,  with  yellow,  is  of  1  to  4  inches  in  diameter.  The  yellow  has  various  tints. 
Sometimes  the  pebbles  are  7  inches  in  length.  The  yellow  agate  is  used  for  knife-handles. 
The  pale  yellow  agate  is  very  scarce  ;  it  is  called  also  Leonina,  being  variegated  with  white, 
black,  and  green,  and  bearing  some  resemblance  to  a  lion's  skin.  Blackish-veined  brown 
agate,  in  pieces  from  2  to  7  inches  in  diameter,  is  very  hard,  and  is  cut  into  seals,  buttons, 
and  heads  of  canes,  &c.,  with  natural  veins,  or  fictitious  colors,  sunk  into  the  stone.  It 
appears  to  be  of  much  value. — Oriental  Covimerce. 

Agate  is  found  sufficiently  large  to  be  formed  into  mortars  for  chemical  purposes. 
"  The  royal  collection  at  Dresden  contains  a  table-service  of  German  agato ;  and  at  Vienna, 
iu  the  Imperial  cabinet,  there  is  an  oval  dish,  twenty-two  inches  in  length,  formed  of  a 
.  single  stone." — Dana. 

Agates  may  be  stained  artificially  by  soaking  in  a  solution  of  nitrate  of  silver,  and  after- 
wards exposing  them  to  the  sun.  These  artificial  colors  disapi)ear  on  laying  the  stone  for  a 
night  in  aquafortis.  A  knowledge  of  the  practicability  of  thus  staining  agates  naturally  leads 
to  the  susjiieion  of  many  of  the  colors  being-  the  work,  not  of  nature,  but  of  art. 

AIR.  The  gaseous  cnveloi)e  which  surrounds  this  Earth  is  emphatically  so  called  ;  it 
consists  of  the  gases  nitrogen  and  oxygen. 

About  79  measures  of  nitrogen,  or  azote,  and  21  of  oxygen,  with  Yjgth  of  carbonic  acid, 


24  AIR-ENGINE. . 

constitute  the  air  we  breathe.     The  term  air  is  applied  to  any  permanently  gaseous  body. 
And  we  express  ditlerent  conditions  of  the  air,  as  good  air,  bad  air,  foul  air,  kc. 

AIR-ENGINE.  The  considerable  expansibility  of  air  by  heat  naturally  suggested  its  use 
as  a  motive  power  long  bel'ore  theoretical  investigation  demonstrated  its  actual  value.  The 
great  advance  made  during  the  few  last  years  in  our  knowledge  of  the  mechanical  action  of 
heat,  has  enabled  us  to  determine. with  certainty  the  practical  result  which  may  be  obtained 
bv  the  use  of  any  contrivance  for  employing  heat  as  a  jirime  mover  of  machinery.  \Vc  are 
indebted  to  Professor  Wm.  Thomson  for  the  fundamental  theorem  which  decides  the 
economy  of  any  thermo-dynamic  engine.  It  is — that  in  any  perfectly  constructed  engine 
the  fraction  of  heat  converted  into  work  is  equal  to  the  range  of  temperature  from  the 
highest  to  the  lowest  point,  divided  by  the  highest  temijcrature  reckoned  from  the  zero  of 
absolute  temperature.     Thus,  if  we  have  a  perfect  engine  in  which  the  highest  temperature 

is  ''SO"  and  the  lowest  80'  F.,  the  fraction  of  heat   converted  into  force  will  be  — . — L 

260-]- 4G0, 

or  rather  more  than  one  quarter.  So  that,  if  we  use  a  coal  of  which  one  pound  in  combus- 
tion gives  out  heat  equivalent  to  10,380,000  foot  pounds,  such  an  engine  as  we  have  just 
described  would  produce  work  equal  to  2,805,405  foot  pounds  for  each  pound  of  coal 
consumed  in  the  furnace.  From  the  above  formula  of  Professor  Thomson,  it  will  appear 
that  the  economy  of  any  perfect  thermo-dynamic  engine  depends  upon  the  range  of  tem- 
perature we  can  obtain  in  it.  And  as  the  lowest  ten;perature  is  generally  nearly  constant, 
being  ruled  by  the  temperature  of  the  surface  of  the  earth,  it  follows  that  the  higher  we  can 
raise''  the  highest  temperature,  the  more  economical  will  be  the  engine.  The  question  is 
thus  reduced  to  this: — In  what  class  of  engine  can  we  practically  use  the  highest  tempera- 
ture? In  the  steam-engine  worked  with  saturated  viijior,  the  limit  is  obviously  deter- 
mined by  the  amount  of  pressure  which  can  be  safely  employed.  In  the  steam-engine 
worked  with  super-heated  vapor — i.  e.  in  which  the  vapor,  after  passing  from  the  boiler, 
receives  an  additional  charge  of  heat  without  being  allowed  to  take  up  more  water — and 
also  in  the  air-engine,  the  limit  will  depend  upon  the  temperature  at  which  steam  or  air  acts 
chemically  upon  the  metals  employed,  as  well  as  upon  tl  e  power  of  the  metals  themselves 
to  resist  the  destructive  action  of  lieat.  It  thus  appears  that  the  steam-engine  worked  with 
superheated  steam  possesses  most  of  the  economical  advantages  of  the  air-engine.  But 
when  we  consider  that  an  air-engine  may  be  made  available  where  a  plentiful  supply  of 
water  cannot  be  readily  obtained,  the  importance  of  this  kind  of  thermo-dynamic  engine  is 
incontestable.  The  merit  of  first  constructing  a  practical  air-engine  belongs  to  Mr.  Stirling. 
Mr.  Ericsson  has  subsequently  introduced  various  refinements,  such  as  the  respirator — a 
reticulated  mass  of  metal,  which,  by  its  extensive  conducting  surface,  is  able,  almost  instan- 
taneously, to  give  its  own  temperature  to  the  air  which  passes  through  it.  But  various 
practical"  difficulties  attend  these  refinements,  which,  at  best,  only  applyto  engines  Morkcd 
between  particular  temperatures.  The  least  complex  engine,  and  that  which  would  probably 
prove  most  effectual  in  practice,  is  that  described  in  the  "  Philosophical  Transactions," 
1852,  Part  I.  It  consists  of  a  pump,  which  compresses  air  into  a  receiver,  in  which  it 
receives  an  additional  charge  of  heat ;  and  a  cylinder,  the  piston  of  which  is  worked  Vjy  the 
heated  air  as  it  escapes.  The  difference  between  the  work  produced  by  the  cylinder  and 
that  absorbed  by  the  pump  constitutes  the  force  of  the  engine  ;  which,  being  compared  with 
the  heat  communicated  to  the  receiver,  gives  results  exactly  conformable  with  the  law  of 
Professor  Thomson  above  described. — J.  P.  J. 

Dr.  Joule  has  proposed  various  engines  to  lie  worked  at  temperatures  below  redness, 
which,  if  no  loss  occurred  by  friction  or  radiation,  would  realize  about  one-half  the  work  due 
to  the  heat  of  combustion  ;  "or  about  four  times  the  economical  duty  which  has,  as  yet,  been 
attained  by  the  most  perfect  steam-engine. 

A  detailed  account  of  Ericssons  Calorific  Engine  may  be  useful,  especially  as  a  certain 
amount  of  success  has  attended  his  efforts  in  applying  the  expansive  power  of  heat  to  move 
machinery.  It  is  stated  in  Hunt's  "  Merchant's  Magazine"  that  Ericsson's  engines  are  at 
work  in  the  foundry  of  Messrs.  Hogg  and  Delamater,  in  New  York  ;  one  engine  being  of 
five  and  another  of  sixty-hor.se  power.  The  latter  has  four  cylinders.  Two,  of  seventy-two 
inches  in  diameter,  stand  side  by  side.  Over  each  of  these  is  placed  one  much  smaller. 
Within  these  are  pistons  exactly  fitting  their  respective  cylinders,  and  so  connected,  that 
those  within  the  lower  and  upper  cylinders  move  together.  Under  the  bottom  of  each  of 
the  lower  cylinders  a  fire  is  applied,  no  other  furnaces  being  employed.  Neither  boilers  nor 
water  are  used.  The  lower  is  called  the  working  cylinder  ;  the  upper,  the  supply  cylinder. 
As  the  piston  in  the  .supply  cylinder  moves  down,  valves  placed  in  its  top,  open,  and  it 
))ecomcs  filled  with  cold  air.'  As  the  piston  rises  within  it,  these  valves  close,  and  the  air 
within,  unable  to  escape  as  it  came,  passes  through  another  set  of  valves  into  a  receiver, 
from  whence  it  has  to  pass  into  the  working  cylinder  to  force  up  the  working  piston  within 
it.  As  it  leaves  the  receiver  to  perform  this  duty,  it  passes  through  what  is  called  the 
rer/enernfor,  where  it  Ijeeomes  heated  to  about  450"  ;  and  upon  entering  the  working  cylin- 
der, it  is  further  lieatod  bv  the  supply  underneath.     For  the  sake  of  illustration,  merely,  let 


ALABASTER.  25 

us  suppose  that  the  working  cyhnder  contains  double  the  area  of  the  supply  cylinder  :  the 
cold  air  which  entered  the  upper  cylinder  will,  therefore,  but  only  half  fill  the  lower  one. 
In  the  course  of  its  passage  to  the  latter,  however,  it  passes  tin-ough  the  ref/c iterator  ;  and 
as  it  enters  tlie  working  cylinder,  we  will  suppose  that  it  has  become  heated  to  about  480\ 
l)y  wliieh  it  is  expanded  to  double  its  volume,  and  with  tliis  increased  capacity  it  enters  the 
working  cylinder.  We  will  further  suppose  the  area  of  the  piston  within  this  cylinder  to 
contain  1,000  square  inches,  and  the  area  of  the  piston  in  the  supply  cylinder  above  to 
contain  but  5U0.  The  air  presses  upon  this  with  a  mean  force,  we  will  suppose,  of  about 
eleven  pounds  to  each  square  inch ;  or,  in  other  words,  with  a  weight  of  5,500  pounds. 
Upon  tJie  surface  of  the  lower  piston  tlie  heated  air  is,  however,  pressing  upwards  with  a 
like  force  upon  e.ach  of  its  1,000  square  inches ;  or,  in  other  words,  with  a  force  which, 
after  overcoming  the  weight  above,  leaves  a  surplus  of  5,500  pounds,  if  we  make  no  allow- 
ance for  friction.  This  surplus  furnishes  the  working  power  of  the  engine.  It  will  be  seen 
that  after  one  stroke  of  its  piston  is  made,  it  will  continue  to  work  with  this  force  so  long 
as  sufficient  heat  is  supplied  to  expand  the  air  in  the  working  cylinder  to  the  extent  stated  ; 
for,  so  long  as  the  area  of  the  lower  piston  is  greater  than  that  of  the  upper  and  a  like 
pressure  is  upon  every  square  inch  of  each,  so  long  will  the  greater  piston  push  forward  the 
smaller,  as  a  two-pound  weight  upon  one  end  of  a  balance  will  be  sure  to  bear  down  a  one- 
pound  weight  placed  on  the  other.  We  need  hardly  say,  that  after  the  air  in  the  working 
cylinder  has  forced  up  the  piston  within  it,  a  valve  opens ;  and  as  it  passes  out,  the  pistons, 
by  the  force  of  gravity,  descend,  and  cold  air  again  rushes  into  and  fills  the  supply  cylinder. 
In  this  manner  the  two  cylinders  are  alternately  supplied  and  discharged,  causing  the 
pistons  in  each  to  play  up  and  down  substantially  as  they  do  in  the  steam-engine. 

The  regenerator  must  now  be  described.  It  has  been  stated  that  atmospheric  air  is  first 
drawn  into  the  supply  cylinder,  and  that  it  passes  through  the  regenerator  into  the  working 
cylinder.  The  regenerator  is  composed  of  wire  net,  like  that  used  in  the  manufacture  of 
sieves,  placed  side  by  side,  until  the  series  attains  a  thickness  of  about  12  inches.  Through 
the  almost  innumerable  cells  formed  by  the  intersections  of  the  wire,  the  air  must  pass  on  its 
way  to  the  working  cylinder.  In  passing  through  these  it  is  so  minutely  divided  that  all 
parts  are  brought  into  contact  with  the  wires.  Supposing  the  side  of  the  regenerator  nearest 
the  working  cylinder  is  heated  to  a  high  temperature,  the  air,  in  passing  through  it,  takes 
up,  as  we  have  said,  about  450'  of  the  480°  of  heat  required  to  double  the  volume  of  the 
air ;  the  additional  30'  are  communicated  by  the  fire  beneath  the  cylinder. 

The  air  has  thus  become  expanded,  it  forces  the  piston  upwards ;  it  has  done  its  work 
— valves  open,  and  the  imprisoned  air,  heated  to  480",  passes  from  the  cylinder  and  a"-ain 
enters  the  regenerator,  through  which  it  must  pass  before  leaving  the  machine.  It  has  been 
said  that  the  side  of  this  instrument  nearest  the  cylinder  is  kept  hot ;  the  other  side  is  kept 
cool  by  the  action  upon  it  of  the  air  entering  in  the  opposite  direction  at  each  up-stroke  of 
the  pistons ;  consequently,  as  the  air  from  the  working  cylinder  passes  out,  the  wires  al)sorb 
the  heat  so  effectually,  that  when  it  leaves  the  regenerator  it  has  been  robbed  of  it  all, 
except  about  30°. 

The  regenerator  in  the  60-horse  engine  measures  20  inches  in  height  and  width,  inter- 
nally. Each  disk  of  wire  composing  it  contains  07G  superficial  inches,  and  the  net  has  10 
meshes  to  the  inch.  Each  superficial  inch,  therefore,  contains  100  meshes,  which,  multiplied 
by  076,  gives  67,600  meshes  in  each  disk  ;  and,  as  200  disks  are  employed,  it  follows  that 
the  regenerator  contains  13,520,000  meshes;  and  consequently,  as  there  are  as  many 
spaces  between  the  disks  as  there  are  meshes,  we  find  that  the  air  within  it  is  distriljuted  in 
about  27,000,000  minute  ceHs.  Thence  every  particle  of  air,  in  passing  through  the  regen- 
erator, is  brought  into  very  close  contact  with  a  surface  of  metal  which  heats  and  cools  it 
alternately.  Upon  this  action  of  the  regenerator,  Ericsson's  Calorific  Engine  depends.  In 
its  application  on  the  large  scale,  contemplated  in  the  great  Atlantic  steamer  called  the 
"  Ericsson,"  the  result  was  not  satisfactory.  We  may,  however,  notwithstanding  this  result 
safely  predicate,  from  the  investigation  of  Messrs.  Thomson  and  Joule,  that  the  expansion 
of  air  by  heat  will  eventually,  in  some  conditions,  take  the  place  of  steam  as  a  motive 
power. 

AIR-GUN.  This  is  a  weapon  in  which  the  clastic  force  of  air  is  made  use  of  to  project 
the  ball.  It  is_  so  arranged,  that  in  a  cavity  in  the  stock  of  the  gun,  air  can  be,  bv  means  of  a 
piston,  powerfully  condensed.  Here  is  a  reserved  force,  which,  upon  its  being  relieved 
from  pressure,  is  at  once  exerted.  When  air  has  been  condensed  to  about  ^\  of  its  bulk, 
it  exerts  a  force  which  is  still  very  inferior  to  that  of  gunpowder.  In  many  other  respects 
the  air-gun  is  l)ut  an  imperfect  weapon,  consecpiently  it  is  rarely  employed. 

AIIIO-IIYDROGEN  BLOWPII'E.  A  blowpipe  in  which 'air  is  used  in  the  place  of 
oxygen,  to  comljine  with  and  give  intensity  of  heat  to  a  hydrogen  flame  for  the  purposes  (jf 
soldering.     Sec  AuTonENoi:s  Soi.nKiuNG. 

AL.A.B.\STER,  Gi/psum,  Plaster  of  Parh  (Alhdf.rr,  Fr.  ;  Jla'i(f<ter,  Germ.),  a  sulphate 
of  lime.  (See  Alabastku,  Oiukntal.)  When  massive,  it  is  calknl  indifferently  alabaster  or 
gypsum  ;  and  when  in  distinct  and  separate  crystals,  it  is  termed  selcnite.     Massive  alabas- 


26  ALABASTER,  OPJENTAL. 

ter  occurs  in  Britain  m  the  new  red  or  keuper  marl :  in  Glamorganshire,  on  the  Bristol 
Chaimel ;  in  Leicestershire,  at  Syston ;  at  Tutbury  and  near  Burton-on-Trent,  in  Stafford- 
shire ;  at  Chellaston,  in  Derbyshire  ;  near  Droitwich  it  is  associated  in  the  marl  with  rock 
salt,  in  strata  respectively  40  and  75  feet  in  thickness  ;  and  at  Xoithwich  and  elsewhere  the 
red  marl  is  intersected  with  frequent  veins  of  gypsum.  At  Tutbury  it  is  quarried  in  the 
open  air,  and  at  Chellaston  in  caverns,  whore  it  is  blasted  by  gunpowder ;  at  both  places  it 
is  burned  in  kilns,  and  otherwise  prepared  for  the  market.  It  lies  in  irregular  beds  in  the 
marl,  that  at  Chellaston  being  about  30  feet  thick.  There  is,  however,  reason  to  suppose 
that  it  v/as  not  originally  deposited  along  with  the  marl  as  sulphate  of  lime,  but  rather  that 
calcareous  strata,  by  the  access  of  sulphuric  acid  and  water,  liave  been  converted  into  sul- 
phate of  lime, — a  circumstance  quite  consistent  with  the  bulging  of  the  beds  of  marl  with 
which  the  gypsum  is  associated,  the  lime,  as  a  sulphate,  occujjying  more  space  than  it  did  in 
its  original  state  as  a  carbonate.  At  Tutbury  and  elsewhere,  though  it  lies  on  a  given 
general  horizon,  yet  it  can  scarcely  be  said  to  be  truly  bedded,  but  ramifies  among  the  beds 
and  joints  of  the  marl  in  numerous  films,  veins,  and  layers  of  fibrous  gypsum. 

A  snow-white  alabaster  occurs  at  Tolterra,  in  Tuscany,  much  used  in  works  of  art  in 
Florence  and  Leghorn.  In  the  Paris  basin  it  occurs  as  a  granular  crystalline  rock,  in  the 
Lower  Tertiary  rocks,  known  to  geologists  as  the  upper  part  of  the  Middle  Eocene  fresh- 
water strata.  It  is  associated  with  beds  of  white  and  green  marls  ;  but  in  the  Thuringewald 
there  is  a  great  mass  of  sulphate  of  lime  in  the  Permian  strata.  It  has  been  sunk  through 
to  a  depth  of  70  feet,  and  is  believed  to  be  metamorphosed  magnesian  limestone  or  Zech- 
stein.  In  the  United  States  this  calcareous  salt  occurs  in  numerous  lenticular  masses  in 
marly  and  sand  strata,  of  that  pa-  jf  the  Upper  Silurian  strata  known  as  the  Onondaga  salt 
group.  It  is  excavated  for  agricultural  purposes.  For  mineralogical  character,  &c.,  see 
Gypsum.— A.  C.  R. 

The  gypsum  of  our  own  coimtry  is  found,  in  apparently  inexhaustible  quantities,  in  the 
red  marl  formation  in  the  neighborhood  of  Derby,  and  has  been  worked  for  many  centuries. 
The  great  bulk  of  it  is  used  for  making  plaster  of  Paris,  and  as  a  manure ;  and  it  is  the 
basis  of  many  kinds  of  cements,  patented — as  Keene's,  Martin's,  and  others. 

To  get  it  for  these  purposes,  it  is  worked  by  mining  underground,  and  the  Etone  is 
blasted  by  gunpowder ;  but  this  shakes  it  so  much  as  to  be  unfit  for  working  into  orna- 
ments, &c. ;  to  procure  blocks  for  which  it  is  necessary  to  have  an  open  quarry.  By 
removing  the  superincumbent  marl,  and  laying  bare  a  large  surface  of  the  rock,  the  alabaster 
being  very  irregular  in  form,  and  jutting  out  in  several  parts,  allows  of  its  being  sami  out 
in  blocks  of  considerable  size,  and  comparatively  sound,  (as  is  illustrated  by  the  large  tazza 
in  the  Museum  of  Practical  Geology.)  This  stone,  when  protected  from  the  action  of  water, 
is  extremely  durable,  as  may  be  seen  in  churches  all  over  the  country,  where  monumental 
effigies,  many  centuries  old,  are  now  as  perfect  as  the  day  they  were  made,  excepting,  of 
course,  wilful  injuries ;  but  exposure  to  rain  soon  decomposes  the  stone,  and  it  must  be 
borne  in  mind  that  it  is  perfectly  unsuited  for  garden  vases  or  other  out-door  work  in  this 
country. 

In  working,  it  can  be  sawn  up  into  slabs  with  toothed  saws,  and  for  working  mouldings 
and  sculptures,  fine  chisels,  rasps,  and  files  are  the  implements  used  ;  the  polishing  is  per- 
formed by  rubbing  it  with  pieces  of  sandstone,  of  various  degrees  of  fineness,_and  water, 
until  it  is  "quite  free  from  scratches,  and  then  giving  a  gloss  by  means  of  polishing  powder 
(oxide  of  tin)  applied  on  a  piece  of  cloth,  and  rubbed  with  a  considerable  degree  of  friction 
on  the  stone.  This  material  gives  employment  in  Derby  to  a  good  many  hands  in  forming 
it  into  useful  and  ornamental  articles,  and  is  commonly  called  Derbyshire  Spar ;  most  of 
the  articles  arc  turned  in  the  lathe,  and  it  works  something  like  very  hard  wood. 

Another  kind  of  gypsum  also  found  in  Derbyshire  is  the  fibrous  or  silky  kind ;  it  occurs 
in  thin  beds,  from  one  to  six  inches  in  depth,  and  is  crystallized  in  long  needle-like  fibres ; 
being  easily  worked,  susceptible  of  a  high  polish,  and  quite  lustrous,  it  is  used  for  making 
necklaces,  bracelets,  brooches,  and  such  like  small  articles. — S.  II. 

ALABASTER,  ORIENTAL.  Oriental  alabaster  is  a  form  of  stalagmitic  or  stalactitic 
cariionate  of  lime,  an  Egvptian  variety  of  which  is  highly  esteemed.  It  is  also  procured 
from  the  Pyrenees,  from^Chili,  and  from  parts  of  the  United  States  of  America.  Ancient 
quarries  are  still  in  existence  in  the  province  of  Oran,  in  Algeria. 

ALBATA  PLATE,  a  name  given  to  one  of  the  varieties  of  white  metal  now  so  com- 
monly emplovcd.     See  Copper,  and  Alloys. 

ALBUM  GRyECUM.  The  white  freces  of  dogs.  After  the  hair  has  been  removed 
from  skins,  this  is  u?:ed  to  preserve  the  softness  of  them,  and  prepare  them  for  the  tan-pit. 
Fowls'  dun?  is  considered  by  practical  tanners  as  superior  to  the  dung  of  dogs,  and  this  is 
oljtained  as  largely  as  possililc.  These  excreta  may  be  said  to  be  essentially  phosphate  of 
lime  and  mucus.  "We  are  informed  that  various  artificial  compounds  which  represent, 
chemically,  the  conditions  of  those  natural  ones,  have  been  tried  without  producing  the 
same  good  results.     It  is  a  reflection  on  our  science,  if  this  is  really  the  case. 

ALBUMEN.     {Album  Ovi.)    Albumen  is  a  substance  which  forms  a  constituent  part 


ALCOHOL.  27 

of  the  animal  fluids  and  solids,  and  which  is  also  found  in  the  vegetable  kingdom.  It 
exists  nearly  pure  in  the  white  of  egg.     Albumen  consists  of— 

Carbon, 53-32 

Hydrogen,        ......  ^"i^ 

Nitrogen,  .......  lo"? 

Sulphur,  .  .  .  .  .  .  1'3 

Oxygen, 22-39 

Its  Formula  being  S'*  N"'  C"'^  H'^'  0"^  Albumen  coagulates  by  heat,  as  is  illustrated  in 
the  boilin"-  of  an  egg.  The  salts  of  tin,  bismuth,  lead,  silver,  and  mercury  form  with 
albumen  white  insoluble  precipitates ;  therefore,  in  cases  of  poisoning  by  corrosive  sub- 
limate, nitrate  of  silver,  or  sugar  of  lead,  the  white  of  egg  is  the  best  antidote  which  can 
be  administered. 

Albumen  is  employed  in  Photography,  wliich  see. 

We  imported  the  following  quantities  of  albumen: — in  1855,  2T5  cwts.  ;  in  1S56, 
382  cwts. 

ALCOHOL.  (Alcool,  Fr.  ;  Alkohol,  or  Weingeist,  Germ.)  The  word  alcohol  is  de- 
rived from  the  Hebrew  word  '^  kohol,'^  >nD  to  paint.  The  oriental  females  were  and  are 
still  in  the  habit  of  painting  the  eyebrows  with  various  pigments ;  the  one  generally  em- 
ployed was  a  preparation  of  antimony,  and  to  this  the  term  was  generally  applied.  It 
became,  however,  gradually  extended  to  all  substances  used  for  the  purpose,  and  ultimately 
to  strong  spirits,  wliich  were  employed,  probably,  as  solvents  for  certain  coloring  principles. 
The  term  was  subsequently  exclusively  used  to  designate  ardent  spirits,  and  ultimately  the 
radica'  or  principle  upon  which  their  strength  depends. 

As  chemistry  advanced,  alcohol  was  found  to  be  a  member  only  of  a  class  of  bodies 
agreeing  with  it  iii  general  characters ;  and  hence  the  term  is  now  generic,  and  we  speak 
of  the  various  alcohols.  Of  these,  common  or  vinous  alcohol  is  the  best  known  ;  and,  in 
common  life,  by  "  alcoholic  liquors,"  we  invariably  mean  those  containing  the  original  or 
vinous  alcohol. 

When  the  characters  of  ordinary  alcohol  have  been  stated,  allusion  will  be  made  to  lie 
class  of  bodies  of  which  this  is  the  type. 

Fermented  liquors  were  known  in  the  most  remote  ages  of  antiquity.  We  read  (Gene- 
sis ix.)  that  after  the  flood  "  Noah  planted  a  vineyard,  and  he  drank  of  the  wine  and  was 
drunken."  Homer,  who  certainly  lived  900  years  before  the  Christian  era,  also  frequently 
mentions  wine,  and  notices  its  efftxits  on  the  body  and  mind  (Odyssey  IX.  and  XXI.) ;  and 
Herodotus  tells  us  that  the  Egyptians  drank  a  liquor  fermented  from  barley.  The  period 
when  fermented  liquors  were  submitted  to  distillation,  so  as  to  obtain  "  ardent  spirits,'^  is 
shrouded  in  much  obscurity.  Raymond  Lully*  was  acquainted  with  "  spirits  of  wine,"  which 
he  called  aqua  ardens.  The  separation  of  absolute  alcohol  would  appear  to  have  been 
first  efFected  about  this  period  (1300),  by  Arnauld  de  Yillencuve,  a  celebrated  physician 
residing  in  Montpellier  {Gerhardt),  and  its  analysis  was  first  performed  by  Th.  de 
Saussure.f 

The  preparation  of  alcohol  may  be  divided  into  three  stages : — 

1.  Tlie  production  of  a  fermented  vinous  liquor — the  Fermentation. 

2.  The  preparation  from  this  of  an  ardent  spirit — the  Distillation. 

3.  The  separation  from  this  ardent  spirit  of  the  last  traces  of  water — the  Rectification. 
1.  Fermentation.      The  term    "fermentation"   is   now  applied   to   those   mysterious 

changes  which  vegetable  (and  animal)  substances  undei-go  when  exposed,  at  a  certain  tem- 
perature, to  contact  with  organic  or  eve*  organized  bodies  in  a  state  of  change. 

There  are  several  bodies  which  suffer  these  metamorphoses,  and  under  the  influence  of 
a  great  number  of  different  exciting  substances,  which  are  termed  the  "ferments;"  more- 
over, the  resulting  products  depend  greatly  upon  the  temperature  at  which  the  change  takes 
place. 

The  earliest  known  and  best  studied  of  these  processes  is  the  one  commonly  i-ecognized 
as  the  vinous  or  alcoholic  fermentation. 

In  this  process  solutions  containing  sufiar — either  the  juice  of  the  grape  (see  Wink)  or 
•an  infusion  of  germinated  barley,  malt,  (see  Bkkii) — arc  mixed  with  a  suitable  quantity  of 
a  ferment ;  beer  or  wine  yeast  is  usually  employed  (see  Yicast),  and  the  whole  maintained 
at  a  temperature  of  between  TO"  and  80"  F.  ('21°  to  2G"  C.) 

Other  bodies  in  a  state  of  putrefactive  decomposition  will  effect  the  same  result  as  the 
yca-t,  swell  as  putrid  )>lood,  white  of  egg,  &c. 

The  licjuid  swells  up,  a  considerable  quantity  of  froth  collects  on  the  surface,  and  an 
abundance  of  gas  is  disengaged,  wliich  is  ordinary  carbonic  acid  (CO").  The  composition 
of  (pure)  alcohol  is  expressed  Ijy  t!ie  formula  C*  H"  0^  and  it  is  jiroduced  in  this  process 

•  'riioiiison'.'*  History  of  Chemistry,  1.  41.     (1S30.)  t  .Vuuuk-s  do  Chimio,  xlit.  225. 


28 


ALCOHOL. 


by  the  breaking  up  of  an  equivalent  of  (/rape  sugar,  G^*  W^  0^',  into  4  equivalents  of  alco- 
hol, 8  of  carbonic  acid,  and  4  of  water — 

Qli   2-.«  028 

C"  H-^  0°    =  4  (C*  H«  0') 

H<  0*    =4  HO 
8  CO' 


C 


0' 


It  is  invariably  the  grape  sugar  which  undergoes  this  change  ;  if  the  solution  contains 
cane  sugar,  the  cane  sugar  is  iirst  converted  into  grape  sugar  under  the  influence  of  the 
ferment.     See  Sugar. 

Much  diversity  of  opinion  exists  with  respect  to  the  office  which  the  ferment  performs 
in  this  process,  since  it  does  not  itself  yield  any  of  the  products.     See  Fermentation. 

Tlie  liquid  obtained  by  the  vinous  fermentation  has  received  different  names,  according 
to  the  source  whence  the  saccharine  solution  was  derived.  When  procured  from  the  ex- 
pressed juice  of  fruits — such  as  grapes,  currants,  gooseberries,  kc. — the  product  is  denomi- 
nated u'ine ;  from  a  decoction  of  malt,  ale  or  bier ;  from  a  mixture  of  honey  and  water, 
mead;  from  apples,  cider ;  from  the  leaves  and  small  branches  of  the  spruce-fir  (abies 
excclxa,  &c. ),  together  with  sugar  or  treacle,  spruce ;  from  rice,  vice  beer  (which  yields  the 
spirit  arrack) ;  from  coc-oa-nut  juice,  pcdm  wine. 

It  is  an  interesting  fact  that  alcohol  is  produced  in  very  considerable  quantities  (in  the 
aggregate)  during  the  raising  of  bread.  The  carbonic  acid  which  is  generated  in  the  dough, 
and  which  during  its  expulsion  raises  the  bread,  is  one  of  the  products  of  the  fermentation 
of  the  sugar  in  the  flour,  under  the  influence  of  the  yeast  added ;  and  of  course  at  the 
same  time  the  complementary  product,  alcohol,  is  generated.  As  Messrs.  Ronalds  and 
Richardson  remark  :*  "  The  enormous  amount  of  bread  that  is  baked  in  large  towns — in 
London,  for  instance,  8.8  millions  of  cwts.  yearly — would  render  the  small  amount  of 
alcohol  contained  in  it  of  sufficient  importance  to  be  worth  collecting,  provided  this  could 
be  done  sufficiently  cheaply."  In  London  it  has  been  estimated  that  in  this  way  about 
300,000  gallons  of  spirits  are  annually  lost ;  but  the  cost  of  collecring  it  would  far  exceed 
its  value. 

2.  Distillation.  By  the  process  of  distillaiion,  ardent  spirits  are  obtained,  which  have 
likewise  received  diff"erent  names  according  to  the  sources  whence  the  fermented  liquor  has 
been  derived :  viz.  that  produced  by  the  distillation  of  wine  being  called  brandi/,  and  in 
France  cognac,  or  eau  de  vie  ;  that  produced  by  the  distillation  of  the  fermented  liquor 
from  sugar  and  molasses,  rum.  There  are  several  varieties  of  spirits  made  from  the  fer- 
mented liquor  procured  from  the  cereals  (and  especially  barley),  known  according  to  their 
peculiar  methods  of  manufacture,  flavor,  <S:c. — as  vhiskci/,  gin,  Hollands — the  various 
compounds  and  liqueurs.  In  India,  the  spirit  obtained  from  a  fermented  infusion  of  rice 
is  called  arrack. 

3.  Rectification  ;  preparation  of  absolute  alcohol.  It  is  impossible  by  distillation  alone 
to  deprive  spirit  of  the  whole  of  the  water  and  other  impurities — to  obtain,  in  fact,  pure  or 
absolute  alcohol. 

This  is  effected  by  mixing  with  the  liquid  obtained  after  one  or  two  distillations,  certain 
bodies  which  have  a  powerful  attraction  for  water.  The  agents  commonly  employed  for 
this  purpose  are  quicklime,  carbonate  of  potash,  anhydrous  sulphate  of  copper,  or  chloride 
of  calcium.  Perhaps  the  best  adapted  for  the  purpose,  especially  where  large  quantities 
are  required,  is  quicklime  ;  it  is  powdered,  mixed  in  the  retort  with  the  spirit  (previously 
tmce  distilled),  and  the  neck  of  the  retort  being*  securely  closed,  the  whole  left  for  24 
hours,  occasionally  shaking  ;  during  this  period  the  lime  combines  with  the  water,  and  then 
on  carefully  distilling,  avoiding  to  continue  the  process  until  tlie  last  portions  come  over,  an 
alcohol  is  obtained  which  is  free  from  water.  If  not  quite  free,  the  same  process  may  be 
again  repeated. 

In  experiments  on  a  small  scale,  an  ordinary  glass  retort  may  be  employed,  heated  by  a 
water-bath,  and  fitted  to  a  Liebig's  condenser  cooled  by  ice-water,  which  passes  lastly  into  a 
glass  receiver,  similarly  cooled. 

Although  alcohol  of  sufficient  purity  for  most  practical  purposes  can  bo  readily  ob* 
tained,  yet  the  task  of  procuring  absolute  alcohol  entirely  free  from  a  trace  of  water,  is  by 
no  means  an  easy  one. 

Mr.  Drinkwatcr  •}•  effected  this  by  digesting  ordinary  alcohol  of  specific  gravity  .850  at 
CO"  F.  for  24  hours  with  carbonate  of  potash  previously  exposed  to  a  red  heat ;  the  alcohol 
was  then  carefully  poured  off"  and  mixed  in  a  retort  with  as  much  fresh-burnt  quicklime  as 
was  sufficient  to  absorb  the  whole  of  the  alcohol ;  after  digesting  for  48  hours,  it  was  slowly 

*  Chemical  Technoloj.n,-,  by  Dr.  F.  Knapp:  edited  by  Messrs.  Konalds  and  Richardson.     Vol.  iii.  19S. 
t  On  the  Preparation  of  Ab.solute  Alcohol,  and  the  Composition  of  Proof  Spirit.     See  Memoirs  of  the 
Clieniical  Society,  vol.  iii.  p.  447. 


ALCOHOL. 


29 


distilled  in  a  water-bath  at  a  temperature  of  about  180°  F.  This  alcohol  was  carefully  re- 
distilled, and  its  specific  gravity  at  00="  F.  found  to  be  -7947,  which  closely  agrees  with  that 
given  by  Guy-Lussac  as  the  specific  gravity  of  absolute  alcohol.  lie  found,  moreover,  that 
recently  i'niited  anliydrous  sulphate  of  copper  was  a  less  efficient  dehydrating  agent  than 
quicklime. 

Graham  recommends  that  the  quantity  of  lime  employed  should  never  exceed  three 
times  the  weight  of  the  alcohol. 

Chloride  of  calcium  is  not  so  well  adapted  for  the  purification  of  alcohol,  since  the 
alcohol  forms  a  compound  with  this  salt. 

Many  other  processes  have  been  suggested  for  depriving  alcohol  of  its  water. 

A  curious  process  was  proposed  many  years  ago  by  Soemmering,*  which  is  dependent 
upon  the  peculiar  fact,  that  whilst  water  moistens  animal  tissues,  alcohol  does  not,  but  tends 
rather  to  abstract  water  from  them.  If  a  mixture  of  alcohol  and  water  be  enclosed  in  an 
ox  bladder,  the  water  gradually  traverses  the  membrane  and  evaporates,  whilst  the  alcohol 
does  not,  and  consequently  by  the  loss  of  water  the  spirituous  solution  becomes  con- 
centrated. 

This  process,  though  an  interesting  illustration  of  exosmose,  is  not  practically  applicable 
to  the  production  of  anhydrous  alcohol ;  it  is,  however,  an  economical  method,  and  well 
suited  for  obtaining  alcohol  for  the  preparation  of  varnishes.  Smugglers,  who  bring  spirits 
into  France  in  bladders  hid  about  their  persons,  have  long  known,  that  although  the  liquor 
decreased  in  bulk,  yet  it  increased  in  strength  ;  hence  the  people  preferred  the  article  con- 
vej'e4clandestinely!  Prof.  Graham  has  ingeniously  proposed  to  concentrate  alcohol  as  follows : 

"A  large  shallow  basin  is  covered,  to  a  small  depth,  with  recently  burnt  quicklime,  in 
coarse  powder,  and  a  smaller  basin,  containing  three  or  four  ounces  of  commercial  alcohol, 
is  made  to  rest  upon  the  lime  ;  the  whole  is  placed  under  the  low  receiver  of  an  air-pump, 
and  the  exhaustion  continued  till  the  alcohol  evinces  signs  of  ebullition.  Of  the  mingled 
vapors  of  alcohol  and  water  which  now  fill  the  receiver,  the  quicklime  is  capable  of  uniting 
with  the  aqueous  only,  which  is  therefore  rapidly  withdrawn,  while  the  alcohol  vapor  is  un- 
affected ;  and  as  water  cannot  remain  in  the  alcohol  as  long  as  the  superincumbent  atmos- 
plicre  is  devoid  of  moisture,  more  aciueous  vapor  rises,  which  is  likewise  abstracted  by  the 
lime,  and  thus  the  process  goes  on  till  the  whole  of  the  water  in  the  alcohol  is  removed. 
Several  days  are  always  required  for  this  purpose. 

Properties  of  Alcohol. — Ahxolute. 

In  the  state  of  purity,  alcohol  is  a  colorless  liquid,  highly  inflammable,  burning  with  a 
pale  blue  flame,  very  volatile,  and  having  a  density  of  0"792  at  15'5°  C.  (G0°  F.)  {Drink- 
water.)  It  boils  at  78'4'  C.  (173'  F.)  It  has  never  yet  been  solidified,  and  the  density  of 
its  vapor  is  1-6133. 

Anhydrous  alcohol  is  composed  by  weight  of  52-18  carbon,  13-04  hydrogen,  and  34"78 
of  oxygen.  It  has  for  its  symbol  G*  H"  0"  =  C*  ff  0  -j-  HO,  or  hydrated  oxide  of  ethylo. 
It  has  a  powerful  affinity  for  water,  removing  the  water  from  moist  substances  with  which 
it  is  brought  in  contact.  In  consequence  of  this  propei'ty,  it  attracts  water  from  the  air, 
and  rapidly  becomes  weaker,  unless  kept  in  very  well-stopped  vessels.  In  virtue  of  its 
attraction  for  water,  alcohol  is  very  valuable  for  the  preservation  of  organic  substances,  and 
especially  of  anatomical  preparations,  in  consequence  of  its  causing  the  coagulation  of 
albuminous  substances ;  and  for  the  same  reason  it  causes  death  when  injected  into  the  veins. 

When  mixed  with  water  a  considerable  amount  of  heat  is  evolved,  and  a  remarkable 
contraction  of  volume  is  observed ;  these  effects  being  greatest  with  54  per  cent,  of  alco- 
hol and  40  of  water,  and  thence  decreasing  with  a  greater  proportion  of  water.  For  alco- 
hol which  contains  90  per  cent,  of  water,  this  condensation  amounts  to  r94  per  cent,  of 
the  volume  ;  for  80  per  cent.,  2-87  ;  for  70  per  cent.,  3'44  ;  for  60  per  cent.,  3'73  ;  for  40 
per  cent.,  3-44  ;  for  30  per  cent.,  2-72  ;  for  20  per  cent.,  1-72  ;  for  10  per  cent.,  0-72. 

Alcohol  is  prepared  absolute  for  certain  purposes,  but  the  mixtures  of  alcohol  and  water 
commonly  met  with  in  commerce  are  of  an  inferior  strength.  Those  commonly  sold  are 
•  "Rectified  Spirit,"  and  "  Proof  Spirit." 

"  Proof  Spirit "  is  defined  by  Act  of  Parliament,  58  Geo.  III.  c.  28,  to  be  "  such  as 
.shall,  at  the  temperature  of  fifty-one  degrees  of  Fahrenheit's  thermometer,  weigh  exactly 
twelve-thirteenth  parts  of  an  C(iu;il  mea.surc  of  distilled  water."  And  by  very  careful  experi- 
ment, Mr.  Drinkwater  has  determined  that  this  proofspirit  has  the  following  conqjosition : — 


Alcohol  ami  AVatcr. 

Specifle  Gravity 
at  00°  F. 

Biillcof  the  mixture  of 

100  measures  of  Alcoliol, 

and  SI -82  of  ^Yater. 

By  weight               j              By  measure. 

Alcohol            Water. 

100  4-   103-09 

49-100  -j-     50-70 

Alcohol.            Water. 
100     -f-     81-82 

-919. 

175-25 

*  Soemmering.     "Denksehriften  d.  K.  Akad.  d.  M'issonchaften  zxi  Munschen,"  1711  to  1S24. 


30 


ALCOHOL. 


Spirit  which  is  weaker  is  called  "under  proof;"  and  that  stronger,  "above  proof." 
The  origin  of  these  terms  is  as  follows : — Formerly  a  very  rude  mode  of  ascertaining  the 
strengtli  of  spirits  was  practised,  called  the  proof ;  the  spirit  was  poured  upon  gunpowder 
and  inflamed.  If,  at  the  end  of  the  combustion,  the  gunpowder  took  fire,  the  spirit  was 
said  to  be  above  or  over  proof.  But  if  the  spirit  contained  much  water,  the  powder  was 
rendered  so  moist  that  it  did  not  take  fire  :  in  which  case  the  spirit  was  said  to  be  under  or 
below  proof. 

Rectified  spirit  contains  from  54  to  64  per  cent,  of  absolute  alcohol ;  and  its  specific 
gravity  is  fixed  by  the  London  and  Edinburgh  Colleges  of  Physicians  at  0-888,  whilst  the 
Dublin  College  fixes  it  at  0.840. 

In  commerce  the  strength  of  mixtures  of  alcohol  and  water  is  stated  at  so  many 
degrees,  according  to  Sykes's  hi/droineter,  above  or  below  proof.  This  instrument  will  be 
explained  under  the  head  of  Alcoholometky. 

As  will  have  been  understood  by  the  preceding  remarks,  the  specific  gravity  or  density 
of  mixtures  of  alcohol  and  water  rises  with  the  diminution  of  the  quantity  of  alcohol  present ; 
or,  in  other  words,  with  the  amount  of  water.  And  since  the  strength  of  spirits  is  deter- 
mined by  ascertaining  their  density,  it  becomes  liighly  important  to  determine  the  precise 
ratio  of  this  increase.  This  increase  in  density,  with  the  amount  of  water,  or  diminution 
with  the  quantity  of  alcohol,  is,  however,  not  directly  proportional,  in  consequence  of  the 
contraction  of  volume  which  mixtures  of  alcohol  and  water  suffer. 

It  therefore  became  necessary  to  determine  the  density  of  mixtures  of  known  composi- 
tion, prepared  artificially.  This  has  been  done  recently  with  great  care  by  Mr.  l^-ink- 
water  ;*  and  the  following  table  by  him  is  recommended  as  one  of  the  most  accurate : 

Table  of  the  Qiiantiti/  of  Alcohol,  by  WEicni,  contained  in  Mixtures  of  Alcohol  and 
Water  of  the  followincj  Specific  Gravities  : — 


Specific 

Gravity  at 

60°  F. 

Alcohol,' 

per     1 

cent,  by' 

weight. 

Specific 
Gravity 
at  60°  F. 

Alcohol, 

per 
cent,  by 
weight. 

Specific 
Gravity 
at  CO"  F. 

Alcohol,'    c 
per     1    ( 
cent,  by 
weight.  1  "■ 

peciflc 

Jravity 

60°  F. 

Alcohol,' 

per      1 

cent,  by 

weight. 

Specific 
Gravity 
at  60°  F. 

Alcohol, 
per  cent. 

by         1 
weight,     1 

1-0000 

0^00 

•9967 

1^78 

•9934 

s-e,i 

9901 

5^70 

•9SC9 

7^85 

•9999 

0^05 

•9966 

r83 

•9933 

3-73 

9900 

5-77 

•9868 

7^92 

•9998 

0-11 

•99G5 

i-8d 

•9932 

3-78 

9899 

5^83 

•98G7 

7^99 

•9907 

0^16 

•99G4 

1^94 

•9931 

3-84 

9898 

6-89 

•98C6 

8-06 

•9996 

0-21 

•99G3 

1-99 

•9980 

3^90 

9897 

5^96 

•9865 

S^13 

•9995 

0-26 

•99G2 

2^05 

•9929 

3^96 

9896 

G-02 

•9864 

8-20      i 

•9994 

0^32 

•99G1 

211 

•9928 

4^02 

9895 

6-09 

•9SG3 

8^27 

•9993 

0^37 

•99G0 

2-17 

•9927 

4-08 

9894 

6-15 

•98G2 

8^34 

-9992 

0-42 

•9959 

2^22 

•992G 

4-14 

9893 

G-22 

•98G1 

8^41 

•9991 

0^47 

•9958 

2^28 

•9925 

4^20 

9892 

0-29 

•98G0 

8-48 

-9990 

0-53 

•9957 

2-34 

•9924 

4^27 

9891 

6-85 

•9859 

8^55 

•9989 

0^58 

•9956 

2^39 

•9923 

4-33 

9890 

G-42 

•9858 

8^62 

•9988 

0^04 

•9955 

2-45 

•9922 

'4-39 

9889 

6-49 

•9857 

8^70 

-9987 

0-G9 

•9954 

2^51 

•9921 

4^45 

9888 

G-55 

•9856 

8^77 

•998G 

0^74 

•9953 

2-57 

•9920 

4^51 

9887 

6-62 

•9855 

8-84 

•9985 

O^SO 

•9952 

2-62 

•9919 

4^57 

9886 

6-69 

•9854 

8^91 

•9984 

0^85 

•9951 

2^68 

•9918 

4-64 

9885 

675 

•9853 

8^98 

•9983 

©•91 

•9950 

2^74 

•9917 

4^70 

9884 

G-82 

•9852 

9^05 

•9982 

0-96 

•9949 

2^79 

•991G 

4-76 

9883 

6-89 

•9851 

9-12 

•9981 

1-02 

•9948 

2-85 

•9915 

4^82 

9882 

6-95 

•9850 

9-20 

•9980 

1^07 

•9947 

2-91 

•9914 

4^88 

9881 

7-02 

•9849 

9-27 

•9979 

112 

•994G 

2-97 

•9913 

4-94 

9880 

7-09 

•9848 

9-34 

•9978 

I^IS 

•9945 

3-02 

•9912 

5^01 

9879 

7-lG 

•9847 

9^41 

•9977 

1-23 

•9944 

3-08 

•9911 

5-07 

9878 

7-23 

•9846 

9^49 

•9976 

1-29 

•9943 

3-14 

•9910 

6-13 

9S77 

7-80 

-9845 

9^56 

•9975 

1^34 

•9942 

3-20 

•9909 

5-20 

9876 

7-37 

-9844 

9^C3 

•9974 

r40 

•9941 

3-26 

•9908 

5-26 

9875 

7-43 

•9843 

9^70 

•9973 

1-45 

•9940 

3-32 

•9907 

5^32 

9874 

7-50 

•9842 

9-78 

•9972 

1-51 

•9939 

3-37 

•9906 

5^39 

9873 

7-57 

•9841 

9-85 

•9971 

1^56 

■9938 

3-43 

•9905 

5^45 

9872 

7^64 

•9810 

9^92 

•9970 

1-61 

•9937 

3^49 

•9904 

5-51 

9871 

7^71 

•9P39 

9-99 

•9909 

1  -67 

•9936 

3^55 

•9903 

5-58 

9870 

7^78 

•9838 

10^07 

•0908 

1-7:! 

]   -9935 

3-61 

•9902 

5^04 

*  ;Moinoirs  of  tlio  Clioniical  Society,  vol.  iii.  p.  454. 


ALCOHOL. 


31 


The  preceding  table,  though  very  accurate  so  far  as  it  goes,  is  not  sufficiently  extensive 
for  practical  purposes,  only  going,  iu  fiict,  from  G  to  10  per  cent,  of  alcohol ;  the  table  of 
Tralle's  (below)  extends  to  50  per  cent,  of  absolute  alcohol. 

Moreover,  Drinkwater's  table  has  the  (practical)  disadvantage  (though  scientifically  more 
correct  and  useful)  of  stating  the  percentage  by  weight ;  whereas,  in  Tralle's  table,  it  is  giveji 
by  volume.  And  since  liquors  are  vended  by  measure,  and  not  by  weight,  the  centesimal 
amount  by  volume  is  usually  preferred.  But  as  the  bulk  of  liquids  generally,  and  par- 
ticularly that  of  alcohol,  is  increased  by  heat,  it  is  necessary  that  the  statement  of  the  den- 
sity iu  a  certain  volume  should  have  reference  to  some  normal  temperature.  In  the 
construction  of  Tralle's  table  the  temperature  of  the  liquids  was  CO^  F.  ;  and,  of  course,  in 
using  it,  it  is  necessary  that  the  density  should  be  observed  at  that  temperature. 

In  order  to  convert  the  statement  of  the  composition  by  volume  into  the  content  by 
weight,  it  is  only  necessary  to  multiply  the  percentage  of  alcohol  by  volume  by  the  specific 
gravity  of  absolute  alcohol,  and  then  divide  by  the  specific  gravity  of  the  liquid. 


Tralle's  Table  of  the  Composition,  by  volume,  of  Mixtures  of  Alcohol  and  Water  of 

different  Densities. 


Per- 
centage 
of 

Specific 

Differ- 
ence of 

Per- 
centage 

Specific 

Differ- 
ence of 

Per- 

centaire 

!  Alcohol 
1      by 
volume. 

Specific 

1 

Differ- 
ence of 

Alcohol 

by 
volume. 

Gravity  at 
60'  F. 

the  spe- 
cific gra- 
vities. 

Alcohol 

by 
volume. 

Gravity  at 
60°  F. 

the  spe- 
cific gra- 
vities. 

Gravity  at 
60°  F. 

the  spe- 
cific gra- 
vities. 

0 

0-9991 

34 

0-9596 

13 

68 

0-8941 

24 

1 

0-9976 

15 

35 

0-9583 

13 

69 

0-8917 

24 

2 

0-9961 

15 

36 

0-9570 

13 

70 

0-8892 

25 

3 

0-9947 

14 

37 

0-9556 

14 

71 

0-8867 

25 

4 

0-9933 

14 

38 

0-9541 

15 

72 

0-8842 

25 

5 

0-9919 

14 

39 

0-9526 

15 

73 

0-8817 

25 

6 

0-9906 

13 

40 

0-9510 

16 

►  '?4 

0-8791 

26 

7 

0-9893 

13 

41 

0-9494 

16 

75 

0-8765 

26 

8 

0-9881 

12 

42 

0-9478 

16 

76 

0-8739 

26 

9 

0-9869 

12 

43 

0-9461 

17 

77 

0-8712 

27 

10 

0-9857 

12 

44 

0-9444 

17 

78 

0-8685 

27 

11 

0-9845 

12 

45 

0-9427 

17 

79 

0-8658 

27 

12 

0-9834 

11 

46 

0-9409 

18 

80 

0-8631 

27 

13 

0-9823 

11 

47 

0-9391 

18 

81 

0-8603 

28 

14 

0-9812 

11 

48 

0-9373 

18 

82 

0-8575 

28 

15 

0-9802 

10 

49 

0-9354 

19 

83 

0-8547 

28 

16 

0-9791 

11 

50 

0-9335 

19 

84 

0-8518      . 

29 

17 

0-9781 

10 

51 

0-9315 

20 

85 

0-8488 

30 

18 

0-9771 

10 

52 

0-9295 

20 

86 

0-8458 

30 

19 

0-9761 

10 

53 

0-9275 

20 

87 

0-8428 

30 

20 

0-9751 

10 

54 

0-9254 

21 

88 

0-8397 

31 

21 

0-9741 

10 

55 

0-9234 

20 

89 

0-8365 

32 

22 

0-9731 

10 

56 

0-9213 

21 

90 

0-8332 

33 

23 

0-9720 

11 

57 

0-9192 

21 

91 

0-8299 

83 

24 

0-9710 

10 

58 

0-9170 

22 

92 

0-8265 

34 

25 

0-9700 

10 

59 

0-9148 

22 

93 

0-8230 

35 

26 

0-9689 

11 

60 

0-9126 

22 

94 

0-8194 

36 

27 

0-9679 

10 

61 

0-9104 

22 

95 

0-8157 

37 

28 

0-9668 

11 

62 

0-9082 

22     i 

96 

0-8118 

39 

29 

0-9657 

11 

63 

0-9059 

23 

97 

0-8077 

41 

30 

0-9646 

11 

64 

0-9036 

23     ; 

98 

0-8034 

43 

31 

0-9634 

12 

65 

0-9013 

23 

99 

0-7988 

46 

32 

0-9622 

12 

66- 

0-8989 

24 

100 

0-7939 

49 

33 

0-9609 

13 

67 

0-8965 

24 

In  order,  however,  to  employ  this  table  for  ascertaining  the  strcmith  of  mixtures  of 
alcohol  and  water  of  different  "densities  (which  is  the  practical  use  of  such  tables),  it  is 
absolutely  necessary  that  the  determination  of  the  density  .should  be  performed  at  an  inva- 
riable temperature,— viz.  60^  F.  The  metliods  of  detcrniining  the  density  will  be  hereafter 
described  ;  but  it  is  obvious  that  practically  the  experiment  cannot  be  conveniently  made  at 
any  fixed  temperature,  but  must  be  performed  at  that  of  the  atmosphere. 


32 


ALCOHOL. 


The  boiling  point  of  mixtures  of  alcohol  and  water  likewise  differs  with  the  stcngth  of 
such  mixtures. 

According  to  Gay-Lussac,  absolute  alcohol  boils  at  '78-4°  C.  (173'  F.)  under  a  pressure  of 
TOO  vdUiinetres  (the  mi llimetre  being  0-03937  English  inches).  When  mixed  with  water, 
of  course  its  boiling  point  rises  in  proportion  to  the  quantity  of  water  present,  as  is  the  case 
in  o-eneral  with  mixtures  of  two  fluids  of  greater  and  less  volatility.  A  mixture  of  alcohol 
and  water,  however,  presents  this  anomaly,  according  to  Soemmering :  when  the  mixture 
contains  less  than  six  per  cent,  of  alcohol,  those  portions  which  first  pass  off  are  saturated 
with  water,  and  the  alcoholic  solution  in  the  retort  becomes  richer,  till  absolute  alcohol 
passes  over ;  but  when  the  mixture  contains  more  than  six  per  cent,  of  water,  the  boiling 
point  rises,  and  the  quantity  of  alcohol  in  the  distillate  steadily  diminishes  as  the  distillation 
proceeds. 

According  to  Groning's  researches,  the  following  temperatures  of  the  alcoholic  vapors 
correspond  to  the  accompanying  contents  of  alcohol  in  percentage  of  volume  which  are 
disengaged  in  the  boiling  of  the  spirituous  liquid. 


Alcoholic  con- 

Alcoholic con- 

Alcoholic con- 

Alcoholic con- 

Temperature. 

tent  of  the 

tent  of  tlie 

Temperature. 

tent  of  the 

tent  of  the 

vapor. 

boiling  liquid. 

vapor. 

boiling  liquid. 

Fahr.  170-0 

93 

92 

Fahr.  189-8 

71 

20 

171-8 

92 

90 

192-0 

68 

18 

172 

91 

85 

164 

66 

15 

172-8 

90^ 

80 

196-4 

61 

12 

174 

90 

70 

198-6 

55 

10 

174-6 

89 

70 

201 

50 

7 

176 

87 

65 

203 

42 

5 

178-3 

85 

50 

205-4 

36 

3 

180-8 

8-2 

40 

207-7 

28 

2 

183 

80 

85 

210 

13 

1 

185 

78 

80 

212 

0 

0 

187-4 

76         * 

25 

Griming  undertook  this  investigation  in  order  to  employ  the  thermometer  as  an  alcoho- 
lometer in  the  distillation  of  spirits ;  for  which  purpose  he  thrust  the  bulb  of  the  thermom- 
eter through  a  cork  inserted  into  a  tube  fixed  in  the  capital  of  the  still.  The  state  of  the 
barometer 'ought  also  to  be  considered  in  making  comparative  experiments  of  this  kind. 
Since,  by  this  method,  the  alcoholic  content  may  be  compared  with  the  temperature  of  the 
vapor  that  passes  over  at  any  time,  so,  also,  the  contents  of  the  whole  distillation  may  be 
found  approximately  ;  and  the  method  serves  as  a  convenient  means  of  making  continual 
observations  on  the  progress  of  the  distillation. 

Density  of  the  Vapor. — One  volume  of  alcohol  yields  488-3  volumes  of  vapor  at  212° 
F.  The  specific  gravity  of  the  vapor,  taking  air  as  unity,  was  found  by  Gay-Lussac  to  be 
1-6133.     [Its  vapor-density,  referred  to  hydrogen,  as  unity,  is  13-3605  V] 

Spirituous  vapor  passed  through  an  ignited  tube  of  glass  or  porcelain  is  converted  into 
carbonic  oxide,  water,  hydrogen,  carburetted  hydrogen,  defiant  gas,  naphthaline,  empyrcu- 
matic  oil,  and  carbon  ;  according  to  the  degree  of  heat  and  nature  of  the  tube,  these 
products  vary.  Anhydrous  alcohol  is  a  non-conductor  of  electricity,  but  is  decomposed  by 
a  powerful  voltaic  battery.  Alcohol  burns  in  the  air  with  a  blue  flame  into  carbonic  acid 
and  water;  the  water  being  heavier  than  the  spirit,  because  46  parts  of  alcohol  contain  6 
of  hydrogen,  which  form  54  of  water.  In  oxygen  the  combustion  is  accompanied  with 
great  heal,  and  this  flame,  directed  through  a  small  tube,  powerfully  ignites  bodies  exposed 
to  it. 

Platinum  in  a  finely  divided  state  has  the  property  of  determining  the  combination  of 
alcohol  with  the  oxygen  of  the  air  in  a  remarkable  manner.  A  ball  of  spongy  platinum, 
placed  slightly  above  the  wick  of  a  lamp,  fed  by  spirit,  and  communicating  with  the  wick  by 
a  platinum  wiVe,  when  once  heated,  keeps  at  a  red  heat,  gradually  burning  the  si)irit.  This 
has  been  applied  in  the  construction  of  the  so-called  "  philosophical  pastilles ;  "  cau-de- 
colosne  or  other  perfumed  spirit  being  thus  made  to  diffuse  itself  in  a  room. 

Mr.  Gill  has  also  practically  applied  this  iu  the  construction  of  an  alcohol  lamp  without 
flame. 

A  coil  of  platinum  wire,  of  about  the  one-hundreth  part  of  an  inch  in  thickness,  is  coiled 
partlv  round  the  cotton  wick  of  a  spirit  lamp,  and  partly  above  it,  and  the  lamp  lighted  to 
heat  the  wire  to  redness  ;  on  the  flame  being  extinguished,  the  alcohol  vapor  keeps  the  wire 
red  hot  for  any  length  of  time,  so  as  to  be  in  constant  readinc'^s  to  ignite  a  match,  for 
example.  This'  lamp  affords  sufficient  light  to  show  the  hour  by  a  watch  in  the  night,  with 
a  very  small  consumption  of  spirit. 


ALCOHOL.  33 

This  property  of  condensing  oxygen,  and  thus  causing  the  union  of  it  with  combustible 
bodies,  is  not  confined  to  platinum,  but  is  possessed,  though  in  a  less  degree,  by  other 
porous  bodies.  If  we  moisten  sand  in  a  capsule  with  absolute  alcohol,  and  cover  it  with 
previously  heated  nickel  powder,  protoxide  of  nickle,  cobalt  powder,  protoxide  of  cobalt, 
protoxide  of  uranium,  or  oxide  of  tin  (these  six  bodies  being  procured  by  ignition  of  their 
oxalates  in  a  crucible),  or  finely  powdered  peroxide  of  manganese,  combustion  takes  place, 
and  continues  so  long  as  the  spirituous  vapor  lasts. 

Solvent  Power. — One  of  the  properties  of  alcohol  most  valuable  in  the  arts  is  its  solvent 
power. 

It  dissolves  gases  to  a  very  considerable  extent,  which  gases,  if  they  do  not  enter  into  com- 
binations with  the  alcohol,  or  act  chemically  upon  it,  are  expelled  again  on  boiling  the  alcohol. 

Several  salts,  especially  the  deliquescent,  are  dissolved  by  it,  and  some  of  them  give  a 
color  to  its  flame  ;  thus  the  solutions  of  the  salts  of  strontia  in  alcohol  burn  with  a  crimson 
fiame,  those  of  copper  and  borax  with  a  ffreen  one,  lime  a  reddish,  and  baryta  with  a  yellow 
flame. 

This  solvent  power  is,  however,  most  remarkable  in  its  action  upon  resins,  ethers,  essen- 
tial oils,  fatty  bodies,  alkaloids,  as  well  as  many  organic  acids.  In  a  similar  way  it  dissolves 
iodine,  bromine,  and  in  small  quantities  sulphur  and  phosphorus.  In  general  it  may  be  said 
to  be  an  excellent  solvent  for  most  hydrogenized  organic  substances. 

In  consequence  of  this  property  it  is  most  extensively  used  in  the  chemical  arts ;  c.  g.  for 
the  solution  of  gum-resins,  &c.,  in  the  manufacture  of  varnishes ;  in  pharmacy,  for  the 
separating  of  the  active  principles  of  plants,  in  the  preparation  of  tinctures.  It  is  also  em- 
ployed in  the  formation  of  chloroform,  ether,  spirits  of  nitre,  &c. 

ifethylated  Spirit.— It  was,  therefore,  for  a  long  time  a  great  desideratum  for  the 
manufacturer  to  obtain  spirit  free  from  duty.  The  Government,  feeling  the  necessity  for 
this,  have  sanctioned  the  sale  of  spirit  which  has  been  flavored  with  methyl-alcohol,  so  as  to 
render  it  unpalatable,  free  of  duty  under  the  name  of  "  methylated  spirit.^'  This  methylated 
spirit  can  now  be  obtained,  in  large  quantities  only,  and  by  giving  suitable  security  to  the 
Board  of  Inland  Revenue  of  its  employment  for  manufacturing  purposes  only,  and  must 
prove  of  great  value  to  those  manufacturers  who  are  large  consumers. 

Professors  Graham,  Hoffmann,  and  Redwood,  in  their  "  Report  on  the  Supply  of  Spirit 
of  AVine,  free  of  duty,  for  use  in  the  Arts  and  Manufactures,"  addressed  to  the  Chairman 
of  the  Board  of  Inland  Revenue,  came  to  the  following  conclusions  : — 

"  From  the  results  of  this  inquiry,  it  has  appeared  that  means  exist  by  which  spirit  of 
wine,  produced  in  the  usual  way,  may  be  rendered  unfit  for  human  consumption,  as  a 
beverage,  without  materially  impairing  it  for  the  greater  number  of  the  more  valual)lc  pur- 
poses in  the  arts  to  which  spirit  is  usually  applied.  To  spirit  of  wine,  of  not  less  strength 
than  corresponds  to  density  0'830,  it  is  proposed  to  make  an  addition  of  10  per  cent,  of 
purified  wood  naphtha  {wood  or  methylic  spirit),  and  to  issue  this  mixed  spirit  for  consump- 
tion, duty  free,  under  the  name  of  ifethylated  Spirit.  It  has  been  shown  that  methylated 
spirit  resists  any  process  for  its  purification  ;  the  removal  of  the  substance  added  to  the  spirit 
of  wine  being  not  only  difficult,  but,  to  all  appearance,  impossible ;  and  further,  that  no 
danger  is  to  be  apprehended  of  the  methylated  spirit  being  ever  compounded  so  as  to  make 
it  palatable.  .  .  It  may  be  found  safe  to  reduce  eventually  the  proportion  of  the  mixing 
ingredient  to  5  per  cent.,  or  even  a  smaller  proportion,  although  it  has  been  recommended 
to  begin  with  the  larger  proportion  of  10  per  cent." 

And  further,  the  authors  justly  remark : — "  The  command  of  alcohol  at  a  low  price 
is  sure  to  suggest  a  multitude  of  improved  processes,  and  of  novel  applications,  which  can 
scarcely  be  anticipated  at  the  present  moment.  It  will  be  felt  far  beyond  the  limited  range 
of  the  trades  now  more  immediately  concerned  in  the  consumption  of  spirits ;  like  the 
repeal  of  the  duty  on  salt,  it  will  at  once  most  vitally  affect  the  chemical  arts,  and  cannot 
fail,  ultimately,  to  exert  a  beneficial  influence  upon  many  branches  of  industr)'." 

And  in  additional  observations;  added  subsequently  to  their  original  report,  the  chem- 
ists above  named  recommend  the  following  restriction  upon  the  sale  of  the  methylated 
spirit : — "  That  the  methylated  spirit  should  be  issued  by  agents  duly  authorized  by  the 
Board  of  Inland  Revenue,  to  none  but  manufacturers,  who  should  themselves  consume  it ; 
and  that  application  should  always  be  made  for  it  according  to  a  recognized  form,  in  which, 
besides  the  quantity  wanted,  the  applicant  should  state  the  use  to  which  it  is  to  be  applied, 
and  undertake  that  it  should  be  applied  for  that  purpose  only.  The  manufacturer  might  be 
permitted  to  retail  varnishes  and  other  products  containing  the  methylated  spirit,  but  not 
the  methylated  spirit  itself,  in  an  unaltered  state."  They  recommend  that  the  methylated 
spirit  should  not  be  made  with  the  ordinary  crude,  very  impure  wood  naphtha,  since  this 
could  not  be  advantageously  used  as  a  solvent  for  resins  by  hatters  and  varnish-makers,  as 
the  less  volatile  parts  of  the  naphtha  would  be  retained  by  the  resins  after  the  spirit  had 
evaporated,  and  the  quality  of  the  resin  would  be  thus  impaired.  If,  however,  the  methy- 
lated spirit  be  originally  prepared  with  the  crude  wood  naphtha,  it  may  be  purified  by  a 
simple  distillation  from  10  per  cent,  of  potash. 
Vol..  III.—:] 


34  ALCOHOLOMETRY. 

It  appears  that  the  boon  thus  afforded  to  the  manufacturing  community  of  obtaining 
spirit  dutyfree  has  been  acknowledged  and  appreciated  ;  and  now  for  most  purposes,  where 
the  small  quantity  of  wood-spirit  does  not  interfere,  the  methylated  spirit  is  generally  used. 

It  appears  that  even  ether  and  chlorofonn,  which  one  would  expect  to  derive  an  un- 
pleasant Havor  from  the  wood-spirit,  are  now  made  of  a  quality  quite  unobjectionable  from 
the  methylated  spirit ;  but  care  should  be  taken,  especially  in  the  preparation  of  medicinal 
compounds,  not  to  extend  the  employment  of  the  methylated  spirit  beyond  its  justifiable 
limits,  lest  so  useful  an  article  should  get  into  disrepute.*  Methylated  spirit  can  be  pro- 
cured also  in  small  quantities  from  the  wholesale  dealers,  containing  in  solution  1  oz.  to  the 
gallon  of  shellac,  under  the  name  of  "  finish." 

Alcoholates. — Graham  has  shown  that  alcohol  forms  crystallizable  compounds  with 
several  salts.  These  bodies,  which  he  calls  "  Alcoholates,''^  arc  in  general  rather  unstable 
combinations,  and  almost  always  decomposed  by  water.  Among  the  best  known  arc  the 
following : — 

Alcoholutc  of  chloride  of  calcium  -         -         -  2  C*IPO=,  Ca  CI 

of  zinc  -         -         -  C^H'^O^ZnCl 

bichloride  of  tin  ...  CH^O",  Tn  CI 

"              nitrate  of  magnesia  ...  3  C*H'0%  Mg  0,  NOb 

ALCOHOLOMETRY,  or  ALCOOMETRY.  Determination  of  the  Strength  of  Mixtures 
of  Alcohol  and  Water.  Since  the  commercial  value  of  the  alcoholic  liquors,  commonly 
called  "  spirits,"  is  determined  by  the  amount  of  pure  or  absolute  alcohol  present  in  them, 
it  is  evident  that  a  ready  and  accurate  means  of  determining  this  point  is  of  the  highest 
importance  to  all  persons  engaged  in  trade  in  such  articles. 

If  the  mixture  contain  nothing  but  alcohol  and  water,  it  is  only  necessary  to  determine 
the  density  or  specific  gravity  of  such  a  mixture  ;  if,  however,  it  contain  saccharine  matters, 
coloring  principles,  &c.,  as  is  the  case  with  wine,  beer,  &c.,  other  processes  become  neces- 
sary, which  will  be  fully  discussed  hereafter. 

The  determination  of  the  specific  gravity  of  spirit,  as  of  most  other  liquids,  may  be 
effected,  with  perhaps  greater  accuracy  than  by  any  other  process,  by  means  of  a  stoppered 
specific  gravity  bottle.  If  the  bottle  be  of  such  a  size  as  exactly  to  hold  1,000  grains  of 
distilled  water  at  C0°  F.,  it  is  only  necessary  to  weigh  it  full  of  the  spirit  at  the  same  tem- 
perature, when  (the  weight  of  the  bottle  being  known)  the  specific  gravity  is  obtained  by  a 
very  simple  calculation.    See  Specific  Gravity. 

This  process,  though  very  accurate,  is  somewhat  trouljlesome,  especially  to  persons 
unaccustomed  to  accurate  chemical  experiments,  and  it  involves  the  possession  of  a  delicate 
balance.  The  necessity  for  this  is  however  obviated  by  the  employment  of  one  of  the  many 
modifications  of  the  common  hydrometer.  This  is  a  floating  instrmnent,  the  use  of  which 
depends  upon  the  principle,  that  a  solid  body  immersed  into  a  fluid  is  buoyed  upwards  with 
a  force  equal  to  the  weight  of  the  fluid  which  it  displaces,  i.  e.  to  its  own  bulk  of  the  fluid  ; 
consequently,  the  denser  the  spirituous  mixture,  or  the  less  alcohol  it  contains,  the  higher 
will  the  instrument  stand  in  the  liquid  ;  and  the  less  dense,  or  the  more  spirit  it  contains, 
the  lower  will  the  apparatus  sink  into  it. 

There  are  two  classes  of  hydrometers :  1st.  Those  which  are  always  immersed  in  the 
fluid  to  the  same  depth,  and  to  which  weights  are  added  to  adjust  the  instrument  to  the 
density  of  any  particular  fluid.  Of  this  kind  are  Fahrenheit's,  Nicholson's,  and  Guyton  de 
Morvoau's  hydrometers. 

2d.  Those  which  are  always  used  with  the  same  weight,  but  which  sink  into  the  liquids 
to  be  tried,  to  different  depths,  according  to  the  density  of  the  fluid.  Of  this  class  are  most 
of  the  common  glass  hydrometers,  such  as  Beaumc's,  Curteis's,  Gay-Lussac's,  Twaddle's,  &c. 

Sykes's  and  Dicas's  combine  both  principles.     See  Hydrometers. 

Sykcs's  hydrometer,  or  alcoholometer,  is  the  one  employed  by  the  Board  of  Excise,  and 
therefore  the  one  most  extensively  used  in  this  country. 

This  instrument  docs  not  immediately  indicate  the  density  or  the  percentage  of  absolute 
alcohol,  but  the  degree  above  or  beloio  proof— iha  meaning  of  which  has  been  before 
detailed ;  (p.  30.) 

It  consists  of  a  spherical  ball  or  float,  fr,  wi^li  nn  upper  and  lower  stem  of  brass,  b  and  c. 
The  upper  stem  is  graduated  into  ten  principal  divisions,  which  are  each  subdivided  into 
five  parts.  The  lower  stem,  f,  is  made  conical,  and  has  a  loaded  bulb  at  its  extremity. 
Tliere  are  nine  movable  weights,  numbered  respectively  by  tens  from  10  to  90.  Each  of 
these  circular  weights  has  a  slit  in  it,  so  that  it  can  be  placed  on  the  conical  stem,  c.  The 
instrument  is  adjusted  so  that  it  floats  with  the  surface  of  the  fluid  coincident  with  zero  on 
the  scale  in  a  spirit  of  specific  gravity  -825  at  G0°  F.,  this  being  accounted  by  the  Excise  as 
"  standard  alcohol."     In  weaker  spirit,  which  has  therefore  a  greater  density,  the  hydrom- 

♦  Some  difference  of  opinion  appears  to  exist  whether  Chloroform  can  be  ohtnined  pure  from  me- 
thylated spirit. 


ALOOIIOLOMETRY. 


35 


cter  will  not  sink  so  low ;  and  if  the  density  bo  much  greater,  it  will  be  necessary  to  add 
one  of  the  weights  to  cause  the  entire  immersion  of  the  bulb  of  the  instrument.     Each 
weight  represents  so  many  principal  divisions  of  the  stem  as  its  number 
indicates ;  thus,    the  heaviest    weight,  marked  90,  is  equivalent  to  90  'J 

divisions  of  the  stem,  and  the  instrument,  with  the  weight  added,  floats  at 
0  in  distilled  water.  As  each  principal  division  on  the  stem  is  divided 
into  five  subdivisions,  the  instrument  has  a  range  of  500  degrees  be- 
tween the  standard  alcohol  (specific  gravity  -825)  and  water.  There  is  a 
line  on  one  of  the  side  faces  of  the  stem,  b,  near  division  1  of  the  draw- 
ing, at  which  line  the  instrument  with  the  weight  60  attached  to  it,  floats 
in  spirits  exactly  of  the  strength  of  proof,  at  a  temperature  of  51°  F. 

In  using  this  instrument,  it  is  immersed  in  the  spirit,  and  pressed  down 
by  the  hand  until  the  whole  of  the  graduated  portion  of  the  Upper  stem 
is  wet.  The  force  of  the  hand  required  to  sink  it  will  be  a  guide  to  the 
selection  of  the  proper  weight.  Having  taken  one  of  the  circular  weights 
necessary  for  the  purpose,  it  is  slipped  on  to  the  lower  conical  stem. 

The  instrument  is  again  immersed,  and  pressed  down  as  before  to  0, 
and  then  allowed  to  rise  and  settle  at  any  point.  The  eye  is  then  brought 
to  the  level  of  the  surface  of  the  spirit,  and  the  part  of  the  stem  cut  by 
the  surface  as  seen  from  below,  is  marked.  The  number  thus  indicated 
by  the  stem  is  added  to  the  number  of  the  weight,  and  the  sum  of  these, 
together  with  the  temperature  of  the  spirit,  observed  at  the  same  time  by 
means  of  a  thermometer,  enables  the  operator,  by  reference  to  a  table 
which  is  sold  to  accompany  the  instrument,  to  find  the  strength  of  the 
spirit  tested. 

These  tables  are  far  too  voluminous  to  be  quoted  here ;  and  this  is 
unnecessary,  since  the  instrument  is  never  sold  without  them. 

A  modification  of  Sykes's  hydrometer  has  been  recently  adopted  for 
testing  alcoholic  liquors,  which  is  perhaps  more  convenient,  as  the  neces- 
sity for  the  loading  weights  is  done  away  with,  the  stem  being  sufficiently 
long  not  to  require  them.  It  is  constructed  of  glass,  and  is  in  the  shape 
of  a  common  hydrometer,  the  stem  being  divided  into  degrees ;  it 
carries  a  small  spirit  thermometer  in  the  bulb,  to  which  a  scale  is  fixed,  ranging  from  SO'  to 
82"  F.  (0  to  12°  C.)  There  are  tables  supplied  with  the  hydrometer,  which  are  headed  by 
the  degrees  and  half  degrees  of  the  thermometric  scale  ;  and  the  corresponding  content 
of  spirit,  over  or  under  proof  at  the  respective  degrees  of  the  table,  is  placed  opposite  each 
degree  of  the  hydrometer.     See  Spirits,  vol.  ii. 

In  France,  Gay-Lussac's  alcoolometre  is  usually  employed.  It  is  a  common  glass 
hydrometer,  with  the  scale  on  the  stem  divided  into  100  parts  or  degrees.  The  lowest 
division,  marked  0,  denotes  the  specific  gravity  of  pure  water;  and  100,  that  of  absolute- 
alcohol,  both  at  15°  C.  (59°  F.)  The  intermediate  degrees,  of  course,  show  the  percentage 
of  absolute  alcohol  by  volume  at  15°  C. ;  and  the  instrument  is  accompanied  by  the  tables 
already  given  for  ascertaining  the  percentage  at  any  other  temperature. 

Alcoholometry  of  Liquids   containing    besides   Alcohol,    Saccharine   Matters,    Coloring 
Principles,  ^c,  such  as  Wines,  Beer,  Liqueurs,  Sfc. 

In  order  to  determine  the  proportion  of  absolute  alcohol  contained  in  wines  or  other 
mixtures  of  alcohol  and  water  with  saccharine  and  other  non-volatile  substances,  the  most 
accurate  method  consists  in  submitting  a  known  volume  of  the  liquid  to  distillation,  (in  a 
glass  retort,  for  instance  ;)  then,  by  determining  the  specific  gravity  of  the  distilled  product, 
to  ascertain  the  percentage  of  alcohol  in  this  distillate,  which  may  be  regarded  as  essentially 
a  mixture  of  pure  alcohol  and  water.  The  distillation  is  carried  on  until  the  last  portions 
have  the  gravity  of  distilled  water  ;  by  then  ascertaining  the  total  volume  of  the  distillate, 
and  with  the  knowledge  of  its  percentage  of  alcohol  and  the  volume  of  the  original  liquor 
used,  the  method  of  calculating  the  quantity  of  alcohol  present  in  the  wine,  or  other  liquor, 
is  sufficiently  obvious. 

In  carrying  out  these  distillations,  care  must  be  taken  to  prevent  the  evaporation  of  the 
spirit  from  the  distillate,  by  keeping  the  condenser  cool.  And  Frofessor  Mulder  recom- 
mends the  use  of  a  refrigerator,  consisting  of  a  glass  tube  fixed  in  the  centre  of  a  jar,  so 
tliat  it  may  be  kept  filled  with  cold  water.  The  tube  must  be  bent  at  a  riglit  angle,  and 
terminate  in  a  cylindrical  graduated  measure-glass,  shaped  like  a  bottle.* 

It  is  well  to  continue  the  distillation  until  about  two-thirds  of  the  liquid  has  passed 
over. 

This  process,  though  the  most  accurate  for  the  estimation  of  the  strength  of  alcoholic 

♦  The  Chemistry  of  Wine,  by  G.  J.  Mulder,  edited  by  II.  Bence  Jones,  M.  D. 


1 


36 


ALCOnOLOMETRY. 


liquors,  is  still  liable  to  error.  The  volatile  acids  and  ethers  pass  over  with  the  alcohol  into 
the  distillate,  and,  to  a  slight  extent,  affect  the  specific  gravity.  This  error  may  be,  to  a 
great  extent,  overcome  by  mixing  a  little  chalk  with  the  wine,  or  other  liquor,  previous  to 
distillation. 

By  this  method  Professor  Brande  made,  some  years  ago,  determinations  of  the  strength 
of  the  following  wines,  and  other  liquors  *  : — 

Proportion  of  Spirit  per  Cent,  hy  Measure. 


Lissa 

. 

average 

25-41 

Orange 

. 

average  11-26 

Raisin    - 

- 

(( 

25-12 

Elder 

. 

8-79 

Marsala 

. 

(( 

25-09 

Port  (of  7  samples) 

" 

22-96 

Cider 

average  5-21  to  9-87 

Madeira 

- 

a 

22-27 

Perry 

7-26 

Sherry  (of  4  samples)     - 

(( 

1917 

Mead 

7-32 

Tenerifie 

- 

- 

19-79 

Ale,  Burton          J 

(8-88 

Lisbon   - 

- 

18-94 

Ale,  Edinburgh    > 

average  6"87    \  6-20 

Malaga  - 

- 

18-94 

Ale,  Dorchester   ) 

(5-55 

Bucellas 

- 

18-49 

Brown  Stout 

. 

6-80 

Cape  Madeira 

average 

20-51 

London  Porter    - 

- 

average     4-20 

Roussillon 

" 

19.00 

London  Small  Beer 

- 

-       "         1-28 

Claret    - 

" 

15-10 

Sauterne 

(( 

14-22 

Brandy 

- 

-       "       53-39 

Burgundy 

(1 

14-57 

Rum 

. 

-       "       53-68 

Hock      - 

(( 

12  08 

Gin 

. 

-       "       57-60 

Tent       - 

i( 

13-30 

Scotch  Whiskey 

- 

-       "       54-32 

Champagne    - 

ii 

12-61 

Irish  Whiskey     - 

- 

-       "       53-90 

Gooseberry     - 

(1 

11-84 

Port  (1834) 

22-46 

Port  (best) 

Sherry  (Montilla) 

19-95 

Marcobrunner 

Madeira 

22-40 

Champagne  (1st) 

Claret  (Haut  Brion) 

10-0 

Champagne  (2d) 

Chambertin 

11-7 

Home  Ale 

Sherry  (low  quality) 

20-7 

Export  Ale 

Sherry  (brown) 

23-1 

Strong  Ale 

Amontillado 

20-5 

Stout 

Mansanilla 

14.4 

Porter      - 

The  following  results  were  obtained  by  the  writer  more  recently  by  this  process, 
(1854.) 

Percentage  of  Alcohol  by  Volume. 

20-2 
8-3 
12-12 
10-85 
6-4 
6-4 
9-0 
5-7 
4-18 

M.  I'Abbe  Brossard-Vidal,  of  Toulonf ,  has  proposed  to  estimate  the  strength  of  alcoholic 
liquors  by  determining  their  boiling  point.  Since  water  boils  at  100 '  C.  (212' F.),  and 
absolute  alcohol  at  78-4^  (173°  F.),  it  is  evident  that  a  mixture  of  water  and  alcohol  will 
have  a  higher  boiling  point  the  larger  the  quantity  of  water  present  in  it.  This  method  is 
even  applicable  to  mixtures  containing  other  bodies  in  solution  besides  spirit  and  water, 
since  it  has  been  sho\vn  that  sugar  and  salts,  when  present,  (in  moderate  quantities,)  have 
only  a  very  trifling  effect  in  raising  the  boiling  point ;  and  the  process  has  the  great  advan- 
tage of  facility  and  rapidity  of  execution,  though,  of  course,  not  comparable  to  the  method 
by  distillation,  for  accuracy. 

Mr.  Field's  patent  (1847)  alcoholometer  is  likewise  founded  upon  the  same  principle. 
The  instrument  was  subsequently  improved  by  Dr.  Urc. 

The  apparatus  consists  simply  of  a  spirit-lamp  placed  under  a  little  boiler  containing  the 
alcoholic  liquor,  into  which  fits  a  thermometer  of  very  fine  bore. 

When  the  lifjuor  is  stronger  than  proof-spirit,  the  variation  in  the  boiling  point  is  so 
small  that  an  accurate  result  cannot  possibly  be  obtained  ;  and,  in  fact,  .spirit  approaching 
this  strength  should  be  diluted  with  an  equal  volume  of  water  before  submitting  it  to  ebulli- 
tion, and  then  the  result  doubled. 

Another  source  of  error  is  the  elevation  of  the  boiling  point,  when  the  liquor  is  kept 
heated  for  any  length  of  time  ;  it  is,  however,  nearly  obviated  by  the  addition  of  common 
salt  to  the  solution  in  the  boiler  of  the  apparatus,  in  the  proportion  of  35  or  40  grains.  In 
order  to  correct  the  difference  arising  from  higher  or  lower  pressure  of  the  atmosphere,  the 
scale  on  which  the  thermometric  and  other  divisions  are  marked  is  made  movable  up  and 

*  Brando's  Manual  of  Chemi.stry ;  also  Philosophical  Trans.,  ISll.         +  Comptes  Ecndus,  xxvii.  374. 


ALOOHOLOMETRY. 


37 


down  the  thermometer  tube  ;  and  every  time,  before  commencing  a  set  of  experiments,  a 
preliminary  experiment  is  made  of  boiling  some  pure  distilled  water  in  the  apparatus,  and 
the  zero  point  on  the  scale  (which  indicetes  the  boiling  point  of  water)  is  adjusted  at  the 
level  of  the  surface  of  the  mercury. 

But  even  when  performed  with  the  utmost  care,  this  process  is  still  liable  to  very 
considerable  errors,  for  it  is  extremely  difficult  to  observe  the  boiling  point  to  within  a 
degree  ;  and  after  all,  the  fixed  ingredients  present  undoubtedly  do  seriously  raise  the  boil- 
in'^  point  of  the  mixture — in  fact,  to  the  extent  of  from  half  to  a  whole  degree,  according  to 
the  amount  present. 

Silbermannh  Alethod. — M.  Silbermann*  has  proposed  another  method  of  estimating  the 
streno-th  of  alcoholic  liquors,  based  upon  their  expansion  by  heat.     It  is  well  known  that, 
between  zero  and  100°  C.  (212°  F.),  the  dilatation  of  alcohol  is  triple  that 
of  water,  and  this  difference  of  expansion  is  even  greater  between  25°  C.  g 

(77°  F.)  and  50°  C.  (122°  F.) ;  it  is  evident,  therefore,  that  the  expansion  c£?> 

between  these  two  temperatures  becomes  a  measure  of  the  amount  of  al- 
cohol present  in  any  mixture.  The  presence  of  salts  and  organic  sub- 
stances, such  as  sugar,  coloring,  and  extractive  matters,  in  solution  or 
suspension  in  the  liquid,  is  said  not  materially  to  affect  the  accuracy  of 
the  result ;  and  M.  Silbermann  has  devised  an  apparatus  for  applying  this 
principle,  in  a  ready  and  expeditious  manner,  to  the  estimation  of  the 
strength  of  alcoholic  liquors.  The  instrument  may  be  obtained  of  the 
philosophical  instrument-makers  of  London  and  of  Liverpool. 

It  consists  of  a  brass  plate,  on  which  are  fixed — 1st,  An  ordinary  mer- 
curial thermometer  graduated  from  22°  to  50°  0.  (77°  to  122°  F.),  these 
being  the  working  temperatures  of  the  dilatatometer ;  and  2dly,  the 
dilatatometer  itself,  which  consists  of  a  glass  pipette,  open  at  both  ends, 
and  of  the  shape  shown  in  the  figure.  A  valve  of  cork  or  india-rubber 
closes  the  tapering  end,  a,  which  valve  is  attached  to  a  rod,  b  b,  fastened 
to  the  supporting  plate,  and  connected  with  a  spring,  w,  by  which  the 
lower  orifice  of  the  pipette  can  be  opened  or  closed  at  will.  The  pipette 
is  filled,  exactly  up  to  the  zero  point,  with  the  mixture  to  be  examined — 
this  being  accomplished  by  the  aid  of  a  piston  working  tightly  in  the  long 
and  wide  limb  of  the  pipette ;  the  action  of  which  serves  also  another 
valuable  purpose,  viz.,  that  of  drawing  any  bubbles  of  air  out  of  the 
liquid.  By  now  observing  the  dilatation  of  the  column  of  liquid  when  the 
temperature  of  the  whole  apparatus  is  raised,  by  immersion  in  a  water-bath, 
from  25°  to  50°,  the  coefficient  of  expansion  of  the  liquid  is  obtained, 
and  hence  the  proportion  of  alcohol — the  instrument  being,  in  fact,  so 
graduated,  by  experiments  previously  made  upon  mixtures  of  known 
composition,  as  to  give  at  once  the  percentage  of  alcohol. 

Another  alcoholometer,  which,  like  the  former,  is  more  remarkable  for 
the  great  facility  and  expedition  with  which  approximative  results  can  be 
obtained  than  for  a  high  degree  of  accuracy,  was  invented  by  M.  Geisler, 
of  Bonn,  and  depends  upon  the  measurement  of  the  tension  of  the  vapor  of  the  liquid,  as 
indicated  by  the  height  to  which  it  raises  a  column  of  mercury. 

Geisler's   Alcoholometer. — It  consists  of  a   closed  vessel  in  which  the  alco-         9 
holic  mixture  is  raised  to  the  boiling  point,  and  the  tension  of  the  vapor  ob- 
served by  the  depression  of  a  column  of  mercury  in  one  limb  of  a  tube,  the 
indication  being  rendered  more  manifest  by  the  elevation  of  the  other  end  of  the 
column. 

The  wine  or  other  liquor  of  which  it  is  desired  to  ascertain  the  strength,  is  put 
into  the  little  flask,  f,  which,  when  completely  filled,  is  screwed  on  to  the  glass 
which  contains  mercury,  and  is  closed  by  a  stopcock  at  s.  The  entire  apparatus, 
wiiich  at  present  is  an  inverted  position,  is  now  stood  erect,  the  flask  and  lower 
extremity  of  the  tube  being  immersed  in  a  water-bath.  The  vinous  liquid  is  thus 
heated  to  a  boiling  point,  and  its  vapor  forces  the  mercury  up  into  the  long  limb 
of  the  tube.  The  instrument  having  been  graduated,  once  for  all,  by  actual  ex- 
periment, the  percentage  of  alcohol  is  read  off  at  once  on  the  stem  by  the  height 
to  which  the  mercurial  column  rises.  r 

-  To  show  how  nearly  the  results  obtained  by  this  instrument  agree  with  those 
obtained  by  the  distillation  process,  comparative  experiments  were  made  on  the  s 
same  wines  by  Dr.  Bencc  Jones,  f 


*  Comptes  Renfliis,  xxvii.  418. 

t  On  the  Acidity,  Sweotncss,  and  Strontrth  of  different  Wines,  by  II.  Bcnco  Jones,  M.  D.,  F.  R.  S., 
Proceedings  of  the  Koyal  Institution,  February,  1854 


38  ALOOHOLOMETRY. 

By  Distillation  (Mr.  "Witt)     By  Alcoholometer 
per  cent,  by  measure,      per  cent,  by  measare. 

Port,  1834, 22-46         ..  I  g'.^ 

(  20-'7 
Sherry,  Montilla,     ....  19-95         .         .  \  20-6 

(20-6 

Madeira, 22-40         .         .  -j  :^^[^ 

Haut  Brion  claret,  ....  10-0  .         .  |  jj^J 

Chambertin,       .  .  .  .  .       ll'l  .         .  "j  is-o 

(  ''l-l 
Low-quality  sherry,  .  .  .  20-7  .         .  <  Z^.^ 

Brown  sherry,    .....  23-1  .  .  A    „.„ 

Amontillado,            ....  20'5  .  .  ]  21-0 

Mansanilla,        .....  14-4:  .  .  <  ^..^ 

Port,  best, 20-2  .  .  -j  ^{'.J 

Marcobrunner,  .            .            .            .            .  8-3  .  .  ■<    „.g 

Home  ale,   .  .  .  .  .  ^^  '        '         ]    'j-1 

<    1-0 
Export  ale,         .  .  .  .  .         6-4  .         .  •<    g.g 

Strong  ale,  .....  2-0  .         .  j  ^^.g 

TabariPs  Method. — There  is  another  method  of  determining  the  alcoholic  contents  of 
mixtures,  which  especially  recommends  itself  on  account  of  its  simplicity.  The  specific 
gravity  of  the  liquor  is  first  determined,  half  its  volume  is  next  evaporated  in  the  open  air, 
sufficient  water  is  then  added  to  the  remainder  to  restore  its  original  volume,  and  the  spe- 
cific gravity  again  ascertained.  By  deducting  the  specific  gravity  before  the  expulsion  of 
the  alcohol  from  that  obtained  afterwards,  the  difference  gives  a  specific  gravity  indicating 
the  percentage  of  alcohol,  which  may  be  found  by  referring  to  Gay-Lussac's  or  one  of  the 
other  Tables.  Tabarle  has  constructed  a  peculiar  instrument  for  determining  these  specific 
gravities,  which  he  'calls  an  cenometer ;  but  they  may  be  performed  either  by  a  specific- 
gravity  bottle  or  by  a  hydrometer  in  the  usual  way. 

Of  course  this  method  cannot  be  absolutely  accurate  ;  nevertheless,  Prof.  Mulder's  ex- 
perience with  it  lias  led  him  to  prefer  it  to  any  of  the  methods  before  described,  especially 
where  a  large  number  of  samples  have  to  be  examined.  He  states  that  the  results  are 
almost  as  accurate  as  those  obtained  by  distillation.  The  evaporation  of  the  solution  may 
be  accelerated  by  conducting  hot  steam  through  it. 

Adulterations. — Absolute  alcohol  should  be  entirely  free  from  water.  This  may  be 
recognized  by  digesting  the  spirit  with  pure  anhydrous  sulphate  of  copper.  If  the  spirit 
contain  any  water,  the  white  salt  becomes  tinged  blue,  from  the  formation  of  the  blue 
hydrated  sulphate  of  copper. 

Rectified  spirit,  proof  spirit,  and  the  other  mixtures  of  pure  alcohol  and  water,  should 
be  colorless,  free  from  odor  and  taste.  If  containing  methylic  or  amylic  alcohols,  they  are 
immediately  recognized  by  one  or  other  of  these  simple  tests. 

Dr.  Ure  states,  that  if  wood  spirit  be  contained  in  alcohol,  it  may  be  detected  to  the 
greatest  minuteness  by  the  test  of  caustic  potash,  a  little  of  which,  in  powder,  causing  wood 
spirit  to  become  speedily  yellow  and  brown,  while  it  gives  no  tint  to  alcohol.  Thus  1  per 
cent,  of  wood  spirit  may  be  discovered  in  any  sample  of  spirits  of  wine. 

The  admixture  with  a  larger  proportion  than  the  due  amount  of  water  is  of  course  de- 
termined by  estimating  the  percentage  of  absolute  alcohol  by  one  or  other  of  the  several 
methods  just  described  in  detail. 

The  adulterations  and  sophistications  to  which  the  various  spirits  known  as  rum,  brandy 
whiskey,  gin,  &c.,  are  subjected,  will  be  best  described  under  these  respective  heads,  since 
these  litiuors  arc  themselves  mixtures  of  alcohol  and  water  with  sugar,  coloring  matters, 
flavoring  ethers,  &c. 

ALDEHYDE.  By  this  word  is  understood  the  fluid  obtained  from  alcohol  by  the 
removal  of  two  equivalents  of  hvdrogen.  Thus,  alcohol  being  represented  by  the  formula 
t:^  H'^  O",  aldehyde  becomes  C  H*  0^ 


ALDER.  39 

Preparation. — Aldehyde  is  prepared  by  various  processes  of  oxidation.  Liebig  has 
published  several  methods,  of  which  the  following  is  perhaps  the  best :  Three  parts  of 
peroxide  of  manganese,  three  of  sulphuric  acid,  two  of  water,  and  two  of  alcohol  of  80  per 
cent.,  are  well  mixed  and  carefully  distilled  in  a  spacious  retort.  The  extreme  volatility  of 
aldehyde  renders  good  condensation  absolutely  necessary.  The  contents  of  the  retort  are 
to  be  distilled  over  a  gentle  and  manageable  fire  until  frothing  commences,  or  the  distillate 
becomes  acid.  This  generally  takes  place  when  about  one-third  has  passed  over.  The  fluid 
in  the  receiver  is  to  have  about  its  own  weight  of  chloride  of  calcium  added,  and,  after 
slight  digestion,  is  to  be  carefully  distilled  on  the  water-bath.  The  distillate  is  again  to  be 
treated  in  the  same  way.  By  these  processes  a  fluid  will  be  obtained  entirely  free  from 
water,  but  containing  several  impurities.  To  obtain  the  aldehyde  in  a  state  of  purity,  it  is 
necessary,  in  the  first  place,  to  obtain  aldehyde-ammonia ;  this  may  be  accomplished  in  the 
foll»wing  manner : — The  last  distillate  is  to  be  mixed  in  a  flask  with  twice  its  volume  of 
ether,  and,  the  flask  being  placed  in  a  vessel  surrounded  by  a  freezing  mixture,  dry  ammo- 
niacal  gas  is  passed  in  until  the  fluid  is  saturated.  In  a  short  time  crystals  of  the  com- 
pounds sought  separate  in  considerable  quantity.  The  aldehyde-ammonia,  being  collected 
on  a  filter,  or  in  the  neck  of  a  funnel,  is  to  be  washed  with  ether,  and  dried  by  pressure 
between  folds  of  filtering  paper,  followed  by  exposure  to  the  air.  It  now  becomes  neces- 
sary to  obtain  the  pure  aldehyde  from  the  compound  with  ammonia.  For  this  purpose  two 
parts  are  to  be  dissolved  in  an  equal  ciuantity  of  water,  and  three  parts  of  sulphuric  acid, 
mixed  with  four  of  water,  are  to  be  added.  The  whole  is  to  be  distilled  on  the  water-bath, 
the  temperature,  at  first,  being  very  low,  and  the  operation  being  s-  )pped  as  soon  as  the 
water  boils.  The  distillate  is  to  be  placed  in  a  retort  connected  with  a  good  condensing 
apparatus,  and,  as  soon  as  all  the  joints  are  known  to  be  tight,  chloride  of  calcium,  in  frag- 
ments, is  to  be  added.  The  heat  arising  from  the  hydration  of  the  chloride  cai»es  the  dis- 
tillation to  commence,  but  it  is  carried  on  by  a  water-bath.  The  distillate,  after  one  more 
rectification  over  chloride  of  calcium,  at  a  temperature  not  exceeding  80^  F.,  will  consist 
of  pure  aldehyde.  Aldehyde  is  a  colorless,  very  volatile,  and  mobile  fluid,  having  the  den- 
sity O^SOO  at  o2\  It  boils,  under  ordinary  atmospheric  pressure,  at  70^  F.  Its  vapor 
density  is  1-532.  Its  formula  corresponds  to  four  volumes  of  vapor;  we  consequently 
obtain  the  theoretical  vapor  density  by  multiplying  its  atomic  weight  =  44  by  half  the 
density  of  hydrogen,  or  .034G.  The  number  thus  found  is  1-5224,  corresponding  as  nearly 
as  could  be  desired  to  the  experimental  residt. 

Aldehyde  is  produced  in  a  great  number  of  processes,  particularly  during  the  dcstructivo 
distillation  of  various  organic  matters,  and  in  processes  of  oxidation.  From  alcohol,  alde- 
hyde may  be  ])rocured  by  oxidation  with  platinum  black,  nitric  acid,  chromic  acid,  chlorine 
(in  presence  of  water),  or,  as  we  have  seen,  a  mixture  of  peroxide  of  manganese  and  sul- 
phuric acid.  Certain  oils,  by  destructive  distillation,  yield  it.  Wood  vinegar  in  the  crude 
state  contains  aldehyde  as  well  as  wood  spirit.  Lactic  acid,  when  in  a  combination  with 
weak  bases,  yields  it  on  destructive  distillation.  Various  animal  and  vegetable  products 
afford  aldehyde  by  distillation  with  oxidizing  agents,  such  as  sulphuric  acid  and  peroxide  of 
manganese,  or  bichromate  of  potash. 

The  word  aldehyde,  like  that  of  alcohol,  is  gradually  becoming  used  in  a  much  more 
extended  sense  than  it  was  formerly.  By  the  term  is  now  understood  any  organic  sub- 
stance which,  by  assimilating  two  equivalents  of  hydrogen,  yields  a  substance  having  the 
properties  of  an  alcohol,  or,  by  taking  up  two  equivalents  of  oxygen,  yields  an  acid.  It  is 
this  latter  property  which  has  induced  certain  chemists  to  say  that  there  is  the  same  relation 
between  an  aldehyde  and  its  acid  as  between  inorganic  acids  ending  in  oiis  and  ic.  Several 
very  interesting  and  important  substances  are  now  known  to  belong  to  the  class  of  alde- 
hydes. The  essential  oils  are,  in  several  instances,  composed  principally  of  bodies  having 
the  properties  of  aldehydes.  Among  the  most  prominent  may  bo  mentioned  the  oils  of 
bitter  almonds,  cumin,  cinnamon,  rue,  &c.  An  exceedingly  important  character  of  the 
aldehydes  is  their  strong  tendency  to  combine  with  the  bisuli)hitcs  of  ammonia,  potash,  and 
soda.  By  availing  ourselves  of  this  property,  it  becomes  easy  to  separate  bodies  of  this 
class  from  complex  mixtures,  and,  consequently,  enable  a  i)roximate  analysis  to  be  made. 
Now  that  the  character  of  the  aldehydes  is  becoming  better  understood,  the  chances  of  arti- 
ficially producing  the  essential  oils  above  alluded  to  in  the  commercial  scale  become  greatly 
increased.  Several  have  already  been  formed,  and,  although  hi  very  small  ([uantities,  the 
success  has  been  sufficient  to  warrant  sanguine  hopes  of  success.  A  sul)stitute  for  one  of 
-them  has  been  for  some  years  known  under  the  very  incorrect  name  of  artificial  oil  of  bitter 
almonds.     Sec  Nituobenzole. — C.  G.  W. 

ALDER.  {Aunc,  Fr.  ;  J'Jrle,  Germ. ;  Alnuii  glutinosa,  Lin.)  A  tree,  different  species 
of  which  are  indigenous  to  Europe,  Asia,  and  America.  The  common  alder  seldom  grows 
to  a  height  of  more  than  40  feet.  The  wood  is  stated  to  be  very  durable  under  water. 
The  piles  at  Venice,  and  those  of  Old  London  Bridge,  are  stated  to  have  been  of  alder ; 
and  it  is  much  used  for  pipes,  pumps,  and  sluices.  The  charcoal  of  this  wood  is  used  for 
gunpowder. 


40 


ALEMBIC. 


ALEMBIC,  a  still  {which  sec).  The  term  is,  however,  applied  to  a  still  of  peculiar  con- 
struction, in  which  the  head.,  or  capital,  is  a  separate  piece, 
fitted  and  ground  to  the  neck  of  the  boiler,  or  cucurbit,  or 
otherwise  carefully  united  with  a  lute.  The  alembic  has  this 
advantage  over  the  common  retort,  that  the  residue  of  distilla- 
tion may  be  easily  cleared  out  of  the  body.  It  is  likewise 
capable,  when  skilfully  managed,  of  distilling  a  much  larger 
cjuantity  of  liquor  in  a  given  time  than  a  retort  of  cfjual  capn- 
city.  In  France  the  term  alembic,  or  rather  alambic.  is  used 
to  designate  a  glass  still. 

ALGAROTH,  POWDER  OF.      Povdcr  of  Afr/arotti,— 

Enrfli'ih  Foii-cler.     This  salt  was  discovei-ed  by  Algarotti,  a 

physician   of  Verona.      Chloride  of  antimony  is  formed  by 

boiling  black  sulphide  of  antimony  with  hydrochloric  acid  :  on 

pouring  the  solution  into  water,  a  white  flocky  precipitate  falls, 

cS^^ESSr^    which  is  an  oxichloridc  of  antimony.     If  the  water  be  hot, 

the  precipitate  is  distinctly  crystalline  ;  this  is  the   powder  of 

algaroth.     This  oxichloride  is  used  to  furnish  oxide  of  antimony  in  the  preparation  of  tartar 

emeiic. 

ALGyE.  {Varcch,  Fr.  ;  Seerjras,  or  Alr/e,  Germ.)  A  tribe  of  subaqueous  plants,  in- 
cluding the  seaweeds  {fucus)  and  the  lavers  (ulva)  growing  in  salt  water,  and  the  fresh 
water  confervas.  We  have  only  to  deal  with  those  seaweeds  which  are  of  any  commercial 
value.  These  belong  to  the  great  division  of  the  jointlcnii  ahicf,  of  which  160  species  are 
known  as  natives  of  the  British  Isles.  In  the  manufacture  of  Kelp,  (see  Kelp,)  all  the  varie- 
ties of  thiatdivision  may  be  used.  The  edible  sorts,  such  as  the  birds'  nests  of  the  Eastern 
Archipelago,  those  which  we  consume  in  this  country,  as  lavers,  carrageen,  or  Irish  moss, 
&c.,  belong  to  the  s:mie  group,  as  do  also  those  which  the  agriculturalists  employ  for  manure. 
Dr.  Pereira  gives  the  Ibllowing  list  of  esculent  seaweeds  : — 


lihodomcnia  pahnata  (or  Dulse). 
lihodoinoiia  cilia/a. 
Laminaria  saccharina. 


Jr/deea  cduU.l. 
A/aria  eseidenta. 
Ulva  latissima. 


nhodomevia  palnutta  passes  imder  a  variety  of  names,  dulse,  dylish,  or  dellish,  and 
amongst  the  Highlanders  it  is  called  dullinrj,  or  waterleaf.  It  is  employed  as  food  by  the 
poor  of  many  nations  ;  when  well  washed,  it  is  chewed  by  the  peasantry  of  Ireland  without 
being  dressed.  It  is  nutritious,  but  sudorific,  has  the  smell  of  violets,  imparts  a  mucila- 
ginous feel  to  the  mouth,  leaving  a  slightly  acrid  taste.  In  Iceland  the  dulse  is  thoroughly 
washed  in  fresh  water  and  dried  in  the  air.  W'hen  thus  treated  it  becomes  covered  with  a 
white  powdery  substance,  which  is  sweet  and  palatable  ;  this  is  viannite,  (see  Manna,)  which 
Dr.  Stenhouse  proposes  to  obtain  from  seaweeds.  "  In  the  dried  state  it  is  used  in  Iceland 
with  fish  and  butter,  or  else,  by  the  higher  classes :  ))oilcd  in  milk  with  the  addition  of  rye 
flour.  It  is  preserved  packed  in  close  casks  ;  a  fermented  liquor  is  produced  in  Kam- 
schatka  from  this  seaweed,  and  in  the  north  of  Europe  and  in  the  Grecian  Archipelago 
cattle  are  fed  upon  it." — Stenhouse. 

Laminaria  saccharina  yields  12'15  per  cent,  of  mannite,  while  the  lihodomcnia  pal- 
viata  contains  not  more  than  2  or  3  per  cent. 

Iridaa  ednlis. — The  fronds  of  this  weed  are  of  a  dull  piu'ple  color,  flat,  and  succulent. 
It  is  employed  as  food  by  fishermen,  either  raw  or  pinched  between  hot  irons,  and  its  taste 
is  then  said  to  resemble  roasted  oysters. 

Alarin  cscn/enta. — Mr.  Drummond  informs  us  that,  on  the  coast  of  Antrim,  "  it  is  often 
gathered  for  eating,  but  the  part  used  is  the  leaflets,  and  not  tlic  midrib,  as  is  commonly 
stated.  These  have  a  very  pleasant  taste  and  flavor,  but  soon  cover  the  mouth  with  a  tena- 
cious greenish  crust,  which  causes  a  sensation  somewhat  like  that  of  the  fat  of  a  heart  or 
kidney." 

Ulva  lati!<s!inri,  (Broad  green  laver.) — This  is  rarely  used,  being  considered  inferior  to 
the  Porphi/ra  laciniata,  (Laciniated  purple  laver.)  This  alga  is  abundant  on  all  our  shores. 
It  is  pickled  with  salt,  and  sold  in  England  as  laver,  in  Ireland  as  sloke,  and  in  Scotland  as 
F.lnak.  The  London  shops  are  mostly  supplied  with  laver  from  the  coasts  of  Devonshire. 
AVhen  stewed,  it  is  brought  to  the  table  and  eaten  with  pepper,  butter  or  oil,  and  lemon- 
juice  or  vinegar.  Some  persons  stew  it  with  leeks  and  onions.  The  pepper  dulse,  (Lau- 
rcncia  pinnatifida,)  distinguished  for  its  pungent  taste,  is  often  used  as  a  condiment  when 
other  seaweeds  are  eaten.  "  Tangle,"  {Laminaria  die/ifnta,)  so  called  in  Scotland,  is 
termed  "  red-ware  "  in  the  Ofkneys,  "  sea-wand  "  in  the  Highlands,  and  "  sea-girdlcs  "  in 
England.  The  flat  leathery  fronds  of  this  weed,  when  yoimg,  are  employed  as  food.  Sir. 
Simmonds  tells  us,  "  Tiicre  was  a  time  when  the  cry  of  '  Buy  dulse  and  tangle  '  was  as  com- 
mon in  the  .streets  of  Edinburgh  and  Glasgow,  as  is  that  of  '  water-cresses'  now  in  our  me- 
tropolis."— Society  of  Arts'  Journal. 


ALKALI.  41 

Laminaria  potatorum. — The  large  sea  tangle  is  used  abundantly  by  the  inhabitants  of 
the  Straits  of  Magellan  and  by  the  Fuegians.  Under  the  name  of  "  Bull  Kelp"  it  is  used 
as  food  in  New  Zealand  and  Van  Diemen  s  Laud.  It  is  stated  to  be  exceedingly  nutritive 
and  fattening. 

Chondrus  crisptts^  (chondrus,  from  x<^''5pos,  cartilage.) — Carrageen,  Irish,  or  pearl  moss. 
For  purposes  of  diet  and  for  medicinal  uses,  this  alga  is  collected  on  the  west  coast  of  Ire- 
land, washed,  bleached  by  exposure  to  the  sun,  and  dried.  It  is  not  unfrequently  used  in 
Ireland  by  painters  and  plasterers  as  a  substitute  for  size.  It  has  also  been  successfully 
applied,  instead  of  isinglass,  in  making  of  blanc-mange  and  jellies ;  and  in  addition  to  its 
use  in  medicine,  for  which  purpose  it  was  introduced  by  Dr.  Todhunter,  of  Dublin,  about 
1831,  a  thick  mucilage  of  carrageen,  scented  with  some  prepared  spirit,  is  sold  as  bando- 
line, fixature,  or  dyxphitique,  and  it  is  employed  for  stiifening  silks.  According  to  Dr. 
Davy,  cai-rageen  consists  of 

Gummy  matter,       ......       28'5 

Gelatinous  matter,         .  .  .  .  .  49*0 

Insoluble  matter,     .  .  .  .  .  .       22'5 

100-0 

Plocaria  Candida. — Ceylon  moss  ;  edible  moss.  This  moss  is  exported  from  the  islands 
of  the  Indian  Archipelago,  forming  a  portion  of  the  cargoes  of  nearly  all  the  junks.  It  is 
stated  by  Mr.  Crawford,  in  his  "  History  of  the  Indian  Archipelago,"  that  on  the  spots  where 
it  is  collected,  the  prices  seldom  exceed  from  5s.  8d.  to  7s.  6d.  per  cwt.  The  Chinese  use 
it  in  the  form  of  a  jelly  with  sugar,  as  a  sweetmeat,  and  apply  it  in  the  arts  as  an  excel- 
lent paste.  The  gummy  matter  which  they  employ  for  covering  lanterns,  varnishing  paper, 
&c.,  is  made  chiefly  from  this  moss. 

This  moss,  as  ordinarily  sold,  appears  to  consist  of  several  varieties  of  marine  produc- 
tions, with  the  Plocaria  intermixed. 

The  Agar- Agar  of  Malacca  belongs  to  this  variety ;  and  probably  seaweeds  of  this 
character  are  used  by  the  Salangana  or  esculent  swallow  in  constructing  their  nests,  which 
are  esteemed  so  great  a  delicacy  by  the  Ciiinese.  The  plant  is  found  on  the  rocks  of  Pulo 
Ticoos  and  on  the  shores  of  the  neighboring  islands.  It  is  blanched  in  the  sun  for  two 
days,  or  until  it  is  quite  white.  It  is  obtained  on  submerged  banks  in  the  neighborhood  of 
Macassar,  Celebes,  by  the  Bajow-laut,  or  sea-gipsies,  who  send  it  to  China.  It  is  also  col- 
lected on  the  reefs  and  rocky  submerged  ledges  in  the  neighborhood  of  Singapore.  Mr. 
Montgomery  Martin  informs  us  that  this  weed  is  the  chief  staple  of  Singapore,  and  that  it 
produces  in  China  from  six  to  eight  dollars  per  pccul  in  its  dry  and  bulky  state.  The  har- 
vest of  this  seaweed  is  from  6,000  to  12,000  peculs  annually,  the  pecul  being  equal  to  100 
catties  of  r333  lbs.  each. 

Similar  to  this,  perhaps  the  same  in  character,  is  the  Agal-Agal,  a  species  of  seaweed. 
It  dissolves  into  a  glutinous  substance.  Its  principal  use  is  for  gumming  silks  and  paper,  as 
nothing  equals  it  for  paste,  and  it  is  not  liable  to  be  eaten  by  insects.  The  Chinese  make  a 
beautiful  kind  of  lantern,  formed  of  netted  thread  washed  over  with  this  gum,  and  which  is 
extremely  light  and  transparent.  It  is  brought  by  coasting  vessels  to  Prince  of  Wales 
Island,  and  calculated  for  the  Chinese  market. —  Oriental  Commerce. 

ALIMENT.  {Alimentum,  from  alo,  to  feed.)  The  food  necessary  for  the  human  body, 
and  capable  of  maintaining  it  in  a  state  of  health. 

1.  Nitrogenous  substances  are  required  to  deposit,  from  the  blood,  the  organized  tissue 
and  solid  muscle ; 

2.  And  carbonaceous,  non-nitro2;enous  bodies,  to  aid  in  the  processes  of  respiration,  and 
iji  the  supply  of  carbonaceous  elements,  as  fat,  &c.,  for  the  due  support  of  animal  heat. 

For  information  on  these  substances,  consult  Liebig's  "  Animal  Chemistry,"  the  investi- 
gations of  Dr.  Lyon  Playfair,  and  Dr.  Robert Dundas Thompson's  "Experimental  Researches 
on  Food,"  1846. 

ALKALI.  A  term  derived  from  the  Arabians,  and  introduced  into  Europe  when  the 
Mahometan  conquerors  pushed  their  conquests  westward.  Al,  el,  or  ul,  as  an  Arabic 
noun,  denotes  "  God,  Heaven,  Divine."  As  an  Arabic  particle,  it  is  prefixed  to  words  to 
give  them  a  more  emphatic  signification,  much  the  same  as  our  particle  the ;  as  in  Alcoran, 
the  Koran  ;  alchymist,  the  chemist. 

Kali  was  the  old  name  for  the  plant  producing  potash,  (the  glasswort,  so  called  from  its 
use  in  the  manufacture  of  glass,)  and  alkali  signified  no  more  than  the  kali  plant.  Potash  and 
soda  were  for  some  time  confounded  together,  and  were  hence  called  alkalis.  Ammonia, 
which  much  resembles  them  when  dissolved  in  water,  was  also  called  an  alkali.  Ammonia 
was  subsefjuently  distinguished  as  the  volatile  alkali,  potash  and  soda  being  fixed  alkalix. 
Ammonia  was  also  called  the  animal  alkali.  Soda  was  the  mineral  alkali,  l)cing  derived 
from  rock  salt,  or  from  the  ocean  ;  and  pot;ish  received  the  name  of  vegetable  alkali,  from 
its  source  being  the  ashes  of  i)lants  growing  upon  the  land.     Alkalis  are  characterized  by 


1 


42 


ALKALIS,  ORGANIC. 


being  very  soluble  in  water,  by  neutralizing  the  strongest  acids,  by  turning  brown  vegetable 
yellows,  and  to  green  the  vegetable  reds  and  blues. 

Some  chemists  classify  all  salifiable  bases  under  this  name. 

In  commercial  language,  the  term  is  applied  to  an  impure  soda,  the  imports  of  which 
were — 

Imports. 


Alkali  and  Barilla. 

1S53. 

1S54. 

1&55. 

1S56. 

Portugal           ..... 

Spain       ...... 

Canary  Islands         .... 

Greece    

Two  Sicilies 

Egypt      ...... 

Peru 

Other  parts 

Total       ...         - 

Cwts. 

2,510 
15,220 

9,240 

7,920 

2,040 
20 

Cwts. 

5,480 
7,840 
3,160 
2,400 
4,800 
1,900 
160 

Cwts. 

1,000 
2,520 

10,640 
500 

Cwts. 

3,560 

3,480 

9,320 

4,760 
80 

36,980 

25,740 

14,660' 

21,200 

Our  Exports  during  the  same  periods  being  as  follows: — 

Alkali  and  Barilla. 

1S53. 

1S54. 

1S55. 

1&5C.        i 

Cwts. 

Cwts. 

Cwts. 

Cwts. 

Russia — Northern  Ports 

13,845 

4,208 

- 

82,667 

"          Southern  Ports 

7,079 

200 

Sweden  

7,804 

13,478 

14,908 

14,924 

Denmark 

39,366 

40,329 

52,721 

39,417 

Prussia 

82,735 

96,839 

104,111 

85,364 

Hanover           ..... 

13,989 

9,715 

18,871 

25,029 

Hanse  Towns           .... 

97,939 

93,774 

77,648 

83,385 

Holland 

112,370 

112,023 

114,068 

121,645 

Belgium 

10,069 

16,837 

21,293 

39,650 

France    ...... 

- 

. 

- 

9,972 

Spain  and  the  Canaries    - 

- 

0,921 

4,090 

11,042 

Sardinia            

- 

. 

- 

7,326 

Austrian  Territories         ... 

28,957 

21,023 

22,587 

27,124 

Turkey    

. 

. 

13,010 

9,142 

Australia          ..... 

49,377 

52,890 

19,882 

37,790 

British  North  America    - 

12,271 

14,344 

16,102 

25,520 

United  States           .... 

550,735 

559,942 

494,254 

723,089 

Brazil      ...-.- 

12,281 

20,153 

23,805 

26,149 

Chili 

. 

10,392 

5,185 

Other  Countries       .... 
Total       .... 

29,771 

33,747 

42,469 

39,666 

1,070,624 

1,100,315 

1,045,004 

1,405,901 

ALKALIS,  ORGANIC.  During  the  last  few  years  the  number  of  organic  alkaloids  has 
so  greatly  increased,  that  a  considerable  volume  might  be  devoted  to  their  history.  There 
are,  however,  only  a  few  which  have  become  articles  of  commerce.  The  modes  of  prepa- 
ration will  be  given  under  the  heads  of  the  alkalis  themselves.  The  principal  sources  from 
whence  they  are  obtained  are  the  following : — 1.  The  animal  kingdom.  2.  The  vegetable 
kingdom.  3.  Destructive  distillation.  4.  The  action  of  potash  on  the  cyanic  and  cyanuric 
ethers.  5.  The  action  of  ammonia  on  the  iodides,  &c.,  of  the  alcohol  radicals.  6.  The 
action  of  reducing  agents  on  nitro-compounds.  The  principal  bases  existing  in  the  animal 
kingdom  are  creatine  and  sarcosine.  The  vegetable  kingdom  is  much  richer  in  them,  and 
yields  a  great  number  of  organic  alkalis,  of  which  several  are  of  extreme  value  in  medi- 
cine. Modem  chemists  regard  all  organic  alkalis  as  derived  from  the  types  ammonia  or 
oxide  of  ammonium.  Their  study  has  led  to  results  of  the  most  startling  character.  It  has 
been  found  that  not  only  may  the  hydrogen  in  ammonia  and  oxide  of  ammonium  be 
replaced  by  metals  and  compound  radicals  without  destruction  of  the  alkaline  character,  but 
even  the  nitrogen  may  be  replaced  by  phosphorus  or  arsenic,  and  yet  the  resulting  com- 
pounds remain  powerfully  basic.     In  studying  the  organic  bases,  chemists  have  constantly 


ALKALIMETEY. 


43 


had  in  view  the  artificial  production  of  the  bases  of  cinchona  bark.  It  is  true  that  this 
result  has  not  as  yet  been  attained  ;  but,  on  the  other  hand,  bodies  have  been  formed  bav- 
in"' so  many  analogies,  both  in  constitution  and  properties,  with  the  substances  sought,  that 
it  cannot  be  doubted  the  question  is  merely  one  of  time.  The  part  performed  by  the  bases 
existin"  in  the  juice  of  flesh  has  not  been  ascertained,  and  no  special  remedial  virtues  have 
been  detected  in  them  ;  but  this  is  not  the  case  with  those  found  in  vegetables  ;  it  is,  in 
fact  amon"'  them  that  the  most  potent  of  all  medicines  are  found — such,  for  example,  as 
quinine  and  morphia.  It  is,  moreover,  among  vegetable  allialoids  that  we  find  tlic  sub- 
stances most  inimical  to  life,  for  aconitine,  atropine,  brucine,  coniine,  curarine,  nicotine, 
solanine,  strychnine,  &c.,  &c.,  are  among  their  number.  It  must  not  be  forgotten,  how- 
ever, that,  used  with  proper  precaution,  even  the  most  virulent  are  valuable  medicines. 
The  fearfully  poisonous  nature  of  some  of  the  organic  bases,  together  with  an  idea  that  they 
are  difficult  to  detect,  has  unhappily  led  to  their  use  by  the  poisoner ;  strychnine,  especially, 
has  acquired  a  painful  notoriety,  in  consequence  of  its  employment  by  a  medical  man  to 
destroy  persons  whose  lives  he  had  insured.  Fortunately  for  society,  the  skill  of  the 
analyst  has  more  than  kept  pace  with  that  of  the  poisoner ;  and  without  regarding  the 
extravagant  assertions  made  by  some  chemists  as  to  the  minute  quantities  of  vegetable 
poisons  they  are  able  to  detect,  it  may  safely  be  asserted  that  it  would  be  very  difficult  to 
administer  a  fatal  dose  of  any  ordinary  vegetable  poison  without  its  being  discovered. 
Another  check  upon  the  poisoner  is  found  in  the  fact  that  those  most  difficult  of  isolation 
from  complex  mixtures  are  those  which  cause  such  distinct  symptoms  of  poisoning  in  the 
victim,  that  the  medical  attendant,  if  moderately  observant,  can  scarcely  fail  to  have  his 
suspicions  aroused. 

Under  the  heads  of  the  various  alkaloids  will  be  found  (where  deemed  of  sufficient 
importance)  not  merely  the  mode  of  preparation,  but  also  the  easiest  method  of  detection. 
— C.  G.  W. 

ALKALIMETER.  There  are  various  kinds  of  alkalimetcrs,  but  it  will  be  more  conven- 
ient to  expUiin  tlieir  construction  and  use  in  the  article  on  Alkalimetry,  to  which  the 
reader  is  referred. 

ALKALIMETRY.  1.  The  object  of  alkalimetry  is  to  determine  the  quantity  of  caustic 
alkali  or  of  carbonate  of  alkali  contained  in  the  potash  or  soda  of  commerce.  The  prin- 
ciple of  the  method  is,  as  in  acidimetry,  based  upon  Dalton's  law  of  chemical  combining 
ratios — that  is,  on  the  fiict  that  in  order  to  produce  a  complete  reaction,  a  certain  definite 
weight  of  reagent  is  required,  or,  in  other  words,  in  order  to  saturate  or  completely  neu- 
tralize, for  example,  one  equivalent  of  a  base,  exactly  one  equivalent  of  acid  must  be  em- 
ployed, and  vice  versd.  This  having  been  thoroughly  explained  in  the  article  on  Acidim- 
ETUT,  the  reader  is  referred  thereto. 

2.  The  composition  of  the  potash  and  of  the  soda  met  with  in  commerce  presents  very 
great  variations ;  and  the  value  of  these  substances  being,  of  course,  in  propor- 
tion to  the  quantity  of  real  alkali  which  they  contain,  an  easy  and  rapid  method 
of  determining  that  quantity  is  obviously  of  the  greatest  importance  both  to  the 
manufacturer  and  to  the  buyer.  The  process  by  which  this  object  is  attained, 
though  originally  contrived  exclusively  for  the  determination  of  the  intrinsic 
value  of  these  two  alkalis,  (whence  its  name.  Alkalimetry,)  has  since  been  ex- 
tended to  that  of  ammonia  and  of  earthy  bases  and  their  carbonates,  as  will  be 
shown  presently. 

3.  Before,  however,  entering  into  a  description  of  the  process  itself,  we  will 
give  that  of  the  instrument  employed  in  this  method  of  analysis,  which  instru- 
ment is  called  an  alkalimetcr. 

4.  The  common  alkalimeter  is  a  tube  closed  at  one  end,  (see  figure  in  mar- 
gin,) of  about  f  of  an  inch  internal  diameter,  about  9V  inches  long,  and  is 
thus  capable  of  containing  1,000  grains  of  pure  distilled  water.  The  space 
occupied  by  the  water  is  divided  accurately  into  100  divisions,  numbering  from 
above  downwards,  each  of  which,  therefore,  represents  10  grains  of  distilled 
water. 

5.  When  this  alkalimeter  is  used,  the  operator  must  carefully  pour  the  acid 
from  it  by  closing  the  tube  with  his  thumb,  so  as  to  allow  the  acid  to  trickle  in 
drops  as  occasion  may  require  ;  and  it  is  well  also  to  smear  the  edge  of  the  tube 
with  tallow,  in  order  to  prevent  any  portion  of  the  test  acid  I'rom  being  wasted 
by  running  over  the  outside  after  pouring,  which  accident  would,  of  course, 
render  the  analysis  altogether  inaccurate  and  worthless  ;  and,  for  the  same  rea- 
son, after  having  once  begun  to  pour  the  acid  from  the  alkalimeter  by  allowing 
it  to  trickle  between  the  thumb  and  the  edge  of  the  tube,  as  above  mentioned, 
the  thumb  must  not  be  removcHl  from  the  tul)e  till  the  end  of  the  experiment, 
for  otherwise  the  portion  of  acid  which  adheres  to  it  would,  of  course,  be  wasted 
and  vitiate  the  result.  This  uncomfortable  precaution  is  obviated  in  the  other  forms  of 
alkalimeter  now  to  be  described. 


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44 


iU^KALIMETRY. 


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6.  That  represented  in  y?(7.  12  is  Gay-Lussac's  alkalimeter ;  it  is  a  glass  tube  about  14 
inches  high,  and  ^  an  inch  in  diameter,  capable  of  holding  more  than  1,000  grains  of  dis- 
tilled water ;  it  is  accurately  graduated  from  the  top  down- 
wards into  100  divisions,  in  such  a  way  that  each  division 
may  contain  exactly  10  grains  of  water.  It  has  a  small  tube, 
b,  communicating  with  a  larger  one,  which  small  tube  is  bent 
and  bevelled  at  the  top,  c.  This  very  ingenious  instrument, 
known  also  under  the  name  of  "  burette'''  and  " pourct,''  was 
contrived  by  Gay-Lussac,  and  is  by  far  more  convenient  than 
the  common  alkalimeter,  as  by  it  the  test  acid  can  be  unerringly 
poured,  drop  by  drop,  as  wanted.  The  only  drawback  is  the' 
fragility  of  the  small  side-tube,  b,  on  which  account  the  com- 
mon alkalimeter,  represented  in  Jig.  11  is  now  generally  used, 
especially  by  workmen,  because,  as  it  has  no  side-tube,  it  is 
less  liable  to  be  broken  ;  but  it  gives  less  accurate  results,  a 
portion  of  the  acid  being  wasted  in  various  ways,  and  it  is, 
besides,  less  manageable.  Gay-Lussac's  "  burette  "  is  there- 
fore preferable ;  and  if  melted  wax  be  run  between  the  space 
of  the  large  and  of  the  small  tube,  the  instrument  is  rendered 
much  less  liable  to  injury  ;  it  is  generally  sold  with  a  separate 
wooden  foot  or  socket,  in  which  it  may  stand  vertically. 

7.  The  following  form  of  alkalimeter,  {fg.  13,)  which  I 
contrived  several  years  ago,  will,  I  think,  be  found  equally 
delicate  but  more  convenient  still  than  that  of  Gay-Lussac.  It 
consists  of  a  glass  tube,  a,  of  the  same  dimensions,  and  grad- 
uated in  the  same  manner  as  that  of  Gay-Lussac ;  but  it  is 
provided  with  a  glass  foot,  and  the  upper  part,  b,  is  shaped 
like  the  neck  of  an  ordinary  glass  bottle  ;  c  is  a  bulb  blown  from  a  glass  tube,  one  end  of 
which  is  ground  to  fit  the  neck,  b,  of  the  alkalimeter,  like  an  ordinary  glass  stopper.  This 
bulb  is  drawn  to  a  capillary  point  at  d,  and  has  a  somewhat  large  opening  at  e.  With  this 
instrument  the  acid  is  perfectly  under  the  control  of  the  operator,  for  the  globular  joint  at 
the  top  enables  him  to  see  the  liquor  before  it  actually  begins  to  drop  out,  and  he  can  then 
regulate  the  pouring  to  the  greatest  nicety,  whilst  its  more  substantial  form  renders  it  much 
less  liable  to  accidents  than  that  of  Gay-Lussac  ;  the  glass  foot  is  extremely  convenient,  and 
is  at  the  same  time  a  great  additional  security.  The  manner  of  using  it  will  be  described 
further  on. 

8.  Another  alkalimeter  of  the  same  form  as  that  which  I  have  just  described,  except  that 
it  is  all  in  one  piece,  and  has  no  globular  enlargement,  is  represented  in  fig.  14.  Its  con- 
struction is  otherwise  the  same,  and  the  results  obtained  are  equally 

delicate  ;  but  it  is  less  under  perfect  control,  and  the  test  acid  is  very 
liable  to  run  down  the  tube  outside :  this  defect  might  be  easily 
remedied  by  drawing  the  tube  into  a  finer  and  more  delicate  point, 
instead  of  in  a  thick,  blunted  projection,  from  which  the  last  drop 
cannot  be  detached,  or  only  with  difficulty,  and  imperfectly.  A  glass 
foot  would,  moreover,  be  an  improvement. 

9.  With  Schuster's  alkalimeter,  (represented  in  ^y.  15,)  the  strength 
of  alkalis  is  determined  by  the  u-eig/it,  not  by  the  measure,  of  the  acid 
employed  to  neutralize  the  alkali ;  it  is,  as  may  be  seen,  a  small  bottle 
of  thin  glass,  having  the  form  of  the  head  of  the  alkalimeter  repre- 
sented mjig.  13.  We  shall  describe  further  on  the  process  of  analysis 
with  this  alkalimeter. 

10.  There  are  several  other  forms  of  alkalimeter,  but  those  which 
have  been  alluded  to  are  almost  exclusively  used, 
and  whichever  of  them  is  employed,  the  process  is 
the  same — namely,  pouring  carefully  an  acid  of  a 
known  strength  into  a  known  weight  of  the  alkali 
under  examination,  until  the  neutralizing  point  is 
obtained,  as  will  be  fully  explained  presently. 

11.  Blue  litmus-paper  being  immediately  red- 
dened by  acids  is  the  reagent  used  for  ascertaining 
the  exact  point  of  the  neutralization  of  the  alkali 
to  be  tested.  It  is  prepared  by  pulverizing  one  part 
of  commercial  litmus,  and  digesting  it  in  six  parts 
of  cold  water,  filtering,  and  dividing  the  blue  liquid 

into  two  equal  portions,  adding  carefully  to  one  of  the  portions,  and  one  drop  at  a  time,  as 
much  very  dilute  sulphuric  acid  as  is  sufficient  to  impart  to  it  a  slight  red  color,  and  pouring 
the  portion  so  treated  into  the  second  portion,  wliich  is  intensely  blue,  and  stirring  the 


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ALKALIMETRY. 


45 


whole  together.  The  mixture  so  obtained  is  neutral,  and  by  immersing  slips  of  white  blot- 
ting-paper into  it,  and  carefully  drying  them  by  hanging  them  on  a  stretched  piece  of 
thread,  an  exceedingly  sensitive  test  paper  of  a  light  blue  color  is  obtained,  which  should  be 
kept  in  a  wide-mouth  glass-stoppered  bottle,  and  sheltered  from  the  air  and  light. 

12.  Since  the  principle  on  which  alkalimetry  is  based  consists  in  determining  the  amount 
of  acid  which  a  known  weight  of  alkali  can  saturate  or  neutralize,  it  is  clear  that  any  acid 
having  this  power  can  be  employed. 

13.  The  test  acid,  however,  generally  preferred  for  the  purpose  is  sulphuric  acid,  because 
the  normal  solution  of  that  acid  is  more  easily  prepared,  is  less  liable  to  change  its  strength 
by  keeping,  and  has  a  stronger  reaction  on  litmus-paper  than  any  other  acid.  It  is  true 
that  other  acids — tartaric  acid,  for  example — can  be  procured  of  greater  purity,  and  that,  as 
it  is  dry  and  not  caustic,  the  quantities  required  can  be  more  comfortably  and  accurately 
weighed  off;  and  on  this  account  some  chemists,  after  Buchner,  recommended  its  use,  but 
the  facility  with  which  its  aqueous  solution  becomes  mouldy  is  so  serious  a  drawback,  that  it 
is  hardly  ever  resorted  to  for  that  object. 

14.  When  sulphuric  acid  is  employed,  the  pure  acid  in  the  maximum  state  of  concen- 
tration, or,  as  it  is  called  by  chemists,  the  pure  hydrate  of  sulphuric  acid,  specific  gravity 
r8485,  is  preferable.  Such  an  acid,  however,  is  never  met  with  in  commerce,  for  the 
ordinary  English  oil  of  vitriol  is  seldom  pure,  and  never  to  the  maximum  state  of  concen- 
tration ;  the  operator,  however,  may  prepare  it  by  distilling  ordinary  oil  of  vitriol,  but  as 
the  specific  caloric  of  the  vapor  of  sulphuric  acid  is  very  small,  the  distillation  is  a  som^ 
what  hazardous  operation,  unless  peculiar  precaution  be  taken.  The  following  apparatus, 
however,  allows  of  the  acid  being  distilled  in  a  perfectly  safe  and  convenient  manner ;  it 
consists  of  a  plain  glass  retort,  charged  with  oil  of  vitriol,  a  little  protosulphate  of  iron  is 
added,  for  the  purpose  of  destroying  any  nitrous  products  which  the  acid  may  evolve,  and 
it  is  then  placed  into  a  cylinder  of  iron,  the  bottom  of  which  is  perforated  with  holes  about 
three-quarters  of  an  inch  in  diameter,  except  in  the  middle,  where  a  large  hole  is  cut  of  a 
suitable  size  for  the  retort  to  rest  upon  ;  the  sides  of  the  cylinder  are  likewise  perforated,  as 
represented  in  fg.  16.  Ignited  charcoal  is  then  placed  all  round  the  retort,  the  bottom  of 
which  protruding,  out  of  the  influence 

of  the  heat,  allows  the  ebullition  to 
proceed  from  the  sides  only.  It  is 
well  to  put  into  the  retort  a  few  frag- 
ments of  quartz  or  a  few  lengths  of 
platinum  wire,  the  effect  of  which  is 
to  render  the  ebullition  more  regular. 

15.  In  order  to  prevent  the  acid 
fumes  from  condensing  in  the  neck 
of  the  retort,  it  should  be  covered 
with  a  cover  of  sheet  iron,  as  repre- 
sented in  fg.  16. 

16.  The  first  fourth  part  which  dis- 
tils over  should  be  rejected,  because 

it  is  too  weak  ;  the  next  two-fourths  are  kept,  and  the  operation  is  then  stopped,  leaving 
the  last  fourth  part  of  the  acid  in  the  retort.  The  neck  of  the  retort  should  be  about  four 
feet  long,  and  about  one  and  a  half  inches  in  the  bore,  and  be  connected  with  a  large  re- 
ceiver ;  and  as  the  necks  of  retorts  are  generally  much  too  short  for  the  purpose,  an  adapter 
tube  should  be  adjusted  to  it  and  to  the  receiver,  but  very  loosely ;  this  precaution  is  ab- 
solutely necessary,  for  otherwise  the  hot  acid  falling  on  the  sid<;s  of  the  receiver  would 
crack  it ;  things,  in  fact,  should  be  so  arranged  that  the  hot  drops  of  the  distilling  acid  may 
fall  into  the  acid  which  has  already  distilled  over.  Do  not  surround  the  receiver  with  cold 
water,  for  the  hot  acid  dropping  on  the  refrigerated  surface  would  also  certainly  crack  it. 
The  acid  so  obtained  is  pure  oil  of  vitriol,  or  monohydrated  sulphuric  acid,  SO',  IIO,  and  it 
should  be  kept  in  a  well-stoppered  and  dry  flask. 

17.  For  commercial  assays,  however,  and,  indeed,  for  every  purpose,  the  ordinary  con- 
centrated sulphuric  acid  answers  very  well  :  when  used  for  the  "determination  of  the  value  of 
potashes,  it  is  made  of  such  a  strength  that  each  division  (or  10  water-grains'  measure)  of 
the  alkalimeter  saturates  exactly  one  grain  of  pure  potash :  an  acid  of  that  particular 
strength  is  prepared  as  follows  : — 

18.  Take  112-70  grains  of  pure  neutral  and  anhydrous  carbonate  of  soda,  and  dissolve 
them  in  about  5  fluid  ounces  of  hot  water.*  This  quantity,  namely,  112-76  grains,  of 
neutral  carbonate  of  soda  will  exactly  saturate  the  same  quantity  of  pure  sulphuric  acid  (SO'') 
that  100  grains  of  pure  potash  would.  It  is  advisable,  however,  to  prepare  at  once  a  larger 
quantity  of  test  solution  of  carbonate  of  soda,  which  is  of  course  easily  done,  as  will  be 
shown  presently. 

*  Anhyilrous,  or  dry,  neutral  carbonate  of  soda  may  bo  obtained  by  keeping  a  certain  qnanlity  of 
pure  bicarbonate  of  soda  for  a  sliort  time,  at  a  dull  red  heat,  in  a  platinum  crucible:  the  bicarbonate  is 
converted  into  its  neutral  carbonate,  of  course  free  from  water. 


46  ALKALIMETEY. 

19.  Mix,  now,  1  part,  by  measure,  of  concentrated  sulphuric  acid  with  10  parts  of 
water,  or  rather — as  it  is  advisable,  where  alkalimetrical  assays  have  frequently  to  be  made, 
to  keep  a  stock  of  test  acid — mix  1,000  water-grains'  measure  of  concentrated  sulphuric 
acid  with  10,000  grains  of  water,  or  any  other  larger  proportions  of  concentrated  sulphuric 
acid  and  water,  in  the  above  respective  proportions ;  stir  the  whole  well,  and  allow  it  to 
cool.  The  mixture  of  the  acid  with  the  water  should  be  made  by  first  putting  a  certain 
([uantity  of  the  water  into  a  glass  beaker  or  matrass  of  a  suitable  size,  then  pouring  the 
concentrated  acid  slowly  therein,  while  a  gyratory  motion  is  imparted  to  the  liquid.  The 
vctiriel  containing  the  acid  is  then  rinsed  with  the  water,  and  both  the  i-insing  and  the  rest 
of  the  water  are  then  added  to  the  whole  mass.  "When  quite  cold,  fill  the  graduated  alka- 
limctcr  with  a  portion  of  it  up  to  the  point  marked  0',  taking  the  under  line  of  the  liquid 
as  the  true  level ;  and,  whilst  stirring  briskly  with  a  glass  rod  the  aqueous  solution  of  tlie 
112.76  grains  of  neutral  carbonate  of  soda  above  alluded  to,  drop  the  test  acid  from  the 
alkalimcter  into  the  vortex  produced  by  stirring,  until,  by  testing  the  alkaline  solution  with 
a  strip  of  reddened  litmus-paper  after  every  addition  of  acid,  it  is  found  that  it  no  longer 
shows  an  alkaline  reaction,  (which  is  known  by  the  slip  of  reddened  litmus-paper  not  being 
rendered  blue,)  but,  on  the  contrary,  indicates  that  a  very  slight  excess  of  acid  is  present, 
(which  is  known  by  testing  with  a  slip  of  blue  htmus-paper,  which  will  then  turn  slightly 
red.) 

20.  If,  after  having  exhausted  the  whole  of  the  100  divisions  (1,000  water-grains' 
Pleasure)  of  the  diluted  acid  in  the  alkalimcter,  the  neutralization  is  found  to  be  exactly 
attained,  it  is  a  proof  that  the  test  acid  is  right. 

21.  But  suppose,  on  the  contrary,  (and  this  is  a  much  more  probable  case,)  suppose  that 
only  80  divisions  of  the  acid  in  the  alkalimcter  have  been  required  to  neutralize  the  alka- 
line solution,  it  is  then  a  proof  that  the  test  acid  is  too  strong,  and  accordingly  it  must  be 
further  diluted  with  water,  to  bring  it  to  the  standard  strength  ;  and  this  may  at  once  be 
done,  in  the  present  instance,  by  adding  20  measures  of  water  to  every  80  measures  of  the 
acid.  This  is  best  accomplished  by  pouring  the  whole  of  the  acid  into  a  large  glass  cylin- 
der, divided  into  100  equal  parts,  until  it  reaches  the  mark  or  scratch  corresponding  to  80 
measures ;  the  rest  of  the  glass,  up  to  100,  is  then  filled  up  with  water,  so  that  the  same 
quantity  of  real  acid  will  now  be  in  the  100  measures  as  was  contained  before  in  SO 
measures. 

22.  The  acid  adjusted  as  just  mentioned  should  be  labelled  "  Test  Sulphuric  Acid  for 
Fotasfi"  and  kept  in  well-stoppered  bottles,  otherwise  evaporation  taking  place  woidd  ren- 
der the  remaining  bulk  more  concentrated,  consequently  richer  in  acid  than  it  should  be, 
and  it  would  thus,  of  course,  become  valueless  as  a  test  acid  until  readjusted.  Each  degree 
or  division  of  the  alkalimcter  of  such  an  acid  represents  1  grain  of  pure  potash. 

2'i.  The  alkalimetrical  assa^/  of  soda  is  also  made  with  sulphuric  acid,  in  preference  to 
other  acids,  but  it  must  be  so  adjusted  that  100  alkalimetrical  divisions  (1,000  water-grains' 
measure)  of  acid  will  exactly  neutralize  I'ZO'GS  of  pure  anhydrous  carbonate  of  soda,  that 
quantity  containing  100  grains  of  pure  soda. 

24.  Dissolve,  therefore,  171  grains  of  pure  anhydrous  neutral  carbonate  of  soda,  ob- 
tained as  indicated  before,  in  five  or  six  ounces  of  hot  water,  and  prepare  in  the  meantime 
the  test  sulphuric,  acid,  by  mixing  1  part,  by  measure,  of  ordinary  concentrated  sulphuric 
acid,  with  about  9  parts,  Ijy  measure,  of  water,  exactly  as  described  before  ;  stir  the  whole 
thoroughly,  let  the  mixture  stand  until  it  has  become  quite  cold,  then  pour  1,000  water- 
grains'  measure  of  the  dilute  acid  so  prepared  into  an  alkalimcter — that  is  to  say,  fill  that 
instrument  up  to  0°,  taking  the  under  line  as  the  true  level,  and  then,  whilst  stirring  briskly 
the  aqueous  solution  of  the  171  grains  of  carbonate  of  soda  with  a  glass  rod,  pour  the  acid, 
with  increased  precaution  as  the  saturating  point  is  approaching,  into  the  vortex  produced, 
until  by  testing  the  liquor  alternately  with  reddened  and  with  blue  litmus-paper,  or  with 
gray  litmus-paper,  as  before  mentioned,  the  exactly  neutralized  point  is  hit. 

2.5.  If  the  whole  of  the  100  alkalimetrical  divisions  (1,000  water-grains'  measure)  have 
been  required  to  effect  the  neutralization,  it  is  a  proof  that  the  acid  is  of  the  right  strength ; 
but  if  this  be  not  the  case,  it  must  be  adjusted  as  described  before — that  is  to  say  : — 

26.  Suppose,  for  example,  that  only  75  alkalimetrical  divisions  or  measures  of  the  acid 
in  the  alkalimcter  have  been  required  to  neutralize  the  171  grains  of  neutral  carbonate  of 
soda  operated  upon,  then  75  measures  of  tlie  acid  should  be  poured  at  once  into  a  glass 
cvlinder  accurately  divided  into  100  parts ;  the  remaining  25  divisions  should  then  \)C  filled 
with  Avater,  and  tlie  whole  being  now  stirred  up,  100  parts  of  the  liquor  will  of  course  con- 
tain as  much  real  acid  as  75  parts  contained  before,  and  accordingly  the  acid  may  now  be 
used  as  a  test  acid  for  the  alkalimetrical  assay  of  soda,  each  degree  or  division  of  the  alka- 
limcter representing  one  grain  of  pure  soda. 

27.  The  stock  of  test  acid  should  be  kept  in  well-stoppered  flasks,  that  it  may  not  vary 
in  strength  by  cvapoi-ation,  and  be  labelled  "  Test  Sulphuric  Acid  for  >SWrt." 

28.  Instead,  however,  of  keeping  two  kinds  of  "  test  sulphuric  acid,"  of  different  satu- 
r.iting  powers  as  described,  the  one  for  potash,  the  other  for  soda,  one  kind  only  may  be 


ALKALIMETRY. 


47 


prepared  so  as  to  serve  for  both  alkalis,  by  constructing,  as  is  very  often  done,  an  alkalime- 
ter  adjusted  so  as  to  indicate  the  quantities  of  the  acid  of  a  given  strength  required  for  the 
saturation  or  neutralization  of  both  potasli  or  soda,  or  of  their  respective  carbonates ;  and 
this,  in  fact,  is  the  alkalimeter  most  in  use  in  the  factory. 

It  should  be  in  sliape  similar  to  that  of  Gay-Lussac's,  (see  ///.  12,)  or  that  described  in 
figs.  13  and  14  ;  but,  like  that  represented  by  fig.  11,  it  generally  consists  of  a  tube  closed 
at  one  end,  about  three-fourths  of  an  inch  internal  diameter  and  about  9^  inches  in  length  ;' 
it  is  graduated  into  loO  equal  parts,  and  every  division  is  numbered  from  above  downwards 

(see  A>  l'^)- 

The  following  directions  for  their  construction  are  given  by  Professor  Faraday  :  "  Let 
the  tube  represented  in  the  margin  have  100'  grains  of  water  weighed  into 
it ;  then  let  the  space  it  occupies  be  graduated  into  100  equal  parts,  and  yj 

every  ten  divisions  numbered  from  above  downwards.  At  22-1  parts,  or 
77-99  parts  from  the  bottom,  make  an  extra  line,  a  little  on  one  side  or  even 
on  the  opposite  side  of  the  graduation,  and  write  at  it  with  a  scratching  dia- 
mond, soda ;  lower  down,  at  48-G2  parts,  make  another  line,  and  write 
potash;  still  lower,  at  54"43  parts,  a  third  line  marked  carb.  soda;  and  at 
65  part,  a  fourth,  marked  carb.  potash.  It  will  be  observed  that  portions 
are  measured  off  beneath  these  marks  in  the  inverse  order  of  the  equivalent 
number  of  these  substances,  and  consequently  directly  proportionate  to  the 
quantities  of  any  particular  acid  which  will  neutralize  equal  weights  of  the 
alkalis  and  their  carbonates.  As  these  points  are  of  great  importance,  it 
will  be  proper  to  verify  them  by  weighing  into  the  tubes  first  350,  then 
513-8,  and  lastly  779'9  grains  of  water,  which  will  correspond  with  the  marks 
if  they  are  correct,  or  the  graduation  may  be  laid  down  from  the  surface  of 
the  four  portions  of  fluid  when  weighed  in,  without  reference  to  where  they 
fall  upon  the  general  scale.  The  tube  is  now  completed,  except  that  it 
should  be  observed  whether  the  aperture  can  be  perfectly  and  securely  cov- 
ered by  the  thumb  of  the  left  hand,  and  if  not ;  or,  if  there  be  reason  to  think  cai 
it  not  ultimately  secure,  then  it  should  be  heated  and  contracted  until  suffi- 
ciently small." 

29.  The  test  acid  for  this  alkalimeter  should  have  a  specific  gravity  of  '' 
1.1268  ;  and  such  an  acid  may  be  prepared  by  mixing  one  part,  by  weight, 
of  sulphuric  acid,  specific  gravity  1-82,  with  four  parts  of  water,  and  allow- 
ing the  mixture  to  cool.  In  the  meantime,  100  grains  of  pure  anhydrous 
carbonate  of  soda,  obtained  as  indicated  before,  should  be  dissolved  in  water, 
and  the  test  sulphuric  acid,  of  specific  gravity  1-1268,  prepared  as  abovesaid, 
having  become  quite  cool,  is  poured  into  the  alkalimeter  up  to  the  point 
marked  carbonate  of  soda,  the  remaining  divisions  are  filled  up  with  w'atcr, 
and  the  whole  should  be  well  mixed  by  shaking. 

30.  If  the  whole  of  the  sulphuric  acid,  adjusted  as  was  said,  being  poured  carefully 
into  the  solution  of  the  100  grains  of  the  neutral  carbonate  of  soda,  neutralize  them 
exactly — which  is  ascertained,  as  usual,  by  testing  the  solution  with  litmus-paper,  which 
should  not  be  either  reddened  or  rendered  bluer  by  it — it  is  of  course  a  sign  that  the  test 
is  as  it  should  be — that  is  to  say,  is  of  the  proper  strength ;  in  the  contrary  case,  it  must  be 
finally  adjusted  in  the  manner  already  indicated,  and  which  need  not  be  repeated.  See 
§§  20,  21. 

31.  The  best  and  most  convenient  process  for  the  analyst,  however,  consists  in  prepar- 
ing a  test  acid  of  such  a  strength  that  it  may  serve  not  only  for  all  alkalis,  but  indeed  for 
every  base  ;  that  is  to  say,  by  adjusting  the  test  acid  so  that  100  alkalimetrical  divisions  of 
it  (1,000  water-grains'  measure)  may  exactly  saturate  or  neutralize  one  equivalent  of  every 
base.  This  method,  which  was  first  proposed  by  Dr.  Ure,  is  exceedingly  convenient,  and 
the  possession  of  two  reciprocal  test  liquids,  namely  the  ammonia  test  liquor  of  a  standard 
strength,  of  which  we  gave  a  description  hi  the  article  on  Acidimetry,  and  the  standard  test 
acid  of  which  we  are  now  speaking,  affords,  as  Dr.  Ure  observes,  ready  and  rigid  means  of 
verification.  For  microscopic  analysis  of  alkaline  and  of  acid  matter,  a  graduated  tube  of 
a  small  bore,  mounted  in  a'frame,  with  a  valve  apparatus  at  top,  so  as  to  let  fall  drops  of 
any  size  and  at  any  interval,  is  desirable ;  and  such  an  instrument  Dr.  Ure  employed  for 
many  years ;  but  instead  of  a  tube  with  a  valve  apparatus  at  top,  the  operator  may  uso  a 
graduated  tube  of  a  small  bore,  terminated  by  a  small  length  of  vulcanized  india-ruhher 
tube  pinched  in  a  clamp,  which  may  be  relaxed  in  such  a  way  as  to  permit  also  the  escape 
of  drops  of  any  size  at  any  interval  of  time,  the  little  apparatus  being  under  perfect 
command. 

32.  The  test  sulphuric  acid,  of  such  a  strength  that  100  alkalimetrical  divisions  of  it 
can  saturate  one  equivalent  of  every  base,  should  have  a  specific  gravity  of  r032,  and  is 
prepared  as  follows  : — 

Take  53  grains  (one  equivalent)  of  pure  anhydrous  neutral  carbonate  of  soda,  obtained 


^85 

^90 


48  ALKALIMETRY. 

in  the  manner  indicated  before,  (see  §  18,)  and  dissolve  them  in  about  one  fluid  ounce  of 
water.  Prepare,  in  the  meantime,  the  test  sulphuric  acid  by  mixing  one  part,  by  measure, 
of  concentrated  sulphuric  acid  with  about  11  or  12  parts  of  water,  and  stir  tlie  whole  well. 
The  mixture  having  become  quite  cold,  fill  the  alkalimeter  witli  the  cold  diluted  acid  up  to 
the  point  marked  0",  taking  the  under  line  of  the  liquid  as  the  true  level,  and,  whilst  stir- 
ring briskly  the  aqueous  solution  of  the  53  grains  of  carbonate  of  soda  above  alluded  to, 
•pour  the  acid  carefully  from  the  alkalimeter  into  the  vortex  produced  by  stirring,  until,  by 
testing  the  liquor  alternately  with  reddened  and  with  blue  litmus-paper,  or,  more  conve- 
niently still,  with  gray  litmus-paper,  the  neutralizing  point  is  exactly  hit. 

33.  If  the  whole  of  the  100  divisions  of  the  alkalimeter  had  been  required  to  neutralize 
exactly  the  53  grains  of  pure  anhydrous  carbonate  of  soda,  it  would  be  a  proof  that  the 
acid  is  of  the  right  strength  ;  but  if  this  is  not  the  case,  it  must  be  adjusted  in  the  manner 
described  before,  that  is  to  say : — 

34.  Let  us  suppose,  for  example,  that  only  50  measures  in  the  alkalimeter  have  been 
required  to  saturate  or  neutralize  the  53  grains  of  carbonate  of  soda,  then  50  measures 
should  be  poured  at  once  into  a  glass  cylinder  accurately  divided  into  100  parts,  the  remain- 
ing 50  divisions  should  be  filled  up  with  water,  and  the  whole  being  well  stirred,  100  parts 
of  the  acid  liquor  will  now  contain  as  much,  real  acid  as  was  contained  before  in  the  50 
parts. 

35.  The  acid  may  now  be  labelled  simply,  ^^  Test  or  Normal  Sulphuric  A  cidy  Each 
one  hundred  alkalimetrical  divisions,  or  1,000  water-grains'  measure  of  it,  contain  one 
equivalent,  or  40  grains  of  real  sulphuric  acid  ;  and,  consequently,  each  100  alkalimetrical 
divisions  of  it  will  neutralize  one  equivalent,  or  31  grains  of  soda,  47  of  potash,  17  of 
ammonia,  28  of  lime,  and  so  forth,  with  respect  to  any  other  base. 

36.  The  stock  of  test  or  normal  sulphuric  acid  should,  as  usual,  be  kept  in  well-stop- 
pered bottles,  in  order  to  prevent  concentration  by  evaporation.  By  keeping  in  the  flask 
containing  it  a  glass  bead,  exactly  adjusted  to  the  specific  gravity  of  1 -032,  the  operator 
may  always  ascertain,  at  a  glance,  whether  the  acid  requires  readjusting. 

37.  With  a  Schiister's  alkalimeter,  it  is  convenient  to  prepare  the  test  acid  of  sucli  a 
strength  that,  according  as  it  has  been  adjusted  for  potash  or  for  soda,  10  grains  of  it  will 
exactly  saturate  one  grain  of  one  or  the  other  of  these  bases  in  a  pure  state.  It  is  consid- 
ered that  the  alkalimeter  may  be  charged  with  a  known  weight  of  any  of  the  other  sul- 
phuric test  acids  of  a  known  strength.  Suppose,  for  example,  that  tlie  test  sulphuric  acid 
taken  tiave  a  specific  gravity  of  r032,  we  know,  as  we  have  just  shown,  that  r032  grains' 

weight  of  that  acid  contains  exactly  one  equivalent  of  pure  sul- 
18  phuric  acid  ^  40,  and   is  capable,  therefore,  of  neutralizing  one 

equivalent  of  any  base ;  and,  consequently,  by  taking  a  certain 
weight  of  this  acid  before  beginning  the  assay,  and  weighing  what 
is  left  of  it  after  the  assay,  it  is  very  easy  to  calculate,  from  the 
quantity  of  acid  consumed  in  the  experiment,  what  quantity  of  base 
has  been  neutralized.  Thus  a  loss  of  21-96  —  GO-70  —  33-29 
grains'  weight  of  this  test  acid  represents  one  grain  of  potash,  of 
ammonia,  of  soda  respectively,  and  so  on  with  the  other  bases. 

38.  The  operator  being  thus  provided  with  an  appropriate  test 
acid,  we  shall  now  describe  how  he  should  proceed  with  each  of 
them  in  making  an  alkalimetrical  assay  with  potash. 

In  order  to  obtain  a  reliable  result,  a  fair  average  sample  must 
be  operated  upon.  To  secure  this  the  sample  should  be  taken  from 
various  parts  of  the  mass,  and  at  once  put  in  a  wide-mouth  bottle, 
and  well  corked  up  until  wanted  ;  when  the  assay  has  to  be  made, 
the  contents  of  the  bottle  must  be  reduced  to  powder,  so  as  to 
obtain  a  fair  mixture  of  the  whole  ;  of  this  weigh  out  1,000  grains 
exactly — or  less,  if  that  quantity  cannot  be  spared — and  dissolve 
them  in  a  porcelain  capsule  in  about  8  fluid  ounces  of  distilled  hot 
water,  or  in  that  proportion  ;  and  if  there  be  left  any  thing  like  an  insoluble  residue,  filter, 
in  order  to  sepanite  it,  and  wash  it  on  the  filter  with  small  quantities  of  distilled  water,  and 
pour  the  whole  solution,  with  the  washings  and  rinsings,  into  a  measure  divided  into  10,000 
water-grains'  measure.  If  the  water  used  for  washing  the  insoluble  residue  on  the  filter 
has  increased  the  bulk  of  the  solution  beyond  10,000  water-grains'  measure,  it  must  be 
reduced  by  evaporation  to  that  quantity ;  if,  on  the  contrary,  the  solution  poured  in  the 
measure  stands  below  the  mark  10,000  water-gFains'  measure,  then  as  much  water  must  be 
added  thereto  as  will  bring  the  whole  mass  exactly  to  that  point.  In  order  to  do  this  cor- 
rectly, the  cylindrical  measure  should  stand  well  on  a  table,  and  the  under  or  lower  line 
formed  by  the  liquid,  as  it  reaches  the  scratch  10,000,  is  taken  as  the  true  level. 

39.  This  being  done,  1,000  grains'  measure  of  the  filtrate,  that  is  to  say,  onc-lonth  part 
of  the  whole  solution,  is  transferred  to  a  glass  beaker,  in  which  the  saturation  or  neutraliza- 
tion is  to  be  effected,  which  is  best  done  by  means  of  a  pipette  capable  of  containing 


ALKALIMETRY. 


49 


exactly  that  quantity  when  filled  up  to  the  scratch,  a.  In  order  to  fill  such  a  pipette  it  ia 
sufficient  to  dip  it  into  the  alkaline  solution  and  to  suck  up  the  liquor  a  little  above 
the  scratch,  a ;  the  upper  orifice  should  then  be  stopped  with  the  first  finger,  and  by 
momentarily  lifting  it  up,  the  liquor  is  allowed  slowly  to  fall  from  the  pipette  back 
fto-ain  into  "the  10,000  grains'  measure  until  its  level  reaches  exactly  the  scratch,  a. 
Tlie  last  drop  which  remains  hanging  from  the  point  of  the  pipette  may  be  readily 
detached  by  touching  the  sides  of  the  glass  measure  with  it.  The  1,000  grains  being 
thus  rio-orously  measured  in  the  pipette  should  then  be  transferred  to  the  glass 
l)eaker,°in  whicli  the  neutralization  is  to  take  place,  by  removing  the  finger  alto- 
<'ether,  blowing  into  it  to  detach  the  last  drop,  and  rinsing  it  with  a  little  water. 

40.  Or,  instead  of  the  pipette  just  described,  the  operator  may  measure  1,000 
grains  by  taking  an  alkalimeter  full  of  the  alkaline  solution,  and  emptying  it  into 
the  glass  beaker  in  which  the  neutralization  is  to  take  place,  rinsing  it  with  a  little 
water,  and  of  course  adding  the  rinsing  to  the  mass  in  the  said  glass  beaker. 

41.  Whichever  way  is  adopted,  a  slight  blue  color  should  be  imparled  to  the 
1,000  grains'  measure  of  the  alkaline  solution,  by  pouring  into  it  a  small  quantity 
of  tincture  of  litmus.     The  glass  beaker  should  then  be  placed  upon  a  sheet  of      ]\ 
white  paper,  or  a  slab  of  white  porcelain,  in  order  that  the  change  of  color  produced 

by  the  gradual  addition  of  the  test  acid  may  be  better  observed. 

42.  This  being  done,  if  the  operator  have  decided  upon  using  the  lest  sulphuric,  for 
potash  (§§  17-22),  he  should  take  one  of  the  alkalimeters,  represented  in  fgs.  11,  12,  13, 
or  14,  and  fill  it  up  to  0',  (taking  the  under  line  of  the  liquid  as  the  true  level ;)  then  taking 
the  alkalimeter  thus  charged  in  his  right  hand,  and  in  his  left  the  glass  beaker  containing 
the  alkaline  solution  colored  blue  by  tincture  of  litmus,  he  should  gradually  and  carefully 
pour  the  acid  liquor  into  the  alkaline  solution  in  the  glass  beaker,  to  which  a  circular  motion 
should  be  given  whilst  pouring  the  acid,  or  which  should  be  briskly  stirred,  in  order  to 
insure  the  rapid  and  thorough  mixing  of  the  two  liquors,  and  therefore  their  complete  reac- 
tion ;  moreover,  in  order  at  once  to  detect  any  change  of  color  from  blue  to  red,  the  glass 
beaker  should  be  kept  over  the  white  sheet  of  paper  or  the  white  porcelain  slab,  as  before 
stated. 

43.  At  first  no  effervescence  is  produced,  because  the  carbonic  acid  expelled,  instead  of 
escaping,  combines  with  the  portion  of  the  alkaline  carbonate  as  yet  undecomposed,  which 
it  converts  into  bicarbonate  of  potash,  and  accordingly  no  sensible  change  of  color  is  per- 
ceived ;  but  as  soon  as  a  little  more  than  half  the  quantity  of  the  potash  present  is  satu- 
rated, the  liquor  begins  to  effervesce,  and  the  blue  color  of  the  solution  is  changed  into  one 
of  a  vinous,  that  is,  of  a  purple  or  bluish-red  hue,  which  is  due  to  the  action  of  the  car- 
bonic acid  upon  the  blue  color  of  the  litmus.  More  acid  should  be  still  added,  but  from 
this  moment  with  very  great  care  and  with  increased  caution,  gradually  as  the  point  of  neu- 
tralization is  approached,  which  is  ascertained  by  drawing  the  glass  rod  used  for  stirring  the 
liquor  across  a  slip  of  blue  litmus-paper.  If  the  paper  remains  blue,  or  if  a  red  or  reddish 
streak  is  thereby  produced  which  disappears  on  drying  the  paper  and  leaves  the  latter  blue, 
it  is  a  proof  that  the  neutralization  is  not  yet  complete,  and  that  the  reddish  streak  was  due 
only  to  the  action  of  the  carbonic  acid ;  more  acid  must  accordingly  be  poured  from  the 
alkalimeter,  but  one  drop  only  at  a  time,  stirring  after  each  addition,  until  at  last  the  liquor 
assumes  a  distinct  red  or  pink  color,  which  happens  as  soon  as  it  contains  an  extremely 
slight  excess  of  acid  ;  the  streaks  made  now  upon  the  litmus-paper  will  remain  permanently 
red,  even  after  drying,  and  this  indicates  that  the  reaction  is  complete,  and  that  the  assay  is 
finished. 

44.  If  the  potash  under  examination  were  perfectly  caustic,  the  solution  would  suddenly 
change  from  blue  to  pink,  because  there  would  be  no  evolution  of  carbonic  acid  at  all,  and 
consequently  no  vinous  or  purple  color  produced ;  if,  on  the  other  hand,  the  potash  was 
altogether  in  the  state  of  bicarbonate,  the  first  drops  of  test  acid  would  at  once  decompose 
part  of  it  and  liberate  carbonic  acid,  and  impart  a  vinous  color  to  the  solution  at  the  very 
outset,  which  vinous  color  would  persist  as  long  as  any  portion  of  the  bicarbonate  would 
remain  undecomposed. 

45.  The  neutralizing  point  being  attained,  the  operator  allows  the  sides  of  tlic  alkalim- 
eter to  drain,  and  he  then  reads  off  the  number  of  divisions  which  have  been  employed.  If, 
for  example,  50  divisions  have  been  used,  then  the  potash  examined  contained  50  per  cent, 
of  real  potash.     See  observ.,  §48-49. 

46.  Yet  it  is  advisable  to  repeat  the  assay  a  second  time,  and  to  look  upon  this  first  de- 
termination only  as  an  approximation  which  enables  the  operator,  now  that  he  knows  about 
where  the  point  of  neutralization  lies,  to  arrive,  if  need  be,  by  increased  caution  as  he 
roaches  that  point,  at  a  much  greater  degree  of  precision.  lie  should  accordingly  take 
again  an  alkalimeter  full  (1,000  water-grains'  measure) — that  is  to  say,  another  tenth  part 
of  the  liquor  left  in  the  10,000  grains'  measure — and  add  thereto  at  once  48  or  49  alka- 
limetrical  divisions  of  the  test  acid,  and  after  having  thoroughly  agitated  the  mixture,  pro- 
ceed to  pour  the  acid  carefully,  two  drops  only  at  a  time,  stirring  after  such  addition,  and 

Vol.  III.— 4 


yy^ 


50  ALKALIMETRY. 

touching  a  strip  of  litmus-paper  with  the  end  of  the  glass  rod  used  for  stirring  ;  and  so  he 
should  go  on  adding  two  drops,  stirring,  and  making  a  streak  on  the  litmus-paper,  until  the 
liquor  assumes  suddenly  a  pink  or  onion-red  color,  and  the  streak  made  on  the  litmus-paper 
is  red  also.  The  alkalimeter  is  then  allowed  to  drain  as  before,  and  the  operator  reads  off 
the  number  of  divisions  employed,  from  which  number  two  drops  (or  j-^  of  a  division) 
should  be  deducted  ;  Gay-Lussac  having  shown  that,  in  alkalimetrical  assays,  the  sulphates 
of  alkalis  produced  retard  the  manifestation  of  the  red  color  in  that  proportion.  One  alka- 
limetrical division  generally  consists  of  10  drops,  but  as  this  is  not  always  the  case,  the 
operator  should  determine  for  himself  how  many  drops  are  necessary  to  make  up  one 
division,  and  take  account  of  them  in  the  assay  according  to  the  ratio  thus  found.  In  the 
example  given  before,  and  supposing  10  drops  to  form  one  alkalimetrical  division,  then  tli<j 
percentage  value  of  the  sample  of  potash  under  examination  would  probably  be  as 
follows : — 

Number  of  divisions  of  acid  employed,  .....         50'0 
—  2  drops  acid  in  excess, 02 

Real  percentage  of  potash, 498 

47.  When  the  alkalimeter  described  in  J!r/.  13  is  employed,  the  test  acid  may,  at  the 
beginning  of  the  experiment,  be  poured  from  the  larger  opening,  e  ;  but  towards  the  end — 
that  is,  when  the  neutralizing  point  is  approaching — the  acid  should  be  carefully  poured 
from  the  point,  d,  i7i  single  drops,  or  only  tico  drops  at  a  time,  until  the  saturating  point  is 
hit,  as  we  have  just  said.  If  the  operator  wishes  to  pour  only  one  drop,  he  should  close  the. 
larger  opening,  e,  of  the  bulb  with  the  thumb,  and  then  fill  the  bulb  with  the  test  acid  by 
inclining  the  alkalimeter ;  putting  now  the  alkalimeter  in  an  upright  position,  and  removing 
the  thumb,  a  certain  quantity  of  acid  will  be  retained  in  the  capillary  point,  d  ;  and  if  the 
thumb  be  now  pressed  somewhat  forcibly  against  the  opening,  e,  the  acid  contained  in  the 
capillary  point  will  be  forced  out  and  form  one  drop,  which  will  then  fall  into  the  alkaline 
solution  if  it  be  held  over  it.  If  the  saturation  be  complete,  the  operator,  without  remov- 
ing the  bulb  stopper,  may,  by  applying  his  lips  to  the  large  opening,  e,  suck  the  acid  en. 
gaged  in  the  capillary  point  back  into  the  alkalimeter. 

48.  If  there  should  be  in  the  mind  of  the  operator  any  doubt  as  to  what  is  meant  by  the 
onion-red  color  which  the  liquor  tinged  blue  with  tincture  of  litmus  acquires  when  slightly 
supersaturated,  he  may  pour  into  a  glass  beaker  a  quantity  of  pure  water  equal  to,  or  even 
larger  than,  the  alkaline  solution  operated  upon,  and  tinge  it  blue  with  a  little  tincture  of 
litmus,  to  about  the  same  degree  of  intensity  as  the  alkaline  liquor  under  examination.  If 
he  now  pour  into  the  pure  water  colored  blue  with  litmus,  one  single  drop  of  the  test  acid, 
it  will  acquire  at  once,  by  stirring,  the  onion-red  color  alluded  to,  and  which  he  may  now 
use  as  a  standard  of  comparison. 

49.  Considering  the  rapidity  with  which  these  alkalimetrical  operations  can  be  per- 
formed, the  operator,  unless  he  has  acquired  sufficient  practice,  or  unless  a  great  degree 
of  accuracy  be  not  required,  should  repeat  the  assay  two  or  three  times,  looking  upon  the 
first  determination  only  as  an  approximation,  and  as  a  sort  of  guide  as  to  the  quantity  of 
acid  which  will  be  required  in  the  subsequent  experiments,  whereby  he  will  now  be  enabled 
to  proceed  with  increased  caution  as  he  approaches  the  point  of  saturation ;  but,  at  any 
rate,  if  he  will  not  take  the  little  extra  trouble  of  a  repetition,  he  should,  before  he  begins 
to  pour  the  acid,  take  a  little  of  the  filtered  alkaline  solution  out  of  the  glass  beaker,  as  a 
corps  de  reserve,  which  he  adds  to  the  rest  after  the  saturating  point  has  been  approximated, 
and  from  that  moment  he  may  proceed,  but  with  great  care,  to  complete  the  neutralization 
of  the  whole. 

50.  Do  not  foi^et  that,  as  the  test  sulphuric  acid  must  always  be  added  in  slight  excess 
to  obtain  a  distinct  red  streak  on  the  litmus-paper,  a  correction  is  absolutely  necessary ; 
that  is  to  say,  the  excess  of  sulphuric  acid  employed  must  be  deducted  if  a  strictly  accurate 
result  is  sought. 

51.  If,  instead  of  the  special  alkalimeter  for  potash  above  described,  the  operator  pre- 
fers using  that  prepared  of  such  a  strength  that  100  divisions  of  the  alkalimeter  (100  water- 
grains'  measure)  contain  exactly  one  equivalent  of  each  alkali  or  base,  which  test  sulphuric 
acid,  as  we  have  seen,  has  a  specific  gravity  of  1.032,  (see  §§  31-36,)  he  should  proceed 
exactly  as  indicated  in  §  38,  and  following ;  and  the  alkalimeter  being  filled  with  that  test 
acid,  of  specific  gravity  1.032  up  to  0°,  it  (the  acid)  should  be  poured  carefully  into  the 
aqueous  solution  of  the  alkali  tinged  blue  with  litmus,  until  exact  neutralization  is  attained, 
precisely  in  the  same  manner  as  in  §  38,  and  following. 

52.  The  neutralizing  point  being  hit,  let  us  suppose  that  the  whole  of  the  contents  of 
the  alkalimeter  have  been  employed,  that  the  aqueous  solution  tinged  blue  with  litmus,  is 
not  yet  saturated,  and  that,  after  having  refilled  the  alkalimeter,  the  4  divisions  more  (alto- 
gether 104  divisions)  have  been  required  to  neutralize  the  alkali  in  the  aqueous  solution  ; 
then,  since  100  divisions  (1,000  water-grains'  measure)  of  the  test  acid  now  employed  satu- 


ALKALIMETRY.  51 

rate  exactly  one  equivalent,  that  is,  4Y  of  potash,  the  question  is  now,  What  quantity  of 
potash  will  have  been  saturated  by  the  104  divisions  of  acid  employed?  The  answer  is 
found  by  a  simple  rule  of  proportion,  to  be  nearly  49. 

100  :  47  ::  104  :  x  =  48-88. 

The  sample  of  potash  examined  contained,  therefore,  nearly  49  per  cent,  of  pure  potash. 

53.  If,  instead  of  the  special  test  sulphuric  acid  for  potash,  (§  17,)  or  of  the  test  sul- 
phuric acid  for  potash,  and  other  bases,  (§  28,)  the  operator  uses  the  potash  and  soda  alka- 
limeter,  (§§  31-30,)  the  method  to  be  followed  is  exactly  similar  to  that  described  in  §  42, 
and  following.  Some  of  the  test  sulphuric  acid,  of  specific  gravity  ri208,  is  to  be  poured 
into  the  alkalimetcr  until  it  reaches  the  point  marked  "po^a-sA,"  (that  is  to  say,  48-62 
divisions  of  the  alkalimetcr,)  taking  the  under  line  of  the  liquid  as  the  true  level,  and  the 
remaining  divisions  up  to  0"  are  carefully  filled  with  water.  The  operator  then  closes  the 
aperture  of  the  alkalimetcr  with  the  thumb  of  his  left  hand,  and  the  whole  is  violently 
shaken  so  as  to  obtain  a  perfect  mixture. 

54.  The  acid  so  mixed  must  now  be  carefully  poured  from  the  alkalimetcr  into  the  alka- 
line solution  of  the  potash  under  examination  until  neutralization  is  attained,  precisely  as 
described  in  g  42,  and  following. 

55.  Tlie  neutralizing  point  being  hit,  the  operator  allows  the  sides  of  the  alkalimetcr  to 
drain,  and  he  then  reads  off  the  number  of  divisions  employed  in  the  experiment,  which 
number  indicates  the  percentage  of  real  pota.sh  contained  in  the  sample. 

56.  Had  the  operator  wished  to  estimate  the  quantity  of  potash  as  carbonate  of  potash, 
he  should  have  poured  the  test  acid  into  the  alkalimetcr  up  to  the  point  marked  "  carbonate 
of  potash"  filled  the  remaining  divisions  of  the  alkalimetcr  up  to  0^  with  water,  and  pro- 
ceeding exactly  as  just  mentioned,  the  number  of  divisions  of  acid  employed  would  indi- 
cate the  percentage  of  potash  contained  in  the  sample  as  carbonate  of  potash. 

57.  If  a  Schusicr''s  alkalimetcr  {fff.  15)  be  used,  and  supposing,  for  example,  that  the 
acid  to  be  emplo)-cd  therewith  is  so  adjusted  that  10  grains'  xocicjht  of  it  neutralize  exactly 
1  grain  in  weight  of  potash,  proceed  as  follows: — Take  100  grains  in  weight  of  a  fair 
average  of  the  sample,  previously  reduced  to  powder,  dissolve  them  in  water,  filter  with  the 
precautions  which  have  already  been  described  before,  (§  38,  and  following,)  and  pour  this 
solution  into  a  glass  cylinder  graduated  into  100  parts,  and  capable  of  containing  10,000 
water-grains  ;  fill  it  up  with  water  exactly  as  described  before  ;  of  this  take  now  100  alka- 
limetrical  divisions,  that  "is  to  say,  -,'|f  of  the  whole  solution,  and  pour  it  into  a  glass 
beaker.  On  the  other  hand,  charge  the  Schuster's  alkalimetcr  with  a  certain  quantity  of  the 
test  acid,  and  weigh  it,  along  with  the  alkalimetcr  itself,  in  a  good  balance.  This  done,  pro- 
ceed with  the  neutralization  of  the  solution  in  the  glass  beaker,  by  pouring  the  acid  from 
the  alkalimetcr  in  the  usual  way,  and  with  the  usual  precautions,  until  the  saturation  is 
completed.  Replace  the  alkalimetcr,  with  the  quantity  of  unconsumed  acid,  in  the  scale 
of  the  balance,  weigh  accurately,  and  since  every  grain  of  acid  represents  ^*j  of  a  grain 
of  potash,  the  number  of  grains  of  acid  used  in  the  experiment  indicates  at  once  the  per- 
centage of  real  potash  present  in  the  sample. 

58.  When,  however,  potash  is  mixed  with  soda,  as  is  frequently  the  case  with  the  pot- 
ash of  commerce,  either  accidentally  or  for  fraudulent  purposes,  the  determination  of  the 
amount  of  the  cheaper  alkali  could  not,  until  a  comparatively  recent  period,  be  estimated, 
except  by  the  expensive  and  tedious  process  of  a  regular  chemical  analysis.  In  1844,  how- 
ever, M.  Edmund  Pesier,  Professor  of  Chemistry  at  Valenciennes,  published  an  easy  and 
commercial  method  for  the  estimation  of  the  quantity  of  soda  which  potash  may  contain, 
by  means  of  an  areometer  of  a  peculiar  construction,  to  which  the  name  of  "  Natrometer  " 
has  been  given  by  the  talented  professor. 

59.  The  rationale  of  the  method  is  grounded  upon  the  increase  of  specific  gravity  which 
sulphate  of  soda  produces  in  a  solution  saturated  with  pure  sulphate  of  potash,  and  is  de- 
duced from  the  fact  that  a  solution  saturated  with  neutral  sulphate  of  potash  possesses  a 
uniform  and  constant  density  when  the  saturation  is  made  at  the  same  temperature,  and 
that  the  density  of  such  a  solution  increases  progressively  in  proportion  to  the  quantity  of 
sulphate  of  soda  present ;  an  increase  of  density  so  much  the  more  readily  observable,  that 
the  solubility  of  the  sulphate  of  potash  is  greatly  augmented  by  the  presence  of  sulphate  of 
soda.  It  had  at  first  been  thought  that,  in  order  to  obtain  any  thing  like  accuracy,  it  would 
be  necessary  to  combine  all  the  potash  with  one  same  acid,  preferably  sulphuric  acid ;  and, 
consequently,  that  as  the  potash  of  commerce  always  contains  a  little,  and  sometimes 
a  rather  considerable  quantity,  of  chloride  of  potassium,  the  latter  salt  should  first  be 
decomposed.  Further  experiments,  however,  established  the  fact,  that  in  dissolving  chlo- 
ride of  potassium  in  a  saturated  solution  of  sulphate  of  potash,  the  specific  gravity  of  the 
liquor  is  not  materially  increased,  since  the  introduction  of  as  much  as  50  per  cent,  of 
chloride  of  potassium  does  not  increase  that  density  more  than  3  per  cent,  of  soda  would 
do  when  examined  by  the  natrometer — a  degree  of  accuracy  quite  suflScient  for  commercial 
purposes.     When  soda  is  added  to  a  saturated  solution  of  sulphate  of  potash,  the  further 


52 


ALKALIMETRY. 


21 


addition  of  chloride  of  potassium  thereto  renders  the  specific  gravity  of  the  licpior  less  than 
it  would  have  been  without  that  addition — an  apparent  anomaly  due  to  the  fact  that 
chlorine,  in  presence  of  sulphuric  acid,  of  potash,  and  of  soda,  combines  with  the  latter  bare 
to  form  chloride  of  sodium  ;  and  it  is  this  salt  which  increases  the  solubility  of  suljiliate  of 
potash,  though  in  a  somewhat  less  degree  than  sulphate  of  soda.  Thus,  if  to  a  saturated 
solution  of  sulphate  of  potash  0-14  of  soda  be  added  along  with  0-20  of  chloride  of  potas- 
sium, the  natrometcr  indicates  only  0-125  of  soda.  Seeing,  therefore,  that  in  such  an 
exceptional  case  the  error  does  not  amount  to  more  than  O'OIS  of  error,  it  will  probably  be 
found  unnecessary  in  most  cases  to  decompose  the  chloride  contained  in  the  potashes  of 
commerce,  that  quantity  being  too  small  to  materially  aifect  the  result.  Yet,  as  the  accurate 
determination  of  soda  in  potash  was  a  great  desideratuiin,  M.  Pesicr  contrived  two  processes, 
one  of  which,  in  the  hands  of  the  practised  chemist,  is  as  perfect  as,  but  much  more  rapid 
than,  those  ordinarily  resorted  to ;  the  other,  which  is  a  simpHfication  of  the  first,  yields 
results  of  sufficient  accuracy  for  all  commercial  purposes. 

GO.  First  process. — Take  500  grains  of  a  fair  average  sample  of  the  potash  to  be 
examined,  dissolve  them  in  as  little  water  as  possible,  filter,  and  wash  the  filter  until  the 
washings  are  no  longer  alkaline.  This  filtering,  however,  may  be  dispensed  with  when  the 
potash  is  of  good  quality  and  leaves  but  a  small  residue,  or  when  an  extreme  degree  of 
accuracy  is  not  required.  ■ 

61.  The  potash  being  thus  dissolved,  a  slight  excess  of  sulphuric  acid  is  added  thereto  ; 
the  excess  is  necessary  to  decompose  the  chlorides  and  expel  the  muriatic  acid.  The  liquor 
so  treated  is  then  evaporated  in  a  porcelain  capsule,  about  six  inches  in  diameter ;  and 
when  it  begins  to  thicken  it  should  be  stirred  with  a  glass  rod,  in  order  to  avoid  projections. 
When  dry,  the  fire  must  be  urged  until  the  residue  fuses,  and  it  is  then  kept  in  a  state  of 
tranquil  fusion  for  a  few  minutes.  The  capsule  should  then  be  placed  upon,  and  surrounded 
wit,  hot  sand,  and  allowed  to  cool  down  slowly,  to  prevent  its  cracking,  which  would  happen 
without  this  precaution. 

C2.  The  fused  mass  in  the  capsule  having  become  quite  cold,  should  now  be  treated 
with  as  httle  hot  water  as  possible,  that  is  to  say,  with  less  than  3,000  grains  of  hot  water ; 
and  this  is  best  done  by  treating  it  with  successive  portions  of  fresh 
water.  All  the  liquors  thus  successively  obtained  should  then  be 
poured  into  a  flask  capable  of  holding  about  10,000  grains  of 
water,  and  the  excess  of  sulphuric  acid  7nvst  be  accurately  neutral- 
ized by  a  concentrated  solution  of  pure  carbonate  of  potash — that 
is  to  say,  until  the  color  of  litmus-paper  is  no  longer  affected  by 
the  liquor,  just  as  in  ordinary  alkalimctrical  or  acidimetrical  assays. 
During  this  operation,  a  pretty  considerable  precipitate  of  sulphate 
of  potash  is,  of  course,  produced. 

G3.  The  neutralizing  point  being  exactly  hit,  a  saturated  solu- 
tion of  sulphate  of  potash  is  prepared,  and  brought  to  the  atmos- 
pheric temperature  ;  a  condition  which  is  expedited  by  plunging 
the  vessel  which  contains  the  solution  into  a  basin  full  of  cold 
water,  ahd  stirring  it  until  the  thermometer  plunged  in  the  liquor 
indicates  that  the  temperature  of  the  latter  is  about  the  same  as, 
and  preferably  less  than,  that  of  the  air ;  because,  in  the  latter 
case,  it  may  be  quite  correctly  adjusted  by  grasping  the  vessel 
with  a  warm  hand.  In  order,  however,  to  secure  exactly  the  prop- 
er temperature,  the  whole  should  be  left  at  rest  for  a  few  min- 
utes after  having  withdrawn  the  vessel  from  the  basin  of  cold  water 
used  for  refrigerating  it,  taking  care  simply  to  stir  it  from  time 
to  time,  and  to  ascertain  that  the  thermometer  remains  at  the  same 
degree  of  temperature.  This  done,  the  liquor  is  filtered  into  a 
glass  cylinder,  c,  on  which  a  scratch,  h-i,  has  been  made,  cor- 
responding to  3,000  water-grains'  measure.  If  the  directions  given 
have  been  exactly  followed,  it  will  be  found  that  the  filtrate  is 
not  sufficient  to  fill  it  up  to  that  mark ;  the  necessary  volume, 
however,  should  be  completed  by  washing  the  deposit  of  sulphate 
of  potash  in  the  filter,  b,  with  a  saturated  solution  of  the  same  salt 
(sulphate  of  potash)  previously  prepared.  It  is  advisable  to  use  a 
saturated  solution  of  sulphate  of  potash  which  has  been  kept  for 
some  time,  and  not  one  immediately  prepared  for  the  purpose,  be- 
cause sulphate  of  potash,  in  dissolving,  produces  a  certain  amount 
of  cold,  which  would  create  delay,  since  it  would  be  necessary  to 
wait  until  the  temperature  of  the  mass  had  become  the  same  as 
that  of  the  air. 
64.  The  liquor  occupying  3,000  water-grains'  measure  in  the  cylinder,  should  be  next 
tendered  homogeneous  by  stirring  it  well,  after  which  the  natrometcr  may  be  immersed  in 


ALKALIMETRY. 


53 


it.  The  natrometer  is  simply  an  areometer  of  a  peculiar  construction,  provided  with  two 
scales :  the  one  of  a  pink  color  shows  the  degrees  of  temperature,  and  indicates,  for  each 
deo-ree  of  the  centigrade  thermometer,  the  level  at  which  a  solution  saturated  with  pure 
sulphate  of  potash  would  stand ;  on  the  other  scale,  each  degree  represents  1  per  cent,  of 
soda,  (oxide  of  sodium,)  as  represented  mfig.  21. 

65.  The  0^  of  the  two  scales  coincide  with  each  other.  If  the  experiment  take  place  at 
the  temperature  of  0°,  the  quantity  of  soda  will  be  directly  determined  by  observing  the 
number  of  deo-rees  on  the  soda  scale  ;  but  if  the  experiment  be  performed  at  25",  for  exam- 
ple it  will  be  seen  that  the  point  at  which  the  instrument  would  sink  in  the  liquor  saturated 
with  pure  sulphate  of  potash  corresponds  to  -p?^  of  soda ;  and,  in  this  case,  it  is  from  this 
point  that  the  0"  of  the  soda  scale  should  be  supposed  to  begin,  which  is  easily  accom- 
plished by  a  simple  subtraction,  as  will  be  seen  presently. 

66.  Experiment  having  shown  that  the  degrees  of  soda  cannot  be  equidistant,  but  that, 
on  the  contrary,  they  become  smaller  and  smaller  as  the  quantity  of  soda  increases,  the 
number  of  degrees  of  soda  are  obtained  as  follows  : — From  the  number  of  degrees  of  tem- 
perature now  indicated  on  the  pink  scale  of  the  natrometer,  subtract  the  number  of  degrees 
of  temperature  indicated  by  an  ordinary  thermometer  at  starting ;  then  look  at  the  soda 
scale  for  the  number  of  soda  degrees  which  correspond  to  the  number  of  degrees  of  tem- 
perature left  after  subtraction,  and  each  of  the  soda  degrees,  beginning  from  the  0°  of  the 
natrometer,  represents  1  per  cent. 

67.  For  example  : — Suppose  the  experiment  to  have  been  made  at  starting,  and  as 
indicated  by  an  ordinary  thermometer,  at  -\-  20°  centigrades,  and  that  the  level  of  the 
solution  is  now  found  to  stand  at  59"  on  the  pink  scale  of  temperature  of  the  natrometer, 
then  by  deducting  20  (the  original  temperature)  from  59  (number  of  degrees  indicated  by 
the  floating  point  on  the  pink  scale  of  temperatures  of  the  natrometer)  there  remains,  of 
course,  39.  Draw  the  instrument  out,  and  looking  now  on  the  said  pink  scale  for  39°,  there 
will  be  found  exactly  opposite,  on  the  soda  scale,  the  number  13,  which  number  signifies 
that  the  potash  under  examination  contains  13  per  cent,  of  soda,  (oxide  of  sodium.) 

68.  As  the  deposit  of  sulphate  of  potash  separated  by  filtering  might  retain  some  sul- 
phate of  soda,  it  is  advisable,  in  order  to  avoid  all  chance  of  error,  to  wash  it  with  a  saturated 
solution  of  sulphate  of  potash,  adding  as  much  of  it  as  is  necessary  to  bring  the  whole  mass 
of  the  liquor  up  to  the  mark  3,000  water-grains'  measures,  in  which  the  natrometer  being 
again  immersed,  the  minute  quantity  of  soda  indicated  should  be  added  to  the  percentage 
found  by  the  first  operation. 

69.  If  a  great  degree  of  accuracy  is  required,  the  fractions  of  degree  of  the  instrument 
must  be  taken  account  of ;  otherwise  they  may  be  neglected  with- 
out the  result  being  materially  affected,  sirfce  3  degrees  of  the  scale 
of  temperature  correspond  only  to  about  1  per  cent,  of  soda. 

70.  For  commercial  purposes,  the  process  may  be  slightly  varied, 
as  follows : — Take  500  grains  of  a  fliir  average  sample  of  the  potash 
to  be  examined,  previously  reduced  to  powder,  and  throw  them  into 
a  flask  ( fig.  22)  capable  of  containing  about  6,000  grains  of  water  ; 
pour  upon  them  about  2,000  grains  of  water,  and  shake  until  dis- 
solved. Add  now  sulphuric  acid  thereto  ;  this  will  produce  a  smart 
effervescence,  and  in  all  probability  a  deposit  of  sulphate  of  potash. 
We  say  in  all  probability,  because  it  is  clear  that  if  the  potash  in 
question  is  largely  adulterated  with  soda,  or  was  altogether  nothing 
else  than  carbonate  of  soda,  as  has  occasionally  happened,  it  is  evi- 
dent that  no  deposit  of  sulphate  of  potash  would  take  place  ;  and 
yet,  as  it  is  necessary  to  the  success  of  the  operation  that  the  liquor 
should  contain  an  excess  of  this  latter  salt,  a  certain  quantity  of  it 
previously  reduced  to  fine  powder  must  in  that  case  be  purposely 
added  to  the  solution. 

71.  After  the  disengagement  of  gas  has  ceased,  it  is  necessary 
to  pour  the  dilute  acid  cautiously,  and  only  drop  by  drop,  until  the 
neutralizing  point  is  correctly  hit,  which  will  be  known  as  usual  by 
testing  with  litmus-paper.  But  if,  by  accident,  too  much  acid  has 
been  used,  which  is  known  by  the  reddening  of  the  litmus-paper, 
the  slight  overdose  may  be  neutralized  by  adding  a  small  quantity 
of  weak  solution  of  potash. 

72.  As  this  reaction  produces  heat,  it  is  necessary  to  lower  the 
licjuor  down  to  the  temperature  of  the  atmosphere,  decant  in  a  filter 
placed  over  the  gla«s  cylinder,  and  fill  it  up  to  the  scratch  3,000,  by 
washing  the  residue  on  the  filter  with  a  saturated  solution  of  sul- 
phate of  potash,  exactly  as  described  in  i^  63. 

73.  The  glass  cylinder  iieing  properly  filled  up  to  the  scratch,  remove  the  funnel,  close 
the  orifice  of  the  glass  cylinder  with  the  palm  of  the  hand,  and  shake  the  whole  violently  • 


54 


ALKALIMETRY. 


hold"  —  the  natrometer,  which  should  be  perfectly  clean,  by  its  upper  extremity,  slowly 
imm^..^e  it  in  the  solution.  If  the  potash  under  examination  be  pure,  the  pink  scale  will 
indicate  the  degree  of  temperature  at  which  the  experiment  has  been  made,  taking  the 
under  line  as  the  true  level  of  the  liquid  ;  but  if,  on  the  contrary,  it  contains  soda,  the  pink 
scale  of  temi)eratures  will  indicate  a  few  degrees  more  than  the  real  temperature,  and  this 
surplus  number  of  degrees,  being  compared  with  those  of  the  soda  scale  contiguous  to  it, 
on  the  opposite  side,  will  express  the  percentage  of  soda  present  iu  the  sample. 

74.  For  example  : — Suppose  the  experiment  to  have  been  made  at  -f- 12  centigrade,  and 
to  have  given  a  solution  marking  25"  on  the  pink  scale  of  temperatures  of  the  natrometer, 
that  is,  13"  more  than  the  real  temperature  ; — looking  therefore  at  number  13  on  the  pink 
scale  of  temperature,  it  will  be  seen  that  the  number  exactly  opposite  on  the  soda  scale,  and 
corresponding  to  it,  is  4,  which  indicates  that  the  sample  of  potash  examined  contains  4  per 
cent,  of  soda. 

It  is  important  to  bear  in  mind  that  all  commercial  potashes  contain  naturally  a  small 
quantity  of  soda,  which  quantity,  in  certain  varieties,  may  even  be  considerable ;  it  is  only 
when  the  proportion  of  soda  is  more  considerable  than  that  which  is  naturally  contained  in 
the  species  of  potash  submitted  to  analyisis,  that  it  should  be  considered  as  fraudulently 
added.  The  following  table,  published  by  M.  Pesier,  shows  the  average  composition  of  the 
principal  varieties  of  potash  found  in  commerce,  when  in  an  unadulterated  state. 

Average  Composition  of  Potashes. 


i 

.3 

St 
i 

_2 

s, 

1 

< 

S. 

1 

> 

S. 

Potashe 
ej  in  th 

iobtain- 
e  Labo- 

■-5  c 
>.'Z 

i  t 

1     *  " 

1     a 

1     EO 

1851. 

1835. 

cining. 

p.  g 

s. 

•a 

*C   » 
§■1 

s. 

.1  II 

:1l£- 

i  |i5 

Si  ° 

Sulpbate  of  poUiih 
Chloride  of  potassium    - 
Carbonate  of  putash 
Carbonate  of  soda  (dry) 
Insoluble  residue   - 
Moisture         -        .        -        - 

Phosphoric  acid,  lime,  silica,  &c. 
Alkalimetric  degrees 

13-47 
0-95 

74-10 
3-01 
0-65 
7 -28 

0-54 

14-11  15-32 
2-09     S-15 
69-61  CS-07* 
8-09     5-85 
1-21     3-35 
8-S2  unde- 
1    ter- 
mined 
107,  ditto 

14.3S    3S-S4 
3-64      9-16 

71 -3S;    8S-C3 
2-3l!     4-17 
0-44'     2.66 
4-56      5.34 

»  3-29<     1-20 

4-27 
18.17 
51-83 
24-17 

1-56 

2-98 
19-69 
53-90 
23-17 

0-20 

16-19 

i    33-89 

26-64 

19-60 

3-6S 

1-50 

1-60 

89-95 

5-12 

0-50 
1-33 

0-70 
1-70 
95-24 
2-12 

0-24 

100-00 

100-00 

100-00  100-00  100-00 

100.00 

10000 

100  00 

100-00 

56 

53  1  1     55 

54-4  ^   31-6 

CO     1   59-7 

36.5 

6S-5 

69-5 

75.  Tlie  alkalimctrical  assai/  of  soda  is  performed  exactly  in  the  same  manner  as  that 
of  potash — that  is  to  say :  From  a  fair  average  sample  of  the  soda  to  be  examined,  take 
1,000  grains'  weight,  (or  less,  if  that  quantity  cannot  be  spared)  and  boil  it  five  or  six 
minutes  in  about  eight  fluid  ounces  of  water ;  filter,  in  order  to  separate  the  insoluble  por- 
tion, and  wash  the  residue  on  the  filter  with  boiling  water  until  it  no  longer  drops  from  the 
filter  with  an  alkaline  reaction,  and  the  bulk  of  the  filtered  liquid  and  the  washings  received 
in  a  graduated  glass  cylinder  form  10,000  grains'  measure.  Should  the  water  which  may 
have  been  required  to  wash  the  residue  have  increased  the  bulk  of  the  solution  beyond  that 
quantity,  it  should  be  evaporated  to  reduce  it  to  the  bulk  mentioned. 

76.'  This  being  done,  1,000  water-grains'  measure — that  is  to  say,  ^\  part  of  the 
aqueous  solution  of  the  soda  ash  above  mentioned  (§  75) — is  transferred  to  the  glass 
beaker  or  ves.^el  in  which  the  Saturation  is  intended  to  take  place,  it  is  tinged  distinctly  blue 
WMth  tincture  of  litmus,  and  the  operation  is  performed  in  the  same  manner  and  with  the 
same  precautions  as  for  potash  ;  the  glass  beaker  containing  the  blue  alkaline  solution  being 
placed  upon  a  sheet  of  white  paper,  or  a  slab  of  white  porcelain,  the  better  to  observe  the 
change  of  color  which  takes  place  when  the  satuniting  point  is  ajiproaching. 

77.  Having  put  into  a  glass  l)caker  the  1,000  grains'  measure  of  the  aqueous  solution  of 
soda  ash  to  be  examined,  (§  75,)  and  of  the  l<st  sulphuric  arid  for  soda,  described  before, 
(§§  23-27,)  the  alkalimeter*^ /y.f.  12,  13,  14,  should  be  filled  w'ith  that  test  acid  up  t  the 
point  marked  0',  (taking  the  under  line  of  the  liquid  as  the  true  level,)  and  poured  ther  f.cm 
with  the  precaution  already  indicated,  stirring  briskly,  at  the  same  time,  the  liquid  i  -.he 
beaker.      As  is  the  case  with  the  alkalimetrical  assay  of  potash,  the  carbonic  acid  expelled 

*  In  the  impos-sibility  of  estimating  exactly  the  loss  by  calcin-ation,  and  the  quantity  of  oxide  of 
pota-ssium  in  the  cau.stic  state,  (hydrate  of  potash,)  we  have  reduced  the  potash  to  the  state  of  carbon- 
Ite,  to  make  comparison  more  ca~y. 


ALKALIMETRY.  55 

by  the  test  acid  reacting  upon  the  as  yet  undecomposed  portion  of  the  soda  ash,  converts  it 
into  bicarbonate  of  soda,  so  that  at  first  no  effervescence  is  produced  ;  but  as  soon  as  half 
the  quantity  of  the  soda  in  the  solution  is  saturated,  a  brisk  elfervescence  takes  place.  At 
first,  therefore,  the  operator  may  pour  at  once,  without  fear,  a  pretty  large  quantity  of  the 
test  acid  into  the  alkaline  solution,  but  as  soon  as  this  effervescence  makes  its  appearance, 
he  sliould  proceed  with  increased  precaution  gradually  as  the  saturating  point  is  approached. 
The  modus  operandi  is,  in  fact,  precisely  as  already  detailed  for  the  assay  of  potash,  pre- 
cisely the  same  kind  and  amount  of  care  is  requisite,  and  the  assay  is  known  to  be  termi- 
nated when  the  streaks  made  upon  the  litmus-paper  with  the  stirring  rod  remain  distinctly 
and  permanently  of  a  pink  color. 

78.  After  saturation,  and  after  having  allowed  the  sides  of  the  alkalimetcr  to  drain,  the 
number  of  divisions  at  which  the  test  acid  stands  in  the  alkalimeter  indicate  at  once  the 
percentage  of  the  soda  assayed,  since,  as  we  said,  each  division  of  this  particular  test  acid 
represents  one  grain  of  pure  soda.  If,  therefore,  the  test  acid  stands  at  52  in  the  alkalimeter, 
then  the  soda  assayed  contained  52  per  cent,  of  real  soda.  See,  besides,  the  observations 
of  §  48  and  following,  and  also  §  81. 

79.  If,  instead  of  the  special  test  acid  for  soda  just  alluded  to,  the  operator  employs  that 
which  has  a  specific  gravity  of  1'032,  and  100  alkalimetrical  divisions  of  which  saturate  one 
equivalent  of  each  base,  the  modus  operandi  is  the  same — that  is  to  say,  the  alkalimeter  is 
filled  with  it  up  to  0",  and  it  is  poured  therefrom  carefully  into  the  alkaline  solution  ;  but 
as  the  equivalent  of  soda  is  31,  and  100  alkalimetrical  divisions  of  the  test  sulphuric  acid 
now  employed  are  capable  of  saturating  only  that  quantity  of  soda,  it  is  clear  that  with  the 
soda  ash  taken  as  an  example  in  the  preceding  case,  and  containing  52  per  cent,  of  real  soda, 
the  operator  will  have  to  refill  his  alkalimeter  with  the  same  test  acid,  and  that  a  certain 
number  of  divisions  of  this  second  filling  will  have  to  be  employed  to  perfect  the  saturation. 
In  this  instance  the  operator  will  find  that  nearly  C8  divisions  more,  altogether  1G8  divisions 
(correctly,  1G7'  74)  have  been  required  to  effect  the  saturation. 

80.  If,  instead  of  the  special  test  sulphuric  acid  for  soda,  (§§  23-27,)  or  the  test  sulphuric 
acid  for  potash,  soda,  and  other  bases,  (i?§  31-34,)  the  operator  uses  the  potash  and  soda 
alkalimeter,  (§§  28-35,)  the  method  is  always  the  same  (§^  74,  75) — that  is  to  say,  the 
aqueous  solution  of  the  soda  ash  is  poured  into  the  glass  beaker,  the  difference  being  merely 
that  instead  of  the  alkalimeter  being  quite  filled  up  with  the  test  sulphuric  acid,  which,  in 
the  present  instance,  has  a  specific  gravity  of  1*268  (§  29),  the  said  test  acid  is  poured  into 
the  alkalimeter  only  up  to  the  point  marked  "  so(/a,"  (taking  the  under  line  of  the  liquid  as 
the  true  level,)  and  the  remaining  divisions  of  the  alkalimeter  are  carefully  filled  up  with 
water.  The  mouth  of  the  tube  should  then  be  thoroughly  closed  with  the  thumb  of  the  left 
hand,  and  the  whole  violently  shaken  until  perfectly  mixed,  taking  great  care,  of  course, 
not  to  squirt  any  of  the  acid  out  of  the  tube,  which  evidently  would  cause  an  amount  of 
error  proportionate  to  the  quantity  of  the  test  acid  which  would  have  thus  been  lost.  The 
acid  should  then  be  poured  from  the  alkalimeter  with  the  usual  precaution  (§  76)  into  the 
glass  beaker  containing  the  aqueous  solution  of  the  soda  ash  under  examination,  until  com- 
plete neutralization  is  attained,  stirring  briskly  all  the  time,  or  after  each  addition  of  the 
test  acid.  The  neutralization  point  being  hit,  the  sides  of  the  alkalimeter  are  allowed  to 
drain,  and  the  operator  then  reads  off  the  number  of  divisions  employed,  which  number 
indicates  the  percentage  of  real  soda  contained  in  the  sample  assayed.  Thus,  if  the  sample 
operated  upon  be  the  same  as  that  alluded  to  before,  the  number  of  divisions  employed 
being  52  would  indicate  52  per  cent,  of  real  soda. 

81.  If  the  operator  wishes  to  estimate  the  amount  of  soda  in  the  sample  as  carbonate  of 
soda,  he  should  fill  the  alkalimeter  with  the  test  acid  in  question  (specific  gravity  1-268)  up 
to  the  point  marked  carbonate  of  soda,  and  fill  the  remaining  divisions  with  water,  shake  the 
whole  well,  and  proceed  with  the  neutralization  of  the  aqueous  solution  of  the  sample  in  the 
glass  beaker  as  just  described.  Supposing,  as  before,  that  the  sample  in  question  contains 
52  per  cent,  of  real  soda,  it  will  now  be  found  that  the  number  of  divisions  employed 
altogether  to  saturate  the  sample  completely  are  very  nearly  89,  for  52  of  caustic  soda 
correspond  to  88-90  of  the  carbonate  of  that  alkali. 

82.  If  the  soda  ash  is  very  poor,  instead  of  operating  upon  1,000  water-grains'  measure, 
or  one-tenth  part  of  the  whole  solution,  (=  100  grains'  weight  of  the  soda  ash,  §§  70-77,) 
it  is  advisable  to  talce  three  or  four  thousand  water-grains'  measure  of  the  alkaline  solution, 
and  to  divide,  by  three  or  four,  the  result  obtained  by  saturation.  Suppose,  for  oxamiile, 
that  the  quantity  of  real  soda  found  is  46;  this,  if  only  1,000  grains'  measure  had  In-en 

■  taken,  would,  of  course,  indicate  46  per  cent.  ;  but  as  4,000  water-grains'  measure  of  solu- 
tion has  been  taken  instead,  that  number  46  must,  accordinglv,  be  divided  by  4,  which 
gives  lU  per  cent,  only  of  real  soda  contained  in  the  sample  under  examination. 

83.  The  soda  ash  of  commerce  contains  generally  a  percentage  of  insoluble  substances, 
wliicii  are  removed  by  filtering,  as  we  said,  and  a  greater  or  less  quantity  of  chloride  of 
sodium  (connuon  salt)  and  of  sulphate  of  soda,  which,  however,  do  not  in  the  slightest  degree 
interfere  with  the  accuracy  of  the  result.     But  there  is  a  source  of  error  resulting  from  the 


56  ALKALIMETRY. 

presence  in  the  soda  ash  of  sulphuret  of  calcium,  of  sulphite,  and  sometimes  also,  though 
more  rarely,  of  hyposulphite,  of  soda.  When  sulphuret  of  calcium  is  present  in  the  ash,  on 
heating  the  latter  by  hot  water,  a  double  decomposition  takes  place,  the  sulphuret  of  cal- 
cium reacting  upon  the  carbonate  of  soda,  forms  sulphuret  of  sodium  and  carbonate  of  lime. 
Now  sulphuret  of  sodium  saturates  the  test  acid  just  as  carbonate  of  soda  ;  but  as  it  has  no 
commercial  value,  it  is  clear  that  if  the  ash  contains  a  quantity  of  the  useless  sulphuret  at 
all  considerable,  a  very  serious  damage  may  be  sustained  by  the  purchaser  if  the  percentage 
of  that  substance  present  in  the  ash  be  taken  account  of  as  being  soda.  Sulphite  of  soda  is 
produced  from  the  o.xidization  of  this  sulphuret  of  sodium,  and  is  ol)jectionable  inasmuch 
that,  when  the  test  acid  is  added  slowly  to  the  aqueous  solution  of  the  ash,  the  efl'ect  is  to 
convert  the  sulphite  into  bisulphite  of  soda,  before  any  evolution  of  sulphuric  acid,  and  con- 
sequently before  the  pink  reaction  on  litmus-paper  is  produced. 

84.  in  order  to  obviate  the  inaccuracies  resulting  from  the  neutralization  of  a  portion  of 
the  test  acid  by  these  substances,  it  is  necessary  to  convert  them  into  sulphates  of  soda, 
which  is  easily  done  by  calcining  a  quantity  of  the  sample  with  five  or  six  per  cent,  of 
chlorate  of  potash,  as  recommended  by  Gay-Lussac  and  Welter.  The  operator,  therefore, 
should  intimately  mix  50  or  60  grains'  weight  of  pulverized  chlorate  of  potash  with  l,0(iO 
grains  of  the  pulverized  sample,  and  fuse  the  mixture  in  a  platinum  crucible,  for  which 
purpose  a  blowpipe  gas-furnace  will  be  found  exceedingly  convenient.  The  fused  mass 
should  be  washed,  and  the  filtrate  being  received  into  a  10,000  water-grains'  measure,  and 
made  up  with  water  to  occupy  that  bulk,  may  then  be  assayed  in  every  respect  as  described 
before  with  one  or  other  of  the  test  acids  mentioned. 

85.  When,  however,  the  soda  ash  contains  some  hyposulphite  of  soda — which  fortunately 
is  seldom  the  case,  for  this  salt  is  very  difficultly  produced  in  presence  of  a  very  large  excess 
of  alkali — it  should  not  be  calcined  with  chlorate  of  potash,  because  in  that  case  one  equiv- 
alent of  hyposulphite  becomes  transformed  iiot  into  one  equivalent  of  sn/p/iafe,  but,  reacting 
upon  one  equivalent  of  carbonate  of  soda,  expels  its  carbonic  acid,  and  forms  with  the  soda 
of  the  decomposed  carbonate  a  second  equivalent  of  sulphate  of  soda,  each  equivalent  of 
hyposulphite  becoming  thus  converted  into  two  equivalents  of  sulphate,  and  therefore  creat- 
ing an  error  proportionate  to  the  quantity  of  the  hyposulphite  present,  each  equivalent  of 
which  would  thus  destroy  one  equivalent  of  real  and  available  alkali,  and  thus  render  the 
estimation  of  the  sample  inaccurate,  and  possibly  to  a  very  considerable  extent. 

80.  When  this  is  the  case,  it  is  therefore  advisable,  according  to  Messrs.  Fordos  and 
Gelis,  to  change  the  condition  of  the  sulphurets,  sulphites,  and  hyposulphites,  by  adding  a 
little  neutral  chromate  of  potash  to  the  alkaline  solution,  whence  result  sulphate  of  chro- 
mium, water,  and  a  separation  of  sulphur,  which  will  not  aflect  the  accuracy  of  the  alkahmet- 
rical  process. 

87.  Whether  the  sample  to  be  analyzed  contains  any  sulphuret,  sulphite,  or  hyposul- 
phite, is  easily  ascertained  as  follows : — If,  on  pouring  sulphuric  acid  upon  a  portion  of  the 
sample  of  soda  ash  under  examination,  an  odor  of  sulphuretted  hydrogen — that  is,  an  odor 
of  rotten  eggs — is  evolved,  or  if  a  portion  of  the  soda  ash,  being  dissolved  in  water,  and 
then  filtered,  produces  a  black  precipitate  (sulphuret  of  lead)  when  solution  of  acetate  of 
lead  is  poured  into  it,  then  the  sample  contains  a  sulphuret. 

88.  And  if,  after  adding  to  some  dilute  sulphuric  acid  as  much  bichromate  of  potash  as 
is  necessary  to  impart  to  it  a  distinct  reddish-yellow  tinge,  and  a  certain  quantity  of  the  solu- 
tion of  the  soda  ash  under  examination  being  poured  into  it,  but  not  in  sufficient  quantity  to 
neutralize  the  acid,  the  reddish-yellow  color  becomes  green,  it  is  a  proof  that  the  sample 
contains  either  sulphite  or  hyposulphite  of  soda,  the  green  tinge  being  due  to  the  transforma- 
tion of  the  chromic  acid  into  sesquioxide  of  chromium. 

89.  And  if,  muriatic  acid  being  poured  into  the  clear  solution  of  the  soda  ash,  a  turbid- 
ness  supervenes  after  some  time  if  left  at  rest,  or  at  once  if  heat  is  applied,  it  is  due  to  a 
deposit  of  sulphur,  an  odor  of  sulphurous  acid  being  evolved,  and  hyposulphite  of  soda  is 
probably  present.  We  say  probably,  because  if  sulphurets  and  sulphites  are  present,  the 
action  of  muriatic  acid  would  decompose  both,  and  liberate  sulphuretted  hydrogen  and  sul- 
phurous acid  ;  but  as  these  two  gases  decompose  each  other,  a  turbidness  due  to  a  separation 
of  sulphur  is  also  formed  ;  thus  2HS  +  S  0^  =  2H0  -f  2S. 

90.  As  we  have  already  had  occasion  to  remark,  the  soda  ash  of  commerce  frequently 
contains  some,  and  occasionally  a  large  quantity  of  caustic  soda,  the  proportion  of  which  is 
at  times  important  to  determine.  This  may  be  done,  according  to  Mr.  Barreswill,  by 
adding  a  solution  of  chloride  of  barium  to  the  aqueous  solution  of  the  soda  ash,  by  which 
the  carbonate  of  soda  is  converted  into  carbonate  of  barytes,  whil.«t  the  caustic  soda,  react- 
ing upon  the  chloride  of  barium,  liberates  a  quantity  of  caustic  barytes  proportionate  to  that 
of  the  caustic  soda  in  the  soda  a.sh.  After  this  addition  of  chloride  of  barium,  the  liquor  is 
filtered  in  order  to  separate  the  precipitated  carbonate  of  barytes  produced,  and  which  re- 
mains on  the  filter,  on  whieh  it  should  be  washed  with  pure  water.  A  few  lumps  of  chalk 
arc  then  put  into  a  Florence  flask,  a,  and  some  muriatic  acid  being  poured  upon  it,  an 
effervescence  due  to  a  disengagement  of  carbonic  acid  is  produced,  the  flask  is  then  closed 


ALKALIMETRY. 


57 


with  a  good  cork,  provided  with  a  bent  tube,  6,  reaching  to  the  bottom  of  the  vessel,  <■,  and 
the  stream  of  carbonic  acid  produced  is  then  passed  through  the  liquor,  c,  filtered  from  the 
carbonate  of  barytes  above  mentioned.  The  stream  of  car- 
bonic acid  produces  a  precipitate  of  carbonate  of  barytes, 
which  should  be  also  collected  on  a  separate  filter,  washed, 
dried,  and  weighed.  Each  gain  of  this  second  precipitate  of 
carbonate  of  barytes  corresponds  to  0-3157  of  caustic  soda. 

91.  As  the  soda  ash  of  commerce  almost  invariably  con- 
tains earthy  ciu-bonates,  the  sample  operated  upon  should 
always  be  dissolved  in  hot  water,  and  filtered,  in  order  to 
separate  the  carbonate  of  lime,  which  otherwise  would  saturate 
a  proportionate  quantity  of  the  test  acid,  and  thus  render  the 
analysis  worthless. 

92.  The  quantity  of  water  contained  in  either  potash  or 
soda  ash  is  ascertained  by  heating  a  weighed  quantity  of  the 
sample  to  redness  in  a  covered  platinum  capsule  or  crucible. 
The  loss  after  ignition  indicates  the  proportion  of  water.     If 

any  caustic  alkali  is  present,  1  equivalent,  =9  of  water,  is  retained,  which  cannot  be  thus 
eliminated,  but  which  may,  of  course,  be  determined  by  calculation  after  the  proportion  of 
caustic  soda  has  been  found,  as  shown  before,  each  31  grains  of  caustic  soda  containing  9 
grains  of  water. 

93.  Besides  the  alkalimetrical  processes  which  have  been  explained  in  the  preceding 
pages,  the  proportion  of  available  alkali  contained  in  the  sample  may  be  estimated  from  the 
amount  of  carbonic  acid  which  can  be  expelled  by  supersaturating  the  alkali  with  an  acid. 
The  determination  of  the  value  of  alkalis,  from  the  quantity  of  carbonic  acid  thus  evolved  by 
the  supersaturation  of  the  carbonate  acted  upon,  has  long  been  known.  Dr.  Ure,  in  the 
"Annals  of  Philosophy,"  for  October,  1817,  and  then  in  his  "  Dictionary  of  Chemistry," 
1821,  and  more  recently  in  his  pamphlet  "  Chemistry  Simplified,"  described  several  instru- 
ments for  analyzing  earthy  and  alkaline  carbonates,  for  a  description  of  which  the  reader  is 
referred  to  the  article  on  Aciiumetky.  The  ingenious  little  apparatus  of  Drs.  Frcsenius 
and  Will  for  the  same  purpose,  and  to  which  we  have  already  alluded  in  the  same  article, 
gives  accurate  results  ;  but  it  should  be  observed  that  when  the  potash  or  soda  of  commerce 
contains  any  caustic  alkali,  or  bicarbonate,  or  earthy  carbonates,  or  sulphuret  of  alkali — 
which,  as  we  have  seen,  is  frequently,  and,  indeed,  almost  invariably,  the  case,  the  process 
is  no  longer  applicable  without  first  submitting  the  sample  to  several  operations — which 
ronder  this  process  troublesome  and  unsuited  to  unpractised  hands.  Thus,  if  caustic  potash 
is  present,  the  sample  must  be  first  mixed  and  triturated  with  its  own  weight  of  pure  quartz- 
ose  sand  and  about  one-third  of  its  weight  of  carbonate  of  ammonia.  The  mass  is  then 
moistened  with  aqueous  ammonia,  and  then  put  into  a  small  iron  capsule  and  evaporated  to 
dryness,  so  as  to  expel  completely  the  ammonia  and  carbonate  of  ammonia.  The  mass  is 
then  treated  by  water,  filtered,  washed,  and  concentrated  to  a  proper  bulk  by  evaporation, 
transferred  to  the  apparatus,  and  treated  as  will  be  seen  presently.  If  the  sample  contains 
caustic  soda,  instead  of  one-third,  at  least  half  of  its  weight  of  carbonate  of  ammonia  should 
be  employed.  But  for  the  estimation  o^  pure  carbonates,  Drs.  Fresenius  and  Will's  method 
is  both  accurate  and  easy.     The  apparatus  consists  of  two 

flasks,  A  and  n  ;  the  first  should  have  a  capacity  of  from 
two  to  two  ounces  and  a  half ;  the  second,  or  flask  n,  should 
be  of  a  somewhat  smaller  size,  and  hold  about  one  and  a 
half  or  two  ounces.  Both  should  be  provided  with  per- 
fectly sound  corks,  each  perforated  with  two  holes,  through 
which  the  tubes  a,  c,  d,  are  passing.  The  lower  extremity 
of  the  tube  a  must  be  adjusted  so  as  to  reach  nearly  to 
the  bottom  of  the  flask  a,  and  its  upper  extremity  is  closed 
by  means  of  a  small  pellet  of  wax,  6 ;  c  is  a  tube  bent  twice 
at  right  angles,  one  end  of  which  merely  protrudes  through 
the  cork  into  the  flask  a,  but  the  other  end  reaches  nearly 
to  the  bottom  of  the  flask  n.  The  tube  d  of  the  flask  d 
merely  protrudes  through  the  cork  into  the  flask. 

91.  The  apparatus  being  so  constructed,  a  certain  quan- 
tity— 100  grains,  for  example — of  the  potash  or  soda  ash 
under  examination,  (and  whieh  may  have  been  previously 
dried,)  is  weighed  and  introduced  into  the  flask  a,  and  water 
is  next  poured  into  this  fl;isk  to  about  one-third  of  its  cajTacity.  Into  the  other  flask,  or 
flask  n,  concentrated  ordinary  sulphuric  acid  is  poured,  and  the  corks  are  firmly  put  in  the 
fl;u*ks,  whieh  thus  become  connected,  so  as  to  form  a  twin-apparatu.s,  which  is  then  car- 
ried to  a  delicate  balance,  and  accurately  weighed.  This  done,  the  operator  removes  the 
apparatus  from  the  balance,  and  applying  his  lijis  to  the  extremity  of  tiie  tube  d,  sucks  out 


58  ALKALINE  EAETHS. 

a  few  air-bubbles,  which,  as  the  other  tube,  a,  is  closed  by  the  wax  pellet,  rarefies  the  air  in 

the  flask  a,  and  consequently  causes  the  sulphuric  acid  of  flask  b  to  ascend  a  certain  height 
(after  the  suction)  into  the  tube  c  ;  and  if,  after  a  short  time,  the  column  of  sulphuric  acid 
maintains  its  height  in  the  tube  <•,  it  is  a  proof  that  the  apparatus  is  air-tight,  and  therefore 
as  it  sliould  be.  This  being  ascertained,  suction  is  again  applied  to  the  extremity  of  the 
tube  (/,  so  that  a  portion  of  the  sulphuric  acid  of  the  flask  b  ascends  into  the  tube  c,  and 
presently  falls  into  the  flask^A  ;  the  quantity  which  thus  passes  over  being,  of  course,  pro- 
portionate to  the  vacuum  produced  by  the  suction.  As  soon  as  the  acid  thus  falls  in  the 
water  containing  the  alkaline  carbonate  in  the  flask  a,  an  effervescence  is  immediately  pro- 
duced, and  as  the  carbonic  acid  disengaged  must,  in  order  to  escape,  pass,  by  the  tube  c, 
through  the  concentrated  sulphuric  acid  of  the  flask  b,  it  is  thereby  completely  dried  before 
it  can  finally  make  its  exit  through  the  tube  d.  The  efi"ervescence  having  subsided,  suction 
is  again  applied  to  the  tube  J,  in  order  to  cause  a  fresh  quantity  of  sulphuric  acid  to  flow 
over  into  the  flask  a,  as  before ;  and  so  on,  till  the  last  portion  of  sulphuric  acid  sucked 
over  produces  no  effervescence,  which  indicates,  of  course,  that  all  the  carbonate  is  decom- 
posed, and  that,  consequently,  the  operation  is  at  an  end.  A  powerful  suction  is  now  ap- 
plied to  the  tube  d,  in  order  to  cause  a  tolerably  large  quantity  of  sulphuric  acid,  but  not 
all,  to  flow  into  the  flask  a,  which  thus  becomes  very  hot,  from  the  combination  of  the 
concentrated  acid  with  the  water,  so  that  the  carbonic  acid  is  thereby  thoroughly  expelled 
from  the  solution.  The  little  wax  peUet  which  served  as  a  stopper  is  now  removed  from 
the  tube  a,  and  suction  applied  for  some  time,  in  order  to  sweep  the  flasks  with  atmos- 
pheric air,  and  thus  displace  all  the  carbonic  acid  in  the  apparatus,  which  is  allowed  to 
become  quite  cold,  and  weighed  again,  together  with  the  wax  pellet,  the  difference  between 
the  first  and  the  second  weighing — that  is  to  say,  the  loss — indicating  the  quantity  of  car- 
bonic acid  which  was  contained  in  the  carbonate,  which  has  escaped,  and  from  which,  of 
course,  the  quantity  of  the  carbonated  alkali  acted  upon  may  be  calculated.  Suppose,  in 
effect,  that  the  loss  is  19  grains  :  taking  the 

Equivalent  of  soda  -         -        -        -         -         -=31 

do  carbonic  acid =22 

1  equivalent  of  carbonate  of  soda        -        -      =  53, 

it  is  clear  that  the  19  grains  of  carbonic  acid  which  have  been  expelled  represent  45-7Y 
grains  of  carbonate  of  soda,  or,  in  other  words,  100  grains  of  soda  ash  operated  upon  con- 
tained 45'77  of  real  carbonate  of  soda,  thus  : — 

CO''    NaO'  CO^     CO^  NaO'  CO^ 

22      :      53     ::     19      :      a;     =     45-77 

95.  As  the  soda  ash  of  commerce  always  contains  earthy  carbonates,  and  very  frequently 
sulphurets,  sulphites,  and  occasionally  hyposulphites,  instead  of  putting  the  100  grains  to 
be  operated  upon  directly  into  the  flask  a,  it  is  absolutely  necessary  first  to  dissolve  them  in 
boiling  water,  to  filter  the  solution,  and  to  wash  the  precipitate  which  may  be  left  on  the 
filter  with  boiling  water.  The  solution  and  the  washings  being  mixed  together,  should  then 
be  reduced  by  evaporation  to  a  proper  volume  for  introduction  into  the  flask  a,  and  the 
process  is  then  carried  on  as  described.  If  sulphuret,  sulphites,  or  hyposulphites  are 
present,  the  ash  should  be  treated  exactly  as  mentioned  in  §§  83-91,  previous  to  pouring 
the  solution  into  the  flask  a,  since  otherwise  the  sulphuretted  hydrogen  and  sulphurous  acid, 
which  would  be  disengaged  along  with  the  carbonic  acid,  would  apparently  augment  the 
proportion  of  the  latter,  and  render  the  result  quite  erroneous. 

96.  The  balance  used  for  this  mode  of  analysis  should  be  capable  of  indicating  small 
weights  when  heavily  laden. — A.  N. 

ALKALINE  EARTHS — Barttes,  Lime,  and  Stroxtta.  These  earths  are  so  called  to 
distinguish  them  from  the  earths  Magnesia  and  Alumina.  They  are  soluble  in  water,  but 
to  a  much  less  extent  than  the  alkalies.  Their  solutions  impart  a  brown  color  to  turmeric 
paper,  and  neutralize  acids.  They  are,  however,  distinguished  from  the  alkalies  by  their 
combination  with  carbonic  acid,  being  nearly  insoluble  in  water. 

AL-KENNA,  or  AL-HEXNA,  is  the  name  of  the  root  and  leaves  of  Laivsonia  inermis, 
which  have  been  long  employed  in  the  East  to  dye  the  nails,  teeth,  hair,  garments,  &c. 
The  leaves,  ground,  and  mixed  with  a  little  limewatcr,  serve  for  dyeing  the  tails  of  horses 
in  Persia  and  Turkey. 

It  is  the  same  a.s  the  herb  Tlenna  frequently  referred  to  by  the  Oriental  poets.  The 
powder  of  the  leaves,  being  wet,  forms  a  paste,  which  is  bound  on  the  nails  for  a  night,  and 
the  color  thus  given  will  last  for  several  weeks. 

This  plant  is  sometimes  called  the  true  alkanet  root,  the  alkanet  of  the  shops  being 
termed  tlie  spurious  alkanrt  root,  {radix  alkannce  spurice.) 

ALLIOLE.  One  of  the  hydrocarbons  which  can  be  obtained  from  naphtha.  It  is  one 
bf  the  most  volatile  of  bodies.     Alliolc  is  obtained  by  distilling  crude  naphtha,  and  collect- 


ALLOY 


59 


ing  all  that  leaves  the  still  in  the  first  distillation  before  the  boiling  temperature  reaches 
194°  F ;  and  on  the  second  distillation,  all  below  176'  F.  This  substance  combines  with, 
or  is  altered  by,  oil  of  vitriol,  and  hence  it  is  better  obtained  from  the  crude  naphtha,  and 
afterwards  purified  by  agitation  with  dilute  sulphuric  or  hydrochloric  acid,  and  redistillation. 
It  boils  when  nearly  free  from  benzole,  at  a  temperature  of  from  140°  to  158°  F.,  and 
possesses  an  alliaceous  odor  somewhat  resembling  sulphide  of  carbon. — Richardson. 

ALLOTROPY.  AUotrojnc  Condition.  A  name  introduced  by  Berzelius  to  signify 
another  form  of  the  same  substance,  derived  from  S\Aos,  another,  and  rpoTros,  habit.  Car- 
bon for  example,  exists  as  the  diamond,  a  brilliant  gem,  with  difficulty  combustible ;  as 
graphite,  a  dark,  heavy,  opaque  mass,  often  crystalline,  also  of  great  infusibility ;  and  as 
charcoal,  a  dark  porous  l^ody,  which  burns  with  facility. 

An  extensive  series  of  bodies  appears  to  assume  similar  allotropic  modifications.  The 
probability  is  that,  with  the  advance  of  physical  and  chemical  science,  many  of  the 
substances  now  supposed  to  be  elementary  will  be  proved  to  be  but  allotropic  states  of  some 
one  form  of  matter.  Deville  has  already  shown  that  silicon  and  boron  exist,  like  the  dia- 
mond, in  three  allotropic  states— one  of  the  conditions  of  boron  being  much  harder  than  the 
diamond. 

ALLOY.  The  experiments  of  Crookewitt  upon  amalgams  appear  to  prove  that  the 
combination  of  metals  in  alloys  obeys  some  laws  of  a  similar  character  to  those  which 
prevail  between  combining  bodies  in  solution ;  i.  c.  that  a  true  combining  proportion 
existed. 

By  amalgamation  and  straining  through  chamois  leather,  ho  obtained  crystalline  metallic 
compounds  of  gold,  bismuth,  lead,  and  cadmium,  with  mercury,  which  appeared  to  exist  in 
true  definite  proportions.  With  potassium  he  obtained  two  amalgams,  KHg""  and  Kllgl 
With  silver,  by  bringing  mercury  in  contact  with  a  solution  of  nitrate  of  silver,  according 
to  the  quantity  of  mercury  employed,  he  obtained  such  amalgams  as  Ag  ^Hg'",  Ag  Ilg", 

Ao-  TTrr'      Act  TTtr* 
Ag  "g  »  Ag  Ilg  . 

Beyond  those  there  are  many  experiments  which  appear  to  prove  that  alloys  are  true 
chemical  compounds ;  but,  at  the  same  time,  it  is  highly  probable  that  the  true  chemical 
alloy  is  very  often  dissolved  (mechanically  disseminated)  in  that  metal  which  is  l^firgely  in 
excess. 

Some  years  since,  the  editor  carried  out  an  extensive  series  of  experiments  in  the  labo- 
ratory of  the  Museum  of  Practical  Geology,  with  the  view  of  obtaining  a  good  alloy  for 
soldiers'  medals,  and  the  results  confirmed  his  views  respecting  the  laws  of  definite,  propor- 
tional combination  among  the  metals.  Many  of  those  alloys  were  struck  at  the  Mint,  and 
yielded  beautiful  impressions ;  but  there  were  many  objection^  urged  against  the  use  of  any 
alloy  for  a  medal  of  honor. 

The  alloys  of  the  following  metals  have  been  examined  by  Crookewitt,  and  he  has  given 
their  specific  gravities  as  in  the  following  table  ;  the  specific  gravity  of  the  unalloyed  metals 
being — 

Copper   -         -         -     S-TOi     I     Zinc        -         -         -     6-860 
Tin  -         -         -     7-305  Load       -         -         -  11-354 


That  of  the  alloys 

was — 

Cu^  Sn^ 

- 

7-652 

Cu   Pb 

-       10-375 

Cii  Sn 

. 

8-072 

Sn    Zn^ 

7-096 

Cu=  Sn 

. 

8-512 

Sn   Zn 

7-115 

Cu=  Zn* 

. 

7-939 

Sn'  Zn 

7-235 

Cu^*  Zn^ 

. 

8-224 

Sn   Pb^        - 

9-965 

Cu=Zn 

. 

8-392 

Sn   Pb 

9-394 

Cu-  Pb' 

- 

10-753 

Sn=  Pb 

9-025 

There  are  many  points  of  great  physical  as  well  as  chemical  interest  in  connection  with 
alloys,  which  rctjuire  a  closer  study  than  they  have  yet  received.  There  are  some  striking 
facts,  brought  forward  by  M.  Wcrthcim,  deduced  from  experiments  carried  on  upon  fifty- 
four  binary  alloys  and  nine  ternary  alloys  of  simple  and  known  composition,  which  will  be 
found  in  the  "  Joui-nal  of  the  French  Listitute,"  to  which  we  would  refer  the  reader. 


On  the  Meltinrj  Point  of  Certain  Alloys 
Centigrade 


Ccntifrrndfl 

Therinoinctcr. 

Tin,  2  atoms  ;  lead,  1  atom    -     196" 

"      1     "  "      1     "        .     241° 

"       1      "  "      3     «        .     289° 

"      2  vols. ;      "      1  vol.      -     194° 


In  these  experiments  of  M.  KniilTcr,  the  temperatures  were  determined  with  thermom- 


♦. 

Thermometer. 

Lead 

- 

. 

. 

334° 

Tin 

- 

- 

- 

. 

230° 

Tin, 

5 

atoms  ; 

lead, 

1 

atom 

- 

194° 

(( 

4 

" 

" 

1 

u 

- 

189° 

" 

3 

i( 

11 

1 

u 

- 

186° 

60  ALLOY. 

cters  of  great  delicacy,  and  the  weighings  were  carefully  carried  out. — Ann.  de  Chimu\  xl. 
285-3U2  ;  Breivslcr's  Edin.  Jour.  Sci.  i.  N.S.  p.  299. 

It  may  prove  convenient  to  give  a  general  statement  of  the  more  striking  peculiarities 
of  the  important  alloys.  More  detailed  information  will  be  found  under  the  heads  of  the 
respective  metals. 

Gold  and  Silter  Alloys. — The  British  standard  for  gold  coin  is  22  parts  pure  gold 
and  2  parts  alloy  ;  and  for  silver,  '222  parts  pure  silver  to  18  parts  of  alloy. 

The  alloy  for  the  gold  is  an  indefinite  proportion  of  silver  and  copper :  some  coin  has  a 
dark  red  color,  from  the  alloy  being  chietiy  copper  ;  the  lighter  the  color  a  larger  proportion 
of  silver  is  indicated,  sometimes  even  (when  no  copper  is  present)  it  approaches  to  a  greenish 
tinge,  but  the  proportion  of  pure  gold  is  the  same  in  either  case. 

The  alloy  for  silver  coinage  is  always  copper ;  and  a  very  pure  quality  of  this  metal  is 
used  for  alloying,  both  for  the  gold  and  silver  coinage,  as  almost  any  other  metal  being 
present,  even  in  very  small  quantities,  would  make  the  metals  unfit  for  coinage,  from  ren- 
dering the  gold,  silver,  and  copper  brittle,  or  not  sufficiently  malleable. 

Tiie  standard  for  plate  (silver)  is  the  same  as  the  coin,  and  requires  the  same  quan- 
tity of  copper,  and  carefully  melting  with  two  or  three  bits  of  charcoal  on  the  surface 
wliile  iu  fusion,  to  prevent  the  oxidation  of  the  copper  by  heat  and  exposure  to  the  atmos- 
phere. 

The  gold  standard  for  plate  and  jewellery  varies,  by  a  late  act  of  Parliament,  from  the 
22  carats  pure,  to  18,  12,  and  9:  the  alloys  are  gold  and  silver,  in  various  proportions, 
according  to  the  taste  of  the  workmen  ;  the  color  of  the  articles  manufactured  depending,  as 
with  the  coin,  on  the  proportions ;  if  no  copper  is  used  in  qualities  under  22  carats  fine 
gold,  the  color  varies  from  a  soft  green  to  a  greenish  white,  but  a  proportion  of  copper  may 
be  used  so  as  to  bring  the  color  to  nearly  that  of  22  fine,  1  silver,  and  1  copper. 

Wire  of  either  gold  or  silver  may  be  drawn  of  any  quality,  but  the  ordinary  wire,  for 
fine  purposes,  such  as  lace,  contains  from  5  to  9  pennyweights  of  copper  in  the  pound  of  240 
pennyweights,  to  render  it  not  so  soft  as  it  would  be  with  pure  silver. 

Gold,  silver,  and  copper,  may  be  mixed  in  any  proportions  without  injury  to  the  ductil- 
ity, but  j)o  reliable  scale  of  tenacity  appears  to  have  been  constructed,  although  gold  and 
silver  in  almost  any  proportions  may  be  drawn  to  the  very  finest  wire. 

The  alloys  of  silver  and  palladium  may  be  made  in  any  proportions  ;  it  has  been  found 
that  even  3  per  cent,  of  palladium  prevents  silver  tarnishing  so  soon  as  without  it ;  10  per 
cent,  very  considerably  protects  the  silver,  and  30  per  cent,  of  palladium  will  prevent  the 
silver  being  affected  by  fumes  of  sulphui'ctted  hydrogen  unless  very  long  exposed  :  the  latter 
alloy  has  been  found  useful  ft>r  dental  purposes,  and  the  alloy  with  less  proportions — say  10 
to  15  per  cent. — has  been  used  for  graduated  scales  of  mathematical  instruments. 

The  alloy  of  platinum  and  silver  is  made  for  the  same  purposes  as  those  of  palladium, 
and,  by  proper  care  in  fusion,  are  nearly  equally  useful,  but  the  platinum  does  not  seem  to 
so  perfectly  combine  with  the  silver  as  the  palladium.  Any  proportion  of  palladium  with 
gold  injures  the  color,  and  even  1  per  cent,  may  be  detected  by  sight,  and  5  per  cent,  ren- 
ders it  a  silver  color,  while  about  10  per  cent,  destroys  it ;  but  the  ductility  of  the  alloy  is 
not  much  injured. 

Gold  leaf  for  gilding  contains  from  3  to  12  grains  of  alloy  to  the  ounce.  Sixteen- 
carat  gold,  which  is  j  fine  gold  and  ^  alloy,  the  alloy  being  nearly  always  equal  portions  of 
silver  and  copper,  is  not  in  the  slightest  degree  injurious  for  dentists'  purposes. 

Antimony  in  the  proportion  of  -frVg  quite  destroys  the  ductility  of  gold. 

Gold  and  platinum  alloy  forms  a  somewhat  clastic  metal.  Ilermstadt's  imitation  of 
gold  consists  of  Ifi  parts  of  platinum,  7  parts  of  copper,  and  1  of  zinc,  put  in  a  crucible, 
covered  with  charcoal  powder,  and  melted  into  a  mass. — P.  J. 

Dentists'  amalgam  is  prepared  by  rubbing  together,  in  a  mortar,  or  even  in  the  hollow 
of  the  hand,  finely  divided  silver  and  mercury,  and  then  pressing  out  all  the  uncombincd 
mercury.  This  alloy,  when  put  into  the  hollow  of  a  decayed  tooth,  veny  soon  becomes 
exceedingly  hard.  Some  dentists  add  a  little  copper,  or  gold,  or  platinum  leaf,  under  the 
impression  that  the  amalgam  becomes  harder. 

Copper  Alloys. — Copper  alloyed  with  zinc  forms  Brass,  and  with  tin,  we  have 
Bronze.  (See  those  articles.)  The  alloys  of  the  ancients  were  usually  cither  brasses  or 
bronzes.  The  following  analyses  of  ancient  coins,  (Sec,  by  Mr  John  Arthur  Phillips,  are  of 
great  value. 

It  is  not  a  little  curious  to  find  that  some  of  the  coins  of  high  antiquity  contain  zinc, 
which  does  not  appear  to  have  been  known  as  a  metal  before  1280  a. n.,  when  Albertus 
Magnus  speaks  of  zinc  as  a  soni-ntctal,  and  calls  the  alloy  of  copper  and  zinc  f/olden  inarcn- 
si!r  :  or  rather,  perhaps,  he  means  to  apply  that  name  to  zinc,  from  its  power  of  imparting  a 
golden  color  to  copper.  The  probability  is  that  calamine  was  known  from  the  earliest  times 
as  a  peculiar  earth,  althougli  it  was  not  thought  to  be  an  ore  of  zinc  or  of  any  other  metal. 
— See  Watsoii's  Chemical  A'ssays. 


ALLOY. 


61 


Date. 

^ 

.J 

-• 

1 

.S 

>3 

§ 

.s 

N 

in 

a. 

is 

1 

D.C. 

A.D. 

Mi          .          -          .         - 

5U0 



69-69 

7-16 

21-82 

•47 





trace    trace 

■57 

StJiuis    -        -        •        - 

5(J0 



62.04 

7-66 

29.32 

•18 



— 

trace 

■19 

■23 

Quadrans       .        .        - 
Hiero  I.         -        ■        " 

500 



72  22 

7-17 

19-56 

•40 



— 

trace 

•20 

•23 

470 



9415 

5-49 

— 

•32 

Alexander  the  Great    - 

335 



86-77 

12-99 

— 

— 



— 

•06 

Philippus  III. 
Philippus  V.         -        - 
Copper  coin  of  Athens 
Egyptian,  Ptolemy  IX. 

323 



90  27 

9-43 

200 



8515 

11-12 

2-85 

•42 



— 

trace 

? 



88-34 

9-95 

•63 

•26 



— 

— 

trace 

trace 

70 



84-21 

15-64 

— 

trace 



— 

trace 

— 

trace 

Pompey,  First  Brass    - 

53 



74-17 

8-47 

16-15 

■29 

Coin  of  the  Atilia  Family 

45 



63-69 

4-86 

25-43 

■11 



— 

— 

trace 

trace 

Julius  and  Augustus    - 

•42 



79-13 

8-00 

12-81 

trace 



— 

trace 

Augustus  and  Agrippa 

30 

— 

78-45 

12-96 

8-62 

trace 

— 

— 

trace 

Large  Bra^^s  of  the  Cas-  ) 
sia  Family          -           | 

20 

_ 

82-26 





■35 

17-31 

_ 

trace 

Sword-blade 





89-69 

9-58 

— 

•33 

— 

— 

trace 

Broken  sword-blade     - 





85-62 

10-02 

— 

•44 

Fragment  of  sword-blade 





91-79 

8-17 

— 

trace 

— 

— 

trace 

Broken  spear-head 



— 

99-71 

— 

— 

— 

— 

— 

•23 

Celt       .... 





90-68 

7-43 

1-28 

trace 

— 

— 

trace 

Celt       .        -        -        - 





90-18 

9-81 

— 

trace 

Celt        ...        - 





89-33 

9-19 

— 

■33 

— 

— 

■24 

Celt       -        -        -        - 





83-61 

10-79 

3-20 

■58 

— 

— 

— 

trace 

■34 

Large  Brass  of  Nero 



60 

81-07 

1-05 

— 

— 

17-81 

Titus     ...        - 



79 

83-04 

— 

— 

■50 

15-84 

Hadrian         ... 



120 

85-67 

1-14 

1-73 

■74 

10.85 

Faustina,  Jun. 



165 

7914 

4  97 

9-18 

•23 

6-27 

Greek  Imperial  Samosata 



212 

70.91 

6-75 

21-96 

trace 

Victorinus,  8e3.  (No.  1) 

— 

262 

95-37 

•99 

trace 

trace 

— 

1-60 

Victorinus,  Sen.  (No.  2) 



262 

97-13 

■10 

trace 

101 

— 

1-76 

Tetrius,  Sen.  (No.  1)    - 

— 

267 

98-50 

■37 

trace 

■46 

— 

•76 

Tetrius,  Sen.  (No.  2)     - 



268 

98-00 

-51 

— 

■05 

— 

1-15 

Claudius  Gothicus(No.  1) 
Claudius  Gothicu3(No.  2) 

— 

|-263 

81-60 
84-70 

7-41 
3-01 

811 
2  67 

•31 

trace 

1-86 
7-93 

Tacitus  (No.  1)     - 



■275 

86-08 

3-63 

4-87 

— 

— 

4-42 

Tacitus  (No.  2)      - 

— 

91-46 

— 

— 

2^31 

— 

592 

Probus  (No.  1)      - 

— 

•275 

90-63 

2  00 

2. S3 

•61 

1-39 

2-24 

Probus  (No.  2)      - 



94-65 

•45 

■45 

•80 

— 

3-22 

^^ 

1 

Copper,  when  united  -with  half  its  weight  of  lead,  forms  an  inferior  alloy,  resembling 
gun-metal  in  color,  but  is  softer  and  cheaper.  This  alloy  is  called  pot-metal  and  cock-metal, 
because  it  is  used  for  large  measures  and  in  the  manufacture  of  tap-cocks  of  all  de- 
scriptions. 

Sometimes  a  small  quantity  of  zinc  is  added  to  pot-metal ;  but  when  this  is  considerable, 
the  copper  seizes  the  zinc  to  form  brass,  and  leaves  the  lead  at  liberty,  a  large  portion  of 
which  separates  on  cooling.  Zinc  and  lead  are  not  disposed  to  unite  ;  but  a  little  arsenic 
occasions  them  to  combine. 

Of  the  alloys  of  copper  and  lead,  Mr.  Holtzapffel  gives  the  following  description  : — 

Lead  Allots. — Two  ounces  lead  to  one  pound  copper  produce  a  red-colored  and  duc- 
tile alloy. 

Four  ounces  lead  to  one  pound  copper  give  an  alloy  less  red  and  ductile.  Neither  of 
these  is  so  much  used  as  the  following,  as  the  object  is  to  employ  as  much  lead  as  possible. 

Six  ounces  lead  to  one  pound  copper  is  the  ordinary  pot-metal,  called  dri/  pot-metal,  as 
this  quantity  of  lead  will  be  taken  up  without  separating  on  cooling ;  this  alloy  is  brittle 
when  warmed. 

Seven  ounces  lead  to  one  pound  copper  form  an  alloy  which  is  rather  short,  or  disposed 
to  break. 

Eight  ounces  lead  to  one  pound  copper  is  an  inferior  pot-metal,  called  wet  pot-metal,  as 
the  lead  partly  oozes  out  in  cooling,  especially  when  the  new  metals  are  mixed ;  it  is  there- 
fore always  usual  to  fill  the  crucible  in  part  with  old  metal,  and  to  add  new  for  the  remain- 
der. This  alloy  is  very  brittle  when  slightly  warmed."  More  lead  can  scarcely  be  u.sed,  as 
it  separates  on  cooling. 

Antimony  twenty  parts  and  lead  eighty  parts  form  the  printing-type  of  France ;  and 
li'ad  and  antimony  are  imitcd  in  various  proportions  to  form  the  type-metal  of  our  printers. 
_  See  Type. 

Mr.  James  Na.smyth,  in  a  letter  to  the  "  Athenjcum,"  (No.  IIYG,  p.  511.)  directed  atton- 
tiou  to  the  employment  of  lead,  and  its  fitness  as  a  substitute  for  all  works  of  art  hitherto 
executed  in  bronze  or  marble.  lie  says  the  addition  of  about  5  per  cent,  of  antimony  to 
the  lead  will  give  it,  not  only  great  hardness,  but  enhance  its  capability  to  run  into  the  most 
delicate  details  of  the  work. 

Baron  Wetterstedt's  patent  sheathing  for  ships  consists  of  lead,  with  2  to  8  per  cent,  of 
antimony;  al)out  3  per  cent,  is  the  usual  f|uaiitity.  The  alloy  is  rolled  out  into  sheets. — 
Holtzapffel.     We  are  not  aware  tliMt  this  alloy  has  ever  been  employed. 


62 


ALLOY. 


Emery  wheels  and  grinding  tools  for  the  lapidary  are  formed  of  an  alloy  of  antimony  and 
lead. 

Ort^an  pipes  are  sometimes  made  of  lead  and  tin,  the  latter  metal  being  employed  to 
harden  the  lead.  The  pipes,  however,  of  the  great  organ  in  the  Town  Hall  of  Birmingham 
are  principally  made  of  sheet  zinc. 

Lead  and  arsenic  form  shot-metal.  The  usual  proportions  are  said  to  bo  40  lbs.  of 
metallic  arsenic  to  one  ton  of  lead. 

Tabular  Stateincnt  of  the  Physical  Peculiarities  of  the  Principal  Alloys,  adopted,  with 
some  alterations,  from  the  ^^  Encyclopedic  Technologique.^' 


BRITTLE     METALS. 


Aksenic. 

With    Zinc,    rendering    it 
.  brittle. 

With  Iron  and  Steel,  hard- 
ending,  whitening,  and 
rendering  those  metals 
susceptible  of  a  fine  pol- 
ish :  much  used  for  steel 
chains  and  other  orna- 
ments. 

With  Gold,  a  gray  metal, 
very  brittle. 


With  Copper.  Composed 
of  62  parts  of  copper 
and  32  arsenic,  a  gray, 
brilliant,  brittle  metal. 
Increasing  the  quantity 
of  copper,  the  alloy  be- 
comes white  and  slightly 
ductile  :  used  in  the  man- 
ufacture of  buttons  un- 
der the  name  of  white 
copper,  or  Tombac. 

With  Silver.  23  of  silver 
and  14  of  arsenic  form 
a  grayish-white  brittle 
metal. 

With  Lead.  Arsenic  ren- 
ders lead  brittle.  The 
combination  is  very  inti- 
mate; not  decomposed 
by  heat. 


With  Tin.  Brittle,  gray, 
lamcUated ;  lees  fusible 
than  tin. 


With  Mercury. 
interest. 


Without 


Antimony. 
This  alloy  is  very  brittle. 


30  of  iron  and  70  of  anti- 
mony are  fusible ;  very 
hard,  and  white.  An 
alloy  of  two  of  iron  and 
one  of  antimony  is  very 
hard  and  brilliant. 


Forms  readily  a  pale-yellow 
alloy,  breaking  with  a 
fracture  like  porcelain. 

Alloys  readily :  the  alloys 
are  brittle.  Those  form- 
ed with  equal  parts  of 
the  two  metals  are  of  a 
fine  violet  color. 


These  have  a  strong  affini- 
ty ;  their  alloys  are  al- 
ways brittle. 


Antimony  gives  hardness 
to  lead.  24  parts  of  an- 
timony and  76  of  lead, 
corresponding  to  Pb"Sb, 
appear  the  point  of  satu- 
ration of  the  two  metals. 


The  alloys  of  antimony  and 
tin  are  very  wliite.  They 
become  brittle  when  the 
arsenic  is  in  large  quan- 
tity. 

A  gritty  white  alloy. 


Bismuth. 


Unknown. 


Doubtful. 


Similar  to  antimony,  of  a 
yellow-green  color. 


Pale-red  brittle  metal. 


Alloys    brittle 
lated. 


and  lamel- 


The.  alloys  of  bismuth  and 
lead  are  less  brittle  and 
more  ductile  than  those 
with  antimony;  but  the 
alloy  of  3  parts  of  lead 
and  2  of  bismuth  is 
harder  than  lead.  These 
alloys  are  very  fusible. 

Tin  and  bismuth  unite  in 
all  proportions  by  fusion. 
All  the  alloys  are  more 
fusible  than  tin. 


Mercury  dissolves  -a  large 
quantity  of  bismuth  with- 
out losing  its  fluidity; 
but  drops  of  the  alloy 
elongate,  and  form  a  tail. 


1 

ALLOY. 

63 

DUCTILE 

METALS. 

Iron. 

Gold. 

Copper. 

Silver. 

With    Zinc.       See 

A      greenish-yellow 

See  Brass. 

Silver  and  zinc  com- 

Galvanized Iron. 

alloy,    which    will 
take  a  fine  polish. 

bine  easily,  form- 
ing   a    somewhat 
brittle  allov. 

With  Iron  or  Steel. 

Gold  and  iron  alloy 

Iron  and  copper  do 

When    1    of    silver 

with     ease,      and 

not  form  true  al- 

and   500  of  steel 

form  yellowish  al- 

loys.  When  fused 

are  fused,  a  verv 

loys,    A'arving    in 

together,  the  iron, 

perfect   button  is 

color     with      the 

however,    retains 

formed.  —  Stodart 

proportions  of  the 

a  httle  copper. — 

and  Faraday. 

metals.     Three  or 

Several    methods 

four  parts  of  iron 

for    coating    iron 

united  with  one  of 

with    copper  and 

gold  is  verv  hard. 

brass  will   be  de- 

and    is    used     in 

scribed. 

the     manufacture 

of  cutting  instru- 

ments. 

With  Gold  - 

Copper  and  gold  al- 
loy in  all  propor- 
tions,  the  copper 
giving  hardness  to 
the  gold.   This  al- 
loy is  much  used 
in  coin  and  m  the 
metal  employed  in 
the     manufacture 
of  jewellery. 

Gold  and  silver  mix 
easily     together ; 
iSut  they    do   not 
appear  to  form  a 
true  combination. 
Jewellers       often 
employ   Vor   vert, 
which  is  compose (1 
of  70  parts  of  gold 
and   30   of  silver, 
which  corresponds 
very  nearly  to  the 
alloy      possessing 
the         maximum 
hardness. 

With  Copper 

Silver     and    copper 
alloy    in    all  pro- 
portions. Tliese  al- 
loys are  much  used 
in  the  arts.     The 
maximum      hard- 
ness appears  to  be 
produced       when 
the  alloy  contains 
a  fifth  of  copper. 

With    Lead,    does 

A  very  brittle  alloy. 

Do    not   appear    to 

Unite  in  all  propor- 

not     appear     to 

A  thousandth  pt. 

form  a  true  alloy. 

tions  ;  but  a  very 

form  any  alloy. 

oflead  is  sufficient 
to   alter  the  due- 
tiUty  of  gold. 

small   quantity  of 
lead   will    greatly 
diminish  the  duc- 
tility of  silver. 

With  Tin.     A  very 

The   alloys  of  gold 

Of  great  importance. 

Alloys   readily.      A 

little  iron  dimin- 

and tin  are  brit- 

See Bronze. 

very   small    quan- 

ishes the  mallea- 

tle ;  they  preserve. 

tity  of  tin  destroys 

bility  of  tin,  and 

however,        some 

the     ductility     ot 

gives  it  hardness. 

ductility  when  the 
proportion  of  tin 
does  not  exceed  J^. 

silver. 

With   Mercury. 

Mercury  has  a  most 

An  amalgam  which 

The  amalgamation  of 

Mercury   has   no 

powerful  action  on 

is  formed  with  dif- 

these   two  met.als 

action  on  iron. 

gold.     See  Amal- 

ficulty, and  with- 

is a  little  less  ener- 

gam. 

out  interest. 

getic  than  between 
mercury  and  gold. 
See      Amalgama- 
tion. 

U  ALLOY. 

In  addition  to  these,  the  alloys  of  iron  appear  of  sufficient  importance  to  require  some 
further  notit  e. 

Iron  and  Manganese. — Mr.  Mushet  concludes,  from  his  experiments,  that  the  maximum 
combination  of  manganese  and  iron  is  40  of  the  former  to  100  of  the  latter.  The  alloy 
71'4  of  tin  and  28-6  of  manganese  is  inditferent  to  the  magnet. 

Iron  and  Silver  ;  Steel  and  Silver. — Various  experiments  have  been  made  upon  alloys 
of  iron  and  steel  with  other  pietals.  The  only  alloys  to  which  sufficient  importance  has  been 
given  are  those  of  iron  and  silver  and  steel  and  silver.  M.  Guytou  states,  in  the  "  Annales 
de  Chimie,"  that  he  found  iron  to  alloy  with  silver  in  greater  quantity  than  the  silver  with 
the  iron.  "  Iron  can,"  he  says,  "  therefore  no  longer  be  said  to  refuse  to  mix  with  silver ; 
it  must,  on  the  contrary,  be  acknowledged  that  those  two  metals,  brought  into  perfect 
fusion,  contract  an  actual  chemical  union  ;  that  whilst  cooling,  the  heaviest  metal  separa/cs 
for  the  (jreatest  part ;  that,  notwithstanding  each  of  the  two  metals  retains  a  portion  of  the 
other,  as  is  the  case  in  every  liquidation,  the  part  that  remains  is  not  simply  mixed  or  inter- 
laid, but  chemically  united ;  lastly,  the  alloy  in  these  proportions  possesses  peculiar 
jjroperties,  particularly  a  degree  of  hardness  that  may  render  it  extremely  useful  for  various 
purposes." 

The  experiments  of  Faraday  and  Stodart  on  the  alloys  of  iron  and  steel  are  of  great 
value ;  the  most  interesting  being  the  alloy  with  silver.  The  words  of  these  experimen- 
talists are  quoted : — 

"  In  making  the  silver  alloys,  the  proportion  first  tried  was  1  silver  to  160  steel ;  the  re- 
sulting buttons  were  uniformly  steel  and  silver  in  fibres,  the  silver  being  likewise  given  out 
in  globules  during  solidifying,  and  adhering  to  the  surface  of  the  fused  buttons ;  some  of 
these,  when  forged,  gave  out  more  globules  of  silver.  In  this  state  of  mechanical  mixture 
the  little  bars,  when  exposed  to  a  damp  atmosphere,  evidently  produced  voltaic  action ;  and 
to  this  we  are  disposed  to  attribute  the  rapid  destruction  of  the  metal  by  oxidation,  no  such 
destructive  action  taking  place  when  the  two  metals  are  chemically  combined.  These 
results  indicated  the  necessity  of  diminishing  the  quantity  of  silver,  and  1  silver  to  200  steel 
was  tried.  Here,  again,  were  fibres  and  globules  in  abundance  ;  with  1  to  300  the  fibres 
diminished,  but  still  were  present ;  they  were  detected  even  when  1  to  400  was  used.  The 
successful  experiment  remains  to  be  named.  When  1  of  silver  to  500  steel  were  properly 
fused,  a  very  perfect  button  was  produced  ;  no  silver  appeared  on  its  surface  ;  when  forged 
and  dissected  by  an  acid,  no  fibres  were  seen,  although  examined  by  a  high  magnifying 
power.  The  specimen  forged  remarkably  well,  although  very  hard  ;  it  had  in  every  respect 
the  most  favorable  appearance.  By  a  delicate  test  every  part  of  the  bar  gave  silver.  This 
alloy  is  decidedly  superior  to  the  "very  best  steel;  and  this  excellence  is  unquestionably 
owing  to  a  combination  with  It  minute  quantity  of  silver.  It  has  been  repeatedly  made,  and 
always  with  equal  success.  Various  cutting  tools  have  been  made  from  it  of  the  best  qual- 
ity. This  alloy  is,  perhaps,  only  inferior  to  that  of  steel  and  rhodium,  and  it  may  be 
procured  at  small  expense  ;  the  value  of  silver,  where  the  proportion  is  so  small,  is  not  worth 
naming  ;  it  will  probably  be  applied  to  many  important  purposes  in  the  arts." 

Messrs.  Faraday  and  Stodart  show  from  their  researches  that  not  only  silver,  but  plati- 
num, rhodium,  gold,  nickel,  copper,  and  even  tin,  have  an  affinity  for  steel  sufficiently 
strong  to  make  them  combine  chemically. 

Iron  and  Nickel  unite  in  all  proportions,  producing  soft  and  tenacious  alloys.  Some 
few  years  since,  Mr.  Nasmyth  drew  attention  to  the  combination  of  silicon  with  steel.  Fresh 
interest  has  been  excited  in  this  direction  by  the  investigations  of  a  French  chemist,  M,  St. 
Claire  Deville,  who  has  examined  many  of  the  alloys  of  silicon. 

Silicon  and  Iron  combine  to  form  an  alloy  which  is  a  sort  of  fusible  steel  in  which  car- 
bon is  replaced  by  silicon.  The  siliciurets  are  all  of  them  quite  homogeneous,  and  are  not 
capable  of  being  separated  by  liquidation. 

Copper  and  Silicon  unite  in  various  proportions,  according  to  the  same  chemist.  A 
very  hard,  brittle,  and  white  alloy,  containing  12  per  cent,  of  silicon,  is  obtained  by  melting 
together  three  parts  silico-fluoride  of  potassium,  one  part  sodium,  and  one  part  of  copper, 
at  such  a  temperature  that  the  fused  mass  remains  covered  with  a  very  liquid  scoria.  The 
copper  takes  up  the  whole  of  the  silicon,  and  remains  as  a  white  substance  less  fusible  than 
silicon,  which  may  serve  as  a  base  for  other  alloys.  An  alloy  with  5  per  cent,  silicon  has  a 
beautiful  bronze  color,  and  will  probal)ly  receive  important  applications. 

Mr.  Oxland  and  Mr.  Truran  have  given,  in  "  Metals  and  their  Alloys,"  the  following  use- 
ful taVjular  view  of  the  composition  of  the  alloys  of  copper. 

The  principal  alloys  of  copper  with  other  metals  are  as  follows  : — 


ALOE. 


65 


Copper. 

Zinc. 

Tin. 

Nickel. 

Antimony. 

Lead. 

Antique  bronze  sword 

87-000 

.     . 

13-000 

1        "         springs 

97-000 

-     - 

3-000 

'  Bronze  for  statues 

91-400 

5-530 

1-700 

-     • 

- 

1-370 

"       for  medals 

90-000 

. 

10-000 

"       for  cannon 

90-000 

- 

10-000 

"       for  cymbals 

78-000 

-     - 

22-000 

"       for  gilding 

82-257 

17-481 

0-238 

.     . 

- 

0-024 

'»                 " 

80-000 

16-500 

2-500 

.     . 

. 

1-000 

Speculum  metal 

66-000 

-     . 

33-000 

Brass  for  sbeet     - 

84-700 

15-300 

Gilding  metal       -         -         - 

73-730 

27.270 

Pinchbeck 

80-200 

20-000 

Prince's  metal      .         .         - 

75-000 

25-000 

"           "... 

50-000 

50-000 

Dutch  metal         ... 

84-700 

15-300 

English  wire 

70-290 

29-260 

0-17 

.    . 

. 

0-28 

Mosaic  gold 

66-000 

33-000 

Gun  metal  for  bearings,  stocks,  &c. 

90-300 

9-670 

0-03 

Muntz's  metal 

60-000 

40-000 

Good  yellow  brass 

66-000 

33-000 

Babbitt's  metal  for  bushing 

8-300 

-     - 

83-00 

.     . 

8-3 

Bell  metal  for  large  bells 

80-000 

-     . 

20-00 

Britannia  metal 

1-000 

2-00 

81-00 

.     . 

16-00 

Nickel  silver,  English 

60-000 

17-8 

.     . 

22-2 

"          "       Parisian 

50-000 

13-6 

.     . 

19-3 

German  silver 

50-000 

25-0 

-     - 

25-0 

ALLOY,  NATIVE.  Osmium  and  Iridium,  in  the  proportions  of  72-9  of  the  former  and 
24-5  of  the  latter.     See  Osmium,  Iridium. 

ALLSPICE.  Pimento,  or  Jamaica  pepper,  so  called  because  its  flavor  is  thought  to 
comprehend  the  flavor  of  cinnamon,  cloves,  and  nutmegs.  The  tree  producing  this  spice 
{Eugenia  phnenla)  is  cultivated  in  Jamaica  iu  what  are  called  Pimento  walks.  It  is  im- 
ported in  bags,  almost  entirely  from  Jamaica. 

ALMOND.  (Aiiiande,  Fr.  ;  3Iandclus,  Germ.  ;  Amygdal  communis.)  De  Candolle 
admits  five  varieties  of  this  species.  A.  amara,  bitter  almond  ;  A.  dulcis,  sweet  almond  ; 
A.  frariilis,  tender-shelled  almond  ;  A.  macrocarpa,  large-fruited  almond  ;  A.  peisicoides, 
peach  almond. 

Three  varieties  are  known  in  commerce : 

1.  Jordan  Almonds,  which  are  the  finest,  come  from  Malaga.  Of  these  there  are  two 
kinds :  the  one  above  an  inch  in  length,  flat,  with  a  clear  brown  cuticle,  sweet,  mucilagi- 
nous, and  rather  tough  ;  the  other  more  plump  and  pointed  at  one  end,  brittle,  but  equally 
sweet  with  the  former. 

2.  Valentia  Almonds  are  about  three-eighths  of  an  inch  broad,  not  quite  an  inch  long,  round 
at  one  end,  and  obtusely  pointed  at  the  other,  flat,  of  a  dingy  brown  color,  and  dusty  cuticle. 

3.  Barbary  and  Italian  almonds  resemble  the  latter,  but  arc  generally  smaller  and  loss 
flattened. — Brande,  Dictionary  of  Pharmacy. 

ALMOND  OIL.  A  bland  fixed  oil,  obtained  by  expression  from  cither  bitter  or  sweet 
almonds ;  usually  from  the  former,  on  account  of  their  cheapness  as  well  as  the  gi-eater 
value  of  the  residual  cake.  The  average  produce  is  from  48  to  52  lbs.  from  1  cwt.  of 
almonds. — Pereira. 

ALMOND  POWDER  {farina  amygdalce)  is  the  ground  almond  cake,  and  is  employed 
as  a  cake  for  washing  the  hands,  and  as  a  lute. 

ALOE.  {Aloes,  Fr.  ;  Glauindes  aloe,  Germ.)  In  botany  a  genus  of  the  class  Jlexan- 
dria  monoffynia.     There  are  many  species,  all  natives  of  warm  climates. 

In  Africa  the  leaves  of  the  Guinea  aloe  are  made  into  durable  ropes.  Of  one  species  are 
made  lines,  bow-strings,  stockings,  and  hammocks ;  the  leaves  of  another  species  are  used 
to  hold  rain  water. 

A  patent  has  been  taken  (January  27th,  1847)  for  certain  applications  of  aloes  to  dyeing. 
Although  it  has  not  been  employed,  the  coloring  matter  so  obtained  promising  to  be  very 
permanent  and  intense,  it  is  thought  advisable  to  describe  the  process  by  which  it  is  pro- 
posed to  prepare  the  dye.     It  is  as  follows  : 

Into  a  boiler  or  vessel  capable  of  iiolding  about  100  gallons,  the  patentee  puts  10  gallons 
of  water,  and  132  lbs.  of  aloes,  and  heats  the  same  until  the  aloes  are  dissolved  ;  he  then 
adds  80  lbs.  of  nitric  or  nitrous  acid  in  small  proportions  at  a  time,  to  prevent  the  discn- 
VoL.  III.— 5 


66  ALPACA. 

gagement  of  such  a  quantity  of  nitrous  gas  as  would  throw  part  of  the  contents  out  of  the 
boiler.  When  the  whole  of  the  acid  has  been  introduced,  and  the  disengagement  of  gas  has 
ceased,  10  lbs.  of  liquid  caustic  soda,  or  potash  of  commerce,  of  about  30^,  are  added  to 
neutralize  any  undecomposed  acid  remaining  in  the  mixture,  and  to  facilitate  the  use  of  the 
mixture  in  dyeing  and  printing.  If  the  coloring  matter  is  required  to  be  in  a  dry  state,  the 
mixture  may  be  incorporated  with  100  lbs.  of  china  clay  and  dried  in  stones,  or  by  means 
of  a  current  of  air.  The  coloring  matter  is  used  in  dyeing  by  dissolving  a  sufficient  quan- 
tity in  water,  according  to  the  shade  required,  and  adding  as  much  hydrochloric  acid  or  tar- 
tar of  commerce  as  will  neutralize  the  alkali  contained  in  the  mixture,  and  leave  the  dye 
bath  slightly  acidulated.  The  articles  to  be  dyed  arc  introduced  into  the  bath,  which  is 
kept  boiling  until  the  desired  shade  is  obtained. 

When  the  coloring  matter  is  to  be  used  in  printing,  a  sufficient  quantity  is  to  be  dis- 
solved in  water,  according  to  the  shade  req-uired  to  be  produced ;  this  solution  is  to  be 
thickened  with  gum,  or  other  common  thickening  agent,  and  hydrochloric  acid,  or  tartar  of 
commerce,  or  any  other  suitable  supersalt,  is  to  be  added  thereto.  After  the  fabrics  have 
been  printed  with  the  coloring  matter,  they  should  be  subjected  to  the  ordinary  process  of 
steaming,  to  fix  the  color. — Napier. 

Aloetic  acid,  on  which  the  coloring  matter  of  the  aloes  depends,  has  been  examined  by 
Schunck  and  Mulder.  Aloetic  acid  is  deposited,  from  nitric  acid  which  has  been  heated  with 
aloes,  as  a  yellow  powder ;  it  dissolves  in  ammonia  with  a  violet  color  ;  when  treated  with 
protochloride  of  tin,  it  forms  a  dark-violet  heavy  powder ;  and  this,  again,  when  treated 
with  potash,  evolves  ammonia,  and  assumes  a  violet-blue  color.  The  solution  of  aloetic  acid 
in  ammonia  is  violet. 

ALPACA.  {Alpaga,  Fr.)  An  am'mal  of  Peru,  of  the  Llama  species  ;  also  the  name 
given  to  a  woollen  fabric  woven  from  the  wool  of  this  animal. 

ALUM.  {Ahm,  Fr.  ;  Alaun,  Germ.)  A  saline  body  or  salt,  consisting  of  alumina,  or 
the  peculiar  earth  of  clay,  united  with  sulphuric  acid,  and  these  again  united  with  sulphate 
of  potash  or  ammonia.  In  other  words,  it  is  a  double  salt,  consisting  of  sulphate  of  alumina 
and  sulphate  of  potash,  or  sulphate  of  alumina  and  sulphate  of  ammonia.  The  common 
alum  crystallizes  in  octahedrons,  but  there  is  a  kind  which  takes  the  form  of  cubes.  It  has 
a  sour  or  rather  subacid  taste,  and  is  peculiarly  astringent.  It  reddens  the  blue  color  of 
litmus  or  red  cabbage,  and  acts  like  an  acid  on  many  substances.  Other  alkalies  may  take 
the  place  of  the  ammonia  or  potash,  and  other  metals  that  of  the  aluminium. 

The  composition  of  alum  is  expressed  by  chemists  in  the  following  manner  :  APO'  8S0' 
KOSO'  24HO.  This  peculiar  combination  is  that  of  the  original  substance  as  far  as  it 
appeared  to  the  chemists  of  last  century,  and  the  form  is  now  held  as  a  type,  after  which 
many  other  alums  are  composed.  Ammonia-alum  was  occasionally  made,  even  as  early  as 
Agricola's  time,  16th  century.  Its  composition  is  APO'  3S0'  NH<  OSO'  -f  24HO.  The 
same  thing  occurs  with  soda ;  soda  alum  is  APO'  SSO'  NaOSO'  -|-  24HO.  Every  salt  hav- 
ing this  form  is  called  an  alum.  Sometimes,  instead  of  the  alkali  being  changed,  the  earth 
is  changed.  Thus  we  have  chrome-alum,  Cr^O^SSO'  KOSO'  +  24HO  ;  or  we  have  an  iron- 
alum,  Fe^  0^  3S0^  KOSO=  -\-  24HO.  These  may  be  varied  to  a  great  extent,  but  all  have  a 
characteristic  of  alum.  The  twenty-four  atoms  of  water  are  one  of  the  peculiar  characteristics. 

Composition  of  pure  Potash  Alum. 

Per  Cent.  Per  Cent. 

Potash  -         -     9-89  or  1  atom  Al  \        /c  i  i    *.      e      .    i       lo  o.->  i  „t„~    nh 

.,      .                 T,^„,    <<    1      u      rn  /        I  Sulphate  of  potash  -  1S*32  or  1  atom    27 

Alumina         -  10"94         1             52  (         j  o  i   i    *       r    i       ■        o/.  .n  u    ■>      u      -nrr. 

or -^  Su  phate  of  alumma  36-21  "    1            l72 


(  Sulphat 
•]  Sulphat 
(  Water 


Sulphuric  acid  33-68    "   4     "    160  f  "' ]  ^^^'-^^^"^  ^'r'"'^"^^^    .   {     ..      216 
Water-         -45-49    "24     "    216)        I  ^^^ter  40 -ib        i  ^io 

Its  specific  gravity  is  1-724. 

100  parts  of  water  dissolve,  at  32  degrees  Fahrenheit,  3-29  alum. 
"  "  "  50         "  "  9-52      " 

"  "  "  86  "  "        2201      " 

n  u  ((  J22         "  "        30-92      " 

U  i<  «  jgg  «  1.  (jQ.QY  U 

"  "  "  212         "  "      857-48      " 

These  Tables  of  Poggiale  should  be  re-examined,  and  gradations  made  more  useful 
for  this  country. 

Solubility. — 1  part  of  crystallized  potash  alum  is  soluble — 

At   54   degrees  Fahrenheit  in  13-3  water. 
"    70         "  "  8-2      " 

«i    77         »i  «  4.5      u 

"  100  "  "  2-2  " 

"  122  '•'  "  2*0  " 

"  145  "  "  0-4  " 

"  167  "  "  0-1  " 

"  189-5  "  "  0-06  " 


ALUM.  67 

A  solution  saturated  at  46°  is  1-045  specific  gravity.  This  diiference  in  the  rate  of  solu- 
bility in  hot  and  cold  water  renders  it  easily  separated  from  many  other  salts.  The  crystals 
are  permanent  in  the  air,  or  nearly  so,  unless  the  air  be  very  dry ;  if  kept  at  180°  they  lose 
18  atoms  of  water,  but  alum  deprived  of  its  water  and  exposed  to  the  air  of  summer  took 
up  18  atoms  in  47  days.  It  melts  at  a  low  temperature  in  its  water  of  crystallization.  At 
356'  it  loses  43*5  per  cent,  of  water,  or  23  atoms;  the  last  atom  is  only  lost  when  ap- 
proaching red  heat.  At  a  red  heat  the  sulphate  of  alumina  loses  its  acid,  and  the  alumina 
seems  then  able  to  remove  some  acid  from  the  potash,  losing  it  again  by  heat.  Alum,  when 
heated  with  common  salt,  acts  like  sulphuric  acid,  and  gives  oft"  muriatic  acid ;  the  same 
with  chlorides  of  potassium  and  ammonium.  If  boiled  with  a  saturated  solution  of  chloride 
of  potassium,  hydrochloric  acid  is  formed  and  a  subsulphate  of  alumina  falls  down ;  this 
occurs  only  to  a  small  extent  with  chloride  of  sodium,  and  still  less  with  sal-ammoniac. 

Appli'calions  of  Alum. — Alum  is  an  a^ringent.  Its  immediate  effect  on  man  is  to 
corrugate  the  fibres  and  contract  the  small  vessels.  It  precipitates  albuminous  liquids  and 
combines  with  gelatine.  It  causes  dryness  of  the  mouth  and  throat,  and  checks  the  secre- 
tions of  the  alimenary  canal,  producing  constipation  ;  in  large  quantities,  nausea,  vomiting, 
puro-ing.  It  is  given  in  lead  coUc,  to  convert  the  lead  into  sulphate  of  lead,  and  used 
externally.  Its  principal  use  is  in  dyeing  ;  calico-printers  print  it  as  a  mordant,  the  cloth  is 
then  put  "into  the  dye,  and  the  printed  parts  absorb  the  color.  Paper-makers  use  it  in  their 
size  and  bookbinders  in  their  paste.  It  is  used  in  tanning  leather,  and  sometimes,  both  in 
Asia  and  Europe,  it  is  used  for  precipitating  rapidly  the  impurities  of  water.  This  is  a 
dangerous  process,  unless  there  be  a  great  amount  of  alkaline  salts,  such  as  carbonate  of 
lime  or  soda  to  neutralize  the  acid.  It  is  extensively  used  in  correcting  the  baking  qualities 
of  bad  flour,  for  which  the  experience  of  many  has  decided  that  it  is  a  valuable  remedy ; 
unfortunately,  it  is  also  used  to  make  excellent  flour  whiter,  when  there  is  no  need  of  its 
presence.  Liebig  says  that  lime  is  equally  good,  and  of  course  much  safer.  From  time 
immemorial  it  has  been  used  to  prevent  the  combustibility  of  wood  and  cloth. 

Alum  heated  with  charcoal  or  carbonaceous  substances  forms  Homberg's  phosphorus, 
which  inflames  spontaneously.  It  is  composed  of  alumina,  sulphide  of  potassium,  and 
charcoal. 

Burnt  Alum.,  or  dried  alum,  is  made  by  gently  heating  alum  till  the  water  is  driven  off. 
The  alum  first  melts  in  its  water  of  crystallization  and  is  then  dried.  It  has  a  stronger 
action  than  the  hydrated  crystals,  and  is  a  mild  escharotie.     It  reabsorbs  water. 

Ammonia-alum  readily  loses  all  its  ammonia  when  heated,  and  the  sulphuric  acid  may 
be  driven  off  the  remaining  sulphate  of  alumina,  so  that  the  pure  earth-alumina  will  remain. 

Neutral  Alum  is  a  name  sometimes  given  erroneously  to  alum  which  has  had  some  of  its 
acid  neutralized  by  an  alkali.  It  is,  in  fact,  a  basic  salt  of  alumina,  which  may  also  be  made 
by  dissolving  alumina  in  ordinary  alum.  It  deposits  a  basic  salt  more  readily  than  ordinary 
alum,  and  may  be  of  service  in  some  cases  of  printing.  Properly  speaking,  the  common  alum 
is  the  neutral  salt. 

Testing  of  Alum. — Alum  being  generally  in  large  crystals,  any  impurity  is  more  readily 
seen ;  this  is  said  to  be  the  reason  for  keeping  up  the  practice  of  making  this  substance 
instead  of  the  sulphate  of  alumina  alone,  which  is  less  bulky  and  fitted  for  nearly  every 
purpose  for  whj).-h  altnn  is  used.  But  probably  the  ancient  accidental  discovery  of  the  pot- 
ash form  has  determined  its  use  to  the  present  day.  Iron  is  readily  found  in  it,  by  adding 
to  a  dilute  solution  ferrocyanide  of  potassium  or  prussiate  of  potash,  which  throws  down 
Prussian  blue.  A  very  delicate  test  is  sulphuret  of  ammonium,  which  throws  down  both 
the  alumma  and  iron,  but  the  blacking  of  the  precipitate  depends  on  the  amount  of  iron. 
The  total  amount  of  iron  is  got  by  adding  pure  caustic  pot;ish  or  soda  till  the  solution  is 
strongly  alkaline,  washing  and  filtering  off  the  oxide.  To  look  for  lime,  precipitate  the 
alumina  and  iron  by  ammonia,  boil  and  filter,  the  lime  and  magnesia  are  in  the  solution, 
add  oxalate  of  ammonia  -,  add  tartaric  acid  to  keep  up  the  iron  and  alumina,  make  alkaline 
by  ammonia,  then  precipitate  the  lime  by  oxalate  of  ammonia,  filter,  and  precipitate  the 
magnesia  by  a  phosphate.  Silica  and  insoluble  basic  sulphates  arc  obtained  by  simply  dis- 
solving the  alum  in  water  and  filtering.  If  silica,  it  is  insoluble  in  acids ;  if  a  basic  sulphate, 
it  will  dissolve  in  sulphuric  acid,  and  the  addition  of  sulphate  of  potash  or  ammonia  will 
convert  it  into  potash  or  ammonia-alum. 

Its  formula,  according  Jo  Graham,  is  a  basic  alum,  HO  SO' +  3(A1'0'S0') -f  OHO. 
By  losing  alumina  it  becomes  the  neutral  salt. 

.  Sulphate  of  Alumina. — The  first  step  towards  the  production  of  alum  is  the  sulphate  of 
alumina.  This  is  found  in  various  proportions  in  alum  stone.  The  pure  mineral  has  the 
following  composition : — 

1  atom  of  alumina     -         -     15*42  per  cent, 
3  atoms  of  sulphuric  acid  -     85'99        " 
18  atoms  of  water      -        -     48-59        " 

100- 


68 


ALUM. 


There  are  many  analyses  of  natural  specimens  closely  approaching  this.  It  is  found  crys- 
tallized in  a  close  mass  of  fine,  white,  flexible  needles,  of  a  feather  or  hair  form,  and  has 
been,  like  a  few  other  substances,  called  hair-salt.  It  is  also  found  with  various  degrees  of 
impurity,  sometimes  with  a  smaller  amount  of  water.  Knapp  has  collected  the  following 
list  of  analyses : — 

Analyses  of  Natural  Sulphate  of  Alumina  or  Feather  Alum. 


The  manufacture  of  alum  involves  the  making  of  sulphate  of  alumina  in  the  first 
instance  in  all  cases  where  potash  is  not  present  in  the  ore  ;  for  this  reason  the  description 
of  both  is  included  in  one  article. 

Ores  or  Raw  Material. — The  chief  difficulty  in  manufacturing  alum  has  been  the  solu- 
tion of  the  alumina.  This  substance  is  generally  combined  with  silica  in  such  a  strong  cooj- 
binution,  that  even  powerful  acids  cannot  remove  it  without  assistance.  The  older  methods, 
however,  took  no  notice  of  these  difficulties,  and  obtained  the  alum  more  or  less  directly 
from  nature.  The  method  now  practised  at  the  Solfatara  di  Pozzuoli  and  the  island  Vul- 
cano  is  simply  to  take  the  efflorescence  and  the  earth  containing  it,  wash  it  with  water,  and 
concentrate.  But  it  very  seldom  contains  a  sufBcient  amount  of  potash  to  form  alum.  A 
salt  of  potash  is  then  added,  chiefly  a  carbonate.  To  transform  this  into  a  sulphate,  a  por- 
tion of  the  sulphate  of  alumina  is  decomposed.  The  use  of  a  carbonate  is  a  wasteful  method 
of  modern  times ;  the  ancients  would  have  felt  no  difficulty,  but  boiled  all  down,  and  so 
obtained  the  whole  alumina  there.  Their  product,  therefore,  would  have  been  basic  sul- 
phate of  alumina,  which  it  evidently  was  when  this  practice  was  resorted  to.  When  they 
merely  concentrated  and  then  crystallized,  they  got  pure  alum  ;  but  they  lost  a  great  deal 
of  their  alumina. 

At  Tolfa  the  alum  is  obtained  from  a  compact  crystalline  substance  called  alunite.  The 
analysis  of  Cordier  makes  it  a  combination  of  alum  with  alumina.  If  treated  with  water 
only,  it  will  not  give  out  alum  ;  but  if  moderately  calcined,  it  breaks  up,  gives  out  a  large 
amount  of  alum,  and  the  liquid  is  then  boiled  down  for  crystallization. 

Here  are  specimens  of  the  ore,  two  of  which  contain  a  considerable  amount  of  potash. 
As  there  is  seldom  enough  of  potash  found,  it  must  be  added  in  the  form  of  sulphate  of 
potash  or  chloride  of  potassium. 


Sulphuric  acid 

36-187 

34-6 

20-06 

Alumina 

35-105 

40-0 

S9-70 

Potash 

10-824 

15-8 

Lime   0-SO 

Water 

18-124 

10-6 

59-94 

100-240 


100-0 


120-00 


These  formations  of  alum  are  generally  found  where  sulphurous  gases  are  exhaled 
rock  is  gradually  decomposed. 


the 


ALUM. 


69 


It  is  not,  however,  found  so  rich  in  the  great  majority  of  cases. 
yses  of  some  alum  stones  : — 


The  following  are  anal- 


Klaproth. 

Klaproth. 

Descotil. 

Cordier. 

Tolfa 
Alum  Stone. 

Beregszaz 
Alam  Stone. 

Montlone. 

Mont  d'Or. 

Silica 

Alumina 

Sulphuric  acid       -        .        -        - 

Potash 

Water            ..... 
Oxide  of  iron 

56-5 

19-0 

16-5 

4-0 

3-0 

62-3 

17-5 

12-5 

1-0 

5-0 

40.0 
35-6 
13-8 
10-0 

28-4 

31-8 

27-0 

5-8 

3-7 

1-4 

When  there  is  no  silica,  but  only  sulphuric  acid,  alumina,  and  potash,  we  have  a  natural 
alum,  and  in  that  case  there  is  nothing  to  be  done  towards  the  manufacture.  But  it  rarely 
happens  that  the  constituents  exist  in  a  proportion  to  form  the  crystalline  salt.  There  may 
be  sulphate  of  alumina,  hydrate  of  alumina,  and  some  true  alum,  or  sulphate  of  alumina  and 
potash.  This  excess  of  hydrate  of  alumina  forms,  when  united  with  the  sulphate,  a  basic 
or  insoluble  sulphate  of  alumina,  and  nothing  but  the  sulphate  of  pota.sh  becomes  soluble. 
When  the  hydrate  is  heated,  the  water  escapes ;  the  sulphate  of  alumina  and  potash  are 
then  capable  of  being  washed  out  together,  and  alum  is  obtained.  At  Tolfa  it  is  obtained 
in  crystals,  covered  over  with  a  light  red  powder  of  peroxide  of  iron.  This  reddish  covering 
always  accompanies  the  Roman  or  partly  cubical  alum,  and  it  has  been  sometimes  added  in 
order  to  give  common  alum  the  appearance  of  the  Roman. 

As  the  principal  difficulty  in  the  manufacture  of  alum  is  the  solution  of  the  alumina,  it 
is  unfortunate  that  so  much  of  the  hydrate  is  destroyed,  as  in  the  process  mentioned,  when 
sulphuric  acid  would  readily  dissolve  it  and  greatly  increase  the  produce.  By  the  method 
described  to  us,  the  measure  of  alum  is  simply  the  amount  of  the  potash.  All  that  cannot 
find  potash  to  unite  with  is  lost. 

Occasionally  ammonia-alum  is  found  in  nature.  Analyses  have  been  made  of  specimens 
from  Tschermig,  in  Bohemia,  by  Stromeyer  : — 


Alumina 

. 

11-602 

Ammonia 

- 

3-721 

Magnesia 

. 

0-115 

Sulphuric  acid 

. 

36-065 

Water    - 

- 

48-390 

99-893 


Sulphate  of  alumina 
Sulphate  of  ammonia 
Sulphate  of  magnesia 
Water 


38-688 

12-478 

0-337 

48-390 

99-893 


Soda-alum  is  also  found  naturally. 

Alum  from  Peru,  by  T.  Thomson. 

Sulphate  of  soda 6-50 

Alumina 2255 

Sulphuric  acid 32-95 

Water 39-20 

101-20 

From  the  Andes. 

Sulphuric  acid 86-199 

Alumina  -         -         .         . 11 -511 

Soda 7-259 

Water 43-819 

Silica 0-180 

Lime 0-255 

Peroxide  of  iron 0*199 

Protoxide  of  iron  -         -         - 0-760 


100-162 

Messrs.  Richardson  and  Ronalds  have  given  some  very  minute  analyses  of  the  Whitby 
and  Campsie  shales. 


70 


ALUM. 


"Whitby. 


Top  Rock. 


Bottom 
Eock. 


Top  Eock. 


Campsie. 


Top  Eock. 


Bottom 
Eock. 


Sulphur 

Iron     - 

Sulphuret  of  iron 

Silica  - 

Protoxide  of  iron 

Alumina 

Lime   - 

Magnesia 

Oxide  of  manganese 

Sulphuric  acid 

Potash 

Soda    -         -         - 

Chlorine 

Carbon  and  loss  - 

Carbon 

Coal    - 

Loss    -        -        - 

Water 


4-20 

52-25 
8-49 

18-75 
1-25 
0-91 

traces 
1-37 
0-13 
0-20 

traces 


8-50 
51-16 

6-11 
18-30 

2-15 

0-90 
traces 

2-50 
traces 
traces 
traces 


4-97 
2-88 


8-29 


2-00 


95.40 


91-91 


22-36 
18-16 

15-40 

11-35 
1-40 
0-50 
0-15 

0-90 


23-44) 
15-04/ 

15-40 

11-64 

2-22 
0-32 


9-63 

0-47 
2-18 
18-91 
0-40 
2-17 
0-55 
0-05 
1-26 
0-21 


29-78 


28-80 
3-13 


8-51 
0-59 
8-54 


100-00 


99-99 


100-00 


As  the  Top  one  contains  a  larger  excess  of  iron  pyrites  than  the  Bottom,  they  are 
mixed  so  as  to  diffuse  the  sulphuric  acid  equally. 

Erdmann  has  thus  analyzed  his  German  specimens  : — 


Garnsdorff. 

Wezelstein. 

^Sulphuret  of  iron          .         -         .         . 

7-533 

10-166 

Silica 

0-060 

0-100 

Soluble  in  acid.     - 

Peroxide  of  iron 

Alumina       ...... 

0-966 
1-833 

2-466 
3-166 

Lime 

0-400 

1-000 

Magnesia 

trace 

1-022 

Silica    .---.-- 

50-066 

52-200 

Alumina 

8-900 

17-900 

Insoluble  in  acid.  -! 

Peroxide  of  iron 

Magnesia      .-.--. 

1-300 
1-000 

3-566 
1-133 

Lime 

trace 

trace 

Coal 

22-833 

0-805 

Water 

2-208 

5-080 

Other  shales  will  be  found  of  interest ;  the  following  are  by  G.  Kersten : — 


« 

Hermann- 

schachto. 

Gluckauf- 
gung. 

Elucher- 
scbachte. 

Curbonaoeous  matter 

Silica 

Peroxide  of  iron 

Alumina 

Magnesia 

Sulphur 

Oxide  of  manganese         ........ 

Sulphate  of  lime       ..-.•- 

41-10 
44-02 
6-23 
5-60 
0-32 
1-25 
0-12 
traces 

27-92 

51  32 

8-40 

7-62 

0-26 

2-89 

traces 

traces 

34-20 

50-21 

0-42 

5-21 

0-53 

1-72 

traces 

traces 

98-64 

98-41 

98-39 

ALUM.  n 

Shales  from  Freienwalde,  Shales  from  Puzberg^ 

by  Klaproth.  by  Bergeraann. 

Alumina     -  '       -         -         16-000 10-80 

Silica          -         -         -         40-00 45-30 

Magnesia    .         -         -  0-25 

Sulphur      -         -         -           2-85 3-94 

Carbon       -         -         -         19-65 5-95 

Protoxide  of  iron       -           6-40 5*50 

Oxide  of  manganese  -  0-60 

Sulphateof  protoxide  of  iron  1-80  -         -         -         -         -  5-'73 

"               "         alumina  1-20 

»               ".       lime        1-50 l-H 

"               "         potash    1-60  -----  1-75 

Chloride  of  potassium           0-50 0-35 

Sulphuric  acid       -         -  0'4'7 

Water           -         -         -       10-75 16-50 


101-20  99-70 

Here  the  sulphur  has  evidently  existed  in  combination  with  iron,  which  has  been  united 
to  oxygen  by  the  analysts.  The  amount  of  sulphate  shows  a  partial  disintegration  and 
other  changes. 

Lampadius  gives  another  with  much  more  sulphur  : — 

Alum  Shale  from  Siehda. 

Sulphate  of  alumina, 2-68 

Potash-alum, 0-47 

Sulphate  of  iron, 0-95 

Sulphate  of  lime, -  l-'rO 

Silica, .-  10-32 

Alumina,     -----------  9-21 

Magnesia, traces 

Oxide  of  iron, 2-30 

Oxide  of  manganese, --  0'31 

Sulphur, T-IS 

Water, 33-90 

Carbon, 31-03 

100-00 

When  alum  is  made  of  such  shale,  the  object  is  first  of  all  to  oxidize  the  sulphur,  form- 
ing sulphuric  acid.  This  acid  then  dissolves  the  alumina.  The  result  may  be  accomplished 
by  allowing  the  shale  to  disintegrate  spontaneously  in  the  air,  the  sulphur  oxidizing  and  dis- 
solving the  alumina.  But  in  general,  as  at  WhitVjy  and  Campsie,  combustion  must  be 
resorted  to.  This  can  be  accomplished  without  the  use  of  coal,  further  than  is  needful  sim- 
ply to  set  fire  to  that  portion  which  exists  in  the  shale  itself.  Indeed,  the  Campsie  one, 
having  more  coal  than  is  desirable  for  slow  combustion,  is  mixed  with  some  spent  material, 
in  order  to  diminish  the  force  of  the  heat. 

The  sulphur  is  united  with  the  iron,  forming  a  bisulphuret,  each  atom  of  which  must 
therefore  take  up  seven  atoms  of  oxygen,  FeS--f-70=reO  SO=-f-SO^  When  combustion 
takes  place,  the  sulphur  oxidizes ;  if  rapid  combustion  is  used,  then  sulphurous  acid  gas 
escapes ;  if  slow  combustion,  the  sulphurous  acid  penetrates  the  mass  slowly,  receives 
another  atom  of  oxygen,  unites  to  a  base,  and  a  sulphate  is  the  consequence.  Sulphate  of 
iron  is  formed  and  pure  sulphuric  acid.  In  the  process  it  is  probable  that  the  oxidation  is 
completed  by  means  of  the  iron.  Protoxide  of  iron  readily  becomes  peroxide ;  the  sul- 
phurous acid  readily  decomposes  peroxide,  forming  sulphupc  acid  and  protoxidoof  iron. 
Tills  protoxide  of  iron  is  again  converted  into  peroxide,  and  if  not  dissolved  is  rendered,  to 
a  great  extent,  difficult  to  dissolve,  by  reason  of  the  heat  of  the  mass.  For  this  reason, 
partly,  there  is  less  sulphate  of  iron  in  the  alum  than  might  be  expected.  To  elfcct  these 
changes  it  is  desirable  to  burn  very  slowly,  so  as  to  allow  no  loss  of  sulphurous  acid,  and,  in 
-wiusliing,  to  allow  the  water  to  stand  a  long  time  on  the  burnt  ore.  Another  method,  by 
which  the  sulphuric  acid  is  transferred  to  the  alumina,  is  the  peroxidation  of  the  protoxide 
in  the  sulphate  of  iron  ;  acid  is  by  this  means  set  free  and  begins  to  act  on  the  alumina. 

The  protosulphate  of  iron  ))eing  formed,  it  is  removed  by  boiling  down  the  liquor  until 
the  protosulphate  of  iron  crystallizes  out,  at  the  same  time  the  solution  becoming  saturated 
with  the  aluminous  salt.  The  sulphate  of  iron  is  soluble  in  0-3  of  hot  water,  the  alum  in 
0-06.  The  liquid  around  the  crystals  on  the  remaining  mother  liquor  contains  iron  also  ; 
this  is  washed  off  by  adding  pure  liquors. 


Y2 


ALUM. 


The  presence  of  lime  or  magnesia  in  the  ores  is,  of  course,  a  means  of  abstracting  acid, 
preventing  the  alumina  being  dissolved,  and  even  precipitating  it  when  dissolved. 

Knapp  says  that  at  Salzweiler,  near  Duttweiler,  in  Rhenish  Prussia,  the  roasting  of  the 
ore  takes  place  in  the  pit  or  mine.  The  stratum  of  brown  coal  which  lies  under  it,  having 
been  accidentally  set  fire  to  in  1660,  has  smouldered  till  the  present  time  without  inter- 
mission. 

When  the  ores  are  roasted,  one-half  of  the  sulphur  is  freed  and  sent  into  the  mass  or 
escapes  as  sulphurous  acid ;  and  the  remaining,  protosulphuret  of  iron,  is  afterwards  con- 
verted into  green  vitriol. 

After  calcining  and  washing  the  Campsie  ores,  the  residue  had  the  following  compo- 
sition : — 

Silica, -         -  38-40 

Alumina, 12'70 

Tcroxide  of  iron, 20-60 

Oxide  of  manganese,  -------.-  traces. 

Lime, 2-07 

Magnesia, 2-00 

Potash, 1-00 

Sulphuric  acid, 10-76 

Water, 12-27 


100-00 


It  is,  therefore,  very  far  from  being  a  complete  process  ;  but  it  is  not  considered  profitable 
to  remove  the  whole  of  the  alumina.  In  some  places  the  exhausted  ore  is  burnt  a  second 
time  with  fresh  ore,  as  at  Campsie,  but  we  are  not  told  the  estimated  exhaustion. 

In  preparing  alum  from  clay  or  shale,  it  is  of  infinite  importance  that  so  much  and  no 
more  heat  be  applied  to  the  clay  or  shale,  in  the  first  instance,  as  will  expel  the  water  of 
combination  without  inducing  contraction.  A  temperature  of  600°  F.  is  well  adapted  to 
effect  this  object,  provided  it  be  maintained  for  a  sufficient  period.  When  this  has  been 
carefully  done,  the  silicate  of  alumina  remaining  is  easily  enough  acted  upon  by  sulphuric 
acid,  either  slightly  diluted  or  of  the  ordinary  commercial  strength.  The  best  form  of 
apparatus  is  a  leaden  boiler,  divided  into  two  parts  by  a  perforated  septum  or  partition,  also 
in  lead  ;  though  on  a  very  large  scale,  brickwork  set  in  clay  might  be  employed.  Into  one 
of  the  compartments  the  roasted  clay  or  shale  should  be  put,  and  diluted  sulphuric  acid 
being  added,  the  bottom  of  the  other  compartment  may  be  exposed  to  the  action  of  a  well- 
regulated  fire,  or,  what  is  better,  heated  by  means  of  steam  through  the  agency  of  a  coil  of 
leaden  pipe.  In  this  way  a  circulation  of  the  fluid  takes  place  throughout  the  mass  of 
shale ;  and,  as  the  alumina  dissolves,  the  dense  fluid  it  produces,  falling  continually  towards 
the  bottom  of  the  boiler,  is  replaced  by  dilute  acid,  which,  becoming  in  its  turn  saturated, 
falls  like  the  first ;  and  so  on  in  succession,  until  either  the  whole  of  the  alumina  is  taken 
up,  or  the  acid  in  great  part  neutralized.  The  solution  of  sulphate  of  alumina  thus  ob- 
tained is  sometimes  evaporated  to  dryness,  and  sold  under  the  name  "  concentrated  alum  ;" 
but  more  generally  it  is  boiled  down  until  of  the  specific  gravity  of  about  1-35  ;  then  one 
or  other  of  the  carbonates  or  sulphates  of  potash  or  ammonia,  or  chloride  of  either  base,  or 
a  mixture  of  these,  is  added  to  the  boiling  fluid,  and  as  soon  as  the  solution  is  complete,  the 
whole  is  run  out  into  a  cooler  to  crystallize.  The  rough  alum  thus  made  is  sometimes  puri- 
fied by  a  subsequent  reerystallization,  after  which  it  is  "  roched  "  for  the  market — a  process 
intended  merely  to  give  it  the  ordinary  commercial  aspect,  but  of  no  real  value  in  a  chemi- 
cal point  of  view. 

The  manufacture  of  alum  is  now  taking  an  entirely  new  shape,  and  the  two  processes 
op  Mr.  Spence  and  Mr.  Pochin  threaten  to  absorb  the  whole  of  the  manufacture  in  the 
northwest. 

Mr.  Spence,  who  has  a  manufactory  of  ammonia-alum  at  Manchester,  called  the  Pendle- 
ton Alum  Works,  and  another  at  Goole,  in  Yorkshire,  has  now  become  the  largest  maker 
of  this  substance  in  the  world',  as  his  regular  production  amounts  to  upwards  of  100  tons 
per  week.  In  this  process,  which  he  has  patented,  he  uses  for  the  production  of  his  sul- 
phate-of-alumina  solution  the  carbonaceous  shale  of  the  coal  measure.  This  substance  con- 
tains from  5  to  10  per  cent,  of  carbonaceous  matter,  and,  when  ignited  by  a  small  quantity 
of  burning  coal,  the  combustion  continues  of  itself.  To  insure  this  the  shale  is  spread  into 
long  heaps  not  exceeding  18  inches  in  height,  and  having  a  brick  drain  running  along  each 
to  supply  air  ;  in  this  manner  it  slowly  calcines  :  this  process  must  be  so  conducted  as  not 
to  vitrify  the  shale.  After  calcination  it  is  boiled  and  digested  in  large  leaden  pans,  heated 
by  fire,  with  sulphuric  acid  of  1-4  specific  gravity.  After  30  to  40  hours  of  digestion  the 
sulphate  of  alumina  formed  is  run  into  another  leaden  pan,  and  the  boiling  vapor  from  the 
ammonia  liquor  of  the  gas  works  is  passed  into  it,  until  so  much  alumina  is  combined  witli 
tlie  solution  as  to  form  ammonia-alum.     The  solution  is  then  run  into  shallow  leaden  cool- 


ALUMINA,  ACETATE  OF.  73 

ers  and  the  alum  crystallizes.  It  is  then  purified  and  washed  much  in  the  usual  way,  only 
that  the  process  is  conducted  so  as  to  cause  much  less  labor  than  at  other  alum  works. 

A'um  Cake. — This  substance  owes  its  value  to  the  amount  of  sulphate  of  alumina  it 
contains,  and  is  in  fact  another  means  of  making  soluble  alumina  accessible.  We  have 
already  seen  the  many  attempts  to  obtain  alumina  from  clay,  and  the  tedious  nature  of  the 
operation  of  solution  in  acid,  as  well  as  the  long  after-processes  of  lixiviation  and  conver- 
sion into  sulphate  of  alumina,  or  into  alum,  by  reboiling  or  crystallizing.  Mr.  Pochin,  of 
Manchester  has  found  a  method  of  removing  all  the  difficulties,  both  of  the  first  and  after- 
processes.  He  uses  very  fine  China  chiy,  free  from  iron,  heats  it  in  a  furnace,  mixes  it 
thoroughly  with  acid,  and  finds  that,  when  the  process  is  managed  carefully,  the  combina- 
tion of^the  alumina  and  sulphuric  acid  is  not  only  complete,  but  so  violent  that  he  is  obliged 
to  dilute  his  acid  considerably,  in  order  to  calm  the  action.  When  mixed,  it  is  passed  into 
cisterns  with  movable  sides,  where,  in  a  few  minutes,  it  heats  violently  and  boils.  The 
thick  liquid  gradually  becomes  thicker,  until  it  is  converted  into  a  solid  porous  mass — the 
pores  being  made  by  the  bubbles  of  steam  which  rise  in  the  mass,  which  is  not  fluid  enough 
to  contract  to  its  original  volume.  The  porous  mass  is  perfectly  dry,  although  retaining  a 
large  amount  of  combined  water.  It  retains,  of  course,  all  the  silica  of  the  original  clay, 
burthis  is  in  such  fine  division  that  every  particle  appears  homogeneous.  The  silica  gives 
it  a  dryness  to  the  touch  not  easily  gained  by  the  sulphate  only. 

When  pure  sulphate  of  alumina  is  wanted  in  solution,  the  silica  is  allowed  to  precipitate 
before  using  it,  but,  in  many  cases,  the  fine  silica  is  no  hindrance  ;  then  the  solution  is 
made  use  of  at  once. — R.  A.  S. 

ALUMINA.  (Al'-O^,  51-4.)  This  is  the  only  oxide  which  the  metal  aluminium  forms, 
and  it  is  assumed  to  be  a  sesquioxide  on  account  of  its  isomorphism  with  sesquioxide  of  iron. 

The  occurrence  of  alumina  in  the  native  state  has  been  before  mentioned,  and  the  sev- 
eral minerals  will  be  found  described  elsewhere. 

It  is  obtained  in  the  state  of  hydrate  from  common  alum  (KO,  SO' ;  AFO',  8S0'-|- 
24HO)  by  adding  a  solution  of  ammonia  (or  better,  carbonate  of  ammonia)  to  the  latter 
salt,  and  boiling.  The  precipitate  is  white,  and  gelatinous  in  a  high  degree,  and  retains  the 
salts,  in  the  presence  of  which  it  has  been  formed,  with  remarkable  pertinacity,  so  that  it  is 
very  difficult  to  wash. 

By  drying  and  igniting  this  hvdrate,  the  anhydrous  alumina  is  produced  ;  but  it  may  be 
obtained  more  readily  by  heating  ammonia-alum,  (NIPO,  SO' ;  APO' 3S0' +  24HO_.) 
All  the  constituents  of  this  salt  are  volatile,  with  the  exception  of  the  alumina.  It  is 
insoluble  in  water,  but  soluble  both  in  acids  and  alkalies.  Towards  the  former  it  plays  the 
part  of  a  base,  producing  the  ordinary  alumina  salts ;  M-hilst,  with  the  latter,  it  also  enters 
into  combination,  but  in  this  case  it  is  an  acid,  forming  a  series  of  compounds  which  may 
be  called  aluminates. 

The  important  application  of  alumina  and  its  compounds  in  the  arts  of  dyeing  and  calico- 
printing,  depends  upon  a  peculiar  attraction  which  it  possesses  for  organic  bodies.  This 
affinity  is  so  strong,  that  when  digested  in  solutions  of  vegetable  coloring  matters,  the 
alumina  combines  with  and  cariies  down  the  coloring  matter,  removing  it  entirely  from  the 
solution.  Pigments  thus  obtained,  which  are  combinations  of  alumina  with  the  vegetable 
coloring  matters,  are  called  "  lakes." 

Alumina  has  not  only  an  affinity  for  the  coloring  matters,  but  at  the  same  time  also  for 
the  vegetable  fibres,  cotton,  silk,  wool,  &c.  ;  and  hence,  if  alumina  be  precipitated  upon 
cloth  in  the  presence  of  a  coloring  matter,  a  most  intimate  union  is  effected  between  the 
cloth  and  the  color.     Alumina,  when  employed  in  this  way,  is  called  a  "  mordant." 

Otlier  bodies  have  a  similai*  attraction  for  coloring  matters,  e.  (/.  binoxide  of  tin  and 
sesquioxide  of  iron:  each  of  these  gives  its  peculiar  shade  to  the  color  or  combination, 
alumina  changing  it  least. 

Soluble  Modification  of  Alumina — Mr.  Walter  Crum*  has  discovered  a  peculiar  soluble 
modification  of  alumina.  The  biacetate  of  alumina  has  been  found  by  Mr.  Crum  to  possess 
the  very  curious  property  of  parting  with  its  acetic  acid  until  the  whole  is  expelled,  by  the 
long-continued  application  of  heat  to  a  solution  of  this  salt ;  the  alumina  remains  in  tlie 
solution  in  a  soluble  allotro[)ic  condition.  Its  coagulum  with  dyewoods  is  translucent,  and 
entirely  different  from  the  opaque  cakes  formed  by  ordinary  alumina ;  hence  this  solution 
cannot  act  as  a  mordant.  But  this  solution  of  alumina,  which  is  perfectly  colorless  and 
transparent,  has  the  alumina  separated  from  it  by  the  slightest  causes.  A  minute  quantity 
of  either  an  acid,  an  alkali,  even  of  a  neutral  salt,  or  of  a  vegetable  coloring  matter,  effects 
the  change.  The  precipitated  alumina  is  insolublo  in  acids,  even  boiling  sulphuric ;  this 
shows  another  allotropic  condition.  But  it  is  dissolved  by  caustic  alkalies,  by  which  it  is 
restored  to  its  common  state. — II.  M.  W. 

ALUMIXA,  ACETATE  OF.  The  acetates  of  alumina  arc  extensively  used  in  the  arts 
on  accoimt  of  tlie  property  which  they  possess  of  being  readily  decomposed  with  deposition 
of  their  alumina  on  the  fibre  of  cloth  ;  hence  they  are  used  as  mordants,  in  the  manner  de- 

*  Chcmic.ll  Society's  Quarterly  Journal,  vi.  216. 


74  ALUMINA,  SILICATES  OF. 

scribed  under  Calico  Printing  ;  and  sometimes  in  dyeing  they  are  mixed  with  the  solution 
of  a  coloring  matter ;  in  this  the  textile  fabric  is  immersed,  whilst,  on  heating,  the  alumina 
is  precipitated  upon  the  fabric,  which,  in  consequence  of  its  affinities  before  alluded  to,  car- 
ries down  the  coloring  matter  with  it,  and  fixes  it  on  the  cloth. 

The  acetate  of  alumina  thus  employed  is  obtained  by  treating  sulphate  of  alumina  with 
neutral  acetate  of  lead,  and  filtering  off  the  solution  from  the  precipitate  of  sulphate  of 
lead.  Acetate  of  lime  is  also  used  ;  but  the  sulphate  in  this  case  does  not  leave  the  solu- 
tion so  clear  or  so  rapidly. 

According  to  Mr.  Walter  Cruni,*  the  solution  resulting  from  the  decomposition  of  sul- 
phate of  alumina  (APO\  3S0^)  by  monobasic  acetate  of  lead  contains  the  salt  APO', 
2C''H^0',  (biacetate  of  alumina,)  together  with  one  equivalent  of  free  acetic  acid,  the  com- 
pound Al-0^,  SC^H^O'  not  appearing  to  exist.  By  evaporating  this  solution  at  low  tem- 
peratures, e.  g.  in  a  very  thin  layer  of  fluid  below  38°  C,  (100  F.,)  Crura  obtained  a  fixed 
residue  completely  soluble  in  water,  the  composition  of  which,  in  the  dry  state,  approached 
AFO',  2C'IPO=-[-4riO.— 11.  M.  W. 

ALUMINA,  SILICATES  OF.  Silicate  of  alumina  is  the  chief  constituent  of  conmion 
clay,  {which  see ;)  it  occurs  also  associated  with  the  silicates  of  iron,  magnesia,  lime,  and 
the  alkalies  in  a  great  variety  of  minerals,  which  will  be  found  described  elsewhere.  The 
most  interesting  of  these  are  the  felspars  and  the  zeolites.     See  Clay. 

Of  course,  being  present  in  clay,  silicate  of  alumina  is  the  essential  constituent  of  por- 
celain and  earthenware.     See    Porcelain. — H.  M.  W. 

ALUMINA,  SULPHATE  OF.  The  neutral  sulphate  of  alumina,  Al-0\  8SO=-(-18IIO, 
which  is  obtained  by  dissolving  alumina  in  sulphuric  acid,  crystallizes  in  needles  and  plates  ; 
but  sulphuric  acid  and  alumina  combine  in  other  proportions,  c.  g.  a  salt  of  the  formula 
AFO',  3S0^-j-Al*0^  was  obtained  by  Mons,  and  the  solution  of  this  salt,  when  largely 
diluted  with  water,  splits  into  the  neutral  sulphate  and  an  insoluble  powder  containing 
APO',  3S0^  4~  2AP0^  -f-  9II0.  This  subsalt  forms  the  mineral  aluminite,  found  near 
Newhaven,  and  was  found  by  Humboldt  in  the  schists-of  the  Andes. 

The  sulphate  of  alumina  is  now  extensively  used  in  the  arts  instead  of  alum,  under  the 
name  of  "  concentrated  alum."  For  most  of  the  purposes  for  which  alum  is  employed,  the 
sulphate  of  potash  is  an  unnecessary  constituent,  being  only  added  in  order  to  facilitate  the 
purification  of  the  compound  from  iron ;  for  in  consequence  of  the  ready  crystallizability 
of  alum,  this  salt  is  easily  purified.  Nevertheless,  Wiesmann  has  succeeded  in  removing 
the  iron  from  the  crude  solution  of  sulphate  of  alumina  obtained  by  treating  clay  with  sul- 
phuric acid,  by  adding  ferrocyanide  of  potassium,  which  throws  down  the  iron  as  Prussian 
blue ;  the  solution,  when  evaporated  to  dryness,  is  found  to  consist  of  sulphate  of  alumina, 
containing  about  7  per  cent,  of  potash-alum.  1,500  tons  of  this  article  were  produced  at 
Newcastle-on-Tyne  alone  in  the  year  1854.     See  also  Alum. — H.  M.  W. 

ALUMINIUM.  {Sym.  Al.,  cquiv.  13'Y.)  The  name  Aluminium  is  derived  from  the 
Latin  alumen,  for  alum,  of  which  salt  this  metal  is  the  notable  constituent. 

The  following  is  the  method  described  by  M.  Deville  for  the  preparation  of  this  interest- 
ing metal : — 

Having  obtained  the  chloride  of  aluminium,  he  introduces  into  a  wide  glass  (or  porce- 
lain) tube  200  or  300  grammes  of  this  salt  between  two  plugs  of  asbestos,  (or  in  a  boat  of 
porcelain  or  even  copper,)  allows  a  current  of  hydrogen  to  pass  from  the  generator  through 
a  desiccating  bottle  containing  sulphuric  acid  and  t\ibes  containing  chloride  of  calcium,  and 
finally  through  the  tube  containing  the  chloride  ;  at  the  same  time  applying  a  gentle  heat  to 
the  chloride,  to  drive  off  any  free  hydrochloric  acid  which  might  be  formed  by  the  action  of 
the  air  upon  it.  He  now  introduces  at  the  other  extremity  of  the  tube  a  porcelain  boat 
containing  sodium ;  and  when  the  sodium  is  fused  the  chloride  of  aluminium  is  heated, 
until  its  vapor  comes  in  contact  with  the  fused  sodium.  A  powerful  reaction  ensues,  con- 
siderable heat  is  evolved,  and  by  continuing  to  pass  the  vapor  of  the  chloride  over  the 
sodium  until  the  latter  is  all  consumed,  a  mass  is  obtained  in  the  boat  of  the  double  chloride 
of  aluminium  and  sodium,  (NaCl,  A1"CP,)  in  which  globules  of  the  newly  reduced  metal 
are  suspended.  It  is  allowed  to  cool  in  the  hydrogen,  and  then  the  mass  is  treated  with 
water,  in  winch  the  double  chloride  is  soluble,  the  globules  of  metal  being  unacted  upon. 

These  small  globules  are  finally  fused  topjether  in  a  porcelain  crucible,  by  heating  them 
strongly  under  the  fused  double  chloride  of  aluminium  and  sodium,  or  even  under  com- 
mon salt. 

This  process,  which  succeeds  without  nuich  difficulty  on  a  small  scale,  is  performed  far 
more  successfully  as  a  manufacturing  operation.  Two  cast-iron  cylinders  are  now  employed 
instead  of  the  glass  or  porcelain  tube,  the  anterior  one  of  which  contains  the  chloride  of 
aluminium,  whilst  in  the  posterior  one  is  placed  the  sodium  in  a  tray,  about  10  lbs.  being 
employed  in  a  single  operation.  A  smaller  iron  cylinder  intermediate  between  the  two  for- 
mer is  filled  with  scraps  of  iron,  which  serve  to  separate  iron  from  the  vapor  of  chloride  of 

*  Chemical  Society's  Quarterly  Journal,  vi.  216, 


ALUMINIUM.  75 

aluminium,  by  converting  the  perchloride  of  iron  into  the  much  less  volatile  protochloride. 
They  also  separate  free  hydrochloric  acid  and  chloride  of  sulphur. 

Durin"-  the  progress  of  the  operation  the  connecting  tube  is  kept  at  a  temperature  of 
about  400''  to  600'  F.  ;  but  both  the  cylinders  are  but  very  gently  heated,  since  the  chloride 
of  aluminium  is  volatile  at  a  comparatively  low  temperature,  and  the  reaction  between  it 
and  the  sodium  when  once  commenced  generates  so  much  heat  that  frequently  no  external 
aid  is  required. 

Preparation  of  Aluminmm  by  Electrolysis. — Mr.  Gore  ha3  succeeded  in  obtaining 
plates  of  copper  coated  with  aluminium  by  the  electrolysis  of  solutions  of  chloride  of 
aluminium,  acetate  of  alumina,  and  even  common  alum  ;*  but  the  unalloyed  metal  cannot 
be  obtained  by  the  electrolysis  of  solutions.  Deville,  however,  produced  it  in  considerable 
quantities  by  the  method  originally  suggested  by  Bunsen,  viz.,  by  the  electrolysis  of  the 
fused  double  chloride  of  aluminium  and  sodium,  (NaF,  AFF' ;)  but  since  this  process  is 
far  more  troublesome  and  expensive  than  its  reduction  by  sodium,  it  has  been  altogether 
superseded. 

Preparation  of  Aluminium  from  K-ryolite. — So  early  as  March  30,  1855,  a  specimen 
of  aluminium  was  exhibited  at  one  of  the  Friday  evening  meetings  of  the  Royal  Institu- 
tion, which  had  been  obtained  in  Dr.  Percy's  laboratory  by  Mr.  Allan  Dick,  by  a  process 
entirely  different  from  that  of  Deville,  which  promised,  on  account  of  its  great  simplicity, 
to  supersede  all  others,  f  It  consisted  in  heating  small  pieces  of  sodium,  placed  in  alter- 
nate layers  with  powdered  kryolite,  a  mineral  now  found  in  considerable  abundance  in 
Greenland,  which  is  a  double  fluoride  of  aluminium  and  sodium,  analogous  to  the  double 
chloride  of  aluminium  and  sodium,  its  formula  being  NaF,  Al'-F^  The  process  has  the 
advantage  that  one  of  the  materials  is  furnished  ready  formed  by  nature. 

The  experiment  was  only  performed  on  a  small  scale  by  Mr.  Dick  in  a  platinum  crucible 
lined  with  magnesia ;  the  small  globules  of  metal,  which  were  obtained  at  the  bottom  of 
the  mass  of  fused  salt,  being  subsequently  fused  together  under  chloride  of  potassium  or 
common  salt. 

Before  the  description  of  these  experiments  was  published,  M.  Rose,  of  Berlin,  pub- 
lished a  paper  in  September,  1855,  on  the  same  subject. :}:  In  Rose's  experiments  he  em- 
ployed cast-iron  crucibles,  in  which  were  heated  ten  parts  of  a  mixture  of  equal  weights  of 
kryolite  and  chloride  of  potassium  with  2  parts  of  sodium.  The  aluminium  was  obtained  in 
small  globules,  which  were  fused  together  under  chloride  of  potassium,  as  in  Mr.  Dick's 
experiments. 

Rose  experienced  a  slight  loss  of  aluminium  by  fusion  under  chloride  of  potassium,  and 
found  it  more  advantageous  to  perform  this  fusion  under  a  stratum  of  the  double  chloride 
of  aluminium  and  sodium,  as  Deville  had  done. 

He  never  succeeded  in  extracting  the  whole  quantity  of  aluminium  present  in  the  kryo- 
lite, (13  per  cent.,)  chiefly  on  account  of  the  ready  oxidizability  of  the  metal  when  existing 
in  a  very  finely  divided  state,  as  some  of  it  invariably  does. 

It  does  not  appear  that  any  attempt  has  since  been  made  to  obtain  aluminium  on  the 
large  scale  from  kryolite,  probably  from  the  supply  of  the  mineral  not  proving  so  abundant 
as  was  at  one  time  anticipated. 

In  all  the  processes  which  have  been  found  practicable  on  any  considerable  scale,  for  the 
manufacture  of  aluminium,  the  powerful  affinities  of  sodium  are  employed  for  the  purpose 
of  eliminating  it  from  its  compounds.  The  problem  of  the  diminution  of  the  price  of 
aluminium  therefore  resolves  itself  into  the  improvement  of  the  methods  for  procuring 
sodium,  so  as  to  diminish  the  cost  of  the  latter  metal.  M.  Deville's  attention  was  therefore 
directed,  in  the  early  steps  of  the  inquiry,  to  this  point ;  and  very  considerable  improve- 
ments have  been  made  by  him,  which  will  be  found  fully  described  under  the  head  of 
Sodium. 

Deville§  has  since  suggested  the  employment  at  once  of  the  double  salt  of  chloride  of 
aluminium  and  chloride  of  sodium,  (XaCl,  AFCl',)  instead  of  the  simple  chloride  of 
aluminium,  so  as  to  obtain  the  metal  by  means  of  sodium.  He  uses  400  parts  of  this 
double  salt,  200  of  common  salt,  200  of  fluor  spar,  and  75  to  80  of  sodium.  The  above- 
mentioned  salts  are  dried,  powdered,  and  mixed  together ;  then  with  these  the  sodium,  in 
small  pieces,  is  mixed,  and  the  whole  heated  in  a  crucible  under  a  layer  of  common  salt. 
After  the  reaction  is  complete,  the  heat  is  raised  so  as  to  promote  the  separation  of  the  • 
aluminium  in  the  form  of  a  button.  It  was  found,  however,  that  kryolite  was,  with  advan- 
tage, substituted  for  the  fluor  spar. 

C.  Brunner||  employs  artificially  prepared  fluoride  of  aluminium  ;  but  this  method  can- 
not offer  any  advantage  over  the  employment  of  the  chloride,  which  is  cheaper,  or  the 
kryolite,  which  nature  affords. 

Properties. — The  metal  is  white,  but  with  a  bluish  tinge ;  and  even  when  pure  has  a 
lustre  far  inferior  to  silver. 

*  Phil.  Mac.  vii.  20T.  +  Phil.  Mag.  x.  304.  J  Pocgrendorf,  Annalcn,  and  Phil.  Mag.  s.  233. 

§  Ann.  de  China,  et  Phys.  xlvi.  415.  ||  Chemical  Gazette,  1856,  Sfe. 


76  ALUMINIUM. 

Specific  gravity,  2-56,  and,  when  hammered,  2-6'7. 

Conducts  electricity  eight  times  better  than  iron,  and  is  feebly  magnetic. 

Its  I'using  point  is  between  the  melting  points  of  zinc  and  silver. 

By  ik'ctrolysis  it  is  obtained  in  forms  which  Deville  believes  to  be  regular  octahedra  ; 
but  Rosf,  who  has  also  occasionally  obtained  aluminium  in  a  crystalline  state,  (from  kryo- 
lite,)  denies  that  they  belong  to  the  regular  system. 

When  pure,  it  is  unoxidized  even  in  moist  air ;  but  most  of  the  commercial  specimens 
(probably  from  impurities  present  in  the  metal)  become  covered  with  a  bluish-gray  tarnish. 
it  is  unaffected  by  cold  or  boiling  water ;  even  steam  at  a  red  heat  is  but  slowly  decomposed 
by  it. 

It  is  not  acted  upon  by  cold  nitric  acid,  and  only  very  slowly  dissolved  even  by  the  boil- 
ing acid  ;  scarcely  attacked  by  dilute  sulphuric  acid,  but  readily  dissolved  by  hydrochloric 
acid,  with  evolution  of  hydrogen. 

Sulphuretted  hydrogen  and  sulphides  have  no  action  upon  it ;  and  it  is  not  even  attacked 
by  fused  hydrated  alkalies.  Professor  'Wheatstone*  has  shown  that  in  the  voltaic  series, 
aluminium,  although  having  so  small  an  atomic  number,  and  so  low  a  specific  gravity,  is 
more  electro-negative  than  zinc  ;  but  it  is  positive  to  cadmium,  tin,  lead,  iron,  copper,  and 
platinum. 

Impurities  in  Aluminium. — Many  of  the  discrepancies  in  the  properties  of  aluminium, 
as  obtained  by  different  experimenters,  are  due  to  the  impurities  which  are  present  in  it. 

If  the  naphtha  be  not  carefully  removed  from  the  sodium,  the  aluminium  is  liable  to 
contain  carbon. 

Frequently,  in  preparing  aluminium,  by  the  action  of  the  chloride  on  sodium,  by  Dc- 
ville's  original  process,  copper  boats  have  been  used  for  holding  the  sodium  ;  in  this  case 
the  metal  becomes  contaminated,  not  only  with  copper,  but  also  with  any  other  metal  which 
may  be  present  in  the  copper — c.  g.  Salm-Horstmar  f  found  copper  in  the  aluminium  sold 
in  Paris,  and  Erdmann  detected  zinc  ;  %  and  in  every  case  the  metal  is  very  liable  to  become 
mixed  with  silicon,  either  from  the  earthenware  tubes,  boats,  or  crucibles ;  hence  Salvetat 
found,  even  in  the  aluminium  prepared  by  Deville  himself,  2-87  per  cent,  of  silicon,  2-40 
of  iron,  6-38  of  copper,  and  traces  of  lead. 

The  following  analj-sis  of  commercial  aluminium  was  communicated  to  the  British  Asso- 
ciation, at  its  meeting  in  1857,  by  Professor  Mallet : — 

Made  in  Paris.  Made  in  Berlin. 

Al 92-9C9 96-253 

Fe 4-882 3-293 

Si 2-149 0-454 

Ti  -         -         -         -         -         -        trace         .....        trace 

100-00  100-00 

AUoysi  of  Aluminimn. — Very  small  quantities  of  other  metals  suffice  to  destroy  the 
malleability  and  ductility  of  aluminium.  An  alloy  containing  only  J^  of  iron  or  copper 
cannot  be  worked,  and  the  presence  of  jL  copper  renders  it  as  brittle  as  glass.  Silver 
and  gold  produce  brittleness  in  a  less  degree.  An  alloy  of  5  parts  of  silver  with  100  of 
aluminium,  is  capable  of  being  worked  like  the  pure  metal,  but  it  is  harder,  and  therefore 
susceptible  of  a  finer  polish ;  whilst  the  alloy,  containing  10  per  cent,  of  gold,  is  softer, 
but,  nevertheless,  not  so  malleable  as  the  pure  metal.  The  presence  of  even  -j-Jo  P''"'^  ^^ 
bismuth  renders  aluminium  brittle  in  a  high  degree. 

These  statements  by  Tissier,§  however,  require  confirmation ;  for  Debray  states  that 
aluminium  remains  malleable  and  tough  when  containing  as  much  as  8  per  cent,  of  iron,  or 
10  per  cent,  of  copper,  but  that  a  larger  quantity  of  either  of  these  metals  renders  it 
brittle. 

It  is  curious  that  only  3  per  cent,  of  silver  are  sufficient  to  give  aluminium  the  bril- 
liance and  color  of  pure  silver,  over  w/iicli  the  allot/  has  the  great  advantage  of  not  being 
blackened  by  sulphuretted  hydrogen. 

On  the  other  hand,  small  quantities  of  aluminium  combined  with  other  metals  change 

their  properties  in  a  remarkable  manner.     Thus  copper  alloyed  with  only  y'^  of  its  weight 

•  ofiiluminium  has  the  color  and  brilliance  of  gold,  and  is  still  very  malleable,  (Tissier ;)  and 

when  the  aluminium  amounts  only  to  Vg,  {i.  c.  20  per  cent.,)  the  alloy  is  quite  white, 

(Bchrat/.) 

An  alloy  of  90  parts  of  copper  and  10  of  aluminium  is  harder  than  common  bronze, 
and  is  capable  of  being  worked  at  high  temperatures  easier  than  the  best  varieties  of  iron. 
Larger  fiuantities  of  aluminium  render  the  metal  harder  and  brittle. — Debray.  \\ 

An  alloy  of  100  parts  of  silver  with  5  of  aluminium  is  as  hard  as  the  alloy  employed  in 

*  Phil.  Ma?.  X.  14-3.  t  Journal  pr.  Chcm.  Ixvii.  40S. 

t  .Toiirnal  pr.  Cliem.  Ixvii.  494  §  C.  and  J.  Tissier,  Comptes  Eondus,  sliii.  6S5. 

J  ("DUiptcs  IJendus,  xliii,  925. 


ALUM,  NATIVE.  77 

the  silver  coinage,  although  the  other  properties  of  the  silver  remain  unchanged,  {Tissier.) 
Similar  alloys  have  likewise  been  prepared  by  Dr.  Percy.* 

Messrs.  Calvert  and  Johnson  describef  an  alloy  of  25  parts  aluminium  to  75  of  iron, 
which  has  the  valuable  property  of  nol  oxidizing  by  exposure  to  moist  air. 

Uses  of  Aluminium. — No  very  important  apphcation  of  aluminium  has  yet  been  made, 
althou<^h  at  the  time  M.  Deville's  experiments  were  commenced,  sanguine  hopes  were 
entertained  that  aluminium  might  be  produced  at  a  price  sufficiently  low  to  admit  of  its 
practical  application  on  a  large  scale,  these  anticipations  have  not  been  realized  ;  and  as  yet, 
on  account  chiefly  of  its  high  price,:|:  the  applications  which  have  been  made  of  this  inter- 
esting metal  are  but  few. 

Its  low  specific  gravity,  combined  with  sufficient  tenacity,  recommends  it  for  many 
interesting  uses.  The  fractional  weights  used  by  chemists,  which  are  made  of  platinum, 
are  so  extremely  small  that  they  are  constantly  being  lost ;  their  much  greater  volume  in 
aluminium  renders  this  metal  peculiarly  suitable.  In  the  construction  of  the  beams  of  bal- 
ances, strength  combined  with  lightness  are  desiderata ;  and  M.  Deville  has  had  very  beau- 
tiful balance  beams  made  of  this  metal ;  but  at  present  its  high  price  has  prevented  their 
extensive  adoption. 

These  same  qualities  render  this  metal  suitable  for  the  construction  of  helmets  and  other 
armor ;  but  at  present  these  are  but  curiosities,  and  are  likely  to  remain  so,  unless  some 
cheaper  method  of  eliminating  the  metal  than  by  the  agency  of  sodium  be  discovered. 

Its  quality  of  being  unacted  upon  by  oxygen,  sulphuretted  hydrogen,  and  many  acids, 
would  suggest  numerous  applications,  if  it  were  sufficiently  cheap ;  e.  g.  it  might  be  used 
for  coating  other  metals,  as  iron,  lead,  &c.,  to  protect  them  from  rust,  instead  of  paint. § 
It  would  be  particularly  useful  for  covering  the  pipes  and  cisterns  employed  in  water  supply, 
and  thus  preventing  the  accidents  which  are  constantly  resulting  from  the  action  of  water 
on  lead. 

This  metal  has  been  proposed  for  making  spoons,  &c.,  instead  of  silver.  It  certainly 
has  the  advantage  of  not  being  blackened  by  sulphuretted  hydrogen  ;  but  those  which  the 
writer  has  seen  have  a  dull  leaden  hue, — far  inferior,  even,  to  somewhat  tarnished  silver  in 
brilliance, — and  would  certainly  not  be  held  in  high  esteem  by  the  public. 

It  has  been  suggested  to  employ  aluminium,  on  account  of  its  sonorousness  and  duc- 
tility, for  making  piano-forte  wires.  It  was  also  imagined  that  it  might  be  used  in  making 
bells ;  but  Mr.  Denison  has  quite  set  this  question  at  rest.  No  one  who  heard  the  sound 
of  his  aluminium  bell  will  again  think  of  such  an  application. 

Probably  one  of  the  most  interesting  of  the  applications  of  aluminium  (at  least  in  a 
scientific  point  of  view)  that  has  been  made,  is  the  recent  one  by  Deville  and  Wohler,  of 
employing  it  in  the  production  of  crystalline  allotropic  modifications  of  certain  other  ele- 
ments hitherto  unknown  in  that  state ;  e.  g.  boron,  silicon,  and  titanium,  {which  sec.)  It 
depends  upon  the  fact  that  these  elements,  in  the  amorphous  state,  dissolve  in  fused  alumin- 
ium, and,  on  cooling  the  molten  solution,  they  slowly  separate  from  the  aluminium  in  the 
crystalline  state. 

Our  first  importation  of  aluminium  was  in  1856,  to  the  value  of  £35. — H.  M.  W. 

ALUMINIUM,  CHLORIDE  OF,  (Al-CP— 133-9.)  Preparatio7i.— Chloride  of  alumin- 
ium cannot  be  prepared  by  treating  alumina  with  hydrochloric  acid,  as  in  the  case  of  most 
chlorides ;  for  on  evaporating  the  solution  to  dryness,  hydrochloric  acid  is  evolved  and 
alumina  alone  remains. 

The  method  at  present  used  is,  in  principle,  the  same  as  that  originally  suggested  by 
ffirsted,  which  has  since  found  numerous  other  applications.  It  is  impossible  to  convert 
alumina  into  the  chloride  by  the  direct  action  of  chlorine  alone ;  at  any  temperature  the 
chlorine  is  as  incapable  of  displacing  the  oxj'gcn  from  the  alumina  as  it  would  from  lime. 
But  if  the  attraction  of  the  chlorine  for  the  metal  be  supported  by  the  affinity  of  carbon 
for  the  oxygen,  then  the  compound  is,  as  it  were,  torn  asunder,  carbonic  acid  or  carbonic 
oxide  resulting  on  the  one  hand,  and  the  chloride  of  aluminium  on  the  other. 

On  the  large  scale  the  chlorine  is  p;issed  over  a  previously  ignited  mixture  of  clay  and 
coal  tar,  contained  in  retorts  like  those  used  in  the  manufacture  of  coal  gas,  which  are 
heated  in  a  furnace ;  the  chloride,  which  on  account  of  its  volatility  is  carried  off,  being 
condensed  in  a  chamber  lined  with  plates  of  earthenware,  where  it  is  deposited  in  a  crystal- 
line mass. 

Properties. — It  is  a  yellowish  crystalline  solid,  readily  decomposed  by  the  moisture  of 
the  air  into  hydrochloric  acid  and  alumina,  volatile  at  a  dull  red  heat.  It  is  very  soluble  iq 
water,  but  cannot  l)c  recovered  by  evaporating  tlie  solution. — II.  M.  W. 

ALUM,  NATIVE.  This  term  includes  several  compounds  of  sulphate  of  alumina  with 
the  sulphate  of  some  other  base,  as  magnesia,  potash,  soda,  the  protoxides  of  iron,  manga- 

*  Proceedlnss  of  tho  Royal  Institution,  March  14.  18r)G.  ,  t  Pliil.  Majr.  x.  245. 

I  Tlio  present  price  of  Aliiniiniuin  in  Lon(l(m  is  Hn.  \>CT  ounce,  whilst  only  in  M.'vrch,  1S50,  just  after 
M.  Dovillii's  experiments  li.id  been  made,  it  cost  3^.  per  ounce. 

§  It  is  calculated  that  more  than  a  million  sterliiii;  is  annually  expended  i!i  the  inetropolis  on  tho 
paint  necessary  to  protect  tho  iron-work  from  decay. — lier.  J.  lAtrlow. 


78  ALUM  SHALE. 

nese,  &c.  They  occur  generally  as  efflorescences,  or  in  fibrous  masses  ;  when  crystallized, 
they  assume  octahedral  forms. 

Native  alum  is  soluble  in  water,  and  has  an  astringent  taste,  like  that  of  the  alum  of 
commerce. — H.  W.  B. 

ALUM  SHALE.  The  chief  natural  source  from  which  the  alum  of  commerce  is  de- 
rived in  this  country.  It  occurs  in  a  remarkable  manner  near  Whitby,  in  Yorkshire,  and 
at  Ilurlet  and  Campsie,  near  Glasgow.  A  full  description  of  the  alum  shale,  and  of  the 
processes  by  which  the  crystallizable  alum  is  separated,  will  be  found  under  Alum. 

AMALGAM.  When  mercury  is  alloyed  with  any  metal,  the  compound  is  called  an 
amalgam  of  that  metal ;  as  for  example,  an  amalgam  of  tin,  bismuth,  &c. 

Some  amalgams  are  solids  and  others  fluids ;  the  former  are  often  crystalline,  and  the 
latter  may  be  probably  regarded  as  the  solid  amalgam  dissolved  in  mercury. 

Silver  Amalgam  may  be  formed  by  mixing  finely-divided  silver  with  mercury.  The 
best  process  is  to  precipitate  silver  from  its  solution  by  copper,  when  we  obtain  it  in  a  state 
of  fine  powder,  and  then  to  mix  it  with  the  mercury. 

A  native  amalgam  of  mercury  and  silver  occurs  in  fine  crystals  in  the  mines  of  the 
Palatinate  of  Moschellandsberg  :  it  is  said  to  be  found  where  the  veins  of  copper  and  silver 
intersect  each  other.  Dana  reports  its  existence  in  Hungary  and  Sweden,  at  Allemont,  in 
Dauphine  ;  Almaden,  in  Spain,  and  in  Chili ;  and  he  quotes  the  following  analyses : — 

Silver.  Mercury. 

Moschellandsberg,        -         -         -     36-0  ...     64-0  by  Klaproft. 

Ditto,  -         -         -     25-0  -         -         -     'ZS.S    "  Heyer. 

Allemont, 27-5  :         -         -     '72-5    "  Cordier. 

If  six  parts  of  a  saturated  solution  of  nitrate  of  silver  with  two  parts  of  a  saturated 
solution  of  the  protonitrate  of  mercury  are  mixed  with  an  amalgam  of  silver  one  part  and 
mercury  seven,  the  solution  is  speedily  filled  with  beautiful  arborescent  crystals— the  Arbor 
Biance,  the  tree  of  Diana, — or  the  silver  tree. 

Gold  Amalgam  is  made  by  heating  together  mercury  with  grains  of  gold,  or  gold-foil ; 
when  the  amalgam  of  gold  is  heated,  the  mercury  is  volatilized  and  the  gold  left.  This 
amalgam  is  employed  in  the  process  known  as  that  of  fire-gilding,  although,  since  electro- 
gilding  has  been  introduced,  it  is  not  so  frequently  employed.  A  gold  amalgam  is  obtained 
from  tiie  platinum  region  of  Columbia  -,  and  it  has  been  reported  from  California,  especially 
from  near  Mariposa.  Schneider  give  its  composition,  mercury,  5*7 "40;  gold,  38-89 ;  sil- 
ver, 5'0. 

Tin  Amalgam. — By  bringing  tin-foil  and  mercury  together,  this  amalgam  is  formed, 
and  is  used  for  silvering  looking-glasses.  (See  Silvering  Glass.)  If  melted  tin  and  mer- 
cury are  brought  together  in  the  proportion  of  three  parts  mercury  and  one  part  tin,  the 
tin  amalgam  is  obtained  in  cubic  crystals. 

Electric  Machine  Amalgam. — Melt  equal  parts  of  tin  and  zinc  togcttier,  and  combine 
these  with  three  parts  of  mercury  :  the  mass  must  be  shaken  until  it  is  cold  ;  the  whole  is 
then  rubbed  down  with  a  small  quantity  of  lard,  to  give  it  the  proper  consistence. 

Amalgam  Copper,  for  stopping  teeth.  The  French  dentists  have  long  made  use  of  this 
for  stopping  teeth.  It  is  sold  in  small  rolls  of  about  a  drachm  and  a  half  in  weight ;  it  is 
covered  with  a  grayish  tarnish,  has  a  hardness  much  greater  than  that  of  bone,  and  its 
cohesion  and  solidity  are  considerable.  When  heated  nearly  to  the  point  of  boiling  water 
this  amalgam  swells  up,  drops  of  mercury  exuding,  which  disappear  again  on  the  cooling  of 
the  substance.  If  a  piece,  thus  heated,  be  rubbed  tip  in  a  mortar,  a  plastic  mouldable  mass, 
like  poor  clay,  is  obtained,  the  consistence  of  which  may,  by  continued  kneading,  be 
increased  to  that  of  fat  clay.  If  the  moulded  mass  be  left  for  ten  or  twelve  hours,  it 
hardens,  acquiring  again  its  former  properties,  without  altering  its  specific  gravity.  Hence, 
the  stopping,  after  it  has  hardened,  remains  tightly  fixed  in  the  hollow  of  the  tooth.  The 
softening  and  hardening  may  be  repeated  many  times  with  the  same  sample.  Pcttenkofer 
ascribes  these  phenomena  to  a  state  of  amorphism,  with  which  the  amalgam  passes  from 
the  crystalline  condition  in  the  process  of  softening.  All  copper  amalgams  containing  be- 
tween  0-25  to  0-30  of  copper  exhibit  the  same  behavior.  The  above  chemist  recommends 
as  the  best  mode  of  preparing  this  amalgam,  that  a  crystalline  paste  of  sulphate  of  sub- 
oxide of  mercury  (prepared  by  dissolving  mercury  in  hydrated  sulphuric  acid  at  a  gentle 
heat)  be  saturated  under  water  at  a  temperature  of  from  GO"  to  70',  with  finely  divided 
rcguline  copper,  (prepared  by  precipitation  from  sulphate  of  copper  with  iron.)  One  por- 
tion of  the  copper  precipitates  the  mercury,  with  formation  of  sulphate  of  copper ;  the 
other  portion  yields  with  mercury  an  amalgam  :  100  parts  of  dissolved  mercury  require  the 
copper  precipitated,  by  iron,  from  232-5  parts  of  sulphate  of  copper.  As  in  dissolving  the 
mercury  the  protoxide  is  easily  formed  instead  of  the  suboxide,  particularly  if  too  high  a 
temperature  bo  maintained,  it  is  advisable,  in  order  to  avoid  an  excess  of  mercury  in  the 
amalgam,  to  take  223  parts  of  sulphate  of  copper,  and  to  add  to  the  washed  amalgam, 
which  is  kept  stirred,  a  quantity  of  mercury  in  minute  portions,  corresponding  to  the 


AMMONIA. 


79 


amount  of  suboxide  contained  in  the  mercury  salt,  until  the  whole  has  become  sufficiently 
plastic.  This  amalgam  may  be  obtained  by  moistening  finely-divided  copper  with  a  few 
drops  of  a  solution  of  nitrate  of  suboxide  of  mercury,  and  then  triturating  the  metal  with 
mercury  in  a  warmed  mortar.  The  rubbing  may  be  continued  for  some  time,  and  may  be 
carried  on  under  hot  water,  mercury  being  added  until  the  required  consistence  is  attained. 

A  remarkable  depression  of  temperature  during  the  combination  of  amalgams  has  been 
observed  bv  several  chemists. 

Dobereiner  states  that  when  816  grains  of  amalgam  of  lead  (404  mercury  and  412  lead) 
were  mixed,  at  a  temperature  of  68",  with  688  grains  of  the  amalgam  of  bismuth,  {H)i 
mercury  and'  284  bismuth,)  the  temperature  suddenly  fell  to  30^,  and  by  the  addition  of  808 
"•rains  of  mercury  (also  at  68")  it  became  as  low  as  17' ;    the  total  depression  amounting 

In  certain  proportions  of  mixture  of  the  constituents  of  fusible  metal  (tin,  lead,  and 
bismuth)  with  mercury,  Dobereiner  formed  surprising  depressions  of  temperature ;  the  tem- 
perature, he  records  of  one  experiment,  sank  instantly  from  65°  to  14°. 

AMBER  VARNISH.  Amber  is  composed  of  a  mixture  of  two  resins,  which  are  soluble 
in  alcohol  and  ether,  and  in  some  of  the  recently-discovered  hydro-carbon  compounds. 
Varnishes  are  therefore  prepared  with  them,  and  sold  under  the  name  of  ay/iber  spirit  var- 
nixfies  ;  but  these  are  frequently  composed  of  either  copal  or  mastic.  They  have  been 
much  used  for  varnishing  collodion  pictures. 

AMBERGRIS.  It  is  found  on  various  parts  of  the  cast  coast  of  Africa,  as  well  as  in  the 
eastern  seas.  The  best  is  ash-colored,  with  yellow  or  blackish  veins  or  spots,  scarcely  any 
taste,  and  very  little  smell  unless  heated  or  much  handled,  when  it  yields  an  agreeable  odor. 
Exposed  in  a  silver  spoon  it  melts  without  bubble  or  scum,  and  on  the  heated  point  of  a 
knife  it  vaporizes  completely  away. 

The  chemical  composition  of  ambergris  is  represented  by  the  following  formula, 
q33jj3:q  'J'p^g  ambergris  is  very  rarely  met  with,  by  far  the  largest  proportion  of  that 
which  is  sold  as  ambergris  being  a  preparation  scented  with  civet  or  musk. 

In  France  the  duty  upon  ambergris  is  62  francs  per  kilogramme  when  imported  in 
French  vessels,  and  67  francs  when  imported  in  foreign  vessels. 

Ambergris  is  at  this  time  (1858)  worth  16.s.  an  ounce  in  England.  Mr.  Temple,  of 
Belize,  British  Honduras,  speaks  of  an  odorous  substance  thrown  off  by  the  alligator,  which 
appears  to  resemble  ambergris. 

AMETHYST.  {Amethyste  occidentale,  Fr.  ;  Eisenkeisel^  Germ.)  One  of  the  vitreous 
varieties  of  quartz,  composed  of  pure  silica  in  the  insoluble  state — that  is,  it  will  not  dis- 
solve in  a  potash  solution.  It  belongs  to  the  rhombohedral  system,  and  is  found  either  in 
groups  of  crystals  or  lining  the  interior  of  geodes  and  pebbles.  It  is  infusible  before  the 
blowpipe,  and  is  not  affected  by  acids.  It  is  of  a  clear  purple  or  bluish-violet  tint ;  but  the 
color  is  frequently  irregularly  diffused,  and  gradually  fades  into  white.  The  color  is  sup- 
posed to  be  due  to  the  presence  of  a  small  percentage  of  manganese,  but  Heintz  attributes 
it  tJ  a  compound  of  iron  and  soda.  The  amethyst,  from  the  beauty  of  its  color,  has  always 
been  esteemed  and  used  in  jewellery.  It  was  one  of  the  stones  called  by  the  ancients  a^UOua- 
Tos,  a  name  which  they  conferred  on  it  from  its  supposed  power  of  preserving  the  wearer 
from  intoxication.  The  most  beautiful  specimens  are  procured  from  India,  Ceylon,  and 
Persia,  where  they  occur  in  geodes  and  pebbles :  it  is  also  found  at  Oberstein,  in  Sax- 
ony ;  in  the  Palatinate  ;  in  Transylvania ;  near  Cork,  and  in  the  Island  of  May,  in  Ireland. 
— H.  W.  B.  . 

AMETHYST,  ORIENTAL.  {Amtthijste  orientale,  Fr.  ;  Bcmanthspath,  Germ.)  Tiiis 
term  is  applied  to  those  varieties  of  corundum  which  are  of  a  violet  color.  See  Cokcndum, 
— H.  W.  B. 

AMIANTHUS  is  the  name  given  to  the  whiter  and  more  delicate  varieties  of  asbestus, 
which  possess  a  satin-like  lustre,  in  consequence  of  the  greater  separation  of  the  fibres  of 
wliich  they  are  composed.  A  variety  of  amianthus  (the  amianthoide  of  Ilaiiy)  is  found  at 
Oisans,  in  France,  the  fibres  of  which  are  in  some  degree  elastic.  The  word  amianthus 
(from  afilavros,  undefiled)  is  expressive  of  the  easy  manner  by  which,  when  soiled,  it  may 
bo  cleansed  and  restored  to  its  original  purity,  by  being  heated  to  redness  in  a  fire.  See 
ASBESTIS. — H.  W.  B. 

AMMONIA.  NIP,  eqv.  17.  {Atnniomaque,  Fr.  ;  Ammoniak,  Germ.)  The  name 
given  to  the  alkaline  gas  which  is  the  volatile  alkali  of  the  early  chemists.  The  real  origin 
(Tf  this  word  is  not  known.  Some  suppose  it  to  be  from  Ammon,  a  title  of  Jupiter,  near 
whose  temple  in  Upper  Egypt  it  was  generated.  Others  suppose  it  to  be  from  Ammonia, 
a  Cyrenaic  territory  ;  whilst  others  again  have  deduced  it  from  &ixfios,  sand,  as  it  was  found 
in  sandy  ground. 

It  is  probable  that  Pliny  was  acquainted  with  the  pungent  smell  of  ammonia.  Dr. 
Black,  in  1750,  first  isolated  it,  proving  the  distinction  between  it  and  its  carbonate,  with 
which  it  had  been  confounded  up  to  that  time  ;  and  it  was  soon  afterwards  more  fully  inves- 
tigated by  Priestley. 


80  AMMONIA. 

Ammonia  being  a  product,  not  only  of  the  destructive  distillation  of  organic  bodies  con- 
taining nitrogen,  but  also  of  their  decay,  it  exists  in  the  atmosphere,  in  a  large  amount,  if 
considered  in  the  aggregate,  although,  by  examining  any  particular  specimen  of  air,  the 
quantity  appears  small.  Nevertheless,  this  small  quantity  of  ammonia  would  seem  to  be 
exceedingly  important  in  developing  the  nitrogenized  constituents  of  plants.  Liebig  be- 
lieves that  the  nitrogen  of  plants  is  exclusively  derived  from  the  ammonia  present  in  the 
air ;  but  the  opinions  of  chemists  are  divided  on  this  point.  Boussingault  *  supports  I^e- 
big's  view,  but  it  is  opposed  by  Mulder  and  Yille. 

From  the  air,  ammonia  and  its  salts  are  carried  down  by  the  rain.  This  fact  has  been 
placed  beyond  all  doubt  by  Liebig ;  and  even  the  variations  in  the  quantity  have  been  de- 
termined by  Boussingault,  and  more  recently  by  Mr.  Way.  By  the  rain  water  it  is  carried 
into  rivers,  and  ultimately  into  the  sea,  in  which  chloride  of  ammonium  has  been  detected 
by  Dr.  Marcet.  It  has  likewise  been  detected  in  mineral  springs,  especially  brine  springs, 
and  even  in  common  salt. —  Vogcl. 

Ammonia  is  present  in  the  exhalations  from  volcanoes.  During  the  eruption  of  Vesu- 
vius in  1*794,  the  quantity  of  sal  ammoniac  discharged  by  the  mountain  was  so  great,  that 
the  peasants  collected  it  by  hundredweights,  (Bischof;)  and  in  the  last  eruption  of  Hecla, 
in  Sept.,  1845,  a  similar  phenomenon  was  observed  ;  and,  according  to  Ferrara,  it  is  some- 
times found  in  such  quantity  at  Etna,  that  a  very  profitable  trade  has  been  carried  on  in  it. 
Dr.  Daubeny  thinks  that  the  volcanic  ammonia  is  produced  by  the  action  of  water  upon 
mineral  nitrides,  (perhaps  the  nitrides  of  silicon,)  similar  in  properties  to  the  nitrides  of 
Titanium  and  Boron,  which  have  been  recently  more  carefully  examined  by  M.  St.  Claire 
Devil)  c.  Ammoniacal  salts  have  likewise  been  found  as  a  sublimate  arising  from  the  com- 
bustion of  coal  strata. 

The  great  supply  of  ammonia  and  its  salts  is  derived  from  the  destructive  distillation  of 
organic  bodies,  animal  and  vegetable,  containing  nitrogen  ;  but  its  salts  exist  in  plants,  and 
to  a  nmch  larger  extent  in  the  liquid  and  solid  excrements  of  animals.  As  a  urate,  it  forms 
the  chief  constituent  of  the  excrement  of  the  boa,  as  well  as  that  of  many  birds,  hence  the 
large  quantity  of  ammoniacal  salts  in  guano.     See  Guano. 

Formation  of  Ammonia. — No  process  has  yet  been  devised  for  inducing  the  direct  com- 
bination of  nitrogen  and  hydrogen  to  produce  ammonia  ;  but  under  the  disposing  influence 
of  the  production  of  other  compounds,  in  the  presence  of  these  elements,  as  well  as  when 
these  gases  are  presented  to  each  other  in  the  nascent  state,  their  union  is  effected. 

Thus,  when  electric  sparks  are  passed  through  a  mixture  of  nitrogen  and  oxygen  in  the 
presence  of  hydrogen  and  aqueous  vapor,  nitrate  of  ammonia  is  generated.  If,  while  zinc 
is  being  dissolved  in  sulphuric  acid,  nitric  acid  be  added,  much  ammonia  is  formed,  {Nes- 
bit ;)  so  again,  if  hydrogen  and  l^inoxide  of  nitrogen  be  passed  over  spongy  platinum,  tor- 
rents of  ammonia  are  produced,  the  hydrogen  converting  the  oxygen  of  the  binoxide  into 
water,  when  the  nitrogen,  at  the  moment  of  its  liberation,  combines  with  the  hydrogen  to 
form  ammonia. 

It  has  even  been  proposed  to  carry  out  this  last  method  on  a  manufacturing  scale. 

Messrs.  Crane  and  Jullicn,  in  their  patent  of  January  18,  1848,  describe  a  method  of 
manufacturing  ammonia  in  the  state  of  carbonate,  hydrocyanate,  or  free  ammonia,  by  pass- 
ing any  of  the  oxygen  compounds  of  nitrogen,  together  with  any  compound  of  hydrogen 
and  carbon,  or  any  mixture  of  hydrogen  with  a  compound  of  carbon  or  even  free  hydrogen, 
through  a  tube  or  pipe  containing  any  catalytic  or  contact  substance,  as  follows: — Oxides 
of  nitrogen,  (such,  for  instance,  as  the  gases  liberated  in  the  manufticture  of  oxalic  acid,) 
however  procured,  are  to  be  mixed  in  such  proportion  with  any  compound  of  carbon  and 
hydrogen,  or  such  mixture  of  hydrogen  and  carbonic  oxide  or  acid  as  results  from  the  con- 
tact of  the  vapor  of  water  with  ignited  carbonaceous  matters,  and  the  hydrogen  compound  or 
mixture  containing  hydrogen  may  be  in  slight  excess,  so  as  to  ensure  the  conversion  of  the 
whole  of  the  nitrogen  contained  in  the  oxide  so  employed  into  either  ammonia  or  hydro- 
cyanic acid,  which  may  be  known  by  the  absence  of  the  characteristic  red  fumes  on  allowing 
some  of  the  gaseous  matter  to  come  in  contact  with  atmospheric  air.  The  catalytic  sub- 
stance which  Messrs.  Crane  and  JuUien  prefer  is  platinum,  which  may  be  in  the  state  of 
sponge,  or  it  may  be  asbestos  coated  with  platinum.  This  catalytic  substance  is  to  be  placed 
in  a  tube,  and  heated  to  about  600°  F.,  so  as  to  increase  the  temperature  of  the  product, 
and  at  the  same  time  prevent  the  deposition  of  carbonate  of  ammonia,  which  passes  onwards 
into  a  vessel  of  the  description  well  known  and  employed  for  the  purpose  of  condensing 
carbonate  of  ammonia.  The  condenser  for  this  purpose  must  be  furnished  with  a  safety 
pipe,  to  allow  of  the  escape  of  uncondenscd  matter,  and  made  to  dip  into  a  solution  of  any 
substance  capable  of  combining  with  hydrocyanic  acid  or  ammonia  where  they  would  be 
condensed.     A  solution  of  salt  of  iron  is  preferable  for  this  purpose,  f 

Cheinical  Characters. — The  gaseous  ammonia  liberated  from  its  salts  by  lime  (in  a  man- 
ner to  be  afterwards  described)  is  a  colorless  gas  of  a  peculiar  pungent  odor.  It  is  com- 
posed, by  weight,  of  1  equivalent  of  nitrogen  and  3  of  hydrogen ;   or,  by  volume,  of  2 

*  Annales  de  Chimio  et  dc  Physique,  xliii.  1-19.  t  Phann.  Journ    xiii.  114. 


AMMONIA. 


81 


measures  of  nitrogen  and  6  of  hydrogen,  condensed  to  four ;  and  may  be  resolved  into 
these  constituent  gases  by  passing  over  spongy  platinum  heated  to  redness.  By  a  pressure 
of  6  5  atmospheres  at  50'  F.,  it  is  condensed  into  a  colorless  liciuid.  It  is  combustible,  but 
less  so  than  hydrogen,  on  account  of  the  iucombustible  nitrogen  wliich  it  contains ;  but  its 
inflammability  may  be  readily  seen  by  passing  it  into  an  argand  gas  flame  reduced  to  a 
minimum. 

Upon  this  variation  in  density  of  solutions  of  ammonia  in  proportion  to  their  strength, 
Mr.  J.  J.  Griffin  has  constructed  a  useful  instrument  called  an  Anunonia-'tnetrc.  It  is 
founded  upon  the  following  facts  : — That  mixtures  of  liquid  ammonia  with  water  possess  a 
specific  gravity  which  is  the  mean  of  the  specific  gravities  of  their  components  ;  that  in  all 
solutions  of  ammonia,  a  quantity  of  anhydrous  ammonia,  weighing  212^  grains,  which  he 
calls  a  test-atom,  displaces  300  grains  of  water,  and  reduces  the  specific  gravity  of  the  solu- 
tion to  the  extent  of  .00125  ;  and,  finally,  that  the  strongest  solution  of  ammonia  which  it 
is  possible  to  prepare  at  the  temperature  of  62'  F.,  contains  iu  an  imperial  gallon  of  solu- 
tion 100  test-atoms  of  ammonia. 

We  extract  the  following  paragraph  from  Mr.  Griffin's  paper  in  the  Transactions  of  the 
Chemical  Society,  explanatory  of  the  accompanying  Table  : — 

"  The  first  column  shows  the  specific  gravity  of  the  solutions  ;  the  second  column  the 
weight  of  an  imperial  gallon  in  pounds  and  ounces ;  the  third  column  the  percentage  of 
ammonia  by  weight ;  the  fourth  column  the  degree  of  the  solution,  as  indicated  by  the 
instrument,  corresponding  with  the  number  of  test-atoms  of  ammonia  present  in  a  gallon 
of  the  liquor ;  the  fifth  column  shows  the  number  of  grains  of  ammonia  contained  in  a  gal- 
lon ;  and  the  sixth  column  the  atomic  volume  of  the  solution,  or  that  measure  of  it  which 
contains  one  test-atom  of  ammonia.  For  instance,  one  gallon  of  liquid  ammonia,  specific 
gravity  880,  weighs  8  lbs.  128  oz.  avirdupois;  its  percentage  of  ammonia,  by  weight,  is 
33"117  ;  it  contains  96  test-atoms  of  ammonia  in  one  gallon,  and  20400.0  grains  of  ammo- 
nia in  one  gallon;  and,  lastly,  104r"16  septems  containing  one  test-atom  of  ammonia. 
Although  no  hydrometer,  however  accurately  constructed,  is  at  all  equal  to  the  Centigrade 
mode  of  chemical  testing,  yet  the  Ammonia-meter,  and  the  Table  accompanying  it,  will  be 
found  very  useful  to  the  manufacturer,  enabling  him  not  only  to  determine  the  actual 
strength  of  any  given  liquor,  but  the  precise  amount  of  dilution  necessary  to  convert  it  into 
a  liquor  of  any  other  desired  strength,  whilst  the  direct  quotation  of  the  number  of  grains 
of  real  ammonia  contained  in  a  gallon  of  solution  of  any  specific  gravity  will  enable  him  to 
judge  at  a  glance  of  the  money-value  of  any  given  sample  of  ammonia. 

Table  of  Liquid  Ammonia,  (Griffin.) 

One  Test- Atom  of  Anhydrous  Ammonia  =  NH^  weighs  212'5  grains. 

Specific  Gravity  of  Water  =  1-00000.     One  Gallon  of  Water  weighs  10  lbs.  and  contains 

10,000  Septems.     Temperature  62°  F. 


Specific  Gravity 

of  tlie  Liquid 

Ammonia. 

Weight  of  an 

Imperial  Gallon  in 

Avoirdupois  lbs. 

and  ozs. 

Percentage  of 

Ammonia  by 

Weight. 

Test-atoms 

of  Ammonia 

In  one 

Gallon. 

Grains  of 

Ammonia  in  one 

Gallon. 

Septems 

containing  one 

Test-atom  of 

Ammonia. 

lb.      oz. 

•s'zsoo 

8     12-0 

34^694 

100 

21250-9 

100-00 

•87625 

8     12-2 

34^298 

99 

21037-5 

101-01 

•87750 

8     12-4 

33-903 

98 

20825-0 

102-04 

•87875 

8     12-6 

33-509 

97 

20612-5 

103-09 

•88000 

8     12-8 

33^117 

96 

20400-0 

104^1 6 

■88125 

8     13^0 

32^725 

95 

20187-5 

105-26 

•88250 

8     13-2 

32-335 

94 

19975-0 

106-38 

•88375 

8     13-4 

31-946 

93 

19762-5 

107-53 

•88500 

8     13-6 

31-558 

92 

19550-0 

108-70 

•88625 

8     13-8 

3M72 

91 

19337-5 

109-89 

•88750 

8     14-0 

30-785 

90 

19125^0 

111-11 

•88875 

8     14^2 

30-400 

,89 

18912-5 

112^36 

•89000 

8     14-4 

30-016 

88 

18700-0 

113-64 

•89125 

8     14^6 

29-633 

87 

18487-5 

114-94 

-  -89250 

8     14-8 

29-252 

86 

18275-0 

116-28 

•89375 

8     15^0 

28^871 

85 

18062-5 

117-65 

•89500 

8     15-2 

28^492 

84 

17850-0 

119^05 

•89625 

8     15-4 

28^113 

83 

17637-5 

120-48 

•89750 

8     15^6 

27^736 

82 

17425-0 

121-95 

•89875 

8     15^8 

27^359 

81 

17212-5 

123-46 

•90000 

9       0^0 

26-984 

SO 

17000-0 

125-00 

•90125 

9       0^2 

26-610 

79 

16787-5 

126-58 

Vol.  III.— 6 


1 — — 1 

1 

82 

AMMONIA. 

Table  of  Liquid  Ammonia,  (continued.) 

Specific  Gravity 

of  the  Liquid 

AnimoDia. 

Weight  of  an 

Imperial  Gallon  in 

Avoirdupois  lbs. 

and  ozs. 

Percentage  of 

Ammonia  by 

Weight. 

Test-atoms 

of  Ammonia 

in  one 

Gallon. 

Grains  of 

Ammonia  in  one 

Gallon. 

Septems 

containing  one 

Test-atom  of 

Ammonia. 

lb.      oz. 

90250 

9       0-4 

26-237 

78 

16.575-0 

128-21 

90375 

9        0-6 

25-865 

77 

16362-5 

129-87 

90500 

9        0.8 

25-493 

76 

16150-0 

131-58 

90C25 

9       1-0 

25-123 

75 

15937-5 

133-33 

90750 

9       1-2 

24-754 

74 

15725-0 

135-13 

90875 

9       1-4 

24-386 

73 

15512-5 

136-98 

91000 

9       1-6 

24-019 

72 

15300-0 

138-99 

91125 

9       1-8 

23-653 

71 

15087-5 

140-85 

91250 

9       2-0 

23-288 

70 

14875-0 

142-86 

91375 

9       2-2 

22-924 

69 

14662-5 

144-93 

91500 

9       2-4 

22-561 

68 

14450-0 

147-06 

91C25 

9       2-6 

22-198 

67 

14237-5 

149-25 

91750 

9       2-8 

21-837 

66 

14025-0 

151-51 

91875 

9       3.0 

21-477 

65 

13812-5 

153-85 

92000 

9       3-2 

21-118 

64 

13600-0 

156-25 

92125 

9       3-4 

20-760 

63 

13387-5 

158-73 

92250 

9       3-6 

20-403 

62 

13175-0 

161-29 

92375 

9       3-8 

20-046 

61 

12962-5 

163-93 

92500 

9       4-0 

19-691 

60 

12750-0 

166-67 

92625 

9       4-2 

.      19-337 

59 

12537-5 

169-49 

92750 

9       4-4 

18-983 

58 

12325-0 

172-41 

92875 

9       4-6 

18-631 

57 

12112-5 

175-44 

93000 

9       4-8 

18-280 

56 

11900-0 

178-57 

93125 

9       5-0 

17-929 

55 

11687-5 

181-82 

93250 

9       5-2 

17-579 

54 

11475-0 

185-18 

93375 

9       5-4 

17-231 

53 

11262-5 

188-68 

93500 

9       5-6 

16-883 

52 

11050-0 

192-31 

93625 

9       5-8 

16-536 

51 

10837.5 

196-08 

93750 

9       6-0 

16-190 

50 

10625-0 

200-00 

93875 

9       6-2 

15-846 

49 

10412-5 

204-08 

94000 

9       6-4 

15-502 

48 

10200-0 

208-33 

94125 

9       6-6 

15-158 

47 

9987-5 

212-77 

94250 

9       G-8 

14-816 

46 

9775-0 

217-39 

94375 

9       7-0 

14-475 

45 

9562-5 

222-22 

94500 

9       7-2 

14-135 

44 

9350-0 

227-27 

94625 

9       7-4 

13-795 

43 

9137-5 

232-56 

94750 

9       7-6 

13-456 

42 

8925-0 

238-09 

94875 

9       7-8 

13119 

41 

8712-5 

243-90 

95000 

9       8-0 

12-782 

40 

8500-0 

250-00 

95125 

9       8-2 

12-446 

39 

8287-5 

256-41 

95250 

9       8-4 

12-111 

38 

8075-0 

263-16 

95375 

9       8-6 

11-777 

37 

7862-5 

270-27 

955O0 

9       8-8 

11-444 

86 

7650-0 

277-78 

95625 

9       9-0 

11-111 

35 

7437-5 

285-71 

95750 

9       9-2 

10-780 

34 

7225-0 

294-12 

95875 

9       9-4 

10-4490 

33 

7012-5 

303-03 

96000 

9       9-6 

10-1190 

32 

68000 

312-50 

96125 

9       9-8 

9-7901 

31 

6587-5 

322-58 

96250 

9     10-0 

9-4620 

30 

6375-0 

333.33 

96375 

9     10-2 

a- 1347 

29 

6102-5 

344-83 

96500 

9     10-4 

8-8083 

28 

5950-0 

357-14 

96625 

9     10-6 

8-4827 

27 

5737-5 

370-37 

96750 

9     10-8 

8-1580 

26 

5525-0 

384-62 

96875 

9     11-0 

7-8341 

25 

5312-5 

400-00 

97000 

9     11-2 

7-5111 

24 

5100-0 

416-67 

97125 

9     11-4 

7-1888 

23 

4887-5 

434-78 

97250 

9    lie 

6-8674 

22 

4675-0 

454-54 

97375 

9     11-8 

6-5469 

21 

4462-5 

476-19 

97500 

9     12-0 

6-2271 

20 

4260-0 

500-00 

•97625 

9     12-2 

5-9082                19          1         4037-5 

526-32 

AMMONIA. 


83 


Table  of  Liquid  Ammonia,  (continued. 


Specific  Gravity 

of  tiie  Liquid 

Ammoniji. 

Weight  of  an 

Imperial  Gallon  in 

Avoirdupois  lbs. 

and  ozs. 

Percentage  of 

Ammonia  by 

Weight. 

Test-atoms 

of  Ammonia 

in  one 

Gallon. 

Gr.ains  of 

Ammonia  in  one 

Gallon. 

Septems 

containing  one 

Test-atom  of 

Ammonia. 

•97750 

lb.      oz. 
9     12-4 

5-5901 

18 

3825-0 

555-56 

•97875 

9     12-6 

5-2728 

17 

3612-5 

688-24 

•98000 

9     ]2^8 

4-9563 

16 

3400-0 

625-00 

•98125 

9     13-0 

4-6406 

15 

3187-5 

666-67 

•98250 

9     13-2 

4^3255 

14 

2975-0 

714-29 

•98375 

9     13-4 

4^0111 

13 

2762-5 

769-23 

•98500 

9     13-6 

3^6983 

12 

2550-0 

833-33 

•98625 

9     13-8 

3^385S 

11 

2337-5 

909-09 

•98750 

9     14-0 

30741 

10 

2125-0 

1000-00 

•98875 

9     14^2 

2^7632 

9 

1912-5 

1111-10 

•99000 

9     14-4 

2^4531 

8 

1700-0 

1250-00 

•99125 

9     14^6 

2-1438 

7 

1487-5 

1428-60 

•99250 

9     14-8 

1-8352 

6 

1275-0 

1666-70 

•99375 

9     15^0 

1-5274 

5 

1062-5 

2000-00 

•99500 

9     15-2 

1-2204 

4 

850-0 

2500-00 

•99625 

9     15-4 

0^9141 

3 

637-5 

3333-30 

•99750 

9     15-6 

0^6087 

2 

425-0 

5000-00 

•99875 

9     15-8 

0-3040 

1 

212-5 

10000-00 

1-0000 

10  lbs.  Water. 

0 

Ammoniacal  gas  combines  directly  with  hydrated  acids,  forming  a  series  of  salts,  the 
constitution  of  which  is  peculiar,  and  must  be  here  briefly  discussed,  that  the  formula  here- 
after employed  in  describing  them  may  be  understood. 

These  compounds  may  be  viewed  as  direct  combinations  of  the  ammonia  with  the 
hydrated  acids  ;  thus,  the  compound  with 


Hydrochloric  acid  as  the 
Hydrosulphuric  acid    " 
Sulphuric  acid  " 

Nitric  acid  " 

Carbonic  acid  " 


Hydrochlorate,  (NH^  HCl.) 
Hydrosulphate,  (NH',  HS.) 
Hydrated  sulphate,  (NH' ;  HO,  SOI) 
Hydrated  nitrate,  (NH^ ;  HO,  N0^) 
Hydrated  carbonate,  (NH' ;  HO,  CO^). 

But  the  close  analogy  of  these  compounds,  in  all  their  properties,  to  the  corresponding 
salts  of  potash  and  soda  has  led  chemists  to  the  assumption  of  the  existence  of  a  group  of 
elements  possessing  the  characters  of  a  metal,  of  a  basyl  or  hypothetical  metallic  radical, 
called  ammonium,  (NH\)  in  these  salts  ;  which  theory  of  their  constitution  brings  out  the 
resemblance  to  the  potash  and  soda  salts  more  clearly,  thus : — 


The  chloride 

And  the  chloride 

of  potassium    contains 

-     KCl. 

of  ammonium  contains 

NH^Cl. 

—  sulphide                  " 

-    KS. 

—  sulphide           " 

NH^S. 

—  sulphate  of  potassa  " 

-    KO, 

SO'-*. 

—  sulphate  of  ammonia    - 

NH^O,  SOI 

—  nitrate           "         *' 

-    KO, 

No^ 

—  nitrate              " 

NH^O,  NOl 

—  carbonate      "         " 

-    KO, 

COl 

—  carbonate         " 

NH^O,  CO". 

Although  it  may  be  objected  to  this  view  that  the  metal  ammonium  is  not  known,  yet  a 
curious  metallic  compound  of  this  metal  with  mercury  has  been  obtained;  and,  after  all,  it 
is  by  no  means  necessary  that  the  metal  should  be  isolated,  for  already  the  existence  of 
numerous  basic  radicals  has  been  assumed  in  organic  chemistry  which  have  never  been 
isolated. 

It  is  true,  also,  that  the  oxide  of  ammonium  is  unknown,  but  substitution-products  of  it 
have  been  produced,  which  are  solid  bodies,  soluble  in  water,  exhibiting  all  the  characters 
of  potash  solution,  being  as  powerfully  caustic  and  alkaline.  In  fact,  ammonia  is  in  reality 
but  the  type  of  a  vast  number  of  compounds.  It  is  capable  of  having  its  hydrogen 
replaced  by  metals,  (as  copper,  mercury,  calcium,  &c.,)  as  well  as  by  metallic  or  basic  com- 
pound radicals,  producing  the  endless  number  of  artificial  organic  bases,  which  arc  primary, 
secondary,  or  tertiary  nitrides,  according  as  one,  two,  or  three  equivalents  of  the  ammonia 
are  replaced.  When  the  substitution  of  the  hydrogen  in  anmionia  is  effected  by  acid  radi- 
cals, the  compounds  are  called  amides. 

I'repar alio II  of- A7nvionia.  —  Ammonia,  is  obtained  by  the  decomposition  of  one  of  the 


81 


AMMONIA,  OAKBONATE  OF. 


salts  of  ammonia,  cither  the  chloride  of  ammonium,  NH*'C1,  (sal  ammoniac,)  or  the  sul- 
phate, by  a  metallic  oxide,  e.  g.  lime. 

NIPCl  +  CaO,  no  =  CaCl  -[-  NH^  -\-  2II0. 

On  the  small  scale  in  the  laboratory  the  powdered  ammoniacal  salt  is  mixed  with  slaked 
lime,  in  a  Florence  flask  or  a  small  iron  retort,  and  gently  heated ;  the  ammoniacal  gas 
being  drieil  by  passing  it  through  a  bottle  containing  lime.  Chloride  of  calcium  must  not 
be  employed  in  the  desiccation  of  ammonia,  since  the  ammonia  is  absorl>ed  by  this  salt, 

producing  a  curious  compound,  the  chloride  of  caliummonium,  N  -!  p    '-  CI,  being,  iu  fact, 

one  of  those  substitution-compounds  before  alluded  to. 

The  giiscous  ammonia  must  be  collected  over  mercury,  on  account  of  its  solubility  in 
water. 

This  operation  is  earned  out  on  the  large  scale  for  the  purpose  of  making  the  aqueous 
solution  of  ammonia,  (liquor  ammonia,  or  spirits  of  hartshorn.) 

Solution  of  Ammonia. 

Preparation. — In  preparing  the  aqueous  solution,  the  gas  is  passed  into  water  contained 
in  Woolfe's  bottles,  which  on  the  small  scale  are  of  glass,  whilst  on  the  large  scale  they  are 
made  of  earthenware. 

A  sufficiently  capacious  retort  of  iron  or  lead  should  be  employed,  which  is  provided 
with  a  movable  neck  ;  and  it  is  desirable  to  pass  the  gas  through  a  worm,  to  cool  it,  before 
it  enters  the  first  WooH'e's  bottle.  Each  of  the  series  of  Woolfe's  bottles  should  be  fur- 
nished with  a  safety-funnel  in  the  third  neck,  to  avoid  accidents  by  absorption.  The  whole 
of  the  condensing  arrangements  should  be  kept  cool  by  ice  or  cold  water. 

Properties. — In  the  London  and  in  the  Edinburgh  "  Pharmacopeia  "  two  solutions  of 
ammonia  are  directed  to  be  prepared,  the  stronger  having  the  specific  gravity  0-882,  and 
containing  about  30  per  cent,  of  ammonia  ;  the  weaker  of  specific  gravity  0-9G0,  contain- 
ing, therefore,  about  10  per  cent,  of  the  gas. 

Sometimes  the  commercial  solution  of  ammonia  is  made  by  treating  impure  ammoniacal 
salts  with  lime,  and  it  then  contains  empyreumatic  oils  ;  in  fact,  the  various  volatile  prod- 
ucts of  the  distillation  of  coal  which  are  soluble  in  or  miscible  with  water. 

Pyrrol  may  be  detected  in  ammonia  by  the  purple  color  which  it  strikes  with  an  excess 
of  nitric  or  sulphuric  acid.  If  the  residue  of  its  distillation  be  mixed  with  potash,  Picolinc 
is  detected  by  its  peculinr  odor.  Naphthaline  is  discovered  not  only  by  its  odor,  but  may 
also  be  separated  Ijy  sublimation  or  heating,  after  converting  the  ammonia  in  the  solution 
into  a  salt  by  sulphuric  or  hydrochloric  acid. — Dr.  Maclogan. 

We  imported  into  England  of  sulphate  and  liquor  of  ammonia  as  follows : — 


Ammonia,  sulphate  of. 
Ammonia,  liquor. 


1856, 
1855, 
1855, 


lbs.    23,904 

343,609 

22,400 


Since,  for  the  purpose  of  purification  on  the  large  scale,  ammonia  is  invariably  con- 
verted into  chloride  or  sulphate,  the  details  of  the  manufacture  of  the  ammoniacal  salts 
will  be  given  under  those  heads.  For  the  determination  of  ammonia,  see  Nitrogen. — H. 
M.  W. 

AMMONIA,  CARBONATE  OF.  {The  scsquicarbonate  of  commerce,  •  2NH^  3C0-, 
?no  =  NH^O,  CO-;  HO,  CO'-j-NH-'CO",  eqv.  118.)  This  salt  was  probably  known  to 
Kaymond  Lully  and  Basil  Valentine,  as  the  chief  constituent  of  putrid  urine.  The  real 
distinction  between  ammonia  and  i'js  carbonate  was  pointed  out  by  Dr.  Black. 


AMMONIA,  OAEBONATE  OF. 


85 


Carbonate  of  ammonia  is  formed  during  the  putrefaction  of  animal  substances,  and  by 
their  destructive  distillation.     Its  presence  in  rain  water  has  been  before  alluded  to. 

The  carbonate  of  ammonia  of  commerce  is  obtained  by  submitting  to  sublimation  a 
mixture  either  of  sal  ammoniac  or  sulphate  of  ammonia  with  chalk. 

This  is  generally  carried  out  in  cast-iron  retorts,  similar  in  size  and  shape  to  those  used 
in  the  manufacture  of  coal  gas.  Tiie  retorts  are  charged  through  a  door  at  one  end,  and  at 
the  other  they  communicate  with  large  square  leaden  chambers,  supported  by  a  wooden 
frame,  in  which  the  sublimed  salt  is  condensed.     Fig.  25. 

The  product  of  this  first  process  is  impure,  being  especially  discolored  by  the  presence 
of  carbonaceous  matter,  and  has  to  be  submitted  to  resublimation.  This  is  carried  out  in 
iron  pots  surmounted  by  movable  leaden  caps.     These  tops  are  either  set  in  brickwork,  and 

26 


heated  by  the  flue  of  the  retort  furnace,  or  are  placed  in  a  water-bath,  as  shown  in  fg.  26. 
In  fact,  a  temperature  not  exceeding  150°  F.  is  found  sufficient. 

The  charge  of  a  retort  consists  usually  of  about  65  lbs.  of  sulphate  of  ammonia  (or  an 
equivalent  quantity  of  the  chloride)  to  100  lbs.  of  chalk,  which  yield  about  40  lbs.  of  crude 
carbonate  of  ammonia. 

Modifications  of  the  Process. — Mr.  Laming  has  suggested  to  bring  ammonia  and  car- 
bonic acid  gases  into  mutual  contact  in  a  leaden  chamber  having  at  the  lower  part  a  layer 
of  water,  and  then  to  crystallize  the  salt  by  evaporating  this  aqueous  solution. 

He  also  proposes  to  prepare  carbonate  of  ammonia  from  the  sulphide  of  ammonium  of 
gas  liquors,  by  passing  carbonic  acid  gas  into  the  liquor,  which  carbonic  gas  is  generated  by 
heating  a  mixture  of  oxide  of  copper  and  charcoal,  in  the  proportion  of  twelve  parts  of  the 
former  to  one  of  the  latter. 

Jlr.  Ilill  has  described  his  mode  of  obtaining  sesquicarbonate  of  ammonia  from  guano. 
To  effect  this,  the  guano  is  first  mixed  with  charcoal  or  powdered  coke  ;  the  mixture  is  then 
heated,  and  the  sesquicarljonate  of  ammonia  obtained  by  sublimation.  The  pi'ocess  does 
not  appear  to  be  much  employed. 

Manufacture  of  Ammonia  from  Peat  and  Shale. — Mr.  Hills,  in  his  patent  of  August 
11th,  1846,  specified  the  following  method  of  obtaining  ammonia  from  peat: — The  peat  is 
placed  in  an  upright  furnace  and  ignited  ;  the  air  passes  through  the  bars  as  usual,  and  the 
ammonia  is  collected  by  passing  the  products  of  combustion  through  a  suitable  arrange- 
ment of  apparatus  to  effect  its  condensation.  This  plan  of  obtaining  ammonia  from  peat 
appears  to  be  precisely  similar  to  that  patented  by  Mr.  Rees  Recce,  (January  23d,  184!),) 
and  made  to  form  an  important  feature  in  the  operations  of  the  British  and  Irish  Peat  Com- 
pany. The  first  part  of  Mr.  Recce's  patent  is  for  an  invention  for  causing  peat  to  be  burned 
in  a  furnace  by  the  aid  of  a  blast,  so  as  to  obtain  inflammable  gases  and  tarry  and  otiier 
products  from  peat.  For  this  purpose,  a  blast  furnace  with  suital)le  condensing  apparatus 
is  used.  The  gases,  on  their  exit  from  the  condensing  apparatus,  may  bo  collected  for  use 
as  fuel  or  otherwise  ;  and  the  tarry  and  other  products  pass  into  a  suitable  receiver.  The 
-  tarry  products  may  be  employed  to  obtain  paraifine  and  oils  for  lubricating  machinery,  «fcc. ; 
and  the  other  products  may  be  made  available  for  evolving  aumionia,  wood  spirit,  and  otlur 
matters  by  any  of  the  existing  processes.  Dr.  Hodges,  of  Belfast,  states  that  in  his  experi- 
ments he  obtained  nearly  22 -J  lbs.  of  sulphate  of  ammonia  from  a  ton  of  peat.  Sir  Robert 
Kane,  who  was  employed  by  Government  to  institute  a  series  of  exi)erimental  researches  on 
the  products  obtainable  from  peat,  states  that  he  obtained  sulphate  of  ammonia  at  the  rate 
of  247io  lbs.  per  ton  of  peat.  Messrs.  Drew  and  Stockton  patented,  in  184('),  the  obtaining 
ammonia  from  peat  by  distillation  in  close  vessels,  as  practised  in  the  carbonization  of  wood. 


8G 


AMMONIA,  NITRATE  OF. 


It  will  thus  be  seen  that  the  peat  is  a  source  of  ammonia,  but  that  this  source  is  a  profitable 
or  econoinical  one,  in  a  commercial  point  of  view,  is  a  problem  in  process  of  solution. 

Ainiiionia  from  Sc/iist. — Another  source  of  ammonia  is  bituminous  schist,  which,  when 
submitted  to  destructive  distillation,  gives  off  an  ammoniacal  liquor  which  may  be  employed 
in  the  manufacture  of  annuoniacal  salts  by  any  of  th.e  usual  processes.  The  obtaining  of 
ammonia  from  schist  forms  part  of  a  patent  granted  to  Count  de  Uompesch,  September  4, 
ISO. 

Chemical  Composition  and  Constitution. — The  true  neutral  carbonate  of  ammonia 
(XirO,  CO^)  does  not  appear  to  exist.  The  sesquicarbonate  of  ammonia  of  the  shops  was 
found  by  Rose  to  have  the  composition  assigned  to  it  by  Mr.  Phillips,  i.  c.  it  contains 
2NIP,  300^,  2II0 ;  and  it  may  therefore  be  viewed  as  a  compound  of  the  true  bicar- 
bonate, (i.  e.  the  double  carbonate  of  ammonia  and  water,)  NH^O,  CO" ;  HO,  CO^,  with  a 
peculiar  compound  of  anhydrous  carbonic  acid  with  annnonia  itself,  (NH^,  CO'^) 

The  equation  representing  its  method  of  preparation  will  then  be, 

SNII'O,  SO'+3CaO,  CO^=CNH^O,  CO" ;  HO,  CO-+NIP,  COO+HN^O+SCaO,  SO', 
or         3NH^Cl-f  3CaO,  CO-  =  (XH^O,  CO",  HO,  CO^-fNH=,  C0-+NH^0)-|-3CaCl ; 

for  it  is  invariably  found  that  a  certain  quantity  of  water  and  ammonia  is  liberated  during 
the  distillation,  and  hence  the  anomalous  character  of  the  compound.  In  fact,  in  operating 
upon  3  equivalents  of  the  sulphate  or  chloride  of  the  3  equivalents  of  the  true  c.irbonate 
of  ammonia  (NH'O,  CO")  which  may  be  supposed  to  be  generated,  two  are  decomposed, 
one  losing  an  equivalent  of  ammonia,  the  other  an  equivalent  of  water;  of  course,  the 
ammonia  thus  liberated  is  not  lost ;  it  is  passed  into  water  to  be  saturated  with  acid,  and  thus 
again  converted  into  sulphate  or  chloride. 

Properties. — Sesquicarbonate  of  ammonia  (as  it  is  commonly  called)  is  met  with  in 
commerce  in  the  form  of  fibrous  white  translucent  cakes,  about  two  inches  thick. 

When  exposed  to  the  air  the  constituents  of  the  less  stable  compound  NH^,  CO^  are 
volatilized,  and  a  white  opaque  mass  of  the  true  bicarbonate  remains.  Hence  the  odor  of 
ammonia  always  emitted  by  the  commercial  carbonate.  Mr.  Scanlan  has  also  shown  that,  by 
treatment  with  a  small  (juantity  of  water,  the  carbonate  is  dissolved,  leaving  the  bicar- 
bonate. It  is  soluble  in  four  times  its  weight  of  cold  water,  but  boiling  water  decom- 
poses it. 

Impurities. — The  commercial  salt  is  sometimes  contaminated  with  empyreumatic  oil, 
which  is  recognized  by  its  yielding  a  brownish-colored  solution  on  treatment  with  water. 

It  may  contain  sulphate  and  chloride  of  ammonium.  For  the  recognition  of  the  pres- 
ence of  these  acids,  see  St'LPncRic  Acid. 

Sulphide  and  hyposulphite  of  ammonia  are  sometimes  present,  and  likewise  lead,  from 
the  chambers  into  which  tlie  salt  has  been  sublimed. 

Other  C(tr!jonntcs  of  Ammonia. — Besides  the  neutral  or  monocarbonate  of  ammonia 
before  alluded  to,  the  true  bicarbonate  (NH''0,  CO^ ;  HO,  CO")  and  the  sesquicarbonate  of 
the  shops.  Rose  has  described  about  a  dozen  other  definite  compounds ;  but,  for  their  de- 
scription, we  must  refer  to  Urc's  "  Dictionary  of  Chemistry." 

AMMONIA,  NITRATE  OF.  This  salt  crystallizes  in  six-sided  prisms,  being  isomor- 
phous  with  nitrate  of  potash. 

Its  composition  is  NH'O,  NO*.  It  is  incapable  of  existing  without  the  presence  of  an 
equivalent  of  water,  in  addition  to  NIP  and  NO',  If  heat  be  applied,  the  salt  is  entirely 
decomposed  into  protoxide  of  nitrogen  and  water ;  thus — 

NH^O,  NO'  =  2N0  +  4H0. 

Besides  its  use  in  the  laboratory  for  making  protoxide  of  nitrogen,  it  is  a  constituent  of 
frigorific  mixtures,  on  account  of  the  cold  which  it  jiroduces  on  dissolving  in  water. 

Lastly,  it  is  very  convenient  for  promoting  the  deflagration  of  organic  bodies,  both  its 
constituents  being  volatile  on  heating. 

AMMONIA,  SULPHATE  OF.  (NIPO,  SO'.)  This  salt  is  found  native  in  fissures  near 
volcanoes,  under  the  name  of  mossarfnine,  a.ssociatcd  with  sal  annnoniac.  It  also  forms  in 
ignited  coal-beds — as  at  Bradley,  in  Staffordshire — with  chloride  of  ammonium. 

This  salt  is  prepar(>d  by  saturating  the  solution  of  ammonia,  obtained  by  any  of  the 
processes  before  described,  (either  from  animal  refuse,  from  coal,  in  the  manufacture  of 
coal-gas,  from  guano,  or  from  any  other  source,)  with  sulphuric  acid,  and  then  evaporating 
the  solution  till  the  salt  crystallizes  out. 

Freciuently,  instead  of  adding  the  acid  to  the  ammoniacal  liquor,  the  crude  ammoniacal 
liquor  is  distilled  in  a  boiler,  cither  alone  or  with  lime,  and  the  evolved  ammonia  is  passed 
into  the  sulphuric  acid,  contained  in  a  large  tun  or  in  a  series  of  Woolfe's  bottles ;  or  a 
modification  of  Coffey's  still  may  be  used  with  advantage,  as  in  the  case  of  the  saturation 
of  hydrochloric  acid  by  ammonia. 

If  Coffey's  still  be  employed,  a  considerable  concentration  of  the  liquor  is  effected 
during  the  process  of  saturation,  which  is  subseriuently  completed  generally  in  iron  pans ; 


AMMONIA,  SULPHATE  OF. 


87 


but  great  care  has  to  be  taken  not  to  carry  the  evaporation  too  far,  to  avoid  decomposition 
of  the  sulphate  by  the  organic  matter  invariably  present,  which  reduces  it  to  the  state  of 
sulphite,  hyposulphite,  and  even  to  sulphide,  of  ammonium. 

The  salt  obtained  by  this  lirst  crystallization  is  much  purer  than  the  chloride  produced 
under  similar  circumstances,  and  one  or  two  recrystallizations  effect  its  purification  suffi- 
ciently for  all  commercial  purposes. 

It  is  on  account  of  the  greater  facility  of  purification  which  the  sulphate  affords  by  crys- 
tallization than  the  chloride  of  ammonium,  that  the  former  is  often  produced  as  a  prelimi- 
nary stage  in  the  manufacture  of  the  latter  compound,  the  purified  sulphate  being  then  con- 
verted into  sal  ammoniac  by  sublimation  with  common  salt.  The  acid  mother-liquor  left  in 
the  first  crystallization  is  returned  to  be  again  treated,  together  with  some  Jidditional  acid, 
with  a  fresh  quantity  of  ammonia. 

Frepnration.  Modifications  in  details  and  patents.- — Since  it  is  in  the  production  of 
the  sulphate  of  ammonia  that  tlie  modification  of  Coffey's  still,  called  the  ammonia  still,  is 
generally  employed,  it  may  be  well  to  introduce  here  a  detailed  account  of  its  arrangement. 

This  apparatus  is  an  upright  vessel,  divided  by  horizontal  diaphragms  or  partitions  into 
a  number  of  chambers.  It  is  proposed  to  construct  the  vessel  of  wood,  lined  with  lead,  and 
the  diaphragms  of  sheet  iroH.  Each  diaphragm  is  perforated  with  many  small  holes,  so 
regulated,,  both  with  regard  to  number  and  size,  as  to  afford,  under  some  pressure,  passage 
for  the  elastic  vapors  which  ascend,  during  the  use  of  the  apparatus,  to  make  their  exit  by 
a  pipe  opening  from  the  upper  chamber.  Fitted  to  each  diaphragm  are  several  small 
valves,  so  weighted  as  to  rise  whenever  elastic  vapors  accumulate  under  them  in  such  quan- 
tity as  to  exert  more  than  a  certain  amount  of  pressure  on  the  diaphragm.  A  pipe  also  is 
attached  to  each  diaphragm,  passing  from  about  an  inch  above  its  upper  surface  to  near  the 
bottom  of  a  cup  or  small  reservoir,  fixed  to  the  upper  surface  of  the  diaphragms  next 
underneath.  This  pipe  is  sufficiently  large  to  transmit  freely  downwards  the  whole  of  the 
liquid,  which  enters  for  distillation  at  the  upper  part  of  the  upright  vessel ;  and  the  cup  or 
reservoir,  into  which  the  pipe  dips,  forms,  when  full  of  licjuid,  a  trap  by  which  the  upward 
passage  of  elastic  vapors  by  the  pipe  is  prevented.  The  vessel  may  rest  on  a  close  cistern, 
contrived  to  receive  the  descending  liquid  as  it  leaves  the  lowest  chamber,  and  from  this 
cistern  it  may  be  run  off^,  by  a  valve  or  cock,  whenever  expedient.  The  cistern,  or  in  its 
absence  the  lowest  chamber,  contains  the  orifice  of  a  pipe  which  supplies  the  steam  for 
working  the  apparatus.  The  exact  number  of  chambers  into  which  the  upright  vessel  is 
divided  is  not  of  essential  importance  ;  but  the  quantity  of  liquid  and  the  surface  of  each 
diaphragm  being  given,  the  distillation,  within  certain  limits,  will  be  more  complete  the 
greater  the  number  of  chambers  used  in  the  process.  The  liquid  undergoing  distillation  in 
this  apparatus  necessarily  covers  the  upper  surface  of  eacli  diaphragm  to  the  depth  of  about 
an  inch,  being  prevented  from  passing  downward  through  the  small  perforations  by  the  up- 
ward pressure  of  the  rising  steam  and  other  elastic  vapors ;  and,  on  the  other  hand,  the 
steam  being  prevented,  by  the  traps,  from  passing  upwards  by  the  pipes,  is  forced  to  ascend 
by  the  perforations  in  the  diaphragms ;  so  that  the  liquid  lying  on  them  becomes  heated, 
and  in  consequence  gives  off"  its  volatile  matters.  When  the  ammoniacal  liquor  accumu- 
lates on  one  of  the  diaphragms  to  the  depth  of  an  inch,  it  flows  over  one  of  the  short  pipes 
into  the  trap  below,  and  overflows  into  the  next  diaphragm,  and  so  on.     See  Distillation. 

The  management  of  the  apparatus  varies  in  some  measure  with  the  form  in  which  it  is 
desirable  to  obtain  the  ammonia.  When  the  ammonia  is  required  to  leave  the  upper  cham- 
ber in  the  form  of  gas,  either  pure  or  impure,  it  is  necessary  that  the  steam  which  ascends 
and  the  current  of  ammoniacal  liquid  which  descends,  should  be  in  such  relative  propor- 
tions that  the  latter  remain  at  or  near  the  atmospheric  temperature  during  its  passage 
through  some  of  the  upper  chambers,  becoming  progressively  hotter  as  it  descends,  until  it 
reaches  the  boiling  temperature ;  in  which  state  it  passes  through  the  lower  chambers,  either 
to  make  its  escape,  or  to  enter  a  cistern  provided  to  receive  it,  and  in  which  it  may  for 
some  time  be  maintained  at  a  boiling  heat.  On  the  contrary,  if  the  ammonia,  either  pure 
or  impure,  be  required  to  leave  the  upper  chamber  in  combination  with  the  vapor  of  water, 
tlie  su[>ply  of  steam  entering  below  must  bear  such  proportion  to  that  of  the  ammoniacal 
liquid  supplied  above,  that  the  hitter  may  be  at  a  boiling  temperature  in  tlic  upper  part  of 
the  apparatus.* 

The  use  of  this  apparatus  has  been  patented  in  the  name  of  Mr.  W.  E.  Newton,  Nov. 
9,  1811. 

iMr.  Hill's  process,  patented  Oct.  19,  1848,  for  concentrating  ammoniacal  solutions,  by 
causing  them  to  descend  through  a  tower  of  coke  through  which  steam  is  ascending,  is,  in 
fact,  nothing  more  than  a  rough  mode  of  carrying  out  the  same  principle  which  is  more 
effectually  and  elegantly  performed  by  the  modification  of  Coffey's  still  above  described. 
The  concentrated  ammonia  liquor  is  then  treated  with  acid  and  evaporated  in  the  usual 
way. 

Mr.  Wilson  has  patented,  Dec.  T,  1850,  another  method  of  saturating  the  ammonia  with 

♦  Pliarm.  Joiiriuil,  xiii.  ('4. 


88  AMMONIUM. 

the  acid  by  passing  tlie  crude  ammonia  vapor,  obtained  by  heating  the  ammoniacal  lifnior 
of  the  gas-works,  in  at  the  bottom  of  a  liigh  tower  filled  with  coke,  whilst  the  suliiluuic 
acid  descends  in  a  continuous  current  from  the  top  ;  in  this  manner  the  acid  and  ammonia 
are  exposed  to  each  other  over  a  greatly  extended  suri'ace. 

Dr.  Kichardson  (patent,  Jan.  2(i,  1850)  mixes  the  crude  ammonia  liquors  with  sulphate 
of  magnesia,  then  evaporates  the  solution,  and  submits  the  double  sulphate  of  magnesia 
and  ammonia,  which  separates,  to  sublimation  ;  but  it  would  not  appear  that  any  great 
advantage  is  derived  from  proceeding  in  this  way,  either  pecuniary  or  otherwise. 

.Mr.  Laming  i)asses  sulphurous  acid  through  the  gas  liciuor,  and  finally  oxidizes  the  sul- 
phite thus  obtained  to  the  state  of  sulphate,  by  exposure  to  the  air.  (Patent,  Aug.  12, 
1S52.) 

Michiel's  mode  of  obtaining  sulphate  of  ammonia,  patented  April  SO,  1850,  is  as  fol- 
lows :  — The  ammoniacal  liquors  of  the  gas-works  are  combined  with  sulphate  and  oxide  of 
lead,  which  is  obtained  and  jjrepared  in  the  following  way  : — Sulphuret  of  lead  in  its  natu- 
ral state  is  taken  and  reduced  to  small  fragments  by  any  convenient  crushing  apparatus.  It 
is  then  submitted  to  a  roasting  process,  in  a  suitably  arranged  reverberatory  furnace  of  the 
following  construction  : — The  furnace  is  formed  of  two  shelves,  or  rather  the  bottom  of  the 
furnace  and  one  shelf,  and  there  is  a  communication  from  *lie  lower  to  the  upper.  The 
galena  or  sulphuret  of  lead,  previously  ground,  is  then  spread  over  the  surface  ol'.the  upper 
shelf,  to  a  thickness  of  about  2  or  2^  inches,  and  there  it  is  submitted  to  the  heat  of  the 
furnace.  It  remains  thus  for  about  two  hours,  at  which  time  it  is  drawn  off  the  upper  shelf 
and  spread  over  the  lower  shelf  or  bottom  of  the  furnace,  where  it  is  exposed  to  a  greater 
heat  for  a  certain  time,  during  which  it  is  well  stirred,  for  the  purpose  of  exposing  all  the 
parts  equally  to  the  action  of  the  heat,  and  at  the  same  time  the  fusion  of  any  portion  of  it 
is  prevented.  By  this  process  the  sulphuret  of  lead  becomes  converted  partly  into  sulphate 
and  partly  into  oxide  of  lead.  This  product  of  sulphate  and  oxide  of  lead  is  to  be  crushed 
by  any  ordinary  means,  and  reduced  to  about  the  same  degree  of  fineness  as  coarse  sand. 
It  is  now  to  be  combined  with  the  ammoniacal  liquors,  when  sulphate  of  ammonia  and  sul- 
phuret and  carbonate  of  lead  will  be  produced. 

The  sulphate  of  ammonia  is  separated  by  treatment  with  water,  and  the  residuary  mix- 
ture of  sulphide  and  carbonate  of  lead  is  used  for  the  manufacture  of  lead  compounds. 

Properties. — The  sulphate  of  ammonia  obtained  by  either  of  the  methods  above  de- 
scribed is  a  colorless  salt,  containing,  according  to  Mitschcrlich,  one  equivalent  of  water  of 
crystallization.     It  is  isomorphous  with  sulphate  of  potash. 

It  deliquesces  by  exposure  to  the  air  ;  1  part  dissolves  in  2  parts  of  cold  water,  and  1 
of  boihng  water.  It  fuses  at  140"  C,  (284°  F.,)  but  at  280"  C.  (536"  F.)  it  is  decomposed, 
being  volatilized  in  the  form  of  free  ammonia,  sulphite,  water,  and  nitrogen. 

For  the  other  sulphates — the  sulphites  and  those  salts  which  are  but  little  used  in  the 
arts  and  manufactures — we  refer  to  the  "  Dictionary  of  Chemistry." 

Usea. — The  chief  consumption  of  ammoniacal  salts  in  the  arts  is  in  the  form  of  sal 
ammoniac,  the  sulphate  of  ammonia  being  principally  used  as  a  material  for  the  manufac- 
ture of  the  chloride  of  ammonium.  It  may,  however,  be  employed  directly  in  making 
ammonia-alum,  or  in  the  production  of  free  ammonia  by  treatment  with  lime. 

AMMOXIUM.  (NIP.)  The  radical  supposed  to  exist  in  the  various  salts  of  ammonia. 
Thus  Niro  is  the  oxide,  NirC'I  the  chloride,  of  ammonium.  Ammonium  constitutes  one 
of  the  best  established  chemical  tvpes.     See  Formula,  Chemical. — C.  G.  W. 

AMMONIUM,  CHLORIDE  OF.  This  salt  is  formed  in  the  solid  state  by  bringing  in 
contact  its  two  gaseous  constituents,  hydrochloric  acid  and  ammonia.  The  gases  combine 
with  such  force  as  to  generate,  not  only  heat,  but  sometimes  even  light.  It  may  also  be 
prepared  by  mixing  the  aqueous  solutions  of  these  gases,  and  evaporating  till  crystallization 
takes  place. 

When  ammoniacal  gas  is  brought  into  contact  with  dry  chlorine,  a  violent  reaction 
ensues,  attended  t)y  the  evolution  of  heat  and  even  light.  The  chlorine  combines  with  the 
hydrogen  to  produce  hydrochloric  acid,  which  unites  with  the  remainder  of  the  ammonia, 
forming  chloride  of  ammonium,  the  nitrogen  being  liberated.  The  same  reaction  takes 
place  on  passing  chlorine  gas  into  the  saturated  aqueous  solution  of  ammonia. 

Mdnufncture  of  Sal  Anunoninc  from  Gas  ]A<pior. — l?y  far  the  largest  quantity  of  the 
ammoniacal  salts  now  met  with  in  commerce  is  prepared  from  "  gas  liquor,"  tlie  quantity  of 
which  annually  produced  in  the  metropolis  alone  is  quite  extraordinary — one  of  the  London 
gas  works  producing  in  one  year  224,800  gallons  of  gas  liquor,  l)y  the  distillation  of  51,100 
tons  of  coal ;  and  the  total  consumption  of  coal  in  London  for  gas  making  is  estimated  at 
about  840,000  tons. 

The  principle  of  the  conversion  of  the  nitrogen  of  coal  into  ammonia  by  destructive 
distillation,  as  in  the  manufacture  of  coal  gas,  will  be  found  described  in  connection  with 
the  processes  of  gas  manufacture  and  the  products  produced  by  the  destructive  distillation 
of  coal. 

In  the  purification  of  the  coal  gas,  the  bodies  soluble  in  water  are  all  contained  in  the 


AMMONIUM,  CHLORIDE  OF. 


8 'J 


"  iras  liquor,"  (see  Coal  Gas,)  together  with  a  certain  quantity  of  tarry  matter.  The  am- 
monia is  chiefly  present  in  tlie  form  of  carbonate,  together  with  certain  quantities  of  chlo- 
ride, sulphide,  cyanide,  and  sulphocyanide  of  ammonium,  as  well  as  the  salts  of  the  com- 
pound ammonias. 

For  the  purpose  of  preparing  the  chloride,  if  hydrochloric  acid  be  not  too  costly,  the 
liquor  is  saturated  with  hydrochloric  acid — the  solution  evaporated  to  cause  the  salt  to 
crystallize   and  then,  finally,  the  crude  sal  ammoniac  is  purified  by  sublimation. 

Before  treatment  with  the  acid,  the  liquor  is  frequently  distilled. 

This  is  generally  effected  in  a  wrought-iron  boiler,  the  liquors  passing  into  a  modification 
of  the  Coffey's  still,  by  which  the  solution  of  ammonia  is  obtained  freer  from  tar  and  more 
concentrated. 

T/ie  Saturation  of  the  Ammoniacal  Liquor  with  the  acid  is  generally  effected  by  allow- 
in''  the  acid  to  flow,  from  a  large  leaden  vessel  in  which  it  is  held,  into  an  underground 

27 


tank  ( fid.  27)  containing  the  liquor,  which  is  furnished  with  an  exit  tube  passing  into  a 
chimney,  to  carry  off  the  sulphuretted  hydrogen  and  other  offensive  gases  which  are  disen- 
gaged. 

Or,  in  other  works,  the  gas  liquor  is  put  into  large  tuns,  and  the  acid  lifted  in  gutta- 
percha carboys  by  cranes,  thrown  into  the  liquor  and  stirred  with  it  by  means  of  an  agi- 
tator ;  the  offensive  gases  being  in  this  case  made  to  traverse  the  fire  of  the  steam-engine. 

Sometimes  the  vapors  produced  in  the  distillation  of  the  crude  gas  liquor  are  passed  in 
at  the  lower  extremity  of  a  column  filled  with  coke,  down  which  the  acid  trickles. 

The  Evaporation  of  t/ic  crude  Saline  Solution  is  generally  performed  in  square  or  rec- 
tangular cast-iron  vats,  capable  of  holding  from  800  to  1,500  gallons.  They  are  encased  in 
brickwork,  the  heat  being  applied  by  a  fire,  the  flue  of  which  takes  a  sinuous  course  beneath 
the  lining  of  brickwork  on  which  the  pan  rests,  a.s  shown  in  /rV/.  28. 

When  the  liquor  is  evaporated  to  a  specific  gravity  of  1-25,  it  is  transferred  to  the  crys- 
tallizing pans ;  but  during  the  processes  of  concentration  a  considerable  quantity  of  tar 
separates  on  the  surface,  which  must  be  removed,  from  time  to  time,  by  skimming,  since  it 
seriously  impedes  evaporation. 

The  cri/stallisation,  which  takes  place  on  cooling,  is  performed  in  circular  tubs,  from  7 
to  8  feet  wide,  and  2  to  3  deep,  which  arc  generally  imbedded  entirely  or  partially  in  the 
ground.  To  prevent  the  formation  of  large  crystals,  which  would  be  inconvenient  in  the 
subsequent  process  of  sublimation,  the  lifjuor  is  agitated  from  time  to  time.  The  crude 
mass  oljtained,  which  is  contaminated  with  tarry  matter,  free  acid  and  water,  is  next  dried, 
by  gently  heating  it  on  a  cast-iron  plate  under  a  dome.  The  grayish-white  mass  renuxining 
is  now  ready  to  be  transferred  to  the  sul)limers. 

The  method  of  snftUmatirni  generally  adopted  in  this  country  consists  in  beating 
down  into  the  metal  pots,  shown  in  fi;j-  -">  the  charge  of  dry  coarsely  crj^stallizcd  sal  am- 
moniac. These  pots  are  heated  from  below  and  by  flues  round  the  siiies.  The  l)ody  of  the 
subliming  vessel  is  of  cast-iron,  and  the  lid  usually  of  lead,  or,  less  frequently,  iron.  There 
is  a  small  hole  at  the  top,  to  permit  the  escape  of  steam  ;  and  great  attention  is  requisite  in 
the  management  of  the  heat,  for  if  it  be  applied  too  rapidly  a  large  quantity  of  sal  ammoniac 


90 


AMMOiflUM,  CHLORIDE  OF. 


is  carried  off  with  the  steam,  or  even  the  whole  apparatus  may  be  blown  up  ;  whilst,  if  the 
temperature  be  too  low,  the  cake  of  sal  ammoniac  is  apt  to  be  soft  and  yellow. 


The  sublimation  is  never  continued  until  the  whole  of  the  salt  has  been  volatilized,  since 
the  heat  required  would  decompose  the  carbonaceous  impurities,  and  they,  emitting  volatile 
oily  hydrocai'bons,  diminish  the  purity  of  the  product.  In  consequence  of  this  incomplete 
subUmation,  a  conical  mass  (shown  in  Jig.  29)  is  left  behind,  called  the  "  yolk."     After 

29 


cooling,  the  dome  of  the  pot  is  taken  off,  and  the  attached  cake  carefully  removed.  This 
cake,  which  is  from  3  to  5  inclics  thick,  is  nearly  pure,  only  requiring  a  little  scraping, 
whore  it  was  in  contact  with  tlie  doiuc,  to  fit  it  for  the  market. 

Modifications  of  the  Process. — If,  as  is  often  the  case,  sulphuric  acid  is  cheaper  or  more 
accessible  than  hydrochloric,  tlie  gas  liquor  is  neutralized  with  sulphuric  acid,  and  then  the 
sulphate  of  ammonia  thus  obtained  is  sublimed  with  common  salt,  {chloride  of  sodium,)  and 
thus  converted  into  sal  ammoniac. 

NIPO  SO'  +  NaCI  =  NirCl+NaOSO^ 

Mr.  Croll  has  taken  out  a  patent  for  converting  crude  ammonia  into  the  chloride,  by 
passing  the  vapors  evolved  in  the  first  distillation  through  the  crude  chloride  of  manganese, 
obtained,  as  a  l)ye  product  in  the  preparation  of  chlorine,  for  the  manufacture  of  chloride  of 
lime  :  crude  chloride  of  iron  may  be  used  in  the  same  wav. 


AMMONIUM,  CHLORIDE  OF.  91 

Mr.  Laming  patented  in  July,  1843,  the  substitution  of  a  solution  of  chloride  of  calcium 
for  treating  the  crude  gas  liiiuor,  instead  of  the  mineral  acids.  Mr.  Hills,  August,  1846, 
proposed  chloride  of  magnesium  for  use  in  the  same  way ;  and  several  other  patents  have 
been  taken  out  by  both  these  gentlemen,  for  the  use  of  various  salts  in  this  way. 

Manufacture  of  Hal  Ammoniac  from  Guano. — Mr.  Young  took  out  a  patent,  November 
11th,  1841,  in  which  he  describes  his  method  of  obtaining  ammonia  and  its  salts  from  guano. 
He  fills  a  retort,  placed  vertically,  with  a  mixture  of  two  parts  by  weight  of  guano,  and  one 
part  by  weight  of  hydrate  of  lime.  These  substances  are  thoroughly  mixed  by  giving  a 
reciprocating  motion  to  the  agitator  placed  in  the  retort ;  a  moderate  degree  of  heat  is  then 
applied,  which  is  gradually  increased  until  the  bottom  of  the  retort  becomes  red-hot.  The 
ammoniacal  gas  thus  given  off  is  absorbed  by  water  in  a  condenser,  whilst  other  gases,  which 
are  given  off  at  the  same  time,  being  insoluble  in  water,  pass  off.  Solutions  of  carbonate, 
bicarbonate,  or  sesquicarbonate  of  ammonia  are  produced,  by  filling  the  condenser  with  a 
solution  of  ammonia,  and  passing  carbonic  acid  through  it.  A  solution  of  chloride  of  am- 
monium or  sulphate  of  ammonia,  is  obtained  by  filling  the  condenser  with  diluted  hydro- 
chloric or  sulphuric  acid,  and  passing  the  ammonia  through  it  as  it  issues  from  the  retort. 

Dr.  Wilton  Turner  obtained  a  patent,  March  11th,  1844,  for  obtaining  salts  of  ammonia 
from  guano.  The  following  is  his  method  of  obtaining  chloride  of  ammonium  in  conjunction 
with  cyanogen  compounds  : — The  guano  is  subjected  to  destructive  distillation  in  close  ves- 
sels, at  a  low  red  heat  during  the  greater  part  of  the  operation  ;  but  this  temperature  is  in- 
creased towards  the  end.  The  products  of  distillation  are  collected  in  a  series  of  Woolfe's 
bottles,  by  means  of  which  the  gases  evolved  during  the  operation  may  be  made  to  pass  two 
or  three  times  through  water,  before  escaping  into  the  air.  These  products  consist  of  car- 
bonate of  ammonia,  hydrocyanic  acid,  and  carburetted  hydrogen,  the  first  two  of  which  are 
rapidly  absorbed  by  the  water,  with  the  formation  of  a  strong  solution  of  cyanide  of  am- 
monium and  carljonate  of  ammonia.  After  the  ammoniacal  solution  has  been  removed  from 
the  Woolfe's  apparatus,  a  solution  of  protochloride  of  iron  is  added  to  it,  in  such  quantities 
as  will  yield  sufficient  iron  to  convert  the  latter  into  Prussian  blue,  which  is  formed  on  the 
addition  of  hydrochloric  acid  in  sufficient  quantity  to  neutralize  the  free  ammonia ;  the 
precipitate  thus  formed  is  now  allowed  to  subside,  and  is  carefully  separated  from  the  solu- 
tion, and  by  being  boiled  with  a  solution  of  potash  or  soda,  will  yielcf  the  ferrocyanide  of 
the  alkali,  which  is  obtained  by  crystallizing  in  the  usual  way.  The  solution  (after  the 
removal  of  the  precipitate)  should  be  freed  from  any  excess  of  iron  it  may  contain,  by  the 
careful  addition  of  a  fresh  portion  of  tlie  ammoniacal  liquor,  by  which  means  the  oxide  of 
iron  will  be  precipitated,  and  a  neutral  solution  of  ammonia  obtained.  When  the  precipi- 
tated oxide  and  cyanide  of  iron  have  subsided,  the  solution  of  chloride  of  ammonium  is 
drawn  off  by  a  syphon,  and  the  sal  ammoniac  obtained  from  it  by  the  usual  processes ;  the 
oxide  of  iron  is  added  to  the  ammoniacal  solution  next  operated  upon. 

If  sulphate  of  iron  and  sulphuric  acid  are  used,  sulphate  of  ammonia  is  the  ammoniacal 
salt  produced,  the  chemical  changes  and  operations  being  similar  to  the  above. 

Since  the  greater  part  of  the  nitrogen  present  in  guano  exists  in  the  state  of  ammoniacal 
salts,  which  are  decomposed  at  a  red  heat,  nearly  the  whole  of  the  ammonia  which  it  is 
capable  of  yielding  is  obtained  by  this  method  ;  still  there  cannot  be  a  doubt  that  the  con- 
version of  the  urea,  uric  acid,  and  otiier  nitrogenized  organic  bodies  into  ammonia,  is 
greatly  facilitated  by  mixing  the  guano  with  lime  before  heating  it,  as  in  Mr.  Young's 
process. 

Manufacture  of  Sal  Ammoniac  from  Urine. — The  urea  in  the  urine  of  man  and  other 
animals  is  extremely  liable  to  undergo  a  fermentative  decomposition  in  the  presence  of  the 
putrefiable  nitrogenous  matters  alwa_ys  present  in  this  excrement,  by  v/hich  it  is  converted 
into  carbonate  of  ammonia. 

By  treating  stale  urine  with  hyhroehloric  acid,  sal  ammoniac  separates  on  evaporation. 

Properties. — Chloride  of  ammonium  (or  sal  ammoniac)  usually  occurs  in  commerce  in 
fil)rou3  masses  of  the  form  of  large  hemispherical  cakes  with  a  round  hole  in  the  centre, 
having,  in  fact,  the  shape  of  the  domes  in  which  it  has  been  sublimed.  By  slowly  cva])orat- 
ing  its  aqueous  solution,  the  salt  may  occasionally  be  obtained  in  cakes  nearly  an  inch  in 
height ;  but  it  generally  forms  feathery  crystals,  which  are  composed  of  rows  of  minute  oc- 
tahedra,  attached  by  their  extremities.  Its  specific  gravity  is  1-4;"),  and  by  heating  it 
sublimes  without  undergoing  fusion.  It  has  a  sharp  and  acrid  taste,  and  one  part  dissolves 
in  2-7"2  parts  of  hot,  or  in  an  ecjual  weight  of  cold  water. 

It  is  recognized  by  its  being  completely  volatile  on  heating,  giving  a  white  curdy  preci- 
pitate of  chloride  of  silver  on  the  addition  of  nitrate  of  silver  to  its  acjueous  solution,  and  by 
the  copious  evolution  of  ammonia  on  mixing  it  with  lime,  as  well  as  the  production  of  the 
yellow  precipitate  of  the  doul)le  chloride  of  ammonium  and  patinum  (NIPC,  PaCl-)  on 
the  addition  of  bichloride  of  platinum. 

Impurities. — In  the  manufacture  of  chloride  of  ammonium,  if  the  purification  of  the 
liquor  be  not  effected  before  crystallizing  the  salt,  some  traces  of  protochloride  of  iron  are 
generally  present,  and    frequently  a  considerable    proportion.      Even  when  the  salt   is 


92  AMMONIUM,  SULPHIDES  OF. 

sublimed  the  chloride  of  iron  is  volatilized  together  with  the  chloride  of  ammoniura,  and 
appears  to  exist  in  the  salt  in  the  form  of  a  double  compound  (probably  of  Fe,  CI  J\H''C1, 
analo"-ou3  to  the  compounds  which  chloride  of  ammonium  forms  with  zinc  and  tin)  140  ; 
and  this  not  only  in  the  brown  seams  of  the  cake,  but  likewise  in  the  colorless  portion. 
This  accounts  for  the  observation  so  often  made  in  the  laboratory,  that  a  solution  of  sal 
annnoniac,  which,  when  recently  prepared,  was  perfectly  transparent  and  colorless,  becomes 
gradually  red  from  the  peroxidation  of  the  iron  and  its  precipitation  in  the  form  of  sesqui- 
oxide. 

It  is  in  consequence  of  the  existence  of  the  iron  in  the  state  of  this  double  salt,  that 
Wurtz  found  that  chloride  of  ammonium  containing  iron  in  this  form  gave  no  indications 
of  its  presence  by  the  tisual  re-agents  until  after  the  addition  of  nitric  acid  ;  and  it  is  curious 
that  there  likewise  exists  a  red  compound  of  this  class  in  which  the  iron  exists  in  the  state 
of  perchloride  similarly  marked,  in  fact  as  KH''  CI  Fe'^Cl'. 

A  vcrv  simple  method  of  removing  the  iron,  suggested  by  Mr.  Brewer,  consists  in  pass- 
ing a  fewbubblcs  of  chlorine  gas  through  the  hot  concentrated  solution  of  the  salt,  by  which 
the  i)rotochloridc  of  iron  is  converted  into  the  perchloride. 

2Fe  CI  +  CI  =  Fe'Cl'. 

The  free  ammonia  always  present  in  the  solution  decomposes  this  perchloride  with  pre- 
cipitation of  sesquioxide,  and  formation  of  an  additional  quantity  of  sal  ammoniac. 

Fe-Cl'  +  3NH^0  =  Fe'O^  +  3NH*C1. 

The  sesquioxide  of  iron,  which  is  of  course  present  in  the  form  of  a  brown  hydrate,  is 
fdtcrcd  oil"  or  separated  by  dccantation,  and  a  perfectly  pure  solution  is  obtained. 

The  only  precaution  necessary  is  to  avoid  passing  more  chlorine  than  is  requisite  to 
peroxidize  the  iron,  since  the  ammonia  salt  itself  will  be  decomposed  with  evolution  of 
nitrogen,  and  the  dangerously  explosive  body,  chloride  of  nitrogen,  may  result  from  the 
union  of  the  liberated  nitrogen  with  chlorine. 

l^xrs. — The  most  important  use  of  sal  ammoniac  in  the  arts  is  in  joining  iron  and 
other  metals,  in  tinning,  &c.  It  is  also  extensively  used  in  the  manufacture  of  ammonia- 
alum,  which  is  now  largely  employed  in  the  manufacture  of  mordants  instead  of  potash- 
alum.     A  considerable  quantity  is  also  consumed  in  pharmacy. 

Sal  ammoniac  is  one  of  those  salts  which  possess,  in  a  high  degree,  the  property  of 
producing  cold  whilst  dissolving  in  water ;  it  is,  therefore,  a  common  constituent  of  frigorific 
mixtures.     See  Freezing. 

AMMONIUM,  SULPHIDES  OF.  When  sulphuretted  hydrogen  gas  is  passed  into  a  solu- 
tion of  ammonia  in  excess,  it  is  converted  into  the  double  sulphide  of  ammonium  and  hy- 
drogen— or,  as  it  is  frequently  called,  the  hydrosulphate  of  sulphide  of  ammonium — 
Nh'^S,  IIS. 

This  solution  is  extensively  employed  as  a  re-ngent  in  the  chemical  laboratory,  for  the 
separation  of  those  metals  the  .'sulphides  of  which  are  soluble  in  acids — viz.,  nickel,  cobalt, 
manganese,  zinc,  and  iron,  which  are  precipitated  by  this  re-agent  in  alkaline  solutions. 

By  exposure  to  the  air,  the  hydrosulphuric  acid  which  it  contains  is  decomposed,  the 
hydrogen  being  oxidized  and  converted  into  water,  whilst  the  liberated  sulphur  is  dissolved 
by  the  sulphide  of  ammonium,  forming  the  bisulphide,  or  even  higher  sulphide. 

This  solution  of  the  polysulphide  of  ammonium  is  a  valuable  re-agent  for  dissolving  the 
sulphides  of  certain  metals,  such  as  tin,  antimony,  and  arsenic,  the  sulphides  of  which  play 
the  part  of  acids  and  form  salts  with  the  sulphide  of  ammonium. 

By  this  deportment  with  sulphide  of  ammonium,  these  metals  are  separated  both  on  the 
small  scale  in  the  laboratory  and  also  on  the  large  scale,  from  the  sulphides  of  those  metals 
— such  as  lead,  copper,  mercury,  &c. — the  sulphides  of  which  are  insoluble  in  sulphide  of 
ammonium. 

The  higher  sulphides,  viz.,  the  tcrsulphide,  Nn''S',  and  the  pcntasulphide,  NH^S", — are 
bodies  of  purely  scientific  interest.  They  are  obtained  by  .distilling  the  corresponding 
sulphides  of  potassium  with  sal  ammoniac. 

All  the  sulphides  of  ammonium  arc  solul)lc  in  water  without  decomposition. 
Ammonia  combines  with  all  the  other  inorganic  and  organic  acids,  the  name  of  which 
is  "legion;"  but  for  an  accoiuit  of  these  bodies  we  must  refer  to  the   "Dictionary  of 
Chemistrv,"  as  they  have  but  few  a]>plicati()ns  in  the  arts  and  manufactures. 

AMORPHOUS.  This  term  may  be  regarded  as  the  opposite  of  crystalline.  Some 
elements  exist  in  both  the  crystalline  and  the  amorphous  states,  as  carbon,  which  is  amor- 
phous in  charcoal,  but  crystalline  in  the  diamond. 

The  peculiarities  which  give  rise  to  these  conditions — evidently  depending  upon  mole- 
cular forces  which  have  not  yet  been  defined — present  one  of  the  most  fertile  fields  for  study 
in  the  range  of  modern  science. 

AMYGDALIXE.  (C"  II"'  NO"  -f-  6110.)  A  peculiar  substance,  existing  ready  formed 
in  bitter  almonds,  the  leaves  of  the  cherry  laurel,  the  kernels  of  the  plum,  cherry,  peach, 


ANCHOR.  93 

and  the  leaves  and  bark  of  Primus  padus,  and  in  the  young  sprouts  of  the  F.  domestica. 
It  is  also  found  in  the  sprouts  of  several  species  of  Sorbm,  such  as  S.  aucuparia,  S.  tormi- 
nalia,  and  others  of  the  same  order.  To  prepare  it,  the  bitter  almonds  are  subjected  to 
strong  pressure  between  hot  plates  of  metal.  This  has  the  effect  of  removing  the  bland  oil 
known  in  commerce  as  almond  oil.  The  residue,  when  powdered,  forms  almond  meal.  To 
obtain  amygdaline  from  the  meal,  the  latter  is  extracted  with  boiling  alcohol  of  90  or  95 
per  cent.  The  tincture  is  to  be  passed  through  a  cloth,  and  the  residue  pressed,  to  obtain 
the  fluid  mechanically  adherent  to  it.  The  liquids  will  be  milkj',  owing  to  the  presence  of 
some  of  the  oil.  On  keeping  the  fluid  for  a  few  hours,  it  may  be  separated  by  pouring  off, 
or  by  means  of  a  funnel,  and  so  obtained  clear.  The  alcohol  is  now  to  be  removed  by  dis- 
tillation, the  latter  being  continued  until  five-sixths  have  come  over.  The  fluid  in  the 
retort,  when  cold,  is  to  have  the  amygdaline  precipitated  from  it  by  the  addition  of  half  its 
volume  of  ether.  The  crystals  are  to  be  pressed  between  folds  of  filtering  paper,  and  re- 
crystallized  from  concentrated  boiling  alcohol.  As  thus  prepared  it  forms  pearly  scales  very 
soluble  in  hot  alcohol,  but  sparingly  when  cold  ;  it  is  insoluble  in  ether,  but  water  dissolves 
it  readily  and  in  large  quantity.  The  crystals  contain  six  atoms  of  water  of  crystallization. 
Most  persons  engaged  in  chemical  operations  have  noticed,  when  using  almond  meal  for  the 
purpose  of  luting,  that,  before  being  moistened  with  water,  it  has  little  odor,  and  what  it 
has  is  of  an  oily  kind ;  but,  after  moistening,  it  soon  acquires  the  powerful  and  pleasant 
perfume  of  bitter  almond  oil.  This  arises  from  a  singular  reaction  taking  place  between  the 
amygdaline  and  the  vegetable  albumen  or  emulsine.  The  latter  merely  acts  as  a  ferment, 
and  its  elements  in  no  way  enter  into  the  products  formed.  The  decomposition,  in  fact, 
takes  place  between  one  equivalent  of  amygdaline  and  four  equivalents  of  water,  the  prod- 
uct being  one  equivalent  of  bitter  almond  oil,  two  equivalents  of  grape  sugar,  and  one  of 
prussic  acid.     Or,  represented  in  symbols  :  — ^ 

C^"  H"  NO"    4-    4H0  =  C"  H"  0'   +   C"  HN    +    2C'^  IP"  0'-. 

Amygdaline.  Bitter-almond      Prussic  Grape  sugar, 

oil.  acid. 

In  preparing  amygdaline,  some  chemists  add  water  to  the  residue  of  the  distillation  of 
the  tincture,  and  then  yeast,  in  order  to  remove  the  sugar  present,  by  fermentation,  previous 
to  precipitating  with  ether ;  the  process  thus  becomes  much  more  complex,  because  it  is 
necessary  to  filter  the  fermented  liquid,  and  concentrate  it  again  by  evaporation,  before 
precipitating  out  the  amygdaline. 

Tlie  proof  that  the  decomposition  which  is  experienced  by  the  bitter  almond  cake,  when 
digested  with  water,  is  owing  to  the  presence  of  the  two  principles  mentioned,  rests  upon 
the  following  considerations :  If  the  marc,  or  pressed  residue  of  the  bitter  almond,  be 
treated  with  boiling  water,  the  emulsine — or  vegetable  albumen — will  become  coagulated, 
and  incapable  of  inducing  the  decomposition  of  the  amygdaline.  Moreover,  if  the  latter  be 
removed  from  the  marc  with  hot  alcohol  previous  to  operating  in  the  usual  manner  for  the 
extraction  of  the  essential  oil,  not  a  trace  will  be  obtained.  It  is  only  the  bitter  almond 
which  contains  amygdaline  ;  the  sweet  variety  is,  therefore,  incapable  of  yielding  the  essence 
by  fermentation.  But  sweet  almonds  resemble  the  bitter  in  containing  emulsine  ;  and  it  is 
exceedingly  interesting — as  illustrating  the  truth  of  the  explanation  given  above — that  if  a 
little  amygdaline  be  added  to  an  emulsion  of  sweet  almonds,  the  bitter  almond  essence  is 
immediately  formed.  The  largest  proportion  of  essential  oil  is  obtained  when  the  marc  is 
digested,  previous  to  distillation,  with  twenty  times  its  weight  of  water,  for  a  day  and  a 
night.     A  temperature  of  100"  is  the  most  favorable  for  the  digestion. — C.  G.  W. 

ANCHOR.  The  metal  employed  for  anchors  of  wrought-iron  is  known  as  "  scrap 
iron,"  and  for  the  best  anchors,  such  as  Lenox's,  they  also  use  good  "  Welsh  mine  iron." 

It  is  not  practicable,  without  occupying  more  space  than  can  be  afforded,  to  describe  in 
detail  the  manufacture  f  an  anchor.  It  does  not,  indeed,  appear  desirable  that  we  should 
do  so,  since  it  is  so  special  a  form  of  mechanical  industry,  that  few  will  consult  this  volume 
for  the  sake  of  learning  to  make  anchors.  The  following  will  therefore  suffice  :  The  an- 
chor smith's  forge  consists  of  a  hearth  of  brickwork,  raised  about  9  inches  above  the  ground, 
and  generally  about  7  feet  square.  In  the  centre  of  this  is  a  cavity  for  containing  tlic  fire. 
A  vertical  brick  wall  is  built  on  one  side  of  the  hearth,  which  supports  the  dome,  and  a  low 
chimney  to  carry  off  the  smoke.  Behind  this  wall  are  placed  the  bellows,  with  which  the 
fire  is  urged  ;  the  bellows  being  so  placed  that  they  blow  to  the  centre  of  the  fire.  The  an- 
vil and  the  crane  Ijy  which  the  heavy  masses  of  metal  are  moved  from  and  to  the  fire  are 
adjusted  near  the  hearth.  The  Hercules,  a  kind  of  stamping  machine,  or  the  steam  ham- 
mer, need  not  be  described  in  this  place. 

To  make  the  anchor,  bars  of  good  iron  are  brought  together  to  be  fagoted  ;  the  num- 
ber varying  with  the  size  of  the  anchor.  The  fagot  is  kept  together  by  hoops  of  iron,  and 
the  whole  is  placed  upon  the  properly  arranged  hearth,  and  covered  up  l)y  small  coals, 
which  are  thrown  upon  a  kind  of  oven  ma<le  of  cinders.  Great  care  and  good  management 
are  required  to  keep  this  temporary  oven  sound  during  the  combustion  ; — a  smith  strictly 


94: 


ANCHOK. 


attends  to  this.  When  all  is  arranged,  the  bellows  are  set  to  work,  and  a  blast  urged  on  the 
fire  ;  this  is  continued  for  about  an  hour,  when  a  good  welding  heat  is  obtained.  The  mass 
is  now  brought  from  the  fire  to  the  anvil,  and  the  iron  welded  by  the  hammers.  One  por- 
tion having  been  welded,  the  iron  is  returned  to  fire,  and  the  operation  is  repeated  until  th« 
whole  is  welded  into  one  mass. 


This  will  be  understood  by  referring  to  the  annexed  figures,  {fr/.  30,)  in  which  the  bars 
for  the  shanks,  a  a,  and  the  arms,  n  b,  are  shown,  in  plan  and  sections,  as  bound  together, 
and  their  shapes  after  being  welded  before  union  ;  and  c  c  represents  the  palm. 

The  diflt'erent  parts  of  the  anchor  being  made,  the  arms  are  united  to  the  end  of  the 
shank.  This  must  be  done  with  great  care,  as  the  goodness  of  the  anchor  depends  entirely 
upon  this  process  being  effectively  performed.  The  arms  being  welded  on,  the  ring  has  to 
be  formed  and  welded.  The  ring  consists  of  several  bars  welded  together,  drawn  out  into 
a  round  rod,  passed  through  a  hole  in  the  shank,  bent  into  a  circle,  and  the  ends  welded 
together.  When  all  the  parts  are  adjusted,  the  whole  anchor  is  brought  to  a  red  heat,  and 
hammered  with  lighter  hammers  than  those  used  for  welding,  the  object  being  to  give  a 
finish  and  evenness  to  the  surface. 

The  toughest  iron  which  can  be  procured  should  be  used  in  the  manufacture  of  an  anchor, 
upon  the  strength  of  which  both  the  security  of  valuable  lives  and  much  property  depend. 

The  following  drawings  {Ji().  31)  show  an  anchor  on  the  old  plan,  and  the  ■dissected  parts 
of  which  it  is  composed  : — 


ANCHOR. 


95 


and  the  annexed,  {fig.  32,)  the  patent  anchor  as  invented  by  Mr.  Perring,  with  its  several 
parts  dissected  as  before  : — 


Previously  to  tlie  introduction  of  Lieutenant  Rodger's  gniall-palmed  anchor,  ships  were 
supplied  with  heavy,  cumbersome  contrivances  with  long  shanks,  and  broad  palms  extending 
half  way  up  the  flukes.  So  Vjadly  were  they  proportioned,  that  it  was  no  uncommon  thing 
for  them  to  break  in  falling  on  the  bottom,  particularly  if  the  gi-ound  was  rocky.  But,  if 
once  firmly  imbedded  in  stiff  holding  ground,  there  was  considerable  difficulty  in  breaking 
them  out.  The  introduction  of  the  small  palm,  therefore,  forms  an  important  era  in  the 
history  of  anchors. 

The  next  important  'introduction  was  Porter's  anchor,  with  movable  flukes  or  arms. 
One  grand  ol)ject  souglit  to  be  attained  here,  was  the  prevention  of  fouling  by  the  cable.  It 
was  considered,  also,  that  as  great  injury  was  frequently  occasioned  by  a  ship  grounding  on 
her  anchor,  the  closed  upper  arm  would  remedy  the  evil.  It  was  found,  however,  that  the 
anchor  would  not  take  the  ground  properly  as  at  first  constructed,  and  hence  the  "  shark's 
fins  "  upon  the  outside  of  each  fluke. 

Rodger's  invention  was  for  some  time  viewed  with  distrust ;  but,  from  time  to  time,  im- 
provements were  introduced,  until  the  patent,  which  gained  the  Exhibition  prize,  was 
brought  out.     On  this  the  jurors  reported  as  follows  : — 

"  Many  remarkable  improvements  have  been  recently  made  by  Lieutenant  Rodger, 
R.X.,  insuring  a  better  distribution  of  the  metal  in  the  direction  of  the  greatest  strains. 
The  palm  of  the  anchor,  instead  of  being  flat,  presents  two  inclined  planes,  calculated  for 
cutting  the  sand  or  mud  instead  of  resisting  per-pendicularly ;  and  the  consequence  is,  that 
these  new  anchors  hold  much  better  in  the  ground.  The  committee  of  Lloyd's — so  compe- 
tent to  judge  of  every  contrivance  likely  to  preserve  ships — have  resolved  to  allow  for  the 
anchors  of  the  ships  they  insure  a  sixth  less  weight  if  made  according  to  the  plan  of  Lieu- 
tenant Rodger." 

The  orighial  Porter's  anchor  has  also  undergone  considerable  modification  ;  and,  under 
the  name  of  "  Trotman's  anchor,"  has  now  a  conspicuous  place. 

Another  invention  is  that  of  Mitcheson's,  which,  in  form  and  proportions,  strongly  re- 
sembles Rodger's  ;  but  the  palm  is  that  adopted  in  Trotman's,  or  Porter's  anchor.  It  is  a 
trifle  longer  in  the  shank  than  Rodger's,  and  has  a  peculiar  stock,  which — although  original 
in  its  form — lacks  originality  in  its  design,  since  Rodger  had  previously  introduced  a  plan 
for  an  iron  stock  to  obviate  the  weakness  caused  by  making  a  hole  for  the  stock  to  pass 
through.  Mr.  Lenox  was  the  inventor  of  an  anchor  which  differed  somewhat  from  the 
Admiralty's  anchor — a  modification  of  Rodger's, — in  being  shorter  in  the  shank  and  thicker 
in  the  flukes,  the  palms  lieing  spade-shaped.  Mr.  J.  Aylen,  the  Master-Attendant  of  Slioer- 
ness  Dockyard,  modified  the  Admiralty's  anchor.  Instead  of  the  inner  part  of  the  fluke, 
from  the  crown  to  the  pea,  being  rounded,  as  in  the  Admiralty  plan,  or  squared,  as  in 
Rodger's  and  Mitcheson's,  it  is  hollowed.  An  American  anchor  known  as  Isaac's,  has  a  flat 
bar  of  iron  from  palm  to  palm,  passing  the  shank  clliptically  on  both  sides  ;  and  from  the 
end  of  the  stock  to  the  centre  of  the  shank  two  other  l)ars  are  fixed  to  prevent  its  fouling. 

With  the  anchors  tlms  briefly  descrit)ed  the  Admiralty  ordered  trials  to  bo  made  at  Wool- 
wich, and  at  the  Non;.  The  results  of  those  trials — the  particulars  of  which  need  not  be  given 
here — were,  that  Mitcheson's,  Trotman's,  Lenox's,  and  Rodger's,  were  selected  as  the  l)est. 


96 


ANCHOE. 


A  competent  authority,  writing  in  the  United  Service  Gazette,  says : — "  The  general 
opinion  deduced  from  the  scries  of  experiments  is,  that  although  Miteheson's  has  been  so 
successful,  the  stock  is  not  at  present  seaworthy.  Trotman's  has  come  out  of  the  trial  very 
successfully,  hut  the  construction  is  too  coniplicatei.1  to  render  it  a  good  working  anchor. 
When  once  in  the  ground,  its  holding  i)ropertics  are  very  superior  ;  in  fact,  a  glance  at  its 
grasp  will  show  that  it  has  the  capabilities  of  an  anchor  of  another  construction  one-fifth 
larger.  There  arc,  however,  drawbacks  not  easily  to  be  overcome.  Its  taking  the  ground 
is  more  precarious  than  with  other  anchors  ;  and  if  a  ship  sliould  part  her  cable,  it  would 
scarcely  be  possible  to  sweep  the  anchor.  It  is  also  an  awkward  anchor  to  fish  and  to  stow. 
Yet  there  are  other  merits  which  render  it,  upon  the  whole,  a  most  valuable  invention,  and 
no  ship  should  go  to  sea  without  one.  Of  Lenox's,  it  is  sufficicvt  to  say  that  it  has  been 
found  equal  to,  aiid  that  it  lias  gained  an  advantage  over,  Kodger's;  but  so  strong  is  the 
professional  feeling  in  favor  of  the  latter,  that  it  will  ever  remain  a  favorite.  Our  recom- 
mendation would  be  thus  : — Lenox  and  Kodger  for  bower  anchors,  Mitcheson  for  a  sheet, 
and  Trotman  for  a  spare  anchor." 

The  following  table  gives  at  one  view  the  results  of  the  experiments  made  by  the  Ad- 
miralty upon  breaking  the  trial  anchors,  and  the  time  occupied  upon  each  experiment : — 


Anchors. 

W 

eight 

Proof- 
strain. 

First 
Craclc. 

Broke. 

Time  in 
Breaking. 

Cwts. 

qrs. 

lbs. 

Tons. 

Tons. 

Tons. 

Minutes.  1 

Lieut.  Rodger's 

19 

0 

8 

H)i 

45 

'73i 

21        1 

Brown  and  Lenox's   - 

20 

3 

U 

2H 

.    4-li 

47 

7       1 

Isaac's       .... 

21 

0 

U 

21| 

58 

63 

10 

Trotman's           ... 

21 

1 

10 

211 

51 

53i 

18 

Honiball's 

20 

3 

7 

21i 

54 

nn 

42 

Admiralty's 

20 

2 

G 

21i 

40 

56^ 

20 

Ayleii's      .... 

21 

1 

0 

21f 

44 

47i 

6 

(^ 


v/ 


33 


The  history  of  the  introduction  of  Lenox's  anchors  to  the  British  navy  was  as  follows  : — 
After  sundry  attempts  to  induce  the  Admiralty  to  give  up  entirely  the  use  of  hempen 
cal)lo  anchors,  in  consequence  of  their  breaking  when  applied  to  chain  cables,  Mr.  Lenox,  in 
1832,  was  permitted  to  alter  some  of  the  old  anchors  to  such  proportions  and  shape  as 
would  enable  them  to  stand  a  proof-strain  upon  the  machine  in  Woolwich  Dockyard.  It 
was  found,  as  previously  apprehended  and  asserted,  that,  from  the  ineciuality  of  material  in 
the  old  anchors,  not  above  one  in  three  was  successfully  altered,  and  Mr.  Lenox  was  ordered 
to  supply  new  anchors,  which  were  proved,  and  then  approved  of.  This  state  of  things 
continued  until  1838,  when  Mr.  Lenox  was  requested  to  reconsider  and  complete  the  shape 
and  proportions  of  anchors  for  the  navy,  with  a  view  to  a  contract  being  given  out  for 
the  supply  of  such  anchors  to  the  service.     Then  was  constructed    the  shape  called  the 

"  Admiralty,"  or  "  Sir  William  Parker's  Anchor,"  (Sir 
William  being  then  Store  Lord.)  Mr.  Lenox  suggested 
to  Sir  William  the  doing  away  with  every  sharp  edge 
and  line  in  an  anchor,  and  adopting  the  smooth  long- 
oval  (in  the  section)  for  the  general  shape  of  shank 
and  arm.  This  was  approved  of  by  Sh-  William,  and  he 
brought  it  out  as  his  anchor.  An  entire  table  of  pro- 
portions was  furnished ;  but  that  it  might  meet  with  no 
opposition  from  the  influence  of  dockyard  authority,  it 
was  sent  to  the  officers  of  Portsmouth  Yard  for  their 
approval.  They  returned  it,  after  a  few  months,  with 
some  slight  alterations  in  the  proportions  of  some  of 
the  sizes,  and  recommended  the  construction  to  be  on 
"  Perring's  principle  "  of  the  cushioned,  or  made-up 
crown.  It  was  so  adopted,  and  continued  to  be  made 
by  Brown  and  Lenox  for  about  a  year  or  two,  when 
the  great  and  unnecessary  expense  incurred  by  the  plan 
was  pointed  out.  It  was  contended  it  was  without  any 
good  ;  because,  if  the  crown  of  the  anchor,  or  any  shut 
or  weld,  was  made  sound  and  perfect,  the  amalgamation 
of  the  grain  of  the  iron  would  be  complete,  and  assume 
its  full  power  or  strength,  whatever  way  it  might  be  put 
together ;  and  the  strongest  form  was  that  which  exposed 
the  least  surface  of  iron  to  the  welding  heat,  and  consequently  to  injury.  About  the  latter  end 
of  1839,  the  subject  was  again  openccl.  Mr.  Lenox  renewed  his  objections,  by  letter,  to  Sir 
William  Parker,  to  "  Perring's  plan  "  of  shutting-up,  and  the  consequence  was — a  contract 
with  specification,  &c.  &c.,  appeared,  and  an  improved  or  modified  plan  of  shutting-up  (as  it 


ANCHOR. 


97 


is  called)  was  proposed  by  Mr.  Tyler,  master-smith  of  Portsmouth  Yard,  which  was  adopted  ; 
and  Mr.  Lenox's  shape  and  proportions,  (slightly  altered,  as  before  said,)  came  out  as  "  Sir 
William  Parker's,"  or  the  "  Admiralty  Anchor,"  and  continued,  until  after  the  trials  in 
1852,  with  every  success  hi  actual  service  that  a  good  anchor  could  maintain^  and  they  were 
made  and  sold  in  quantities  to  all  the  world. 


In  the  navy  of  England,  and  in  nearly  all  foreign  navies,  this  anchor,  of  which  fig.  33 
represents  the  form,  was  adopted.  They  are  also  largely  employed  in  the  merchant  service  ; 
but  these  are  not  so  nicely  proportioned  as  the  anchors  made  for  the  Government,  nor  are 
they  so  highly  finished.  Many  merchant  captains,  however,  take  Rodger's  anchor,  and  our 
steamers  almost  invariably  take  Porter's  or  Trotman's  anchor. 


Vol.  hi.— 7 


98 


ANCHOK. 


Trotmaii's  Anchor  is  represented  in  fg.  34,  under  its  various  positions.  Although  for 
convenience  Trotman's  anchor  is,  as  we  have  already  stated,  largely  used  by  the  merchant 
steamers,  we  cannot  but  feel  that  the  separation  of  the  fluke  from  the  shaft,  although  it  may 
be  in  many  cases  unobjectionable,  is  attended  with  the  risk  that  when,  in  an  emergency,  the 
anchor  is  required,  the  means  of  connection  may  be  at  fault. 

Captain  Hall's  anchor  is  a  very  valuable  one,  from  the  circumstance  that  it  is  capable  of 
division,  as  shown  in  fir/.  35,  so  that  it  can  be  taken  out  in  boats. 

There  are  various  other  shapes  of  anchors ;  but  attention  has  been  confined  to  those 
generally  employed. 

We  are  not  in  a  position  to  offer  any  opinion  upon  the  value  of  the  several  anchors 
which  have  been  named.  Having  described  their  peculiarities,  there  remains  but  little  to 
be  said.  The  solidity  of  Lenox's  anchors — as  shown  in  Jig.  36,  and  again  in  their  more 
recent  modifications,  in  plan  and  section,  with  the  new  form  of  iron  stock,  ^g.  37 — has 
recommended  them  strongly,  and  hence  their  general  use. 


The  weight  of  anchors  for  diff'erent  vessels  is  proportioned  to  the  tonnage.  The  follow- 
ing table  shows  the  number  of  anchors  now  carried,  and  the  weights  of  each  anchor,  by 
merchant  vessels  by  the  regulation  of  Lloyd's. 

Lloyd's  Regulation  for  the  Number  and  Weights  of  Anchors  for  Merchant  Vessels. 


Ship*fl  Tonnage. 

Bower. 

Stream. 

Kedge. 

Bower, 
Wood  Stock. 

Bower, 
Iron  Stock, 

Stream. 

Kedge. 

Second 
Kedge. 

Ton». 

Cwt. 

Cwt. 

Cwt, 

Cwt. 

Cwt. 

50 

2 

3 

4 

U 

75 

2 

4 

5 

U 

100 

2 

5 

7 

2i 

H 

150 

2 

8 

10 

8i 

H 

200 

3 

10 

12 

4^ 

2J 

250 

8 

2 

13 

15 

5 

2i 

800 

8 

2 

15 

IT 

6 

8 

350 

8 

2 

IT 

20 

6i 

8i 

400 

3 

2 

19 

22 

Ik 

8* 

500 

8 

2 

2-3 

26 

9 

4* 

600 

8 

2 

26 

80 

10 

5 

2i 

TOO 

8 

1 

2 

29 

34 

11 

5i 

2J 

800 

3 

1 

2 

81 

86 

13 

6 

3 

900 

8 

2 

83 

89 

12 

6i 

8} 

1,000 

8 

J 

2 

85 

41 

12 

6t 

3} 

i,ino 

3 

2 

87 

44 

12 

7 

31. 

1,200 

8 

1 

2 

89 

46 

12 

7* 

8i 

1,400 

8 

1 

2 

41 

48 

12 

7J 

4 

1,600 

8 

1              2 

43 

50 

14 

6i 

4 

1,800 

3 

1              2 

45 

52 

14 

8i 

4.1 

2,000 

4 

1              2 

4T 

54 

14 

9 

4* 

ANGOEA  WOOL. 


99 


ANCHOVY.  {Anchoii^,  Fr. ;  Acciughe,  It.  ;  Anschove,  Germ.)  The  Clupea  encrasi- 
colus  of  Linnajus,  a  small  fish,  resembling  the  sprat,  common  in  the  Mediterranean  Sea. 
The  Gorgona  anchovy  is  considered  the  best.  Sardines  (which  see)  are  sometimes  substi- 
tuted for  anchovies. 

ANDIRONS,  or  HAND-IRONS,  also  called  Firedogs.  Before  the  introduction  of  raised 
and  close  fireplaces  these  articles  were  in  general  use.  Strutt,  in  1775,  says  :  "  These  awnd- 
irons  are  used  at  this  day,  and  are  called  '  cob-iro7is ' ;  they  stand  on  the  hearth,  where  they 
burn  wood  to  lay  it  upon  ;  their  fronts  are  usually  carved,  with  a  round  knob  at  the  top  ; 
some  of  them  are  kept  polished  and  bright :  anciently  many  of  them  were  embellished  with 
a  variety  of  ornaments." 

ANEMOMETER.  {&v€fios,  wind  ;  ^erpew,  to  measure.)  An  instrument  or  machine  to 
measure  the  wind,  its  direction  and  force.  Three  descriptions  of  anemometers  are  now 
usually  employed  : — 1,  Dr.  Whewell's  ;  2,  Mr.  FoUett  Osier's  ;  3,  Dr.  Robinson's.  This  is 
not  the  place  to  describe  either  of  those  most  ingenious  instruments,  a  full  account  of  which 
will  be  found  in  the  "  Transactions  of  the  British  Association,"  and  of  the  "  Royal  Irish 
Academy." 

ANEROID  BAROMETER.  This  instrument  was  invented  by  M.  Vidi,  of  Paris.  In  its 
latest  form  it  consists  of  a  cylindrical  case,  about  4  or  6  inches  in  diameter,  and  2J  inches 
deep,  in  which  lies  a  thin  metal  box,  near  to,  and  parallel  with,  the  curved  boundary  of  the 
case,  its  two  ends  being  distant  about  half  an 
inch  from  each  other.  From  this  box  the  air 
has  been  partially  exhausted,  and  the  pressure 
of  the  external  atmosphere  on  it  causes  it  to 
alter  its  form.  The  accompanying  figure  (38) 
shows  a  section  of  this  box.  It  is  made  of 
thin  corrugated  plates  of  metal,  so  that  its  elas- 
ticity is  great.  By  means  of  the  tube  f,  the 
air  is  partially  exhausted,  when  the  box  takes 
the  form  shown  by  the  dotted  lines.  A  small 
quantity  of  gas  is  introduced  after  exhaustion,  the  object  of  which  is  to  compensate  for  the 
varying  elasticity  of  the  metal  at  different  temperatures.  The  pressure  of  the  air  on  the  box 
in  ordinary  instruments  is  between  40  and  50  lbs.,  and  it  will  be  easily  understood  that  any 
variation  in  this  pressure  will  occasion  the  distances  between  the  two  plates  to  vary,  and 
consequently  the  stalk  will  have  a  free  motion  in  or  out.  This  is,  by  an  ingenious  contriv- 
ance, changed  from  a  vertical  motion  to  a  motion  parallel  to  the  face  of  the  dial,  and  this 
is  converted  into  a  rotatory  one  by  the  application  of  a  watch-chain  to  a  small  cylinder  or 
drum.  The  original  very  slight  motion  is  augmented  by  the  aid  of  levers.  This  is  so  effec- 
tually done,  that  when  the  corrugated  surfaces  move  through  only  the  250th  part  of  an 
inch,  the  index  hand  on  the  face  turns  over  a  space  of  three  inches.  The  extreme  portabil- 
ity of  this  little  instrument,  and  its  comparative  freedom  from  risk  of  injury,  render  it  ex- 
ceedingly useful  to  the  traveller.  Its  accuracy  is  proved  by  the  experiments  of  Professor 
Lloyd,  who  placed  one  under  the  receiver  of  an  air-pump,  and  found  that  its  indications 
corresponded  with  those  of  the  mercurial  gauge  to  less  than  O'Ol  of  an  inch  ;  and  within 
ordinary  variations  of  atmospheric  pressure  the  coincidences  are  very  remarkable. — Lloyd, 
JVichol,  Drew. 

ANGELICA.  {Angilique,  Fr.  ;  Angclika,  Germ.)  The  archnngclica  officinalis.  The 
dried  angelica  root  is  imported  from  Hamburg  in  ca.sks.  The  tender  stems,  stalks,  and  the 
midribs  of  the  leaves  are  made,  with  sugar,  into  a  sweetmeat,  (candied  angelica.)  The  an- 
gelica root  and  seeds  are  used  by  rectifiers  and  compounders  in  the  preparation  of  gin,  and 
as  an  aromatic  flavoring  for  "  bitter.s."  It  is  cultivated  in  some  moist  places  in  this  country. 
In  1856  we  imported  231  tons  of  angelica  root. 

ANGORA  WOOL.  {Poil  da  chevron  d'' Angora.,  Fr.)  Called  also  angola  and  angona. 
The  wool  of  the  Angora  goat,  {Capra  Angorensis^)  employed  in  the  manufacture  of  the 
shawls  of  Cashmere,  &c.  This  is  obtained  from  the  long-haired  goat  of  Angora,  to  which 
province  this  animal  is  peculiar.  Lieutenant  Conolly  has  given  an  account  of  this  goat  and 
some  other  varieties  : — 

"  The  country  where  it  is  found  was  thus  described  to  us — '  Take  Angora  as  a  centre, 
then  Kizzil  Ermak  (or  Haly's)  Chomgerc,  and  from  8  to  10  hours'  march  (say  30  miles) 
beyond ;  Beybazar,  and  the  same  distance  beyond,  to  near  Nalahan  ;  Sovree,  Ilissar, 
Yoorrook,  Tosiah,  Costambool,  Geredch,  and  Cherkesh,  from  the  whole  of  which  tract  the 
common  bristly  goat  is  excluded,  and  the  white-haired  goat  alone  is  found.'  The  fleece  of 
the  white  Angora  goat  is  called  liftik,  (the  Turkish  for  goats'  hair,)  in  distinction  to  yiin,  or 
yapak\  sheep's  wool.  After  the  goats  have  completed  their  first  your,  they  are  clipped 
iinnuallj,  in  April  or  May,  and  yield  progressively,  until  they  attain  full  growth,  from  150 
drachms  to  Ih  oke  of  tiftik,  (from  1  11).  to  4  lbs.  English.)  "  The  hair  of  the  tiftik  goat  is 
exported  from  its  native  districts  raw,  in  yarn,  and  woven  in  the  delicnte  stuffs  for  which  An- 
gora has  been  long  celebrated.     The  hist  are  chiefly  consumed  in  Turkey,  while  the  yarn 


100 


ANILINE. 


and  raw  material  are  sent  to  Fiance  and  England.  It  appeai-s  that  the  first  parcels  of  An- 
gora wool  were  shipped  from  Constantinople  for  England  in  1820,  and  was  so  little  appre- 
ciated that  it  fetched  only  10c/.  the  pound.  The  exports  from  Constantinople  then  increased 
as  follows  : — 

1836 3,841  bales 

1837 2,261      " 

1838 5,528      " 

'•  Within  the  last  two  or  three  years,  a  new  texture  made  of  goats'  wool  has,  however, 
been  introduced  both  into  France  and  this  country,  which  calls  for  particular  attention. 
This  texture  consists  of  stripes  and  checks  expressly  manufactured  for  ladies'  dresses,  and 
having  a  soft  feel  and  silky  appearance.  The  wool  of  which  this  article  is  made  is  chiefly 
the  wool  of  the  Angora  goat.  This  wool  reaches  us  through  the  Mediterranean,  and  is 
chiefly  shipped  at  Smyrna  and  Constantinople.  In  color  it  is  the  whitest  known  in  the 
trade,  and  now  more  generally  used  in  the  manufacture  of  fine  goods  than  any  other. 
There  are,  however,  other  parts  of  Asiatic  Turkey  from  which  limited  supplies  are  received ; 
but  in  tjuality  not  so  good  as  that  produced  in  Angora.  After  the  manufacture  of  shawls 
with  goats'  wool  declined  in  France,  this  raw  material  remained  neglected  for  a  long  while. 
About  two  or  three  years  ago  (1852)  however,  the  French  made  another  attempt,  and 
brought  out  a  texture  for  ladies'  dresses  in  checks  and  stripes,  which  they  call  '  poll  de 
c/ievre.^  The  warp  is  a  fine  spun  silk,  colored,  and  the  weft  Angora  or  Syrian  white  wool, 
wliich  was  thus  thrown  on  the  surface.  This  article  has  a  soft  feel,  and  looks  pretty,  but  in 
wearing  is  apt  to  cut.  The  price  of  a  dress  of  French  manufacture  has  been  from  21.  10s. 
to  3/.  ;  but  by  adopting  a  cotton  warp,  the  same  article  is  now  made  in  England  and  sold 
for  15.S. ;  and  it  is  found  that  the  cotton  warp,  as  a  mixture,  suits  the  goats'  hair  best." — 
Soutfie;/  on  Colonial  S/icep  and  11  oo/,  London,  1852. 

Angora  goats'  wool  is  used  for  the  manufacture  of  plush,  and  for  coach  and  decorative 
laces.  It  is  also  used  extensively  for  buttons,  button-holes,  and  the  braidings  of  gentle- 
men's coats.  It  is  equally  made  up  into  a  light  and  fashionable  cloth,  suited  for  paletots 
and  overcoats,  possessing  the  advantage  of  repelling  wet.  In  France  this  article  is  now 
applied  to  the  manufacture  of  a  new  kind  of  lace  which  in  a  great  measure  supersedes  the 
costly  fabrics  of  Valenciennes  and  Chantilly.  The  Angora  wool  lace  is  more  brilliant  than 
that  made  from  silk,  and  costing  only  half  the  price,  it  has  come  into  very  general  wear 
among  the  middle  classes.  The  same  material  is  also  manufactured  into  shawls,  which  sell 
from  4/.  to  10/.  each.  There  is  much  difficulty  in  ascertaining  the  quantity  of  Angora 
wool  used  in  Franco,  as  in  the  returns  it  is  mixed  up  with  the  wool  of  goats  of  Thibet,  all 
being  entered  as  poil  de  Cachemire.     See  Mohaiu. 

ANILINE.  (C"  H^  N.  Syn.  Plievylamine,  Cyanol,  Benzidam,  Crystalline.)  This 
organic  base  having  recently  met  with  an  important  application  in  the  arts  in  the  production 
of  a  beautiful  dye-color,  by  Mr.  William  H.  Perkin,  a  short  description  of  the  methods  of 
preparing  it,  and  of  some  of  its  characters,  becomes  necessary ;  though  for  details  of  its 
most  interesting  relations  in  scientific  chemistry,  we  must  refer  to  the  "  Dictionary  of 
Cliemistry." 

Preparation. — There  are  few  bodies  which  admit  of  being  prepared  in  a  greater  variety 
of  ways — all  of  them  interesting  in  tracing  the  chemical  history  of  this  most  curious  body  ; 
but  we  will  only  here  describe  that  one  which  might  be  most  advantageously  carried  out  on 
a  manufacturing  scale.  Probably  the  most  abundant  source  of  aniline  is  the  basic  oil  of 
coal  tar. 

The  oil  is  agitated  with  hydrochloric  acid,  which  seizes  upon  the  basic  oils ;  after  decant- 
ing the  clear  liquor,  which  contains  the  hydrochlorates  of  these  oils,  it  is  evaporated  over  an 
open  fire  until  it  begins  to  disengage  acrid  fumes,  which  indicate  a  commencement  of  de- 
composition, and  then  filtered  to  separate  any  adhering  neutral  compounds.  The  clear 
liquor  is  then  decomposed  with  potash  or  milk  of  lime,  which  liberates  the  bases  themselves 
in  the  form  of  a  brown  oil,  consisting  chiefly  of  a  mixture  of  aniline  (C"  IP  N)  and  leucol 
or  quinoleinc,  (C"  H"  N.)  This  mixture  is  submitted  to  di.stillation,  and  the  aniline  is  chiefly 
found  in  that  portion  which  passes  over  at  or  about  360°  F.,  (182"  C.  :)  repeated  rectification 
and  collection  of  the  product  distilling  at  this  temperature  purify  the  aniline;  but  to 
cnnipleto  the  purification,  it  is  well  to  treat  the  partially  purified  aniline  once  more  with 
hydrochloric  acid,  to  separate  the  bases  again  by  an  alkali,  and  then  to  rectify  carefully. 

The  violet  reaction  of  aniline  with  solution  of  bleaching  powder  enables  tiie  operator  to 
test  the  di.stillate  from  time  to  tim.e,  to  ascertain  when  aniline  ceases  to  pass  over,  since 
leucol  does  not  possess  this  property. — Ilofmnnn. 

Aniline  may  also  be  obtained  in  quantity  from  indigo. 

When  indigo-blue  (see  Inpioo)  is  dissolved  by  the  aid  of  heat  in  a  strong  solution  of 
potash,  and  the  mass,  after  evaporation  to  dryness,  submitted  to  destructive  distillation,  it 
intumesccs  considerai)!y,  and  aniline  is  liberated,  which  condenses  in  the  receiver  in  the 
form  of  a  brown  oil,  together  with  a  little  water  and  ammonia  disengaged  with  it.     The 


ANILINE.  101 

aniline  is  purified  by  rectification,  as  in  the  method  before  described.     By  this  process  the 
quantity  ot'anihne  obtained  is  about  18  to  20  per  cent,  of  the  indigo  used. — Fritzche. 

By  treatment  with  potash,  the  indigo-blue  (C®  H^  NO")  is  converted  into  chrysanilio 
acid  and  anthranilic  acid,  (C*  IV  NO^ ;)  and  it  is  this  latter  body  which,  by  destructive  dis- 
tillation, yields  carbonic  acid  and  aniline. 

G"  IP  NO^  =  C'=  n'  N  +  2C01 
Nitrobenzole  [ivhich  see)  may  be  converted  into  aniline,  either  by  the  action  of  sulphu- 
retted hydrogen — 

C'^  IP  NO'  -f  GUS  =  C'"-  H'  N  -f  4nO  +  CS ; 

Nitrobenzole.  Aniline. 

or,  more  conveniently,  as  has  been  recently  shown  by  M.  Bechamp,  by  the  action  of  a  basic 
acetate  of  iron. 

For  this  purpose  the  following  proportions  have  been  found  convenient  by  the  writer : 
mix  in  a  retort  i  lb.  of  iron  filings,  with  about  2  ounces  of  acetic  acid,  then  add  about  an 
equal  volume  of  nitrobenzole.  After  a  few  minutes  a  brisk  effervescence  sets  in,  and  the 
aniline  distils  over  together  with  water.  The  reaction  may  require  to  be  aided  by  the 
application  of  a  very  gentle  heat ;  but  it  takes  place  with  the  greatest  ease,  and  a  very  tol- 
erably sufficient  condensing  arrangement  should  be  employed.  The  aniline  having  so  nearly 
the  density  of  water,  does  not  readily  separate  on  the  surface,  but  the  addition  of  a  few 
drops  of  ether,  which  dissolves  in  the  aniline,  brings  it  to  the  surface.  It  may  then  be 
decanted  off,  dried  by  standing  for  a  short  time  over  chloride  of  calcium,  and  then  purified 
by  rectification,  as  before  described. 

Properties. — Aniline  is  one  of  the  organic  basic  derivatives  of  ammonia.  In  fact,  it  may 
be  viewed  as  ammonia  in  which  one  equivalent  of  hydrogen  is  replaced  by  the  compound 
radical  Phenyl  {G"  H')  thus  :— 

(   C"  H=* 

N    \   H 
(   H 
Just  as  phenyl  is  one  of  a  series  of  homologous  radicals,  so  aniline  is  the  first  of  a  series 
of  homologous  bases,  in  which  the  one  equivalent  of  hydrogen  is  replaced  by  these  radicals, 
respectively,  thus  : 

Homologous  Cases. 


Ilomologous 

Radicals. 

I 

Phenyl     - 

-     C'=  H'      - 

-      Aniline 

Toluyl      - 

-     C"H'      - 

-      Toluidine 

Xylyl       -        - 

-     C"  H'      - 

Xylidine 

Cumyl     - 

-    C"  H"     - 

—     Cumidine 

Cymyl     - 

-     C"  EP^     - 

—     Cymidine 

N 


N 


N 


IP 

Q20  JJ13 


When  pure,  it  is  a  colorless  liquid  of  a  high  refractive  power ;  density  P028,  and  of  an 
aromatic  odor.  It  is  slightly  soluble  in  water,  and  mixes  in  all  proportions  with  alcohol 
and  ether.  It  boils  at  360^  F.,  (182°  C.)  It  dissolves  sulphur  and  phosphorus  when  cold, 
and  coagulates  albumen.  It  has  no  action  on  litmus-paper,  but  turns  delicate  vegetable 
colors,  such  as  dahlia-petal  infusion,  blue. 

Its  basic  characters  are  well  developed  thus : — it  precipitates  the  oxides  from  the  salts 
of  iron,  zinc,  and  alumina,  just  like  ammonia,  and  yields,  with  bichloride  of  platinum,  a 
double  salt  similar  to  ammonia,  the  platino-chloride  of  aniline,  (C^  H'  N,  IICl,  PtCP,)  which 
on  ignition  is  entirely  decomposed,  leaving  only  a  residue  of  platinum.  These  characters, 
together  with  the  beautiful  blue  color  which  it  strikes  with  solution  of  bleaching  powder,  or 
the  alkaline  hypochlorites  generally,  are  sufficient  for  the  recognition  and  distinction  of  this 
body. 

Salts  of  Anilink. — Aniline  combines  with  acids  forming  a  long  series  of  salts  which 
are  in  every  respect  analogous  to  the  corresponding  salts  of  ammonia.  They  are  nearly  all 
soluble  and  crystallizable,  and  are  decomposed  by  the  mineral  alkalies  with  liberation  of  ani- 
line.    They  are  generally  colorless,  but  become  red  by  exposure  to  the  air. 

Sulphate  of  Aniline.  (C"  W  N  ;  HO,  SO'.) — This  salt  is  employed  in  the  manufacture 
of  Mr.  Perkin's  aniline  colors.  It  is  prepared  by  treating  aniline  with  dilute  sulphuric  acid, 
and  evaporating  gently  till  the  salt  separates.  It  crystallizes  from  boiling  alcohol  in  the 
form  of  beautiful  colorless  plates  of  a  silvery  lustre,  for  the  salt  is  scarcely  at  all  soluble  in 
cold  alcohol.     It  is  very  soluble  in  water,  but  insoluble  in  ether. 

The  crystals  redden  by  exposure  to  the  air ;  they  can  be  heated  to  the  boiling  point  of 


102  ANISEED. 

water  without  change,  but  when  ignited  they  are  charred  with  disengagement  of  aniline  and 
sulphiirous  acid. 

Oxalate  of  Aniline.  (C^  H'  N  ;  HO,  C  01)— This  is  one  of  the  best-defined  salts  of 
aniline :  it  separates  as  a  crystalline  mass  on  treating  an  alcoholic  solution  of  oxalic  acid 
with  aniline.  It  is  very  soluble  in  hot  water,  much  less  so  in  cold,  only  slightly  soluble  in 
alcohol,  and  insoluble  in  ether. 

A  large  number  of  other  salts  are  known.  The  hydrochlorate,  hydrobromate,  bydrio- 
date,  nitrate,  several  phosphates,  citrate,  tartrate,  &c.  &c.  ;  but  tliey  are  of  purely  scientific 
interest.  The  same  remark  applies  to  the  various  products  of  the  decomposition  of  aniline, 
which  have  been  so  ably  investigated  by  Fritzche,  Zinin,  Hofmann,  Gerhardt,  and  other 
chemists. 

Application. — Several  most  beautiful  colors  for  dyeing  silk  have  been  prepared  by  Mr. 
William  H.  Perkin,  of  Greenford  Green,  near  Harrow,  from  certain  salts  of  aniline,  which 
arc  of  different  shades  of  violet,  some  more  approaching  purple,  others  more  pink.  They 
arc  now  being  extensively  employed  in  dyeing  silk,  and  are  found  to  be  far  finer  in  tint, 
and  more  permanent,  than  any  other  known  dyes  of  a  similar  color.  The  processes  for 
their  manufacture  have  been  patented  by  Mr.  Perkin.  For  the  following  short  description 
of  the  method  of  preparing  them,  we  are  indebted  to  that  gentleman  : — 

"  Take  equivalent  proportions  of  sulphate  of  aniline  and  bichromate  of  potash,  dissolve 
them  in  water,  mix,  and  allow  the  mixture  to  stand  for  several  hours.  The  whole  is  then 
thrown  upon  a  filter,  and  a  black  precipitate  which  has  formed  is  washed  and  dried.  It  is 
then  digested  with  coal-tar  naphtha,  to  extract  a  brown  resinous  substance,  and  finally 
digested  with  alcohol  to  dissolve  out  the  coloring  matter,  which  is  left  behind  on  distilling 
oft' the  spirit,  as  a  coppery  friable  mass." — H.  M.  W. 

ANISEED.  {Aids,  Fr.  ;  Anis,  Germ.)  The  fruit  or  seed  of  the  pinipincUa  anisum, 
largely  cultivated  in  Malta,  Spain,  and  Germany  ;  used  in  the  preparation  of  the  oil  of  anise, 
{oleum  anisi,)  the  spirit  of  anise,  {spi7\tus  anisi,)  and  anise  water,  {aqua  anisi.)  It  is  also 
used  in  cordials.  In  1855,  963  cwts.  were  imported.  The  oleum  badiani,  or  the  oil  of  star 
anise,  (jillicium  arrisatum,)  has  the  color  and  taste  of  the  oil  of  anise ;  but  it  preserves  its 
fluidity  at  35'6°  F.     It  is  sometimes  fraudulently  substituted  for  olcmn  anisi. — Pereira. 

ANTHRACITE.  {Uvdpa^,  coal.)  A  variety  of  coal  containing  a  larger  proportion  of 
carbon  and  less  bituminous  matter  than  common  coal. — De  la  Beche. 

Anthracite  coal  is  obtained  in  this  country,  at  Bideford,  in  Devonshire,  in  the  Western 
divisions  of  the  South  Wales  coal-field,  and  in  Ireland.  It  is  found  abundantly  in  America. 
Professor  H.  D.  Roger's  "  Transactions  of  American  Geologists  "  states  that  in  the  great 
Appalachian  coal-field,  extending  "720  miles,  with  a  chief  breadth  of  180  miles,  the  coal  is 
bituminous  towards  the  western  limit,  where  it  is  level  and  unbroken,  becoming  anthracitic 
towards  the  south-west,  where  it  is  disturbed.  Anthracitic  coal  is  also  found  in  the  coal- 
fields of  France,  especially  in  the  departments  of  Isere,  the  High  Alps,  Gard,  Mayeune,  and 
of  Sarth  ;  about  42,2'7 1,000  kilogrammes  (of  2'2046  avoirdupois  pounds  each)  are  produced 
annually.    Anthracite  is  also  raised  in  Belgium. 

Anthracite  is  not  an  original  variety  of  coal,  but  a  modification  of  the  same  beds  which 
remain  bituminous  in  other  parts  of  the  region.  Anthracite  beds,  therefore,  are  not  sepa- 
rate deposits  in  another  sea,  nor  coal  measures  in  another  area,  nor  interpolations  among 
I)ituminous  coals,  but  the  bituminous  beds  themselves,  altered  into  a  natural  coke,  from 
which  the  volatile  bituminous  oils  and  gases  have  been  driven  off. — J.  P.  Lesley,  on  Coal. 

Anthracite — now  extensively  used  for  iron-making,  steam-engines,  and  for  domestic  pur- 
poses, in  the  United  States — was,  some  50  years  since,  regarded  as  incombustible  refuse, 
and  thrown  away. 

This  peculiar  and  valuable  fossil  fuel  is  found  in  various  parts  of  the  old  and  new  con- 
tinent, as  shown  by  the  following  lists,  for  which  we  are  mainly  indebted  to  the  American 
publication.  Statistics  of  Coal,  by  Taylor. 

Localities  of  Anthracite  and  Anthracitous  Coal. 

VJJJiCWV  Specific  "Weight  of  a 

rj\ji\\ji  Ti.  Gravity.  cubic  yard  in  lbs. 

South  Wales :— Swansea 1-263  -  -  -  2,131 

Cyfarthfii l-33'7  -  -  -  2,256 

Yniscedwin 1.35i  -  -  -  2,284 

Average 1-445  -  -  -  2,278 

Ireland,  mean 1-445  -  -  -  2,376 

France  :—Allicr 1-380  -  -  -  2,207 

Tantal 1-390  -  -  -  2,283 

Brassac 1-430  -  -  -  2,413 

Belgium  :—Mons 1-307  -  -  -  2,105 

Westphalia 1.305  -  -  -  2,278 

Prussian  Saxony 1  -466  -  -  -  2,474 

Saxony          -    " 1-300  -  -  -  2,193 

Average  of  Europe     -    •    -        -         - 2,281 


ANTHRACITE. 


103 


Localities  of  Anthracite  and  Anthracitous  Coal,  (continued.) 

A  -WT^TJiri  A                                                                 Specific  Weight  of  a 

AJl£inii^A.                                                           Gravity.  cubic  yard  ia  Iba. 

Pennsylvania: — Lykens  Valley       -        -        -        -     1-327     -  -        -     2,240 

Lebanon  co.,  gray  vein          -         -     1-379     -  -         -     2,327 

Schuylkill  co.,  Lorberry  Creek       -     1-472     -  -         -     2,484 

Pottsville,  Sharp  Mountain    -         -     1-412     -  -         -     2,382 

Peach  -         -         -         -     1-44G     -  -         -     2,440 

"           Salem  Vein  -         -         -     1-574     -  -         -     2,049 

Tamaqua,  north  vein     -         -         -     1-000     -  -         -     2,700 

Mauch  Chunk        ...         -     1-550     -  -         -     2,615 

Nesquehoning       -         -         -         -     1-558     -  -         -     2,646 

WUkesbarre,  best          -         -         -     1-472     -  -         -     2,884 

WestMahoney     ...        -     1-371     -  -        -    2,313 

Beaver  Meadow    -        -        -        -     1-600     -  -        -     2,700 

GirardviUe I'GOO     -  -        -    2,700 

Hazelton 1-550     -  -         -     2,615 

Broad  Mountain   -        -        -        -     1-700    -  -        -    2,869 

Lackawanna           ....     1-609     -  -         -     2,715 

Massachusetts: — Mansfield 1-710     -  -        -    2,882 

Khode  Island :— Portsmouth            "         ■         "       ."     ^'^^^     '  '        '     ^'^^'* 
Average  in  United  States   ----------     2,601 

The  calorific  value  of  anthracite  coal  is  well  shown  by  the  following  results  from  Dr. 

Fyfe's  experiments  to  compare  Scotch  and  English  bituminous  coals  with  anthracite,  in  re- 
gard to  their  evaporative  power,  in  a  high-pressure  boiler  of  a  4-horse  engine,  having  a  grate 
with  8-15  square  feet  of  surface;  also  in  a  wagon-shaped  copper  boiler,  open  to  the  air, 
surface  18  feet,  grate  1-55. 


Kind  of  Fuel 

£  i 

it 

li 

Water  eva- 
from  the 
mperature 
of  Coal. 

Is 

afa  i 

is 

vaporated 
from  eacli 
Foot  of 
race. 

employed. 

•5    o 

§     U 

II 

1^ 
p. 

a 

Pounds  of 

porated 

initial  Te 

by  1  lb. 

p.  g « 

Pounds  e 

per  Hour 

Square 

Sur 

Kemarks, 

Middlerig  Scotch 

Pressure    17   lbs. 

coaL 

81-3.3 

9 

45' 

6  66 

7-74 

10-00 

44-27 

- 

per  sq.  inch. 

Scotch  coal,  dif- 

ferent   variety 

from  preceding 

108 

5 

ITO 

6  62 

6-89 

13-25 

33-33 

. 

Ditto. 

Anthracite  - 

47W 

Si 

45 

8-T3 

10-10 

5-88 

75  09 

- 

Ditto. 

Scotch  coal,  from 

near  Edinburgh 

3-24 

Si 

50 

5-38 

6-90 

5-31 

436-89 

3-15 

Lowpressnre,open 

English  bitumi- 

copper boiler. 

nous  coal. 

607 

8-4 

50 

7-84 

9-07 

8  91 

503-08 

3-06 

Ditto. 

Space  will  not  admit  of  our  entering  fully  into  the  question  of  the  evaporative  power  of 
anthracite ;  but  its  advantages  under  certain  conditions  are  fully  established. 

In  this  country  anthracite  coal  is  used  in  the  manufacture  of  iron  in  the  following  fur- 
naces : — 

Blast  Furnaces  making  Iron  from  Anthracite. 


No. 

Names  of  Works. 

Owners. 

Furnaces  built. 

Furnaces  in 
blast. 

Furnaces  in 
blast  in  Dis- 
trict. 

Glamokganshibe. 

1 

2 
3 
4 
5 

Aberdare,  Abernant,  and 

Llwydcoed 
Banwen       ... 
Onllwyn  or  Brln  . 
Venalt 
Tstalyfera    -       -        - 

Bekcknockshiee. 

Aberdare  Iron  Company 
Out  of  blast 

L.  Llewellyn      ... 
Aberdare  Iron  Company  - 
Ystalyfera  Iron  Company 

3 

2 
2 
2 

10 

8 
0 
1 

0 

7 

11 

1 
2 

Abercrave    ... 
Yniscedwin  ... 

C  AERM  AETHENSniEE. 

T.  -Walters 

Yniscedwin  Iron  Company 

1 
7 

1 
4 

6 

1 

2 
3 

Bryn  Ammon 

Gwendracth 

Trim  Saren  -       -       - 

PEMBEOKESniEE. 

L.  Llewellyn     ... 
T.  Watney  &  Co. 
E.  n.  Thomas    - 

2 
2 

2 

2 
1 
0 

8 

1 

Sandersfoot  - 

Pembroke  Iron  and  Coal  Co. 

1 

0 

0 

Total  furnace 

s  in  blast  in  anthracite  district 

s  in  1857 

-       • 

19 

104 


ANTELOPE  HOEN. 


Professor  W.  R.  Johnson,  of  Pennsylvania  College,  informs  us  that  fourteen  furnaces 
using  anthracite  for  the  production  of  iron  were  in  use  in  the  United  States. 
In  the  anthracite  districts  of  South  Wales,  the  produce  was,  in — 


1855 
1856 
1857 


997,500  tons. 
965,500     " 
1,485,000     " 


The  following  table  shows  the  progress  of  production  in  America  of  anthracite  from 
1840  to  1857,  inclusive,  from  Schuylkill,  Lehigh,  and  Wyoming : — 


Tear. 

Tons. 

Ipcrease  per  Tear. 
Tons. 

1840 

864,384 

45,982 

1841 

950,973 

86,589 

1842 

1,108,418 

157,445 

1843 

1,263,598 

155,180 

1844 

1,630,850 

367,252 

1845 

2,013,013 

382,163 

1846 

2,344,005 

330,992 

1847 

?,882,300 

538,595 

1848 

3,089,238 

206,938 

1849 

3,217,641 

128,403 

1850 

3,321,136 

103,495 

1851 

4,329,530 

1,008,394 

1852 

4,899,975 

570,445 

1853 

6,097,144 

197,169 

1854 

5,831,834 

734,690 

1855 

6,486,097 

654,263 

1856 

6,751,542 

265,445 

1857 

6,431,379 

320,163  decrease. 

Pottsville  Miners'  Journal. 

A  steady  increase  is  thus  shown  in  the  production  of  American  anthracite,  excepting 
during  the  last  year.  This  decrease  may  be  readily  accounted  for  by  the  general  depression 
of  the  iron  and  other  manufactures. 

The  annual  consumption  of  anthracite  in  the  United  States  was  thus  stated  in  the 
Science  of  New  York  Exhibitio7i : — 


1820 
1825 
1830 
1835 
1840 
1845 
1850 
1853 


about 


330  tons. 

35,000  " 

"      176,000  " 

"      561,000  " 

"      865,000  " 

"  2,023,000  " 

"   3,357,000  " 

"   5,195,000  " 


The  quantity  consumed  in  1856  is  stated  to  have  been  7,900,000  tons. 

ANTELOPE  HORN  is  used  occasionally  for  ornamental  knife  handles.     See  Horn. 

ANTICHLORE.  A  terra  employed  by  bleachers  to  the  means  of  obviating  the  perni- 
cious after-effects  of  chlorine  upon  the  pulp  of  paper,  or  stuffs,  which  have  been  bleached 
therewith.  Manufacturers  have  been  in  the  habit  of  using  sulphite  of  soda,  whose  action 
upon  the  adhering  bleaching  salt,  which  cannot  be  removed  by  washing,  gives  rise  to  the 
formation  of  sulphate  and  hydrosulphate  of  soda  and  chloride  of  sodium.  Chloride  of  tin 
has  been  recommended  bv  some  chemists  for  this  purpose. 

ANTI- ATTRITION,  or,  ANTI-FRICTION  COMPOSITION.  Tarlous  preparations  have 
been,  from  time  to  time,  introduced  for  the  purpose  of  removing,  as  much  as  possible,  tlie 
friction  of  machinery.  Black  lead,  or  plumbago,  mixed  with  a  tenacious  grease,  has  been 
much  employed.     Peroxide  of  iron,  finely  divided  haematite,  &c.,  have  also  been  used. 

A  composition  employed  at  Munich  is  reported  to  have  been  used  with  success  and 
economy  to  diminish  friction  of  machinery.  It  consists  of  ten  and  a  half  parts  of  pure  hogs' 
lard,  fused  with  two  parts  of  finely  pulverized  and  sifted  plumbago.  The  lard  is  first  to  be 
melted  over  a  moderate  fire,  then  a  handful  of  the  plumbago  thrown  in,  and  the  materials 
stirred  with  a  wooden  spoon  until  the  mixture  is  perfect ;  the  rest  of  the  plumbago  is  then 
to  be  added,  and  again  to  be  stirred  until  the  substance  is  of  uniform  composition ;  the  ves- 
sel is  then  to  be  removed  from  the  fire,  the  motion  being  continued  until  the  mixture  is 


ANTIMONY. 


105 


quite  cold.     The  composition,  in  its  cold  state,  was  applied  to  the  pivots,  the  teeth  of 
wheels,  &c.,  by  a  brush,  and  seldom  more  than  once  in  24  hours.* 

It  was  found  that  this  composition  replaced  the  oil,  tallow,  and  tar,  in  certain  iron  works 
with  economy,  saving  about  *ji  of  the  cost  of  these  articles. 

ANTI-FRICTIuN  METAL.  Tin  and  pewter  are  commonly  employed  as  anti-friction 
metals  for  the  bearings  of  locomotive  engines. 

Babbet's  metal  is  prepared  by  taking  about  fifty  parts  of  tin,  five  of  antimony,  and  one 
of  copper. 

Tin  or  pewter,  used  alone,  owing  to  its  softness,  spreads  out  and  escapes  under  the 
superincumbent  weight  of  the  locomotive,  or  other  heavy  machinerj'.  It  is  usual,  there- 
fore, to  add  antimony,  for  the  purpose  of  giving  these  metals  hardness. 

Fenton's  Anti-friction  metal,  which  is  much  employed,  is  a  mixture  of  tin,  copper,  and 
spelter.  Its  advantages  are  stated  to  be  cheapness  in  first  cost,  low  specific  gravity,  being 
20  per  cent,  lighter  than  gun  metal ;  and  being  of  a  more  unctuous  or  soapy  character  than 
gun  metal,  less  grease  or  oil  is  required. 

The  softer  metal  is  often  supported  by  brasses  cast  of  the  required  form,  the  tin  alloy 
being  cast  upon  them.  The  brasses,  or  bearings,  being  properly  tinned,  and  an  exact  model 
of  the  axle  having  been  turned,  the  parts  are  heated,  put  together  in  their  relative  positions, 
luted  with  plastic  clay,  and  the  fluid  anti-friction  metal  poured  in,  which  then  becomes  of 
the  required  form,  and  effectually  solders  the  brass. 

The  following  compositions  are  recommended  to  railway  engineers  as  having  been  em- 
ployed for  several  years  in  Belgium  : — In  those  cases  where  the  objects  are  much  exposed 
to  friction,  20  parts  of  copper,  4  of  tin,  0-5  of  antimony,  and  0-25  of  lead.  For  objects 
which  are  intended  to  resist  violent  shocks,  20  parts  of  copper,  6  of  zinc,  and  1  of  tin. 
For  those  which  are  exposed  to  heat,  17  parts  of  copper,  1  of  zinc,  0-5  of  tin,  and  0-25  of 
lead.     The  copper  is  added  to  the  fused  mass  containing  the  other  metals. 

ANTIMONY  occurs  with  numerous  ores  of  lead  and  silver,  of  nickel,  &c.,  but  the  most 
important  ore  of  antimony  is  the  sulphuret,  (Stibnite,  or  Gray  Antimony,)  which  forms  the 
chief  and  most  common  source  of  the  antimony  of  commerce,  and  of  the  greater  number 
of  the  pharmaceutical  preparations  of  that  metal.  Antimony  is  not  at  present  produced  in 
this  country,  but  in  the  last  century  it  was  mined  extensively. 

The  most  celebrated  localities  of  this  ore  are  Falsobanya,  Schemnitz,  and  Kremnitz,  in 
Hungary,  where  it  occurs  in  diverging  prisms  several  inches  long.  It  is  also  found  in  the 
Ilartz,  at  Andreasberg,  in  Hungary,  in  Cornwall,  at  the  old  Trewetha  mine,  and  abundantly 
in  Borneo. 

This  ore  was  called  by  the  ancients  iv\aTv6^QaKixov — ttAotus,  broad,  6<p6a\fi.hs,  e;/e — from 
the  use  to  which  it  was  applied  in  increasing  the  apparent  size  of  the  eye,  as  is  still  prac- 
tised among  oriental  nations,  by  staining  the  upper  and  under  edges  of  the  eyelids.  It  was 
also  used  as  a  hair-dye  and  to  color  the  eyebrows. 

It  was  the  Lupus  Metallorum  of  the  alchemists.  Crude  antimony  is  obtained  from  it  by 
simple  fusion,  and  from  this  product  the  pure  metal  is  extracted. 

The  other  principal  ores  of  antimony  are  the  following  : — 

Native  Antimony  is  a  mineral  of  a  tin-white  color  and  streak  and  a  metallic  lustre,  and 
sometimes  contains  silver,  iron,  and  arsenic,  with  which  last  it  is  commonly  associated.  It 
is  brittle,  and  possesses  a  specific  gravity  of  6-62  to  6-72.  It  is  generally  lamellar,  some- 
times botryoidal,  or  reniform.  Before  the  blowpipe  it  soon  melts,  and  continues  to  burn 
after  the  heat  is  removed  ;  but  if  the  heat  be  continued,  it  evaporates  in  white  fumes,  and  is 
redeposited  round  the  globule. 

Native  antimony  occurs  at  Sahlburg  in  Sweden,  Andreasberg  in  the  Hartz,  Allcmont  in 
Dauphiny,  in  Mexico,  &c. 

Arsenical  Antimony  also  occurs  at  Allemont,  in  the  Hartz,  and  elsewhere,  in  reniform 
and  amorphous  masses,  with  a  finely  granular  or  a  curved  lamellar  structure.  It  is  com- 
posed of  arsenic  62-15,  antimony  57'85.  It  possesses  a  metallic  lustre,  and  a  reddish-gray 
or  tin-white  lustre.     Its  specific  gravity  is  6'2. 

Oxide  of  Antimony  (Cervantite)  occurs,  associated  with  gray  antimony,  (of  which  it  is 
an  altered  form,)  at  Cervantes,  in  Spain,  in  Hungary,  and  the  Auvergnc.  It  is  found  in 
octahedral  crystals,  and  in  radiating  fibrous  crystals  in  the  province  of  Constantino,  in  Alge- 
ria, {Senarmontite,)  also  at  Perneck,  in  Hungary.  It  occurs  as  a  crust  or  ])owder,  or  in 
acicular  crystals,  with  a  greasy  or  earthy  lustre,  and  of  a  pale  yellow  or  nearly  white  color. 
Specific  gravity  =  40-8.  It  is  composed  of  antimony  80-1,  oxygen  l'.)-9  ;  Ijut  fre(iuently  it 
contains  an  admixture  of  iron,  carbonate  of  lime,  &c.     It  is  soluble  in  muriatic  acid. 

White  Antimony  [Valentinitc)  is  the  result  of  the  alteration  of  gray  antimony,  native 
antimony,  and  other  ores  of  that  metal.  It  possesses  a  shining  pearly  lustre  and  a  snow- 
white  color,  but  is  sometimes  pinkish,  or  ash-gray,  or  brownish.  It  ailbrds  a  white  streak. 
It  is  composed  of  antimony  84-32,  oxygcti  L^-tiS.  Specific  gravity  =  5-50.  It  is  found  in 
tabular  crystals  in  veins  traversing  the  primary  rocks  at  Prizbram  in  Bohemia,  eear  Frey- 
berg  in  Saxony,  Allemont  in  Dauphiny,  &c. 

*  Ann.  des  Mines,  xi.  79. 


lua 


ANTIMONY,  GLASS  OF. 


Red  Antimony  {Kermesite)  is  a  compound  of  oxide  of  antimonj'  30-2,  and  sulphide  of 
antimony  C9-8,  or  antinaony  74-45,  oxygen  5-29,  and  sulphur  20-49. 

It  occurs  generally  in  capillary  six-sided  prismatic  crystals  of  a  cherry-red  color,  afford- 
m"  a  brownish-red  streak.     It  has  a  specific  gravity  of  from  4-5  to  4-6. 

"  It  is  feebly  translucent,  and  possesses  an  adamantine  lustre.     It  occurs  at  Walaczka  in 
Hungary,  Braunsdorf  in  Saxony,  and  at  AUemout  in  Dauphiny. 

At  Malboac,  in  the  department  of  Ar- 
d^che,  in  France,  the  separation  of  the  sulphide 
of  antmiony  from  its  associated  gangue  is 
effected  by  means  of  a  peculiar  apparatus,  {Jig. 
39.)  The  mineral  is  placed  in  large  retorts, 
R  R,  of  which  four  are  set  in  each  furnace. 
An  aperture  is  left  at  the  bottom  of  each  of 
these  cylinders,  which  corresponds  with  a  sim- 
ilar opening  by  which  they  are  supported. 
Beneath  these,  in  the  chambers  c  c,  are  placed 
earthen  pots,  p  p,  in  which  is  received  the 
melted  sulphide  as  it  descends  through  the 
openings  in  the  cylinders.  The  fuel  consumed 
on  the  grate  consists  of  fir  wood  ;  and  the  sul- 
phide obtained  is  converted  into  metallic  anti- 
mony by  roasting  in  a  reverberatory  furnace, 
and  subsequent  reduction  by  a  mixture  of  20 
per  cent,  of  powdered  charcoal  which  has 
been  saturated  with  a  strong  solution  of  the 
carbonate  of  soda. 

Melted  with  tin,  antimony  has  of  late  been  used  as  an  anti-friction  alloy  for  railway 
axles,  and  other  bearings  ;  in  metallic  rings,  or  collars,  for  machinery.  As  this  alloy  is  not 
so  much  heated  by  friction  as  the  harder  metals,  less  grease  is  consumed. 

ANTIMONY,  GLASS  OF.     This  substance,  according  to  M.  Soubeiran,  contains — 
Protoxide  of  antimony    -         -         -         -         -         -         -         -         -91-5 

Silica 4-5 

Peroxide  of  iron 3"2 

Sulphuret  of  antimony 1-9 

101-1 

APPLE  WIXE.  Cider.  Winckler  finds  that  the  wine  from  apples  is  distinguished 
from  the  wine  from  grapes  by  the  absence  of  bitartrate  of  potash  and  of  a^nanthic  acid,  by 
its  containing  a  smaller  amount  of  alcohol  and  more  tannin,  but  especially  by  the  presence 
of  a  characteristic  acid,  which  he  regards  as  lactic  acid,  notwithstanding  that  this  opinion  is 
not  confirmed  by  the  degree  of  solubility  of  its  salts  with  oxide  of  zinc,  lime,  and  magnesia. 
See  Cider,  vol.  i.,  p.  561. 

AQUAFORTIS.  This  acid  has  usually  been  obtained  by  mixing  common  nitre  with 
green  vitriol  or  sulphate  of  iron,  and  distilling,  or  by  mixing  nitre  and  clay  or  siliceous 
matter,  and  distilling  over  the  nitric  acid,  leaving  the  alkali  to  unite  with  the  earthy  base. 

It  may,  however,  be  usefully  borne  in  mind,  that  this  term  of  aquafortis^  or  strong 
icatcr  of  the  old  chemist,  was  also  applied  to  solutions  which  answered  their  special  pur- 
poses. Thus  Salmon,  in  1685,  gives  the  composition  of  aquafortis  from  certain  mixtures 
of  acids,  not  nitric,  and  salts,  and  distinctly  refers  to  the  Pharmacopoeia  for  the  other  kind. 
This  may  be  of  service  when  applying  old  recipes  for  processes  in  the  arts.  Aquafortis  did 
not  always  mean  nitric  acid.     See  Nitric  Acid. 

AQUAMARINE  is  the  name  given  to  those  varieties  of  beryl  which  are  of  clear  shades 
of  sky-blue  or  greenish-blue,  like  the  sky.  It  occurs  in  longitudinally-striated  hexagonal  crys- 
tals, sometimes  a  foot  long,  and  is  found  in  the  Brazils,  Hindostan,  and  Siberia.     See  Beryl. 

AQUA  REGIA.  Royal  water.  Now  called  nitro-muriatic  acid,  or  nitro-eJilorohydric 
acid,  or  hypochloro-vitric  acid. 

Prepared  under  different  conditions,  it  appears  to  give  different  results.  Gay-Lussac 
observed  that  aqua  regia.  when  heated  in  a  water-bath,  evolves  a  gaseous  body  which,  dried 
and  exposed  to  a  frigorific  mixture,  separates  into  chlorine  and  a  dark  lemon-yellow  liquid, 
boiling  at  70"  F.  This  yellow  liquid  was  found  to  contain  69-4  per  cent,  of  chlorine,  the 
calculated  quantity  for  the  formula,  NO'Cl-,  being  70-2.  Gay-Lussac  refutes  the  assertion 
of  E.  Davy  and  Baudrimont,  that  the  properties  of  aqua  regia  are  due  to  its  containing  a 
compound  of  chlorine,  nitrogen,  and  oxygen,  and  confirms  the  generally  received  view,  that 
its  action  depends  upon  free  chlorine.  From  the  vapor  evolved  in  the  action  of  aqua  regia 
upon  gold,  a  liquid  may  be  condensed  which  is  nearly  of  the  composition  NO'^CF,  contain- 
ing, however,  no  free  chlorine. 

ARABIC,  GUM.  Chemists  have  been  disposed  to  divide  gums  into  three  varieties,  to 
which  they  have  given  the  names  of  Arabine,  ccrasine,  and  dextrine. 


ARCHIL. 


107 


Arabine,  or  gum  Arabic,  exudes  from  several  species  of  acacia  and  prunus ;  it  is  al60 
found  in  the  roots  of  the  mallow,  comfrey,  and  some  other  plants.  Gum  Arabic  never  crys- 
tallizes, is  transparent,  and  has  a  vitreous  fracture.  It  dissolves  in  water  in  all  proportions, 
forming  inucilaffe.     Its  chemical  composition  is  expressed  by  the  fornmla,  C'"H"0". 

ARCH.  As  this  dictionary  is  not  intended  to  include  articles  connected  with  engineering 
or  with  architecture,  it  would  be  out  of  place  to  describe  the  conditions  required  to  ensure 
the  stability  of  the  arch,  which  is  manifestly  one  of  great  importance  to  the  practical  builder. 
(For  the  theory  of  the  equilibrium  of  the  arch,  Gwilt's  treatise  on  the  subject  should  be  con- 
sulted, or  the  article  Arch,  "  Encyclopaedia  Britannica.") 

ARCHIL.  {Orseille,  Fr.  ;  Orseille,  Germ.  ;  Oi-icello,  Ital.)  The  name  of  archil  is 
given  to  a  coloring  matter  obtained,  by  the  simultaneous  action  of  the  air,  moisture,  and  an 
ammoniacal  liquor,  from  many  of  the  lic/ie?is,  the  most  esteemed  being  the  lichen  roccella. 

It  appears  in  commerce  in  three  forms:  1,  As  a  pasty  matter  called  archil ;  2,  as  a 
mass  of  a  drier  character,  wdiUied  perxis ;  and  3,  as  a  reddish  powder  called  cudbear. 

The  lichen  from  which  archil  i.s  prepared  is  known  also  as  the  canary  weed  or  orchilla 
weed.  It  grows  in  great  abundance  on  some  of  the  islands  near  the  African  coast,  particu- 
larly in  the  Canaries  and  several  of  the  Islands  of  the  Archipelago.  Its  color  is  sometimes 
a  light  and  sometimes  a  dark  gray. 

The  chemical  constitution  of  archil  was  first  investigated  by  M.  Cocq,  "  Annales  de 
Chimie,"  vol.  Ixxxi. ;  and  subsequently,  yet  more  extensively,  by  Robiquet,  "  Annales  de 
Chimie,"  vol.  xlii.,  2d  series. 

From  the  Variolaria,  Robiquet  obtained  Orcine,  by  digesting  the  lichen  in  alcohol, 
evaporating  to  dryness,  dissolving  the  extract  in  water,  concentrating  the  solution  to  the 
thickness  of  a  syrup,  and  setting  it  aside  to  crystallize.  It  forms,  when  quite  pure,  color- 
less prisms,  of  a  nauseous  sweet  taste,  which  fuse  easily,  and  may  be  sublimed  unaltered. 
Its  formula  is  C'"HO*  -[-  3Aq.  when  sublimed  ;  when  crystallized  from  its  aqueous  solution 
it  contains  5  Aq. 

If  orcine  be  exposed  to  the  combined  action  of  air  and  ammonia,  it  is  converted  into  a 
crimson  powder  orc'eine,  which  is  the  most  important  ingredient  in  the  archil  of  commerce. 
Orceine  may  be  obtained  by  digesting  dried  archil  in  strong  alcohol,  evaporating  the  solu- 
tion in  a  water-bath  to  dryness,  and  treating  it  with  ether  as  long  as  any  thing  is  dissolved  ; 
it  remains  as  a  dark  blood-red  powder,  being  sparingly  soluble  in  water  or  ether,  but  abun- 
dantly in  alcohol.     Its  formula  is  C'H'NO'. 

Orceine  dissolves  in  alkaline  liquors  with  a  magnificent  purple  color ;  with  metallic 
oxides  it  forms  lakes,  also  of  rich  purple  of  various  shades.  In  contact  with  deoxidizing 
agents,  it  combines  with  hydrogen,  as  indigo  does,  and  forms  leuc-orceine,  C^ffNO'  -(-  II. 
When  bleached  by  chlorine,  a  yellow  substance  is  formed,  cA^or-orceine,  the  formula  of 
which  is  C'^H'^XO'  -j-  CI  analogous  to  the  other. — Kane. 

Dr.  Schunk,  by  an  examination  of  several  species  of  Lecanora,  has  proved  that,  although 
under  the  influence  of  ammonia  and  of  air,  they  ultimately  produce  orceine,  these  lichens 
do  not  contain  orcine  ready  formed,  but  another  body,  Lecanorine,  which,  under  the  influ- 
ence of  bases,  acts  as  an  acid,  and  is  decomposed  into  orcine,  and  carbonic  acid.  If 
lecanoric  acid  be  dissolved  in  boilin:^  alcohol,  it  unites  with  ether,  forming  lecanoric  ether, 
which  crystallizes  beautifully  in  pearly  scal^.  In  the  roccella  tinctoria  and  the  everma 
pruna^tri,  erytheric  acid  is  found.  By  the  oxidation  of  this  acid  amarythrine  or  erythrine 
bitter  is  formed.  These  substances  have  been  carefully  examined  by  Schunk,  Stcnhouse, 
and  Kane.  The  chemical  history  of  these  and  some  other  compounds  is  of  great  interest ; 
but  as  they  do  not  bear  directly  upon  the  manufacture  of  archil,  or  its  use  in  dyeing,  fur- 
ther space  cannot  be  devoted  to  their  consideration. 

Kane  found  archil  and  litmus  of  commerce  to  contain  two  classes  of  coloring  matters, 
as  already  stated,  orcine  and  orceine,  derived  from  it.  Beyond  these  there  were  two  bodies, 
one  containing  nitrogen,  ar.oerythrine,  and  the  other  destitute  of  nitrogen,  erythrolcic  acid. 
This  latter  acid  is  separated  from  the  other  bodies  present  in  archil  by  means  of  ether,  in 
which  it  dissolves  abundantly,  forming  a  rich  crimson  solution.  It  gives  with  alkalies 
purple  liquors,  and  with  earthy  and  metallic  salts  colored  lakes. 

Beyond  those  already  named  there  are  several  other  species  of  lichen  which  might  be 
employed  in  producing  an  analogous  dye,  were  they  prepared,  like  the  preceding,  into  the 
substance  called  archil.  Ilellot  gives  the  following  method  for  discovering  if  they  possess 
this  property  : — A  little  of  the  plant  is  to  be  put  into  a  glass  vessel ;  it  is  to  be  moistened 
with  ammonia  and  lime-water  in  equal  parts  ;  a  little  muriate  of  ammonia  (sal  ammoniac)  is 
aflded,  and  the  small  vessel  is  corked.  If  the  plant  be  of  a  nature  to  afford  a  red  dye,  after 
three  or  four  days  the  small  portion  of  liquid  which  will  run  off.  on  inclining  the  vessel, 
now  opened,  will  Ije  tinged  of  a  crimson  red,  and  the  plant  itself  will  have  assumed  this 
color.  If  the  liquor  or  the  plant  does  not  take  this  color,  nothing  need  be  hoped  for ;  and 
it  is  useless  to  attempt  its  preparation  on  the  great  scale.  Lewis  says,  however,  that  he  has 
tested  in  this  way  a  great  many  mosses,  .and  that  most  of  them  afforded  him  a  yellow  or 
reddish-brown  color;  but  that  he  obtained  from  only  a  small  number  a  li(iuor  of  a  deep  red, 
whicli  communicated  to  cloth  merely  a  yellowish-red  color. 


108  AREOMETEE. 

To  prepare  archil,  the  lichens  employed  are  ground  up  with  water  to  a  uniform  pulp, 
and  this  is  then  mixed  with  as  much  water  as  will  make  the  whole  fluid  ;  ammoniacal  liquors 
from  gas  or  from  ivory-black  works,  or  stale  urine,  are  from  time  to  time  added,  and  the 
mass  frequently  stirred  so  as  to  promote  the  action  of  the  air.  The  orcine  or  erythrinc 
which  exists  in  the  lichen  absorbs  oxygen  and  nitrogen,  and  forms  orceine.  The  roccelline 
absorbs  oxygen  and  forms  erythrolcic  acid ;  these  being  kept  in  solution  by  the  ammonia,  the 
whole  liquid  becomes  of  an  intense  purple,  and  constitutes  ordinary  archil. — Kane. 

Tiie  herb  archil,  just  named,  culled  especially  orclil/e  de  ierre,  is  found  upon  the  vol- 
canic rocks  of  the  Auvcrgne,  on  the  Alps,  and  the  Pyrenees. 

These  lichens  arc  gatliered  by  men  whose  whole  time  is  thus  occupied  ;  they  scrape  them 
from  the  rocks  with  a  peculiarly  shaped  knife.  They  prefer  collecting  the  orceille  in  rainy 
weather,  when  they  are  more  easily  detached  from  the  rocks.  They  gather  about  2  kilo- 
grammes a  day,  or  about  4i  pounds.  When  they  take  their  lichens  to  the  makers  of  archil 
or  litmus  for  the  purpose  of  selling  them,  they  submit  a  sample  to  a  test,  for  the  purpose 
of  estimating  their  quality.  To  this  end  they  put  a  little  in  a  glass  containing  some  urine, 
with  a  small  quantity  of  lime.  As  the  lichens  very  rapidly  pass  into  fermentation  if  kept  in 
a  damp  state,  and  thus  lose  much  of  their  tinctorial  power,  great  care  is  taken  in  drying 
them  ;  when  dry  they  may  be  preserved  without  injury  for  some  time. 

AREOMETER.  An  instrument  to  measure  the  densities  of  liquids.  (Sec  Alcoholom- 
ETRY.)  The  ])rinciple  will  be  well  understood  by  remembering  that  any  solid  body  will  sink 
further  in  a  light  liquid  than  in  a  heavy  one.  The  areometer  is  usually  a  glass  tube,  having 
a  small  glass  bulb  loaded  with  either  shot  or  quicksilver,  so  as  to  set  the  tube  upright  in  any 
fluid  in  which  it  will  swim.  Within  the  tube  is  placed  a  graduated  scale  :  we  will  suppose 
the  tube  placed  in  distilled  water,  and  the  line  cut  by  the  surface  of  the  fluid  to  be  marked  ; 
that  it  is  then  removed  and  placed  in  strong  alcohol — the  tube  will  sink  much  lower  in  this, 
and  consequently  we  shall  have  two  extremities  of  an  arbitrary  scale,  on  which  we  can  mark 
any  intermediate  degrees. 

ARNATTO,  or  ARNOTTO.  See  Annotto,  vol.  i.  Arnatto  was  considered  to  contain 
two  distinct  coloring  matters,  a  yellow  and  red,  till  it  was  shown  by  M.  Pressier  that  one  is 
the  oxide  of  the  other,  and  that  they  may  be  obtained  by  adding  a  salt  of  lead  to  a  solution 
of  arnatto,  which  precipitates  the  coloring  matter.  The  lead  is  separated  by  sulphuretted 
hydrogen  ;  and  the  substance  beijig  filtered  and  evaporated,  the  coloring  matter  is  deposited 
in  small  crystals  of  a  yellow-white  color.  These  crystals  consist  of  bixine ;  they  become 
yellow  by  exposure  to  the  air,  but  if  they  are  dissolved  in  water  they  undergo  no  change. 
When  ammonia  is  added  to  bixine^  with  free  contact  of  air,  there  is  formed  a  fine  deep  red 
color,  like  arnatto,  and  a  new  substance,  called  bixehie,  is  produced,  which  does  not  crys- 
tallize, but  may  be  obtained  as  a  red  powder ;  this  is  colored  blue  by  sulphuric  acid,  and 
combines  with  alkalies,  and  is  bixine  with  addition  of  oxygen.  When  arnatto,  in  the  form 
of  paste,  is  mixed  from  time  to  time  with  stale  urine,  it  appears  probable  that  the  improve- 
ment consists  in  the  formation  of  bixeine  from  the  bixine  by  the  ammonia  of  the  urine.  It 
has  hence  been  suggested  that,  to  improve  the  color  of  arnatto,  it  might  be  mixed  with  a 
little  ammonia,  and  subsequently  exposed  to  the  air,  previously  to  its  being  used  for  dyeing. 

A  solution  of  arnatto  and  potash  in  water  is  sold  under  the  name  of  ScotCs  Nankeen 
Dye.  y 

ARROBA  (of  wine).     A  Spanish  measure,  equal  to  S'SSl*/  gallons. 

ARROW  ROOT.  In  commerce,  the  term  arrow  root  is  frequently  used  generically  to 
indicate  a  starch  or  fecula,  as  Portland  arroio  root,  a  white  amj'laccous  powder,  prepared 
in  the  Isle  of  Portland,  from  the  Aruin  vnlyare,  the  common  Cuckoo-pint,  called  also  Wake- 
robin  and  Lords  and  Ladies. 

East  India  ar,  ow  root,  prepared  from  the  Cnrcnina  angustifolia. 

Brazilian  arrow  root,  the  fecula  of  Jatroplta  inanihot. 

Encflish  arrow  root,  the  starch  of  the  potato. 

Tahiti  arrow  root,  the  fecula  of  Tacca  occanica,  which  is  imported  into  London  and  sold 
as  "  arrow  root  prepared  by  the  native  converts  at  the  missionary  stations  in  the  South  Sea 
Islands." 

ARSENIC,  derived  from  tlic  Greek  apcreviKov,  mascnlinc,  applied  to  orpiments  on  ac- 
count of  its  i)otent  powers.  This  metal  occurs  native  in  veins,  in  crystalline  rocks,  and  the 
ohler  schists  ;  it  is  found  in  the  state  of  oxide,  and  also  combined  with  sulphur  under  the 
improper  name  of  yellow  and  red  arsenic,  or  orpiment  and  realgar.  Arsenic  is  associated 
witli  a  great  many  metallic  ores  ;  l)ut  it  is  chiefly  extracted  in  this  country  from  those  of  tin, 
by  roasting,  in  which  case  the  white  oxide  of  arsenic,  or,  more  correctly,  the  arsenious  acid 
is  obtained.     On  the  Continent,  arsenical  cobalt  is  the  chief  source  of  arsenic. 

The  following  are  the  principal  ores  of  arsenic  : — 

Katire  Arsenic. — The  mo.st  common  form  of  native  arsenic  is  reniform  and  stalactitic 
mas.ses,  often  manimillated,  and  splitting  off  in  thin  successive  layers  like  those  of  a  shell. 
It  possesses  a  somewhat  metallic  lustre,  and  a  tin-white  color  and  streak,  which  soon  tar- 
nishes to  a  dark  gray.     Its  spewfic  gravity  is  5 '93.     Before  the  blow-pipe  it  gives  out  an 


AKSENIOUS  ACID. 


109 


alliaceous  odor,  and  volatilizes  in  white  fumes.    It  is  found  in  the  Hartz,  in  Andreasberg,  at 
the  silver  mines  of  Freiberg,  in  Chili,  the  Asturias,  &c. 

White  Arsenic,  or  Araenious  Arid,  .{Arsenolite,)  is  often  formed  by  the  decomposition 
of  other  arsenical  ores,  and  is  composed  of  arsenic  65-76  and  oxygen  24-24.  It  occurs  either 
in  minute  radiating  capillary  crystals  and  crusts  investing  other  substances,  or  in  a  stalactitic 
or  botryoidal  form.  Before  the  blow-pipe  it  volatilizes  in  white  fumes  ;  in  the  inner  flame 
it  blackens  and  gives  out  an  alliaceous  odor ;  its  specific  gravity  is  3-69.  It  is  white,  some- 
times with  a  yellowish  or  reddish  tinge,  and  has  a  silky  or  vitreous  lustre.  It  possesses  an 
astringent,  sweetish  taste. — H.  W.  B. 

Realgar,  (ancienty  called  Sandaraca,)  red  orpiment,  or  ruby  sulphur,  is  a  sulphide  of 
arsenic,  having  a  composition,  sulphur  29-91,  arseuic  '70-09.  It  occurs  in  Hungary,  Saxony, 
and  Switzerland. 

Orpiment,  (a  corruption  of  its  Latin  name,  auric/mentum — golden  paint,)  yellow  sulphide 
of  arsenic :  its  composition  is,  sulphur  39,  arsenic  61.  Burns  with  a  blue  flame  on  char- 
coal, and  emits  fumes  of  sulphur  and  arsenic.  Dissolves  in  nitromuriatic  acid  and  am- 
monia. 

Both  realgar  and  orpiment  are  artificially  prepared  and  used  as  pigments.  See  those 
articles. 

Arsenic  is  a  brittle  metal,  of  an  iron-gray  color,  with  a  good  deal  of  brilliancy.  It  may 
be  prepared  by  triturating  arsenious  acid,  or  the  white  arsenic  of  commerce,  with  black  flux, 
(charcoal  and  carbonate  of  potash,)  and  subliming  in  a  tube.  If  arsenical  pyrites  are  ignited 
in  close  tubes,  metallic  arsenic  sublimes,  and  sulphuret  of  iron  remains.  This  metal,  when 
exposed  in  the  air,  gradually  absorbs  oxygen,  and  falls  into  a  gray  powder,  (suboxide.)  This 
is  sold  on  the  Continent  as  fly  poivder. 

To  prepare  arsenic  on  a  larger  scale,  inispickcl,  or  the  other  ores  employed,  are  pounded; 
some  pieces  of  old  iron  are  mixed  with  the  ore,  to  retain  the  combined  sulphur,  and  the 
mixture  placed  in  retorts  between  four  and  five  feet  in  length,  to  which  receivers  are 
adapted.  The  retorts  are  moderately  heated  by  a  fire  placed  beneath  them  ;  the  ores  are 
decomposed,  and  metallic  arsenic  is  sublimed  and  condensed  in  the  receivers.  TJie  arsenic 
obtained  in  this  way  is  purified  by  a  second  distillation  with  a  little  charcoal. 

Arsenic  is  used  in  small  quantities  in  the  preparation  of  several  alloys ;  it  is  employed 
in  the  manufacture  of  opal  glass ;  also  is  much  used  in  the  manufacture  of  shot,  to  which  it 
imparts  a  certain  degree  of  hardness  ;  and,  by  preventing  the  distortion  of  the  falling  drops 
of  metal,  and  thus  securing  regular  globules,  the  manufacture  is  greatly  facilitated. 

ARSENIOUS  ACID,  White  Arsenic,  Flowers  of  Arsenic— t\\\s  is  the  white  arsenic  of 
commerce,  usually  called  Arsenic.  It  is  obtained  in  this  country  from  the  arsenical  ores  of 
iron,  tin,  &c.,  and  on  the  Continent  from  those  of  cobalt  and  nickel.  It  is  prepared  by 
heating  the  ores  containing  arsenic  on  the  sole  of  a  reverberatory  furnace,  through  which  a 
current  of  air,  after  passing  through  the  grate,  is  allowed  to  play.  The  following  ores  are 
the  more  remarkable  of  this  class, — the  quantity  of  arsenic  in  100  grains  is  given  in  each 
case : — 


Mispickel,  or  arsenical  iron  ... 
Lolingite,  arsenical  pyrites  -  -  . 
Kupfernickel,  arsenical  nickel 
Rnnunelsbergite,  white  arsenical  nickel  - 
Smnlline,  tin-white  cobalt  ... 
Sajflorite,  arsenical  cobalt        ... 


42-88 
65-88 
Sl-'TS 
72-64 
74-22 
70-37 


In  the  roasting  of  tin  ores,  a  considerable  quantity  of  arsenious  acid  is  collected  in  the 
flues  leading  from  the  furnaces  in  which  this  process  is  effected. 

White  arsenic  is  extensively  used  in  the  preparation  of  various  pigments,  as  the  bisul- 
phide, or  realgar,  the  tersulphidc,  or  orpiment,  and  also  in  the  mineral  greens  used  by 
paper-stainers.  It  is  employed  in  glass  and  porcelain  manufiicture.  Considerable  discus- 
sion has  arisen  from  a  statement  made  by  Mr.  A.  S.  Taylor,  that  the  arsenic  employed  in 
paper-hangings  was  removed  at  the  ordinary  temperatures  of  our  rooms,  and  that  many 
injurious  effects  had  resulted  from  the  use  of  such  paper.  Although,  under  some  circmn- 
stanccs,  it  is  possible  that  portions  of  the  arsenic  may  escape  as  dust  from  the  wall  of  a 
room,  experience  appears  against  its  exerting  any  injurious  effects.  Even  the  men  em{)l<)ycd 
in  burning-houses,  where  they  are  necessarily  exposed  to  the  escaping  oxide,  do  not  appear 
to  suffer  in  health.  The  following  letter,  published  by  Mr.  Alfred  E.  Fletcher,  is  much  to 
'the  point : — 

"  The  color  principally  referred  to  is  the  acoto-arsenite  of  copper,  commercially  known 
as  emerald  green.  The  chief  advantage  which  this  color  possesses  over  other  of  a  similar 
tint  is  that,  besides  having  greater  brilliancy,  it  is  quite  permanent.  The  color,  when  ex- 
posed to  the  air  for  any  length  of  time,  does  not  fade  in  tint  nor  lessen  in  intensity,  which 
would  necessarily  be  the  case  did  any  evaporation  of  its  constituent  parts  take  place,  thouijh 
in  the  smallest  degree,  especially  as  the  layer  of  color  exposed  is  often  extremely  thin. 


110  ARSENIOUS  ACID. 

Were  it  true  that  such  evaporation  or  dissemination  went  on,  it  would  indeed  afford  just 
cause  of  alarm,  when  we  reflect  that  on  the  walls  of  houses  in  this  country  are  displayed 
somejmndred  millions  of  square  yards  of  paper,  most  of  which  carries  on  its  surface  a  por- 
tion of  arsenical  coloring;  matter ;  our  books  are  bound  with  paper  and  cloth  so  colored, 
cottons  and  silks,  woollen  fabrics  and  leather,  are  alike  loaded  with  it.  Now,  it  is  stated 
that  ill  a  medical  work  an  instance  is  noted  in  which  injury  has  been  received  by  those  liv- 
ing in  rooms  decorated  with  these  colors  :  surely,  were  the  proximity  of  suchnnaterials  inju- 
rious, it  would  not  be  necessary  to  search  in  recondite  books  for  the  registry  of  isolated 
cases.  The  fact  of  the  large  extent  to  which  such  materials  have  always  been  employed  is 
a  sufficient  proof  that  there  is  no  danger  attending  their  use ;  moreover,  workmen  who 
have  been  daily  employed  for  many  years  in  manufacturing  large  quantities  of  these  colors, 
under  the  necessity  of  constantly  handling  them,  are  in  the  regular  enjoyment  of  perfect 
health,  though  exposed  also  to  the  general  influences  of  a  chemical  factory.  Let  blame  be 
laid  at  the  right  door,  and  let  the  public  be  assured  that  it  is  not  the  looking  at  cheerful 
walls,  the  fingering  of  brightly  ornamented  books,  nor  the  wearing  of  tastefully  colored 
clothing,  that  will  hurt  them,  but  the  dwelling  in  ill-ventilated  rooms." 

Aksenic,  Poisoning  bv. — This  poisoning  is  so  commonly  the  cause  of  death,  by  acci- 
dent and  by  design,  that  it  is  important  to  name  an  antidote  which  has  been  employed  with 
very  great  success. 

This  is  the  /ii/dratcd  peroxide  of  iron.  This  preparation  has  no  action  on  the  system, 
and  it  may  therefore  be  administered  as  largely  and  as  quickly  as  possible.  The  following 
statement  will  render  the  action  of  this  hydrated  salt  intelligible.  When  hydrated  peroxide 
of  iron  is  mixed  in  a  thin  paste  with  the  solution  of  arsenious  acid,  this  disappears,  being 
changed  into  arsenic  acid,  (a  far  less  active  oxide,)  and  the  iron  into  protoxide  2  Fe'C  and 
AsO',  producing  4  FeO  -[-  A^0°.  The  hydrated  peroxide  of  iron  may  be  made  in  a  few  min- 
utes by  adding  carbonate  of  soda  to  any  salt  of  the  red  oxide  of  iron,  (permuriate,  muriate, 
acetate,  &c.)  It  need  not  be  washed,  as  the  liquor  contains  only  a  salt  of  soda,  which  would 
be,  if  not  beneficial,  certainly  not  injurious. — Kane. 

Detection  of  Arsenic  in   Cases  of  Poisoning. 

Arsenious  acid,  which  is  almost  always  the  form  in  which  the  arsenic  has  entered  the 
system,  possesses  the  power  of  preventing  the  putrefaction  of  animal  substances ;  and 
hence  the  bodies  of  persons  that  have  been  poisoned  by  it  do  not  readily  putrefy.  The 
arsenipus  acid  combines  with  the  fatty  and  albuminous  tissues  to  form  solid  compounds, 
which  are  not  susceptible  of  alteration  under  ordinary  circumstances.  It  hence  has  fre- 
quently occurred  that  the  bodies  of  persons  poisoned  by  arsenic  have  been  found,  long  after 
di>ath,  scarcely  at  all  decomposed  ;  and  even  where  the  general  mass  of  the  body  had  com- 
pletely disappeared,  the  stomach  and  intestines  had  remained  preserved  by  tlie  arsenious 
acid  which  had  combined  with  them,  and  by  its  detection  the  crimes  committed  many  years 
before  have  been  brought  to  light  and  punished. — Kane. 

The  presence  of  arsenic  may  be  determined  by  one  of  the  following  methods : — 

1.  Portions  of  the  contents  of  the  stomach  or  bowels  being  gently  heated  in  a  glass  tube, 
open  at  both  ends,  the  arsenic,  if  in  any  quantity,  will  be  sublimed,  and  collected  as  minute 
brilliant  octahedrons. 

2.  Or  by  the  presence  of  organic  matter ;  if  the  ignition  is  effected  in  a  tube  closed  at 
one  end,  metallic  arsenic  sublimes,  forming  a  steel-gray  coat,  and  emitting  a  strong  smell 
of  garlic. 

3.  Ammonia  Nitrate  of  Silver  produces  a  canary -yellow  precipitate  from  a  solution  of 
arsenious  acid,  (arscnitc  of  silver.)  The  phosphate  of  soda  produces  a  yellow  precipitate 
of  tribasic  phosphate  of  silver,  which  exactly  resembles  the  arsenite.  The  phosphate  is, 
however,  the  more  soluble  in  ammonia,  and  when  heated  gives  no  volatile  product ;  while 
the  arsenite  is  decomposed  with  white  arsenic  and  oxygen,  leaving  metallic  silver  behind. 

4.  Ammonia  Sulphate  of  Copper  produces  a  fine  apple-green  precipitate,  which  is  dis- 
solved in  an  excess  of  either  acid  or  ammonia.  It  is,  however,  uncertain,  unless  the  pre- 
cipitate be  dried  and  reduced. 

5.  T7ie  lieduction  Test. — Any  portion  of  the  suspected  matter,  being  dried,  is  mixed 
with  equal  parts  of  cyanide  of  pota-sium  and  carbonate  of  potash,  both  dry.  This  mixture 
is  to  be  introduced  into  a  tube  terminating  in  a  bulb,  to  yhich  heat  is  applied,  when  metallic 
arsenic  sublimes. 

(i.  Mnrx}i\'i  Teat. — This  is  one  of  the  most  delicate  and  useful  of  tests  for  this  poison, 
and  when  performed  with  due  care  there  is  little  liability  to  error.  The  liquid  contents  of 
the  stomacli,  or  any  solution  obtained  by  boiling  the  contents,  is  freed  as  much  as  possible 
from  animal  matter  by  any  of  the  well-known  methods  for  doing  so.  This  fluid  is  then  ren- 
dered moderately  acid  by  sulphuric  acid,  and  introduced  into  a  bottle  properly  arranged. 

Fig.  40  is  the  best  form  for  Marsh's  apparatus  : — a  is  a  bottle  capable  of  holding  half, 
or,  at  most,  a  pint.  Both  necks  are  fitted  with  new  perforated  corks,  which  must  be  per- 
fectly tight.     Through  one  of  these  the  funnel  tube,  b,  is  passed  air-tight,  and  through  the 


ARSENIOUS  ACID.  Ill 

other  the  bent  tube,  c,  which  is  expanded  at/  into  a  bulb  about  an  inch  in  diameter.     This 

bulb  serves  to  collect  the  particles  of  liquid  which  are  thrown  up  from  the  contents  of  the 

bottle,  and  which  drop  again  into 

the  latter  from  the   end   of  the 

tube.     The  other  end  of  the  tube 

is  connected,  by  means  of  a  cork,  ,-  -^^ —  Q- 


40 


with  tube  </,  about  six  inches  long, 
which  is  filled  with  fused  chloride 
of  calcium,  free  from  powder, 
destined  to  retain  the  moisture. 
In  the  opposite  end  of  the  tube  d 
is  fixed,  air-tight,  another  tube,  e, 
made  of  glass  free  from  lead,  12 
inches  long,  and,  at  most,  V12  of 
an  inch  in  internal  diameter.  It 
must  be  observed  that  the  funnel 
tube  b  is  indispensably  necessary 
to  introduce  the  fluid  to  the  pieces 
of  perfectly  pure  metallic  zinc 
already  placed  in  the  bottle.  Hy- 
drogen gas  is  at  once  formed,  and 

if  arsenic  is  present,  in  even  the  smallest  quantity,  it  combines  with  the  hydrogen,  and 
{gaseous  arseniurettcd  hydrogen)  escapes.  If  the  gas  as  it  issues  from  the  jet  is  set  on  fire, 
no  product  but  water  is  generated  if  the  hydrogen  is  pure  ;  and  by  holding  against  the 
flame  a  cold  white  porcelain  basin,  or  piece  of  glass,  or  of  mica,  no  steam  is  produced,  and 
a  dew  is  formed  upon  the  cold  surface.  If  arsenic  be  present,  a  deposit  is  obtained,  which, 
according  to  the  part  of  the  flame  in  which  the  substance  to  receive  it  is  placed,  will  be 
either  a  brown  stain  of  metallic  arsenic,  or  a  white  one  of  arsenious  acid.  If  the  quantity 
of  arsenic  is  too  small  to  be  detected  in  this  way,  it  will  be  well  to  ignite  the  horizontal  part 
of  the  tube.  All  the  arseniuretted  hydrogen  will,  in  passing  that  point,  become  decom- 
posed, and  deposit  its  arsenic.  The  heat  will  drive  this  forward,  and  a  little  beyond  the 
heated  portion  metallic  arsenic  will  be  condensed.  Several  precautions  are  necessary  to  be 
observed ;  but  for  the  details  of  those  we  must  refer  to  works  especially  directed  to  the 
consideration  of  this  subject.  One  source  of  error  must,  however,  be  alluded  to.  A  com- 
pound of  antimony  and  hydrogen  is  formed  under  similar  circumstances ;  and  this  gas  in 
many  respects  resembles  the  compound  of  arsenic  and  hydrogen.  If  the  stain  formed  by 
the  flame  is  arsenic,  it  will  dissolve,  when  heated,  in  a  drop  or  two  of  sulpho-hydride  of 
ammonia,  and  a  lemon-j'ellow  spot  is  left ;  if  antimony  is  present,  it  leaves  a  yellow  stain. 
—  Wohler. 

7.  FleitmanrCs  Test. — If  a  solution  containing  arsenic  be  mixed  with  a  large  excess  of 
concentrated  solution  of  potassa,  and  boiled  with  fragments  of  granulated  zinc,  arseniu- 
retted hydrogen  is  evolved,  and  may  be  easily  reorganized  by  allowing  it  to  pass  on  to  a 
piece  of  filter  paper  spotted  over  with  solution  of  nitrate  of  silver.  These  spots  assume  a 
purplish-black  color,  even  when  a  small  quantity  of  arsenic  is  present.  This  experiment 
may  be  performed  in  a  small  flask,  furnished  with  a  perforated  cork  carrying  a  piece  of 
glass  tube  of  about  J  inch  diameter.  It  will  be  observed  that  this  test  serves  to  distinguish 
arsenic  from  antimony. 

The  following  remarks  on  the  Toxicological  Discovery  of  Arsenic  deserve  attention  : — 

This  active  and  easily  administered  poison  is  fortunately  one  of  those  most  easily  and 
certainly  discovered  ;  but  the  processes  require  great  precaution  to  prevent  mistaken  infer- 
ences :  if  due  care  is  taken,  arsenic  can  be  found  after  any  lapse  of  time,  as  well  as  after 
the  most  complete  putrefaction  of  the  animal  remains.  The  longest  time  after  which  it  has 
been  discovered  by  myself  is  eight  years,  which  was  the  case  of  an  infant ;  nothing  but  the 
bones  of  the  skeleton  remained,  the  coffin  was  full  of  earth,  and  large  roots  of  a  tree  had 
grown  through  it.  The  metal  was  obtained  from  the  bones,  and  in  the  earth  immediately 
below  where  the  stomach  had  existed.  Many  cases  have  occurred  in  my  experience,  wliere 
one,  two,  three,  four,  and  five  years  have  elapsed ;  in  one  case  after  fourteen  months,  where 
the  body  of  a  boy  had  been  floating  in  a  coffin  full  of  water.  The  poison  is  given  in  one 
of  three  states,  white  arsenious  acid,  yellow  sulphuret  ("orpiment")  or  "realgar,"  red 
sulphuret  of  arsenic ;  and  it  is  worthy  of  notice,  that  putrefaction  will  turn  cither  white  or 
red  into  yellow,  but  will  never  turn  yellow  into  either  white  or  red ;  this  is  owing  to  the 
hydrosulphuret  of  ammonia  disengaged  during  decomposition. 

Modern  toxicologists  have  abandoned  all  the  old  processes  for  the  detection  of  this  poi- 
son, and  have  adopted  one  of  two,  which  have  been  found  more  expeditious,  as  well  as 
more  certain.  The  first  was  proposed  by  Marsh,  of  Woolwich :  it  is  founded  upon  the 
principle  that  nascent  hydrogen  will  absorb  and  carry  oil"  any  arsenic  which  may  be  pres- 
ent, as  arseniuretted  hydrogen  ;  but  as  I  prefer  the  principle  first  proposed  by  Reinsch,  and 


112  AKSENIOUS  ACID. 

have  always  acted  upon  it,  I  shall  confine  my  description  to  the  processes  founded  upon  it 
The  principle  is  this :  arsenic  mixed  or  combined  with  any  organic  matter  will,  if  boiled 
with  pure  hydrochloric  acid  and  metallic  copper,  be  deposited  upon  the  copper ;  but  as  tliis 
depositing  property  is  also  possessed  by  mercury,  antimony,  bismuth,  lead,  and  tellurium, 
subsequent  operations  are  required  to  discriminate  between  the  deposits.  I  take  pieces  of 
copper  wire,  about  No.  13  size,  and  2^  inches  long;  these  I  hammer  on  a  polished  plane 
with  a  polished  hammer,  for  half  their  length,  {Jig.  41,)  and  having  brought  the  suspected 

matters  to  a  state  of  dryness,  and  boiled 
the  copper  blade  in  the  pure  hydrochloric 
acid,  to  prove  that  it  contains  no  metal  ca- 
pable of  depositing,  I  introduce  a  portion 
of  the  suspected  matter  and  continue  the  boiling ;  if  the  copper  becomes  now  either  steel- 
gray,  blue,  or  black,  I  remove  it,  and  wash  it  free  of  grease  in  another  vessel  in  which 
there  is  hot  diluted  hydrochloric  acid  ;  I  now  dry  it,  and,  with  a  scraper  with  a  fine  edge, 
take  off  the  deposit  with  some  of  the  adhering  copper,  and  repeat  the  boiling,  washing,  and 
scraping,  so  as  to  have  four  or  five  specimens  on  copper  ;  one  of  these  is  sealed  up  her- 
metically in  a  tube  for  future  production.  I  now  take  a  piece  of  glass  tube,  and  having 
heated  it  in  the  middle,  draw  it  out,  as  in  fg.  42,  dividing  it  at 
A,  each  section  being  about  2  inches  long,  the  wide  orifices  being 
about  '/lo  of  an  inch  in  diameter,  and  ^  an  inch  long,  the  capil- 
lary part  Ve  of  an  inch  in  diameter,  and  1^  inch  long ;  now,  by 
putting  one  portion  of  the  scrapings  into  one  of  the  tubes  at  b, 
and  holding  it  upwards  over  a  very  small  flame,  so  that  the  vola- 
tile products  may  slowly  ascend  into  the  narrow  portion  of  the  tube,  we  prove  the  nature 
of  the  deposit :  if  mercury,  it  condenses  in  minute  white  shining  globules  ;  if  lead  or  bis- 
muth, it  does  not  rise,  but  melts  into  a  yellowish  glass,  which  adheres  to  the  copper ;  if 
tellurium,  it  would  fall  as  a  white  amorphous  powder ;  if  antimony,  it  would  not  rise  at 
that  low  temperature ;  but  arsenious  acid  condenses  as  minute  octahedral  crystals,  looking 
with  the  microscope  like  very  transparent  grains  of  sand.  I  make  three  such  sublimates, 
one  of  which  is  sealed  up  like  the  arsenic  for  future  production.  I  now  cut  the  capillary 
part  of  another  of  the  tubes  in  pieces,  and  boil  it  in  a  few  diops  (say  10)  of  distilled  water, 
and  when  cold  drop  three  or  four  drops  on  a  plate  of  white  porcelain,  and  with  a  glass  rod 
drop  one  drop  of  ammoniacal  sulphate  of  copper  in  it :  and  now  to  make  the  colors  from 
this  and  the  next  test  more  conspicuous,  I  keep  a  chalk  stone,  planed  and  cleaned,  in  readi- 
ness, and  placing  on  it  a  bit  of  clean  white  filtering  paper,  I  conduct  the  drops  of  copper 
test  upon  the  paper,  which  permits  the  excess  of  copper  solution  to  pass  through  into  the 
chalk,  but  retains  the  smallest  proportion  of  Scheele's  green ;  tho  other  few  drops  of  the 
solution  are  treated  the  same  way  with  the  ammoniacal  nitrate  of  silver.  When  I  get  the 
yellow  precipitate  of  arsenite  of  silver,  the  papers,  with  these  two  spots,  are  now  dried  and 
sealed  up  in  a  tube  as  before,  and  that  with  the  silver  must  be  kept  in  the  dark,  or  it  will 
become  black.  I  have  still  one  of  the  tubes  with  the  arsenical  sublimate  remaining ; 
through  this  I  direct  a  stream  of  hydrosulphuric  acid  gas  for  a  few  seconds,  which  converts 
the  sublimate  into  yellow  orpiment.  I  have  now  all  five  tests :  the  metal,  the  acid,  arsenite 
of  copper,  arsenite  of  silver,  and  )-ellow  sulphuret ;  and  the  Viooooo  of  a  grain  of  arsenic  is 
sufficient  in  adroit  hands  to  produce  the  whole  ;  but  all  five  must  be  present,  or  there  is  no 
positive  proof,  for  many  matters  will  cause  a  darkness  of  flie  copper  in  the  absence  of 
arsenic, — sulphurets  even  from  putrefaction  ; — but  there  is  no  sublimate  in  the  second 
operation,  because  the  sulphur  burns  into  sulphurous  acid  and  passes  off  upwards.  Corn, 
grasses,  and  earth  slightly  darken  it  from  some  unknown  cause,  but  produce  no  sublimate ; 
so,  if  the  solution  of  suspected  arsenious  acid  is  tested  with  the  copper  test  while  hot,  it 
will  produce  a  greenish  deposit  of  oxide  of  copper,  through  the  heat  dissipating  a  little 
ammonia,  or  if  the  copper  blade  has  not  been  deprived  of  grease  by  the  diluted  hydro- 
chloric acid,  the  sublimed  acid  from  the  grease  will  precipitate  copper  from  that  test ;  but 
as  much  of  the  sulphuric  acid  of  commerce,  and  nearly  all  such  hydrochloric  acid  and  some 
commercial  zinc  contain  arsenic,  nothing  can  excuse  a  toxicologist  who  attempts  to  try  for 
arsenic  if  he  has  not  previously  experimented  with  all  his  reagents  ])cfore  he  introduces  the 
suspected  matters.  I  should  also  mention  that  this  metal  is  to  be  found  in  all  parts  of  the 
body,  but  longest,  and  in  greatest  quantity,  in  the  liver,  where  it  is  frequently  found  many 
days  after  it  has  disappeared  from  the  intestines. —  W.  Herapath. 

Arsenious  acid  of  commerce  is  frequently  adulterated  with  chalk  or  plaster  of  Paris. 
These  impurities  are  very  easily  detected,  and  their  proportions  estimated.  Arsenious  acid 
is  entirely  volatilized  by  heat,  con.sequently  it  is  sufficient  to  expose  a  weighed  quantity  of 
the  substance  to  a  temperature  of  about  400°  F.  in  a  capsule  or  crucible.  The  whole  of 
the  arsenic  will  pass  off  in  fumes,  while  the  impurities  will  be  left  behind  as  a  fixed 
residuum,  which  can,  upon  cooling,  be  weighed. 

It  is  scarcely  necessary  to  state  that,  the  fumes  of  arsenic  being  very  poisonous,  the 
volatilization  should  be  carried  on  under  a  chimney  having  a  good  draught. 


ARTESIAN"  WELLS.  113 

Our  Imports  of  Arsenic  were  as  follows : — 

1855 '73  cwts. 

1856 163     " 

ARTESIAN  WELLS.  The  most  remarkable  example  of  an  Artesian  well  is  that  at 
the  abattoir  of  Grenelle,  a  suburb  of  the  southwest  of  Paris,  where  there  was  a  great  want 
of  water.  It  cost  eight  years  of  ditKcult  labor  to  perforate.  The  geological  strata  round 
the  French  capital  are  all  of  the  tertiary  class,  and  constitute  a  basin  similar,  in  most  re- 
spects, to  that  upon  which  London  stands.  The  surface  at  Grenelle  consists  of  gravel, 
pebbles,  and  fragments  of  rocks,  which  have  been  deposited  by  the  waters  at  some  period 
anterior  to  any  historical  record.  Below  this  layer  of  detritus,  it  was  known  to  the  engi- 
neer that  marl  and  clay  would  be  found.  Underneath  the  marl  and  the  clay,  the  boring 
rods  had  to  perforate  pure  gravel,  plastic  clay,  and  finally  chalk.  No  calculation  from  geo- 
logical data  could  determine  the  thickness  of  this  stratum  of  chalk,  which,  from  its  powers 
of  resistance,  m^ht  present  an  almost  insuperable  olistaclo.  The  experience  acquired  in 
boring  the  wells  of  Elbeuf,  Rouen,  and  Tours,  was  in  this  respect  but  a  very  imperfect 
guide.  But,  supposing  this  obstacle  to  be  overcome,  was  the  engineer  sure  of  finding  a 
supply  of  water  below  this  mass  of  chalk  ?  In  the  first  place,  the  strata  below  the  chalk 
possessed  all  the  necessary  conditions  for  producing  Artesian  springs,  namely,  successive 
layers  of  clay  and  gravel,  or  of  pervious  and  impervious  beds.  M.  Mulot,  however,  relied 
on  his  former  experience  of  the  borings  of  the  wells  at  Rouen,  Elbeuf,  and  Tours,  where 
abundant  supplies  of  water  had  been  found  below  the  chalk,  between  similar  strata  of  clay 
and  gravel,  and  he  was  not  disappointed. 

The  strata  traversed  in  forming  this  celebrated  well  were  as  follows : — 

Drift-sand  and  gravel, 33  feet. 

Lower  tertiary  strata,       -         -         -         -         -         -         -         .  115" 

Chalk  with  flints, 1,148  \  ,  „„  .     ^^ 

Ditto,  lower, 246  f  ^'^^* 

Calcareous  sandstone,  clays,  and  sands  ending  in  a  bed  of  green- 
colored  sand, 256    " 

1,798     " 

The  surface  of  the  ground  at  the  well  is  102  feet  above  the  level  of  the  sea,  and  the 
water  is  capable  of  being  carried  above  this  to  a  height  of  120  feet. 

The  French  geologists  consider  that  the  sands  from  which  the  supply  is  obtained  are 
either  subordinate  beds  of  the  gault,  or  as  belonging  to  the  loiver  greensand.  They  crop 
out  in  a  zone  of  country  about  100  miles  eastward  of  Paris,  and  range  along  the  segment 
of  a  circle,  of  which  Paris  is  the  centre,  from  between  Sancerre  and  Auxerre,  passing  near 
to  Troyes,  thence  by  St.  Dizier  to  St.  Menehould.  The  outcrop  of  this  formation  is  con- 
tinued some  distance  further  north  ;  it  is  also  prolonged  beyond  Sancerre,  southwestward 
towards  Bourges,  Chatellerault,  and  then  northwest  to  Saumur,  Le  Mans,  and  Alenfon.  But 
the  superficial  area  which  it  occupies  in  these  latter  districts  does  not  appear  to  contribute 
to  the  water  supply  of  Paris,  for  the  axis  of  elevation  of  Mellerault  must  intercept  the  sub- 
terranean passage  of  the  water  from  the  district  south  of  that  line,  whilst,  on  the  north  of 
Paris,  the  anticlinal  line  of  the  "  Pays  de  Bray,"  and  some  smaller  faults  in  the  Aisne,  pro- 
duce probably  a  similar  stoppage  with  respect  to  the  northern  districts.  The  superficial 
area,  therefore,  from  which  the  strata  at  the  well  of  Grenelle  draw  their  supplies  of  water, 
forms  on  the  east  of  Paris  a  belt  stretching  from  near  Auxerre  to  St.  Menehould. 

The  exposed  surface  of  the  water-bearing  beds  which  supply  the  well  of  Grenelle  is 
about  117  square  miles;  the  subterranean  area  in  connection  with  these  lines  of  outcrop 
may  possibly  be  about  20,000  square  miles,  and  the  average  thickness  of  the  sands  of  the 
gres  verts,  serving  in  their  underground  range  as  a  reservoir  for  the  water,  does  not  proba- 
bly exceed  30  or  40  feet. — Prestwu-h  on  the  Water-bearing  Strata  of  London. 

As  the  cost  of  these  wells  is  an  important  consideration,  the  following  statement  from 
the  "  Water-bearing  Strata  of  London  "  is  of  much  value  : — 

"  M.  Degoussee  has  recently  informed  me  of  his  having  contracted  to  bore  an  Artesian 
well  at  Rouen  to  the  depth  of  1,080  feet,  (through  the  lower  cretaceous  and  oolitic  series,) 
for  £1,600,  expenses  of  every  kind  to  be  defrayed  by  him.  M.  Degoussee  has  constructed 
three  Artesian  wells  in  different  parts  of  France,  of  about  820  to  830  feet  each,  at  an  ex- 
pense, including  tubes  and  all  expenses,  of  from  £600  to  £1,000.  The  Calais  well  offer.s 
a  very  near  counterpart  of  the  deposits  which  occur  beneath  London,  but  the  difficulties  of 
the  first  240  feet  much  exceeded  those  which  would  be  met  with  here,  and  the  chalk  is 
probably  100  to  200  feet  thicker.  Here  and  at  Paris  the  first  1,000  feet  cost  less  than 
£3,000,  and  at  Donchcrry  apparently  not  much  more  tlian  £2,000." 

The  following  Table  shows  the  cost  of  several  of  the  Artesian  wells  of  France : — 
Vol.  III.— 8 


114  ARTILLERY. 

Crenelle,         Dept.  Seine,        -        -         1,'798  feet       -         -         -     £14,500 
Calais,  "      Pas  de  Calais,    -         1,138    "...         3^500 

Donchery,  "      Ardennes,  -         1,215    "...         3,045 

St.  Fargeau,        "      Yonne,      -         -  GG6    "         -         -         -         1,21G 

Lille,  "      Nord,        -         -  592    "         -         -         -  320 

Crosne,  "      Seine  and  Oise,  333    "         -         -         -  190 

Brou,  "      Marne,      -         -  246    "         -         -         -  200 

Ardres,  "      Nord,        -        -  155    "         -         -        -  64 

Claye,  "      Seine  and  Marne,  108    "...  78 

Chavllle,  "      Oise,         -         -  65    "         -         .         -  15 

It  appears  that,  in  England,  the  cost  of  boring  is  about  5s.  for  the  first  10  feet,  £2  10s. 
for  forty  feet,  £5  5s.  for  60  feet,  £13  15s.  for  100  feet,  and  so  on  in  proportion.  (See  Sir 
Charles  Lyell's  "  Principles  of  Geology,"  where  the  geological  question  is  fully  treated.) 

ARTILLERY.  One  of  the  first  inquiries  of  importance  in  connectioji  with  the  con- 
struction of  pieces  of  artillery  is  that  of  the  liability  to  fracture  in  the  metal.  Upon  this 
point  the  researches  of  Mr.  Mallet  furnish  much  important  matter.  He  tells  us,  as  the 
result  of  his  investigation,  that  it  is  a  law  of  the  molecular  aggregation  of  crystalline 
solids,  that  when  their  particles  consolidate  tinder  the  infiience  of  heat  in  rnotioji,  their 
crystals  arrange  and  group  themselves  with  their  principal  axes  in  lines  perpendicular  to 
the  cooling  or  heating  surfaces  of  the  solid :  that  is,  in  the  lines  of  the  direction  of  the 
heat-wave  in  motion,  which  is  the  direction  of  least  pressure  within  the  tnass.  And  this  is 
true,  whether  in  the  case  of  heat  passing  from  a  previously  fused  solid  in  the  act  of  cool- 
ing and  crystallizing  in  consolidation,  or  of  a  solid  not  having  a  crystalline  structure,  but 
capable  of  assuming  one  upon  its  temperature  being  sufficiently  raised,  by  heat  applied  to 
its  external  surfaces,  and  so  piassing  into  it. 

Cast-iron  is  one  of  those  crystallizing  bodies  which,  in  consolidating,  obeys,  more  or 
less  perfectly  according  to  conditions,  the  above  law.  In  castings  of  iron  the  planes  of 
crystallization  group  themselves  perpendicularly  to  the  surfaces  of  external  contour.  Mr. 
Mallet,  after  examining  the  experiments  of  Mr.  Fairbairn — who  states  ("  Trans.  Brit.  Ass.," 
1853)  that  the  grain  of  the  metal  and  the  physical  qualities  of  the  casting  improve  by  some 
function  of  the  number  of  meltings ;  and  he  fixes  on  the  thirteenth  melting  as  that  of 
greatest  strength — shows  that  the  size  of  crj'stals,  or  coarseness  of  grain  in  castings  of  iron, 
depends,  for  any  given  "  make  "  of  iron  and  given  mass  of  casting,  upon  the  high  tempera- 
ture of  the  fluid  iron  above  that  just  necessary  to  its  fusion,  which  influences  the  time  that 
the  molten  mass  takes  to  cool  down  and  assjime  the  solid  state. 

The  very  lowest  temperature  at  which  iron  remains  liquid  enough  fully  to  fill  every  cav- 
ity of  the  mould  without  risk  of  defect  is  that  at  which  a  large  casting,  such  as  a  heavy  gun, 
ought  to  be  "  poured."  Since  the  cooling  of  any  mass  depends  upon  the  thickness  of  the 
casting,  it  is  important  that  sudden  changes  of  form  or  of  dimensions  in  the  parts  of  cast- 
iron  guns  should  be  avoided.  In  the  sea  and  land  service  13-inch  mortars,  where,  at  the 
chamber,  the  thickness  of  metal  suddenly  approaches  twice  that  of  the  chase,  is  a  malcon- 
struction  full  of  evils. 

The  following  statements  of  experiments  made  to  determine  the  effect  produced  on  the 
quality  of  the  iron  in  guns,  by  slow  or  rapid  cooling  of  the  casting,  are  from  the  report  of 
Major  W.  "Wade,  of  the  South  Boston  Foundry,  to  Colonel  George  Bomford,  of  the  Ord- 
nance Department  of  the  United  States.  Three  six-pounder  cannon  were  cast  at  the  same 
time  from  tlie  same  melting  of  iron.  The  moulds  were  similar,  and  prepared  in  the  usual 
manner.  That  in  which  No.  1  was  cast  was  heated  before  casting,  and  kept  heated  after- 
wards by  a  fire  which  surrounded  it,  so  that  the  flask  and  mould  were  nearly  red-hot  at  the 
time  of  casting  ;  and  it  was  kept  up  for  three  days.  Nos.  2  and  3  were  cast  and  cooled  in 
the  usual  way. 

At  the  end  of  the  fourth  day,  the  gun  No.  1  and  flask  were  withdrawn  from  the  heating 
cylinder  while  all  parts  were  yet  hot.  Nos.  1  and  2  were  bored  lor  6-pounders  in  the  usual 
way  ;  No.  3  for  a  12-poundcr  howitzer,  with  a  6-pounder  chamber.  The  firing  of  the  guns 
was  in  every  respect  the  same.  Nos.  1  and  2  were  fired  the  same  number  of  times  with 
similar  charges.  No.  1  burst  at  the  2'7th  fire,  and  No.  2  at  the  25th.  It  appears,  from 
tlicse  results,  that  no  material  effect  is  produced  on  the  quality  of  the  iron  by  these  differ- 
ent modes  of  cooling  the  castings. 

A  very  extensive  series  of  experiments  were  made  by  the  order  of  the  United  States 
Government,  on  the  strength  of  guns  cast  solid  or  hollow.  In  these  it  was  confirmed  that 
the  gims  cast  hollow  endured  a  much  more  severe  strain  than  those  cast  solid.  Consider- 
able differences  were  also  observed,  whether  the  casting  was  cooled  from  within  or  without; 
and  Lieutenant  Rodman's  method  of  cooling  from  the  interior  is  regarded  as  tending  to 
prevent  injurious  strains  in  cooling. 

5Injor  Wade  informs  us  that  time  and  repose  have  a  surprising  effect  in  removing  strains 
caused  by  the  unequal  coolings  of  iron  castings. 

Great  improvements  have  been  made  in  improving  the  quality  of  iron  guns.     Guns  cast 


ARTILLERY. 


115 


prior  to  1841  had  a  density  of  7*148,  with  a  tenacity  of  23,638.     Guns  cast  in  1851  had  a 
density  of  7-289,  with  a  tenacity  of  37,774. 

The  following  Table  gives  the  results  of  all  the  trials  made  for  the  United  States  .Gov- 
ernment, showing  the  various  qualities  of  different  metals : — 


Torsion. 

Com- 

Metals. 

Density. 

Tenacity. 

Strength. 

At  Half 
Degree. 

Ultimate. 

pressive 
Strength. 

Hardness. 

Cast-iron : — 

Least    - 

6-900 

9,000 

5,000 

3,861 

5,605 

84,592 

4-57 

Greatest 

7-400 

45,970 

11,500 

7,812 

10,467 

174,120 

33-51 

Wrought  iron : — 

Least    - 

7-704 

38,027 

6,500 

3,197 

- 

40,000 

10-45 

Greatest 

7-858 

74,592 

- 

4,298 

7,700 

127,720 

1214 

Bronze : — 

Least    - 

7-978 

17,698 

- 

2,021 

5,511 

- 

4-57 

Greatest 

8-953 

56,786 

- 

- 

- 

. 

5-94 

Cast-steel: — 

Least    - 

7-729 

- 

- 

- 

- 

198,944 

Greatest 

7-862 

128,000 

23,000 

- 

- 

391,985 

The  following  analyses  of  the  metal  of  iron  guns  of  three  qualities  are  important. 
Influence  of  Single  Ingredients. 


Classes. 

Mechanical  Tests. 

Chemical  Constituents. 

Specific 
Gravity. 

Tensile 
Strength. 

Combined 
Carbon. 

Graphite. 

Silicium. 

'"^o-     phorus. 

Sulphur. 

Earthy 
Metals. 

1 
2 
3    . 

7-204 
7-140 

7-088 

28,865 
24,767 
20,176 

•0977 
-0819 
•0726 

•0507 
•0576 
•0560 

•0417 
•0538 
•0531 

•0215 
•0200 
•0219 

.0239 
•0300 
•0321 

•0017 
•0021 
•0021 

•0117 
•0094 
•0144 

Influence  of  two  or  more  Ingredients. 


Classes. 

Mechanical  Tests. 

Chemical  Constituents. 

Specific 
Gravity. 

Tensile 
Strength. 

Silicium 

and 
Carbon. 

Silicium 
and  Slag. 

Graphite 
and  Slag. 

Graphite, 
Silicium, 
and  Slag. 

Graphite, 
Slag,  Sili- 
cium, and 
Phosphorus. 

Total 
Carbon. 

1 
2 
3 

7-204 
7-140 
7  •OS  8 

28,865 
24,767 
20,176 

•1394 
•1357 
•1257 

•0632 
•0738 
-0750 

•0722 

•0776 
80 

•1139 
•1314 
-1311 

•1378 
•1614 
•1632 

•1484 
-1395 
•1286 

An  inspection  of  the  first  of  the  foregoing  tables,  representing  the  average  amount  of 
each  foreign  ingredient  in  gun-metal  deduced  from  all  the  analyses,  shows  a  considerable 
difference  in  the  proportions  of  those  ingredients  in  each  of  the  three  classes  into  which 
guns  are  divided.  It  will  be  observed,  that  while  the  proportion  of  combined  carbon 
diminishes  from  the  1st  to  the  3d  class,  that  of  silicium  similarly  increases,  so  that  their 
united  amounts  are  nearly  the  same.  In  other  words,  it  appears  that  silicium  can  replace 
the  carbon  to  a  certain  extent ;  but  that  the  quality  of  the  metal  is  injured  where  the 
amount  of  the  silicium  approaches  that  of  the  carbon.  Karstcn  made  a  siuiilar  observation 
in  determining  the  limits  between  cast-iron  and  steel,  but  did  not  notice  the  influence  of 
that  substitution. 

But  the  differences  become  more  striking  by  combining  the  ingredients  variously  to- 
gether, as  in  the  second  of  those  tables ;  and  especially  by  comparing  the  extremes,  which 
are  each  derived  from  a  larger  number  of  observations  than  the  mean. 

After  showing  the  total  amount  of  carbon,  (both  combined  and  uncombined,)  silicium 
and- combined  carbon  are  thrown  together,  which  indicates  the  replacement  by  silicium  of 
that  portion  of  carbon  set  free  in  the  form  of  graphite.  The  column  "  siliciuin  and  slag  " 
shows  the  general  depreciation  of  the  metal  as  the  silicious  metal  increases. — From  the 
Report  of  Campbell  Morfit  and  James  G.  Booth  to  the  Ordnance  Office,  United  States 
Army, 


116 


ARTILLERY. 


The  following  analyses,  (rejecting  those  substances  of  which  only  a  mere  trace  has  been 
discovered,)  from  the  same  chemists,  are  selected  as  showing  striking  peculiarities  : — 


5  o 

s" 

i 

S 

s 
'3 

a    1    -H 

li 

Class. 

g 

^1 

1 

ti 

M 

a 

1 

alciu 

u 

- 

o 

Ui 

U3 

" 

" 

o      !     -<; 

to  * 

1.  32-pdr.,which  endured 

the  extreme  proof 

•93520 

■02000 

■02200 

■00776 

■00250 

•00036 

■02100 

- 

■00028  -ooioe 

2.  32-pdr.,which  endured 

•  the  extreme  proof. 

t 

Hot  blast  iron    - 

■SS480 

•02S00 

•00200 

■02000 

•00400 

•00666 

•05212 

•00072 

■00043    -     - 

■00034 

24-pdr.,which  endured 

the  extreme  proof 

Hot  blast  iron    - 

92400 

•03000 

■01200 

■01790 

■00200  •00626 

■02244 

•00080 

•00028  ^00234 

3.  42-pounder 

92155 

•03200 

■oyiou 

■1)1130 

■00100  ■oosoo 

■0144S 

■00074 

■00086  ■00316 

■00220 

32-pounder 

92540 

•02800 

■00 150 

■007oO 

■01)200  -00738 

■02317 

■00061 

•00057  ^00170 

32-pounder     - 

93450 

•02900 

■00900 

■00900 

■00200  ^-01290 

■01810 

' 

?     ■ooiss 

■00026 

Comparison  of  Wei[;hf,  Strength,  Extensibility^  and  Stiffness  ;   Cast-iron  being  unity 
witlmi  practical  limits  to  static  forces  only. 


Material. 

Weight  for 
=  Volume. 

Strength. 

Extensibility. 

Stiffness. 

Torsion. 

Cast-iron    - 
Gun-metal 
Wrought  iron     - 
Steel 

1-00 
1-18 
1-07 
1-07 

1-00 
0-65 
3-00 
4^75 

1  00 
1-27 
0-45 
0-32 

1-00 
0-53 
2^20 
3-15 

1-00 
0-55 
Ml 
2-11 

We  find  that  wrought-iron  guns  are  more  than  five-fold  as  durable  as  those  of  gun- 
metal,  and  twenty-two  times  as  durable  as  those  of  cast-iron.  And  taking  first  cost  and 
durability  together,  gun-metal  canfion  are  about  seventy-seven  times,  and  cast-iron  guns 
about  thirty  times,  as  dear  as  wrought-iron  artillery.  Again :  the  cost  of  horse-labor,  or 
other  means  of  transport  for  equal  strength,  (and,  of  course,  therefore,  for  equal  effective 
artillery  power,)  is  about  five  times  as  great  for  gun-metal,  and  nearly  three  times  as  great 
for  cast-iron  as  for  wrought-iron  guns.  In  every  respect  in  which  we  have  submitted  them 
to  a  comparison,  searching  and  rigid,  and  that  seems  to  have  omitted  no  important  point  of 
inquiry,  wrought  iron  stands  pre-eminently  superior  to  every  other  material  for  the  fabrica- 
tion of  ordnance. —  United  States  Eeport. 

The  advantages  possessed  by  rolled  bars  for  the  construction  of  artillery  are  thus 
summed  up  by  Mr.  Mallet,  in  his  "  Memoir  on  Artillery  "  : — 

1.  The  iron  constituting  the  integrant  parts  is  all  in  moderate-sized,  straight,  prismatic 
pieces,  formed  of  rolled  bars  only  ;  hence,  with  its  fibre  all  longitudinal,  perfectly  uniform, 
and  its  extensibility  the  greatest  possible,  and  in  the  same  direction  in  which  it  is  to  be 
strained — it  is,  therefore,  a  better  material  than  any  forged  iron  can,  by  possibility,  be 
made. 

2.  The  limitation  of  manufacture  of  the  fron,  thus,  to  rolling,  and  the  dispensing  with 
all  massive  forgings,  insure  absolute  soundness  and  uniformity  of  properties  in  the 
material. 

3.  The  limited  size  of  each  integrant  part,  and  the  mode  of  preparation  and  combina- 
tion, afford  unavoidable  tests  of  soundness  and  of  perfect  workmanship,  step  by  step,  for 
every  portion  of  the  whole  :  unknown  or  wilfully  concealed  defects  are  impossible. 

4.  Facility  of  execution  by  ordinary  tools,  and  under  easily  obtained  conditions,  and 
without  the  necessity  of  cither  for  peculiarly  skilled  labor  on  the  part  of  "  heavy  forge- 
men,"  or  for  steam  and  other  hammers,  &c.,  of  unusual  power,  and  very  doubtful  utility  ; 
and  hence  very  considerable  reduction  in  cost  as  compared  with  wrought-iron  artillery 
forged  in  mass. 

5.  Facility  of  transport  by  reduction  of  weight,  as  compared  with  solid  guns  of  the 
same  or  of  aivy  other  known  material. 

6.  A-bcttcr  material  than  massive  forged  iron,  rolled  bars  are  much  more  scientifically 
and  advantageously  applied  ;  the  same  section  of  iron  doing  much  more  resisting  work,  as 
applied  in  the  gun  built-up  in  compressed  and  extended  plies,  than  in  any  solid  gun. 

7.  The  introduction  thus  into  cannon  of  a  principle  of  elasticity,  or  rather  of  elastic 
range,  (as  in  a  carriage-spring  divided  into  a  number  of  superimposed  leaves,)  greater  than 
that  due  to  the  modulus  of  elasticity  of  the  material  itself;  and  so  acting,  by  distribution 
of  tlie  maximum  effort  of  the  explosion,  upon  the  rings  successively  recipient  of  the  strain 
during  the  time  of  the  ball's  traject  through  the  chase,  as  materially  to  relieve  its  effects 
upon  the  gun. 


AKTILLERY. 


117 


Considerable  attention  has  been  given,  of  late  years,  to  the  construction  of  very  power- 
ful pieces  of  ordnance.  Cast-iron  cannon  are  usually  employed,  but  these  very  soon  be- 
come useless  when  exposed  to  the  sudden  shocks  of  rapid  firing.  Cast-iron  is,  compara- 
tively speaking,  a  weak  substance  for  resisting  extension,  or  for  withstanding  the  explosive 
energy  of  gunpowder,  compared  with  that  of  wrought-iron,  the  proportion  being  as  1  is  to  5  ; 
consequently,  many  attempts  have  been  made  to  substitute  wrought-iron  cannon  for  cast. 

A  gun,  exhibited  in  1851  by  the  Belgian  Government,  made  of  cast-iron  '■^prepared 
with  coke  and  wood"  was  said  to  have  stood  2,116  rounds,  and  another,  3,647  rounds,  with- 
out much  injury  to  the  touch  hole  or  vent.  Another  is  said  to  havo^been  twice  "  rebouched," 
and  has  stood  6,002  rounds  without  injury.  As  few  guns  of  cast-iron  will  stand  more  than 
800  rounds  without  becoming  unserviceable,  this  mode  of  preparing  the  iron  appears  to  be 
a  great  improvement.  At  St.  Sebastian,  2,700  rounds  were  fired  from  the  English  bat- 
teries, but,  as  was  observed  by  an  eye-witness,  "  you  could  put  your  fist  into  the  touch- 
holes." — Colonel  James^  R.  E. 

In  Prussia  they  have  for  some  time  made  cannon  of  "  forged  cast-steel."  To  get  over 
the  difficulty  of  forging  the  gun  with  the  trunnions  on,  the  gun  has  been  made  without 
them,  and  a  hollow  casting  with  trunnions  afterwards  slipped  over  the  breech,  and  secured 
in  its  proper  position  by  screening  in  the  cascable.  The  tenacity  of  this  metal  must  be 
very  great. 

Casting  of  Guns. — Guns  have  long  been  cast  in  a  vertical  position,  and  with  a  certain 
amount  of  "  head  of  metal "  above  the  topmost  part  of  the  gun  itself.  One  object  gained 
by  this  (of  great  value)  is  to  afford  a  gathering-place  for  all  scoria,  or  other  foreign  matter ; 
an  end  that  might  be  much  more  effectually  accomplished  were  the  metal  always  run  into 
the  cavity  of  the  mould  by  "  gaits  "  leading  to  the  bottom,  or  lowest  point,  in  place  of  the 
metal  being  thrown  in  at  the  top,  with  a  fall,  at  first,  of  several  feet,  as  is  now  the  common 
practice,  by  which  much  air  and  scoria  are  carried  down  and  mixed  with  the  metal,  some  of 
which  never  rises  up  again,  or  escapes  as  "  air-bubbles."  (See  "  Mallet  on  the  Physical 
Conditions  involved  in  the  Construction  of  Artillery." 

Table  showing  the  Increase  of  Density  in  Casti^igs  of  large  Size,  due  to  their  Solidification 
lender  a  Head  of  Metal,  varying  from  two  to  fourteen  Feet : — 


13 

s 

a 
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1^ 

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t2i 

Calder  Cast-iron,  No.  1. 
Hot  Blast. 

Blaenavon,  No.  1. 
Cold  Blast. 

Apedale,  No.  2. 
Hot  Blast. 

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The  experiments  were  made  upon  cylindrical  shafts  of  cast-iron,  cast  vertically  in  dry 
sand-mould,  under  heads  gradually  increasing  up  to  fourteen  feet  in  depth,  and  all  poured 
from  "  gaits  "  at  the  bottom. 

These  experiments  show  an  increase  of  density  due  to  fourteen  feet  head,  about  equal 
to  a  pressure  of  ^4-8  lbs.  per  square  inch  on  the  casting ;  from  0-9551  to  7-1035  for  Scotch 
cast-iron. 

In  the  foregoing  paper  frequent  reference  has  been  made  to  the  investigations  of  Mr. 
Mallet.  His  monster  mortar  promises  such  results  that  an  especial  account  of  it  appears  to 
be  required. 

About  the  latter  end  of  1854,  the  attention  of  Mr.  Robert  Mallet,  C.  E.,  was  directed  to 
the  mathematical  consideration  of  the  relative  powers  of  shells  in  proportion  to  tlicir  in- 
crease of  size  or  of  diameter.  His  inquiries  resulted  in  a  memoir  presented  by  him  to 
Government,  in  which  he  investigated  the  increase  of  power  in  .shells  with  increase  of  diam- 
eter, under  the  heads  of: — 1,  Their  penetrative  power;  2,  Their  increased  range  and 
greater  accuracy  of  fire  ;  3,  Their  explosive  power ;  4,  Their  power  of  demolition,  or  of 
levelling  earthworks,  buildings,  &c.  -,  5,  Their  fragmentary  missile  power ;  6,  and  lastly, 
their  moral  effect, — in  every  case  viewing  the  shell,  not  as  a  ^vCapon  against  troops,  but  as 


118  ARTILLERY. 

an  instrument  of  destruction  to  an  enemy's  works.  The  result  so  convinced  Mr.  Mallet  of 
the  rapid  rate  at  which  the  destructive  powers  of  a  shell  increase  with  increase  of  size,  that 
he  wa.s  induced  to  propose  to  Government  the  employment  of  shells  of  a  magnitude  never 
before  imagined  by  any  one,  namely,  of  a  yard  in  diameter,  and  weighing,  when  in  flight, 
about  a  ton  and  a  quarter  each  ;  and  to  prepare  designs,  in  several  re.«pects  novel  and  pecu- 
liar, for  the  construction  of  mortars  capable  of  projecting  these  enormous  globes.  Such  a 
mortar  was  made,  and  on  the  19th  of  October,  1857,  the  first  of  those  colossal  mortars  con- 
structed from  Mr.  Mallet's  design  was  fired  on  Woolwich  Marshes,  with  charges  (of  projec- 
tion) gradually  increasing  up  to  10  lbs.  ;  and  with  the  latter  charge  a  shell  weighing  2,550 
lbs.  was  thrown  a  horizontal  range  of  upwards  of  a  mile  and  a  half  to  a  height  of  probably 
three-quarters  of  a  mile,  and  falling,  penetrated  the  compact  and  then  hard  dry  earth  of  the 
Woolwich  range  to  a  depth  of  more  than  18  feet,  throwing  about  cart-loads  of  earth  and 
stones  by  the  mere  splash  of  the  fall  of  the  empty  shell.  What  would  have  been  the  crater 
blown  out,  if  the  bursting  charge  of  400  lbs.  of  powder  had  been  within  ! 

It  would  be  out  of  place  here  to  attempt  to  follow  Mr.  Mallet's  mathematical  results  as 
to  the  relative  powers  of  small  and  large  shells ;  some  popular  notion,  however,  of  the  sub- 
ject may  be  given  in  a  few  words. 

Say  we  have  a  13-inch  shell  and  a  36-inch  shell,  and,  for  simplicity,  that  each  has  the 
same  proportion  of  iron  and  powder  in  relation  to  their  bulks,  or  the  same  density.  Roughly, 
the  larf^c  shell  may  be  said  to  be  three  times  the  diameter  of  the  small  one.  Then,  a  ring 
or  circle  through  which  the  larger  one  will  just  pass  will  have  nine  times  the  area  of  that 
through  which  the  smaller  one  will  just  pass,  and  the  weight  of  the  large  shell  will  be  27 
times  that  of  the  small  one. 

If  the  two  shells,  then,  be  thrown  at  the  same  angle  of  elevation  and  at  the  same  ve- 
locity, the  larger  shell  will  range  greatly  further  than  the  small  one,  for  their  relative 
resistances  in  the  air  are  about  as  1  to  9,  while  their  relative  energy  of  motion  or  momen- 
tum is  as  1  to  27. 

A  13-inch  shell,  weighing  about  180  lbs.,  is  thrown,  by  a  charge  of  30  lbs.  of  powder, 
barely  4,700  yards.  While,  with  not  much  more  than  double  this  amount  of  powder,  the 
3G-inch  shell,  of  more  than  14  times  its  weight,  can  be  thrown  2,650  yards,  or  much  more 
than  half  the  distance. 

The  explosive  power,  it  is  obvious,  is  approximately  proportionate  to  the  weight  of  pow- 
der ;  but,  by  calculations,  of  which  the  result  only  can  here  be  given,  Mr.  Mallet  has  shown 
that  the  total  pow*r  of  demolition — that  is  to  say,  the  absolute  amount  of  damage  done  in 
throwing  down  buildings,  walls,  &c.,  &c. — by  one  36-inch  shell,  is  1,600  times  that  possible 
to  be  done  by  one  13-inch  shell ;  and  that  an  object  which  a  13-inch  shell  could  just  over- 
turn at  one  yard  from  its  centre,  will  be  overthrown  by  the  36-inch  shell  at  40  yards' 
distance. 

A  13-inch  shell  penetrates,  on  falling  upon  compact  earth,  about  2 J  feet.  The  Antwerp 
shell  penetrated  7  feet.  The  36-inch  shell  penetrated  16  to  18  feet.  The  funnel-shaped 
cavity,  or  "  crater,"  of  earth  blown  out  by  the  explosion  of  a  buried  shell,  is  always  a  simi- 
lar figure,  called  a  "  paraboloid  ;"  its  diameter  at  the  surface,  produced  by  the  13-inch  shell, 
is  about  7  feet,  and  by  the  36-inch  shell  about  40  feet. 

Shells. — The  hollow  explosive  projectiles  that  we  call  shells  or  bombs  are  a  very  old 
invention.  Under  the  name  of  "  coininges,"  they  consisted  of  rudely  formed  globes  of 
plate  iron  soldered  together,  filled  with  gunpowder  and  all  sorts  of  miscellaneous  "  mitraille." 
These  were  thrown  to  short  distances  both  from  "  picrriers "  (a  sort  of  mortar)  and  from 
catapultae,  as  early  as  1495  at  Naples,  1590  at  Padua,  1520  at  Heilsberg,  1522  at  Rhodes, 
and  1542  at  Boulogne,  Lieges.  About  the  middle  of  the  15th  century,  bombs  of  cast-iron 
seem  to  have  come  into  use ;  an  Englishman,  named  Malthus,  learned  the  art  of  throwing 
them  from  the  Dutch,  and  perfected  the  system  for  the  French  armies — being  the  first  to 
throw  shells  in  France,  at  the  siege  of  La  Mothe,  in  1643.  The  diameter  of  the  bomb 
secma  at  that  time  to  have  become  fixed  at  13  inclies — the  old  Paris  foot ;  and  at  this  it 
remains  (with  very  few  exceptional  cases)  down  to  the  present'day. 

A  few  attempts  to  increase  the  size  and  power  of  these  projectiles  have  been  made  at 
different  jicriods,  but  never  with  the  practical  skill  necessary  to  success;  for  example,  18- 
inch  shells  were  thrown  by  the  French,  at  the  siege  of  Tournay,  in  1745  ;  whereas,  just  a 
century  before,  the  Swedes  threw  shells  of  462  lbs.  weight,  and  holding  40  lbs.  of  powder. 
The  Froiich,  when  they  occupied  Algiers  in  1830,  found  nunilwrs  of  olU  shells  of  nearly  900 
lbs.  in  weight;  and  in  almost  every  arsenal  and  fortress  in  Europe  one  or  two  old  16-inch 
and  18-inch  shells  are  to  be  found.  No  attempt  was  made  in  modern  days  to  realize  the 
vast  accession  of  power  that  such  large  shells  confer,  until  the  year  1832,  when  the  "  mon- 
ster mortar,"  as  it  was  then  called,  of  24  inches'  calibre,  designed  by  Colonel  Paixhans,  (the 
author  of  the  Paixhans  gun,)  was  constructed  by  order  of  Baron  Evain,  the  Belgian  minis- 
ter of  war,  and  attempted  to  be  used  by  the  French  at  the  siege  of  the  citadel  at  Antwerp, 
but  with  the  worst  possible  success.  The  mortar,  a  crude  cylindrical  mass  of  cast-iron, 
sunk  in  a  bed  of  timber  weighing  about  8  tons,  and  provided  neither  with  adequate  means 


ARTILLERY. 


119 


for  "  laving"  it,  nor  for  charging  it — the  heavy  shells  weighing,  when  filled  with  99  lbs.  of 
powder j  1,015  lbs.  each — could  with  difficulty  be  fired  three  rounds  in  two  hours,  while  the 
shells  themselves  were  very  badly  proportioned. 

One  of  these  shells  fell  nearly  close  to  the  powder  magazine,  but  did  not  explode  ;  had 
it  fallen  upon  the  presumed  bomb-proof  arch  of  the  magazine,  containing  300,000  lbs.  of 
powder,  it  would  have  pierced  it,  according  to  the  opinion  of  all  the  military  engineers 
present' at  the  siege  ;  and  so  closed  the  enterprise  at  a  blow.  The  ill  success  of  this  mortar 
prevented  for  several  years  any  attempt  to  develop  bombs  into  their  legitimate  office — as 
the  means  of  suddenly  transferring  mines  into  the  body  of  fortified  places — of  a  power 
adequate  to  act  with  decisive  effect  upon  their  works  ;  although  some  years  afterwards  a  20- 
inch  mortar  was  made  in  England  for  the  Pacha  of  Egypt,  and  proved  at  Woolwich. 

But  another  circumstance  still  more  tended  to  the  neglect  of  large  shells  thrown  by  ver- 
tical fire.  After  repeated  trials  and  many  failures,  it  was  found  practicable  to  throw  10- 
inch  (and  since  that  even  13-inch)  sliells  from  cannon,  or  "  shell-guns,"  by  projecting  them 
nearly  horizontally,  or  at  such  low  angles  that  they  should  "  ricochet "  and  roll  along  the 
ground  before  they  burst ;  and,  thus  fired,  it  was  soon  seen  that  their  destructive  power  as 
against  troops  was  greater  than  if  fired  at  angles  approaching  45°  of  elevation  from  mor- 
tars. Paixhans  and  his  school  had  pushed  a  good  and  useful  invention  beyond  its  proper 
limits,  and  had  lost  sight  wholly  of  the  all-important  fact,  that  horizontal  shell-fire,  powerful 
as  it  is  against  troops  or  shipping,  is  all  but  useless  as  an  instrument  of  destruction  to  the 
works  (the  earthwork  and  masonry,  &c.)  of  fortified  places;  for  this  end,  weight  and  the 
penetrative  power  due  to  the  velocity  of  descent  in  falling  from  a  great  height  are  indis- 
pensable. 

No  bomb-proof  arch  (so  called)  now  exists  in  Europe  capable  of  resisting  the  tremen- 
dous fall  of  such  masses,  and  the  terrible  powers  of  their  explosion  when  480  lbs.  of  pow- 
der, fired  to  the  very  best  advantage,  put  in  motion  the  fragments  of  more  than  a  ton  of 
iron.  No  precautions  are  possible  in  a  fortress ;  no  splinter-proof,  no  ordinary  vaulting, 
perhaps  no  casemate,  exists  capable  of  resisting  their  fall  and  explosion.  Such  a  shell 
would  sink  the  largest  ship  or  floating  battery. 

A  single  36-inch  shell  in  flight  costs  £25,  and  a  single  13-inch  £2  2s.,  yet  the  former  is 
the  cheaper  projectile  ;  for,  according  to  Mr.  Mallet's  calculations,  to  transfer  to  the  point 
of  effect  the  same  weight  of  bursting  powder,  we  must  give — 


55  shells  of  13  inches,  at  £2  2s. 
Against  1  shell  of  36  inches    - 


£115  10  0 
25     0  0 


Showing  a  saving  in  favor  of  the  large  shell  of       -         -       £90  10  0 

And  this  assumes  that  55  small  shells,  or  any  number  of  them,  could  do  the  work  of  the 
single  great  one. 

We  must  briefly  notice  the  mortars  from  which  these  projectiles  are  proposed  to  be  shot, 
and  of  which  fg.  46  gives  an  elevation,  with  section  of  bore  and  chambers  and  lines  of 
separation  in  dotted  lines. 

46 


|j^lil/»;lil^lllfh^llllP.I^I^PI^I^Ill^l^l#lililir 


120 


ASBESTUS. 


These  mortars  are,  with  the  exception  of  one  part,  (the  base,)  and  the  elm  timber  ends, 
formed  wholly  of  wrought  iron,  in  concentric  rings,  and  each  entire  mortar  is  separable  at 
pleasure  into  thirteen  separate  pieces,  the  heaviest  of  which  weighs  about  11  tons,  so  that 
the  immense  weight  when  all  put  together  (about  52  tons)  is  susceptible  of  easy  transport, 
on  ordinary  artillery  carriages,  over  rough  country,  or  can  be  conveniently  shipped,  stowed, 
or  landed.  Special  mortar  rafts  for  the  use  of  tliese  mortars  at  sea  have  been  designed  by 
their  inventor,  and  novel  and  more  precise  methods  of  pointing,  especially  at  night,  than 
hitherto  practised. 

It  has  been  for  some  time  the  practice  in  Turkey  to  make  field-pieces  like  the  twisted 
barrel  of  a  rifle.  One  of  the  greatest  improvements  in  modern  artillery  is  the  manufacture, 
by  Mr.  G.  W.  Armstrong,  of  Newcastle-on-Tyne,  of  field-pieces  of  this  character,  which  are 
breech-loading,  and  have  several  peculiarities  which  give  them  decided  advantages  over  any 
other  piece  of  artillery.     For  a  further  description,  see  Rifles. 

Exportation  of  arms  and  ammunition  : — 

1852.  18b3. 

Guns       -         -         -     No.        181,121  238,707 

Gunpowder      -         -     lbs.     7,140,133       9,410,891 


1855. 
181,740 
8,576,430 


1856. 
219,630 
10,500,018 

1856. 
cwts.  235 


1854. 

220,952 

8,715,213 

Foreign  and  Colomal, 
Gun  stocks  in  the  rough  of  wood 

ASBESTUS,  from  i.ff^((TTos,  uneonsumable.  (Asbeste,  Fr. ;  Asbc!<t,  Germ.)  When  the 
fibres  of  the  fibrous  varieties  of  amphibole  are  so  slender  as  to  be  flexible,  it  is  called  asbes- 
tus,  or  amianthus.  It  is  found  in  Piedmont,  Savoy,  Salzburg,  the  Tyrol,  Dauphine,  Hun- 
gary, Silesia  ;  also  in  Corsica  so  abundantly  as  to  have  been  made  use  of  by  Dolomieu  for 
packing  minerals ;  in  the  United  States,  St.  Kevern  in  Cornwall,  in  Aberdeenshire,  in  some 
of  the  islands  north  of  Scotland,  and  Greenland.  Asbestus  was  manufactured  into  cloth  by 
the  ancients,  who  were  well  acquainted  with  its  incombustibility.  This  cloth  was  used  for 
napkins,  which  could  be  cleansed  by  throwing  them  into  the  fire  ;  it  was  also  used  as  the 
wick  for  lamps  in  the  ancient  temples ;  and  it  is  now  used  for  the  same  purpose  by  the  na- 
tives of  Greenland.  It  has  been  proposed  to  make  paper  of  this  fibrous  substance,  for  the 
preservation  of  important  matters.  An  Italian,  Chevalier  Aldini,  constructed  pieces  of 
dress  which  are  incombustible.  Those  for  the  body,  arms,  and  legs,  were  formed  out  of 
strong  cloth  steeped  in  a  solution  of  alum  ;  while  those  for  the  head,  hands,  and  feet,  were 
made  of  cloth  of  asbestus.  A  piece  of  ancient  asbestus  cloth,  preserved  in  the  Vatican, 
appears  to  have  been  formed  by  mixing  asbestus  with  other  fibrous  substances ;  but  M. 
Aldini  has  executed  a  piece  of  nearly  the  same  size,  which  is  superior  to  it,  as  it  contains 
no  foreign  substance.  The  fibres  were  prevented  from  breaking  by  the  action  of  steam. 
The  cloth  is  made  loose  in  its  fabric,  and  the  tlireads  are  about  the  fiftieth  of  an  inch  in 
diameter.  The  Society  of  Encouragement,  of  Paris,  has  proposed  a  prize  for  the  improve- 
ment of  asbestus  cloth.     The  use  of  it  is  now  (1858)  being  exhibited  in  London. 

ASHES.  In  commerce,  the  word  ashes  is  applied  to  the  ashes  of  vegetable  substances 
from  which  the  alkalies  are  obtained,  as  Kelp,  Barilla,  &c.,  (which  see.) 

It  is  the  popular  name  of  the  vegetable  alkali,  potash,  in  an  impure  state,  as  procured 
from  the  ashes  of  plants  by  lixiviation  and  evaporation.  The  plants  which  yield  the  great- 
est quantity  of  potash  are  wormwood  and  furmitory.  See  Potash,  Pearlash,  and  for  the 
mode  of  determining  the  value  of  ashes.  Alkalimetry. 

Our  Importations  of  the  various  kinds  of  Ashes  were — 
1855.  1856. 

Soap  ashes,     cwts.     258  . 

Wood  ashes,     "  26         -       cwts.   1,073  (vedasse,  Fr.  ;  waidasche,  Germ.) 

Weed  ashes,     "  -         -  "         380 

Unenumerated  ditto,  value  £5,302  £7,131 ; 

and  of  pearl  and  pot  ashes  as  follows  : — 


Coantries  from  which  imported. 

1S53.         1          lSo4.                   1S55.                   1S5G. 

Russia  ------ 

Holland 

Tuscany         ..... 
British  North  America  - 
United  States         .... 
Prize  cargoes         .         .         -         - 
Other  parts 

Cwts. 
37,604 
6,881 
1,854 
98,774 
10,398 

228 

Cwts. 
9U0 

3,004 
80,080 
18,334 

807 

Cwts. 

71,344 
6,473 

109 

207 

Cwts. 
3,671 

2,224 
87,246 
11,673 

1,127 

155,739     j    109,791 

78,133     1    105,941      1 

ASPHALTUM. 


121 


ASHES  OF  PLANTS.  The  ashes  of  all  species  of  woods  and  weeds  are  found  to  con- 
tain some  alkali,  hence  it  is  that  the  residuary  matter,  after  the  combustion  of  any  vege- 
table matter,  is  found  to  act  as  a  stimulant  to  vegetable  growth. 

The  following  analyses  of  the  ashes  of  plants  have  been  selected  from  the  tables  which 
have  been  published,  by  Messrs.  Thomas  Way  and  G.  Ogston,  in  the  "  Journal  of  the  Agri- 
cultural Society  " : — 


Red 

Sain- 

Wheat 

Straw.  1  Barley. 

Turnip 

Turnip 

Beet 

Carrot 

Clover. 

foin. 

Grain. 

Root. 

Leaves 

Root. 

Root. 

I'otassa 

42-43 

36-72 

18-44 

31-90 

29-76 

10-51  i  20-07 

17-70 

23-70 

11 -.'56 

21-63 

37-55 

Soda  - 

3-27 

0-14 

2-79 

.     . 

5-26 

1-03      4-56 

8-84 

14-75 

12-43 

313 

12-63 

Lime 

5T3 

12-06 

3.J-02 

24-30 

2-8S 

5-91      1-43 

3-54 

11-82 

28-49 

1-90 

9-76 

Magnesia   - 

5  92 

6-00 

11-91 

5-03 

11-06 

1'25  1    7-45 

7-33 

3-28 

2-62 

1-79 

3  7s 

Sesquioxide  of  iron 

0-4^1 

065 

0-9S 

0-61 

0-23 

0-07  1    0-51 

0  49 

0-47 

3  02 

0-52 

0-74 

Sulphuric  acid   - 

6-23 

4-23 

3-91 

3-2S 

Oil 

2  14  1    0-79 

1-10 

16-13 

10-36 

314 

634 

Silica 

1-74 

1-62 

4-03 

3-22 

2-23 

73  57  ,  32-73 

33-43 

2-69 

8-04 

140 

0(6 

Carbonic  acid    - 

4.38 

1-63 

12-92 

15-20 

0-23 

.    - 

-    . 

.    . 

10  47 

6-18 

15-23 

15-15 

Phosphoric  acid 

29-92 

33-74 

5-82 

9-35 

48-21 

5-51 

31-69 

26-46 

9-31 

4-85 

1-65 

8-37 

Chloride  of  potas- 

sium 

•    - 

-    - 

-    - 

6-24 

-     - 

-    - 

-    - 

0-92 

-    - 

-    - 

-    - 

-    - 

Chloride  of  sodium 

-    - 

3-26 

413 

0-73 

-    - 

-    - 

-    - 

-    - 

7-05 

12-41 

49-51 

4-91 

Total  amount    - 

99-96 

100-00 

99-95 

99-90 

99-9G 

99-99     99-98 

99-96 

99-93 

99-96 

99  96 

99-99 

Percentage  of  ash 

in  the  dry  sub- 

stance    - 

2-60 

2-90 

7-87 

6-37 

2-05 

.     . 

2-50 

2-50 

6.00 

16-40 

11-32 

512 

Percentage  of  ash 

in  the  tresh  sub- 

stance    - 

2-24 

2-54 

677 

5-65 

1-81 

-    - 

2-25 

2-27 

0-75 

1-97 

1-02 

0-77 

ASPHALTIC  MASTIC,  used  in  Paris  for  large  works,  is  brought  down  the  Rhone  from 
Pyrimont,  near  Lyssell.  It  is  composed  of  nearly  pure  carbonate  of  lime,  and  about  9  or 
10  per  cent,  of  bitumen. 

When  in  a  state  of  powder  it  is  mixed  with  about  Y  per  cent,  of  bitumen  or  mineral 
pitch,  found  near  the  same  spot.  The  powdered  asphalt  is  mixed  with  the  bitumen  in  a 
melted  state  along  with  clean  gravel,  and  consistency  is  given  to  pour  it  into  moulds.  Sul- 
phur added  to  about  1  per  cent,  makes  it  very  brittle.  The  asphalt  is  ductile,  and  has  elas- 
ticity to  enable  it,  with  the  small  stones  sifted  upon  it,  to  resist  ordinary  wear.  Walls 
having  cracked,  and  parts  having  fallen,  the  asphalte  has  been  seen  to  stretch  and  not  crack. 
It  has  been  regarded  as  a  sort  of  mineral  leather.  The  sun  and  rain  do  not  appear  to  affect 
it ;  and  it  answers  for  abattoirs  and  barracks,  keeps  vermin  down,  and  is  uninjured  by  the 
kicking  of  horses. 

A  large  roof  has  been  formed  in  Paris  for  a  store  for  the  Government  food,  entirely  of 
earthenware  tiles,  and  without  timber,  the  tiles  being  9  inches  long  and  5  wide.  The  arch 
is  covered  with  a  concrete  of  lime,  sand,  and  gravel ;  then  with  a  thin  coat  of  hydraulic 
mortar ;  over  this,  when  dry,  canvas  was  tightly  stretched  ;  asphaltic  mastic  was  poured  in 
a  semi-fluid  state,  and  this  formed  the  finished  surface  of  the  roof.  The  strength  of  the 
roof  has  been  purposely  tested  to  bear  six  tons  without  yielding,  and  has  borne  the  acci- 
dental fall  of  a  stack  of  chimneys,  with  the  only  effect  of  bruising  the  mastic,  readily 
repaired. 

ASPHALTUM.  {Bitmne  or  Asphalte^  Fr. ;  Asphalt^  Germ.)  Mineral  Pitch ;  so 
called  from  the  lake  Asphaltites  ;  a  variety  of  bitumen,  arising  from  one  of  the  many  pecu- 
liar changes  of  vegetable  matter.  Asphaltura,  in  common  with  other  varieties  of  bitiunon, 
is  a  form  of  hydrocarbon  produced  in  the  interior  of  the  earth  by  the  transformation  of 
carbonaceous  matter,  like  all  combustible  bodies  of  the  same  class.  Composition,  C^'IV". 
It  is  a  solid  black  or  brownish-black  substance,  possessing  a  bright  conchoidal  fracture.  It 
fuses  at  212'  F.,  burning  with  a  brilliant  flame,  and  emitting  a  bituminous  odor.  Specific 
gravity  r=  1  to  1-2.  Asphaltum  is  insolul)Ie  in  alcohol,  but  soluble  in  about  five  times  its 
weight  of  naphtha.     See  Bitumen, 

Tliis  solid  shining  bitumen,  of  a  deep  black  color  when  broken,  is  found  in  many  parts 
of  Egypt.  A  thin  piece  appears  of  a  reddish  color  when  held  to  the  light ;  when  cold,  it 
has  no  odor  ;  by  a  moderate  heat  or  by  friction,  the  odor  is  slight ;  fully  heated,  it  Ii(iuo- 
fies,  swells,  and  burns  with  a  thick  smoke ;  the  odor  given  is  acrid,  strong,  and  dis- 
agreeable. 

Spirits  of  wine  dissolves  pitch,  but  only  takes  a  pale  color  with  asphaltum.  It  is  readily 
procured  at  Mocha. 

In  the  arts,  asphaltum  is  used  as  a  component  of  japan  varnish.  It  is  likewise  em- 
ployed as  a  cement  for  lining  cisterns,  and  for  pavements,  as  a  substitute  for  flag-stones. — 
H.  W.  B. 

The  following  quantities  of  Asphaltum,  or  Bitumen  Judaicum,  were  imported  into 
Great  Britain : — in  1855,  1,67-i  tons;  in  1S56,  2,707  tons,  of  which  2,573  tons  were  from 
France. 


122  ASSAY  AND  ASSAYING. 

ASSAY  and  ASSAYING.  The  process  employed  in  assaying  gold  bullion,  by  the  pres- 
ent assayers  to  the  Mint  and  Bank  of  England,  is  similar  to  that  practised  at  the  Paris  Mint. 
The  quantity  operated  on  is  half  a  gramme.  Tliis  quantity,  having  been  accurately  weighed, 
is  wrapped  in  paper  with  a  portion  of  pure  silver,  about  equal  to  three  times  that  of  the 
gold  the  alloy  is  supposed  to  contain,  and  submitted  to  cupellation  with  lead  in  the  manner 
described  in  vol.  i.  The  button  is  then  hammered  into  a  flattened  dish,  about  the  size  of  a 
sixpence,  and  afterwards  annealed  and  passed  through  laminating  rolls  until  it  is  reduced  to 
a  riband  from  2i  to  3  inches  in  length  ;  after  which  it  is  again  annealed,  and  coiled  into  a 
spiral  by  rolling  between  the  finger  and  thumb.  The  cornet  is  next  placed  in  a  small  flask 
containing  about  an  ounce  of  pure  nitric  acid  of  22  B.,  (=  I'lSO  specific  gravity,)  and 
boiled  for  10  minutes.  The  acid  is  carefully  poured  off,  and  the  cornet  again  boiled  with 
nitric  acid  of  32  B.  (1-280  specific  gravity)  for  20  minutes;  and  this  second  boiling  with 
the  stronger  acid  is  repeated  and  continued  about  10  minutes.  In  the  second  and  third 
boilings  a  small  piece  of  charcoal  should  be  introduced  into  the  flask,  as  recommended  by 
Gay-Lussac,  in  order  to  prevent  the  ebullition  taking  place  irregularly  and  with  sudden 
bursts,  which  would  be  liable  to  break  the  cornet,  and  eject  a  portion  of  the  liquid  from  the 
flask.  The  cornet  is  then  washed  and  annealed  as  above.  The  return  is  made  to  the  Mint 
in  decimals  or  thousandths,  and  the  assayer's  weights  are  so  subdivided  as  to  give  him  the 
value  in  thousandths  of  the  original  ^  gramme  taken. 

To  the  Bank  the  return  is  made  to  the  i  of  a  carat  grain  better  or  worse  than  standard. 
The  late  Master  of  the  Mint  caused  Tables  to  be  prepared  for  the  conversion  of  the  reports 
of  assays  expressed  in  carats  into  decimals,  and  conversely,  which  are  in  general  use  for 
this  purpose.  In  order  to  ascertain  the  amount  of  error  due  to  the  surcharge,  a  number  of 
proofs  are  passed  through  the  process  simultaneously  with  the  alloys.  These  proofs  con- 
sist of  weiglied  portions  of  absolutely  pure  gold,  to  which  is  added  a  proportion  of  cop- 
per equal  to  that  estimated  to  exist  in  the  alloy  to  be  assayed.  The  excess  of  weight  in 
these  proofs  gives  the  amount  to  be  deducted.  It  generally  varies  from  0'2  to  0-5  parts 
in  1,000. 

The  last  traces  of  silver  may  be  removed  from  the  cornet  by  treating  it  before  the  final 
annealing  with  fusing  bisulphate  of  potash  in  a  porcelain  crucible.  When  sufficiently  cool, 
the  whole  is  heated  with  hot  water  containing  a  little  sulphuric  acid,  and  the  comet  dried 
and  ignited.  By  this  means  gold  may  be  obtained  of  almost  absolute  purity,  or  '"""/looo,  as 
it  is  termed. 

The  following  examples  will  show  the  difference  in  the  results,  and  the  degree  of  accu- 
racy attainable,  by  the  various  methods  described  : — 

Ten  grains  of  pure  gold,  alloyed  with  three  times  its  weight  of  silver,  cupelled  and 
boiled  with  acid  at  22"  B.,  and  32°  B.,  once  weighed  10-016. 

Ten  grains  of  a  half-sovereign,  with  silver,  &c.,  and  acid  at  22°,  and  twice  at  32°  B., 

gave    915*4 

again,  915"6 

With  acid,  as  before,  and  bisulphate  of  potash,  915-2 

again,  915-2 

Pure  gold  alloyed  with  copper,  to  bring  it  to  standard,  cupelled  with  silver  and  lead, 
and  treated  with  acids  and  bisulphate,  gave  in  one  case  precisely  the  same  as  was  taken 
originally,  or  '™7iooo,  and  in  another  999-98. 

In  accurate  assaying  of  gold  bullion,  it  is  of  course  absolutely  necessary  that       47 
the  acids  should  be  pure,  and  that  the  silver  used  should  be  most  carefully  freed  \:^;;^ 
from  the  traces  of  gold  which  it  usually  contains. 

Instead  of  charcoal  or  coke,  which  are  generally  used  for  cupellation,  much 
advantage  has  been  found  in  employing  the  best  anthracite  :  reduced  to  the  prop- 
er size,  it  contains  very  little  ash,  is  free  from  slag  or  clinker,  and  allows  the  heat 
to  be  maintained  at  one  steady  temperature  for  many  hours,  which  is  a  matter  of  \ 
great  importance  to  the  assayer.* 

ASTRAGAL.  An  ornamental  moulding,  generally  used  to  conceal  a  junction 
in  either  wood  or  stone. 

ASTRAGAL  PLANES.  Pianos  fitted  with  cutters  for  forming  astragal  mould- 
ings.    They  ar^commonlv  known  as  moulding  planes. 

ASTRAGAL  TOOL,  for  turning.  By  using  a  tool  shaped  as  in  f(j.  41,  the 
process  of  forming  a  moulding  or  ring  is  greatly  facilitated,  as  one  member  of 
the  moulding  is  completed  at  one  sweep,  and  we  are  enabled  to  repeat  it  any 
number  of  times  with  exact  uniformity. 

*  The  most  useful  works  on  this  subject  nrn: — Chnu'let,  "L'Art  do  VEssaycur  ; "  the  work  of  G.ny- 
Lussac  montioned  in  the  text ;  "Mannel  complet  de  TKssayeur,"  par  Vauquelin  and  D'Arcct,  edited  by 
Versnaud.  Paris,  18.3G,  (a  most  useful  little  work:)  Bodemann,  "Anlcitung  zur  Berc-  und  Tluttenm.an- 
nischen  Probierkunst,"  Claiisthal,  1S45;  and  (perhaps  the  best  of  them  all)  the  "Scheikundig  llandbock 
Voor  Ess-iijeurs  Goud  und  Zilverstnedcn"  by  Stratingh,  Groningen,  1821. 


ATOMIC  THEORY.  123 

ATOMIC  THEORY.  Dr.  Dalton  suggested  the  happy  idea,  which  has  been  most  fruit- 
ful ill  its  results,  of  accounting  for  the  constancy  of  chemical  combinations  by  assuming  that 
they  were  composed  of  one  or  more  atoms  of  the  several  elements,  the  weight  of  wliich 
atoms  is  represented  by  the  combining  proportions ;  that  carbonic  oxide,  for  instance,  con- 
tains single  atoms  of  carbon  and  oxygen,  whilst  carbonic  acid  is  composed  of  one  atom  of 
carbon  and  two  of  oxygen. 

It  must  always  be  remembered  that  the  combining  proportions  are  purely  the  results 
of  experiment,  and,  therefore,  incontestable,  whatever  may  be  the  fate  of  this  theory, 
which,  however,  has  now  stood  its  ground  for  many  years,  and  done  excellent  service  to 
science. 

This  theory  offers  a  most  satisfactory  explanation  of  the  different  laws  of  chemical  com- 
bination. 

The  fact  of  bodies  uniting  only  in  certain  proportions,  or  multiples  of  those  proportions, 
is  a  necessary  consequence  of  the  assumption  that  the  weight  of  the  elementary  atoms  is 
represented  by  the  combining  proportions  ;  for,  if  they  united  in  any  other  ratio,  it  would 
involve  the  splitting  up  of  these  atoms,  which  are  assumed  to  be  indivisible. 

And,  of  course,  the  combining  proportion  of  a  compound  must  be  the  sum  of  the  com- 
bining proportions  of  the  constituents,  since  it  contains  within  itself  one  or  more  atoms  of 
the  several  constituents. 

The  term  atom  is,  therefore,  very  often  used  instead  of  combining  proportion  or  equiva- 
lent, a  body  being  said  to  contain  so  many  atoms  of  its  elements. 

All  that  is  assumed  in  this  theory  is,  that  the  atoms  are  of  constant  value  by  weight ; 
the  same  atoms  may  be  arranged  in  a  different  way,  and  hence,  although  any  particular 
compound  contains  always  the  same  elements  in  the  atomic  ratios,  yet  the  same  atoms  may, 
by  difference  in  arrangement,  give  rise  to  bodies  agreeing  in  composition  by  weight,  but 
differing  essentially  in  properties. 

M.  Dumas  has  suggested  the  subdivision  of  the  combining  numbers  of  certain  elements, 
but  this  idea  is  quite  subversive  of  the  atomic  theory,  as  it  is  at  present  understood. 

The  atomic  theory  is  further  confirmed  by  the  observation,  that  if  the  specific  heat  of 
the  elements  be  compared,  it  is  found  that  in  a  large  number  of  cases  the  specific  heat  of 
quantities  of  the  bodies  represented  by  the  atomic  weights  coincides  with  each  other  in  a 
remarkable  manner. 

The  Atomic  Theory  of  Dalton  is  thus  set  forth  by  the  author : — 

"  When  any  body  exists  in  tlie  elastic  state,  its  ultimate  particles  are  separated  from 
each  other  to  a  much  greater  distance  than  in  any  other  state  ;  each  particle  occupies  the 
centre  of  a  comparatively  large  sphere,  and  supports  its  dignity  by  keeping  all  the  rest — 
which,  by  their  gravity,  or  otherwise,  are  disposed  to  encroach  on  it — at  a  respectful  dis- 
tance. When  we  attempt  to  conceive  the  number  of  particles  in  an  atmosphere,  it  is  some- 
what like  attempting  to  conceive  the  number  of  stars  in  the  universe — we  are  confounded 
with  the  thought.  But  if  we  limit  the  subject,  by  taking  a  given  volume  of  any  gas,  we 
seem  persuaded  that,  be  the  divisions  ever  so  minute,  the  number  of  particles  must  be 
finite ;  just  as  in  a  given  space  of  the  universe,  the  number  of  stars  and  planets  cannot  be 
infinite. 

"  Chemical  analysis  and  synthesis  go  no  further  than  to  the  separation  of  particles  one 
from  another,  and  to  their  reunion.  No  new  creation  or  destruction  of  matter  is  within  the 
reach  of  chemical  agency.  We  might  as  well  attempt  to  introduce  a  new  planet  into 
the  solar  system,  or  to  annihilate  one  already  in  existence,  as  to  create  or  destroy  a  par- 
ticle of  hydrogen.  All  the  changes  we  can  produce  consist  in  separating  particles  that 
are  in  a  state  of  cohesion  or  combination,  and  joining  those  that  were  previously  at  a  dis- 
tance. 

"  In  all  chemical  investigations  it  has  justly  been  considered  an  important  object  to 
ascertain  the  relative  weight!^  of  the  simples  which  constitute  a  compound.  But,  unfortu- 
nately, the  inquiry  has  terminated  there  ;  whereas,  from  the  relative  weights  in  the  mass, 
the  relative  weights  of  the  ultimate  particles  or  atoms  of  the  bodies  might  have  been 
inferred,  from  wliich  their  number  and  weights  in  various  other  compounds  would  appear, 
in  order  to  assist  and  to  guide  future  investigations,  and  to  correct  their  results.  Now  it  is 
one  great  object  of  this  work  ('  A  New  System  of  Chemical  Philosophy ')  to  show  tlie  im- 
portance and  advantage  of  ascertaining  the  relative  weights  of  the  ultimate  particles,  both 
of  simple  and  compound  bodies,  the  number  of  simple  elcwentary  particles  w/iich  cwistitulc 
one  compound  particle,  and  the  intmber  of  less  compound  particles  which  enter  into  the 
formation  of  each  more  compound  particle.'''' 

For  a  full  examination  of  this  subject,  consult  "  An  Introduction  to  the  Atomic  Theory," 
by  Charles  Daubeny,  M.D.  ;  and  "  Memoirs  of  John  Dalton  and  History  of  the  Atomic 
Theory,"  by  Robert  Angus  Smith,  V\\.  D. 

The  following  Table  will  show  the  quantity  of  precipitate  that  may  be  expected  to  result 
from  the  addition  of  nitrate  of  silver  to  100  grain.'i  of  a  salt  of  sodium,  according  to  the 
proportion  of  chloride  and  of  bromide  present : — 


124 


ATOMIC  WEIGHTS. 


Quantity  of  Salt. 

Quantity  of 
Precipitate. 

Quantity  of  Salt. 

Quantity  of 
Precipitate. 

Amount  of  Precipi- 
tate from  the  two 
Salts. 

Br.  Sodium. 

Br.  Silver. 

Ch.  Sodium. 

Ch.  Silver. 

luo 

184-5 

0 

0 

184-5 

90 

166-0 

10 

24-3 

190-3 

80 

148-0 

20 

48-3 

196-3 

70 

129-5 

30 

73-0 

202-0 

60 

111-0 

40 

95-5 

208-5 

50 

92-5 

50 

121-5 

214-0 

40 

74-0 

60 

146-0 

220-0 

30 

56-0 

70 

170-0 

226-0 

20 

37-0 

80 

195-0 

2320 

10 

18-5 

90 

219-0 

237-5 

0 

00-0 

100 

243-0 

243-0 

ATOMIC  WEIGHTS,  EQUIVALENT,  CHEMICAL  EQUIVALENT,  COMBINING 
WEIGHT,  or  PROPORTION.  The  following  propositions  may  be  regarded  as  the  Liws 
regulating  atomic  combination  : — 

1.  The  equivalents  of  elementary  bodies  represent  the  smallest  proportions  in  uhich  they 
enter  into  couibination  with  each  other. 

2.  The  equivalent  of  a  compound  body  is  the  sum  of  the  equivalents  of  its  elements. 

3.  Combination  takes  place,  tvhcther  between  elements  or  compounds,  either  in  the  pro- 
portions of  their  equivalents,  or  in  multiples  of  these  projjortions,  and  never  in  sub- 
tmdtiples, 

4.  The  law  of  definite  and  multiple  proportion  is,  individual  compounds  cduays  contain 
exactly  the  same  proportions  of  their  elc7ncnts.     See  Equivalents,  Chemical. 

ATOMIC  VOLUMES.  Rcccntlj'  it  has  been  assumed  that  the  elements  unite  invariably 
in  equal  volumes — when  in  the  gaseous  state  ; — or,  in  other  words,  that  the  atoms  of  bodies 
have  always  the  same  volume.  If  this  doctrine  be  maintained,  it  becomes  necessary  to  alter 
tlie  atomic  weights  or  combining  numbers  of  certain  elements.  For  example,  water  con- 
tains two  volumes  of  hydrogen  to  one  of  oxygen  ;  but,  according  to  the  generally  received 
idea,  it  consists  of  single  atoms  of  each  element ;  it  is  clear,  therefore,  that  if  we  are  to 
assume  that  the  atoms  of  hydrogen  and  oxygen  have  the  same  volume,  we  must  either 
halve  the  atomic  weight  of  hydrogen  or  double  that  of  oxygen. 

Bcrzclius  suggested  that  all  the  atomic  weights  should  remain  the  same,  except  those 
of  hydrogen,  nitrogen,  phosphorus,  chlorine,  bromine,  and  iodine,  which  should  halve  their 
present  value.  Gerhardt,  on  the  other  hand,  adopts  the  more  convenient  practice  of  allow- 
ing hydrogen  and  its  congeners  to  retain  their  present  atomic  weights,  doubling  those  of 
oxygen,  sulphur, -tellurium,  and  carbon. 

ATROPINE.  (C^'IP'NO".)  An  exceedingly  poisonous  alkaloid,  found  in  deadly  night- 
shade (Atropa  Belladonn)  and  in  stramonium  (Datura  Stramonium.) 

ATTAR  OF  ROSES,  more  commonly,  OTTO  OF  ROSES.  An  essential  oil,  obtained 
in  Indin,  Turkey,  and  Persia,  from  some  of  the  finest  varieties  of  roses.  It  is  procured  l)y 
distilling  rose  leaves  with  water,  at  as  low  a  temperature  as  possible.  It  is  said  that  this 
perfume  is  prepared  also  by  exposing  the  rose  leaves  in  water  to  the  sun ;  but,  from  the 
fact  that  under  the  circumstances  fermentation  would  be  speedily  established,  it  is  not 
probable  that  this  is  a  method  often  resorted  to.  By  dry  distillation  from  salt-water 
baths,  no  doubt  the  finest  attar  is  obtained.  This  essential  oil  is  only  used  as  a  perfume. 
Attar  of  roses  is  adulterated  with  spermaceti  and  with  castor  oil  dissolved  in  strong  alco- 
hol. 

This  adulteration  may  be  detected  by  putting  a  small  drop  of  the  otto  of  roses  on  a 
piece  of  clean  writing  paper ;  by  agitation  in  the  air,  the  volatile  oil  soon  evaporates,  leav- 
ing no  stain  if  pure  ;  if  any  fixed  oil  is  present,  a  greasy  spot  is  left  on  the  paper. 

ATTENUATION.  Brewers  and  distillers  employ  this  term  to  signify  the  weakening  of 
s;iccharine  worts  during  fermentation,  by  the  conversion  of  the  sugar  into  alcohol  and  car- 
bonic acid. 

AURUM  MUSIVUM  or  JIOSAICUif.  Mosaic  Gold.— For  the  preparation  of  Mo.saie 
gold,  the  following  process  is  recommended  by  Woulfe.  An  amalgam  of  2  parts  of  tin  and 
1  part  of  mercury  is  prepared  in  a  liot  crucil)le,  and  triturated  with  1  part  of  sal-ammoniac, 
and  1  part  of  flower  of  sulphur ;  the  mixture  is  sulilimed  in  a  glass  flask  ufion  the 
sand  l)ath.  In  breaking  the  flask  after  the  operation,  the  sublimate  is  found  to  consist, 
superficially,  of  sal-ammoniac,  then  of  a  layer  of  cinnabar,  and  then  of  a  layer  of  Mosaic 
gold. 

There  are  several  other  processes  given  for  the  preparation  of  this  bisulphide  of  tin,  but 
the  above  prol)ably  gives  the  best  results. 


AVOCADO  PEAR  OIL. 


125 


Bergman  mentions  a  native  aui^m  rmisivum  from  Siberia,  containing  tin,  sulphur,  and 
a  small  proportion  of  copper.     Dr.  John  Davy  gave  the  composition  as — 

Tin     -        -        -        -,       -     100      I      Sulphur 
Berzelius  as — 

Tin 100 


56-25 


Sulphur 


52-3 


Mosaic  gold  is  employed  as  a  bronzing  powder  for  plaster  figures,  and  it  is  said  to  enter 
sometimes  into  the  composition  of  aventurine. 

AUTOGENOUS  SOLDERING.  A  process  of  soldering  by  which  metals  are  united 
either  by  the  ordinary  solders  or  by  lead, 

under  the  influence  of  a  flame  of  hydro-  48 

gen  or  of  a   mixture    of  hydrogen   and 
common  air. 

The  process  of  using  air  and  hydro- 
gen was  invented  in  France,  by  the  Count 
de  Richemont.  Hydrogen  gas  is  con- 
tained in  a  gasometer,  to  which  a  flexible 
tube  is  connected,  and  air  is  urged  from 
a  bellows  worked  by  the  foot,  through 
another  tube,  and  on  to  the  blowpipe, 
where  the  hydrogen  is  ignited.  By  means 
of  the  flexible  tubes  the  flame  can  be 
moved  up  and  down  the  line  of  any  joint, 
and  the  connecting  medium  melted.  Fig. 
48. 

This  process  has  been  a  good  deal  employed  for  plumbers'  work,  especially  in  our  naval 
arsenals. 

AUTOMATIC  ARTS.  Such  arts  or  manufactures  as  are  carried  on  by  self-acting  ma- 
chinery. 

AVENTURINE.  {Aventurine,  Fr.)  A  variety  of  quartz  which  is  minutely  spangled 
throughout  with  yellow  scales  of  mica;  is  known  as  Aventurijie  quartz.  It  is  usually 
translucent,  and  of  a  gray,  brown,  or  reddish-brown  color.  There  is  also  an  Aventurine 
felspar  {Feldspath  arenturine,  Fr.)  Commercially,  in  France  and  some  other  parts  of 
Europe,  the  name  of  Pierre  de  soleil  is  given  to  the  finest  varieties  of  the  felspar  aventu- 
rine, some  lapidaries,  however,  calling  this  stone  by  the  name  of  Aventurine  orientale. 
This  aventurine  occurs  at  Capa  de  Gata,  in  Spain ;  it  has*  reddish  and  yellow  internal 
reflections. 

An  artificial  aventurine  has  been  manufactured  on  a  large  scale  for  a  long  period,  at  the 
glass-works  of  Murano,  near  Venice.  According  to  Wohler's  examination,  aventurine  glass 
owes  its  golden  iridescence  to  a  crystalline  separation  of  metallic  copper  from  the  mass 
colored  brown  by  the  peroxide  of  iron. 

C.  Karsten  analyzed  the  artificial  aventurine  from  the  glass  manufactory  of  Bigaglia,  in 
Venice,  and  found  it  to  contain — 

Silicic  acid &1-Z 

Lime 90 

Protoxide  of  iron 3-4 

Binoxide  of  tin 2-3 

Protoxide  of  lead l-Q 

Metallic  copper  •         -         -         -         -         -         -         -         -4"0 

Potash 5-3 

Soda 'J-0 

These  numbers  agree  in  a  remarkable  manner  with  the  results  formerly  obtained  by  Feligot, 
and  may  therefore  be  regarded  as  truly  representing  the  composition  of  the  glass. 

AVERRUNCATOR.  A  pair  of  pruning  shears,  which,  on  being  mounted  on  a  pole 
some  ten  feet  long,  and  actuated  by  a  string  of  catgut,  can  be  used  for  pruning  at «  consid- 
erable distance  above  the  head. 

AVOCADO  PEAR  OIL.  An  oil  obtained  from  the  oleaginous  fruit  the  Avocado  pear- 
tree,  {Lanrus  Pemea,)  a  native  of  Trinidad.  A  portion  of  this  oil  having  been  suljniitted 
to  Dr.  Hofmann  by  the  Governor  of  Trinidad,  he  reported  on  its  character  and  composition. 
The  following  is  an  extract  from  his  report : — 

''  According  to  my  present  experience,  the  oil  of  the  Avocado  pear  is  less  valuable  as  a 
lubricating  material.  To  make  it  fit  for  the  higher  classes  of  machinery,  its  mucilaginous 
constituents  must  be  removed  by  the  same  refining  process  requisite  for  its  adaptation  in 
illuminating  purposes.  This  will  slightly  increase  its  price.  Even  when  purified  it  retains 
an  attraction  for  oxygen,  by  which  it  becomes  rapidly  colored,  viscid,  and  actually  acid.  It 
cannot,  either  in  price  or  in  applicability,  compete  with  that  remarkable  substance  '  Paraf- 


126  AZIMUTH  COMPASS. 

fine  oil,'  which  has  been  discovered  within  the  last  year  by  Mr.  James  Young,  and  which  is 
now  manuiactured  by  him  on  a  large  scale,  by  the  distillation,  at  a  low  temperature,  of  sev- 
eral varieties  of  coal. 

"  On  the  other  hand,  the  oil  of  the  Avocado  pear  is  very  applicable  for  the  production 
of  "ood  soap.  I  have  the  honor  of  transmitting  to  your  Excellency  specimens  prepared 
with  the  oil :  the  smaller  one,  which  possesses  a  yellow  color,  is  prepared  with  the  oil  in  its 
ori-'inal  condition  ;  the  larger  one  is  made  with  a  portion  of  oil  which  had  previously  been 
bleached  by  chlorine.  From  this  specimen  it  is  obvious  that  the  oil,  although  poor  in 
stcurine,  nevertheless  furnishes  a  soap  which  is  tolerably  hard  and  solid.  It  ought  to  be 
remembered  that  it  is  difficult  to  obtain  a  hard  soap  by  working  on  the  small  scale  pre- 
scribed by  the  limited  amount  of  material  at  my  disposal.  For  the  perfect  elaboration  of 
this  investigation  also,  a  large  supply  of  material  will  be  of  great  advantage  ;  but  I  have 
even  now  no  hesitation  in  stating,  that,  for  the  purposes  of  the  soap-maker,  the  oil  of  the 
Avocado  pear  will  have,  at  least,  the  same  value  as  palm  oil." 

AZIMUTH  COMPASS.  The  azimuth  compass  is  used  chiefly  to  note  the  actual  mag- 
netic azimuth,  or  that  arch  of  the  horizon  intercepted  between  the  azimuth,  or  vertical 
circle  passing  through  the  centre  of  any  heavenly  body,  and  the  magnetic  meridian. 

The  card  of  the  azimuth  compass  is  subdivided  into  exact  degrees,  minutes,  and  seconds. 
To  the  box  is  fixed  two  "  sights,"  through  which  the  sun  or  a  star  may  be  viewed.  The 
position  into  which  the  index  of  the  sights  must  be  turned  to  see  it,  will  indicate  on  the 
card  the  azimuth  of  the  star.  When  the  observations  are  intended  to  be  exact,  telescopes 
take  the  place  of  the  sights.  By  this  instrument  we  note  the  actual  magnetic  azimuth ; 
and,  as  we  know  the  azimuth  calculated  from  the  N.  and  S.  line,  the  variation  of  the  needle 
is  readily  found. 

AYR  STONE,  called  also  Scotch  stone  and  snake  stone,  is  much  in  request  as  a  polish- 
ing stone  for  marble  and  for  copper  plates.  These  stones  are  always  kept  damp,  or  even 
wet,  to  prevent  their  becoming  hard. 

The  harder  varieties  of  Ayr  stone  arc  now  employed  as  whetstones. 

AZURITE.  This  term  has  been  applied  to  several  blue  minerals,  which  have  little  in 
common.  Beudant  and  Dana  use  it  to  signify  the  blue  carbonate  of  copper — now  termed 
Chessylite  by  Brook  and  Miller,  from  its  occurring  in  fine  crystalline  forms  at  Chessy,  near 
Lyons ;  hence  commonly  called  Chessy  copper. 

Azurite  is  also  applied  to  the  Lazulitc  of  Dana  ;  which  is  again  called  Azure  stone  and 
blue  spar  by  others. 

The  same  term  is  also  given  to  the  Lapis  lazuli,  from  which  ultramarine  is  obtained. 

This  want  of  agreement  'between  mineralogists — leading  them  to  adopt  names  inde- 
pendefit  one  of  the  other  (names  frequently  taken  from  some  locality  in  which  the  writer 
knows  the  mineral  to  be  found) — produces  great  confusion,  and  retards  the  progress  of 
knowledge. 

B 

BACK.  A  mining  term.  The  back  of  a  mineral  lode  is  that  part  which  is  nearest  the 
surface.     The  back  of  a  level  is  the  ground  between  it  and  the  level  above  it. 

BACK.     A  brewer's  utensil. 

BAIN-MARIE.     A  vessel  of  water  in  which  saucepans,  &c.,  are  placed  to  warm  food. 

BAIZE.     A  coarse  woollen  stuff  with  a  long  nap,  sometimes  frized  on  one  side. 

BAKERS'  SALT.  The  sesquicarbonate  of  ammonia,  so  called  because  it  is  often  used 
as  a  substitute  for  yeast  in  bread  and  pastry. 

BAL.  An  ancient  Cornish  miner's  term  for  a  mine.  Bal-maidcns  is  a  name  given  to 
girls  working  at  a  mine. 

BAL.VCIIONG.  An  article  of  food  much  used  in  the  Eastern  Archipelago,  consisting 
of  fish  and  slu-imps  pounded  together. 

BALANCE  FOR  WEIGHING  COIN  introduced  at  the  Bank  of  England  in  the  year 
1841. 

Mr.  William  Cotton,  then  Deputy-Governor,  and  during  the  two  succeeding  years  Gov- 
enior  of  the  Bank,  had  long  regarded  the  mode  of  weighing  by  common  hand-balances  with 
dissatisfaction  on  account  of  its  injurious  effect  upon  the  "  teller,"  or  weigher,  owing  to  the 
straining  of  the  optic  nerve  by  constant  watching  of  the  beam  indicator,  and  the  necessity 
of  reducing  the  functions  of  the  mind  to  the  narrow  office  of  influencing  a  few  constantly 
repeated  actions.  Such  monotonous  labor  could  not  be  endured  for  hours  together  without 
moments  of  forgetfulness  resulting  in  errors.  Errors  more  constant,  although  less  in 
amount,  were  found  to  lie  due  to  the  rapid  wearing  of  the  knife-edges  of  tlie  beam  ;  cur- 
rents of  air  also  acting  upon  the  pans  produced  undcsired  results  ;  and  even  the  breath  of 
the  "teller"  .«omctimcs  turned  the  scale;  so  that,  in  hand-weighing,  the  errors  not  unfre- 
quently  amounted  to  ^,  and  even  \  grain.  At  the  very  best,  the  hand-scale  working  at  the 
rate  of  3,000  per  six  hours  could  not  indicate  nearer  than  Vjs  grain. 


BALANCE  FOR  WEIGHING  COIN.  12T 

Upon  taking  into  consideration  the  inconveniences  and  defects  of  the  hand-weighing 
system,  Mr.  Cotton  conceived  the  idea  that  it  might  be  superseded  by  a  machine  defended 
from  external  influences,  and  contrived  so  as  to  weigh  coins  as  fast  as  by  hand,  and  within 
the  fourth  of  a  grain,  lie  subsequently  communicated  his  plan  to  Mr.  David  Napier,  of 
York  Road,  Lambeth,  engineer,  who  undertook  the  construction  of  an  experimental  ma- 
chine. Its  capabilities  were  tested  and  reported  upon  by  Mr.  William  Miller,  of  the  Bank. 
The  result  was  most  satisfactory  ;  more  "  automaton  balances  "  were  ordered  ;  and  fr(jin 
time  to  time  further  additions  have  been  made,  so  that  at  present  there  are  ten  in  daily 
operation  at  the  Bank  of  England.  But  it  was  not  without  a  struggle  that  the  time  halloweil 
institution  of  tellers  passed  away.  There  were  interests  opposed  to  the  introduction  of 
improved,  more  ready,  and  less  expensive  methods ;  and  it  required  all  Mr.  Cotton's  energy 
of  character,  the  influence  of  his  intelligence  in  mechanics,  as  well  as  that  arising  from  his 
position  in  the  Direction,  to  obtain  the  adoption  of  an  invention  by  which  a  very  large 
annual  saving  has  been  effected. 

The  mechanical  adaptation  of  the  principles  involved  in  the  Automaton  Balance,  as  con- 
trived by  Mr.  Napier,  may  be  shortly  explained : — The  weighing  beam,  of  steel,  is  forked 
at  the  ends,  each  extremity  forming  a  knife  edge  ;  and  in  the  centre  the  fulcrum  knife-edge 
extends  on  each  side  of  the  plate  of  the  beam,  and  rests  in  hollows  cut  in  a  bowed  cross- 
bar fixed  to  the  under  side  of  a  rectangular  brass  plate,  about  12  inches  square,  which  is 
supported  at  the  corners  by  columns  fixed  to  a  cast-iron  table  raised  a  convenient  height  on 
a  stand  of  the  same  metal.  To  form  a  complete  enclosing  case,  plates  of  metal  or  glass  are 
slid  into  grooves  down  the  columns.  Wlien  the  beam  is  resting  with  its  centre  knife-edge 
in  the  hollows  of  the  cross-bar  just  referred  to,  its  upper  part  is  nearly  on  a  level  with  the 
under  side  of  the  brass  plate,  in  which  a  long  slot  is  made  so  that  the  beam  can  be  taken 
out  when  the  feeding  slide-box,  and  its  plate,  which  covers  tliis  slot,  are  removed.  On  the 
top  of  the  covering  plate  of  the  feeding  slide  a  tube  hopper  is  placed,  and  a  hole  in  the 
plate  communicates  with  the  slide ;  another  hole  is  pierced  in  the  same  plate  exactly  over 
one  end  of  tlie  beam,  upon  the  knife-edges  of  which  a  long  rod  is  suspended  by  hollows 
formed  in  a  cross-bar  close  to  its  upper  end,  where  the  weighing  platform  is  fitted.  A  rod 
is  also  suspended  at  the  other  end  of  the  beam  in  a  similar  manner ;  but  instead  of  a  weigh- 
ing plate,  it  has  a  knob  at  top,  which,  when  the  beam  is  horizontal,  comes  into  contact  with 
an  adjustable  agate  point.  The  lower  end  of  this  pendant  rod  is  stirrup-shaped,  for  holding 
the  counterpoise.  Two  displacing  slides  are  provided,  one  on  each  side  of  the  feeding  slide, 
and  at  right  angles  to  each  other;  and  a  gripping  apparatus  is  fixed  to  the  under  side  of  the 
brass  top  plate,  arranged  so  as  to  hold  the  pendant  on  which  the  scale-plate  is  fitted  during 
the  change  of  the  coin.  A  dipping-finger  is  also  attached  to  the  frame  of  the  gripping 
apparatus,  its  end  passing  into  a  small  slot  in  the  pendant  rod,  and  acting  upon  a  knife-edge 
at  the  lower  end  of  the  slot.  There  are  four  shafts  crossing  the  machine  ;  the  one  through 
which  the  power  is  applied  is  placed  low  and  at  the  centre,  and  carries  a  pinion  which  gears 
with  a  wheel  of  twice  its  diameter  on  a  shaft  above ;  this  wheel  gears  with  two  similar 
wheels  fixed  to  shafts  on  each  side  of  the  centre.  Cams  for  acting  upon  the  feeding  slide 
through  the  medium  of  a  rocking  frame,  are  carried  by  the  shaft  placed  at  the  end  of  the 
machine  where  the  counterpoise  hangs,  and  the  other  two  shafts  on  the  same  level  bear 
cams  for  working  the  gripping  apparatus,  the  dipping-finger,  and  the  displacing  slides. 

Having  described,  as  clearly  and  as  popularly  as  we  can,  the  general  features  of  the 
mechanism,  we  will  proceed  to  indicate  its  manner  of  action.  Suppose,  then,  the  hopper 
filled,  and  a  hollow  inclined  plane  about  two  feet  long,  which  has  been  added  to  the  hopper 
by  the  inventive  genius  of  one  of  the  gentlemen  in  the  weighing-room,  also  loaded  its 
whole  length  with  the  pieces  to  be  weighed,  the  machine  is  set  in  motion,  and  the  feeding 
slide  pushes  the  lowest  piece  forward  on  to  the  weighing  plate,  the  grippers  meantime  hold- 
ing fiist  by  the  neck  of  the  pendant,  so  as  to  keep  the  plate  perfectly  steady  ;  the  dipping- 
finger  is  also  at  its  lowest  position,  and  resting  upon  the  knife-edge  at  the  bottom  of  the 
slot  in  the  pendant  rod,  thus  keeping  the  beam  horizontal,  and  the  knob  on  the  counter- 
poise pendant,  in  contact  with  the  agate  point  already  mentioned.  When  the  coin  is  fairly 
placed  on  the  weighing-plate,  the  grippers  let  go  their  hold  of  tlie  pendant  rod,  and  the 
dipping-finger  is  raised  by  its  cam  ;  if  then  the  coin  is  too  light,  tlie  coin  end  of  tlie  beam 
will  rise  along  with  the  dipping-finger,  and  the  counterpoise  end  will  descend  ;  if  lieavy, 
the  beam  will  remain  without  motion,  the  agate  point  preventing  it.  As  soon  as  the  dip- 
ping-finger attains  the  proper  height,  and  thus  has  allowed  sufiicient  time  for  the  weight  of 
the  coin  to  be  decided,  the  grippers  close  and  hold  the  pendant,  and  conse(|ueiit!y  the  scale 
-or  weighing-plate,  at  the  high  level,  if  the  coin  has  proved  light,  and  been  raised  by  the 
excess  of  weight  in  the  counterpoise ;  and  at  the  low  or  original  level,  if  the  coin  has 
proved  heavy.  One  of  the  displacing  slides  now  comes  forward  and  pa.sses  under  the  coin, 
if  it  is  light,  and  therefore  raised  to  the  high  level  ;  but  knocks  it  oft',  if  remaining  on  the 
low  level,  into  the  "  heavy  "  box.  The  other  disi)lacing  .slide  then  advances.  This  strikes 
higher  than  the  first,  and  removes  the  light  piece  which  the  other  has  missed,  into  the 
receptacle  for  the  light  coin.    During  these  operations  the  feeding-slide  has  brougni.  forward 


128  BALE. 

another  coin,  and  the  process  just  described  is  repeated.  The  attendant  is  only  required  to 
replenish  tlie  inclined  plane  at  intervals,  and  remove  the  assorted  coin  from  the  boxes.  The 
perfection  of  the  workmanship,  and  the  harmony  of  the  various  actions  of  the  machine, 
will  be  best  appreciated  from  the  fact,  that  25  pieces  are  weighed  per  minute  to  the  fineness 
of  ',100  of  a  grain.  This  combination  of  great  speed  and  accuracy  would  not  have  been 
possible  with  a  beam  made  in  the  ordinary  way,  having  the  centre  of  gravity  below  the 
centre  of  action  ;  and  it  w;is  pronounced  to  be  so  by  the  late  Mr.  Clement,  the  constructor 
of  Mr.  Babbage's  Calculating  Machine.  But  Mr.  Napier  overcame  the  difiiculty  by  raising 
the  centre  of  gravity  so  as  to  coincide  with  the  centre  of  action,  which  gave  it  much  greater 
sensibility ;  and  he  provided  the  dipping-finger,  to  bring  the  beam  to  a  horizontal  position 
after  each  weighing,  instead  of  an  influencing  weight  in  the  beam  itself. 

The  wear  and  tear  of  these  machines  are  found  to  be  very  small  indeed  ;  those  supplied 
in  1842  and  1843,  and  in  daily  use  ever  since,  weigh  with  the  same  accuracy  as  at  first, 
although  they  may  be  said  to  have  cost  nothing  for  repairs.  The  principal  cause  of  this 
long-continued  perfection  is  that  the  beam  does  not  oscillate,  unless  the  coin  is  light,  and 
even  then  ihe  space  passed  through  does  not  exceed  the  thickness  of  the  coin. 

In  1851,  when  the  Moneyers  were  no  longer  tuastcrs  o£  the  Royal  Mint,  and  the  new 
authorities  began  to  regard  the  process  of  weighing  the  coin  in  detail  by  hand  as  a  laborious, 
expensive,  and  inaccurate  method,  the  firm  of  Napier  &  Son,  at  an  interview  with  Sir  John 
Herschel,  the  Master,  and  Captain  Harness,  the  Deputy-Master,  received  an  order  for  five 
machines,  to  be  designed  to  suit  the  requirements  of  the  Mint,  which  involved  a  complete 
change  in  the  mechanical  arrangement  of  the  machine  as  used  at  the  Bank,  it  being  neces- 
sary to  divide  the  "  blanks,"  or  pieces  before  they  are  struck,  into  three  classes :  ''  too 
light,"  "  too  heavy,"  and  "  medium,"  or  those  varying  between  certain  given  limits.  It 
would  occupy  too  much  space  to  attempt  a  description  of  the  mechanical  disposition  of  this 
machine,  and  it  could  not  be  satisfactorily  accomplished  without  the  aid  of  drawings ;  let  it 
suffice,  then,  to  say  that  the  displacing-slides  are  removed,  and  a  long  vibrating  conducting- 
tube  receives  the  blanks  as  they  are  in  turn  pushed  off  the  weighing-plate  by  the  on-coming 
blanks ;  but,  according  to  the  weight  of  the  blank,  so  the  lower  end  of  the  tube  is  found  to 
be  opposite  to  one  of  three  openings  leading  into  three  boxes.  The  tube  is  sustained  in  its 
proper  position,  during  the  descent  of  the  blank  last  weighed  through  it,  by  a  stop-finger, 
tlie  height  of  which  is  regulated  by  a  dipping-finger,  which  comes  down  upon  a  knife-edge 
at  the  lower  end  of  a  slot  in  the  pendant-rod  just  when  the  grippcrs  have  laid  hold  of  the 
rod  after  the  weighing  is  finished  ;  this  finger  thus  ascertains  the  level  which  the  knife-edge 
has  attained,  and  as  it  brings  down  the  stop-finger  with  it,  the  guide-tube,  which  is  furnished 
with  three  rests,  as  steps  in  a  stair,  vibrates  against  the  stop-finger,  one  of  the  three  steps 
coming  in  contact  with  it,  according  to  the  level  of  the  stop-finger ;  and  the  end  of  the 
guide-tube  takes  its  place  opposite  the  channel  leading  to  the  box  in  which  the  blank  should 
be  found.  The  counterpoise  employed  is  less  than  the  true  standard  weight,  by  the  quan- 
tity which  may  be  allowed  as  the  limit  in  that  direction ;  and  in  case  a  blank  is  too  heavy, 
not  only  is  the  counterpoise  raised,  but  a  small  weight,  equal  to  the  range  allowed  between 
the  "  too  light "  and  "  too  heavy,"  is  raised  also  ;  this  small  weight  comes  to  rest  on  sup- 
ports provided  for  it  when  the  ijeam  is  horizontal,  and  is  only  disturbed  by  a  (oo  heavy 
blank. 

These  machines  have  proved  even  more  accurate  and  rapid  than  those  made  for  the 
Bank  ;  and  Professor  Graham,  the  present  master,  amongst  the  improvements  introduced 
by  him  into  the  system  of  the  Mint,  has  added  to  the  number,  and  dispensed  entirely  with 
the  hand-weighing.  It  is  said  that  the  saving  accruing  from  this  change  alone  amounts  to 
nearly  £2,000  per  annum. 

BALE.     A  package  of  silk,  linen,  or  woollen,  is  so  called. 

BALLISTIC  PENDULUM.  An  instrument  for  measuring  the  force  of  cannon-balls. 
The  ballista  was  an  instrument  used  by  the  ancients  to  throw  darts,  &c.  The  ballistic  pen- 
dulum derives  its  name  from  this :  it  consists  of  an  iron  cylinder,  closed  at  one  end,  sus- 
pended as  a  pendulum.  A  ball  being  fired  into  the  open  end,  deflects  the  pendulum  accord- 
ing to  the  force  of  the  blow  received  from  the  ball,  thus  measuring  its  power. 

BALLOON.  In  France,  a  quantity  of  glass.  Of  white  f/las.t,  25  bundles  of  six  plates 
each  ;  of  colored  glass,  12i  bundles  of  three  plates  each  are  called  balloons. 

BALLOON,  AIR.  A  varnished  silk  or  other  bag  filled  with  gas,  or  warm  air,  which, 
being  specifically  lighter  than  the  atmosphere,  ascends  in^t.  Numerous  attempts  have  been 
made  to  bring  air  balloons  under  the  control  of  the  aeronaut,  so  as  to  guide  them  across  the 
currents  of  the  atmosphere  ;  but  all  of  these  have  proved  unsuccessful,  the  balloon  and  its 
voyagers  having  always  moved  with  the  aerial  current,  in  spite  of  the  mechanical  appliances 
which  have  been  adopted. 

BAMBOO.  {Banibon,  Fr. ;  Indiavischer  Bohr,  Germ.)  A  species  of  cane,  the  Sam- 
bos nrnndinacea  of  botanists.  A  most  important  vegetable  product  in  the  East,  where  it  is 
used  in  the  construction  of  houses,  boats,  bridges,  &c.  Its  grain  is  used  for  bread  ;  its 
fibre  is  manufactured  into  paper. 


BARLEY. 


129 


Walking  sticks  are  frequently  said  to  be  of  bamboo ;  they  are  the  ratan,  a  different 
plant. 

BANDOLINE,  called  also  cli/xphitique  and  Jixalure,  a  mucilage  of  Carrageen  moss; 
used  for  stiffening  the  hair  and  keeping  it  in  order. 

BARBARY  GUM.  Sometimes  called  Morocco  fjiun.  The  product  of  the  Acacia 
gumiiiifera.     Imported  from  Tripoli,  Barbary,  and  Morocco. 

BARBERRY.  {Berberris,  Lat.  ;  Jipine-viuette,  Fr.)  It  is  probable  that  this  name  has 
been  given  to  this  plant  from  its  spines,  or  bai-bs.  The  name  Oxycaidhus,  also  given  to 
it,  indicates  a  like  origin. 

BARILLA.  {Sonde,  Barille,  Fr.  ;  Barilla,  Germ.)  A  crude  soda,  procured  by  the 
incineration  of  the  salsola  soda,  a  plant  cultivated  for  this  purpose  in  Spain,  Sicily,  Sar- 
dinia, and  the  Canary  Islands.  In  Alicante  the  plants  are  raised  from  seed,  which  is  sown 
at  the  close  of  the  year,  and  they  are  usually  fit  to  be  gathered  in  September  ibllowing.  In 
October  the  plants  are  usually  burned.  For  this  purpose  holes  are  made  in  the  earth,  capa- 
ble of  containing  a  ton  or  a  ton  and  a  half  of  soda.  Iron  bars  are  laid  across  these  cavi- 
ties, and  the  dried  plants,  stratified  with  dry  seeds,  are  placed  upon  them.  The  whole  is 
set  on  fire.  The  alkali  contained  in  the  plants  is  fused,  and  it  flows  into  the  cavity  beneath, 
a  red-hot  fluid.  By  constantly  heaping  on  plants,  the  burning  is  continued  until  the  pits  are 
full  of  barilla ;  they  are  then  covered  up  with  earth,  and  allowed  to  cool  gradually.  The 
spongy  mass  of  alkali,  when  sufficiently  cold,  is  broken  out,  and,  without  any  further  pre- 
paration, it  is  ready  for  shipment.  Good  barilla  usually  contains,  according  to  Dr.  Ure's 
analysis,  20  per  cent,  of  real  alkali,  associated  with  muriates  and  sulphates,  chiefly  of  s8da, 
some  lime,  and  alumina,  with  very  little  sulphur.  Caustic  leys  made  from  it  were  formerly 
used  in  the  finishing  process  of  the  hard  soap  manufacture. 

The  manufacture  of  barilla  has  greatly  declined  since  the  introduction  of  Le  Blanc's 
process  for  artificially  manufacturing  soda  from  common  salt. 

The  quantity  of  barilla  and  alkali  imported  in  1850  amounted  to  34,880  cwts.,  and  in 
1851  to  45,740  cwts.  ;  in  1856  the  importation  was  54,608  cwts. 

BARK.     The  outer  rind  of  plants.     Many  varieties  of  barks  are  known  to  commerce, 
but  the  term  is  especially  used  to  express  either  Peruvian  or  Jesuits'  bark,  a  pharmaceutical 
remedy,  or  Oak  bark,  which  is  very  extensively  used  by  tanners  and  dyers. 
The  varieties  known  in  commerce  are — 

Cork  Bark.     (Fr.  Liege  ;  Kork,  Germ.) 
Oak  Bark.     {Tan  brut,  Fr. ;  Eichenrinde,  Germ.) 
Peruvian  Bark.     {Quinquina,  Fr. ;   Chinarinde,  Germ.) 
Quercitron  Bark. 
Wattle  Bark. 
BARLEY.     {Orge,Yr.;    Gerstengraupe,  Germ. ;    Ilordemn,  Lmn.)     This  term  is  sup- 
posed to  be  derived  from  hordux,  heavy,  because  the  bread  made  from  it  is  very  heavy. 
Barley  belongs  to  the  class  JUndogens,  or  Monocotyledons ;    Glumel  Alliance,  of  Liiiley : 
natural  order,  Graminacece. 

There  are  four  species  of  barley  cultivated  in  this  country  : — 

1.  Hordeuni  hexastichon.     Six-rowed  barley. 

2.  Hordeum  vulgare.     The  Scotch  here  or  bigg  ;   the  four-rowed  barley. 

3.  Hordeum  zeocriton.     Putney,  fan,  sprat,  or  battledore  barley. 

4.  Hordeum  distichon.     Two-rowed  or  long-eared  barley. 

Barley  and  oats  are  the  cereals  whose  cultivation  extends  farthest  north  in  Europe. 

The  specific  gravity  of  English  barley  varies  from  1-25  to  1-33  ;  of  bigg  from  1-227  to 
1-265  ;  the  weight  of  the  husk  of  barley  is  %,  that  of  bigg  %.  Specific  gravity  of  barley 
is  1-235,  by  Dr.  Ure's  trials.  1,000  parts  of  barley  flour  contain,  according  to  Einhof,  720 
of^starch,  56  sugar,  50  mucilage,  36-6  gluten,  12-3  vegetable  albumen,  100  watci-,  2-5  phos- 
phate of  lime,  68  fibrous  or  ligneous  matter. 

From  the  examination  instituted  by  the  Royal  Agricultural  Society  of  England,  and  car- 
ried out  under  the  directions  of  Messrs.  Way  and  Ogston,  the  followhig  results  have  been 
arrived  at : — 


Kind  of  Barley  employed. 

Moisture  in 

100  Piirts  of 

Gr.iin. 

Specific 

Gravity  of 

Grains. 

Asli  in 
100  Parts  of 
(iric-d  Grain. 

Unknown        

Chevalier  barley 

Ditto 

Ditto,  from  Moldavia 

Ditto 

Grains  of  ChcvaUer  barley       .... 

12-00 
10-00 
16-00 
11-00 
10 -uO 
15-00 

1-200 
1-234 
1-268 

2-43 
2-50 
2-82 
2-38 
2-75 
14-23 

Vol.  III.— 9 


130 


BARREGE. 


The  analyses  o(  several  varieties  gave  as  the  composition  of  the  ashes  of  the  grains 
of  barley:— 


UnknowB. 

Chevalier 
Barley. 

From 
Moldavia. 

Chevalier 
Barley. 

Potash 

Soda 

Lime 

Magnesia     -         -         -         -         - 

Sesquisxide  of  iron 

Sulphuric  acid      -         -         -         - 

Silica 

Phosphoric  acid   -         -         -         - 
Chloride  of  sodium 

2114 

1-65 

7-26 
2-13 
1-91 
30-68 
28-53 
1-01 

20-77 
4-56 
1-48 
7-45 
0-51 
0-79 
32-73 
31-69 

37-55 
1-06 
1-21 

10-17 
1-02 
0-27 

24-56 

28-64 
1-47 

7-70 
0-36 

10-36 
1-26 
1-46 
2-99 

70-77 
1-99 
1-10 

In  the  "  Synopsis  of  the  Vegetable  Products  of  Scotland,"  by  Peter  Lawson  and  Son, 
will  be  found  the  best  description  of  all  the  different  varieties  of  barley ;  and,  since  the 
Lawsonian  collection  is  in  the  museum  of  the  Royal  Botanic  Gardens  at  Kew,  the  grains 
can  be  examined  readily  by  all  who  take  any  interest  in  the  subject.  A  few  only  of  the 
varieties  will  be  noticed. 

27/e  true  slx-roiocd  Barley,  known  also  as  Pomeranian  and  as  six-rowed  white  winter 
barley. — Thig  is  a  coarse  barley,  but  hardy  and  prolific.  It  is  occasionally  sown  in  France, 
and  also  in  this  country,  sometimes  as  a  winter  and  sometimes  as  a  spring  barley,  and  is 
found  to  answer  pretty  well  as  either. 

Naked  two-roived. — Ear  long,  containing  twenty-eight  or  thirty  very  large  grains,  which 
separate  from  the  palea;,  or  chaff,  in  the  manner  of  wheat.  This  variety  has  been  intro- 
duced to  the  notice  of  agriculturalists  at  various  times,  and  under  different  names,  but 
its  cultivation  has  never  been  carried  to  any  great  extent. 

Common  Bere,  Bigff,  or  roi>gh  Barley. — This  variety  is  chiefly  cultivated  in  the  High- 
lands of  Scotland,  and  in  the  Lowlands  on  exposed  inferior  soils. 

Victoria. — A  superior  variety  of  the  old  bigg,  compared  with  which  it  produces  longer 
straw,  and  is  long-eared,  often  containing  70  or  100  grains  in  each.  Instances  have  been 
known  of  its  yielding  13  quarters  per  acre,  and  weighing  as  much  as  96  lbs.  per  bushel. 

Beyond  these  there  are,  the  winter  black ;  the  vnnter  white  ;  old  Scottish  foiir-rotved ; 
naked,  r/oldcn,  or  Italian  ;  Suffolk  or  Norfolk,  and  Short-necked ;  cultivated  in  various  dis- 
tricts, and  with  varying  qualities. 

BARREGE.  a  woollen  fabric,  in  both  warp  and  woof,  which  takes  its  name  from  the 
district  in  which  it  was  first  manufactured — the  especial  locality  being  a  little  village  named 
Arosons,  in  the  beautiful  valley  of  Barreges.  It  was  first  employed  as  an  ornament  for  the 
head,  especially  for  sacred  ceremonies,  as  baptism  and  marriage.  Paris  subsequently  be- 
came celebrated  for  its  barreges,  but  these  were  generally  woven  with  a  warp  of  silk. 
Enormous  quantities  of  cheap  barreges  are  now  made  with  a  warp  of  cotton. 

BARREL.  {Baril,  Fr.)  A  round  vessel,  or  cask,  of  greater  length  than  breadth,  made 
of  staves,  and  hooped. 

The  English  barrel — wine  measure  contains  31^  gallons. 
"  (old)  beer"  "        36       " 

"  (old)  ale    "  "        32       " 

"  beer  vinegar  "        34       " 

"  contains  126  Paris  pints. 

The  ale  and  beer  barrels  were  equalized  to  34  gallons  by  a  statute  of  William  apd 
Mary.  The  wine  gallon,  by  a  statute  of  Anne,  was  declared  to  be  231  cubic  inches;  the 
beer  gallon  being  usually  reckoned  as  282  cubic  inches. 

Tiie  imperial  gallon  is  277-274  cubic  inches. 

The  old  barrels  now  in  use  are  as  follows  :— 
Wine  barrel  .         -         .         .         - 

Ale         "       (London)  .         -         .        - 
Beer      "  "        -        .        .        . 

Ale  and  beer,  for  England    .         -         - 

The  baril  de  Florence  is  equivalent  to  20  bottles. 

The  Connecticut  barrel  for  liquors  is  3H  gallons,  each  gallon  to  contain  231  cubic  inches. 

The  statute  barrel  of  America  must  be  from  28  to  31  gallons. 

The  barrel  of  flour.  New  York,  must  contain  either  195  lbs.  or  228  lbs.  net  weight. 

The  barrel  of  beef  or  pork  in  New  York  and  Connecticut  is  200  lbs. 

A  barrel  of  Essex  butter  is  106  lbs. 

A  barrel  of  Suffolk  butter  is  256  lbs. 

A  barrel  of  herrings  should  hold  1,000  fish.  • 

A  barrel  of  salmon  should  measure  42  gallons. 


26:1-  imperial  gallons. 

33='76» 
36=V5» 

34=v;, 


BAEWOOD. 


131 


BAROMETER.  A  name  given  to  one  of  the  most  important  instruments  of  meteo- 
rology. This  name  signifies  a  measurer  of  weight — the  column  of  mercury  in  the  tube  of 
the  barometer  being  exactly  balanced  against  the  weight  of  a  column  of  air  of  the  same 
diameter,  reaching  from  the  surface  of  tiie  earth  to  the  extreme  limits  of  the  atmosphere. 
The  length  of  this  column  of  mercury  is  never  more  than  thirty-one  inches ;  below  that 
point  it  may  vary,  according  to  conditions,  through  several  inches. 

There  have  been  many  useful  applications  of  the  barometer,  but  the  only  one  with  which 
this  dictionary  has  to  deal  appears  to  be  the  following : — 

Barometer,  MackwortlCx  Undcrciround. — In  the  goafs,  or  old  workings,  of  some  mines, 
hollows  exist,  in  which  explosive  or  noxious  gases  tend  to  accumulate  in  considerable  quan- 
tity. When  the  barometer  falls,  these  gases  expand  and  approach  or  enter  the  working 
places  of  the  mine,  producing  disastrous  results  to  life  or  health.  To  enable  the  manager 
of  a  mine  to  foresee  these  contingencies,  he  has  but  to  construct  a  small  model  of  such  a 
cavity,  and  let  the  expansion  or  contraction  of  the  gas  measure  itself.     In  Jiy.  49,  a  is  a 

49 


brass  vessel,  12  inches  long  and  1^  inches  in  diameter,  closed  at  each  end.  In  one  end  is 
inserted  a  copper  tube,  ^  inch  in  diameter  and  12  feet  long,  b.  A  hole,  2  inches  in  diam- 
eter, being  bored  12  feet  deep  into  the  solid  coal  or  rock,  the  brass  vessel  is  pushed  to  the 
bottom  of  it,  and  the  small  tube  is  closely  packed  round  with  coal  or  clay,  c  is  a  glass 
tube,  4  feet  long  and  \  inch  in  diameter,  in  which  is  placed  water  or  oil.  As  the  external 
atmosphere  presses,  the  surface  of  the  liquid  rises  or  falls,  and  the  scale  is  graduated  by 
comparison  with  a  standard  barometer.  The  air  contained  in  the  brass  vessel  a,  and  copper 
tube  B,  is  unaffected,  or^early  so,  by  temperature,  and  no  correction  has  to  be  made  for  the 
latter  as  in  the  sympiesometer.  a  and  b  may  be  conveniently  filled  with  nitrogen,  to  pre- 
vent the  oxidation  of  the  metal ;  and  the  surface  of  the  liquid  in  the  glass  tube  may  be 
made  self-registering,  either  giving  maxima  and  minima,  or,  by  the  addition  of  clock-work, 
taking  diagrams  on  paper. 

BARWOOD.  Although  distinctions  are  made  between  sandal  or  saunders  wood,  cam- 
wood, and  barwood,  they  appear  to  be  very  nearly  allied  to  each  other — at  least,  the  color- 
ing matter  is  of  the  same  composition.     They  come,  however,  from  different  places. 

MM.  Girardin  and  Preisser  thus  describe  this  wood  : — 

This  wood,  in  the  state  of  a  coarse  powder,  is  of  a  bright-red  color,  without  any  odor  or 
smell.     It  imparts  scarcely  any  color  to  the  saliva. 

Cold  water,  in  contact  with  this  powder,  only  acquires  a  f;\wn  tint  after  five  days'  macer- 
ation. 100  parts  of  water  only  dissolve  2-21  of  substances  consisting  of  0-85  coloring 
matter  and  of  1-36  saline  compounds.  Boiling  water  becomes  more  strongly  colored  of  a 
reddish  yellow ;  but,  on  cooling,  it  deposits  a  part  of  the  coloring  principle  in  the  form  of 
a  red  powder.  100  parts  of  water  at  212"  dissolve  8-86  of  substances  consisting  of  7-24 
coloring  principle,  and  1-62  salts,  especially  sulphates  and  chlorides.  On  macerating  tlic 
powder  in  strong  alcohol,  the  liquid  almost  immediately  acquires  a  very  dark  vinous  red 
color.  To  remove  the  whole  of  the  color  from  fifteen  grains  of  this  powder,  it  was  neces- 
sary to  treat  it  several  times  with  boiling  alcohol.  The  alcoholic  li(iuid  contained  O'To  of 
coloring  principle  and  0-004  of  salt.  Barwood  contains,  therefore,  23  per  cent,  of  red 
coloring.matter ;  whilst  saunders  wood,  according  to  Pelletier,  only  contains  lG-75. 

The  alcoholic  solution  behaves  in  the  following  manner  towards  re-agents  : — 
Distilled  water  added  in  great  quantity  -    Produces  a  considerable  yellow  opalescence.   The 

precipitate  is  re-dissolved  by  the  fixed  alkalies, 
and  the  liquor  acquires  a  dark  vinous  color. 

Fixed  alkalies Turn  it  dark  crimson,  or  dark  violet. 

Lime  water Ditto. 

Sulphuric  acid Darkens  the  color  to  a  cochineal  red. 


132  BAKYTA,  CARBONATE  OF. 

Sulphuretted  hydrogen  -         -         -         -  Acts  like  water. 

Salt  of  tin     -  " Blood-red  precipitate. 

Chloride  of  tin Brick-red  precipitate. 

Acetate  of  lead Dark  violet  gelatinous  precipitate. 

Salts  of  the  protoxide  of  iron         -         -  Very  abundant  violet  precipitates. 

Copper  salts Violct-bro^vn  gelatinous  precipitates. 

Ciiloride  of  mercury      .         .         -         -  An  abundant  precipitate  of  a  brick-red  color. 

Nitrate  of  bismuth         .         .         -         .  Gives  a  light  and  brilliant  crimson  red. 

Sulphate  of  zinc Bright-red  flocculent  precipitate. 

Tartar  emetic         -         -         -         -         -  An  abundant  precipitate  of  a  dark  cherry  color. 

Neutral  salts  of  potash  -         -         -         -  Acts  like  pure  water. 

Water  of  barytes  -         -         -.       -         -  Dark  violet-brown  precipitate. 

Gelatine Brownish-yellow  ochrous  precipitate. 

Chlorine Brings  back  the  liquor  to  a  light  yellow,  with  a 

slight  yellowish-brown  precipitate,  resembling 
bydrated  peroxide  of  iron. 

Pyroxylic  spirit  acts  on  barwood  like  alcohol,  and  the  strongly  colored  solution  behaves 
similarly  towards  re-agents.  Hydrated  ether  almost  immediately  acquires  an  orange-red 
tint,  rather  paler  than  that  with  alcohol.  It  dissolves  19-4'7  per  cent,  coloring  principle. 
Ammonia,  potash,  and  soda,  in  contact  with  powdered  barwood,  assume  an  extremely  dark 
violet-red  color.  These  solutions,  neutralized  with  hydrochloric  acid,  dej)osit  the  coloring 
matter  in  the  form  of  a  dark  reddish-brown  powder.  Acetic  acid  becomes  of  a  dark-red 
color,  as  with  saunders  wood. 

Barwood  is  but  slightly  soluble ;  but  the  difficulty  arising  from  its  slight  solubihty  is, 
according  to  Mr.  Napier,  overcome  by  the  following  very  ingenious  arrangement : — The 
coloring  matter  while  hot  combines  easily  with  the  proto-compounds  of  tin,  forming  an 
insoluble  rich  red  color.  The  goods  to  be  dyed  are  impregnated  with  proto-chloride  of  tin 
combined  with  sumach.  The  proper  proportion  of  barwood  for  the  color  wanted  is  put  into 
a  boiler  with  water,  and  brought  to  boil.  The  goods  thus  impregnated  arc  put  into  this 
boiling  water  containing  the  rasped  wood,  and  the  small  portion  of  coloring  matter  dissolved 
in  the  water  is  inmiediately  taken  up  by  the  goods.  The  water,  thus  exhausted,  dissolves  a 
new  portion  of  coloring  matter,  which  is  again  taken  up  by  the  goods,  and  so  on  till  the  tin 
upon  the  cloth  has  become  (if  we  may  so  term  it)  satm-ated.  The  color  is  then  at  its  bright- 
est and  richest  phase. 

In  1855,  the  quantity  of  barwood  imported,  duty  free,  was  2,710  tons. 

Of  the  barwood  imported,  227  tons  were  re-exported;  the  computed  real  value  of  which 
was  £1,241. 

BARYTA,  CARBONATE  OF.  The  composition  of  the  native  carbonate  of  baryta 
may  be  regarded  as  baryta  77'59  and  carbonic  acid  22-41.  It  is  fo^d  in  Shropshire,  Cum- 
berland, Westmoreland,  and  NorthumVjcrland.  The  carbonate  of  baryta  is  employed  in  our 
coh^r  manufactories  as  a  biise  for  some  of  the  more  delicate  colors;  it  is  also  used  in  the 
manufacture  of  plate-glass  ;  and,  in  France,  it  is  much  used  in  the  preparation  of  beet-root 
sugar. 

Tons.     cwts. 

Alston  Moor  produced,  in  1856 443       10 

Fallowfield  (Northumlxrland)  ditto 1,045       18 

BARYTA,  SULFHATE  OF.  The  baryte  of  Brooke  and  Miller,  barytes  of  Dana  and 
Phillips,  Bolognian  spar,  called  also  "  cawk  "  and  "  heavy  spar."  It  is  composed  of  baryta 
05-63,  sulphuric  acid  34-37,  with  sometimes  a  little  iron,  lime,  or  silica. 

This  salt  of  baryta  is  very  extensively  spread  over  various  parts  of  the  islands.  It  is 
worked  largely  in  Derbyshire,  Yorkshire,  Shropshire,  and  the  Isle  of  Arran.     In  1856  the 

production  was  as  follows  : — From 

Tons. 

Derbvshire 8,000 

Shropshire ■ 1,200 

Bantry  (Ireland) 700 

Isle  of  Arran 550 

Kirkcudbright 70 

It  might  be  obtained  in  very  large  quantities  in  Devonshire,  Cornwall,  and  other  places, 
if  the  demand  for  it  .sufficiently  increased  the  price  so  as  to  render  the  working  of  it  profit- 
able. A  large  quantity  of  the  ground  sulphate  of  baryta  is  employed  in  the  adulteration 
of  white  lead.  Paint  containing  much  barytes  very  soon  wa.«hes  off  the  surface  upon  which 
it  is  spread.  Lead  combines  with  the  oil,  and  forms,  indeed,  a  plaster.  No  such  combina- 
tion takes  place  between  the  oil  and  the  baryta,  hence  they  soon  separate  by  the  action  of 
water.  Baryta  is  employed  to  some  extent  in  the  pyrotechnic  art,  in  the  production  of 
flames  of  a  grecnisli  character. 


BATHS. 


133 


In  1856  we  imported — 

Tone. 
Baryta,  sulphate  (ground)  --.•-.  --    494 

And  in  the  same  year  we  exported — 

Cwts.  Declared  Value. 

Barytes  (sulphate  and  carbonate)       -         -         -     67,751      -         -      £12,145 

BASALT.  One  of  the  most  common  varieties  of  trap  rock.  It  is  a  dark  green  or 
black  stone,  composed  of  augite  and  felspar,  very  compact  in  texture,  and  of  considerable 
hardness  often  found  in  regular  pillars  of  three  or  more  sides,  called  "  basaltic  columns." 
Remarkable  examples  of  this  kind  are  seen  at  the  Giant's  Causeway,  in  Ireland,  and  at  Fin- 
"al's  Cave,  in  Staffa,  one  of  the  Hebrides.  The  term  is  used  by  Pliny,  and  is  said  to  come 
from  basal,  an  Ethiopian  word  signifying  iron.  The  rock  sometimes  contains  much  iron. — 
LyeWs  Principles  of  Geolorpj.  Experiments  have  been  made  on  a  large  scale  to  apply 
basaltic  rock,  after  it  has  undergone  fusion,  to  decorative  and  ornamental  purposes.  Messrs. 
Chance  (brothers)  of  Birmingham,  have  adopted  the  process  of  melting  the  Rowley  rag,  a 
basaltic  rock  forming  the  plateau  of  the  Rowley  hills,  near  Dudley,  South  Staffordshire,  and 
then  casting  it  into  moulds  for  architectural  ornaments,  tiles  for  pavements,  &c.  Not  only 
the  Rowley  rag,  but  basalt,  green.stone,  whinstone,  or  any  similar  mineral,  may  be  used. 
The  material  is  melted  in  a  reverberatory  furnace,  and  when  in  a  sufficiently  fluid  state  is 
poured  into  moulds  of  sand  encased  in  iron  boxes,  these  moulds  having  been  previously 
raised  to  a  red  heat  in  ovens  suitable  for  the  purpose.  The  object  to  be  attained  by  heating 
the  moulds  previous  to  their  reception  of  the  liquid  material,  is  to  retard  the  rate  of  cool- 
ing ;  as  the  result  of  slow  cooling  is  a  hard,  strong,  and  stony  substance,  closely  resembling 
the  natural  stone,  while  the  result  of  rapid  cooling  is  a  dark  brittle  glass. 

BASILICOX.  The  name  given  by  the  old  apothecaries  to  a  mixture  of  oil,  wax,  and 
resin,  which  is  represented  by  the  Cerat.  resince  of  the  present  day. 

BASSORA  GUM.  A  gum  obtained  from  the  Acacia  lencopklcea,  brought  from  Bas- 
sora.     It  has  a  specific  gravity  of  1-3591,  and  is  yellowish  white  in  color. 

BASKETS.  Weaving  of  rods  into  baskets  is  one  of  the  most  ancient  of  the  arts 
amongst  men  ;  and  it  is  practised  in  almost  every  part  of  the  globe,  whether  inhabited  by 
civilized  or  savage  races. 

Basket-making  requires  no  description  here. 

Importations  : — 

In  1856  we  imported  of  rods  peeled  for  basket-making,  123,103  bundles,  value  £12,309 
"  rods  unpeeled  "  157,146       "  "  7,858 

"  "  baskets,      -         -         -         -      176,730  cubic  feet,  "         37,580 

Of  these,  152,777  cubic  feet  were  from  France. 

BATH  METAL  consists  of  3  oz.  of  zinc  to  1  lb.  of  copper. 

BATHS.  Public  baths  and  wash-houses  have  now  become  common  amongst  us,  and  with 
them  an  increased  cleanliness  is  apparent,  and  improved  health  throughout  the  population. 

The  following  is  a  return  of  the  bathing  and  washing  at  the  public  baths  and  wash-houses 
in  London,  conducted  under  or  in  accordance  with  the  Acts  9  and  10  Yict.,  cap.  74,  and  10 
and  11  Vict.,  cap.  61,  and  of  a  few  out  of  the  similar  establishments  in  the  country  : — 


Name  of  Establishment. 

Number  of 
Bathers. 

Number  of 
Washers. 

Total 
Kcceipts. 

JfetropoUn. 

1.  The  Model,  Whitcchapcl     - 

2.  St.  Martin's-in-the-Fields     - 

3.  St.  Marylebone 

4.  St.  Margaret  and  St.  John,  Westminster 

5.  Greenwich 

6.  St.  James,  Westminster      ... 

7.  Poplar 

8.  St.  Giles's  and  Bloomsbury 

Totals 

156,110 

155,418 

155,827 

111,392 

61,782 

111,870 

41,490 

8.3,810 

42,589 
46,337 
37,061 
66,644 
8,815 
35,829 
10,714 
21,051 

£  «  d. 
2,976  7  8 
3,007  5  10 
2,498  2  3 
2,204  12     5 

995  11  4 
2,038  10  11 

845  15  10 
1,546     3     0 

877,099 

209,040     j  16,112     9     8 

Country. 
Liverpool : — 

Connvallis  Street         .... 

Paul  Street 

George's  Pier-head       ,         .         -         . 

Hull 

Bristol    .--.--- 
Preston  -•--..- 
Birmingham    --.--. 
Maidstone 

98,460 
44,747 
45,243 
52,142 
40,262 
29,296 
98,396 
31,221 

11,480 

7,579 

11,068 

10,376 

5,547 

6,773 

I 
i 

1,561     3     2 
797     4     4" 

1,084     5     6 
612     8     7 
599  n     2 
405  10     5 

1,8.54   14     5 
318     8  10 

134 


BAY  SALT. 


The  return  does  not  indiide  the  George  Street  (Hampstead  Koad)  and  Lambeth  estab- 
lishments, which  are  not  regulated  by  the  public  acts. 

The  steady  increase  of  the  revenue  derived  from  the  baths  and  wash-houses  in  London 
from  the  commencement  of  the  undertaking  in  1846,  shows  the  practical  utility  of  these 
institutions,  aud  their  efl'ect  on  the  physical  and  social  condition  of  the  industrious  classes  ; 
viz.  : — 

The  aggregate  receipts  of  nine  establishments,  inclusive  of  the 
George  Street  establishment,  during  1853,  amount  to 

1852.  Eight  establishments 

Six  establishments 

Four  establishments    -..-... 
Three  establishments  ------- 


1851. 
1850. 
1849. 

1848. 
1847. 


Two  establishments 2,896 

I 


-  Ditto 


£       s. 

d. 

18,213    5 

8 

15,629    5 

8 

12,906  12 

5 

9,823  10 

6 

6,379  17 

2 

2,896    5 

1 

3,222    1 

5 

1846.  ) 

Showing  an  increase,  in  1853  over  1846,  of  £15,317  Os.  7f7. 

Those  conveniences — now,  indeed,  become  absolute  necessities — are  extending  in  every 
part  of  the  country. 

Baths,  as  curative  agents,  are  of  very  different  kinds.  Yapor  Baths  are  stimulant  and 
sudorific  ;  they  may  be  either  to  be  breathed,  or  not  to  be  breathed.  Dr.  Pereira  has  given 
the  following  Table,  as  a  comparative  view  of  the  heating  powers  of  vapor  and  of  water  : — 


Kind  of  Bath. 

Water. 

Vapor. 

Not  breathed. 

Breathed.          | 

Tepid  bath          .         .         -         . 
Warm  bath         ...         - 
Hot  bath 

85'  to     92° 
92     "      98 
98     "    106 

96°  to  106° 
106     "    120 
120     "    160, 

90°  to  100° 
100      "    110 
110     "    130 

Local  vapor  baths  are  applied  in  affections  of  the  joints,  and  the  like. 

Vapor  douche  is  a  jet  of  aqueous  vapor  directed  on  some  part  of  the  body. 

Medicated  vapor  baths  are  prepared  by  impregnating  vapor  with  the  odors  of  medicinal 
plants. 

Sulphur,  chlorine,  sulphurous  acid,  iodine,  and  camphor,  are  occasionally  employed  in 
conjunction  with  aqueous  vapor. 

ITrtDH,  tepid,  and  hot  baths  are  suflSciently  described  above. 

BAY  SALT.     The  larger  crystalline  salt  of  commerce. 

BAY,  THE  SWEET.  (Laurvs  twbilis.)  Bay  leaves  have  a  bitter  aromatic  taste,  and 
an  aromatic  odor,  which  leads  to  their  use  in  cookery. 

BAYS,  OIL  OF.  This  oil  is  imported  in  barrels  from  Trieste.  It  is  obtained  from  the 
fresh  and  ripe  berries  of  the  bay  tree  by  bruising  them  in  a  mortar,  boiling  them  for  three 
hours  in  water,  and  then  pressing  them.  When  cold,  the  expressed  oil  is  found  floating  on 
the  top  of  the  decoction.  Its  principal  use  is  in  the  preparation  of  veterinary  embroca- 
tions. 

BEADS.  {Grain,  Fr.  ;  Bethe,  Germ.)  Perforated  balls  of  glass,  porcelain,  or  gems, 
strung  and  worn  for  ornaments ;  or,  amongst  some  of  the  uncivilized  races,  employed 
instead  of  money. 

Gla&s  beads  have  long  been  made  in  very  large  quantities  in  the  glass-houses  of  Murano, 
at  Yenicc. 

Glass  tubes,  previously  ornamented  by  color  and  reticulation,  are  drawn  out  in  proper 
sizes,  from  100  to  200  feet  in  length,  and  of  all  possible  colors.  Not  less  than  200  shades 
are  manufactured  at  Venice.  These  tubes  are  cut  into  lengths  of  about  ^two  feet,  and  then, 
with  a  knife,  they  are  cut  into  fragments,  having  about  tlie  same  length  as  their  diameter. 
The  edges  of  these  beadj  are,  of  course,  sharp ;  and  they  are  subjected  to  a  process  for 
removing  this.  Sand  and  wood-ashes  are  stirred  with  the  beads,  so  that  the  perforations 
may  be  filled  by  the  sand  ;  this  prevents  the  pieces  of  glass  from  adhering  in  the  subse- 
quent process,  which  consists  in  putting  them  into  a  revolving  cylinder  and  heating  them. 
The  finished  beads  are  sifted,  sorted'in  various  sizes,  and  strung  by  women  for  the  market. 
•  In  the  Jurors'  Report  of  the  Great  Exhibition  of  1851  are  the  following  remarks  on  this 
mamifacture  :  — 

"  The  old  Venetian  manufactures  of  glass  and  glass  wares  fully  sustain  their  importance ; 
and  those  of  paper,  jewellery,  wax-lights,  Tclvets,  and  laces,  rather  exceed  their  ordinary 
production.  The  one  article  of  beads  employs  upwards  of  5,000  people  at  the  principal 
fabric  on  the  island  of  Murano  ;    and  the  annual  value  is  :  t  least  £200,000.      They  are  ex- 


BEN  OIL.  135 

ported  to  London,  Marseilles,  Hamburg,  and  thence  to  Africa  and  Asia,  and  the  great  East- 
ei'n  Archipelago." 

The  perles  a  la  lime  are  a  finer,  and,  consequently,  more  expensive  bead,  which  are 
prepared  by  twisting  a  small  rod  of  glass,  softened  by  a  blowpipe,  about  an  iron  wire. 

The  preparation  and  cutting  of  gems  into  beads  belong  especially  to  the  lapidary.  The 
production  of  beads  of  Paste,  and  of  artificial  Pearls,  will  be  noticed  under  those  heads 
respectively. 

In  India  beads  of  rock  crystal  are  often  very  beautifully  cut. 

Dr.  Gilchrist  states : — Coral  beads  are  in  high  estimation  throughout  Hindostan  for 
necklaces  and  bracelets  for  women.  These  beads  are  manufactured  from  the  red  coral 
fished  up  in  various  parts  of  Asia ;  they  are  very  costly,  especially  when  they  run  to  any 
size  ;  and  they  are  generally  sold  by  their  weight  of  silver. 

Coral  beads  were  always  favorite  articles  for  ornament  even  in  this  country  ;  and  in  the 
"  Illustrations  of  Manners  and  Expences  of  antient  Times  in  England,"  by  Nicholls,  1798, 
we  find  the  following  entries  from  "  the  churchwardens'  accompts  of  St.  Mary  Hill,  London," 
containing  "  the  inventory  of  John  Port,  layt  the  king's  servant,  as  after  followeth  :" — 
"  Item  of  other  old  gear  found  in  the  house  : —    -        -        -        -    £    s.   d. 

"  Item  otie  oz.  and  ^  of  corall 026 

"  Jewels  for  her  body. 

"  Item,  a  pair  of  coral  beds,  gaudyed  with  gaudys  of  silver  and  gilt, 

10  oz.  at  3s.  4J. 1  13    4." 

(John  Port  died  in  1524.) 

We  imported,  in  1856,  of  coral  beads,  2,279  lbs.,  and  of  jet  beads,  9  lbs. ;  while  of 
other  kinds  uuenumerated,  14,281  lbs.  were  brought  into  the  United  Kingdom. 

In  addition  to  those,  the  followbg  were  our  Imports  of  glass  beads  and  bugles : — 

Computed  real  value, 
lbs.  £ 

Denmark 8,889  -         -         -  1,111 

Hanse  Towns 541,580  -         -         -  67,697 

Holland 37,446  -         -         -  4,681 

Belgium 25,704  -         -         -  3,213 

France 6,835  ...  854 

Sardinia 18,949  ...  947 

Tuscany 10,432  ...  522 

Austrian  Italy       ....  1,493,452  -         -         -  74,673 

Other  parts 14,306  -         -         -  1,564 

2,157,593  £155,262 

We  exported,  in  1856,  ornamental  beads  to  the  value  of  £21,504. 

BEAVER,  THE.  {Castor  Fiber.)  This  animal  is  caf>tured  for  its  skin,  and  for  the 
castor,  {castorewn,)  which  is  employed  medicinally.     See  Furs. 

BEBIRINE,  or  BEBEERINE.  (C'^H^'NO".)  An  alkali  discovered  by  Dr.  Rodie,  of 
Demerara,  in  the  bark  of  the  bebeern  tree.  It  was  examined  more  minutely  by  Madagan 
and  Tilley,  and  still  more  recently  by  Von  Planta,  who  has  determined  its  true  formula.  It 
is  very  bitter,  and  highly  febrifuge. 

BEECH.  {Hi'trc  commim,  Fr. ;  Gemeine  Buclie,  Germ.)  The  beech  tree  (the  Fagiis 
silvatica  of  Linnasus)  is  one  of  the  most  magnificent  of  the  English  trees,  attaining,  in  about 
sixty  or  seventy  years  in  favorable  .situations,  a  height  of  from  70  to  100  feet,  and  its  trunk 
a  diameter  of  five  feet.  The  wood,  when  green,  is  the  hardest  of  British  timbers,  and  its 
durability  is  increased  by  steeping  in  water  ;  it  is  chiefly  used  by  cabinet-makers,  coopers, 
coach-builders,  and  turners.  A  substitute  for  olive  oil  has  been  extracted  from  beech  nuts. 
BELLADOXNA.  {Belledame,  Fr.)  The  Atropa  Bclladomia,  or  deadly  nightshade. 
BELL-METAL  ORE.  Sulphide  of  Tin.  {Etain  sulphure,  Haiiy ;  Zinnkics,  Ilaus- 
mann.) 

The  composition  of  the  ordinary  variety  of  this  ore  is, 

Copper 30-0 

Iron 120 

Tin 26-5 

Sulphur 30-5 

%  99-0 

It  is  found  in  many  of  the  Cornish  mines,  and  especially  at  those  of  Cam  Brea. 

BEN  NUTS.  {Ben  nnix,  Vr.  ;  Satbriusae,  (icTij\.)  The  tree  which  furnishes  these  nuts 
is  the  Guilandina  inoriuf/n  of  Linnaeus,  a  native  of  India,  Ceylon,  Arabia,  «md  Egy])t. 

BEN  OIL.  The  oil  of  ben,  which  may  be  obtained  from  the  decorticated  nuts,  is  said 
to  be  far  less  liable  than  other  oils  to  become  rancid,  and  hence  it  is  much  used  by  watch- 


136  BENZOIC  ACID. 

makers.  At  a  low  temperature,  the  oil  of  ben  separates  into  two  parts — one  solid  and  one 
fluid  ;  the  latter  only  is  used  for  watch-work.  On  account  of  its  freedom  from  rancidity, 
oil  of  ben  is  used  by  Parisian  perfumers  to  form  the  basis  of  the  Indies  antiques  of  tube- 
rose, jasmin,  &c.     See  Oils. 

BENZOIC  ACID.  (CU^Ol)  This  acid  may  be  obtained  by  placing  benzoin  powdered 
with  sand  in  an  evaporating  basin,  and  above  it  a  paper  cap  ;  on  applying  heat  carefully  to 
the  sand,  acid  vapors  arise  from  the  resin,  and  they  are  deposited  in  the  form  of  fine  light 
crystals  with  the  paper  cap.  Stolze  recommends  the  following  process  for  extracting  the 
acid  : — The  resin  is  to  be  dissolved  in  three  parts  of  alcohol,  the  solution  is  to  l^e  introduced 
into  a  retort,  and  a  solution  of  carbonate  of  soda  dissolved  in  dilute  alcohol  is  to  be  gradu- 
ally added  to  it,  till  the  free  acid  be  neutralized  ;  and  then  a  bulk  of  water  equal  to  double 
the  weight  of  the  benzoin  is  to  be  poured  in.  The  alcohol  being  drawn  off"  by  distillation 
the  remaining  liijuor  contains  the  acid,  and  the  resin  floating  upon  it  may  be  skimmed  off 
and  wa.shed,  when  its  weight  will  be  found  to  amount  to  about  8(1  per  cent,  of  the  raw  ma- 
terial. The  benzoin  contains  traces  of  a  volatile  oil,  and  a  substance  soluble  in  water,  at 
least  through  the  agency  of  carbonate  of  potash.  There  are  several  other  methods  for 
obtaining  benzoic  acid,  described  in  L'rc's  "Dictionary  of  Chemistry."  Benzoic  acid  has  no 
special  use  in  the  arts. 

BENZOLE.  Siin.  Benzine,  benzene,  benzol,  hydruret  of  phcnyle,  (C'-IP.)  The  more 
volatile  portion  of  coal  naphtha  has  been  shown  by  Mansfield  to  consist  chiefly  of  this  sub- 
stance. It  is  produced  in  a  great  number  of  reactions  in  which  orgimic  bodies  are  exposed 
to  high  temperatures.  It  may  at  once  be  obtained  in  a  state  of  purity  by  distilling  benzoic 
acid  with  excess  of  quicklime.  The  lime  acts  by  removing  two  equivalents  of  carbonic  acid 
from  the  benzoic  acid.  The  method  of  obtaining  benzole  from  coal  naphtha  will  be  found 
fully  described  under  the  head  of  Naphtha  Coal.  Benzole  is  also  contained  in  consider- 
able  quantity  in  bone  oil ;  but  it  is  accompanied  by  peculiar  nitrogenized  volatile  fluids, 
which  arc  difficult  of  removal.  The  latter,  owing  to  their  powerful  and  fetid  odor,  greatly 
injure  the  (juality  of  the  bone-oil  benzole.  Benzole  is  an  exceedingly  volatile  fluid,  boiling 
at  ordinary  pressures  at  187"  F.  Its  density  is  0-850.  Owing  to  the  levity  of  benzole 
being  regarded  by  manufacturers  as  a  proof  of  its  purity,  it  is  not  uncommon  to  find  it 
adulterated  with  the  naphtha  from  the  Toibanehill  mineral,  or  Boghead  coal,  which  has  a 
density  as  low  as  0'750.  Any  benzole  having  a  lower  density  than  0-850  is  impure.  Ben- 
zole is  excessively  inflammable,  and  its  vapor  mixed  with  air  is  explosive.  Numerous  lives 
have  been  lost  owing  to  these  properties,  among  them  that  of  Mr.  Mansfield,  to  ■whom  we 
are  indebted  for  an  excellent  investigation  on  coal  naphtha.  Benzole  is  greatly  used  in 
commerce,  owing  to  its  valuable  solvent  properties.  It  dissolves  caoutchouc  and  gutta  jiercha 
readily,  and,  on  evaporation,  leaves  them  in  a  state  well  adapted  for  water-proofing  and  many 
other  purposes.  Its  power  of  dissolving  fatty,  oily,  and  other  greasy  matters,  has  caused  it 
to  become  an  article  of  commerce  under  the  name  of  benzoline.  It  readily  extracts  grease 
even  from  the  most  delicate  fabrics,  and,  as  it  soon,  on  exposure  to  the  air,  evaporates 
totally  away,  no  odor  rem.ains  to  betray  the  fact  of  its  having  been  used.  It  dissolves 
readily  in  very  strong  nitric  acid,  and,  on  the  addition  of  water,  it  is  precipitated  as  a  heavy 
oil,  having  the  composition  C'^ir'NO^  The  latter  compound  is  nitrobenzole  ;  it  is  regarded 
as  benzole  in  which  one  cfiuivalent  of  hydrogen  is  replaced  by  liyponitric  acid.  Nitroben- 
zole, in  a  state  of  tolerable  purity,  is  a  pale-yellow  oil,  having  a  sweetish  taste,  and  an  odor 
gi'catly  resembling  bitter  almonds.  Owing  to  its  comparative  cheapness,  it  is  employed  in 
perfumery.  Nitrobenzole  can  be  prepared  with  nitric  acid  of  moderate  strength,  such  as  is 
ordinarily  obtained  in  commerce  ;  but  it  then  becomes  necessary  to  distil  the  acid  and  the 
hydrocarbon  together  several  times.  The  product  so  obtained  is  darker  in  color,  and  in 
other  respects  inferior  to  that  obtained  with  highly  concentrated  acid.  By  treatment  with 
acetate  of  protoxide  of  iron,  nitrobenzole  becomes  transformed  into  aniline.  This  change 
may  be  eflFectcd,  but  far  less  conveniently,  by  means  of  sulphide  of  ammonium.  Benzole 
is  extremely  valualile  in  many  operations  of  manufacturing  chemistry.  It  dissolves  several 
alkaloids,  and,  on  evaporation,  leaves  them  in  a  state  of  purity.  It  dissolves  quinine,  but 
not  cinchonine,  and  may  therefore  be  employed  as  a  means  of  separation.  Morphia  and 
strychnine  are  also  dissolved  by  it,  but  not  in  great  quantity.  To  obtain  many  natural  alka- 
loids existing  in  plants,  it  is  merely  necessary  to  digest  the  dry  extract  with  caustic  potash 
and  then  witli  benzole.  The  latter  is  to  be  decanted,  and  then  distilled  off"  on  a  water-bath. 
The  alkaloid  will  be  left  behind  in  a  state  well  adapted  for  crystallization  or  other  means  of 
purification.  Benzole  is  becoming  much  used  a.s  a  solvent  in  researches  in  organic  chemis- 
try. Many  substances,  such  as  chrysenc  and  bichloride  of  naphthaline,  crystallize  better 
from  benzole  than  from  any  other  solvent.  # 

Benzole  may  be  employed  in  many  ways  for  illuminating  purposes.  It  is  so  easily  in- 
flamed that  great  care  is  necessary  in  using  it.  It  docs  not  require  a  wick  to  enable  it  to 
burn.  If  poured  even  on  an  uninflammable  surface  and  a  light  be  applied,  it  takes  fire  like 
a  train  of  gunpowder,  and  burns  with  a  brilliant  flame,  emitting  dense  clouds  of  smoke, 
which,  soon  condensing  into  soot,  presently  fall  in  a  shower  of  blacks.     Even  on  the  sur- 


BERTHOLLETIA. 


137 


face  of  water  it  burns  as  freely  as  anywhere  else.  If  a  drachm  or  two  be  poured  on  water 
contained  in  a  pan,  and  a  pellet  of  potassium  be  thrown  in,  the  benzole  inflames,  and  rises 
in  a  column  of  flame  of  considerable  height.  A  method  of  destroying  enemies'  shipping  has 
been  founded  on  this  principle.  In  consequence  of  the  smohy  nature  of  the  flame  of  ben- 
zole, (caused  l.)y  the  comparatively  larger  perc-entage  of  carbon,)  it  is  often  convenient  to 
burn  a  mixture  of  one  volume  of  benzole  and  two  volumes  of  iricohol.  A  stream  of  air 
driven  through  benzole  becomes  so  inflammable  as  to  serve  for  the  purposes  of  illumination. 
For  this  mode  of  using  the  hydrocarbon,  it  should  be  kept  slightly  warm  to  assist  its  vapor- 
ization. A  machine  on  this  principle,  of  American  invention,  has  been  employed  to  illumi- 
nate houses.  The  air  is  driven  through  the  benzole  by  a  very  simple  contrivance,  the 
motive  power  being  a  descending  weight. 

When  quite  pure,  benzole  freezes  at  32°  to  a  beautiful  snow-white  substance,  resembling 
camphor.  The  mass  retains  a  solid  form  until  a  temperature  of  40^  or  41"  is  reached. 
This  property  of  solidifying  under  the  influence  of  cold  may  be  made  use  of  to  produce 
pure  benzoic  from  the  more  volatile  portion  of  coal  naphtha.  To  obtain  it  perfectly  pure, 
it  should  be  frozen  at  least  three  times,  the  portion  not  solidifying  being  removed  by  liltra- 
tion  through  calico.  The  unfrozen  portion  contains  hydrocarbons,  homologous  with  oletiant 
gas. 

Benzole  dissolves  free  iodine  and  bromine,  and  has  even  been  used  in  analysis  to  sepa- 
rate them  from  kelp  and  other  substances  containing  them.  They  must  of  course  be  sot 
free  before  acting  with  the  hydrocarbon.  The  presence  of  benzole  in  mixtures  may  easily 
be  demonstrated,  even  when  present  in  very  small  quantity,  by  converting  it  into  aniline, 
and  obtaining  the  characteristic  reaction  with  chloride  of  lime.  For  this  purpose  the  mix- 
ture is  to  be  dissolved  in  concentrated  nitric  acid  and  the  nitrobenzole  precipitated  by 
water.  The  fluid  is  then  agitated  with  ether,  which  dissolves  the  nitrocompound.  The 
ethereal  solution  is  mixed  with  an  equal  bulk  of  alcohol  and  hydrochloric  acid :  a  little 
granulated  zinc  being  added,  hydrogen  is  evolved,  and,  by  acting  in  a  nascent  state  on  the 
nitrocompound,  reduces  it  to  the  state  of  aniline.  The  base  is  then  to  be  separated  by  an 
excess  of  potash,  and  the  alkaline  fluid  is  shaken  with  ether  to  dissolve  the  base.  The 
ethereal  fluid  being  evaporated,  leaves  the  aniline.  On  adding  water  and  then  a  few  drops 
of  solution  of  chloride  of'  lime,  the  purple  color  indicative  of  aniline  is  immediately  pro- 
duced. {Hofmann.)  The  writer  of  this  article  has  by  this  process  detected  minute  traces 
of  benzole  in  mixtures  consisting  almost  entirely  of  homologues  of  olefiant  gas. — C.  G.  W. 

BERGAMOT.  {Derfjamote,  Fr.)  The  Citrus  berr/nmia,  a  citron  cultivated  in  the  centre 
ami  south  of  Europe.  By  distillation  from  the  rind  of  the  fruit  is  obtained  the  well-known 
essence  of  bergamot.  This  essential  oil  and  the  fruit  are  principally  obtained  from  Flor- 
ence and  Portugal.     See  Oils,  Essential. 

BERGAMOT.  A  coarse  tapestry,  said  to  have  been  invented  at  Bergamo,  in  Italy, 
made  of  ox  and  goats'  hair,  with  cotton  or  hemp. 

BERRY.  The  term  is  commonly  applied,  not  only  to  small  fruit,  but  in  some  cases  to 
seeds.  The  following  is  Professor  Lindley's  definition  of  a  berry  : — "  A  succulent  or  pulpy 
fruit  containing  naked  seeds,  or,  in  more  technical  language,  a  succulent  or  pulpy  pericarp, 
or  seed-vessel  without  valves,  containing  several  seeds,  which  are  naked,  that  is,  which  have 
no  covering  but  the  pulp  and  rind.  It  is  commonly  round  or  oval.  But  in  popular  lan- 
guage, berry  extends  only  to  smaller  fruits,  as  strawberry,  gooseberry,  &c.,  containing  seeds 
or  granules.  An  indehiscent  pulpy  pericarp,  many-celled  and  many-seeded  ;  the  attach- 
ment of  the  seeds  lost  at  maturity,  and  the  seeds  remaining  scattered  in  the  pulp." 

Berries  arc  used  in  some  of  the  processes  of  manufacture,  but  they  are  not  of  much 
importance. 

Bai/  Berries. — The  fruit  of  the  Laicrus  nobilis,  or  the  sweet  bay.  Both  the  leaves  and 
the  fruit  are  employed  as  flavorings.  A  volatile  oil,  the  oil  of  sweet  bai/,  is  obtained  liy  dis- 
tillation with  water;  and  a  fixed  oil,  by  l)ruising  the  berries,  and  boiling  them  for  some 
hours  in  water ;  this  oil,  called  also  Laurel  f<if,  is  im[)orted  from  Italy. 

Turkeji  Yellow  Berries. — The  unripe  fruit  of  the  lUinmnus  infectorius.  They  arc 
used  in  calico-printing,  producing  a  lively  but  fugitive  yellow  color. 

Persian  Yellow  Berries. — These  are  said  to  be  produced  by  the  same  species  of  plant ; 
Imt  the  color  is  considered  more  permanent,  and  they  fetch  higher  prices. 

Berries  of  Avignon. — Another  name  given  to  the  Turkey  and  Persian  berries. 

Juniper  Berries. — The  fruit  of  the  .funiperus  eomnuinis.  They  are  chiefly  used  for 
flavoring  gin  and  some  spirituous  cordials,  and  in  the  preparation  of  some  pharmaceutical 
'articles,  as  the  oil  of  junijjcr  and  the  compound  spirits  of  juniper. 

Bear  Berri/. — The  fruit  of  the  l/i'a  nrsi.     The  leaves  only  are  used  medicinally. 

Myrobolans. — The  fruit  of  a  tree  which  grows  in  India.  It  has  a  pale-y<'liow  color 
when  new,  hut  becomes  darker  by  age,  and  then  resembles  dried  plums.  It  contains  tannin, 
ami  has  Imtice  been  used  in  dyeing. 

BERTHOLLETIA.  A  plant  of  the  natural  order  Leqithidccc,  the  Bertholletia  excelsa. 
It  is  a  tree  of  large  dimensions,  forming  extensive  forests  on  the  banks  of  the  Orinoco. 


138  BEKYL. 

The  Portuguese  of  Para  have  for  a  long  time  driven  a  great  trade  with  the  nuts  of  this  tree, 
wiiich  the  natives  call  luvia,  and  the  Spaniards  Ahmndron.  They  send  cargoes  to  French 
(Juiana,  whence  they  are  shipped  for  England  and  Lisbon.  The  kernels  yield  a  large  quan- 
tity of  oil  well  suited  for  lamps. — Jlumholdt  and  Bonpland. 

BKKYL.  (Biril,  Fr.  ;  Beryl,  Germ.  ;  Stnarar/d,  Ital.)  A  beautiful  mineral  or  gem, 
usually  of  a  green  color  »f  various  shades,  passing  into  honey  yellow  and  sky  blue. 

Beryl  and  emerald  are  varieties  of  the  same  species,  the  latter  including  the  rich  green 
transparent  specimens  which  owe  their  color  to  oxide  of  chrome  ;  the  former  those  of  other 
colors  produced  by  oxide  of  iron.     Gmelin  gives  the  composition  of  beryl  as : — 

Silica C9-T0 

Alumina lY-GO 

Glucine 13-39 

Red  oxide  of  iron 0-24 

"  Beryls  of  gigantic  size  have  been  found  in  the  United  States,  at  Acworth  and  Grafton, 
New  IIam])shirc,  and  Royalston,  Mass.  One  beryl  from  Grafton  weighs  2,900  lbs. ;  it  is  32 
inches  through  in  one  direction,  and  22  in  another  transverse,  and  is  4  feet  3  inches  long. 
Another  crystal  from  this  locality,  according  to  Professor  Hubbard,  measures  45  inches  by 
24  in  its  diameters,  and  a  single  foot  in  length,  by  calculation,  weighs  1,0'76  lbs.,  making 
it,  in  all,  nearly  21  tons.     At  Royalston,  one  crystal  exceeded  a  foot  in  length." — Dana. 

Falae  Beryls  of  Comiyierce. — Some  of  the  natural  crystals  of  phosphate  of  lime  are 
introduced  as  beryls.  The  Apatite  is  sometimes  called  the  Saxony  beryl.  The  Chrysolite, 
known  by  the  Germans  as  the  Pierre  d' Asperge,  is  also  sold  as  the  beryl. 

Fluor  spars  of  diilerent  colors  are  sold  as  false  beryls,  false  emeralds,  false  amethysts, 
and  false  topazes.     These  are  fluate  of  lime. 

BETEL.  A  compound,  in  universal  use  in  the  East,  consisting  of  the  leaf  of  the  betel- 
pepper,  with  the  betel-nut,  a  little  catechu,  and  some  chunam,  (lime  obtained  by  calcining 
shells.)  This  is  almost  universally  used  throughout  central  and  tropical  Asia  ;  the  people 
are  unceasingly  masticating  the  betel. 

BETEL-LEAF.  The  leaf  of  the  pepper  vine,  {Piper  letel.)  This  plant  is  extensively 
cultivated  throughout  tropical  Asia,  and  forms  a  large  and  important  article  of  Eastern 
traffic. 

BETEL-NUT,  or  ARECA.  The  fruit  of  the  Areca  catechu.,  which  is  eaten  both  in  its 
ripe  and  its  unripe  state. 

BEUHEYL.  A  mining  term,  signifying  a  living  stream.  It  is  applied  by  the  tin- 
miners  to  any  portion  of  a  lode  or  of  the  rock  which  is  impregnated  with  tin. 

BEZOAR.  (The  most  probable  etymology  of  the  word  is  from  the  Persian  PudzaJn; 
i.  e.  expelling  poison. — Pewiy  Cyclopecdia.)  A  concretion  found  in  the  stomach  of  ani- 
mals of  the  goat  kind  ;  it  is  said  to  be  especially  produced  by  the  Cajira  gazella.  The 
finest  bezoar  is  brought  to  India  from  Borneo  and  the  shores  of  the  Persian  Gulf  The 
Capra  yEgagrus,  or  wild  goat  of  Persia  producing  this  concretion,  which,  by  way  of  emi- 
nence, was  called  the  Lapis  bezoar  orientalis.  The  bezoars,  which  were  supposed  to  cure 
all  diseases,  have  been  found,  by  the  analysis  of  Fourcroy  and  Yauquelin  and  of  Proust,  to 
be  nothing  more  than  some  portions  of  the  food  of  the  animal  agglutinated  into  a  ball  with 
pho.sphate  of  lime. 

J'o.ssil  bezoar  is  found  in  Sicily,  in  sand  and  clay  pits.  They  are  concretions  of  a  purple 
color  around  some,  usually  organic,  body,  and  the  size  of  a  walnut.  Fossil  bezoar  is  some- 
times called  Sicilian  earth ;  and  it  appears  to  be  of  a  similar  character  to  Armenian  bole. 

Bezoar  Mineral. — An  old  preparation  of  the  oxide  of  antimony. 

BICARBOXATES.  The  ordinary  carbonates  of  potash  and  soda  have  a  strong  alkaline 
reaction  and  caustic  taste,  making  them  unfit  for  many  purposes  where  a  soluble  carbonate 
is  rcfpiired.  Moreover,  there  are  many  uses  to  which  they  are  applied,  rendering  it  de- 
sirable that  as  large  an  amount  of  gas  as  possible  should  be  given  off  on  the  addition  of  a 
stronger  acid. 

Bicarbonate  of  Potash. — There  are  several  modes  of  converting  the  carbonate  into 
bicarl)onate.  The  most  economical  is  by  exposing  the  salt  to  a  current  of  carl)onic  acid. 
For  this  purpose  some  manufacturers  place  it,  slightly  moistened,  on  stoneware  trays,  and 
allow  the  vapors  of  burning  coke  to  travel  slowly  over  it.  The  sources  of  the  gas  used  in 
this  manufacture  will  vary  according  to  the  locality  in  which  it  is  undertaken.  It  is  not 
unusual  to  produce  it  by  the  action  of  sulphuric  acid  on  limestone.  The  gas  generated  in 
fermentation  has  been  employed,  and  even  that  which  in  some  places  issues  from  the  earth. 
The  l)icarI)onate  of  potash  is  far  less  soluble  than  the  carbonate,  as  it  requires  four  parts  of 
cold  water  for  solution,  whereas  the  carbonate  dissolves  in  0'9  of  its  weight  of  water  at  54° 
F.  Consequently,  if  a  strong  solution  is  saturated  with  carbonic  acid,  the  bicarbonate  crys- 
tallizes out.  When  common  pearl  ashes  are  dissolved  in  water,  and  the  gas  is  passed  in,  a 
large  quantity  of  a  white  i)recipitatc  is  often  thrown  down  ;  it  consists  chiefly  of  silica,  but 
often  contains  alumina  and  other  matters.     Considerable  beat  is  developed  when  moistened 


BISCUITS.  139 

carbonate  of  potash  is  exposed  to  a  current  of  carbonic  acid  gas.  When  carbonate  of  pot- 
asli  is  dissolved  in  water,  and  gradually  treated  with  acetic  acid,  so  as  to  form  acetate  of 
potash,  by  no  means  the  whole  of  the  carbonic  acid  is  expelled,  and  a  point  is  arrived  at 
when  a  considerable  quantity  of  crystals  is  deposited  ;  they  consist  of  very  pure  bicarbonate 
of  potash.  In  making  acetate  of  potash  on  the  large  scale,  the  quantity  of  crystalline  pre- 
cipitate obtained  in  this  manner  is  sometimes  very  large.  Bicarbonate  of  potash  is  usually 
tolerably  pure.  If  well  crystallized,  all  the  impurities  remain  in  the  mother-liquor,  and  on 
heatino-  to  redness  almost  exactly  the  theoretical  amount  of  residue  is  left,  viz.  69-05  per 
cent.  °  Crystallized  bicarbonate  of  potash  always  contains  one  equivalent  of  water,  its 
formula  being  KO,  2C0-  -j-  HO. 

Bicarbonate  of  Sod't. — This  salt  is  obtained  by  the  same  methods  as  the  salt  of  potash. 
The  crystals  have  a  corresponding  formula  to  the  potash  salt ;  namely,  NaO,  2C0-  -\-  IK). 
It  requires  about  13  parts  of  water  at  GO'  to  dissolve  it.  When  pure,  100  parts  leave  G3-18 
of  NaO,  CO-  on  ignition. 

The  biearbonates  of  potash  and  soda  lose  carbonic  acid  by  the  boiling  of  an  aqueous 
solution. 

Alodern  theoretical  chemists  regard  carbonic  acid  as  being  bibasic,  the  true  formula 
being  C'O^  instead  of  CO^.  There  can  be  little  doubt  that  this  view  is  the  correct  one,  and 
it  has  the  advanta2;e  of  explaining  why  the  biearbonates  are  neutral  instead  of  acid  salts. 
Moreover,  C^O*  corresponds  to  4  volumes,  like  organic  substances  generally  ;  whereas,  if  we 
assume  CO^  as  one  atom  of  the  gas,  we  are  compelled  to  admit  a  2-volume  formula. — 
C.  G.  W. 

BIDERY.  An  Indian  alloy  of  considerable  interest,  named  Bidery  from  Bider,  a  city 
N.  E.  of  Hyderabad.  Many  articles  are  made,  remarkable  for  elegance  of  form  and  for 
gracefully-engraved  patterns.  Although  the  groundwork  of  this  composition  appears  of  a 
blackish  color,  its  natural  tint  is  that  of  pewter  or  zinc. 

Dr.  Hej-ne  says  it  is  composed  of,  copper,  16  ;  lead,  4  ;  tin,  2  ;  and  to  every  3  ounces 
of  alloy  16  ounces  of  spelter  (that  is,  of  zinc)  are  added,  when  the  alloy  is  melted  for  use. 
To  give  the  esteemed  black  color  and  to  bring  out  the  pattern,  it  is  dipped  in  a  solution  of 
sal  ammoniac,  saltpetre,  common  salt,  and  blue  vitriol.  Dr.  Hamilton  saw,  zinc,  12,360 
grains  ;  copper,  400  ;  and  lead,  414  ;  melted  together  under  a  mixture  of  resin  and  bees' 
wax  introduced  into  the  crucible  to  prevent  calcination  ;  it  was  then  poured  into  moulds  of 
baked  clay,  and  the  articles  handed  over  to  be  turned  in  a  lathe.  • 

Though  called  bidery,  and  sometimes  vidry,  it  is  manufactured  in  other  places.  In  some 
parts  of  the  Nizam's  dominions,  specimens  were  obtained,  for  the  Exhibition  of  1851,  of 
great  beauty. 

Bidery  does  not  rust,  yields  little  to  the  hammer,  and  breaks  only  when  violently  beaten. 
According  to  Dr.  Hamilton,  bidery  is  not  nearly  so  fusible  as  zinc  or  tin,  but  melts  more 
easily  than  copper. — Dr.  Royle,  Lecture  on  the  Great  Exhibition. 

BIJOUTRY.  {Bijouterie,  Fr.)  Jewellery ; — the  manufacture  of  and  dealing  in  jewel- 
lery. This  work  is  not  the  place  in  which  to  describe  the  almost  endless  variety  of  articles 
which  come  under  this  denomination.  The  principal  places  for  the  manufacture,  in  Eng- 
land, are  Birmingham  and  London.  The  trade  in  jewellery  forms  one  of  the  most  impor- 
tant branches  of  French  commerce  ;  on  which  a  French  writer  says  : — "  La  bijouterie  est 
une  des  branches  les  plus  importantes  du  commerce  francais,  et  c'cst  elle  cjui  constate,  de 
la  maniere  la  plus  evidentc,  notre  supcriorite  dans  les  arts  du  dessin  et  les  progres  toujours 
croissans  de  I'industrie  Parisienne.  Dans  cctte  partie  essenticlle,  elle  n'a  pas  de  rivaux,  ct 
elle  rend  tributaire  de  notre  pays  prcsque  toute  I'Europe,  et  une  grande  partie  de  TAsie  et 
de  I'Amcrique." 

The  ordinary  practice  has  been  to  divide  articles  of  this  character  into  two  principal 
kinils — fine  jewellery,  and  false  jewellery,  (bijoutier  en  fin  and  bijoutier  en  faux.)  Another 
division,  among  the  French  jewellers  especially,  has  been  to  adopt  four  classes  :  1,  line  jew- 
ellery, which  is  all  gold  ;  2,  silver  jewellery ;  3,  false  jewellery  ;  and,  4,  jewellery  of  steel 
or  iron, 

BISCUITS.  The  manufacture  of  fancy  biscuits,  which  in  former  times  was  confined  to 
the  pastry-cook  and  confectioner,  has  of  late  years  assumed  considerable  importance,  and 
several  firms  are  now  exclusively  engaged  in  this  branch  of  industry,  the  products  of  which 
are  sold  under  an  extraordinary  variety  of  names.  Some  of  these,  namely,  the  "  ])laiii  bis- 
cuit, arrow-root,  captain,  brown  meal,  cinnamon,  caraway,  vanilla  biscuits,"  &c.,  are  intelli- 
gible enough  ;  Ijut,  if  we  except  "  Aberncthy  biscuit,  niaccaroon.s,  and  cracknels,"  with  the 
-names  of  which  the  public,  from  long  usage,  are  familiar,  the  rest  of  the  products  of  t!u> 
modern  biscuit  maker,  "  Africans,  Jamaica,  tjueen's  routs,  ratafias,  Bath  and  other  sorts  of 
Olivers,  exhiljition,  ring.^  and  fingci-s,  i)ic-nics,  cuddy,"  &c.,  &c.,  forms  a  list  of  upwards  of 
eighty  fanciful  names,  all  expressive  of  articles  of  difi'erent  form,  appearance,  and  taste, 
made  of  nearly  the  same  materials,  with  but  little  variation  in  the  proportion  in  which  they 
are  used, — the  principal  ingredients  in  all  being  flour  and  water,  butter,  milk,  eggs,  and 
caraway,  nutmeg,  cinnamon,  or  mace,  or  ginger,  or  essence  of  lemon,  neroli,  or  orange- 


140  BISCUITS. 

flower  water,  called,  in  technical  language,  "  flavorings."  The  kneading  of  these  materials 
is  alwavs  performed  by  a  kneading  or  mixing  machine.  The  dough  or  paste  produced  is 
passed  several  times  between  two  revolving  cylinders  adjusted  at  a  proper  distance,  so  as  to 
obtain  a  flat,  perfectly  homogeneous  mass,  slab,  or  sheet.  This  is  transferred  to  a  stamping 
or  cutting  machine,  consisting  of  two  cylinders,  through  which  the  sheet  of  homogeneous 
paste  has  to  pass,  and  by  which  it  is  laminated  to  the  proper  thickness,  and  at  the  same  time 
jiushed  under  a  stamping  and  docking  frame,  which  cuts  it  into  discs,  or  into  oval  or  other- 
wise shaped  pieces,  as  occasion  may  require.  The  stamps  or  cutters  in  the  frame  being 
internally  provided  with  prongs,  push  the  cut  pieces  of  dough,  or  raw  cakes,  out  of  the  cut- 
ting frame,  and  at  the  same  time  dock  the  cakes,  or  cut  pieces,  with  a  series  of  holes,  for 
the  subsequent  escape  of  the  moisture,  which,  but  for  these  vents,  would  distort  and  spoil 
the  cake  or  biscuit  when  put  in  the  oven.  The  temperature  of  the  oven  should  be  so  regu- 
lated as  to  be  perfectly  uniform,  neither  too  high  nor  too  low,  but  just  at  such  a  heat  as  is 
sufiicient  to  give  the  biscuits  a  light  brown  color.  For  such  a  purpose  the  hot  water  oven 
of  Mr.  Perkins,  or  that  of  Mr.  Koland,  is  the  best  that  can  possibly  be  used.  (See  Bread.) 
Roland's  oven  offers  the  peculiar  advantage  that,  by  turning  the  screw,  the  sole  of  the  oven 
can  be  brought  nearer  to  the  top,  and  a  temperature  is  thus  obtained  suitable  for  baking 
thoroughly,  without  burning,  the  thinnest  cakes. 

One  of  the  most  curious  branches  of  the  baker's  craft  is  the  manufacture  of  ginger- 
bread, which  contains  such  a  proportion  of  molasses  that  it  cannot  be  fermented  by  means 
of  yeast.  Its  ingredients  are  flour,  molasses  or  treacle,  butter,  common  potashes,  and  alum. 
After  the  butter  is  melted,  and  the  potashes  and  alum  are  dissolved  in  a  little  hot  water, 
these  three  ingredients,  along  with  the  treacle,  are  poured  among  the  flour  which  is  to  form 
the  body  of  the  bread.  The  whole  is  then  incorporated  liy.  mixture,  and  kneading  into  a 
stiff  dough.  Of  these  five  constituents  the  alum  is  the  least  essential,  although  it  makes 
the  bread  lighter  and  crisper,  and  renders  the  process  more  rapid ;  for  gingerbread,  dough 
requires  to  stand  over  for  several  days,  some  8  or  10,  before  it  acquires  the  state  of  porosity 
which  qualifies  it  for  the  oven ;  the  action  of  the  treacle  and  alum  on  the  potashes,  in 
evolving  carbonic  acid,  seems  to  be  the  gassifying  principle  of  gingerbread  ;  for  if  carbon- 
ate of  potash  is  withheld  from  the  mixture,  the  bread,  when  baked,  resembles,  in  hardness, 
a  piece  of  wood. 

Treacle  is  always  acidulous.  Carbonate  of  magnesia  and  soda  may  be  used  as  substitutes 
for  the  potashes.  *  Dr.  Colquhoun  has  found  that  carbonate  of  magnesia  and  tartaric  acid 
may  replace  the  potashes  and  the  alum  with  great  advantage,  aflbrding  a  gingerbread  fully 
more  agreeable  to  the  taste,  and  much  more  wholesome  than  the  common  kind,  which  con- 
tains a  notable  quantity  of  potashes.  His  proportions  are :  1  lb.  of  flour,  ^  of  an  ounce  of 
carbonate  of  magnesia,  and  -J-  of  an  ounce  of  tartaric  acid,  in  addition  to  the  treacle,  but- 
ter, and  aromatics,  as  at  present  used.  The  acid  and  alkaline  earth  must  be  well  diffused 
tlirough  the  whole  dough  ;  the  magnesia  should,  in  fact,  be  first  of  all  mixed  with  the  flour. 
Tlie  melted  butter,  the  treacle,  and  the  acid  dissolved  in  a  little  water,  are  poured  all  at 
once  amongst  the  flour,  and  kneaded  into  a  consistent  dough,  which  being  set  aside  for  half 
an  hour  or  an  hour,  will  be  ready  for  the  oven,  and  should  never  be  kept  unbaked  for  more 
than  2  or  3  hours.  The  following  more  complete  recipe  is  given  by  Dr.  Colquhoun  for 
making  thin  gingerl)read  cakes : — Flour  1  lb.,  treacle  4  lb.,  raw  sugar  -^  lb.,  butter  2 
ounces,  carbonate  of  magnesia  ^  ounce,  tartaric  acid  ^  ounce,  ginger  ^  ounce,  cinnamon  ^ 
ounce,  nutmeg  1  ounce.  This  compound  has  rather  more  butter  than  common  thin  ginger- 
bread. In  addition  to  these,  yellow  ochre  is  frequently  added  by  cheap  gingerbread- 
makers,  and  altogether  this  preparation,  more  generally  consumed  by  children,  is  very 
objectionable. 

"  Puff-paste  "  is  a  preparation  of  flour  and  butter,  which  is  in  great  demand  not  only  at 
the  pastry-cooks',  but  in  almost  every  private  family.  Take  a  certain  quantity  of  flour,  say 
half  a  pound,  put  it  upon  a  wooden  board,  make  a  hole  or  depression  in  the  centre,  and 
mix  it  with  somewhat  less  than  half  a  ]iint  of  cold  water,  so  as  to  make  a  softish  paste  ;  dry 
it  off  from  the  board  by  shaking  a  little  flour  over  and  under,  as  is  well  known,  but  do  not 
"  work  it "  more  than  you  can  help.  Take  now  a  quarter  of  a  pound  of  fresh  butter,  which 
sliould  be  ax  hard  as  posxihle,  (and  therefore  it  should  be  kept  in  as  cold  a  place  as  practi- 
cable, the  ice  closet,  if  procurable,  being  the  best  place,)  and  squeeze  out  all  the  water,  or 
buttermilk  which  it  contains,  by  kneading  it  with  one  hand  on  the  board.  This  operation 
is  called  in  French  "  martirr  le  hoirrr."  Roll  now  the  paste  prepared  as  above  into  a  flat, 
thick,  square  slab,  extending  about  0  or  7  inches  ;  lay  the  pat  of  butter,  treated  as  above, 
in  the  middle  of  the  slab  of  paste,  and  so  wrap  the  butter  up  into  it  by  folding  the  sides  of 
the  paste  all  round  over  it ;  roll  the  whole  mass  gently  with  the  rolling-pin,  so  as  to  form  a 
thick  sheet,  put  it  upon  a  tin  plate,  or  tray,  cover  it  with  a  linen  cloth  wetted  with  water 
as  cold  as  possible,  and  leave  the  whole  at  rest  for  about  a  quarter  of  an  hour  in  a  cold 
place.  At  the  end  of  that  time,  roll  the  mass  with  the  rolling-pin  into  a  sheet  about  15  or 
IG  inches  long,  and  fold  it  into  three,  one  over  the  other;  roll  it  out  again  into  a  sheet  as 
before,  and  again  fold  it  into  three,  one  over  the  other,  as  before,  and  repeat  this  operation 


BISMUTH. 


141 


once  more,  making  three  times  in  all.  Put  the  square  mass,  with  a  wet  cloth  upon  it,  in  a 
cold  place  for  another  quarter  of  an  hour,  as  before,  and  at  the  end  of  that  time  roll  it  out 
with  the  rolling-pin,  and  fold  it  into  three,  one  over  the  other,  as  above ;  and  do  this  once 
more,  making  five  times  in  all,  after  which  the  paste  is  ready  for  use.  Care  must  be 
taken,  during  the  rolling,  continually  to  dust  the  board  and  the  paste  with  a  little  flour,  to 
prevent  sticking.  The  paste  may  now  be  placed  in  the  dish,  or  tins,  in  which  it  is  to  be 
baked,  taking  care  to  cut  the  protruding  edges  with  a  pointed  and  sharp  knife,  so  as  to 
leave  the  paste  alL  round  with  a  clean  cut  edge,  for  otherwise  it  will  not  puff  up  or  sivell. 
The  thick  edges  of  pies  and  tarts  are  made  by  cutting  strips  of  the  paste  with  the  knife,  and 
carefully  laying  them  on  all  round,  taking  care  to  leave  the  edr/es  quite  sharp.  The  pre- 
pared articles  are  then  put  in  an  oven,  previously  brought  to  a  good  heat,  and  the  elastic 
vapor  disengaged  from  the  butter  and  water  will  at  once  cause  the  paste  to  swell  into 
parallel  layers  of  great  tenacity,  and  apparcntli/  light,  but  really  very  heavy,  since  each  of 
these  thin  laminai  is  compact  and  distinct.  PuiF-paste  is  indigestible.  It  is  essential  to  the 
success  of  the  operation,  that  the  floor  of  the  oven  should  be  hot. — A.  N. 

BISMUTH.  {Bismuth,  Fr. ;  Bisimdh,  Germ.)  The  following  are  the  principal  ores  of 
bismuth  ;  the  first  is  the  source  of  the  metal  used  in  the  arts  : — 

Bismuth,  Native,  is  whitish,  with  a  faint  reddish  tinge,  and  a  metallic  lustre  which  is 
liable  to  tarnish.  Streak,  silver-white.  Hardness,  2  to  2'5  ;  specific  gravity,  9-72Y.  It  is 
brittle  when  cold,  but  slightly  malleable  when  heated.  It  generally  occurs  in  a  dendritic 
form.  It  fuses  readily  at  476"  F.  Beautiful  crystals  can  be  formed  artificially  by  fusion 
and  subsequent  slow  cooling. 

Native  bismuth  has  been  found  associated  with  other  minerals :  in  Cornwall,  at  Huel 
Sparnon,  near  Redruth,  when  that  mine  was  worked ;  at  Trugoe  Mine,  near  St.  Colomb, 
((Jregg,)  and  at  the  Consolidated  Mines,  St.  Ives,  Caldbeck  Fells,  in  Cumberland,  with  ores 
of  cobidt. 

Bismtitldne,  or  sulphuret  of  bismuth,  occurs  either  in  acicular  crystals,  or  with  a  foli- 
ated, fibrous  structure.  It  is  isomorphous  with  stibnite.  Hardness,  2  to  2'5  ;  specific 
gravity,  6-4  to  6'9.  It  is  composed  of  bismuth,  81"6  ;  sulphur,  18'4.  It  fuses  in  the  flame 
of  a  candle. 

Bismuthine  occurs  in  Cornwall,  at  Botallack,  and  associated  with  tin  at  St.  Just,  and 
with  copper  at  the  mines  near  Redruth  and  Camborne. 

Bismuth  Ochre. — A  dull  earthy  mineral,  found  in  the  Royal  Restormel  Iron  Mine,  and 
in  small  quantities  in  the  parish  of  Roach,  in  Cornwall.  Its  composition  is  stated  by  Lam- 
padius  to  be  : — 

Oxide  of  bismuth -         -80 '4 

Oxide  of  iron  .-..-..-..         5-1 

Carbonic  acid 4"1 

"Water 31 

Telluric  Bismuth. — Tetradymite, — occurs  in  Cumberland,  at  Brandy  Gill,  Carrock  Fells, 
(Gregg.)     Its  composition  is  : — 

Bismuth 83-30 

Tellurium 6-65 

Sulphur G-13 

Selenium ".         -  1.22 

Acicular  Bismuth. — Aikinite — called  also  Xeedle  Ore,  and  the  plumbo-cupriferous 
sulphide  of  bismuth — is  composed  of  sulphur,  10  ;  bismuth,  34-02;  lead,  35-09;  copper, 
11-79. 

Carbonate  of  Bismuth. — Bismutite.  This  ore  is  composed  of  a  mechanical  mixture  of 
the  carbonates  of  bismuth,  of  iron,  and  of  copper. 

Cupreoics  Bismuth. — Tannenite,  is  sulphur,  18-83;  bismuth,  62-10  ;  copper,  18-72. 

This  metal  is  also  found  associated  witli  selenium  and  tellurium. 

Bismuth  may  be  regarded  as  the  most  remarkable  of  the  dia-magnetic  bodies,  standing, 
indeed,  at  the  head  of  the  class,  in  the  same  way  as  iron  does  at  the  head  of  the  magnetic 
order  of  substances.* 

In  lire's  "  Dictionary  of  Chemistry  "  will  be  found  various  methods  for  the  determina- 
tion of  bismuth.  The  following  processes,  however,  appear  so  useful  as  to  warrunt  their 
insertion  in  this  place  : — To  detect  small  quantities  of  lead  in  Ijisnmth,  or  in  bisnnilh  com- 
l)()unds.  Chapman  brings  the  somewhat  flattened  head,  reduced  l)efore  the  blowpipe,  in 
contact  with  some  moist  basic  nitrate  of  tero.xide  of  bismuth,  when,  in  a  short  time,  in  con- 
sequence of  the  reduction  of  the  bismuth  ))y  the  K-ad,  arborescent  sprigs  of  bismuth  are 
formed  around  the  test  specimen.  Since  zinc  and  iron  interfere  with  this  reaction,  they 
must  1)0  previously  removed,  the  former  by  fusion  with  soda,  the  latter  with  soda  and  borax, 
in  the  reducing  flame. 

*  Consult  Do  la  Rive's  Treatise  on  Electricity,  translated  by  Charles  V.  Walker,  P.  R.  S. 


142  BITTER  PRINCIPLE. 

Lead  and  bismuth  can  easily  be  quantitatively  separated  from  each  other  by  the  follow- 
ing method,  proposed  l)y  Ullgren  : — The  solution  of  the  two  metals  is  precipitated  by  car- 
bonate of  ammonia,  and  the  carbonates  are  then  dissolved  by  acetic  acid,  and  a  blade  of 
pure  lead,  the  weight  of  which  is  ascertained  beforehand,  is  plunged  in  the  solution.  This 
blade  must  be  completely  immersed  in  the  liquor.  The  vessel  is  then  corked  up,  and  the 
experiment  is  left  for  several  hours  at  rest.  ^The  lead  precipitates  the  bismuth  in  the 
metallic  form.  When  the  whole  of  it  is  precipitated,  the  blade  of  lead  is  withdrawn, 
washed,  dried,  and  weighed.  The  bismuth  is  collected  on  a  filter,  washed  with  distilled 
water  which  has  been  i)reviously  boiled,  and  cooled  out  of  contact  of  the  air ;  this  metal  is 
then  treated  with  carbonate  of  ammonia,  and  the  precipitate  which  is  left,  after  washing  and 
ignition,  is  then  weighed.  The  total  lo.«s  of  the  metallic  lead  employed  indicates  how  much 
oxide  of  lead  must  be  subtracted  from  the  total  weight  of  the  protoxide  of  lead  obtained. — 
£.  PeHijot''s  Edition  of  Rose. 

Oxide  of  bismuth  can  be  separated,  by  means  of  sulphohydric  acid,  from  all  the  oxides 
which  cannot  be  precipitated  from  an  acid  solution  by  this  reagent.  Yet,  when  the  precipi- 
tate of  sulphide  of  bismuth  is  intended  to  be  made  by  moans  of  sulphohydric  acid,  it  is 
necessary  to  take  care  to  dilute  with  water  the  solution  of  the  oxide  of  bismuth.  But  as 
the  .solutions  of  bismuth  are  rendered  milky  by  water,  acetic  acid  should  first  be  added  to 
the  liquor,  which  prevents  its  beconiing  turbid  when  water  is  poured  into  it. — Roue. 

BITTER  PRINCIPLE.  {Amcr,  Fr.  ;  Bitterstoff,  Germ.)  The  "  bitter  principles  " 
consist  of  bodies  which  may  be  extracted  from  vegetable  productions  by  the  agency  of 
water,  alcohol,  or  ether.  These  are  not  of  much  importance  in  the  arts,  with  a  few  ex- 
ceptions. 

Lnpulin. — For  example,  the  bitter  principle  of  the  hop  is  used  for  preserving  beer.  It 
is  a  reddish-yellow  powder,  obtained  from  hops  by  digestion  in  alcohol,  which  is  evaporated ; 
then  the  extract  is  dissolved  in  water,  and  the  fluid  saturated  with  lime.  This  is  evaporated, 
and  the  residuary  ma.ss  treated  with  alcohol  or  ether. 

Qitanain  is  the  bitter  principle  of  quassia ;  Absinthin^  that  of  wormwood  ;  and  Gen- 
iianin,  that  of  gentian,  &c. 

BITUMEN,  or  ASPIIALTUM.  Bitumen  comprises  several  distinct  varieties,  of  which 
the  two  most  important  are  asphaltum  and  naphtha. 

Axphaltum  is  solid,  and  of  a  black,  or  brownish-black,  color,  with  a  couchoidal  brilliant 
fracture. 

Kaphtha. — Liquid  and  colorless  when  pure,  with  a  bituminous  odor. 

There  are  also  the  eartht/^  or  daggy  mineral  pitch — petroleum — a  dark-colored  fluid 
variety,  containing  much  naphtha,  and  maltha,  or  mineral  tar. 

Bitumen  in  all  its  varieties  was  known  to  the  ancients.  It  was  used  by  them,  combined 
with  lime,  in  their  buildings.  Not  only  do  we  find  the  ruined  walls  of  temples  and  palaces, 
in  the  East,  with  the  stones  cemented  with  this  material,  but  some  of  the  old  Roman  cas- 
tles in  this  country  are  found  to  hold  bitumen  in  the  cement  by  which  their  stones  are 
secured.  At  Agrigentum  it  was  burnt  in  lamps,  and  called  "  Sicilian  oil."  The  Egyptians 
used  it  for  embalming. — Dana. 

Sjirings  of  which  the  waters  contain  a  mixture  of  petroleum,  and  the  various  minerals 
allied  to  it — as  bitumen,  asphaltum,  and  pitch — are  very  numerous,  and  are,  in  many  cases, 
undoubtedly  connected  with  subterranean  heat,  which  sublime  the  more  subtle  parts  of  the 
bituminous  matters  contained  in  rocks.  Many  springs  in  the  territory  of  Modena  ami 
Parma,  in  Italy,  produce  petroleum  in  abundance ;  but  the  most  powerful  perhaps  yet 
known  are  those  of  Irawadi,  in  the  Burman  empire.  In  one  locality  there  are  said  to  be 
520  wells,  which  yield  annually  40,000  hogsheads  of  petroleum. 

Fluid  bitumen  is  seen  to  ooze  from  the  bottom  of  the  sea  on  both  sides  of  the  island  of 
Trinidad,  and  to  rise  up  to  the  surface  of  the  water.  It  is  stated  that,  about  seventy  years 
ago,  a  spot  of  land  on  the  western  side  of  Trinidad,  nearly  half-way  between  the  capital  and 
an  Indian  village,  sank  suddenly,  and  was  immediately  replaced  by  a  small  lake  of  ))itch. 
In  this  way,  probably,  was  formed  the  celebrated  Great  Pitch  Lake.  Sir  ("harks  LycU 
remarks : — "  The  Orinoco  has  for  ages  been  rolling  down  great  quantities  of  woody  and 
vegetable  bodies  into  the  surrounding  sea,  where,  by  the  influence  of  currents  and  eddies, 
they  may  be  arrested  and  accumulated  in  particular  places.  The  frequent  occurrence  of 
earthquakes,  and  other  indications  of  volcanic  action  in  those  parts,  lend  countenance  to  the 
opinion  that  these  vegetable  substances  may  have  undergone,  l)y  the  agency  of  subterranean 
fire,  tho.«e  transformations  or  chemical  changes  which  produce  petroleum  ;  and  this  may,  by 
the  same  causes,  be  forced  up  to  the  surface,  where,  by  exposure  to  the  air,  it  becomes 
inspissated,  and  forms  the  different  varieties  of  pure  and  earthy  pitch,  or  asphaltum,  so 
abundant  in  the  island." 

The  Pitch  Lake  is  one  and  a  half  miles  in  circumference ;  the  bitumen  is  soliil  and  cold 
near  the  shores,  but  gradually  increases  in  temperature  and  softness  towards  the  centre, 
whore  it  is  lioiling.  The  solidified  l)itumen  appears  as  if  it  had  cooled,  as  the  .surface  boiled, 
in  large  bubbles.     The  ascent  to  the  lake  from  the  sea,  a  distance  of  three-quarters  of  a 


BLACK  FLUX.  143 

mile,  is  covered  with  a  hardened  pitch,  on  which  trees  and  vegetabes  flourish  ;  and  about 
Point  la  Braye,  the  masses  of  pitch  look  like  black  rocks  among  the  foliage  :  the  lake  is 
underlaid  by  a  bed  of  mineral  coal. — Jfaiiross,  quoted  by  Dana. 

The  Earl  of  Dundonald  remarks,  that  vegetation  contiguous  to  the  lake  of  Trinidad  is 
most  luxuriant.  The  best  pine-apples  in  the  West  Indies  (called  black  pines)  grow  wild 
amid  the  pitch. 

Asphaltum  is  abundant  on  the  shores  of  the  Dead  Sea.  It  occurs  in  some  of  the  mines 
of  Derbyshire,  and  has  been  found  in  granite,  with  quartz  and  fluor  spar,  at  Poldicc,  in 
Cornwall.  There  is  a  remarkable  bituminous  lime  and  sandstone  of  the  region  of  Bechcl- 
l)ronn  and  Lobsann,  in  Alsace.  From  the  observations  of  Daubree,  we  learn  that  probably 
this  bitumen  has  had  its  origin  as  an  emanation  from  the  interior  of  the  earth  ;  and  indeed, 
in  Alsace,  with  the  great  elevated  fissure  of  the  sandstone  of  the  Vosges,  a  fissure  wliich 
was  certainly  open  before  the  deposit  of  the  Trias,  but  was  not  yet  closed  during  the  ter- 
tiary epoeh,  affording  during  this  latter,  moreover,  an  opportunity  for  the  deposition  of 
spathic  iron  ore,  iron  pyrites,  and  heavy  spar. — Annales  des  Mines. 

Elastic  Bitumen,  called  also  mineral  caoutchouc  and  elatcrite,  was  first  observed  in 
Derbyshire,  in  the  forsaken  lead  mine  of  Odin,  by  Dr.  Lister,  in  167-3,  who  called  it  a  sub- 
terranean fungus.  It  was  afterwards  described  by  Hatchett.  The  analysis  of  this  variety, 
by  Johnston,  gave  the  following  as  its  composition  : — 

Carbon,  83 '47 Hydrogen,  13-28 

Two  descriptions  of  elastic  bitumen  were  analyzed  by  M.  Henry,  fils,  ("  Ann.  des  Mines.") 
He  states  the  English  to  have  been  in  brown  masses,  slightly  translucid,  of  a  greenish  color, 
soft,  elastic,  burning  with  a  white  flame,  and  giving  off"  a  bituminous  odor,  and  of  specific 
gravity  0-9  to  r23,  and  obtained  from  Derbyshire. 

The  French  elastic  bitumen  generally  resembled  the  English,  excepting  that  it  was 
opaque,  and  floated  on  water.     It  was  discovered  at  the  coal  mines  of  Montrelais. 

Carbon  .         -         .         -         . 

•     Hydrogen  -         -         -         -         - 

Nitrogen  ----- 

Oxygen  


Of  ordinary  bitumen,  we  have  analyses  of  two  specimens ; 
tained  his  sample  from  the  Auvergne  ;   and  the  other  by  Boussingault,  which  was  a  Peru- 
vian specimen : — 

Auvergne.  reruvinn. 

Carbon 76-13         -  -         -  88-63 

Hydrogen 9-41         -  -         -  9-69 

Oxygen 10-34  [  j 


English. 

French 

0.5225 

- 

- 

- 

0-5826 

00749 

- 

- 

. 

0-0489 

0-0015 

. 

. 

- 

0-0010 

0-4011 

0-3675 

1-0000 

1-0000 

wo  specimens : 

one 

by 

Ebelmen,  who  ob 

Nitrogen 2 

Ash 1-80 


-34) 
.32  f 


100-00  100-00 

BLACK  BAND.  A  variety  of  the  carbonates  of  iron,  to  which  attention  was  first  callccl 
by  Mr.  Mushet,  at  the  commencement  of  the  present  century.  The  iron  manufacture  of 
Scotland  owes  its  present  important  position  to  the  discovery  of  the  value  of  the  lilack  band 
iron  stone.  This  ore  of  iron  is  also  found  in  several  parts  of  the  coal  basin  of  South  Wales, 
and  in  the  north  of  Ireland.     See  Iron. 

Chemical  examination  of  the  black  band,  from  the  neighborhood  of  Airdrie,  about  ten 
miles  east  of  Glasgow,  gives  the  following  composition  : — 

Carbonic  acid        -         - 33-17 

Protoxide  of  iron 5303 

Lime 333 

Magnesia 1-77 

Sihca 1-10 

Alumina 063 

Peroxide  of  iron 0-23 

Bituminous  matter 3  03 

Water  and  loss Til 


100-00 
BLACK  FLUX.     An  intimate  mixture  of  charcoal  and  carbonate  of  potash,  obtained 
by  calcining  bitartratc  of  potash.     Generally,  the  crude  tartar  of  conunerce  is  tised  for  this 

purpose. 


144  BLACKING  FOE  SHOES. 

BLACKING  FOR  SHOES.  According  to  the  "  Scientific  American,"  a  good  paste 
blacking  is  made  of  4  lbs.  of  ivory  black,  S  lbs.  of  molasses,  9  oz.  of  hot  sperm  oil,  1  oz. 
of  gum  urabic,  and  12  oz.  of  vinegar,  mixed  together,  and  stirred  frequently  for  six  days  ;  it 
is  then  fit  for  use. 

Blacking  consists  of  a  black  coloring  matter,  generally  bone  black,  and  substances  that 
acquire  a  gloss  by  friction,  such  as  .«ugar  and  oil.  The  usual  method  is  to  mix  the  bone 
black  with  sperm  oil :  sugar,  or  moliu«ses,  with  a  little  vinegar,  is  then  well  stirred  in,  and 
strong  sulphuric  acid  is  added  gradually.  The  acid  produces  suljihate  of  Hme  and  acid 
phosphate  of  lime,  which  is  soluble  :  a  tenacious  paste  is  formed  by  these  ingredients,  which 
can  be  smoothly  spread  ;  the  oil  serving  to  render  the  leather  pliable.  This  forms  a  liquid 
blacking.  Paste  blacking  contains  less  vinegar.  In  Germany,  according  to  Licbig,  black- 
ing is  made  by  mixing  bone  black  with  half  its  weight  of  molasses,  and  one-eighth  of  its 
weight  of  hydrochloric  acid,  and  oifb-fourth  of  its  weight  of  strong  sulphuric  acid,  mixing 
with  water,  to  form  an  unctuous  paste. — Report  of  the  Progress  of  Science  and  Mechan- 
ism^ Kew  York. 

BLAST  HOLES.  A  mi)iing  term.  The  holes  through  which  the  water  enters  the  bot- 
tom of  a  pump  in  the  mines. 

BLEACHING  {Blanchcmcnf,  Fr.  ;  Bleichen,  Germ.)  is  the  process  by  which  the  textile 
filaments,  cotton,  flax,  hemp,  wool,  silk,  and  the  cloths  made  of  them,  as  well  as  various 
vegetable  aiid  animal  substances,  are  deprived  of  their  natural  color,  and  rendered  nearly  or 
altogether  white.  The  term  bleaching  comes  from  the  French  verb  hlanchir,  to  whiten. 
The  word  blanch,  which  has  the  same  oi-igin,  is  applied  to  the  whitening  of  living  plants  by 
causing  them  to  grow  in  the  dark,  as  when  the  stems  of  celery  are  covered  over  with 
mould. 

The  true  theory  of  bleaching  has  not  been  entirely  agreed  upon,  but  there  can  be  little 
doubt  of  the  principal  operations.  It  is  known  that  oxygen  deprives  substances  of  color ; 
this  may  be  performed  by  many  high  oxides  ;  by  nitric  acid,  manganic  and  chromic  acids, 
chlorous  acid,  and  even  lower  oxides  which  liold  their  oxygen  lightly,  as  hypochlorous  acid. 
The  same  effect  may  be  produced  by  chlorine,  bromine,  and  iodine.  It  has  been  said  that 
chlorine  unites  with  the  hydrogen  of  the  water  which  is  present,  gives  off  oxygen,  and  so 
acts  just  as  oxygen  would.  Davy  found  that  it  would  not  act  in  dry  air,  so  that  water  was 
needful :  but  Dr.  "Wilson  found  that  it  would  act,  although  slowly,  in  dry  air,  if  exposed  to 
the  rays  of  the  sun.  This  might  show  that  water  is  not  necessary  in  order  to  supply  oxy- 
gen, but  only  to  allow  the  chlorine  to  be  brought  into  thorough  contact  with  the  coloring 
matter.  It  has  also  been  supposed  that  the  chlorine  removes  the  hydrogen,  or,  rather,  sim- 
ply takes  its  place  by  an  act  of  substitution.  Now,  whether  the  chlorine  or  the  liberated 
oxygen  removes  the  hydrogen,  the  result  will  be  the  same — the  destruction  of  the  com- 
pound. Chlorine  so  readily  performs  these  changes,  that  we  should  at  once  decide  on  call- 
ing it  the  active  agent,  were  it  not  for  the  fact  that  oxygen  acts  so  readily,  even  when 
chlorine  is  not  present :  for  example,  peroxide  of  hydrogen,  as  well  as  the  oxides  just  men- 
tioned, and  ozone  also,  which  has  no  chlorine  to  help  it.  It  is,  then,  certain  that  oxidation 
bleaches  ;  and  it  is  certain  that  dehydration  bleaches,  if  performed  by  chlorine,  and  that  the 
sun  aids  it  by  its  active  rays.  We  know  also  that  water  aids  it :  water  aids  bleaching  or 
oxidation  by  air,  partly  because  it  contains  air  in  solution.  It  aids  also  the  bleaching  per- 
formed by  solutions  in  contact  with  porous  bodies,  because  these  bodies  have  a  power  of 
OGndensing  gases  in  their  pores  and  of  compelling  combinations.  The  next  question  is, 
Does  it  aid  the  bleaching  by  chlorine  in  the  same  way,  by  assisting  the  union  mechanically, 
or  by  decomposing  water?  Chlorine  acts  slowly,  unless  water  be  present.  The  theory, 
therefore,  docs  not  demand  the  decomposition  of  water,  and  the  known  powerful  affinities 
of  chlorine  do  not  require  to  be  supplemented  by  oxygen.  But,  in  order  to  see  exactly  the 
state  of  the  case,  let  us  look  at  the  action  of  chlorine  in  hypochlorites  or  in  chloride  of 
lime,  and  we  find  that  it  is  a  direct  oxidation.  We  obtain  by  it  peroxides  of  metals,  and 
not  chlorides.  Here  we  seem  to  be  taught  directly  by  experiment,  that  bleaching  by  hypo- 
chlorites is  an  oxidation  of  the  coloring  matter.  Bleaching  >)y  moist  chlorine  may  there- 
fore be  looked  on  as  the  same  ;  indeed,  we  oxidize  by  it ;  but  in  such  cases  we  may  obtain  the 
base  at  the  same  time  united  to  chlorine,  giving  another  turn  to  the  question,  as  Kane 
showed.  The  oxidation  theory,  therefore,  seems  to  be  sufficient  when  water  is  present. 
We  are,  however,  finally  to  deal  with  dry  chlorine  in  the  sun  ;  and  in  that  case  it  is  fair  to 
conclude  that  it  acts  by  direct  combination  with  hydrogen  or  the  coloring  matter,  or  both. 
We  have,  then,  two  modes  of  bleaching ;  but  the  usual  mode  in  the  air  becomes  by  that 
explanation  an  oxidation,  and  the  direct  action  of  chlorine  obtainable  only  with  difliculty. 
When  sulphurous  acid  is  used,  another  phenomenon  may  be  looked  for,  as  wc  find  a  sub- 
stance whose  chief  quality  is  that  of  deoxidizing.  The  removal  of  oxygen  also  decomposes 
bodies,  and  sulphuretted  hydrogen  can  scarcely  l)e  supposed  in  act  in  any  other  way.  Sul- 
phurous acid,  when  it  decomposes  sulphuretted  hydrogen,  really  acts  as  an  oxidizing  agent, 
and  we  can  therefore  imagine  it  as  such  in  the  bleaching  process.  Investigation  has  not 
told  us  if  it  enters  into  combination  as  SO^,  and,  like  oxygen,  destroys  color,  altering  the 
compound  by  inserting  itself. 


BLEACHING. 


145 


We  may  fairly  conclude  that  the  processes  by  chlorine  and  sulphurous  acid  are  per- 
formed in  a  manner  as  different  as  the  mode  in  which  a  salt  of  ammonia  acts  on  chlorine  or 
an  oxacid,  or,  in  Dr.  Wilson's  general  terms,  "  Specific  differences  may  be  expected  to 
occur  with  all  the  gases  named,  as  to  their  action  on  any  one  coloring  matter,  and  with 
different  coloring  matters,  as  to  their  deportment  with  any  one  of  the  gases." — Trans.  Ji. 
S.  E.,  18-48. 

It  has  been  attempted  to  introduce  manganates,  chromates,  chlorates,  chlorochroniic 
acid,  and  sulpliites,  but  without  success,  as  bleaching  agents. 

General  Process  of  Bleacldng. — The  process  of  bleaching,  from  what  we  have  seen, 
resolves  itself  into  treatment  with  alkalies  and  the  action  of  chlorine  or  of  light.  In  de- 
scribing the  operations,  they  seem  to  be  very  numerous ;  but,  as  explained,  some  require  to 
be  repeated  gently,  instead  of  being  finished  by  one  decisive  operation,  so  as  not  to  injure 
the  fibre  ;  and  some  are  intermediate  operations,  such  as  the  frequent  washings  needed  in 
passing  from  one  process  to  the  other.  The  alkaline  solution  in  which  the  goods  are  boiled 
does  not  contain  above  250  lbs.  of  carbonate  of  soda  to  600  gallons,  but  nearly  always  less. 
Lime  is,  however,  used  much  more  frequently  than  soda,  which  it  will  be  seen  is  only  em- 
ployed in  tiie  second  process,  and  the  third,  if  there  be  one.  It  is  less  hurtful  to  the  cloth, 
and  is  much  cheaper  than  the  alkalies. 

The  chloride  of  lime  is  used  at  i  Twaddle,  or  1002'5.  It  is  not  considered  so  important 
now  as  formerly,  and  where  300  lbs.  were  formerly  employed,  30  to  40  are  now  used.  The 
goods  are  made  nearly  white  by  the  alkalies.  The  chlorine  gives  only  the  last  finish,  and  is 
sometimes  used  to  whiten  the  ground  on  colored  goods.  The  whole  process  may  be  ex- 
pressed thus : — Wash  out  the  soluble  matter ;  boil  with  lime  to  dissolve  still  more,  and  to 
make  a  fatty  compound  with  the  oily  matter  ;  wash  out  the  lime  by  acids  ;  wash  out  the  fat 
with  a  soda  soap  ;  clear  the  white  by  chloride  of  lime. 

The  impurities  in  the  cloth  have  a  certain  power  of  retaining  color  upon  them.  Mud 
and  dirt,  as  well  as  grease,  gluten,  and  albuminous  matters,  have  this  property,  and  fatty 
soaps,  such  as  lime  compounds  of  fatty  acids.  The  pure  fibre,  however,  has  no  power  of 
taking  up  solutions  of  such  coloring  matter  as  madder.  When,  therefore,  it  is  desired  to 
try  the  extent  to  which  cloth  has  been  bleached,  it  is  dyed  or  boiled  up  with  madder  ex- 
actly as  in  the  process  of  dyeing.  It  is  then  treated  with  soap,  as  the  madder-dyed  goods 
are  treated,  and  if  it  comes  out  without  a  stain,  or  nearly  pure  white,  the  goods  are  ready. 
Dyers  or  calico-printers  who  dye  printed  goods  are  exceedingly  particular  as  to  the  bleach- 
ing, the  dyeing  and  printing  having  now  approached  to  such  exactness,  that  shades  invisible 
to  any  eye  not  very  much  experienced  are  sufficient  to  diminish  in  a  material  degree  the 
value  of  the  cloth.  Any  inequality  from  irregularity  of  bleaching,  which  causes  a  similar 
irregularity  of  dyeing,  is  destructive  to  the  character  of  the  goods.  Many  patterns,  too, 
have  white  grounds ;  these  grounds  it  is  the  pride  of  a  printer  to  have  as  white  as  snow. 
If  delicate  colors  are  to  be  printed,  they  will  be  deteriorated  if  the  ground  on  which  they 
are  to  be  printed  is  not  perfectly  white. 

Old  Method's  still  in  use. — As  a  specimen  of  the  older  processes,  we  shall  give  the  fol- 
lowing, adding  afterwards  a  minute  account  of  some  of  the  plans  adopted  by  the  most  suc- 
cessful bleachers.  When  grease  stains  do  not  exist,  as  happens  with  the  better  kind  of 
muslins,  or  when  goods  were  not  required  to  be  finely  finished,  the  following  has  been 
adopted  : — After  singeing,  1.  Boiling  in  water.  2.  Scouring  by  the  stocks  or  dash-wheel. 
3.  Bucking  with  lime.  4.  The  bleaching  property  so  called,  viz.,  passing  through  chlorine 
or  crofting.  5.  Bucking  or  bowking  with  milk  of  lime.  These  two  latter  processes  em- 
ployed alternately  several  times,  till  the  whole  of  the  coloring  matter  is  removed.  6.  Sour- 
ing.    V.  Washing. 

Tfie  Processes  used  in  Bleaching.  Singcinrj. — The  singeing  is  performed  by  passing 
the  cloth  over  a  red-hot  plate  of  iron  or  copper.  The  figure  50  shows  this  apparatus  as 
improved  by  Mr.  Thom.  At  a  there  is  a  cylinder,  with  the  cloth  wound  round  it  to  be 
singed  ;  it  passes  over  the  red-hot  plate  at  6,  becomes  singed,  passes  over  a  small  roller  at 
c,  which  is  partly  immersed  in  water,  and  by  this  means  has  all  the  sparks  extinguished  ; 
then  is  wound  on  to  the  roller  d,  when  the  process  is  finished.  As  the  products  of  combus- 
tion from  the  singeing  are  sometimes  very  unpleasant,  they  are  carried  l)y  this  apparatus 
into  the  fire-place,  where  they  are  consumed.  The  arrows  .show  the  passage  of  these  vapors 
from  the  surface  of  the  cloth  downwards  into  the  hearth,  and  thence;  into  the  fire. 

For  goods  to  be  finely  printed  both  sides  are  singed  ;  for  market  bleaching,  one  side. 
Sometimes,  however,  singeing  is  not  at  all  desired. 

The  use  of  a  line  of  gas  jets  instead  of  a  red-liot  plate,  was  introduced  by  Mr.  Samuel 
Hall.  It  has  not,  however,  found  its  way  generally  into  bleach  works :  the  plate  is  pre- 
ferred.    Gas  jets  are  used  necessarily  in  singeing  threads. 

Shearing. — For  fine  printing,  it  is  by  some  considered  needful  to  shear  the  nap  of  the 
cloth  instead  of  singeing  it.     The  method  is  more  expensive  tiian  singeing.    Messrs.  Mather 
and  Piatt  have  made  a  machine  which  will  shear  (30  to  80  yards  per  minute. 
Vol.  III.— 10 


146 


BLEACHING. 
60 


BLEACHING. 


147 


Bucking  or  BoioUng. — This  is  the  process  of  boiling  goods.  It  is  perfonned  in  alkaline 
liquids,  generally  lime  or  soda,  or  both.  The  kier  for  bowking  is  a  cylindrical  iron  vessel, 
constructed  so  as  to  render  the  boiling  free,  and  prevent  the  goods  from  being  burnt  on  the 
bottom.  The  kier  of  Messrs.  Mather  and  Piatt  is  very  complete.  The  first  figure  (51)  is 
the  kier  when  shut  or  screwed  down.  The  second  figure  (52)  is  the  section  of  the  tier, 
which  is  very  like  that  before  given ;  but  in  this  case  it  is  steam-tight,  and  heated  by  steam 
which  issues  from  a  steam  pipe  communicating  beneath  the  false  bottom.  The  dangers 
attending  the  kier  before  mentioned  are  by  this  moans  entirely  averted,  and  all  the  inven- 
tions winch  give  the  washing  liquid  a  separate  and  distinct  place  for  heating  are  at  once 
done  away  with. 

An  exact  description  of  these  kiers  is  required,  a,  b,  c,  d,  represent  the  body  of  the 
kier,  which  is  a  cylindrical  vessel,  generally  made  of  cast-iron,  but  sometimes  of  wood,  or 
wrought  iron.  h  represents  false  bottom — a  cast-iron  grating  sometimes  covered  with 
boulder-stones,  and  sometimes  with  wood  ;  </,  cylindrical  disk,  of  wrought  iron,  placed  on 
the  top  of  "  puffer-pipe  "  q,  to  spread  the  liquor  over  the  cloth,  y,  "  puffer-pipe,"  standing 
on  false  bottom,  h.  s,  cylindrical  casting  for  supporting  false  bottom  and  "puffer-pipe," 
whose  periphery  is  "  slotted,"  to  admit  of  the  liquor  passing  through,  r,  cover  for  kier  ; 
the  flanch  on  which  this  cover  rests  is  grooved  a  little,  to  admit  of  "  gasking "  being 
inserted,  so  as  to  form  a  "joint."  k,  k,  swivel  bolts,  holding  down  the  cover,  i,  a  small 
aperture,  covered  with  a  hd  capable  of  being  removed  easily,  to  enable  the  attendant  to  see 
that  the  cloth  does  not  rise  too  high  in  the  kier  to  endanger  its  working  ;  if  such  happens, 
he  checks  the  steam  until  the  cloth  settles,  after  which  it  does  not  again  attempt  to  rise. 
n,  steam  valve ;  I,  water  valve ;  both  communicate  with  pipe  w,  leading  to  kier.  ?%  pipe 
communicating  with  kier  for  supplying  steam  and  water — also  serves  as  escape  pipe  ;  /,  es- 
cape valve  for  letting  off  kier ;  c,  wheel  for  opening  ditto ;  m,  steam  pipe  from  boiler. 
0,  p,  foundation  for  kier.  y 


The  process  of  cleansing  is  very  various.  Some  use  lime  for  the  first  process  ;  some  use 
soda  alone ;  and  some  use  tliem  mixed.  Of  course,  when  carbonate  of  soda  and  lime  are 
used,  caustic  soda  is  at  once  formed,  and  the  carbonate  of  lime  is  left  idle.  The  practices 
and  fancies  of  bleachers  are  numerous  ;  and  we  have  only  to  say  that  the  principle  consists 
in  the  use  of  alkaline  lyes.  Some  use  lime  to  the  amount  of  3  per  cent.  ;  others  go  as  high 
as  10.  The  lime  is  slaked  first  and  a  portion  thrown  in  ;  a  portion  of  cloth  is  laid  upon  it, 
and  a  portion  of  lime  again  covers  that ;  but  on  no  account  nmst  the  goods  be  allowed  to 
lie  in  contact  with  the  atmosphere  and  the  lime. 

When  removed  from  the  kiers  the  goods  must  be  washed.  Now,  if  tlicy  are  to  be 
washed  in  d.xsh-whocls,  it  is  needful  that  they  be  in  separate  pieces,  and  in  this  state  they 
are  sometimes  boiled  in  the  kiers ;  but  if  they  arc  to  be  washed  in  the  wasliiiig  machines, 
they  are  lifted  out  of  the  kier  in  the  same  manner  as  a  piece  of  string  is  drawn  out  of  the 
canister  in  which  the  coil  is  kept. 

M.  Metz,  of  Heidelberg,  has  attempted  to  perform  the  work  of  boiling  by  merely  ex- 
tracting the  air  from  the  cloth.  For  this  purpose  the  cloth  is  sim]>ly  l)ut  into  a  strong 
upright  cylinder,  the  top  screwed  down,  and  the  air  taken  out  by  an  air-i)uiii]).  We  have 
no  knowledge  as  to  the  advantages  gained  by  this  process,  or  whether  it  has  been  found 
actually  capable  of  putting  cloth  in  a  condition  to  be  bleached  for  a  very  fastidious  market. 


148 


BLEACHING. 


'%w^^ww^i^^^w^^^i^^^:j^;;rz3Z~7 


BLEACHING. 


149 


Steeping. — Instead  of  boiling  in  the  kier  at  first,  the  goods  are  sometimes,  though  now 
rarely,  steeped  from  one  to  two  days  in  water,  from  100'  to  150'  F.,  for  the  purpose  of 
loosening  the  gummy,  glutinous,  and  pasty  materials  attached  to  the  cloth.  Fermentation 
ensues,  and  this  process  is  dangerous,  as  the  action  of  the  ferment  sometimes  extends  to  the 
goods,  especially  if  they  are  piled  up  in  a  great  heap  without  being  previously  washed.  The 
spots  of  grease  on  the  insoluble  soaps  become  thereby  capable  of  resisting  the  caustic  alka- 
lies, and  are  rendered  in  some  measure  indelible  :  an  eSect  due,  it  is  believed,  to  the  acetic 
and  carbonic  acids  generated  during  fermentation.  Some  persons  throw  spent  h-es  into  the 
fermenting  vats  to  counteract  the  acids.  The  spots  of  grease  are  chiefly  to  be  found  in 
hand-loom  goods,  and  the  difficulty  concerning  the  fats  is  not  therefore  commonly  felt  where 
power-loom  goods  are  chiefly  used,  as  in  Lancashire. 

Washing. — The  machine  made  by  Mr.  Mather  {figs.  53  and  54)  washes  800  pieces  per 
hour,  or  8,000  pieces  per  day  of  10  hours,  using  400  gallons  per  minute,  or  120,000  gallons 
per  day,  or  20  gallons  to  a  piece.  This  class  of  machine  is  now  in  its  turn  superseding  the 
dash-wheel. 

This  washing  machine  will  be  understood  by  the  general  plan,  {fig.  54,  and  correspond- 
ing section,  fig.  53.)-  a  and  b  represent  the  squeezing-bowls.  a  is  18  inches  diameter  and 
8  feet  3  inches  long  ;  it  is  made  of  deal-timber.  (The  lapping  of  strong  canvas  at  a"  is  for 
the  purpose  of  giving  the  "  out-coming  "  pieces  an  extra  squeeze,  in  order  to  prepare  them 
for  the  kiers.)  b  is  24  Inches  diameter  and  of  the  same  length  as  a,  making  100  revolutions 
per  minute  ;  it  is  generally  made  of  deal,  sycamore,  however,  being  better,  c,  d,  a  strong 
wooden  rail,  in  which  pegs  are  placed  in  order  to  guide  the  cloth  in  its  spiral  form  from  the 
edge  to  the  centre  of  the  machine,  h,  k,  the  water-trough,  through  which  the  piece  passes 
round  the  roller  r.  p,  {fig.  53,)  water-pipe ;  i,  water-tap ;  m,  ?«,  pot-eyes,  which  may  be 
adjusted  to  any  angle,  to  guide  and  regulate  the  tension  of  the  piece  on  entering  the 
machine.  I,  side  frame,  for  carrying  bowls,  &c. ;  g,  engine  (with  cylinder,  8  inches 
diameter)  and  gearing  for  driving  machine  ;  w,  weight'and  lever  for  regulating  pressure  on 
the  bowl. 

This  machine  washes  800  pieces  per  hour,  and  requires  400  gallons  of  water  per  minute. 
It  will  serve  also  to  represent  the  chemick  and  souring  machine,  the  only  difference  being 
that  the  bowls  are  3  feet  6  inches,  instead  of  8  feet  3  inches,  in  length. 

The  chemick  and  sour  are  brought  by  turns  into  the  trough,  or  into  similar  separate 
troughs,  by  a  leaden  pipe  from  the  mixing  cisterns,  and  are  run  in  to  6  or  8  inches  deep. 

The  washing  machine  of  Mr.  Bridson  {fig.  55)  is  worth  attention.  In  its  action  the 
course  of  the  cloth  in  the  water  is  easily  seen ;  it  is  chiefly  horizontal.  This  motion  had 
been  given  by  Hellewell  and  Fearn  in  1856  ;  but  they  had  a  very  complicated  machine,  and 
they  did  not  attain  the  flapping  motion  which  is  given  to  the  cloth  when  it  becomes' sud- 
denly loose,  and  is  driven  violently  against  the  board  a  a  as  often  as  6  c  and  e  d  are  in  one 
line.  It  is  not  shown  by  the  drawing  that  the  cloth  passes  eight  times  round  these  wheels. 
There  is  a  constant  stream  of  water  from  the  pipe  /,  which  is  flattened  at  the  mouth  about 
one  and  a  half  inches  in  one  diameter,  and  about  ten  inches  in  the  other.  This  machine  can 
wash  900  pieces  in  an  hour.  It  requires  about  twice  as  much  water  as  a  dash-wheel  but 
washes  seven  and  a  half  times  more  pieces.     Its  length  is  nine  feet. 

55 


150  BLEACHING. 

Souring. — After  boiling  in  the  first  kier  and  washing,  the  goods  are  soured  in  muriatic 
acid  of  lOlO-  specific  gravity,  or  6^  gallons  of  the  usual  acid,  which  contains  33  per  cent, 
of  real  acid,  mixed  with  100  gallons  of  water.  This  is  equal  to  2°  Tw.  Muriatic  acid  may 
be  replaced  by  sulphuric  acid  of  1024-  specific  gravity,  i.  e.  3|  gallons  liquid  acid  to  lUO 
of  water ; — or  the  amount  of  the  acid  may  be  doubled  in  either  case,  and  a  shorter  time 
allowed  for  the  souring.  The  souring  is  performed  in  wooden  or  stone  cisterns,  where  the 
cloth  is  laid  regularly  as  it  falls  over  one  of  the  rollers  of  the  calender ; — or  it  is  passed 
through  the  acid  solution  by  the  movement  of  the  calender  in  the  same  manner  as  described 
in  the  process  of  washing.  If  this  method  is  used,  it  is  allowed  to  lie  on  the  stillages  from 
two  to  three  hours  to  allow  the  acid  to  act.  The  acid  decomposes  any  lime  soap  formed, 
and  washes  out  the  hme.  Hydrochloric  or  muriatic  acid  has  been  preferred  in  the  process 
described,  as  the  chloride  of  calcium  is  so  much  more  soluble  than  the  sulphate.  After 
souring,  of  course  the  goods  must  be  thoroughly  washed  as  before. 

The  sixth  operation  with  soda  removes  the  remaining  fatty  materials.  If  lime  be  used, 
it  may  be  allowed  to  settle  ;  and  it  is  better  to  allow  it  to  do  so,  and  thus  to  use  pure  caus- 
tic soda,  which  will  with  the  resin  remove  the  impurities  in  a  more  soluble  form.  If,  instead 
of  adding  170  lbs.  of  soda  crystals  to  600  gallons  of  water,  4-6  lbs.  of  liquid  caustic  soda  of 
specific  gravity  1320'  were  added,  the  effect  would  be  the  same. 

The  solution  of  resin  and  carbonate  of  soda  is  a  half-formed  soap,  which  is  considered  to 
act  beneficially  in  moving  the  soluble  matter.  It  would  not  appear,  from  theory,  to  be 
capable  of  doing  so  well  as  the  soda  which  has  its  carbonic  acid  removed  ;  but  tender  goods 
will  not  allow  the  action  of  caustic  soda,  and  the  carbonate  is  therefore  safer. 

Powder-blcachlnrf. — Chloride  of  lime  is  added  in  stone  vessels  where  the  goods  are 
allowed  to  lie.  It  is  universally  called  chemick  in  the  manufactories.  The  strength  used  at 
Brickacre  is  half  a  degree  Twaddle,  or  1002-5.  This  is  sometimes  very  much  increased,  so 
as  to  be  even  5°  in  some  establishments,  according  to  the  goods  bleached  ;  but  it  is  not  safe 
to  allow  the  cloth  to  lie  long  in  such  strong  solutions.  In  such  cases  it  is  needful  to  pass 
them  rapidly  through  with  the  calender,  so  as  to  soak  them  thoroughly,  and  then  to  pass 
them  on  to  the  acid,  and  forward  to  be  washed.  It  may  be  remarked  that  the  use  of  the 
calender  for  these  operations  renders  it  possible  to  use  strong  solutions,  even  for. tender 
goods,  as  there  is  no  time  given  for  injurious  action  on  the  fibre. 

Great  care  is  to  be  taken  to  make  the  solution  of  the  chloride  of  lime  perfectly  clear. 
The  powder  does  not  readily  wet  with  water,  and  it  must  therefore  be  pressed  or  agitated. 
This  may  be  done  by  putting  it  in  a  revolving  barrel  with  water,  until  complete  saturation 
of  the  powder  with  moisture  ;  the  amount  required  is  then  thrown  into  the  cisterns,  and  the 
insoluble  matter  allowed  to  sink.  This  insoluble  matter  must  not  be  allowed  to  come  into 
contact  with  the  cloth,  as  it  will  be  equal  of  course  to  a  concentrated  solution  of  the  liquor, 
and  will  produce  rottenness,  or  burn  the  cloth  so  as  to  leave  holes.  "When  removing  from 
the  trough,  the  cloth  is  drawn  through  squeezing  rollers,  which  press  out  any  excess  of 
chloride  of  lime. 

Squeezing. — A  squeezing  machine,  with  a  small  engine  attached,  is  shown  in  ^17.  56,  for 
the  drawing  of  wliich  we  are  again  indebted  to  the  makers,  Messrs.  Mather  and  Piatt. 

d,  f  represent  the  squeezing  bowls.  They  are  as  large  in  diameter  as  possible,  and  are 
generally  made  of  sycamore  ;  but  the  bottom  one  is  better  made  of  highly  compressed  cot- 
ton, a,  b  arc  the  engine  and  frame  for  driving ;  ^,  frame  for  carrying  bowls ;  /,  /,  com- 
pound levers  for  regulating  the  press  use  ;  s  is  a  screw  for  the  same  purpose,  and  c  is  the 
cloth  passing  through  the  bowls. 

The  white-squeezers,  or  tho.se  used  before  drying,  should  have  a  box,  supplied  with  hot 
water,  fixed  so  that  the  piece  may  pass  through  it  before  going  to  the  nip  of  the  bowl. 

When  the  goods  are  run  through,  they  are  carried  oft'  upon  a  grated  wheelbarrow  in  a 
nearly  dry  state,  and  transferred  to  the  spreading  machine  called  at  Manchester  a  candroji. 
In  many  bleach-works,  however,  the  creased  pieces  are  pulled  straight  by  the  hands  of 
women,  and  are  then  strongly  beat  against  a  wooden  stock  to  smooth  out  the  edges.  This 
being  done,  a  number  of  pieces  are  stitched  endwise  together,  preparatory  to  being  mangled. 
This  squeezing  machine  is  small,  but,  as  will  be  seen,  the  rollers  are  introduced,  so  as  to 
act  as  long  and  as  rapidly  as  cloth  of  whatever  length  is  drawn  through  them. 

The  following  figure  (57)  represents  a  pair  of  squeezers,  for  sciueezing  the  cloth  after 
several  of  the  processes  named,  and  are  shown  as  being  driven  by  a  small  high-pressure 
engine,  a  is  the  fly-wheel  of  engine  ;  6,  crank  of  ditto  ;  c,  frame  of  engine  ;  r/,  spur-wheels 
connecting  the  engine  and  squeezers  ;  e  and/,  sycamore  squeezing  bowls. 

The  cloth  when  passed  over  the  steamed  rollers  is  now  dry ;  but  it  is  not  smooth  and 
ready  for  the  market.  If  the  cloth  is  wanted  for  printing,  no  further  operation  is  needed  ; 
but  if  to  be  sold  a.s  white  calico,  it  is  finished  by  being  starched  and  calendered. 

The  starch  at  large  works  is  prepared  by  the  bleachers  themselves.  At  Messrs.  Bridson's 
it  is  made  with  the  very  greatest  care  from  flour.  Of  course  it  would  be  more  expensive 
for  them  to  buy  it,  as  the  manufacturer  would  dry  it,  and  they  would  recjuire  to  dissolve  it. 
They  arc  able  also,  in  this  manner,  to  obtain  the  purest  starch.     This  is  mixed  with  blue. 


BLEACHTN^G. 


151 


152 


BLEACHING. 


according  to  the  finish  of  the  goods.  A  roller,  which  dips  into  the  starch,  lays  it  regularly 
and  evenly  on  the  cloth  in  the  same  manner  as  mordants  are  communicated  in  calico-print- 
in",  whilst  other  rollers  expel  the  excess  of  the  starch.  The  cloth  is  then  dried  over  warm 
cyTi'ndcrs,  or  by  passing  into  a  heated  apartment.  It  receives  the  final  finish  generally  by 
the  calender  ;  but  muslins  receive  a  peculiar  treatment.    See  Calender,  vol.  i. 

Finishing. — Pure  starch  is  not  always  used  for  the  purpose  of  finishing.  Fine  clay, 
gypsum,  or  Spanish  white,  is  mixed  with  the  cloth  ;  and  if  weight  is  desired  to  be  given, 
sulphate  of  baryta  is  employed.  Mr.  John  Leigh,  of  Manchester,  has  lately  patented  for 
this  purpose  the  use  of  silicate  of  soda,  which,  for  such  goods  as  are  not  injured  by  alkalies, 
seems  to  answer  the  purpose  at  a  very  cheap  rate.  There  can,  however,  be  no  doubt  that 
too  much  attention  is  given  to  this  finish  for  home  goods,  or  for  all  purposes  which  require 
the  goods  to  be  washed  ;  they  assume  a  solidity  of  appearance  which  they  do  not  possess 
when  the  finishing  material  is  removed  from  the  pores,  and  the  cloth  appears  without  dis- 
guise. In  some  instances,  however,  this  finish  is  a  peculiarity  of  the  goods,  and  is  almost  as 
important  as  the  cloth  itself.  P'or  example  :  in  the  case  of  muslins,  when  they  are  dried 
at  perfect  rest,  they  have  a  rigid  inelastic  feeling,  somewhat  allied  to  that  of  thin  laths  of 
wood,  and  feel  very  rough  to  the  touch.  They  are  therefore  dried  by  stretching  the  cloth, 
and  moving  the  lines  of  selvage  backward  and  forward,  so  as  to  cause  the  threads  of  weft  to 
rub  against  each  other,  and  so  as  to  prevent  them  becoming  united  as  one  piece.  Goods 
dried  in  this  manner  have  a  peculiar  spring,  and  such  thick  muslins  are  for  a  time  possessed 
of  great  elasticity.  Several  pieces  folded  up  in  a  parcel  spring  up  from  pressure  like 
caoutchouc. 

Mr.  Ridgeway  Bridson  invented  an  apparatus  for  giving  this  peculiar  finish  to  muslins. 
Formerly  it  was  done  entirely  by  the  hand,  and  in  Scotland  only.  Since  the  invention  of 
this  machine,  this  trade  has  become  a  very  important  one  in  the  Manchester  district. 

Sometimes  goods  are  finished  by  the  beetle,  which  acts  by  repeated  hammering. '  This 
peculiar  action  has  been  transferred  to  a  roller  by  T.  R.  Bridson,  and  called  the  "  Rotatory 
Beetle."  It  consists  of  a  cylinder  having  alternately  raised  and  depressed  surfaces,  and  two 
other  cylinders  which  press'  upon  it,  and  alternately  press  the  cloth  and  give  a  freedom  as  it 
passes  between  the  rollers.  This  is  similar  to  the  rise  and  fall  of  the  hammers  or  mallets 
in  the  beetling  process. 

Sometimes  a  stiff  finish  is  wanted  ;  then  muslins  are  dried  in  the  usual  way. 

Drying. — Figs.  58  and  59  represent  a  drying  machine,  with  eleven  cylinders,  each  22 
inches  in  diameter,  capable  of  drying  1,000  pieces  of  bleached  calico  in  a  day.  a  represents 
cylinders  heated  with  steam  ;  v,  vacuum-valves  in  ditto ;  /,  frame  for  carrying  cylinders ; 
c,  folding  apparatus  ;  s,  steam-pipe  ;  g,  gearing. 


When  goods  arc  dried  having  a  raised  pattern,  such  as  brocades,  or  any  other,  such  as 
striped  white  shirting,  only  one  side  of  the  cloth  is  to  be  exposed  ;  the  pattern  rises  up  from 
the  heated  surfiice  on  which  the  cloth  is  dried.  For  this  reason,  cylinders  such  as  those  just 
described  cannot  be  used.  Large  wheels  of  cast-iron  are  employed,  consisting  of  two  con- 
centric cylinders,  between  which  is  a  closed  space  heated  by  steam.  The  cloth  is  by  this 
means  heated  on  one  side  onlv,  not  passing  from  cylinder  to  cylinder,  in  which  case  the  side 
next  to  the  heating  surface'  would  be  changed  every  time.  The  larger  the  cylinder  or 
wheel,  the  more  rapid  is  the  drying,  as  there  is  more  surface  of  cloth  exposed  to  it  at  a 
time  ;  it  can,  for  the  same  reason,  be  turned  more  rapidly  round.  Well-finished  goods  will 
not  rise  when  heated,  except  on  the  pattern.  Messrs.  Bridson  have  a  large  business  in 
jacconets  for  artificial  flowers  on  account  of  this  peculiar  finish.  They  are  formed  ol  a 
plain  cotton  cloth,  but  stand  the  pressure  of  hot  irons  without  curling. 


BLEACHING. 

69 


153 


No  essential  difference  is  made  in  bleaching  muslins,  except  that  sometimes  weaker 
solutions  are  employed  for  very  tender  goods.  Mr.  Barlow  makes  no  difference  as  a  rule  in 
the  strength  given  in  describing  his  process ;  with  very  strong  goods,  he  sometimes  uses 
the  liquids  stronger. 

It  is  desired  occasionally  to  bleach  goods  which  have  colored  threads  woven  into  them, 
or  colors  printed  on  them.  In  these  cases  great  caution  must  be  used.  It  is  needful  to  use 
weak  solutions,  but  more  especially  not  to  allow  any  one  process  to  be  continued  very  long, 
but  rather  to  repeat  it  often  than  to  lengthen  it.  Tliis  may  be  stated  as  a  general  rule  in 
the  bleaching  of  goods.  It  would  indeed  be  possible  to  do  the  whole  bleaching  in  one 
operation,  but  the  cloth  would  be  rotten.  This  arises  from  the  fact  that,  at  a  certain 
strength,  bleaching  liquid  or  soda  is  able  to  destroy  the  fibre ;  but  another  and  less  strengtli 
does  not  act  on  the  fibre,  but  only  on  such  substances  as  coloring  matters.  This  care  is 
needed  when  printed  goods  which  have  a  white  ground  are  treated.  The  white  ground 
takes  up  color  enough  to  destroy  its  brilliancy,  and  soaping  does  not  always  remove  it.  The 
bleaching  then  is  effected  by  using  bleaching  liquor  at  ^  Twad.  Some  persons  put  a  Turkey 
red  thread  into  the  ends  of  the  pieces.  The  original  use  of  this  seems  to  be  scarcely  known 
among  the  manufacturers.  It  was  used  as  a  test  of  the  mode  of  bleaching  employed.  If 
strong  solutions  be  used,  which  are  apt  to  spoil  the  cloth,  the  color  of  the  dyed  threads  will 
be  discharged.  When  the  separate  system  is  employed,  this  is  evaded  easily ;  it  is  the 
practice  to  keep  the  ends  containing  the  red  threads  out  of  the  liquid,  allowing  them  to  rest 
on  the  side  of  the  vessel. 

Sometimes  chlorate  of  potash  is  used  for  the  same  purpose,  souring  as  with  the  bleaching 
powder.  The  colors  may,  in  this  manner,  be  made  much  more  brilliant  than  before, 
although  a  little  excess  will  discharge  them.  A  good  deal  of  the  effect  may  be  owing  to  the 
better  white  given  to  the  ground.  Besides  these  processes  for  bleaching,  another  was  at 
one  time  introduced,  which  consisted  of  immersing  the  cloth  in  a  solution  of  caustic  alkali, 
and  afterwards  steaming  in  a  close  vessel.  It  is  not  now  in  use.  Alkali  of  1020"  specific 
gravity  was  used. 

The  new  or  continuous  Process. — This  method  owes  its  introduction  to  David  Bentley, 
of  Pendleton,  who  patented  it  in  1828.  It  consists  in  drawing  the  goods  in  one  continuous 
line  through  every  solution  with  which  it  is  desired  to  saturate  them.  This  is  done  by  con- 
necting the  ends  of  all  the  pieces.  The  motion  of  rollers  draws  the  chain  of  clotli  tlius 
formed  in  any  desired  direction,  and  through  any  number  of  solutions  any  given  number  of 
times.     We  shall  allow  him  to  use  his  own  words  : 

Fiff.  60  is  an  end  view  of  two  such  calenders,  each  having  two  larger  rollers  n  and  n  1 , 
a  smaller  driving  roller  c,  two  racks  n  and  d  1,  placed  upon  two  cisterns  g  and  o  1,  inside 
of  which  cisterns  arc  two  rollers  e  and  k  i,  wliich  rollers  have  four  square  ribs  upon  each, 
to  shake  the  goods  as  they  pass  through  the  cisterns.  At  f  is  a  frame  upon  which  the 
batches  of  goods  are  placed  upon  rollers  shown  infu/.  f.l,  where  they  are  marked  k,  k,  k,  k. 
Tiie  calender  cheeks  arc  made  fast  at  the  feet,  at  the  middle,  and  to  the  top  of  the  building, 
having  levers  and  weights  ii  to  give  pressure  to  the  calender  bowls. 

Near  the  end  walls  of  the  building  are  two  rollers,  one  of  which  is  shown  at  a  ;  upon 
eacli  of  these  is  a  .soft  cord  used  as  a  guide  for  conducting  the  goods  througli  the  machinery 
and  cisterns.  The  operation  is  commenced  by  jiassing  one  end  of  the  coi-d  through  the 
rollers  b  and  C,  down  to  cistern  o,  unilcr  roller  k,  through  the  fin-thermost  division  of  rack 
n,  and  again  through  calender  rollers  at  u  and  c,  repeating  the  same,  but  observing  to  keep 


154 


BLEACHING. 


60 


61 


K 


n 


t^ 


the  cord  tight,  and  to  approach  one  division  nearer  in 
rack  D  each  revolution  until  each  division  is  occupied, 
when  the  end  must  pass  over  c,  under  and  around  b  1, 
down  to  and  over  the  guide  roller  i  3,  through  the  nearest 
division  of  rack  d  1  into  cistern  g  1,  under  roller  e  i,  over 
guide  roller  i  2,  and  again  over  roller  c,  under  and  round 
B  1.  This  course  must  be  repeated,  observing  as  bcfoi'e  to 
keep  the  cord  tight,  and  to  receive  one  division  of  rack 
D  1  every  revolution,  until  each  division  of  rack  d  ]  is 
occupied,  when  the  end  must  pass  over  from  b  1  under 
I  4.  The  cord  now  forms  a  sort  of  spiral  worm  round 
and  through  the  machinery  and  cisterns,  beginning  at  b,  c, 
and  ending  at  the  top  of  B  1  to  i  4,  the  number  of  revo- 
lutions being  governed  by  the  number  of  divisions  in  the 
racks  d  and  d  1,  so  that  if  there  were  fifteen  divisions 
in  each  rack,  there  would  be  fifteen  revolutions  under  c, 
round  b  through  g,  under  E  tlirough  d,  and  fifteen  revo- 
lutions over  c  round  n  1,  over  i  3  through  d  1  and  g  1,  un- 
der E  1  over  I  2,  and  again  over  c,  passing  from  the  top  of 
n  1  to  I  4  ;  and  by  this  means,  if  one  end  of  the  back  of  goods  marked  k,  and  placed  upon 
the  frame  f.,  {fig.  61,)  is  fastened  to  the  end  of  the  guide  cord,  the  goods  will,  when  the 
calender  is  put  in  motion,  be  conducted  and  washed  thirty  times  through  the  water  in  the 
cisterns,  and  squeezed  thirty  times  through  the  calenders.  As  the  operation  proceeds  and 
the  guide  cord  passes  through  the  calender,  it  is  wound  by  hand  upon  roller  a  to  prevent  it 
from  becoming  entangled,  and  to  keep  it  in  readiness  for  the  next  operation.  As  soon  as 
the  first  end  of  the  goods  has  passed  through  fig.  61,  and  arrives  at  the  guide  roller  i  4,  it 
is  detached  from  the  end  of  the  guide  cord  and  attached  to  the  guide  cord  to  the  other  end, 
or  with  the  opposite  set  of  calenders.  After  this,  by  putting  these  in  motion,  the  goods  are 
washed  and  squeezed  through  its  cisterns,  which  cisterns  are  supplied  with  hot  and  strong 
lime  lye,  and  the  goods  passing  over  guide  roller  i  9,  they  are  conveyed  over  other  guide 
rollers  to  be  placed  for  the  purpose,  and  taken  down  by  some  person  or  some  proper 
machinery  into  one  of  the  boiling  vessels,  where,  steam  or  fire  heat  being  added,  they  are 
suffered  to  remain  while  the  lime-boiling  takes  effect. 

We  need  not  follow  the  inventor  into  all  the  particulars.  When  the  goods  were  suffi- 
ciently acted  on  by  one  solution,  another  solution  was  used,  so  that  this  mode  of  calender- 
ing not  only  was  a  method  of  moving  the  goods  from  place  to  place  by  means  of  rollers, 
but  it  was  a  method  also  of  saturating  goods  thoroughly  with  a  solution,  and  of  wasliing 
them. 

.  It  was  by  a  similar  method  that  Mr.  Bcntley  bleached  skeins  of  yarn,  of  linen,  or  of  cot- 
ton. The  skeins  are  looped  together  by  tying  any  soft  material  round  the  middle  of  the 
first  skein,  which  will  leave  the  loops  from  one  end  of  the  next  skein  to  pass  half-way 
through,  and  which  will  always  leave  other  two  loops,  and  by  repeating  which  any  quantity 
of  skeins  may  be  looped  together,  tying  the  last  loop  with  another  soft  material. 

The  mode  of  saturating  the  goods  with  solutions  is  effected  by  the  arrangement  shown 


in  fig.  02 
process. 


Rapid  motion  and  frequent  pressure  are  introduced  instead  of  a  still  soaking 


BLEACHING. 

62 


155 


\zr 


-K^T 


c/tK>K^1K^^.^>tt^-^/^Hs^^c_. 


Vyiglll4U.U-.ll  j!}i  .i!!P!'!| 


^u^u. 


W^ 


A  is  a  roller  for  the  guide  cords  ;  b,  e,  b,  are  eleven  washing  rollers  ;  c,  c,  c,  are  speed 
rollers ;  e,  e,  e,  are  twelve  rollers  immersed  in  twelve  divisions  of  the  cistern  G.  The 
eleven  staple-formed  irons  which  pass  through  the  frame  rails  on  each  side  of  the  centres  of 
the  eleven  rollers  b,  b,  b,  and  the  eleven  rollers  c,  c,  c,  serve  to  stay  these  rollers  in  their 
places,  at  the  same  time  allowing  the  eleven  washing  rollers  b,  b,  b,  to  rise  and  fall  accord- 
ing to  the  pressure  by  which  they  are  held  down,  by  the  eleven  weights  attached  to  these 
irons  at  h,  and  upon  the  bottom  rail  may  be  placed  such  staves,  brushes,  or  rollers,  as  may 
be  found  necessary  for  holding  and  brushing  the  goods  in  the  best  manner  to  keep  them 
straight  during  the  different  washings  in  water  and  bleaching  liquors.  The  goods  are  pre- 
pared by  steeping,  as  before  described,  and  placed  in  batches  at  f,  and  passing  under  the 
immersing  rollers  e  and  the  twelve  divisions  of  cistern  g,  between  the  eleven  speed  rollers 
c  and  the  eleven  washing  rollers  b,  as  seen  at  k,  are  taken  down  straight  and  open  into  one 
of  the  vessels,  and  are  then  boiled  by  steam,  which  is  succeeded  by  repeated  washings  alter- 
nately in  water  and  bleaching  liquors,  until  they  are  sufficiently  bleached,  as  before  de- 
scribed. 

The  elevation  and  ground  plan  of  a  bleach-house  and  machinery  capable  of  bleaching 
800  pieces  of  4  lbs.  cloth  per  day,  (for  best  madder  work,)  with  the  labor  of  one  man  and 
three  boys,  Avorking  from  6  until  4  o'clock,  exclusive  of  singeing  and  drying,  arc  represented 
in  figs.  63  and  64,  (p.  156.)  The  letter  d  represents  two  lengths  of  cloth  of  400  pieces  each, 
(end  of  pieces  being  stitched  together  by  patent  sewing  machine  made  by  Mather  and  Piatt,) 
making  together  800  pieces,  passing  through  washing  machine  g,  and  from  thence  delivered 
over  winch,  u\  into  kier,  c, — this  operation  occupies  one  hour, — where  they  are  boiled  for 
twelve  hours  in  lime.  They  are  then  withdrawn  by  the  same  washing  machine,  ff,  washed, 
and  passed  into  second  kier,  b,  (operation  occupying  one  hour,)  where  they  arc  boiled  for 
twelve  hours  in  ashes  and  resin ;  again  withdrawn  by  the  same  machine,  r/,  washed, 
squeezed,  (see  plan  at  u,)  and  passed  over  winch  e,  and  piled  at  A,  (this  operation  occupies 
one  hour.)  They  are  then  taken  from  pile,  h,  and  threaded  through  sour-machine,  e, 
soured,  passed  over  winch,  e",  and  piled  at  k\  (operation,  one  hour,)  where  it  remains  in  the 
pile  for  three  hours.  It  is  then  squeezed  at  c,  and  washed  through  machine,  (f,  (an  hour's 
operation,)  delivered  into  third  kier,  «,  boiled  for  six  hours,  washed  at  ff,  squeezed  at  u,  (an 
hour's  operation,)  and  passed  through  chcmick  machine,  (an  hour'.s  operation,)  and  piled  for 
one  hour ;  after  which  it  is  soured  again,  (an  hour's  operation,)  sciucezed,  and  washed  at  rj, 
(an  hour's  operation,)  squeezed  again  at/,  (an  hour's  operation,)  and  dried  by  machine  at  p, 
{jiff.  63.) 

There  are  several  advantages  in  using  the  squeezing  process  so  often  in  the  above 
arrangement : — Firstly,  The  bowls  of  the  washing  machine  are  not  so  much  damaged  by  the 
heavy  pressure  which  is  required  to  be  applied,  if  no  squeezers  are  used,  in  order  to  prc]iarc 
the  pieces  for  the  sour  and  chemick  machines:  Secondly,  A  drier  state  of  the  cloth  than  cnii 
possibly  be  produced  by  the  washing  machine  alone,  thus  fitting  it  to  become  better  satu- 
rated with  the  chemick  or  sour :  Thirdly,  Tlie  piece  passing  from  the  souring  to  the  washing 
machine,  in  tins  arrangement,  carries  with  it  less  of  the  acid,  and  thus  ensures  a  better 
washing  with  less  water. 

It  may  be  observed,  that  the  velocity  of  the  above-mentioned  macliines  is  nnieh  higher 
than  usual,  experience  having  shown  that  the  various  operations  are  thus  better  performed 


156 


BLEACHING. 


6S 


■■"'///////M/yy-'^- 


C4 


CZJ 


S({UECZERS 


BLEACHING.  157 

than  when  running  slower.  The  reason  of  this  appears  to  be,  firstly,  that  the  piece,  running 
at  such  velocity,  carries  with  it,  by  reason  of  capillary  attraction,  a  greater  quantity  of  liquid 
to  the  nip  of  the  bowls  ;  secondly,  the  great  velocity  of  the  bowls,  together  with  the  greater 
quantity  of  water  carried  up,  produces  a  more  powerful  current  at  the  nip  and  down  the 
ascending  piece,  thus  penetrating  to  every  fibre  of  it. 

It  may  also  be  remarked,  that  the  above-mentioned  machines  are  not  adapted  to  the 
bleaching  of  linen  ;  for  the  latter  cloth,  not  having  the  same  elasticity  as  cotton,  if  it  should 
become  tight,  would  either  be  pulled  narrow  or  torn. 

In  illustration  of  the  continuous  process  as  at  present  used,  tlie  plan  of  proceeding  at 
Messrs.  McXaughten,  Barton,  and  Thorn's,  at  Chorley,  may  be  described : 

1.  In  order  that  there  may  be  no  interruption  in  the  process,  the  pieces  are  united  in 
one  continuous  piece — each  piece  being  about  30  yards,  the  whole  varying  with  the  weight 
of  cloth — about  30i)  yards  long.  Each  piece  is  marked  with  the  name  of  the  printer.  This 
is  sometimes  done  in  marking  ink  of  silver,  and  sometimes  in  coal  tar,  at  the  extremity  of 
the  piece.  The  pieces  are  rapidly  tacked  together  by  girls,  who  use  in  some  establishments 
a  very  simple  sewing  machine.  (See  Sewing  Machine.)  The  whole  amount  to  be  bleached 
at  a  time  is  united  in  one  piece,  and  is  drawn  from  place  to  place  like  a  rope.  To  give 
them  this  rope  form,  the  goods  are  drawn  through  an  aperture  whose  surface  is  exceedingly 
smooth,  being  generally  of  glass  or  earthenware.  Of  these  many  are  used  in  transferring 
the  cloth  from  place  to  place.  They  serve  instead  of  pulleys.  The  cloth  when  laid  in  a 
vessel  is  not  thrown  in  at  random,  but  laid  down  in  a  carefully  made  coil.  The  rope  form 
enables  the  water  to  penetrate  it  more  easily. 

2.  The  pieces  are  singed. 

3.  They  are  boiled  in  the  first  kier.  In  this,  3,500  lbs.  of  cloth  have  added  to  them 
250  lbs.  of  caustic  lime,  1  lb.  of  lime  to  14  of  cloth.  The  kier  is  cylindrical,  7  feet  deep 
and  8  feet  in  diameter ;  as  much  water  is  added  as  will  cover  the  cloth,  about  500  gallons. 
This  boiling  lasts  thirteen  hours. 

4.  They  are  washed  in  the  washing  machine.  Robinson  and  Young's  machine  is 
used. 

5.  They  are  soured  in  a  similar  machine  with  hydrochloric  acid  of  specific  gravity  1010', 
or  2"  of  Twaddle. 

6.  The  same  amount  of  cloth  being  supposed  to  be  used,  it  is  bucked  in  a  solution  of 
soda-ash  and  resin,  170  lbs.  of  soda-ash  to  30  lbs.  of  resin.  The  boiling  lasts  sixteen  hours, 
the  same  amount  of  water  being  used. 

7.  Washed  as  before. 

8.  Passed  through  chloride  of  lime,  or  chemicked.  The  cloth  is  laid  in  a  stone  or 
wooden  cistern,  and  a  solution  of  bleaching  powder  is  passed  through  it,  by  being  poured 
over  it  and  allowed  to  run  into  a  vessel  below ;  this  is  managed  by  continued  pumping. 
This  solution  is  about  half  a  degree  Twaddle,  or  specific  gravity  1002-5.  The  cloth  lies  in 
it  from  one  to  two  hours. 

.     9.  Washed. 

10.  Boiled  again  in  a  kier  for  five  hours  with  100  lbs.  of  carbonate  of  soda  crystals. 

11.  Washed. 

12.  Put  in  chloride  of  lime  as  before. 

13.  Soured,  in  hydrochloric  acid  of  1012-5  specific  gravity,  or  2.^°  Twaddle. 

14.  Lies  six  hours  on  stillages. — A  stillage  is  a  kind  of  low  stool  used  to  protect  the 
cloth  from  the  floor. 

15.  Washed  till  clean. 

16.  Squeezed  in  rollers. 

17.  Dried  crver  tin  cylinders  heated  by  steam. 

This  is  the  process  for  calico  generally  ;  some  light  goods  must  be  more  carefully  handled. 
The  usual  time  occupied  by  all  these  processes  is  five  days.  They  are  sometimes  dried 
in  a  hydro-extractor ;  after  singeing,  laid  twenty-four  hours  to  steep,  then  washed  before 
being  put  into  the  lime  kier. 

High-pressure  Steam  Kier. — This  is  designed  still  further  to  hasten  the  process  of 
bleaching,  and  at  the  same  time  to  improve  it. 

Fig.  65  is  an  elevation  showing  the  arrangement  of  these  kiers,  (which  are  ia?comnicnded 
to  be  made  of  strong  boiler-plate  iron.)  One  of  these  is  shown  in  section,  a  and  b  are  the 
kiers  ;  c  is  a  perforated  platform,  on  which  the  goods  to  be  bowked  are  laid  ;  k  k  is  the  pijic 
connecting  the  bottom  of  the  kier  h  with  the  top  of  the  adjoining  kier,  a  ;  and  /,  /,  the 
corresponding  pipe  coimecting  the  opp(jsite  ends  of  the  kiers  a  and  h  ;  vi  in  are  draw-olf 
cocks,  connected  with  the  pipes  k  and  /,  l)y*which  the  kiers  can  be  emi)ticd  of  spent  liquor, 
water,  &c.  ;  n  and  o  are  ordinary  two-way  taps,  I)y  which  the  steam  is  admitted  into  tlie 
respective  kiers  from  the  main  pijjc,  ;>,  and  the  reversing  of  which  shuts  off  tlie  steam  com- 
munication, and  admits  the  bowking  \u\\n)v  .as  it  becomes  expelled  from  the  adjoining  kier ; 
</  is  a  blowing-off  valve  or  tap  ;  r,  the  pipe  through  which  the  bowking  liquor  enters  into 
the  kier;  s,  manhole,  (closed  by  two  cross  bars,  secured  by  bolts  and  nuts,)  through  which 


158 


BLEACHING. 
65 


the  floods  arc  introduced  and  removed  ;  ^  <  are  gauges,  by  which  it  is  ascertained  when  th« 
liquor  has  passed  from  one  kier  and  has  entered  the  other. 

The  process  adopted  for  bleaching  is  as  follows ;  it  is  the  shortest  and  simplest  in  use :  • 

1.  The  box  or  water  trough  of  the  washing  machine  is  then  half  filled  with  milk  of  lime 
of  considerable  consistence,  and  the  goods  are  run  through  it,  being  carried  forward  by  the 
winches  and  deposited  in  the  kicrs.  Tiic  whole  of  the  cloth  in  a  kier  is  in  one  length,  and 
a  boy  enters  the  vessel  to  lay  it  in  regular  folds  until  the  kier  is  filled.  All  the  doth  before 
entering  the  kier  must  pass  through  tlie  lime. 

2.  When  the  kiers  are  filled,  a  grid  of  movable  bars  is  laid  on  the  top  of  the  cloth,  and 
the  manhole  of  the  kiers  is  closed.  High-pressure  steam  is  then  admitted  at  the  top  ;  this 
presses  down  the  goods  and  removes  the  lime  water,  which  is  drawn  oft"  at  the  bottom.  At 
the  same  time  the  air  is  also  removed  from  the  goods  and  replaced  by  steam.  When  this  is 
driven  off,  and  nothing  but  steam  issues  from  the  tap  at  the  bottom,  40  lbs.  of  lime,  which 
have  been  previously  mixed  with  000  gallons  of  water,  are  introduced  into  the  first  kier  in 
a  boiling  state.  Iligh-pressurc  steam  is  again  admitted,  which  forces  the  lime  litiuor 
through  the  goosls  to  the  bottom  of  the  vessel,  then  up  the  tube  /,  and  on  to  the  goods  in 
the  second  kier.  The  tap  is  then  closed  which  admits  steam  into  the  first  kier,  and  the 
steam  is  now  sent  into  the  second.  The  same  process  occurs,  only  in  this  case  the  liquid  is 
sent  again  on  to  the  top  of  the  goods  in  the  first  kier.  This  process  is  continued  about 
eight  hours. 

In  this  method  each  7,000  lbs.  of  cloth  take  into  the  kiers  2  cwts.  of  lime,  which  is 
etiually  distributed.  The  clear  lime-water  which  is  blown  out  of  the  steam  at  the  com- 
mencement contains  only  3  to  4  lbs.  of  lime  in  solution.  At  the  close  of  tlic  operation  the 
liquor  has  a  specific  gravity  of  3|  to  4'  Twaddle,  (lOlY'D  to  1020,)  instead  of  half  that 
amount,  or  1^  to  2^  Twad.,  (1007-5  to  1010,)  as  is  usual. 

3.  When  the  liming  is  completed  the  steam  pressure  in  the  kiers  is  removed,  the  man- 
way  opened,  the  grid  lying  above  the  cloth  removed,  and  the  cloth  in  the  kier  attached  to 
the  washing  machine,  which  draws  the  goods  out  of  the  kicrs  and  washes  them. 

4.  The  pieces  are  then  passed  by  the  winches  through  the  souring  machine,  or  soured 


BLEACHING.  159 

by  having  muriatic  acid  of  2°  Twaddle  pumped  upon  them,  (1010.)     They  must  remain 
with  the  acid  two  or  three  hours,  either  steeped  in  it,  or  after  having  passed  through  it. 

5.  Again  attach  the  cloth  to  the  wasliiiig  machine,  and  wash  it  well,  passing  it  on  by 
winches,  as  before,  into  the  kier. 

6.  Introduce  steam  and  drive  off  the  air  and  the  cold  water ;  these  are  let  out  by  the 
tap  at  the  bottom:  add  then  22-1  lbs.  of  soda-ash  and  150  lbs.  of  resin,  boiled  in  600 
gallons  of  water,  for  7,000  lbs  of  cloth.  Work  the  kiers  by  driving  the  liquid  from  one  to 
the  other  as  before  ;  about  eight  hours  is  a  sufficient  time.  These  proportions  of  soda  may 
he  varied.  If  the  clotli  is  very  strong,  a  little  more  may  be  used,  (or  if  the  cloth  has  been 
printed  upon  in  the  gray  state,  from  having  been  used  to  cover  the  blanket  of  the  calico- 
printing  machine.) 

7.  After  this  the  cloth  is  passed  through  the  washing  machine,  and  then  submitted  to 
chloride  of  lime.  This  may  be  done  either  by  the  machine  or  by  pumping.  In  either  case 
it  is  an  advantage  to  warna  the  bleaching  liquid  up  to  80°  or  9i)°  F.  The  strength  of  the 
solution  when  the  machine  is  used  maybe  about  -k"  Twaddle,  or  1002-5  specific  gravity ; 
but  if  the  pump  is  used  it  must  be  much  weaker.  When  the  bleaching  is  for  finishing 
white,  milk  of  lime  is  added  to  the  chloride,  in  order  to  retard  the  operation ;  the  goods 
are  also  washed  from  the  bleaching  liquor  before  souring  them.  This  causes  a  similar 
escape  of  chlorine,  and  is  a  more  careful  method  ;  it  tends  to  preserve  the  headings,  or  the 
colored  threads,  which  are  often  put  into  the  ends  of  pieces  of  cloth  in  order  to  see  if  the 
bleaching  has  been  performed  roughly  or  not.  The  original  use  of  this  has  almost  been 
forgotten,  but  these  headings  are  still  carefully  preserved.  This  method  preserves  also  the 
cloth,  which  is  also  less  apt  to  be  attacked  by  the  chlorine. 

If  the  cloth  has  been  well  managed,  it  will  be  almost  white  when  it  leaves  the  second 
kier  containing  the  resinate  of  soda  ;  it  will  therefore  require  very  little  decolorizing.  If 
the  goods  have  been  printed  on,  more  chloride  will  be  needed.  The  cloth  should  lie  from 
two  to  eight  hours  in  the  liquor,  or  after  saturation  with  it.  The  action  is  quickened  if 
warmth  is  used.  They  are  soured  then,  as  before,  in  muriatic  and  sulphuric  acid,  at  2' 
Tw.,  for  three  or  four  hours  ;  then  wash  for  drying. 

This  method  of  Mr.  Barlow's  is  an  undoubted  shortening  of  the  process  of  bleaching ; 
eight  hours  only  of  bucking  are  found  to  be  enough,  and  the  whole  may  be  performed,  by 
the  help  of  the  continuous  system,  in  two  days.  It  will  be  seen  that  the  steam  drives  the 
solution  through  the  cloth  ;  and  this  is  equal  to  the  process  of  stirring,  which  is  a  continual 
change  of  surface  and  of  liquid,  but  it  is  more  effectual  than  any  stirring  could  possibly  be. 
The  goods  are  laid  in  a  firm,  compact  mass,  and  held  down  by  an  iron  grid,  so  that  the 
liquid  cannot  run  through  ruts  and  crevices,  but  must  run  through  the  cloth  itself. 

From  what  has  been  said,  it  will  be  seen  that  the  operations  of  the  bleacher  are  not  so 
numerous  as  at  first  sight  appears,  when  we  call  every  washing  a  separate  process ;  and 
although  it  really  is  so,  it  is  managed  so  rapidly  that  it  can  scarcely  be  said  to  occupy  time, 
and  as  it  is  carried  on  at  the  same  time  as  the  other  processes,  it  scarcely  can  be  said  to  give 
trouble.     The  work  may  be  divided  into  : — 

1.  Singeing. 

2.  Bowking  with  lime. 

3.  Washing,  souring,  and  washing. 

4.  Bowking  with  resinate  of  soda. 

5.  Washing  and  chlorinating. 

6.  Souring,  washing,  and  drying. 

This  process  has  been  tried  with  success  on  linen,  although  not  yet  in  active  operation. 

Bleaching  of  Linen. 
Old  Method. — What  is  called  the  old  method,  or  that  used  from  about  the  introduction 
of  bleaching  powder,  at  the  beginning  of  the  century,  till  within  ten  or  fifteen  years,  re- 
quired bleaching  on  the  grass  ;   and  the  mode  in  which  it  was  managed  in  Ireland  and  Scot- 
land, where  it  held  its  ground  longest,  is  as  follows  : — 

1.  They  were  rot-steeped  in  a  weak  solution  of  potash,  at  about  130°  F.,  for  two  days, 
until  the  dressing  used  in  manufacturing  the  cloth  was  removed. 

2.  Washed. 

3.  Boiled  or  bowked  in  potash  lye,  at  |°  Twaddle,  for  ten  hours. 

4.  Washed,  and  the  ends  turned  so  that  the  whole  might  be  equally  exposed  to  the  lye. 

5.  Boiled  or  bowked  in  a  similar  lye  to  the  above  for  twelve  hours. 

6.  Washed  well. 

7.  Exposed  on  the  grass  for  three  days,  and  watered. 

8.  Taken  up  and  soured  with  sul])huric  acid,  at  2°  Tw.,  for  four  hours. 
0.  Taken  up  and  washed  well. 

10.  Roiled  again  for  eight  hours  in  potash  lye,  at  1"  Tw.,  to  which  had  been  added  black 
or  soft  soap,  about  2(J  lbs.  to  a  kier  of  about  300  gallons. 

11.  Washed. 


160  BLEACHING. 

1 2.  Crofted,  or  exposed  on  the  grass,  as  before. 

13.  Treated  with  chloride  of  lime  at  1^°  Tw.,  for  four  hours. 

14.  Washed. 

15.  Soured  in  sulphuric  acid,  at  2°  Tw.,  for  four  hours. 

16.  Washed. 

1 7.  Boiled  for  six  or  seven  hours  with  soap  and  lye,  using  in  this  case  more  soap  and 
one-third  less  lye  than  in  the  former  bowkings. 

18.  Drawn  out  and  put  through  rub-boards.  This  is  a  kind  of  washing  machine,  made 
of  blocks  of  wood,  with  hard-wood  teeth.  The  goods  are  washed  by  it  in  a  soapy  liquid. 
The  teeth,  moving  rapidly,  drive  the  soap  into  the  cloth. 

19.  Boiled  in  the  lye  alone  for  six  hours. 

20.  Washed. 

21.  Crofted,  keeping  them  very  clean,  as  this  is  the  last  exposure. 

22.  Treated  with  chloride  of  lime. 

23.  They  are  then  starched,  blued,  and  beetled,  to  finish  them  for  the  market.  These 
operations  last  six  weeks. 

A'ew  Si/sicm,   as  practised  in  Scotland  and  Ireland. — Directions  given  hy  an  extensive 

Bleacher. 

1.  Wash. 

2.  Boil  in  lime-water  ten  or  twelve  hours. 

3.  Sour  in  muriatic  acid,  of  2'  Tw.,  for  three,  four,  or  five  hours. 

4.  Wash  well. 

5.  Boil  with  resin  and  soda-ash  twelve  hours. 

G.  Turn  the  goods,  so  that  those  at  the  top  shall  be  at  the  botom,  and  boil  again  as  at 
Xo.  5. 

7.  Wash  well. 

8.  Chemick,  at  ^°  Tw.,  or  1002-5,  four  hours. 

9.  Sour,  at  2"'  Tw.,  or  lUlO'  specific  gravity. 

10.  Wash. 

11.  Boil  in  soda-ash  ten  hours. 

12.  Chemick  again. 

13.  Wash  and  dry. 

This  is  the  system  chiefly  adopted  when  the  goods  are  to  be  printed. 
The  following  is  the  system  practised  in  the  neighborhood  of  Perth,  where  the  chief 
trade  is  in  plain  sheetings  : — 

1.  Before  putting  them  into  operation,  they  are  put  up  into  parcels  of  about  35  cwts. 

2.  They  are  then  steeped  in  lye  for  twenty-four  hours. 

3.  Then  washed  and  spread  on  the  grass  for  about  two  days. 

4.  Boiled  in  lime-water. 

5.  Turned,  and  boiled  again  in  lime-water,  those  at  the  top  being  put  at  the  bottom. 
GO  lbs.  of  lime  are  used  at  a  time,  and  about  GoO  gallons  of  water. 

G.  Washed,  then  soured  in  sulphuric  acid  of  2"  Tw.,  or  lOlQ-  sp.  gr.,  for  four  hours, 
then  washed  again. 

7.  Boiled  with  soda-ash  for  ten  hours ;  110  lbs.  used. 

8.  Washed  and  spread  out  on  the  green,  or  crofted. 

9.  Boiled  again  in  soda  as  before.  .  . 

10.  Crofted  for  three  days. 

ir.  They  are  then  examined  :  the  white  ones  are  taken  out ;  those  that  are  not  finished 
are  boiled  and  crofted  again. 

12.  Next,  they  are  scalded  in  water  containing  80  lbs  of  sod.a-ash,  and  washed. 

13.  The  chloride  of  lime  is  then  used  at  t^°  Tw.,  or  1002-5  specific  gravity. 

14.  Wa.shed  and  scalded. 

15.  Wa.shed  and  treated  with  chloride  of  lime. 

16.  Soured,  for  four  hours,  with  sulphuric  acid,  at  2°  Tw.,  or  1010'  specific  gravity. 

17.  Washed. 

If  cloths  lighter  than  sheetings  are  used,  the  washing  liquids  are  used  weaker.  The 
great  point  is  to  observe  them  carefully  during  the  process,  in  order  to  see  what  treatment 
will  suit  them  best. 

It  will  he  seen  that  the  process  of  bleaching  linen  is  still  very  tedious ;  and  although  it 
may  be  managed  in  a  fortnight,  it  is  seldom  tliat  this  occurs  regularly  for  a  great  length  of 
time.  The  .iction  of  the  light  introduces  at  once  an  uncertain  element,  as  this  varies  so 
much  in  our  climate.  If,  again,  linen  be  long  exposed  to  the  air  in  a  moist  condition,  it  is 
apt  to  become  injured  in  strength.  To  shorten  the  process,  therefore,  is  important ;  and 
if  no  injurious  agents  are  introduced,  a  shortening  promises  also  to  give  increased  strength 
to  the  fibre.  It  has  not  beon  found  possible  to  introduce  chlorine  into  linen  bleaching  at  an 
early  stage,  as  in  the  case  of  cotton  ;  and  the  processes  for  purifying  it  without  any  chlorine 
render  it  so  white  that  unskilled  persons  would  call  it  as  white  as  snow.     The  chlorine  is 


BLEACHING. 


IGl 


introduced  nearly  at  the  end  of  the  operation,  after  a  scries  of  boilings  with  alkalies,  sour- 
ings,  and  exposures  on  the  grass.  If  introduced  at  an  earlier  stage,  the  color  of  the  raw 
cloth  becomes  fixed,  and  cannot  be  removed.  The  technical  term  for  this  condition  is 
"  isei."  Mr.  F.  M.  Jennings,  of  Corli,  has  just  patented  a  method  which  promises  to  obviate 
the  difficulty.  The  peculiarity  consists  in  using  the  alkali  and  the  chloride  of  alkali  at  the 
same  moment,  thus  giving  the  alkali  opportunity  to  seize  on  the  coloring  matter  as  soon  as 
the  chloride  has  acted,  and  thereby  preventing  the  formation  of  an  insoluble  compound. 
He  prefers  the  chlorides  of  potash  or  soda.     His  plan  is  as  follows  : — 

1.  He  soaks  the  linen  in  water  for  about  twelve  hours,  or  boils  it  in  lime  or  alkali,  or 
alkali  with  lime,  and  then  soaks  it  in  acid,  as  he  uses  soaps  of  resin  in  other  mixtures — the 
alkalies  being  from  3'  to  5°  Tw.,  Inl5--1025'  specific  gravity. 

2.  Boils  in  a  similar  alkaline  solution. 

3.  Washes. 

4.  Puts  it  into  a  solution  of  soda,  of  5"  Tw.,  1025-  specific  gravity,  adding  chloride  of 
soda  until  it  rises  up  to  from  6°-7''  Tw.  It  is  allowed  to  remain  in  this  solution  for  some 
hours,  and  it  is  better  if  subjected  to  heating  or  squeezing  between  rollers,  as  in  the  wash- 
ing machine. 

5.  He  then  soaks,  sours,  and  washes. 

6.  He  then  puts  it  a  second  time  into  the  solution  of  alkali  and  chloride. 

1.  Then  washes,  and  boils  again  with  soda.  These  operations,  6  and  7,  may  be  repeated 
until  the  cloth  becomes  almost  white. 

The  amount  of  exposure  on  the  grass  by  this  process  is  said  to  be  not  more  than  from 
one-half  to  one-fourth  that  required  by  the  usual  method,  or  it  may  be  managed  so  as  en- 
tirely to  supersede  crofting. 

Chevalier  Clausen  has  opened  up  the  filaments  of  flax  by  the  evolution  of  gas  from  a 
carbonate  in  which  the  plant  is  steeped,  and  at  the  same  time  bleached  by  chloride  of  mag- 
nesia. 

Bleaching  of  Materials  for  Paper. 

The  bleaching  of  paper  is  conducted  on  the  same  principle  as  the  bleaching  of  cotton. 
Paper  is  made  principally  of  two  materials,  cotton  and  flax,  generally  mixed.  The  cotton 
waste  of  the  mills,  which  is  that  inferior  portion  which  has  become  too  impure  for  spinning, 
or  otherwise  deteriorated,  and  cotton  rags,  are  the  principal,  if  not  the  only,  sources  of  the 
cotton  used  by  paper-makers.  The  waste  is  sorted  by  hand,  the  hard  and  soft  being  sepa- 
rated, and  all  accidental  mixtures  which  occur  in  it  are  removed.  This  is  done  at  first 
roughly  on  a  large  lattice,  which  is  a  frame  of  wire  cloth,  having  squares  of  about  three- 
quarters  of  an  inch  through  which  impurities  may  fall.  It  is  then  put  into  a  duster,  which 
is  a  long  rectangular  box,  it  may  be  ten  feet  long,  lying  horizontally,  the  inside  diameter 
about  two  feet,  and  covered  with  wire  gratings  running  horizontally,  leaving  openings  of 
half  an  inch  in  width.  As  this  revolves,  the  waste  is  thrown  from  one  angle  to  the  other, 
and  throws  out  whatever  dust  or  other  material  falls  into  the  holes  or  spaces.  The  fibrous 
matter  has  little  tendency  to  separate  from  the  mass,  which  is  somewhat  agglutinated  by 
being  damp,  chiefly  from  the  oil  obtained  during  the  processes  in  the  cotton  mill.  A  second 
duster,  however,  is  used  to  retain  whatever  may  be  of  value  ;  it  is  a  kind  of  riddle.  It  is 
then  transferred  to  the  lattices,  which  are  a  series  of  boxes  covered  with  wire  gauze,  the 
meshes  of  which  are  about  half  an  inch  square,  and  so  arranged  as  to  form  a  series  of  sort- 
ing tables.  The  sorting  generally  is  done  by  young  women.  Each  table  has  a  large  box  or 
basket  beside  it,  into  which  the  sorted  material  is  thrown  ;  this  is  removed  when  filled,  by 
being  pushed  along  a  railroad  or  tramway.  Pieces  of  stone,  clay,  leather,  wood,  nails,  and 
other  articles,  are  taken  out.  The  cotton  is  then  put  into  a  devil  similar  to  that  which  is 
used  in  cotton  machinery,  but  having  larger,  stronger  teeth,  which  tear  it  up  into  small 
fragments. 

The  rags  are  sorted  according  to  quality,  woollen  carefully  removed,  and  all  the  unavail- 
able material  sent  back  to  the  buyer.  They  are  then  chopped  up  by  a  knife,  on  the  circum- 
ference of  a  heavy  wheel,. into  pieces  of  an  inch  wide,  devilled,  and  dusted. 

The  rags  and  the  cotton  waste  are  bleached  in  a  similar  manner.  The  cotton  is  put  into 
kiers  of  about  ten  feet  in  diameter,  of  a  kind  similar  to  those  described,  and  boiled  with 
lime.  The  amount  of  lime  used  is  about  6  lbs.  to  a  cwt.  of  cotton  or  rags,  but  this  varies 
according  to  the  impurity.  The  lime  removes  a  great  amount  of  impure  organic  matter, 
and,  as  in  bleaching,  cotton  cloth  lays  hold  of  the  fatty  matter,  of  which  there  is  a  great 
deal  in  the  waste.  When  taken  out,  it  is  allowed  to  lie  from  two  to  three  hours.  The  ap- 
pearance is  not  much  altered  ;  it  appears  as  impure  as  ever. 

It  is  then  put  into  the  rag-engine  and  washed  clean.  This  ia^a  combined  washing  ma- 
chine and  filter,  the  invention  of  Mr.  Wrigley,  near  Bury.  The  washing  may  last  an  hour 
and  a  half,  or  more. 

The  cotton  has  now  a  brii;ht  gray  color,  and  looks  moderately  clean.     It  is  full  of  water, 
which  is  removed  by  a  hydraulic  press,  the  cotton  being  put  into  an  iron  cylindrical  box  with 
perforated  sides.     It  is  then  boiled  in  kiers  or  puffing  boilers,  where  soda-a^sh  is  used,  at  the 
Vol.  III.— 11 


162 


BLEAK. 


rate  of  4  to  5  lbs.  a  cwt.  Only  as  much  water  is  used  as  will  moisten  the  goods  thoroughly. 
Much  water  would  weaken  the  solution  and  render  more  soda  necessary.  It  is  then  washed 
a^rain  in  the  rag-engine  ;  afterwards  put  into  chloride  of  lime,  acidified  as  in  cotton  bleach- 
ing, and  washed  again  in  the  rag-engine. 

The  cotton  rags  are  treated  in  a  similar  manner.  The  colored  rags  are  treated  sepa- 
rately, requiring  a  different  treatment  according  to  the  amount  of  color  ;  this  consists  chiefly 
in  a  greater  use  of  chloride  of  lime. 

Some  points  relating  to  bleaching  are  necessarily  treated  of  under  Calico  Printing. 

BLEAK.  (Ci/prinus  Alburnus.)  The  scales  of  this  fish  are  used  for  making  the 
essence  of  pearl,  or  essence  (Torient,  with  which  artificial  pearls  are  manufactured.  In  the 
scales  of  the  fish  the  optical  eflect  is  produced  in  the  same  manner  as  in  the  real  pearl,  the 
grooves  of  the  latter  being  represented  by  the  inequalities  formed  by  the  margins  of  the 
concentric  lamina;  of  which  the  scales  are  composed.  These  fish  are  caught  in  the  Seine, 
the  Loire,  the  Saone,  the  Rhine,  and  several  other  rivers.  They  are  about  four  inches  in 
length,  and  are  sold  very  cheap  after  the  scales  are  washed  off.  It  is  said  that  4,000  fish 
are  necessary  for  the  production  of  a  pound  of  scales,  for  which  the  fishermen  of  the  Cha- 
lonnois  get  from  18  to  25  livres. 

The  pearl  essence  is  obtained  merely  by  well  washing  the  scales  which  have  been  scraped 
from  the  fish  in  water,  so  as  to  free  them  from  the  blood  and  mucilaginous  matter  of  the 
fish. 

BLEXDE  (sulphide  or  sulphuret  of  zinc,  "  Black  Jack  ")  is  a  common  ore  of  zinc,  com- 
posed of  zinc  07,  sulphur  33  ;  but  it  usually  contains  a  certain  proportion  of  the  sulphide 
of  iron,  which  imparts  to  it  a  dark  color,  whence  the  name  of  "  Black  Jack,"  applied  to  it 
by  the  Cornish  miner.  The  ore  of  this  country  generally  consists  of  zinc  61 '5,  iron  4m >, 
sulphur  33'0.  Blende  occurs  either  in  a  botryoidal  form  or  in  crystals,  (often  of  very  com- 
plex forms,)  belonging  to  the  tctrahedal  division  of  the  monometric  system.  H  =  3-5  to  4. 
Specific  gravity  =  3"9  to  4. — H.  W.  B. 

In  some  districts  the  presence  of  the  sulphide  of  zinc  is  regarded  by  the  miners  as  a 
favorable  indication,  hence  we  have  the  phrase,  "'Black  Jack  rides  a  good  horse."  In  other 
localities  it  is  thought  to  be  equally  unfavorable,  and  the  miners  say,  "  Black  Jack  cuts  out 
the  ore."  For  many  years  the  English  zinc  ores  were  of  little  value,  the  immense  quantity 
of  zinc  manufactured  by  the  Yieille  Montagne  Company,  and  sent  into  this  country,  being 
quite  sufficient  to  meet  the  demand.  Beyond  this,  there  was  some  difficulty  in  obtaining 
zinc  which  would  roll  into  sheets,  from  the  EngHsh  sulphides.  Although  this  has  been  to 
some  extent  overcome,  most  of  the  zinc  obtained  from  blende  is  used  in  the  manufacture 
of  brass. 

Dana  has  given  the  following  analyses  of  varieties  of  blende  : — 


Sulptur. 

Zinc. 

Iron. 

Cadmium. 

Carinthia 

New  Hampshire 

New  Jersey    -         -         - 

Tuscany 

32-10 
32-  6 
32-22 
82-12 

64-22 
52-00 
67-46 
48-11 

1-32 
10-0 

11-44 

trace 

3-2 
trace 

1-23 

BLIND  COAL,  a  name  given  to  Anthracite. 

BLOCK  TIN.  Metallic  tin  cast  into  a  block,  the  weight  of  which  is  now  about  3^ 
cwts.  Formerly,  when  it  was  the  custom  to  carry  the  blocks  of  tin  on  the  backs  of  mules, 
the  block  was  regulated  by  what  was  then  considered  to  be  a  load  for  the  mule,  at  2J  cwts. 
Subsequently,  the  block  of  tin  was  increased  in  size,  and  made  as  much  as  two  men  could 
lift,  or  3  cwts.  It  was  the  custom  to  order  so  many  blocks  of  tin,  and  the  smelter,  being 
desirous  of  selling  as  much  tin  as  possit)le,  continued  to  increase  the  size  of  the  block,  so 
that,  although  ^^  cwts.  is  the  usual  weight,  many  blocks  are  sold  weighing  3f  cwts. 

BLOOD.  Mr.  Pillans,  in  1854,  took  out  a  patent  for  the  separation  of  the  coloring 
matter  of  blood,  and  also  for  drying  the  prepared  serous  matters.  He  recommends  the  blood 
(which  must  be  received  warm)  to  be  caught  in  shallow  vessels  containing  from  14  lbs.  to 
2i»  lbs.  of  blood,  to  stand  at  rest  from  two  to  six  hours  according  to  the  weather  and  the 
nature  of  the  blood  ;  then  the  clot  is  separated  by  a  strainer  from  the  serous  fluid,  and  by 
means  of  cutting-knives,  or  rollers,  the  clot  is  divided  into  small  pieces ;  a  considerable 
quantity  of  coloring  matter  flows  with  the  serum,  which  is  to  be  set  aside  to  deposit ;  the 
clot  is  placed  on  strainers  until  the  serum  has  all  dnuned  away.  By  these  operations  there 
are  obtained  readily  from  the  blood — 1st,  the  clot,  in  a  comparatively  dry  state,  comprising 
hematosine,  with  a  portion  of  serum  and  all  the  fibrine ;  2d,  a  portion  of  serum,  highly 
colored  with  hematosine  ;  3d,  the  clear  serum. 

The  blood,  in  small  fragments,  is  dried  on  wirework  or  trays,  at  a  less  temperature  than 
will  coagulate  the  hematosine,  so  that,  when  dry,  it  may  be  soluble  in  water ;    110"  to  115° 


BLOWPIPE. 


163 


6G 


is  the  temperature  recommended.     The  second  or  highly-colored  serum  can  be  dried  by 
itself  or  mixed  with  the  serum,  and  may  be  used  for  sugar  refining  and  in  dyeing. 

The  clear  serum  is  dried  and  ground  and  in  a  fit  state  to  be  used  as  albumen,  and  may 
be  employed  by  the  printers  of  textile  fabrics  for  fixing  ultramarine  blue  and  other  colors, 
or  as  a  substitute  for  egg  albumen,  both  in  printing  colors  and  in  refining  liquids. 

Instead  of  drying  at  once  the  clear  serum,  it  may  be  mixed  with  -^  per  cent,  of  oil  of 
turpentine.  Other  vegetable,  and,  particularly,  volatile  oils,  are  also  suitable,  preferring 
those  that  have  been  exposed  to  the  air ;  from  10  to  20  per  cent,  of  water,  ultramarine, 
suitable  colors,  or  thickening,  may  be  added,  taking  care  that  under  no  circumstance  is  it  to 
be  exposed  to  a  heat  high  enough  to  coagulate  it  while  in  the  drying-room. 

BLOODSTONE.  A  very  hard,  compact  variety  of  hwmatite  iron  ore,  which,  when 
reduced  to  a  suitable  form,  fixed  into  a  handle,  and  well  polished,  forms  the  best  descrip- 
tion of  burnisher  for  producing  a  high  lustre  on  gilt  coat-buttons.  The  gold  on  china  is 
burnished  by  the  same  means. — Knight. 

Bloodstone  is  a  name  also  applied  to  the  jaspery  variety  of  quartz  known  as  the  helio- 
trope, colored  deep-green,  with  interspersed  blood-red  spots  like  drops  of  blood — Dana. 

BLOWPIPE.  The  blowpipe  is  so  extremely  useful  to  the  manufacturer  and  to  the 
miner  that  an  exact  description  of  the  instrument  is  required. 

When  we  propel  a  flame  by  means  of  a  current  of  air  blown 
into  or  upon  it,  the  flame  thus  produced  may  be  divided  into  two 
parts',  as  possessing  different  properties — that  of  reducing  under 
one  condition  and  of  oxidizing  under  another. 

The  reducing  flame  is  produced  by  blowing  the  ordinary 
flame  of  a  lamp  or  candle  simply  aside  by  a  weak  current  of  air 
impinging  on  its  outer  surface  ;  it  is  therefore  unchanged  except 
in  its  direction.  Unconsumed  carbon,  at  a  white  heat,  giving  the 
yellow  color  to  the  flame,  coming  in  contact  with  the  substance, 
aids  in  its  reduction. 

The  oxidizing  flame  is  formed  by  pouring  a  strong  blast  of 
air  into  the  interior  of  the  flame  ;  combustion  is  thus  thoroughly 
established,  and  if  a  small  fragment  of  an  oxidizable  body  is  held 
just  beyond  the  point  of  the  flame,  it  becomes  intensely  heated, 
and,  being  exposed  freely  to  the  action  of  the  surrounding  air,  it 
is  rapidly  oxidized. 

The  best  form  of  blowpipe  is  the  annexed,  {flg.  66,)  which, 
with  the  description,  is  copied  from  Blandford's  excellent  transla- 
tion of  Dr.  Theodore  Scheerer's  "  Introduction  to  the  Use  of  the 
Mouth  Blowpipe." 

The  tube  and  nozzle  of  the  instrument  are  usually  made  of 
German  silver,  or  silver  with  a  platinum  point,  and  a  trumpet- 
shaped  mouth-piece  of  horn  or  ivory.  Many  blowpipes  have  no 
mouth-pieces  of  this  form,  but  are  simply  tipped  with  ivory,  or 
some  similar  material.  The  air-chamber  a  serves  in  some  degree 
to  regulate  the  blast  and  receives  the  stem,  b,  and  the  nozzle,  a, 
which  are  made  separately,  and  accurately  ground  into  it,  so  that 
they  may  be  put  together,  or  taken  apart  at  pleasure.  The  point 
6  is  best  made  of  platinum,  to  allow  of  its  being  readily  cleaned, 
and  is  of  the  form  shown  in  the  wood-cut.  When  the  in- 
strument is  used,  the  mouth-})iece  is  pressed  against  the  lips,  oi-, 
if  this  is  wanting,  the  end  of  the  stem  must  be  held  between  the 
lips  of  the  operator.  The  former  mode  is  far  less  wearying  than 
the  latter ;  and  whereas,  with  the  trumpet  mouth-piece,  it  is  easy 
to  maintain  a  continued  blast  for  five  or  ten  minutes,  without  it 
it  is  almost  impossible  to  sustain  an  imbroken  blast  of  more  than 
two  or  three  minutes'  duration.  While  blowing,  the  operator 
breathes  through  his  nostrils  only,  and,  using  the  epiglottis  as  a 
valve,  forces  the  air  through  the  blowpipe  by  means  of  the  check 
muscles. 

Some  years  since,  Mr.  John  Prideaux,  of  Plymouth,  printed  some  valuable  "  Sugges- 
tions" for  the  use  of  the  blowpipe  by  working  miners.  Sonic  portions  of  this  paper  appear 
so  useful,  especially  under  circumstances  which  may  preclude  the  use  of  superior  instru- 
ments, &c.,  that  it  is  thought  advisable  to  transfer  them  to  these  pages. 

For  ordinary  metalhirgic  assays,  the  common  blowpipe  does  very  well.  A  mere  taper- 
ing tube,  10  inches  long,  i  inch  (liameter  at  one  end,  and  the  ojiening  at  the  other  scarcely 
e(iual  to  admit  a  pin  of  the  smallest  kind,  the  smaller  end  curved  oft"  for  1  .J-  inch  to  a  right 
angle.  A  bulb  at  the  bend,  to  contain  the  vapor  condensed  from  the  breath,  is  u.seful  in  long 
operations,  but  may  generally  be  dispensed  with.      In  selecting  the  blowpipe,  the  small 


16i  BLOWPIPE. 

aperture  should  be  chosen  perfectly  round  and  smooth,  otherwise  it  will  not  command  a 
good  flame. 

A  common  candle,  such  as  the  miner  employs  under  ground,  answers  very  well  for  the 
flame. 

To  support  the  subject  of  assay,  or  "  the  assay,"  as  it  has  been  happily  denominated  by 
Mr.  Children,  two  different  materials  are  requisite,  according  as  we  wish  to  calcine  or  re- 
duce it.  For  the  latter  purpose,  nothing  is  so  good  as  charcoal ;  but  that  from  oak  is  less 
eligible,  both  from  its  inferior  combustibility  and  from  its  containing  iron,  than  that  from 
alder,  willow,  or  other  light  woods. 

For  calcination,  a  very  convenient  support,  where  platinum  wire  is  difficult  to  procure, 
is  white-baked  pii)e-clay  or  china  clay,  selecting  such  as  will  not  fuse  nor  become  colored  by 
roasting  with  borax. 

These  supports  are  conveniently  formed  by  a  process  of  Mr.  Tennant.  The  clay  is  to  be 
beaten  to  a  smooth  stiff  body  ;  then  a  thin  cake  of  it,  being  placed  between  a  fold  of  writing 
paper,  it  is  to  be  beaten  out  with  a  mallet  to  the  thickness  of  a  wafer,  and  cut,  paper  and 
all,  into  squares  of  f  inch  diameter,  or  triangles  about  the  same  size.  These  are  to  be  put 
in  the  bowl  of  a  tobacco-pipe,  and  heated  gently  till  dry,  then  baked  till  the  paper  is  burnt 
away,  and  the  clay  left  perfectly  white.  They  should  be  baked  in  a  clear  fire,  to  keep  out 
coal-dust  and  smoke  as  much  as  possible,  as  either  of  these  adhering  to  the  clay  plates 
would  color  the  borax  in  roasting.  A  small  fragment  of  the  bowl  of  a  new  tobacco-pipe 
will  serve  instead  in  the  absence  of  a  more  convenient  material, 

A  simple  pair  of  forceps,  (Jig.  67),  to  move  and  to  take  up  the  hot  assay,  may  be  made 
of  a  slip  of  stiff  tin  plate,  8  inches  long,  ^  inch  wide  in  the  middle,  and  Vio  inch  at  the 

ends.  The  tin  being  rubbed  off"  the  points  on  a  rough 
67  whetstone,  the  slip  is  to  be  bent  until  they  approach  each 

fi                                    ~       -^   other  within  ^  an  inch,  and  the  two  sides  are  parallel ; 
^^ thus  there  will  be  spring  enough  in  the  forceps  to  open 
~_^    and  let  go  the  assay  when  not  compressed  upon  it  by  the 
finger  and  thumb. 
A  magnetic  needle,  very  desirable  to  ascertain  the  presence  of  iron,  is  easily  made  of 
the  requisite  delicacy  where  a  magnet  is  accessible.     A  bit  of  thin  steel  wire,  or  a  long  fine 
stocking-needle,  having  \  inch  cut  off"  at  the  point,  is  to  be  heated  in  the  middle  that  it 
may  be  slightly  bent  there,  {Jig.  68.)     While  hot,  a  bit  of  sealing-wax  is  to  be  attached  to 
the  centre,  and  the  point  which  had  been  cut  off,  being  heated 
68                         at  the  thick  end,  is  to  be  fixed  in  the  sealing-wax,  so  that  the 
l__^                      sharp  end  may  serve  as  a  pivot,  descending  about  ^  inch  below 
^ — -— -.____^    the  centre,  taking  care  that  the  ends  of  the  needle  fall  enough 
' —            [!ivi-^\                     below  the  pivot,  to  prevent  it  overturning.     It  must  be  mag- 
'v:;;'!                     netized,  by  sliding  one  end  of  a  magnet  half  a  dozen  or  more 
>■■'"  J                     times  from  the  centre  to  one  end  of  the  needle,  and  the  other 
end  a  similar  number  of  times  from  the  centre  of  the  needle  to 
its  other  end.     A  small  brass  thimble  (not  capped  with  iron)  will  do  for  the  support,  the 
point  of  the  pivot  being  placed  in  one  of  the  indentations  near  the  centre  of  the  tap,  when, 
if  well  balanced,  it  will  turn  until  it  settles  north  and  south.     If  one  side  preponderate, 
it  must  be  nipped  until  the  balance  be  restored. 

A  black  gun-flint  is  also  occasionally  used  to  rub  the  metallic  globules,  (first  attached, 
whilst  warm,  to  a  bit  of  sealing-wax,)  and  ascertain  the  color  of  the  streak  which  they  give. 
Thus  minute  particles  of  gold,  copper,  silver,  &c.,  are  readily  discriminated.  A  little  refined 
borax  and  carbonate  of  soda,  both  in  powder,  will  complete  the  requisites. 

Having  collected  these  materials,  the  next  object  for  the  operator  is  to  acquire  the 
faculty  of  keeping  up  an  unintermitted  blast  through  the  pipe  whilst  breathing  freely 
through  the  nose. 

A  very  sensitive,  and,  for  most  purposes,  sufficiently  delicate  balance,  {Jig.  69,)  was 
also  devised  by  Mr.  Prideaux,  of  which  the  following  is  a  description  : — 

69 


The  common  marsh  reed,  growing  generally  in  damp  places  throughout  the  kingdom, 
will  yield  straight  joints,  from  8  to  12,  or  more,  inches  long ;  an  8-inch  joint  will  serve,  but 
the  longer  the  better.     This  joint  is  to  be  split  down  its  whole  length,  so  as  to  form  a 


BLUE  COPPERAS,  oe  BLUE  STOKE.  165 

trough,  say  ^  inch  wide  in  the  middle,  narrowed  away  to  ^  inch  at  the  ends.  A  narrow 
slip  of  writing  paper,  the  thinner  the  better,  (bank  post  is  very  convenient  for  the  purpose,) 
and  as  long  as  the  reed  trough,  is  to  be  stuck  with  common  paste  on  the  face  of  a  carpen- 
ter's rule,  or,  in  preference,  that  of  an  exciseman, — as  the  inches  are  divided  into  tenths 
instead  of  eighths  ; — in  either  case  observing  that  the  divisions  of  the  inch  on  the  rule  be 
left  uncovered  by  the  paper.  When  it  is  dry,  lines  must  be  drawn  the  whole  length  of  it, 
g  inch  apart,  to  mark  out  a  stripe  ^  inch  wide.  Upon  this  stripe  the  divisions  of  the  inch 
are  to  be  ruled  off  by  means  of  a  small  square. 

The  centre  division  being  marked  0,  it  is  to  be  numbered  at  every  fourth  line  to  the 
ends.  Thus  the  fourth  from  the  centre  on  each  side  will  be  10 ;  the  eighth,  20 ;  the 
twelfth,  30  ;  the  sixteenth,  40,  &c.  ;  and  a  slip  of  10  inches  long,  graduated  into  tenths  of 
an  inch,  will  have  on  each  arm  50  lines,  or  125  degrees,  divided  by  these  lines  into  quar- 
ters. While  the  lines  and  numbers  are  drying,  the  exact  centre  of  the  reed-trough  may  be 
ascertained,  and  marked  right  across,  by  spots  on  the  two  edges.  A  line  of  gum  water, 
full  ^  inch  wide,  is  then  laid  with  a  camel-hair  pencil  along  the  hollow,  and  the  paper 
being  stripped  from  the  rule,  (which  it  leaves  easily,)  the  graduated  stripe  is  cut  out  with 
scissors,  and  iaid  in  the  trough,  with  the  line  0  exactly  in  the  centre.  Being  pressed  to  the 
gummed  reed,  by  passing  the  round  end  of  a  quill  along  it,  it  graduates  the  trough  from  the 
centre  to  each  end.  This  graduation  is  very  true,  if  well  managed,  as  the  paper  does  not 
stretch  with  the  gum  water  after  being  laid  on  the  rule  with  the  paste. 

A  very  fine  needle  is  next  to  be  procured,  (those  called  6erto?-needles  are  the  finest,)  and 
passed  through  a  slip  of  cork  the  width  of  the  centre  of  the  trough,  about  \  inch  square, 
•J-  thick.  It  should  be  passed  through  with  care,  so  as  to  be  quite  straight.  The  cork 
should  then  be  cut  until  one  end  of  it  fits  into  the  trough,  so  that  the  needle  shall  bear  on 
the  edges  exactly  in  the  spots  that  mark  the  centre,  as  it  is  of  importance  that  the  needle 
and  the  trough  be  exactly  at  right  angles  with  each  other.  The  cork  is  now  to  be  fixed  in 
its  place  with  gum  water,  and,  when  fast  dry,  to  be  soldered  down  on  each  side  with  a  small 
portion  of  any  soft  resinous  cement,  on  the  point  of  a  wire  or  knitting-needle ;  a  little 
cement  being  also  applied  in  the  same  manner  to  the  edges  of  the  cork  where  the  needle 
goes  through,  to  give  it  firmness,  the  beam  is  finished.  It  may  be  balanced  by  paring  the 
edges  on  the  heaviest  side :  but  accurate  adjustment  is  needless,  as  it  is  subject  to  vary  with 
the  dampness  or  the  dryness  of  the  air. 

The  support  on  which  it  plays  is  a  bit  of  tin  plate,  (or,  in  preference,  brass  plate,)  If 
inch  long,  and  1  inch  wide.  The  two  ends  are  turned  up  square  ^  of  an  inch,  giving  a  base 
of  f  of  an  inch  wide,  and  two  upright  sides  f  high.  The  upper  edges  are  then  rubbed 
down  smooth  and  scjuare  upon  a  Turkey  stone,  letting  both  edges  bear  on  the  stone  to- 
gether, that  they  may  exactly  correspond.  For  use,  the  beam  is  placed  evenly  in  the  sup- 
port, with  the  needle  resting  across  the  edges.  Being  brought  to  an  exact  balance  by  a  bit 
of  writing  paper,  or  any  other  substance,  placed  on  the  lighter  side,  and  moved  toward  the 
end  until  the  equilibrium  is  produced,  it  will  turn  with  extreme  delicacy,  a  bit  of  horsehair, 
\  inch  long,  being  sufficient  to  bring  it  down  freely. 

It  must  not  be  supposed  that  any  such  instrument  as  this  is  recommended  as  in  any  way 
substituting  the  beautiful  balances  which  are  constructed  Tor  the  chemist,  and  others  requir- 
ing to  weigh  with  great  accuracy.  The  object  is  merely  to  show  the  miner  a  method  by 
which  he  may  construct  for  himself  a  balance  which  shall  be  sufficiently  accurate  for  such 
blowpipe  investigations  as  it  may  be  important  for  him  to  learn  to  perform  for  himself.  If 
the  suggestions  of  the  chemist  who  devised  the  above  balance  had  been  carried  out,  much 
valuable  mineral  matter  which  has  been  lost  might  have  been  turned  to  profitable  account. 

The  blowpipe  is  largely  used  in  manufactures,  as  in  soldering,  in  hardening  and  temper- 
ing small  tools,  in  glass-blowing,  and  in  enamelling.  In  many  cases  the  blowpipes  are  used 
in  the  mouth,  but  frequently  they  are  supplied  with  air  from  a  bellows  moved  by  the  foot, 
by  vessels  in  which  air  is  condensed,  or  by  means  of  pneumatic  apparatus. 

Many  blowpipes  have  been  invented  for  the  employment  of  oxygen  and  hydrogen,  by 
the  combustion  of  which  the  most  intense  heat  which  we  can  produce  is  obtained.  Pro- 
fessor Hare,  of  Philadelphia,  was  the  first  to  employ  this  kind  of  blowpipe,  when  he  was 
speedily  followed  by  Clark,  Gurney,  Leeson,  and  others.  The  blowpipe,  fed  with  hydro- 
gen, is  employed  in  many  soldering  processes  with  much  advantage. 

The  general  form  of  the  "  workshop  blowpipe  "  is  that  of  a  tube  open  at  one  end,  and 
supported  on  trunnions  in  a  wooden  pedestal,  so  that  it  may  he  pointed  vertically,  horizon- 
tally, or  at  any  angle  as  desired.  Common  street  gas  is  supplied  through  one  hollow  trun- 
nion, and  it  escapes  through  an  annular  opening,  while  common  air  is  admitted  through  tlic 
other  trunnion,  which  is  also  hollow,  and  is  discharged  in  the  centre  of  the  hydrogen  through 
a  central  conical  tube ;  the  magnitude  and  intensity  of  the  fiame  being  determined  by  the 
relative  quantities  of  gas  and  air,  and  by  the  greater  or  less  protrusion  of  the  inner  cone,  by 
which  the  annular  space  for  the  hydrogen  is  contracted  in  any  required  degree. — Holtz- 
apffcl. 

'  BLUE  COPPERAS,  or  BLUE  STONE.      The  commercial  or  common  names  of  the 
sulphate  of  copper.     See  Copper. 


166  BLUE  YITEIOL. 

BLUE  VITRIOL.  Sulphate  of  copper.  When  found  in  nature,  it  13  due  entirely  to 
the  decomposition  of  the  sulphides  of  copper,  especially  of  the  yellow  copper  pyrites,  which 
are  Uable  to  this  change  when  placed  under  the  influence  of  moist  air,  or  of  water  contain- 
ing air. 

BOGHEAD  COAL,  and  other  JBrown  Cannel  Coals.  The  brown  cannels  are  chiefly 
confined  to  Scotland,  and  have  been  wrought,  with  the  exception  of  the  celebrated  Bog- 
head, for  the  last  thirty  years.  They  arc  found  at  Boghead,  near  Bathgate ;  Eocksoles, 
near  Airdrie  ;  Pirnie,  or  Methill ;  Capeldrea,  Kirkness,  and  Wemyss,  in  Fife.  The  first- 
named  coal,  about  which  there  has  been  so  much  dispute  as  to  its  nature,  has  only  been  in 
the  market  eight  years.  It  is  considered  the  most  valuable  coal  hitherto  discovered  for  gas 
and  oil-making  purposes ;  but,  strange  to  say,  the  middle  portion  of  the  Pirnie,  or  Met- 
hill seam,  which  has  been  unnoticed  for  thirty  years,  is  nearly  as  valuable  for  both  pur- 
poses. 

Boghead.  Amorphous ;  fracture  subconchoidal,  compact,  containing  impressions  of 
the  stems  of  Sicjillaria,  and  its  roots,  (Stipnarias,)  with  rootlets  traversing  the  mass. 
Color,  clove  brown,  streak  yellow,  without  lustre  ;  a  non-electric  ;  takes  fire  easily,  splits,  but 
does  not  fuse,  and  burns  with  an  empyreumatic  odor,  giving  out  much  smoke,  and  leaving 
a  considerable  amount  of  white  ash.     H.  25.     Specific  gravity,  1"200. 

According  to  Dr.  Stenhouse,  F.  R.  S.,  its  composition  is: — 

Carbon 65-72 

Hydrogen 9-03 

Nitrogen 0'72 

Oxvgen-        -- 4-78 

Ash 19-75 


100-00 
Dr.  Stenhouse's  analysis  of  the  ash  of  Boghead  coal,  from  three  analyses,  was  as  fol- 
lows : — 

Silica 58-31 

Alumina  .-..-...-..     33-65 

Sesquioxide  of  iron --       7-00 

Potash 0-84 

Soda 0-41 

Lime  and  sulphuric  acid traces. 

Dr.  Andrew  Fyfc,  F.  R.  S.  E.,  on  analysis,  found  that  the  coal  yielded,  from  a  picked 
specimen,  70  per  cent,  of  volatile  matter,  and  3n  per  cent,  of  coke  and  ash.  From  a  ton 
he  obtained  14-880  cubic  feet  of  gas,  the  illuminating  power  of  which  was  determined  Ijy 
the  use  of  the  Bunsen  photometer,  the  gas  being  consumed  by  argands  burning  from  2A  to 
Si  feet  per  hour,  according  to  circumstances.  The  candle  referred  to  was  a  spermaceti 
candle,  burning  140  grains  per  hour.  . 


Cubic  Feet  of 

Gas  per  Ton  of 

Coal. 

Q^«„;fi»            Condensation 
Specific              ^     Chlorine 
Gravity.            in  100  Parts. 

Durability  1  foot 
burns. 

Illuminating 
Power  1  foot  ^ 
Light  of  Candles. 

Pounds  of  Coke 

per  Ton  of 

Coal. 

14-880 

•802 

27 

Min.     Sec 
88      25 

^7-72 

760 

The  Pirnie  or  Methill  brown  cannel,  on  analysis,  gives  the  following  results : — 

Specific  gravity        ........  1-126 

Gas  per  ton     - 13,500  feet. 

Illuminating  power 28  candles. 

Coke  and  ash 36  per  cent. 

Hydro-carbons  condensed  by  bromine       .         -         -         .  20       " 

Sulphuretted  hydrogen i" 

Carbonic  acid 4f     " 

Carbonic  oxide 7f" 

Volatile  matter  in  coal 65       " 

Specific  gravity  of  gas -700       " 

The  Boghead  coal  occurs  in  the  higher  part  of  the  Scotch  coal  field ;  in  about  the  posi- 
tion of  the  "  slaty  band  "  of  ironstone,  its  range  is  not  more  than  3  or  4  miles  in  the  lands 
of  Torbanc,  Inchcrnss,  Boghead,  Capper's,  and  Bathvale,  near  Bathgate,  in  the  county  of 
Linlithgow.  In  thickness  it  varies  from  1  to  30  inches,  and  at  the  present  consumption,  say 
from  80,000  to  10i»,000  tons  per  annum,  it  cannot  last  many  years. 


BOG  IKON  ORE. 


167 


The  following  section  of  a  pit  at  Torbane  shows  that  the  cannel  occurs  in  ordinary  coal 
measures,  and  under  circumstances  common  to  beds  of  coal : — 

Ft.       In. 

Boghead  house  coal --2         7 

Arenaceous  shale 6         0 

Slaty  sandstone 07 

Shale  and  ironstone,  containing  remains  of  plants  and  shells        -     0       10 

Cement  stone  (impure  ironstone) 0         4 

Boghead  cannel  19 

Fire  clay,  full  of  Stigmarice         -------05 

Coal  (common) 06 

Black  shale 0         Of 

Coal 0         1 

Shale -        -        -     0        Of 

Coal 0         0^ 

Fire  clay 0         H 

Hard  shale 03 

Thin  laminae  of  coal  and  shale     -• 0         3^ 

Common  coal        ...--.--.-0         6 
Fire  clay 0         0 

One  of  the  chief  characters  of  this  cannel  is  its  indestructibility  under  atmospheric 
agencies  ;  for  whether  it  is  taken  from  the  mine  at  a  depth  of  fifty  fathoms,  or  at  the  out- 
crop, its  gas  and  oil-yielding  properties  ai'e  the  same.  Even  a  piece  of  the  mineral  taken 
out  of  the  drift  deposits,  where  it  had  most  probably  lain  for  thousands  of  years,  appears 
to  be  just  the  same  in  quality  as  if  it  had  been  but  lately  raised  from  the  mine. 

In  the  earth  the  seam  lies  parallel  to  its  roof  and  floor,  like  other  beds  of  coal ;  and  it  is 
traversed  by  the  usual  vertical  joints,  dividing  it  into  the  irregular  cubes  which  so  generally 
characterize  beds  of  cannel.  The  roof  lying  above  the  cement  stone  contains  remains  of 
Ca'amites ;  and  the  ironstone  nodules,  fossil  shells  of  the  genus  Vnio.  The  floor  of  the 
mine  contains  Stiginarke ;  and  the  coal  itself  affords  more  upright  stems  of  Siyillarice,  and 
its  roots  {StigmaricB)  and  their  radicles,  running  through  the  seam  to  a  considerable  dis- 
tance, than  the  majority  of  coals  show.  In  these  respects  it  entirely  resembles  the  Pirnie 
or  Methill  seam.  Most  cannels  afford  remains  of  fish ;  but  in  Boghead  no  traces  of  these 
fossils  have  yet  been  met  with,  although  they  have  been  diligently  sought  after. 

The  roots  in  the  floors,  and  the  upright  stems  of  trees  in  the  seam  itself,  appear  to  show 
that  the  vegetable  matter  now  forming  the  coal  grew  on  the  spot  where  it  is  found.  If  the 
mangroves  and  other  aquatic  plants,  at  the  present  day  found  growing  in  the  black  vegetable 
mud  of  the  marine  swamps  of  Brass  town,  on  the  west  coast  of  Africa,  were  quietly  sub- 
merged and  covered  up  with  clay  and  silt,  we  should  have  a  good  illustration  of  the  forma- 
tion of  a  bed  of  carbonaceous  matter  showing  no  structure,  mingled  with  stems  and  roots 
of  trees  showing  structure,  which  is  the  case  of  Boghead  coal,  the  structure  being  only  de- 
tected in  those  parts  showing  evidence  of  stems  and  roots,  and  not  in  the  matrix  in  which 
those  fossils  are  contained. 

The  chemical  changes  by  which  vegetable  matter  has  been  converted  into  Boghead  can- 
nel will  not  be  here  dwelt  on ;  but  the  chief  peculiarity  about  the  seam  is  its  close  and 
compact  roof,  composed  of  cement  stone  and  shale.  This  is  perfectly  water  and  air-tight, 
so  much  so  that,  although  the  mine  is  troubled  with  a  great  quantity  of  water,  it  all  comes 
through  the  floor,  and  not  the  roof.  This  tight  covering  of  the  coal  has  doubtless  exercised 
considerable  influence  on  the  decomposing  vegetable  matter  after  the  latter  had  been  sub- 
merged. It  is  worthy  of  remark,  that,  above  the  Pirnie  or  Methill  seam, — the  coal  nearest 
approaching  Boghead, — a  similar  bed  of  impure  ironstone  occurs. 

Away  from  whin  dykes  which  traverse  the  coal  field,  there  are  no  appearances  of  the 
action  of  an  elevated  temperature,  either  upon  the  coal  or  its  adjoining  strata,  to  give  any 
sanction  to  the  hypothesis  that  the  cannel  has  resulted  from  the  partial  decomposition  of  a 
substratum  of  coal  by  the  heat  of  underlying  trap,  the  volatile  matters  having  been  retained 
in  what  has  probably  been  a  bed  of  shale.  First,  it  must  be  understood  that  Boghead  can- 
nel, even  when  treated  with  boiling  naphtha,  affords  scarcely  a  trace  of  bitumen ;  and, 
secondly,  when  the  seam  of  coal  is  examined  in  the  neighborhood  of  a  whin  dyke,  where 
heat  has  evidently  acted  on  it,  it  is  found  nothing  like  cannel,  but  as  a  soft  sticky  substance, 
of  a  brown  color,  resembling  burnt  Indian-rubber.  Besides  these  facts,  the  seams  of  coal 
and  their  accompanying  strata,  both  above  and  below  the  cannel,  show  no  signs  of  the  ac- 
tion of  heat,  but,  on  the  contrary,  exhibit  every  appearance  of  having  been  deposited  in  the 
usual  way,  and  of  remaining  without  undergoing  any  particular  alteration. — E.  W.  B. 

BOGHEAD  NAPHTHA,  {syu.  Bathgate  naphtha,)  naphtha  from  the  Boghead  coal.  See 
Naphth.vJ  Booiiead. 

BOG  IRON  ORE  is  an  example  of  the  recent  formation  of  an  ore  of  iron,  arising  from 
the  decomposition  of  rocks,  containing  iron,  by  the  action  of  water  charged  with  carbonic 


168  BOILER. 

acid.  The  production  of  this  ore  of  iron  in  the  present  epoch,  explains  to  us  many  of  the 
conditions  under  which  some  of  the  more  ancient  beds  of  iron  ore  have  been  produced. 

Bo"  iron  ore  is  common  in  the  peat  bogs  of  Ireland  and  other  places. 

The  iron  manufactured  from  bog  iron  ore  is  what  is  called  "  cold  short,"  from  the  pres- 
ence of  phosphorus ;  it  cannot,  therefore,  be  employed  in  the  manufacture  of  wire,  or  of 
sheet  iron  ;  but,  from  the  fluidity  of  the  metal,  it  is  valuable  for  casting. 

It  varies  much  in  composition,  some  specimens  giving  20  and  others  70  per  cent,  of  the 
peroxide  of  iron.  Protoxide  of  iron  and  oxide  of  manganese  are  often  present ;  and  as 
much  as  10  per  cent,  of  phosphorus  and  organic  matter  have  been  detected.     See  Ii;on. 

BOILER.     See  Boilers,  vol.  i. 

BOLE.  A  kind  of  clay,  often  highly  colored  by  iron.  It  usually  consists  of  silica,  alu- 
mina, iron,  lime,  and  magnesia.  It  is  not  a  well-defined  mineral,  and,  consequently,  many 
substances  are  described  by  mineralogists  as  bole. 

Armenian  bole  is  of  a  bright  red  color.  This  is  frequently  employed  as  a  dentifrice, 
and  in  some  cases  it  is  administered  medicinally. 

Bole  of  Bloia  is  yellow,  contains  carbonate  of  lime,  and  effervesces  with  acids. 

Bo/iemiau  bole  is  a  yellowish  red. 

French  bole  is  of  a  pale  red,  with  frequent  streaks  of  yellow. 

Lemnian  bole  and  Siliscan  bole  are,  in  most  respects,  similar  to  the  above-named  va- 
rieties. 

The  following  analysis  are  by  C.  Van  Haucr: — 

Capo  di  Bove — Silica,  45-64;  alumina,  29-33;  peroxide  of  iron,  8-88;  lime,  0*60; 
magnesia,  a  trace ;  water,  14-27  =  98-72. 

New  Holland — Silica,  38-22;  alumina,  31-00;  peroxide  of  iron,  11-00;  lime,  a  trace; 
magnesia,  a  trace  ;  water,  18-81  =  99-03. 

BOLOGNIAN  STONE.  A  sulphate  of  barytes,  found  in  roundish  masses,  which  phos- 
phoresces when,  after  calcination,  it  is  exposed  to  the  solar  rays. 

BOMBAZINE.  A  worsted  stuff  mixed  with  silk  ;  it  is  a  twilled  fabric,  of  which  the  warp 
is  silk  and  the  weft  worsted. 

BOMBYX  MORI.  The  moth  to  which  the  silkworm  turns.  This  species  was  originally 
brought  from  China.  In  this  country  the  eggs  of  this  moth  are  hatched  early  in  May.  The 
caterpillar  (silkworm)  is  at  first  of  a  dark  color  ;  but  gradually,  as  with  all  other  caterpillars, 
it  becomes  lighter  colored.  This  worm  is  about  eight  weeks  in  arriving  at  maturity,  during 
which  time  it  frequently  changes  its  color.  When  full  grown,  the  silkworm  commences 
spinning  its  web  in  some  convenient  place.  The  silkworm  continues  drawing  its  thread 
from  various  points,  and  attaching  it  to  others ;  it  follows,  therefore,  that,  after  a  time,  the 
body  becomes,  in  a  great  measure,  enclosed  in  the  thread.  The  work  is  then  continued 
from  one  thread  to  another,  the  silkworm  moving  its  head  and  spinning  in  a  zigzag  way, 
bending  the  fore  part  of  the  body  back  to  spin  in  all  directions  within  reach,  and  shifting 
the  body  only  to  cover  with  silk  the  part  which  was  beneath  it.  As  the  silkworm  spins  its 
web  by  thus  bending  the  fore  part  of  the  body  back,  and  moves  the  hinder  part  of  the  body 
in  such  a  way  only  as  to  enable  it  to  reach  the  farther  back  with  the  fore  part,  it  follows 
that  it  encloses  itself  in  a  cocoon  much  shorter  than  its  own  body  ;  for  soon  after  the  begin- 
ning, the  whole  is  continued  with  the  body  in  a  bent  position.  During  the  time  of  spinning 
the  cocoon,  the  silkworm  decreases  in  length  very  considerably ;  and  after  it  is  completed 
it  is  not  half  its  original  length  ;  at  this  time  it  becomes  quite  torpid,  soon  changes  its  skin, 
and  appears  in  the  form  of  a  chrysalis.  The  time  required  to  complete  the  cocoon  is  five 
days.  In  the  chrysalis  state  the  animal  remains  from  a  fortnight  to  three  weeks ;  it  then 
bursts  its  case,  and  comes  forth  in  the  imago  state,  the  moth  having  previously  dissolved  a 
portion  of  the  cocoon  by  means  of  a  fluid  which  it  ejects. — Penny  Mar/azine. 

BON-BONS.  Comfits  and  other  sweetmeats  of  various  descriptions  pass  under  this  name. 
A  large  quantity  is  regularly  imported  from  France  into  this  country,  and,  from  its  usually 
superior  quality,  it  is  much  in  request.  The  manufacture  of  sweetmeats,  confectionary,  &c., 
docs  not  enter  so  far  into  the  plan  of  this  work  as  to  warrant  our  giving  any  special  detail 
of  the  various  processes  employed. 

Liqueur  Bon-bons  are  made  in  the  following  manner : — A  syrup  evaporated  to  the  proper 
'  consistence  is  made,  and  some  alcoholic  liqueur  is  added  to  it.  Plaster  of  Paris  models  of 
the  required  form  are  made  ;  and  these  are  employed,  several  being  fastened  to  a  rod,  for 
the  purpose  of  making  moulds  in  powdered  starch,  filling  shallow  trays.  The  syrup  is  then, 
by  means  of  a  funnel,  poured  into  these  moulds,  and  there  being  a  powerful  repulsion  be- 
tween the  starch  and  the  alcoholic  syrup,  the  upper  portion  of  the  fluid  assumes  a  spherical 
form  ;  then  some  starch  is  sifted  over  the  surface,  and  the  mould  is  placed  in  a  warm  closet. 
Crystallization  commences  on  the  outside  of  the  bon-l)on,  forming  a  crust  inclosing  the 
syrup,  which  constantly  gives  up  sugar  to  the  crystallizing  crust  until  it  becomes  sufilciently 
firm  to  admit  of  being  removed.  A  man  and  two  boys  will  make  three  hundredweights  of 
bon-bons  in  a  day. 


BONES.  169 

Crystallized  Bon-bons  are  prepared  by  putting  them  with  a  strong  syrup  contained  in 
shallow  dishes,  placed  on  shelves  in  the  drying  chamber,  pieces  of  linen  being  stretched 
over  the  surface,  to  prevent  the  formation  of  a  crust  upon  the  surface  of  the  fluid.  In  two 
or  three  days  the  bon-bons  are  covered  with  crystals  of  sugar ;  the  syrup  is  then  drained 
off,  and  the  comfits  dried. 

Fainted  Bon-bons. — Bon-bons  are  painted  by  being  first  covered  with  a  layer  of  glazing ; 
they  are  then  painted  in  body  colors,  mixed  with  mucilage  and  sugar. 

The  French  have  some  excellent  regulations,  carried  out  uuder  the  "  Prefet  de  Police," 
as  to  the  colors  which  may  be  employed  in  confectionary.  These  are  to  the  following 
efi'ect  :— 

"  Considering  that  the  coloring  matter  given  to  sweets,  bon-bons,  liqueurs,  lozenges, 
&c.,  is  generally  imparted  by  mineral  substances  of  a  poisonous  nature,  which  imprudence 
has  been  the  cause  of  serious  accidents ;  and,  that  the  same  character  of  accidents  have 
been  produced  by  chewing  or  sucking  the  wrapping  paper  of  such  sweets,  it  being  glazed 
and  colored  with  substances  which  are  poisonous ;  it  is  expressly  forbidden  to  make  use  of 
any  mineral  substance  for  coloring  liqueurs,  bon-bons,  sugar-plums,  lozenges,  or  any  kind  of 
sweetmeats  or  pastry.  No  other  coloring  matter  than  such  as  is  of  a  vegetable  character 
shall  be  employed  for  such  a  purpose.  It  is  forbidden  to  wrap  sweetmeats  in  paper  glazed 
or  colored  with  mineral  substances.  It  is  ordered  that  all  confectioners,  grocers,  dealers  in 
liqueurs,  bon-bons,  sweetmeats,  lozenges,  &c.,  shall  have  their  name,  address,  and  trade 
printed  upon  the  paper  in  which  the  above  articles  shall  be  enclosed.  All  manufacturers  and 
dealers  are  personally  responsible  for  the  accidents  which  shall  be  traced  to  the  liqueurs, 
bon-bons,  and  other  sweetmeats  manufactured  or  sold  by  them." 

If  similar  provisions  were  in  force  in  this  country,  it  would  prevent  the  use,  to  an  alarm- 
ing extent,  in  our  cheap  confectionary,  of  such  poisonous  substances  as 
Arsenite  of  copper,  Sulphide  of  arsenic, 

Acetate  of  copper.  Oxide  of  lead, 

Chromate  of  lead.  Sulphide  of  mercury,  &c. 

The  coloring  matters  allowed  to  be  used  in  France  are  indigo,  Prussian  blue,  saffron, 
Turkey  yellow,  quercitron,  cochineal,  Brazil  wood,  madder,  &c. 

BONES.  Heintz  found  that  the  fixed  bases  in  the  bones  were  sufficient  to  saturate 
completely  the  acids  contained  in  them,  so  that  the  phosphate  of  lime,  as  well  as  the  phos- 
phate of  magnesia,  which  the  bones  contain,  is  composed,  according  to  the  formula  3R0,  P0^ 
Bone  phosphate  of  lime  was  considered  by  Berzelius  to  be  8Ca0,  3P0'.  True  bony  struc- 
ture is  perfectly  free  from  chlorides,  from  sulphates,  and  from  iron,  these  salts  being  only 
found  when  the  liquid  pervading  the  bones  has  not  been  completely  removed.  The  bones 
in  youth  contain  less  earthy  constituents  than  those  of  adults ;  and,  in  advanced  age,  the 
proportion  of  mineral  matters  increases.  Von  Biria  found  more  bone  earth  in  the  bones  of 
birds  than  in  those  of  mammals ;  he  found  also  the  ratio  of  the  carbonate  of  lime  to  the 
phosphate  to  be  generally  greater.  In  the  bones  of  amphibia^  he  found  less  inorganic  mat- 
ter than  in  those  of  mammals  and  birds ;  and,  in  the  bones  of  fishes,  the  earthy  matters 
vary  from  21  to  57  per  cent.  The  scales  of  fishes  have  a  composition  somewhat  similar  to 
that  of  bone,  but  they  contain  phosphate  of  lime  in  small  quantity  only. 

In  certain  diseases,  (the  craniotabes  in  children,)  the  earthy  salts  fall  in  the  spongy  por- 
tion of  the  bone  as  low  as  28-16  per  cent,  of  the  dry  bone  ;  and  in  several  cases  the  propor- 
tion of  earthy  matter  was  found  by  SchlossberTcr  as  low  as  50  per  cent.  At  the  age  of  21 
years,  the  weight  of  the  skeleton  is  to  that  of  the  whole  body  in  the  ratio  of  10-5  :  100  in 
man,  and  in  that  of  8-5  :  100  in  woman,  the  weight  of  the  body  being  about  125  or  130  lbs. 

The  quantity  of  organic  matter  in  fossil  bones  varies  very  considerably  :  in  some  cases 
it  is  found  in  as  large  a  quantity  as  in  fresh  bones,  while  in  others  it  is  altogether  wanting. 
Carbonate  of  lime  generally  occurs  in  far  larger  quantity  in  fossil  than  in  recent  bone's, 
which  may  arise  from  infiltration  of  that  salt  from  without,  or  from  a  decomposition  of  a 
portion  of  the  phosphate  of  lime  by  carbonic  acid  or  carbonates.  Magnesia  often  occurs  in 
larger  quantities  in  the  fossil  remains  of  vertebrated  animals  than  in  the  fresh  bones  of  the 
present  animal  world.  Liebig  found  in  the  cranial  bones  excavated  at  Pompeii  a  larger 
proportion  of  fluoride  of  calcium  than  in  recent  bones ;  while,  on  the  other  hand,  Girar- 
din  and  Preisser  found  that  this  salt  had  greatly  diminished  in  bones  which  had  lain  long  in 
the  earth,  and,  in  some  cases,  had  even  wholly  disappeared. 

The  gelatinous  tissue  of  bones  was  found  by  Von  Biria  to  consist  of 

Ox  bones.  Fossil  bones. 

Carbon         ....     5o-4()i  ....  50-130 

Hydrogen    -        -        -        -      7-111  -        -        -        -  7-073 

Nitrogen      ....     18-154  ....  18-449 

Oxygen        ....     24119  ....  24-348 
Sulphur        ....       0-216 
This  is  the  same  composition  as  that  of  the  gelatinous  tissues. 


170 


BONES. 


In  the  arts,  bones  are  employed  by  turners,  cutlers,  manufacturers  of  animal  charcoal, 
and,  when  calcined,  by  assayers,  for  making  cupels.  In  agriculture,  they  are  employed  as 
a  manure.  Laid  on  in  the  form  of  dust,  at  the  rate  of  30  to  35  cwts.  per  acre,  they  have 
been  known  to  increase  the  value  of  old  pastures  from  10s.  or  15s.  to  30s.  or  40s.  per  acre  ; 
and  after  the  lapse  of  20  years,  though  sensibly  becoming  less  valuable,  land  has  remained 
still  worth  two  or  three  times  the  rent  it  paid  before  the  bones  were  laid  on.  In  the  large 
dyeing  establishments  in  Manchester,  the  bones  are  boiled  in  open  pans  for  24  hours,  the 
flxt  skinmied  oft'  and  sold  to  the  candle  makers,  and  the  size  afterwards  boiled  down  in  an- 
other vessel  till  it  is  of  sufficient  strength  for  stiffening  tlie  thick  goods  for  which  it  is  in- 
tended. The  size  liquor,  when  exhausted  or  no  longer  of  sufficient  strength,  is  applied  with 
much  benefit  as  a  manure  to  the  adjacent  pasture  and  artificial  grass  lands,  and  the  ex- 
hausted bones  are  readily  bought  up  by  the  Lancashire  and  Cheshire  farmers.  When  burned 
bones  are  digested  in  sulphuric  acid  diluted  with  twice  its  weight  of  water,  a  mixture  of 
gypsum  and  acid  phosphate  of  lime  is  obtained,  which,  when  largely  diluted  with  water, 
forms  a  most  valuable  liquid  manure  for  grass  land  and  for  crops  of  rising  corn  ;  or,  to  the 
acid  solution,  pearl  ashes  may  be  added,  and  the  whole  then  dried  up,  by  the  addition  of 
charcoal  powder  or  vegetable  mould,  till  it  is  sufficiently  dry  to  be  scattered  with  the  hand 
as  a  top  dressing,  or  buried  in  the  land  by  means  of  a  drill. 

In  France,  soup  is  extensively  made  by  dissolving  bones  in  a  steam  heat  of  two  or  three 
days'  continuance.  Respecting  the  nutritive  property  of  such  soup,  Liebig  has  expressed 
the  following  strong  opinion  : — "  Gelatine,  even  when  accompanied  by  the  savory  constitu- 
ents of  flesh,  is  not  capable  of  supporting  the  vital  process ;  on  the  contrary,  it  diminishes 
the  nutritive  value  of  food,  which  it  renders  insufficient  in  quantity  and  inferior  in  quality, 
and  it  overloads  the  blood  with  nitrogenous  products,  the  presence  of  which  disturbs  and 
impedes  the  organic  processes."  The  erroneous  notion  that  gelatine  is  the  active  principle 
of  soup,  arose  from  the  observation  that  soup  made,  by  boiling,  from  meat,  when  concen- 
trated to  a  certain  point,  gelatinizes.  The  jelly  was  taken  to  be  the  true  soup  until  it  was 
found  that  the  best  meats  did  not  yield  the  finest  gelatine  tablets,  which  were  obtained  most 
beautiful  and  transparent  from  tendons,  feet,  cartilage,  bones,  &c.  This  led  to  an  investiga- 
tion on  nutrition  generally,  the  results  of  which  proved  that  gelatine,  which  by  itself  is 
tasteless,  and  when  eaten  excites  nausea,  possesses  no  nutritive  value  whatever. 

The  following  table  exhibits  the  relation  between  the  combustible  animal  matter  and  the 
mineral  substances  of  bones,  as  found  by  different  observers  : — 


Organic  Portion. 

Inorganic  Portion. 

Observers. 

Ox  bones    -         -        - 

20 
2-1 

Berzelius. 
Marchand. 

2-0 

Berzelius. 

Human  bones    -         -     ■ 

1-8  to  2-3          ) 
2-0  in  mean      C 
1-6  to  2-2          1 

Frerichs. 

1-9  in  mean      |- 
2-3  to  2-0          ) 

Yon  Biria. 

Bird  bones 

Prior  to  the  use  of  bones  by  the  turner  or  carver,  they  require  the  oil  with  which  they 
are  largely  impregnated,  to  be  extracted,  by  boiling  them  in  water,  and  bleaching  them  in 
the  sun  or  otherwise.  This  process  of  boiling,  in  place  of  softening,  robs  them  of  part  of 
their  gelatine,  and  therefore  of  part  of  their  elasticity  and  contractibility  likewise,  and  they 
become  more  brittle. 

The  forms  of  the  bones  are  altogether  unfavorable  to  their  extensive  or  ornamental 
employment :  most  of  them  arc  very  thin  and  curved,  contain  large  cellular  cavities  for 
marrow,  and  are  interspersed  with  vessels  that  are  visible  after  they  are  worked  up  into 
spoons,  brushes,  and  articles  of  common  turnery.  The  buttock  and  shin  bones  of  the  ox 
and  calf  are  almost  the  only  kinds  used.  To  whiten  the  finished  works,  they  are  soaked  in 
turpentine  for  a  day,  boiled  in  water  for  about  an  hour,  and  then  pohshed  with  whitening 
and  water. 

noltzapfTcl  also  informs  us,  that  after  the  turning  tool,  or  scraper,  has  been  used,  bono  is 
polished,  1st,  with  glass  paper;  2d,  with  Trent  sand,  or  Flanders  brick,  with  water  on  flan- 
nel ;  3d,  with  whiting  and  water  on  a  woollen  rag  ;  4tli,  a  small  quantity  of  white  wax  is 
rubljcd  on  the  work  with  a  (juick  motion ;  the  wax  fills  the  minute  pores,  but  only  a  very 
minute  portion  should  be  allowed  to  remain  on  the  work.  Common  bone  articles,  such  as 
nail  an<l  tooth  brushes,  are  frequently  polished  with  slaked  lime  used  wet  on  flannel  or 
woollen  cloth.  See  "  On  Bone  and  its  Uses,"  by  Arthur  Aitkin,  Trans,  of  Bocidy  of  Arts, 
1832  and  1839. 

The  importance  of  the  trade  in  bones  will  be  seen  from  the  following  statement  of  Im- 
•ports,  in  1856,  of  the  bones  of  animals  and  fish — not  whalebone. 


BONE  BLACK. 


171 


Tods. 

Computed  real  Value. 

Russia 

Norway         

Denmark 

Prussia 

Hanover       

llanse  Towns 

Holland 

France          

Spain 

Tuscany        ...... 

Two  Sicilies 

Austrian  Italy 

Turkey  Proper      

United  States 

Brazil  ...---- 
Uruguay       ..---- 

Buenos  Ayres 

Australia       ...... 

Other  parts 

13,383 
'       878 

2,636 
826 
551 

4,073 

4,453 
881 
777 
787 
901 

1,968 
857 
589 

7,812 
15,457 

9,936 
837 

3,347 

£68,588 

4,500 
13,509 

4,233 

2,824 
20,874 
22,822              ' 

4,515 

3,982 

4,033 

4,618 
10,086 

4,392 

3,019 
40,036 
79,217 
50,922 

4,289 
17,154 

70,949 

£363,613 

In  1857,  of  bones,  whether  burnt  or  not,  or  as  animal  charcoal,  63,951  tons. — H.  M.  K 
BONE  BLACK.  The  composition  of  perfectly  dry  bone  black  of  average  quality  is  as 
follows: — Phosphate  of  lime,  with  carbonate  of  lime,  and  a  little  sulphuret  of  iron,  or  oxide 
of  iron,  88  parts  ;  iron  in  the  state  of  silicated  carburet,  2  parts  ;  charcoal  containing  about 
Vi5  of  nitrogen,  10  parts.  None  of  the  substances  present,  except  the  charcoal,  possess 
separately  any  decolorizing  power. 

It  was  formerly  supposed  that  the  peculiar  absorbing  and  decoloring  power  of  animal 
charcoal  was  only  e.\erted  towards  bodies  of  organic  origin  ;  but  it  was  found,  by  Graham, 
that  inorganic  substances  are  equally  subject  to  this  action ;  and  later  experiments  have 
demonstrated  that  there  are  few,  if  any,  chemical  compounds  which  altogether  resist  the 
absorbing  power  of  charcoal.  Tlie  action  is  of  a  mechanical  nature,  and  in  some  cases  it  is 
sufficiently  powerful  to  overcome  chemical  affinities  of  considerable  power.  It  is  not  con- 
fined to  charcoal,  though  pre-eminent  in  this  substance,  in  consequence  of  the  immense  ex- 
tent of  surface  which  its  porous  structure  presents.  The  action  of  charcoal  in  sugar  refining 
has  been  particularly  studied  by  Liidersdorf.  When  the  defecated  saccharine  juice  is 
allowed  to  flow  upon  a  moist  and  firmly  compressed  charcoal  filter,  pure  water  is  the  first 
product  that  passes  through  ;  but  a  considerably  larger  quantity  is  obtained  than  was  cm- 
ployed  for  moistening  the  charcoal.  Water  is  then  obtained  of  a  decidedly  saline  character, 
which  increases  in  strength,  and  after  this  has  passed  through  for  some  time,  a  sweet  taste 
becomes  perceptible,  which  gradually  increases,  and  at  last  entirely  masks  the  saline.  This 
purely  sweet  fluid  continues  to  flow  for  some  time ;  after  which,  the  liquid  acquires  an 
alkaline  reaction  from  the  presence  of  caustic  lime ;  it  then  becomes  colored,  the  liquor 
getting  gradually  darker,  till  the  action  of  the  charcoal  ceases.  Lime  is  completely 
abstracted  from  lime  water  by  bone  charcoal ;  and,  according  to  the  experiments  of  Cheval- 
lier,  lead  salts  are  likewise  entirely  absorbed,  the  acetate  the  most  readily.  It  has  also  been 
shown  by  Graham,  that  iodine  even  is  separated  from  iodine  of  potassium.  The  commercial 
value  of  animal  charcoal  has  usually  been  estimated  by  its  decoloring  power  on  sulphate  of 
indigo  ;  its  absorbent  power,  which  is  a  property  of  equal,  perhaps  of  greater  importarce, 
may,  according  to  M.  Corcnwinder,  bo  determined,  approximatively,  by  the  quantity  of  lime 
which  a  given  weight  will  absorb.  For  this  purpose  he  employs  a  solution  of  saccharate  of 
lime  of  known  strength.  An  acid  liquor  is  first  prepared,  composed  of  20  grammes  of  pure 
oil  of  vitriol  diluted  with  water  to  exactly  1  litre.  A  solution  of  saccharate  of  lime  is  then 
prepared,  by  dissolving  125  to  130  grammes  of  white  sugar  in  water,  adding  thereto  15  to 
20  grammes  of  quick-lime,  boiling  the  liciuid,  and  tlien  filtering  to  sei)arate  the  undissolved 
lime.  Tliis  solution  is  prepared  of  such  a  nature,  that  it  will  be  exactly  saturated  by  the 
same  volume  of  the  dilute  sulphuric  acid.  By  adding  the  latter  to  50  cul)ic  centimetres  of 
the  liquid  filtered  from  the  animal  charcoal,  it  is  easy  to  see  how  many  degrees  of  the 
burette  are  required  to  complete  the  saturation  of  the  lime.  Svippose  35  are  retpiired  for 
this  purpose,  100  —  35  =  65,  which  n^present  the  proportion  of  lime  ahsorl)ed  by  the  char- 
coal :  this  is,  therefore,  the  number  representing  the  standard.  By  operating  with  a  burette 
graduated  from  the  bottom,  the  degree  of  the  charcoal  experimented  upon  may  be  read 
directly. 


172  BOOKBINDING. 

BOOKBINDIXG.  The  process  of  sewing  together  the  sheets  of  a  book,  and  securing 
tbera  with  a  back  and  side  boards. 

Books  arc  said  to  be  either  stitched,  or  in  boards,  or  half-bound,  or  bound.  The  first 
consists  simply  of  stitcliing  the  sheets  together.  The  second,  Of  placing  the  sheets,  after 
they  have  been  stitched,  between  millboard  sides,  which  are  covered  with  paper -or  cloth, 
and  with  the  backs  lettered  and  ornamented.  The  third  is  a  process  of  more  perfectly  se- 
curing the  leaves,  and  of  placing  them  between  boards  with  a  back  of  leather,  the  side-boards 
being  covered  with  marble  paper.  Books  are  whole  bound  when  the  sides  as  well  as  the 
buck  are  covered  with  leather.  Bookbinding  is  performed  in  the  following  manner : — The 
sheets  are  first  folded  into  a  certain  number  of  leaves,  according  to  the  form  in  which  the 
book  is  to  appear,  as  follows  : — 

The  folio  consists  of-         -         -         -         -         -2  leaves 

"    quarto  of 4" 

"    octavo  of 8      " 

"    duodecimo  of        -         -         -         -         -         -12" 

AYhen  the  leaves  arc  thus  folded  and  arranged  in  proper  order,  they  are,  if  the  books 
have  been  long  printed,  usually  beaten  upon  a  stone  with  a  heavy  hammer,  to  make  them 
solid  and  smooth,  and  are  then  subjected  to  severe  pressure  in  a  powerful  press ;  but  in  the 
case  of  newly-printed  books,  pressure  alone  is  considered  sufficient.  Beating,  or  severe 
pressure,  would  spoil  the  book  ;  because  the  ink,  not  being  well  dried,  would  "  set  oft'"  on 
the  opposite  pages. 

The  employment  in  bookbinding  of  a  rolling-press  for  smoothing  and  condensing  the 
leaves,  instead  of  the  hammering  which  books  have  usually  received,  is  an  improvement 
introduced  several  years  ago  in  the  trade  by  Mr.  W.  Burn.  His  press  consists  of  two  iron 
cylinders  about  a  foot  in  diameter,  adjustable  in  the  usual  way  by  means  of  a  screw,  and 
put  in  motion  by  the  power  of  one  man,  or  of  two  if  need  be,  applied  to  one  or  two  winch- 
handles.  In  front  of  the  press  sits  a  boy  who  gathers  the  sheets  into  packets,  by  placing 
two,  three,  or  four  upon  a  piece  of  tin  plate  of  the  same  size,  and  covering  them  with  an- 
other piece  of  tin  plate,  and  thus  proceeding  by  alternating  tin  plates  and  bundles  of  sheets 
till  a  sufficient  quantity  has  been  put  together,  which  will  depend  on  the  stiffness  and 
thickness  of  the  paper.  The  packet  is  then  passed  between  the  rollers  and  received  by  the 
man  who  turns  the  winch,  and  who  has  time  to  lay  the  sheets  on  one  side  and  to  hand  over 
the  tin  plates  by  the  time  that  the  boy  has  prepared  a  second  packet.  A  minion  Bible  may 
be  passed  through  the  press  in  one  minute,  whereas  the  time  necessary  to  beat  it  would  be 
twenty  minutes.  It  is  not,  however,  merely  a  saving  of  time  that  is  gained  by  the  use  of 
the  rolling-press ;  the  paper  is  made  smoother  than  it  would  have  been  by  beating ;  and 
the  compression  is  so  much  greater,  that  a  rolled  book  will  be  reduced  to  about  five-sixths 
of  the  thickness  of  the  same  book  if  beaten.  A  shelf,  therefore,  that  will  hold  fifty  books 
bound  in  the  usual  way,  would  hold  nearly  sixty  of  those  bound  in  this  manner — a  circum- 
stance of  no  small  importance,  when  it  is  considered  how  large  a  space  even  a  moderate 
library  occupies,  and  that  book-cases  are  expensive  articles  of  furniture.  The  rolling-press 
is  now  substituted  for  the  hammer  by  our  principal  bookbinders. 

After  the  sheets  have  been  thus  prepared,  they  are  sewed ;  for  which  purpose  the  sew- 
ing press  is  employed.     See  Bookbindert,  Vol.  I. 

I30RACIC  ACID.  {Acide  Borujue,  Fr.  BO^ ;  chemical  equivalent,  34-9  ;  specific  grav- 
ity, 1  83.)  Supposed  to  be  the  chrifsocoUa  of  Pliny.  In  the  seventh  century,  Geber 
mentions  borax  ;  and  it  was  descril)cd  by  Geoffroy  and  by  Baron  in  the  early  part  of  the 
eighteenth  century.     Boracic  acid  was  formerly  called  Ilomberfi^s  sedative  salt. 

This  acid  occurs  in  several  minerals,  particularly  as  tincal,  or  crude  biborate  of  soda, 
which  is  found  in  the  form  of  incrustations  in  the  beds  of  small  lakes  in  Thibet,  where  it  is 
dug  up  during  the  hot  season.  Sassolin,  so  called  from  its  having  been  first  obtained  from 
one  of  the  localities  in  Tuscany  named  Sasso,  is  native  boracic  acid.  It  is  found  abundantly 
in  the  crater  of  Vulcano,  one  of  the  Lipari  Islands,  forming  a  layer  on  the  sulphur  and 
around  the  fumarolcs,  or  exits,  of  the  stilphurous  exhalations.  The  native  stalactitic  salt, 
according  to  Klaproth,  contains  mechanically  mixed  sulphate  of  magnesia  and  iron,  sulphate 
of  lime,  silica,  carbonate  of  lime,  and  alumina.  Erdmann  has  stated  that  sassolin  contains 
3-18  per  cent,  by  weight  of  anunonia,  and,  instead  of  being  pure  boracic  acid,  that  it  is  a  bo- 
rate of  ammonia.  Native  boracic  acid  is  composed  of  boracic  acid,  56-4  ;  water,  43-6. — 
iJatta. 

Professor  Graham,  in  his  "  Report  on  the  Chemical  Products  of  the  Great  Exhibition  of 
18.")!,"  thus  speaks  of  Larderel's  discovery  : — 

"  Tiic  preparation  of  boracic  acid  by  Cotmt  F.  do  Larderel,  of  Tuscany,  was  rewarded  by 
a  Council  medal.  Although  this  well-known  manufacture  is  not  recent,  having  attained  its 
full  development  at  least  ten  years,  still  the  bold  originality  of  its  first  conception,  the  per- 
severance and  extraordinary  resources  displayed  in  the  successful  establishment,  and  the 
value  of  the  product  which  it  supplies,  will  always  place  the  operations  of  Count  de  Larderel 


BORACIO  ACID. 


173 


among  the  highest  achievements  of  the  useful  arts,  and  demand  the  most  honorable  mention 
at-  this  epoch.  The  vapor  issuing  from  a  volcanic  soil  is  condensed,  and  the  minute  pro- 
portion of  boracic  acid  which  it  contains  (not  exceeding  0"3  per  cent.)  is  recovered  by 
evaporation,  in  a  district  without  fuel,  by  the  application  of  volcanic  vapor  itself  as  a  source 
of  heat.  The  boracic  acid  thus  obtained  greatly  exceeds  in  quantity  the  old  and  limited 
supply  of  borax  from  the  upper  districts  of  India,  and  has  greatly  extended  the  use  of  that 
salt  in  the  glazes  of  porcelain,  and  recently  in  the  making  of  the  most  brilliant  crystal,  when 
combined  with  the  oxide  of  zinc  instead  of  oxide  of  lead." — Reports  of  the  Jurors  of  the 
Great  Exhibition  of  I8bl. 

The  violence  with  which  the  scalding  vapors  escape  from  the  suffioni  gives  rise  to  muddy 
explosions  when  a  lake  has  been  drained  by  turning  its  waters  into  another  lake.  The  mud 
is  then  thrown  out,  as  solid  matters  are  ejected  from  volcanoes,  and  there  is  formed  in  the 
bottom  of  the  lake  a  crowd  of  little  cones  of  eruption,  whose  temperatures  when  in  activity 
and  play  are  generally  from  120^  to  145^  C,  and  the  clouds  which  they  form  in  the  lagv^ons 
constitute  true  natural  barometers,  whose  greater  or  less  density  rarely  disappoints  the 
predictions  that  they  announce  to  the  inhabitants  of  those  lagoons. 

The  boracic  acid  of  the  Tuscan  lagoons  is  obtained  from  nine  different  works  belonging 
to  Count  Larderel,  the  produce  of  which  is  on  the  average  as  follows  : — 


Sasso 
Larderello 
Lervazano 
Monte  Cerboli 
Castel  Nuovo 
Monte  Rotondo 
San  Frederigo 
Lustignauo     - 
Lago 


M.  Payen  has  given  the  following 
100  kilogrammes: — 


36,000  lbs. 

per  month 

32,700 

20,270 

19,125 

16,870 

16,850 

9,000 

7,640 

5,400 

163,855  avoirdupois  pounds, 
as  the  composition  of  this  crude  boracic  acid  for 


Pure  crystallized  boracic  acid 
Sulphate  of  ammonia 

"         of  magnesia 

"         of  lime 
Chloride  of  iron  - 
Alumina 
Sand,  &c.  ) 
Sulphur     ) 

Hygroscopic  water  disengaged  at  35°  C. 
Azotic  organic  matter  "         '  7 

Hydrochlorate  of  ammonia  -  >■ 

Hydrochloric  and  hydrosulphuric  acid  ) 


-  74  to  84 

-  14  to  8 

-  2-5  to  1-25 

-  7  to  5-75 

-  2-5  to  1 


The  processes  of  chemical  alteration  taking  place  beneath  the  crater  of  Vulcano, 
already  spoken  of,  may,  according  to  the  statement  of  Hoffmann,  depend  upon  conditions 
very  similar  to  those  existing  in  Tuscany.  There,  likewise,  sulphuretted  hydrogen  is 
associated  with  the  boracic  acid,  and,  it  would  appear,  in  much  greater  quantity,  since 
the  fissures  through  which  the  vapor  issues  are  thickly  lined  with  sulphur,  which  is  in 
sufficient  quantity  to  be  collected  for  sale.  A  profitable  factory  is  established  at  the 
place,  which  yields  daily,  besides  boracic  acid  and  chloride  of  ammonium,  about  1,700  lbs. 
of  refined  sulphur,  and  about  600  lbs.  of  pure  alum. — JBischof. 
In  1855  our  Imports  were  : — 

Cwts.  Computed  real  Value. 

Boracic  acid  from  Sardinia    -        -        85    -        -        -         £383 
"  "       Tuscany    -  26,777     -         -         -     121,163 

"  "      Gibraltar  -        -      947     -        -        -        4,285 


And  in  1856  :— 

27,809 

£125,831 

Boracic  acid  from  Sardinia    - 

Cwts. 
-       313     - 

Computed  re.il  Value. 
-      £1,377 

"                 "      Tuscany    - 

"      Peru 
"                "      other  parts 

25,003     - 

-    1,453     - 

1     - 

-     110,264 

6,394 

4 

26,830 


£118,039 


174  BORAX. 

BORAX.     {Borax,  Fr. ;  Borar,  Germ.)     Anhydrous  Borax  is  composed  of — 
1  equivalent  of  boracic  acid         -         -         -  872      or      69*0 

1  *'  soda 390       "       31-0 


Octahedral  Borax — 

1  equivalent  of  boracic  acid 
1         "  soda  - 

5         "  water 

Prismatic  Borax — 

1  equivalent  of  boracic  acid 
1  "  soda  - 

10         "  water 


1262    for     100-0 


872 

or 

47-7 

390 

" 

21-3 

662-5 

for 

31-0 

1824-5 

100-0 

872 

or 

36-55 

390 

(1 

16-35 

1-125 

(1 

47-1 

2-387    for    100-00 


Tincal  was  originally  brought  from  a  salt  lake  in  Thibet;  the  borax  was  dug  in  masses 
from  the  edges  and  shallow  parts  of  the  lake ;  and  in  the  course  of  a  short  time  the 
liolos  thus  made  were  again  tilled.  The  borate  of  soda  has  been  found  at  Potosi,  in  Peru; 
and  it  has  been  discovered  by  Mr.  T.  Sterry  Hunt,  of  the  Geological  Survey,  in  Canada, 
from  whose  report  the  following  extract  is  made : — 

"  In  the  township  of  Joly  there  occurs  a  very  interesting  spring  on  the  banks  of  the 
Ruisscau  Magnenat,  a  branch  of  the  Riviere  Souci,  about  five  miles  from  the  mills  of 
Methot  at  Saint  Croix.  The  spring  furnishes  three  or  four  gallons  a  minute  of  a  water 
which  is  sulphurous  to  the  taste  and  smell,  and  deposits  a  white  matter  along  its  channel, 
which  exhibits  the  purple  vegetation  generally  met  with  in  sulphur  springs.  The  tem- 
perature of  this  spring  in  the  evening  of  one  7th  of  July  was  46°  F.,  the  air  being  52°  F. 
The  water  is  not  strongly  saline,  but  when  concentrated  is  very  alkaline  and  salt  to  the 
taste.  It  contains,  besides  chlorides,  sulphates,  and  carbonates,  a  considerable  propor- 
tion of  boracic  acid,  which  is  made  evident  by  its  power  of  reddening  paper  colored  by 
turmeric,  after  being  supersaturated  with  hydi-ochloric  acid.  .  .  .  The  analysis  of 
1,000  parts  of  the  water  gave  as  follows: — 

Chloride  of  sodium 0-3818 

"  potassium  .-...-       0-0067 

Sulphate  of  soda 0-0215 

Carbonate  and  borate  of  do. 0.2301 

"  of  lime 0-0620 

"  magnesia        - 0-0257 

Silica 00245 

Alumina a  trace 


0-7523 
"The  amount  of  boracic  acid  estimated  was  found  to  be  equal  to  0-0279." 
Professor  Bechi  has  analyzed  a  borate  occurring  as  an  incrustation  at  the  Tuscan 
lagoons,  which  afforded  boracic  acid  43-50,  soda  19-25,  and  water  37-19.  Lagotiite  is  a 
mineral  of  an  earthy  yellow  color,  which  appears  to  be  boracic  acid  and  iron ;  while  Lar- 
dcrellite,  also  from  Tuscany,  is  a  compound  of  boracic  acid  and  soda.  See  Dana,  and 
"  American  Journal  of  Science." 

BORING.  The  importance  of  boring,  as  a  means  of  searching  for  coal  and  for  water, 
renders  it  necessary  that  some  special  attention  should  be  given  to  the  subject  in  a  work 
devoted  to  manufactures  and  mining. 

Boring  for  water  appears  to  have  been  in  use  from  the  earliest  periods,  in  Egypt  and 
in  Asia.  In  many  of  the  desert  tracts  there  are  remains  of  borings,  which  served,  evi- 
dently, at  one  period,  to  supply  the  wants  of  extensive  populations  which  once  inliabited 
those  now  deserted  regions.  In  the  "Guide  du  Sorideur,"  by  Jl.  J.  Degousec,  we  find  it 
stated,  with  reference  to  China,  "There  exists  in  the  canton  of  Ou-Tong-Kiao  many 
tliousand  wells  in  a  space  often  leagues  long  by  five  broad.  These  wells  cost  a  thousand 
and  some  hundred  taels,  (the  taiil  being  of  the  value  of  Cs.  &d.,)  and  are  from  1,500  to 
1,800  feet  deep,  and  about  0  inches  in  diameter.  To  bore  these  wells,  the  Chinese  com- 
mence by  placing  in  the  earth  a  wooden  tube  of  3  or  4  inches  diameter,  surmounted  by 
a  stone  edge,  pierced  by  an  orifice  of  5  or  6  inches;  in  the  tube  a  trepan  is  allowed  to 
play,  weighing  300  or  400  lbs.  A  man,  mounted  on  a  scaffold,  swings  a  block,  which 
raises  tlie  trepan  2  feet  high,  and  lets  it  fall  by  its  own  weight.  The  trepan  is  secured  to 
the  swing-lever  by  a  cord  made  of  reeds,  to  which  is  attached  a  triangle  of  wood ;  a  man 


BORING. 


175 


sits  close  to  the  cord,  and  at  each  rise  of  the  swing  seizes  the  triangle  and  gives  it  a  half 
turn,  so  that  the  trepan  may  take  in  falling  another  direction.  A  change  of  workmen 
goes  on  day  and  night,  and  with  this  continuous  labor  they  arc  sometimes  three  years  in 
boring  wells  to  the  requisite  depth." 

Boring  appears  to  have  been  practised  in  England  during  the  last  century,  but  to  a 
very  limited  extent;  it  has,  however,  for  a  considerable  period  been  employed  in  seeking 
for  coal,  and  in  the  formation  of  wells. 

The  ordinary  practice  of  boring  is  usually  carried  out,  by  first  sinking  a  well  of  such 
a  depth  that  the  boring  apparatus  can  be  fixed  in  it ;  and  thus  a  stage,  raised  from  the 
surface  of  the  ground,  is  dispensed  with.  A  stout  plank  floor,  well  braced  together  by 
planks  nailed  transversely  and  resting  on  putlocks,  forms  the  stage.  In  the  centre  of  the 
floor  is  a  square  hole,  through  which  the  boring-rods  pass.  The  boring-rods  are  of  many 
different  forms.     A  few  are  represented  in  the  following  figure,  (70.) 

1,  2,  3  ai'e  an  elevation,  plan,  and  section  of  an  auger;  the  tapped  socket  is  for  the 
purpose  of  allowing  the  rods  to  be  screwed  into  it. 

4,  5  are  two  views  of  a  small  auger,  with  a  longitudinal  slit,  and  no  valve,  which  is 
used  for  boring  through  clay  and  loam.  In  very  stiff  clay  the  slit  is  generally  made 
larger  ;  in  moist  ground  the  slit  is  objectionable. 

6,  7,  8  are  different  views  of  a  shell,  a  a  are  valves  opening  upwards,  to  admit  the 
material.  These  tools  are  used  for  boring  through  sand,  or  through  ground  which  has 
been  loosened  by  other  tools. 

9,  10,  11  show  an  S  chisel,  for  cutting  through  rocks,  flints,  and  the  like. 

Sucii  are  the  principal  tools  employed.  The  boring-rods  are  turned  round  by  the 
leverage  of  two  handles  moved  by  man,  or,  where  the  work  is  heavy,  by  horse,  or,  some- 
times, even  steam  power  is  applied.  Besides  the  circular  motion  of  the  tool,  a  vertical 
percussive  action  of  the  same  is  required  in  certain  cases,  such  as  rock  or  hard  sand ; 
indeed,  always,  where  the  position  of  the  auger  or  chisel  requires  a  fresh  place  to  act 
upon  during  its  revolution.  This  motion  is  most  readily  got  by  suspending  the  boring- 
rods  to  a  windlass,  through  the  intervention  of  a  rope  coiled  two  or  three  times  round 
the  latter,  and  adjusting  it  so  that  if  the  workman- holds  one  end  of  the  coil  tight,  suffi- 

70 


s. 

d. 

5 

6  per  fathom. 

11 

0 

16 

6          " 

22 

0 

176  BOEING. 

cicnt  will  be  the  friction  to  raise  the  rods  on  putting  the  windlass  in  motion.  Should  the 
end  of  the  rope  the  workman  holds  now  be  slackened,  the  coil  becomes  loose,  and  the 
rods  descend  with  a  force  equivalent  to  their  weight  and  the  distance  through  which  they 
have  fallen.  A  regular  percussive  action  is  thus  gained  by  keeping  the  windlass  contin- 
ually in  motion  in  one  direction,  the  attendant  workman  alternately  allowing  the  rods  to 
be  drawn  up  a  certain  distance,  and  then,  by  rela.xing  his  hold,  allowing  them  to  fall. — 
— Swindell,  on  Boring, 

Tlie  following  list  of  the  prices  of  boring,  in  different  localities,  may  prove  useful: — 

In  the  North  of  England,  the  prices  for  boring,  in  the  ordinary  strata  of  the  district 

or  of  that  coal  field,  are  as  follows  : — 

First      5  fathoms  .         -         -         . 

Second  5       "  .... 

Third    5       "  -         -         .         . 

Fourth  5       "  .... 

and  so  increasing  5s.  Cd.  per  fathom  on  each  succeeding  depth  of  5  fathoms.  "When  any 
unusually  hard  strata  are  met  with,  the  borer  is  paid  by  special  arrangement,  unless  a 
binding  contract  has  been  previously  made.  It  is  sometimes  usual  for  the  borer  to  take 
all  risk  of  hard  strata,  when  the  prices  are  as  follows,  the  borer  finding  the  tools: — 

s.     d. 

First      5  fathoms 7     6  per  fathom. 

Second  5       "  15     0  " 

Third     5       "  22     6  " 

Fourth  5        "  SO     0  " 

and  so  increasing  7s.  &d.  per  fathom  on  each  succeeding  depth  of  5  fathoms. 

In  the  Midland  Counties,  where  the  strata  are  more  inclined  than  in  the  north  of  Eng- 
land, the  prices  for  ordinary  strata  are  as  follows : — 

First  20  yards     -      .  - 

Next  10     " 

"    10    " 

"    10    " 

"    10    " 

and  so  advancing  Is.  Gd.  per  yard  upon  each  10  yards. 

In  some  localities,  where  the  boring  is  still  more  favorable,  the  prices  are  as  follows, 
— the  bore  hole  being  2^  to  2|  inches  diameter : — 

First  20  yards 

Next  10     " 

"     10     " 

"    10    " 

"    10    " 

In  boring  strata  of  unusual  hardness,  a  special  arrangement  is  made,  as  before  stated, 
and  the  borer  is  allowed  some  payment  for  filling  up  and  for  removing  tackUng, 
In  Scotland  the  general  prices  for  boring  are  as  follows  : — 

s.     d. 

First      5  fathoms 5     0  per  fathom 

Second  5       "  10     0  " 

Third     5        "  15     0  " 

Fourth  5       "  20     0  " 

and  so  advancing  5s.  per  fathom  for  each  succeeding  5  fathoms. 

In  boring  through  very  hard  strata,  the  work  is  done  either  by  shaft-work,  or  at  the 
following  rates,  the  bore  hole  being  2f  inches  diameter : — 

s.     d. 
First      5  fathoms       .... 
Second  5       "  .... 

Third     5       "  .... 

The  borer  usually  specifies  to  have  his  tackle  laid  down  ready  for  erecting  at  the  cost 
of  the  employer. 

As  the  boring  proceeds,  it  is  often  necessary  to  lower  pipes  into  the  hole  made,  to  pre- 
vent the  falling  of  fragments  from  the  sides  of  the  cylinder.  There  are  many  ingenious 
contrivances  for  effecting  this,  which  need  not  be  described  in  this  place.  See  Pit 
Coal,  vol.  i. 


s. 

d. 

3 
5 

6  per  yard 
0 

6 

6 

8 

0 

9 

6 

s. 

d. 

3 

6  per  yard 

4 

6 

5 

6         " 

6 

6 

1 

6 

10 

0 

per 

fathom. 

20 

0 

u 

SO 

0 

(( 

BRASS. 


irr 


BORON.  One  of  the  non-metallic  elements ;  it  exists  in  nature  in  the  form  of  boracic 
acid,  and  as  borax,  tincal,  &c. 

Homberg  is  said  to  have  obtained  boron  from  borax  in  1702  ;  if  so,  his  discovery  appears 
to  have  been  forgotten,  since  it  was  unknown,  except  hypothetically,  to  the  more  modern 
chemists  until,  in  1808,  it  was  obtained  by  Gay-Lussac  and  Thenard,  and  by  Davy  in  1808, 
who  decomposed  boracic  acid  into  boron  and  oxygen. 

Boron  is  best  obtained  by  preparing  the  double  fluoride  of  boron  and  potassium, 
(3KF  2BF^,)  by  saturating  hydrofluoric  acid  with  boracic  acid,  and  then  gradually  adding 
fluoride  of  potassium.  The  difficultly  soluble  double  compound  thus  produced  is  collected 
and  dried  at  a  temperature  nearly  approaching  to  redness.  This  compound  is  then  powdered 
and  introduced  into  an  iron  tube  closed  at  one  end,  together  with  an  equal  weight  of  potas- 
sium, whereupon  heat  is  apphed  sufficient  to  melt  the  latter,  and  the  mixture  of  the  two 
substances  is  eflfected  by  stirring  with  an  iron  wire.  Upon  the  mass  being  exposed  to  a  red 
heat,  the  potassium  abstracts  the  fluorine.  The  fluoride  of  potassium  may  afterwards  be 
removed  by  heating  the  mass  with  a  solution  of  chloride  of  ammonium,  which  converts  the 
free  potassa  into  chloride  of  potassium,  and  thus  prevents  the  oxidation  of  the  boron,  which 
takes  place  in  the  presence  of  fixed  alkali ;  the  chloride  of  ammonium  adhering  to  the 
boron  may  be  afterwards  removed  by  treatment  with  alcohol.  Boron  is  a  dark  greenish- 
brown  powder,  tasteless,  and  inodorous ;  its  chemical  equivalent  is  10-9,  or,  according  to 
Laurent,  11  "0. 

BOTTLE  MANUFACTURE.     See  Glass  and  Pottery. 

BOULDERING  STONE.  A  name  given  by  the  Sheffield  cutlers  to  the  smooth  flint 
pebbles  with  which  they  smooth  down  the  faces  of  buff  and  wooden  wheels.  As  these 
stones  are  usually  taken  from  gravel  pits,  the  name  is,  no  doubt,  used  in  the  same  sense 
as  the  geologist  uses  the  word  boulder. 

BOX  WOOD.  {Buis^  Fr.  ;  Buchsbawn,  Germ. ;)  Buxus  scmpervirens.—liwo  varieties 
of  box  wood  are  imported  into  this  country.  The  European  is  brought  from  Leghorn,  Por- 
tugal, &c. ;  and  the  Turkey  box  wood  from  Constantinople,  Smyrna,  and  the  Black  Sea. 
English  box  wood  grows  plentifully  at  Box  Hill,  in  Surrey,  and  in  Gloucestershire.  The 
English  box  wood  is  used  for  common  turnery,  and  is  preferred  by  brass  finishers  for  their 
latlie-chucks,  as  it  is  tougher  than  the  foreign  box,  and  bears  rougher  usage.  It  is  of  very 
slow  growth,  as  in  the  space  of  25  years  it  will  only  attain  a  diameter  of  1^  to  2  inches. 
— Holt~apffel. 

Box  wood  is  used  for  making  clarionets  and  flutes,  carpenters'  rules,  and  drawing  scales. 
As  the  wood  is  peculiarly  free  from  gritty  matter,  its  sawdust  is  used  for  cleaning  jewellery. 
Box  wood  is  exclusively  emptoyed  by  the  wood  engraver.     See  Engraving  on  Wood. 

A  similar  wood  was  imported  from  America  by  the  name  of  Tiigmutton,  which  was  used 
for  making  ladies'  fans  ;  but  we  cannot  learn  that  it  is  now  employed. 

BRASS.  The  table  on  the  following  page,  for  the  compilation  of  which  we  are  indebted 
to  Mr.  Robert  Mallet,  C.  E.,  presents,  in  a  very  intelligible  form,  the  chemical  and  physical 
conditions  of  the  various  kinds  of  brass  : — 

Brass  Color,  for  staining  glass,  is  prepared  by  exposing  for  several  days  thin  plates  of 
brass  upon  tiles  in  the  leer,  or  annealing  arch  of  the  glass  house,  till  they  are  oxidized  into 
a  black  powder,  aggregated  in  lumps.  This  being  pulverized  and  sifted,  is  to  be  again  well 
calcined  for  several  days  more,  till  no  particles  remain  in  the  metallic  state,  when  it  will 
form  a  fine  powder  of  a  russet-brown  color.  A  third  calcination  must  now  be  given  with  a 
carefully  regulated  heat,  its  quality  being  tested  from  time  to  time  by  fusion  with  some 
glass.  If  it  makes  the  glass  swell  and  intumesce,  it  is  properly  prepared  ;  if  not,  it  must  be 
still  further  calcined.  Such  a  powder  communicates  to  glass  greens  of  various  tints,  passing 
into  turquoise. 

When  thin  narrow  strips  of  brass  are  stratified  with  sulphur  in  a  crucible  and  calcined 
at  a  red  heat,  they  become  friable  and  may  be  reduced  to  powder.  This  being  sifted  and 
exposed  upon  tiles  in  a  rcverberatory  furnace  for  10  or  12  days,  becomes  fit  for  use,  and  is 
capable  of  imparting  a  chalcedony — red  or  yellow — tinge  to  glass  by  fusion,  according  to 
the  mode  and  proportion  of  using  it. 

The  glassmakers'  red  color  may  be  prepared  by  exposing  small  plates  of  brass  to  a  mode- 
rate heat  in  a  rcverberatory  furnace  till  they  are  thoroughly  calcined,  when  the  substance 
becomes  pulverulent,  and  assumes  a  red  color.     It  is  then  ready  for  immediate  use. 

Mr.  Holtzapff'el,  in  liis  "  Mechanical  Manipulation,"  has  given  some  very  important 
descriptions  of  alloys.  From  his  long  experience  in  manufacture,  no  one  was  more  capable 
than  Mr.  Iloltzapffel  to  speak  with  authority  on  the  alloys  of  copper  and  zinc.  From  his 
work  the  following  particulars  have  been  obtained  : — 

The  red  color  of  copper  slides  into  that  of  yellow  brass  at  aljout  4  or  5  ounces  of  zinc  to 
the  pound  of  copper,  and  remains  little  altered  unto  about  8  or  10  ounces ;  after  this  it 
becomes  whiter,  and  when  32  ounces  of  zinc  are  added  to  1 0  of  copper,  the  mixture  has  the 
brilli;mt  silvery  color  of  speculum  metal,  but  with  a  bluish  tint. 

These  alloys — from  about  8  to  1(5  ounces  to  the  pound  of  copper — are  extensively  used 
Vol.  in.— 12 


178 


BRASS. 


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BRAZIL  WOOD. 


179 


for  dipping,  a  process  adopted  for  giving  a  fine  color  to  an  enormous  variety  of  furniture 
work.  The  alloys  with  zinc  retain  their  malleability  and  ductility  well  unto  about  8  or  10 
ounces  to  the  pound ;  after  this  the  crystalline  character  slowly  begins  to  prevail.  The 
alloy  of  2  zinc  and  1  copper  may  be  crumbled  in  a  mortar  when  cold.  In  the  following  list, 
the  quantity  of  zinc  employed  to  1  lb.  of  copper  is  given  : — 

1  to  1^  oz.  gilding  metal  for  common  jewellery. 

3  to  4  oz.  Bath  metal,  pinchbeck,  Mannheim  gold,  Similor ;  and  alloys  bearing  various 

names,  and  resembling  inferior  jewellers'  gold. 
8  oz.  Emerson's  patent  brass. 
IOV5  oz.  Muntz's  metal,  or  40  zinc  and  60   copper.      "  Any  proportion,"  says  the 

patentee,  "  between  the  extremes,  50  zinc  and  50  copper  and  37  zinc  and  63  copper, 

will  roll  and  work  well  at  a  red  heat." 
16  oz.  soft  spelter  solder,  suitable  for  ordinary  brass  work. 
1 6^  oz.  Hamilton  and  Parker's  patent  mosaic  gold. 

Brass  is  extensively  employed  for  the  bearings  of  machinery.  Several  patents  have  been 
taken  out  for  compositions  varying  but  slightly.  The  following,  for  improvements  in  cast- 
ing the  bearings  and  brasses  of  machinery,  appears  important : — Mr.  W.  Hewitson,  of  Leeds, 
directs,  in  his  patent,  that  the  proper  mixture  of  alloy,  copper,  tin,  and  zinc,  should  be  run 
into  metal  or  "  chill "  moulds,  in  place  of  the  ordinary  mould.  In  large  castings,  it  is 
found  more  especially  that  the  metals  do  not  mix  intimately  in  cooling,  or,  rather,  they  ar- 
range themselves  into  groups  when  cast  in  sand,  and  the  bearings  are  found  to  wear  out 
more  quickly ;  but  if  the  bearings  are  cast  so  that  the  alloy  comes  in  contact  with  metal, 
the  mixture  is  more  intimate,  and  the  bearings  last  longer  than  if  cast  in  dry  or  green  sand 
moulds. 

Mr.  Hewitson  generally  only  applies  these  chill-metal  surfaces  of  the  moulds  to  those 
parts  of  a  brass,  or  bearing,  that  are  to  receive  the  shaft  or  bear  the  axis  of  a  machine.  The 
chills  are  preferred  of  iron,  perforated  with  holes  ('/is  to  Vs  inch)  for  the  passage  of  air  or 
vapors ;  the  surface  should  be  thinly  coated  with  loam,  and  heated  to  about  200 '. 

Fenton's  patent  metal  consists  of  copper,  spelter,  and  tin  ;  it  has  less  specific  gravity 
than  gun  metal,  and  is  described  as  being  "  of  a  more  soapy  nature,"  by  which,  conse- 
quently, the  consumption  of  oil  or  grease  is  lessened. 

Many  of  the  patentees  of  bearing-metals  assure  us  that  the  metals  they  now  use  differ 
very  considerably  from  the  statement  in  their  specifications.  Surely  this  requires  a  careful 
examination. 

We  exported  of  our  brass  manufactures,  in  1856,  19,198  cwts.,  the  declared  real  value 
of  which  was  £121,206. 

BRASSIXG  IRON.  Iron  ornaments  are  covered  with  copper  or  brass  by  properly 
preparing  the  surface,  so  as  to  remove  all  organic  matter,  which  would  prevent  adhesion, 
and  then  plunging  them  into  melted  brass.  A  thin  coating  is  thus  spread  over  the  iron,  and 
it  admits  of  being  polished  or  burnished.  The  electro-magnetic  process  is  now  employed 
for  the  purpose  of  precipitating  brass  on  iron.  This  process  was  first  mentioned  in  Shaw's 
"  Metallurgy,"  in  1844,  where  he  remarks,  "  In  depositing  copper  upon  iron,  a  solution  of 
the  cyanide  or  acetate  of  copper  should  be  employed.  The  only  value  of  these  salts  is,  that 
a  die  or  surface  of  iron  may  be  immersed  in  their  solutions  without  receiving  injury  by  the 
corrosion  consequent  upon  the  deposition  of  a  film  of  metal  by  chemical  action."  The  fol- 
lowing solutions  are  recommended  by  Dr.  Woods,  in  the  "  Scientific  American,"  for  coat- 
ing iron  with  copper,  iron,  or  brass,  by  the  electrotype  process  : — 

To  make  a  Solution  of  Copper  or  Zinc. — Dissolve  8  ounces  (troy)  cyanide  of  potassium 
and  3  ounces  of  cyanide  of  copper  or  zinc  in  1  gallon  of  rain  or  distilled  water.  These  solu- 
tions to  be  used  at  about  160°  F.  with  a  compound  battery  of  from  3  to  12  cells. 

To  prepare  a  Solution  of  Brass. — Dissolve  1  lb.  (troy)  cyanide  of  potassium,  2  ounces 
of  cyanide  of  copper,  and  1  ounce  of  cyanide  of  zinc,  in  1  gallon  of  rain  or  distilled  water  ; 
then  add  2  ounces  of  muriate  of  ammonia.  This  solution  is  to  be  used  at  160°  F.  for 
smooth  work,  and  from  90°  to  120°,  with  a  compound  battery  of  from  3  to  12  cells.  See 
Electro-Met.\li.urgy. 

BRAZIL  WOOD.  The  ibiripitanr/a,  or  Brazil  wood,  called,  in  Pernambuco,  pao  da 
rainha,  (Queen's  wood,)  on  account  of  its  being  a  Government  monopoly,  is  now  rarely  to  be 
seen  within  many  leagues  of  the  coast,  owing  to  the  improvident  nianiior  in  which  it  has 
been  cut  down  by  the  Government  agents,  without  any  regard  l)fing  jiaid  to  the  size  of  the 
tree  or  its  cultivation.  It  is  not  a  lofty  tree.  At  a  short  distance  from  the  ground,  innu- 
merable branches  spring  forth  and  extend  in  every  direction  in  a  straggling,  irregular,  and 
unpleasing  manner.  The  leaves  are  small  and  not  luxuriant ;  the  wood  is  very  hard  and 
heavy,  takes  a  high  polish,  and  sinks  in  water :  the  only  valuable  portion  of  it  is  the  heart, 
as  the  outward  coat  of  wood  has  not  any  peculiarity.  The  name  of  this  wood  is  derived 
from  brasas,  a  glowing  fire  or  coal ;  its  botanical  name  is  Cmsalpinin  Brnsileto.  The  leaves 
are  pinnated,  the  flower  white  and  papilionaceous,  growing  in  a  pyramidal  epikc;  one  spe- 


180  BEE  AD. 

cies  has  flowers  variegated  with  red.     The  branches  are  slender  and  full  of  small  prickles. 
There  are  nine  species.     See  Bell's  "  Geography." 

The  species  Brasileto,  which  is  inferior  to  the  crista,  grows  in  great  abundance  in  the 
West  Indies.  The  demand  for  the  Brasileto,  a  few  years  ago,  was  so  great,  owing  to  its 
bein"'  a  little  cheaper  than  the  crista,  that  nearly  the  whole  trees  in  the  British  possessions 
were  cut  down  and  sent  home,  which  Mr.  Bell  very  justly  terms  improvidence.  It  is  not 
now  so  much  used,  and  is  consequently  scarcer  in  the  English  market. 

The  wood  known  in  commerce  as  Pernambuco  is  most  esteemed,  and  has  the  greatest 
quantity  of  coloring  matter.  It  is  hard,  has  a  yellow  color  when  newly  cut,  but  turns  red 
by  exposure  to  the  air.  That  kind  termed  Lima  tvood  is  the  same  in  quality.  Sapan  wood 
grows  in  Japan,  and  in  quality  is  next  the  two  named  above.  It  is  not  plentiful,  but  is 
much  valued  in  the  dyehouse  for  red  of  a  certain  tint ;  it  gives  a  very  clear  and  superior 
color.  The  quantity  of  ash  that  these  two  qualities  of  wood  contain  is  worthy  of  remark. 
Lima  wood,  as  imported,  gives  the  average  of  2*7  per  cent.,  while  Sapan  wood  gives  1"5 
per  cent.  ;  in  both,  the  prevailing  earth  is  lime.  The  quantity  of  moisture  in  the  wood 
averages  about  10  per  cent.  ;  that  in  the  ground  wood  in  the  market  about  20  per  cent. 

Peach  wood,  or  Nicaragua,  and  sometimes  termed  Sa7ita  Martha  wood,  is  inferior  to  the 
other  two  named,  but  is  much  used  in  the  dyehouse,  and,  for  many  shades  of  red,  is  pre- 
ferred, although  the  coloring  matter  is  not  so  great.  It  gives  a  bright  dye.  The  means  of 
testing  the  quality  of  these  woods  by  the  dyer  is  similar  to  that  describey  for  logwood,  with 
the  same  recommendations  and  precautions. — Napier  on  Diieing. 

BREAD.  One  of  the  most  important,  if  not  altogether  the  most  important,  article  of 
food,  unquestionably,  is  bread  ;  and  although  rye,  barley,  oats,  and  other  cereals  are  some- 
times used  by  the  baker,  wheat  is  the  grain  which  is  best  fitted  for  the  manufacture  of  that 
article,  not  only  on  account  of  the  larger  amount  of  gluten,  or  nitrogenous  matter,  which  it 
contains,  and  than  can  be  found  in  other  edible  grains,  but  also  on  account  of  the  almost 
exact  balance  in  which  the  nitrogenous  and  non-nitrogenous  constituents  exist  in  that  cereal, 
and  owing  to  which  it  is  capable  of  ministering  to  all  the  requirements  of  the  human  frame, 
and  of  being  assimilated  at  once  and  without  effort  by  our  organs,  whence  the  name  of 
"  staff  of  life,"  which  is  often  given  to  it,  wheat  being,  like  milk,  a  perfect  food. 

Although  gluten  is  one  of  the  most  important  constituents  of  wheat,  the  imtritive  power 
of  its  flour,  and  its  value  as  a  bread-making  material,  should  not  be  altogether  considered 
as  dependent  upon  the  quantity  of  gluten  it  may  contain,  even  though  it  be  of  the  best 
quality.  Doubtless  a  high  percentage  of  this  material  is  desirable,  but  there  are  other 
considerations  which  must  be  taken  into  account ;  for,  in  order  to  become  available  for 
making  good  bread,  flour,  in  addition  to  being  sound  and  genuine,  must  possess  other  qualities 
beyond  containing  merely  a  large  amount  of  gluten.  Thus,  for  example,  the  bU  ronye  glace 
d^-Utvcrcfne,  which  contains  hardly  45  per  cent,  of  starch,  and  as  much  as  86  per  cent,  of 
gluten,  though  admirably  adapted  for  the  nianufacture  of  macaroni,  vermicelli,  semolina, 
and  other  pates  d'ltalie,  is  totally  unfit  for  making  good  bread  ;  the  flour  used  for  making 
best  white  loaves  containing  only  from  10  to  18  per  cent,  of  gluten,  and  from  60  to  70  per 
cent,  of  starch. 

Bread  is  obtained  by  baking  a  dough,  previously  fermented  either  by  an  admixture  of 
yeast  or  leaven,  or  it  is  artificially  rendered  spongy  by  causing  an  acid,  muriatic  or  tartaric, 
to  react  upon  carbonate  or  bicarbonate  of  soda,  or  of  ammonia,  mixed  in  the  doughy  mass ; 
or,  as  in  Dr.  Daugiish's  process,  which  will  be  described  further  on,  by  mixing  the  flour 
which  has  to  be  converted  into  dough,  not  with  ordinary  water,  but  with  water  strongly  im- 
pregnated with  carbonic  acid. 

The  conversion  of  flour  into  bread  includes  two  distinct  operations — namely,  the  prepa- 
ration of  the  dough,  and  the  baking.  The  preparation  of  the  dough,  however,  though 
reckoned  as  one,  consists,  in  fact,  of  three  operations — namely,  hydrating,  kneadiiig,  and 
fennentiiiri. 

When  the  baker  intends  to  make  a  batch  of  bread,  his  first  care  is,  in  technical  lan- 
guage, to  stir  a  fcrmpiit.  This  is  done,  in  London,  by  boihng  a  few  potatoes,  in  the  pro- 
portion of  5  lbs.  or  G  lbs.  of  potatoes  per  sack  of  flour,  (which  is  the  quantity  we  shall  assume 
it  is  desired  to  convert  into  bread,)  peeling  them,  mashing  and  straining  them  through  a 
cullender,  and  adding  thereto  about  three-quarters  of  a  pailful  of  water,  2  or  3  lbs.  of  flour, 
and  one  quart  of  yeast.  The  water  employed  need  not  be  warmed  beforehand,  for  the  heat 
of  the  potatoes  is  sufficient  to  inipnrt  a  proper  temperature  (from  70'  to  90°  F.)  to  the 
liquid  mass,  which  sliould  be  well  stirred  up  with  the  hand  into  a  smooth,  thin,  and  homo- 
geneous paste,  and  then  left  at  rest. 

In  the  course  of  an  hour  or  two,  the  mass  is  seen  to  rise  and  fall,  which  swelling  and 
heaving  up  is  due  to  carbonic  acid,  generated  by  the  fermentjition  induced  in  the  mass, 
which  may  be  thus  left  until  wanted.  In  about  three  hours,  this  fermenting  action  will 
appear  to  be  at  an  end,  and  when  it  has  arrived  at  that  stage,  it  is  fit  to  ))e  used.  The  fer- 
ment, however,  may  be  left  for  six  or  seven  hours  and  be  still  very  good  at  the  end  of  that 
time,  but  the  common  practice  is  to  use  it  within  four  or  five  hours  after  its  preparation. 


BREAD.  181 

The-  next  operation  consists  in  "  setting  the  sponged  This  consists  in  stirring  the  fer- 
ment well,  adding  thereto  about  two  gallons  of  lukewarm  water,  and  as  much  flour  as  will 
make,  with  the  ferment,  a  rather  stiff  dough.  This  constitutes  "  the  sponged  It  is  kept  in 
a  warm  situation,  and  in  the  course  of  about  an  hour,  fermentation  again  begins  to  make  its 
appearance,  the  mass  becomes  distended  or  is  heaved  up  by  the  carbonic  acid  produced,  the 
escape  of  wliich  is  impeded  by  the  toughness  of  the  mass.  This  carbonic  acid  is  the  result 
of  the  fermentation  induced  under  the  influence  of  water,  by  the  action  of  the  gluten  upon 
the  starch  a  portion  of  which  is  converted  thereby  into  sugar,  and  then  into  alcohol.  A 
time  however  soon  comes  when  the  quantity  of  carbonic  acid  thus  pent  up  becomes  so  great 
that  it  bursts  throuo'h,  and  the  sponge  collapses  or  drops  down.  This  is  called  the  Jirst 
sponge  ;  but  as  the  fermentation  is  still  going  on,  the  carbonic  acid  soon  causes  the  sponge 
to  rise  again  as  before  to  nearly  twice  its  volume,  when  the  carbonic  acid,  bursting  through 
the  mass  causes  it  to  fall  a  second  time  ;  and  this  constitutes  what  the  bakers  call  the  second 
sponge.  The  rising  and  falling  might  then  go  on  for  twenty-four  hours  ;  but  as  the  alco- 
holic would  pass  into  tiie  acetous  fermentation  soon  after  the  second  rising,  the  baker  always 
interferes  after  the  second,  and  very  frequently  after  the  first  sponge.  The  bread  made 
from  the  first  sponge  is  generally  sweeter ;  but,  unless  the  best  flour  is  used,  and  even  then, 
the  loaf  that  is  made  from  it  is  smaller  in  size  and  more  compact  than  that  which  is  made 
with  the  second  sponge.  In  hot  weather,  however,  as  there  would  be  much  danger  of  the 
bread  turning  sour,  if  the  sponge  were  allowed  to  "  take  a  second  full"  the  first  sponge  is 
frequently  used.  The  next  process  consists  in  breaking  the  sponge.,  which  is  done  by  adding 
to  it  the  necessary  quantity  of  water  and  of  salt, — the  quantity  of  the  latter  substance  vary- 
ing from  ^  lb.  to  f  of  a  pound  per  bushel  of  flour ;  that  is,  from  2;V  lbs.  to  3f  lbs.  per  sack 
of  flour,  (new  flour,  or  flour  of  inferior  quality,  always  requires,  at  the  very  least,  3^  lbs.  per 
sack,  to  bind  it,  that  is  to  say,  to  render  the  dough  sufficiently  firm  to  support  itself  while 
fermenting.)  Salt  acts,  to  a  great  extent,  like  alum,  though  not  so  powerfully.  As  to  the 
quantity  of  water  to  be  used,  it  depends  also  a  great  deal  on  the  quality  of  the  flour,  the 
best  quality  absorbing  most ;  though,  as  we  shall  have  occasion  to  remark,  the  baker  too 
often  contrives  to  force  and  keep  into  bread  made  from  inferior  flour,  by  a  process  called 
under-baking,  the  same  amount  of  water  as  is  normally  taken  up  by  that  of  the  best  quality. 
Generally  speaking,  and  with  flour  of  good  average  quality,  the  amount  of  water  is  such  that 
the  diluted  sponge  forms  about  14  gallons  of  liquid.  The  whole  mass  is  then  torn  to  pieces 
by  the  hand,  so  as  to  break  any  lumps  that  there  may  be,  and  mix  it  up  thoroughly  with  the 
water.  This  being  done,  the  rest  of  the  sack  of  flour  is  gradually  added  and  kneaded  into  a 
dough  of  the  proper  consistency.  This  kneading  of  the  dough  may  be  said  to  be  one  of 
the  most  important  processes  of  the  manufacture,  since  it  not  only  produces  a  more  com- 
plete hydration  of  the  flour,  but,  by  imprisoning  a  certain  quantity  of  air  within  the  dough, 
and  forcibly  bringing  into  closer  contact  the  molecules  of  the  yeast  or  leaven  with  the  sugar 
of  the  flour,  and  also  with  a  portion  of  the  starch,  the  fermentation  or  rising  of  the  whole 
mass,  on  which  the  sponginess  of  the  loaf  and  its  digestibility  subsequently  depend,  is  se- 
cured. When,  by  forcing  the  hand  into  the  dough,  the  baker  sees  that,  on  withdrawing  it, 
none  of  the  dough  adheres  to  it,  he  knows  that  the  kneading  is  completed.  The  dough  is 
then  allowed  to  remain  in  the  trough  for  about  an  hour  and  a  half  or  two  hours,  if  brewers^ 
or  German  yeast  have  been  employed  in  making  the  sponge ;  if,  on  the  contrary,  patent 
yeast  or  hop  yeast  have  been  used,  three  or  even  four  hours  may  be  required  for  the  dough 
to  rise  up,  or,  as  in  technical  language,  to  give  proof.  When  the  dough  is  sufficiently 
'■'■proofed"  it  is  weighed  oft" into  lumps,  shaped  into  the  proper  forms,  of  4  lbs.  4  oz.  each, 
and  exposed  for  about  one  hour  in  an  oven  to  a  temperature  of  about  570°  F.,  the  heat 
gradually  falling  to  430  or  420°  F.  The  yield  after  baking  is  94  quartern  (not  4-lb.)  loaves, 
or  from  90  to  92  really  4-lb.  loaves,  as  large  again  as  they  were  when  put  into  the  oven  in 
the  shape  of  dough. 

The  manner  in  which  yeast  acts  upon  the  flour  is,  as  yet,  an  unsolved  mystery,  or,  at 
any  rate  an,  as  yet,  unsatisfactorily  explained  action  ;  for  the  term  "  catalysis,"  which  has 
sometimes  been  applied  to  it,  explains  absolutely  nothing. 

A  yeast,  or  fermenting  material,  may  be  prepared  in  various  ways ;  but  only  three  kinds 
of  yeast  are  used  by  bakers  :  namely,  brewers'  yeast,  or  barm, — German  yeast,  and  patent, 
or  hop  yeast. 

The  most  active  of  these  ferments  is  the  first,  or  brewers'  yeast ;  it  is,  as  is  well  known, 
a  frothy,  thickish  material,  of  a  brownish  or  drab  color,  which,  when  recent,  is  in  a  state  of 
slight  effervescence,  exhales  a  sour  characteristic  odor,  and  has  an  acid  reaction. 

When  viewed  through  the  micro.scope,  it  is  seen  to  consist  of  small  globules  of,  various 
size,  generally  egg-shaped.     They  were  first  described  by  M.  Desmayieres. 

The  best,  and  in  fact  the  only  brewers'  yeast  used  in  bread-making,  is  that  from  the  ale 
breweries ;  porter  yeast  is  unavailable  for  the  purpose,  because  it  imparts  to  the  bread  a  dis- 
agreeable bitter  taste. 

German  yeast  is  very  extensively  used  by  bakers.  It  is  a  pasty  but  easily  crumbled 
mass,  of  an  agreeable  fruity  odor,  and  of  a  dingy  white  color.     German  yeast  will  remain 


182  BREAD. 

good  for  a  few  weeks,  if  kept  in  a  cool  place.  When  in  good  condition,  it  is  an  escellent 
article  •  but  samples  of  it  are  occasionally  seized  on  bakers'  premises,  of  a  darker  color,  vis- 
cid, and  emitting  an  offensive  cheesy  odor :  such  German  yeast,  being  in  a  putrefied  state, 
is,  of  course,  objectionable. 

The  so-called  "-patent  yeast"  is  the  cheapest  and  at  the  same  time  the  weakest  of  these 
ferments ;  very  good  bread,  however,  is  made  with  it,  and  it  is  most  extensively  used  by 
bakers.  It  is  made  either  with  or  without  hops  :  when  with  hops,  it  is  called  hop  yeast,  and 
is  nothing  more  than  a  decoction  of  hops  to  which  malt  is  added  while  in  a  scalding  hot 
state  ;  wlien  the  licjuor  has  fallen  to  a  blood  heat,  a  certain  quantity  of  brewers'  or  German 
yeast  is  thoroughly  mixed  with  it,  and  the  whole  is  left  at  rest.  The  use  of  the  hops  is  in- 
tended to  diminish  the  tendency  of  this  solution  to  become  acid. 
Potato  yeast  is  a  kind  of  ''patent  yeast  "  in  general  use. 

The  theory  of  panilieation  is  not  dithcult  of  comprehension.  "  The  flour,"  says  Dr.  Ure, 
"  owes  this  valuable  quality  to  the  gluten,  which  it  contains  in  greater  abundance  than  any 
of  the  other  cerealia,  (kinds  of  corn.)  This  substance  does  not  constitute,  as  has  been  here- 
tofore imagined,  the  membranes  of  the  tissue  of  the  perisperm  of  the  wheat ;  but  is  inclosed 
in  cells  of  that  tissue  under  the  epidermic  coats,  even  to  the  centre  of  the  grain.  In  this 
respect  the  gluten  lies  in  a  situation  analogous  to  that  of  the  starch,  and  of  most  of  the  im- 
mediate principles  of  the  vegetables.  The  other  immediate  principles  which  play  a  part  in 
panification  are  particularly  the  starch  and  the  sugar  ;  and  they  all  operate  as  follows : — 

"The  diffusion  of  the  flour  through  the  y<atcr  hydrates  the  starch,  and  dissolves  the 
sugar,  the  albumen,  and  some  other  soluble  matters.  The  kneading  of  the  dough,  by  com- 
pleting these  reactions  through  a  more  intimate  union,  favors  also  the  fermentation  of  the 
sugar,  by  bringing  its  particles  into  close  contact  with  those  of  the  leaven  or  yeast ;  and  the 
drawing  out  and  laminating  the  dough  softens  and  stratifies  it,  introducing  at  the  same  time 
oxygen  to  aid  the  fermentation.  The  dough,  when  distributed  and  formed  into  loaves,  is 
kept  some  time  in  a  gentle  warmth,  in  the  folds  of  the  cloth,  pans,  &c.,  a  circumstance  pro- 
pitious to  the  development  of  their  volume  by  fermentation.  The  dimensions  of  all  the 
lumps  of  dough  now  gradually  enlarge,  from  the  disengagement  of  carbonic  acid  in  the  de- 
composition of  the  sugar,  which  gas  is  imprisoned  by  the  glutinous  paste.  "Were  these  phe- 
nomena to  continue  too  long,  the  dough  would  become  too  vesicular ;  they  must,  therefore, 
be  stopped  at  the  proper  point  of  sponginess,  by  placing  the  loaf  lumps  in  the  oven. 
Though  this  causes  a  sudden  expansion  of  the  enclosed  gaseous  globules,  it  puts  an  end  to 
the  fermentation,  and  to  their  growth  ;  as  also  evaporates  a  portion  of  the  water. 

"  The  fermentation  of  a  small  dose  of  sugar  is,  therefore,  essential  to  true  bread-making  ; 
but  the  quantity  actually  fermented  is  so  small  as  to  be  almost  inappreciable.  It  seems 
probable  that  in  well-made  dough  the  whole  carbonic  acid  that  is  generated  remains  in  it, 
amounting  to  one-half  the  volume  of  the  loaf  itself  at  its  baking  temperature,  or  212"  F.  It 
thence  results  that  less  than  one-hundredth  part  of  the  weight  of  the  flour  is  all  the  sugar 
requisite  to  produce  well-raised  bread. 

"  Although  the  rising  of  the  dough  is  determined  by  the  carbonic  acid  resulting  from 
the  decomposition  of  the  sugar,  produced  by  the  reaction  of  the  gluten  on  hydrated  or  moist 
flour,  considering  that  the  quantity  of  sugar  necessary  to  produce  fermentation  does  not 
amount,  probably,  to  more  than  one-hundredth  part  of  the  weight  of  the  flour  employed, 
and  perhaps  to  even  considerably  less  than  that, — the  saving  and  economy  which  is  said  to 
accrue  to  the  consumer  from  the  use  of  unfermented  bread  (which  is  bread  in  which  the  ac- 
tion of  yeast  is  replaced  by  an  artificial  evolution  of  carbonic  acid,  by  decomposing  bicar- 
bonate of  soda  with  nuiriatic  acid,  as  we  said  before)  is  therefore  much  below  what  it  has 
been  estimated  (25  per  cent.  !)  by  some  writers  ;  and  it  is  certainly  very  far  from  compen- 
sating for  the  various  and  serious  drawbacks  which  are  peculiar  to  that  kind  of  bread,  one 
of  which — and  it  is  not  tlie  least — is  its  indigestibility,  notwithstanding  all  that  may  have 
been  said  to  the  contrary. 

"  In  a  pamphlet  entitled,  '  Instructions  for  making  Unfermented  Bread,  by  a  Physician,' 
published  in  I84tj,  the  formula  recommended  for  bread  made  of  wheat  meal  is  as  follows : 
Wheat  meal     -         ...         3  lbs.  avoirdupois. 
Bicarbonate  of  soda         -         -         4J-  drachms  troy. 
Hydrochloric  acid    -         -         -         5  fluid  drachms  and  25  minims,  or  drops. 

Water 30  fluid  ounces. 

Salt f  of  an  ounce  troy. 

"  Bread  made  in  this  manner,"  says  the  author,  "  contains  nothing  but  flour,  common 
salt,  and  water.  It  has  an  agreeable,  natural  taste,  keeps  much  longer  than  common  bread, 
is  im(ch  more  digestible,  and  much  less  disposed  to  turn  acid,"  &c. 

Liebig,  in  his  "  Letters  on  Chemistry,"  very  judiciously  remarks,  "  that  the  intimate 
mixture  of  the  saliva  with  the  bread,  whilst  masticatmg  it,  is  a  condition  which  is  favorable 
to  the  rapid  digestion  of  the  starch ;  wherefore  the  porous  state  of  the  flour  in  fermented 
bread  accelerates  its  digestion." 

Now,  it  is  a  fact,  which  can  readily  be  ascertained  by  any  one,  that  unfermented  bread 


BEE  AD.  183 

is  permeated  by  fluids  with  difficulty.  It  will  not  absorb  water,  hence  its  heavy  and  clammy 
feel ;  nor  saliva,  hence  its  indigestibleness  ;  nor  milk,  nor  butter.  Unfermented  bread  will 
neither  make  soup,  nor  toast,  nor  poultice.  When  a  slice  of  ordinary  bread  is  held  before 
a  bright  fire,  a  portion  of  the  moisture  of  the  bread,  as  the  latter  becomes  scorched,  is  con- 
verted into  steam,  which  penetrates  the  interior  of  the  mass,  and  imparts  to  it  the  spongi- 
ness  so  well  known  in  a  toast  properly  made  ;  but  if  a  piece  of  unfermented  bread  be  treated 
in  the  same  manner,  the  steam  produced  by  the  moisture,  not  being  able  to  penetrate  the 
unabsorbent  mass,  evaporates,  and  the  result  is  an  uuinviting  slice,  toa.sted,  but  hard  inside 
and  out,  and  into  which  butter  penetrates  about  to  the  same  extent  as  it  would  a  wooden 
slab  of  the  same  dimensions. 

"  Fermentation,"  says  Liebig,  "  is  not  only  the  best  and  simplest,  but  likewise  the  most 
economical  way  of  imparting  porosity  to  bread  ;  and  besides,  iheinisti^,  generally  speaking, 
should  never  recommend  the  use  of  chemicals  for  culinary  preparatio7is^  for  chemicals  are 
seldom  met  with  in  commerce  in  a  state  of  purity.  Tims,  for  example,  the  muriatic  acid 
which  it  has  been  proposed  to  mix  with  carbonate  of  soda  in  bread  is  always  very  impure, 
and  very  often  contains  arsenic.  Chemists  never  employ  such  an  acid  in  operations  which 
are  certainly  less  important  than  the  one  just  mentioned,  without  having  first  purified  it." 

In  order  to  remove  this  ground  of  objection,  tartaric  acid  has  been  recommended  instead 
of  muriatic  acid  for  the  purpose  of  decomposing  the  carbonate  of  soda  ;  but  in  that  way  an- 
other unsafe  compound  is  introduced,  since  the  result  of  the  reaction  is  tartrate  of  soda,  a 
diuretic  aperient,  and  consequently  very  objectionable  salt,  for  it  is  impossible  to  say  what 
mischief  the  continuous  ingestion  of  such  a  substance  may  eventually  produce  ;  and  what- 
ever may  be  the  divergence  of  opinion, — if  there  be  such  a  divergence, — as  to  whether  or 
not  the  constant  use  of  an  aperient,  however  mild,  may  be  detrimental  to  health,  it  surely 
must  be  admitted  that,  at  any  rate,  it  is  better  to  eschew  such,  to  say  the  least  of  it,  suspi- 
cious materials  ;  and  that,  at  any  rate,  if  deprecating  their  use  be  an  error,  it  is  an  error  on 
the  safe  side  ; — after  all,  a  bakehouse  is  not  a  chemical  lalioratory. 

Before  leaving  this  question  of  unfermented  bread,  we  must  not  omit  to  speak  of  a  re- 
markable process  invented  by  Dr.  Dauglish,  and  which  has  lately  excited  some  attention. 
Without  discussing  the  value  of  the  idea  which  is  said  to  have  led  Dr.  Dauglish  to  invent 
the  process  in  question,  we  shall  simply  describe  Dr.  Dauglish's  method  of  making  bread, 
and  give  his  own  version  of  its  benefits  : — 

"  Taking  advantage  of  the  well-known  capacity  of  water  for  absorbing  carbonic  acid, 
whatever  its  density,  in  quantities  equal  to  its  own  bulk,  I  first  prepare  the  water  which  is 
to  be  used  in  forming  the  dough,  by  placing  it  in  a  strong  vessel  capable  of  bearing  a  high 
pressure,  and  forcing  carbonic  acid  into  it  to  the  extent  of  say  ten  or  twelve  atmospheres," 
(about  150  to  180  lbs.  per  square  inch  ;)  "  this  the  water  absorbs  without  any  appreciable 
increase  in  its  Uulk.  The  water  so  prepared  will  of  course  retain  the  carbonic  acid  in  solu- 
tion so  long  as  it  is  retained  in  a  close  vessel  under  the  same  pressure.  I  therefore  place 
the  four  and  salt,  of  which  the  dough  is  to  be  formtd,  also  in  a  close  vessel  capable  of  bear- 
ing a  high  pressure.  Within  this  vessel,  which  is  of  a  spheroidal  form,  a  simply-constructed 
kneading  apparatus  is  fitted,  worked  from  without  through  a  closely-packed  stuffing  box. 
Into  this  vessel  I  force  an  equal  pressure  to  that  which  is  maintained  in  the  aerated  water- 
vessel  ;  and  then,  by  means  of  a  pipe  connecting  the  two  vessels,  I  draw  the  water  into  the 
flour,  and  set  the  kneading  apparatus  to  work  at  the  same  time.  By  this  arrangement  the 
water  acts  simply  as  limpid  water  among  the  flour,  the  flour  and  water  are  mixed  and 
kneaded  together  into  paste,  and  to  such  an  extent  as  shall  give  it  the  necessary  tenacity. 
After  this  is  accomplished  the  pressure  is  released,  the  gas  escapes  from  the  water,  and  in 
doing  so  raises  the  dough  in  the  most  beautiful  and  expeditious  manner.  It  will  bo  cjuite 
unnecessary  for  me  to  point  out  how  perfect  must  be  the  mcclianical  structure  that  results 
from  this  method  of  raising  dough.  In  the  first  place,  the  mixing  and  kneading  of  the  flour 
and  water  together,  before  any  vesicular  property  is  imparted  to  the  mass,  render  the  most 
complete  incorporation  of  the  flour  and  water  a  matter  of  very  easy  accomplishment ;  and 
this  being  secured,  it  is  evident  that  the  gas  which  forms  the  vesicle,  or  sponge,  when  it  is 
rcleixsed,  must  be  dispersed  through  the  mass  in  a  manner  which  no  other  method — fermen- 
tation not  excepted — could  .accomplish.  But  besides  the  advantages  of  kneading  the  dough 
before,  the  vesicle  is  formed,  in  the  manner  .ibove  mentioned,  there  is  another,  and  perhaps 
a  more  important  one,  from  what  it  is  likely  to  effect  l)y  giving  scope  to  the  introduction 
of  new  materials  into  bread-making, — and  that  is,  I  find  that  powerful  machine-kne.ading, 
continued  for  several  minutes,  has  tiie  effect  of  imparting  to  the  dough  tenacity  or  tougli- 
ivess.  In  Messrs.  Carr  and  Co.'s  machine,  at  Carlisle,  we  have  kneaded  some  wlieaten  dougli 
for  half  an  hour,  and  the  result  has  ))een  that  the  dough  has  been  so  toiigli  that  it  resembled 
birdlime,  and  it  was  with  difficulty  pulled  to  pieces  with  tlie  linnd.  (Hher  materials,  such 
as  rye,  barley,  &c.,  are  affected  in  the  same  manner.  So  that  by  thus  kneading,  I  am  able 
to  imp.art  to  dough  made  from  materials  which  otherwise  would  not  make  light  bread,  from 
their  wanting  that  quality  in  their  gluten  which  is  capable  of  holding  or  retaiiung,  the  same 
degree  of  lightness  which  no  other  method  is  capable  of  effecting.     And  I  am  sanguine  of 


184  BEE  AD. 

being  able  to  make  from  rye,  barley,  oatmeal,  and  other  wholesome  and  nutritious  sub- 
stances, bread  as  light  and  sweet  as  the  finest  wheaten  bread.  One  reason  why  my  process 
makes  a  bread  so  different  from  all  other  processes  where  fermentation  is  not  followed,  is, 
that  I  am  enabled  to  knead  the  bread  to  any  extent  without  spoiling  its  vesicular  property  ; 
whilst  all  other  unfermented  breads  are  merely  mixed,  not  kneaded.  The  property  thus 
imparted  to  my  bread  by  kneading,  renders  it  less  dependent  on  being  placed  immediately 
in  the  oven.  It  certaintly  cannot  gain  by  being  allowed  to  stand  after  the  dough  is  formed, 
but  it  bears  well  the  necessary  standing  and  waiting  required  for  preparing  the  loaves  for 
biUiing. 

"  There  is  one  point  which  requires  care  in  my  process,  and  that  is,  the  baking, — as  the 
dough  is  excessively  cold ;  first,  because  cold  water  is  used  in  the  process ;  and  next,  be- 
cause of  its  sudden  expansion  on  rising.  It  is  thus  placed  in  the  oven  some  40°  Fahr.  in 
temperature  lower  than  the  ordinary  fermented  bread.  This,,  together  with  its  slow  spring- 
ing until  it  reaches  the  boiling  point,  renders  it  essential  that  the  top  crust  shall  not  be 
formed  until  the  very  last  moment.  Thus,  I  have  been  obliged  to  have  ovens  constructed 
which  are  heated  through  the  bottom,  and  are  furnished  with  the  means  of  regulating  the 
heat  of  the  top,  so  that  the  bread  is  cooked  through  the  bottom ;  and,  just  at  the  last,  the 
top  heat  is  put  on  and  the  top  crust  formed. 

"  With  regard  to  the  gain  effected  by  saving  the  loss  by  fermentation,  I  may  state  what 
must  be  evident,  that  the  weight  of  the  dough  is  always  exactly  the  sum  of  the  weight  of 
flour,  water,  and  salt  put  into  the  mixing  vessel ;  and  that,  in  all  our  experiments  at  Carlisle, 
we  invariably  made  118  loaves  from  the  same  weight  of  flour  which  by  fermentation  made 
only  105  and  106.  Our  advantage  in  gain  over  fermentation  can  only  be  equal  to  the  Zo.ss 
by  fermentation.  As  there  has  been  considerable  difference  of  opinion  among  men  of 
science  with  respect  to  the  amount  of  this  loss, — some  stating  it  to  be  as  high  as  17+  per 
cent,  and  others  so  low  as  1  per  cent., — I  will  here  say  a  few  words  on  the  subject.  Those 
who  have  stated  the  loss  to  be  as  high  as  17+  per  cent,  have,  in  support  of  their  position, 
pointed  to  the  extra  yield  from  the  same  flour  of  bread  when  made  by  non-fermentation, 
compared  with  that  made  by  fermentation.  "Whilst  those  who  have  opposed  this  assertion, 
and  stated  the  loss  to  be  but  1  per  cent,  or  little  more,  have  declared  the  gain  in  weight  to 
be  simply  a  gain  of  extra  water,  and  have  based  their  calculations  of  loss  on  the  destruction 
of  material  caused  by  the  generation  of  the  necessary  quantity  of  carbonic  acid  to  render  the 
bread  light.  Starting  then  with  the  assumption  that  light  bread  contains  in  bulk  half  solid 
matter  and  half  aeriform,  they  have  calculated  that  this  quantity  of  aeriform  matter  is  ob- 
tained by  a  destruction  of  but  one  per  cent,  of  solid  material,  in  this  calculation  the  loss 
of  carbonic  acid,  by  its  escape  through  the  mass  of  dough  during  the  process  of  fermenta- 
tion and  manufacture,  does  not  appear  to  have  been  taken  into  account.  All  who  have 
been  in  any  way  practically  connected  with  bakeries,  well  know  how  large'this  lose  is,  and 
how  important  it  is  that  it  should  be  taken  into  account,  that  our  calculations  may  be 
correct. 

"  One  of  the  strongest  proofs  that  the  escape  of  gas  through  ordinary  soft  bread  dough 
is  very  large,  arises  from  the  fact  that  when  biscuit  dough,  in  which  there  is  a  mixture  of 
fatty  matter,  is  prepared  by  my  process,  about  half  the  quantity  of  gas  only  is  needed  to 
obtain  an  equal  amount  of  lightness  with  dough  that  is  made  of  flour  and  water  only,  the 
fatty  matter  acting  to  prevent  the  escape  of  gas  from  the  dough.  Other  matters  will  ope- 
rate in  a  similar  manner — boiled  flour,  for  instance,  added  in  small  quantities.  But  the  as- 
sinnption  tliat  light  bread  is  only  half  aeriform  matter  is  altogether  erroneous.  Never  before 
has  there  been  so  complete  a  method  of  testing  what  proportion  the  aeriform  bears  to  the 
solid  in  light  bread  as  that  wliich  my  process  affords.  Tlie  mixing  vessel  at  Messrs.  Carr  and 
Co.'s  works,  Carlisle,  has  an  internal  capacity  of  10  bushels.  "When  3+  bushels  of  flour  are 
put  into  this  vessel,  and  formed  into  spongy  bread  dough,  by  my  process,  it  is  quite  full. 
And  when  flour  is  mixed  with  water  into  paste,  the  paste  measures  rather  less  than  half  the 
bulk  of  the  original  dry  flour.  This  will  therefore  represent  about  If  liushels  of  solid  mat- 
ter expanded  into  10  bushels  of  spongy  dough,  showing  in  the  dovgh  nearly  5  farts,  airi- 
form  to  1  solid  ;  and  in  all  instances,  if  the  baking  of  this  dough  has  not  been  accomplished 
so  as  to  secure  the  loaves  to  '  spring  '  to  at  least  double  their  size  in  the  oven,  they  liave 
always  come  out  heavy  bread  when  compared  with  the  ordinary  fermented  loaves.  This 
gives  the  relative  proportion  of  aeriform  to  solid  in  light  bread  at  least  as  10  to  1,  and  at 
once  raises  the  loss  by  fermentation  from  1  to  10  per  cent.,  without  taking  into  account  the 
loss  of  gas  by  its  passage  through  the  mass  of  dough. 

"  Of  the  quality  and  properties  of  the  bread  manufactured  by  my  process,  there  will 
shortly  be  ample  means  of  judging.  I  may  be  allowed,  however,  here  to  state,  what  will  be 
evident  to  all,  that  the  absence  of  every  thing  but  flour,  water,  and  salt,  must  render  it 
absolutely  pure  ; — that  its  sweetness  cannot  lie  e(|ualled  except  by  bread  to  which  sweet 
materials  arc  superadded  ; — that,  unlike  all  other  unfermented  bread,  it  makes  excellent 
toast ;  and,  on  account  of  its  high  absorbent  power,  it  makes  the  most  delicious  sop  pud- 
dings, &c.,  and  also  excellent  poultice.     Sop  pudding  and  poultice  made  from  this  biead, 


BREAD. 


185 


however,  differ  somewhat  from  those  made  from  fermented  bread,  in  being  somewhat  richer 
or  more  glutinous.  This  arises  from  the  fact  of  the  gluten  not  having  been  changed,  or 
rendered  soluble,  in  the  manner  caused  by  fermentation  ;  but  that  this  is  a  good  quality 
rather  than  a  bad  one,  is  evident  from  the  fact,  that  the  richer  and  purer  i'ennented  bread  is, 
the  more  glutinous  are  the  sop,  &c.,  made  from  it ;  and  the  poorer  and  more  adulterated 
with  alum  it  is,  the  freer  the  sop,  kc,  are  of  this  ciuality." 

Such  then,  is  Dr.  Dauglish's  plan,  and  it  is  impossible  to  deny  that  it  possesses  great 
ingenuity. 

From  the  fact  that,  in  all  his  experiments  at  Carlisle,  Dr.  Dauglish  invariably  made  118 
loaves  from  the  same  weight  of  flour  which,  by  fermentation,  made  only  lii5  or  100,  to 
argue  that  the  ffain  over  fermentation  can  only  be  equal  to  the  loss  by  fermentation,  is  to 
draw  a  somewhat  hasty  conclusion ;  for  the  gain  may  be,  and  is  probably  due,  not  to  the 
preservation  in  the  bread  of  wliat  is  generally  lost  by  fermentation,  but  simply  to  a  reten- 
tion of  water. 

It  is  of  course  certain  that  the  production  of  the  porosity  required  in  bread  produced  by 
the  carbonic  acid  and  alcohol  evolved  by  fermentation,  entails  the  loss  of  a  portion  of  the 
valuable  constituents  of  the  flour,  but  the  amount  of  that  loss  should  not  be  estimated,  I 
think,  from  the  proportions  which  the  auriform  bear  to  the  solid  matter  of  the  loaf  after  it 
is  baked. 

In  effect,  the  fermentation  induced  in  bread  differs  from  that  produced  at  the  distillery, 
inasmuch  as,  instead  of  the  fermenting  material  being  sheltered  from  the  air  by  an  atmos- 
phere of  carbonic  acid,  the  dough  is  on  the  contrary  thoroughly  permeated  by,  and  retains  a 
considerable  quantity  of  atmospheric  air  introduced  into  it  by  the  kneading  process,  and 
owing  to  the  presence  of  which,  in  fact,  the  acetous  fermentation  is  carried  on  to  a  certain 
extent,  within  the  dough,  simultaneously  with  the  alcoholic  fermentations,  so  that  even  the 
10  parts  of  aeriform  matter  to  1  of  solid  matter  in  a  quartern  loaf,  are  not  altogether  car- 
bonic acid  resulting  from  the  fermentation,  but  are  carbonic  acid  from  that  source  mixed 
with  the  atmospheric  air  with  which  the  dough  is  permeated.  On  the  other  band,  the  aeri- 
form matter  thus  imprisoned  in  the  dough,  expands  to  at  least  twice  its  volume  when  ex- 
posed to  the  temperature  of  the  oven,  and  accordingly  the  bread  after  baking  becomes  as 
bulky  again  as  the  dough  from  which  it  was  made,  and  this  doubling  of  the  volume  being 
due  to  the  expansion  of  the  gases,  and  not  to  the  fermentation,  bears  no  proportion  what- 
ever to  the  amount  of  the  sugar  of  the  flour  employed  in  the  production  of  the  alcohol  and 
carbonic  acid  evolved.  Moreover,  as  a  quartern  loaf,  for  example,  measures  about  9  inches 
by  6-5  inches  by  5  inches,  making  a  total  of  about  292  cubic  inches,  if  we  take  nine-tenths 
of  that  to  be  aeriform  matter,  we  have  2i)2-8  inches  as  the  aeriform  cubic  contents  of  the 
quartern  loaf. 

It  is  ascertained  beyond  doubt  by  numerous  experiments,  that  genuine,  properly  manu- 
factured new  bread  contains,  on  an  average,  42'5  per  cent,  of  water,  and  S^'S  of  flour,  and 
consequently  a  quartern  loaf  weighing  really  four  pounds,  would  consist  of  11,900  grains 
of  water  and  16,000  grains  of  solid  matter,  422-5  grains  of  which  are  salt  and  inorganic 
matter;  the  rest,  15677'5  grains,  being  starch  and  gluten.  Now  a  quartern  loaf  measuring 
about  9  X  6'5  X  5  inches,  gives  a  total  of  292  cubic  inches.  Assuming,  with  Dr.  Dauglish, 
nine-tenths  of  that  to  be  aeriform  matter,  we  have  262-8  inches  as  the  aeriform  cubic  con- 
tents of  a  quartern  loaf,  but  as  the  gases  expanded  in  the  dough  to  double  their  volume 
duj'ing  its  being  baked  into  a  loaf,  we  must  divide  by  2  the  202-8  inches  above  alluded  to, 
which  gives  131--i  as  the  number  of  cubic  inches  of  aeriform  matter  contained  in  the  dough 
before  it  went  into  the  oven.  Again,  assuming  with  Dr.  Dauglish  that  these  131-4  cul»ic 
inches  consist  altogether  of  carbonic  acid  resulting  from  the  fermentation  of  the  flour,  they 
would  represent  in  weight  only  02  grains  of  that  gas,  and  as  1  equivalent  =  198  of  sugar 
produces  4  equivalents  =  88  of  carbonic  acid,  it  follows  that,  at  most,  about  140  grains  of 
sugar  or  solid  matter  out  of  the  15077-5  of  flour  in  the  quartern  loaf  would  have  disappeared, 
wliich  loss  is  less  than  1  per  cent.,  from  which,  however,  it  is  necessary  to  make  a  cousidi'r- 
able  reduction,  since  a  large  quantity  of  air  is  mixed  with  that  carbonic  acid,  and  expanded 
with  it  in  the  oven.  Unless,  therefore,  it  can  be  satisfactorily  proved  that  the  unfcrincnted 
bread  manufactured  by  Dr.  Dauglish's  process  is  more  nutritious,  weight  for  weight,  or  more 
digestible,  or  possesses  qualities  which  fermented  bread  has  not,  or  is  sold  at  a  reduced  price 
proportionate  to  the  quantity  of  water  thus  locked  up  and  passed  off  for  bread,  the  benefits 
and  advantages  will  be  all  on  the  manufacturer's  side,  but  the  purchasers  of  the  unfermentetl 
bread  will  make  but  a  poor  bargain  of  it. 

Of  all  the  operations  connected  with  the  manufacture  of  bread,  the  most  laborious,  and 
that  which  calls  most  loudly  for  reform,  is  that  of  kneading.  The  process  is  usually  carried 
on  in  some  dark  corner  of  a  cellar,  where  th<!  temperature  is  .seldom  less  than  00'  F.,  and 
frequently  more  ;  by  a  man,  stripped  naked  down  to  the  waist,  and  painfully  engaged  in 
extricating  his  fingers  from  a  gluey  mass  into  which  he  furiously  plunges  alternately  his 
clenched  fists,  heavily  breathing  as  he,  struggling,  repeatedly  lifts  up  the  bulky  and  tena- 


180 


BKEAD. 


cious  mass  in  his  powerful  arms,  and  with  effort  flings  it  down  again  with  a  groan  fetched 
from  the  innermost  recesses  of  liis  chest,  and  which  almost  sounds  like  an  imprecation. 

Wc  know,  on  very  good  and  unexceptionable  authority,  that  a  certain  large  bakery  on 
the  borders  of  a  canal,  actually  pumped  the  water  necessary  for  making  the  dough  directly 
and  at  once  from  the  canal,  and  this  I'rom  a  point  exactly  contiguous  to  the  dischargings  of 
the  cesspool  of  that  bakery  !  And  let  us  not  imagine  that  this  is  a  solitary  instance  of  hor- 
riljle  filth.  The  following  memoranda,  recorded  by  Dr.  "Wm.  A.  Guy,  in  his  admirable  lec- 
ture on  "  The  Evils  of  Night-work  and  Long  Hours  of  Labor,"  delivered  on  Thursday,  July 
G,  1848,  at  the  Mechanics'  Institution,  Southampton  Buildings,  will  serve  to  illustrate  the 
condition  of  the  bakehouses  : — 

1.  Underground,  two  ovens,  no  daylight,  no  ventilation,  very  hot  and  sulphurous. 

2.  Underground,  no  daylight,  two  ovens,  very  hot  and  sulphurous,  low  ceiling,  no  ven- 

tilation but  what  comes  from  the  doors.     Very  large  business. 

3.  Underground,  no  daylight,  often  Hooded,  very  bad  smells,  overrun,  with  rats,  no  ven- 

tilation. 

After  mentioning  several  other  establishments  in  the  same,  or  even  in  a  worse  condition, 
than  those  just  enumerated.  Dr.  Guy  adds: — 

"  The  statements  comprised  in  the  foregoing  memoranda  are  in  conformity  with  my  own 
observations.  Many  of  the  basements  in  which  the  business  of  baking  is  carried  on  are  cer- 
tainly in  a  state  to  require  the  assistance  of  the  Commissioners  of  Sewers,  and  to  invite  the 
attention  of  the  promoters  of  sanitary  reform." 

If  we  reflect  that  bread,  like  all  porous  substances,  readily  absorbs  the  air  that  surrounds 
it,  and  that,  even  under  the  best  conditions,  it  should  never,  on  that  account,  be  kept  in 
confined  places,  what  must  bo  the  state  of  the  bread  manufactured  in  such  a  villanous  man- 
ner, and  with  a  slovenliness  greater  than  it  is  possible  for  our  imagination  to  conceive  ? 
What  can  prove  better  the  necessity  of  Government  supervision  than  such  a  fact  ?  The 
heart  sickens  at  the  revolting  thought,  but,  after  all,  there  is  really  but  little  difference  be- 
tween the  particular  case  of  the  bakery  on  the  border  of  a  canal  above  alluded  to,  and  the 
mode  of  kneading  generally  pursued,  and  to  which  we  daily  submit. 

In  the  sitting  of  tlie  Institute  of  France,  on  the  23d  of  January,  1850,  the  late  M.  Arago 
presented  and  recommended  to  the  Academic  the  kneading  and  baking  apparatus  of  M. 
Holland,  then  a  humble  baker  of  the  12th  Arrondissement,  which,  it  would  appear,  fulfiJs 
all  the  conditions  of  perfect  kneading  and  baking. 

"  The  kneading  machine  {petrin  micaiiiqiu:)  of  M.  Rolland,"  says  Arago,  "is  extremely 
simple,  and  can  be  easily  worked,  when  under  a  full  charge,  by  a  young  man  from  15  to  20 
years  old  :  the  necessity  for  horse  labor  or  steam  power  may  thus  be  obviated.  The  machine 
(figs.  71  to  74)  consists  of  a  horizontal  axis  traversing  a  trough  containing  all  the  dough 
requisite  for  one  baking  batch,  and  upon  which  axis  a  system  of  curvilinear  blades,  alter- 
nately long  and  short,  are  placed  in  such  a  manner  that,  while  revolving,  they  describe  two 
quarters  of  cylindrical  surfaces  with  contrary  curves,  so  that  the  convexity  of  one  of  these 
surfaces,  and  the  concavity  of  the  other,  is  turned  towards  the  bottom  of  the  trough.  The 
axis  has  a  fly-wheel,  and  is  set  in  motion  by  two  small  cog-wheels  connected  with  the  han- 
dle, as  represented  in  the  following  figures  : — 


71 


c;;; 


liiliy 


BREAD. 


187 


73 


74 


■I 


Tlie  action  oF  the  kneading  machine  is  both  easy  and  efficacious.  In  20,  and,  if  neces- 
sary, in  15,  or  even  10  minutes,  a  sack  of  flour  may  be  converted  into  a  perfectly  homoge- 
neous and  aerated  dough,  without  either  lumps  or  clods,  and  altogether  superior  to  any 
dough  that  could  be  obtained  by  manual  kneading.  The  time  required  in  kneading  varies 
according  to  the  greater  or  less  density  of  dough  required  ;  and  the  quantity  of  dough  manu- 
factured in  that  space  of  time  varies,  of  course,  also  with  the  dimensions  of  the  kneading- 
trough  ;  for  instance,  in  the  trough  provided  with  16  blades,  one  sack  and  a  half  of  flour 
can  be  kneaded  at  once ;  in  that  of  14  blades,  one  sack,  and  in  that  of  12  blades,  two-thirds 
of  a  sack. 

M.  Rolland  gives  the  following  instructions  for  the  use  of  the  machine,  in  order  to  im- 
part to  the  dough  the  qualities  produced  by  the  operations  known  in  France  under  the  names 
oi  frasage,  contrefraxage,  and  sonffiage,  which  we  shall  presently  describe,  and  to  which  the 
bread  manufactured  in  that  country  mainly  owes,  in  the  words  of  Dr.  Ure,  "  a  flavor,  color, 
and  texture,  never  yet  equalled  in  London." 

The  necessary  quantity  of  leaven  or  yea^t  is  fi)-st  diluted  with  the  proper  quantity  of 
water,  as  described  before ;  and  in  order  to  effect  the  mixture,  the  crank  should  be  made  to 
perform  50  revolutions  alternately  from  right  to  left. — Frasage  is  the  first  mixture  of  the 
flour  with  the  water.  Tiie  flour  is  simply  poured  into  the  kneading-trough,  or,  better  still, 
when  convenience  permits  it,  it  is  let  down  from  a  room  above  through  a  linen  hose,  which 
may  be  shut  by  folding  it  up  at  the  extremity. 

Three-fourths  only  of  the  flour  should  at  first  be  put  into  the  trough  ;  the  first  revolu- 
tions of  the  kneader  should  be  rather  rapid,  but  during  the  remainder  of  the  operation  the 
turning  should  be  at  the  rate  of  about  two  or  three  revolutions  a  minute,  according  to  the 
density  of  the  dough  to  be  prepared.  The  dough  thereby  having  time  to  be  well  drawn  out 
between  the  blades,  and  to  drop  to  the  bottom  of  the  trough.  From  24  to  36  revolutions 
of  the  crank  will  generally  be  sufficient ;  but  in  order  to  obtain  the  dough  in  the  condition 
which  the  frasage  would  give  it  in  the  usual  way,  it  will  be  necessary  to  make  about  250 
revolutions  of  the  crank  alternately  from  right  to  left,  about  the  same  number  of  turns. 

Conlreframge  is  the  completion  of  the  process  of  mixing  ;  and,  in  order  to  perform  that 
operation,  the  last  fourth  part  of  the  flour  must  now  be  added,  the  crank  turned  150  revolu- 
utions,  to  wit :  75  turns  rather  slowly,  alternately  from  right  to  left,  and  the  remainder  at 
the  rate  of  speed  above  mentioned. 

The  operation  of  soufflagc  consists  in  introducing  and  retaining  air  in  the  paste.  To 
effijct  this,  the  kneader  should  be  made  to  perform,  during  nearly  the  whole  time  occupied 
in  the  operation,  an  almost  continual  motion  backwards  and  forwards,  by  which  means  the 
(lough  is  shifted  from  place  to  place  ;  five  revolutions  being  made  to  the  right,  and  five  to 
the  left,  alternately,  taking  care  to  accelerate  the  speed  a  little  at  the  moment  of  reversing 
the  direction  of  the  revolving  blades. 

All  these  operations  are  accomplished  in  twenty  or  twenty-five  minutes. 

Of  course,  the  reader  should  not  imagine  that  these  numbers  must  be  strictly  followed  ; 
they  are  giv(;n  merely  as  a  guide  indicative  of  the  vwdus  opcrtvuli. 

Tlie  kneading  being  completed,  the  dough  is  left  to  rest  for  some  time,  and  then  divided 
into  lumps,  of  a  proper  weight,  for  each  loaf.  The  workman  takes  one  of  these  lumps  in 
each  hand,  rolls  them  out,  dusts  tlicm  over  with  a  little  flour,  and  puts  each  of  them  sepa- 
rate in  its  panneton ;  he  proceeds  with  the  rest  of  the  dough  in  the  same  maimer,  and 


188 


BREAD. 


leaves  all  the  lumps  to  swell,  which,  if  the  flour  have  been  of  good  quality,  will  take  place 
at  a  uniform  rate.  They  are  then  fit  for  baking,  which  operation  will  be  described  presently. 

The  Hot-water  Oven  Biscuit-baking  Company  possesses  also  a  good  machine  with  -which 
1  cwt.  of  biscuit  dough,  or  2  cwts.  of  bread  dough,  can  be  perfectly  kneaded  in  10  minutes. 
The-  machine  is  an  American  invention,  and  of  extraordinary  simplicity,  for  it  is  in  reality 
nothing  more  than  a  large  corkscrew,  working  in  a  cylinder,  by  means  of  which  the  dough  is 
triturated,  squeezed,  pressed,  torn,  hacked,  and  finally  agglomerated  as  it  is  pushed  along. 
The  dough,  as  it  issues  from  that  machine,  can  at  once  be  shaped  into  loaves  of  suitable  size 
and  dimensions.  A  machine  capable  of  doing  the  amount  of  work  alluded  to  does  not  come 
to  more  than  from  £6  to  £7  ;  the  other  forms  of  kneading  machines  are  likewise  inexpen- 
sive, so  that,  in  addition  to  the  economy  of  time  which  they  realize,  there  does  not  seem  to 
be  any  excuse  for  retaining  the  abomination  of  manual  kneading. 

Among  superior  and  very  desirable  apparatus  for  bread-making,  there  are  at  any  rate 
three  which  fulfil  the  desiderata  above  alluded  to,  in  the  most  complete  and  economical 
manner.  One  of  them  is  M.  Mouchot's  aerothermal  bakery  ;  the  second  is  A.  M.  Perkins' 
hot-water  oven ;  the  third  is  RoUand's  hot-air  oven,  with  revolving  floors  :  all  three  are  ex- 
cellent. 

Perkins'  hot-water  oven  is  an  adaptation  of  that  distinguished  engineers'  stove,  which, 
as  is  well  known,  is  a  mode  of  heating  by  means  of  pipes  full  of  water,  and  hermetically 
closed  ;  but  with  a  sufficient  space  for  the  expansion  of  the  water  in  the  pipes.  As  a  means 
of  warming  buildings,  the  invention  has  already  produced  the  very  beneficial  effects  which 
have  gained  for  it  an  extensive  patronage.  There  is  no  doubt  but  that  this  novel  applica- 
tion entitles  the  inventor  to  the  warmest  thanks  of  the  public.  The  following  figure  (75) 
represents  one  of  these  ovens,  a,  stove  ;  b,  coil  of  iron  pipe  placed  in  the  stove ;  c  c, 
flowpipe ;  d,  expansive  tube ;  e,  oven  charged  with  loaves,  and  surrounded  with  the  hot- 
water  pipes ;  F,  return  hot-water  pipe ;  g,  door  of  the  oven  ;  n,  flue  for  the  escape  of  the 
vapors  in  the  oven  ;  i,  rigid  bar  of  iron  supporting  the  regulating  box  ;  j,  j,  regulating  box 
containing  three  small  levers  ;  k,  nut  adjusted  so  that  if  temperature  of  the  hot-water  pipe 
is  increased  beyond  the  adjusted  point,  its  elongation  causes  the  nut  to  bear  upon  the  levers 
in  the  box,  j,  which  levers,  lifting  the  straight  rod  l,  shut  the  damper  m  of  the  stove ;  n  is 
an  index  indicating  the  temperature  of  the  hot-water  pipes. 

75 


The  oven  is  first  built  in  tlie  ordinary  manner  of  soiuid  lirickwork,  made  very  thick  in 
order  to  retain  the  heat.  Then  the  top  and  bottom  of  the  intci-nal  surfaces  are  lined  with 
wrought-iron  pipes  of  one  inch  external  diameter,  and  five-eighths  of  an  inch  internal  diam- 
eter, and  their  surface  amounts,  in  the  aggregate,  to  the  whole  surface  of  the  oven.  These 
pipes  are  then  connected  to  a  coil  in  a  furnace  outside  the  oven.  The  coil  having  such  a 
ri'lative  proportion  of  surface  to  that  which  is  in  the  oven,  that  the  pipes  may  be  raised  to  a 
temperature  of  SSC  F.,  and  no  more.  This  fixed  and  imiform  temperature  is  maintained 
by  a  self-regulating  adjustment  peculiar  to  this  furnace,  which  works  with  great  precision, 
and  which  cannot  get  out  of  order,  since  it  depends  upon  the  expansion  of  the  upper  as- 
cending pipe  close  to  the  furnace  acting  upon  three  levers  conneetecl  with  the  damper  which 
regulates  the  draught.  The  movable  nut  at  the  bottom  of  that  expanding  pipe  being 
adjusted  to  the  requisite  temperature,  tlwt  precise  temperature  is  uniformly  retained.     The 


BEEAD. 


189 


smallest  fluctuation  in  the  heat  of  the  water  which  circulates  in  the  pipes  instantly  sets  tho 
levers  in  motion,  and  the  expansion  of  one-thirty-sixth  part  of  an  inch  is  sufficient  to  close 
the  damper. 

It  will  be  observed,  that  if  the  pipe  be  heated  to  550"  F.,  the  brickwork  will  soon  attain 
the  same  temperature,  or  nearly  so,  and  accordingly  the  oven  will  thus  possess  double  the 
amount  of  the  heating  surface  of  ordinary  ovens  applicable  to  baking.  The  baking  temper- 
ature of  the  oven  is  from  420'  to  450^  F.,  which  is  ascertained  by  a  thermometer  with 
which  the  oven  is  provided. 

With  respect  to  Rollaud's  oven.  Messieurs  Boussingault,  Payen,  and  Poncelet,  in  their 
report  to  the  Institute  of  France ;  Gaultier  de  Glaubry,  in  a  report  made  in  the  name  of  the 
Committee  of  Chemical  Arts  to  the  Societe  d'Eucouragement ;  and  the  late  M.  Arago, 
represented  that  oven  as  successfully  meeting  all  the  conditions  of  salubrity,  cleanliness,  and 
hv"-iene.  Wood,  coals,  and  ashes,  are  likewise  banished  from  it,  and  neither  smoke  nor 
tlie  heated  air  of  the  furnace  can  find  access  to  it.  As  in  Perkins',  the  furnace  is  placed  at 
a  distance  from  the  mouth  of  the  oven,  but,  instead  of  conveying  the  heat  by  pipes,  as  in 
the  hot-water  oven,  it  is  the  smoke  and  hot  air  of  the  furnace  which,  circulating  through 
fan-shaped  flues,  ramifying  under  the  floor,  and  spreading  over  the  roof  of  the  oven,  impart 
to  it  the  requisite  temperature.  The  floor  of  the  oven,  on  which  the  loaves  are  deposited, 
consists  of  glazed  tiles,  and  it  can  thus  be  kept  perfectly  clean.  The  distinctive  character 
of  M.  Holland's  oven,  however,  is  that  the  glazed  tiles  just  spoken  of  rest  upon  a  revolving 
platform,  which  the  workman  gradually,  or  from  time  to  time,  moves  round  by  means  of  a 
small  handle,  and  without  effort. 

Figures  70  to  85  represent  the  construction  and  appearance  of  M.  Piolland's  oven  on  a 
reduced  scale. 


80. 


Front  elevation. 

Vertical  section   through  the  axis 

of  the  fire-grate. 
Ditto,  ditto. 

Elevation  of  one  of  the  vertical  flues. 
Suspension  of  the  floors. 


81.  Plan  of  the  first  floor. 

82.  Plan  of  the  sole. 

83.  Plan  of  the  second  floor. 

84.  Plan  of  the  fire-grate  and  flues. 

85.  Plan  of  the  portion  under  ground. 


When  the  oven  has  to  be  charged,  the  workman  deposits  the  first  loaves,  by  means  of  a 
short  peel,  upon  tliat  part  of  the  revolving  platform  which  lies  before  the  mouth  of  the  oven, 
and  when  that  portion  is  filled,  he  gives  a  turn  witli  the  handle,  and  proceeds  to  put  the 
loaves  in  the  fresh  space  thus  presented  Ijctbre  him,  and  so  on,  until  the  whole  is  fitted  up. 
The  door  is  then  closed  through  an  opening  covered  with  glass,  and  reserved  in  the  wall  of 
the  oven,  which  is  lighted  up  with  a  jet  of  gas,  or  by  opening  the  door  from  time  to  time, 
the  progress  of  the  baking  may  be  watched  ;  if  it  appears  too  rapid  on  one  point,  or  too 
slow  on  another,  the  journeyman  can,  by  means  of  the  handle,  bring  the  loaves  successively 
to  the  hottest  part  of  tlie  oven,  and  vice  versa,  as  occasion  may  r('(|uire.  The  ovc-n  is  pro- 
vided with  a  thermometer,  and,  in  an  experiment  witnessed,  the  temperature  indicated 
210"  C.  =  410'  F.,  the  baking  of  a  full  charge  was  completed  in  one  hour  and  ton  minutes, 
and  the  loaves  of  the  same  kind  were  so  even  in  point  of  size  and  color  that  they  could  not 
be  distinguished  from  each  other. 

The  top  of  the  oven  is  provided  with  a  pan  for  tlie  jiurpose  of  heating  the  water  neces- 
sary for  the  preparation  of  the  dough,  }>}•  means  of  the  heat  which  in  all  other  plans  (Mou- 
chot's  excepted)  is  lost.     The  workman  should  take  care  to  keep  always  some  water  in  that 


190 


BREAD. 


pan,  for  otherwise  the  leaden  pipe  would  melt  and  occasion  dangerous  leaks.  For  this  and 
other  reasons,  the  safest  plan,  however,  would  be  to  replace  this  leaden  pipe  by  an  iron 
one.     The  said  pan  should  be  frequently  scoured,  for,  if  neglected,  the  water  will  become 

11 


^7 


^v- 


rusty,  and  spoil  the  color  of  the  broad.     Bread-baking  may  be  considered  as  consisting  of 
four  operations — namely,  heating  the  oven,  putting  the  dough  into  the  oven,  baking,  and 


BREAD. 


82 


83 


- -,    84 


191 


192 


BREAD. 


taking  the  loaves  out  of  the  oven.  The  general  directions  given  by  M.  RoUand  for  each  of 
these  operations  are  as  follows  : — 

In  order  to  obtain  a  proper  heat,  and  one  that  may  be  Qasily  managed,  it  is  necessary  to 
charge  the  furnace  moderately  and  often,  and  to  keep  it  in  a  uniform  state. 

When  the  fire  is  kindled,  tlie  door  should  be  kept  perfectly  closed,  in  order  to  compel 
the  current  of  air  necessary  to  the  combustion  to  pass  through  the  grate,  and  thence  through 
the  flues  under  and  the  dome  over  the  oven.  If,  on  the  contrary,  the  furnace  door  were 
left  ajar,  the  cold  air  from  without  would  rapidly  pass  over  the  coals,  without  becoming 

85 


properly  heated,  and,  passing  in  that  condition  into  the  flues,  would  fail  in  raising  it  to  the 
proper  temperature.  In  order  that  the  flame  and  heated- products  of  the  combustion  may 
pass  through  all  the  flues,  it  is,  of  course,  necessary  to  keep  them  clear  by  introducing  into 
them  once  a  month  a  brush  made  of  wire,  or  whalebone,  or  those  which  are  now  generally 
used  for  sweeping  the  tubes  of  marine  tubular  boilers,  and  the  best  of  which  are  those 
patented  and  manufactured  by  Messrs.  Moriarty,  of  Greenwich,  or  How,  of  London.  The 
vertical  flues  which  are  built  in  the  masonry  are  cleared  from  without  or  from  the  pit,  ac- 
cording to  the  nature  of  the  plan  adopted  in  building  the  oven.  These  flues  need  not  be 
cleaned  more  often  than  about  once  in  three  months. 


Sweeping  between  the  floors  should  ])c  performed  about  every  fortnight. 

In  case  of  accident  or  injury  to  the  thermometers,  the  following  directions,  which,  in- 
deed, apply  to  all  ovens,  may  enalile  the  baker  to  judge  of  the  temperature  of  his  oven  : — 
If,  on  throwing  a  few  pinches  of  flour  on  the  tiles  of  the  oven,  it  remains  white  after  the 
lapse  of  a  few  seconds,  the  temperature  is  too  low  ;  if,  on  the  contrary,  the  flour  assumes  a 
deep  brown  color,  the  temperature  is  too  high  ;  if  the  flour  turns  yellowish,  or  looks  slightly 
scorched,  the  temperature  is  right. 

The  baking  in  RoUand's  oven  takes  place  at  a  temperature  varying  from  410°  to  432° 
F.,  according  to  the  nature  and  size  of  the  articles  intended  to  be  baked.  During  the  baking, 
the  revolving  floor  is  turned  every  ten  or  twelve  minutes,  so  that,  the  loaves  not  remaining 
in  the  same  place,  the  baking  becomes  equal  throughout. 


BREAD.  193 

As  to  the  hot-water  oven,  two  cstabhshments-only  have  as  yet  adopted  it  in  England  ; 
one  of  them  is  the  "  Hot- water  Oven  Biscuit-baking  Company,"  on  whose  premises  fancy 
biscuits  only  are  baked  ;  the  second  establishment  is  that  of  a  baker  of  the  name  of  Neville, 
carrying  on  his  business  in  London. '  With  respect  to  M.  Mouchot's  system,  it  is  not  even 
known  in  this  country,  otherwise  than  by  having  been  alluded  to  in  one  or  two  techno- 
logical publications  or  dictionaries. 

The  quantity  of  bread  which  can  be  made  from  a  sack  of  flour  depends  to  a  great  extent 
upon  the  quantity  of  gluten  that  the  flour  of  which  it  is  made  contains,  but  the  wheat  which 
contains  a  large  proportion  of  nitrogenous  matter,  does  not  yield  so  white  a  flour  as  those 
which  are  poorer.  From  a  great  number  of  determinations,  it  is  found  that  the  amount  of 
gluten  contained  in  the  flour  to  make  best  white  bread  ranges  from  10  to  18  per  cent.,  that 
of  the  starch  being  from  63  to  10  per  cent.,  the  ashes  ranging  from  0-5  to  l-'J  per  cent. 

This  day,  (17th  of  March,  185S,)  the  sack  of  genuine  best  household  flour,  weighing  280 
lbs.,  delivered  at  the  bakers'  shop,  costs  42s.,  and  the  number  of  sacks  of  flour  converted 
weekly  into  bread  by  the  London  bakers  is  nearly  30,000,  which  gives  about  12  sacks  of 
flour  per  week  as  the  average  trade  of  each  of  them.  The  average  capital  of  a  baker  doing 
that  amount  of  business  may  be  computed  at  £300,  which,  at  5  per  cent.,  gives  £15  interest ; 
his  rent  may  be  estimated  at  about  £55,  and  the  rates,  taxes,  gas,  and  other  expenses  at 
about  £25,  in  all  £95,  or  very  nearly  £1  16s.  6ld.  per  week,  which  sum,  divided  by  12, 
would  give  3s.  O^d.  per  sack. 

In  the  ordinary  plan  of  bread-making,  London  bakers  reckon  that  1  sack  of  such  a  flour, 
weighing  280  lbs.,  will  make  90  real  4-lb.  loaves  (not  quartern)  of  pure,  genuine  bread, 
although  a  sack  of  such  flour  may  yield  him  94  or  even  95  quartern  (not  4-lb.)  loaves.* 

From  this  account  it  may  be  easily  imagined  that  if  the  baker  could  succeed  in  dispos- 
ing at  once  of  all  the  loaves  of  his  day's  baking  either  by  sale  at  his  shop,  or,  still  better,  by 
delivery  at  his  customers'  residences,  such  a  business  would  indeed  be  a  profitable  one, 
commercially  speaking,  for  on  that  day  he  would  sell  from  28  to  84  lbs.  of  water  at  the 
price  of  bread,  not  to  speak  of  the  deficient  weight ;  but,  on  the  one  hand,  so  many  people 
provokingly  require  to  have  their  loaves  weighed  at  the  shop,  and  are  so  stingily  particular 
about  having  their  short  weight  made  up  ;  and,  on  the  other  hand,  the  loaves,  between  the 
first,  second,  and  third  day,  do  so  obstinately  persist  in  letting  their  water  evaporate,  that 
the  loss  of  weight  thus  sustained  nearly  balances  the  profit  obtained  upon  the  loaves  sold  on 
the  first  day  at  the  shop,  or  to  those  customers  who  have  their  bread  delivered  at  their 
own  door,  to  those  who  the  baker  knows,  from  position  or  avocations,  will  never  take  the 
trouble  to  verify  the  weight  of  his  loaves,  and  who,  he  says,  are  gentlefolks,  and  no  mistake 
about  it. 

As  to  those  bakers  who,  by  underbaking,  or  by  the  use  of  alum,  or  by  the  use  of  both 
alum  and  underbaking,  manage  to  obtain  96,  98,  100,  or  a  still  larger  number  of  loaves 
from  inferior  flour,  or  materials,  their  profit  is  so  reduced  by  the  much  lower  price  at  which 
they  are  compelled  to  sell  their  sophisticated  bread,  that  their  tamperings  avail  them  but 
little  ;  their  emphatically  hard  labor  yields  them  but  a  mere  pittance,  except  their  business 
be  so  extensive  that  the  small  profits  swell  up  into  a  large  sum,  in  which  case  they  only 
jeopardize  their  name  as  fiiir  and  honest  tradesmen. 

Looking  now  at  the  improved  ovens,  of  which  we  have  been  speaking  merely  in  an 
economical  point  of  view,  and  abstractedly  from  all  other  considerations,  the  profits  realized 
by  their  use  appears  to  be  well  worth  the  baker's  attention.  But  as  with  the  improved 
ovens  the  economy  bears  upon  the  wages  and  the  fuel,  the  advantages  are  much  less  consider- 
able in  a  small  concern  than  in  a  large  one.  Thus,  the  economy  which,  upon  12  sacks  of 
flour  per  week,  would  scarcely  exceed  20  shillings  upon  the  whole,  would,  on  the  contrary, 
assume  considerable  proportions  in  establishments  baking  from  50  to  100  sacks  per  week. 
We  give  here  the  following  comparative  statements  of  converting  flour  into  bread  at  the 
rate  of  70  sacks  per  week,  from  documents  which  may  be  fully  reHed  upon.  70  sacks  of 
flour  manufactured  into  genuine  bread,  in  the  ordinary  way,  would  yield  0,300  real  4-lb. 
loaves,  and  the  account  would  stand  as  follows,  taking  90  loaves,  weighing  really  4  lbs., 
as  the  ultimate  yield  of  1  sack  of  good  household  flour,  of  the  quality  and  price  above 
alluded  to : — 

£y  the  Ordinary  Process. 

RETURNS. 

£         .■!.       d. 

6,300  loaves  (4  lbs.)  at  7(?. 183     15     0 

*  It  is  absolutely  necessary  thus  to  establisli  a  dislinction  bctwocn  four-pounds  and  qu.artcrn  loaves, 
because  the  latter  very  seldom  indeed  have  that  weight,  and  this  deficiency  is,  in  fact,  one  of  the  ])rofits 
calculated  upon;  for,  although  the  Act  of  rarliament  (Will.  IV^  cap.  xxxvii.)  is  very  strict,  and  dii-ects 
(sect,  vii.)  that  bakers  dcliveiinf;  breail  by  cart  or  carriage  Khali  bo  provided  with  scales,  weights,  Ac, 
for  weighing  bread,  this  rrqui.silion  is  schfoni,  if  ever,  complied  with.  , 

There  arc,  of  course,  a  few  bakers  whoso  quartern  loaves  weigh  exactly  four  pounds,  but  the  immenso 
majority  are  from  four  to  six  ounces  short. 

Vol.  III.— 13 


lU  BREAD. 

EXPENSES. 

£        S.      d. 

70  sacks  of  household  flour  at  37s. 129  10  0 

Coals,  gas,  potatoes,  yeast,  salt,  wages,  and  other  baking  ex- 
penses, at  6s.  per  sack 17  10  0 

Rent,  taxes,  interest  of  capital,  and  general  expenses    -        -       24  10  0 


171     10     0 


Net  profit  on  1  week's  baking £12       50 

Si/  J^erkitis's  Process. 


6,300  loaves  (4  lbs.)  at  7c?. 


£ 

s.     d. 

- 

• 

183 

15  0 

£ 

s. 

d. 

129 

10 

0 

3 

10 

0 

1 

15 

0 

1 

7 

0 

1 

0 

0 

t) 

16 

0 

0 

4 

0 

24 

10 

0 

—  162 

12  0 

70  sacks  of  flour  at  37s. 

Yeast,  potatoes,  and  salt,  at  l.s\  per  sack         .... 

Coals  at  (>d.  per  sack 

Wages  of  a  man  per  week 

"  1  workman 

"  1  hand  

Wear  and  tear,  and  repairs 

Rent,  interest  on  capital,  (£1,500,)  taxes,  gas,  waste,  and  general 
expenses,  per  week 

£21     13     0 

In  Rolland's  process  the  profits  are  very  nearly  the  same  as  in  that  of  Perkins',  except 
the  amount  of  fuel  consumed  is  still  more  reduced,  and  does  not  amount,  it  is  stated,  to 
more  than  4M  per  sack,  which,  for  70  sacks,  is  £1  6s.  St?.,  instead  of  £1  15s.,  or  9s.  differ- 
ence between  the  two  methods  for  baking  that  quantity  of  flour. 

The  richness  or  nutritive  powers  of  sound  flour,  and  also  of  bread,  are  proportional  to 
the  quantity  of  gluten  they  contain.  It  is  of  great  importance  to  determine  this  point,  for 
both  of  these  objects  are  of  enormous  value  and  consumption  ;  and  it  may  be  accomplished 
most  easily  and  exactly,  by  digesting,  in  a  water-bath,  at  the  temperature  of  167°  F.,  1,000 
grains  of  "bread  (or  flour)  with  1,000  grains  of  bruised  barley  malt,  in  5,000  grains,  or  in  a 
little  more  than  half  a  pint,  of  water.  AVhen  this  mixture  ceases  to  take  a  blue  color  from 
iodine,  (that  is,  when  all  the  starch  is  converted  into  a  soluble  dextrine,)  the  gluten  left  un- 
changed may  be  collected  on  a  filter  cloth,  washed,  dried  at  a  heat  of  212°  F.,  and  weighed. 
The  color,  texture,  and  taste  of  the  gluten  ought  also  to  be  examined,  in  forming  a  judg- 
ment of  good  flour  or  bread. 

The  question  of  the  relative  value  of  white  and  of  brown  bread,  as  nutritive  agents,  is 
one  of  very  long  standing,  and  the  arguments  on  both  sides  may  be  thus  resumed : — 

The  advocates  of  brown  bread  hold — 

That  the  separation  of  the  white  from  the  brown  parts  of  wheat  grain,  in  making  bread, 
is  likely  to  be  baneful  to  health  ; 

That  the  general  belief  that  bread  made  with  the  finest  flour  is  the  best,  and  that  white- 
ness is  a  proof  of  its  quality,  is  a  popular  error ; 

That  whiteness  may  be,  and  generally  is,  communicated  to  bread  by  alum,  to  the  injury 
of  the  consumer ; 

That  the  miller,  in  refining  his  flour,  to  please  the  public,  removes  some  of  the  ingre- 
dients necessary  to  the  composition  and  nourishment  of  the  various  organs  of  our  bodies  ; 
so  that  fine  flour,  instead  of  being  better  than  the  meal,  is,  on  the  contrary,  less  nourishing, 
and,  to  make  the  case  worse,  is  also  more  difficult  of  digestion,  not  to  speak  of  the  enormous 
loss  to  the  population  of  at  least  25  per  cent,  of  branny  flour,  containing  from  60  to  70  per 
cent,  of  the  most  nutritious  part  of  the  flour,  a  loss  which,  for  London  only,  is  equal  to  at 
least  7,500  sacks  of  flour  annually  ; 

That  the  unwise  preference  given  so  universally  to  white  bread,  leads  to  the  pernicious 
.practice  of  mixing  alum  with  the  flour,  and  this  again  to  all  sorts  of  impositions  and  adul- 
terations ;  for  it  enables  the  bakers  who  are  so  disposed,  by  adding  alum,  to  make  bread 
manufactured  from  the  flour  of  inferior  grain  to  look  like  the  best  and  more  costly,  thus  de- 
frauding the  purchaser,  and  tampering  with  his  health. 

On  the  other  side,  the  partisans  of  white  bread  contend,  of  course,  that  all  these  asser- 
tions are  without* foundation,  and  their  reasons  were  summed  up  as  follows  in  the  Bakers' 
Gazette,  in  1849 :— 


BREAD.  195 

"  The  preference  of  the  public  for  white  bread  is  not  likely  to  be  an  absurd  prejudice, 
seeing  that  it  was  not  until  after  years  of  experience  that  it  was  adopted  by  them. 

"  The  adoption  of  white  bread,  in  preference  to  any  other  sort,  by  the  great  body  of  the 
community,  as  a  general  article  of  food,  is  of  itself  a  proof  of  its  being  the  best  and  most 
nutritious. 

"  The  finer  and  better  the  flour,  the  more  bread  can  be  made  from  it.  Fifty-six  pounds 
of  fine  flour  from  good  wheat  will  make  seventy-two  pounds  of  good,  sound,  well-baked 
bread,  the  bread  having  retained  sixteen  pounds  of  water.  But  bran,  either  fine  or  coarse, 
absorbs  little  or  no  water,  and  adds  no  more  to  the  bread  than  its  weight." 

And  lastly,  in  confirmation  of  the  opinion  that  white  bread  contains  a  greater  quantity 
of  nutriment  than  the  same  weight  of  brown  bread,  the  writer  of  the  article  winds  up  the 
white  bread  defence  with  a  portion  of  the  Report  of  the  Committee  of  the  House  of  Com- 
mons, appointed  in  1800,  "  to  consider  means  for  rendering  more  effectual  the  provisions 
of  13  Geo.  III.,  intituled 'An  Act  for  the  better  regulating  the  assize  and  making  of 
Bread.' " 

In  considering  the  propriety  of  recommending  the  adoption  of  further  regulations  and 
restrictions,  they  understood  a  prejudice  existed  in  some  parts  of  the  country  against  any 
coarser  sort  of  bread  than  that  which  is  at  present  known  by  the  name  of  "  fine  household 
bread,"  on  the  ground  that  the  former  was  less  wholesome  and  nutritious  than  the  latter. 
The  opinions  of  respectable  physicians  examined  on  this  point  are, — that  the  change  of  any 
sort  of  food  which  forms  so  great  a  part  of  the  sustenance  of  man,  might,  for  a  time,  aflfect 
some  constitutions ;  that  as  soon  as  persons  were  habituated  to  it,  the  standard  wheaten 
bread,  or  even  bread  of  a  coarser  sort,  would  be  equally  wholesome  with  the  fine  wheaten 
bread  which  is  now  generally  used  in  the  metropolis ;  but  that,  in  their  opinion,  the  fine 
wheaten  bread  would  go  farthtr  with  persons  who  have  no  other  food  than  the  same  quan- 
tity of  bread  of  a  coarser  sort. 

It  was  suggested  to  them,  that  if  only  one  sort  of  flour  was  permitted  to  be  made,  and  a 
different  mode  of  dressing  it  adopted,  so  as  to  leave  it  in  the  fine  pollards,  52  lbs.  of  flour 
might  be  extracted  from  a  bushel  of  wheat  weighing  60  lbs.,  instead  of  47  lbs.,  which  would 
afford  a  wholesome  and  nutritious  food,  and  add  to  the  quantity  5  lbs.  in  every  bushel,  or 
somewhat  more  than  Va-  On  this  they  remarked  that  there  would  be  no  saving  in  adopting 
this  proposition ;  and  they  begged  leave  to  observe,  if  the  physicians  are  well  founded  i.n 
their  opinions,  that  bread  of  coarser  quality  will  not  go  equally  far  with  fine  wheaten  bread, 
an  increased  consumption  of  wheaten  bread  would  be  the  consequence  of  the  measure. 

From  the  bakers'  point  of  view,  it  is  evident  that  all  his  S}'mpathies  must  be  in  favor  of 
the  water-absorbing  material,  and  therefore  of  the  fine  flour  ;  for  each  pound  of  water  added 
and  retained  in  the  bread  which  he  sells,  represents  this  day  so  many  twopences ;  but  the 
purchaser's  interest  lies  in  just  the  opposite  direction. 

The  question,  however,  is  not,  in  the  language  of  the  Committee  of  the  House  of  Com- 
mons of  those  days,  or  of  the  physicians  whom  they  consulted,  whether  a  given  weight  of 
wheaten  bread  will  go  farther  than  an  equal  weight  of  bread  of  a  coarser  sort ;  nor  whether 
a  given  weight  of  pure  flour  is  more  nutritious  than  an  equal  weight  of  the  meal  from  the 
same  wheat  used  in  making  brown  bread.  The  real  question  is, —  Whether  a  giceii  weight 
of  wheat  contains  more  nutriment  than  the  flopr  obtained  from  that  weight  of  tvhcat. 

The  inquiry  of  the  Committee  of  the  House  of  Commons,  and  the  defence  of  white  bread 
versfus  brown  bread,  resting,  as  it  does,  in  this  respect,  upon  a  false  ground,  is  therefore 
perfectly  valueless  ;  for  whatever  may  have  been  the  opinion  of  respectable  physicians  and 
of  committees,  either  of  those  days  or  of  the  present  times,  one  thing  is  certain — namely, 
that  bran  contains  only  9  or  10  per  cent,  of  woody  fibre,  that  is,  of  matter  devoid  of  nutri- 
tious property  ;  and  that  the  remainder  consists  of  a  larger  proportion  of  gluten  and  starch, 
fatty,  and  other  highly  nutritive  constituents,  with  a  few  salts,  and  water,  as  proved  by  the 
following  analysis  by  Millon  : — 

Composition  of  Wheat  Bran. 

Starch      -       • 52-0 

Gluten 14-9 

Sugar 1-0 

Fatty  matter 3*6 

Woody    " 9-7 

Salts 6-0 

Water 138 

100  0 
And  it  is  equally  certain  that  wheat  itself — I  mean  the  whole  grain — does  not  contain 
more   than  2  per  cent,  of  unnutritious,  or  woody  matter,  the  bran  being  itself  richer, 
weight  for  weight,  in  gluten,  than  the  fine  flour  ;  the  whole   meal  contains,  accordingly, 
more  gluten  than  the  fine  flour  obtained  therefrom.     The  relative  proportions  of  gluten 


190  BREAD. 

in  tlie  whole  grain,  in  bran,  and  in  flour  of  the  same  sample  of  wheat,  were  represented 
by  the  late  Professor  Johnston  to  be  as  follows : — 

Gluten  of  Wheat. 

Whole  grain 12  per  cent. 

Whole  bran 14  to  18         " 

Fine  flour 10         " 

Now,  whereas  a  bushel  of  wheat  weighing  CO  lbs.  produces,  according  to  the  mode  of 
manufacturing  flour  for  London,  4Y  lbs. — that  is,  '78  per  cent,  of  flour,  the  rest  being  bran 
and  pollards ;  if  we  deduct  2  per  cent,  of  woody  matter,  and  1  ^  per  cent,  for  waste  in 
grinding  at  the  mill,  the  bushel  of  (30  lbs.  of  wheat  would  yield  58  lbs.,  or  at  least  96f  per 
cent,  of  nutritious  matter. 

It  is,  therefore,  as  clear  as  any  thing  can  possibly  be,  that  by  using  the  whole  meal  in- 
stead of  only  the  fine  flour  of  that  wheat,  there  will  be  a  difference  of  about  Ve  in  the  pro- 
duct obtained  from  equal  weights  of  wheat. 

In  a  communication  made  to  the  Royal  Institute  ncaily  four  years  ago,  M.  Mfege  Mouri6s 
announced  that  he  had  found  under  the  envelope  of  the  grain,  iu  the  internal  part  of  the 
perisperm,  a  peculiar  nitrogenous  substance  capable  of  acting  as  a  ferment,  and  to  which  he 
gave  the  name  of  "  cerealine."  This  substance,  which  is  found  wholly,  or  almost  so,  in  the 
bran,  but  not  in  the  best  white  flour,  has  the  property  of  liquefying  starch,  very  much  in  the 
same  manner  as  diastase  :  and  the  decreased  firmness  of  the  crumb  of  brown  bread  is  re- 
ferred by  him  to  this  action.  The  coloration  of  bread  made  from  meal  containing  bran  is 
not,  according  to  M.  Mege  Mouries,  due,  as  has  hitherto  been  thought,  to  the  presence  of 
bran,  but  to  the  peculiar  action  of  cercalin ;  this  new  substance,  like  vegetable  casein  and 
gluten,  being,  by  a  slight  modification,  due  perhaps  to  the  contact  of  the  air,  transformed 
into  a  ferment,  under  the  influence  of  which  the  gluten  undergoes  a  great  alteration,  yield- 
ing, among  other  products,  ammonia,  a  brown-colored  matter  analogous  to  ulmine,  and  a 
nitrogenous  product  capable  of  transforming  sugar  into  lactic  acid.  51.  Mege  Mouries  having 
experimentally  established,  to  the  satisfaction  of  a  committee  consisting  of  MM.  Chevreul, 
Dumas,  Pelouze,  and  Peligot,  that  by  paralyzing  or  destroying  the  action  of  cerealin,  as 
described  in  the  specification  of  his  patent,  bearing  date  the  14th  of  June,  1856,  white 
bread,  having  all  the  characters  of  first  quality  bread,  may  be  made,  in  the  language  of  the 
said  specification,  "  with  using  either  all  the  white  or  raw  elements  that  constitute  either 
corn  or  rye,  or  with  such  substances  as  could  produce,  to  this  day,  but  brown  bread." 

Cerealin,  according  to  M.  Mfege  Mouries,  has  two  very  distinct  properties  :— the  first 
consists  in  converting  the  hydrated  starch  into  glucose  and  dextrine  ;  the  second,  which  is 
much  more  important  in  its  results,  transforms  the  glucose  into  lactic,  acetic,  butyric,  and 
formic  acid,  which  penetrate,  swell  up,  and  partly  dissolve  the  gluten,  rendering  it  pulpy 
and  emulsive,  like  that  of  rye  ;  producing,  in  fact,  a  series  of  decompositions,  yicldipg 
eventually  a  loaf  having  all  the  characteristics  of  bread  made  from  inferior  flour. 

In  order  to  convert  the  whole  of  the  farinaceous  substance  of  wheat  into  white  bread,  it 
is  therefore  necessary  to  destroy  the  cerealin ;  and  the  process,  or  series  of  processes,  by 
which  this  is  accomplished,  is  thus  descril>cd  by  M.  Mege  Mouries  in  his  specification  : — 

''  The  following  are  the  means  I  employ  to  obtain  my  new  product : — 

"  1st.  The  application  of  vinous  fermentation,  produced  by  alcoholic  ferment  or  yeast, 
to  destroy  the  ferment  that  I  call  '  cerealine,'  existing,  together  with  the  fragments  of  bran, 
in  the  raw  flour,  and  which,  in  some  measure,  produces  the  acidity  of  brown  bread  directly, 
whilst  it  destroys  indirectly  most  part  of  the  gluten. 

"  2dly.  The  thorough  purification  of  the  said  flour,  either  raw  or  mixed  with  bran, 
(after  dilution  and  fermentation,)  by  the  sifting  and  separating  of  the  farinaceous  liquid  from 
the  fragments  of  bran  disseminateil  by  the  millstone  into  the  inferior  products  of  corn. 

"  3dly.  The  employing  that  part  of  corn  producing  browni  lircad  in  the  rough  state,  as 
issuing  from  the  mill  after  a  first  grinding,  in  order  to  facilitate  its  purification  by  fermen- 
tation and  wet  sifting. 

"  4thly.  The  employing  acidulated  water  (by  any  acid  or  acid  salt)  in  order  to  prevent 
the  lactic  fermentation,  preserving  the  vinous  fermentation,  preventing  the  yellow  color 
from  turning  into  a  lirown  color,  (the  ulmic  acid,)  and  the  good  taste  of  corn  from  assuming 
that  of  brown  bread.  However,  instead  of  acidulated  water,  pure  water  may  be  employed 
with  an  addition  of  yeast,  as  the  acid  only  serves  to  facilitate  the  vinous  fermentation. 

"  Sthly.  The  grinding  of  the  corn  by  means  of  millstones  that  crush  it  thoroughly,  in- 
creasing thereby  the  quantity  of  foul  parts,  a  method  which  will  prove  very  bad  with  the 
usual  process,  and  very  advantageous  with  mine. 

"  Gthly.  The  application  of  corn  washed  or  strii)ped  by  any  suitable  means. 

"  7thly.  The  application  of  all  these  contrivances  to  wheat  of  every  description,  to  rye, 
and  other  grain  used  in  the  manufacture  of  Ijread. 

"  Sthly.  The  same  means  applied  to  the  manufacture  of  biscuits. 

"  I  will  now  describe  the  manner  in  which  the  said  improvements  are  carried  into  effect. 


BREAD 


197 


"  First  Instance.  ^Vhen  floxur  of  inferior  quality  is  made  use  of. — This  description  of 
flour,  well  known  in  trade,  is  bolted  or  sifted  at  73,  75,  or  80  per  cent.,  (a  mark  termed 
Scipion  mark  in  the  French  War  Department,)  and  yields  bread  of  middle  quality.  By 
applying  to  this  sort  of  flour  a  liquid  yeast,  rather  different  from  that  which  is  applied  to 
white  flour,  in  order  to  quicken  the  work  and  remove  the  sour  taste  of  bread,  a  very  nice 
quality  will  be  obtained,  which  result  was  quite  unknown  to  everybody  to  this  day,  and 
which  none  ever  attempted  to  know,  as  none  before  me  were  aware  of  the  true  causes  that 
produce  brown  bread,  &c. 

"  Now  to  apply  my  process  to  the  said  flour,  (of  inferior  mark  or  quality,)  I  take  a  part 
of  the  same — a  fourth  part,  for  instance — which  I  dilute  with  a  suitable  quantity  of  water, 
and  add  to  the  farinaceous  liquid  1  portion  of  beer  yeast  for  200  portions  of  water,  together 
with  a  small  quantity  of  acid  or  acid  salt,  sufficient  to  impart  to  the  said  water  the  property 
of  lightly  staining  or  reddening  the  test-paper,  known  in  France  by  the  name  of  papier  de 
touniesol.  When  the  liquid  is  at  full  working,  I  mix  the  remaining  portions  of  flour,  which 
are  kneaded,  and  then  allowed  to  ferment  in  the  usual  way.  The  yeast  applied,  which  is 
quite  alcoholic,  will  yield  perfectly  white  bread  of  a  very  nice  taste  ;  and  I  declare  that  if 
similar  yeast  were  ever  commended  before,  it  was  certainly  not  for  the  purpose  of  prevent- 
ing the  formation  of  brown  bread,  the  character  of  which  was  believed  to  be  inherent  to  the 
nature  of  the  very  flour,  as  the  following  result  will  suSicieutly  prove  it,  thus  divesting  such 
an  application  of  its  industrial  appropriation. 

"  Second  Instance.  \V/ie7i  raw  four  is-  made  use  of. — By  raw  flour,  I  mean  the  corn 
crushed  only  once,  and  from  which  10  to  15  per  cent,  of  rough  bran  have  been  separated. 
Such  flour  is  still  mixed  with  fragments  of  bran,  and  is  employed  in  trade  to  the  manufac- 
ture of  so-called  white  flour  and  bran  after  a  second  and  third  grinding  or  crushing.  In- 
stead of  that,  I  only  separate,  and  without  submitting  it  to  a  fresh  crushing,  the  rough  flour 
in  two  parts,  about  70  parts  of  white  flour  and  15  to  18  of  rough  or  coarse  flour,  of  which 
latter  the  yeast  is  made  ;  this  I  dilute  with  a  suitable  quantity  of  water,  sufficient  to  reduce 
the  whole  flour  into  a  dough,  say  50  per  cent,  of  the  whole  weight  of  raw  flour.  To  this 
mixture  have  been  previously  added  the  yeast  and  acid,  (whenever  acid  is  applied,  which  is 
not  indispensable,  as  before  stated,)  and  the  whole  is  allowed  to  work  for  6  hours  at  a  tem- 
perature of  77^  F.,  for  12  hours  at  68\  and  for  20  hours  at  59°,  thus  proportionally  to  the 
temperature.  While  this  working  or  fermentation  is  going  on,  the  various  elements  (cerea- 
line,  &c.)  which,  by  their  peculiar  action,  are  productive  of  brown  bread,  have  undergone 
a  modification  ;  the  rough  parts  are  separated,  the  gluten  stripped  from  its  pellicles  and  dis- 
aggregated, and  the  same  flour  which,  by  the  usual  process,  could  have  only  produced  deep 
brown  bread,  will  actually  yield  first-rate  bread,  far  superior  to  that  sold  by  bakers,  chiefly 
if  the  fragments  of  bran  are  separated  by  the  following  process,  which  consists  in  pouring 
on  the  sieve,  described  hereafter,  the  liquid  containing  the  rough  parts  of  flour  thus  disag- 
gregated and  modified  by  a  well-regulated  fermentation. 

"  The  sieve  alluded  to,  which  may  be  of  any  form,  consists  of  several  tissues  of  different 
tightness,  the  closest  being  ever  arranged  underneath  or  the  most  forward,  when  the  sieve 
is  of  cylindrical  or  vertical  form,  is  intended  to  keep  back  tlie  fragments  of  ))ran,  which 
would,  by  their  interposition,  impair  the  whiteness  of  bread,  and,  by  their  weight,  diminish 
its  nutritive  power.  The  sifted  liquid  is  white,  and  constitutes  the  yeast  with  which  the 
white  flour  is  mixed  after  being  separated,  so  as  to  make  a  dough  at  either  a  first  or  several 
workings,  according  to  the  baker's  practice.  This  dough  works  or  ferments  very  quickly, 
and  the  bread  resulting  therefrom  is  unexceptionable.  In  case  the  whiteness  or  neatness 
of  bread  should  be  looked  upon  as  a  thing  of  little  consequence,  a  broader  sieve  might  be 
employed,  or  even  no  sieve  used  at  all,  and  yet  a  very  nice  bread  be  obtained. 

"  The  saving  secured  by  the  application  of  my  process  is  as  follows  : — By  the  common 
process,  out  of  100  parts  of  wheat,  70  or  75  parts  of  flour  arc  extracled,  which  are  fit  to 
yield  either  white  or  middle  bread  ;  whilst,  by  the  improved  process,  out  of  100  parts  of 
wheat,  85  to  88  parts  will  be  obtained,  yielding  bread  of  supei'ior  quality,  of  the  best  taste, 
neatness,  and  nutritious  richness. 

"  In  case  new  yeast  cannot  be  easily  provided,  the  same  should  be  dried  at  a  temper- 
ature of  about  8G^  F.,  after  being  suitably  separated  by  means  of  some  inert  dust,  and  pre- 
vious to  being  made  use  of,  it  should  lie  dipped  into  10  parts  of  water,  lightly  sweetened, 
for  8  to  10  hours,  a  fit  time  for  the  li((uid  being  brought  into  a  full  fermentation,  at  which 
time  the  yeast  has  recovered  its  former  power.  The  same  process  will  hold  good  for  manu- 
ticturing  rye  bread,  only  25  per  cent.,  about,  of  course  bran  are  to  be  extracted.  For 
manufacturing  l)iscuits,  I  use  also  the  same  process,  only  the  dough  is  made  very  hard,  and 
immediately  taken  into  the  oven,  and  the  products  thus  obtained  are  far  sui)crior  to  the 
common  biscuits,  both  for  their  good  taste  and  preservation.  Should,  however,  an  old 
practice  exchide  all  manner  of  fermentation,  then  I  might  dilute  the  rougii  parts  of  flour  in 
either  acidulated  or  iu)n-acidulated  wafer,  there  to  l)e  left  to  work  for  the  same  time  as  l)c- 
fore,  then  sift  the  water  and  decant  it,  after  a  proper  settling  of  the  farinaceous  matters  of 
which  the  dough  is  to  be  made  ;  thus  the  action  of  the  acid,  decantation,  and  sifting,  would 


198 


BEEAD. 


effectively  remove  all  causes  of  alteration,  which  generally  impair  the  biscuits  made  of  in- 
ferior flour. 

"  The  apparatus  required  for  this  process  is  very  plain,  and  consists  of  a  kneading- 
trough,  in  which  the  foul  parts  are  mixed  mechanically,  or  by  manual  labor,  with  the  liquid 
above  mentioned.  From  this  trough,  and  through  an  opening  made  therein,  the  liquid 
mixture  drops  into  the  fermenting  tub,  deeper  than  wide,  which  must  be  kept  tightly  closed 
during  the  fermenting  work.  At  the  lower  part  of  this  tub  a  cock  is  fitted,  which  lets  the 
li(iuid  mixture  down  upon  an  inclined  plane,  on  which  the  liquid  spreads,  so  as  to  be  equally 
distributed  over  the  whole  surface  of  the  sieve.  This  sieve,  of  an  oblong  rectangular  form, 
is  laid  just  beneath,  and  its  tissue  ought  to  be  so  close  as  to  prevent  the  least  fragments  of 
bran  from  passing  through  ;  it  is  actuated  by  the  hand,  or  rather  by  a  crank.  In  all  cases, 
that  part  of  the  sieve  which  is  opposite  to  the  cock  must  strike  upon  an  unyielding  body, 
for  the  purpose  of  shaking  the  pellicles  remaining  on  the  tissue,  and  driving  them  down 
towards  an  outlet  on  the  lower  part  of  the  sieve,  and  thence  into  a  trough  purposely  con- 
trived for  receiving  the  waters  issuing  from  the  sieve,  and  discharging  them  into  a  tank. 

"  The  next  operation  consists  in  diluting  those  pellicles,  or  rougher  parts,  which  could 
not  pass  through  the  sieve,  sifting  them  again,  and  using  the  white  water  resulting  there- 
from to  dilute  the  foul  parts  intended  for  subsequent  operations.  The  sieve  or  sieves  may 
sometimes  happen  to  be  obstructed  by  some  parts  of  gluten  adhering  thereto,  which  I  wash 
off  with  acidulated  water  for  silk  tissues,  and  with  an  alkali  for  metallic  ones.  This  washing 
method  I  deem  very  important,  as  its  non-application  may  hinder  a  rather  large  operation, 
and  therefore  I  wish  to  secure  it.  This  apparatus  may  be  liable  to  some  variations,  and  ad- 
mit of  several  sieves  superposed,  and  with  different  tissues,  the  broadest,  however,  to  be 
placed  uppermost. 

"  Among  the  various  descriptions  and  combinations  of  sieves  that  may  be  employed,  the 
annexed  figures  show  one  that  will  give  satisfactory  results : 


"  Fig.  87  is  a  longitudinal  section,  znAfirf.  88  an  end  view,  of  the  machine  from  which 
the  bran  is  ejected.  The  apparatus  rests  upon  a  cast-iron  framing,  «,  consisting  of  two 
cheeks,  kept  suitably  apart  l)y  tie  pieces,  b  ;  a  strong  cross-b.ar  on  the  upper  part  admits  a 
wood  cylinder  c,  circled  round  with  iron,  and  provided  with  a  wooden  cock,  d.  The  cylin- 
der, c,  receives  through  its  centre  an  arbor,  /'  provided  with  four  arms,  <?,  which  arbor  is  su]i- 
ported  by  two  cro.ss-bar.s,  ft  and  /«,  secured  by  means  of  bolts  to  the  uprights,  i.  Motion  is 
imparted  to  the  arbor,  /,  by  a  crank,  j,  l)y  pulleys  driven  by  the  endless  straps,  A',  and  by 
the  toothed  wheel,  /,  gearing  into  the  wheel,  in,  which  is  keyed  on  the  upper  end  of  the  ar- 
bor,/. IJenoath  the  cylinder,  <%  two  sieves,  7i  and  o,  are  borne  into  a  frame,/),  suspended 
on  one  end  to  two  chains,  q,  and  on  the  other  resting  on  two  guides  or  bearings,  r,  beneath 
which,  and  on  the  crank  shaft,  are  cams,  .<t,  by  which  that  end  of  the  frame  that  carries  the 
sieves  is  alternately  raised  and  lowered.  A  strong  spring,  n,  is  set  to  a  shaft  borne  by  the 
framing,  or,  whilst  a  ratchet-wheel  provided  with  a  clink,  allows  the  said  spring,  according 
to  the  requirements  of  the  work,  to  give  more  or  less  impulse  or  shaking  as  the  cams,  s,  are 
acting  upon  the  frame-sieve  carrying  the  sieve.     Beneath  the  said  frame  a  large  hopper,  t, 


BREAD.  199 

is  disposed,  to  receive  and  lead  into  a  tank  the  liquid  passing  through  the  sieves.  The  filter 
sieve  is  worked  as  follows  : — After  withdrawing,  by  means  of  bolting  hutches,  70  per  cent., 
about,  of  fine  flour,  I  take  out  of  the  remaining  30  per  cent,  about  20  per  cent,  of  groats, 
neglecting  the  remaining  10  i)er  cent.,  from  which,  however,  I  could  separate  the  httle  flour 
still  adhering  thereto,  but  I  deem  it  more  available  to  sell  it  ofl"  in  this  state.  I'  submit  the 
20  per  cent,  of  groats  to  a  suitable  vinous  fermentation,  and  have  the  whole  taken  into  the 
cylinder,  c,  there  to  be  stirred  by  means  of  the  arbor,  /,  and  the  arms,  e  ;  after  a  suitable 
stirring,  the  cock,  d,  is  opened,  and  the  liquid  is  let  out,  spread  on  the  uppermost  sieve,  n, 
which  keeps  back  the  coarsest  bran.  The  liquid  drops  then  into  the  second  sieve  or  filter, 
0,  by  which  the  least  fragments  are  retained ;  the  passage  of  the  liquid  through  the  filters 
is  quickened  by  the  quivering  motion  imparted  by  the  cams,  s,  to  the  frame  carrying  the 
sieve." 

The  advantages  resulting  from  such  a  process  are  obvious :  first,  it  would  appear — and 
those  experiments  have  been  confirmed  by  the  committee  of  the  Academie  des  Sciences, 
who  had  to  report  upon  them — that  no  less  than  from  16  to  17  per  cent,  of  white  bread  of 
superior  quality  call  be  obtained  from  wheat,  which  increase  is  not  due  to  water,  as  in  other 
methods,  but  is  a  true  and  real  one,  the  Commissioners  having  ascertained  that  the  bread 
thus  manufactured  did  not  contain  more  water  than  that  made  in  the  usual  way,  their  com- 
parative examinations  in  this  respect  having  given  the  following  results : — 

Xioss  by  dryiny  in  Air. 

Crumb.  Crust. 

Old  method 37-8     -  -      120 

New  method 37-5     -  -     14-0 

Difierence      -         -         -         -     00-3  2-0 

Another  experiment  by  Peligot : — 

Loss  by  drying  in  Air  at  218°  F. 

Crumb  and  Crust. 

New  method 34'9  per  cent. 

Old  method 311         " 

Difference 00-8 

Since  the  enrolment  of  his  Specification,  however,  M.  Mege  Mourifeg  has  made  an  im- 
provement, which  simplifies  considerably  his  original  process,  according  to  which  the 
destruction  of  the  cerealin,  as  we  saw,  was  effected  by  ordinary  yeast;  that  is  to  say,  by 
alcoholic  fermentation.  The  last  improvement  consists  in  preventing  cerealin  from  be- 
coming a  lactic  or  glucosic  ferment,  by  precipitating  it  with  common  salt,  and  not  allow- 
ing it  time  to  become  a  ferment.  In  effect,  in  order  that  cereahn  may  produce  the 
objectionable  effects  alluded  to,  it  must  first  pass  into  the  state  of  ferment,  and,  as  all 
nitrogenous  substances  require  a  certain  time  of  incubation  to  become  so,*  if,  on  the  one 
hand,  cerealin  be  precipitated  by  means  of  common  salt,  the  glucosic  action  is  neutral- 
ized ;  whilst,  on  the  other  hand,  the  levains  being  made  with  flour  containing  no  cerealin 
— that  is  to  say,  with  best  white  flour — if  a  short  time  before  baking  households  or  sec- 
onds are  added  thereto,  it  is  clear  that  time  will  be  wanting  for  it  (the  ferment)  to  become 
developed  or  organized,  and  that,  under  this  treatment,  the  bread  will  remain  white. 

The  application  of  these  scientific  deductions  will  be  better  understood  by  the  follow- 
ing description  of  the  process  : — 

100  parts  of  clean  wheat  are  ground  and  divided  as  follows : — 

Best  whites  for  leaven 40'0 

White  groats,  mixed  with  a  few  particles  of  bran         -  38'0 

White  groats,  mixed  with  a  larger  quantity  of  bran     -  8-0 

Bran  (not  used) 15o 

Loss 0*5 

102-0 

These  figures  vary,  of  course,  according  to  the  kind  of  wheat  used,  according  to  seasons, 
and  according  to  the  description  of  mill  and  the  distance  of  the  millstones  used  for  grinding. 

"  In  order  to  convert  these  products  into  bread,"  says  M.  Mege  Mouriiis,  "  a  leaven  is 
to  be  made  by  mixing  the  40  parts  of  best  flour  above  alluded  to,  with  20  parts  of  water, 
and  proceeding  with  it  according  to  the  mode  and  custom  adopted  in  each  locality.  This 
leaven,  no  matter  how  prepared,  being  ready,  the  8  parts  of  groats  mixed  with  the  larger 
quantity  of  bran  above  alluded  to,  are  diluted  in  45  parts  of  water,  in  which  0-6  parts  of 

*  Communication  of  M.  Mcgc  Mourics  to  the  Acadcinio  des  Sciences,  January,  1853. 


200 


BREAD. 


common  salt  have  been  previously  dissolved,  and  the  whole  is  passed  through  a  sieve,  which 
allows  the  Hour  and  water  to  pass  through,  but  retains  and  separates  the  particles  of  bran. 
The  watery  liquid  so  obtained  has  a  white  color,  is  flocculent,  and  loaded  with  cerealin  ;  it 
no  longer  possesses  the  property  of  liquefying  gelatinous  starch,  and  weighs  38  parts,  (the 
remainder  of  the  water  is  retained  in  the  bran,  which  has  swelled  up  in  consequence,  and 
remains  on  the  sieve.)  The  leaven  is  then  diluted  with  that  water,  which  is  loaded  with 
liest  flour,  and  is  used  for  converting  into  dough  the  38  parts  of  white  groats  above  alluded 
to  ;  the  dough  is  then  divided  into  suitable  portions,  and,  after  allowing  it  to  stand  for  one 
hour,  it  is  iinally  put  in  the  oven  to  be  baked.  As  the  operations  just  described  take  place 
at  a  temperature  of  25""  C,  (=  IT'  F.,)  the  one  hour  during  which  the  dough  is  left -to  itself, 
is  not  sufficient  for  the  cerealin  to  pass  into  the  state  of  ferment,  and  the  consequence  is  the 
production  of  white  bread.  Should,  however,  the  temperature  be  higher  than  that,  or  were 
the  dough  allowed  to  be  kept  for  a  longer  time  before  baking,  the  bread  produced,  instead 
of  bein"'  white,  would  be  so  much  darker,  as  tlie  contact  would  have  lastccl  longer.  By  this 
process,  100  parts  in  weight  of  wheat  yield  130  parts  of  dough,  and  finally,  115  parts  in 
weit^ht  of  bread,"  instead  of  100,  which  the  same  quantity  of  wheat  woirid  have  yielded  in 
the  u.sual  way.  This  is  supposing  that  the  grinding  of  the  wheat  has  been  eflected  with 
dose-set  millstones;  if  ground  in  the  usual  way,  the  average  yield  does  not  exceed  112 
parts  in  weight  of  bread. 

The  sub*anccs  which  are  now  almost  exclusively  employed  for  adulterating  bread,  are 
wafer,  alone  or  incorporated  with  rice,  or  water  and  aban  :  other  substances,  however,  are 
or  have  been  occasionally  used  for  the  same  purpose  ;  they  are,  Kulphate  of  copper,  carbo- 
nate of  magnesia,  sulphate  of  zinc,  carbonate  of  ammonia,  carbonate  and  bicarbonate  of  pM- 
ash,  carbonate  and  bicarbonate  of  soda,  chalk,  pjlastcr,  lime,  clay,  starch,  potatoes,  and 
other  fecula.     ■«•■ 

This  retention  of  water  into  bread  is  secured  by  underbaking,  by  the  introduction  of  rice 
and  feculas,  and  of  alum. 

Underbaking  is  an  operation  which  consists  of  keeping  in  the  loaf  the  water  which 
otlierwise  would  escape  while  baking ;  it  is,  therefore,  a  process  for  selling  water  at  the 
price  of  bread.  It  is  done  by  introducing  the  dough  into  an  oven  unduly  heated,  whereby 
the  gases  contained  in  the  dougli  at  once  expand,  and  swell  it  up  to  the  ordinary  dimen- 
sions, whilst  a  deep-burnt  crust  is  immediately  afterwards  formed  ;  which,  inasmuch  as  it  is 
a  bad  conductor  of  heat,  prevents  the  interior  of  the  loaf  from  being  thoroughly  baked,  and 
at  the  same  time  opposes  the  free  exit  of  the  water  contained  in  the  dough,  and  which  the 
heat  of  the  oven  partly  converts  into  steam  ;  while  the  crust  becomes  thicker  and  darker 
than  it  otherwise  should  be,  a  sensible  loss  of  nutritive  elements  being  sustained,  at  the 
same  time,  in  the  shape  of  pyrogenous  products  which  are  dissipated. 

The  proportion  of  water  retained  in  bread  by  underbaking  is  sometimes  so  large,  that  a 
baker  may  thus  obtain  as  much  as  106  loaves  from  a  sack  of  ilour. 

The  addition  of  boiled  rice  to  the  dough  is  also  pretty  frequently  used  to  increase  the 
yield  of  loaves  ;  this  substance,  in  fact,  absorbs  so  much  water,  that  as  many  as  116  quartern 
loaves  have  thus  been  obtained  from  one  sack  of  flour. 

From  a  great  number  of  experiments,  made  with  a  view  to  determine  the  normal  quan- 
tity of  water  contained  in  the  crumb  of  genuine  bread,  it  is  ascertained  that  it  amounts,  in 
new  bread,  from  38  at  least  to  at  most  47  per  cent. 

•  The  quantity  of  water  contained  in  bread  is  easily  determined  by  cutting  a  slice  of  it, 
weighing  500  grains,  for  example,  placing  it  in  a  small  oven  heated  by  a  gas-burner  or  a 
lamp  to  a  temperature  of  about  220°  F.,  until  it  no  longer  loses  weight ;  the  difference 
between  the  first  and  last  weighing  (that  is  to  say,  the  loss)  indicating,  of  course,  the  amount 
of  water. 

Alum,  however,  is  the  principal  adulterating  substance  used  by  bakers,  almost  without 
exception,  in  this  mptropoli:^  ;  as  was  proved  by  Dr.  Normanby,  in  his  evidence  before  the 
Select  Committee  of  the  House  of  Commons,  appointed  in  1855,  under  the  prcsidcnce  of 
Mr.  W.  Scholefield,  to  inquire  into  the  adulteration  of  food,  drinks,  and  drugs,  which  as- 
sertion was  corroborated  and  established  beyond  doubt  by  the  other  chemists  who  were 
examined  also  on  the  subject. 

The  introduction  of  alum  into  bread  not  only  enables  tlie  baker  to  give  to  bread  made 
of  flour  of  inferior  qualitv  the  whiteness  of  the  best  bread,  but  to  force  and  keep  in  it  a 
larger  quantity  of  water  than  could  otherwise  be  done.  We  shall  see  presently  that  this 
fact  has  been  denied,  and  on  what  grounds. 

The  quantity  of  alum  used  varies  exceedingly  ;  but  no  appreciable  effect  is  produced 
when  the  proportion  of  ahnn  introduced  is  less  than  1  in  900  or  1,000,  which  is  at  the  rate 
of  27  or  28  grains  in  a  quartern  loaf.  The  use  of  alum,  however,  has  become  so  universal, 
and  the  Act  of  Parliament  which  regulates  the  matter  has  so  long  been  considered  as  a  dead 
letter  from  the  trouljle,  and  chance  of  pecuniary  loss  which  it  entails  on  the  prosecutor 
should  his  accusation  prove  unsuccessful,  that  but  few,  and  until  quita  lately  none,  of  the 
public  officers  would  imdertake  the  discharge  of  a  duty  most  disagreeable  in  itself,  and  at 
the  same  time  full  of  risk. 


BREAD. 


201 


When  alum  is  used  in  making  bread,  one  of  the  two  following  things  may  happen : 
either  the  alum  will  be  decomposed,  a^  just  said,  iu  which  case  the  alumina  will,  of  neces- 
sit}',  bo  set  free  as  soon  as  digestion  will  have  decomposed  the  organic  matter  with  which  it 
was  combined ;  and  thus  it  is  presumable  that  either  alum  will  be  re-formed  in  the  stomach, 
or  that,  according  to  Liebig,  the  phosphoric  acid  of  the  phosphates  of  the  bread,  uniting 
with  the  alumina  of  the  alum,  will  forui  an  insoluble  phosphate  of  alumina,  and  the  benefi- 
cial action  of  the  phosphates  will,  coiiscciuently,  be  lost  to  the  system  ;  and  since  phosphoric 
acid  forms  with  alumina  a  compomid  hardly  decomposable  by  alkalis  or  acids,  this  may,  per- 
haps, explain  the  iudigestibility  of  the  London  bakers'  bread,  which  strikes  all  foreigners. — 
Letters  on  Cheniistn/. 

Tiie  last  defence  set  up  in  behalf  of  alumed  bread  to  be  noticed,  is,  that,  with  certain 
descriptions  of  flour,  bread  cannot  be  made  without  it ;  that,  by  means  of  alum,  a  large 
(jUAUtity  of  flour  is  made  available  for  human  food,  which,  without  it,  must  be  withdrawn, 
and  turned  to  some  other  less  important  uses,  to  the  great  detriment  of  the  population,  and 
partict'larly  of  the  poor,  who  would  be  the  first  to  suffer  from  the  increase  of  the  price  of 
Ijread  which  such  a  withdrawal  must  fatally  produce. 

Tiie  process  usually  adopted  for  the  detection  of  alum,  is  that  known  as  Kuhlman's  pro- 
cess, which  consists  in  incinerating  about  3,0U0  grains  of  bread,  porphyrizing  the  ashes  so 
obtained,  treating  them  by  nitric  acid,  evaporating  the  mixture  to  dryness,  and  diluting  the 
residue  with  about  300  grains  of  water,  with  the  help  of  a  gentle  heat ;  without  filtering,  a 
solution  of  caustic  potash  is  then  added,  the  whole  is  boiled  a  little,  filtered,  the  filtrate  is 
tested  with  a  solution  of  sal  ammoniac,  and  boiled  for  a  few  minutes.  If  a  precipitate  is 
formed,  it  is  not  adimina,  as  hitherto  thought,  and  stated  by  Kuhlman  and  all  other  chem- 
ists, but  phosp/iate  of  alumina^ — a  circumstance  of  great  importance,  not  in  testing  for  the 
presence  of  alumina,  but  for  the  determination  of  its  amount,  as  will  be  shown  further  on, 
when  entering  into  the  details  of  the  modifications  which  it  is  necessary  to  make  to  Kuhl- 
miu's  process. 

In  a  paper  read  in  April,  1858,  at  the  Society  of  Arts,  Dr.  Odling  stated  that  out  of  46 
examinations  of  ashes  furnished  him  by  Dr.  Gilbert,  and  treating  them  by  the  above  process, 
he  (Dr.  Odling)  obtained,  to  use  his  own  words,  "  in  21  instances,  the  celebrated  white  pre- 
cipitate said  to  be  indicative  of  alumina  and  alum,  so  that,  had  these  samples  been  in  the 
manufactured  instead  of  the  natural  state — had  the  wheat,  for  example,  been  made  into 
flour — I  should  have  been  justified,  according  to  the  authority  quoted,  in  pronouncing  it  to 
be  adulterated  with  alum.  But  a  subsequent  examination  of  the  precipitates  I  obtained, 
showed  that  in  reality  they  were  not  due  to  alumina  at  all.  Mr.  Kuhlman's  process,  as 
above  described,  is  possessed  of  rare  merits :  it  will  never  fail  in  detecting  alumina  when 
present,  and  will  often  succeed  in  detecting  it  when  absent  also.  The  idea  of  weighing  this 
oUa  podrida  of  a  precipitate,  and  from  its  weight  calculating  the  amount  of  alum  present, 
as  is  gravely  recommended  by  great  anti-adulteration  adepts,  is  too  preposterous  to  require 
a  moment's  refutation." 

Having  stated  the  question  in  dispute  as  it  at  present  stands,  we  must  leave  it  to  be  dis- 
cussed iu  another  place. 

In  order,  however,  to  render  the  process  for  the  detection  of  alum  in  bread  free  from 
objections,  the  following  method  is  recommended.  It  requires  only  ordinary  care,  and  it  is 
perfectly  accurate : — 

Cut  the  loaf  in  half;  take  a  thick  slice  of  crumb  from  the  middle,  carefully  trimming 
the  edges  so  as  to  remove  the  crust,  or  hardened  outside,  and  weigh  off  1,500  or  3,000 
grains  of  it ;  crumble  it  to  powder,  or  cut  it  into  slices,  and  expose  them,  on  a  sheet  of 
jtlatinum  tray  turned  up  at  the  edges,  to  a  low  red  heat,  until  fumes  are  no  longer  evolved, 
and  the  whole  is  reduced  to  charcoal,  which  will  require  from  twenty  to  forty  minutes,  ac- 
cording to  the  quantity;  transfer  the  charcoal  to  a  mortar,  and  reduce  it  to  fine  powder; 
put  now  this  finely-pulverized  charcoal  back  again  on  the  platinum  foil  tray,  and  leave  it  ex- 
jiosed  thereon  to  a  dark  cherry-red  heat  until  reduced  to  gray  ashes,  for  which  purpose  gas- 
furnace  lamps  will  be  found  very  convenient.  Only  a  clierry-red  heat  should  be  applied, 
because  at  a  higher  temperature  the  ashes  might  fuse,  and  the  incineration  be  thus  retarded. 
Keiuove  the  source  of  heat,  drench  the  gray  ashes  with  a  concentrated  solution  of  nitrate  of 
ammonia,  and  carefully  reapply  the  heat;  the  last  portions  of  charcoal  will  tlu'reby  l)e 
burnt,  and  the  ashes  will  then  liave  a  white  or  drab  color.  Drench  them  on  the  tray  with 
moderately  strong  and  pure  hydrochloric  acid,  and  after  one  or  two  minutes'  standing,  wash 
the  contents  of  the  platinum  foil  tray  with  distilled  water,  into  a  porcelain  dish  ;  evaporate 
to  perfect  dryness,  in  order  to  render  the  silica  insoluble  ;  drench  the  perfectly  dry  residue 
with  strong  and  pure  nmriatic  acid,  and,  after  standing  for  five  or  six  minutes,  dilute  the 
wiiole  witli  water,  and  boil  ;  while  boiling,  add  carefully  as  much  carbonate  of  soda  as  is 
nciccssary  nearly,  but  not  quite,  to  saturate  the  aci<l,  so  that  the  li(|Uor  may  still  be  acid  ; 
add  as  much  pure  alcohol-potash  as  is  necessary  to  render  it  strongly  alkaline  ;  l)oil  the 
whole  for  about  three  or  four  minutes,  and  filter.  If  now,  after  sliglitly  supersaturating  the 
strongly  alkaline  filtrate  with  pure  muriatic  acid,  the  further  addition  of  a  solution  of  car- 


202  BREAD. 

bonate  of  ammonia  produces,  either  at  once  or  after  heating  it  for  a  few  minutes,  a  light, 
white  riocculent  precipitate,  it  is  a  sign  of  the  presence  of  alumina,  the  identity  of  which  is 
confirmed  by  collecting  it  on  a  filter,  putting  a  small  portion  of  it  on  a  platinum  hook,  or 
on  charcoal,  heating  it  thereon,  moistening  the  little  mass  with  nitrate  of  cobalt,  and  again 
strongly  heating  it  before  the  blowpipe  ;  when  if,  without  fusiny,  it  assumes  a  beautiful  blue 
color,  the  jwesence  of  alumina  is  coiroborated.  If  the  operator  possesses  a  silver  capsule, 
he  will  do  well  to  use  it  instead  of  a  porcelain  one  for  boiling  the  mass  with  pure  caustic 
alcohol-potash,  in  order  to  avoid  all  chance  of  any  silica  (from  the  glaze)  becoming  dissolved 
by  the  potash,  and  afterwards  simulating  the  presence  of  alumina,  though,  if  the  boiling  be 
not  protracted,  a  porcelain  capsule  is  quite  available.  It  is,  however,  absolutely  necessary 
that  lie  should  w^q  potassc  a  fa/co/iol,  for  ordinary  caustic  potash  alwai/s  contains  some,  and 
occasionally  considerable,  quantities  of  alumina,  and  is  totally  unsuited  for  such  an  investi- 
gation. Even  poiasse  il  Valcohol  retains  traces  of  silica,  either  alone,  or  combined  with 
alumina  ;  so  that  for  this,  and  other  reasons  which  will  be  explained  presently,  an  extrava- 
gant quantity  of  it  should  not  be  used. 

La.stly,  carbonate  of  ammonia  is  preferable  to  caustic  ammonia  for  precipitating  the 
alumina,  since  that  earth  is  far  from  being  insoluble  in  caustic  annnonia. 

The  liquor  from  which  the  alumina  has  been  separated  should  now  be  acidified  with  hy- 
drochloric acid,  and  tested  with  chloride  of  bai-ium,  which  should  then  yield  a  copious  pre- 
cipitate of  sulphate  of  barytcs. 

The  only  precipitate  which  can,  under  the  circumstances  of  the  experiment,  simulate 
alumina,  is  the  jjhosphato  of  that  earth,  which  behaves  with  all  reagents  as  pure  alumina. 
Such  a  precipitate,  therefore,  if  taken  account  of  as  pure  alumina,  would  altogether  vitiate  a 
quantitative  analysis  if  the  amount  of  alum  were  calculated  from  it ;  but  the  proof  that  a 
certain  quantity  of  alum  had  been  used  in  the  bread  from  which  it  had  been  obtained  would 
remain  unshaken  ;  since  alumina,  whether  in  that  state  or  in  that  of  its  phosphate,  could 
not  have  been  found  except  a  salt  of  alumina — to  wit,  alum — had  been  used  by  the  baker. 
When,  therefore,  the  exact  amount  of  alumina  has  to  be  deteniiined,  the  precipitate  in 
question  should  be  submitted  to  further  treatment  in  order  to  separate  the  alumina ;  and 
this  can  be  done  easily  and  rapidly  by  dissolving  the  precipitate  in  nitric  acid,  adding  a  little 
metallic  tin  to  the  liquor,  and  boiling.  The  tin  becomes  rapidly  oxidized,  and  remains  in 
the  state  of  an  insoluble  white  powder,  which  is  a  mixture  of  peroxide  of  tin  and  of  phos- 
phate of  tin,  at  the  expense  of  all  the  phosphoric  acid  of  any  earthy  phosphate  which  may 
have  been  present.  The  whole  mass  is  evaporated  to  dryness,  and  the  dry  residue  is  then 
treated  by  water  and  filtered,  in  order  to  separate  the  insoluble  white  powder,  and  the  fil- 
trate which  contains  the  alumina  should  now  be  supersaturated  with  carbonate  of  ammonia. 
If  a  precipitate  is  formed,  it  is  pure  alumina.  The  white  insoluble  powder,  after  wash- 
ing, may  be  dissolved  in  hydrochloric  acid,  and  after  diluting  the  solution  with  water,  the 
tin  may  be  precipitated  therefrom  by  passing  through  it  a  stream  of  sulphuretted  hydrogen 
to  super.saturation,  leaving  at  rest  for  ten  or  twelve  hours,  filtering,  boiling  the  filtrate  until 
all  odor  of  sulphuretted  hydrogen  has  disappeared  ;  an  excess  of  nitrate  of  silver  is  then 
added,  and  the  liquor  filtered,  to  separate  the  chloride  of  silver  produced,  and  exactly  neu- 
tralizing the  filtrate  with  ammonia ;  and  if  a  lemon-yellow  precipitate  is  produced,  immedi- 
ately soluble  in  the  slightest  excess  of  either  ammonia  or  nitric  acid,  it  is  basic  phosphate 
of  silver,  (3AgO,)  PhO^,  the  precipitate  obtained  in  the  first  instance  being  thus  proved  to 
be  phosphate  of  alumina.  The  pure  alumina  obtained  may  now  be  collected  on  a  filter, 
wasiied  with  boiling  water,  thoroughly  dried,  and  then  ignited  and  weighed.  One  grain  of 
alumina  represents  9'027  grains  of  crystallized  alum. 

In  testing  bread  for  alum,  it  should  be  borne  in  mind,  however,  that  the  water  used  for 
making  the  dough  generally  contains  a  certain  quantity  of  sulphates,  and  that  a  precipitate 
of  sulphate  of  barytes  will  therefore  be  very  frequently  obtained,  though  much  less  consid- 
erable than  when  alum  has  been  used.  Some  waters  called  "  selenitous  "  contain  so  much 
sulphate  of  lime  in  solution,  that  if  they  were  used  in  making  the  dough,  chloride  of  barium 
would  afford,  of  course,  a  considerable  precipitate.  For  these  reasons,  therefore,  the  sepa- 
ration and  identification  of  alumina  are  the  only  reliable  proofs ;  because,  as  that  earth  does 
not  exist  normally  in  any  shape  in  wheat  or  common  salt  otherwise  than  in  traces,  the  proof 
that  alum  has  been  used  becomes  irresistible  when  we  find,  on  the  one  hand,  alumina,  and, 
on  the  other,  a  more  considerable  amount  of  sulphate  of  barytes  than,  except  under  the 
most  extraordinary  circumstances,  genuine  bread  would  yield. 

Stilp/inte  of  copper,  like  alum,  possesses  the  property  of  hardening  gluten,  and  thus, 
with  a  Hour  of  inferior  quality,  bread  can  be  made  of  good  appearance,  as  if  a  superior  flour 
had  been  u.scd. 

Lime  water  has  been  recommended  by  Liebig  as  a  means  of  improving  the  bread  made 
from  inferior  flour,  or  of  ilour  slightly  damaged,  by  keeping,  by  warehousing,  or  during 
transport  in  ships;  and  this  method,  at  the  meeting  of  the  British  Association  at  Glasgow, 
in  1855,  was  reported  as  having  been  tried  to  a  .somewhat  considerable  extent  by  the  bakers 
of  that  town,  and  with  success,  the  bread  kneaded  with  lime  water,  instead  of  pure  water. 


BREWING. 


203 


being  of  good  appearance,  good  taste,  good  texture,  and  free  from  the  sour  taste  which  in- 
variably belongs  to  alumed  or  even  to  genuine  bread  ; — admitting  all  this  to  be  true,  still 
we  should  deprecate  the  use  of  lime  water  in  bread,  because  it  cannot  be  done  with  impu- 
nity ;  however  small  the  dose  of  additional  matter  may  be  considered  when  taken  separately, 
it  is  always  large  when  considered  as  portion  of  an  article  of  food  like  bread,  consumed  day 
after  day  and  at  each  meal,  without  interruption.  To  allow  articles  of  food  to  be  tampered 
with,  under  any  circumstances,  is  a  dangerous  practice,  even  if  it  were  proved  that  it  can  be 
done  without  risk,  which,  however,  is  not  the  case  ;  and  Liebig  himself  has  said  that  chem- 
ists should  never  propose  the  use  of  chemical  products  for  culinary  preparations. 

The  quantity  of  ashes  left  after  the  incineration  of  genuine  bread,  varies  from  1  -5  at 
least  to  at  most  3  per  cent.  ;  and  if  the  latter  quantity  of  ashes  be  exceeded,  the  excess  may 
safely  be  pronounced  to  be  due  to  an  artificial  introduction  of  some  saline  or  earthy  matter. 

As  to  the  addition  to  bread  of  potatoes,  beans,  rice,  turnips,  maize,  or  Indian  corn, 
which  has  occasionally  been  practised  to  a  considerable  extent,  especially  in  years  of  scarcity, 
it  is  evident  that  they  may  be,  and  are  actually  permitted  under  the  Act  of  Parliament, 
Will.  IV.,  cap.  27,  sect.  11.  As  may  be  seen  below,  bread  in  which  these  ingredients 
replace  a  certain  quantity  of  flour,  Ls,  of  course,  perfectly  wholesome  ;  but  as  a  given  weight 
of  it  contains  less  nourishment  than  pure  wheat  bread,  it  is  clear  that  if  the  mixed  bread 
were  sold  under  the  name,  or  at  the  price,  of  wheat  bread,  it  would  be  a  fraud  on  the  pub- 
lic, and  more  especially  upon  the  poor ;  but  the  admixture  is  not  otherwise  objectionable. 

In  his  "  New  Letters  on  Chemistry,"  Liebig  makes  the  following  remarks  on  the  sub- 
ject :—  f 

"  The  proposals  which  have  hitherto  been  made  to  use  substitutes  for  flour,  and  thus 
diminish  the  price  of  bread  in  times  of  scarcity,  prove  how  much  the  rational  principles  of 
hygiene  are  disregarded,  and  how  unknown  the  laws  of  nutrition  are  still. 

"  It  is  with  food  as  with  fuel.  If  we  compare  the  price  of  the  various  kinds  of  coals,  of 
wood,  of  turf,  we  shall  find  that  the  number  of  pence  paid  for  a  certain  volun^e  or  weight  of 
these  materials  is  about  proportionate  to  the  number  of  degrees  of  heat  which  they  evolve 
in  burning.  .  .  .  The  mean  price  of  food  in  a  large  country  is  ordinarily  the  criterion 
of  its  nutritive  value.  .  .  .  Considered  as  a  nutritive  agent,  rye  is  quite  as  dear  as 
wheat ;  such  is  the  case,  also,  with  rice  and  potatoes ;  in  fact,  no  other  flour  can  replace 
wheat  in  this  respect.  In  times  of  scarcity,  however,  these  ratios  undergo  modification,  and 
potatoes  and  rice  acquire  then  a  higher  value,  because,  in  addition  to  tlieir  natural  value  as 
respiratory  food,  another  value  is  superadded,  which,  in  times  of  abundance,  is  not  taken 
into  account. 

"  The  addition  to  wheat  flour  of  potato  starch,  of  dextrine,  of  the  pulp  of  turnips,  gives 
a  mixture,  the  nutritive  value  of  which  is  equal  to  that  of  potatoes,  or  perhaps  less  ;  and  it 
is  evident  that  one  cannot  consider  as  an  improvement  this  transformation  of  wheat  flour 
into  a  food  having  only  the  same  value  as  rice  or  potatoes.  The  true  problem  consists  in 
communicating  to  rice  and  to  potatoes  a  power  equal  to  that  of  wheat  flour,  and  not  in 
doing  the  reverse.  At  all  events  it  is  always  better  to  cook  potatoes  by  themselves,  and 
eat  them,  than  with  bread  ;  the  Legislatio'c  should  even  prohibit  their  addition  to  bread^  on 
account  of  the  fraud  which  the  permission  must  inevitably  lead  to." 

The  detection  of  potato  starch,  of  beans,  peas,  Indian  corn,  rice,  and  other  feculas, 
which  is  so  easily  effected  by  means  of  the  microscope  in  flour,  is  exceedingly  difficult,  if 
not  impossible,  in  bread.  Bread  which  has  been  made  of  flour  mixed  with  Indian  corn  is 
harsher  to  the  touch,  and  has  frequently  a  slight  yellowish  color,  and,  when  moistened  with 
solution  of  potash  of  ordinary  strength,  a  yellow  or  greenish-yellow  tinge  is  developed. — A.  N. 

BREWING.  {Braaser,  Fr.  ;  Braucn,  Germ.)  The  art  of  makiiig  beer,  or  an  alcoholic 
liquor,  from  a  fermented  infusion  of  some  saccharine  and  amylaceous  substance  with  water. 
For  a  description  and  analysis  of  which,  and  of  the  substances  usually  employed  in  its  fer- 
mentation, see  the  article  Bker. 

The  processes  of  brewing  may  be  classed  under  three  heads  : — the  mashing,  the  boiling, 
and  the  fermentation. 

For  the  principles  which  should  guide  the  brewer  in  the  conduct  of  these  operations,  wo 
refer  to  the  article  Beer,  where  it  will  be  seen  that  the  ultimate  success  of  the  entire  scries 
depends  greatly  on  the  regulation  of  the  temperature,  the  duration,  and  the  proper  manage- 
ment of  the  initial  process  of  mashing. 

With  regard  to  temperature,  the  brewer  must  not  only  regulate  the  heat  of  the  water 
for  the  first  mnsh  by  the  color,  age,  and  quality  of  the  malt,  whether  pale,  amber,  or  brown, 
but  he  should  also  mark  the  temperature  of  the  atniosi)here  as  influencing  that  of  the  malt, 
and  the  absorption  of  the  heat  Ijy  the  utensils  employed  ;  remarking  tliat  well-mellowed  and 
brown  malt  will  bear  a  higher  mashing  heat  than  pah'  or  newly  dried,  and  that  the  best 
results  are  produced  when  the  mash  can  be  maintained  at  an  equable  temperature,  from 
160'  to  165'. 

The  duration  of  the  mash  must  also  have  reference  to  the  required  quality  of  the  beer, 
whether  intended  for  keeping  some  time  in  store,  or  for  present  use,  as  influencing  the 


20-i 


BREWING. 


relative  proportions  of  dextrine  and  sugar.     The  following  table,  by  Levesquc,  •will  exem- 
plify the  foregoing  remarks. 

The  first  eolumn  gives  the  temperature  of  the  air  at  the  time  of  mashing. 

The  second  colunm  shows  the  heat  of  the  water,  the  quantity  used,  and  the  resulting 
heat  of  the  mass — noting,  that  if  the  water  has  been  let  into  the  mash-tun,  at  the  boiling 
point,  and  allowed  to  cool  down,  or  the  vessel  has  been  thoroughly  warmed  before  the  com- 
nicncenient  of  the  process,  the  heat  may  be  taken  several  degrees  lower. 

The  third  column  shows  the  time  for  the  standing  of  the  mash  ;  but  this  will  be  modi- 
fied, as  before  stated,  by  the  quality  of  the  extract  required. 

The  bulk  of  the  materials  used  must  also  enter  into  the  consideration  of  the  tenifierature, 
as  a  large  body  of  malt  will  attain  the  required  temperature  with  a  mashing  heat  lower  than 
a  small  quantity  ;  the  powers  of  chemical  action  and  condensation  of  heat  being  increased 
with  increase  of  volume. 

Donovan,  speaking  of  the  temperature  to  be  employed  in  mashing,  lays  down  the  fol- 
lowing as  a  general  rule  : — For  well-dried  pale  malt,  the  heat  of  the  first  mashing  liquor 
may  be,  but  should  never  exceed,  170  ;  the  heat  of  the  second  may  be  180° ;  and,  for  a 
third,  the  heat  may  be,  but  need  never  exceed,  185\ 

The  quantity  of  water,  termed  liquor,  to  be  employed  for  mashing,  depends  upon  the 
greater  or  less  strength  to  be  given  to  the  beer,  but,  in  all  cases,  from  one  barrel  and  a  hall 
to  one  barrel  and  three  firkins  is  sufficient  for  the  first  stiff  mashing,  but  more  liquor  may 
be  added  after  the  midt  is  thoroughly  wetted. 

The  grains  of  the  crushed  malt,  after  Uie  wort  is  drawn  off,  retain  from  32  to  40  gallons 
of  water  for  every  quarter  of  malt.  A  further  amount  must  be  allowed  for  the  loss  by 
evaporation  in  the  boiling  and  cooling,  and  the  waste  in  fermentation,  so  that  the  amount 
of  liquor  required  for  the  mashing  will,  in  some  instances,  be  double  that  of  the  finished 
beer,  but  in  general  the  total  amount  will  be  reduced  about  one-third  during  the  various 
processes.       , 

Table  of  Mashing  Temperatures. 


Brown 

^■ 

^. 

Pale 

Malt. 

< 

1      "^       ■ 

< 

I lent  of 

u> 

ti 

.c 

« 

1 

u 

'      a 

s 

XInsh, 

"2 

*o 

Hcnt  c 

Mnsh, 

••5 

o 

Hest  of  Jlash, 

•a 

o 

Heat  of 

Mash, 

-^ 

= 

146°  to 

a 

14.5°  to  147°. 

£ 

144°  to  146°. 

§ 

£ 

143°  to  145°. 

5 

£ 

148°. 

Oi 

'  1 

in 

S 

02 

g 

i" 

f>  FirkiDS 

E 

'    s 

1  Fitkins 

8  Firkins 

1 

E 

9  Firkins 

10  Firkins 

1 

11  Firkins 

12  Firkins 

1 

1     H- 

per  Qr. 

H 

H 

per  Qr. 

per  Qr. 

P 

t- 

per  Qr. 

per  Qr 

t- 

per  Qr. 

per  Qr. 

P 

ll--:,l, 

H.  M. 

Fah. 

H;  M. 

Fnh. 

H.  M. 

Fah. 

H.  M 

i     10" 

197-00 

4-00 

'    10° 

1S9-00 

184-00 

300 

10° 

178-00 

175  00 

2-00 

10° 

172-00 

170-00 

1-00  1 

15 

195-17 

4-00 

;    15 

1S7-42 

182  59 

3-00 

15 

176-84 

173  92 

2-00 

15 

171-00 

169-19 

1-00 

?n 

193-34 

4.00 

20 

1S5-84 

181-18 

3  00 

20 

175-68 

172-84 

2-UO 

20 

17000 

168-28 

1-00 

'>'. 

191-51 

400 

25 

1S4-26 

179-77  J3-00 

25 

174-52 

171-70 

2  00 

25 

1G9-00 

167-37 

1-00  1 

so 

1S9-6S 

4-00 

'  30 

1S2-6S 

178  3G  13-00 

30 

173-36 

170-G8 

2-(!0 

30 

IGS-CO 

166-46 

1-00] 

.So 

1S7-85 

4  00 

i  35 

lSO-10 

176-95 

■3  00 

35 

172-20 

109  60 

2-00 

35 

167-00 

165  55 

1-00 

40 

1SG03 

4-00 

1  40 

179-52 

175-54 

300 

40 

171-04 

108-52 

2-00 

40 

166  00 

164-64 

1-00 

45 

1S4-19 

4  00 

45 

177-94 

174-13 

3  00 

45 

169-88 

1G7  44 

2  00 

45 

165-00 

163-78 

1-00 

O'l 

lS-2-36 

4-00 

!  50 

176-3C 

172-72 

3-00 

50 

16S-72 

1G6  8G 

2-00 

50 

164-00 

102-82 

100 

1   .')5 

ISO -53 

400 

I  55 

174-73 

171-81 

3  00 

55 

107  56 

165-28 

2-00 

55 

163-00 

161  91 

1-00  ' 

1   CO 

17S-70    3  40 

!  fio 

173-20 

169-90 

2-45 

60 

166-40 

164-20 

1-50 

60 

16200 

161-00 

0-55 

i  r>5 

17GS7    3-20 

fi5 

171-62 

168-49 

2 -.30 

65 

165-24 

163-12 

1-40 

65 

161-00 

160-19 

0-50 

70 

17504    3-00 

70 

170-04 

167  07 

2-15 

70 

164-08 

162-04 

1-30 

70 

16000 

159-28 

0-45 

1  tipn 

t  of  the  Tap, 

'        Heat  of  the  Tap, 

Ilcat  of  the  Tap, 

Heat  of 

the  Tap, 

1       1 

14°  to  146°. 

143°  to  145'. 

1 

142°  to  144.° 

141°  t{ 

)143°. 

The  following  example  will  give  an  idea  of  the  proportions  for  an  ordinary  quality  of 
beer : — 

Suppose  13  imperial  quarters  of  the  best  pale  malt  be  taken  to  make  1,500  gallons  of 
beer,  the  waste  may  be  calculated  at  near  900  gallons,  or  2,400  gallons  of  water  will  be  re- 
quired in  ma.shing. 

As  soon  as  the  water  in  the  copper  has  attained  the  heat  of  14.'°  in  summer,  or  1G7°  in 
winter,  600  g.allons  of  it  are  to  be  run  of!  into  the  mash-tuh,  (which  has  {)reviously  been  well 
cleansed  or  scalded  out  w-ith  1  Killing  water.")  and  the  malt  gradually  liut  rapidly  thrown  in 
and  well  intermixed,  so  that  it  may  be  uniformly  moistened,  and  that  no  lumps  remain. 
After  continuing  the  agitation  for  about  half  an  hour,  more  lirpior,  to  the  amount  of  450 
gallons,  at  a  temperature  of  190°,  may  be  carefully  and  gradually  introduced;  (it  is  an  ad- 
vantage if  this  can  be  done  by  a  pipe  inserted  under  the  false  Iiottom  of  the  mash-tub,)  the 
agitation  lieing  continued  till  the  whole  assumes  an  equally  fluid  state,  taking  care  also  to 
allow  as  small  a  loss  of  temperature  as  possible  during  the  operation,  the  resulting-  temper- 
ature of  the  mass  being  not  less  than  143°,  or  more  than  148  . 


BREZILIN"  AND  BEEZILEIN.  205 

The  mash  is  then  covered  close,  and  allowed  to  remain  at  rest  for  an  hour,  or  an  hour 
and  a  half,  after  whicli  the  tap  of  the  mash-tub  is  gradually  opened,  and  if  the  wort  that 
first  flows  is  turbid,  it  should  be  carefully  returned  into  the  tun  until  it  runs  perfectly  limpid 
and  clear.     The  amount  of  this  first  wort  will  be  about  675  gallons. 

Seven  hundred  and  fifty  gallons  of  water,  at  a  temperature  from  180'  to  185°,  may  now 
be  introduced,  and  the  raasliing  operation  repeated  and  continued  until  the  mass  becomes 
uniformly  fluid  as  before,  the  temperature  being  from  lUif  to  170'.  It  is  then  again 
covered  and  allowed  to  rest  for  an  hour,  and  the  wort  of  the  first  mash  having  been  quickly 
transferred  from  the  underback  to  the  copper,  and  brought  to  a  state  of  ebullition,  the  wort 
of  the  second  mash  is  drawn  off  with  similar  precaution,  and  added  to  it.  A  third  quantity 
of  water,  about  COO  gallons,  at  a  temperature  of  185^  or  190^,  should  now  be  run  through 
the  goods  in  the  mash-tun  by  the  sparging  process,  or  any  means  that  will  allow  the  hot 
liquor  to  percolate  through  the  grains,  displacing  and  carrying  down  the  heavier  and  more 
valuable  products  of  the  first  two  mashings.  The  wort  is  now  boiled  with  the  hops  from 
one  to  two  hours. 

The  object  of  boiling  the  wort  is  not  merely  evaporation  and  concentration,  but  extrac- 
tion, coagulation,  and,  finally,  combination  with  the  hops  ;  purposes  which  are  better  accom- 
plished in  a  deep  confined  copper,  by  a  moderate  heat,  than  in  an  open,  shallow  pan,  with  a 
quick  fire.  The  copper,  being  encased  above  in  brickwork,  retains  its  digesting  tempera- 
ture much  longer  than  the  pan  could  do.  The  waste  steam  of  the  close  kettle,  moreover, 
can  be  economically  employed  in  communicating  heat  to  water  or  weak  worts  ;  whereas  the 
exhalations  from  an  open  pan  would  prove  a  nuisance,  and  would  need  to  be  carried  oft"  by 
a  hood.  The  boiling  has  a  four-fold  effect:  1,  it  concentrates  the  wort;  2,  during  the 
earlier  stages  of  heating,  it  converts  the  starch  into  sugar,  dextrine,  and  gum,  by  means  of 
the  diastase  ;  3,  it  extracts  the  substance  of  the  hops  diffused  through  the  wort ;  4,  it  co- 
agulates tlie  albuminous  matter  present  in  the  grain,  or  precipitates  it  by  means  of  the  tannin 
of  the  hops. 

The  degree  of  evaporation  is  regulated  by  the  nature  of  the  wort  and  the  quality  of  the 
beer.  Strong  ale  and  stout,  for  keeping,  require  more  boiling  than  ordinary  porter  or 
table-beer,  brewed  for  immediate  use.  The  proportion  of  the  water  carried  oft'  by  evapora- 
tion is  usually  from  a  seventh  to  a  sixth  of  the  volume.  The  hops  are  introduced  at  the 
commencement  of  the  process.  They  serve  to  give  the  beer  not  only  a  bitter  aromatic 
taste,  but  also  a  keeping  quality,  or  they  counteract  its  natural  tendency  to  become  sour — 
an  effect  partly  due  to  the  precipitation  of  the  albumen  and  starch,  by  their  resinous  and 
tanning  constituents,  and  partly  to  the  antifermentable  properties  of  their  lupuline,  bitter 
l)rinciple,  ethereous  oil,  and  resin.  In  these  respects,  there  is  none  of  the  bitter  plants  which 
can  be  substituted  for  hops  with  advantage.  For  strong  beer,  powerful  fresh  hops  should 
be  selected  ;  for  weaker  beer,  an  older  and  weaker  article  will  suffice. 

The  stronger  the  hops  are,  the  longer  time  they  require  for  extraction  of  their  virtues ; 
for  strong  hops,  an  hour  and  a  half  or  two  hours'  boiling  may  be  proper ;  for  a  weaker  sort, 
half  an  hour  or  an  hour  may  be  sufficient ;  but  it  is  never  advisable  to  push  this  process  too 
far,  lest  a  disagreeable  bitterness,  without  aroma,  be  imparted  to  the  beer.  In  some  brew- 
eries, it  is  the  practice  to  boil  the  hops  with  a  part  of  the  wort,  and  to  filter  the  decoction 
through  a  drainer,  called  the  jack  hop-back.  The  proportion  of  hops  to  malt  is  very 
various  ;  but,  in  general,  from  IJ  lbs.  to  li  lbs.  of  the  former  are  taken  for  100  lbs.  of  the 
latter  in  making  good  table  beer.  For  porter  and  strong  ale,  2  lbs.  of  hops  are  used,  or 
even  more ;  for  instance,  from  2  lbs.  to  2i  lbs.  of  hops  to  a  bushel  of  malt,  if  the  beer  be 
destined  for  the  consumption  of  India. 

During  the  boiling  of  the  two  ingredients,  much  coagulated  albuminous  matter  in  various 
states  of  combination,  makes  its  appearance  in  the  liquid,  constituting  what  is  called  the 
breaking  or  curdling/  of  the  wort,  when  numerous  minute  flocks  are  seen  floating  in  it. 
The  resinous,  bitter,  and  oily-ethereous  principles  of  the  hops  combine  with  the  sugar  and 
gum,  or  dextrine  of  the  wort ;  but  for  this  eftect  they  require  time  and  heat ;  showing  that 
the  boil  is  not  a  process  of  mere  evaporation,  but  one  of  chemical  reaction.  A  yellowish- 
green  pellicle  of  hop-oil  and  resin  appears  upon  the  surface  of  the  boiling  wort,  in  a  some- 
what frothy  form  :  when  this  disappears,  the  boiling  is  presumed  to  be  completed,  and  the 
beer  is  strained  oft"  into  the  cooler.  The  residuary  hops  may  be  pressed  and  used  for  an  in- 
ferior quality  of  beer;  or  they  may  be  boiled  with  fresh  wort,  and  be  added  to  the  next 
brewing  charge.' 

After  l)eing  strained  from  the  hops,  by  passing  through  the  false  l)()ttom  of  the  hop- 
jack,  and  allowed  to  rest  on  the  coolers  a  sufficient  time  to  deposit  the  greatest  jjortion  of 
the  flocks  separated  in  the  boiling,  the  cooling  process  is  rapidly  completed  by  the  action 
of  the  Jiefrifierator.     See  RKFuniEUATioN  of  Wouts,  vol.  ii. 

The  wort  is  then  ready  for  the  inoculation  of  the  yeast  and  the  commencement  of  the 
fermentative  process,  which  completes  the  finished  beer.     Sec  the  articles  Beku  and  Fici;- 

MKNTATION. R.   W.   II. 

BREZILIN  and  I3REZILEIX.  According  to  M.  Preisser,  the  coloring  matter  of  Brazil 
wood  {Brczilin)  is  an  oxide  of  a  base  Brezilein,  which  has  no  color. 


206 


BlilOK. 


BRICK.  (Brique,  Fr. ;  JSacksteine,  Ziegelsteine,  Germ.)  A  solid  rectangular  mass  of 
baked  clay,  employed  for  building  purposes. 

The  natural  mixture  of  clay  and  sand,  called  loam,  as  well  as  marl,  -which  consists  of 
lime  and  clay  with  little  or  no  sand,  are  the  materials  usually  employed  in  the  manufacture 
of  bricks. 

There  are  few  places  in  this  country  which  do  not  possess  alumina  in  combination  with 
silica  and  other  earthy  matters,  forming  a  clay  from  which  bricks  can  be  manufactured. 
That  most  generally  worked  is  found  on  or  near  the  surface  in  a  plastic  state.  Others  are 
hard  marls  on  the  coal  measure,  new  red  sandstone,  and  blue  lias  formations.  It  is  from 
these  marls  that  the  blue  bricks  of  Staffordshire  and  the  fire-bricks  of  Stourbridge  are  made. 
Marl  ha.s  a  greater  resemblance  to  stone  and  rock,  and  varies  much  in  color ;  blue,  red, 
yellow,  kc.  From  the  greatly  different  and  varying  character  of  the  raw  material,  there  is 
an  equal  difference  in  the  principle  of  preparation  for  making  it  into  brick ;  while  one 
merely  requires  to  be  turned  over  by  hand,  and  to  have  sufficient  water  worked  in  to  make 
it  subservient  to  manual  labor,  the  fire-clays  and  marls  must  be  ground  down  to  dust,  and 
worked  by  powerful  machinery,  before  they  can  be  brought  into  even  a  plastic  state.  Now 
these  various  clays  also  shrink  in  drying  and  burning  from  1  to  15  per  cent.,  or  more.  This 
contraction  varies  in  proportion  to  the  excess  of  alumina  over  silica,  but  by  adding  sand, 
loam,  or  chalk,  or  (as  is  done  by  the  London  brick-makers)  by  using  ashes  or  breeze — as  it 
is  technically  called — this  can  be  corrected.  All  clays  burning  red  contain  oxides  of  iron, 
and  those  having  from  8  to  10  per  cent.,  burn  of  a  blue,  or  almost  a  black  color.  The 
bricks  are  exposed  in  the  kilns  to  great  heat,  and  when  the  body  is  a  fire-clay,  the  iron, 
melting  at  a  lower  temperature  than  is  sufficient  to  destroy  the  bricks,  gives  the  outer  sur- 
face of  them  a  complete  metallic  coating.  Bricks  of  this  description  are  common  in  Staf- 
fordshire, and  when  made  with  good  machinery,  (that  is,  the  clay  being  very  finely  ground,) 
are  superior  to  any  in  the  kingdom,  particularly  for  docks,  canal  or  river  locks,  railway- 
bridges,  and  viaducts.  In  Wolverhampton,  Dudley,  and  many  other  towns,  these  blue 
bricks  are  commonly  employed  for  paving  purposes.  Other  clays  contain  lime,  and  no  iron ; 
these  burn  white,  and  take  less  heat  than  any  other  to  burn  hard  enough  for  the  use  of  the 
builder,  the  lime  acting  as  a  flux  on  the  silica.  Many  clays  contain  iron  and  lime,  with  the 
lime  in  excess,  when  the  bricks  are  of  a  light  dun  color,  or  white,  in  proportion  to  the 
quantity  of  that  earth  present ;  if  magnesia,  they  have  a  brown  color.  If  iron  is  in  excess, 
they  burn  from  a  pale  red  to  the  color  of  cast-iron,  in  i^roportion  to  the  quantity  of  metal. 

There  are  three  classes  of  brick  earths: — 

1st.  Plastic  clay,  composed  of  alumina  and  silica,  in  different  proportions,  and  contain- 
ing a  small  percentage  of  other  salts,  as  of  iron,  lime,  soda,  and  magnesia. 

2d.  Loams,  or  sandy  clays. 

8d.  Marls,  of  which  there  are  also  three  kinds ;  clayey,  sandy,  and  calcareous,  according 
to  the  proportions  of  the  earth  of  which  they  are  composed,  viz.,  alumina,  silica,  and  lime. 

Ahmiina  is  the  oxide  of  the  metal  aluminium,  and  it  is  this  substance  which  gives  tenac- 
ity or  plasticity  to  the  clay-earth,  having  a  strong  affinity  for  water.  It  is  owing  to  excess 
of  alumina  that  many  clays  contract  tfto  much  in  drying,  and  often  crack  on  exposure 
to  wind  or  sun.  By  the  addition  of  sand,  this  clay  would  make  a  better  article  than  we 
often  see  produced  from  it.  Clays  contain  magnesia  and  other  earthy  matters,  but  these 
vary  with  the  stratum  or  rock  from  which  they  are  composed.  It  would  be  impossible  to 
give  the  composition  of  these  earths  correctly,  for  none  are  exactly  similar ;  but  the  follow- 
ing will  give  an  idea  of  the  proportions  of  the  ingredients  of  a  good  brick  earth  :  silica, 
throe-fifths ;  alumina,  one-fifth  ;  iron,  lime,  magnesia,  manganese,  soda,  and  potash  forming 
the  other  one-fifth. 

The  clay,  when  first  raised  from  the  mine  or  bed,  is,  in  very  rare  instances,  in  a  state  to 
allow  of  its  being  at  once  tempered  and  moulded.  The  material  from  which  fire-bricks  are 
manufactured  has  the  appearance  of  ironstone  and  blue  lias  limestone,  and  some  of  it  is  re- 
markably hard,  so  that  in  this  and  many  other  instances,  in  order  to  manufacture  a  good 
article,  it  is  necessary  to  grind  this  material  down  into  particles  as  fine  as  possible. 

Large  quantities  of  bricks  are  made  from  the  surfiice  marls  of  the  new  red  sandstone  and 
l)lue  lias  formations.  These  also  require  thorough  grinding,  but  from  their  softer  nature  it 
can  l»e  effected  by  less  powerful  machinery. — Chamberlain. 

Recently,  some  very  valuable  fire-bricks  have  been  made  from  the  refuse  of  the  China 
Clay  Works,  of  Devonshire.  The  quartz  and  mica  left  after  the  Kaolin  has  been  washed 
out,  are  united  with  a  small  portion  of  inferior  clay,  and  made  into  bricks.  These  are  found 
to  resist  heat  well,  and  are  largely  employed  in  the  construction  of  metallurgical  works. 
See  Clay. 

The  principal  machines  which  have  })een  worked  in  brick-making  are  three — 1st,  the 
pug-mill  ;   2d,  the  wash-mill ;  3d,  the  rolling-mill. 

The  pug-mill  is  a  cylinder,  sometimes  conical,  generally  worked  in  a  vertical  position, 
with  the  large  end  up.  Down  the  centre  of  this  is  a  strong  revolving  vertical  shaft,  on 
which  are  hung  horizontal  knives,  inclined  at  such  an  angle  as  to  form  portions  of  a  screw, 


BKICK. 


2or 


that  is,  the  knives  follow  each  other  at  an  angle  forming  a  scries  of  coils  round  this  shaft. 
The  bottom  knives  are  larger,  and  vary  in  form,  to  throw  off  the  clay,  in  some  mills  verti- 
cally, in  others  horizontally.  Some  have  on  the  bottom  of  the  shaft  one  coil  of  a  screw, 
which  throws  the  clay  off  more  powerfully  where  it  is  wished  to  give  pressure. 

The  action  of  this  mill  is  to  cut  the  clay  with  the  knives  during  their  revolution,  and  so 
work  and  mix  it,  that  on  its  escape  it  may  be  one  homogeneous  mass,  without  any  lumps 
of  hard  untempered  clay  ;  the  clay  being  thoroughly  amalgamated,  and  in  the  toughest  state 
in  which  it  can  be  got  by  tempering.  This  mill  is  an  excellent  contrivance  for  the  purpose 
of  working  the  clay,  in  combination  with  rollers  ;  but  if  only  one  mill  is  worked,  it  is  not 
generally  adopted,  for,  although  it  tempers,  mixes,  and  toughens,  it  does  not  extract  stones, 
crush  up  hard  substances,  or  free  the  clay  from  all  matters  injurious  to  the  quality  of  the 
ware  when  ready  for  market.  This  mill  can  be  worked  by  either  steam,  water,  or  horse 
power ;  but  it  takes  much  power  in  proportion  to  the  quantity  of  work  which  it  performs. 
If  a  brick  is  made  with  clay  that  has  passed  the  pug-mill,  and  contains  stones,  or  marl  not 
acted  on  by  weather,  or  lime-shells,  (a  material  very  common  in  clays,)  or  any  other  extra- 
neous matter  injurious  to  the  brick,  it  is  apparent  from  the  action  of  this  mill  that  it  is  not 
removed  or  reduced.  The  result  is  this :  the  bricks  being,  when  moulded,  in  a  very  soft 
state  of  tempered  material,  or  mud,  considerably  contract  in  drying,  but  the  stones  or  hard 
substances  not  contracting,  cause  the  clay  to  crack  ;  and  even  if  they  should  not  be  suffi- 
ciently large  to  do  this  in  drying,  during  the  firing  of  the  bricks  there  is  a  still  further  con- 
traction of  the  clay,  and  an  expansion  of  the  stone,  from  the  heat  to  which  it  is  subjected, 
and  the  result  is  generally  a  faulty  or  broken  brick,  and,  on  being  drawn  from  the  kilns,  the 
bricks  are  found  to  be  imperfect. 

The  earth,  being  sufficiently  kneaded,  is  brought  to  the  bench  of  the  moulder,  who 
works  the  clay  into  a  mould  made  of  wood  or  iron,  and  strikes  off  the  superfluous  matter. 
The  bricks  are  next  delivered  from  the  mould,  and  ranged  on  the  ground  ;  and  when  they 
have  acquired  sufficient  firmness  to  bear  handling,  they  are  dressed  with  a  knife,  and  staked 
or  built  up  in  long  dwarf  walls,  thatched  over,  and  left  to  dry.  An  able  workman  will 
make,  by  hand,  5,000  bricks  in  a  day. 

The  different  kinds  of  bricks  made  in  England  are  principally  ^/ac^*  brickx^  graij  and  red 
stocks,  marl  faciwj  bricks,  and  cutting  bricks.  The  place  bricks  and  stocks  are  used  in 
common  walling.  The  marls  are  made  in  the  neighborhood  of  London,  and  used  in  the 
outside  of  buildings ;  they  are  very  beautiful  bricks,  of  a  fine  yellow  color,  hard,  and  well 
burnt,  and,  in  every  respect,  superior  to  the  stocks.  The  finest  kind  of  marl  and  red  bricks, 
called  cutting  bricks,  are  used  in  the  arches  over  windows  and  doors,  being  rubbed  to  a 
centre,  and  gauged  to  a  height. 

Bricks,  in  this  country,  are  generally  baked  either  in  a  clamp  or  in  a  kiln.  The  latter 
is  the  preferable  method,  as  less  waste  arises,  less  fuel  is  consumed,  and  the  bricks  are  sooner 
burnt.  The  kiln  is  usually  13  feet  long,  by  10^  feet  wide,  and  about  12  feet  in  height. 
The  walls  are  one  foot  two  inches  thick,  carried  up  a  little  out  of  the  perpendicular,  inclined 
towards  each  other  at  the  top.  The  bricks  are  placed  on  flat  arches,  having  holes  left  in 
them  resembling  lattice-work  ;  the  kiln  is  then  covered  with  pieces  of  tiles  and  bricks,  and 
some  wood  put  in,  to  dry  them  with  a  gentle  fire. 

This  continues  two  or  three  days  before  they  are  ready  for  burning,  which  is  known  by 
the  smoke  turning  from  a  darkish  color  to  semi-transparency.  The  mouth  or  mouths  of  the 
kiln  are  now  dammed  up  with  a  s/iinlog,  which  consists  of  pieces  of  bricks  piled  one  upon 
another,  and  closed  with  wet  brick  earth,  leaving  above  it  just  room  sufficient  to  receive  a 
fagot.  The  fagots  are  made  of  furze,  heath,  brake,  fern,  &c.,  and  the  kiln  is  supplied  with 
these  until  its  arches  look  white,  and  the  fire  appears  at  the  top,  upon  which  the  fire  is 
slackened  for  an  hour,  and  the  kiln  allowed  gradually  to  cool.  This  heating  and  cooling  is 
repeated  until  the  bricks  are  thoroughly  burned,  which  is  generally  done  in  48  hours. 
One  of  these  kilns  will  hold  about  20,000  bricks. 

Clamps  are  also  in  common  use.  They  are  made  of  the  bricks  themselves,  and  generally 
of  an  oblong  form.  The  foundation  is  laid  with  place  brick,  or  the  driest  of  those  just 
made,  and  then  the  bricks  to  be  burnt  are  Intilt  up,  tier  upon  tier,  as  high  as  the  clamp  is 
meant  to  be,  with  two  or  three  inches  of  brocze  or  cinders  strewed  between  each  layer  of 
bricks,  and  the  whole  covered  with  a  thick  stratum  of  breeze.  The  fire  place  is  perpen- 
dicular, about  three  feet  high,  and  generally  placed  at  the  west  end ;  and  the  flues  are 
formed  by  gathering  or  arching  the  bricks  over,  so  as  to  leave  a  space  between  each  of  nearly 
a  brick  wide.  The  flues  run  straight  through  the  clamp,  and  are  filled  with  wood,  coals, 
and  breeze,  pressed  closely  together.  If  the  bricks  are  to  be  burnt  off  quickly,  wiiich  may 
be  done  in  20  or  30  days,  according  as  the  weather  may  suit,  the  flues  should  be  only  at 
about  six  feet  distance  ;  but  if  there  be  no  immediate  hurry,  they  may  be  placed  nine  feet 
asunder,  and  the  clamp  left  to  burn  off  slowly. 

The  following  remarks  by  Mr.  H.  Chamberlain,  on  the  drying  of  Ijricks,  have  an  especial 
value  from  the  great  experience  of  that  gentleman,  and  his  careful  observation  of  all  the 
conditions  upon  which  the  preparation  of  a  good  brick  depends  : — 


208 


BRICK. 


"  The  drying  of  bricks  ready  for  burniDg  is  a  matter  of  great  importance,  and  requii  t  ? 
more  attention  than  it  generally  receives.  From  hand-made  bricks  we  have  to  evaporut'.- 
some  25  per  cent,  of  water  bel'ore  it  is  safe  to  burn  them.  In  a  work  requiring  the  make 
of  20,000  bricks  per  day,  we  have  to  evaporate  more  than  20  tons  of  water  every  24  hour.'^. 
Hand-made  bricks  lose,  in  drying,  about  one-fourth  of  their  weight,  and  in  drying  and 
burning  about  one-third.  The  average  of  machine  bricks — those  made  of  the  stiff  plastic 
clay — do  not  lose  more  than  half  the  above  amount  from  evaporation,  and  arc,  therefore,  of 
much  greater  specific  gravity  than  hand-made  ones. 

"  The  artificial  drying  of  bricks  is  carried  on  throughout  the  year  uninterruptedly  in  sheds 
having  the  floor  heated  by  fires ;  but  this  can  only  be  effected  in  districts  where  coal  is 
cheap.  The  floors  of  these  sheds  are  a  series  of  tunnels  or  flues  running  through  the  shed 
longitudinally.  At  the  lower  end  is  a  pit,  in  which  are  the  furnaces;  the  fire  travels  up  the 
flues  under  the  floor  of  the  shed,  giving  off  its  heat  by  the  way,  and  the  smoke  escapes  at 
the  upper  end,  through  a  series  of  (generally  three  or  four)  smaller  chimneys  or  stacks.  The 
furnace  end  of  these  flues  would  naturally  be  much  more  highly  heated  than  the  upper  end 
near  the  chimneys.  To  remedy  this,  the  floor  is  constructed  of  a  greater  thickness  at  the 
fire  end,  and  gradually  diminishes  to  within  a  short  distance  of  the  top.  By  this  means, 
and  by  the  assistance  of  dampers  in  the  chimneys,  it  is  kept  at  nearly  an  equal  temperature 
throughout.  Bricks  that  will  bear  rapid  drying,  such  as  are  made  from  marly  clays  or  very 
loamy  or  siliceous  earths,  will  be  fit  for  the  kiln  in  from  12  to  24  hours.  Before  the  duty 
was  taken  ott'  bricks,  much  dishonesty  was  practised  by  unprincipled  makers,  where  this 
drying  could  be  carried  on  economically.  Strong  clays  cannot  be  dried  so  rapidly.  These 
sheds  are  generally  walled  round  with  loose  bricks,  stacked  in  between  each  post  or  pillar 
that  supports  the  roof.  The  vapor  given  oft'  from  the  wet  bricks,  rising  to  the  roof,  escapes. 
This  system  of  drying  is  greatly  in  advance  of  that  in  the  open  air,  for  it  produces  the  ware, 
as  made,  without  any  deterioration  from  bad  weather ;  but  the  expense  of  fuel  to  heat  these 
flues  has  restricted  its  use  to  the  neighborhood  of  collieries.  In  1845  attention  was  turned 
to  the  drying  of  bricks,  and  cxijcrimcnts  carried  cut  in  drying  the  ware  with  the  waste  lieat 
of  the  burning  kilns.  The  caloric,  after  having  passed  the  ware  in  burning,  was  carried  up 
a  flue  raised  above  the  floor  of  the  shed,  and  gave  oft' its  spent  heat  for  drying  the  ware. 
Although  this  kiln  was  most  useful  in  jjroving  that  the  waste  heat  of  a  burning  kiln  is  more 
than  sufficient  to  dry  ware  enough  to  fill  it  again,  it  was  abandoned  on  account  of  the  con- 
struction of  the  kiln  not  being  good. 

"  Another  system  of  drying  is  in  close  chambers,  by  means  of  steam,  hot  water,  or  by 
flues  heated  by  fire  under  the  chambers.  I  will,  therefore,  briefly  describe  the  steam 
chamber,  as  used  by  Mr.  Beart.  This  is  a  square  construction  or  series  of  tunnels  or  cham- 
bers, built  on  an  incline  of  any  desired  length  ;  and  at  some  convenient  spot  near  the  lower 
end,  is  fixed  a  large  steam  boiler,  at  a  lower  level  than  the  drying  chamber.  From  the 
boiler  the  main  steam  pipe  is  taken  along  the  bottom  or  lower  end  of  the  chamber,  and  from 
this  main,  at  right  angles,  run  branch  pipes  of  four  inches  diameter  up  the  chamber,  two 
feet  ajjart,  and  at  about  three  feet  from  the  top  or  arch.  From  there  being  so  close  and 
shallow  a  chamber  between  the  heating  surface  of  the  pipes  and  the  top,  and  so  large  an 
amount  of  heating  surface  in  the  pipes,  the  temperature  is  soon  considerably  raised.  At 
the  top  and  bottom  ends  are  shutters  or  lids,  which  open  for  the  admission  of  the  green 
ware  at  the  upper  end,  and  for  the  exit  of  the  dry  ware  at  the  lower  end  of  the  chamber. 
Over  the  steam  pipes  are  fixed  iron  rollers,  on  which  the  trays  of  bricks,  as  brought  from 
the  machine,  are  placed,  the  insertion  of  one  tray  forcing  the  tray  previously  put  in  further 
on,  assisted  in  its  descent  by  the  inclination  of  the  construction.  The  steam  being  raised  in 
the  boiler  flows  through  the  main  into  those  branch  pipes  in  the  chamber,  and  from  the 
large  amount  of  exposed  surface  becomes  condensed,  giving  off  its  latent  heat.  From  the 
incline  given  to  the  pipes  in  the  chamber,  and  from  the  main  pipe  also  having  a  fall 
towards  the  boiler,  the  whole  of  the  warm  water  from  the  condensed  steam  flows  to  the 
boiler  to  be  again  raised  to  steam,  sent  up  the  pipes,  and  condensed  intermittently.  The 
steam  entering  at  the  lower  end  of  the  chamber,  it  is,  of  course,  warmer  than  the  upper 
end.  Along  the  top  end  or  highest  part  of  the  chamber  is  a  series  of  chimneys  and  wind- 
guards,  through  which  the  damp  vapor  escapes.  The  bricks  from  the  machine  enter  at  this 
cooler  end  charged  with  warm  vapor,  and  as  the  make  proceeds  are  forced  down  the  cham- 
ber as  each  tray  is  put  in.  Thus,  those  which  were  first  inserted  reach  a  drier  and  warmer 
atmosphere,  and,  on  their  arrival  at  the  lower  end,  come  out  dry  bricks,  in  about  24  hours, 
with  the  strongest  clay.s.  In  some  cases  the  waste  steam  of  the  working  engine  is  sent 
through  these  pipes  and  condensed.  Bricks  will  dry  soundly  without  cracking,  &c.,  in  these 
close  chambers,  when  exposed  to  much  greater  heat  than  they  would  bear  on  the  open  flue 
first  described,  or  the  open  air,  from  the  circumstance  of  the  atmosphere,  although  very 
hot,  being  so  highly  charged  with  vapor.  In  i)ractice,  these  steam  chambers  have  proved 
many  principles,  but  they  are  not  likely  to  become  universal,  for  they  are  very  expensive 
in  erection  on  account  of  the  quantity  of  steam  pipes,  and  involve  constant  expense  in  fuel, 
and  require  attention  in  the  management  of  the  steam  boiler ;  but  their  greatest  defect  is 


BRICK. 


209 


the  want  of  a  current  of  hot  air  through  the  chamber  to  carry  off  the  excess  of  vapor  faster 
than  is  now  done.  The  attaining  a  high  degree  of  temperature  in  these  chambers  is  useless, 
unless  there  is  a  current  to  carry  off  the  vapor.  Why  should  this  piping  be  used,  or  steam 
at  all,  when  we  have  a  large  mass  of  heat  being  constantly  wasted,  night  and  day,  during 
the  time  the  kilns  are  burning  ?  and  after  the  process  of  burning  the  kiln  is  completed,  we 
have  pure  hot  air  flowing,  from  48  to  60  hours,  from  the  mass  of  cooling  bricks  in  the  kilns, 
free  from  carbon  or  any  impurities ;  this  could  be  directed  through  the  drying  chambers, 
entering  in  one  constant  flow  of  hot  dry  air,  and  escaping  in  warm  vapor.  The  waste  heat 
during  the  process  of  burning  can  be  taken  up  flues  under  the  chamber,  and  thereby  all  the 
heat  of  our  burning  kilns  may  be  economized,  and  a  great  outlay  saved  in  steam  pipes, 
boilers,  and  attention.  It  must  not  be  forgotten,  also,  that  so  large  an  atmospheric  con- 
denser as  the  steam  chamber  is  not  heated  without  a  considerable  expenditure  in  fuel.  This 
drying  by  steam  is  a  great  stride  in  advance  of  the  old  flued  shed,  but  practical  men  must 
see  the  immense  loss  incurred  constantly  from  this  source  of  the  spent  heat  of  the  burning 
kilns,  and  that  by  economizing  it,  an  immense  saving  will  be  effected  in  the  manufacture. 
The  kilns  are  constructed  as  near  the  lower  end  of  these  chambers  as  convenient." 

Mr.  Chamberlain  must  be  again  quoted  on  the  burning  of  bricks : — "  I  will  now  more 
fully  describe  a  principle  of  burning  which  I  have  had  in  practice  for  the  last  six  years,  and 
which  I  can  therefore  recommend  with  great  confidence.  The  great  object  in  brick-burning 
is  to  attain  a  sufficient  heat  to  thoroughly  burn  the  ware  with  ^s  small  a  consumption  of 
coal  as  possible  ;  and  with  nearly  an  equal  distribution  of  the  heat  over  all  parts,  so  that  the 
whole  of  the  ware,  being  subjected  to  the  same  temperature,  may  contract  equally  in  bulk, 
and  be  of  one  uniform  color  throughout.  The  advantage  is  also  gained  of  burning  in  much 
less  time  than  in  the  old  kilns,  which,  on  an  average,  took  a  week  ;  and  the  management  is 
so  simplified  that  any  man,  even  though  not  at  all  conversant  with  the  manufacture,  after 
he  has  seen  one  kiln  burnt,  will  be  able  to  manage  another ;  and  the  last,  though  not  least, 
advantage  is,  that  of  delivering  up  to  us  the  waste  heat  at  the  ground  level,  or  under  the 
floor  of  the  kiln,  to  be  used  in  drying  the  green  ware,  or  in  partially  burning  the  next  kiln. 

"  Hitherto  the  heat  has  been  applied  by  a  series  of  fire-places,  or  flues  and  openings 
round  the  kiln,  each  exposed  to  the  influence  of  the  atmosphere ;  and  in  boisterous  weather 
it  is  very  difficult  to  keep  the  heat  at  all  regular,  the  consequence  of  which  is  the  unequal 
burning  we  often  see.  The  improvements  sought  by  experimentalists  have  been  the  burn- 
ing the  goods  equally,  and,  at  the  same  time,  more  economically.  These  are  obtained  l)y 
the  patent  kilns,  as  improved  by  Mr.  Robert  Scrivener,  of  Shelton,  in  the  Staffordshire  Pot- 
teries. The  plan  is  both  simple  and  effective,  and  is  as  follows : — A  furnace  is  constructed 
in  the  centre  of  the  kiln,  mucli  below  the  floor  level,  and  so  built  that  the  heat  can  be  di- 
rected to  any  part  of  the  kiln  at  the  pleasure  of  the  fireman.  First,  the  heat  is  directed  up 
a  tube  in  the  centre  to  the  top  of  the  oven  or  kiln,  and,  as  there  is  no  escape  allowed  to 
take  place  there,  it  is  drawn  down  through  the  goods  by  the  aid  of  flues  in  connection  witli 
a  chimney.  Tims,  all  the  caloric  generated  in  the  furnace  is  made  use  of,  and,  being  cen- 
tral, is  equally  diffused  throughout  the  mass ;  but,  towards  the  bottom,  or  over  the  exit- 
flues,  the  ware  would  not  be  sufficiently  burnt  without  reversing  the  order  of  firing.  In 
order  to  meet  this  requirement,  there  is  a  series  of  flues  under  the  bottom,  upon  which  the 
goods  are  placed,  with  small  regulators  at  the  end  of  each ;  these  regulators,  when  drawn 
back,  allow  tlie  fire  to  pass  under  the  bottom,  and  to  rise  up  among  the  goods  which  are  not 
sufficiently  fired,  and  thus  the  burning  is  completed.  By  means  of  these  regulators  the  heat 
may  be  obtained  exactly  the  same  throughout ;  there  is,  therefore,  a  greater  degree  of  cer- 
tainty in  firing,  and  a  considerable  saving  of  fuel,  with  the  entire  consumption  of  the  smoke. 
From  the  fire  or  draught  being  under  command,  so  as  to  be  allowed  either  to  ascend  or 
descend  through  the  ware  during  the  time  of  burning  or  cooling,  the  waste  caloric  can  be 
economized  and  directed  through  the  adjoining  kiln  in  order  to  partially  burn  it,  or  be  used 
in  drying  off  the  raw  wares  on  flues  or  in  chambers.  I  have  found  the  saving  of  fuel  in 
these  kilns,  over  the  common  kiln,  50  per  cent.  ;  and  to  give  an  idea  of  the  facility  with 
which  they  can  be  worked,  it  is  common  for  my  men  to  fill  the  kiln,  burn,  cool,  and  dis- 
charge it  in  six  days." — Chamberlain. 

There  are  numerous  machines  in  use  for  the  manufacture  of  bricks.  For  the  manufac- 
ture of  perforated  bricks,  Mr.  Heart's  machine  is  the  most  generally  employed.  Mr.  Cham- 
berlain thus  describes  it : — "  The  most  imiversally  used  die  machine  which  lias  been  exten- 
sively worked  up  to  the  present  time  is  Mr.  Beart's  patent  for  jjcrforated  bricks.  Tiiis  gen- 
tleman, who  is  practically  acquainted  with  these  matters,  in  order  to  remedy  the  difliculties 
I  have  mentioned  in  expressing  a  mass  of  clay  through  a  large  aperture  or  die,  hung  a  series 
of  small  tongues  or  cores,  so  as  to  form  hollow  or  perforated  bricks.  By  this  means  the 
clay  was  forced  in  its  passage  through  the  die  into  the  corners,  having  the  greater  amount 
of  friction  now  in  the  centre.  Still,  the  bricks  came  out  rough  at  the  edge  with  many  clays, 
or  with  wliat  is  termed  a  jagged  edge.  The  water  die  was  afterwards  applied  to  this  ma- 
chine, and  tiie  perforated  bricks,  now  so  commonly  used  in  London,  are  the  result.  In  Mr. 
Beart's  machine,  which  is  a  pug-mill,  the  clay  is  taken  after  passing  through  the  rolling-mill, 
Vol.  III.— 14 


210 


BRICK. 


and,  being  fed  in  at  the  top,  is  worked  down  by  the  knives.  At  the  bottom  arc  two  horizon- 
tal elav-boxes,  in  which  a  phinger  works  backwards  and  forwards.  As  soon  as  it  has  reached 
the  extremity  of  its  stroke,  or  Ibrced  the  clay  of  one  box  through  the  die,  the  other  box  re- 
ceiving during  this  time  its  charge  of  clay  from  the  pug-mill,  the  plunger  returns  and  emp- 
ties this  box  of  clay  through  a  die  on  the  opposite  side  of  the  machine.  The  result  is,  that 
while  a  stream  of  clay  is  being  forced  out  on  one  side  of  the  machine,  the  clay  on  the  oppo- 
site side  is  stationary,  and  can,  therefore,  be  divided  into  a  scries  of  five  or  six  bricks  with 
the  greatest  correctness  by  hand.  Some  of  these  machines  have  both  boxes  on  one  side, 
and  the  plungers  worked  by  cranks.  This  machine  cannot  make  bricks  unless  the  clay  has 
previously  passed  through  rollers,  if  coarse ;  for  any  thing  at  all  rough,  as  stone  or  other 
iiard  substance,  would  hang  in  the  tongues  of  the  die.  But  the  clay  being  afterwards 
pugged  in  the  machine,  is  so  thoroughly  tempered  and  mixed,  that  the  bricks,  when  made, 
cannot  be  otherwise  than  good,  provided  they  are  sufiiciently  fired.  As  to  the  utility  of 
hollow  or  perforated  bricks,  that  is  a  matter  more  for  the  consideration  of  the  architect  or 
builder  than  for  the  brick-maker.  Perforated  bricks  arc  a  fifth  less  in  weight  than  solid 
ones,  which  is  a  matter  of  some  importance  in  tran.sit ;  but  it  takes  considerably  more  power 
to  force  the  clay  through  those  dies  than  for  solid  brick-making.  In  the  manufacture  of 
perforated  bricks,  there  is  also  a  royalty  or  patent  right  to  be  paid  to  Mr.  Beart." 


Mr.  Chamberlain's  own  machine  is  in  principle  as  follows  {fcj.  ^1a) : — The  clay  is  fed 
into  a  png-mill,  ])laced  horizontally,  which  works  and  amalgamates  it,  and  then  forces  it  off 
through  a  mouth-piece  or  die  of  about  05  square  inches,  or  about  half  an  inch  deeper,  and 
lialf  an  inch  longer  than  is  required  for  the  brick,  of  a  form  similar  to  a  brick  on  edge,  but 
with  corners  well  rounded  off,  each  corner  forming  a  quarter  of  a  3-inch  circle,  for  clay  will 
pas.s  smoothly  through  an  aperture  thus  formed,  but  not  through  a  keen  angle.  After  the 
clay  has  escaped  from  the  mill,  it  is  .seized  by  four  rollers,  covered  with  a  porous  fabric, 
(moleskin,)  driven  at  a  like  surface  sjieed  from  connection  with  the  pug-mill.  These  rollers 
arc  two  horizontal  and  two  vertical  ones,  having  a  space  of  45  inches  between  them  ;  they 
take  this  larger  stream  of  rough  clay,  and  press  or  roll  it  into  a  squared  block,  of  the  exact 
size  and  shape  of  a  brick  cdgcway.s,  with  beautiful  sharp  edges,  for  the  clay  has  no  friction, 
being  drawn  through  by  the  rollers  instead  of  forcing  itself  through,  and  is  delivered  in  one 
unbroken  stream.  The  rollers  in  this  machine  perform  the  functions  of  the  die  in  one  class 
of  machinery,  and  of  the  mould  in  the  other.  They  are,  in  fact,  a  die  with  rotating  sur- 
faces. By  hanging  a  series  of  mandrels  or  cores  between  these  rollers,  or  by  merely  chang- 
ing the  mouth-piece,  we  make  hollow  and  perforated  bricks,  without  any  alteration  in  the 
machine. 

Jlessrs.  Bradley  and  Craven,  of  Wakefield,  have  invented  a  very  ingenious  brick-making 
macliine : — 

It  consists  of  a  vertical  pug-mill  of  a  peculiar  form,  and  greatlv  improved  construction, 
into  the  upper  part  of  which  the  clay  is  fed.  In  this  part  of  the  "apparatus  the  clav  under- 
goes a  most  perfect  tempering  and  mixing,  and,  on  reaching  the  bottom  of  the  m'ill,  thor- 
oughly amalgamated,  is  forcibly  pressed  into  the  moulds  of  the  form  and  size  of  brick  re- 
quired, which  are  arranged  in  the  form  of  a  circular  revolving  table. 


BRICK. 


211 


As  this  table  revolves,  the  piston-rods  of  the  moulds  ascend  an  incline  plane,  and  grad- 
ually lift  the  bricks  out  of  the  moulds,  whence  they  are  taken  from  the  machine  by  a  boy, 
and  placed  on  an  endless  band,  which  carries  the  bricks  direct  to  the  waller,  thus  effecting 
the  saving  of  the  floor  room. 

The  speed  of  the  several  parts  of  the  machine  is  so  judiciously  arranged,  that  the  opera- 
tions of  pugging,  moulding,  and  delivering  proceed  simultaneously  in  due  order,  the  whole 
being  easily  driven  by  a  steam  engine  of  about  six-horse  power,  which,  at  the  ordinary  rate 
of  working,  will  make  12,000  bricks  per  day;  or,  with  eight-horse  power,  from  15,000  to 
18,000. 

In  consequence  of  the  perfect  amalgamation  of  the  clay,  and  the  great  pressure  to  which 
it  is  subjected  in  the  moulds,  the  bricks  produced  by  this  machine  are  perfect ;  and  from 
the  stiffness  of  the  clay  used,  less  water  has  to  be  evaporated  in  the  drying,  thus  saving  one- 
half  the  time  required  for  hand-made  bricks,  and  avoiding  the  risk  of  loss  from  bad  weather. 

A  very  ingenious  and  simple  brick-making  machine  was  constructed  and  patented  by 
Mr.  Roberts,  of  Falmouth,  and  it  has  been  extensively  worked  by  him  in  the  parish  of  Mylor. 

Fig.  89  shows  a  plan  of  machinery  combined,  according  to  Mr.  Roberts's  invention,  and 
■fif).  9i)  shows  a  side  elevation,  partly  in  section,  a  is  a  circular  track,  on  which  are  fixed 
series  of  moulds,  6,  at  intervals,  the  form  of  moulds  being  according  to  the  shape  of  bricks 
or  tiles  to  be  made.  Each  set  of  moulds  is  provided  with  movable  bottoms,  (one  for  each 
mould,)  which  are  connected  to  the  bar,  c,  so  that  they  may  be  all  simultaneously  lifted  by 
the  lever,  d. 

ln,fi(j-  90,  one  set  of  the  moulds  and  apparatus  used  therewith  is  shown,  and  the  several 
sets  of  moulds  (the  positions  of  which  are  in  the  drawing,  ^^^.  89)  are  similarly  provided, 
e  is  a  roller,  which  is  moved  round  on  the  track,  a,  by  means  of  the  frame,/,  which  receives 
motion  from  a  steam-engine  or  other  power,  by  means  of  the  shaft,  c/,  the  cog-wheel,  /',  and 
circular-toothed  rack  fixed  on  the  frame,/.  The  clay,  or  brick  earth,  is  filled  into  the 
moulds,  and  the  roller,  c,  presses  the  same  into  the  moulds  as  it  rolls  over  them  ;  i  is  a 
scraper  which,  following  the  roller,  e,  removes  any  excess  of  clay  or  brick  earth  from  the 
moulds  ;  and  J  is  a  smaller  roller,  which  acts  as  a  balance,  to  prevent  the  cutter  from  rising; 
k  is  a  pressing  plate  attached  to  the  bar,  r,  and  is  raised  at  the  .«;ame  time  by  the  lever,  d. 
T!ie  roller,  e,  in  its  further  progress,  passes  over  and  presses  down  the  plate,  /■,  which  com- 
pletes the  pressure ;  c  then  passes  on  and  presses  down  the  lever,  rf,  by  which  all  the  mov- 
able bottoms  of  the  moulds  will  be  raised  with  the  bricks  or  tiles  thereon.  The  whole  of 
the  pistons  and  bar,  c,  are  kept  up  by  the  stop,  /,  which  works  by  a  spring,  and  is  removed 
by  the  treadle,  in,  as  soon  as  the  bricks  or  tiles  are  taken  away  ;  n  are  small  rollers,  fixed 
to  the  frame,  o,  to  which  the  cutter  or  scraper  is  attached. 


212 


For  the  analyses  of  the  clays  of  which  these  and  others  are  constructed,  see  Clay. 

Stone  Bricka. — These  are  manufactured  at  Neath,  in  Glamorganshire,  and  are  rery 
much  used  in  the  construction  of  copper  furnaces  at  Swansea. 

The  materials  of  which  the  bricks  are  made  are  brought  from  a  quarry  in  the  neighbor- 
hood. They  are  very  coarse,  being  subjected  to  a  very  rude  crushing  operation  under  an 
edge  stone,  and,  from  the  size  of  the  pieces,  it  is  impossible  to  mould  by  hand.  There  are 
three  qualities,  which  arc  mixed  together  with  a  little  water,  so  as  to"  give  the  mass  co- 
herence, and  in  this  .state  it  is  compressed  by  the  machine  into  a  mould.  The  brick  which 
results  is  treated  in  the  ordinary  way,  but  it  resists  a  much  greater  heat  than  the  Stour- 
bridge clay  brick,  expands  more  by  heat,  and  does  not  contract  to  its  original  dimensions. 
The  composition  of  the  three  materials  is  as  follows : 


From  Pondrevn. 
Silica      -         -         -         -         .        V     94-05    ". 

Alumina,  with  a  trace  of  ox.  iron           4-.5,5     . 
Lime  and  magnesia 


From  Dinns. 
100-  91-95 
traces  8"05 
traces  traces 


98-60  100-   100-00 

— Dr.  Richardson  :  Knapp's  Technology. 
In  immediate  connection  with  this  subject,  it  appears  that  the  following  machine  for 
raising  bricks,  mortar,  &c.,  by  M.   Pierre  Journet,  described  to  the  London  Institution  of 
Civil  Engineers,  merits  attention.     It  is  a  machine  for  raising  bricks  and  materials  to  pro- 


20 

45 

30 

30 

40 

22 

60 

18 

60 

15 

BRONZE.  213 

gresive  heights  in  the  building  of  chimneys  and  other  works.  A  strong  frame  on  the 
ground  contained  the  winch  wheel,  and  on  the  second  motion  a  notched  wheel ;  on  the 
scaffold  frame  above  is  a  similar  notched  wheel,  and  round  these  two  wheels  an  endless  chain 
travels,  made  of  flat  links  and  cross  pins,  which  are  held  by  the  notches  in  the  wheels.  The 
buckets  for  mortar,  and  hods  for  bricks,  are  hooked  upon  these  transverse  pins,  and  are 
raised,  by  the  winch  motion  below,  to  the  landing  above  ;  the  bricks  are  removed  by  labor- 
ers, and  empty  buckets  and  hods  hung  to  the  descending  chain,  to  be  detached  and  filled 
below. 

It  appeared  that  a  working  rate  of  1 5  feet  in  a  minute  for  the  chain  to  travel  was  a  con- 
venient rate  for  the  men.     One  man  turning  the  winch  will  raise — 

10  feet  high  90  bricks  per  minute,  or  =  5400  bricks  per  hour. 
"  "  =  2700         "         " 

"  "  =  1800         "         " 

«  _   135Q  u  u 

"  "  =  1080  "         " 

"  "  =     900  "         " 

As  the  work  increases,  the  scaffold  is  elevated,  and  the  chain  lengthened,  adding  more  hods. 

The  great  advantages  are,  that  the  men  are  relieved  from  the  labor  of  climbing  ladders 
and  risk  of  accidents,  that  the  building  is  carried  on  quicker,  and  therefore  at  less  cost. 
The  plan  was  adopted  with  success  at  the  large  buildings  at  Albert  Gate,  Hyde  Park,  and  at 
the  new  Houses  of  Parliament. 

Steam  power,  of  course,  can  be  employed  ;  and  a  great  practical  advantage  arises  from 
not  encumbering  the  building  with  the  weight  of  ladders,  and  materials  collected  on  the 
scaffolding. 

BROMINE.  (Br.  Atomic  weight,  80.  Density  in  liquid  state,  2-97.  Density  of  vapor 
by  experiment,  5 "39 ;  calculation  on  supposition  of  the  density  of  hydrogen  being 
0-0692, 5-536.)  One  of  the  most  active  of  the  elements.  It  was  discovered  in  1826,  by 
Balard,  of  Montpellier,  in  the  bittern  produced  from  the  water  of  the  Mediterranean.  Bro- 
mine is  a  very  interesting  substance,  and  its  discovery  has  had  great  influence  on  the  pro- 
gress of  theoretical  and  applied  chemistry.  It  is  the  only  element,  save  me.rcury,  which 
exists  in  the  fluid  state  at  ordinary  temperatures.  It  is  found  not  only  in  sea  water,  but  in 
numerous  saline  springs.  It  also  exists  in  combination  with  silver  and  chlorine  in  some 
Mexican  and  Chilian  minerals. 

Preparation  1.  From  bittern. — Chlorine  gas  is  passed  in  for  some  time ;  this  has  the 
effect  of  combining  with  the  metallic  base  of  the  bromide  present,  the  bromine  being,  in 
consequence,  liberated.  "When  the  bittern  no  longer  increases  in  color,  the  operation  is 
suspended,  or  chloride  of  bromine  would  be  formed,  and  spoil  the  operation.  The  colored 
fluid  is  placed  in  a  large  globe,  with  a  neck  having  a  glass  stopcock  below  like  a  tap  funnel, 
the  upper  aperture  being  closed  with  a  stopper.  ■  Ether  is  then  added,  the  stopper  replaced, 
and  the  whole  well  agitated.  After  a  short  repose,  the  ether  rises  to  the  surface  retaining 
the  bromine  in  solution.  The  stopper  being  removed  to  permit  the  entrance  of  air,  the 
stopcock  is  opened,  and  the  aqueous  fluid  is  permitted  to  run  out.  As  soon  as  the  highly 
colored  etheral  solution  arrives  at  the  aperture  in  the  stopcock,  the  latter  is  shut ;  a  quan- 
tity of  solution  of  potash  is  then  poured,  by  the  upper  aperture,  into  the  globe,  and  the 
stopper  is  replaced.  The  whole  is  now  to  be  agitated,  by  which  means  the  bromine  com- 
bines with  the  potash,  forming  a  mixture  of  bromate  of  potash  and  bromide  of  potassium. 
The  stopcock  is  again  opened,  and  the  aqueous  fluid  received  into  an  evaporating  vessel, 
boiled  to  dryness,  and  ignited.  By  this  means  the  bromate  of  potash  is  all  converted  into 
bromide  of  potassium.  The  bromine  may  be  procured  from  the  bromide  of  potassium  by 
distillation  with  peroxide  of  manganese  and  sulphuric  acid.  In  this  operation  one  equiv- 
alent of  bromide,  two  equivalents  of  sulphuric  acid,  and  one  of  pcrpxide  of  manganese, 
yield  one  equivalent  of  sulphate  of  manganese,  one  of  sulphate  of  potash,  and  one  of  bro- 
mine _;  or,  in  symbols,  KBr  -f  2S0=  -f  MnO^  =  KO,  SO^  -f  MnO,  SO^  -j-  ^r.  The  reac- 
tion, in  fact,  takes  place  in  two  stages,  but  the  ultimate  result  is  as  represented  in  the 
equation. 

Preparation  2. — In  some  saline  springs  where  bromine  is  present,  accompanied  by  con- 
siderable quantities  of  salts  of  lime,  &c.,  the  brine  may  be  evaporated  to  one-fourth,  and, 
after  repose,  decanted  or  strained  from  the  deposit.  The  mother  liqiiid  is  to  have  sulphuric 
acid  added,  in  order  to  precipitate  most  of  tlie  lime.  The  filtered  fluid  is  then  evaporated 
to  dryness,  redissolved  in  water,  and  filtered  ;  by  this  means  more  sulphate  of  lime  is  got 
rid  of.     The  fluid  is  then  distilled  with  peroxide  of  manganese  and  hydrochloric  acid. 

The  only  well-developed  oxide  of  bromine  is  bromic  acid,  BrO^  Solutions  of  bromine 
in  water  may  have  their  strength  determined,  even  in  presence  of  hydrochloric  or  liydro- 
bromic  acids,  by  means  of  a  solution  of  turpentine  in  alcohol.  One  quarter  of  an  equivalent 
of  turpentine  (34  parts)  decolorizes  80  parts  or  1  equivalent  of  bromine. — C.  G.  W. 

BRONZE.  {Bronze,  Fr. ;  Bronze,  Germ.)  A  compound  metal  consisting  of  copper 
and  tin,  to  which  sometimes  a  little  zinc  and  lead  are  added.     There  is  some  confusion 


214  BRONZE. 

amongst  continental  writers  about  this  alloy  ;  they  translate  their  bronze  into  the  English 
brass. 

Sec,  for  an  example  of  this,  "  Dictionnaire  des  Arts  et  Manufactm-es."  This  has  arisen 
from  the  carelessness  of  our  own  writers.  Dr.  Watson,  "  Chemical  Essays,"  remarks  :  '*  It 
lias  been  said  that  Queen  Elizabeth  left  more  brass  ordnance  at  her  death  than  she  found 
iron  on  her  accession  to  the  throne.  This  must  not  be  understood  as  if  gun  metal  was  made 
in  her  time  of  brass,  for  the  term  brass  was  sometimes  used  to  denote  copper ;  and  some- 
times a  composition  of  iron,  copper,  and  calamine  was  called  brass ;  and  we,  at  this  day, 
commonly  speak  of  brass  cannon,  though  brass  does  not  enter  into  the  composition  used 
for  casting  cannon." 

Bronze  is  an  alloy  of  copper  and  tin. 
Brass  is  an  alloy  of  copper  and  zinc. 

In  niauy  instances,  we  have  zinc,  lead,  &c.,  entering  into  the  composition  of  alloys  of 
copper  and  tin.  However  this  may  be,  the  alloy  is  called  a  bronze,  if  tin  and  copper  are 
the  chief  constituents. 

This  alloy  is  much  harder  than  copper,  and  was  employed  by  the  ancients  to  make 
swords,  hatchets,  &c.,  before  the  method  of  working  iron  was  generally  understood.  The 
art  of  casting  bronze  statues  may  be  traced  to  the  most  remote  antiquity,  but  it  was  first 
brought  to  a  certain  degree  of  refinement  by  Theodoros  and  Roecus  of  Samos,  about  VOO 
years  before  the  Christian  era,  to  whom  the  invention  of  modelling  is  ascribed  by  Pliny. 
The  ancients  were  well  aware  that  by  alloying  copper  with  tin,  a  more  fusible  metal  was 
obtained,  that  the  process  of  casting  was  therefore  rendered  easier,  and  that  the  statue  was 
harder  and  more  durable.  It  was  during  the  reign  of  Alexander  that  bronze  statuary  re- 
ceived its  greatest  extension,  when  the  celebrated  artist  Lysippus  succeeded,  by  new  pro- 
cesses of  moulding  and  melting,  in  multiplying  groups  of  statues  to  such  a  degree  that 
Pliny  called  them  the  mob  of  Alexander.  Soon  afterwards  enormous  bronze  colossuses 
were  made,  to  the  height  of  towers,  of  which  the  isle  of  Rhodes  possessed  no  less  than  one 
hundred.  The  Roman  consul  Mutianus  found  3,000  bronze  statues  at  Athens,  3,000  at 
Rhodes,  as  many  at  Olympia  and  at  Delphi,  although  a  great  number  had  been  previously 
carried  off  from  the  last  town. 

From  the  analyses  of  Mr.  J.  A.  Phillips,  we  learn  that  most  of  the  ancient  coins  were 
bronzes,  the  quantity  of  tin  relatively  to  the  copper  varying  slightly.  The  proportions  of 
copi)er  and  tin  in  many  of  those  coins  are  given  below,  the  other  ingredients  being 
omitted  : — 

Copper.  Tin. 

A  coin  of  Alexander  the  Great,  335  B.  c.      -         -      86-72     -         -     13-14 
"         PhillipusV.  -    200  B.  c.      -         -      8.5-15     -         -     11-10 

"         Athens 88-41     -         -       9-95 

"         Ptolemy  IX.    -         -     70  b.  c.      -         -      84-21     -         -     15-59 
"         Pompey  -         -     53  b.  c.      -         -      74-11     -         -       8-56 

"         the  Atilia  family      -     45  b.  c.      -         -      68-72     -         -       4*77 
"         Augustusand  Agrippa,  30  B,  c.      -         -      78-58     -         -     12-91 

The  arms  and  cutting  instruments  of  the  ancients  were  composed  of  similar  bronzes, 
as  the  following  proportions,  also  selected  from  Mr.  J.  A.  Phillips's  analyses,  will  show  : — 

Roman  sword  blade,  found  in  the  Thames    - 

"  "  "  Ireland 

Celtic  "  "  Ireland 

Laj-ard  brought  from  Assyi'ia  a  considerable  variety  of  bronze  articles,  many  of  them 
objects  of  ornament,  Init  many  evidently  intended  for  use.  Amongst  others  was  a  bronze 
foot,  which  was  constructed  for  the  purpose  of  support  of  some  kind.  This  was  submitted 
to  the  examination  of  Dr.  Percy.  It  was  then  found  that  the  bronze  had  been  cast  round  a 
support  of  iron.  By  this  means  the  appearance  of  considerable  lightness  was  attained,  while 
great  strength  was  insured.  This  discovery  proves,  in  a  very  satisfactory  manner,  that  the 
metallurgists  of  Assyria  were  perfectly  conversant  with  the  use  of  iron,  and  that  they  cm- 
ployed  it  for  the  purpose  of  imparting  strength  to  the  less  tenaceons  metals  which  they  cm- 
ployed  in  their  art  manufactures.  This  bronze,  as  analysed  in  the  Metallurgical  Laboratory 
of  the  Museum  of  Practical  Geolog)',  consists  of  copper  88-37,  tin  11-33. 

Examination  has  shown  that  all  the  bronze  weapons  of  the  Greeks  and  Romans  were  not 
only  of  the  true  composition  for  ensuring  the  greatest  density  in  the  alloy  itself,  but  that 
these,  by  a  process  of  hammering  the  cutting  edges,  were  brought  up  to  the  greatest  degree 
of  hardness  and  tenacity. 

Before  1542  "brass  ordnance"  {bronze)  was  foimded  by  foreigners.  Stow  says  that 
John  Owen  began  to  found  brass  ordnance,  and  that  he  was  the  first  Englishman  who  ever 
made  that  kind  of  artillery  in  England. 

Bell  founding  followed.     Bell  metal  and  other  broken  metal  were  allowed  to  be  ex- 


Copper. 

Tin. 

85-70     - 

-     10-02 

91-39     - 

-       8-38 

90-23     - 

-       7-50 

BEONZING.  215 

ported  hitherto  ;  but  it  being  discovered  that  it  was  apphed  to  found  guns  abroad  "  brass 
copper,  latten,  bell  metal,  pan  metal,  gun  metal,  and  shrolf  metal  are  prohibited  to  be  ex* 
ported." 

Bronze  has  almost  always  been  used  for  casting  statues,  basso  relievos,  and  works  which 
were  to  be  exposed  to  atmospheric  influences.  lu  forming  such  statues,  the  alloy  should  be 
capable  of  flowing  readily  into  all  the  parts  of  the  mould,  however  minute;  it  should  be 
hard,  in  order  to  resist  accidental  blows,  be  proof  against  the  influence  of  the  weather  and 
be  of  such  a  nature  as  to  acquire  that  greenish  oxidized  coat  upon  the  surface  which 'is  so 
much  admired  in  the  antique  bronzes,  called  patina  antiqua.  The  chemical  'composition 
of  the  bronze  alloy  is  a  matter,  therefore,  of  the  first  moment.  The  brothers  Keller  cele- 
brated founders  in  the  time  of  Louis  XIV.,  whose  chefs-d'oeuvre  are  well  known  directed' 
their  attention  towards  this  point,  to  which  too  little  importance  is  attached  at  the  present 
day.  The  statue  of  Desaix,  in  the  Place  Dauphine,  and  the  column  in  the  Place  Veudome 
are  noted  specimens  of  most  defective  workmanship  from  mismanagement  of  the  alloys  of 
which  they  are  composed.  On  analyzing  separately  specimens  taken  from  the  bass-reliefs 
ot  the  pedestal  of  this  column,  from  the  shaft,  and  from  the  capital,  it  was  found  that  the 
farst  contained  only  6  per  cent,  of  tin,  and  94  of  copper,  the  second  much  less,  and  the  third 
only  0-21.  It  was  therefore  obvious  that  the  founder,  unskilful  in  the  melting  of  bronze 
had  gone  on  progressively  refining  his  alloy,  by  the  oxidizement  of  the  tin,  till  he  had  ex- 
hausted the  copper,  and  that  he  had  then  worked  up  the  refuse  scoriaj  in  the  upper  part  of 
the  column      The  cannon  which  the  Government  furnished  him  for  casting  the  monument 

COllSlStGCl  01  I~^ 

^PPP^"* 89-360 

1^'^, 10-040 

^5               0-102 

Silver,  zinc,  iron,  and  loss 0-498 


100-000 
_    For  the  following  table  we  are  indebted  to  Mr.  Robert  Mallet,  C.  E.,  whose  investiga- 
tions in  this  direction  have  been  most  extensive,  and  as  accurate  as  they  are  extensive  ■— 


Chemical 
Constitution. 


Compoaition 
by  Weight 
per  cent. 


Cu  +  Sn 
lOCix  +  Sn 
9  0u+Sn 
8Cu+Sn 

TCu+Sn 

6Cu+Sn 
5Cu+Sn 
4Cii  +  Sn 
3 Cu+Sn 
2Cu+Sa 
Cu  +  Sn 
Cu+2Sn 

Cu+3Sn 
Cu+4Sn 

Cu+5Sn 


100-()0+         0 

84-29+  15-71 

82-81+  17-19i343-3  8-4G2 

81-10+  18-90  311-7  8-459 


31-6  S0G7 
374-9  8-561 


78-97+  21-03 


76-29  + 
72-80  + 
68-21  + 
61-69  + 
51-75  + 
34-92  + 
21  •15  + 

1.5-17  + 

11-82  + 
9-68  + 


23-71 
27-20 
81-79 
38-31 
48-25 


280-1  8-728 

I 
243-5  8-750 
216-9  8-5T5 
185-3  8-400 
153-7  8-539 
1'221  8-416 
65-08!  90-5  8-056 
78-85  149-4  7  387 

I  I 

84-83  208-3  7-447 
88'18;207-2  7-472 
90-32:326-1  7-442 


+  3n        O-OO  +  lOO-Oo!  589  7-291    f    White,  7  . 


Color  of  Fracture. 


Tile  red  - 
Reddish  yellow,  1 
Reddish  yellow,  2 
Yellowish  red,    " 

Yellowish  red,    1 

Bluish  rod,  1 
Bluish  red,  2 
Ash  gray    - 
Dark  pray  - 
Grayi.sh  -white,  1 
Whiter  still,      2 
Ditto  3 


Ditto 
Ditto 
Ditto 


2-5!    7 


Commercial  Titles, 

characteristic  Propertiea 

in  working,  &c. 


Copper. 

Gun  metal,  &c. 

Ditto. 
Gun  metal,  tempers 

best. 
Hard   mill   brasses, 

l-e. 
Brittle.t 
Brittle.t 
Crumbles.t 
Crumblcs.-f- 
Brittle.t 

Small  bells,  brittle.! 
Ditto     brittle.t 
Speculum : — 

Metal  of  authors. 

Fileii,  tough. 

Files,     soft     and 
tough. 
Tin. 


In  \S6(iyfe  imported,  of  Bronze,  works  of  art,  21  cwts.  ;  and  of  manufactures  of  bronze, 
or  ot  metal  bronzed  or  lacquered,  3,492  cwts. 

BRONZING.  The  process  for  giving  to  metals,  plaster,  wood,  or  any  other  body,  a 
bronze-hke  surface.  >  i  ,  ,  j  j,  . 

Various  processes  have  been  adopted  for  producing  this  effect. 

When  brass  castings  are  to  be  bronzed,  it  is  essential,  in  the  first  place,  that  they  should 
be  tlioroughly  cleansed  from  grease,  and  brightened  either  with  the  file  or  emery-paper  or 
by  boding  in  a  strong  lye  and  then  scouring  witii  fine  sand  and  water.  "  ' 

Vinegar  alone  is  sometimes  employed  to  produce  the  green  bronze  color ;  sometimes 
dilute  nitric  acid,  and  often  the  muriate  of  ammonia,  {sal  amnwniac.)     This  latter  salt  and 

^^:^^^^^SVc:'^^'^^2^''    PO,fln;  crystalline;   c,  conchoidal;  v,  vitreous;  v  c, 
t  All  these  alloys  are  found  occasionally  in  bells  and  specula  with  mixtures  of  Zn  and  Pb. 


216 


BEONZE  POWDEES, 


vincar  are  frequently  combined,  and  often  a  little  common  table  salt  is  added  to  the  bronz- 
ing fluid. 

The  best  and  most  rapid  bronzing  liquid,  which  may  be  applied  to  copper,  brass,  iron, 
or  to  new  bronze,  with  equal  advantage,  is  a  solution  of  the  chloride  of  platinum  {nilro- 
nntriate  of  platinum)  called  chemical  bronze ;  but  it  is  expensive.  With  the  chloride  of 
platinum,  almost  any  color  can  be  produced,  according  to  the  degree  of  dilution,  and  the 
number  of  applications. 

Some  beautiful  effects  are  produced  upon  bronze,  and  also  upon  iron  castings,  by  treat- 
in"  them  with  dilute  acids.  The  action  here  is  scarcely  to  be  described  as  bronzing  ;  it  is, 
in  fact,  merely  developing  the  true  color  of  the  metal  or  alloy. 

With  the  view  of  rendering  the  action  of  the  bronzing  liquid  as  uniform  as  possible, 
small  articles  are  dipped ;  for  larger  articles,  the  bronzing  liquid  is  dabbed  on  plentifully 
with  a  linen  rag.  The  dabbing  process  is  to  prevent  the  occurrence  of  streaks,  which  might 
arise  if  the  liquid  was  applied  in  straight  strokes.  When  properly  bronzed  and  washed,  the 
work  is  usualy  black-leaded,  to  give  it  a  polished  appearance. 

BRONZE  POWDERS  have  been  much  used  of  late  in  the  decorative  painting  of  houses, 
&c.  They  are  prepared  of  every  shade,  from  that  of  bright  gold  to  orange,  dark  copper, 
emerald  green,  &c.  Pale  gold  is  produced  from  an  alloy  of  13^  of  copper,  and  2f  of  zinc  ; 
crimson  metallic  lustre — from  copper :  ditto,  paler,  copper  and  a  very  little  zinc ;  green 
bronze,  with  a  proportion  of  verdigris ;  another  fine  orange  by  14^  copper  and  If  zinc ; 
another  ditto,  13f  copper  and  2^  zinc  :  a  beautiful  pale  gold  from  an  alloy  of  the  two  metals 
in  atomic  proportions. 

The  alloy  is  laminated  into  very  fine  leaves  with  careful  annealing,  and  these  are  levi- 
gated into  impalpable  powders  along  with  a  film  of  fine  oil  to  prevent  oxidizement,  and  to 
favor  the  levigation. 

On  the  subject  of  bronze  powders  and  metallic  leaves,  Mr.  Brandeis  furnished  to  the 
New  York  Exhibition  an  account  of  his  articles  of  manufacture  : — 

Bronzes,  or,  more  correctly,  metallic  powders  resembling  (/old  dicsf,  were  invented,  ac- 
cording to  my  researches,  in  1648,  by  a  monk,  at  Furth,  in  Bavaria,  named  Theophrastus 
Allis  Bombergensis.  He  took  the  scraps  or  cuttings  of  the  metallic  leaves  then  known  as 
"  Dutch  leaf,"  and  ground  them  with  honey.  This  roughly  made  bronze  powder  was  used 
for  ornamenting  parchments,  capital  letters  in  Bibles,  choral  books,  &c. 

As  the  consumption  of  metallic  leaf  increased,  and  the  properties  of  alloys  became  bet- 
ter known,  leaves  of  different  colors  were  produced,  and  from  the  scraps  a  variety  of  pow- 
ders or  bronzes. 

At  Furth,  bronze  powders  are  largely  made  for  Europe,  and  with  little  change  or  im- 
provement.    There  are  four  sorts  of  Dutch  leaf : 

Common  leaf,  soft,  and  of  a  reddish  cast,  composed  of  25  or  30  per  cent,  of  zinc  to  75 
or  70  per  cent,  of  copper. 

French  leaf  contains  more  zinc,  is  harder,  less  ductile,  and  has  a  purer'  yellow  color. 

Florence  leaf  has  a  larger  proportion  of  zinc,  and  is  of  a  greenish  gold  color ;  and 
lastly — 

Wliite  leaf  composed  of  tin.  The  more  zinc  these  alloys  contain,  the  harder,  the  more 
brittle,  and  more  difficult  are  they  to  work  into  perfect  leaves.  The  manner  of  beating  is 
similar  to  the  mode  for  producing  gold  leaves. 

The  scraps,  cuttings,  and  fragments  of  these  leaves  are  the  materials  for  the  German 
bronze  powders.  First  brushed  through  a  sieve  and  ground  with  gum  water  on  marble 
slabs  for  six  hours,  the  gum  washed  out,  the  powders  sorted,  dried,  and  a  coating  of  grease 
given  to  make  them  appeaj"  more  brilliant,  and  to  protect  them  from  oxidation.  Varieties 
of  color,  such  as  orange,  &c.,  are  produced  by  a  film  of  suboxide  upon  the  surface  of  the' 
particles.  The  price  of  bronze  powders  depends  upon  the  demand,  and  the  supply  of  the 
waste  material  of  the  metal  leaves,  and  prices  change  accordingly. 

Messrs.  Brandeis  patent  their  process,  and  in  place  of  being  dependent  upon  uncertain 
supplies  of  metal  and  unknown  composition,  they  take  the  metals  at  once  in  a  state  of  pu- 
rity, (say  copper  by  voltaic  precipitation  :)  it  is  alloyed  with  zinc,  cast  into  ingots,  rolled  into 
ribands,  cut,  annealed,  and  rolled  until  the  metal  is  thin  and  leaf-like  ;  then  it  is  taken  to  a 
steam-mill,  and  ground.  The  bronze  powder  is  washed  out  and  dried,  then  introduced  into 
an  air-tight  room,  with  an  arrangement  of  boxes ;  the  air  of  the  chamber  is  set  in  violent 
motion  by  bellows,  and  the  powder  diffused  throughout ;  the  bronze  powders  are  deposited, 
the  finest  in  the  upper  boxes,  and  the  coarser  powders  below.  When  settled,  mineral  var- 
nish is  introduced  ;  tlie  boxes,  fitted  with  tight  lids,  are  made  to  revolve,  and  the  particles 
are  thus  rapidly  coated,  and  the  highest  metallic  brilliancy  imparted.  Different  shades  of 
color,  pink,  crimson,  &e.,  are  produced  by  submitting  the  powder  to  heat  and  oxidation 
before  the  rapid  revolutions  of  the  varnishing  boxes. 

The  quantity  thus  produced  by  orre  firm,  with  three  steam-engines  at  work,  enables  the 
finished  bronze  powders  to  be  produced  at  a  rate  about  equal  to  the  price  the  German 
manufacturer  has  to  pay  for  his  materials — the  cuttings  and  scraps  of  leaves.     Hence,  for 


BEOWN  lEON  ORE. 


217 


the  purposes  of  trade  and  art,  a  large  exportation  of  bronze  powders  takes  place  from 
America  to  Europe,  South  America,  and  China. 

The  bronze  powders  are  largely  used  in  japanning,  bronzing  tin  and  iron  goods,  orna- 
mental woriis  of  paper,  wood,  oil-cloth,  leather,  &c.  ;  while  sign-boards  and  the  decoration 
of  public  buildings  have  effective  metallic  brilliant  surfaces  of  beauty  and  durability.  lu 
fact,  for  ornamental  decorations,  the  demand  steadily  increases. 

In  Ilolland  and  Germany  the  subject  has  been  examined,  with  the  view  of  ascertaining 
the  effect  of  chemical  composition. 

De  Heer  E.  R.  Konig  has  lately  given  a  table  of  the  analyses  of  the  best  European  sam- 
ples of  bronze  powders  and  leaves,  (  Volkujlight :) — 


Copper. 

Zinc. 

Iron. 

Tin. 

Per  cent. 

Per  cent. 

Per  cent. 

Per  cent. 

1.  Light  yellow           -         .         .         .         . 

82-38 

1C)-G9 

0-16 

0 

2.  Gold  yellow 

84-50 

15-30 

0-07 

0 

3.  Messing  yellow,  or  brass  copper  red-yel- 

low color 

90- 

9-Gl 

0-20 

0 

4.  Copper  bronze  orange   -         -         -         . 

98-93 

0-Y3 

0-08 

0 

5.  Copper  red,  high  shade  of  purple  color 

99-90 

0-00 

trace. 

0 

6.  Purple  violet 

98-22 

0-5 

0-30 

trace. 

7.  Light  green 

84-32 

15-02 

0-03 

trace. 

8.  Tin  white  or  leaden  gray 

0-00 

2-39 

0-56 

97-40 

Our  importations  in  1856  of  Bronze  Powders  were  valued  at  £4,737,  according  to  the 
Custom  House  computation. 

BROWX  COAL  is  of  a  brownish-black  color,  and  presents,  in  some  cases,  the  texture 
of  wood,  when  it  is  called  Lignite  ;  but,  in  some  varieties,  all  organic  structure  has  disap- 
peared, and  it  is  then  called  pitch  coal,  from  its  strong  resemblance  to  true  coal. 

The  beds  of  brown  coal  are  generally  of  small  extent,  and  are  of  hater  date  than  the  true 
carboniferous  strata,  belonging  to  the  Tertiary  period. 

Brown  coal  is  worked  in  Saxony  and  in  countries  where  there  is  an  absence  of  true  car- 
boniferous deposits.  It  burns  with  an  empyreumatic  odor,  and  generally  contains  more 
pyrites  than  ordinary  coal. 

At  Steieregg,  in  Southern  Styria,  brown  coal  occurs  in  the  form  of  a  basin ;  and  has 
been  opened  out  through  a  distance  of  more  than  two  miles.  The  coal,  from  8  to  10  feet 
thick,  is  of  good  quality.  It  contains  9  to  14  per  cent,  of  water,  and  leaves  from  5  to  12 
per  cent,  of  ash  after  combustion. 

The  following  is  an  analysis  of  a  variety  from  Oregon  :  volatile  matter,  49  5  :  fixed  car- 
bon, 42-9  ;  ash,  2-7 ;  water,  4-9  =  100-00. 

A  variety  of  brown  coal,  called  the  paper-coal  of  Rott,  near  Bonn,  and  of  Erpel  on  the 
Rhine,  contains  numerous  remains  of  freshwater  fishes,  Leuciscus  papyraceus  ;  and  of  fro"-s, 
Palmopknjgnos  grandipes.     The  ashes  of  this  coal  are,  also,  rich  in  infusorial  remains. 

For  an  account  of  the  brown  coals  of  this  country,  see  Lignite  and  Boghead  Coal 

n.  w.  B. 

BROWN"  IRON"  ORE  (or  Limonite)  is  one  of  the  most  important  ores  of  iron,  and,  at 
the  same  time,  one  of  the  most  abundant  as  well  as  most  widely  diffused.  It  never  occurs 
crystallized,  but  usually  in  stalactitic,  botryoidal,  and  mammillated  forms,  with  a  fibrous 
structure,  a  silky  lustre,  and  often  a  semi-metallic  appearance ;  it  also  occurs  massive  and 
sometimes  earthy.  In  color  it  is  of  various  shades  of  brown,  generally  dark,  never  brio-ht 
It  affords  a  brownish-yellow  streak,  which  distinguishes  it  from  other  ores  of  the  same  m^tal. 
It  dissolves  in  warm  nitro-muriatic  acid,  and  in  a  matrass  gives  off  water.  Before  the  blow- 
pipe It  blackens  and  fuses,  when  in  thin  splinters ;  with  borax,  it  gives  an  iron  reaction. 
H  =  5  to  5-5  ;  specific  gravity  =  3-0  to  4.  Brown  iron  ore  is  a  hydrated  peroxide  of  iron, 
composed  of  peroxide  of  iron,  85-6,  and  water,  14-4  =  100-0;  but  it  frequently  contains 
small  percentages  of  silica,  alumina,  &c. 

The  principal  varieties  of  this  ore  are  brown  hematite,  comprising  the  compact  and 
mammiUary  varieties,  scaly  and  ochry  brown  iron  ore,  yellow  ochre  constituting  the  decom- 
posed earthy  varieties,  which  are  often  soft,  like  chalk.  Bog  iron  ore  and  clav  iron  stone 
are  sometimes  classed  under  this  head,  but  it  appears  to  us,  especially  as  it  regards  the  lat- 
ter, improperly.  The  hydrated  oxides  of  Northamptonshire  and  Bedfordshire  mav  with 
propriety  be  called  brown  iron  ore. 

Brown  iron  ore  is  found  in  Cornwall,  in  the  cnrlwniferous  limestone  at  Clifton  near 
Bristol,  and  in  the  Forest  of  Dean ;  in  Shetland,  Carinthia,  Bohemia,  Siegen  near  JBonn 
V  lUa  Rica  in  the  Brazils,  and  Peru. 

Brown  Hematite  occurs  at  Talchcer,  in  the  Bengal  coal-bearing  strata,  which  are  prob- 
ably of  Permian  age.     It  is  smelted  with  the  charcoal  made  on  the  spot,  and  produces  iron 


218 


BEUCINE. 


of  excellent  quality.  According  to  the  calculations  of  Professor  Oldham,  it  takes  2^  toub 
of  charcoal  to  produce  1  ton  of  iron. — H.  W.  B.     See  Irox. 

BRUCINE.  (C^^H-^N'-O" ;  syn.  Canimarine,  Yomicine.)  A  very  bitter  and  poisonous 
alkaloid  accompanying  strychnine  in  nux  vomica  and  in  the  false  angustura  bark,  {Brucia 
antidi/seiiterica. ) 

BKYLE  or  BROIL.  A  mining  term.  The  loose  matters  found  in  a  lode  near  the  surface 
of  the  earth  ;  probably  a  corruption  of  Beliievl,  [v:/iic/i  stc) 

BRUSH  WHEELS.  In  light  machinery,  wheels  are  sometimes  made  to  turn  each 
other  by  means  of  bristles  fixed  in  their  circumference  ;  these  arc  called  brush  ■wheels.  The 
term  is  sometimes  applied  to  wheels  which  move  by  their  friction  only. 

BUCKING.  A  juiuing  term.  Bruising  of  the  ore.  A  lucking  iron  is  a  flat  iron  fixed 
on  a  handle,  with  wliich  the  ore  is  crushed  ;  and  a  bucking  plate  is  an  iron  plate  on  which 
the  ore  is  placed  to  be  crushed. 

BUCKTHORN.  {Rhamnus  catharticua.)  This  plant  is  a  native  of  England  ;  it  grows 
to  the  height  of  from  15  to  20  feet ;  its  flowers  are  greenish  colored,  and  its  berries  four- 
seeded.  It  is  the  fruit  of  this  plant  which  is  sold  under  the  name  of  French  berries.  The 
juice  of  these,  when  in  an  unripe  state,  has  the  color  of  saffron  ;  when  ripe,  and  mixed  with 
alum,  it  forms  the  sap-green  of  the  painters ;  and  in  a  very  ripe  state,  the  berries  afford  a 
purple  color.     The  bark  also  yields  a  fine  yellow  dye. 

BUCKWHEAT.  {Bli-  Sarrasin,  Yv.  ;  Buchwcizcn,  Germ.)  The  common  buckwheat 
{Polygonum  fagopyrum ^  from  poly^  many,  and  gonu,  a  knee,  in  reference  to  its  numerous 
joint.s)  is  cultivated  for  feeding  pheasants  and  other  game  ;  and  is  now  being  largely  used 
in  France  and  in  this  country  in  distilleries. 

"  In  France,  besides  being  used  for  feeding  fowls,  pigs,  &c.,  it  is  given  to  horses  ;  and  it 
is  said  that  a  bushel  of  its  grains  goes  further  than  two  bushels  of  oats,  and,  if  mixed  with 
four  times  its  bulk  of  bran,  will  be  full  feeding  for  any  horse  for  a  week.  Its  haulm,  or 
straw,  is  said  to  be  more  nourishing  than  that  of  clover,  and  its  beautiful  pink  or  reddish 
blossoms  form  a  rich  repast  for  bees." — Bauso7i. 

It  has  been  stated  that  the  leaves  of  the  common  buckwheat  (Polygonum  fagopyrw?)) 
yield,  by  fermentati«5n.  Indigo  blue.  On  examining  this  plant,  for  the  purpose  of  ascertain- 
ing whether  this  statement  was  correct,  Schunck  was  unable  to  obtain  a  trace  of  that  coloring 
matter,  but  he  discovered  that  the  plant  contains  a  considerable  quantity  of  a  yellow  coloring 
matter,  which  may  very  easily  be  obtained  from  it.  This  coloring  matter  crystallizes  in 
small  primrose-yellow  needles.  It  is  very  little  soluble  in  cold  water,  but  soluble  in  boiling 
water,  and  still  more  soluble  in  alcohol.  Muriatic  and  sulphuric  acid  change  its  color  to  a 
deep  orange,  the  color  disappearing  on  the  addition  of  a  large  quantity  of  water.  It  dis- 
solves easily  in  caustic  alkalies,  forming  solutions  of  a  beautiful  deep  yellow  color,  from 
which  it  is  again  deposited  in  crystalline  needles  on  adding  an  excess  of  acid.  It  is,  how- 
ever, decomposed  when  its  solution  in  alkali  is  exposed  for  some  time  to  the  air,  being 
thereby  converted  into  a  yellowish-brown  amorphous  substance,  resembling  gum.  Its  com- 
pound with  oxide  of  lead  has  a  liright  yellow  color,  similar  to  that  of  chromate  of  lead.  The 
compounds  with  the  oxides  of  tin  are  of  a  pale  but  bright  yellow  color.  On  adding  proto- 
sulpliate  of  iron  to  the  watery  solution,  the  latter  becomes  greenish,  and,  on  exposure  to  the 
air,  acquires  a  dark  green  color,  and  appears  almost  opaque.  The  watery  solution  imparts 
to  printed  calico,  colors,  some  of  which  exhibit  considerable  liveliness.  Silk  and  wool  do 
not,  however,  acquire  any  color  when  immersed  in  the  boiling  watery  solution,  unless  they 
have  previously  been  prepared  with  some  mordant.  The  composition  of  this  substance  in 
100  parts  is  as  follows : — carbon,  50-00,  hydrogen,  5'55,  oxygen,  44'45.  Its  formula  is 
probably  C^"H""0-°.  It  appears  to  be  identical  with  Rutine,  the  yellow  coloring  matter 
contained  in  the  Ruta  graviolen.'i,  or  common  rue,  and  in  capers ;  and  with  IHxanthlm,  a 
substance  derived  from  the  leaves  of  the  common  holly.  From  1,000  parts  of  fresh  buck- 
wheat leaves,  a  little  more  than  1  part  of  the  coloring  matter  may  be  obtained.  As  the 
seed  of  the  plant  is  the  only  part  at  present  employed,  it  might  be  of  advantage  to  collect 
and  dry  the  leaves,  to  be  used  as  a  dyeing  material. — E.  S. 

The  Tartarian  Buckwheat  {Polygonum  Tartarium)  differs  from  the  former  in  Laving  the 
edges  of  its  seeds  twisted.  It  is  not  considered  bo  productive,  but  it  is  more  hardy,  and 
better  adapted  for  growing  in  mountainous  situations. 

The  Dyers'  Buckwheat.  (Polvf/oman  tinctorium.)  This  plant  was  introduced  to  the 
Royal  Gardens  at  Kew  by  Mr.  John  Blake,  in  ITTG.  Authentic  information  as  to  its 
properties  as  a  dye-yielding  plant  was  only  received  at  a  comparatively  recent  period,  from 
missionaries  resident  in  China,  where  it  has  always  been  cultivated  for  its  coloring  matter. 
In  Europe,  attention  was  first  directed  to  its  growth  by  M.  Delile,  of  the  Jardin  du  Roi  at 
Montpcllier,  who,  in  1835,  obtained  seeds  from  the  Baron  Fischer,  Director  of  the  Imperial 
Gardens  at  St.  Petersburg.  It  has  since  that  time  become  sufficiently  valuable  to  render  its 
cultivation  as  a  dye  drug  of  sufficient  importance.  The  Japanese  are  said  to  extract  blue 
dyes  from  Polygonum  Chinensis,  P.  barbatmn,.o.u'\  the  common  roadside  weed,  P.  avicu- 
lore. — Lawson. 


CABLE.  219 

BUDDLING.  A  mining  term.  The  process  of  separating  the  metalliferous  ores  from 
the  earthy  matters  with  which  they  are  associated,  by  means  of  an  inclined  hutch,  called  a 
huddle.,  over  which  water  flows.  It  is  indeed  but  an  arrangement  for  availing  ourselves  of 
the  action  of  flowing  water  to  separate  the  lighter  from  the  heavier  particles  of  matter. 

BUHL.  Buhl-work  consists  of  inlaid  veneers,  and  differs  from  marquetry  in  being  con- 
fined to  decorative  scroll-work,  frequently  in  metal,  while  the  latter  is  more  commonly  used 
for  the  representation  of  flowers  and  foliage.  Boule,  or  Buhl,  was  a  celebrated  cabinet- 
maker in  France,  who  was  born  in  1642,  and  died  in  1732.  He  was  appointed  "  Tapissier 
en  titre  du  Roi,"  and  he  gave  his  name  to  this  peculiar  process  of  inlaying  wood  with  either 
wood  or  metal.     See  Makquetrt. 

BUHR-STONE,  mineralogically,  is  a  cellular  flinty  quartz  rock,  constituting  one  of  the 
jaspery  varieties  of  the  quartz  family.  A  celebrated  grit-stone,  much  used  in  France  and 
other  parts  of  the  continent  for  grist-mills.  Those  of  La  Ferte-sous-Jonarre  (Seine  ct 
Maine)  are  regarded  as  superior  to  all  others.  In  consequence  of  the  necessity  for  carefully 
piecing  these  stones  together,  they  are  naturally  expensive  ;  yet  the  demand  for  buhr-stones 
continues  great. 

BULRUSH,  or  TALL  CLUB.  {Scirpus  lacustris  ;  Celtic,  cirs,  rushes.)  The  bulrush, 
belonging  to  the  natural  order  of  Cypcraccce,  grows  naturally  on  alluvial  soils  which  are 
occasionally  covered  with  fresh  water.  It  is  much  used  by  coopers  for  putting  between  the 
staves  of  barrels,  and  by  chair-makers.  Many  other  plants  belonging  to  this  order  are  cm- 
ployed  for  economical  purposes,  such  as  forming  seats,  ropes,  mats,  and  fancy  basket-work, 
also  for  thatching  houses.     In  1856,  we  imported  562  tons. 

BURGUNDY  PITCH.  Burgundy  pitch,  when  genuine,  is  made  by  melting  frankin- 
cense {Abieiis  resina)  in  water,  and  straining  it  through  a  coarse  cloth.  The  substance  usu- 
ally sold  as  Burgundy  pitch  is,  however,  common  resin,  incorporated  with  water,  and 
colored  with  palm  oil.  In  some  cases  American  turpentine  is  cmijloyed.  See  Pitch  and 
Tar. 

BURNING  HOUSE.  A  miner's  term.  In  Cornwall  the  kiln  or  oven  in  which  the  tin  and 
other  ores  are  placed  to  sublime  the  volatile  constituents,  sulphur,  and  arsenic,  is  so  called. 

BURROW.     A  miner's  term  for  a  heap  of  rubbish. 

BUTT.     A  measure  for  wine,  &c.,  containing  2  hogsheads,  or  126  gallons. 

BUTYLAMINE  (C^H"N.)  A  volatile  organic  base,  homologous  with  melhylamine.  It 
is  found  in  the  more  volatile  portion  of  bone  oil.  It  may  be  prepared  artificially  by  pro- 
cesses analogous  to  those  employed  for  methylamine,  amylamine,  &c.,  substituting  the 
butylic  cyanate,  urea,  or  iodide,  for  those  of  methyle  and  amyle. — C.  G.  W. 

c 

CABLE.  We  have  avoided  all  relating  to  the  general  history  and  application  of  chain 
cables,  but  in  connection  with  the  following  particulars,  obtained  from  Brown,  Lenox,  and 
Co.'s  chain  works  at  Millwall,  we  must  admit  the  important  part  performed  by  this  house 
in  the  improvement  of  this  manufacture.  The  following  i-emarks  refer  to  chain  cables  for 
the  Royal  Navy,  messenger  and  mooring  chains  for  the  Trinity  Corporation,  and  ship  cables 
for  merchant  service,  showing  the  practice  in  1858. 

After  selecting  the  best  iron,  cutting  it  off"  into  required  lengths,  and  heating  it,  the  links 
for  chain  cables  may  be  bended  at  the  rate  of  about  60  per  minute,  by  machinery  at  Lenox's 
works  in  Wales,  woi-ked  by  water  power, — the  welding  of  the  links,  in  all  cases,  being 
effected  by  hand  labor. 

In  the  practice  with  the  new  hcndinc/  machine  at  New  bridge  Works,  Pont-y-Prid,  Glamor- 
ganshire, it  is  as  follows  : — When  the  iron  is  cut  to  the  requisite  length  for  links,  from  20 
to  60  pieces,  according  to  size,  are  put  into  the  furnace,  and,  when  heated,  are  placed 
separately  on  the  bending  mandrel  g,  {fig.  91,)  the  machine  is  set  in  motion,  and  one  revolu- 
tion forms  a  link  which  is  pinched  off  the  mandrel  by  a  small  crowbar,  and  another  piece 
of  iron  applied,  and  so  on,  until  from  40  to  60  links  arc  formed  in  a  minute. 

The  bending  machine  is  connected  with  a  water-wheel,  or  other  power,  by  an  ordinary 
coupling  clutch,  or  box,  wliich  a  lever  throws  into  and  out  of  gear  at  pleasure. 

There  is  a  stub  or  knob  of  iron  on  the  mandrel  under  which  the  point  of  the  piece  of 
iron  to  be  bent  is  fixed ;  the  mandrel  being  oval,  or  of  the  inside  shape  of  the  link,  when 
turned,  is  followed  by  the  roller  above,  and  this,  pressing  upon  the  piece  of  iron,  forms  it  to 
'the  shape  of  the  mandrel. 

ABC  {fig.  91)  are  standards,  d,  connecting  rod,  e,  crank  for  lifting,  f  f,  the  roller  for 
pressing  sides  of  links,  (;,  mandrel,  ii,  mandrel  spindle,  i,  wheel  for  mandrel  spindle,  j, 
pinion  or  main  spindle,  k,  crank  spindle. 

The  form  of  the  link,  after  being  bended  into  shape,  (^fig.  01,)  is  shown  with  the  two  slant- 
cut  surfaces  of  the  ends  to  I)e  welded  together  and  hammered  into  form. 

For  short  lengths  of  chain,  the  bending  may  be  efi'ectcd  by  hand  ;  in  this  case  the  pro- 


220 


cess  is  simple  : — A  sufficient  length  of  the  best  iron  is  cut  off,  and,  while  hot,  is  partialh- 
bent  by  the  workman  over  an  iron  ring,  one  end  of  the  bar  resting  on  the  ground ;  the 
bend  is  finished  upon  the  anvil ;  one  entire  length  of  the  link  is  thus  formed.  The  two 
slanting  cut  ends  are  made  to  approach  each  other ;  heated  up  to  a  high  temperature,  the 
expert  workman,  by  a  peculiar  blow,  detaches  the  scale  of  oxide,  and  instantly  presses  both 
surfaces  together ;  two  men  then,  by  repeated  blows,  effect  the  welding  junction,  and  thus 
the  link  is  formed. 

The  shape  of  the  link,  after  due  consideration  of  the  advantages  of  particular  patterns, 
seems  to  resolve  itself  into  the  decided  preference  for  a  link  of  parallel  sides,  unchanged  in 
form  from  the  round  of  the  iron  employed,  while  the  ends  may  be  reduced  somewhat 
flattened,  and  increased  in  breadth.  The  links  thus  in  contact  have  the  pressure  sustained 
by  a  greater  breadth  of  surface,  and  compression  can  scarcely  alter  the  form. 

The  length  of  a  good  link  may  be  of  round  iron  6  diameters  in  length  of  link.  (See 
fri.  92.)  A  a  and  from  b  to  6  3'7  to  4  diameters  of  the  iron  rod  employed,  and  1-7  to  2 
diameters  inside. 

The  stud,  staple,  or  cross-bit  is  of  cast-iron,  and  is  placed  across ;  its  use  is  to  prevent 
the  sides  from  collapsing  by  extension  of  the  chain  ;  in  fact,  to  keep  up  a  succession  of 
joints,  and  prevent  the  chain  from  becoming  a  rigid  bar  of  metal. 

The  stud  or  cross-piece  shown  at  c  is  of  cast-iron,  with  dates  and  marks  upon  the  sur- 
face. It  is  cast  with  a  hollow  bearing,  having  a  curve  to  receive  the  round  iron  of  the  link  ; 
its  shoulders,  or  feathering,  enaljlcs  the  workman  to  insert  it  readily,  and  a  few  blows  upon 
the  yielding  iron  give  the  requisite  grip,  and  all  proper  service  only  tends  more  firmly  to 
keep  it  in  position. 

In  all  cases,  this  cross-piece  has  been  of  cast-iron.  Wrought  iron  was  tried,  but  found 
to  be  too  expensive.  Malleable  iron  has  been  patented,  but  it  is  a  question  whether  it  can 
supersede  common  foundry  iron,  from  the  cheapness  and  fiicility  of  the  latter. 

The  caViles  are  proved  and  tested  by  regulated  strains  brought  to  bear  continuously  up 
to  the  proof  strain,  and  then  even  up  to  the  ultimate  destruction  of  some  of  the  links,  if 
t!ie  final  strength  or  opposition  to  resistance  is  required  to  be  known.  The  proof  of  cable 
should  be  GOO  Ihs.  for  each  circle  of  iron  \  of  an  inch  in  diameter. 

Tlie  chain  is  attached  at  one  end  horizontally  to  a  hydraulic  press,  the  other  end  to  the 
enormous  head  of  a  bent  iron  lever,  whose  power  is  multiplied  by  second  and  third  iron 
lovers,  all  working  upon  knife  edges,  and  to  the  last  lever  a  scale-pan  is  attached ;  1  lb. 
being  here  placed  as  equivalent  to  a  strain  of  2,240  lbs.  upon  the  bar  or  chain  that  is  being 
tested.  This  machine  of  Brown,  Lenox,  and  Co.,  Millwall,  is  more  powerful  than  that  used 
in  the  Royal  Dockyard.  The  proving  machine,  invented  by  Captain  Brown  in  1813,  was  a 
great  step  towards  the  production  of  confidence. 

In  practice,  lcn()th  after  hnfjth  is  tried  up  to  the  proof  required  ;  when  the  tension  is  to 
be  exerted  to  the  utmost,  a  few  links  are  taken :  in  such  experiments,  it  is  usual  for  one 


CABLE. 


221 


link  alone  to  give  way,  and  the  strength  of  the  cable  itself  is  uninjured  by  testing  to  find  ita 
ultimate  strength. 

Perfection  of  practice  is  found  when  the  link  and  the  stay  yield  together ;  in  the  largest 
chain  cables  ever  produced,  such  were  the  due  proportions  and  symmetry  of  form  affording 
equality  of  resistance,  that  the  cross-piece  split  or  broke  at  the  time  the  link  fractured  and 
opened. 

To  measure  these  chains,  or  be  near  them  when  under  such  tension,  is  not  without  dan- 
ger. The  cable,  on  being  struck,  rings  out  with  strange  shrill  sound,  a  link  may  suddenly 
snap,  the  chain  lashes  about,  and  the  fragments  fly  to  a  great  distance,  penetrating  the  fac- 
tory roof  at  times,  and,  at  the  moment  of  fracture,  the  link  becomes  very  hot. 

The  cables  are  usually  told  off  into  lengths.  The  Government  length  is  12i  fathoms  ; 
for  the  merchant  service  the  length  is  15  fathoms;  as  explained,  these  lengths  are  united 
by  shackles.  In  the  merchant  service  cables,  larger  links  are  placed  at  eacTi  extremity  for 
the  anchor  shackle  to  pass  through ;  but  in  the  Royal  Navy  cables  each  length  is  alike  pro- 
vided with  large  links  ;  thus,  then,  at  any  time,  any  end  of  any  length  may  be  placed  to  the 
anchor  stock.     See  Jigs.  92,  93. 


To  obviate  evils  from  the  twisting  of  the  chain  cable,  swivels  are  inserted  :  in  the  Gov- 
ernment cables,  a  swivel  is  inserted  in  the  middle  of  every  other  length  ;  for  the  merchant 
service  there  does  not  appear  to  be  any  precise  rule.  Sometimes  one,  two,  or  more  swivels 
may  be  in  100  fathoms ;  and  in  cheap  chains,  bought  and  judged  by  weight  and  figures,  no 
swivel  whatever  exists  in  the  cable. 

The  effect  of  such  twisting,  or  torsion,  is  to  form  a  kink,  and  give  powerful  lateral 
pressure  upon  the  link  ;  the  stud  or  cross-piece  is  forced  out,  and  the  link  itself  may  yield 
at  the  moment  at  any  flaw  or  imperfection  of  welding. 

The  mooring  swivel  is  that  by  which  a  ship  can  ride  with  two  anchors  down  at  the  same 
time,  and  two  bridles  on  board  the  ship.  The  mooring  swivel,  being  equal  in  strength  to 
the  two  cables,  is  over  the  bow,  and  enables  the  ship  to  swivel  round  her  anchors  without 
fouling  hawse ;  in  any  direction  the  ship  can  swing  round  this  swivel  or  point,  leaving  her 
anchors  undisturbed,  whereas,  by  two  cables  out,  without  this,  she  would  require  groat  care 
to  prevent  them  from  fouling,  and  even  being  lost.  This  is  an  essential  advantage  of  chain 
over  hemp. 

The  splicing  shackle  is  to  unite  or  splice  a  hempen  cable  to  be  used  on  board  ship,  at- 
tached to  the  chain  cable,  which  lies  on  the  ground  or  bottom,  so  that  the  vessel  rides 
lightly  at  her  anchor,  while  tlie  iron  chain  cable  preserves  the  hempen  cable  from  being  de- 
stroyed by  the  rocky  bottom,  and  the  ship  has  the  light  hemp  cable  rendered  buoyant  by 
the  water,  which  lifts  portions  of  the  chain  cable  by  tlu^  motions  of  the  vessel ;  and  thus, 
the  ship  is  relieved  from  weight  and  the  anchor  from  jerks. 

The  splicing  shackle,  on  the  Hon.  George  Elliott's  plan,  is  shown  above,  {Jig.  93.)  The 
rope  is  served  round  an  iron  thimble,  a,  on  the  shackle,  n,  with  end  links,"  and  enlarged 
links  without  stay-pins,  c  d,  leading  to  the  anchor,  while  the  hempen  cable,  a,  goes  to  the 
ship. 

In  the  Royal  Navy  4  cables  are  employed  to  moor  the  ships,  two  being  end  to  end. 
-  When  ships  lay  long  on  certain  shores,  the  pin  or  fastening  often  gets  loose  by  the  con- 
stant tapping  and  vibrations  of  the  chain  cable  on  the  rocky  or  shingly  bottoni.  Men-of-war 
at  some  stations  suffered  severely  in  this  way,  and  the  commander  at  Malta  had  reason  to 
represent  it  as  a  very  serious  matter.  Mr.  Lenox's  plan  for  securing  the  bolts  and  pins  is 
now  made  a  point  of  contract  to  be  adopted  in  all  fastenings  for  the  Royal  Navy. 

Simple  as  it  would  seem  to  devise  a  plan,  yet  it  was  years  before  all  the  difficulties  could 
be  surmounted.     This  arrangement  may  be  understood  by  reference  to  the  figure  of  a 


222 


CABLE. 


^zy 


shackle  with  links,  {fig.  94  :)  at  e  is  seen  the  aperture  at  right  angles  to  the  bolt,  f,  (of  oval 
iron ;)  through  this  channel,  cut  through  the  shackle  and  the  bolt,  a  tapering  but  not  quit 

cylindrical  steel  pin  fits  exactly,  but  does  not 
quite  proceed  through  the  iron ;  it  is  shown 
at  g  g.  Various  plans  used  to  be  resorted  to 
before  this  final  preference  ;  for  the  steel  pins, 
of  whatever  form,  got  loose  by  repeated  tap- 
ping on  the  rocky  bottom,  or  the  links  upon 
each  other.     Mr.  Lenox  succeeded  in  cutting 

c ^ =^— — ...^  the  cavity  at  e  of  the  form  of  a  hollow  cone, 

^  ^  \  /  ,^_X^,?;^^1^^  ^^^  *^  complete  the  fastening,  a  pellet  or  cyl- 
inder of  lead  that  will  just  allow  insertion  at  i; 
is  driven,  and  then,  by  rtpeated  blows,  the  lead 
is  made  to  fill  up  the  cavity,  the  superfluous 
quantity  of  lead  being  cut  oft" by  the  hammer  at 
E.  To  release  the  bolt,  it  is  only  necessary  to 
find  the  small  space  at  the  small  end  of  the  steel  pin,  to  insert  a  punch,  and  then,  with  a  few 
blows,  the  steel  pin  g  g  is  driven  out  of  its  conical  bearing,  and  its  flat  top  and  cutting  edges 
enable  it  to  emerge  again  at  e.  Being  forced  out,  the  bolt  f  is  taken  out,  and  the  chain 
severed,  if  required ;  the  aperture  at  e  can  be  cleared  of  its  lead  by  a  proper  cutting-out 
tool,  and  the  steel  pin  replaced  to  make  all  fast. 

This  operation  can  be  effected  on  the  darkest  night ;  the  sailor  can  sever  the  chain  cable, 
and  thus,  when  one  vessel  is  driving  down  upon  another,  more  chain  may  be  attached,  or 
the  cable  severed,  and  no  harm  done  ;  while  with  hempen  cable  it  might  be  found  more 
than  difficult,  and  even  impossible,  to  cut  them  in  time. 

All  the  principles  involved,  and  perfection  of  practice,  in  making  chains  and  chain  cables, 
have  recently  be(?li  deeply  considered  and  fully  verified  by  the  firm  of  Brown,  Lenox,  and 
Co.,  Millwall,  who,  for  the  purpose  of  obtaining  comparative  results  up  to  the  greatest  links 
required  for  the  "  Leviathan,"  selected  iron  of  the  same  identical  quality  and  worked  it  into 
rods,  links,  and  chains.  The  progression  of  resistance  to  increased  strains,  by  increase  of 
mass  of  iron,  with  all  the  influences  of  variation  of  make,  flaws  in  the  material,  and  oth.cr 
circumstances  inseparable  from  practice,  were  thus  matters  of  critical  experiment. 

Commencing  with  ^-inch  chain,  and  trying  4  links  of  small  chains  up  to  2|,  being  the 
largest  diameter  of  round  iron  for  the  greatest  cable  links  ever  hitherto  made,  being  those 
for  the  sheet  anchor  of  the  "  Leviathan,"  taking  the  breakirg  strains,  and  reducing  all  the 
links  to  the  proportion  borne  upon  a  circle  ^  of  an  inch  in  diameter,  the  minimum  breaking 
force  was  796-25  lbs.,  and  the  maximum  1052'8  lbs. 

Sometimes  the  fracture  was  found  to  be  dependent  upon  flaws,  sometimes  from  over- 
heating, or  unequal  heating,  and  other  practical  causes  ;  but  the  whole  series  of  experiments 
was  important  and  interesting. 

The  iron  lengthens  to  the  intense  strains  employed,  long  before  fracture.  The  com- 
parison of  actual  extension,  while  under  enormous  force  at  ordinary  temperatures,  was  as- 
certained by  the  following  impressive  experiments  : — 

The  "  Leviathan  "  second-size  cable  of  2f  diameter  of  iron  employed  in  the  links.  Three 
links  measured  35^  inches  by  strain  of  10  tons,  (of  course,  it  requires  power  to  extend  them 
fairly.) 

At     50  tons stretched  \  of  an  inch. 

u  II  u 

-  -  "       H 

-     -      "    n 

-Tff 

-  -  "  3i 
"  8-J- 
"       3f 

A  few  links  of  the  best  bower  anchor  cable  of  the  "  Leviathan  "  taken,  proved,  and 
destroyed. 

Three  links  measured  at  15  tons  39  inches. 


85 

110 

(Proof)  " 

124 

140 

150 

160 

170 

ind  broke  " 

180 

At     75  tons 


125 

(Proof)  " 

148| 

IGO 

170 

180 

190 

200 

It  bore  " 

217 

And  broke  " 

218 

stretched  J  of  an  inch. 
"       If 
"       2^- 
"       3  " 

"       3i 


H 


CALICO  PKINTING.  223 

CACAO.  The  Theobroma  Cacao  (or  Food  of  the  Gods,  as  Linnaeus  named  the  tree)  is 
a  native  of  the  West  Indies  and  of  continental  America,  Its  seeds,  {nuclei  Cacao,)  when 
torrefied,  and  with  various  additions  (sugar,  and  usually  either  cinnamon  or  vanilla)  made 
into  a  paste,  constitute  Chocolate,  (chocolata,)  wliich  furnishes  a  very  nourishing  bev- 
erage, davoid  of  the  injurious  properties  ascribed  to  both  tea  and  coffee  ;  but  which,  on  ac- 
count of  the  contained  oil,  is  apt  to  disagree  with  dyspepti(!S.  Cocoa  is  another  preparation 
of  these  seeds.  It  is  said  to  be  made  from  the  fragments  of  the  seed-coats,  mixed  with 
portions  of  the  kernels. — Pereira.     See  Chocolate. 

CAIRNGORUM,  or  CAIRNGORM  is  the  name  generally  applied  to  the  more  pellucid  and 
paler-colored  varieties  of  smoky  quartz,  with  a  tint  resembling  that  of  sherry  or  amber.  It 
is  so  called  from  the  district  Cairngorum,  or  the  "  Blue  Mountain,"  in  the  south-west  of 
Banff,  where  these  crystals  are  frequently  found.  When  of  a  good  color,  this  crystal  is 
made  into  ornaments,  and  used  for  jewellery  ;  indeed,  so  great  a  favorite  is  the  Cairngorum 
witli  the  people  of  Scotland,  that  brooches,  pins,  bracelets,  and  a  variety  of  ornaments,  are 
made  with  this  stone,  for  use  by  all  classes. 

CALAMANDER.     A  wood,  the  produce  of  Ceylon.     See  Coromandel. 

CALAMINE.  A  native  carbonate  of  zinc.  (See  Zinc.)  The  term  Calamine,  or  Lapis 
calnininariH,  has  been  applied  to  this  ore  of  zinc  since  the  days  of  the  Arabian  alchemists. 
It  is  so  used  now  by  Brook  and  Miller,  by  Greg  and  Lettsom,  and  others ;  yet  we  find  Dana 
defining  calamine  to  be  the  hjidroufi  silicate  of  zinc, — another  example  of  the  sad  want  of 
system,  and  indeed  of  agreement,  among  mineralogists. 

CALCAREOUS  EARTH  {lerre  cak-aire,  Fr.  ;  Kalkerde,  Germ.)  commonly  denotes 
lime,  in  any  form  ;  but,  properly  speaking,  it  is  pure  lime.  This  term  is  frequently  applied 
to  marl,  and  to  earths  containing  a  considerable  quantity  of  lime. 

CALCAREOUS  SPAR.  Crystallized  native  carbonate  of  lime,  of  which  there  are  many 
varieties. 

Carbonic  acid  44"0,  lime  56'0,  may  be  regarded  as  the  usual  composition  of  calc  spar;  it 
often  contains  impurities,  upon  which  depend  the  colors  assumed  by  the  crystal.  The  car- 
bonates of  lime  are  extensively  distributed  in  nature,  as  marbles,  chalk,  and  cr)'stalline 
minerals. 

CALCAREOUS  TUFA.  This  term  is  applied  to  varieties  of  carbonate  of  lime,  formed 
by  the  evaporation  of  water  containing  that  mineral  in  solution. 

It  is  formed  in  fissures  and  caves  in  limestone  rocks,  about  the  borders  of  lakes,  and 
near  springs,  the  waters  of  which  are  impregnated  with  lime.  In  the  latter  cases  it  is  fre- 
quently deposited  upon  shells,  moss,  and  other  plants,  which  it  covers  with  a  calcareous 
crust,  producing  frequently  a  perfect  representation  in  stone  of  the  substance  so  enveloped. 
— H.  W.  B. 

CALCEDONY.     See  Chalcedony. 

CALCINATION,  (from  Calcine.)  The  operation  of  expelling  from  a  substance,  by 
heat,  either  water,  or  volatile  matter  combined  with  it.  Thus,  the  process  of  burning  lime, 
to  expel  the  carbonic  acid,  is  one  of  calcination.  The  result  of  exposing  the  carbonate  of 
magnesia  to  heat,  and  the  removal  of  its  carbonic  acid,  is  the  production  of  calcined  mag- 
nesia. This  term  was,  by  the  earlier  chemists,  applied  only  when  the  substance  exposed  to 
heat  was  reduced  to  a  calx,  or  to  a  friable  powder,  this  being  frequently  the  oxide  of  a 
metal.     It  is  now,  however,  used  when  any  body  is  subjected  even  to  a  process  of  roasting. 

CALCIUM.  {Equivalent  20.)  The  metal  contained  in  the  oxide  well  known  as  lime. 
It  was  first  obtained  by  Davy,  in  1808,  by  the  electrolysis  of  the  hydrate,  carbonate,  chlo- 
ride, or  nitrate  of  lime.  Matthiessen  obtains  it  by  heating,  in  a  porcelain  crucible,  a  mix- 
ture of  two  equivalents  of  chloride  of  calcium,  with  one  equivalent  of  chloride  of  strontium, 
and  muriate  of  ammonia,  until  the  latter  is  volatilized.  The  current  from  six  cells  of  Bun- 
sen's  battery  is  then  sent  through  the  mixture  by  a  cliarcoal  pole  of  as  largo  size  as  possible, 
and  a  piece  of  iron  piano-forte  wire  (No.  G)  not  more  than  two  lines  in  length,  which  is 
united  with  the  negative  pole  of  the  battery  by  means  of  a  stronger  wire  reaching  close  to 
the  surface.  A  small  crust  is  to  be  formed  round  the  wire  at  the  surface.  To  collect  the 
small  globules  deposited  on  the  wire,  the  latter  must  be  taken  out  every  two  or  three  minutes, 
together  with  the  crust.  The  globules  are  crushed  in  a  mortar,  an<l  the  fiattened  granules  are 
then  picked  out.  Calcium  is  a  l)rilliant  pale  yellow  metal,  malleable  and  ductile.  See  Lime. 
— C.  G.  W. 

CALICO  PRINTING  is  the  art  of  producing  a  pattern  on  cotton  cloth,  by  printing  in 
colors,  or  mordants,  which  become  colors,  when  sub.sequently  dyed.  Calico  derives  its  name 
from  Calicut,  a  town  in  India,  formerly  celebrated  for  its  manufactures  of  cotton  cloth,  and 
where  calico  was  also  extensively  printed.  Other  fabrics  than  cotton  are  now  printed  by 
similar  means,  viz.  :  linen,  silk,  wool,  and  mixtures  of  wool  and  cotton.  Linen  was  for- 
merly the  principal  fabric  printed,  but  since  modern  improvements  have  produced  cotton 
cloth  at  a  comparatively  cheap  rate,  linen  fabrics  are  now  sparingly  used  for  printing,  and 
then  principally  for  handkerchiefs,  linen  clotii  not  producing  such  beautiful  colors,  in  conse- 
quence of  the  small  affinity  of  fiax  for  mordants,  or  coloring  matters.     Silk  printing,  also, 


224 


CALICO  PRINTING, 


is  chiefly  confined  to  handkerchiefs,  but  the  printing  of  woollen  fabrics  or  mousseline  de 
laines  is  an  important  branch  of  the  art. 

The  first  step  in  calico  printing  is  to  remove  the  fibrous  down  from  the  surface  of  the 
cloth,  which  is  done  by  passing  the  piece  rapidly  through  a  flame  of  gas,  or  over  a  red-hot 
semicircular  plate.  The  latter  method  will  be  found  described  under  the  head  of  Bleach- 
ing ;  the  former  is  performed  as  follows  : — Fig.  95  is  a  vertical  section  of  the  gas-singeing 

95 


AA 


apparatus.  Its  diameter  is  such  as  to  admit  of  pieces  of  the  greatest  width.  The  pipe  a 
runs  along  from  end  to  end  under  the  machine,  and  is  supplied  with  ordinary  gas  ;  the  pipes 
B  B  are  branched  into  this,  being  five  in  number  on  each  side.  Connected  with  these 
branches  are  the  pipes,  c  c,  which  are  perforated  with  fine  holes,  at  distances  of  about  ^  of 
an  inch ;  the  pipes  b  b  are  furnished  with  taps,  a  a.  Above  the  tubes  c  c  are  the  pipes,  d  d, 
which  are  cut  open  at  the  bottom  along  the  length,  and  communicate  by  the  branch  pipes, 
F  F,  with  the  large  pipe,  e,  which  is  exhausted  by  a  fan.  Two  pairs  of  cylinders,  g  g,  of 
wood,  covered  with  fustian,  turn  on  their  axes  in  the  direction  of  the  arrows,  and  draw 
through  them  the  pieces  d  cl  with  a  velocity  of  about  4  feet  per  second.  The  pair  of  rollers, 
G  G,  to  the  right,  are  moved  by  a  belt  and  pulley  ;  the  other  pair  is  moved  by  belts  which 
embrace  the  under  roller  of  each  pair,  h  h  are  brushes,  ia  pairs,  which  remove  the  loose 
down.  The  rubber,  i  i,  of  wood,  covered  with  fustian, 'serves  to  extinguish  any  sparks  that 
might  be  drawn  on  with  the  cloth.  In  using  this  machine,  the  two  rows  of  gas  are  lighted, 
and  the  size  of  flame  regulated  by  the  taps  till  it  burns  blue,  and  in  one  continuous  line  of 
fire ;  the  drawing  rollers  are  then  made  to  revolve,  and  the  end  of  the  first  piece  being  laid 
between  the  left  rollers,  is  drawn  through  by  means  of  a  narrow  piece  of  list  fastened  to  it ; 
the  end  of  the  piece  once  through  the  right  rollers,  the  operation  proceeds  rapidly,  the 
pieces,  of  course,  being  stitched  end  to  end. 

This  gas-singoing  apparatus  has  the  effect  of  making  cloth  appear  thinner  than  it  really 
is,  in  consequence  of  the  flame  passing  through  tlic  fibres,  and  not  merely  on  the  surface. 
It  is,  therefore,  not  so  much  used  as  the  hot  plate.  In  France  and  Germany  a  machine 
called  the  toiuleuac  is  used,  and  which  is  very  similar  to  the  shearing  machine  used  in  the 
manufacture  of  woollen  cloth.  (See  Woollen  Manufacture.)  A  series  of  knives,  running 
spirally  round  a  roller,  shave  off  the  down  by  the  roller  revolving  on  its  axis  as  the  cloth 
passes  underneath.  This  machine  makes  the"  cloth  smoother  and  more  free  from  flaws  or 
lumps  than  either  of  the  other  machines,  but  is  not  yet  used  in  England. 

Tlic  bleaching  requisite  for  printing  cloths  is  of  much  superior  nature  to  that  sufiicient 
for  calico  intended  to  ))e  sold  in  the  white  state.  It  is  sufficient  for  the  latter  to  be  white 
enough  to  iiloasc  the  eye,  a  result  easily  obtained  by  chlorine  treatment  after  a  compara- 
tively mild  alkaline  boiling ;  but  the  former  must  be  so  well  boiled  with  lime  and  alkali,  as 
to  remove  every  particle  of  resinous  and  glutinous  matter  previous  to  the  chlorine  steep. 
This,  if  not  attended  to,  becomes  a  source  of  great  annoyance  to  the  printer  in  his  subse- 
quent operations,  from  the  difficulty  of  obtaining  sufficiently  good  whites  without  injuring 
the  colors.  The  high-pressure  kiers  patented  by  Barlow,  aiid  which  are  fully  described  in 
the  article  Bleaching,  have  been  found  to  facilitate  the  thorough  scouring  of  the  cloth  very 
much  at  a  less  cost  than  the  old  kiers. 


CALICO  FEINTING. 


225 


Till  about  the  year  1760,  the  printing  of  linens  or  calicoes  was  done  by  hand,  wooden 
blocks  being  employed,  on  which  the  pattern  is  raised  in  relief.  About  this  time  a  modifi- 
cation of  the  press  used  for  printing  engravings  was  adapted  to  printing  with  flat  engi'aved 
copper  plates  on  fabrics.  This  press  was  used  to  produce  certain  styles  only,  generally  sin- 
gle colors,  where  delicacy  of  outline  was  required,  shaded  or  stippled  work  being  also  intro- 
duced. The  printing  by  blocks  in  several  colors  was  the  principal  mode  still,  till,  in  1785, 
the  cylinder  printing  machine  was  invented  by  a  Scotchman  named  Bell,  and  brought  into 
successful  use  at  Mossuly,  near  Preston,  by  the  house  of  Livesey,  Hargreaves,  and  Co.  The 
house  of  Oberkampf,  of  Jouy,  in  France,  almost  immediately  adopted  the  invention,  and 
have  been  frequently  considered,  in  France  at  least,  the  originators  of  the  machine  ;  but  it 
is  now  pretty  certain  that  tlie  honor  of  the  invention  is  due  to  Great  Britain.  The  intro- 
duction of  the  cylinder  machine  gradually  caused  the  disuse  of  the  flat  press,  the  London 
printers  continuing  to  use  them  long  after  the  Lancashire  printers  had  given  them  up ;  the 
first  cylinder  machine  was  used  in  London  in  1812.  Blocks  are  still  freely  used  for  some 
description  of  prints,  such  as  woollen  or  mousseline  de  laine  goods,  and  also  for  introducing 
colors,  after  printing  by  the  cylinder  and  dj'eing,  &.c. — the  cylinder  not  being  capable  of 
fitting  in  colors,  after  the  piece  has  once  left  the  machine.  A  blocking-machine,  called  the 
Perrotine,  was  introduced  in  France  in  1834  by  M.  Perrot,  and  is  still  extensively  used 
there,  but  though  tried  in  this  country,  it  never  came  into  general  use.  It  executes  as 
much  work  as  twenty  hand  printers,  and  for  the  special  purposes  for  which  it  was  invented 
is  a  satisfactory  machine ;  the  patterns  capable  of  being  printed  by  it  are,  however,  limited 
in  size,  in  consequence  of  the  narrow  width  of  the  blocks.  Surface  printing,  or  printing 
from  cylind3r*engraved  in  relief,  was  an  invention  preceding  by  a  few  years  the  engraved 
copper  cylinder,  but  apparently  not  in  general  use.  Li  1800,  a  Frenchman  named  Ebingar 
patented  somewhat  the  same  sort  of  thing,  and  in  1805,  James  Burton,  of  the  house  of 
Peel,  at  Church,  invented  the  mule  machine,  which  worked  with  one  or  two  engraved  cop- 
par  cylinders,  and  one  or  two  wooden  rollers  engraved  in  relief.  This  machine  is  very  little 
used  now,  the  impression  produced  by  it  not  having  the  precision  of  that  from  copper  roll- 
ers, and  improvements  in  engraving  copper  rollers  having  given  the  printer  many  of  the 
advantages  possessed  by  the  surface  roller.  Quite  lately,  however,  Mr.  James  Chadwick  has 
patented  a  species  of  surface  roller  which  promises  to  become  useful.  The  ordinary  stereo- 
typed patterns  described  hereafter  are  adapted  by  screws  to  a  brass  or  other  metal  roller, 
which  is  then  fitted  on  the  mandrel  used  with  the  ordinary  engraved  rollers,  and  a  firmness 
and  solidity  thus  given  which  was  never  possessed  by  the  wooden  surface  roller. 

In  block  printing  every  color  is  printed  separately,  the  printer  going  all  through  the 
piece  with  one  block  ;  the  rest  of  the  colors  are  next  separately  fi^tted  into  their  places  by 
the  appropriate  blocks,  and  the  piece  is  then  ready  for  the  subsequent  operations  for  rais- 
ing the  colors.  Calico  intended  for  printing  by  block  is  always  smoothed  by  the  calender, 
the  object  being  to  leave  the  cloth  stiff,  so  as  to  facilitate  the  printer  joining  the  diftercnt 
block  impressions.  When  pieces  that  have  been  printed  by  machine  are  required  to  have 
other  colors  inserted  by  block,  as,  for  instance,  the  grounding-in  of  blues,  yellows,  greens, 
&c.,  after  printing  and  dyeing  in  madder  colors,  the  same  sort  of  process  is  adopted,  the 
pieces  being  dried  and  calendered,  and  then  printed  by  blocks  technically  termed  grounds ; 
these  grounds  are  cut  from  sketches  or  tracings,  taken  from  the  dyed  piece  when  calen- 
dered, and,  consequently,  fit  accurately  those  parts  which  are  intended  to  be  blocked.  The 
grounding-in  of  colors,  after  the  operations  of  dyeing,  was  formerly  done  by  pencils,  which 
were  merely  small  thin  pieces  of  wood,  which  were  dipped  in  the  color,  and  the  necessary 
portions  of  the  patterns,  such  as  leaves,  &c.,  painted  in  by  hand.  Of  course,  this  method 
soon  gave  way  to  blocks ;  but  the  use  of  these  pencils  was  continued  down  to  a  compara- 
tively recent  period  for  certain  colors,  such  as  pencil-blue,  which,  being  a  solution  of  reduced 
indigo,  was  too  speedily  oxidized  when  spread  on  the  sieve,  and  required  instant  applica- 
tion of  the  pencil.  Even  this  color  was  eventually  applied  by  block,  by  a  peculiar  kind  of 
sieve. 

Of  late  years  the  tedious  hand  labor  of  cutting  or  coppering  blocks  has  beep  much  re- 
duced by  stereotyping ;  when  the  pattern  has  several  repeats  on  the  block,  a  casting  in 
type-metal  being  made  of  the  pattern,  and  as  many  of  these  as  requisite  arranged  on  a  plain 
block,  and  securely  nailed  down.  It  is  obvious  that  the  matrix  once  made,  an  infinite  num- 
ber of  castings  can  be  easily  produced ;  the  skilled  labor  is  therefore  reduced  to  a  small  por- 
tion of  what  was  formerly  requisite.  The  ordinary  way  of  making  the  mould  is  to  draw  or 
trace  on  a  small  block  of  pear  tree,  (sawn  across  the  grain,  so  that  the  pattern  is  put  on  the 
end  of  the  grain,)  the  pattern  to  be  typed.  Slips  of  copper  of  varying  thickness,  but  uni- 
-form  width,  are  then  driven  down  to  a  certain  distance  in  the  wood,  just  as  in  the  ordinary 
way  of  coppering  blocks.  When  the  pattern  is  thus  completed,  the  slii)S  are  pulled  out,  of 
course  leaving  the  pattern  indented  in  the  wood  ;  the  block  is  now  rubbed  with  chalk,  and  a 
border  about  Vie  of  an  inch  deep  of  card  nailed  round  the  block.  Melted  type-metal  is  now 
run  in  level  with  the  top  of  the  card,  and  when  cold,  a  tap  with  a  hammer  on  the  under 
side  of  the  block  easily  detaches  the  type,  which  requires  very  little  trimming  to  be  ready 
Vol.  III.— 15 


226 


CALICO  FEINTING. 


for  putting  on  the  block  ;  when  a  number  of  these  are  arranged  on  a  block,  the  surface  is 
tiled  and  ground  on  a  stone  till  perfectly  level.  The  introduction  of  Burch's  patent  typing 
machine,  still  further  simplified  the  stereotyping  process.  In  this  beautiful  invention  the 
matrix  is  formed  by  steel  punches  of  varying  shapes,  which  are  moved  up  and  down  by  a 
stirrup  and  lever,  and  which  are  kept  heated,  by  a  gas  flame  ingeniously  applied,  to  the 
temperature  sufficient  to  char  wood,  and  by  moving  the  block  about  under  these  punches 
and  depressing  them,  the  pattern  is  burnt  into  the  wood  to 
a  uniform  depth,  and  the  labor  of  cutting  and  bending  slips 
of  copper,  &c.,  done  away  with. 

The  Tobying  sieve  is  a  mode  of  applying  with  one  block 
several  colors  at  once,  whereby  the  cost  of  several  blocks  is 
saved,  and,  what  is  of  more  consequence,  the  cost  of  labor  is 
very  much  reduced,  as  one  printer  produces  the  same  result 
as  the  combined  efforts  of  several. 

Whenever  designs  are  composed  of  colored  parts,  where 
each  color  lies  separate,  and  where  the  outlines  of  the 
colored  parts  are  not  too  close  together,  a  sieve  of  the  fol- 
lowing construction  is  made  use  of,  [fig.  96  :) — A  block  of 
wood  is  scooped  out  in  hollow  compartments,  e,  which  vary 
in  size  and  number,  according  to  the  number  and  extent  of 
the  shades  to  be  printed  ;  these  compartments  communicate 
by  tubes,  b,  at  the  bottom,  with  reservoirs,  A^t  the  sides  of 
the  sieves  ;  over  the  compartments  is  then  stretched  tightly 
a  woollen  sieve ;  the  surface  of  this  cloth  is  cemented  with 
melted  resin  string  about  ^  of  an  inch  thick,  following  the 
configurations  of  the  compartments ;  the  use  of  this  is  to 
prevent  the  colors  mixing  and  becoming  blended  at  the 
edges.  Colors  are  now  put  in  the  reservoirs,  which  are  kept 
filled  up  above  the  height  of  the  cloth,  so  that  a  gentle  pres- 
sure is  exerted  against  the  under  side  of  the  sieve.  The 
colors  are  made  of  such  a  thickness  as  to  pass  through  the 
cloth,  and  keep  the  upper  surface  moist,  but  still  not  too 
thin,  or  they  would  spread  when  printed.  The  sieve  being 
thus  prepared,  the  block  is  famished  with  guides,  which, 
working  against  the  sides  of  the  sieve  frame,  constrain  the 
block  to  be  always  dipped  in  one  place,  and  thus  each  part 
of  the  pattern  finds  itself  furnished  with  its  proper  color. 
Sometimes  the  compartments  for  the  colors  axe  made  of  metal  when  required  to  be  durable, 
so  as  to  serve  for  a  large  number  of  pieces  of  th«  same  pattern. 

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Where  colors  are  required  to  melt  into  one  another,  technically  called  rainbowcii, 
(/onrfws,  Fr.,)  the  following  apparatus  is  used: — a  a  {fifj.  97)  is  a  rectangular  frame  of 


CALICO  PRINTING. 


227 


wood,  about  6  inches  deep,  2  feet  long,  and  about  1  foot  broad.  On  this  frame  is  stretched, 
by  means  of  small  hooks,  a  woollen  cloth,  and  the  frame  then  laid  on  the  elastic  surface  of 
the  usual  swinwdng  tub,  the  cloth  downwards  and  pasted  or  gummed  to  the  oilskin  cover 
of  the  tub.  At  one  end  is  now  put  the  color  reservoir  b  b,  which  consists  of  a  wooden  or 
metal  box,  divided  into  water-tight  compartments  longitudinally  by  strips  of  thin  metal ; 
this  box  is  of  such  a  width  a^  to  tit  easily  into  one  end  of  the  frame,  and  resting  on  a  board 
of  the  same  size,  fixed  across  the  frame  ;  the  depth  of  the  box  may  be  about  4  inches,  and 
the  width  about  8  inches ;  but  this  is  regulated  by  the  number  of  colors  to  be  blended  or 
ralnbowed.  A  semicircular  piece  of  wood,  of  nearly  the  same  width  as  the  frame,  is  cov- 
ered with  printer's  blankets,  and  a  handle  formed  on  the  top,  so  that  the  teerer  can  move  it 
backwards  and  forwards.  The  color  lifter,  c  c,  is  a  flat  piece  of  wood  just  covering  the 
color  box ;  on  the  under  side  of  this  are  inserted  wooden  pegs,  as  d,  at  certain  places  de- 
termined by  the  width  of  the  stripe  of  rainbowed  color,  and  the  number  of  shades  composin"- 
it.  These  pegs  are  of  turned  wood,  about  ^  of  an  inch  thick  at  the  small  end,  and  about  # 
of  an  inch  at  the  thick  end,  this  end  being  also  recessed  so  as  to  lift  more  color ;  they  are 
nearly  as  long  as  the  color  box  is  deep.  In  the  figure,  suppose  it  is  desired  to  produce  on 
the  sieve  two  stripes,  say  E  of  dark  green  in  centre,  and  two  shades  of  green  at  each  side, 
and  F  of  chocolate  in  centre,  purple  next,  and  drab  next,  at  each  side,  the  color-box  is  filled 
thus  : — in  No.  1  compartment  is  put  the  darkest  green ;  in  No.  2,  the  medium  green  ;  in 
No.  3,  the  palest  green ;  in  No.  4,  the  chocolate  ;  in  No.  5,  the  purple ;  and  in  No.  6,  the 
drab.  The  color  lifter  is  so  studded  with  pegs,  that  when  put  in  the  color-box,  the  pegs  1, 
2,  3,  4,  5,  and  6  respectively,  dip  into  their  appropriate  colors.  The  brush,  or  semicircular 
roller,^  G,  is  then  moved  up  to  the  top,  as  shown  in  the  dotted  lines,  the  color  lifter  being 
then  lifted  up  out  of  the  color-box  is  held  a  moment  till  the  color  has  ceased  dropping  from 
the  pegs,  and  then  lifted  over,  and  the  pegs  allowed  to  deposit  the  color  on  the  sieve,  as 
shown  by  the  black  spots  1,  2,  3,  4,  5,  and  6.  The  lifter  is  then  returned  to  the  box,  and  a 
fresh  portion  of  color  lifted,  and  deposited,  as  befojre,  at  a  different  part  of  the  sieve,  the 
spots  of  color  being  of  necessity  all  in  straight  lines ;  the  brush,  g,  is  then  moved  back- 
wards and  forwards  by  the  teerer  till  the  colors  are  sufficiently  rubbed  together  or  blended 
at  the  edges.  It  is  necessary  to  observe,  that  the  thickness  of  the  colors  must  be  pretty 
uniform,  and  sufficiently  thin  to  allow  them  to  mix  at  the  edges.  By  this  means  one  color 
is  made  to  melt  insensibly  into  another,  and  a  beautiful  shaded  effect  produced  on  the  sieve, 
and  consequently  on  the  piece,  when  printed  from  a  block  dipped  on  it. 

The  annexed  cuts  are  taken  from  the  "  Traite  de  I'lmpression  des  Tissus,"  of  M.  Persoz. 

Fig.  98  is  a  vertical  section,  and7?y.  99  an  elevation. 


A,  cast-iron  framework,    b  b  b,  cast-iron  tables,  planed  smooth,  over  which  circulate  the 
blanket,  the  backcloth,  and  the  piece  that  is  printed ;  c  c  c,  sliding  pieces,  to  which  the  block 


228 


CALICO  PRLS'TIXG. 


holders,  3,  are  screwed,  and  causing  the  engraved  blocks,  2,  to  more  alternately  against  the 
woollen  surface,  from  which  they  receive  the  colors  and  the  stuff  to  be  printed,  by  the  action 
of  the  arms,  4  and  5,  the  supports  of  which,  6,  rest  on  the  frame,  a,  and  which  act,  through 
the  medium  of  connecting  rods,  on  the  beams,  7,  keyed  to  the  slides,  c.  The  lower  of  these 
slides,  being  in  a  vertical  position,  takes  by  its  own  weight  a  retrograde  movement,  regulated 
by  a  counterweight,  e  e  e  are  movable  color-sieves,  keyed  to  connecting  rods,  and  receiv- 
ing from  the  power  applied  to  the  machine  the  kind  of  movement  which  they  require. 
These  sieves,  which  are  flat,  and  covered  with  cloth  on  the  surface  opposite  to  the  blocks, 
slide  in  grooves  on  the  sides  of  the  tables,  and  receive  from  the  furnished  rollers  the  colors 
which  they  aften^ards  transmit  to  the  blocks,  f  f  f  are  the  color  troughs  filled  with  color, 
and  furnished  each  with  two  rollers,  8  and  10,  the  last  of  which,  dipping  into  the  troughs, 
are  charged  with  color,  which  they  communicate  to  the  roller,  8,  the  latter  being  covered 
with  woollen  cloth  ;  and  these,  in  their  turn,  transmit  their  color  to  the  sieves,  e,  on  which 
it  is  spread  by  the  fixed  brushes,  9.  As  it  is  important  to  be  able  to  vary  at  pleasure  the 
quantity  of  color  supplied  to  the  sieves,  and  consequently  to  the  blocks,  the  rollers,  10, 
are  in  connection  with  levers,  11,  which,  by  means  of  adjusting  screws,  bring  them  into 
more  or  less  intimate  contact  with  the  rollers,  8,  and  consequently  vary  the  charge  of  color 
at  pleasure. 

The  blanket,  backcloth,  and  fabric  are  circulated  as  follows  : — At  the  four  angles  formed 
by  the  three  tables,  b,  are  rollers,  1,  armed  on  their  surface  with  needle  points,  which  pre- 
vent the  cloths  from  slipping  as  they  pass  round,  and  thus  secure  the  regular  movement  of 
the  stuff  to  be  primed,  a  movement  determined  by  the  toothed  wheels,  21,  {fg.  99,)  fixed  at 


the  extremities  of  the  axes  of  these  rollers,  g  is  a  roller  for  stretching  the  endless  web, 
resting  with  the  two  ends  of  its  axes  on  two  cushions  forming  the  extremities  of  the  screws, 
12,  by  which  the  roller  can  be  pushed  further  out  when  required,  to  give  the  cloth  the  neces- 
sary tension,  n  is  another  tension  roller,  supporting  the  blanket  and  backcloth.  k  is  a 
roller  which  serves  similar  purposes  for  the  blanket,  the  backcloth,  and  the  fabric  in  course 
of  being  printed,  t,  the  blanket,  which  in  its  course  embraces  the  semicircumference  of 
the  roller,  g,  passes  over  the  roller,  n,  and  behind  k,  to  circulate  round  the  cylinders,  1, 
and  over  the  surfaces  of  the  tables,  b.  l  is  a  cylinder  from  which  the  backcloth  is  unwoimd, 
being  first  stretched  by  the  roller,  n,  and  then  smoothed  by  the  scrimping  bars,  13,  from 
which  it  proceeds  to  join  the  blanket  on  arriving  at  the  roller,  k.  m,  a  roller,  from  which 
the  fabric  to  be  printed  is  unrolled  by  the  movement  of  the  machine,  first  passing  over  the 
scrimping  bars,  14,  and  joining  at  K  the  blanket  and  backcloth,  which  it  accompanies  in 
their  course  till  it  arrives  at  the  roller,  g,  when  it  separates  and  passes  off  in  the  direction 
of  the  line,  n,  to  the  hanging  rollers,  where  it  is  dried. 

The  machine  is  put  in  movement,  either  by  a  man  with  a  winch-handle,  or  by  power 
communicated  by  a  strap  which  passes  over  the  pulley,  18.  This  pulley  has  several 
diameters,  so  as  to  give  several  speeds ;  it  is  loose  on  the  driving  shaft,  and  carries  catches 


CALICO  PRINTING.  229 

which  lock  into  those  of  a  sliding  catch-box  on  the  shaft,  when  the  machine  is  to  be  put  in 
movement.  The  movement  of  the  machine  is  intermittent  because  the  printing  is  inter- 
mittent ;  moreover,  it  must  be  so  regulated  that  the  fabric  advances  a  distance  exactly 
equal  to  the  breadth  of  the  blocks,  and  that  it  moves  forward  whilst  the  sieves  are  charged 
with  color  from  the  rollers  8  8.  Tliis  result  is  obtained  by  means  of  a  regulator,  or  dividing 
wheel  20.  The  wheels  21,  fixed  at  the  extremities  of  the  axis  of  the  cylinders  1,  and 
havin"'  each  the  same  number  of  teeth,  receive  their  movement  from  a  central  wheel  toothed 
in  the  same  manner,  and  placed  behind  the  wheel  20.  This  last  receives  an  alternating 
motion  from  a  rack,  24,  fixed  in  a  copper  piece,  25,  and  which  rises  and  falls  alternately, 
beino-  keyed  at  its  lower  end  to  one  of  the  spokes  of  the  wheel  28.  By  varying  the  position 
of  the  point  at  which  the  end  of  the  rack  is  connected  with  the  spoke  26,  the  length  or 
ran^e  of  its  movement  is  proportionally  changed,  and  more  or  less  of  the  teeth  of  the  wheel 
20,°are  made  to  pass,  which  renders  proportionally,  greater  or  less,  the  advance  of  the  cloth 
at  each  movement ;  and  this  is  farther  regulated  by  a  ratchet  wheel  placed  at  d.  At  each 
half  turn  of  this  last,  the  lever  22  raises  the  catch  or  pallet,  and  throws  out  of  gear  the 
wheels  21  during  the  other  half  turn  ;  but  as  iu  the  working  of  these  wheels  there  would  be 
inevitably  a  backward  movement,  this  is  prevented  by  a  brake,  consisting  of  a  pulley, 
mounted  on  the  shaft  of  the  axis  of  the  wheel  20,  and  a  brass  wire,  which,  after  making  a 
turn  and  a  half,  or  two  turns,  on  this  shaft,  is  stretched  by  the  weight  23,  which  offers  a 
sufficient  resistance  to  any  recoil.  The  slides  or  block-holders  are  put  in  motion  by  the 
wheels  27  and  28,  gearing  with  the  larger  wheel  29.  And  to  vary  tlieir  action  at  pleasure, 
both  for  causing  the  blocks  to  bear  more  or  less  strongly  on  the  sieves,  so  as  to  be  more  or 
less  charged  with  color,  and  likewise  for  attaining  the  exact  pressure,  which  suits  best  for 
the  color  to  be  laid  on,  it  is  sufficient  to  move  the  points  of  junction,  IG  and  17,  to  a  greater 
or  less  distance  from  the  point  marked  15,  which  constitutes  the  centre  of  oscillation  of  the 
beams  that  work  the  slides.  The  movement  of  the  sieves  is  controlled  by  that  of  the  cam 
11,  30,  which  works  them  all  three  by  putting  in  motion  a  shaft  with  which  they  are 
respectively  keyed.  The  furnishing  rollers  receive  their  movement  from  gearing  with 
pinions  on  the  axes  of  the  rollers  8  8.  The  general  working  of  this  complex  machine 
remains  to  be  described.  When  put  into  regular  motion,  and  the  three  blocks  have  deliv- 
ered their  impression  exactly  at  the  same  instant,  three  simultaneous  movements  then  com- 
mence. 

1st.  The  stuff  advances  a  distance  exactly  equal  to  the  breadth  of  the  blocks,  and  with 
it  the  blanket  and  backcloth,  so  that  the  portion  of  the  fabric  which  leaves  the  third  block 
behind  it,  is  fully  printed  ;  that  which  was  under  the  second  advances  opposite  the  third  ; 
that  which  was  under  the  first,  moves  along  to  the  second  ;  and  a  fresh  breadth  of  white  or 
imprinted  fabric  arrives  opposite  the  first.  2d.  While  the  cloth  is  advancing  as  above 
stated,  the  sieves  take  the  place  which  they  occupy  in  the  section,  fi/j.  98,  that  is  to  say,  the 
first  on  the  right  hand  rises,  the  second  moves  from  left  to  right,  the  third  descends,  and  in 
this  movement  all  three  press  slightly  on  the  furnishing  rollers  8,  from  which  they  receive 
the  color,  which  has  been  spread  uniformly  by  the  brushes  9.  3d.  In  the  mean  time,  the 
slides,  or  blockholders,  by  a  forward  movement,  push  the  blocks  against  the  sieves,  to  charge 
them  with  color,  and  the  blocks,  at  the  same  time,  receive  from  the  slides  a  gentle  back- 
ward movement,  during  which  the  sieves  deviate  from  their  position  ;  the  blocks  then  return 
upon  them,  and  are  drawn  back  again  after  being  applied  to  a  new  part  of  the  color  sur- 
f\ice.  When  these  simultaneous  movements  have  taken  place,  the  action  of  the  machine 
proceeding  without  intermission,  the  sieves  move  back  from  before  the  blocks,  and  these  are 
j)ushed  up  against  the  latter,  printing  the  position  of  the  fabric  that  is  stretched  upon  them. 
Tills  brings  the  machine  to  that  position  at  which  the  description  commenced ;  and  this  suc- 
cession of  movements  is  renewed  and  repeated  as  long  as  the  operation  lasts ;  the  printer 
having  it  always  in  his  power  to  suspend  the  advance  of  the  stuff  whilst  the  working  of  the 
blocks  and  sieves  continues,  so  that  the  color  may  be  reappUed  to  the  same  part  of  the  fabric 
as  often  as  may  be  required  for  a  good  impression. 

There  have  been  several  attempts  at  block-printing  by  machinery  in  this  country,  amongst 
which  the  machines  of  Mr.  Joseph  Burch  have  been  most  successful ;  but  from  one  cause  or 
another,  none  of  them  have  ever  come  into  general  use,  and  it  is  unnecessary,  therefore,  to 
particularize  them. 

Before  proceeding  to  describe  the  more  complex  machines  which  print  upon  cloth  several 
colors  at  one  operation,  by  the  rotation  of  so  many  cylinders  or  rollers,  it  is  advisable  to 
give  some  insight  into  the  modern  method  of  engraving  the  copper  cylinders.  These  were 
formerly  engraved  altogether  by  hand,  in  the  same  manner,  and  with  similar  tools,  as  the 
ordinary  copper-plate  engravings,  till  the  happy  invention  of  Mr.  Jacob  Perkins,  of  America, 
for  transferring  engravings  from  one  surface  to  another  l)y  means  of  steel  roller  dies,  was 
with  great  judgment  applied  by  Mr.  Lockett  to  calico-printing,  so  long  ago  as  the  year  1808, 
before  the  first  inventor  came  to  Europe  with  the  plan.  The  pattern  is  first  reduced  or 
increased  in  size  to  such  a  scale,  that  it  will  repeat  eveidy  over  the  roller  to  be  engraved  ; 
and  as  rollers  are  of  varying  diameters,  owing  to  old  patterns  being  turned  off,  &c.,  this 


230 


CALICO  PRINTING. 


drawing  to  scale  has  to  be  adopted  for  every  roller,  the  exact  circumference  of  the  roller 
being  taken  and  the  pattern  arranged  in  accordance  with  this.  This  pattern  is  next  engraved 
in  intaglio  on  a  roller  of  softened  steel,  which  is  of  such  a  size  that  one  repeat  of  the  pattern 
exactly  covers  its  surface  ;  generally  these  rollers  are  about  3  inches  long,  and  from  ^  an 
inch  to  2  or  3  inches  in  diameter.  The  engraver  aids  his  eye  with  a  lens  when  employed 
at  this  delicate  work.  This  roller  is  hardened  by  heating  it  to  a  cherry-red  in  an  iron  case 
containing  pounded  bone-ash,  and  then  plunging  it  into  cold  water :  its  surface  being  pro- 
tected from  oxidizement  by  a  chalky  paste.  This  hardened  roller  is  put  into  a  press  of  a 
peculiar  construction,  called  the  clamming  machine,  where,  by  a  rotatory  pressure,  it  trans- 
fers its  designs  to  a  similar  roller  in  the  soft  state  ;  and  as  the  former  was  in  intaglio,  the 
latter  must  be  in  relievo.  This  second  roller  being  hardened,  and  placed  in  the  engraving 
machine,  is  employed  to  engrave  by  indentation  upon  the  full-sized  copper  cylinder  the 
whole  of  its  intended  pattern.  The  first  roller  engraved  by  hand  is  called  the  die  ;  the  sec- 
ond, obtained  from  it  by  a  process  like  that  of  a  milling  tool,  is  called  the  mill.  By  this 
indentation  and  multiplication  system,  an  engraved  cylinder  may  be  had  for  £1,  which  en- 
graved by  hand  would  cost  £5.  The  restoration  of  a  worn-out  cylinder  becomes  extremely 
easy  in  this  way ;  the  mill  being  preserved,  need  merely  be  properly  rolled  over  the  copper 
surface  again.  The  die  roller  is  made  of  such  a  size  that  its  circumference  is  exactly  a  frac- 
tional part  of  that  of  the  mills,  say  one-half,  one-third,  one-fourth  ;  then  in  the  clamming 

machine  the  die  revolving  in  contact 
with  the  mill  repeats  its  surface  so 
many  times  on  the  surface  of  the  mill. 
By  this  means  as  little  skilled  labor  as 
possible  is  used.  When  a  pattern 
having  more  than  one  color  is  to  be 
engraved,  the  drawing  is  reduced  to 
scale  as  before,  each  roller  being  made 
of  the  same  diameter ;  then  a  tracing 
is  made  of  each  color,  which  is  en- 
graved on  a  separate  die  and  mill — a 
mill  being  required  for  each  color — 
which  engraves  its  separate  copper 
color ;  when  these  rollers  come  to  be 
worked  in  the  printing  machine,  each 
roller  fits  its  part  of  the  pattern  into 
place,  and  the  original  pattern  is  re- 
produced. The  annexed  drawings  of 
engraving  machinery  are  from  those 
made  by  Messrs.  Gadd  and  Hill,  of 
Manchester,  to  whose  courtesy  are 
due  also  the  drawings  of  the  printing 
machines  and  their  drying  apparatus 
hereafter  described.  J'lff.  100  is  a 
front  view  of  the  clamming  machine, 
iiVidfc).  101  is  a  side  view  of  the  same. 
A  A  cast-iron  framework  ;  b  a  head- 
stock  screwed  on  the  framework  a  ;  c 
a  sliding  piece,  capable  of  movement 
from  back  to  front  on  the  headstock 
B  ;  the  position  being  determined,  it  is 
secured  by  the  screw  shown  under  c  ; 
the  roller  d  revolves  in  bearing  .attached 
to  the  sliding  piece  c  ;  the  supporting 
piece  E  has  a  motion  backwards  and 
forwards  on  the  supporting  piece  o, 
which  moves  up  or  down  ;  c  is  a  small 
sfecl  roller,  which  again  supports  the 
die  roller  seen  in  the  centre  of  the 
drawing.  The  roller  f  is  of  softened 
steel,  called  the  mill,  which  revolves  in 
bearings  attached  to  the  headstock, 
which  has  a  sliding  movement  on  the 
slide  block  n,  which  is  moved  from 
right  to  left  by  the  screw,  i,  worked 
by  the  lever  k.  l  is  a  pinion  gearing 
into  the  toothed  wheel  n,  and  turned  l)y  the  winch  handle  M  ;  the  shaft  p  has  a  sliding 
movement  through  the  wheel  n,  and  carries  the  boss  o,  which  has  a  square  aperture  to 


CALICO  FEINTING. 


231 


receive  the  centre  of  the  mill,  which  is  squared  to  fit  into  it.  y  is  a  screw  used  to  tighten 
and  keep  in  the  desired  position  the  saddle  pieces  e  o,  which  together  are  pushed  up  or 
down  to  meet  the  varying  size  of  the  die. 

The  die  d  having  been  hardened,  is  inserted  in  the  machine  resting  on  the  auxiliary  hard 
steel  roller  e,  which  again  rests  on  the  supporting'  piece  e  ;  the  die  being  in  contact  with 
the  hard  steel  roller  d,  the  soft  steel  roller  or  mill  e  is  next  forcibly  screwed  up  in  contact 
with  the  die,  rotatory  motion  being  given  to  the  roller  d  by  the  toothed  wheels ;  those  por- 
tions which  are  in  intaglio  in  the  die  become  in  relief  on  the  mill.  It  is  then  ready  for  the 
machine  engraver  to  transfer  its  pattern  to  the  copper  roller.     Fig.  102  is  an  elevation  of 


the  engraving  machine  a  a  is  a  mandrel  which  carries  the  copper  roller  b  ;  the  mandrel 
IS  fatted  in  the  universal  joint  c,  which  is  secured  on  the  shaft  of  the  wheels  i  d,  which  are 
a  double  pair  of  wheels  for  the  purpose  of  altering  the  speed  from  fast  to  slow,  and  are 
moved  by  the  winch  handle  or  pulley.  The  lever  e  is  fitted,  works  loosely  on  the  shaft  on 
which  13  keyed  the  wheel  f.  By  means  of  the  screw  g,  the  lever  e  can  be  secured  to'the 
wheel  F.  By  this  contrivance  the  motion  termed  rocking  is  effected,  that  kind  of  motion 
being  required  when  the  pattern  repeats  at  great  intervals.  The  mill  works  in  bearin-s  at- 
tached to  the  pil  ar  and  carriage  h  h,  which  is  moved  from  right  to  left  by  the  screw^i  i  • 
t  le  mill  IS  forcibly  pressed  against  the  copper  roller  by  a  weighted  lever,  which  forces  down 
the  bearings  of  the  mill  in  the  pillar  h  ;  this  lever  cannot  be  shown  in  the  figure  but  is  at 
right  angles  to  the  roller.  The  mill  being  in  contact  with  the  copper  roller,  r°volves  with  it 
simultaneously  on  the  roller  being  moved  by  the  wheels  d  d  or  the  lever  e,  and  consequentlv 
impresses  or  engraves  its  pattern  on  the  copper  roller;  when  the  mill  has  traversed  the  cir- 
cumference, It  is  then  moved  to  its  next  relative  position  by  the  screw  i,  which  moves  the 
pillar  and  carnage  h  ;  the  exact  distance  the  mill  moves  is  determined^  by  an  index  on  the 
wheel  K,  which  IS  divided  mto  segments,  corresponding  with  the  number  of  repeats  laterally 
on  the  roller  The  apparatus  shown  at  l  is  used  occasionally  when  the  machine  is  employed 
for  tiirning  off  an  engraved  pattern,  which,  however,  is  generally  performed  in  a  slide  lathe 
and  is  unnecessary  further  to  describe  here.  ' 

Etching  by  nitric  acid  is  largely  employed  in  engraving  for  calico  printing,  the  following 
being  the  process  :-The  copper  roller  is  first  coated  all  oler  with  a  thin  coating  of  bitumi" 
nous  varmsh,  and  when  dry  put  in  a  machine  which  rules  lines  about  the  V3.  of  an  inch 
apart  all  over  the  surface,  the  lines  all  running  in  one  direction  and  diagonally  to  the  axis 
the  varnish  being  cut  through  by  the  ruling  point.  The  pattern  is  then  traced  on  in  the 
usual  manner.  All  the  parts  that  are  intended  to  be  blank,  are  then  painted  in  with  the 
b.  iiminous  varnish  by  hand  ;  generally  the  outlines  are  put  in  bv  skilled  operatives  the 
failing-in  being  done  by  girls  or  boys;  when  dry,  the  roller  is  immersed  horizontallv  in  a 
bath  ot  diluted  mtnc  acid,  and  kept  there  for  a  few  minutes,  during  which  time  the  ac-id  at- 
tacks and  deepens  the  lines  which  are  unprotected  by  varnish  ;  tlic  roller  is  then  removed 
well  washed  with  water,  and  the  varnish  removed  by  oil  of  turpentine ;  the  pattern  is  found 
etched  with  diagonal  bars,  which  in  a  good  engraving  should  be  nearly  level  with  the  blank 
parts  ot  the  roller,  the  interstices  being  sufficient  to  supply  the  color.  The  outlines  of  the 
pattern  are  generally  completed  with  the  graver.  This  mode  is  well  adapted  for  civin-  a 
deep  engraving,  which  is  necessary  for  printing  coarse  fabrics.  When  a  pattern  is  wwn 
down  It  IS  easy  to  renew  it,  by  simply  painting  up  the  blank  parts  and  etching  deeper  by 
nitric  acid.  "        *         -^ 


232  CALICO  FEINTING. 

In  1854,  William  Rigby  patented  a  mode  of  transferring  patterns  to  copper  rollers  by  a 
modification  of  the  pentagraph.  The  pattern  to  be  engraved  being  drawn  on  an  enlarged 
scale,  and  put  on  a  bed  curved  to  an  arc  of  a  circle,  a  tracer  being  then  moved  over  all  the 
lines  of  the  pattern  by  a  beautiful,  but  simple,  arrangement  cf  machinery,  a  tracer  executed, 
on  a  varnished  roller,  a  reduced  copy  of  the  pattern  on  the  circvdar  bed.  In  a  patent,  dated 
1st  January,  1867,  Rigby  introduced  an  improvement  whereby  any  number  of  tracers  could 
be  simultaneously  worked  on  the  roller,  by  the  simple  movement  of  the  tracer  on  the  pat- 
tern ;  thus  all  the  repeats  of  the  pattern  could  be  executed  at  once.  The  mctliod  is  becom- 
ing very  extensively  adopted,  and,  independent  of  several  large  printers  having  begun  en- 
graving on  this  system,  a  very  large  establishment,  "  The  Burlington  Engraving  Company," 
has  been  commenced  with  a  view  to  engrave  on  this  principle.  All  descriptions  of  engrav- 
ing cannot,  however,  be  done  on  this  plan.     The  process  is  the  following : — 

The  pattern  is  first  enlai-ged  to  five  times  its  size :  this  is  conveniently  done  by  the 
camera.  The  paper  pattern  being  put  in  the  camera,  an  enlarged  copy  is  thrown  on  a  table 
in  a  darkened  room,  and  is  tliere  easily  traced  on  paper.  It  is  then  transferred  to  a  thin 
zinc  plate,  and  this  plate  is  then  engraved  with  a  coarse  graver,  the  lines  of  the  engraving 
being  adapted  for  the  tracing  point  to  work  easily  in.  The  zinc  pattern,  if  of  a  two-  or 
more  colored  pattern,  is  colored  for  the  guidance  of  the  operative.  It  is  then  laid  on  the 
curved  bed  of  the  pentagraph  machine,  and  a  varnished  roller  being  mounted  in  the  machine, 
a  numl)er  of  tools,  corresponding  in  number  to  the  repeats  laterally,  and  carrying  diamond 
points,  are  placed  in  contact  with  the  roller.  The  operative  then  carries  the  tracer  suc- 
cessively into  all  the  lines  of  the  pattern,  a  lever  allowing  the  points  to  touch  the  roller 
only  when  necessary.  The  pattern  is  thus  traced  by  the  etching  points  on  the  roller  one- 
fifth  of  the  size  of  that  on  the  zinc  plate,  or  the  same  size  as  the  paper  drawing.  The  roller 
is  then  painted  and  etched  with  nitric  acid,  as  before  described.  A  reference  to  the  annexed 
engiavings  will  more  clearly  illustrate  this  system. 

In  fiffs.  103  and  104,  a  represents  the  cylinder  to  be  operated  upon ;  and  6,  the  bed  or 
table  for  the  reception  of  the  enlarged  pattern  or  original  device ;  c,  the  tracer,  which  is 
made  to  traverse  in  the  direction  of  the  arc  of  the  bed  or  table,  and  by  means  of  its  connec- 
tion with  the  carriage  h,  the  rail  d,  and  the  connecting  arms  e  e,  communicates  part  of  a 
revolution  to  the  bar  or  axis  /,  and  thence  to  the  cylinder  through  the  dies  g  g,  on  which 
the  cylinder  rests.  The  cylinder  being  thus  moved  in  a  rotary  direction,  will  receive  from 
the  tools  in  contact  with  it  diminished  copies  of  the  transverse  lines  which  may  have  been 
gone  over  by  the  tracer  on  the  enlarged  pattern  or  device.  The  tracer  c  being  connected 
with  the  carriage,  //,  which  travels  along  the  rail  d,  will,  in  passing  over  a  line  running 
longitudinally  witli  the  machine,  communicate  a  partial  revolution  to  the  wheel  I  by  means 
of  the  bands  of  steel  _;'  _/,  similar  to  watch  springs,  which  pass  under  and  over  the  small 
wheels  k  k,  and  are  passed  round  and  secured  to  the  large  wheel  I,  which  is  mounted  on 
the  vertical  shaft  ??;,  carrying  at  its  upper  end  the  small  drum  >«',  round  which  passes  the 
steel  band  «,  secured  at  each  end  to  the  pieces  o  o.  These  pieces  are  secured  by  bolts  or 
screws  to  the  sliding  frames  p,  to  which  the  upper  tool  bar  or  bars  q,  which  support  the 
graving,  drilling,  or  etching  tools  r  r  ?•,  are  fixed.  Thus  any  motion  of  the  large  wheel  I 
will  be  imparted  to  the  drum  m',  and  by  it  through  the  steel  band  n  to  the  sliding  frames 
p,  and  the  tool  bars  q,  and,  consequently,  to  the  tools  r,  thereby  transferring  to  the  cylin- 
der diminished  copies  of  any  lines  in  a  lateral  direction  that  may  be  gone  over  by  the  tracer. 
It  will  be  evident  that  the  result  of  the  simultaneous  action  or  compounding  of  the  two  mo- 
tions, by  passing  the  tracer  over  any  diagonal  or  curved  line,  will  be  the  production  of  a 
diminished  copy  of  such  diagonal  or  curved  line  by  each  of  the  tools,  s  is  a  treadle  with  a 
vertical  link  and  appropriate  leverage,  by  which  the  tools  may  be  brought  in  contact  with 
the  cylinder  when  required ;  t  t  are  counterbalance  weights  for  the  connecting  arms  e  e, 
lower  rail  d,  &c.  ;  u  and  v  represent  a  worm  and  wheel  for  the  purpose  of  giving  the  roller 
an  extra  partial  revolution  when  it  is  required  to  engrave  upon  a  different  portion  of  the 
circumference  of  the  cylinder ;  and  to  effect  a  similar  jmrpose  in  the  longitudinal  direc- 
tion, the  tool  bar  may  be  made  to  shift  in  its  sliding  frame  with  an  adjusting  screw  attached 
to  it,  by  means  of  which  any  degree  of  exactitude  in  the  setting  of  the  tools  may  be  ob- 
tained. 

In  the  machine,  as  shown  in  the  accompanying  drawings,  the  design  executed  on  the 
cylinder  would  bear  the  same  proportion  in  size  to  the  enlarged  pattern  on  the  bed  or  table 
that  the  small  drum  m'  bears  to  the  large  wheel  I,  and  the  radius  of  the  disks  g  g,  to  the 
radius  of  the  circular  bed  ;  but  by  the  adaptation  of  wheels  and  disks  of  different  diameters, 
any  desired  proportion  between  the  pattern  engraved  and  the  enlarged  pattern  may  be 
adopted. 

In  fg.  103,  representing  a  mode  of  giving  an  alternate  reverse  action  to  the  tools  and 
bars  a',  are  the  bars,  to  one  of  which  a  longitudinal  to-and-fro  motion  is  given,  and  a  reverse 
motion  given  at  the  same  time  to  the  other  bar  by  means  of  the  links  or  rods  b\  connected 
to  the  beam  or  lever  c',  working  on  the  pin  or  fulcrum  d'  attached  to  the  framing  e'.  This 
arrangement  of  the  machine  is  suitable  for  turnover  patterns. 


CALICO  PRINTING. 

103 


233 


r 


■^m^mm^mim^^xi^y^^^^^^ 


K 


/^ 


-s 


234 


CALICO  PRINTING. 


105 


r©=i 


1 


•a' 


I^ 


']\o)el 


In  fffs.  106  and  107  the  tool  holders  are  adapted  for  employing  two  or  more  rows  of 
tools,  the  members  of  the  two  rows  being  placed  in  alternate  holders,  or  otherwise,  accord- 
ing to  the  pattern.  It  is  evident  that  by  slight  modifications  in  the  form  of  the  tool  holders 
the  tools  may  be  made  to  occupy  any  position  on  the  surface  of  the  cylinder,  thus  affording 
great  facility  for  placing  the  tools  and  making  them  applicable  for  step  patterns  or  other 
suitable  sketches. 

Figx.  106  and  107  show  two  such  modifications,  in  which/'  is  the  copper  roller ;  r/'  the 
line  of  fulcrums  or  centres  upon  which  the  tool  holders  h'  and  k'  vibrate,  the  said  tool 
holders  with  their  tools  being  lifted  off  by  the  cam  I',  and  advanced  to  their  work  by  the 
weights  ?«',  which  can  be  adjusted  with  any  required  nicety. 

^^Jlff^-  108  and  109  is  shown  another  arrangement  of  tools  with  swivel  bars,  the  swivel 
bars  being  shown  at  p',  and  placed  and  held  in  the  desired  position  by  the  screws  g'.  To 
the  bar  is  attached  the  carriage  r,  to  one  end  of  which  is  connected  the  tool  holder  s',  in 
which  is  a  projection  t',  acted  upon  by  a  beam  or  lever  ti  working  on  a  fulcrum  in  the  car- 
riage r .  The  tool  is  Hfted  off  the  roller  v'  by  means  of  the  cam  w',  and  returned  to  its 
work  by  means  of  a  spring  or  Indian-rubber  band  x\  attached  to  the  slide  r'.  It  will  be 
perceived  that,  independently  of  the  slot  or  slide  in  the  tool  holder,  great  change  of  position 
is  ol)tained  by  simply  shifting  the  carriages  longitudinally. 

The  "eccentric  engraving,"  or  etching,  of  Mr.  Lockett,  of  Manchester,  produces  on  a 
varnished  roller  the  most  curious  variety  of  configurations,  by  means  of  diamond  points, 
moved  by  very  elaborate  machinery,  the  patterns  being  the  result  of  eccentric  movements 
given  to  the  tracer  by  a  combination  of  machinery.  In  this  case  the  exact  effect  that  will 
be  produced  by  any  given  modification  of  the  niachine  cannot  be  determined,  though  an 
approximation  can  be  made  ;  but  when  a  pattern  is  produced,  and  notes  taken  of  the  rela- 
tive positions  of  the  wheels,  kc,  the  same  pattern  can  at  any  time  be  reproduced.  This 
system  is  applicable  principally  to  groundworks,  or,  as  they  are  termed,  "  covers."  It  is 
impossible  in  the  scope  of  this  article,  to  give  a  clear  idea  of  this  machine,  as  a  very  elabo- 
rate set  of  drawings  would  be  required. 

With  regard  to  the  2  and  3-colored  machines,  we  mu.st  observe,  that  as  the  calico  in 
passing  between  the  cylinders  is  stretched  laterally  from  the  central  line  of  the  web,  the 
figures  engraved  upon  the  cylinders  must  be  proportionally  shortened,  in  their  lateral  di- 
mensions, especially  for  the  first  and  second  cylinder. 


CALICO  PRINTING. 


235 


Cylinder  printing,  although  a  Scotch  invention,  has  received  its  wonderful  development 
in  England,  and  does  the  greatest  honor  to  this  country.  The  economy  of  labor  introduced 
by  these  machines  is  truly  marvellous ;  one  of  them,  under  the  guidance  of  a  man,  to  regu- 
late the  rollers,  and  the  service  of  two  boys,  to  supply  the  color  troughs,  &c.,  being  capable 
of  printing  as  many  pieces  as  nearly  200  men  and  boys  could  do  with  blocks. 

In  mounting  two  or  more  cylinders  in  one  frame,  several  adjustments  become  necessary. 
The  first  and  most  important  is  that  which  insures  the  correspondence  between  the  parts  of 
the  figures  in  the  successive  printing  rollers,  for  unless  those  of  the  second  and  subsequent 
engraved  cylinders  be  accurately  inserted  into  their  respective  places,  a  confused  pattern 
would  be  produced  upon  the  cloth  as  it  advances  round  the  pressure  cylinder. 

Each  cylinder  must  have  a  forward  adjustment  in  the  direction  of  rotation  round  its  axis, 
so  as  to  bring  the  patterns  into  correspondence  with  each  other  in  the  length  of  the  piece  ; 
and  also  a  lateral  or  traverse  adjustment  in  the  line  of  its  axis,  to  effect  the  correspondence 
of  the  figures  across  the  piece  ;  and  thus,  by  both  together,  each  cylinder  may  be  made  to 
work  symmetrically  with  its  fellows. 


110 


Fig.  110  is  an  end  elevation  of  a  4-color  printing  machine,  and  fig.  Ill  is  a  section  of 
same  :  the  same  letters  of  reference  refer  to  both,  a  is  the  cast-iron  framework,  bolted  to 
a  corresponding  framework  by  the  bolts  b,  with  a  space  of  from  3  to  4  feet  between  ;  c  is 
the  pressure  cylinder,  about  2  feet  diameter,  of  iron,  but  hollow,  and  between  3  and  4  feet 
long,  according  to  the  sort  of  cloth  the  machine  is  intended  to  print ;  d  are  the  copper  roll- 
ers, the  width  of  a  piece  of  cloth  ;  e  are  wrought-iron  mandrels,  on  which  the  copper  roller 
is  forced  by  a  screw  press,  the  mandrel  being  about  4  inches  diameter  where  the  roller  fits 
on,  but  with  journals  of  smaller  diameter.  Tiie  roller  is  made  with  a  projecting  piece  insi<le, 
about  \  an  inch  broad,  and  J  of  an  inch  deep,  extending  all  the  width  of  the  roller ;  this 
tab,  as  it  is  called,  fits  in  a  slot  cut  in  the  mandrel,  which  causes  it  to  turn  without  slipping 
on  the  mandrel ;  the  pressure  cylinder  or  bowl  c,  rests  with  its  gudgeons  in  bearings  or 
bushes,  which  can  be  shifted  up  and  down  in  slots  of  the  side  cheeks  a  ;  these  bushes  are 
suspended  from  powerful  screws  f,  which  turn  in  brass  nuts  made  fast  to  the  frame  a. 
These  screws  counteract  the  pressure  upwards  of  tlie  two  lowest  rollers,  and  enable  the  bowl 
to  be  lifted  out  of  the  way  of  the  rollers,  &c.,  when  they  have  to  be  removed,  o  o  are 
sliding  pieces,  moving  in  arms  of  the  framework,  by  means  of  screws  n  n.  These  sliding 
pieces  carry  the  bearings  of  the  mandrels ;  to  them  are  also  attached  the  color  boxes  and 
doctors.  The  screws  ii'  work  in  female  screws  i',  which  form  part  of  a  system  of  jointed 
levers  k.  These  levers  are  for  the  purpose  of  giving  an  additional  pressure  or  nip  to  the 
rollers  D,  the  pressure  being  also  elastic.  There  are  ibur  j)airs  of  levers,  each  pair  bearing 
upon  one  mandrel.  It  will  l)e  sufficient  to  describe  one  siile  orily,  l)oth  sides  l)eing  precisely 
alike.  The  two  highest  rollers  are  jiressed  against  the  cylintler  liy  the  compound  levers  k', 
which  have  attachments  to  the  anns  of  the  framework  at  /",  and  to  the  inside  of  the  main 
framework  at  g  and  m'  as  fulcrums,  and  are  jointeil  together  at  /(  //,  but  the  bent  levers  //, 
g,  i,  merely  fit  into  sockets  /,  of  tlic  horizontal  levers  m'  k',  which  are  weighted  at  the 
ends,  k',  by  movable  weights  made  to  fit  expanded  parts.    The  two  lowest  rollers  are  pressed 


236 


CALICO  PRmXIKG. 
Ill 


against  the  cylinder  by  the  system  of  compound  levers  k",  which  have  attachments  to  the 
framework  at  k  and  m"  as  fulcrums ;  the  screws  h"  h"  worliing  in  female  screws  i"  i", 
as  in  the  other  set  of  levers.  For  convenience  of  removing  the  rollers,  color  boxes,  &c., 
these  levers  are  provided  with  a  hinged  piece  n,  in  a  socket  o,  on  the  top  of  which  work 
the  screws  1 1,  which,  by  means  of  the  female  screw  in  the  lever  k  k",  serve  still  further  to 
regulate  the  pressure  ;  the  lever  k"  k  is  shown  as  when  the  machine  is  printing ;  but  when 
the  rollers,  &c.,  are  to  be  removed,  the  lever  is  lifted  by  the  handle,  and  the  hinged  piece  N 
pulled  over,  the  lever  with  its  burden  being  then  lowered  down ;  the  weighting  of  these 
levers,  which  are  partly  outside  the  machine,  is  best  seen  in  Jjc/s.  110  and  111,  where  l  are 
the  weights,  q  are  color  boxes,  the  sides  and  bottom  of  which  are  made  of  sheet  copper,  and 
the  ends  of  gun-metal ;  in  each  end  is  a  slot,  which  receives  the  brass  journals  of  the 
wooden  furnishing  rollers  p,  which  are  wrapped  with  a  few  folds  of  coarse  calico,  and,  by 
revolving  in  the  color  and  against  the  engraved  rollers  d,  supply  it  equally  all  over  with  the 
color  ;  the  superfluous  color  is  next  wiped  off  by  the  color  doctors  t.  These  doctors  are 
thin  plates  of  steel  or  brass,  which  are  mounted  in  doctor  shears,  or  plates  of  metal  screwed 
together  with  bolts  ;  the  shears  have  journals  which  rest  in  bearings  movable  backwards  and 
forwards  by  the  screws  s  ;  the  doctors  are  kept  in  close  contact  with  the  engraved  roller  by 
levers  and  weights,  for  the  way  of  arranging  which,  see  ^fig.  112,  where  a,  b,  c,  are  the 
levers  attached  to  the  doctor  shears.  On  the  ends  of  these  levers  weights  are  hung,  and 
by  this  means  the  doctors  are  pressed  forcibly  against  the  roller. 

After  printing  the  pattern  on  the  piece,  the  roller  d  is  cleaned  from  threads  or  dust  by 
the  lint  doctors  r,  pressed  against  the  roller  by  the  screws  s,  Jif/.  Ill  ;  any  loose  threads 
from  the  piece  are  prevented  by  tlie  lint  doctors  from  going  into  the  color,  and  consequently 
under  the  cleaning  doctors,  where,  by  preventing  them  from  perfectly  wiping  the  blank 
parts  of  the  roller,  smears  on  the  piece  would  ensue.  The  color  boxes  are  mounted  on 
wooden  boards,  to  give  them  greater  strength,  and  are  tiglitcned  up  against  the  roller,  by 
the  screws  r  r  and  w  w  ;  the  lower  pair  of  color  boxes  are  removed  from  the  copper  roller 
when  not  in  use  by  the  handles  v,  after  detaching  the  screws  w  w.  There  is  a  toothed 
wheel  slipped  on  to  each  mandrel,  working  into  a  toothed  wheel  on  the  axis  of  the  furnish- 
ing roller,  which  ensures  the  copper  roller  and  furnishing  roller  always  turning  together. 
By  means  of  an  eccentric,  fixed  on  the  axis  of  the  pressure  bowl,  and  connected  with  each 
cleaning  doctor,  a  regular  vibratory  movement  is  given  to  them,  which  prevents  the  doctor 
being  worn  down  unequally.  Sometimes  for  the  highest  rollers,  and  especially  in  machines 
of  more  than  four  colors,  the  cumbrous  color  box  is  dispensed  with,  and  a  doctor  inserted 
in  a  curved  frame  is  applied  to  the  roller  instead.  In  this  arrangement  the  doctor  forms 
the  bottom  of  the  color  reservoir,  and  is  pressed  strongly  against  the  roller ;  the  curved  frame 
stopped  off  at  the  sides  with  a  piece  of  copper  curved  to  fit  both  roller  and  frame,  and  which 


CALICO  PRINTING. 


237 


is  padded  with  a  piece  of  folded  cotton  cloth,  forms  the  color  box.  This  doctor  box  takes 
but  little  room,  and  wastes  but  little  color,  but  is  only  used  for  the  uppermost  rollers. 
Neither  of  these  arrangements  can  be  shown  in  fig.  111.  The  roll  of  pieces  is  shown  at  «, 
wound  on  the  wooden  roller  6,  the  axis  of  which  Vests  in  bearings  at  the  end  of  the  arms. 
The  piece  is  conducted  under  a  small  wooden  roller,  next  over  a  square  iron  bar,  and  next 
against  the  scrimping  bar  y,  thence  over  the  wooden  roller  x,  round  which  also  pass  the 
gray  piece  (/,  and  the  woollen  blanket  e.     The  scrimping  bar  is  a  bar  of  iron  or  brass,  with 


curved  surface,  furrowed  by  grooves,  cut  right  and  left  from  the  centre.    See  Calico  Print- 
ing, vol.  i.    In  passing  over  this  bar,  the  cloth  is  stretched  equally  from  the  centre,  and  any 


238 


CALICO  FEINTING. 


lU 


folds  or  creases  removed.  In  order  that  the  piece  may  be  constantly  stretched,  the  roller  b 
is  provided  with  a  wooden  pulley,  round  which  passes  a  leather  strap,  one  end  of  which  is 
made  fast  to  the  framework,  and  to  the  other  is  attached  a  weight ;  the  friction  of  the  strap 
against  the  pulley  causes  a  retarding  action  of  the  piece,  and  consequently  keeps  it 
stretched. 

Fi(j.  113  is  an  elevation  of  a  12-color  machine,  which  is  inserted  to  show  the  way  in 
which  all  machines  are  driven.  The  lai-ge  spur  wheel  is  kej'cd  on  the  axis  of  the  pressure 
howl,  and  works  into  pinions  staked  on  the  mandrels ;  there  is  a  peculiarity  about  these 
pinions,  or  box  wheels,  as  they  are  called,  which  may  be  observed  in  fg.  113,  but  is  shown 
on  an  enlarged  scale  in  Jig.  114,  which  is  a  box  wheel  detached.  This  wheel  may  be  com- 
pared to  the  fine  adjustment  of  a  micro- 
scope, as  by  means  of  it  the  rollers  receive 
the  final  and  delicate  adjustment  so  as  to  reg- 
ister accurately  with  one  another.  It  consists 
essentially  of  two  parts  :  the  disk  a,  carrying 
the  cogs  ;  and  the  hollow  axis  b,  carrying  a  disk 
at  one  side,  and  the  connecting  piece  and 
screw  c  D  at  the  other.  The  part  a  a,  or  shell 
of  the  wheel,  is  about  10  inches  diameter  and 
3  inches  broad  across  the  cogs ;  one  side  of 
the  shell  is  cut  out  to  receive  the  plate  shown 
by  dotted  lines.  This  plate  is  provided  with 
the  hollow  axis  b,  which  comes  through  the 
shell,  and  projects  about  3  inches,  the  part  pro- 
jecting being  cut  through  at  f  f  ;  fastened 
to  it  also  is  the  connecting  piece  c,  in  which 
works  the  screw  d  ;  this  screw  just  fits  in  two 
projecting  lugs  G  G,  cast  on  the  shell  a.  The 
screw  nut  e  forms  part  of  the  axle  piece,  and 
works  in  the  slide  h.  When  this  wheel  is 
used,  it  is  slipped  on  the  mandrel  which  carries  the  copper  roller,  and  a  cotter  is  driven 
through  the  cleft  axle  and  through  a  corresponding  cotter  hole  in  the  mandrel,  thus  firmly 
connecting  the  mandrel  and  wheel ;  the  mandrel  and  roller  being  put  in  their  place  in  the 
machine,  the  cogs  of  the  mandrel  wheel  work  into  the  main  driving  wheel,  as  shown  in  Jig. 
113.  The  coarse  adjustment  of  tl>e  rollers  being  made  when  putting  them  in  their  places, 
the  fine  adjustment  is  made  by  turning  the  screw  d.  It  is  obvious  that  the  screw  d,  by 
pressing  against  the  lugs  g  of  the  shell  a,  which  is  geared  into  the  driving  wheel,  will  turn 
the  mandrel  and  roller  without  moving  the  cogs.  By  this  arrangement,  any  roller  may  be 
moved  round  about  2  inches  at  any  time  after  being  fixed  in  its  place.  All  machines  of 
more  than  one  color  are  fitted  with  these  wheels,  which,  indeed,  are  indispensable. 

In  Jig.  113  is  also  shown  a  piece  of  apparatus  attached  to  the  framework  for  the  purpose 
of  cleaning  the  cloth  from  dust  and  threads  before  printing.  This  apparatus,  patented  by 
John  Coates,  of  Manchester,  is  shown  on  an  enlarged  scale  in  fg.  115.     It  consists  essen- 

115 


tially  of  a  brush  and  a  roller,  covered  with  card  or  the  wire  material  used  in  cotton-carding 
engines ;  these,  with  the  gearing,  are  attached  by  the  straps  of  iron  b  n  to  the  ends  of  the 
rods  A  A,  care  being  taken  that  the  roller  o  is  placed  parallel  to  the  printing  macliine,  and 
the  apparatus  sufficiently  high  to  be  over  the  liead  of  the  person  engaged  at  work  behind 
the  machine,  and  convenient  for  him  to  reach  out  the  roller  and  brush,  when  they  require 


CALICO  PRINTING. 


239 


cleaning.  The  piece  passes  over  the  small  roller  c,  whether  delivered  from  the  "  roll,"  or 
"  beam,"  as  at  n  or  o  ;  it  then  goes  under  the  wooden  rail  d,  and  over  a  brush  e,  and  after- 
wards, at  F,  it  comes  on  to  the  card  roller,  which  is  turned  by  the  plain  roller  g  (over  which 
the  piece  passes)  the  contrary  way  to  the  piece,  so  that  the  card  catches  any  loose  material, 
and  prevents  it  again  adhering  to  the  piece. 

Four  five,  and  si.K-color  machines,  similar  to  the  above,  are  now  at  work  in  many  estab- 
lishments in  Lancashire,  which  will  turn  off  a  piece  of  28  yards  per  minute,  each  of  the 
three  or  four  cylinders  applying  its  peculiar  part  of  the  pattern  to  the  cloth  as  it  passes  along 
by  ceaseless  rotation  of  the  unwearied  wheels.  At  this  rate,  the  astonishing  length  of  one 
niile  of  many-colored  web  is  printed  with  elegant  flowers  and  other  figures  in  an  hour. 
When  we  call  to  mind  how  much  knowledge  and  skill  are  involved  in  this  process,  we  may 
fairly  consider  it  as  the  greatest  achievement  of  chemical  and  mechanical  science. 

The  general  course  of  printing  is  thus  performed  : — The  pieces  to  be  printed  are  wound 
on  a  beam,  and,  last  of  all,  a  few  yards  of  common  coarse  cotton  or  calico,  kept  for  this 
purpose :  this  is  for  the  printer  to  fit  the  pattern  on,  to  save  good  cloth.  The  roll  of 
cloth  being  put  in  its  place  behind  the  machine,  the  printer's  assistant  stations  himself  be- 
hind to  guide  the  cloth  evenly,  and  pluck  off  any  loose  threads  he  may  see.  The  machine 
printer  stands  in  front,  and,  after  having  fitted  the  pattern  on  the  cloth,  attends  to  supplying 
the  color-boxes  with  color,  and  regulating  any  misfitting  or  inequality  in  the  printing.  The 
machine  then  prints  rapidly.  After  running  through  30  or  40  pieces,  the  printer  stops  the 
machine,  removes  the  doctors,  and  files  them  anew  to  a  bevelled  sharp  edge. 

To  prevent  the  blanket  being  too  soon  soiled,  it  is  usual  to  run  gray  or  unbleached 
pieces  between  the  blanket  and  the  white  pieces.  The  blanket,  gray,  and  printed  pieces 
are  dried  separately.     There  are  several  ways  of  drying  after  the  machine.    Ihefcf.  116 

116 


may  be  taken  as  representing  a  good  and  effective  method.  Behind  the  printing  machines 
there  is  a  hot  room,  in  which  is  fixed  the  bulk  of  the  drying  apparatus.  This  room  is  kept 
closed,  and  is  ventilated  so  as  to  let  out  the  steam,  &c.  ;  it  is  of  necessity  of  much  higher 
temperature  than  the  printing  apartment.  Above  the  printing  machine  is  fixed  a  frame- 
work, which  carries  the  supports  for  the  rolls  of  gray  pieces,  and  a  long  range  of  steam 
chests,  a  a.  These  steam  chests  are  the  .same  width  as  the  machine,  about  1  foot  broad 
and  3  or  4  inches  deep,  and  are  connected  one  with  another  Ijy  bent  pipes  at  the  end.  The 
range  of  steam  chests  is  continued  through  an  aperture  in  the  wall  into  the  hot  room,  and 
below  them  is  an  arrangement  of  steam  cylinders,  turning  on  hollow  axes,  through  which 
steam  is  admitted.  The  course  of  the  blanket,  gray,  and  piece,  will  be  seen  on  reference  to 
fiff.  116,  in  which  the  shortest  arrow  shows  the  course  of  the  blanket,  the  longest  arrow  the 
course  of  the  printed  pieces,  and  the  middle-sized  one  that  of  the  gray  pieces.  The  wliite 
pieces  leave  the  roll  6,  passing  over  a  wooden  roller,  and  thence  round  the  cylinder  along 
with  the  gray  and  the  blanket.  After  receiving  the  impression,  the  piece  passes  over  a 
small  roller  at  the  edge  of  the  framework,  and  thence  along  the  top  of  the  steam  chests, 
the  roller  being  so  regulated  as  to  keep  the  pieces  close  to  the  chests,  but  not  touching 
them.  It  passes  along  the  straight  length  and  flown  the  incline  ;  on  leaving  the  chests,  it 
passes  round  the  cylinders  Nos.  6,  5,  and  4,  being  so  .stretched  by  rollers  as  to  embrace 
nearly  the  whole  of  the  cylinders  ;  it  then  passes  under  the  framework  and  up  through  an- 
other narrow  aperture  in  the  wall,  being  conducted  through  a  plni.fi iiij-doini  apparatus, 
which  has  drawing  rollers  at  tlie  end  of  a  pair  of  arms,  which  move  in  a  si'gment  oi'  ii  circle, 
and  so  fold  the  piece  backwards  and  forwards  in  a  loose  i)ilc.  The  gray  and  tlic  lilankct, 
on  leaving  the  cylinder,  proceed  together  over  a  roller  at  the  under  side  of  the  stciim  chests, 
along  which  they  travel  as  far  as  the  roller  r,  where  they  part  company,  the  l)lankt'ts  pass- 
ing dowii  over  the  cylinders  1  and  2,  thence  imder  these  cylinders  and  over  and  under  the 
rollers  d  d,  returning  along  under  the  steam  chests  rouiul  rollers  n  c,  and  go  again  into  the 
machine.  The  gray  pieces,  after  leaving  the  roller  c,  pa.ss  along  the  under  side  of  the  chests 


240 


CALICO  PKINTmC. 


to  the  roller/,  thence  round  the  cylmder  3,  the  rollers  g  g,  being  finally  wound  on  a  beam 
at  h.  When  the  roll  of  gray  pieces  i  is  exhausted,  the  roll  h  is  put  in  its  place,  the  gray 
piec^es  being  run  through  the  machine  two  or  three  times,  according  as  they  are  more  or  less 
stained,  and  then  sent  to  the  bleach  house. 

Scarcely  any  print  works  are  without  several  5  and  6-color  printing  machines,  and  the 
printers  of  goods  intended  for  hangings,  which  are  generally  of  elaborate  floral  designs,  em- 
ploy machines  capable  of  printing  from  10  to  20  colors  at  once.  These  machines  are  neces- 
sarily of  very  large  dimensions.     Fig.  117  is  an  end  view  of  a  20-color  machine,  made  by 


Messrs.  Gadd  and  Hill,  of  Manchester,  for  Mr.  Kay,  of  Castleton  Print  Works,  and  is  em- 
ployed in  printing  very  beautiful  floral  patterns  on  woollen  fabrics,  in  imitation  of  those 
produced  by  hand  labor  in  France. 

The  system  of  turning  cylinder  machines,  patented  by  Mr.  Joseph  Leese,  possesses 
several  advantages.  In  this  plan  a  small  high-pressure  oscillating  engine  is  attached 
directly  to  the  axis  of  the  large  cylinder,  thereby  dispensing  with  the  heavy  gearing  and 
shafting  required  when  machines  are  turned  by  a  large  stationary  engine  ;  the  machine  print- 
er also  has  perfect  command  over  the  speed  of  the  machine,  and  can  fit  the  pattern,  when 
it  is  turning  very  slowly,  with  more  convenience  than  on  the  usual  system.  On  this  system 
also  machines  can  be  put  down  in  any  portion  of  the  works,  and  are  independent  of  the  sta- 
tionary engine. 

In  surface  printing,  the  cylinder  or  roller  is  in  relief,  just  as  the  wooden  blocks  used  by 
hand,  and  the  manner  of  working  them  is  shown  in  fg.  118,  which  is  the  section  of  an  8- 
color  surface  machine  of  Gadd's.  a  a  is  the  framework  ;  b  b  the  bowl  or  cylinder,  which 
is  hollow,  and  made  with  arms  inside ;  c  c  are  the  surface  rollers,  supplied  with  color  by 
the  endless  web  or  sieve  //,  revolving  round  the  wooden  tension  rollers  d  d  e  ;  the  roller 
E  is  screwed  down  so  as  to  press  the  sieve  on  the  furnishing  roller  r,  which  revolves  in  the 
copper  color  box  g  ;  the  two  tension  rollers  next  to  the  surface  roller  move  in  slides,  so 
that,  by  means  of  the  screw  }i,  the  sieve  can  be  pressed  against  the  surface  roller ;  on  leav- 
ing the  furnishing  roller  f,  the  sieve  is  wiped  by  the  doctor  i,  screwed  lightly  against  the 
sieve  by  the  screw  k. 

The  printing  roller  being  in  relief,  there  is  no  necessity  for  the  complicated  arrangement 
of  levers  as  in  the  ordinary  machine,  and  consequently  the  surface  machine  is  much  more 
simple.  It  is  only  adapted  for  patterns  of  little  delicacy,  as  the  outlines  are  apt  to  be  not 
well  defined  ;  the  colors,  however,  from  being  laid  on  the  top  of  the  cloth,  are  very  rich, 
hence  for  woollen  fabrics  the  surface  machine  is  well  adapted. 


CALICO  PRINTING. 

118 


241 


Pieces  for  printing  by  machine  are  stitched  together  end  to  end,  -nhich  is  usually  done 
by  girls,  but  the  use  of  stitching  machines  is  rapidly  becoming  general,  and  probably  will 
soon  become  universal.     One  of  these  machines,  found  advantageous,  is  shown  in_^^.  119. 

119 


This  machine  was  the  invention  of  Charles  Morey,  in  1849.  A  pair  of  wheels  are  fitted 
with  leaves  on  their  peripheries,  and  gear  into  one  another  like  cog-wheels.  These  wheels 
are  mounted  in  suitable  bearings  fixed  to  a  sole  plate,  and  receive  rotary  motion  by  means 
of  a  winch-handle.  The  centre  of  the  teeth  of  both  wheels  is  cut  away,  so  as  to  form  a  cir- 
cular groove  between  the  two  teeth  which  happen  to  be  together.  Opposite  to  this  groove, 
and  attached  to  the  frame,  there  is  a  bracket  which  carries  ii  sliding  piece,  with  a  spiral 
spring  wrapped  around  it.  In  the  end  of  the  sliding  piece,  which  passes  through  the  bracket, 
there  is  a  receptacle  for  the  eye  end  of  a  needle,  the  point  of  which  rests  in  the  groove 
formed  by  the  wheel ;  the  needle  is  threaded,  and  the  fabric  to  be  stitched  placed  behind 
the  wheels,  to  which  rotary  motion  is  coninumicatcd,  whurcby  the  faljric  is  successively 
folded  into  undulations,  which,  as  the  operation  proceeds,  arc  forced  on  the  point  of  the 
needle  ;  when  the  needle  is  full,  and  the  piece  at  the  other  side  of  the  wheels,  the  needle  is 
Vol.  III.— 16 


242  CALICO  FEINTING. 

pushed  back  on  the  spring,  removed  from  the  machine,  and  the  thread  drawn  through  the 
pieces,  which  are  then  basted  or  stitched  together.  This  is  a  very  rapid  mode  of  stitching 
ends  of  pieces  together ;  but  where  a  number  of  pieces  are  stitched  end  to  end  for  the  pur- 
pose of  being  put  through  several  operations  without  unstitching,  a  firmer  description  of 
stitching  is  required,  and  a  machine,  known  as  the  American  machine,  and  patented  by 
Newton  in  1853,  is  frequently  used.  This  machine  consists  of  an  arrangement,  whereby  a 
bearded  needle  is  employed  for  throwing  a  line  of  looped  stitches  into  the  fabric.  The 
pieces  are  hung  double  on  pins  projecting  from  two  circular  racks,  which  move  in  grooves 
formed  in  the  face  of  a  circular  frame.  These  racks  are  driven  by  pinions  taking  into 
their  teeth,  and  thus  the  piece  ends  are  passed  under  the  action  of  the  needle,  which,  hav- 
ing a  quick  reciprocating  motion  similar  to  that  of  the  needles  of  stocking  frames,  and  being 
in  like  manner  supplied  with  thread,  is  passed  backwards  and  forwards  through  the  fabric, 
and  thereby  leaves  a  chain  of  loops  on  the  inner  face  thereof.  Carried  by  the  same  arm  is 
a  stiletto,  which  pierces  holes  in  the  fabric  to  allow  of  the  needle  passing  freely  through 
the  same.  The  machine  being  rather  elaborate,  will  be  described  in  the  article  Sewing 
Machines. 

Pieces  are  also  frequently  gummed  together  at  the  ends,  which  is  done  by  pasting  the 
ends  for  about  1^  inches  with  paste  or  gum,  and,  after  laying  one  on  the  other,  drying  them 
immediately  on  a  steam  pipe  in  front  of  the  operator.  This  mode  is  advantageous  for  some 
purposes,  as  when  the  pieces  come,  in  the  subsequent  operations,  into  hot  water,  they  are 
easily  detached  one  from  the  other. 

By  whichever  of  these  modes  the  pieces  arc  joined  together,  they  are  then  wound  in 
rolls  of  about  40  pieces  by  a  machine  called  a  candroy,  which  winds  them  on  the  wooden 
beam  which  fits  in  at  the  back  of  the  printing  machine  ;  the  cloth  during  the  operation  of 
winding  becomes  stretched  laterally  quite  smooth,  by  the  aid  of  one  or  two  grooved  stretch- 
ing bars,  a  due  degree  of  strain  being  kept  on  the  piece  by  it  passing  under  and  over  several 
plain  wooden  bars,  and  to  the  axis  of  the  wooden  beam  which  receives  the  pieces  being  sus- 
pended weights  which  keep  it  forcibly  in  contact  with  the  wooden  drum  which  turns  it  by 
friction.  In  this  machine,  the  ends  of  the  axis  of  the  beam  pass  through  slots,  which  allow 
it  to  rise  as  the  pieces  become  wound  on,  and  the  diameter  consequently  increases.  If  fewer 
pieces  than  40  are  to  be  printed  in  one  pattern  or  coloring,  it  is  usual  to  stitch  a  few  yards 
of  old  cloth  between  two  pieces  where  the  change  is  intended  to  be  made  ;  by  this  means 
the  printer,  on  coming  to  the  waste  piece,  stops  his  machine,  and  fits  another  pattern  or 
changes  the  colors  without  damaging  good  cloth. 

The  doctors  used  in  cleaning  off  the  superfluous  color  from  the  rollers,  are  generally 
thin  blades  of  steel,  of  a  thickness  varying  from  Vsa  of  an  inch  to  Vie  of  an  inch,  according 
to  the  sort  of  engraving  on  the  roller ;  but  some  colors,  such  as  those  containing  salts  of 
copper,  would  be  too  corrosive  on  a  steel  doctor,  and  in  this  case  doctors  of  a  composition 
like  brass  are  used.  They  arc  filed  to  a  bevelled  edge,  and  require  to  be  retouched  with 
the  file  after  printing  from  10  to  80  pieces.  The  cylinder  or  drum,  in  contact  with  which 
revolve  the  copper  rollers,  is  wrapped  round  with  a  cloth  called  "  lapping,"  which  is  gen- 
erally a  coarse  strong  woollen  cloth  of  peculiar  make,  and  is  folded  tight  on  the  cylinder 
about  ^  an  inch  thick.  The  blanket  is  next  put  on  and  drawn  tight :  this  blanket  is  a  very 
im])ortant  part  of  the  machine  ;  it  is  a  thick  woollen  web,  about  40  yards  long,  and  requires 
to  be  made  with  great  care,  so  as  to  be  uniforni  in  texture,  thickness,  and  elasticity.  If 
the  blanket  is  uneven,  it  has  the  efl'ect  of  throwing  the  blanket  into  confusion  at  the  un- 
even places. 

A  good  blanket  will  serve  to  print  10,000  pieces,  being  washed  whenever  loaded  with 
color,  and  then  is  suitable  for  covering  the  tables  of  the  block  printer. 

In  the  year  1835  Messrs.  Macintosh  and  Co.  patented  an  Indian-rubber  blanket,  which  con- 
sists of  several  thick  cotton  webs,  cemented  together  with  dissolved  Indian-rubber.  This  blan- 
ket is  very  useful  and  economical  for  some  purposes ;  the  surface  being  very  smooth,  great 
delicacy  of  impression  is  obtained,  and,  when  soiled,  it  is  not  necessary  to  remove  it  from  the 
machine,  as  it  is  easily  washed  with  a  brush  whilst  revolving  on  the  machine.  An  Indian- 
rubber  blanket  will  print  20,000  pieces,  which  is  twice  as  much  as  a  woollen  one  will  do,  the 
price  per  yard  being  also  lower.  Several  descriptions  of  these  blankets  are  made  by  Messrs. 
Macintosh,  some  of  them  having  a  coating  of  vulcanized  Indian  rubber  on  the  face  that  is 
printed  from,  thereby  giving  a  still  more  elastic  surface.  A  great  improvement  has  been 
recently  made  in  these  Indian-rubber  blankets  by  shrinking  or  preparing  the  cotton  pre- 
vious to  cementing,  according  to  the  patent  process  of  Mr.  John  Mercer,  viz.  by  soaking  in 
strong  alkali,  and  afterwards  in  dilute  sulphuric  acid  ;  this  process  contracts  the  fibre  to  a 
certain  extent,  and  the  cloth  is  found  to  jjossess  a  great  increase  of  strength.  When  made 
into  blankets,  they  arc  found  to  be  more  capable  of  resisting  the  severe  strains  of  the  print- 
ing process,  and  consecjuently  many  more  pieces  can  be  printed  from  them  than  from  the 
old  sort.  They  arc  made  by  Mr.  Kichard  Kay,  of  Accrington,  and  are  coming  into  general 
use.  The  woollen  blanket,  however,  seems  to  be  preferred  for  several  styles.  Several 
patents  have  been  taken  out  for  printing  without  blankets,  but  have  never  come  into 


CALICO  PRINTING.  24^ 

general  use  ;  but  recently  a  mode  of  printing  with  gray  or  unbleached  calico  has  come  into 
use,  which  is  very  favorably  spoken  of.  In  this  method  a  roll  of  gray  cloth  is  so  disposed 
behind  the  machine  that  the  fabric  can  be  conducted  five  times  through  the  machine  before 
finally  going  away  to  be  wound  on  a  beam  for  removal.  There  are,  therefore,  5  layers  of 
cloth  under  the  white  calico  when  printing,  which  give  a  sufficiently  elastic  bed  for  printing 
from  ;  and  very  delicate  shapes  can  be  got.  Any  given  part  of  the  gray  cloth  is  5  times 
uppermost  on  the  pressure  cylinder,  and  consequently  1  piece  of  gray  cloth  is  used  to  print 
5  pieces  of  white.  Gutta  percha  pressure  cylinders,  or  "  bowls,"  have  been  suggested  by 
Dalton,  an  English  printer ;  but,  though  theoretically  preferable  to  iron,  they  do  not  appear 
to  be  much  used. 

The  proper  hygrometric  state  of  calico  when  printing  should  be  attended  to  ;  very  dry 
calico  does  not  take  colors  or  mordant  nearly  so  well  as  when  containing  a  certain  amount 
of  hygrometric  moisture.  Practically  this  is  attained  by  the  bleached  pieces  being  stored  in 
the  "  white  room,"  generally  several  hundred  pieces  in  advance,  and  they  easily  absorb 
sufficient  moisture  from  the  air  to  be  in  a  proper  state  for  printing  on. 

Pieces  after  printing  by  either  block  or  machine  are  rarely  put  through  the  next  opera- 
tions at  once,  but  are  for  the  most  part  hung  in  spacious  airy  chambers  in  folds,  from  an 
arrangement  of  rails  at  the  top  of  the  room.  These  chambers  are  kept  at  an  equable  sum- 
mer temperature,  and  in  proper  hygroscopic  conditions,  due  ventilation  being  also  provided. 
These  "  ageing  I'ooms,"  as  they  are  called,  are  in  several  print  works  of  enormous  dimen- 
sions, and  are  generally  separate  buildings.  Those  of  Messrs.  Edmund  Potter  &  Co.,  and 
Messrs.  Thomas  Hoyle  &  Co.,  in  Lancashire,  may  be  particularized  as  forming  quite  a  feature 
in  the  works.  The  pieces  stay  in  these  chambers  from  1  to  6  days,  according  to  the  style 
of  work,  during  which  time  the  color  which  was  deposited  on  the  outside  of  the  fibre  gradu- 
ally permeates  it,  and  becomes  more  firmly  attached,  a  portion  of  the  base  being  deposited, 
and  acetic  acid  given  off  in  vapors.  Where  colors  are  required  to  absorb  a  certain  amount 
of  oxygen,  such  as  iron  mordant,  catechu  browns,  &c.,  they  find  the  necessary  conditions 
here.  On  the  proper  ageing  of  printed  goods  depends  in  a  great  measure  the  success  of 
many  styles ;  should  the  room  be  too  hot  or  too  dry,  imperfect  fixation  of  the  color  ensues, 
and  meagre  and  uneven  tints  are  obtained  in  the  subsequent  operations.  In  countries 
where  in  summer  the  atmosphere  is  dry,  great  difficulty  is  found  in  ageing  properly.  In 
America  catechu  browns  have  been  known  to  require  weeks  before  being  of  the  proper 
shade.  These  are  of  course  exceptional  cases  ;  the  scientific  printer  knows  how  to  combat 
these  evils  by  the  introduction  of  watery  vapor,  or  even  by  erecting  his  ageing  room  over  a 
reservoir  of  water,  with  rather  open  boarding  for  floor ;  many  colors  also  may  have  deli- 
quescent salts  introduced.     In  England  the  process  of  ageing  is  of  pretty  uniform  duration. 

Quite  recently  several  printers  have  begun  to  adopt  a  method  of  "  ageing,"  which  prom- 
ises to  revolutionize  the  old  way  of  hanging  for  several  days,  and  thus  occupying  a  large 
space.  In  a  patent  of  Mr.  John  Thorn  for  sulphuring  mousseline-de-laines,  a  claim  is  made 
for  using  the  same  apparatus,  or  a  modification  of  it,  for  passing  calico  printed  goods 
through  a  mixture  of  air  and  aqueous  vapor.  Pieces,  after  leaving  the  hot  room  in  which 
they  are  dried  after  printing,  are  run  over  rollers  arranged  in  a  narrow  room,  above  and 
below.  A  very  small  quantity  of  steam  is  allowed  to  escape  into  this  room,  which  is  kept 
slightly  warm  by  the  steam-pipes.  The  pieces,  on  issuing  from  the  apparatus,  should  feel 
soft  but  not  moist ;  they  are  loosely  folded  together,  and  stay  in  this  state  one  night  and 
are  taken  to  the  dyehouse  next  day.  It  is  even  stated  that  this  one  night's  age  may  be  dis- 
pensed with,  and  the  pieces  dunged  off  after  five  or  six  hours'  age. 

The  thickening  of  mordants  and  colors  is  a  subject  of  very  great  importance  to  the 
printer.  It  is  obvious  that  a  mere  solution  of  salts  or  coloring  matters,  such  as  used  in  dyeing, 
cannot  be  used  in  printing  a  pattern  ;  capillary  attraction  speedily  causes  such  a  solution  to 
spread  beyond  the  limits  of  the  pattern,  and  nothing  but  confusion  is  the  result.  A  proper 
degree  of  inspissation  is  then  essential.  To  the  capability  of  very  thick  color  being  printed 
by  engraved  plates  or  rollers  under  severe  pressure  is  due  the  superior  smartness  of  outline 
characteristic  of  goods  produced  by  these  means.  Where  color  can  be  laid  on  the  outside 
of  the  cloth,  so  as  to  penetrate  as  little  as  possible  to  the  other  side,  much  brighter  shades 
are  produced.  In  order  to  obtain  the  most  brilliant  shades  of  color,  it  is  necessary  tliat  the 
cloth  act  as  a  sort  of  mirror  behind  the  color,  which  cannot  be  the  case  if  the  fibre  is  per- 
fectly saturated  with  color.  Independent  of  this,  a  great  economy  of  coloring  material  fol- 
lows from  the  proper  application  of  the  color  or  mordant  to  the  face  only.  This  is  especial- 
ly noticeable  in  madder  goods,  where  the  mordant,  if  printed  in  excess,  is  apt  to  give  up  a 
portion  from  the  cloth  in  the  dyebeck,  thereby  consuming  a  certain  quantity  of  madder  in 
pure  loss. 

The  color-house  should  be  a  spacious  apartment  on  the  ground  floor,  with  the  roof 
ventilated  in  such  a  manner  that  the  steam  produced  finds  a  speedy  exit;  at  one  end,  or 
down  one  side,  is  fixed  a  range  of  color-pans,  varying  in  size,  and  supplied  with  steam  and 
cold  water.  Color-pan.s  are  usually  made  to  swing  on  pivots,  whereby  they  are  easily 
emptied  and  cleaned.     A  range  of  this  sort,  as  manufactured  by  Messrs.  Storey  &  Co.,  of 


2U 


CALICO  FEINTING. 


Manchester,  is  represented  in  Jip.  120.  This  range  consists  of  8  double-cased  copper  pans, 
containing  from  1  to  28  gallons,  riveted  together  at  the  top,  wired  at  the  edges,  and  made 
peifectly  steam-tight ;  they  are  supported  on  cast-iron  pillars,  and  are  so  arranged  or  fitted 
as  to  swivel  or  turn  over  when  the  color  is  required  to  be  emptied,  by  means  of  a  brass 
stuffing  box  attached  to  pan,  and  working  in  the  corresponding  part  attached  to  pillar  on 
the  one  side,  and  moving  at  the  other  on  a  plain  brass  nozzle,  supported  by  a  pedestal  pro- 
jecting from  pillar,  the  nozzle  having  a  blank  end,  thereby  cutting  off"  the  communication 
of  steam,  which  is  carried  to  the  following  pan.  They  are  also  supplied  with  a  condense 
tap  to  carry  off  the  waste  steam  and  water.  Each  pillar  in  the  range,  except  the  last,  is 
supplied  with  a  brass  tap  on  the  top,  with  3  flanges,  to  connect  the  steam  and  cold  water 
pipes,  as  more  fully  explained  hereafter. 


122 


123 


120 


f 


r-^ W- 


f 


fe 


W i? 


^ 


mo 


iJaQ 


^  :^     ~^ 


^^fii.  120,  is  a  copper  pipe,  with  one  blank  end,  and  open  at  the  other  with  flange  for 
the  admission  of  steam,  which  passes  through  the  downward-bent  pipe  marked  b,  in  con- 
nection with  the  brass  tap  on  top  of  pillar,  the  plug  of  this  tap  being  open  at  bottom  to 
admit  the  steam  down  the  pillar  as  far  as  the  stuffing  box,  marked  e,  through  which  it 
rushes  into  the  casing  of  pans,  and  out  by  the  condense  pipe  d,  when  required,  c  is  a  cop- 
per pipe,  with  one  blank  end  and  open  at  the  other,  for  the  admission  of  cold  water  for 
cooling  the  color  after  boiling,  and  is  likewise  connected  with  the  tap  on  top  of  pillar,  as 
shown  m  Jig.  121,  marked  /",  the  water  passing  through  precisely  in  the  same  manner  as  the 
steam  in  a.  n  is  the  condense  pipe,  with  one  blank  end  and  open  at  the  other,  with  flange, 
underneath  the  pans,  to  carry  off  the  water  or  steam,  and  is  supplied  with  ground  brass 
nozzles,  to  fit  the  condense  tap  at  bottom  of  pan,  being  accurately  adjusted,  so  that  in  the 
swivelling  of  pan  it  leaves  its  seat  and  returns  perfectly  steam-tight.  Fig.  121  represents 
an  end  view  of  range,  showing  more  fully  the  po.Htion  and  connection  of  steam  and  cold 
water  pipes  to  bra-ss  tap,  the  cold  water  pipe  miming  along  back  of  range,  the  steam  pipe 
above,  parallel  with  centre  of  pans,  and  the  downward-bent  pipe  in  front ;  and  likewise  the 
stoppage  in  pillar,  so  far  as  is  necessary  there  should  be  an  aperture  for  the  steam  or  water 
to  meet  the  brass  stuffing  box.  In  th'i^  fig.  is  also  shown  the  copper  pipe,  with  elbow  swivel 
tap,  for  supplying  pans  with  cold  water,  (one  pipe  to  supply  two  pans,)  and  fixed  on  top  of 
cold  water  pipe  exactly  o])posite  pillar,  as  further  sho^\^l  in  Jig.  122  marked  g.  Fig.  123 
is  an  end  view  of  range,  with  pillar  cut,  in  order  to  show  the  position  of  condense  tap  at 
bottom  of  pan,  and  its  connection  with  condense  pipe,  and  where  the  point  of  separation 
takes  place  in  swivelling,  by  the  line  marked  h.     It  will  be  seen  by  the  foregoing  that  the 


CALICO  PRINTING. 


245 


process  of  boiling  and  cooling  is  rapid  and  certain,  every  thing  being  accurately  adjusted 
and  steam-tight  throughout  the  whole  apparatus. 

The  colors  are  placed  in  these  pans  and  stirred  well  all  the  time  they  are  being  boiled ; 
good  stirring  is  very  essential  to  produce  smooth  colors.  This  was  formerly  done  by  hand 
with  a  flat  stick,  but  lately  the  best  print  works  have  been  fitted  with  machinery  over  the 
pans  to  stir  mechanically.  A  very  effective  plan  of  this  sort  is  represented  in  Jigs. 
124  and  125.  It  is  that  of  Messrs.  Mather  and  Piatt,  of  Manchester,  the  boilers  in  this 
drawing  being  not  reversible,  though  the  plan  can  be  just  as  easily  adapted  to  that  descrip- 

124 


tion  of  pans.     Fifi.  121  is  a  front  elevation;  fig.  125  is  a  transverse  section,  awAjig.  12G  is 
a  sectional  plan,  the  same  letters  referring  to  all.     a  is  a  horizontal  shaft  above  the  pans, 

ft  fitted  with  a  pair  of  mitre  wheels,  b  b,  for  each  pan.  The  vertical  wheel  b  is  not  keyed  on 
the  shaft  a,  but  is  brought  into  connection  with  it  when  required  by  the  catch  box  c,  which 
slides  on  a  key  on  the  shaft,  and  revolves  with  it  (see  stnall  cuts) ;  the  catch  box  is  worked 
by  a  lever  handle  d,  and  thus  motion  is  given  to  the  vertical  shaft  e.  The  shafts  a  and  c 
are  both  supported  by  the  framewoi-k  /,  fastened  to  the  wall ;  the  shaft  e  is  terminated  by 
the  frame  g  h  r/,  the  centre  of  which,  A,  is  a  continuation  of  the  shaft  e  \  and  the  wings  g 
are  hollow  to  carry  the  shafts  ^•,  which  are  surmounted  by  the  cog  wheels  i  i,  which  gear 
into  a  cog  wheel  /  on  the  shaft  e.  The  agitators  n  >i  are  made  of  flat  brass  rod,  and  are 
curved  to  fit  the  bottom ;  they  are  connected  with  the  shafts  k  k  by  a  hook  joint,  which  is 
steadied  by  the  conical  sliding  ring  m ;  the  agitators  thus  hang  from  the  shaft  e,  and  nearly 
touch  the  bottom  of  the  boiler.  When  the  shaft  e  is  put  in  motion,  the  agitators  have  two 
movements,  one  round  each  other,  and  also  each  on  its  own  axis ;  as  they  are  set  at  right 
angles  to  each  other,  as  shown  in  fig.  126,  it  follows  that  no  part  of  the  pan  can  escape 
being  stirred.  When  the  color  is  made,  the  piece  m  is  slid  up  on  A-,  and  the  agitators  un- 
hooked and  taken  out,  the  waste  of  color  b.cing  very  trifling,  in  consequence  of  the  agita- 
tors being  outlines  only.     The  saving  of  labor  effected  in  a  color  house  by  this  machinery 

-  is  very  great,  as,  after  turning  on  the  steam,  the  pan  may  be  left  to  itself  till  the  color  is 
finished. 

From  the  great  variety  of  substances  used  in  mordants  and  colors,  of  very  different 
chemical  properties,  a  variety  of  thickening  substances  is  required.  Chemical  combination 
between  the  mordants  or  color  and  the  thickening  substance  is  to  be  avoided  as  much  as 
possible,  for  such  combination  may  be  regarded  as  so  much  pure  loss,  the  fibre  of  the 
fabric  not  being  able  to   decompose  and  assimilate  them.     Several  circumstances  may 


246 


CALICO  PRINTING. 


125 


require  the  consistence  of  the  thickening 
to  be  varied  ;  such  as  the  nature  of  the 
mordant,  its  density,  and  its  acidity.  A 
strong  acid  mordant  cannot  be  easily 
thickened  with  starch ;  but  it  may  be  by 
roasted  starch,  vulgarly  called  British 
gum,  and  by  gum  arable  or  Senegal. 
Some  mordants  which  seem  sufficiently 
inspissated  with  starch,  liquefy  in  the 
course  of  a  few  days ;  and  being  apt  to 
run  in  the  printing-on  make  blotted  work. 
In  France,  this  evil  is  readily  obviated, 
by  adding  one  ounce  of  spirits  of  wine  to 
half  a  gallon  of  color. 

The  very  same  mordant,  when  inspis- 
sated to  different  degrees,  produces  dif- 
ferent tints  in  the  dye-copper ;  thus,  the 
same  mordant,  thickened  with  starch,  fur- 
nishes a  darker  shade  than  when  thick- 
ened with  gum.  Yet  there  are  circum- 
stances in  which  the  latter  is  preferred, 
because  it  communicates  more  transpa- 
rency to  the  dyes,  and  because,  in  spite 
of  the  washing,  more  or  less  of  the  starch 


always  sticks  to  the  mordant.  Gum  has  the  inconvenience,  however,  of  drying  too  speedily, 
and  forming  a  hard  crusrt  on  the  cloth,  which  does  not  easily  allow  the  necessary  capillary 
attraction  to  take  place,  and  the  tints  obtained  are  thin  and  meagre.  The  substances  gen- 
erally employed  in  thickening  are : — 


1.  Wheat  flour. 

2.  "       starch. 

3.  Torrefied  wheat  starch,  or  British 

gum. 

4.  Torrefied  potato  farina. 

5.  (lum  substitutes  or  soluble  gums. 

6.  Gum  Senegal. 

7.  Gum  tragacantb. 

8.  Salcp. 


9.  Pipe-clay  or  china-clay  mixed  with 
gum  Senegal. 

10.  Sulphate  of  lead. 

11.  Molasses. 

12.  Dextrine. 

13.  Albumen  of  eggs. 

14.  Lactarine. 
1.5.  Gluten. 
IG.  Glue. 


CALICO  PEINTING. 


247 


Those  most  used  are  the  first  seven.  The  rest  are  only  adapted  for  special  styles  or 
colors.  The  artificial  gums  produced  by  roasting  starch  or  farina  are  very  largely  in  use. 
The  action  of  heat  on  starch  causes  a  modification  in  it.  According  to  the  degree  of  heat 
and  its  duration  a  greater  or  less  modification  ensues,  the  higher  tlie  heat,  the  more  soluble 
in  water  the  gum,  but  also  the  browner  and  of  least  thickening  properties.  The  addition 
of  various  acids  and  alkalies  to  starch  or  farina  before  calcination,  causes  them  to  become 
soluble  at  lower  temperatures  than  without ;  different  acids  also  produce  dift'erent  results ; 
those  most  generally  used  are  nitric,  acetic,  muriatic,  oxalic,  and  recently  lactic  acid  has 
been  proposed  by  Pochin.  The  proportion  of  acid  used  is  very  small,  and,  though  the 
effect  is  produced,  the  acid  disappears  during  calcination.  Small  quantities  of  alkahes  are 
also  used  for  special  modifications  of  these  gum  substitutes.  The  making  of  these  gums  is 
a  distinct  branch  of  trade,  and  finds  employment  for  large  capital  and  numerous  hands.  In 
giving  the  receipts  for  the  various  colors,  care  will  be  taken  to  specify  the  nature  and  pro- 
portion of  thicliening  to  be  employed  for  each  color;  a  most  important  matter,  often 
neglected  by  English  writers  upon  calico  printing. 

It  is  often  observed  that  goods  printed  upon  the  same  day,  and  with  the  same  mordant, 
exhibit  inequalities  in  their  tints.  Sometimes  the  color  is  strong  and  decided  in  one  part 
of  the  piece,  while  it  is  dull  and  meagre  in  another.  The  latter  has  been  printed  in 
too  dry  an  atmosphere.  In  such  circumstances  a  neutral  mordant  answers  best,  espe- 
cially if  the  goods  be  dried  in  a  hot  flue,  through  which  humid  vapors  are  in  constant  cir- 
culation. 

In  padding,  where  the  whole  surface  of  the  calico  is  imbued  with  mordant,  the  drying 
apartment  or  flue,  in  which  a  great  many  pieces  are  exposed  at  once,  should  be  so  con- 
structed as  to  afford  a  ready  outlet  to  the  aqueous  and  acid  exhalations.  The  cloth  ought 
to  be  introduced  into  it  in  a  distended  state ;  because  the  acetic  acid  may  accumulate  in  the 
foldings,  and  dissolve  out  the  earthy  or  metallic  base  of  the  mordant,  causing  white  and 
gray  spots  in  such  parts  of  the  printed  goods.  Fans  may  be  employed  with  great  advan- 
tage, combined  with  Hot  Flues.     See  Ventilation. 

The  mordant  and  thickening,  or  the  dye  decoction  and  thickening,  being  put  in  one  of 
the  copper  pans,  is  stirred  by  hand  or  machinery  and  boiled  till  perfectly  smooth ;  the  steam 
then  being  shut  off,  cold  water  is  admitted  to  the  double  casing,  and  the  color  cooled.  It 
is  then'emptied  out  of  the  pan  into  a  straining  cloth,  stretched  over  a  tub,  and  strained  to 
remove  all  gritty  particles,  which  would  be  very  injurious  to  the  copper  rollers.  A  very 
useful  straining  machine  has  been  recently  invented  by  Dollfus  Mieg  &  Co.,  and  patented  in 
this  country.  This  maciiine  is  shown  in  Jiff.  127.  It  consists  of  a  case  or  cylinder,  in  which 
a  piston  is  worked,  either  by  hand  or  power,  to  press  the  color  through  a  cloth  made  of 
cotton,  linen,  hair,  or  other  suitable  material  at  the  bottom  of  the  case  or  cylinder ;  or,  in- 
stead of  the  said  cloth,  a  wire  gauze  may  be  used.  The  bottom  of  the  piston  may  be  made 
of  wood,  copper,  brass,  gutta  percha,  caoutchouc,  or  other  suitable  material.  The  manner 
of  working  the  apparatus  will  be  clearly  understood  by  reference  to  the  drawings,  in  which 
fiff.  127  is  a  side  elevation  of  the  said  machine  or  apparatus,  andjir/.  128  a  front  elevation 
of  the  same,  a  represents  the  case  or  cylinder,  which  is  strengthened  at  its  upper  part  by 
the  iron  band  b,  and  also  at  its  lo\ter  part  by  the  ring  a.  The  skeleton  plate  b,  which  forms 
the  bottom  of  the  cylinder,  is  removable,  and  sustained  by  the  four  hooks  c.  To  disengage 
the  plate  b,  springs  are  fitted  on  the  ring  d,  which  act  upon  two  of  the  hooks  o,  so  as  to 
throw  them  out  from  under  the  grid  b.  Upon  the  ring  a  the  second  ring  d  is  laid,  which 
supports  the  circular  handle  e.  The  upper  parts  of  the  four  hooks  c  lay  upon  four  inclined 
planes  fitted  on  the  ring  d.  The  modus  operandi  is  as  follows : — If  the  ring  d  is  turned 
right  or  left,  the  skeleton  plate  6,  on  which  one  of  the  said  cloths  or  wire  gauze  has  pre- 
viously been  placed,  will  be  brought  firmly  up  to  the  extremity  of  the  cylinder  a  ;  and  if 
the  said  cylinder  be  filled  with  coloring  matter,  the  piston  m,  being  worked  by  the  pulley  e, 
the  wheels  f,  g,  n,  i,  k,  and  the  rack  l,  will  force  it  through  the  cloth  or  sieve,  to  be  re- 
ceived in  a  vessel  under  it  for  the  purpose  ;  and  by  a  proper  arrangement  of  the  teeth  of 
the  said  rack  l,  the  piston  can  only  descend  to  any  required  point  in  the  cylinder.  To 
facilitate  the  working  of  the  apparatus  and  increase  its  general  efficiency,  the  cylinder  is 
fixed  on  pivots  at  n,  so  that  it  may  be  easily  inclined  or  brought  towards  the  operator  for 
the  purpose  of  introducing  the  coloring  matter  or  cleaning  the  vessel.  To  the  ring  or  band 
B  are  fixed  the  two  handles/ and  the  two  catches  h.  The  catches  being  raised  from  the 
notch  k  on  the  frame  p,  the  cylinder  may  be  pulled  forward  by  means  of  the  handles/,  till 
the  hooks,  being  acted  upon  by  a  spring,  re-engage  themselves  at  k  on  the  lowtr  part  of  the 
frame  p,  and  vice  vcnsd.  On  the  shaft  x  is  placed  a  second  wheel  q,  by  whidi  a  reverse 
motion  is  obtained,  and  the  piston  m  raised  to  its  original  position. 

Colors  for  printing  by  block  are  for  the  mo.st  part  thickened  in  the  same  manner  as 
those  for  machine,  l)ut  are  made  thinner,  since  very  thick  color  cannot  be  applied  by 
block.  Some  substances  also  can  be  used  in  block  printing  that  arc  inapplicable  to 
machine,  such  as  pipe-clay  and  china-clay,  which,  however  finely  ground,  still  contain 


248 


CALICO  PRINTING. 


127 


128 


gritty  particles,  which  would  speedily  scratch  and  destroy  the  delicate  engraving  of  the 
machine  rollers. 

A  spacious  drug  room  is  attached  to  the  color-house  where  all  the  drugs  used  are  kept 
away  from  the  steam  of  the  color-house.  Near  the  color-house  should  be  a  well-appointed 
laboratory,  where  drugs  can  be  tested  and  experiments  made. 

Formerly,  all  the  decoctions  and  mordants  used  in  piint-works  were  made  on  the  spot, 
but  the  trade  having  very  much  extended,  the  manufacture  of  the  various  mordants  and 
decoctions  of  dyewood  is  now  a  separate  business,  and  printers  can  be  supplied  with  these 
articles  at  the  same  or  in  some  cases  a  lower  rate  than  they  could  be  produced  for  on  the 
woiks,  the  ((uality  also  being  uniform  and  good.  The  printer  now  only  makes  for  himself 
a  i\;vf  unimportant  articles.  The  province  of  the  foreman  color  maker,  who  is  generally  a 
well-paid  and  responsible  servant,  is  to  combine  these  primary  materials  so  as  to  form  the 
different  colors  reciuired  for  the  different  styles  of  work ;  as  the  taste  of  customers  varies, 
he  is  required  to  be  able  to  make  any  given  variation  of  shade  at  will,  and  be  able  to  judge 
of  the  quality  of  the  various  materials  submitted  to  him.  The  ordinary  decoctions  that  are 
kept  in  stock  in  the  color  dei)artment  are : — 


Logwood  liquor. 
Peachwood  liquor. 
Sapan  liquor. 
Quercitron  bark  liquor. 


Gall  liquor. 
Persian  berry  liquor. 
Cocliineal  liquor. 
J'ustic  liquor 


Catechu  liquor. 
Ammoniacal    cochineal 

liquor. 
Extract  of  indijro. 


CALICO  PRINTING. 


249 


And  the  various  mordants  and  solutions  are  : — 


Red  liquor,  or  acetate  of 

alumina. 
Iron  liquor,  or  acetate  of 

iron. 
Buff  liquor,  or  pyrolig- 

nite  of  iron. 
Pcrnitrate  of  iron. 
Permuriate  of  iron. 
Protomuriate  of  iron. 


Ammonia  liquor. 
Acetic  acid. 
Pyioligneous  acid. 
Nitric  acid. 
Muriatic  acid. 
Sulphuric  acid. 
Caustic  soda  liquor. 
Caustic  potash  liquor. 


Protochloride  of  tin  in  so- 
lution. 

Oxymuriate  of  tin  in  solu- 
tion. 

Nitrate  of  copper  in  solu- 
tion. 

Acetate  of  copper  in  solu- 
tion. 

Lime  juice. 

Many  other  dry  acids  and  salts  are  also  kept  in  stock.  For  the  constitution  of  the  vari- 
ous mordants  and  their  preparation  see  Mordants.      ' 

It  would  be  impossible  to  particularize  all  the  styles  of  calico  printing.  The  variety  is 
infinite  ;  but  they  may  be  broadly  classed  as  follows: — 

I.     Madder  styles,  varieties  of  which  are — 

a.  The  simplest  form  is  a  pattern  printed  in  mordants  on  white  ground,  such  as  black 
and  red  ;  black,  red,  and  purple  ;  black  and  two  reds,  &c.,  chocolate  being  sometimes  sub- 
stituted for  black,  and  brown  from  catechu  being  also  introduced ;  these  are  dyed  with  mad- 
der, the  ground  remaining  white. 

b.  Any  or  all  of  the  above  mordants,  together  with  lime  juice,  technically  termed  acicl, 
printed,  and  a  fine  pattern  printed  all  over  or  covered  in  purple  or  light  chocolate,  then  dyed 
madder.  In  this  style  the  red  is  a  peculiar  one,  termed  resist  red ;  and  the  result  when 
dyed  is,  that  the  acid  and  red  have  prevented  the  purple  or  chocolate  fixing  on  those  parts, 
the  red  remaining  pure  and  the  acid  having  formed  a  white,  the  rest  of  the  ground  being 
covered  with  the  fine  pattern  or  cover ;  of  this  style  large  quantities  are  printed  in  black, 
purple,  and  acid,  and  covered  in  paler  purple,  the  cover  roller  being  any  small  full  pattern, 
and  this  not  being  required  to  fit  to  the  other  pattern,  a  great  variety  of  effects  may  be  pro- 
duced by  varying  the  cover :  often  a  still  weaker  purple  is  padded  or  blotched  in  a  plain 
shade  all  over  the  piece,  and  in  this  case  the  only  white  in  the  pattern  is  that  reserved  by 
the  acid. 

c.  The  French  pink  style,  which  is  wholly  various  shades  of  reds  or  pinks,  and  is  printed 
in  one  or  more  shades  of  red  and  acid,  then  covered  or  blotched  in  pale  red,  then  dyed 
madder  and  subjected  to  a  peculiar  clearing  with  soap,  whereby  pink  shades  of  very  great 
delicacy  are  obtained. 

All  these  are  what  are  termed  fa'^t  colors,  and  having,  after  dyeing,  undergone  severe 
soaping,  cannot  be  altered  by  the  usual  domestic  washing  process. 

II.  The  same  styles  are  dyed  with  garanein  instead  of  madder ;  heavier  and  darker  col- 
ors being  employed.  These  goods  are  not  soaped,  garanein  producing  bright  colors  at  once, 
but  the  shades,  though  stil  classed  as  fast  colors,  do  not  possess  the  permanence  of  those 
dyed  with  madder. 

III.  The  first  style  is  frequently  relieved  by  lively  colors,  such  as  green,  blue,  yellow, 
&c.,  blocked  in  after  dyeing  and  clearing  ;  these  colors  are  generally  what  are  termed  steam- 
colors,  being  fixed  by  steaming  the  cloth,  and  afterwards  washing  in  water  only,  or  the 
printed  or  dyed  pattern  is  covered  with  a  resist  paste  blocked  on,  and  various  shades  of 
drab,  slate,  buff,  &c.,  printed  with  a  small  pattern  all  over;  sometimes  these  colors  are 
mordants,  to  be  subsequently  dyed  with  cochineal,  quercitron  bark,  &c.,  or  they  may  be 
colors  composed  of  dyewood  decoctions,  mixed  with  mordants,  and  are  fixed  by  passing 
through  soda  or  other  solutions.  The  result  in  either  case  being  that  the  original  pattern, 
generally  a  group  of  flowers,  being  protected  by  the  paste  which  prevented  the  subsequent 
color  fixing  there,  stand  out  pure,  the  rest  of  the  ground  Ijeing  covered  by  the  small  pat- 
tern or  cover.  White  may  be  also  reserved  by  the  paste,  and  frequently  these  white  parts 
are  blocked  with  blue,  yellow,  green,  &c.,  as  before. 

IV.  Padded  styles. — In  these  the  cloth  is  first  padded  (as  will  be  hereafter  explained)  all 
over  with  a  liquid  mordant,  dried  and  printed  in  spots  or  figures  vcith  strong  acid,  or  dis- 
chnrge  as  it  is  called,  then  put  through  the  dyeing  operations  necessary  for  the  shade  re- 
quired ;  the  printed  spots  remaining  white,  and  the  rest  of  the  piece  one  plain  shade.  The 
white  portions  are  freiiuently  relieved  by  steam-colors  blocked  in. 

v.  Indigo-blue ;  a  style  of  considerable  importance.  In  this,  a  resist  paste,  cither  alone 
or  accompanied  by  resist  yellow,  or  orange  mordant,  is  printed  on  white  calico,  which  is 
then  dipped  in  the  indigo  vat,  till  the  shade  of  blue  wanted  is  obtained.  If  yellow  or 
orange  is  present,  these  colors  are  raised  with  bichromate  of  potash  liquor.  The  peculiar 
colors  printed  in  this  style  have  the  property  of  preventing  the  indigo  fixing  on  the  printed 
parts,  and  the  result  is  dark  blue  ground,  with  white,  orange,  or  yellow  spots,  steam-colors 
being  sometimes  blocked  in  the  whites. 

VI.  China-blues,  a  modification  of  the  indigo-blue  style,  but  in  this  case  the  pattern  is 
produced  by  indigo-colors,  printed  on  white  cloth  :  the  pieces  are  next  put  through  a  pecu- 


250  CALICO  FEINTING. 

liar  process  fixing  the  indigo  in  the  cloth,  the  result  being  blue  figures  on  white  ground. 
All  indigo  styles  are  fast  or  permanent. 

VII.  Turkey-red  and  discharge. — On  dyed  Turkey-red  cloth  is  printed  an  acid,  or  acid 
solutions  mixed  with  pigments  or  salt  of  lead  ;  the  printed  pieces  are  passed  through  chlo- 
ride of  lime  solution,  when  chlorine  is  eliminated  by  the  acid  colors,  and  discharges  the  red. 
The  pigments  or  lead-salt  being  fixed  in  the  cloth  at  the  same  time,  after  washing  and 
chroming  where  yellow  has  to  be  obtained,  the  piece  presents  a  pattern,  bitten  as  it  were  in 
the  Turkey-red  ground.  Black  is  also  printed  along  with  the  other  colors.  A  modification 
of  this  style  is  the  well-known  Bandanna  style  used  for  handkerchiefs.  Turkey-red  cloth 
is  folded  in  a  hydraulic  press  on  a  lead  plate  perforated  with  a  pattern.  When  a  sufficient 
number  of  folds  are  made  on  this  plate,  a  precisely  similar  plate  is  put  on  the  top,  so  as  to 
register  accurately  with  the  bottom  one  ;  pressure  being  now  applied,  the  cloth  is  squeezed 
tightly  between  the  two  plates,  a  top  being  opened  above  the  upper  plate,  solution  of  chlo- 
rine is  forced  through  the  perforations,  and  in  its  passage  through  the  cloth,  discharges  the 
dye  ;  the  chlorine  liquor  is  followed  by  water,  and  the  operation  is  finished  :  the  pieces 
when  removed  from  the  press  being  discharged,  according  to  the  pattern  of  the  lead  plates. 

VIII.  Steam-colors. — In  this  style  colors  are  formed  from  mixtures  of  dyewood  extracts 
and  mordants,  together  with  various  acids  and  salts,  and  being  printed  on  calico  which  has 
been  mordanted  with  peroxide  of  tin,  the  pieces  are  exposed  to  steam  at  212°  in  close  ves- 
sels, which  causes  an  intimate  union  of  the  calico  with  the  dyewood  extract  and  mordant,  so 
that  subsequent  washing  with  water  removes  only  the  thickening  substance,  and  leaves  the 
cloth  dyed  according  to  the  pattern  in  various  colors.  Woollen  fabrics  and  de-laines  are 
always  printed  in  this  manner,  and  also  often  silk  ;  animal  fabrics  not  being  well  adapted 
for  mordanting  and  dyeing  in  the  same  manner  as  cotton  fabrics,  owing  to  the  peculiar 
property  of  wool  to  absorb  coloring  matters,  which  renders  the  obtaining  of  whites  an  im- 
possibility where  the  wool  is  steeped  in  a  dye  decoction.  These  steam-colors  are  very 
brilliant  and  tolerably  permanent  to  light,  but  do  not  withstand  hot-soap  solution  which 
alters  their  shades. 

IX.  Spirit  colors  arc  made  in  somewhat  the  same  manner  as  the  steam-colors,  but  con- 
tain larger  quantities  of  mordant  and  acid,  and  will  not  bear  steaming,  because  the  calico 
would  be  too  much  tendered  by  the  acid,  and  are  therefore  only  dried  and  hung  up  a  day 
or  two,  and  then  washed  in  water.  They  are  the  most  brilliant  colors,  but  generally  fugitive 
and  are  not  much  used. 

X.  Bronzes.,  formerly  a  style  in  large  demand,  but  now  almost  obsolete  ;  done  by  pad- 
ding the  cloth  in  solution  of  protochloride  of  manganese,  precipitating  the  oxide  by  means 
of  alkali,  peroxidizing  this  by  chloride  of  lime,  and  then  printing  on  colors  composed  of 
protochloride  of  tin  and  pigments  or  decoctions  ;  the  protochloride  of  tin  immediately  de- 
oxidizes, bleaching  the  brown  oxide  of  manganese,  and,  where  mixed  with  decoctions  or  pig- 
ment, leaving  a  dyed  pattern  cutting  through  tlie  ground. 

XI.  Pigment-printing. — The  colors  in  this  class  are  the  same  pigments  as  used  by 
painters,  such  as  Scheele's  green,  ultramarine  blue,  chrome  yellow,  &c.,  and,  being  quite 
insoluble  in  water,  are,  so  to  speak,  cemented  to  the  fibre.  The  vehicle  used  for  fixing 
these  is  generally  albumen,  which  coagulates  when  the  cloth  is  steamed,  and  imprisons  both 
cloth  and  fibre  with  the  coagulum  ;  of  course  these  colors,  though  not  altered  in  shade  by 
soap,  are  detached  in  part  by  severe  treatment,  such  as  rubbing,  &c. 

First  Style :  Madders. 

Madder  styles  being  the  most  important,  demand  the  most  detailed  descriptions.  The 
colors  used  are  of  the  class  termed  mordants,  which,  not  coloring  matters  themselves,  act  by 
combining  with  both  cloth  and  coloring  matter.  They  are  generally  the  acetates  or  pyrolig- 
nites  of  iron  and  alumina. 

lied  Liquor  is  the  technical  name  of  the  pyrolignite  of  alumina  used  as  mordant  for 
red,  &c. 

Iron  Liqnor  is  the  pyrolignite  of  iron  used  as  mordant  for  black,  purple,  &c. 

The  preparation  of  these  liquors  on  a  large  scale  forms  a  separate  business,  and  will  be 
found  described  under  the  head  Mordants. 

Fixing  Liquor. — For  a  long  time  it  has  been  customary  to  add  to  black  and  purple 
colors,  or  mordants,  some  substance  which  has  a  tendency  to  prevent  the  oxide  of  iron  from 
passing  to  the  state  of  peroxide.  The  oxide  of  iron  necessary  to  produce  the  best  results 
with  madder  is  a  mixture  of  protoxide  and  peroxide  of  iron,  probably  the  black  or  magnetic 
oxide,  though  this  point  is  not  precisely  determined.  If  the  oxide  should  pass"  to  the  red 
oxide  state,  inferior  shades  are  produced  ;  and  the  object  of  the  printer  introducing  fixing 
liquor  into  his  color  is  to  prevent  tliis  injurious  tendency. 

The  earliest  fixing  liquor  used  was  a  solution  of  arsenious  acid  ;  and  though  other  fixers 
have  from  time  to  time  l)een  introduced,  the  preparations  of  arsenic  still  hold  their  ground. 
A  very  good  fixing  litiuor,  that  has  been  much  used  in  France  and  England,  is  made  as 
follows : — 


CALICO  FEINTING.  251 

•    ■^n  ,u"  ^''"'P^fi^^^U  Liquor.— n  gallons  water,  U  gallons  acetic  acid   9  lbs  sal  ammo 
""'"in  isi^rrh  '  m'  '  '"^  'f  the  arsenic.is  dissolved,  and  let  stand'till  quite  clear 

No.  2.  To  100  lbs.  potato  starch,  add  374  gallons  water,  123  <^allons  nitric  acid  snonifin 
gravity  1-3  and  4_oz.  oxide  of  manganese.  Th%  chemical  action  wfuchake  place  'an^'nS 
these  mgredients  is  a  lowed  to  proceed  till  the  nitric  acid  is  destroyed.  To  the  reSm 
thus  produced  are  added  50  gallons  of  pyroligneous  acid,  and  the  compound  is  he  as  ^"an 
mordant  hquor  m  a  fit  state  to  add  to  the  various  mordants  used  in  printing  and  dven" 
Tlie  intention  in  making  this  liquor  is  to  carry  on  the  decomposition  of  the  nitric  acid  and 
starch  as  ar  as  possible  without  forming  oxalic  acid,  and  as  little  as  possible  of  carbonic 
acid  which  IS  gently  aided  by  the  catalytic  action  of  the  oxide  of  manganese,  preventin" 
the  formation  ot  oxahc  acid.  Apparently  there  is  formed  by  this  process  saccharic  acid  o°r 
an  acid  in  a  ow  state  of  oxMation,  which  is  the  active  agent  in  preventing  the  peroiidize- 
men  of  the  iron  when  added  to  purple  mordants.  This'liquor  has  been  fargel/used  and 
^  still  preferred  by  some  printers.     Of  late,  various  fixing  liquors  have  been  made  and  soM 

W?hr«'1"""Af '"''''''  ^y^f^r^'^'t'''''^  "^'^  ^'•^^"''^"^  ^^i^'  ^'  ^^s^^ite  of  soda  form, 
ing  the  staple  of  them  ;  some  of  these  have  chlorate  of  potash  added,  the  object  be  in-  the 
formation  of  arseniate  of  ron  when  the  cloth  is  dried:  whereby  the  acetic''  acdi  more 
speedily  driven  off ;  and  since  arseniate  of  iron  does  not  pass  beyond  a  certain  degree  of 
ox.dizement  in  the  air  the  mordant  is  kept  in  a  proper  state  for  dyeing  good  colors  The 
following  is  also  a  good  purple  fixing  liquor  :—  /      s  fe  ""  i-owrs.     ine 

^.'\'  \P'ZP^^fi^i^9  Liquor.— BoW  together  till  dissolved  2  gallons  water  25  lbs  soda 
heSed  to  Jo 'r  ^'\T.r  Tf  T'^"  ''"°'^^;*;'  f^  ''  ''  S^''«-  -ood  add  previoul; 
quarts  muilL  acid!'*  ''''^'  '"  '  '''  "^  *"^°  ''''  ^''^  '''  ''  *^^  -^'^  ^«  -"^^d.  -^  add  I 

The  following  madder  colors  are  from  some  in  practical  use,  and  though  almost  everv 
color-maker  has  different  receipts  for  his  colors,  they  may  be  taken  to  represent  the  general 
prmciples  on  which  these  colors  are  composed.  f  t  ii^e  geuerai 

In  all  these  colors  the  thickening  substance  is  first  beaten  up  with  a  little  of  the  liquid 
till  quite  fine  and  free  from  lumps,  then  the  remainder  of  the  liquid  added  and  the  w  ole 
strained.  "'      ^^  ""'^  «^  *^^^  double-cased  steam-pans  till  quite  smoolh  rcooledr  and 

No.  4.  Black  for  Machine,  {Madder.)— 4.  gallons  iron  liquor  at  24°  T.  4  eaUons  nvroli"-- 
neous  acid,  4  gallons  water,  24  lbs.  flour;  bofl,  and  add  1  pint  oil         ^•'  ^S'^^o^spyiolig- 

T     ^tJ,M^l"'''^7  f '^'■«T'''  (^{^^^"'"^O-n  gallons  water,  3  gallons  iron  liquor uit  24° 
'  It*  °^  ^   P,"''P'*'  ^'''""  '"*"'"*'  (^^•'-  3')  24  lbs.  flour,  1  pint  oil 
No"  S"    pZtl^i^7  ^\ft''  (/!^«^^,^.'*'^-)-12  gallons  red  liquor  at  18°  T.,  24  lbs.  flour, 
q   with        ^«^t    t-(t  ^f 'f''"  (^^«^/"»'')  are  made  by  reducing  the  standard  liquor  No 

No  8.  Standard  red  Liquor— 10  gallons  hot  water,  40  lbs.  alum,  25  lbs.  white  acetate 
of  lead ;  rake  up  till  dissolved,  let  settle,  and  decant  the  clear 

the  S  of  thickener""*''''"''  ^'^'"'-1*^  S^"«°«  ^^t^^-'  ^0  lbs.  gum  substitute,  No.  5  in 

kA'  n     n    I      '    r''  I'']'}  '',^.'"  ""'^''^y  ^^l'^  ^'JJ  12  lbs.  of  mudate  of  tin  crvstals. 
Ao.  11.  JJark  resi.sf.red  Machine.-S^mc  as  No.  10,  but  6  lbs.  of  tin  crystals'onlv 

when  it  ha7to7J'f'  ^'^  'f  ''  ""''"^  ''^''''  ''  ^'^^  *«  ''''''  ^  chocolate  coAr,  and  No.  11 
wnen  it  nas  to  resist  a  purple  cover. 

watfr^'aiLwS^onTn'^t'^V^''-^^     (^/«/«-ne.)-Made  by  reducing  resist-red  liquor  with 

T    ?  IhTflo         h.M°      1    ^  ,'■  "f""*"''  .^"-  ^'  P^^''^-''^'^=    12  gallons  resist-red  liqtior  at  5° 
1.,  y  lbs.  flour;  boil,  and  add,  when  cool,  2  lbs.  tin  crystals 

is  -1  mnhM^nr/,"''"'  '"■''  ™'^^^/™.'^  "•«»  I'quor  and  red  liquor  mixed,  and  the  red  liquor 

on  ruo?at  24°  t'q'" ',]'''    ^^'^ /."^'ance,   3  chocolate  (madder)  (machine)  :-3  gallons 

Ze     VLu      ■       V    gallons  red  liquor  at  18°  T.,  24  lbs.  flour,  1  pint  oil.     No.  GChoco- 

X^  if  ^/   "■"''  Tf'  ^  ^*    ^•'  ^  S^"«""  ""^  ''^l"""-  at  1«°  T.,  14  lbs.  flour,  4  pint  oil. 

water°'24  ibffloS       -^''''  ^'''''''''''''^  (^/«cAe«c.)_  10  gallons  red  liquor  at  18°  T.,''2  gallons 

flnnf.Vii  ^'''■f-'"=^fo\(^arancin,  (J/«eA»*«.)_l  2  gallons  resist-red  liquor  at  14°  T.,  24  lbs. 
flour;  boil,  cool   and  add  9  lbs.  tin  crystals.     This  for  resisting  chocolate. 

fl./VV      ;■'''fA^^'''"^''*'''(^'^'^'•'''''''^•)—12Kallons  resist-red  liquor  at  14°  T    24  lbs 
flour ;  boil,  cool,  and  add  4^  lbs.  tin  crystal.s.     This  for  resisting  purpli.  ' 

H  n       i  1.1      T'  '^^«";^««^/'»-  Madder. -r^O  gallons  water,  200  lbs  catechu  •  boil  6  hours 
then  add  \\  gallons  acetic  acid,  and  add  water  to  make  ui,  to  50  gallons-  take  ou     and  let 
stand  36  hours,  and  decant  the  clear;  heat  it  to  130^  R,  md  a.l<r90  lbs 'sal  amml'niio  ,1 
wVTpei'glSom   ""^^  ''  '^""^^  '^''^"*  ^^^  ^•^^^'  ^"^  thiik^^^lTirrgum 


252  CALICO  PRINTING. 

No.  IS.  Broim  Color  for  Madder^  {3facJimc.) — 4  gallons  No.  17,  1  gallon  acetate  of 
copper,  (No.  10,)  2  quarts  acetic  acid,  2  quarts  gum  Senegal,  water  4  lbs.  per  gallon. 

No.  10.  Acetate  of  Copper. — 1  gallon  hot  water,  4  lbs.  sulphate  of  copper,  4  lbs.  white 
acetate  of  lead;  dissolve,  let  .«ettlc,  decant  the  clear,  and  set  at  1(5°  T. 

No.  20.  Brown  for  Madder,  {Machine.) — 7  gallons  of  No.  17,  1^  gallons  of  No.  19,  1^ 
gallons  gum-red,  (No.  21.) 

No.  21.   Gum  red. — 3  gallons  red  liquor  at  18°  T.,  12  lbs.  gum  substitute;  boil. 

No.  22.  Brown  for  GaranciUy  {Machine.) — 2  gallons  No.  18,  1  gallon  4  lbs. -gum-substi- 
tute water. 

No.  23.  Brou'ufor  Garancin,{3fachine.) — 2  gallons  No.  17,  3+  gallons  4  lbs. -gum-sub- 
stitute water,  3  quarts  acetic  acid,  3  quarts  No.  19. 

No.  24.  Drab  for  Madder,  {Machine.) — 4  gallons  No.  17,  1  gallon  protomuriate  of  iron 
at  9°  T.,  3  gallons  No.  19,  1  gallon  4  lbs. -gum-substitute  water.  For  garancin,  add  4  gal- 
lons gum  water  instead  of  1  gallon. 

No.  25.  Drab  for  Madder,  {Machine.) — 5  gallons  No.  24,  1  quart  muriate  of  iron  at  9° 
T.,  5  gallons  4  II )s. -gum-substitute  water,  3  quarts  No.  19. 

No.  2<i.  Madder  Fawns  are  made  by  adding  to'  madder  drab  7i2,  or  so,  of  red  liquor, 
according  to  the  shade  wanted. 

No.  27.  Madder  Pvrplei^. — Iron  liquor,  mixed  with  purple  fixing  liquor,  is  diluted  with 
gum  water  according  to  the  shade  wanted.  For  instance,  No.  4  purple  for  madder 
{machine): — 1  gallon  of  iron  liquor  at  24"  T.,  2  gallons  No.  3,  4  gallons  farina  gum  water 
No.  28.  iVo.  12  purple : — 1  gallon  iron  liquor  at  24°  T.,  2  gallons  No.  3,  12  gallons 
No.  28. 

No.  28.  Dark  Farina  Gum  Water. — 10  gallons  water,  GOlljs.  dark  calcined  farina ;  boil. 

No.  29.  Garancin  Purples  are  reduced  from  iron  liquor  to  the  shade  wanted  with  the 
following  gum : — 20  lbs.  light  British  gum,  8  gallons  water,  1  gallon  purple  fixing  liquor 
No.  3 ;  boil  well,  then  take  out,  and  let  stand  3  or  4  days  before  using.  Color :  1  meas- 
ure iron  liquor,  8,  10,  20,  30,  &c.,  of  the  above  gum,  according  to  shade  wanted. 

No.  30.  Paddinri  Purples. — Reduce  to  shade  with  the  following  gum : — 6f  gallons 
water,  1  gallon  No.  3,  1  quart  logwood  liquor  at  8°  T.,  9  lbs.  flour;  boil,  and  add  5  quarts 
farina  gum  No.  28.  For  instance,  ^tO-padding  purple  for  machine: — 1  gallon  iron  liquor  at 
24°  T.,  70  gallons  of  the  aljove  gum. 

Block  colors  are  made  from  any  of  the  preceding  receipts,  by  making  them  a  little 
thinner. 

No.  31.  Alkaline  red  3Iordant. — In  a  vessel  capable  of  holding  12  gallons,  put  10  lbs. 
alum,  and  dissolve  with  5  gallons  boiling  water,  then  add  gradually  3  quarts  caustic  soda  at 
7ti°  T.,  mixed  with  1  gallon  cold  water,  till  up  with  cold  water ;  let  settle,  decant  and  repeat 
the  washing  till  the  clear  lifiuor  is  tasteless;  filter  to  a  pulp,  take  oft",  and  add  to  it  5  pints 
caustic  acid  at  70°  T.,  boil  down  to  3  gallons,  add  9  lbs.  dark  gum  substitute,  and  boil  again 
a  short  time. 

No.  32.  Pale-red  Alkaline  Mordant. — 1  measure  of  the  above  color  and  2  or  3  meas- 
ures of  dark  gum-substitute  water. 

No.  33.   10  Acid. — 1  gallon  lime  juice  at  10°  T.,  1  \h.  starch;  boil. 

No.  34.   20  Acid. — 1  gallon  lime  juice  at  20°  T.,  1  lb.  starch;   boil. 

No.  35.   30  Acid. — 1  gallon  lime  juice  at  30°  T.,  1  lb.  starch;  boil. 

No.  36.  Acid  Discharf/e. — 1  gallon  lime  juice  at  22°  T.,  1  lb.  bisulphate  of  potash; 
filter,  and  thicken  the  clear  with  1  11).  starch. 

No.  37.  Acid  Discharge. — 1  gallon  lime  juice  at  28°  T.,  2  lbs.  bisulphate  of  potash; 
filter,  and  thicken  the  clear  with  5  lbs.  dark  British  gum. 

In  the  last  two  colors,  the  bisulphate  throws  down  a  quantity  of  floceulent  matter,  which 
has  to  be  filtered  out. 

No.  38.  liescrve  Paste. — 3^  gallons  lime  juice  at  50°  T.,  2J  gallons  caustic  soda  at 
7n°  T.,  heat  to  boil,  then,  in  a  separate  vessel,  beat  up  56  lbs.  pipe-clay  with  3f  gallons 
l)oi]ing  water,  and  add  3J  gallons  6  lbs. -gum-Senegal  water;  add  to  the  other  solution,  and 
boil  20  minutes. 

No.  39.  Reserve  Paste. — 4  gallons  lime  juice  at  60°  T.,  3  gallons  caustic  soda  at  70°  T., 
boil,  and  add  48  lbs.  pipe-clay  beat  up  with  2  quarts  boiling  water,  and  4  gallons  6  lbs. -gum- 
Senegal  water;  boil  20  minutes. 

The  aliove  two  pastes  are  used  for  blocking  on  madder-work,  to  protect  the  pattern  from 
the  following  covering  shades,  which  are  raised  with  quercitron  bark,  &c.,  &c.  No.  38  is  a 
jia.stc  used  where  there  are  only  black  and  reds  to  preserve,  and  No.  39  is  used  where  there 
is  also  purple. 

Covering  Shades. 

No.  40.  5  Drab. — 1  quart  iron  liriuor  at  24°  T.,  5  quarts  water,  2^  lbs.  light  British 
gum. 

No.  41.  10  Drab. —  1  quart  iron  liquor  at  24°  T.,  10  quarts  water,  4^  lbs.  light  British 


CALICO  FEINTING.  253 

No.  42.  5  Drab. — 1  quart  iron  liquor  at  24^  T.,  1  quart  red  liquor  at  20°  T.,  5  quarts 
water,  2i  lbs.  light  British  gum. 

No.  43.  10  Drab. — 1  quart  iron  liquor  at  24'  T.,  1  quart  red  liquor  at  20°  T.,  10  quarts 
water,  5  lbs.  light  British  gum. 

No.  44.  Olive. — 2  gallons  red  liquor  at  12°  T.,  1  gallon  iron  liquor  at  14°  T.,  6  lbs. 
light  British  gum. 

No.  45.  Olive. — 3  gallons  red  liquor  at  18°  T.,  2  gallons  iron  liquor  at  8°  T.,  10  lbs. 
light  British  gum. 

No.  46.  Sac/e. — 9  quarts  red  liquor  at  9°  T.,  1  quart  iron  liquor  at  12°  T.,  4  lbs.  light 
British  gum. 

No.  47.  Sage. — 14  quarts  red  liquor  at  3°  T.,  1  pint  iron  liquor  at  12°  T.,  5^  lbs.  light 
British  gum. 

No.  48.  Chocolate  Brown. — 6  gallons  red  liquor  at  15°  T.,  1  gallon  iron  liquor  at  24' 
T.,  10^^  lbs.  light  British  gum,  3|  lbs.  flour. 

No  49.  Slate. — 3  quarts  logwood  liquor  at  8°  T.,  2  quarts  iron  liquor  at  24°  T.,  1  quart 
red  liquor  at  18°  T.,  1  quart  No.  50,  7  gallons  water,  18  lbs.  light  British  gum  ;  boil. 

No.  50.  Gall  Liquor. — 28  lbs.  ground  galls,  2  gallons  acetic  acid,  12  gallons  water ; 
stir  occasionally  for  two  days,  and  filter. 

No.  51.  Hazel. — 4  quarts  brown  No.  18,  2  quarts  bark  liquor  at  10°  T.,  1  pint  logwood 
liquor  at  12°  T.,  1  quart  cochineal  liquor  at  8°  T.,  16-oz.  measure  No.  52,  4^  quarts  6  Ibs.- 
gum-Senegal  water. 

No.  52. — 1  quart  nitrate  of  iron  at  80°  T.,  1  pint  nitrate  of  copper  at  100°  T. 

No.  53.  Standard  for  Buffs. — 10  gallons  water,  40  lbs.  copperas,  20  lbs.  brown  acetate 
of  lead  ;  stir  till  dissolved,  settle,  and  use  the  clear ;  reduced  to  shade  wanted  with  gum- 
Senegal  water. 

No.  54.  Chrome-oxide  Standard. — 3  gallons  water,  12  lbs.  bichromate  potash  ;  dissolve 
with  heat,  put  in  a  mug  of  12  gallons'  capacity,  add  3 J  pints  oil  of  vitriol  diluted  with  6 
quarts  cold  water,  add  gradually  3  lbs.  sugar ;  when  the  efifervescence  has  ceased,  boil  down 
to  3  gallons. 

No.  55.  Drab. — 5  quarts  gum-tragacanth  water,  (8  oz.  per  gallon,)  2|  quarts  No.  55, 
f  pint  cochineal  liquor  at  4°  T.,  f  pint  bark  liquor  at  8°  T. 

No.  56.  Fawn. — 1  gallon  No.  55,  2  gallons  8  oz. -gum-tragacanth  water,  -J  gallon  brown 
No.  17. 

No.  57.  Slate. — 1  gallon  No.  55,  1  gallon  8  oz. -gum-tragacanth  water. 

No.  58.  Gum-tragacajith  Water. — 10  gallons  water,  5  lbs.  gum  tragacanth  in  powder ; 
stir  occasionally  for  3  days. 

No.  59.  Fast  Blue  Standard. — 150  gallons  water,  18  lbs.  indigo  in  pulp,  24  lbs.  cop- 
peras, 28  lbs.  lime  previously  slaked ;  stir  occasionally  for  2  days,  let  settle,  and  draw  off 
the  clear  liquor,  and  to  every  10  gallons  add  1  pint  muriate-of-tin  liquor  at  120°  T. ;  filter 
on  flannel  to  a  thick  paste. 

No.  60.  Fast  Blue  for  Machine. — 1  quart  No.  60,  6  oz.  muriate-of-tin  crystals,  3  quarts 
of  water. 

No.  61.  Fast  Blue  Standard. — 4  lbs.  indigo  ground  to  pulp,  3  quarts  caustic  soda  at 
70°  T.,  3  quarts  water,  and  granulated  tin  in  excess  ;  boil  in  an  iron  pot  till  perfectly  yel- 
low, when  put  on  a  piece  of  glass. 

No.  62.  Fast  Blue.,  [Block.) — 1  quart  No.  62,  12  oz.  muriate-of-tin  crystals,  12  oz.  lime 
juice  at  60'  T.,  3  quarts  6  Ibs.-gum-Senegal  water. 

No.  63.  Fast  Green. — 1^  quarts  No.  60,  2  quarts  lead  gum  No.  64,  ^  lb.  muriate-of-tin 
crystals. 

No.  64.  Lead  Gum. — 1  gallon  hot  water,  8  lbs.  white  acetate  lead,  4  lbs.  nitrate  lead  ; 
dissolve,  and  add  1  gallon  6  Ibs.-gura-Senegal  water. 

The  course  of  operation  for  the  styles  1,  2,  and  3  above,  is  to  print  in  one  or  more  of 
the  madder  colors  ;  after  dyeing,  the  goods  are  hung  in  the  ageing  room  for  a  day  or  two, 
then  brought  to  the  dye-house.  The  first  operation  is  that  termed  dunging^  which  is  the 
same  in  principle  for  all  varieties  of  madder  or  garancin  goods,  and  as  it  is  an  operation  tiie 
careful  performance  of  which  is  of  vital  importance  to  the  success  of  the  subsequent  opera- 
tions, a  somewhat  detailed  description  of  it  will  not  be  out  of  place.  The  process  of  dung- 
ing has  for  its  object: — 

1.  Precipitating  on  the  fibre,  by  double  decomposition,  that  portion  of  the  mordant 
'which  has  escaped  decomposition  in  the  ageing  room. 

2.  Rendering  insoluble  and  inert  those  portions  of  the  mordant  which  arc  not  in  direct 
contact  with  the  fibre,  and  which,  if  allowed  to  diffuse  in  water  only,  would  fix  on  and  st;un 
the  white  or  unprinted  parts  of  the  cloth. 

3.  Softening  and  removal  of  tlie  staining  substances. 

4.  Neutralizing  the  acids  which  may  have  been  added  to  the  mordants,  and  which 
otherwise  would  dissolve  in  the  water  and  weaken  the  colors. 

5.  The  formation,  in  the  case  of  iron  mordants,  of  a  compound  of  oxide  of  iron,  and 


254  CALICO  PRmXING. 

certain  organic  or  inorganic  acids  which  will  not  become  peroxidized  beyond  a  certain 
point.  The  use  of  cow's  dung,  derived  from  India,  has  been  continued  down  to  the  present 
time,  though  for  several  years  printers  have  largely  introduced  various  substitutes. 

No  very  exact  analysis  has  been  made  of  cow  dung.  Morin's,  which  is  the  most  recent 
and  elaborate,  is  as  follows : 

Water ...        7o-00 

Vegetable  fibre 24-08 

Green  resin  and  fat  acids      -..-.-  1.52 

Uudecomposed  biliary  matter       -         .         .         .         .  0'60 

Peculiar  extractive  matter  {buhulinc)    -         -        .  1-60 

Albumen -  0"40 

Biliary  resin 8-80 

According  to  M.  Ka?chlin's  practical  knowledge  on  the  groat  scale,  it  consists  of  a  moist 
fibrous  vegetable  substance,  which  is  animalized,  and  forms  about  one-tenth  of  its  weight ; 
2,  of  albumen ;  3,  of  aninnvl  mucus ;  4,  of  a  substance  similar  to  bile ;  5,  of  muriate  of 
soda,  muriate  and  acetate  of  ammonia,  pho.sphate  of  lime,  and  other  salts ;  6,  of  benzoin  or 
musk. 

Probably  the  hot  water  in  which  the  calico-printer  diffuses  the  dung  exerts  a  powerful 
solvent  action,  and  in  proportion  as  the  uncombined  mordant  floats  in  the  bath  it  is  precip- 
itated by  the  albumen,  the  animal  mucus,  and  the  ammoniacal  salts  ;  but  there  is  reason  to 
think  that  the  fibrous  matter  in  part  animalized  or  covered  with  animal  matter,  plays  here 
the  principal  part ;  for  the  great  afifinity  of  this  substance  for  the  aluminous  salts  is  well 
known. 

It  would  appear  that  the  principal  function  of  dunging  is  to  hinder  the  uncombined 
mordant  diffused  in  the  dung  bath  from  attaching  itself  to  the  unmordanted  portion  of  the 
cloth,  as  already  observed  ;  for  if  wc  merely  wished  to  abstract  the  thickening  stuffs,  or  to 
complete  by  the  removal  of  acetic  acid  the  combination  of  the  aluminous  base  with  the 
goods,  dung  would  not  be  required,  for  hot  water  would  suffice.  In  fact,  we  may  observe, 
that  in  such  cases  the  first  pieces  passed  through  the  boiler  are  fit  for  dyeing ;  but  when  a 
certain  number  have  been  passed  through,  the  mordant  now  dissolved  in  the  water  is  at- 
tracted to  the  white  portions  of  the  cloth,  while  the  free  acid  impoverishes  the  mordanted 
parts,  so  that  they  cannot  afford  good  dyes,  and  the  blank  spaces  are  tarnished. 

It  seems  to  be  ascertained  that  the  mordant  applied  to  the  cloth  does  not  combine 
entirely  with  it  during  the  drying ;  that  this  combination  is  more  or  less  perfect  according 
to  the  strength  of  the  mordants,  and  the  circumstances  of  the  drying ;  that  the  operation 
of  dunging,  or  passing  through  hot  water,  completes  the  combination  of  the  cloth  with  the 
aluminous  base  now  insoluble  in  water ;  that  this  base  may  still  contain  a  very  minute 
quantity  of  acetic  acid  or  sulphate  of  alumina  ;  that  a  long  ebullition  in  water  impoverishes 
the  mordant  but  a  little ;  and  that  even  then  the  liquid  does  not  contain  any  perceptible 
quantity  of  acetate  or  sulphate  of  alumina. 

A  very  able  and  learncil  memoir  upon  this  subject,  by  M.  Penot,  Professor  of  Chem- 
istry, appeared  in  the  Bulletin  of  the  Society  of  Mulhausen,  in  October,  1834,  with  an  inge- 
nious commentary  upon  it,  under  the  title  of  a  Report  by  M.  Camille  Koechlin,  in  March,  1835. 
Experience  has  proved  that  dunging  is  one  of  the  most  important  steps  in  the  process 
of  calico  printing,  and  that  if  it  be  not  well  performed  the  dyeing  is  good  for  nothing. 
Before  we  can  assign  its  peculiar  function  to  the  dung  in  this  case,  we  must  know  its  com- 
position. Fresh  cow's  dung  is  commonly  neutral  when  tested  by  litmus  paper ;  but  some- 
times it  is  slightly  alkaline,  owing,  probably,  to  some  peculiarity  in  the  food  of  the  animal. 
The  total  constituents  of  100  parts  of  cow  dung  are  as  follows:  Water,  69'58  ;  bitter 
matter,  0-74  ;  sweet  substance,  0'93  ;  chlorophylle,  0-28  ;  albuminc,  0'G3  ;  muriate  of  soda, 
U-08  ;  sulphate  of  potash,  0-U5  •,  sulphate  of  lime,  0-25  ;  carbonate  of  lime,  0-24  ;  phosphate 
of  lime,  0-4() ;  carbonate  of  iron,  0"09  ;    woody  fibre,  26'39  ;  silica,  0-14  ;  loss,  0'14. 

In  dunging  calicoes,  the  excess  of  uncombined  mordant  is  in  part  attracted  by  the  solu- 
ble matters  of  the  cow's  dung,  and  forms  an  insolul)le  precipitate,  which  has  no  affinity  for 
the  cloth,  especially  in  presence  of  the  insoluble  part  of  the  dung,  which  strongly  attracts 
alumina.  The  most  important  part  which  that  insoluble  matter  plays,  is  to  seize  tlie  excess 
of  the  mordants,  in  proportion  as  they  are  dissolved  by  the  water  of  the  bath,  and  thus  to 
render  their  reaction  upon  the  cloth  impossible.  It  is  only  in  the  deposit,  therefore,  that 
the  matters  carried  off  from  the  cloth  by  the  dung  are  to  be  found. 

M.  Camille  K<pchlin  ascrilics  the  action  of  cow  dung  chiefly  to  its  albuminous  constituent 
combining  with  the  alumina  and  iron,  of  the  acetates  of  these  bases  dissolved  by  the  hot 
water  of  the  bath.  The  acids  consequently  set  free  soon  become  evident  liy  the  ti^st  of 
litmus  p;iper,  after  a  few  pieces  arc  pa.<sed  through,  and  require  to  be  got  rid  of  cither  by  a 
fresh  batii  or  by  adding  chalk  to  tlio  old  one.  The  dung  thus  serves  also  to  fix  the  bases 
on  the  elotli,  when  used  in  moderation.  It  exercises  likewise  a  deoxidating  power  on  the 
iron  mordant,  and  restores  it  to  a  state  more  fit  to  combine  with  coloring  matter.  See 
Dunging. 


CALICO  PRINTING.  255 

The  use  of  cow  dung  is  open  to  some  objections,  amongst  which  are  its  giving  a  certain 
amount  of  greenish  coloring  matter  to  the  white  mordants,  and  its  being  apt  to  vary  in  its 
constituents  from  differences  in  the  food  of  the  animals,  their  hcaltli,  &c.  ;  the  method  of 
usino"  substitutes  for  it  being  now  well  known,  and  better  colors  and  whites  being  more 
easily  obtained  from  them  than  with  dung,  it  is  probable  that  cow  dung  will  in  a  short  time 
cease  to  be  used  in  calico  printing  processes.  The  dunging  operation  ought  to  be  a  delinite 
chemical  decomposition,  which  cannot  be  the  case  with  a  variable  substance  like  dung. 
The  substitutions  for  dung  in  use  are  : — 

1.  Phosphate  of  soda  and  lime.  I  4.  Silicate  of  soda. 

2.  Arseniate  of  soda.  |  5.  Silicate  of  lime. 

3.  Arsenite  of  soda.  | 

Each  of  these  has  its  peculiar  virtues,  and  the  printer  determines  for  himself  whicli  is 
best  adapted  for  his  styles.  The  first  was  patented  by  John  Mercer,  about  1842,  and  is 
made  by  calcining  bones,  then  decomposing  them  with  sulphuric  acid,  filtering  out  the  sul- 
phate of  lime,  and,  to  the  clear  superphosphate  of  lime,  adding  carbonate  of  soda  till 
slightly  alkaline ;  the  resulting  mixture  of  phosphate  of  soda  and  phosphate  of  lime  is  dried 
down  to  a  powder ;  the  use  of  arseuiates  formed  part  of  the  same  patent.  Arsenite  of  soda 
followed  as  a  matter  of  course,  though  not  so  safe  in  use  as  phosphates  and  arseniates. 
Silicate  of  soda  was  suggested  by  Adolph  Schlieper,  of  Elberfeld,  and  patented  by  Jiiger  in 
1852.  It  is  the  ordinary  soluble  glass  dissolved  in  water.  It  is  open  to  the  objection  of 
being  too  alkaline,  hnd  requires  care  in  the  use.  The  silicate  of  lime  was  suggested  by 
Higgin  with  a  view  to  remove  this  objection.  The  silicate  of  lime  is  formed  in  the  dung 
cistern,  by  mi.\ing  silicate  of  soda  and  muriate  of  lime,  when  sparingly  soluble  silicate  of 
lime  is  formed  ;  the  quantity  in  solution  at  one  time  being  never  so  much  as  to  be  danger- 
ous, and  fresh  portions  being  dissolved  as  wanted.  Dunging  salts,  or  liquors,  are  now  made 
by  the  manufacturing  chemist,  containing  various  mixtures,  arseniates,  phosphates,  arscn- 
ites,  &c.,  which  are  adapted  for  every  variety  of  dunging.  Great  economy  of  time  and 
material  result  from  the  use  of  these  dung  substitutes.  In  some  of  the  largest  print  works, 
instead  of,  as  with  dung,  running  off"  the  spent-dung  cistern  after  passing  through  from  100 
to  200  pieces,  and  having  to  fill  again,  and  heat  to  the  proper  temperature,  it  is  found  pos- 
sible to  run  pieces  through  the  same  cistern  charged  with  substitute,  at  the  rate  of  a  piece 
per  minute  half  a  day,  and  with  light  goods  a  whole  day — before  letting  off,  of  course  occa- 
sionally adding  some  of  the  substitute,  to  make  up  for  that  saturated  by  the  mordants.  The 
dunging  process  is  always  performed  twice:  the  first  time  in  a  cistern  with  rollers ;  and  the 
second,  in  a  beck  similar  to  a  dye  beck,  washing  well  between.  The  first  is  cal\edjfi/-dn>ic/- 
inr/ ;  the  other,  second  dunging. 

The  manner  of  immersing  the  goods,  or  passing  them  through  the  dung  bath,  is  an  im- 
portant circumstance.  They  should  be  properly  extended  and  free  from  folds,  which  is 
secured  by  a  series  of  cylinders. 

The  fly-dung  cistern  is  from  10  to  12  feet  long,  i\  feet  wide,  <ind  6  or  8  feet  deep. 
The  piece  passes  alternately  over  the  upper  rollers  and  under  rollers  near  the  bottom. 
There  are  two  main  squeezing  rollers  at  one  end,  which  draw  the  cloth  through  between 
tliem.  The  immersion  should  take  place  as  fast  as  possible ;  for  the  moment  the  hot  water 
penetrates  the  mordanted  cloth,  the  acetic  acid  quits  it,  and,  therefore,  if  the  immersion 
was  made  slowly,  or  one  ply  after  another,  the  acid,  as  well  as  the  uncombined  mordant, 
become  free,  would  spread  their  influence,  and  would  have  time  to  dissolve  the  alununous 
sulr-;alts  now  combined  with  the  cloth,  whence  inequalities  and  unpoverishment  of  the  colors 
would  ensue. 

Tlie  fly-dmig  cistern  should  be  set  with  about  30  gallons  of  dung  to  1,000  gallons  of 
water ;^or,  to  the  same  quantity,  3  or  4  gallons  of  dung-substitute  liquor;  a  little  chalk  is 
added,  to  make  the  cistern  slightly  milky.  The  heat  varies  for  different  styles — from  1  .")0  F. 
to  boil.  Where  there  is  acid  discharge  or  resist,  and  the  colors  are  heavy,  fly-dunging  at 
boil  is  necessary,  to  enable  the  acid  to  cut  properly  through  the  color;  the  nearer  to  15U  V. 
that  the  bath  will  give  good  whites  at,  the  better  will  be  the  subsequent  dyed  color.  With 
cow  dung,  an  excess  of  it  is  injurious,  both  to  white  and  color;  but  witli  a  t()lera))ly  neutral 
sulwtitute,  excess  does  no  harm.  The  pieces  .shovdd  run  at  the  rate  of  Oi»  to  tio  [ler  hour. 
Oil  leaving  the  cistern,  they  are  well  winced  in  water,  and  wasJieil,  and  are  then  second 
dunged,  which  is  generally  performed  in  a  beck  similar  to  a  dye  beck,  whicli  will  be  Ibnnd 
described  further  on.  This  beck  is  set  with  about  1  (piart  of  dung-su!)stitute  rupior,  or  12 
gallons  of  dung  to  250  gallons.  From  12  to  24  ])ieces  are  put  in  together,  and  made  to 
revolve  over  a  reel  for  about  20  minutes  or  half  an  hour,  the  heat  l)eing  about  15()  F. 
They  are  then  well  washed,  and  are  ready  for  dyeing.  Tiiis  second  dunging  is  principally 
for  the  purpose  of  removing  the  thickening  substance  from  tlie  dotli,  anil  it  ^^h()^ld  fet'l 
quite  soft  when  well  done.  An  improved  method  of  dunging  ailopted  by  some  extensive; 
firms  consists  in  arranging  a  fly-dung  cistern,  a  wince  pit,  a  machine  similar  to  the  blcaclier's 
washing  machine,  and  containing  the  second  dunging  solution  and  one  of  the  dye-house 


256 


CALICO  FEINTING. 


washino'  machines  all  in  a  line ;  the  pieces,  being  then  stitched  end  to  end,  are  drawn  through 
the  series;  first,  extended  and  free  from  folds,  through  the  fly-dung  cistern;  thence  drop- 
ping into  water  in  the  pit ;  from  that  being  worked  spirally  from  end  to  end  of  the  second 
dunging  vessel,  which  runs  at  such  a  speed  that  one  piece  is  about  15  minutes  in  traversing 
it;  from  that  into  a  water  pit  again,  and  finally,  spirally,  through  the  washing  machine, 
when  they  are  ready  for  dyeing.  By  this  arrangement  the  process  is  a  continuous  one,  and 
little  labor  is  required.  The  drawing  rollers  on  the  fly-dung  cistern  are  worked  by  a  strap 
from  a  shaft.  On  the  thorough  cleansing  from  loosely  attached  mordant,  and  especially 
thickening,  depends  a  good  deal  of  the  success  of  the  dyeing,  and  this  process  is  one  that 
requires  to  be  carefully  attended  to. 

The  washing  processes  in  the  dye  house  have  undergone  great  modifications  within  the 
last  few  years.  Formerly,  in  washing,  the  old  dash  wheels  were  exclusively  employed,  but 
now  are  "considered  fiir  too  slow,  and  expensive  in  labor,  and  are  nearly  abolished,  being 
substituted  by  various  washing  machines.  A  great  number  of  machines  have  been  invented, 
which  all  have  their  admirers.  Three,  which  have  been  found  very  efficacious,  are  here 
given. 

Fiq.  129  is  a  perspective  view,  axiAfig.  130  a  section  of  the  machine  patented  by  Mather 
and  Piatt.  The  pieces,  fastened  end  to  end,  are  run  spirally  through  the  machine,  being 
subjected  to  the  action  of  the  beams  or  beaters  D  d,  whilst  lying  in  loose  folds  on  the  large 
wooden  roller  c. 

129 


130 


CALICO  PKINXma. 


257 


Fig.  131  is  a  machine  patented  by  Whitaker,  and  possesses  the  merit  of  great  sim- 
plicity with  comparatively  small  first  cost,  together  with  great  efficiency.  The  invention 
consists  of  a  peculiar  arrangement  of  the  material  to  be  washed,  by  which,  instead  of  it 
moving  in  one  continuous  direction,  it  is  made  to  cross  in  its  traverse ;  and  by  one  part 
being  in  constant  contact  with  another  part,  a  powerful  rubbing  action  is  continually  kept 
up,  thereby  washing  or  cleansing  the  cloth  or  material  more  effectually  than  can  be  done  by 
the  usual  method  of  merely  passing  it  between  presser  rollers. 


c 

1 

or 

) 

132 

/ 

(   o 

'■  y/^y^^ 

A 

iL^  y      -^^/^     ^  ^, 

^^^ 

--^-     <A0       j-pe^ Jl^^"^ 

I 

B 

Fig.  131  is  an  end  view  of  this  washing  machine,  and  jig.  132  an  end  view  with  the 
frame  side  removed,  to  show  the  improved  arrangement,     a  and  b  represent  two  stones, 
upon  which  the  machine  is  fixed ;  c  is  the  frame,  which  forms  sides  for  the  water  cistern, 
Vol.  III.— 17 


258  CALICO  PRINTING. 

and  also  the  journals,  or  bearings,  of  the  bowls  d,  e,  /,  which  pass  from  one  side  to  the 
other,  as  in  ordinary  washing  machines;  p  is  a  peg  rail,  with  the  pegs  h  passing  across  the 
machine ;  i  is  the  outlet  for  spent  water ;  J,  a  wooden  frame  surrounding  the  whole  of  the 
water  or  liquor  in  the  cistern  k,  which  is  open  at  the  top  end,  and  communicates  with  the 
space  for  over  water.  The  machine  is  put  in  motion  by  spur  wheels,  represented  by  the 
dotted  circles  /,  »«,  and  «,  mfg.  131;  the  wheel  m  is  put  upon  the  main  shaft  or  shafts 
connecting  with  the  moving  power.  The  piece  o  is  introduced  into  the  machine  at  that  end 
where  the  outlet  for  water  is  placed,  and  threads  through  the  peg  rail  progressively  to  the 
other  end  of  the  machine,  where  the  fresh  water  is  introduced  just  upon  the  cloth  or  material 
as  it  leavcB.  When  the  machine  is  in  motion,  the  cloth  moves  on  progressively,  and  is 
caused  to  vibrate  by  the  varying  dimensions  of  the  square  bowl,  which  motion  rubs  one 
part  of  the  material  against  another  part,  by  being  crossed  once  on  each  side  of  the  square 
bowl,  and  washes  in  the  same  manner  as  a  woman  would  do  in  ordinary  domestic  washing. 
And  it  will  be  observed  that  when  a  corner  of  the  square  bowl  is  at  the  bottom,  the  mateiial 
is  then  below  the  surface  of  the  water,  and  when  the  fide  of  the  square  bowl  is  at  the  bot- 
tom the  cloth  is  above  the  surface ;  thus,  for  each  revolution  of  the  square  bowl,  the  cloth 
is  plunged  four  times,  which  action  encloses  air  within  the  folded  material,  and  opens  it 
out  between  the  peg  rail  and  square  bowls,  eometimes  as  large  as  a  man's  hat.  The  water 
is  preserved  clean  at  that  end  of  the  machine  where  the  material  leaves  it,  by  its  being 
brought  in  there,  and  allowed  to  escape  where  the  dirty  material  enters,  and  by  the  shallow- 
ness of  the  water  cistern  the  water  is  constantly  being  renewed. 

Fif}.  133  represents  the  machine  patented  by  Mr.  David  Crawford  of  the  Barrowfield 
Printworks.  It  is  said  to  answer  well  for  all  sorts  of  fabrics,  the  finest  muslins  not  being 
torn  by  this,  as  is  the  case  with  most  washing  machines.  This  machine  consists  of  a  rec- 
tangular frame,  fitted  up  with  rollers,  dashboards,  a  dashing  frame  and  driving  gearing. 
The  frame  is  divided  into  a  series  of  stories  or  flats,  one  above  another,  like  the  floors  of  a 
house,  each  flat  having  a  dashboard  or  a  fixed  platform  divided  down  the  centre,  towards 
which  division-line  each  half  inclines  downwards.  The  goods  in  a  continuous  length-like 
form  are  passed  first  of  all  round  a  taking-in  roller,  which  directs  the  cloth  round  a  long 
horizontal  roller  of  considerable  diameter,  which  runs  in  bearings  at  one  side  or  end  of  the 
lowest  of  the  series ;  the  fabric  passes  round  this  roller,  and  there  proceeds  horizontally 
along  and  through  the  flat  at  that  level,  passing  in  its  way  through  a  vertical  traversing 
frame,  which  works  between  the  contiguous  edges  of  the  platforms  or  dashboards  of  all  the 
flats  where  the  boards  are  divided  as  before  explained.  In  the  centre,  at  the  opposite  end 
of  the  flat,  there  is  a  corresponding  horizontal  roller,  round  which  the  fabric  passes,  return- 
ing through  the  flat  and  through  the  vertical  traversing  frame  to  the  first  roller ;  the  fabric 
passes  again  round  this  roller  and  again  through  the  flat,  and  so  on  until  the  required  num- 
ber of  cros-sings  and  re-crossings  has  been  completed.  The  rollers  are  geared  together  so 
as  to  be  driven  simultaneously  to  carry  the  fabric  along  back  and  forward  over  these  rolleis 
and  through  the  flats,  whilst  jets  of  water  or  other  fluids  are  allowed  to  fall  upon  the  fabric 
in  its  passage,  and  whilst  the  vertical  traversing  frame  dashes  the  cloths  with  rapidity  and 
severity  upon  the  dashboards  beneath ;  the  traversing  frame  being  worked  by  an  overhead 
crank,  or  by  any  other  reciprocator.  As  the  cleansing  liquid  falls  down  it  is  received  upon 
the  dashboards  l)eneatli,  and  until  it  pours  ofi"  at  the  centre:  the  striking  action  causes  the 
liquid  to  be  well  forced  into  the  falirie.  When  the  water  falls  away  at  the  centre  it  is  re- 
ceived by  a  bottom  duct  and  conveyed  away  to  a  bottom  side-chamber,  into  which  chamber 
the  fabric,  as  primarily  washed  in  the  bottom  flat,  is  first  of  all  delivered  from  its  rollers  to 
the  next  flat  on  the  series,  where  it  is  treated  in  a  precisely  similar  manner;  and  this  routine 
is  continued  throughout  the  whole  of  the  flats  until  the  fabric  finally  emerges  from  the  top 
of  one  of  the  series  in  its  completely  cleansed  condition.  Each  flat  is  supplied  with  jets  of 
water,  and  it  is  obvious  that  as  the  fabric  passes  through  and  beneath  these  jets,  and  is  vio- 
lently struck  upon  the  da.sliboards,  a  most  powerful  washing  and  cleansing  action  is  secured : 
provision  is  made  for  varying  the  length  of  traverse  of  the  vertical  dashing  frame  and  the 
rapidity  of  its  traverses. 

Fifj.  133  on  the  drawings  is  a  sectional  eleyation,  and  /Tr;.  134  is  an  end  view  correspond- 
ing, as  looking  on  the  driving  gear,  and  the  taking  in  and  delivering  movements.  The 
two  cast-iron  side  standards,  a,  form  the  main  frame.  These  standards  carry  internal 
bracket  flanges  for  supporting  the  four  dashboard  floors  C.  All  the  driving  movements  are 
actuated  from  a  bottom  horizontal  shaft,  carrying  a  bevel  wheel  q,  in  gear  with  a  correspond- 
ing wheel  R,  fast  on  the  lower  end  of  a  vertical  shaft  s.  This  shaft,  by  means  of  the  two 
pairs  of  bevel  wheels  w,  drives  the  two  large  end  rollers  n,  carried  in  end  bearings  ex- 
ternal to  the  main  framing.  The  lower  end  of  the  shaft  rests  in  a  footstep  bearing  on  the 
floor,  whilst  the  upper  end  is  supported  in  a  collar  bearing,  carried  by  a  bracket  t,  bolted 
to  the  frame.  At  this  part,  a  third  pair  of  bevel  wheels,  u,  forms  the  driving  communica- 
tion between  the  shaft  and  the  end  conical  roller  pulley  i.,  working  the  dashing  movement. 
All  the  stories  or  dashboards  of  the  machine  are  plentifully  supplied  with  water  by  the  pipe 
D,  having  a  regulating  stop-cock  at  its  upper  or  lower  branch.     From  this  main  pipe,  cross 


CALICO  FEINTING. 


259 


branches  d,  pass  into  and  through  all  the  divisions  discharging  the  water  by  the  jets  upon 
the  goods  passing  through  the  machine.  A  guide  ring  is  attached  to  the  ceiling  of  the 
workshop  t,  for  the  passing  through  of  the  goods  b.  From  this  ring,  the  line  of  goods 
passes  in  the  direction  of  the  arrow,  down  and  round  a  guide  roller  arrangement,  so  as  to 
be  directed  through  the  water  in  the  small  bottom  chamber  z.  On  leaving  this  chamber 
the  fabric  passes  through  a  delph  eye  in  the  end  boarding  of  the  machine,  and  thus  reaches 
the  lowest  division  of  the  series.  As  it  continues  its  course  it  passes  between  the  lowest 
pair  of  rollers  or  bars  e,  of  the  vertical  traversing  frame  r,  which  gives  the  necessary 
dashing  action,  then  proceeds,  guided  by  the  pin  o  round  the  bottom  back  roller  n,  corre- 
sponding to  the  lowest  of  the  front  rollers  n.  On  rounding  this  roller,  the  fabric  repeats 
the  circuit  already  described  three  or  more  times,  as  indicated  by  the  turns  upon  the  roller, 
in  the  view  oi  fiij.  2.  After  the  completion  of  this  traverse,  the  line  of  fabric  ascends,  as 
shown  by  the  arrow  being  drawn  out  between  the  nipping  roller  p  and  the  bottom  roller  n. 
The  fabric  again  ascends  for  the  last  time  and  passes  through  the  third  and  fourth  divisions, 
being  delivered  in  a  cleansed  condition  at  g.  The  dashing  action,  as  already  explained,  is 
worked  from  the  conical  pulley  J,  the  spindle  of  which  runs  in  pedestal  bearings  imme- 
diately above  the  centre  of  the  machine.  A  sliding  rod,  with  a  double  strap  fork  m,  is 
fitted  up  for  enabling  the  attendant  to  set  the  drawing  belt  k,  at  any  part  of  the  conical 
pulley^  so  as  to  vary  the  rate  of  revolution  of  the  driving  pulley  J,  that  of  l  being  constant. 
The  spindle  of  the  pulley  j  carries  at  each  end  an  adjustable  disc  crank  i,  the  face  slots  of 
these  discs  having  crank  stud-pins  set  in  them  for  workingf^the  upper  ends  of  the  pendant 
connecting  rods  ii.  The  lower  ends  of  these  rods  are  similarly  jointed  to  stud  g  upon  the 
opposite  edges  of  the  traversing  dashing  frame  r.  These  studs  work  through  vertical  slots 
in  the  main  standards,  and  as  tlae  disc  crank  i  revolves  at  a  rapid  rate,  it  follows  that  the 
corresponding  rapid  traverse  of  the  dashing  frame  energetically  dashes  the  lines  of  fabric 
passing  between  its  rollers  upon  the  several  dashboards  of  the  machine.  The  cleansing 
water  falling  from  the  several  jets,  is  conducted  from  flat  to  flat  by  conductors  y,  thoroughly 
washes  the  goods,  whilst  this  is  going  on,  and  it  finally  falls  through  the  central  openings  in 
the  dashboards,  and  is  received  into  the  bottom  central  trough,  whence  it  flowe  away  by  the 
duct,  and  is  delivered  into  the  chamber  z.  The  lever  x  in  connection  with  pulley  p  is  to 
enable  the  attendant  to  raise  up  pulley  p  in  threading  the  machine.  This  machine  is  beau- 
tifully adapted  for  bleaching  purposes,  as  from  the  peculiarity  of  its  action  it  answers  as  a 

13a 


^^mmmmmm/MmMMiiiJiiiii^^ 


perfect  Bleaching  Machine  in  itself.  The  slots,  grooves  in  the  disc  cranks,  afford  a  ready 
means  of  varying  the  length  of  the  traverse  of  the  dashing  frame ;  and  this  adjustment, 
coupled  with  that  of  the  rate  of  revolution  of  the  central  conical  roller,  affords  the  greatest 
possible  nicety  of  adjustment  of  the  powers  of  the  machine,  which  the  manufacturer, 
bleacher,  or  finisher  can  ever  require,  either  for  light  or  heavy  goods. 


260 


CALICO  PRINTING. 
134 


Vx>i>:\>\\. 


.\.,«:s\^ 


Up  to  this  point  there  is  scarcely  any  difference  in  the  operations  on  pieces  destined  for 
styles  1  a,  b,  &;c.,  and  2.  Those  intended  for  dyeing  with  madder  are  printed  in  stronger 
^colors  than  those  for  dyeing  with  garancin,  since  the  soaping  process  reduces  the  strength 
of  color  considerably,  and  garancin  colors  undergo  no  severe  treatment  after  dyeing.  The 
general  process  of  dyeing  is  thus  performed : — 

Fig.  135  represents  a  front  elevation  of  a  pair  of  dye  becks,  with  automatic  winch  reel, 
and_/?V/.  136  is  an  end  elevation  of  one  of  them.  The  drawing  is  kindly  supplied  by  Messrs. 
Mather  and  Piatt,  of  Salford.  a  a  is  a  cast-iron  cistern,  8  feet  long  by  4  feet  deep  by  3 
feet  wide,  with  curved  bottom ;  brackets  b  b  are  cast  on  the  ends  to  support  the  cistern  on 

ir;.3 


CALICO  PRINTING. 


261 


136 


the  stone  foundation.  The  beck  is  fixed  over  a  channel  c,  which  commxinicates  with  the 
system  of  drains  which  carry  away  the  waste  liquors  into  the  river.  There  are  two  holes 
in  the  curved  bottom — one  at  each  end — which,  when  the  beck  is  in  use,  are  stopped  with 
movable  plugs ;  one  of  these  holes  communicates  direct  with  the  drain  and  the  other  with 
a  trough  D,  which  communicates  with  a  pit  out- 
side the  dye-house,  and  where  the  spent  madder 
can  be  run  for  the  purpose  of  making  into  garan- 
ceux.  E  is  a  water  pipe,  with  a  branch  into 
each  beck,  with  a  screw  tap  attached ;  f  is  a 
main  steam  pipe,  which  divides  into  the  branches 
G,  furnished  with  valves  at  H ;  the  pipes  G  sub- 
divide in  branches  i,  one  of  which  goes  down 
each  end  of  the  dye  beck,  the  perforated  pipe  k, 
which  traverses  the  beck  from  end  to  end,  con- 
necting them ;  a  perforated  iron  diaphragm  is 
placed  across  the  beck  from  end  to  end ;  above 
this  is  a  strong  rod  m,  from  end  to  end,  carrying 
pieces  n  projecting  at  right  angles  from  it. 
Bolted  on  the  ends  of  the  dye  beck  is  the  frame- 
work o,  which  carries  the  bearings  of  the  shaft 
Q  of  the  wincli  reel ;  keyed  on  the  shaft  are 
three  sets  of  cast-iron  arms  r,  which  terminate 
in  forks,  in  which  fit  the  spars  s ;  the  reel  is 
boarded  between  the  spars,  as  at  t.  The  frame- 
work 0  of  the  two  dye  becks  is  connected  by 
the  piece  u,  which  carries  the  bearings  of  the 
short  shaft  v,  on  which  is  keyed  one  of  a  pair 
of  mitre  wheels  w  w ;  there  are  sliding  catch 
boxes  s  X  on  this  shaft,  which  revolve  with  it ; 
there  are  corresponding  catch  boxes  keyed  on 
the  ends  of  the  shaft  q  ;  the  connecting  piece  u 
carries  also  the  pillar  p,  which  carries  the  bear- 
ings of  the  vertical  shafts  y,  and  also  of  the 
horizontal  shaft  z ;  keyed  on  the  shafts  Y  and  z 

are  bevel  wheels  a  a,  and  at  the  bottom  of  shaft  t,  the  mitre  wheel  w.  Permanent  motion 
being  given  the  shaft  v  v,  by  this  gearing,  either  of  the  reels  can  be  put  in  motion  or  stopped 
by  the  catch  boxes  x  x,  worked  by  lever  bandies,  in  or  out  of  the  catch  boxes  on  the  ends 
of  the  reels.  In  working  the  becks,  two  pieces  are  knotted  end  to  end,  and  each  length 
passed  over  the  reel  down  between  two  of  the  studs  N,  under  the  steam  pipe  k,  up  behind 
the  diaphragm  l,  being  then  knotted  together  so  as  to  form  an  endless  w-eb,  the  bulk  of 
which  lies  on  the  bottom  of  the  beck.  The  drawing  shows  a  beck  adapted  for  15  lengths 
of  2  pieces  each,  or  30  pieces.  About  200  gallons  of  water  are  put  in  the  beck  before  the 
pieces  are  put  in ;  and,  after  the  pieces,  the  dye  stuff  is  added,  the  reel  set  in  motion,  and 
the  steam  gently  turned  on ;  from  the  steam  going  in  at  each  end,  the  beck  is  uniformly 
heated ;  the  heat  is  then  gradually  raised  to  boil,  generally  in  about  two  hours,  the  pieces 
continually  revolving  with  the  reel  so  as  to  bring  each  portion  successively  into  the  air,  agi- 
tating the  dyeing  materials  at  the  same  time.  When  the  dyeing  is  finished,  the  steam  is 
shut  off,  the  knots  untied,  and  the  pieces  pulled  over  into  a  pit  of  water  surrounded  by  a 
winch  reel,  which  is  .always  placed  behind  every  dye  beck.  After  wincing  in  this,  the  pieces 
are  fastened  together  again,  and  put  through  the  washing  machine  two  or  three  times ;  they 
then  are  ready  for  the  subsequent  operations.  Maddered  goods,  on  issuing  from  the  dye 
beck,  are  far  from  possessing  the  beauty  that  they  afterwards  show,  the  colors  are  dull  and 
heavy,  and  the  white  part  stained  with  a  reddish  shade ;  various  clearings  are  required,  in 
wliich  soap  plays  a  principal  part.  Garancined  goods  show  pretty  nearly  the  color  they  arc 
intended  to  be ;  but  as  tlie  white  is  ako  stained,  a  peculiar  clearing  is  given  them  \\hich 
will  be  described  further  on.  Madder  goods  are  cleared  with  soap  in  a  beck  similar  to  a  dye 
beck.  They  receive  generally  two  soapings  of  about  half  an  hour,  with  from  J  to  +  lb.  of 
SDap  per  piece  each  time,  washing  between.  If  the  white  is  not  sufficiently  good,  the  pieces 
are  spread  out  on  the  grass  for  a  day  or  two,  and  are  afterwards  winced  in  hot  water  to 
which  a  little  solution  of  chloride  of  lime  or  soda  is  added.  They  are  then  washed  and 
dried.  Chintz  work  is  dyed  with  from  1  lb.  to  5  lbs.  madder  per  piece  of  30  yards,  accord- 
ing to  the  pattern;  generally,  a  little  chalk  is  added,  and  if  there  is  no  purjjle  in  the  ))at- 
tern,  some  sumac,  which  is  found  to  economize  madder,  t)ut  will  not  do  where  there  is  pur- 
ple, the  shade  of  which  it  deadens.  Pieces  of  any  style,  after  undergoing  the  final  proces.'s, 
are  passed  through  a  pair  of  squeezing  rollers,  or  put  in  the  hydro-extractor,  when  the  moist- 
ure is  driven  out  by  centrifugal  force,  (see  Hydro-extractor  ;)  they  ar(^hen  dried  on  the 
cylinder  drying  machine. 


262 


CALICO  FEINTING. 


Plate  Purple  is  a  style  composed  of  black  and  one  or  more  shades  of  purple  only,  and 
requires  a  little  different  treatment.  Print  in  black  No.  4,  dark  purple  to  shade  No.  27 
and  acid,  say  No.  35,  cover  pad  in  pale  purple,  No.  30,  age.  Fly  dung  at  170°  F.,  second 
dung  at  105°  F.  half  an  hour;  wash  and  dye  with  ground  Turkey  madder  root,  giving  '/io 
of  its  weight  in  chalk,  and  3  quarts  of  bone  size  to  the  beck  ;  bring  to  175°  F.  in  2  hours, 
and  keep  at  175°  F.  half  an  hour ;  wash  well  and  soap  15  pieces,  ^,  30  yards,  half  an  hour 
at  boil  with  5  lbs.  soap  to  15  pieces;  wash  well  and  wince  5  minutes  at  140°  F.  with  2 
quarts  chloride  of  lime  liquor  at  8°  F.  to  300  gallons ;  wince  and  soap  again  at  boil  half  an 
hour  with  3  lbs.  soap  to  15  pieces ;  wash  and  wince  5  minutes  in  4  quarts  chloride  of  lime 
at  8°  F.  and  2  lbs.  carbonate  of  soda  crystals  to  200  gallons  water ;  at  160°  F.  well  wash 
and  dry. 

In  this  style,  as  in  any  where  there  is  severe  soaping,  it  is  necessary  to  give  a  slight  ex- 
cess of  madder  in  the  dye,  so  as  to  ensure  perfect  saturation — if  this  is  not  done,  the  color 
speedily  degrades,  and  becomes  impoverished.  It  may  be  observed  here,  that  the  style 
plates  are  such  as  formerly  were  printed  by  the  plate  or  flat  press,  and  are  generally  small 
patterns,  with  padded  or  well  covered  grounds,  the  colors  being  few,  and  frequently  only 
different  shades  of  one  color. 

Plate  Pinks  or  Swiss  Phiks — a  style  imported  from  Switzerland,  consisting  of  various 
shades  of  red  and  delicate  pinks,  produced  as  follows  : — Print  in  No.  6  with  second  or  third 
shades,  as  No.  7 — acid  No.  34  may  be  also  printed,  and  a  very  pale  shade  of  red  covered, 
aged  two  or  three  days,  dunged  at  1G0°  F. — if  dung  substitute  is  used,  care  must  be  taken 
to  use  one  that  is  not  caustic  from  free  alkali ;  the  dyeing  must  be  done  with  the  finest 
quality  of  French  or  Turkey  madder.  The  pieces  must  have  sufficient  madder  allowed  to 
overdye  them,  or  dye  a  heavy  brownish  red.  For  a  full  plate  pink  on  -J  cloth,  from  4  to  6 
lbs.  of  French  madder  will  be  required.  About  5  i)er  cent,  of  chalk  may  be  added  to  the 
dye  where  the  water  is  soft.  The  heat  should  be  i-aised  to  150°  F.  in  2  hours,  and  kept  at 
that  heat  half  an  hour.  It  is  necessary  to  keep  the  heat  low  in  dyeing  French  pinks,  to 
prevent  the  impurities  from  fixing  on  the  mordants,  as  only  the  very  finest  portion  of  the 
coloring  matter  must  be  fixed — after  dyeing,  the  pieces  are  well  washed  and  soaped  with 
about  half  a  pound  of  soap  per  piece  in  a  beck  at  140°  F.  for  half  an  hour,  they  are  then  well 
washed  and  entered  in  a  beck  with  cold  water,  to  which  has  been  added  sufficient  oxymuri- 
ate  of  tin  or  sulphuric  acid  to  make  faintly  sour,  a  little  steam  is  turned  on,  and  the  heat 
raised  to  about  120°  F.  in  half  an  hour;  the  colors  which  on  entering  the  beck  were  full 
shades  of  red,  gradually  assume  an  orange  tint,  and  when  of  a  bright  orange  color,  the 
pieces  are  taken  out,  and  winced  in  water.  This  operation,  termed  cuttinc/,  is  the  one  that 
decides  the  depth  of  tint  in  the  finished  piece.  The  longer  the  pieces  are  kept  in  the  beck, 
and  the  greater  the  heat,  the  paler  and  more  delicate  the  shade  of  pink  obtained.  Afttr 
this  treatment  they  are  put  in  a  beck  with  soap,  and  boiled  for  an  hour,  taken  out,  washed 
well,  and  put  in  a  strong  pan  charged  with  soap  and  water,  the  lid  screwed  down,  and  boiled 
at  a  pressure  of  two  atmospheres,  either  by  direct  fire  or  high-pressure  steam,  for  two  or 
three  hours,  then  taken  out,  washed,  and  put  in  a  beck  with  water  at  1C0°  F.,  charged  with 
a  little  hypochlorite  of  soda :  they  stay  in  this  about  ten  minutes,  and  are  then  washed  and 
dried.  In  some  print  works,  after  the  high  pressure  boil,  the  pieces  are  spread  out  on  the 
grass  for  a  night  or  two,  and  then  cleared  in  hypochlorite,  &c.  The  use  of  the  acid  here  is 
not  very  clear,  it  probably  completely  purifies  the  color  from  iron  which  may  have  been  in 
the  mordant,  but  it  also  seems  to  render  the  combination  of  alumina,  tin,  lime,  coloring 
matter,  and  fat  acid  a  definite  one  by  removing  a  small  quantity  of  the  mordant.  The  French 
chemists  assert,  that,  after  the  final  process,  a  definite  atomic  compound  of  lime  and  alu- 
mina, coloring  matter,  and  fat  acid  remains. 

The  quality  of  the  soap  used  by  printers  is  of  great  importance.  It  is  made  for  them 
specially  from  palm  oil,  and  requires  to  be  as  neutral  an  oleo-stearate  as  possible ;  an  alka- 
line soap  like  domestic  soap  would  inipovcrish  and  degrade  the  shades. 

The  soaping  process  has  a  twofold  action  : — 

To  clear  the  white  by  decomposing  the  compound  of  lime  and  coloring  matter  which 
forms  the  stain  ;  this  it  does  by  double  decomposition,  forming  oleo-stearate  of  lime,  which 
dissolves  or  forms  an  emulsion  with  the  excess  of  soap  ;  and  a  compound  of  soda  and  color- 
ing matter,  which  dissolves.  In  its  action  on  the  dyed  parts,  it  probably  first  removes  resi- 
nous and  other  impurities  which  are  loosely  held  by  the  mordant,  and  secondly  gives  up  a 
portion  of  its  fat  acid  to  the  dyed  parts — the  resinous  acids  or  possibly  phosphoric  acid  from 
the  dyed  parts,  by  combining  with  the  soda,  setting  free  fat  acid  for  this  purpose. 

Second  Style  :  Garancin. 
Almost  all  the  madder  styles  are  imitated  by  dyeing  with  garancin,  a  concentrated  prep- 
aration of  madder  (see  Maddk.r)  which  dyes  fine  brilliant  colors  at  once,  not  requiring  to 
be  soaped  to  develop  the  shades,  but  not  possessing  the  extreme  solidity  of  madder  color. 
Garancin  dyeing  is  the  most  economical  way  of  using  madder,  since  more  coloring  matter  is 
obtained  in  this  way  than  by  using  madder  direct,  and  consequently  garancin  is  principally 


CALICO  FEINTING.  .  263 

used  for  full  heavy  colors,  which,  if  dyed  with  madder  and  eoaped,  would  be,  to  a  certain 
extent,  abraded,  and  not  stand  so  finely  on  the^surface  of  the  cloth.  Chocolate  grounds, 
black,  red,  and  chocolate,  with  brown  or  drab,  dark  purple  plates,  black  and  scarlet  ground, 
are  thus  dyed  ;  in  short,  wherever  the  pattern  is  very  full,  and  cheapness  essential,  garancin 
is  resorted  to.  The  colors  or  mordants  for  garancin  are  usually  about  two-thirds  of  the 
strength  of  similar  colors  for  madder,  (see  the  list  of  colors,)  the  ageing  and  dunging,  &c. 
are  the  same  as  for  madder  ;  the  dyeing  is  performed  in  the  same  manner,  using  from  one- 
fourth  to  one-third  the  quantity  that  would  be  used  of  madder.  A  little  chalk  is  also  added 
where  the  water  is  soft ;  and  the  dyeing  is  commenced  at  110°  F.,  and  carried  to  185"  F., 
or  190'  F.  in  two  hours  ;  then  got  out  and  well  washed  and  rinsed  in  water  at  140°  F.,  in  a 
beck,  for  10  minutes,  then  squeezed  and  dried.  The  white  is  always  stained  a  little,  though 
not  to  the  same  extent  as  in  maddered  goods,  and  this  slight  stain  is  removed  by  a  process 
peculiar  to  garancin  goods.  In  front  of  an  ordinary  cylinder  drying  machine,  is  placed  a 
padding  apparatus,  and  between  it  and  the  drying  machine  is  placed  a  chest  provided  with 
a  few  rollers  at  top  and  bottom  ;  this  chest  is  covered  by  a  lid,  which  has  at  each  end  a  slit, 
by  which  the  piece  enters  and  issues ;  a  perforated  steam  pipe  at  the  bottom  of  the  chest 
allows  steam  to  blow  freely  in.  The  padding  machine  is  charged  with  solution  of  hypo- 
chlorite of  lime,  at  from  ^°  to  2J°  Twaddell's  hydrometer,  according  to  the  depth  of  the 
stain  on  the  white  ;  the  pieces  are  padded  in  this  liquor,  squeezed  out  by  the  bowls,  and 
then  run  into  the  steaming  chest,  which  is  of  such  a  size,  that  any  given  point  on  the  piece 
is  about  i  minute  in  passing  through  it ;  on  leaving  this  chest,  the  pieces  pass  through 
water,  or  water  is  spirted  on  from  a  perforated  pipe  ;  after  again  passing  through  squeezing 
rollers,  they  proceed  on  to  the  cylinders  of  the  drying  machine,  on  leaving  which  the  white 
is  found  to  be  perfectly  bleached  and  the  colors  brightened. 

There  are  several  varieties  of  garancin,  each  adapted  to  particular  styles.  For  dark  full 
black,  chocolate,  and  red,  with  brown  or  drab,  and  where  there  is  no  purple,  a  garancin 
termed  chocolate  garancin,  made  from  the  commonest  descriptions  of  madder,  answers  very 
well,  and  this  class  of  goods  is  usually  dyed  with  chocolate  garancin,  assisted  by  small  quan- 
tities of  sumac,  quercitron  bark,  and  peachwood,  which  additions  give  full  rich  shades. 
Where  there  is  purple,  none  of  these  adjuncts  can  be  used,  and  the  garancin  requires  to  be 
made  from  a  superior  description  of  madder.  Within  the  lust  three  or  four  years,  great  im- 
provements in  the  manufacture  of  purple  garancins  have  been  made.  The  Alizarin,  patented 
by  Pincoff  and  Schunck,  has  the  property  of  dyeing  at  once  purples  as  pure  as  the  finest 
soaped  madder  shades ;  it  has  the  disadvantage  of  not  dyeing  good  black  and  reds,  and 
wh^n  these  colors  are  freely  introduced  along  with  purple,  an  admixture  of  ordinary  purple 
garancin  is  required,  the  general  effect  being  still  very  good,  but  the  purple  not  quite  so 
fine.  The  garancin  patented  by  Higgin  dyes  very  good  purple,  with  black,  chocolate,  and 
red  also.  Both  these  improved  garancins  stain  the  white  grounds  very  little,  and  produce 
considerably  faster  work  than  the  ordinary  garancins  ;  the  goods  may  even  be  soaped  to  a 
considerable  extent.  A  garancin  that  will  bear  as  severe  soaping  as  madder,  or  a  method 
of  so  dyeing  with  garancin  as  to  produce  the  same  effect,  is  still  a  desideratum.  When  this 
can  be  accomplished,  there  will  be  an  end  of  dyeing  with  madder,  which  will  be  considered 
a  raw  material,  and  be  all  manufactured  into  garancin. 

Garanceux. — In  ordinary  madder  dyeing,  the  madder  can  never  be  made  to  give  up  all 
its  coloring  matter.;  when  all  coloring  matter  soluble  in  water  has  been- exhausted,  there  still 
remains  about  a  quarter  of  the  whole  quantity,  combined  with  lime,  and  mixed  with  the 
woody  fibre.  This  madder  is  turned  to  account  by  converting  it  into  garancin,  or,  as  this 
preparation  is  called,  garanceux.  The  spent  madder  is  run  off"  into  a  pit  outside  the  dye- 
house,  where  it  is  mixed  with  a  small  quantity  of  sulphuric  acid,  to  precipitate  any  coloring 
matter  in  solution.  It  is  then  allowed  to  drain  dry  ;  removed  from  the  pit,  it  is  boiled  in  a 
leaden  vessel,  with  more  sulphuric  acid,  for  several  hours,  then  washed  on  a  filter  till  free 
from  acid,  and,  after  draining,  is  ready  for  use>  It  dyes  to  about  one-third  the  strength  of 
ordinary  chocolate  garancin,  and  is  principally  used  for  the  commoner  garancin  styles.  Mr. 
John  Lightfoot,  of  Accrington,  has  patented  an  improvement  in  the  ordinary  process  of 
making  garanceux.  He  recommends  large  vats  to  be  provided,  two  or  more  in  number, 
each  sufficiently  large  to  contain  all  the  waste  dyeing  liquor  produced  in  the  dye-house  in 
one  day,  and  so  arranged  that  the  liquor  runs  from  the  dyebecks  into  them  ;  at  a  certain 
point  in  the  trough  that  conducts  the  liquor  to  the  vats,  is  placed  a  lead  cistern  with  a  valve 
and  perforated  bottom  ;  this  cistern  holds  a  regulated  quantity  of  concentrated  sulphuric 
acid,  and  whenever  a  dyebeck  is  let  off"  and  the  liquor  flowing  down  the  trough,  a  ciuantity 
of  acid,  proportionate  to  the  quantity  of  madder,  is  allowed  to  run  down  through  the  per- 
forated bottom  and  mix  with  the  hot  li(]uor ;  the  acidulated  li(|uor  then  i-uns  into  the  vat,  a 
tightly  fitting  cover  on  which  keeps  the  liquor  hot.  When  the  day's  dyeing  is  done,  the  vat 
is  left  covered  up  all  night ;  next  day  the  lid  is  raised,  and,  by  means  of  holes  and  pegs  in 
the  side  of  the  vat,  all  the  clear  liquor  is  drained  away,  the  vat  filled  anew  with  water, 
stirred  up,  and,  when  settled,  the  clear  drawn  off'  again  ;  this  washing  being  repeated  till  all 
the  acid  is  washed  away,  the  garanceux  is  then  run  on  a  filter  to  drain  for  use.     The  advan- 


264 


CALICO  FEINTING. 


tages  of  this  plan  are,  first,  the  saving  of  fuel,  by  economizing  the  heat  of  the  waste  liquor, 
and,  secondly,  the  production  of  one-lourfli  more  coloring  matter. 

Tliird  Style :  Reserved. 

Maddered  or  garancined  goods  are  often  left  with  white  spots,  as  leaves,  &c.,  and  when 
dved  these  spaces  are  filled  with  various  bright  colors,  such  as  green,  blue,  yellow,  &c. 
These  colors  are  the  ordinary  steam  colors,  described  hereafter,  and  are  fixed  in  the  same 
manner. 

Another  way  of  combining  madder  or  garancin  colors  with  steam  colors,  is  by  blocking 
on  the  dyed  object,  generally  groups  of  flowers,  a  reserved  paste,  (No.  39,)  and  when  this  is 
dry,  covcritiff  by  machine  in  small  patterns  with  various  shades  of  drab,  olive,  &c.,  (Nos.  5, 
44,  46,  &c.,)  which  then  are  dunged  and  dyed  with  quercitron  bark,  cochineal,  madder,  and 
bark,  kc,  &c.  Where  the  paste  has  been  applied,  the  colors  underneath,  or  the  white  spots 
reserved,  are  unafl'ected  by  the  covering  color,  and  stand  out  clear  surrounded  by  the  cov- 
ering color.  In  the  white  spaces  reserved  are  now  blocked  steam  colors,  which  are  raised 
by  steam,  as  described  further  on. 

Fourth  Style :  Padded. 

In  this  style  the  white  cloth  is  mordanted  all  over  by  padding  in  red  or  iron  liquor,  or 
mixtures  of  them,  drying  in  the  padding  flue  ;  then  a  pattern  is  printed  on  in  acid,  and  the 
usual  dunging  and  dyeing  operations  performed,  the  result  being  a  dyed  ground  with  a 
white  pattern. 

Fiff.  137  represents  a  section  of  the  padding  flue  used  in  mordanting  to  this  style. 


It  consists  of  a  long  vaulted  chamber,  about  35  yards  long  by  5  yards,  and  4  yards  high, 
cut  in  two  at  nearly  half  its  length,  by  6  small  arches  built  in  an  opposite  direction  to  that 
of  the  chamber,  the  object  of  which  is  to  preserve  the  principal  arch  from  the  action  of  the 
heat,  and  to  hinder  the  dried  pieces  from  being  exposed,  on  coming  to  the  higher  part,  to 
moisture  and  acids,  which  are  disengaged  in  great  abundance,  and  might  condense  there, 
c  c  is  a  long  furnace,  the  flue  of  which  forms  the  bottom  of  the  chamber ;  the  top  of  the 
flue  is  covered  with  plates  of  cast-iron  fitting  one  into  another,  and  which  can  be  heated  to 
near  red  heat  by  the  flame  of  the  furnace,  f  is  an  arched  passage,  by  which  the  interior  of 
this  store  can  be  reached,  h  h  are  ventilating  holes  in  the  lateral  wall,  which  can  be  opened 
and  closed  at  will  by  means  of  the  rod  _;,  which  is  connected  with  sliding  doors  over  the 
apertures,  kk  are  oast-iron  supports  for  turned  copper  rollers,  which  are  fixed  to  the  cross 
pieces  y  y,  and  serve  to  conduct  the  piece.  1 1  are  bars  of  iron  which  carry  the  fans  rn  in, 
which  are  covered  by  gratings,  and  make  about  300  turns  per  minute. 

In  front  of  this  hot  flue  is  placed  all  the  apparatus  necessary  for  padding  the  pieces,  and 
moving  them  through  the  drying  chambers.  This  movement  is  caused  by  pulleys  n  n  driven 
from  a  prime  mover. 

The  mordant  liquor  being  put  in  the  box  of  the  padding  machine,  the  pieces  wound  on 
a  beam  and  placed  above  the  machine  are  conducted  through  the  box,  then  between  the  two 
lowest  rollers  above  the  box,  from  them  through  the  liquor  again,  passing  next  through  the 
highest  rollers,  and  so  into  the  flue,  their  course  being  easily  traced  by  the  arrows ;  on  leav- 
ing the  flue  dry,  they  are  wound  on  a  beam,  or  plated  down  on  the  wooden  platform  behind 
the  machine.  The  3  rollers  of  the  padding  machine  are  made  of  brass,  and  are  wrapped 
with  a  few  folds  of  calico  ;  the  iron  journals  of  them  work  in  slots,  the  lowest  one  being  at 


CALICO  PRINTING. 


265 


the  bottom  of  the  slot  working  in  brass  bearings ;  a  weighted  lever  presses  the  top  roller  iu 
forcible  contact  with  the  others. 

Padded  goods,  after  printing  in  acid,  are  hung  2  or  3  days  in  the  ageing  room,  dunged, 
and  dyed.     A  few  of  these  shades  are  here  given  : — 

a.  Caret  and  lohife. — Pad  in  red  liquor  at  10^  F.,  dry,  cool,  and  pad  again  in  same 
liquor,  dry,  cool,  and  print  in  acid  No.  37,  age  3  nights.  Fly  dung  at  boil,  wash,  second 
dung  at  IGO'  F.,  *  hour,  wash,  dry,  and  sinffc,  wash  and  dye  12  pieces  7  ft.  8  in.  30  yards 
with  18  lbs.  ground  peachwood,  21  lbs.  of  t>ench  madder,  6  lbs.  sumac,  5  lbs.  prepared  log- 
wood, run  the  pieces  in  the  beck  cold  for  20  minutes,  and  then  bring  to  a  boil  in  1  hour 
and  10  minutes,  boil  1.5  minutes,  get  out,  rinse  and  wash,  bran  10  minutes  at  boil  in  a  bock 
with  a  i'ew  pounds  of  bran,  rinse  in  a  pit  and  bran  again  at  boil,  wash  and  dry. 

Prepared  Logwood  is  thus  male. — Grountl  logwood  is  spread  out  on  a  floor,  damped 
with  water,  and  heaped  up.  It  is  then  turned  over  once  a  day  for  a  fortnight,  and  occa- 
sionally wetted,  during  which  time  it  changes  from  a  dull  red  to  a  bright  scarlet.  It  is  then 
ready  for  use.  Some  change,  probably  oxidation,  has  taken  place,  and  the  wood  dyes  fur- 
ther after  this  process. 

b.  Scarlet  and  white. — Padded  and  dunged  as  for  clarets  ;  then  10  pieces  dyed  with  15 
lbs.  French  madder,  15  lbs.  Dutch  crop  madder,  7  lbs.  peachwood,  4  lbs.  sumac,  with  3 
quarts  bone  size ;  bring  to  a  boil  in  2^  hours,  and  boil  a  quarter  of  an  hour ;  wash  and 
bran,  &c. 

c.  Scarlet  and  yellow. — Proceed  as  for  scarlet  and  white,  but  dye  10  pieces  with  22| 
lbs.  crop  Dutch  madder,  22}  lbs.  French  madder,  7^  lbs.  sumac,  wash,  bran,  and  dry;  then 
pad  in  red  liquor  at  10'  T.,  age  2  nights,  fly  dung  at  130"  F. ;  wash  and  warm  water  at 
120^  10  minutes,  dye  10  pieces  with  20  lbs.  quercitron  bark,  heat  to  120^  in  1  hour,  keep 
at  120'  15  minutes,  wash  and  dry. 

d.  Burgnndy  and  white. — Pad,  &c.,  as  for  clarets;  dye  10  pieces  with  18  11)S.  French 
madder,  18  lbs.  peachwood,  1^  lbs.  logwood,  5  lbs.  sumac,  4  quarts  glue.  Heat  to  boil  in 
If  hours,  boil  a  quarter  of  an  hour,  wash  and  bran  at  boil  10  minutes,  wash  and  dry. 

e.  Tyrian  purple  and  white. — Pad,  &c.,  as  for  clarets  ;  dye  10  pieces  with  5  lbs.  prepared 
logwood,  5  lbs.  Dutch  crop  madder,  and  7  lbs.  peachwood,  2  lbs.  bran,  and  3  quarts  bone 
size.  Bring  to  boil  in  1|  hours,  boil  a  quarter  of  an  hour,  wash  and  bran  at  150'  5  minutes 
with  1  lb.  bran  per  piece,  wash  and  dry. 

/.  Puce  and  white. — Pad,  &c.,  as  for  clarets;  dye  12  pieces  with  3  lbs.  fine  ground 
cochineal,  1  lb.  ground  galls,  4  lbs.  prepared  logwood,  3  lbs.  peachwood,  heat  to  170°  in  1 
hour  and  20  minutes,  keep  at  170^  10  minutes,  wash,  bran  at  160'  10  minutes;  wash  and 
dry. 

ff.  Amber  and  white. — Pad,  &c.,  as  for  clarets ;  dye  10  pieces  with  20  lbs.  quercitnm 
bark,  10  lbs.  Dutch  crop  madder,  2  quarts  bone  size.  Heat  to  160"  in  1  hour  and  15 
minutes,  keep  at  160'  15  minutes,  wash,  bran  10  minutes  at  150" ;  wash  and  dry. 

h.  Peach  and  white. — Pad,  &c.,  as  for  clarets ;  dye  10  pieces  with  2  lbs.  ground  cochi- 
neal, 2  lbs.  peachwood,  6  oz.  logwood,  heat  to  140'  in  1:^  hours,  wash,  bran  at  140'  10 
minutes ;  wash  and  dry. 

i.  Black  and  white. — Pad  in  red  liquor  at  20"  T.  once ;  print  in  No.  36,  ago  3  nights, 
fly  dung  at  boil,  second  dung  at  140'  20  minutes,  wash,  dry,  and  singe  ;  wash  and  dye  10 
pieces  with  60  lbs.  prepared  logwood,  4  gallons  of  bone  size,  and  6  oz.  carbonate  of  soda 
crystals,  heat  to  boil  in  1  hour  and  10  minutes  ;  wash  well  and  dry. 

k.  Olive,  drabs,  d'c.,  with  white. — A  great  variety  of  shades  may  be  obtained  by  varying 
the  mordants.  For  drabs,  pad  in  iron  liquor  diluted  about  10  times,  according  to  the  shade 
wanted,  and  dye  in  bark,  or  bark  and  logwood.  For  olives,  pad  in  mixtures  of  red  liquor 
and  iron  liquor,  diluted,  and  dye  in  bark,  or  bark  and  logwood.  The  acid  used  may  be 
No.  33. 

/.  Bark  dyeing. — Dye  10  pieces  with  25  lbs.  bark,  and  3  quarts  bone  size ;  heat  to  190" 
in  1|  hours,  and  keep  at  190"  10  minutes,  wash  and  bran  at  160°  10  minutes;  wash  and 
dry. 

m.  Bark  and  Logwood  dyeing. — Dye  10  pieces  with  20  lbs.  bark,  and  30  oz.  i)reparcd 
log\yood,  with  3  quarts  bone  size  ;  heat  as  in  bark  dyeing. 

Fifth  Style :  Indigo. 

The  indigo  dye-house  is  always  on  the  ground  floor  of  a  building,  and  is  fitted  up  with  a 
number  of  stone  vats  let  into  the  ground.  There  are  generally  several  rows  of  these  vats, 
about  3  feet  apart.  They  arc  about  8  feet  long  by  4  feet  wide,  and  8  to  10  feet  deep. 
Some  of  them  have  steam  pipes  inserted,  which  go  to  near  the  bottom,  so  that  they  can  be 
heated  when  necessary.     Th.'rc  are  about  10  vats  in  a  row. 

A.   Blue  and  white. — The  simplest  form  of  blue  styles  is  lihie  and   white  ;  dark  blue  * 
ground  with  white  figures.     The  cloth  is  ])rinted  in  one  of  the  following  reserve  pastes  : — 

No  65.  lienerve  paste  for  Block. — 3  lbs.  sulphate  of  copper,  dissolved  in  1  gallon  of 
water,  15  lbs  pipe-clay,  heat  up  with  some  of  the  licpior  ;  1  gallon  of  thick  gum  Senegal  so- 
lution, and  1  (}uart  of  nitrate  of  copper  at  80"  T. 


266 


CALICO  FEINTING. 


No.  66.  Reserve  paste  for  Machine. — ih  lbs.  sulphate  of  copper,  1  gallon  of  water, 
thickened  with  9  lbs.  flour,  and  2  lbs.  dark  British  gum. 

No.  (u.  Reserve  paste  for  Machine. — 5  lbs.  sulphate  of  copper,  2  lbs.  white  acetate  of 
lead,  2  gallons  water,  dissolve  and  thicken  the  clear  with  3  lbs.  flour  and  2  lbs.  pale  British 
gum';  when  cold,  add  half  a  pint  of  nitrate  of  copper  at  80°  T.,  to  every  2  gallons  of  color. 

No.  08.  Reserve  paste  for  Machine. — 4  gallons  boiling  water,  IG  lbs.  of  sulphate  of 
copper,  8  lbs.  white  acetate  of  lead,  let  settle  and  pour  oft"  the  clear  liquor ;  thicken  3  gal- 
lons of  this  with  8  lbs.  of  flour,  and  4  lbs.  pale» British  gum.  When  boiled,  add  4  lbs.  sul- 
phate of  zinc,  and  dissolve.  The  foregoing  are  all  to  resist  deep  shades  of  blue,  for  light 
shades  of  blue  dipping  any  of  the  following  : — 

No.  09.  Mild  paste  for  Block. — 25  lbs.  dark  British  gum,  15  quarts  of  water,  boil  10 
minutes,  and  add  74  lbs.  soft  soap  ;  stir  well  in,  and,  when  mixed,  add  20  lbs.  sulphate  of 
zinc,  stir  well  in,  and  add  10  lbs.  pipe-clay,  beaten  up  into  Vi  quarts  of  water,  and  7^  gills 
of  nitrate  of  copper  at  SO'  T.     Mix  all  well  together. 

No.  70.  Mild  paste  for  Machine. — 8  lbs.  dark  British  gum  ;  3f  quarts  water  ;  boil  and 
add  2  lbs.  soft  soap,  cool,  and  add  G  lbs.  sulphate  of  zinc  dissolved  in  2  quarts  of  boiling 
water  and  1  quart  of  nitrate  of  copper  at  80°  T. 

After  printing  in  one  of  these  reserves,  hang  in  a  rather  humid  atmosphere  for  2  days, 
and  then  dip  blue. 

Iiuligo  for  use  in  the  dye-house  is  ground  with  water  to  a  fine  pulp  ;  a  series  of  cast-iron 
mills  with  curved  bottoms,  are  arranged  in  a  line :  one  or  two  iron  rollers  are  moved  back- 
wards and  forwards  on  the  curved  bottom  in  each  mill  by  an  upright  rod,  which  is  furnished 
with  a  roller  at  the  bottom,  and  is  connected  with  a  horizontal  rod  worked  by  an  eccentric. 
Indigo  and  a  certain  quantity  of  water  are  left  in  these  mills  several  days,  till  the  pulp  is 
perfectly  smooth.     The  method  of  blue  dipping  is  as  follows  : — 

In  a" line  of  ten  vats,  the  first  one  is  set  with  lime  ;  as — 

(No.  1.)  1,000  gallons  water,  250  lbs.  of  hydrate  of  lime,  or  lime  slaked  to  a  dry  pow- 
der ;  when  used,  it  is  well  raked  up. 

The  indigo  vats  vary  according  to  the  style  of  work  ;  for  deep  blue  and  white,  or  blue 
and  yellow,  or  orange,  the  following  is  a  good  one  : — 

(No.  2.)  1,000  gallons  water,  50  lbs.  indigo  previously  pulped,  140  lbs.  copperas,  and 
170  lbs.  lime;  dissolve  the  copperas  in  the  water,  then  add  the  indigo,  stir  well  up,  and 
add  the  lime,  previously  riddled  to  separate  small  stones.  Rake  up  every  two  hours  lor  two 
davs,  and  let  settle  clear.  The  clear  liquor,  when  taken  up  in  a  glass,  must  have  a  deep 
veilow  color,  be  perfectly  transparent,  and  be  immediately  covered  with  a  pellicle  of  regen- 
erated indigo  when  exposed  to  the  air.     Eight  or  nine  vats  are  all  set  alike. 

The  pieces  to  be  dipped  are  hooked  backwards  and  forwards  on  a  rectangular  frame 
which  just  fits  the  vats,  so  that  the  cloth  can  be  immersed,  but  still  not  so  deep  as  to  touch 
the  sediment  of  the  vats.  The  process  is  thus  performed : — The  lime  vat  No.  1  being 
stirred  up,  the  frame  which  contains  two  pieces,  is  lowered  down  into  it,  so  as  to  completely 
immerse  the  pieces ;  a  gentle  up  and  down  movement  is  given  by  hand.  The  frame  is 
allowed  to  stay  10  minutes  in,  is  then  lifted  out,  and  supported  over  the  vat  by  rods  put 
across.  After  draining  here  a  few  minutes,  it  is  then  removed  and  immersed  in  vat  No.  2, 
or  the  first  indigo  vat.  It  stays  here  seven  minutes,  is  lifted  out,  apd  drained  as  before  over 
the  vat  8  minutes,  then  removed  to  No.  3  vat,  and  so  on,  till  it-has  gone  through  the  whole 
series,  or  till  the  shade  of  blue  is  considered  strong  enough.  After  the  last  dip,  the  pieces 
are  unhooked  and  winced  in  a  pit  of  water,  then  winced  about  10  minutes  in  a  pit  contain- 
ing sulphuric  acid  at  6'  T.,  washed  well  in  the  wheel,  squeezed,  and  dried.  In  large  dye- 
houses,  there  is  an  arrangi-mcnt  for  collecting  all  the  waste  indigo  which  is  washed  off  the 
pieces,  by  running  all  the  water  used  into  a  vaulted  chamber  under  the  dye-house,  where  it 
passes  from  one  compartment  to  another,  gradually  depositing  the  suspended  indigo,  which 
is  periodically  removed. 

In  heavy  bodies  of  color,  the  paste  sometimes  slips,  or  the  shapes  become  irregular ;  this 
is  counteracted  by  using  the  first  indigo  vat  raked  up  instead  of  clear.  The  vats  are  used 
till  nearly  exhausted,  and  then  the  clear  liquor  pumped  off",  to  be  used  instead  of  water  for 
setting  fre.sh  vats  with. 

n.  Blue  and  Yellow,  or  Orange. — Print  in  one  of  the  reserve  pastes,  and  yellow  or 
orange  color  made  as  follows  : — 

No.  71.  Chrome  yclloiv  for  Machine. — 2  gallons  water,  20  lbs.  sulphate  copper,  20  lbs. 
nitrate  of  lead ;  dissolve,  and  beat  up  with  12  lbs.  flour,  and  2  gallons  sulphate  of  lead  bot- 
toms ;  boil  all  together. 

The  sulphate  of  lead  here  is  the  by-product  in  making  red  mordant  No.  8,  and  is  drained 
to  a  thick  paste. 

No.  72.  Orange. — Make  a  standard  liquor  by  dissolving  24  lbs.  white  acetate  of  lead  in 
6  gallons  water,  and  stirring  12  lbs.  litharge  in  it  till  perfectly  white,  then  let  settle,  and 
use  the  clear. 

For  the  orange  color  take  two  gallons  of  this  standard  liquor,  instead  of  the  gallons  of 
water  in  the  above  veilow  color. 


CALICO  FEINTING.  207 

Follow  the  same  routine  in  dipping,  &c.,  as  for  blue  and  white.  After  wincing  in  sul- 
phuric acid  sours,  wash  well,  and  wince  10  minutes  in  bichromate  of  potash  solution,  2  oz. 
per  gallon  at  lUO'  V.  Wash  well,  and  wince  in  dilute  muriatic  acid  at  V  T.  containing  1 
oz.  oxalic  acid  per  gallon,  till  the  }-ellow  is  quite  bright.  The  small  quantity  of  chromic 
acid  set  free  oxidizes  and  destroj^s  the  indigo  that  may  be  attached  to  the  yellow  color. 
After  this  souring,  wash  and  dry. 

If  orange  was  printed  instead  of  yellow,  treat  as  for  yellow  ;  and  after  the  murio-oxalic 
sour,  wash,  and  raise  orange  in  the  following : — 10  lbs.  bichromate  of  potash,  300  gallons 
water,  and  sufficient  slaked  lime  to  make  slightly  milky ;  heat  to  180"  F.,  and  wince  the 
pieces  in  till  the  orange  is  full  and  bright ;  then  take  out,  and  wash  well,  and  dry. 

Other  varieties  of  blue  dyeing  are  : — 

c.  Two  blues. 

D.  Two  blues  and  white. 

E.  Two  blues,  white,  and  yellow  or  orange. 

F.  Dark  blue  and  green. 

G.  Two  blues  and  yellow. 

For  c  and  k  a  pale  shade  of  blue  is  first  given  the  cloth.  The  light  blue  vat  is  thus 
composed : — 

(Xo.  3.)  Liffht  Blue  Vat. — 1,000  gallons  water,  40  lbs.  indigo,  10  lbs.  copperas,  80  lbs. 
lime.  For  c.  Dip  light  blue  by  three  immersioiis,  drawing  well  between ;  unhook,  wince 
in  water,  then  in  sulphuric  sours  at  2"  T.  ;  wash,  squeeze,  and  dry  ;  then  print  on  a  reserve 
paste,  and  proceed  as  for  dark  blue  and  white ;  when  finished,  the  pale  blue  having  been 
protected  by  the  reserve,  has  remained  unaltered,  all  the  rest  being  dark  blue. 

For  F.  Instead  of  reserve  paste,  print  on  yellow  No.  71,  and  dip  dark  blue,  sour  and 
raise  the  yellow  with  bichromate  of  potash,  omit  the  souring  after  chroming,  and  wash  and 
dry.     The  yellow  falling  on  the  pale  blue,  makes  a  green. 

For  D.  On  white  cloth  print  a  nobject  in  muriate  of  manganese,  thickened  with  dark 
British  gum,  raise  this  as  described  under  the  head  Bronzes,  dry  and  block  in  a  reserve 
paste  Xo.  65,  then  lime  and  dip  in  the  dark  blue  vat,  letting  stay  in  half  an  hour,  remove, 
oxidize  in  the  air,  wash  and  sour  with  dilute  muriatic  acid,  to  which  some  muriate  of  tin 
liquor  has  been  added,  wash  and  dry  ;  where  the  peroxide  of  manganese  has  been  is  now 
dark  blue,  the  ground  pale  blue  with  white  object. 

For  K.  Print  as  d,  with  yellow  or  orange  in  addition,  and  after  the  sulphuric  sours,  raise 
yellow  or  orange  as  before. 

Dip  light  blue,  print  reserve  paste  and  yellow,  dip  dark  blue,  wince,  sour  in  sulphuric 
sours  at  6'  T.,  wince  in  water,  chrome  at  140°  F.  10  minutes  at  2  oz.  bichromate  per  gallon, 
wince,  wash,  and  sour  in  the  following : — 7  lbs.  oxalic  acid,  3  lbs.  strong  sulphuric  acid ; 
dilute  with  water  to  standard  8°  T. ;  wince  till  the  yellow  is  bright,  then  wash  and  dry. 

A  style  formerly  very  much  in  vogue,  but  now  scarcely  ever  used,  is  the  neutral  or  Laz- 
ulite  style.  It  consists  in  combining  mordants  with  reserves,  and  dipping  blue  ;  the  colors 
throw  off  the  blue,  and  are  subsequently  dyed  with  madder. 

Xeutrals  are  of  two  sorts  : 

1.  Where  reds  and  chocolate,  or  black,  with  resist  white  are  printed,  and  dipped  light 
blue,  the  resist  white  being  only  required  to  resist  the  blue. 

2.  Where  the  white  is  required  to  cut  through  the  block,  reds  or  chocolate  in  addition 
to  the  blue. 

The  following  are  examples  of  lazulite  colors  for  the  first  variety  : 

Xo.  73.  Black,  {Machine.) — 4  quarts  logwood  liquor  at  12"  T.,  1  quart  gall  liquor  at  9' 
T.,  1  quart  red  liquor  at  20'  T.,  1  quart  iron  liquor  at  24'  T.,  1  quart  acetic  acid,  thicken 
with  3  lbs.  flour,  and  8  oz.  starch ;  when  boiled,  add  1  pint  Gallipoli  oil,  and  1  pint  tur- 
pentine. 

X^o.  74.  Chocolate,  {Machine.) — 5  quarts  red  liquor  at  12^  T.,  1  quart  iron  liquor  at  24° 
T.,  1|  lbs.  sulphate  of  copper,  24  oz.  measure  of  nitrate  of  copper  at  100°  T.,  thicken  with 
2\  lbs.  flour,  and  h  lb.  dark  British  gum. 

No.  75.  Chocolate,  {Block.) — 5  quarts  red  liquor  12°  T.,  1  quart  iron  liquor  24°  T.,  2^ 
lbs.  sulphate  of  copper,  36  oz.  measure  nitrate  of  copper  at  100°  T.,  9  lbs.  pipe-day  beat  up 
well,  and  add  3  quarts  of  gum  Senegal  solution  at  5  lbs.  per  gallon. 

Xo.  76.  Dark  Resist  Red,  {Block.) — 2  quarts  red  liquor  22°  T.,  5Joz.  white  acetate  of 
lead,  4^^  oz.  sulphate  of  copper,  dissolve,  and  beat  up  in  it  6|  lbs.  piiie-clay.  Thicken  sepa- 
rately 2  quarts  red  lic[Uor  at  12°  T.,  with  12  oz.  flour,  and  add,  when  boiling  hot,' 8  oz.  of 
soft  soap  melted  ;  mix  well,  add  tiie  pipe-clay  mixture  to  this,  and  then  2  (juarts  red  liquor 
at  2°  T.,  thickened  by  dissolving  gum  Senegal  in  it.     Stir  the  whole  well  together. 

Xo.  77.  Dark  resist  Red,  {Machi7ie.) — 20  quarts  nitrate  of  zinc  at  36  B.,  10  (juarts  water 
colored  with  a  little  peachwood,  12i  lbs.  alum,  10  li)s.  acetate  of  lead  ;  dissolve  all  together 
with  heat,  stir  till  cool,  thicken  all  together  with  8  ll)s.  fl<)\n',  and  li  lbs.  dark  British  gum. 

No.  78.  Any  shade  of  pale  red  is  made  for  block  by  substituting  the  red  liquor  in  color 
No.  76  by  the  mordant  Xo.  8  reduced  with  water,  according  to  the  shade  wanted. 


2G8  CALICO  PKINTING. 

No.  79.  Any  shade  of  pale  red  for  machine  is  made  by  reducing  the  quantities  of  alum 
and  acetate  of  lead  in  color  No.  77. 

The  white  reserve  for  this  variety  of  neutrals  is  either  of  the  mild  pastes. 

No.  80.  liesist  Brown. —  2  gallons  water,  24  lbs.  catechu,  6  lbs.  sal  ammoniac,  1  gallon 
acetic  acid  ;  boil  15  miuutes,  and  add  7.7  gallons  gum  solution,  5  quarts  nitrate  of  copper  at 
lUU^  T. 

Proccxx. — The  colors  after  printing  are  aged  3  days,  then  dipped  light  blue  in  the  fol- 
lowing blue  vat. 

(No.  4.)  Neutral  vat. — 1,000  gallons  water,  120  lbs.  indigo,  135  lbs.  copperas,  150  lbs. 
lime  ;  rake  up  for  two  days,  and  let  .settle. 

A  I'ranie  with  rollers  toj)  and  bottom  is  lowered  into  this,  and  the  pieces  are  run 
through  ;  after  leaving  the  vat,  they  are  made  to  travel  over  rollers  in  the  air  for  a  sufficient 
distance  to  turn  them  blue  ;  then  into  a  pit  of  water,  from  that  into  a  beck  with  cow  dung 
and  water,  at  160"  l'\,  where  they  run  15  minutes,  then  washed  and  dyed  madder  or  garan- 
cin,  &c.  &c. 

In  the  second  variety  of  neutrals,  the  white  is  required  to  resist  both  mordants  and  blue, 
and  is  made  thus  : — 

No.  81.  Neutral  White  for  Blocks. — 7  quarts  lime  juice  at  30°  T.,  1  quart  water,  4^  lbs. 
suljiliate  of  copper,  24  lbs.  pipe-clay,  3^  quarts  lime  juice  at  30°  T.,  previously  thickened 
with  gum  Senegal.  ' 

No.  82.  Neutral  WIdte  for  Mncfiine. — 1  gallon  lime  juice  at  42°  T.,  2  lbs.  sulphate  of 
copper,  32  oz.  measure  nitrate  of  copper  at  100"  T.,  thickened  with  1^  lbs.  starch. 

The  black  is  the  ordinary  madder  or  garancin  black,  Nos.  4  and  5  process. 

The  neutral  white  is  first  printed  either  by  block  or  machine  ;  if  the  latter,  it  cannot  be 
in  a  pattern  which  should  register  accurately  with  the  subsequent  colors,  as  it  must  be  dried 
perfectly  before  the  other  colors  are  printed,  to  avoid  obtaining  irregular  shapes  ;  the  above 
reserve  colors  are  then  printed  over  the  neutral  white.  Mild  paste  Nos.  71,  72  may  also  be 
printed  along  with  the  other  colors,  to  reserve  a  white  under  the  blue  only.  The  subsequent 
process  is  the  same  as  for  the  first  variety. 

After  dyeing  madder  and  garancin,  and  clearing  with  soap,  &c.,  steam  or  spirit  colors 
arc  generally  blocked  in.     Parts  of  the  yellow  being  made  to  fall  over  the  blue  form  gi-een. 

Sixth  S'ylc  :   China  Blues. 

China  bines,  so  called  from  the  shade  of  blue  resembling  that  on  porcelain.  In  this 
style  indigo  is  printed  on,  and  made  to  penetrate  and  fix  in  the  cloth  by  the  subsequent 
process. 

The  color  is  made  thus : — 

No.  83.  Standard  China  Blue. — In  an  indigo  mill  are  put  45  lbs.  indigo,  9  gallons  iron 
liquor  at  24°  T.,  and  IS  lbs.  copperas,  the  whole  ground  till  quite  fine  ;  then  add  7i  gallons 
gum  Senegal  solution  at  6  lbs.  per  gallon  ;  grind  an  hour  longer,  take  out  and  wash  the  mill 
with  6  quarts  hot  water,  and  add  to  the  above. 

No.  84.  China  blue  f/iwi. — Gum  Senegal  solution  at  3  lbs.  per  gallon,  containing  4  oz. 
copperas  per  gallon. 

Colors  are  made  by  reducing  the  standard  blue  with  the  gum,  according  to  the  pattern 
and  strength  required.     Vov  instance,  for  two  blues  of  medium  shades  : — 

No.  85.  Strouff  Blue. — 1  volume  standard,  2  volumes  gum. 

No.  80.  J'ale  Bine. — 1  volume  standard,  10  volumes  gum. 

After  printing,  age  one  night,  and  raise  as  follows : — Two  vats  similar  to  indigo  vats  arc 
set.  No.  1.  1,000  gallons  water,  500  lbs.  slaked  and  dry  lime. — No.  2.  Solution  of  cop- 
peras at  5°  T.  In  each  vat  is  lowered  a  frame,  which  is  provided  with  rollers  at  top  and 
bottom,  and  in  addition  has  a  pair  of  bushes  at  each  side  of  the  frame,  just  above  the  surface 
of  the  liquor,  in  which  are  jiut  beams,  on  which  the  pieces  are  wound  alternately ;  the  bear- 
ings of  the  beams  l)eing  just  above  the  surfjicc  of  the  liquor,  allows  the  roll  of  pieces  to  be 
always  half  in  and  half  out  of  the  liquor.  -  The  course  of  proceeding  is  this  : — A  beam  con- 
taining two  or  three  pieces  stitched  end  to  end  is  placed  on  a  small  frame  at  one  side  of  vat 
No.  1,  and  by  means  of  a  cord  previously  threaded  through  the  rollers  in  the  vat,  the  pieces 
arc  slowly  wound  througli  the  vat  and  on  to  a  beam  placed  in  the  bearings  at  the  opposite 
side  of  the  vat,  by  means  of  a  winch  handle  fitted  on  this  beam  ;  when  the  pieces  have  thus 
passed  through  vat  No.  1,  which  is  kept  in  a  milky  state  all  the  time,  the  beam  is  lifted  out 
imd  transferred  to  one  of  the  pair  of  bearings  in  vat  No.  2  ;  the  pieces  are  wound  through 
this  vat- in  the  same  manner;  after  this  vat,  they  are  removed  to  No.  1  vat,  and  worked 
through  ;  this  alternate  liming  and  copi)crasing  is  continued  till  the  pieces  have  Ik  en  4  times 
through  each  vat;  tluMi  detach  and  wince  in  water ;  then  ])Ut  into  sulj)huric  sours  at  10' 
T.,  immersing  completely  in  the  liiiuor  till  the  whites  appear  (juite  clear ;  then  wa.sli  well, 
soap  in  a  beck  at  120'  F.  a  quarter  of  an  hour  with  a  ^  lb.  soap  per  piece  ;  wash  again  and 
sour  in  sulphuric  sours  at  1°  T.  at  11<>'  F.  ;  wash  well  and  dry. 

The  various  phenomena  which  occur  in  tlie  dipping  of  China  blues  are  not  difficult  of 


CALICO  FEINTING. 


269 


explanation  with  the  lights  of  modern  chemistry.  We  have,  on  the  one  hand,  indigo  and 
sulphate  of  iron  alternately  applied  to  the  clotli ;  by  dipping  it  into  the  lime,  the  blue  is  de- 
oxidized, because  a  film  of  the  sulphate  of  iron  is  decomposed,  and  protoxide  of  iron  comes 
forth  to  seize  the  oxygen  of  the  indigo,  to  make  it  yellow-green,  and  soluble  at  the  same 
time  in  lime  water.  Then,  it  penetrates  into  the  heart  of  the  fibres,  and,  on  exposure  to  air, 
absorbs  oxygen,  so  as  to  become  insoluble,  and  fixed  within  their  pores.  On  dipping  the 
calico  into  tlie  second  vat  of  sulphate  of  iron,  a  layer  of  oxide  is  formed  upon  its  whole  sur- 
face, which  oxide  exercises  an  action  only  upon  those  parts  that  are  covered  with  indigo, 
and  deoxidizes  a  portion  of  it ;  thus  rendering  a  second  dose  soluble  by  the  intervention  of 
the  second  dip  in  the  lime  bath.  Hence  we  see  that  while  these  alternate  transitions  go  on, 
the  same  series  of  deoxidizement,  solution,  and  re-oxidizement  recurs ;  causing  a  progres- 
sively increasing  fixation  of  indigo  within  the  fibres  of  the  cotton. 

Other  indigo  stylos  are  dipped  greens,  blue  with  white  discharge. 

Dipped  Greens. — There  are  4  vats  similar  to  indigo  vats  in  a  row,  set  with  : — 

First:  (No.  5.)  Light  blue  Vats  for  Greens. — 1,000  gallons  water,  25  lbs.  indigo,  45 
lbs.  copperas,  65  lbs.  lime,  dry  slaked,  lY  lbs.  caustic  soda,  24"  T.  ;  raked  up  2  days,  and 
settled  clear. 

Second  :  (No.  6.)  Yellow  Vat  for  ■Grec7is.— 1,000  gallons  water,  250  lbs.  brown  acetate 
of  lead,  130  lbs.  dry  slaked  lime  ;  rake  up  tUl  dissolved,  and  let  settle  clear. 

Third  :  (No.  7.)  Filled  with  water  only. 

Fourth  :  (No.  8.)     Set  with  bichromate  of  potash  at  4°  T. 

Each  of  these  vats  is  mounted  with  a  frame  with  rollers  top  and  bottom ;  the  pieces  to 
be  dipped  are  stretched  end  to  end,  and  a  length  of  cord  being  threaded  through  all  the 
vats  and  fastened  to  a  drawing  roller  at  the  end  of  the  fourth,  the  pieces  are  drawn  slowly 
thorough  between  the  first  and  second  ;  the  cloth  is  made  to  travel  several  yards,  so  as  to 
injure  oxidation  of  the  indigo  before  going  into  the  lead  vat ;  after  leaving  the  fourth,  they 
are  detached,  winced,  and  washed  well. 

For  dipped  greens,  either  white  cloth  is  printed  in  patterns,  as  spots,  &c.,  with  mild 
paste,  Nos.  69,  70 ;  or  a  pattern  previously  printed  in  madder  colors  and  dyed,  &c.  is  covered 
up  with  mild  paste  by  block ;  the  cloth  being  now  dipped  green,  the  pattern  or  spots  are  re- 
served or  untouched  by  the  green  :  a  very  good  effect  is  produced  by  dipping  the  Burgundy 
and  acid  No.  4,  green,  when  the  Burgundy  part  comes  out  a  beautiful  chocolate,  and  the 
white  part  green. 

Acid  Discharge  on  Bine. — A  blue  and  white  style,  but  which  permits  the  most  delicate 
pattern  to  be  printed,  which  is  not  the  case  with  the  ordinary  blue  and  white  style.  The 
cloth  is  first  dipped  a  medium  shade  of  blue,  washed  and  dried,  then  padded  in  bichromate 
of  potash  at  6'  T.,  and  carefully  dried  in  the  shade,  without  artificial  heat,  and  printed  in 
the  following  color  : — 

No.  87.  White  Discharge  for  Blues. — 1  gallon  water,  thicken  with  2  lbs.  flour,  and  2 
lbs.  dark  British  gum  ;  when  partly  cooled,'  add  2  lbs.  oxalic  acid,  and  when  quite  cold,  1\ 
oz.  measure  sulphuric  acid.  A  few  seconds  after  the  color  is  printed  on  the  padded  cloth 
the  blue  is  discharged,  and  a  dirty  white  left  in  the  printed  parts ;  after  printing,  the  pieces 
are  dried,  so  as  to  leave  them  slightly  damp,  and  immediately  winced  in  chalk  and  water, 
then  winced  in  sulphuric  sours  at  2"  T.,  winced  and  well  washed  ;  the  printed  pattern  is 
now  a  pure  white,  and  if  care  has  been  taken  not  to  dry  the  bichromate  too  hard,  and  not 
expose  it  to  sunlight,  the  blue  is  bright  and  good. 

This  ingenious  process  was  the  invention  of  Mr.  John  Mercer.  At  the  moment  the  block 
applies  the  preceding  discharge  to  the  bichromate  dye,  there  is  a  sudden  decoloration,  and  a 
production  of  a  peculiar  odor. 

The  pieces  padded  with  the  bichromate  must  be  dried  at  a  moderate  temperature,  and  in 
the  shade.  Whenever  watery  solutions  of  chromate  of  potash  and  tartaric  acid  are  mixed, 
an  effervescence  takes  place,  during  which  the  mixture  possesses  the  power  of  destroying 
vegetable  colors.     This  property  lasts  no  longer  than  the  effervescence. 

Seventh  Style :  Discharge  on  Turkey  lied  Ground. 

No.  88.  White  Discharge,  {Machine.) — 8  lbs.  light  British  gum,  1  gallon  tartaric  acid 
liquor  62'  T.,  1  gallon  acetic  acid  6'  T. 

No.  89.    White  Discharge,  [Block.) — The  above  color  a  little  thinner. 

No.  90.  Black  for  Turkey  Red.—I  gallons  logwood  liquor  at  8°  T.,  1  gallon  i)yr()ligno- 
ous  acid,  10  lbs.  starch  ;  boil  and  add  2  lbs.  10  oz.  copperas ;  boil  again  and  cool,  then  add 
3,V  pints  pernitrate  of  iron  at  80'  T.,  and  1  gallon  of  blue  paste. 

No.  91.  Blue  Paste. — (a)  6  lbs.  copperas,  2  quarts  water;  dissolve.  {!>)  4  lbs.  prussiate 
of  potash,  1  gallon  of  water ;  dissolve.  Mix  a  and  b  together,  and  add  1  quart  standard 
red  liquor  No.  8,  1  quart  nitric  acid  60'  T. 

No.  92.  Yelloio  Discharge,  (Block.)— \  gallon  lime  juice  at  50'  T.,  4  lbs.  tartaric  acid,  4 
lbs.  nitrate  of  lead ;  dissolve,  thicken  with  6  lbs.  pipe-clay,  and  3  lbs.  gum  Senegal. 

No.  93.  Yellow  Discharge,  {Machine.) — Thicken  the  above  with  l4  lbs.  starch,  instead 
of  the  pipe-clay  and  gum. 


270 


CALICO  PRINTING. 


No.  94.  Yellow  Discharge,  {Macldiic.) — 1  gallon  lime  juice  at  40°  T.,  4J-  lbs.  tartaric 
acid  5  lbs.  white  acetate  of  lead,  1 J  lbs.  starch ;  boil  and  cool,  then  add  1  lb.  14  oz.  nitric 
acid,  at  60°. 

No.  95.  Blue  Discharge,  {Machine.) — (a)  1  lb.  Prussian  blue,  1  lb.  oxalic  acid,  1  quart 
hot  water  ;  grind  well  together,  and  leave  to  react  on  each  other  24  hours ;  then  (6)  3 
quarts  of  water,  1^  lbs.  starch ;  boil,  and  add  2  lbs.  tartaric  acid,  and  mix  a  and  b  together. 
No.  96.  Green  Discharge,  {Machine.) — U  gallons  No.  95  blue,  1  gallon  No.  94  yellow. 
Process: — Print  in  any  of  the  above  colors,  and  as  soon  as  dry  from  the  machine,  put 
through  the  decoloring  vat. 

(No.  9.)  Decoloring  Vat. — 1,000  gallons  water,  1,000  lbs.  chloride  of  lime;  rake  well 
up,  till  quite  smooth  and  free  from  lumps,  then  immerse  a  frame  with  rollers  top  and  bot- 
tom as  in  dipping  greens,  &c. ;  keep  the  vat  stirred  up  so  as  to  be  milky,  and  run  the  pieces 
through  at  the  rate  of  1  piece  of  28  yards  in  3  minutes  ;  on  leaving  the  squeezing  rollers, 
conduct  into  water  and  rince,  then  wince  10  minutes  in  bichromate  of  potash  at  4°  T. ;  wash 
and  wince  in  very  dilute  muriatic  acid  ;  wash  well  and  dry. 

In  this  style,  such  is  the  permanence  of  the  Turkey  red  dye,  that  it  is  not  much  altered 
bv  passing  through  chloride  of  lime,  whilst  in  the  parts  printed  in  the  discharge  colors,  an 
instantaneous  disengagement  of  chlorine  takes  place,  which  decoJorizes  the  dyed  ground, 
and  where  a  mineral  color  or  mordant  formed  part  of  the  discharge,  it  is  left  in  place  of  the 
red  dye.  This  style  was  invented  in  1811  by  M.  D.  Ka?chlin,  and  patented  in  England  by 
Mr.  James  Thompson,  of  Primrose,  who  printed  immense  quantities  of  it. 

The  Bandanna  printing,  being  a  business  of  itself,  is  more  fitly  described  in  another 
place.     (See  Bandanna.) 

Eighth  Style  :  Steajn  Colors. 
The  printing  of  steam  celors  may  be  considered  as  a  mode  of  dyeing  at  one  operation, 
for  in  most  cases  one  or  more  mordants  are  mixed  with  dye-wood  decoctions,  and  printed 
on  the  cloth,  the  subsequent  steaming  causing  the  mordant  to  combine  with  the  coloring 
matter,  and  both  with  the  cloth.  Steam  colors,  in  some  cases,  are  made  so  as  to  produce  a 
fair  color  when  printed  on  ordinary  white  calico  ;  but  much  superior  colors  are  produced  by 
mordanting  the  cloth  first,  so  as  to  fix  peroxide  of  tin  in  the  fibre ;  and  as  this  is  the  almost 
universal  rule,  it  is  this  sort  of  steam  printing  alone  that  will  be  described.  Woollen 
fabrics,  indeed,  require  a  good  preparation  by  tin,  &e.,  before  lively  and  substantial  colors 
can  be  fixed  on  them  by  steam. 

The  following  is  the  mode  of  preparing  calicoes  for  steam  colors  : — 
Pad  the  pieces  stitched  together,  in  a  padding  machine  with  wooden  bowls,  through  a 
solution  of  stannate  of  .soda  at  10"  T,  twice  over,  letting  them  lie  wet  an  hour  between  ; 
immediately  after  padding  the  second  time,  run  through  a  cistern  with  rollers,  containing 
dilute  sulphuric  acid  at  H"  to  3"  T.,  thence  into  a  pit  of  water,  wince  well,  and  run  through 
a  washing  machine.  It  has  been  observed  by  Mr.  James  Chadwick,  that  if  the  cloth,  with 
oxide  of  tin  newly  precipitated  on  it,  is  subjected  to  any  severe  washing,  it  loses  a  consider- 
able quantity  of  oxide,  so  that  no  moro  washing  must  be  given  at  this  stage  than  will  remove 
the  free  sulphuric  acid.  It  appears  that  the  cloth,  once  dried  with  the  oxide  in  it,  does  not 
part  with  the  oxide  again  by  severe  washing.  After  washing,  the  pieces  are  unstitched,  and 
put  in  the  hydro-extractor,  then  dried  gently  over  the  steam  cylinders,  and  are  then  ready 
for  printing. 

The  following  list  of  steam  colors  comprises  the  usual  variety  of  shades  printed  on 
calico : — 

No.  97.  Steam  Black,  {3Iachine.) — 1  gallon  logwood  liquor  at  12°  T.,  1  quart  gall  liquor 
at  9'  T.,  •!  quart  mordant,  2  lbs.  flour,  6  oz.  starch  ;  boil  10  minutes,  and  add  ^  pint  nitrate 
of  iron. 

Steam  Black  Mordant. — 1  quart  acetic  acid,  1^  quarts  acetate  of  copper  at  3°  T.,  1^ 
quarts  iron  liquor  at  24°  T.,  1  quart  red  liquor  at  20°  T. 

No.  98.  Chocolate,  {Machine.) — 3  gallons  logwood  liquor  at  12°  T.,  2  gallons  Sapan 
li(|uor  at  12°  T.,  1  gallon  nitrate  of  alumina,  -J-  gallon  bark  liquor  at  12°  T.,  4  gallons  water, 
17  lbs.  starch;  boil,  and  add  8  oz.  chlorate  of  potash,  21  lbs.  red  prussiate. 

No.  99.  Dark  Blue,  {Machine.) — 7  gallons  water,  14  lbs.  starch,  2f  lbs.  sal  ammoniac; 
lioil,  and  add  whilst  hot  12  lbs.  yellow  prussiate  of  potash  in  powder,  6  lbs.  red  prussiate 
of  potash,  6  lbs.  tartaric  acid,  and  when  nearly  cold,  1  lb.  sulphuric  acid,  (specific  gravity 
1-85,)  1  lb.  oxalic  acid  dissolved  in  2  quarts  hot  water,  and  6  gallons  prussiate  of  tin  pulp. 

No.  100.  Dark  Blue. — 8  quarts  water,  4  lbs.  yellow  prussiate  of  potash,  3  lbs.  pale 
British  gum  ;  boil,  and  add  1  lb.  bisulphate  of  potash,  2  lbs.  muriate  of  ammonia,  8  oz. 
alum,  4  oz.  oxalic  acid,  4  oz.  sulphuric  acid  at  170  '  T.,  4  quarts  tin  pulp  No.  103. 

No.  101.  Cinnamon. — 1  quart  cochineal  liquor  at  8"  T.,  1  quart  logwood  liquor  at  8° 
T.,  1  quart  lierry  liquor  at  10"  T.,  6  oz.  alum,  4  oz.  cream  of  tartar,  8  oz.  starch  ;  boil,  and 
whilst  warm  add  3  oz.  muriate-of-tin  crj'stals. 

No.  li»2.   Orange. — 12  lbs.  annatto,  1  gallon  caustic  soda  at  70°  T.,  5  gallons  water ; 


I 


CALICO  PRINTING.  271 

boil  20  minutes,  strain,  and  add  3  quarts  red  mordant  No.  146,  6  lbs.  alum  ;  heat  till  clear, 
and  add  4  gallons  thick  gum-substitute  water. 

No.  103.  Tin  Pulp. — To  protochloride  of  tin  solution  add  as  much  yellow  prussiatc  of 
potash  in  solution  as  will  precipitate  all  the  tin  as  ferroprussiate  ;  this  is  washed  by  decan- 
tation,  and  filtered  to  a  stiff  paste. 

No.  104.  Light  Blue  for  Machine. —  1  gallon  dark  blue  No.  99,  3  gallons  4-lb.  gum- 
substitute  water. 

No.  105.  Green.,  {Machine.) — 7  gallons  Persian-berry  liquor  at  12°  T.,  15  lbs.  yellow 
prussiate  of  potash,  8  lbs.  alum,  28  lbs.  gum-substitute ;  boil,  and  add  2  lbs.  nmriate-of-tin 
crystals,  2  lbs.  oxalic  acid. 

No.  106.  Fink.,  {Machine.) — 4  gallons  cochineal  liquor  at  6°  T.,  2  lbs.  alum,  2  lbs.  bitar- 
trate  of  potash,  8  oz.  o.xalic  acid,  4   gallons  thick  gum-Senegal  water. 

No.  107.  Purple,  {Machine.) — 2  gallons  logwood  liquor  at  12°  T.,  12  oz.  alum,  8  oz. 
red  prussiate  of  potash,  4  oz.  oxalic  acid,  8  gallons  gum-substitute  water.  If  for  block,  add 
12  gallons  gum  water  instead  of  8  gallons. 

No.  108.  Dark  Red,  {3fnchine.) — 8  quarts  Sapan  liquor  at  12°  T.,  2  quarts  bark  liquor 
at  8°  T.,  2  quarts  nitrate  of  alumina  No.  109,  G^-  lbs.  starch,  1  lb.  gum-substitute,  4  quarts 
water,  4  oz.  chlorate  of  potash,  12  oz.  alum. 

No.  109.  Nitrate  of  Alumina. — S  gallons  boiling  water,  24  lbs.  nitrate-of-lcad  crystals, 
24  lbs.  alum,  5  lbs.  carbonate-of-soda  crystals ;  let  settle,  and  use  the  clear. 

No.  110.  Blue  Standard. — 1  gallon  water,  12  oz.  alum,  4}  oz.  oxalic  acid,  If  lbs.  yellow 
prussiate  of  potash,  1  gallon  gum-substitute  water. 

No.  111.  Lai'cnder  Liquor — 2  gallons  red  liquor  at  18°  T.,  6  lbs.  ground  logwood  ;  let 
steep  for  48  hours,  then  strain  off  the  liquor. 

No.  112.  Lavender. — 4  gallons  lavender  liquor  No.  111,4  gallons  blue  standard  No. 
110,  from  24  to  48  gallons  gum  water,  according  to  shade  wanted. 

No.  113.  Drab. — 4  gallons  lavender  liquor,  4  gallons  blue  standard,  1  gallon  bark  liquor 
at  8°  T.,  from  40  to  70  gallons  gum  water,  according  to  shade  wanted. 

No.  114.  Stone. — 4  gallons  lavender  liquor  No.  Ill,  6  gallons  blue  standard  No.  110,  1 
gallon  bark  liquor  at  12°  T.,  reduced  same  as  drab. 

No.  115.  Sar/e  Green  for  Blotch  Grounds. — 2  gallons  yellow  No.  48,  2  gallons  blue 
standard  No.  110,  from  28  to  56  gallons  gum  water,  according  to  shade  wanted. 

No.  116.    Yellow. — 4  gallons  berry  liquor  at  12°  T.,  1^  lb.  alum. 

No.  117.  Brown  Standard. — 14  quarts  bark  liquor  at  12°  T.,  3.}  quarts  Sapan  liquor  at 
12°  T.,  \k  quarts  logwood  liquor  at  12°  T.,  12  quarts  S-lb  gum-substitute  water,  3^1-  lbs. 
alum,  2  oz.  chlorate  of  potash,  5  oz.  red  prussiate.  All  shades  of  light  browns  arc  made 
from  this  by  reducing  with  gum-substitute  water,  according  to  shade  wanted. 

No.  118.  Ye'.low. — 4  gallons  bark  at  8°  T.,  2  quarts  red  liquor  at  18°  T.,  2  quarts  ni- 
trate of  alumina  No.  109,  12  oz.  tin  crystals,  5  lbs.  starch. 

No.  119.  Green  for  Block. — 28  lbs.  yellow  prussiate  of  potash,  6  gallons  hot  water;  iu 
a  separate  vessel,  10  gallons  6-lb.  gum-Senegal  water,  2  gallons  water,  1  gallon  muriate  of 
tin  at  120°  T.  ;  mix  the  prussiate  solution  with  the  tin  and  gum  by  pouring  one  into  the 
other,  and  violently  agitating ;  when  quite  fiae  and  free  from  floeculent  matter,  add  12  gal- 
lons berry  liquor  at  10°  T.,  then  add  12  lbs.  and  2|  lbs.  oxalic  acid,  dissolved  in  5  gallons 
water,  then  3  quarts  acetic  acid,  and  2^  gills  exti-act  of  indigo. 

No.  120.  Brown. — 6  quarts  berry  liquor  at  20°  T.,  6  quarts  Brazil  wood  liquor  at  8°  T., 
3  lbs.  alum,  3  quarts  lavender  liquor,  6  quarts  6-lb.  gum-Senegal  water,  24  oz.  nitrate  of 
copper  at  100°  T. 

After  printing,  the  pieces  are  hung  for  some  hours  to  equalize  their  temperature,  and 
are  then  steamed. 

There  are  two  methods  of  steaming  now  commonly  employed : — the  column  and  the 
cliest.  The  column  is  a  hollow  cylinder  of  copper,  from  3  to  5  inches  in  diameter,  and 
about  44  inches  long,  perforated  over  its  whole  surf\ice  with  holes  of  about  Vie  of  an  inch, 
placed  about  \  of  an  inch  asunder.  A  circular  plate,  about  9  inches  diameter,  is  soldered 
to  the  lower  end  of  the  column,  destined  to  prevent  the  coil  of  cloth  from  sliding  down  off 
the  cylinder.  The  lower  end  of  the  column  terminates  in  a  pipe,  mounted  with  a  stopcock 
for  regulating  the  admission  of  steam  from  the  main  steam  boiler  of  the  factory.  In  some 
cases,  the  pipe  fixed  to  the  lower  surface  of  the  disk  is  made  tapering,  and  fits  into  a  coni- 
cal socket,  in  a  strong  iron  or  copper  box,  fixed  to  a  solid  pedestal ;  the  steam  pipe  cntt  ni 
into  one  side  of  that  box,  and  is  provided,  of  course,  with  a  stopcock.  The  condensed 
water  of  the  column  falls  down  into  that  chest,  and  maybe  let  ofi"by  a  descending  tube  and 
a  stopcock.  In  other  forms  of  the  column,  the  conical  junction  pipe  is  at  its  top,  and  fits 
there  into  an  inverted  socket  connected  with  a  steam  chest,  while  the  bottom  has  a  very 
small  tubular  outlet,  so  that  the  steam  may  be  exposed  to  a  certain  pressure  in  the  column 
when  it  is  encased  with  cloth.  , 

The  pieces  are  lapped  round  this  column,  but  not  in  immediate  contact  with  it ;  for  the 
copper  cylinder  is  first  enveloped  in  a  few  coils  of  blanket  stuff,  then  with  several  coils  of 


272  CALICO  FEINTING. 

white  calico,  next  with  the  several  pieces  of  the  printed  goods,  stitched  endwise,  and  lastly, 
with  an  outward  mantle  of  white  calico.  In  the  course  of  the  lapping  and  unlapping  of  such 
a  length  of  webs,  the  cylinder  is  laid  in  a  horizontal  frame,  in  which  it  is  made  to  revolve. 
In  the  act  of  steaming,  however,  it  is  fixed  upright,  by  one  of  the  methods  above  described. 
The  steaming  lasts  for  20  or  30  minutes,  according  to  the  nature  of  the  dyes ;  those  which 
contain  much  solution  of  tin  admit  of  less  steaming.  Whenever  the  steam  is  shut  off,  the 
goods  must  be  immediately  uncoiled,  to  prevent  the  chance  of  any  aqueous  condensation. 
The  unrolled  pieces  are  free  from  damp,  and  require  only  to  be  exposed  for  a  few  minutes 
in  the  air  to  appear  perfectly  dry.  Were  water  condensed  during  the  process,  it  would  be 
apt  to  make  the  colors  run. 

The  other  method  of  steaming,  and  the  one  now  most  generally  employed,  is  that  of  the 
chest.  This  is  a  rectangular  iron  chamber,  with  penthouse  top ;  its  dimensions  are  about 
12  feet  in  length  by  6  feet  in  width,  by  9  feet  in  height  at  the  highest  part.  It  is  provided 
with  closely-folding  doors  at  one  end,  with  a  cross  bar,  which  can  be  fastened  with  wedges 
or  screws.  There  is  a  perforated  false  bottom,  at  the  same  level  as  the  room  in  which  the 
steam  chest  stands  ;  underneath  the  false  bottom  is  a  perforated  pipe,  running  round  three 
sides  of  the  chest ;  this  pipe  admits  the  steam,  which  is  furtlier  diHuscd  by  the  holes  in  the 
false  bottom.  On  the  false  bottom  is  laid  a  pair  of  rails  parallel  with  the  sides  of  the  chest ; 
these  rails  are  continued  outside  the  chest  into  the  room,  the  parts  next  the  chest  for  about 
3  feet  being  hinged  so  as  to  be  moved  on  one  side  when  the  doors  are  opened  or  shut.  Upon 
the  rails  moves  a  rectangular  frame  of  wood,  which  just  fits  inside  the  chest,  and  stands  as 
high  as  the  commencement  of  the  slope  of  the  roof.  This  frame,  when  drawn  out  into  the 
room,  is  filled  with  pieces  in  the  following  manner  : — They  are  first  wound  on  an  open  reel, 
one  by  one,  the  selvages  of  each  fold  being  kept  as  parallel  as  possible.  The  piece  is  then 
slid  oif  the  end  of  the  reel,  pulled  flat,  and  a  needle  and  thread  passed  through  all  the  sel- 
vages of  one  side,  and  loops  made,  through  which  are  passed  wooden  rods,  which  rest  on 
the  sides  of  the  carriage.  The  pieces  being  thus  suspended  with  selvages  downwards,  the 
carriage,  being  filled  with  the  rods,  is  run  into  the  chest,  the  doors  firmly  shut,  and  steam 
turned  on,  the  steam  escaping  by  a  safety  valve.  They  hang  thus  for  45  minutes,  are  taken 
out,  unfolded,  and  loosely  folded  for  washing  off.  They  are  next  stitched  end  to  end,  and 
passed  through  a  cistern  with  water,  from  that  into  a  cistern  containing  a  very  weak  solu- 
tion of  bichromate  potash  ;  they  are  then  put  into  a  washing  machine,  hydro-extracted, 
starched,  and  dried. 

The  colors  that  are  fixed  by  steaming,  may,  with  one  or  two  exceptions,  be  described  as 
colored  lakes  temporarily  held  in  solution  by  acids,  and  during  the  steaming,  the  cloth  grad- 
ually withdraws  these  hikes  from  solution,  the  acid  being  either  dissipated  or  so  modified 
as  to  be  incapable  of  holding  the  lakes  dissolved.  The  state  of  the  steam  is  an  important 
matter.  It  is  not  the  heat  alone  that  produces  the  effect ;  for  it  may  easily  be  demonstrated 
that  heating  cloth,  when  printed  and  drkil,  has  no  effect  whatever.  The  steam,  to  be 
effective,  must  be  as  saturated  with  moisture  as  possible,  and  for  this  reason  the  steaming 
apparatus  should  never  be  near  the  boiler :  it  is  no  disadvantage  for  the  steam  to  travel  a 
considerable  distance  before  being  applied.  In  some  print  works  the  steam  is  made  to  pass 
through  water  in  a  vessel  placed  below  the  steam  chest,  so  that  it  arrives  in  the  chest  per- 
fectly saturated  with  water.  At  the  same  time,  the  steam  must  not  be  of  so  low  tension  as 
to  cause  a  deposit  of  moisture  on  the  pieces,  which  would  be  very  injurious,  by  causing  the 
colors  to  run  or  mix.  Steam  blue  depends  for  its  fixation  on  the  decomposition  of  ferrocy- 
anic  acid  by  the  high  temperature  and  presence  of  vapor  water  into  white  insoluble  ferrocy- 
anide  of  iron  and  potassium,  which,  by  acquiring  oxygen  from  the  air  or  during  the  wash- 
ing-off,  becomes  Prussian  blue.  The  shade  of  it  is  much  modified  by  the  oxide  of  tin  in  the 
cloth,  and  the  prussiate  of  tin  that  forms  part  of  the  color.  It  appears  that  tin  substitutes 
iron,  forming  a  compound  ferrocyanide  of  tin  and  iron,  or  a  ferro-stanno-cyanide  of  iron, 
which  is  of  a  deep  violet-blue  color.  Greens  are  mixtures  of  yellow  lakes  with  the  Prussian 
blue,  formed  l)y  decomposition.  In  both  these  colors  there  is  a  large  quantity  of  hydrocy- 
anic acid  disengaged  during  the  steaming  ;  steam  being  decomposed,  its  hydrogen  going  to 
form  hydrocyanic  acid. 

Mousseline  de  laines  are  treated  somewhat  in  the  same  manner,  the  preparation  of  the 
cloth  being  different,  and  the  colors  are  made  in  such  a  manner  as  to  fix  equally  on  both 
the  wool  and  the  cotton  of  the  fabric.  The  steaming  and  washing-off  is  nearly  the  same  as 
for  calicoes.     The  following  is  the  method  in  detail : — 

The  cloth  is  first  well  bleached  (See  Bleaching)  and  sulphured.  This  operation  is  usu- 
ally performed  by  hanging  the  goods  in  a  stone  or  brick  chamber.  Trays  of  sulphur  being 
lighted,  the  door  is  closed  tight,  and  the  pieces  stay  in  the  sulphurous  gas  for  several  hours, 
and  are  then  removed  and  washed.  An  improvement  on  this  method  was  patented  by  John 
Thorn,  and  is  here  shown : — 

TJionCs  Sulphurinr/  Appnratns. — Fir/.  138.  A  is  the  roof,  made  of  sheet  lead,  4  lbs.  to 
the  foot,  n  is  a  lead  pipe,  of  one  inch  diameter,  t'aking  off  the  excess  of  sulphurous  acid  to 
the  flue,     c  and  c  are  rolls  of  pieces,  going  in  on  one  side  and  coming  oft"  at  the  other,     d 


CALICO  PKINTING. 


273 


and  D,  rollers  of  wood,  three  inches  in  diameter,  with  iron  centres  at  the  ends,     e  and  e, 
tiles,  as  in  malt  kilns,  to  let  the  gas  pass  up  through  to  the  cloth. 


138 


Fir/.  139  shows  the  chamber ;  it  is  six  feet  in  length  by  four  feet  in  breadth,  and  about 
five  feet  high.  There  are  two  windows,  which  are  placed  opposite  each  other,  f  is  a  cast- 
iron  tray  for  burning  the  sulphur.  It  is  placed  on  a  flag,  inclining  towards  the  chamber  at 
about  one  inch  to  a  foot.  It  is  furnished  with  a  slide,  on  which  to  put  the  sulphur  to  be 
pushed  in,  and  to  admit  what  air  may  be  wanted.  The  space  for  air  may  be  from  half  an 
inch  to  an  inch  wide.     It  costs  £18  to  £20. 

Preparation. — Pad  the  pieces,  previously  well  bleached,  (see  Bleaching,)  in  a  wooden 
padding  machine  through  stannate  of  soda  at  10°  twice  over,  then  pass  through  a  cistern 
-  with  rollers,  containing  dilute  sulphuric  acid  at  3°  T.,  wash  gently,  and  partially  dry,  then 
pad  through  sulphomuriate  of  tin  at  4°  T.  twice. 

No.  121.  Stdpkomuriale  of  Tin. — 3  quarts  muriate  of  tin  at  120°  T.,  1  quart  sulphuric 
acid  at  170'  T.,  mixed  together  gradually,  and  4  quarts  muriatic  acid  added  ;  reduce  to 
4°  T. 

Run  from  this  without  washing  into  a  large  cistern  with  roller^  containing  dilute  chloride 
of  lime  at  ^°  T.,  then  wash,  put  in  the  hydro-extractor,  and  dry.  When  wanted  for  print- 
VoL.  III.— 18 


274 


CALICO  FEINTING. 


in"-,  pad  through  gum-Senegal  water  at  8  oz.  to  the  gallon,  and  dry.  After  printing,  they 
are  hun''  the  same  as  calicoes  to  equalize  the  temperature,  then  hung  in  the  steam  chest  in 
the  same  manner  as  calicoes,  and  steamed  45  minutes.  After  steaming,  they  are  unrolled 
and  loosely  folded  for  washing-off,  which  is  done  by  wincing  over  a  reel  in  a  pit  of  water 
gently  for  J  of  an  hour,  then  transferred  to  a  washing  machine  or  large  automatic  wince 
reel,  and  washed  till  no  more  colored  liquor  comes  away,  then  hydro-extracted,  and  dried 
over  the  steam  cylinders.  After  drying,  it  is  found  advantageous  to  hang  the  pieces  in  a 
cool  room,  with  covered  shutter  sides,  for  a  day  or  two,  so  that  they  may  imbibe  a  little 
moisture,  and  the  colors  appear  richer.  Tlie  wool  in  mousseline  de  laines  is  apt  to  be  par- 
tially decomposed  during  steaming,  and  sulphuretted  hydrogen  liberated,  which  decomposes 
the  metallic  salts,  such  as  nitrate  of  copper,  used  in  some  colors,  and  produces  a  very  di.sa- 
greeable  effect,  termed  silvering.  To  avoid  this,  it  is  now  customary  to  wind  on  the  reel 
for  steaming,  at  the  same  time  as  tlie  printed  piece,  a  gray  or  unbleached  piece,  which  has 
been  padded  in  a  weak  solution  of  acetate  of  lead,  and  dried.  By  this  means  the  printed 
piece  is  steamed  in  contact  with  the  prepared  piece,  and  any  sulphuretted  hydrogen  that 
may  be  disengaged  is  immediately  absorbed  by  the  acetate  of  lead. 

The  following  are  the  colors  used  in  mousseline  de  laine  printing : — 

No.  122.  Dark  Red. — 4  gallons  cochineal  liquor  at  10"  T.,  7  lbs.  starch  ;  boil,  and  when 
cooled  to  180'  F.,  add  IJ  lbs.  oxalic  acid,  and  when  this  is  dissolved,  IJ  lbs.  rauriate-of-tin 
crystals. 

No.  123.  Chocolate. — 6  gallons  Sapan  liquor  at  12°  T.,  2  gallons  logwood  liquor  at  12° 
T.,  1  gallon  bark  liquor  at  12'  T.,  16  lbs.  starch ;  boil,  and  add  5f  lbs.  alum,  12  oz.  chlorate 
of  potash,  41  lbs.  red  prussiate  of  potash. 

No.  124."  Yellow. — 4  gallons  berry  liquor  at  10'  T.,  5|  lbs.  starch,  1  lb.  pale  British 
gum  ;  boil,  and  add  1}  lbs.  muriate-of-tin  crj'stals. 

No.  125.  Bark  or  Royal  Blue. — 6  gallons  water,  6|  lbs.  starch,  1\  lbs.  sal  ammoniac  ; 
boil  well,  and  add  6  gallons  tin  pulp  No.  103;  mix  well  into  the  paste,  and  add  16  lbs. 
pounded  yellow  prussiate  of  potash,  8  lbs.  red  prussiate,  24  lbs.  tartaric  acid,  and  1^  lbs. 
oxalic  acid  previously  dissolved  in  4  pints  hot  water. 

No.  126.  Pale  Blues  are  made  from  the  dark  blue  No.  125,  by  reducing  with  gum-sub- 
stitute water,  say  1  of  dark  blue  and  7  of  gum  water  for  pale  blue,  for  two  blues,  and  1  of 
dark  blue  and  14  of  gum  water  for  blotch  or  ground  blue. 

No.  127.  Green. — 4  gallons  berry  or  bark  liquor  at  12°  T.,  3  lbs.  alum,  6  lbs.  starch ; 
boil,  and  add  6  lbs.  powdered  yellow  prussiate  of  potash,  1  lb.  muriate  of  tin  crystals,  1  lb. 
oxalic  acid,  and  2f  pints  extract  of  indigo. 

No.  128.  Pale  Green. — 3  quarts  berry  liquor  at  6°  T.,  IJ  lbs.  yellow  prussiate  of  potash, 
0|  oz.  alum,  f  pint  acetic  acid,  16  quarts  4-lb.  gum-Senegal  water,  8  oz.  weight  muriate  of 
tin  liquor  at  12°  T.,  f  pint  extract  of  indigo. 

No.  129.  Dark  Broivn. — 21  quarts  Sapan  liquor  at  8°  T.,  1  pint  logwood  liquor  at  12° 
T.,  5  quarts  bark  liquor  at  10°  T.,  12  oz.  alum,  1  oz.  chlorate  of  potash,  6  lbs.  gum-substi- 
tute ;  boil,  and  add  4  oz.  red  prussiate  of  potash,  2  oz.  oxalic  acid. 

No  130.  Pale  Browns  arc  made  from  the  dark  brown  No.  129,  by  reducing  with  gum 
water,  say  1  to  3  or  1  to  5. 

No.  131.  Pale  Red. — 1  lb.  fine  ground  cochineal,  1  lb.  liquor  ammonia,  specific  gravity 
0-88  ;  put  in  a  jar  with  tight-fitting  cover,  which  may  be  luted  down  ;  keep  in  a  warm  place 
for  48  hours,  then  mix  with  2  gallons  boiling  water,  and  simmer  in  a  mug  down  to  1  gallon, 
then  strain  off,  wash  the  cochineal  with  a  little  water,  and  strain  again  ;  to  the  liquor  made 
up  to  1  gallon  add  4  oz.  alum,  4  oz.  muriate  of  tin  crystals,  4  oz.  oxalic  acid,  and  1  gallon 
6-lb.  gum-Senegal  water. 

No.  132.  Scarlet. — 2  gallons  cochineal  liquor,  at  12°  T.,  4  lbs.  starch  ;  boil,  and  add  4 
oz.  oxalic  acid,  4  oz.  binoxaUuc  of  potash,  8  oz.  pink  salts,  (double  permuriate  of  tin  and 
ammonia,)  and  8  oz.  muriate-of-tin  crystals. 

No.  133.  Scarlet. — 3  gallons  standard  No.  136,  1  quart  berry  liquor  at  10°  T.,  4|  lbs. 
starcli ;  boil,  and  add  8  oz.  binoxalate  of  potash,  8  oz.  oxalic  acid,  li  lbs.  pink  salts,  ^  pint 
oxymuriatc  of  tin  at  120°  T. 

No.  134.  Standard. — 2  lbs.  fine  ground  cochineal,  6  quarts  water,  1  quart  red  liquor 
at  20f  T.,  4  oz.  nitric  acid,  2  oz.  oxalic  acid ;  boil  20  minutes,  and  strain  off. 

No.  135.  Medium  Blue. — 6  gallons  standard  blue  No.  136,  1^  quarts  oxymuriate  of  tin 
at  120°  T.,  added  gradually,  and  beaten  fine,  then  2^  quarts  extract  of  indigo. 

No  136.  Standard  Blue. — 10  l))s.  yellow  prussiate  of  potash,  3  lbs.  alum,  2  lbs.  oxalic 
acid,  4  gallons  water,  4  gallons  G-lb.  gum  water. 

No.  137.  Medium  Green. — 8  quarts  berry  liquor  at  8°  T.,  3  lbs.  yellow  prussiate  of  pot- 
ash, 1 1  lbs.  alum,  7  quarts  6-lb.  gum  water,  1  quart  water,  1  quart  acetic  acid,  14  oz.  weight 
muriate-of-tin  liquor,  1  pint  extract  of  indigo. 

No.  138.  Lilac. — 8  qu»ts  lavender  liquor  No.  Ill,  6  oz.  oxalic  acid,  2  oz.  measure  ex- 
tract of  indigo. 

No.  130.  Lavender  Lujnor. — 2  gallons  red  liquor,  10  lbs.  ground  logwood  ;  steep  12 
hours,  and  strain  off. 


CALICO  PRINTING.  275 

No.  140.  Dove. — 6  quarts  blue  for  doves  No.  141,  4  quarts  lavender  liquor  No.  Ill,  8 
quarts  6-lb.  gum-Senegal  water. 

No.  141.  Blue  for  Doves. — 5  quarts  water,  2  lbs.  yellow  prussiate  of  potash,  2  lbs.  alum, 
5  quarts  6-lb.  gum  water,  1  pint  extract  of  indigo. 

No.  142.  Orange. — 3  gallons  berry  liquor  at  10°  T.,  9  lbs.  gum-Senegal,  3  pints  red 
mordant  No.  146,  12  oz.  muriate-of-tin  crystals;  boil  15  minutes. 

No.  143.  Drab  Standard. — 6  quarts  purple  liquor  No.  144,  1  quart  bark  liquor  at  10° 
T.,  ^  pint  red  liquor  at  20°  T.,  J  pint  extract  of  indigo. 

Drabs  are  made  from  this  by  reducing  with  gum  water  about  1  to  3. 

No.  144.  Purple  Liquor. — 1  gallon  lavender  liquor  No.  Ill,  3  oz.  oxalic  acid. 

No.  145.  Silver-drab  Standard. — 3  quarts  gall  liquor  at  12°  T.,  2  quarts  standard  blue 
No.  136,  1  quart  lavender  liquor  No.  111. 

Colors  reduced  with  gum  water  from  this,  1  to  2  or  3. 

No.  146.  Red  Afordant. — 1  gallon  water,  6  lbs.  alum,  3  lbs.  white  acetate  of  lead  ;  stir 
till  dissolved,  let  settle,  and  use  the  clear. 

No.  147.  Buff  Standard. — 1  quart  cochineal  liquor  at  8°  T.,  3|  quarts  berry  liquor  at 
10°  T.,  1  quart  red  mordant  No.  146,  20  oz.  oxalic  acid. 

Colors  reduced  from  this  with  gum  water. 

No.  148.  Olive. — 1  quart  lavender  liquor  No.  Ill,  2  quarts  berry  liquor  at  10°  T.,  2 
quarts  8-lb.  gum-Senegal  water. 

In  mousseline-de-laine  printing  success  depends  more  on  the  bleaching  and  preparing 
of  the  cloth  than  in  any  other  style.  To  Mr.  John  Mercer  is  due  the  merit  of  having  effected 
an  improvement  in  the  preparation  of  woollen  fabrics,  the  importance  of  which  can  hardly 
be  overrated.  Before  his  discovery  of  the  power  of  prepared  wool  to  absorb  chlorine, 
mousseline  de  laines  could  only  be  effectively  printed  by  block,  which  allows  a  large  body 
of  color  to  be  laid  on,  and  the  fibre  supersaturated  with  it.  Machine  colors  were  meagre 
and  dull.  But  mousseline  de  laines  prepared  with  tin,  and  then  subjected  to  the  action  of 
chlorine  gas,  (as  in  the  process  given  above,  where  the  acid  salt  of  tin  remaining  in  the  cloth, 
disengages  chlorine  from  the  chloride  of  lime,)  have  their  power  of  absorbing  and  retaining 
color  considerably  enhanced.  The  exact  part  the  chlorine  plays  is  not  well  known,  probably 
a  compound  similar  to  the  chloro-protein  of  Mulder  is  formed.  The  effect  produced  is  not 
one,  as  might  be  supposed,  of  oxidation ;  but  apparently  a  merely  heightened  power  of  the 
wool  to  assimilate  coloring  matter.  Wool  subjected  to  chlorine  without  tin  is  much  im- 
proved in  its  capacity  for  color,  but  nothing  like  the  same  when  prepared  with  tin  also.  The 
whole  of  the  chlorine  may  be  removed  from  the  cloth  by  passing  through  an  alkali,  which 
renders  it  necessary  to  give  the  stannate-of-soda  padding  previously  to  the  chlorinating.  It 
may  fairly  be  assumed  that  the  development  of  mousseline-de-laine  printing  by  cylinder  to 
the  present  perfection  is  due  in  a  great  measure  to  this  chlorinating  process.  It  ought  also 
to  be  stated  that,  with  rare  liberality,  Mr.  Mercer  gave  the  discovery  to  the  trade,  reserving 
for  himself  no  right  whatever. 

Ninth  Style :  Spirit  Colors. 

Topical  colors  of  great  brilliancy,  but  possessed  of  very  little  solidity,  are  made  some- 
what like  steam  colors,  but  with  much  larger  proportions  of  "  spirits,"  by  which  term  is 
meant  the  metallic  salts  and  acids,  which,  combining  with  the  dyestuff  decoctions,  give  the 
peculiar  tone  and  vivacity  to  these  colors.  These  colors,  from  the  large  admixture  of  these 
salts,  are  necessarily  very  acid,  and  cannot  be  steamed  without  the  destruction  of  the  cloth. 
They  are  merely  gently  dried  after  printing,  and  hung  in  the  ageing  room  for  several  hours, 
then  rinsed  in  water,  washed,  and  dried. 

The  following  are  examples  of  spirit  colors : — 

No.  149.  Black. — 1  gallon  logwood  liquor  at  8°  T.,  1  gallon  water,  10  oz.  copperas,  3 
lbs.  starch  ;  boil,  and  add  ^  pint  pernitrate  of  iron  at  80"  T. 

No.  150.  Pink. — 1  gallon  Sapan  liquor  at  8°  T.,  1  gallon  water,  2  lbs.  common  salt,  1^ 
lbs.  starch;  boil,  cool,  and  add  1  pint  oxymuriate  of  tin  at  120°  T.,  3  oz.  measure  nitrate  of 
copper  at  80°  T. 

No.  151.  Blue. — l^gallon  water,  1  lb.  yellow  prussiate  of  potash,  6  oz.  alum,  1|  lbs. 
starch;  boil,  and  add  |  pint  nitrate  of  iron  at  80°  T.,  H  gills  oxymuriate  of  tin  at  120°  T. 

No.  152.  Brown. — 1  gallon  berry  liquor  at  8°  T.,  2  lbs.  ligiit  British  gum  ;  boil,  and 
add  1  lb.  muriate-of-tin  crystals,  2  quarts  spirili  pink  No.  150,  2  quarts  spirit  purple 
No.  153. 

No.  153.  Purple. — 1  gallon  logwood  liquor  at  8°  T.,  1  gallon  water,  10  oz.  copperas,  2 
lbs.  starch ;  boil,  and  add  1  pint  protoniuriate  of  iron  at  80°  T.,  1  pint  oxymuriate  of  tin  at 
120°  T. 

No.  154.  Orange. — li  gallons  berry  liquor  at  8°  T.,  12  lbs.  light  British  gum  ;  boil,  and 
add  6  lbs.  muriate-of-tin  crystals,  4  gallons  spirit  pink  No.  160. 

No.  155.   Chocolate. — 2|  gallons  spirit  pink  No.  15(\  1  gallon  spirit  blue  No.  151. 

No.  156.  Red. — 3  gallons  Sapan  liquor  at  4°  T.,  1  lb.  sal  ammoniac,  1  lb.  verdigris,  4i 
lbs.  starch;  boil,  cool,  and  add  5  lbs.  pink  salts,  1  lb.  o.valic  acid. 


276  CiU^ICO  PRINTING. 

No.  157.  YellouK — 1  gallon  berry  liquor  at  10°  T.,  -i  lb.  alum,  1  lb.  starch;  boil,  and 
add  1  pint  muriate-of-tiu  liquor  at  120"  T. 

Xo.  158.   Green. — 1  gallon  spirit  blue  No.  151,  1  gallon  spirit  yellow  No.  157. 

Xo.  159.  Spirit  Pink  for  Blocking  3Iadder  Work. — 4^  gallons  Brazil  wood  liquor  at 
lu~  T.,  9  lbs.  pink  salts,  3  lbs.  sal  ammoniac,  2  lbs.  sulphate  of  copper,  5 J  oz.  oxalic  acid, 
dissolved  in  1  pint  water,  4^  gallons  of  6-lb.  gum-Senegal  water,  1^  quarts  oxymuriate  of  tin 
at  120°  T. 

Tenth  Style  :  Bronzes. 

The  cloth  is  padded  in  solution  of  sulphate  of  manganese,  the  strength  of  which  deter- 
mines the  sliade  of  brown  produced  ;  for  a  medium  shade  of  brown,  suitable  for  discharge 
colors,  the  liquor  may  be  80°  T. 

After  padding  and  drying,  pad  the  pieces  through  caustic  soda  at  24°  T.,  and  again 
through  caustic  soda  at  12°  T.,  wince  well  in  water,  and  then  in  solution  of  chloride  of  lime 
at  2°  T.  till  perfectly  brown  ;  wash  well  in  water,  and  dry. 

The  colors  for  printing  on  this  dyed  ground  are  so  made  as  to  discharge  the  brown  and 
substitute  their  own  color  in  place  of  it. 

No.  11)0.  Blue  Discharge . — («)  6  gallons  water,  Sf  lbs.  yellow  prussiate  of  potash,  10 
lbs.  starch,  6  lbs.  light  British  gum  ;  boil,  and  add  12  lbs.  tartaric  acid,  C  lbs.  oxalic  acid, 
1-J  quarts  pemitrate  of  iron  ;  then  take  (6)  5  quarts  of  this  standard,  '6  c^uarts  muriate  of  tin 
at.l20°T. 

Xo.  IGl.  Discharge  Yellow  for  Chroming. — (a)  1  gallon  water,  5  lbs.  nitrate  of  lead,  4 
lbs.  light  British  gum  ;  boil,  and  add  4  lbs.  tartaric  acid  ;  then  take  {h)  3  quarts  this  stand- 
ard, 1  quart  muriate  of  tin  at  120°  T. 

No.  1G2.  Discharge  Green. — 2  quarts  yellow  standard  No.  161  (a),  1  quart  blue  stand- 
ard Xo.  160  (a),  1  quart  muriate  of  tin  at  120°. 

Xo.  163.  Discharge  Pink. — {a)  2  gallons  Brazil-wood  liquor  at  12°  T.,  4  oz.  sulphate 
of  copper,  4  oz.  sal  ammoniac,  4  lbs.  starch  ;  boil,  and  add  8  oz.  measure  oxymuriate  of  tin 
at  120°  T. ;  then  take  (6)  2quarts  of  this  standard,  1  cjuart  muriate  of  tin  at  120°. 

X'o.  164.  White  DUcharge. — 2  gallons  water,  8  lbs.  light  British  gum;  boil,  and  add  8 
lbs.  tartaric  acid,  and  1  gallon  muriate  of  tin  at  120°  T. 

J?Zaeyl-.— Spirit  black  No.  149. 

After  printing,  hang  for  a  few  hours,  and  wince  in  a  pit  with  water  freely  flowing  into 
it;  then  wince  in  chalky  water,  again  in  water,  then  wince  in  bichromate  of  potash  at  4°  T., 
to  raise  the  green  and  yellow  ;  wash  and  dry. 

The  discharging  agent  in  these  colors  is  the  protomuriato  of  tin,  which,  by  its  superior 
attraction  for  oxygen,  robs  the  peroxide  of  manganese  of  a  portion.  The  protoxide  of  man- 
ganese formed  by  this  change  Ijcing  then  soluble  in  the  acid,  and  subsequently  washed 
away,  the  pigment  Prussian  blue  and  chromate  of  lead,  also  the  Brazil  lake,  beipg  left  fixed 
in  the  discharged  place. 

Eleventh  Style  :  Pigment  Printing. 

In  this  style,  the  ordinary  pigments,  such  as  used  in  oil-painting,  arc  mechaiiically  at- 
tached to  the  cloth  by  a  species  of  cementing.  The  first  fixing  vehicle  used  was  a  solution 
of  caoutchouc  in  naplitha,  which  was  mixed  with  the  pigment  so  as  to  make  colors  of  suffi- 
cient viscosity  to  print.  The  naphtha  was  then  driven  off  by  steaming,  and  the  pigment  was 
thc'u  cemented  to  the  cloth  by  a  film  of  caoutchouc.  This  method  makes  very  fast  colors, 
not  affected  by  soaping  and  moderate  friction  ;  but,  unfortunately,  the  naphtha  volatilizing 
during  the  printing  process,  rendered  the  use  of  it  too  dangerous,  and  after  it  was  found 
that  explosions  of  the  naphtha  Aapor  frequently  took  place,  calico  printers  turned  their  at- 
tention to  some  other  fixing  vehicle.  Animal  substances,  of  which  the  white  of  eggs  is  the 
type,  and  which,  soluble  in  water,  are  coagulated  by  heat,  are  now  usually  employed.  Of 
these  three  may  be  particularized  : — albumen  of  eggs,  lactarine,  gluten. 

The  first  is  made  by  simply  drying  gently  the  Avhite  of  eggs,  and  powdering. 

The  second  is  made  by  separating  the  solid  part  of  buttermilk,  purifying  it  from  butter 
and  free  acid,  and  drying  it. 

The  third  is  the  residue  of  starch  making  from  wheat  flour  by  tiie  simple  washing  pro- 
cess, the  gluten  being  gently  dried. 

The  two  latter  thickeners  require  a  small  quantity  of  alkali  to  bring  them  in  solution  ; 
they  then  resemble-  albmnen  in  their  power  of  coagulating  by  heat.  There  are  few  colors 
of  this  style  printed,  chiefly  ultramarine  blue  and  carbon  drab. 

Xo.  165.  Ultramarine  Blue,  with  Lactarine. — 1-^  lbs.  lactarine,  3+  pints  water;  mix 
well,  and  add  2i  oz.  measure  liquid  ammonia,  specific  gravity  -880,  5  oz.  measure  caustic 
soda  at  32'  T. ;  then  having  beaten  up  3  lbs.  ultramarine  with  IJ  pints  water,  mix  with  the 
lactarine  solution. 

Xo.  166.  Ultramarine  Blue  v;ith  Alb'umen. — 4  lbs.  iiltramarine,  34^  quarts  water;  mix 
well  and  add  slowly  3  lbs.  albumen  in  powder;  let  it  stand  a  few  hours,  stirring  occasionally  ; 
when  dissolved,  add  1  pint  gum-tnigacanth  water  at  12  oz.  per  gallon. 


CALICO  FEINTING.  2T7 

No.  167.  Ultramarine  Blue  with  Gluten. — 6  lbs.  ultramarine,  5  quarts  water;  mix,  and 
add  gradually  3^  lbs.  ground  gluten  ;  let  it  stand  a  few  minutes,  then  add  1  quart  caustic 
soda  at  16^  T. ;  mix  well,  and  let  it  stand  a  few  hours  before  using. 

Other  shades  of  blue  are  made  by  altering  the  quantity  of  ultramarine. 

Xo.  168.  Drab. — 3  lbs.  lampblack,  3  pints  acetic  acid  at  8'  T.  ;  mix  well  together,  and 
add  a  solution  of  3  lbs.  albumen  in  3  pints  water  ;  then  add  3  pints  12-oz.  gum-tragacanth 
water. 

After  printing  these  colors,  steam  half  an  hour,  wince  in  water,  and  dry.  Colors  fixed 
in  this  manner  are  not  intended  to  resist  severe  treatment. 

No.  169.  Pencil  Blue. — 10  gallons  of  pulp  of  indigo,  containing  40  lbs.  indigo,  40  lbs, 
yellow  orpiment,  11^  gallons  of  caustic  soda  at  70°  T.,  18^  gallons  of  water,  4  lbs.  lime ; 
boil  till  quite  yellow,  when  spread  on  glass;  let  settle,  and  thicken  the  clear  with  120  lbs. 
gum-Senegal. 

Pieces  printed  in  pencil  blue  are  washed  in  water  immediately  after  drying  and  some- 
times soaped  a  little.  Mr.  Bennet  Woodcroft,  struck  with  the  waste  of  indigo  attending 
the  printing  of  either  China  blue  or  pencil  blue,  some  few  years  ago  invented  and  patented 
a  method  of  printing  pencil  blue  by  the  cylinder  machine.  His  plau  was  to  attach  to  an  or- 
dinary single-color  machine  an  Indian-rubl)er  apparatus,  which  enveloped  the  color-box  and 
piece  after  printing  ;  this  apparatus  was  filled  with  coal  gas  :  a  glass  plate  formed  part  of 
the  long  bag  through  which  the  piece  travelled  after  printing,  so  as  to#nable  the  printer  to 
see  the  progress  of  his  work.  By  this  means  the  deoxidized  indigo  was  fairly  applied  to 
the  cloth,  and  oxidation  only  ensued  when  tiie  piece  left  the  apparatus.  The  saving  of  in- 
digo was  said  to  be  considerable,  but  the  plan  was  not  generally  adopted. 

Safflower  Dyei.vg. — The  beautiful  but  fugitive  coloring  matter  of  safflower  is  applied 
in  the  printing  for  dyeing  a  self  color,  generally  after  the  goods  have  been  printed  in  black 
and  red  mordant,  or  black  alone,  aud  dyed  madder  or  garancin.  It  is  commonly  used  for 
cotton  velvets,  the  color  given  to  velvet  appearing  very  brilliant,  from  the  nature  of  the 
cloth.  The  process  is  as  follows  : — Safilpwer  contains  two  distinct  coloi'ing  matters  :  one 
yellow,  being  soluble  in  water,  and  the  other  pink,  insoluble  in  water,  the  latter  only  being 
valuable.  The  yellow  matter  is  therefore  carefully  washed  away.  To  effect  this,  tiie 
safflower  is  put  into  canvas  bags,  4  lbs.  in  a  bag,  and  these  bags  put  into  running  water  and 
occasionally  trodden  upon  till  the  water  runs  off  perfectly  colorless  from  them.  12  of  these 
bags  are  then  emptied  into  a  cask  with  90  gallons  of  water  and  10  quarts  of  pearlash  liquor 
at  24°  T.,  -stirred  up  for  two  hours:  after  standing  all  night,  drain  off  the  liquor,  add  90 
gallons  more  water  and  3  pints  of  pearlash  liquor  ;  stir  up  well,  and  after  standing  for  three 
hours,  drain  off  again  ;  this  weak  liquor  is  saved  for  putting  on  fresh  safflower :  about  30 
gallons  of  the  safflower  solution  is  put  in  a  tub  mounted  with  a  wince  over  it,  and  a  mixture 
of  vinegar  and  lime  juice  is  added  to  it  till  it  is  feebly  acid  to  test  paper.  The  carthamic 
acid,  a  red  coloring  matter  of  safflower,  is  thus  precipitated,  and  remains  as  an  exceedingly 
fine  powder  in  suspension  in  the  liquid ;  2  pieces  of  30  yards  of  velvet  are  put  in  and  winced 
backwards  and  forwards  5  times,  then  wound  upon  the  reel,  and  allowed  to  stay  there  half 
an  hour,  then  wince  5  times  more,  wind  up  again,  and  let  stay  half  an  hour ;  wince  again  5 
times,  aud  wind  up  again  ;  run  off  the  liquor  and  put  in  30  gallons  of  fresh  liquor  and  acid 
as  before  ;  repeat  the  process,  wincing  3  times  of  5  ends  each,  and  letting  lie  wound  on  the 
reel  half  an  hour  each  time  ;  then  take  out  and  wince  in  very  dilute  acetic  acid,  hydro-ex- 
tract, and  dry.  The  pieces,  when  wound  on  the  reel,  should  be  opened  out  flat,  or  they 
might  be  uneven.  Carthamic  acid,  being  of  a  resinous  nature,  has  the  property  of  attaching 
itself  to  cloth,  and  dyeing  in  a  beautiful  pink  like  the  petals  of  a  rose;  this  dye  is  very  fugi- 
tive, strong  sunlight  even  being  injurious  to  it.  There  has  been  no  way  yet  discovered  of 
making  it  permanent. 

MuREXiDE. — The  purpurate  of  ammonia,  or  murexide,  was  discovered  by  Liebig  and 
Wiihler  in  1838,  and  in  its  pure  state  is  one  of  the  most  beautiful  products  of  chemistry. 
It  is  a  crystalline  substance  of  a  beautiful  metallic  green,  like  the  wings  of  the  cantharides 
fly,  and  is  produced  when  uric  acid  is  dissolved  in  dilute  nitric  acid,  the  solution  evaporated 
somewhat,  and  ammonia  added  ;  from  the  beautiful  crimson  liquid,  murexide  crystallizes. 
This  substance  had,  until  a  sljort  time  ago,  no  practical  application.  M.  Albert  Schlum- 
berger  discovered  that  metallic  insoluble  salts,  possessing  all  the  brilliancy  of  the  original 
substance,  could  be  made ;  and  this  fact  was  soon  applied  to  a  practical  use  by  the  French 
chemists,  who  succeeded  in  fixing  a  beautiful  murexide  crimson  upon  cotton  cloth.  The 
process  was  patented  in  this  country  for  French  interests  in  February,  1857,  and  is  now  in 
extensive  use.     The  process  is  as  follows: — 

Print  in  the  color, 

No.  no;  1  gallon  water,  4  lbs.  nitrate  of  lead,  1  lb.  murexide,  1-|  lbs.  starch;  boil. 
After  printing,  hang  a  few  hours,  then  nm  througli  a  cistern  with  rollers  above  and  below, 
and  provided  witli  a  cover,  through  apertures  in  which  the  pieces  enter  and  leave.  This 
cistern  is  kept  supplied  with  atnmoniaeal  gas ;  on  leaving  tliis  cistern,  they  pass  into  water, 
and  from  that  into  a  cistern  charged  with  2  lbs.  bichloride  of  mercury,  4  lbs.  acetate  of 


278  CALICO  PRINTING. 

soda,  i  lb.  acetic  acid,  80  gallons  water;  run  very  slowly  through  this,  wash  and  dry.  In  the 
first  operation  purpurate  of  lead  is  formed  on  the  cloth,  and  in  the  second,  or  changing 
bath,  the  lead  is  wholly  or  partly  removed,  and  oxide  of  mercury  left  in  its  place ;  the  re- 
sulting lake  is  a  color  of  great  brilliancy  and  purit)',  so  much  so  that  few  of  the  ordinary 
colors  will  bear  to  be  looked  at  along  with  it.  Though  perfectly  fast  as  to  soap,  it  appears 
that  strong  sunlight  is  rather  injurious  to  its  permanency. 

A  few  outline  illustrations  of  the  various  madder  styles  will  render  them  more  clear. 

1  a.  Black,  2  reds,  purple  and  brown  on  white  ground.  Print  by  machine  in  colors  4, 
5,  6,  9,  27,  (No.  12  shade,) and  18 ;  age  3  nights,  fly-dung  at  160'  F.,  second  dung  at  150" 
F.,  wash  and  dye  with  French  or  Turkey  madder,  bringing  to  boil  in  If  hours,  and  boiling 
^  hour;  wash  and  soap  twice  at  180°  F.,  wash;  chloride  of  lime  bath,  (see  No.  1  plate  pur- 
ples,) wash  and  dry. 

1  b.  Black,  red,  white,  and  brown  figures,  covered  in  purple.  Print  in  colors  4,  11,  34, 
and  18;  when  dry,  cover  with  a  fine  pattern  in  27,  (12  shade;)  age  3  nights;  fly-dung  at 
170"  F.,  second  dung  at  IGO'  F.,  wash,  dye,  and  clean  as  1  a. 

1  c.  Print  in  colors  6,  7,  (No.  3  shade,)  34 ;  dry  and  cover  in  7,  (6  shade,)  and  blotch 
(or  pad  with  a  roller  engraved  with  a  \)'m,  which  has  the  effect  of  giving  a  uniform  shade) 
in  7,  (10  shade;)  age  three  nights,  and  treat  as  described  under  the  head  Sinss  Pinks. 

1  d.  Some  printers  prefer  to  moi-dant  for  Swiss  pinks  with  alkaline  mordants,  consider- 
ing the  compositionjof  the  colors  to  be  a  guarantee  against  their  containing  iron ;  in  such 
case,  they  print  in  colors  31,  32,  and  35,  covering  in  paler  shades  of  32  after  dyeing;  fly- 
dung  with  3  cwts.  cow-dung,  12  lbs.  sal-ammoniac,  1,000  gallons  water  at  110°  F. ;  second 
dung  with  J  cwt.  cow-dung  at  110°  15  miuutes;  wash  and  dye  as  for  1  c.  In  this  method 
of  mordanting,  the  aluminate  of  soda  that  has  escaped  decomposition  by  the  carbonic  acid 
of  the  air,  is  decomposed  by  the  muriate  of  ammonia,  and  alumina  precipitated  on  the  cloth. 

2  a.  Black,  chocolate,  red,  and  brown  on  white  ground.  Print  in  colors,  5,  13,  (6 
shade,)  14,  and  22;  age  3  or  4  nights;  fly-dung  at  160'  F.,  second  dung  at  160°  F.,  and 
dye  with  chocolate  garancin  or  garauceux,  (see  p.  ^263.) 

2  b.  Black,  chocolate,  red,  and  purple.  Print  as  2  6,  but  dye  with  purple  garancin,  (see 
p.  263.) 

3  a.  For  chintz  work  treat  as  1  a,  then  in  the  parts  of  the  pattern  meant  for  ground- 
ing-in,  block  the  colors  118  yellow,  119  green,  and  129.  If  the  pattern  is  such  as  to  admit 
of  it,  all  these  colors  may  be  printed  at  once  from  one  block,  using  the  tobying  sieve,  p.  226 : 
the  colors,  however,  for  this  method  must  be  thickened  with  gum ;  steam,  &c.,  as  described 
for  steam  colors. 

3  b.  Black,  2  reds,  blue,  green,  and  yellow  covered  in  drab,  or  other  shades.  Print  in 
4,  6,  and  7;  dye,  &c.,  as  1  «;  block-in  color  38  with  a  block  which  covers  all  the  pattern, 
and  also  those  portions  which  are  intended  for  the  steam  colors :  when  this  paste  is  dry, 
cover  by  machine  in  any  of  colors  40  to  47,  age  2  or  three  nights  ;  fly-dung  at  160°  F., 
second  dung  at  150°  F.,  and  dye  with  bark,  or  bark  and  logwood  or  cover  in  color  48,  and 
dye  madder  and  bark  as  No.  6  (p.  251)  for  chocolate;  or  cover  in  color  49  or  51,  and  after 
drying  and  ageing,  wincing  in  chalky  water;  or  in  any  of  colors  55,  56,  or  57,  rinsing  in 
carbonate  of  soda  liriuor  at  5°  T.  when  dry.  After  obtaining  the  ground  shade  by  any  of 
those  processes  and  drying,  ground-in  by  block  colors  118,  119,  and  135,  steam,  wash,  and 
dry. 

3  c.  For  furniture  hangings,  which  are  generally  printed  in  large  groups  of  flowers,  a. 
very  pretty  pea-green  ground  is  often  blocked-iu  as  groundwork,  which  is  made  and  fixed 
as  follows : — 

171.  Pea  Green. — («)Standard  :  6  lbs.  siflphate  of  copper,  1  gallon  water,  4  lbs.  brown 
acetate  of  lead;  di.-vsolve,  let  settle,  and  use  the  clear. — (6)  Color:  2  measures  of  standard, 
1  raea-sure  of  7  lb.  gum-Senegal  solution. 

After  i)rinting,  age  2  nights,  and  pass  through  a  cistern  with  rollers,  set  with  caustic 
potash  liquor  at  15^  T.,  which  has  8  oz.  per  gallon  of  arsenious  acid  dissolved  in  it.  The 
lifjuor  should  be  heated  to  1 10"  F. ;  out  of  this  wash  and  dry. 

Instead  of  blocking-in  steam  blue  and  green,  fast  blue  and  green  are  introduced  where 
the  colors  are  required  to  be  particularly  permanent ;  colors  62  or  63  or  both  are  blocked-in 
and  raised  as  follows: — 5  stone  cistern.s,  each  mounted  with  a  hand  reel,  and  containing 
aliout  200  gallons  each,  are  st>t  with  carbonate-of-soda  liquor,  No.  1  at  7°  T.,  No.  2  at  6°  T., 
No.  3  at  5°  T.,  No.  4  at  4°  T.,  and  No.  5  at  3°  T. ;  wince  10  times  backwards  and  forwards 
in  each  pit,  beginning  with  No.  1,  and  ending  with  No.  5  ;  wince  in  water  and  wash.  The 
change  that  takes  place  here  is  similar  to  that  in  raising  China  l)lues.  The  indigo  is  main- 
tained in  a  deoxidized  state  by  the  protoxide  of  tin  formed,  until  it  has  fixed  itself  in  the 
cloth  by  reoxidation  in  the  air.  Where  fast  green  has  been  printed,  the  pieces  are  winced 
in  bichroiiiate-Oi'-pota.-h  liquor  at  4'  T.  for  10  minutes,  then  washed  and  dried. 

3  e.  Black  and  purple  and  white  with  buff  ground.  Print  in  4  and  27,  (12  shade,)  age, 
dung,  and  dye,  &c.,  as  directed  for  plate  purples,  (p.  252 ;)  block  over  the  pattern  and  por- 
tions of  the  unprinted  part  the  paste  No.  39;  block  with  pad  roller  in  No.  53,(6  shade,)  dry 


CALICO  PRINTING. 


279 


and  raise  as  follows: — Wince  14  minutes  in  caustic  soda  at  2°  T.  at  110°  F.,  then  wince  in 
water  till  quite  bufi"  then  wince  in  4U0  gallons  water  with  1  quart  chloride  of  lime  at  12°  T. 
10  minutes;  wash  and  dry. 

Silk  Printing. 

Silk,  in  its  capacity  for  receiving  colors,  holds  a  medium  place  between  cotton  and  wool. 
From  its  being  an  animal  substance,  it  is  difficult  to  obtain  white  grounds  or  objects  after 
dyeing  mordanted  silk,  the  silk  itself  attracting  coloring  matter  somewhat  as  a  mordant. 
Previously  to  printing  silk,  it  is  well  scoured  by  boiling  for  2  hours  with  \  lb.  of  soap  to 
every  pound  of  silk,  then  well  washed  and  dried.  For  handkerchiefs,  black,  chocolate,  and 
red  mordants  are  printed,  aged,  and  dunged  off  same  as  for  cottons,  and  dyed  with  madder 
or  garancin,  soaped,  washed,  and  dried.  Purples  cannot  be  obtained  on  silk  by  mordanting 
and  dyeing  madder,  the  color  produced  being  a  mixture  of  red  and  purple.  All  sorts  of 
colors  can  be  produced  on  silk  by  steam,  the  whites  remaining  brilliant.  For  steam  colors, 
silk  is  mordanted  with  tin,  by  steeping  4  hours  in  a  solution  of  sulphomuriate  of  tin  at  2"  T., 
made  by  dissolving  1  lb.  of  muriate-of-tin  crystals  in  water,  and  adding  1  lb.  of  sulphuric 
acid  at  170'  T.,  and  reducing  to  2'  T.  After  steeping,  the  silk  is  washed  with  water,  and 
dried.     The  following  are  specimens  of  steam  colors  for  silk  : — 

Black. — 2  gallons  logwood  liquor  at  8°  T.,  1  quart  iron  hquor  at  10°  T.,  1  lb.  flour,  1  lb. 
light  British  gum ;  boil,  and  add  6  oz.  yellow  prussiate  of  potash ;  cool,  and  add  2  oz.  sul- 
phate of  copper,  1  pint  muriate  of  iron  at  80"  T.,  \  pint  pernitrate  of  iron  at  80°  T. 

Chocolate. — 2  gallons  of  sapan  liquor  at  12°  T.,  5  quarts  logwood  liquor  at  12°  T.,  1 
quart  bark  liquor  at  16°  T.,  2  lbs.  alum,  \h  lbs.  sal  ammoniac,  14  lbs.  gum-Senegal. 

Red. — 3  gallons  of  cochineal  liquor  at  4°  T.,  li  pints  bark  liquor  at  12°  T.,  3  lbs.  starch ; 
boil,  then  cool,  and  add  I  lb.  oxalic  acid,  1  lb.  muriate-of-tin  crystals. 

Yellow. — 3  gallons  of  bark  liquor  at  16°  T.,  8  oz.  aliun,  3  oz.  muriate-of-tin  crystals, 
3  oz.  oxalic  acid,  9  lbs.  gum-Senegal. 

Green. — 1  gallon  yellow,  -^  pint  extract  of  indigo,  2^  oz.  measure  of  muriate  of  tin 
at  120°  T. 

Blue. — 1  gallon  water,  1  lb.  yellow  prussiate  of  potash,  \  lb.  oxalic  acid,  ^  lb.  tartaric 
acid,  2  oz.  sulphuric  acid  at  170°  T.,  1  gallon  6  lbs.  gum-Senegal  water. 

Calico,  &c.,  printing  has,  since  the  repeal  of  the  duty,  risen  steadily  in  importance, 
till  it  is  now  one  of  the  most  influential  manufactures  of  Great  Britain.  From  a  table 
compiled  by  the  late  Mr.  Binyon,  and  communicated  by  Mr.  John  Graham,  there  were  in 
1840,  the  following  number  of  machines,  &c.,  in  use  : — 

List  of  Machines,  Tables,  (be,  employed  by  the  trade  in  England  aiid  America  in  1840. 


Cylinder  and 
Surface  Machines. 

Flat  Presses. 

Discharging 
Presses. 

Tables. 

Lancashire        .... 
Scotland            .... 

Ireland 

America 

435 
75 
18 

109 

2 

82 
1 

124 

8,275 

4,997 

'■  300 

884 

Since  that  period  there  are  no  data  as  to  the  number  of  printers  in  Great  Britain ; 
but  Mr.  John  Graham,  in  an  unpublished  "  History  of  the  Lancashire  Printers,"  gives  a 
table,  which  he  was  at  considerable  care  to  compile  from  perfectly  trustworthy  sources, 
showing  that  in  the  Lancashire  district,  which  includes  also  the  contiguous  counties,  there 
were,  in  1846,  128  firms,  employing— 

549  cylinder  machines. 
33  perrotines. 
7,187  block  tables. 

The  producing  power  of  the  Lancashire  district  having  thus  been  doubled  in  6  year.'. 

Several  printing  firms,  both  in  England  and  Scotland,  have  since  that  period  much 
enlarged  their  powers  of  production.  There  are  many  who  manufacture  liV'OO  pieces 
of  printed  cloth  per  week ;  and  there  are  four  concerns,  of  great  magnitude,  who.-e 
united  production  at  the  present  time  probably  does  not  fall  short  of  four  millions  of 
pieces  per  annum,  or  nearly  '/^  of  the  total  quantity  printed. 

The  following  estimate  of  the  exports  of  printed  goods  is  from  Mr.  Potter's  Lecture 
before  the  Society  of  Arts,  as  reporter  for  printed  fabrics  exhibited  in  the  Exhibition  of 
1851:— 

"In  reference  to  the  exports  of  printed  goods,  our  information  is  rather  obscure, 
owing  to  their  being  classed  with  dyed  goods  of  all  kinds."  "  After  considerable  thouglit 
and  calculation,  I  have  ventured  to  estimate  them  for  1851  at  15,544,000  pieces,  or  rather 


280                                           OATJCO  PRINTING. 

more  than  thrce-fourthg  of  our  entire  production.     These  goods  are,  however,  many  of 

them  of  the  cheap  and  more  staple  class  of  prints,  or  slight  goods  suited  to  warm  climates, 

and  for  markets  where  cheapness  is  the  great   recommendation.     In  value,  I  should  be 

disposed  to  estimate  our  export  of  printed  goods  at  £5,775,000. 

"In  reference  to  the  entire  export  of  manufactured  cotton  goods,  (exclusive  of  yarns,) 

it  maybe  assumed  that  out  of  £23,447,103,  given  as  the  export  of  1851,  about  one- 

fourth  may  be  placed  to  the  account  of  the  print  trade.     I  have  endeavored  to  estimate, 

from  the  Table  of  Exports  for  1851,  the  probable  quantity  of  loiopriced  prints  we  export, 

and  should  be  disposed  to  class  them  as  follows : — 

Pieces. 

"  Coast  of  Africa  and  the  Cape 300,000 

New  Zealand  and  South  Sea  Islands  -         -         -         -         36,000 

China,  Manilla,  and  Singapore 550,000 

British  West  Indies, 300,000 

Foreign  West  Indies 300,000 

St.  Thomas 200,000 

India 1,570,000 

Mauritius  and  Batavia 325,000 

Chili  and  Peru 800,000 

Brazil  and  East  Coast  of  South  America     -         -         -     1,000,000 

Egypt 84,000 

Turkey,  Ionian  Isles,  Greece,  and  Malta     -        -        -    1,000,000 

Total 6,465,000 

"  I  find  those  countries  which  take  our  lowest  description  of  goods,  and  where  the 

duties  are  chiefly  very  light — our  colonies,  India,  and  China,  receive  from  us  about  6i 

millions  of  pieces,  or  about  40  per  cent,  of  our  exports  in  printed  goods.     A  great  pro- 

portion of  the  finer  part  of  our  exports,  perhaps  three-fourths,  are  very  seriously  taxed, 

either  for  protection,  as  in  the  United  States,  the  Zollvcrein,  and  Belgium,  or  for  revenue, 

as  in  Brazil  and  the  other  South  American  markets.     A  part,  however,  of  these  better 

goods  find  their  way  into  consumption  in  Canada,  Turkey,  the  Ionian  Isles,  Egypt,  &c., 

subject  to  very  moderate  duties."     {Potter.) 

Exports  of  Calicoes  j)rinted  and  dyed  in  1857. 

Declared  real  value. 

Yards.                     £ 

Russia 1,513,080             42,913 

Sweden, 624,418             11,835 

Norway 787,269             15,235 

Hanover 1,954,664             49,814 

Ilanse  Towns 25,208,601           516,004 

Holland 12,899,706           254,199 

Belgium 903,764             22,600 

France 5,130,677             93,366 

Portugal,  Azores,  and  Madeira    -        -     18,956,056           297,178 

Spain  and  Canaries     ....       3,767,747             93,084 

Sardinia 11,003,456           167,807 

Tuscany 6,602,902           106,110 

Two  Sicilies 7,438,118           123,625 

Austrian  Territories    ....       7,191, '^73           101,663 

Greece 3,379,548             60,594 

Wallachia  and  Moldavia      -        -        -       1,180,001             19,779 

Syria  and  Palestine     ....     16,061,817           208,140 

Egypt 11,54.3,985            173,122 

West  Coast  of  Africa  (Foreign)  -         .     18,817,282           318,982 

Java 16,911,802           286,274 

Philippine  Isles 9,548,904           213,757 

China 12,030,344           203,443 

South  Sea  Islands        ....        1,552,337             29,995 

Cuba 14.144,771           249,760 

Porto  Rico 3,109,890             43,518 

Cura^oa 783,478             13,356 

St.  Thomas 20,529,211           290,956 

Haiti 5,191,059              96,936 

United  States 106,328,353        1,972,049 

Mexico 10,203,738           195,946 

CALICO  PRINTING.  281 

Exports  of  Calicoes  printed  and  dyed  in  1857.     (Continued.) 

Declared  real  value. 


Yards. 

Q 

Central  America 

. 

5,721,458 

86,007 

New  Granada 

. 

-      14,618,606 

229,310 

Venezuela 

. 

6,564,167 

107,417 

Brazil 

. 

-      84,304,760 

1,543,479 

Uraguay     - 

. 

8,749,894 

149,294 

Buenos  Ayres     - 

. 

-      17,870,263 

319,670 

Chili 

J 

-      21,536,565 

365,982 

Peru 

. 

-      23,426,258 

396,362 

Gibraltar    - 

. 

7,860,972 

125,567 

Malta 

. 

3,203,445 

46,912 

Ionian  Islands     - 

. 

3,790,985 

55,868 

West  Coast  of  Africa  (Britisb)    - 

7,286,177 

137,879 

South  AiVica  (Britis 

h)          -         - 

9,875,247 

196,859 

Mauritius    - 

7,556,558 

111,725 

British  East  Indies 

. 

-      89,717,000 

1,515,807 

Hong  Kong 

. 

2,621,464 

41,201 

Australia    - 

. 

-      15,769,817 

310,660 

British  North  America 

-      19,479,981 

331,106 

British  West  Indies 

and  B.  Guiana 

-     21,277,609 

293,710 

Honduras   - 

. 

4,090,657 

45,375 

Other  Countries 

.  . 

1,964,383 

36,007 

808,308,602  £13,921,428 
"  Tlie  home-consumption,"  says  Mr.  Potter,  "  I  estimate  at  4,500,000 ;  the  excise 
returns  for  1830,  gave  it  as  2,281,512  pieces.  The  repeal  of  the  duty,  and  the  decrease  in 
the  cost  of  production,  giving  the  consumer  goods  in  much  better  taste  and  value  at  one- 
half  the  price,  have  greatly  tended  to  this  increase."  "  The  immense  increase  of  produc- 
tion in  lower  goods  has  not  decreased  the  taste  in  the  higher  in  this  country,  tliough  it  may 
have  caused  it  to  make  less  apparent  progress  than  when  the  larger  part  of  the  supply  was 
of  fine  goods.  We  find  specimens  of  good  taste  on  the  lowest  material,  printed  at  the 
lowest  possible  price  for  export,  showing  a  taste  superior  to  that  in  use  for  our  best  work 
twenty  years  ago,  employing  greater  talent  in  design,  greater  skill  in  engraving, — the  cost 
of  production  cheap,  because  repaid  by  the  quantity  produced.  This  diffusion  of  art  and  of 
a  better  taste  cannot  be  otherwise  than  beneficial,  even  to  the  higher  class  of  productions, 
as  preparing  a  taste  and  demand  for  them  in  countries  where  high  price  would  never  have 
given  prints  any  admission.  Tlie  improvement  of  the  lower  cannot  militate  against  that  of 
the  higher,  either  in  the  moral,  intellectual,  or  artistic  world.  The  productions  of  the 
highest  class  of  French  goods  of  to-day,  whether  furniture  or  dresses,  are  superior  in  taste 
and  execution  to  those  of  any  former  period.  The  productions  of  the  first-class  printers  of 
Great  Britain  maintain  an  equal  advance,  and  are  superior  in  taste  and  execution,  in  every 
respect,  to  those  of  former  years.  Great  competition  and  rapidity  of  production  are  not 
immediately  beneficial  to  high  finish  and  execution  in  art ;  but  this  tendency  to  quickness 
of  production,  rather  than  perfection,  rectifies  itself;  and  machinery,  which  perhaps  at  first 
does  not  give  the  polish  that  excessive  labor  formerly  supplied,  ultimately  exceeds  it  by  its 
cheaper  and  more  regular  application.  It  is  remarkable  how  taste  or  novelty  in  that  class 
of  demand,  which  would  strike  the  casual  observer  as  the  one  fitted  for  its  greatest  develop- 
ment, is  limited  in  quantity.  The  limit  or  commencing  point  in  which  taste  or  novelty  enters 
freely  into  tlie  composition  of  a  print,  is  for  the  supply  of  the  working  and  middle  classes  of 
society.  They  require  it  quiet,  modest,  and  useful ;  and  any  deviation,  for  the  sake  of 
novelty,  which  calls  in  the  aid  of  the  brighter  and  less  permanent  color,  quickly  checks 
itself.  The  sober  careful  classes  of  society  cling  to  an  inoftensive  taste,  whicli  will  not  look 
obsolete  and  extravagant  after  the  lapse  of  such  a  time  .as  would  render  a  garment  compara- 
tively tasteless  and  unfashionable  in  a  higher  class.  This  trade  is,  to  the  printer,  most  ex- 
tensive and  valuable,  and  has  its  necessary  and  practical  bearing  on  his  taste ;  and  hence  it 
is  in  this  branch  of  the  business  the  English  printer  is  most  decidedly  superior  to  his  French 
competitors." 

It  would  appear  that  occasionally  attempts  were  made,  during  the  early  days  of  printing, 
to  produce  work  possessing  a  high  degree  of  artistic  excellence  ;  and  as  the  specimens  that 
have  been  preserved  to  our  time  are  very  rare,  it  is  fair  to  conclude  that  these  experiments 
were  not  successful  in  a  pecuniary  point  of  view.  In  the  museum  of  the  Peel  Park,  at  Sal- 
ford,  there  is  a  curious  and  interesting  piece  of  printed  linen,  bearing  the  date  1701,  (at  this 
period  cloth  of  all  cotton  was  prohibited,)  and  which  nuist  have  been  printed  from  copper 
plates  of  very  unusual  size.  Apparently,  the  pattern  has  been  produced  by  two  plates,  each 
about  4  feet  6  inches  by  3  feet.    The  design  is  printed  in  madder  red,  and  is  thus  described 


285 


CALOMEL. 


by  Mr.  Plant,  the  curator  of  the  museum  :  "  The  printed  piece  of  linen  measures,  in  the 
full  length  of  the  design,  6  feet  10  inches,  bv  3  feet  2  inches  in  breadth.  The  composition 
in  the  design  is  very  bold  and  free — in  my  opinion  indicating  very  strongly  the  feehngs  of 
an  artist  who  had  been  educated  in  the  Flemish  school.  The  grouping  of  the  trees,  figures, 
cattle,  and  fowls  is  probably  a  direct  copy  from  an  engraving  or  sketch  by  Berghem,  whose 
paintings  and  engravings  of  such  subjects  are  well  known  for  their  truth  to  nature.  His 
works  bear  date  1638  to  1680.  Perhaps,  to  fill  up  the  design,  and  form  a  picturesque  com- 
position, the  artist  has  borrowed  from  the  French  painters  the  classic  ruins  which  form  the 
sides  of  the  design  ;  it  has  had  the  effect  of  producing  an  anachronism.  The  upper  group 
represents  a  peasant  seated  upon  the  waif  of  a  well,  blowing  a  flute ;  near  him  stands  a 
woman  with  a  distaff;  a  group  of  sheep,  cow,  and  a  dog,  in  the  foreground.  The  back- 
ground shows  a  landscape,  and  on  each  side  this  group  are  ruins,  columns,  and  trees,  re- 
flected in  the  stream  below.  On  a  broken  bank,  midway  between  the  two  groups,  are  two 
dogs  chasing  a  stag.  The  lower  group,  although  there  is  no  defined  line  of  separation 
between  the  groups,  represents  a  peacock,  fowls,  and  chickens,  upon  a  bank  and  ruins ; 
landscape  and  river  scenery  beyond.  Over,  a  hawk  carrying  a  chicken,  the  sides  occupied 
with  a  ruined  portico,  tomb,  and  pedestal  and  vase,  trees,  and  broken  ground  ;  and  below 
are  ducks  swimming,  and  water-plants  on  the  bank.  At  the  bottom  of  the  piece  are  those 
parts  of  the  pattern  which  would  print  or  fit  on  the  top  part  of  the  design.  On  the  stone- 
work of  the  well,  in  the  upper  group,  is  printed,  '  R.  JONES,  1761  ; '  on  the  broken  stone- 
work, in  the  centre  of  the  lower  group,  is  printed,  '  R.  I.  and  Co.,  OLD  FORD,  1761.'"  Old 
Ford  is  situated  at  Bow,  where  the  East  London  Water  Works  now  are,  and  where  there 
was  a  print  work  at  the  time  specified.  This  design  was  no  doubt  printed  for  furniture 
hangings  or  tapestry,  for  which  it  is  exceedingly  well  adapted,  the  work  being  altogether 
a  remarkable  production  for  the  period. 

CALOMEL.  Professor  WiJhler  proposes  to  prepare  calomel  in  the  humid  way  by  de- 
composing a  solution  of  corrosive  sublimate  by  sulphuric  acid.  The  commercial  salt  is 
dissolved  in  water  at  122°  to  saturation.  Sulphurous  acid  gas,  evolved  by  healing  coarse 
charcoal  powder  with  concentrated  sulphuric  acid,  is  passed  into  the  hot  solution :  the 
separation  of  the  calomel  commences  immediately.  When  tlie  solution  is  saturated  with  the 
gas,  it  is  digested  for  some  time,  then  left  to  get  cold,  and  filtered  from  the  calomel,  which 
is  afterwards  washed.  The  filtrate  usually  contains  some  unchangeable  corrosive  sublimate, 
which  may  be  converted  into  calomel,  either  by  heating  to  boiling,  or  by  a  fresh  introduc- 
tion of  sulphurous  acid  and  heating.  Calomel  obtained  in  this  manner  is  a  crystalline  pow- 
der of  dazzling  whiteness,  glittering  in  the  sunlight. 

The  presence  of  corrosive  sublimate  in  calomel  is  easily  detected  by  digesting  alcohol 
upon  it,  and  testing  the  decanted  alcohol  with  a  drop  of  caustic  potash,  when  the  character- 
istic brick-colored  precipitate  will  fall,  if  any  of  that  salt  be  present.  To  detect  subnitrate 
of  mercury  in  calomel,  digest  dilute  nitric  acid  on  it,  and  test  the  acid  with  potash,  when  a 
precipitate  will  fall  in  case  of  that  contamination.  As  it  is  a  medicine  so  extensively 
administered  to  children  at  a  very  tender  age,  its  purity  ought  to  be  scrupulously  watched. 
117-75  parts  of  calomel  contain  100  of  quicksilver.  H.  M.  N. 
CAMBOGIA.     See  Gamboge. 

CAMEO.  {Cajnec,  Fr.  ;  Cammeo,  It.)  Correctly  a  precious  stone  engraved  in  relief, 
as  opposed  to  an  intaglio,  which  is  cut  into  Ihe  stone.  The  earliest  cameos  appear  to  have 
been  cut  upon  the  onyx,  and,  subsequently,  on  the  agate.  The  true  cameo  is  formed  upon 
a  stone  having  two  or  more  layers,  differing  in  color ;  and  the  art  of  the  cameo  engraver 
consists  in  so  cutting  as  to  appropriate  those  differently  colored  layers  to  distinct  parts  or 
elevations  of  the  work. 

Many  of  the  varieties  of  calcedony  present  in  section  transparent  and  opaque  layers ; 
and  beautiful  works  have  been  cut  upon  such  specimens  of  this  material.  The  calcedony 
and  agate  are,  however,  not  unfrequently  colored  artificially.  The  layers  vary  very  much 
in  their  structure,  some  being  absorbent  and  others  not  so.  Such  stones  are  taken,  and  if 
it  is  desired  to  have  black  and  white  layers,  they  are  boiled  ii^  a  solution  of  sugar  or  honey, 
and  then  in  sulphuric  acid.  The  sugar  or  honey  is,  in  the  first  place,  absorbed  by  the  more 
porous  layers,  and  then  decomposed  by  the  acid.  Red  or  brownish-red  layers  are  produced, 
by  occasioning  the  stone  to  absorb  a  solution  of  sulphate  of  iron,  and  then,  by  exposure  to 
heat,  effecting  the  oxidation  of  the  metal.  This  being  done,  layers  very  strongly  contrasted 
in  color  are  tlie  result,  and  very  fine  cameos  have  been  cut  upon  stones  so  prepared.  In 
Italy  and  in  France,  the  art  of  producing  the  cameo  dur  has  been,  to  some  extent,  revived ; 
but  the  immense  labor  which  such  hard  materials  require,  renders  them  so  expensive,  that 
these  cameos  have  not  come  into  general  use. 

Porcelain  and  glass  have  been  employed  as  substitutes  for  the  natural  stones,  but  the 
results  were  so  inferior,  that  these  materials  have  of  late  been  entirely  neglected  for  this 
purpose. 

The  shells  of  several  molluscous  animals  are  now  commonly  used.  Many  of  these  shells 
afford  the  necessary  variety  of  color,  are  soft  enough  to  be  worked  with  faciUty,  yet  hard 
Dnough  to  wear  for  a  considerable  time  without  injury. 


CAMPHENE.  2S3 

The  natural  history  of  the  mollusca  producing  the  shells,  and  the  best  account  of  the 
manufacture  of  cameos,  was  given  by  /.  E.  Gnnj,  of  the  British  Museum,  in  a  paper  read 
before  the  Society  of  Arts  in  18-17,  to  which,  and  to  his  paper  in  the  Philosophical  Transac- 
tions, we  are  indebted  for  much  of  the  information  contained  in  this  article. 

It  was  the  custom  in  Holland  to  use  the  pearly  nautilus  as  a  cameo  shell,  and  several 
kinds  of  turbines  or  wreath  shells,  which  have  an  opaque  white  external  coat  over  an  inter- 
nal pearly  one.  These  are  now  rarely  employed.  The  shells  now  used  are  those  of  the 
flesh-eating  univalve,  {Ga>iteropoda  ptenobranchiata  zoophar/a,)  which  are  peculiar  for  being 
all  formed  of  three  layers  of  calcareous  matter,  each  layer  being  composed  of  three  perpen- 
dicular laminoe  placed  side  by  side  ;  the  laminae  comprising  the  central  layer,  being  placed 
at  right  angles  with  one  of  the  inner  and  outer  ones ;  the  inner  and  outer  being  placed 
longitudinally  with  regard  to  the  axis  of  the  line  of  the  shells,  while  the  inner  laminas  are 
placed  across  the  axis,  and  concentrically  with  the  edge  of  the  mouth  of  the  cone  of  the 
shell.     {Gray,  Phil.  Trans.) 

This  structure  furnishes  the  cameo  cutter  with  the  means  of  giving  a  particular  surface 
to  his  work,  a  good  workman  always  putting  his  work  on  the  shell  in  such  a  manner,  that 
the  direction  of  the  laminas  of  the  central  coat  is  longitudinal  to  the  axis  of  his  figure. 
The  central  layer  forms  the  body  of  the  bas-relief,  the  inner  lamina  being  the  ground,  and 
the  outer  one,  the  third  or  superficial  color,  which  is  sometimes  used  to  give  a  varied  ap- 
pearance to  the  surface  of  the  figure.  The  cameo  cutter,  therefore,  selects  for  his  purpose 
those  shells  which  have  thi-ee  layers  of  different  colors,  as  these  afford  him  the  means  of 
relieving  his  work ;  and  secondly,  those  which  have  the  three  layers  strongly  adherent  to- 
gether, for,  if  they  separated,  his  labor  would  be  lost. 

The  following  are  the  kinds  of  shells  now  employed:  1.  The  bull's  mouth,  (Cassis 
riifum,)  which  has  a  red  inner  coat,  or  what  is  called  a  sardonyx  ground.  2.  The  black 
helmet,  [Cassis  Madagascariensis,)  which  has  a  blackish  inner  coat,  or  what  is  called  an 
onyx  ground.  3.  The  horned  helmet,  [Cassis  cormitum,)  wuth  a  yellow  ground.  4.  The 
queen's  conch,  [Strombus  gigas,)  with  a  pink  ground. 

The  bull's  mouth  and  the  black  helmet  are  the  best  shells.  The  horned  helmet  is  apt  to 
eeparate  from  the  ground,  or  double,  and  the  last,  the  queen's  conch,  has  but  seldom  the 
two  colors  marked  with  sulHcieut  distinctness,  and  the  finish  of  the  ground  color  flies  on 
exposure  to  light. 

The  red  color  of  the  bull's  mouth  extends  only  a  slight  distance  into  the  mouth  of  the 
shell,  becoming  paler  as  it  proceeds  backwards.  The  dark  color  extends  further  in  the 
black  and  yellow  varieties.  Hence,  the  bull's  mouth  only  affords  a  single  cameo  large 
enough  to  make  brooches  of,  and  several  small  pieces  for  shirt-studs.  The  black  hel- 
met yields  on  an  average  about  five  brooches,  and  several  pieces  for  studs,  while  the 
queen's  conch  affords  only  one  good  piece. 

Forty  years  since,  very  few  cameos  were  made  from  any  shells  but  the  black  helmet, 
and  the  number  of  sliells  then  used  amounted  to  about  300  annually,  nearly  all  of  which 
were  sent  from  England,  being  all  that  were  then  imported.  The  black  helmet  is  imported 
into  England  from  Jamaica,  Nassau,  and  New  Providence.  They  are  not  found  in  Mada- 
gascar, though  naturalists  have  for  a  long  period  called  them  il/ac^ai^asear  helmets.  [Gray.) 

Of  the  bull's  mouth,  half  are  received  direct  from  the  Island  of  Bourbon,  to  which 
place  they  are  brought  from  Madagascar,  and  the  other  half  are  obtained  from  the  Island 
of  Ceylon,  being  received  by  the  way  of  Calcutta ;  hence  they  are  often  called  "  Calcutta 
shells." 

So  rapidly  has  the  trade  in  those  shells  increased,  that  Mr.  Gray  informs  us,  that  in 
Paris  100,500  shells  are  used  for  cameos  annually.     These  are  divided  as  follows: 

Price.  Value. 

Bull's  mouth  -         -        -     80,000         -    -         Is.     8c/.  -  -  £6,400 

Black  helmet                    -       8,000         -     -         5        0  -  -  1,920 

Horned  helmet       -         -          500         -     -         2        6  -  -  60 

Queen's  conch        -        -     12,000        -    -        1       2^  -  -  725 


Sterling  £9,105 

The  manufacture  of  shell  cameos  was  for  some  time  confined  to  Italy ;  about  twenty 
years  since,  an  Italian  commenced  making  them  in  Paris,  and  now  the  trade  is  confined 
principally  to  the  l^-ench  capital,  where  not  less  than  300  persons  are  engaged  in  the  manu- 
facture. 

Nearly  all  the  cameos  made  in  France  arc  sent  to  England.  In  Birmingham,  many  of 
them  are  mounted  as  brooches,  and  exported  to  America  and  the  British  colonies. 

In  1856  we  imported,  of  shell  cameos  not  set,  to  the  value  of  £6,683. 

CAMPHENE.  Rectified  oil  of  turpentine  is  sold  in  the  shops  under  this  name  for 
burning  in  lamps.  Crude  oil  of  turpentine  is  redistilled  with  potash,  and  then  with  water, 
and  lastly,  to  secure  its  perfect  purity,  with  chloride  of  calcium.     The  oil  thus  prepared 


284  CAMPHOLE. 

forms  a  limpid,  colorless  liquid;  its  specific  gravity  is  about  O-STO,  but  it  is  subject  to  some 
sliuht  variations;  C^H*  appears  foiily  to  represent  this  and  several  other  similar  oils.  It  is 
very  intiammable,  burning  with  a  bright  white  flame,  and  without  a  proper  supply  of  air  it 
evolves  much  dense  smoke,  hence  peculiar  lamps  (Camphene  lamps)  are  required.  Where 
it  has,  from  exposure  to  air,  absorbed  oxygen,  and  become  reainijied,  it  is  unfit  for  pur- 
poses of  illumination.  Such  camphene  very  rapidly  clogs  the  wick  with  a  dense  carbon, 
and  is  liable  to  the  thick  black  smoke,  which  is  so  objectionable  iu  the  camphene  lamps  if 
tliey  are  not  properly  attended  to. 

To  purify  old  camphene,  it  must  be  redistilled  from  caibonate  of  potash,  or  some  simi- 
laily  active  substance  to  deprive  it  of  its  resin.     See  Lamps. 

CAMPHOLE.  One  of  the  oils  obtained  from  coal  tar.  Mansfield  gives  this  name  to 
the  oils  cinnole  and  c>pno!e,  which  boil  at  284°  and  338°  Fahrenheit,  when  collected  to- 
gether. The  specific  gravity  of  crude  camphole  ranges  from  '88  to  "OS,  and  the  less  vola- 
tile portions  frequently  contain  naphthaline,  which  raises  their  specific  gravity.  This  sub- 
stance, either  alone  or  mixed  with  pyroxylic  spirit,  is  applicable  for  burning  in  lamps  or  for 
dissolving  rosins,  as  a  substitute  for  oil  of  turpentine. 

CAMPHOR.     There  are  two  kinds  of  camphor  imported : — 

.I.M'AN  Camphor,  called  Dutch  Camphor,  because  it  is  always  brought  by  the  Dutch  to 
England.  It  comes  by  the  way  of  Batavia,  and  is  impoi-ted  in  tubs  (hence  it  is  called  tub 
camphor)  covered  with  matting,  and  each  surrounded  by  a  second  tub,  secured  on  the  out- 
side by  hoops  of  twisted  cane. 

China  Camphor,  or  Formosa  Camphor,  is  imported  from  Singapore  and  Bombay  iu 
chests  lined  with  lead-foil  containing  about  li  cwts. 

It  has  been  suggested  to  introduce  the  camphor  trees  into  other  countries.  South 
Georgia  and  Florida  are  named  as  suitable  localities. 

The  Laura  campjhora  is  commonly  found  in  all  the  nurseries  around  Paris,  and  sold  at  5 
francs  for  a  plant  30  inches  high.  At  full  growth  the  tree  attains  an  altitude  of  from  40 
to  oO  feet. 

The  wood  of  the  camphor  tree  is  in  favor  for  carpenter's  work  ;  it  is  light,  easily  worked, 
duraljle,  and  not  lial)le  to  be  attacked  by  insects. 

It  is  said  that  in  Sumatra  numbers  of  trees  are  cut  down  before  one  is  found  to  repay. 
Not  a  tenth  part  of  the  trees  attacked  yield  either  camphor  or  camphor  oil. 

The  camphor  is  distinguished  by  the  names  of  head,  belly,  and  foot,  when  in  bulk.  The 
head  camphor  is  in  large  white  flakes ;  the  belly  camphor,  small  brown  flakes,  transparent, 
like  resin  coarsely  powdered;  the  foot,  like  dark-colored  resin.  A  native  "catty"  may  be 
divided  into: — 

1.  Capello,  or  large  head =  2'2 

2.  Capello  cachcll,  or  small  head  -         -         -         -         =   3'o 

3.  Baddan,  or  belly =4-2 

4.  Cakee,  or  foot         ...-...=  6'1 

=   1  Catty 16 

The  inquiries  of  Royle  and  Roxburgh  agree  with  the  records  of  Sir  G.  Staunton,  Dr. 
Abel,  and  Mr.  C.  Grove,  of  the  estimation  phiced  ujjon  the  camphor  of  Borneo  by  the  Chi- 
nese, who  actually  give  a  greater  price  for  the  coarser  article  than  they  afterwards  sell  it 
for,  when  in  a  purified  state  for  commerce.  Hence  it  is  inferred  that  the  Borneo  camphor, 
being  so  strong,  communicates  its  odor  and  virtues  to  other  matters,  and  thus  an  adulter- 
ated drug  is  gold  by  the  Chinese  ;  or  it  may  bo  mixed  with  the  camphor  obtained  by  cutting 
and  macerating  the  wood  of  the  Laura  camphora,  that  grows  in  China.  Sir  G.  Staunton, 
however,  declares  the  Chinese  sell  the  camphor  at  a  lower  price  than  they  give  for  it  at 
Borneo. 

Our  importations  in  18uG  were: — 

Camphor,  unrefined 4,505  cwts. 

"         refined G26     " 

CAMPHOR,  ARTIFICIAL.  When  hydrochloric  "acid  (muriatic)  is  passed  into  oil  of 
turpentine,  surrounded  by  ice,  two  compounds  are  obtained,  one  solid,  and  the  other  fluid. 
The  first,  solid  artificial  camphor,  C^^IP^HCl,  is  white,  transparent,  lighter  than  water,  and 
has  a  camphoraceous  taste.     The  fluid  is  termed  liquid  artificial  camphor,  or  terelnne. 

CAilPHOR,  OIL  OF  LAUREL.  When  the  branches  of  Camphora  ojficinarum  are 
distilled  with  water,  a  mixture  of  camphor  and  a  liiiuid  essential  oil  is  obtained.  This  is 
the  oil  of  camphor;  it  has  a  density  of  O'.UO,  and  its  composition  is  C'lI'^O.  By  ex- 
posure to  oxvgon  gas,  or  to  the  action  of  nitric  acid,  it  absorbs  oxygen,  and  becomes  solid 
camphor,  C^IP^O^ 

This  is  an  esteemed  article  in  the  eastera  market ;  it  undergoes  no  preparation,  and 
though  named  oil,  it  is  rather  a  liquid  and  volatile  resin.     The  natives  of  Sumatra  make 


CANDLES.  285 

a  transverse  incision  in  the  tree  to  the  depth  of  some  inches,  the  cut  sloping  downwards, 
so  as  to  form  a  cavity  of  the  capacity  of  a  quart ;  a  Hghted  reed  is  placed  in  it  for  about 
10  minutes,  and  iu  the  space  of  a  night  the  cavity  is  tilled  with  this  fluid.  The  natives 
consider  this  oil  of  great  use  as  a  domestic  remedy  for  strains,  swellings,  and  inflamma- 
tions. 

Dr.  Royle  states  the  trees  are  of  largo  dimensions,  from  2i  to  7  feet  in  diameter.  The 
same  tree  that  produces  the  oil,  would  have  produced  the  camphor  if  unmolested,  the  oil 
being  supposed  to  be  the  Urst  stage  of  the  camphor's  forming,  and  is  consequently  found  iu 
younger  trees. 

CAMPHOR  STORM  GLASSES.  Glasses  called  usually  storm  glasses,  and  sold  as  indi- 
cators of  atmospheric  changes. 

"  Storm  glasses"  are  made  by  dissolving  : — 

Camphor       ..--.-..2i  drachms 
Nitre     ---------38  grains 

Sal  ammoniac        -------38  grains 

Water  --- -9  fluid  drachms 

Rectified  spirit  of  wine-         -----     11  fluid  drachms. 

Plumose  crystals  form  in  the  glass,  and  are  said  to  condense  and  collect  at  the  bottom 
of  the  bottle  on  the  approach  of  a  storm,  aad  to  rise  up  and  diti'use  themselves  through  the 
liquid  on  the  approach  of  fine  weather ;  but  Dr.  Parrion  thinks  that  their  weather-predict- 
ing qualities  are  false,  and  that  light  is  the  agent  which,  together  with  temperature,  iuflu- 
encl&s  the  condition. 

CAM-WOOD.  An  African  dye-wood,  shipped  principally  from  Sierra  Leone  in  short 
logs.  Mr.  G.  Loddiges,  in  his  botanical  cabinet,  figures  the  plant,  producing  it  under  the 
name  of  Baphia  nitida ;  it  is  a  leguminous  plant,  and  has  been  introduced  into,  and  has 
flowered  in,  this  country. 

CANADIAN  BALSAM.  A  product  of  the  Abies  balsamea,  or  balm  of  Gilead  fir.  The 
finer  varieties  of  this  balsam  are  used  for  mounting  objects  for  the  microscope.  See 
Balsams.  • 

CANARY  WOOD.  A  wood  is  imported  into  this  country  under  the  name  of  Madeira 
mahogany,  which  appears  to  be  this  canary  wood.  It  is  the  produce  of  the  Royal  Bay, 
Laurus  indica,  a  native  of  the  Canary  Islands.  It  is  rather  a  light  wood,  and  of  a  yellow 
color. 

CANDLES.  In  a  lecture  delivered  at  the  Society  of  Arts  by  Mr.  Wilson,  and  published 
in  their  journal,  he  described  the  progress  of  the  more  recent  improvements.  In  this  he 
says  :  "  Candles,  beautiful  in  appearance,  were  made  by  distilling  the  cocoa-nut  acids ;  but, 
on  putting  them  out,  they  gave  off  a  choking  vapor,  which  produced  violent  coughing." 
This  prevented  those  candles  from  being  brought  into  the  market.  "  By  distilling  cocoa- 
nut  lime  soap,  we  made  beautiful  candles,  resembling  those  made  from  paraffine,  burning 
perfectly  ;  but  the  loss  of  material  in  the  process  was  so  great,  that  the  subsequent  improve- 
ments superseded  its  use.  Under  one  part  of  this  patent,  the  distillation  was  earned  on 
sometimes  with  the  air  partially  excluded  from  the  apparatus,  by  means  of  the  vapor  of 
water,  sometimes  without,  the  low  evaporating  point  of  the  cocoa-nut  acids  rendering  the 
exclusion  of  air  a  matter  of  much  less  importance  than  when  distilling  other  fat  acids."  At 
this  time,  in  conjunction  with  Mr.  Jones,  Mr.  Wilson  appears  to  have  first  tried  using  the 
vapor  of  water  to  exclude  the  air  from  the  apparatus  during  distillation.  This  led,  in  1842, 
E.  Price  and  Co.  to  patent,  in  the  names  of  Wilson  and  Jones,  which  involved  the  treat- 
ment of  fats,  previously  to  distillation,  with  sulphuric  acid,  or  nitrous  gases.  M.  Fremy,  in 
his  valuable  paper  in  the  "  Annales  do  Chimie,"  describes  treating  oils  with  half  their  weight 
of  concentrated  sulphuric  acid,  by  which  their  melting  point  was  greatly  raised.  Ho  gave, 
however,  particular  directions  that  tlie  matter  under  process  siiould  be  "kept  cool.  Instcail 
of  doing  this,  Mr.  Wilson  found  it  advantageous  to  expose  the  mixture  of  fat  acid  and  fat  to 
a  high  temperature,  and  this  is  still  done  at  Price's  works. 

"  Our  process  of  sulphuric  acid  saponification  was  as  follows  : — Six  tons  of  the  material 
employed — usually  palm  oil,  though  occasionally  we  work  cheap  animal  fat,  vegetable  oils, 
and  butter,  and  Japan  wax — were  exposed  to  the  combined  action  of  6.f  cwts.  of  concen- 
trated sulphuric  acid,  at  a  temperature  of  .350 '  F.  In  this  process  tlie  glycerine  is  decom- 
posed, large  volumes  of  suli)hurous  acid  are  given  off,  and  the  fat  is  changed  into  a  mixture 
of  fat  acids,  with  a  very  high  melting  jioint.  This  is  Wiishcd,  to  free  it  from  charred  matter 
and  adhering  sulphuric  acid,  and  is  then  transferred  into  a  still,  from  which  the  air  is  ex- 
cluded by  means  of  steam.  The  steam  used  by  us  is  heated  in  a  series  of  pipes  similar  to 
those  used  in  the  hot-blast  apparatus  in  the  manufacture  of  iron,  the  object  of  heating  the 
steam  being  only  to  save  the  still,  and  reduce  to  a  small  extent  gaseous  loss  in  distillation." 
"  We  still,"  says  the  patentee,  "  employ  this  process,  and  in  some  Ciises  reduce  the  quantity 
of  acid  employed  to  4  lbs.  and  even  3  lbs.  to  a  cwt.  of  the  fat." 

In  185-1:,  Mr.  Tighlman  obtained  a  patent  for  the  exposure  of  fats  and  oils  to  the  action 


286  CANDLES. 

of  water  at  a  high  temperature,  and  under  great  pressure,  in  order  to  cause  the  combination 
of  the  water  with  the  elements  of  the  neutral  fats  ;  so  as  to  produce  at  the  same  time  free 
fat  acid  and  solution  of  glycerine.     See  Glycerine. 

He  proposed  to  effect  this  by  pumping  a  mixture  of  fat  and  water,  by  means  of  a  force- 
punip,  through  a  coil  of  pipe  heated  to  about  612°  F.,  kept  under  a  pressure  of  about  2,000 
lbs.  to  the  square  inch  ;  and  he  states  that  the  vessel  must  be  closed,  so  that  the  requisite 
amount  of  pressure  may  be  applied  to  prevent  the  conversion  of  water  into  steam.  Mr. 
Wilson  improved  upon  this  process,  by  passing  steam  into  fat  at  a  high  temperature  ;  and 
by  this  process  hundreds  of  tons  of  palm  oil  are  now  treated.  The  glycerine  and  fat  distil 
over  together,  but  no  longer  combined  ;  and  the  former,  being  separated,  is  subjected  to  a 
redistillation,  by  which  it  is  purified.  This  distillation  is  effected  by  transmitting  through 
the  fat  contained  in  an  iron  still,  steam  at  about  6U0°  or  '/OO"  F.,  heated  by  passing  through 
iron  pipes  laid  in  a  fire.  The  steam  is  transmitted  till  the  oily  matter  is  heated  to  about 
350' ;  the  vapors  produced  being  carried  into  a  high  shaft  by  a  pipe  from  the  cover  of  the 
iron  vessel.  The  hot  oily  matter  is  then  run  into  another  vessel  made  of  brick  lined  with 
lead,  and  sunk  in  the  ground,  for  the  purpose  of  supporting  the  biiek  work  under  or  against 
the  internal  pressure  of  the  fluid.  It  has  a  wooden  cover  lined  with  lead,  directly  beneath 
which,  and  extending  across  the  vessel,  is  a  leaden  pipe,  1  inch  in  diameter,  having  a  small 
hole  in  each  side,  at  every  6  inches  of  its  length ;  and  through  this  pipe  is  introduced  a 
mi.xture  of  1,000  lbs.  of  sulphuric  acid,  sp.  gr.  1-8,  and  the  same  weight  of  water.  The  in- 
troduction of  the  mixture,  which  falls  in  divided  jets  into  the  heated  fat,  produces  violent 
ebullition  ;  and  by  this  means  the  acid  and  fat  are  perfectly  incorporated  before  the  action 
of  the  acid  becomes  apparent  by  any  considerable  discoloration  of  the  fat.  As  the  ebullition 
ceases,  the  fat  gradually  blackens ;  and  the  matter  is  allowed  to  remain  for  6  hours  after  the 
violent  ebullition  has  ceased.  The  offensive  fumes  produced  are  caia-ied  off  by  a  large  pipe, 
which  rises  from  the  top  of  the  vessel,  then  descends,  and  afterwards  rises  again  into  a  high 
chimney.  At  the  downward  part  of  this  pipe  a  small  jet  of  water  is  kept  playing,  lo  con- 
dense such  parts  of  the  vapors  as  are  condensable.  At  the  end  of  the  6  hours  above  men- 
tioned, the  operation  is  complete,  and  the  product  is  then  pumped  into  another  close  vessel 
and  wa.shed,  by  being  boiled  up  (by  means  of  free  st«am)  with  half  its  bulk  of  water.  The 
water  is  drained  off,  and  the  washing  repeated,  except  that  in  the  second  washing  the  water 
is  acidulated  with  100  lbs.  of  sulphuric  acid.  The  ultimate  product  is  allowed  to  settle  for 
24  hours ;  after  which  it  is  distilled  in  an  atmosphere  of  steam — once,  or  oftener, — until 
well  purified,  and  the  product  of  distillation  is  again  washed,  and  after  being  pressed  in  the 
solid  state,  is  applied  to  the  manufacture  of  candles. 

The  following  definitions  of  terms  applied  to  candles  are  by  Mr.  "Wilson : — 

Belmont  Sperm. — Made  of  hot  pressed,  distilled  palm  acid. 

Belmont  Wax. — The  same  material  tinged  with  gamboge. 

Best  Composite  Candles. — Made  of  a  mixture  of  the  hard  palm  acid,  and  stearine  of 
cocoa-nut  oil. 

Composites,  Nos.  1,  2,  and  3,  are  made  of  palm  acids,  and  palm  acids  and  cocoa-nut 
stearine,  the  relative  proportions  varying  according  to  the  relative  market  prices  of  palm  oil 
and  cocoa-nut  oil  at  the  particular  time  when  the  candles  are  manufactured. 

Composite,  No.  4.  A  description  of  candle  introduced  at  a  price  a  very  little  above 
the  price  of  tallow  dip  candles.     They  are  somewhat  dark  in  color,  but  give  a  good  light. 

The  highest-priced  candles  are  usually  made  in  the  ordinary  mould  ;  but  at  Price  and 
Co.'s  manufactory  they  have  a  machine  for  moulding  the  ordinary  stearine  candles,  and 
others  of  a  similar  nature.  When  one  set  of  candles  is  discharged  from  the  moulds,  the 
moulds  are  re-wicked  for  the  next  process  of  filling.  These  moulds  are  arranged,  side  by 
side,  eighteen  in  number,  on  a  frame  ;  and  for  each  mould  there  is  a  reel  capable  of  holding 
sixty  yards  of  wick,  enclosed  in  a  box.  The  moulded  candle,  being  still  attached  to  the 
cotton  wick,  when  it  is  forced  out  of  the  mould,  brings  the  fresh  wick  into  it.  The  moulded 
candles  are,  by  a  very  ingenious  contrivance,  held  firm  in  a  horizontal  position  while  a  knife 
passes  across  and  severs  the  wick.  The  wicks  for  the  new  set  of  candles  are  secured,  by 
forceps,  firmly  to  the  conical  caps  of  the  moulds  ;  these  are  carried  into  a  vertical  position, 
and  slid  upon  a  railway  to  a  hot  closet,  where  they  become  sufficiently  warm  to  receive  the 
fit,  which,  kept  at  the  melting  point  by  steam  pipes,  is  held  in  a  cistern  above  the  rails ; 
from  this  cistern  the  moulds  are  filled  by  as  many  cocks,  which  are  turned  by  one  impulse. 
If  we  imagine  an  extensive  series  of  these  sets  of  moulds  travelling  from  the  machine  over 
a  railway,  in  regular  order,  and  that,  when  the  fat  luis  become  solid,  these  return,  the  can- 
dles are  discharged,  and  the  process  is  renewed, — the  machine  will  be  tolerably  well  under- 
stood. Each  machine  holds  about  2<)0  frames  of  moulds,  and  each  contains  18  bobbins, 
starting  each  with  60  yards  of  cotton  wick. 

K/i//it-Lig/ifs. — These  are  short  thick  cylinders  of  fat,  with  a  very  thin  wick,  so  propor- 
tioned one  to  the  other,  that  they  burn  any  required  number  of  hours.  The  moulds  in 
which  these  are  made  are  metal  frames,  perforated  with  a  number  of  cylindrical  holes,  and 
having  a  movable  bottom,  with  a  thin  wire  projecting  from  it  into  every  mould.     These  arc 


CAOUTCHOUC.  287 

filled  with  melted  fat,  and,  when  cold,  the  bottoms  are  forced  up,  and  all  the  cylinders  of  fat 
ejected,  each  having  a  small  hole  through  which  the  wick,  a  cotton  previously  impregnated 
with  wax,  is  inserted.  This  being  done,  the  night-light,  being  pressed  on  a  warm  porcelain 
slab,  is  melted  sufficiently  to  cement  the  wick.  These  night-lights  are  burned  in  glass 
cylinders,  into  which  they  fit. 

Child's  Night-Lights  are  melted  fat  poured  into  card-board  boxes,  which  have  a  hole  iu 
the  bottom,  through  which  the  wick  and  its  metallic  support  are  placed. 

CANES.  Canes  of  various  kinds  are  employed  in  manufactures,  as  the  Sugar  cane, 
Bamboo  canes,  and  Rattan  canes,  &c.  The  bamboo  is  a  plant  of  the  reed  kind,  growing  in 
the  Ea.st  Indies,  and  other  warm  climates,  and  sometimes  attaining  the  height  of  60  feet. 
Old  stalks  grow  to  five  or  six  inches  diameter,  and  are  so  hard  and  durable  as  to  be  used  for 
building,  and  for  all  sorts  of  furniture,  for  water-pipes,  and  for  poles  to  sujiport  palanquins. 
The  smaller  kinds  are  used  for  walking-sticlcs,  flutes,  &c. 

In  1856,  we  imported  309,000  Bamboo  canes  into  England. 

Rattan  canes  are  often  confounded  with  the  Bamboo.  They  are,  however,  the  produce 
of  various  species  of  the  genus  Calamus.  They  are  cylindrical,  jointed,  very  tough  and 
strong,  from  the  size  of  a  goosequill  to  that  of  the  human  wrist,  and  from  fifty  to  a  hundred 
feet  in  length.     They  are  used  for  wicker-work,  seats  of  chairs,  walking-sticks,  &c. 

In  1856,  we  imported  of  Rattan  canes,  7,840,702,  the  computed  value  of  which  was 
£15,681. 

CANGICA  "WOOD,  called  also  in  England  Aiigiga.  It  is  of  a  rose-wood  color,  is  im- 
ported from  the  Brazils  in  trimmed  logs  from  eight  to  ten  inches  diameter.  As  a  variety 
in  cabinet  work,  small  quantities  of  this  wood  are  employed. 

CAXXABIC  COMPOSITION.  This  material,  for  architectural  decoration,  is  described 
by  Mr.  B.  Albano  to  have  a  basis  of  hemp,  amalgamated  with  resinous  substances,  carefully 
prepared  and  worked  into  sheets  of  large  dimensions. 

Ornaments  in  high  relief,  and  with  great  sharpness  of  detail,  are  obtained  by  pressure 
of  metal  disks,  and  they  are  of  less  than  half  the  weight  of  papier  mache  ornaments,  suffi- 
ciently thin  and  elastic  to  be  adapted  to  wall  surfaces,  bearing  blows  of  the  hammer,  and 
resisting  all  ordinary  actions  of  heat  and  cold  without  change  of  form.  Its  weather  qualities 
had  been  severely  tried  on  the  continent,  as  for-coverings  of  roofs,  &c.,  remaining  exposed 
without  injury. 

This  composition  is  of  Italian  origin,  and  in  Italy  it  has  been  employed  for  panels, 
frames,  and  centres.  It  is  well  fitted  to  receive  bronze,  paint,  or  varnish,  the  material  is  so 
hard  as  to  allow  gold  to  be  burnished,  after  gilding  the  ornaments  made  of  it. 

CANNEL  COAL.  Cannel  coal  is  obtained  in  Lancashire,  in  Derbyshire,  in  Warwick- 
shire, and  in  Scotland,  in  considerable  quantities  ;  there  are  some  other  localities  in  which 
it  is  procured,  but  not  so  extensively.  Its  use  as  a  fuel  and  for  gas  making  will  be  found  in 
the  articles  devoted  respectively  to  these  subjects. 

This  coal  has  a  dark  grayish  black  color,  the  lustre  is  glistening  and  resinous,  it  takes  a 
good  polish,  and  is  hence  made  into  a  variety  of  ornaments.  It  is  not  equal  to  jet,  (see 
Jkt,)  being  more  brittle,  heavier,  and  harder;  but  cheap  ornaments  made  of  cannel  coal 
are  not  unfrequently  sold  for  jet :  cannel  coal  is  made  up  of  horizontal  layers,  and  has  a 
grain  something  resembling  wood. 

The  coal,  when  worked  for  ornaments,  is  cut  with  a  saw,  and  the  pieces  are  rough- 
shaped  with  a  chopper.  For  making  a  snuff-box,  whether  plain,  screwed,  or  eccentric 
turned,  the  plank  way,  or  the  surface  parallel  with  the  seam,  is  most  suitable ;  it  is  also 
proper  for  vases,  the  caps  and  bases  of  columns,  &c.  Cylindrical  pieces,  as  for  tlie  shafts 
of  columns,  should  be  cut  from  either  edge  of  the  slab,  as  the  laminae  then  run  lengthways, 
and  the  objects  are  much  stronger :  cylindrical  pieces  thus  prepared,  say  3  inches  long  and 
f  of  an  inch  diameter,  are  so  strong,  they  cannot  be  broken  between  the  fingers.  Similar 
pieces  have  been  long  since  used  for  the  construction  of  flutes,  and  in  the  British  ^luseum 
m;iy  be  seen  a  snuff-box  of  cannel  coal,  said  to  have  been  turned  in  the  reign  of  Charles  I., 
antl  also  two  busts  of  Henry  VIII.  and  his  daughter  Lady  Mary,  carved  in  the  same  mate- 
rial. The  plankway  surfaces  turn  the  most  freely,  and  with  shavings  much  like  those  of 
wood  ;  the  edges  yield  small  chips,  and  at  last  a  fine  dust,  but  which  does  not  stick  to  the 
hands  in  the  manner  of  common  coal.  Flat  objects,  such  as  inkstands,  are  workccl  with  tiie 
joiner's  ordinary  tools  and  planes.  The  edges  of  cannel  coal  are  harder  and  polish  better 
than  flat  surfaces. — Holtzapffel.     See  Coal  and  Boghead  Coal. 

CANNON.     See  Artillery. 

CAOUTCHOUC,  GUM-ELASTIC,  or  INDIAN-RUBBER  {Caoutchouc,  Fr.,  Kautschuk 
Federharz,  Germ.)  occurs  as  a  milky  juice  in  several  plants,  such  as  the  xiphonia,  cahuca, 
called  also  hcvca  guiancnsi.i,  cauischur,  Jalropha  clastica,  castillcja  elastica,  cecropia  pel- 
leta,  fieus  rcligiosa  and  undica,  nrceolaria  elastica,  &c. 

The  juice  itself  has  been  of  late  years  imported.  It  is  of  a  pale  yellow  color,  and  has 
the  consistence  of  cream.  It  becomes  covered  in  the  bottles  containing  it  with  a  pellicle 
of  concrete  caoutchouc.    Its  specific  gravity  is  1-012.    When  it  ia  dried  it  loses  55  per.cent. 


"1 


288 


CAOUTCHOUC. 


of  its  weight ;  the  residuary  45  is  elastic  gum.  When  the  juice  is  heated  it  immediately 
coagulates,  in  virtue  of  its  albumen,  and  the  elastic  gum  rises  to  the  surfoce.  It  mixes  with 
water  iu  any  proportion ;  and,  when  thus  diluted,  it  coagulates  with  heat  and  alcohol  as 
before. 

I.  Caoutchouc  Manufactures. 

But  before  entering  upon  their  special  divisions  we  may  advert  to  some  of  the  steps  that 
have  created  this  new  employment  I'ur  capital,  commerce,  and  skill,  especially  as  Mr.  Han- 
cock conceives  it  but  just  to  the  memory  of  the  late  Mr.  Macintosh,  to  record  the  circum- 
stances which  led  to  his  invention  of  the  "  Waterproof  double  textures,"  that  have  been  so 
long  celebrated  through  the  world  by  the  name  of  "  Macintoshes." 

It  will  be  recollected  that,  on  the  introduction  of  coal  gas,  the  difficulties  were  very  great 
to  purify  it  from  matters  that  gave  a  most  disagreeable  odor  to  the  gas  and  gas  apparatus ; 
the  nuisance  of  these  products  led  to  many  inconveniences.  Mr.  Macintosh,  then  en)plo.yed 
in  the  manufacture  of  cudbear,  in  1819  entered  into  arrangements  with  the  Glasgow  Gas 
Works  to  receive  the  tar  and  ammoniacal  products.  After  the  separation  of  water,  ammo- 
nia, and  pitch,  the  essential  oil  termed  naphtha  was  produced,  and  it  occurred  to  him  that 
it  might  be  made  of  use  as  a  solvent  for  Indian-rubber,  and  by  the  quality  and  quantities 
of  the  volatile  naphtha,  he  could  soften  and  dissolve  the  Indian-rubber ;  after  repeated  ex- 
periments to  obtain  the  mixtures  of  due  consistency,  Mr.  Macintosh,  in  1823,  obtained  a 
patent  for  water-proof  processes,  and  established  a  manufactory  of  articles  at  Glasgow,  and 
eventually,  with  partners,  entered  upon  the  extended  scale  of  business  at  Manchester,  now 
so  well  known  as  the  firm  of  Charles  Macintosh  and  Co. 

The  action  of  many  solvents  of  Indian-rubber  is  first  to  soften  and  then  to  form  a  sort 
of  gelatinous  compound  with  Indian-rubber,  requiring  mechanical  action  to  break  the  bulk 
so  as  to  get  complete  solution,  when  the  original  bulk  is  increased  twenty  or  thirty  times 
to  form  a  mass :  it  may  be  imagined  that  in  the  early  trials  much  time  was  occupied,  and 
manual  labor,  to  break  up  the  soft  coherent  mass,  &:c.,  while  hand-labor,  sieves,  the  painters 
slab  and  muller,  and  other  simple  means  were  resorted  to. 

Macintosh,  Ilancock,  and  Goodyear  alike  record  the  simple  manipulations  they  first  em- 
ployed, and  the  impression  produced  at  the  last,  when  they  compare  their  personal  efforts 
with  the  gigantic  machinery  to  eftect  the  same  results. 

Mr.  T.  Hancock's  first  patent  was  in  April,  1820  :  "  For  an  improvement  in  the  applica- 
tion of  a  certain  material  to  various  articles  of  dress  and  other  articles,  that  the  same  may 
be  rendered  elastic."  Thus,  to  wrists  of  gloves,  to  pockets,  to  prevent  their  being  picked, 
to  waistcoats,  riding  belts,  boots  and  shoes  without  tying  and  lacing,  the  public  had  their 
attention  directed.  To  get  the  proper  turpentine  to  facilitate  solution,  and  remedy  defects 
of  these  small  articles,  and  to  meet  the  difficulties  of  practice  and  failures,  Mr.  Hancock  gave 
constant  zeal,  and  pursued  the  subject  until,  united  with  the  firm  of  C.  Macintosh  and  Co., 
he  has  been  constantly  before  the  world,  and  produced  one  of  the  most  important  manufac- 
tures known. 

To  get  two  clean  pieces  to  unite  together  at  their  recently  cut  surfaces,  to  obtain  facile 
adhesion  by  the  use  of  hot  water,  to  cut  the  Indian-rubber  by  the  use  of  a  wet  blade,  to  col- 
lect the  refuse  pieces,  to  make  them  up  into  blocks,  and  then  cut  the  lilocks  into  slices,  were 
stages  of  the  trade  which  required  patience,  years  of  time,  and  machinery  to  effect  with 
satisfaction  to  the  manufacturer. 

To  operate  upon  the  impure  rubber  was  a  matter  of  absolute  necessity  for  economic 
reasons  :  the  bottles  made  by  the  natives  v.-cre  the  purest  form,  but  larger  quantities  of  rub- 
ber could  lie  cheaply  obtained,  full  of  dirt,  stones,  wood,  leaves,  and  earth.  To  facilitate 
the  labor  of  cutting  or  dividing,  Mr.  Hancock  resorted  to  a  tearing  action,  and  constructed 
a  simple  macliine  for  the  purpose.  (See  Jiff.  140.)  a  shows  the  entrance  for  pieces  of  rub- 
ber ;  B,  interior  of  fixed  cylinder,  with  teeth  ;  c,  cylinder  to  revolve,  with  teeth  or  knives  ; 
D,  the  resulting  ball  of  rubber. 

This  machine  had  the  effect  of  tearing  the  Indian-rubber  into  shreds  and  small  fragments 
by  the  revolution  of  a  toothed  roller;  the  caoutchouc  yielded,  became  hot,  and  ultimately  a 
pasty  mass  or  ball  resulted  ;  when  cooled  and  cut  it  appeared  homogeneous.  Waste  cut- 
tings put,  in  the  first  instance,  on  the  roller,  were  dragged  in,  and  there  was  evidence  of  ac- 
tion of  some  kind  taking  place  ;  the  machine  was  stopped,  the  pieces  were  found  cohering 
together  into  a  mass,  this  being  cut  showed  a  mottled  grain,  but  being  replaced  and  sub- 
jetted  to  the  revolving  teeth  of  the  rollers,  it  became  very  hot ;  and  was  found  to  be  uni- 
formly smooth  in  texture  when  cooled  and  cut  open. 

The  first  charge  was  about  2  ounces  of  rubber,  and  required  about  the  power  of  a  man 
to  work  it.  The  next  machine  soon  formed  a  soft  solid,  with  speed  and  power,  from  all 
kinds  of  scraps  of  Indian-rubber,  cuttings  of  bottles,  lumjis,  shoes,  &c. ;  a  charge  of  one 
pound  pave  a  smooth  uniform  cylindrical  lump  of  about  7  inches  in  length  and  1  inch  in 
diameter.  This  process,  including  the  use  of  heated  iron  rollers,  was  long  kept  secret ;  it 
is  known  as  tlie  masticating  process  now,  and  the  machines  are  called  "  Masticators."     In 


CAOUTCHOUC. 


289 


140 


the  works  at  Manchester  the  charges  now  are  180  lbs.  to  200  lbs.  of  Indian-rubber  each,  and 
they  produce  single  blocks  6  feet  long,  12  or  13  inches  wide,  and  7  inches  thick,  by  steam- 
power.  The  Mammoth  machine  of  Mr.  Chauffee,  in  the  United  States,  weighs  about  30  tons, 
and  appears  to  have  been  invented  about  1837,  and  is  a  valuable  machine,  differing  in  con- 
struction from  Hancock's  masticators,  but  answers  well  in  many  respects ;  it  may  be  con- 
sidered as  the  foundation  of  the  American  trade. 

In  1820  the  blocks  were  cut  into  forms  of  square  pieces,  sold  by  the  stationers  to  rub 
out  pencil  marks,  and  then  thin  sheets  for  a  variety  of  purposes.  A  cubical  block  cut  by  a 
keen  sharp  blade  constantly  wet,  gave  a  sheet  of  Indian-rubber,  the  block  raised  by  screws 
and  the  knife  guided,  enabled  sheets  of  any  thickness  to  be  cut,  sometimes  so  even  and 
thin,  as  to  be  semi-transparent ;  when  warm,  the  sheets  could  be  joined  edge  to  edge,  and 
thus  large  sheets  be  produced :  from  these  blocks,  rollers  of  solid  rubber  could  be  made, 
cylinders  were  covered  for  machinery,  billiard  tables  had  evenly  cut  pieces  adjusted,  tubes 
and  vessels  for  chemical  use  were  employed,  and  constantly  increasing  trials  were  made  of 
the  masticated  rubber. 

These  remarks  upon  the  early  and  successful  manufacturers  will  better  enable  the 
outline  of  improvements  to  be  followed :  it  can  readily  be  imagined  that  when  capital 
and  interest  combine  with  the  changing  requirements  of  the  public,  that  it  would  de- 
mand more  space  than  a  volume  would  afford  to  give  the  insights  into  trade  applications, 
still  guarded  with  secret  means  to  produce  success.  But  the  foregoing  lemarks  may 
lead  to  the  appreciation  of  many  of  the  following  arrangements: 

I.  Of  the  Water-proof  double  Fabrics. 

In  1837,  Mr.  Hancock  obtained  a  patent  to  produce  cloth  water-proof  with  greatly  re- 
duced quantities  of  dissolved  caoutchouc,  and  in  some  cases  without  any  solvent  at  all. 
The  masticated  rubber,  rolled  into  sheets,  was  moistened  on  both  sides  with  solvent  and 
rolled  up.  The  following  day  these  were  submitted  to  rollers  of  different  speeds,  and 
the  whole  became  a  plastic  mass.  Instead  of  a  wooden  plank  as  the  bed  of  the  machine, 
a  revolving  iron  cylinder  was  used,  kept  hot  by  steam  or  water,  and  the  coated  cloth 
passed  over  flat  iron  chambers,  heated  the  same  way,  to  evaporate  the  small  quantity  of 
solvent.  Masticated  rubber  has  been  spread  without  any  solvent  by  these  machines; 
but  the  spreading  is  best  effected  by  the  rubber  being  in  some  degree  softened  by  the  ad- 
dition of  small  quantities  of  the  solvent. 

Sheets  of  rubber  have  been  prepared  by  saturating  the  cloth  with  gum,  starch,  glue, 
&c.,  then  rubber  dough  was  placed  on  this  smoothed  surface;  sufficient  coatings  of  the 
rubber  were  spread  to  make  up  the  desired  thickness,  the  cloth  was  immersed  in  warm 
water  to  dissolve  the  gum,  when  the  sheet  of  rubber  came  off  with  ease,  and  the  plastic, 
or  dough  state,  was  the  precursor  of  vulcanization  experiments  and  success. 

The  clamminess  of  caoutchouc  is  removed  by  Mr.  Hancock  in  the  following  manner: 
10  pounds  of  it  are  rolled  out  into  a  thin  sheet  between  iron  cylinders,  and  at  the  same 
-time  20  pounds  of  French-chalk  (silicate  of  magnesia)  arc  sifted  on  and  incorporated 
with  it,  by  means  of  the  usual  kneading  apparatus.  When  very  thin  films  are  reciuircd, 
(like  sheets  of  paper,)  the  caoutchouc,  made  plastic  with  a  little  naphtha,  is  spread  upon 
cloth  previously  saturated  with  size,  and  when  dry  is  stripped  off.  Mixtures  of  caout- 
chouc so  softened  may  be  made  with  asphalt,  with  pigments  of  various  kinds,  plumbago, 
sulphur,  &c. 

Vol.  III.— 19 


290 


CAOUTOHOUO. 


The  first  form  of  bags  or  pillows,  or  ordinary  air-cushions,  is  well-known,  and  manu- 
factured by  C.  Macintosh  and  Co.  as  early  as  1825  and  1826;  when  pressure  is  applied 
they  yield  for  the  instant  to  the  compressing  body,  and  then  become  rigid,  and  the  whole 
strain  is  borne  by  the  inelastic  material  of  the  bag,  which  then  resistingly  bears  the 
strain.  Mr.  T.  Hancock  once  tried  an  ordinary  pillow  between  boards  in  a  hydraulic  press, 
and  records  that  it  bore  a  pressure  of  7  tons  before  it  burst.  To  remedy  the  evils  of  this 
form  an  ingenious  arrangement  was  made  of  inserting  slips  of  Indian-rubber  into  the 
fabric,  so  that  it  expanded  in  every  direction.  This  yielding  of  the  case,  and  divisions  into 
strengthened  partitions,  enabled  seats,  beds,  and  other  applications  to  be  made.  Par- 
ticular details  will  be  found  in  Hancock's  patent  for  1835. 

The  gas  bags  so  commonly  used  appear,  by  Mr.  Hancock's  statement,  to  be  made  for 
experimental  purposes  in  the  year  1826  ;  and  in  May,  1826,  at  the  suggestion  and  for  the 
use  of  Lieut.  Drummond,  they  were  employed  in  the  Trigonometrical  Survey,  with  the 
oxy-hydrogen  jets  of  gas  on  balls  of  lime. 

They  were  made  strong  and  of  rough  materials — fustian  made  air-proof  with  thin 
sheet  rubber.  Mr.  Hancock,  to  try  whether  the  rubber  was  absolutely  impervious  to 
water,  had  a  bag  made  and  weighed  it  during  30  years;  the  decrease  of  weight  is 
shown: — 

lb 


Oct.  21st  1826 

weight 

Oct.  25th  1827 

K 

Oct.    2d    1885 

11 

Nov.          1844 

" 

Oct.           1849 

1( 

Feb.           1851 

(1 

May           1854 

(( 

b. 

oz. 

drcb 

1 

1 

4 

1 

1 

2 

1 

0 

0 

0 

14 

12 

0 

13 

4 

0 

7 

8 

0 

3 

14 

0 

3 

12 

In  1856  it  was  cut  open  and  weighed 

It  was  quite  dry.  Thus  12  oz.  of  water  had  evaporated  or  escaped  in  a  quarter  of  a  cen- 
tury, and  13  oz.  8  dr.  in  30  years  of  observation. 

He  remarks  that  bags  of  such  cloth  made  with  a  thin  coating  of  rubber,  soon  evap- 
orated sufficient  water  to  cause  mildew,  when  laid  upon  each  other;  but  this  slow  evap- 
oration does  not  interfere  with  their  ordinary  applications. 

The  porosity  of  caoutchouc  explains  the  readiness  with  which  it  is  permeated  by  dif- 
ferent liquids  which  have  no  chemical  action  upon  it.  Thin  sections  of  dry  caoutchouc 
of  the  best  kinds  absorb  from  18  to  26  per  cent,  of  water  in  the  course  of  a  month,  and 
become  white  from  having  been  brown. 

To  enumerate  the  applications  of  these  double  fabrics  for  cushions,  life-preservers, 
beds  and  boats,  would  be  out  of  place  here,  however  important  and  ingenious  the  plans. 
Thus,  instead  of  one  bag,  several  tubes  or  compartments  gave  the  required  form,  and 
this  again  may  be  divided  into  cells,  very  small,  and  kept  apart  by  wool  or  hair :  of  the 
advantage  of  this  plan  to  divide  the  air  spaces  there  can  be  no  doubt. 

For  single  texture  fabrics,  or  cloth  with  one  side  only  prepared,  the  process  is  the 
same  as  that  described  for  double  fabrics,  only  that  one  side  is  proofed,  or  covered  with 
Indian-rubber  solution  or  paste;  and  this  kind  of  water-proof  has  an  advantage  over  the 
old,  that  the  surface  worn  outside,  being  non-absorbent,  imbibes  no  moisture  and  requires 
no  drying  after  rain  or  wear.  The  objection  to  single  texture  fabrics,  of  being  liable  to 
decomposition  by  the  heat  of  flie  sun  and  from  close  packing,  has  been  obviated  by  a 
discovery  adopted  by  Messrs.  Warne  and  Co.,  termed  by  them  the  Sincalor  process,  ( si7ie 
ca/ore,  without  heat;)  by  which  the  properties  of  the  rubber  are  so  changed  that  heat, 
grease,  naphtha,  and  perspiration,  which  decomposes  the  ordinary  Indian-rubber  water- 
proof, in  no  way  affects  the  water-proof  goods  of  the  "Sincalor"  process.  The  singular 
changes  effected  by  this  process  are  especially  shown  by  the  application  of  a  hot  iron  to  the 
surface,  which  destroys  without  the  iisual  decompositions;  the  substance  is  burnt  but  is 
not  rendered  sticky.     The  process  is  stated  to  be  secret. 

II.  Vulcanization. 

Of  all  the  changes  effected  by  chance,  observation,  or  chemical  experiments  of  late 
years,  few  cases  have  been  so  important  as  the  change  in  Indian-rubber  by  the  process 
called  Vulcanization.  The  union  of  sulphur  with  caoutchouc  to  give  new  properties  so 
valuable,  that  it  may  be  said  the  former  well-known  quality  of  elasticity  is  i)ow  rendered 
so  variable  that  almost  every  range,  from  the  most  delicate  tenuity  to  the  hardness  of 
metals,  has  been  obtained  at  will  by  the  manufacturer.  These  changes  in  the  caoutchouc 
are  produced  with  a  degree  of  permanence  to  defy  air,  water,  saline  and  acid  solutions ; 
the  material  is  incapable  of  being  corroded,  and  more  permanent  under  harsh  usage  than 
any  other  set  of  bodies  in  the  world.  Such  are  the  results  of  the  processes  that  induce  a 
"change"  in  caoutchouc  when  sulphur  and  heat  are  employed  ;  where  metals  and  miner- 


CAOUTCnOUO.  291 

als  are  employed,  "metallized"  and  "mineralized,"  "  thiouized,"  and  a  number  of  other 
terms  have  been  Used. 

When  caoutchouc  is  mixed  with  sulphur  from  2  to  10  per  cent,  and  then  heated  to 
270°  and  300°,  it  undergoes  a  change,  it  acquires  new  cliaracters,  its  elasticity  is  greatly 
increased,  and  is  more  equable ;  it  is  not  affected,  nor  is  tlie  substance  altered  by  cold,  no 
climate  effects  a  change,  heat  scarcely  affects  it,  and  when  it  does  it  does  not  become 
sticky  and  a  viscid  mass;  if  it  yields  to  a  high  temperature  it  is  to  become  harder,  and 
will  ultimately  yield  only  at  the  advanced  temperature  to  char  and  to  decompose.  All  the 
ordinary  solvents  are  ineffectual.  The  oils,  grease,  ether,  turpentine,  naphtha,  and  other 
solvents  scarcely  alter  it,  and  the  quantity  of  sulphur  that  will  effect  the  change  is  known 
not  to  exceed  1  or  2  per  cent.  Furtlier,  if  peculiar  solvents,  such  as  alkalies,  remove 
all  apparent  sulphur  from  it,  still  the  change  remains;  indeed,  the  analogy  of  steel  to 
iron  by  the  changes  of  condition  effected  by  some  small  quantities  of  other  bodies  seems 
to  be  an  analogous  condition.  Whatever  the  theory,  which  is  exceedingly  obscure,  still 
the  practice,  by  whatever  name,  is  to  obtain  this  changed  state  and  exalted  elastic  prop- 
erties. 

"Vulcanization"  had  its  discovery  in  America.  Mr.  Goodyear  relates  that,  having 
made  a  contract  for  Indian-rubber  mail  bags,  they  softened  and  decomposed  in  service, 
and  while  he  thought  a  permanent  article  had  been  made,  the  coloring  materials  and 
the  heat  united  to  soften  and  to  destroy  the  bags;  hence,  by  this  failure,  distress  of  all 
kinds  arose,  and  the  trade  was  at  an  end.  During  one  of  the  calls  at  the  place  of  aban- 
doned manufacture,  Mr.  Goodyear  tried  a  few  simple  experiments  to  ascertain  the  effect 
of  heat  upon  the  composition  that  had  destroyed  the  mail  bags,  and  carelessly  bringing 
a  piece  in  contact  with  a  hot  stove,  it  charred  like  leatlicr.  He  called  the  attention  of 
his  brother,  as  well  as  other  individuals  who  w^cre  present,  and  who  were  acquainted  with 
the  manufacture  of  gum  elastic  to  the  fact,  as  it  was  remarkable,  and  unlike  any  before 
known,  since  gum  elastic  always  melted  when  exposed  to  a  high  degree  of  heat.  The 
occurrence  did  not  at  the  time  appear  to  them  to  be  worthy  of  much  notice.  He  soon 
made  other  trials,  the  gum  always  charring  and  hardening. 

As  ordinary  Indian-rubber  is  always  tending  to  adhere,  many  plans  have  been  tried 
to  prevent  this.  Chalk,  magnesia,  and  sulphur  had  been  patented  in  England  and  Amer- 
ica, but  no  one  seems  to  have  supposed  any  other  change  would  be  produced  by  heat. 
Mr.  Goodyear  proceeded  to  try  experiments,  and  produced  remarkable  results;  samples 
of  goods  were  shown  about  and  sent  to  Europe. 

The  late  Mr.  Brockedon,  so  well  known  for  his  talents  and  love  of  scientific  investiga- 
tions, had  long  pursued  means  to  obtain  a  substitute  for  corks,  and,  after  much  ingenuity, 
had  devised  Indian-rubber  stoppers.  As  soon  as  all  mechanical  difficulties  were  over, 
objections  were  taken  to  the  color  of  the  substance.  Some  samples  of  a  changed  rubber 
came  into  his  possession,  of  which  it  was  declared  they  would  keep  flexible  in  the  cold, 
and  were  found  not  to  have  an  adhesive  surface.  These  caused  numerous  experiments, 
as  it  was  recognized  that  a  change  had  been  effected,  and  although  Mr.  Brockedon  failed, 
yet  Mr.  Hancock  kept  on  working,  combining  sulphur,  with  every  effect  but  that  of  vul- 
canization, as  he  was  ignorant  of  the  power  of  heat  to  effect  this  change.  He  used  melt- 
ed sulphur,  and  produced  proof  of  absorption,  for  the  pieces  of  caoutchouc  were  made  yel- 
low throughout ;  by  elevating  the  temperature  he  found  they  became  changed,  and  then 
the  lower  end  of  slips  "nearest  the  fire  turning  black,  and  becoming  hard  and  horny," 
(the  sulphur  was  melted  in  an  iron  pot.)  By  these  siuiple  observations,  as  they  now 
seem,  Mr.  Goodyear  in  America  and  Mr.  Hancock  in  England,  were  induced  to  take  out 
patents,  and  commence  that  series  of  manufacturing  applications  to  which  there  seems 
no  limit.  The  first  English  patent  was  by  Mr.  Hancock.  The  general  method  is  to  in- 
corporate sulphur  with  caoutciiouc,  and  submit  it  to  heat;  if  any  particular  form  is  re- 
quired, the  mixture  is  placed  in  moulds,  and  takes  off  any  delicate  design  that  may  be 
upon  the  iron  or  metal  mould,  and  if  these  are  submitted  to  higher  degrees  of  heat,  the 
substance  and  evolved  gases. expand,  and  thus  a  very  hard,  horny,  or  light  but  very 
strong  substance  is  produced,  called  hard  Indian-rubber,  or  "  vulcanite."  Mouldings, 
gun-stocks,  combs,  cabinet  work,  and  hundreds  of  forms  may  be  obtained  by  these 
curious  means.  The  term  vulcanization  was  given  by  Mr.  Brockedon  to  this  process, 
which  seems  by  the  employment  of  heat  and  sulphur  to  partake  of  the  attributes  of  the 
Vulcan  of  mythology.  For  the  "change"  or  "vulcanizing"  to  got  a  yielding  but  per- 
manently elastic  substance,  steam  heat  is  usually  employed  in  England,  but  in  America, 
.ovens,  with  various  plans  for  producing  dry  heat,  are  generally  employed. 

The  articles  thus  made  being  more  clastic,  unaffected  by  heat,  cold,  or  solvents,  at- 
tracted much  attention,  and  Mr.  Parkes  was  engaged  to  find  out  a  method  of  producing 
the  same  effects  now  secured  by  patent:  all  ordinary  means  were  used  and  given  up,  but 
he  finally  succeeded.  The  process  of  cold  sulphuring  of  Mr.  Parkes  consists  in  plunging 
the  sheets  or  tubes  of  caoutchouc  in  a  mixture  of  100  parts  of  sulphuret  of  carbon,  and 
2^  parts  of  protocliloride  of  sulphur,  for  a  minute  or  two,  and  then  immersing  them  in 


292 


CAOUTCHOUC. 


cold  water.  Thus  supersulphuration  is  prevented  in  consequence  of  decomposing  the 
chloride  of  sulphur  on  the  surface  by  this  immersion,  while  the  rest  of  the  sulphur  passes 
into  the  interior  by  absorption.  Mr.  Parkes  prescribes  another,  and  perhaps  a  prefer- 
able process,  which  consists  in  immersing  the  caoutchouc  in  a  closed  vessel  for  3  hours, 
containing  a  solution  of  polysulphuret  of  potassium  indicating  a  density  of  26"  Beaumo 
at  the  temperature  of  248°  Fahr.,  then  washing  in  au  alkaline  solution,  and  lastly  in  pure 
water.     A  uniform  impregnation  is  thus  obtained. 

In  the  first  instance  sulphur,  caoutchouc,  and  heat  were  alone  employed.  The  tempera- 
ture and  the  time  to  which  the  mixtures  are  subjected  to  heat  afford  conditions  to  be  best 
understood  by  the  practical  man.  Vulcanized  rubber  now  is  not  only  the  changed  sub- 
stance as  produced  by  sulphur,  but  it  contains  metallic  oxides,  &c.  Metallic  and  mineral 
substances,  and  these  compounds,  are  perhaps  much  better  fitted  for  their  respective  uses 
than  the  pure  sulphur  and  Indian-rubber.  'NVhite  lead,  sulpliuret  of  antimony,  black  lead, 
and  other  substances  enter  into  these  combinations.  Alter  the  early  experiments  with  vul- 
canized rubber,  there  seemed  reason  to  believe  that  changes  slowly  took  place.  The  rubber 
was  found  to  become  brittle,  and  bands  stretched  out  broke  immediately.  To  a  great  ex- 
tent this  has  been  remedied  by  the  use  of  lead,  which  seems  to  combine  with  the  sulphur, 
for  changes  are  believed  by  practical  men  to  take  place  with  pure  elastic  vulcanized  caout- 
chouc, which  do  not  occur  when  metallic  matters  are  duly  mixed.  This  is  a  trade  statement, 
which  may  be  true  for  some  special  uses.  The  brittleness  may  perhaps  more  fairly  be  ad- 
mitted to  be  due  to  inexperience,  and  the  difBculties  to  meet  the  demands  of  the  public  for 
a  new  article  ;  but  to  those  whom  it  may  most  concern,  we  have  raised  this  question  so  far 
as  to  obtain  the  conscientious  opinion  of  Mr.  Thomas  Hancock,  (now  retired  from  business,) 
who  considers  that  by  the  peculiar  plan  of  vulcanizing  by  a  bath  of  sulphur,  and  employing 
high-pressure  steam,  (described  in  Patent  of  1843,)  he  obtains  what  he  calls  jiure  vulcaniz- 
ing, that  is,  the  use  of  sulphur,  rubber,  and  heat.  He  states  "  That  by  this  mode,  the 
greatest  amount  of  extensile  elasticity  is  obtained,  and  that  this  quality  is  diminished  in 
proportion  as  other  matters  are  present  in  the  compound."  It  may,  however,  be  useful  to 
record  some  of  the  results  of  early  trials  made  by  competent  authorities,  with  the  view  of 
testing  its  ultimate  employments.  Mr.  Brockedon  stated  at  the  Institution  of  Civil  Engi- 
neers, that  he  had  kept  vulcanized  Indian-rubber  in  tranquil  water  for  14  years  without  vis- 
ible change,  and  he  summed  up  the  then  knowledge  of  trade  production,  that  there  was  per- 
haps no  manufacturing  process  of  which  the  rationale  was  so  little  understood  as  that  of 
vulcanizing  caoutchouc  ;  all  was  conducted  on,the  observation  of  facts,  a  given  quantity  of 
sulphur  to  a  certain  thickness  of  rubber,  at  a  certain  temperature  ;  and  certain  results  were 
reckoned  upon  with  confidence,  but  more  from  practice  than  theory.  Mr.  Brockedon  had 
placed  vulcanized  rubber  for  10  years  in  damp  earth,  and  it  exhibited  no  change. 

When  articles  were  moulded,  the  metal  of  the  mould  was  not  a  matter  of  indifference  ; 
if  of  tin,  the  article  was  usually  delivered  perfectly  clean,  but  if  of  brass  or  copper,  then 
the  material  adhercjd  to  it,  probably  from  the  greater  affinity  of  the  sulphur  for  the  metal 
than  for  the  caoutchouc :  these  surface  effects  may  well  be  borne  in  mind,  for  it  appears 
not  to  be  an  easy  matter  to  vulcanize  large  masses  of  caoutchouc,  while  sheets  and  thin  films 
are  readily  changed.  The  soft  masses  of  materials  are  placed  in  moulds,  strongly  secured, 
if  a  high  temperature  is  to  be  used,  and  the  mass  comes  out  with  the  form  thus  given  to  it, 
and  more  or  less  elastic ;  hence  the  surface  of  a  mass  is  always  likely  to  be  advanced  in  the 
vulcanizing  changes. 

At  present,  a  very  large  proportion  of  the  articles  made  have  the  forms  given  to  them 
in  the  plastic  state,  and  then  subjected  to  heat ;  the  change  is  effected,  and  they  retain  their 
form,  although  rendered  permanently  elastic. 

Mr.  Brockedon  and  Mi-.  Brunei  tried  this  substance  on  the  Great  "Western  Railway  in 
place  of  felt,  to  be  used  between  the  under  sides  of  bearing  rails  and  sleepers  of  railways. 
It  appeared,  by  constant  trials  of  nearly  a  year,  to  be  quite  indestructible  to  any  action  to 
which  it  had  been  exposed  ;  the  slips  were  indented  by  the  edge  of  the  rail,  but  not  per- 
manently so,  and  the  surface  was  glazed,  as  if  by  friction ;  the  slips  were  6  inches  wide, 
and  weighed  8  oz.  to  the  yard  in  length ;  the  transit  of  the  carriages  was  easier  over  that 
part  of  the  line. 

To  test  the  power  of  endurance  to  heavy  blows,  Mr.  Brockedon  subjected  a  piece  of 
vidcanized  Indian-rubber,  1  h  inches  thick  and  2  inches  area,  to  one  of  Nasmyth's  steam 
hammers  of  5  tons  ;  this  first  rested  on  the  rubber  without  effect,  then  was  lifted  2  feet  and 
dropped  upon  it  without  injury,  then  lifted  4  feet,  the  vulcanized  cake  was  torn,  but  its 
elasticity  was  not  destroyed.  Still  more  severe  trials  were  made ;  a  block  of  vulcanized 
caoutchouc  was  placed  as  between  cannon  balls,  with  the  whole  power  of  the  heaviest  steam 
hammers  employed,  but  the  iron  spheres  split  the  block,  and  the  elasticity  of  the  vulcanized 
caoutchouc  was  not  destroyed. 

The  natural  and  the  vulcanized  rubber  have  both  been  proposed  as  absolutely  resisting 
the  power  of  .shot  and  rifle  balls.  Instructive  cases  are  known  of  projectors  offering  to  be 
clothed  in  their  own  cuirasses,  and  meet  the  charge  of  a  fired  rifle  ;  when  a  deal  board  or  leg 


CAOUTCHOUC. 


293 


of  mutton  has  been  substituted  in  tlie  interior,  they  have  been  found  perforated  by  the  rifle 
ball,  while  back  and  front  the  cuirass  showed  no  change,  the  truth  being  that  the  bullet  cut 
its  way  through,  and  the  edges  of  the  aperture  closed  and  joined,  so  that,  no  hole  being 
visible,  led  to  the  conclusion  that  the  ball  had  declined  to  penetrate  the  rubber. 

Among  the  applications  may  be  named  the  construction  of  boats  and  pontoons.  On  the 
first  trial  in  the  Arctic  regions,  they  were  adopted  to  give  possible  conveyance  when  other 
boats  could  not  be  carried  ;  the  Indian-rubber  boat  soon  won  its  character ;  it  took  the  icy 
channels,  and  bore  the  brunt  of  all  collisions,  and  without  damage  met  rock,  and  ice  and 
storm,  where  it  was  believed  no  other  boat  could  live.  Since  then,  they  have  been  employed 
on  the  rivers  of  Africa  by  missionaries  and  travellers,  and  on  lakes  in  England. 

Sheets  of  enormous  size, — ship-sheets, — have  been  made  50  yards  long,  and  56  inches 
wide,  others,  10  feet  square  ;  these  are  proposed  to  pass  over  a  steam-vessel's  side,  to  adapt 
a  valve,  fix  a  pipe,  or  repair,  from  the  interior,  the  vessel  itself  without  going  into  dock. 
These  stout  sheets,  f  inch  thick,  are  let  down  by  ropes  over  a  ship's  side,  and  brought  over 
the  hole  or  place  for  repair  by  the  pressure  of  the  water  on  the  elastic  sheet,  the  leak  may 
be  stopped  and  the  ship  pumped  dry,  pipes  renewed,  shot-holes  and  leaks  stopped.  In- 
deed, an  early  application  of  compounds  of  native  rubbers  and  other  materials  was  applied 
directly  as  sheatliing  for  ships  with  success ;  but  litigation  among  the  parties  caused  the 
business  to  cease.  Since  the  various  plans  for  getting  a  flexible  material  have  been  success- 
ful, there  seems  no  doubt  but  many  unexpected  applications  will  be  made. 

Messrs.  Macintosh  had  coated  some  logs  of  wood  with  vulcanized  Indian-rubber,  and 
caused  them  to  be  towed  in  the  wake  of  a  vessel  all  the  way  to  Demerara  and  back,  and  it 
was  found  that  the  coated  logs  were  quite  intact,  while  the  uncoated  timber  was  riddled  by 
marine  insects.  The  same  firm  stated  :  "  That  the  only  effect  they  could  trace  upon  long 
immersed  vulcanized  caoutchouc,  was  a  slight  change  of  color,  perhaps  a  hydrate  produced 
by  superficial  absorption,  but  this  change  of  color  disappeared  on  being  dried.  If  they  were 
called  upon  to  select  a  situation  for  the  substance  to  retain  its  properties  for  the  longest  pe- 
riod, they  would  select  immersion  in  water.  After  years  of  experience  in  the  use  of  hose- 
pipes, pipe-joints,  valves  for  pumps  and  steam-engines,  they  had  never  known  an  injury 
from  the  contact  of  any  kind  of  water." 

Mr.  Goodyear  sums  up  the  advantages  of  vulcanized  rubber  under  the  following  heads, 
as  being  either  properties  new,  or  superior  to  those  possessed  by  the  natural  caoutchouc  : — 

1.  Elasticity. 

2.  Pliability. 

3.  Durability. 

4.  Insolubility.  10 
6.  [Inalterability  by  climate,  or  artificial 

heat,  or  cold. 

6.  Inadhesiveness.  11 

7.  Impermeability    to    air,    gases,    and  12 

liquids. 

We  are  indebted  for  the  following  facts  and  remarks  to  Messrs.  Silver  and  Co.,  of  Lon- 
don and  Woolwich : 

The  chief  improvements  operated  in  caoutchouc  by  the  process  of  vulcanization,  are  the 
properties  of  resisting  and  remaining  unaffected  by  very  high  degrees  of  heat  and  cold,  and 
increased  compressibility  and  elasticity.  In  its  natural  state,  Indian-rubber  becomes  rigid 
by  exposure  to  cold,  and  soft  and  plastic  by  heat,  under  the  action  of  boiling  water.  Arti- 
cles manuf\ictiired  of  this  substance  suffer  and  lose  the  qualities  which  constitute  their  value 
in  cold  and  in  hot  countries.  A  piece  of  Indian-rubber  cloth,  for  instance,  taken  to  Moscow 
In  December  or  January,  would  assume  all  the  qualities  of  a  piece  of  thin  sheet  iron,  or 
thick  pasteboard  ;  the  same  cloth  would  in  India  or  Syria  become  uncomfortably  pliable, 
and  present  a  moist  and  greasy  appearance  ;  and,  indeed,  after  being  folded  up  some  time, 
it  will  be  found  to  be  glued  together.  Nothing  but  vulcanization  insures  the  equable  condi- 
tion of  the  articles  in  the  most  intense  cold,  and,  in  heat  up  to  and  above  300',  makes  In- 
dian-rubber fit  for  practical  purposes.  These  advantages  have  conduced  to  its  being  very 
extensively  used  in  comieetion  with  machinery  of  every  description  ;  and  as  steam  power 
is  still  further  employed,  and  as  the  numerous  other  advantages  possessed  by  vulcanized 
Indian-rubber  become  known,  (for  it  is  only  of  late  that  any  idea  of  their  extent  has  been 
realized,)  its  application  will  be  extended  and  proportionally  its  consumption  increased. 

The  compressibility  and  the  return  to  its  former  dimensions,  when  the  jtressure  has 
ceased,  in  one  word,  the  elasticity  of  the  Indian-rubber,  is  increa.sed  to  such  a  degree  by 
vulcanization,  that  comparing  the  improved  with  the  original  article,  it  maybe  said  that  the 
native  Indian-rubber  is  almost  devoid  of  elasticity.  The  high  degree  of  elasticity  which  it 
obtains  by  vulcanization  is  shown  by  the  results  of  the  following  experiments,  in  which  a 
block  of  the  vulcanized  Indian-rubber,  of  the  kind  used  for  the  manufacture  of  railway  car- 


8.  Plasticity. 

9.  Facility  of  receiving  every  style  of 
printing. 

Facility  of  being  ornamented  by 
painting,  bronzing,  gilding,  japan- 
ning, and  mixing  with  colors. 

Non-electric  quality. 

Odor. 


294  CAOUTCHOUC. 

riage  springs,  measuring  -6  inches  outside  disk,  1  incli  inside  disli,  and  6  inches  deep,  was 
taken  and  exposed  to  pressure  : — 

A  pressure  of  ^  ton  reduced  it  to  - 


ditto 

1 

ditto 

ditto 

U 

ditto 

ditto 

2 

ditto 

ditto 

2i 

ditto 

ditto 

3 

ditto 

ditto 

H 

ditto 

57,  a 

deep 

5'/.  6 

do. 

47>B 

do. 

47.6 

do. 

3'7,6 

do. 

3"ia 

do. 

H 

do. 

3 

do. 

ditto        4  ditto  ... 

The  block  was  left  under  pressure  for  48  hours,  and  in  each  case  returned  to  its  original 
dimensions  after  a  short  period  when  the  pressure  was  removed. 

Indian-rubber  and  canvas  hose  are  now  generally  used  where  leathern  pipes  were  used 
in  former  times,  viz.  where  a  flexible  tube  is  required,  in  fact,  where  it  is  not  possible  to 
use  a  metal  pipe.  The  advantages  which  the  Indian-rubber  and  canvas  hose  has  over  the 
leathern  pipe,  are,  that  it  does  not  require  draining  and  greasing  after  being  used,  that  it 
can  be  left  in  the  water  without  rotting,  and  that  it  does  not  harden  or  lose  its  flexibility. 
Leathern  pipes,  on  the  contrary,  require  the  most  careful  treatment,  and  even  with  the 
greatest  care  they  are  liable  to  frequent  leaking.  Indian-rubber  and  canvas  hose  are  made 
to  resist  atmospheric  and  hydraulic  pressure,  say  up  to  1,000  lbs.  pressure  on  the  square 
inch.  Of  this  Indian-rubber  and  canvas  hose,  the  descriptions  mostly  in  use  are  the  fol- 
lowing : — 

1  Ply  which  will  stand  a  pressure  of  about       -         -         20  lbs.  to  square  inch. 

2  Ply  for  conducting  water  "  -        SO  to  40  " 

2  Ply  stout  "  -        -        75  " 

3  Ply  for  brewers,  &c.  "  -         -         75  " 

4  Ply  for  steam  and  fire-engines    "  -         -       175  " 

Among  the  most  recent  uses  of  Indian-rubber  and  canvas,  are  those  of  its  manufacture 
into  gas  and  ballast  bags  ;  the  former  are  used  for  the  transport  of  gas,  and  applied  to  the 
various  emergencies  of  gas  engineering.  Indian-rubber  gas  tubing  is  now  in  general  use, 
the  great  advantage  over  metal  tubes  being  the  case  with  which  gas  can  be  conveyed  to 
whatever  part  of  the  building  it  may  be  required ;  this,  where  any  alterations  are  being 
effected,  is  a  great  desideratum.  Ballast  bags,  large  stout  bags  of  Indian-rubber  and  can- 
vas, capable  of  holding  from  1  to  5  or  10  tons  of  water,  are  coming  into  use  as  the  most 
convenient  form  of  ballast,  thus  saving  valuable  space,  which  is  made  available  for  cargo. 
These  bags  may  be  emptied  at  any  time,  and  when  flattened  down  and  rolled  up,  they  can 
be  stowed  away.  Indian-rubber  bags  for  inflation  have  also  in  a  few  cases  been  made  use 
of  for  buoying  up  vessels,  but  hitherto  the  practice  has  been  experimental  only,  and  such 
floating  machines  are  not  as  yet  generally  in  use. 

The  vulcanizing  Indian-rubber  on  silk  or  woollen  was  for  a  long  time  considered  im- 
practicable, because  the  process  of  vulcanization  destroyed  the  fibre  and  texture  of  the  two 
substances ;  and  it  is  stated  that  now  this  process  is  effected  in  a  manner  which  deprives 
neither  silk  nor  wool  of  their  natural  qualities  and  strength.  By  this  improvement,  com- 
bined with  Silver's  patent  process  of  annihilating  the  unpleasant  smell  which  all  Indian- 
rubber  goods  used  to  acquire  in  the  process  of  manufacture,  the  advantages  of  that  sub- 
stance for  clothing  purposes  are  extended  to  the  lightest  and  the  warmest  of  our  textures. 
Silk  and  Indian-rubber  garments  are  made  without  any  deterioration  of  the  strength  and 
durability  of  the  stuff,  while  they  are  perfectly  free  from  odor  of  any  kind.    (See  page  302.) 

III.  Mechanical  Applications  of  Caoutchouc. 

Numerous  important -applications  of  caoutchouc  have  been  made  in  the  mechanical  arts, 
among  which  we  may  mention  springs  for  railway  and  common  road  carriages,  military 
carriages,  lifting  springs  for  mining  ropes  and  chains,  towing  ropes  and  cables,  rigging  of 
ships,  recoil  of  guns  on  ships,  the  tires  and  naves  of  railway  and  other  wheels,  to  axles  and 
axle  l)earings,  to  windows  of  railway  carriages,  railway  switches,  bed  of  steam-hammer, 
couplings  for  locomotives  and  tenders,  packing  for  steam  and  water  joints,  shields  for  axle 
boxes,  sockets  for  water  pipes.  Viands  for  driving  machinery,  valves  for  pumps,  tubes  for 
conveying  acids,  beer,  water,  and  other  fluids,  packing  for  pistons. 

Many  of  these  improvements  have  been  the  subject  of  patents,  a  list  of  the  principal  of 
which  is  given,  stating  the  name  of  patentee,  date,  and  object  of  so  much  of  patent  as  re- 
lates to  the  use  of  caoutchouc. 


Lacey 
Melville     - 

3  Walker  and  Mills 

4  W.  C.  Fuller     - 


29th  Mar.,  1825 
13th  April,  1844 


3d   July,   1845 
23d    Oct.,   1845 


5     Adams  and  Richardson   24th  Mav   184'7 


C.  De  Bergue 

Y  I  Wrighton 

8  C.  De  Bergue 

9  Normanville 

10  C.  De  Bergue 

11  P.  R.  Hodge 

12  G.  Spencer 

13  P.  R.  Hodge 


W.  Scott 

J.  E.  Coleman 


16  I  Fuller  and  Knivett 
C.  De  Bergue    - 
G.  Spencer 
R.  E.  Hodges    - 


G.  De  Bergue 
W.  C.  Fuller 


E.  Lund    - 

W.  C.  Fuller 

E.  Miles    - 
G.  Richardson 

W.  Scott  - 

G.  Spencer 

R.  Eatou  . 
R.  Eaton  - 


26th  July,  1847 

22d  Dec,  1847 
5th  Jan.,  1848 

2d  May,    1848 
1 5th  April,  1850 

8th  Mar.,  1852 
2d  Feb.,   1852 

8th  Mar.,  1852 


8th  Mar.,  1852 
2d  June,  1852 

6th  Oct.,  1852 

26th  Mar.,  1853 

!  2d  July,  1853 

2d  Nov.,  1854 

4th  Mar.,  1854 
10th  May,  1854 

i  18th  Aug.,  1854 

10th  Jan.,  1855 

12th  Jan.,  1855 
28th  Nov.,  1855 

14th  May,  1856 

25th  July,  1856 

20th  Nov.,  1856 
8th  Dec,  1856 


H.  Bridges  -  .  14th  Mar.,  1857 
J.  Williams  -  -  11th  Nov.,  1857 
W.  E.  Nethersole      - 


Indian-rubber  springs  for  carriages  en 
closed  in  cases  with  dividing  plates 
Springs  for  buffers  and  bearing,  sphere" 
of  Indian-rubber  and  air,  withdivid- 
ing  plates,  and  enclosed  in  iron  cases 
Buffers,  Indian-rubber  bags,  enclosing 
air,  in  iron  cases.  ° 

Buffer  and  bearing  springs  of  Indian- 
rubber,  cylindrical  rings  with  divid- 
ing plates  of  iron. 
Elastic  packing  for  axles. 
Indian-rubber  buffer,  bearing  and  draw 

springs. 
Indian-rubber  shield  for  axle  box 
Anti-recoil  buffers  of    Indian-rubber 
and  improvements  in  dividino-  plate^' 
Indian-rubber  shield  for  axle  box. 
Station  buffers  of  Indian-rubber    and 

carriage  buffers.  ' 

Packing  for  steam  joints. 
Indian-rubber  cones  as  buffer,  bearing 
and  draw  springs.  *' 

Indian-rubber  compound  springs,  In- 
dian-rubber to  wheel  naves,  and  to 
axle  box  shields. 
Indian-rubber  as  check  springs,  wheel 

nave,  suspensor  springs. 
Indian-rubber  applied  to  buffer,  bear- 
ing, ^nd  draw  springs,  rails,  chairs 
and  sleepers,  wheel  tires,  windows 
axlebearings,  plummer  blocks,  con- 
necting  rods,  steam  hammer  beds 
Common  road  springs  of  Indian-rub- 
ber. 

Indian-rubber  bearing  sprin"-s      (Pat- 
ent refused.)  °  " 
Improved   cones   for   buffer,    bearing. 
I      and  draw  sprint^s. 

Improvements  in  fastening  Indian-rub- 
ber springs. 

Buffers  for  railways. 

Indian-rubber  springs  applied  to  an- 
chors, cables,  towing  ropes,  deck 
ropes, 

Indian  rubber  to  feed-pipe,  coupling 
and  water  joints. 

Indian-rubber  springs  to  common 
roads. 

Indian-rubber  to  water-pipe  couplings. 

Indian-rubber -buffers  with  Spencer's 
cones. 

Indian-rubber   to   axles   and  tires  of 

wheels. 
Indian-rubber  to  feed-pipe,  couplings 

for  locomotives  and  tenders. 

Indian-rubber  springs  for  railways. 

Indian-rubber  springs  in  thin  lam'ina; 

for  buffer,  bearing,  and  draw  springs 

and  lifting-purposes.  ' 

Spencer's  cones  applied  to  wood  blocks 

m  buffers,  bearing  springs,  &c. 
Indian-rubber  springs  applied  to  the 
side  or  safety  chains  of  trucks,  &c 
Do.  do.  do. 


296 


CAOUTCHOUC. 


We  have  been  at  some  pains  to  ascertain  the  progress  that  has  been  made  in  the  prac- 
tical application  of  these  inventions,  and  notice  them  below,  under  the  several  heads 
mentioned  above. 

Springs. — The  first  proposal  to  use  caoutchouc  for  springs  that  we  are  aware  of,  oc- 
curs ia  Laceyh  patent,  (see  list,)in  1825,  when  blocks  of  caoutchouc  were  proposed  to  be 
used,  having  dividing  plates  of  iron  between  each  series;  but  little  seems  to  have  been 
done  towards  any  practical  application  at  that  time  :  later  in  1844,  (see  hst,)  Melville  pro- 
posed to  use  spheres  of  caoutchouc,  enclosing  air,  and  separated  by  disks  of  wood  or 
metal,  the  whole  being  enclosed  in  iron  cases,  and  used  for  buffers  and  bearing  springs 
for  railway  carriages.  In  1845,  (see  list,)  Walker  and  Hills  proposed  to  use  bags  of 
caoutchouc  enclosing  air,  and  contained  in  cases  of  iron,  for  use  as  buffer  springs. 

The  next  improvement  is  contained  in  Fuller's  patent  of  1845,  which  consists  in  the 
use  of  cylindrical  rings  of  vulcanized  Indian-rubber,  ia  thicknesses  varying  from  -J  to  3 
inches,  and  with  diameter  of  ring  suitable  to  the  power  of  spring  required;  between  eacli 
of  these  cylindrical  rings  he  places  a  thin  iron  plate,  through  a  hole  in  the  centre  of 
which  passes  a  guide  rod.     Mg.  141  shows  Fuller's  spring  in  section  and  plan.     These 


^^- 


141 

m 


xd 


springs  have  been  extensively  used  as  buffer,  bearing,  and  draw  springs  for  railway  uses 
alone  and  in  combination  with  Be  Bergue's  improvements :  some  defects  have  been  found 
in  practice  in  this  form,  to  obviate  which,  the  ingenuity  of  later  inventors  has  been  ex- 
ercised ;  the  defects  alluded  to  are,  the  tendency  to  swell  out  at  the  central  unsupported 
part  of  the  ring,  thus  from  the  undue  tension  rendering  it  liable  to  break  under  sudden 
concussion,  and  occasioning  complete  disintegration  of  the  material  where  not  breaking. 
To  obviate  these  defects,  George  Spencer  (see  Hst,  Nos.  12, 18)  proposed  to  mould  the 
caoutchouc  at  once  in  the  form  it  assumes  under  pressure,  and  then  to  place  a  confining 
ring  of  iron  on  the  larger  diameter.     (See  Jig.  142.)    By  this  ingenious  plan,  the  caout- 

142 


a 

-- 

— 

^ 

chouc  loses  its  power  of  stretching  laterally,  being  held  by  the  ring  b,  secured  in  a  groove 
moulded  in  the  cone  to  receive  it ;  when  the  pressure  is  applied  to  the  ends,  the  rubber 
is  squeezed  into  the  cup-like  spaces  c,  and  thus  the  action  of  the  spring  is  limited.  By 
this  plan,  rubber  of  a  cheaper  and  denser  kind  can  be  used  than  on  the  old  cylindrical 
plan,  and  the  patentee  states  that  many  thousands  of  carriages  and  trucks  are  fitted  with 
these  springs  which  give  entire  satisfaction ;  among  which,  are  those  on  the  Brighton, 
South-Western,  North  London,  South  Wales,  Vale  of  Xeath,  Bristol  and  Exeter,  Taff 
Yale,  Lancashire  and  Yorkshire,  St.  Helen's,  Bombay  and  Baroda,  Thciss  Railways,  and 
many  others.  These  cones  are  used  as  buffer,  bearing,  and  draw  springs  for  railway  car- 
riages, and  are  made  in  several  sizes  to  suit  various  uses.     To  show  the  power  that  such 


CAOUTCHOUC. 


297 


springs  are  equal  to,  we  append  tlie  result  of  an  experiment  on  a  No.  1  cone,  (for  inside 
buffers,)  3  inches  iu  length,  3J  inches  diameter  at  ring,  5  inches  diameter  of  ring. 

1st  Experhnoit,  without  the  confining  ring,  weight  of  cone  1:|-  lbs. 

Inches.  Giving  a  stroke  of 

Without  any  pressure  the  cone  measured     -         -         3         -         - 
With  pressure — 280  lbs.  "  -         -         24-       -         -  -|  inch. 

'«  — 148  lbs.  "  .         .         2         -         -  1      " 

"  —672  lbs.  "  .         .  u       .         .  u  " 

2c?  Experiment. 
With  the  confining  ring  6,  on  the  same  double  cone ;  the  following  were  the  results: — 
Without  any  pressure  the  cone  measured      -    .     -         -         3  inches,  as  before. 
With— 448  lbs.  "  "  ...         9i     u 

With— 1,680  lbs.  "  "  .         .         .         2       " 

With— 2,912  lbs.  "  "  -         -         -         If     " 

With— 15,680  lbs.        "  "  -         -         -         H     " 

The  advantages  are  stated  to  be,  less  first  cost  than  steel ;  less  weight,  6  cwt.  being  saved 
in  each  carriage  by  their  use ;  and  great  durability. 

Coleman^s  improvement  (see  list.  No.  15)  consists  in  the  use  of  iron  rings  to  confine 
the  lateral  swelHng  of  Indian-rubber  cylinders.    (See  Jig.  143.)    They  are  used  as  bearing 

143 


springs  for  engines  and  tenders  on  the  North-Western  railway,  by  J.  E.  M'Connell,  Esq., 
who  prefers  them  to  steel,  as  being  easy  in  action,  durable,  safe,  and  easy  of  repair;  they 
are  used  also  as  buffers  and  draw-springs,  but  not  to  the  extent  of  Fuller's  and  Spencer's 
form.  To  give  an  idea  of  the  power  of  such  a  spring,  we  append  the  result  of  an  experi- 
ment of  one  that  we  witnessed  at  Messrs.  Spencer  and  Co.'s. 

Experiments  with  one  of  Coleman's  cylinders  with  and  without  the  rings.     Cylinder 
6  inches  long,  6  inches  diameter,  1  inch  hole,  weight  9  lbs. 

■Without  the  confining  rings.        With  the  2  confining  rings. 
Tons  pressure.  Inches  Length.  Inches  Length. 

0  ....  6         -         -         -         .         6 

i  -         -         •         -  5Vi8   -         -         -         .         5'Vio 

1  ....  5         .         .         .         .         5| 

H  -         -         -  ■      -  41       -         -         -         -         5i 

2  ....  4i       -         -         -         .         5A 
2i         -         -         -         -  3f       -         -         -         -         5i 

The  ne.xt  form  of  these  springs  is  R.  Eaton's,  (sce/y.  144  ;  and  list,  Nos.  28,  29.)    This 

144 


298 


CAOUTCHOUO. 


spring  seems  to  be  peculiarly  adapted  to  use  where  a  powerful  spring,  acting  through  a 
small  space,  and  taking  little  roon;,  is  required,  as  for  use  in  mining  ropes  and  chains,  (sec 
Safety  Cage  ;)  iron  ropes,  for  siiip-rigging,  for  engine-springs,  station  buffers,  and  pow- 
erful draw-springs.  Eaton's  main  idea  is  the  use  of  lamina?  of  Indian-rubber,  of  a  maxi- 
mum thickness  of  i  an  inch,  with  dividing  plates,  as  in  Lacey's  and  Fuller's,  which  avoids 
the  objections  stated  above,  by  supporting  the  Indian-rubber  at  smaller  intervals ;  for 
springs,  where  great  power  is  wanted  in  httle  compass,  and  to  act  through  short  dis- 
tances,— as  in  engine  bearing-springs,  lifting  springs,  and  some  kinds  of  draw-springs, — 
this  form  proves  to  be  well  suited.  We  give  below  the  result  of  one  such  spring  of  the 
following  dimensions  :  tlie  spring  was  built  up  of  2i  laminae,  -^  of  an  inch  thick,  4^  inches 
square,  with  a  thin  iron  plate  between  each,  and  a  hole  of  one  inch  diameter  for  the  guide 
rod  through  all ;  this,  and  several  of  the  other  experiments  were  made  in  a  press  of  great 
delicacy  and  power,  constructed  for  Messrs.  Geo.  Spencer  and  Co.,  for  the  purpose  of 
testing  such  springs,  at  their  ofiBce,  in  Cannon  Street  West,  London,  (see  Proving 
Machines.) 

Experiment. 

Length  including  plates. 
Tons.                                                                              Area  of  spring,  19  square  inches. 
0 87.6 

10        .       -       - 75 

2-0 -TVis 

3-0 VU, 

4-0 6i 

5-0 6f 

6-0 6f 

"^-O 6i 

8-0 6| 

90 6| 

10-0 6| 

Hodge's  compound  spring  (Xo.  13)  is  designed  to  obviate  the  frequent  breakage  of  the 
steel  springs  on  locomotive  engines.    Fig.  145  shows  one  of  these  springs ;  a  block  of 


145 


Indian-rubber  is  placed  on  each  end  of  the  steel  spring,  or  is  suspended  under  the  engine 
frame ;  they  are  in  use  on  several  of  the  English  railways,  and  are  said  to  answer  the 
purpose  intended  well. 

Scott's  patent  {see  Jig.  146  ;  and  list,  Xo.  14)  consists  in  the  use  of  blocks  of  Indian- 
rubber,  or  cones,  placed  over  the  centre  of  spring ;  they  are  to  obviate  the  danger  of 
overloading  carriages  and  trucks,  a  frequent  source  of  danger  to  the  springs,  and  are 
made  to  take  the  whole  load  in  case  of  a  spring  breaking :  they  are  in  use  on  the  Brighton 
and  Crystal  Palace  Railway,  Eastern  Counties,  Bombay  and  Baroda,  and  others.  The 
same  patentee  has  several  ingenious  applications  of  Indian-rubber  to  carriages  to  wheel 
tires,  to  the  bosses  of  wheels,  to  shackle  pins,  and  to  the  axle. 

Brulffes'  Patent. — (See  list.  No.  30,^1^.  147.)  This  inventor  proposes  to  use  Spencer's 
cones  in  blocks  of  wood,  instead  of  iron  confining  rings.  A  series  of  them  are  enclosed 
in  a  case  formed  in  the  side  timbers  of  the  underframe  of  the  railway  truck  or  carriage ; 
the  cup  space  is  formed  in  the  block  of  wood,  as  our  figure  shows,  and  no  guide  rods  are 


CAOUTCHOUC. 
146 


299 


required :  the  same  principle  is  applied  to  draw  and  bearing  springs.  The  advantages 
proposed  by  this  arrangement  are,  the  dispensing  with  guide  rods  and  the  taking  the  ulti- 
mate blow  on  blocks  of  wood,  which  deadens  its  effect ;  they  are  said  to  answer  very 
well,  and  are  used  almost  exclusively  on  the  South  Western  and  Bristol  and  Exeter  Rail- 
ways. 

14Y 


In  1847,  Mr.  De  Bergue  patented  some  improvements  in  the  application  of  Fuller's 
spring  to  buffer,  bearing,  and  draw  springs  for  railway  uses. 

Mr.  Fuller'^  Patent. — The  applications  for  common  road  carriages,  patented  by  Mr. 
Fuller  of  Buckjersbury  in  1852  and  1855,  have  been  extensively  used,  both  in  the  form 
of  cylindrical  rings  acting  by  compression  and  also  of  suspension  springs  for  lighter  kinds 
of  vehicles. 

Respecting  these  springs, /^s.  148,  149,  we  have  been  furnished  by  the  patentee  with 
the  following  particulars  : — 

The  form  generally  used  for  heavy  purposes,  such  as  drays,  vans,  wagons,  &c.,  con- 
sists of  a  series  of  rings  of  cylindrical  or  circular  form,  working  on  a  perpendicular  rod 
or  spindle,  on  each  side  the  axle,  with  the  usual  separating  plates  or  washers ;  the  depth 
and  diameter  of  the  rings  being  regulated  by  the  weight  to  be  sustained  and  the  speed 
required. 

During  the  late  war,  these  springs  were  introduced  by  Mr.  Fuller  to  the  notice  of  t!)e 
Government  authorities  at  the  Royal  Arsenal,  Woolwich,  and  were  in  consequence  ex- 
tensively adopted  for  all  kinds  of  military  carriages,  store  wagons,  ammunition  wagons, 
&c.  Tlicy  arc  also  applied  in  the  suspensory  form  for  the  medical  cars  and  ambulance 
wagons  for  the  wounded,  for  which  purposes  the  use  of  Indian-rubber  on  the  principle 
of  extension  is  found  to  produce  the  easiest  and  most  satisfactory  spring  hitherto  dis- 
covered. 

When  the  material  is  used  as  a  suspension  spring,  the  most  advantageous  form  for  the 
purpose  is  found  to  be  round  cord  of  the  best  and  purest  quality,  prepared  by  solvents, 
and  about  i  or  f  inch  diameter. 

A  continuous  length  of  such  cord  is  wound  at  a  considerable  tension  over  the  ends  of 
two  metal  sockets  or  rollers,  in  shape  something  resembling  a  cotton  reel,  and  whilst  in  a 


800 


CAOUTCHOUC. 


state  of  tension,  bound  at  each  end  with  strong  tape  or  other  suitable  binding;  the  num- 
ber of  cords  composing  the  spring,  varying  from  10  to  20,  30,  or  40,  accordin"-  to  the 
strength  required. 

148  149 


Another  important  adaptation  of  Indian-rubber  by  Mr.  Fidlcr,  is  tliat  of  anchor 
springs,  towing  ropes,  and  spiings  for  the  recoil  of  guns  and  mortars. 

During  the  Russian  war,  about  TJO  mortar  boats  were  constructed  of  light  draught, 
each  carrying  a  13-inch  mortar  on  a  revolving  pivot  and  platform  in  the  centre  of  deck. 
It  was  considered  desirable,  if  possible,  to  diminish  the  shock  produced  by  the  tremen- 
dous recoil  of  such  heavy  artillery  on  the  deck  of  small  vessels,  and  after  a  series  of 
trials  at  Shoeburyness,  which  proved  perfectly  satisfactory,  the  plan  was  adopted  of  mount- 
ing each  platform  upon  twenty  powerful  rings  of  Indian-rubber,  the  united  force  of  which, 
at  1-inch  deflexion,  would  resist  about  400  tons.  The  performance  of  these  mortar  ves- 
sels at  Sweaborg,  the  Black  Sea,  and  also  subsequently  in  China,  has  been  highly  satisfac- 
tory ;  the  intervention  of  this  elastic  material  being  found  effectually  to  preserve  the 
timbers  of  the  vessel. 

^  The  application  to  towing  ropes  and  anchor  cables,  has  not  yet  been  tried  to  an  ex- 
tent sufficient  to  test  its  merits;  but  it  is  universally  admitted  by  engineers  and  practical 
men,  that  a  powerfid  spring  adapted  to  the  chain  cables  of  vessels  when  riding  at  anchor 
(acting  on  the  principle  of  the  buffer  and  draw-springs)  would  often  prove  of  invaluable 
service  in  preventing  the  parting  of  the  cable  and  its  disastrous  results. 

In  the  list  of  patents,  we  have  indicated  the  nature  of  several  other  improvements, 
which,  being  merely  variations  of  the  more  important  ones,  we  do  not  dwell  on  here. 

Support  for  railicny  chairs. — Several  proposals  have  been  devised  to  this  end,  and  a 
number  of  plans  are  given  in  Coleman  s  patent,  1852.  He  places  the  Indian-rubber  under 
the  chair,  between  the  chair  and  rail,  between  the  rail  and  sleeper.  The  plan  has  been 
only  partially  tried,  but  the  proposer  is  very  sanguine  that  the  plan  will  prove  useful. 

Wheel  iires. — Fig.  150  shows  an  important  application  to  the 
tires  of  wheels  for  railway  purposes.  A  thin  band  of  Indian-rubber 
is  inserted  between  the  tire  and  spoke  ring,  by  first  covering  it  with 
a  thin  plate  of  iron,  to  protect  the  Indian-rubber  while  the  hot  tire 
is  put  on,  when  the  wheel  is  instantly  thrown  into  water  and  cooled. 
This  has  been  severely  tested  for  some  time,  and  found  to  answer 
very  well;  the  advantage  gained,  is  the  saving  in  the  breaking  and 
wear  of  the  tires. 

For  wi7idou'S. — Small  ropes  of  Indian-rubber  are  inserted  in 
grooves  at  each  side  of  the  window,  and  so  stop  out  draught  and 
prevent  noise. 

For  steam-hammer  beds. — A  plate  of  Indian-rubber  |-  thick,  is 
placed  under  the  bed  of  the  hammer;  the  effect  is  greatly  to  diminish  the  transmission 
of  shocks  to  the  building,  and  to  cheapen  the  foundation  :  as  an  instance  of  useful  appli- 
cation, we  may  state,  that  at  Messrs.  Ransome  and  May's  works,  at  Ipswich,  the  working 
of  the  steam-hammer  shook  the  building  and  windows  to  an  alarming  extent;  but  the 
insertion  of  blocks  of  vulcanized  rubber  under  the  anvil,  almost  entirely  obviated  these 
effects. 

Joints  between  engines  and  tenders. — Messrs.  Lund,  Spencer,  and  Fenton  have  also 

151 


150 


CAOUTCHOUC. 


501 


introduced  the  use  of  rings  of  this  material  to  form  a  joint  between  the  locomotive  and 
tender,  {fi(i.  151.)  They  are  extensively  used,  and  entirely  prevent  the  leakage  common 
to  the  old  ball  and  socket  joints,  and  are  much  cheaper  in  first  co.st.  Rings  of  Indian- 
rubber  were  proposed  by  Mr.  Wicksteud,  for  closing  the  socket  joint  of  water  pipes,  and 
they  are  used  in  a  variety  of  forms  for  that  purpose. 

Messrs.  W.  B.  Adams,  NormanvUle,  Wrighton,  and  Hodge  have  also  introdvjced  the 
use  of  shields  and  rings  of  Indian-rubber  for  keeping  tlie  backs  of  axle  boxes  tight,  so  as  to 
prevent  the  escape  of  the  grease  or  oil,  or  the  entry  of  dust  and  dirt. 

A  large  trade  has  been  established  in  the  supply  of  bands  of  Indian-rubber  for  driving 
machinery  ;  for  many  purposes  they  answer  better  than  leather,  water  having  no  effect  on 
them  and  there  being  little  or  no  slip  and  fewer  joints,  they  are  made  in  all  widths,  and  belts 
costing  £150  each  have  been  used  in  some  cases.  They  are  made  with  two  or  more  layers 
of  thread  cloth  between,  and  outside  of  which  the  rubber  is  placed. 

As  valves  for  steam  and  water  pumps,  Indian-rubber  prepared  to  suit  the  use  is  also  much 
used  by  all  our  large  engine-makers. 

As  tubes  for  conveying  beer,  water,  and  acid,  Indian-rubber  is  also  found  to  answer  well, 
and  is  used  largely.  The  tubes  are  made  in  all  sizes  and  strengths,  and  the  best  are  made 
by  alternate  layers  of  cloth  and  Indian-rubber.  Very  good  tubes  are  also  imported  from 
America.  , 

Another  useful  application  of  this  material,  is  for  the  joints  of  steam  and  hot-water  pipes ; 
for  this  and  similar  purposes,  a  peculiar  compound,  known  as  Hodge's  compound,  is  used, 
(patent  No.  11.)  This  consists  in  the  mixture  of  cotton  fibre  with  the  rubber  used  for 
springs,  known  as  the  triple  compound. 

The  success  of  these  applications  depends,  of  course,  entirely  on  the  composition  being 
suitable  to  the  various  purposes  to  which  they  are  applied  ;  some  being  niade  to  resist  the 
effect  of  heat,  others  of  acids,  grease,  and  oils,  the  study  of  which  has  become  an  important 
element  in  the  commercial  adaptations  of  the  various  inventions  enumerated.  ' 

IV.    SoLARIZATION    OF    CaOUTCIIOUC. 

Singular  as  caoutchouc  is  in  its  properties  and  in  its  application,  it  is  probable  that, 
besides  the  mechanical  and  electrical  qualities  and  general  resistance  to  chemical  action,  it 
may  yet  be  found  to  have  other  modifications  peculiar  and  valuable.  The  practical  men 
most  conversant  with  this  substance,  and  deeply  involved  with  patents  and  successful  manufac- 
tures, record  their  conviction  of  the  influence  of  solar  light,  and  the  marked  distinctions 
supposed  to  exist  between  the  influence  of  solar  and  terrestrial  heat  upon  this  substance. 

Mr.  Hancock  says,  "  In  my  early  progress,  I  found  that  some  of  the  rubber  I  employed 
was  very  quickly  decomposed  when  exposed  to  the  sun  :  as  the  heat  was  never  more  than 
90°,  and  rubber  exposed  to  a  much  higher  temperature  was  not  injured  by  it,  I  suspected 
that  light  had  some  effect  in  producing  this  mischief.  To  ascertain  this,  I  cut  two  square 
pieces  from  a  piece  of  white  rubber ;  one  of  these  I  colored  black,  and  exposed  it  to  the 
sun's  rays  ;  in  a  short  time,  the  piece  which  had  been  left  white  wasted  away,  and  the  sharp 
angles  disappeared ;  it  seemed  like  the  shape  of  a  thin  piece  of  soap  after  use  ;  the  blackened 
piece  was  not  at  all  altered  or  aflected.  The  lesson  taught  me  by  this  experiment  was  of 
great  value  ever  after." 

Speaking  of  the  annoyances  and  failures  in  the  early  Macintosh  goods  by  heat,  grease, 
&c.,  Mr.  Hancock  says,  "  The  injurious  effect  of  the  sun's  rays  upon  thin  films  of  rubber  we 
discovered  and  provided  against  before  much  damage  accrued." 

Mr.  Goodyear  says,  "  In  anticipation  of  the  future,  as  relates  to  a  mode  of  treatment  in 
manufacture,  which,  though  lightly  esteemed  and  little  thought  of  now,  I  believe  will  be 
extensively  practised  hereafter,  I  feel  bound  to  make  a  strong  though  qualified  claim  to  the 
process  of  solarization.  This  process  consists  in  exposing  caoutchouc,  when  combined  with 
sulphur,  to  the  sun's  rays."  Again,  "  When  exposed  to  the  sun's  rays  for  several  hours,  a 
change  is  produced,  which  may  be  called  natural  vulcanization,  in  all  thin  fabrics  or  thin 
sheets  of  caoutchouc."  "  Solarization  is  an  effectual  and  cheap  process  of  curing  Indian- 
rubber."  He  further  says,  "  It  is  well  cstal)lished  tliat  Indian-rubber  melted  at  about  200°, 
and  in  the  sun's  rays  at  100'  or  less.  Another  effect  yet  more  remarkable  in  the  treatment 
of  gum  elastic,  is  that  of  the  sun's  rays  upon  it :  when  combined  with  sulphur  and  exposed  to 
tlie  sun,  either  in  hot  weather  or  cold,  it  becomes  solarized,  or  divested  of  its  adiicsivc  qual- 
ity ;  whereas,  no  other  kind  of  light  or  heat  has  any  similar  effect,  until  the  high  de.;ree  of 
heat  is  applied  to  it,  about  270",  which  is  used  in  vulcanizing." — Goodyear,  p.  114,  vol.  I. 
New  Haven,  U.  S. 

V.  Trade  Applications  of  Vulcanized  Ixdian-Rcbbkr. 

Macintosh  and  Hancock  give  the  following  descriptions  of  their  trade  qualit}',  to  guide 
practical  men  ;  other  manufacturers  may  also  have  similar  scales  of  rubber. 

A  quality  is  the  most  clastic,  it  weighs  about  00  lbs.  per  cubic  foot,  or  Vae  of  a  lb.  per 


302 


CAPILLAIEE. 


culjic  inch,  (this  is  understood  to  mean  pure  sulphur  and  caoutchouc,  all  other  qualities  are 
mixtures.) 

D  quality  weighs  82  lbs.  per  cubic  foot,  or  '/ji  of  a  lb.  to  1  cubic  inch. 

E  quality,  more  elastic  than  D,  weighs  about  92  lbs,  to  the  cubic  foot,  or  '/le  of  a  lb.  to  1 
cubic  inch. 

F.  c.  Fibrou?  compound,  used  for  flange  washers,  valves,  and  pump-buckets,  weight  Vas 
of  a  lb.  per  cubic  inch. 

Many  applications  of  caoutchouc  can  only  be  named.  Surgical  apparatus,  and  remedial 
adaptations  for  hospital  purposes,  would  alone  occupy  great  space  ;  to  call  attention  to  the 
various  ingenious  contrivances,  other  information  and  specialities  may  be  referred  to  the 
heads  of  Indian-rubber  and  vulcanite,  or  hard  rubber,  vulcanization,  hose-pipes,  pontoons, 
life-preserving  apparatus,  shoes,  water-proof  fabrics,  washers  for  joints,  valves  for  engines 
and  pumps,  elastic,  endless,  and  driving  bands.  For  hot  and  cold  water  valves  this  sub- 
stance has  been  one  of  the  most  valuable  applications  to  ocean  steamers  for  many  years. 

The  old  mode  of  thread-making  is  now  entirely  obsolete,  having  given  way  to  a  new  one 
rendered  necessary  by  the  introduction  of  vulcanized  Indian-rubber,  which  now,  for  the 
purpose  of  thread-cutting,  is  always  produced  in  the  sheet  by  the  spreading  process  before 
described,  and  of  a  thickness  exactly  agreeing  with  the  widths  of  the  thread  to  be  cut ;  that 
is,  if  No.  28 '•be  required,  which  means,  if  28  of  the  threads  were  spread  side  by  side  they 
would  measure  one  inch ;  then  the  sheet  is  spread  Vse  of  an  inch  in  thickness,  and  conse- 
quently when  28  are  cut  out  of  the  inch,  square  threads,  i.  e.  threads  with  a  rectangular 
section,  arc  produced.  The  sheets  are  wound  upon  rollers,  which  are  then  fixed  on  centres 
in  the  lathe,  and  by  means  of  a  slide  rest  and  a  suitable  knife,  slices  of  the  sheet  are  cut  off, 
varying  in  thickness  from  '/ic  of  an  inch  to  Vto  of  an  inch  ;  and  one  of  the  greatest  advan- 
tages of  the  vulcanized  thread  is  the  great  length  that  can  be  cut ;  from  a  sheet  of  rubber 
wound  upon  a  roller,  hundreds  of  feet  or  yards  may  be  cut  at  once  into  one  continuous 
thread,  whereas  from  the  bottles  the  lengths  were  short,  had  to  be  joined,  and  diifered  in 
quality  from  each  other. 

Vulcanized  thread  is  covered  with  silk  and  cotton  ;  both  are  wound  round  it ;  the  vul- 
canized thread  is  considerably  more  elastic  than  the  native  thread  cut  from  bottles  or  sheets. 
Belts  and  bandages  made  from  the  vulcanized  thread  are  very  superior  to  the  old  sort,  now 
completely  obsolete. 

The  vulcanized  rubber  thread  has  lately  been  introduced  into  the  Jacquard  loom,  by 
Messrs.  Bonnet  and  Co.,  Manchester ;  the  thread  used  is,  by  its  elastic  force,  to  supersede 
the  use  of  the  weights  commonly  employed,  the  number  of  which  sometimes  amounts  to 
from  two  to  three  thousand  in  one  loonx. 

In  preceding  editions,  the  names  of  Hancock  and  Goodyear  were  scarcely  mentioned,  yet 
for  thirty-six  years  Mr.  Hancock  has  labored  to  make  a  manufacture.  For  many  years 
Messrs.  Hancock  and  Macintosli  were  alone  in  the  trade,  indeed  until  Macintosh's  patent 
ceased,  when  the  trade  widened.  His  first  patent  was  dated  1820,  and  the  masticating 
machine  was  the  foundation  of  the  manufacture.  Mr.  Goodyear  had  his  attention  drawn  to 
the  subject  by  the  manufacture  of  gum  elastic  in  the  United  States,  about  1831-2.  Both 
have  contributed  to  the  literature  of  the  art,  (mingled  with  personal  narratives,  and  trade 
affairs,)  and  it  is  presumed  that,  had  the  late  Dr.  Ure  had  their  practical  works  before  him, 
eulogistic  mention  would  have  been  offered  for  past  neglect.*  Both  gentlemen's  patents 
are  being  worked  by  other  men,  and  of  the  value  of  their  processes,  and  the  trade,  some 
idea  may  be  entertained  when  "  The  Scientific  American  "  recently,  while  opposing  the  re- 
newal of  the  terms  for  certain  patents  about  to  expire,  gives  the  estimate  of  worth  at 
2,000,000  dollars  for  Chauffee's  patents,  and  Goodyear's  several  patents  are  set  at  20,000,- 
000  dollars.  It  is  probal)le  that  the  trade  was  not  a  really  profitable  one  in  America  until 
about  1850.  Of  the  value  of  the  works  in  England  and  France  of  caoutchouc  applications 
no  aileriuate  data  appear.  Of  the  facts  involved  in  some  of  these  patents,  we  may  quote 
Mr.  Hancock's  words,  p.  106:  "I  think  I  might  venture  to  state,  not  boastfully,  but  as  a 
matter  of  fact,  that  there  is  not  to  this  day,  1856,  any  document  extant,  (including  those 
referred  to  in  it,)  which  contains  so  much  information  upon  the  manuf\icture  and  vulcaniza- 
tion of  rubber,  as  is  contained  in  this  specification.  If  any  of  my  readers,"  he  goes  on  to 
sav,  "  can  point  out  such  a  document,  I  shall  feel  obliged  if  they  will  inform  me  of  it."  This 
is  the  patent  of  1843. 

CAPILLAIRE.  Originally  a  kind  of  syrup,  extracted  from  maiden-hair.  The  term  is 
now  applied  to  a  finely  clarified  simple  syrup,  which  is  made  chiefly  with  orange-flower 
water. 

CAPNOMORE.     (C^°H"0'[?].)    One  of  the  substances  discovered  by  Keichcnbach  in 

*  Porson.il  Narrative  of  tlio  Origin  jind  Prnjrrpss  of  Caoutchouc  or  Indian-Eubber  manufactured  in 
England,  by  Thomas  Il.ancook.     London,  IsriT:  Lonsn^an  and  Co.,  8vo.  pp.  2S3,  (plates.) 

Gum  Einstic  and  its  Varieties,  with  a  detailed  Account  of  its  Applications  and  Uses,  and  of  the  Pis- 
coverv  of  Vnleanization;  by  Charles  Goodyear.  New  Haven,  U.  S.  Published  for  the  Author,  185.3,  2 
vols.  Svo.  pp.  246,  379,  (plates.) 


CARBOLIO  ACID.  303 

wood-tar.  It  appears  to  be  a  product  of  the  metamorphosis  of  creosote  under  the  influence 
of  heat,  or  of  the  alkalies  or  alkaline  earths.  It  has  not  been  sufficiently  examined  to  allovr 
of  its  formula  being  considered  as  established.  The  above  formula  is  founded  on  the  anal- 
ysis of  M.  Voelckel.  When  those  oils  from  wood-tar  which  are  heavier  than  water  are 
treated  with  a  strong  potash  lye,  creosote  and  capnomore  dissolve.  Pure  capnomore  is  not 
soluble  in  potash,  but  it  appears  to  dissolve  owing  to  the  presence  of  creosote.  When  the 
alkaline  solution  is  distilled,  the  capnomore  comes  over.  (Voelckel.)  It  is  more  probable 
that  the  capnomore,  instead  of  dissolving  under  the  influence  of  the  creosote,  and  subse- 
quently distilling  over  with  the  water,  is,  in  fact,  produced  by  a  decomposition  of  the  creo- 
sote, for  I  have  found  that  if  the  latter  be  long  boiled  with  potash  lye,  it  gradually  diminishes 
in  quantity,  and  finally  almost  disappears. 

The  density  of  capnomore  is  0-995.  It  boils  between  350"  and  400°.  This  variation 
of  the  boiling  point  is  indicative  of  a  mixture. — C.  G.  W. 

CAPRYLAMINE.  (C'^H'^N.)  A  volatile  base  obtained  by  Squire,  and  also  by  Cahours, 
by  acting  on  ammonia  with  iodide  of  capryle.  It  is  homologous  with  methylamine,  &c. — 
C.  G.  W. 

CAPUT  MORTUUM,  literally,  dead  matter ;  a  term  employed  by  the  alchemists  to  ex- 
press the  residuum  of  distillation  or  sublimation,  the  volatile  portions  having  been  driven 
off. 

CARAMEL.  Burnt  or  dried  sugar,  used  for  coloring  spirits  and  gravies.  It  is  a  black, 
porous,  shining  substance,  soluble  in  water,  to  which  it  imparts  a  fine  dark-brown  color. 
The  French  are  in  the  habit  of  dissolving  the  sugar,  after  it  has  been  exposed  for  some  time 
to  a  temperature  sufficiently  high  to  produce  the  proper  color,  in  lime-water ;  this  is  sold 
under  the  name  of  "  coloring." 

CARAT.  The  term  carat  is  said  to  be  derived  from  the  name  of  a  bean,  the  produce 
of  a  species  oi  eri/thlna,  a  native  of  the  district  of  Shangallas  in  Africa,  a  famous  gold  dust 
mart.  The  tree  is  called  kuara,  a  word  signifying  sun  in  the  language  of  the  country,  be- 
cause it  bears  flowers  and  fruits  of  a  flame  color.  As  the  dry  seeds  of  this  pod  are  always 
of  nearly  uniform  weight,  the  savages  have  used  them  from  time  immemorial  to  weigh  gold. 
The  beans  were  transported  into  India  at  an  ancient  period,  and  have  been  long  employed 
there  for  weighing  diamonds.  The  carat  of  the  civilized  world  is,  however,  an  imaginary 
weight,  consisting  of  four  nominal  grains,  a  little  lighter  than  four  grains  troy,  {poids  ds 
marc.)     It  requires  74  carat  grains  and  '/le  to  equipoise  72  of  the  other. 

It  is  stated  that  the  karat,  a  weight  used  in  Mecca,  was  borrowed  from  the  Greeks,  and 
was  equal  to  the  24th  of  a  denarius  or  denier. 

The  Encyclopedists  thus  explain  the  carat : — "  The  weight  that  expresses  the  fineness 
of  gold.  The  whole  mass  of  gold  is  divided  into  24  parts,  and  as  many  24th  parts  as  it  con- 
tains of  pure  gold  it  is  called  gold  of  so  many  carats.  Thus,  gold  of  twenty-two  parts  of 
pure  metal  is  gold  of  twenty-two  carats.  The  carat  of  Great  Britain  is  divided  into  four 
grains;  among  the  Germans  into  12  parts;  and  among  the  French  into  32."  Among  as- 
sayers,  even  in  this  country,  the  German  division  of  the  cai'at  is  becoming  common. 

CARBOLIC  ACID.  (C'^H^'O^  Syn.  Phenic  Acid,  Phenole,  Fhcnylic  Alcohol,  Ify- 
drate  of  Plicnyle.)  The  less  volatile  portion  of  the  fluids  produced  by  distillation  of  coal 
tar  contain  considerable  quantities  of  this  substance.  It  may  be  extracted  by  agitation  of 
the  coal  oils  (boiling  between  300°  and  400°)  with  an  alkaline  solution.  The  latter,  separated 
from  the  undissolved  portion,  contains  the  carbolic  acid  in  the  state  of  carbolate  of  the  al- 
kali. On  addition  of  a  mineral  acid,  the  phenole  is  liberated,  and  rises  to  the  surface  in  the 
form  of  an  oil.  To  obtain  it  dry,  recourse  must  bo  had  to  digestion  with  chloride  of  cal- 
cium, followed  by  a  new  rectification.  If  required  pure,  only  that  portion  must  be  received 
which  boils  at  370°.  If,  instead  of  extracting  the  carbolic  acid  from  coal  products  boiling 
between  300°  and  400°,  a  portion  be  selected  distilling  between  400°  and  428',  and  the 
same  treatment  as  before  be  adopted,  the  acid  which  passes  over  between  347°  and  319' 
will  consist,  not  of  carbolic  acid,  but  of  its  homologue,  cresylic  acid,  C"II''0-.  Commercial 
carbolic  acid  is  generally  very  impure.  Some  specimens  do  not  contain  more  than  50  per 
cent,  of  acids  soluble  in  strong  solution  of  potasli.  The  insoluble  portion  contains  naph- 
thaline, fluid  hydrocarbons,  and  small  portions  of  chinolhie  and  lepidine.  Car))olic  acid, 
when  very  pure  and  dry,  is  quite  .solid  and  colorless.  The  crystals  often  remain  solid  up  to 
95°,  but  a  trace  of  water  renders  them  fluid.  Its  specific  gravity  is  TOOS.  Carl)()lic  acid, 
when  mixed  with  lime  and  exposed  to  the  air,  yields  rosolie  acid.  Tlie  lime  acquires  a  rich 
red  color,  during  the  formation  of  the  acid.  No  means  of  dyeing  reds  permanently  with 
this  substance  have  yet  been  made  known.  Unfortunately,  the  red  tint  appears  to  require 
an  excess  of  l)asc  to  enable  it  to  exist,  consequently  the  carbolic  acid  of  the  air  destroys  tlie 
color.  {Dr.  Avr/us  Smith.)  I  find  tliat  homologues  of  carbolic  aci<l  exist,  which  boil  at  a 
temperature  beyond  the  range  of  the  mercurial  thermometer,  and  tliat  all  the  acids  above 
carbolic  aci<l  afford  rosolie  acid,  or  homologues  of  it,  when  treated  with  lime.  Creosote  of 
commerce  appears  to  consist  of  a  mixture  of  carbolic  and  cresylic  acids.  If  only  that  ])or- 
tion  be  received  which  distils  at  the  temperature  given  by  Reichenbach  as  the  boiling  point 


"~1 


304  CARBON. 

of  creosote,  it  will,  if  prepared  from  coal  oil,  consist  almost  entirely  of  cresylic  acid.  ( Wil- 
lianison  and  Fairlie.)  A  splinter  of  deal  wood,  if  dipped  first  in  carbolic  acid,  and  then  in 
moderately  strong  nitric  acid,  acquires  a  blue  tint.  For  a  comparison  of  the  properties  of 
Creosote  and  Carbolic  Acid,  see  Ckeosote. — C.  G.  W. 

CAKBOX.  {Equivalent  6  ;  hypothetical  density  of  vapor,  0-S290  ;  combining  measure 
one  volume.)  Carbon  exists  in  a  considerable  variety  of  forms,  most  of  which  are  so  unlike 
each  other,  that  it  is  not  surprising  the  older  chemists  should  have  believed  them  to  be 
compounds.  The  purest  variety  of  carbon  is  the  diamond.  The  latter  cry.stallizes  in  octo- 
hedrons  and  derived  forms.  The  diamond  does  not  owe  its  hardness  and  brilliancy  solely  to 
its  purity,  for  many  specimens  of  graphite  consist  of  carbon  as  free  from  admixture  as  the 
best  diamonds.  The  density  of  graphite  and  diamond,  however,  is  very  different ;  for  while 
the  former  seldom  exceeds  2"45,  and  is  often  much  lower,  the  diamond  is  very  constant, 
generally  ranging  between  3o0  and  3 '55.  Diamonds,  if  perfectly  transparent,  leave  scarcely 
any  residue  when  burnt  in  oxygen  gas.  If  not  clear,  they  yield  from  005  to  0'20  of  ash, 
consisting  chiefly  of  peroxide  of  iron,  but  also  containing  traces  of  silica.  The  refractive 
power  of  diamonds  is  as  high  as  2"439.  Sir  Isaac  Newton,  observing  that  oily  or  inflam- 
mable bodies  generally  possessed  the  greatest  refractive  powers,  inferred  from  the  high  in- 
dex of  refraction  of  the  diamond,  that  it  was  "an  unctuous  body  congealed."  This  idea 
will  appqar  the  more  happy,  when  it  is  considered  that  the  ashes  of  the  diamond  exhibit  a 
structure  resembling  that  of  vegetable  parenchyma.  In  freedom  from  ashes,  certain  graph- 
ites nearly  approach  the  diamond,  some  natural  varieties  not  yielding  more  than  0.33 
per  cent. 

Graphite. — This  kind  of  carbon  is  found  in  many  parts  of  the  world,  and  in  different 
degrees  of  purity ;  it  is  also  formed  artificially.  Some  native  varieties  are  exceedingly 
soft,  of  a  black  or  grayish  tint,  metallic  lustre,  and,  in  consequence  of  making  a  streak  on 
paper,  of  various  degrees  of  blackness,  according  to  the  mode  of  preparation  and  other 
circumstances,  are  invaluable  for  the  manufacture  of  artists'  pencils.     See  Plumbago. 

A  very  hard  graphite  is  found  lining  the  retorts  in  which  coal  gas  is  made  :  it  is,  when 
cut  into  plates  or  rods,  used  in  galvanic  arrangements,  either  for  the  poles  or  the  inactive 
elements  of  batteries. 

Coke. — This  variety  of  carbon  is  produced  by  the  distillation  of  pit-coal.  The  largest 
quantities  are  produced  in  the  manufacture  of  coal  gas.  It  of  course  varies  greatly  in  qual- 
ity with  the  coal  from  which  it  is  j)rocured.  The  density  of  coke  varies  not  only  with  the 
quality  of  the  coal,  but  also  with  the  greater  or  less  rapidity  of  the  firing,  and  the  duration 
of  the  operation.  From  1'2  to  1"4  is  a  not  uncommon  range  of  density  in  gas-cokes  toler- 
ably free  from  ash.  I  find  that  a  coke  of  the  density  1-223  will  have  its  specific  gravity 
raised  to  1-540,  if  the  air  in  the  interstices  be  removed  by  placing  it  in  water,  under  the  re- 
ceiver of  the  air-pump. 

Some  varieties  of  coke,  such  as  those  produced  in  the  manufacture  of  gas  from  bitu- 
minous shales  and  cannel  coals,  leave  an  aluminous  residue  almost  equal  in  bulk  to  the  coke 
itself. 

Anthracite  is  a  very  dense  natural  variety  of  carbon,  its  specific  gravity  varying  from 
1"390  to  1'7.  It  differs  considerably  in  quality,  some  kinds  being  almost  as  free  from  ex- 
traneous matters  as  graphite,  while  others  approach  nearer  to  the  nature  of  coals.  Thus, 
the  hydrogen  in  anthracite  oscillates  between  1*0  and  4-0.  Some  varieties  of  coal  have  only 
4-5  to  50  per  cent,  of  hydrogen,  thus  approximating  to  those  anthracites  which  have  high 
hydrogens. 

Charcoal. — There  are  several  varieties  of  charcoal :  among  them  may  be  mentioned 
those  from  wood,  bones,  and  the  peculiar  substance  found  between  the  layers  of  certain  pit 
coals,  and  known  as  mineral  charcoal.  Ordinary  charcoal  from  wood  contains  many  sub- 
stances besides  carbon,  among  which  may  be  mentioned  oxygen,  hydrogen,  traces  of  nitro- 
gen, and  ashes. 

Bone  charcoal  contains  a  large  quantity  of  earthy  phosphates  and  carbonates,  besides 
other  matters.  The  mineral  charcoal  is  merely  a  scientific  curiosity.  Charcoal  is  remark- 
able for  its  power  of  absorbing  and  oxidizing  animal  and  vegetable  coloring  matters,  also  for 
the  property  it  possesses  of  absorbing  gases.  The  bleaching  and  disinfecting  powers  of 
charcoal  appear  to  depend  chiefly  on  some  peculiarity  in  its  structure,  enabling  it  to  con- 
dense oxygen  in  a  manner  somewhat  rcsemljling  platinum  black. 

Animal  charcoal  is  used  as  a  bleaching  agent  in  the  form  of  coarse  grains :  when  once 
used,  it  may  be  partially  restored  to  activity  by  re-burning ;  but,  eventually,  it  becomes 
worthless  for  that  purpose,  and  is  then  only  fit  for  conversion  into  superphosphate  of  lime 
for  manure,  by  the  agency  of  sulphuric  acid.  Where  acid  solutions  are  to  be  decolorized 
by  animal  charcoal,  it  is  necessary  before  use  to  remove  the  earthy  phosphates,  &c.,  by 
digestion  with  hydrochloric  acid.  It  is  essential  that  the  purified  charcoal  should  Le 
washed  with  a  great  quantity  of  water,  in  order  to  remove  the  acid  and  the  salts  formed  by 
its  action.  Advantage  has  been  taken,  liy  Dr.  Stcnhouse,  of  the  absorbent  power  of  char- 
coal, in  order  to  prevent  danger  arising  from  putrid  or  offensive  vapors.     For  this  purpose 


CARBONATES. 


305 


he  has  contrived  a  charcoal  respirator,  which  fulfils  its  intended  office  with  remarkable  suc- 
cess.    See  Charcoal. 

For  a  description  of  the  method  of  preparing  the  variety  of  carbon  known  as  Lamp- 
Black,  see  Lamp-Black. 

The  description  of  the  charcoal  best  adapted  for  pyrotechnic  purposes  will  be  found  un- 
der the  head  Gunpowder. 

Carbon  combines  with  several  elements,  forming  in  general  well  marked  and  highly  im- 
portant substances.  Several  of  these  compounds  will  be  found  under  the  head  of  Carlsonic 
Acid. 

The  quantities  of  charcoal  yielded  by  various  kinds  of  wood  have  been  given  by  more 
than  one  experimenter ;  but  the  results  are  so  widely  different  that  no  great  value  can  be 
attached  to  them.  It  is  evident  that  tlie  most  extreme  care  would  be  required  in  selecting 
the  various  woods  and  preparing  them  for  anayisis,  if  results  were  desired  capable  of  being 
employed  as  standards  for  reference.  Charcoal  is  extremely  indestructible  under  ordinary 
circuuistances ;  it  is,  therefore,  usual  to  char  stakes  or  piles  of  wood  which  are  to  be  em- 
ployed for  supporting  buildings,  or  other  erections,  in  damp  situations. 

It  will  be  seen,  from  wliat  has  already  been  said,  that  absolutely  pure  carbon  is  scarcely 
to  be  met  with,  even  in  the  diamond.  In  determining  the  atomic  weight  of  carbon  by  com- 
bustion of  the  diamond  in  oxygen,  according  to  the  method  employed  by  MM.  Dumas  and 
Stas,  it  was  always  necessary  to  determine  and  allow  for  the  ashes  remaining  after  the  com- 
bustion. The  purest  charcoal  that  can  be  obtained  by  the  calcination  of  sugar  for  several 
hours  at  the  highest  temperature  of  a  powerful  blast  furnace,  contains  oxj'gen  and  hydro- 
gen, the  former  to  the  extent  of  about  \  per  cent.,  and  the  latter  0'2. 

Carbon,  on  uniting  with  sulphur,  forms  the  curious  fiEtid  volatile  fluid  known  as  bisul- 
phide or  sulphuret  of  carbon.  In  constitution  it  resembles  carbonic  acid,  and  it  may,  in 
fact,  be  considered  as  that  gas  in  whicli  the  oxygen  is  replaced  by  sulphur.  A  new  gas  lias 
been  recently  described  by  M.  Baudrimont,  bearing  the  same  relation  to  carbonic  oxide  that 
bisulphide  of  carbon  does  to  carbonic  acid:  its  formula,  therefore,  is  C  S. 

When  certain  hydrocarbons  are  treated  alternately  with  chlorine  and  alkalies,  substitu- 
tion compounds  are  formed,  in  wliich  the  hydrogen  in  the  original  substance  is  replaced  by 
chlorine  ;  thus  olefiant  gas  (C*H^),  by  this  mode  of  operating,  yields  C^Cl^  It  is  true  that 
tliis  formula  might  be  written,  for  simplicity's  sake,  CCl,  but  such  an  expression  would  be 
incorrect ;  because,  in  the  first  place,  it  would  not  indicate  its  relation  to  the  parent  sub- 
stance, and  in  the  next,  it  would  not  correspond  to  the,  at  present,  almost  universally  re- 
ceived axiom,  that  an  equivalent  of  an  organic  body  is  that  quantity  which  is  represented 
by  four  volumes  of  vapor. 

A  bromine  of  carbon  exists  ;  its  mode  of  formation  appears  to  be  of  a  somewhat  similar 
character  to  the  chlorine,  for  it  is  sometimes  found  in  commercial  bromine,  which  has  been 
prepared  with  the  agency  of  ether.  See  Bromine.  It  is  doubtless  formed  by  the  gradual 
replacement,  by  bromine,  of  the  hydrogen  in  the  ethyle. — C.  G.  W. 

CARBON,  BISULPHIDE  OF,  (formerly  Carburet  of  Sulphur  or  Sulphuret  of  Carbon,) 
also  called  by  the  elder  chemists  the  Alcohol  of  Sulphur  ;  a  limpid  volatile  liquid  possessing 
a  penetrating  fcetid  smell  and  an  acrid  burning  taste. 

Bisulphide  of  carbon  is  prepared  by  distilling,  in  a  porcelain  retort,  from  pyrites,  the  bi- 
sulphide (bisulphuret)  of  iron,  with  a  fourth  of  its  weiglit  of  well-dried  charcoal,  both  in  a 
state  of  fine  powder,  and  intimately  mixed.  The  vapor  from  the  retort  is  conducted  to  the 
bottom  of  a  bottle  filled  with  cold  water  to  condense  it.  The  equivalent  of  the  bisulphide 
of  carbon  is  38  ;  its  formula  CS'^ 

The  bisulphide  of  carbon  is  insoluble  in  w^ater,  but  it  is  soluble  in  alcohol.  It  dissolves 
sulphur,  phosphorus,  and  iodine.  The  solution  of  phosphorus  in  this  liquid  has  been  em- 
ployed for  electrotyping  very  delicate  objects,  such  as  grasses,  flowers,  feathers,  &e.  Any 
of  these  are  dipped  into  the  solution  :  by  a  short  exposure  in  the  air,  the  bisulphide  of  car- 
bon evaporates,  and  leaves  a  film  of  phosphorus  on  the  surfaces ;  they  are  then  dipped  into 
nitrate  of  silver,  by  which  silver  is  precipitated  in  an  exceedingly  minute  film,  upon  which, 
by  the  electrotype  process,  any  thickness  of  silver,  gold,  or  copper  can  be  deposited.  If  a 
few  drops  of  the  bisulphide  of  carbon  are  put  into  a  solution  of  the  cynnide  of  silver,  from 
which  the  metal  is  being  deposited  by  the  electrotyping  process,  it  covers  the  article  quite 
brightly,  whereas,  without  the  bisulphide,  the  precipitated  metal  would  be  dull.  See  Elec- 
tro-Metallurgy. 

CARBONATES.  By  this  term  is  understood  the  salts  formed  by  the  union  of  cariionie 
acid  with  bases. 

.  Tlie  carbonates  arc  among  the  most  valuableof  the  snlts,  whether  we  regard  their  ]ihysi- 
cal,  geological,  chemical,  or  technical  interest.  Were  limestone  and  marble  the  only  car- 
bonates familiarly  known,  they  would  be  sufficient  to  stamp  this  class  of  salts  as  among  the 
most  important.  The  carbonates  of  lime,  potash,  soda,  ammonia,  and  lend  are  articles  of 
immense  importance  to  the  technologist,  and  are  prepared  on  a  vast  scale  lor  variouii  pur- 
poses in  the  arts.  The  carbonates  of  iron  and  copper  are  the  most  valued  ones  of  those 
metals.  Numerous  processes  of  separation  in  analyses  arc  founded  on  the  various  degrees 
Vol.  III.— 20 


306 


OAKBUNCLE. 


of  solubility  in  water  and  certain  reagents  of  the  different  carbonates.  By  taking  advantage 
of  this  fact,  baryta,  strontia,  and  lime  may  be  separated  from  magnesia  and  the  alkalies. 
There  are  few  analytical  problems  which  have  attracted  more  attention  than  the  accurate 
determination  of  the  carbonic  acid  in  the  carbonates.  This  has  partly  arisen  from  the  fre- 
quency with  which  the  potashes,  soda  ashes,  limestone,  and  other  carbonates  of  commerce, 
are  sent  to  chemists  for  analysis.  The  number  of  instruments  contrived  for  the  purpose  is 
something  extraordinary,  especially  when  the  simplicity  and  ease  of  the  operation  are  con- 
sidered. Among  them  all,  there  is  none  more  convenient  or  easy  to  use  than  that  of  Par- 
nell.     "  It  consists  of  a  glass  flask  {Jig.  152)  of  about  two  ounces'  capacity,  fitted  with  a 


152 


sound  cork,  through  which  two  tubes  pass,  one 
serving  to  connect  a  chloride-of-calcium  tube  a, 
while  the  other,  6,  will  be  described  presently.  A 
small  test-tube,  c,  is  so  placed  in  the  flask,  and  is 
of  such  a  size,  that  it  cannot  fall  down,  but  its  con- 
tents may  be  made  to  flow  out  by  inclining  the 
apparatus  to  one  side.  To  perform  the  experi- 
ment, a  weighed  quantity  of  the  carbonate  is  placed 
in  the  flask,  and  water  added  up  to  the  level  seen 
in  the  figure  ;  the  test-tube  is  then  filled  nearly  to 
the  top  with  concentrated  sulphuric  acid,  and  is 
carefully  lowered  into  the  flask  ;  the  cork  with  the 
tubes  attached  is  then  affixed,  the  aperture  b  being 
closed  with  a  small  cork.  The  whole  apparatus  is 
now  carefully  weighed  ;  the  flask  is  then  to  be  in- 
clined so  as  to  allow  some  of  the  acid  to  flow  out, 
and,  when  the  effervescence  has  subsided,  a  little 
more,  and  so  on,  until  no  more  carbonic  acid  is 
evolved.  The  flask  is  now  to  be  so  inclined  as  to 
cause  the  whole  of  the  acid  to  mingle  with  the 
aqueous  fluid,  and  thus  cause  a  considerable  rise  of  temperature  ;  this  expels  the  carbonic  acid 
from  the  liquid  ;  but  as  an  atmosphere  of  the  latter  gas  fills  the  flask,  it  must  be  removed  and 
replaced  by  air,  as  the  difference  in  density  of  the  two  is  very  considerable.  For  this  pur- 
pose, the  cork  b  is  removed  and  air  is  sucked  out  of  </,  until  it  no  longer  tastes  of  carbonic 
acid  ;  the  flask  is  then  allowed  to  become  perfectly  cold,  and,  the  little  cork  being  replaced, 
it  is  then  re-weighed  ;  the  difference  in  the  two  weiglrings  is  the  amount  of  carbonic  acid  in 
the  specimen.  On  drawing  air  for  some  time  through  the  apparatus,  it  begins  slowly  to  ac- 
quire weight,  arising  from  the  moisture  in  the  atmosphere  being  absorbed  by  the  chloride 
of  calcium,  and  although  the  error  introduced  by  this  means  is  too  minute  to  affect  ordinary 
experiment,  it  must  not  be  neglected  where,  from  the  quantity  of  material  in  the  flask  being 
limited,  or  other  causes,  a  small  difference  has  tin  important  bearing  on  the  result.  In  this 
latter  case  another  chloride-of-calcium  tube  is  to  be  attached  to  the  aperture  h,  and  the  air 
must  be  drawn  through  by  means  of  a  suction-tube  applied  at  d." — C.  G.  W.'s  Chemical 
Manipulation. 

The  commercial  value  of  the  carbonates  of  potash  and  soda  may  equally  well  be  deter- 
mined by  ascertaining  the  quantitv  of  dilute  sulphuric  acid  required  to  neutralize  them. — 
C.  G.  W. 

CARBUNCLE.  A  gem  much  prized  by  the  ancients,  and  in  high  repute  during  the 
middle  ages,  from  its  supposed  mysterious  power  of  emitting  light  in  the  dark.  Benvenuto 
Cellini  affirms,  in  his  treatise  on  jewellery,  that  he  had  seen  the  carbuncle  fjlouing  like  a 
coal  with  its  own  light. 

"  The  garnet  was,  in  part,  the  carbunculus  of  the  ancients,  a  term  probably  also  applied 
to  the  spinel  and  oriental  ruby.  The  Alabandic  carbuncles  of  Pliny  were  so  called  because 
cut  and  polished  at  Alabanda.  Hence  the  name  Almandine  now  in  use.  Pliny  describes 
vessels  of  the  capacity  of  a  pint  formed  from  carbuncles,  '  non  claros  ac  plerumque  sordidos 
ac  semper  fulgoris  horridi,'  devoid  of  lustre  and  beauty  of  color, — which  probably  were 
large  common  garnets." — Dnvn. 

CARBURETTED  HYDROGEN,  or  HYDROCARBON.  A  term  used  to  denote  those 
bodies  which  consist  of  carbon  and  hydrogen  only.  The  number  of  hydrocarbons  now 
known  is  very  great,  and  the  list  is  increasing  every  day.  They  were  very  little  understood 
until  lately,  but  so  much  has  now  been  done  that  the  anomalies  and  difficulties  attending 
their  history  are  rapidly  disappearing.  Although  the  number  of  individual  bodies  is,  as  has 
been  said,  very  considerable,  they  are  derived  from  a  few  great  families.     The  principal  are 


the  following : — 


Homologucs  of  Olefiant  gas. 

"  Methyle. 

"  Marsh  gas. 

"  Benzoic. 

"  Naphthaline. 

Isomers  of  Turpentine. 


CARBUKETTED  HYDROGEK 


307 


The  other  families  which  yield  hydrocarbon  derivatives  are  less  important  than  the  above, 
and  will  not  be  noticed  here. 

It  is  curious  that  the  destructive  distillation  of  organic  matters  is,  of  all  operations, 
tlie  most  fruitful  source  of  these  bodies.  Coal  yields  a  great  number,  the  nature  varying 
with  the  temperature.  When  ordinary  coals  are  distilled  at  very  high  temperatures,  as 
in  the  production  of  gas,  hydrocarbons  belonging  to  the  first  four  families  are  produced, 
and  also  a  considerable  quantity  of  naphthaline;  but  when,  on  the  other  hand,  they  are 
distilled  at  as  low  a  heat  as  is  compatible  with  their  thorough  decomposition,  they  yield 
fluid  hydrocarbons,  principally  belonging  to  the  first  two  classes,  accompanied,  however, 
by  a  considerable  quantity  of  paraffine.  The  homologues  of  olefiant  gas  have  acquired 
extreme  interest,  owing  to  the  brilliant  results  obtained  by  MM.  Berthelot,  and  De  Luca, 
by  Cahours,  and  Hofmann  in  the  study  of  their  derivatives.  Tiie  homologues  of  methyle 
have  attracted  considerable  attention,  in  consequence  of  the  successful  isolation,  by  MM. 
Franklaftd  and  Kolbc,  of  the  singular  gioup  of  hydrocarbons  known  as  the  organic  radi- 
cals, and  which,  until  then,  were  regarded  as  hypothetical  bodies,  existing  only  in  combi- 
nation. 

The  hydrocarbon  homologues  with  benzole  not  only  exist  in  considerable  quantity  in 
ordinary  coal  naphtha,  but  are  produced  in  a  great  variety  of  interesting  reactions. 
Those  at  present  known  are  contained  in  the  following  Table  : — 

Table  of  the  Physical  Properties  of  the  Benzole  Series. 


Name. 

Formula. 

Boiling 
Point. 

Specific 
Gravity. 

Specific  Gravity  of  Vapor. 

Benzole  -        -        -        - 
Toluole   .... 
Xylole     .... 
Cumole   .        .        .        • 
Cyraole   .... 

C'^H« 
C"H» 

C'^H'- 
C-°H" 

176° 

230 

259 

298 

347 

0-850 
0-870 

0-861 

Experiment. 

2-77 
3-26 

3-96 
4-05 

Theory. 
2-699 
3-183 
3  668 
4-150 
4-036 

Benzole  has  already  been  sufi5ciently  described,  and  will  not,  therefore,  be  further 
alluded  to.  All  these  hydrocarbons  yield  a  great  number  of  derivatives,  when  treated 
with  various  reagents.  By  first  treating  them  with  strong  nitric  acid,  so  as  to  obtain 
nitro-compounds,  that  is  to  say,  the  original  substance  in  which  an  equivalent  of  hydro- 
gen is  replaced  by  hyponitric  acid  (NO^),  strongly  odorous  oils  are  produced.  When 
treated  with  sulphide  of  ammonium  or  protacetate  of  iron,  these  oils  become  reduced,  and 
yield  a  very  interesting  series  of  volatile  organic  bases  or  alkaloids ;  these  are  aniline, 
toluidine,  xylidine,  cumidine,  and  cymidine.  Mr.  Barlow  has  shown  that  special  precau- 
tions are  necessary  in  converting  cymole  into  nitrocymole,  preparatory  to  the  formation 
of  the  alkaloid  cymidine.  Cymole  is  acted  on  too  violently  by  nitric  acid  to  allow  of  the 
nitro-compound,  being  formed,  unless  the  precaution  is  taken  of  cooling  the  acid  and  hy- 
drocarbon, by  means  of  a  freezing  mixture,  before  allowing  them  to -react  on  each  other. 
The  nitro-compound  when  well  formed,  may  be  reduced  in  the  ordinary  manner.  These 
alkalies  have  lately  acquired  special  importance  in  consequence  of  the  valuable  dyes  that 
Mr.  Perkins  has  succeeded  in  producing  from  them. 

Paraffine  is  a  solid  hydrocarbon  of  great  interest;  it  is  found  both  in  wood  and  coal 
tar.  When  coal  is  distilled  for  the  purpose  of  producing  gas,  the  temperature  is  so  liigh 
as  to  be  unfavorable  for  its  production,  and  consequoirtly  mere  traces  only  arc  found  in 
ordinary  coal  tar.  But  if  any  kind  of  coal  be  distilled  at  the  lowest  possiI)le  tempera- 
ture, not  only  is  the  resulting  naphtha  of  nuich  lower  density  than  that  produced  in  the 
ordinary  manner,  but  considerable  quantities  of  paraffine  are  found  in  the  distillate.  Tiie 
last-mentioned  substance  is  every  day  becoming  more  important,  iti  consequence  of  the 
valuable  illuminating  properties  that  have  been  found  to  belong  to  it.  Colorless,  inodor- 
ous, hard  at  all  moderate  temperatures,  it  forms  the  most  elegant  material  for  candles  yet 
discovered.     See  Paraffine. 

Modern  researches  have  shown  that  the  hydrocarbons  generally  are  formed  on  one 
type,  viz.,  hydrogen.  Assuming  hydrogen  in  the  free  state  to  be  a  double  molecule,  HII, 
the  hydrocarbons  are  formed  by  the  substitution  of  one  or  two  eciuivalents  of  a  positive 
or  negative  radical  for  one  or  two  of  the  equivalents  of  hydrogen ;  thus  methyle,  the 

formula  of  which  (for  four  volumes)  is  /^sria  or  C^H",  is  h)-drogen  in  which  both  equiva- 
lents arc  reflected  by  methyle.  Olefiant  gas  is  liydrogen  in  which  one  Cipiivalent  is  re- 
placed by  the  negative  radical  acetylo,  or  vinyle,  and  so  on. 

There  is  one  large  class  of  hydrocarbons  the  rational  formula;  for  which  are  not 
known,  and  which  will  probably  remain  in  this  condition  for  some  time.  We  allude  to 
the  numerous  essential  oils  isomeric  with  oil  of  turpentine.     Many  of  these  have  almost 


308 


CARMIN^E. 


the  same  boiling  point  and  precisely  the  same  vapor  density  as  their  type ;  but  in  odor, 
fluidity,  density  in  the  liquid  state,  and  various  other  minor  points,  are  essentially  diSer- 
cnt.     The  Ibllowing  Table  exhibits  some  of  their  physical  properties  : — 

Table  of  the  Physical  Properties  of  some  Isomers  of  Oil  of  Turpentine. 


Name. 

Formula. 

Boiling 
Point. 

Specific 
Gravity. 

Specific  Gravity  of  Vapor. 

Oil  of  turpentine     - 
"      athanianta     - 

322 
S25-4 

0-864 
0-843 

E.xperimont. 
4-764 

Theory. 

4-706 

do. 

"      bergauiot 

(.=0JJ10 

861-4 

0-869 

. 

do. 

"      bii'ch  tar 

Q:0|jir,, 

313-0 

0-847 

5-28 

do. 

Caoutchine     - 

C="ll'»? 

338-0 

0-842 

4-46 

•do. 

Oil  of  carui,  or  caruene  - 

c-nv^ 

343-4 

. 

. 

do. 

"      lemon  - 

C20JJ16 

343-4 

0-8514 

4-87 

do. 

"      copaiva 
"      cubebs 

473-0 
490.0 

0-878 
0-929 

- 

do. 
do. 

"      clemi    - 

psorj  IB 

345-2 

0-849 

. 

do. 

"     juniper 

C  =  U££.6 

320-0 

- 

. 

do. 

Terebric  oil  accompanving 

oil  of  gaultheria 

Qsogw 

320-0 

. 

4-92 

do. 

Terebric  oil  in  clove  oil     - 

C-'H's 

483-8 

0-9016 

. 

do. 

"         "       pepper 

"         "        balsam  of  tolu 

332-0 
320-0 

0-864 
0-837 

4-73 

do. 
do. 

"         "       oil  of  valerian 

(jiojjio 

320-0 

- 

4-60 

do. 

An  inspection  of  the  above  Table  will  show  that  while,  beyond  doubt,  a  great  number 
of  essential  oils  are  truly  isomeric  with  turpentine,  there  are  some  the  constitution  of 
which  is  by  no  means  well  established.  The  oil  of  birch  tar  (used  for  preparing  Russia 
leather)  and  caoutchine  are  by  no  means  sufficiently  investigated.  The  latter  is  being 
studied  afresh  by  the  author  of  this  article. 

The  above  account  of  some  of  the  more  prominent  hydrocarbons  is  necessarily  brief 
and  imperfect;  partly  because  the  limits  of  this  work  preclude  the  possibility  of  entering 
minutely  into  the  details  of  their  history,  and  partly  because  many  of  them  are  described 
at  greater  length  in  other  articles,  especially  under  Naphtha. — C.  G.  W. 

CARMINE.  {Carmin,  Fr.  ;  Karminstoff,  Germ.)  The  coloring  matter  of  the  cochi- 
neal insect.     See  Cochineal. 

There  are  several  methods  of  preparing  carmine,  the  following  being  the  most  ap- 
proved : — 

Dr.  Pereira  speaks  highly  of  this  process.  A  decoction  of  the  black  cochineal  is 
made  in  water ;  the  residue,  called  carmine  ffromids,  is  used  by  paper-stainers.  To  the 
decoction  is  added  a  precipitant,  usually  bichloride  of  tin.  The  decoction  to  which  the 
bichloride  of  tin  has  been  added  is  put  into  a  shallow  vessel  and  allowed  to  rest.  Slowly 
a  ileposit  takes  jilace,  which  adheres  to  the  sides  of  the  vessel,  and  the  liquid  being  poured 
off,  it  is  dried  :  this  precipitate  is  carmine.  The  liquid,  when  concentrated,  is  called 
Ihjiiid  roHijc. 

Carmine  is,  according  to  Pelletier  and  Caventou,  a  triple  compound  of  the  coloring 
substance  and  an  animal  matter  contained  in  cochineal,  combined  with  an  acid  added  to 
effect  the  precipitation.  The  most  successful  investigator  into  the  coloring  matter  of  the 
cochineal  has  been  llr.  Warren  de  la  Rue.  This  chemist  had  the  opportunity  of  submit- 
ting the  living  insect  to  Tnicroscopical  examination.  lie  found  it  to  be  covered  with  a 
white  dust,  which  was  likewise  observed  on  the  adjacent  parts  of  the  cactus  leaves  on 
which  the  animal  feeds.  This  dust,  which  he  considered  to  be  the  excrement  of  the  ani- 
mal, has,  under  the  nTuTOscope,  the  ap)icarance  of  white  curved  cylinders  of  a  very  uni- 
form diameter.  On  removing  the  powder  wilh  ethei-,  and  piercing  the  side  of  the  insect, 
a  purplish-red  fluid  exudes,  which  contains  red  coloring  matter,  in  minute  granules  assem- 
bled round  a  colorless  nucleus.  These  groups  seem  to  float  in  a  colorless  fluid,  which 
appears  to  prove,  that  whatever  may  be  the  function  of  the  coloring  matter,  it  has  a  dis- 
tinct and  marked  ibrm,  and  does  not  pervade,  as  a  mere  tint,  the  fluid  portion  of  the 
insect.  To  this  coloring  matter,  Mr.  De  la  Rue  has  given  the  name  of  Carminic  Acid, 
which  sec. 

There  are  some  remarkable  peculiarities  about  the  production  of  carmine:  the  shade 
and  character  of  the  color  are  altered  by  slight,  very  slight,  differences  of  the  tempera- 
ture at  which  it  is  prepared  ;  and  wilh  every  variation  in  the  circumstances  of  illumina- 
tion, a  change  is  discovered  in  the  color.  Sir  H.  Davy  relates  the  following  anecdote  in 
illustration  of  this  : — 


OARKELIAN. 


309 


"A  manufacturer  of  carmine,  who  was  aware  of  the  superiority  of  the  French  color, 
went  to  Lyons  for  the  purpose  of  improving  liis  process,  and  bargained  with  a  celebrated 
manufacturer  in  that  city  for  the  acquisition  of  liis  secret,  for  which  he  was  to  pay  £1,000. 
lie  saw  all  the  process,  and  a  beautiful  color  was  produced,  but  he  found  not  the  least 
difference  in  the  French  method  and  that  wliicli  had  been  adopted  by  himself.  He  ap- 
pealed to  his  instructor,  and  insisted  that  he  must  have  kept  something  concealed.  The 
man  assured  him  that  he  had  not,  and  invited  him  to  inspect  the  process  a  second  time. 
He  very  minutely  examined  the  water  and  the  materials,  which  were  in  every  respect 
similar  to  his  own,  and  then,  very  much  surprised,  he  said  : — '  I  have  lost  both  my  money 
and  my  labor ;  for  tiie  air  of  England  does  not  admit  of  our  maiiiug  good  carmine.' — 
'Stav,'  said  the  Frenchman,  '  don't  deceive  yourself;  what  kind  of  weather  is  it  now  ?' — 
'  A  bright  suimy  day,'  replied  the  Englishman.  '  And  such  are  the  days,'  replied  the 
Frenchman,  'upon  which  I  make  my  colors;  were  I  to  attempt  to  manufacture  it  on  a 
dark  and  cloudy  day,  my  results  would  be  the  same  as  yours.  Let  me  advise  you  to 
make  your  carmine  on  sunny  days.'" 

Experiments  on  this  subject  have  proved  that  colored  precipitates  which  are  brilliant 
and  beautiful  when  they  are  precipitated  in  bright  sunshine,  are  dull,  and  suffer  in  their 
general  character,  if  precipitated  in  an  obscure  apartment,  or  in  the  dark. 

CARMINIC  ACID.  The  following  is  the  best  method  of  obtaining,  in  a  state  of 
purity,  the  coloring  principle  of  cochineal,  or  carminic  acid:  The  ground  cochineal  is 
boiled  for  about  twenty  minutes  with  fifty  times  its  weight  of  water ;  the  strained  decoc- 
tion, after  being  allowed  to  subside  for  a  quarter  of  an  hour,  is  decanted  off  and  precipi- 
tated with  a  solution  of  the  acetate  of  protoxide  of  lead,  acidulated  with  acetic  acid,  (1 
acid  to  6  of  the  salt.)  The  washed  precipitate  is  decomposed  by  hydrosulphuric  acid, 
{sulphuretted  hydroffcn,)  the  coloring  matter  precipitated  a  second  time  with  acidulated 
acetate  of  protoxide  of  lead,  and  decomposed  as  before.  The  solution  of  carminic  acid 
thus  obtained  is  evaporated  to  dryness,  dissolved  in  boiling  absolute  alcohol,  dissolved 
with  a  portion  of  carminate  of  protoxide  of  lead,  which  has  been  reserved,  (for  the  separ- 
ation of  the  phosphoric  acid,)  and  then  mixed  with  ether,  to  precipitate  a  small  portion 
of  nitrogenous  matter.  Tliis  filtrate  yields,  upon  evaporation  in  vacuo,  pure  carminic 
acid.  When  thus  prepared,  it  is  a  purple-brown  friable  mass,  transparent  when  viewed 
by  the  microscope,  and  pulverizable  to  a  fine  red  powder,  soluble  in  water  and  in  alcohol 
in  all  proportions,  and  very  slightly  soluble  in  ether,  which  does  not  however  precipitate 
it  from  its  alcohoHc  solution.  It  decomposes  at  temperatures  above  136°.  The  aqueous 
solution  has  a  feebly  acid  reaction,  and  does  not  absorb  oxygen  from  the  air;  alkalies 
change  its  color  to  purple ;  in  the  alcoholic  tincture,  they  produce  purple  precipitates  ; 
the  alkaline  earths  also  produce  purple  precipitates.  Alum  gives  with  the  acid  a  beautiful 
crimson  lake,  but  oidy  upon  the  addition  of  a  little  ammonia.  The  acetates  of  the  pro- 
toxides of  lead,  copper,  zinc,  and  silver  give  purple  precipitates;  the  latter  is  immediately 
decomposed  and  silver  deposited.  Protochloride  and  bichloride  of  tin  give  no  precipi- 
tates, but  change  the  color  to  a  deep  crimson. 

The  analyses  of  carminic  acid  led  to  the  formula  C-*'n"0"'.  The  compound  of  pro- 
toxide of  copper  appeared  to  be  the  only  salt  that  could  be  employed  with  any  certainty 
for  the  determination  of  the  atomic  weight,  as  the  other  salts  furnished  no  satisfjxctory 
results.  The  salt  of  copper  was  prepared  by  adding  cautiously  to  an  aqueous  solution  of 
carminic  acid,' acidulated  with  acetic  acid,  acetate  of  protoxide  of  copper,  so  as  to  leave 
an  excess  of  carminic  acid  in  the  liquid.  When  dried  it  is  a  brown-colored  hard  mass. 
— Liebiq  and  Kopp's  Report. 

CARNELIAN,  or  CORNELIAN.  ( CorwaZine,  Fr.;  Korneol,  Germ.  \  Cm-nalina,lia\.) 
A  reddish  variety  of  chalcedony,  generally  of  a  clear  bright  tint;  it  is  sometimes  of  a 
yellow  or  brown  color,  and  it  passes  into  common  chalcedony  through  grayish  red. 
Ilerntz,  by  his  analyses,  shows  that  the  color  is  due  to  oxide  of  iron.     He  found 

Per  Cent. 

Peroxide  of  iron 0-()50 

Alumina 0-081 

Iilagnesia 0-028 

Potash 0-0043 

Soda 0-075 

the  remainder  being  Silica. — Dana. 

Carnelians  are  the  stones  usually  employed  when  engraved  for  seals.  The  French 
give  to  those  carnelians  which  have  the  utmost  transparency  and  purity,  the  name  of 
Cumnlitic  d'ancicnne  rocfie.     See  Agate. 

The  late  James  Forbes,  Esq.,  long  a  resident  in  India,  and  with  ample  means  of  refer- 
ence to  the  province  of  Guzerat,  thus  desci-ibes  the  locality  of  the  carnelian  mines: — 

"  Carnelians,  agates,  and  the  beautifully  variegated  stones  improperly  called  Mocha 
Stones,  form  a  valuable  part  of  the  trade  at  Cainbay.  The  best  agates  and  carnelians 
a>re  found  in  peculiar  strata,  thirty  feet  under  the  surface  of  the  earth,  in  a  small  tract 


310  CARRAGEEN". 

among  the  Rajepiplee  hills  ou  the  banks  of  the  Nerbudda ;  they  are  not  to  be  met  with 
in  any  other  part  of  Guzerat,  and  are  generally  cut  and  polished  in  Cainbay.  On  being 
taken  from  their  native  bed,  they  are  exposed  to  the  heat  of  the  sun  for  two  years:  the 
longer  they  remain  in  that  situation,  the  brighter  and  deeper  will  be  the  color  of  the 
stone.  Fire  is  sometimes  substituted  for  the  solar  ray,  but  with  less  effect,  as  the  stones 
frequently  crack,  and  seldom  acquire  a  brilliant  lustre.  After  having  undergone  this  pro- 
cess, they  are  boiled  for  two  days,  and  sent  to  the  manufacturers  at  Cambay.  The  agates 
are  of  different  hues ;  those  generally  called  carnelians  are  dark,  white,  and  red,  in  shades 
from  the  palest  yellow  to  the  deepest  scarlet. 

"The  variegated  stones  with  landscapes,  trees,  and  water  beautifully  delineated,  are 
found  at  Copper-wange,  or,  more  properly,  Cubbeer-punge,  'The  Five  Tombs,'  a  place 
sixty  miles  distant." — Oriental  Memoirs,  vol.  i.  p.  323,  2d  ed. 

At  Neemoudrn,  a  village  of  the  Rajepiplee  district,  and  three  miles  cast,  are  some 
celebrated  carnelian  mines.  The  country  in  the  immediate  vicinity  of  the  mines  is  but 
little  cultivated  ;  and  on  account  of  the  jungles,  and  their  inhabitants  the  tigers,  no  human 
inhabitants  are  found  nearer  than  Rattumpoor,  which  is  seven  miles  off.  The  miners 
have  huts  at  this  place  when  stones  are  burned. 

The  carnelian  mines  arc  situated  in  the  wildest  parts  of  the  jungle,  and  consist  of 
numerous  shafts  worked  down  perpendicularly  about  4  feet  wide,  the  deepest  about  50 
feet.  Some  extend  at  the  bottom  in  a  horizontal  direction,  but  usually  not  far,  the  nature 
of  these  pits  being  such  as  to  prevent  their  being  worked  a  second  year,  on  account  of 
the  heavy  rains  causing  the  sides  to  fall  in  ;  so  that  new  ones  nmst  be  opened  at  the  con- 
clusion of  every  rainy  season.  The  soil  is  gravelly,  and  consists  chiefly  of  quartz  sand, 
reddened  with  iron  and  a  little  clay.  The  nodules  weigh  from  a  few  ounces  to  even  two 
or  three  pounds,  and  lie  close  to  each  other,  but  for  the  most  part  distinct,  not  being-  in 
strata,  but  scattered  through  the  masses  in  great  abundance. 

On  the  spot,  the  carnelians  are  mostly  of  a  blackish-olive  color,  like  common  dark 
flints,  others  somewhat  lighter,  others  still  lighter  with  a  milky  tinge;  but  it  is  quite  un- 
certain what  appearance  they  will  assume  after  they  have  undergone  the  process  of  burn- 
ing. 

From  Xeenioudra  they  are  carried  by  the  merchants  to  Cambay,  where  they  are  cut, 
polished,  and  formed  into  beautiful  orniimcnts,  for  which  that  city  is  so  justly  celebrated. 
— Cojwland,  Boinbni/  Researches ;  Hamilton's  Description  of  Ilindostan,  4to.  1820. 

Tlie  stones  from  Cambay,  are  offered  in  commerce,  cut  and  uncut,  as  roundish  pebbles 
from  1  to  3  inches  in  diameter.  The  color  of  red  carnelian  of  Cambay  varies  from  the 
palest  fle?h-color  to  the  deepest  blood-red ;  the  latter  being  most  in  demand  for  seals  and 
trinkets.  The  white  are  scarce,  but  when  large  and  uniform  they  are  valuable  ;  the  yellow 
and  variegated  are  of  little  estimation  in  the  Bombay  market. 

The  following  is  a  statement  of  the  Carnklians  exported  by  sea  from  the  port  of  Bom- 
bay to  foreign  and  Indian  stations  not  subject  to  the  Presidency  of  Bombay,  from  1st 
May,  1856,  to  30th  April,  1857  :— 

African  Coast 20,583 

Ar.abian  Gulf 26,157 

Cevlon 2,192 

China,  Hong  Kong 946 

"      Penang,  Singapore,  and  Straits  of  Malacca           -  3,635 

Persian  Gulf 7,777 

Suez 4,755 

East  Indian  ports  of  Malabar 400 

Total  value  in  rupees,  69,046  ;  the  rupee  being  valued  at  two  shillings. 

CARR.\.GEEN.     {Chondrns  crispus.)     Irish  Moss.     See  Alg.«. 

CARRAGEENIN.  The  mucilaginous  constituent  of  carrageen  moss.  It  is  called  by 
some  writers  rer/etable  jellj/  or  rer/i'tabfe  mucilage,  by  others  pectin.  "It  appears  to  me 
(Pereira)  to  be  a  particular  modification  of  mucilage,  and  I  shall  therefore  call  it  carra- 
geenin.  It  Ls  soluble  in  boiling  water,  and  its  solution  forms  a  precipitate  with  diacetate  of 
lead,  and  silicate  of  potash,  and,  if  sufficiently  concentrated,  gelatinizes,  on  cooling.  Car- 
rageenin  is  distinguished  from  ordinary  gum  by  its  aqueous  solution  not  producing  a  pre- 
cipitate on  the  addition  of  alcohol,  Crom  starch  by  its  not  assuming  a  blue  color  with  tinc- 
ture of  iodine;  from  animal  jelly,  l)y  tincture  of  nutgalls  causing  no  precipitate;  from 
pectin,  by  acetate  of  lead  not  throwing  down  any  thing,  as  well  as  by  no  mucic  acid  being 
formed  by  the  action  of  nitric  acid."  Tlie  composition  of  carragcenin  dried  at  212"  F., 
according  to  Schmidt,  is  represented  by  the  formula  C^II'^O'",  so  that  it  appears  to  be  iden- 
tical with  starch  and  sugar.     Mulder,  however,  represents  it  by  the  formula  C-'H"'0'°. 

CARTHAMUS,  or  SAFFLOWER.  The  coloring  matter  of  safflower  has  been  exam- 
ined by  Salvetat;  who  has  found  nnich  difference  in  carthamus  of  reputed  good  quality  ;  a 
few  of  his  results  will  suffice  :  — 


CAKVING  BY  MACHINERY. 


311 


1. 

2. 

3. 

4. 

Water 

G-0 

11-5 

4-5 

4-8 

Albumen    ------- 

3-8 

4-0 

8-0 

1-7 

'    Yellow  colorinff  matter  a   - 

27-0 

30-0 

30-0 

26-1 

i        "             "             "       6   ...        - 

3-0 

4-0 

6-0 

2-1 

Extractive  matter      ----- 

5-0 

4-0 

6-0 

4-1 

Waxy  matter     - 

1-0 

0-8 

1-2 

1-5 

Carthamine        --.-.- 

0-5 

0-4 

0-4 

0-6 

Woody  fibre      - 

50--1: 

41-77 

38-4 

56-0 

Silica 

2-0 

1-5 

3-5 

1-0 

Sesquioxide  of  Iron  and  Alumina 

0-6 

0-1 

1-6 

0-5 

"         "         Manganese          ... 

0-1 

0-1 

0-3 

Sulvetat  has  found  it  advantageous  to  mix  the  red  of  safflower  with  the  pigments  used 
in  porcelain  painting  for  purple,  carmine,  and  violet,  colors  which,  in  consequence  of  the 
difference  of  their  shade  before  and  after  firing,  are  very  liable  to  mislead.  To  avoid  this, 
he  imparts  to  the  pigment,  (consisting  of  flux,  gold,  purple,  and  chloride  of  silver,)  by  means 
of  the  red  of  carthamus  suspended  in  water,  the  same  shade  which  he  desires  to  obtain 
after  firing. 

CARVING  BY  MACHINERY  is  an  art  of  comparatively  modern  date,  nearly,  if  not 
the  whole  of  the  originators  and  improvers  of  it,  being  men  of  tlie  present  day.  It  is  true 
that  the  Medallion  Lathe  and  many  other  appliances  for  ornamental  turning  and  drilling  can 
claim  a  much  earlier  origin,  but  these  can  scarcely  be  called  carving  machines,  and  are  alto- 
gether incapable  of  aiding  the  economy  of  producing  architectural  decorations  of  any  kind. 
We  are  not  aware  of  any  practical  scheme  for  accomplishing  this  oVjject  prior  to  the  patent 
of  Mr.  Joseph  Gibbs,  in  1829,  which  we  believe  was  used  by  Mr.  Nash  in  ornamenting  some 
of  the  floors  of  Buckingham  Palace,  and  on  many  other  works  of  inlaying  and  tracery. 
The  cutting  of  ornamental  forms  in  low  relief  seems  to  have  been  the  principal  object  of 
the  inventor;  and  this  he  accomplished  satisfactorily  by  a  scries  of  ingenious  mechanical 
arrangements,  which  greatly  reduced  the  cost,  while  securing  unusual  accuracy  in  this  kind 
of  work.  Some  modifications  of  machinery  for  copying  busts,  bosses,  and  other  works  in 
bold  relief  are  also  described  in  Mr.  Gibbs's  patents,  but  these  were  never  carried  into  suc- 
cessful practice.      The  tracery  and  inlaying  machine  is  illustrated  hy  jig.  153,  which  is  a 


plan  of  the  machine,      a  is  a  shaft  capable  of  vertical  motion  in  its  bearings,  which  are  in 
the  fixed  framing  of  the  machine  ;    it,  c,  and  d,  e,  are  swing  frames  jointed  together  by  a 


312  CARVING  BY  MACHINERY. 

short  vertical  shaft  a,  and  securely  keyed  to  the  shaft  a.  The  point  b  is  the  axis  of  a 
revolving  tool,  which  is  driven  by  the  belts  <•,  J,  «,  and  the  compound  pulleys/,  g,  h,  which 
increase  the  speed  at  each  step  ;  f,  g,  h,  is  the  table  on  wliieh  the  work  is  fixed  ;  i,  k,  the 
work ;  and  ^•,  I,  a  templet  of  brass  pierced  with  the  horizontal  form  of  the  pattern  to  be 
produced  in  the  wood  ;  this  templet  is  securely  fixed  on  the  top  of  the  work,  or  over  it,  and 
the  machine  is  adjusted  for  action. 

There  is  a  treadle,  not  sliown  in  the  figure,  which  enables  the  workman  to  lift  or  de- 
press the  shaft  a,  and  the  swing  frames  and  tool  attached  to  it ;  he  can  thus  command  the 
vertical  position  of  the  tool  with  his  foot,  and  its  horizontal  position  with  his  hand  by  the 
handles  in,  ?(,  which  turn  freely  on  a  collar  of  the  swing  frame  surrounding  the  mandril  or 
tool-holder.  The  tool,  having  been  brought  over  one  of  the  apertures  of  the  templet  when 
in  rapid  action,  is  allowed  to  sink  to  a  proper  depth  in  the  wood  underneath,  and  the  smooth 
pan  of  its  shaft  is  then  kept  in  contact  with  the  guiding  edges  of  the  templet  and  passed 
round  and  over  the  entire  surface  of  the  figure,  until  a  recess  of  the  exact  size  and  form 
of  tliat  opening  in  the  templet  is  produced  ;  this  process  is  repeated  for  every  other  open- 
ing, and  thus  a  series  of  recesses  ai'c  formed  in  the  oak  flooring  planks  which  correspond 
with  the  design  of  the  templets  used.  To  complete  the  work,  it  is  requisite  to  cut  out  of 
some  darker  or  differently  colored  material  a  number  of  thin  pieces  which  will  fit  these 
recesses,  and  these  arc  produced  in  the  same  way  from  templets  which  will  fit  the  various 
apertures  of  that  first  used  ;  these  pieces  are  next  glued  into  the  recesses,  and  the  surface 
when  planed  and  polished  exhibits  the  pattern  in  the  various  colors  used.  For  inlaying  it 
is  important  that  the  cutting  edge  of  the  tool  should  travel  in  the  same  radius  as  the  cylin- 
drical shaft,  which  is  kept  against  the  edge  of  the  templet ;  but  if  the  tool  is  a  moulded 
one,  a  counterpart  of  its  mouldings  will  be  produced  in  the  work,  while  the  pattern,  in 
planes  parallel  to  that  of  the  panel,  will  have  the  form  of  the  apertures  in  the  templet  used. 
In  this  way,  by  great  care  in  the  preparation  of  the  templets  and  the  tools,  much  of  the 
gothic  tracery  used  in  church  architecture  may  be  produced,  but  the  process  is  more  appli- 
cal)le  to  Bath  stone  than  to  wood  when  moulded  tools  are  requisite. 

Mr.  Irving's  patents  for  cutting  ornamental  forms  in  wood  and  stone  are  identical  in 
principles  of  action  and  in  all  important  points  of  construction  with  the  arrangen.ents  pre- 
viously described.  In  that  of  1843  he  particularly  claims  all  combinations  for  accomphsh- 
ing  the  purpose,  "  provided  the  swing  frame  which  carries  the  cutter,  and  also  the  table  on 
which  the  article  to  be  wrought  is  placed,  have  both  the  means  of  circular  motion."  The 
pierced  templet  is  the  guiding  power,  and  the  work  and  templet  are  fixed  on  a  circular  iron 
table,  which  is  at  liberty  to  revolve  on  its  axis.  The  swing  frame  which  carries  the  cutter 
is  single,  as  in  Mr.  Gibbs's  curved  moulding  machine,  and  its  radius  so  adjusted,  that  an  arc 
drawn  by.  the  tool  would  pass  over  the  centre  of  the  circular  table.  The  mode  of  operating 
with  this  machine  was  to  keep  the  shaft  of  the  tool  against  the  guiding  edge  of  the  templet, 
by  the  joint  movements  of  the  table  on  its  centre,  and  of  the  swing  Irame  about  its  shaft ; 
and  it  will  be  obvious  that  by  this  means  any  point  of  the  table  could  be  reached  by  the 
tool,  and  therefore  any  pattern  of  moulded  work  within  its  range  produced,  in  the  way 
already  described  in  speaking  of  Mr.  Gibbs's  machinery.  But  as  these  modifications  of  the 
original  idea  are  not,  strictly  speaking,  carving  machines,  seeing  that  they  only  produced 
curved  mouldings,  we  need  not  further  describe  them. 

Perhaps  the  most  perfect  carving  machine  which  has  been  made  for  strictly  artistic 
works  is  that  used  by  Mr.  Cheverton  for  obtaining  his  admiraWe  miniature  reductions  of 
life-sized  statuary;  but  we  can  only  judge  of  the  perfection  of  this  machine  by  its  work, 
seeing  that  the  inventor  has  more  faith  in  secrecy  than  patents,  and  has  not  made  it  public. 

The  carving  machinery  which  is  best  known,  and  has  been  most  extensively  used,  is 
that  invented  by  Mr.  Jordan  and  patented  in  184.5,  since  which  date  it  has  been  in  constant 
operation  in  producing  the  carved  decorations  of  the  interior  of  the  Houses  of  Parliament. 

Its  princi])le  of  action  and  its  construction  is  widely  different  from  that  above  described, 
and  it  is  capable  of  copying  any  carved  design  which  can  be  produced,  so  far  as  that  is  pos- 
sible by  revolvinrf  tools  ;  the  smoothness  of  surface  and  sharpness  of  finish  are  neither  pos- 
sible nor  desirable,  because  a  keen  edge  guided  by  a  practised  hand  will  not  only  produce  a 
better  finish,  but  it  will  accomplish  this  part  of  the  work  at  less. cost;  the  only  olyect  of 
using  machinery  is  to  lessen  the  cost  of  production,  or  to  save  time  ;  and  in  appproacliing 
towards  the  finish  of  a  piece  of  carving,  there  is  a  time  when  further  progress  of  the  work 
on  the  machine  would  be  more  expensive  than  to  finish  it  by  hand.  This  arises  from  the 
necessity  of  using  smaller  tools  towards  the  finish  of  the  work  to  penetrate  into  its  sharp 
recesses",  and  the  necessarily  slow  rate  at  which  these  cut  away  the  material ;  it  is  conse- 
quently a  matter  of  commercial  calculation,  how  far  it  is  desirable  to  finish  on  the  machine, 
and  when  to  deliver  it  into  the  hands  of  th-e  artist,  so  as  to  secure  the  greatest  economy. 
This  depends  in  a  great  measure  on  the  hardness  of  the  material ;  rosewood,  ebony,  box, 
ivory,  and  statuary  marble  should  be  wrought  very  nearly  to  a  finish  ;  but  lime,  deal,  and 
Other  soft  woods  sliould  only  be  roughly  pointed. 

Fig.  154  is  a  plan  of  the  machine,  fg.  155  a  front  elevation,  and  fig.  150  a  side  eleva- 


CARVING  BY  MACHINERY. 


313 


tion.  The  same  letters  indicate  the  same  part  in  all  the  figures.  The  carving  machine  con- 
sists of  two  distinct  parts,  each  having  its  own  peculiar  motions  quite  independent  of  tlie 
otlier,  but  each  capable  of  acting  simultaneously  and  in  unison  with  the  other.  The  first, 
or  horizontal  part,  is  the  bed  plate  "  fioating-table,"  &c.,  on  which  the  pattern  and  work  are 
fixed  ;  all  the  motions  of  this  part  are  horizontal.  The  second,  or  vertical  part,  is  that 
wiiich  carries  the  cutters  and  tracer,  the  only  motion  of  which,  except  the  revolution  of  the 
tools,  is  vertical. 

154 


The  horizontal  part  consists  of  three  castings  :  The  bed  plate  a,  n,  c,  n,  which  is  a  rail- 
way supported  on  piers  from  the  floor  and  fixed  strictly  level.  The  carrying  frame  i,  J,  ic, 
L,  mounted  on  wheels  and  travelling  on  the  bed  plate,  (the  long  sides  of  this  frame  are 
planed  into  (v)  rails,)  and  the  "  floating-table  "  m,  n,  o,  p,  which  is  also  mounted  on  wheels 
to  travel  on  the  rails  of  the  carrying  frame.  It  is  called  the  "  floating-table,"  because  it  can 
be  moved  in  any  horizontal  direction  with  almost  as  much  facility  as  if  it  were  a  floating 
body.  Primarily  this  tal)le  has  two  straight-lined  motions  at  right  angles  to  each  other,  but 
by  combination  of  these  it  may  move  over  any  figure  in  an  horizontal  plane  ;  and  because 
this  is  accomplished  without  angular  motion  about  a  centre,  every  point  in  the  surface  of 
the  table  moves  through  the  same  figure  at  the  same  time  ;  hence  the  power  of  producing 
many  copies  of  a  pattern  simultaneously. 

The  second,  or  vertical  part  of  the  machine,  is  a  cast-iron  bridge  supported  on  columns 
across  the  centre  of  the  bed  plate  ;  on  the  centre  of  this  bridge  piece  is  a  wide  vertical 
slide,  5,  0,  with  a  (t)  slotted  bar  on  its  lower  edge  ;  to  this  bar  the  mandril  heads  or  tool- 
holders,  9,  10,  11,  are  bolted,  at  such  distances  apart  as  suits  the  width  of  the  work  in  hand, 
and  in  such  numbers  as  it  is  convenient  to  work  at  one  time.  If  the  framing  of  the  ma- 
chine is  massive  and  well  fixed,  six  or  eight  narrow  pieces  may  be  carved  at  once  ;  but  if 
the  width  of  the  work  is  ecjual  to  half  that  of  the  taljle,  only  one  can  be  done,  as  in  that 
case  half  the  table  is  required  for  the  pattern.  The  motion  of  the  vertical  slide  is  governed 
by  the  workman's  foot  on  the  treadle  r,  q,  s  ;    at  s  balance  weights  are  placed,  so  as  to 


814 


OAEYIN'G  BY  MACHINERY. 
155 


Qq;:::::::::" 


156 


-% 


^. 


wr^ 


CASE-HARDENING. 


315 


adjust  the  force  with  which  the  toola  will  descend  on  the  work  ;    any  pressure  on  the  foot- 
board R  lifts  the  slide,  and  with  it  the  tools  and  tracing  point. 

Returning  to  the  horizontal  part  of  the  machine,  (/,  e,  f,  g,  is  the  pattern  or  original 
carving  whicli  is  to  he  copied,  and  /(,  i,j,  k,  two  copies  in  progress.  The  movements  of  the 
floating-table  are  managed  by  the  workman  with  the  hand-wheels  u,  v  ;  the  left  hand,  on  u, 
directs  the  lateral  motion  on  the  frame,  and  the  right,  on  v,  directs  the  longitudinal  motion 
on  the  bed  plate ;  the  left-hand  movement  is  communicated  by  the  cord  x,  x,  which  is  fixed 
to  brackets  w,  w,  underneath  the  table,  and  makes  one  turn  round  a  small  pulley  on  the 
axis  of  the  wheel  u.  The  right-hand  movement  is  commurficated  by  the  cord  z,  which  is 
fastened  to  each  end  of  the  bed  plate,  and  makes  one  or  two  turns  round  the  pulley  k. 
Wiien  at  work  the  man  stands  inside  the  frame  of  the  bed  plate,  with  his  right  foot  on  the 
board  r  and  his  hands  on  the  steering  wheels ;  on  releasing  the  pressure  of  the  foot,  the 
vertical  slide  descends  by  its  unbalanced  weight  until  the  tracer  h  comes  in  contact  with  the 
pattern  ;  the  cutters  m,  in,  are  made  to  revolve  by  steam  power  at  the  rate  of  seven  thou- 
sand times  per -minute,  and  are  so  shaped  as  to  cut  like  a  revolving  gouge,  so  that  they 
instantly  cut  away  all  the  superfluous  material  they  come  in  contact  with  ;  and,  by  the  time 
the  tracer  has  been  brought  over  every  part  of  the  pattern,  the  pieces  fi,  i,  J,  k  will  have 
become  exact  copies  of  it. 

So  far  as  panel  carving  is  concerned,  the  whole  machine  has  been  described  ;  but  it  is 
requisite  to  elaborate  its  construction  a  little  more  for  the  purpose  of  carving  on  the  round,  and 
copying  subjects  which  require  the  blocks  to  be  cut  into  in  ail  possible  directions.  Various 
modifications  have  been  used,  but  we  shall  only  explain  that  which  we  think  best  adapted  to 
ornamental  carving.  It  is  not  requisite  that  wo  should  go  into  the  various  applications  of 
this  machine,  to  the  manufiicture  of  printing  blocks,  ship's  blocks,  gunstocks,  letter  cutting, 
tool  handling,  cabinet  shaping,  &c.,  &c.,  all  of  wliicli  have  been  shown  from  time  to  time  to 
be  within  its  power ;  nor  is  it  requisite  to  describe  more  recent  inventions  founded  on  it,  as 
they  will  more  properly  come  under  other  heads. 

When  the  machine  is  intended  to  copy  any  form  which  can  be  carved  by  hand,  the 
floating-table  is  differently  constructed,  but  all  other  parts  remain  as  before.  In  the  float- 
ing-table used  for  this  purpose,  there  is  an  opening  in  the  centre  of  the  table,  and  a  turning 
plate,  which  is  mounted  a  few  inches  above  the  level  of  the  table,  to  turn  in  bearings  in 
standards.  Underneath  the  turning  plate,  and  forming  a  part  of  it,  there  is  an  arc  of  rather 
more  than  half  a  circle,  having  its  centre  in  the  axis  on  which  the  plate  turns,  and  this  arc 
is  cogged  on  its  edge  to  fit  the  threads  of  the  tangent  screw  on  the  axis  of  the  wheel,  so 
that  by  turning  this  wheel,  and  dropping  its  detent  into  any  cog,  the  workman  can  fix  the 
plate  at  any  angle  with  the  horizon.  There  are  three  chucks  fitted  into  sockets  of  the  turn 
plate,  and  these  are  similarly  divided  on  their  edges  by  holes  or  cogs,  into  which  detents 
fall,  so  as  to  secure  them  steadily  in  any  required  position. 

When  in  use  one  chuck  carries  the  pattern,  and  two  other  chucks  the  work.  The  pro- 
cess of  carving  is  precisely  the  same  as  before ;  but  in  consequence  of  the  work  and  pat- 
tern being  so  mounted  that  it  can  be  turned  into  every  possible  position  with  respect  to  tho 
cutters,  any  amount  of  undercutting  which  is  possible  in  hand  carving  is  also  possible  in 
machine  carving. 

In  going  through  the  process  the  workman  will,  of  course,  attack  the  work  when  it  isi 
placed  in  a  favorable  position  for  the  tools  to  reach  a  large  portion  of  its  surface ;  and  hav- 
ing completed  as  much  as  possible  on  that  face,  he  will  turn  all  the  chucks  through  the  same 
number  of  divisions  ;  the  pattern  and  work  will  still  have  the  same  relative  position  to  each 
other  as  before,  but  an  entirely  new  face  of  both  will  be  presented  to  the  tools;  this  will  be 
carved  in  like  manner,  and  then  another  similar  change  made,  and  so  on  until  all  has  been 
completed  which  can  be  reached  without  changing  the  angular  position  of  the  turning  plate. 
This  can  be  done  by  the  wheel,  and  when  a  sufficient  number  of  these  changes  have  been 
gone  through,  the  work  will  be  complete  on  every  face,  although  the  block  may  have  re- 
quired to  be  pierced  through  in  fifty  different  directions. — T.  B.  J. 

CASE-HARDENIXG.  When  case-hardening  is  required  to  terminate  at  any  particular 
part,  as  a  shoulder,  the  object  is  left  with  a  band  or  projection  ;  the  work  is  allowed  to  cool 
without  being  immersed  in  water ;  the  band  is  turned  off,  and  the  work,  when  hardened  in 
t!io  open  fire,  is  only  effected  as  far  as  the  original  cemented  surface  remains.  This  inge- 
nious method  was  introduced  by  Mr.  Roberts,  of  Manchester,  who  considers  the  success  of 
the  case-hardening  process  to  depend  on  the  gentle  application  of  the  heat ;  and  that,  by 
proper  management  not  to  overheat  the  work,  it  may  be  made  to  penetrate  three-eighths  of 
an  inch  in  four  or  five  hours. — ILdtzaplfcl. 

The  recent  application  of  prussiate  (ferrocyanatc)  of  potash  to  this  purpose  is  a  very 
interesting  chemical  proljlem.  The  piece  of  iron,  after  being  polished,  is  to  be  made 
brightly  red-hot,  and  then  rubbed  or  sprinkled  over  witli  the  above  salt  in  fine  powder,  upon 
the  part  intended  to  be  hardened.  The  prussiate  l)eing  decomposed,  and  apparently  dissi- 
pated, the  iron  is  to  bo  quenched  in  cold  water.  If  the  process  liivs  been  well  managed,  the 
surface  of  the  metal  will  have  become  so  hard  as  to  resist  the  file.    Others  propose  to  smear 


316 


CASK. 


over  the  surface  of  the  iron  with  loam  made  into  a  thin  paste  with  a  strong  solution  of  the 

prussiate,  to  dry  it  slowlj-,  then  expose  the  whole  to  a  nearly  white  heat,  and  finally  plunge 

the  iron  into  cold  water,  when  the  heat  has  flillen  to  dull  redness.     See  Stekl.  "^ 

CASK.     {7'o7inean,  Fr.  ;  Fa.ss,  Germ.)      Much  ingenuity  has  been  displayed  in  cuttin"' 

the  curvilinear  and  bevelled  edges  of  the  staves  of  casks  by  circular 

saws.     Sir  John  Robinson  proposed  many  years  back  that  the  stave 

should  be  bent  to  its  true  curve  against  a  curved  bed,  and  that  while 

thus  restrained  its  edges  should  be  cut  by  two  saws  s  s,  placed  in 

radii  to  \lie  circle,  the  true  direction  of  the  joint  as  shown  by  the 

dotted  circle  Jirj.  157,  representing  the  head  of  the  cask. 

Mr.  Smart  cuts  the  edges  of  thin  staves  for  small  casks  on  the 
ordinary  saw-bench,  by  fixing  the  thin  wood  by  two  staples  or  hooks 
to  a  curved  block,  the  lower  face  of  which  is  bevelled  to  give  the 
proper  chamfer  to  the  edges,  fg.  158.  One  edge  having  been  cut,  the 
stave  is  released,  changed  end  for  end,  and  refixed  against  two  pins  which  determine  the 
position  for  cutting  the  second  edge,  and  make  the  staves  of  one  common  width.  The 
curved  and  bevelled  block  is  guided  by  two  pins  pp,  which  enter  a  straight  groove  in  the 
bench  parallel  with  the  saws.  This  mode  of  bending  is  from  various  reasons  ibund  inappli- 
cable to  large  staves,  and  these  are  cut,  as  shown  in  three  views,  fg.  159,  whilst  attached 


158 


159 


to  a  straight  bed,  the  bottom  of  which  is  also  bevelled  to  tilt  the  stave  for  chamfering  the 
edge.  To  give  the  curve  suitable  to  the  edge,  the  two  pins  on  the  under  side  of  the  block 
run  in  two  curved  grooves  g  rj  in  the  saw-bench,  which  cause  the  staves  to  sweep  past  the 
saw  in  the  arc  of  a  very  large  circle,  instead  of  in  a  right  line,  so  that  the  ends  are  cut 
narrower  than  the  middle.  Mr.  Smart  observes  {Trans.  Soc.  of  Arts,  vol.  xlvii.)  that  in 
staves  cut  whilst  straight,  the  edges  become  chamfered  at  the  sime  angle  throughout,  which 
although  theoretically  wrong  is  sufficiently  near  for  practice  ;  the  error  is  avoided  when  the 
staves  are  cut  whilst  bent  to  their  true  curvature. 

The  necessary  flexibility  which  is  required  for  bending  the  staves  of  casks  is  obtained 
by  steaming  them  in  suitable  vessels  in  contact  with  rigid  moulds.  By  Taylor's  patent  ma- 
chinery for  making  casks,  the  blocks  intended  for  the  staves  are  cut,  out  of  white  Canada 
oak,  to  the  size  of  thirty  inches  by  five,  and  smaller.  They  arc  well  steamed,  and  then 
sliced  into  pieces  one-half  or  five-eighths  of  an  inch  thick,  at  the  rate  of  200  a  minute,  by 
a  process  far  more  rapid  and  economical  than  sawing,  the  instrument  being  a  revolving  iron 
plate,  of  12  or  14  feet  diameter,  with  two  radical  knives  arranged  somewhat  like  the  irons 
of  an  ordinary  plane  or  spokeshave. 

CASSAREEP  or  CASSIREEPE.  The  concentrated  juice  of  the  roots  of  the  bitter 
cassava  flavored  l>y  aroniatics.  It  is  used  to  flavor  soups,  and  other  dishes,  and  is  the  basis 
of  the  West  Indian  dish  prpper-pot.  In  French  Guiana,  the  term  cabion  is  applied  to  a 
similar  condiment. — Percira. 

CASSITERITE.  Oxide  of  Tin  ;  Stream  Tin.  Stream  Tin  is  the  alluvial  dlbris  of  tin 
veins.  (See  Tin  Ore.)  This  is  one  of  the  very  olyectionablc  names,  of  which  a  very 
great  number  have,  of  late  years,  been  introduced  into  the  science  of  Mineralogy. 

CASSIUS,  purple  powder  of.  Professor  Graham,  in  his  "  Elements  of  Chemistry," 
gives  the  following  account  of  the  purple  of  cassius,  and  of  its  preparation  :  "  AVhcn 
protochloridc  of  tin  is  added  to  a  dilute  solution  of  gold,  a  purple  powder  falls.  It  is 
obtained  of  a  finer  tint  when  protochloridc  of  tin  is  added  to  a  solution  of  the  sesqnichlo- 
ride  of  iron  till  the  color  of  the  liquid  takes  a  shade  of  green,  and  the  liquid  in  that  state 
added,  drop  by  drop,  to  a  solution  of  sesquichloride  of  gold  free  from  nitric  acid,  and  very 
dilute.  After  24  hours  a  brown  powder  is  deposited,  which  is  slightly  transparent,  and 
purple-red,  by  transmitted  light:  when  dried  and  rubbed  to  powder,  it  is  of  a  dull  bhie 
color.  Heated  to  redness  it  loses  a  little  water  but  no  oxygen,  and  retains  its  former 
appearance.     If  washed  with  anmioiiia,  on  the  filter,  while  still  moist,  it  dissolves,  and  a 

purple  liquid  passes,  which  rivals  the  hypermanganate  of  potash  in  beauty It  may 

al.so  be  formed  by  fusing  together  2  parts  of  gold,  3i  parts  of  tin,  and  15  parts  of  silver, 
under  borax,  to  prevent  the  oxidation  of  the  tin,  and  treating  the  alloy  with  nitric  acid, 
to  dissolve  out  the  silver;  a  purple  residue  is  left,  containing  the  tin  and  gold  that  were 
employed." 


CEDAR. 


317 


"  Berzelius  proposed  the  theory  that  the  powder  of  Cassius  may  contain  the  true  prot- 
oxide of  gold  combined  with  sesquioxide  of  tin,  AuOSu^O^,  a  kind  of  combination  contain- 
ing an  association  of  three  atoms  of  metal,  which  is  exemplified  in  black  oxide  of  iron, 

spinele,  Franklinite,  and  other  minerals A  glance  at  its  formula  shows  how  readily 

the  powder  of  Cassius,   as  thus  represented,  may  pass  into  gold  and  binoxide  of  tin, 
AuOSn'0^=Au-|-2SnOo." — Grahaui  and  Walts. 

CASTORINE.  A  substance  existing  in  castoreum.  Its  chemical  formula  is  not  known 
and  its  entire  history  requires  to  be  freshly  investigated.  It  is  obtained  by  treating  the 
secretion  of  the  castors  with  hot  alcohol,  and  filtering  through  a  Platamour's  ebullition 
funnel.  On  cooling,  the  alcohol  deposits  crystals  of  a  fiitty  substance.  The  castorine  is 
retained  in  the  mother  liquor,  and  is  procured  by  evaporation  on  the  water-bath  to  a  small 
bulk,  and  then  setting  aside  to  allow  crystals  to  form.  Castorine  crystallizes  in  needles 
possessing  a  slight  odor  of  castoreum. — 0.  G.  W. 

CASTOR  OIL.  The  expressed  oil  of  the  seeds  of  the  Palma  C/irlsii  or  Ricinus  com- 
munis, a  native  tree  of  the  West  Indies  and  South  America  ;  but  which  has  been  cultivated 
in  France,  Italy,  and  Spain. 

In  England  the  castor  oil  is  expressed  from  the  seeds  by  means  of  powerful  hydraulic 
presses  fixed  in  rooms  artificially  heated.  It  is  purified  by  repose,  decantation,  and  filtra- 
tion, being  bleached  in  pale-colored  Winchester  quart  bottles  which  are  exposed  to  light  on 
the  tops  of  houses.  Unbleached  castor  oil  is  certainly  more  acrid  and  possesses  more  pur- 
gative properties  than  such  as  has  been  long  exposed  to  the  light ;  we  may  therefore  infer 
that  the  acrid  reu)i  of  the  oil  has  undergono  some  chemical  change.  In  America  the  oil  is 
expressed  from  the  seeds  by  pressure  between  heated  plates.  In  the  East  Indies,  women 
shell  the  fruit ;  the  seeds  are  placed  between  rollers  and  crushed  ;  they  are  then  put  into 
hemp  cloths,  and  pressed  in  the  hydraulic  press.  The  oil  thus  procured  is  afterwards  heated 
with  water  in  a  tin  boiler,  until  the  water  boils,  by  which  the  mucilage  or  albumen  is  sepa- 
rated as  a  scum.  The  East  Indian  castor  oil  is  sold  in  England  as  cold  drawn.  The  follow- 
ing is  the  composition  of  castor  oil : — 

Ure.  Saussure. 

Carbon 74-00  74-178 

Hydrogen 10-29  10-034 

Oxygen 15-71  14-718 


100-000         100-000 

CATALYSIS.  A  term  introduced  to  denote  the  very  peculiar  phenomenon  of  one  body 
establishing,  by  its  mere  presence,  a  like  condition  in  another  body  to  that  which  exists  in 
itself.  Thus  a  piece  of  meat  undergoing  the  putrefactive  fermentation,  almost  immediately 
sets  up  a  similar  action  in  fresh  meat,  or  produces  in  a  saccharine  fluid  that  motion  which  is 
known  as  vinous  fermentation.  The  action  of  the  yeast  plant, — a  living  organization, — 
establishes  an  action  throughout  a  large  quantity  of  an  infusion  of  malt, — fermentation,  or 
that  disturbance  which  leads  to  the  conversion  of  sugar  into  alcohol.  This  catalytic  power 
is  ill  understood,  and  we  are  content  to  hide  the  imperfection  of  our  knowledge  under  a 
sounding  name. 

CATECHINE.  Catechuic  Acid.  When  Gambir  catechu  is  treated  with  water,  an 
insoluble  residue  is  left,  which  has  been  termed  by  Nees  resinous  tannin.  Its  composition 
is  C'^H"Ol 

CAT'S  EYE.  A  translucent  quartz,  presenting  peculiar  internal  reflections.  This 
effect  is  said  to  be  owing  to  filaments  of  asbestos.  When  cut  en  cabochon,  it  is  esteemed 
as  an  ornamental  stone. 

CEDAR.  {Cklre,  Fr. ;  Ceder,  Germ.)  The  cedar  of  Lebanon,  or  great  cedar,  {Pimis 
cednis,)  is  a  cone-bearing  tree.  This  tree  has  been  famous  since  the  days  of  Solomon,  who 
used  it  in  the  construction  of  the  temple.  The  wood  has  been  obtained  from  Crete  and 
Africa. 

Specimens  have  also  been  procured  from  Morocco,  showing  the  probability  that  the 
range  of  the  tree  not  only  extends  over  tiio  whole  group  of  mountains  which  is  situate 
Ijctween  Damascus  and  Tripoli  in  Syria,  and  which  includes  tlie  Libanus  and  Mounts  Araa- 
nus  and  Taurus  of  antiquity,  and  various  others, — but  that  its  distribution  on  the  moun- 
tainous regions  of  North  Africa  is  extensive. 

Indeed,  if  we  are  to  suppose  that  the  cedar  and  the  cedar  wood  mentioned  by  many  of 
the  ancient  writers  referred  exclusively  to  tlie  Lcl):iiion  species,  wo  must  l)elicve  that  its 
distribution  at  one  period  extended  over  countries  where  no  trace  of  its  having  existed  now 
remains.  Egypt,  Crete  and  Cyprus  are  mentioned  l)y  I'hny  and  Tlieophrastus  as  native 
habitats  of  the  cedrus ;  we  may  thus  fiiirly  infer  that  the  ccdrus  of  the  ancients  as  fre- 
quently had  reference  to  the  other  coniferye  as  to  the  Lebanon  species. 

The  pencil  cedar  is  the  Junipcrus  Virrfijiiana.  It  is  imported  from  America  in  pieces 
from  6  to  10  inches  square.  Tiie  grain  of  the  wood  is  remarkably  regular  and  soft,  on 
which  account  principally  it  is  used  for  tlie  manufacture  of  pencils,  and  from  its  agreeable 
scent  for  the  inside  of  small  cal)inets  ;  it  is  also  made  into  matches  for  the  drawing  room. 


318  CEDEIKET. 

The  general  use  of  the  cedar  wood  dates  from  the  highest  antiquity.  Pliny  makes  men- 
tion of  cedar  wood  and  the  uses  to  which  it  was  applied,  and  cites,  as  examples  of  its  dura- 
bility and  imperishable  nature,  the  timber  of  a  temple  of  Apollo  at  Utica,  in  Africa,  which, 
wlien  nearly  2,000  years  old,  was  found  to  be  perfectly  sound, — and  the  famous  statue  of 
Diana  in  the  temple  of  Saguntum  in  Spain.  Cedria,  an  oil  or  resin  extracted  from  a  cedar, 
was  also,  according  to  Vitruvius,  used  to  smear  over  the  leaves  of  the  papyrus  to  prevent 
the  attacks  of  worms  ;  and  Pliny  states  that  the  Egyptians  applied  it  with  other  drugs  in 
the  preparation  of  their  mummies  ;  but  whether  this  extract  was  obtained  from  the  Leba- 
non cedar  or  from  trees  belonging  to  the  genus  Cup7-essus  or  Jimijjerzcs,  which  also  afford 
odoriferous  resins,  it  is  now  impossible  to  ascertain. 

In  regard  to  the  cedar  and  cedar  wood  mentioned  in  profane  history,  it  is  difficult,  from 
what  we  have  already  stated,  to  determine  what  has  reference  to  the  true  cedar,  and  what 
belongs  to  other  coniferous  species ;  all  that  we  can  know  for  certainty  is  that  a  wood  called 
cedar,  distinguished  for  its  incorruptible  nature,  was  frequently  used  for  purposes  most 
important  in  the  eyes  of  the  pagan,  viz.,  in  the  building  and  decoration  of  their  temples, 
and  for  the  statues  or  images  of  their  heroes  and  gods. 

The  peculiar  balsamic  odor  of  cedar  has  long  been  held  as  a  means  to  preserve  articles 
from  the  attacks  of  insects  ;  chips  and  shavings  of  the  wood  have  been  in  this  way  kept  in 
collections  of  linen,  papers,  and  objects  of  preservation.  Cabinets  have  been  recommended, 
or  at  least  the  drawers  and  fittings,  to  be  made  of  cedar.  That  the  popular  character  may 
receive  its  due  limitation,  it  may  be  useful  to  call  attention  to  some  facts  when  cedar  is  em- 
ployed as  a  means  of  preservation. 

That  the  odoriferous  substance  when  diffused  may  affect  some  forms  of  organic  life,  is 
not  disputed,  but  it  is  as  probable  some  of  the  effect  may  be  due  to  covering  the  insect 
with  a  coating  of  varnish,  alike  irritating  and  interfering  with  the  texture  of  the  surfaces 
of  the  body  ;  but  the  rule  cannot  be  general ;  if  the  creatures  have  a  sufficient  hardihood 
they  may,  and  indeed  do,  attack  the  wood  itself 

The  following  cases  will  show  that  the  substances  emanating  from  cedar  may  produce 
unexpected  interference.  51r.  Vulliaray  states  that  George  III.  had  a  cabinet  in  the  obser- 
vatory at  Kew  with  drawers  of  cedar  wood  in  them  ;  watches  were  placed  with  the  inten- 
tion of  keeping  them  goin^.  In  a  short  time  they  all  came  to  rest ;  the  experiment,  how- 
ever, repeated,  had  the  same  result :  on  examination,  the  oil  used  in  different  parts  of  the 
watches  was  found  to  be  completely  changed  into  a  substance  like  gum.  Mr.  Farcy's  obser- 
vations, also  communicated  to  the  Institution  of  Civil  Engineers,  still  more  show  the 
extraordinary  atmosphere  produced  in  close  caliinets  of  cedar  wood,  and  of  the  effects 
upon  delicate  objects.  The  late  Mr.  Smith,  of  Derby,  having  shown  him  a  small  collection 
of  minerals  which  had  been  locked  up  in  closely  fitted  drawers  of  cedar  wood  ;  on  opening 
the  drawers  for  the  first  time  after  some  months,  the  minerals  were  found  to  be  covered 
with  a  gummy  matter  having  the  strong  odor  of  cedar,  and  troublesome  to  rcm.ove  ;  the 
bright  surface  of  the  crystals  appeared  as  if  varnished  in  an  unskilful  manner.  The  cedar 
had  given  off  a  vapor  that  had  condensed  on  all  the  minerals,  and  the  same  effect  might  be 
expected  to  be  produced  upon  watches,  metals,  and  other  substances. 

Indeed,  cases  are  known  where  the  action  of  cedar  has  produced  unpleasant  effects,  and 
not  without  exciting  the  idea  of  remote  danger.  A  bundle  or  package  of  black  lead  pen- 
cils, the  wood  as  usual  of  cedar,  had  been  kept  in  stock  upon  a  shelf,  wrapped  in  paper :  by 
the  heat  of  the  gas,  &c.,  the  cedar  vapor  had  attacked  tlie  paper  and  its  materials;  the 
paper  seemed  thick  and  stiffened  as  with  varnish,  forming  one  mass  with  the  pencils,  and 
damaging  other  paper  and  articles  of  stock  near,  while  the  paper  was  rendered  highly 
inflammal)]e,  burning  with  a  great  flame.  This  case  was  laid  before  the  officers  of  the  So- 
ciety of  Arts,  who  are  desirous  of  extendir;g  the  proper  uses  of  cedar  wood,  and  of  avoid- 
ing the  evils  arising  from  unsuspected  chemical  action. — T.  J.  P. 

CEDRIRET.  A  singular  compound  of  unknown  composition  existing  in  wood-tar. 
When  crude  creosote  is  dissolved  in  potash  and  acetic  acid  is  added,  creosote  separates.  If 
the  creosote  be  decanted  and  the  solution  of  acetate  of  potash  be  distilled,  a  fluid  is 
oVttained  at  a  certain  epoch  of  the  distillation,  which,  when  dropped  into  persulphate  of 
iron,  forms  a  network  of  crj-stals.  This  is  cedriret.  It  has  not  yet  been  observed  in  coal 
naphtha. 

CELESTIXE.  (S/rontiane  sulfatlc,  Fr.  ;  Co'exfris,  Germ.)  Celestine  is  usually  asso- 
ciated with  secondary  or  Silurian  limestone  or  sandstone,  also  with  trap-rocks ;  and  it  is 
fdund  in  the  red  marl  formations  associated  with  gypsum.  In  Sicily  it  is  commonly  asso- 
ciiited  with  sulphur.  The  celestine  of  Girgenti  was  found  by  Stromeyer  to  be  composed  as 
follows : — 

Sulphuric  acid 48-08 

Strontian      --.......         56'y5 

Red  oxide  of  iron         .......  0*03 

Carbonate  of  lime 0"09 

Water 0'18 


CHARCOAL.  319 

This  mineral  is  found  in  Sicily,  at  Bey  in  Switzerland  and  Corril  in  Spain.  It  exists  at 
Aust  Ferry  near  Bristol,  in  trap-rooks  near  Tantellan  in  the  East  Lothians,  and  at  Calton 
Hill,  Edinburgh.  Dana  gives  several  localities  for  celestine  in  America.  It  is  decomposed 
by  ignition  with  charcoal  into  sulphide  of  strontia,  which  is  converted  into  the  nitrate  by 
the  action  of  nitric  acid. 

CEMENTS.  (^Gimentx,  Fr. ;  Cdmcntc,  Kitte,  Germ.)  Substances  which  are  capable  of 
assuming  the  liquid  form  and  of  being  applied  between  the  surfaces  of  bodies  so  as  to  unite 
them  firmly  when  solidifying.     They  are  of  very  varied  character. 

Gum,  glue,  and  paste  are  cements,  the  uses  of  which  are  well  known. 

Sir  John  Robinson's  cement  he  thus  describes : — 

"  If  it  be  wished  to  dissolve  good  isinglass  in  spirits  of  wine,  it  should  first  be  allowed 
to  soak  for  some  time  in  cold  water,  when  swelled  it  is  to  be  put  into  the  spirit,  and  the 
bottle  containing  it  being  set  in  a  pan  of  cold  water  may  be  brought  to  the  boiling  point, 
when  the  isinglass  will  melt  into  a  uniform  jelly,  without  lumps  or  strings,  which  it  is  apt  to 
have  if  not  swelled  in  cold  water  previously  to  being  put  into  spirits.  A  small  addition  of 
any  essential  oil  diminishes  its  tendency  to  become  mouldy. 

"  If  gelatine,  which  has  been  swelled  in  cold  water,  be  immersed  in  linseed  oil  and 
heated,  it  dissolves,  and  forms  a  glue  of  remarkable  tenacity,  which,  when  once  dry,  per- 
fectly resists  damp,  and  two  pieces  of  wood  joined  by  it  will  separate  anywhere  else  rather 
than  at  the  joint.  Ordinary  glue  may  be  thus  dissolved,  and  sometimes  a  small  quantity 
of  red  lead  in  powder  is  added." 

Lapidaries'  cement  is  made  of  resin,  tempered  with  beeswax  and  a  little  tallow,  and 
hardened  with  red  ochre  or  Spanish  brown  and  whiting. 

Opticians'  cement,  for  fixing  glasses  for  grinding,  is  made  by  sifted  wood  ashes  with 
melted  pitch,  the  essential  oil  of  which  ie  absorbed  by  the  wood  ashes,  and  the  adhesiveness 
of  the  pitch  is  therefore  reduced.  The  proportions  are  somewhat  dependent  on  the  tem- 
perature of  the  weather  and  the  qualities  of  the  pitch  ;  but  generally  about  4  lbs.  of  wood 
ashes  to  14  lbs.  of  pitch  are  employed,  and  the  cement,  if  too  bard  and  brittle,  is  softened 
with  hog's  lard  and  tallow. 

Japanese  cement  is  said  to  be  prepared  by  mixing  rice  flour  intimately  with  cold  water, 
and  then  boiling  the  mixture  :  it  is  white,  and  dries  nearly  transparent.     See  Mortar. 

CEYLON"  MOSS.     {Plocaria  Candida.)     See  Alg^. 

CHALLIS.  About  the  year  1832  this  article  was  introduced,  certainly  the  neatest, 
best,  and  most  elegant  silk  and  worsted  article  ever  manufactured.  It  was  made  on  a  simi- 
lar principle  to  the  Norwich  crape,  only  thinner  and  softer,  composed  of  much  finer  mate- 
rials ;  and  instead  of  a  glossy  surface,  as  in  Norwich  crapes,  the  object  was  to  produce  it 
without  gloss,  and  very  pliable  and  clothy.  The  best  quality  of  challis,  when  finished  with 
designs  and  figures,  (either  produced  in  the  loom  or  printed,)  was  truly  a  splendid  fabric, 
which  commanded  the  attention  of  -the  higher  circles,  and  became  a  favorite  article  of 
apparel  at  their  fashionable  resorts  and  parties.  The  worsted  yarn  for  the  weft  of  this 
article  was  spun  at  Bradford,  from  numbers  52's  to  64's.  The  making  of  the  challis  fabric 
soon  afterwards  commenced  in  the  north. — Jaines'.i  History  of  Woollen  Manufacture. 

CHALCEDONY.  A  hard  mineral  of  the  quartz  family,  often  cut  into  seals.  Under  it 
may  be  grouped  common  chalcedony,  heliotrope,  chrysoprase,  plasma,  agate,  belonging  to 
the  rhombohedral  system,  onvx,  cat's  eye,  sardonyx,  carnelian,  and  sard. 

CHAMOMILE  FLOWERS.  The  Atit/iemi.'s  nobilh  of  Linnaus.  The  chamomile  grows 
very  abundantly  in  Cornwall,  and  some  other  parts  of  England.  It  is  cultivated  at  Mitcham 
and  in  Derbyshire,  for  the  London  market.  The  chamomile  is  used  medicinally,  and  is  em- 
ployed by  some  brewers  to  substitute  hojjs  in  bitter  beer.  It  would  be  well  if  no  more 
objectionable  bitter  were  employed. 

In  185G  we  imported  72,751  lbs. 

CHARCOAL.  The  fixed  residuum  of  vegetables  when  they  are  exposed  to  ignition 
out  of  contact  of  air. 

For  the  purpose  of  showing,  within  a  limited  space,  the  products  of  dry  distillation 
OF  vroon,  the  follo«'ing  list  has  been  compiled  for  this  work  by  the  kindness  of  a  friend 
engaged  in  tliose  manufactures.  For  more  specific  information,  see  Dkstrdctive  Dis- 
tillation, and  the  articles  enumerated  under  their  special  heads. 

The  only  products  of  the  dry  distillation  of  wood  at  present  of  any  commercial  im- 
portance, are  charcoal,  acetic  acid,  naphtha,  and,  in  a  minor  degree,  tar  and  creosote. 

The  products  of  wood  are,  however,  very  numerous,  and,  when  cxaniinod  chemicidly, 
found  to  be  very  complex  in  character  and  constitution,  many  of  them  being  very  little 
understood. 

They  are  gaseous,  liquid,  and  solid. 

Tlic  gaseous  products  are  those  not  condcnsible  by  ordinary  means,  viz. : — 
Carbonic  oxide. 
Carbonic  acid. 

Light  carburcttcd  hydrogen,  or  marsh  gas. 
defiant  gas. 


320 


C)SE£SC 


Ordinary  naphtha,  ov  \ /^,^^^^^  ^j.  ^^^^^y  ,     ^^  ,,^^.^,  .j 
pjrohgaeous spirit.  |  ^,,^o,,,/syn.  with  pyroacetic 


These  are  usually  employed  (such  as  are  combustible)  for  heating  purposes  iu  the 
manufactories  where  found. 

llic  liquid  products  are  water,  containing  from  C7o  to  10%  of  dry  acetic  acid,  am- 
monia, and,  associated  with  them  under  the  ordinary  names  of  tar  and  naphtha,  numerous 
oily,  ethereal,  and  resinous  bodies. 

The  following  hst  will  comprehend  the  greater  number  of  these  bodies  : — 
Water. 

Acetic  acid  in  its  crude  state,  called  pyroligneous  acid. 
Ammonia. 

(  Hydrate  of  mcthjile,  syn.  with  spirit  of  wood  and  methylic  alcohol. 
'  rie  acetic  aether, 
lacetic  spirit. 
r  Benzole,  ■^ 

'.  "j    J   y  .1  1  '^'    (According  to  the  researches  of  Cahours  these  are  all  hydro- 

■    1  tl       i   r        l'     r      carbons,  and  separated  by  him  from  crude  spirit  of  wood. 

\.  Cymole.    J 
From  the  distillation  of  tar  are  obtained,  besides  many  of  the  foregoing,  which  would 
come  under  the  name  of  "  lif/ht  ollx"  from  their  low  specific  gravity : 
Oils  heavier  than  icaler,  besides  residuary  resin  or  pitch — 

Xylite.  Picamar.  Paraffine. 

Mesite.  Cedriretc.  Resiu  or  pitch. 

Capnomore.  Pittacal. 

Solid  Products :  Pyrosanthinc,  Charcoal. — C.  EI.  B.  H. 
CHEESE  [composition  of) : — 


Ash  of  the 
substance. 

Nitrogen. 

Fat. 

TVater. 

Free 

Normal. 

Dry. 

Normal. 

Dry. 

from  ash. 

Normal 

Dry. 

Per  Ct. 

Per  Ct. 

Per  Ct. 

Per  Ct. 

Per  Ct. 

Per  Ct. 

Per  Ct. 

Per  Ct. 

Cheese 

from  Chester 

3ir39 

4-78 

6-88 

5-56 

8-00 

8-59 

25-48 

36-61 

"      Parmesan 

30-31 

7-09 

10-18 

5-48 

7-87 

8-76 

21-68 

31-12 

"      Neufchatel 

61-87 

4-25 

11-17 

2-28 

5-99 

6-07 

18-74 

49-15 

"      Brie 

53-99 

5-63 

12-08 

2-39 

5-14 

5-85 

24-83 

53-29 

"      Holland 

41-41 

6-21 

10-61 

4-10 

7-01 

7-84 

2506 

42-78 

"      Gruyere 

3-2 -05 

4-79   i    7-05 

6-40 

7-96 

8-56 

28-40 

41-Sl 

Pat/en  Journal  Pharma. 
CHEMICAL  FORMUL.(T}.  The  term  formula,  in  ordinary  chemical  language,  is  always 
understood  to  mean  the  collection  of  symbols  indicating  a  compound  substance.  Thus,  if 
we  allude  to  the  letter  or  letters  indicating  an  clement,  we  say  its  symbol ;  but  if  we  are 
speaking  of  a  compound,  we  say  its  formula.  The  symbols  of  all  the  elements  will  be  found 
under  the  head  of  "Elements,"  vol.  i.  In  constructing  formuloe  there  are  several 
rules  to  be  observed,  the  neglect  of  which  will  lead  to  njisapprehension  of  the  meaning  in- 
tended to  be  conveyed.  Substances  in  the  most  intimate  union  are  expressed  by  placing 
the  symbols  in  juxta-position.  Thus,  oxide  of  lead  is  represented  by  PbO,  diy  sulphuric 
acid  by  SO^,  acetic  acid  by  C^H■'0^  But  where  a  compound  is  to  be  expressed  which  is 
itself  formed  by  tlie  union  of  two  compounds  of  the  class  first  mentioned,  such  as  an  acid 
and  a  base,  a  comma  is  placed  between  them  thus  :  Sulphate  of  lead  is  PbO,SO\  nitrate  of 
copper  CuO,NO^.  The  number  of  atoms,  when  more  than  one  enters  into  a  compound,  is 
expressed  by  writing  the  number  on  the  upper  part  of  the  right  hand  of  the  element.  But 
if  only  one  atom  is  to  be  expressed,  the  mere  symbol  is  written.  Thus,  oxide  of  copper  is 
CuO,  but  the  sub-oxide  is  Cu'^0.  If  it  be  intended  to  multiply  a  formula  not  containing  a 
comma  or  other  sign,  such  as  SO',  C^IPO'',  &c.,  the  numlier  is  to  be  written  on  the  left 
hand  of  the  formula,  and  is  to  be  made  larger  than  would  be  the  case  if  it  merely  multiplied 
the  atoms  of  an  element.  Thus,  two  atoms  of  oxide  of  lead  are  written  2P1)0,  three  atoms 
of  acetic  acid,  SCIPO'.  But  it  is  to  be  remembered  that  a  number  placed  on  tlic  left  hand 
of  a  symbol  or  formula  only  multiplies  as  far  as  the  first  comma  or  sign,  so  that,  if  we  wish 
to  multiply  a  formula  containing  a  comma  or  other  sign,  the  formula  must  be  placed 
between  parentheses.  Thus,  two  atoms  of  sulphate  of  lead  are  written  2(PbO,SO').  If  it 
be  intended  to  express  the  f;ict  that  one  substance  is  to  be  added  to  another,  with  a  view  to 
the  production  of  a  given  compound  or  reaction,  the  substances  to  be  added  together  are 
connevted  by  a  plus  sign.  For  example,  suppose  it  be  necessary  to  express  the  fact  that 
one  equivalent  of  oxide  of  lead  added  to  one  equivalent  of  sulphuric  acid  produces  sulphate 


CHEMICAL  FORMULAE.  321 

of  lead,  we  write,  PbO  -f-  SO'  forms  sulphate  of  lead.  But  it  is  more  usual  and  brief  to  put 
down  the  terms  connected  by  the  plus  sign,  followed  by  the  sign  of  equality,  and  then  the 
formula  of  the  resulting  compound,  thus  : — PbO  -{-  SO'  =  PbO,SO'.  A  collection  of  symbols 
expressing  the  nature  of  a  reaction  or  decomposition,  the  two  terms  being  united  by  the 
symbol  of  equality,  is  called  an  equation.  Equations  are  of  the  highest  value  to  the 
chemist,  as  enabling  him  to  express  in  the  simplest  possible  manner  the  most  complicated 
reactions.  Moreover,  these  equations  enable  us  to  see  at  a  glance  the  true  nature  of  a  de- 
composition. To  take  a  simple  case,  namely,  that  of  the  decomposition  of  terchloride  _of 
antimony  by  carbonate  of  ammonia,  we  have 

SbCl^  +  3  (NH^O,CO^)  =  SbO'  +  SXH^Cl  +  SCO'. 

Or,  in  words,  terchloride  of  antimony  plus  three  equivalents  of  carbonate  of  ammonia, 
yields  one  equivalent  of  teroxide  of  antimony,  three  equivalents  of  chloride  of  ammonium, 
and  three  equivalents  of  carbonic  acid. 

The  above  illustrations  will  suffice  to  show  the  principles  upon  which  formulae  and 
equations  expressive  of  chemical  decompositions  are  constructed.  In  writing  equations 
showing  the  metamorphoses  of  substances  with  which  it  may  be  supposed  the  reader  of 
them  may  not  be  very  fully  acquainted,  it  is  proper  to  place  beneath  them  the  names  of  the 
substances  in  full ;  thus,  in  writing  the  change  supposed  to  be  experienced  by  amygdaline 
under  the  influence  of  a  ferment  which  does  not  itself  contribute  any  substance  to  the  reac- 
tion, we  might  say  : — 

C^''H"NO"   4-  4H0    =    C^H^O^  -f-   C=NH   -\-  2C"H"0" 

Amygdaline.  Bitter  al-       Prussic      Grape  sugar, 

mond  oil.         acid. 
la  writing  the  formulae  ©rsubstitution  compounds,  it  is  convenient  to  place  the  replaced 
and  replacing  substances  in  a  vertical  line,  so  as  at  a  glance  to  indicate  the  substitution 
which  has  taken  place.     As  an  illustration,  we  shall  place  side  by  side  the  chemical  type 
ammonia  and  some  bodies  derived  from  it  by  substitution. 

(  II  (  CTI'  (  C=H«  ( C^H^  ( C'=H»  ( pt  (  C^n^ 

N-^H  N-^     H        N-^C'^H'       N.|C-H'      N -^       H        N -^  pt  P.^C=IP 

(H  (II  I     H  (cm^  (      H  (11  (C=U« 

Ammonia.  Methylamiue.  Bimethy-     Trimethy-       Anihne.       Platina-    Triphosphme- 
lamine.  lainine.  mine.         thylamine. 

In  the  first  of  the  above  formula?  we  have  the  type  or  starting  point,  ammonia  itself.  In 
the  next  we  find  one  atom  of  hydrogen  (two  volumes)  replaced  by  one  atom  (two  volumes) 
of  the  radical  methyle.  In  the  third  we  find  two  atoms  of  hydrogen  replaced  ;  and  in  the 
fourth  illustration  all  three  have  been  replaced  by  methyle.  The  fifth  formula  is  that  of 
ammonia,  in  which  one  equivalent  of  hydrogen  is  replaced  by  phenyle,  forming  phenyla- 
mine,  or,  as  it  is  more  usually  termed,  aniline.  The  sixth  illustrates  a  very  peculiar  substitu- 
tion. In  it  we  find  two  atoms  of  hydrogen  replaced  by  the  platinicum  of  the  late  illustrious 
chemist,  M.  Gerhardt,  who  regards  platinum  as  entering  into  substitutions  with  two  atomic 
weights,  as  if  it  were  two  metals.  The  one  being  the  platinum  of  chemists  generally,  its 
atomic  weight  being  99,  (and  its  symbol  Pt ;)  this  he  calls  platinosum.  The  other  being 
platinicum,  (pt,)  with  an  atomic  weight  half  t^at  of  platinosum,  namely,  49-5.  The  last 
formula  is  that  of  the  singular  base,  triphosphmethylamine.  In  it  we  see  the  nitrogen  of 
the  original  type  replaced  by  phosphorus,  and  each  equivalent  of  hydrogen  by  methyle. 

It  is  a  fruitful  source  of  annoyance  to  students  and  others  to  find,  on  looking  through 
chemical  works,  the  same  substance  represented  by  different  authors  with  totally  different 
formulae.  We  shall  endeavor  to  give  a  few  instances  and  such  explanations  as  will  assist  in 
enabling  the  student  to  overcome  the  difficulty.  It  is  often  the  case  that  the  differences  in 
the  formulae  arise  from  the  works  consulted  having  been  written  at  different  dates ;  the 
older  one  is  then,  in  most  cases,  to  be  rejected,  because  it  is  probable  that  the  formuke  in  it 
have  been  corrected  by  subsequent  and  more  accurate  researches.  It  not  unfrequently 
happens  that  an  author  writes  nitrous  acid  NO*,  and  the  true  nitrous  acid  (NO')  is  called 
hyponitrous  acid.  It  may  serve  to  assist  the  student  in  correcting  any  errors  on  this  point, 
to  consult  a  list  of  the  oxides  of  nitrogen  according  to  the  nomenclature  at  present  cm- 
ployed  ;  for  which,  see  some  standard  work  on  chemistry.  A  still  more  conmion  cause  of 
difficulty  is  owing  to  the  different  theoretical  views  of  chemists  regarding  the  constitution 
of  chemical  substances.  The  papers  of  MM.  Laurent  and  Gerhardt,  and  the  more  advanced 
of  their  followers,  are  at  times  almost  unintelligible  to  the  beginner,  owing  to  their  adoption 
of  different  atomic  weights  to  those  employed  in  this  country.  Whatever  opinion  maybe 
held  by  individuals  respecting  the  necessity  for  the  changes  adopted  by  them,  it  must  be  re- 
membered that  the  arguments  in  favor  of  their  doctrines  are  in  general  of  the  most  weighty 
kind  ;  and,  moreover,  that  chemical  reactions  can  often  be  explained  and  generalized  when 
Vol.  III.— 21 


822  CHEMICAL  FOEMUL^. 

seen  through  the  medium  of  their  theoretical  views,  which  present  exceedingly  embarrassing 
points  if  viewed  under  the  old  system.  It  will  serve,  to  a  great  extent,  to  remove  the  diffi- 
culties alluded  to,  if  it  be  remembered  that,  in  order  to  pass  from  the  ordinary  atomic 
weights  used  in  this  work  to  those  employed  by  M.  Gerhardt,  it  is  merely  necessary  to 
double  the  atomic  weights  of  carbon,  oxygen,  sulphur,  and  selenium,  while  the  hydrogen, 
nitrogen,  phosphorous  metals,  chlorine,  bromine,  iodine,  and  fluorine  remain  unaltered. 

Some  of  the  more  advanced  chemists  of  the  present  day  write  carbonic  acid  CO*,  instead 
of.  CO''.  This  is  in  consequence  of  their  regarding  it  as  a  bibasic  instead  of  a  monolwsic 
iicid.  The  same  thing  applies  to  sulphuric  acid.  It  is  also  to  be  remembered  that  most 
modern  chemists  assume  organic  bodies  to  undergo  a  condensation  to  four  volumes ;  conse- 
quently, ether  becomes  CH'^'O^,  instead  of  C^H^O.  The  same  remark  applies  to  many 
other  substances.  Bodies  that  cannot  have  their  vapor  relations  properly  studied,  in  conse- 
quence of  their  not  being  volatile  without  decomposition,  are  often  written  in  two  or  three 
different  ways  by  various  authors.  It  is  probable  that  these  anomalies  will,  for  a  time,  in- 
crease rather  than  diminish,  because  recent  discoveries  are  constantly  showing  the  inade- 
quacy of  the  older  views  of  the  chemical  constitution  of  bodies  to  explain  the  reactions  that 
occur. 

It  will  greatly  assist  the  student  in  his  endeavors  to  recollect  chemical  formulae,  if  he 
commits  to  memory  the  principal  types  and  the  substances  which  are  regarded  as  formed  on 
their  model.     The  following  are  those  which  are  best  established  : — 

Type,  two  atoms  of  water. — This  type  is  written  in  such  a  manner  that  the  replacement 
of  the  hydrogen  can  be  distinctly  seen.  By  its  side  are  placed  a  few  of  the  substances 
formed  on  the  same  model. 

Two  atoms  Hydrate  of     Anhydrous 

of  water.  Acetic  acid.  Alcohol.  Ether.*  _  potash.  potash. 


O^j 


H  '^  ^      H  ^  \  CIV 


In  the  above  simple  illustrations  of  the  type  water  we  have,  in  the  case  of  acetic  acid, 
one  atom  of  hydrogen  replaced  by  the  oxidized  radical  acetyle  CHW,  and  the  other  by  one 
atom  of  basic  hydrogen.  By  basic  hydrogen  is  meant,  that  it  acts  the  part  of,  and  can  be  re- 
placed by,  a  metal.  The  opinions  of  chemists  with  regard  to  the  nature  of  the  radical  exist- 
ing in  acetic  acid  are  divided.  Some  consider  the  acid  as  the  hydrated  teroxide  of  the  non- 
oxidized  radical  acetyle,  (C*H^,)  and  therefore  write  its  formula  C^H^O'  -|-  HO.  But  as  the 
chloride  of  the  oxidized  radical  can  be  isolated,  we  cannot  doubt  its  existence.  Moreover, 
there  is  no  doubt  of  the  existence  of  the  other  radical,  C^H',  because  we  find  it  replacing 
hydrogen  in  the  base  acetylamine.  But  the  conclusion  must  be  drawn  from  these  facts 
that  there  are  two  radicals,  one  existing  in  acetic  acid,  C*IPO^,  which  Williamson  calls 
othyle ;  and  another,  sometimes  called  vinyle,  C*H^,  which  exists  in  aldehyde,  in  olcfiant 
gas,  and  several  other  bodies.     The  radical  in  acetic  acid  is,  consequently,  not  CIl^,  but 

The  next  illustration  is  that  of  alcohol,  which  consists  of  two  atoms  of  water,  in  which 
one  atom  of  hydrogen  is  replaced  by  ethyle,  and  the  other  by  hydrogen.  Ether,  on  the 
other  hand,  is  derived  from  the  same  type,  both  atoms  of  basic  hydrogen  being  replaced  by 
ethyle.  Hydrate  of  potash  and  anhydrous  potash  will,  after  what  has  been  said,  explain 
themselves.  It  will  be  seen  that  in  all  these  illustrations,  the  same  vapor  volume  is  pre- 
served, and  by  this  means  the  exceeding  anomaly  of  ether  and  alcohol  being  of  diflerent 
vapor  volumes  is  removed.  While  the  type  two  atoms  of  water  (=4  volumes)  has  an  ac- 
tual existence,  it  remains  for  chemists  to  discover  whether  we  are  justified  in  receiving  as 
types  bodies  which  have  no  real  existence,  such  as  three  atoms  of  water. 

Tjipe,  two  atoms  of  hydroc/en. — The  type  ammonia  has  already  been  sufficiently  illus- 
trated ;  it  remains,  then,  only  to  show  what  substances  are  to  be  regarded  as  formed  on  the 
type  hydrogen.  M.  Gerhardt,  in  addition  to  these,  adopts  hydrochloric  acid  as  a  type  ;  but 
when  we  consider  that  that  acid  is  itself  formed  on  the  hydrogen  model,  it  appears  unneces- 
sary to  raise  it  to  the  dignity  of  a  separate  type. 

Two  atoms  of        Olcfiant  Marsh       Hydrochloric  Prussic  Chloride 

hydrogen.  gas.  gas.  acid.  Benzole.         acid.  of  ethyle. 

H  C'H=  C-H^  CI  C-H^  CN 

H  H  H  H  H  H 

The  above  will  be  sufficiently  plain  after  what  has  been  said,  it  being  remembered  that 
C-H^  is  methyle,  C'H*  ethyle,  C''H'  phenyle,  and  C^N  cyanogen. 

It  is  sometimes  a  source  of  perplexity  to  the  beginner  to  find  that  the  formula?  of  salts 
are  written  by  different  authors  in  a  somewhat  different  manner.     Thus,  sulphate  of  potash 

*  For  the  tj-pical  representation  of  the  mised  and  composed  ethers,  see  the  article  Ether. 


CHEMICAL  FORMULA. 


323 


will,  by  one,  be  written  SO^,KO,  and  by  another  SO'E.  The  reason  of  this  will  become 
plain  from  the  following  considerations  : — All  salts  are  derived  from  acids  by  the  substitu- 
tion of  metals  for  hydrogen.  Thus, 'if  instead  of  writing  sulphuric  acid  SO^,HO  we  write 
SO*H,  we  shall  at  once  see  that  sulphate  of  potash,  SO'K,  is  sulphuric  acid  in  which  one 
equivalent  of  hydrogen  is  replaced  by  potassium.  It  is  true  that  the  relation  between  acids 
and  salts  may  be  more  completely  seen  by  using  a  different  class  of  formula?,  founded  on 
the  theory  of  types ;  but,  nevertheless,  the  above  illustrations  will  serve  to  explain  why  one 

person  will  write  acetate  of  potash      g-      '    another       V.  '  ^  X.\iiviii  C'IPO^,KO,  and 

perhaps  a  fourth  C<H=0-,KO*. 

On  the  modes  of  determining  the  empirical  and  ratioiial  formula  of  substances  from  the 
results  of  their  analysis. — It  now  remains  to  show  how  the  formula;  of  bodies  are  deter- 
mined. There  are  two  kinds  of  formulas — the  empirical  and  rational.  An  empirical  for- 
mula merely  indicates  the  simplest  ratio  existing  between  the  elements  present ;  a  rational 
formula  shows  the  absolute  constitution  of  an  atom  or  equivalent  of  any  substance.  Some- 
times the  expression  rational  formula  is  used  in  a  more  extended  sense,  and  then  signifies 
the  actual  manner  in  which  the  elements  are  arranged  in  a  compound  molecule,  but  this 
happens  so  seldom,  that  we  shall  in  this  work  understand  the  term  in  the  sense  first  given. 

An  empirical  formula  can  always  be  deduced  from  the  mere  result  of  an  accurate  analy- 
sis. A  rational  formula,  on  the  other  hand,  demands  a  knowledge  of  the  atomic  weight  of 
the  substance.  The  latter  datum  can  be  best  determined — 1st,  by  the  analysis  of  a  com- 
pound with  a  substance  the  atomic  weight  of  which  is  well  established  ;  2d,  by  determining 
the  density  of  its  vapor. 

Empirical  formidm. — The  percentage  composition  of  a  compound  having  been  accu- 
rately found,  the  empirical  formula  may  be  deduced  from  the  following  rule  : — Divide  the 
percentage  of  each  constituent  by  its  atomic  weight,  and  reduce  the  number  so  obtained  to 
its  lowest  terms.  Suppose,  for  example,  the  empirical  formula  of  nitric  acid  to  be  required, 
the  composition  being  : — 

Nitrogen    -        -     25-9 
Oxygen      -        -    '74'1 

100-00 
These  numbers,  divided  by  their  respective  atomic  weights,  give: — 

25-9 

IT  =  '-'' 

741 

—  =.9-26 

To  reduce  these  numbers  to  their  lowest  terms,  it  is  merely  necessary  to  divide  9  "26  by 
1*85.     The  simplest  terms  being  : — 

Nitrogen,  1-00:  Oxygen,  5-00. 

Nitric  acid  consequently  consists  of  one  equivalent  of  nitrogen  and  five  of  oxygen. 

Rational  formula. — In  the  above  illustration  we  found  the  simplest  ratio  existing  be- 
tween the  elements  of  nitric  acid.  But  it  will  be  seen  that,  for  aught  that  appears  there,  it 
may  consist  of  n  times  N0\  It  becomes  necessary,  therefore,  to  find  the  atomic  weight  of 
the  acid,  and  then  to  find  the  number  of  atoms  of  the  elements,  (combined  in  the  above 
ratio,)  which  will  make  that  atomic  weight.  In  order  to  do  this,  it  will  be  proper  to  deter- 
mine the  atomic  weight  of  the  acid  from  the  data  procured  by  the  first  method,  given  above. 
In  order  to  accomplish  this,  a  salt  was  analyzed  for  the  percentages  of  soda  and  nitric  acid, 
with  the  annexed  result : — 

Soda        -        -        -        36-47 
Nitric  acid       -        -        63-53 


100-00 
The  required  datum,  namely,  the  atomic  weight  of  the  acid,  can  easily  be  obtained  by 
saying, — As  the  percentage  of  ba'^e  is  to  the  percentage  of  acid,  so  is  the  atomic  ircight  of 
ffie  base  to  the  atomic  weight  of  the  acid.     In  the  instance  given  we  have,  therefore  :— 

36-47  :  63-53  ::  31  :  63-999 


Percentage  of 
base. 


Percentage  of 
acid. 


Atomic  weight  of 
base. 


Atomic  weight  of 
acid. 


It  is  evident  that  53-999  may  be  written  54-0  without  any  inaccuracy.  If,  therefore, 
we  add  together  the  equivalents  of  nitrogen  and  oxygen  in  the  ratio  found  in  the  empirical 
formula,  we  shall  have : — 


324  CHICORY. 

1  equivalent  of  nitrogen  =  14 

5  equivalents  of  oxygen  =  40  * 

54  =  the  atomic  weight  of  the  acid. 
We  will  now  consider  the  mode  of  determining  the  rational  formula  of  a  substance  from 
the  results  of  the  analysis  and  the  density  of  the  vapor.     Suppose  a  hydrocarbon  to  have 
yielded  on  analysis  : — 

Carbon      -         -         -         85-'714 
Hydrogen  -         -         14-286 


100-000 


85-714  14-286       ,     „ 

And—  — -—  =  14-280  — -—  =  14-286 

6  1 

The  quotient  being  the  same,  the  empirical  formula  becomes  C"H°.  It  remains,  there- 
fore, to  determine  the  value  of  n.  The  density  of  the  vapor  was  found  to  be  2-9064.  Now, 
the  hydrocarbons  always  possess  a  condensation  to  four  volumes. 

For  four  volume  formulas  the  rule  is: — Divide  the  density  of  the  gas  by  half  the  den- 
sity of  hydrogen.     Applying  this  rule,  we  have : — 

2-9064 
^„,     =  84-00 
•0346 

It  is,  therefore,  necessary  to  find  what  multiple  of  the  atomic  weight  of  CH  will  make 
8400.  Now  C  -|-  H  =  6  -f"l  =  7,  and  7x12  =  84.  Consequently  the  formula  is  12(CH,) 
or,  as  it  is  always  written,  C'"H'^ 

The  above  rules  will  suffice  to  enable  any  person  to  determine  the  empirical  and  rational 
formulae  of  substances  from  the  results  of  analysis. — C.  G.  W. 

CHICORY.  The  root  of  the  Cichorium  intybus.  Wild  Succory  or  Chicory.  This  plant 
is  cultivated  in  various  parts  of  England,  growing  well  in  a  gravelly  or  chalky  soil ;  also  in 
Belgium,  Holland,  Germany,  and  France.  The  roots  of  the  wild  succory  were  formerly  used 
medicinally ;  it  possesses  properties  in  many  respects  resembling  those  of  the  dandelion, 
but  it  is  rarely  employed  for  curative  purposes  in  the  present  day. 

Chicory  root  roasted  has  been  employed  as  a  substitute  for  coffee  for  more  than  eighty 
years.  [Constantirii  Kachricht  von  d.  Cichorianicurzel,  1771.)  It  is  now  employed  ex- 
tensively as  a  mixture  with  coffee,  which,  although  allowed,  cannot  be  regarded  other  than 
an  adulteration. 

Chicory  root  is  heated  in  iron  cylinders,  which  are  kept  revolving  as  in  the  roasting  of 
coffee.  In  this  country  about  two  pounds  of  lard  are  added  to  every  cwt.  of  chicory  during 
the  roasting  process  ;  in  France  butter  is  used  ;  by  this  a  lustre  and  color  resembling  that 
of  coffee  are  imparted  to  it.  When  roasted,  the  chicory  is  ground  to  powder  and  mixed  with 
the  coffee.  Chicory  has  been  supposed  by  some  persons  to  be  wholesome  and  nutritive, 
while  others  contend  that  it  is  neither  one  nor  the  other ;  however,  no  obvious  ill  effects 
have  been  observed  to  arise  from  its  employment,  if  we  except  the  occasional  tendency  to 
excite  diarrhoea,  when  it  has  been  used  to  excess.  The  analysis  of  chicory  root  by  John 
gave  25  parts  watery  hitter  extractive,  3  parts  resin,  besides  sugar,  sal  avnnoniac,  and 
woody  fbre.  Waltl  procured  inulin  from  it,  but  the  quantity  varies  greatly  in  different 
roots.     The  following  remarks  on  the  adulteration  of  chicory  are  by  Dr.  Pereira. 

"  Roasted  chicory  is  extensively  adulterated.  To  color  it,  Venetian  red  and,  perhaps, 
reddle  are  used.  The  former  is  sometimes  mixed  with  the  lard  before  this  is  introduced 
into  the  roasting  machine  ;  at  other  times  it  is  added  to  the  chicory  during  the  process  of 
grinding.  Roasted  pulse,  (peas,  beans,  and  lupines,)  corn,  (rye  and  damaged  wheat,)  roots, 
(parsnips,  carrots,  and  mangold  wurzel,)  bark,  (oali-bark  tan,)  wood  dust,  (logwood  and 
mahogany  dust,)  seeds,  (acorns  and  horse  chestnuts,)  the  marc  of  coffee,  coffee  husks, 
(called  coffee-flights,)  burnt  sugar,  baked  bread,  dog  biscuits,  and  baked  livers  of  horses 
and  bullocks,  (!)  are  substances  which  are  said  to  have  been  used  for  adulterating  chicory. 
A  mixture  of  roasted  pulse  (peas  usually)  and  Venetian  red  has  been  used,  under  the  name 
of  Hambro'  potrder,  for  the  same  purpose. 

"  The  following  are  the  chief  modes  of  examining  chicory  with  the  view  to  the  detection 
of  these  adulterations  : — 

"  1st.  Careful  examination  of  the  odor,  flavor,  and  appearance  to  the  naked  eye  of  the 
suspected  powder.     In  this  way  foreign  substances  may  sometimes  be  detected. 

"  2d.  A  portion  of  the  dried  powder  is  to  be  thrown  on  water ;  the  chicory  rapidly  imbibes 
the  water  and  falls  to  the  bottom,  whereas  some  intermixed  powders  (as  the  marc  of  coffee) 
float. 

"  3d.  The  suspected  powder  is  to  be  submitted  to  careful  microscopical  examination. 
pulse  and  corn  may  be  detected  by  the  size,  shape,  and  structure  of  the  starch  grains.    The 


CHLORIDE.  325 

tissues  of  bark,  woods,  and  other  roots  may  also  be  frequently  distinguished  from  those  of 
chicory. 

"  4th.  A  decoction  of  the  suspected  chicory  is  then  to  be  prepared,  and,  when  cold,  to 
be  tested  with  solution  of  iodine  and  persulphate  of  iron. 

"  Iodine  colors  a  decoction  of  pure  chicory  brownish  ;  whereas  it  produces  a  purphsh, 
bluish,  or  blackish  color  with  decoctions  of  roasted  pulse,  roasted  corn,  baked  bread,  roasted 
acorns,  and  other  substances  containing  starch.  Persulphate  or  perchloride  of  iron  does 
not  produce  much  effect  on  a  decoction  of  pure  chicory,  but  it  communicates  a  bluish  or 
blackish  tint  to  a  decoction  of  oak- bark,  of  roasted  acorns,  and  other  substances  containing 
tannic  or  gallic  acids. 

"  5  th.  By  incineration,  pure  dried  chicory  yields  from  4  to  5  per  cent,  of  a  gray  or 
fawn-colored  ash.  If  Venetian  red,  or  any  other  earthy  or  mineral  substances,  be  present, 
a  larger  amount  of  ash  is  obtained.  Moreover,  when  Venetian  red  has  been  employed,  the 
color  of  the  ash  is  more  or  less  red." 

CHINA  CLAY.  Kaolin,  or  Pohcelain  Clay,  WuWi  sec.  A  fine  white  clay  produced 
by  the  decomposition  of  the  felspar  of  the  granite  rocks.  It  is  found  and  prepared  in  this 
country  in  Cornwall  and  Devonshire. 

CHINA  STONE.  A  semi-decomposed  granite,  {Pctuntze,)  which  has  nearly  the  same 
composition  as  the  China  clay,  (see  Porcelain  Clay.)  "  Indeed,  the  China  clay  can  be 
considered  as  little  more  than  this  granite  in  a  more  advanced  state  of  decomposition." — 
De  la  Beche. 

The  China  stone  is  a  kind  of  granite,  the  felspar  of  which  has  undergone  a  partial 
decomposition.  It  is  carefully  selected  so  as  to  be  entirely  free  from  schorl,  and  requires 
no  other  preparation  for  the  market  than  to  be  broken  into  a  size  convenient  for  carriage. 
This  granite  is  of  a  peculiar  nature ;  it  does  not  contain  any  mica,  but  numerous  glossy 
scales  of  greenish-yellow  talc.  It  has  been  stated  by  some  authors  that  "  this  rock,  {Pegma- 
tite or  Graphic  granite,)  after  exposure  to  the  decomposing  action  of  the  weather,  is  the 
chief  source  "  of  the  China  stone  and  clay.  This  represents  but  very  imperfectly — indeed, 
incorrectly — the  conditions.  The  decomposition  of  the  granite  is  not  brought  about  by  the 
action  of  the  weather,  but  by  some  peculiar  decomposition  proceeding  to  a  considerable 
depth  through  the  whole  mass.  In  many  places,  from  the  very  surface  to  the  depth  of  more 
than  100  feet,  this  decomposition  is  equally  apparent ;  and  possibly  it  extends  to  much 
greater  depths  in  some  places.  The  same  stone  exposed  to  the  air  does  not,  in  .any  ordinary 
time,  exhibit  any  signs  bf  disintegration.  No  satisfactory  explanation  has  yet  been  offered 
of  the  conditions  under  which  granite  is  decomposed  to  produce  the  Kaolin  and  the  China 
stone. 

There  was  an  agreement  existing  amongst  the  producers  of  China  stone  to  send  off 
annually  only  12,000  tons;  but  when  the  demand  is  brisk,  this  has  been  extended  to 
18,000  tons,  and  sometimes  even  more.  The  value  of  the  China  stone  at  the  works  in 
Cornwall  is  annually  about  £1,800.  The  whole  that  is  raised  is  sent  to  the  Staffordshire 
potteries. 

CHLORIC  ACID.  This  acid,  which  is  only  known  in  combination  with  one  equivalent 
of  water,  is  exceedingly  unstable,  being  instantly  decomposed  by  contact  with  organic  mat- 
ter ;  undergoing  gradual  spontaneous  decomposition  in  diffused  daylight,  and  being  instantly 
decomposed,  at  a  temperature  of  a  little  above  100"  F.,  into  chlorine,  oxygen,  and  perchlo- 
ric acid,  the  two  former  escaping  as  gases.  It  is  prepared  by  decomposing  chlorate  of  pot- 
ash by  the  addition  of  hydrofluosilicic  acid,  which  forms  with  potash  an  insoluble  com- 
pound. 

CHLORINE,  one  of  the  most  energetic  of  the  undecomposed  substances,  exists,  under 
ordinary  circumstances,  as  a  greenish-yellow  gas ;  but,  when  exposed  to  a  pressure  of  4  atmos- 
pheres, it  becomes  a  transparent  liquid,  which  remains  unfrozen  even  at  the  cold  of-^220^ 
F.  In  the  first  state,  its -density,  compared  to  air,  (reckoned  1-000,)  is  2-47;  in  the 
second,  its  density,  compared  to  water,  (rOOO,)  is  1-33.  It  is  obtained  cither  by  the  action 
of  sulphuric  acid  on  a  mixture  of  common  salt  and  binoxide  of  manganese,  or  by  the  action 
of  moderately  strong  hydrochloric  acid  on  binoxide  of  manganese  alone.  In  the  first  case, 
the  proportions  are  7  parts  by  weight  of  oil  of  vitriol,  previously  diluted  with  1  parts  of 
water  and  4  parts  of  common  salt,  intimately  mixed  with  3  parts  of  binoxide  of  manganese; 
in  the  latter,  which  is  the  most  convenient  method,  hydrocliloric  acid,  specific  gravity  1-15 
is  gently  heated  with  the  finely  powdered  binoxide,  in  the  proportions  of  about  3  oz.  of 
oxide  to  half  a  pint  of  acid.  The  hydrochloric  acid  should  not  be  more  diluted  than  above 
indicated,  otherwise  an  explosion  may  occur,  probably  in  consequence  of  the  formation  of 
one  of  the  explosive  oxides  of  chlorine.  The  gas  must  be  collected  cither  over  brine  or 
over  warm  water. 

In  fumigating  the  MilUiank  Penitentiary,  Jfr.  Faraday  found  that  a  mixture  of  one  part 
of  common  salt  and  I  part  of  binoxide  of  manganese,  when  acted  upon  by  two  parts  of  oil  of 
vitriol  previously  mixed  witli  one  part  of  water,  (all  by  weight,)  and  left  till  cold,  produced 
the  best  results.     Such  a  mixture  at  60",  in  shallow  pans  of  red  earthenware,  liberated  its 


326  CHLORIDE  OF  LIME. 

chlorine  gradually,  but  perfectly,  in  four  days.  The  salt  and  manganese  were  well  mixed, 
and  used  in  charges  of  3^  pounds  of  the  mixture.  The  acid  and  water  were  mixed  in  a 
wooden  tub,  the  water  being  put  in  first,  and  then  about  half  the  acid  ;  after  cooling,  the 
other  half  was  added.  The  proportions  of  water  and  acid  were  9  measures  of  the  former  to 
10  of  the  latter. 

In  the  year  1846,  Mr.  Pattinson  patented  an  improved  mode  of  manufacturing  chlorine. 
In  this  process  he  made  use  of  a  stone  vessel  or  generator,  enclosed  in  a  double  iron  vessel. 
The  hydrochloric  acid,  specific  gravity  1'16,  is  poured  into  the  generator,  and  on  a  grating 
or  false  bottom  is  placed  the  binoxide  of  manganese  in  lumps.  The  temperature  of  the  con- 
tents of  the  generating  vessel  is  then  raised  to  180"  F.,  by  means  of  steam,  made  to  circu- 
late between  the  stone  vessel  and  the  iron  casing.  This  heat  is  continued  for  about  18 
hours,  and  then,  by  means  of  a  suitable  pipe  passing  to  the  bottom  of  the  generator,  steam, 
under  a  pressure  of  10  lbs.  to  the  inch,  is  injected  into  the  vessel  for  about  two  minutes, 
and  this  is  repeated  every  half  hour  for  about  six  hours.  In  this  process  no  mechanical  agi- 
tation is  required,  as  the  steam  enters  with  sufficient  force,  under  the  pressure  above  men- 
tioned, to  effect  the  requisite  agitation  of  the  contents,  and,  by  clearing  the  lumps  of 
manganese  from  all  adhering  matters,  expose  a  fresh  surface  continually  to  the  action  of 
the  acid. 

In  carrying  this  process  into  practical  operation,  Mr.  Pattinson  found  that  the  apparatus 
is  liable  to  be  completely  deranged,  and  the  iron  vessel  destroyed  by  the  action  of  the 
hydrochloric  acid,  if  the  stone  generating  vessel  should  happen  to  get  broken  ;  to  obviate 
which  inconvenience,  and  to  enable  the  generator  to  be  used  though  in  a  broken  condition, 
the  inner  iron  vessel  is  perforated ;  and  the  spaces  between  the  two  iron  vessels,  and 
between  the  inner  iron  vessel  and  the  stone  generator,  are  filled  with  coal  tar,  or  pitch, 
thickened  by  boiling  to  such  a  consistence  as  to  be  tough,  but  not  brittle,  when  cold. 
Steam,  circulating  through  a  coil  of  pipe  passing  between  the  iron  vessels,  serves  to  maintain 
the  tar  at  the  requisite  degree  of  heat ;  and  in  the  event  of  the  breakage  of  the  stone  gener- 
ator, the  liquified  tar  flows  into  the  fissure,  and  prevents  the  escape  of  the  hydrochloric 
acid  into  the  steam  vessel. 

A  method  of  treating  the  residuum  obtained  in  the  manufacture  of  chorine  was  patented 
in  185.5  by  Mr.  C.  Tennant  Dunlop.  It  consists  in  transforming  the  chloride  of  manganese, 
first  into  carbonate  and  then  into  oxide,  by  the  action  of  heat.  AVhatever  impurity  the 
cliloride  of  manganese  may  contain — as  chloride  of  iron,  for  instance — is  first  separated, 
either  by  calcination  or  by  the  agency  of  a  suitable  precipitant.  Practical  working  has 
shown  that  the  carbonate  of  manganese  thus  treated  yields  an  oxide  of  a  richness  equivalent 
to  that  of  80  per  cent,  pure  peroxide.  The  carbonate  of  manganese  may  be  obtained  by 
precipitation  from  the  chloride  by  carbonate  of  ammonia.  The  chloride  of  ammonium  re- 
sulting from  this  treatment  may  either  be  employed  as  such,  or  it  may  be  re-transformed  in 
the  usual  way  into  carbonate  for  the  precipitation  of  fresh  chloride  of  manganese.  Hydrate 
of  lime  is  also  used  as  a  precipitant,  tlie  resulting  hydrated  oxide  of  manganese  being  sub- 
sequently converted  into  carbonate  by  the  Iransmission  through  it  of  a  stream  of  carbonic 
acid. 

By  another  process,  carbonate  of  manganese  is  obtained  by  passing  carbonic  acid 
through  the  solution  of  chloride  of  manganese  which  has  been  previously  mixed  with  a 
quantity  of  carljonate  of  soda.  The  carbonate  of  soda,  under  the  influence  of  carbonic  acid, 
decomposes  the  chloride  of  manganese  into  carbonate,  from  which  the  oxide  can  be  obtained. 
The  essential  feature  of  this  invention  is  the  production  of  artificial  oxide  of  manganese,  by 
first  converting  the  chloride  into  carbonate,  and  afterwards  this  latter  into  oxide,  by  the 
joint  agencies  of  heat  and  atmospheric  air. 

CHLORIDE  OF  LIME.  Mr.  Graham  found  that  hydrate  of  lime,  dried  at  212°,  absorbed 
afterwards  little  or  no  chlorine ;  but  that,  when  dried  over  sulphuric  acid,  it  was  in  the 
most  favoraljle  condition  for  becoming  chloride  of  lime.  A  dry,  white,  pulverulent  com- 
pound is  obtained  l)y  exposing  the  last  hydrate  to  chlorine,  which  contains  41  2  to  4r4 
cidorine  in  100  parts,  of  which  39  parts  are  available  for  bleaching,  the  remainder  going  to 
form  chlorine  of  calcium  and  chlorate  of  lime.  This  appears  to  be  the  maximum  absorption 
of  chlorine  by  dry  hydrate  of  lime ;  but  the  bleaching  powder  of  commerce  rarely,  even 
when  fresh  prepared,  contains  more  than  30  per  cent,  of  chlorine,  and  after  being  kept  for 
several  months,  the  proportion  often  falls  as  low  as  20  per  cent.  A  compound  containing 
one  equivalent  of  chlorine  and  one  equivalent  of  hydrate  of  lime,  should  contain  48'57 
chlorine  and  .t1'43  hydrate  of  lime;  a  compound  of  one  equivalent  of  chlorine  and  two  of 
hydrate  of  lime,  should  contain  32 '42  chlorine  and  67"58  hydrate  of  lime ;  and  these  are 
about  the  proportions  in  good  commercial  specimens.  It  would  not  be  advisable  to  attempt 
to  manufacture  a  more  highly  chlorinated  product,  as  the  stability  of  the  compound  is  in- 
creased by  an  excess  of  lime.  Where  a  stream  of  chlorine  is  transmitted  through  water 
holding  hydrate  of  lime  in  suspension,  the  lime  is  entirely  dissolved,  and  the  full  equivalent 
of  chlorine  is  absorl)ed.  Water  poured  upon  bleaching  powder  dissolves  out  the  bleaching 
t'ombination,  leaving  a  large  residue  of  lime.     Ten  parts  of  water  are  required  for  one  part 


CHLOROMETRY. 


327 


of  dry  chlorine.  The  solution  emits  the  peculiar  odor  of  hypochlorous  acid ;  and  if  we  re- 
gard bleaching  powder  as  hypochlorite  of  lime,  the  reaction  which  occurs  in  its  formation 
will  be  thus  represented  : — 

2CaO+2Cl= CaCl+CaO,C10. 

But  good  bleaching  powder  is  not  deliquescent,  neither  does  alcohol  dissolve  anything  from 
it,  both  which  should  occur  if  the  compound  contained  free  chloride  of  calcium.  It  is 
possible,  however,  that  the  two  salts  may  exist  in  bleaching  powder  in  the  form  of  a  double 
salt,  or  that  the  chlorine  is  in  direct  combination  with  the  oxide.  If  the  compound  be  sup- 
posed to  be  pure  chloride  of  lime,  the  reaction  is  simply  an  absorption  of  chlorine  ;  and  the 
same  should  be  the  case  with  the  other  bleaching  compounds — chloride  of  soda,  for  instance. 
But  when  carbonate  of  soda,  saturated  with  chlorine  (Labarraque's  Liquor)  is  evaporated,  no 
chlorine  is  evolved,  and  the  residue  still  possesses  bleaching  properties.  The  true  nature  of 
bleaching  powder  is  open,  therefore,  to  speculation. 

The  bleaching  action  of  solution  of  chloride  of  lime  is  very  slow  unless  an  acid  be  added 
to  it.  When  dilute  sulphuric  acid  in  insufficient  quantity  is  employed,  no  chlorine  is 
evolved  but  hypochlorous  acid,  which  may  be  distilled  off  and  condensed  in  a  suitable  re- 
ceiver ;  but  with  excess  of  acid,  chlorine  only  is  liberated.  When  calicoes  and  other  woven 
goods  are  to  be  bleached,  they  are  first  thoroughly  cleansed  by  boiling  successively  with 
lime-water  and  a  weak  solution  of  caustic  soda ;  they  are  then  digested  in  a  solution  of 
bleaching  powder,  specific  gravity  r02,  containing  about  2^  per  cent,  of  chloride  of  lime; 
after  which  they  are  immersed  in  very  dilute  sulphuric  acid,  which,  by  liberating  the  chlo- 
rine within  the  fibres  of  the  cloth,  rapidly  removes  the  color.  The  goods  are  then  washed, 
a  second  time  steeped  in  alkali,  and  again  passed  through  a  weaker  solution  of  chloride,  and 
then  through  dilute  acid  ;  after  which  they  are  thoroughly  washed  in  water.  The  quantity 
of  liquor  necessary  for  700  lbs.  of  cloth  is  971  gallons,  containing  38Si  lbs.  of  chloride. 
When  white  figures  are  required  on  a  colored  ground,  tlie  pattern  is  printed  on  the  cloth 
with  tartaric  acid,  thickened  with  gum.  The  color  is  discharged  in  those  places  where  the 
acid  was  present,  but  elsewhere  untouched.  When  chloride  of  lime  is  heated,  it  evolves 
oxygen  gas,  and  sometimes  chlorine,  and  it  becomes  converted  into  a  mixture  of  chlorate  of 
lime  and  chloride  of  calcium,  which  has  no  bleaching  properties.  Half  an  ounce  of  chloride 
of  lime  boiled  in  two  ounces  of  water  yields,  according  to  Keller,  165  cubic  inches  of  oxygen 
contaminated  with  chlorine. 

The  property  of  chlorine  to  destroy  offensive  odors  and  to  prevent  putrefaction,  gives 
to  the  chlorides  of  lime  and  soda  a  high  value.  On  this  important  subject  Pereira  has  the 
following  remarks  (Mat.  Med.  vol.  I.)  with  reference  to  medical  police.  "If  air  be  blown 
through  putrid  blood,  and  then  through  a  solution  of  chloride  of  lime,  carbonate  of  lime  is 
precipitated,  and  the  air  is  disinfected  ;  but  if  the  air  be  first  passed  through  putrid  blood, 
then  through  caustic  potash,  or  milk  of  lime,  to  abstract  the  carbonic  acid,  and  afterwards 
through  the  solution  of  chloride  of  lime,  it  retains  its  stinking  quality.  Chloride  of  lime 
may  be  employed  to  prevent  the  putrefaction  of  corpses  previous  to  interment ; — to  destroy 
the  odor  of  exhumed  bodies  during  medico-legal  investigations  ; — to  destroy  bad  smells  and 
prevent  putrefaction  in  dissecting-rooms  and  workshops  in  which  animal  substances  are  em- 
ployed (as  catgut  manufactories  ;) — to  destroy  unpleasant  odors  from  privies,  sewers,  drains, 
wells,  docks,  &c.  ;  to  disinfect  ships,  hospitals,  prisons,  stables,  &c.  The  various  modes  of 
applying  it  will  readily  suggest  themselves.  For  disinfecting  corpses,  a  sheet  should  be 
soaked  in  a  pailful  of  water  containing  a  pound  of  chloride,  and  then  wrapped  round  the 
body.  For  destroying  the  smell  of  dissecting-rooms,  &c.,  a  solution  of  the  chloride  may 
be  applied  by  means  of  a  gardening  pot."  Of  equal  importance  is  this  substance  to  the 
medical  practitioner.  "  We  apply  them,"  observes  Pereira,  "  to  gangrenous  parts,  to 
ulcers  of  all  kinds  attended  with  foul  secretions  ;  to  compound  fractures  accompanied  with 
offensive  discharges ;  in  a  word,  we  apply  them  in  all  cases  accompanied  with  offensive  and 
fetid  odors.  Tlieir  efficacy  is  not  confined  to  an  action  on  dead  parts,  or  on  the  discharges 
from  wounds  and  ulcers  ;  they  are  of  the  greatest  benefit  to  living  parts,  in  which  they  in- 
duce more  healthy  action,  and  the  consequent  secretion  of  less  offensive  matters.  Further- 
more, in  the  sick  chamber,  many  other  occasions  present  themselves  on  which  the  power  of 
the  hypochlorites  to  destroy  offensive  odors  will  be  found  of  the  highest  value  :  as  to  coini- 
tcract  the  unpleasant  smell  of  dressings,  or  bandages,  &c.,  &c.  In  typhus  fever  a  handker- 
chief, or  a  piece  of  calico,  dipped  in  a  weak  solution  of  an  alkaline  hypochlorite,  and  sus- 
pended in  the  sick  chamber,  will  be  often  of  considera))le  service  both  to  the  patient  and  to 
the  attendants."  The  poisonous  exhalations  from  foul  sewers  may  be  coimteracted  by  a 
slight  inhalation  of  chlorine  ga.s,  as  obtained  from  a  little  chloride  of  lime  placed  in  the  folds 
of  a  towel  wetted  with  .acetic  acid. — II.  M.  N. 

CIILOROMETRY.  The  processes  or  series  of  processes  by  which  the  strength  or  com- 
mercial value  of  substances  containing  chlorine,  or  from  wliich  chlorine  may  be  rendered 
available,  is  ascertained,  is  called  Chloromctrij.  Cliloride  (hypochlorite)  of  lime,  of  potash, 
or  of  soda,  and  the  ores  of  manganese,  are  the  most  important  of  these  substances. 

Chloride  of  lime  is  a  mixture  of  hypochlorite  of  lime,  chloride  of  calcium,  and  hydrate 


328  CHLOROMETPwY. 

of  lime  (CaO,C10-{-CaCl  +  CaO,nO,)  and  is  decomposed  by  the  weakest  acids — even  by  car- 
bonic acid  ;  and  therefore,  by  exposure  to  the  air,  it  gradually  loses  its  chlorine,  and  being 
converted  into  carbonate  of  lime,  it  may  become  perfectly  valueless.  This  decompcsiiion 
by  all  acids  is  common  to  all  decolorizing  chlorides  (hypochlorites,)  and  may  be  explained, 
either  by  admitting  that  the  decomposing  acid  (say,  for  example,  the  carbonic  acid  of  the 
air)  simply  eliminates  the  hypochlorous  acid,  the  oxygen  of  which  oxidizes  in  a  direct 
manner  the  calcium  of  the  chloride  of  calcium  mixed  with  the  hypochlorite  of  lime,  thus  : — 

CaO,C10-f  CaCl+2CO-=2CaO,CO-4-2Cl ; 

or  by  considering  the  decolorizing  chloride  (chloride  of  lime,  for  example)  not  as  a  hypo- 
chlorite, but  as  a  compound  resulting  from  the  direct  combination  of  chlorine  with 
CaO(CaO,Cl ;)  iu  which  view  of  the  case  the  decomposition  is  explained  as  follows  : — • 

CaO,Cl-j-CO-=CaO,CO--l-Cl. 

The  value  of  the  decolorizing  chlorides  in  general,  and  of  chloride  of  lime  in  particular,  de- 
pends upon  the  quantity  of  chlorine  which  may  be  liberated  from  it  tmder  the  influence  of 
an  acid.  For  technical  purposes  this  estimation  is  exceedingly  important,  and  should  never 
be  neglected  by  the  bleacher. 

Chlorine,  whether  in  the  free  state,  or  combined  with  weak  alkalies,  or  caustic  lime, 
having  the  property  of  destroying  coloring  matter  of  an  organic  nature,  this  reaction  was 
from  the  firet  resorted  to  as  a  means  of  determining  the  commercial  value  of  these  chlo- 
rides ;  namely,  by  ascertaining  the  quantity  of  a  solution  of  indigo  of  known  strength  which 
could  be  decolorized  by  them  ;  for  this  purpose  a  test  liquor  is  prepared  by  dissolving  a 
given  quantity  of  sulphate  of  indigo  in  water,  and  pouring  therein,  drop  by  drop,  a  certain 
quantity  of  the  sample  of  chloride  of  lime  previously  dissolved  in  a  measured  quantity  of 
water.  The  solution  of  chloride  of  lime  must  be  added,  drop  by  drop,  to  the  sulphate  of 
indigo  test  liquor  until  the  latter  turns  from  blue  to  yellow,  the  operator  taking  care  to  stir 
the  mixture  without  intermission. 

This  method  of  chlorometry,  however,  is  objectionable,  and  is,  in  fact,  the  worst  of  all, 
on  account  of  the  difficulty  of  ascertaining  when  the  reaction  is  complete ;  for  the  yellow 
color,  resulting  from  the  decomposition  ot  the  indigo,  (chlorisatine,)  mixing  with  the  original 
blue  color  of  the  solution,  produces  a  green  color,  which  interferes  with  the  correctness  of 
the  observation.  On  the  other  hand,  the  test  liquor  of  sulphate  of  indigo  always  undergoes 
spontaneous  and  gradual  decolorization  by  standing,  not  only  when  exposed  to  diffused 
light,  but  even  though  it  be  kept  in  well  stoppered  bottles,  and  in  the  dark. 

The  process  generally  adopted  now  is  one  which  gives  exceedingly  accurate  results ;  it 
was  contrived  by  Gay-Lussac,  and  it  is  based  on  the  property  which  arsenious  acid  (AsO') 
in  solution  in  chlorhydric  acid  possesses  of  becoming  pcroxidizcd,  that  is  to  say,  converted 
into  arsenic  acid  (AsO^),  in  tlie  presence  of  chlorine  and  water.  This  reaction  may  be 
represented  by  the  following  equation : — 

AsO=  +  2C1  -f  2nO  = 
AsO*  -f-  2HC1. 

Tliat  is  to  say,  one  equivalent  of  arsenious  acid  (AsO')  in  presence  of  two  equivalents  of 
chlorine  (2C1)  and  of  two  equivalents  of  water  (2H0),  produces  one  equivalent  of  arsenic 
acid  (AsO')  and  two  equivalents  of  chlorhydric  acid  (2HC1.) 

This  reaction  is  so  rapid,  that,  if  organic  substances  capable  of  being  decolorized  by 
the  action  of  chlorine  are  present  while  it  is  taking  place,  the  color  is  not  destroyed  so  long 
as  any  portion  of  arsenious  acid  remains  unconverted  into  arsenic  acid  ;  but  as  soon  as  the 
last  portion  of  the  arsenious  acid  has  been  pcroxidizcd,  the  liquid  is  instantly  decolorized, 
which  reaction  at  once  indicates  that  the  experiment  is  at  an  end. 

Taking  the  equivalent  of  arsenious  acid  =  99,  and  that  of  chlorine  =  35-5,  it  is  evident 
that  99  grains  of  arsei)ious  acid  will  correspond  to  Vl'O  of  chlorine  (35-5  x  2  =r  71* ;)  or, 
which  is  the  same  thing,  139-436  grains  of  arsenious  acid  will  correspond  very  nearly  to  100 
of  chlorine. 

Take,  therefore,  a  certain  quantity  of  the  arsenious  acid  of  commerce,  reduce  it  to  pow- 
der, and  dissolve  it  in  hot  diluted  chlorhydric  acid  ;  allow  it  to  recrystallize  therefrom,  wash 
the  crystalline  powder  with  cold  water,  dry  it  well,  reduce  it  into  fine  powder,  and  of  this 
dry  and  pure  arsenious  acid  take  now  139  44  grains,  prepared  as  above  said,  put  them  into 
a  flask,  and  add  thereto  about  3  ounces  of  pure  chlorhydric  acid,/>vc  from  Rvlplmroux  and 
nitric  acid,  and  diluted  with  three  or  four  times  its  bulk  of  water ;  keep  the  whole  at  a 
boiling  heat  until  all  the  arsenious  acid  has  totally  dissolved.  Tour  now  the  solution  into  a 
glass  cylinder  graduated  into  10,000  grains-measures,  rinse  the  flask  with  water,  and  pour 
the  rinsings  into  the  graduated  glass  cylinder  until,  in  fact,  it  is  filled  up  to  the  scratch 
marked  10,000.  This  done,  it  is  clear  that  each  1,000  grains-measure  of  that  liquor  will 
contain  13-944  grains  weight  of  arsenious  acid,  corresponding  to  10  grains  weight  of  chlo- 
rine.    This  should  be  labelled  "  arsenious  acid  test  liquor."     If  it  be  desired  to  prepare  a 


CHLOROMETRY. 


82 'J 


larger  quantity  of  test  liquor,  instead  of  139"44,  the  operator  may  take,  for  example,  ten 
times  that  quantity  of  arsenious  acid,  namely,  1394  41  grains,  (or,  more  correctly,  1394-36,) 
and  dissolve  them  in  as  much  liquid  as  will  form  10i),000  grains-measures ;  but  he  will  have 
to  take  care  to  keep  it  in  one  or  more  well  stoppered  jars,  in  order  that  the  strength  of  the 
solution  may  not  be  altered  by  evaporation. 

Having  thus  prepared  a  quantity  of  arsenious  acid  test  liquor,  weigh  off  100  grains  from 
a  fair  average  sample  of  the  chloride  of  lime  to  be  examined,  and  after  triturating  them  first 
in  the  dry  state,  and  then  with  a  little  water  in  a  glass  mortar,  and  then  adding  more  water, 
pour  the  whole  into  a  flask  or  glass  vessel  capable  of  holding  2,000  grains-measure,  and 
marked  with  a  scratch  at  that  point.  The  mortar  in  which  the  chloride  of  lime  has  been 
triturated  must  be  rinsed  with  more  water,  and  the  rinsings  poured  into  the  2,000  grains- 
measure  glass  vessel  first  mentioned,  until  the  whole  of  the  2,000  grains-measures  are  filled 
up  to  the  scratch.  The  whole  must  now  be  well  shaken,  in  order  to  obtain  a  uniformly 
turbid  solution,  and  half  of  it  (namely,  1,000  grains-measure)  is  transferred  to  an  alka- 
limeter,  which  therefore  will  thus  be  filled  up  to  0\  and  will  contain  fifty  grains  of  the  chlo- 
ride of  lime  under  examination  ;  and  as  the  l,00i)  grains- measure  of  the  alkalimcter  are 
divided  into  100  degrees,  each  degree  or  division  will  therefore  contain  0'5,  or  half  a  grain 
of  chloride  of  lime. 

On  the  other  hand,  pour  also  1,000  grains-measure  of  the  arsenious  acid  test  liquor  into 
a  somewhat  large  beaker,  and  add  thereto  a  few  drops  of  a  solution  of  sulphate  of  indigo, 
in  order  to  impart  a  distinct  blue  color  to  it;  shake  the  glass,  so  as  to  give  a  circular  motion 
to  the  liquid,  and  while  it  is  whirling  round,  pour  gradually  into  it  the  chloride  of  lime 
liquor  from  the  alkalimeter,  watching  attentively  the  moment  when  the  blue  tinge  of  the 
arsenious  acid  test  liquor  is  destroyed.  Care  must  be  taken  to  stir  the  liquor  well  during 
the  process,  and  to  stop  as  soon  as  the  decolorizing  is  effected,  which  indicates  that  the 
whole  of  the  arsenious  acid  is  converted  into  arsenic  acid,  and  that  the  process  is  finished. 

The  quantity  of  chlorine  contained  in  the  sample  is  then  determined  in  the  following 
maimer : — 

We  have  seen  that  the  1,000  grains-measure  of  the  arsenious  acid  test  liquor,  into  which 
the  chloride  of  lime  liquor  was  poured  from  the  alkalimeter,  contained  13"944  grains  weight 
of  arsenious  acid,  corresponding  to  10  grains  weight  of  chlorine.  And  the  1,000  grains- 
measure  of  chloride  of  lime  liquor  poured  from  the  alkalimeter  contained  50  grains  weight 
of  chloride  of  lime,  each  degree  of  the  alkalimeter  containing,  therefore,  half  a  grain  of 
chloride  of  lime. 

Let  us  suppose  that,  in  order  to  destroy  the  blue  color  of  the  1,000  grains-measure  of  the 
arsenious  acid  test  liquor,  80  divisions  (800  grains-measure)  of  the  chloride  of  lime  liquor  in 
the  alkalimeter  have  been  employed.  It  is  evident  that  these  80  divisions  contained  the  10 
grains  weight  of  chlorine  necessary  to  destroy  the  color  of  the  arsenious  acid  test  solution, 
or  rather  to  peroxidize  all  the  arsenious  acid  (13-9 44)  contained  in  that  solution  tinged  blue 
with  indigo.  And  since  each  division  represents  half  a  grain  of  chloride  of  lime,  40  grains 
weight  of  chloride  of  lime,  containing  10  grains  weight  of  chlorine,  must  have  been  present 
in  the  80  divisions  employed.  If,  now,  40  grains  of  the  chloride  of  lime  under  examination 
contained  10  grains  of  chlorine,  what  is  the  percentage  of  chlorine  in  that  same  chloride? 
The  answer  is  25. 

40   :   10  ::  100  :   25. 

The  chloride  of  lime  submitted  to  the  experiment  contained,  therefore,  25  per  cent,  of 
chlorine. 

In  the  method  just  described  it  will  be  observed  that,  instead  of  pouring  the  arsenious 
acid  test  li(iuor  into  the  solution  of  the  sample,  as  in  alkalimetry,  it  is,  on  the  contrary,  the 
solution  of  the  sample  which  is  poured  into  that  of  the  test  liquor.  It  is  necessary  to  ope- 
rate in  this  manner,  because  otherwise,  the  chlorhydric  acid  of  the  arsenious  acid  test  liquor 
would  disengage  at  once  more  chlorine  than  the  arsenious  acid  could  absorb,  and  thus  ren- 
der the  result  quite  incorrect.  On  the  contrary,  by  pouring  the  chloride  of  lime  into  the 
solution  of  arsenious  acid,  the  chlorine  being  disengaged  in  small  portions  at  a  time,  alwa_ys 
meets  with  an  abundance  of  arsenious  acid  to  react  upon.  It  is  better,  also,  to  employ  the 
turbid  mixture  of  chloride  of  lime,  than  to  allow  it  to  settle  and  to  perform  the  experiment 
on  the  decanted  portion. 

Instead  of  arsenious  acid,  protosulphatc  of  iron  may  very  conveniently  bo  employed ; 
and  this  method,  first  proposed,  I  believe,  by  Runge,  yields  also  exceedingly  accurate  re- 
sults. 

This  method  is  based  upon  the  rapid  peroxidization  which  protosulphatc  of  iron  under- 
goes when  in  contact  with  chlorine  in  the  presence  of  water  and  of  free  suphuric  acid,  two 
equivalents  of  the  protosul[)hato  being  thereby  converted  into  one  equivalent  of  persul- 
phate, on  account  of  one  e<iuivalent  of  chlorine  liberating  one  equivalent  of  oxygen  from 
the  water,  which  equivalent  of  oxygen  adds  itself  to  the  protoxide  of  iron  which  thus  be- 
comes converted  into  peroxide,  and  consequently  into  persulphate  of  iron,  while  the  cquiva- 


330  CHLOROMETEY. 

lent  of  hydrogen,  liberated  at  the  same  time,  forms  with  the  chlorine  one  equivalent  of 
chlorhydric  acid :  thus : — 

2FeO,SO''  +  2S0^  -f-  HO  -j-  CI  = 

Fe-0\3S0'  -]-  IlCl ; 

bv  wliicli  it  is  seen  that  two  equivalents  of  protosulphate  of  iron  correspond  to  one  cquiv;, 
lent  of  chlorine. 

Protosulphate  of  iron  may  be  obtained  in  a  state  of  great  purity  as  a  by-product  of  the 
action  of  sulphuric  acid  upon  protosulphuret  of  iron  in  the  preparation  of  sulphuretted  hy- 
drogen, the  evolution  and  reducing  action  of  the  latter  gas  preventing  the  formation  of  any 
peroxide.  All  the  operator  has  to  do  is  to  redissolve  in  water,  with  addition  of  a  little  sul- 
phuric acid,  the  crystals  which  have  formed  in  the  sulphuretted  hj^rogen  apparatus,  to  fil- 
ter the  whole  lifpior  and  to  recrystallize  it ;  or  else  to  pour  the  hot  and  very  concentrated 
solution  into  strong  alcohol :  by  the  latter  process,  instead  of  obtaining  the  protosulphate  in 
crystahs,  it  is  in  the  shape  of  a  fine  clear  blue  precipitate.  Or  else,  as  much  piano-forte 
wire  may  be  dissolved  in  moderately  diluted  sulphuric  acid  as  will  nearly  neutralize  it ;  the 
liquor  is  then  filtered  and  left  to  crystallize,  taking  care,  however,  to  leave  a  few  fragments 
of  the  wire  suspended  in  it,  that  no  pcroxidization  may  take  place ;  or  else  the  iron  solution 
may  be  concentrated  by  heat,  and  while  hot  pour  into  strong  alcohol,  by  which  a  clear  blue 
crystalline  precipitate  of  pure  protosulphate  of  iron  will  be  obtained.  In  either  case  the 
protosulphate  of  iron  so  produced  contains  7  equivalents  of  water,  of  crystallization 
(FeO,S0^7HO.) 

Take,  accordingly,  2  equivalents,  or  278  grains,  of  the  crystallized  protosulphate  of  iron, 
before  alluded  to,  and  previously  dried  between  folds  of  blotting-paper,  or  moistened  with 
alcohol,  and  left  to  dry  in  the  air  until  all  odor  of  alcohol  has  vanished,  and  dissolve  these 
278  grains  of  protosulphate  of  iron  in  water  strongly  acidified  with  either  sulphuric  or  chlor- 
hydric acid,  so  that  the  liquor  may  occupy  the  bulk  or  volume  of  3,550  grains  of  water. 
IJOOO  grains  of  such  a  solution  will  therefore  contain  78'31  grains  of  crystallized  protosul- 
phate of  iron,  and  will  accordingly  be  peroxidized  by,  or  will  correspond  to,  10  grains  of 
chlorine.  When  only  one  experiment  is  contemplated,  78'31  of  crystallized  protosulphate 
of  iron  may  be  at  once  dissolved  in  1,000  grains  (1  alkalimeter  full)  of  water  acidified  with 
sulphuric  acid  ;  and  this  is  the  protosulphate  of  iron  test  liquor. 

Wei"'h  now  100  grains  of  the  chloride  of  lime  under  examination,  and  dissolve  them,  as 
before  mentioned,  in  a  glass  mortar,  with  a  sufficient  quantity  of  water,  so  that  it  may  oc- 
cupy the  bulk  of  2,000  grains-measures  of  water ;  pour  half  of  this,  namely,  1,000  grains- 
measure,  into  an  alkalimeter,  divided,  as  usual,  into  100  divisions  or  degrees,  each  degree 
of  which  will  therefore  contain  half  a  grain  of  chloride  of  lime.  Pour  gradually  the  chlo- 
ride of  lime  from  the  alkalimeter  into  a  glass  beaker  containing  1,000  grains-measure  of  the 
test  solution  of  protosulphate  of  iron,  above  alluded  to,  stirring  all  the  while,  until  it  is 
completely  converted  into  persulphate  of  iron,  which  may  be  ascertained  by  means  of  strips 
of  paper,  previously  dipped  into  a  solution  of  red  prussiate  of  potash,  and  dried,  more  chlo- 
ride of  lime  being  poured  from  the  alkalimeter  as  long  as  a  blue  stain  is  produced  by  touch- 
ing the  red  prussiate  of  potash  test  paper  with  a  drop  of  the  solution  of  protosulphate  of 
iron  operated  upon.  The  quantity  of  chlorine  contained  in  the  chloride  of  lime  under 
examination,  is  estimated  as  follows: — Since  1,000  grains-measure  of  the  protosulphate  of 
iron  test  litpior,  into  which  the  solution  of  chloride  of  lime  is  poured,  contains,  as  we  said, 
78'31  grains  of  protosulphate  of  iron,  corresponding  to  10  grains  of  chlorine  ;  and  since,  on 
the  other  hand,  1,000  grains-measure  of  the  solution  of  chloride  of  lime  in  the  alkalimeter 
contains  50  grains  of  chloride  of  lime,  tliat  is  to  say,  i  grain  of  that  substance  in  each  divi- 
sion of  the  alkalimeter : 

Let  us  suppose,  for  example,  that  the  quantity  of  chloride  of  lime  required  to  peroxidize 
the  iron  of  the  1,000  grains-measure  of  protosulphate  amounts  to  90  divisions,  it  is  evident 
that  the  solution  contained  45  grains  of  chloride  of  lime,  and  if  these  45  grains  of  chloride 
of  lime  contained  the  10  grains  of  chlorine  necessary  to  peroxidize  the  iron  of  the  protosul- 
phate in  the  glass  beaker,  the  100  grains  of  the  same  chloride  under  examination  evidently 
contain  22-22.  Tiiis  calculation  is  readily  effected  by  dividing  1,000  by  half  the  number  of 
the  divisions  poured  from  the  alkalimeter.  The  half  of  90  (number  of  divisions  employed) 
being  45,  dividing  1,000  by  45  is  22-22. 

Or,  instead  of  100  grains,  the  operator  may  take  only  50  grains  of  the  chloride  of  lime 
to  be  examined,  and  this  will  prove  a  more  convenient  quantity,  in  that  case,  the  dividing 
1,000  by  the  innnbcr  of  divisicms  employed,  will  at  once  give  the  percentage.  Let  us  sup- 
pose, for  example,  that  45  divisions  only  of  the  50  grains  of  chloride  of  lime  solution,  taken 
as  sample,  to  have  been  employed  ;  then,  since  these  45  divisions  contained  the  10  grains 
of  chlorine  necessary  to  peroxidize  the  iron  contained  in  the  1,000  grains-measure  of  the 
protosulphate,  it  is  evident  that  IdO  grains  will  contain  22-22  of  chlorine,  thus: — 

Divisions.         Grains  of  Chlorine.         Divisions.         Grains  of  Chlorine. 
45  :  10  : :  100  :  x  =  22-22 


CHLOKOMETRY.  331 

Tliere  are  other  accurate  methods  of  determining  the  amomit  of  chlorine  in  chloride  of 
liuie,  provided  a  proper  care  be  bestowed  on  tlie  operation  ;  but  the  processes  by  arsenious 
acid  and  by  proto-sulphate  of  iron  are  by  far  the  less  liable  to  error  from  the  circumstance, 
among  other  reasons,  that  their  solutions  are  less  liable  to  become  altered.  The  other 
methods  also  require  a  longer  time,  and  we  shall  only  mention  the  rationale  of  their  mode 
of  action. 

Thus  the  process  by  chloride  of  manganese  consists  in  decomposing  a  test  solution  of  it 
by  the  chloride  of  lime,  to  be  examined  as  long  as  a  brown  precipitate  is  produced.  The 
reaction  is  as  follows  : — 

MnCl  -I-  CaO,Cl  +  H0= 
MnO-  -f-  CaCl  +  HCl. 

The  process  with  yellow  j)russiate  of  potash  depends  upon  the  following  reaction  : — 

2(FeCy  -f  2KCy)  -f  CI  = 
(3KCy  +  Fe'^Cy^)  -f  KCl. 

That  is  to  say,  2  equivalents  of  yellow  prussiate  (ferrocyanide  of  potassium)  produce  1 
equivalent  of  red  prussiate,  (ferricyanide  of  potassium,)  1  equivalent  of  chloride  of  potas- 
sium ;  and,  therefore,  2  equivalents  =  422  grains  of  the  yellow  prussiate  will  correspond 
to  1  equivalent  =  35'5  of  chlorine.  The  chloride  of  lime  is,  as  usual,  poured  into  the  solu- 
tion of  the  chloride  of  manganese,  and  the  operation  is  completed  when  a  brown  color 
begins  to  appear. 

The  process  by  suhchloride  of  mercury,  (Hg^Cl,)  which  is  insoluble  in  water,  is  based 
upon  its  conversion  by  chlorine  into  chloride  of  mercury,  (HgCl,)  which  is  soluble  in  water, 
thus  :— 

Hg^Cl  -f-  Cl  = 
2HgCI. 

The  modus  operandi  is  briefly  as  follows : — As  subnitrate  of  mercury  is  difficult  to 
obtain  in  a  perfectly  neutral  state,  and  free  from  basic,  or  from  pernitrate,  take  a  known 
volume  of  pernitrate  of  mercury,  precipitate  it  by  an  addition  of  chlorhydric  acid,  collect  the 
precipitate  formed,  wash  it,  dry  it  at  212"  F.,  and  weigh  it.  Having  thus  ascertained  the 
quantity  of  subchloride  of  mercury  contained  in  the  known  bulk  of  pernitrate,  1,000  grains- 
measure  of  it  are  measured  off,  and  precipitated  by  an  excess  of  chlorhydric  acid,  and  the 
whole  is  then  well  shaken,  so  as  to  agglomerate  it ;  a  given  weight  of  chloride  of  lime,  say 
50  grains,  are  dissolved,  as  usual,  in  water,  so  as  to  obtain  one  alkalimeter  full,  which  is 
then  gradually  poured  into  the  liquor  containing  the  precipitated  subchloride  of  mercury, 
until  it  completely  disappears,  and  the  liquor  becomes  as  clear  as  water,  which  indicates  that 
the  operation  is  at  an  end.  The  number  of  divisions  of  the  chloride  of  lime  liquor  used  are 
then  read  off,  and  the  quantity  of  chlorine  present  in  the  chloride  of  lime  is  easily  calculated 
from  the  quantity  of  subchloride  of  mercury  which  was  known  to  have  existed  in  the  known 
bulk  of  pernitrate  employed,  and  which  has  been  converted  into  perchloride  of  mercury  by 
the  chlorinated  liquor  poured  into  it. 

Testing  of  Black  Oxide  of  Manganese  for  its  available  Oxygen. 

Manganese  is  found,  in  combination  with  more  or  less  oxygen,  in  a  number  of  minerals, 
but  the  principal  ores  of  that  substance  are  the  pyrolusite,  (binoxide  of  manganese,)  MnO'^ 
braunite,  (sesquioxide  of  manganese,)  Mn'^O^,  manganite,  (hydrated  sesquioxide  of  man- 
ganese,) Mn-O^-1-HO,  hausmannite,  (red  oxide  of  manganese,)  MnW,  &c.,  &c. 

The  first,  namely  the  pyrolusite,  is  by  far  the  most  important  of  these  ores,  which  are 
chiefly  employed  for  the  preparations  of  chlorine,  and  their  commercial  value  depends  upon 
the  quantity  of  this  gas  which  a  given  weight  of  them  can  evolve,  which  quantity  is  propor- 
tionate to  that  of  the  oxygen  contained  in  the  ore  beyond  that  which  constitutes  tlie 
protoxide  of  that  metal,  as  will  be  shown  presently.  The  manufacturer  who  uses  these  ores, 
ought  also  to  take  into  consideration  the  amount  of  impurities  wliich  may  be  present  in 
tWem,  such  as  earthy  carbonates,  peroxide  of  iron,  alumina,  silica,  sulphate  of  barytes,  since 
these  impurities  diminish,  pro  tanto,  the  value  of  the  ore.  The  estimation  of  the  conmicr- 
cial  value  of  a  manganese  ore  may  be  accomi)lished  in  various  ways. 

One  of  these  methods  consists  in  first  reducing  into  fine  powder  a  sample  of  the  ore,  and 
treating  it  by  moderately  diluted  nitric  acid.  If  this  ])roducos  an  effervescence,  it  is  owing 
to  the  presence  of  carbonates,  and  an  excess  of  niti-ic  acid  should  then  be  used,  so  as  to  dis- 
solve tliem  entirely.  When  all  effervescence  has  ceased,  even  after  a  fresh  addition  of 
acid,  the  whole  should  Ije  thrown  on  a  filter  and  the  residue  within  the  filter  should  bo 
washed  and  dried.  For  technical  purposes,  the  weight  of  tliesc  carbonates  may  be  thus 
easily  effected,  namely,  by  weighing  a  certain  quantity  of  the  sample,  (for  example  H>0 
grains,)  digesting  it  for  a  few  hours  in  dilute  nitric  acid,  collecting  on  a  filter,  washing,  and 
drying  until  it  no  longer  diminishes  in  weight.  The  loss  indicates,  of  coui-se,  the  quantity 
per  cent,  of  the  carbonates  which  it  contained.     This  being  done,  take  a  weighed  quantity 


332  CHLOROMETRY. 

of  the  sample,  dry  it  well,  as  just  said,  introduce  it  into  a  small  counterpoised  retort,  at  the 
extremity  of  which  a  tube  containing  fragments  of  fused  chloride  of  calcium,  also  weighed, 
should  be  adjusted.  Apply  then  to  the  retort  the  strongest  heat  that  can  be  produced  by  an 
argand  spirit  lamp,  or  by  my  gas  furnace-lamp,  and,  after  some  time,  disconnect  the  chlo- 
ride of  calcium  tube  and  weigh  it.  The  increase  of  weight  indicates  the  quantity  of  water 
which  has  volatilized,  and  which  was  yielded  principally  by  the  hydrate  of  sesquioxide, 
(manganite,  Mn"0^+HO,)  some  portion  of  which  is  always  found  mixed  with  the  peroxide; 
every  grain  of  water  thus  evaporated  corresponds  to  9-77  of  manganite. 

The  contents  of  the  small  retort  should  now  be  emptied  into  a  counterpoised  platinum 
capsule  or  crucible,  and  ignited  therein,  until,  after  repeated  weighings,  the  weight  is  ob- 
served to  remain  uniform  ;  this  converts  the  mass  completely  into  nianganoso-manganic 
oxide  (Mn'O').  The  crucible  is  then  weighed,  and  the  loss  indicates  the  quantities  of  oxy- 
gen evolved,  from  which  that  of  the  peroxide  is  calculated.  Each  grain  of  oxygen  corre- 
sponds to  2-71  of  pure  peroxide.  This  experiment  should  evidently  be  carried  on  with  great 
care,  since  a  small  quantity  of  oxygen  represents  a  large  quantity  of  {leroxidc. 

In  order  to  eft'ect  the  complete  conversion  of  the  peroxide  in  the  sample  into  red  oxide 
of  manganese,  as  above  mentioned,  the  ignition  should  be  continued  lor  a  long  time,  and 
the  quantity  operated  upon  should  be  small ;  if  a  larger  tjuantity  be  treated,  a  common  fire 
should  be  used  instead  of  an  argand  lamp. 

The  value  of  manganese  may  also  be  very  accurately  estimated  by  measuring  the  quan- 
tity of  chlorine  which  a  given  weight  of  the  ore  produces,  when  treated  by  chlorhydric 
acid. . 

In  order  to  understand  the  rationale  of  this  method,  the  reader  must  bear  in  mind  that 
all  the  oxides  of  manganese,  when  heated  in  contact  with  chlorhydric  acid,  evolve  a  quantity 
of  chlorine  exactly  proportionate  to  that  of  the  oxygen  above  that  which  it  contained  in  the 
protoxide.  For  example,  protoxide  of  manganese  being  treated  Ijy  chlorhydric  acid,  pro- 
duces only  protochloride  of  manganese,  but  yields  no  free  chlorine,  as  shown  by  the  follow- 
ing equation  :  MnO  +  HC)=MnCl-|-HO.  Kot  so,  however,  the  red  oxide  of  manganese,  or 
manganoso-manganic  oxide  (Mn^O"),  which,  when  treated  by  chlorhydric  acid,  forms  proto- 
chloride of  manganese,  but  disengages  one  third  of  an  equivalent  of  chlorine,  as  shown  by 
the  following  equation :  Red  oxide  of  manganese,  or  manganoso-manganic  oxide,  may  be 
represented  by  the  formula  MnO-l-Mn''0^  or  by  Mn^O^,  or  by  SMuOl^  ;  therefore  :   l^MnO 

-h  1  JHC1=  1  jilO -u  MnCl -1- iCl- 

Sesquioxide  of  manganese,  when  treated  by  chlorhydric  acid,  yields  half  an  equivalent 
of  free  chlorine  for  each  equivalent  of  protochloride  of  manganese  formed  ;  as  shown  by  the 
following  equation  :  Sesquioxide  of  manganese,  Mn'^O^,  is  the  same  as  2ilu01^  ;  therefore 
UMnO  +  UHC1  =  HH0  +  MnCl -f -iCl. 

Lastly,  peroxide  of  manganese,  when  treated  by  chlorhydric  acid,  yields  one  entire 
equivalent  of  chlorine  for  each  equivalent  of  protochloride  formed,  as  shown  by  the  follow- 
ing equation  :  Peroxide  of  manganese  is  MnO" ;  therefore  MnC  +  2HC1=  2II0  -I-  MnCl  +  CI. 
And  as  the  commercial  value  of  the  ores  of  manganese  depends,  as  already  said,  upon  the 
amount  of  chlorine  which  they  can  evolve  when  treated  by  chlorhydric  acid,  the  object  in 
view  will  evidently  be  attained  by  determining  that  quantity. 

Runge's  method,  which  we  detailed  at  the  beginning  of  this  article  in  the  testing  of 
chloride  of  lime,  may  also  be  applied  for  the  testing  of  the  ores  of  manganese.  That 
method,  it  will  be  recollected,  is  based  upon  the  rapid  peroxidization  which  sulphate  of 
protoxide  of  iron  undergoes  when  in  contact  with  chlorine,  water  being  present,  which  reac- 
tion is  represented  as  follows:  2FeO,SO^-f  IIO-l- Cl  =  FeW,SO'+ HCl.  Showing  that  two 
equivalents  of  protosulphate  of  iron  represent  one  equivalent  of  chlorine,  since  one  equiva- 
lent of  chlorine  is  required  to  convert  two  equivalents  of  protosulphate  of  iron  into  one  of 
the  persulphate  of  that  base.  The  experiment  is  performed  as  follows :  Pulverize  278 
grains  (2  e(iuivalcnts)  of  crystallized  protosulphate  of  iron,  (2FeO,S()^,7HO,)  and  mix  them 
ill  a  small  llask  with  43 '6  grains  of  the  manganese  under  examination,  and  previously  re- 
duced into  very  fine  powder.  These  43'6  grains  represent  one  equivalent  of  i)ure  binoxide 
of  manganese,  (MnO",)  and  would,  therefore,  if  pure,  peroxidize  exactly  the  two  e(|uivalentp, 
or  278  of  protosulphate  of  iron.  About  three  fluid  ounces  of  strong  chlorhydric  acid  should 
now  be  poured  upon  the  mixture  in  the  flask,  which  flask  must  be  inmiediately  closed  with 
a  perforated  cork,  provided  with  a  tube-funnel  drawn  to  a  point,  in  order  that  the  vapor 
may  escape,  and  the  whole  is  then  rapidly  boiled.  The  chlorine  disengaged  by  the  man- 
ganese is  immediately  absorbed  by  the  protosulphate  of  iron.  We  just  said  that  4o'6  grains 
erf  peroxide  of  manganese  would,  if  pure,  exactly  peroxidize  the  278  grains  of  protosulphate 
of  iron,  but  as  the  peroxide  of  manganese  of  commerce  is  never  pure,  it  is  evident  that  the 
43 '6  grains  of  the  sample  employed  will  prove  insuflicient  to  peroxidize  the  iron,  and  hence, 
the  necessity  of  ascertaining  the  amount  of  protosulphate  which  could  not  be  peroxidized, 
and  which  remains  in  the  acid  solution.  This  may  be  done  by  means  of  a  chlorate  of  potash 
test-lifiuor,  as  follows  :  Since  1  equivalent  (  =  122'.5  grains)  of  chlorate  of  potash  (=rKf),C10^) 
produce,  under  the  influence  of  boiling  chlorhydric  acid,   6  equivalents  of  chlorine,   as 


CHLOROMETEY.  333 

shown  by  the  equation  :  KO.CIOH  6IIC1  =  KC1  +  6H0  +  6C1,  it  follows  that  20-41  of  chlorate 
of  potash  would  be  sufficient  to  peroxidize  278  grains  (2  equivalents)  of  protosulphate  of 
iron,  and  would  therefore  represent  35'5  (1  equivalent)  of  chlorine,  or  Ali'Q  of  peroxide  of 
manganese. 

The  chlorate  of  potash  test  liquor,  therefore,  is  prepared  by  dissolving  20'41  of  chlorate 
of  potash  in  1,000  water-grains'  measure  of  water.  The  solution  is  then  poured  careluUy, 
drop  by  drop,  from  a  glass  alkalimeter  through  the  tube  funnel  into  the  boiling  hot  solution 
containin<^  the  salt  of  iron.  The  whole  of  the  chlorine  which  is  disengaged  is  immediately 
absorbed  by  the  protosulphate  of  iron,  but  as  soon  as  the  latter  is  completely  peroxidized, 
the  free  chlorine  which  is  evolved  immediately  reacts  upon  the  coloring  matter  of  a  slip  of 
paper,  stained  blue  by  sulphate  of  indigo,  or  litmus,  previously  placed  by  the  operator  be- 
tween the  cork  and  the  neck  of  the  flask,  which  piece  of  paper  becoming  bleached  indicates 
that  tlie  operation  is  terminated.  The  operator  then  reads  off  the  number  of  measures  of 
the  chlorate  of  potash  test  liquor  which  have  been  employed  to  complete  the  peroxidization 
of  the  protosulphate  of  iron. 

Let  us  suppose  that  50  divisions  of  the  alkalimeter  (500  water-grains'  measures)  have 
been  employed  ;  it  is  clear  that  half  the  quantity  only  of  the  protosulphate  of  iron  employed 
has  been  converted  into  persulphate,  and  that  consequently  the  quantity  of  the  sample  of 
manganese  contained  half  its  weight  of  valueless  material ;  -or,  in  other  words,  each  measure 
of  the  test  solution  of  chlorate  of  potash  employed  to  complete  the  peroxidization  of  the 
protosulphate  represents  1  per  cent,  or  2r8  grains  of  useless  matter  contained  in  the  43-6 
grains  of  the  ore  of  manganese  operated  upon.  The  air  should  be  excluded  from  the  flask 
(luring  the  peroxidization  of  the  protosulphate  of  iron,  else  the  oxygen  of  the  air  acting  upon 
the  salt  of  iron,  would  peroxidize  a  portion  of  it  and  vitiate  the  result.  Instead  of  protosul- 
l)liate,  protochloride  of  iron  may  be  used,  for  which  purpose  56  grains  (2  equivalents)  of 
piano-forte  wire  should  be  put  into  a  matras  or  flask  as  above  mentioned,  and  about  four 
fluid  ounces  of  pure  concentrated  chlorhydric  acid  poured  upon  them.  The  flask  being 
closed,  as  directed  in  the  preceding  process,  with  a  cork  provided  with  a  funnel  tube  drawn 
to  a  point  at  the  lower  end,  a  gentle  heat  is  then  applied  to  promote  the  solution  of  the  iron. 
When  all  the  metal  has  dissolved,  the  operator  introduces  43'6-  grains  of  the  peroxide  of 
manganese  under  examination,  previously  reduced  into  fine  powder  and  kept  in  readiness, 
weighed  and  folded  up  in  a  piece  of  paper ;  the  flask  is  immediately  closed  with  its  cork, 
the  liquor  is  slightly  agitated  and  then  brought  to  the  boiling  point.  The  chlorine  disen- 
gaged by  the  manganese  is  completely  absorbed  by  the  protochloride  of  iron,  the  excess 
of  which  is  determined  by  the  chlorate  of  potash  test  liquor  precisely  as  explained  just 
above. 

By  the  methods  which  we  have  described  the  proportion  of  chlorine  which  a  sample  of 
manganese  can  evolve  may  be  ascertained,  but  this  alone  is  far  from  constituting  the  com- 
mercial value  of  the  article  as  a  source  of  chlorine,  and  it  is  not  less  important  to  determine 
the  proportions  of  the  other  substances,  such  as  peroxide  of  iron,  earthy  carbonates,  &c., 
which  are  contained  in  the  sample,  and  which  unprofital^ly  consume  a  certain  quantity  of 
hydrochloric  acid  without  evolving  chlorine,  and  merely  producing  chlorides  of  iron,  of  cal- 
cium, of  barium,  &c.  Hence  the  necessity  of  estimating  not  only  the  quantity  of  chlorine 
which  a  given  weight  of  peroxide  of  manganese  can  yield,  but  likewise  the  proportion  of  hy- 
drochloric acid  which  is  uselessly  saturated  by  the  foreign  substances  contained  in  the  ore. 
For  this  purpose  the  following  method,  which  was  first  recommended  by  Gay-Lussac,  may 
be  resorted  to : — One  equivalent,  or  43'6  grains,  of  the  peroxide  of  manganese  under 
examination  are  treated  by  an  excess  of  hydrochloric  acid ;  for  example,  by  500  water-grain 
measures  of  chlorhydric  acid  of  specific  gravity  1-093,  which  quantity  contains,  according  to 
Dr.  Ure,  100  grains  of  real  acid.  The  amount  of  chlorine  corresponding  to  that  of  the  pure 
manganese  in  the  sample  is  then  determined  as  mentioned  before  by  means  of  protosulphate 
or  protochloride  of  iron. 

Since  43-6  grains  (one  equivalent)  of  pure  peroxide  of  manganese  require  74  grains  (two 
equivalents)  of  pure  chlorhydric  acid  to  evolve  35-5  of  clilorine,  if  we  saturate  the  excess  of 
chlorhydric  acid  employed  by  means  of  a  solution  of  carbonate  of  soda,  as  in  acidimctry, 
and  thus  determine  the  quantity  of  free  acid,  the  difference  will  at  once  show  what  quantity 
of  acid  has  been  consumed  both  by  the  peroxide  of  manganese  and  by  the  foreign  sub- 
stances conjointly ;  but  if  we  now  subtract  from  that  number  the  quantity  consumed  by  tlie 
manganese,  which  will  have  been  ascertained  in  the  first  jtart  of  the  experiment,  the  re- 
mainder will,  of  course,  represent  the  proportion  which  has  been  uselessly  consumed  by  the 
impurities. 

Taking  a  test  solution  of  carbonate  of  soda  of  such  a  strength  that  100  alkalimetrical 
divisions  contain  exactly  53  grains  (one  equivalent)  of  it,  and  are  conscfiuently  capable  of 
saturating  exactly  3r)-5  grains  (one  equivalent)  of  pure  chloriiydric  acid,  let  us  suppose  that 
in  order  to  saturate  the  excess  of  free  acid  left  after  tlu.'  determination  of  the  chlorine 
evolved  by  the  manganese,  it  is  found  tliat  Mt)  alkalimetrical  divisions  of  the  test  solution 
of  carbonate  of  soda  just  alluded  to  have  been  required.     Since  100  alkalimetrical  divisions 


33i  CHLOROPHANE. 

or  measures  of  carbonate  of  soda  can  saturate  36-5  grains  of  pure  chlorhydric  acid,  tlie  140 
divisions  or  measures  employed  represent,  therefore,  51-1  grains  of  acid  left  in  excess  and 
in  a  free  state,  which  being  deducted  from  the  lUO  grains  (contained  in  the  500  grain 
measures  of  acid  of  specific  gravity  r093  employed)  leave  48-9  grains  as  the  proportion  of 
real  acid  consumed  by  the  manganese  and  impurities  of  the  sample.  Let  us  suppose,  now, 
that  the  43-6  grains  of  manganese  operated  upon  have  been  found  in  the  first  part  of  the 
experiment  to  contain  only  21 '8  grains,  or  50  per  cent,  of  peroxide  of  manganese  as  before 
mentioned;  these  will,  therefore,  have  consumed  3G'5  grains  of  chlorhydric  acid,  which 
being  deducted  from  the  489  grains,  (the  joint  quantity  of  acid  consumed  by  the  acid  and 
impurities,)  leave  12"4  as  the  proportion  of  pure  chlorhydric  acid  wasted  or  uselessly  taken 
up  by  the  impurities  alone,  and  therefore  the  43 '6  grains  of  peroxide  of  manganese  operated 
npon  consisted  of 

Pure  peroxide  of  manganese 21 'S     =     50*00 

Impurities  unprofitably  consuming  chlorhydric  acid       -     12"4     =     28*44 
Other  impurities    -         -         - 9-4     —     21  "56 


43-6     =  100-00 

The  amount  of  water  contained  in  the  sample  may  be  separately  estimated  by  exposing 
a  given  weight  of  it  (100  grains,  for  example,)  in  a  capsule,  at  a  temperature  of  about 
215'  Fahr.  until  they  no  longer  lose  weight.  The  loss,  of  course,  indicates  the  percentage 
of  water. 

The  economy  of  any  sample  of  manganese  in  reference  to  its  consumption  of  acid,  in 
generating  a  given  quantity  of  chlorine,  may  be  ascertained  by  the  oxalic  acid  test : — 44 
grains  of  the  pure  peroxide,  with  93  grains  of  neutral  oxalate  of  potash,  and  98  of  oil  of 
vitriol  disengage  44  grains  of  carbonic  acid,  and  afford  a  complete  neutral  solution ;  be- 
cause the  one  half  of  the  sulphuric  acid,  =  49  grains,  goes  to  form  an  atom  of  sulphate  of 
manganese,  and  the  other  half  to  form  an  atom  of  sulphate  of  potash. 

The  deficiency  in  the  weight  of  carbonic  acid  thrown  off  will  show  the  deficiency  of 
peroxide  of  manganese  ;  the  quantity  of  free  sulphuric  acid  may  be  measured  by  a  test 
solution  of  bicarbonate  of  potasli,  and  the  quantity  neutralized,  compared  to  the  carbonic  gas 
produced,  will  show  by  the  ratio  of  98  to  44,  the  amomit  of  acid  unprofitably  consumed. — 
A.  N. 

CHLOROPHANE.  A  name  given  to  some  of  the  varieties  of  fluor  spar.  See  pLroR 
Spar. 

CHROMATES  OF  POTASH.  (For  the  preparation  of  these  salts,  refer  to  Chrome 
Iron.)  Bichromate  of  potash,  by  slow  cooling,  may  be  obtained  in  the  form  of  square  ta- 
bles, with  bevelled  edges,  or  flat,  four-sided  prisms.  They  are  permanent  in  the  air,  have 
a  metallic  and  bitter  taste,  and  dissolve  in  about  one-tenth  of  their  weight  of  water  at  60' 
F.,  but  in  one  half  of  their  weight  of  boiling  water.  The  composition  of  bichromate  of 
potash  is 

Potash 31-6 

Chromic  acid --        68-4 

100-0 
That  of  the  neutral  Chromatc  of  Potash  is 

Potash 48-0 

Chromic  acid 520 

100-0 
These  salts  arc  much  employed  in  Calico  Printing  and  in  Dyeing,  which  see. 
The  value  of  a  solution  of  chromatc  of  potash,  if  it  be  tolerably  pure,  may  be  in- 
ferred from  its  specific  gravity  by  the  following  table  : — 

At  specific  gravity  1-28  it  contains  about  50  per  cent  of  the  salt. 
"  "  121  "  "       33  "  " 

"  "  1-18         "  "       25 

u  II  1.J5         u  a       20  "  " 

"  »  M2         "  "        16  "  *' 

II  ((  \-\0         "  "        12  "  " 

In  making  the  red  bichromate  of  potash  from  these  solutions  of  the  yellow  salt,  nitric 
acid  was  at  first  chiefly  used ;  but  in  consequence  of  its  relatively  high  price,  sulphuric, 
muriatic,  or  acetic  acid  has  been  frequently  substituted  upon  the  large  scale. 

CIIROMATE  OF  LEAD,  the  chrome  yellow  of  the  painter,  is  a  rich  pigment  of  various 
shades,  from  deep  orange  to  the  palest  canary  yellow.  It  is  made  by  adding  a  limpid  sohi- 
tion  of  the  neutral  chromatc  of  potash,  to  a  solution,  equally  limpid,  of  acetate  or  nitrate  of 
lead.    A  precipitate  falls  which  must  be  well  washed  and  carefully  dried  out  of  the  reach  of 


CHROME  IRON. 


335 


any  sulphuretted  vapors.  A  lighter  shade  of  yellow  is  obtained  by  mixing  some  solution 
of  alum  or  sulphuric  acid  with  the  chromate  before  pouring  it  into  the  solution  of  lead  ; 
and  an  orange  tint  is  to  be  procured  by  the  addition  of  subacetate  of  lead  in  any  desired 
proportions. 

It  was  ascertained  by  MM.  Riot  and  Delisse,  that  the  proportion  of  chromic  acid  in 
cliromate  of  lead  may  be  much  diminished  without  any  injury  to  the  color,  and  that  the 
same  color  is  produced  with  25  parts  of  neutral  chromate  for  100  of  chrome  yellow,  as  when 
5 1  parts  are  used.  They  give  the  following  formula  for  the  preparation  of  this  pigment. 
Acetate  of  lead  is  dissolved  in  water,  and  sulphuric  acid  in  quantity  necessary  to  convert 
the  oxide  of  lead  into  sulphate  is  added.  The  clear  liquid  contains  acetic  acid,  and  may  be 
drawn  off  and  preserved  for  the  preparation  of  fresh  acetate  of  lead.  The  sulphate  of  lead 
is  washed  and  treated  with  a  hot  solution  of  neutral  chromate  of  potash,  25  parts  being 
used  for  every  75  parts  of  sulphate  of  lead.  The  liquid  then  contains  sulphate  of  potash 
which  may  be  made  available,  and  the  precipitate  consists  of  chromate  of  sulphate  of  lead. 

To  prepare  chrome  red,  Runge  directs  an  intimate  mixture  to  be  made  of  448  lbs.  of 
litharge,  60  lbs.  of  common  salt,  and  5(X)  lbs.  of  water.  As  soon  as  the  mass  becomes  white 
and  swells  up  considerably,  more  water  is  added  to  prevent  it  from  becoming  too  hard. 
After  four  or  five  days,  the  mass  becomes  a  compound  of  chloride  and  hydrated  oxide  of 
lead.  Without  separating  the  mother  liquor,  which  contains  undeconiposed  chloride  of 
sodium  and  soda,  150  lbs.  of  })0wdered  bichromate  of  potash  are  to  be  added,  and  the  whole 
well  stirred  together,  and  finally  washed. 

Liebig  and  AViihler  have  lately  contrived  a  process  for  producing  a  subchromate  of  lead 
of  a  beautiful  vermilion  hue.  Into  saltpetre,  brought  to  fusion  in  a  crucible  at  a  gentle 
heat,  pure  chrome  yellow  is  to  be  thrown  by  small  portions  at  a  time.  A  strong  ebullition 
takes  place  at  each  addition,  and  the  mass  becomes  black,  and  continues  so  while  it  is  hot. 
The  chrome  yellow  is  to  be  added  till  little  of  the  saltpetre  remains  undecomposed,  care 
being  taken  not  to  overheat  the  crucible,  lest  the  color  of  the  mixture  should  become 
brown.  Having  allowed  it  to  settle  for  a  few  minutes,  during  which  the  dense  basic  salt 
falls  to  the  bottom,  the  fluid  part,  consisting  of  chromate  of  potash  and  saltpetre,  is  to  be 
poured  off,  and  it  can  be  employed  again  in  preparing  chrome  yellow.  The  mass  remaining 
in  the  crucible  is  to  be  washed  with  water,  and  the  chrome  red  being  separated  from  the 
other  matters,  it  is  to  be  dried  after  proper  edulcoration.  It  is  essential  for  the  beauty  of 
the  color,  that  the  saline  solution  should  not  stand  long  over  the  red  powder,  because  the 
color  is  thus  apt  to  become  of  a  dull  orange  hue.  The  fine  crystalline  powder  subsides  so 
quickly  to  the  bottom  after  every  ablution,  that  the  above  precaution  may  be  easily 
observed. 

CHROME  IROX.  The  only  ore  of  chromium  which  occurs  in  sufficient  abundance  for 
the  purposes  of  art,  is  the  octohedral  chrome  ore,  commonly  called  chromate  of  iron,  though 
it  is  rather  a  compound  of  the  oxides  of  chromium  and  iron.  The  fracture  of  this  mineral  is 
imperfect  conchoidal,  or  uneven.  Hardness=5'5  ;  specific  gravity  4-4  to  4-5  ;  but  the 
usual  chrome  ore  found  in  the  market  varies  from  3  to  4.  Its  lustre  is  semi-metallic  or 
resinous  ;  color,  iron,  or  brownish  black  ;  streak,  yellowish  to  reddish  brown.  It  is  some- 
times magnetic.  Before  the  blowpipe  it  is  infusible  alone,  but  in  borax  it  is  slowly  soluble, 
forming  a  beautiful  emerald  green  bead ;  fused  with  nitre  it  forms  a  yellow  solution  in 
water. 

Chrome  ore  was  first  discovered  in  the  Var  department  in  France ;  it  is  also  found  in 
Saxony,  Silesia,  Bohemia,  and  Styria ;  in  Norway  at  Roraas ;.  in  the  Ural  near  Katherinen- 
berg ;  in  the  United  States  at  the  Barehills  near  Baltimore,  Chester  in  Massachusetts,  and 
Hoboken  in  New  Jersey.  In  Scotland  it  is  found  in  the  parishes  of  Kildrum  and  Towie  in 
Aberdeenshire  ;  in  the  limestone  near  Portsoy  in  Banffshire  ;  near  Ben  Lawes  in  Perthshire, 
and  at  Buchanan  in  Stirlingshire.  It  occurs  massive  and  in  considerable  quantity  at  Swi- 
naness,  and  Haroldswick  in  Unst,  one  of  the  Shetlands ;  also  in  Fetlar  and  in  other  of  the 
smaller  Shetland  Islands. 

Composition  of  Chrome  Iron  Ores. 


1. 

2. 

3. 

4. 

1 
5. 

Sesquoxide  of  Chromium 
Protoxide  of  Iron 

Alumina 

Magnesia      -         .         .         .         - 
Sihca    --...- 

3G-0 
37 -0 
21-5 

5  0 

54-08 

25-C6 

9-02 

5-36 

4-83 

39-51 
86-00 
13-00 

10-60 

60-04 

20-13 

11-85 

7-45 

43-00 
34-70 
20-30 

200 

99-5 

98-95 

99-11 

99-47 

100-00 

(1)  From  St.  Dotninfro,  nnalyzftil  by  Berthier;  (2)  from  Riiraas,  in  Norway,  nn.ilyzcd  by  Von  Kobell; 
(3)  from  Baltimore,  analyzed  by  Soybert;  (4)  cryslallizcd,  from  Baltimore,  analyzed  by  Abiob;  (5)  ana- 
lyzed by  Klaproth. 


336  CHKOME  IRON. 

The  chief  application  of  this  ore  is  to  the  production  of  Chromate  of  Potash,  from  which 
salt  the  various  other  preparations  of  this  metal  used  in  the  arts  are  obtained. 

Treatment  of  the  Ore. — According  to  the  old  method,  it  is  reduced  to  a  fine  powder,  by 
being  ground  in  a  mill  under  ponderous  edge  wheels,  and  sil'ted.  It  is  then  mixed  with 
one  third  or  one  half  its  weight  of  coarsely-bruised  nitre,  and  exposed  to  a  powerl'ul  heat 
for  several  hours,  on  a  reverberatory  hearth,  where  it  is  stirred  about  occasionally.  In  the 
large  manufactories  of  this  country,  the  ignition  of  the  above  mixture  in  pots  is  laid  aside 
as  too  operose  and  expensive.  The  calcined  matter  is  raked  out  and  lixiviated  with  water. 
The  bright  yellow  solution  is  then  evaporated  briskly,  and  the  chromate  of  potash  falls 
down  in  the  form  of  a  granular  salt,  which  is  lifted  out,  from  time  to  time,  from  the  bottom 
with  a  large  ladle,  perforated  with  small  holes,  and  thrown  into  a  draining  box.  The  saline 
powder  may  be  formed  into  regular  crystals  of  neutral  Chromate  of  Potash,  by  solution  in 
water  and  slow  evaporation  :  or  it  may  be  converted  into  a  more  beautiful  crystalline  body, 
the  bichromate  of  potash,  by  treating  its  concentrated  solution  with  nitric,  muriatic,  sul- 
phuric, or  acetic  acid,  or  indeed  any  acid  exercising  a  stronger  aflSnity  for  the  second  atom 
of  the  potash,  than  the  chromic  acid  does. 

The  first  great  improvement  in  this  manufacture  was  the  dispensing  with  nitre,  and 
oxidizing  entirely  by  means  of  air  admitted  into  the  reverberatory  furnace,  in  which  the  ore 
mixed  with  carbonate  of  potash  is  calcined.  Stromeyer  afterwards  suggested  the  addition 
of  lime,  by  which  the  oxidation  was  much  quickened,  and  Mr.  Charles  Watt  substituted  the 
sulphates  of  potash  and  soda  for  the  nitrates  of  those  alkalies.  The  sulphate  was  first  inti- 
mately mixed  with  the  ground  ore,  and  then  the  lime  well  incorporated  with  the  mixture, 
which  was  heated  to  bright  redness  for  four  hours,  with  frequent  stirring. 

In  1847  Mr.  Tighman  obtained  a  patent  for  the  use  of  felspar  in  the  manufacture  of  cer- 
tain alkaline  salts,  and  amongst  them  of  chromate  of  potash  :  he  directs  4  parts  by  weight 
of  felspar,  4  parts  of  lime,  or  an  equivalent  quantity  of  carbonate  of  lime,  and  one  part  of 
chromic  ore,  all  in  fine  powder,  to  be  intimately  mixed  together,  and  kept  at  a  bright  red 
heat  for  from  18  to  20  hours  in  a  reverberatory  furnace,  the  mixture  being  turned  over 
frequently,  so  that  all  parts  may  be  exposed  equally  to  heat  and  air ;  the  temperature  is  not 
to  rise  high  enough  to  cause  even  incipient  fusion,  and  the  charge  should  be  kept  in  a 
porous  state  ;  when,  on  being  examined,  the  charge  is  found  to  contain  the  proper  quantity 
of  alkaline  chromate,  it  is  withdrawn  from  the  furnace,  and  lixiviated  with  water. 

Mr.  Swindell  mixes  the  powdered  ore  with  an  equal  weight  of  common  salt,  muriate  of 
potash,  or  hydrate  of  lime,  and  exposes  the  mixture  to  a  full  red  heat,  passing  over  it  while 
in  fusion  highly  heated  steam,  and  stirring  it  every  10  or  15  minutes;  the  hydrochloric  acid 
and  iron  escape  in  the  form  of  sesquichloride  of  iron. 

In  treating  chromium,  (chromate  of  iron,)  the  ore  is  pulverized  and  mixed  with  common 
salt,  muriate  of  potash,  or  hydrate  of  lime,  and  exposed  in  a  reverberatory  furnace  to  a  red 
or  even  a  white  heat,  the  mixture  being  stirred  every  ten  or  fifteen  minutes,  and  steam  at  a 
very  elevated  temperature  introduced  during  the  operation,  until  the  desired  effect  is  ob- 
tained, which  may  be  ascertained  by  withdrawing  a  portion  from  tlie  furnace  and  testing  it, 
as  customary.  The  products  of  this  operation  ai-e  finally  treated  in  the  manner  usual  for  the 
chromic  and  bichromic  salts. 

The  mixture  of  chromium  and  common  salt  produces  chromate  of  soda,  the  greater  por- 
tion, or  perhaps  all  of  the  iron  contained  in  the  chromium  being  absorbed  by  the  hydro- 
chloric acid  evolved  from  the  salt,  and  carried  off  in  the  form  of  sesquichloride  of  iron. 
From  the  first  mixture  is  manufactured  pure  bichromate  of  soda,  which,  by  the  addition  of 
hydrochloric  acid,  may  be  coiTverted  to  chlorochromate  ;  and  from  the  last,  or  lime  mix- 
ture, is  produced  a  chromate  of  that  earth,  from  which,  by  the  addition  of  soda  or  potash, 
there  may  be  obtained  a  compound  salt,  which,  with  those  previously  mentioned,  may  be 
advantageously  employed. 

M.  Jacquelin  first  prepares  chromate  of  lime  by  calcining  at  a  bright  red  heat  in  a  rever- 
beratory furnace,  for  9  or  10  hours,  an  intimate  mixture  of  chalk  and  chrome  ore.  The 
friable  and  porous  mass  is  then  crushed,  suspended  in  water,  and  sulphuric  acid  added  until 
the  liquid  .sliglitly  reddens  blue  litmus  paper ;  the  chromate  of  lime  is  hereby  converted 
into  bichromate  ;  chalk  is  now  added,  until  the  whole  of  the  scsquioxide  of  iron  is  precipi- 
tated, and  the  clear  liquid,  which  now  contains  only  bichromate  of  lime  and  a  little  sulphate, 
may  be  used  for  the  preparation  of  the  insoluble  chromates  of  lead,  zinc,  baryta,  &c.,  by 
mixing  it  with  the  acetates  or  chlorides  of  these  metals.  To  prepare  bichromate  of  potash, 
the  bichromate  of  lime  is  mixed  with  solution  of  carbonate  of  potash,  which  gives  rise  to 
insoluble  carbonate  of  lime,  which  is  easily  washed,  and  a  solution  of  bichromate  of  potash 
which  is  concentrated  and  set  aside  to  crystallize. 

Mr.  Booth  (patent  sealed  Nov.  9th,  1852)  mixes  powdered  chrome  ore  with  one-fifth 
of  its  weight  of  powdered  charcoal,  and  heats  it  on  the  hearth  of  a  reverberatory  furnace, 
protecting  it  carefully  from  the  air.  The  ore  is  by  this  means  decomposed,  and  the  iron 
reduced  to  the  metallic  state,  and  is  dissolved  out  by  dilute  sulphuric  acid  ;  the  residue  is 
washed  and  dried,  and  afterwards  mixed  with  carbonate  of  potash  and  saltpetre,  and  heated 


CHROMIUM,  OXIDE  OF.  337 

in  the  same  manner  that  the  chrome  ore  itself  is  heated  in  the  process  usually  employed. 
The  solution  of  sulphate  of  iron  is  evaporated  to  crystallization  so  as  to  produce  copperas  in 
a  state  adapted  for  commerce. 

Anahjsis  of  Chrome  Iron  Ore. — Various  methods  have  been  proposed.  The  following, 
suggested  by  Mr.  T.  S.  Hunt,  gives  accurate  results : — The  ore,  finely  levigated  in  an  agate 
mortar,  is  mi.^ed  with  10  or  12  times  its  weight  of  fused  bisulphate  of  potash,  and  preserved 
at  a  gentle  heat  for  about  half  an  hour.  The  fused  mass  is  extracted  with  hot  water,  and 
boiled  for  a  few  minutes  with  excess  of  carbonate  of  soda ;  the  precipitate  is  dried  and 
fused  with  five  times  its  weight  of  a  mixture  of  equal  parts  of  nitre  and  carbonate  of  soda, 
in  a  platinum  or  silver  crucible.  The  mixture  is  kept  in  fusion  for  10  or  15  minutes,  and 
when  cold,  is  extracted  with  water.  Tiie  alkaline  chromate  thus  obtained  may  be  precipi- 
tated by  a  salt  of  lead,  or  it  may  be  supersaturated  by  hydrochloric  acid,  and  boiled  with 
alcohol,  by  which  it  is  converted  into  chloride  of  chromium,  from  which  the  oxide  is  to  be 
precipitated  by  adding  ammonia  in  excess  and  boiling  for  a  few  minutes.  Ghi'ome  iron  ore 
is  so  difficult  of  decomposition,  that  the  method  of  fusing  it  at  once  with  nitre  and  an 
alkaline  carbonate  frequently  fails  in  oxidizing  the  whole  of  the  chromium  into  chromic 
acid. 

Mr.  Calvert  mixes  the  well-pulverized  ore  with  three  or  four  times  its  weight  of  a  mix- 
ture made  by  slaking  quicklime  with  caustic  soda,  and  then  dries  and  calcines  the  mass. 
He  then  adds  one-foUrth  part  of  nitrate  of  soda,  and  calcines  for  two  hours  more,  by  which 
time  he  finds  the  whole  of  the  chromium  is  converted  into  chromic  acid.  Another  process, 
which  Mr.  Calvert  finds  to  produce  good  results,  consists  in  calcining  the  pulverized  chrome 
ore  with  nitrate  of  baryta,  adding  a  little  caustic  potash  from  time  to  time  towards  the  end 
of  the  process. — H.  M.  N. 

CHROMIC  ACID.  There  are  several  methods  of  preparing  this  acid  ;  the  simplest  con- 
sists in  decomposing  bicliromate  of  potash  by  oil  of  vitriol : — 1.  An  excess  of  oil  of  vitriol 
is  mixed  with  a  warm  solution  of  bichromate  of  potash,  the  liquid  is  poured  off  from  the 
chromic  acid,  which  separates  in  small  red  crystals ;  the  crystals  .are  drained  in  a  funnel 
having  its  stem  partly  filled  with  coarsely  pounded  glass,  and  are  afterwards  dried  on  a 
porous  tile  under  a  bell-glass.  2.  Mr.  Warrington  mixes  10  measures  of  a  cold  saturated 
solution  of  bichromate  of  potash  with  from  12  to  15  measures  of  oil  of  vitriol  free  from 
lead,  and  presses  the  red  acicular  crystals,  wliich  separate  as  tlie  liquid  cools,  between  porous 
stones.  If  it  be  desired  to  remove  the  last  traces  of  sulphuric  acid,  the  crystals  should  be 
redissolved  in  water,  and  a  solution  of  bichromate  of  baryta  should  be  added  in  quantity 
just  sufficient  to  throw  down  the  whole  of  the  sulphuric  acid  as  sulphate  of  baryta ;  the 
solution  may  be  recrystallized  by  evaporation  in  vacuo.  3.  Meissner  prepares  the  acid  direct 
from  chromate  of  baryta  by  digesting  that  salt  with  a  quantity  of  dilute  sulphuric  acid,  not 
sufficient  for  complete  saturation  ;  the  solution  which  contains  chromic  acid  and  acid  chro- 
mate of  baryta  is  precipitated  by  the  exact  amount  of  sulplmric  acid  required,  so  that  the 
solution  is  neither  aifected  by  sulphuric  acid,  nor  by  a  salt  of  baryta  ;  it  is  then  evaporated 
to  dryness. 

CHROMIUM.  The  metallic  base  of  the  oxide  of  chromium.  It  may  bo  obtained  by 
exposing  to  a  very  high  temperature,  in  a  crucible  lined  with  charcoal,  an  intimate  mixture 
of  sesquioxide  of  chromium  and  charcoal.  The  spongy  mass  obtained  is  powdered  in  an 
iron  mortar  and  mixed  with  a  little  more  sesquioxide  of  chromium,  (to  oxidize  as  much  as 
possible  of  the  carbon ;)  it  is  then  again  exposed  in  a  porcelain  crucible  to  a  very  high  tem- 
perature, when  a  coherent  metal  is  obtained.  This  metal  is  grayish  in  color,  hard,  and 
brittle,  and  is  magnetic  at  low  temperatures.     It  has  received  no  practical  applications. 

CHROMIUM,  OXIDE  OF.  Tlie  green  oxide  of  chromium  has  come  so  extensively  into 
use  as  an  enamel  color  for  porcelain,  that  a  fuller  account  of  the  best  modes  of  manufactur- 
ing it  must  prove  acceptable  to  many  of  our  readers. 

That  oxide,  in  combination  with  water,  called  the  hydrate,  may  be  economically  prepared 
by  boiling  chromate  of  potash,  dissolved  in  water,  with  half  its  weight  of  flowers  of  sulphur, 
till  the  resulting  green  precipitate  ceases  to  increase,  which  may  be  easily  ascertained  hy 
filtering  a  little  of  the  mixture.  The  addition  of  some  potash  accelerates  the  operation. 
This  consists  in  combining  the  sulphur  with  the  oxygen  of  tlie  chromic  acid,  so  as  to  form 
sulphuric  acid,  which  unites  with  the  potash  of  the  chromate  into  sulphate  of  potash,  while 
tlie  chrome  oxide  becomes  a  hydrate.  An  extra  ((uantity  of  potash  facilitates  the  deoxi- 
dizement  of  the  chromic  acid  by  the  formation  of  hyposulphite  and  sulphurct  of  potash, 
l)i)th  of  which  have  a  strong  attraction  for  oxygen.  For  this  purjjose  the  dear  lixivium  of 
the  cln-omate  of  potash  is  sufficiently  pure,  though  it  should  hold  some  alumina  and  silica  in 
'solution,  as  it  generally  does.  Tlic  hydrate  may  be  freed  from  particles  of  sulphur  by 
heating  dilute  sulphuric  acid  upon  it,  which  dissolves  it;  after  which  it  may  be  precipitated, 
in  the  state  of  a  carbonate,  by  carl)onato  of  potash,  not  added  in  excess. 

By  calcining  a  mixture  of  bichromate  of  potasli  and  sulphur  in  a  crucible,  chromic  acid 
is  also  decomposed,  and  a  liydratcd  oxide  may  also  be  obtained ;  the  sulphur  being  partly 
ronverted  into  sulphuret  of  potassium,  and  partly  into  sulphuric  acid,  (at  the  expense  of  the 
You  Tir.— 22 


338  CHEOMIUM,  BLUE  OXIDE  OF. 

chromic  acid,)  which  combines  with  the  rest  of  the  potash  into  a  sulphate.  By  careful  lixi- 
viation,  these  two  new  compounds  may  be  washed  away,  and  the  chrome  green  may  be  freed 
from  the  remaining  sulphur  by  a  slight  heat. 

Preparation  of  Green  Oxide  of  CItromium  for  Calico-printing. — The  following  direc- 
tions are  given  by  De  Kerrur :  At  the  commencement  of  the  process  the  green  hydrate  of 
the  oxide  of  chromium  is  first  prepared  by  dissolving  4  kilogrammes  of  bichromate  of  pot- 
ash in  22  litres  (39  pints)  of  boiling  water.  Then  into  a  boiler  or  vessel  containing  108 
litres  (24  gallons)  of  boiling  water,  4  or  5  kilogrammes  (8  or  10  lbs.)  of  pulverized  white 
arsenic  are  thrown,  and  boiled  for  10  minutes ;  a  precii)itate  will  be  formed,  and  must  be 
allowed  to  settle  :  the  clear  liquor  is  then  run  off,  and  immediately  mixed  with  the  solution 
of  bichromate  of  potash,  stirring  all  the  time  :  in  a  short  time  the  mixture  acquires  a  green 
tint,  and  the  hydrated  oxide  of  chromium  will  be  formed  and  precipitated.  After  being 
several  times  well  stirred,  and  allowed  to  cool,  the  whole  is  thrown  upon  a  filter  of  white 
wool,  and  the  hydrate  of  chromium  remaining  on  the  filter  is  carefully  washed  with  boiling 
water.  It  is  then  dried,  and  ready  to  be  employed  for  the  preparation  of  the  chloride.  In 
order  to  obtain  that  salt,  hydrochloric  acid  of  22°  Bcaume  is  diluted  with  water,  until  the 
acid  no  longer  gives  off  vapor.  It  is  then  heated,  and,  whilst  hot,  as  much  of  the  hydrated 
oxide  of  chromium,  prepared  as  above,  is  added  as  will  saturate  the  acid  and  leave  a  slight 
excess  of  the  oxide  undissolved.  The  whole  is  then  left  to  settle,  and  the  clear  liquor  is 
decanted  from  the  dissolved  matter.  In  this  state  the  solution  of  chloride  of  chromium  still 
presents  some  traces  of  free  acid,  which  would  act  injuriously  upon  the  fibres  of  the  cotton. 
To  remove  this,  and  to  obtain  the  product  in  a  neutral  state,  potash  lye  (marking  36' 
Beaume)  is  poured  in  very  gradually,  until  the  oxide  of  chromium  begins  to  be  precipitated. 
The  solution  of  chloride  of  chromium  thus  prepared,  and  which  is  of  a  dark  green  color,  is 
evaporated  until  it  marks  46°  Beaume;  after  cooling,  oxide  of  chromium  of  the  finest  green 
color  is  obtained.     This  preparation  is  sold  under  the  name  of  Sea  green. 

This  oxide  may  also  be  prepared  by  decomposing,  with  heat,  the  chromate  of  mercury, 
a  salt  made  by  adding  to  nitrate  of  protoxide  of  mercury,  chromate  of  potash,  in  equivalent 
proportions.  This  chromate  has  a  fine  cinnabar  red,  when  pure  ;  and,  at  a  dull  red  heat, 
parts  with  a  portion  of  its  oxygen  and  its  mercurial  oxide.  From  M.  Dulong's  experiments 
it  would  appear  that  the  purest  chromate  of  mercury  is  not  the  best  adapted  for  preparing 
the  oxide  of  chrome  to  be  used  in  porcelain  painting.  He  thinks  it  ought  to  contain  a  little 
oxide  of  manganese  and  chromate  of  potash  to  afford  a  green  color  of  a  fine  tint,  especially 
for  pieces  that  are  to  receive  a  powerful  heat.  Pure  oxide  of  chrome  preserves  its  color 
well  enough  in  a  muffle  furnace  ;  but,  under  a  stronger  fire,  it  takes  a  dead-leaf  color. — H. 
M.N. 

CHROMIUM,  BLUE  OXIDE  OF.  The  following  directions  have  been  given  for  the 
preparation  of  a  blue  oxide  of  chromium :  The  concentrated  alkaline  solution  of  chromate 
of  potash  is  to  be  saturated  with  weak  sulphuric  acid,  and  then  to  every  8  lbs.  is  to  lie 
added  1  lb.  of  common  salt,  and  half  a  pound  of  concentrated  sulphuric  acid ;  the  liquid 
will  now  acquire  a  green  color.  To  be  certain  that  the  yellow  color  is  totally  destroyed,  n 
small  quantity  of  the  liquor  is  to  have  potash  added  to  it,  and  filtered  ;  if  the  fluid  is  still 
yellow,  a  fresh  portion  of  salt  and  of  sulphuric  acid  is  to  be  added  :  the  fluid  is  then  to  be 
evaporated  to  dryness,  redi.ssolved,  and  filtered  ;  the  oxide  of  chrome  is  finally  to  be  precip- 
itated by  caustic  potash.  It  will  be  of  a  greenish-blue  color,  and,  being  washed,  must  be 
collected  upon  a  filter. — H.  M.  N. 

CIIRYSOBERYL,  or  GOLDEN"  BERYL,  is  composed  of  alumina  80-2  and  glucina  19-8 
=  luO.  It  is  of  various  shades  of  yellowish  and  light  green,  sometimes  with  a  bluish  opa- 
lescence internally.  It  has  a  vitreous  lustre,  and  varies  from  translucent  to  transparent. 
Fracture,  conchoidal  or  uneven.  Specific  gravity  =  3 '5  to  3-S.  It  belongs  to  the  trime- 
tric  system. 

This  stone,  when  transparent,  furnishes  a  beautiful  gem  of  a  yellowish-green  color,  which 
is  cut  with  facets,  unless  it  be  opalescent,  in  which  case  it  is  cut  en  cahochon.  It  occurs  in 
the  Brazils  and  Ceylon,  in  rolled  pebbles  in  the  alluvial  deposits  of  rivers ;  in  the  Ural,  in 
mica-slate ;  and  at  Haddam,  Connecticut,  L^.  S.,  in  granite,  traversing  gneiss. — H.  W.  B. 

CHRYSOLITE,  or  PERIDOT.  The  name  given  to  the  paler  and  more  transparent 
crystals  of  olivine,  the  latter  name  being  restricted  to  imbedded  masses  or  grains  of  inferior 
color  and  clearness.  It  is  usually  found  in  angular  or  rolled  pieces,  rarely  crystallized.  The 
cry.stals  (generally  8,  10,  or  12-sided  prisms)  arc  variously  terminated,  and  often  so  com- 
pressed as  to  become  almost  tabular.  They  are  generally  very  fragile,  and  therefore  unfit 
for  ornamental  purposes.  Oriental  chrysolite  is  composed  of  silica  89-'73,  magnesia  50-13, 
protoxide  of  iron  9-19,  alumina  0-22,  protoxide  of  manganese  0-09,  oxide  of  nickel  0-32  = 
99 -eS. — Stromeyer. 

As  a  gem,  chrysolite  is  deficient  in  hardness  and  play  of  color ;  but  when  the  stones  are 
large  and  of  good  color,  and  well  cut  and  polished,  it  is  made  into  necklaces,  A'c,  with  good 
effect.  From  its  softness,  which  is  little  less  than  that  of  glass,  it  requires  to  be  worn  with 
care,  or  it  will  lose  its  polish.     The  best  mode  of  displaying  the  colors  to  the  greatest  ad- 


CLOVE  OIL.  339 

vantage  is  to  cut  it  in  small  steps.  To  give  it  the  highest  polish,  a  copper  wheel  is  used,  on 
which  a  little  sulphuric  acid  is  dropped.  During  the  process,  a  highly  suftbcating  smell  is 
given  out,  produced,  probably,  by  the  oxidation  of  the  copper  and  the  decomposition  of  the 
acid.  Chrysolite  is  supposed  to  have  been  the  topaz  of  the  ancients.  It  is  found  near 
Constantinople  ;  at  Vesuvius  ;  and  the  Isle  of  Bourbon,  at  Real  del  Monte  ;  in  Mexico  ;  in 
Egypt ;  and  at  Expailly,  in  Auvergne. — II.  W.  B. 

CHRYSOPRASE.  An  apple-green  or  leek-green  variety  of  chalcedony,  the  color  of 
which  is  caused  by  the  presence  of  nickel.  It  occurs  at  Kosemeitz,  in  Silesia,  and  Belmont's 
lead  mine,  St.  Lawrence  County,  New  York. 

This  stone  was  probably  the  chrysoberyl  t)f  the  ancients. — H.  W.  B. 

CINCHONICINE.  C""H-*N^0-.  An  alkaloid  isomeric  with  cinchonine  and  cinchoni- 
dine.  It  is  produced  by  the  action  of  heat  on  any  of  the  saline  combinations  of  cinchonine. 
{Pasteur.)  To  obtain  cinchonicine,  it  is  only  necessary  to  add  a  small  quantity  of  water 
and  sulphuric  acid  to  sulphate  of  cinchonine,  and,  after  driving  off  all  the  water  at  a  low 
temperature,  to  keep  the  salt  for  a  few  hours  at  a  temperature  between  250'  and  2*70'. 
The  product  is  pure  sulpliate  of  cinchonicine.  By  a  similar  reaction  quinine  becomes 
converted  into  quinicine ;  quinidine  also  is  susceptible  of  a  similar  metamorphosis. — C. 
G.  W. 

CINCHONIDINE.  C"ff'N-0'.  This  alkaloid,  the  quinidine  of  Leers,  is  one  of  the 
isomers  of  cinchonine.  There  is  much  confusion  to  be  found  in  works  on  the  cinchona  al- 
kaloids, partly  arising  from  the  troublesome  system  of  giving  them  names  greatly  resembling 
each  other,  and  partly  from  mixtures  having  been  analyzed  under  the  impression  of  their 
being  pure  bases.  For  some  remarks  on  this  subject,  see  Quinidine.  Cinchonidine  was 
first  noticed  by  Winckler ;  it  is  found  accompanied  by  a  little  quinine  in  the  Cinchona  Bo- 
gota, also  in  that  of  Macaralbo.  For  the  reactions  of  cinchonidine,  and  its  associated  bases 
with  chlorine  water  and  ammonia,  see  Quinine. — C.  G.  W. 

CINCHONINE.  C^°H"N^O^.  An  alkaloid  or  organic  base  accompanying  quinine.  In 
consequence  of  its  being  considered  less  febrifuge  than  quinine,  it  is  alwaj's  carefully  re- 
moved from  the  latter.  Some  of  the  differences  of  properties  on  which  processes  for  their 
separation  may  be  founded  arc  the  following :  Cinchonine  crystallizes  more  readily  than 
quinine  from  an  alcoholic  solution,  in  consequence  of  its  being  less  soluble  in  that  fluid. 
Sulphate  of  quinine,  on  the  other  hand,  is  less  soluble  than  sulphate  of  cinchonine.  Cin- 
chonine is  insoluble,  while  quinine  is  freely  soluble  in  ether.  Cinchonine  forms  a  great 
number  of  salts,  which  for  the  most  part  are  well  defined,  and  crystallize  readily.  It  is  not 
so  bitter  as  quinine.  In  cold  water  it  is  quite  insoluble,  and  even  when  boiling,  2,500  parts 
are  required  to  dissolve  one  of  cinchonine.  Laurent  has  studied  the  action  of  the  halogens 
on  it  at  considerable  length,  but  there  are  several  points  connected  with  this  portion  of  their 
history  which  requires  re-investigation.  Treated  with  potash  at  a  high  temperature,  a  basic 
fluid  is  obtained,  formerly  considered  to  be  pure  chinoline,  but  which  has  been  shown  by 
the  author  of  this  article  to  contain  pyrrol,  all  the  pyridine  series,  chinoline,  and  a  new 
base,  lepidine. — C.  G.  W. 

CINNABAR,  is  the  principal  and  only  valuable  ore  of  the  mercury  of  commerce,  which 
is  prepared  from  it  by  sublimation. 

It  is  a  sulphide  {xnlphurct)  of  mercury,  composed,  when  pure,  of  quicksilver  86-2,  sul- 
phur, 13 "8,  in  which  case  it  is  a  natural  vermilion,  and  identical  with  the  vermilion  of 
commerce  ;  but  it  is  sometimes  rendered  impure  by  an  admixture  of  cl.ay,  bitumen,  oxide 
of  iron,  &c.  Cinnabar  is  of  a  cochineal  red  color,  often  inclining  to  brownish-red,  and  lead- 
gray,  wich  an  adamantine  lustre,  approaching  to  metallic  in  dark'  varieties,  and  to  dull  in 
Iriable  ones.  It  varies  from  sub-transparent  to  opaque,  has  a  scarlet  streak,  and  breaks 
with  a  sub-conchoidal  uneven  fracture.  H  =  2  to  2'5,  specific  gravity  =  8'90.  In  a  matrass 
it  entirely  sublimes,  and  with  soda  yields  mercury  with  the  evolution  of  sulphurous  fumes. 
When  crystallized,  it  belongs  to  the  rhombohedral  system. 

Cinnabar  occurs  in  beds  in  slate-rocks.  The  chief  European  beds  are  at  Almaden  near 
Cordova,  in  Spain,  and  at  Idria  in  Upper  Carinthia,  where  it  usually  occurs  in  a  massive 
form,  and  is  worked  on  a  thick  vein  belonging  to  the  Alpine  carboniferous  strata.  It  also 
occurs  abundantly  in  China,  .Japan,  Fluanca  Vilica  in  South  Peru,  and  at  New  Almaden 
in  California,  in  a  mountain  east  of  San  Jose,  between  the  Bay  of  Francisco  and  Mon- 
terey where  it  is  very  abundant,  and  easy,  of  access.  The  chief  source  of  the  mercury 
used  in  England  is  Spain,  whence  10  cwt.  of  cinnabar  and  11,544  lbs.  were  imported  in 
1857. 

Cinnabar  in  the  arts  is  used  as  a  pigment,  in  the  state  of  a  fine  powder,  which  is  known 
by  the  name  of  vermilion.     Sec  Vermilion. — II.  W.  B. 

CLOVE  OIL.  (C'°II'^0\  Siin.  Euqmic  acid,  Caropkyllic  acid.)  When  cloves  are 
distilled  with  water,  a  large  quantity  of  oil  passes  over.  It  has  been  examined  by  Dumas, 
Ettling,  Bockmann,  Stenhouse,  Calvi,  and,  more  recently,  by  Greville  Williams.  Treated 
with  solution  of  potash,  the  greater  portion  dissolves,  leaving  a  small  quantity  of  a  hydro- 
carbon isomeric  with  oil  of  turpentine.     See  Carbl'retted  Hydrogen.     The  potash  soiu- 


340 


COAL. 


tion,  on  being  supersaturated  with  a  mineral  acid,  allows  the  eugenic  acid  to  rise  to  the  sur- 
face in  the  form  of  an  oil.  When  freshly  distilled  it  is  colorless,  and  boils  at  483°  S.  Its 
density  at  57 "•2  F.  is  1-0684.     On  analysis  it  gave  : — 


Greville  Williams. 


Carbon  - 
Hydrogen 
Oxygen   - 


73-1     73-1 

7-7       7-6 

19-2     19-3 

100-0  lOO-O* 


Calculation. 

C'-"' 

120 

73-17 

H'« 

12 

7-32 

0^ 

32 

19-51 

100-00 


The  density  of  its  vapor  was  found  to  be  5-86,  Theory  requires  5-67.  The  above 
results  were  confirmed  bv  a  determination  of  the  percentage  of  baryta  in  the  eugenate. 
— C.  G.  W. 

COAL.  The  coal  fields  of  the  United  Kingdom  are  the  most  important  of  any  worked 
in  the  world.  Their  production  has  been  variously  estimated  as  being  between  thirty-one 
and  fifty-four  millions  of  tons  annually.  It  has  now  been  determined  by  inquiries  carefully 
made  by  the  Keeper  of  Mining  Records  that  these  amounts  were  far  exceeded,  as  is  shown 
by  the  following  returns  : — 


Tons. 

Tons. 

Tons. 

Tons. 

1854. 

1S55. 

1S56. 

185T. 

Northumberland  and  Durham 

15,420,615 

15,431,400 

15,492,969 

15,826,525 

Cumberland           .... 

887,000 

809,549 

913,891 

942,018 

Yorkshire     -         -         -         -         - 

7,260,500 

7,747,470 

9,083,625 

8,875,440 

Derbyshire   -         -         -         -         - 

Nottinghamshire  -         -         -         - 

2,406,696 
813,474 

2,256,000 
809,400 

[3,293,325 

3,687,442 

Warwickshire       .         .         .         - 

255,000 

262,000 

835,000 

398,000 

Leicestershire       .... 

439,000 

425,000 

632,478 

698,750 

Staffordshire  and  Worcestershire  - 

7,500,000 

7,323,000 

7,305,500 

7,164,625 

Lancashire  .         .         -         -         - 

9,080,500 

8,950,000 

8,950,000 

8,565,500 

Cheshire 

786,500 

755,500 

754,327 

750,500 

Shropshire 

1,080,000 

1,105,250 

752,100 

750,000 

Gloucester,  Somersett  and  Devon 

1,49-2,366 

1,430,620 

1,530,000 

1,225,000 

Wales 

9,643,000 

9,677,270 

9,965,600 

8,178,804 

Scotland        .         .         .         - 

7,448,000 

7,325,000 

7,500,000 

8,211,473 

Ireland          .... 

148,750 

144,620 

136,635 

120,630 

64,661,401 

64,453,070 

66,645,450 

65,394,707 

The  total  number  of  collieries  in  the  United  Kingdom  being — 

England 1,943 

Wales 235 

Scotland 405 

Ireland          ......--.  71 


2,654 


The  di.'^tribtition  of  coal  in  the  United  Kingdom  is  one  of  vast  importance  to  the  coun- 
try. It  is  spread  over  large  areas,  commencing  with  Devonshire  in  the  south,  and  extend- 
ing to  the  northern  divisions  of  the  great  Scotch  coal-fields.  A  careful  examination  of  all 
these  deposits  cannot  but  prove  useful. 

Devonshire.  Lirfnite  of  Bovcy-Heathficld. — Lysons  {Marina  Britannia)  informs  us 
that  this  so-called  Bovey  coal  was  worked  for  use  early  in  the  last  century  ;  and  Dr.  Maton 
described  those  beds  in  1797  as  being  from  4  to  16  feet  in  thickness,  alternating  with  clay, 
and  he  stated  that  the  pits  were  about  80  feet  deep,  and  worked  for  the  supply  of  a  neigh- 
boring pottery.  A  pottery  was  established  at  Ideo  in  1772,  and  one  at  Bovey  Tracey  in 
1812,  both  of  which  were  supplied  with  fuel  from  those  lignite  beds.  Those  beds  are  sup- 
posed to  have  been  formed  towards  the  latter  part  of  the  supercretaceous  periods.  The 
wood  of  which  they  are  formed  has  been  sometimes  supposed  to  be  analogous  to  the  oak 
and  other  exi.sting  trees.  The  offensive  smell  emitted  by  this  lignite  when  burnt  has  always 
prevented  its  use  for  domestic  purposes,  except  among  the  poorer  cottages  of  the  neiglil)or- 
hood.  The  supply  from  those  beds  of  "  Bovey  coal  "  is  now  falling  off,  the  adjoining  pot- 
tery being  compelled  to  use  some  coal  as  fuel. — Be  la  Bcvhe. 

Bideford  Anthracite — The  beds  of  Anthracite  stretch  across  the  country  from  Barn- 
staple   Bay,  by  Bideford    and  Averdiscot,  towards    Cliittlehampton,  a  distance  of  about 


COAL. 


341 


ir,() 


twelve  miles  and  a  half.    The  anthracite  is  mixed  with  the  black  shales  of  the  carbonaceous 
deposits. 

"  The  anthracite  is  mixed  with  those  shales  in  the  manner  represented  beneath,/*/.  160 ; 

fl,  sandstones ;  6,  shales ;  c,  cuhn 
or  anthracite ;  so  that  the  culm 
itself  seems  the  result  of  irregular 
accumulations  of  vegetable  mat- 
ter intermingled  with  mud  and 
sand.  As  so  frequently  happens 
with  carbonaceous  deposits  of  this 
kind,  nodules  of  argillaceous  iron- 
stone are  often  found  in  the  same 
localities  with  the  shales  and  an- 
thracite, reminding  us  of  the 
intermixture  of  iron  ores  and 
vegetables  matters  in  the  bogs 
and  morasses  of  the  present  day." — De  la  Beche. 

Somersetshire  and  Gloucestershire. — The  Dean  Forest  coal-field,  and  the  coal  meas- 
ures, extending  further  south  forming  the  Bristol  coal-field,  are  included  in  this  division. 
The  workable  seams  of  coal  in  the  forest  are  the  following : — 

Dog  Delf  (having  a  thickness  of) 

Smith  Coal  " 

Little  Delf  '* 

Park  End  High  Delf  " 

Stakev  Delf  " 

Little  Coal  " 

Rocky  Delf  " 

Upper  Churchway  Delf  " 

Lower  Churchway  Delf  " 

Braizley  Delf  " 

Nag's  Head,  or  Weaver's  " 

Whittington  Delf  " 

Coleford  High  Delf 

Tipper  Trenchard  " 

Lower  Trenchard  " 

There  is  a  small  coal-field  north  of  the  Forest  of  Dean,  which  is  a  long  narrow  strip, 
containing  two  and  a  half  square  miles,  or  1,600  acres. — Mnclaicchlan,  Geological  Transac- 
tions ,vol.  V. 

About  nine  miles  and  a  half  to  the  south  of  Dean  Forest  a  considerable  mass  of  coal 
measures  has  been  preserved  from  destruction,  by  the  denuding  causes  which  have  carried 
off  the  connecting  portion  between  it  and  Dean  Forest,  leaving  at  least  two  outlying  patches 
on  the  north  of  Chepstow. 

The  Bristol  coal-field  occupies  about  fifty  square  miles,  or  32,000  acres.  The  seams 
of  coal  are  very  thin  in  comparison  with  those  which  are  worked  in  other  districts. 
Buckland  and  Coneybeare  (Geological  Transactions,  vol.  i.)  have  well  described  this  coal- 
field. 

The  total  thickness  of  the  whole  series  of  strata  in  this  Bristol  coal-field  has  been  shown 
by  De  la  Beche  to  be  as  follows : — 

Upper  shales  and  limestones  1,800  feet,  with  10  beds  of  coal. 
Middle  sandstone  1,725  feet,  with    5  beds  of  coal. 

Lower  shales  1,.565  feet,  with  36  beds  of  coal. 

Farewell  Rock  1,200  feet. 


ft. 

in. 

1 

2 

2 

6 

1 

8 

3 

n 

2 

6 

1 

1 

1 

9 

4 

2 

2 

0 

1 

9 

2 

9 

2 

6 

5 

0 

2 

0 

1 

4 

6,290 


SocTH  Wales  Coal-field. — The  total  thickness  of  the  coal  strata  in  this  important 
district  is  very  great.  Logan  and  De  la  Beche  have  accumulated  evidence  wliich  appoMrs 
to  justify  the  admission  of  11,000,  or  even  12,000  feet  thickness  from  the  carboniferous 
limestone  to  the  highest  part  of  the  coal  series  about  Llanelly  ;  in  other  parts  of  tlie  field 
the  series  is  found  to  lie  on  proportions  only  loss  gigantic.  The  most  general  view  which 
can  be  afforded  seems  thus,  giving  the  true  coal  measure  about  8,000  feet : — 

feet. 

Llanelly  scries,  with  several  beds  of  coal 1,000 

Penllergare  series  of  shales,  sandstones,  and  beds  of  coal,  110  beds  ; 

26  beds  of  coal 3,000 


342 


COAL. 


Central  series,  (Townhill  sandstones  of  Swansea,  Pennant  grit  of  the 
Bristol  field  ;)  62  beds,  and  IG  beds  of  coal 

Lower  shales,  coals,  and  iron-stones,  (Merthyr  ;)  2fi6  beds,  34  beds  of 
coal 

Abundance  of  iron-stone  beds  and  unionidce  occur. 

Farewell-Rock  and  Gower  shales  above  ;  the  carboniferous  limestone  below, 


246 


812 


The  coal  on  the  north-eastern  side  of  the  basin  is  of  a  coking  quality,  excellent  for  the 
iron  manufacture  ;  on  the  north-western  it  contains  little  or  no  bitumen,  being  what  is 
called  stone-coal  or  anthracite  ;  on  the  south  side,  from  Pontypool  to  Caermarthen  Bay,  it 
is  of  a  bituminous  or  binding  quality. — Phillips. 

Shropshire. — Tliis  district  includes  the  small  coal-field  of  Coalbrook  Dale,  and  that  of 
the  plain  of  Shrewsbury.  The  Coalbrook  Dale  field,  according  to  Mr.  Prcstwick,  has  some 
remarkable  features.  {Geological  Transactions.)  Perhaps  tliere  is  no  coal  track  known, 
which  in  so  small  a  compass,  about  twelve  miles  long,  and,  at  most,  three  and  a  half  miles 
wide,  exhibits  so  many  curvatures  in  the  outcrops,  crossed  by  so  many  continuous  faults, 
some  varying  north  by  east,  others  cast-north-east;  these  crossed  by  many  of  shorter 
length,  and  directed  west  north-west,  and  in  several  other  lines.  The  total  thickness  is 
supposed  to  be  1,000  or  1,100  feet,  divided  into  80  distinct  strata.  The  coal  varies  in  total 
thickness  from  16  feet  to  55,  and  in  the  number  of  its  beds  from  V  to  22,  the  increase  being 
to  the  north.  The  "  cleat  "  or  systems  of  joints  run  from  west-north-west  to  east-south- 
east. The  coal  is,  for  the  most  part,  of  the  variety  called  slate  coal  in  Scotland,  and  hard 
coal  in  Derbyshire.  Cannel  coal  is  rare — sulphureous  coal  (pyritous)  very  common.  Pe- 
troleum abounds  in  the  central  and  upper  part  of  the  field.  The  beds  are  mostly  thin  ;  the 
ten  uppermost  are  too  sulphureous  for  other  uses  than  lime-burning,  and  are  called  stinkers; 
twelve  beds  of  good  coal,  in  all  25  feet  thick,  the  thickest  being  five  feet,  succeed,  and 
the  lowest  bed  of  the  whole  formation,  eiglit  inches  thick,  is  sulphureous. — Phillips, 
Prcstwick. 

Staffordshire. — T7ic  coal-fcld  of  South  Staffordshire,  which  has  been  described  by 
Sir.  J.  Beete  Jukes,  who  states  its  boundary  would  be  roughly  described  as  the  space  in- 
cluded within  a  boundary  line  drawn  from  Rugeley  through  Wolverhampton  to  Stourbridge ; 
hence  to  the  southern  end  of  the  Bromsgrove  Lickey,  and  returning  through  Harborne 
(near  Birmingham)  and  Gre.at  Barr  back  to  Rugeley.  This  geologist  classes  these  coal  strata 
in  three  divisions,  by  the  well-traced  band  of  thick  coal.  The  total  thickness  of  coal  near 
Dudley  being  about  57  feet,  and  between  Bilston  and  Wolverhampton  upwards  of  70  feet. 
The  thick  coal  is  formed  of  eight,  ten,  or  thirteen  distinguishable  parts,  the  whole  seam 
varying  in  thickness  from  three  feet  to  thirty-nine  feet  five  inches;  it  is  very  irregular  in 
parts,  divided  by  sandstone,  splitting  with  wide-shaped  offshoots,  and  cut  into  "  swiles  "  or 
"  horse  backs,"  which  rise  up  from  the  floor.  Below  the  thick  coal  are  numerous  beds  of 
sandstone-shales,  coal,  and  iron-stone,  having  on  the  average  a  thickness  of  320  feet ;  and 
above  the  thick  coal  the  thickness  is  280  feet  on  the  average. — Records  of  the  School  of 
Mines. 

North  Staffordshire  Coalfield. — This  field  is  comprised  in  the  space  between  Congleton, 
Newcastle-under-Lyne,  and  Lane  End.  About  32  beds  of  coal  have  been  determined,  rising 
eastward  between  Burslem  in  the  centre  of  the  field  and  its  eastern  limit  near  IS'orton 
church. 

Derbyshirf,  and  Nottinghamshire. — The  Derbyshire  and  Nottinghamshire  coals  are 
classed  as  to  structure  in  two  varieties,  as  "  hard''''  coal,  in  which  the  divisional  structures 
are  chiefly  derived  from  the  planes  of  stratification,  crossed  by  one  set  of  "  cleat "  or 
natural  joints,  (called  "  slines,"  "  backs,"  &c.  )  so  that  large  prismatic  masses  result ;  "  soft  " 
coal,  where  the  cleat  fissures  are  numerous,  and  broken  by  cross  cleat.  In  respect  of  the 
qua,l'ity.  some  of  the  coal  is  of  a  "crozling"  or  coking  nature,  easily  fusible,  and  changing 
its  figure  by  "  coking  ;  "  the  rest,  (and  this  is  specially  the  case  with  the  "  hard  "  variety,) 
makes  both  good  furnace  coal  and  excellent  coke,  which,  however,  is  hardly  melted  at  all, 
and  the  masses  are  not  changed  in  figure  by  the  iirocess. — Phillips's  Manual  of  Geolofjxi. 

The  names  by  which  the  more  important  bods  of  coal  worked  within  this  district  are 
known,  are  as  follows :  Tupton  coal,  hard  coal,  soft  coal,  black  shale  or  clod  coal,  low  hard 
coal  and  low  soft,  windmill  coal,  Dansil  coal,  Canister  coal,  Parkgate  coal,  Aston  coal,  Kil- 
burn  coal,  furnace  coal.  Hazel  coal,  Eureka  coal,  main  and  deep  coal. 

Leicestershire  and  Warwickshire. — The  Leicester  coal-field  is  best  developed  about 
Ashby  de  la  Zouch,  (see  Mammatt  on  "  the  coal-field  of  Ashby  de  la  Zouch,")  where  the 
coal  is  much  like  the  hard  coal  of  Derbyshire.  Amongst  the  seams  of  coal  is  one  variety 
called  cannel ;  and  another,  formed  by  the  concurrence  of  more  than  one  band,  from  seven- 
teen to  twenty-one  feet  in  thickness.  The  beds  near  Ashby  de  la  Zouch  are  as  follows  : — 
In  the  Moira  district — 


COAL. 


343 


Eureka  coal 
Stocking  coal 
Woodfield  coal    - 
Slate  coal 
Nether  main  coal 
Fourfoot  coal 
The  Earl  coal      - 
In  the  Coleorton  district — 
Heath  End  coal 
Lount  coal 
Main  coal    - 


Thickness  of  beds. 
4  to  6  feet. 
6  to  7     " 
5 

3i  to  4  " 
14  to  15" 
4  to  5  " 
4  ft.  6  in. 

9  feet. 
(3  beds.) 

10  to  12  feet. 


The  Warwickshire  Coal-field  is  from  a  point  east  of  Tamworth  to  a  point  east  of  Coven- 
try, about  twenty  miles  from  N.  W.  to  S.  E.  parallel  to  the  Ashby  coal  tracts.  The  strata 
are  most  productive  of  coal  near  the  southern  extremity,  where  by  the  coming  together 
of  two  seams, — worked  separately  at  Griff", — the  five-yard  seam  is  worked.  The  beds  are 
known  as  the  seven-feet  coal  and  rider,  slate  coal,  two  yards,  lower  seam,  cannel,  and  Ell 
coal. 

Yorkshire. — Professor  John  Phillips  gives  the  following  mode  of  classification  as  the 
most  natural  and  convenient  for  the  Yorkshire  coal. 

Magnesian  limestone  unconformably  covers  the  coal  seams. 

Shales  and  Badsworth  coal.  • 

Ackworth  rock. 
Wragby  and  Sharlston  coals. 
Red  rock  of  WooUey  Hooton-Roberts,  &c. 
Furnace  coals 


Upper  coals 


Middle  coals  - 


Intermediate  coals 
Iron-stone  coals    - 


-    Barnsley  thick  coal. 

(  Rock  of  Horbury. 
"  \  Middle  coals. 

j  Silkstone  and  Flockton  beds. 
"  \  Low  Moor  coals. 

Flagstone  rock  of  Woodhouse,  Bradford,  Elland,  Peniston,  &c. 

C  Shales  and  ganister  stone. 
Coals. 
Lower  coals    -     \  Shales  and  ganister  stone. 
I  Coals. 
[Shales,  &c. 
Millstone  grit  lies  below  the  "coal  series." 

The  important  middle  coal  series  are  again  divided  by  Professor  Phillips  as  follows  :— 
Red  rock  of  Woolley  Edge. 

Furnace  coals  of  Barnsley,  &c.  including  the  eight  or  ten  feet  scam. 
Rock  of  Horbury  and  Wentworth  House. 

!  Swift  burning  coals  of  Middleton,  Dewsbury,  &c.,  with  bands  of 
"  mussels." 
Bituminous  coals  of  Silkstone  and  Low  Moor. 
Flagstone  rocks  beneath. 

The  small  coal-field  of  Ingleton  and  Black  Burton  in  Lonsdale  is  thrown  down  on  the 
south  side  of  the  great  Craven  fault. 

Lancashire. — The  coal-field  of  Lancashire  occupies  an  area  extending  from  Maccles- 
field to  Colne,  46  miles,  and  from  Torboch,  near  Liverpool,  to  Todmorden,  about  40  miles. 
Excluding  the  millstone  grit,  its  area  is  about  250  square  miles. — Ilei/wood. 

In  a  line  through  Worsley,  Bury,  and  Burnley  to  the  limestone  shales  of  Pendle  Hill, 
we  have  36  seams  of  coal,  10  of  them  not  exceeding  1  foot  in  thickness,  making  in  ail  93 
feet  of  coal. 

The  series  is  divisible  into  throe  parts  above  the  millstone  grit: 

Upper  part,  containing  a  bed  of  limestone  at  Ardwich  near  Manchester. 

Middle  part,  containing  the  greater  part  of  the  thick  and  v.aluable  seams,  especially  the 
cannel  coal  of  Wigan. 

Lower  part,  corresponding  to  the  ganister  series  of  Yorkshire. 

Cheshire. — The  coal-field  of  Cheshire  is  not  of  great  importance. 

North  Walk:s. — Piintuhire  and  Denbighshire. — The  Flintshire  coal  basin  extends  from 
north  to  south,  somewhat  more  than  30  miles  from  Llanassa  to  near  Oswestry  in  Shropshire. 
The  coal  strata  dip  generally  eastward  and  form  in  the  northern  part  a  trough  beneath  the 
estuary  of  the  Dee.  This  coal  basin  in  Flintshire  commences  with  beds  of  shale  and  sand- 
stone. The  coal  is  of  various  thickness,  from  f  to  5  yards,  and  consists  of  the  common, 
cannel,  and  peacock  varieties. — Phillips  and  Conybcarc. 


344 


CO^VL. 


Cumberland. — This  coal-field  extends  as  a  narrow  crescent  from  Whitehaven  to  near 
Hesket  Newmarket : — around  Whitehaven  and  at  Workington  the  coal  is  worked  extensively. 
At  the  latter  place,  a  few  years  since,  a  very  valuable  colliery  was  destroyed  by  the  bursting 
ui  of  the  sea. 

There  are  three  workable  seams  in  the  Cumberland  coal-field  in  the  neighborhood  of 
the  three  undermentioned  towns,  and  these  are  known  in  each  place  by  the  names  given  : — 


Whitehaven.                                AVovkington. 

Maryport. 

Bannock  band. 
Maiu  band. 

Six-quarter  coal  or  Low- 
bottom  seam. 

lloorbunks. 
Main  seam. 
Hamilton  seam. 

Ten  quaiters. 

Cannt'l  and  metal  scams,  (divided 

with    shale   from   2   feet   to  5 

fatlioms  thick.) 

Northumberland  and  Durham. — The  total  thickness  of  the  coal  measures  of  this  dis- 
trict is  about  1,600  feet.  The  number  of  distinct  layers  or  beds,  as  usually  noted  by  the 
miners,  about  600.  The  total  thickness  of  the  beds  of  coal  rarely  exceeds — does  not,  on 
the  average,  equal — 60  feet.  No  bed  of  coal  is  of  greater  thickness,  even  for  a  short  dis- 
tance, than  6  or  7  feet ;  several  are  so  thin  as  to  be  of  no  value  at  present.  The  total 
thickness  of  "  workable  coal,"  supposing  all  the  beds  to  be  found  in  a  given  tract,  is  not  to 
be  estimated  at  above  20  or  30  feet.  The  most  part  of  the  coal  in  this  great  district  is  of 
the  coking  quality,  but,,  in  this  respect,  there  is  much  variation.  The  best  coke  for  locomo- 
tive engines  is  now  made  from  the  lower  coals  in  the  Auckland  district  of  Durham,  and  the 
Sliotley  Bridge  district  of  Northumberland.  The  best  "  steam  coal  "  is  obtained  from  the 
north  side  of  the  Tyne  and  the  Blyth  district.  The  best  "  house  coal  "  still  comes  from  the 
remains  of  the  "  High  chain  "  on  the  Tyne,  and  from  the  "  Hutton  seam"  on  the  Wear; 
but  the  collieries  north  of  the  Tees  have  acquired  a  high  reputation. 

As  a  general  view  of  the  groups  of  strata  the  following  summaries  may  suffice. — {Foster 
and  Buddie.) 

Upper  groups  of  coal  measures,  including  chiefly  thin  seams  of  small  value  (8  or  more) 
in  a  vast  mass  of  sandstone  and  shales,  with  some  iron-stone.  At  the  base  is  a  mussel 
band  ;  we  estimate  this  at  900  feet. 


On  the  Tyne : — 


Ft. 

In. 

Illr/h  main  coal    - 

6 

0 

Unknown 

Strata  and  thin  coals    - 

GO 

0 

Five-quarter  coal  - 

Metal  coal    - 

1 

6 

Strata  and  thin  coals    - 

30 

0 

Stone  coal    -         -         - 

3 

0 

Strata 

83 

0 

Yard  coal     -         -         - 

3 

0 

Main  coal 

Strata 

- 

90 

0 

Bensham  seam 

. 

3 

0 

Mandlin  seam 

Strata  with  several  variable 

beds  and  some  lavers 

of 

mussels     - 

- 

150 

0 

Low   main   or   Hutton 

Loxo  main  coal 

- 

6 

0 

seam 

Strata 

- 

200 

0 

llervci/s  seam 

- 

3 

0 

Beaumont  seam     - 

Strata 

- 

300 

0 

Brockicell  seam     • 

- 

3 

0 

Brockwell  seam     - 

Strata  above  millstone  gi 

it   - 

200 

0 

On  the  Wear  and  Tyne  :- 
Ft.  In. 


Ft.  In. 


3     9  to  6     9 


5     6  to  6     0 


4     C  to  6     0 


4     6  to  6     6 


3     0  to  6     0 

3     0  to  6     0 
— PJdllips. 

The  seams  which  are  principally  worked  in  this  district  are  the  high  main,  five-quarter 
main,  Bensham  seam,  Hutton  seam,  Beaumont  seam,  low  five-quarter,  three-quarter  seam, 
Brockwell  and  stone  coals.  These  seams  are  known  by  other  names,  each  district  usually 
adopting  its  own  peculiar  term  to  designate  the  workable  seams.  Thus  the  Bensham  seam 
of  the  Tyne  is  known  as  the  Mandlin  scam  of  the  Wear.  The  Beaumont  or  Hervcy  scam  is 
the  Townley  seam  of  the  Townley  colliery  and  the  main  coal  of  Wylam  colliery.  At  Ilet- 
ton  the  high  main  seam  of  the  Cramlington  district  separates  into  two,  and  is  called  the 
three-quarter  seam  at  Pontoss ;  where  it  unites  again  it  is  known  as  the  Shieldrow  seam. 
The  Cramlington  gray  seam  is  the  metal-coat  seam  and  stone  coal  seam  of  Sherrilf  Hill, 
where  it  is  divided  ;  while  it  unites  at  Hetton  and  forms  the  five-quarter  seam  of  that  and 
the  Auckland  district.  The  Cramlington  yard  seam'  becomes  the  main  coal  seam  at  Hetton, 
Haswell,  and  some  other  localities,  the  Brass  Thill  at  Pontsss,  and  the  main  coal  in  Auck- 
land. Again  the  Cramlington  five-quarter  seam  di\ides  and  forms  the  .=ix-quarter,  and  the 
five-quarter  at  Shcrriff  Hill  the  Br.a.ss  Thill  seam  at  Pittington  ;  they  again  unite  and  form 


COAL. 


345 


the  Hutton  seam  at  Pontoss  colliery,  and  so  with  regard  to  a  few  others. — Mineral  Sta- 
tistics. 

Scotland. — "  A  memoir  on  the  Mid-Lothian  and  East  Lothian  coal-fields,"  by  David 
Milne,  gives  the  most  exact  account  of  the  carboniferous  system  of  Scotland. 

There  are  three  principal  coal  basins  in  Scotland :  1.  that  of  Ayrshire  ;  2.  that  of 
Clydesdale  ;  and  3.  that  of  the  valley  of  the  Forth,  which  runs  into  the  second  in  the  line 
of  the  Union  canal.  If  two  lines  be  drawn,  one  from  Saint  Andrev>"s  on  the  north-east 
coast,  to  Kilpatrick  on  the  Clyde,  and  another  from  Aberlady,  in  Haddingtonshire,  to  a 
point  a  few  miles  south  of  Kirkoswald  in  Ayrshire,  they  will  include  between  them  the 
whole  space  where  pitcoal  has  been  discovered  and  worked  in  Scotland. 

According  to  Mr.  Farey,  there  are  337  principal  alterations  of  strata  between  the  surface 
in  the  town  of  Fisherrow,  on  the  banks  of  the  Frith  of  Forth,  (where  the  highest  of  these 
strata  occur,)  and  tlie  commencement  of  the  basaltic  rocks,  forming  the  general  floor  and 
border  of  tin's  important  coal-field.  These  strata  lie  internally  in  the  form  of  a  lengthened 
basin  or  trough,  and  consist  of  sandstone,  shale,  coal,  limestone,  ironstone,  &c.  Sixty-two 
seams  of  coal,  counting  the  double  seams  as  one ;  7  limestone ;  72  assemblages  of  stone 
and  other  strata  ;  in  all  5,000  feet  in  thickness. 

Professor  Phillips  remarks  of  this  district,  "  On  the  whole,  allowing  for  waste,  imattain- 
able  portions,  and  other  circumstances,  this  one  district  may  be  admitted  as  likely  to  yield 
to  the  miner  for  actual  use  2,250  millions  of  tons  of  coal."  The  coal  is  partly  "splint," 
partly  "  rough  "  or  "  cherry,"  partly  of  the  "  cannel  "  or  "  parrot "  variety  ;  the  first  con- 
taining most  oxygen,  the  last,  most  hydrogen  and  nitrogen,  and  the  least  carbon.  See 
Boghead  Coal. 

Ireland. — The  coal-fields  of  Ireland,  if  we  include  in  this  term  the  millstone  grit,  occu- 
py large  tracts  of  land  in  that  country,  and  are  upon  the  whole  analogous,  in  general  mineral 
character  and  organic  contents,  to  those  of  England.  The  same  absence  of  limestone,  the 
same  kind  of  succession  of  sandstones  and  shales  is  remarked  in  them.  Anthracite  or 
stone-coal  like  that  of  South  Wales  abounds  in  the  Leinster  and  Munster  districts ;  bitumi- 
nous coal  occurs  in  Connaught  and  Ulster.  In  Ulster  the  principal  collieries  are  at  Coal 
Island  and  Dungannon.  The  Munster  coal  district  is  stated  by  Mr.  Griffith  to  be  of  greater 
extent  than  any  English  coal-field,  but  it  is  much  less  productive.  At  Ballycastlc  the  coal 
is  found  in  connection  with  basalt. — Phillips. 

Such  is  a  general  and  rapid  sketch  of  the  distribution  of  fossil  fuel  over  the  Islands  of 
the  United  Kingdom.  The  importance  of  a  correct  knowledge  of  the  distribution  of  coal 
in  other  parts  of  the  world,  especially  to  a  commercial  people  whose  steamers  now  trav- 
erse every  sea,  has  led  to  tlie  compilation,  from  the  most  reliable  sources,  of  the  following 
account : 

Between  the  Arctic  Circle  and  the  Tropic  of  Cancer  repose  all  the  principal  carboniferous 
formations  of  our  planet.  Some  detached  coal  deposits,  it  is  true,  exist  above  and  below 
these  limits,  but  they  appear,  so  far  as  we  know,  to  be  of  limited  extent.  Many  of  these 
southern  coal-fields  are  of  doubtful  geological  age  ;  a  few  are  supposed  to  approximate  to 
the  class  of  true  coals,  as  they  are  commonly  styled,  others  are  decidedly  of  the  brown  coal 
and  tertiary  period,  while  the  remainder  belong  to  various  intermediate  ages,  or  possess 
peculiarities  which  render  them  of  doubtful  character. 

Southward  of  the  Tropic  of  Cancer  the  existence  of  coal  corresponding  with  the  European 
and  American  hard  coal  is  somewhat  uncertain.  There  seems  to  be  little  coal  on  the  South 
American  continent.  The  discovery  said  to  be  made  at  Ano  Paser  needs  confirmation,  and 
of  that  in  the  province  of  Santa  Catharina  in  Brazil  we  know  little.  On  the  African  conti- 
nent we  have  had  vague  accounts  of  coal  in  Ethiopia,  and  at  Mozambique,  also  at  Madagas- 
car, and  quite  recently  we  have  had  intelligence  of  large  quantities  of  coal  in  the  newly- 
ceded  territory  above  Port  Natal,  on  the  eastern  side  of  Africa,  but  we  believe  no  geologist 
has  examined  these  sites.  In  the  Chinese  and  Burmese  empires  brown  coal  only  appeal's  to 
approach  the  Tropic,  but  true  coal  seems  to  exist  in  the  .northern  provinces.  Southward  of 
the  Asiatic  continent  we  are  uncertain  of  the  exact  character  of  the  coal  deposits,  such  as 
occur  at  Sumatra,  Java,  and  Borneo,  and  neighboring  islands.  Coal,  however,  exists  in 
these  islands,  and  is  of  a  fair  workable  quality. 

In  New  South  Wales  the  great  coal  range  on  the  eastern  margin  of  that  continent  has 
sometimes  been  described  as  resembling  the  Newcastle  coal  in  England,  and  .sometimes  it  is 
described  as  of  more  ancient  date.  Tliis  coal  dilfers  essentially  from  that  of  any  known 
European  formation,  but  hears  a  strong  resemblance  to  the  Burdwan  coal  of  India. 

We  have  not  yet  arrived  at  the  period  when  we  could  pronounce  with  any  approach  to 
certainty  on  the  actual  innnbcr  of  coal  basins  in  the  world  ;  the  total  nmnbcr  must,  how- 
ever, amount  at  least  to  from  250  to  300  principal  coal-fields,  and  many  of  these  are  subdi- 
vided by  the  distm-bed  position  of  the  strata  into  subordinate  basins. 

The  basins  or  coal  districts  are,  however,  grouped  into  a  comparatively  small  number  of 
districts,  and  even  many  of  these  are  little  known  and  not  at  all  measured.     The  greater 


346  COAL. 

number  occur  in  Western  Europe  and  Eastern  North  America,  while  Central  and  Southern 
Africa,  South  America,  and  a  large  part  of  Asia  are  almost  without  any  trace  of  true  car- 
boniferous rocks.  The  remarks,  therefore,  that  will  follow  chiefly  refer  to  our  own  and 
adjacent  countries,  or  of  the  United  States  and  British  North  America. 

The  principal  coal-fields  of  Europe,  apart  from  the  British  Islands,  are  those  of  Belgium, 
I'rance,  Spain,  (in  the  Asturias,)  Germany,  (on  the  Ruhr  and  Saare,)  Bohemia,  Silesia,  and 
Kussia,  (on  the  Donetz.) 

Bklgium. — The  Belgian  coal-field  is  the  most  important,  and  occupies  two  districts,  that 
of  Liege  and  that  of  Hainault,  the  former  containing  100,000,  and  the  latter  200,000  acres. 
In  each,  the  number  of  coal  seams  is  very  considerable,  but  the  beds  arc  thin  and  so  much 
disturbed  as  to  require  special  modes  of  working.  The  quality  of  coal  is  very  various,  in- 
cluding one  peculiar  kind,  the  Flenu  coal,  unlike  any  found  in  Great  Britain,  except  at 
Swansea.  It  burns  rapidly  with  much  flume  and  smoke,  not  giving  out  an  intense  heat,  and 
having  a  somewhat  disagreeable  smell.  There  are  nearly  fifty  scams  of  this  coal  in  the 
Mons  district.     No  iron  has  been  found  with  the  coal  of  Belgium. 

Mr.  Dunn,  H.  M.  Inspector  of  Collieries,  has  reported  on  the  coal  of  Belgium :  and  first 
quoting  a  report  which  announces  that  the  mines  would  be  exhausted  in  twenty  years,  says : 
"  This  announcement  comes  with  appalling  force  upon  the  numerous  joint-stock  companies. 
'  *  *  *  According  to  the  report  of  il.  Briavionne,  Belgium  is  traversing  towards  a  momen- 
tous crisis ;  and  I  am  much  inclined  to  confirm  the  writer's  opinion  that,  according  to  the 
present  plan  of  carrying  on  the  collieries,  notwithstanding  the  high  price  received  for  the 
coals,  yet  that  coal  will  not  be  found  workable  to  profit  below  the  depth  of  250  or  2G0 
fathoms,  inasmuch  as  the  deeper  they  go  the  more  destructive  and  unmanageable  will  be 
the  effects  of  the  pressure." — Tlie  Government  Miyiing-Engineer' s  Report. 

Belgium  is  traversed,  in  a  direction  from  nearly  west -south-west  to  east-north-east,  by  a 
large  zone  of  bituminous  coal  formation.  The  entire  region  is  generally  described  under 
two  principal  divisions  : — 

\.  The  western  or  Hainault  division,  comprising 

a.  The  two  basins  known  as  Levant  and  Couchant  of  Mons. 
That  of  Charleroi. 

b.  The  basin  of  Namur. 
2.  The  eastern  or  Liege  division. 

France. — The  most  important  coal-fields  of  France  are  those  of  the  basin  of  Loire,  and 
those  of  St.  Etienne,  which  are  the  best  known  and  largest,  comprising  about  50,000  acres. 
In  this  basin  are  eighteen  beds  of  bituminous  coal,  and  in  the  immediate  neighborhood 
several  smaller  basins  containing  anthracite.  Other  valuable  localities  are  in  Alsace,  several 
in  Burgundy  worked  by  very  deep  pits,  and  of  considerable  extent ;  some  in  Auvergne  with 
coal  of  various  qualities  ;  some  in  Languedoc  and  Provence  with  good  coal ;  others  at  Ar- 
veyron ;  others  at  Limosin  ;  and  some  in  Normandy.  Besides  these,  thefe  are  several 
others  of  smaller  dimensions  and  less  extent,  whose  resources  have  not  been  developed. 
The  total  area  of  coal  in  France  has  not  been  ascertained,  but  it  is  probably  not  less  than 
2,000  square  miles.  The  annual  production  now  exceeds  4,000,000  tons.  But  the  coal  of 
France  is  of  an  inferior  description,  and,  therefore,  when  good  and  strong  coals  are  required, 
the  supply  is  obtained  from  the  English  coal-fields.  The  mineral  combustibles  of  France 
are  divided  by  the  government  engineers  into 

Anthracite,  not  yielding  coke. 
Hard  coal,  short  flame. 
Forging  or  gaseous  coal. 


Gaseous  coal,  long  flame. 
Small  coal,  long  flame. 
Lignite,  Stipite,  &c. 


The  total  of  indigenous  fuel  extracted,  according  to  the  State  returns,  is  47,222,743 
metrical  quintals  of  10'14(J5  to  the  English  ton. 

The  geological  phenomena  attendant  upon  the  coal  formations  in  France  are,  that  in 
some  places  we  have  the  coals  resting  on  the  granite  and  schists,  and  in  others  on  the  Silu- 
rian rocks. 

Taylor  gives  the  details  of  eighty-eight  coal,  anthracite,  and  lignite  basins  in  France. 
In  1852  only  nine  of  these  produced  coal  to  any  extent.  The  total  produce  of  all  the  coal- 
fields being  4,816,-355  tons,  valued  at  £1,870,072  sterling. 

Germany. — The  Germanic  Union — the  Zollverein — embraces  the  following  principal 
coal-beds  ■ — 

I  Saxony. 
German  States,    i  Bavaria. 


Prussian  States. 


(  Duchy  of  Flesse. 

in  Westphalia. 


!La  Ruhr,  ii 
Sile.sia. 
Saarbriick, 


and  provinces  of  the  Bas  Rhin. 


COAL.  347 

The  true  coal  of  Prussian  Silesia  stretches  for  a  distance  of  seventeen  leagues.  The 
most  recent  information  we  have  been  able  to  obtain  as  to  its  production,  would  appear  to 
give  above  850,000  English  tons.  The  coal-fields  of  Westphalia  were  described  by  Sedg- 
wick and  Murchison  in  1840.  The  productive  coal-beds  are  on  the  right  bank  of  the  Rhine, 
and  possess  many  features  in  common  with  the  English  coal-fields.  Bituminous  wood,  and 
lignite  or  brown  coal,  occur  extensively  in  some  districts.  The  coal  basin  of  Saarbruck,  a 
Rhenish  province  belonging  to  Prussia,  has  thus  been  described  by  Humboldt,  chiefly  from 
a  communication  received  from  M.  Von  Dechen  : — 

"  The  depth  of  the  coal  measures  at  Mont  St.  Gillcs,  Liege,  I  have  estimated  at  3,fi."iO 
feet  below  the  surface,  and  3,250  feet  below  the  sea  level.  The  coal  basin  at  Mons  lies 
fully  1,730  feet  deeper.  These  depressions,  however,  are  trifling  when  compared  with  that 
of  the  coal  strata  of  the  Saar  rivers,  (Saarbriick.)  After  repeated  trials  I  have  found  that 
the  lowest  coal  strata  known  in  the  county  of  Duttweiler,  near  Bettingen,  north-eastward 
from  Saar-louis,  dip  19,406  feet,  and  20,650  under  the  level  of  the  sea." 

The  coal  of  the  valkij  of  the  Glane  is  bituminous,  and  of  good  quality ;  it  is  procur- 
able at  a  depth  of  112  feet,  and  the  seam  is  about  two  feet  in  thickness :  about  50,0U0  tons 
annually  are  produced  from  this  valley.  Coal  is  found  in  Wurtemburg,  but  not  much 
worked.  In  Saxony  arc  extensive  mines  of  bituminous  coal ;  at  Schonfield,  near  Zivickau, 
the  coal  alternates  with  porphyry.  Near  Dresden  a  bituminous  coal  is  also  worked,  and  the 
coke  manufactured  from  it  is  used  in  the  metallurgical  works  at  Freiburg. 

The  Hessian  States  produce  little  beyond  lignite.  In  Hesse  Cassel  some  bituminous 
coal  is  worked,  but  to  a  very  inconsiderable  extent. 

In  the  Thurmgcrwald  or  Thuringian  forest  some  coal  is  produced. 
Hungary  and  other  countries  in  the  east  of  Europe  contain  true  coal  measures  of 
the  carboniferous  period  ;  but  the  resources  of  these  districts  are  not  at  present  developed. 
On  the  banks  of  the  Donetz,  in  Russia,  coal  is  worked  to  some  extent,  and  is  of  excellent 
quality. 

Austria. — Coal  occurs  in  Styria,  Carinthia,  Dalmatia,  the  Tyrol,  Moravia,  Lombardy, 
and  Venice  ;  but  700,000  tons  appear  to  be  the  maximum  annual  produce  of  the  empire. 
The  basin  of  Vienna,  in  Lower  Austria,  produces  several  varieties  of  coal,  which  belong  to 
the  brown  coal  of  the  tertiary  period. 

Bohemia. — In  this  kingdom  coals  are  abundant ;  one  coal-field  occupies  a  length  of  15 
leagues,  and  a  breadth  of  from  4  to  5  leagues.  Between  300,000  and  400,000  tons  are 
produced  annually. 

Sweden. — Anthracite  is  found  in  small  quantities  at  Dannemora  ;  and  bituminous  coul 
is  worked  at  Helsingborg,  at  the  entrance  of  the  Baltic. 

Dknmark. — The  island  of  Bornholm  and  some  other  islands  belonging  to  Denmark  pro- 
duce coal,  but  it  would  appear  to  belong  to  the  Bovey  coal  variety. 

RcssiA. — The  Donetz  coal-field  is  the  most  important.  In  that  extensive  district  many 
good  seams,  according  to  Sir  R.  I.  Murchison,  of  both  bituminous  and  anthracite  coal 
exist. 

Tdrket. — Coal  is  found  bordering  on  the  Carpathian  mountains,  in  Servia,  Roumelia, 
and  Bulgaria. 

The  coal  of  Heraelia,  on  the  south  coast  of  the  Black  Sea,  in  Anatolia,  has  been,  since 
the  Crimean  war,  exciting  much  attention. 

Spain. — Spain  contains  a  large  quantity  of  coal,  both  bituminous  and  anthracite.  The 
richest  beds  are  in  Asturias,  and  the  measures  are  so  broken  and  altered  as  to  be  worked 
by  almost  vertical  shafts  through  the  beds  themselves.  In  one  place  upwards  of  1 1  distinct 
seams  have  been  worked,  the  thickest  of  which  is  nearly  14  feet.  The  exact  area  is  not 
known,  but  it  has  been  estimated  by  a  French  engineer  that  about  12,000,000  of  tons  might 
be  readily  extracted  from  one  property,  without  toucliing  the  portion  existing  at  great 
depths.  In  several  parts  of  the  province  the  coal  is  now  worked,  and  the  measures  seem 
to  resemble  those  of  the  coal  districts  generally.  The  whole  coal  area  is  said  to  be  the 
largest  in  Europe,  presenting  upwards  of  100  workable  seams,  varying  from  3  to  12  feet  in 
thickness. 

The  Asturias  Mining  Company  are  working  many  mines  in  this  region,  and  they  are  said 
to  produce  400,000  tons  annually,  or  to  be  capable  of  doing  so.     In  Catalonia  and  in  the 
Basque  provinces  of  Biscay  there  are  found  anthracite  and  bituminous  coals. 
In  the  Balearic  islands  also  coal  exists. 

Portugal. — Beds  of  lignite  and  some  anthracite  are  known  to  exist,  but  the  produc- 
tion of  either  is  small. 

Italy. — The  principal  coal  mines  of  Italy  are  in  Savoy  and  near  Genoa.  In  the  Apen- 
nines some  coal  is  found,  and  in  the  valley  of  the  Po  are  large  deposits  of  good  lignite  and 
a  small  quantity  of  good  coal  is  worked  in  Sardinia. 

North  America. — There  are  in  North  America  four  principal  coal  areas,  compared  with 
which  the  richest  deposits  of  other  countries  are  comparatively  insignificant.  These  are  the 
great  central  coal-fields  o?  the  Alleghauies ;  the  coal-fields  of  Illinois,  and  the  basin  of  the 


348  COAL. 

Ohio  ;  that  of  the  basin  of  the  Missouri ;  and  those  of  Nova  Scotia,  New  Brunswick,  and 
Cape  Breton.  Besides,  there  are  many  smaller  coal  areas  which,  in  other  countries,  might 
well  take  rank  as  of  vast  national  importance,  and  which  even  in  North  America  will  one 
day  contribut-e  greatly  to  the  riches  of  vaiious  States. 

The  Alleghany  or  Appalachian  coal-field  measures  V50  miles  in  length,  with  a  mean 
breadth  of  85  miles,  and  traverses  eight  of  the  principal  States  in  the  American  Union. 
Its  whole  area  is  estimated  at  not  less  than  65,000  square  miles,  or  upwards  of  40,000 
square  acres.     The  coal  is  bituminous,  and  used  for  gas. 

Coal  has  been  found  in  Louisiana,  on  the  Iberville  rivers,  and  on  the  shores  of  Lake 
Bistineau  :  it  is  also  reported  as  having  been  found  at  Lake  Borgne — but  this  is  probably  a 
lignite.  In  Kentucky  both  bituminous  and  cannel  coal  are  worked  in  seams  about  3  or  -t 
feet  thick,  the  cannel  being  sometimes  associated  with  the  bituminous  coal  as  a  portion  of 
the  same  seam  •,  and  there  are  in  addition  valuable  bands  of  iron  ore,  {the  argiUactous  car- 
bonate.) The  coal-field  of  Kentucky  extends  over  about  9,000  square  miles.  In  Western 
Virginia  there  are  several  coal-fields  of  vaiiable  thickness :  one,  9i  feet ;  two  others  of  5, 
and  others  of  3  or  4  feet.  On  the  whole  there  seem  to  be  at  least  40  feet  of  coal  dis- 
tributed in  13  seams.  In  the  Ohio  district  the  whole  coal-field  afibrds  on  an  average  at 
least  6  feet  of  coal.  The  Marykmd  district  is  less  extensive,  but  is  remaikable  as  contain- 
ing the  best  and  most  useful  coal,  which  is  worked  now  to  some  extent  at  Frcstbury.  There 
appear  to  be  about  30  feet  of  good  coal  in  4  seams,  besides  many  others  of  less  importance. 
The  quality  is  intermediate  between  bituminous  and  anthracite,  and  is  considered  well 
adapted  for  iron-making.  Lastly,  in  Pennsylvania  there  are  generally  from  two  to  five 
workable  beds,  yielding  on  an  average  10  feet  of  workable  coal,  and  amongst  them  is  one 
bed  traceable  for  no  less  than  450  miles,  consisting  of  bituminous  coal,  its  thickness  being 
from  12  to  14  feet  on  the  south-eastern  border,  but  gradually  diminishing  to  5  or  6  feet. 
Besides  the  bituminous  coal  there  are  in  Pennsylvania  the  largest  anthracite  deposits  in  the 
States,  occupying  as  much  as  250,000  acres,  and  divided  into  three  principal  districts. 

The  Illinois  coal-field,  in  the  plain  of  the  Mississippi,  is  only  second  in  importance  to 
the  vast  area  already  described.  There  are  four  principal  divisions  traceable,  of  ■which  the 
first,  or  Indian  district,  contains  several  scams  of  bituminous  coal,  distributed  over  an  area 
of  nearly  8,000  square  miles.  It  is  of  excellent  quality  for  many  purposes  ;  one  kind  burn- 
ing with  much  light  and  very  freely,  approaching  cannel  coal  in  some  of  its  properties ; 
other  kinds  consist  of  caking  or  splint  coal.  In  addition  to  the  Indian  coal-field  there  ap- 
pears to  be  as  much  as  48,000  square  miles  of  coal  area  in  other  divisions  of  the  Illinois 
district,  although  these  are  less  known  and  not  at  present  much  worked.  30,000  are  in  the 
State  of  Illinois,  which  supplies  coal  of  excellent  quality,  and  with  great  facilitj^.  The  coal 
is  generally  bituminous. 

'    The  third  great  coal  area  of  the  United  States  is  that  of  the  Missouri,  which  is  little 
known  at  present,  although  certainly  of  great  im]>ortance. 

Taylor  states  that  at  least  one-eighth  of  the  State  of  Missouri  is  overlaid  by  coal  meas- 
ures. G,000  square  miles  are  assigned  to  the  coal-fields  of  Missouri.  Bituminous  coal  is 
stated  to  have  been  found  in  the  Arkansas  valley,  and  brown  coal  and  lignite  in  abundance 
in  the  Upper  Missouri  valley. 

British  America  contains  coal  in  the  provinces  of  New  Brunswick  and  Nova  Scotia. 
The  former  presents  8  coal-fields,  occupying  in  all  no  less  than  8,000  square  miles ;  the 
latter  exhibits  several  very  distinct  localities  where  the  coal  abounds.  The  New  Brunswick 
coal  measures  include  not  only  shales  and  sandstones,  as  is  usual  with  such  deposits,  but 
bands  of  lignite  impregnated  with  various  coj)per  ores,  and  coated  by  green  carbonate  of 
copper.  The  coal  is  generally  in  thin  seams  lying  horizontally.  It  is  chiefly  or  entirely 
bituminous. 

Nov.\  Scotia  possesses  three  coal  regions,  of  which  the  northern  presents  a  total  thick- 
ness of  no  less  than  14,570  feet  of  measures,  having  TO  seams,  whose  aggregate  magnitude 
is  only  44  feet,  the  thickest  beds  being  less  than  4  feet.  The  Pictou  or  central  district  has 
a  thickness  of  7,590  feet  of  strata,  but  the  coal  is  far  more  abundant,  one  seam  measuring 
nearly  30  feet ;  and  part  of  the  coal  being  of  excellent  quality  and  adapted  for  steam  pur- 
poses. The  southern  area  is  of  less  importance.  Besides  the  Nova  Scotia  coal-fields  there 
are  three  others  at  Cape  Breton,  yielding  difterent  kinds  of  coal,  of  which  one,  the  Sydney 
coal,  is  admirably  adapted  for  domestic  purposes.  There  are  here  14  seams  above  3  feet 
thick,  one  being  11,  and  one  9  feet. 

NKWForxDLANn  CoAL-Fira.D. — This  field  is  estimated  at  about  .'"),000  square  miles.  Ac- 
cording to  Mr.  Jukes,  now  Director  of  the  Geological  Survey  in  Ireland,  the  entire  western 
side  of  the  island,  along  a  space  of  35fi  miles  in  breadth,  is  occupied  by  secondary  and  car- 
boniferous rocks.  The  coal  on  the  southwestern  point  of  the  island  has  been  traced  at  inter- 
val.s,  along  a  space  of  1 50  to  200  miles  to  the  north-ea.st. 

Greknland. — Captain  Scoresby  discovered  a  regular  coal  formation  here.  At  Ilasen 
Island,  Bovey  or  brown  coal  has  been  found,  and  also  at  Disco  Island  on  the  western 
coast. 


COAL.  349 

Arctic  Ocean. — At  Byara  Martin's  Island  coal  formations  exist ;  and  at  Melville  Island 
several  varieties  of  coal  have  been  discovered,  much  of  it  being  of  an  anthracitic  or  of  a 
semi-anthracitic  character.  We  learn  that  at  Prince  Regent's  Inlet  indications  of  coal  have 
been  observed. 

Rl'ssian  America. — Beyond  the  icy  cape  and  at  Point  Barrow,  coal  was  observed  on 
the  beach ;  and  it  has  been  found  by  digging  but  a  few  feet  below  the  surface  at  Point 
Franklin. 

Oregon  Territory. — Coal  has  been  discovered  and  worked  in  Wallamette  valley, 
nearly  100  miles  above  Oregon  City ;  and  anthracite  has  been  observed  by  Sir  George 
Simpson  about  30  miles  up  one  of  the  tributaries  of  the  Columbia  River. 

California. — Colonel  Fremont  states  that  a  coal  formation  exists  in  Upper  California, 
Xorth  lat.  4H',  and  West  long.  lOTi'.  "The  position  of  this  coal  formation  is  in  the 
centre  of  the  Rocky  Mountain  chain,  and  its  elevation  is  6,820  feet  above  the  level  of  the 
sea.  In  sonie  of  the  coal  seams  the  coal  did  not  appear  to  be  perfectly  mineralized,  and  in 
others  it  was  compact  and  remarkably  lustrous." — Fremont's  Report,  1843. 

In  1847  a  coal  mine  was  discovered  near  San  Luis  Obisco,  Xorth  lat.  35'.  There  are 
three  coal  mines  within  300  miles  of  Monterey. 

Mexico. — On  Salado  River  coal  is  worked  by  an  American  company.  A  coal  formation 
50  miles  in  breadth  crosses  the  Rio  Grande  from  Texas  into  Mexico  at  Loredo,  and  on  the 
Mexican  shore,  within  200  yards  of  the  Rio  Grande,  a  remarkable  fine  vein  of  coal  8  feet 
thick  occurs. 

Texas. — Coal  is  known  to  exist  in  Texas,  though  the  country  has  not  been  geologically 
examined.  The  "  Trinity  Coal  and  Mining  Company  "  was  incorporated  by  the  Texan  Con- 
gress in  1840,  who  worked  both  anthracite  and  a  semi-bituminous  coal.  Kennedy,  in  his 
work,  "  Texa^i,  its  Geoyrapfuj,  d'c,"  says,  "  Coal,  both  anthracite  and  bituminous,  abounds 
from  the  Trinity  River  to  the  Rio  Grande." 

South  America. — In  the  republic  of  New  Granada,  especially  at  Santa  Fe  de  Bogota, 
coal  occurs ;  also  in  the  island  of  Santa  Clara,  and  brown  coal  in  the  province  of  Panama. 

Yesezuela  is  said  to  contain  coal,  but  whether  brown  or  bituminous  coal  does  not 
appear  certain. 

Peru  appears  to  possess  some  coal,  but  a  fossil  charcoal  of  considerable  value  is  more 
abundant. 

Chili. — The  coal  of  this  district  has  been  examined  by  many  American  engineers,  and 
by  Captains  Fitzroy  and  Beechy  and  Mr.  Darwin.  In  1844  upward  of  20  coal  mines  were 
open  in  the  neighborhood  of  Conception.  At  Tulcahnano  a  new  seam  of  4.V  feet  was 
proved.  The  coal  is  described  by  W.  R.  Johnson  as  "  in  external  appearance  nearly  rela- 
ted to  many  of  the  richest  bituminous  coals  of  America  and  Europe ;"  and  Mr.  Wheel- 
wright, in  his  report  on  the  mines  and  coal  of  Chili,  says,  "  in  fact,  the  whole  southern 
country  is  nothing  but  a  mine  of  coal." 

Brazil  does  not  appear  to  possess  much  coal  of  any  value,  beyond  a  few  lignites. 

The  West  Indian  Islands. — Cuba,  in  the  vicinity  of  Havana,  produces  a  kind  of 
asphaltura  much  resembling  coal,  the  analysis  of  which  gives,  carbon  34-97,  volatile  matter 
63'00,  ashes  2'03.  At  New  Havana  a  similar  combustible  is  found  ;  but  it  contains  71  "84 
of  carbon.  True  coal  does  not  appear  to  have  been  found  in  Jamaica.  Sir  H.  dc  la  Beche, 
Trans.  Geological  Socieli/  of  London,  describes  three  or  four  thin  seams  of  coal  imbedded 
in  shale  near  the  north-eastern  extremity  of  the  island. 

Barbadoes. — Bitumen  is  found  plentifully ;  and,  on  Grove  Plantation  estate,  a  good 
coal  is  stated  to  have  been  found. 

Trinidad. — The  pitch  lake  of  this  island  is  well  known.  Near  it,  and,  it  is  believed, 
extending  under  it,  a  true  coal  of  superior  quality  is  worked. 

For  a  very  satisfactory  description  of  the  coal-field  of  South  StafFordshire,  the  reader  is 
referred  to  a  memoir  "  On  the  Geology  of  the  South  Staffordshire  Coal-field,"  by  J.  Beete 
Jukes,  published  in  the  "  Records  of  the  School  of  Mines." 

It  is  not  possible  in  the  present  work  to  enter  into  any  further  description  of  the  coal- 
fields of  this  country.  In  the  selections  which  have  been  made,  striking  types  have  been 
chosen,  which  are  sufficiently  characteristic  to  serve  the  purposes  of  general  illustration. 
There  are  many  variations  from  tlie  conditions  which  have  been  described,  but  these  arc 
due  to  disturbances  which  have  taken  place  either  since  the  formation  of  the  coal,  or  during 
tiie  period  of  the  actual  deposition  of  the  coal. 

That  coal  is  derived  from  tlie  vegetable  kingdom,  no  longer  admits  of  a  doubt ;  but  the 
class  of  plants  to  which  more  especially  we  are  to  look  for  the  origin  of  coal,  is  still  a  mat- 
ter of  mucli  uncertainty ;  and  the  conditions  under  which  the  change  is  brought  about  arc 
very  imperfectly  understood,  and  indeed  by  many  geologists  entirely  misconceived.  The 
idea  generally  entertained  is,  that — already  described  in  part — which  supposes  a  natural 
basin  in  wliich  vegetable  matter  is  deposited,  the  layers,  according  to  circumstances,  vary- 
ing in  thickness,  which  become  covered  with  nmd  or  sand,  and  were  thus  entombed ;  the 
decomposition  and  disintegration  breaking  up  the  vegetable  structure,  goes  on  for  ages. 


350  GOAL. 

Microscopic  observers  assure  us  that  they  are  enabled  to  detect  ligneous  structure  in  the 
bituminous  coal.  Mr.  Queckct  has  given  a  great  number  of  drawings  in  proof  of  this,  and 
he  refers  the  coal  to  the  icoody  matter  of  an  extinct  class  of  the  Conifera.  Botanists  of 
eminence,  however,  assure  us  that  there  is  no  evidence  of  ligneous  structure  in  any  of  the 
examples  brought  forward  in  proof  of  that  hypothesis. 

Sir  Charles  Lyell,  in  his  excellent  Manual  of  Elementary  Geology,  enters  largely  and 
with  his  usual  lucid  manner  into  the  consideration  of  the  carboniferous  plants.  There  can 
be  no  doubt  of  the  existence  of  the  remarkable  flora  described  by  him  during  the  period 
wlien  our  beds  of  fossil  fuel  were  forming.  Referring  to  Sir  William  Logan  as  his  author- 
ity. Sir  Charles  says :  "  It  was  observed,  that  while  in  the  overlying  shales  or  '  roof  of  the 
coal,  ferns  and  trunks  of  trees  abound,  without  any  stigmaricB,  and  are  flattened  and  com- 
pressed, those  singular  plants  of  the  underclay  (the  stigmariai)  very  often  retain  their  natu- 
ral forms  of  branching  freely,  sending  out  their  slender  leaf-like  rootlets,  formerly  thought 
to  be  leaves,  through  the  mud  in  all  directions."  This  plant  is  singularly  indicative  of  the 
class  of  plants  from  which  coal  has  been  derived. 

M.  Adolph  Brongniart  states  that  the  number  of  species  of  carboniferous  plants  amounts 
to  about  500.  Lindley  informs  us  that  no  less  than  250  ferns  have  been  obtained  from  the 
coal  strata.  Forty  species  of  fossil  plants  of  the  coal  period  have  been  referred  to  the 
Lepidodendronx.  These,  with  E(jidsetaccw,  Colamites,  Asterophyllites,  Sic/illaria,  of  which 
about  thirty-five  species  are  known  with  their  roots,  Stigmariw  and  Conifera,  make  up  the 
remarkable  flora  which  have  been  preserved  to  us  in  our  coal  series. 

Trees  and  humbler  plants  in  great  variety  arc  found  in  the  carboniferous  sandstones  and 
shales,  and  in  the  coal  itself,  but  it  docs  not  appear  that  we  have  any  one  evidence  of  the 
actual  conversion  of  the  woody  fibre  of  these  plants  into  coal ;  that  is,  there  is  no  evidence 
of  the  direct  conversion  of  wood  into  bituminous  coal.  The  trees  are  almost  invariably 
silicified,  or  converted  into  columns  of  sandstone;  the  carbon  which  constituted  the  original 
woody  fibre  being  subxtitnted  by  silica,  or  sometimes  by  carbonate  of  lime,  and  sometimes 
bv  iron.  Sir  Charles  Lyell  has  carefully  examined  the  phenomena,  now  in  progress,  of  the 
great  delta  of  the  Mississippi,  and  ho  perceives  in  them  many  facts  which  fully  explain,  to 
his  mind,  the  progress  of  coal  deposit.  It  cannot,  however,  he  disguised,  that  even  while 
he  refers  the  coal  to  the  supposed  submerged  forests,  he  does  not  venture  to  explain  any 
of  those  changes,  which  he  evidently  believes  depend  upon  some  peculiar  conditions  of 
climate. 

Professor  John  Phillips,  who  has  devoted  much  study  to  this  suliject,  says  :  "  There  is 
no  necessity  to  enlarge  tipon  the  proofs  of  the  origin  of  coal  from  vegetables,  drawn  from 
an  examination  of  its  chemical  constitution,  as  compared  with  the  vegetable  products,  and 
the  composition  of  the  ligncou^parts  of  the  plants,  and  from  the  unanswerable  identity  of 
the  carbonaceous  substa7ice,  into  which  a  vast  multitude  of  fossil  plants  have  been  converted. 
The  chemical  constitution  of  this  carbonaceous  product  of  the  individual  vegetables,  is  ex- 
actly analogous  to  the  chemical  constitution  of  coal ;  and  it  is  cjuite  probable  that  hereafter 
the  reason  of  the  variations  to  which  both  are  suliject,  whether  dependent  on  the  original 
nature  of  the  plant  or  produced  by  unequal  exposure  to  decay  after  inhumation,  or  meta- 
morphic  subseeiuent  operations,  will  be  as  apparent  as  that  of  the  general  argument  arising 
from  a  common  vegetable  origin." — Manual  of  Geology. 

Mr.  Jukes  says :  "  If,  therefore,  we  suppose  wood  (or  vegetable  matter)  buried  under 
accumulations  of  more  or  less  porous  rock,  such  as  sandstone  and  shale,  so  that  it  might  rot 
and  decompose,  and  some  of  its  elements  enter  into  new  combinations,  always  using  up  a 
greater  quantity  of  oxygen  and  nitrogen  than  of  carbon  and  hydrogen,  or  of  oxygen  and 
hydrogen  than  of  carbon,  wc  should  have  the  exact  conditions  for  the  transformation  of 
vegetable  matter  into  coal." — 77/c  Stiident''s  Manual  of  Geology. 

Much  stress  has  been  laid  upon  the  fact  that  we  have  brown  coal  still  retaining  all  the 
unmistakable  characters  of  wood,  and  the  apparent  passage  of  this  into  true  coal. 

Giippert  states  that  the  timlier  in  the  coal  mines  of  Charlottcnbrunn  is  sometimes  con- 
verted into  brown  conl.  The  same  conversion  was  many  years  ago  found  in  an  old  gallery 
of  an  iron  mine  at  Turrach  in  Styria.  A.  Schrotter  explains,  according  to  the  analysis 
m:ide  by  him,  this  conversion,  by  the  separation  of  marsh  gas  and  carbonic  acid  from  the 
ligneous  fibre  of  oak  wood. — Bixehqf. 

The  same  authority  says :  "  This  conversion  of  wood  into  coal  may  take  place  in  four 
different  ways,  namely : 

"  I.  By  the  separation  of  carbonic  acid  and  carburetted  hydrogen. 
'2.  "  "  carbonic  acid  and  water. 

3.  "  "  carburetted  hydrogen  and  water. 

4.  "  "  carbonic  acid,  carburetted  hydrogen  and  water." 

Quoting  the  information  accumulated  by  Bischof  for  the  purpose  of  showing  the  chemi- 
cal changes  which  take  place,  the  following  analyses  are  given  : — 


COAL. 


351 


Carbon. 

Hydrogen. 

Oxygea 

Authority. 

Oak  Wood 

52-53 

5-27 

42-20 

Gay-Lussac 
'  and  Tlienard. 

1  Decayed  Oak  Wood  -        -        -        - 

53-47 

5-16 

4r37 

Liebig. 

1  Fossil  Wood 

57-8 

5-8 

36-4 

Regnault. 

iTurf 

60-1 

6-1 

33-8 

Vaux. 

Lignite 

72-3 

6-3 

22-4 

Regnault. 

Coal  from  Marennen 

76-7 

5-2 

18-1 

Bischof 

Retinite  from  the  brown  coal  mines  of 

Walcliow        -         .         .         .         - 

80-3 

10-7 

9-0 

Schrotter, 

Peat  coal 

80-7 

4-1 

15-2 

Baer. 

Coal 

82-2 

5-5 

12-3 

Bischof. 

Such  is,  in  the  main,  the  evidence  brought  forward  in  support  of  the  view  that  coal  is 
the  result  of  the  decomposition,  upon  the  place  where  it  is  found,  of  woody  fibre.  The 
following  remarks  by  Professor  Henry  Rogers  on  the  structure  of  the  Appalachian  coal  ex- 
hibit some  of  the  difficulties  which  surround  this  view  : — 

"  Each  bed  is  made  up  of  innumerable  very  thin  laminte  of  glossy  coal,  alternating  with 
equally  minute  plates  of  impure  coal,  containing  a  small  admixture  of  finely  divided  earthy 
matter.-  These  subdivisions,  differing  in  their  lustre  and  feature,  are  frequently  of  excessive 
thinness,  the  less  brilliant  leaves  sometimes  not  exceeding  the  thickness  of  a  sheet  of  paper. 
In  many  of  the  purer  coal-beds  these  thin  partings  between  more  lustrous  layers  consist  of 
little  laminse  of  pure  fibrous  charcoal,  in  which  we  may  discover  the  peculiar  texture  of  the 
leaves,  fronds,  and  even  the  bark  of  the  plants  which  supplied  a  part  of  the  vegetable  mat- 
ter of  the  bed.  All  these  ultimate  divisions  of  a  mass  of  coal  will  be  found  to  extend  over 
a  surprisingly  large  surface,  when  we  consider  their  minute  thickness.  Pursuing  any  given 
brilliant  layer,  whose  thickness  may  not  exceed  the  fourth  part  of  an  inch,  we  may  observe 
it  to  extend  over  a  superficial  space  which  is  wholly  incompatible  with  the  idea  that  it  can 
have  been  derived  from  the  flattened  trunk  or  limb  of  any  arborescent  plant,  however  com- 
pressible. When  a  large  block  of  coal  is  thus  minutely  and  carefully  dissected,  it  very  sel- 
dom, if  ever,  gives  the  slightest  evidence  of  having  been  produced  from  the  more  solid 
parts  of  trees,  though  it  may  abound  in  fragments  of  their  fronds  and  deciduous  ex- 
tremities." 

It  is  not  possible,  within  the  space  which  can  be  afforded  to  this  article  in  the  present 
work,  to  examine  further  the  various  views  which  have  been  entertained  by  geologists  and 
chemists  of  the  formation  of  coal.     A  brief  summary  must  now  suffice. 

1.  Coal  is  admitted  upon  all  hands  to  be  of  vegetable  origin. 

2.  Many  refer  coal  to  some  peculiar  changes  which  have  taken  place  in  wood  ;  others  to 
the  formation  and  gradual  subsidence  of  peat  bogs,  {linger.)  Fuel  have  also  been  thought 
by  others  to  supply  the  materials  for  coal-beds. 

3.  By  some  the  coal  is  thought  to  be  found  upon  the  spots  on  which  the  trees  grew  and 
decayed.  By  others  it  is  supposed  that  vast  masses  of  vegetable  matter  were  drifted  into 
lakes  or  deltas,  to  be  there  decomposed. 

4.  Whether  the  plants  grew  on  the  soil — the  under  da>/ — upon  which  the  coal  is  found, 
or  were  drifted  to  it,  there  must  have  been  long  periods  daring  which  nothing  but  vegetable 
matter  was  deposited,  and  then  a  submergence  of  this  land,  and  vast  accumulations  of  mud 
and  sand.  The  number  of  coal  seams  in  some  of  our  coal-fields,  and  the  thicknesses  of  the 
strata  above  them,  have  been  already  given. 

Henry  Rogers  and  others  suppose,  that  the  whole  period  of  the  coal  measures  was 
characterized  by  a  general  slow  subsidence  of  the  coasts  on  which  we  conceive  that  the 
vegetation  of  the  coal  grew ;  that  this  vertical  depression  was,  however,  interrupted  by 
pauses  and  gradual  upward  movements  of  less  frequency  and  duration,  and  that  these  nearly 
statical  conditions  of  the  land,  alternated  with  great  paroxysmal  displacements  of  the  level, 
caused  by  the  mighty  pulsations  of  earthquakes.     (See  F.\ults.) 

The  difficulties  are  mainly  the  facts — 

1.  That  the  evidence  is  not  clear  that  any  thing  like  llgiieons  structure  can  be  detected 
in  coal. 

2.  That  tiie  tvoody  matter  found  in  coal  is  never  converted  into  coal,  although  sometimes 
it  appears  as  if  the  bark  was  so  changed. 

3.  That  tlie  coal  arranges  itself  always  in  exact  obedience  to  the  underlying  surface,  as 
though  a  semi-fluid  mass  had  been  spread  out  on  a  previously  formed  solid  bed. 

4.  The  thinning  out  of  true  coal  to  extreme  tenuity,  as  mentioned  by  Professor  Rogers, 
numerous  examples  of  which  appear  in  this  country. 

5.  The  extreme  difficulty  connected  with  the  subsidence  of  the  surface  of  the  earth  to 
such  a  depth  as  that  to  which  the  lowest  seams  of  coal  extend. 


352 


COAL  BRASSES. 


Wc  do  not  intend  to  answer  any  of  those  difficulties,  but  to  leave  the  question  open  for 
I'lirther  examination,  merely  remarking,  in  conclusion,  that  there  can  be  no  doubt  of  the 
vegetable  origin  of  coal ;  the  only  cjuestion  is,  the  conditions  of  change  by  which  bitu- 
minous coal  has  been  produced  from  vegetable  fibre  ;  and,  that  we  have  not  completed  all 
the  links  in  the  chain  between  brown  coal  and  true  coal. 

In  concluding  this  notice  of  mineral  fuel,  it  may  be  worth  while  to  draw  attention  to  the 
vast  and  overwhelming  importance  of  the  subject,  by  a  reference  both  to  the  absolute  and 
relative  value  of  the  material,  especially  in  the  British  Islands.  It  may  be  stated  as  proba- 
bly within  the  true  limit,  if  we  take  the  annual  produce  of  the  British  coal  mines  at 
66,000,000  tons,  the  value  of  which  is  not  less  than  £16,700,000  sterling  at  the  pits'  mouth, 
which  may  be  estimated  at  the  place  of  consumption,  and  therefore  including  a  certain 
amount  of  transport  cost  necessary  to  render  available  the  raw  material,  at  not  less  than 
£20,000,000.  The  capital  employed  in  the  coal  trade  is  now  estimated  at  £18,500,000. 
Wc  have,  therefore,  the  following  summary,  which  will  not  be  without  interest : 

Value  of  the  coal  annually  raised  in  Great  Britain,  estimated  at 

the  pit  mouth £16,700,000 

Mean  annual  value  at  the  place  of  consumption      -         -         .        20,000,000 

Capital  engaged  in  the  coal  trade 18,500,000 

Mean  annual  value,  at  the  furnace,  of  iron  produced  from  Brit- 
ish coal 14,545,000 

COAL  BRASSES.  Iron  pyrites,  sulpJnde  of  iron,  found  in  the  coal  measures.  .  These 
are  employed  in  Yorkshire  and  on  the  Tyne  in  the  manufacture  of  copperas,  the  proto- 
sulphate  of  iron.  For  this  purpose  they  are  exposed  in  wide-spread  heaps  to  atmospheric 
action  ;  the  result  is  the  conversion  of  the  sulphur  into  sulphuric  acid,  which,  combining 
with  the  iron,  forms  the  sulphate  of  the  jirotoxide  of  iron,  which  is  dissolved  out  and 
recrystallized. 

The  iron  ores  called  Brass,  occurring  in  the  coal  measures  of  South  Wales,  were  par- 
ticularly described  by  E.  Chambers  Nicholson  and  David  S.  Price,  Ph.  D.,  F.C.S.,  at  the 
meeting  of  the  British  Association  at  Glasgow.  Their  remarks  and  analyses  were  as 
follows :  — 

"  There  arc  three  kinds  of  ores  to  which  the  name  brass  is  applied  ;  they  are  considered 
to  be  an  inferior  class  of  ore,  and  are  even  rejected  by  some  iron-masters.  One  is  com- 
pact, heavy,  and  black,  from  the  admixture  of  coaly  matter,  and  exhibits,  Mhen  broken,  a 
coarsely  pisiform  fracture.  A  second  is  compact  and  crystalline,  not  unlike  the  darkest- 
colored  mountain  limestone  of  South  Wales  in  appearance.  The  third  is  similar  in  struc- 
ture to  the  first-named  variety ;  the  granules,  consisting  of  iron  pyrites,  are  mixed  with 
coaly  matter,  and  cemented  together  by  a  mineral  substance,  similar  in  composition  to  the 
foregoing  ores.  It  is  from  the  yellow  color  of  this  variety  that  the  name  brass  has  been 
assigned  to  the  ores  by  the  miners. 

The  ores  have  respectively  the  following  composition  : — 


I. 

II. 

III. 

68-71 

59-73 

17-74 

0-42 

0-37 

- 

9-36 

11-80 

14-19 

11-80 

15-55 

12-06 

0-22 

trace 

49-72 

0-17 

0-23 

trace 

8-87 

9-80 

6-10 

— 

2-70 

99-55 

100-18 

99-81 

Carbonate  of  iron 
Carbonate  of  manganese 
Carbonate  of  lime 
Carbonate  of  magnesia 
Iron  pyrites 
Phosphoric  acid 
Coaly  matter 
Clay  .... 


"  It  is  unnecessary  to  allude  to  the  third  variety  ;  as  an  iron-making  material,  its  color 
admits  of  its  being  at  all  times  separated  from  the  others.  The  pyrites  which  it  contains, 
we  may  remark,  is  bisulphuret  of  iron. 

"  It  is  to  the  ores  I.  and  II.  that  we  would  direct  attention.  The  reason  of  their  having 
hitherto  been  comparatively  disregarded  may  be  attributed  either  to  their  having  been  mis- 
taken for  the  so-called  brass  of  coal,  or  to  their  being  difficult  to  work  in  the  blast-furnace 
in  the  ordinary  manner,  through  the  belief  that  they  were  similar  in  construction  to  the 
argillaceous  ores  of  the  di.strict.  It  will  be  seen  from  the  above  analyses  that  they  are 
varieties  of  spathic  iron  ore,  in  which  the  manganese  has  been  replaced  by  other  bases.  If 
treated  judiciously,  they  would  smelt  with  facility,  and  afford  an  iron  equal  to  that  produced 
from  the  argillaceous  ores.  From  the  large  amount  of  lime  and  magnesia  which  they  con- 
tain, their  employment  must  be  advantageous  in  an  economic  point  of  view. 


OOAL-GAS. 


353 


"  An  interesting  feature  in  these  ores  is  their  fusibility  during  calcination  on  the  large 

scale.     When  this  process  is  conducted  in  heaps,  the  centre  portions  are  invariably  melted. 

This,  considering  the  almost  entire  absence  of  silica,  is  apparently  an  unexpected  result. 

The  fused  mass  is  entirely  magnetic  and  crystalline.      Treated  with  acids,  it  dissolves  with 

great  evolution  of  heat. 

"  The  following  is  its  composition  : — 

Protoxide  of  iron -         -         -     38-28 

Sesquioxide  of  iron 32-50 

Protoxide  of  manganese 0-38 

Lime 12-84 

Magnesia 13-87 

Phosphoric  acid 0-17 

Sulphur 0-23 

Silicic  acid *•  -         -         -       1-20 

Alumina 0-51 


99-98 
''  From  the  above  analysis,  it  is  probable  that  the  fusibility  of  the  compound  is  owing  to 
the  magnetic  oxide  of  iron  acting  the  part  of  an  acid.     When  thoroughly  calcined  and  un- 
fused,  the  ores  retain  their  original  form  ;  and  if  exposed  to  the  air  for  any  length  of  time, 
crumble  to  powder  from  the  absorption  of  water  by  the  alkaline  earths." 

COAL-GAS.  Before  proceeding  to  describe  the  actual  processes  now  employed  for  the 
generation  of  illuminating  gas,  it  will  be  advisable  to  consider  briefly  the  general  scientific 
principles  involved  in  those  processes,  and  especially  the  chemical  relations  of  the  materials 
employed  for  the  generation  and  purification  of  illuminating  gas,  together  with  the  bearings 
of  chemistry  upon  the  operations  of  generating,  purifying,  and  burning  such  gas. 

The  Chemistry  of  Gas-Manufacture. — The  chief  materials  employed  in  the  manufacture 
of  gas  for  illuminating  purposes  are,  coal,  oil,  resin,  peat,  and  wood.  These  materials, 
although  very  dissimilar  in  appearance,  do  not  essentially  differ  from  each  other  in  their 
chemical  constituents,  they  may  all  be  regarded  as  consisting  chiefly  of  the  elements,  car- 
bon, hydrogen,  and  oxygen,  and  their  value  for  the  production  of  illuminating  gas  increases 
with  the  increase  of  the  proportion  of  hydrogen,  and  with  the  diminution  of  the  relative 
amount  of  oxygen.  Accordingly  we  find  that  oil  and  resin  generally  produce  gas  larger  in 
volume  and  better  in  quality  than  coal,  whilst  peat  and  wood,  owing  to  the  large  proportion 
of  oxygen  which  they  contain,  are  greatly  inferior  to  coal  for  the  purposes  of  the  gas  manu- 
facturer. The  relative  proportions  of  carbon,  hydrogen,  and  oxygen,  in  the  organic  part  of 
these  substances,  is  seen  from  the  following  comparison  : — 


Cannel  (Boghead) 

Cannel  (Wigau)     • 

Coal      - 

Oil 

Resin    - 

Peat      - 

Wood  - 


Percentage  of 

Percentaue  of 

Percentage  of 

Carbon. 

Hydrogen. 

Oxygen. 

80-35 

11-21 

6-71 

85-95 

5-75 

8-14 

88-15 

5-26 

5-41 

78-90 

10-97 

10-18 

79-47 

9-93 

10-59 

60-41 

5-57 

34-02 

50-00 

5-55 

44-45 

In  addition  to  the  three  essential  constituents  above  mentioned,  most  of  these  materials 
contain  small  and  variable  proportions  of  sulphur,  nitrogen,  and  inorganic  matter,  the  latter 
constituting,  when  the  substance  is  burnt,  what  we  term  at/t.  When  these  substances  are 
heated  to  redness,  they  undergo  decomposition,  a  considerable  quantity  of  inflammable 
gases  and  vapors  being  evolved,  whilst  a  residue,  consisting  of  carbon,  or  of  carbon  and 
ash,  remains  behind  in  the  solid  form.  When  atmospheric  air  has  free  access  during  this 
heating  operation,  the  inflammable  gases  and  vapors  burn  with  a  more  or  less  bright  flame, 
as  in  a  common  fire  ;  whilst  the  carbonaceous  residue  continued  afterwards  to  glow,  until 
nearly  the  whole  of  the  carbon  is  consumed.  If,  however,  the  application  of  heat  lie  made 
without  access  of  air,  by  inclosing  the  materials,  for  instance,  in  an  iron  retort  jirovided 
only  with  an  outlet  for  the  escape  of  gases,  the  decomposition  goes  on  in  much  the  same  man- 
.ner  as  before,  but  the  various  products  formed,  being  no  longer  exposed  to  the  simultaneous 
action  of  atmospheric  oxygen,  do  not  undergo  combustion  ;  the  inflammable  gases  and  vapors 
are  evolved  through  the  outlet  pipe  in  an  unburnt  condition,  and  the  carbonaceous  residue 
also  remains  unconsumed  in  the  retort.  Upon  cooling  the  gases  and  vapors  thus  evolved, 
the  latter  condense  more  or  less  into  liquids  which  separate  into  two  layers,  the  lower  one 
forming  a  dense  black  oily  fluid,  commonly  known  as  tar,  and  containing  several  solid 
Vol.  111.-23 


354 


COAL-GAS. 


hydrocarbons  partly  in  solution  and  partly  in  suspension ;  whilst  the  other  one  consist  i 
chiefly  of  an  aqueous  solution  of  salts  of  ammonia,  if  the  organic  matters  operated  upon 
contained  nitrogen.  Thus  the  volatile  products  of  this  process  of  destructive  distillation 
consist  of  solids,  liquids,  and  gases.     These  constituents  may  be  thus  tabulated : — 

I.  Gaseous. 
Name.  Chemical  Formula. 

Hydrogen H 

Light  carburetted  hydrogen         -         -         -     C^H* 
Carbonic  oxide CO 


defiant  gas 
Propylene 
Butylene    - 
Carbonic  aaid 
Sulphuretted  hydrogen 


C'H* 

C'H' 

C'H' 

CO' 

SH 


Aqueous  layer : 
Oily  layer : — 


Nitrogen N 

II.  Liquid. 
Name.  Chemical  Formula. 

-Water HO 

Bisulphide  of  carbon  ....  CS' 

Benzol C'=H^ 

Toluol C"H« 

Cumol C'*H"» 

Cymol C^^H" 

Aniline C'^H'N 

Picoline C'H'N 

Leucoline C^H'N 

Carbolic  acid C'^^O' 

Other  hydrocarbons CnHn* 

"  "  CnHn  +  2 

"  "  CnHn— 6 

III.  Solid. 

Name.  Chemical  Formula, 

In  aqueous  layer : — Carbonate  of  ammonia       ....  NH^OCO* 

"  Hydrosulphate  of  sulphide  of  ammonium   -  NH'S  +  HS 

"  Sulphite  of  ammonia  ....  NH^OSO' 

"  Chloride  of  ammonium       ....  NHTl 

In  oily  layer :—       Paraffine C'^H" 

Naphthaline C'°H' 

Paranaphthaline C=°H" 

Pvrene C=°H= 

Cbrysene C^'^H'" 

In  practice,  there  is  not  such  a  perfect  separation  of  the  products  as  is  represented  in 
the  above  table :  thus  a  small  proportion  of  the  gases  dissolves  in  the  liquid  products, 
whilst  most  of  the  liquids,  and  even  some  of  the  solids,  diffuse  themselves  in  the  form  of 
vapor,  to  a  certain  extent,  into  the  gases ;  and  the  solids  are  in  most  cases  almost  com- 
pletely dissolved  in  the  liquids.  The  relative  proportions  also  in  which  these  products 
occur  greatly  depend  upon  the  temperature  employed  in  the  destructive  distillation,  and  the 
length  of  time  during  which  the  volatile  products  are  exposed  to  it ;  a  low  temperature  and 
short  exposure  favoring  the  formation  of  solids  and  liquids,  whilst  a  higher  heat  and  longer 
exposure  determine  the  production  of  a  larger  proportion  of  gases  at  the  expense  of  the 
solids  and  liquids. 

The  usual  process  of  gas-making  consists  in  exposing  coal  or  cannel  to  a  bright-red  heat, 
in  close  vessels  of  convenient  size  and  shape,  until  all,  or  the  greater  part,  of  the  volatile 
matter  is  expelled.  Coke  is  the  material  left  in  the  retort,  and  the  matters  volatilized  con- 
sist of  condensible  vapors,  and  of  permanent  gases  more  or  less  saturated  with  these 
vapors.  By  a  simple  process  of  refrigeration  nearly  the  whole  of  the  vapors  may  be  readily 
condensed,  thus  separating  the  gases  more  or  less  perfectly  from  the  liquid  and  solid  pro- 
ducts of  the  distillation.  But  this  preliminary  process  of  purification  leaves  the  gases  still 
in  a  state  totally  unfitted  for  use  in  the  production  of  artificial  light.  They  still  retain  con- 
stituents, which  are  either  noxious  in  themselves,  or  generate  noxious  compounds  when 
they  arc  burnt,  such  as  sulphuretted  hydrogen,  sulphide  of  ammonium,  carbonate  of  ammo- 
nia, and  bisulphide  of  carbon.  They  also  contain  carbonic  acid,  which  greatly  diminishes 
the  amount  of  light  yielded  by  the  illuminating  gases  with  which  it  is  mixed. 

•  Here  n  means  an  even  number,  as  2,  4,  6,  <fcc 


COAL-GAS. 


355 


Besides  these  injurious  ingredients,  wliich  may  be  conveniently  included  in  the  term 
impurities,  there  are  others  which  do  not  contribute  any  thing  to  the  illuminating  power  of 
the  mixture,  and  which  may  be  denominated  diluents.  We  can  thus  classify  the  constitu- 
ents of  coal-gas  as  follows : — 


Illuminating  Ingredients. 

Diluents. 

Impurities. 

Olefiaiit  gas. 

Hydrogen. 

Sulphuretted  hydrogen. 

Propylene. 

Light  carburetted   hydro- 

Hydrosulphate of  sulphide  of 

Butylene. 

gen. 

ammonium. 

Hydrocarbon     vapors     of 

Carbonic  oxide. 

Carbonate  of  ammonia. 

the  formulae  CnHn   and 

Carbonic  acid. 

CnH(n  -  6). 

Vapor   of  bisulphide  of  car- 

Vapors of  hydrocarbons  of 

bon. 

the  formula  CaH(n  -  12.) 

Nitrogen. 
Oxygen. 
Aqueous  vapor. 

As  the  intelligent  manufacture  of  gas  for  illuminating  purposes  requires  a  knowledge  of 
the  leading  properties  of  the  compounds  included  under  the  three  heads  just  mentioned,  we 
will  now  proceed  briefly  to  describe  them. 

I.  Illuminating  Ingredients. 

Olefiant  Gas. — This  gas  has  been  proved  by  Berthelot  to  exist  in  coal-gas,  and  it  is 
probably  always  a  constituent  of  the  illuminating  gases  from  resin,  oil,  peat,  and  wood.  It 
is  occasionally,  though  rarely,  met  with  in  nature,  as  a  product  of  the  action  of  volcanic 
heat  upon  coal-bearing  strata ;  it  never  occurs,  however,  in  coal  strata  under  ordinary  cir- 
cumstances, and  no  trace  of  it  has  ever  been  met  with  amongst  the  gases  issuing  from  the 
coal  strata  of  this  country,  and  which  have  been  investigated  by  Graham,  Playfair,  and 
others.  Olefiant  gas  can  be  prepared  nearly  pure  by  heating  in  a  glass  retort  a  mixture  of 
1  part  by  weight  of  alcohol,  and  6  parts  of  oil  of  vitriol.  The  gas  must  be  passed  through 
solution  of  caustic  soda,  to  remove  sulphurous  and  carbonic  acids  with  which  it  is  generally 
contaminated. 

Olefiant  gas  is  colorless,  and  possesses  a  peculiar  and  slightly  unpleasant  odor.  Its  spe- 
cific gravity  is,  rather  less  than  that  of  atmospheric  air,  being  "9784  :  100  cubic  inches,  at 
60'  F.,  and  30  inches  barometrical  pressure,  weigh  30'3418  grains.  It  consists  of  two  vol- 
umes of  carbon  vapor  and  four  volumes  of  hydrogen,  the  six  volumes  being  condensed  to 
two.  It  contains,  in  a  given  bulk,  exactly  twice  as  much  carbon  as  is  contained  in  light 
carburetted  hydrogen.  Olefiant  ga.s  is  inflammable,  but  does  not  support  combustion : 
when  inflamed  as  it  issues  from  a  jet  into  the  atmosphere,  it  burns  with  a  white  flame,  emit- 
ting a  very  brilliant  light  without  smoke.  In  burning,  it  consumes  three  times  its  volume 
of  oxygen,  and  produces  twice  its  volume  of  carbonic  acid.  Exposed  to  a  full  red  heat,  as 
in  passing  through  a  red-hot  tube,  it  is  rapidly  decomposed,  carbon  being  deposited,  whilst 
hydrogen  and  light  carburetted  hydrogen  are  produced  ;  exposure  to  a  full  red  heat  conse- 
quently soon  entirely  destroys  its  illuminating  power. 

Propylene  and  Butylene. — The  first  of  these  highly  illuminating  constituents  of  coal-gas 
may  be  obtained  by  passing  the  vapor  oi  fusel  oil  through  a  red-hot  tube,  and  the  second 
by  the  electric  decomposition  of  valerate  of  potash.  Both  these  gases  are  colorless,  possess 
a  slight  ethereal  odor,  and  burn  with  a  brilliant  white  flame.  Like  olefiant  gas,  they  are 
rapidly  decomposed  at  a  briglit-red  heat,  depositing  much  carbon,  and  being  converted  into  the 
non-illuminating  gases — hydrogen  and  light  carburetted  hydrogen.  Propylene  consists  of 
three  volumes  of  carbon  vapor  and  six  volumes  of  hydrogen  condensed  to  two  volumes.  It 
therefore  contains,  in  a  given  volume,  one-half  more  carbon  than  olefiant  gas.  Its  specific 
gravity  is  1*45 11. 

Butylene  consists  of  four  volumes  of  carbon  vapor  and  eight  volumes  of  hydrogen,  the 
twelve  volumes  being  condensed  to  two  ;  it  consequently  contains,  in  a  given  volume,  twice 
as  much  carbon  as  olefiant  gas.     Its  specific  gravity  is  1-9348. 

Vapors  of  Hydroearbons  of  tlie  Form  Cnlln. — A  considerable  number  of  compounds 
having  this  formula  are  known  to  exist  in  coal-tar,  and,  as  many  of  them  are  very  volatile, 
they  must  be  diffused  as  vapors  in  coal-gas ;  but  as  they  have  not  yet  been  successfully  dis- 
entangled from  each  other,  no  account  of  their  individual  properties  can  be  given  ;  they 
all,  however,  contain  more  carbon  in  a  given  volume  than  butylene,  and  nmst  therefore 
contribute,  proportionally  to  their  volume,  a  greater  illuminating  power  than  any  of  the 
gaseous  hydrocarbons.  They  are  all  readily  decomposed  at  a  bright-red  heat,  chiefly  into 
carbon  and  non-illuminating  gases. 

Vapors  of  Hydrocarbons  <f  the  Formula  CnII(n-6). — These  consist  chiefly  of  benzol, 
toluol,  cumoi,  and  cymol,  compounds  which,  being  components  of  the  more  volatile  portion 


Propylene 

-     1-5 

Benzol  - 

Butvlene 

-     2-0 

Toluol  - 

Amvlene 

-     2-5 

Heptylene 

Hvdride  of  amvl     - 

-     2-5 

Cumol  - 

Ilvdride  of  bexyl   - 

-     3-0 

Cvmol   - 

He  xylene 

-     3-0 

Naphthaline 

II.  Dii 

UENTS. 

356  COAL-GAS. 

of  the  tar,  diflfuse  themselves  into  the  gaseous  products  of  distillation,  contributing  in  no 
inconsiderable  degree  to  the  total  illuminating  effect  of  the  gas.  The  composition  of  these 
substances  has  been  already  given  in  the  Table  ;  and  it  is  therefore  only  necessary  here  to 
remark,  that  benzol  vapor  contains,  in  a  given  volume,  three  times  as  much  carbon  as  ole- 
fiant  gas,  whilst  the  vapors  of  toluol,  cumol,  and  cvmol,  contain  respectively  3^,  4^,  and  5 
times  the  amount  of  carbon  contained  in  olefiant  gas.  For  a  further  account  of  these  and 
the  following  hydrocarbons,  see  Coal  Naphtha,  Destructivk  Distillatiox. 

Vapors  of  Hiidrocarbons  of  the  Fonnula  CnH(n-12. — The  only  vapor  of  this  compo- 
sition known  to  be  present  in  coal-gas  is  naphthaline,  (C'""!!'',)  which,  although  a  solid  at 
ordinary  temperatures,  yet  emits  a  considerable  quantity  of  vapor ;  in  fact,  its  presence 
occasions  to  a  great  extent  the  peculiar  odor  of  coal-gas. 

Naphthaline  is  a  frequent  source  of  serious  annoyance  to  the  gas  manufacturer,  by  con- 
densing in  the  street  mains  and  gradually  blocking  them  up,  or  so  narrowing  their  bore  as 
to  prevent  the  passage  of  the  needful  supply  of  gas.  This  effect  can  only  be  produced, 
wlien  the  gas  charged  with  naphthaline  vajjor  is  allowed  to  leave  the  holder  at  a  tempera- 
ture higlier  than  that  of  the  mains  through  which  it  subsequently  flows ;  but  as  this  cannot 
always  be  avoided,  the  prevention  of  such  deposits  might  perhaps  be  best  effected  by  pass- 
ing the  gas  over  a  large  surface  of  coal  oil  before  it  is  led  into  the  mains.  The  oil  would 
absorb  so  much  of  the  naphthaline  as  to  prevent  any  subsequent  deposition.  The  vapor  of 
naphthaline  contains,  in  an  equal  volume,  five  times  as  much  carbon  as  olefiant  gas.  The 
amount  of  light  yielded  by  these  illuminating  constituents  is  directly  proportionate  to  the 
amount  of  carbon  contained  in  an  equal  volume  of  each  ;  taking,  therefore,  the  illuuiinat- 
ing  power  of  olefiant  gas  as  unity,  the  following  numbers  exhibit  the  relative  illuminating 
values  of  equal  volumes  of  the  several  luminiferous  constituents  of  gas : — 

-  30 

-  3-5 

-  3-5 

-  4-0 

-  5-0 

-  5-0 


Hydrogen. — This  element  constitutes  one-ninth  of  the  total  weight  of  the  waters  of 
our  globe,  and  with  one  or  two  unimportant  exceptions,  enters  into  the  composition  of 
all  animal  and  vegetable  substances  and  of  the  products  derived  from  them,  as  peat,  coal, 
oils,  bitumen,  &c.  It  is,  however,  very  rarely  met  with  in  nature  in  a  free  or  uncombined 
state  ;  having  hitherto  only  been  thus  found  in  the  gases  emitted  from  volcanoes. 

Hydrogen  gas  may  be  obtained  in  abundance  and  nearly  pure  by  passing  steam  over 
iron,  zinc,  and  several  other  metals,  in  a  fine  state  of  division,  at  a  full  red  heat.  Mixed 
with  carbonic  oxide  and  carbonic  acid  gases,  it  is  also  generated  in  large  quantity  when 
steam  is  passed  over  charcoal,  coke,  or  other  carbonaceous  substances  at  a  red  heat.  In 
all  these  cases  the  watery  vapor  is  decomposed,  its  hydrogen  being  liberated,  whilst  its 
oxvgen  unites  with  the  metal  or  carbon,  forming  in  the  first  case  a  solid  non-volatile  oxide, 
which  encrusts  the  pure  metal,  and  soon  stops  further  action ;  in  the  second  case  a  gaseous 
oxide  of  carbon  is  generated,  and  passes  off  along  with  the  hydrogen,  thus  leaving  the 
carbon  freely  exposed  to  the  further  action  of  the  watery  vapor.  When  carbon  is  used, 
that  portion  of  the  steam  which  is  converted  into  hydrogen  and  carbonic  oxide  yields  its 
own  volume  of  each  of  these  gases ;  and  that  portion  which  forms  hydrogen  and  carbonic 
acid  affords  its  own  volume  of  hydrogen  and  half  its  own  voiume  of  carbonic  acid.  The 
amount  of  watery  vapor  which  undergoes  the  latter  decomposition  decreases  as  the  tem- 
perature at  which  the  operation  is  conducted  increases.  At  a  white  heat  scarcely  a  trace  of 
carbonic  acid  is  produced. 

Hydrogen  is  the  lightest  of  all  known  bodies,  its  specific  gravity  being  only  -0691  ;  100 
cubic  inches,  at  60^  Fahr.,  and  30  inches  barometric  pressure,  weigh  only  2'1371  grains. 
It  has  a  powerful  affinity  for  oxygen,  but  develops  scarcely  any  light  during  combustion  ; 
when,  however,  solid  substances,  such  as  lime,  magnesia,  or  platinum,  are  held  in  the  flame 
of  hydrogen,  considerable  light  is  emitted.  Burnt  in  air  or  oxygen  gas,  it  is  entirely  con- 
verted into  watery  vapor,  which  condenses  upon  cold  surfaces  held  above  the  flame. 

Lipht  Carburcttcd  Hi/dropen. — This  gas  consists  of  carbon  and  hydrogen  in  the  propor- 
tion of  6  parts  by  weigtit  of  the  former  element  combined  with  2  parts  of  the  latter. 
Owing  to  its  being  copiously  generated  in  marshy  swampy  places,  it  is  frequently  termed 
marsh  r/as,  and  from  certain  considerations  relative  to  its  chemical  constitution,  it  has  more 
recently  received  the  name  of  hydride  of  methyl.  It  enters  largely  into  the  composition 
of  coal-gas,  and  is  also  a  natural  product  of  the  slow  decomposition  of  coal,  and  of  putre- 
faction in  general.  Thus  it  occurs  in  enormous  quantities  in  the  coal  strata,  and  bubbles 
up  from  stagnant  pools  and  ditches  which  contain  putrefying  organic  remains.     As  thus 


COAL-GAS.  357 

generated,  it  is  mixed  with  small  quantities  of  carbonic  acid  and  nitrogen ;  it  can,  how- 
ever, be  artificially  prepared  perfectly  pure,  but  the  processes  need  not  be  described  here. 

Light  carburetted  hydrogen  when  pure  is  colorless,  tasteless,  and  inodorous ;  it  is  neu- 
tral to  test  papers,  and  nearly  insoluble  in  water ;  its  specific  gravity  is  -5594,  and  100 
cubic  inches,  at  60'  Fahr.,  and  30  inches  barometric  pressure,  weigh  17 '4 166  grains.  It 
does  not  support  combustion  or  respiration,  but  is  inflammable,  burning  with  a  blue,  or 
slightly  yellow  flame,  yielding  scarcely  any  light.  Mixed  with  a  due  proportion  of  atmos- 
pheric air  or  oxygen,  and  ignited,  it  explodes  with  great  violence :  the  products  of  its  com- 
bustion are  water  and  carbonic  acid. 

When  light  carburetted  hydrogen  is  exposed  to  a  white  heat,  it  is  slowly  decomposed, 
depositing  carbon,  and  yielding  twice  its  volume  of  hydrogen. 

Carbonic  Oxide. — this  gas  consists  of  0  parts  by  weight  of  carbon,  and  8  parts  of 
oxygon.  It  is  formed  when  carbon  is  consumed  in  a  limited  quantity  of  air  or  oxygen,  and 
is  also  generated,  as  stated  above,  when  steam  is  passed  over  ignited  coke  or  charcoal,  or 
when  coal  tar  and  steam  meet  in  a  red-hot  vessel.     It  is  always  a  constituent  of  coal-gas. 

Carbonic  oxide  is  a  colorless  and  inodorous  gas,  rather  lighter  than  atmospheric  air, 
and  having  exactly  the  specific  gravity  of  olefiant  gas,  -9727  ;  it  is  very  sparingly  soluble 
in  water,  but  is  very  soluble  in  aramoniacal  solution  of  chloride  of  copper.  Carbonic  oxide 
is  inflammable,  burning  with  a  beautiful  blue  flame  almost  devoid  of  light ;  the  product  of 
its  combustion  is  carbonic  acid.     It  is  said  to  be  very  poisonous. 

III.  Impurities. 

Sulphuretted  Hydrogen. — Tliis  gas  consists  of  sixteen  parts  of  sulphur  and  one  part  of 
hydrogen :  it  may  be  produced  by  passing  hydrogen  along  with  the  vapor  of  sulphur 
through  a  red-hot  tube,  but  it  is  best  prepared  pure  by  decomposing  proto-sulphuret  of 
ii-on  with  dilute  sulphuric  acid,  and  collecting  the  evolved  gas  at  the  pneumatic  trough  or 
over  mercury.     It  is  always  an  ingredient  in  crude  coal,  peat,  or  wood-gas. 

Sulphuretted  hydrogen  is  a  colorless  gas,  of  a  very  nauseous  odor,  resembling  that  of 
putrid  eggs;  its  specific  gravity  is  ri747.  It  is  highly  inflammable,  burning  with  a  blue 
flame,  destitute  of  light,  and  generating  a  large  amount  of  sulphurous  acid :  it  is  chiefly 
this  latter  circumstance  which  renders  its  presence  in  coal-gas  objectionable.  It  is  readily 
absorbed  by  metallic  solutions,  by  hydrated  oxide  of  iron,  and  by  lime  both  in  the  wet  and 
dry  state,  and  is  easily  recognized  in  coal-gas  by  exposing  a  strip  of  paper  impregnated 
with  acetate  of  lead  to  a  stream  of  the  gas ;  if  the  paper  becomes  discolored,  sulphuretted 
hydrogen  is  present. 

Ilj/drosulphate  of  Sulphide  of  Ammonium. — This  copipound  is  formed  by  the  combina- 
tion of  equal  volumes  of  ammonia  and  sulphuretted  hydrogen.  It  consists  of  14  parts  by 
weight  of  nitrogen,  15  of  hydrogen,  and  32  of  sulphur.  It  is  always  largely  produced  in 
the  manufacture  of  coal-gas,  but  is  almost  completely  condensed  and  retained  in  the  aque- 
ous layer  of  liquid  products,  contributing  principally  to  the  unbearable  odor  of  f/as  liqxior ; 
a  mere  trace  of  this  body  is  therefore  present  in  crude  coal-gas.  When  quite  pure  it  is  a 
colorless  crystalline  solid,  very  soluble  in  water,  and  volatile  at  ordinary  temperatures.  Its 
vapor,  when  present  in  coal-gas,  is  absorbed  and  decomposed  by  hydrate  of  lime  both  in 
the  wet  and  dry  state,  ammonia  being  liberated.  It  is  also  decomposed  by  acids,  but  in  this 
case  the  ammonia  is  retained  by  the  acid,  whilst  sulphuretted  hydrogen  is  evolved. 

Carbonic  Acid. — This  gas  is  met  with  in  nature  as  a  constituent  of  atmospheric  air,  and 
is  produced  in  large  quantities  during  the  earlier  stages  of  the  formation  of  coal  in  the 
earth's  strata.  Thus,  in  the  lignite  districts  of  Germany,  it  is  copiously  evolved,  and  meet- 
ing with  water  in  its  passage  to  the  surface,  it  is  absorbed,  and  forms  those  sparkling  min- 
eral springs  commonly  known  as  seltzer-water. 

Carbonic  acid  is  also  formed  during  fermentation,  by  the  combustion  of  carbon  in  air, 
and  in  the  decomposition  of  water  by  carbon  at  a  red  heat. 

At  ordinary  temperatures  carbonic  acid  is  a  colorless  and  invisible  gas,  but  it  may  be 
liquefied  by  ^ery  intense  cold  or  pressure.  It  consists  of  6  parts,  by  weight,  of  carbon 
united  with  16  p.irts  of  oxygen,  and  thus  differs  from  carbonic  oxide  by  containing  twice  as 
much  oxygen  as  the  latter  gas.  By  passing  carbonic  acid  over  ignited  coke,  charcoal,  or 
other  carbonaceous  matters,  it  takes  up  as  much  carbon  as  it  already  contains,  and  becomes 
converted  into  carbonic  oxide ;  but  it  is  impossible  in  this  way  to  convert  the  whole  of  the 
carbonic  acid  into  carbonic  oxide  unless  the  process  be  very  frequently  repeated.  Carbonic 
acid  is  ptmgent,  acidulous,  and  .soluble  in  anc(iual  bulk  of  water,  to  which  it  communicates 
that  briskness  which  we  so  much  admire  in  soda-water ;  it  is  consideraljly  heavier  than 
-  atmospheric  air,  its  specific  gravity  being  r524.  This  gas  is  uninflanuiiable,  and  cannot 
support  combustion  or  animal  life.  Its  acid  properties  arc  not  strongly  developed,  but  it 
unites  readily  with  alkaline  bases,  forming  carbonates :  it  is  upon  this  i)ropcrty  that  the 
removal  of  carbonic  acid  from  coal-gas  depends.  On  jixssing  coal-g;is  containing  this  acid 
through  slaked  lime  in  fine  powder,  or  through  milk  of  lime,  the  whole  of  the  carbonic  acid 
dis;ip])cars,  having  united  with  the  lime.  Quick-lime,  slaked  in  such  a  manner  as  to  be 
neither  dust-dry  nor  very  perceptibly  moist,  is  most  effective  for  the  absorption  of  high  per- 


358  COAL-GAS. 

centages  of  carbonic  acid,  a  layer  three  inches  in  thickness  not  allowing  a  trace  of  the  acid 
gas  tu  pass  through  it. 

The  presence  even  of  a  small  percentage  of  carbonic  acid  in  coal-gas  is  much  to  be 
deprecated,  on  account  of  the  great  loss  of  light  which  it  occasions,  1  per  cent,  of  carbonic 
acid  diminishing  the  illuminating  power  of  coal-gas  to  the  extent  of  about  6  per  cent.  ;  the 
addition  which  it  makes  to  the  carbonic  acid  produced  during  combustion  is,  however,  too 
minute  to  be  of  any  importance. 

Carbonate  of  Ammonia. — During  the  destructive  distillation  of  coal,  a  considerable  pro- 
portion of  the  nitrogen  contained  in  the  coal  is  converted  into  carbonate  of  ammonia,  the 
greater  part  of  wliich  condenses  in  the  aqueous  layer  of  liquid  products ;  but  as  carbonate 
of  ammonia  is  very  volatile,  even  at  ordinary  temperatures,  crude  coal-gas  always  contains  a 
small  quantity  of  this  compound.  It  is  a  volatile,  white,  crystalline  solid,  very  soluble  in 
water,  and  possessing  a  pungent  smell  like  ammonia.  Its  vapor  is  decomposed  by  lime, 
which  unites  witli  carbonic  acid,  liberating  ammonia.  The  presence  of  this  salt,  or  of  am- 
monia, in  coal-gas,  is  very  undesirable,  as  it  corrodes  brass  fittings,  and  is  also  partially  con- 
verted into  nitrous  acid  during  the  combustion  of  the  gas. 

Bhulphide  of  Carbon. — This  compound  consists  of  6  parts,  by  weight,  of  carbon,  and 
32  parts  of  sulphur  ;  it  is  formed  whenever  sulphur  and  carbonaceous  matter  are  brought 
together  at  a  bright-red  heat,  and  therefore,  owing  to  the  presence  of  sulphur  in  all  varieties 
of  coal,  its  vapor  is  generally,  and  probably  alwaj^s,  present  in  coal-gas.  Bisulphide  of  car- 
bon is  a  colorless  liquid,  of  a  most  insupportable  odor,  resembling  garlic ;  it  is  very  volatile, 
boiling  at  lOS'.  It  docs  not  mix  with  water,  but  dissolves  in  alcohol  and  ether  ;  it  is  also 
very  soluble  in  solution  of  caustic  soda  or  potash  in  methylic,  ethylic,  or  amylic  alcohol. 
It  is  very  inflammable,  and  generates  during  combustion  much  sulphurous  acid :  on  this 
account  its  presence  in  coal  gas  is  very  injurious,  and  as  there  is  no  known  means  of  remov- 
ing it  on  a  large  scale  by  any  mode  of  purification,  its  non-generation  in  the  process  of  gas- 
making  becomes  a  problem  of  great  importance.  Few  attempts  have  yet  been  made  to 
solve  this  difficulty,  hut  Mr.  Wright,  the  eminent  engineer  of  the  Western  Gas  Company, 
has  observed  that  its  formation  is  greatly  hindered,  if  not  entirely  prevented,  by  the  em- 
ployment of  a  somewhat  moderate  temperature.  In  corroboration  of  this  observation  it  has 
frequently  been  noticed  that  the  gas  furnished  by  companies  who  use  a  high  heat  contains  a 
very  large  quantity  of  this  noxious  material,  whilst  gas  generated  at  lower  temperatures,  as, 
for  instance,  that  produced  by  White's  hydrocarbon  process,  contains  mere  traces  of  this 
compound.  Although  no  process  for  the  absorption  of  bisulphide  of  carbon  vapor  from 
coal-gas  is  sufficiently  cheap  for  employment  on  a  large  scale,  yet  advantage  might  be  taken 
of  its  solubility  in  a  solution  of  caustic  potash  in  fusel  oil  (a  by-product  in  spirit  distilleries) 
or  in  methylated  spirit  of  wine,  for  its  removal  from  the  gas  supplied  to  private  houses, 
where  the  damage  done  by  the  sulphurous  acid  is  most  annoying.  By  passing  the  gas  over 
a  considerable  surface  of  this  solution,  contained  in  a  small  private  purifier,  the  bisulphide 
of  carbon  vapor  is  completely  removed. 

Bisulphide  of  carbon  vapor  can  be  readily  detected  in  coal-gas  by  a  very  simple  appa- 
ratus devised  by  Mr.  Wright  :*  in  this  instrument  the  products  of  the  combustion  of  a  jet 
of  gas  are  made  to  pass  through  a  small  Licbig's  condenser ;  if  the  liquid  dropping  from 
this  condenser  strongly  reddens  blue  litmus-paper,  it  is  highly  proliable  that  bisulphide  of 
carbon  is  present.  As  a  decisive  test,  50  or  60  drops  of  the  condensed  fluid  should  be  col- 
lected in  a  small  test-tube,  and  a  few  drops  of  pure  nitric  acid  added  :  on  heating  this  mix- 
ture to  boiling  over  a  spirit-lamp,  and  then  adding  a  drop  or  two  of  a  solution  of  chloride 
of  barium,  the  rKjuid  will  become  more  or  less  milky  if  bisulphide  of  carbon  has  been  pres- 
ent in  the  gas.  It  is  necessary  here  to  remark,  that  the  absence  of  sulphuretted  hydrogen 
must  be  first  ascertained  by  the  non-coloration  of  paper  imbued  with  acetate  of  lead,  and 
held  for  some-minutes  in  a  stream  of  the  gas. 

Nitroffcn. — Tliis  gas  is  the  chief  constituent  of  atmospheric  air,  ICO  cubic  feet  of  air 
containing  rather  more  than  79  cubic  feet  of  this  gas.  It  also  entei-s  into  the  composition 
of  a  large  number  of  animal  and  vegetable  substances.  All  descriptions  ^  coal  contain 
small  quantities  of  this  element.  When  nitrogen  is  eliminated  from  combination  in  contact 
with  oxvgen,  it  usually  takes  the  form  of  nitrous  or  nitric  acid  ;  whilst  in  contact  with  an 
excess  of  hydrogen  it  generates  ammonia.  It  is  in  this  latter  form  that  it  is  eliminated 
from  coal  in  the  process  of  gas  generation. 

Nitrogen  is  a  colorless,  inodorous,  and  tasteless  gas,  of  specific  gravity  0  976.  It  is  in- 
combustible under  ordinary  circumstances,  and  instantaneously  extinguishes  burning  bodies. 
Under  certtiin  conditions,  however,  nitrogen  does  undergo  combustion,  as  when  it  is  exposed 
to  a  very  intense  heat  in  the  presence  of  oxygen.  This  occurs,  for  instance,  when  a  small 
quantity  of  nitrogen  is  added  to  a  mixture  of  hydrogen,  with  a  somewhat  larger  proportion 
of  oxygen  than  is  requisite  to  form  water,  and  the  mixture  then  ignited  :  a  loud  explosion 
takes  place,  and  a  considerable  quantity  of  nitric  acid  is  formed,  owing  to  combustion  of  the 

*  This  instrument  can  be  had  on  application  to  Mr.  Wright,  65  and  65a,  Millbank  Street,  Westmin- 
Bter,  S.  W. 


COAL-GAS. 


359 


nitrogen,  or,  in  other  words,  its  union  with  oxygen  gas.  This  formation  of  nitric  acid  pos- 
sibly occurs  also  to  a  limited  extent  during  the  burning  of  coal-gas  ;  and  as  the  temperature 
required  to  form  nitric  acid  is  very  high,  the  greater  the  volume  of  gas  consumed  from  one 
burner  in  a  given  time,  the  greater  will  be  the  relative  (juantity  of  nitric  acid  produced. 
The  formation  of  such  a  corrosive  material  as  nitric  acid  under  these  circumstances  shows 
the  importance  of  preventing  the  admixture  of  the  products  of  the  combustion  of  coal-gas 
with  the  atmosphere  of  the  apartments  in  which  it  is  consumed.  The  nitrogen  contained 
in  coal-gas  is  due  entirely  to  the  admission  of  atmospheric  air,  and  not  to  the  elimination 
of  the  nitrogen  contained  in  the  coal ;  for  this  latter  nitrogen  appears  to  be  evolved  only  in 
combination  with  hydrogen  as  anmionia.  As  nitrogen  is  incombustible,  it  is  not  only  a  use- 
less ingredient  in  coal-gas,  but,  owing  to  its  abstracting  heat  from  the  flame  of  such  gas,  it 
causes  a  diminution  of  light,  and  is  thus  decidedly  injurious.  Tlie  admixture  of  this  cle- 
ment ought  therefore  to  be  avoided  as  much  as  possible. 

Oxygen. — This  element  is  always  present  in  coal-gas,  although  in  very  small  quantity  if 
the  manufacture  be  properly  conducted.  It  is  never  evolved  from  the  coal  itself,  Ijut  it 
makes  its  way  into  the  gas  through  leaky  joints,  and  also  to  a  certain  extent  through  the 
water  in  which  the  holders  are  immersed.  Its  presence  is  highly  injurious  to  the  illuminat- 
ing power  of  the  gas ;  and  since,  when  once  introduced,  it  cannot  be  abstracted  by  any 
practicable  means,  its  admixture  ought  to  be  carefully  guarded  against. 

Oxygen  is  a  colorless,  invisible,  and  inodorous  gas,  very  sparingly  soluble  in  water,  and 
which  has  hitherto  resisted  all  attempts  to  liquefy  it  by  cold  or  pressure.  It  is  evolved 
from  the  leaves  of  plants  under  the  influence  of  light,  and  constitutes  about  one-fifth  of  the 
bulk  of  our  atmosphere.  By  far  the  largest  amount  of  oxygen  however  exists  in  combina- 
tion with  other  elements ;  thus  eight  out  of  every  nine  tons  of  water  are  pure  oxygen,  and 
it  forms  at  least  one-third  of  the  total  weight  of  the  mineral  crust  of  our  globe.  It  is  there- 
fore the  most  abundant  of  all  elements.  Oxygen  gas  is  heavier  than  atmospheric  air;  100 
cubic  inches,  at  60"  Fahr.  and  30  inches  barometric  pressure,  weigliing  34'193  grains, 
whilst  100  cubic  inches  of  the  latter  weigh  only  31 'Oil?  grains.  The  specific  gravity  of 
oxygen  is  1'1026.  It  eminently  supports  combustion,  all  combustible  bodies  when  intro- 
duced into  it  burning  much  more  vividly  than  in  common  air;  indeed  it  is  owing  to  the 
presence  of  this  gas  in  our  atmosphere,  that  common  air  possesses  the  property  of  support- 
ing combustion. 

Aqueous  vapor. — Water  is  volatile  at  all  natural  temperatures,  and  therefore  its  vapor 
always  exists  to  a  greater  or  less  extent  diffused  in  coal-gas,  even  as  delivered  to  the  con- 
sumer. The  percentage  amount  of  aqueous  vapor  thus  present  in  coal-gas  is  always  small, 
even  when  the  gas  is  saturated ;  nevertheless  the  presence  of  even  this  small  proportion  of 
aqueous  vapor  diminishes  to  a  certain  extent  the  light  produced  by  the  combustion  of  gas. 
This  effect  is  no  doubt  owing  to  the  action  of  aqueous  vapor  upon  carbon  at  a  high  temper- 
ature, by  which  action  hydrogen,  carbonic  oxide,  and  carbonic  acid  gases  are  produced. 
The  presence  of  aqueous  vapor  therefore  tends  to  reduce  the  number  of  particles  of  carbon 
floating  in  the  gas  flame,  and  consequently  the  light  is  diminished.  The  following  table 
shows  the  maximum  percentages  of  aqueous  vapor  which  can  be  present  in  gas  at  diiferent 
temperatures.  As  a  general  rule  the  gas  will  contain  the  maximum  amount  at  the  lowest 
temperature  to  which  it  has  been  exposed  in  its  passage  from  the  retorts  to  the  burners. 


Percentage 

Percentage 

Percentage 

Temperature. 

of  aqueous 

Temperature. 

of  aqueous 

Temperature. 

of  aqueous 

vapor. 

vapor. 

vapor. 

32"  F. 

0-6 

42"  F. 

0-9 

52°  F. 

1-3 

33° 

0-6 

43° 

0-9 

53" 

1-3 

34" 

0-7 

44" 

1-0 

54" 

1-4 

35" 

0-7 

45° 

1-0 

55° 

1-4 

36° 

0-7 

4G° 

ro 

56" 

1-5 

37" 

0-7 

47" 

M 

57" 

1-5           1 

38° 

0-8 

48" 

1-1 

58" 

1-6 

39" 

0-8 

49° 

11 

59" 

1-7          1 

40" 

0-8 

50" 

1-2 

CO" 

1-8           j 

41* 

0-9 

51" 

1-2 

1 

Aqueous  vapor  has  a  specific  gravity  of  '6201,  and  one  cubic  foot  of  it  contains  one 
cubic  foot  of  hydrogen  and  half  a  cubic  foot  of  oxygen.  In  contact  with  ignited  carbon,  or 
cailionaccous  substances,  it  is  decomposed ;  producing  a  mixture  of  hydrogen,  carbonic 
oxide,  and  carbonic  acid  gases.  When  passed  over  ignited  iron  it  yields  its  own  volume  of 
nearlj'  pure  hydrogen. 

Having  thus  described  the  more  important  properties  of  the  constituents  of  coal-gas, 


360 


COAL-GAS. 


we  are  now  prepared  to  discuss  the  conditions  involved  in  the  generation,  purification,  and 
combustion  of  gas. 

0)1  the  generation  of  illuminating  gas. — The  production  of  gas  for  illuminating  pur- 
poses, whether  derived  from  coal,  peat,  wood,  or  oil,  depends,  as  we  have  seen,  upon  a  re- 
arrangement of  the  elements  composing  the  mateiial  employed.  The  nature  of  this  re- 
arrangement is  dependent  upon  the  temperature  employed.  The  lower  the  heat  at  which  it 
can  be  effected,  the  less  the  weight  of  coke  or  carbonaceous  residue  left  in  the  retort,  and, 
consequently,  the  greater  the  amount  of  carbon  remaining  combined  with  the  hydrogen; 
the  hydro-carbons  thus  formed  being  chiefly  solids  and  liquids.  On  the  other  hand,  the 
higher  the  temperature  employed,  the  greater  is  the  weight  of  carbonaceous  residue,  and, 
therefore,  the  smaller  is  the  amount  of  carbon  contained  in  the  volatilized  matters,  whilst 
the  proportion  of  gases  in  these  latter  becomes  larger  as  the  temperature  increases.  By 
employing  a  very  low  temperature  for  the  destructive  distillation,  the  production  of  gas 
may  be  almost  entirely  prevented,  whilst  by  the  employment  of  a  very  high  temperature 
the  three  chief  constituents  of  coal  might  without  doubt  be  completely  converted  into  coke, 
carbonic  oxide,  and  hydrogen.  Now  the  results  produced  by  both  these  extremes  of  tem- 
perature are  valueles.s  to  the  gas  manufacturer,  and  it  is  therefore  necessary  to  employ  a 
heat  sufficiently  high  to  prevent  as  much  as  possible  the  volatile  substances  iVom  escaping 
in  the  form  of  condensiblc  vapors,  but  not  high  enough  to  decompose  the  luminiferous  con- 
stituents of  the  evolved  gas.  If  coal  were  a  definite  and  single  chemical  compound,  and 
could  1)0  so  exposed  to, heat  as  to  suddenly  raise  the  temperature  of  every  particle  to  a  uni- 
form and  definite  degree,  it  is  highly  probable  that  the  results  of  the  distillation  would  be  far 
less  complex  than  they  are  in  the  present  mode  of  gas  manufacture;  and  it  might  even  be 
possible  to  find  such  a  degree  of  temperature  as  would  convert  the  whole  of  the  hydrogen  into 
one  or  more  of  the  higher  gaseous  compounds  of  carbon,  thus  giving  results  of  maximum 
value  to  the  gas-manufacturer.  In  the  ordinary  processes  of  gas-making,  where  a  charge  of 
several  cwts.  of  coal,  often  in  large  lumps,  is  thrown  into  an  ignited  retort,  it  is  impossible  to 
attain  any  such  uniform  temperature.  The  heat  is  conducted  very  gradually  to  the  interior  of 
the  mass  of  coal,  and  therefore  various  portions  of  the  charge  are  exposed  to  very  unequal 
temperatures,  especially  in  the  earlier  stages  of  the  distillation.  The  natural  consequence  of 
these  conditions  is  the  production,  on  the  one  hand,  of  products  resulting  from  excessive 
temperature,  viz.  :  hydrogen  and  light  carburctted  hydrogen,  and  on  the  other,  of  tar, 
which  may  be  regarded  as  the  consequence  of  deficient  heat.  Notwithstanding  several 
attempts,  these  disadvantages  have  not  yet  been  successfully  overcome,  but  the  importance 
of  a  practical  process  which  would  secure  a  tolerably  uniform  temperature  during  the  whole 
course  of  distillation,  is  seen  from  the  remai-kable  results  obtained  with  Clegg's  revolving 
web  retort — a  form  of  apparatus  undoubtedly  the  most  ingenious  yet  invented  for  the  pro- 
duction of  gas,  and  which,  although  in  its  present  form  too  complicated  for  successful  prac- 
tical use,  yet  embodies,  when  we  consider  the  early  date  of  its  invention,  in  a  remarkable 
manner,  the  true  scientific  principles  of  gas-making.  This  retort,  of  which  a  description 
will  lie  found  at  p.  381,  obviated  to  a  great  extent  the  inequality  and  uncertainty  of  temper- 
ature in  the  ordinary  gas  retorts,  and  the  result  was  an  increase  of  from  30  to  40  per  cent, 
in  the  quantity  of  gas  produced,  the  quality  being  also  improved,  whilst  scarcely  any  tar 
was  formed. 

But  besides  the  great  influence  exercised  by  the  temperature  to  which  coal  is  exposed  in 
the  process  of  gas-making,  the  length  of  time,  during  which  the  volatile  products  of  decom- 
position are  exposed  to  that  temperature,  is  a  most  important  circumstance  as  regards  the 
successful  manufacture  of  gas.  If  we  take  into  consideration  the  behavior  of  the  luminif- 
erous constituents  of  gas  when  exposed  to  a  blight  red  heat,  and  which  has  been  described 
above,  it  will  be  evident  that  a  second  most  important  condition  in  the  manufacture  of  gas 
is  the  rapid  removal  of  these  luminiferous  constituents  from  the  destructive  influence  of  the 
red-hot  retort  as  soon  as  they  are  generated :  every  second  duiing  which  these  gases  are  al- 
lowed to  remain  in  their  birthplace  diminishes  their  value  as  illuminating  agents.  The  oidy 
method  hitherto  employed  for  the  rapid  removal  of  the  gases  from  the  retorts  is  White's 
process,  the  mechanical  details  of  which  are  fully  described  below.  This  process  consists 
essentially  in  transmitting  a  current  of  leater  gas  through  the  retorts  in  which  coal  or  can- 
nel  gas  is  being  generated.  The  water  gas  is  produced  by  transmitting  steam  through  re- 
torts filled  with  coke  or  charcoal,  and  consists  of  a  mixture  of  hydrogen,  carbonic  oxide, 
and  carbonic  acid  gases.  These  gases,  which  are  not  in  themselves  luminiferous  on  com- 
bustion, necessarily  become  mixed  with  the  coal  or  cannel  gas,  and  thus  diminish  the  illu- 
minating power  of  the  latter  whilst  they  increase  its  volume.  Nevertheless,  if  the  admission 
of  water  gas  be  properly  managed,  the  luminiferous  constituents  saved  from  destruction  by 
their  rapid  removal  from  the  retorts,  compensate  for  the  dilution  of  the  gas,  so  as  to  render 
the  diluted  gas  equal  in  illuminating  power  to  the  gas  produced  from  the  same  coal  or  can- 
nel in  the  ordinary  process  of  manufacture.  When  canncls  yielding  very  highly  luminifer- 
ous gas  arc  employed,  it  is  desirable  to  dilute  them  to  a  much  greater  extent,  and  this  can 
be  easily  effected  by  admitting  into  the  coal  retort  a  larger  proportion  of  water  gas.     In 


COAL-GAS. 


86] 


some  cases  the  total  amount  of  light  yielded  by  the  gas  from  a  given  weight  of  coal  when 
treated  according  to  White's  process  is  more  than  double  that  obtained  by  the  ordinary  pro- 
cess, and  in  all  cases  the  gain  in  total  amount  of  light  is  very  large,  thus  showing  the  im- 
portance of  removing  the  gases  from  the  red-hot  retorts  as  rapidly  as  possible.  This  re- 
mark applies  especially  to  gases  very  rich  in  luminiferous  hydrocarbons,  because  such  gases 
suffer  relatively  much  more  deterioration  than  tliose  containing  a  larger  proportion  of  dilu- 
ents. In  addition  to  these  advantages  such  a  dilution  of  rich  cannel  gases  with  any  of  the 
non-luminous  constituents,  hydrogen,  carbonic  oxide,  or  light  carburetted  hydrogen,  in- 
creases the  illuminating  power  of  the  gas  in  another  way :  this  is  effected  by  their  forming 
a  medium  for  the  solution  of  the  vapors  of  such  hydrocarbons  as  exist  in  the  liquid  or  even 
solid  state  at  the  ordinary  temperature  of  the  atmosphere,  and  they  thus  enable  us  to  con- 
vert an  additional  quantity  of  illuminating  materials  into  the  gaseous  form,  which  they 
retain  permanently,  unless  the  temperature  foil  below  the  point  of  saturation.  The  gain  in 
illuminating  power  which  is  thus  obtained  will  be  perhaps  better  seen  from  the  following 
example: — Suppose  100  cubic  inches  of  oleliant  gas  were  allowed  to  saturate  itself  with  the 
vapor  of  a  volatile  hydrocarbon,  containing  three  times  as  much  carbon  in  a  given  volume 
of  its  vapor  as  that  contained  in  an  equal  volume  of  olefiant  gas,  and  that  it  took  up  or 
dissolved  3  cubic  inches  of  this  vapor ;  then,  if  we  express  the  value  of  1  cubic  inch  of 
olefiant  gas  by  unity,  the  illuminating  power  of  the  103  cubic  inches  of  the  mixture  of  olefiant 
gas  and  hydrocarbon  vapor  will  be  109.  Now  if  we  mix  these  103  cubic  inches  with  100 
cubic  inches  of  hydrogen,  the  mixture  will  be  able  to  take  up  an  additional  3  cubic  inches 
of  hydrocarbon  vapor,  and  the  illuminating  power  of  the  206  cubic  inciies  will  then  become 
118;  thus  the  hydrogen  produces  a  gain  in  illuminating  power  equal  to  9  cubic  inches  of 
olefiant  gas,  or  neaily  4'5  per  cent,  upon  the  volume  of  mixed  gases.  When  we  consider 
that  coal  naphtha  contains  hydrocarbons  of  great  volatility,  and  that  these  are  the  surplus 
remaining  after  the  saturation  of  the  gas  from  which  they  have  condensed,  the  importance 
of  this  function  of  tlie  non-illuminating  class  of  combustible  gases  will  be  sufficiently  evi- 
dent. It  may  here  be  remarked  that  incombustible  gases  could  not  be  employed  for  this 
purpose,  since  their  cooling  influence  upon  the  flame  during  the  subsequent  burning  of  the 
gas  would  diminish  the  liglit  to  a  greater  extent  than  the  hydrocarljon  vapor  could  in- 
crease it. 

It  is  evident  that  all  the  three  non-illuminating  gases,  forming  the  class  of  diluents, 
would  perform  both  the  offices  here  assigned  to  them  perfectly  well,  and  therefore  we  have 
as  yet  seen  no  reason  for  giving  our  preference  in  favor  of  any  one  of  these  diluents;  if, 
however,  we  study  their  behavior  during  combustion,  we  shall  find  that  where  the  gas  is  to 
be  used  for  illuminating  purposes,  hydrogen  has  qualities  which  give  it  a  very  decided  pref- 
erence over  the  other  two.  When  gas  is  used  for  lighting  the  interior  of  public  buildings 
and  private  houses,  it  is  very  desirable  that  it  should  deteriorate  the  air  as  little  as  possible, 
or,  in  other  words,  it  should  consume  as  small  a  quantity  of  oxygen  and  generate  as  little 
caibonic  acid  as  possible.  The  oppressive  heat  which  is  so  frequently  felt  in  apartments 
lighted  with  gas  also  shows  the  advantage  of  the  gas  generating  a  minimmn  amount  of 
heat. 

The  following  is  a  comparison  of  the  properties  of  the  three  non-illuminating  gases  in 
reference  to  the  points  just  mentioned: — 

One  cubic  foot  of  light  carburetted  hydrogen,  at  GO"  Fahr.  and  30  inches  barometrical 
pressure,  consumes  2  cubic  feet  of  oxygen  during  its  combustion,  and  generates  1  cubic  foot 
of  carbonic  acid,  yielding  a  quantity  of  heat  capable  of  heating  5  lbs.  14  oz.  of  water  from 
32"  to  212",  or  causing  a  i-ise  of  temperature  from  60°  to  SO'S""  in  a  room  containing  2,500 
cubic  feet  of  air. 

One  cubic  foot  of  carbonic  oxide,  at  the  same  temperature  and  pressure,  consumes,  dur- 
ing combustion,  -J-  a  cubic  foot  of  oxygen,  generates  1  cubic  foot  of  carbonic  acid,  and 
affords  heat  capable  of  raising  the  temperature  of  1  lb.  14  oz.  of  water  from  32°  to  212°,  or 
that  of  2,500  cubic  feet  of  air  from  60°  to  66'6°. 

One  cubic  foot  of  hydrogen,  at  the  same  temperature  and  pressure,  consumes  -|  a  cubic 
foot  of  oxygen,  generates  no  carbonic  acid,  and  yields  heat  capable  of  raising  the  tempera- 
ture of  1  lb.  13  oz.  of  water  from  32°  to  212°,  or  that  of  2,500  cubic  feet  of  air  from  60°  to 
66-4°. 

This  comparison  shows  that  light  carburetted  hydrogen  is  very  objectionable  as  a  dilu- 
ent, not  only  on  account  of  the  carbonic  acid  which  it  generates,  but  also  by  reason  of  tlie 
very  large  quantity  of  oxygen  which  it  consumes,  and  the  very  great  amount  of  heat  which, 
-in  relation  to  its  volume,  it  evolves  on  combustion;  the  consumption  of  oxygen  being  four 
times,  and  the  absolute  thermal  effect  more  tha:i  three  times  as  great  as  that  of  either  of 
the  other  gases. 

The  quantity  of  heat  evolved  by  the  combustion  of  equal  volumes  of  carbonic  oxide  and 
hydrogen  is  nearly,  and  the  amount  of  oxygen  consumed  quite,  the  same;  but  the  carbonic 
acid  evolved  from  the  first  gives  a  decided  preference  to  hydrogen  as  the  best  diluent. 

The  same  comparison  also  shows  that  when  the  gas  ft  to  be  used  for  heating  purposes, 


862  COAL-GAS. 

and  the  products  of  combustion  are  carried  away,  light  carburetted  hydrogen  is  by  far  the 
best  dihient. 

Tlie  experiments  of  Dulong  on  the  absolute  thermal  effects  of  hydrogen,  light  carbu- 
retted hydrogen,  and  carbonic  oxide  are  taken  as  the  basis  of  the  foregoing  calculations. 
Dulong  ibund  that — 

1  lb.  of  hydrogen  raised  the  temperature  of  1  lb.  of  water  through  62471°  F. 
1  lb.  of  carbonic  oxide  "  "  "  4504°  F. 

1  lb.  of  light  carburetted  hydrogen  "  "  24244°  F. 

These  considerations  indicate  the  objects  that  should  chiefly  be  regarded,  in  the  gener- 
ating department  of  the  manufacture  of  gas  for  illuminating  purposes.     They  are — 

1st.  The  extraction  of  the  largest  possible  amount  of  illuminating  compounds  from  a 
given  weight  of  material. 

2d.  The  formation  of  a  due  proportion  of  illuminating  and  non-illuminating  constitu- 
ents, so  that  on  the  one  hand  the  combustion  of  the  gas  shall  be  perfect,  and  without  the 
production  of  smoke  or  unpleasant  odor,  and  on  the  other,  the  volume  of  gas  required  to 
obtain  a  certain  amount  of  light  shall  not  be  too  large. 

3d.  The  presence  of  the  largest  possible  proportion  of  hydrogen  amongst  the  non-illu- 
minating constituents,  to  the  exclusion  of  light  carburetted  hydrogen,  and  carbonic  oxide ; 
so  as  to  produce  the  least  amount  of  heat  and  atmospheric  deterioration  in  the  apartments 
in  which  the  gas  is  consumed. 

On  tfie  purifcation  of  ilhiminating  gas. — If  we  except  the  insignificant  quantities  of  ni- 
trogen and  oxygen,  which  become  mixed  with  illuminating  gas  through  imperfections  in  the 
joints  of  the  apparatus  employed,  and  by  the  transferring  power  of  the  water  of  the  gas- 
holder, all  impurities  arise  from  the  presence  of  the  three  elements  sulphur,  oxygen,  and 
nitrogen  in  the  generating  material  used. 

The  sulphur,  uniting  with  portions  of  the  hydrogen  and  carbon  of  the  coal,  generates 
with  the  first-named  element  sulphuretted  hydrogen,  and  with  the  second,  bisulphide  of 
carbon.  It  is  also  probable  that  volatile  organic  compounds  of  sulphur  are  produced  by 
the  union  of  this  element  with  carbon  and  hydrogen  simultaneously,  although  we  have  as 
yet  no  positive  evidence  of  their  presence  in  illuminating  gas.  The  oxygen,  uniting  with 
another  portion  of  carbon,  forms  carbonic  acid,  whilst  the  nitrogen  unites  with  hydrogen  to 
form  ammonia,  which,  by  combination  with  sulphuretted  hydrogen,  produces  hydrosulphate 
of  sulphide  of  ammonium,  and,  with  carbonic  acid  and  water,  carbonate  of  ammonia.  With 
the  exception  of  bisulphide  of  carbon  and  the  organic  sulphur  compounds  just  mentioned, 
the  removal  of  all  these  impurities  is  not  difficult.  Slaked  lime,  either  in  the  form  of  moist 
powder,  or  suspended  in  water  as  milk  of  lime,  absorbs  the  whole  of  them ;  whilst  It  has  no 
perceptible  effect  upon  the  other  constituents  of  the  gas.  By  this  process  of  purification 
the  sulphuretted  hydiogcn  and  caustic  lime  are  converted  into  sulphide  of  calcium  and 
water ;  the  former,  being  non-volatile,  does  not  mix  with  the  gas.  Hydrosulphate  of  sulphide 
of  ammonium  is  in  like  manner  converted  into  sulphide  of  calcium,  water,  and  ammonia: 
part  of  the  latter  is  retained  by  the  moisture  present  in  the  purifying  material,  but  the  re- 
mainder mixes  with  the  gas,  from  which,  however,  it  can  be  removed  by  contact  with  a  large 
surface  of  water.  Carbonic  acid  unites  with  caustic  lime  with  great  energy,  forming  car- 
bonate of  lime,  a  perfectly  non-volatile  material ;  and  thus  the  acid  gas  is  effectually  re- 
tained. Carbonate  of  ammonia  is  under  similar  circumstances  decomposed,  carbonate  of 
lime  being  formed  and  ammonia  liberated  ;  the  last,  as  before,  being  only  partially  retained 
by  the  moisture  present,  and  requiring,  when  "dry -lime"  is  used,  a  subsequent  application 
of  water  for  Its  complete  removal.  Although  in  the  wet  lime  purifying  process  a  given 
weight  of  lime  can  remove  a  much  larger  volume  of  Impurities,  yet  the  dry  lime  process  pos- 
sesses so  many  manipulatory  advantages  that  it  is  now  all  but  universally  employed  where 
lime  is  used  as  the  purifying  agent.  The  maximum  amount  of  sulphuretted  hydrogen  or 
of  carbonic  acid  which  can  be  absorbed  by  1  lb.  of  quick-lime,  in  the  so-called  dry  and  wet 
states  respectively.  Is  seen  from  the  following  table : — 


Cubic  feet  of 
Sulphuretted  hydrogen. 

-     0-78     - 

Cubic  feet  of 
Carbonic  acid. 
-     8-39 

-     6-78     - 

-     6-78 

1  lb.  of  quick -lime  used  as  dry  lime  absorbs 
1  lb.  of  quick-lime  used  as  wet  lime  absoi'bs 

In  practice,  however,  the  absorption  actually  effected  is,  even  under  the  most  favorable 
circumstances,  considerably  less  than  here  Indicated.  As  a  substitute  for  lime  in  the  puii- 
fication  of  gas  a  mixture  of  hydrated  peroxide  of  iron  and  sulphate  of  lime  has  lately  come 
Into  extensive  use.  This  material  is  prepared  in  the  first  place  by  mixing  slaked  lime  with 
hydrated  peroxide  of  iron,  the  composition  being  rendered  more  porous  by  the  addition  of 
a  certain  proportion  of  .sawdust.  This  mixture  is  now  in  a  condition  to  remove  those  im- 
pm-ities  from  coal-gas  which  are  abstracted  by  lime.  The  peroxide  of  iron  absorbs  sul- 
phuretted hydrogen  and  sulphide  of  ammonium  and  becomes  converted  into  sulphide  of  iron. 


COAL-GAS.  3G3 

The  slaked  lime  absorbs  carbonic  acid  and  carbonate  of  ammonia  until  it  is  converted  into 
subcarbonate  of  lime.  When  the  absorbing  powera  of  the  mixture  are  nearly  exhausted, 
the  covers  of  the  purifiers  are  removed  and  the  mixture  is  exposed  to  the  air.  The  follow- 
ing change  is  then  said  to  take  place.  The  sulphide  of  iron  rapidly  absorbs  oxygen  and  be- 
comes converted  first  into  sulphate  of  protoxide  of  iron,  and  finally  into  sulphate  of  perox- 
ide, which  latter  is  decomposed  by  the  carbonate  of  lime,  carbonic  acid  being  evolved  as 
gas,  whilst  sulphate  of  lime  and  peroxide  of  iron  are  produced ;  the  mixture  is  thus  again 
rendered  available  for  the  process  of  purification ;  the  peroxide  of  iron  acts  as  before,  but 
in  the  place  of  quick-lime  we  have  now  sulphate  of  lime,  which  is  quite  eftectual  for  the 
removal  of  carbonate  of  ammonia,  with  which  it  forms  carbonate  of  lime  and  sulphate  of 
ammonia ;  but  the  mixture  is  incapable  of  removing  free  carbonic  acid,  and  it  is  therefore 
necessary  to  provide  a  separate  dry  lime-purifier  for  the  removal  of  this  gas.  When  the 
purifying  material  is  again  saturated  with  the  noxious  gases,  another  exposure  to  atmos- 
pheric oxygen  restores  it  again  to  its  active  condition,  the  only  permanent  effect  upon  it 
being  the  accumulation  of  sulphate  of  ammonia  within  its  pores.  If  this  latter  salt  be  oc- 
casionally dissolved  out  with  water,  the  mixture  may  be  used  over  and  over  again  to  an 
almost  unlimited  extent.  It  has  been  found  that  this  process  can  be  much  simplified,  and 
Mr.  Hills,  who  has  brought  gas  purification  to  great  perfection,  recommends  that  hydrated 
peroxide  of  iron  should  be  merely  mixed  with  a  considerable  bulk  of  sawdust  and  placed  in 
the  purifiers.  After  the  gas  has  passed  through  this  mixture  for  18  hours,  it  is  shut  oif  and 
replaced  by  a  current  of  air  forced  through  by  a  fanner  for  3  hours.  The  sulphide  of  iron 
is  thus  oxidized,  sulphur  being  separated  and  hydrated  peroxide  of  iron  regenerated :  and 
the  purifying  material  being  now  revivified,  the  gas  may  be  passed  through  it  again  as  be- 
fore. In  this  way  it  is  only  found  necessary  to  remove  the  material  once  a  month  in  order 
to  separate  the  lowest  stratum  of  about  an  inch  in  thickness,  which  has  become  clogged 
up  with  tar.  A  proportional  quantity  of  fresh  mixture  of  hydrated  peroxide  of  iron  and 
sawdust  having  been  added,  the  whole  is  again  returned  to  the  purifier.  It  is  difficult  to 
conceive  a  more  simple  and  inexpensive  process  of  purification  than  this.  It  does  not,  how- 
ever, remove  carbonic  acid.  Several  other  materials  have  been  proposed  for  the  separation 
of  sulphuretted  hydrogen  from  coal-gas,  such  as  sulphate  of  lead,  and  chloride  of  manganese, 
but  they  possess  no  peculiar  advantages  and  have  never  been  extensively  adopted. 

It  has  been  already  mentioned  that,  in  addition  to  sulphuretted  hydrogen  and  carbonic 
acid,  which  are  readily  removed  by  the  processes  just  described,  there  also  exist  in  coal-gas, 
as  impurities,  variable  quantities  of  Ijisulphide  of  carbon  and  probably  sulphuretted  hydro- 
carbons. Now  all  these  sulphur  compounds  produce  sulphurous  acid  during  tlie  combus- 
tion of  the  gas,  and  where  the  quantities  of  these  impurities  are  considerable,  as  is  the  case 
■with  much  of  the  gas  now  manufactured,  the  atmosphere  of  the  apartments  in  which  such 
gas  is  used  becomes  so  strongly  impregnated  with  sulphurous  acid,  as  to  be  highly  offensive 
to  the  senses  and  very  destructive  to  art  decorations,  bindings  of  books,  &c.  It  becomes, 
therefore,  a  matter  of  considerable  importance  to  prevent,  as  far  as  possible,  the  occurrence 
of  these  injurious  constituents;  in  fact,  until  this  is  effected,  gas  will  never  be  more  than 
very  partially  adopted  as  a  means  of  illumination  in  dwelling-houses.  "When  once  gener- 
ated with  coal-gas  all  attempts  to  remove  these  constituents  have  hitherto  proved  ineffect- 
ual, and  there  seems  little  ground  for  hope  that  any  practical  process  will  be  devised  for 
their  abstraction.  Attention  may,  therefore,  more  profitably  be  directed  to  the  conditions 
which  tend  to  diminish  the  amount  generated  in  the  retorts,  or  altogether  to  prevent  their 
formation.  Mr.  Wright,  who  has  paid  considerable  attention  to  this  problem,  finds  that  the 
employment  of  a  moderate  heat  for  the  generation  of  the  gas  has  the  effect  of  greatly  re- 
ducing the  relative  quantity  of  these  noxious  ingredients,  and  thus,  by  simply  avoiding  ex- 
cessive heat  in  the  retorts,  and  rejecting  the  last  portions  of  gas,  he  lias,  to  a  great  extent, 
prevented  their  formation.  Unfortunately,  however,  this  remedy  is  not  likely  to  find  favor 
amongst  gas-manufacturers  in  general,  inasmuch  as  it  considerably  reduces  the  yield  of  gas. 
A  few  well-directed  chemical  experiments  could  scarcely  fail  to  discover  the  conditions 
necessary  for  the  non-production  of  these  sulphuretted  compounds.  Probably  the  proi)er 
admixture  of  salt  or  lime  with  the  coals  before  carbonization  would  have  the  desired  oflect. 
Tiie  subject  is  one  of  so  much  importance  to  the  future  of  gas  illumination,  that  it  ought 
n  )t  to  be  suffered  to  rest  in  its  present  unsatisfactory  condition. 

On  the  co)isumption  of  gaa. — The  proper  consumption  or  burning  of  illuminating  gas 
depends  upon  certain  physical  and  chemical  conditions,  the  due  observance  of  which  is  of 
great  importance  in  the  development  of  a  maximum  amount  of  light.  The  production  of 
artificial  light  depends  upon  the  fact  that,  at  certain  high  temperatures,  all  matter  becomes 
luminous.  The  higher  the  temperature  the  greater  is  the  intensity  of  the  light  emitted. 
The  heat  required  to  render  matter  luminous  in  its  three  states  of  aggregation  dillers  greatly. 
Thus  solids  are  sometimes  luminous  at  comparatively  low  temperatures,  as  phosphorus 
and  phosphoric  acids.  Usually,  however,  solids  re<iuire  a  temperature  of  600°  or  700'  F. 
to  render  them  luminous  in  the  dark,  and  must  be  heated  to  1000'  F.  before  their  luminos- 


3G4  COAL-GAS. 

ity  becomes  visible  in  daylight.  Liquids  require  about  the  same  temperature.  But  to  ren- 
der pases  luminous,  they  might  be  exposed  to  an  immensely  higher  temperature ;  even  the 
iiittMise  heat  generated  by  the  oxyhydrogen  blowpipe  scarcely  suffices  to  render  the  aciueous 
va[)or  produced  visibly  luminous,  although  solids,  such  as  lime,  emit  light  of  the  most  daz- 
zling splendor  when  thoy  are  heated  in  this  flame.  Hence  those  gases  and  vapors  only  can 
illuminate  which  produce,  or  deposit,  solid  or  liquid  matter  doi-ing  their  combustion.  This 
dependence  of  light  upon  the  production  of  solid  matter  is  strikingly  seen  in  the  case  of 
phosphorus,  which  when  burnt  in  chlorine  produces  a  light  scarcely  visible,  but  when  con- 
sumed in  air  or  oxygen  emits  light  of  intense  brilliancy.  In  the  former  case  the  vapor  of 
chloride  of  phosphorus  is  produced,  in  the  latter,  solid  phosphoric  acid. 

Several  gases  and  vapors  possess  this  property  of  depositing  solid  matter  during  com- 
bustion, but  a  few  of  the  combinations  of  carbon  and  hydrogen  are  the  only  ones  capable 
of  practical  application :  these  latter  compounds  evolve  duiing  combustion  only  the  same 
products  as  those  generated  in  the  respiratory  process  of  animals,  viz. :  carbonic  acid  and 
water.  The  solid  particles  of  carljon  which  they  deposit  in  the  interior  of  the  flame,  and 
which  are  the  source  of  light,  are  entirely  consumed  on  arriving  at  its  outer  boundary ; 
their  use  as  sources  of  artificial  light,  under  proper  regulations,  is  therefore  quite  compat- 
ible witli  the  most  stringent  sanitary  rules. 

The  constituents  of  purified  coal-gas  have  already  be(*n  divided  into  illuminating  and 
non-illuminating  gases ;  amongst  the  latter  will  be  found  light  carburcttcd  hydrogen,  which, 
altliongh  usually  regarded  as  an  illuminating  gas,  has  been  proved  by  the  experiments  of 
Frankland  to  produce,  under  ordinary  circumstances,  no  more  light  than  hydrogen  or  car- 
bonic oxide,  and  therefore  for  all  practical  purposes  it  must  be  regarded  as  entirely  desti- 
tute of  illuminating  power.  This  is  owing  chiefly  to  the  temperature  required  for  the  de- 
position of  its  carbon  being  higher  than  that  attained  in  an  ordinary  gas-burner ;  for  Frank- 
land  has  proved  that,  if  the  temperature  of  the  light  carburetted  hydrogen  flame  be  increased 
by  previously  heating  the  gas  and  air  nearly  to  redness,  then  the  flame  becomes  luminous 
to  a  considerable  degree.  It  is  not  improbable  that  when  gas  is  consumed  in  very  large 
burners  this  necessary  temperature  is  attained,  and  the  light  carburetted  hydrogen  con- 
triljutes  considerably  to  the  aggregate  illuminating  effect ;  a  view  which  is,  to  a  certain  ex- 
tent, confirmed  by  the  fact,  that  a  relatively  much  larger  amount  of  light  is  obtained  from 
coal-gas  when  the  latter  is  consumed  in  a  large  flame  than  when  it  is  allowed  to  burn  in  a 
small  flame. 

Omitting  light  carburetted  hydrogen  and  carbonic  oxide,  the  remaining  carboniferous 
constituents  of  coal-gas  yield,  during  combustion  from  suitable  burners,  an  amount  of 
light  directly  proportionate  to  the  quantity  of  carbon  which  they  contain  in  a  given 
volume. 

In  order  to  understand  the  nature  of  the  combustion  of  a  gas  flame,  it  is  necessary  to 
remember  that  the  flame  is  freely  permeable  to  the  air,  and  that,  according  to  the  well- 
known  laws  of  gaseous  mixture,  the  amount  of  air  which  mixes  with  the  ignited  gases  will 
be  increased,  fii-st,  by  an  increase  of  the  velocity  with  which  the  gas  issues  from  the  orifice 
of  the  burner;  and  secondly,  by  the  velocity  of  the  current  of  air  immediately  surrounding 
the  flame.  It  is  well  known  that  a  highly  luminiferous  gas  may  be  deprived  of  all  illumina- 
ting power  cither  by  being  made  to  issue  from  the  burner  with  great  velocity,  or  by  being 
burnt  in  a  very  rapid  current  of  air  produced  by  a  very  tall  glass  chimney. 

The  foregoing  considerations  indicate  the  conditions  best  adapted  for  obtaining  the  max- 
imum illuminating  effect  from  coal-gas.  The  chief  condition  is  the  supply  of  just  such  a 
volume  of  air  to  the  gas  flame  as  shall  prevent  any  particles  of  carbon  from  escaping  uncon- 
sumed.  Any  excess  of  air  over  this  quantity  nmst  diminish  the  number  of  particles  of  car- 
bon deposited  within  the  flame,  and  consequently  impair  the  illuminating  cfiect. 

Another  condition  is  the  attainment  of  the  highest  possible  temperature  within  the 
flame.  The  first  of  these  conditions  has  been  more  or  less  perfectly  obtained  in  the  difter- 
ent  ga.s-burners  now  in  use.  The  second  has  been  hitherto  almost  entirely  neglected :  the 
means  by  which  it  may  be  attained  will  be  discussed  after  the  burners  at  present  in  general 
use  have  been  described. 

The  chief  burners  now  in  use  are  the  bat's-wing,  fish-tail,  argand,  bude  argand,  "Win- 
field's  argand.  Guise's  argand,  and  Leslie's  argand. 

The  baVs-innrf  consists  of  a  fine  slit  in  an  iron  nipple,  giving  a  flat  fan-like  flame. 

The  Jish-tail  consists  of  a  similar  nipple  perforated  by  two  holes,  drilled  so  that  the  jets 
of  gas  are  inclined  towards  each  other  at  an  angle  of  aliout  ('>(■).  A  flat  film  of  flame  is 
thus  produced,  somewhat  resembling  the  tail  of  a  fish.  This  form  of  burner  is  especially 
adapted  for  the  consumption  of  cannel  and  other  highly  illuminating  gases. 

The  nrrjand  consists  of  a  hollow  annulus,  (see  fir/.  101,)  from  the  upper  surface  of  which 
the  gas  issues  through  a  number  of  small  apertuies,  which  are  made  to  vary  in  diameter 
from  ''30  of  an  inch  to  */f,o  of  an  inch,  according  to  the  richness  of  the  gas;  the  most  highly 
illuminating  gases  requiring  the  smallest  apertures.     The  distances  of  the  orifices  for  coal- 


COAL-GAS. 


365 


gas  should  be  '16  to  "18  inch,  and  for  rich  cannel  gas  "IS  inch.     If  the  argand  ring  has  ten 

orifices,  the  diameter  of  the  central  opening  should  be  =  Vio  of 

an  inch ;  if  25  orifices,  it  should  be  1  inch  for  coal  gas  ;  but  for  oil 

gas,  with  10  orifices,  the  central  opening  should  have  a  diainctur 

of  4  an  inch,  and  for  20  orifices,  1  inch.    The  pin  holes  should  )je 

of  equal  size,  otherwise  the  larger  ones  will  cause  smoke,  as  in 

an  argand  flame  with  an  uneven  wick. 

The  bude  burner  consists  of  2  or  3  concentric  argand  rings 
perforated  in  the  manner  just  described.  It  is  well  adapted  for 
producing  a  large  body  of  very  intense  light  with  a  comparatively 
moderate  consumption  of  gas. 

Winfield's  argand. — The  chief  distinction  between  this  and 
the  ordinary  argand  burner  consists  in  the  introduction  of  a  metallic 
button  above  the  annulus,  so  as  to  cause  the  internal  current  of  air 
to  impinge  against  the  flame.  A  peculiarity  in  the  shape  of  the 
glass  chimney,  as  seen  in  the  figure,  produces  the  same  effect  upon 
the  outer  current  of  air.     Sec  Jig.  162. 

Guise\s  argajid  contains  26  holas  in  a  ring,  the  inner  diameter 
of  which  is  '6  inch,  and  the  outer  diameter  1-9  inch.  Like  the 
Winfieid  burner,  it  has  a  metal  button  +  an  inch  in  diameter,  and 
1  inch  above  the  annulus.  The  glass  chimney,  Avhich  is  cylin- 
drical, is  2  inches  in  diameter,  and  6  inches  long. 

Leslie's  argand  consists,  as  is  seen  in  the  figure,  {fig.  1 64,)  of  a  series  of  fine  tubes  arranged 

let 


in  a  circle,  by  which  a  more  uniform  admixture  of  air  with  the  gas  is  effected.  A  suflicient 
current  of  air  for  all  these  argand  burners  can  only  be  oljtained  by  the  use  of  a  glass  chhn- 
ney,  the  rapidity  of  the  current  depending  upon  the  height  of  the  chimney.  In  the  Les- 
lie's argand  the  height  of  the  chimney  is  especially  adapted  to  the  amount  of  light  re- 
quired, and  in  order  to  consume  gas  economically,  this  point  must  be  attended  to  in  all 
argand  burners. 

The  following  experiments  made  with  different  burners,  by  three  eminent  experiment- 
ers, upon  the  gas  from  three  different  kinds  of  coal,  show  the  relative  values  of  these 
burners  for  the  gases  produced  from  the  chief  varieties  of  coal  used  for  the  manufac- 
ture of  gas  in  this  country. 


Table  I. — Results  of  Experiments  on 

Newcastle  Cannel  Gas, 

hg  Mr. 

A.   Wr 

ght. 

1  Foot 

1}  Foot 

2  Feet    |    ii  Feet        3  Feet 

3j  Feet 

4  Feet 

4}  Feel 

per  Hour. 

per  Hour. 

per  Hour,   per  Hour,   per  Hour. 

per  Hour. 

per  Hour. 

per  Hour. 

Scotch  Fish-tail,  No.  1 : — 

One  foot  :=  candles    -    - 

4-75 

502 

"         =  grains  of  sperm 

595-0 

602  0 

Scotch  Fish-tail,  No.  2  :— 

One  foot  =  candles    -    - 

505 

5-7T 

5-95 

5-S4 

5-53 

"        =  srrains  of  sperm 

6060 

090-0 

V14-0 

7000 

6G3-0 

Guise's  Argand:— 

One  font  =  candles    -    - 

. 

1-OS 

185 

812 

4  85 

4  95 

5-77 

C-74 

"        =  grains  of  sperm 

■     - 

129-0 

222-0 

374-0 

582-0 

594-0 

692-0 

808-0 

366 


COAL-GAS. 


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COAL-GAS. 


367 


Table  III.  contains  the  results  of  Mr.  Barlow's  experiments  on  gas  produced  from  a  mix- 
ture of  Pelton,  Felling,  and  Dean's  Primrose,  all  first-class  Newcastle  gas-coals,  largely  used 
in  London. 

The  burners  employed  in  these  experiments  were  the  following: — 

1st.  A  No.  3  fish-tail,  or  union  jet. 

2d.  A  No.  5  bat's-wing. 

3d.  A  common  argand,  with  15  large  holes  in  a  ring  So  inch  diameter,  and  a  cylin- 
drical chimney  glass  7  inclies  high. 

4th.  A  Platow's  registered  argand,  with  large  holes  in  a  ring,  '9  inch,  with  inside  and 
o'.Uside  cone,  and  cylindrical  chimney  glass  8'5  inches  high. 

5th.  A  Biznner's  patent  No.  3  argand,  with  28  medium-sized  holes  in  a  ring  "75  inch 
diameter,  and  cylindrical  chimney  glass  8 '65  inches  high. 

6th.  A  Winfield's  registered  argand,  with  58  medium-sized  holes  in  2  rings  of  29  holes 
in  each,  the  mean  diameter  being  1  inch,  with  deflecting  button  inside  and  gauge  below, 
bellied  chimney  glass  8  inches  high. 

7th.  A  Leslie's  patent  argand,  with  28  jets  in  a  ring  "95  inch  diameter,  and  chimney  glass 
3"o  inches  high. 

8th.  A  Guise's  registered  shado^vless  argand,  with  26  large  holes  in  a  ring  "85  inch 
diameter,  and  deflecting  button,  cylindrical  chimney  glass  6'1  inches  high,  and  glass  reflect- 
ing cone  to  outside  gallery. 

On  an  average  of  numerous  trials  the  annexed  results  were  obtained : — 

Table  IIL 


Burner. 

Rate  of  Consumption  per 

Value  of  Cubic  Foot  in 

Standard  Candles  per 

Hour  in  Cubic  Feet. 

Grains  of  Sperm. 

Cubic  Foot. 

No.  2 

4-9 

289-0 

2-4 

"     3 

5-5 

343-0 

2-85 

"     5 

5-0 

374-0 

3-11 

"     6 

6-5 

337-0 

2-8 

"     8 

5-5 

350-0 

2-91 

"     1 

6-5 

276-0 

2-3 

"    2 

5-0 

290-0 

2-41 

"     3 

5-5 

341-0 

2-84 

"    4 

5-5 

348-0 

2-9 

"     5 

5-5 

380-0 

3-16 

"    6 

5-5 

335-0 

2-79 

"    7 

4-1 

369.0 

3-07 

"    8 

5-5 

364-0 

3-03 

It  has  been  stated  that  one  of  the  conditions  necessary  for  the  pro- 
duction of  the  maximum  illuminating  power  from  a  gas  flame,  is  the 
attainment  of  the  highest  possible  temperature,  and  that  this  condition 
has  been  almost  entirely  neglected  in  the  burners  hitherto  in  use.  Dr. 
Frankland  has,  however,  proved,  by  some  hitherto  unpublished  experi- 
ments, that  this  condition  may  be  easily  secured  by  employing  the  waste 
heat  radiating  from  the  gas  flame,  for  heating  the  air  previous  to  its 
employment  for  the  combustion  of  the  gas ;  and  that  the  increased  tem- 
perature thus  obtained  has  the  effect  of  greatly  increasing  the  illuminat- 
ing power  of  a  given  volume  of  the  gas.  Fi(/.  105  shows  the  burner 
contrived  by  Dr.  Frankland  for  this  purpose,  a  is  a  common  argand 
burner,  or  better,  a  Leslie's  argand,  furnished  with  the  usual  gallery 
and  glass  chimney  b,  c ;  the  latter  must  be  4  to  6  inches  longer  than 
usual.  (Z  c?  is  a  circular  disc  of  plate  glass,  perforated  in  the  centre,  and 
fixed  upon  the  stem  of  the  burner  about  1^  inches  below  the  gallery  by 
the  collar  and  screw  e.  ff  is  a  second  glass  chimney  somewhat  conical, 
ground  at  its  lower  edge  so  as  to  rest  air-tight,  or  nearly  so,  upon  the 
plate  d  d ;  and  of  such  a  diameter  as  to  leave  an  annular  space  \  inch 
broad  between  the  two  cylinders  at  g  g.  The  cylinder  f  should  l)e  of 
such  a  length  as  to  reach  the  level  of  the  apex  of  tlie  flame.  The  action 
.  of  this  burner  will  now  be  sufficiently  evident.  When  lighted,  atmos- 
I)heric  air  can  only  reach  the  flame  by  pii.'^sing  duwnwaids  tlu-ough  the 
space  between  the  cylinders  yand  c ;  it  thus  comes  into  contact  with 
the  intensely  heated  walls  of  c,  and  has  its  temperature  raised  to  about 
500'  or  600^  before  it  reaches  the  gas  flame.  The  pa.ss!ige  of  this 
heated  air  over  the  upper  portion  of  the  argand  burner,  also  rai.ses  the 
temperature  of  the  gas  considerabl}'  before  it  issues  from  the  burner. 


165 


368 


COAL-GAS. 


Thus  tlie  gases  taking  part  in  the  combustion  arc  liiglily  heated  before  inflammation,  and 
the  temperature  of  the  flame  is>  consequently  elevated  in  a  corresponding  degree.  Experi- 
ments with  this  burner  prove  a  great  increase  in  light,  due  chiefly  to  the  higher  temperature 
of  the  radiating  particles  of  carbon  ;  but,  no  doubt,  partly  also  to  the  heat  being  suHieienllv 
high  to  cause  a  deposition  of  carbon  from  the  light  carburetted  hydrogen ;  thus  rendering 
this  latter  gas  a  contributor  to  the  total  ilhuninating  effect ;  whilst,  when  burnt  in  the  oidi- 
nary  manner,  it  merely  performs  the  functions  of  a  diluent.  The  following  are  the  results 
of  Dr.  Franklaud's  experiments  with  this  burner : 

Light  in  Sperm  Canilles,  each 
burnins  liO  grs.  pci'  Hour. 
13-U  candles. 
15-5       " 


I.  Argand  burner  without 

external  cylinder. 

II.  Same  burner  with  ex- 

ternal cylinder. 


Kate 

of  Consumption 

per  Hour, 
r  3-3  cubic  feet 

3-7 

1  4-2 
(2-1 

2-6 

2-7 

3-0 

3-3 

17-0 
13-0 

15-5 
16-7 
19-7 
21-7 


These  results  show  that  the  new  burner,  when  compared  with  the  ordinary  argand,  saves 
on  an  average  49  per  cent,  of  gas,  when  yielding  an  eijual  amount  of  light ;  and  also  that  it 
produces  a  gain  of  67  per  cent,  in  light  for  equal  consumptions. 

Faradnfs  roifilatinrf  hnriicr. — This  admirable  contrivance,  the  invention  of  Mr.  Fara- 
day, completely  removes  all  the  products  of  combustion,  and  prevents  their  admixture  with 
the  atmosphere  of  the  apartments  in  which  the  gas  is  consumed.  The  burner  consists  of 
an  ordinary  argand, y?*/.  ItJO,  a,  fitted  with  the  usual  gallery  and  chimney  b  b.     A  second 

wider  and  taller  cylinder,  c  c,  rests  upon  the 
outer  edge  of  the  gallery  which  closes  at  bot- 
tom the  annular  space,  d  d,  between  the  two 
glass  cylinders.  c  c  is  closed  at  top  with 
a  double  mica  cap  c.  f  is  the  tul:)c  convey- 
ing the  gas  to  the  argand ;  ff  <^  is  a  wider 
tube  1;^  inches  in  diameter,  communicating  at 
one  extremity  with  the  annular  space  between 
the  two  glass  cylinders,  and  at  the  other,  either 
with  a  flue  or  the  open  air.  The  products  of 
coml)ustion  from  the  gas  flame  are  thus  com- 
pelled to  take  the  direction  indicated  by  the 
arrows,  and  are  therefore  prevented  from  con- 
taminating the  air  of  the  apartment  in  which 
the  gas  is  consumed,  h  is  a  ground  glass  globe 
enclosing  the  whole  arrangement,  and  having 
only  an  opening  below  for  the  admission  of 
air  to  the  flame.  In  order  to  dispense  with 
the  descending  tube,  to  which  there  are  some 
objections,  Mr.  Rutter  has  constructed  a  ven- 
tilating burner  in  which  the  ordinary  glass 
chimney  is  made  to  terminate  in  a  metal  tube, 
through  which  the  products  of  combustion  are  conveyed  away.  Mr.  Dixon  has  also  con- 
structed a  modification  of  Faraday's  burner,  the  peculiaiity  of  which  consists  in  the  use  of 
a  separate  tul)e  bringing  air  to  the  flame  from  the  same  place,  outside  the  building,  to  which 
the  products  of  the  burner  arc  conveyed ;  this  contrivance  is  said  to  prevent  downward 
draughts  through  the  escape  pipe,  and  a  consequently  unsteady  flame.  Faraday's  burner 
is  in  use  at  Buckingham  Palace,  Windsor  Castle,  the  ■House  of  Lords,  and  in  many  public 
buildings. 

Ox  THE  Estimation  of  the  Value  of  Illuminating  Gas. 
There  are  two  methods  in  use  for  estimating  the  illuminating  value  of  gas,  viz. : — 
Lst.  The  photometric  method. 
2d.  Chemical  analysis. 

The  photometric  method  consists  in  comparing  the  intensity  of  the  light  emitted  by  a 
gas  flame,  consuming  a  known  volume  of  gas,  with  that  yielded  by  some  other  source  of 
light  taken  as  a  standard.  The  standard  eiii])loyed  is  usually  a  spermaceti  candle,  burning 
at  the  rate  of  120  grains  of  fii)erm  per  hour.  A  spermaceti  candle  of  six  to  tlie  pound 
usually  liuriis  at  a  somewhat  quicker  rate  than  this  ;  but  in  all  cases  the  consumption  of 
sperm  Ijy  the  candle  during  the  course  of  each  experiment  ought  to  be  carefully  ascertained 
by  weighing,  and  the  results  obtained  corrected  to  the  120-grain  standard.  Thus,  suppose 
that  during  an  experiment  the  consumption  of  sperm  was  at  the  rate  of  130  grains  per 


COAL-GAS.  MS 

hour,  and  that  the  gas  flame  being  tested  gave  a  light  equal  to  20  such  candles,  and  it  is  re- 
quired to  know  the  light  of  this  tlame  in  standard  120-grain  candles,  then — 

120  :   130  :  :  20  :  21-7; 
or,  20  candles  burning  at  the  rate  of  130  grains  per  hour,  are  equal  to  2r7  candles  burning 
at  the  rate  of  120  grains  per  hour. 

There  are  two  methods  of  estimating  the  comparative  intensity  of  the  light  of  the  gas 
and  candle  flames,  both  founded  upon  the  optical  law  that  the  intensity  of  light  diminishes 
in  the  inverse  ratio  of  the  square  of  the  distance  from  its  source.  Thus,  if  a  sheet  of  writ- 
ing paper  be  held  at  the  distance  of  one  foot  from  a  candle,  so  that  its  surface  is  perpen- 
dicular to  a  line  joining  the  centre  of  the  sheet  and  the  flame,  it  will  be  illuminated  with  a 
light  four  times  as  intense  as  that  which  would  iiill  upon  a  sheet  of  paper  held  in  the  same 
position  at  a  distance  of  2  feet;  whilst  at  a  distance  of  3  feet  the  light  would  have  but  '/»  of 
the  intensity  it  possessed  at  1  foot.  One  method  of  estimating  the  comparative  intensity  of 
the  gas  and  candle  flames,  consists  in  placing  the  two  lights  and  an  opaque  rod  nearly  in  a 
straight  line,  and  in  such  a  way  as  to  cause  each  light  to  project  a  shadow  of  the  rod  upon  a 
white  screen  placed  at  a  distance  of  about  1  foot  behind  the  rod.  The  two  shadows  must 
now  be  rendered  of  equal  intensity  by  moving  the  candle  either  nearer  to  the  rod  or  further 
from  it.  The  shadows  will  be  of  equal  intensity  when  the  light  falling  upon  the  white 
screen  from  both  sources  is  equal ;  and  if  now  the  respective  distances  of  the  candle  and 
gas  flame  from  the  screen  be  measured,  then  the  square  of  the  distance  of  the  gas  flame 
divided  by  the  square  of  the  distance  of  the  candle  will  give  the  illuminating  power  of  the 
gas  in  candles.  Thus,  if  ecjually  intense  shadows  fall  upon  the  screen  when  the  candle 
is  3  feet  distant  and  the  gas  flame  12  feet,  the  illuminating  power  of  the  gas  flame 
will  be — 

— -  = •  =16  candles. 

3-  9 

This  method  of  estimating  the  illuminating  power  of  a  gas  flame,  known  as  the  shadow 
test,  is  very  easy  of  execution,  and  would  appear  from  the  description  to  be  capable  of  yield- 
ing results  of  considerable  accuracy;  nevertheless,  an  unexpected  difficulty  arises  from  the 
great  difference  in  color  of  the  two  shadows ;  that  of  the  gas  being  of  a  bluish  brown,  whilst 
that  of  the  candle  is  of  a  yellow  brown  tinge.  This  difference  of  tint  renders  it  exceedingly 
difficult  for  the  observer  to  ascertain  when  the  two  shadows  possess  equal  intensity ;  and, 
consequently,  the  limits  of  error  attending  determinations  by  this  test  are  probably,  even 
in  the  hands  of  an  experienced  operator,  never  less  than  5  per  cent.,  and  frequently  even 
as  much  as  10  per  cent.  The  shadow  test  has,  therefore,  been  all  but  superseded  by  the 
Bunseii's  Photometer,  which  consists  of  a  graduated  metal  or  wooden  rod  about  8  or  10 
feet  long,  and  sufficiently  strong  to  be  inflexible.  At  one  extremity  of  this  rod  is  placed 
the  ga.8  flame,  and  at  the  opposite  end  the  standard  candle.  A  stand  which  slides  easily  along 
the  rod  supports  a  small  circular  paper  screen,  at  the  same  height  as  the  two  flames,  and  at 
right  angles  to  the  rod.  This  screen  consists  of  colorless,  moderately  tlun  writing  paper, 
saturated  with  a  solution  of  spermaceti  in  spirit  of  turpentine,  except  a  spot  in  the  centre, 
about  the  size  of  a  shilling,  which  is  to  be  left  untouched  by  the  solution.  The  spirit  of 
turpentine  soon  evaporates,  and  the  paper  is  now  ready  for  use.  Being  more  transparent  in 
the  portion  which  has  been  saturated  with  the  spermaceti  solution,  it  becomes  a  delicate  test 
of  e(iuality  of  light  when  placed  between  two  luminous  bodies ;  for  if  the  light  of  one  of  the 
bodies  impinge  with  greater  intensity  upon  one  side  of  the  screen  than  the  other  light  does 
upon  the  opposite  side,  the  difference  in  the  transparency  of  the  two  poitions  of  the  screen 
will  become  distinctly  visible ;  the  spot  in  the  centre  appearing  comparatively  opa(|ue  on  the 
less  illuminated  side.  When  the  screen  is  brought  into  such  a  position  between  the  two  sources 
of  light  as  to  render  the  central  spot  nearly  or  quite  invisible  on  both  sides,  the  illuminating 
effect  of  both  lights  at  that  point  may  be  regarded  as  equal ;  and  all  that  now  remains  to  be 
done  is  to  measure  the  respective  distances  of  the  candle  and  gas  from  the  screen,  and  di- 
vide the  square  of  the  distance  of  the  gas  by  the  square  of  that  of  the  candle :  the  quotient 
expresses  the  illuminating  power  of  the  gas  in  candles.  One  of  the  most  convenient  forms 
of  this  instrument  has  been  contrived  by  Mr.  Wright,  and  may  be  had  at  55  Millbank 
Street,  Westminster.     It  consists  of  the  following  parts : — 

1.  A  wooden  rod  exactly  100  inches  long  (Jig.  1G7)  from  the  centres  of  sockets  at  its 
ends  A  B. 

2.  An  upright  pillar  C. 

3.  A  candle  holder  d. 

4.  A  mahogany  slide  e,  having  a  metal  socket  F  on  its  top,  to  hold  the  circular  frame  o, 
and  a  small  pointer  in  its  front. 

5.  A  circular  metal  frame  o,  made  to  hold  a  prepared  paper. 

6.  A  blackened  conical  screen  ii,  dimini.-^hing  in  size  from  its  centre,  where  it  opens 
with  a  hinge  towards  its  ends,  with  two  holes  in  front. 

The  long  rod  is  graduated,  in  accordance  with  the  laws  of  distribution  of  light,  from  its 
Vol.  III.— 24 


370 


COAL-GAS. 


centre  each  way  into  squares  of  distances  in  divisions  numbered  respectively  1,  2,  3,  &c., 
to  36 ;  to  measure  smaller  differences  than  those  amounting  to  1  candle  in  value,  each 
major  division  to  9  is  subdivided  into  10  parts,  each,  of  course,  representing  '/lo  of  an  in- 
crement. From  thence  to  20  the  subdivisions  indicate  i-.  Beyond  that  point  no  subdivi- 
sions are  made,  because  the  major  divisions  become  so  small  that,  practically,  such  divisions 
would  be  useless. 

The  manner  of  fitting  the  apparatus  together  will  be  understood  by  reference  to  the 
annexed  sketch. 

167 


The  pillar  c  is  screwed  to  one  end  of  the  shelf,  and  an  experimental  meter  l  placed 
at  the  other.  This  latter  instrument  is  for  measuring  the  quantity  of  gas  passing  to  the 
burner,  and  indicating  the  rate  of  consumption  by  observations  of  one  minute,  which  is 
accomplished  by  the  construction  of  its  index  dial. 

This  dial  has  two  circles  upon  its  face,  with  a  pointer  to  each ;  the  outer  circle  divided 
into  four,  and  the  inner  into  six  parts ;  and  each  of  these  again  divided  into  tenths.  Every 
major  division  of  the  outer  circle  is  a  cubic  foot ;  and  every  major  division  of  the  inner 
circle  is  Voo  of  a  cubic  foot ;  so  that  the  major  divisions  on  the  inner  circle  each  bear  the 
same  proportion  to  a  cubic  foot  that  a  minute  does  to  an  hour.  If,  therefore,  the  number 
of  these  divisions  and  tenths  of  divisions,  which  the  hand  passes  over  in  a  minute,  is  ob- 
served, it  will  evidently  only  be  necessary  to  read  them  off  as  feet  and  tenths  of  a  foot  to 
obtain  the  hourly  rate  of  consumption. 

Thus,  suppose  the  pointer  passes  from  the  upper  figure  6  to  the  fifth  minor  division  be- 
yond the  figure  4,  it  would  read  off  as  4Vio  and  %oo  of  a  cubic  foot  in  Veo  of  an  hour. 
Multiplying  these  quantities  Vjy  60,  we  have  Veo  %oo  x  60  =  ^'""/eoo  =  4^  cubic  feet  and 
Voo  X  60  =  1 ;  so  that  4i  feet  and  1  hour  are  obtained  by  simply  reading  off  the  divisions 
which  had  been  passed  as  feet  and  tenths. 

A  pillar  J,  having  a  pressure  gauge  and  two  <?ocks  at  k,  one  with  a  micrometer  move- 
ment, screws  on  to  the  top  of  the  meter,  and  is  intended  for  receiving  burners  when  experi- 
menting. The  graduated  rod  is  supporte-d  in  an  exactly  horizontal  position  by  the  pillars 
c  and  J,  and  screwed  together  by  its  binding  screws. 

The  candle  socket  d  is  screwed  on  to  the  top  of  c,  and  the  mahogany  slide  c  pkced  on 
the  rod,  with  its  pointer  to  the  scale,  carrying  the  frame  G,  containing  a  prepared  paper, 
and  covered  by  the  cone  ii. 

The  prepared  paper  is  made  by  coating  white  blotting-paper  with  sperm,  so  as  to  render 
it  semi-transparent,  leaving  a  small  spot  in  the  centre  plain,  and  therefore  opaque.  See  G 
in  the  figure. 

All  that  now  remains  to  render  the  apparatus  ready  for  experimenting,  is  to  put  a  piece 
of  candle  into  the  socket,  and  con.sume  the  gas  through  a  proper  burner  over  the  meter, 
taking  care  that  the  centres  of  the  candle-flame^  paper,  and  gas  Jiame,  are  in  one  horizontal 
line,  and  adopting  the  precautions  previously  laid  down. 

Unfortunately,  the  determination  of  the  exact  point  of  equality  of  the  two  lights,  is  by 
no  means  easy,  even  after  considerable  practice ;  and  the  niaxiniuni  amount  of  error  to 
which  even  the  practised  operator  is  liable  in  such  estimations  of  illuminating  power,  can- 
not be  set  do^Ti  at  less  than  5  per  cent.  It  is  scarcely  necessary  to  add,  that  all  photometric 
experiments  must  be  conducted  in  an  apartment  from  which  all  light  from  other  sources  is 
excluded,  and  the  walls  of  which  are  rendered  as  absoihcnt  as  possible,  by  being  coated 
with  a  mixture  of  lampblack  and  size,  or  by  being  hung  with  black  lustreless  calico. 

Anahjtiral  Method  of  Estimatinf)  the  Value  of  Ulumiriatinr)  Gas. — Frankland  has 
shown  that  the  resources  of  chemical  analysis  place  in  om-  hands  a  method  for  the  determi- 
nation of  the  illuminating  value  of  gas  considerably  more  accurate  than  the  photometric 
processes  just  described,  although  the  execution  of  the  necessary  operations  requires  more 
skill,  and  is  usually  much  more  troublesome.  As  the  determination  of  the  illuminating 
power  of  a  sample  of  gas  by  the  analytical  method  necessitates  most  of  the  operations  re- 
quired for  the  i)erforniance  of  a  complete  analysis  of  coal-gas,  we  shall  here  include  in  our 
description  of  tlie  former  process  the  additional  details  necessary  for  the  latter. 


COAL-GAS. 


371 


1C8 


1.  Collection  of  the  Sample  of  Gas. — In  all  analytical  operations  upon  gases,  it  is  of 
the  utmost  importance  that  the  latter  should  be  preserved  from  all  admixture  witli  atmos- 
pheric air.  This  can  only  be  done,  either  by  collecting  the  samples  of  gas  over  mercury,  or 
by  enclosing  them  in  hermetically  sealed  tubes.  When  the  sample  of  gas  is  collected  at 
the  place  where  the  analysis  is  to  be  made,  the  former  plan  is  usually  most  convenient ;  but 
when  the  sample  has  to  be  obtained  from  a  locality  at  some  distance  from  the  operator's 
laboratory,  the  latter  plan  is  usudly  adopted.  To  collect  a  sample  of  gas  over  mercury, 
attach  one  end  of  a  piece  of  vulcanized  India-rubber  tube  to  the  gas-pipe,  and  insert  into 
the  other  extremity  a  piece  of  glass  tube  bent,  as  shown  at  a,  Jig.  168,  allow  the  gas  to 
stream  through  these  tubes  for  two  or  three  minutes,  and 
then  suddenly  plunge  the  open  extremity  of  the  glass 
tube  beneath  the  surface  of  the  mercury  in  the  trough 
c.  Then  fill  the  small  glass  jar  b  completely  with  mer- 
cury, taking  care  to  remove  all  air-bubbles  from  its  sides 
by  means  of  a  piece  of  iron  wire,  and  closing  its  mouth 
firmly  with  the  thumb,  invert  it  in  the  trough  c,  intro- 
ducing the  end  of  the  bent  tube  a  into  its  open  extrem- 
ity, in  such  a  way  as  to  bring  the  mouth  of  a  above  the 
level  of  the  surface  of  the  mercury  in  c.  The  gas  will 
then  flow  into  b,  until  the  level  of  the  mercury  in  b  is 
somewhat  lower  than  that  of  the  metal  in  the  trough. 
If  now,  the  tube  a  being  removed,  a  small  cup  be  filled  with  mercury  and  brought  beneath 
B,  the  latter  may  be  removed  from  the  trough,  and  will  be  thus  preserved  from  any  appre- 
ciable atmospheric  intermixture  for  several  months. 

To  collect  samples  of  gas  in  hermetically  sealed  tubes,  proceed  as  follows :  Take  a  piece 
of  glass  tube  about  f  of  an  inch  internal  diameter,  and  1  foot  long ;  draw  it  out  at  both 
ends  before  the  blowpipe,  as  shown  in  fig.  169  ;  attach  one  extremity  a,  fig.  lYO,  to  a  vul- 
canized India  rubber  tube,  communicating  with  a  source  of  the  gas,  and  the  opposite  ex- 
tremity B  to  a  similar  flexible  tube  about  three  feet  long,  and  which  is  allowed  to  hang 
down  perpendicularly  from  b.  After  the  gas  has  streamed  through  this  system  of  tubes  for 
about  three  minutes,  so  as  to  ensure  the  complete  expulsion  of  atmospheric  air,  the  flame 
of  a  mouth  blowpipe  is  directed  against  the  narrow  portion  of  the  glass  tube  at  c,  so  as  to 
fuse  it  off.  With  as  much  expedition  as  possible  the  same  operation  is  performed  at  the 
opposite  extremity  of  the  tube  d,  which  is  thus  hermetically  sealed,  and  assumes  the  appear- 
ance shown  in  Jig.  17  L 


169 


171 


> 


170 


The  gas  having  been  thus  carefully  collected,  the  necessary  analytical  operations  must 
be  conducted  over  mercury  in  a  small  wooden  pneumatic  trough,  with  plate  glass  sides,  the 
construction  of  which  is  shown  in  fg.  172.  a  is  a  piece  of  hard  well-seasoned  wood,  12 
inches  long  and  3  inches  broad,  hollowed  out,  as  shown  in  the  figure ;  the  cavity  is  8J 
inches  long,  1 J  inches  broad,  and  If  inches  deep.  The  bottom  of  this  cavity  is  roimdcd, 
with  the  exception  of  a  portion  at  one  end,  where  a  surface,  1  incli  broad,  and  1  \  inches 
long,  is  made  perfectly  flat,  a  piece  of  vulcanized  India-ruljber,  Vio  of  an  inch  thick,  beiii"- 
firmly  cemented  upon  it.  Two  end  pieces  n  n,  f  of  an  inch  thick,  3J  inches  broad,  and  .5 
inches  high,  are  fixed  to  the  block  a  ;  these  serve  below  a.s  .supports  for  a,  and  above  as  the 
ends  of  a  wider  trough,  which  is  formed  by  the  pieces  of  plate  glas.s  c  c,  cemented  into  a 
and  B  B.     The  glass  plates  co  are  lOJ  inches  long,  and  4  J  inches  high  ;  they  are  slightly 


372 


COAL-GAS. 


inclined,  ?o  that  their  lower  edges  are  about  2f  inches,  and  their  upper  edges  2|  inches 
apart.  This  trough  stands  upon  a  wooden  slab  d  d,  upon  which  it  is  held  in  its  place 
bv  two  strips  of  wood  e  e.  An  upright  column  f,  which  is  screwed  into  d,  carries  the 
inclined  stand  g,  which  serves  to  support  the  eudiometer  during  the  transference  of  gas. 
h  is  a  circular  inclined  slot  in  b,  which  allows  of  the  convenient  inclination  of  the  eudiome- 
ter in  the  stand  g.  i  is  an  indentation  in  which  the  lower  end  of  the  eudiometer  rests,  so 
as  to  prevent  its  falling  into  the  deeper  portion  of  the  trough  a.  When  in  use,  the  trough 
is  filled  with  quicksilver  to  within  an  inch  of  the  upper  edge  of  the  glass  plates  c  c,  about 
SO  to  35  lbs.  of  the  metal  being  necessary  for  this  purpose. 

The  eudiometers,  or  measuring  tubes,  should  be  accurately  calibrated  and  graduated  into 
cubic  inches  and  tenths  of  a  cubic  inch,  the  tenths  being  subdivided  by  the  eye  into  hun- 
dredths, when  the  volume  of  gas  is  read  off;  this  latter  division  is  readily  attained  by  a 
little  practice.  At  each  determination  of  volume,  it  is  necessary  that  the  gas  should  either 
be  perfectly  dry,  or  quite  saturated  with  moisture.  The  first  condition  is  attained  by  plac- 
ing in  the  gas,  for  half  an  hour,  a  small  ball  of  fused  chloride  of  calcium,  attached  to  a  pla- 
tinum wire  ;*  the  second  condition,  by  introducing  a  minute  drop  of  water  into  the  head 
of  the  eudiometer,  before  filling  it  with  quicksilver.  The  determinations  of  volume  must 
either  be  made  when  the  mercury  is  at  the  same  level  inside  and  outside  the  eudiometer, 
or,  as  is  more  frequently  done,  the  difference  of  level  must  be  accurately  measured  and 
allowed  for  in  the  subsequent  reduction  to  a  standard  pressure.  The  height  of  the  barome- 
ter and  the  temperature  of  the  surrounding  atmosphere  must  also  be  observed  each  time 
the  volume  of  gas  is  measured,  and  proper  corrections  made  for  pressure,  temperature,  and 
also  the  tension  of  aqueous  vapor,  if  the  gas  be  moist.  As  tables  and  rules  for  these  cor- 
rections are  given  in  most  treatises  on  chemistry,  they  need  not  be  repeated  here. 

These  troublesome  corrections  and  calculations  can  be  avoided,  by  employing  an  instru- 
ment lately  invented  by  Dr.  Frankland  and  Mr.  Ward,  and  which  not  only  does  away  with 
the  necessity  for  a  room  devoted  exclusively  to  gaseous  manipulations,  but  greatly  shortens 
and  simplifies  the  whole  operation.  This  instrument,  which  is  represented  by/r/.  173,  con- 
sists of  the  tripod  a,  furnished  with  the  usual  levelling  screws,  and  carrying  the  vertical 
pillar  B  B,  to  which  is  attached,  on  the  one  side,  the  movable  mercury  trough  c,  with  its 
rack  and  pinion  a  a,  and  on  the  other,  the  glass  cylinder  d  d,  with  its  contents.  This  cylin- 
der is  36  inches  long,  and  4  inches  internal  diameter  ;  its  lower  extremity  is  firmly  cemented 
into  an  iron  collar  r,  the  under  surface  of  which  can  be  screwed  perfectly  water-tight  upon 
the  bracket-plate  d  by  the  interposition  of  a  vulcanized  caoutchouc  ring.  The  circular  iron 
plate  d  is  perforated  with  three  apertures,  into  which  the  caps  e,  e,  e,  are  screwed,  and 


*  Those  balls,  wliich  should  bo  of  tho  size  of  a  lar^e  pea,  are  required  constantly  in  operations  upon 
pases:  they  are  readilv  prepared,  when  the  substance  of  which  they  arc  formed  is  fusible  by  heat,  as 
chloride  of  calcium  or  caustic  potash,  by  meltins  these  materials  in  a  crucible  and  then  pouring  them 
into  a  small  bullet-mould  in  which  the  curved  end  of  a  platinum  wire  has  been  placed ;  when  quite  cold 
tho  ball  attached  to  the  wire  is  readilv  removed  from  the  mould.  Coke  bullets  are  made  by  fillinR  the 
mould  containinc  the  platinum  wire  with  a  mixture  of  two  parts  of  coke  and  one  of  coal,  both  tmely 
powdered,  and  then  exposing  the  mould  and  its  contents  to  a  heat  gradually  increased  to  redness,  for  a 
quarter  of  an  hour. 


COAL-GAS. 


373 


which  communicate  below  the  plate  with  the  t  piece  e  e.  This  latter  is  furnished  with  a 
double-way  cock  /,  and  a  single-way  cock  g,  by  means  of  which  the  tubes  cemented  into 
the  sockets  e,  e,  e,  can  be  made  to  communicate  with  each  other,  or  with  the  exit  pipe  h  at 
pleasure. 

F,  G,  H,  are  three  glass  tubes,  which  are  firmly  cemented  into  the  caps  e,  e,  e.  f  and  h 
are  each  from  15  to  20  millimetres  internal  diameter,  and  are  selected  of  as  nearly  the  same 
bore  as  possible,  to  avoid  a  difference  of  capillary  action.  The  tube  g  is  somewhat  wider, 
and  may  be  continued  to  any  convenient  height  above  the  cylinder,  h  is  accurately  gradu- 
ated with  a  millimetre  scale,  and  is  furnished  at  top  with  a  small  funnel  «,  into  the  neck  of 
which  a  glass  stopper,  about  2  millimetres  in  diameter,  is  carefully  ground.  The  tube  f  ter- 
minates at  its  upper  extremity  in  the  capillary  tube  k,  which  is  carefully  cemented  into  the 
small  steel  stopcock  I.  f  has  also 
fused  into  it  at  m,  two  platinum 
wires,  for  the  passage  of  the  elec- 
tric spark.  After  this  tube  has 
been  firmly  cemented  into  the  cap 
e,  its  internal  volume  is  accurately 
divided  into  10  perfectly  equal  parts, 
which  is  effected  without  difficulty 
by  first  filling  it  with  mercury  from 
the  supply  tube  g,  up  to  its  junc- 
tion with  the  capillary  attachment, 
and  then  allowing  the  mercury  to 
run  off  through  the  nozzle  h  until 
the  highest  point  of  its  convex  sur- 
face stands  at  the  division  10,  pre- 
viously made  so  as  exactly  to  coin- 
cide with  the  zero  of  the  millimetre 
scale  on  h  ;  the  weight  of  the  mer- 
cury thus  run  off  is  carefully  deter- 
mined, and  the  tube  is  again  filled 
as  before,  and  divided  into  10  equal 
parts,  by  allowing  the  mercury  to 
run  off  in  successive  tenths  of  the 
entire  weight,  and  marking  the 
height  of  the  convexity  after  each 
abstraction  of  metal.  By  using  the 
proper  precautions  with  regard  to 
temperature,  &c.,  an  exceedingly 
accurate  calibration  can,  in  this  way,s 
be  accomplished. 

The  absorption  tube  I  is  sup- 
ported by  the  clamp  »i,  and  con- 
nected with  the  capillary  tube  k,  by 
the  stopcock  and  junction  piece  / 1\ 
p,  as  shown  in  the  figure.  When 
the  instrument  is  thus  far  complete, 
it  is  requisite  to  ascertain  the  height 
of  each  of  the  nine  upper  divisions  on  tlie  tube,  above  the  lowest  or  tenth  division.  This 
is  very  accurately  effected  in  a  few  minutes  by  carefully  levelling  the  instrument,  filling  the 
tube  G  with  mercury,  opening  the  cock  /,  and  the  stoppered  funnel  i,  and  placing  the  cock 
f  in  such  a  position  as  to  cause  the  tubes  f  ii  to  communicate  with  the  supply  tube  G.  On 
now  slightly  turning  the  cock  r/,  the  mercury  will  slowly  rise  in  each  of  the  tubes  f  and  ii ; 
when  its  convex  surface  exactly  coincides  with  the  ninth  division  on  f,  the  influx  of  metal 
is  stopped,  and  its  height  in  Ji  accurately  observed  ;  as  the  tenth  division  on  f  corresponds 
with  the  zero  of  the  scale  upon  ii,  it  is  obvious  that  the  number  thus  read  off  is  the  height 
of  the  ninth  division  above  that  zero  point.  A  similar  observation  for  each  of  the  other 
divisions  upon  f  completes  the  instrument* 

Before  using  the  apparatus,  the  large  cylinder  D  D  is  filled  with  water,  and  the  internal 
walls  of  the  tubes  f  and  ii  are,  once  for  all,  moistened  with  distilled  water,  by  tlie  introduc- 
tion of  a  few  drops  into  each,  through  the  stopcock  /,  and  the  stoppered  funnel  /.  The 
three  tubes  being  then  placed  in  communication  with  each  other,  mercury  is  poured  into  g 
until  it  rises  into  the  cup  i,  the  stopper  of  which  is  then  firmly  closed.  When  the  mercury 
begins  to  flow  from  I,  that  cock  is  also  closed.  The  tubes  f  and  ii  are  now  apparently  filled 
with  mercury,  but  a  minute  and  imperceptible  film  of  air  still  exists  between  the  metal  and 


*  This  instnimpnt  may  be  obtained  from  Mr.  Oertling,  philosophical  instruincnt-niaker,  Store  Street 
Tottenham  Court  Itoad. 


374 


COAL-GAS. 


glass ;  this  is  effectually  got  rid  of  by  connecting  f  and  n  with  the  exit  tube  h,  and  allow- 
iu"  the  mercury  to  flow  out,  until  a  vacuum  of  several  inches  in  length  has  been  produced 
ill  both  tubes  ;  on  allowing  the  instrument  to  remain  thus  for  an  liour,  the  whole  of  the  fihn 
of  air  above  mentioned  will  diffuse  itself  into  the  vacuum,  to  be  filled  up  from  the  supply 
tube  G.  These  bubbles  are  of  course  easily  expelled  on  momentarily  opening  the  cock  I 
and  the  stopper  i  whilst  G  is  full  of  mercury.  The  absorption  tube  i  being  then  filled  with 
quicksilver,  and  attached  to  I  by  the  screw  clamp,  the  instrument  is  ready  for  use. 

In  illustration  of  the  manner  of  using  the  apparatus,  a  complete  description  of  an 
analysis  of  coal-gas  by  this  instrument  will  be  given  below. 

For  the  analysis  of  purified  coal-gas  by  means  of  the  mercury  trough  and  eudiometer, 
the  following  ojjcrations  are  necessary  : — 

I.  Estimation  of  Carbonic  Acid. 
A  few  cubic  inches  of  the  gas  are  introduced  into  a  short  eudiometer,  moistened  as 
above  described  ;  the  volume  is  accurately  noted,  with  the  pioper  corrections,  and  a  bullet 
of  caustic  potash  is  then  passed  up  through  the  mercury  into  the  gas  :  it  is  allowed  to  remain 
for  at  least  one  hour ;  the  volume  of  the  gas,  being  again  ascertained  and  subtracted  from 
the  first  volume,  gives  the  amount  of  carbonic  acid  which  has  been  absorbed  by  the  potash. 

II.  Estimation  of  Oxygkn. 
This  fas  can  be  very  accurately  estimated  by  Liebig's  method,  which  depends  upon  the 
rapid  absorption  of  oxygen  by  an  alkaline  solution  of  pyrogallic  acid.  To  apply  this  solu- 
tion, a  small  test  tube  is  filled  with  quicksilver,  and  inverted  in  the  mercury  trough  ;  a  few 
drops  of  a  saturated  solution  of  pyrogallic  acid  in  water  are  thrown  up  into  this  tube  by 
means  of  a  pipette,  and  then  a  similar  quantity  of  a  strong  solution  of  potash  ;  a  coke  bul- 
let attached  to  a  platinum  wire  is  introduced  into  this  liquid,  and  allowed  to  saturate  itself; 
it  is  then  withdrawn,  and  conveyed  carefully  below  the  surface  of  the  mercury  into  the 
eudiometer  containing  the  residual  gas  of  experiment  No.  1  ;  every  trace  of  oxygen  wJil  be 
absorbed  in  a  few  minutes,  when  the  bullet  must  be  removed,  and  the  volume  being  again 
measured,  the  diminution  from  the  last  reading  will  represent  the  amount  of  oxygen  origi- 
nally present  in  the  gas.  It  is  essential  that  the  coke  bullet,  after  saturation  with  the  alka- 
line'solution  of  pyrogallic  acid,  should  not  come  in  contact  with  the  air  before  its  introduc- 
tion into  the  gas. 

III.   Estimation  of  the  Luminiferous  Constituents. 
Various  methods  have  been  employed  for  the  estimation  of  the  so-called  olefiant  gas 
(luminiferous  constituents)  contained  in  coal-gas.      The  one  which  has  been  most  generally 
employed,  depends  upon  the  property  which  is  possessed  by  olefiant  gas,  and  most  hydro- 
carbons, of  combining  with  chlorine,  and  condensing  to  an  oily  liquid  :  hydrogen  and  light 
carburetted  hydrogen  are  both  acted  upon  in  a  similar  manner  when  a  ray  even  of  diffused 
lif'ht  is  allowed  to  have  access  to  the  mixture  ;  but  the  tondensation  of  the  olefiant  gas  and 
hydrocarbons  takes  place  in  perfect  darkness,  and  advantage  is  therefore  taken  of  this  cir- 
cumstance to  observe  the  amount  of  condensation  which  takes  place  when  the  mixture  is 
excluded  from  liglit.     The  volume,  which  disappears  during  this  action  of  the  chlorine,  is 
regarded  as  indicating  the  quantity  of  olefiant  gas  present  in  the  mixture.     There  are  many 
sources  of  error  inseparably  connected  with  this  method  of  operating,  which  render  the 
results  unworthy  of  the  slightest  confidence  ;  the  same  remark  applies  also  to  the  employ- 
ment of  bromine  in  the  place  of  chlorine  ;  in  addition  to  the  circumstance  that  these  deter- 
minations must  be  made  over  water,  which  allows  a  constant  diffusion  of  atmospheric  air 
into  the  gas,  and  vice  versa,  there  is  also  formed  in  each  case  a  volatile  liquid,  the  tension 
of  the  vapor  of  which  increases  the  volume  of  the  residual  gas ;  and  this  increase  admits 
of  neither  calculation  nor  determination.     The  only  material  l)y  which  the  estimation  of  the 
luminiferous  constituents  can  be  accurately  effected  is  anhj-drous  sulphuric  acid,  which  im- 
mediately condenses  the  luminiferous  constituents  of  coal-gas,  but  has  no  action  upon  the 
other  ingredients,  even  when  exposed  to  sunlight.     The  estimation  is  conducted  as  follows : 
A  coke  bullet  prepared  as  described  above,  and  attached  to  a  platinum  wire,  being  rendered 
thoroughly  dry  by  slightly  heating  it,  for  a  few  minutes,  is  quickly  immersed  in  a  saturated 
solution  of  anhydrous  sulphuric  acid,  in  Nordhausen  sulphuric  acid,  and  allowed  to  remain 
in  the  liqmd  for  one  minute  ;   it  is  then  withdrawn,  leaving  as  little  superfluous  acid  adher- 
ing to  it  as  possible,  quickly  plunged  beneath  the  quicksilver  in  tlie  trough,  and  introduced 
in?o  the  same  portion  of  dry  gas,  from  which  the  carbonic  acid  and  oxygen  have  been  with- 
drawn by  experiments  I.  and  II.  ;   here  it  is  allowed  to  remain  for  about  two  hours,  in  order 
to  ensure  the  complete  absorption  of  every  trace  of  hydrocarbons.      The  residual  volume 
of  gas  cannot,  however,  yet  be  determined,  owing  to  the  presence  of  some  sulphurous  acid 
derived  from  the  decomposition  of  a  portion  of  the  sulphuric  acid:   tliis  is  absorbed  in  a 
few  minutes  by  the  introduction  of  a  moist  bullet  of  peroxide  of  manganese,  which  is 
readily  made  by  converting  powdered  peroxide  of  manganese  into  a  stiff  paste  with  water, 
rolling  it  into  the  shape  of  a  small  bullet,  and  then  inserting  a  bent  platinum  wire,  in  such 


COAL-GAS.  375 

a  manner  as  to  prevent  its  being  readily  drawn  out ;  the  ball  should  then  be  put  in  a  warm 
place,  and  allowed  slowly  to  dry,  it  will  then  become  hard,  and  possess  considerable  cohe- 
sion, even  after  being  moistened  with  a  drop  of  water,  previous  to  its  introduction  into  the 
gas.  After  half  an  hour,  the  bullet  of  peroxide  of  manganese  may  be  withdrawn,  and  rc- 
phiced  by  one  of  caustic  potash,  to  remove  the  watery  vapor  introduced  with  the  previous 
one ;  at  the  end  of  another  half  hour,  this  bullet  may  be  removed,  and  the  volume  of  the 
gas  at  once  read  off.  The  diflerence  between  this  and  the  previous  reading,  gives  the 
volume  of  the  luminiferous  constituents  contained  in  the  gas.  This  method  is  very  accu- 
rate ;  in  two  syial.vses  of  the  same  gas,  the  percentage  of  luminferous  constituents  seldom 
varies  more  than  O'l  or  0-2  per  cent. 

IV.   Estimation  of  the  Nox-Luminiferocs  Constituents. 

These  are  light  carburetted  hydrogen,  hydrogen,  carbonic  oxide,  and  nitrogen.  The 
percentages  of  these  gases  are  ascertained  in  a  graduated  eudiometer,  about  2  feet  in  length, 
and  I  of  an  inch  internal  diameter;  the  thickness  of  the  glass  being  not  more  than  Vio  of 
an  inch.  This  eudiometer  is  furnished  at  its  closed  end  with  two  platinum  wires,  fused  into 
the  glass,  for  the  transmission  of  the  electric  spark.  A  drop  of  water,  about  the  size  of  a 
pin's  head,  is  introduced  into  the  upper  part  of  the  eudiometer  before  it  is  filled  with  mer- 
cury and  inverted  into  the  mercurial  trough  :  thfs  small  quantity  of  water  serves  to  saturate 
with  aqueous  vapor  the  gases  subsequently  introduced.  About  a  cubic  inch  of  the  residual 
gas  from  the  last  determination  is  passed  into  the  eudiometer,  and  its  volume  accurately  read 
off;  about  4  cubic  inches  of  pure  oxygen  are  now  introduced,  and  the  volume  (moist)  again 
determined.  The  oxygen  is  best  prepared  at  the  moment  when  it  is  wanted,  by  heating 
over  a  spirit  or  gas  flame  a  little  chlorate  of  potash,  in  a  very  small  glass  retort,  allowing 
of  course  sufficient  time  for  every  trace  of  atmospheric  air  to  be  expelled  from  the  retort 
before  passing  the  gas  into  the  eudiometer.  The  open  end  of  the  eudiometer  must  now  be 
pressed  firmly  upon  the  thick  piece  of  india-rubber  placed  at  the  bottom  of  the  trough,  and 
an  electric  spark  passed  through  the  mixture  ;  if  the  above  proi)ortions  have  been  observed 
the  explosion  will  be  but  slight,  which  is  essential  if  nitrogen  be  present  in  the  gas,  as  this 
element  will  otherwise  be  partially  converted  into  nitric  acid,  and  thus  vitiate  the  results. 
By  using  a  large  excess  of  oxygen,  all  danger  of  the  bursting  of  the  eudiometer  by  the 
force  of  the  explosion  is  also  avoided.  Tlie  volume  after  explosion  being  again  determined, 
a  bullet  of  caustic  potash  is  introduced  into  the  gas,  and  allowed  to  remain  so  long  as  any 
diminution  of  volume  takes  place  ;  this  bullet  absorbs  the  carbonic  acid  that  has  been  pro- 
duced by  the  combustion  of  the  light  carburetted  hydrogen  and  carbonic  oxide,  and  also 
renders  the  residual  gas  perfectly  dry  ;  the  volume  read  off  after  this  absorption,  when  de- 
ducted from  the  previous  reading,  gives  the  volume  of  carbonic  acid  generated  by  the  com- 
bustion of  the  gas. 

The  residual  gas  now  contains  only  nitrogen  and  the  excess  of  oxygen  employed.  The 
former  is  determined  by  first  ascertaining  the  amount  of  oxygen  present,  and  then  deduct- 
ing that  number  from  the  volume  of  both  gases  ;  for  this  purpose  a  quantity  of  dry  hydro- 
gen, at  least  three  times  as  great  as  the  residual  gas,  is  introduced,  and  the  volume  of  the 
mixture  determined  ;  the  explosion  is  then  made  as  before,  and  the  volume  (moist)  again 
recorded  :  one-third  of  the  contraction  caused  by  this  explosion  represents  the  volume  of 
0X3'gen,  and  this  deducted  from  the  volume  of  residual  gas,  after  absorption  of  carbonic 
acid,  gives  the  amount  of  nitrogen. 

The  behavior  of  the  other  three  non-luminous  gases  on  explosion  with  oxygen  enables 
us  readily  to  find  their  respective  amounts  by  three  simple  equations,  founded  upon  the 
quantity  of  oxygen  consumed,  and  the  amount  of  carbonic  acid  generated  by  the  three 
gases  in  question.  Hydrogen  consumes  half  its  own  volume  of  oxygen,  and  generates  no 
carbonic  acid  ;  light  carburetted  hydrogen  consumes  twice  its  volume  of  oxygen,  and  gen- 
erates its  own  volume  of  carbonic  acid  ;  whilst  carbonic  oxide  consumes  half  its  volume  of 
oxygen,  and  generates  its  own  volume  of  carbonic  acid.  If,  therefore,  we  represent  the 
volume  of  the  mixed  gases  by  A,  the  amount  of  oxygen  consumed  by  B,  and  the  quantity 
of  carbonic  acid  generated  by  C,  and  further,  the  volumes  of  hydrogen,  light  carl)uretted 
hydrogen,  and  carbonic  oxide  respectively  by  x,  y,  and  z,  we  have  the  following  equations : 

X  -I-  y  4-  z  =r  A 

y-l-z  =  C 

From  which  the  following  values  for  x,  y,  and  z  are  derived  : — 

x  =  A  — C 
2B  — A 

y 


z  =  C 


3 

2B  — A 


876  •  COAL-GAS. 

V.   Estimation  of  the  Value  of  the  Lcminiferous  Constituents. 

We  have  now  given  methods  for  ascertaining  the  respective  quantities  of  all  the  ingre- 
dients contained  in  any  specimen  of  coal-gas,  but  the  results  of  the  above  analytical  opera- 
tions at!brd  us  no  clue  to  its  illuminating  power.  They  give  us,  it  is  true,  the  amount  of 
illuminating  hydrocarbons  contained  in  a  given  volume  of  the  gas,  but  it  will  be  evident, 
from  what  has  already  been  said  respecting  the  luminifcrous  powers  of  these  hydrocarbons, 
that  the  greater  the  amount  of  carbon  contained  in  a  given  volume,  the  greater  will  be  the 
([Uantity  of  light  produced  on  their  combustion  ;  and  therefore,  as  the  number  of  volumes 
of  carbon  vapor  contained  in  one  volume  of  the  mixed  constituents,  condensible  by  anhy- 
drous sulphuric  acid,  has  been  found  to  vary  from  2 '54  to  4"oG  volumes,  it  is  clear  tliat  this 
amount  of  carbon  vapor  nuist  be  accurately  determined  for  each  specimen  of  gas,  if  we  wish 
to  ascertain  the  value  of  that  gas  as  an  illuminating  agent.  Fortunately  this  is  easily 
eifevtcd ;  for  if  we  ascertain  the  amount  of  carbonic  acid  generated  by  100  volumes  of  the 
gas  in  its  original  conditicm,  knowing  from  the  preceding  analytical  processes  the  percentage 
of  illuminating  hydrocarbons,  and  also  the  amount  of  carbonic  acid  generated  by  the  non- 
luminiferous  gases,  we  have  all  the  data  for  calculating  the  illuminating  value  of  the  gas. 
For  this  purpose  a  known  volume  of  the  original  gas  (about  one  cubic  inch)  is  introduced 
into  the  explosion  eudiometer,  and  mixed  with  about  five  times  its  volume  of  oxygen,  the 
electric  spark  is  passed,  and  the  volume  of  carbonic  acid  generated  by  the  explosion  ascer- 
tained as  above  directed.  If  we  now  designate  the  percentage  of  hydrocarbons  absorbed 
by  anhydrous  sulphuric  acid  by  A,  the  volume  of  carbonic  acid  generated  by  100  volumes 
of  the  original  gas  by  B,  the  carbonic  acid  formed  by  the  combustion  of  the  non-luminous 
constituents  remaining  after  the  absorption  of  hydrocarbons  from  the  above  quantity  of 
original  gas  by  C,  and  the  volume  of  carbonic  acid  generated  by  the  combustion  of  the 
lumiiiiferous  compounds  (hydrocarbons)  by  x,  we  have  the  following  equation : — 

x  =  B  — C 

and  therefore  the  amount  of  carbonic  acid  generated  by  one  volume  of  the  hydrocarbons  is  * 
represented  by 

B  — C 
A 

But  as  one  volume  of  carbon  vapor  generates  one  volume  of  carbonic  acid,  this  formula 
also  expresses  the  quantity  of  carbon  vapor  in  one  volume  of  the  illuminating  constituents. 
For  the  purpose  of  comparison,  however,  it  is  more  convenient  to  represent  the  value  of 
these  hydrocarbons  in  their  equivalent  volume  of  olefiant  gas,  one  volume  of  which  con- 
tains two  volumes  of  carbon  vapor ;  for  this  purpose  the  last  expression  need  only  be 
changed  to 

B  — C 
2  A 

Thus,  if  a  sample  of  gas  contain  10  per  cent,  of  hydrocarbons,  of  which  one  volume 
contains  three  volumes  of  carbon  vapor,  the  quantity  of  olefiant  gas  to  which  this  10  per 
cent,  is  equivalent,  will  be  15. 

By  the  application  of  this  method  we  obtain  an  exact  chemical  standard  of  comparison 
for  the  illuminating  value  of  all  descriptions  of  gas  ;  and  by  a  comparison  of  the  arbitrary 
numbers  thus  obtained,  with  the  practical  results  yielded  by  the  same  gases  when  tested  by 
the  photometer,  much  valuaV)le  and  useful  information  is  gained. 

Analysis  of  Coal-Gas  with  Frankland  and  Ward's  Apparatus. — Introduce  a  few  cubic 
inches  of  the  gas  into  the  tube  i,  frj.  173,  and  transfer  it  for  measurement  into  f,  by  open- 
ing the  cocks  II'  and  placing  the  tube  f  in  communication  with  the  exit  pipe  /*,  the  trans- 
ference being  assisted,  if  needful,  by  elevating  the  trough  c.  When  the  gas,  followed  by  a 
few  drops  of  mercury,  has  passed  completely  into  f,  the  cock  /  is  shut,  and  /  turned,  so  as 
to  connect  f  and  ii  with  h.  Mercury  is  allowed  to  flow  out  until  a  vacuum  of  two  or  three 
inches  in  length  is  formed  in  ii,  and  the  metal  in  f  is  just  below  one  of  the  divisions  ;  the 
cock  /  is  then  reversed,  and  mercury  very  gradually  admitted  from  o,  until  the  highest 
point  in  f  exactly  corresponds  with  one  of  the  divisions  upon  that  tube ;  we  will  assume  it 
to  be  the  sixth  division.  This  adjustment  of  mercury  and  the  subsequent  readings  can  be 
very  accurately  made  by  means  of  a  small  horizontal  telescope  placed  at  a  distance  of  about 
six  feet  from  the  cylinder,  and  sliding  upon  a  vertical  rod.  The  height  of  the  mercury  in  ii 
must  now  be  accurately  determined,  and  if  from  the  number  thus  read  off,  the  height  of  the 
sixth  division  above  the  zero  of  the  scale  on  ii  be  deducted,  the  remainder  will  express  the 
true  volume  of  the  gas.  As  the  temperature  is  maintained  constant  during  the  entire  analy- 
sis, no  correction  on  that  score  has  to  be  made  ;  the  atmospheric  pressure  being  altogether 
excluded  from  exerting  any  influence  iipon  the  volumes  or  pressures,  no  barometrical  ol)ser- 
vations  are  requisite ;  and  as  the  tension  of  aqueous  vapor  in  f  is  exactly  balanced  by  that 
in  II,  the  instrument  is  in  this  respect  also  self-correcting.      Two^r  three  drops  of  a  strong 


COAL-GAS. 


377 


solution  of  caustic  potash  are  now  introduced  into  i  by  means  of  a  bent  pipette,  and  mer- 
cury  being  allowed  to  flow  into  f  and  n  Vjy  cpening  tlie  cock  g,  the  gas  returns  into  i 
tln-ougli  II ',  and  there  coming  into  contact  with  an  extensive  surface  of  caustic  potash  solu- 
tion, any  carbonic  acid  that  niay  be  present  will  bo  absorbed  in  two  or  tliree  minutes,  and 
the  gas  being  passed  back  again  into  ii  for  renieasurenient,  taking  care  to  shut  /  belbre  the 
caustic  potash  solution  reaciics  I ',  the  observed  diminution  in  volume  gives  tlie  amount  of 
carbonic  acid  present. 

The  amount  of  oyxgen  is  determined  in  like  manner  by  passing  up  into  i  a  few  drops 
of  a  saturated  solution  of  pyrogallic  acid,  which  forms  with  the  potash  already  present  pyro- 
gallate  of  potash.  The  gas  being  then  brought  back  into  i,  oxygen,  if  present,  will  be 
absorbed  in  a  few  minutes.  Its  amount  is  of  course  ascertained  by  j«neasuring  the  gas 
in  F. 

Tiie  next  stop  in  the  operation  consists  in  estimating  the  amount  of  olefiant  gas  and 
illuminating  hydrocarbons.  For  this  purpose,  whilst  the  gas,  thus  deprived  of  oxygen  and 
carbonic  acid,  is  contained  in  f,  the  tube  i  must  be  removed,  thoroughly  cleansed  and  dried, 
and  being  filled  with  mercur}-,  must  be  again  attached  to  /.  The  gas  must  now  be  trans- 
ferred from  F  to  I,  and  a  coke  bullet,  prepared  as  above  described,  being  passed  up  into  i, 
must  be  allowed  to  remain  in  the  gas  for  one  hour.  After  its  removal,  a  few  drops  of  a 
strong  solution  of  bichromate  of  potash  must  be  admitted  into  i  in  order  to  absorb  the  sul- 
phurous acid  and  vapors  of  anhydrous  sulphuric  acid  resulting  from  the  previous  operation. 
The  gas  is  now  ready  for  measurement ;  it  is  therefore  passed  into  f,  and  its  volume  deter- 
mined ;  the  diminution  which  has  occurred  since  the  last  reading  represents  the  volume  of 
olefiant  gas  and  illuminating  hydrocarbons  that  were  present  in  the  gas. 

It  now  only  remains  to  determine  the  respective  amounts  of  light  carburetted  hydrogen, 
carbonic  oxide,  hydrogen,  and  nitrogen  present  in  the  residual  gas.  This  is  effected  as  fol- 
lows : — As  much  of  the  residual  gas  as  will  occupy  about  l.V  inches  of  its  length  at  atmos- 
pheric pressure  is  retained  in  f,  and  its  volume  accurately  determined  ;  the  remainder  is 
passed  into  J,  and  the  latter  tube  removed,  cleansed,  filled  with  mercury,  and  reattached. 
A  quantity  of  oxygen  equal  to  about  three-and-a-half  times  that  of  the  combustible  gas  is 
now  added  to  the  latter,  and  the  volume  again  determined  ;  then  the  mixture  having  been 
expanded  to  about  the  sixth  division,  an  electric  spark  is  passed  through  it  by  means  of  the 
wires  at  m.  The  contraction  resulting  from  the  explosion  having  been  noted,  two  or  three 
drops  of  caustic  potash  solution  are  passed  into  J,  and  the  gas  is  then  transferred  into  the 
same  tube.  In  two  minutes  the  carbonic  acid  generated  by  the  explosion  is  perfectly  ab- 
sorbed, and  its  volume  is  determined  by  a  fresh  measurement  of  the  residual  gas.  The  lat- 
ter must  now  be  exploded  with  three  times  its  volume  of  hydrogen,  and  the  contraction  on 
explosion  noted.  These  operations  furnish  all  the  data  necessary  for  ascertaining  the  rela- 
tive amounts  of  light  carburetted  hydrogen,  carbonic  oxide,  hydrogen,  and  nitrogen,  accord- 
ing to  the  mode  of  calculation  given  above. 

Finally,  the  value  of  the  luminifero-us  constituents  is  obtained  as  before,  by  exploding 
about  a  cubic  inch  of  the  original  specimen  of  gas  with  from  four  to  five  times  its  volume 
of  oxygen,  and  noting  the  amount  of  carbonic  acid  produced. 

I.    Apparatus  used  in  the  Generation  of  Coal-Gas. 

Retorts. — The  use  of  this  portion  of  the  apparatus  is  to  expose  the  coal  to  a  high  tem- 
perature, to  exclude  atmospheric  air,  and  to  deliver  the  gaseous  and  vaporous  products  of 
distillation  into  the  refrigeratory  portion  of  the  apparatus.  The  materials  composing  t!ie 
retorts  should  therefore  possess  the  following  properties: — 1st,  high  conducting  power  for 
heat ;  2d,  rigidity  and  indestructibility  at  a  high  temperature  ;  and  3d,  impermeability  to 
gaseous  matter.  The  materials  hitherto  used  in  the  construction  of  retorts  are  cast-iron, 
wrought-iron,  and  earthenware ;  but  none  of  these  materials  possess  the  above  qualilica 
tions  in  the  high  degree  that  could  be  wished.  Thus  cast-iron,  though  a  good  conductor  of 
heat,  is  not  perfectly  rigid  and  indestructible.  At  high  temperatures  it  becomes  .'^liglifly 
viscous,  and  at  the  same  time  undergoes  rapid  oxidation.  AVrought-iron  is  a  still  bitter 
conductor  of  heat,  but  its  qualities  of  indestructibility  and  rigidity  are  even  lower  than 
those  of  cast-iron  ;  whilst  earthenware,  though  rigid  and  indestructible  by  oxidation,  is  a 
very  bad  conductor  of  heat,  and  is  moreover  very  liable  to  crack  from  changes  of  tempera- 
ture. Very  various  forms  of  retort  have  been  employed  at  different  times  in  order  to  secure, 
as  far  as  possible,  the  conditions  just  enumerated. 

Cant-Iron  Retorts. — The  chief  forma  of  the  cast-iron  retorts  are :  First,  the  cylindrical, 
fig.  174,  u.sed  in  the  Manchester  Gas  Works,  12  inches  diameter,  and  <'>  to  '.•  feet  hmg ; 
Second,  the  elliptical,  18  inches  by  12  inches,  by  (J  to  9  feet,///.   175;  Third,  the  car 


I7r. 


177 


(X) 


378 


COAL-GAS. 


shape,  fg.  176,  no-w  little  used,  2  feet  by  9  inches,  and  of  the  same  length  as  before ; 
P'ouith,' the  D-shaped  retort,  fg.  177,  20  inches  wide  and  14  inches  high.  This  form  of 
retort  is  at  present  far  more  extensively  used  than  any  of  the  others. 

Fig.  178  shows  a  bed  of  5  D-shaped  iron 
retorts.  The  length  is  7^  feet,  and  the  trans- 
verse area,  from  one  foot  to  a  foot  and  a  half 
square.  The  arrows  show  the  direction  of 
the  flame  and  draught. 

179 


The  charge  of  coals  is  most  conveniently  introduced  in  a  tray  of  sheet-iron,  made  some- 
what like  a  grocer's  scoop,  adapted  to  the  size  of  the  retort,  which  is  pushed  home  to  its 
further  end,  inverted  so  as  to  turn  out  the  contents,  and  then  immediately  withdrawn. 

All  these  retorts  are  set  horizontally  in  the  furnace,  and  they  have  a  flanch  cast  upon 
their  open  end,  to  which  a  mouthj)iece  a  a,  fig.  179,  can  be  securely  bolted.  The  mouth- 
piece is  provided  with  a  socket  b,  for  the  reception  of  the  staiidpipe,  and  also  with  an 
arrangement  by  which  a  lid  c  c  can  be  screwed  gas-tight  upon  the  front  of  the  mouthpiece, 
as  soon  as  the  charge  of  coal  has  been  introduced.  By  applying  a  luting  of  lime  mortar  to 
that  part  of  the  lid  which  comes  into  contact  with  the  mouthpiece,  a  perfectly  tight  joint  is 
detained. 

Sometimes  iron  retorts  are  made  of  double  the  above  length,  passing  completely  through 
the  furnace,  and  being  furnished  with  a  lid  and  standpipe  at  each  end.  Such  is  the  con- 
struction of  Mr.  Croll's  and  of  Lowe's  reciprocating  retorts.  These  retorts  are  charged 
from  each  end  alternately,  and  there  is  an  arrangement  of  valves  by  means  of  which  the 
gas  evolved  from  the  coal  recently  introduced  is  made  to  pass  over  the  incandescent  coke 
of  the  previous  charge,  at  the  opposite  end  of  the  retort.  It  is  highly  probable  that  some 
advantage  is  derived  from  this  arrangement  during  the  very  early  stage  of  the  distillation 
of  the  fresh  coal ;  but  on  the  whole,  for  reasons  stated  above,  the  principle  is  undoubtedly 
bad,  for  although  it  enables  the  manufocturer  to  produce  a  larger  volume  of  gas,  the  quality 
is  so  much  inferior  as  to  reduce  the  total  illuminating  effect  obtainable  from  a  given  weight 
of  coal. 

Wrought-Iron  Retorts. — ^fr.  King,  the  eminent  engineer  of  the  Liverpool  Gas  Works, 
has  for  many  years  successfully  used  retorts  of  wrought-iron.  They  are  made  of  thick  boiler 
plates,  riveted  together,  and  are  of  the  D  shape,  5^  feet  wide,  6  feet  long,  and  18  inches 
higli  at  the  crown  of  the  arcli.  About  1  ton  of  coal  can  be  worked  off  in  these  retorts  in 
2i  hours.  Occasionally  the  bottoms  are  of  cast-iron,  which  materially  prevents  the  great 
amount  of  warping  to  which  wrought-iron  is  subject  when  exposed  to  high  temperatures. 

Earthevware,  or  Clay  Jieforts. — These  are  usually  of  the  D  shape,  although  they  are 
occasionally  made  circular  or  elliptical.  Their  dimensions  are  about  the  same  us  those  of 
the  cast-iron  retorts  commonly  used,  but  their  walls  arc  necessarily  thicker,  varying  from  2^ 
to  4  inches  in  thickness ;  this,  added  to  the  circumstance  that  clay  is  a  very  bad  conductor 
of  heat,  undoubtedly  causes  the  expenditure  of  a  larger  amount  of  fuel  in  heating  these 
retorts  ;  nevertheless,  this  disadvantage  is,  perhaps,  less  than  might  be  supposed,  since  iron 
retorts  soon  become  coated  outside  with  a  thick  layer  of  oxide  of  iron,  which  also  greatly 
hinders  the  free  communication  of  heat  to  the  iron  beneath.  Moreover,  the  lower  price 
and  much  greater  duraljility  of  clay  retorts,  are  causing  their  almost  universal  adoption  in 
gas  works,  especially  since  the  removal  of  pressure  by  exhausters  greatly  reduces  the 
amount  of  leakage  to  which  clay  retorts  are  liable. 

The  following  is  an  extract  relating  to  clay  retorts,  from  the  "Reports  of  Juries"  of 
the  great  Exhibition  of  1851  : — 

"  The  use  of  lire-clay  is  not  of  very  ancient  date,  and  has  greatly  increased  within 
the  last  few  years.     It  is  found  in  England  almost  exclusively  in  the  coal  measures,  and 


COAL-GAS. 


37? 


from  dififerent  districts  the  quality  is  found  to  differ  considerably.  The  so-called  "  Stour- 
bridge clay  "  is  the  best  known,  and  will  be  alluded  to  presently ;  but  other  kinds  are 
almost,  if  not  quite,  as  well  adapted  fur  the  higher  purposes  of  manufacture,  being  e(iually 
free  from  alkaline  earths  and  iron,  the  presence  of  which  renders  the  clay  fusible  when  the 
heat  is  intense.  The  proportions  of  silica  and  alumina  in  these  clays  vary  considerably,  the 
former  amounting  sometimes  to  little  more  than  50  per  cent.,  while  in  others  it  reaches  be- 
yond 70,  the  miscellaneous  ingredients  ranging  from  less  than  -i-  to  upwards  of  1  per  cent. 

"  The  works  of  Messrs.  Cowen  &  Co.  are  among  the  most  e.\lensive  in  England,  and 
they  obtain  their  raw  material  from  no  less  than  nine  different  seams,  admitting  of  great 
and  useful  mixture  of  clay  for  various  purposes. 

"  After  being  removed  from  the  mine,  the  clay  is  tempered  by  exposure  to  the  weather,  in 
some  cases  for  years,  and  is  then  prepared  with  extreme  care.  The  objects  chiefly  made  are 
fire-bricks  and  gas  retorts — the  latter  being  now  much  used,  and  preferred  to  iron  for  dura- 
bility. 

"  These  retorts  were  first  made  by  the  present  exhibitors  in  ten  pieces,  (this  being 
twenty  years  ago,)  and  since  then  the  number  of  pieces  has  been  reduced  successively  to 
four,  three,  and  two  pieces,  till  in  1S4-1  they  were  enabled  to  patent  a  process  for  making 
them  in  one  piece,  and  at  the  present  time  they  are  thus  manufactured  of  dimensions  as 
much  as  10  feet  long  by  3  feet  wide  in  the  inside,  which  is,  however,  more  than  double  the 
size  of  the  largest  exhibited  by  them. 

180 


\\%;v\\XV^^i\v' -  ;\-}&;s\- ■  \V%«>^<^\\X?^«i3?^ 


380 


COAL-GAS. 


"  Gas  retorts  of  very  fair  quality  are  shown  by  Mr.  Ramsay  of  Newcastle,  who  has  also 
succeeded  extremely  well  in  the  manufacture  of  fire-bricks.  The  retorts  show  a  little  more 
iron  than  is  desirable,  but  the  exhibitor  has  been  considered  worthy  of  honorable  mention. 
Ketorts  of  less  creditable  appearance  are  exhibited  by  Messrs.  Hickman  &  Co.  of  Stour- 
brido-e,  and  Mr.  A.  Potter  of  Newcastle.  The  surface  of  both  these  retorts  is  cracked  and 
undulating.  When  we  consider  the  high  and  long-continued  temperature  to  which  these 
objects  are  exposed,  the  absolute  necessity  of  attending  to  every  detail  in  mixing  the  clay 
and  moulding  the  retort  will  be  at  once  recognized,  and  the  apparently  slight  defects  of 
some  of  those  sent  for  exhibition  reciuire  to  be  noticed  as  of  real  importance. 

"  Next  to  England,  the  finest  specimens  of  fire-clay  goods  on  a  large  scale  are  from  Bel- 
gium :  the  gas  retort  sent  from  France  is  not  remarkable  for  excellence." 

Fig.  ISO  is  an  elevation  of  Mr.  "Wright's  plan  for  a  range  of  long  clay  retorts. 

Fij.  181  shows  the  plans  and  sections  of  the  setting  for  these  retorts. 

181 


COAX-GAS. 


381 


Retorts,  or  rather  ovens,  of  fire-brick,  the  invention  of  Mr.  Spinney,  have  been  long 
used  successfully  at  Exeter,  Cheltenham,  and  other  places.  They  appear  to  be  very  durable, 
and  to  require  little  outlay  for  repairs,  but  a  very  large  expenditure  of  fuel  is  required  for 
heating  them.  They  are  of  the  D  shape,  7  feet  long,  3  feet  2  inches  wide,  and  14  inches 
higii  at  the  crown  of  the  arch.  Each  retort  receives  a  charge  of  5  or  6  cwt.  of  Newcastle 
or  Wesh  coal  every  12  hours,  and  produces  gas  at  the  rate  of  9,000  cubic  feet  per  ton  of 
Welsh,  and  10,000  to  12,000  per  ton  of  Newcastle  coal. 

Clegg's  Ret'oluing  Web  Retort. — This  retort,  the  invention  of  Mr.  Clegg,  sen.,  makes 
the  nearest  approach  to  a  truly  philosophical  apparatus  for  the  generation  of  gas  ;  in  it  the 
coal  is  exposed  to  a  sudden  and  uniform  heat,  in  a  thin  stratum,  by  which  means  the  gases 
are  liberated  at  once,  and  under  the  conditions  most  favorable  for  the  production  of  a  maxi- 
mum amount  of  illuminating  constituents.     Very  little  tar  is  produced  from  this  retort. 

Fig.  182  represents  a  section  of  this  retort,  which  is  of  the  D  shape,  with  a  very  low 
and  flat  arch.  It  is  made  of  wrought-iron  boiler  plates  riveted  together,  e  is  a  hopper 
for  holding  the  coal  to  be  carbonized  ;  f  is  a  discharging  disc  ;  g  is  the  retort ;  h  is  a  wob 
on  to  which  the  coal  is  discharged  by  the  disc  f  ;  1 1  are  revolving  drums  carrying  the 
wrought-iron  web  h  ;  l  l  are  the  tiues  from  a  lateral  furnace  by  which  the  retort  is  heated  ; 
M  is  the  exit  pipe  for  the  coke,  its  lower  extremity  is  either  closed  by  an  air-tight  door,  or 
is  made  to  dip  into  water. 


182 


All  the  coal  must  be  reduced  to  fragments  about  the  size  of  coffee  berries,  and  a  24 
hours'  charge  must  be  placed  at  once  in  the  hopper,  and  secured  by  a  luted  cover.  The  dis- 
charging disc  has  6  spurs,  and  is  made  to  revolve  uniformly  with  the  drum  below  it  at  the 
rate  of  4  revolutions  per  hour.  The  diameter  of  the  hexagonal  drums  is  so  regulated,  tliat 
the  coal,  which  fills  upon  the  wel>  from  the  discharging  disc,  will  at  one  revolution  have 
passed  the  entire  length  of  the  retort.  The  passage  through  the  retort  occupies  15  min- 
utes, which  is  quite  sufficient  to  expel  the  whole  of  the  gas  from  the  coal.  In  each  revolu- 
tion of  the  disc  and  drum,  745  cubic  inches  of  coal  (or  21  lbs.)  are  distributed  over  a  hcatid 
surface  of  2,016  square  inches.  18  cwt.  of  coal  is  carbonized  in  one  of  these  retorts  in  24 
hours,  and  the  production  of  gas  is  equal  to  1 2,000  cubic  feet  per  ton  of  Newcastle  coal. 
The  quality  of  the  gas  is  also  considerably  superior  to  that  obtained  from  the  same  coal  in 
the  ordinary  retorts. 

Although  the  first  cost  of  these  retorts  and  accompanying  machinery  is  considei-ahly 
greater  tlian  that  of  the  retorts  in  ordinary  use,  yet  the  dcstructil)le  parts  can  be  replaced 
-at  about  the  same  cost  as  that  required  to  replace  the  latter.  The  coke  produced  is  greater 
in  quantity,  but  inferior  in  quality,  owing  to  its  more  minute  state  of  division.  The  minor 
advantages  attendant  upon  this  form  are,  that  it  occupies  less  space,  requires  much  less  man- 
ual labor,  and  enables  the  retort-house  to  be  kept  perfectly  clean,  wholesome,  and  free  from 
suffocating  vapor.  If  the  principle  of  this  plan  could  be  combined  with  less  complication 
of  details,  it  would  no  doubt  come  into  extensive  use.      ' 


382 


COAL-GAS. 


II.    Thk  Rf.frigkratort  Apparatus. 

From  the  moment  that  the  gas  leaves  the  retorts,  it  is  subjected  to  cooling  influences 
which  gradually  reduce  its  temperature,  until  on  leaving  the  so-called  condenser  its  temper- 
ature ought  to  be  only  a  few  degrees  higher  than  that  of  the  atmosphere,  except  iu  winter, 
whea  it  is  advisable  to  maintain  a  heat,  relatively  to  the  external  air,  greater  than  in  sum- 
mer. The  gas  leaves  the  retort  by  the  sta7idpipcs  a  a  a,  fiff.  183,  which  are  of  cast-iron, 
5  inches  in  diameter  at  their  lower  extremity,  and  :?lightly  tapering  upwards.     Some  of  the 

least  volatile  products  of  decomposition 


183 


nnann 


/!S 


A 


I 


condense  in  these  pipes,  but  their  prox- 
imity to  the  furnaces,  and  the  constant 
rush  of  heated  gas  and  vapor  through 
them,  prevent  more  than  a  very  slight 
amount  of  refrigeration.  They  conduct 
to  the  hijdraulic  main,  which  is  shown 
at  B, /?^.  183.  It  cousists  of  a  cyhnder 
running  the  entire  length  of  the  retort 
house,  and  fixed  at  a  sufficient  height 
above  the  mouths  of  the  retorts  to  pro- 
tect it  from  the  flame  issuing  from  the 
^_  latter  during  the  times  of  charging  and 

L^^^fe^^^  drawing.     The  diameter  varies  from  12 

i^--^^--^rLJsc_---%LJ,  to  18  inches,  and  the  recurved  extremi- 

ties of  the  standpipcs  {the  dip-pipes)  c  c 
c  c,  pass  through  it  by  gas-tight  joints, 
and  dip,  to  the  extent  of  3  or  4  inches, 
into  the  condensed  liquids  contained  in 
the  hydraulic  main.  The  use  of  this 
portion  of  the  apparatus  is  to  cut  off 
the  communication  in  the  reverse  direc- 
tion between  the  gas  beyond  the  stand- 
pipes  and  the  retorts,  so  as  to  prevent 
the  former  rushing  back  down  the 
standpipe  during  the  time  that  the  lid  of  the  retort  is  removed.  Being  maintained 
half  full  of  tar  it  effectually  seals  the  lower  ends  of  the  dip-pipes,  and  prevents  any 


n 


rf 


aEIS^fidts 


UaJ 


pJ^-lVJ-^-T-JN-^-^ 


COAL-GAS. 


383 


return  of  gas  towards  the  retorts.  The  condensed  products,  consisting  chiefly  of  tar, 
make  their  exit  from  the  hydraulic  main  by  the  pipe  d,  which  leads  them  to  the  tar  well. 
From  the  hydraulic  main  the  gas  passes  to  the  condense);  the  office  of  which,  as  its  riaine 
implies,  is  to  effect  the  condensation  of  all  those  vapors  which  could  not  be  retained  by  the 
gas  at  the  ordinary  atmospheric  temperature.  The  condenser  has  received  a  variety  of 
lorms,  but  the  one  which  appears  to  unite  in  the  highest  degree  simplicity  and  efficiency,  is 
the  invention  of  Mr.  Wright,  of  the  Western  and  Great  Central  Gas  Companies.  Its  con- 
struction is  shown  in  Jiff.  184.  a  A  a  a  are  5  double  concentric  cast-iron  cylinders,  throu^di 
wliich  the  gas  is  made  to  circulate  in  succession  by  means  of  the  ticpipes  b  b  b  b,  whilst  the 
inner  cylinders  being  open  above  and  below,  a  current  of  air,  set  in  motion  by  tlieir  heated 
'walls,  rushes  through  them,  thus  securing  both  an  internal  and  external  refrigeratory  action. 
It  will  be  also  seen  by  a  reference  to  the  figure,  that  the  heated  gas  enters  these  cylinders 
at  the  top,  taking  an  opposite  direction  to  that  pursued  by  the  external  and  internal  currents 
of  air,  and  thus  securing  the  most  perfect  refrigeration,  by  bringing  the  gas  constantly  in 
proximity  to  air  of  increasing  coldness.  Each  cylinder  is  furnished  at  bottom  with  a  tar 
receptacle  c,  for  the  collection  of  the  condensed  products,  which  are  carried  to  the  tar  well 
by  a  pipe  not  shown  in  the  figure.  The  details  of  construction  are  sufficiently  seen  I'rom 
the  drawing,  and  require  no  further  descriptiom 

In  some  country  works  the  condenser  is  used. 

The  extent  of  surface  which  the  gas  requires  for  its  refrigeration  before  it  is  admitted 
into  the  washing-lime  apparatus,  depends  upon  the  temperature  of  the  milk  of  lime,  and 
the  C[uantity  of  gas  generated  iu  a  certain  time. 

It  may  be  assumed  as  a  determination  sufficiently  exact,  that  10  square  feet  of  surface 
of  the  condenser  can  cool  a  cubic  foot  of  gas  per  minute  to  the  temperature  of  the  cooling 
water.  For  example,  suppose  a  furnace  or  arch  with  5  retorts  of  150  pounds  of  coal  each, 
to  produce  in  5  hours  3,000  cubic  feet  of  gas,  or  10  cubic  feet  per  minute,  there  would  be 
required,  for  the  cooling  surface  of  the  condenser,  100  square  feet  =:  10  x  10.  Suppose 
100,000  cubic  feet  of  gas  to  be  produced  in  24  hours,  for  which  8  or  9  such  arches  must  be 
employed,  the  condensing  surface  must  contain  from  800  to  900  square  feet. 

After  the  action  of  the  condenser,  the  gas  still  retains,  chiefly  in  mechanical  suspension, 
a  certain  quantity  of  tarry  matter,  besides  a  slight  percentage  of  ammonia.  To  free  it  from 
these,  it  is  passed  through  a  scrvbber  d,  (Jiff.  184,)  which  consists  of  a  tall  cylinder  filled 
with  bricks,  paving  stones,  or  coke,  and  having  an  arrangement  by  which  a  stream  of  water 
can  be  admitted  at  top  and  removed  at  bottom.  The  chief  use  of  the  water  is  to  remove 
ammonia  from  the  gas,  but  as  it  also  dissolves  some  of  the  luminifcFous  hydrocarbons,  its 
use  is  objected  to  by  Mi-.  Wright,  and  dry  scrubbers  are  now  used  at  the  Western  Gas 
Works.  It  is  also  considered  'by  the  same  gentleman,  that  the 'detention  of  a  certain  per- 
centage of  ammonia  by  the  gas,  is  rather  an  advantage  than  otherwise,  as  it  serves  in  part 
to  neutralize  the  sulphurous  acid  which  is  inevitably  produced  by  the  combustion  even  of 
the  best  gas.  It  must,  however,  be  borne  in  mind,  that  the  presence  of  ammonia  in  gas 
gives  rise  to  the  formation  of  nitric  acid  during  its  combustion. 

77ie  Exhauster. — The  passage  of  the  gas  through  the  liquid  of  the  hydraulic  main,  and 
the  other  portions  of  apparatus  between  the  retorts  and  gas-holder,  causes  a  very  consider- 
able amount  of  pressure  to  be  thrown  back  upon  the  retorts, — an  effect  which  is  productive 
of  mischief  in  two  ways ;  in  the  first  place,  if  there  be  any  fissure  or  flaw  in  the  retorts,  or 
leakage  in  the  joints,  the  escape  and  consequent  loss  of  gas  is  greatly  augmented  ;  and  in 
the  second  place,  it  has  been  ascertained  by  Mr.  Grafton,  of  Cambridge,  that  pressure  in  the 
retorts  causes  the  decomposition  of  the  illuminating  hydrocarbons  with  greatly  increa.'^ed 
rapidity.  It  is,  therefore,  very  desirable  to  remove  nearly  the  whole  of  this  pressure  by 
mechanical  means,  and  this  is  now  done  in  all  well-arranged  works,  by  the  use  of  an  appa- 
ratus termed  an  exhauster.  Several  forms  of  exhausters  are  in  use,  but  it  will  be  necessary 
only  to  describe  that  of  "Mr.  J.  T.  Beale,  which  has  been  found  by  experience  to  be  very 
effective  and  economical.  It  is  shown  in  section  in  Jiff.  185.  The  axle  a  is  reduced  at  eaeli 
end,  and  passes  into  two  cylindrical  boxes  bored  to  a  larger  diameter  than  the  axle  at  those 
parts;  and  in  the  annular  space  between  the  axle  and  the  box  antifriction  rollers  are  intro- 
duced, their  diameter  being  equal  to  tlie  width  of  the  annular  space  ;  the  box  at  one  end  is 
fitted  with  a  stuffing-box,  through  which  the  axle  passes  for  the  application  of  the  driving 
power.  T'pon  motion  being  given  to  the  axle,  the  sliding  pistons  bb  are  carried  with  it.' 
These  sliding  pistons  are  furnished  at  their  ends  with  cylindrical  pins  which  ]irojeet  and  lit 
into  cylindrical  holes  bored  in  the  guide  blocks  c  c,  which  fit  into  annular  recesses  i)  in  the 
end  plates,  and  keep  the  slides  in  contact  with  the  cylinder.  The  slides  are  fitted  with  me- 
'tailic  packing  e,  to  allow  of  wear.  The  axle  continuing  to  revolve,  as  one  slide  reaches  the 
outlet  and  ceases  to  exhaust,  the  other  comes  into  action,  and  the  exhaustion  is  unceasing. 
Thus  the  pressure  upon  the  retorts  (which  is  indicated  by  a  gauge)  is  reduced  to  about  half 
an  inch  of  water. 

In  order  to  judge  of  the  degree  of  purity  of  the  gas  after  its  transmission  through  the 
lime  machine,  a  slender  siphon  tube  provided  with  a  stopcock  may  have  the  one  end  in- 


384 


COAL-GAS. 


serted  in  its  cover,  and  the  other  dipped  into  a  vessel  containing  a  solution  of  acetate  of 
lead.     'Whenever  the  solution  has  been  rendered  turbid  by  the  precipitation  of  black  sul- 

185 


phuret  of  lead,  it  should  be  renewed.  The  saturated  and  fetid  milk  of  lime  is  evaporated 
in  oblong  cast-iron  troughs  placed  in  the  ash-pit  of  the  furnaces,  and  the  dried  lime  is  partly 
employed  for  luting  the  apparatus,  and  partly  disposed  of  for  a  mortar  or  manure. 

III.  Apparatus  used  in  the  Pcrification  of  Coal-Gas. 

Fiqs.  186  and  187  represent  the  form  of  a  dry  purifier,  combined  with  a  washer  or 
scrubber,  lately  patented  by  Mr.  Lees  of  Manchester.  Fig.  186  is  an  elevation,  partly  in 
section  of  this  apparatus,  and  fy.  187  is  another  elevation,  also  partly  in  section,  of  the 
same,  a  is  a  hopper,  into  which  the  dry  lime  is  fed ;  b  is  a  damper,  or  sliding  door,  by 
which  the  supply  of  lime  can  be  regulated  ;  c  is  a  .'iheet  metal  tube,  containing  the  worm  or 
screw  d,  the  axis  of  which  is  supported  at  one  end  by  the  stuffing-box  f,  and  at  the  other 
end  by  the  bearing  /.  A  slow  revolving  motion  is  given  to  the  worm  d  from  the  driving 
shaft  fj,  )jy  means  of  the  bevel  wheels  A,  upright  shalt  i,  worm  j,  and  worm  wheel  l\  fixed 
on  the  axis  of  the  worm. 

The  lime  in  the  hopper  a,  is  kept  in  motion  by  the  screw  n,  which  is  turned  slowly 
round  by  the  worm  g,  the  worm  wheel  o  and  bevel  wheels  //,  one  of  which  is  fixed  on  the 
screw  n.  The  tube  c'is  open  at  <■',  to  admit  the  dry  lime  from  the  hopper  a,  and  the  worm 
or  screw  d  is  furnished  with  cross  pieces  d'  to  agitate  the  lime,  which  is  gradually  moved 
from  the  hopper  to  the  other  end  of  the  tube  c,  by  the  revolving  of  the  worm.  Below  the 
tube  c  is  another  tube  l\  y  h  a  siphon,  by  which  the  washing  fluid  is  supplied  and  con- 
ducted to  the  chamber  s,  which  then  flows  down  the  tube  I  to  the  chamber  r,  keeping  the 
level  indicated  by  j  b.  z  are  two  paddles,  fixed  upon  the  circular  perforated  plates,  which 
are  set  to  an  angle,  and  secured  to  the  shaft »«',  and  are  revolved  speedily  by  the  strap  and 
pulleys  X.  These  agitators  serve  to  increase  the  action  of  the  washing  fluid  contained  in 
the  tiibe  I,  bv  which  the  gas  is  washed  previous  to  passing  through  the  dry  lime  purifier. 

The  mode  of  operation  is  as  follows : — ^The  gas  to  be  purified  is  admitted  through  the 
pipe  7,  to  the  chamber  >•,  from  whence  it  passes  along  the  tube  /,  as  shown  by  the  arrows, 
to  the  chamber  .? ;  it  then  rises  into  the  chamber  t  and  enters  the  tube  c,  along  which  it 
passes  in  the  direction  shown  by  the  arrows  whence  it  may  be  conveyed,  through  the  pipe 
«;,  to  the  gasometer. 


COAL-GAS. 


385 


186 


■  '■  r,  i  i   A   / :    A   AWAx"*    fi   n    n    •"■•    '"^    n    'i    f 


:;4{_EE±CE^r  - t'T'-TSfp^^^^}^  ^ 


^^u^^:::^:::;^; 


It  will  be  apparent,  as  the  gas  passes  along  the  tube  I,  containing  the  agitators  >«,  which 
are  caused  to  revolve  speedily  by  the  motion  given  by  the  straps  and  speed  pulleys  x,  that 
the  washing  fluid,  which  is  passing  regularly  through  the  siphon  y,  and  running  into  the 
chamber  s,  and  along  the  tube  I,  into  the  chamber  r, 
keeping  the  level  as  shown  by  j  b,  is  caused  to  be  re- 
volved into  a  centrifugal  motion  round  the  tube  I,  by 
the  two  paddles  z,  placed  upon  the  circular  perforated 
plates,  secured  upon  the  shaft  ??2,  which  arc  set  to  an 
angle,  thereby  causing  a  counter-motion  from  left  to 
right  of  the  tube  I,  and  causing  the  washing  fluid  to  be 
wrought  into  a  complete  spray  amongst  the  gas,  whereby 
the  heavier  parts  of  the  impurities  are  carried  away 
more  effectually  than  by  any  other  washers  in  use. 

The  gas  then  enters  the  chamber  t  through  the  tube 

c,  passes  along  the  coils  or  threads  of  the  worm  or  screw 

d,  and  as  the  cross  pieces  d'  are  set  to  an  angle,  as  shown 
in  fiff.  187,  the  lime  is  raised  from  the  lower  to  the  upper 
part  of  the  tube  c,  and  then  drops  down  to  the  gas  that 
is  making  its  way  towards  the  openings  c" ;  consequently, 
the  lime  and  the  gas  become  most  intimately  mixed, 
whereby  the  lime  is  made  to  absorb  a  much  greater  pro- 
portion of  the  impurities  contained  in  the  gas  than  is 
effected  by  the  dry  lime  purifiers  usually  employed,  in 
which  the  lime  is  supported  on  stationary  trays.  The 
lime  dropping  into  the  tube  c  from  the  hopper  a,  is 
worked  gradually  towards  the  chamber  ?',  into  which  it 
drops.  The  speed  of  the  screw  or  worm  d,  the  number 
of  threads  upon  it,  the  length  and  diameter  thereof, 
must  be  made  to  suit  the  quantity  of  gas  to  be  purified 
per  hour.  The  lime  which  drops  into  the  chamber  t, 
may  be  removed  therefrom  through  the  manhole  w.  Mr. 
Lees  states  that  a  considerable  saving  is  effected  in  the 
lime,  owing  to  each  particle  or  atom  being  kept  in  mo- 
tion, and  falling  repeatedly  through  the  gas  in  its  passage  . 
from  one  end  of  the  tube  to  the  other,  and  that  there  is  also  a  great  saving  in  labor. 

Another  form  of  wet  purifier,  which  might  also  be  advantageously  used  as  a  scrubber, 
or  as  u  naphthalizer,  has  recently  been  invented  by  M.  Colladou  of  Geneva,  and  is  now  iu 
Vol.  III.— 25 


686 


COAL-GAS. 


188 


■      ^^~"         '■■'  _~)ii  I    ^  .:■...-■   r  .     •'~ 


use  in  the  gas  manufactory  of  that  city.  This  apparatus,  as  shown  in  vertical  section  in 
_/?//.  188,  consists  of  a  section  of  a  very  obtuse  cone  a',  the  angle  of  incHnation  of  which  is 
164°.  Its  upper  and  smaller  end  is  joined  to  a  metal  cylinder  a,  placed  on  the  same  axis 
as  a',  and  about  its  own  diameter  in  height.  At  top  it  is  closed  by  a  cast-iron  plate  k, 
through  which  the  axle  c  passes  :  the  latter  communicates  a  rotary  motion  to  the  cylinder 
and  cone  a  and  a'.  It  is  inclined  8°  from  the  perpendicular,  and  rests  upon  the  steel  point 
of  the  centre  pin  b',  whilst  at  top  it  carries  a  pulley  by  which  a  circular  motion  is  communi- 
cated to  it.  a  a  are  a  series  of  metal  discs  which  stand  vertically  to  the  inner  surface  of 
the  cone  a',  with  spaces  of  about  one  inch  between  them.  The  discs  are  arranged  concen- 
trically, and  have  spaces  corresponding  to  the  quantity  of  gas  which  has  to  pass  through 
them.  They  are  from  5  to  7  inches  long.  As  the  axle  c  and  cylinder  a  are  not  vertical, 
but  somewhat  inclined,  one  side  of  the  cone  a'  will,  during  the  revolution,  be  in  a  nearly 
horizontal  position,  whilst  the  opposite  side  will  be  immersed  in  the  liquid  to  the  extent  of 
about  16'.  The  whole  of  this  mechanism  is  enclosed  in  a  sheet-iron  lid  B.  The  centre  pin 
b  is  attached  by  a  cross-bar  to  the  lower  edge  of  b,  whilst  the  axle  c  is  supported  by  d, 
whch  is  also  attached  to  b.  d'  d'  is  a  water  joint  permitting  of  the  free  motion  of  c.  The 
lid  B  thus  contains  the  whole  of  the  washing  apparatus,  and  it  is  held  in  its  proper  position 
in  the  trough  c  by  lateral  attachments,  d  is  the  inlet  pipe  opening  into  the  cylinder  a, 
from  which  it  has  to  make  its  way  through  the  discs  a  a  to  the  outlet  e.  This  apparatus 
gives  no  sensible  pressure,  and  requires  a  very  small  motive  power. 


189 


190 


Fig.  189  represents  an  arrangement 
of  four  of  the  dry  purifiers,  worked  by  a 
central  valve,  as  used  at  the  present  time 
in  most  large  gas-works  ;  it  is  the  inven- 
tion of  Mr.  Malam,  and  is  described  in  Mr. 
Peckston's  treatise,  a,  b,  c,  d,  are  the 
four  purifiers  connected  with  the  central 
valve  E  in  such  a  way  as  to  permit  of 
three  of  them  being  at  work  whilst  the 


COAL-GAS. 


387 


fourth  is  emptied  and  recharged.  The  outer  case  of  the  central  valve  e,  is  a  cylinder  of 
cast-  or  wrought-iroD,  5  to  6  feet  in  diameter  and  3  to  4  feet  deep.  Its  floor  receives  the 
open  ends  of  10  pipes  conducting  the  gas  from  the  condenser  or  exhauster  to  the  different 
purifiers,  and  then  to  the  gas-holders  ;  the  ends  of  these  pipes  project  upwards  to  the  height 
of  14  inches,  and  the  vessel  e  is  filled  with  water  to  the  height  of  12  inches,  thus  leaving 
the  orifice  of  the  pipes  2  inches  above  the  water  level.  This  cylinder  has  a  cover  which 
consists  of  a  smaller  cylinder,  open  below  and  closed  above,  fitting  into  e,  so  as  to  form  a 
water  lute.  Its  interior  is  divided  into  5  chambers,  as  shown  in  fig.  190,  and  when  the 
cover  is  so  far  lowered  into  e  as  to  immerse  the  edges  of  these  chambers  into  the  water, 
they  each  connect  together  a  pair  of  pipes,  as  shown  in  fig.  189,  at  e,  which  exhibits  a  hori- 
zontal section  through  these  chambers.  The  chambered  cover  being  placed  in  the  position 
shown  in  fig.  189,  the  gas  takes  the  following  course  :  it  enters  the  chamber  a!  by  the  pipe 
a  a,  passes  through  the  pipe  marked  1  into  the  bottom  of  the  purifier  c,  and  after  traversing 
the  layers  of  purifying  material  in  c,  it  returns  to  chamber  e  of  the  central  valve  by  the 
pipe  2 ;  thence  by  pipe  3,  it  enters  the  purifier  d,  and  returns  to  chamber  d  of  the  valve 
by  pipe  No.  4.  From  this  chamber  it  can  only  make  its  exit  by  pipe  No.  5,  which  conducts 
it  into  B,  whence  it  returns  to  chamber  b  by  pipe  No.  6,  and  from  this  chamber  it  finally 
passes  to  the  gas-holder  through  the  exit  pipe  b  b.  Thus  the  purifier  a  is  left  out  of  the 
circuit  for  the  purpose  of  recharging  or  revivification  ;  but  when  the  material  in  c  has  be- 
come exhausted,  it  can  be  replaced  in  the  circuit  by  a,  by  slightly  raising  the  cover  of  e, 
and  turning  it  round  so  as  to  bring  the  chamber  a!  over  pipe  3,  and  again  depressing  it  to 
its  former  position ;  by  this  arrangement  d,  b  and  a  become  the  working  purifiers,  whilst  c 
will  be  thrown  out  of  the  circuit.  Thus,  by  the  action  of  the  central  valve  e,  each  of  the 
four  purifiers  can  in  turn  be  excluded  from  the  circuit,  and  recharged  or  revivified. 

191 


77«!  Governor. — Altliough  the  gas-holder  is,  to  a  certain  extent,  a  regulator  of  pressure, 
yet  it  is  difficult,  by  its  action  alone,  to  maintain  a  pressure  so  steady  and  uniform  as  that 
required  for  the  supply  of  gas  consumers.     It  would  be  difficult,  if  not  impossible,  to  alter 


388 


COAL-GAS. 


the  pressure  upon  the  mains  frequently  during  a  single  night,  as  is  now  usually  done  in 
towns  with  a  large  number  of  street  lamps,  without  the  intervention  of  an  apparatus  termed 
a  governor.  The  governor,  which  occupies  a  position  between  the  gas-holder  and  supply 
mains,  is  a  miniature  gas-holder  a,  (see  fgs.  191,  192,  and  193,  which  represent  Mr. 

192 


Wright's  improved  governor,)  the  interior  of  which,  however,  is  nearly  filled  by  the  eon- 
centric  inlet  and  outlet  pipes  b  and  c.  Immediately  over  the  mouth  of  the  inlet  pipe,  and 
depending  from  the  roof  of  the  inner  cylinder,  is  a  parabolic  piston  d,  which  hangs  within 

193 


the  contracted  mouth  of  the  inlet  pipe  c.     The  interior  cylinder  is  counterpoised  by  the 
lever  and  weights  e  e.     Now,  when  the  pressure  of  gas  in  this  small  holder  increases, — that 


COAL-GAS.  389 

is,  when  the  flow  of  gas  through  the  inlet  pipe  exceeds  that  escaping  from  the  outlet, — the 
inner  cylinder  rises ;  but  in  doing  so,  it  carries  with  it  the  parabolic  piston  d,  and  thus  con- 
tracts the  orifice  of  the  inlet,  and  consequently  diminishes  the  ingress  of  gas.  In  this  way, 
by  adjusting  the  weights  attached  to  the  lever  of  the  governor,  and  by  always  maintaining 
a  pressure  in  the  gas-holder  greater  than  is  required  in  the  mains,  the  gas  can  be  delivered 
from  the  governor  at  any  required  pressure.  In  hilly  towns,  such  as  Bristol,  Bath,  Edin- 
burgh, &c.,  it  is  necessary  to  employ  governors  at  different  stages  of  elevation,  in  order  to 
produce  a  tolerably  uniform  pressure  in  the  different  districts.  The  necessity  for  this  will 
be  obvious,  when  it  is  stated,  that  a  difference  of  level  of  30  feet  affects  the  pressure  of  the 
gas  in  the  mains  to  the  extent  of  Vio  of  an  inch  of  water. 

Economical  and  Sanitary  Relations  of  Gas. 

In  a  lecture  delivered  at  the  Royal  Institution  in  1853,  Dr.  Frankland  thus  estimates 
the  comparative  cost  of  an  amount  of  light  from  various  sources  equal  to  that  yielded 
by  20  sperm  candles,  each  burning  120  grains  per  hour  for  10  hours. 

s.  d. 
London  gases:  City,  Great  Central, 

Imperial,  and  Chartered      -     0  4^ 

Western  -         -         -         -     0  2| 

Manchester  gas  -        -        -    0  3 

The  following  table  exhibits  the  amount  of  carbonic  acid  and  heat  produced  per  hour 
from  the  above  sources  of  light,  the  heat  generated  by  tallow  being  assumed  to  be  100 
for  the  purposes  of  comparison. 

Carbonic  Acid.  „  „j. 

Cubic  feet.  H^^*- 

Tallow 10-1         -         -         -     100 


s.   J. » 

Wax       .        -        -        - 

-  n   2i 

Spermaceti     - 

-     6     8 

Tallow   .... 

-     2     8 

Sperm  oil  (Carcel's  lamp) 

-     1  10 

Wax  ) 

Spermaceti   f 

Sperm  oil  (CarceFs  lamp)    -        .        -    6-4        .        -        .63 

London  gases  :    City  ~| 

Great  Central  ! 

Imperial  j 

Chartered       J 

Western    ...    3-0        -  -      22 


8-3         -        -        -       82 


5-0         -         -         -      47 


Manchester  gas  ....    4-0        -        .        -      32 

Notwithstanding  the  great  economy  and  convenience  attending  the  use  of  gas,  and,  in  a 
sanitary  point  of  view,  the  high  position  which,  as  an  illuminating  agent,  coal-gas  of  proper 
composition  occupies,  its  use  in  dwelfing-houses  is  still  extensively  objected  to.  The  objec- 
tions are  partly  well  founded  and  partly  groundless.  As  is  evident  from  the  foregoing 
table,  even  the  worst  gases  produce,  for  a  given  amount  of  light,  less  carbonic  acid  and  heat 
than  either  lamps  or  candles.  But  then,  where  gas  is  used,  the  consumer  is  never  satisfied 
with  a  light  equal  in  brilliancy  only  to  that  of  lamps  or  candles,  and  consequently,  when 
three  or  four  times  the  amount  of  light  is  produced  from  a  gas  of  bad  composition,  the  heat 
and  atmospheric  deterioration  greatly  exceed  the  corresponding  effects  produced  by  the 
other  means  of  illumination.  There  is  nevertheless  a  real  objection  to  the  employment  of 
gas-light  in  apartments,  founded  upon  the  production  of  sulphurous  acid  during  its  combus- 
tion :  this  sulphurous  acid  is  derived  from  bisulphuret  of  carbon,  and  the  organic  sulphur 
compounds,  which  have  already  been  referred  to  as  incapable  of  removal  from  the  gas  by 
the  present  methods  of  purification. 

These  impurities,  which  are  encountered  in  almost  all  coal-gas  now  used,  are  the  princi- 
pal if  not  the  only  source  of  the  unpleasant  symptoms  experienced  by  many  sensitive  per- 
sons in  rooms  lighted  with  gas.  It  is  also  owing  to  the  sulphurous  acid  generated  during 
the  combustion  of  these  impurities  that  the  use  of  gas  is  found  to  injure  the  bindings  of 
books,  and  impair  or  destroy  the  delicate  colors  of  tapestry.  Therefore  the  production  of 
gas  free  from  these  noxious  sulphur  compounds  is  at  the  present  moment  a  problem  of  the 
highest  importance  to  the -gas  manufacturer,  and  one  which  demands  his  earnest  attention. 

The  high  sanitary  position  which  gas  takes,  with  regard  to  the  production  of  a  minimum 
amount  of  carbonic  acid  and  heat  for  a  given  amount  of  light,  ouglit  to  stimulate  tlie  manu- 
facturer to  perfect  the  process,  by  removing  all  sulphur  compounds,  and  attaining  the  most 
desirable  composition,  so  that  this  economical,  and,  if  pure,  agreeable  and  sanitary  light, 
may  contribute  to  our  domestic  comfort  to  a  much  greater  extent  than  it  has  hitherto  done. 

Hydrocarbon  Gas. 

This  title  has  been  given  to  illuminating  gas  manufactured  according  to  a  patent  granted 
some  years  ago  to  Mr.  White  of  Manchester.  The  process  of  manufacture  consists  essen- 
tially in  the  generation  of  non-illuminating  combustible  gases  by  the  action  of  steam  upon 


390 


COAL-GAS. 


cliarcoal,  coke,  or  other  deoxidizing  substances,  in  a  separate  retort,  and  the  introduction 
of  these  gases,  technically  called  water-gas,  into  the  retort  in  which  the  illuminating  gases 
aio  being  generated,  and  in  such  a  manner  that  these  latter  gases  shall  be  swept  out  of  the 
retort  as  rapidly  as  possible,  so  as  to  remove  them  from  the  destructive  influence  of  a  high 
temperature. 

The  retorts  used  for  the  hydrocarbon-gas  process  may  be  of  various  shapes  and  sizes. 
The  settings  are  similar  to  those  for  the  ordinary  retorts,  and  any  number  which  is  neces- 
sary may  be  placed  in  an  oven.  They  difler  only  from  the  ordinary  retorts  by  having  a 
horizontal  partition,  or  diaphragm,  cast  in  the  centre,  dividing  the  retort  into  two  cham- 
bers, and  extending  to  within  12  inches  of  the  back.  This  diaphragm  is  found  in  practice 
to  strengthen  the  sides  of  tlie  retorts,  and  thus  to  add  to  their  durability.  The  water-gas 
retorts  may  be  cast  from  the  same  pattern  as  the  caunel  retorts,  and  may  be  set  in  exactly 
the  same  manner.     Figs.  193a  and  194  represent  a  setting  of  two  retorts  in  one  oven,  and 

193a 


^ 


show  the  same  in  elevation,  transverse  section,  and  longitudinal  section.  The  retorts  here 
shown  have  an  internal  cubical  capacity  of  about  16  feet,  and  the  bed  of  two  is  capable  of 
producing  about  10,000  cubic  feet  per  diem  of  hydrocarbon  gas.  The  temperature  at  which 
the  retorts  are  worked  is  about  the  average.  The  water-gas  is  generated  in  the  retort  a  in 
the  following  manner : — The  upper  and  lower  chambers  are  well  filled  with  coke  or  char- 
coal, and  a  very  fine  stream,  or  rapid  drops,  of  water  flowing  from  the  tap  enters  the  upper 
chamber  through  the  siphon  pipe,  falling  into  a  small  steam-generating  tube,  which  is  placed 
inside  to  receive  it,  and  instantly  converts  it  into  steam.  The  steam,  in  passing  backwards 
along  the  upper  chamber,  and  forwards  along  the  lower  one,  becomes  to  a  great  extent  de- 
composed into  hydrogen,  carbonic  o.xidc,  and  carbonic  acid  gases.  The  water-gas  generated 
in  the  retort  a,  as  described  above,  enters  the  lower  chamber  of  the  retort  b,  through  the 
connecting  pipe  c  o,  ca.^t  on  the  mouthpiece.  In  the  chambers  of  tliis  retort  the  illuminat- 
ing gas  is  generated,  either  from  coal,  cannel,  resin,  or  other  suitable  material,  and  being 
rapidly  carried  forward  by  the  current  of  water-gas,  its  illuminating  principles  are  preserved 
from  the  destruction  caused  by  prolonged  contact  with  the  incandescent  .'surfaces  in  the 
retort,  whilst  at  the  same  time  its  volume  is  increased.     When  very  rich  cannels  or  other 


COAL-GAS. 


391 


materials  are  used,  two,  three,  or 
even  four  water-gas  retorts  are  made 
to  discharge  their  gas  into  the  can- 
nel  retort. 

The  hydrocarbon  process  has 
hitherto  been  applied  only  to  resin, 
coals,  and  cannels.  The  following 
is  a  brief  summary  of  the  results 
of  a  series  of  experiments  made  by 
Dr.  Franliland  on  the  manufacture 
of  hydrocarbon  resin  gas:  Each 
hundred  weight  of  resin  was  dis- 
solved by  heat  in  7|-  gallons  of  the 
resin  oil  of  a  former  working,  and 
the  liquid,  whilst  still  hot,  was  run 
into  one  of  the  retorts,  by  means 
of  a  siphon  tube,  in  a  stream  about 
the  thickness  of  a  crowquill,  whilst 
water-gas,  generated  in  the  second 
retort,  was  admitted  as  described 
above.  The  mixed  gases  were  then 
made  to  stream  through  the  usual 
form  of  condensing  apparatus,  and 
were  afterwards  compelled  to  pass 
successively  through  wet  and  dry 
lime  purifiers  before  they  reached 
tlie  gas-holder.  In  order  to  secure 
a  uniform  mixture  of  the  gas  pro- 
duced in  each  experiment,  it  was 
allowed  to  remain  at  rest  in  the  gas- 
holder for  at  least  twelve  hours  be- 
fore a  specimen  was  withdrawn  for 
analysis. 

In  the  following  tables  both  the 
practical  and  analytical  results  are 
given. 

I. 


Practical  Results. 


Average 
evolu- 
tion of 

Gas  per 
hour. 

Materials  Consumed. 

Products  Obtained. 

Eesin. 

Coal. 

Char- 
coal. 

Lime. 

"Water. 

Eesin 
Oil. 

Gas. 

Gas  per 
cwt.  of 
Eesin. 

1st  Experiment 

2d 

3d           " 

4th          " 

Cubic  ft. 

930 
1,000 

Cwt.  qr.    lb. 
2       1    171 
2      1    18 
2      0  17 
2      0     7 

Cwt.  qr. 
1      2 
1     2 
1     2 
1     2 

lb. 
10 
12 
12 
10 

lb. 
20 
20 
28 

28 

lb. 
73 
77 
85 
621 

Gals. 

10-7 
7-8 
4-5 
8-75 

Cb.  ft. 
3,340 
3,800 
4,157 
3,090 

1,388 
1,576 
1,932 
1,520 

Average  production  of  gas  per  ton  of  resin     -         -         -         32,080  cubic  feet. 
Average  production  of  resin  oil  per  ton  of  resin      -         -         70'3  gallons. 
Illuminating  power  of  average  gas  before  purification,  as  ascertained  by  shadow  test, 
'75  cubic  feet  per  hour  =:  light  of  one  short  six  spermaceti  candle. 

II.  Analytical  JResidts. 


Composition  of 

Gas  depobb  Pukification. 

Aotual  Amount  id  Cubic  Feet. 

Percentage  Amount. 

1st  Exp. 

2d  Exp. 

3d  Exp.  4th  Exp. 

1st  Exp. 

'2d  Exp. 

3d  Exp. 

41h  Exp. 

Avernge. 

Hydrocarbons   - 
Lisrht  carbd.  hydrogen 
Hydrogen 
Carbonic  oxide 
Carbonic  acid    - 

2.58-7 
587-5 
13153 
967-9 
210-G 

2C9-0 
1. 527-7 
1274-8 
819-2 
409-5 

805-7 
805-9 
197(V2 

194-9 

254-0 
961-0 
1297-8 
463-5 
1137 

7-75 
17-58 
,S9-38 
28-98 

6-31 

7-OS 
40-20 
33-54 

8-40 
10-7S 

7-41 
21-71 
47-90 
18-26 

4-72 

8-22 
81-09 
42-06 
15-04 

3-59 

7-62 
27-64 
40-72 
17-67 

6-85 

3840-0 

3800-2 

4126-0    8090-0 

100-00 

100-00 

100-00 

100-00 

100-00 

Amount  of  carbon  yapor  contained  in  1  volume  of  hydrocarbons  =  2*8  volumes. 


392 


COAL-GAS. 


Composition  of  Gas  after  Pueification. 

1st  Exp. 

2d  Exp. 

8d  Exp. 

4th  Esp. 

Average. 

Hydrocarbons         .... 
Light  carburetted  hydrogen  - 
Hydrogen       .         -         .         .         - 
Carbonic  oxide       .        .        -        - 

8-27 
18-76 
42-03 
30-93 

7-94 
45-06 
37-59 

9-41 

7-78 
22-79 
50-27 
19-16 

8-53 
32-25 
43-62 
15-60 

8-13 
29-71 
43-38 
18-78 

100-00 

100-00 

100-00 

100-00 

100-00 

Specific  gravity  of  average  gas  before  purification  =  -65886. 
"  "  "  after  "  =:  -59133. 


Value  of  Htdkocabbons  expressed  in  their  equiva- 
lent Volume  of  Olefiant  Gas. 

Value  of  Actual  Amount. 

Value  of  Percentage  Amount 
in  Purified  Gas. 

1st  Experiment         .        .        - 
2d  Experiment          ... 
3d  Experiment          ... 
4th  Experiment 

Cubic  Feet. 
362-2 
376-6 
428-0 

Cubic  Feet. 
11-58 
11-12 
10-89 
11-94 

This  process  is  especially  adapted  for  the  manufacture  of  gas  on  a  small  scale,  as  in 
private  houses  or  small  manufactories.  The  necessary  operations  involve  little  trouble 
and  unpleasant  effluvia. 

Dr.  Frankland  has  also  investigated  the  hydrocarbon  process  as  applied  to  coals  and 
cannels,  and  the  following  is  a  tabulated  summary  of  his  experimental  results. 

Summary  of  Experimental  Results. 


Naue  of  Coal. 

Cubic  feet  of  Gas 
per  ton. 

niuminating 
power  per  ton  in 

Sperm  Candles. 

Gain  per  ton  by 
White's  process. 

Gain  per  cent,  by 
White's  process. 

By  o!d 
procefia. 

By 

White's 
process. 

By  old 
process. 

By 

White's 
process. 

Quantity 
of  gas  in 
cubic  feet. 

llluminat- 
ing  power 
ir.  sperm 
candles. 

Quantity 
of  Gas. 

Illumi- 
nating 
power. 

"Wigan  Cannel,  Ince  Hall   - 
"Wigan  dn.,  Balcarre.s  - 
Boghead  Canuel 
Ditto.  2d  experiment  - 
Lesmahago  Cannel 
Methill  Cannel    - 
Newcastle  do.,  Eamsey 

10,900 
10.440 
13,240 

10,620 
9,560 
10,300 

16,120 
15,500 
38.160 
51,720 
29,180 
26,400 
15,020 

4,816 
4.156 
11,340 

7,620 
5.316 
5,026 

6,448 
5,920 
21,368 

20,688 
1.3,934 
11.088 
5,646 

5,220 
5,060 
24,920 
38,480 
18.560 
16,840 
4,720 

1,632 
1,704 
9,988 
9.308 
6.314 
5,772 
620 

47-9 
48-5 
198-2 
290-6 
1748 
176-2 
458 

83  9 
42-4 

67-8 
81-8 
82-8 
lOS-1 
12-3 

Table,  showing  the  quantity  of  Coal  or  Cannel  requisite  for  producing  light  equal  to  1,000 
Sperm  Candles,  each  burning  10  hours  at  the  rate  q/"  120  grs.  per  hour. 


Name  of  Coal. 

TVeigut  of  Coal. 

B7  old  process. 

By  White's  process. 

Wigan  Cannel  (Ince  Hall) 
Wigan  Cannel  (Balcarres) 
Boghead  Cannel        ..... 

Lesmahago  Cannel 

Methill  Cannel 

Newcastle  Cannel 

Newcastle  Coal  (Pelton)    .... 

lbs.  • 
465-1 
539-0 
197-5 
293-9 
421-4 
445-7 
745-7 

lbs. 
347-4 
378-4 
104-8 
160-7 
202-0 
396-7 

COAL-GAS. 


393 


Table  Shoviing  the  quantity  of  Gas  requisite  for  producing  light  equal  to  1000  Sperm 
Candles,  each  burning  10  hours  at  the  rate  of  120  grs.  per  hour. 


Name  op  Gas. 

Kate  of  CoDsumption 
per  hour. 

Quantity  of  Gas. 

Cubic  Feet. 

Cubic  Feet. 

Wigan  Cannel  (Ince  Hall) 

5 

2263 

Ditto         by  White's  process   - 

6 

2500 

Wigan  Cannel  (Balcarres) 

5 

2512 

Ditto         by  White's  process   - 

5 

2618 

Boghead  Cannel     

3 

1168 

Ditto        by  White's  process   - 

3 

1786 

Ditto         ditto,  2d  experiment 

5 

2500 

Lesmahago  Cannel          .... 

4 

1394 

Ditto         by  White's  process   - 

4 

2094 

Methill  Cannel 

6 

1798 

Ditto        by  White's  process  - 

6 

2381 

Newcastle  Cannel  (Ramsay)     -         -         - 

5 

2049 

Ditto        by  White's  process   - 

5 

2660 

Newcastle  Coal  (Pelton) 

5 

33^6 

Resin  Gas  by  White's  process 

j       calculated 

\    from  analysis     ' 

3012 

Manchester  Gas  (June,  1851) 

ditto      ditto 

3448 

m 

rCity  Company's  Gas  (July  15,  1851)   - 

5 

3846 

m 

Great  Central  Company's  Gas,  do. 

5 

3546 

a  " 

Chartered  Company's  Gas         do. 

(       calculated 

\     from  analysis      ' 

3320 

•a 

Imperial  Company's  Gas  -         do. 

ditto      ditto 

4099 

o 

Western  Company's  Gas  -        do. 

ditto      ditto 

1538 

Dr.  Frankland  thus  sums  up  the  advantages  which  he  conceives  to  result  from  the  appli- 
cation of  the  hydrocarbon  process  to  coals  and  cannels  : — 

1.  It  greatly  increases  the  produce  in  gas  from  a  given  weight  of  coal  or  cannel,  the 
increase  being  from  46  to  290  per  cent.,  according  to  the  nature  of  the  material  operated 
upon. 

2.  It  greatly  increases  the  total  illuminating  power  afforded  by  a  given  weight  of  coal, 
the  increase  amounting  to  from  12  to  108  per  cent.,  being  greatest- when  coals  affording 
highly  illuminating  gases  are  used. 

3.  It  diminishes  the  quantity  of  tar  formed,  by  converting  a  portion  of  it  into  gases  pos- 
sessing a  considerable  illuminating  power. 

4.  It  enables  us  profitably  to  reduce  the  illuminating  power  of  the  gases  produced  from 
such  materials  as  Boghead  and  Lesmahago  cannels,  &c.,  so  as  to  fit  them  for  burning  with- 
out smoke  and  loss  of  light. 

Mr.  Barlow  has  also  experimented  upon  this  process  of  gas-making,  and  finds  that  a  very 
considerable  gain  in  total  illuminating  power  results  from  its  use. 

Mr.  Ciegg's  investigation  of  this  process  showed,  that  whilst  Wigan  Cannel  produces  by 
the  ordinary  process  of  gas-making  about  10,000  cubic  feet  of  20  candle  gas  per  ton, 
1(),000  cubic  feet  of  20  candle  gas,  or  26,000  cubic  feet  of  12  candle  gas  can  be  made 
from  the  same  quantity  of  material  by  the  hydrocarbon  process.  Also  that,  by  the  applica- 
tion of  the  same  process  to  Lesmahago  Cannel,  36,0()0  cubic  feet  of  20  candle  gas,  or 
58,000  cubic  feet  of  12  candle  gas  per  ton,  can  be  obtained  ;  whilst  Boghead  Cannel  yields 
52,000  cubic  feet  of  20  candle  gas,  or  75,000  cubic  feet  of  12  candle  gas.  The  following 
table  presents  in  a  condensed  form  Mr.  Ciegg's  results  as  to  comparative  cost : — 


Name  of  Coal. 

Cost  of  1000  feet  of 

20  candle  gas  by  old 

process. 

Cost  of  1000  feet  of 
20  candle  pas  by  hy- 
drocarbon process. 

Cost  of  lOno  feet  of 
12  candle  pas  by  hy- 
drocarbon process. 

Wigan  Cannel  at  14s.  per 

s.      d. 

s.      d. 

s.       (/. 

ton       -         -         .         . 

Lesmahago  Cannel  at  IBs. 

1      Of 

1      3.J 

0  Hi 

per  ton         ... 
Boghead  Cannel  at  20s.  per 

2     5i 

0  llf 

0     9J 

ton      .        -        -        - 

2     4i 

0  11 

0     9J 

394  COAL-GAS. 

Wood  Gas. 

Attempts  were  first  made  in  France  towards  the  close  of  the  last  century  to  manufac- 
ture an  illuminating  gas  from  wood.  The  Tliermolanip  of  Lebon,  a  wood-gas  apparatus, 
then  and  for  some  time  afterwards  excited  considerable  attention,  especially  in  the  districts 
of  Germany,  Sweden,  and  Russia,  where  coals  are  scarce.  This  mode  of  illumination 
proved,  however,  to  be  a  complete  failure,  owing  to  the  very  feeble  illuminating  power  of 
the  gas  produced,  and  as  at  this  time  the  production  of  gas  from  coal  was  rapidly  becoming 
better  known,  any  thing  like  a  regular  manufacture  of  wood-gas  never  in  any  case  gained  a 
footin".  Subsequent  trials  only  confirmed  the  failure  of  Lebon,  so  that  it  was  universally 
considered  impossible  to  produce  a  practically  useful  gas  from  wood  by  the  usual  process  of 
gas-manufacture.  In  the  year  1849,  Professor  Pettenkofer  of  Munich  had  occasion  to 
repeat  these  experiments,  and  he  found  that  the  gases  evolved  from  wood  at  the  tempera- 
ture at  which  it  carbonizes,  consist  almost  entirely  of  carbonic  acid,  carbonic  oxide,  and 
light  carburetted  hydrogen  ;  defiant  gas  and  the  illuminating  hydrocarbons  being  entirely 
absent.     Such  gas  was  therefore  totally  unfitted  for  illuminating  purposes. 

The  temperature  of  boiling  quicksilver,  at  which  coal  is  not  in  the  slightest  degree  de- 
composed, is  quite  sufficient  to  carbonize  wood  completely.  If  small  pieces  of  wood  be 
placed  in  a  glass  retort  half  filled  with  mercury,  and  the  latter  be  heated  to  boiling,  a  black 
lustrous  charcoal  is  left  in  the  retort,  whilst  gas  of  the  following  composition  is  evolved  : — 

Carbonic  acid 57-4 

Carbonic  oxide 35"6 

Light  carburetted  hydrogen 7  0 

100-0 

If,  however,  the  gases  and  vapors  produced  by  the  above  experiment  be  heated  to  a  con- 
siderably higher  temperature  than  that  at  which  the  wood  is  carbonized.  Professor  Petten- 
kofer found  that  a  very  different  result  is  obtained ;  the  volume  of  permanent  gas  is  con- 
siderably augmented,  whilst  such  an  amount  of  illuminating  hydrocarbons  is  produced  as  to 
render  the  gas  actually  richer  in  these  constituents  than  coal-gas.  Analyses  of  various 
samples  of  such  superheated  gas  gave  the  following  results  : — 

Carbonic  acid 18  to  25  per  cent. 

Carbonic  oxide 40  "  50       " 

Light  carburetted  hydrogen 8  "  12       " 

Hydrogen 14  "  17       " 

Olefiant  gas  and  hydrocarbons 6  "    7       " 

The  illuminating  Value  of  the  hydrocarbons  was  found  to  be  one-half  greater  than  that 
of  an  equal  volume  of  olefiant  gas.  ; 

Varieties  of  wood  differing  so  much  in  character  as  pine  and  beech  were  found  to  yield 
equally  good  gas.  These  observations  prove  that  wood-gas  is  indubitably  entitled  to  rank 
amongst  illuminating  agents. 

With  regard  to  the  apparatus  employed,  various  forms  have  been  contrived  so  as  to 
communicate  the  necessary  temperature  to  the  escaping  vapors :  it  has  been  however  at 
length  found  that  the  ordinary  form  of  retort  furnishes  the  necessary  conditions,  provided 
it  be  not  filled  more  than  one- third  with  the  charge  of  wood.  120  lbs.  of  the  latter, 
thoroughly  dried,  constitute  the  charge  for  one  retort.  In  U  hours  the  distillation  is  com- 
plete, the"  result  being,  after  absorption  of  carbonic  acid,  C50  cubic  feet  of  gas,  which  is 
perfectly  free  from  all  sulphur  and  ammonia  compounds,  and  possesses,  according  to  the 
numerous  experiments  of  Liebig  and  Steinheil,  an  illuminating  power  greater  than  coal-gas 
in  the  proportion  of  6  :  5. 

The  following  analyses  show  the  composition  of  wood-gas  when  made  on  a  manufactur- 
ing scale.  No.  1  is  a  sample  of  gas  before  purification  from  the  works  at  the  Munich  Rail- 
way Station,  and  No.  2  is  purified  gas,  as  supplied  to  the  town  of  Bayreuth  : — 

No.  1.      Olefiant  Gas.        Ko.  2.        Olefiant  Gas. 
Hydrocarbons       .         -         -         -     G-91     =     9.74  7-70     =     11-93 

Light  carburetted  hydrogen  -  11.06  -  -  -  9'45 
Hydrogen  -  -  -  .  -  15-07  -  -  -  18-43 
Carbonic  oxide  -  -  -  -  40-59  -  -  -  61-79 
Carbonic  acid  -  -  -  -  25-72  -  -  -  2-21 
Nitrogen —  ...       -42 

99-35  100-00 

The  specific  gravity  of  the  purified  wood-gas  is  about  -700,  and  this,  coupled  with  the 
lirge  percentage  of  carbonic  oxide  which  it  contains,  renders  it  necessary  to  employ  burn- 


COCHINEAL.  395 

er3  with  much  larger  perforations  than  those  used  for  coal-gas  ;  in  fact,  if  wood-gas  be  con- 
sumed at  the  rate  of  from  3  to  4  cubic  feet  per  hour  from  a  coal-gas  burner,  it  yields 
scarcely  any  light  at  all,  whereas  if  consumed  from  a  fish-tail  burner  with  wide  apertures, 
its  illuminating  power  exceeds,  as  just  stated,  that  of  coal-gas. 

Although  the  relative  cost  of  wood  and  coal  will  prevent  the  adoption  of  Professor  Pet- 
tenkofer's  ingenious  process  in  this  country,  yet,  as  it  can  also  be  applied  with  like  results 
to  peat,  there  is  a  high  probability  that  it  might  bo  employed  witli  great  advantage  in  Ire- 
land. Its  rapid  adoption  in  many  German  and  Swiss  towns  proves  the  practicabihty  of  the 
process  in  districts  where  wood  is  cheap. — E.  F. 

COAL  NAPHTHA.     See  Naphtha  (Coal.) 

COBALT  BLUE,  or  THENARD'S  BLUE,  is  prepared  by  precipitating  a  solution  of 
sulphate  or  nitrate  of  cobalt  by  phosphate  of  potash,  and  adding  to  the  resulting  gelatinous 
deposit  from  three  to  four  times  its  volume  of  freshly  deposited  alumina,  obtained  by  the 
addition  of  carbonate  of  soda  to  a  solution  of  common  alum.  This  mixture,  after  being 
well  dried  and  calcined  in  a  crucible,  affords,  when  properly  ground,  a  beautiful  blue  pig- 
ment. 

COCHINEAL.  In  order  to  ascertain  the  value  of  cochineal  for  dyeing,  we  must  have 
recourse  to  comparative  experiments.  We  are  indebted  to  MM.  Robiquet  and  Anthon  for 
two  methods  of  determining  the  quality  of  cochineals,  according  to  the  quantity  of  carmine 
they  contain.  The  process  of  M.  Robiquet  consists  irt'decolorizing  equal  volumes  of  decoc- 
tion of  different  cochineals  by  chlorine.  By  using  a.  graduated  tube,  the  quality  of  the 
cochineal  is  judged  of  by  the  quantity  of  chlorine  employed  for  decolorizing  the  decoction. 
The  process  of  M.  Anthon  is  founded  on  the  property  which  the  hydrate  of  alumina  pos- 
sesses of  precipitating  the  carmine  from  the  decoction  so  as  to  decolorize  it  entirely.  The 
first  process,  which  is  very  good  in  the  hands  of  a  skilful  chemist,  does  not  appear  to  us  to 
be  a  convenient  method  for  the  consumer  ;  in  the  first  place,  it  is  difficult  to  procure  per- 
fectly identical  solutions ;  in  the  next  place,  it  is  impossible  to  keep  them  a  long  time  with- 
out alteration.  We  know  that  chlorine  dissolved  in  water  reacts,  even  in  diffused  light,  on 
this  liquid ;  decomposes  it,  appropriates  its  elements,  and  gives  rise  to  some  compounds 
which  possess  an  action  quite  ditferent  from  that  of  the  chlorine  solution  in  its  primitive 
state.  The  second  process  seems  to  us  to  be  preferable,  as  the  proof  liquor  may  be  kept  a 
long  while  without  alteration.  A  graduated  tube  is  also  used  ;  each  division  represents  one- 
hundredth  of  the  coloring  matter.  Thus  the  quantity  of  proof  liquor  added  exactly  repre- 
sents the  quantity  in  hundredths  of  coloring  matter  contained  in  the  decoction  of  cochineal 
which  has  been  submitted  to  examination.  The  following  remarks  from  a  practical  dyer  are 
valuable : — 

"  The  coloring  matter  of  cochineal  being  soluble  in  water,  I  have  used  this  solvent  for 
exhausting  the  different  kinds  which  I  have  submitted  to  examination  in  the  colorimeter.  I 
operated  in  the  following  manner: — I  took  a  grain  of  each  of  the  cochineals  to  be  tried, 
dried  at  122^  Fahr. ;  I  submitted  them  five  consecutive  times  to  the  action  of  200  grains  of 
distilled  water  at  water-bath  heat,  each  time  for  an  hour  ;  for  every  200  grains  of  distilled 
water  I  added  two  drops  of  a  concentrated  solution  of  acid  sulphate  of  alumina  and  of  pot- 
ash. This  addition  is  necessary  to  obtain  the  decoctions  of  the  different  cochineals  exactly 
of  the  same  tint,  in  order  to  be  able  to  compare  the  intensity  of  the  tints  in  the  color- 
imeter.* 

"  In  order  to  estimate  a  cochineal  in  the  colorimeter,  two  solutions,  obtained  as  de- 
scribed above,  are  taken ;  some  of  these  solutions  are  introduced  into  the  colorimetric 
tubes  as  far  as  zero  of  the  scale,  which  is  equivalent  to  100  parts  of  the  superior  scale ; 
these  tubes  are  placed  in  the  box,  and  the  tint  of  the  liquids  enclosed  is  compared  by  look- 
ing at  the  two  tubes  through  the  eye-hole  ;  the  box  being  placed  so  that  the  light  falls  ex- 
actly on  the  extremity  where  the  tubes  are.  If  a  difference  of  tint  is  observed  between  the 
two  liquors,  water  is  added  to  the  darkest  (which  is  always  that  of  the  cochineal  taken  as 
type)  until  the  tubes  appear  of  the  same  tint.f 

"  The  number  of  parts  of  liquor  which  are  contained  in  the  tube  to  which  water  has 
been  added  is  then  read  off;  this  number,  compared  with  the  volume  of  the  liquor  con- 
tained in  the  other  tube,  a  volume  which  has  not  Ijcen  changed,  and  is  equal  to  1(»0,  indi- 
cates the  relation  between  the  coloring  power  and  the  relative  quality  of  the  two  cochineals. 
And  if,  for  example,  60  parts  of  water  must  be  added  to  the  liquor  of  good  cochineal,  to 
bring  it  to  the  same  tint  as  the  other,  the  rcl  ition  of  volume  of  the  liquids  contained  in  the 
tubes  will  be  in  the  case  as  160  is  to  100,  and  the  relative  quality  of  the  cochineals  will  lie 
represented  by  the  same  relation,  since  the  quality  of  the  samples  tried  is  in  proportion  to 
their  coloring  power." — {Napier.) 

*  Care  must  bo  taken  not  to  aild  to  the  water,  which  serves  to  extract  the  eoloriiis  iiintter  fniin  the 
(lifforcnt  cochineals,  more  than  the  requisite  quantity  of  acid  sulpliatc  of  alumina  and  .sohition  of  potash, 
because  a  stronfrer  dose  wouhl  precipitate  a  part  of  the  colorin;;  matter  in  tlie  state  of  lake. 

t  For  dilutins  the  liquors  the  same  water  must  alwaj'S  bo  used  which  has  served  to  extract  the  color- 
ins  matter  of  the  cochineals  umler  examination,  otherwise  the  darkest  decoction  would  pass  into  violet, 
as  w.iter  was  added  to  it,  to  bring  back  the  tint  to  the  degree  of  intensity  as  that  of  the  decoction  to 
which  it  is  comi)arcd. 


396  COOK-METAL. 

The  exports  from  Guatemala  consist  principally  of  cochineal,  the  staple  and  almost  the 
only  article  of  exportation  for  a  number  of  years  past.  It  is  chiefly  produced  in  Old  Gua- 
temala, nine  leagues  distant  from  Guatemala,  and  also  in  Amatellan,  about  six  leagues  dis- 
tant. Tlie  raising  of  this  insect  is  subject  to  so  many  accidents  and  contingencies  that  it  is 
excessively  precarious,  and,  above  all,  the  weather  has  a  great  effect  upon  it.  Taking  all 
this  into  consideration,  it  is  sui-prising  that  attention  has  not  been  directed  to  the  cultivation 
and  production  of  other  articles  suited  to  the  climate  and  soil  of  Guatemala,  and  less  liable 
to  destruction  by  unseasonable  rains  and  atmospheric  changes  than  cochineal.  It  is  reason- 
ably to  be  feared  that,  if  a  longer  time  be  suffered  to  pass,  the  cochineal  of  this  country 
caimot  compete  with  that  of  Teneriffe,  and  other  parts  of  the  world,  where  it  is  now  begin- 
ning to  be  cultivated  with  success ;  and,  should  this  happen,  it  would  tend  to  diminish  the 
trade  of  this  country  with  England. 

COCK  METAL.  An  inferior  metal ;  a  mixture  of  copper  and  lead  used  for  making 
cocks.     See  Alloy. 

COCOA-NUT  OIL.  Cocoa-nut  oil  is  obtained  by  two  processes, — one  is  by  pressure, 
the  other  by  boiling  the  bruised  nut  and  skimming  off  the  oil  as  it  forms  on  the  surface. 

It  is  a  white  solid  having  a  peculiar  odor.  It  fuses  a  little  above  70°  Fahr. ;  becomes 
readily  rancid,  and  dissolves  easily  in  alcohol.  It  consists  of  a  solid  fat  called  cocin  or 
cocinine,  (a  combination  of  glycerine  and  cocinic,  or  coco-stearic  acid,)  C"^H^''0'-f- 2H0 ; 
or,  according  to  Richardson,  C'"IP"0'  + Aq,  and  of  a  liquid  fat  or  olcine.  Cocoa-nut  oil  is 
used  in  the  manufacture  of  soap  and  candles. 

COD-LIVER  OIL.  The  oil  obtained  from  the  livers  of  several  varieties  of  the  Gadidm 
family  ;  especially  from  the  torsk,  Brosmitis  brosmc.  It  is  administered  medicinally  :  it  acts 
mainly  as  a  nutritive  body,  and  the  old  idea  that  its  medicinal  value  depended  on  the  iodine 
it  contained  is  now  proved  to  be  false,  since  it  holds  no  iodine  in  composition.  Since  the 
demand  for  cod-liver  oil  has  been  large,  it  lias  been  extensively  adulterated  with  other  fish 
oils. 

CODILLA  OF  FLAX.     The  coarsest  parts  of  the  fibre  sorted  out  by  itslf.     See  Flax. 

COIR.  The  outer  coating  of  the  cocoa-nut,  often  weighing  one  or  two  pounds,  when 
stripped  off  longitudinally,  furnishes  the  fibres  called  by  the  native  name  of  Coir,  and  used 
for  small  cables  and  rigging. 

In  England  these  fibres  are  used  in  matting  and  for  coarse  brush  work.  In  Price  & 
Co.'s  w^rks  they  are  advantageously  employed,  placed  between  iron  trays  and  on  the  sur- 
face of  the  cocoa-nut  and  other  concrete  oils  and  fats,  and  subjected  to  great  pressure  ;  the 
liquid  oil  flows  out,  leaving  solid  fiits  behind.  From  the  abundance,  cheapness,  and  durability 
of  this  substance,  it  is  likely  to  come  into  more  general  use,  and  it  is  even  now  very  seri- 
ously proposed  as  a  material  for  constructing  Ocean  Telegraphs,  from  its  lightness  and  power 
of  resisting  sea-water.  The  qualities  of  coir  for  many  purposes  have  been  established  for  ages 
ill  the  East  Indies.  Dr.  Gilchrist  thus  describes  the  properties  of  coir  ropes  : — "  They  are 
particularly  elastic  and  buoyant,  floating  on  the  surface  of  the  sea ;  therefore,  when,  owing 
to  the  strength  of  the  current,  a  boat  misses  a  ship,  it  is  usual  to  veer  out  a  quantity  of 
coir,  having  previously  fastened  an  oar,  or  small  cask,  &c.,  to  its  end.  Thus  the  boat  may 
be  easily  enabled  to  haul  up  to  the  ship's  stern.  Were  a  coir  hawser,"  he  adds,  "  kept  on 
board  every  ship  in  the  British  Marine,  how  many  lives  would  probably  be  saved." 

It  is  stated  that  fresh  water  rots  coir  in  a  very  short  time,  corroding  it  in  a  surprising 
degree,  whereas  salt  water  absolutely  strengthens  it,  seeming  .to  increase  the  elasticity. 
Coir  is  therefore  unfit  for  running  rigging,  especially  for  vessels  subject  to  low  latitudes,  it 
being  easily  snapped  in  frosty  weather. 

Nothing  can  equal  the  ease  with  which  a  ship  rides  at  anchor,  when  her  cables  are  of 
coir.  As  the  surges  approach  the  bows,  the  vessel  gradually  recedes  in  consequence  of  the 
cable  yielding  to  their  force  ;  but  as  soon  as  they  have  passed,  it  contracts  again,  drawing 
the  vessel  gradually  back  to  her  first  position :  the  lightness  of  the  material  adds  to  this 
effect,  for  the  cable  would  float  if  the  anchor  did  not  keep  it  down.  At  the  present  time 
the  forces  exerted  upon  cables  and  the  angles  assumed  under  different  circumstances,  in 
paying  out  submarine  telegraphic  cables,  have  been  the  subject  of  practical  attention  and 
theoretical  investigation.  Some  of  the  greatest  authorities  have  assumed  that  the  forces 
exerted,  between  the  bottom  of  the  sea  and  the  ship's  stern,  had  reference  only  to  forms  or 
waves  of  the  cables,  representing  some  curve  between  the  vertical  and  horizontal  line,  but 
always  concave  to  the  water  surfiice.  For  a  curve  to  exist,  in  the  opposite  direction,  was 
named  only  as  a  condition,  without  evidence  of  any  practical  kind  to  show  that  it  really 
existed,  or  called  for  any  attention  to  investigate  it.  So  long  since,  however,  as  1825,  Dr. 
Gilchrist,  among  others,  had  described  this  very  opposite  curve  of  the  coir,  viz. — of  being, 
when  in  action  as  a  cable,  curved  with  a  concave  surface  toward  the  bottom  of  the  sea ;  a 
fact  well  known  to  the  experienced  sailors  of  England,  as  well  as  to  the  natives  who  employ 
these  coir  cables  so  extensively  on  the  East  Indian  coast. 

"  A  hempen  cable  always  makes  a  curve  downwards,  between  the  vessel  and  the  anchor, 
but  a  coir  cable  makes  the  curve  upwards.     Therefore,  if  a  right  line  were  drawn  from  the 


COKE.  397 

hawse-hole,  to  the  ring  of  the  anchor,  it  would  be  something  like  the  axis  of  a  parabolic 
spindle,  of  which  the  cables  would  form,  or  nearly  so,  the  two  elliptic  segments." 

In  the  employment  of  materials  for  ocean  telegraphs,  especially  for  deep-sea  purposes, 
the  use  of  iron  and  the  proposal  for  using  coir  and  other  light  substances,  have  caused  the 
telegraphic  means  to  be  spoken  of  as  "  heavy  "  or  "  light "  cables.  Dr.  Allan,  of  Edin- 
buro-h,  proposes  the  abundant  use  of  coir  to  make  a  light  cable,  say  half  the  weight  of  the 
lightest  hitherto  made,  the  Atlantic  cable.  He  states  that  a  deep-sea  cable  may  be  com- 
pounded to  weigh  not  more  than  10  cwt.  per  mile  :  while  the  cheapness,  durability  in  salt 
water,  lightness,  and  abundant  supply,  will  give  it  advantages  over  gutta  percha  and  other 
substances  used  to  form  the  balk  of  the  lightest  cables  hitherto  employed. 

When  cocoa-nuts  are  sawed  into  two  equal  parts  across  the  grain  of  the  coir  coating, 
they  form  excellent  table  brushes,  causing  wood  planks  to  assume  a  very  high  polish  by 
friction.  If  the  shell  should  be  left,  the  edges  should  be  perfectly  smooth,  and  then  they 
will  not  scratch.  It  is  a  good  mode  to  strip  off  the  coir,  and,  after  soaking  it  in  water,  to 
beat  it  with  a  heavy  wooden  mall  until  the  pieces  become  pliant,  when  they  should  be  firmly 
bound  together  with  an  iron  ring  ;  the  ends  being  levelled,  the  implement  is  fit  for  use  ;  a 
little  beeswax,  rubbed  occasionally  upon  them,  adds  greatly  to  the  lustre  of  the  furniture  ; 
of  course,  the  polish  is  mainly  due  to  strength  and  rapid  action  producing  the  friction  upon 
the  wood,  and  other  articles  of  furniture. 

In  India,  the  coarse  bark  of  the  nuts  is  extensively  used  to  cleanse  houses,  and  washing 
the  decks  of  vessels.  Coarse  stuff,  matting,  and  bagging  are  made  of  the  fibres,  as  well  as 
ropes,  sails,  and  cables. 

The  general  preparation  is  simple  ;  the  fibrous  husks  or  coats  which  envelop  the  cocoa- 
nuts,  after  being  for  some  time  soaked  in  water,  become  soft ;  they  are  then  beaten  to  sepa- 
rate other  substances  with  which  they  are  mixed,  which  fall  away  like  saw-dust,  the  strings 
or  fibres  being  left ;  this  is  spun  into  long  yarns,  woven  into  sail-cloth,  and  twisted  into 
cables,  even  for  large  vessels.  Cordage  thus  made  is  considered  preferable,  in  many  re- 
spects, to  that  brought  from  Europe,  especially  the  advantage  of  floating  in  water. 

On  burning  the  ligneous  envelope  of  the  cocoanut,  an  empyreumatic  oil  is  obtained  by 
the  inhabitants  of  the  island  of  Sumatra,  and  used  by  them  for  staining  the  teeth ;  and  a 
light  velvet-like  carbon  which  is  found  useful  in  painting. 

COKE.  (Eng.  and  Fr.  ;  Ab'jexchwcfelte,  Germ.)  It  is  necessary  to  distinguish  between 
what  is  called  gas-coke  and  oven-coke.  The  word  coke  applies,  properly,  to  the  latter 
aloae  ;  for,  in  a  manufacturing  sense,  the  former  is  merely  cinder.  The  production  of  good 
coke  requires  a  combination  of  qualities  in  coal  not  very  frequently  met  with  ;  and  hence 
first-rate  coking  coals  can  be  procured  only  from  certain  districts.  The  essential  requisites 
are,  first,  the  presence  of  very  little  earthy  or  incombustible  ash  ;  and,  secondly,  the  more 
or  less  infusibility  of  that  ash.  The  presence  of  any  of  the  salts  of  lime  is  above  all  objec- 
tionable ;  after  which  may  be  classed  silica  and  alumina ;  for  the  whole  of  these  have  a 
strong  tendency  to  produce  a  vitrification,  or  slag,  upon  the  bars  of  the  furnace  in  which 
the  coke  is  burnt ;  and  in  this  way  the  bars  are  speedily  corroded  or  burnt  out ;  whilst  the 
resulting  clinker  impedes  or  destroys  the  draught,  by  fusing  over  the  interstices  of  the  bars 
or  air-passages.  Iron  pyrites  is  a  common  obstacle  to  the  coke  maker :  but  it  is  found  in 
practice,  that  a  protracted  application  of  heat  in  the  oven  dissipates  the  whole  of  the  sul- 
phur from  the  iron,  with  the  production  of  bisulphuret  of  carbon  and  metallic  carburet  of 
iron,  the  latter  of  which  alone  remains  in  the  coke,  and,  unless  silica  be  present,  has  no 
great  disposition  to  vitrify  after  oxidation.  Where  the  iron  pyrites  exists  in  large  quantities, 
it  is  separated  by  the  coal-washing  machines,  some  of  which  will  be  described  in  a  general 
article. — See  Wasiii.xg  MACfiiNES.  One  object,  therefore,  gained  by  the  oven-coke  manu- 
facturer over  the  gas  maker,  is  the  expulsion  of  the  sulphuret  of  carbon,  and  consequent 
purification  of  the  residuary  coke.  Another,  and  a  still  more  important  consequence  of  a 
long-sustained  and  high  heat  is,  the  condensation  and  contraction  of  the  coke  into  a  smaller 
volume,  which,  therefore,  permits  the  •introduction  of  a  much  greater  weight  into  the  same; 
space — an  advantage  of  vast  importance  in  blast  furanccs,  and,  above  all,  in  locomotive 
engines,  as  the  repeated  introduction  of  fresh  charges  of  coal  fuel  is  thus  prevented.  Part 
of  this  condensation  is  due  to  the  weight  of  the  superincumbent  mass  of  coal  thrown  into 
the  coke-oven,  by  which  (when  the  coal  first  begins  to  cake  or  fuse  together)  the  particles 
are  forced  towards  each  other,  and  the  cavernous  character  of  cinder  got  rid  of:  but  the 
chief  contraction  arises,  as  we  have  said,  from  the  natural  quality  of  carbon,  which,  like 
alumina,  goes  on  contracting,  the  longer  and  higher  the  heat  to  wiiic'h  it  is  expo.sed.  Hence, 
good  coke  cannot  be  made  in  a  short  time,  and  that  used  in  locomotive  engines  is  com- 
'monly  from  48  to  06,  or  even  120  hours  in  tlie  process  of  manufacture. 

The  prospects  of  imjirovement  in  coke-making  point  rather  to  alterations  in  the  oven 
than  in  the  process.  Formerly  it  was  not  thouglit  possil)le  to  utilize  the  heat  evolved  by 
the  gaseous  constituents  of  the  coal ;  but  now,  as  an  example  of  the  incorrectness  of  this 
idea,  it  may  be  stated  that  at  the  Felling  Chemical  Works,  '200  tons  of  salt  per  week  are 
made  by  the  waste  heat  alone,  and  it  is  also  employed  in  partially  heating  the  blast  for  one 


398 


COKE. 


of  the  furnaces.  There  appears  no  valid  reason  why  sets  of  coke-ovens  might  not  be  so 
arranged  as  mutually  to  compensate  for  each  other,  and  produce  upon  one  particular  flue  a 
constant  and  uniform  effect.  Contrivances  of  this  kind  have  been  projected, — but  hitherto 
we  may  suppose,  without  uniform  success,  as  many  of  our  large  coke-makers  still  continue 
the  old  mode  of  working. 

Mr.  Ebenezer  Rogers,  of  Abercam,  in  Monmouthshire,  has  lately  introduced  a  new 
method  of  coking,  which  he  thus  describes  : — 

"  A  short  time  ago  a  plan  was  mentioned  to  the  writer  as  having  been  used  in  Wfest- 
phalia,  by  which  wood  was  charred  in  small  kilns  :  as  the  form  of  kiln  described  was  quite 
new  to  him,  it  led  him  to  some  reflection  as  to  the  principles  on  which  it  acted,  which  were 
found  to  be  so  simple  and  effective,  that  he  determined  to  apply  them  on  a  large  scale  for 
coking  coal.  The  result  has  been  that  in  the  course  of  a  few  months  the  original  idea  has 
been  so  satisfactorily  matured  and  developed,  that  instead  of  coking  6  tons  of  coal  in  an 
oven  costing  £80,  150  tons  of  coal  are  now  being  coked  at  once  in  a  kiln  costing  less  than 
the  former  single  oven. 

"  Figs.  195  and  196  are  a  side  elevation  and  plan  of  one  of  the  new  coking  kilns  to  a 
small  scale  ;  Jig.  197  is  an  enlarged  transverse  section. 


195 


liiii  iinliiiiiiiiiliiiiiiiiiilll  I!  iMMiinnMi 


196 


"  D  D  are  the  walls  of  the  kiln,  which  are  provided  with  horizontal  flues,  e,  f,  which 
open  into  the  side  or  bottom  of  the  mass  of  coal.  Connected  with  each  of  these  flues  are 
the  vertical  chimneys  g  h.  The  dotted  lines  1 1,  fg.  196,  represent  a  movable  railway,  by 
which  the  coal  may  be  brought  into  the  kiln  and  the  coke  removed  from  it.  In  filling  the 
kiln  with  coal,  care  is  taken  to  preserve  transverse  passages  or  flues  for  the  air  and  gases 
between  the  corresponding  flues  e  f  in  the  opposite  walls.  This  is  effected  by  building  or 
constructing  the  passages  at  the  time  with  the  larger  pieces  of  coal,  or  else  by  means  of 
channels  or  flues  permanently  formed  in  the  bed  of  the  kiln.  When  the  coal  is  of  difiVr- 
ent  sizes,  it  is  also  advantageous  to  let  the  size  of  the  pieces  diminish  towards  the  top  of 
the  mass.  The  surface  of  the  coal,  when  filled  in,  is  covered  with  small  coal,  ashes,  and 
other  suitable  material. 

"  When  the  kiln  is  filled,  the  openings  k  at  the  ends  arc  built  up  with  bricks,  as  shown 
dotted  ;  the  kiln  is  not  covered  by  an  arch,  but  left  entirely  open  at  the  top.  The  aper- 
tures of  the  flues  F  and  the  chimneys  g  are  then  closed,  as  shown  in  fg.  197,  and  the  coal 
is  ignited  through  the  flues  e  ;  the  air  then  enters  the  flues  e  and  pa'ss'es  through  the  coal, 
and  then  ascends  the  chimneys  n,  as  shown  by  the  arrows.  When  the  current  of  air  has 
proceeded  in  this  direction  f^or  some  hours,  the  flues  e  and  chimneys  n  are  closed,  and  r 
and  G  are  opened,  which  reverses  the  direction  of  the  current  of  air  through  the  mass. 
This  alternation  of  the  current  is  repeated  as  often  as  may  be  required.     At  the  same  time 


COKE.  399 

air  descends  through  the  upper  surface  of  the  mass  of  coal.  "When  the  mass  is  well  ignited, 
which  takes  place  in  from  24  to  36  hours,  the  external  apertures  of  the  flues  k  and  f  are 
closed,  and  the  chimneys  g  and  ii  opened :  the  air  now  enters  through  the  upper  surface  of 
the  coal  only,  and  descends  through  the  mass  of  the  coal,  the  products  of  combustion  pass- 
ing up  the  chimneys. 

"  The  coking  gradually  ascends  from  the  bottom  of  the  mass  to  the  top,  and  can  be 
easily  regulated  or  equalized  by  opening  or  closing  wholly  or  partially  the  apertures  of  the 
flues  or  chimneys.  The  top  surface  of  the  coal  being  kept  cool  by  the  descending  current 
of  air,  the  workman  is  enabled  to  walk  over  it  during  the  operation  ;  he  inserts  troni  time 
to  time  at  different  parts  of  the  surface  an  iron  bar,  which  is  easily  pushed  down  until  it 
reaches  the  mass  of  coke,  by  which  its  further  descent  is  prevented.  In  this  way  tlie  work- 
man gauges  the  depth  at  which  the  coking  process  is  taking  place,  and  if  he  finds  it  to  have 
progressed  higher  at  one  part  than  at  another,  he  closes  the  chimneys  communicating  with 
that  part,  and  thus  retards  the  process  there.  This  gauging  of  the  surface  is  carried  on 
without  difficulty  until  the  coking  process  has  arrived  close  to  the  top.  The  gases  and  tarry 
vapors  produced  by  the  distillation  or  combustion  descend  through  the  interstices  of  tlie 
incandescent  mass  below,  and  there  deposit  a  portion  of  the  carbon  contained  in  them,  the 
residual  gases  passing  up  the  chimneys.  The  coke  at  the  lower  part  of  the  kiln  is  effect- 
ually protected  from  the  action  of  the  air,  by  being  surrounded  and  enveloped  in  the  gases 
and  vapors  which  descend  through  it,  and  are  non-supporters  of  combustion. 

"  When  the  mass  of  coal  has  been  coked  up  to  the  top,  which  takes  place  in  about  seven 
days,  it  is  quenched  witli  water,  the  walls  closing  the  end  openings  k  are  taken  down,  and 
the  coke  is  removed.  When  a  portion  has  been  removed,  a  movable  railway  is  laid  in  the 
kiln,  so  as  to  facilitate  the  removal  of  the  remainder  of  the  coke. 

"  The  flues  e  and  f  may  enter  at  the  bottom  of  the  kiln,  or  at  the  sides  above  the  bot- 
tom, as  m  Jig.  197  ;  in  the  latter  ease  the  space  below,  up  to  the  level  of  the  bottom  of  the 
flues,  may  be  filled  with  small  coal,  which  becomes  coked  by  the  radiated  heat  from  the 
incandescent  mass  above.  The  transverse  passages  through  the  mass  are  then  constructed 
upon  this  bed  of  small  coal  with  the  larger  lumps  of  coal,  as  before  mentioned.  The  flues 
and  chimneys  need  not  necessarily  be  horizontal  and  vertical ;  and  instead  of  connecting  a 
separate  chimney  with  each  transverse  flue,  flues  may  be  constructed  longitudinally  in  the 
walls  of  the  kiln,  so  as  to  connect  two  or  more  of  the  transverse  flues,  which  are  then  regu- 
lated by  dampers,  conveying  the  gaseous  products  from  them  into  chimneys  of  any  conve- 
nient height ;  the  arrangement  first  described,  however,  and  shown  in  the  drawings,  is  pre- 
ferred. The  gaseous  products  may  be  collected,  and  tar  and  ammonia  and  other  chemical 
compounds  manufactured  from  them  by  the  usual  modes.  The  coking  or  charring  of  peat 
and  wood  may  be  eff'ected  in  a  similar  manner  to  that  already  described  with  regard  to 
coal. 

"  The  new  kilns  have  proved  entirely  successful ;  they  are  already  in  use  at  some  of  the 
largest  iron  works  in  the  kingdom,  and  are  being  erected  at  a  number  of  other  works.  The 
great  saving  in  first  cost  of  oven,  economy  in  working  and  maintenance,  increased  yield,  and 
improved  quality  of  coke,  will  probably  soon  cause  this  mode  of  coking  to  supersede  the 
others  now  in  use.  The  kilns  are  most  advantageously  made  about  14  feet  in  width,  and  90 
feet  in  length,  and  7  feet  6  inches  in  height ;  this  size  of  kiln  contains  about  150  tons  of 
coal." 

From  the  long  experience  of  this  gentleman,  we  are  induced  to  quote  yet  further  from 
his  memoir : — 

"  The  process  of  coking  converts  the  coal  into  a  porous  mass ;  but  this  is  done  during 
the  melting  of  the  coal,  at  which  moment  the  gases  in  liberating  themselves  form  very 
minute  bubbles  ;  but  the  practical  result  is  the  same  as  in  wood  coal,  allowing  a  large  sur- 
face of  carbon  in  a  small  space  to  be  acted  upon  by  the  blast.  As  a  general  rule,  coke 
made  rapidly  has  larger  pores  and  is  lighter  than  coke  made  slowly  ;  it  accordingly  bears 
less  blast,  and  crumbles  too  easily  in  the  furnace. 

"  The  process  of  coking  in  the  ordinary  ovens  may  be  thus  explained :  When  the  oven 
is  filled  with  a  proper  charge,  the  coal  is  fired  at  the  surface  by  the  radiated  heat  from  the 
roof;  enough  air  is  admitted  to  consume  the  gases  given  off  by  the  coal,  and  thus  a  high 
temperature  is  maintained  in  the  roof  of  the  oven.  The  coal  is  by  this  means  melted  ;  and 
those  portions  of  it  which,  under  the  influence  of  a  high  temperature,  can  of  themselves 
form  gaseous  compounds,  are  now  given  off,  forming  at  the  moment  of  their  liberation 
small  bubbles  or  cells  ;  the  coke  now  left  is  quite  safe  from  Wiiste,  unless  a  further  supply 
of  air  is  allowed  to  have  access  to  it.  At  this  stage  of  the  process,  the  coke  assmnes  a  ■ 
'pentagonal  or  five-sided  shape,  and  columnar  structure.  When  the  coke  is  left  exposed  to 
heat  for  some  time  after  it  is  formed,  it  l)ecomcs  harder  and  works  better,  from  being  less 
liable  to  crush  in  the  furnace  and  decrepitate  on  exposure  to  the  blast. 

"  It  has  been  often  remarked  as  a  strange  fact,  that  the  hotter  the  oven  the  better  the 
yield  of  coke  ;  hence  all  the  arrangements  of  flues  to  keep  up  the  temperature  of  the  ovei«. 
This  fact  is  however  the  result  of  laws  well  known  to  chemists     When  the  coal  is  melted  as 


400  COLLIDINE. 

above  mentioned,  the  hydrogen  in  the  coal  takes  up  two  atoms  of  carbon  for  each  two 
atoms  of  hydrogen,  forming  bicarburetted  hydrogen  gas,  (CW  ;)  this  at  once  escapes,  but 
it  has  to  pass  upwards  through  the  red-hot  coke  above,  which  is  at  a  higher  temperature 
than  the  melted  coal  below.  Now  when  bicarburetted  hydrogen  gas  is  exposed  to  a  bright- 
red  heat,  it  is  decomposed,  forming  carburetted  hydrogen  gas,  (CH^,)  and  depositing  one 
atom,  or  one-half  of  its  carbon,  in  a  solid  form.  Consequently  in  the  process  of  coking,  if 
the  oven  is  in  good  working  order  and  the  coke  hot  enough,  the  liberated  carbon  is  detained 
in  its  passage  upwards,  and  either  absorbed  by  the  coke,  or  crystallized  per  se  upon  it. 
This  is  simply  illustrated  by  passing  ordinary  illuminating  gas  through  a  tube  heated  to  a 
bright-red  heat ;  the  tube  will  soon  become  coated  internally,  and  ultimately  filled  with  a 
carbonaceous  deposit  produced  by  the  decomposition  of  the  bicarburetted  hydrogen  con- 
tained in  the  gas. 

"  It  is  found  that  some  coal  which  is  too  dry  or  not  sufficiently  bituminous  to  coke  when 
put  into  the  oven  by  itself  in  lumps,  will  coke  perfectly  if  crushed  small  and  well  wetted 
with  water  and  charged  in  this  state.  This  fact,  if  followed  out,  would  lead  to  an  examina- 
tion of  the  chemical  nature  of  the  effect  produced  by  the  water,  and  would  point  the  way  to 
further  improvements." 

"  Charred  Coal"  as  it  is  called,  must  be  regarded  as  a  species  of  coke.  It  has  been 
largely  employed  in  lieu  of  charcoal  in  the  manufacture  of  tin  plates.  This  preparation  is 
also  a  discovery  of  Mr.  Ebenezer  Rogers,  who  thus  describes  its  manufacture  : — 

The  preparation  of  the  "  charred  coal "  is  simple.  The  coal  is  first  reduced  very  small, 
and  washed  by  any  of  the  ordinary  means ;  it  is  then  spread  over  the  bottom  of  a  rever- 
beratory  furnace  to  a  depth  of  about  four  inches ;  the  bottom  of  the  furnace  is  first  raised  to 
a  red  heat.  When  the  small  coal  is  thrown  over  the  bottom,  a  great  volume  of  gases  is 
given  off,  and  much  ebullition  takes  place  :  this  ends  in  the  production  of  a  slight  spongy 
mass,  which  is  turned  over  in  the  furnace  and  drawn  in  one  hour  and  a  half.  To  com- 
pletely clear  off  the  sulphur,  water  is  now  freely  sprinkled  over  the  mass  until  all  smell  of 
the  sulphuretted  hydrogen  produced  ceases.  Charred  coal  has  been  hitherto  produced  on 
the  floor  of  a  coke-oven,  whilst  red-hot,  after  drawing  the  charge  of  coke.  See  Tin  Plate 
Mancfactcre. 

A  process  has  for  some  time  been  gaining  ground  in  France  known  as  the  "  Si/steme 
Appolt,"  from  its  being  introduced  by  two  brothers  of  that  name.  The  coking  furnaces 
employed  are  vertical,  and  they  are  in  compartments.  The  authors  have  published  a  de- 
scription of  their  process  and  a  statement  of  its  results,  "  Carborusafion  de  la  Houille  Sys- 
teme  Appolt,  dicrit  jmr  les  Aufeurs,  MAT.  Appolt  Freres:"  Paris,  1858,  to  which  we  must 
refer  our  readers. 

COLLIDINE.  C*^H"N.  A  volatile  base  discovered  by  Anderson  in  bone  oil,  and  sub- 
sequently found  in  shale  naphtha,  in  the  basic  fluid  obtained  by  acting  on  ciuchonine  with 
potash,  and  in  common  coal  naphtha.  Its  density  is  0'921,  and  its  boiling  point,  354". — 
C.  G.  W. 

COLORING  MATTERS.  The  color  of  any  object,  either  natural  or  artificial,  owes  its 
origin  to  the  effect  produced  on  it  by  the  rays  of  light.  This  effect  is  either  due  to  the 
mass  or  substance  of  the  body  itself,  as  may  be  seen  in  the  colors  of  metals  and  many 
shells,  or  it  arises  from  the  presence  of  some  foreign  substance  or  substances  not  absolutely 
essential  to  it,  and  which  may  in  many  cases  be  separated  and  removed  from  it.  It  is  in 
speaking  of  these  foreign  substances,  which  are  often  found  coloring  natural  objects,  or 
which  are  employed  in  the  arts  for  the  purpose  of  imparting  colors  to  various  materials, 
that  we  generally  make  use  of  the  term  coloring  mattkr.  By  chemists,  however,  the  term 
is  only  applied  to  organic  bodies  and  not  to  mineral  substances,  such  as  oxide  of  iron,  cin- 
nabar, ultramarine,  &c.,  which,  though  they  are  employed  as  pigments  in  the  arts,  difler 
very  widely  in  their  properties  from  one  another  and  from  coloring  matters  in  the  narrower 
sense  of  the  word.  Coloring  matters  may  be  defined  to  be  substances  produced  in  animal 
or  vegetable  organisms,  or  easily  formed  there  by  processes  occurring  in  nature,  (such  as 
oxidation  or  fermentation,)  and  which  are  either  themselves  colored  or  give  colored  com- 
pounds with  bases  or  with  animal  or  vegetable  fibre.  According  to  this  definition,  bodies 
like  carbazotic  acid  and  murexide,  which  are  formed  by  complicated  processes  such  as  never 
occur  in  nature,  are  excluded,  though  they  resemble  true  coloring  matters  in  many  of  their 
properties,  such  as  that  of  giving  intensely  colored  compound  bases.  Whether,  however, 
even  after  accepting  the  above  definition,  coloring  matters  can  be  considered  as  constituting 
a  natural  class  of  organic  bodies,  such  as  the  fats,  resins,  &c.,  must  still  remain  doubtful, 
though  modern  research  tends  to  prove  that  these  substances  are  related  to  one  another  by 
other  properties  besides  the  accidental  one  of  color,  and  will  probably  be  found  eventually 
to  belong  in  reality  to  one  natural  class. 

Coloring  matters  occur  in  all  the  organs  of  plants,  in  the  root,  wood,  bark,  leaves,  flow- 
ers, and  fruit ;  in  the  skin,  hair,  feathers,  blood,  and  various  secretions  of  animals ;  in 
insects,  for  example,  in  various  species  of  coccus ;  and  in  mollusca,  .such  as  the  murex. 
Indeed,  there  are  very  few  plants  or  animals  whose  organs  do  not  produce  some  kind  of 


COLOKING  MATTERS. 


401 


coloring  matter.  It  is  remarkable,  however,  that  the  colors  which  are  most  frequently  pre- 
sented to  our  view,  such  as  those  of  the  leaves  and  tlowers  of  plants  and  the  blood  of  ani- 
mals, are  produced  by  coloring  matters  with  which  we  are  but  very  httle  acquainted,  the 
coloring  matters  used  in  the  arts,  and  which  have  bpen  examined  with  most  care,  being 
derived  chiefly  from  less  conspicuous  organs,  such  as  the  roots  and  stems  of  plants.  In 
almost  all  cases  the  preparation  of  coloring  matters  in  a  state  of  purity  presents  great  diffi- 
culties, so  that  it  may  even  be  said  that  very  few  are  known  in  that  state. 

Some  coloring  matters  bear  a  great  resemblance  to  the  so-called  extractive  matters,  oth- 
ers to  resins.  Hence  they  have  been  divided  into  extractive  and  resinous  coloring  matters. 
These  resemblances  are  however  of  no  great  importance.  The  principal  coloring  matters 
possess  such  peculiar  properties  that  they  must  be  considered  as  bodies  altogether  sui 
gensris. 

As  regards  their  most  prominent  physical  characteristic,  coloring  matters  are  divided 
into  three  principal  classes,  viz.,  the  red,  yellow,  and  blue,  the  last  class  comprising  the 
smallest  number.  Only  one  true  green  coloring  matter  occurs  in  nature,  viz.,  chlorophyll, 
the  substance  to  which  the  green  color  of  leaves  is  owing.*  Black  and  brown  coloring 
matters  are  also  uncommon,  the  black  and  brown  colors  obtained  in  the  arts  from  animals 
or  vegetables  being  (with  the  exception  of  sepia  and  a  few  others)  compounds  of  coloring 
matters  with  bases.  The  colors  of  natural  objects  are  often  due  to  the  presence  of  more 
than  one  coloring  matter.  This  may  easily  be  seen  in  the  pet.ds  of  some  flowers.  If,  for 
instance,  the  petals  of  the  orange-colored  variety  of  the  Tropmolum  majus  be  treated  with 
lioiling  water,  a  coloring  matter  is  extracted  which  imparts  to  the  water  a  purple  color. 
The  petals  now  appear  yellow,  and  if  they  be  treated  with  boiling  spirits  of  wine,  a  yellow 
coloring  matter  is  extracted,  and  they  then  become  white.  When  the  purple  coloring  mat- 
ter is  absent,  the  flowers  are  yellow ;  when,  on  the  contrary,  it  is  present  in  greater  abun- 
dance, they  assume  different  shades  of  brown.  Precisely  the  same  phenomena  are  observed 
in  treating  the  petals  of  the  brown  Calceolaria  successively  with  boiling  water  and  spirits 
of  wine.  In  many  cases  coloring  matters  exhibit,  when  in  an  uncombined  state,  an  entirely 
different  color  from  what  they  do  when  they  enter  into  a  state  of  combination.  The  color- 
ing matter  of  litmus,  for  instance,  is,  when  uncombined,  red,  but  its  compounds  with  alka- 
lies are  blue.  The  alkaline  compounds  of  alizarine  are  of  a  rich  violet  color,  while  the 
substance  itself  is  reddish-yellow.  Many  yellow  coloring  matters  become  brown  by  the 
action  of  alkalies,  and  the  blue  coloring  matters  of  flowers  generally  turn  green  when  ex- 
posed to  the  same  influence.  The  classification  of  coloring  matters,  according  to  color,  is 
therefore  purely  artificial.  The  terms  red,  yellow,  and  blue  coloring  matter,  merely  signify 
that  the  substance  itself  possesses  one  of  these  colors,  or  that  most  of  its  compounds  are 
respectively  red,  yellow,  or  blue.  In  almost  all  cases,  even  when  the  color  is  not  entirely 
changed  by  combination  with  other  bodies,  its  intensity  is  much  increased  thereby,  sub- 
stances of  a  pale  yellow  color  becoming  of  a  deep  yellow,  and  so  on. 

Coloring  matters  consist,  like  most  other  organic  substances,  either  of  carbon,  hydrogen, 
and  oxygen,  or  of  those  elements  in  addition  to  nitrogen.  The  exact  relative  proportions 
of  these  constituents,  however,  is  known  in  very  few  cases,  and  in  still  fewer  instances  have 
the  chemical  formulae  of  the  compounds  been  established  with  any  approach  to  certainty. 
This  proceeds  on  the  one  hand  from  the  small  quantities  of  these  substances  usually  present 
in  the  organs  of  plants  and  animals,  and  the  difficulty  of  obtaining  sufficient  quantities  for 
examination  in  a  state  of  purity,  and  on  the  other  hand  from  the  circumstance  of  their  pos- 
sessing a  very  complex  chemical  constitution  and  high  atomic  weight. 

Only  a  small  number  of  coloring  matters  are  capable  of  assuming  a  crystalline  form ; 
the  greater  number,  especially  the  so-called  resinous  ones,  being  perfectly  amorphous. 
Among  those  which  have  been  obtained  in  a  crystalline  form,  may  be  mentioned  alizarine, 
indigo-blue,  quercitrine,  morine,  luteoline,  chrysophan,  and  rutine.  It  is  probable,  how- 
ever, that  when  improved  methods  have  been  discovered  of  preparing  coloring  matters,  and 
of  separating  them  from  the  impurities  with  which  they  are  so  often  associated,  many  which 
are  now  supposed  to  be  amorphous  will  be  found  to  be  capable  of  crj'stallizing. 

Very  little  is  known  concerning  the  action  of  light  on  coloring  matters  and  their  com- 
pounds. It  is  well  known  that  these  bodies,  when  exposed  to  the  rays  of  the  sun,  especially 
when  deposited  in  thin  layers  on  or  in  fabrics  made  of  animal  or  vegetable  materials,  lose 
much  of  the  intensity  of  their  color,  and  sometimes  even  disappear  entirely — that  is,  they 
are  converted  into  colorless  bodies.  But  whether  this  process  depends  on  a  physical  action 
induced  by  the  light,  or  whether,  as  is  more  probable,  it  consists  in  promoting  the  decom- 
posing action  of  oxygen  and  moisture  on  them,  is  uncertain.  The  most  stable  coloring  mat- 
ters, such  as  indigo-blue  and  alizarine  in  its  compounds,  are  not  insensible  to  the  action  of 
light.  Others,  such  as  carthamine  from  Safllower,  disappear  rapidly  when  exposed  to  its 
influence.     Colors  produced  by  a  mixture  of  two  coloring  matters  arc  often  found  to  resist 

*  Another  green  coloring  matter,  derived  from  different  epecies  of  lihamnns,  has  lately  been  do- 
scribed  under  the  name  of  "  Chinese  Oreen."  It  is  stated  to  be  a  peculiar  substance,  not,  as  miglit  be 
supposed,  a  mixture  of  a  bh:o  and  a  yellow  coloring  matter. 

YoL.  III.— 26 


402  COLOKING  MATTERS. 

the  action  of  light  better  than  those  obtained  from  one  alone.  In  one  case,  viz.,  that  of 
Tyrian  purple,  the  action  of  light  seems  to  be  absolutely  essential  to  the  formation  of  the 
coloring  matter.  The  leaves  of  plants  also  remain  colorless  if  the  plants  are  grown  in  dark- 
ness, though  in  this  case  the  formation  of  the  green  coloring  matter  is  probably  not  due  to 
the  direct  chemical  action  of  the  light. 

The  action  of  heat  on  coloring  matters  varies  very  much  according  to  the  nature  of  the 
latter  and  the  method  of  applying  the  heat.  A  moderate  degree  of  heat  often  changes  the 
hue  of  a  coloring  matter  and  its  compounds,  the  original  color  being  restored  on  cooling — 
an  effect  which  is  proliably  due  to  physical  causes.  Sometimes  this  effect  is,  without  doul)t., 
owing  to  the  loss  of  water.  Alizarine,  for  instance,  crystallized  from  alcohol,  when  heated 
to  212°  F.,  loses  its  water  of  crystallization,  its  color  changing  at  the  same  time  from  red- 
dish-yellow to  red.  At  a  still  higher  temperature  most  coloring  matters  arc  entirely  decom- 
posed, the  products  of  decomposition  being  those  usually  afforded  by  organic  matters,  such 
as  water,  carbonic  acid,  carburetted  hydrogen,  empyreumatic  oils,  and,  if  the  substance  con- 
tains nitrogen,  ammonia,  or  organic  bases  such  as  aniline.  A  few  coloring  matters,  as,  for 
example,  alizarine,  rubiacine,  indigo-bhie,  and  indigo-red,  if  carefully  heated,  may  be  vola- 
tilized without  change,  and  yield  beautifully  crystallized  sublimates,  though  a  portion  of 
the  substance  is  sometimes  decomposed,  giving  carbon  and  empyreumatic  products. 

Coloring  matters,  like  most  other  organic  substances,  undergo  decomposition  with  more 
or  less  facility  when  exposed  to  the  action  of  oxygen  ;  and  the  process  may,  indeed,  be 
more  easily  traced,  in  their  case,  as  it  is  always  accompanied  ijy  a  change  of  hue.  Its  effects 
may  be  daily  observed  in  the  colors  of  natural  objects  belonging  to  the  organic  world. 
Flowers,  in  many  cases,  lose  a  portion  of  their  color  before  fading.  The  leaves  of  plants, 
before  they  fall,  lose  their  green  color  and  become  red  or  yellow.  The  color  of  venous 
blood  changes,  when  exposed  to  the  air,  from  dark  red  to  light  red.  When  exposed  to  the 
action  of  oxygen,  blue  and  red  coloring  matters  generally  become  yellow  or  brown  ;  but  the 
process  seldom  ends  here  :  it  continues  until  the  color  is  quite  destroyed  ;  that  is,  until  the 
substance  is  converted  into  a  colorless  compound.  This  may  be  easily  seen  when  a  fabric, 
dyed  of  some  fugitive  color,  is  exposed  to  the  air.  The  intensity  of  the  color  diminishes, 
in  the  first  instance  ;  it  then  changes  in  hue,  and,  finally,  disappears  entirely.  Indeed,  the 
whole  process  of  bleaching  in  the  air  depends  on  the  concurrent  action  of  oxygen,  light, 
and  moisture.  The  precise  nature  of  the  chemical  changes  which  coloring  matters  undergo, 
during  this  process  of  oxidation,  is  unknown.  No  doubt  it  consists,  generally  speaking,  in 
the  removal  of  a  portion  of  their  carbon  and  hydrogen,  in  the  shape  of  carbonic  acid  and 
water,  and  the  conversion  of  the  chief  mass  of  the  substance  into  a  more  stable  compound, 
capable  of  resisting  the  further  action  of  oxygen.  But  this  statement  conveys  very  little 
information  to  the  chemist,  who,  in  order  to  ascertain  the  nature  of  a  process  of  decompo- 
sition, requires  to  know  exactly  all  its  products,  and  to  compare  their  composition  with  that 
of  the  substances  from  which  they  are  derived.  The  indeterminate  and  uninteresting  nature 
of  the  bodies  into  which  most  coloring  matters  are  converted  by  oxidation,  has  probably 
deterred  chemists  from  their  examination.  The  action  of  oxygen  on  coloring  matters  varies 
according  to  their  nature  and  the  manner  in  which  the  oxygen  is  applied,  and  it  is  the  de- 
gree of  resistance  which  they  are  capable  of  opposing  to  its  action  that  chiefly  dcteiniines 
the  stability  of  the  colors  produced  by  their  means  in  the  arts.  Indigo-blue  shows  no  ten- 
dency to  be  decomposed  by  gaseous  oxygen  at  ordinary  temperatures  ;  it  is  only  when  the 
latter  is  presented  in  a  concentrated  form,  as  in  nitric  or  chromic  acid,  or  in  a  nascent  state, 
as  in  a  solution  of  ferridcyanide  of  potassium  containing  caustic  potash,  that  it  undergoes 
decomposition.  When,  however,  indigo-blue  enters  into  combination  with  sulphuric  acid, 
it  is  decomposed  by  means  of  oxvgen  with  as  much  facility  as  some  of  the  least  stable  of 
this  class  of  bodies.  Some  coloring  matters  are  capable  of  resisting  the  action  of  oxygen 
even  in  its  most  concentrated  form.  Of  this  kind  are  rubianine  and  rubiacine,  which,  when 
treated  with  boiling  nitric  acid,  merely  dissolve  in  the  liquid,  and  crystallize  out  again  when 
the  latter  is  allowed  to  cool.  The  action  of  atmospheric  oxygen  on  coloring  matters  is  gen- 
erally promoted  by  alkalies,  and  retarded  in  the  presence  of  acids.  A  watery  solution  of 
hematine,  when  mixed  with  an  excess  of  caustic  alkali,  becomes  of  a  beautiful  purple  ;  but 
the  color,  when  exposed  to  the  air,  almost  immediately  turns  brown,  the  hematine  being 
then  completely  changed.  It  is  almost  needless  to  oljserve,  that  the  bodies  into  which 
coloring  matters  are  converted  by  oxidation,  are  incapable,  under  any  circumstances,  of 
returning  to  their  original  state. 

The  action  of  reducing  agents,  that  is,  of  bodies  having  a  great  affinity  for  oxygen,  on 
some  coloring  matters.  Is  very  peculiar.  If  indigo-blue,  suspended  in  water,  be  placed  in 
contact  with  protoxide  of  iron,  protoxide  of  tin,  or  an  alkaline  sulphuret,  sulphite  or  phos- 
phite, or  grape  sugar,  or,  in  short,  any  easily  oxidlzable  body,  an  excess  of  some  alkali  or 
alkaline  earth  being  present  at  the  same  time,  it  dissolves,  forming  a  pale  yellow  solution 
without  a  trace  of  blue.  This  solution  contains,  in  combination  with  the  alkali  or  alkaline 
earth,  a  perfectly  white  substance,  to  which  the  name  of  reduced  ivdir/o  has  been  applied. 
When  an  excess  of  acid  is  added  to  the  solution,  it  is  precipitated  in  white  flocks.     By  ex- 


COLORING  MATTERS.  403 

posure  to  the  air,  either  by  itself  or  in  a  state  of  solution,  reduced  indigo  rapidly  attracts 
oxygen,  and  is  reconverted  into  iudigo-blue.  Hence  the  surface  of  the  solutions,  if  left  to 
stand  in  uncovered  vessels,  becomes  covered  with  a  blue  film  of  regenerated  indigo-blue. 
It  was  for  a  long  time  supposed  that  reduced  indigo  was  simply  deoxidized  indigo-blue,  and 
that  the  process  consisted  merely  in  the  indigo-blue  parting  with  a  portion  of  its  oxygen, 
which  was  taken  up  again  on  exposure  to  the  air.  It  has,  however,  been  discovered,  that 
in  every  case  water  is  decomposed  during  the  process  of  reduction  which  indigo-blue  under- 
goes, the  oxygen  of  the  water  combining  with  the  reducing  agent,  and  the  hydrogen  uniting 
with  the  indigo-blue,  water  being  again  formed  when  reduced  indigo  comes  in  contact  with 
oxygen.  Reduced  indigo  is  therefore  not  a  body  containing  less  oxygen  than  indigo  blue, 
but  is  a  compound  of  the  latter  with  hydrogen.  There  are  several  red  coloring  matters 
which  possess  the  same  property,  that  of  being  converted  into  colorless  compounds  by  the 
simultaneous  action  of  reducing  agents  and  alkalies,  and  of  returning  to  their  original  state 
when  exposed  to  the  action  of  oxygen.  There  can  be  little  doubt  that  the  process  consists, 
in  all  cases,  in  the  coloring  matter  combining  with  hydrogen  and  parting  with  it  again  when 
the  hydruret  comes  in  contact  with  oxygen. 

The  action  of  chlorine  on  coloring  matters  is  very  similar  to  that  of  oxygen,  though,  in 
general,  chlorine  acts  more  energetically.  The  first  effect  produced  by  chlorine,  whether  it 
be  applied  as  free  chlorine,  or  in  a  state  of  combination  with  an  alkali,  or  alkaline  earth  as 
an  hypochlorite,  usually  consists  in  a  change  of  color.  Blue  and  red  coloring  matters  gen- 
erally become  yellow.  By  the  continued  action  of  chlorine,  all  trace  of  color  disappears, 
and  the  final  result  is  the  formation  of  a  perfectly  white  substance,  which  is  usually  more 
easily  soluble  in  water  and  other  menstrua  than  that  from  which  it  was  formed.  Since  it  is 
most  commonly  by  means  of  chlorine  or  its  compounds  that  coloring  matters  are  destroyed 
or  got  rid  of  in  the  arts,  as  in  bleaching  fabrics  and  discharging  colors,  the  process  of  de- 
composition which  they  undergo  by  means  of  chlorine  has  attracted  a  good  deal  of  atten- 
tion, and  the  nature  of  the  chemical  changes,  which  take  place  in  the  course  of  it,  has  often 
been  made  a  subject  of  dispute,  thouglj  the  matter  is  one  possessing  more  of  a  theoretical 
than  a  practical  interest.  It  is  a  well-known  fixct,  that  many  organic  bodies  are  decomposed 
when  they  are  brought  into  contact,  in  a  dry  state,  with  dry  chlorine  gas.  The  decompo- 
sition consists  in  the  elimination  of  a  portion  of  the  hydrogen  of  the  substance  and  its  sub- 
stitution by  chlorine.  When  water  is  present  at  the  same  time,  the  decomposition  is,  how- 
ever, not  so  simple.  It  is  well  known  that  chlorine  decomposes  water,  combining  with  the 
hydrogen  of  the  latter  and  setting  its  oxygen  at  liberty,  and  it  has  been  asserted,  that  in  the 
bleaching  of  coloring  matters  by  means  of  chlorine  when  moisture  is  usually  present,  this  always 
takes  place  in  the  first  instance,  and  that  it  is  in  fact  the  oxygen  which  effects  their  destruc- 
tion, not  the  chlorine.  This  appears,  indeed,  to  be  the  case  occasionally.  Rubian,  for 
instance,  the  body  from  which  alizarine  is  derived,  gives,  when  decomposed  with  chloride 
of  lime,  phthalic  acid,  a  beautifully  crystallized  substance,  containing  no  chlorine,  which  is 
also  produced  by  the  action  of  nitric  acid  on  rubian,  and  is,  therefore,  truly  a  product  of 
oxidation.  In  many  cases,  however,  it  is  certain  that  the  chlorine  itself  also  enters  into  the 
composition  of  the  new  bodies  produced  by  its  action  on  coloring  matters.  When,  for 
instance,  chlorine  acts  on  indigo-blue,  chlorisatine  is  formed,  which  is  indigo-blue,  in  which 
one  atom  of  hydrogen  is  replaced  by  one  of  chlorine,  plus  two  atoms  of  oxygen,  the  latter 
being  derived  from  the  decomposition  of  water. 

The  behavior  of  coloring  matters  towards  water  and  other  solvents  is  very  various. 
Some  coloring  matters,  such  as  those  of  logwood  and  brazilwood,  are  very  easily  soluble  in 
water.  Others,  such  as  the  coloring  matters  of  madder  and  quercitron-bark,  are  only  spar- 
ingly soluble  in  water.  Many,  especially  the  so-called  resinous  ones,  are  insoluble  in'water, 
but  more  or  less  soluble  in  alcohol  and  ether,  or  alkaline  liquids.  A  few,  such  as  indigo- 
blue,  are  almost  insoluble  in  all  menstrua,  and  can  only  be  made  to  dissolve  by  converting 
them,  by  means  of  reducing  agents,  into  other  bodies  soluble  in  alkalies.  Those  which  arc 
soluble  in  water,  are,  generally  speaking,  of  the  greatest  importance  in  the  arts,  since  they 
admit  of  more  ready  application  when  they  possess  this  property. 

The  behavior  of  coloring  matters  towards  acids,  is  often  very  characteristic.  Most 
coloring  matters  are  completely  decomposed  by  nitric,  chloric,  manganic,  and  chromic  acids, 
in  consequence  of  the  large  proportion  of  oxygen  which  these  acids  contain.  With  many 
coloring  matters  the  decomposition  takes  place  even  at  the  ordinary  temperature  ;  with  oth- 
ers, it  only  commences  when  the  acid  is  warmed,  especially  if  the  latter  be  applied  in  a  state 
of  considerable  dilution.  Concentrated  sulphuric  acid  also  destroys  mo.-^t  coloring  matters, 
especially  if  the  acid  be  heated.  It  seems  to  act  by  depriving  them  of  the  elements  of 
water,  and  thereby  converting  them  into  sul>stances  containing  more  carbon  than  before,  as 
may  be  inferred  from  the  dark,  almost  black  color  which  they  acquire.  At  the  same  time 
the  acid  generally  loses  a  portion  of  its  oxygen,  since  sulphurous  acid  is  almost  always 
evolved  on  heating.  Some  coloring  matters,  such  as  alizarine,  are  not  decomposed  by  con- 
centrated sulphuric  acid  even  when  the  latter  is  raised  to  the  boiling  point;  they  merely  dis- 
solve, forming  solutions  of  various  colors,  from  which  they  are  precipitated  unchanged,  on 


40J:  COLORING  MATTERS, 

the  addition  of  water,  when  they  are  insoluble,  or  not  easily  soluble  in  the  latter.  Others, 
a,i;:iin,  like  indigo-blue,  dissolve  in  concentrated  or  fuming  sulphuric  acid,  without  being  de- 
couiposed,  and  at  the  same  time  enter  into  combination  with  the  acid,  forming  true  double 
acids,  which  are  easily  soluble  ia  water,  and  combine  as  such  with  bases.  Many  coloring 
matters  undergo  a  change  of  color  when  exposed  to  the  action  of  acids,  the  original  color 
being  restored  by  the  addition  of  an  excess  of  alkali,  and  this  property  is  made  use  of  for 
the  detection  of  acids  and  alkalies.  The  color  of  an  infusion  of  litmus,  for  instance,  is 
changed  by  acids  from  blue  to  red,  and  the  blue  color  is  restored  by  alkalies.  An  infusion 
of  tlie  petals  of  the  purple  dahlia  or  of  the  violet  becomes  red  on  the  addition  of  acids,  and 
this  red  color  changes  again  to  purple  or  blue  with  alkalies,  an  excess  of  alkali  making  it 
green.  The  yellow  color  of  rutine  becomes  deeper  with  strong  acids.  In  most  cases,  this 
alteration  of  color  depends  on  a  very  simple  chemical  change.  Litmus,  for  example,  in  the 
state  in  which  it  occurs  in  commerce,  consists  of  a  red  coloring  matter  in  combination  with 
ammonia,  the  compound  being  blue.  By  the  addition  of  an  acid,  the  ammonia  is  removed, 
and  the  uncombined  red  coloring  matter  makes  its  appearance.  Ammonia  and  most  alkalies 
remove  the  excess  of  acid,  and,  by  combining  with  the  red  coloring  matter,  restore  the  blue 
color.  When  a  coloring  matter,  like  alizarine,,  is  only  sparingly  soluble  in  water,  its  solu- 
bility is  generally  diminished  in  the  presence  of  a  strong  acid.  Hence,  by  adding  acid  to 
the  watery  solution,  a  portion  of  the  coloring  matter  is  usually  precipitated.  It  is  very  sel- 
dom that  coloring  matters  are  really  found  to  enter  into  combination  with  acids.  Indeed, 
only  one,  viz.,  berberine,  is  capable  of  acting  the  part  of  a  true  base,  and  forming  definite 
compounds  with  acids.  Some  acids,  such  as  sulphurous  and  hydrosulphuric  acids,  do  cer- 
tainly seem  to  combine  with  some  coloring  matters  and  form  with  them  compounds,  in 
wliich  the  color  is  completely  disguised,  and  apparently  destroyed.  If  a  red  rose  be  sus- 
pended in  an  atmosphere  of  sulphurous  acid,^  it  becomes  white^  but  the  red  color  may  be 
restored  by  neutnxlizing  the  acid  with  some  alkali.  On  this  property  of  sulphurous  acid 
depends  the  process  of  bleaching  woollen  fabrics  by  means  of  burning  sulphur.  In  this 
case  the  coloring  matter  is  not  destroyed,  but  only  disguised  by  its  combination  with  the 
acid. 

Most  coloring  matters  are  capable  of  combining  with  bases.  Indeed,  their  afiBnity  for 
the  latter  is  generally  so  marked,  that  they  may  be  considered  as  belonging  to  the  class  of 
weak  acids.  Like  all  other  weak  acids,  they  form,  with  bases,  compounds  of  a  very  indefi- 
nite composition,  so  much  so  that  the  same  compound,  prepared  on  two  different  occasions, 
is  often  found  to  be  differently  constituted.  Hence  the  great  difficulty  experienced  by 
chemists  in  determining  the  atomic  weight  of  coloring  matters.  There  are  very  few  of  the 
latter  for  which  several  formula^  all  equally  probaljle,  may  not  be  given,  if  the  compounds 
with  bases  be  employed  for  their  determination.  The  compounds  of  coloring  matters  with 
bases  hardly  ever  crystallize.  Those  with  alkalies  are  mostly  soluble  in  water  and  amor- 
phous ;  those  with  the  alkaline  earths,  lime  and  baryta,  are  sometimes  soluble,  sometimes 
insoluble  ;  those  with  the  earths  and  metallic  oxides  are  almost  always  insoluble  in  water. 
The  compounds  with  alkalies  are  obtained  by  dissolving  the  coloring  matter  in  water,  to 
wliich  a  little  alkali  is  added,  and  evaporating  to  dryness — an  operation  which  must  be  care- 
fully conducted  if  the  coloring  matter  is  one  easily  aftected  In-  oxygen.  The  insoluble  com- 
pounds, with  earths  and  metallic  oxides,  are  obtiuned  cither  l)y  double  decomposition  of  a 
soluble  compound  with  a  soluble  salt  of  the  respective  base,  or  by  adding  to  a  solution  of 
the  coloring  matter,  in  water  or  any  other  menstruum,  a  salt  of  the  base  containing  some 
weak  acid,  such  as  acetic  acid.  It  is  remarkable,  that  of  all  bases,  none  show  so  much 
affinity  for  coloring  matters  as  alumina,  peroxide  of  iron,  and  peroxide  of  tin,  bodies  which 
occupy  an  intermediate  position  between  acids  and  bases.  If  a  solution  of  any  coloring 
matter  be  agitated  with  a  sufficient  quantity  of  the  hydrates  of  any  of  these  bases,  the  solu- 
tion becomes  decolorized,  the  whole  of  the  coloring  matter  combining  with  the  base  and 
forming  a  colored  compound.  It  is  accordingly  these  bases  that  are  chiefly  employed  in 
dyeing,  for  the  purpose  of  fixing  coloring  matters  on  particular  portions  of  the  fabric  to  lie 
dyed.  When  used  for  this  purpose,  they  are  called  7»or(la?its.  Their  compounds  with 
coloring  matters  are  denominated  lakes,  and  are  employed  as  pigments  by  painters.  The 
colors  of  the  compounds  usually  differ,  either  in  kind  or  degree,  from  those  of  the  coloring 
matters  themselves.  Red  coloring  matters  often  form  blue  compounds,  yellow  ones  some- 
times give  red  or  purple  compounds.  The  compounds  with  peroxide  of  iron  are  usually 
distinguished  by  the  intensity  of  their  color.  When  a  coloring  matter  gives  with  alumina 
and  oxide  of  tin  red  compounds,  its  compound  with  peroxide  of  iron  is  usually  purple  or 
black  ;  and  when  the  former  are  yellow,  the  latter  is  commonly  olive  or  brown.  Almost  all 
the  compounds  of  coloring  matters  with  bases  are  decomposed  by  strong  acids,  such  as  sul- 
phuric, muriatic,  nitric,  oxalic,  and  tartaric  acids,  and  even  acetic  acid  is  not  without  effect 
on  some  of  these  compounds.  The  compounds  with  earths  and  metallic  oxides  are  also 
decomposed,  sometimes,  by  alkalies.  A  solution  of  soap  is  sufficient  to  produce  this  effect 
in  many  cases,  and  dyes  arc  therefore  often  tested  by  means  of  a  solution  of  soap,  in  order 
to  ascertain  the  degree  of  permanence  which  they  possess. 


COLORING  MATTERS.  405 

No  property  is  so  characteristic  of  coloring  matters,  as  a  class,  as  their  behavior  towards 
bodies  of  a  porous  nature,  such  as  charcoal.  If  a  watery  solution  of  a  coloring  matter  be 
agitated  with  charcoal,  animal  charcoal  being  best  adapted  for  the  purpose,  the  coloring 
matter  is  in  general  entirely  removed  from  the  solution  and  absorbed  by  the  charcoal.  The 
combination  wiiich  takes  place  under  these  circumstances  is  probably  not  due  to  any  chemi- 
cal affinity,  but  is  rather  an  effect  of  the  so-called  attraction  of  surface,  which  we  often  see 
exerted  by  bodies  of  a  porous  nature,  such  as  charcoal  and  spongy  platinum,  and  which 
enables  the  latter  to  absorb  such  large  quantities  of  gases  of  various  kinds.  That  the  com- 
pound is  indeed  more  of  a  physical  than  a  chemical  nature,  seems  to  be  proved  by  the  cir- 
cumstance that  sometimes  the  coloring  matter  is  separated  from  its  combination  with  the 
charcoal  by  means  of  boiling  alcohol,  an  agent  which  can  hardly  be  supposed  to  exert  a 
stronger  chemical  affinity  than  water.  It  is  this  property  of  coloring  matters  which  is  made 
use  of  by  chemists  to  decolorize  solutions,  and  by  sugar  manufacturers  to  purify  their  sugar. 
The  attraction  manifested  by  coloring  matters  for  animal  or  vegetable  fibre,  is  probably  also 
a  phenomenon  of  the  same  nature,  caused  by  the  porous  condition  of  the  latter,  and  the 
powerful  affinity  of  the  so-called  mordants  for  coloring  matters,  may,  perhaps,  be  in  part 
accounted  for  by  their  state  of  mechanical  division  being  diflerent  from  that  of  other  bases. 
Coloring  matters,  however,  vary  nmcli  from  one  another  in  their  behavior  -towards  animal 
or  vegetable  fibre.  Some,  such  as  indigo-blue,  and  the  coloring  matters  of  safflower  and 
turmeric,  are  capable  of  combining  directly  with  the  latter  and  imparting  to  them  colors  of 
great  intensity.  Others  are  only  slightly  attracted  by  them,  and  consequently  impart  only 
feeble  tints ;  they  therefore  require,  when  they  are  employed  in  the  arts  for  the  purpose  of 
dyeing,  the  interposition  of  an  earthy  or  metallic  base.  To  the  first  class  Bancroft  applied 
the  term  suh^itanlive  coloring  matters,  to  the  second  that  of  adjeclive  coloring  matters. 

One  of  the  most  interesting  questions  connected  with  the  history  of  coloring  matters,  is 
that  in  regard  to  the  original  state  in  which  these  substances  exist  in  the  animal  and  vege- 
table organisms  from  which  they  are  derived.  It  has  been  known  for  a  long  time  that  many 
dye-stuffs,  such  as  indigo  and  archil,  do  not  exist  ready-formed  in  the  plants  from  which  they 
are  obtained,  and  that  a  long  and  often  difficult  process  of  preparation  is  required  in  order 
to  eliminate  them.  The  plants  which  yield  indigo  exhibit,  while  they  are  growing,  no  trace 
of  blue  color.  The  coloring  matter  only  makes  its  appearance  after  the  juice  of  the  plant 
has  undergone  a  process  of  fermentation.  The  lichens  employed  in  the  preparation  of 
archil  and  litmus  are  colorless,  or  at  most  light  brown,  but  by  steeping  them  in  liquids  con- 
taining ammonia  and  lime,  a  coloring  matter  of  an  intense  red  is  gradually  generated,  which 
remains  dissolved  in  the  alkaline  liquid.  Other  phenomena  of  a  similar  nature  might  be 
mentioned,  as,  for  instance,  the  formation  of  the  so-called  Tyrian  purple  from  the  juice  of  a 
shell-fish,  and  new  ones  are  from  time  to  time  being  discovered.  In  order  to  explain  these 
phenomena,  various  hypotheses  have  been  resorted  to.  It  was  supposed,  for  instance,  that 
the  indigoferaj  contained  white  or  reduced  indigo,  and  hence  were  devoid  of  color,  and  that 
the  process  of  preparing  indigo-blue  consisted  simply  in  oxidizing  the  white  indigo,  which 
was  for  this  reason  denominated  indigof/oie  by  some  chemists.  The  same  assumption  was 
made  in  regard  to  other  coloring  matters,  all  of  which  were  supposed  to  exist  originally  in 
a  deoxidized  and  colorless  state.  In  regard  to  indigo,  however,  the  hypothesis  is  disproved 
at  once  by  the  fact,  that  reduced  indigo  is  only  soluble  in  alkaline  liquids,  and  that  the 
juice  of  the  indigo-bearing  plants  is  always  acid.  In  regard  to  the  other  coloring  matters 
it  seems  also  to  be  quite  untenable.  The  first  person  to  throw  some  light  on  this  obscure 
department  of  organic  chemistry  was  Robiquet.  This  distinguished  chemist  succeeded  in 
obtaining  from  lichens  in  their  colorless  state  a  beautifully  crystallized,  colorless  substance 
soluble  in  water,  having  a  sweet  taste,  and  consisting  of  carbon,  hydrogen,  and  oxygen. 
This  substance  he  denominated  orcine.  By  the  combined  action  of  ammonia  and  oxygen, 
he  found  it  to  be  converted  into  a  red  coloring  matter,  containing  nitrogen,  and  in.'>(olable 
in  water,  which  was  in  fact  identical  with  the  coloring  matter  of  archil.  This  beautiful  dis- 
covery furnished  chemists  with  a  simple  explanation  for  the  curious  phenomena  observed  in 
the  formation  of  tliis  and  other  coloring  matters,  and  it  was  soon  followed  by  others. 
Heeren  and  Kane  oljtained  from  various  lichens  other  colorless  substances  of  similar  prop- 
erties, and  it  was  shown  by  Schunck  that  orcine  is  not  even  the  first  link  in  the  chain,  but 
is  itself  formed  from  another  body,  Iccanorine,  which,  by  the  action  of  alkalies,  yields  orcine 
and  carbonic  acid,  just  as  sugar  by  fermentation  gives  alcohol  and  carbonic  acid.  In  like 
manner,  it  was  discovered  by  Erdmann  that  the  coloring  matter  of  logwood  is  formed  by 
the  simultaneous  action  of  oxygen  and  alkalies  from  a  cr3-stallized  colorless  substance, 
fuema'oxi/lhie,  which  is  the  origiiinl  substance  existing  in  the  wood  of  the  tree,  and  is  like 
'the  others,  not  itself,  strictly  speaking,  a  coloring  matter,  but  a  substance  which  gives  rise 
to  the  formation  of  one. 

There  is,  however,  another  class  of  phenomena  connected  with  the  formation  of  color- 
ing matters,  entirely  different  from  that  just  referred  to.  It  was  discover(>d  by  Robiquet, 
that  if  madder  be  treated  for  some  time  with  sulphuric  acid,  and  the  acid  be  afterwards 
completely  removed,  tlie  madder  is  found  to  have  acquired  a  much  greater  tinctorial  power 


406 


COLZA. 


than  before.  This  fact  was  explained  by  some  chemists  by  supposing  that  the  sulphuric 
acid  had  combined  with  or  destroyed  some  substance  or  substances  contained  in  the  mad- 
der which  had  previously  hindered  the  coloring  matter  from  exerting  its  full  power  in  dye- 
in"  such  as  lime,  sugar,  woody  tibre,  &c.  By  others  it  was  suspected  that  an  actual  forma- 
tion of  coloring  matter  took  place  during  the  process,  and  this  suspicion  has  been  verified 
by  recent  researches.  Schunck  succeeded  in  preparing  from  madder  a  substance  resembling 
gum,  very  soluble  in  water,  amorphous,  and  having  a  very  bitter  taste,  like  madder  itself, 
and  to  which  he  gave  the  name  of  rubian.  This  substance,  though  not  colorless,  is  inca- 
pable of  combining  with  mordants,  like  most  coloring  matters.  When,  however,  it  is  acted 
on  by  strong  acids,  such  as  sulphuric  or  muriatic  acid,  it  is  completely  decomposed,  and 
gives  rise  to  a  number  of  products,  the  most  important  of  which  is  alizarine,  one  of  the 
coloring  matters  of  madder  itself.  Among  the  other  products  are  a  yellow  crystallized 
coloring  matter,  rubiaiiine,  two  amorphous  red  coloring  matters  resembling  resins,  rnhi- 
retine  and  vemntine,  and  lastly,  grape  sugar.  \Yhcn  suVyected  to  fermentation,  the  same 
products  are  formed,  with  the  exception  of  rubianinc,  which  is  replaced  by  a  yellow  color- 
ing matter  of  similar  properties.  This  process  of  decomposition  evidently  belongs  to  that 
numerous  class  called  by  some  chemists  "  catalytic,"  in  which  the  decomposing  agent  docs 
not  act,  as  far  as  we  know,  in  virtue  of  its  chemical  affinities.  It  is  evident,  then,  that  when 
madder  is  acted  on  by  sulphuric  acid,  an  actual  formation  of  coloring  matter  takes  place, 
and  it  is  even  probable  that  the  whole  of  the  coloring  matter  found  in  madder  in  its  usual 
state  was  originally  formed  from  rubian,  by  a  process  of  slow  fermentation,  the  portion  of 
the  latter  still  remaining  undecomposed  being  that  which  is  acted  on  when  acids  are  applied 
to  madder.  From  the  Isatis  tijictoria,  or  common  woad  plant,  Schunck,  in  like  manner, 
extracted  an  amorphous  substance,  easily  soluble  in  water,  called  by  him  iiuUt-av,  and  which, 
by  the  action  of  strong  acids,  is  decomposed  into  imligo-bluc,  indigo-red,  sugar,  and  other 
products,  among  which  are  also  several  resinous  coloring  matters.  Looking  at  them  from 
this  point  of  view,  coloring  matters  may  be  divided  into  two  classes,  viz.,  first,  such  as  are 
formed  from  other  substances,  not  themselves  coloring  matters,  by  the  action  of  oxygen  and 
alkalies  ;  and,  secondly,  such  as  are  formed  from  other  substances  by  means  either  of  fer- 
ments or  strong  acids,  without  the  intervention  of  oxygen.  To  the  first  class  belong  the 
coloring  matters  of  archil,  litmus,  and  logwood  ;  they  yield  comparatively  fugitive  dyes,  and 
are  usually  decomposed  by  allowing  the  very  process  to  which  they  owe  their  formation  to 
continue. "  To  the  second  class  belong  indigo-blue,  indigo-red,  and  alizarine,  bodies  which 
sliow  a  remarkable  degree  of  stability  for  organic  compounds.  More  extended  research  will 
probably  .show  that  many  other  coloring  mattus  are  formed  either  in  one  manner  or  the 
other,  which  will  probably  afford  us  the  means  of  arriving  at  a  rational  mode  of  classifying 
these  bodies,  and  of  distinguishing  them  as  a  class  from  others. — E.  S. 

COLZA.  Colza  oil  is  now  extensively  used  for  burning  in  lamps  dnd  for  lubricating 
machinery.  The  Carcel,  Moderator,  and  other  lamps,  are  contrived  to  give  a  continuous 
supply  of  oil  to  the  wick,  and  by  a  rapid  draught  of  air  brilliant  combustion  of  the  oil  is 
maintained  without  smoke. 

In  the  lighthouses  of  France  and  England  it  has  been  employed  with  satisfaction,  so  as 
to  replace  the  use  of  sperm  oil ;  the  preference  has  been  given  on  the  grounds  of  greater 
brilliancy,  a  steadier  flame,  the  wick  being  less  charred,  and  the  advantage  of  economy  in 
l)rice. 

The  Corporation  of  the  Trinity  House  and  the  late  Mr.  Hume  took  great  interest  in  the 
question  of  the  relative  merits  of  colza,  rape,  and  seed  oils,  as  compared  with  sperm  oil, 
and  in  1845  referred  the  investigation  of  the  power  and  qualities  of  the  light  from  this  de- 
scription of  oil,  to  Professor  Faraday.  He  reported  "  that  he  was  much  struck  with  the 
steadiness  of  the  flame,  Ijurning  12  or  14  hours  without  being  touched;"  "taking  above 
100  experiments,  the  light  came  out  as  one-and-a-half  for  the  seed  oil  to  one  of  the  spenn  ; 
the  quantity  of  oil  being  used  in  the  same  proportion ;"  and  he  concludes  by  stating  his 
"  confidence  in  the  results." 

The  advantages  tlicn  were,  less  trouble,  for  the  lamps  with  sperm  had  to  be  retrimmed, 
and  the  same  lamp  with  seed  oil  gave  more  light,  and  the  cost  then  was  as  3s.  9J.  per  gal- 
lon seed  oil,  against  6.v.  Ad.  imperial  gallon  of  sperm. 

Those  interested  should  consult  returns,  ordered  by  the  House  of  Commons, — "  Ligiit- 
norsKS,  on  the  motion  of  Mr.  Hume,  '  On  the  Substilution  of  Rape  iSeed  Oil  for  Sperm 
Oil,  and  the  Saving  accruing  therefrom:  I7th  Feb.,  1857;  No.  15;  I8th  Jilarch,  1857, 
196  and  196  I." 

In  the  Supplementary  Returns  laid  before  the  House  of  Commons  by  the  Conwiisswner.'i 
of  the  Northern  Ziy/z^s," there  is  the  following  report  of  Alan  Stevenson,  Esq.,  their  En- 
gineer : — 

"  In  the  last  annual  report  on  the  state  of  the  lighthouses,  I  directed  the  attention  of 
the  Board  to  the  propriety  of  making  trial,  at  several  stations,  of  the  patent  culza  or  rape 
seed  oil,  as  prepared  by  Messrs.  Briggs  and  Garford,  of  Bishopsgate  street.  These  trials 
have  now  been  made  during  the  mouths  of  January  and  February,  at  three  catoptric  and 


COMB.  407 

three  dioptric  lights,  and  the  results  have  from  time  to  time  been  made  known  to  me  by 
the  light-keepers,  according  to  instructions  issued  to  them,  as  occasion  seemed  to  require. 
The  substantial  agreement  of  all  the  reports  as  to  the  qualities  of  the  oil  renders  it  needless 
to  enter  into  any  details  as  to  the  slight  varying  circumstances  of  each  case  ;  and  I  have 
therefore  great  satisfaction  in  briefly  stating,  as  follows,  the  very  favorable  conclusion  at 
which  I  have  arrived  : — 

"  1.  The  culza  oil  possesses  the  advantage  of  remaining  fluid  at  temperatures  which 
thicken  the  spermaceti  oil. 

"  2.  The  culza  oil  burns  both  in  the  Fresnel  lamp  and  the  single  argand  burner,  with  a 
thick  wick,  during  seventeen  hours,  without  requiring  any  coaling  of  the  wick,  or 
any  adjustment  of  the  damper ;  and  the  flame  seems  to  be  more  steady  and  free  from 
flickering  than  that  from  spermaceti  oil. 

"  3.  There  seems  (most  probably  owing  to  the  greater  steadiness  of  the  flame)  to  be  less 
breakage  of  glass  chimnej^s  with  the  culzi  than  with  the  spermaceti  oil." 

The  above  firm,  who  from  thirty  years'  experience  in  the  trade  were  enabled  to  induce 
the  Trinity  Corporation  to  give  this  oil  a  fair  and  extended  trial,  state,  that  "  for  manufac- 
turing purposes  it  is  equally  useful ;  it  is  admitted  by  practical  men  to  be  the  best  known 
oil  for  machinery — equal  to  Gallipoli ;  and  technically  it  possesses  more  '  body,'  though 
perfectly  free  from  gummy  matter."     On  this  point,  the  following  letter  has  due  weight : — 

'■^  Admiralti/,  9t/i  December,  1845. — Messrs.  Briggs  and  Garford  : — Referring  to 
your  letter  of  the  1st  of  August  last,  I  have  to  acquaint  you,  in  pursuance  of  the  directions 
of  the  Lords  Commissioners  of  the  Admiralty,  that  the  officers  of  Woolwich  yard  have 
tried  your  vegetable  oil,  and  find  it  to  be  equal  to  the  best  Gallipoli. 

"  It  is  very  hardy  ;  and  while  sperm,  Gallipoli,  nut,  or  lard  oils  arc  rendered  useless  by 
the  slightest  exposure  to  frost,  the  patent  oil  will,  with  ordinary  care,  retain  its  brilliancy : 
this  has  been  acknowledged  as  a  very  important  quality  to  railway  and  steamboat  com- 
panies." 

It  should  be  here  stated,  that  the  terms  rape  oils,  seed  oils,  colza,  or  culza,  are  all  now 
blended  together ;  and,  however  much  this  may  be  regretted,  yet  it  does  not  seem  easy  to 
keep  distinctness  in  the  general  usages  of  oil,  for  the  customs  returns  class  all  under  one 
head, — rape  oil. 

A  number  of  British  and  colonial  seed-bearing  plants  appear  to  be  now  employed  for 
the  sake  of  their  oils,  although,  on  account  of  the  mucilaginous  matter  contained  in  many 
of  the  oils,  they  are  far  inferior  to  the  colza,  which  they  are  employed  to  adulterate. — 
T.  J.  P. 

COMB.  The  name  of  an  instrument  which  is  employed  to  disentangle,  and  lay  parallel 
and  smooth  the  hairs  of  man,  horses,  and  other  animals.  They  are  made  of  thin  plates, 
either  plain  or  curved,  of  wood,  horn,  tortoise-shell,  ivory,  bone,  or  metal,  cut  upon  one  or 
both  sides  or  edges  with  a  series  of  somewhat  long  teeth,  not  far  apart. 

Two  saws  mounted  on  the  same  spindle  arc  used  in  cutting  the  teeth  of  combs,  which 
may  be  considered  as  a  species  of  grooving  process ;  one  saw  is  in  this  case  larger  in  diam- 
eter than  the  other,  and  cuts  one  tooth  to  its  full  depth,  whilst  the  smaller  saw,  separated 
by  a  washer  as  thick  as  the  required  teeth,  cuts  the  succeeding  tooth  part-way  down. 

A  few  years  back,  Messrs.  Pow  and  Lyne  invented  an  ingenious  machine  for  sawing  box- 
wood or  ivory  combs.  The  plate  of  ivory  or  box-wood  is  fixed  in  a  clamp  suspended  on 
two  pivots  parallel  with  the  saw  spindle,  which  has  only  one  saw.  By  the  revolution  of  the 
handle,  a  cam  first  depresses  the  ivory  on  the  revolving  saw,  cuts  one  notch,  and  quickly 
raises  it  again ;  the  handle,  in  completing  its  circuit,  shifts  the  slide  that  carries  the  sus- 
pended clamp  to  the  right,  by  means  of  a  screw  and  ratchet  movement.  The  teeth  are  cut 
with  great  exactness,  and  as  quickly  as  the  handle  can  be  turned ;  they  vary  from  about 
thirty  to  eighty  teeth  in  one  inch,  and  such  is  the  delicacy  of  some  of  the  saws,  that  even 
100  teeth  may  be  cut  in  one  inch  of  ivory.  The  saw  runs  through  a  cleft  in  a  small  piece 
of  ivory,  fixed  vertically  or  radially  to  the  saw,  to  act  as  the  ordinary  stops,  and  prevent  its 
flexure  or  displacement  sideways.  Two  combs  are  usually  laid  one  over  tlie  other  and  cut 
at  once  ;  occasionally  the  machine  has  two  saws,  and  cuts  four  combs  at  once. 

In  the  manufacture  of  tortoise-shell  combs,  very  much  ingenuity  is  disiilaycd  in  solder- 
ing the  back  of  a  large  comb  to  that  piece  which  is  formed  into  teeth.  Tiic  two  jiarts  are 
filed  to  correspond ;  they  are  surrounded  by  pieces  of  linen,  and  inserted  between  metal 
moulds,  connected  at  their  extremities  by  metal  screws  and  nuts ;  tlie  interval  between  the 
halves  of  the  mould  being  occasionally  curved  to  the  sweep  required  in  the  comb;  some- 
times also  the  outer  faces  of  the  mould  are  curved  to  the  particular  form  of  those  combs  in 
■  which  the  back  is  curled  round,  so  as  to  form  an  angle  with  the  teeth.  Tlius  arranged  it  is 
placed  in  boiling  water.  The  joints,  when  properly  made,  cannot  be  detected,  either  bv  the 
want  of  transparency  or  polish.  Much  skill  is  employed  in  turning  to  economical  account 
the  flexibility  of  tortoise-shell  in  its  heated  state :  for  exami)le,  the  teeth  of  the  larger  de- 
scriptions of  comb  are  parted,  or  cut  one  out  of  the  other  with  a  thin  frame  saw  ;  then  the 
sliell,  c<iual  in  size  to  two  combs  with  their  teeth  interlaced,   is  bent  like  an  arch  in  the 


408 


COMBIOTNG  NUMBERS— CHEMICAL  COMBINATION. 


direction  of  the  length  of  the  teeth.  The  shell  is  then  flattened,  the  points  arc  separated 
with  a  narrow  chisel  or  pricker,  and  the  two  combs  are  finished,  whilst  flat,  with  coarse 
single-cut  files,  and  triangular  scrapers ;  and  lastly,  they  are  warmed,  and  bent  on  the  knee 
over  a  wooden  mould  by  means  of  a  strap  passed  round  the  loot,  in  the  manner  a  shoemaker 
fixes  a  shoe-last.  Smaller  combs  of  horn  and  tortoise-shell  are  parted  whilst  flat,  by  an 
ingenious  machine  with  two  chisel-formed  cutters,  placed  oblifiuely,  so  that  every  cut  pro- 
duces one  tooth,  the  repetition  of  which  completes  the  formation  of  the  comb. 

Mr.  Rogers's  comb-cutting  machine  is  described  in  the  Trmisactions  of  the  Society  of 
Ari.-<,  vol.  xlix.,  part  2,  page  loU.  It  has  been  since  remodelled  and  improved  by  Mr. 
Kelly.  This  is  an  example  of  slender  chisel-like  punches.  The  punch  or  chisel  is  in  two 
parts,  filightly  inclined  and  curved  at  the  ends  to  agree  in  form  with  the  outline  of  one  tooth 
of  the  comb,  the  cutter  is  attached  to  the  end  of  a  jointed  arm,  moved  up  and  down  by  a 
crank,  so  as  to  penetrate  almost  through  the  material,  and  the  uncut  portion  is  so  very  tiiin 
that  it  splits  through  it  each  stroke,  and  leaves  the  two  combs  detached. 

Tlie  comb-maker's  double  saw  is  called  a  "  stadda"  and  has  two  blades  contrived  so  as 
to  give  with  great  facility  and  exactness  the  intervals  between  the  teeth  of  combs,  from  the 
coarsest  to  those  having  from  forty  to  forty-five  teeth  to  the  inch.  The  r/ac/e-saw  or  ffoae- 
vid  is  used  to  make  the  teeth  square  and  of  one  depth.  The  saw  is  frequently  made  with 
a  loose  back,  like  that  of  ordinary  back-saws,  but  much  wider,  so  that  for  teeth  -J^  b  f  inch 
long,  it  may  shield  all  the  blade  except  iff  inch  of  its  width  respectively,  and  the  saw  is 
applied  until  the  back  prevents  its  further  progress.  Sometimes  the  blade  has  teeth  on  both 
edges,  and  is  fixed  between  two  parallel  slips  of  steel  connected  beyond  the  ends  of  the  saw 
blade  by  two  small  thumb-screws.  After  the  teeth  of  combs  are  cut,  they  are  smoothed 
and  polished  with  files,  and  by  ruhliing  them  with  pumice  stone  and  tripoli. — Holtzapff'el. 

COMBINING  NUMBERS  AND.  CHEMICAL  COMBINATION.— Constancy  of  compo- 
sition is  one  of  the  most  essential  characters  of  chemical  compounds ;  by  which  is  meant 
that  any  particular  body,  under  whatever  circumstances  it  may  have  been  produced,  consists 
invariably  of  the  same  elements  in  identically  the  same  proportion  ;  the  converse  of  this  \s 
not,  however,  necessarily  true,'  that  the  same  elements  in  the  same  proportion  always  j)ro- 
ducothe^ame  body. 

But  not  only  is  there  a  fixity  in  the  proportion  of  the  constituents  of  a  compound,  but 
also,  if  any  one  of  the  elements  be  taken,  it  is  found  to  unite  with  the  other  elements  in  a 
proportion  which  is  either  invariable,  or  changes  only  by  some  very  simple  multiple. 

Tlie  numbers  expressing  the  combining  projiortions  of  the  elements  are  only  relative. 
In  England  it  is  usual  to  take  hydrogen  as  the  starting  point,  and  to  call  that  number  the 
combhihiff  mimher  of  any  other  element  which  expresses  the  proportion  in  which  it  unites 
with  one  part  by  weight  of  hydrogen;  and  these  numbers  are  now  becoming  adopted  on 
the  Continent,  although  in  France  the  combining  numbers  are  still  referred  to  oxygen, 
which  is  taken  as  100.  It  is  obvious  that,  whichever  system  is  used,  the  numbers  have  the 
■same  value  relatively  to  each  other. 

These  combining  numbers  would  have  but  little  value  if  they  expressed  nothing  more 
than  the  proportion  in  which  the  elements  combine  with  that  body  arbitrarily  fixed  as  the 
standard  ;  but  they  also  represent  the  proportions  in  vliich  they  rinife  amovfi  themselves  in 
the  event  of  nnion  taking  j)lnce.  Thus,  not  only  do  8  parts  of  oxygen  unite  with  one  of 
hydrogen,  but  also  8  parts  of  oxygen  unite  with  SO  of  potas-sium,  23  of  sodium,  100  of 
mercury,  108  of  silver,  &c.  It  is  in  virtue  of  this  law  that  the  combining  proportions  of 
many  of  the  elements  have  been  ascertained.  Some  of  them  do  not  combine  with  hydro- 
gen at  all,  and  in  such  cases  the  cpiantity  which  unites  with  8  parts  of  oxygen,  or  16  of  sul- 
phur, &c.,  has  to  be  ascertained. — H.  M.  W. 

COMBUSTION.  (Eng.  and  Fr.  ;  Verbrenmmr/,  Germ.)  The  phenomena  of  the  de- 
velopment of  light  and  heat  from  any  body,  as  from  charcoal  combining  with  the  oxygen 
of  the  air,  from  phosphorus  comliining  with  iodine,  and  from  some  of  the  metals  combining 
with  chlorine.  Combustion  may  be  exerted  with  very  various  degrees  of  energy.  We  have 
a  low  combustion  often  established  in  masses  of  vegetable  matter ;  as  in  hay-stacks,  or  in 
heaps  of  damp  sawdust.  In  these  cases,  the  changes  going  on  are  the  same  in  character, 
only  varying  in  degree,  as  those  presented  by  an  ordinary  fire,  or  Ijy  a  burning  taper, — 
oxygen  is  combining  with  carbon  to  form  carbonic  acid.  The  heat  thus  produced,  (the 
process  has  been  termed  by  Liebig  Eremacausis,)  increasing  in  force,  gives  rise  eventually 
to  visible  combu.stion. 

COOLING  FLUIDS.     See  Refrigeration  of  Worts. 

COPPER. — 3fcehanical  Preparation  of  the  Copper  Ores  in  Cornteall. — The  ore 
receives  a  first  sorting,  the  object  of  which  is  to  separate  all  the  pieces  larger  than  a  wal- 
nut ;  after  which  the  v^-hole  is  sorted  into  lots,  according  to  their  relative  richness.  The 
fragments  of  poor  ore  are  sometimes  pounded  in  stan)ps,  so  that  the  metallic  portions  may 
be  s(>parated  by  washing. 

The  rich  ore  is  either  Ijroken  into  small  bits,  with  a  flat  beater,  or  by  means  of  a  crush- 
ing-mill.    The  ore  to  be  broken  by  the  bucking-iron  is  placed  upon  plates  of  cast-iron, 


COPPEPw.  409 

each  about  16  inches  square  and  li  inches  thick.  These  plates  are  set  towards  the  edge 
of  a  small  mound  about  a  yard  high,  constructed  with  dry  stones  rammed  with  earth.  The 
upper  surface  of  this  mound  is  a  little  inclined  from  behind  forwards.  The  work  is  per- 
formed by  women,  each  furnished  with  a  bucking-iron  :  the  ore  is  placed  in  front  of  them 
beyond  the  plates ;  they  break  it,  and  strew  it  at  their  feet,  whence  it  is  removed  and  dis- 
posed of  as  may  be  subsequently  required. 

The  crushing-mill  has  of  late  yeais  been  brought  to  a  great  degree  of  perfection,  and  is 
almost  universally  made  use  of  for  pulverizing  certain  descriptions  of  ore.  For  a  descrip- 
tion of  this  apparatus,  see  GRiNniNG  and  Crushimg  Machinery. 

Stamping-mills  are  less  frequently  employed  than  crushers  for  the  reduction  of  copper 
ores.  At  the  Devon  Great  Consols  Mines,  the  concentration  of  the  crushed  copper  ores  is 
effected  in  the  following  manner : — From  the  crushing-mill  the  stuff  is  carried  by  a  stream 
of  water  into  a  series  of  revolving  separating  sieves,  where  it  is  divided  into  fragments  of 
' -20  inch,  '12  inch,  and  Vio  inch  diameter,  besides  the  coarser  particles  which  escape  at  the 
lower  end  of  the  sieves.  The  slimes  flow  over  a  small  water-wheel  called  a  separat(,i\  in 
the  buckets  of  which  the  coarser  portions  settle,  and  are  from  thence  washed  out  by  means 
of  jets  of  water  into  a  round  buddle,  whilst  the  finer  particles  are  retained  in  suspension, 
and  are  carried  off  into  a  series  of  slime-pits,  where  they  are  allowed  to  settle. 

The  ivork  produced  by  the  round  buddle  is  of  three  sorts ;  that  nearest  the  circumfer- 
ence is  the  least  charged  with  iron  pyrites,  or  any  other  heavy  material,  but  still  contains  a 
certain  portion  of  ore  ;  this  is  again  huddled,  when  a  portion  of  its  tail  is  thrown  away,  and 
after  submitting  the  remainder  to  a  huddling  operation,  and  separating  the  ivas/e,  it  is 
jigged  in  a  fine  sieve,  and  rendered  merchantable. 

The  other  portions  of  the  first  buddle  are  rebuddled,  and  after  separating  the  waste,  the 
orey  matters  are  introduced  into  sizing  cisterns,  from  which  the  finer  particles  are  made  to 
flow  over  into  a  buddle,  from  whence  a  considerable  portion  goes  dii-ectly  to  market.  That 
which  requires  further  manipulation  is  again  huddled  until  thoroughly  cleansed.  The 
coarser  portions  of  the  stuff  introduced  into  the  sizing  cisterns  pass  downward  with  a  cur- 
rent of  water  into  the  tye,  and  after  repeated  projections  against  the  stream,  the  orey  mat- 
ter is  separated,  leaving  a  residue  of  mundic  in  a  nearly  pure  state. 

The  stuff  falling  from  the  lower  extremities  of  the  separating  sieves  is  received  into 
bins  and  subsequently  cleansed,  each  of  the  three  sizes  is  jigged,  and  in  proportion  as  the 
worthless  matters  are  separated,  they  are  scraped  off  and  removed.  Those  portions  of  the 
stuff  that  require  further  treatment  are  taken  from  the  sieves,  washed  down  from  behind 
the  hutches,  and  treated  by  tyes,  until  all  the  valuable  portions  have  been  extracted. 

In  this  way,  vein  stuff  that  originally  contained  but  lA-  per  cent,  of  coppei*,  is  so  con- 
centrated as  to  afford  a  metallic  yield  of  10  per  cent.,  whilst,  by  means  of  sizing-eieves, 
dressing-wheels,  jigging-machines,  and  round-buddies,  &c.,  from  40  to  50  tons  of  stuff"  are 
elaborated  per  day  of  9  hours,  at  a  cost  of  12.s.  per  ton  of  dressed  ore. 

Captain  Richards,  the  agent  of  these  mines,  has  also  introduced  considerable  improve- 
ments in  the  slime-dressing  department.  The  proper  sizing  of  slime  is  as  necessary  as  in 
the  case  of  rougher  work,  and  in  order  to  effect  this,  he  has  arranged  a  slime-pit,  which 
answers  tliis  purpose  exceedingly  well.  This  pit  has  the  form  of  an  inverted  cone,  and 
receives  the  slimes  from  the  slime-separator,  in  an  equally  divided  stream.  The  surface  of 
this  apparatus  being  perfectly  level,  and  the  water  passing  through  it  at  a  very  slow  rate, 
all  the  valuable  matters  are  deposited  at  the  bottom.  If  slime  be  valuable  in  the  mass,  it 
can  evidently  be  more  economically  treated  by  a  direct  subdivision  into  fine  and  coarser 
work  ;  since  a  stream  of  water,  acting  on  a  mixture  of  this  kind,  will  necessarily  carry  off 
an  undue  proportion  of  the  former  in  freeing  the  latter  from  the  waste  with  which  it  is  con- 
taminated. 

The  ordinary  slime-pit  is  of  a  rectangular  form,  with  vertical  sides,  and  flat  bottom. 
The  water  enters  it  at  one  of  the  ends  by  a  narrow  channel,  aud  leaves  it  at  the  other.  A 
strong  central  current  is  thus  produced  through  the  pit,  which  not  only  carries  with  it  a 
portion  of  valualile  slime,  but  also  produces  eddies  and  creates  currents  towards  the  edges 
of  the  pit,  and  thus  retains  matters  which  should  have  been  rejected.  The  slime-pits  at 
Devon  Consols  are  connected  with  sets  of  Brunton's  machines,  which  are  thus  kept  regu- 
larly supplied  by  means  "of  a  launder  from  the  apex  of  the  inverted  cone,  through  which 
the  flow  is  regulated  by  means  of  a  plug-valve  and  screw. 

A  wagon  cistern  is  placed  under  each  frame  for  receiving  the  work,  which  is  removed 
when  necessai-y,  and  placed  in  a  packing-kieve.  This  is  packed  by  machinery,  set  in  motion 
-by  a  small  water-wheel.  The  waste  resulting  from  this  operation  is  cither  entirely  rejected, 
or  partially  reworked  on  Brunton's  machines,  whilst  the  orey  matters  contained  in  the  kieve 
are  removed  by  a  wagon  to  the  orehouse,  where  they  are  discharged. 

Napier'x  Process  for  Smcltincf  (Joppcr  Ores. — As  the  copper  ores  of  this  country  often 
contain  small  portions  of  other  metals,  such  as  tin,  antimony,  arsenic,  &c.,  which  are  found 
to  deteriorate  the  copper,  Mr.  Napier's  proer-ss  has  in  view  to  remove  these  metals,  and  at 
the  same  time  to  shorten  the  operations  of  the  smelting  process. 


410  COPPER.   • 

The  first  two  operations,  that  of  calcining  and  fusing  the  ore,  are  the  same  as  the  ordi- 
nary process ;  but  tlie  product  of  this  last  fusion — viz.,  the  coarse  metal — is  again  fused 
with  a  little  sulphate  of  soda  and  coal  mixed.  And  whenever  this  becomes  solid,  after  tap- 
ping the  furnace,  it  is  thrown  into  a  pit  of  water,  where  it  immediately  falls  into  an  impal- 
pable powder ;  the  water  boils,  and  then  contains  caustic  soda  and  sulphide  of  sodium, 
dissolving  from  the  powder  those  metals  that  deteriorate  the  copper,  the  lye  is  let  off,  and 
the  powder  washed  by  allowing  water  to  run  through  it.  The  powder  is  then  put  into  a  cal- 
cining furnace,  and  calcined  until  all  sulphur  is  driven  off,  which  is  easily  done  from  the 
finely  divided  state  of  the  mass.  This  calcined  powder  is  now  removed  to  a  fusing  furnace, 
and  "mixed  with  ores  containing  no  sulphur,  such  as  carbonates  and  oxides,  and  a  little 
ground  coal,  and  the  whole  fused ;  the  result  of  this  fusion  is  metallic  copper  and  sharp 

slao- that  is,  a  scoria  containing  much  protosilicate  of  iron,  which  is  used  as  a  flux  in  the 

firsl  fusion  of  the  calcined  ore,  so  that  any  small  trace  of  copper  which  the  slag  may  con- 
tain is  thus  recovered. 

Tlie  copper  got  from  this  fusion  is  refined  in  the  ordinary  way,  and  is  very  pure. 

When  the  copper  ores  contain  tin  to  the  extent  of  from  4  per  cent,  to  2  per  cent., 
which  many  of  them  are  found  to  do,  Mr.  Napier  proposes  to  extract  this  tin,  and  make  it 
valuable  by  a  process  which  has  also  been  the  subject  of  a  patent.  The  ore  is  first  ground 
and  calcined,  till  the  amount  of  sulphur  is  a  little  under  one-fourth  of  the  copper  present, 
the  ore  is  then  fused  with  a  little  coal.  The  result  of  this  fusion,  besides  the  scoria,  is  a 
regulus  composed  of  sulphur,  copper,  and  iron,  and  under  this  is  a  coarse  alloy  of  copper, 
tin,  and  iron,  called  ichitc  metal.  This  alloy  is  ground  fine,  and  calcined  to  oxidize  the 
metals,  which  are  then  fused  in  an  iron  pot  with  caustic  soda,  which  combines  with  the  tin 
and  leaves  the  copper.  The  oxide  of  copper  is  now  fused  with  the  regulus.  The  stannate 
of  soda  is  dissolved  in  water,  and  the  tin  precipitated  by  slaked  lime,  which  is  dried  and 
fused  with  carbonaceoug  matters  and  a  little  sand,  and  metallic  tin  obtained  ;  the  caustic 
soda  solution  is  evaporated  to  dryness  and  used  over  again.  This  process  is  well  adapted 
for  very  poor  copper  ores  that  are  mixed  with  tin,  or  poor  tin  ores  mixed  with  copper. 

The  Process  of  Extracting  Copper  from  Ores,  at  the  Mines  in  the  Riotinto  District,  Prov- 
ince of  Hitelva,  Spain,  by  ivhat  is  termed  ^''Artificial  Cementation.'''' 
(Translated  from  the  newspaper  "  Minero  Espatiol  "  for  January  23, 1S58.) 

This  method,  which  was  first  applied  here  by  Don  Felipe  Prieto,  a  mine  proprietor  of 
Seville,  in  the  year  1845,  is  the  only  one  employed  in  the  present  day  in  the  copper  mines 
of  that  district. 

The  operation  begins  with  the  calcination  of  the  ores,  previously  reduced  to  small 
pieces ;  piles  or  heaps  of  these  ores  (sometimes  in  the  form  of  cones)  are  made  on  beds  of 
stubble  fire-wood  of  about  a  yard  thick  ;  each  pile  is  made  up  with  from  400  to  500  tons  of 
mineral,  and  allowed  to  burn  for  six  months ;  the  smoke  destroying  all  vegetation  within  its 
reach. 

The  ores,  after  being  thus  burnt  or  calcined,  are  thrown  into  wooden  troughs  let  into 
the  ground, 'about  6  yards  long,  4  wide,  and  1^  deep,  called  "  dissolvcrs."  In  each  of 
these  trouo-hs,  or  cisterns,  are  placed  about  twelve  tons  of  calcined  ore,  and  the  trough  is 
then  filled'^with  water ;  which  water  is,  after  remaining  in  contact  with  the  ores  for  forty- 
eight  hours,  drained  off  into  a  similar  trough  placed  at  a  lower  level,  and  called  a  "  depos- 
itor." The  ores  remaining  in  the  dissolvcr  are  covered  by  a  second  quantity  of  water,  left 
on,  this  time,  for  three  days ;  and  the  process  repeated  four  times  successively,  the  water 
being  alwavs  drained  off  into  the  same  depositor. 

From  the  depositors  the  water  flows  on  to  another  set  of  troughs  called  "  pilones,"  into 
which  is  placed  a  quantity  of  pig  iron,  broken  into  pieces  of  about  the  size  of  bricks,  and 
piled  loosely  together  that  the  vitriol  in  the  water  may  better  act  on  its  whole  surface. 
Each  of  these  troughs  {pilolics)  will  hold  from  12  to  18  tons  of  pig  iron,  (wrought  iron  an- 
swers the  purpose  as  well,  but  it  is  much  more  expensive  ;)  and,  as  experience  has  demon- 
strated that  a  slow  continuous  movement  in  the  water  hastens  the  process,  a  man  is  employed 
for  the  purpose  of  agitating  it,  until  all  the  copper  suspended  in  the  vitriol  water  is  depos- 
ited, which,  in  summer,  is  effected  in  about  2  days,  and  in  from  3  to  5  days  in  winter. 
After  the  water  has  been  renewed  four  or  five  times,  and  the  agitation  process  repeated,  the 
scales  of  copper  deposited  on  the  iron,  as  well  as  that  in  the  form  of  coarse  grains  of  sand 
found  in  the  bottom  of  the  trough,  are  collected  together,  washed,  and  melted,  when  it  is 
found  to  produce  from  65  to  70  per  cent,  of  pure  copper. 

From  the  remains  of  the  first  washings  of  the  above  copper  scales,  &c.,  another  quality 
is  obtained,  worth  about  50  per  cent,  for  copper,  which  is  mixed  with  the  after  washings, 
yielding  about  10  per  cent,  of  copper,  and  passed  on  to  the  smelting  furnace. 

The  method  is  very  defective.  Minerals  containing  5  per  cent,  of  copper,  treated  by 
this  system  of  reduction,  will  scarcely  give  a  produce  of  2  per  cent,  of  that  metal.  It  is, 
however,  the  only  known  method  that  can  be  profitably  employed  in  the  Riotinto  district. 


COPPER. 


411 


l^Notc  by  the  Translator. — The  average  produce  of  the  copper  ores  of  the  Riotinto  dis- 
trict, by  this  process  is  under  14-  per  cent.  The  following  quantities,  put  into  English  meas- 
ure, are  taken  from  the  returns  of  the  Government  mines  at  Riotinto,  published  in  the 
"  Revista  Miuera  :" — 


Tear. 

1 

Quantity  of  Ores 

raised. 

'^''"iio^ducei"''''"          Produce  per  Cent. 

1854 
1855 
1856 

Average    - 

Tons. 
38,915 
37,123 
37,866 

Tons. 
720-9 
834-5 
740-5 

1-85 
2-24 
1-98 

37,968 

765.3 

*2-0  of  4  years. 

The  produce  of  some  of  the  mines  of  the  district  is  under  1  per  cent.  A  quantity  of 
the  richest  of  the  copper  ores  produced  by  the  mines  in  the  Riotinto  district  in  the  year 
1857  has  been  shipped  from  Huelva,  a  port  near  Seville,  for  Newcastle,  in  England  ;  and 
it  has  been  reported  here  that  the  value  of  the  sulphur  saved  in  the  process  of  reduction 
has  contributed  largely  towards  paying  the  smelting  expenses. — S.  H.] 

Tlie  Process  of  Exlrncting  Copper  from  the  Water  that  Drains  out  of  the  Mine  at  Hlo- 
tinto,  called  the  '■'' Si/stem  of  Natural  Cementation^''  (Precipitation.) 

(Translated  frona  the  "  Minero  Espafiol"  for  January  28^  1S58.) 

The  mine  worked  by  the  Spanish  Government  at  Riotinto  is  formed  in  a  mass  of  iron 
pyrites  containing  copper  ;  and  its  immense  labyrinth  of  excavations  are  known  to  extend 
over  a  length  of  500  yards  and  a  width  of  100  yards,  (and  probably  to  a  much  greater  ox- 
tent  ;)  the  earliest  of  which  workings  must  date  back  to  very  remote  times ;  for  in  the  dif- 
ferent excavations  are  still  to  be  found  the  impressions  of  hands,  evidently  guided  by  the 
science  of  the  ancients,  middle  ages,  and  of  more  modern  times. 

The  sixth,  or  lowest  level  in  the  mine,  where  all  the  operations  of  the  present  day  are 
carried  on  is  80  yards  deep,  (from  the  top  of  the  hill  in  which  the  lode  is  found,)  and  it  is 
from  this  level  that  the  mine  is  (naturally)  drained  by  an  adit.  From  the  roof,  at  the  ex- 
treme end  of  a  gallery  at  this  level,  flows,  from  an  unknown  source,  a  stream  of  water  rich 
in  copper,  which,  together  with  the  drain-age  from  other  points  of  the  mine,  is  directed 
through  a  channel  to  the  adit  "  San  Roquo,"  that  empties  its  waters  at  the  foot  of  the  hill, 
where  the  copper  is  extracted. 

An  able  engineer  has  thus  explained  the  phenomena  of  "natural  cementation" : — "  The 
natural  ventilation  through  the  open  excavations  of  this  mine,  combined  with  the  humidity 
of  the  ground,  produces  a  natural  decomposition  of  the  materials  composing  the  lode  or 
vein,  and  thereby  forming  sulphates  of  iron  and  copper,  which  the  water  is  continually  dis- 
solving and  carrying  off,  thus  forming  the  substance  of  this  '  natural  cementation.' " 

This  said  adit  "  San  RoquCj"  which  empties  its  waters  on  the  south  side  of  the  hill,  has 
placed  in  it  two  wooden  launders,  or  channels,  about  12  inches  wide  and  15  inches  deep, 
and  (in  the  year  1853)  400  yards  long  ;  in  the  bottom  of  these  launders  are  placed  pieces  of 
pig  iron,  and  to  this  iron  adhere  the  particles  of  copper  which  the  slowly  flowing  water  con- 
tained in  solution.  In  ten  days  the  iron  becomes  coated  with  copper,  so  pure  as  to  be 
worth  80  per  cent,  for  fine  copper,  and  so  strongly  formed  in  scales  as  to  resist  to  a  certain 
extent  the  action  of  a  file,  and  give  a  strong  metallic  sound  on  being  struck  with  a  hammer. 
At  the  expiration  of  ten  days  or  earlier,  the  scales  of  copper  so  formed  on  the  iron  are 
removed,  that  the  surface  of  the  iron  may  be  again  exposed  to  the  action  of  the  mineral 
water ;  and  the  process  repeated  to  the  entire  extinction  of  the  iron.  The  copper  thus  ob- 
tained passes  at  once  to  the  refining  furnace. 

Since  1853  it  has  been  discovered  that  the  water  escaping  from  the  launders  in  the  adit, 
400  yards  long,  still  contained  copper,  and  they  have  been  lengthened  to  nearly  1,000  yards 
with  good  effect. 

[Note  6y  the  Translator. — The  "  Revista  Mmera,"  (a  mining  review,)  published  by  the 
engineers  of  the  Government  School  of  Mines,  in  Madrid,  gives  returns  of  tlie  Government 
mines  at  Riotinto  for  the  year  1856  ;  wherein  it  is  stated  tliat  the  ((uantity  of  copper  taken 
out  of  this  mineral  water,  by  "  natural  cementation,"  amounted,  for  the  year,  to  206^  tons. 
— S.  H.] 

♦  But  this  averasc  of  2  per  cent  for  tlio  4  ycar.s  contains  and  inchulcs  tlic  copper  produced  from  tlio 
wat('r  whicli  drains  out  of  tlie  mine,  and  wliicli  copper,  for  tlie  year  1S5('>,  amounted  to  '2()(')j  tons;  de- 
ductinf?  tliis  quantity  from  the  return,  740^  tons,  for  that  year,  and  the  produce  would  bo  only  1-43  per 
cent,  for  the  ores. 


412  COPPER. 

The  following  processes  for  the  humid  treatment  of  copper  ores  are  described  by  Messrs. 
Phillips  and  Darlington : — * 

Linz  Copper  Frocexs. — "  At  Linz  on  the  Rhine,  and  some  other  localities  in  Germany, 
the  poorer  sulphides  of  copper,  containing  from  2  to  5  per  cent,  of  that  metal,  are  treated 
by  the  following  process  : — 

"  The  ores  coming  directly  from  the  mine,  and  without  any  preliminary  dressing,  are 
first  roasted  in  a  double-soled  furnace,  and  then  taken  to  a  series  of  tanks  sunk  in  the 
ground,  and  lined  with  basalt.  These  tanks  are  also  provided  with  a  double  bottom,  like- 
wise formed  of  basalt,  so  arranged  as  to  make  a  sort  of  permeable  diaphragm,  and  on  this 
is  placed  the  roasted  ore,  taking  care  that  the  coarser  fragments  are  charged  first,  whilst  the 
finer  particles  are  laid  upon  them. 

"  The  cavity  thus  formed  between  the  bottom  of  the  tank  and  tlie  diaphragm,  or  false 
bottom,  is  connected,  by  means  of  proper  fluos,  with  a  scries  of  oblong  retorts,  through 
each  of  which  a  current  of  air  is  made  to  pass  from  a  ventilator,  or  a  j^air  of  large  bellows, 
set  in  motion  by  steam  or  water  power. 

"  In  order  to  use  this  apparatus,  a  quantity  of  ore  is  roasted  in  the  reverberatory  fur- 
nace, and  subsequently  placed  in  the  tanks,  taking  care  that  the  first  layer  shall  be  in  a 
coarser  state  of  division  than  those  which  succeed  it. 

"  The  retorts — which  are  formed  of  fire  tiles,  and  about  G  inches  in  height  by  1  foot  in 
width  and  6  feet  in  length — are  now  brought  to  a  red  heat,  charged  with  blende,  and  the 
blast  applied. 

"  The  sulphurous  acid  thus  formed  is  forced  by  the  draught  through  the  flues,  where  it 
becomes  mixed  with  nitrous  fumes,  obtained  from  a  mixture  of  nitrate  of  soda  and  sul- 
phuric acid,  and  ultimately  passes  into  the  chambers  beneath  the  diaphragms  on  which  are 
laid  the  roasted  ores,  which  must  be  previously  damped  by  the  addition  of  a  little  water,  of 
which  a  small  quantity  is  also  placed  in  the  bottoms  of  the  tanks.  The  sulphuric  acid  thus 
generated  attacks  the  oxide  of  copper  formed  during  the  preliminary  roasting,  giving  rise 
to  the  production  of  sulphate  of  copper,  which  percolates  through  the  basaltic  diaphragm 
into  the  reservoir  beneath. 

"  The  liquors  which  thus  accumulate  are  from  time  to  time  distributed  over  the  surface 
of  the  ore,  and  the  operation  repeated  until  the  greater  portion  of  the  copper  has  been  ex- 
tracted, when,  by  shifting  the  damper,  the  gases  are  conducted  into  another  tank  similarly 
arranged.  The  liquors  from  the  first  basin  are  now  pumped  into  the  .second,  and  the  opera- 
tion continued  until  the  ores  which  it  contains  have  ceased  to  be  acted  on  by  the  acid. 
When  sufficiently  saturated,  the  liquors  are  drawn  off  into  convenient  troughs,  and  the  cop- 
per i)recipitated  by  means  of  scrap  iron.  The  sulphate  of  iron  thus  formed  is  subsequently 
crystallized  out,  and  packed  into  casks  for  sale. 

"  On  removing  the  attacked  ores  from  the  tank,  the  finer  or  upper  portions  are  thrown 
away  as  entirely  exhausted,  nearly  the  whole  of  the  copper  having  been  removed  from 
them,  whilst  the  coarser  fragments  are  crushed  and  re-roasted,  and  finally  form  the  upper 
stratum  in  a  subsecpient  operation. 

"  It  has  l>cen  found  that,  by  operating  in  this  v,ay,  ores  yielding  only  1  per  cent,  of  cop- 
per may  be  treated  with  considerable  advantage,  since  the  sulphate  of  iron  produced,  and 
the  increased  value  of  the  roasted  blende,  are  alone  sufficient  to  cover  the  expenses  of  the 
operation. 

"  By  this  process,  C  cwt.  of  coal  are  said  to  l)e  required  to  roast  one  ton  of  ore,  whil.-t 
the  same  quantity  of  blende  is  roasted  by  an  expenditure  of  4  cwts.  of  fuel." 

Treatment  of  Copper  Ores  hi/  Jlydroehloric  Acid. — "  At  a  short  distance  from  the  vil- 
lage of  Twista,  in  the  Waldcck,  several  considerable  bands  of  sandstone,  more  or  less  im- 
pregiuated  with  green  carbonate  of  copper,  have  been  long  known  to  exist.  Although  vary- 
ing considerably  in  its  produce,  this  ore,  on  the  average,  yields  2  per  cent,  of  copper,  and 
was  formerly  raised  and  smelted  in  large  quantities  ;  but  this  method  of  treatment  not  hav- 
ing apparently  produced  satisfactory  results,  the  operations  were  ultimately  abandoned. 

"  The  insoluble  natiu-e  of  the  granular  quartzitic  gangue  with  which  the  copper  is  asso- 
ciated, suggested,  some  two  years  since,  to  Mr.  llhodius,  of  the  Linz  Jlctallurgic  Works,  the 
possibility  of  treating  these  ores  by  means  of  hydrochloric  acid,  and  a  large  estabtishment 
for  this  purpose  has  ultimately  been  the  result. 

"  These  works  consist  of  a  crushing  mill,  for  the  reduction  of  the  cupreous  sandstone  to 
a  small  size,  10  dissolving  tubs,  and  a  considerable  nuniljir  of  tanks  and  reservoirs  for  the 
reception  of  the  copper  liquors  and  the  precipitation  of  the  metal  by  means  of  scrap  iron. 
Each  of  the  16  dissolving  tubs  is  13  feet  in  diameter,  and  4  feet  in  depth,  and  furnished 
with  a  large  wooden  revolving  agitator,  set  in  motion  by  a  run  of  overhead  shaftir.g  in  con- 
nection with  a  powerful  water-wlicel.  This  arrangement  admits  of  the  daily  treatment  of 
20  tons  of  ore,  and  the  consequent  production  of  from  7  to  8  cwts.  of  copper.  Each  oper- 
ation is  completed  in  24  hours,  the  liquor  being  removed  from  the  tanks  to  the  precipitating 
trough  by  the  aid  of  wooden  pumps.  The  ore  is  sloped  and  brought  into  the  works  at  4s. 
per  ton. 

*  Kooorils  of  Mining  and  Metallurgy,  p.  1S2. 


COPPER. 


413 


"  The  acid  employed  at  Twista  is  obtained  from  the  alkali  works  in  the  neighborhood  of 
Frankfort,  contains  16  per  cent,  of  real  acid,  and  costs,  delivered  at  the  works,  2s.  per 
100  lbs.  Each  ton  of  sandstone  treated  requires  400  lbs.  of  acid,  which  is  diluted  with 
water  down  to  10  per  cent,  before  being  added  to  the  ore.  Every  ton  of  copper  precipi- 
tated requires  1^  ton  of  scrap  iron  at  £4  5.?.  per  ton. 

"  These  works  yielded  during  the  last  year  120  tons  of  metallic  copper,  and  afforded  a  net 
profit  of  nearly  50  per  cent.  The  residues  from  the  washing  vats,  run  off  after  the  opera- 
tion, contain  but  Vio  per  cent,  of  copper. 

"  It  is  probable  that  this  extremely  simple  process  of  treating  the  poorer  carbonates  and 
oxides  of  copper  may  be  practicable  in  many  other  localities;  but  in  order  to  be  enabled  to 
do  so  with  advantage,  it  is  necessary  that  the  ore  should  be  obtainable  in  large  quantities  at 
a  cheap  rate,  and  that  it  siiould  contain  but  little  lime  or  any  other  substance  than  the  ores 
of  copper  soluble  in  dilute  liydruchloric  acid.  It  is  also  essential  that  the  mine  should  be 
in  the  vicinity  of  alkah  works,  in  order  that  a  supply  of  acid  may  be  obtained  at  a  cheap 
rate,  and  also  that  scrap  iron  be  procurable  in  suflBcient  quantities  and  at  a  moderate  price." 

Assay  of  Copper  Ores. 

The  ores  of  this  metal  are  exceeding  numerous,  but  may  be  comprehended  under  three 
classes : — 

The  /?r.s<  class  includes  those  ores  which  contain,  with  the  exception  of  iron,  no  metal 
except  copper,  and  are  free  from  arsenic  and  sulphur. 

The  second  class  comprehends  those  ores  which  contain  no  other  metal  than  copper  and 
iron,  but  in  which  a  greater  or  less  proportion  of  sulphur  is  present. 

The  third  class  consists  of  such  ores  as  contain  other  metals  in  addition  to  iron  and  cop- 
per, together  with  sulphur  or  arsenic,  or  both. 

The  apparatus  best  adapted  for  the  assay  of  copper  ores  is  a  wind  furnace,  about  16 
inches  in  depth,  and  of  which  the  width  may  be  8  inches,  and  the  length  10  inches.  This 
must  be  supplied  with  good  hard  coke,  broken  into  fragments  of  about  the  size  of  a  small 
orange. 

Ores  of  the  First  Class. — When  these  are  moderately  rich,  their  assay  offers  no  diffi- 
culty, and  usually  affords  satisfactory  results.  The  sample,  after  being  ground  in  a  mortar 
and  well  mixed  to  insure  uniformity  of  composition,  is  intimately  blended  with  three  times 
its  weight  of  black  flux.  The  whole  is  now  introduced  into  a  crucible,  of  which  it  should 
not  occupy  above  one-third  the  capacity,  in  order  to  avoid  loss  from  the  subsequent  swell- 
ing of  the  pasty  mass  when  heated  ;  and  on  the  top  is  uniformly  spread  a  thin  layer  of  car- 
bonate of  soda. 

The  crucible  and  its  contents  arc  now  placed  in  the  furnace,  previously  heated  to  red- 
ness, and  the  pot  is  allowed  to  remain  uncovered  until  th(^re  and  flux  have  become  re- 
duced to  a  state  of  tranquil  fusion.  This  will  take  place  in  the  course  of  about  a  quarter 
of  an  hour,  and  the  crucible  is  then  closed  by  a  co^er,  and  the  damper  opened  so  as  to 
subject  the  assay,  during  another  quarter  of  an  hour,  to  the  highest  temperature  of  the 
furnace.  The  crucible  is  then  removed  from  the  fire,  and  the  metallic  button  obtained, 
either  by  rapid  pouring  into  a  mould,  or  by  allowing  the  pot  to  cool,  and  then  break- 
ing it. 

The  metallic  '■'■  j^rill "  thus  obtained,  may  subsequently,  if  necessary,  be  refined  accord- 
ing to  the  Cornish  process,  to  be  hereafter  described. 

Ores  of  the  Second  Class. — The  most  common  ores  of  this  class  are  copper  pyrites  and 
other  sulphides. 

Fusion  for  Regiilus. — This  process  consists  in  fusing  the  ores  with  fluxes  capable  of 
removing  a  portion  of  its  sulphur,  and  eliminating  siliceous  and  earthy  impurities.  These 
conditions  are  well  fulfilled  by  a  mixture  of  nitre  and  borax,  since,  with  a  proper  propor- 
tion of  these  reagents,  all  the  ores  belonging  to  this  class  are  fused  with  the  formation  of  a 
vitreous  slag  and  a  well-formed  button  of  regulus.  When  the  contents  of  the  crucible  have 
been  completely  fused,  they  must  be  rapidly  poured  into  an  iron  or  bell-metal  mould  of  a 
conical  form. 

The«separation  of  the  regulus  from  the  scoriaj  must  be  carefully  effected  by  the  use  of 
a  small  chisel-edged  hammer,  a  sheet  of  paper  being  placed  under  the  button  to  prevent 
loss. 

Roasting. — To  obtain  the  pure  metal  from  the  sulphides  of  copper,  it  is  necessary  that 
tlie  sulphur,  &c.,  should  be  removed  by  roasting  before  reducing  the  copper  present  to  the 
metallic  state. 

When  rich  ores,  producing  from  20  to  35  per  cent,  of  metallic  copper,  arc  operated  on, 
the  roasting  and  subsequent  reduction  may  be  made  directly  qu  the  mineral.  When,  how- 
ever, poor  ores,  such  as  those  of  Cornwall,  containing  from  6  to  10  per  cent.,  are  to  be 
treated,  it  is  far  better  to  commence  by  obtaining  a  button  of  regulus  as  above. 

The  calcination  of  the  rich  ore  or  regulus  is  conducted  in  the  same  crucible  in  which 
the  subsequent  fusion  with  reducing  agents  is  to  take  place ;  and  at  the  commencement  of 


iU  COPPER. 

tbe  operation  care  must  be  taken  not  to  cause  the  agglutination  of  the  ore,  or  pulverized 
button,  by  the  application  of  too  high  a  temperature.  In  order  to  succeed  in  effecting  this 
object,  the  ore  or  regulus  must  be  first  finely  powdered  in  an  iron  mortar,  and  then  put 
into  an  earthen  crucible,  which  is  to  be  placed  in  a  sloping  position  on  the  ignited  coke 
with  which  the  furnace  is  filled,  the  draught  at  the  same  time  being  partially  cut  off  by  the 
damper. 

A  moderate  heat  is  thus  obtained,  and  the  mixture  is  continually  stirred  by  means  of  a 
slight  iron  rod,  so  that  each  particle  may  in  its  turn  be  exposed  to  the  oxidizing  influences 
of  the  atmosphere.  When  a  large  portion  of  the  sulphur,  &c.,  has  been  driven  off,  the 
contents  of  the  crucible  become  less  fusible,  and  may  without  inconvenience  be  heated  to 
redness.  At  this  stage,  it  is  often  found  advantageous  to  heat  the  partially  roasted  mass 
to  full  redness,  since  by  this  means  the  sulphides  and  sulphates  become  reduced  to  the  state 
of  oxides  by  their  mutual  reaction  on  each  other. 

As  soon  as  the  smell  of  sulphur  can  no  longer  be  observed,  and  the  roasting  process  is 
consequently  in  an  advanced  state,  the  heat  should  for  some  minutes  be  increased  to  white- 
ness, in  order  to  decompose  the  sulphates,  after  which  the  crucible  may  be  withdrawn  and 
allowed  to  cool. 

Reduction. — To  obtain  the  copper  from  the  roasted  ore  or  matt,  it  may  be  mixed  with 
one-fourth  its  weight  of  lime,  from  10  to  20  per  cent,  (according  to  the  produce  of  the  ore) 
of  finely  powdered  charcoal,  from  1  to  1^  times  its  weight  of  soda  ash  or  pearl  ash,  and  a 
little  borax.  When  this  has  been  well  mixed,  it  is  placed  in  the  crucible  in  which  the 
roasting  of  the  ore,  or  regulus,  has  been  conducted,  and  covered  with  a  thin  stratum  of 
fused  borax. 

In  lieu  of  powdered  charcoal,  from  15  to  20  per  cent,  of  crude  tartar  is  sometimes  em- 
ployed. 

The  crucible  is  now  placed  in  the  fire  and  strongly  heated  for  about  a  quarter  of  an 
hour,  at  the  expiration  of  which  time  the  bubbling  of  the  assay  will  have  ceased,  and 
it  must  then  be  closed  by  an  earthen  cover,  and  for  a  short  time  heated  nearly  to  white- 
ness. 

The  prill  may  be  obtained  cither  by  rapidly  pouring  into  a  suitable  mould  or  by  allow- 
ing the  pot  to  cool  and  then  breaking  it.  If  required,  the  resulting  button  may  be  refined 
by  the  Cornish  method. 

Orcf:  of  the  Tliird  Class. — Minerals  belonging  to  this  class  must  be  treated  like  those  of 
the  second,  excepting  that  the  preliminary  roasting  should,  from  their  greater  fusibility,  be 
conducted  at  a  lower  temperature.  The  button  obtained  from  the  calcined  ore,  or  regulus, 
will  in  tliis  case  consist  of  an  alloy  of  copper  and  other  metals  instead  of,  as  in  the  former 
instances,  being  nearly  pure  copper. 

If  an  ore  contains  lead,  the  roasting  must  at  first  be  conducted  with  the  greatest  pre- 
caution, since  it  is  extremely  difficult,  so  to  moderate  the  heat  as  to  cause  at  the  same  time 
the  elimination  of  the  arsenic  and  sulphur,  and  avoid  the  agglutination  of  the  mass. 

The  assay  of  ores  belonging  to  this  class  should  in  all  cases  be  commenced  by  a  fusion 
for  matt. 

The  refining  of  the  button  obtained  from  such  assays  may  he  effected  either  Ijy  the  Cor- 
nish method,  or  by  the  humid  process,  to  be  hereafter  described. 

Cornish  Metliod  of  condKclinrj  an  Assai/. — A  portion  of  the  pounded  and  sifted  ore  is 
first  burnt  on  a  .shovel,  and  examined  as  to  its  supposed  richness  and  the  amount  of  sul- 
phur, arsenic,  and  other  impurities  it  may  contain.  A  little  practice  in  this  operation  will 
enable  the  operator  to  judge  with  considerable  accuracy  of  the  quantity  of  nitre  necessary 
in  order  to  obtain  a  good  regulus. 

Two  hundred  grains  of  the  mixed  ore  are  now  vrcighod  out  and  carefully  mixed  with  a 
flux  consisting  of  nitre,  borax,  lime,  and  fluor-spar,  and  the  fusion  for  matt  or  regulus  is 
begun.  The  quantity  of  nitre  used  will  of  course  vary  with  the  amount  of  sulphur  and  ar- 
senic present ;  but  the  other  ingredients  arc  commonly  employed  in  the  following  propor- 
tions:— Borax,  5  dwts. :  lime,  l^ladlefuls;  fluorspar,  1  ladleful.*  After  being  placed  in 
the  crucible,  the  whole  is  generally  covered  by  a  thin  stratum  of  common  salt.  After  re- 
maining in  the  fire  for  about  a  quarter  of  an  hour,  the  fusion  will  be  found  complete,  and 
tlie  contents  of  the  pot  may  be  poured  into  a  suitable  iron  mould.  The  button  or  regulus 
i.s  now  examined,  in  order  to  determine  whether  a  suital)le  proportion  of  nitre  has  been 
used.  If  the  right  quantity  has  l)een  employed,  the  button,  v.hen  lirok en,  should  present 
a  granular  fracture,  and  yield  from  "  8  to  10  for  20"  for  copper,  i.  c,  from  40  to  50  per 
cent.  However  rank  a  sample  may  Ije,  it  should  never  be  mixed  with  above  9  or  9^  dwts. 
of  nitre ;  and  if  the  amount  of  sulphur  be  small,  3  dwts.  arc  often  sufficient.  The  gray 
sulphides,  the  red  and  black  oxides,  and  carbonates,  have  sulphur  added  to  them  for  the 
purpose  of  obtaining  a  regulus. 

Iliglily  sulphuiizcd  samples,  requiring  above  9^  dwts.  of  nitre,  are  sometimes  treated  in 
a  diflcrent  way. 

*  Tl)e  liiill^!  u.sod  for  tliis  purpose  is  three-quarters  of  an  inch  in  tliameter  nnd  half  an  inch  in  doptli. 


COPPER.  415 

In  this  case  the  ores  are  first  carefully  roasted,  and  afterwards  fused  with  about  5  dwts. 
of  nitre,  9  dwts.  of  tartar,  and  3  dwts.  of  borax. 

The  roasting  of  the  rogulus  thus  obtained  is  performed  in  a  smaller  crucible  than  that 
used  in  the  fusion  for  matt.  During  the  first  quarter  of  an  hour,  a  very  low  temperature  is 
suilicient.  The  heat  is  then  increased  to  full  redness,  and  the  assay  allowed  to  remain  on 
the  fire  for  a  further  period  of  about  20  minutes.  During  the  first  15  minutes  it  should  be 
kt'pt  constantly  stirred  with  a  slender  iron  rod ;  but  afterwards  an  occasional  stirring  will 
be  found  sufficient.  When  nearly  the  whole  of  the  sulphur  and  arsenic  has  been  expelled, 
tlie  temperature  must  be  raised  nearly  to  whiteness  during  a  few  minutes,  and  the  as.^ay 
then  withdrawn  and  allowed  to  cool.  The  fusion  for  copper  is  effected  in  the  same  crucible 
in  which  the  roasting  has  been  carried  on. 

The  quantity  of  flux  to  be  used  for  this  purpose  varies  m  accordance  with  the  weight  of 
the  button  of  regulus  obtained.  A  mixture  of  2  dwts.  of  niti-e,  7+  dwts.  of  tartar,  and  1  V 
dwts.  of  borax,  is  sufficient  for  the  reduction  of  a  calcined  regulus  that,  previous  to  roast- 
ing, weighed  from  45  to  50  grains.  In  the  case  of  a  button  weighing  from  90  to  100  grains, 
3}  dwts.  of  nitre,  9  dwts.  of  tartar,  and  2  dwts.  of  borax,  should  be  employed.  These 
quantities  are,  however,  seldom  weighed,  since  a  little  practice  renders  it  easy  to  guess, 
with  a  sufficient  degree  of  accuracy,  the  necessary  amounts. 

The  prill  of  copper  thus  obtained  is  seldom  fine,  and  consequently  requires  purifica- 
tion. 

A  crucible  is  heated  to  redness  in  the  furnace,  the  metallic  button  is  taken  from  the 
mould  and  thrown  into  it,  and  some  refining  flux  and  salt  are  placed  in  a  scoop  for  imme- 
diate use.*  In  a  few  minutes  the  fusion  of  the  prill  is  effected.  The  crucible  is  now  taken 
from  the  fire  by  a  pair  of  tongs,  the  contents  of  the  scoop  introduced,  and  a  gentle  agita- 
tion given  to  it ;  an  appearance  similar  to  the  brightening  of  silver  on  the  cupel  now  takes 
place,  and  the  crucible  is  returned  to  the  fire  for  about  four  minutes. 

The  crucible  is  now  removed,  and  its  contents  rapidly  poured  into  a  mould.  The  but- 
ton thus  obtained  will  consist  of  pure  copper,  and  present  a  slight  depression  on  its  upper 
surface. 

The  slags  from  the  reducing  and  refining  operations  are  subsequently  fused  with  a 
couple  of  spoonfuls  of  crude  tartar,  and  the  prill  thus  obtained  weighed  with  the  larger 
button. 

Humid  Method  of  assaying  Copper  Ores. — In  some  localities,  and  particularly  in  the 
United  States  of  America,  the  assay  of  copper  ores  is  performed  by  the  humid  process. 
The  whole  of  the  ores  belonging  to  the  three  different  classes  may  be  estimated  in  this 
way: 

A  weighed  quantity  of  the  pulverized  ore  is  introduced  into  a  long-necked  flask  of  hard 
German  glass,  and  slightly  moistened  with  water.  Nitric  add  is  now  added,  and  the  flask 
exposed  to  the  heat  of  a  sand  bath.  A  little  hydrochloric  acid  is  subsequently  introduced, 
and  the  attack  continued  until  the  residue,  if  any  remains,  appears  to  be  free  from  all 
metallic  stains. 

The  contents  of  the  flask  must  be  transferred  to  a  porcelain  evaporating  dish,  and  evap- 
orated to  dryness,  taking  care,  by  means  of  frequent  stirring,  to  prevent  the  mass  from 
s[)iiting.  The  whole  must  now  be  removed  from  the  sand  bath  and  allowed  to  cool,  a  little 
hydrochloric  acid  subsequently  added,  and,  afterwards,  some  distilled  water.  The  contents 
of  the  basin  must  then  be  made  to  boil,  and,  whilst  still  hot,  filtered  into  a  beaker.  A 
piece  of  bright  wrought  iron,  about  two  inches  in  length,  three-quarters  of  an  inch  in  width, 
and  a  quarter  of  an  inch  in  thickness,  is  now  introduced,  and  the  liquor  gently  heated  on 
the  sand  bath  until  the  whole  of  tlic  copper  has  been  thrown  down.  The  liquor  is  iiow  re- 
moved by  means  of  a  glass  siphon,  and  the  metallic  copper  freed  from  all  adhering  chlo- 
rides, by  means  of  repeated  washings  with  hot  water,  and  then  dried  in  a  water  bath,  and 
weighed. 

In  case  the  mineral  operated  on  .should  contain  tin  or  antimony,  very  minute  traces 
only  of  these  metals  will  be  found  with  tlie  precipitated  copper.  AVhen  lead  is  present,  it 
is  best  to  add  a  few  drops  of  sulphuric  acid  during  the  process  of  the  attack  ;  by  this  means 
the  lead  will  be  precipitated  as  sulphate  of  lead,  and  be  removed  by  filtration.  The 
results  obtained  by  this  process  are  somewhat  higher  than  afforded  bv  the  fire  assay. — 
J.  A.  P.  ■  ■ 

Copper,  Nitrate  of,  prepared  by  dissolving  copper  in  moderately  strong  nitric  acid, 
and  evaporating  to  crystallization.  Its  formula  is  CuO,NO^  Tliis  salt  is  used  to  jji-oduce 
a  fine  green  in  fireworks.  ♦ 

Copper,  Si^lpiiate  of,  called  in  commerce  Bute  Vitriol.  Bh'e  Stone.  Bi.imo  Cop- 
peras.— This  salt  is  frequently  prepared  by  roasting  copper  pyrites  with  free  access  of  air. 
It  is  also  obtained  by  heating  old  copper  with  sulphur,  by  which  a  subsulphidc  of  copper  is 

*  The  rpfininf;  flux  consists  of  two  parts  of  nitre  and  one  of  white  tartar  fused  together,  and  subse- 
quently pounded. 


~] 


41G 


COPYING. 


produced ;  this  is  converted  into  sulphate,  by  i-oasting  in  contact  with  air.  Large  quan- 
tities of  sulphate  of  copper  are  obtained  in  the  process  of  silver  refining.  See  Pyrites  and 
Silver. 

COPYING.  A  new  and  important  quality  of  writing-inks  was  introduced  by  the  inde- 
fatigable James  Watt,  in  17S0,  who  in  that  year  took  out  a  patent  for  copying  letters  and 
other  written  documents  by  pressure.  The  modus  operandi  being  to  have  mixed  with  the 
ink  some  saccharine  or  gummy  matter,  which  should  prevent  its  entire  absorption  into  the 
paper,  and  thus  render  the  writing  capable  of  having  a  copy  taken  from  it  when  pressed 
against  a  damp  sheet  of  common  tissue  paper.  But  although  this  process  was  very  imper- 
fect, the  writing  generally  being  much  besmeared  by  the  dumping,  and  the  copies,  in  many 
cases,  only  capable  of  being  read  with  great  difficulty,  it  was  not  for  seventy-seven  years 
after  the  invention  of  Watt  that  any  improvement  in  such  inks  was  attempted.  The  firm 
of  Underwood  and  Burt  patented  a  method  of  taking  copies  by  the  action  of  a  chemically 
prepared  paper,  in  a  chemical  ink,  by  which,  not  only  arc  far  superior  copies  taken,  and 
the  original  not  at  all  damaged,  but  many  copies  may  be  taken  at  one  time  from  a  single 
document.  Printed  matter  may  also  be  copied  at  the  same  time,  on  the  same  beautiful 
principle.     We  give  the  specification  of  Mr.  Underwood  : — 

"But  while  the  means  employed  for  producing  the  desired  effects  may  be  varied,  I  pre- 
fer the  following  for  general  use : — I  damp  the  jiapcr,  i)archment,  or  other  material  which 
I  desire  to  copy  upon,  with  a  solution  of  200  grains  of  the  yellow  or  neutral  chromate  of 
potash  dissolved  in  1  gallon  of  distilled  water,  and  either  use  it  immediately,  or  dry  it  and 
subsequently  damp  it  with  water  as  it  is  required  for  use.  I  then  prepare  the  material 
which  I  use  for  jiroducing  the  characters  or  marks,  and  which  may  be  called  copying  ink, 
by  simply  dissolving  (in  a  water  bath)  pure  extract  of  logwood  in  distilled  water;  or,  for 
printing,!  use  a  varnish  or  other  similar  material  soluble  in  water,  and  dust  or  throw  over 
it  powdered  extract  of  logwood.  If  I  desire  to  take  twenty  copies  from  an  original,  I  use 
about  six  pounds  of  the  pure  extract  of  logwood  to  a  gallon  of  distilled  water ;  but  a  larger 
number  of  copies  may  be  taken  by  dusting  or  throwing  over  the  original,  before  the  ink 
has  thoroughly  dried,  a  powder  composed  of  five  parts  of  powdered  extract  of  logwood, 
one  part  of  powdered  gum  arable,  and  one  part  of  powdered  tragacanth.  When  I  desire  to 
print  from  an  original,  in  producing  which  I  have  used  ink  prepared  as  before  described,  I 
proceed  by  damping  six  sheets  of  paper,  prepared  as  before  described,  and  having  taken 
off  all  superfluous  moisture  with  good  blotting  paper,  I  place  the  original  upon  the  upper 
sheet  and  press  the  whole  for  about  half  a  minute  in  a  copying  press ;  I  then  remove  the 
original,  and  in  its  place  put  six  other  sheets  of  the  prepared  paper  in  a  damp  state,  and 
subject  the  whole  to  pressure  for  about  a  quarter  of  an  hour.  I  then  take  five  other  pre- 
pared sheets  in  a  damp  state,  and  having  laid  the  original  upon  them,  press  them  together 
for  about  two  minutes,  then  replace  the  original  by  three  other  prepared  and  damped  sheets, 
and  press  the  whole  together  for  about  a  quarter  of  an  hour.  The  extract  of  logwood  so 
acts  upon  the  neutral  chromate  of  potash  that  I  thus  obtain  twenty  good  clear  fac-similes 
of  the  original  matter  or  design." 

They  have  also  produced  an  Indian  ink  on  the  same  principle,  which,  when  used  in  the 
preparation  of  architectural  plans,  niaps,  &c.,  will  give  one  or  more  dear  copies  of  even  the 
finest  lines.  The  only  point  to  be  observed  in  the  taking  of  such  copies,  is  that  as  they  are 
done  to  a  scale,  they  must  be  kept  pressed  in  close  contact  with  the  original,  till  they  are 
perfectly  dry,  because  if  not  they  will  shrink  in  drying,  and  the  scale  be  spoilt. 

The  most  complete  information  on  this  subject,  and  that  of  inks  generally,  is  to  be  found 
in  a  memoir  read  before  the  Society  of  Arts,  on  the  15th  December,  by  Mr.  John  Under- 
wood. 

COQUILLA  NUTS.  These  nuts  are  produced  in  the  Brazils  l)y  the  Atfalca  funifera. 
They  are  suitable  for  a  great  variety  of  small  ornamental  works,  and  are  manufactured  into 
the  knobs  of  umbrellas  and  parasols. 

CORDAGE; — {C'ordaffe,  Fv. ;  Tamcerk,  Germ.)  Cordage  may  be,  and  is,  made  of  a 
great  variety  of  materials.  In  Europe,  however,  it  is  mostly  formed  of  hemp,  although 
now,  much  cordage  is  made  of  Coir.     See  Coir. 

Professor  Robinson  proposed  the  following  rule,  for  determining  the  strength  of  cordage. 
Square  the  circumference  of  a  rope  m  inches ;  one-fifth  of  the  product  will  be  the  number 
of  tons'  weight  which  it  will  bear:  this  is,  however,  uncertain. 

COROMANDEL  WOOD.     The  wood  of  the  Dyospyros  hirsuta. 

CORROSIVE  SUBLIMATE,  Mercury,  Chloride  of,  or  FrotocJiloride,  {Ikntochloritrc 
dc  vrcrcure,  Fr. ;  Aetsendrs  rjuecJ^ilber  snblimaf,  Germ.,)  is  made  by  subliming  a  mix- 
ture of  2-^  parts  of  sulphate  of  oxide  of  mercury,  and  one  part  of  sea-salt,  in  a  stoue- 
ware  cucurbit.  The  sublimate  rises  in  vapor,  and  encrusts  the  globular  glass  capital 
with  a  wliite  mass  of  small  prismatic  needles.  Its  specific  gi'avity  is  6-225.  Its  taste 
is  acrid,  stypto-metallic,  and  exceedingly  unpleasant.  It  is  soluble  in  16  parts  of  water, 
at  the  ordinary  temperature,  and  in  less  than  three  times  its  weight.  It  dissolves  in  2:^ 
times  its  weight  of  cold  alcohol.     It  is  a  very  deadly  poison.     Raw  white  of  eggs  swal- 


COTTON  MANUTACTUEE. 


417 


lowed  in  profusion  is  the  best  antidote.  A  solution  of  corrosive  sublimate  has  been 
long  employed  for  preserving  soft  anatomical  preparations.  By  this  means  the  corpse 
of  Colonel  Morland  was  embalmed,  in  order  to  be  brought  from  the  seat  of  war  to  Paris. 
Ilis  features  remained  unaltered,  only  his  skin  was  brown,  and  his  body  was  so  hard  as  to 
sound  like  a  piece  of  wood  when  struck  with  a  hammer. 

In  the  work  upon  the  dry  rot,  published  by  Mr.  Knowles,  secretary  of  the  committee  of 
inspectors  of  the  navy,  in  1821,  corrosive  sublimate  is  enumerated  among  the  chemical 
substances  which  had  been  prescribed  for  pi-eventing  the  dry  rot  in  timber ;  and  it  is  well 
known  that  Sir  H.  Davy  had,  several  years  before  that  date,  used  and  recommended  to  the 
Admiralty  and  Xavy  Board  corrosive  sublimate  as  an  anti-dry-rot  application.  It  has  been 
since  extensively  employed  by  a  joint-stock  company  for  the  same  purpose,  under  the  title 
of  Kyan's  patent. 

The  preservative  liquid  known  as  Goadby's  solution,  which  is  employed  for  preserving 
wood  and  anatomical  preparations,  is  composed  as  follows  : — Bay  salt,  4  oz. ;  alum,  2  oz. ; 
corrosive  sublimate,  2  grains ;  water,  2  pints. 

The  composition  of  corrosive  sublimate  is — 

Mercury         -         -         100"  YS-SS 

Chlorine         -         -  35-5  26-14 


135-5  100-00  H.  M.  K 

See  Mercury. 

CORRUGATED  TROX.  A  process  has  been  introduced  for  giving  strength  to  sheet 
iron,  by  bending  it  into  folds  or  wrinkles ;  the  iron  so  treated  is  thus  named. 

The  iron  shed  at  the  London  Terminus  of  the  Eastern  Counties  Railway,  constructed  of 
corrugated  iron,  has  been  described  by  Mr.  W.  Evill,  jun.  The  entire  length  is  216  feet, 
and  consists  of  three  roofs,  the  centre  of  36  feet  span,  rising  9  feet,  and  the  side-roofs  20 
feet  6  inches,  with  a  rise  of  four  feet. 

The  corrugated  wrought-iron  is  composed  of  sheets  No.  16  wire  gauge,  or  '/i*  of  an 
inch  in  thickness ;  the  weight  per  foot  is  3  lbs. ;  the  whole  weight  of  the  centre  roof  of 
10,235  superficial  feet  bemg  scarcely  13f  tons,  and  the  side  roofs,  of  5,405  square  feet, 
weigh  1\  tons. 

The  whole  roof  was  erected  by  Messrs.  Walker  and  Sons,  Bermondsey,  the  holders  of 
Palmer's  patent,  at  a  charge  of  £6  10s.  per  100  superficial  feet,  including  fixing,  and  the 
whole  roofs  cost  £1,365,  and  might  now  be  erected  for  half  the  cost,  the  patent  having  ex- 
pired, and  increased  facilities  existing. 

Many  corrugated  roofs  have  been  erected :  one  at  St.  Katherine's  Dock.  At  the  en- 
trance of  the  London  Docks  there  is  one  4()  feet  span  and  225  feet  long.  On  the  London, 
Birmingham,  Great  Western,  and  other  railways  they  have  been  employed. 

Iron  appears  to  have  great  strength  given  to  it  by  this  change  of  form  ;  a  single  sheet, 
so  thin  as  to  be  unable  to  bear  its  own  vertical  position,  will  bear  700  lbs.  after  corrugation 
without  bending. 

Cast-iron  has  been  corrugated.  Mr.  Palmer  has  patented  this  form,  and  at  Swansea  a 
bridge  of  three  arches,  one  of  50  and  two  of  48  feet  span,  has  been  erected. 

COTTON  AND  COTTON  MANUFACTURE.  Fig.  198  is  F.  A.  Calvert's  patent, 
toothed  roller  cotton  gin. 

a  is  a  perspective  view,  6  is  a  sectional  view,  a  is  the  box  to  hold  seed  cotton  ready 
to  be  ginned ;  b  is  the  top  of  the  hopper ;  c  is  the  fluted  guard ;  D  is  the  fine-toothed 
roller ;  e  the  brush ;  F  is  the  discharge  pipe ;  and  G  is  a  suitable  block  on  which  the 
machine  stands. 

N.  B. — Over  the  handle  in  fig. «  there  is  shown  an  arrow,  indicating  the  direction  of 
the  motion.  The  handle  should  not  be  driven  less  than  fifty  turns  per  minute.  The  seed 
cotton  should  be  fed  into  the  hopper  in  small  portions,  and  regularly  throughout  its  whole 
length  ;  at  the  same  time  care  should  be  taken  that  a  large  quantity  does  not  collect,  as  it 
will  retard  the  operation.  This  gin  is  made  from  six  inches  to  five  feet  wide  ;  two  persons 
can  drive,  with  ease,  a  gin  of  this  kind  three  feet  wide,  producing  200  lbs.  of  cleaned  cotton 
per  day,  at  the  speed  above  stated.  When  driven  by  steam  or  water  power  at  the  rate  of 
200  revolutions  per  minute,  it  will  clean  400  lbs.  each  foot  in  length  per  day.  It  is  well 
adapted  for  all  classes  of  cotton,  particularly  fast  seed  cotton,  which  has  been  valued  at  one 
penny  per  pound  more  when  done  on  this  gin  than  when  done  on  the  saw  gin.  It  will  be 
seen  that  there  is  no  band  or  bolt  employed,  hence  the  machine  requires  small  power  com- 
'pared  with  other  machines  for  like  purposes. 

After  the  cotton  wool  is  thus  separated  from  the  seeds,  it  is  packed  in  large  canvas 
bags,  commonly  with  the  aid  of  a  screw  or  hydraulic  press,  into  a  very  dense  bale,  for  the 
convenience  of  transport.  Each  of  the  American  bags  contain^"  about  500  lbs.  of  cotton 
wool.  When  this  cotton  is  delivered  to  the  manufacturer,  it  is  so  foul  and  flocky,  that  he 
must  clean  and  disentangle  it  with  the  utmost  care,  before  he  can  subject  it  to  the  carding 
operation. 

Vol.  III.— 27 


418 


COTTON  MANUFACTURE. 

198  ^ 


Fig.  199,  the  scutcher  or  opening  machine,  though  usually  preceded  by  the  willow,  is 
often  the  first  machine  in  a  mill  through  which  the  cotton  is  passed,  and  serves,  as  its 
name  implies,  to  open  the  matted  locks  of  cotton  and  separate  its  fibres,  and  at  the  same 
time  to  remove  a  large  percentage  of  the  seed  and  dirt  which  may  have  been  packed 
with  it. 


190 


The  cotton  is  placed  upon  the  travelling  creeper  marked  «,  which  is  made  of  a  number 
of  narrow  slips,  or  laths,  of  wood,  screwed  to  three  endless  bands  of  leather,  the  pivots  of 
which  are  marked  b  and  c.  Motion  is  given  to  the  roller  e,  by  a  wheel  on  the  end  of  the 
feed  roller,  thus  causing  the  creeper  to  advance,  carrying  with  it  the  cotton  to  the  feeding 
rollers  d ;  these  revolving  slowly  pass  the  cotton  to  the  second  smaller  pair  of  fluted  rollers, 
which  serve  it  to  the  beater. 

The  top  feeding  rollers  are  weighted  bv  levers  and  weights  e  e,  and  hold  the  cotton 
sufficiently  tight  for  the  beater  to  act  upon  it. 

The  beater  is  placed  inside  the  machine  at  /,  and  extends  quite  across 
its  breadth,  its  shaft  or  axis  being  shown  with  the  speed  fully  upon  it  at  ff. 
The  form  of  the  beater  varies,  but  we  give  the  following  as  an  example : — 
On  a  shaft  are  placed  four  or  five  spiders,  each  having  three  or  four  arms ; 
to  tlie  ends  of  these  arms  are  attached  steel  blades,  which  pass  along 
the  whole  length  of  the  beater ;  two  of  the  arms  being  shorter  than  the 
other  arms  of  the  spider,  allow  two  of  the  blades  to  contain  a  double  row 


200 


COTTON  MANUFACTUPvE.  419 

nfji'^nL'^lf  ^^  the  points  Of  the  spikes  being  at  the  same  distance  from  the  axis  as  the 
«n7uo=  IT  -i  ?h^'-  ..  '  '^^,  ^'^^*^',  '^''^''^''^^  ^^°"^  ^'^'O  turns  per  minute,  the  blades  and 
th n«  f  !r>  f  '''"°"  T^  considerable  ibrce  as  it  is  passed  from  the  feeding  rollers,  and 
tnus  tree  it  irom  many  of  its  impurities. 

hn rJ'^.rt?^^  '''"^"'''  ^^''•^^'f  '''"";'  f"^  ^"^'^'•'  ^'•^  P'^^'^^  a  "»°^ber  of  wedge-shaped 
IpH;S  f  r''/  ^e"]'-"'-^"'^'-  8"^,  through  the  narrow  openings  of  which  the°dirt  and 
seeds  fall  to  the  floor,  their  removal  being  effected  through  the  doors  in  the  framintr  To 
prevent  the  cotton  passing  with  the  dirt  through  the  grid,  a  current  of  air  to  draw  the  cot- 
ton from  the  beater  to  the  cage,  is  produced  by  an  exhaust  fan  (its  axis  being  shown  at  h) 
receiving  its  motion  from  a  pulley  on  the  beater  shaft.  The  projection  i  on  the  framinc^ 
orms  a  pipe,  through  which  the  fan  draws  the  air  from  the  beater,  passing  on  its  way 
through  a  large  revolving  cage  or  cylinder,  the  periphery  of  which  is  formed  of  sheets  of 
perforated  metal,  or  wire  gauze.     Its  axis  is  shown  at  k. 

From  the  cage  the  cotton  is  delivered  by  a  second  travelling  creeper  and  falls  into  a 
machine    '  '*  ''  ""'"'^  "'''^  °'''^'  ''^'^^  ^""^   '^'^  operations   of  the   lap 

tho=f  f  ■  "^/'  ^^^'  represent  skeletons  of  the  old  cards,  to  facihtate  the  comprehension  of 
hese  complex  macnnes.  F,rf.  201  is  a  plan  ;  f  is  the  main  cylinder  ;  m  m  is  the  doffer 
knife  or  comb  ;  G,  the  carded  fleece  hemmed  in  by  the  funnel  a,  pressed  between  the  rollers 


201 


202 


"^r^ 


b,  and  then  falling  in  narrow  fillets  into  its  can.  Fiff.  202,  k  l  are  the  feed  rollers  •  a  b  the 
main  cylinder ;  c  d,  the  tops ;  e  f,  the  doffer  card ;  m  n,  the  doffer  knife :  d,  L  c,  the  card- 
end  passing  between  compressing  rollers  into  the  can  a. 


203 


420 


COTTOJq^  MANUFACTURE. 


per  week  of  60  hours!  ™'^''  ^'^'^'"''  "^'^  ^^''^  ^^^^d  f«r  COO  lbs.  of  twenties 

upoiU^TeS  clplt'entnT  ""  '°°^'  ''^"^'^^'^'■'  ^"*'-^^'  ^^  --'  -^^  -ay  be  looked 

204 


duced 'i'lZn/'r'  '°^""ff  *^t»r^d  »,y  Messrs.  Hetherington  &  Sons,  Manchester,  having  pro- 
hivention  nTi  ♦''  ''f''^'"  '.*'"  in  the  preparation  of  fine  yarns,  we  give  a  brief  history  of  its 
invention  prior  to  describmg  it  in  detail. 

About  the  year  1844,  Mr.  Jean  Jacques  Bourcart,  one  of  the  partners  of  the  eminent 


COTTON  MANUFACTURE.  421 

firm  of  Messrs.  Nicolas  Schlumberger  &  Co.,  of  Guebwiller,  in  the  department  du  Haut 
Rliin  in  the  kingdom  of  France,  offered  a  prize  of  a  considerable  sum  of  money  to  any  per- 
son who  should  invent  a  machine  that  would  supersede  the  carding  engine  in  the  treatment 
of  the  fibres  of  cotton,  suitable  for  fine  numbers,  such  machine  to  be  free  from  the  objec- 
tions urged  against  the  carding  engine  of  breaking  the  fibres  of  the  cotton,  and  delivering 
them  in  the  staple  or  hook  form  ;  and  besides  this,  it  was  to  possess  the  peculiar  property 
of  separating  the  long  fibres  from  the  short  ones ;  and  after  laying  the  long  fibres  parallel 
to  each  other,  pass  them  out  of  the  machine  in  a  perfectly  cleaned  state  in  the  form  of  a 
sliver  ready  for  the  drawing  frame. 

In  a  short  time  after  this  announcement  Mr.  Bourcart  was  waited  upon  by  Mr.  Josae 
Heilmanrf,  of  Mulhausen,  in  the  department  du  Haut  Rhin  in  the  kingdom  of  France,  ma- 
chine maker,  who  informed  him  that  he  claimed  the  prize.  Mr.  Heilmann,  feeling  satisfied 
that  his  invention  was  a  valuable  one,  made  application  for  a  patent  in  England,  which 
patent  was  sealed  on  the  25th  of  February,  1846. 

The  specification  of  Mr.  Heilmann's  invention  is  very  clear  and  concise,  and  a  single 
extract  from  it  will  be  sufficient  to  convey  to  the  mind  of  the  practical  spinner  the  nature 
and  object  of  his  invention.  He  says  : — "  My  invention  consists,  secondly,  in  a  new  com- 
bination of  machinery  for  the  purpose  of  combing  cotton,  as  well  as  wool  and  other  fibrous 
materials,  into  which  machine  the  fibres  as  they  come  from  the  dressing-machine  are  intro- 
duced in  a  lap  sliver  or  fleece,  which  is  broken  asunder,  and  the  fibres  are  combed  at  each 
end,  and  the  long  and  short  fibres  are  separated,  the  long  ones  being  united  in  one  sliver, 
the  short  ones  in  another,  and  they  are  passed  out  of  the  machine  thus  separated  ready  for 
drawing,  roving,  and  other  subsequent  operations." 

Mr.  Heilmann  did  not  live  long  enough  to  reap  the  reward  of  his  genius  for  inventing 
this  and  other  important  machines,  and  his  son,  Jean  Jacques  Heilmann,  was  under  the 
necessity  of  bringing  an  action  for  the  infringement  of  the  combing  machine  patent  against 
certain  parties  in  Yorkshire ;  the  trial  took  place  before  the  Lord  Chief  Justice  of  the 
Queen's  Bench  and  a  special  jury  at  the  Guildhall,  London,  on  the  27th  and  2Sth  of  Febru- 
ary, 1852,  which  resulted  in  a  verdict  for  the  plaintiff,  thereby  establishing  the  validity  of 
the  patent.  Since  that  period  a  considerable  number  of  machines  have  been  set  to  work  in 
this  country ;  and  although  several  patents  have  been  taken  out  for  certain  improvements 
introduced  into  these  machines,  still  the  combination  of  a  delivering,  combing,  and  drawing 
apparatus,  and  their  mode  of  action,  is  retained,  as  will  be  seen  in  the  following  description 
of  Cross  Section  of  Combing  Machine,  fig.  204. 

1  is  the  lap  of  cotton  resting  upon  the  two  wooden  rollers  2,  2a.  When  motion  is 
given  to  these  rollers,  they  cause  the  lap  to  unwind  and  deliver  the  sheet  of  cotton  down 
the  inclined  conductor  3,  and  between  the  fluted  steel  feeding  roller  4,  and  the  leather-cov- 
ered pressure  roller  4a  ;  to  these  rollers  an  intermittent  motion  is  given  by  means  of  a  star 
wheel ;  they  make  '/lo  of  a  revolution  to  one  revolution  of  the  cylinder  6,  this  motion  being 
effected  during  the  time  the  cushion  plate  oa  is  forward,  and  the  nipping  plate  5  is  lifted 
from  it.  The  cushion  plate  5rt  is  hung  upon  the  centre  56,  and  the  nipping  plate  upon  the 
shaft  5c,  and  this  shaft  receives  motion  from  a  cam  at  the  end  of  the  machine  through  the 
lever  5«,  the  connecting  rod  13'/,  lever  13'-,  and  shaft  136, — the  parts  being  so  arranged  that 
the  cushion  plate  5a  is  pressed  backward  by  the  nipping  plate  5,  but  as  soon  as  the  pressure 
is  removed  it  is  drawn  forward  by  a  spring  until  it  ai-rives  at  the  strap.  Besides  this  move- 
ment, the  nipping  plate  is  caused  to  move  on  its  own  axis,  which  enables  it  to  quit  contact 
with  the  cushion,  while  the  cotton  is  being  fed  in  between  them. 

In  the  engraving  {fig.  204)  the  cushion  5a  is  represented  as  thrown  back  by  the  nipping 
plate  5,  and  while  in  this  position  the  cotton  is  held  between  them,  until  tlie  combs  on  the 
cylinder  pass  between  the  fibres  of  cotton  which  protrude,  and  remove  from  them  all  im- 
purities and  the  fibres  which  are  too  short  to  bo  held  by  the  nipper.  The  combing  cylinder 
Ca  is  attached  to  the  shaft,  or  axis  6,  by  which  it  is  caused  to  revolve.  The  periphery  of 
this  cylinder  is  divided  into  four  unequal  parts  by  the  combs  66  on  one  side,  and  the  fluted 
segment  6c  on  the  other  side  ;  the  spaces  between  them  being  plain  to  allow  time  for  the 
nipper  and  leather  detaching  roller  8a  to  change  their  positions. 

The  combs  on  the  cylinder  are  made  with  teeth  at  various  distances,  the  coai-ser  ones 
taking  the  lead,  and  finer  teeth  following,  the  last  combs  having  more  than  80  teeth  in  a 
lineal  inch.  All  impurity  or  waste  mixed  with  the  fibres  held  by  the  nipper  is  carried  away 
by  these  combs,  which  at  every  revolution  are  cleaned  by  the  cylindrical  brush  lOa,  strip- 
ping the  waste  from  them,  and  depositing  it  upon  the  travelling  creeper  11a,  formed  of 
wired  cloth,  wliich  carries  it  down  until  the  doffing  knife,  or  steel  blade  12,  removes  it  in 
the  usual  manner ;  it  then  drops  into  a  waste  box,  and  is  afterwards  worked  into  coarser 
yarns.  A  cylindi'r  covered  with  wired  cloth  "is  sometimes  used  instead  of  the  travelling 
creeper,  and  acts  in  a  similar  way. 

As  soon  as  the  combs  have  all  passed  the  fibres  held  by  the  nipper,  the  cushion  plate  5a 
is  drawn  forward,  and  the  nipper  plate  5  is  lifted  from  it,  and  thus  releases  the  fleece  ;  the 
fluted  segment  Oc  on  the  cylinder  is  at  the  same  time  passing  immediately  under  the  cushion 


422  COTTON  MANUFACTURE. 

plate  5a,  the  ends  of  the  combed  fibres  lying  upon  it,  and  as  the  leather  detaching  roller  8a 
has  been  lowered  into  contact  with  the  fluted  segment,  they  are  then  drawn  forward  ;  but 
as  it  is  necessary  to  prevent  any  fibres  passing  that  have  not  been  properly  cleaned  or 
combed,  the  top  comb  7  is  placed  between  the  nipper  and  the  roller,  and  as  this  comb  falls 
and  penetrates  the  fleece  just  in  front  of  the  part  uncombed  by  the  cylindrical  combs,  it 
prevents  any  waste  from  being  drawn  forward  with  the  tail  end  of  the  clean  fibres. 

The  leather  detaching  roller  8a,  in  addition  to  its  occasional  contact  with  the  fluted  seg- 
ment 6f,  is  always  in  contact  with  the  fluted  steel  detaching  roller  8,  and  participates  in  its 
movements. 

These  rollers  are  stationary  while  the  cylinder  combs  are  cleaning  the  fibres  projecting 
from  the  nipper,  but  as  soon  as  that  operation  is  completed,  they  are  put  into  motion,  and 
make  part  of  a  revolution  backward,  taking  back  with  them  the  fibres  previously  combed, 
but  taken  out  of  the  way  to  allow  the  cylinder  combs  to  pass,  in  order  for  the  next  fibres 
coming  forward  to  be  joined  or  pieced  to  them,  so  as  to  form  a  continuous  sliver  or  ribbon. 
As  soon  as  the  backward  movement  is  completed,  the  leather  detaching  roller  8a  is  made  to 
approach  the  cylinder  by  the  lever  S/,  which  receives  motion  from  a  cam  at  the  end  of  the 
machine,  through  the  lever  Sd,  connecting  rod  8c,  lever  14c,  and  shaft  lib.  Before,  how- 
ever, it  comes  in  contact  with  the  fluted  segment  6c,  the  movement  of  the  fluted  roller  is 
reversed,  and  it  is  caused  to  turn  forward,  producing  a  corresponding  movement  of  the  de- 
taching roller  So.,  the  speed  being  so  arranged  that,  before  they  are  allowed  to  touch  each 
other,  the  peripheries  of  the  fluted  segment  Gc  and  the  roller  8a  travel  with  an  equal  veloc- 
ity. At  this  stage,  the  ends  of  the  fibres  cleaned  by  the  cylinder  combs  and  projecting  from 
the  nipper,  are  resting  upon  the  fluted  segment ;  and  the  roller  8a,  in  coming  in  contact 
with  it,  presses  upon  those  fibres,  and  immediately  draws  them  forward  ;  the  front  ends  are 
then  lifted  by  the  leather  roller  and  placed  on  the  top  of  those  fibres  previously  cleaned, 
and  brought  back  to  receive  them.  The  pressure  of  the  rollers  8  and  Sa  completes  the 
piecing  of  the  fibres ;  the  motion  of  the  rollers  being  continued  until  the  tail  end  of  the 
fibres  is  drawn  through  the  top  comb,  and  a  length  of  fibres  is  delivered  to  the  calender 
rollers, — sufficient  slack  being  left  between  to  allow  for  the  next  backward  movement.  The 
roller  8a  is  then  raised  from  the  fluted  segment  and  ceases  to  revolve. 

From  the  calender  rollers,  the  combed  cotton  passes  along  the  front  plate  or  conductor, 
where  it  joins  the  slivers  from  the  other  five  heads  of  the  machine,  and  with  them  passes 
through  the  drawing  head,  and  is  then  deposited  in  a  can  ready  to  be  removed  to  the  draw- 
ing frame. 

The  movements  above  described  being  necessary  for  each  beat  of  the  combing  machine, 
they  must  all  recur  each  second  of  time,  or  sixty  times  each  minute. 

Recapitulation. — The  combing  machine  is  fed  or  supplied  from  6  laps  of  cotton,  (each 
lap  being  formed  from  about  18  slivers  from  the  breaker  carding  engines,  and  doubled  into 
a  lap  in  the  lap  machine.)  Each  lap  is  8  inches  wide  and  about  12  inches  diameter  when 
full. 

The  following  description  of  the  manner  in  which  the  combing  machine  works  is  con- 
fined to  one  head  supiDlied  by  1  lap,  as  each  of  the  6  heads  shown  in  Jig.  204  is  exactly  like 
the  others : 

The  lap  of  cotton  having  been  placed  on  a  pair  of  revolving  lap  rollers,  the  fleece,  or 
sheet  of  cotton,  is  conducted  down  an  inclined  guide  to  a  fluted  steel  feeding  roller,  which 
places  the  cotton  between  the  open  jaws  of  an  iron  nipper.  The  nipper  is  then  closed  and 
made  to  approach  the  comb  cylinder,  by  means  of  a  cam,  where  it  holds  the  fibres  in  such 
a  position  that  the  combs  of  the  revolving  cylinder  pass  between  and  remove  from  the  fibres 
all  impurities  and  short  or  broken  cotton,  which  are  afterwards  worked  up  into  yarns  of  a 
coarser  quality. 

As  soon  as  the  combs  have  all  passed  through  the  cotton,  the  nipper  recedes  from  the 
cylinder,  and  as  soon  as  it  has  reached  the  proper  distance,  opens  its  jaws,  and  allows  the 
partially  combed  filires  to  be  drawn  out  of  the  fleece,  by  means  of  a  leather-covered  roller, 
which  works  for  this  purpose  in  contact  with  the  fluted  segment  on  the  comb  cylinder,  and 
with  the  fluted  steel  detaching  roller.  The  drawing  out  of  these  fibres  causes  the  ends  of 
those  fibres  which  were  before  held  in  the  nipper  to  pass  between  the  teeth  of  a  fine  top 
comb,  thus  completing  the  combing  of  each  separate  fibre.  Previous  to  the  movement  for 
drawing  out  the  fibres  from  the  uncombed  fleece,  the  detaching  roller  has  made  a  partial 
revolution  backwards,  and  taken  with  it  the  combed  cotton  previously  delivered,  in  order  to 
piece  it  to  the  fil)res  just  combed. 

The  machine  is  so  arranged  that  the  forward  movement  of  the  detaching  roller  overlaps 
the  ends,  and  brings  out  the  cotton  in  a  continuous  sliver  to  the  front  of  the  machine,  where 
it  joins  the  other  five  slivers  which  have  been  simultaneously  produced  on  the  other  heads 
of  the  machine.  The  united  slivers  then  pass  through  the  drawing  head  to  the  next  opera- 
tion— the  drawing  frame.     (See  Vol.  1.) 

Fig.  204a  is  a  drawing  frame,  by  Hetherington  &  Sons,  containing  all  the  latest  im- 
provements, i.  e.,  greater  strength  of  materials ;  a  stop  motion  to  stop  the  frame,  when 


COTTON  MANUFACTUEE. 


423 


a  sliver  breaks  ;  a  roller  plate  to  prevent  roller  laps.    The  coiler  motion,  by  ineuu: 
the  sliver  is  placed  in  the  can  in  circles  overlapping  each  other  on  the  principle 


;  of  which 
described 


204  a 


in  fifj.  2046,  the  can  roving  frame ;  4  rows  of  draught  rollers  instead  of  3  ;  and  lastly,  an 
apparatus  for  lifting  all  the  roller  weights  from  off  the  rollers  at  any  time  when  the  frame 
may  be  stopped. 

The  stul)bing  frame  {ficj.  2046)  is  the  first  machine  which  puts  twist  into  the  silver,  and 
prepares  it  for  the  roving  frame,  which  in  its  principle  it  precisely  resembles. 


2046 


The  preliminary  spinning  process  is  called  rovinrt.  At  first  the  torsion  is  slight  in  pro- 
portion to  the  extension,  since  the  solidity  of  the  still  coarse  sliver  needs  that  cohesive  aid 
only  in  a  small  degree,  and  looseness  of  texture  must  be  maintained  to  facilitate  to  the 
utmost  the  further  elongation. 

Fig.  205  shows  the  latest  construction  of  a  bobbin  and  fly  frame,  as  made  by  Messrs. 
Higgins  &  Sons,  of  Manchester.  As  the  principle  of  action  is  similar  to  that  already  de- 
scribed, it  only  needs  to  add  that  many  improvements  have  been  introduced  by  the  makers, 
as  will  be  seen  on  reference  to  the  engraving.  1  represents  a  front  view  of  the  frame;  2  a 
view  of  the  back  of  the  frame ;  3  shows  the  driving  pulley  and  gearing  end  ;  and  4  the 
same  end  with  the  iron  casing  removed,  so  as  to  exhibit  the  works  inside. 

The  spindles  and  bobbins  being  now  driven  by  gearing  instead  of  by  bands  as  formerly, 

-  and  greater  strength  of  materials  being  introduced  throughout  tiie  frame,  it  is  capable  of 

producing  a  better  quality  with  an  increased  quantity  of  rovings  than  was  possible  formerly. 

Fic).  20G  also  represents  a  similar  frame  for  rovings,  made  by  Iletherington  &  Sons. 
Its  action  is  the  same  as  that  already  described. 

Fig.  207  is  a  view  of  one  of  the  most  improved  forms  of  the  throstle  frame  by  Messrs. 
Iletherington  &  Sons,  Manchester. 


424 


COTTON  MANUFACTURE. 

205 


COTTON  MANUFACTUEE. 
206 


425 


The  Self- Ac  tin  rf  Midc. — In  a  previous  edition  of  this  work,  mention  was  made  of  the 
patent  self-acting  mules  of  Mr.  Roberts,  of  Manchester,  and  of  Mr.  Smith,  of  Deanstone. 
Since  the  period  when  that  notice  was  written  a  great  number  of  patents  have  been  olj- 
tained  for  improvements  on  the  original  patents,  by  Mr.  Potter,  of  Manchester,  Messrs.  Big- 
gins &  Whitworth,  of  Salford,  Mr.  Montgomery,  of  Johnstone,  Messrs.  Craig  &  Sharp,  of 
Glasgow,  and  many  others.  ^ 

Mr.  Roberts's  self-acting  mule,  which  was  practically  the  first  introduced,  has  maintained 
its  ground  against  all  competitors,  and  is  still  the  mule  which  is  most  extensively  used  and 
approved  in  the  cotton  trade. 

As  might  be  expected,  it  has  undergone  a  variety  of  improvements  and  alterations  by 
the  various  machine  workers  who  have  made  it  since  the  expiration  of  the  patent,  but  Iiy 
none  more  than  by  Messrs.  Parr,  Curtis  &  Madely,  of  Manchester,  who  have  devoted  a  large 
amount  of  time  and  expense  in  its  perfection. 

They  are  the  proprietors  of  six  patents  for  this  mule,  the  invention  of  Mr.  Curtis,  of  the 
manager  Mr.  Lakin,  and  of  Messrs.  Rhodes  &  Wain,  the  combination  of  which  has  enabled 
that  firm  to  produce  a  very  superior  self-acting  mule,  and  given  them  a  decided  lead  as 
makers. 

The  following  are  some  of  the  principal  improvements  they  have  effected:  viz.,  substi- 
tuting a  catch-box  with  an  eccentric  box,  in  lieu  of  a  cam  shaft,  to  produce  the  required 
changes ;  an  improved  arrangement  of  the  faller  motion,  which  causes  the  fallcrs  to  act 
more  easily  upon  the  yarn,  and  not  producing  a  recoil  in  them  when  the  "  backing-off " 
takes  place,  thus  preventing  "  snarls  "  and  injury  to  the  yarn  ;  in  applying  a  spiral  spring 
for  the  purpose  of  bringing  the  backing-off  cones  into  contact,  by  which  the  operation  of 
"  backing-off"  can  be  performed  with  the  greatest  precision.  The  backing-off  movement  is 
also  made  to  stop  itself,  and  to  cauS'e  the  change  to  be  made  which  affects  the  putting-up 
of  the  carriage,  which  it  does  in  less  time  than  if  an  independent  motion  was  employed. 
They  have  also  an  arrangement  for  driving  the  back,  or  drawing-out  shaft,  by  gearing,  in 
such  a  manner  that,  in  the  event  of  an  obstruction  coming  in  the  way  of  the  carriage  going 
out,  the  motion  ceases  and  prevents  the  mule  being  injured. 

By  means  of  a  friction  motion,  the  obj'cct  of  which  is  to  take  the  carriage  in  to  the  roll- 
ers, the  carriage  will  at  once  stop  in  the  event  of  any  obstruction  presenting  itself.  For  the 
want  of  an  arrangement  of  this  nature,  lives  have  been  lost  and  limbs  injured,  when  care- 
less boys  have  been  cleaning  the  carriage  whilst  in  motion,  and  have  been  caught  between 
it  and  the  roller  beam,  and  thus  killed  or  injured. 

Another  improvement  consists  in  connecting  the  drawing-out  shaft  and  the  quadrant 
pinion  shaft  by  gearing,  instead  of  by  bands,  thercljy  producing  a  more  ]ierfcct  winding-on, 
as  the  quadrant  is  moved  the  same  distance  at  each  stretch  of  the  carriage.  They  have  also 
made  a  different  arrangement  of  the  headstock — or  self-acting  portion  of  the  mule — caus- 
ing its  height  to  be  much  reduced,  which  makes  it  more  steady,  oIKm-s  less  obstruction  to 
t'.ie  light,  enables  the  spiimer  to  see  all  the  spindles  from  any  part  of  the  mule,  and  allows 
a -larger  driving  strap,  or  l)elt,  to  be  used,  which  in  low  rooms  is  of  considerable  importance. 
Tlie  result  of  these  various  improvements  is  the  production  of  one  of  the  most  perfoct  spin- 
ning machines  now  in  the  trade. 

For  spinning  very  coarse  numbers,  say  G\s,  they  have  patented  an  arrangement,  by  which 
the  rotation  of  the  spindles  can  be  stopped,  and  the  operation  of  baekiug-off  performed, 
during  the  going  out  of  the  carriage,  thus  effecting  a  considerable  saving  of  time. 


426 


COTTON  MANUFACTUEE. 


Some  of  their  mules  are  working  in  the  mills  of  Messrs.  Thomas  Mason  &  Son,  Ashton- 
under-Lvne,  and  are  making  five  to  five-and-a-half  draws  per  minute,  the  length  of  the 
stretch  being  67  inches — a  speed  and  length  of  stretch  never  previously  attained. 
The  following  is  a  description  of  one  of  those  excellent  mules : — 
Fig.  208  is  a  plan  view,  f(j.  209  a  transverse  section,  and  fg.  210  an  end  view  of  so 
much  of  a  mule  as  is  requisite  for  its  illustration  here. 


208 


As  there  are  many  parts  which  are  common  to  all  mules,  most  of  which  have  been  pre- 
viously dcsci-ibed  in  the  notice  of  the  hand  mule,  we  shall  therefore  only  notice  the  more 
prominent  portions  of  the  self-acting  part  of  the  mule.  Among  such  parts  arc  :  the  framing 
of  the  headstock  a  ;  the  carriage  n  ;  the  rovings  c  ;  the  supports  d  of  the  roller  beam  e  ; 
the  fluted  rollers  a  ;  the  top  rollers  a' ;  the  spindles  b  ;  the  carriage  wheels  6' ;  the  slips,  or 
rails,  6',  on  which  tEey  move ;  the  faller  wire  6' ;  the  counter-faller  wire  b*.     The  following 


COTTON  MANUFACTURE. 


427 


are  the  parts  chiefly  connected  with  the  self-acting  portion  of  the  mule  : — The  fast  pulley  f, 
the  loose  pulley  f',  the  bevels  f*  and  f',  which  give  motion  to  the  fluted  rollers ;  the  back, 
or  drawing-out  shaft  g,  wheels  g'  and  g",  by  which, -through  the  shaft  g^  and  wheels  G'*  and 
G^,  motion  is  communicated  to  the  pinion  g°  on  the  shaft  g",  and  thence  to  the  quadrant  g'. 
The  scroll  shaft  h,  the  scrolls  h"  and  a'-,  the  catch-box  n'',  for  giving  motion  through  the  bevel 
wheels  ii^  and  u*  to  the  scroll  shaft.  Drawing-in  cord  II^  Screw  in  radial  arm  i,  nut  on 
same  i",  winding-on  chain  r,  winding-oa  band  i^,  drawing-out  cord  i\  Pinion  i^  on  front 
roller  shaft,  to  give  motion  through  the  wheels  i^,  i',  and  i",  to  drawing-out  shaft  g.  Pinion  j, 
and  wheels  j*,  J^,  and  J^  for  giving  motion  to  shaft  j* ;  pinion  J^  giving  motion  to  backing- 
off  wheel  A     On  the  change  shaft  k  is  keyed  a  pinion  which  gears  with  the  wheel  j',  and 

209 


receives  motion  therefrom.  One-half  of  the  catch-box  k'  is  fast  to  one  end  of  a  long  hol- 
low shaft  on  which  are  two  cams,  one  of  which  is  used  to  put  the  front  drawing  roller  catch- 
box  M  into  and  out  of  contact ;  the  other  is  used  for  the  purpose  of  traversing  the  driving 
strap  on  or  off  the  fast  pulley  p  as  required.  The  other  half  of  the  catch-box  k'  is  placed 
on  the  shaft  k,  a  key  fast  on  which  passes  through  the  boss  of  the  catch-box,  and  causes  it 
to  be  carried  round  by  the  shaft  as  it  rotates.  Though  carried  round  with  the  shaft,  it  is  at 
liberty  to  move  lengthwise,  so  as  to  allow  it  to  be  put  into  and  out  of  contact  with  the  other 
half  when  required.     The  spiral  spring  k''  is  also  placed  on  the  shaft  k,  and  continually 

210 


bears  against  the  end  of  the  catch-liox  next  to  it,  and  endeavors  to  put  it  in  contact  with 
the  other,  which  it  does  when  permitted  and  the  changes  arc  required.  Tlie  cliangc  lever 
k'-'  moves  on  a  stud  which  passes  through  its  boss  a"  ;  near  which  end  of  this  lever  are  tlie 
adjustable  pieces  a'.  When  the  machine  is  put  in  motion,  sujjposing  the  carriage  to  be 
coming  out,  the  driving  strap  is  for  the  most  part  on  the  fast  pulley  f  when  motion  is  gi^-en 
tlirough  the  bevel  wheels  f'-  and  y'  to  the  drawing  rollers  a,  which  will  then  draw  the  rov- 
ings  c  off  the  bobbins,  and  deliver  the  slivers  so  drawn  at  the  front  of  the  rollers;  and  the 
same  being  fast  to  the  spindles,  as  the  carriage  is  drawn  out  the  slivers  are  taken  out  also, 
and  as  the  spindles  at  this  time  are  turned  round  at  a  ([iiick  rate,  (say  (^(HM)  revolutions  per 
minute,)  they  give  twist  to  the  slivers  and  convert  them  into  yarn  or  twisted  threads.  Mo- 
tion is  communicated  to  the  spindles  from  the  rim  pulley  y\  through  the  rim  band  f',  which 


428  COTTON  MANHFACTUEE. 

passes  from  the  rim  pulley  to  a  grooved  pulley  on  the  tin  roller  shaft,  round  which  it  passes, 
and  thence  round  the  grooved  pulley  f'^  back  to  the  rim  pulley,  thus  forming  an  endless 
band.  It  will  be  seen  that  the  rim  band  pulley  and  the  other  pulleys,  over  or  round  which 
the  rim  band  passes,  are  formed  with  double  grooves,  and  the  band  being  passed  round 
each,  it  forms  a  double  band,  which  is  found  of  great  advantage,  as  it  will  work  with  a 
slacker  band  than  if  only  one  groove  was  used ;  there  is  consequently  less  strain  on  the 
band,  and  it  is  longer.  A  string  or  cord  passes  round  the  tin  roller  to  a  wharve  on  each 
spindle,  round  which  it  passes,  and  thence  back  to  the  tin  roller,  and  thus,  when  the  tin 
roller  receives  motion  from  the  rim  band,  it  gives  motion  to  the  spindles.  The  carriage  is 
caused  to  move  outwards  by  means  of  the  cord  l,  one  end  of  which  is  attached  to  a  ratchet 
pulley  fixed  on  the  carriage  cross,  or  square  l\  and  is  then  passed  over  the  spiral  grooved 
pulley  L"  fast  on  the  drawing-out  shaft  g,  and  passes  thence  under  the  guide  pulley  l^  round 
the  pulley  l*  to  another  ratchet  pulley,  also  on  the  carriage  square,  where  the  other  end  is 
then  fastened.  The  cord  receives  motion  from  the  pulley  l",  round  which  it  passes  and 
communicates  the  motion  it  receives  to  the  carriage,  the  carriage  wheels  6'  moving  freely 
on  the  slips  I?. 

When  the  carriage  has  completed  its  outward  run,  the  bowl  a"  on  the  counter  faller 
shaft  comes  against  the  piece  «',  depresses  it  and  the  end  of  the  lever  k^  to  which  it  is  at- 
tached, and  raises  the  other  end,  and  with  it  the  slide  e,  on  which  are  two  inclines.  A  round 
pin  (not  seen)  passes  through  the  boss  of  the  catch-box  next  to  the  slide,  and  bears  against 
the  sliding  half  of  the  catch-box,  and  holds  it  out  of  contact. 

When  the  slide  c  is  raised,  the  part  of  the  incline  which  bore  against  the  pin  and  kept 
the  catch-box  from  being  in  contact,  is  witlidrawn,  on  which  the  spring  puts  them  in  con- 
tact, and  motion  is  given  to  the  hollow  shaft,  and  the  cams  thereon  ;  one  of  which  causes 
the  catch-box  m  to  be  taken  out  of  contact  when  motion  ceases  to  be  given  to  the  drawing 
rollers  and  to  the  going  out  of  the  carriage  ;  and  the  other  causes  the  driving  strap  to  be 
traversed  off  from  the  fast  pulley  on  to  the  loose  one  when  motion  ceases  to  be  given  to 
the  rim  pulley,  and  thence  to  the  spindles.  The  inclines  on  the  slide  arc  so  formed  that, 
by  the  time  the  shaft  has  made  half  a  revolution,  they  act  on  the  pin  and  cause  it  to  put  the 
catch-box  out  of  contact.  The  next  operation  is  the  backing-off  or  uncoiling  the  threads 
coiled  on  the  spindle  above  the  cop,  which  is  effected  by  causing  the  backing-off  cones 
attached  to  the  wheel  J*^  to  be  put  into  contact  with  one  formed  in  the  interior  of  the  fast 
pulley  F,  when  a  reverse  motion  will  be  given  to  the  rim  pulley  and  thence  to  the  tin  roller 
and  the  spindles. 

The  backing-off  cones  arc  put  into  contact  by  means  of  a  spiral  spring,  which,  when  the 
strap  fork  is  moved  to  traverse  the  strap  on  to  the  loose  pulley,  it  is  allowed  to  do.  Simul- 
taneously with  the  backing-off,  the  putting  down  of  the  faller  wire  takes  place,  which  is 
effected  through  the  reverse  motion  of  the  tin  roller  shaft,  which  causes  the  catch  c'  to  take 
into  a  tooth  of  the  ratchet  wheel  c",  when  they  will  move  together,  and  with  them  the  plate 
c^,  to  a  stud  in  which  one  end  of  the  chain  c*  is  fastened,  the  other  end  of  which  is  attached 
to  the  outer  end  of  the  finger  c*,  fast  on  the  faller  shaft.  When  this  chain  is  drawn  for- 
war.l  by  the  plate,  it  draws  down  the  end  of  the  finger  c*  to  which  it  is  attached,  and  there- 
by partially  turns  the  faller  shaft  and  depresses  the  faller  wire  i^,  and,  at  the  same  time, 
raises  the  lever  t",  the  lower  part  of  wliich  bears  againt-t  a  bowl  attached  to  a  lever  which 
rests  on  the  builder  rail  <•".  As  soon  as  the  lever  c^  is  raised  sufficiently  high  to  allow  the 
lower  end  to  pass  over,  instead  of  bearing  against  the  bowl,  it  is  drawn  forward  by  a  spiral 
spring,  which  causes  the  backing-off  cones  to  be  taken  out  of  contact,  when  the  backing-off 
ceases,  and  the  operations  of  running  the  carriage  in  and  winding  the  yarn  on  to  the  spin- 
dles must  take  place.  When  the  cones  are  taken  out  of  contact,  the  lower  end  of  the  lever 
N  is  withdrawn  from  being  over  the  top  of  the  lever  n\  leaving  that  lever  at  liberty  to  turn, 
and  the  catch-box  n*  thereupon  drops  into  gear,  and  motion  is  communicated  to  the 
scrolls  ii'  and  ir,  and  to  tlio  cords  n^  and  n"".  The  cord  n^  is  at  one  end  attached  to  the 
scroll  n',  and  passes  thence  round  the  pulley  n^  to  the  ratcliet  pulley  ii'  fixed  to  the  back 
of  the  carriage  square.  The  cord  ii'  is  at  one  end  attached  to  the  scroll  ii^,  and  passes 
thence  round  the  pulley  h"*  to  the  ratchet  pulley  n"  fixed  to  the  front  of  the  carriage 
square.  It  will  thus  be  seen  that  the  carriage  is  held  in  one  direction  by  one  band,  and  in 
another  by  the  other  band,  and  that  it  can  only  be  moved  in  either  direction  by  the  one 
scroll  giving  off  as  much  cord  as  the  other  winds  on.  When  the  catch-box  ii"  drops  in 
gear,  the  scroll  n'  winds  the  cord  n^  on,  and  draws  the  carriage  in.  It  will  thus  be  seen 
tlint  the  carriage  is  drawn  out  by  means  of  the  back  or  drawing-out  shaft  o,  and  is  drawn 
in  by  the  scroll  h\  The  winding  on  of  the  thread  in  the  form  of  a  cop  is  effected  by  means 
of  Mr.  Roberts's  ingenious  application  of  the  quadrant  or  radial  arm  g',  screw  i,  and  wind- 
ing-on  chain  i^  and  band  i^  The  chain  i'^  is  at  one  end  attached  to  the  nut  i'  and  at  the 
other  to  the  band  i^  During  the  coming  out  of  the  carriage,  the  drawing-out  shaft,  through 
the  means  of  the  wheels  G*,  g',  g*  and  g**,  .shafts  g'  and  g",  and  pinion  g**,  moves  the  quad- 
rant which,  by  the  time  the  carriage  is  quite  out,  will  have  been  moved  outwards  a  little 
past  the  perpendicular.    The  chain  is  wound  on  to  the  barrel  by  means  of  the  cord  o,  which, 


COTTOIT  MANUFACTURE. 


429 


being  fixed  and  lapped  round  the  barrel  as  the  carriage  moves  outward,  causes  it  to  turn. 
On  the  barrel  is  a  spur  wheel  which  gears  into  a  spur  pinion  on  the  tin  roller  shaft,  (these 
wheels,  being  under  the  frame  side,  are  not  seen  in  the  drawing.)  The  spur  pinion  is  loose 
on  the  tin  roller  shaft,  and  as  the  carriage  comes  out  it  turns  loosely  thereon,  but  as  the 
carriage  goes  in,  the  chain  i^  turns  the  barrel  round,  and  with  it  the  spur  pinion.  A  catch 
on  a  stud  fixed  in  the  side  of  the  pinion,  at  that  time  taking  into  a  tooth  of  the  ratchet 
wheel  i  fast  on  the  tin  roller  shaft,  the  motion  of  the  spur  pinion  is  communicated  to  the 
tin  roller  shaft,  and  thence  to  the  spindles,  causing  the  thread  or  yarn  spun  during  the  com 
ing  out  of  the  carriage  to  be  wound  on  the  spindles,  in  the  form  of  the  cop,  while  the  car- 
riage goes  in.  At  the  commencement  of  the  formation  of  a  set  of  cops,  when  the  yarn  is 
being  wound  on  the  bare  spindles,  the  spindles  require  to  have  a  greater  number  of  turns 
given  to  them  than  they  do  when  the  cop  bottom  is  formed.  To  produce  this  variation, 
the  following  means  are  employed  : — At  the  commencement  of  each  set,  the  screw  in  the 
radial  arm  is  turned  so  as  to  turn  the  nut  i'  to  the  bottom  of  the  screw,  where  it  is 
near  to  the  shaft  on  which  the  quadrant  moves  ;  consequently  little  or  no  motion  is  given 
to  the  chain,  and  the  carriage,  as  it  goes  in,  causes  the  chain  to  be  drawn  oft'  the  band. 
As  the  formation  of  the  cop  bottom  proceeds,  the  screw  is  turned  and  the  nut  is  raised  ;  by 
which  means  a  less  quantity  of  chain  is  drawn  off"  the  barrel ;  the  chain,  at  ihe  point  of 
attachment,  gradually  following  the  carriage  as  it  goes  in. 

During  the  going  in  of  the  carriage  the  quadrant  is  drawn  down  or  made  to  follow  the 
carriage  by  the  chain  pulling  it,  the  speed  at  which  it  is  allowed  to  descend  is  regulated  by 
tlie  motion  of  the  carriage  ;  the  quadrant,  during  the  going  in  of  the  carriage,  through  the 
pinion  g'',  shafts  g^  and  g'*,  and  wheels  g\  G",  g''  and  g*  driving  the  drawing-out  shaft. 

When  the  carriage  has  completed  its  inward  run,  the  bowl  a*  comes  in  contact  with  the 
piece  a'^,  and  depresses  it  and  the  end  of  the  lever  k^  to  which  it  is  attached,  and  also  the 
slide  c,  which  then  allows  the  catch-box  k'  to  be  put  in  contact,  and  causes  the  cam  shaft 
to  make  another  half  revolution.  During  this  half  revolution  of  the  cam  shaft,  the  cams 
cause  the  catch-box  m  to  be  put  in  contact,  and  the  driving  strap  to  be  traversed  on  to  the 
fast  pulley,  and,  by  the  latter  movement,  the  catch-box  h"  is  taken  out  of  gear  and  the 
winding-in  motion  of  the  scrolls  ceases,  and  the  carriage  will  again  commence  its  outward 
run,  and  with  it  the  spinning  of  the  thread. 

Fi(/.  211  is  a  view  of  a  beetling  machine,  made  by  Mr.  Jackson,  of  Bolton,  for  the  firm 


211 


JIL 


a= 


430  COTTON  MANUTACTUEE. 

of  Messrs.  Bridson,  Son  &  Co.,  of  that  town,  a  is  the  beetling  roller,  and  b,  c  are  the 
rolls  of  cloth  which  are  to  receive  the  peculiar  finish,  which  beetling  alone  can  give  to  cot- 
ton cloths. 

Although  this  is  a  very  simple  machine,  yet  it  is  questionable  if  it  or  any  other  modern 
invention  can  effectually  take  the  place  of  the  old-fashioned  but  useful  upright  wooden 
beetle. 

The  following  extracts  from  the  circular  of  Messrs.  Leariug  &  Co.  present  so  complete 
a  view  of  the  state  of  the  cotton  trade  at  this  date,  that  they  are  now  and  will  continue  of 
much  interest  and  import;mce  : — 

"  Mobile,  September  let,  1858. 

"  The  close  of  the  commercial  year,  ending  the  31st  of  August,  gives  the  total  receipt 
of  cotton  at  all  the  American  ports  as  3,113,9(32  bales,  against  2,039,679  bales  of  the  year 
previous.  Of  the  past  year's  receipts,  England  took  1,809,966  bales,  the  rest  of  Europe 
7sO,489  bales,  while  the  United  States  bought  595,562  bales.  This  shows  an  increase  to 
Great  Britain,  a  falling  off  in  the  exportatious  to  the  Continent  and  other  parts,  and  a  dimin- 
ished consumption  in  the  United  States. 

"  It  is  important  to  remark,  that  this  falling  off  in  the  exportation  to  the  Continent  of 
Europe,  and»also  the  home  consumption,  does  not  necessarily  involve  any  actual  diminution 
in  consumption ;  because,  what  the  Continent  of  Europe  failed  to  take  direct  of  the  raw 
material,  will  be  represented  by  increased  re-exports  from  Liveipool,  and  increased  demands 
for  yarns  from  the  English  spinner ;  and  what  the  United  States  failed  to  buy  and  work  up, 
has  been  bought  and  will  be  worked  up  by  others.  Consequently,  although  on  the  surface 
a  falling  off  in  consumption  may  appear  as  in  regard  to  the  Continent  and  America,  the 
demand  will  be  supplied  through  othei^ilmnnels  in  a  proiiortionately  increased  ratio. 

"  Added  to  this  established  consumption,  is  the  natural  increase  throughout  the  world 
in  excess  of  supply.  The  opening  up  of  China,  and  the  mutiny  in  India,  which,  by  inter- 
rupting not  only  the  growth  of  cotton  there,  but  also  the  weaving  industry  of  the  natives, 
have  increased  the  demand  for  yarns  and  cloths  from  England,  conspire  to  add  to  the  de- 
mand for  our  staple.  The  last  large  receipts  of  Suiats  from  India  occurred  during  the 
blockade  of  the  Chinese  ports ;  consequently  the  exports  from  Bombay,  usually  sent  to 
China,  were,  by  this  cause,  thrown  upon  the  Liverpool  market,  induced  also  by  the  attrac- 
tion of  high  prices. 

"  Tlie  universal  prevalence  of  the  panic,  the  long-continued  prostration  in  trade,  and 
the  working  of  short  time,  have  reduced  the  stocks  of  goods  everywhere  ;  and  this  special 
feature  is  met  in  the  markets  of  the  raw  material  with  a  similar  exhaustion.  The  reports 
in  regard  to  the  growing  crop  are  conflicting.  What  with  the  certain  effect  of  the  floods  in 
the  Mississippi  Valley,  and  tlie  information  from  various  sources  in  regard  to  the  injury  the 
young  plant  is  receiving,  serious  apprehensions  are  entertained  of  another  comparatively 
short  crop.  It  is  worthy  of  remark  that  conflicting  interests  generally  take  opposite  views 
in  regard  to  the  future  prospects  of  the  growing  crop.  The  hopes  and  apprehensions  of  the 
buyer  and  seller,  combined  with  the  natural  disposition  to  embrace  that  view  which  is  dic- 
tated by  self-interest,  must  continue  to  characterize  all  the  repoits  upon  cotton,  cither  from 
Europe  or  this  side.  But  it  is  well  for  our  European  friends  to  have  clearly  before  them 
the  utmost  cotton  crop  America  can  yield  under  the  best  possible  conditions  embraced  in  a 
wide  area  under  cultivation,  an  early  spring,  a  good  stand  in  the  field,  a  propitious  summer, 
and  a  favorable  autumn.  Accepting  these  rare  conditions  as  embraced  within  any  one 
year,  it  is  simply  impossilJe  for  the  United  States  to  produce  for  commercial  purposes, 
with  the  present  supply  of  labor,  beyond  a  certain  amount  of  cotton.  As  the  best  staiTdard 
by  which  to  arrive  at  this  capacity  for  '  utmost  production '  in  America,  we  select  the  year 
18.55-56.  The  commercial  crop  that  season  was  3,527,845  bales,  from  which  must  be  de- 
ducted for  cotton  remaining  over  from  the  year  previous,  on  hand  in  the  interior,  or  in 
stock  on  the  seaboard,  say  250,000  bales.  This  leaves  as  the  'actual'  or  'new'  crop  of 
1855-56  the  reduced  amount  of  3,277,845  bales.  The  season  here  taken,  will  be  remeni- 
bered  as  the  most  fiivoraljle  ever  known  to  a  large  production.  It  was  also  stimulated  in 
its  growth  by  previously  ruling  high  prices.  Accepting  as  correct  the  generally-received 
data  that  the  negro  labor  force  in  the  cotton  States  increases  at  the  rate  of  five  per  cent, 
per  annum,  would  give  fifteen  per  cent,  increase  for  the  three  years,  from  1856  to  1858-59. 
This  increase  of  labor  thrown  into  the  cotton  yield  would  seem  to  indicate  3,760,000  bales 
(more  or  less)  as  the  utmost  possible  cajjacity  of  production  for  the  year  ending  1st  Sep- 
tember, 1859.  In  explanation,  it  is  woithy  of  remark  that  the  increase  upon  the  increase, 
which  we  have  not  estimated,  in  the  three  years,  would  make  the  production  even 
larger.  Yet  we  see  in  the  succeeding  years  a  falling  oft'  from  the  production  of 
1855-56  instead  of  an  advance.  The  total  commercial  crop  of  1856-57  was  only 
2,9:{9,519  bale.«,  while  the  season  just  closed  gives  the  limited  yield  of  3,113,962 
bales. 

"  The  production  of  cotton  in  America  is  not  therefore  limited  by  soil.     It  is  a  question 


COTTON  MANUFACTURE. 


431 


of  labor,  the  negroes  being  almost  exclusively  the  producers.  Now  a  negro  can  only 
'  pick '  so  many  pounds  of  cotton  a  day,  and  no  more.  There  is  a  certain  number  of 
negroes ;  and  these  cannot  be  added  to  otherwise  than  by  the  natural  increase  of  popula- 
tion already  estimated.-  They  cannot  be  increased  by  immigration.  The  cotton  picking 
season — that  is,  the  cotton  harvest — cannot  extend  beyond  a  certain  number  of  days. 
Estimating,  therefore,  the  largest  number  of  negro  laborers,  the  greatest  amount  of  cotton 
per  day  to  the  hand,  and  tiic  longest  possible  extension  of  the  harvest  or  picking  season, 
and  we  have  the  utmost  possible  production  of  the  new  crop.  As  before  stated,  the  cotton 
year  of  1855-56  presented  all  these  favorable  characteristics.  Since  then,  the  crop  has 
i)eou  reduced  in  exact  proportion  as  either  of  these  features  were  affected.  In  illustration, 
the  following  statement  is  instructive : 

"  In  1844  the  first  receipt  of  new  cotton  on  the  sea  board  was  on  the  23d  of  July,  the 
receipts  at  New  Orleans  on  the  1st  of  September  being  5,720  bales.  The  crop  that  year 
was  considered  large,  being  2,394,503  bales. 

"  In  1846  the  first  receipt  of  new  cotton  was  on  the  Yth  of  August,  and  the  receipts 
at  New  Orleans  on  the  1st  of  September  only  140  bales  !  Here  notice  the  falling  off  in  the 
total  crop  that  year,  the  same  being  only  1,778,651  bales. 

"  In  1848  we  have  a  receipt  on  the  1st  of  September  at  New  Orleans  of  2,864  bales,  and 
a  total  crop  of  2,728,596  bales. 

"In  1849  (the  succeeding  year)  we  find  the  receipts  at  New  Orleans  on  the  1st  of  Sep- 
tember to  be  only  477  bales,  and  the  crop  for  that  year  falling  off  to  2,096,706  bales  ! 

"In  1851  we  find  an  unusually  early  receipt  of  the  first  bale  and  a  receipt  of  new  cot- 
ton at  New  Orleans  ou  the  1st  of  September  of  over  3,000  bales !  The  crop  that  year  was 
the  largest  ever  grown  up  to  that  period,  being  over  3,000,000  bales ! 

"  In  1852  (the  succeeding  year)  we  find  the  receipts  at  New  Orleans  on  the  1st  of  Sep- 
tember to  be  5,077  bales,  being  the  largest  receipt  ever  known  up  to  that  time ;  followed 
in  exact  ratio  by  the  largest  crop  ever  grown,  being  3,262,882  bales. 

"  In  1853  we  have  a  late  receipt,  followed  by  a  diminished  crop. 

"  In  1854  we  have  another  small  receipt  on  the  1st  of  September,  with  a  small  total 
crop. 

"  In  1855  we  find  an  unusually  early  receipt  of  cotton,  with  the  receipts  at  New  Orleans 
on  the  1st  of  September  amounting  to  the  unexampled  figure  of  23,382  bales !  An  increased 
crop  follows  this  early  heavy  receipt,  being  over  3,500,000  bales. 

"In  1856  (the  next  year)  the  receipts  at  New  Orleans  on  the  1st  of  September  were 
only  1,166  bales,  and  the  crop,  true  to  the  principle  of  Labor,  on  which  it  depends  so 
much,  fell  to  2,933,781  bales. 

"  In  1857  the  receipt  on  the  1st  of  September  of  new  cotton  at  New  Orleans  was  only 
33  bales,  followed  by  a  short  crop. 

"  In  this  year  the  receipts  up  to  date  at  New  Orleans  figure  up  4,834  bales,  embracing, 
of  course,  the  flooded  districts. 

"  Referring  to  our  annual  tabular  statement,  it  will  be  found  that  the  ratio  of  increase 
in  consumption  keeps  pace  with  increase  of  production,  if  indeed  it  does  not  exceed  the 
latter." 

Growth  and  Conswnption  of  the  United  States. 


Total 

Consumed 

New 

„                   South 

North 

Growth  of 

and  in 

Carolina. 

Carolina. 

Slates. 

Spinners' 
bands. 

lS:39-40 

953,672  '  i:j(;,257 

445.725 

. 

292,693    313,194 

9,394 

26,900 

2,177,8.35 

291,279    1 

1S40-41 

814,630      9:3,552 

820,701 

- 

148,947  ,  227,400 

7,s65 

21,800 

1,634,945 

297,283 

mi-42 

727,658    114,416 

318.315 

. 

232,271  :  260,164 

9,737 

21,013 

1,68.3,.574  i  267,8.50 

l-i4-2-4:{ 

1,060.246  ,  ICl.iiSS 

431.714 

- 

299,491     351,658 

9,039 

15,639 

2,378,875    325,129 

1S43-44 

8:32,172  ■  145.5i!2 

467,990 

- 

25.^.597    304,870 

8,618 

15,600 

2,030,409 

346.744 

1844-45 

929,126  :  lls,69:3 

517,196 

- 

29.'5,440  '  426,361 

12,487 

2.5,200 

2,394,503 

389,006 

1845-40 

1,0:37,144  i  141,184 

421,966 

27,003 

194,911     251.405 

10,il:;7 

16,282 

2,100,.537 

422.597 

1S4G-47 

7(15,979  i  127,8.V3 

323,462 

9.317 

242, 7s9     850,200 

6.im;i 

13,991 

1,778,051 

427,967 

184T-48 

1,190,7:3:3  1  15:3,770 

436,336 

39,742 

254825  1  261.  (.52 

1.5 18 

8,952 

2,347,6:54 

.581,772 

lsi4S-49 

l,09-'5,790  !  2"0,1S6 

518,706 

88  s27 

891. .372    4,53,117 

10,041 

17,550 

2,72s..596 

518,039 

ls40-.'-.O 

781.SS6 

1M.:344 

850,952 

31,263 

.34:!,6:35    3S4265 

11,n61 

11.500 

2,096,706 

4.87,709 

is50-r)i 

9:i:3,:36y 

181,204 

451,748 

45,820 

822,376    887.075 

12,928 

20,737 

2,3.5.5,257 

404.103 

is.-,  I -52 

1,:37;3,464 

188,409 

549,449 

64,f).'-.2 

.32.5.714  I  476,614 

16.242 

20.995 

3,01.5.029 

003,029 

ls.-,2-r.:5 

1,580,875 

179,476 

5W),029 

8.^790 

849.490    46:!.208 

23,.t96 

35,.523 

.3.262.882 

671.009 

]S.'j3-.'>4 

I,:i46,925 

15.\444 

5:38,684 

110,:325 

816,011,5 

416,7.54 

11.524 

84.366 

2,930.027 

6IO,.571 

1854-55 

1.2:32.614 

1 :36,.597 

454,.'-,95 

80,7:37 

878,094 

499,272 

26.1:39 

8S.661 

2,^47,3.39 

598,534 

18.'5.5-5fi 

1,661,4:!:'.    111.104 

C.->9.738 

116.078 

389.445 

4S5.976 

'.'6  OIK 

84.67:1 

.3.517.845 

1856-57 

1,435,0  10    I:i6,:3U 

503,177 

89,882 

322.111 

897.881 

27,147 

2s.:527 

2,9:39,519 

1857-53 

1,. 576,409    122,351 

522,364 

145,286 

282,973 

406,251 

2.3,999 

34,329 

3,11:3,962 

432 

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COTTON  MANUFAOTUEE. 


433 


Price 

Of 

Cotton^ 

at  Liverpool,  at  the  dose  of 

eac^  F 

ear. 

Description. 

1840.    1    1841. 

1842.     1    1843.    j    1S44.    {    1S45.    j    1846.     |    1847. 

1848. 

d. 

d.  ^d. 

d. 

d.       d. 

d. 

rf 

d. 

rf. 

rf. 

rf.  \d. 

d.  \d. 

d. 

d. 

</.  i 

Sea  Island 

2S@36 

24@23 

24 

10i#20 

10®  20 

10+@20  !l2@24  1  7® 20 

7@16  t 

Stained  ditto  - 

-■ 

- 

- 

- 

- 

5 

10 

4 

9 

3+ 

8      6 

11     4 

8 

8+ 

<U' 

Upland  -        -        - 

6f 

7i 

1 

7} 

6}      7 

H 

5} 

oj 

4f 

3+ 

4fl  6+ 

7};  4j 

5i 

3* 

4+ 

Mobile    - 

- 

- 

- 

- 

44 

5} 

■H 

4} 

3+ 

5  i  6+ 

7 J    4| 

f>i 

3+ 

41 

Now  Orleans  - 

8+ 

9 

H 

8* 

Si      9 

4} 

7 

H 

6 

3+ 

6+    6+ 

9+    4 

0+ 

3+ 

5+ 

Pernambuco  - 

•Ji 

lOi 

Si 

10 

7i      8J 

5f 

*i+ 

4J 

tii 

5f 

OJ,   7+ 

8+    6 

7 

4f 

5* 

Bahia  and  M.aceio  - 

- 

- 

- 

5} 

6i 

4} 

H 

5* 

6  1  7+ 

Si!  5+ 

6 

4f 

•H 

Maranham 

a 

10 

!i 

n 

6J      7f 

H 

6i 

4 

b+ 

4 

6  1  6f 

8+i  4i 

0+ 

4 

•■'  1 

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. 

. 

5 

6 

4+ 

6+ 

4+ 

5i:  6i 

8  1  5} 

6+ 

4J 

•H 

Esryptian 

11 

14 

9i 

12+ 

8      lOi 

6 

8 

5 

8 

5^ 

8  j  7i 

10+1  5|. 

8 

5 

7 

Deinerara,  &c. 

11 

la 

m 

12 

Si    10+ 

- 

- 

. 

- 

-      7 

10+    5i 

8 

4+ 

5!- 

Common  West  In. 

- 

- 

- 

- 

4+ 

H 

4+ 

5f 

4 

6  1  6+ 

Si!  4} 

6 

4 

5 

Laguira,  &c.  - 

. 

. 

- 

- 

- 

4* 

M 

4 

4+ 

4 

4+    6+ 

7i 

4+ 

45 

3+ 

4 

Cartliagena     - 

- 

- 

- 

- 

- 

8J 

4i 

3 

3i 

3+ 

3+,  4i 

5i 

2J 

31 

Smyrna  - 

- 

- 

. 

- 

. 

4+ 

• 

- 

- 

- 

. 

• 

. 

. 

Surat      ... 

5i 

«i 

5 

6i    4}      5 

3i 

4f 

2f 

3+ 

2+ 

3f    4 

5+ 

2} 

4 

24 

8 

Bengal    ... 

- 

- 

... 

. 

2i 

3 

•      4 

4J 

3 

3+ 

2f 

3 

Madras   ... 

- 

- 

- 

-      - 

3+ 

4+    2i 

3+ 

2+ 

3j'  4i 

5+ 

3 

4j 

2J 

3 

Description. 

1849. 

1850.     1    1851.    1    1852. 

1853. 

1854. 

1855.    j    1856.     1    1857. 

d. 

d. 

d. 

d.  \d.       d.  d. 

<^. 

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d. 

d. 

</. 

^. 

d.  \d. 

cZ.  i      d 

Sea  Island 

'Hd 

24 

1H@24  110i@24    16®  30 

9+@34 

8@32 

7+®32  !l0i5^32  I      2S 

Stained  ditto  - 

G 

9 

T 

12  j  4      10  1  5i 

14 

4 

10 

4 

9 

4 

8  !  6 

9+   5 

s+ 

Upland   ... 

•H 

6f 

7 

8i   4        5i    4|. 

6,1 

4 

m 

3f 

6 

4+ 

6J'  6 

8  1  4 

fi+ 

Mobile    - 

i>* 

H 

i 

8i;  4        5^    4| 

6i 

4 

6+ 

3f 

6 

4V 

6  1  6 

8  !  4 

fit 

New  Orleans  - 

6* 

8 

7 

9i   4        6f    4i 

7+'  4 

7+ 

3+ 

7 

4+ 

7+;    6 

8J   4 

71 

Pernambuco  - 

«i 

7 

H 

9  1  .5}      7  j  6f 

7+   6} 

7 

6 

8 

6 

7J    7} 

8+   6J 

7?- 

Bahia  and  Maceio  - 

<ii 

H 

8^ 

8J   51      6^1  Hi 

6J    6 

<5* 

5^ 

6+ 

^ 

6f:  71- 

7+   55 

fi+ 

Maranham 

6 

6} 

a 

9k   H      7i   5J 

7+    6f 

8 

5 

7^ 

&* 

7 

71 

8.i   6i 

7f 

Peruvian 

- 

- 

- 

-  1   .        -  1    - 

- 

- 

- 

H 

6| 

5t 

7 

7+ 

7J   6i 

7 

Egyptian 

6 

9 

n 

ir  5       9  ]  5i 

13 

!^k 

13 

5 

10 

^\ 

9 

fit 

11  !  7 

9+ 

Demerara,  Ac. 

bi 

U 

7+ 

9*    5i      9  !  5i 

12 

6 

11 

S+ 

9 

5f 

7t 

fit 

9+   6 

9 

Common  West  In. 

5i 

6f 

7 

9  !  4J      6+51 

9 

5+ 

9 

4* 

8 

5 

8 

fii 

9  1  5 

6+ 

Laguira,  &c.   - 

6 

H 

7* 

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5}   5+ 

6 

5 

5f 

■"H 

6 

7 

7f!  5J 

6+ 

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H 

bi 

&i 

6  1  3        4     3L 

3f    2f 

H 

n 

3} 

3+ 

4+ 

3f 

4I   3I 

4+ 

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- 

• 

- 

-   !  3J      4'ri  4 

4i:    - 

• 

- 

. 

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4 

5 

4} 

6J    2i      4|    3J 

5  1  2+ 

4} 

2+ 

4+ 

3} 

4i   41- 

5-    .3} 

5 

Bengal    - 

- 

- 

-  :  2f      3i   .8+ 

4  !  2i 

3i    2+ 

3+ 

3 

3+    4+ 

4i    3+ 

3f 

Madras   ... 

4k 

5     4} 

fii    Cf      4  ■  3i 

4}    2J 

4+1  2+ 

4 

■^ 

4+   4J 

5f   3i 

5 

Price  of 

Water  and  Mule  Twist, 

in  Manchester,  on  the  31si  of  JDeccmhcr  in 

each  Year. 

Mule 

No. 

1840  1841  1842 

184; 

1844 

1845  1846  1847 

1848 

1840 

1850 

I.S.'il 

18,5? 

1853 

1S,'i4 

1855  1856 

1.8,57 

Twist. 

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10 

8} 

71 

6+ 

61 

c+ 

6f 

81 

6 

51 

CJ 

8+ 

6+ 

(>i 

6^ 

6} 

6+ 

'} 

7* 

Common 

12 
20 

Seconds 

81 

8+ 

71 

7} 

8 

7! 

9 

7 

fii 

71 

10 

7+ 

8 

8+ 

71 

7^ 

!  91 

8 

30 

101 

Oi 

y^ 

9 

9 

8i 

104 

8 

7J. 

9 

11 

8} 

9} 

9f 

8f 

8} 

10!- 

9 

40 

fil 

14 

13 

12J 

1-.'+ 

m 

121 

14 

Hi 

9+ 

12+ 

13 

10} 

Hi 

12 

11 

11 

12i 

12+ 

Best 
Seconds  ' 

8  L 

10  " 
12. 
20 

9 

8+ 

" 

7f 

7+ 

7J- 

9i 

6* 

5} 

71 

9 

7 

7+ 

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6} 

6} 

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7+ 

101 

9+ 

10+ 

9 

8+ 

8S    101 

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81 

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30 

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10 

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11  + 

91 

10+ 

101 

9} 

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11 

9+ 

40 

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15+ 

- 

15+ 

13+ 

13J    151 

12+ 

11 

13 

13+ 

11+ 

12 

t2i 

lU 

11  + 

13 

13 

Water 

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61 

4 

10  r 
12  J 
20 

8 

61 

61 

6+ 

6+ 

GJ 

7i 

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5 

c+ 

81 

H 

5} 

5.' 

51 

5+ 

6} 

61 

9 

81 

71 

7+ 

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n 

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7} 

71 

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30 

f'^t 

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81 

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40 

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y+ 

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V* 

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91 

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91 

9+ 

8+ 

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n* 

50 

12 

11 

11 

10+ 

11 

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8} 

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10} 

13} 

9} 

11 

11 

10 

10 

HI 

1(1+ 

60 

14+ 

12+ 

12 

12+ 

13+ 

12}    131 

10 

91 

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16+ 

16 

13+ 

14J 

16 

14?r    15} 

12 

11 

1.3+ 

IVl 

12+ 

14 

14+ 

13 

13 

11+ 

12 

80 
"1 

18+ 

17 

15+ 

16+ 

18+ 

181 

19} 

14+ 

13 

17 

191 

14+ 

161 

17 

15+ 

15 

16 

16 

10  r 
12J 
20 

9 

7} 

7+ 

7+ 

7+ 

7} 

9+ 

6} 

6+ 

7 

8} 

5} 

61 

6 

5} 

C 

71 

0} 

Best 

9} 

9i 

8+ 

8+ 

Si 

8} 

lOJ 

7} 

6+ 

8 

10 

71 

81 

7} 

7 

71 

H 

7+ 

30 

12 

10+ 

9+ 

10 

y+ 

9| 

Hi 

Si 

7 

9 

Hi 

8 

91 

Sf 

8 

8+ 

1(1 

Si 

40 

12+ 

11+ 

101 

111 

10 

10}    11} 

9 

7+ 

10 

121 

'^i 

10 

94 

8}  1 

9* 

11 

lOf 

50 

13+ 

12 

12 

11} 

12 

11}  ]••;+ 

11 

8}    111 

111 

10 

10 

11  + 

ll»+    10+ 

11} 

11 

60 

16 

16 

15 

141 

10+    13+    l.-il 

13 

10      12} 

16 

1  + 

13 

'2i 

11+    11  + 

12^ 

'M 

|70 

18+ 

18 

17 

n+ 

!'<+    16}    181 

lt+ 

12      14 

17}    13 

15 

4 

13+    13+ 

15 

11+ 

l80 

21 

20+ 

19 

19+ 

20+    2n    22j; 

16 

14     18 

20      I.H 

17      17+  1 

16     15+ 

16+ 

16+ 

Vol.  III.— 28 


434 


COTTON  MANUFACTURE. 


The  Growth,  Consumption,  and  Export  of  Cotton  from  Wie  United  States  during  the  laH 

Fifteen  Years. 


Exported  tc 

Crop  of  the 

Consumption 
in  Ihe  United 

Years. 

North  of 

States. 

Great  Britain. 

France. 

Europe. 

Countries. 

Total. 

\-yU-40 

2,394.503 

389,000 

1,439.306 

359,357 

134,51  H 

150.592 

2,083.756 

ls4o-4(J 

2,100,537 

422,597 

1,102,369 

359,703 

60,692 

118.028 

l.t;6:-i.7!)2 

1S46-4T 

1.778,051 

427.597 

830,909 

241.486 

75,6b9 

93.138 

],241,-i22 

Is-tT-iS 

2,347,034 

010,044 

1,. 324.265 

279,172 

120,343 

134,476 

1,858,201 

l'^4S-49 

2,728.590 

642,285 

1,5:37,901 

368,259 

165,458 

1.^6.226 

2.227,844 

1^9-50 

2,090,706 

613,498 

1,106,771 

289,097 

72,256 

121,001 

1,590,155 

1S50-51 

2.355,257 

485,014 

1,418,265 

301,358 

129,492 

139,595 

1,988,710 

1  Sol -52 

3.015,029 

699.003 

1,668.749 

421.375 

168,875 

184,647 

2,443.645 

IS  2-53 

3.202,882 

803,725 

1,736,800 

426,728 

171,176 

193,636 

2,528.490 

1853-54 

2,930,027 

737,236 

1,60.3,750 

874.053 

165,172 

176,168 

2,319,148 

1S54-55 

2,847,339 

706,412 

1.549,716 

409,931 

135,200 

149,367 

2,244,209 

1 S55-56 

3,527,845 

770.739 

1,921, .380 

480,  a37 

304.005 

248,578 

2,954,806 

lSo6-5T 

2,939,519 

819.936 

1,428,870 

413,857 

245,793 

164,632 

2,252,657 

1S57-5S 

3,U3,9C2 

595,562 

1,809,963 

384,002 

216,145 

181,342 

2,589,968 

Cotton  Crop  of  the  United  States. 


Xew  Orleans 

Mobile 

Florid.i 

Georgia       .        .        • 

South  Carolina  - 

North  Carolina  - 

Virginia      -        -        . 

Texas 

Tennessee,  &c.   • 

Total  crop  -        -        - 

Total  crop  of  1858,  as 

above       ... 
Crop  of  last  year 
Crop  of  year  before   - 

Increase  from  last  year 
Decrease  from  year  be- 
fore ... 


1857. 


1,435,000 

503,177 

136.344 

822,111 

397.331 

27,147 

23.733 

89.882 

9,624 


3,113,962 


3.113.962 
2,939,519 
3,527,845 


1,576,409 

522,304 

122,351 

282.973 

400,251 

23,999 

24,705 

145.286 

4,754 


2,939,519 


174,443 

413,883 


Export  to  Foreign  Forts  in  1S57-8. 


Xow  Orleans    bale; 

Mobile    -       -  '■ 

Texas      -        -  " 

Florida  -       -  " 

Savannah        -  " 

Charleston      -  " 

North  Carolina  " 

Virginia  -  " 

Baltimore       -  " 

Philadelphia  -  " 

New  York      -  " 

Boston   -        -  " 

Total       - 
Total  last  year 

Increase 


Great 
Britain. 


1,010,716 
265,404 
33,933 
25.771 
149,340 
192,251 

495 

164 

995 

110,721 

14,110 


To  France 

and  the 
Continent. 


1.809.906 
1,428,870 


381,096 


478,354 
121.56S 
16,404 

18,356 
107,153 


37,100 
1,553 


780,489 
823,787 


16,710 


1,495,070 

387.032 

50,838 

25,771 

167,700 

299,404 

495 
164 

995 

147,821 

15,663 


2  590.4.'-.5 
2,252,057 


397,800 


Consumption. 


Total  crop  of  United  States,  IS.'SS   - 
Add  Stocks  on  hand^at  the  comnience- 
ment  of  the  vcar  1st  September,  1857 : — 

In  the  southern  ports       -        -        -    2.3,.590 
In  the  northern  ports       ...    25,678 


3,113,962 


49.258 


Makes  a  .supply  of 

Deduct  the  export  to  foreign 

ports 2,590,455 

Less  foreign  included      -        -  723 


3,163,220, 


Stocks  on  hand  at  the  close  of  the  year 
1st  September,  1858: — 

In  the  southern  ports        -      57.604 
In  the  northern  ports       -      45,322 


2,589,732 


102,926 


Burnt  at  New  York  and  Baltimore,  and 
manufactured  in  Virginia    -        -        -    18,377 


■2.711,035 


Taken  for  home  use 


595,562 


ToUil  Crop  of  Bales, 


Quantity  consumed 


bands  of,  Mncufac- 
turers. 


1S57— 8 
1856—7 
18.55—6 
1854—5 
18.53— 4 
1852—3 
1851—2 
1S50-51 
l>;49-50 
1,848—9 
1847- 8 
18-16-7 
184.5—6 
1844—5 
lS4:?-4 
1<42— 3 
1841—2 
1840—1 
1839-40 
18;?N— 9 
1837—8 
1836—7 
1S:?5— 6 
1S;34— 5 
1833 — I 
1832—3 


3,11.3.962 
2,939,519 
3,527,845 
2.847,-339 
2,930,027 
3.262.882 
3,01.5,029 
2,3,55.257 
2,090,706 
2,728.596 
2..347.6:34 
1.77S.651 
2.100.537 
2,394,503 
2.030,409 
2,378,875 
1,68.3.574 
1,6.34.915 
2.177,a35 
1,360,532 
1,301,497 
1,422,930 
1..360,725 
1,254.328 
1,20.5,394 
1. 070.438 


Bales, 

819,936 
770,739 
906,412 
737,236 
803.725 
699,603 
404,108 
487,769 
518,039 
531,772 
427,967 
422,597 
889.006 
846,744 
325,129 
267,850 
297,283 
295,193 
276,018 
246,003 
222,540 
236,733 
216,888 
196,423 
194,412 


CURCUMA  ANGUSTIFOLIA.  435 

Stock  in  Ports,  and  Price  of  *'  iliddling''''  New  Orleans,  at  the  Close  of  each  Year. 


Egyptian, 
Ac. 

Equal  to 

Price  of 

Years. 

American. 

Brazil. 

East  Indies. 

West  Indies. 

ToUl. 

Week's  Con- 

Middling, 

sumption. 

3l8t  Dec. 

Bales. 

(1. 

1840 

305,000 

23,700 

98,500 

14,300 

22,500 

464,0(t0 

19 

6 

1S41 

219,600 

46,100 

157,600 

24,700 

31,400 

539,400 

24 

5i 

18J2 

283,400 

53,700 

179,900 

20,200 

22.200 

564,400 

25 

H 

1S43 

483,200 

68,300 

193,200 

12,200 

28,800 

783,700 

29 

6i 

1S44 

544,900 

62,700 

239,200 

13,700 

41,400 

901,900 

33 

4^ 

lS4o 

693.100 

52,300 

241,000 

6,100 

67,900 

1,060,400 

35 

4 

1S46 

302,800 

23,700 

157,400 

4,500 

57,400 

545,800 

18 

7i 

1S47 

239,200 

59,300 

125,100 

2,200 

26,100 

451,900 

20 

4f 

1S4S 

273.300 

68,700 

137,200 

2,600 

16,800 

498,600 

18 

4 

1849 

316,400 

95,200 

107,800 

2,000 

88,000 

559.400 

18 

6i 

1850 

273,900 

68,700 

143,400 

1,300 

35,100 

522,400 

18 

t« 

1851 

245,800 

49,500 

172,000 

1,300 

2.5,900 

494,500 

15 

4i 

1853 

360,700 

54,600 

133,100 

5,800 

10.3,200 

657,400 

18 

5i 

1S53 

308,900 

48,900 

270,600 

4.000 

85.100 

717,500 

20 

6; 

1854 

811,800 

47,500 

204,000 

4,000 

59,000 

626,300 

17 

5 

1855 

236,300 

63,100 

133,100 

3,500 

50,500 

486,500 

12 

5f 

1856 

178,130 

27,170 

99,480 

700 

27,170 

332,740 

8 

7^ 

1857 

202,430 

36,180 

191,330 

5,020 

17,550 

452,550 

12 

H 

— D.  M. 

CRYOLITE.  The  mineral  from  which  the  metal  Aluminium  is  obtained  with  the 
greatest  facility.     See  Aluminium. 

It  derives  its  name  from  Kpvos,  ice, — from  the  circumstance  of  its  being  fusible  in 
the  flame  of  a  candle.  Its  composition  is — aluminium  13'00;  sodium  32*8;  fluorine 
54-2. 

It  was  discovered  at  Arksutfiord,  in  West  Greenland,  by  Giesecke,  associated  in  gneLss 
with  galena,  pyrites,  and  spathic  iron.     It  is  now  obtained  in  large  quantities. 

CRYSTAL.  A  crystal  is  a  body  which  has  assumed  a  certain  geometric  form.  It  is 
produced  by  nature,  and  may  be  obtained  by  art. 

The  ancients  believed  quartz  to  be  water  converted  into  a  solid  by  intense  cold,  and 
hence  they  called  that  mineral  crystal,  from  KpvaraWos,  ice.  This  belief  still  lingers,  many 
persons  thinking  that  rock  crystal  is,  in  fact,  congealed  water.  The  term  crystal  is  now 
applied  to  all  solid  bodies  which  assume  certain  regular  forms.  A  crystal  is  any  solid 
bounded  by  plane  surfaces  symmetrically  arranged.  Each  mineral  has  its  own  mode  of 
crystallization,  by  which  it  may  be  distinguished,  and  also  its  own  peculiarity  of  internal 
structure. 

We  may  have  a  mineral  in  a  considerable  variety  of  external  forms,  as  pyrites,  in  cubes, 
octohedrons,  dodecahedrons,  &c.  ;  but  these  are  all  resolvable  into  a  simple  single  type — 
the  cube.  Thus  galena,  whatever  external  form  it  may  assume,  has  an  internal  culDical 
structure.  Fluor  spar,  usually  occurring  in  cubical  forms,  may  be  cleaved  into  a  regular 
octohedron.  A  little  reflection  will  enable  the  student  to  see  that  nature  in  her  simple  ar- 
rangements maintains  an  unvarying  internal  type,  upon  which  she  builds  up  her  varying 
and  beautiful  geometric  forms.  There  are  certain  imaginary  lines  which  are  called  the  axes 
of  the  crystal :  these  may  be 

Rectangular  and  equal,  as  in  the  cube. 

Rectangular  and  one  unequal,  as  in  the  right  square  prism. 

Rectangular  and  three  unequal,  as  in  the  right  rectangular  prism. 

The  three  axes  unequal,  vertical  inclined  to  one  of  the  lateral,  at  right  angles  to  the 
other,  two  lateral  at  right  angles  with  one  another,  as  in  the  oblique  rhombic  prism. 

The  three  axes  unequal  and  all  the  intersections  oblique,  as  in  the  oblique  rectangular 
prism. 

Three  equal  lateral  axes  intersecting  at  angles  of  60°  and  a  vertical  axis  of  varying 
length  at  right  angles  viith  the  lateral,  as  in  the  hexagonal  prism. 

Upon  these  simple  arrangements  of  the  axial  lines  all  the  crystalline  forms  depend,  the 
particles  of  matter  arranging  themselves  around  these  axes  according  to  some  law  of  polar- 
ity which  has  not  yet  been  developed. 

CURARINE.  An  alkaloid  existing  in  a  black  resinous  matter  called  ciirari,  used  by 
the  American  Indians  for  i)ois()iiing  their  arrows.  It  is  singular  that  while  the  curari  poison 
is  absolutely  fatal  when  introduced,  even  in  small  doses,  into  a  wound,  it  is  inert  when 
swallowed.  Its  composition  is  unknown,  but  it  appears  to  be  produced  from  one  of  tlie 
Stri/chnea'. — C.  G.  W. 

"CURCUMA  ANGUSTIFOLIA.  The  narrow  leaved  Turmeric.  (East  IndiMii  Arrow 
Root.)  This  plant  is  found  in  the  forests,  cxtentiing  from  (he  lianks  of  the  Loiia  to  Nag- 
I)ore.  At  Hhagul[)ore  the  root  is  dug  up  and  rul>lied  on  a  stone  or  l)ed  in  a  mortar,  snid 
afterwards  rubbed  in  water  witli  the  liand  and  strained  through  a  cloth  ;  tlie  feeula  having 
8ub.sided,  the  water  is  poured  off,  and  the  tikor  (feeula)  dried  for  use.     The  East  Indian 


436  CURLING  STONE. 

arrow  root  is  a  fine  white  powder,  readily  distinguishable,  both  by  the  eye  and  the  touch, 
from  West  Indian  arrow  root.  To  the  eye  it  somewhat  resembles  a  finely-powdered  salt,  (as 
bicarbonate  of  soda  or  Rochelle  salt.)  When  pinched  or  pressed  by  the  fingers,  it  wants 
the  firmness  so  characteristic  of  West  Indian  arrow  root,  and  it  does  not  crepitate  to  the 
same  extent  when  rubbed  between  the  fingers. — Percira. 

At  Travancore  this  starch  forms  a  large  portion  of  the  diet  of  the  inhabitants. 

CURLING  STONE.  A  stone  used  in  Scotland  in  playing  the  national  game  of  curling, 
which  is  practised  upon  the  ice  during  the  winter.  The  stone  is  made  of  some  hard  pri- 
mary rock.  That  of  Ailsa  Craig,  in  the  Firth  of  Clyde,  is  very  celebrated.  Ailsa  Craig 
consists  of  a  single  rock  of  grayish  compact  felspar,  with  small  grains  of  quartz,  and  very 
minute  particles  of  hornblende. — Bristoiv. 

CYANATES.  The  combinations  of  the  various  bases  with  cyanic  acid,  (C'lINO'.)  The 
cyanate  of  potash,  C"NKO^,  is  employed  for  the  preparation  of  artificial  urea.  There  are 
two  modes  of  preparing  cyanate  of  potash,  both  of  which  yield  a  good  product.  The  first 
is  that  of  Clemm,  the  second  of  Liebig.  1.  8  parts  of  ferrocyanide  of  potassium  and  3 
parts  of  carbonate  of  potash  are  intimately  mixed  and  fused,  care  being  taken  not  to  urge 
the  heat  too  much.  The  fluid  mass  is  allowed  to  fall  somewhat  in  temperature,  but  not  to 
such  an  extent  as  to  solidify  ;  15  parts  of  red  lead  are  then  added  by  small  portions.  The 
crucible  is  now  to  be  reheated  with  stirring,  then  removed,  and  the  contents  poured  on  to 
a  clean  iron  plate.  2.  The  cyanide  of  potassium  of  commerce  (prepared  by  the  method 
described  in  the  article  under  that  head)  is  to  be  melted  in  an  iron  crucible  or  ladle,  and 
3^^  parts  of  dry  litharge  in  fine  powder  are  to  be  added  with  constant  stirring.  When 
the  lead  has  all  collected  at  the  bottom,  the  whole  is  poured  on  to  an  iron  plate.  The 
mass  obtained  by  either  of  the  above  processes  is  to  be  reduced  to  powder,  and  boiled 
with  repeated  quantities  of  alcohol,  until  no  more  cyanate  is  extracted.  This  may  be  known 
when  the  alcohol  filtered  from  the  residue  no  longer  yields  crvstals  of  cyanate  in  cooling. 
— C.  G.  W. 

CYANIDES.  The  combinations  of  cyanogen  with  metals  or  other  bodies.  It  has  been 
remarked  in  the  article  Hydrocyanic  Acid  that  cyanogen,  C'N,  is  a  compound  salt  radical, 
analogous  to  the  halogens  chlorine,  iodine,  and  bromine.  Like  the  latter  it  unites  with 
metals  without  the  intervention  of  oxygen,  and  with  hydrogen  to  form  a  hydracid  corre- 
sponding to  the  hydrochloric,  hydriodic,  and  hydrobromic  acids.  The  cyanides  are  both  an 
important  and  interesting  class  of  salts.  The  most  important  is  the  cyanide  of  potassium. 
The  latter  is  formed  under  a  great  variety  of  circumstances,  especially  where  carbonate  of 
potash  is  heated  in  contact  with  carbonaceous  matters.  The  nitrogen  to  form  the  cyanide 
in  the  greater  number  of  instances  is  principally,  and  in  a  few  entirely,  derived  from  the 
atmosphere.  Many  chemists  have  experimented  on  this  subject,  and  their  results  are  by  no 
means  in  harmony ;  but  thus  much  is  certain,  that  success  or  failure  depends  solely  upon 
the  circumstances  under  which  the  experiments  are  conducted.  It  has  been  shown  that, 
when  carbonate  of  potash  mixed  with  charcoal  prepared  from  sugar  (see  Carbon)  is  exposed 
to  a  very  high  temperature  in  a  current  of  nitrogen  gas,  the  potash  in  the  carburet  is,  at 
times,  absolutely  converted  into  cyanide,  not  a  trace  of  carbonic  acid  remaining.  Ex- 
periments of  this  class,  when  made  with  animal  charcoal  or  coal,  are  less  conclusive  because 
those  matters  contain  nitrogen.  But  even  then  the  amount  of  cyanogen  found  is  out  of 
proportion  to  the  quantity  of  nitrogen  in  the  coal  or  other  carbonaceous  matters.  In  fact 
it  would  seem  that  the  presence  of  a  certain  quantity  of  nitrogen  in  the  coal,  &c.,  exercises 
a  predisposing  tendency  on  the  nitrogen  of  the  air  so  as  to  induce  its  combination  with  car- 
bon with  greater  facility  than  would  be  the  case  if  pure  carbon  were  employed.  Cyanide 
of  potassium  has  been  found  on  more  than  one  occasion  oozing  from  ajjcrtures  in  iron- 
smelting  furnaces.  In  fact  it  is  produced  in  such  abundance  at  one  furnace  in  Styria  as  to 
send  into  the  market  for  sale  to  electro-platers.  Cyanide  of  potassium  is  largely  prepared 
for  the  use  of  electro-platers  and  gilder.s.  The  proportions  of  the  materials  used  are  those 
of  Liebig,  who  first  made  known  the  process.  The  modes  of  manipulation,  however,  differ 
in  the  details  in  all  laboratories.  The  following  method  can  be  recommended  from  the  ex- 
perience of  the  author  of  this  article  as  giving  a  white  and  good  product.  It  can,  more- 
over, be  worked  on  a  very  large  scale.  The  ferrocyanide  of  potassium  and  salt  of  tartar 
are  to  be  separately  dried,  pulverized,  and  sifted  through  cane  sieves.  The  salt  of  tartar 
must  be  free  from  sulphates.  To  8  parts  of  dry  fen-ocyanide  of  potassium  3  of  dry  salt  of 
tartar  are- to  be  added,  and  the  two  are  to  be  incorporated  by  sifting.  A  large  and  strong 
iron  pot  is  then  to  be  su.spended  by  a  chain  from  a  crane,  in  such  a  position  that  it  can  be 
lowered  into  the  furnace  and  raised  with  ease  ;  there  must  also  be  an  arrangement  to  en- 
able the  pot  to  be  arrested  at  any  desired  height.  The  pot  being  heated  to  redness,  the 
mixture  is  to  be  thrown  in  by  small  portions  until  the  vessel  is  half  full ;  the  heat  being  al- 
lowed to  rise  gradually  until  the  whole  flows  pretty  quietly.  During  the  fusion  the  con- 
tents are  to  be  stirred  with  a  clean  iron  rod  to  promote  the  aggregation  of  the  spongy  sedi- 
ment. As  soon  as  the  rod,  on  being  dipped  into  the  fused  mass  and  removed,  brings  with 
it  a  pure,  white,  porcelain-like  product,  the  operation  may  be  regarded  as  terminated,  and 


CYANOGEN. 


437 


the  pot  is  to  be  raised  from  the  fire  by  means  of  the  crane  and  sling  in  a  slightly  inclined 
position.  One  of  the  operators  now  liolds  a  large  clean  iron  ladle  under  the  edge  of  the 
pot,  while  another  elevates  the  latter  with  the  aid  of  tongs,  so  that  the  ladle  becomes  filled. 
The  contents  of  the  first  ladle  are  then  poured  olf  into  another  held  by  the  assistant  who 
tilted  the  pot.  The  latter  then  pours  the  contents  of  his  ladle  into  a  large,  shallow,  and 
brilllautly-clcan  brass  basin  standing  in  another  containing  a  little  water  so  as  to  cool  the 
fused  cyanide  rapidly.  Extreme  care  must  he  taken  to  prevent  even  the  smallest  drop  of 
water  from  finding  its  way  into  the  brass  vessel,  because  on  the  hot  cyanide  coming  in  con- 
tact with  it  an  explosion  would  occur,  scattering  it  in  every  direction,  to  the  great  danger 
of  the  persons  in  the  vicinity.  The  two  ladles  are  to  be  kept  very  hot,  by  being  held  over 
the  fire  until  wanted,  in  order  to  prevent  the  cyanide  from  chilling  until  it  is  poured  into 
the  brass  basin.  The  latter  should  be  about  18  inches  in  diameter  and  1^  deep.  It  should 
be  quite  flat-bottomed.  The  object  of  so  many  pourings  off  is  to  prevent  any  of  the  sedi- 
ment from  finding  its  way  into  the  product,  and  thus  causing  black  specks  in  it.  The  pot, 
on  being  emptied  as  far  as  convenient,  is  to  have  the  sediment  removed  and  a  fresh  charge 
inserted.  As  soon  as  the  coke  of  cyanide  is  cool,  it  is  to  be  broken  up  into  moderate-sized 
pieces  and  placed  in  dry  and  well-closed  jars. 

The  cyanide  of  potassium  possesses  great  points  of  interest  for  the  technical  and 
theoretical  chemist.  It  is  the  salt  from  which  an  immense  number  of  compounds  of  im- 
portance may  be  obtained.  Very  large  quantities  are  made  for  the  purpose  of  preparing 
the  auro-  and  argento-cyanides  of  potassium  for  the  electro-platers  and  gilders. 

Auro-ci/anide  of  potassium  is  capable  of  being  formed  in  several  ways.  The  following 
are  convenient  processes.  The  selection  of  a  mode  of  preparing  it  will  depend  upon  the 
circumstances  under  which  the  operation  is  situated.  1.  By  the  battery.  This  process  is 
perhaps  the  most  generally  convenient  and  economical  for  the  electro-gilder.  A  bath  is 
prepared  by  dissolving  the  best  commercial  cyanide  of  potassium  in  good  filtered  or  distilled 
water.  The  best  salt  is  tliat  sold  under  the  name  of  "gold  cyanide."  A  Daniell's  battery 
of  moderate  size  being  charged,  two  plates  of  gold  are  attached  to  wiresf  and  connected 
with  it.  The  larger,  which  is  to  be  dissolved,  is  attached  to  the  positive,  and  the  smaller, 
which  need  be  but  the  size  of  a  flattened  wire,  to  the  negative  pole.  The  action  of  the  bat- 
tery is  kept  up  until  the  desired  amount  is  dissolved.  It  is  easy  to  remove  the  plate  used, 
dry  and  weigh  it  at  intervals  so  as  to  know  the  proper  time  to  stop  the  operation.  2.  Te- 
roxide  of  gold  (prepared  with  magnesia)  is  to  be  dissolved  in  a  solution  of  cyanide  of 
potassium. 

Argento-cijanide  of  potassium. — This  solution  is  easily  prepared  for  the  electro-plater 
by  the  following  process :  Metallic  silver  is  dissolved  in  nitric  acid  and  the  solution  evapo- 
rated to  dryness.  The  residue  is  dissolved  in  distilled  water  and  filtered.  To  the  solution 
cyanide  of  potassium,  dissolved  in  distilled  water,  is  added,  as  long  as  precipitation  takes 
place,  but  no  longer.  The  precipitate  is  filtered  off  on  calico  strainers,  and  well  washed 
with  distilled  water.     It  is  then  to  be  dissolved  in  solution  of  cyanide  of  91  la 

potassium  and  diluted  to  the  desired  strength.  The  solution  is  frequently 
dark-colored  at  first,  but  it  becomes  colorless  in  a  few  hours,  and  should 
then  be  filtered  from  a  small  black  precipitate  which  will  be  obtained. 
Many  operators  neglect  the  filtration  and  washing  of  the  precipitated  cy- 
anide of  silver,  and  merely  continue  the  addition  of  the  solution  of  cyanide 
of  potassium  to  the  nitrate  of  silver  until  the  precipitate  at  first  formed  is 
re-dissolved.  The  first  method  is  however  to  be  preferred.  Some,  instead 
of  precipitating  with  cyanide  of  potassium,  do  so  with  solution  of  common 
salt,  and  then,  after  washing  off  the  precipitated  chloride  of  silver,  dissolve 
it  in  cyanide  of  potassium.  Argento-cyauide  of  potassium  can  also  be  pre- 
pared with  the  battery  by  the  process  mentioned  under  auro-cyanide  of 
potassium ;  this  method  is  so  convenient  where  the  proper  apparatus  is  at 
hand,  that  few  professional  electro-platers  would  use  any  other  method. 
Daguerreotype  artists  who  silver  their  plates,  or  rather,  re-silver  them, 
would  find  the  battery  process  too  cumbersome,  and  should,  therefore, 
use  a  solution  of  argento-cyanide  of  pota^ssium  prepared  by  the  first 
method. 

In  order  to  suspend  Daguerreotype  plates  in  the  bath,  the  little  con-' 
trivance  figured  in  the  margin,  fig.  21  la,  will  be  found  most  convenient.  It  merely  con- 
sists of  pieces  of  copper  wire  twisted  together  and  fcjrmed  into  a  grapnel  at  the  lower  end. 
It  acts  like  a  spring,  and  liolds  the  plate  so  firmly  that  there  is  no  fear  of  its  falling  out, 
even  if  the  apparatus  be  subjected  to  severe  vibration. — C.  G.  W. 

CYANIDE  OF  POTASSIUM.     See  Cyanides. 

CYANOGEN,  C'N.  A  compound  salt  radical,  analogous  in  its  character  to  chlorine 
and  the  other  halogens.  It  was  the  first  body  discovered  possessing  the  characters  of  a 
compound  radical,  and  the  investigations  made  upon  it  and  its  derivations  have  thrown 
more  light  upon  the  constitution  and  proper  mode  of  classifying  organic  substances  than 


438 


CYMOPHANE. 


any  other  researches  whatever.  In  consequence  of  its  acting  in  all  its  compounds  as  if  it 
were  a  simple  body  or  element,  chemists  generally  have  acquired  the  habit  of  designating 
it  by  the  symbol  Cy.  Like  the  haloids  it  combines  with  hydrogen  to  form  an  acid,  and 
with  metals,  without  the  necessity  for  the  presence  of  oxygen.  For  a  few  illustrations  of 
its  analogies  with  chlorine,  &c.,  see  Hydrocyanic  Acid.  In  the  article  Cyanides  several 
of  the  conditions  under  which  it  is  formed  have  also  been  pointed  out.  The  modern  French 
chemists  of  the  school  of  Gerhardt  very  justly  regard  cyanogen  in  the  light  of  a  double 
molecule,  thus,  Cy  Cy,  or  C^N^  The  reason  of  this  is  because  most  of  the  phenomena  of 
organic  chemistry  are  more  easily  explained  by  the  use  of  four-volume  formula;  than  any 
others.  This  latter  mode  of  condensation  has  been  shown  by  M.  Wortz,  in  his  admirable 
work  on  the  compound  radicals,  to  undoubtedly  exist  in  the  case  of  radicals  belonging  to 
the  strict  hydrogen  type,  not  as  ethyle  and  its  homologues ;  and  numerous  theoretical  and 
experimental  results  are  in  favor  of  the  supposition  that  all  radicals  in  the  free  state  are 
binary  groups. 

If  we  assume  the  truth  of  the  above  hypothesis,  we  shall  regard  cyanogen  in  the  free 
state  as  a  cyanide  of  cyanogen,  analogous  to  hydrocyanic  acid,  which  is  a  cyanide  of  hy- 
drogen. 

Cyanogen  may  very  conveniently  be  prepared  by  heating  cyanide  of  mercury  in  a  retort 
of  hard  glass.  A  considerable  quantity  of  the  gas  is  given  off,  but  a  portion  remains  be- 
hind in  the  state  of  paracyanogen.  The  latter  substance  is  a  black  matter,  the  constitution 
of  which  is  l)y  no  means  understood.  It  has,  however,  the  same  composition  in  the  bun- 
dled parts  as  cyanogen  itself,  and  is  therefore  isomeric  with  it. 

Cyanogen  is  a  colorless  combustible  gas  with  a  sharp  odor.  Its  density  is  1 'SI.  Hauy 
requires  for  two  volumes  1"80.  If  cooled  to  a  temperature  of  between  — 13°  and  — 22°  F., 
it  liquefies  into  a  transpaient,  colorless,  and  very  mobile  fluid  having  a  specific  gravity  of 
0'866.  A  little  below  22'  the  fluid  congeals  to  a  mass  resembling  ice.  The  flame  of  cy- 
anogen is  of  a  pale  purple  or  peach  blossom  color. 

Some  of  the»proporties  of  cyanogen  are  very  remarkable,  and  quite  distinct  from  those 
of  the  true  halogens.  For  instance,  it  combines  directly  with  aniline  to  produce  a  body 
having  basic  properties.  The  latter  is  called  cyaniline,  and  is  formed  by  th*  coalescence 
of  two  molecules  of  c.vanogen  with  two  of  aniline,  the  resulting  formula  being,  consequently, 
C^^II^N*.  There  are  a  variety  of  singular  compounds  produced  by  the  action  of  cyanogen 
and  its  halogen  compounds  upon  aniline ;  they  have  been  studied  with  remarkable  skill  by 
Hofmann.— C.  G.  W. 

CYMOPHANE.  A  variety  of  Chrysoberyl,  which  exhibits  a  peculiar  milky  or  opales- 
cent appearance.  When  cut  en  cabochon,  it  shows  a  white  floating  baud  of  light,  and  is 
much  prized  as  a  riag  stone.---H.  W.  B. 

J> 

DAGUERREOTYPE.  The  progressive  ad^-ance  of  this  branch  of  the  photographic  art, 
though  of  great  interest,  cannot  be  dwelt  on  in  this  place.  Those  who  are  interested  in  the 
inquiry,  will  find  the  information  fully  detailed  in  IlunVs  Manual  of  Photocjrapliy,  5th  edi- 
tion, 1857.  It  will  1)0  sufficient  in  this  work  to  detail  the  more  important  improvements 
which  have  become  generally  adopted.  The  first  advance  of  real  importance  was  made  by 
Mr.  Towson,  of  Devonport,  who  has  since  that  time  distinguished  himself  by  the  introduc- 
tion of  his  system  of  Great  Circle  Railing.  Mr.  Towson  suggested  the  use  of  enlarged 
lenses,  and  by  acting  with  such,  Dr.  Draper,  of  New  York,  was  the  first  to  procure  a  por- 
trait from  the  life.  Still  this  was  a  tedious  process,  but  in  1840  Mr.  Goddard  proposed  the 
use  of  bromine  of  iodine,  by  which  infinitely  increased  sensibility  was  obtained.  From  that 
time  the  Daguerreotype  was  generally  employed  for  portraiture,  until  the  facilities  of  the 
collodion  process  drove  it  fiom  the  field. 

The  improved  manipulation  now  resolves  itself  into 

Carefidly  polishing  the  silver  plate,  and  the  application  finally  of  the  highest  polish  by 
the  use  of  a  buffer,  the  best  form  being  that  employed  by  M.  Claudet. 

lu  a  box  on  a  roller,  to  which  there  is  a  handle,  ^^(/.  212,  is  placed  a  long  piece  of  drab- 


212 


:i;iiiii|l}|l|l||l|IV,i 


DAGUEEREOTYPE. 


439 


213 


colored  velvet,  which  can  be  drawn  out  and  extended  by  means  of  a  second  roller  upon  a 
perfectly  flat  table.  The  first  foot  or  two,  for  example,  is  drawn  out ;  the  plate  which  has 
already  received  its  preliminary  polishing  is  placed  face  downwards,  and  being  pressed  close 
with  the  fingers  a  rapid  circular  motion  is  given  to  it,  and  in  a  few  minutes  it  receives  its 
highest  lustre.  As  the  velvet  becomes  blackened  by  use,  it  is  rolled  off,  the  portion  re- 
maining in  the  box  being  always  perfectly  clean  and  ready  for  use. 

The  iodizing  process  follows :  and  for  this  purpose  a  box  similar  to  that  represented  will 
be  found  to  be  very  convenient,  {Jig.  213.)  This 
iodizing  apparatus  consists  of  a  square  box  with  a 
closely-fitting  cover  g,  false  sides  are  placed  at  an 
angle  with  this  box,  a  cup  d  at  the  bottom  contains 
the  iodine,  which  is  covered  with  a  thin  gauze  screen 
J  J.  c  is  a  cover  which  confines  the  iodine  when  it  is 
not  required  for  the  plate  ;  this  dividing  the  box  into 
two  parts,  H  H,  and  k  k,  the  former  being  always  full 
of  iodine  vapor.  When  it  is  desired  to  iodize  a  plate, 
the  cover  c  is  removed,  the  silver  plate  is  placed  at 
E,  and  the  cover  g  closed. 

The  plate  is  thus  placed  in  the  iodine  box  until  it 
acquires  a  fine  straw  yellow  color.  In  another  box  is 
placed  either  bromine  or  some  one  of  the  many  ac- 
celerating fluids.  If  bromine,  or  any  bromide  is  em- 
ployed, the  plate  should  remain  until  it  becomes  of  a 
rose  color.  As  a  general  rule,  if  the  yellow  color 
produced  by  iodine  be  pale,  the  red  should  be  pale 

also ;  if  deep,  the  red  must  incline  to  violet.  The  proper  time  for  exposing  a  plate  to  any 
of  those  chemical  substances  which  are  destined  to  produce  the  sensitive  film,  must  vary 
with  the  temperature,  and  it  can  only  be  determined  by  experience.  The  sensitive  plate  is 
now  removed  to  the  camera  obscura,  for  a  description  of  which  see  Photography.  It  is 
scarcely  necessary  to  say,  that  the  plate  must  be  preserved  in  perfect  darkness  until  ex- 
posed to  the  image  in  the  camera.  A  few  seconds  when  the  plate  is  properly  prepared  will 
be  found  amply  sufficient  to  produce  the  best  effect. 

The  impression  must  be  developed  in  the  mercury  box  {fg.  214)  in  the  manner  de- 
scribed by  Daguerre.  This  mercurial  box  consists  of  a  box  mounted  on  legs,  having  a 
close-fitting  cover  a,  and  an  iron  bottom  in  which  is 
placed  the  mercury  c,  and  a  small  thermometer  f  to 
indicate  the  proper  temperature,  g  is  a  piece  of  glass 
let  into  the  side  of  the  box  through  whicti  the  Da- 
guerreotype plate  H,  fixed  in  the  frame  b,  can  be  seen. 
D  is  a  spirit  lamp,  and  i  the  platform  on  which  it 
stands.  The  subject  is  eventually  fixed  by  the  use  of 
hyposulphite  of  soda,  which  removes  the  bromo-iodido 
of  silver  and  leaves  a  picture  produced  by  the  con- 
trast between  a  combination  of  the  silver  and  mer- 
cury, and  the  surface  of  the  unchanged,  polished 
silver. 

The  application  of  chloride  of  gold  to  the  finished 
picture  was  introduced  by  M.  Fizeau. 

Chloride  of  gold  applied  to  the  picture  has  the 
effect  of  fixing  and  enlivening  the  tints.  A  small 
grate  being  fixed  by  a  clamp  to  the  edge  of  a  table, 
the  plate  is  laid  upon  it  with  the  image  uppermost, 
and  overspread  evenly  with  solution  of  chloride  of 
gold,  by  means  of  a  fine  broad  camel  hair  brush,  with- 
out letting  any  drop  over  the  edge.  A  spirit  lamp  is 
now  brought  under  the  plate,  and  moved  to  and  fro 
till  a  number  of  small  steam  bubbles  appear  upon  the 
image.  The  spirit  lamp  must  be  immediately  with- 
drawn. The  remainder  of  tlue  chloride  solution  must 
be  poured  back  into  the  phial,  to  be  used  on  another 
occasion.  It  is  lastly  to  be  washed  and  examined. 
This  operation  has  been  repeated  three  or  (bur  times 

with  the  happiest  effect  of  giving  fixity  and  force  to  the  picture.  It  may  then  be  wiped 
with  cotton  without  injury.  The  process  of  coloring  these  pictures  is  a  purely  artificial  one, 
which,  while  it  destroys  the  beauty  of  the  photograph,  does  not  in  any  way  improve  it  as  a 
picture. 

Daguerreotype  Engraving. — Several  processes  for  etching  the  Daguerreotype  plate  were 


214 


440  '  DAKAR  GUM,  or  DAMMARA  RESIN. 

introduced  with  more  or  less  success.  Professor  Grove  produced  a  few  good  engravings 
by  the  action  of  voltaic  electricity.  Berard  and  Becquerel  were  also  enabled  to  produce 
some  promising  results  by  a  similar  process.  The  following  process  by  M.  Claudet  was  car- 
ried out  to  some  extent  with  every  prospect  of  success. 

The  new  art,  patented  by  M.  A.  F.  J.  Claudet  on  the  21st  of  November,  1843,  was 
established  on  the  following  facts :  A  mixed  acid,  consisting  of  water,  nitric  acid,  nitrate 
of  potash,  and  common  salt  in  certain  proportions,  being  poured  upon  a  Daguerreotype  pic- 
ture, attacks  the  pure  silver,  forming  a  chloride  of  that  metal,  but  does  not  affect  the  white 
parts,  which  are  produced  by  the  mercury  of  the  picture.  This  action  does  not  last  long. 
Water  of  ammonia,  containing  a  little  chloride  of  silver  in  solution,  dissolves  the  rest  of 
that  chloride,  which  is  then  washed  away,  leaving  the  naked  metal  to  be  again  attacked, 
especially  with  the  aid  of  heat.  The  metallic  surface  should  have  been  perfectly  puri- 
fied by  means  of  alcohol  and  caustic  potass.  For  the  rest  of  the  ingenious  but  complex 
details,  see  NewtorCs  Journal^  C.  S.  vol.  xxv.  p.  112. — See  Actinism,  Collodion,  Pno- 

TOGRAPHY. 

DAMAR  gum,  or  DAMMARA  RESIN.  A  pale  yellow  resin,  somewhat  resembling 
copal,  and  used  like  it  in  the  manufacture  of  varnishes.  Dammara  resin  is  said  to  be  de- 
rived from  the  Pinus  dammara  alba  of  India.  A  Dammara  resin  is  also  imported  from 
New  Zealand,  which  is  the  product  of  the  Damtnara  Anstralis.  Under  the  name  of  Cow- 
die  resin,  it  is  said  to  be  used  extensively  as  a  varnish  in  America.  "  Damar  is  easily 
dissolved  in  oil  of  turpentine,  and  when  carefully  selected  is  almost  colorless ;  it  makes 
a  softer  varnish  than  mastic ;  the  two  combined,  however,  form  an  almost  colorless 
varnish,  moderately  hard  and  flexible,  and  well  suited  for  maps  and  similar  purposes." — 
Holtzapffel. 

DAMASCUS  BLADES.  The  characteristics  ascribed  to  the  real  Damascus  blades  are 
extraordinary  keenness  of  edge,  great  flexibility  of  substance,  a  singular  grain  of  fleckiness 
always  observable  on  the  surface,  and  a  peculiar  imtxki/  odor  given  out  by  any  friction  of 
the  blade,  either  by  bending  or  otherwise.  The  author  of  "  Mamifactures  in  Metals''' 
remarks : 

"  A  gentleman  who  purchased  one  of  these  blades  in  the  East  Indies  for  a  thousand 
piasters,  remarked  to  the  writer  of  this  volume  that,  although  the  instrument  was  very  flex- 
ible, and  bore  a  very  keen  edge,  it  could  not  with  safety  be  bent  to  more  than  45°  from  the 
straight  shape,  and  it  was  not  nearly  so  sharp  as  a  razor,  yet,  wielded  by  a  skilful  hand,  it 
would  cut  through  a  thick  roll  of  sail-cloth  without  any  apparent  difficulty ;  a  feat  which 
could  not  be  performed  with  an  ordinary  sword,  nor,  it  should  be  observed,  by  the  sabre 
itself  in  an  ordinary  hand,  though  the  swordsman  who  tried  it  could,  it  appears,  do  nearly 
the  same  thing  with  a  good  European  blade." 

Emerson,  in  his  letters  from  the  JJgean,  says:  "I  have  seen  some  blades  (scymitars) 
which  were  valued  at  200  or  300  dollars ;  many  are  said  to  be  worth  triple  that  sum,  and 
all  retain  the  name  of  Damaxcui^,  though  it  is  by  no  means  likely  tliat  they  have  been 
manufactured  there.  The  twisting  and  intertwisting  of  the  fibres  of  the  metal  are  consid- 
ered as  the  tests  of  excellence,  but  I  have  never  seen  any  possessed  of  the  perfume  said  to 
be  incorporated  with  the  steel  in  the  real  Damascus  blade." 

The  production  and  use  of  damask  steel  have  received  much  attention  from  the  late  Gen- 
eral Anossoff,  of  the  Corps  of  Engineers  of  the  Imperial  Russian  army,  and  Master  of  the 
Fabric  of  Arms  at  Zlataoust,  in  Siberia.  His  researches  and  successful  practice  have  be- 
come matters  of  history. 

Steel  helmets  and  cuirasses  were  formed  of  cast  and  damascened  steel,  intermixed  with 
pure  iron,  a  mixture  supposed  to  combine  toughness  and  hardness  in  the  greatest  possible 
degree. 

At  different  periods  these  works  have  been  visited,  separately,  by  two  English  travellers. 
Major  Abbott  of  the  Bengal  Artillery,  and  Mr.  Atkinson,  who  have  recorded  the  results 
•of  observation,  experiment,  and  conversational  intercourse,  and  they  state  severally 
their  conviction  that  the  damask  steel  produced  by  Anossoff'  rivalled  in  beauty  and  ex- 
cellence any  works  they  had  ever  seen  in  other  lands.  They  accord  to  Anossoff  the  honor 
of  being  the  reviver  of  the  art  of  making  damask  steel  in  Europe,  while  they  declare  the 
Russian  natural  damask  steel  is  not  approached  by  the  fabrics  of  any  eastern  nation  now 
existing. 

The  Siberian  swords  and  daggers  were  compared  and  tried  with  the  choicest  specimens, 
and  found  equal  to  the  blades  of  Damascus  and  the  sabres  of  Khorassan  ;  and  while  these 
valued  articles  might  have  l)ecn  selected  from  numbers  manufactured  by  chances  of  skill 
and  material,  Anossoff"  united  chemical  analyses  of  ores  and  steel,  and  records  of  observa- 
tions on  progressive  stages,  to  give  a  true  history  of  the  means  to  explain  and  insure  suc- 
cess. 

DAMASCUS  GUN-BARRELS.     See  Fire-Arms,  vol.  i. 

DECKLE,  name  given  by  the  paper  maker  to  a  thin  frame  of  wood  fitting  on  the  shal- 
low mould  in  which  the  paper  pulp  is  placed. 


DECOMPOSITION.  441 

DECOMPOSITION".  The  separation  of  bodies  from  each  other.  The  methods  em- 
ployed are  almost  imiumerable,  and  usually  depend  on  the  special  reactions  of  the  matters 
under  examination.  We  shall  consider  a  lew  of  the  most  striking  cases  in  both  the  grand 
divisions  of  the  science,  viz.,  inorganic  and  organic  chemistry.  In  each  instance  we  shall, 
for  the  sake  of  convenience,  subdivide  into  the  three  classes  of  acids,  alkalies,  and  neutral 
bodies.  Previous,  however,  to  this,  we  must  glance  at  some  of  the  reactions  of  which 
chemists  avail  themselves  in  separating  the  elements.  The  decomposition  of  ordinary  me- 
tallic salts,  with  tlie  view  of  making  a  qualitative  analysis  of  a  more  or  less  complex  mix- 
ture, is  a  problem,  in  general,  of  extreme  simplicity,  and  directions  for  the  purpose  are  to 
be  found  in  all  the  numerous  works  on  qualitative  analysis.  The  principle  on  which  the 
modern  methods  of  qualitative  analysis  are  founded,  is  the  separation  of  the  metals  in  the 
first  place  into  large  groups  by  certain  reagents,  and  then  by  means  of  others,  to  subdivide 
into  smaller  groups,  in  which  the  individual  metals  can  be  determined  by  special  tests. 
For  the  sake  of  simplicity,  we  shall  only  consider  the  more  commonly  occurring  metals. 
The  general  reagents,  by  which  the  first  subdivision  is  effected,  are  hydrochloric  acid,  sul- 
phuretted hydrogen,  sulphide  of  ammonium,  carbonate  of  ammonia  mixed  with  chloride  of 
ammonium,  and  finally  phosphate  of  soda.  The  substance  in  solution  is  treated  with  hy- 
drochloric acid,  by  which  mercury,  silver,  and  lead  are  removed.  The  mercury  will  only 
be  perfectly  removed  if  it  exists  entirely  in  the  state  of  a  subsalt.  Lead  is  only  partially 
precipitated,  and  will  be  subsequently  found  in  the  next  group.  The  precipitate  by  hydro- 
*  chloric  acid  is  to  be  boiled  with  water,  which  will  remove  the  chloride  of  lead,  and  leave 
the  chlorides  of  mercury  and  silver.  The  latter  may  be  separated  by  means  of  ammonia, 
which  will  dissolve  the  chloride  of  silver  and  convert  the  mercury  into  a  black  powder,  in 
which  the  metal  can  be  detected  by  special  tests.  The  fluid  filtered  from  the  precipitate 
by  hydrochloric  acid  is  to  have  a  stream  of  hydrosulphuric  acid  gas  passed  through  it  for  a 
considerable  time,  or  until  no  more  precipitation  occurs.  By  this  means  antimony,  arsenic, 
tin,  cadmium,  gold,  mercury,  silver,  lead,  bismuth,  and  copper  are  thrown  down,  and  must 
be  separated  from  each  other  by  special  processes.  The  filtrate  from  the  precipitate  by 
hydrosulphuric  acid  is  to  have  ammonia  added  in  slight  excess,  and  then  a  solution  of  sul- 
phide of  ammonium  as  long  as  any  precipitation  takes  place.  By  this  means  nickel,  cobalt, 
iron,  manganese,  zinc,  alumina,  and  chromium  are  thrown  down;  also  baryta,  strontia,  ami 
lime,  if  they  happen  to  be  in  combination  with  phosphoric,  oxalic,  or  boracic  acids,  or  if 
united  to  fluorine.  From  the  filtrate,  carbonate  of  ammonia  mixed  with  chloride  of  ammo- 
nium, precipitates  baryta,  .strontia,  and  lime.  The  filtrate  from  the  last  precipitate  can  only 
contain  magnesia,  or  the  alkalies.  The  above  brief  description  of  the  mode  of  dividing  the 
metals  into  groups  will  be  sufficient  to  give  an  idea  of  the  processes  employed  for  decom- 
posing complex  mixtures  into  simple  ones. 

Inorganic  acids  are  usually  removed  from  metals  by  converting  the  latter  into  an  insol- 
uble compound,  while  the  acid  remains  in  solution  either  in  the  free  state  or  combined  with 
a, body  of  such  a  nature  as  not  to  mask  the  reactions  of  the  acid  with  reagents.  This  is 
often  done  in  the  laboratory  by  boiling  the  metallic  salt  with  an  alkaline  carbonate.  The 
metals  are,  consequently,  either  converted  into  oxides  or  carbonates  insoluble  in  water, 
while  the  acid  unites  with  the  alkali  to  form  a  soluble  salt  capable  of  being  obtained  by  fil- 
tration in  such  a  condition  as  to  permit  the  nature  of  the  acid  to  be  made  known  by  means 
of  appropriate  tests.  It  is  usually  necessary  to  neutralize  the  solution  carefully  before  test- 
ing for  the  acid. 

It  is  seldom  necessary  in  researches  to  reduce  inorganic  alkalies  to  their  elements,  their 
constitution  being  usually  ascertained  by  converting  their  constituents  into  new  forms  capa- 
ble of  being  weighed  or  measured  with  accuracy.  If,  for  instance,  it  was  necessary  to  as- 
certain the  constitution  of  sulphuric  acid,  it  would  be  sufficient  to  determine  the  quantity 
of  baryta  contained  in  the  sulphate.  On  the  other  hand,  acids  susceptible  of  assuming, 
when  pure,  the  gaseous  condition,  may  have  their  constitution  determined  by  decomposing 
a  known  volume  with  a  substance  capable  of  combining  with  one  ingredient  and  libciating 
the  other  in  the  gaseous  state.  Thus  hydrosulphuric  acid  may  be  analyzed  by  heating  it 
with  potassium,  which  will  remove  the  sulphur  and  liberate  the  hydrogen. 

In  decomposing  inorganic  alkalies  with  the  view  of  separating  the  metals  contained  in 
them,  we  usually  have  to  avail  ourselves  of  very  powerful  affinities.  This  arises  from  the 
fact,  that  the  substances  in  question  are,  generally,  produced  by  the  union  of  a  metal  with 
oxygen,  the  metal  having  so  strong  a  tendency  to  combine  with  that  element,  that  mere 
exposure  to  the  air  is  sufficient  to  determine  their  union  into  a  compound  of  great  stability. 
In  order,  therefore,  to  decompose  the  alkalies  of  this  class,  it  is  necessary  to  find  some  sub- 
stance having  a  powerful  tendency  to  combine  with  oxygen  under  certain  conditions.  Now 
it  has  been  found  that  carbon,  if  raised  to  an  exceedingly  high  temperature,  and  employed 
in  great  excess,  is  capable  of  removing  the  oxygen,  even  from  such  bodies  a.s  potassium  and 
sodium,  the  affinity  of  which  for  oxygen  is  very  great. 

Inoi'ganic  neutral  bodies  are  generally  decomposed  either  by  the  ordinary  processes  of 


442  DECOMPOSITION. 

analysis,  or,  where  the  neutrahty  arises  from  the  substance  under  examination  bein"-  a 
compound  of  an  acid  and  a  base,  by  separating  the  two  by  treatment  with  a  reagent  capable 
of  combining  with  one  to  the  exclusion  of  the  other.  This  is  a  process  frequently  available 
in  quantitative  analysis.  As  an  illustration  we  may  take  the  decomposition  of  the  carbo- 
nates by  a  mineral  acid  in  an  apparatus  which  permits  the  carbonic  acid  set  free  to  be  accu- 
rately estimated  by  weighing.  (See  Carbonates.)  Another  instance  of  the  decomposition 
of  a  neutral  body,  by  treating  it  with  a  substance  capable  of  combining  with  one  of  the 
constituents  and  separating  the  other  in  a  free  state,  is  the  decomposition  of  sulphate  of 
potash  by  baryta.  If  a  solution  of  the  salt  be  boiled  with  excess  of  solution  of  baryta,  sul- 
phate of  baryta  is  produced  and  caustic  potash  set  free.  The  excess  of  baryta  is  removed 
by  boiling  in  the  air  until  the  whole  of  the  latter  base  is  converted  into  the  insoluble  carbo- 
nate. A  precisely  analogous  process  is  the  ordinary  mode  of  preparing  caustic  potash  by 
boiling  its  carbonate  with  quicklime. 

Neutral  bodies  are  frequently,  however,  so  constituted  that  the  neutrality  does  not  arise 
from  the  circumstance  of  an  acid  being  saturated  with  a  base,  but  from  the  energies  of 
two  elements  being,  to  some  extent,  satisfied  by  the  fact  of  their  being  in  combination. 
Thus,  water  is  a  neutral  substance,  nevertheless  it  may  be  decomposed  by  a  variety  of 
processes,  several  of  which  are  susceptible  of  quantitative  precision.  In  the  first  place, 
it  may  be  decomposed  by  passing  steam  over  a  metal  capable  of  uniting  with  its  oxygen 
with  liberation  of  the  hydrogen.  It  may  also  be  electrolyzed  and  the  two  gases  separately 
obtained. 

Organic  or  inorganic  neutral  salts  may,  at  times,  be  very  completely  and  simply  decom- 
posed by  means  of  the  battery.  Not  only  are  the  various  processes  in  electro-metallurgy 
founded  on  this  principle,  but  it  has  even  been  practically  applied  to  the  quantitative  esti- 
mation of  the  metals  in  ores.  The  electrolysis  of  the  neutral  salt  of  the  great  series  of  or- 
ganic acids  of  the  general  formula  C'E'^O*  has  thrown  great  light  on  some  previously  ob- 
scure points  in  the  radical  theory. 

The  decompositions  undergone  by  organic  substances  in  contact  with  reagents  are  so 
manifold,  that  the  limits  of  this  work  preclude  the  possibility  of  doing  more  than  glancing 
at  a  few  of  the  most  general  and  interesting.  Peihaps  of  all  the  modes  of  inducing  the 
breaking  up  of  more  complex  into  simpler  substances,  the  application  of  heat  is  the  most 
remarkable  for  its  power  and  the  varied  and  opposite  character  of  the  substances  produced. 
It  has  been  shown  that,  as  a  decomposing  agent,  heat  possesses  no  special  function.  From 
complex  organic  molecules  all  classes  of  substances  are  formed.  Individual  substances  be- 
longing to  every  chemical  type  are,  therefore,  found  among  products  of  destructive  distilla- 
tion. Acids,  alkalies,  and  neutral  bodies  of  every  kind  are  formed,  and  some  of  the  most 
interesting  and  beautiful  bodies  known  to  chemists  are  found  in  the  uninviting  looking  tar 
of  coal.  Let  us  illustrate  this  by  a  glance  at  a  few  of  the  coal-tar  products.  Among  the 
acids  are  the  oxyphenic,  carbolic,  and  crcsylic.  The  alkaloids  represented  are  methyla- 
mine,  ethylamine,  propylamine,  butylamine,  amylamine,  pyridine,  picoline,  lutidine,  colli- 
dine,  parvoline,  chinolinc,  Icpidine,  cryptidine,  and  aniline.  Among  hydrocar))ons,  ben- 
zole, toluole,  xylole,  cumole,  cymole,  propylc,  butyle,  amyle,  caproyle,  caproylene,  cenan- 
thylene,  napthaline,  anthracene,  chrysene,  pyrene,  &c.,  &c.  This  list,  probably,  does  not 
include  one-half  of  the  substances  produced  from  coal  by  the  decomposing  and  recomposing 
influence  of  heat. 

Mineral  acids  exercise  a  powerful  decomposing  influence  on  organic  substances.  Of 
these  the  nitric  and  sulphuric  are  the  most  commonly  used.  Nitric  acid  is  especially  active, 
owing  to  its  twofold  action.  By  virtue  of  its  oxidizing  tendencies,  it  breaks  up  great  num- 
bers of  substances  into  more  simple  and  less  carburetted  derivatives,  and  the  hyponitric  acid 
produced  by  the  removal  of  one  of  the  atoms  of  the  oxygen  of  the  acid  frequently  enters 
into  the  resulting  compound,  a  substitution  product  being  the  final  result.  In  the  latter 
bodies  produced  in  this  manner  the  hyponitric  acid  (NO'')  generally  replaces  hydrogen,  the 
original  type  remaining  unaltered.  The  production  of  oxalic  acid  from  sugar ;  succinic, 
lipic,  adipic,  pimelic,  suberic,  &c.,  acids  from  oily  and  fatty  matters  by  the  action  of  nitric 
acid,  are  examples  of  its  oxidizing  power ;  while  the  formation  of  nitrobenzole,  and  bodies 
of  more  or  less  analogous  character,  presents  instances  of  the  replacement  of  hydrogen  by 
hyponitric  acid. 

Sulphuric  acid  owes  its  decomposing  power  to  its  extreme  tendency  to  combine  with 
water.  Many  of  the  less  stable  organic  liodies  are,  by  this  means,  absolutely  broken  up, 
so  that  the  resulting  products  are  of  a  character  too  indefinite  to  allow  of  the  changes 
being  expressed  by  an  equation  which  shall  render  a  true  account  of  all  the  substances 
directly  or  indirectly  formed.  On  the  other  hand,  the  action  may  be  so  controlled  by  the 
careful  regulation  of  the  temperature  and  strength  of  the  acid  that  products  may  be  ehmi- 
nated  which  are  themselves  totally  lirokcn  up  and  destroyed  by  an  acid  of  greater  strength. 
The  production  of  grape  sugar  by  the  action  of  sulphuric  acid  on  starch,  or  lignine,  may  be 
taken  as  an  example.  It  not  unfrequeutly  happens,  that  the  sulphuric  acid  unites  with 
the  substance  acted  on  to  form  a  conjugated  compound.     Benzole,  and  many  other  hy- 


DESICCATION 


443 


drocart)ons,  as  well  as  oxidized  bodies,  behave  in  this  manner  with  concentrated  sulphuric 
acid. 

Chlorine  and  the  other  halogens  are  powerful  decomposing  agents,  acting  chiefly  by  vir- 
tue of  their  affinity  for  hydrogen.  The  principal  effects  produced  by  them  arc  oxidation 
and  substitution.  The  oxidizing  action  of  the  halogens  arises  from  the  decomposition  of 
water ;  the  hydrogen  combining  with  the  chlorine,  &c.,  to  form  an  hydracid,  and  the  free 
oxygen  uniting  with  the  other  substances  present. 

'  The  above  sketch  will  sufficiently  indicate  some  of  the  most  usual  methods  by  which 
the  decomposition  of  organic  and  inorganic  bodies  is  effected ;  but  hundreds  of  other  de- 
composing agencies  are  at  the  call  of  the  chemist,  when  any  phenomena  involving  the  dis- 
ruptions of  compounds  are  to  be  investigated. — C.  G.  W. 

DEODORIZERS.  Bodies  which  have  the  power  of  depriving  fetid  and  offensive  effluvia 
of  their  odors.  There  appears  to  exist  a  general  idea  that  these  substances  are,  all  of  them, 
equally  disinfectants.  No  greater  mistake  can  be  made  than  to  suppose  that  because  a  pre- 
paration has  the  power  of  removing  a  disagreeable  smell,  that  therefore  it  has  removed  all 
the  elements  of  infection  or  disease.     See  Disinfectant. 

To  disguise  unpleasant  odors,  fumigation  is  employed,  many  of  the  fragrant  gums  are 
burnt,  and  fumigating  pastilles  employed.  It  is  also  a  common  practice  to  burn  lavender 
and  brown  paper,  but  these  merely  overpower  or  disguise  the  smell ;  they  do  not  in  any 
way  act  upon  the  noxious  effluvia. 

DERRICK  CRANE.  The  term  Derrick  is  applied  to  a  temporary  crane,  consisting  of 
a  spar  supported  by  stays  and  guys,  carrying  a  purchase  for  loading  or  unloading  goods  on 
shipboard.  The  Derrick  crane  is  somewhat  similar  in  its  plan,  the  projecting  iron  beam  or 
derrick  of  which  can  be  raised  or  lowered  to  any  desired  angle. 

DESICCATION.     The  act  of  drying. 

Davison  and  Symington  patented  a  process  for  drying  or  seasoning  timber,  by  currents 
of  heated  air.  Even  after  wood  has  been  dried  in  the  ordinary  manner,  it  contains  much 
moisture,  which  it  is  still  necessary  to  remove.  The  patentees  have  given  some  curious  re- 
sults of  this  desiccating  process : — 

Temperature  of  air  214°. 


Yiolin  wood. 

Original 

weiglit. 

Weight  after 
seasoning. 

Moisture  removed. 

6  pieces  small  and  thin          ... 
2  pieces  larger      ..... 
2  pieces  larger      ..... 

3-38 
10-56 
25-25 

2-87 

9-5 

22-93 

8-     per  cent. 
10-1         do. 
9-25       do. 

Original 

weight. 

100° 

after 

6  hours. 

120' 

after 

10  hours. 

150° 

after 

20  hours. 

ISO" 

after 

30  hours. 

230° 

after 

38  hours. 

Per  cent. 

Oak       - 

1-84 

1-76 

1-71 

1-59 

1-56 

1-51 

18-1 

Red  pine 

1-5 

1-4 

1-38 

1-33 

1-28 

1-25 

16-0 

Birch    . 

1-2 

1-09 

1-05 

1-01 

•99 

•97 

19-2 

Mahogany 

1-21 

1-14 

1-09 

1-03 

1-0 

•98 

19-2 

Wliito 

vood,  lime  tree. 

Original 
weight. 

170° 
after  6  hours. 

Part  140°,  and 

part  212° 
after  15  hours. 

After 
2-1  hours. 

After 
84  hours. 

After 
84  hour.s.* 

Per  cent. 

1 

2 
3 

4 

23-5 
25-19 
23^67 
20-08 

20-45 
21-33 
19-7 
17-07 

18^7 
19-37 
17-83 
15-8 

18-22 
18-9 
*  17-6 
15-6 

17^4 

18^07 
16-82 
15-13 

17-4 
18^0 
16^75 
15-05 

20- 
28-5 
29-2 
26^ 

No.  3  exposed  to  the  atmosphere  for  three  weeks,  weighed  at  the  end  of  that  time  17^8, 
or  had  taken  in  4-2  per.  cent  of  moisture. 


*  It  will  be  observed,  on  referring  to  the  last  column  of  lime,  that  the  wood,  altliongli  kept  in  the 
chamber  exposed  to  heated  currents  for  50  hours,  weighed  notliing  less  after  the  tirst  34  hours. — (  W/i /'.■<- 
haw.)  One  application  of  the  de.sicealing  process  fortiinber  is  to  expose  it  for  .some  hours  to  the  heated 
currents  of  air,  and  then,  in  its  licated  state,  immersing  it  suddenly  in  any  of  the  approved  antiseptics, 
creosote  or  coal-tar.  Tlio  result  is,  that  the  air-ve.ssels  of  the  wood,  if  not  entirely  empty,  contain  air 
at  so  very  high  a  temperature  that  a  vaeiuiin  is  instantly  formed,  and  every  poro  is  iinmodlatuly  charged 
with  the  cold  antiseptic  in  which  tlio  wood  is  immersed. 


444  DEXTRINE. 

Feathers. — Feather  beds,  mattresses,  blankets,  and  clothing  are  not  only  dried,  but 
purified  by  this  process.  A  feather  bed  of  sixty  pounds'  weight,  will  have  no  less  than 
100,000  cubic  feet  of  air  passed  through  it ;  and  at  the  same  time  beaters  are  made  use  of, 
for  the  purpose  of  removing  the  dust.  Feathers  treated  in  this  manner  have  their  bulk  and 
elasticity  so  much  increased,  that  a  second  tick  is  found  almost  invariably  necessary  to  put 
the  feathers  into. 

A  practical  proof  of  the  extreme  powers  of  currents  of  dry  heated  air  was  given  in 
Syria,  by  exposing  to  them  sixty  suits  of  clothes,  which  had  belonged  to  persons  who  died 
of  the  plague.  These  clothes  were  subjected  to  the  process  alluded  to,  at  a  temperature  of 
about  240°,  and  afterwards  worn  by  sixty  living  persons,  not  one  of  whom  ever  gave  the 
slightest  symptoms  of  being  in  the  slightest  degree  affected  by  the  malady.  (  Whishaw.) 
The  purification  of  feathers  by  tliis  process  is  carried  out  in  many  large  establishments. 
Coffee  it  has  been  proposed  to  dry  by  currents  of  heated  air,  and  subsequently  to  roast  it 
by  the  same  process. 

2' flick  card-board,  used  for  tea-trays  and  papier  mache,  is  now  frequently  dried  by 
heated  air.  By  the  plan  adopted  at  one  establishment,  previously  to  the  introduction  of 
Davison  and  Symington's  method,  it  invariably  occupied  from  eighteen  to  twenty  hours  to 
dry  a  room  full  of  paper  by  a  heating  surface  equal  to  330  feet ;  whereas  by  the  new  method 
the  same  amount  of  work  is  accomplished  in  four  hours,  and  with  a  heating  surface  of  only 
46  feet,  or  one-seventh  the  area  required  by  the  former. 

Silk. — For  the  purpose  of  drying  silk,  it  has  been  usual  to  heat  the  drying  chambers  by 
large  cast-iron  globular  stoves;  the  heat  obtained  thus  was  equal  to  120°  F.,  but  excessively 
distressing  to  any  stranger  entering  these  apartments. 

In  one  arrangement  7,000  cubic  feet  per  minute  are  admitted  at  the  above  tempera- 
ture through  small  perforated  iron  plates,  let  into  the  stone  floor.  As  many  as  3,000 
pieces  of  silk  are  sometimes  suspended  at  one  time ;  and  as  each  piece  of  silk,  when 
wet,  contains  about  seven  ounces  of  water,  and  as  the  operation  of  drying  the  whole 
occupies  but  one  hour,  it  follows  that  about  130  gallons  of  water  are  evaporated  in  that 
time. 

Yarn/!. — In  Scotland  and  other  places  they  now  dry  yarns  l)y  modified  applications  of 
this  process  ;  and  it  is  indeed  extensively  used  in  lileaching  establisliments,  in  calico-print- 
ing works,  &c.     See  Trajisactions  of  the  Society  of  Arts  for  1847-'8. 

DEXTRINE.  Starch  Gum.  There  are  three  modes  of  obtaining  this  from  starch,  viz. : 
by  torrefaction,  by  the  action  of  dilute  acids,  and  by  the  action  of  diastase.  The  impure 
dextrine  obtained  by  roasting  is  termed  roasted  starch,  or  leicommc.  British  gum  is  pre- 
pared by  carefully  roasting  wheat  starch,  at  a  temperature  of  300°  Fahr.  Another  method 
of  preparing  dextrine  consists  in  moistening  1,000  parts  of  potato  starch  with  300  parts  of 
water,  to  which  two  parts  of  nitric  acid  have  been  added.  The  mixture  is  allowed  to  dry 
spontaneously,  and  is  afterwards  heated  for  two  or  three  hours  in  a  stove  at  212°  Fahr. 
Dextrine  in  many  of  its  characters  resembles  ordinary  gum,  but  it  is  distinguishable  from  it 
bv  its  riqht-handcd  rotation  of  a  ray  of  plane  polarized  liyht, — hence  its  name  dextrine, — 
and  liy  its  yielding  oxalic  acid,  but  not  mucic  acid,  when  heated  with  nitric  acid.  Its  chem- 
ical formula  is  C'-II»03,II0. 

DIA.MA(!XETISM.  As  this  term  is  becoming  more  generally  used  in  our  language,  it 
appears  necessary  to  give  a  definition  of  it,  although  it  is  not  our  purpose  to  enter  on  the 
consideration  of  any  purely  physical  subject. 

The  term  was  introduced  by  Dr.  Faraday  to  express  those  bodies  which  did  not  act  as 

magnetic  bodies  do.     If  n  and  s  represent  the  poles  of  a  horse-shoe 

215  magnet,  any  bar  of  a  magnetic  character,  as  iron,  cobalt,  or  nickel, 

;;c  hung  up  between  them  and  free  to  move,  will,  by  virtue  of  the  attract- 

;  \  ing  and  repelling  polar  forces,  place  itself  along  the  line  joining  the 

NO  ^       ' '         1  cs     two  poles  «  b,  which  is  called  the  magnetic  axis.     If  instead  of  a  bar 

I  i  of  iron  we  suspend  in  the  same  manner  a  rod  of  glass,  of  bismuth,  or 

[i^  of  silver,  it  will  arrange  itself  equatorially,  or  across  the  line  a  b,  as 

shown  by  the  dotted  line  c  d.     AH  bodies  in  nature   appear  to  exist 

in  one  of  those  two  conditions.     The  prefix  dia  is  used  here  in  the  same  sense  as  in 

dia-meter.     See  De  La  Hire's  Electricity,  fou  a  full  explanation  of  all  the  dianiagnetic 

phenomena. 

DIAMOND.  {Diamant,  Fr.  ;  I)ia7nant,  Germ.)  Experiment  has  determined  that  this 
beautiful  gem  is  a  peculiar  (allotropic)  condition  of  carbon.  By  burning  the  diamond  in 
oxygen  gas  we  produce  carbonic  acid  ;  and  by  enclosing  the  gem  in  a  mass  of  iron,  and 
suljecting  it  to  a  strong  heat,  the  metal  is  converted  into  steel,  when  the  diamond  has  dis- 
appeared. It  has  been  shown  tliat  we  can,  by  the  agency  of  the  heat  of  the  voltaic  arc, 
convert  tlie  diamond  into  excellent  coke,  and  into  graphite;  but  although  portions  of  coke 
arc  found  to  be  sufficiently  hard  to  cut  glass,  we  have  not  yet  succeeded  in  making  dia- 
monds from  coke.  Sir  Humphry  Davy  noticed  that  the  charcoal  of  one  of  the  poles  of 
Mr.  Children's  great  voltaic  battery  was  considerably  hardened,  and  he  regarded  this  as  an 


DIAMOND. 


445 


advance  towards  the  production  of  that  gem.  Recently  some  experiments  made  by  a  French 
philosopher  have  advanced  the  discovery  another  step  :  one  of  the  poles  of  a  voltaic  battery 
being  charcoal  and  the  other  of  platinum,  it  was  found  that  the  tine  charcoal  escaping  from 
the  carbon  pole  and  depositing  itself  on  the  platinum  pole  was  sufficiently  hard  to  be 
used  in  the  place  of  diamond  dust  for  polishing  gems.  The  formation  of  the  diamond 
in  nature  is  one  of  the  problems  which  "our  philosophy"  has  not  yet  enabled  us  to  solve. 
Time  is  an  element  which  enters  largely  into  nature's  works ;  she  occupies  a  thousand,  or 
even  thousands  of  years,  to  produce  a  result,  while  man  in  his  experiments  is  confined  to  a 
few  days,  or  a  few  years  at  most. 

The  following  remarks  by  Mr.  Tennant  cannot  fail  to  be  of  interest,  and,  as  pointing 
out  the  errors  which  have  been  frequently  committed  through  ignorance,  of  great  value. 

"  By  attending  to  the  forms  of  the  crystal,  we  are  quite  sure  that  we  shall  not  find  the 
emerald,  sapphire,  zircon,  or  topaz,  in  the  form  of  a  cube,  octahedron,  tetrahedron,  or 
rhombic  dodecahedron  ;  nor  the  diamond,  spinel,  or  garnet,  in  that  of  a  six-sided  prism, 
and  so  on  with  other  gems.  For  want  of  a  knowledge  of  the  crystalline  form  of  the  dia- 
mond, a  gentleman  in  Caliibrnia  offered  £200  for  a  small  specimen  of  quartz.  He  knew 
nothing  of  the  substance,  except  that  it  was  a  bright  shining  mineral,  excessively  hard,  not 
to  be  scratched  by  the  file,  and  which  would  scratch  glass.  Presuming  that  these  qualities 
belonged  only  to  the  diamond,  he  conceived  that  he  was  offering  a  fair  price  for  the  gem  ; 
but  the  owner  declined  the  offer.  Had  he  known  that  the  diamond  was  never  found  as  a 
six-sided  prism,  terminated  at  each  end  by  a  six-sided  pyramid,  he  would  have  been  able  to 
detect  the  fact  that  what  he  was  offered  £200  for,  was  really  not  worth  more  than  half  a 
crown." — Tennant's  Lecture  on  Gems. 

The  accompanying  forms  may  serve  to  guide  those  who  are  ignorant  of  crystallography. 


218    Brilliant,  (upper  side.) 


219    Eose. 


Quartz. 


100 
carets. 


o 

</,  table;  6,  star-facets;  c,  skill -facets;  (f,  lozenges;  f,  girdle. 

The  following  technical  terms  are  applied  to  the  different  faces  of  diamonds : — 

Bezils  :  the  upper  sides  and  corners  of  the  brilliant,  lying  between  the  edge  of  the  table 
and  the  girdle. 

Collet :  the  small  horizontal  plane  or  face,  at  the  bottom  of  the  brilliant. 

Crown :  the  upper  work  of  the  rose,  which  all  centres  in  the  point  at  the  top,  and  is 
bounded  by  the  horizontal  ribs. 

Facets :  small  triangular  fiices,  or  planes,  both  in  brilliants  and  roses.  In  brilliants 
there  are  two  sorts,  skew  or  s^-iW-faccts,  and  s<«r-facets.  Skill-facets  are  divided  into  vpper 
and  imder.  Upper  skill-facets  are  wrought  on  the  lower  part  of  the  bezil,  and  terminate  in 
the  girdle  ;  under  skill-facets  are  wrought  on  the  pavilions,  and  terminate  in  the  girdle ; 
star-facets  are  wrought  on  the  upper  part  of  the  bezil,  and  terminate  in  the  table. 

Girdle :  the  line  which  encompasses  the  stone  parallel  to  the  horizon  ;  or,  which  deter- 
mines the  greatest  horizontal  expansion  of  the  stone. 

Lozenges  :  are  common  to  brilliants  and  roues.  In  brilliants  they  are  formed  by  tlie 
meeting  of  the  skill  and  star-facets  on  the  bezil.  In  roses,  by  the  meeting  of  tlie  facets  in 
the  horizontal  ribs  of  the  crown. 

Pavilions  :  the  under  sides  and  corners  of  brilliants,  lying  between  the  girdle  and  the 
collet. 

Ribs :  the  lines,  or  ridges,  which  distinguish  the  several  parts  of  the  work,  both  in 
brilliants  and  roses. 

Table  :  the  large  horizontal  plane,  or  fiice,  at  the  top  of  the  brilliant. 
-Fig.  218  represents  a  brilliant,  and  fig.  219  a  rose-cut  diamond. 

The  rose  diamond  is  flat  beneath,  like  all  weak  stones,  while  the  upper  flice  rises  into  a 
dome  and  is  cut  into  facets.  Most  usually  six  facets  are  put  on  the  central  region,  which 
are  in  the  form  of  triangles,  and  unite  at  their  sunnnits  ;  their  bases  abut  upon  another 
range  of  triangles,  which  being  set  in  an  inverse  position  to  the  jnrceding,  present  their 
bases  to  them,  while  their  summits  terminate  at  the  sharp  margin  of  the  stone.     The  latter 


446  DIAMOND  CUTTING. 

triaiiEflcs  leave  spaces  between  them  which  are  likewise  cut  each  into  two  facets.  By  this 
distribution  the  rose  diamond  is  cut  into  24  facets ;  the  surface  of  the  diamond  being 
divided  into  two  portions,  of  which  the  upper  is  called  the  crown,  and  that  forming  the  con- 
tour, beneath  the  ibrmer,  is  called  daitellc  (lace)  by  the  French  artists. 

According  to  Mr.  Jefferies,  in  his  Treatise  on  Diamonds,  the  regular  rose  diamond  is 
formed  by  inscribing  a  regular  octagon  in  the  centre  of  the  table  side  of  the  stone,  and  bor- 
dering it  by  eight  right-angled  triangles,  the  bases  of  which  correspond  with  the  sides  of 
the  octagon  ;  beyond  these  is  a  chain  of  8  trapeziums,  and  another  of  l(j  triangles.  The 
collet  side  also  consists  of  a  minute  central  octagon,  irom  every  angle  of  which  proceeds  a 
ray  to  the  edge  of  the  girdle,  forming  the  whole  surface  into  8  trapeziums,  each  of  which 
is  again  subdivided  by  a  salient  angle  (whose  apex  touches  the  girdle)  into  one  irregular 
pentagon  and  two  triangles. 

To  fashion  a  rough  diamond  into  a  brilliant,  the  first  step  is  to  modify  the  faces  of  the 
original  octahedron,  so  that  the  plane  formed  by  the  junction  of  the  two  pyramids  shall  be 
an  exact  square,  and  the  axis  of  the  crystal  precisely  twice  the  length  of  one  of  the  sides 
of  the  square.  The  octahedron  being  thus  rectified,  a  section  is  to  be  made  parallel  to  the 
common  base  or  f/irdlc,  so  as  to  cut  off  5-eighteenths  of  the  whole  height  from  the  upper 
pyramid,  and  1-cighteenth  from  the  lower  one.  The  superior  and  larger  plane  thus  pro- 
duced is  called  the  tabic,  and  the  inferior  and  smaller  one  is  called  the  colUt ;  in  this  state 
it  is  termed  a  complete  square  tabic  diamond.  To  convert  it  into  a  brilliant,  two  triangular 
facets  are  placed  on  each  side  of  the  table,  thus  changing  it  from  a  square  to  an  octagon  ; 
a  lozenge-.shaped  facet  is  also  placed  at  each  of  the  four  corners  of  the  table,  and  another 
lozenge  extending  lengthwise  along  the  whole  of  each  side  of  the  original  square  of  the 
table,  which,  with  two  triangular  facets  set  on  the  base  of  each  lozenge,  conjpletes  the 
whole  number  of  facets  on  the  table  side  of  the  diamond  ;  viz.,  8  lozenges,  and  24  triangles. 
On  the  collet  side  arc  formed  4  irregular  pentagons,  alternating  with  as  many  irregular 
lozenges  radiating  from  the  collet  as  a  centre,  and  bordered  by  IC  triangular  facets  adjoin- 
ing the  girdle.  The  brilliant  being  thus  completed,  is  set  with  the  table  side  uppemiost, 
and  the  collet  side  implanted  in  the  cavity  made  to  receive  the  diamond.  The  brilliant  is 
always  three  times  as  thick  as  the  rose  diamond.  In  France,  the  thickness  of  the  brilliant 
is  set  off  into  two  unequal  portions;  one-third  is  reserved  for  the  upper  part  or  table  of  tlie 
diamond,  and  the  remaining  two-thirds  for  the  lower  part  or  collet,  {culassc.)  The  table  has 
eight  planes,  and  its  circumference  is  cut  into  facets,  of  which  some  are  triangles  and  others 
lozenges.  The  collet  is  also  cut  into  facets  called  2tarillo7is.  It  is  of  consequence  that  the 
pavilions  lie  in  the  same  order  as  the  upper  facets,  and  that  they  correspond  to  each  other, 
so  that  the  symmetry  be  perfect,  for  otherwise  the  play  of  the  light  would  be  false. 

Although  the  rose  diamond  projects  bright  beams  of  light  in  more  extensive  proportion 
often  than  the  brilliant,  yet  the  latter  shows  an  incomparably  greater  play,  from  the  difler- 
enee  of  its  cutting.  In  executing  this,  there  are  formed  32  faces  of  dificrent  figures,  and 
inclined  at  different  angles  all  round  the  table,  on  the  upper  side  of  the  stone.  On  the  col- 
let (culasse)  24  other  faces  are  made  round  a  small  table,  which  converts  the  culasse  into  a 
truncated  pyramid.  These  24  facets,  like  the  32  aljove,  are  differently  inclined,  and  present 
different  figures.  It  is  essential  that  the  faces  of  the  top  and  the  bottom  correspond  to- 
gether in  sufficiently  exact  proportions  to  nmltiply  the  reflections  and  refractions,  so  as  to 
produce  the  colors  of  the  prismatic  spectrum. 

DIAMOND  CUTTING.  The  following  description,  furnished  to  Mr.  Tennant  by  Messrs. 
Garrard,  of  the  cutting  of  the  K(jh-l-noor,  will  fully  explain  the  peculiar  conditions  of  the 
process,  and  also  show  that  there  are  some  rcmaikable  differences  in  the  physical  condition 
of  the  gem  in  its  different  jilanes.  The  letters  refer  to  the  cut  of  the  Koh-i-noor,  article 
Diamond,  fir/.  220. 

"  In  cutting  diamonds  from  the  rough,  the  process  is  so  uncertain  that  the  cutters  think 
themselves  fortunate  in  retaining  one-half  the  original  weight.  The  Koh-i-noor,  on  its 
an-ival  in  England,  was  merely  surface-cut,  no  attempt  having  been  made  to  produce  the 
regular  form  of  a  brilliant,  by  which  ahme  lustre  is  obtained.  By  reference  to  the  figures, 
which  are  the  exact  size  of  the  Koh  i-noor,  it  will  be  clearly  understood  that  it  was  neces- 
sary to  remove  a  large  portion  of  the  stone  in  order  to  obtain  the  desired  effect,  by  which 
means  the  apparent  surface  was  increased  rather  than  diminished,  and  the  flaws  and  yellow 
tinge  were  removed. 

"  The  process  of  diamond  cutting  is  effected  l)y  an  horizontal  iron  plate  of  about  ten 
inches  diameter,  called  a  ■fcbi/f,  or  miJl,  which  revolves  from  two  thousand  to  three  thou- 
sand times  ]>er  minute.  The  diamond  is  fixed  in  a  ball  of  pewter  at  the  end  of  an  arm, 
resting  upon  the  talile  in  which  the  plate  revolves;  the  other  end,  at  which  the  ball  con- 
taining the  diamond  is  fixed,  is  pressed  upon  the  wheel  by  movable  weights  at  the  discretion 
of  the  workmen.  The  weight  applied  varies  from  2  to  30  lbs.,  according  to  the  size  of  tlie 
facets  intended  to  be  cut.  The  rccutting  of  the  Koh-i-noor  was  commenced  on  July  10, 
1852,  His  Grace  the  late  Duke  of  Wellington  being  the  first  person  to  place  it  on  the  mill. 
The  portion  first  worked  upon  w;u}  that  at  which  the  planes  p  and  F  meet,  as  it  was  ncccs- 


DIPPING.  447 

sary  to  reduce  the  stone  at  that  part,  and  so  to  level  the  set  of  the  stone  before  the  table 
could  be  formed ;  the  intention  being  to  turn  the  stone  rather  on  one  side,  and  take  the 
incision  or  flaw  at  r.,  axid  a  fracture  on  the  other  side  of  the  stone,  not  shown  in  the  engrav- 
ing,  as   the  boundaries  or  sides  of  the  girdle. 

Tlie  next   important   step   was   the    attempt   to  •j.-2  > 

remove  an  incision  or  flaw  at  C,  described  by 
Professor  Tennant  and  the  Kev.  W.  Mitchell 
as  having  been  made  for  the  purpose  of  hold- 
ing the  stone  more  firmly  in  its  setting,  but 
jironounccd  by  the  cutters  (after  having  cut 
into  and  examined  it)  to  be  a  natural  flaw  of  a 
yellow  tinge,  a  defect  often  met  with  in  small 
stones.  The  next  step  was  cutting  a  facet  on 
tlie  top  of  the  stone  immediately  above  the 
last-mentioned  flaw.  Here  the  difl'erence  in  the 
hardness  of  the  stone  first  manifested  itself;  for  while  cutting  this  facet,  the  hspidary  notic- 
ing that  the  work  did  not  proceed  so  fast  as  hitherto,  allowed  the  diamond  to  remain  on  the 
mill  rather  longer  than  usual,  without  taking  it  off  to  cool ;  the  consequence  was,  tliat  the 
diamond  became  so  hot  from  the  continual  friction  and  greater  weight  applied,  that  it 
melted  the  pewter  in  which  it  was  imbedded.  Again,  while  cutting  the  same  facet,  the  mill 
became  so  hot  from  the  extreme  hardness  of  the  stone,  that  particles  of  iron  mixed  with 
diamond  powder  and  oil  ignited.  The  probable  cause  of  the  diamond  proving  so  hard  at 
this  part  is,  that  the  lapidary  was  obliged  to  cut  directly  upon  tlie  angle  at  which  two  cleav- 
age planes  meet,  cutting  across  the  grain  of  the  stone.  Another  step  that  was  thus  consid- 
ered to  be  important  by  the  cutters,  was  removing  a  flaw  at  g.  This  flaw  was  not  thought 
by  Professor  Tennant  and  Mr.  Mitchell  to  be  dangerous,  because  if  it  were  allowed  to  run 
according  to  the  cleavage,  it  would  only  take  olF  a  small  piece,  which  it  was  necessary  to 
remove  in  order  to  acquire  the  present  shape.  The  cutters,  however,  had  an  idea  that  it 
might  not  take  the  desired  direction,  and,  therefore,  began  to  cut  into  it  from  both  sides, 
and  afterwards  directly  upon  it,  and  thus  they  succeeded  in  getting  rid  of  it.  While  cut- 
ting, the  stone  appeared  to  become  harder  and  harder  the  further  it  was  cut  into,  especially 
just  above  the  flaw  at  a,  v.'hich  part  became  so  hard,  that,  after  working  the  mill  at  the  medium 
rate  of  2,4(10  times  per  minute,  for  six  hours,  little  impression  had  been  made  ;  the  speed 
was  therefore  increased  to  more  than  3,000,  at  which  rate  the  work  gradually  proceeded. 
When  the  back  (or  former  top)  of  the  stone  was  cut,  it  proved  to  be  much  softer,  so  that  a 
facet  was  made  in  three  hours,  which  would  have  occupied  more  than  a  day,  if  the  hardness 
had  been  equal  to  that  on  the  other  side  ;  nevertheless,  the  stone  afterwards  became  gradu- 
ally harder,  especially  underneath  the  flaw  at  a,  which  part  was  nearly  as  hard  as  that 
directly  above  it.  The  flaw  at  n  did  not  interfere  at  all  with  the  cutting.  An  attempt  was 
made  to  cut  out  the  flaw  at  a,  but  it  was  found  not  desirable  on  account  of  its  length.  The 
diamond  was  finished  on  September  Tth,  having  taken  thirty-eight  days  to  cut,  working 
twelve  hours  per  day  without  cessation."  The  weight  of  the  Koh-i-noor  since  cutting  is 
102^  carats. 

DIAMOND  TOOLS.  1.  The  Glazier's  Diamond  is  the  natural  diamond,  so  set  that 
one  of  its  edges  is  brought  to  bear  on  the  glass. 

The  extreme  point  of  any  diamond  will  scratch  glass,  making  a  white  streak  ;  but  when 
tlie  rounded  edge  of  a  diamond  is  slid  over  a  sheet  of  glass  with  but  slight  pressure,  it  pro- 
duces a  cut,  which  is  scarcely  visible,  but  which  readily  extends  through  the  mass. 

Dr.  Wollaston  succeeded  in  giving  to  the  ruliy,  topaz,  and  rock  crystal,  forms  similar  to 
those  of  the  diamond,  and  with  those  he  succeeded  in  cuit.inr/  glass ;  proving  that  tliis  use- 
ful property  of  the  diamond  depended  on  its  form.  Although  the  primitive  form  of  the 
diamond  is  that  of  a  regular  octahedron,  the  Duke  de  Bournon  has  published  upwards  of 
one  hundred  forms  of  crystallization  of  the  diamond.  The  irregular  octahedrons  with 
round  facets  are  those  proper  for  glaziers'  diamonds. 

Notwithstanding  the  hardness  of  the  diamond,  j-et,  in  large  glass  works,  as  many  as  one 
and  two  dozens  are  worn  out  every  week  :  from  being  convex,  they  become  rapidly  con- 
cave, and  the  cutting  power  is  lost. 

2.   Diamond  Brills  are  made  of  various  shapes ;  these  are  either  found  amongst  imper- 
fect diamonds,  or  are  selected  from  fragments  split  off  from  good  stones  in  their  manufac- 
ture for  jewelling. 
•     DIES,  hardening  of.     See  Steet,,  hardening  of,  vol.  ii. 

DIPPIX(}.  Ornamental  works  in  Ijrass  are  usually  brightened  by  a  process  called  dip- 
pinrj.  After  the  work  has  been  properly  fitted  together  and  the  grease  removed,  either  by 
the  action  of  heat,  or  by  boiling  in  a  pearl  ash  lye,  it  is  pickled  in  a  bath  of  dilute  aqua 
fortis.  It  is  then  scoured  bright  with  sand  and  water,  and  being  well  washed  is  plunged 
into  the  dipping  bath,  which  consists  of  pure  nitrous  acid,  commonly  known  as  dipping 
aquafortis,  for  an  instant  oidy,  and  is  then  well  washed  with  cold  and  hot  water  to  remove 


448  DISINFECTANT. 

every  trace  of  acid  from  the  surface,  after  which  the  work  is  put  into  dry  beech  or  box 
wood,  sawdust,  &c.,  well  rubbed  uutil  it  is  quite  dry,  and  then  burnished  and  lackered  with 
as  little  delay  as  possible. 

DISINFECTANT.  A  substance  which  removes  the  putrid  or  infected  condition  of 
bodies.  It  is  well  not  to  confound  it  with  antiseptic,  which  applies  to  those  bodies  which 
prevent  putrefaction.  The  word  disinfectant  has  lately  become  somewhat  uncertain  in  its 
moaning,  on  account  of  a  word  being  used  as  its  equivalent,  viz.,  deodorizer.  This  latter 
means  a  substance  which  removes  odors.  In  reality,  however,  there  are  no  such  substances 
known  to  us  as  a  class.  There  are,  of  course,  some  substances  which  dcstroj'  certain  others 
having  an  odor,  but  in  all  cases  the  removal  of  the  smell  and  the  destruction  or  neutraliza- 
tion of  the  body  must  be  simultaneous.  There  is,  however,  a  large  class  of  substances 
that  destroy  putrefaction,  and  the  name  disinfectant  is  therefore  distinctly  needed.  The 
gases  which  rise  from  putrefying  bodies  are  not  all  capable  of  being  perceived  by  the 
senses  in  their  ordinary  condition ;  but  sometimes  they  are  perceived.  A  disinfectant  puts 
a  stop  to  them  and  deodorizes  simultaneously.  If  any  substance  were  to  remove  the  smell 
of  these  gases,  it  would  remove  the  gases  too,  as  they  are  inseparable  from  their  property 
of  affecting  the  nose.  A  deodorizer  would  therefore  be,  and  is,  a  disinfectant  of  that  gas 
the  smell  of  which  it  removes.  But  it  has  been  suggested  that  it  may  remove  those  gases 
which  smell,  and  allow  the  most  deleterious  to  pass,  they  having  no  smell.  Whenever  we 
find  such  a  class  of  substances,  it  will  be  well  to  give  them  the  name  of  deodorizers. 
There  may  be  some  truth  in  the  hypothesis  that  metallic  salts  remove  the  sulphur,  and  by 
preventing  the  escape  of  sulphuretted  hydrogen  c.ause  less  odor,  without  complete  disinfec- 
tion. But  it  appears  that  the  decomposition  is  a  prevention  of  putrefaction  in  proportion 
to  the  removal  of  that  gas  in  cases  where  it  is  given  out,  and  it  is  quite  certain  that  me- 
tallic solutions  have  disinfecting  properties.  Any  solution  having  the  effect  here  supposed 
would  at  the  least  be  a  partial  disinfectant,  inasmuch  as  the  decomposition  would  be  so  far 
put  a  stop  to,  as  to  prevent  at  least  one  obnoxious  gas.  How  the  others  could  remain  un- 
acted on  in  this  case  it  is  difficult  to  comprehend.  To  prevent  the  foi-mation  of  one  gas  is 
to  arrest  decomposition  or  to  alter  the  whole  character  of  the  change  which  is  producing 
the  gases.  The  most  deleterious  of  emanations  have  no  smell  at  all  to  the  ordinary  senses, 
and  we  can  only  judge  of  the  evil  by  its  results,  or  the  fact  that  the  substances  capable  of 
producing  it  are  near,  or  by  the  analysis  of  the  air.  (See  Sanitary  Akraxgemknts.)  The 
cases  where  sulphuretted  hydrogen  accompanies  the  offensive  matter,  are  chiefly  connected 
with  faecal  decomposition.  This  gas  is  a  useful  indication  of  the  presence  of  other  sub- 
stances. So  far  as  is  known,  the  destruction  of  the  one  causes  the  destruction  of  the  other. 
But  the  presence  of  sulphuretted  hydrogen  is  no  proof  of  the  presence  of  infectious  mat- 
ter, nor  is  its  absence  a  proof  of  the  absence  of  infectious  matter,  it  being  only  an  occa- 
sional accompaniment.  When  the  infectious  matter  and  the  odoriferous  matter  are  one, 
as  in  the  case,  as  far  as  we  know,  of  putrid  flesh,  &c.,  then  to  deodorize  is  to  disinfect. 
We  can  find  then  no  line  of  duty  to  be  performed  by  deodorizers,  and  no  class  of  bodies 
that  can  bear  the  name,  although  there  may  be  a  few  cases  where  the  word  may  be  found 
convenient.  If,  for  example,  we  destroy  one  smell  by  superadding  a  greater,  that  might  in 
one  sense  be  a  deodorizing.  If  we  added  an  acid  metallic  salt,  and  removed  the  sulphu- 
retted hydrogen,  letting  loose  those  organic  vapors  which  for  a  while  accompany  this  act, 
we  might,  to  those  who  were  not  very  near,  completely  destroy  smell,  and  still  send  a  sub- 
stance into  the  air  by  no  means  wholesome  ;  but  in  such  a  case  decomposition  is  stopped, 
at  least  for  a  while.  The  smelling  stage  is  by  no  means  the  most  dangerous,  nor  has  the 
use  of  the  word  deodorize  any  relation  to  sanitary  matters,  except  in  the  grossest  sense ;  it 
is  desiralile  that  persons  should  look  far  beyond  the  mere  indications  furnished  by  the  nose, 
and  as  in  science  we  can  find  no  deodorizers,  so  in  practice  we  need  not  look  for  any  in  the 
sense  usually  given  to  the  word.  The  word  may  be  used  for  such  substances  as  remove 
the  odor  and  the  putrefaction  of  the  moment,  but  allow  them  to  begin  again.  Even  in 
this  case  deodorizers  become  temporary  disinfectants,  which  character  all  removers  of  smell 
must  more  or  less  have. 

Antincpticx,  or  Colytic  Arjcnts.  Substances  which  prevent  decomposition.  The  words 
coli/.sis  and  coh/tic  come  from  KwXveo,  to  arrest,  ^rslrain,  cut  short.  This  word  was  pro- 
posed by  the  writer  to  apply  to  cases  such  as  are  included  under  antiseptics,  antiferments, 
and  similar  word.s.  There  was  needed  a  word  for  the  general  idea.  A  colytic  force  mani- 
fests itself  towards  living  persons  in  anjcsthetics,  anodynes,  and  narcotics,  as  well,  probably, 
as  in  other  ways.  Colytics  may  probably  act  from  diflcrcnt  causes,  but  these  causes  not 
being  separately  distinguished,  a  name  for  the  whole  class  can  alone  be  given.  The  actioti 
of  coll/sin  is  entirely  opposed  to  catalysis,  which  is  a  loosening  up  of  a  compound.  Colysis 
arrests  catalyxis,  as  well  also  as  other  processes  of  decomposition,  ordinary  oxidation  for 
example.  Disinfectants,  in  their  character  of  restraining  further  decomposition,  are  in- 
cluded under  colyticn.  One  of  the  most  remarkable  substances  for  arresting  decomposition 
is  krea.sotc.  It  has  Ijcen  used  in  some  condition  or  mixture  from  the  earliest  times.  The 
ancient  oil  of  cedar  has  been  called  Avith  good  reason  turpentine,  which  has  strong  disin- 


DISIKFECTANT. 


WJ 


fecting  properties ;  but  the  word  has  evidently  been  used  in  many  senses,  as  there  are 
many  liquids  to  be  obtained  from  cedar.  It  is  used  for  the  first  liquid  from  the  distillation 
of  wood ;  and  Berzelius  for  that  reason  says  that  the  Egyptians  used  the  pyroligneous  acid, 
which,  containing  some  kreasote,  was  a  great  antiseptic.  But  a  mixture  of  this  acid  with 
soda  would  be  of  little  value  in  embalming,  nor  is  it  probable  that  they  would  add  a  vola- 
tile liquid  like  turpentine  along  with  caustic  soda.  It  is  expressly  said  (in  Pliny)  that  the 
pitch  was  reboiled,  or,  in  other  word.-^,  the  tar  was  boiled  and  distilled,  the  product  being 
collected  in  the  wool  of  fleeces,  from  which  again  it  was  removed  by  pressure.  In  doing 
this  the  light  oils  or  naphtha  would  be  evaporated,  and  the  heavy  oil  of  tar,  containing  the 
carbolic  acid,  or  kreasote,  would  remain.  It  was  called  picenum,  as  if  made  of  pitch  or 
pissenum,  and  pisselajum  or  pitch  oil,  a  more  appropriate  name  than  that  of  Runge's  car- 
bolic acid  or  coal-oil,  and  still  more  appropriate  than  the  most  recent,  which,  by  following 
up  a  theory,  has  converted  it  into  phenic  acid.  The  distillation  was  made  in  copper  vessels, 
and  must  have  been  carried  very  far,  as  they  obtained  "a  reddish  pitch,  very  clammy,  and 
much  fatter  than  other  pitch."  This  was  the  anthracene,  chryscne,  and  pyrcne  of  modern 
chemistry.  The  remaining  hard  pitch  was  called  paliinpissa,  or  second  pitch,  which  we 
call  pitch  in  contradistinction  to  tar.  By  the  second  pitch,  however,  was  sometimes  meant 
the  product  of  distillation  instead  of  what  was  left  in  the  still.  Some  confusion  therefore 
exists  in  the  names,  but  not  more  than  with  us.  The  pitch  oil  was  resinous  fat,  and  of 
yellow  color,  according  to  some.  This  oil,  containing  kreasote,  was  used  for  toothache — a 
colytic  action  applied  to  living  bodies — and  for  skin  diseases  of  cattle,  for  which  it  is  found 
valuable.  They  also  used  it  for  preserving  hams. — {^''  Dishifectants"  by  t/ie  Writer.  Jour. 
Soc.  of  Arts,  1857.) 

It  is  quite  possible  that  kreasote  may  be  the  chief  agent  in  most  empyreumatic  sub- 
stances which  act  as  antiseptics.  But  it  is  not  the  only  agent.  Hydrocarbons  of  various  kinds 
act  as  antiseptics,  as  well  as  alcohol  and  methylic  alcohol,  which  contain  little  oxygen.  To 
this  class  belong  essential  oils  and  substances  termed  perfumes  which  are  used  for  fumiga- 
tion, and  have  also  a  powerful  colytic  action.  It  is  exceedingly  probable  that  the  true  the- 
ory of  this  action  is  connected  with  the  want  of  oxygen.  These  substances  do  not  rapidly 
oxidize,  but,  on  the  contrary,  only  very  slowly,  and  that  chiefly  by  the  aid  of  other  bodies. 
Their  atoms  are,  therefore,  in  a  state  of  tension,  ready  to  unite  when  assisted.  As  an  ex- 
ample, carbolic  acid  and  kreasote  unite  with  oxygen  when  a  base  is  present,  and  form 
rosolic  acid.  We  can  scarcely  suppose  that  an  explanation,  commonly  resorted  to  in  the 
case  of  sulphurous  acid,  would  suit  them  ;  viz.,  that  it  takes  up  the  oxygen,  and  so  keeps 
it  from  the  putrescible  substance.  It  is,  therefore,  much  more  likely  that  its  condition  acts 
on  the  putrescible  body.  For,  as  the  state  of  motion  of  a  putrefying  substance  is  trans- 
ferred to  another,  so  is  the  state  of  immobility. 

An  antiseptic  preserves  from  putrefaction,  but  does  not  necessarily  remove  the  odor 
caused  by  that  which  has  previously  putrefied.  Many  of  the  substances  described  as  disin- 
fectants here,  might  equally  be  called  antiseptics.  When  they  remove  the  putrid  matter, 
they  are  disinfectants  ;  when  they  prevent  decomposition,  they  are  antiseptics.  But  when 
the  smell  is  removed  by  a  substance  which  is  known  to  destroy  putrefactive  decomposition, 
and  to  preserve  organic  matter  entire,  then  we  have  the  most  thorough  disinfection ;  then 
we  know  that  the  removal  of  the  smell  is  merely  an  indication  of  the  removal  of  the  evil. 

Disinfectants  are  of  various  kinds.  Nature  seems  to  use  soil  as  one  of  the  most  active. 
All  the  dejecta  of  tlie  animals  on  the  surface  of  the  earth  fall  on  the  soil,  and  are  rapidly 
made  perfectly  innoxious.  Absorption  distinguishes  porous  bodies,  and  the  soil  has  peculiar 
facilities  for  the  purpose.  But  if  saturated,  it  could  disinfect  no  longer.  This  is  not  allowed 
to  occur ;  the  soil  absorbs  air  also,  and  oxidizes  the  organic  matter  which  it  has  received 
into  its  pores,  and  the  offensive  matter  is  by  this  means  either  converted  into  food  for  plant;;, 
or  is  made  an  innocent  ingredient  of  the  air,  or,  if  the  weather  be  moist,  of  the  water.  The 
air  is  therefore,  in  conjunction  with  the  soil,  one  of  the  greatest  disinfectants,  but  it  acts 
also  quite  alone  and  independent  of  the  soil.  Its  power  of  oxidizing  must  be  very  great. 
The  amount  of  organic  effluvium  sent  into  large  towns  is  remarkal)le,  and  yet  it  seldom 
accumulates  so  as  to  be  strongly  perceptible  to  the  senses.  The  air  oxidizes  it  almost  as 
rapidly  as  it  rises ;  this  is  hastened  apparently  by  the  peculiar  agent  in  the  air,  ozone,  wliich 
luis  a  greater  capacity  of  oxidation  than  the  common  air ;  when  this  is  exhausted  it  is  liighly 
probable  that  the  oxidation  will  be  much  slower,  and  this  exhaustion  does  take  place  in  a 
very  short  time.  So  rapid  is  the  oxidation,  that  the  wind,  even  lilowing  at  the  rate  of  about 
fifteen  to  twenty  miles  an  hour,  is  entirely  deprived  of  its  ozone  l)y  passing  over  less  than 
a  mile  of  Manchester.  In  London  tins  does  not  take  place  s^  rapidly,  at  least  near  the 
Thames.  But  when  the  ozone  is  removed,  it  is  prol)al)le  that  the  rate  of  increase  of  tlie 
organic  matter  will  be  much  greater.  We  nuiy  by  this  means,  then,  readily  gauge  the  con- 
dition of  a  town  up  to  a  certain  point  by  the  removal  of  the  ozone  :  but  it  rccjuires  another 
agent  to  gauge  it  afterwards  or  thoroughly.  It  is  in  connection  with  each  other  that  the  air 
and  the  soil  best  disinfect.  When  manure  is  thrown  upon  land  without  mixing  with  the 
soil,  it  may  require  a  very  long  period  to  obtain  thorough  disinfection,  but  when  the  atmos- 
VoL.  III.— 29 


450 


DISINFECTANT. 


phere  is  moist,  or  rain  falls,  then  the  air  is  rapidly  transferred  into  every  portion  of  the 
porous  earth,  and  the  organic  matter  becomes  rapidly  oxidized.  To  prevent  a  smell  of  ma- 
nure, and  with  it  also  the  loss  of  ammonia,  it  is  then  needful  that  as  soon  as  possible  the 
manure  should  be  mixed  with  the  soil.  The  same  power  of  oxidation  is  common  to  all 
porous  bodies,  to  charcoal,  and  especially,  as  Dr.  Stenhouse  has  shown,  to  platinized  char- 
coal. Disinfection  by  the  use  of  porous  bodies  is  not  a  process  of  preservation,  liut  of 
slow  destruction.  It  is  an  oxidation  in  which  all  the  escaping  gases  are  so  thoroughly  oxi- 
dized, that  none  of  them  have  any  smell  or  any  oflensive  property.  But  being  so,  the  body 
disinfected  must  necessarily  decay,  and  in  reality  the  process  of  decay  is  remarkably  in- 
creased. All  such  bodies  must  therefore  be  avoided  when  manures  are  to  be  disinfected,  as 
the  valuable  ingredients  are  destroyed  instead  of  being  preserved.  Stenhouse  has  enipl()\  ed 
charcoal  for  disinfecting  the  air.  The  air  is  passed  through  the  charcoal  either  on  a  large 
scale  for  a  hospital,  or  on  a  small  scale  as  a  respirator  for  the  mouth.  Care  must  be  taken, 
however,  to  keep  the  charcoal  dry :  wet  charcoal  is  not  capable  of  absorbing  air  until  that 
air  is  dissolved  in  the  water.  This  solution  takes  place  less  rapidly  in  water.  Wet  charcoal 
is  therefore  a  filter  for  fluids  chiefly,  and  dry  charcoal  for  vapors.  Its  destructive  action  on 
manures  will,  however,  always  prevent  charcoal  from  being  much  used  as  a  disinfectant  for 
such  purposes,  or,  indeed,  any  other  suljstance  which  acts  principally  by  its  porosity  or  by 
oxidation.  This  the  soil  does  only  partially,  as  it  has  another  power,  viz.,  that  of  retaining 
organic  substances  fit  to  l)e  the  food  of  plants.  Although  air  acts  partly  in  conjunction  with 
the  soil  and  the  rain  to  cause  disinfection,  and  partly  by  its  own  power,  it  also  acts  mechani- 
cally as  a  means  of  removing  all  noxious  vapors.  The  wind  and  other  currents  of  the  air 
are  continually  ventilating  the  ground,  and  when  these  movements  are  not  sufficiently  rapid, 
or  when  they  are  interrupted  by  our  mode  of  building,  we  are  compelled  to  cause  them 
artificially,  and  thus  we  arrive  at  the  art  of  ventilation.  The  addition  of  one-tenth  of  a  per 
cent,  of  carbonic  acid  to  the  air  may  be  perceived,  at  least  if  accompanied  with  the  amount 
of  organic  matter  usually  given  out  at  the  same  time  in  the  breath  ;  and  as  we  exhale  in  a 
day  20  cubic  feet  of  carbonic  acid,  w-e  can  injure  the  quality  of  20,000  cubic  feet  of  air  in 
that  time.  The  great  value  of  a  constant  change  of  air  is  therefore  readily  proved,  and  tl;e 
instinctive  love  which  we  have  of  fresh  air  is  a  sufficient  corroboration. 

Cold  is  a  great  natural  disinfectant.  The  flesh  of  animals  may  be  preserved,  as  far  as 
we  know,  for  thousands  of  years  in  ice  ;  putrefying  emanations  are  completely  arrested  by 
freezing,  but  the  mobility  of  the  particles,  or  chemical  action,  is  also  retarded  by  a  degree 
of  cold  much  less  than  freezing. 

Heat  is  also  a  disinfectant,  when  it  rises  to  about  140°  of  Fahrenheit,  according  to  Dr. 
Ilcnry.  But  as  a  means  of  producing  dryness  it  is  a  disinfectant  at  various  temperatures. 
Nothing  which  is  perfectly  dry  can  undergo  putrefaction.  On  the  other  hand,  heat  with 
moisture  below  140°  is  a  condition  very  highly  productive  of  decomposition  and  all  its 
resulting  evils.  Disinfection  by  heat  is  used  at  quarantine  stations.  Light  is  undoubtedly 
a  great  disinfectant ;  so  far  as  we  know,  it  acts  by  hastening  chemical  decomposition.  In 
all  cases  of  ventilation,  it  is  essential  to  allow  the  rays  of  light  to  enter  with  the  currents 
of  air.  Its  effect  on  the  vitality  of  the  human  being  is  abundantly  proved,  and  is  continu- 
ally asserting  itself  in  vegetation.  The  true  disinfecting  property  of  light  exists  in  all 
jirobability  in  the  chemical  rays  which  cause  compositions  and  decompositions.  Water, 
iiowever,  is  of  all  natural  disinfectants  the  most  manageable,  and  there  is  no  one  capable  of 
taking  its  place  actively.  Wherever  animals,  even  human  beings,  live,  there  are  emanations 
of  organic  matter,  even  from  the  purest.  The  whole  surface  of  the  house,  furniture,  floor, 
and  walls,  becomes  coated  by  degrees  with  a  thin  covering,  and  this  gradually  decomposes, 
and  gives  off  unpleasant  vapors.  Sometimes  it  becomes  planted  with  fungi,  and  so  feeds 
plants  of  this  kind.  But  long  before  this  occurs  a  small  amount  of  vapor  is  given  off  suffi- 
ciently disagreeable  to  affi:?ct  the  senses,  and  sometimes  afl'ecting  the  spirits  and  the  health 
before  the  senses  distinctly  perceive  it.  This  must  be  removed.  In  most  cases  this  film  is 
removed  hj  water,  and  we  have  the  ordinary  result  of  household  cleanliness ;  but  in  other 
cases,  when  the  furniture  is  such  as  will  be  injured  by  water,  tlic  removal  is  made  by  fric- 
tion, or  by  oil  or  turpentine,  and  other  sutistances  used  to  polish.  Water  as  a  disinfectant 
is  used  also  in  washing  of  clothes  ;  for  this  purpose  nothing  whatever  can  supply  its  place, 
a'thougli  it  requires  the  assistance  both  of  soap  and  friction,  or  agitation  and  heat.  Water 
is  also  used  as  a  mechanical  agent  for  removing  filth,  and  the  method  which  Hercules  de- 
vised of  using  a  river  to  wash  away  filth,  is  now  adopted  in  all  the  most  advanced  plans  of 
cleansing  towns.  It  is  only  by  means  of  water  that  the  refuse  of  towns  can  be  conveyed 
away  in  covered  and  impeijirious  passages,  whilst  none  whatever  is  allowed  to  remain  in  the 
town  itself.  In  cases  where  this  cannot  be  done,  it  is  much  to  be  desired  that  some  disin- 
fecting agent  should  be  used  to  prevent  decomposition.  Where  water  is  not  used,  as  in 
water-closets,  there  must  of  course  be  a  great  amount  of  matter  stored  up  in  middens,  and 
the  town  is  of  course  continually  exposed  to  the  effluvia.  Besides  these  methods  of  acting, 
water  disinfects  partly  by  preventing  effluvia  from  arising  from  bodies,  simply  because  it 
keeps  them  in  solution.     This  action  is  not  a  perfect  one,  but  one  of  great  value.     The 


DISINFECTANT.  451 

water  gives  off  the  impurity  slowly,  sometimes  so  slowly  as  to  be  of  no  injury,  or  it  keeps 
it  so  long  that  complete  oxidation  takes  place.  The  oxygen  for  this  purpose  is  supplied  by 
the  air,  which  the  water  absorbs  without  ceasing.  To  act  in  this  way,  water  must  be 
delivered  in  abundance  ;  when  only  existing  as  a  moisture,  water  may  act  as  a  great  oppo- 
nent to  disinfection  by  rising  up  iu  vapor  loaded  with  tlie  products  of  decomposition. 

Mere  drying  is  known  to  arrest  decay,  as  the  mobility  of  the  particles  in  decomposition 
is  stayed  by  the  want  of  water.  We  are  told  in  Anderssen's  Travels  iu  South  Africa,  that 
the  Damaras  cut  their  meat  into  strips,  and  dry  it  in  the  sun,  by  which  means  it  is  preserved 
fresh.  A  similar  custom  is  found  in  South  America.  Certain  days  prevent  this,  and  de- 
composition sets  in  rapidly.  A  little  overclouding  of  the  sky,  or  a  little  more  moisture  in 
the  air,  quickly  stops  the  process. 

The  above  may  be  called  natural  disinfectants,  or  imitations  of  natural  processes,  char- 
coal being  introduced  as  an  example  of  a  more  decided  character  of  porous  action.  They 
show  both  mechanical  and  chemical  action.  The  mechanical,  when  water  or  air  removes, 
dilutes,  or  covers  the  septic  bodies :  the  chemical,  when  porous  bodies  act  as  conveyers  of 
oxygen :  or  an  union  of  both,  when  cold  and  heat  prevent  the  mobility  of  the  particles. 
The  action  by  oxidation  causes  a  destruction  of  the  offensive  material.  The  other  method 
is  antiseptic.  It  is  much  to  be  desired  that  all  impurities  should  be  got  rid  of  by  some  of 
these  methods,  but  especially  by  the  air,  the  water,  and  the  soil.  There  are,  however,  con- 
ditions in  which  difficulties  interfere  with  the  action.  Large  towns  may  be  purified  by 
water,  but  wiiat  is  to  be  done  with  the  water  which  contains  all  the  impurity  ?  If  put  upon 
land,  it  is  very  soon  disinfected,  but  on  its  way  to  the  land  it  may  do  much  mischief.  It 
has  been  proposed  to  disinfect  it  on  its  passage,  and  even  in  the  sewers  themselves  ;  by  this 
means  the  town  itself  is  freed  from  the  nuisance,  and  the  water  may  be  used  where  it  is 
needed  without  fear.  This  introduces  artificial  disinfectants.  There  are  other  cases  where 
such  are  required — when  the  refuse  matter  of  a  town  is  allowed  to  lie  either  in  exposed  or 
in  underground  receptacles ;  in  this  case  a  town  is  exposed  to  an  immense  surface  of  im- 
purity, and  disinfectants  would  greatly  diminish  the  evil,  if  not  entirely  remove  it.  There 
are,  besides,  special  cases  without  end  continually  occurring,  where  impurities  cannot  be  at 
once  removed,  and  where  treatment  with  artificial  disinfectants  is  required. 

Artificial  disinfectants  which  destroy  the  compound,  are  of  various  kinds.  J^re  is  one 
of  the  most  powerful.  A  putrid  body,  when  heated  so  as  to  be  deprived  of  all  volatile  par- 
ticles, cannot  any  longer  decompose.  It  is  however  possible  that  the  vapors  may  become 
putrid,  and  if  not  carefully  treated,  this  will  happen.  It  was  the  custom  of  some  of  the 
wealthy  among  the  ancients  to  burn  the  dead,  and  it  is  still  the  custom  in  India ;  Ijut 
although  the  form  is  kept  up  amongst  all  classes,  the  expense  is  too  great  for  the  poor. 
The  bodies  are  singed,  or  even  less  touched  by  fire,  and  thrown  if  possible  into  the  river. 
This  process  has  been  recommended  here,  but  the  quality  of  the  gaseous  matter  rising  from  a 
dead  body,  is  most  disgusting  to  our  phvsical,  and  still  more  to  our  moral  senses,  and  the 
amount  is  enormous.  It  is  of  course  possible  so  to  burn  it,  that  only  pure  carbonic  acid, 
water,  and  nitrogen,  shall  escape ;  but  the  probability  of  preventing  all  escape  is  small 
enough  to  be  deemed  an  impossibility,  and  the  escape  of  one  per  cent,  would  cause  a  rising 
of  the  whole  neighborhood.  To  effect  the  combustion  of  the  dead  of  a  great  city,  such  a 
large  work,  furnished  with  great  and  powerful  furnaces,  would  be  required,  that  it  would 
add  one  of  the  most  frightful  blots  to  modern  civilization,  instead  of  the  calm  and  peaceful 
churchyard,  where  our  bones  are  preserved  as  long  at  least  as  those  who  care  for  us  live, 
and  then  gradually  return  to  the  earth.  In  burning  the  dead,  some  prefer  to  burn  the  whole 
body  to  pure  ash.  This  was  the  ancient  method  ;  but  it  is  highly  probable  that  the  ashes 
which  they  obtained  were  a  delusion  in  most  cases.  The  amount  of  ash  found  in  the  urns 
is  often  extremely  small.  The  body  cannot  be  reduced  to  an  infinitesimal  ash,  as  is  sup- 
posed ;  eight  to  twelve  pounds  of  matter  remain  from  an  average  man  when  all  is  over.  A 
second  plan,  is  to  drive  off  all  volatile  matter,  and  leave  a  cinder.  This  disgusting  plan 
leaves  the  body  black  and  incorruptible.  It  can  never,  in  any  time  known  to  us,  mix  with 
its  mother  earth,  and  yet  ceases  at  once  to  resemljle  humanity  in  the  slightest  degree  ;  it 
will  not  even  for  a  long  time  assist  us  by  adding  its  composition  to  the  fertility  of  the  soil. 
The  burning  of  bodies  never  could  have  been  general,  and  never  can  be  general,  l^'we  has 
only  a  limited  use  as  a  disinfectant.  It  cannot  be  used  in  the  daily  disinfection  of  the 
dejecta  of  animals,  and  is  applied  only  occ;isionally,  where  the  most  ra])id  destruction  is  the 
most  desirable,  either  because  the  substance  has  no  value,  or  it  is  too  disgusting  to  exist,  or 
the  products  afti'r  burning  arc  not  offensive.  There  are  two  methods  of  using  fire,  char- 
ring or  burning  to  ashes.     The  second  is  an  act  of 

Oxidation. — This  is  effected  either  by  rapid  combustion  called  fire ;  by  slow  combus- 
tion, the  natural  action  of  the  air  ;  or  by  chemical  agency,  sometimes  assisted  by  mechani- 
cal. Slow  oxidation  in  the  soil  is  a  process  which  is  desirable  in  every  respect,  and  it  would 
be  well  if  we  could  bring  all  offensive  matter  into  this  con<lition  ;  the  annnonia  is  preserved, 
or  it  is  in  part  oxidized  into  nitric  acid  and  water,  both  the  ammonia  and  nitric  acid  being 
food  for  plants.     Sometimes  this  process  is  hastened  by  mixing  up  the  manure  with  alkaline 


452  DISIXFECTAXT. 

substances,  raising  it  in  heaps,  and  watering,  by  this  means  forming  nitrates,  a  process  per- 
formed abundantly  in  warm  countries  upon  the  materials  of  plants  and  animals,  and  imitated 
even  in  temperate  regions  with  success.  This  amount  of  oxidation  destroys  a  good  deal  of 
the  carbonaceous  substances,  and  leaves  less  for  the  land.  It  is  only  valuable  when  salt- 
petre is  to  be  prepared. 

One  of  the  most  thorough  methods  of  oxidation,  is  by  the  use  of  the  manganates  or 
permanganates.  They  transfer  their  oxygen  to  organic  substances  with  great  rapidity,  and 
completely  destroy  them.  They  are  therefore  complete  disinfectants.  They  destroy  the 
odor  of  putrid  matter  rapidly,  and  oxidize  sulphuretted  hydrogen,  and  phosphuretted  hydro- 
gen, as  well  as  purely- organic  substances.  As  they  do  this  by  oxidation  at  a  low  tempera- 
ture, they  are  the  mildest  form  of  the  destructive  disinfectants,  and  their  application  to 
putrid  liquids  of  every  kind  will  give  most  satisfactory  results.  The  quantities  treated  at  a 
time  should  not  be  great,  and  the  amount  of  material  used  must  be  only  to  the  point  of 
stopping  the  smell,  or  at  least  not  much  more,  because  both  pure  and  impure  matter  act  on 
the  manganates,  and  an  enormous  amount  of  the  material  may  be  used  in  destroying  that 
which  is  not  at  all  offensive.  The  manganates  do  not  prevent  decay  from  beginning  again. 
Their  use  has  been  patented  by  Mr.  Condy.  A  similar  action  takes  place  with  various  high 
oxides  and  other  oxides  which  are  not  high.  Sometimes,  however,  a  deleterious  gas  is  pro- 
duced, as  a  secondary  result  by  oxidation,  as  when  sulphuric  acid  in  the  sulphates  oxidizes 
organic  matter,  allowing  sulphuretted  hydrogen  to  escape.  In  this  case  it  is  highly  probable 
that  a  true  disinfection  takes  place,  or  a  destruction  of  the  putrid  substance,  and  all  offen- 
sive purely  organic  substances ;  still  the  amount  of  sulpuretted  hydrogen  given  off,  is  of 
itself  sufficiently  offensive  and  deleterious,  although  not,  properly  speaking,  an  infectious  or 
putrid  gas,  but  an  occasional  accompaniment. 

Nitric  acid  is  another  agent  of  destruction  or  oxidation,  although  it  has  qualities  which 
might  cause  it  to  be  ranked  amongst  those  which  prevent  the  decomposition  by  entering 
into  new  combinations.  But  properly  speaking,  it  is  not  nitric  acid  which  is  the  disinfectant 
of  Carmichael  Smyth,  but  nitric  oxide,  which  is  a  powerful  oxidizer,  and  most  rapidly  de- 
stroj's  organic  matter.  For  very  bad  cases,  in  which  gaseous  fumigation  is  applicable,  noth- 
ing can  be  more  rapid  and  effective  in  its  action  than  this  gas.  Care  must  be  taken  that 
there  is  no  one  present  to  breathe  it,  as  it  has  a  powerful  action  on  the  lungs,  and  care  must 
be  taken  that  metallic  surfaces  which  are  to  be  preserved  clean,  be  well  covered  with  a  coat- 
ing of  varnish.  This  was  used  with  great  effect  in  ships  and  hospitals  for  some  years,  be- 
ginning with  17S0,  and  so  much  good  did  it  do,  that  the  Parliament  in  1802  voted  Dr.  C. 
Smyth  a  pension  for  it.  Guyton-Morveau  was  vexed  at  this,  and  wrote  an  interesting  vol- 
ume concerning  his  mode  of  fumigating  by  acids  ;  but  in  reality  acids  alone  are  insufficient, 
and  his  favorite  muriatic  acid  has  no  such  effect  as  nitrous  fumes,  which  so  readily  part  with 
their  oxygen. 

Chlorine  is  another  destructive  agent,  and  its  peculiar  action  may  be  called  an  oxidation. 
When  used  as  a  gas,  it  has  a  great  power  of  penetration,  like  nitrous  fumes,  and  stops  all 
putrefaction.  It  has  a  more  actively  destructive  power  than  oxygen  alone,  even  when  its 
action  is  that  of  oxidation  only.  It  decomposes  compounds  of  ammonia  into  water  and 
nitrogen,  and  as  putrefactive  niatter  is  united  with,  or  composed  partly  of  nitrogen,  it  de- 
stroys the  very  germ  of  the  evil.  By  the  same  power  it  destroys  the  most  expensive  part 
of  a  manure,  the  ammonia.  It  cannot  therefore  be  used  where  the  offensive  matter  is  to 
be  retained  for  manure.  When  chlorine  is  united  with  lime  or  soda,  it  may  be  used  either 
as  a  powder  in  the  first  case,  or  as  a  liquid  in  either  case.  For  direct  application  to  the 
offensive  substances,  a  solution  is  used,  or  the  powder.  This  latter  acts  exactly  as  the 
gaseous  chlorine,  but  the  power  of  destroying  ammonia  is  greater.  As  a  liquid,  it  acts  too 
rapidly ;  as  a  solid,  the  chloride  of  lime  soon  attracts  moisture,  and  soon  loses  its  power. 
Some  people  use  the  chloride  of  lime  as  a  source  of  chlorine ;  they  pour  sulphuric  acid  on 
it,  and  so  cause  it  to  give  out  chlorine,  which  escapes  as  a  gas,  and  acts  as  aforesaid.  This 
has  not  been  found  agreeable,  or  indeed  more  than  partifilly  useful.  Too  much  is  given  out 
at  first,  too  little  at  last.  It  is  said  to  have  increased  the  lung  diseases  at  h.ospitals,  where 
it  was  much  used  in  Paris.  When  only  a  minute  cjuantity  of  gas  is  given  out,  as  at  bleach 
works,  jt  certainly  causes  a  peculiar  freshness  of  feeling,  and  the  appearance  of  the  people 
is  much  in  its  favor,  nor  has  it  ever  there  been  known  to  affect  the  lungs.  For  violent 
action,  in  cases  of  great  impurity,  it  is  a  great  disinfectant,  and  to  be  preferred  to  nitrous 
fumes,  probably  causing  a  less  powerful  action  on  the  lungs.  £au  de  javelle  is  a  chloride 
of  potash  used  in  Paris.  Sometimes  oxygen,  or  at  least  air,  is  used  alone,  to  remove  both 
color  and  smell,  oils  having  it  pumped  into  them.  Sometimes  acids  alone  are  used  for  dis- 
infection. As  putrid  compounds  contain  ammonia  or  organic  bases,  they  may  be  removed, 
or  at  least  they  may  be  retained  in  combination,  and  in  this  way  restrained  from  further 
evaporation.  This  seems  to  be  the  way  in  which  muriatic  acid  acts,  and  all  other  merely 
acid  agents.  This  acid,  so  much  valued  at  one  time,  is  now  entirely  disused,  as  it  ought  to 
be,  because  it  is  exceedingly  disagreeable  to  breathe,  and  destructive  of  nearly  all  useful 
substances  which  it  touches,  being  at  the  same  time  a  very  indirect  disinfectant.     Acids 


DISINFECTANT.  453 

poured  on  putrid  matters,  no  doubt  destroy  the  true  putrefaction,  but  they  cause  the  evolu- 
tion of  gases  exceedingly  nauseous,  and  of  course  unwholesome.  This  evolution  does  not 
last  long,  but  long  enough  to  make  them  useless  as  disinfectants  when  used  so  strong. 
Vinegar  is  the  best  of  the  purely  acid  disinfectants ;  wood  vinegar  the  best  of  the  vinegars, 
because  it  unites  to  the  acidity  a  little  kreasote.  Vinegar  is  a  very  old  and  well-established 
agent ;  it  has  been  used  in  the  case  of  plague  and  various  pestilences  from  time  immemo- 
rial. It  is  used  to  preserve  eatables  of  various  kinds.  For  fumigation,  no  acid  vapor  used 
is  pleasant  except  vinegar,  and  in  cases  where  the  impurity  is  not  of  the  most  violent  kind, 
it  may  be  used  with  great  advantage.  Even  this,  however,  acts  on  some  bright  surfaces,  a 
disadvantage  attending  most  fumigations. 

Sulphurous  Acid,  or  the  fumes  of  burning  sulphur,  may  be  treated  under  this  head, 
although  in  reality  it  does  not  act  as  a  mere  acid  combining  with  a  base  and  doing  no  more. 
It  certainly  unites  with  bases  so  that  it  has  the  advantage  of  an  acid,  but  it  also  decomposes 
by  precipitating  its  sulphur,  as  wlien  it  meets  sulphuretted  hydrogen.  It  therefore  acts  as 
an  oxidizer  in  some  cases,  but  it  is  generally  believed,  from  its  desire  to  obtain  oxygen,  that 
it  acts  by  being  oxidized,  thus  showing  the  peculiar  characteristics  of  a  deoxidizer.  We 
can  certainly  believe  that  bodies  may  be  disinfected  both  by  oxidation  and  deoxidation.  The 
solutions  of  sulphurous  acid  act  as  a  restraint  on  oxidation,  and  preserve  like  vinegar.  Its 
compounds  with  bases,  such  as  its  salts  of  soda,  potash,  &c.,  preserve  also  like  vinegar,  salt- 
petre, &c.  ;  probably  from  their  affiuity  for  oxygen,  taking  what  comes  into  the  liquid  before 
the  organic  matter  can  obtain  it.  But  it  is  not  probable  that  this  rivalry  exists  to  a  great 
extent ;  the  presence  of  the  sulphurous  acid  in  all  probability  puts  some  of  the  particles  of 
oxygen  in  the  organic  matter  in  a  state  of  tension  or  inclination  to  combine  with  it,  so  that 
the  tension  of  the  particles  which  are  inclined  to  combine  with  the  oxygen  of  the  air  is 
removed. 

Sulphur  fumes  are  amongst  the  most  ancient  disinfectants  held  sacred  in  early  times 
from  their  wonderful  efficacy,  and  still  surpassed  by  none.  With  sulphur  the  shepherd 
purified  or  disinfected  his  flocks,  and  with  sulphur  Ulysses  disinfected  the  suitors  which  he 
had  slain  in  his  house.  No  acid  fumigation  is  less  injurious  generally,  vinegar  excepted,  to 
the  lungs  or  furniture,  and  its  great  efficiency  marks  it  out  as  the  most  desirable,  although 
much  laid  aside  in  modern  times.  The  amount  arising  from  burning  coal  must  have  a  great 
effect  in  disinfecting  the  putrid  air  of  our  streets,  and  rendering  coal-burning  towns  in  some 
respects  less  unpleasant ;  this  is  one  of  the  advantages  which  that  substance  brings  along 
with  it,  besides,  it  must  be  confessed,  greater  evils.  It  is  curious  that  this  compound  of 
sulphur  should  be  one  of  the  most  efficient  agents  in  destroying  sulphuretted  hydrogen, 
another  compound  of  sulpliur.  Sulphurous  acid  prevents  decomposition,  and  also  preserves 
the  valuable  principle  of  a  manure,  so  that  it  belongs  partly  to  the  class  of  disinfectants, 
and  partly  to  antiseptics. 

The  peculiar  actions  of  sulphurous  acid  and  kreasote  have  been  united  in  that  called 
"  McDougall's  Disinfecting  Powder."  Since  in  towns  and  farms,  when  disinfectants  are 
used,  it  is  desirable  not  to  use  liquids,  these  two  have  been  united  into  a  powder,  which 
assists  also  in  removing  moisture,  as  water  is  often  a  great  cause  of  discomfort  and  disease 
in  stables  and  cowhouses.  When  they  are  used  in  this  manner,  the  acids  are  united  with 
lime  and  magnesia.  When  the  floors  of  stables  are  sanded  with  the  powder,  it  becomes 
mixed  with  the  manure,  which  does  not  lose  ammonia,  and  is  found  afterwards  much  more 
valuable  for  land.  The  cattle  are  also  freed  from  a  great  amount  of  illness,  because  the  air 
of  the  stable  is  purified.  When  fasces  of  any  kind  cannot  be  at  once  removed  by  water,  as 
by  the  water-closet  system,  the  use  of  this  is  invaluable ;  but  it  is  well  to  know  that  the 
instant  removal  of  impurity  by  water  is  generally  best  for  houses,  however  difficult  the  after 
problem  may  be  when  the  river  is  polluted.  In  stables  and  cowhoiises  this  is  not  the  case, 
and  it  is  then  that  a  disinfecting  powder  becomes  so  valuable,  although  it  is  true  that  so 
many  towns  are  unfortunately  so  badly  supplied  with  water-closets  that  disinfectants  arc  still 
much  wanted  for  the  middens. 

The  inventors  have  proposed  to  disinfect  sewers,  as  well  as  sewage,  by  the  same  sub- 
stances ;  not,  however,  in  the  state  of  a  powder.  They  apply  the  acids  to  the  sewage  water 
in  the  sewers  themselves,  and  so  cause  the  impure  water  to  pass  disinfected  through  the 
town  ;  by  tliis  means  the  towns  and  sewers  are  purified  together.  When  the  sewage  water 
is  taken  out  of  tin;  town  it  can  he  dealt  with  either  by  precipitation  or  otherwise.  As  it 
will  cease  to  be  a  nuisance,  covered  passages  for  it  will  not  require  to  be  made. 

Lime  is  used  for  precipitating  sewage  water,  and  acts  as  a  disinfectant  as  far  as  the 
removal  of  the  precipitate  extends,  and  also  by  alisorbing  sulphuretted  hydrogen,  which, 
however,  it  allows  again  to  pass  off  gradually.  The  other  sul)stances  proposed  for  sewers 
have  cliiefly  relation  to  the  precipitation,  and  do  not  so  readily  come  under  this  article. 
Charcoal  has  been  mentioned  ;  alum  has  been  proposed,  and  it  certainly  docs  act  as  a  disin- 
fectant and  precipitant.  None  of  these  suljstances  have  been  tried  on  a  great  scale  exwpt- 
ins:  lime. 


454  DISTILLATION. 

Absence  of  Air  is  an  antiseptic  of  great  value.  The  process  of  preserving  nreat,  called 
Appert's  process,  is  by  putting  it  in  tin  vessels  with  water,  boiling  off  a  good  deal  of  steam, 
to  drive  out  the  air,  and  then  closing  the  aperture  with  solder.  Schroeder  and  De  Dusch 
prevented  putrefaction  for  months  by  allowing  no  air  to  approach  the  meat  without  passing 
through  cotton  ;  so  also  veils  are  found  to  be  a  protection  against  some  miasmas.  Salts,  or 
compounds  of  acids  with  bases,  are  valuable  antiseptics ;  some  of  them  are  also  disinfect- 
ants, that  is,  they  remove  the  state  of  putrefaction  after  it  has  begun.  An  antiseptic  pre- 
vents it,  but  does  not  necessarily  remove  it.  Connnon  salt  is  well  known  as  a  preserver  of 
flesh  ;  nitrate  of  potash,  or  saltpetre,  is  a  still  more  powerful  one.  Some  of  these  salts  act 
in  a  manner  not  noticed  when  treating  of  the  preceding  substances,  viz.,  by  removing  the 
water.  Meat,  treated  with  these  salts,  gives  out  its  moisture,  and  a  strong  solution  of  brine 
is  formed.  Chloride  of  calcium  prevents,  to  some  extent,  the  putrefaction  of  wood.  Alum, 
or  the  sulphate  of  alumina,  is  not  a  very  efficient  preserver ;  but  chloride  of  aluminum 
seems  to  have  been  I'ound  more  valuable.  It  is  sometimes  injected  into  animals  by  the 
carotid  artery  and  jugular  vein.  Meat  usually  keeps  a  fortnight :  if  well  packed,  cleaned, 
and  washed  with  a  .solution  of  chloride  of  aluminum,  it  will  keep  three  months. 

But  in  reality  the  salts  of  the  heavier  metals  are  of  more  activity  as  disinfectants.  It 
has  been  supposed  that  their  elhciency  arose  from  their  inclination  to  unite  with  sulphur 
and  phosphorus,  and  there  is  no  doubt  that  this  is  one  of  their  valuable  properties,  by  which 
they  are  capable  of  removing  a  large  portion  of  the  impure  smell  of  bodies  ;  but  they  have 
also  an  inclination  to  combine  with  organic  substances,  and  by  this  means  they  prevent  them 
from  undergoing  the  changes  to  which  they  are  most  prone.  The  actual  relative  value  of 
solutions  it  is  not  easy  to  tell.  Most  experiments  have  been  made  on  solutions  not  suffi- 
ciently definite  in  quantity.  Salts  of  mercury  have  been  found  highly  antiseptic.  Such  a 
salt  is  used  for  preserving  wood  ;  the  process  is  known  as  that  of  Kyan's,  or  kyanizing.  A 
solution  of  corrosive  sublimate,  containing  about  1^  per  cent,  of  the  salt,  is  pressed  into 
the  wood  cither  by  a  forcing  pump  or  by  means  of  a  vacuum.  The  albumen  is  the  substance 
most  apt  to  go  into  putrefaction,  and  when  in  that  condition  it  conveys  the  action  to  the 
wood.  It  is  no  doubt  by  its  action  on  the  albumen  that  the  mercury  chiefly  acts.  Thin 
pieces  of  pine  wood,  saturated  for  four  weeks  in  a  solution  of  1  to  25  water,  with  the  fol- 
lowing salts,  were  found,  after  two  years,  to  be  preserved  in  this  order: — 1.  "Wood  alone, 
brown  and  crumbling.  2.  Alum,  like  No.  1.  3.  Suiphateof  manganese,  like  1.  4.  Chlo- 
ritle  of  zinc,  like  1.  5.  Nitrate  of  lead,  somewhat  firmer.  6.  Sulphate  of  copper,  less 
brown,  firm.  7.  Corrosive  sublimate,  reddish  yellow  and  still  firmer.  In  an  experiment,  in 
which  linen  was  buried  with  similar  salts,  the  linen  was  quite  consumed,  even  the  specimen 
with  corrosive  sublimate.  Other  experiments  showed  salts  of  copper  and  mercury  to  pro- 
tect best. — Gmcliyi. 

Nevertheless,  all  these  metallic  salts  are  found  tiue  preservers  under  other  conditions. 
Chloride  of  manganese,  a  substance  frequently  thrown  away,  may  be  used,  as  Gay-Lussac 
and  Mr.  Young  have  shown,  with  great  advantage,  and  Mr.  Boucherie  has  shown  the 
value  of  the  acetate  of  iron.  Mr.  Boucherie's  process  is  very  peculiar.  lie  feeds  the  tree, 
when  living,  with  the  acetate  of  iron,  by  pouring  it  into  a  trough  dug  around  the  root.  The 
tree,  when  cut  down,  has  its  pores  filled  with  the  salt,  and  the  albumen  in  the  sap  is  pre- 
vented from  decoiTiposing.  For  preservation  of  vegetable  and  animal  substances,  see 
Pdtrf.faction,  Prevention  of. 

The  chloride  of  zinc  of  Sir  William  Burnett  is  also  a  valuable  disinfectant,  and  has  more 
power  than  it  would  seem  to  possess  from  the  experiments  quoted  above.  Wood,  cords, 
and  canvas,  have  been  preserved  hy  it  under  water  for  many  years.  It  has  the  advantage 
also  of  being  so  soluble  as  to  take  up  less  room  than  most  other  salts,  although  liquids  gen- 
erally are  inconvenient  as  disinfectants  in  many  places. 

Nitrate  of  lead  is  a  disinfeetunt  of  a  similar  kind  ;  it  lays  hold  of  sulphur,  and  the  base 
unites  with  organic  compounds.  All  these  metals  are  too  expensive  for  general  use,  and 
can  only  be  applied  to  the  preservation  of  valuable  materials.  Even  iron  is  much  too  dear 
to  be  used  as  a  disinfectant  for  materials  to  be  thrown  on  the  fields  as  manure.  All  are  apt 
to  be  very  acid,  a  state  to  be  avoided  in  a  disinfectant,  unless  when  it  is  applied  to  sub- 
stances in  a  very  dilute  state,  or  in  an  active  putrid  state,  and  giving  out  ammonia. — 
K.  A.  S. 

Sec  also  Sanitary  Economy. 

DISTILL.\TIOX.  Distillation  consists  in  the  conversion  of  any  substance  into  vapor, 
in  a  vessel  so  arranged  that  the  vapors  are  condensed  again  and  collected  in  a  vessel  apart. 

The  word  is  derived  from  the  Latin  dh  and  stillo,  I  drop,  meaning  originally  to  drop  or 
fall  in  drops,  and  is  very  applicable  to  the  i)rocess,  since  the  condensation  generally  takes 
place  dropwise. 

It  is  distinguished  from  sublimation  by  the  confinement  of  the  latter  tenn  to  cases  of 
distillation  in  which  the  product  is  solid,  or,  in  fact,  where  a  solid  is  vaporized,  and  con- 
densed without  visible  liquefaction. 

The  operation  may  simply  consist  in  raising  the  temperature  of  a  mixture  sufficiently  to 


DISTILLATION. 


455 


evaporate  the  volatile  ingredients ;  or  it  may  involve  the  decomposition  of  the  substance 
heated,  and  the  condensation  of  the  products  of  decomposition,  when  it  is  termed  destruc- 
tive distillation ;  in  most  cases  of  destructive  distillation  the  bodies  operated  upon  are  solid^ 
and  the  products  liquid  or  gaseous  ;  it  is  then  called  dry  distillation. 

In  consequence  of  the  diversity  of  temperatures  at  which  various  bodies  pass  into  vapor, 
and  also  according  to  the  scale  on  which  the  operation  has  to  be  carried  out,  an  almost  end- 
less variety  of  apparatus  may  be  employed. 

Whatever  be  the  vaiiety  of  form,  it  consists  essentially  of  three  parts: — the  retort  or 
still,  the  coiulcnser,  and  the  receiver. 

On  the  small  scale,  in  the  chemical  laboratory,  distillation  is  performed  in  the  simplest 
way,  by  means  of  the  common  glass  retort  a,  and  receiver  b,  as  in  Jig.  221.  The  great 
advantages  of  the  glass  retort  are  that  it  admits  of  constant  observation  of  the  materials 
within,  that  it  is  acted  upon  or  injured  by  but  few  substances,  and  may  be  cleaned  generally 
with  facility.     Its  great  disadvantage  is  its  brittleness, 

221 


The  retort  may  be  either  simple,  as  in  Jig.  222,  or  tubulated,  as  in  fig.  221,  {a.) 

Retorts  should  generally  be  chosen  sufficiently  convex  in  all  parts,  the  degree  of  curva- 
ture of  one  part  passing  gradually  into  that  of  the  neighboring  portions,  as  is  represented 
in  the  figure  ;  the  part  to  be  heated  should,  moreover,  be  as  uniform  in  point  of  thickness 
as  possible.  The  tubulated  retort  is  more  liable  to  crack  than  tiie  plain  one,  on  account  of 
the  necessarily  greater  thickness  of  the  glass  in  the  neighborhood  of  the  tubulature  ;  never- 
theless it  is  very  convenient  on  account  of  the  facility  which  it  offers  for  the  introduction 
of  the  materials. 

In  charging  retorts,  if  plain,  a  funnel  with  a  long  stem  should  be  employed,  to  avoid 
soiling  the  neck  with  the  liquid  to  be  distilled :  when  a  solid  has  to  be  introduced,  it  is 
preferable  to  employ  a  tubulated  retort ;  and  if  a  powdered  solid  is  to  be  mixed  with  a  fluid, 
it  is  preferable  to  introduce  the  fluid  first. 

Ileat  may  be  applied  to  the  retort  either  by  the  argand  gas  flame,  as  in  fig.  221,  or  a 
water,  oil,  or  sand-bath  may  be  employed. 

In  distilling  various  substances,  c.  g.,  sulphuric  acid,  great  inconvenience  is  experienced, 
and  even  danger  incurred,  by  the  phenomenon  termed  "  bumping."  This  consists  in  the 
accumulation  of  large  bubbles  of  vapor  at  the  bottom  of  the  liquid,  which  bursting  cause  a 
forcible  expulsion  of  the  liquid  from  the  retort.  It  is  prevented  by  the  introduction  of  a 
few  angular  fragments  of  solid  matter  of  such  a  nature  as  not  to  be  acted  upon  by  the  liquid 
which  is  to  be  distilled.  Nothing  answers  this  purpose  better  than  a  piece  of  platinum  foil 
cut  into  a  fringe,  or  even  a  coil  of  platinum  wire  introduced  into  the  cold  liquid  before  the 
distillation  is  commenced.  Even  with  this  precaution  the  distillation  of  sulphuric  acid, 
which  it  is  often  desirable  to  perform  for  the  purpose  of  its  purification,  is  not  unattended 
with  difficulty  and  danger. 

Dr.  Mohr  suggests  the  following  method*  : — A  glass  retort  of  about  two  pounds'  capacity, 
is  placed  on  a  cylinder  of  sheet-iron  in  the  centre  of  a  small  iron  furnace,  while  its  neck 
protrudes  through  an  opening  in  the  side  of  the  furnace,  ( /ig.  223.)  Ignited  charcoal  is 
placed  round  the  cylinder,  without  being  allowed  to  come  in  contact  with  the  glass,  and  a 
current  of  hot  air  is  thug  made  to  play  on  ail  parts  of  the  retort  excepting  the  bottom,  which 


♦  Mohr  nn<l  Redwood's  Practical  Pharmacy. 


456 


DISTILLATION. 


is  protected  by  its  support.  There  is  a  valve  iu  the  flue  of  the  furnace  for  regulating  the 
draught,  and  three  small  doors  in  the  cupola  or  head,  for  supplying  fresh  fuel  on  every  side, 
and  for  observing  the  progress  of  the  distillation. 

Instead  of  the  sheet-iron  cylinder,  a  Hessian  crucible  may  be  employed,  and  this,  if 
requisite,  elevated  by  placing  it  on  a  brick.  If  the  vapor  be  readily  condensed,  nothing 
more  is  necessary  than  to  insert  the  extremity  of  the  retort  into  a  class  receiver,  as  in 
/^;/.  221.     .  _  fe  , 

It  a  more  efficient  condensing  arrangement  be  requisite,  nothing  is  more  convenient  for 
use  ou  the  small  scale  than  a  Liebig's  condenser,  shown  in  fg.  224.     It  consists  simply  of 


223 


224 


a  long  glass  tube  into  which  the  neck  of  the  retort  is  fitted,  and  the  opposite  extremity  of 
which  passes  into  the  mouth  of  the  receiver ;  round  this  tube  is  fitted  another  either  of 
glass  or  metal,  and  between  the  two  a  current  of  water  is  made  to  flow,  entering  at  a  and 
passing  out  at  b.  The  temperature  of  this  water  may  be  lowered  to  any  required  degree  by 
putting  ice  into  the  reservoir  c,  or  by  dissolving  salts  in  it.     (See  Freezing.) 

Even  on  the  small  scale  it  is  sometimes  necessary  to  employ  distillatory  apparatus  con- 
structed of  other  materials  besides  glass. 

Earthenware  retorts  are  now  constructed  of  very  convenient  sizes  and  shapes.  There  is 
one  kind — which  is  very  useful  when  it  is  required  to  pass  a  gas  into  the  retort  at  the  same 
time  that  the  distillation  is  going  on,  as  in  the  preparation  of  chloride  of  aluminium,  &:c. — 
which  has  a  tube  passing  down  into  it  also  made  of  earthenware,  as  in  Jig.  225.  The 
closest  are  of  Wedgewood  ware,  but  a  common  clay  retort  may  be  made  impermeable  to 
gases,  by  washing  the  surface  with  a  solution  of  borax,  then  carefully  drying  and  heating 
them. 


225 


Retorts,  or  flasks  with  bent  tubes,  which  screw  in  thu?,  {  fif).  220,)  of  copper,  are  em- 
ployed when  it  is  requisite  to  produce  high  temperatures,  as  for  the  preparation  of  benzole 
from  benzoic  acid  and  baryta,  or  in  making  marsh  gas  from  an  acetate,  &c. 

In  distilling  hydrofluoric  acid,  the  whole  apparatus  should  be  constructed  in  lead ;  the 
receiver  consisting  of  a  U-shaped  tube  of  lead,  which  is  fitted  with  leaden  stoppers  so  as  to 
serve  for  keeping  the  acid  when  prepared  ;  or  a  receiver  of  gutta  percha  may  be  employed 
with  a  stopper  of  the  same  material.     {Fig.  227.) 

For  many  purposes  in  the  laboratory,'  as,  for  instance,  the  preparation  of  oxygen  by 


DISTILLATION. 


457 


heating  binoxide  of  manganese, — in  the  manufacture  of  potassium,  &c.,  &e.,  where  high 
temperatures  are  required,  the  iron  bottles  in  wliieh  mercury  is  imported  from  Spain  may 
be  employed,  a  common  gun-barrel  being  screwed  into  tliem  to  act  as  a  delivery  tube  or 
condenser.     {Fig-  228.) 


227 


228 


tfiifc' 


On  a  large  scale  an  almost  endless  variety  of  stills  have  been  and  are  still  employed, 
which  are  constructed  of  different  materials. 

The  common  "  still "  consists  of  a  retort  or  still  proper,  in  which  the  substance  is  heated  ; 
and  a  condenser  commonly  called  a  "  worm,''  on  account  of  its  having  frequently  a  spiral 
shape.  Tlie  retort  or  still  is  generally  made  in  two  parts  ;  the  pan  or  copper,  which  is  the 
part  to  which  heat  is  applied,  and  is  commonly  set  in  a  furnace  of  brickwork,  and  the 
"Acaf/,"  which  is  generally  removed  after  each  operation,  and  refixed  and  luted  upon  tlie 
pan  when  again  used.  The  condenser  or  worm  is  commonly  placed  in  a  tube  or  other  ves- 
sel of  water.     (See  Jjg.  231.) 

The  still  may  be  either  constructed  of  earthenware,  or,  as  is  very  commonly  the  case,  of 
copper,  either  plain  or  electro-plated  with  silver,  according  to  circumstances  ;  less  frequently 
platinum  is  employed. 

The  still  is  either  heated  by  an  open  fire,  as  in  fir).  228,  or,  as  is  now  very  commonly 
the  case,  by  steam.     The  still-pan  {fig.  229)  is  surrounded  by  an  outer  copper  jacket,  and 

229 


steam  is  admitted  between  them  froin  a  steam-Woilrr  imder  any  required  pressure.     In  this 
way  the  temperature  may  l)e  regulated  with  the  greatest  nicety. 

Various  adaptations  for  heating  by  steam  have  been  appropriately  arranged  in  a  very 
convenient  form  by  Mr.  Coffey,  of  Bunliill  Row,  Finsbury,  in  his  so-called  Eseulajiian  Still. 
It  is  in  fact  a  verital)lo  midlum  in  parro^  being  intended  to  afford  to  the  phai'maceutieal 
chemist  the  means  of  conducting  the  processes  of  ebullition,  distillation,  evaporation,  de- 


458 


DISTILLATION. 


siccation,  &c.,  on  the  small  scale,  by  the  heat  of  a  gas-furnace.    The  following  cut  {fig.  230) 
represents  this  apparatus. 


230 


B,  a  burner  supplied  with  gas  by  a  flexible  tube,  c,  the  boiler  or  still,  i,  an  evapo- 
rating pan  fixed  over  the  boiler  and  forming  the  top  of  the  still-head,  k,  a  valve  for  shut- 
ting oft"  the  steam  from  i,  when  it  passes  through  the  tube  m  ;  otherwise  it  would  pass 
through  L,  and  communicate  heat  to  the  drying-closet  o  o,  and  from  thence  to  the  condenser 
T  T.  o  is  a  second  evaporating  pan  over  the  drying-closet.  Another  arrangement  for  dis- 
tilling by  steam  is  shown  in  fig.  231. 

Sometimes  also  distillation  is  effected  by  passing  hot  steam  through  a  worm  contained 
within  the  still,  instead  of  or  in  addition  to,  the  application  of  heat  from  without. 

231 


232 


DISTILLATION. 


459 


The  worm  or  condenser  is  frequently  constructed  of  earthenware,  and  set  in  an  earthen- 
ware vessel ;  these  are  very  convenient  when  the  operation  is  not  to  be  conducted  on  a 
very  large  scale,  and  only  at  a  moderate  temperature.  They  are  now  to  be  obtained  of  all 
manufacturers  of  stone-ware  articles.  More  commonly  the  worm  is  of  copper,  tin,  or  cop- 
per lined  with  silver,  and  in  some  rare  cases,  where  the  liquids  to  be  distilled  act  upon  both 
copper  and  silver,  of  platinum.     {Fie/.  232.) 

A  tube  of  the  shape  shown  in  fig.  233  is  found  more  convenient  than  the  worm,  on 
account  of  its  exposing  a  larger  surface,  and  also  because  it  can  be  placed  into  a  vessel  of  a 
prismatic  form  which  occupies  but  little  space.  The  water  employed  for  condensation 
enters  at  the  bottom  and  passes  out  at  the  top. 


233 


234 


(a 

I 


cz 


D 


TTMTirl 


Gndilia  Condenser  is  represented  in  fp.  234.  It  consists  of  two  conical  vessels  of 
metal,  of  unequal  size,  flie  smaller  being  fixed  within  the  other,  and  the  space  between  them 
closed  at  the  bottom.  These  are  placed  in  a  tub  filled  with  cold  water,  which  comes  in  con- 
tact with  the  inner  and  outer  surfaces  of  the  cones,  while  the  space  between  is  occupied  by 
the  vapor  to  be  condensed.  This  condenser  is  subject  to  the  objection  which  applies  to  the 
common  worm,  that  it  cannot  be  easily  and  efficiently  cleaned. 

To  obviate  this,  Professor  Mitscherlich  has  proposed  a  very  simple  modification  in  its 
form,  in  which  the  inner  cone  is  movable,  so  that,  v/hen  taken  out,  the  intervening  space 
between  it  and  the  outer  cone  can  be  cleaned,  and  then  the  inner  cone  replaced  previously 
to  commencing  an  o])eration. 

Dhtillalion  of  Spirits. — In  the  manufacture  of  m-dent  spirits,  the  alcoholic  liquor  ob- 
tained by  fermentation  of  a  saccharine  solution  is  submitted  to  distillation  ;  the  alcohol, 
being  more  volatile  than  the  water,  passes  over  first,  but  invariably  a  considerable  propor- 
tion of  water  is  evaporated  and  condensed  with  the  alcohol.  To  separate  this  water  to  the 
re(iuired  extent,  it  is  necessary  cither  to  submit  the  product  to  redistillation,  or  to  contrive 
an  apparatus  such  that  the  product  of  this  first  distillation  is  returned  to  the  still  until  a 
spirit  of  the  required  strength  is  obtained. 

One  of  the  earliest  and  simplest  contrivances  for  effecting  the  latter  object  is  the  still 
invented  by  Dorn,  which  is  employed  up  to  the  present  time  in  Germany,  (Jiff.  235.)  a  is 
the  still,  heated  by  the  direct  action  of  the  fire  ;  b  the  head,  from  which  r  conveys  vapor  to 
a  small  refrigerator,  for  the  purpose  of  testing  the  strensjth  of  the  distillate  ;  k  is  an  ordi- 
nary condenser  containing  worm,  &c.  The  intermediate  copper  vessel  answers  two  pur- 
poses ;  the  upper  part  c  forming  a  heater  for  the  wash,  while  the  lower  compartment  d  acts 
as  a  rectifier.  The  heater  c,  when  filled  up  to  the  level  of  the  cock  m,  contains  the  exact 
measure  of  wash  for  charging  the  still ;  the  contents  can  be  constantly  agitated  by  the 
rouser  i.  The  still  and  heater  being  both  charged,  the  vapor  will  at  first  be  completely 
condensed  in  passing  through  the  worm  r/,  and  flowing  into  d  will  close  the  aperture.  When 
the  contents  of  o  become  so  hot  that  no'more  condensation  occurs,  the  vapor  will  escape  by 
bubbling  through  the  llfiuid  in  n,  which  latter  rapidly  becomes  heated  to  the  boiling  point, 
and  evolves  vapors  richer  in  alcohol,  which  in  their  turn  are  condensed  in  k. 

In  this  manner,  by  one  operation,  spirit  containing  about  60  per  cent,  of  alcohol  is  ob- 
tained. 

Of  the  recent  improvements  on  Dorn's  still,  two  only  need  be  described : — Coffey's, 
which  has  in  a  great  measure  replaced  all  others  in  this  country,  and  Derosne's,  which  is 
extensively  employed  in  France. 


4C0 


Coirey's  Still  far  t^urpasses  any  of  those  before  described.  It  was  patented  in  M-'.'.i,  and 
has  ])roved  nioi^t  valuable  to  the  distiller,  since  it  yields  the  strongest  spirit  that  can  be 
obtained  on  tlie  large  scale. 

Its  objects  are  twofold  : — 1st,  to  economize  tlie  heat  as  much  as  possible,  by  exposing 
the  liquid  to  a  very  extended  heated  surface ;  2d,  to  cause  the  evaporation  of  the  alcohol 
from  the  wash  by  passing  a  current  of  steam  through  it. 

The  wash  is  pumped  from  the  "  wash  charger  "  into  the  worm  tube,  which  passes  from 
top  to  bottom  of  the  rectifier.  In  circulating  through  this  tube  its  temperature  is  raised  to 
a  certain  extent.  Arrived  at  the  last  convolution  of  the  tube  in  the  rectifier,  the  wash 
passes  by  tlie  tube  ^r  Ji  in  at  the  top  of  the  "  analyzer."  It  falls  and  collects  upon  the  top 
shelf  until  this  overflows,  whence  it  i'alls  on  to  the  second  shelf,  and  so  on  to  the  bottom.  All 
the  while  steam  is  passed  up  from  the  steam-boiler  through  fine  holes  in  the  shelves,  and 
tln-ough  valves  opening  upwards.  As  the  wash  gradually  descends  in  the  analyzer,  it  be- 
comes rapidly  weaker,  partly  from  condensation  of  the  steam  which  is  passed  into  it,  and 
partly  from  loss  of  alcohol,  either  evaporated  or  expelled  by  the  steam  ;  till,  when  it  arrives 
at  the  bottom,  it  has  parted  with  the  last  traces  of  spirit.  At  the  same  time  the  vapor,  as 
it  rises  through  each  shelf  of  the  analyzer,  becomes  continuously  riclier  in  alcohol,  and  con- 
tiins  less  and  less  water  in  consequence  of  its  condensation  ;  it  then  passes  from  the  top  of 
the  analyzer  in  at  the  bottom  of  the  lower  compartment  of  tlie  rectifier.  Here  it  ascends 
in  a  similar  way,  bubbling  through  the  descending  wash,  mitil  it  arrives  at  f,  above  Mhich 
it  merely  circulates  round  the  earlier  windings  of  the  wash-pipe,  the  low  temperature  of 
wliich  condenses  the  spirit,  which,  collecting  on  the  shelf  at  f,  flows  oft'  by  the  tube  into 
the  finished  spirit  condenser. 

In  order  .still  further  to  economize  heat,  the  water  for  supphing  the  boiler  is  made  to 
pass  through  a  long  coil  of  pipe,  inmiersed  in  boiling-hot  spent  wash,  by  which  means  its 
temperature  is  raised  liefore  it  enters  the  boiler.  In  lact,  the  saving  of  I'uel  by  the  employ- 
ment of  this  still  is  so  great,  that  only  aliout  three-fourths  of  the  quantity  is  consumed  that 
would  be  requisite  for  distilling  any  given  quantity  of  alcohol  in  the  ordinary  still ;  ar.d  Dr. 
Muspratt  estimates  that  in  this  way  a  saving  will  be  eifectcd  throughout  the  kingdom  of  ro 
less  than  140,000  tons  of  coal  per  annum. 

Very  few  persons  have  any  idea  of  the  enormous  size  of  some  of  the  distilleries.  One 
of  Mr.  Coffey's  stills  at  Inverkeithing  works  oft"  2,000  gallons  of  wash  per  liour,  and  one, 
more  recently  erected  at  Leith,  upwards  of  3,000  gallons. 

DcroRvc^x  Still  is  very  similar,  in  the  principle  of  its  action,  to  Coffey's,  differing  in  fact 
only  in  the  mechanical  details  by  means  of  which  the  result  is  obtained. 

It  consists  of  two  stills,  a  and  n,  fir/.  237.  The  mixture  of  steam  and  alcohol  rajiOr 
from  A  passes  into  the  liquid  in  n,  which  it  raises  to  the  boiling  point  The  vapors  from  d 
rise  through  the  dixtillotori/  column  c,  and  n,  (the  recti firafori/  colunni ;)  hence  they  traverse 
the  coils  of  tubing  in  e,  (the  condcnitcr  al{ti  wine-Jicater,)  and  the  alcohol  is  finally  condensed 
liy  traversing  the  worm  in  f,  (the  rrfricjcrator,)  whence  it  is  delivered  at  z.  At  the  same 
time  a  steady  current  of  the  original  alcoholic  liciuor  is  admitted  from  the  reservoir  ii,  into 
the  exterior  portion  of  the  condenser  f,  by  means  of  the  tap,  the  flow  from  which  is  regu- 
lated by  the  ball  cock  r/.  Whilst  condensing  the  syiirit  in  the  worm,  the  wash  has  its  tem- 
perature raised,  especially  in  the  upper  part,  and  thence  it  ascends  by  the  tul)e  h  into  the 
heater  e,  by  the  small  orifices  k  k,  fff.  238,  where  it  is  still  further  heated  by  the  current 
of  heated  alcohol  which  has  risen  into  the  worm  from  the  stills,  whilst  at  the  same  time 


DISTILLATION. 


461 


23f) 


-  'Drrr 


462 


DISTILLATION. 


assistin"-  in  the  condensation  of  the  spirit.  After  performing  its  office  of  condensation,  and 
when  nearly  at  the  boiling  point,  the  alcoholic  liquor  passes  out  by  the  tube  /,  and  is  con- 
ducted to  the  top  of  the  distillatory  column  c.  Here  it  trickles  down  over  a  series  of  len- 
ticular discs  of  metal,  (shown  in  fig.  238,)  so  contrived  as  to  retard  its  progress  into  the 
still  li,  and  yet  permit  the  ascent  of  the  steam.  In  this  distillatory  column  (c,  fifj.  240)  it 
meets  the  steam  rising  from  the  still  b.  The  greater  part  of  its  alcohol  is  expelled,  which, 
traversing  the  scries  of  condensers  before  described,  is  xdtimately  liquefied  and  collected  at 
z ;  but,  to  complete  the  rectification,  it  descends  into  the  still  b,  and,  when  above  a  certain 
level,  {m  m,)  into  a,  which  stills  being  heated  by  a  furnace  beneath,  the  final  expulsion  of 
alcohol  is  accomplished,  and  the  spent  liquor  run  oft"  at  x. 


230 


240 


238 


f^       r^        ^^^^\-k 


/■B, 


lUJ^-ll 


DISTILLATION,  DESTRUCTIVE.  463 

The  details  of  the  construction  of  the  apparatus  employed  in  the  distillation  of  spirits 
have  been  here  given,  since  this  process  is  perhaps  one  of  the  most  important  of  the  kind  ; 
but  various  modifications  are  employed  in  the  distillation  of  other  liquids. 

In  some  cases,  unusually  ell'ectual  condensing  arrangements  are  required,  as  in  the 
manufacture  of  Etiikr,  Ciilokofoum,  Bisulphide  of  Caubon,  and  Bichloride  of  Carbon. 

In  others  higher  temperatures  are  necessary,  as  in  the  distillation  of  sulphuric  acid. 

When  the  liquids  to  be  distilled  are  acid,  or  otherwise  corrosive,  great  care  has  to  be 
taken  especially  that  the  worm  or  other  condenser  is  of  a  material  not  acted  upon  by  the 
acid.     See  Acetic  Acid  and  Sulphuric  Acid. 

The  term  distillation  is  sometimes  applied  to  cases  of  the  volatilization  and  subsequent 
condensation  of  the  metals  either  in  their  preparation  or  purification. 

In  cases  like  mercury,  potassium,  and  sodium,  where  they  are  condensed  in  the  liquid 
state,  or  visibly  pass  through  this  state  before  volatilization,  this  term  is  quite  appropriate  ; 
but  wliere  the  fusing  and  vaporizing  points  nearly  coincide,  as  in  the  case  of  arsenic,  the 
term  sublimation  would  be  more  suitable. 

Nevertheless  it  is  difficult  to  draw  a  precise  line  of  demarcation  between  the  two  terms ; 
for  in  the  cases  of  zinc,  cadmium,  &c.,  the  metals  being  melted  before  volatilization,  and 
condensed  likewise  in  the  liquid  state,  the  term  is  certainly  correct. 

For  the  details  of  construction  of  the  distillatory  apparatus,  we  must  refer  to  the  articles 
on  these  several  metals. 

DisttUlatio  per  descensum  is  a  term  improperly  applied  to  certain  cases  of  distillation 
where  the  vapor  is  dense,  and  may  be  collected  by  descending  through  a  tube  which  has  an 
opening  in  the  top  of  the  distillatory  vessels,  and  descends  through  the  body  of  the  vessel 
in  which  the  operation  of  evaporation  is  going  on,  being  collected  below. 

This  is  clearly  merely  due  to  the  fact  of  the  vapor  being  even  at  a  high  temperature 
more  dense  than  atmospheric  air,  and  might  be  performed  with  any  body  Ibrming  a  dense 
vapor,  such  as  mercury,  iodine,  zinc,  &c. 

It  has,  however,  practically  been  confined  to  the  English  process  of  refining  zinc.  See 
Zinc. 

The  two  most  remarkable  cases  in  which  the  process  of  destructive  distillation  is  carried 
out  on  a  manufacturing  scale,  are  the  dry  distillation  of  wood,  for  the  manufacture  of  wood 
charcoal,  acetic  acid,  and  pyroxilic  spirit,  (which  see ;)  and  of  coal,  for  the  purpose  of 
obtaining  coal-gas,  and  coke.  This  process  will  be  found  fully  described  in  the  article  on 
Coal-Gas. 

Distillation  of  Esaential  Oils  or  Essences. — The  separation  of  volatile  flavoring  oils 
from  plants,  &c.,  by  distillatiou  with  water,  will  be  fully  treated  under  another  head.  See 
Perfumery,  Essences. 

Fraclio7ial  Distillation. — A  process  for  the  separation  of  volatile  organic  substances 
(such  as  oils)  is  very  extensively  employed  in  our  naphtha  works  under  this  name. 

If  we  have  two  volatile  bodies  together,  but  differing  appreciably  in  their  boiling 
points,  we  find,  on  submitting  them  to  distillation  in  a  retort,  through  the  tubulature  of 
which  a  thermometer  is  fixed,  so  that  its  bulb  dips  into  the  Uquid,  that  the  temperature 
remains  constant  (or  nearly  so)  at  the  point  at  which  the  more  volatile  constituent  of  the 
mixture  boils,  and  the  distillate  consists  chiefly  of  this  more  volatile  ingredient ;  and  only 
after  nearly  the  whole  of  it  has  passed  over,  the  temperature  rises  to  the  point  at  which  the 
less  volatile  body  boils.  Before  this  point  has  been  reached,  the  receiver  is  changed,  and 
the  second  distillate  collected  apart.  By  submitting  the  first  product  to  repeated  redistilla- 
tion, as  long  as  its  boiling  point  remains  constant,  the  more  volatile  constituent  of  the  mix- 
ture is  ultimately  obtained  in  a  state  of  absolute  purity.     See  Naphtha. 

This  method  may  in  fact  be  adopted  when  the  mixture  contains  several  bodies ;  and  by 
changing  the  receiver  with  each  distinct  rise  of  temperature,  and  repeating  the  process  sev- 
eral times,  a  fractional  separation  of  the  constituents  of  the  mixture  may  be  effected. — 
II.  M.  W. 

DISTILLATION,  DESTRUCTIVE.  Organic  matters  may  be  divided  into  two  groups, 
founded  on  their  capability  of  withstanding  high  temperatures  without  undergoing  molecular 
changes.  Bodies  that  distil  unchanged  form  the  one,  and  those  which  break  up  into  new 
and  simpler  forms,  the  other.  The  manner  in  which  heat  acts  upon  organic  substances  dif- 
fers not  only  with  the  nature  of  the  matters  operated  u[)on,  but  also  with  the  temperature 
employed.     We  shall  study  the  subject  under  the  following  heads : — 

1.  Apparatus  for  Destructive  Distillation. 

2.  Destructive  Distillation  of  Vegetable  Matters. 

3.  Destructive  Distillation  of  Animal  Matters. 

4.  Destructive  Distillation  of  Acids. 

5.  Destriictive  Distillation  of  Bases. 

6.  General  Remarks. 

1.  Apparatus  for  Destructive  Distillation. — Destructive  distillation  on  a  large  scale  is 


461  DISTILLATION,  DESTRUCTIVE. 

most  conveniently  performed  in  the  cast-iron  retorts  used  in  gas  works.  Where  quantities 
of  materials  not  exceeding  fifteen  or  twenty  pounds  are  to  be  operated  on,  for  the  purpose 
of  research,  a  more  handy  apparatus  can  be  made  from  one  of  the  stout  cast-iron  pots  sold 
at  the  iron  wharves.  They  are  semi-cylindrical,  and  have  a  broad  flange  round  tlie  edge. 
The  cover  should  be  made  to  fit  in  the  manner  of  a  saucepan  lid.  The  aperture  by  which 
the  products  of  distillation  are  to  be  carried  away  should  be  of  good  size,  and  the  exit  pipe 
must  not  rise  too  high  above  the  top  of  the  pot  before  it  turns  down  again.  This  is  very 
essential  in  order  to  prevent  the  less  volatile  portion  of  the  distillate  from  condensing  and 
falling  back.  The  exit  tube  should  conduct  the  products  to  a  receiver  of  considerable 
capacity,  and  of  such  a  form  as  to  enable  the  solid  and  fluid  portions  of  the  distillate  to  be 
easily  got  at  for  the  purpose  of  examination.  From  the  last  vessel  another  tube  should  con- 
duct the  more  volatile  products  to  a  good  worm  supplied  with  an  ample  stream  of  cold 
water.  If  it  be  intended  to  examine  the  gaseous  substances  yielded  by  the  substances  under 
examination,  the  exit  pipe  of  the  worm  must  be  connected  with  another  apparatus,  the 
nature  of  which  must  depend  on  the  class  of  bodies  which  are  expected  to  come  over.  If 
the  most  volatile  portions  arc  expected  to  be  basic,  it  will  be  proper  to  allow  them  to  strei.ii; 
through  one  or  more  Woulfe's  Ijottles  half  filled  with  dilute  hydrochloric  acid.  Any  vtiy 
volatile  hydrocarbons  of  the  Cnlln  family  which  escape  may  be  arrested  by  means  of  bro- 
mine water  contained  in  another  Woulfe's  bottle.  The  pressure  in  the  Woulfe's  bottles 
must  be  prevented  from  becoming  too  great,  or  the  leakage  between  the  flange  of  the  pot 
and  its  cover  will  be  very  considerable.  The  luting  may  consist  of  finely  sifted  Stourbridge 
clay,  worked  up  with  a  little  horse  dung.  A  few  heavy  weights  should  be  placed  on  various 
parts  of  the  lid  of  the  pot,  so  as  to  keep  it  close,  and  render  the  leakage  as  little  as  pos- 
sible. For  the  destructive  distillation  of  small  quantities  of  substances,  I  have  been  accus- 
tomed for  a  long  time  to  employ  a  small  still  made  from  a  glue-pot,  and  having  a  copper 
head  made  to  fit  it.  The  lutiiig  for  all  temperatures  not  reaching  above  70°  may  be  a  mix- 
ture of  f  linseed  and  ^  almond  meal,  made  into  a  mass  of  the  consistence  of  putty.  For 
the  apparatus  employed  in  the  destructive  distillation  of  wood,  coal,  btmes,  &c.,  on  the 
large  scale,  the  various  articles  in  this  work  on  the  products  obtained  from  those  substances 
must  be  consulted. 

2.  Desiructire  Distillation  of  Ver/ciable  Matters. — The  principal  vegetable  matters 
which  are  distilled  on  the  l:u-ge  scale  are  wood  and  coal.  We  shall  consider  these  sepa- 
rately. 

JJcsfrvctive  Distillation  of  Wood. — The  products  obtained  in  the  ordinary  process  of 
working,  are  acetic  acid,  wood  spirit  or  methylic  alcohol,  acetone,  pyroxanthine,  xylite,  lig- 
nine,  paraffine,  kreosote,  or  phenic  acid,  oxyphenic  acid,  pittacal,  several  homologues  of 
benzole,  with  ammonia,  and  mcthylamine.  There  are  also  several  other  bodies  of  which 
the  true  nature  is  imperfectly  known.  The  greater  part  of  the  above  substances  are  fully 
described  in  separate  articles  in  this  work.     See  Acetic  Acid,  Pauaffine,  &c. 

Peat  appears  to  yield  products  almost  identical  with  those  from  wood. 

Destructive  Distillation  of  Coal. — The  number  of  substances  yielded  by  the  distillation 
of  coal  is  astonishing.  It  is  very  remarkable  that  the  fluid  hydrocarbons  produced  at  a  low 
temperature  are  very  different  to  those  distilling  when  a  more  powerful  heat  is  employed. 
The  principal  fluid  hydrocarbons  produced  by  the  distillation  and  subsequent  rectification 
of  ordinary  gas  tar  are  benzole  and  its  homologues.  But  if  the  distillate  is  procured  at  as 
low  a  temperature  as  possible,  or  Boghead  coal  be  employed,  the  naphtha  is  lighter,  and  the 
hydrocarl)ons  which  make  its  chief  bulk  belong  to  other  series.     See  Xaphtua. 

3.  Destructive  Distillation  of  Animal  Matters. — Bones  are  the  principal  animal  sub- 
stances distilled  on  the  large  scale.  The  naphthas  which  come  over  are  excessively  fcetid, 
and  are  very  troublesome  to  render  clean  enough  for  use.  The  products  contained  in  bone 
oil  will  be  described  in  the  article  Naphtha.  Horn  and  wool  have  recently  been  examined 
with  reference  to  the  basic  products  yielded  on  distilling  them  with  potash.  Horn  under 
these  circumstances  yields  ammonia  and  amylamine.  Wool  I  find  to  afford  ammonia,  pyr- 
rol, butylamine,  and"  amylamine.  My  experiments  on  feathers,  made  some  years  ago, 
although  not  carried  so  far  as  those  on  wool,  appear  to  indicate  a  very  similar  decompo- 
sition. 

The  products  yielded  by  animal  matters,  when  distilled  pei-  se,  are  very  different  to 
those  obtained  when  a  powerful  alkali  is  added  previous  to  the  application  of  heat.  If 
feathers  or  wool  be  distilled  alone,  a  di.^gustingly  foetid  gas  is  evolved  containing  a  large 
quantity  of  sulphur.  Part  of  the  sulphur  is  in  the  state  of  sulphide  of  carbon.  But  if  an 
alkali  be  added  previous  to  the  distillation,  the  sulphur  is  retained,  and  the  odor  evolved, 
although  powerful,  is  by  no  means  offensive.  During  the  whole  period  of  the  distillation 
of  ordinary  organic  matters  containing  nitrogen,  pyrrol  is  given  off,  and  may  be  recognized 
by  the  reaction  afforded  with  a  slip  of  deal  wood  dipped  in  hydrochloric  acid.  An  interest- 
ing experiment,  showing  the  formation  of  pyrrol  from  animal  matters,  may  at  any  time  be 
made  with  a  lock  of  hair,  or  the  feather  of  a  quill.     For  this  purpose  the  nitrogenous  animai 


DISTILLATION,  DESTRUCTIVE.  465 

matter  is  to  be  placed  at  tlie  bottom  of  a  test  tube,  and  a  little  filtering  paper  is  to  be  placed 
half-way  up  the  tube,  to  prevent  the  water  formed  during  the  experiment  from  returning 
and  fracturing  the  glass.  The  end  of  the  tube  is  now  to  be  cautiously  heated  with  a  spirit 
lamp,  and,  as  soon  as  a  dark  yellowish  smoke  is  copiously  evolved,  a  slip  of  deal  previously 
moistened  with  concentrated  hydrochloric  acid  is  to  be  exposed  to  tlie  vapor.  In  a  few 
seconds  the  wood  will  acquire  a  deep  crimson  color.  The  fact  of  the  presence  of  sulphur  in 
wool,  hair,  or  other  albuminous  compounds  of  that  description,  may  be  made  very  evident 
to  an  audience  by  the  following  experiment: — Dissolve  the  animal  matter  in  very  concen- 
trated solution  of  potash  in  a  silver  or  platinum  basin,  with  the  aid  of  heat.  Evaporate  to 
dryness,  and  raise  the  heat  at  the  end  to  fuse  the  potash  and  destroy  most  of  the  organic 
matters.  When  cold,  dissolve  in  water,  and  filter  into  a  flask  half  full  of  distilled  water. 
To  the  clear  liquid  add  a  little  of  Dr.  Playfair's  nitroprusside  of  sodium  ;  a  magnificent 
purple  tint  will  be  immediately  produced,  indicative  of  the  presence  of  sulphur.  A  very 
small  quantity  of  hair  or  flannel  will  suffice  to  yield  the  reaction. 

The  above  remarks  on  destructive  distillation  apply  principally  to  highly  complex  bodies, 
the  molecular  constitution  of  which  is  either  doubtful,  as  in  the  case  of  albuminous  sub- 
stances, or  totally  unknown,  as  with  coals  and  shales.  The  destructive  distillation  of  organic 
substances  of  comparatively  simple  constitution,  such  as  acids  and  alkalies,  sometimes  yields 
products,  the  relation  of  which  to  the  parent  substance  can  be  clearly  made  out.  This  holds 
more  especially  in  the  case  of  organic  acids ;  the  bases  too  often  yield  such  complex  results, 
that  the  decomposition  cannot  be  expressed  by  an  equation  giving  an  account  of  all  the 
products.     We  shall  study  a  few  cases  separately. 

4.  Destructive  Distillation  of  Acids. — The  destructive  distillation  of  acids  takes  place 
in  a  totally  different  manner,  according  as  we  have  a  base  present  or  the  operation  is  carried 
on  without  any  addition.  Many,  if  distilled  per  se,  undergo  a  very  simple  reaction,  consist- 
ing in  the  elimination  of  carbonic  acid,  and  the  formation  of  a  pi/roacid.  But  if  an  excess 
of  base  be  present,  the  decomposition  often  results  in  the  formation  of  a  ketone,  (see  Ace- 
tone.) We  shall  offer  a  few  examples  of  these  decompositions.  Gallic  acid,  heated  to 
about  419^  Fahr.,  is  decomposed  into  pyrogallic  and  carbonic  acids,  thus: — 
CHjjBQio  _  c'-H'O'  4-  2C0' 

Gallic  acid.  Pyrogallic  acid. 
There  are  cases  in  which  the  action  of  heat  upon  organic  acids  results  in  the  formation 
of  two  substances,  not  produced  simultaneously,  but  in  two  epochs  or  stages.  In  reactions 
like  this,  the  first  effect  is  the  removal  of  two  equivalents  of  carljonic  acid,  and  by  submit- 
ting the  resulting  acid  to  heat  again,  two  more  are  separated.  Under  these  circumstances, 
it  is  the  second  which  is  generally  called  the  pyroacid.  As  an  example  we  will  take  me- 
conic  acid,  which  breaks  up  in  the  manner  seen  in  the  annexed  equations : — 

C'H'O'*  =  C"H'0'»  +  2C0-  C'-H'O'"  =  C'TrO"  +  2C0- 

Meconic  acid.     Comenic  acid.  Comenic  acid.  Pyromeconic  acid. 

It  will  be  seen  that  the  hydrogen  remains  unaffected.  Perhaps  the  name  pyrocomenic 
acid  would  be  preferable  to  pyromeconic  acid,  inasmuch  as  it  is  derived  from  comenic  acid 
in  the  same  manner  as  pyrogallic  from  gallic  acid. 

But  pyroacids  are  not  always  derived  from  the  parent  acid  by  the  mere  elimination  of 
carbonic  acid ;  thus  nuicic  acid,  in  passing  into  pyromucic  acid,  loses  two  equivalents  of 
carbonic  acid,  and  six  equivalents  of  water,  thus : — 

(iijjjioQiG  _  ciojjdoo  ^  2C0^  -f  cno 

Mucicacid.  Pyromucic  acid. 
It  does  not  invariably  happen  that  the  destructive  distillation  of  acids  per  se  results  in 
the  formation  of  a  pyroacid  ;  the  disruption  is  sometimes  more  profound,  the  products  being 
numerous  and  somewhat  complex.  Let  us  take  as  an  illustration  a  case  where  all  the 
results  can  be  reduced  to  an  equation.  Oxalic  acid,  when  heated  in  a  retort  without  addi- 
tion, yields  water,  oxide  of  carbon,  carbonic  and  formic  acids,  in  accordance  witli  the  an- 
nexed equation : — 

4(C=0^^0)  =  4C0=  +  2C0  +  2H0  +  c^iiovio 

Oxalic  acid.  Formic  acid. 

The  admixture  of  sand,  pulverized  pumice  stone,  or  any  other  inert  substance  in  a  state 

of  fine  division,  often  remarkably  assists  in  rendering  the  decomposition  more  easy  and 

definite.     Thus,  if  pure  sand  be  mixed  with  oxalic  acid,  the  quantity  of  formic  acid  is  so 

'  increased,  that  the  process  is  sometimes  employed  in  the  laboratory  as  a  means  of  affording 

a  pure  and  tolerably  strong  acid. 

We  have  said  that  the  destructive  distillation  of  acids  proceeds  in  a  very  different  man- 
ner according  as  we  operate  upon  the  acid  itself,  or  a  salt  of  the  acid.     The  distillation  of 
Vol.  III.— 30 


466 


DISTILLATION,  DESTEUOTIVE. 


the  pure  salt  yields  different  products  to  those  which  are  obtained  when  the  salt  or  dry  acid 
is  mixed  with  a  large  excess  of  a  dry  base,  (such  as  quicklime,)  before  the  application  of 
lunit.  If,  in  the  former  mode  of  proceeding,  two  atoms  of  the  acid  are  decomposed,  yield- 
ing a  body  containing  the  elements  of  two  atoms  of  carbonic  acid  and  two  of  water  less 
than  the  parent  acid,  such  body  is  called  a  ketone.  Thus  when  two  atoms  of  acetate  of 
liine  are  distilled,  the  products  are  one  atom  of  acetone,  and  two  of  carbonic  acid.  Of 
course  the  carbonic  acid  combines  with  the  lime,  thus : — 

2(C'H=CaO')  =  C'H'O^  +  2(CaO,CO=) 

Acetate  of  lime.      Acetone. 
If  Tiowcver,  the  salt  is  not  of  a  very  low  atomic  weight,  and  the  quantities  operated  on 
are  at  all  considerable,  secondary  products  are  formed,  as  in  the  dry  distillation  of  butyrate 
of  lime,  when,  if  the  substance  is  not  in  very  small  quantity,  carbon  is  .deposited,  and  a 
certain  quantity  of  butyral  (CIFO")  is  formed,  and  probably  other  substances. 

As  an  illustration  of  the  decomposition  undergone  when  acids  are  distilled  with  a  great 
excess  of  dry  base,  we  shall  select  that  of  benzoic  acid,  which  under  the  circumstances 
alluded  to  yields  benzole  and  carbonate  of  the  base. 

C'^irO*  =  C"H»  +  2(C0'') 

Benzoic  acid.     Benzole. 

5.  JDestnictive  Distillation  of  Bases. — It  has  been  found  that  the  organic  bases  undergo 
a  much  simpler  and  more  direct  decomposition  when  suVijected  to  destructive  distillation  in 
presence  of  alkalies  than  when  they  are  exposed  to  heat  without  admixture.  There  are  two 
bodies  almost  invariably  found  among  the  resulting  products,  namely,  ammonia  and  pyrrol. 
In  this  respect,  therefore,  the  organic  alkalies  behave  like  other  nitrogenized  animal  and 
vegetable  products.  The  decomposition  is  almost  always  rather  complex,  and  it  is  very 
rare  that  the  products  are  sufficiently  definite  to  be  arranged  in  the  form  of  an  equation. 
The  most  common  substances  found,  are  the  alcohol  bases,  and  these  are  almost  invariably 
of  low  atomic  weight.  One  great  difficulty  connected  with  researches  on  this  subject,  is 
owing  to  the  fact  of  its  being  seldom  that  the  products  are  in  sufficient  quantity  to  enable 
a  thorough  knowledge  of  the  molecular  constitution  to  be  an-ived  at.  Unfortunately  this 
information  is  much  wanted  in  consequence  of  the  numerous  cases  of  isomerism  to  be  met 
with  among  the  alcohol  bases.  See  Formula,  Chemical.  Thus  it  is  difficult,  when  work- 
ing on  very  small  quantities,  to  distinguish  between  bimethylamine  and  ethylamine,  both 
of  which  have  the  formula  CH'N. 

It  is  remarkable  that  there  is  a  great  similarity  between  the  products  of  the  destructive 
distillation  of  some  of  the  most  unlike  nitrogenous  substances.  This  is  conspicuously  seen 
in  the  case  of  bones,  or  rather  the  gelatinous  tissue  of  bones,  shale  and  coal  naphthas,  and 
cinchonine.  An  inspection  of  the  following  table,  compiled  from  a  paper,  (by  the  writer 
of  this  article,)  "  On  some  of  the  Basic  Constituents  of  Coal  Naphtlm,"  will  render  this 
evident. 


Gelatinous  Tissues. 
Pyrrol. 
Pyridine. 
Picoline. 
Lutidine. 
CoUidine. 


Aniline. 


Shale  Narihtha. 
Pyrrol. 
Pyridine. 
Picoline. 
Lutidine. 
CoUidine. 
Parvoline. 


Coal  Xaiihtha. 
Pyrrol. 
Pyridine. 
Picoline. 
Lutidine. 
CoUidine. 

Chinoline. 
Lepidine. 
Cryptidine. 
Aniline. 


Cinchonine. 

Pyrrol. 

Pyridine. 

Picoline. 

Lutidine. 

CoUidine. 

Chinoline. 
Lepidine. 


It  is  very  possible  that  some  of  the  above  bases,  having  the  same  forrnulfc,  but  derived 
from  diffi?rent  sources,  will,  in  the  course  of  time,  prove  to  be  merely  isomeric,  and  not 
absolutely  identical.  The  author  of  this  article  has  quite  recently  found  that  the  chinoline 
of  coal  tar  is  certainly  not  identical  with  that  from  cinchonine.  The  base  from  the  latter 
source  yields  a  magnificent  and  fast  blue  dye  upon  silk,  when  treated  by  a  process  which 
gives  no  reaction  if  the  coal  base  be  substituted.  It  is  unfortunate  that  the  reaction  is  with 
the  latter  instead  of  the  former,  as  it  would  have  added  one  more  to  the  list  of  gorgeous 
dyeing  materials  yielded  by  coal  tar. 

6.  General  Remarks. — The  tendency  of  numerous  researches,  made  during  the  last  few 
years,  has  been  to  show  that  there  is  no  organic  sul)stancp,  capable  of  resisting  high  tem- 
peratures, which  may  not  be  found  to  exist  among  products  of  destructive  distillation.  By 
varying  the  nature  of  the  substance  to  be  distilled,  and  also  the  circumstances  under  which 
the  operation  is  conducted,  we  can  obtain  an  almost  infinite  variety  of  products.  Acids, 
bases,  and  neutral  substances,  solid,  liquid,  and  fluid  hydrocarbons,  organic  positive,  nega- 


DIVING  BELL.  467 

five,  and  derived  radicals,  organo-metallic  bodies, — all  may  be  produced  by  the  action  of 
iiigh  temperatures  on  more  or  less  complicated  bodies.  Much  has  already  been  done,  but 
the  facts  at  present  accumulated  relate  merely  to  the  superficial  and  more  salient  substances. 
On  penetrating  further  below  the  surface,  far  more  valuable  and  interesting  facts  will  come 
to  light.— C.  G.  W. 

DIVING-BELL.  As  it  is  frequently  desirable  to  raise  objects  from  the  bottom  of  the 
sea  or  rivers,  and  to  lay  the  foundation  of  piers  and  similar  structures,  some  contrivance 
was  desired  to  enable  man  to  descend  below  the  water,  and  to  sustain  himself  while  there. 
The  first  method  adopted  was  the  very  simple  one  of  letting  down  a  heavily  weighted  bell 
vertically  into  the  water.  As  the  bell  descended,  the  air  got  overpressed,  and  the  water 
rose  in  the  bell,  but  never  to  the  top,  and  within  that  space  the  man  was  sustained  for  some 
time.  The  air,  however,  was  vitiated  by  the  processes  of  respiration,  and  the  man  had  to 
be  drawn  up.  It  is  curious  to  find  that  as  early  as  1693  a  very  complete  system  of  diving 
without  a  bell  was  devised,  as  the  following  quotation  will  show  : — 

A.  D.  1693.  "  William  and  Mary,  by  the  Grace,  &c.  &c.  Whereas  John  Stapleton, 
gentleman,  hath  by  his  great  study  and  expence  invented  a  new  and  extraordinary  engine 
of  copper,  iron,  or  other  mettal,  with  glasses  for  light  joints,  and  so  contrived  as  to  permit 
a  person  enclosed  to  move  and  walk  freely  with  under  water,  and  yet  so  closely  covered 
over  with  leather  as  sufficiently  to  defend  him  from  all  the  jumpes  of  it.  Also  invented  a 
way  to  force  air  into  any  depth  of  water,  whereby  the  person  in  the  aforesaid  engine  may 
bo  supplied  with  a  continual  current  of  fresh  aire,  which  not  only  serves  him  for  respi- 
ration, but  may  ahoe  be  useful  for  continuing  a  lamp  burning  which  he  mag  carry^  about 
with  him  in  his  hand.  *  »  *  Likewise  a  way  to  make  the  same  again  ser- 
viceable for  respiration,  and  by  continually  repeating  the  operation,  a  man  may  remain  a 
long  time  under  water,  in  either  of  the  sayd  engines,  without  any  other  air  than  thesayd 
engines  do  contayne,  whereby  he  shall  be  preserved  from  suffocation,  if  any  extraordinary 
accident  should  "interrupt  the  current  of  fresh  air  afore  mentioned." — Letters  Patent. 
Rolls  (Jhapel.     Edited  by  Bennct  Woodcraft. 

The  defects  were  many  in  this  apparatus,  and  Dr.  Halley  invented  a  bell  the  object  of 
which  was  to  remedy  them. 

Dr.  Halley's  bell  was  of  wood  coated  with  lead,  and  having  strong  glass  windows  above, 
to  allow  the  passage  of  light  to  the  diver.  In  order  to  supply  air,  a  barrel  was  taken  with 
an  open  hole  in  the  bottom,  and  a  weighted  hose  hanging  by,  and  fitting  into  a  hole  at  the 
top.  From  this  barrel  the  air  of  the  bell  was  supplied  as  frequently  as  it  became  vitiated, 
the  barrels  of  air  being  sent  down  from  above.  Spalding  improved  upon  Halley's  bell,  and 
again  Friewald  made  some  improvements  on  Spalding's,  but  in  principle  these  bells  were  all 
alike.  The  modern  bells  are  usually  large  and  strong  iron  bells,  with  windows  in  the  upper 
part.  By  means  of  an  air-pump,  placed  on  the  surface,  air  is  sent  down  to  the  divers  in  the 
bell,  and  the  vitiated  air  is  as  regularly  removed  from  the  bell  by  other  tubes  through  which 
it  escapes.  These  diving-bells  are  lowered  by  means  of  cranes,  and  are  moved  about  in  the 
water  by  those  above,  signals  being  given  by  the  men  below.  The  difficulty  of  moving  this 
machine  renders  it  still  inconvenient,  and  recent  attempts  have  been  made  to  obviate  this, 
by  the  construction  of  a  diving-bell  upon  principles  entirely  different.  This  new  diving- 
bell,  to  which  the  name  of  The  Nautilus  has  been  applied,  has  proved  so  useful  in  the  con- 
struction of  some  parts  of  the  Victoria  Docks,  and  some  works  on  the  Seine,  that  a  full 
description  of  it  is  appended. 

The  nautilus  machine  is  entirely  independent  of  suspension  ;  its  movements  are  entirely 
dependent  on  the  will  of  those  within  it,  and  without  reference  to  those  who  may  be  sta- 
tioned without ;  it  possesses  the  power  of  lifting  large  weights,  per  se,  and  at  the  same  time 
is  perfectly  safe,  by  common  care  in  its  operations.  This  latter  is  the  greatest  desideratum 
of  all.  These  advantages  must  strike  all  as  combining  those  requisites  of  success  which 
have  been  always  wanting  in  the  present  known  means  for  constructing  works  under  water. 

The  form  of  the  machine  is  not  arliitrary,  but  depends  entirely  on  the  nature  of  the 
work  to  be  performed,  adapting  itself  to  the  various  circumstances  attending  any  given 
position.  By  reference  to  the  annexed  figures,  it  will  be  perceived  that  when  at  rest,  being 
entirely  enclosed,  its  displacement  of  water  being  greater  than  its  own  weiglit,  it  must  float 
to  the  surface,  (see  fg.  211.)  Entering  through  a  man-hole  at  the  top,  (which  is  closecl 
either  from  the  inside  or  outside,)  you  descend  into  the  interior  of  the  machine,  portions  of 
which  are  walled  off  on  either  side,  forming  chambers  ;  these  chambers  are  connected  at  or 
near  the  bottom  of  a  pipe  a  a,  which  opens  by  a  cock  b,  outwards  to  the  external  surround- 
ing water.  An  opening  in  tlie  l)ottom  of  the  machine  of  variable  dimensions  is  closed  by 
a  door  or  doors  susceptible  of  being  opened  or  closed  at  pleasure.  The  chambers  w  w  are 
likewise  connected  at  top  by  a  smaller  pipe  c  c,  which  opens  through  the  top  of  the  nia- 
cliine,  and  to  which  opening  is  affixed  a  Hexible  pipe,  with  coils  of  wire  spirally  enclosed. 
Branches  on  this  latter  pijjc  t  allow  also  communication  with  the  larger  or  workmg 
chamber. 

At  the  surface  of  the  water  placed  on  a  float  or  vessel  for  the  purpose,  is  a  receiver  of 


468 


DIVING  BELL. 


variable  dimensions,  to  which  is  attached  at  one  end  a  hollow  drum  or  reel,  to  the  barrel  ol 
which  is  affixed  the  other  end  of  the  flexible  pipe  a,  leading  to  the  top  of  the  nautilus.  At 
the  other  end  of,  and  in  connection  with  the  receiver,  is  a  powerful  air-condensing  pump. 
Tliis  combination  represents  the  nautilus  as  adapted  to  engineering  work. 


•->41 


As  to  the  modus  operandi : — The  operator  with  his  assistants  enters  the  machine  through 
the  top,  which  is  then  closed.  To  descend,  the  water-cock  b  is  opened,  and  the  external 
water  flows  into  the  chambers  w  w  ;  at  the  same  time  a  cock,  on  a  pipe  opening  from  the 
chambers  outwards,  is  opened,  in  order  that,  the  air  escaping,  an  uninterrupted  flow  of 
water  may  take  place  into  the  chambers.  The  weight  of  water  entering  the  chambers 
causes  a  destruction  of  the  buoj'ancy  of  the  machine,  and  the  nautilus  gradually  sinks.  As 
soon  as  it  is  fairly  under  water,  in  order  that  the  descent  may  be  quiet  and  without  shock, 
the  water-cock  b  is  closed.  The  receiver  at  the  surface  being  previously  charged  by  the  air- 
pump  to  a  density  somewhat  greater  than  that  of  the  water  at  the  depth  proposed  to  attain, 


one  of  the  l)ranch  cocks  on  tlie  i)iiie  <■  <;  connecting  the  chambers  at  top,  is  opened,  and  the 
air  rushes  into  the  working  chaml)er,  gradually  condensing  until  a  density  equal  to  the  den- 
sity of  the  water  without  is  attained ;  this  is  indicated  by  proper  air  and  water  gauges. 


DIVING  BELL. 


469 


These  gauges  marking  equal  points,  showing  the  equilibrium  of  forces  without  and  within, 
the  cover  to  the  bottom  z  is  removed  or  raised,  and  commuuicatiou  is  made  with  the  under- 
water surface,  on  which  the  nautilus  is  resting.  In  order  to  move  about  iu  localities  where 
tides  or  currents  do  not  affect  operations,  it  is  only  necessary  for  the  workmau  to  step  out 
of  the  bottom  of  the  nautilus,  and  placing  the  hands  against  its  sides,  the  operator  may 
move  it  (by  pushing)  in  any  direction. 

Where  currents  or  tides,  however,  have  sway,  it  becomes  necessary  to  depend  upon  fixed 
points  from  which  movements  may  be  made  in  any  direction.  Tliis  is  accomplished  by 
placing,  in  the  bottom  of  the  nautilus,  stuffing-boxes  of  peculiar  construction,  (m  m,  fiy. 
242,)  through  which  cables  may  pass  over  pulleys  to  the  external  sides,  thence  up  through 
tubes,  (to  prevent  their  being  worn,)  to  and  over  oscillating  or  swinging  pulleys,  placed  in 
the  plane  of  the  centre  of  gravity  of  the  nautilus,  and  thence  to  the  points  of  affixmcnt 
respectively,  {fig.  243.)     The  object  to  be  gained  by  having  the  swinging  pulleys  in  the 


plane  of  the  centre  of  gravity  of  tlie  mass,  is  to  hold  the  machine  steady  and  to  prevent 
oscillation.  Within  the  maciiine,  and  directly  over  the  above  stuffing-boxes,  are  windlasses 
for  winding  in  the  cables.  By  working  these  windlasses  movement  may  be  effected,  and  of 
course  the  number  of  these  cables  will  depend  on  the  variable  character  of  the  situation  to 
be  occupied.  Having  thus  secured  the  means  of  descending,  communicating  with  the  bot- 
tom, and  of  movement,  the  next  point  is  to  ascend.  Weight  of  water  has  caused  a  destruc- 
tion of  buoyancy  at  first,  and  consequent  sinking ;  if,  then,  any  portion  of  this  water  is 
removed,  an  upward  effort  will  at  once  be  exerted  exactly  proportionate  to  the  weight  of 
water  thrown  off.  The  air  in  the  receiver  at  the  surface  being  constantly  maintained  at  a 
higher  density  than  that  of  the  water  below,  if  we  open  the  water-cock  on  the  top  pipe  c  c, 
throwing  the  condensed  air  from  the  receiver  above  directly  on  to  the  surf^ace  of  the  water 
in  the  chambers,  movement  and  consequent  expulsion  of  the  water  must  take  place,  and  an 
upward  movement  of  the  machine  itself,  which  will  rise  to  the  surface. 

It  is  evident  that  if,  previously  to  the  expulsion  of  the  water,  the  nautilus  be  affixed  to 
any  object  below,  the  power  exerted  on  that  object  will  be  exactly  proportionate  to  tlie 
weight  of  water  expelled,  and  the  power  will  continue  increasing,  until,  there  being  no  f\ir- 
ther  weight  to  be  thrown  off,  the  maximum  effect  is  produced.  To  apply  this  power  to  lift- 
ing masses  of  stone  or  rock,  proper  arrangements  are  affixed  to  tlie  centre  of  the  opening 
in  the  bottom,  by  which  connection  can  be  made  with  tlie  weight,  admitting,  at  the  same 
time,  the  swinging  around  of  the  oliject  suspended,  so  that  it  may  be  placed  in  any  required 
position.  In  the  construction  of  permanent  work,  or  the  movement  of  objects  whose  weight 
is  known,  or  can  be  estimated,  a  water,  or  so-called  lifting  tube,  is  placed  on  the  side  of 
the  water  chamber,  which  indicates  the  lifting  power  exercised  by  the  nautilus  at  any  mo- 
ment. The  advantage  of  tliis  gauge  will  be  recognized,  inasmuch  as  without  it  the  closest 
attention  of  the  operator,  working  very  cautiously,  woukl  be  necessary  to  determine  when 
the  weight  was  overcome ;  by  its  aid,  however,  the  operator  boldly  throws  open  all  the 
v, lives  necessary  to  develop  the  power  of  the  nautilus,  watching  only  the  gauge.  The  water, 
having  reached  the  proi)cr  level  indicating  the  required  lifting  power,  he  knows  the  weight 
must  be  overcome,  or  so  nearly  so  that  the  valve  or  cocks  may  be  at  once  closed,  in  order 
that  the  movement  may  take  place  horizontally.     A  moment's  reflection  will  show  that,  if 


470 


DIVING  BELL. 


there  were  not  an  index  of  this  character,  carelessness  or  inattention  on  the  part  of  the 
operator,  by  leaving  the  cocks  open  too  long,  might  develop  a  power  greater  than  required, 
and  the  nautilus  would  start  suddenly  upward.  The  expansive  power  of  air,  acting  upon 
the  incompressible  fluid,  water,  through  the  opening  in  the  bottom,  gives  a  momentum 
which,  by  successive  developments  of  expansion  in  the  working  chamber,  is  constantly 
increasing  in  velocity,  until,  in  any  considerable  depth  of  water,  the  result  would  be  un- 
doubtedly of  a  very  serious  character.  Take,  for  exemplification,  the  nautilus  in  thirty- 
three  feet  of  water,  and  bottom  covers  removed,  and  an  equilibrium,  at  fifteen  pounds  to 
the  inch,  existing  between  the  air  and  the  water  at  the  level  of  the  bottom  of  the  machine. 
Upward  movement  is  communicated  the  instant  the  machine  rises  in  the  slightest  degree, 
the  existing  equilibrium  is  destroyed,  and  the  highly  elastic  qualities  of  air  assume  prepon- 
derance, exerting,  from  the  rigid  surface  of  the  water  below,  an  impulsive  effort  upward  in 
the  direction  of  least  resistance.  At  each  successive  moment  of  upward  movement  the 
impelling  power  increases,  owing  to  the  increasing  disparity  between  the  pressure  of  air 
within  struggling  for  escape.  Tlie  machine,  thus  situated,  becomes  a  marine  rocket,  (in 
reality,)  in  which  the  propelling  power  is  exhausted  only  when  the  surface  is  reached,  and  a 
new  equilibrium  is  obtained.  It  will  readily  be  seen  that,  were  this  difficulty  not  overcome, 
it  would  be  impossible  to  govern  the  nautilus;  for,  rising  with  great  velocity  to  the  surface, 
the  machine  is  carried  above  its  ordinary  flotation,  or  water  line,  a  little  more  air  escaping 
owing  to  the  diminished  resistance  as  that  level  is  passed  ;  the  recoil,  or  surging  downwards, 
causes  a  condensation  of  the  air  remaining  in  the  chamber ;  a  portion  of  the  space  pre- 
viously occupied  by  air  is  assumed  by  water ;  the  buoyant  power  becomes  less,  the  machine 
settles  slightly  more  by  condensation  of  the  air,  a  larger  space  is  occupied  by  water,  and 
the  nautilus  redescends  to  the  bottom  with  a  constantly  accelerating  movement,  seriously 
inconveniencing  the  operator  by  filling  more  or  less  with  water,  according  to  depth.  For 
many  months  the  difficulties  just  enumerated  baffled  all  attempts  at  control.  A  weight 
attached  could  be  lifted,  but  the  instant  it  was  entirely  suspended, — before  the  valves  could 
b(!  closed, — upward  movement  was  communicated  beyond  control.  This  difficulty,  so  fatal, 
li:is  been  overcome  by  an  arrangement  at  the  bottom  of  the  nautilus,  with  channels  which 
radiate  from  the  opening  in  an  inclined  direction,  debouching  at  the  sides  of  the  machine. 
T'.ie  moment,  then,  that  the  air,  by  its  expansion  from  diminished  resistance,  or  by  the 
iiitroduction  from  above  of  a  greater  volume  than  can  be  sustained  by  the  water  below, 
reaches,  in  its  do^^^lward  passage,  the  level  of  these  chambers,  following  the  direction  of 

244 


DIVING  BELL. 


471 


least  resistance,  it  passes  througli  these  channels  and  escapes  into  the  surrounding  Tcatcr, 
without  of  course  aftecting  the  movement  of  the  machine  in  the  least. 

The  pump  for  supplying  air  to  the  diving-bell  or  other  suitable  vessel,  is  represented  at 
figs.  244  and  245,  and  is  constructed  as  follows : — d  is  a  cylinder,  opening  at  the  upper 
part  into  a  chamber  or  chambers  f  f,  separated  by  a  partition  e.  On  the  side  of  each  of 
these  chambers  there  is  a  valve  h  h,  opening  inwards,  and  at  the  upper  part  of  the  same 
are  two  valves  i  i,  opening  outwards  into  the  valve  chamber  g.  Outside  the  opening  for 
each  of  the  valves  ii  u,  there  is  a  cup,  into  which  the  end  of  the  water  supply  pipe  m  passes ; 
by  this  means  a  small  stream  of  water  is  supplied  to  the  cup,  and  is  drawn  frc^n  it  into  the 
chamber  f  to  supply  the  waste  in  the  operation  of  pumping.  The  valve  chamber  g  is  cov- 
ered with  a  jacket  k,  having  a  space  between  it  and  the  valve  chamber  that  is  filled  with 
water  from  the  water  pipe  m,  which  affords  a  stream  of  cold  water  to  carry  off  the  heat  from 
the  condensed  air  which  is  forced  into  the  chamber.  The  water  thus  supplied  circulates 
through  the  tubes  in  the  chamber  and  round  them  in  the  jacket,  and  thus  cools  the  air  in 
these  tubes ;  it  is  then  conveyed  so  as  to  be  usefully  employed  in  a  steam-boiler,  or  is 
allowed  to  run  off.  The  air  and  a  small  quantity  of  water  is  forced  up  from  the  cylinder  d 
by  the  stroke  of  the  piston  c  into  the  chamber  f,  which  is  thereby  filled  with  water,  and 
thus  the  air  is  expelled  therefrom,  a  small  quantity  of  the  water  passing  with  it  and  cover- 
ing the  valves,  by  which  means  they  are  kept  tight  and  wet.  The  air  and  water  thus  dis- 
charged, after  passing  around  the  small  tubes  in  the  valve  chamber  and  being  cooled,  are 
forced  outward  and  conveyed  to  the  condenser.  On  the  return  stroke  of  the  piston,  the 
other  chamber  f  is  filled,  and  air  and  water  expelled  from  it  in  like  manner  through  its 
valve  into  the  valve  chamber.  There  is  always  a  sufficient  quantity  of  water  in  the  cylin- 
der D  and  chamber  f  to  fill  the  latter  when  the  water  is  all  expelled  from  the  cylinder,  by 
the  piston  c  having  been  driven  to  one  end  of  it,  and  when  the  piston  returns  to  the  oppo- 
site end  of  the  cylinder,  the  water  flows  in  b'ehind  it,  and  draws  in  its  equivalent  in  bulk 
of  air  and  water  through  the  valve  h.  On  its  return,  this  is  forced  out  through  the  valve  k 
into  the  chamber  i,  as  mentioned  above.  The  water  being  non-elastic,  if  the  parts  are  kept 
cool  enough  to  avoid  raising  steam,  this  process  may  be  continued  for  any  length  of  time. 
A  transverse  section  of  this  apparatus  is  shown  in  fig.  245. 


Figs.  240  and  247  represent  the  speaking-tube  and  alarm-bell  above  referred  to.  The 
construction  of  this  mechanism  is  as  follows: — There  is  a  hollow  casting,  one  portion  of 
which  is  triangular  in  form,  from  one  end  of  which  a  short  tube  a  projects.  This  tube  a 
has  a  screw  cut  on  it,  and  a  projecting  flange  at  its  junction  with  the  triangle.  This  is 
screwed  into  the  top  of  the  diving  vessel  or  armor  from  the  inside,  and  projects  through 


472 


DIVIXG  BELL. 


it  to  allow  the  coupling  of  a  flexible  or  other  hose  to  be  attached  to  it.  At  the  opposite 
angle,  and  in  a  line  with  a,  there  is  a  tubular  projection  h,  provided  with  a  screw  to  receive 
a  cap  /,  to  which  is  to  be  attached  a  piece  of  hose.  Within  the  tube  /,  and  at  its  junction 
witii  6,  is  placed  a  thin  diaphragm  of  metal  or  other  suitable  material  c,  for  which  purpose, 
however,  a  thin  silver  plate  that  just  fits  the  bore  of  the  cap  /"  is  preferred.  This  diaphragm 
closes  all  communication  between  the  diving  vessel  and  the  external  air.  By  this  means  ii 
is  easy  to  converse  through  any  required  length  of  tuljing.  It  may  be  desirable  to  fit  a 
stop-cock  into  the  tubular  projection  b,  as  a  precautionary  means  of  preventing  the  escape 
of  air  in  the»event  of  a  rupture  of  the  diaphragm.  The  upper  part  of  the  triangular  en- 
largement of  the  speaking-tube  is  tapped  for  a  stuffing-box  at  a,  within  which  tliere  is  an 
axis  /?,  which  runs  from  side  to  side  of  the  said  enlargement,  and  through  tl;e  stiiHing-box 
at  one  side.  On  this  axis  //  is  fixed  a  lever  i  within  the  said  enlargement,  which  lever  com- 
municates with  the  surface  of  the  water  by  means  of  a  wire  fixed  at  its  reversed  end,  and 
running  through  the  whole  length  of  pipe.  On  the  outer  extremity  of  the  axis  //  is  affixed 
a  hammer,  which  strikes  on  a  bell  k  connected  to  the  tube,  as  shown  in  the  drawing.  By 
this  means  the  attention  of  the  operator  below  may  be  drawn  to  the  speaking-tube  when  it 
is  required  to  converse  with  him  from  the  surface  of  the  water,  and  the  men  whose  duty  it 
is  to  attend  to  the  operator  below  can,  by  placing  their  ear  at  the  end  of  the  tube,  hear  the 
bell  struck  below  as  a  signal  for  communication  with  them  at  the  surface. 

The  only  parts  of  the  apparatus  not  yet  described,  are  the  saw  for  cutting  the  tops  of 
piles  to  an  uniform  level,  the  pump  which  enables  the  divers  themselves  to  rise  to  the  sur- 
face in  the  event  of  the  flexible  hose  being  detached  or  injured,  and  the  contrivance  for 
screwing  an  eye-bolt  into  the  side  of  the  sunken  vessels. 

The  arrangement  of  the  saw-frame 
24S  and  connections  are  shown  in  p'g.  248. 

Only  as  much  of  the  bottom  of  the  nau- 
tilus is  shown  as  will  render  the  position 
of  the  saw  understood.  p  is  a  pile 
which  is  required  to  be  cut  down  to  the 
same  level  as  the  others ;  e  is  the  blade 
of  the  saw  ;  d  the  framing  by  which  it 
is  stretched ;  c,  n,  the  handle  which  rests 
on  the  cross-bar  k  ;  to  which  is  attached 
the  upright  part  of  the  handle  which  is 
laid  hold  of  by  the  workman  inside  when 
woiking  the  saw.  h,  g,  f,  a  bent  lever 
with  two  friction  rollers  at  f  winch 
guides  the  saw  forwards  while  making 
the  cut. 

The  pump  for  ascending  in  case  of 
accident  to  the  air-hose,  is  not  shown  in 
the  drawing.  It  is  a  simple  force-pump 
placed  in  the  working  chamber,  by  which 
the  ballast  water  in  w  w,  (fie/.  242,)  can 
be  pumped  out  so  as  to  lighten  the  ap- 
paratus sufficiently  to  allow  of  its  ascent. 
The  apparattts  for  fixing  the  eye-bolts 
is  shown  in  _/%/.  249.  The  operation  of 
this  apparatus  is  as  follows  : — It  will  be 
observed  the  chamber  d  opens  outwards 
to  the  water,  so  that  when  the  sliding 
partition  or  valve  ;/  is  forced  down  by 
the  lever  </,  the  corr.munication  of  the 
water  with  the  chamber  c  is  cut  off. 
The  lid  z  being  removed,  a  bolt  i  (or 
other  operating  tool  or  instrument)  is 
placed  within  the  chamber  c  ;  the  rod  ^• 
is  forced  through  the  stuffing-box  /,  until 
the  recessed  end  of  the  rod  contains  the 
end  of  the  bolt ;  the  small  rodj  is  then 
screwed  through  the  stuffing-box  v,  until 
the  screw  on  the  end  of  this  rod  has  be- 
come affixed  to  the  end  of  the  bolt  con- 
tained within  the  recess  at  p.  The  lid 
2  of  the  chest  is  then  fastened  on,  and 
the  partition  or  valve  7/  raised,  the  stuffing-box  m  preventing  the  escape  of  air.  Commimi- 
cation  is  thus  opened  between  the  chambers  a  and  n,  the  latter  being  open  outwards.     The 


DEY  GPwINDING.  473 

rod  i  is  now  pushed  outwards  by  pressing  on  the  handle  k  through  the  stufSng-box  Z,  until 
the  vessel  or  object  to  be  operated  upon  is  reached,  when  the  operation  is  performed  as 
required.  It  will  be  observed  that  the  stufHng-box  prevents  the  escape  of  air  out  of  the  bell 
or  the  admission  of  water  into  it,  the  stutting-box  ?j  having  the  same  tendency.  Alter*  the 
operation  with  the  tool  or  instrument  is  complete,  the  rod  /:  is  disconnected  by  unscrewing 
the  rod /,  and  is  drawn  into  the  chamber  a  l)y  means  of  the  handle  k  ;  the  partition  or  valve 
//  is  again  lowered,  and  the  operations  above  described  are  rci>eated.  It  will  hence  be  ob- 
vious that  a  number  of  eye-bolts  might  in  tliis  manner  be  successfully  inserted  in  the  side  of 
a  sunken  vessel  from  the  diving-bell,  so  that  by  hooking  on  the  "  camels,"  the  strain  would 
be  so  distributed  as  to  prevent  injury  by  the  process  of  lifting  the  said  vessel. 

DOLO.MITE.  Magnesian  Limestone.  This  rock  occurs  in  very  great  abundance  in 
various  parts  of  England,  especially  in  Yorkshire,  Nottinghamshire,  and  Somerset.  It  is 
largely  employed  as  a  building  stone. 

Karsten  infers,  from  his  numerous  analyses  of  dolomite,  that  in  those  which  are  crystal- 
lized, the  carbonate  of  lime  is  always  combined  in  simple  equivalent  proportion  with  an- 
other carbonate,  which  may  be  carbonate  of  magnesia  alone,  or  together  with  carbonates 
of  iron  or  manganese,  and  sometimes  both.  In  the  uncrystallized  varieties  of  dolomite,  the 
diversity  in  the  proportion  of  lime  and  magnesia  is  indetinite,  but  such  ma.^ses  must  be  re- 
garded as  mere  mixtures  of  true  dolomite  and  carbonate  of  lime.  Acids  do  not  produce  a 
perceptible  eftervescence  with  dolomite,  except  when  digested  whh  it  in  fine  powder. 
Karsten  found  that  dilute  acetic  acid  extracts  from  dolomites,  at  a  temperature  below  32' 
Fahr.,  only  carbonate  of  lime,  while  a  dolomitic  mass  remains  undissolved.  Hence  he  re- 
gards them  as  mixtures  of  dolomite  with  unaltered  carboiuite  of  lime. — Bischof. 

Sulphate  of  magncaia  has  been  manufactured  from  dolomite  on  the  large  scale. 

Dr.  William  Henry,  of  Manchester,  patented  a  process  of  the  following  kind  : — Calcine 
magnesian  limestone  so  as  to  expel  the  carbonic  acid ;  then  convert  the  caustic  lime  and 
magnesia  into  hydrates  by  moistening  them  with  water ;  afterwards  add  a  sufficient  quan- 
tity of  hydrochloric,  nitric,  or  acetic  acid,  or  chlorine  to  dissolve  the  lime,  but  not  the  mag- 
nesia, which,  after  being  washed,  is  converted  into  sulphate  by  sulphuric  acid,  or,  where 
the  cost  is  objectionable,  by  sulphate  of  iron,  which  is  easily  decomposed  by  magnesia.  Or 
the  mixed  hydrates  of  lime  and  magnesia  are  to  be  added  to  bittern :  chloride  of  calcium 
is  formed  in  solution,  while  two  portions  of  magnesia  (one  from  the  bittern,  the  other  from 
the  magnesian  lime)  are  left  unacted  on.  Hydrochloratc  of  ammonia  may  be  used  instead 
of  bittern :  by  the  reaction  of  this  on  the  hydrated  magnesian  lime,  chloride  of  calcium  and 
caustic  ammonia  remain  in  solution,  while  magnesia  is  left  undissolved ;  the  ammonia  is 
separated  from  the  decanted  liquor  by  distillation. 

In  some  chemical  works  on  the  Tyne,  the  dolomites  from  the  coast  around  Marsden  are 
treated  with  sulphuric  acid,  and  the  sulphate  of  magnesia  {Epwm  salts)  separated  from  the 
sulphate  of  lime  by  crystallization. 

The  dolomite  has  also  been  employed  by  the  late  Hugh  Lee  Pattinson  for  the  manufac- 
ture of  the  Carbonate  of  Magnesia. 

DOWN.     See  Feathers.     Down  imported  in  1857,  5,208  lbs. 

DRAGON'S  BLOOD.  Pereira  enumerate:^ he  following  varieties  of  this  substance  found 
in  commerce : — 

1.  Dragon^s  blood  in  the  reed ;  DragorCs  blood  in  sticks ;  Sanguis  Draconis  in 
baculis. 

2.  DragorCs  blood  in  oval  masses ;  Dragon^s  blood  in  drops ;  Sanguis  Draconis  in 
lachrymis. 

3.  Dragon's  blood  in  powder. 

4.  Dragon^ s  blood  in  the  tear  ;  Sanguis  Draconis  in  granis. 

5.  Lrimp  Dragon'' s  blood  ;  Sanguis  Draconis  in  massis. 

Besides  these,  there  are  Dragori's  blood  in  cakes,  and  False  Dragonh  blood,  in  oval 
masses. 

DRAINING  TILES.  Burnt-clay  tiles,  generally  shaped  in  section  like  a  horse  shoe, 
about  one  foot  long  and  two  or  three  inches  broad.  These  are  much  used  in  agricultural 
draining. 

DRY  GRINDING.  The  practice  of  employing  dry  stones  has  been  long  adojited 
for  the  purpose  of  quickening  the  processes  of  .sharpening  and  polishing  steel  goods. 
The  dry  dust  from  the  sand-stone,  mixed  with  the  fine  particles  of  steel,  being  inhaled 
by  the  workmen,  produces  diseases  of  the  pulmonary  organs  to  such  an  extent,  that 
needle  and  fork  grinders  are  reported  rarely  to  live  beyond  the  ages  of  twenty-five  or 
thirty. 

Mr.  Abraham,  of  Sheffield,  first  invented  magnetic  guards,  which,  being  placed  close  to 
the  grindstone,  attracted  the  particles  of  steel,  and  thus  protected  the  men  from  their  influ- 
ences. Still  they  suffered  from  the  cfTccts  of  the  fine  sand-dust,  and  the  grinders  heedlessly 
abandoned  the  use  of  them  altogether. 

Mr.  Abraham  devised  another  plan,  which  is  employed,  although  only  partially,  in  the 


474  DULSE. 

Sheffield  works.  The  grindstone  is  enclosed  in  a  wooden  case,  which  only  exposes  a  por- 
tion of  the  edge  of  the  stone  ;  a  horizontal  tube  proceeds  as  a  tangent  from  the  upper  sur- 
face of  the  circle  to  the  external  atmosphere.  The  current  of  air  generated  by  the  stone  in 
rapid  revolution,  escaping  through  the  tube,  carries  off  with  it  nearly  all  the  dust  arising 
from  the  process.  It  is  curious  to  find  so  simple  a  contrivance  frequently  rejected  by  the 
workmen,  notwithstanding  that  sad  experience  teaches  them,  that  they  are  thereby  expos- 
ing themselves  to  the  iufiuences  of  an  atmosphere  which  produces  slowly  but  surely  their 
dissolution. 

DULSE.     The  Rhodomenia  palmata.     See  Alce. 

DUNES.  Low  hills  of  blown  sand,  which  arc  seen  on  the  coasts  of  Cheshire  and 
Cornwall,  in  this  country,  and  also  in  many  places  skirting  the  shores  of  Holland  and 
Spain. 

DUTCH  LEAF  or  FOIL,  a  composition  of  copper  and  lime,  or  of  bronze  and  copjier 
leaf.     See  Alloys,  Bkass,  and  Bronze  Powdkks. 

DUTCU  RUSH.  Eipdsdum  Hyemalc.  This  rush  is  known  also  as  the  Large  hranch- 
less  Horse-tail.  The  dried  stems  are  much  employed  for  polishing  wood  and  metal.  For 
this  purpose  they  are  generally  imported  from  Holland. 

DYEING.  The  relations  of  dyeing  with  the  principles  of  chemistry,  constitute  the 
theory  of  the  art,  properly  speaking  ;  tlii^  theory  has  for  its  basis  the  knowledge — 

1st.  Of  the  nature  and  properties  of  the  bodies  which  dyeing  processes  bring  into 
contact. 

2d.  Of  the  circiunstances  in  which  these  bodies  are  brought  together,  faciUtating  or  re- 
tarding their  action. 

3d.  The  phenomena  which  appear  during  their  action  ;  and 

4th.  Properties  of  the  colored  combinations  which  are  produced. 

The  fii-st  of  these  generalities  embraces  a  knowledge  of  the  preparations  which  stuff  ne- 
cessarily undergoes  previous  to  dyeing,  and  also  the  preparations  of  the  dye-drug  before 
bringing  it  into  contact  with  the  stuff'. 

The  operations  to  which  stuffs  are  subjected  before  dyeing,  are  intended  to  separate 
from  them  any  foreign  matters  which  may  have  become  attached,  or  are  naturally  inherent 
in  the  stuff.  The  former  are  such  as  have  been  added  in  the  spinning,  weaving,  or  other 
manipulations  of  the  manufacture,  and  are  all  removed  by  steeping  in  an  alkaline  lye  and 
washing.  The  second  are  the  natural  yellow  coloring  substances  which  coat  some  of  the 
various  fibres,  both  vegetable  and  animal ;  and  the  chlorophylle,  or  Jeaf-green  of  vegetables. 
The  removal  of  these  is  generally  effected  by  boiling  in  soap  and  alkaline  lyes.  A  weak 
bath  of  soda,  in  which  the  stuff  is  allowed  to  steep  for  some  time,  and  then  washed  in 
water,  is  generally  the  only  preparation  required  for  wool,  in  order  that  it  may  take  on  a 
uniform  dye. 

To  remove  the  gummy  or  resinous  matter  from  silk,  it  requires  boiUng  in  soap  lye ; 
however,  its  removal  is  not  essential  to  the  stuff  combining  with  the  dye,  as  silk  is  often 
dyed  while  the  gum  remains  in  it,  in  which  case  it  is  only  rinsed  in  soap  lye  at  a  very  mod- 
erate heat,  to  remove  any  foreign  matters  imbibed  in  the  process  of  manufacture. 

Vegetable  fibre,  as  cotton,  has  such  natural  resinous  matters  that  retard  the  reception 
of  the  dye  removed  by  boiling,  either  with  or  without  alkaline  lyes ;  but  the  natural  dun 
color  of  the  fibre  is  not  removed,  which  from  the  laws  of  light  and  color  already  referred  to, 
would  interfere  with  the  production  of  bright  light  tints ;  under  these  circumstances,  the 
natural  color  of  the  fibre  has  to  be  previously  removed  by  bleaching,  for  which  see  the  ar- 
ticle, Bleaching. 

The  necessary  preparation  of  the  dye-drugs  within  the  province  of  the  dyer,  is  to  obtain 
the  color  in  a  state  of  solution,  so  as  to  allow  the  fibre  to  absorb  it,  and  to  produce  chem- 
ical combination,  or  to  get  the  dye  or  color  in  such  a  minute  state  of  division  as  it  will 
penetrate  or  enter  into  the  filjre  of  the  stuff.  These  preparations  embrace  the  formation  of 
decoctions,  extracts,  and  solutions,  and  also  in  some  cases  of  precipitation,  previous  to  im- 
mersing the  stuff"  into  the  bath.  Stuff's,  chemically  considered,  have  but  a  feeble  attraction 
for  other  matters,  so  as  to  combine  with  them  chemically ;  still,  that  they  do  possess  certain 
attractions  is  evident  from  various  phenomena  observed  in  the  dyeing  processes,  and  that 
this  attraction  is  possessed  with  different  degrees  of  intensity  by  the  different  fibres,  is  also 
evident  from  the  ease  and  permanence  that  woollen  stuff'  will  take  up  and  retain  dyes  com- 
pared with  cotton ;  and  also,  that  certain  dj'cs  are  retained  and  fixed  within  or  upon  one 
kind  of  fibre  and  not  at  all  in  another.  This  may  be  determined  by  plunging  the  dry  stuff 
into  solutions  of  the  salts,  and  determining  the  density  of  the  solution  before  the  immersion 
and  after  withdrawing  the  stuff.  Wool  abstracts  alum  from  its  solution,  but  it  gives  it  all 
out  again  to  boiling  water.  The  sulphates  of  iron,  copper,  and  zinc  resemble  alum  in  this 
respect.  Silk  steeped  for  some  time  in  a  solution  of  protosulphate  of  iron,  abstracts  the 
oxide,  and  gets  thereby  dyed,  and  leaves  the  solution  acidulous.  Cotton  in  nitrate  of  iron 
produces  the  same  effect.  Wool  put  in  contact  with  cream  of  tartar,  decomposes  a  portion 
of  it ;  it  absorbs  the  acid  within  its  pores,  and  leaves  a  neutral  salt  in  solution  in  the  liquor. 


DYEING.  475 

Cotton  produces  no  such  effect  with  tartar,  showing  by  these  different  effects  that  there  are 
certain  attractions  between  the  stuff  and  dyes.  This  attraction,  however,  may  be  more 
what  is  termed  a  catalytic  intiuence,  the  fibres  of  the  stuff  producing  a  chemical  action  with 
the  salt  or  dye  with  which  it  is  in  contact.  This  attraction  or  affinity  of  the  fibre  for  the 
dye- drug  does  not  produce  a  very  extensive  effect  in  the  processes  of  dyeing.  More  prob- 
ably the  power  of  imbibing  and  retaining  colors  possessed  by  the  fibre  is  more  dependent 
upon  a  mechanical  than  a  chemical  influence. 

All  dye-drugs  must  in  the  first  instance  be  brought  into  a  state  of  solution,  in  order  that 
the  dye  may  be  imbibed  by  the  fibre  ;  but  if  the  fibre  exerts  no  attraction  for  the  color  so 
as  to  retain  it,  it  is  evident  that  so  long  as  it  remains  capable  of  dissolving  in  water,  the 
stuffs  being  brought  into  contact  with  water  will  soon  lose  their  color.  A  color  thus  formed 
does  not  constitute  a  dye,  however  strongly  stained  the  stuH's  may  appear  to  be,  in  or  out 
the  dyeing  solution  ;  in  order  to  form  a  dye,  the  color  must  be  fixed  upon  or  within  the 
stuff  in  a  condition  insoluble  in  water.  Hence  the  mere  immersion  of  the  stuff  into  a  solu- 
tion of  a  color  will  not  constitute  a  dye,  except  where  the  stuff  really  has  an  attraction  for 
the  color  and  retains  it,  or  causes  a  decomposition  by  which  an  insoluble  compound  is  fixed 
upon  it,  such  as  referred  to  by  putting  stuffs  into  solutions  of  iron.  The  abstraction  of  the 
color  from  a  solution  by  the  immersion  of  the  stuff,  is  often  the  result  of  a  mechanical  at- 
traction possessed  by  porous  substances,  enabling  them  to  absorb  or  imbibe  certain  color- 
ing matters  from  solutions  that  are  held  by  a  weak  attraction  by  their  solvents.  On  this 
principle,  a  decoction  of  cochineal,  logwood,  brazil-wood,  or  a  solution  of  sulphate  of  in- 
digo, by  digestion  with  powdered  bone  black,  lose  their  color,  in  consequence  of  the  color- 
ing particles  combining  by  a  kind  of  capillary  attraction  with  the  porous  carbon,  without 
undergoing  any  change.  Tlio  same  thing  happens  when  well  scoured  wool  is  steeped  in 
such  colored  liquids ;  and  the  color  which  the  wool  assumes  by  its  attraction  for  the  dye  is, 
with  regard  to  most  of  the  above  colored  solutions,  but  feeble  and  fugitive,  since  the  dye 
may  be  again  abstracted  by  copious  washing  with  simple  water,  whose  attractive  force, 
therefore,  overcomes  that  of  the  wool.  The  aid  of  a  high  temperature,  indeed,  is  requisite 
for  the  abstraction  of  the  color  from  the  wool  and  the  bone-black,  probably  by  enlarging 
the  size  of  the  pores,  and  increasing  the  solvent  power  of  the  water. 

Those  dyes,  whoso  coloring  matter  is  of  the  nature  of  extractive,  form  a  faster  combi- 
nation with  stuffs.  Thus  the  yellow,  fawn,  and  brown  dyes,  which  contain  tannin  and  ex- 
tractive, become  oxygenated  by  contact  of  air,  and  insoluble  in  water ;  by  which  means 
they  can  impart  a  durable  dye.  When  wool  is  impregnated  with  decoctions  of  that  kind, 
its  pores  get  charged  by  capillarity,  and  when  the  liquid  becomes  oxygenated,  they  remain 
filled  with  a  color  now  become  insoluble  in  water.  The  fixation  of  iron  oxide  and  several 
other  bases  also  depends  on  the  same  change  within  the  pores  or  fibre  ;  hence  all  salts  that 
have  a  tendency  to  pass  readily  into  the  basic  state  are  peculiarly  adapted  to  act  as  a  me- 
'dium  for  fixing  dyes ;  however,  this  property  is  not  essential. 

In  order  to  impart  to  the  stuffs  tlic  power  of  fixing  the  color  in  an  insoluble  form  upon 
it,  recourse  is  had  to  other  substances,  which  will  combine  with  the  soluble  and  form  with 
it  an  insoluble  color ;  and  it  is  not  necessary  that  this  new  substance  should  have  an  attrac- 
tion for  the  stuff,  or  be  cajiable  of  passing  into  a  basic  form,  any  more  than  the  original 
color,  but  it  is  necessary  that  it  be  rendered  insoluble  while  in  contact  with  the  stuff. 

Such  substances  used  to  unite  the  color  with  the  stuff  have  been  termed  mordants,  which 
meant  that  they  had  a  mutual  attraction  for  the  stuff  and  color,  and  combining  with  the 
st.uff  first,  they  afterwards  took  up  the  color  ;  but  this  is  only  so  in  some  instances.  A  few 
examples  will  illustrate  the  bearing  of  these  mordants.  If  a  piece  of  cotton  stuff  is  put 
into  a  decoction  of  logwood,  it  will  get  stained  of  a  depth  according  to  the  color  of  the 
solution,  but  this  stain  or  color  may  be  washed  from  the  cotton  by  putting  it  into  pure 
water,  the  color  being  soluble.  If  another  piece  of  cotton  stuff  be  put  into  a  solution  of 
protosulphate  of  iron,  and  then  washed  from  this,  a  portion  of  the  iron  will  have  undergone 
oxidation,  and  left  the  acid,  and  become  fixed  upon  the  fibre  and  insoluble  in  water. 
Whether  this  oxidation  is  the  result  of  an  influence  of  the  stuff,  or  the  effect  of  the  oxygen 
of  the  air  and  water  in  which  the  goods  are  exposed,  it  does  not  matter  meantime,  only 
this  fixed  oxide  constitutes  an  example  of  a  mordant  by  its  combining  with  the  stuif.  If 
this  stuff  is  now  put  into  a  decoction  of  logwood,  the  cohn-ing  matter  of  the  logwood  will 
combine  with  the  oxide  of  iron  fixed  upon  the  fibre^  and  form  an  insoluble  color,  which 
after  washing  will  not  remove  from  the  stuff.  If,  instead  of  washing  the  stuff  from  the  sul- 
])hate  of  iron  solution  in  water,  it  be  passed  through  an  alkaline  lye  of  soda  or  potash,  the 
acid  holding  the  iron  in  solution  is  taken  hold  of  by  the  alkali,  and  removed.  Tiie  oxide  of 
iron  is  thus  left  upon  the  stuff,  in  a  much  larger  quantity  than  in  the  former  case,  and  as 
firmly  fixed,  although  not  by  any  attraction  between  it  and  tlie  fibre,  l)ut  simi)ly  being  left 
within  it.  And  this  stuff  being  now  ])ut  into  the  logwood  liquor,  will  form  a  dye  of  a 
depth  according  to  tlie  ([uantity  of  iron  thus  fixed  upon  the  stuff,  and  equally  permanent 
with  that  which  had  been  fixed  on  the  stuff  by  the  oxidation  in  working. 


470  DYEING. 

Such,  then,  are  the  methods  of  fixing  within  the  stuff  insoluble  colors  from  soluble 
eoinpounJs,  and  from  these  remarks  the  necessity  of  liaving  the  dye  in  solution  will  also  be 
evident. 

Suppose,  again,  that  the  sulphate  of  iron  be  mixed  with  the  logwood  decoction,  there 
will  be  produced  the  same  color  or  dye  as  an  insoluble  precipitate  :  if  the  cotton  stuff  is  put 
into  this,  no  color  worthy  of  the  name  of  a  dye  will  be  obtained,  as  the  cotton  will  not 
imbibe  within  its  fibre  this  precipitate.  Place  woollen  stuff  in  the  same  liquid,  there  is 
formed  a  very  good  dye,  the  woollen  fil)re  having  mibibed  a  great  portion  of  the  solid  pre- 
cipitate, probably  owing  to  woollen  fibres  being  much  larger  than  those  of  cotton.  Thus, 
with  cotton  and  other  stuff  that  will  not  imbibe  freely  solid  precipitates,  the  mordant  must 
be  fixed  within  the  fibre  previous  to  applying  the  coloring  substances,  such  as  the  vegetable 
decoctions.  It  will  also  be  seen  that  the  dye  which  is  the  product  of  combination  between 
the  mordant  and  color  is  not  that  of  the  natural  color  of  the  drug,  but  the  color  of  the  com- 
pound. Hence  the  great  variety  of  tints  capable  of  being  produced  from  one  dye-drug,  by 
varying  either  the  kind  or  intensity  of  the  mordant.  So  that  in  the  aliove  instances,  it  is 
not  the  color  of  the  hematoxylin  fixed  on  the  stuff,  but  its  compound  wilh  iron,  or  tin,  or 
alumina,  as  the  case  may  lie,  all  of  which  give  difi'ercnt  tints. 

It  is  upon  this  principle  of  rendering  bases  insoluble  while  within  the  fibre  by  chemical 
means,  that  has  brought  to  the  use  of  the  dyer  a  great  number  of  mineral  dyes  which  in 
themselves,  whether  separate  or  combined,  have  no  attraction  whatever  for  the  fibre  ;  such 
as  solutions  of  sulphate  of  copper,  and  yellow  prussiate  of  potash,  nitrate  of  lead,  and 
bichromate  of  potash,  kc.  Suppose  the  stuff  to  be  dyed  a  yellow  by  the  two  last-named 
salts,  was  first  put  into  the  solution  of  lead  and  then  washed  previous  to  being  put  into  the 
bichromate  solution,  the  greater  portion  of  the  lead  would  be  dissolved  from  the  stuff,  and 
a  very  weak  color  would  be  obtained.  If  the  stuff  I'rom  the  lead  solution  was  put  directly 
into  the  bichromate  solution,  a  very  good  dye  would  be  the  result ;  but  the  portion  of  the 
solution  remaining  upon  the  surface  of  the  stuff  will  combine  with  the  chrome  and  form  a 
precipitate  which  the  fibre  cannot  imbibe,  but  will  form  an  external  crust  or  pigment  upon 
the  surface,  which  blocks  up  the  pores,  and  exhausts  to  no  purpose  the  dye,  causing  great 
waste  :  hence  the  stulF  from  the  solution  of  lead  is  put  into  water  containing  a  little  soda 
or  lime,  and  the  lead  is  thus  reduced  to  an  insolulile  oxide  within  the  fibre.  The  goods 
may  now  be  washed  from  any  loose  oxide  adhering,  and  then  passed  through  the  bichro- 
mate solution,  when  the  chromic  acid  combines  with  the  oxide  of  lead,  forming  a  perma- 
nent yellow  dye.  Thus  it  will  be  seen  that  whether  the  combination  of  the  color  with  the 
stuff  be  chemical  or  mechanical,  the  production  of  the  dye  which  is  fixed  upon  the  fibre  is 
certainly  a  chemical  question,  and  the  dyer  should  be  familiar  with  the  nature  and  principles 
of  these  reactions. 

There  are  a  few  instances  where  the  dye  produced  does  not  come  within  the  sphere  of 
these  principles,  there  being  no  mordants  required,  nor  any  combination  of  the  color  fbrnicd 
within  the  stuff,  but  the  dye-drug  in  its  natural  hue  is  fixed  within  the  fibre.  Such  colors 
have  been  termed  mbsfantivc,  to  distinguish  them  from  those  produced  by  means  of  mor- 
dants, which  are  termed  adjective.  Amongst  this  class  of  dyes  and  dye-drugs  stands  pre- 
eminent indigo-blue.  Indigo  in  its  natural  state  is  entirely  insoluble  in  water,  and  is  of  a 
deep  blue  color.     The  composition  of  this  blue  indigo  is  represented  as — 

Carbon       -         -         -         -         ^''      I      Nitrogen      -         .         .         .         l 
Hydrogen  -         -         -         -  5       |       Oxygen        -         ...         2 

But  it  is  found  capable  of  parting  with  a  portion  of  the  oxygen,  and  by  so  doing,  losing 
entirely  its  blue  color ;  and  in  this  deoxidized  condition  it  is  soluble  in  alkaline  lyes  and 
lime  water ;  this  colorless  compound  is  termed  indigogene.  The  opinion  of  Liebig  upon 
the  constitution  of  this  substance  is,  that  indigo  contains  a  salt  radical,  which  he  terms 
Anjilc.^  composed  of  C"^H^N.  He  considers  that  indigogene  or  white  indigo  is  the  hydratcd 
protoxide  of  this  radical,  and  that  blue  indigo  is  the  peroxide,  represented  thus  : — 

C        IT       N       O  Water. 

Salt  radical,  anylc 1C>       5       1       0       0 

Indigogene 16       5       111 

Blue  indigo IG       5       1        2       0 

Advantage  is  taken  of  this  property  of  indigo,  of  ]iartlng  with  its  oxygen  and  becoming 
soluble,  to  ai)ply  it  to  dyeing,  and  it  is  effected  by  the  following  means,  when  lor  the  pur- 
pose of  dyeing  vegetable  stuff,  as  cotton  ;  and  from  the  circumstance  of  these  operations 
i)eiiig  done  cold,  the  method  is  termed  the  cold  vat,  whieh  is  made  upas  follows: — The 
indigo  is  reduced  to  an  impalpable  pulp,  by  being  ground  in  water  to  the  consistence  of 
thick  cream.  This  is  ptit  into  a  suitable  vessel  filled  with  water,  along  with  a  quantity  of 
copperas  and  newly  slaked  lime,  and  the  whole  well  mixed  by  stirring.  After  a  .'ihort  time 
the  indigo  is  deoxidized  and  rendered  soluble  by  a  portion  of  the  lime  which  is  added  in 
excess,  the  reaction  being  represented  thus  : — 


DYEING.  477 

Indigo,  composed  of  I  J^'^^^^I^S"'^"  ;     ;     ;    ;- ^  Dyeing  Solution. 


r  Protoxide  of  Iron     . ^^.C^  Peroxide  of  Iron. 

-    „  Protoxide  ot  Iron 

2.  Copperas      -        -     ^  guiphuHcAcid       . 

[_  Sulphuric  Acid 


TLime —  /  ^"-^  ^^^"^^     Sulphate  of  Lime. 

Lime    -        -         -     ]  Lime -/_I__^^   Sulphate  of  Lime. 


I^Lime 

The  peroxide  of  iron  and  sulphate  of  lime  are  precipitated  to  the  bottom,  and  the  indigo- 
gene  and  lime  form  a  solution  of  a  straw  color,  with  darli  veins  through  it. 

The  operation  of  dyeing  by  this  solution  is  simply  immersion,  technically,  dipping.  The 
stuff  by  immersion  imbibes  the  solution,  and  wiien  taken  out  and  exposed  to  the  air,  the 
indigogene  i/pon  and  within  the  fibre  rapidly  talces  oxygen  fi-om  the  atmosphere,  and  be- 
comes indigo  blue,  thus  forming  a  permanent  dye,  without  any  necessary  attraction  Ijetween 
the  indigo  and  the  stuff. 

The  indigo  vat  for  wool  and  silk  is  made  up  with  indigo  pulp,  potash,  madder,  and  bran. 
In  this  vat  the  extracts  of  madder  and  bran  perform  the  deoxidizing  functions  of  the  cop- 
peras in  the  cold  vat,  by  undergoing  a  species  of  fermentation. 

Pastel  and  wood,  either  alone  or  with  the  addition  of  a  little  indigo,  are  also  used  for  the 
dyeing  of  wool  and  silk  stuff,  the  deoxidation  being  cfTected  by  the  addition  of  bran,  mad- 
der, and  weld.  In  dyeing  with  these  vats,  the  liquor  is  made  warm,  and  they  require  much 
skill  and  experience  to  manage,  in  consequence  of  their  complexity,  being  always  liable  to 
go  out  of  condition,  as  the  dyeing  goes  on,  by  the  extraction  of  the  indigogene  and  the  mod- 
ification of  the  fermentable  matter  employed  to  deoxidize  the  indigo  to  supply  that  loss. 
The  alkaline  solvent  also  undergoes  change,  so  there  must  be  successive  additions  of  indigo 
and  alkali ;  the  principal  attention  of  the  dyer  is  the  maintaining  the  proper  relation  of  these 
matters,  as  too  much  or  too  little  of  either  is  injurious. 

Sulphate  of  indigo  forms  an  intense  blue  solution,  unaffected  also  by  mordants.  Vege- 
table stuffs  dipped  in  this  retain  no  dye,  for  the  washing  off  the  acid  in  order  to  preserve 
the  fibre  removes  the  color ;  but  animal  fibre,  such  as  woollen  and  silk,  becomes  dyed ;  a 
portion  of  the  blue  remains  upon  the  stuff  after  washing  off  the  acid,  being  retained  l)y 
capillary  attraction.  This  dye  is  termed  Saxon  blue,  but  it  has  very  little  of  the  permanence 
of  indigo  or  vat  blue,  although  it  is  also  a  substantive  color. 

Another  truly  substantive  color  is  that  dyed  by  carthamus  or  safflower,  but  the  fixation 
of  this  dye  upon  the  stuff  differs  from  any  of  those  referred  to.  Like  indigo,  it  has  no 
affinity  for  any  base  or  substance  capaljle  of  forming  a  mordant ;  its  solvent  is  an  alkali, 
but  in  this  dissolved  state  it  does  not  form  a  dye.  The  mode  of  proceeding  in  dyeing  with 
carthamus  is  first  to  extract  the  dye  from  the  vegetable  in  which  it  is  found,  by  soda  or 
potash,  which  is  afterwards  neutralized  by  an  acid  previous  to  dyeing,  which  renders  the 
color  insoluble,  but  in  so  fine  a  state  of  division  that  no  precipitation  can  be  seen  for  some 
time,  and  the  stuff  immersed  in  this  imbibes  the  color  within  its  fibre,  its  lightness  assisting 
this  action,  as  the  precipitate  will  remain  suspended  in  water  for  days  before  it  will  subside. 
Vegetable  fibre  takes  up  this  dye  as  easily  as  animal,  but  whether  by  an  attraction  for  the  stuff, 
or  by  a  mechanical  capillary  attraction  of  the  fibre,  is  not  so  easily  determined.  A  piece  of 
stuff  suspended  in  a  vessel  filled  with  water,  having  in  it  some  insoluble  carthamine,  all  the 
coloring  particles  will  flow  to  and  combine  with  the  fibre  from  a  considerable  distance,  giv- 
ing a  proof  of  the  existence  of  some  force  drawing  them  together. 

Such  then  are  the  various  conditions  and  principles  involved  in  the  processes  of  fixing 
the  dye  within  or  upon  the  stuff. 

During  the  operations  of  dyeing  there  are  certain  circumstances  which  have  to  be  attended 
to,  in  order  to  facilitate  and  effect  certain  hues  or  tints  of  color.  Thus,  with  many  of  tlie 
coloring  substances,  heat  not  only  favors  but  is  necessary  for  the  solution  of  the  dye,  and 
also  its  combination  with  the  stuff  or  mordant.  Decoctions  of  woods  are  always  made  by 
liot  water,  and  the  dyeing  processes  with  decoctions  are  in  hot  lirpior.  When  tlie  coloring 
matter  of  quercitron-bark  is  extracted  by  boiling  water,  the  color  pioduced  upon  tiie  stuff  will 
be  a  rieli  amber  yellow,  but  if  the  extract  be  made  by  water  at  180°  Fahr.,  a  beautiful  lemon 
yellow  will  be  the  dye  produced  by  it,  using  tlie  same  mordant  in  each  case.  Colors  dyed 
Ity  madder  and  Barwood  must  be  done  at  a  boiling  lieat  during  the  whole  process,  or  no 
dye  is  effected.  Sumacli,  another  astringent  substance',  is  most  advantageously  applied  at 
a  boiling  lieat;  and  in  order  to  have  a  large  l)ody  of  tliis  dye  fixed  upon  the  stuff,  it  should 
be  immersed  in  the  liquor  while  hot  and  allowed  to  cool  together,  duiing  which  the  tamiin 
of  tlie  dye  undergoes  some  reniarkal)le  change  in  contact  witli  the  stuff.  Safllower  dyes  are 
kept  cold,  so  are  tin  l>ases,  Prussian  blues,  and  chrome  yellows:  liy  applying  heat  to  tlie 
last  a  similar  result  is  effected  to  that  with  bark  ;  instead  of  a  lemon  yellow  an  amber  yel- 


478  DYEING. 

low  will  be  obtained.  Almost  all  colors  are  affected  less  or  more  by  the  temperature  at 
which  they  are  produced.  Some  mordants  are  fixed  upon  the  stulf  by  heat,  such  as  acetate 
of  alumina ;  the  stuff  l>eing  dried  from  a  solution  of  this  salt  at  a  high  temperature  loses 
part  of  the  acid  by  b"ing  volatilized,  and  there  remal;.s  upon  the  fibre  an  insoluble  suboxide, 
which  fixes  the  dye.  These  remarks  respecting  the  methods  apply  more  particularly  to 
vegetable  stuffs,  as  cotton,  and  in  many  cases  also  to  silk,  but  wool  is  always  dyed  at  a  high 
heat.  Although  wool  seems  to  have  a  much  greater  absorbing  power  than  cotton,  the  lat- 
ter will  absorb  and  become  strongly  dyed  in  a  cold  dye  bath,  in  which  wool  would  not  be 
alfected ;  but  apply  heat  and  the  wool  will  be  deeply  dyed,  and  the  dye  much  more  perma- 
nent than  the  cotton. 

The  [lermanence  of  colors  is  another  property  to  be  carefully  studied  by  the  practical 
dyer,  as  the  color  must  not  be  brought  under  circumstances  that  will  destroy  its  permanency 
during  any  of  the  operations  of  the  dye-house.  The  word  permanent,  however,  does  not 
mean  /«s/,  which  is  a  technical  term  applied  to  a  color  that  will  resist  all  ordinary  opera- 
tions of  destruction.  As,  for  instance,  a  Prussian  blue  is  a  permanent  color,  but  not  a  fast 
color,  as  any  alkaline  matter  will  destroy  it ;  or  a  common  black  is  permanent,  although  any 
acid  matters  will  destroy  it ;  while  Turkey  red  is  a  fast  color,  and  not  affected  by  either  acid 
or  alkaline  matters.  A  few  of  the  circumstances  affecting  colors  in  the  i)roccsses  they  are 
subjected  to  may  be  referred  to  in  this  place.  If,  for  instance,  the  air  in  drying  the  dyed 
etufi"  in  a  hot  chamber  be  moist,  there  is  a  great  tendency  to  the  color  being  impaired  in 
these  circumstances.  For  example,  a  red  color  dyed  with  safilower  will  pass  into  brown,  a 
Prussian  blue  will  pass  into  a  gray  lavender,  chrome  yellows  take  an  amber  tint.  Mostly  all 
colors  are  affected  less  or  more  by  being  subjected  to  .strong  heat  and  moisture  ;  even  some 
of  those  colors  termed  fast  are  affected  under  such  circumstances.  A  dry  heat  has  little  or 
no  efl'ect  upon  any  color,  and  a  few  colors  are  made  brighter  in  their  tint  by  such  a  heat,  as 
chrome  orange,  indigo  blue,  on  cotton,  &c. 

Some  of  these  effects  of  heat  and  moisture  differ  with  different  stuff;  thus  indigo  blue 
upon  cotton  is  not  so  much  affected  as  indigo  blue  upon  silk,  while  safflower  red  upon  cot- 
ton will  be  completely  destroyed  before  the  game  color  upon  silk  will  be  perceptibly  affected. 
The  same  coloring  matter  fixed  by  different  mordants  upon  the  same  stuff  is  also  differently 
affected  under  these  conditions. 

Light  is  another  agent  effecting  a  great  influence  upon  the  permanence  of  colors,  which 
should  be  also  considered  by  the  dyer.  Reds  dyed  by  a  Erazil  wood  and  a  tin  mordant, 
exposed  to  the  light,  become  brown ;  Prussian  blue  takes  a  purple  tint ;  yellow  becomes 
brownish ;  safflower  red,  yellowish,  and  these  changes  are  facilitated  by  the  presence  of 
moisture  ;  such  as  exposing  them  to  stiong  light  while  drying  from  the  dye-bath,  cither  out 
or  within  doors.  The  direct  i-ays  of  the  sun  destroy  all  dyed  colors ;  even  Turkey  red  yiekls 
before  that  agency. 

BoUinrj  was  formerly  prescribed  in  France  as  a  test  of  fast  dyes.  It  consisted  in  putting 
a  sample  of  the  dyed  goods  in  boiling  water,  holding  in  solution  a  determinate  quantity  of 
alum,  tartar,  soap,  vinegar,  .&c.  Dufay  improved  that  barbarous  test.  He  considered 
that  fast-dyed  cloth  could  be  recognized  by  resisting  an  exposure  of  twelve  hours  to  the 
sunshine  of  summer,  and  to  the  midnight  dews ;  or  of  sixteen  days  in  winter. 

In  trying  the  stability  of  dyes,  we  may  offer-  the  following  rules  : — 

That  every  stuff  .should  be  exposed  to  the  light  and  air ;  if  it  be  intended  to  be  worn 
abroad,  it  should  be  exposed  also  to  the  wind  and  rain  ;  that  carjH  ts,  moreover,  should  be 
subjected  to  friction  and  pulling,  to  prove  their  tenacity ;  and  that  cloths  to  be  washed 
should  be  exposed  to  the  action  of  hot  water  and  soap.  However,  such  tests  are  not  at  all 
applicable  to  most  of  the  colors  dyed  upon  cotton  stuff.  Not  many  of  them  can  stand  the 
action  of  hot  water  and  soap,  oi'  even  such  acids  as  the  juice  of  fruits.  Indigo  blue,  one  of 
the  most  permanent  dyes  on  cotton,  yields  its  intensity  to  every  operation  of  wasliing,  even 
in  pure  water. 

1.  Red  with  blue  produces  purple,  violet,  lilac,  pigeon's  neck,  mallow,  peach-blossom, 
hJeii  de  roi,  lint-blossom,  amaranth. 

Thus  a  Prussian  blue  dyed  over  a  safflower  red,  or  vice  versa,  will  produce  any  of  these 
tints  by  varying  the  depth  of  the  red  and  blue  according  to  the  shade  required ;  but  the 
same  shades  can  be  produced  direct  by  logwood  and  an  aluminous  or  tin  mordant ;  the  stuff' 
l)eing  steeped  in  sumach  liquor  previous  to  applying  the  tin  mordant  produces  the  reddish 
or  purple  tint  when  such  is  required. 

2.  Red  with  black  ;  brown,  chocolate,  maroon,  Szc.  These  tints  are  produced  by  vari- 
ous processes.  To  dye  a  deep  orange  by  annotto  liquor,  and  then  form  over  it  a  black  by 
sumach  and  sulphate  of  iron,  gives  a  l)rown  ;  or  dye  the  stuff  first  a  rich  yellow  by  quer- 
citron and  a  tin  mordant,  and  tlien  over  the  yellow  produce  a  purple  by  passing  it  through 
logwood  ;  chocolates  are  thus  ))roduced.  A  little  Brazil  wood  with  the  logwood  gives  more 
of  the  red  element.  When  maroon  is  required,  the  rod  is  made  to  prevail,  and  so  by  a 
judicious  mixture  these  various  tints  are  produced.  Brown,  especially  upon  cotton  fibre,  is 
more  often  produced  direct  by  means  of  catechu.     Steep  the  stuff  in  a  hot  solution  of  cate 


EDGE  TOOLS.  479 

chu,  in  which  the  gummy  principle  has  been  destroyed  by  the  addition  of  a  salt  of  copper ; 
then  pass  through  a  solution  of  bichromate  of  potash  at  boiling  heat,  when  a  rich  brown  is 
obtained. 

3.  Yellow  with  blue ;  green  of  a  great  variety  of  shades,  such  as  nascent  green,  gay 
green,  grass  green,  spring  green,  laurel  green,  sea  green,  celadon  green,  parrot  green,  cab- 
bage green,  apple  green,  duck  green. 

Green  is  essentially  a  mixed  dye,  and  produced  by  dyeing  a  blue  over  a  yellow  or  a  yel- 
low over  a  blue.  In  almost  all  cases  the  blue  is  dyed  first,  and  then  the  yellow,  and  accord- 
ing to  the  depth  of  each  or  any  of  these  are  the  various  tints  of  green  produced.  ^Vith 
silk  and  wool,  one  kind  of  green  dye  may  be  produced  simultaneously  by  putting  sulphate 
of  indigo  into  the  yellow  dye-bath,  and  then  working  the  previously  prepared  or  mordanted 
stuff  in  this.  With  cotton,  an  arseuite  of  copper  (Scheele's  green)  may  be  produced  by 
working  the  stuff  in  a  solution  of  arsenite  of  potash  or  soda,  and  then  in  sulphate  of  cop- 
per, which  produces  a  peculiar  tint  of  green. 

4.  Mixtures  of  colors,  three  and  three,  and  four  and  four,  produce  an  indefinite  diversity 
of  tints :  thus,  red,  yellow,  and  blue  form  brown  olives  and  greenish  grays ;  in  which  the 
blue  dye  ought  always  to  Ijc  first  given,  lest  the  indigo  vat  should  be  soiled  by  other  colors, 
or  the  "other  colors  spoiled  by  the  alkaline  action  of  the  vat.  Red,  yellow,  and  gray,  (which 
is  a  graduation  of  black,)  give  the  dead-leaf  tint,  as  well  as  dark  orange,  snuff  color,  &c. 
Red,  blue,  and  gray  give  a  vast  variety  of  shades ;  as  lead  gray,  slate  gray,  wood-pigeon 
gray,  and  other  colors  too  numerous  to  specify.     See  Brown  Dye. 

Care  must  be  taken,  however,  in  mixing  these  colors,  to  study  the  depth  of  the  tint  re- 
quired ;  as,  for  instance,  were  we  wishing  to  dye  a  slate  gray,  and  to  proceed  first  by  dye- 
ing a  blue,  then  a  red,  with  a  little  of  the  gray,  we  would  produce,  instead  of  a  slate  gray, 
a  purple  or  peach.  The  arrangement  referred  to,  applies  only  to  the  elements  of  the  colors 
that  enter  into  the  composition  of  the  various  tints,  so  that  a  slate  gray  is  a  blue  with  a 
small  portion  of  red,  and  a  still  smaller  portion  of  the  black  element,  that  produces  the 
gray  tint.  Tlius,  dye  the  stuff  first  a  deep  sky-blue  by  the  vat,  then  by  passing  through  a 
solution  of  sumach,  with  a  small  quantity  of  logwood,  Brazil  wood,  copperas,  and  alum, 
gray  will  be  produced.  The  Brazil  wood  gives  the  red  tint,  sumach  and  copperas  the  black 
tint,  the  logwood  assisting  in  this,  and  with  the  aid  of  the  alum  throwing  in  the  puce  or 
dove-neck  hue  ;  and  thus,  by  the  variation  of  these  hues  by  such  arrangements,  any  of  the 
gray  tints  can  be  produced.     See  Calico  Printing. 

EBONY.     Of  this  black  wood  three  kinds  are  imported : — 

The  Mauritius  Ehony^  which  is  the  blackest  and  finest  grain. 

The  Ea&t  Indian  Ebony^  which  is  not  of  so  good  a  color. 

The  African  Ebony,  which  is  porous,  and  bad  in  point  of  color. 

The  ebony  of  the  Mauritius  is  yielded  by  the  Diospyriis  Ebenus.  Colonel  Lloyd  says 
this  ebony,  when  first  cut,  is  beautifully  sound,  but  that  it  splits  like  all  other  woods  from 
neglectful  exposure  to  the  sun.  The  workmen  who  use  it  immerse  it  in  water  as  soon  as  it 
is  felled  for  from  six  to  eighteen  months  ;  it  is  then  taken  out,  and  the  two  ends  are  secured 
from  splitting  by  iron  rings  and  wedges.  Colonel  Lloyd  considers  that  next  to  the  Mau- 
ritius, the  ebony  of  Madagascar  is  the  best,  and  nest  that  of  Ceylon. 

The  Mauritius  ebony  is  imported  in  round  sticks  like  scaffold  poles,  about  fourteen  inches 
in  diameter.  The  East  Indian  variety  comes  to  us  in  logs  as  large  as  tweirty-eight  inches 
diameter,  and  also  in  planks.  The  Cape  of  Good  Hope  ebony  arrives  in  England  in  billets, 
and  is  called  billet  wood,  about  from  three  to  six  feet  long,  and  two  to  four  inches  thick. 

The  uses  of  ebony  are  well  known. 

White  Ebony  comes  from  the  Isle  of  France,  and  is  much  like  box-wood. 

EDGE  TOOLS;  more  properly  cx^Vh//  tools,  of  which  the  chisel  maybe  regarded  as 
tlie  type.  Holtzapffel,  whose  book  on  Mechanical  Manipulation  is  the  best  to  be  found  in 
any  language,  divides  cutting  tools  into  three  groups, — namely,  paring  tools,  scraping  tools, 
and  shearing  tools. 

First.  Paring  or  splitting  tools,  with  thin  edges,  the  angles  of  which  do  not  exceed  sixty 
degrees  ;  one  plane  of  the  edge  being  nearly  coincident  with  the  plane  of  the  work  produced, 
(or  with  the  tangent  in  circular  work.)  These  tools  remove  the  fibres  principally  in  the 
direction  of  their  length,  or  longitudinally,  and  they  produce  large  coarse  chips  or  shav- 
ings, by  acting  like  the  common  wedge  applied  to  mechanical  power. 

Secondly.  Scraping  tools,  with  thick  edges,  that  measure  from  sixty  to  one  hundred  and 
twenty  degrees.  The  planes  of  the  edges  form  nearly  equal  angles  with  the  surface  pro- 
duced, or  else  the  one  plane  is  nearly  or  quite  perpendicular  to  the  face  of  the  work,  (or 
becomes  as  a  radius  to  the  circle.)  These  tools  remove  the  fibres  in  all  directions  with 
nearly  equal  facility,  and  they  produce  fine  dust-like  shavings  by  acting  superficially. 


4b  U 


ELASTIC  BAiJDS. 


Tliirdly.  Shearing,  or  separating  tools,  with  edges  of  from  sixty  to  ninety  degrees;  gen- 
erally duplex,  and  then  applied  on  opposite  sides  of  the  substances.  One  plane  of  each 
tool,  or  of  the  single  tool,  coincident  with  the  plane  produced. 

ELASTIC  BANDS.  {2'tssus  ilastiques,  Fr.  ;  Federltavz-zeige,  Gefm.)  See  Caoutchocc 
and  Braiding  Machine. 

ELASTICITY.  The  property  which  bodies  possess  of  occupying,  and  tending  to  occupy, 
portions  of  space  of  determinate  volume,  or  determinate  volume  and  figure,  at  given  pres- 
sures and  temperatures,  and  wliich,  in  a  homogeneous  body,  manifests  itself  equally  in  every 
part  of  appreciable  magnitude,  {Nuhol.)  The  examination  of  this  important  subject  in 
Kinetics  does  not  belong  to  this  work.  A  few  remarks,  and  some  explanations,  only  are 
necessary. 

Elastic  Pressure  is  the  force  exerted  between  two  bodies  at  their  surface  of  contact. 

Compression  is  measured  by  the  diminution  of  volume  which  the  compressible  (elastic) 
body  undergoes. 

The  Modulus  or  Coefficieiit  of  Elasticity  of  a  liquid  is  the  ratio  of  a  pressure  applied 
to,  and  exerted  by,  the  liquid  to  the  accompanying  compression,  and  is  therefore  the  recip- 
rocal of  the  compressibility.  The  quantity  to  which  the  term  Modulus  of  Elasticity  was 
first  applied  by  Dr.  Young,  is  the  reciprocal  of  the  extensibility  or  longitudinal  pliability. 
(See  the  Edinburgh  Transactions,  and  those  of  the  Royal  Society,  for  the  papers  of  Barlov, 
Jfnxircll,  and  Jia7iki7ie,  and  the  British  Association  Reports  for  those  of  Fairbairn,  Hodg- 
kinson,  &c.) 

Various  tables,  showing  the  elasticity  of  metals,  glass,  &c.,  have  been  constructed,  and 
will  be  found  in  treatises  on  mechanics.  The  following  notices  of  the  mechanical  proper- 
ties of  woods  may  prove  of  considerable  interest.  The  experiments  were  by  Chevandier 
and  Wertheim. 

Rods  of  square  section  10  mm  in  thickness  and  2  ra  in  length  were  prepared,  being  cut 
in  the  direction  of  the  fibres,  and  the  velocity  of  sound  in  them  was  determined  by  the 
longitudinal  viljrations,  their  elasticity  from  their  increase  in  length,  and  tlicir  cohesion  by 
loading  them  to  the  point  of  rupture.  Small  rods  were  cut  in  planes  perpendicular  to  the 
fibre  grain,  (in  directions  radial  and  tangential  to  the  rings  of  growth,)  and  their  elasticity 
and  sound  velocity  were  measured  by  the  lateral  vibrations.  It  was  thus  again  established, 
that  the  coefficients  of  elasticity,  as  deduced  from  the  vibrations,  come  out  higher  than  those 
derived  from  the  elongation. 


Nnmea  of  the  wooJb. 


Density. 

Sjund  velocity. 

Coefficients  of  elasticity. 

CohebioD. 

L. 

E. 

T. 

L. 

Pv. 

T. 

L. 

E. 

0-7]  T 

14-9 





1216-9 





7-93 



0-493 

13-96 

8-05 

4-72 

1113-2 

94-5 

34-1 

4-18 

0-220 

0-756 

11 -SO 

10-28 

7-20 

1085-7 

208-4 

103-4 

2-99 

1  -007 

0-&12 

13-32 

6-46 

9-14 

997-2 

81-1 

155-2 

4-30 

0823 

0-S2.3 

10-06 

11-00 

8-53 

9804 

269-7 

159-3 

8-57 

0-885 

0-S08 

— 

— 

— 

977-8 

— 

— 

6-49 

— 

0-ST2 

11-58 

9-24 

7-76 

921-3 

lSS-7 

129-S 

5-66 

0-5S2 

0-&59 

lu-on 

S-53 

4-78 

564-1 

97-7 

28-6 

2-48 

0-256 

0-69-2 

13-4.3 

9-02 

685 

1I63-S 

134-9 

80-5 

616 

0-522 

0-697 

14-05 

8-39 

7-60 

1121-4 

111-3 

102  0 

678 

0-21S 

0-601 

13-9.5 

8-25 

6-28 

llOS-1 

9S3 

59  4 

4-r)4 

0-329 

0-602 

15-30 

9-72 

5-43 

1075-9 

107-6 

43-4 

7-20 

0-171 

0  674 

1-2-36 

9-26 

6-23 

1021-4 

157-1 

72-7 

3-5S 

0-716 

0-477 

12-&9 

S-44 

6-82 

517-2 

73-3 

38  9 

197 

0-146 

— 

— 

8-56 

6-11 

— 

122-6 

63-4 

— 

0-345 

Acicia 

Fir     - 

Hornbeam 

Birch 

Beech 

Oak    - 

Hohu-Oak 

Find  - 

Svramoro  - 

Asli    - 

Al<ier 

Aspen 

Maple 

Poplar 

Elm   - 


0  297 
0-6IS 
1-063  = 
0  752; 

0-406 
0-196  : 
0-610  j 
0-408  1 
0175 
0-414  I 
0-371  i 
0-214  i 
0-366  I 


L  refers  to  rod.s  cut  lengthwise  with  the  grain, 
K  to  those  cut  in  a  direction  radial,  and 
T  to  those  tangential  to  the  annu.il  rings. 


ELDER.  (Sambucus  nigra.  Sureau,  Fr.  ;  Ilohlundcr,  Germ.)  Pith  balls  for  elec- 
trical purposes  are  manufactured  from  the  pith  of  the  elder  tree,  dried.  The  wood  is  em- 
ployed for  inferior  turnery  work,  for  weavers'  shuttles,  netting  pins,  and  shoemakers'  pegs. 
Its  "elasticity  and  strength  render  it  peculiarly  fitted  for  the.-e  latter  purposes. 

ELECTRIC  CLOCKS.  The  apiilicationof  electricity  as  a  motive  power  to  clocks,  and 
as  a  means  of  transmitting  synchronous  signals  or  time,  is  naturally  intimately  connected 
with  the  attempts  (not  yet  realized  in  an  economic  point)  to  apply  it  as  a  motive  power  to 
machinery,  and  with  its  application,  so  fully  realized,  (see  article  Ei.ECTr.o-TKLEGRArnY,)  to 
telegraphy  proper ;  and  it  has  grown  up  side  by  side  with  the  latter.  Prof.  Wheatstone's 
attention  was  directed  to  it  in  the  very  early  days  of  telegraphy.  Without  entering  upon 
the  history  of  electric  clocks,  it  will  suffice  to  describe  two  [irinciples  on  which  they  have 
been  constructed,  and  which  are  best  known, — Bain's  and  Shepherd's.  In  the  former,  elec- 
tricity maintains  the  pendulum  in  motion,  and  the  pendulum  drives  the  clock -train ;  in  the 
latter,  the  motion  of  the  pendulum  is  maintained  by  electricity,  but  the  clock-train  is  driven 
by  distinct  currents,  sent  to  it  by  means  of  pendulum  contacts. 


ELECTEIO  CLOCKS. 


481 


250 


The  bob  of  Bain's  pendulum  consists  of  a  coil  of  wire,  wound  on  a  bobbin  with  a  hol- 
low centre.  The  axis  of  the  bobbin  is  horizontal.  Bar  magnets,  presenting  similar  poles, 
are  fixed  on  each  side  of  the  coil,  in  such  a  position  that,  as  the  pendulum  oscillates  right 
and  left,  the  poles  on  either  side  may  enter  the  coil  of  wire.  It  is  one  of  the  laws  of  elec- 
tric currents,  when  circulating  in  a  helix,  or  spiral,  or  coil,  or  even  in  a  single  ring,  that 
each  face  of  the  coil  presents  the  characters  of  a  magnetic  pole ;  of  a  south  pole  if  the  cur- 
rent circulates  in  the  direction  in  which  the  hands  of  a  watch  move  ;  of  a  north  pole,  if  it 
circulates  in  the  reverse  direction.  Things  are  so  arranged  in  Bain's  pendulum,  that  a  bat- 
tery current  is  alternately  circulating  in  and  cut  off  from  the  coil.  When  the  current  is 
circulating,  the  coil  has  the  character  of  a  magnet,  with  a  north  end  and  a  south  end  ;  if 
the  permanent  magnets  present  north  poles,  the  north  end  of  the  coil-bob  will  be  repelled 
from  one  of  the  magnets,  while  its  south  end  will 
be  attracted  by  the  other  magnet.  This  consti- 
tutes the  impulse  or  maintaining  power  in  one 
direction.  Now  the  connections  are  such  that,  when 
the  arc  of  vibration  is  complete  and  the  pendulum 
ready  for  the  return  vibration,  the  pendulum  rod 
pushes  aside  a  golden  slide,  by  which  the  electric 
circuit  had  been  completed,  and  the  current  is  cut 
off;  the  pendulum  is  thus  able  to  make  its  return 
vibration  by  mere  gravity.  It  starts  to  repeat  the 
above  operations  by  mere  gravity  ;  but,  ere  it  com- 
pletes the  arc,  the  rod  pushes  back  the  slide,  and 
again  completes  the  electric  circuit,  and  gives  rise  to 
a  second  impulse,  and  so  on.  A  small  amount  of 
magnetic  attraction  is  sufficient  to  supply  the  neces- 
sary amount  of  maintaining  power.  One  pair  of  zinc- 
copper,  buried  in  the  moist  earth,  has  been  found 
ample. 

In  an  ordinary  clock,  the  train  is  carried  by  a 
weight  or  by  a  spring,  and  the  time  is  regulated  by 
the  pendulum.  In  Bain's  the  time  is  regulated  and 
the  train  is  driven  by  the  pendulum.  The  rod  hangs 
within  a  crutch  in  the  usual  way ;  the  crutch  carries 
pallets  of  a  particular  kind,  acting  in  a  scape-wheel ; 
and  from  the  latter,  the  motion  is  transmitted  to  a 
train  of  the  usual  character,  but  much  lighter.  For 
large  clocks,  Mr.  Bain  proposes  a  modification  of  the 
slide,  which  shall  invert  the  current  at  each  oscilla- 
tion, so  as  to  have  attraction  as  a  maintaining  power 
in  both  oscillations.  The  general  arrangement  of 
the  pendulum  is  shown  in  ^^.  250.  b  is  the  pendu- 
lum bob,  with  its  coil  of  wire,  the  ends  of  which  pass 
up  on  either  side  of  the  rod.  z  and  c  are  the  battery 
plates,  with  their  attached  wires  d  and  d'.  The  ar- 
rows show  the  course  of  the  voltaic  current  from  the 
plate  c  by  the  wire  d',  thence  down  the  pendulum 
rod  by  the  right  hand  wire,  through  the  coil  b,  up 
by  the  wire  on  left  side  of  rod,  then  by  the  wire  c, 
along  the  slide  at  e,  and  by  the  wire  d  to  the  zinc 
plate  z.  When  the  slide  e  is  in  position,  the  circuit 
is  complete,  and  the  bol)  is  attracted  by  the  n  pole 
of  one  of  tlie  magnets,  and  repelled  by  the  n  pole 
of  the  other.  When  the  slide  is  displaced,  the  at- 
traction ceases,  and  the  pendulum  is  left  to  the  mere 
action  of  gravity. 

Shepherd's  electric  clock  has  a  remontoir  escapement.  There  is  no  direct  connection 
between  the  electric  force  and  the  pendulum,  or  between  the  pendulum  and  the  clock-train. 
Tlie  attractive  power,  derived  from  the  electric  current,  is  simply  employed  to  raise  the  same 
small  weight  to  the  same  height ;  and  the  clock-train  is  carried  by  the  attractive  force  de- 
rived from  electric  currents,  whose  circuits  are  completed  by  the  pendulum  touching  contact 
springs.  The  pendulum  is  thus  protected  from  the  influence  of  change  in  the  force  of  the 
current,  or  from  irregular  resistances  in  the  train.  Fig.  251  is  a  poi'spectivc  view  of  this 
pendulum,  with  batteries  s  z  attached,  and  the  clock  connections  and  those  of  its  batteries 
s  z  .1  z  shown.  The  electricity  leaves  the  pendulum  battery  by  the  wire  a,  and  returns  to  it 
by  the  wire  f.  There  is  only  one  break  in  this  circuit,  namely,  at  e,  whicli  is  a  slender  spring 
faced  with  platinum,  that  is  in  contact  with  platinum  on  the  pendulum  at  the  extreme  of  its 
Vol.  III.— 31 


483 


ELECTRIC  CLOCKS. 


right  vibration,  but  at  no  other  time.  The  wire  a  reaches  the  pendulum  from  the  battery 
by  the  coils  b,  the  plate  C,  and  the  frame  d  ;  the  wire  r  goes  direct  from  the  spring  f,  to  the 
zinc  z.  From  this  arrangement,  it  happens  that  every  time  the  contact  at  e  is  completed, 
the  iron  core,  of  which  the  ends  n  s  are  visible,  contained  within  the  coils  b,  becomes  a 


magnet,  and  when  the  contact  at  e  is  broken,  the  magnetism  ceases.  The  poles  n  s  have, 
therefore,  a  power  alternately  to  attract  and  to  release  «,  which  is  a  plate  or  armature  of 
soft  iron,  moving  on  an  axis,  as  shown  in  the  figure,  and  to  which  is  attached  a  bar  b,  with 
a  counterpoise  i.  We  have  said  that  the  office  here  of  the  electric  force,  is  merely  to  raise 
a  weight ;  the  fall  of  the  weight  maintains  the  pendulum  in  motion.  When  the  armature  a 
is  attracted,  the  lever  b  is  raised  ;  this  raises  the  wire  c  into  a  horizontal  position,  and  its 
other  part  d  into  a  vertical  position  ;  the  latter  is  caught  and  retained  by  the  latch  or  detent 


ELECTRIC  CLOCKS.  483 

c ;  so  that  when  the  magnetic  attraction  ceases,  the  counterpoise  i  descends  with  the  lever 
b  ;  and  so  the  armature  a  leaves  the  electro-magnet  n  s.  But  the  wire  d  remains  vertical, 
and  its  other  part  with  the  small  weight  c  remains  horizontal.  Now,  when  the  pendulum 
makes  its  left  hand  oscillation,  the  point  of  the  screw  /  impinges  upon  the  stem  </,  and  car- 
ries it  a  little  to  the  left ;  this  raises  the  detent  e,  and  liberates  the  piece  d  c,  which  descends 
into  its  original  position  by  gravity  ;  the  small  ball  c  adds  to  its  weight.  In  descending,  the 
vertical  piece  c  strikes  against  the  point  of  the  screw  A,  and  gives  a  small  impulse  to  the 
pendulum  p.  The  ball  c  is  not  larger  than  a  pea,  and  its  fall  is  not  an  eighth  of  an  inch  ; 
but  the  impact  is  sufficient  to  keep  the  pendulum  in  motion  ;  and  it  is  constant,  being  this 
same  body  falling  through  the  same  space ;  and  is  independent  of  any  variation  in  the 
battery  power,  which  latter  is  only  concerned  in  raising  the  ball.  The  arc  of  the  pendulum's 
vibration  is  regulated  by  adjusting  the  small  ball  to  a  greater  or  less  distance  from  the  cen- 
tre. Provision  is  thus  made  for  maintaining  the  pendulum  in  motion,  and  giving  it  an  im- 
pact of  constant  value.  If  this  arrangement  is  in  connection  with  a  compensating  mercurial 
pendulum,  extreme  accuracy  of  time-keeping  is  attained.  The  next  step  is  to  transfer  the 
seconds,  thus  secured,  to  a  dial  or  clock.  The  same  movement  of  the  keeper  a  with  its 
counterpoise  i,  has  sometimes  been  made  to  impart  motion  to  the  seconds  wheel  of  a  clock- 
train  ;  but  more  commonly  the  clock-train  is  distinct,  as  shown  in  the  drawing,  and  is  carried 
by  a  special  electro-magnetic  arrangement,  in  connection  with  separate  batteries,  z  c,  zc,  the 
contacts  of  which  are,  however,  under  the  control  of  the  pendulum.  Insulated  springs,  k 
and  /,  are  fixed  near  the  top  of  the  rod  ;  from  k  a  wire  leads  to  the  silver  s,  of  the  left  hand 
battery  ;  and  from  /  another  wire  leads  to  the  zinc  .?,  of  the  right  hand  battery.  The  other 
metals  of  the  respective  batteries  are  connected  by  a  wire  with  an  electro-magnet  within  the 
clock,  the  other  end  of  the  said  electro  magnet  being  connected  with  the  metal  bed  and 
frame  of  the  pendulum.  When,  therefore,  the  pendulum  oscillates  to  the  right,  the  circuit 
is  completed  at  k ;  and  the  current  of  the  left  hand  battery  circulates  from  s  through  the 
wire  k ;  and  thence  through  the  metal  frame  and  by  the  wire  to  the  clock,  and  so  to  the 
zinc  2.  When  the  oscillation  is  to  the  left  and  /  is  in  contact,  the  riglit  hand  battery  is  in 
action ;  and  the  current  circulates  from  s  through  the  clock,  to  the  metal  frame,  and  thence 
to  /  and  to  the  zinc  z  of  the  battery.  In  one  case,  a  voltaic  current  enters  the  clock  by  the 
wire  shown  below,  and  leaves  it  by  the  upper  wire  ;  and,  in  the  other  case,  it  enters  by  the 
upper  and  leaves  by  the  lower  wire.  There  is  a  double  set  of  electro-magnets  within  the 
clock,  showing  four  poles  in  all ;  there  are  also  two  magnetized  steel  bars,  moimted  see-saw 
fashion,  with  their  poles  alternate,  and  facing  the  four  electro -magnetic  poles.  When  the 
current  enters  the  clock  from  below  or  in  one  direction,  the  bars  oscillate  this  way ;  when  it 
enters  from  above  or  in  the  reverse  direction,  they  oscillate  that  way.  They  are  both  fixed 
at  right  angles  to  and  upon  the  same  axis  ;  which  axis  carries  a  pair  of  driving  pallets,  that 
act  on  a  scape-wheel,  and  so  the  clock-train  is  driven.  It  will  be  seen  at  a  glance,  that  two 
or  more  clocks  may  be  connected  in  the  same  circuit,  as  readily  as  one ;  it  being  merely 
necessary  in  such  case  to  modify  the  battery  power,  to  correspond  with  the  work  to  be  done. 
For  instance,  three  such  clocks  have  been  going  for  several  years  at  Tonbridge  by  the  same 
pendulum  ;  several  are  actuated  in  like  manner  at  the  Royal  Observatory,  Greenwich.  Nor 
is  it  necessary  that  the  clocks  should  be  in  the  same  room  with  the  pendulum,  or  in  the  same 
building,  or  even  in  the  same  parish.  All  the  clocks  above  referred  to,  are  variously  dis- 
tributed ;  and  one  of  the  Ol^servatory  clocks  is  six  miles  distant  from  its  pendulum,  being 
at  the  London  Bridge  Station  of  the  South-Eastern  Railway. 

In  cases  where  it  has  not  Vjcen  found  convenient  to  drive  the  clock -train,  especially  in 
the  case  of  a  public  one,  the  movement  of  which  is  heavy,  great  advantage  has  been  de- 
rived for  regulating  the  oscillations  of  the  pendulum  of  the  large  clock,  by  means  of  elec- 
tric currents,  imder  the  control  of  a  standard  pendulum.  Mr.  Jones  has  adopted  this 
method,  and  it  is  likely  to  meet  with  much  favor.  The  turret-clock,  under  this  arrange- 
ment, is  driven  by  weights  in  the  usual  way,  and  the  time  is  regulated  by  a  pendulum.  Tlie 
bob  of  the  pendulum  is  placed  under  a  condition  analogous  to  that  of  Bain's,  {fg.  250,)  the 
permanent  magnet,  however,  being  attached  to  the  pendulum,  and  the  electro-magnet  fixed 
facing  it.  If  currents  are  made  to  circulate  synchronously  in  the  latter,  by  means  of  a 
standard  pendulum,  the  oscillations  of  the  pendulum  of  the  turret-clock  are  constrained  to 
accord  with  those  of  the  standard,  and  a  very  perfect  system  of  time-keeping  is  obtained. 
This  is  practised  at  Liverpool,  and  has  just  been  introduced  at  Greenwich. 

Under  the  above  arrangements  the  clock  is  controlled  by  the  standard  pendulum  second 
by  second,  and  the  two  keep  time  together  throughout  the  day.  There  arc  cases  in  which 
it  is  sufficient,  and  also  more  convenient,  to  correct  a  clock  once  a  day  only  by  means  of  a 
telegraph  signal  transmitted  from  a  standard  clock.  This  is  managed  in  several  ways. 
There  is  a  clock  at  the  Telegraph  Office  in  the  Strand  ;  a  good  regulator,  adjusted  to  gain  a 
second  or  two  during  the  twenty  four  hours,  and  to  stop  at  1  p.  m.  A  telegraph  signal  is 
sent  from  the  Royal  Observatory  precisely  at  1,  that  drops  a  time-ball  at  the  Strand  office, 
which,  in  falling,  starts  the  clock.  At  Ashford,  seventy-three  miles  from  Greenwich,  tliere 
is  an  electric  clock  which  has  a  gaining  rate,  and  which  is  so  constructed  that  the  battery 


484 


ELECTRIC  CLOCKS. 


circuit  is  opened  at  1  o'clock  by  means  of  pins  and  springs  attached  to  the  movement,  and 
the  clock  therefore  stops.  At  1  p.  m.,  Greenwich  mean  time,  a  signal  is  sent  through  the 
Ashford  clock  from  the  Royal  Observatory,  which  starts  it  at  once  at  true  time.  At  the 
Post  Office,  Lombard  Street,  there  is  a  clock  which,  in  the  course  of  the  twenty-four  hours, 
raises  a  weight.  At  noon  a  telegraph  signal  is  sent  from  Greenwich,  which  passes  through 
an  electro-magnet ;  the  latter  attracts  an  armature  of  soft  iron  and  liberates  the  ball,  which 
falls,  and  in  falling  it  encounters  a  crutch,  or  lever,  attached  to  the  seconds'  hand,  and 
thrusts  it  this  way  or  that,  as  the  case  may  be ;  but  so  as  to  bring  it  to  sixty  seconds  on  the 
dial,  and  thus  to  set  the  clock  right. 

Intermediate  between  the  one  method  of  sending  a  signal  every  second  to  regulate  a 

clock,  and  the  other  method  of  sending  it  once  a 
day,  we  have  the  following  arrangement  of  Bain's 
for  sending  it  once  an  hour.  Fig.  252  shows  the 
arrangement,  with  part  of  the  dial  removed,  to  show 
the  position  of  the  electro-magnet.  The  armature 
is  below  ;  it  carries  a  vertical  stem,  terminating  above 
in  a  fork.  Its  ordinary  position  is  shown  by  the  dot- 
ted lines.  The  minute  hand  (partly  removed  from 
the  cut)  carries  a  pin  on  its  back  surface.  When  the 
hand  is  near  to  sixty  minutes,  and  an  electric  current 
is  sent  through  the  magnet,  the  armature  is  attracted 
upwards  and  the  fork  takes  the  position  shown  by 
the  full  lines  at  the  top  of  the  dial,  and,  in  doing  so, 
it  encounters  the  pin  and  forces  the  hand  into  the 
vertical  position,  and  sets  the  clock  to  true  time,  pro- 
viding tlie  signal  comes  from  a  standard  clock,  or  is 
sent  by  hand  at  true  time.  A  dial  of  moderate  char- 
acter keeps  so  near  to  time,  that  once  or  twice  a  day 
would  be,  for  all  common  purposes,  often  enough  to 
correct  it. 

Fig.  253  is  an  arrangement  of  Bain's,  by  which  a  principal  clock,  showing  seconds,  sends 
electric  currents  at  minute  intervals  to  other  clocks,  and  causes  the  hand  to  move  minute  by 
minute,  a  is  a  voltaic  battery  ;  b  is  the  principal  clock,  which  may  be  an  electric  clock  or 
not,  at  pleasure  ;  g  and  h  are  two  out  of  many  subordinate  clocks.  The  seconds'  hand  of 
the  principal  clock  completes  a  voltaic  circle  twice  (for  the  case  of  two  clocks)  during  the 
minute ;  at  the  30  seconds  for  the  clock  g,  and  at  the  60  seconds  for  the  clock  h.  The 
clock  H  shows  time  in  leaps  from  one  minute  to  the  next ;  and  the  clock  g  from  one  half 
minute  to  the  next  half  minute.  As  many  more  contacts  per  minute  may  be  provided  for 
the  seconds'  hand  of  the  prime  clock  as  there  are  subordinate  clocks. 

253 


Next  akin  to  the  time  signals  above  described,  and  which  act  automatically  upon  clocks, 
either  to  drive  the  clock  train  or  to  correct  the  clock  errors,  are  mere  time  signals,  which 
are  extensively  distributed  throughout  the  country  by  the  ordinary  telegraph  wires,  and  are 
looked  for  at  the  various  telegraph  stations,  in  order  to  compare  the  office  dials  with  Green- 
wich mean  time,  and  to  make  the  necessary  correction ;  they  are  also  redistributed  by  hand 
the  fiKviiont  thoy  appeal',  through  sub-districts  branching  from  junction  stations.     Large 


ELEOTKICITY. 


485 


black  balls,  hoisted  in  conspicuous  stations,  are  also  dropped  daily  by  electric  currents  in 
various  places,  for  the  general  information  of  the  public,  or  of  the  captains  of  ships. — 
C.  V.  w. 

ELECTRICITY  for  Blasting  in  Mines  and  Quarries.  Professor  Hare  was  the  first  who 
entertained  this  idea,  but  Mr.  Martin  Roberts  devised  the  following  process  : — In  order  not 
to  be  called  upon  to  malie  afresh  a  new  apparatus  for  each  explosion,  Mr.  Roberts  invented 
cartridges,  which  may  be  constructed  beforehand.  With  this  view,  two  copper  wires  are 
procured,  about  a  tenth  of  an  inch  in  diameter,  and  three  yards  in  length,  well  covered  with 
silk  or  cotton  tarred,  so  that  their  insulation  may  be  very  good.  They  are  twisted  together 
{fiff.  254)  for  a  length  of  six  inches,  care  being  taken  to  leave  their  lower  extremities  free, 
for  a  length  of  about  half  an  inch,  (separating  them  about  half  an  inch,)  from  which  the 
insulating  envelope  is  removed,  in  order  to  stretch  between  them  a  fine  iron  wire,  after  hav- 
ing taken  the  precaution  of  cleaning  them  well.  The  upper  extremities  of  the  two  copper 
wires  are  likewise  separated,  in  order  to  allow  of  their  being  placed  respectively  in  commu- 
nication with  the  conductors,  that  abut  upon  the  poles  of  a  pile.  The  body  of  the  car- 
tridges is  in  a  tin  tube,  three  inches  long  and  three-quarters  of  an  inch  in  diameter,  the 
solderings  of  which  are  very  well  made,  in  order  that  it  may  be  perfectly  impermeable  to 
water.  A  glass  tube  might  equally  well  be  employed,  were  it  not  for  its  fragility,  which  has 
caused  a  tin  tube  to  be  preferred.  The  system  of  copper  wires  is  introduced  into  the  tube, 
fixing  them  by  means  of  a  stem  that  traverses  it  at  such  a  height  that  the  fine  iron  wire  is 
situated  in  the  middle  of  the  tin  tube,  so  arranged  that  the  ends  of  the  copper  wire  do  not 
anywhere  touch  the  sides  of  the  tube,  (Jiff.  255.)  The  cork  is  firmly  fixed  at  the  upper 
extremity  of  the  tube  with  a  good  cement.  Mr.  Roberts  recommends  for  this  operation,  a 
cement  composed  of  one  part  of  beeswax  and  two  parts  of  resin ;  the  tube  is  then  filled 
with  powder  by  its  other  extremity,  which  is  likewise  stopped  with  a  cork,  which  is  cement- 


254 


256 


255 


ed  in  the  same  manner.  Fig.  256  indicates  the  manner  in  which  the  car- 
tridge is  placed  in  the  hole,  after  having  carefully  expelled  all  dust  and 
moisture  ;  care  must  be  taken  that  the  cartridge  is  situated  in  the  middle 
of  the  charge  of  powder  that  is  introduced  into  the  hole.  Above  the  powder 
is  placed  a  plug  of  straw  or  tow,  so  as  to  allow  between  it  and  the  powder 
a  small  space  filled  with  air ;  and  above  the  plug  is  poured  dry  sand,  until 
the  hole  is  filled  with  it.  The  two  ends  of  the  copper  wires  that  come  out 
of  the  cartridge  are  made  to  communicate  with  the  poles  of  the  pile,  by 
means  of  conductors  of  sufficient  length,  that  one  may  be  protected  from  all  dangers  arising 
from  the  explosion  of  the  mine. 

M.  RuhinkorfT,  and  after  him,  M.  Verdu,  have  successfully  tried  to  substitute  the  induc- 
tion spark  for  the  incandescence  of  a  wire,  in  order  to  bring  about  the  ignition  of  the  ])o\v- 
der.  This  process,  besides  the  consideraijle  economy  that  it  presents — since,  instead  of  from 
fifteen  to  twenty  Bunscn's  pairs,  necessary  for  causing  the  ignition  of  the  wire,  it  requires 
but  a  single  one  for  producing  the  induction  spark — possesses  the  advantages  of  being  less 


48G  ELECTRIC  LIGHT. 

susceptible  of  derangement.  Only  it  was  necessary  to  contrive  a  plan  to  bring  aVioiit  the 
ignition  of  the  powder ;  in  fact,  it  happens,  that  when  by  the  effect  of  the  length  of  the 
coiuiuc-tors  that  abut  upon  the  mine,  the  circuit  presents  too  great  a  resistance,  tiie  induc- 
tion spark  is  able  to  pass  through  the  powder  without  inflaming  it.  M.  Ruhmkorff'  has  con- 
ceived the  happy  idea  of  seeking  for  a  medium,  which,  more  easily  inflammable  by  the 
spai'k,  may  bring  about  the  ignition  of  the  powder  in  all  possible  condition.s.  He  found  it 
in  Statham's  fusees,  which  are  prepared  by  taking  two  ends  of  copper  wire  covered  with 
ordinary  gutta  percha;  they  are  twisted,  [f(j.  257,)  and  the  ends  are  bent  so  as  to  make 
them  enter  into  an  envelope  of  vulcanized  (sulphured)  gutta  percha,  which  has  been  cut  and 
drawn  off  from  a  copper  wire  that  had  been  for  a  long  time  covered  with  it.  Upon  this 
envelope  a  sloping  cut,  a,  b,  is  formed  ;  and  after  having  maintained  the  extremities  of  the 
copi)er  wires  at  about  the  eighth  of  an  inch  from  each  other,  their  points  are  covered  with 
fulminate  of  mercury,  in  order  to  render  the  ignition  of  the  powder  more  easy.  The  cut  is 
filled  with  powder,  and  the  whole  is  wrapped  round  with  a  piece  of  caoutchouc  tube,  c,  d,  or 
else  it  is  placed  in  a  cartridge  filled  with  powder.  ^ 

In  the  Statham  fusees,  it  is  the  sulphide  (sulphuret)  of  copper  adhering  to  the  wire,  pro- 
duced by  the  action  of  the  vulcanized  gutta  percha  which  is  removed  from  the  copper  wire 
that  it  covered,  which,  by  being  inflamed  under  the  action  of  the  induction  spark,  brings 
about  an  explosion.  But  it  is  necessary  to  take  care  when  the  fusee  has  been  prepared,  as 
we  have  pointed  out,  to  try  it  in  order  to  regulate  the  extent  of  the  solution  of  continuity. 
It  might,  in  fact,  happen  that  while  still  belonging  to  the  same  envelope  of  a  copper  wire, 
the  sheath  of  a  vulcanized  gutta  percha  with  which  the  fusee  is  furnished,  may  be  more  or 
less  impregnated  with  sulphide  of  copper ;  now,  if  the  sulphide  of  copper  is  in  too  great 
quantity,  it  becomes  too  good  a  conductor,  and  prevents  the  spark  being  produced  ;  if,  on 
the  contrary,  it  is  not  in  a  sufficiently  large  quantity,  it  does  not  sufficiently  faciliate  the 
discharge. 

The  fii-st  trials  on  a  large  scale  of  the  application  of  the  process  that  we  just  described, 
were  made  with  Ruhmkorff's  induction  apparatus,  by  the  Spanish  colonel,  Yerdu,  in  the 
workshops  of  M.  Ilerkman,  manufacturer  of  gutta  percha  covered  wire,  at  La  Yillettc,  near 
Paris.  Experiments  were  made  successively  upon  lengths  of  wire  of  400,  600,  1,000, 
5,000,  and  up  to  26,000  metres,  (of  3*28  feet ;)  and  the  success  was  always  complete, 
whether  with  a  circuit  composed  of  two  wires,  or  replacing  one  of  the  wires  by  the  earth  ; 
two  ordinary  Bunsen's  pairs  were  sufficient  for  producing  the  induction  spark  with  Ruhm- 
korff's apparatus.  Since  his  first  researches  with  M.  Ruhmkorff",  M.  Yerdu  has  applied  him- 
self to  fresh  researches  in  Spain  ;  and  he  was  satisfied,  by  many  trials,  that  of  all  explosive 
substances,  not  any  one  was  nearly  so  sensitive  as  fulminate  of  mercury  ;  only,  in  order  to 
avoid  the  danger  that  arises  from  the  facility  of  explosion  of  this  compound,  he  takes  the 
precaution  of  introducing  the  extremity  of  the  fusees  into  a  small  gutta  percha  tube,  closed 
at  the  end.  After  having  filled  with  powder  this  species  of  little  bos,  and  having  closed  it 
hermetically,  the  fusees  may  be  carried  about,  may  be  handled,  may  be  allowed  to  fall,  and 
even  squeezed  rather  hard,  without  danger.  The  elastic  and  leather-like  nature  of  gutta 
percha,  which  has  been  carefully  softened  a  little  at  the  fire,  preserves  the  fulminate  from 
all  chance  of  accident.  We  may  add,  that  with  a  simple  Bunsen's  pair,  and  by  means  of 
Ruhmkorff's  induction  apparatus,  M.  Yerdu  has  succeeded  in  producing  the  siifndtaneous 
explosion  of  six  small  mines,  interposed  in  the  same  circuit  at  320  yards  from  the  appa- 
ratus. He  has  not  been  beyond  this  limit ;  but  he  has  sought  for  the  means  of  acting  indi- 
rectly upon  a  great  number  of  mines,  by  distributing  them  into  groups  of  five,  and  by 
interposing  each  of  these  groups  in  a  special  circuit.  The  fusees  of  each  group  are  made 
to  communicate  by  a  single  wire,  one  of  the  extremities  of  which  is  buried  in  the  ground, 
and  whose  other  extremity  is  near  to  the  apparatus.  On  touching  the  induction  apparatus 
successively  with  each  of  the  free  ends  that  are  held  in  the  hand,  which  requires  scarcely  a 
second  of  time,  if  there  are  four  wires,  that  is  to  say,  four  groups  and  consequently  twenty 
mines,  twenty  explosions  are  obtained  simultaneously  at  considerable  distances.  There  arc 
no  limits  either  to  the  distance  at  which  the  explosion  may  take  place,  or  to  the  number  of 
mines  that  may  thus  be  made  to  explode. 

ELECTRIC  LKiHT.  Yarious  attempts  have  been  made,  from  time  to  time,  to  employ 
electricity  as  an  illuminating  power  ;  but  hitherto  without  the  desired  success.  The  voltaic 
battery  has  been  employed  as  the  source  of  electricity,  and  in  nearly  all  the  arrangements, 
the  beautiful  arc  of  light  produced  between  the  poles,  from  the  points  of  the  hardest  char- 
coal, has  been  the  illuminating  source.  One  of  the  great  difl[icultics  in  applying  this  agent 
arises  from  the  circumstance  that  there  is  a  transference  of  the  charcoal  from  one  pole  to 
the  other,  and  coivsequently  an  alteration  in  the  distance  between  them.  This  gives  rise  to 
consideral)le  variations  in  the  intensity  and  color  of  the  light,  and  great  want  of  steadiness. 
Various  arrangements,  many  of  them  exceedingly  ingenious,  have  been  devised  to  over- 
come these  difficulties. 

The  most  simple  of  the  apparatus  which  has  been  devised  is  that  of  Jlr.  Staite,  which 
has  been  modified  by  M.  Archereau.     Two  metal  columns  or  stems,  to  which  any  desired 


ELECTRIC  LIGHT.  487 

form  can  be  given,  are  connected  together  by  three  cross  pieces,  so  as  to  form  one  solid 
frame ;  one  of  these  cross  pieces  is  metallic ;  it  is  the  one  which  occupies  the  upper  part 
of  the  apparatus  ;  the  others  must  be  of  wood.  These  latter  serve  as  supports  and  points  of 
attachment  to  a  long  bobbin  placed  parallel  to  the  two  columns  and  between  them,  and  which 
must  be  made  of  tolerably  thick  wire,  in  order  that  the  current,  in  traversing  it  without 
melting  it,  may  act  upon  a  solt  iron  rod  placed  in  the  interior  of  the  bobbin.  This  iron  rod 
is  soldered  to  a  brass  stem  of  the  same  calibre,  and  of  the  same  length,  carrying  at  its  free 
extremity  a  small  pulley.  On  the  opposite  side  the  iron  carries  a  small  brass  tube,  with 
binding  screws,  into  which  is  introduced  one  of  the  carbons,  when  the  entire  rod  has  been 
placed  in  the  interior  of  the  bobbin.  Then  a  cord  fixed  to  the  lower  cross  piece,  and  roll- 
ing over  a  pulley  of  large  diameter,  is  able  to  serve  as  a  support  to  the  movable  iron  rod, 
running  in  the  groove  of  the  little  pulley.  For  this  purpose,  it  only  i-etiuires  that  a  coun- 
terpoise placed  at  the  end  of  the  cord  shall  be  enabled  to  be  in  equilibrio  with  it.  The 
metal  cross  piece  which  occupies  the  upper  part  of  the  apparatus,  carries  a  small  brass  tube, 
which  descends  perpendicularly  in  front  of  the  carbon  tliat  is  carried  by  the  electro-mag- 
netic stem,  and  into  which  is  also  introduced  a  carbon  crayon.  By  means  of  a  very  simple 
adjustment,  this  tube  may  besides  be  easily  regulated,  both  for  its  height  and  for  its  direc- 
tion ;  and  consequently  the  two  carbons  may  be  placed  very  exactly  above  one  another. 
The  apparatus  being  adjusted,  we  place  one  of  the  two  metal  columns  of  the  apparatus  in 
connection  with  one  of  the  poles  of  the  pile,  and  cause  the  other  pole  to  abut  upon  the  cop- 
per wire  of  the  bobbin,  (one  end  of  which  is  soldered  upon  its  socket.)  The  current  then 
passes  from  the  bobbin  to  the  lower  carbon  by  the  rod  itself  that  supports  it,  and  passing 
over  the  interval  separating  the  two  carbons,  it  arrives  at  the  other  pole  of  the  pile  by  the 
upper  cross  piece  of  the  apparatus  and  the  metal  column,  to  which  one  of  the  conducting 
wires  is  attached. 

So  long  as  the  current  is  passing  and  producing  light,  the  bobbin  reacts  upon  the  iron 
of  the  electro-magnet  rod,  which  carries  the  lower  carbon  and  attracts  it  on  account  of  the 
magnetic  reaction  that  solenoids  exercise  over  a  movable  iron  in  their  interior.  It  is  this 
which  gives  to  the  carbons  a  separation  sufficient  for  the  luminous  effect. 

But  immediately  the  current  ceases  to  pass,  or  is  weakened,  in  consequence  of  the  con- 
sumption of  the  carbons,  this  attraction  ceases,  and  the  movable  carbon,  acted  on  by  the 
counterpoise,  is  found  to  be  drawn  on  and  raised  until  the  current  passes  again  ;  equilibrium 
is  again  established  between  the  two  forces,  and  the  carbons  may  be  employed  again.  Thus, 
in  proportion  as  the  light  tends  to  decrease,  the  counterpoise  reacts ;  and  this  it  is  that 
always  maintains  the  intensity  of  the  light  equal. 

M.  Breton  has  an  apparatus  which  differs  somewhat  from  the  above,  and  M.  Foucault 
has  also  devised  a  very  ingenious  modification. 

M.  Duboscq  has  made  by  far  the  most  successful  arrangement,  for  a  description  of  which 
we  are  indebted  to  De  la  Rive's  Treatise  on  Electricity.,  translated  by  C.  V.  Walker. 

The  two  carbons,  between  which  the  light  is  developed,  burn  in  contact  with  the  air,  and 
shorten  at  each  instant ;  a  mechanism  is  consequently  necessary,  which  brings  them  near  to 
each  other,  proportionally  to  the  progress  of  the  combustion  ;  and  since  the  positive  carbon 
suffers  a  more  rapid  combustion  than  the  negative,  it  must  travel  more  rapidly  in  face  of 
this  latter ;  and  this  in  a  relation  which  varies  with  the  thickness  and  the  nature  of  the  car- 
bon.  The  mechanism  must  satisfy  all  these  exigencies.  The  two  carbons  are  unceasingly 
solicited  towards  each  other,  the  lower  carbon  by  a  spii-al  spring,  that  causes  it  to  rise,  and 
the  upper  carbon  by  its  weight,  which  causes  it  to  descend.    The  same  axis  is  common  to  them. 

The  galvanic  current  is  produced  by  a  Bunsen's  pile  of  from  40  to  50  elements :  it 
arrives  at  the  two  carbons,  as  in  apparatus  already  known,  passing  through  a  hollow  electro- 
magnet, concealed  in  the  column  of  the  instrument.  When  the  two  carbons  are  in  contact, 
the  circuit  is  closed,  the  electro-magnet  attracts  a  soft  iron,  placed  at  the  extremity  of  a 
lever,  which  is  in  gear  with  an  endless  screw.  An  antagonist  spring  tends  always  to  unwind 
the  screw  as  soon  as  a  separation  is  produced  between  the  two  carbons  ;  if  it  is  a  little  con- 
siderable, the  current  no  longer  passes,  the  action  of  the  spring  becomes  predominant,  the 
screw  is  unwound,  and  the  carbons  approach  each  other  until,  the  current  again  commenc- 
ing to  pass  between  the  two  carbons,  the  motion  that  drew  them  towards  each  other  is 
relaxed  in  proportion  to  the  return  of  the  predominance  of  the  electricity  over  the  spring ; 
the  combustion  of  the  carbons  again  increases  their  distance,  and  with  it  the  superior  action 
of  the  spring ;  hence  follows  iigain  the  i)redoniinance  of  the  spring,  and  so  on.  These  are 
alternatives  of  action  and  reaction,  in  which  at  one  time  the  sj)riiig,  at  another  time  the 
electricity,  has  the  predominance.  On  an  axis,  common  to  the  two  carl)ons,  arc  two  i)ul- 
leys :  one,  the  diameter  of  which  may  l)e  varied  at  pleasure,  communicates  by  a  cord  with 
the  rod  that  carries  the  lower  carbon,  which  corresponds  with  the  positive  pole  of  the  pile ; 
the  other,  of  invariable  diameter,  is  in  connection  with  the  upper  or  negative  carbon.  The 
diameter  of  the  pulley,  capable  of  varying  proportionately  to  the  using  of  the  carl  ion,  with 
which  it  is  in  communication,  may  ha  increased  from  three  to  five.  The  object  of  this 
arrangement  is  to  preserve  the  luminous  point  at  a  convenient  level,  whatever  may  be  the 


488 


ELECTRIC  LIGHT. 


thickness  or  the  nature  of  the  carbons.  It  is  only  necessary  to  know  that,  at  each  change 
of  kind  or  volume  of  the  carbon,  the  diameter  of  the  pulley  must  be  made  to  vary.  This 
variation  results  from  that  of  a  movable  drum,  communicating  with  six  levers,  articulated 
near  the  centre  of  the  sphere  ;  the  movable  extremity  of  the  six  arms  of  the  lever  carries 
a  small  pin,  which  shdes  in  cylindrical  slits.  These  slits  are  obliqvie  in  respect  of  the 
sphere  ;  they  form  inclined  planes.  A  spiral  spring  always  rests  upon  the  extremity  of  the 
levers ;  so  that,  if  the  inclined  planes  are  turned  towards  the  right,  the  six  levers  bend 

258 


towards  the  centre,  and  diminish  the  diameter.  If,  on  the  contrary,  they  are  turned  towards 
the  left,  the  diameter  increases,  and  with  it  the  velocity  of  the  tran.slation  of  the  carbon, 
which  communicates  with  the  pulley.  We  may  notice,  in  passing,  that  this  apparatus  is 
marvellously  adapted  to  the  production  of  all  the  experiments  of  optics,  even  the  most  deli- 
cate ;  and  that,  in  this  respect,  it  advantageously  supplies  the  place  of  solar  light.  As  it  is 
quite  impossible  to  describe  accurately  the  minute  arrangements  of  this  instrument,  the  let- 
ters of  reference  have  not  been  used  in  the  text. 


ELEOTKO-METALLURGY.  489 

Dr.  Richardson  informs  us,  that  although  Mr.  Grove  calculated,  some  years  ago,  that  for 
acid,  zinc,  wear  and  tear,  &c.,  of  batteries,  a  light  equal  to  1,444  wax  candles  could  be  ob- 
tained for  about  3s.  &d.  per  hour,  the  cost  of  the  light  employed  for  about  five  minutes  at 
Her  Majesty's  Theatre,  as  an  incident  in  the  ballet,  which  was  obtained  by  employing  75 
cells  of  Callan's  battery  of  the  largest  size,  was  said  to  be  £2  per  night,  or  at  the  rate  of 
£20  per  hour.  In  this  calculation  we  expect  we  have  not  a  fair  representation  of  all  the 
conditions.  To  obtain  a  light  for  ten  minutes,  a  battery  as  large  must  be  used  as  if  it  were 
required  to  be  maintained  in  activity  for  hours — and  probably  the  battery  was  charged  anew 
every  evening.  There  can  be  no  doubt  but  the  cost  of  light  or  of  any  other  force  from 
electricity,  with  our  present  means  of  producing  it,  must  be  greatly  in  excess  of  any  of  our 
ordinary  "means  of  producing  illumination.  For  a  consideration  of  this  subject,  see  Elec- 
Tiio-MOTivE  Engines.  Mr.  Grove  proposed  a  light  which  should  be  obtained  from  incan- 
descent platinum,  but  the  objection  to  this  was,  that  after  a  short  period  the  platinum  broke 
up  into  small  particles,  the  electric  current  entirely  disintegrating  the  metal.  Mr.  Way  has 
lately  exhibited  a  very  continuous  electric  light,  produced  from  a  constant  flow  of  mercury 
rendered  incandescent  by  the  passage  of  the  electric  current. 

ELECTRIC  WEAVING.  M.  Bonelli  devised  a  very  beautiful  arrangement,  by  which 
all  the  work  of  the  Jacquard  loom  is  executed  by  an  electro-magnetic  arrangement.  The 
details  of  the  apparatus  would  occupy  much  space  in  the  most  concise  description,  and  as  the 
invention  has  not  passed  into  use,  although  M.  Froment  has  modified  and  improved  the  ma- 
chine, we  must  refer  those  interested  in  the  subject  to  the  full  description  given  in  JDe  la 
Rivers  Treatise  on  Electricity  by  Walker. 

ELECTRO-METALLURGY.  The  art  of  working  in  metals  was  carried  on  exclusively 
by  the  aid  of  fire  until  the  year  1839.  At  that  epoch  a  new  light  dawned  upon  the  subject ; 
considerable  interest  was  excited  in  the  scientific  world,  and  much  astonishment  among  the 
general  public,  by  the  announcement  that  electricity,  under  proper  management,  and  by 
most  easy  processes,  could  supersede  the  furnace  in  not  a  few  operations  upon  metals ;  and 
that  many  operations  with  metals,  which  could  scarcely  be  entertained  under  the  old  con- 
dition of  things,  might  be  placed  in  the  hands  of  a  child,  when  electricity  is  employed  as 
the  agent. 

Public  attention  was  first  directed  to  the  important  discovery  by  a  notice  that  appeared 
in  the  Athenceum  of  May  4,  1839,  that  Professor  Jacobi,  of  St.  Petersburg,  had  "  found  a 
method  of  converting  any  line,  however  fine,  engraved  on  copper,  into  a  relief,  by  galvanic 
process."  Jacobi's  own  account  of  the  matter  was  that,  while  at  Dorpat,  in  February,  1837, 
prosecuting  his  galvanic  investigations,  a  striking  phenomenon  presented  itself,  which  fur- 
nished him  with  perfectly  novel  views.  Official  duties  prevented  his  completing  the  inves- 
tigation, thus  opened  out  to  him,  during  the  same  year ;  and  it  was  not  until  October  5, 
1838,  that  he  communicated  his  discovery,  accompanied  with  specimens,  to  the  Academy 
of  Sciences  at  St.  Petersburg ;  an  abstract  of  which  paper  was  published  in  the  German 
News  of  the  same  place  on  October  30  of  the  same  year.  And  in  a  letter  of  Mr.  Lettsora, 
dated  February  5,  1839,  the  nature  of  the  discovery  is  thus  given  in  the  following  March 
number  of  the  Annals  of  Electricit;/.  Speaking  of  a  recent  discovery  of  Professor 
Jacobi's,  he  says,  "  He  observed  that  the  copper  deposited  by  galvanic  action  on  his  plates 
of  copper,  could  by  certain  precautions  be  removed  from  those  plates  in  perfect  sheets, 
which  presented  in  relief  most  accurately  every  accidental  indentation  on  the  original  plate. 
Following  up  this  remark,  he  employed  an  engraved  copper-plate  for  his  batterv,  caused  the 
deposit  to  be  formed  on  it,  and  removed  it  by  some  means  or  other ;  he  found  that  the  en- 
graving was  printed  thereon  in  relief,  (like  a  wood-cut,)  and  sharp  enough  to  print  from." 
"This  paragraph  does  not  appear  to  have  caught  the  eye  of  the  public  so  readily  as  the  briefer 
note  that  appeared  a  couple  of  months  later  in  the  AthencEum. 

On  May  8,  or  four  days  after  the  appearance  of  the  notice  in  the  Athenceum,  Mr.  Thomas 
Spencer  gave  notice  to  the  Polytechnic  Society  of  Liverpool  that  he  had  a  communication 
to  make  to  the  Society  relative  to  the  application  of  electricity  to  the  arts.  He  sul)sequcntly 
desired  to  communicate  the  result  of  his  discoveries  to  the  British  Association,  whose  meet- 
ing was  at  hand ;  but,  for  some  cause,  which  does  not  appear,  the  communication  was  not 
made ;  and  it  eventually  was  made  public,  as  at  first  proposed,  througli  the  Polytechnic 
Society  of  Liverpool,  on  September  12,  1839.  In  the  mean  time,  namely  on  May  22,  Mr. 
C.  J.  Jordan,  referring  to  the  notice  in  the  Athenmum,  wrote  to  the  Mechanics'  Maffazinc 
that,  at  the  commencement  of  the  summer  of  1838,  he  had  made  "some  experiments  with 
the  view  of  obtaining  impressions  from  engraved  copper-plates  by  the  aid  ol  galvanism." 
His  letter  describing  this  process  appears  in  the  number  for  June  8.  It  occurred  to  him, 
from  wliat  he  had  gathered  from  previous  experience,  that  an  impression  might  be  obtained 
from  an  engraved  surface ;  and  so  it  was,.  "  for  on  detaching  the  precipitated  metal,  tlie 
most  delicate  and  superficial  markings,  from  the  fine  particles  of  powder  used  in  polishing 
to  the  deeper  touches  of  a  needle  or  graver,  exhibited  their  correspondent  impressions  in 
relief  with  great  fidelity." 

Mr.  Spencer,  in  his  communication,  besides  noticing  the  fidelity  with  which  the  traces 


490 


ELECTKO-METALLURGT. 


on  an  original  plate  were  copied,  recorded  the  case  of  a  copper-plate  that  had  become  cov- 
ered with  precipitated  copper,  excepting  in  two  or  three  jilaces,  where  by  accident  some 
drops  of  varnish  had  fallen  ;  whence  it  occurred  to  him,  and  experiment  confirmed  his  con- 
jecture, that  a  plate  of  copper  might  be  varnished,  and  a  design  made  through  the  varnish 
with  a  point,  and  copper  might  be  deposited  upon  tlie  metal  at  the  exposed  part,  and  thus 
a  raised  design  be  procured. 

In  the  F.'iilosophical  Magazine  for  December,  1836,  Mr.  De  la  Eue,  after  describing  a 
form  of  voltaic  battery,  refers  to  the  well-known  condition  on  which  the  properties  of  the 
battery  in  question  mainly  depend,  that  "  tlie  copper-plate  is  also  covered  with  a  coating  of 
metallic  copper,  which  is  continually  being  deposited  ;"  and  he  goes  on  to  describe  that  "so 
perfect  is  the  sheet  of  copper  thus  formed,  that  being  stripped  out,  it  has  the  counterpart 
of  every  scratch  of  the  plate  on  wiiich  it  is  deposited."  Daniell  himself,  whose  battery  is 
here  in  question,  noticed,  as  he  could  not  fail  to  do  in  common  with  all  wlio  had  employed 
his  battery  to  any  extent,  the  same  peculiarities  ;  but  it  does  not  appear  that  either  he  or 
De  la  Kue,  or  any  one  else,  to  whom  the  phenomenon  presented  itself  before  Jacobi,  Jor- 
dan, or  Spencer,  caught  the  idea  of  its  applicability  in  the  arts.  It  would  also  appear  that  the 
impression  came  with  the  greater  vividness  to  the  two  latter  ;  for,  while  but  little  time  seems 
to  have  been  lost  to  them  in  realizing  their  idea,  twenty  long  months  elapsed  between  the 
time  when  the  "  perfectly  novel  views  "  first  presented  themselves  to  Professor  Jacobi,  and 
the  time  when  his  "  well-developed  galvanic  production  "  was  communicated  to  the  Imperial 
Academy  of  Science.  But,  on  the  other  hand,  neither  Mr.  Jordan  nor  Mr.  Spencer  apfjcai;, 
as  far  as  we  are  aware,  to  have  1  ecu  so  sensible  of  the  importance  of  the  results  to  which 
they  had  arrived,  as  to  have  taken  any  steps  to  secure  them  as  an  invention  or  to  publish 
them,  until  their  attention  was  aroused  by  the  previous  publication  of  the  successes  of  Jacobi. 
Jacobi's  "  Galvano-Plastik,"  Smee's  and  also  Shaw's  "  Electro-Metallurgy,"  Walker's 
"  Electrotype  Manipulation,"  four  well-known  woiks  on  the  subject  before  us,  present  the 
different  names  under  which  the  art  is  known  ;  and  from  which  it  is  gathered  that  metals 
may  become,  as  it  were,  plastic  under  the  agency  of  galvanic  electricity,  and  may  be  worked 
and  moulded  into  form.  Voltaic  pairs  are  described  in  general  terms  in  the  article  on 
ELECTr.o-TELEr.r.AriiT.  The  particular  voltaic  pair  which  led  to  the  discoveries  now  before 
us,  here  requires  special  notice  ;  because,  on  the  one  hand,  while  in  use  for  other  purposes, 
it  was  the  instrument  which  first  directed  attention  forcibly  to  the  behavior  of  metals  under 
certain  conditions  of  electric  current ;  and,  on  the  other  hand,  it  has  been  itself  extensively 
used  in  electrotype  operations.  Professor  Daniell  first  described  his  mode  of  arranging  a 
voltaic  pair  in  the  Philosophical  Transactions  for  1836.  Ilr/.  259  shows  one  cell  complete 
of  Daniell's  combination,  which  from  its  behavior  is  called  a  constant  battery,  a  is  a  cop- 
per vessel ;  b  a  rod  of  zinc,  contained  in  a  tube  c  of  porous  earthenware.  The  liquid  within 
the  tube  c  is  salt  and  water,  in  wliich  case  the  zinc  is  in  its  natural  state ;  or,  sul])huric  acid 
and  water,  in  which  ease  the  zinc  is  amalgamated  ;  the  latter  arrangement  being  the  more 
active  of  the  two.  The  liquid  in  the  outer  vessel  a  consists  of  cry.stals  of  sulphate  of  cop- 
per, dissolved  in  water.  At  c  is  a  perforated  shelf  of  copper  below  the  surface  of  the  liquid, 
upon  which  are  placed  spare  crystals  of  sulphate  of  copper,  which  dissolve  as  required,  and 
serve  to  keep  up  the  strength  of  the  solution  in  proportion  as  the  copper  already  there  is 
extracted  by  the  voltaic  action  hereafter  to  be  described,  a  and  b  are  screws,  to  which 
wires  may  be  attached,  in  order  to  connect  up  the  cell  and  convey  the  current  from  it  into 

any  desired  apparatus.  Certain  chemical 
changes  take  place  when  this  instrument  is  in 
action  ;  oxygen  from  the  water  within  the 
porous  tube  combines  with  zinc,  making  oxide 
of  zinc,  which  enters  into  combination  with 
sulphuric  acid,  producing  as  a  final  restilt  sul- 
phate of  zinc ;  hydrogen  is  liberated  from 
water  in  the  outer  cell,  and  itself  Jibeiatcs  oxy- 
gen from  oxide  of  copper,  and  comliines  with 
it,  producing  water,  and  leaving  copper  free. 
As  far  as  the  metals  are  concerned,  zinc  is 
consumed  from  the  rod  n,  at  the  one  end,  and 
copper  is  liberated  tipon  the  plate  a,  at  the 
other  end.  These  actions  are  slow  and  continu- 
ous ;  and  the  copper,  as  it  is  liberated  atom  by 
atom,  appears  upon  the  inner  surface  of  the 
cell ;  and  after  a  sufficient  quantity  has  been 
accumulated,  may  be  peeled  off  or  removed ; 
when  it  will  be  found  to  present  the  marks 
and  features  of  the  surface  from  which  it  has 
been  taken,  and  which,  as  we  have  already  said,  arrested  the  attention  of  many  into  whose 
hands  this  instrument  fell.  A  slight  modification  of  the  above  arrangement  gives  us  a  reg- 
ular electrotype  apparatus.     The  cell  c  in  this  arrangement  {J!(/.  260)  is  of  glass  or  poree- 


250 


260 


ELEOTEO-METALLURGY. 


491 


lain,  or  gutta  percha,  filled  as  before  with  a  saturated  solution  of  sulphate  of  copper,  to 
which  a  little  free  acid  is  generally  added ;  it  is  provided  with  a  shelf  or  other  means  of 
suspending  crystals  of  sulphate  of  copper.  A  zinc  rod  z  is  placed  in  a  porous  tube  p,  as 
already  described  ;  and  m,  the  other  metal  of  the  voltaic  pair,  is  suspended  in  the  copper 
solution  and  connected  with  the  zinc  z  by  the  wire  ik.  The  electric  current  now  passes ; 
zinc  is  consumed,  as  in  fi(j.  259,  but  copi)er  is  now  deposited  on  the  metal  m  front  and 
back,  and  on  as  much  of  the  wire  w  as  may  be  in  the  liquid  ;  or,  if  Mr.  Spencer's  precau- 
tion is  taken  of  varnishing  the  wire  and  the  back  of  the  metal  m,  all  the  copper  that  is  lib- 
erated will  be  accumulated  on  the  face  of  m.  If  salt  and  water  or  very  weak  acid  water  is 
contained  in  the  porous  tube  j>,  and  the  zinc  z  does  not  considerably  exceed  in  size  the 
metal  ?/;,  the  conditions  will  be  complied  with  for  depositing  copper  in  a  compact  reguline 
form. 

It  is  obvious  that,  with  this  arrangement,  m  may  be  a  mould  or  other  form  in  metal,  and 
that  a  copy  of  it  may  be  obtained  in  copper.  Fusible  metal,  consisting  of  8  parts  of  bis- 
muth, 4  of  tin,  5  of  lead,  and  1  of  antimony;  or  8  parts  bismuth,  3  tin,  and,  5  lead,  is 
much  used  for  taking  moulds  of  medals.  The  ingredients  are  well  melted  together  and 
mixed  ;  a  quantity  sufficient  for  the  object  in  view  is  poured  upon  a  slab  or  board  and  stirred 
together  till  about  to  set ;  the  film  of  dross  is  then  quickly  cleared  from  the  surface  witli  a 
card,  and  tlie  cold  metal  is  eitlier  projected  upon  the  bright  metal,  or  being  previously  fitted 
in  a  block  of  wood,  is  applied  with  a  sudden  blow.  Moulds  of  wax  or  stearine  variously 
combined,  or  more  recently  and  better  in  many  cases,  moulds  of  gutta  percha,  are  applicable 
to  many  purposes.  But,  as  none  of  these  latter  materials  conduct  electricity,  it  is  necessary 
to  provide  them  with  a  conducteous  surface.  Plumbago  or  black  lead  is  almost  universally 
employed  for  this  purpose  ;  it  is  rubbed  over  the  surface  of  the  mould  with  a  piece  of  wool 
on  a  soft  brush,  care  being  taken  to  continue  it  as  far  as  to  the  conducting  wire,  by  which 
the  mould  is  connected  with  the  zinc.  With  moulds  of  solid  metal,  the  deposit  of  copper 
commences  throughout  the  entire  surface  at  once  ;  but,  with  moulds  having  only  a  film  of 
plumbago  for  a  conductor,  the  action  commences  at  the  wire,  and  extends  itself  gradually 
until  it  has  been  developed  on  all  parts  of  the  surface. 

The  nature  of  the  electro-chemical  decompositions  that  are  due  to  the  passage  of  voltaic 
cun-ents  through  liquids,  especially  through  liquids  in  which  metal  is  in  certain  forms  con- 
tained, can  be  best  understood  by  studying  the  arrangement  that  is  most  commonly  used  in 
the  arts,  wherein  the  voltaic  apparatus,  from  which  the  electric  current  is  obtained,  is  dis- 
tinct and  separate  from  the  vessel  in  which  the  electro-metallurgical  operations  are  being 
brought  about.     Such  an  arrangement  is  shown  in  ji(j.  261,  where  a  is  a  DanieU's  cell,  as 

2G1 


in  fig.  259  ;  and  b  a  trough  filled  with  an  acid  soliitioa  of  sulphate  of  copper;  m  is  a  metal 
rod,  on  which  the  moulds  are  hung ;  and  c  a  metal  rod,  upon  wliicli  plates  of  copper  arc 
hung  facing  the  moulds ;  the  copper-plates  are  connected  by  the  wire  z  with  the  coiii)cr  of 
the  battery  cell,  and  tlie  moulds  by  the  wire  x  with  the  zinc  rod.  The  voltaic  current  is 
generated  in  the  cell  a,  and  its  direction  is  from  the  zinc  rod,  through  the  solutions  to  the 
copper  of  the  coll ;  thence  by  the  wire  ,?  to  the  plates  of  copper  c ;  through  the  sulphate 
solution  to  the  moulds  m  ;  and  thence  by  the  wire  x  to  the  zinc  rod.  In  this  arrangement, 
no  slielf  is  necessary  in  the  trough  n  for  crystals  of  sulphate  of  copper  to  keej)  up  the 
strength  of  the  solution  ;  for  the  nature  of  tiie  clectro-clicmical  decompositions  is  such, 
that  in  proportion  as  copper  is  al)stracted  and  deposited  upon  the  moulds  ??;,  other  copper 
is  dissolved  into  the  solution  from  the  plates  c.  Water  is  tiie  prime  subject  of  decomposi- 
tion. It  is  a  compound  body,  consisting  of  tiie  gases  oxygen  and  hydrogen,  and  may  be 
represented  by  fi(j.  202,  where  the  arrows  show  the  direction  in  which  the  current,  by  the 
wire  /),  enters  the  trough  b  oi  fi(j.  201  by  the  plate  of  copper  c,  and  passes  through  the 


492 


ELEOTEO-METALLURGY. 


/^ 


262 


0300(20 


water  in  the  direction  shown,  and  leaves  it  after  traversing  the  mould  by  the  wire  n.  Two 
atoms  of  water  o  h  and  o'  h',  as  bracketed  1  and  2,  are  shown  to  exist  before  the  electric 
current  passes  ;  and  two  atoms,  one  of  water  h  o',  (bracketed 
1',)  and  one  of  oxide  of  copper  o  c,  exist  after  the  action. 
On  the  one  hand,  an  atom  of  copper  c  has  come  into  the 
solution  ;  and,  on  the  other  hand,  the  atom  of  hydrogen  h', 
belonging  to  the  second  atom  of  water,  is  set  free  and  rises 
in  the  form  of  gas.  The  explanation  is  to  show  that  oxygen 
is  liberated  where  the  current  enters,  and  combines  there  in 
•"^  .^x^  ^  its  nascent  state  with  cop/icr.-  it  would  not  have  combined, 

for  instance,  with  gold  or  platinum.  We  might  easily  extend 
this  symbolical  figure,  and  show  how  that,  when  free  sulphuric  acid  is  in  the  solution,  the 
oxide  of  copper  on  its  formation  combines  with  this  acid  to  produce  the  sulphate  of  copper 
required  ;  and  how,  when  free  sulphate  of  copper  is  present,  the  hydrogen,  instead  of  being 
freed  in  the  form  of  gas,  combines  with  oxygen  of  the  oxide  of  copper,  and  liberates  the 
metal  which  in  its  nascent  state  is  deposited  on  the  mould,  and  produces  the  electrotype 
copy  of  the  same.  One  battery  cell  is  sufficient  for  working  in  this  way  in  copper ;  it  is 
increased  in  size  in  proportion  to  the  size  of  the  object  operated  upon.  And,  although  for 
small  objects,  such  as  medals,  a  vertical  arrangement  will  act  very  well ;  for  large  objects  it 
has  been  often  found  of  great  advantage  to  adopt  a  horizontal  arrangement,  placing  the  mould 
beneath  the  copper-plate.  The  varying  density  of  a  still  solution  in  the  vertical  arrange- 
ment is  not  witho>it  its  effect  upon  the  nature  of  the  deposit,  both  on  its  character  and  its 
relative  thickness.  This  has  been  in  some  instances  obviated,  and  the  advantage  of  the 
vertical  method  retained  by  keeping  the  solution  in  motion,  either  by  stirring  or  by  a  con- 
tinuous flow  of  liquid. 

We  have  described  principally  Daniell's  battery  as  the  generating  cell  in  electro-metal- 
lurgical operations ;  but  Mr.  Smee's  more  simple  arrangement  of  platinized  silver  and  zinc, 
excited  with  diluted  sulphuric  acid,  has  been  found  in  practice  more  economical  and  con- 
venient. 

Fig.  263  is  a  Smee's  cell ;  a  vessel  of  wood,  glass,  or  earthenware  contains  diluted  sul- 
phuric acid,  one  in  eight  or  ten,  a  platinized  silver  plate  s,  sustained  by  a  piece  of  wood  w, 
with  a  plate  of  zinc  z  z  on  each  side,  so  as  to  turn  to  useful  account  both 
sides  of  the  silver  plate.  The  zinc  plates  are  connected  by  the  binding 
screw  6.  Platinization  consists  in  applying  platinum  in  fine  powder  to 
the  metallic  surface.  When  hydrogen  is  liberated  by  ordinary  electric 
action  upon  a  surface  so  prepared,  it  has  no  tendency  to  adhere  or  cling 
to  it  \  but  it  at  once  rises,  and  in  fact  gets  out  of  the  way,  so  that  it 
never,  by  its  presence  or  lingering,  interferes  with  the  prompt  and  ready 
continuance  of  the  electric  action  ;  and  in  this  way  the  amount  of  supj)ly 
is  well  kept  up. 

Platinization  is  itself  another  illustration  of  working  in  metal  by 
electricity.  A  few  crystals  of  chloride  of  platinum  are  dissolved  in  diluted 
sulphuric  acid.  A  voltaic  current  is  made  to  enter  this  solution  by  a  plate 
of  platinum,  and  to  come  out  by  a  silver  plate.  Two  or  three  DanielFs 
or  Smee's  cells  arc  necessary  for  the  operation.  The  chloride  of  platinum 
is  decomposed,  and  the  metal  is  deposited  upon  the  silver  plate ;  not, 
however,  in  the  reguline  compact  form,  as  in  the  case  of  copper,  but  in  a 
state  of  black  powder  in  no  way  coherent.  This  affords  also  an  illustra- 
tion of  the  different  behavior  of  metals  under  analogous  circumstances.  Copper  is  of  all 
metals  the  most  manageable  ;  platinum  is  among  the  more  unmanageable. 

Mr.  C.  V.  Walker  has,  with  great  advantage,  substituted  graphite  for  silver.  The 
material  is  obtained  from  gas  retorts,  and  is  cut  into  plates  a  quarter  of  an  inch  thick,  or 
thicker,  when  plates  of  a  large  size  are  cut.  He  platinizes  these  plates  in  the  usual  way  as 
above  described,  and  deposits  copper  on  their  upper  parts,  also  by  electrotype  process,  and 
solders  a  copper  slip  to  the  electrotype  copper,  in  order  to  make  the  necessary  connection. 
With  the  exception  of  silver  and  gold,  copper  is  the  metal  which  has  been  most  exten- 
sively worked  by  these  processes. 

Skals  are  copied  by  obtaining  impressions  in  sealing-wax,  pressing  a  warm  wire  into  the 
edge  for  a  connection ;  rubbing  black-lead  over  the  wax  to  make  the  surface  conducteous  ; 
fastening  a  slip  of  zinc  to  the  other  end  of  the  wire  ;  wrapping  the  zinc  in  brown  paper, 
and  putting  the  whole  into  a  tumbler  containing  sulphate  of  copper,  a  little  salt-water  hav- 
ing been  poured  into  the  lirown  paper  cell. 

ri,.\sTF,R  OF  Paris  Medallions  may  be  saturated  with  wax  or  stearine,  and  then  treated, 
if  small,  like  seals ;  if  large,  in  a  distinct  trough,  as  in  firj.  261.  In  this  case  the  copy  is 
in  intaglio,  and  may  be  used  as  a  mould  for  obtaining  the  fac-simile  of  the  cast.  More 
commonly,  the  cast  is  saturated  with  warm  water,  and  a  mould  of  it  taken  in  wax,  stearine, 
or  gutta  pcrcha.     This  is  treated  with  black-lead,  and  in  other  respects  the  same  as  seals. 


ELECTEO-METALLURGY. 


493 


Wood-cuts  are  treated  with  black-lead,  and  a  copper  reverse  13  deposited  upon  them. 
This  is  used  as  a  mould  to  obtain  electrotype  duplicates,  or  as  a  die  for  striking  ofiF  dupli- 
cates. 

Stkreotypk  Plates  are  obtained  in  copper  by  taking  a  plaster  copy  of  the  type,  treat- 
ing it  plaster  fashion,  depositing  a  thin  plate  of  copper  upon  it,  and  giving  strength  by 
backing  up  with  melted  lead. 

Old  Brasses  may  be  copied  by  the  intervention  of  plaster. 

Embossed  cards  or  paper  may  be  copied  by  first  saturating  with  wax  and  then  using 
black-lead. 

FiitJiT  may  be  copied  by  the  intervention  of  moulds,  or  may  be  covered  with  copper. 
Leaves,  twigs,  and  branches  may  have  copper  deposited  upon  them.     The  same  for 

STATU KTTES,  BUSTS,  and  STATUES. 

Leaves  and  flowers  are  furnished  with  a  conducting  surface  by  dipping  them  into  a  solu- 
tion of  phosphorus  in  bisulphuret  of  carbon,  and  then  into  a  solution  of  nitrate  of  silver. 
Silver  is  thus  released  in  a  metallic  state  upon  their  surface. 

Plaster  busts,  &c.,  have  been  copied  in  copper,  by  first  depositing  copper  on  the  plas- 
ter prepared  for  this  operation  ;  when  thick  enough,  the  original  bust  is  destroyed,  the  cop- 
per shell  is  filled  with  sulphate  of  copper,  as  in  Jig.  201,  and  copper  is  deposited  on  its 
inner  surface  till  of  sufficient  thickness ;  the  outer  shell  is  then  removed. 

Tubes  and  vessels  of  capacity  do  not  appear  to  have  been  profitably  multiplied  by  elec- 
trotype. 

Plates  have  been  prepared  for  the  engraver  to  work  on  by  depositing  copper  on  pol- 
ished copper-plates,  and  removing  the  deposits  when  thick  enough. 

For  the  multiplication  of  engraved  copper-plates,  the  electrotype  process  has  been 
very  extensively  adopted.  A  reverse  of  the  plate  is  first  obtained  by  the  deposition  of  cop- 
per ;  this  serves  as  a  mould,  from  which  many  copies  of  the  original  plate  are  obtained  by 
depositing  copper  upon  it,  and  then  separating  the  two.  The  mode  practised  by  the  Duke 
of  Leuchtenberg  is  to  print  from  an  engraved  plate  on  very  thin  paper  with  a  mixture  of 
resin  of  Damara,  red  oxide  of  iron,  and  essence  of  turpentine.  Wliile  the  impression  is 
wet,  the  paper  face  downwards  is  pressed  upon  a  polished  plate  of  copper.  When  dry  the 
paper  is  washed  away,  and  the  impression  remains.  An  electrotype  copy  from  this  is  ob- 
tained in  intaglio,  and  is  fit  for  the  use  of  the  printer. 

Galvanography  is  a  picture  drawn  originally  in  varnish  on  the  smooth  plate,  and  then 
treated  in  a  similar  way  to  the  above. 

The  plates  on  rollers  used  by  calico  printers  have  been  multiplied  like  engraved 
plates. 

Glyphography  is  a  name  given  by  Mr.  Palmer  to  his  process.  He  blackens  a  fair  cop- 
per-plate with  sulphuret  of  pota.ssium,  covering  it  uniformly  with  a  coating  of  wax  and 
other  things,  then  draws  the  design  through  the  wax  with  fine  tools.  From  the  plate  thus 
prepared,  an  electrotype  is  taken  in  the  usual  way,  and  is  backed  up  and  mounted  as  an 
electro-glyphic  cast  to  print  from  as  from  a  wood  block.  For  a  siereo-t/li/phic  cast  to  work 
from  as  a  stereotype  plate,  a  plaster  copy  is  taken  of  the  original  drawing,  the  high  lights 
are  cut  out,  and  then  an  electrotype  copy  is  made. 

Electro-tint  is  done  by  drawing  with  wax  or  varnish  any  design  on  a  fair  copper-plate, 
and  making  an  electrotype  copy  for  the  printer's  use. 

Fern-leaves,  &c.,  are  copied  by  being  laid  on  a  sheet  of  soft  gutta  percha,  pressed  into 
the  surface  by  a  smooth  plate  to  which  pressure  is  applied,  and  then  removed  in  order  to 
subject  the  gutta  percha  mould  to  the  electrotype  process.  This  is  Nature  Printing, 
which  see. 

MM.  Auer  and  Worring  have  copied  lace,  embroidery,  flowers,  leaves  of  trees,  entire 
plants,  fossils,  insects,  &c.,  in  their  natural  relief,  by  laying  the  objects  upon  a  plate  of  cop- 
per, after  having  soaked  them  in  spirits  of  wine  and  turpentine  so  as  to  fix  them.  A  plate 
of  clean  lead  is  laid  over,  and,  on  being  pressed,  an  intaglio  copy  is  produced  on  it  of  the 
object.     From  this  an  electrotype  is  obtained. 

Undercut  medallions,  &c.,  are  copied  in  elastic  moulds  made  of  treacle  and  glue  in 
the  proportions  of  1  to  4.     Masks  and  busts  may  also  be  obtained  in  such  moulds. 

Electro-clotii  was  made  by  saturating  the  fibre  of  canvas  or  felt,  making  it  conducte- 
ous  in  tl\e  usual  way ;  it  was  proposed  in  place  of  tarpaulins  as  a  water-tight  cover. 

Retorts  and  cituciiiLKS,  &c.,  of  glass  or  porcelain,  have  been  successfully  coated  with 
electrotype  copper  l)y  first  varnishing  or  otherwise  preparing  the  surface  to  retain  the  black- 
lead,  and  then  treating  them  as  usual. 

Soldering  copper  surfaces  has  been  accomplished  by  galvanic  agency.  The  ends  to  be 
united  are  placed  togetlier  in  the  sohition  of  sulpliate  of  copi)cr,  and  cionncctcd  with  the 
battery  as  for  ordinary  deposition.  Parts  not  included  in  tlie  process  are  protected  ofl'  by 
varnish  ;  copper  is  then  deposited  so  as  to  unite  the  separate  pieces  into  one. 

Iron  may  be  coated  with  copper.  But  here  a  new  feature  comes  into  view.  Sul- 
phuric acid  leaves  the  copper  of  the  sulphate,  combines  with  iron,  and  deposits  copper  on 


494  ELECTRO-METALLURGY. 

its  surface  without  the  aid  of  the  voltaic  apparatus.  The  iron  surface  is  imperfectly  cov- 
ered with  copper  ;  no  firm  perfect  deposit  occurs.  In  order  to  obtain  solid  deposits  of  cop- 
per on  iron,  it  is  necessary  to  use  a  solution  that  has  no  ordinary  chemical  reaction  upon 
iron.  Cyanide  of  copper  is  used,  which  may  be  obtained  by  dissolving  sulphate  of  copper 
in  cyanide  of  potassium.  This  solution  requires  to  be  raised  to  and  retained  at  a  tempera- 
ture not  greatly  below  200°,  in  order  to  give  good  results. 

Electro-zixcixg  is  applied  to  surfaces  of  iron,  in  order  to  protect  them  from  corrosion. 
A  solution  is  made  of  suljjhate  of  zinc,  which  is  placed  in  a  trough  b.  Jig.  261.  Two  or 
three  battery  cells  are  required.  The  iron  to  be  zinced  is  connected  with  the  zinc  end  of 
the  battery,  and  a  plate  of  zinc  with  the  copper  end. 

Voltaic  brass  does  not  appear  to  have  been  obtained  in  a  solid  distinct  form,  but  has 
been  successfully  produced  as  a  coating  upon  a  copper  surface.  Separate  solutions  are 
made  of  sulphate  of  copper  and  of  sulphate  of  zinc  in  cyanide  of  potassium.  The  two 
solutions  are  then  mixed,  and  placed  in  a  decomposing  trough.  Two  or  three  cells  of  a 
battery  are  used,  and  a  brass  plate  connected  with  the  copper  end.  An  electrotype  copper 
medal  or  other  prepared  stn-face  is  connected  with  the  zinc.  Urilliant  and  perfect  brass 
soon  appears,  and  will  deposit  slowly  for  some  hours  ;  but  after  a  while  the  character  of  the 
solution  changes,  and  copper  appears  in  place  of  brass. 

This  hasty  glance  at  the  leading  applications  of  this  art  will  give  an  idea  of  its  utility. 
It  also  comes  into  play  in  cases  where  least  suspected.  Pins  were  tinned  by  electrotype  long 
before  the  art  was  known.  Brass  pins  are  thrown  into  solution  of  tin  in  cream  of  tartar, 
and  are  unchanged  ;  but  when  a  lump  of  tin  is  throwni  among  them,  a  voltaic  pair  is  formed, 
and  tin  is  deposited  on  all  the  heap.  Any  stray  pins  detached  from  the  mass,  escape  the 
influence.  y{)ace  would  fail  us  were  we  to  go  through  the  list  of  crystalline  and  of  simple 
bodies  formed  by  these  processes ;  as  for  instance,  octahedral  crystals  of  protoxide  of  cop- 
per; tetnihedrai  crystals  of  proto-chloride  of  copper;  octahedral  crystals  of  sulphide  of 
silver ;  crystals  of  subnitrate  of  co|)per ;  bibasic  carbonate  of  copper,  and  others  too  nu- 
merous to  name,  have  all  been  formed  by  slow  voltaic  actions.  The  alkaline  metals,  potas- 
siuni,  sodium,  etc.,  were  first  obtained  by  Davy  in  the  galvanic  way  ;  magnesium,  barium, 
aluminium,  calcium,  &c.,  are  obtained  by  M.  Bunscn  by  operating  upon  the  chlorides  of 
these  metals  either  in  solution  or  in  a  state  of  fusion. 

Electro-etcming  is  produced  at  the  place  where  the  current  entcra  the  decomposing 
trough,  as  at  the  copper-plates  c  of  Ji p.  261.  A  plate  of  copper  is  prepared  as  if  ibr  the 
graver ;  its  face  is  then  covered  with  an  etching  ground  of  asphalte,  wax,  black  pitch,  and 
Burgundy  pitch  ;  and  its  back  with  varnish.  The  design  is  then  traced  through  the  etching 
ground  with  a  fine  point ;  the  plate  is  then  placed  in  tlic  trough  B,  containing  cither  sul- 
phate of  copper  or  simply  diluted  sulphuric  acid,  and  connected  with  the  copper  of  the 
battery.  After  a  few  minutes  it  is  removed,  and  the  fine  lines  are  stcipjicd  out  with  var- 
nish ;  it  is  then  replaced,  and  again,  after  a  few  minutes,  is  removed,  and  the  darker  shades 
are  stopped  out;  the  parts  still  exposed  are  again  subjected  to  the  action,  and  the  etching 
is  complete.  When  the  ground  is  removed,  the  design  will  be  found  etched  upon  the  cop- 
per-plate, ready  for  the  printer. 

Dagcerreottpe  ETi  hing  is  a  delicate  operation,  and  requires  much  care.  The  solution 
employed  by  Professor  Grove  was  Jiydrochloric  acid  and  water  in  equal  parts,  and  a  battery 
of  two  or  three  cells. 

Platinized  silver  is  used  in  face  of  the  daguerreotype,  instead  of  copper.  The  result 
comes  out  in  about  half  a  minute.  An  oxychloride  of  silver  is  formed,  and  the  mercury 
of  the  plate  remains  untouched. 

A  PnoTO-GALVA.NO-GRAPiiic  Company  has  been  formed  in  London  for  carrying  out  the 
process  of  Paul  Pretsch.  He  makes  solutions  of  bichromate  of  potash  in  glue  water,  or  in 
solution  of  gelatine,  instead  of  in  pure  water.  lie  then  treats  the  glass  or  plate  with  these, 
and  in  the  usual  way  takes  a  picture.  lie  washes  the  gelatine  picture  with  water,  or  solu- 
tion of  l)orax  or  carbonate  of  soda,  which  leaves  the  picture  in  relief;  when  developed,  he 
washes  with  spirits  of  wine,  and  obtains  a  sunk  design.  The  surfaces  thus  prepared,  or 
moulds  made  from  them  in  one  or  other  of  the  modes  already  described,  are  placed  in  a 
galvano-plastic  apparatus  for  ol)taining  an  "engraved  plate  from  which  to  print.     See  Puoto- 

OUAl'IIIC  ENGr.AVlNG. 

The  Duke  of  Leuchtenberg  prepares  a  plate  for  etching  by  leaving  the  design  on  the 
ground,  and  removing  the  ground  for  the  blank  parts.  When  his  electrotvpc  operation  is 
complete,  the  design  is  in  relief  instead  of  being  in  intaglio,  as  in  ordinary  etching. 

Mr.TAr.i.o-cnROMES  consist  of  thin  films  of  oxide  of  lead,  deposited  sometimes  on  pol- 
ished plates  of  platinum,  but  most  commonly  on  polished  steel  plates.  The  colors  are  most 
brilliant  and  varied.     Nobili  is  the  author  of  the  process. 

A  saturated  solution  of  acetate  of  lead  is  prepared  and  placed  in  a  horizontal  trough. 
Three  or  four  battery  cells  arc  required.  A  steel  plate  is  laiil  in  the  acetate  of  lead  with  its 
polished  surface  upward,  and  is  connected  with  the  copper  of  the  battery.  If  a  wire  is  con- 
nected with  the  zinc  end  of  the  battery,  and  held  over  the  steel  plate  in  the  solution,  a 


ELECTRO-METALLURGY. 


495 


series  of  circles  in  brilliant  colors  arises  from  the  spot  immediately  beneath  the  wire,  and 
expands  and  spreads,  like  the  circles  when  a  stone  is  thrown  into  a  pond.  Silver-blond  is  the 
first  color ;  then  fawn-color,  followed  by  the  various  shades  of  violet,  and  indigoes  and 
bhies ;  lake,  bluish  lake,  green  and  orange,  greenish  violet,  and  passing  through  reddish 
yellow  to  rose-lake,  which  is  the  last  color  in  the  series. 

According  to  the  shape  of  the  metal  by  which  the  current  enters — be  it  a  point,  a  slip, 
a  cross,  a  concave,  or  a  convex  disc — so  is  the  form  of  the  colored  figure  varied.  And  if, 
in  addition  to  this,  a  pattern  in  card  or  gutta  percha  is  cut  out  and  interi)osed  between  the 
two  surfaces,  the  action  is  intercepted  by  the  portions  not  removed,  and  the  design  is  pro- 
duced on  the  steel  plate,  in  colors,  that  may  be  greatly  varied,  according  to  the  duration  of 
the  experiment.  The  different  colors  are  due  to  the  different  thicknesses  of  the  thin  lilnis 
of  peroxide  of  lead. 

M.  Becquerel  proposed  the  deposit  of  peroxide  of  lead,  and  also  the  red  peroxide  of 
iron,  for  protecting  metals  from  the  action  of  the  atmosphere.  For  the  latter,  prutosulpluite 
of  iron  is  dissolved  in  ammonia  solution,  and  operated  upon  by  two  or  three  batteries. 

The  most  important  application  of  electro-metallurgy  in  the  arts  has  been  for  plating 
and  GILDING,  which  is  most  extensively  carried  on  both  at  home  and  abroad.  Results  that 
were  unattainable,  and  others  attainable  only  at  great  cost,  are  readily  produced  by  this 
mode  of  manipulating.  The  liquids  most  in  use  are  the  cyanide  solutions,  first  introduced 
by  Messrs.  Elkingtons.  They  are  prepared  in  various  ways.  Cyanide  of  j)otassium  is  added 
carefully  to  dilute  solution  of  nitrate  of  silver ;  and  the  white  deposit  of  cyanide  of  silver 
is  washed,  and  then  dissolved  in  other  cyanide  of  potassium  ;  or  lime  water  is  added  to  the 
nitrate  solution,  and  the  brown  deposit  of  oxide  of  silver  is  washed,  and,  while  moist,  is 
dissolved  in  cyanide  of  potassium ;  or  common  salt  is  added  to  the  nitrate  solution,  and  the 
white  deposit  of  chloride  of  silver  is  washed  and  dissolved  in  cyanide  of  potassium.  Or  a 
solution  of  cyanide  of  potassium  is  placed  in  the  trough  b,  fig.  261  ;  and  the  current  from 
three  or  four  cells  is  passed  into  it  from  a  silver  plate  at  e,  which  combines  with  and  is  dis- 
solved into  the  liquid,  converting  it  into  a  cyanide  of  silver  solution.  To  prevent  silver 
being  abstracted  by  deposition  at  ?»,  as  the  current  leaves  the  trough,  the  metal  at  »/i  is 
placed  within  a  porous  cell  of  cyanide  solution,  so  as  to  limit  the  action. 

Gold  solution  is  obtained  by  dissolving  the  anhydrous  peroxide  of  gold  in  cyanide  of 
potassium,  or  by  treating  chloride  of  gold  with  cyanide  of  potassium,  or  by  using  a  gold 
plate  and  a  voltaic  current  with  a  solution  of  cyanide  of  potassium  in  the  same  way  as  de- 
scribed for  silver ;  and  allowing  the  action  to  continue  until  the  solution  is  sufficiently 
strong  of  gold.  With  these  solutions  electro-plating  and  gilding  are  readily  accomplished. 
There  are  other  solutions  more  or  less  valuable,  which  wilf  be  found  in  the  books  that  treat 
upon  the  subject. 

Fig.  266  is  an  arrangement  for  operations  on  a  small  scale.     The  vessel  a  b,  containing 

266 


the  gold  solution,  rests  over  a  small  stove  or  spirit-lamp.  The  objects  to  be  gilt  are  sus- 
pended by  wires  to  the  conducting  rod  d,  in  connection  with  the  zinc  end  of  the  battery ; 
and  the  gold  wire  or  plate  c  is  connected  with  the  other  end.  A  temperature  of  from  100" 
to  200'  is  desirable  ;  the  higher  temperatures  require  fewer  battery  cells ;  with  the  highest, 
one  will  suffice.  The  solution  of  course  evaporates  under  the  influence  of  heat ;  and  dis- 
tilled water  must  be  added  to  supply  the  loss,  before  each  fresh  operation. 

Plating  and  gilding  is  successfully,  and,  in  point  of  economy,  advantageously  carried  on 
at  Birmingham,  in  more  than  one  manufactory,  by  means  of  magnetoeiectricity.  In  the 
article  on  Electkic-Ticlegkapiiv,  will  be  found  a  description  of  this  form  of  electric  force, 
and  the  means  by  which  it  is  produced.  An  electro-magnet  is  set  in  motion  in  front  of  the 
poles  of  a  perinanent  magnet,  in  such  a  manner  that  the  soft  iron  core  of  the  electro-mag- 
net becomes  alternately  a  magnet  and  not  a  magnet;  in  the  act  of  becoming  a  magnet,  it 
raises  up  a  current  in  one  direction  in  the  wire  wjth  which  it  is  wound  ;  in  the  act  of  ceas- 
ing to  be  a  magnet,  it  raises  up  a  current  in  the  reverse  direction.     The  ends  of  the  wire 


496 


ELECTRO-MOTIVE  ENGINES. 


are  led  away  and  insulated.  The  instrument  is  fitted  with  a  commutator,  so  adjusted  that 
it  collects  the  currents  from  the  ends  of  the  wire,  and  guides  them  in  a  uniform  direction 
into  the  vessel  that  contains  the  solution  and  articles  to  be  gilded  or  plated.  In  practice  a 
single  machine  consists  of  many  electro-magnets  grouped  together,  and  many  powerful  ma<'- 
nets  for  exciting  them  ;  by  which  means  a  continuous  flow  of  a  large  amount  of  electriciry 
is  obtained.     Fig.  267  is  an  illustration  of  such  an  arrangement  as  adapted  by  Mr.  Wool- 


rich  :  a  a  a  a  are  four  clusters  of  permanent  steel  magnets,  seen  from  above  ;  b  b  b  b  b  \s 
the  frame-work  of  the  machine  ;  c  c  c  c  are  four  bars  of  soft  iron,  wound  with  large  size 
insulated  copper  wire  ;  J  is  a  circular  disc,  on  which  they  are  mounted  and  which  rotates 
on  a  vertical  axis,  of  which  /  shows  the  upper  end  ;  e  is  the  commutator,  from  which  two 
wires  are  led  off  to  the  solution  to  be  operated  upon.  The  permanent  magnets  are  U- 
shaped ;  one  pole  only  of  each  bundle  is  visible ;  the  other  is  beneath  the  disc  d,  and  its 
freight  of  electro-magnets  c  c,  &c.  The  axis  is  set  in  rotation  by  a  strap  passing  over  the 
drum  of  a  shaft  of  the  steam-engine,  that  does  the  ordinary  work  in  a  factory ;  and  the 
disc  carries  the  electro-magnets  between  the  poles  of  the  permanent  magnets,  and  exposes 
them  to  the  most  favorable  action  of  these  poles.  The  number  of  coils  and  magnets  vary 
in  proportion  to  the  work  required.  By  this  arrangement  not  only  does  each  coil  pass 
under  the  influence  of  many  magnets,  but  each  magnet  acts  successively  on  many  coils ; 
and  a  proportionate  supply  of  electricity  is  the  result. — C.  V.  W. 

ELECTRO-MOTIVE  ENGINES.  Electro-magnetism  undoubtedly  affords  an  almost 
unlimited  power.  An  electro-magnet  may  be  constructed  which  shall  have  a  lifting  power 
equal  to  many  tons.  It  is  probable  that  there  are  limits  beyond  which  it  would  not  be  pos- 
sible to  increase  the  power  of  electro-magnets ;  those  limits  have  not  yet  been  reached ; 
but  supposing  them  to  be  attained,  there  is  nothing  to  prevent  the  multiplying  of  the  num- 
ber of  electro-magnets  in  the  arrangements.  It  may  be  stated,  in  connection  with  this  part 
of  the  subject,  that  from  experiments  made  with  Hearder's  magnetometer,  it  appears  that 
the  development  of  magnetism  in  iron  observes,some  special  peculiarities.  These  may  be 
thus  stated  : — With  the  same  electro-magnet  there  is,  as  the  voltaic  pairs  in  the  battery  are 
increa.sed,  a  gradual  increase  of  magnetic  force.  With  from  one  to  seven  elements  there 
appears  an  average  excess  of  .31  lbs. ;  after  this  point,  with  the  increase  of  battery  power, 
by  the  addition  of  pair  after  pair  of  zinc  and  platinum  elements,  the  production  of  power 
bears  a  decreasing  ratio  to  the  power  employed,  and  at  last,  the  addition  of  five  elements 
was  not  found  to  produce  an  increase  of  effect  equivalent  to  the  value  of  one  element.  In 
all  experiments,  therefore,  on  electro-magnetic  machines,  the  experimentalist  has  first  to 
determine  the  utmost  power  which  the  soft  iron  is  capable  of  assuming,  in  relation  to, — 


ELECTRO-MOTIVE  ENGINES.  497 

1st.  The  number  of  coils  of  wire  on  the  iron  ;  and  2d.  The  number  of  elements  employed 
in  the  exciting  source — the  voltaic  battery.  The  length  of  the  iron  and  its  thickness  are 
also  points  demanding  special  considerations  from  the  constructor  of  an  electro-magnetic 
macliine. 

There  remains  now  to  examine  the  production  of  the  power,  Electro-Magnetism. 

The  electro-mechanician  is  dependent  upon  his  battery,  in  the  same  way  as  a  steam  en- 
gineer is  dependent  upon  his  fire  and  his  boiler,  for  the  production  of  mechanical  effect. 

Voltaic  batteries  vary  in  their  effects,  and  hence  arise  statements  which  differ  widely 
from  each  other,  as  to  the  result  obtained,  by  the  destruction  (?  change  of  form)  of  a  given 
quantity  of  metal  in  the  battery. 

Dr.Botto  states,  that  45  lbs.  of  zinc,  consumed  in  a  Grove's  battery,  are  sufficient  to 
work  one-horse  power  electro-magnetic  engine  for  twenty-four  hours. 

Mr.  Joule  says  the  same  results  would  have  been  obtained,  had  a  Daniell's  battery  been 
used,  by  the  consumption  of  75  lbs.  of  zinc. 

It  is  impossible,  oh  the  present  occasion,  to  enter  into  the  theory  of  the  voltaic  battery, 
or  to  describe  the  varieties  of  arrangement  which  have  been  adopted  for  generating  (de- 
veloping) electrical  force  in  the  form  of  a  current,  with  the  greatest  effect,  at  the  smallest 
cost. 

On  this  point  the  evidence  of  Jacobi  may  be  quoted  : — "  With  regard  to  the  magnetic 
machine,  it  will  be  of  great  importance  to  weaken  the  effects  of  the  counter  current,  with- 
out at  the  same  time  weakening  the  magnetism  of  the  bars.  It  is  the  alternate  combination 
of  the  pairs  of  plates  in  the  voltaic  pile,  which  permits  us  to  increase  the  speed  of  rotation 
at  will.  We  know  the  magnetic  power  of  the  current  is  not  sensibly  augmented  by  increas- 
ing the  number  of  the  pairs  of  plates,  but  the  counter  current  is  considerably  weakened  by 
its  being  forced  to  pass  through  a  great  many  layers  of  liquid.  In  fact,  on  using  twelve 
voltaic  pairs,  each  half  a  square  foot,  instead  of  four  copper  troughs,  each  with  a  surface 
two  square  feet,  which  I  had  hitherto  used,  the  speed  of  rotation  rose  at  least  250  or  300 
revolutions  in  a  minute." 

Mechanical  force,  whether  obtained  in  the  form  of  man-power,  horse-power,  steam-power, 
or  electrical-power,  is  the  result  of  a  change  of  form  in  matter.     In  the  animal,  it  is  the 
result  of  muscular  and  nervous  energy,  which  is  maintained  by  the  due  supply  of  food  to 
the  stomach.     In  the  steam-engine,  it  is  the  result  of  vapor  pressure,  which  is  kept  up  by 
the  constant  addition  of  fuel  to  the  fires  under  the  boilers.     In  the  magnetic  machine,  it  is 
the  result  of  currents  circulating  through  wires,  and  these  currents  are  directly  dependent 
upon  the  chemical  change  of  zinc  or  of  some  other  metal  in  the  battery.     Then, 
Animal  power  depends  on  food. 
Steam  power  depends  on  coal. 
Electrical  power  depends  on  zinc. 

An  equivalent  of  coal  is  consumed  in  the  furnace — that  is,  it  unites  its  carbon  with 
oxygen  to  form  carbonic  acid,  and  its  hydrogen  with  oxygen  to  form  water,  and  during  this 
cliange  of  state  the  quantity  of  heat  developed  has  a  constant  relation  to  the  chemical 
action  going  on. 

Mr.  Joule  has  proved  by  a  scries  of  most  satisfactory  experiments,  that  "  the  quantity 
of  heat  capable  of  increasing  the  temperature  of  a  pound  of  water  by  one  degree  of  Fahren- 
heit's scale  is  equal  to,  and  may  be  converted  into,  a  mechanical  force  capable  of  raising  838 
lbs.  to  the  perpendicular  height  of  one  foot." 

Mr.  J.  Scott  Russell  has  shown  that  in  the  Cornish  boilers,  at  Hue!  Towan  and  the  United 
Mines,  the  combustion  of  one  pound  of  Welsh  coal  evaporates  of  water,  from  its  initial 
temperature,  lO'SS"  and  10-48"  respectively.  "But,"  says  Mr.  Joule,  "we  have  shown 
that  one  degree  is  equal  to  838  lbs.  raised  to  the  height  of  one  foot.  Therefore  the  heat 
evolved  by  the  combustion  of  one  pound  of  coal  is  equivalent  to  the  mechanical  force 
capable  of  raising  9,584,206  lbs.  to  the  height  of  one  foot,  or  to  about  ten  times  the  duty 
of  the  best  Cornish  engines." 

Such  are  the  conditions  under  which  heat  is  employed  as  a  motive  power.  An  equiva- 
lent of  zinc  is  acted  on  by  the  acid  in  the  cells  of  the  battery,  and  is  oxidized  thereby.  In 
this  process  of  oxidation  a  given  quantity  of  electricity  is  sefin  motion  ;  but  the  quantity 
available  for  use,  falls  very  far  below  the  whole  amount  developod  by  the  oxidation  of  the 
zinc.  The  electricity,  or  electrical  disturbance,  is  generated  on  the  surface  of  the  zinc  ;  it 
passes  through  the  acidulated  fluid  to  the  copper  plate  or  platinum  plate,  and  in  thus  pass- 
ing from  one  medium  to  another,  it  has  to  overcome  certain  mechanical  resistances,  and 
thus  a  portion  of  the  force  is  lost.  This  takes  place  in  every  cell  of  the  voltaic  arrange- 
ment, and  consequently  the  proportion  of  zinc  which  is  consumed,  to  produce  any  final 
mechanical  result,  is  considerably  greater  than  it  should  be  theoretically. 

Joule  gives  as  the  results  of  his  experiments,  the  mechanical  force  of  the  current  pro- 
duced in  a  Daniell's  battery  as  equal  to  1,106,160  lbs.  raised  one  foot  high,  per  pound  of 
zinc,  and  that  produced  in  a  Grove's  battery  as  equal  to  1,843,600  lbs.  raised  one  foot  high, 
per  pound  of  zinc. 

Vol.  III.— 32 


498  ELECTRO-PLATING  AND  GILDING. 

It  need  scarcely  be  stated,  that  this  is  infinitely  above  what  can  be  practically  obtained. 
A  great  number  of  experiments,  made  by  the  Author  some  years  since,  enabled  him  to  de- 
termine, as  the  mean  average  result  of  the  currents  produced  by  several  forms  of  battery 
power,  that  one  grain  of  zinc,  consumed  in  the  battery,  would  exert  a  force  equal  to  lifting 
86  lbs.  one  foot  high.  Mr.  Joule  and  Dr.  Scoresby  thus  sum  up  a  series  of  experimental 
results  :  "  Upon  the  whole,  we  feel  ourselves  justified  in  fixing  the  maximum  available  duty 
of  an  electro-magnetic  engine,  worked  by  a  Daniell's  battery,  at  80  lbs.  raised  a  foot  high, 
for  each  grain  of  zinc  consumed."  This  is  about  one-half  the  theoretical  maximum  duty. 
In  the  Cornish  engines,  doing  the  best  duty,  one  grain  of  coal  raised  143  lbs.  one  foot  high. 
The  difference  in  the  cost  of  zinc  and  coal  need  scarcely  be  remarked  on.  The  present 
price  of  the  metal  is  £35  per  ton,  and  coal  can  be  obtained,  including  carriage  to  the  en- 
gines, at  less  than  £1  per  ton ;  and  the  carbon  clement  does  two-thirds  more  work  than  can 
possibly  be  obtained  from  the  metallic  one. 

By  improving  the  battery  arrangements,  operators  may  eventually  succeed  in  getting  a 
greater  available  electrical  force.  But  it  must  not  be  forgotten,  that  the  development  of 
any  physical  force  observes  a  constant  law.  Whether  in  burning  coal  in  the  furnace,  or 
zinc  or  iron  in  the  battery,  the  chemical  equivalent  reprusents  the  theoretical  mechanical 
power.  Therefore  the  atomic  weight  of  the  carbon  atom  being  G,  and  that  of  the  zinc  atom 
being  32,  it  is  not  practicable,  under  the  best  possible  arrangements,  to  obtain  any  thing 
like  the  same  mechanical  power  from  zinc  which  can  be  obtained  from  coal.  Zinc  burns  at 
an  elevated  temperature ;  in  burning  a  pound  of  zinc  there  should  be  obtained,  as  heat,  the 
same  amount  of  mechanical  power  which  is  obtained  as  electricity  in  the  battery.  The 
heat  being  more  easily  applied  as  a  prime  mover,  it  would  be  far  niore  economical  to  burn 
zinc  under  a  boiler,  and  to  use  it  for  generating  steam-power,  than  to  consume  zinc  in  a 
voltaic  batterv  for  generating  electro-magnetical  power. 

ELECTRO-PLATING  AND  GILDING  IRON.  Professor  Wood,  of  Springfield,  Mass., 
in  a  paper  which  he  has  communicated  to  the  Scientific  Awerhan,  recommends  the  follow- 
ing as  useful  recipes  for  the  electro-metallurgist.  Be  says  :  "  I  believe  it  is  the  first  time 
that  a  solution  for  plating  direct  on  iron,  steel,  or  Britannia  metal,  has  been  published.  In 
most  of  the  experiments  I  have  used  Smee's  battery ;  but  for  depositing  brass  I  prefer  a 
battery  fitted  up  as  Grove's,  using  artificial  graphite — obtained  from  the  inside  of  broken 
coal-gas  retorts — in  the  place  of  platinum.  With  one  large  cell,  (the  zinc  cylinder  being 
8x3  inches,  and  excited  with  a  mixture  of  one  part  sulphuric  acid  and  twelve  parts  water, 
the  graphite  being  excited  with  commercial  nitric  acid,)  I  have  plated  six  gross  of  polished 
iron  buckles  per  hour  with  brass.  I  have  also  coated  type  and  stereotype  plates  with  brass, 
and  find  it  more  durable  than  copper-facing." 

To  Prepare  Cymikle  of  Silver. — 1.  Dissolve  1  oz.  of  pure  silver  in  2  oz.  of  nitric  acid 
and  2  oz.  of  hot  water,  after  which  add  1  quart  of  hot  water.  2.  Dissolve  5  oz.  of  the 
cyanide  of  potassium  in  1  quart  of  water.  To  the  first  preparation  add  by  degrees  a  small 
portion  of  the  second  preparation,  until  the  whole  of  the  silver  is  precipitated,  which  may 
be  known  by  stirring  the  mixture  and  allowing  it  to  settle.  Then  drop  into  the  clear  liquid 
a  very  small  quantity  of  the  second  preparation  from  the  end  of  a  glass  rod  ;  if  the  clear 
liquid  is  rendered  turbid,  it  is  a  proof  that  the  whole  of  the  silver  is  not  separated  ;  if,  on 
the  other  hand,  the  liquid  is  not  altered,  it  is  a  proof  that  the  silver  is  separated.  The  clear 
liquid  is  now  to  be  poured  off,  and  the  precipitate,  which  is  the  cyanide  of  silver,  washed  at 
least  four  times  in  hot  water.  The  precipitate  may  now  be  dried  and  bottled  for  use.  To 
Prepare  Ci/anide  of  Gold. — Dissolve  1  oz.  of  fine  gold  in  1'4  oz.  of  nitric  acid  and  2  oz. 
of  muriatic  acid ;  after  it  is  dissolved,  add  1  quart  of  hot  water,  and  precipitate  with  the 
second  preparation,  proceeding  the  same  as  for  the  cyanide  of  silver.  7o  Prepare  C'l.'ati- 
ides  of  Copper  and  Zinc. — For  copper,  dissolve  1  oz.  of  sulphate  of  copper  in  1  pint  of  hot 
water.  For  zinc,  dissolve  1  oz.  of  the  sulphate  of  zinc  in  1  pint  of  hot  water,  and  iirocced 
the  same  as  for  cyanide  of  silver.  The  electro-plater,  to  insure  success  in  plating  upon  all 
metals  and  metallic  alloys,  must  have  two  solutions  of  silver ;  the  first  to  whiten  or  fix  the 
S'lver  to  such  metals  as  iron,  steel,  Britannia  metal,  and  German  silver;  the  second  to  finish 
the  work,  as  any  amount  of  silver  can  be  dei)osited  in  a  reguline  state  from  the  second  solu- 
tion. First.,  or  miiteiiing  Solution. — Dissolve  2^  lbs.  (troy)  of  cyanide  of  potassium,  8 
oz.  carbonate  of  soda,  and  3  oz.  cyanide  of  silver  in  one  gallon  of  rain  or  distilled  water. 
This  .solution  should  be  used  with  a  compound  battery,  of  three  to  ten  pairs,  according  to 
the  size  of  the  work  to  be  plated.  Second,  or  Finishinci  Solution.—  Dissolve  4-^  oz.  (troy) 
of  cyanide  of  potassium,  and  \h  oz.  of  cyanide  of  silver,  in  1  gallon  of  rain  or  distilled 
water.  This  solution  should  be  used  with  one  large  cell  of  Smee's  batterv,  observing  that 
the  silver  plate  is  placed  as  near  the  surface  of  the  articles  to  be  plated  as  possible. — 
N.  B.  By  using  the  first,  or  whitening  solution,  you  may  insure  the  adhesion  of  silver  to  all 
kinds  of  brass,  bronze,  red  cock  metal,  type  metal,  &c.,  without  the  use  of  mercury,  which 
is  so  injurious  to  the  human  system.  To  Prepare  a  Solution  of  Gold — Dissolve  4  oz. 
(troy)  of  cyanide  of  potassium,  and  1  oz.  of  cyanide  of  gold,  in  1  gallon  of  rain  or  dis- 
tilled water.     This  solution  is  to  be  used  warm,  (about  90'  Fahr.,)  with  a  battery  of  at  least 


ELECTRO-TELEGKAPHY.  499 

two  cells.  Gold  can  be  deposited  of  various  shades  to  suit  the  artist,  by  adding  to  the  solu- 
tion of  gold  a  small  quantity  of  the  cyanides  of  silver,  copper,  or  zinc,  and  a  few  drops  of 
the  hydro-sulphuret  of  ammonia. 

ELECTRO-SORTING  APPARATUS.  M.  Fromcnt  has  devised  an  apparatus  for  the 
separation  of  iron  from  matters  by  which  it  may  be  accompanied.  The  apparatus  consists 
of  a  wheel  carrying  on  its  circumference  eighteen  electro-magnets.  The  iron  ore  reduced 
and  pulverized  is  spread  continually  upon  one  of  the  extremities  of  a  cloth  drawn  along 
with  it,  and  passed  under  the  electro-magnets  in  motion.  The  iron  in  the  ore,  which  has  of 
course  been  brought  into  a  magnetic  state  by  any  of  the  processes  by  which  this  may  be 
effected,  is  separated  by  the  magnets,  and  the  impurities  carried  onward.  See  De  la  Rive's 
Electricity. 

ELECTRO-TELEGRAPHY.  It  would  far  exceed  our  limits  were  we  to  attempt  the 
most  hurried  sketch  of  the  history  of  this  art ;  we  shall  therefore  content  ourselves  with 
illustrating  the  leading  doctrines  that  have  been  realized  in  the  telegraph  systems  which  are 
most  in  favor  at  the  time  in  which  we  write. 

Locked  up,  as  it  were,  in  all  bodies,  is  a  large  store  of  electric  force,  the  equilibrium  of 
which  is  disturbed  in  a  greater  or  less  degree  by  a  variety  of  causes,  some  extremely  simple, 
others  more  complex ;  and,  according  as  one  or  other  cause  is  in  operation,  the  conditions 
under  which  the  electric  force  is  manifested  vary ;  some  conditions  being  very  unfavorable, 
and  others  very  favorable  to  the  object  in  view. 

Friction  is  a  well-known  means  of  producing  electric  effects.  Amber  (in  Greek,  elec- 
tron) was  the  first  substance  on  which  they  were  noticed  in  a  special  manner,  and  hence  the 
name.  Light  bodies,  such  as  gold  leaf,  or  feathers,  are  attracted  by  rubbed  amber ;  the 
leaf  gold  is  quickly  repelled  again,  the  feathers  not  so  readily.  In  due  course  it  was  dis- 
covered that  this  difference  of  behavior  is  due  to  the  gold  conducting  electricity,  and  the 
feathers  not  so  ;  the  one  allowing  the  force  to  diffuse  itself  about  it,  the  other  receiving  and 
retaining  it  only  in  or  near  the  points  of  contact ;  if  the  former  property  were  universal, 
it  would  be  impossible  to  collect  electricity  ;  if  the  latter,  it  would  be  impossible  to  get  rid 
of  it.  Oondnction  is  well  illustrated  and  turned  to  useful  account  in  the  iron  and  copper 
wires,  by  which  distant  telegraph  stations  are  connected  with  each  other;  insulation^  by  the 
glass  or  porcelain  articles  with  which  the  said  conducting  wires  are  suspended  to  the  poles 
above  ground,  and  by  the  gutta  percha  with  which  the  subterranean  or  submarine  wires  are 
covered. 

The  rapidity  with  which  electric  force  traverses  conductors  depends  upon  the  circum- 
stances under  which  the  conductors  are  placed ;  in  one  case,  as  in  that  of  wire  suspended 
iu  the  air,  the  electric  force  has  little  else  to  do  than  to  travel  onward  and  be  discharged 
from  the  far  end  of  the  wire  ;  in  the  other  case,  as  in  that  of  buried  wire,  it  has  to  disturb 
the  electric  equilibrium  of  the  gutta  percha  as  it  travels  onward,  and  thus  suffers  consid- 
erable retardation.  The  greatest  recorded  velocity  of  a  signal  through  a  suspended  copper 
telegraph  wire,  is  1, '752, 800  miles  per  second,  by  M.  Hipp ;  the  lowest  velocity  through  a 
buried  copper  wire,  750  miles  per  second  by  Faraday.  Intermediate  velocities  are  recorded, 
for  which  the  nature  of  the  wire  or  the  conditions  under  which  it  was  placed  were  different. 
Wheatstone  found  the  velocity  of  electricity  under  different  conditions  from  the  above  to 
be  288,000  miles  per  second.  His  wire  was  copper,  and  was  wound  on  a  frame.  The  elec- 
tricity that  was  employed  by  Mr.  Wheatstone  in  these  experiments  was  obtained  from  the 
friction  of  glass  against  an  amalgam  of  tin.  The  various  velocities  are  due  partly  to  the 
conditions  under  which  the  conducting  wire  is  placed,  and  partly,  no  doubt,  to  the  varied 
properties  of  electricity  from  various  sources.  And  the  very  different  methods  of  reading 
off  the  velocities  in  this  and  in  other  cases  may  have  an  influence  over  the  respective 
values. 

Electricity  is  obtained  from  other  sources  than  friction  with  so  much  greater  facility,  and 
in  forms  so  mucli  more  applicable  and  manageable  for  telegraphic  purposes,  that  frictional 
electricity  has  not  been  applied  in  real  practice.  It  must  not,  however,  be  passed  over  in  this 
place,  because  one  of  the  earliest  telegraphs,  perhaps  the  very  first  in  whicli  a  long  length  of 
wire  was  actually  used,  was  actuated  by  this  form  of  electricity.  In  ISlC),  Mr.  Ronalds  estab- 
lished, in  the  grounds  attached  to  his  residence  at  Hammersmith,  eight  miles  of  wire  sus- 
pended by  silk  to  dry  wood,  besides  175  yards  of  buried  wire  in  glass  tubes  embedded  in 
pitch  and  enclosed  in  troughs  of  wood.  He  obtained  his  electricity  from  a  common  elec- 
trical machine,  and  his  signals  from  the  motion  of  light  bodies,  lialls  of  eliler  pith,  produced 
under  circumstances  analogous  to  those  to  which  we  have  already  referred.  At  the  far  end 
of  his  telegraph  wire  two  pith  Ijalls  were  suspended  close  together.  Electricity  applied  at 
the  home  end  of  the  wire  at  once  diffused  itself  throughout  the  conducting  system,  inilud- 
ing  the  pair  of  light  balls.  Just  as  we  have  seen  gold  leaf  recede  after  having  apjiroachcd 
rubbed  amber,  and  acquired  an  electric  charge,  so  the  pith  balls,  each  being  charged  with 
electricity,  derived  from  the  same  source,  recede  from  each  other ;  and  this  in  obedience  to 
the  fundamental  laws  of  static  electricity,  for  which  we  must  refer  readers  to  treatises  on 
the  subject.     Here,  then,  we  have  one  solitary  signal.     The  manner  in  which  Mr.  Ronalds 


500  ELECTRO-TELEGRAPHY. 

turned  it  into  language  was  ingenious.  He  pressed  time  into  his  service,  and  by  combining 
time  and  motion  he  obtained  a  language.  He  provided  a  clock  movement  at  each  htation  ; 
the  clocks  were  so  regulated  as  to  be  synchronous  in  their  movements ;  each  of  them  car- 
ried, in  lieu  of  a  hand,  a  light  disc,  having  the  letters  of  the  alphabet  and  other  signals  en- 
graved on  it.  The  disc  was  hidden  by  a  screen,  in  which  was  one  opening.  It  is  obvious 
that  if  the  clocks  were  started  together,  and  had  uniform  rates,  the  same  letter  at  the  same 
time  would  be  visible  through  the  opening  in  each  screen  ;  and  letter  by  letter  would  pass 
seriatim  and  simultaneously  before  the  respective  openings.  If  absolute  uniformity  is  diffi- 
cult for  long  periods,  it  is  practicable  for  shorter.  The  sender  of  a  message  watched  the 
opening  of  his  screen  ;  the  moment  the  letter  approached  that  he  desired  to  telegraph,  he 
charged  the  wire  with  electricity,  and  the  balls  at  the  far  station  moved ;  the  letter  then 
visible  there  corresponded  with  the  one  at  the  home  station,  and  was  read  off.  The  sender 
watched  till  the  next  letter  he  required  came  round,  and  so  on. 

Let  us  now  pass  on  to  some  of  the  leading  features  of  electro-telegraphy,  as  it  has  been 
realized  of  late  years,  and  to  a  description  of  some  of  the  telegraph  instruments  that  are 
most  in  use. 

Chemical  action  is  the  most  fertile  source  of  electricity.  If  a  silver  fork  and  a  steel 
knife  are  connected  together  by  a  piece  of  wire,  and  the  fork  is  thrust  into  a  piece  of  meat, 
say  a  hot  mutton  chop,  the  moment  an  incision  is  made  in  the  meat  with  the  knife,  elec- 
tricity will  iiass  along  the  wire,  and  continue  to  do  so  while  the  above  disposition  of  things 
remains.  Upon  the  proper  test  being  applied,  the  electricity  is  readily  detected.  This  is 
the  current  form  of  electricity.  The  amount  of  force  in  circulation  in  tliis  particular  com- 
bination is  not  very  great,  and  its  power  of  travelling  to  a  distance  is  not  very  high,  but 
still  it  is  quite  capable  of  producing  good  signals,  on  a  delicate  airangemcnt  of  the  needle 
instrument,  (of  which  more  hereafter,)  with  which  in  England  we  are  so  familiar. 

The  amount  of  electricity  obtained  by  means  of  chemical  action,  is  increased  to  the 
required  extent  by  a  judicious  selection  of  metals,  and  of  the  liquid  or  liquids  in  which  they 
are  immersed.  Zinc  is  invariably  used  as  one  of  the  metals  ;  it  is  represented  by  the  iron 
of  the  knife  in  the  above  experiment.  Copper,  silver,  and  platinum  or  graphite,  (gas  car- 
bon,) is  selected  for  the  other  metal.  When  the  two  metals  are  immersed  in  a  same  liquid, 
a  mixture  of  sulphuric  acid  with  salt-water,  or  fresh,  is  employed.  When  two  liquids  are 
used,  they  are  separated  by  a  porous  partition  ;  the  zinc  is  usually  placed  in  the  sulphuric 
acid  solution,  and  the  other  metal  in  a  solution  varying  with  the  nature  of  the  arrangements 
proposed.  Zinc  is  naturally  soluble  in  the  acid  solution  in  question  ;  and  would  therefore 
waste  away  and  be  consumed  at  the  expense  also  of  the  acid,  unless  precautions  were  taken 
to  make  it  resist  the  ordinary  action  of  the  solvent.  When  zinc  is  dissolved  in  mercury  it 
is  not  attacked,  under  ordinary  circumstances,  by  sulphuric  acid  solution.  Hence  the  plates 
of  zinc  employed  in  all  good  voltaic  combinations,  as  they  are  called,  into  which  this  acid, 
in  a  free  state,  enters,  are  protected  by  being  well  amalgamated ;  that  is,  they  are  dipped 
in  a  strong  acid  mixture  and  well  washed  ;  and  are  then  dipped  into  a  mercury  bath,  and 
are  placed  aside  to  drain.  The  operation  is  generally  repeated  a  second  time  ;  and,  in  the 
best  arrangements,  the  further  precaution  is  taken  of  standing  the  zinc  plate,  while  in  the 
acid  water,  in  some  loose  mercury,  placed  either  in  the  bottom  of  the  containing  vessel,  or 
in  a  gutta  percha  cell :  by  the  latter  arrangement,  mercury  is  economized.  In  single  liquid 
arrangements,  it  is  dcsiral)lc  to  select  a  metal  that  is  not  attacked  by  the  acid.  Copper  has 
been  extensively  used,  and  is  very  valuable ;  but  it  possesses  the  defect  of  being  slowly 
attackable.  The  waste,  however,  that  it  suffers  in  itself  from  this  cause,  is  of  small  mo- 
ment compared  with  certain  secondary  results,  which  terminate  in  the  consumption  of  the 
acid  and  the  zinc,  and  the  destruction  of  the  functions  of  the  apparatus.  Gold  and  platinum 
are  free  from  these  defects,  but  are  too  costly.  Silver  is  to  a  great  extent  free  from  tlicni, 
and  has  been  much  and  successfully  used,  especially  when  platinized ;  that  is,  having  its 
surface  covered  with  finely  divided  powder  of  platinum.  The  corrosion  from  gas  retorts, 
cut  into  plates,  and  similarly  treated,  forms  with  amalgamated  zinc  one  of  the  cheapest  and 
most  effective  combinations. 

A  single  pair  of  plates,  no  matter  what  their  character,  is  unable  to  produce  a  force  thr.t 
can  overcome  the  resistance  of  a  wire  of  any  length,  and  produce  an  available  result  at  a 
distant  station  ;  and  hence  a  series  of  pairs  is  employed  in  the  telegraphic  arrangements. 
K  (_/fy.  2C8)  represents  a  common  mode  of  arranging  a  series  of  pairs  of  plates.  It  con- 
sists of  a  wooden  trough  made  water-tight,  and  divided  into  water-tight  cells.  The  metals 
are  connected  in  pairs  by  copper  bands  ;  each  pair  is  placed  astride  over  a  partition,  and 
all  the  zincs  face  one  way.  When  the  plates  (copper-zinc)  are  placed  in,  and  the  cells  are 
filled  up  with  pure  white  sand,  and  the  acid  water  poured  in,  we  have  the  very  portable  battery 
that  was  originally  used  by  Mr.  Cooke,  and  is  still  much  employed  in  England.  When  bat- 
teries of  a  higher  class  are  employed,  the  cells  are  distinct  pots  or  jars ;  and  great  precau- 
tions arc  taken  to  prevent  any  conducting  communication  existing  between  the  neighboring 
cells,  save  by  means  of  the  copper  band.  In  the  trough  form  there  is  a  leakage  and  loss 
of  force  from  cell  to  cell.     The  c  or  copper  is  the  positive  end  of  such  a  series,  and  the  z 


ELECTRO-TELEGRAPHY. 


501 


or  zinc,  the  negative  ;  and  both  are  in  a  condition  to  discharge,  citlier  each  to  the  other,  by 
means  of  a  wire  led  from  one  to  the  other,  or  eacli  to  the  earth,  one  by  a  wire  leading  to 
the  earth  at  tlie  place  where  the  battery  stands,  and  the  other  by  a  long  wire  (say  a  tele- 
graph wire)  leading  to  the  earth  at  a  distant  place.  The  resistance  to  be  overcome  is,  in 
the  former  case,  less ;  and  the  current  of  force  in  cireiihuion  is  proportionately  greater. 
Under  whatever  circumstances  a  wire  takes  part  in  promoting  the  discharge  of  an  apparatus 
of  this  kind,  the  whole  of  the  said  wire  is  in  a  condition  to  indicate  the  presence  of  the 
force  that  is  pervading  it ; 
and   as   the   force   may  be  268 

presented    to    the   wire   in  _„ -^. 

either  of  two  directions, 
that  is  to  say,  the  copper 
or  the  zinc,  namely,  the 
positive  or  the  negative  end 
of  the  battery,  may  be  pre- 
sented to  the  given  end  of 
the  telegraph  wire,  the  rela- 
tive condition  of  the  wire 
will  be  modified  according- 
\y.  Not  only  can  the  direc- 
tion of  this  current  force  be 
inverted  at  pleasure,  but  it 
can  be  maintained  for  any 
length  of  time,  great  or 
small,  and  in  either  direc- 
tion. This  is  accomplished 
by  various  mechanical  ar- 
rangements, which  are  the 
keys,  commutators,  or  han- 
dles of  the  various  telegraph 
instruments,  (of  which  more 
hereafter,)  and  are  often  the 
only  part  presenting  any 
complexity  about  them.  In 
j!;/.  268,  the  source  of  elec- 
tricity, E,  we  have  already 
described  ;  the  test-instru- 
ment for  the  abnormal  state 
of  the  wire,  that  is  to  say, 
the  telegraph  proper,  is  the 
part  A.  The  complex  part, 
consisting  of  springs,  cylin- 
ders, and  studs,  shown  be- 
low A,  is  nothing  more  than 

the  necessary  mechanical  arrangement  for  directing  at  pleasure  tlie  current  from  the  bat- 
tery E,  in  either  direction  through  the  wire,  and  through  the  part  a.  By  following  the  let- 
ters in  the  order  here  given,  the  course  of  the  current  may  be  traced  from  its  leaving,  say 
the  positive  or  copper  end  of  the  battery,  till  its  return  to  the  zinc  or  negative  end ;  c  c'  d 
vr  w  u  A  z'  6  B  z.  If  a  companion  instrument  were  in  any  part  of  the  circuit  of  the  wire 
w  \v,  it  would  correspond  in  its  signals  with  the  home  instrument,  fir/.  268. 

One  of  the  properties  possessed  by  a  wire,  during  the  act  of  discharging  a  voltaic  bat- 
tery, is  to  deflect  a  magnetized  needle.  If  the  two  are  parallel  in  the  normal  state  of  the 
wire,  the  needle  is  deflected  this  way  or  that,  when  the  wire  is  in  the  abnormal  state  ;  and 
if  the  needle  is  very  delicate,  and  a  large  enough  amount  of  electricity  is  circulating  through 
the  wire,  the  needle  reaches  the  maximum  deflection  of  90°.  This  is  an  extreme  case,  and 
cannot  be  approached  in  practice.  Indeed,  the  deflection  of  any  ordinary  needle,  under  the 
action  of  an  ordinary  telegraph  wire,  would  not  be  appreciable.  But,  as  crcri/  foot  of  the 
wire  has  the  same  amount  of  reaction,  we  have  merely  so  to  arrange  things  that  many  feet — 
a  long  length  of  the  wire — shall  be  made  to  react  upon  the  needle  at  the  same  time,  and 
thus  the  effect  is  multiplied  in  proportion  to  the  length  of  wire  so  concentrated.  This  is 
managed  by  covering  a  considerable  quantity  of  fine  wire  with  silk  or  cotton,  and  winding 
it  on  a  frame  a,  (_/?//.  268,)  suspending  the  needle  within  the  frame.  Such  an  instrument  is 
called,  from  its  properties,  a  mulfiplier.  It  is  seen  at  a  glance  that  the  wire  of  the  multi- 
plier is  an  aillilion  over  and  above  the  length  of  the  actual  telegraph  wire  recjuircd  for 
reaching  the  distant  station,  and  thu'^  it  practically  increases  the  distance  to  l)e  traversed  : 
its  smallness  adds  to  this.  The  multipliers  connnonly  used  add  a  resistance  equal  to  six  or 
seven  miles  of  telegraph  wire. 


502 


ELECTRO-TELEGRAPHY. 


Let  us  now  turn  to  the  face  of  the  instrument  Here 
which  IS  on  the  same  axis  as  the  n.agnetized  needle  above 
fle<;ted  to  the  right  or  left,  and  limited  in 
Its  motion  by  ivory  pins.  We  have  a  handle 
lor  working  the  mechanical  part  so  con- 
nected that,  as  it  moves  to  the  right  it 
directs  a  current  into  the  wire  such  that 
the  needle  moves  to  the  right,  and  vice 
versa.  An  alphabet  is  constructed  from 
the  combination  of  these  two  elementary 
motions,  one  or  more  of  either  or  both 
kinds  ol  deflection  being  used  for  the  va- 
rious letters,  as  sliown  on  the  engraved 
dial.  1  lis  is  Cooke  and  Wheatstone's  sin- 
gle needle  instrument.  Jiff.  269. 

The  form  and  cliaracter  of  their  double 
needle  instrument  is  shown  in  fiq  270  It 
IS  precisely  a  duplicate  of  the  former  ;'  two 
handles,  and  their  respective  springs,  studs 
and  cylinders,  two  multipliers,  and  two 
magnetized  needles,  with  their  external  in- 
dexes and  two  telegraph  wires.  One  bat- 
tery, however,  is  sufficient.  One  or  more 
of  either  or  both  kinds  of  deflection  of 
eitlier  or  both  needles,  accordiii"-  to  the 
code  engraved  on  the  dial,  constitutes  the 
alphabet.  This  instrument  is  very  exten- 
sively emjiloyed ;  messages  are  sent  by  it 
witli  extreme  rapidity. 

Another  property  possessed  by  a  wire 
conveying  a  current,  is  that  of  converting 


we  have  a  dial  and 
described,  capable  of 


an  index, 
being  de- 


ELECTEO-TELEGRAPHY. 


503 


soft  iron,  for  the  time,  into  a  magnet.  Tiie  attractive  power,  which  can  thus  be  given  to, 
and  withdrawn  from,  the  soft  iron  at  pleasure,  is  turned  to  useful  account,  either  in  produc- 
ing direct  mechanical  action,  or  in  liberating  the  detents  of  a  clock  movement.  Here  also 
the  effect  of  the  solitary  wire  is  inappreciable,  and  many  convolutions  around  the  iron  are 
necessary  in  order  to  obtain  a  useful  result. 

The  simplest  application  of  this  principle  is  shown  in  Jig.  271.  Here  are  two  brass 
reels,  filled  with  cotton-covered  copper  wire,  in  one  length.  They  are  hollow,  and  a  U- 
sliaped  bar  of  iron  passes  through 

them,  presenting  its  ends  at  the  - '  ^ 

face  turned  toward  us  in  the  draw- 
in,'.  This  bar  becomes  magnetic 
—  forms  what  is  called  an  electro- 
magnet— every  time  and  as  long 
as  an  electrical  current  circulates 
in  the  wire ;  and  its  ends  be- 
come respectively  north  and  south 
poles.  A  narrow  plate  of  iron, 
an  armature,  as  it  is  termed,  is 
mounted  on  pivots  in  front  of  the 
ends  or  poles  of  the  magnet ;  it 
carries  a  vertical  stem  upon  which 
the  hammer  is  fixed.  Every  time 
the  iron  bar  is  magnetic  the  arma- 
ture is  attracted,  and  the  hammer 
strikes  the  bell.  The  spring  or 
contact-maker  for  introducing  the 
current  of  electricity  into  the  cir- 
cuit, is  shown  in  front  on  the 
right-hand  side.  This  is  Mr.  Walker's  bell  for  signalling  railway  trains  from  station  to  sta- 
tion. The  language  consists  of  o:ie  or  more  blows.  One,  two,  and  three  blows,  are  the 
signals  for  common  purposes  ;  half  a  dozen  blows  is  the  limit.  The  acknowledgment  of  a 
signal  is  its  repetition.  By  a  simple  arrangement  of  an  inde.x,  that  moves  in  fellowship 
with  the  hammer,  the  eye,  as  well  as  the  ear,  may  read  the  bell-signals. 

Fig.  272  shows  another  application  of  the  direct  action  of  an  electro-magnet  in  produc- 

272 


l^m^^ 


ing  telegraph  signals.  It  is  Morse's  printing  telegraph,  very  generally  used  in  America,  and 
used  to  no  small  extent  in  Europe.  The  coils  of  wire  are  shown  at  m,  the  armature  at  ii, 
fixed  at  one  end  of  tlie  lever  p,  which  is  itself  carried  on  centres  at  <•.  The  range  of  mo- 
tion here  is  small  in  order  to  produce  rapid  utterance ;  it  is  regulated  by  the  screws  d  ami  i. 
The  reaction  of  the  spiral  spring  /  restores  the  lever  to  its  normal  position  each  time  the 
magnetism  ceases.  The  signals  consist  of  dots  or  dashes,  variously  combined,  made  by  the 
pointed  screw  t  upon  the  slip  of  paper  p,  running  from  the  drum  at  the  right  in  the  direc- 
tion of  the  arrows;  a  few  such  signals  are  shown  u[)on  the  end  of  the  paper  slip.  Wc  have 
described  the  telegraph  proper,  which  is  seen  to  be  extremely  simple.  The  only  parts  at 
all  complex  are,  as  with  the  needle  instruments  already  deseril)ed,  the  mechanical  parts, 
namely,  the  train  of  wheels  for  carrying  on  the  paper  band,  and  the  key  or  contact-maker, 
not  shown  in  the  figure.     The  amount  of  pressure  required  from  the  point  t  in  order  to 


504 


ELECTRO-TELEGRAPHY. 


produce  a  mark,  is  such  that  it  cannot  conveniently  be  produced  hy  tlie  magnetic  attraction 
derived  from  a  current  of  electricity  that  has  come  from  a  far  distant  station  in  order  to 
circulate  in  the  coils  of  wire  m.  This  dilficulty  does  not  prevail  in  the  signal-bells,  fig. 
271,  which  are,  at  most,  not  required  to  be  more  than  eight  or  ten  miles  apart,  and  in  which 
also  momentum  can  be  and  is  accumulated  so  as  to  conspire  in  producing  the  final  result. 
Morse  has,  therefore,  had  recourse  to  a  rela;/,  as  he  calls  it.  This,  in  ])rinciple,  is  pictty 
much  the  same  thing  as  the  instrument  itself ;  but  it  has  no  heavy  work  to  do,  no  marks  to 
make  ;  it  has  merely  to  act  the  part  of  a  C(mtact-maker  or  key  ;  it  can  hence  he  made  very 
delicate,  so  as  to  act  well  by  such  currents  as  would  not  produce  any  motion  in  the  instru- 
ment itself.  The  batteries  which  furnish  the  electricity  lor  doing  the  actual  printing  work 
in  Morse's  telegraph,  are  in  the  same  station  with  the  instrument  itself.  The  office  of  the 
relay  is  to  receive  the  signals  from  afar,  and  to  make  the  necessary  connections  with  the 
local  battery  and  instrument  so  as  to  print  off  the  signals  on  the  paper  in  the  usual  wny. 
It  is  obvious  that  the  motions  of  the  instrument  and  the  relay  are  sympathetic,  and  that 
what  a  trained  eye  can  read  off  from  the  one,  a  trained  ear  can  read  off  from  the  othir. 
The  relays  are  constructed  with  much  finer  wire  than  is  required  for  the  instrument  itself, 
so  that  the  current  circulating  in  them,  although  very  low  in  force,  is  multiplied  by  a  very 
high  number,  and  becomes  equal  to  the  delicate  duty  required  of  it. 

Fig.  273  is  another  illustration  of  the  direct  application  of  the  electro-magnet  without 


adventitious  aid.  It  represents  a  detent  of  McCallum's  Globotype  for  recording  signals. 
The  long  tube  contains  small  glass  balls,  which  are  retained  therein  by  a  detent  attached  to 
the  armature  of  an  electro-magnet.  Every  time  the  armature  is  attracted,  one  ball  is  liber- 
ated and  runs  down  into  a  grooved  dial,  where  it  remains  for  inspection.  One  or  more 
tubes  and  detents  are  used,  according  to  the  nature  of  the  signal  required.  As  applied  to 
the  signal-bell,  {fg.  271,)  three  tubes  are  used — one  charged  with  black  balls,  for  indicating 
the  number  of  bell  strokes  made ;  one  with  white  balls,  for  indicating  the  bell-signals  sent ; 

one  with  spotted  balls,  for  marking  off  the  time  in  quar- 
- '  ^  ters  of  hours  or  intervals  of  less  length.     The  balls,  when 

liberated,  all  run  into  the  same  dial,  and  arrange  them- 
selves seriatim. 

We  may  here  refer  to  the  case  of  another  bell  or 
alarum,  in  which  the  magnetic  attraction  derived  from  the 
current  that  arrives,  is  not  equal  to  the  mechanical  work 
of  striking  a  blow  and  sounding  a  bell,  but  which  is  able 
to  raise  a  detent,  that  had  restrained  a  train  of  wheels, 
and  so  allow  the  mechanism  of  the  latter  to  do  the  work 
required.  This  arrangement  is  shown  in  Cooke  and  Wheat- 
stone's  alarum.  Jig.  274  ;  t  is  the  bell ;  in  m  is  the  double- 
headed  hammer,  which  is  in  fact  the  pendulum,  attached 
to  the  pallets  /",  which  work  in  a  scapc-wlieel  hidden  in 
the  figure,  and  in  gear  in  the  usual  way  with  a  coiled  spring 
in  the  box  h,  by  the  train  r,,  j-j,  rs,  >•■:.  The  electro-mag- 
netic part  here,  as  in  other  instruments,  is  simple  enough  ; 
rt  r  is  a  lever  moving  on  a  centre  above  /,  having  at  one 
end  an  armature  n^  facing  the  poles  of  the  electro-mngnct 
c  \  and  at  the  other  end  r,  a  hook  which  facCs  the  wheel  ?•, 
and  by  catching  in  a  notch  on  its  circumference,  keeps 
the  train  at  rest.  But  when  a  current  circulates  through 
the  coils  r,  the  armature  is  attracted,  the  hook  is  raised, 
the  train  is  liberated,  and  the  pendulum-hammer  vibrates 
and  strikes  a  succession  of  blows,  r  is  a  support  carrying  a  small  spring,  which  reacts  on 
the  lever,  and  restores  it  to  its  normal  position  when  the  mngnetism  ceases.  This  alarum  is 
used  for  calling  the  attention  of  telegraph  clerks.  It  requires  a  little  attention  to  keep  up 
the  proper  adjustment  between  the  spring  on  the  one  hand,  and  the  magnetic  attraction  on 
the  other. 


ELECTEO-TELEGRAPHY. 


505 


The  telegraph  originally  adopted  and  still  largely  used  by  the  French  Administration,  is 
somewhat  akin  to  the  ahirum  just  described.  It  has  a  train  of  wheels,  a  scape-wheel  with 
four  tectli,  and  a  pair  of  pallets.  There  is,  however,  no  pendulum  ;  Ijut  the  pallets  are  con- 
nected with  the  armature  of  an  electro-magnet,  in  such  a  manner  that,  for  each  attraction 
or  repuls'oii  of  the  armature,  the  scape-wheel  is  liberated  half  a  tooth  ;  for  an  attraction 
and  a  repulsion,  a  whole  tooth  ;  so  that  four  successive  currents,  producing  of  course  four 
consecutive  attractions  and  repulsions,  produce  a  whole  revolution  of  the  scape-wheel.  Tiie 
axis  of  the  latter  projects  through  the  dial  of  the  instrument,  {Jig.  275,)  and  carries  an  arm 

275 


a  or  b,  (  fig.  276,)  which,  following  the  motion  of  the  wheel,  is  able  to  assume  eight  distinct 
positions.  The  apparatrus  is  generally  double,  as  shown  in  the  figure ;  and  the  signals  are 
made  up  of  the  various  combinations  of  the  eight  positions  of  each  of  the  two  arms.  The 
arm  is  half  black,  the  other  half  white.  The  position  of  the  black  portion  is  read  off;  the 
white  portion  is  merely  a  counterpoise.  When  only  one  half  of  the  dial,  or  one  index,  is 
in  use,  the  combinations  are  shown  by  producing  with  the  one  index  successively  the  posi- 
tions of  the  two,  whose  combination  makes  the  signal,  always  giving  first  the  position  of 
the  left  hand  index,  then  that  of  the  right.  The  handles  shown  in  front  are  the  contact- 
makers,  and  are  so  constructed  that  the  position  of  the  arm  on  the  dial  coincides  with  the 
position  given  to  the  handle,     tig.  276  is 

a  front  view  of  the  two  arms  ;   part  of  the  276 

dial  is  supposed  to  be  removed,  so  as  to  ex- 
pose the  four-toothed  wheel  already  men- 
tioneil,  and  the  pallets  x  and  .; ;  which,  in 
their  movement  to  and  fro,  allow  of  the 
seaii-tooth  advances  of  the  wheel. 

In  these  various  applications  of  the  elec- 
tro-magnet, the  armature  has  been  of  soft 
iron,  and  the  only  action  of  the  electro-mag- 
net has  been  to  attract  it.  It  has  been 
withdrawn  from  the  magnet  after  the  elec- 
tricity has  ceased  to  circulate,  either  by  its  own  gravity,  by  a  counterpoise,  or  by  a  reacting 
spring.  We  now  come  to  a  telegraph  that  is  well  known  and  much  used — Henley's  mag- 
neto-electric telegraph,  in  which  there  is  no  reacting  spring ;  and  in  which  the  movement 
or  signal  is  produced  by  the  joint  action  of  attraction  and  repulsion,  and  the  return  to  its 
normal  state  by  the  same  joint  action.  Each  pole  of  Henley's  electro-magnet  has  a  double 
instead  of  the  single  termination,  that  we  have  been  considering  in  all  preceding  cases.  A 
piece  of  soft  iron,  like  a  crescent,  is  screwed  upon  eacii  of  the  poles ;  the  horns  or  cusps 
of  the  respective  crescents  are  facing  and  near  to  each  other  ;  and  a  magnetized  steel  needle 
is  l)alanced  between  thein.  This  arrangement  is  scunewhat  like  the  following  (  |  ).  So 
long  as  no  current  is  circulating  in  the  coils  of  the  electro-magnet,  the  cn-scents  are  impas- 
sive soft  iron,  and  no  one  point  of  either  of  them  has  more  tendency  than  any  other  point 
to  attract  either  end  of  the  magnetized  needle  that  is  between  them.  But  while  a  current 
is  circulating,  one  of  the  crescents  is  endowed  with  north  magnetic  polarity,  which  is  espe- 
cially developed  at  its  horns,  and  the  other  with  south  polarity.     Suppose  the  horns  of  the 


L 


50G 


ELECTRO-TELEGEAPHY. 


right-hand  crescent  are  north  poles,  those  of  the  left  south  poles,  and  the  top  end  of  the 
needle  is  north.  Four  forces  will  conspire  to  move  the  needle  to  the  left.  Its  top  will  be 
attracted  by  the  left-hand  crescent  and  repelled  by  the  right ;  its  bottom  will  be  repelled  bv 
the  left,  and  attracted  by  the  right.  When  this  current  ceases  to  circulate,  the  simple 
attraction  between  the  magnetized  needle  and  the  soft  iron  of  the  crescent  tends  to  retain 
it  in  a  deflected  position.  This  tendency  is  increased  by  a  little  residual  magnetism,  that  is 
apt  to  remain  in  the  best  iron,  notwithstanding  every  care  in  its  preparation.  In  order, 
therefore,  to  restore  the  needle  to  its  normal  position,  a  short  quick  current  in  the  reverse 
direction  is  given.  These  instruments  are  single  or  double.  Only  one  kind  of  deflection 
of  the  needle  is  available  for  actual  signals,  the  other  motion  being  merely  the  return  to  the 
normal  state.  The  single  needle  alphabet  is  composed  of  deflections  of  a  short  or  a  long 
duration  ;  these  are  produced  by  holding  on  the  current  for  an  instant  or  for  more  than  an 
instant ;  and  the  various  combinations  of  short  and  long  correspond  to  Morse's  dot  and  dash 
system.  The  double  needle  alphabet  consists  of  combinations  of  the  deflection  of  either 
or  both  needles. 

Fig.  277  shows  Henley's  instrument,  and,  in  completing  the  description  of  it,  we  have 

277 


to  describe  another  source  of  electric  current  to  which  no  allusion  has  been  hitherto  made. 
The  electricity  here  employed  is  obtained  neither  by  friction  nor  by  chemical  action,  but  by 
means  of  magnetism  a7id  motion.  If  a  piece  of  metal  is  moved  in  the  presence  of  a  mag- 
net, or  a  magnet  is  moved  in  presence  of  a  piece  of  metal,  a  current  of  electricity  is  gen- 
erated in  the  metal.  The  results  are  multiplied  when  the  metal  is  a  coil  of  covered  wire  ; 
so  that  we  have  here  the  converse  of  the  electro-magnet ;  in  the  one  case  electricity  had 
produced  magnetism,  in  the  other  magnetism  produces  electricity ;  hence  the  name  mcKj- 
nelo-elcrtric  telegraph.  We  have  here  a  powerful  set  of  steel  magnets  a  a,  all  the  north 
ends  pointing  in  one  direction,  and  bound  together  with  a  plate  of  iron,  and  all  the  .south 
ends  similarly  arranged  in  the  other  direction.  Facing  each  end,  but  not  quite  in  front 
when  at  rest,  is  an  electro-magnet  proper,  B  b,  consisting  of  the  U-shaped  iron  rod  and  the 
coil  of  covered  wire,  as  described  in  fy.  271.  Each  electro-magnet  is  mounted  upon  an 
axis,  c  is  a  short  lever  or  key  ;  on  depressing  this,  the  electro-magnet  moves  from  its  nor- 
mal position  in  a  region  of  lesser  magnetic  force,  into  a  new  position  in  the  region  of  great- 
est magnetic  force,  and  thus  is  the  double  condition,  enunciated  above,  complied  with  /the 
copper  wire  is  moved  in  the  presence  of  a  magnet,  and  this  under  the  most  favorable  con- 
ditions ;  and  the  TJ  iron,  rising  from  a  feeble  to  a  strong  magnet,  its  lines  of  magnetic  force 
move  in  presence  of  the  copper  wire.  Just  as  a  current,  coining  from  a  long  distance,  had 
to  be  received  in  Morse's  arrangement  [fg.  272)  in  an  electro-magnet  of  a  long  coil  of  fine 
wire,  so  as  to  be  much  multiplied  in  order  to  do  its  work,  so  here  a  magneto-electric  cur- 
rent, that  has  to  be  sent  to  a  long  distance,  must  be  generated  in  a  long  coil  of  very  fine 
wire  in  order  to  have  electro-motive  force  sufficient  to  overcome  the  resistance  opposed  to 
it.  In  like  manner  the  electro-magnets  of  the  instrument  n,  in  which  it  is  received  at  the 
far-off  station,  have  the  same  multiplying  characteristics.  The  magneto-electric  current 
exists  only  during  the  motion  of  the  electro-magnet  in  front  of  the  steel  mngnets,  and  this 
motion  must  be  rather  brisk,  or  the  change  of  place  is  slow  and  the  current  feeble  ;  but  the 
current  ceases  with  the  motion.  The  needle,  however,  remains  deflected  from  causes  to 
which  we  have  already  referred,  and  if  the  hand  is  gently  raised,  so  that  the  coils  return 
slowly  to  their  normal  position,  the  needle  will  remain  deflected  ;  but,  if  the  hand  is  so 
removed  that  the  coils  return  quickly  from  the  region  of  greatest  to  one  of  lesser  magnetic 
force,  a  reverse  current  of  lesser  force  than  the  original  is  generated,  which  releases  the 
needle  from  its  deflected  position  and  restores  it  to  its  normal  place,  ready  for  making 
the  next  signal.  In  a  recent  form  of  this  instrument  Mr.  Henley  has  obviated  the  necessity 
of  moving  the  electro-magnets,  still  retaining  the  same  fundamental  principles.  He  uses  a 
set  of  large  U-shapcd  permanent  magnets,  and  places  the  electro-magnet  in  the  space  be- 
tween the  branches  of  the  permanent  magnet,  and  so  that  the  four  poles  of  the  two  mug 


ELECTRO-TELEGRAPHY.  507 

net.-,  the  permanent  and  the  electro,  shall  be  flush  with  each  other,  or  in  the  same  plane.  A 
couple  of  iron  armatures  are  mounted  on  a  disc  in  front  of  the  magnets.  The  disc  has  a 
motion  on  a  centre ;  the  armatures  are  curved  or  crescent-shaped.  Their  form  is  so  ad- 
justed to  the  relative  positions  of  the  poles  of  tlie  respective  magnets,  that,  in  their  normal 
or  ordinary  position,  one  crescent  connects  the  N.  pole  of  the  magnet  with  one,  say  the 
2ipper  pole  of  the  electro-magnet,  and  the  other  crescent  connects  tlie  S.  pole  of  the  per- 
manent magnet  with  the  lower  pole  of  tlie  electro-magnet.  On  pressing  a  key  the  disc 
moves,  and  the  armatures  so  change  in  position  that  the  N.  pole  of  the  magnet  is  connected 
with  the  lower,  and  the  S.  pole  with  the  upper  poles  of  the  electro-magnet.  By  this 
arrangement  the  polarity  of  the  electro-magnet  is  reversed  at  pleasure,  and  in  its  transition 
from  being  a  magnet  with  poles  in  one  direction,  to  becoming  a  magnet  with  poles  in  the 
reverse  direction,  an  electric  current  is  generated  in  the  wire  with  which  it  is  wound,  and 
the  direction  of  the  current  is  this  way  or  that,  according  as  the  transition  is  from  this  direc- 
tion of  polarity  to  that.  This  form  of  magneto-electric  machine  allows  of  larger  electro- 
magnetic coils  being  used,  and  gives  the  manipulator  comparatively  very  Uttle  weight  to 
move  in  signalling. 

We  have  shown  how  an  electric  current  generates  magnetism,  and  how  magnetism  gen- 
erates another  electric  current ;  it  would  follow  logically  that  one  electric  current  should 
therefore  generate  another  electric  current ;  for  the  magnetism  produced  by  a  current  circu- 
lating in  one  wire,  must  have  a!l  the  properties  of  magnetism,  and  among  them  that  of  pro- 
ducing another  current  in  another  wire  ;  aitS  so  it  is.  A  few  convolutions  of  a  large-sized 
wire  are  coiled  round  an  iron  rod  ;  and  outside  the  larger  wire  is  a  very  great  length  of 
finer  wire.  The  current  from  the  battery  is  called  the  primary  current  in  this  arrange- 
ment ;  and  the  moment  it  begins  to  circulate  in  the  large  wire,  it  magnetizes  the  iron  and 
generates  a  current,  culled  secondar;/,  in  the  fine  wire,  which  is  able  to  penetrate  to  a  very 
great  distance.  When  the  primary  current  ceases,  magnetization  ceases,  the  lines  of  mag- 
netic force  disappear,  and  a  reverse  secondary  current  is  produced.  This  was  the  method 
proposed  for  obtaining  the  secondary  current  for  traversing  the  Atlantic  Ocean  from  Ireland 
to  Newfoundland.  Tiie  large  wire  is  not  necessarily  first  coiled  on ;  in  the  coils  for  the 
Transatlantic  telegraph  it  was  coiled  outside.  Nor  is  the  presence  of  iron  essential  to  ob- 
taining secondary  currents. 

It  will  have  been  noticed  in  all  the  arrangements  which  have  hitherto  been  described, 
that  the  signals  are  produced  by  motions, — that  the  electric  current,  on  reaching  the  far 
station,  is  multiplied  by  being  directed  through  many  convolutions  of  wire,  and  is  made  to 
act  upon  either  a  piece  of  soft  iron  or  a  piece  of  magnetized  steel,  and  to  move  them,  the 
motion  being  turned  to  account  directly,  or  by  the  intervention  of  mechanism.  We  have 
yet  another  property  of  electricity,  that  has  been  very  successfully  applied  to  the  produc- 
tion of  telegraphic  signals  by  Mr.  Bain,  in  his  electro-chemical  telegraph.  If  a  current  of 
electricity  is  led  into  a  compound  fluid  body,  say  into  water,  by  one  wire  and  out  of  it  by 
another  wire,  the  body  is  decomposed  into  its  constituent  elements,  one  of  which,  the  oxy- 
gen in  the  case  in  question,  makes  its  appearance  at  one  wire,  and  the  other,  the  hydrogen, 
makes  its  appearance  at  the  other  wire.     The  same 

holds  good  with  bodies  of  a  more  complex  charac-  278 

ter  in  solution  in  water.  The  compound  selected 
by  Mr.  Bain  is  cyanide  of  potassium.  With  a  so- 
lution of  this,  he  saturates  a  long  ribbon  of  paper, 
similar  to  that  employed  in  Morse's  telegraph.  He 
causes  the  paper  b  {Jiff.  278)  to  pass  over  a  drum 
of  brass  R,  between  the  metal  of  n  and  an  iron 
point  or  stylus  p.  The  electric  current  enters  the 
apparatus  by  the  point  p,  passes  through  the  solu- 
tion of  cyanide  of  potassium,  with  which  the  paper 
B  is  saturated,  and  out  by  tlie  spring  p',  which  is  in 
metallic  contact  with  the  drum  k.  Decomposition 
takes  place,  and  the  well-known  cyanide  of  iron  (Prussian  blue)  is  formed  at  the  point  of 
contact  of  the  iron  stylus  p  with  the  paper,  the  iron  of  the  compound  being  supi)lie(l  by 
the  stylus  itself.  The  paper  is  carried  on  by  ordinary  mechanism  ;  and  a  dot  and  dash 
alphabet  is  formed,  according  to  the  duration  of  contacts  at  the  sending  station.  There  is 
a  single  wire  and  a  double  wire  code  ;  and  the  signals  appear  as  deep  blue  marks  upon  the 
paper.  Supplies  of  paper  saturated  with  the  solution  are  kept  in  reserve.  This  is  unques- 
tionably a  telegraph  of  extreme  simplicity.     It  has  been  employed  with  much  success. 

Mr.  Whitehouse  prepared  for  the  Atlantic  Telegraph  a  system  in  which  motion  anil 
chemical  action  each  play  their  part.  The  .secondary  currents  that  he  em])loyed  were  not 
able  to  produce  the  chemical  decomposition  that  he  reipiires  for  his  signals.  He  therefore 
received  them  in  a  very  sensitive  relay,  either  an  electro-magnet  or  a  multiplier.  The  relay 
was  a  contact-maker,  and  connected  the  necessary  number  of  local  batteries  with  the  print- 


508 


ELECTRO-TELEGRAPHY. 


ill"  apparatus,  which  consists  of  a  ribbon  of  paper,  saturated  with  a  thenueul  suUitioii,  and 
passing  between  a  drum  and  a  steel  point. 

We  should  exceed  our  limits,  were  we  to  attempt  the  description  of  some  of  tlie  many 
other  forms  that  have  been  proposed.  The  above  are  good  illustrations  of  the  leading  prin- 
ciples, and  are  all  in  successful  use.  Some  telegraphs  will  print  in  ordinary  characters ; 
this  result  is  only  attained  by  much  complexity ;  and  its  value  is  more  than  questionable,  it 
being  as  ejii^y  to  learn  a  new  code  as  a  new  alphabet ;  and  telegraph  clerks  read  their  sig- 
nals as  readily  as  they  read  ordinary  writing  or  printing,  and  tliey  acquire  their  knowledge 
in  a  very  short  time.  Hence,  probably,  it  is  that  telegraphs  to  print  in  ordinary  characters 
arc  but  little  known  in  real  practice  ;  nevertheless,  some  very  promising  instruments  of  the 
class  have  been  produced,  by  House,  and  especially  one  more  recently  by  Hughes,  both  of 
tlie  I'nitcd  States.  The  following  table  has  been  drawn  out  as  an  illustration  of  the  codes 
of  some  of  the  chief  instruments  that  have  been  the  subject  of  this  article.  It  shows  the 
number  and  nature  of  the  signals  (deflections,  dots,  dashes)  for  producing  the  name  of  the 
great  discoverer  of  electro-magnetism,  which  is  the  foundation  of  electro-telegraphy.  The 
figures  on  the  right  arc  the  number  of  marks  or  signs  in  printing,  and  in  each  kind  of  tele- 
graph. 


1.  Single    ^    Cooke    f        /// 
and       '1       ^" 

Wheat 

2.  Double   I     stone. 


/// 


3.  Single 

-1.  Double 

5.  Morse  - 

6.  Single    ^ 

7.  Double 


Henley 


Mil 


Bain      -^1    _ 


W 


V 


/    III  Hill  nil 


IIW  l\\\l 


Ml 


Mil 


\ll 


W 


// 


\/ 
\/ 


20 

13 
'l6 
19 
15 
17 

h6 


The  Rheo-ehctro-static  system  of  telegraphy  was  fir.st  described  by  M.  Botto,  in  1848. 
It  is  applicable  to  some  but  not  to  all  forms  of  telegraph.  It  has  been  applied  on  the  South- 
Eastern  Railway  to  the  signal-bells,  {fcj.  268,)  for  the  purpose  of  reducing  the  amount  of 
battery  power  required  under  otlier  circumstances  to  be  maintained.  The  wire,  by  which  a 
pair  of  IdcIIs  are  connected,  is  in  its  normal  state  in  permanent  connection  with  the  similar 
pole,  say  the  positive,  of  batteries  of  equal  power  at  the  respective  stations,  so  that  two 
currents  of  equal  power  are  tjpposed  to  and  balanced  against  each  other.  Under  these  cir- 
cimistances,  the  wire  is  in  a  null,  or  rheo-clectro-static  state;  neither  current  circulates.  If 
the  connection  of  one  of  the  lialferies  is  reversed,  so  that  its  negative  pole  is  presented  to 
the  wire,  tl)en  the  currents  of  iioth  batteries  are  in  the  same  direction,  and  they  circulate  as 
one  current,  equal  in  value  to  the  combined  force  of  the  two  liattcrics.  The  application  is 
obvious  ;  that,  whereas,  under  the  ordinary  system,  a  v-hoh  battery,  of  force  sufficient  to 
traverse  the  distance  and  do  efTective  work,  must  be  at  each  station,  under  this  S3'stem  only 
Art//" such  battery  is  necessary  at  each  station,  for  producing  the  same  effective  work.  Also, 
if  a  little  more  battery  power  is  pl.iced  at  each  station  than  is  necessary  for  the  actual  work 
required,  signals  of  higher  power  are  obtained  under  common  circumstances ;  and  also  the 
equilibrium  of  the  two  opposed  currents  may  be  disturbed  at  any  place  between  the  two 
stations,  and  signals  may  be  made  by  merely  making  a  connection  between  the  line  wire 
ami  the  earth  ;  because  the  negative  pole  at  each  station  is  fitted  up  in  permanent  connec- 
tion with  the  earth ;  and,  as  the  positive  poles  are  in  like  connection  with  the  lino  wire, 
each  battery  current  is  made  to  circulate  through  its  own  signal-bell  every  time  the  earth 
and  line  wire  are  placed  in  coimection.  By  this  means  the  guard  of  a  train  can  make  sig- 
nals of  distress  to  the  nearest  station  without  the  aid  of  portable  apparatus.  Considerable 
care  is  required  to  obtain  good  comnnmication  with  the  earth  on  the  open  railway  for  mak- 
ing distress  signals,  f)r  otherwise  the  discharge  is  imperfect,  and  no  signal  is  made.  P'ish- 
jointed  rails  are  very  valuable  for  this  purpose  ;  in  their  absence,  especially  at  embank- 
ments, metal  must  be  buried  for  the  pm-pose  at  intei-vals  in  the  moist  earth,  and  a  wire 
attached  for  use.     Contact  springs  on  tliC  telegraph  poles  are  proposed. 


ELECTRO-TELEGRAPHY. 


509 


o 


Telegraph  wires  are  suspended  to  poles  by  insulators  of  earthenware,  glass,  or  porce- 
lain ;  the  material  and  shape  varying  according  to  the  experience  of  the  engineer  and  the 
lengtli  of  line  to  be  insulated.  In  very  short  lengths,  the  battery  power  required  for  over- 
coming tlie  resistance  is  not  great ;  it  will  therefore  not  overcome  the  resistance  of  an  insu- 
lator of  moderate  quality,  and  escape  to  the 
pole  and  thence  to  the  earth  ;  but  the  bat-  - '  ^ 

tery  power  required  to  overcome  the  resist- 
ance of  very  long  lengths  of  wire  is  equally 
able  to  overcome  the  resistances  presented 
by  inferior  insulators,  and  to  escape  in  con- 
siderable quantities  at  every  pole ;  so  that 
the  force  which  reaches  the  far  station  would 
not  be  equal  to  its  work.  It  is  for  these  long 
lines  that  the  greatest  ingenuity  has  been 
expended  in  constructing  insulators.  Fine 
porcelain  is  most  in  favor,  from  its  present- 
ing a  very  smooth  surface,  and  being  less 
hygrometric  than  glass  ;  and  it  is  distorted 
into  most  mysterious-looking  shapes  in  order 
to  present  as  great  a  distance,  and  one  as 
much  sheltered  as  possible,  between  the  part 
with  which  the  line  wire  is  in  contact,  and 
the  part  that  is  in  contact  with  the  pole. 

For  subterranean  and  submarine  wires 
still  greater  care  is  necessary,  because  they 
are  in  the  very  bosom  of  the  earth  or  sea, 
to  which  the  current  will  escape,  when  and 
where  it  can,  in  order  to  complete  the  dis- 
charge. Fig.  279  represents  the  cable  that 
has  been  lying  in  the  British  Channel  be- 
tween Dover  and  Calais,  since  September, 
1S5I.  It  contains  four  No.  16  copper  wires ; 
each  wire  is  doubly  covered  with  gutta  per- 
cha.  The  four  wires  are  then  twisted  into  a 
rope,  and  the  rope  is  thickly  covered,  first 
with  hempen  yarn,  tarred,  and  finally  with  a 
jacket  of  ten  No.  1  iron  wires.  The  cable 
is  shown  in  perspective  and  in  section.  Fiff. 
280  shows  the  perspective  and  section  of  the 
Irish,  a  single-wire  cable.  It  consists  of  a 
single  central  conductor,  of  one  No.  16  cop- 
per wire,  doubly  covered  with  gutta  percha, 
then  with  hempen  yarn  as  before ;  and  final- 
ly with  a  protecting  jacket  of  ten  No.  8  iron 
wires.  The  Calais  cable  weighs  7  tons  per 
mile ;  the  Irish,  2  tons  per  mile.  The  At- 
lantic Telegraph  cable,  of  which  nearly  3,000 
miles  were  prepared,  is  in  section,  just  the 
size  of  a  silver  threepenny  piece.  It  is  a 
single-wire  caljle  ;  the  wire  was  a  strand  of 
seven  No.  22  copper  wires,  trebly  covered 
with  gutta  percha,  then  with  yarn,  and  pro- 
tected with  eighteen  strands  of  seven  wires 
each,  of  No.  22  iron  wire.  It  wejghs  19 
cwt.  to  the  mile.  This  cable  is  lost.  The 
iron  jacket  is  in  disrepute  now  for  deep-sea  cables.     Ilemi)  is  preferred. 

Telegraph  signals  pass  with  far  less  rapidity  through  buried  and  through  submnrine 
wires,  than  along  the  ancient  aerial  wires.  The  slow  travellings  mentioned  above,  were 
through  wires  of  this  kind.  We  must  refer  to  treatises  on  Electricity  for  full  details  of  the 
conditions  presented  by  a  telegraph  cable.  In  practice  it  is  found,  that  on  first  sending  a 
signal  into  a  submerged  wire,  the  electricity  is  delayed  on  its  road,  in  order  to  produce  a 
certain  electrical  condition  upon  the  surf\ice  of  the  gutta  percha  that  is  in  immediate  con- 
tact with  the  cnmlucting  wire.  Nor  is  this  all  ;  before  a  set-oiid  distinctive  signal  can  be 
sent,  it  is  necessary  that  the  condition  produced  by  the  first  signal  shall  be  destroyed  ;  and 
this  is  an  operation  requiring  even  more  time  than  was  consumed  in  the  mere  act  of  |)ro- 
ducing  it.  These  two  classes  of  retardation,  especially  the  latter,  were  largely  manifested 
in  the  Atlantic  cable,  and  have  called  forth  all  the  ingenuity  of  electricians,  in  order  to 
mitigate  or  to  modify  them. — C.  V.  W. 


510  EMAIL  OMBRANT. 

EMAIL  OMBRANT.  A  process  which  consists  in  flooding  colored  but  transparent  glaives 
over  designs  stamped  in  the  body  of  earthenware  or  porcelain.  A  plane  surface  is  thus 
produced,  in  wliich  the  cavities  of  the  stamped  design  appear  as  shadows  of  various  depths, 
the  parts  in  highest  relief  coming  nearest  the  surface  of  the  glaze,  and  thus  having  the 
effect  of  the  lights  of  the  picture.  This  process  was  introduced  by  the  Baron  A.  De  Trem- 
blay,  of  Rubellcs,  near  Melun. 

EMBOSSING  WOOD.  A  process  which  may  be  regarded  cither  as  carving  or  emboss- 
ing wood,  is  that  patented  by  Messrs.  A.  S.  Braithwaite  &  Co. 

Oak,  mahogany,  rosewood,  horse-chestnut,  or  other  wood,  is  steeped  in  water  for  about 
two  hours ;  and  the  cast-iron  mould  containing  the  device  is  heated  to  redness,  or  sometimes 
to  a  white  heat,  and  applied  against  the  wood,  either  by  a  handle,  as  a  branding-iron,  by  a 
lever  press,  or  by  a  screw  press,  according  to  circumstances ;  the  moulds  are  made  by  the 
iron-founder  from  plaster  casts  of  the  original  models  or  carvings. 

Had  not  the  wood  been  saturated  with  water,  it  would  be  ignited,  but  until  the  moisture 
is  evaporated,  it  is  only  charred  ;  it  gives  oft"  volumes  of  smoke,  but  no  flame.  After  a 
short  time  the  iron  is  returned  to  the  furnace  to  be  reheated,  the  blackened  wood  is  well 
rubbed  with  a  hard  brush  to  remove  the  charcoal  powder,  which  being  a  bad  conductor  of 
heat,  saves  the  wood  from  material  discoloration  ;  and  before  the  reapplication  of  the  heated 
iron,  the  wood  is  again  soaked  in  water,  but  for  a  shorter  time,  as  it  now  absorbs  moisture 
with  more  facility. 

The  rotation  of  burning,  brushing,  and  wetting,  is  repeated  ten  or  twenty  times,  or  up- 
wards, until  in  fact  the  wood  fills  every  cavity  in  the  mould,  the  process  being  materially 
influenced  by  the  character  and  condition  of  the  wood  itself,  and  the  degrees  to  which  heat 
and  moisture  are  applied.  The  water  so  far  checks  the  destruction  of  the  wood,  or  even  its 
change  of  any  kind,  that  the  burned  surface,  simply  cleaned  by  brushing,  is  often  employed, 
as  it  may  be  left  either  of  a  very  pale  or  deep  brown,  according  to  the  tone  of  color  re- 
quired, so  as  to  match  old  carvings  of  any  age  ;  or  a  very  little  scraping  removes  the  dis- 
colored surface.  Perforated  carvings  are  burned  upon  thick  blocks  of  wood,  and  cut  off 
with  the  circular  saw. 

EMERALD.  Fine  emeralds  are  found  in  a  vein  of  dolomite,  which  traverses  the  horn- 
blende slate  at  Muzo,  north  of  Snnta  Fe  de  Bogota.  A  perfect  hexagonal  crystal  from  this 
locality,  two  inches  long,  is  in  the  cabinet  of  the  Duke  of  Devonshire  ;  it  measures  across 
its  three  diameters  2^  in.,  2V5  in.,  Ig  in.,  and  weighs  8  oz.  18  dwts. : — owing  to  flaws,  it  is 
but  partially  fit  for  jewellery.  A  more  splendid  specimen,  though  somewhat  smaller,  weigh- 
ing but  6  oz.,  is  in  the  possession  of  Mr.  Hope  ;  it  cost  £5C)0.  Emeralds  of  less  beauty,  but 
much  larger,  occur  in  Siberia.  One  specimen  in  the  royal  collection  measures  14^  inches 
long  and  12  broad,  and  weighs  16f  lbs.  troy  ;  another  is  7  in-ches  long  and  4  inches  broad, 
and  weighs  6  lbs.  troy. — Dana. 

The  emerald  is  generally  believed  to  derive  its  color  from  the  presence  of  a  minute 
quantity  of  oxide  of  chrome,  the  beryl  from  oxide  of  iron. 

This  mineral  has  been  recently  examined  with  great  care  by  M.  Lewy,  from  whose  com- 
munication to  the  Academy  of  Sciences  we  abstract  the  following  : — 

"  M.  Lewy  visited  a  mine  called  Muzo,  in  New  Granada,  Mexico,  and  obtained  some  fine 
specimens  of  emeralds,  and  of  the  rocks  in  which  those  precious  stones  are  found.  He 
observed  that  the  largest  and  finest  emeralds  could  be  reduced  to  powder  by  a  slight  squeez- 
ing or  rubbing  between  the  fingers  when  first  obtained,  Ijut  that  they  acquired  hardness  after 
a  certain  time  and  repose.  It  has  been  commonly  stated  that  the  coloring  matter  of  the 
emerald  is  chrome,  but  M.  Lewy  attributes  it  to  an  organic  coloring  matter,  analogous  to 
chlorophifle.  He  states  that  the  emerald  exposed  to  heat  loses  all  color  ;  whereas  minerals 
colored  by  chrome  do  not  lose  their  green  color  by  ignition. 

The  green  color  of  the  emerald  is  darkest  in  those  specimens  which  furnish  to  analysis 
most  organic  matter  :  it  is  completely  destroyed  by  heat,  becoming  white  and  opaque. 

ENAMELS.  The  following  was  the  process  adopted  l)y  Henry  Bone,  R.  A.,  and  hrs 
son,  the  late  Henry  Pierce  Bone,  who  have  produced  the  largest  enamels  ever  painted  ;  and 
))eyond  the  time  and  consequent  expense  there  appears  no  practical  limit  to  the  size  of 
enamel  paintings. 

Prepnrinr!  the  Plate. — For  small  plates,  (up  to  two  inches  long,)  pvre  gold  is  the  best 
material.  Silver  (quite  pure)  is  also  used,  but  is  apt  to  get  a  disagreeable  yellow  color  at 
the  edges  by  repeated  firings.  For  larger  sizes,  copper  is  used.  The  copper  should  be 
annealed  until  quite  free  from  spring,  and  then  cleaned  with  dilute  sulphuric  acid,  (one  part 
acid,  four  water,)  and  shaped  in  a  wooden  mould,  afterwards  used  in  making  the  plate  so  as 
to  produce  a  convex  surface  varying  according  to  the  size  of  the  plate,  taking  care  that  the 
shaping  does  not  reproduce  the  spring  in  the  copper,  in  which  case  the  process  must  be  re- 
peated. If  the  plate  is  not  raised  in  the  centre,  in  the  course  of  repeated  firings  the  cor- 
ners will  rise  irregularly,  producing  imdulations  over  the  plate,  perfect  flatness  being  next 
to  impossil)le  for  large  pictures.  The  copper  is  then  laid  face  downwards  on  the  convex 
wooden  mould  used  for  sh.iping,  and  enamel  ground  fine  with  water  is  spread  over  it  with 


ENGRAVING.  511 

a  small  bone  spoon  ;  when  covered,  a  fine  cloth  doubled  is  pressed  gently  on  it  to  absorb 
the  water,  and  then  it  is  smoothed  with  a  steel  spatula.  This  forms  the  back  of  the  plate, 
and  when  fired  this  part  is  finished.  The  copper  is  now  reversed  on  a  convex  board  the 
exact  counterpart  of  the  other,  and  covered  with  white  enamel  ground  fine  in  the  same  way 
as  above.  The  plate  is  now  ready  for  firing,  and  after  it  has  been  fired  and  cooled,  the  sur- 
face must  be  ground  smooth  with  a  flat  piece  of  flint  or  other  hard  substance,  with  silvpr 
sand  and  water.  It  must  next  be  covered  with  a  softer  and  more  transparent  kind  of 
enamel  called  flux,  ground  and  spread  on  in  the  same  way  as  the  first  enamel,  but  this  time 
only  on  the  face  of  the  plate.  This  is  fired  as  before,  and  when  cool  the  surface  must  be 
again  ground  smooth,  and  when  glazed  in  the  furnace  the  plate  is  finished.  For  the  first 
coat  a  white  solid  enamel  is  used  to  prevent  the  green  color  from  the  oxidized  copper  show- 
ing through  ;  the  second  coat  is  a  softer  enamel,  to  enable  the  colors  used  to  melt  with  less 
heat. 

Firing. — The  plate  is  placed  on  a  planche  of  firestone,  or  well-baked  Stourbridge  clay, 
supported  on  a  bed  of  whiting,  thoroughly  dried  iu  the  furnace,  the  exact  shape  of  the  plate 
as  originally  made,  which  must  be  used  in  all  subsequent  firings.  After  the  whiting  is 
formed  in  the  shape  of  the  plate,  it  should  be  notched  with  a  flat  knife  diagonally  across, 
as  in  the  accompanying  diagram.  The  use  of  this  is  to 
produce  an  effect  of  diagonal  bracing  while  the  plate  cools,  287 

and  experience  has  shown  that  it  tends  considerably  to  keep 
the  plate  in  its  original  .shape.  When  the  plate  is  small, 
(up  to  three  inches  in  length,)  it  may  bo  annealed  for  pass- 
ing into  the  hot  muffle  as  follows : — The  planche  bearing 
the  plate  may  be  placed  on  another  planche  heated  in  the 
muffle  and  placed  in  the  front  of  the  muffle  for  a  few  min- 
utes, until  the  steam  of  the  plate  or  the  oil  of  the  picture 

shall  have  evaporated ;  it  may  then  be  put  in  the  mouth  of     

the  muffle  and  gradually  inserted  to  the  hottest  part.    After  ^,  pianrho 

firing,  it  should  be  placed  on  another   hot  planche  and  b  Bed  of  whiting. 

allowed  to  cool  gradually.  Large  pictures  require  a  differ- 
ent arrangement  of  the  furnace.  Over  the  muffle  there  should  be  a  fixed  iron  annealing- 
box,  with  an  iron  shelf  and  door.  The  bottom  should  be  of  cast  iron  about  one  inch  thick. 
This  should  be  so  arranged  that  when  the  muffle  attains  a  white  heat,  the  bottom  of  the 
annealing-box  should  be  of  a  brightish  red  at  the  back,  and  a  dull  blood-red  in  front. 
Large  pictures  should  be  placed  on  the  bottom  of  the  box  before  the  furnace  is  lit,  and  the 
larger  the  size  of  the  picture,  the  slower  should  the  furnace  be  brought  to  its  full  heat,  so 
as  to  allow  five  or  six  hours  for  the  largest  size,  and  two  or  three  for  smaller  plates.  When 
fired,  the  picture  should  be  returued  to  the  shelf  of  the  annealing-box,  and  left  there  till 
quite  eold^  for  which  purpose  large  plates  require  at  least  twelve  hours.  The  colors  used 
are  mostly  the  same  as  those  prepared  for  jewellers  and  glass-painters. 

ENCAUSTIC  PAINTING.  A  mode  of  painting  with  heated  or  burnt  wax,  which  was 
practised  by  the  ancients.  The  wax,  when  melted,  was  mixed  with  as  much  color,  finely 
powdered,  as  it  could  imbibe,  and  then  the  mass  was  spread  on  the  wall  with  a  hot  spatula. 
When  it  became  cold  the  designer  cut  the  lines  with  a  cold  pointed  tool,  and  other  colors 
were  applied  and  melted  into  the  former.  Many  modifications  of  the  process  have  been 
employed.  Amongst  the  moderns,  the  term  has  been  improperly  given  to  some  cements, 
which  have  nothing  of  an  encaustic  character  about  them. 

ENGRAVING.  Engraving  on  metal  plates  may  be  cla.s.sed  under  the  following  heads : 
Elckinfiy  line,  mezzotinto,  chalk,  stipple,  and  aquatint.  Before  describing  the  processes 
of  working  these  respective  kinds,  a  notice  of  the  instruments  used  by  the  engraver  is 
necessary.     These,  with  some  modifications,  are  employed  in  all  the  styles. 

The  etching -point,  or  needle,  is  a  stout  piece  of  steel  wire  inserted  into  a  handle  ;  two 
or  three,  varying  in  thickness,  are  requisite,  and  they  shoidd  be  freciuently  and  carcM'nlly 
sharpened.  This  is  best  done  by  turning  the  needle  round  in  the  fingers  while  rubl)ing  it 
on  a  hone,  and  afterwards  on  a  leather  strop  prepared  with  putty  powder,  or  on  an  ordinary 
razor-strop,  to  take  off  any  roughness,  and  to  make  it  ptrfeetly  round. 

The  dn/-poi?it  is  a  similar  instrument,  used  for  delicate  lines  :  it  must  be  sharpened  on 
the  hone  till  a  fine  conical  point  is  obtained. 

The  graver,  or  burin,  is  the  principal  instrument  employed  in  engraving :  several  are 
required,  differing  from  each  other  in  form,  from  the  extreme  lozenge  .shape  to  the  sijnarc ; 
the  former  being  used  for  cutting  fine  lines,  the  latter  for  l)r()ad  :  the  giaver  fits  into  a  handle 
about  five  inches  and  a  half  long,  and  it  shotild  be  well  tempered  before  using — an  opera- 
tion requiring  great  care.  The  angle  at  the  meeting  of  the  two  lower  sides  is  called  the 
bdly,  and  the  breadth  of  the  end,  the  fare.  To  sharpen  the  former,  lay  one  of  the  flat 
sides  of  the  graver  on  the  oilstone,  keeping  the  right  arm  toleralily  clo.'^e  to  the  sidi',  and 
rub  ifc  firmly  ;  next  rub  the  other  in  the  same  way  :  the  faee  is  .sharpened  by  holding  it 
firmly  in   the  hand,  with  the  belly  upwards,  iu  a  slanting  direction  ;    rub  the  end  rather 


512  ENGRAVING. 

gently  on  the  stone,  at  an  angle  of  about  forty-five  degrees,  taking  care  to  carry  it  evenly 
alon"-  until  it  acquires  a  very  sharp  point :  this  being  done,  hold  the  graver  a  little  more 
upright  to  squaie  the  point,  which  a  very  few  rubbings  will  eft'ect.  The  graver  lor  line 
work  must  be  slightly  turned  up,  to  enable  the  engraver  to  run  it  along  the  plate  ;  other- 
wise the  first  indentation  he  makes  on  the  metal  would  cause  his  instrument  to  beconie 
fixed  :   the  graver  for  stipple  should  be  slightly  turned  down,  to  make  dots  only. 

The  scraper,  which  should  have  three  fiutcd  sides,  is  used  for  taking  off  the  burr  left  by 
the  action  of  the  needles  on  the  metal. 

The  burnisher  is  employed  to  soften  lines  that  have  been  bltfen  in,  or  engraved  too  dark, 
and  to  polish  the  plate,  or  get  rid  of  any  scratches,  it  may  accidentally  have  received. 

Tlie  dabber  used  to  lay  the  etc/iiuff-f/round  evenly,  is  made  by  enclosing  a  small  quantity 
of  fine  cotton  wool  very  tightly  in  a  piece  of  silk,  the  threads  of  which  should  be,  as  much 
as  possible,  of  uniform  thickness. 

There  are  a  few  other  materials  which  an  engraver  should  have  at  hand,  but  they  are 
not  of  sufficient  importance  to  be  mentioned  here ;  we  may,  however,  point  out  what  is 
technically  called  a  briJijc,  which  is  nothing  more  than  a  thin  board  for  the  hand  to  rest  on  ; 
it  should  be  smoothly  planed,  and  of  a  length  and  breadth  in  proportion  to  the  size  of  the 
plate  ;  at  each  end  a  small  piece  of  wood  should  be  fastened  to  raise  it  above  the  plate  when 
covered  with  wax.  A  blind,  made  of  tissue  paper  stretched  upon  a  frame,  ought  to  be 
placed  between  tiie  plate  and  the  light,  to  enable  the  engraver  to  see  his  work  on  the  metal 
with  greater  facility  and  clearness. 

Ill  describing  the  processes  of  engraving  the  various  styles  enumerated  above,  little 
more  than  a  general  outline  of  each  method  can  be  given,  yet  sufficient,  it  may  be  pre- 
sumed, to  show  the  nature  of  the  operation  :  to  narrate  all  the  details  that  might  be  in- 
cluded in  the  subject  would  supply  matter  enough  for  a  small  volume. 

Etchinc)  may  be  classed  under  two  heads :  that  which  is  made  the  initiatory  process  in 
line  engraving,  and  that  which  is  known  as  pai7itcr''s  etching.  The  latter  was  practised  to 
some  extent  by  very  many  of  the  old  painters,  particularly  those  of  the  Dutch  school ;  and 
it  has  also  recently  come  into  fashion  with  many  of  the  artists  of  our  own  day,  but  more 
for  amusement,  however,  than  for  any  other  purpose;  in  both  cases  the  method  of  proceed- 
ing is  alike.  Etching  is  the  result  of  a  chemical  process  resulting  in  corrosion  of  the  metal 
on  which  the  design  has  been  laid  down,  or  transferred,  in  the  following  manner : — The 
plate  must  first  be  covered  with  a  substance  already  spoken  of  as  ctc/iinf/-ffround,  which  may 
be  purchased  of  most  of  the  principal  artists'  colormen,  but  many  engravers  make  their 
own  :  the  annexed  receipt  has  been  handed  to  us  by  Mr.  C.  W.  Sharpe,  who  has  engraved 
some  of  the  largest  steel-plates  published  recently,  as  that  which  he  always  uses  : — 

Tarts. 

Black  pitch 1 

White  wax 1 

Burgundy  pitch i 

Asphaltum       .-.- 1 

Gum  mastic    --.-------1 

Melt  the  first  three  ingredients  over  a  slow  fire  in  a  pipkin,  then  add  the  other  two,  finely 
powdered,  stirring  the  whole  together  all  the  time  ;  when  well  mixed,  pour  it  into  warm 
water,  and  make  it  up,  while  warm,  into  balls  ;  if  too  soft,  a  little  less  wax  should  be  used. 
Care  must  be  taken  not  to  let  the  mixture  burn  during  the  process  of  making. 

The  etching-ground  resists  the  action  of  the  a(pia  fortis.  It  should  be  tied  up  in  a 
piece  of  strong  silk,  and  applied  thus,  which  is  called  laying  the  gromid : — Take  the  plate 
firmly  in  a  small  hand-vice  ;  hold  it,  with  the  polished  face  upwards,  over  a  charcoal  fire  that 
it  may  not  get  smoked,  till  it  is  well,  but  not  too  much,  heated  :  rub  the  etching-ground,  in 
the  silk,  over  the  plate  till  it  is  evenly  colored  ;  the  wax,  melting  with  the  heat,  oozes 
through  the  silk.  To  cftect  a  more  equal  distribution  of  the  ground,  take  the  dulbtr  and 
dab  the  plate  gently  all  over,  till  it  appears  of  a  uniform  color ;  continue  the  dabbing  till 
the  ]ilate  begins  to  cool,  but  not  longer.  The  ground  is  then  blackened  by  being  held  over 
the  smoke  of  a  candle,  or  two  or  three  tied  together, — wax  is  far  preferable  to  tallow ; 
keep  the  plate  in  motion,  so  that  every  part  be  made  equally  dark,  and  also  to  avoid  injury, 
bv  burning,  to  the  composition  ;  when  cold,  the  plate  is  ready  to  receive  the  design.  To 
transfer  this,  a  very  correct  outline  of  the  subject  is  made  with  a  black-lead  pencil  on  a 
piece  of  thin  hard  paper :  fasten  the  tracing,  or  drawing,  at  the  top  edge,  with  its  face 
downwards,  on  to  the  etching-ground,  with  a  piece  of  banking-wax,  described  hereafter,  and 
by  passing  it  through  a  printing-press — such  as  is  used  by  plate  printers,  to  whom  it  should 
be  taken — the  drawing  is  transferred  to  the  ground.  The  bridge  being  laid  over  the  plate, 
the' process  of  etching  may  now  be  commenced  ;  the  points,  or  needles,  which  are  used  to 
complete  the  design,  remove  the  ground  from  the  metal  wherever  they  pass,  and  expose  the 
latter  to  the  action  of  the  acid  during  the  process  of  what  is  termed  biting  in.  The  needles 
with  the  most  tapering  points  should  be  used  for  the  skies  and  distances,  changing  them  for 
others  for  the  foreground,  which  generally  requires  broader  and  deeper  lines.     Any  error 


ENGRAVING.  513 

that  has  been  made  may  be  remedied  by  covering  the  part  evenly  with  the  etching-ground 
mollified  by  spirits  of  turpentine,  using  a  camel's-huir  pencil  for  the  purpose ;  and,  when 
dry,  the  lines  may  be  reiitched  througli  it. 

The  next  operation  is  that  of  biting  in,  performed  thus  : — A  wall  or  border  of  bankitig- 
wax  is  put  round  the  edge  of  the  plate  :  this  wax,  called  sometimes  lordcring-wax,  is  made 
by  melting  over  a  slow  fire,  in  a  glazed  pot,  two  parts  of  Burgundy  pitch  and  one  of  bees- 
wax, to  which  is  added,  when  melted,  a  gill  of  sweet  oil ;  when  cold  it  is  quite  hard,  but 
by  immersion  in  warm  water  it  becomes  soft  and  ductile,  and  must  be  applied  in  this  state  ; 
it  will  adhere  to  the  metal  by  being  firmly  pressed  down  with  the  hand  :  the  object  in  thus 
banking  up  the  plate  is  to  prevent  the  escape  of  the  acid  which  is  to  be  applied  ;  but  a  spout 
or  gutter  nmst  be  left  at  one  corner  to  pour  oiF  the  liquid  when  necessary.  Mr.  Fielding — 
to  whose  work  on  the  art  of  engraving  we  are  indebted  for  some  of  the  practical  hints  here 
adduced,  availing  ourselves,  however,  of  the  improvements  introduced  into  modern  prac- 
tice— recommends  the  following  mixture  as  the  best : — "  Procure  some  strong  nitrous  acid, 
and  then  mix,  in  a  wide-mouthed  bottle,  one  part  of  the  acid  with  five  parts  of  water,  add- 
ing to  it  a  small  quantity  of  sal  ammoniac,  in  the  proportion  of  the  size  of  a  hazel-nut  to 
one  pint  of  acid,  when  mixed  for  biting.  The  advantage  of  using  the  sal  ammoniac  is,  that 
it  has  the  peculiar  property  of  causing  the  aqua  fortis  to  bite  more  directly  downwards,  and 
less  laterally,  by  which  means  lines  laid  very  closely  together  are  less  liable  to  run  into  each 
other,  nor  does  the  ground  so  readily  break  up."  When  the  mixture  is  cool — for  the  acid 
becomes  warm  when  first  mixed  with  water — pour  it  on  the  plate,  and  let  it  continue  there 
till  the  more  delicate  lines  are  presumed  to  be  corroded  to  a  sufficient  depth ;  this  will  prob- 
ably be  in  aljout  a  quarter  of  an  hour ;  sweep  off  the  bubbles  as  they  appear  on  the  plate, 
with  a  camel's-hair  pencil,  or  a  feather ;  then  pour  off  the  acid  through  the  gutter  at  the 
corner,  wasli  the  plate  with  warm  water,  and  leave  it  to  dry.  Next,  cover  those  parts  which 
are  sufficiently  bitten  in  with  Brunswick  black,  applying  it  with  a  cameFs-hair  pencil,  and 
leave  it  to  dry ;  again  put  on  the  acid,  and  let  it  remain  twenty  minutes  or  half  an  hour,  to 
give  the  next  degree  of  depth  required ;  and  repeat  this  process  of  stopping  out  and  biting 
in,  until  the  requisite  depths  are  all  attained :  three  bitings  are  generally  enough  for  a 
painte/s  etching.  The  work  is  now  complete,  unless  the  gravei-  is  to  be  used  upon  it,  and 
the  banking-wax  may  be  removed,  by  slightly  warming  the  margin  of  the  plate  ;  and,  finally, 
wash  the  latter  with  a  soft  rag  dipped  in  spirits  of  turpentine,  and  rubbing  it  with  olive  oil. 
If,  when  the  plate  is  cleaned,  the  engraver  finds  that  the  acid  has  acted  as  he  wishes,  he  hiis 
secured  what  is  technically  termed  "  a  good  bite." 

Steel  plates  require  another  method  of  biting  in,  on  account  of  their  extreme  hardness, 
and  liability  to  rust ;  the  mode  just  described  is  applicable  only  to  copper,  the  metal  gen- 
erally used  by  painters  for  their  etchings.     For  steel  plates  mix  together 

Tarts. 

Pyroligncous  acid 1 

Nitric  acid       -- 1 

Water 3 

This  mixture  should  not  be  allowed  to  remain  on  above  a  minute ;  let  it  be  washed  off  at 
once,  and  never  use  the  same  water  twice  ;  the  plate  must  be  set  up  on  its  edge,  and  dried 
as  quickly  as  possible  to  avoid  rust :  the  acid  may  be  strengthened  where  a  stronger  tint  is 
required. 

Rebiting,  a  process  frequently  adopted  to  increase  the  depth  of  tint  where  it  is  required, 
or  to  repair  any  portion  of  a  plate  that  has  been  worn  by  printing  or  accidentally  injured,  is 
thus  performed.  The  plate  must  be  thoroughly  cleaned,  all  traces  of  grease  removed,  by 
washing  it  with  spirits  of  turpentine  and  potass,  and  polished  with  whitening ;  it  is  then, 
when  warmed  over  a  charcoal  fire  or  with  lighted  paper,  ready  for  receiving  the  ground ; 
this  is  laid  by  using  a  dabber  charged  with  etching-ground,  and  carefully  dabbing  the  sur- 
face ;  by  this  means  the  surface  of  the  plate  only  is  covered,  and  the  lines  already  engraved 
are  left  clear  ;  any  part  of  the  plate  that  it  may  not  be  necessary  to  rebite,  must  be  stopped 
out  with  Brunswick  black,  and  then  the  acid  may  be  poured  over  the  whole,  as  in  the  first 
process. 

Etching  on  soft  ground  is  a  style  of  engraving  formerly  much  practised  in  imitation  of 
chalk  or  pencil  drawings ;  since  the  introduction  of  lithography,  however,  it  has  been  en- 
tirely abandoned.  The  soft  ground  is  made  by  adding  one  part  of  hog's  lard  to  three  parts 
of  common  or  hard  etching-ground,  unless  the  weather  be  very  warm,  when  a  smaller  quan- 
tity of  lard  will  suffice  ;  it  should  be  laid  on  and  smoked  in  the  manner  already  described. 
Mr.  Fielding  gives  the  following  method  for  working  on  it : — "  Draw  the  outline  of  your 
subject  faintly  on  a  piece  of  smooth  thin  writing  paper,  which  must  be  at  least  an  inch 
larger  every  way  than  the  plate  ;  then  damp  it,  and  spread  it  cautiously  on  the  ground,  and, 
.turning  the  edges  over,  paste  down  to  the  back  of  the  plate  ;  in  a  few  hours  the  paper  will 
be  dry,  and  stretched  quite  smooth.  Resting  your  hand  on  the  bridge,  take  an  11  or  IIB 
pencil,  and  draw  your  subject  on  the  paper  exactly  as  you  wish  it  to  be,  pressing  strongly 
for  the  darker  touches,  and  more  lightly  ibr  the  delicate  parts,  and,  accordingly  as  you  find 
Vol.  III.— 33 


514  ENGEAVING. 

the  {ground  more  or  less  soft,  which  depends  on  the  heat  of  the  weather  or  the  room  you 
work  in,  use  a  softer  or  harder  pencil,  remembering  always  that  the  softer  the  ground,  the 
softer  the  pencil  "  (should  be).  "  When  the  drawing  is  finished,  lift  up  the  paper  carefully 
from  the  plate,  and  wherever  you  have  touched  with  the  pencil,  the  ground  will  stick  to  the 
paper,  leaving  the  copper  more  or  less  exposed.  A  wall  is  then  put  round  the  margin,  the 
plate  bit  in,  and  if  too  feeble,  rebit  in  the  same  way  as  a  common  etching,  using  hard  etch- 
ing-ground for  the  rebite." 

Line  engraving  unquestionably  occupies  the  highest  place  in  the  category  of  the  ai  t ; 
and,  taking  it  as  a  whole,  it  is  the  most  suitable  for  representing  the  various  objects  that 
constitute  a  picture.  The  soft,  pulpy,  and  luminous  character  of  flesh  ;  the  rigid,  hard,  and 
metallic  character  of  armor;  the  graceful  folds  and  undulations  of  draperies,  the  twittering, 
unsteady,  and  luxuriant  foliage  of  trees,  with  the  bright  yet  deep-toned  color  of  skies,  have 
by  this  mode,  when  practised  bj'  the  best  engravers,  been  more  successfully  rendered  than 
by  any  other.  The  process  of  line  engraving  is,  first,  to  etch  the  plate  in  the  manner 
already  described,  and  afterward  to  finish  it  with  the  graver  and  dry-point.  An  engravcr''s 
etching  differs  from  a  painter''s  etching  in  that  every  part  of  the  work  has  an  unfinished  ap- 
pearance, though  many  engravers,  especially  of  landscapes,  carry  their  etchings  so  far  as  to 
make  them  very  effective :  engravers  of  historical  and  other  figure  sulijects,  generally,  do 
little  more  than  etch  the  outlines,  and  the  broad  shadowed  masses,  or  colors,  of  the  draper- 
ies ;  the  flesh  being  entirely  worked  in  with  the  burin,  or  graver:  no  definite  rules  can  be 
laid  down  as  to  the  extent  to  which  the  etching  should  be  advanced  ere  the  work  of  the  tool 
commences,  as  scarcely  two  engravers  adopt  the  same  plan  precisely:  much  must  always 
depend  on  the  nature  of  the  subject.  Neither  would  it  be  possible  to  point  out  in  what  jiar- 
ticular  way  the  graver  should  be  used  in  the  representation  of  any  particular  object — this 
can  only  be  learned  in  the  studio  of  the  master,  or  by  studying  the  works  of  the  best  en- 
gravers: as  a  rule  it  may  be  simply  stated,  that  in  making  the  incision,  or  line,  the  graver 
is  pushed  forward  in  the  direction  required,  and  should  be  held  by  the  handle,  at  an  angle 
very  slightly  inclined  to  the  place  of  the  steel  or  copper  plate :  the  action  of  the  graver  is  to 
cut  the  metal  clean  out. 

Within  the  last  few  years  an  instrument,  called  a  ruling  machine,  has  been  brought  into 
use  for  laying  in  flat  tints  in  skies,  buildings,  and  objects  requiring  straight,  or  slightly 
curved  lines ;  considerable  time  is  saved  to  the  artist  by  its  use,  and  more  even  tints  are 
produced  than  the  most  skilful  handwork,  generally,  is  able  to  eflect ;  but  to  counterbalance 
these  advantages,  freedom  is  frequently  sacrificed,  and  in  printing  a  large  number  of  impres- 
sions, the  machine  work,  unless  very  skilfully  ruled  in,  is  apt  to  wear,  or  to  become  clogged 
with  ink,  sooner  than  that  which  is  graved. 

Mezzotinto  engraving  is  generally  supposed  to  owe  its  origin  to  Colonel  Ludwig  von 
Sicgen,  an  officer  in  the  service  of  the  Landgrave  of  Hesse ;  there  is  extant  a  jjortrait  by 
him,  in  this  style,  of  Amelia,  princess  of  Hesse,  dated  1643.  Von  Siegen  is  said  to  have 
communicated  his  invention  to  Prince  Rupert,  to  whom  many  writers  have  assigned  the 
credit  of  originating  it.  There  are  several  plates  executed  by  the  Prince  still  in  existence. 
It  differs  from  every  other  style  of  engraving,  both  in  execution  and  in  the  appearance  of 
the  impression  which  the  plate  yields:  a  mezzotint  engraving  resembles  a  drawing  done  in 
washes  of  color,  by  means  of  a  camel's-hair  pencil,  rather  than  a  work  executed  with  any 
sharp-pointed  instrument :  but  a  pure  mezzotint  engraving  is  rarely  produced  in  the  prci-ent 
day,  even  for  portraits :  the  advantages  derived  from  combining  line  and  stipple,  of  which 
we  shall  speak  presently,  with  it,  to  express  the  different  kinds  of  texture  in  objects,  have 
been  rendered  so  obvious  as  almost  to  make  them  necessary:  this  combination  is  termed 
the  mired  nfgle.  The  distinguishing  excellencies  of  mezzotint  are  the  rich  depth  of  its 
shadows,  an  exquisite  softness,  and  the  harmonious  blending  of  light  and  shade:  on  the 
other  hand,  its  great  defect  is  the  extreme  coldness  of  the  high  lights,  especially  where  they 
occur  in  broad  masses. 

The  instruments  used  for  this  kind  of  work  arc,  burnishers,  scrapers,  shading  tools,  ron- 
leftes,  and  a  cradle,  or  rocking  tool.  The  burnisher  and  scraper  differ  in  form  from  those 
already  described:  the  roulette  is  used  to  darken  any  part  which  may  have  been  scraped 
away  too  much;  it  ought  to  be  of  different  sizes:  the  cradle  is  of  the  same  form  as  the 
shading  tool,  and  is  used  for  the  purpose  of  laying  ground.s. 

Tlie  operation  of  engraving  in  mezzotint  is  precisely  the  opposite  of  that  adopted  in  all 
otlier  styles :  the  processes  in  the  latter  are  from  light  to  dark,  in  the  former  from  dark  to 
liglit,  and  is  thus  effected  :  A  plate  of  steel  or  copper  is  indented  all  over  its  face  by  the 
cradle,  an  instrument  which  somewhat  resembles  a  chisel  with  a  toothed  or  serrated  edge, 
by  which  a  burr  is  raised  on  every  part  in  such  quantities  that  if  filled  in  with  ink,  and 
printed,  the  impression  would  exhibit  a  uniform  mass  of  deep  l)lack :  this  operation  is  called 
laijitig  the  ground ;  it  is  performed  by  rocking  the  cradle  to  and  fro,  and  the  directions,  or 
leai/s,  as  the  engravers  call  them,  are  determined  by  a  plan,  or  scale,  that  enables  the 
engraver  to  pass  over  the  plate  in  almost  any  number  of  directions  Avithout  repeating  any 
one  of  them.     When  an  outline  of  the  subject  has  been  first  etched  in  the  ordinary  way  be- 


ENGRAVING.  515 

fore  the  ground  is  laid,  the  engraver  proceeds  to  scrape  away,  and  then  burnish  the  highest 
lights,  after  which  the  next  lightest  parts  are  similarly  treated,  and  the  process  is  repeated 
alter  this  manner  till  the  work  is  finished  ;  the  deepest  shades  are  produced  from  the  ground 
that  is  left  untouched.  There  is,  however,  no  style  of  engraving  lor  the  execution  of  which 
it  is  so  difficult  to  lay  down  any  definite  rules,  for  almost  every  engraver  has  his  own  method 
of  working.    . 

Chalk  or  stipple  engraving,  for  the  terms  are  synonymous,  is  extremely  simple.  The 
plate  has  first  to  be  covered  with  tlie  etchhig-ground,  and  the  sulyect  transferred  to  it  in 
the  ordinary  way :  the  outline  is  then  laid  in  by  means  of  small  dots  made  with  the  stipple 
graver ;  all  the  darker  parts  arc  afterwards  etched  in  dots  larger  and  laid  closer  together. 
Tiie  work  is  then  bitten  in  with  the  acid ;  and  the  ground  being  taken  olf,  tlie  stipple 
graver  must  again  be  taken  up  to  complete  the  operation ;  the  light  parts  and  the  dark 
are  respectively  produced  by  small  and  large  dots  laid  in  more  or  less  closely  together. 
Stipple  is  well  adapted  for,  and  is  often  used  in,  the  representation  of  flesh,  when  all  the 
other  parts  of  the  subject  are  executed  in  line :  hence  it  is  very  frequently  employed  in 
portraiture,  and  in  engravings  from  sculpture.  Chalk  engraving  is  simply  the  imitation  of 
drawings  in  chalk,  and  is  executed  like  stipple,  only  that  the  dots  are  made  with  less  regu- 
larity, and  less  uniformity  of  size ;  in  the  present  day,  the  two  terms  are  generally  considered 
as  expressing  the  same  kind  of  work. 

Aquatint  engraving,  which  represents  a  drawing  in  Indian-ink  or  bistre  even  more  than 
does  mezzotint,  has  been  almost  entirely  superseded  by  lithography,  and  still  more  recently 
by  chromo-lithography  ;  and  there  seems  little  probability  that  it  will  ever  come  into  fashion 
again.  This  being  the  case,  and  as  any  detailed  description  of  the  mode  of  working  would, 
to  be  of  any  service,  occupy  a  very  considerable  space,  it  will,  doubtless,  be  deemed  sufficient 
to  give  only  a  brief  outline  of  its  character  and  of  the  mode  of  operation ;  this  we  abbreviate 
from  the  notice  of  Mr.  Fielding,  formerly  one  of  our  most  able  engravers  in  aquatint.  The 
process  consists  in  pouring  over  a  highly-polished  copper  plate  a  liquid  composed  of  resin- 
ous gum  dissolved  in  spirits  of  wine,  which  latter,  evaporating,  leaves  the  resin  spread  all 
over  the  plate  in  minute  grains  that  resist  the  action  of  the  aqua  fortis,  which,  however,  cor- 
rodes the  bare  surface  of  the  copper  that  is  left  between  them :  this  granulated  surface  is 
called  a  ground.  The  ground  having  been  obtained,  the  margin  of  the  plate  should  be  var- 
nished over,  or  stopped  out,  and  when  dry,  the  subject  to  be  aquatinted  must  be  transferred 
to  the  plate,  either  by  tracing  or  drawing  with  a  soft  black-lead  pencil,  which  may  be  used 
on  the  ground  with  nearly  the  same  facility  as  paper  ;  if  the  former  method  be  adopted,  the 
tracing  must  be  carefully  fastened  down  to  the  copper  by  bits  of  wax  along  the  upper  edge. 
A  piece  of  thin  paper,  covered  on  one  side  with  lamp-black  and  sweet  oil,  is  placed  between 
the  tracing  and  the  ground,  with  the  colored  side  downwards,  and  every  line  of  the  subject 
must  be  passed  over  with  the  tracing-point,  using  a  moderate  pressure.  The  tracing  being 
finished  and  the  paper  removed,  a  wall  of  prepared  wax,  about  three-quarters  of  an  inch 
high,  must  be  put  round  the  plate,  with  a  large  spout  at  one  corner,  to  allow  of  the  acid 
running  off. 

The  plate  is  now  ready  for  use ;  and  the  completion  of  the  design  is  commenced  by 
stopping  out  the  highest  lights  on  the  edges  of  clouds,  water,  &c.,  with  a  mixture  of  oxide 
of  bismuth  and  turpentine  varnish,  diluting  it  with  spirits  of  turpentine  till  of  a  proper  con- 
sistence to  work  freely.  Next  pour  on  the  acid,  composed  of  one  part  of  strong  nitrous 
acid  and  five  parts  of  water ;  let  it  remain,  according  to  its  strength,  from  half  a  minute  to  a 
minute,  then  let  it  run  off,  wash  the  plate  two  or  three  times  with  clean  water,  and  dry  it 
carefully  with  a  linen  cloth.  This  process  of  stopping  out  and  biting  in  is  continued  till 
the  work  is  complete  ;  each  time  the  aqua  fortis  is  applied  a  fresh  tint  is  produced,  and  as 
each  part  successively  becomes  dark  enough  it  is  stopped  out ;  in  this  manner  a  plate  is  often 
finished  with  one  ground  bitten  in  ten  or  twelve  times.  We  would  recommend  those  who 
may  desire  to  become  thoroughly  acquainted  with  this  very  interesting  yet  difficult  mode  of 
engraving  to  consult  Fielding's  Art  of  Engraving.   . 

A  few  remarks  explanatory  of  the  method  of  printing  steel  or  copper  plates  seem  to  be 
inseparable  from  the  subject.  The  press  used  for  the  purpose  consists  of  two  cylinders  or 
rollers  of  wood,  supported  in  a  strong  wooden  frame,  and  movable  at  their  axes.  One  of 
these  rollers  is  placed  just  above,  and  the  other  immediately  below,  the  plane  or  table  u))on 
which  the  plate  to  be  printed  is  laid.  The  upper  roller  is  turned  round  by  means  of  cogged 
wheels  fixed  to  its  axis.  The  plate  being  inked  Ijy  a  printer's  inking-roller,  an  o]HMation 
requiring  great  care,  the  paper  which  is  intended  to  receive  the  impression  is  placed  upon 
it,  and  covered  with  two  or  three  folds  of  soft  woollen  stuft"  like  blanketing.  These  are 
moved  along  the  table  to  the  spot  where  the  two  rollers  meet;  and  the  u])|)er  one  being 
turned  by  the  hanillc  fixed  to  the  fly-wheel,  the  plate  passes  through  it,  conveying  the  im- 
pression as  it  moves;  the  print  is  then  taken  olf  the  plate,  which  has  to  undergo  the  sanu> 
process  of  inking  for  the  next  and  every  succeeding  imjuession.  The  proofs  of  an  engraved 
plate  are  always  taken  by  the  most  skilful  worknu'u  in  a  ])rinting  establi.'fhment ;  in  the 
priuci[)al  houses  there  are  generally  erajjloycd  from  two  to  six  men,  aocordingto  the 


516  ENGRAVING. 

amount  of  business  transacted,  whose  duty  it  is  to  print  proof  impressions  only ;  they  are 
called  provers.  A  careful,  steady  workman  is  not  able  to  print  more  than  from  180  to  liOO 
good  ordinary  impressions  from  a  plate,  the  subject  of  which  occupies  about  seven  inches  by 
ten  inches,  even  in  what  is  considered  a  long  day's  work,  that  is,  about  fourteen  houis  ;  the 
prover,  from  the  extreme  care  required  in  inking  the  plate,  and  from  the  extia  time  occu- 
pied in  wiping  it,  and  preparing  the  India-paper,  will  do  from  thirty  to  forty,  according  as 
the  subject  of  the  plate  is  light  or  heavy.  This  difference  in  the  cost  of  production,  taking 
also  into  account  that  the  proofs  are  worked  off  before  the  plate  has  become  worn,  even  in 
the  least  degree,  and  that  very  few  proofs,  comp*ed  with  the  ordinaiy  prints,  are  generally 
struck  oil",  is  the  reason  ^hy  they  are  sold  at  a  price  so  much  greater  than  the  latter. 

Notwithstanding  the  vast  multiplication  of  engravings  witliin  the  last  few  years,  it  ia 
generally  admitted,  by  those  best  acquainted  with  the  present  state  of  the  art,  that  it  is  not 
in  a  healthy  condition.  The  highest  class  of  pictorial  subjects — history,  and  the  highest 
style  of  engraving — line,  have  given  place  to  subjects  of  less  exalted  character,  and  to  a 
mixed  style  of  work,  which,  however  effective  for  its  especial  purpose,  is  not  pure  art.  The 
pictures  by  Sir  E.  Landseer  have  gained  for  cngiavings  of  such  subjects  a  popularity  that 
lias  driven  almost  every  thing  else  out  of  the  field,  and  have  created  a  taste  in  the  public 
which  is  scarcely  a  matter  of  national  congratulation.  We  have  engravers  in  the  country 
capable  of  executing  works  equal  to  whatever  has  been  produced  elsewhere  at  any  time, 
biu  their  talents  are  not  called  into  reciuisition  in  such  a  way  as  to  exhibit  the  art  of  en- 
graving in  its  highest  qualities.  Publishers  are  not  willing  to  risk  their  capital  on  works 
wiiich  the  public  cannot  apiMCciate,  and  hence  their  windows  are  filled  with  prints,  the  sub- 
jects of  which,  however  pleasing  and  popular,  are  not  of  a  kind  to  elevate  the  taste ;  while 
the  conditions  under  which  engravers  generally  are  compelled  to  work,  offer  but  little  in- 
ducement for  the  exercise  of  the  powers  at  their  command.  Engraving  on  copper  is  in  the 
present  day  but  rarely  attempted ;  formerly  nothing  else  was  thought  of;  now  the  demand 
for  engraving  is  so  great  that  copper,  even  aided  by  the  electrotype,  is  insufficient  to  meet 
its  requirements.  In  consequence  of  the  comparatively  small  number  of  imprcs.sions  which 
it  yields,  a  copper-plate  will  seldom  produce  more  than  500  or  600  good  prints ;  we  have 
known  a  steel,  witli  occasionally  retouching,  produce  more  than  S0,000,  when  well  en- 
graved, and  carefully  printed ;  very  much  depends  on  the  printer,  both  with  regard  to  the 
excellence  of  the  impression  and  the  durability  of  the  plate.  The  public  demand  is  for 
prints  both  large  and  cheap,  and  to  obtain  this  result,  the  engraver  is  too  often  obliged  to 
sacrifice  those  qualities  of  his  art  which  under  other  circumstances  his  work  would  exhibit. 
Such  is  the  state  of  engraving  with  us  now.  There  are  few,  even  of  the  best  artists  we 
have,  who  by  their  utmost  efforts  can  earn  an  income  equal  to  that  of  a  tiadesman  in  a 
small  but  respectable  Avay  of  business.  This  is  an  evil  to  be  deplored,  for  it  assists  to 
deteriorate  the  art  by  forcing  the  engraver  to  labor  hard  for  a  maintenance,  instead  of 
placing  him  in  a  position  that  would  enable  him  to  exalt  the  art  and  his  own  reputation  at 
the  same  time. 

A  process  of  depositing  steel  upon  an  engraved  copper-plate  has  recently  been  brought 
over  to  this  country  from  France.  M.  Joubert,  a  French  engraver  long  settled  in  England, 
has  introduced  it  here ;  he  has  infoimed  us  that  a  copper-plate  thus  covered  may  be  made 
to  yield  almost  any  number  of  impressions,  for  as  the  steel  coating  becomes  worn  it  can  be 
entirely  taken  off,  and  a  new  deposit  laid  on  without  injury  to  the  engraving,  and  this  may 
be  done  several  times;  M.  Joubert  has  repeated  the  experiment  with  the  most  satisfactory 
results.  Ue  thus  descril)cs  his  process  in  a  communication  made  to  the  Society  of  Arts, 
and  printed  in  their  journal : — 

"  If  the  two  wires  of  a  galvanic  battery  be  plunged  separately  into  a  solution  of  iron, 
having  ammonia  for  its  basis,  the  wire  of  the  positive  pole  is  immediately  acted  upon,  while 
that  of  the  negative  pole  receives  a  deposit  of  the  metal  of  the  solution — this  is  the  princi- 
ple of  the  process  which  we  have  named  '  acierage.' 

"The  operation  takes  place  m  this  way: — By  placing  at  the  positive  pole  a  plate  or 
sheet  of  iron,  and  immersing  it  in  a  proper  iron  solution,  the  metal  will  be  dissolved  under 
the  action  of  the  battery,  and  will  form  a  hydrochlorate  of  iron,  which,  beiug  combined 
with  the  hydrochlorate  of  ammonia  of  the  solution,  will  become  a  bichloride  of  ammonia 
and  iron ;  ou  a  copper-plate  being  placed  at  the  opposite  i)ole  and  likewise  immersed,  if  the 
solution  be  properly  saturated,  a  deposit  of  iron,  bright  and  perfectly  smooth,  is  thrown 
upon  the  copper-plate,  from  this  principle : — 

"Water  being  composed  of  hydrogen  and  oxygen: 

"Sal  ammoniac  being  composed  of: — 

"  1st.  Hydrochloric  acid,  containing  chlorine  and  hydrogen ; 

"  2d.  Ammonia,  containing  hydrogen,  nitrogen,  and  oxygen  : 

"  The  water  is  decomposed  under  the  galvanic  action,  and  the  oxygen  fixes  itself  on 
the  iron  plate,  forming  an  oxide  of  iron;  the  acid  hydrochloric  of  the  solution,  acting  upon 
this  oxide,  becomes  a  hydrochlorate  of  iron,  whilst  the  hydrogen  precipitates  itself  upon 
the  plate  of  the  negative  pole,  and,  unable  to  combine  with  it,  comes  up  to  the  surface  of 
the  solution  in  bubbles. 


ENGRAVING  ON  WOOD.  517 

"  My  invention  has  for  its  object  certain  means  of  preparing  printing  surfaces,  whether 
for  intaglio  or  surface  printing,  so  as  to  give  them  the  property  of  yielding  a  considerably 
greater  number  of  impressions  than  they  are  capable  of  doing  in  their  ordinary  or  natural 
state.  And  the  invention  consists  in  covering  the  printing  surfaces,  whether  intaglio  or 
relief,  and  whether  of  copper  or  other  soft  metal,  with  a  very  thin  and  uniform  coating  of 
iron,  by  means  of  electro-metallurgical  processes.  And  the  invention  is  applicable  whether 
the  device  to  be  printed  from  be  produced  by  engraving  by  hand,  or  by  machinery,  or  by 
chemical  means,  and  whether  the  surface  printed  from  be  the  original,  or  an  electrotype 
surface  produced  therefrom.  I  would  remark  that  I  am  aware  that  it  has  been  before  pro- 
posed to  coat  type  and  stereotypes  with  a  coating  of  copper,  to  enable  their  surfaces  to 
print  a  larger  number  of  impressions  than  they  otherwise  would  do ;  I  therefore  lay  no 
claim  to  the  general  application  of  a  coating  of  harder  metal  on  to  the  surface  of  a  softer 
one,  but  my  claim  to  invention  is  confined  to  the  application  of  a  coating  of  iron  by  means 
of  electricity  on  to  copper  and  other  metallic  printing  surfaces. 

"In  carrying  out  the  invention  I  prefer  to  use  that  modification  of  Grove's  battery 
known  as  Bunsen's,  and  I  do  so  because  it  is  desirable  to  have  what  is  called  an  intensity 
arrangement.  The  trough  I  use  for  containing  the  solution  of  iron  in  which  the  engraved 
printing  surface  is  to  be  immersed  in  order  to  be  coated,  is  lined  with  gutta  percha,  and  it 
is  45  inches  long,  22  inches  wide,  and  32  inches  deep.  In  proceeding  to  prepare  for  work, 
the  trough,  whether  of  the  size  above  mentioned  or  otherwise,  is  filled  with  water  in  com- 
bination with  hydrochlorate  of  ammonia  (sal  ammoniac)  in  the  proportion  of  one  thousand 
lbs.  by  weight  of  water  to  one  hundred  lbs.  of  hydrochlorate  of  ammonia.  A  plate  of  sheet 
iron,  nearly  as  long  and  as  deep  as  the  trough,  is  attached  to  the  positive  pole  of  the  bat- 
tery and  immersed  in  the  solution.  Another  plate  of  sheet  iron,  about  half  the  size  of  the 
other,  is  attached  to  the  negative  pole  of  the  battery,  and  immersed  in  the  solution,  and 
when  the  solution  has  arrived  at  the  proper  condition,  which  will  require  several  days,  the 
plate  of  iron  attached  to  the  negative  pole  is  removed,  and  the  printing  surface  to  be  coated 
is  attached  to  such  pole,  and  then  immersed  in  the  bath  till  the  required  coating  of  iron  is 
obtained  thereto.  If,  on  immersing  the  copper  plate  in  the  solution,  it  be  not  immediately 
coated  with  a  bright  coating  of  iron  all  over,  the  bath  is  not  in  a  proper  condition,  and  the 
copper  plate  is  to  be  removed  and  the  iron  plate  attached  and  returned  into  the  solution. 
The  time  occupied  in  obtaining  a  proper  coating  of  iron  to  a  printing  surface  varies  from 
a  variety  of  causes,  but  a  workman  after  some  experience  and  by  careful  attention  will 
readily  know  when  to  remove  the  plate  from  the  solution ;  and  it  is  desirable  to  state  that 
a  copper  plate  should  not  be  allowed  to  remain  in  the  bath  and  attached  to  the  negative 
pole  of  the  battery  after  the  bright  coating  of  iron  begins  to  show  a  blackish  appearance  at 
the  edges.  Immediately  on  taking  a  copper  plate  from  the  bath  great  care  is  to  be  ob- 
served in  washing  off  the  solution  from  all  parts,  and  this  I  believe  may  be  most  conven- 
iently done  by  causing  jets  of  water  forcibly  to  strike  against  all  parts  of  the  surface.  The 
plate  is  then  dried  and  washed  with  spirits  of  turpentine,  when  it  is  ready  for  being  printed 
from  in  the  ordinary  manner. 

"  If  an  engraved  copper  plate  be  prepared  by  this  process,  instead  of  a  comparatively 
limited  number  of  impressions  being  obtained  and  the  plate  wearing  out  gradually,  a  very 
large  number  can  be  printed  off  without  any  sign  of  wear  in  the  plate,  the  iron  coating 
protecting  it  effectually ;  the  operation  of  coating  can  be  repeated  as  many  times  as  re- 
quired, so  that  almost  an  unlimited  number  of  impressions  can  be  obtained  from  one  plate, 
and  that  a  copper  one. 

"This  process  will  be  found  extremely  valuable  with  regard  to  electrotype  plates  and 
also  for  photo-galvanic  plates,  since  they  can  be  so  protected  as  to  acquire  the  durability  of 
steel,  and  more  so,  for  a  steel  plate  will  require  repairing  from  time  to  time,  these  will  not, 
but  simply  recoating  them  whenever  it  is  found  necessary ;  by  these  means  one  electro 
copper  plate  has  yielded  more  than  12,000  impressions,  and  was  found  quite  unimpaired 
when  examined  minutely." — J.  D. 

EXGRAVIX(;  O.V  "wood.  In  order  to  make  the  whole  process  of  wood  engraving 
clear  to  the  reader,  we  will  describe  the  production  of  a  wood-ctit  from  the  time  it  leaves 
the  timber-merchant,  until  it  is  fit  for  the  hands  of  the  printer.  The  log  of  box  is  cut  into 
transverse  slices,  J  of  an  inch  in  depth,  in  order  that  the  face  of  the  cut  may  be  on  a  level 
with  the  surface  of  the  printer's  type,  and  receive  the  same  amount  of  pres.sure ;  the  block 
is  then  allowed  to  reman  some  time  to  dry,  and  the  longer  it  is  allowed  to  do  so  the  better, 
as  it  prevents  accidents  by  warping  and  splitting,  which  sometimes  happen  after  tlie  cut  is 
executed  if  the  wood  is  too  green.  The  slice  is  ultimately  trinnned  into  a  square  block, 
and  if  the  cut  be  large,  it  is  made  in  various  pieces  strongly  clamped  and  screwed  together; 
and  this  enables  engravers  to  get  large  cuts  done  in  an  incredibly  short  .'^pace  of  tiin«^  by 
putting  the  various  pieces  into  different  engravers'  hands,  and  then  screwing  the  whole  to- 
gether. The  iipper  surface  of  the  wood  is  carefully  prejiarcd  so  that  no  ine(|ualities  may 
appear  npon  it,  and  it  is  then  consigned  to  the  draughtsnian  to  receive  the  drawing.  lie 
covers  the  surface  with  a  light  coat  of  flake  white  mixed  with  weak  gum-water,  and  the 


518  ENVELOPES. 

thinner  this  coat  the  better  for  the  engraver.  The  French  draughtsmen  use  an  abundance 
of  flake  white,  but  this  is  liable  to  make  the  drawing  rub  out  under  the  engraver's  hand?,  or 
deceive  him  as  to  the  depth  of  the  line  he  is  cutting  in  the  wood.  The  old  drawings  of  the 
era  of  Durer  seem  to  have  been  carefully  drawn  with  ])en  and  ink  on  the  wood ;  but  the 
modern  drawing  being  very  finely  drawn  with  the  jiencil  or  silver  point  is  obliterated  easily, 
and  there  is  no  mode  of  "setting"  or  sectiring  it.  To  ol)viate  this  danger  the  wood-en- 
graver covers  the  block  with  paper,  and  tears  out  a  small  piece  the  size  of  a  shilling  to  work 
through,  occasionally  removing  the  paper  to  study  the  general  eficct ;  in  damp  and  wintry 
weather  he  sometimes  wears  a  shade  over  the  mouth  to  hinder  the  ^eath  from  settling  on 
the  block.  It  is  now  his  business  to  produce  in  relief  the  whole  of  the  drawing;  with  a 
great  variety  of  tools  he  cuts  away  the  spaces,  however  minute,  between  each  of  the  pencil 
lines ;  and  should  there  be  tints  washed  on  the  drawing  to  represent  sky  and  water,  he  cuts 
such  parts  of  the  block  into  a  series  of  close  lines,  which  will,  as  near  as  he  can  judge,  print 
the  same  gradation  of  tint.  Should  he  find  he  has  not  done  so  completely,  he  can  reenter 
each  line  with  a  broader  tool,  cutting  away  a  small  shaving,  thus  reducing  their  width  and 
consef|uently  their  color.  Should  he  make  some  fatal  error  that  cannot  be  otherwise  recti- 
fied, he  can  cut  out  the  part  in  the  wood,  and  wedge  a  plug  of  fresh  wood  in  the  place, 
when  that  part  of  the  block  can  be  rcengraved.  An  error  of  this  sort  in  a  wood-cut  is  a 
very  troublesome  thing;  in  copper  engraving  it  is  scarcely  any  trouble;  a  blow  with  a 
hammer  on  the  back  will  objiteiate  the  error  on  the  face,  and  produce  a  new  surface;  but 
in  wood,  the  surface  is  cut  entirely  away  except  where  the  lines  occur,  and  it  is  necessary 
to  cut  it  tfeep  enough  not  to  touch  the  paper  as  it  is  squeezed  through  the  press  upon  the 
lines  in  printing.  To  aid  the  general  effect  of  a  cut,  it  is  sometimes  usual  to  lower  the  sur- 
face of  the  block,  before  the  engraving  is  executed,  in  such  parts  as  should  ajipcar  light  and 
delicate ;  they  thus  receive  a  mere  touch  of  the  paper  in  the  press,  the  darker  parts  receiv- 
ing the  whole  pressure  and  coming  out  with  douljle  brilliancy.  When  careful  printing  is 
bestowed  on  cuts,  it  is  sometimes  usual  to  insure  this  good  eilect,  by  laying  thin  pieces  of 
card  or  paper  upon  the  tympan,  of  the  shape  needed  to  secure  pressure  on  dark  parts  only. 

Wood  engraving,  as  a  most  useful  adjunct  to  the  author,  must  always  command  a  cer- 
tain amount  of  patronage.  In  works  like  the  present,  the  author  is  greatly  aided  by  a 
diagram,  which  can  more  clearly  explain  his  meaning  than  a  page  of  letter-press ;  and  it 
can  be  set  up  and  printed  with  the  type,  a  mode  which  no  other  style  of  art  can  rival  in 
simplicity  and  cheapness.  The  taste  for  clahoiately-executed  wood  engravings  may  again 
decrease,  as  we  find  it  did  for  nearly  two  centuries;  but  it  was  never  a  lost  art,  and  never 
will  be,  owing  to  the  practical  advantages  we  speak  of,  unless  it  be  superseded  by  some 
simpler  mode  of  doing  the  same  thing  hitherto  undiscovered.  The  number  of  persons  who 
practise  wood  engraving  in  London  alone,  at  present  is  more  than  200,  and  when  we  con- 
sider the  quantity  done  in  the  great  cities  of  the  continent,  and  the  large  amount  of  book 
illu.stration  in  constant  demand,  the  creative  power  of  one  single  genius — Thomas  Bewick 
— shines  forth  in  greater  vigor  than  ever. — ¥.  W.  F. 

ENVELOPES.  The  manufacture  of  envelopes  has  so  largely  increased,  that  the  old 
method  of  folding  them  by  means  of  a  '■'•bone  foldiiiff-xtick,^'  although  a  good  workman 
could  thus  produce  3,0(i0  a  day,  was  not  capable  of  meeting  the  demand ;  hence  the  atten- 
tion of  several  was  turned  to  the  construction  of  machines  for  folding  them.  Amongst 
the  most  successful  are  the  following : — 

Envelope  folding. — In  the  envelope-folding  machine  of  Messrs.  De  la  Rue  &  Co.,  each 
piece  of  jiaper,  previously  cut  by  a  fly  press  into  the  proper  form  for  making  an  envelope, 
(and  having  the  emblematical  stamp  or  wafer  upon  it,)  is  laid  by  the  attendant  on  a  square 
or  rectangular  metal  frame  or  1)0X,  formed  with  a  short  projecting  piece  at  each  corner,  to 
serve  as  guides  to  the  paper,  and  furnished  with  a  movable  bottom,  which  rests  on  helical 
springs.  A  pre.s.^er  at  the  end  of  a  curved  compound  arm  (which  moves  in  a  vertical  plane) 
then  descends,  and  presses  the  paper  down  into  the  box,  the  bottom  thereof  yielding  to 
the  pressure ;  and  thereby  the  four  ends  or  flaps  of  the  piece  of  paper  are  caused  to  fly  up ; 
the  presser  may  be  said  to  consist  of  a  rectangular  metal  frame,  the  ends  of  which  are  at- 
tached to  the  outer  part  of  the  cm-ved  arm,  and  the  sides  thereof  to  the  inner  portion  of 
the  arm  ;  so  that  the  ends  and  sides  of  the  ])resser  can  move  independently  of  each  other. 
The  ends  of  the  presser  then  rise,  leaving  the  two  sides  of  it  still  holding  down  the  paper; 
two  little  lap[)et  pieces  next  fold  over  the  two  side  flaps  of  the  envelope ;  and  immediately 
a  horizontal  arm  advances,  carrying  a  V-shaped  piece  charged  with  adhesive  matter  or 
cement,  (from  a  saturated  endless  band,)  and  applies  the  same  to  the  two  flaps.  A  third 
lajjpet  presses  down  the  third  flap  of  the  envelo{)e  upon  the  two  cemented  flaps,  and  thereby 
causes  it  to  adhere  thereto ;  and  then  a  pressing-piece,  of  the  same  size  as  the  fini.shed  en- 
veldfic,  foMs  over  the  last  flap  and  presses  the  whole  flat.  The  final  operation  is  to  remove 
the  envelope,  and  this  is  effected  l)y  a  pair  of  metal  fingers,  with  india-iubber  ends,  which 
descend  upon  the  enveloi)e,  and,  moving  sideways,  diaw  the  envelope  off  the  bottom  of  the 
box  (the  pressing  piece  having  moved  away  and  the  bottom  of  the  box  risen  to  the  level 
of  the  platform  of  the  machine)  on  to  a  slowly-movhig  endless  band,  which  gradually  carries 


ETHER.  519 

the  finished  envelopes  away.  A  fresh  piece  of  paper  is  laid  upon  the  box  or  frame,  and 
the  above  operations  are  repeated.  This  machine  makes  at  the  rate  of  2,700  envelopes  per 
hour. 

Another  machine  for  the  same  object,  was  invented  by  Mr.  A.  Remond,  of  Birming- 
ham, and  is  that  employed  by  Messrs.  Dickinson  &  Co.  The  distinguishing  feature  of  this 
arrangement  is  the  employment  of  atmospheric  pressure  to  feed  in  the  paper  which  is  to 
form  the  envelope,  and  to  deflect  the  flaps  of  the  envelope  into  inclined  positions,  to  facili- 
tate the  action  of  a  plunger,  which  descends  to  complete  the  folding.  The  pieces  of  paper, 
cut  to  the  proper  form,  are  laid  on  a  platform,  which  is  furnished  with  a  pin  at  each  corner, 
to  enter  the  notches  in  the  pieces  of  paper,  and  retain  them  in  their  proper  position,  and 
such  platform  is  caused  alternately  to  rise  and  bring  the  upper  piece  of  paper  in  contact 
with  the  instrument  that  feeds  the  folding  part  of  the  machine,  and  then  to  descend  until  a 
fresh  piece  is  to  be  removed.  The  feeding  instrument  consists  of  a  horizontal  hollow  arm, 
with  two  holes  in  the  under  side,  and  having  a  reciprocating  movement.  When  it  moves 
over  the  upper  piece  of  paper  on  the  platform,  a  partial  vacuum  is  produced  within  it,  by  a 
suitable  exhausting  apparatus,  and  the  paper  is  thereby  caused  to  adhere  to  it  at  the  holes 
in  its  under  surface  by  the  pressure  of  the  atmosphere.  The  instrument  carries  the  paper 
over  a  rectangular  recess  or  box ;  and  then,  the  vacuum  within  it  being  destroyed,  it  de- 
posits the  paper  between  four  pins,  fixed  at  the  angles  of  the  box,  and  returns  for  another 
piece  of  paper.  As  the  paper  lies  on  the  top  of  the  box,  the  flap  which  will  be  undermost 
in  the  finished  envelope,  is  pressed  by  a  small  bar  or  presser  on  to  the  upper  edge  of  two 
angular  feeders,  communicating  with  a  reservoir  of  cement  or  adhesive  matter,  and  thereby 
becomes  coated  with  cement ;  and  at  the  same  time,  the  outermost  or  seal  flap  may  be 
stamped  with  any  required  device,  by  dies,  on  the  other  side  of  the  machine.  A  rectangu- 
lar frame  or  plunger  now  descends  and  carries  the  paper  down  into  the  box ;  the  plunger 
rises,  leaving  the  flaps  of  the  envelope  upright ;  streams  of  air,  issuing  from  a  slot  in  each 
side  of  the  box,  then  cause  the  flaps  to  incline  inwards :  and  the  folding  is  completed  by 
the  plunger  again  descending ;  the  interior  and  under  surface  of  such  plunger  being  formed 
with  projecting  parts,  suitable  for  causing  the  several  flaps  to  fold  in  proper  superposition. 
The  bottom  of  the  box  (which  is  hinged)  opens,  and  discharges  the  envelope  down  a  shoot 
on  to  a  table  below  ;  the  feeding  instrument  then  brings  forward  another  piece  of  paper ; 
and  a  repetition  of  the  above  movements  takes  place. 

EllEMACAUSIS, — slow  combustion.  This  term  has  been  applied  to  that  constant  com- 
bination of  oxygen  with  carbon  and  hydrogen,  to  form  carbonic  acid  and  water,  which  is 
unceasingly  going  on  in  nature,  as  in  the  decay  of  timber,  or  the  "heating"  of  hay  or  grain 
put  together  in  a  moist  state.  Perfect  dryness,  and  a  temperature  below  freezing,  stops 
this  eremacausis,  or  slow  combu-stion. 

ETHER,  G^lPO.  Sipi.  Sulphuric  ether,  Oxide  of  cthyle,  Ethylic  or  Vinic  ether,  &c. 
&c.  By  this  term  is  known  the  very  volatile  fluid  produced  by  the  action  on  alcohol  of 
substances  having  a  powerful  affinity  for  water. 

Preparation  on  small  scale. — A  capacious  retort  with  a  moderate-sized  tubulature  is 
connected  with  an  efficient  condensing  arrangement.  Through  the  tubulature  passes  a  tube 
connected  with  a  vessel  full  of  spirit,  sp.  gr.  0'83.  The  tube  must  have  a  stopcock  to  reg- 
ulate the  flow.  A  mixture  being  made  of  five  parts  of  alcohol  of  the  density  given  above, 
and  nine  parts  of  oil  of  vitriol,  it  is  to  be  introduced  into  the  retort,  and  a  lamp  flame  is  to 
be  so  adjusted  as  to  keep  the  whole  gently  boiling.  As  soon  as  the  ether  begins  to  come 
over,  the  stopcock  connected  with  the  spirit  reservoir  is  to  be  turned  sufficiently  to  keep  the 
fluid  in  the  retort  at  its  original  level. 

Preparation  07i  large  scale. — The  apparatus  is  to  be  arranged  on  the  same  principle, 
but,  for  fear  of  fracture,  may  be  constructed  of  cast  iron,  lined  with  sheet  lead  in  the  part 
containing  the  mixture.  The  chief  disadvantage  of  this  arrangement  is  its  opacity,  whereby 
it  becomes  impossible  to  see  the  contents  of  the  retort,  and  therefore  not  so  easy  to  keep 
the  liquid  at  its  original  level.  In  this  case  the  quantity  distilling  over  must  be  noted,  and 
the  flow  of  spirit  into  the  retort  regulated  accordingly.  The  most  convenient  mode  of  i)ro- 
ceeding  is  to  have  a  large  stone  bottle  with  a  tul)ulature  at  the  side  near  the  bottom  (like  a 
water-filter)  to  hold  the  spirit.  A  tube  passes  from  the  bottle  to  the  retort.  It  has  at  tlie 
end,  near  the  retort  or  still,  a  beiul  downwards  leading  into  the  tubulature.  If  a  glass  still 
be  used  it  must  for  safety  be  placed  in  a  sand  bath.  The  distillate  obtained,  cither  on  the 
largo  or  small  scale,  is  never  pure  ether,  Ijut  contains  sulphurous  and  acetic  acids,  bosiWes 
water  and  alcohol.  To  remove  those,  the  distillate  is  introduced,  along  with  a  little  cream 
of  lime,  into  a  large  separating  globe,  such  as  that  mentioned  under  Bromine.  The  whole 
is  to  be  well  agitated,  and  the  lime  solution  then  run  off  by  means  of  the  stopcock.  The 
purified  ether  still  contains  alcohol  and  water,  to  remove  which  it  .should  be  rectified  in  a 
water  bath.  The  fluid  will  then  constitute  the  ether  of  conuuorce.  If  the  second  distilla- 
tion be  pushed  too  far  the  ether  will,  if  evaporated  on  tlu;  hand,  leave  an  unpleasant  after 
smell,  characteristic  of  impure  ether.     If  wished  exceedingly  pure,  it  must  be  shaken  up  in 


520  EXOSMOSE  and  ENDOSMOSE. 

the  separating  globe,  with  pure  water.  This  will  dissolve  the  alcohol  and  leave  the  ether, 
contaminated  only  by  a  little  water,  which  may  be  removed  by  digestion  with  quicklime  and 
redistillation  at  a  veiy  low  temperature  on  a  hot  water  bath. 

Pure  ether  is  a  colorless  mobile  liquid,  sp.  gr.  0.71.  It  boils  at  95°  F.  The  density  of 
its  vapor  is  2.56  (calculated).     Gay  Lussac  found  it  '2.586. 

The  word  ether,  like  that  of  alcohol,  aldehyde,  &c.,  is  now  used  as  a  generic  term  to 
express  a  body  derived  from  an  alcohol  by  the  elimination  of  water.  Many  chemists  write 
the  formula  C'lPO,  and  call  it  oxide  of  ethyle  in  the  same  manner  as  they  regard  alcohol  as 
tlio  hydrated  oxide  of  tiie  same  radical.  But  there  is  no  just  reason  for  departing  from  the 
hiw  we  have  laid  down  with  reference  to  the  formulae  of  organic  compounds.  (See  Cnssi- 
iCAL  FoRMUL*.)  We  shall  therefore  write  ether  CH^'O".  This  view  has  many  advan- 
tages. We  regard,  with  (rerhardt  and  Williamson,  ether  and  alcohol  as  derived  from  the 
type  water.  Alcohol  is  two  atoms  of  water  in  which  one  equivalent  of  hydrogen  is  replaced 
by  ethyle  ;  ether  is  two  atoms  of  water  in  which  both  atoms  of  hydrogen  are  replaced  by 
tliat  radical.  But  there  is  a  large  cla.ss  of  compound  ethers  procurable  by  a  variety  of 
processes.  These  ethers  were  long  regarde<l  as  salts  in  which  oxide  of  ethyle  acted  the  part 
of  a  base.  Thus,  when  butyrate  of  soda  was  distilleil  with  alcohol  and  sulphuric  acid,  the 
resulting  product  was  regarded  as  butyrate  of  oxide  of  ethyle.  The  compound  ethers  are 
regarded  as  two  atoms  of  water  in  which  one  equivalent  of  hydrogen  is  replaced  by  the 
radical  of  an  alcohol,  and  the  other  by  the  radical  of  an  acid.  In  addition  to  those  there 
are  others  more  closely  resembling  the  simple  ethers.  They  are  founded  also  on  the  water 
type,  both  atoms  of  hydrogen  being  replaced  by  alcohol  radicals,  but  by  dili'erent  individ- 
uals. They  are  called  mixed  ethers.  The  following  formulae  show  the  chemical  constitu- 
tion of  all  these  varieties  placed  for  comparison  in  juxtaposition  with  their  type  : — 


Water,  (2  eqs.)  Common  ether.  Methylo-ethylic  ether.  Butyric  ether. 

In  the  above  formula  the  first  represents  the  type  water.  The  second  common  ether, 
the  two  equivalents  of  ethyle  replacing  the  two  of  hydrogen.  In  the  third  we  have  a  mixed 
ether,  one  of  the  equivalents  of  hydrogen  being  replaced  by  ethyle  and  the  other  by  methyle. 
The  fourth  illustra.tion  is  that  of  a  compound  ether  :  one  of  the  hydrogens  is  there  replaced 
Ijy  ethyle,  and  the  other  by  the  oxidized  radical  of  butyric  acid. 

Ether  is  largely  used  in  medicine  and  chemistry.  In  small  doses  it  acts  as  a  powerful 
stimulant.  Inhaled  in  quantity  it  is  an  anaesthetic.  It  is  a  most  invaluable  solvent  in 
organic  chemistry  for  resinous,  fatty,  and  numerous  other  bodies. — C.  G.  W. 

EXOSMOSE  and  ENDOSMOSE.  As  some  manufacturing  processes  involve  the  phe- 
nomena expressed  by  these  two  words,  it  appears  necessary  briefly  to  explain  them. 

When  two  liquids  are  separated  by  a  porous  sheet  of  animal  membrane,  unglazed  earth- 
enware, porous  stone,  or  clay,  these  liquids  gradually  diffuse  themselves ;  and  supposing  salt 
and  water  to  be  on  one  side  of  the  division,  and  water  only  on  the  other,  the  saline  solution 
passes  in  one  direction,  while  the  water,  though  with  less  intensity,  passes  in  another. 

Instead  of  the  two  words  introduced  by  Dutrochct,  Professor  Graham  proposes  the  use 
of  the  single  term  Osmose  (from  io-juoj),  impulsion. 

It  was  supposed  that  there  was,  at  the  same  time,  an  impulsive  force  acting  from  with- 
out and  another  acting  from  within  ;  that  there  was  indeed  a  currcntj^oiviiiff  hi,  and  another 
fowbu)  out.  It  however  appears  to  be  proved  that  the  os»iose  between  water  and  saline 
solutions,  consists  not  in  the  passage  of  two  liquid  currents,  but  in  the  passage  of  particles 
ot  the  salt  in  one  direction,  and  of  pure  water  in  the  other.  Professor  Graham  has  observed, 
that  common  salt  difl'uscs  into  water,  through  a  thin  membrane  of  ox-bladder  deprived  of  its 
outer  muscular  coating,  at  the  same  rate  as  when  no  membrane  is  interposed.  This  force 
plays  an  important  part  in  the  functions  of  life,  and  it  will  be  found  to  explain  many  of  the 
phenomena  associated  with  Dyeing,  Tanning,  &c. 

EXP^VNSIOX. — Experiments  by  Fresnel,  Forbes,  Powell,  Trevelyan,  and  Tyndal,  have 
a  tendency  to  prove  that  heat  occasions  a  repulsion  between  the  particles  of  matter  at  small 
distances.  If  a  heated  poker  is  laid  slantingly  ou  a  block  of  lead  at  the  ordinary  tempera- 
ture, it  will  commence  to  vibrate,  first  slowly,  and  will  increase  with  such  rapidity  as  to  pro- 
duce a  musical  note,  which  continues  for  some  time,  usually  changing  to  an  octave  at  the 
termination.  These  results  would  appear  to  prove  a  movement  amongst  the  particles  con- 
stituting the  bar. 

Some  remarkable  examples  of  expansion  are  furnished  by  the  influence  of  sunshine  on 
the  Britaimia  Tubular  Bridge. 

The  most  interesting  effect  is  that  produced  by  the  sun  shining  on  one  side  of  the  tube, 
or  on  the  top,  while  the  opposite  side  and  bottom  remained  shaded  and  comparatively  cool ; 
the  heated  portions  of  the  tube  expand,  and  thereby  warp  or  bend  the  tube  towards  the 
heated  side,  the  motion  being  sometimes  as  much  as  2^  inches  vertically  and  2^  inches 
latcrallv. 


FAULTS. 


521 


While  the  tubes  were  supported  on  the  temporary  piers  on  the  beach,  these  motions  were 
easily  observed.  An  arm  carrying  a  pencil  was  fixed  on  the  south  side  of  the  tube,  at  the 
centre,  and  a  board  was  fixed  on  a  post  independent  of  the  tube,  and  at  right  angles  to  it ; 
the  pencil  was  pressed  against  the  board  liy  a  spring,  and  the  rise  and  fall,  and  the  lateral 
motions  of  the  tube,  were  consequently  traced  on  the  board.  In  this  way  a  very  interestinnf 
diagram  was  taken  daily.  The  lowest  part  of  each  figure  is  the  starting  point,  or  normal  po- 
sition of  the  tube,  to  wliicli  the  pencil  always  accurately  returns  during  the  night.  As  soon 
as  the  sun  rises  in  the  morning  it  starts  towards  the  riglit  hand,  rising  obliquely,  the  top  and 
one  side  of  the  tube  being  warmed,  and  the  bottom  and  opposite  side  remaining  unaffected. 
It  continues  thus  till  one  o'clock,  when  the  sun,  having  ceased  to  sliine  on  the  southern  side 
begins  to  warm  the  northern  side;  the  top  still  retaining  its  high  tempei-ature,  the  tube  thus 
acquires  a  nearly  horizontal  motion  towards  the  left  hand,  the  slight  descent  in  the  line  in- 
dicating the  diminislied  effects  of  the  sun  on  the  top  as  it  gradually  sinks.  Tlie  greatest  de- 
flection to  the  left  hand  is  not  attained  until  sunset,  after  which  tlie  tube  rapidly  descends  in 
a  uniformly  curved  line  to  its  resting  point.  In  tlie  summer  time  this  point  is  hardly  at- 
tained before  the  rising  sun  compels  it  to  commence  its  journey  anew.  When  the  sun  is 
frequently  obscured  by  passing  cloud.s,  very  curious  diagrams  are  obtained.  During  the 
absence  of  the  sun  the  tube  begins  to  cool  rapidly,  and  to  return  to  its  normal  position ; 
every  passing  cloud  is  thus  beautifully  recorded. 

The  middle  of  tlie  centre  arch  of  Southwark  Iron  Bridge  rises  one  inch  in  the  height  of 
summer.  When  great  lengths  of  iron  pipe  are  laid  down  for  the  conveyance  of  steam  or 
hot  water,  sliding  joints  are  necessary  to  prevent  destruction  either  of  the  apparatus  or  of 
the  building  in  which  it  is  placed. 

F 


FALSE  TOPAZ.  A  light  yellow  pellucid  variety  of  quartz  crystal.  It  may  be  distin- 
guished from  yellow  topaz,  for  which  when  cut  it  is  frequently  sub.stituted,  by  its  difference 
of  crystalline  form,  the  absence  of  cleavage,  inferior  hardness,  and  lower  specific  gravity. 
Found  in  the  Brazils,  &c. 

FAULTS  (Failles,  Fr.),  in  mining,  are  disturbances  of  the  strata  which  interrupt  the 
miner's  operations,  and  put  him  at  a  loss  to  discover  where  the  vein  of  ore  or  bed  of  coal 
has  been  ^'^  thrown"  by  the  convulsion  of  nature.  ' 


2S8 


2S9 


291 


200 


522  FERMENTATION. 

A  mineral  vein  may  be  regarded  as  a  fissure  formed  by  the  consolidation  of  the  rocks  in 
which  it  exists,  or  by  some  movement  of  the  entire  mass,  producing  these  cracks  at  right 
angles  to  tlie  line  of  greatest  mechanical  force ;  these  have  been  eventually  filled  in  with 
the  mineral  or  metalliferous  matter  which  we  find  in  them.  After  this  has  taken  place,  there 
has  sometimes  been  a  movement  of  a  portion  of  the  ground,  and  the  mineral  vein,  or  lode, 
has  been  fractured.  A  simple  illustration  of  this  is  the  preceding,  fy.  288,  where  we  have 
the  mineral  vein  dislocated,  and  subsequently  to  the  dislocation  there  has  been  a  formation 
of  a  string  of  spathose  iron,  following  the  bendings  of  a  crack  formed  by  the  movement, 
wliich,  in  this  case,  has  been  less  than  the  width  of  the  lode.  In  the  large  majority  of  exam- 
ples the  "heave" or  "throw"  of  the  lode  has  been  very  considerable.  It  is  usual  to  speak 
of  a  fault  as  if  the  fissure  had  actually  moved  the  lode.  It  should  be  understood  that  an 
actual  movement  of  great  masses  of  the  solid  earth  is  implied,  and  consequently,  the  lode 
having  been  formed  before  the  movement,  it  is  moved  with  the  rock  in  which  it  is  enclosed. 
Fic).  290  is  the  plan  of  veins  1,  2,  3,  4,  and  an  Elvan  course  a  a,  which  have  been  dislocated 
along  the  line  [>,  c,  and  all  the  lodes  and  the  Elvan  course  moved.  In  this  case  the  move- 
ment has  probably  taken  place  from  the  North  towards  the  South.  This  disturbance  will  be 
continued  to  a  great  depth,  and  in  Jit/.  289  is  a  section  showing  the  dislocation  of  a  lode  into 
three  parts.  In  this  case  the  movement  has  probably  been  the  subsidence  of  that  portion 
of  the  ground  containing  the  lode  b,  and  the  further  subsidence  of  that  portion  containing 
the  lode  a ;  the  condition  of  the  surface  being  subsequently  altered  by  denudation.  The  in- 
clination of  a  lode  is  frequently  changed  by  these  movements:  thus  fig.  291  supposes  c  d  to 
represent  the  original  condition  of  the  lode ;  by  a  convulsion,  the  portion  a  b  has  fallen  away, 
leaving  a  chasm  between,  and  tlie  "  dip"  or  inclination  of  the  lode  is  therefore  materially 
changed.  The  direction  of  the  lode  is  frequently  altered  by  these  movements.  Many  lodes 
in  Cornwall  have  a  direction  from  the  N.  of  E.  to  the  S.  of  W.  up  to  a  fault,  on  the  other 
side  of  which  the  direction  is  changed  from  the  S.  of  E.  to  the  N.  of  W.  Where  these  dis- 
turbances are  of  frequent  occumence,  the  difficulties  of  mining  are  greatly  increased. 

FERMENTATIOX.  {Fermentation,  Fr.  ;  Gahrumj,  Germ.)  A  change  which  takes 
place,  under  the  influences  of  air  and  moisture  at  a  certain  temperature,  in  the  constituent 
particles  of  either  vegetable  or  animal  substances.  This  change  is  indicated  by  a  sensible 
internal  motion — the  development  of  heat — the  evolution  of  gaseous  products.  Fermenta- 
tiQn  may  be  divided  into  several  kinds,  as — 

Saccharine,  Butyric, 

Acetic,  Glyceric, 

Alcoholic  or  Vinous,  Lactic, 

Putrefactive,  Mucous. 

Of  the  latter  examples  but  a  brief  notice  is  required.  Mucorta  fermentation  is  established 
when  the  juice  of  the  beetroot  or  carrot  is  kept  at  a  temperature  of  100°  for  some  time, 
when  a  tumultuous  decomposition  takes  place.  All  the  sugar  disappears,  and  the  liquor  is 
found  to  contain  a  large  quantity  of  gum,  and  of  mannite  with  lactic  acid. 

Lactic  Fermentation. — If  a  solution  of  one  part  of  sugar  in  five  parts  of  water  be  made 
to  ferment,  by  the  addition  of  a  small  quantity  of  cheese  or  animal  membrane,  at  a  tem- 
])erature  of  90°  or  100°,  lactic  acid  is  formed,  which  may  be  separated  by  adding  a  little 
chalk,  the  lactate  of  lime  depositing  in  crystalline  grains.  In  lactic  fermentation  mannite 
invariably  is  produced  as  a  secondary  product,  the  formation  of  which  is  not  explained.  It 
has  been  suggested  that  the  formation  of  mannite  is  connected  with  the  production  of  suc- 
cinic acid,  which  Schmidt,  in  a  letter  to  Liebig,  states  that  he  has  found  iu  fennenting 
liquids  containing  sugar.     He  suggests  the  following  formula : 

CIPO"       +       CUPO^     =     C"H'-0" 


Mannite.  Succinic  acid.  Grape  sugar. 

Glyceric  Fermentation. — When  glycerine  is  mixed  with  yea.st,  and  kept  in  a  warm 
place  for  some  weeks,  it  is  decomposed  and  converted  into  metacetonic  acid.  This  fci- 
montation  resembles  the  last  named.  The  glycerine,  C^H'O',  forming  metacetonic  acid, 
CHV'O*,  as  sugar,  C'TPO",  does  lactic  acid,  C^IPO*,  by  loss  of  the  elements  of  water. — 
Kane, 

Butyric  Fermentation. — If  the  lactic  fermentation  is  allowed  to  proceed  beyond  the 
point  indicated  for  the  formation  of  lactate  of  lime,  the  precipitate  in  part  redissolves  with 
a  very  copious  evolution  of  hydrogen  gas  and  carbonic  acid,  and  the  liquor  contains  buty- 
rate  of  lime.  In  this  action  two  atoms  of  lactic  acid,  C"ir"0'",  produce  butyric  acid, 
CirO*,  carbonic  acid,  and  hydrogen  gas. 

Putrefactive  Fermentation.     See  Pt'TKEFACTiON. 

The  three  first  named  kinds  of  fermentation  demand  a  more  especial  attention  from 
their  importance  as  processes  of  manufacture.  Under  the  heads  respectively — Acetic  Acid, 
Beer,  Brewing,  Distillation,  Malt,  and  Wine,  will  be  found  everything  connected  with 


FERMENTATION.  523 

the  practical  part  of  the  subject ;  we  have  therefore  only  now  to  deal  with  the  chemical  and 
physical  phenomena  which  are  involved  in  the  remarkable  changes  which  take  place. 
When  vegetable  substances  are  in  contact  with  air  and  moisture,  they  undergo  a  peculiar 
change,  (decomposition.)  Oxygen  is  absorbed,  and  carbonic  acid  and  water  are  given  off, 
while  there  is  a  considerable  development  of  heat.  This  may  take  place  with  greater  or 
less  rapidity,  and  thus  ercmacausis,  fermentation,  or  combustion  may  be  the  result ;  the 
spontaneous  ignition  of  hay  (as  an  example)  being  the  final  action  of  this  absorption  of 
oxygen. 

Saccharine  Fermentation. — If  starch,  C'^H^O"  +  2H0,  be  moistened  with  an  infusion 
of  pale  malt,  it  is  rapidly  converted  into  dextrine,  C^Il'^O'",  and  hence  into  grape 
sugar,  C'*H"0" ;  this  is  especially  called  the  saccharine  fermentation,  since  sugar  is  the 
result. 

Acetic  and  Alcoholic  Fermentation. — If  sugar  is  dissolved  in  water,  it  will  remain  per- 
fectly unaltered  if  the  air  is  excluded ;  but  if  exposed  to  the  air,  a  gradual  decomposition  is 
brought  about,  and  tlie  solution  becomes  brown  and  sour.  Oxygen  has  been  absorbed,  and 
acetic  acid  produced.  If,  however,  the  sugar  is  brought  into  contact  with  any  organic  body 
which  is  in  this  state  of  change,  the  particles  of  the  sugar  participate  in  the  process,  car- 
bonic acid  is  evolved,  and  alcohol  produced.  There  are  some  substances  which  are  more 
active  than  others  in  producing  this  change.  Yeast  is  the  most  remarkable ;  but  blood, 
white  of  egg,  glue,  and  flesh,  if  they  have  begun  to  putrefy,  are  capable  of  exciting  fermen- 
tation; vegetable  albumen  and  gluten  being,  however,  more  active.  Vegetable  albumen, 
gluten,  and  legumin  differ  from  most  vegetable  bodies  in  the  large  quantity  of  nitrogen 
which  they  contain.  These  substances  exist  in  all  fruits,  and  hence,  when  fruit  is  crushed, 
the  sugar  of  the  juices  in  contact  with  the  albumen  or  gluten  being  then  exposed  to  the  air, 
oxygen  is  rapidly  absorbed,  the  nitrogenous  body  begins  to  putrefy,  and  the  sugar  passe-a 
into  fermentative  activity.  The  necessity  for  oxygen  is  at  the  commencement  of  the 
decomposition ;  when  the  putrefaction  of  the  albumen  or  gluten  has  once  begun,  it  extends 
tliroughout  the  mass  without  requiring  any  further  action  of  the  air.  These  may  be  regarded 
as  natural  ferments.  Yeast  is  an  artificial  one.  This  body  will  be  more  particularly 
described.     See  Yeast. 

To  produce  a  vinous  liquid,  it  is  necessary  that  there  shall  be  present  sugar,  or  some 
body,  as  starch  or  gum  capable  of  conversion  into  sugar,  a  certain  portion  of  water,  and 
some  ferment — for  all  practical  purposes  yeast;  and  the  temperature  should  be  steadily 
maintained  at  about  80°  F.  Both  cane  and  grape  sugar  yield  alcohol  by  fermentation,  but 
Liebig  considers  that  cane  sugar,  before  it  undergoes  vinous  fermentation,  is  converted  into 
grape  sugar  by  contact  with  the  ferment :  and  that,  consequently,  it  is  grape  sugar  alone 
which  yields  alcohol  and  carbonic  acid. 

Grape  sugar,  as  dried  at  212^,  contains  exactlv  the  elements  of  two  atoms  of  alcohol 
and  four  of  carbonic  acid.     As  2(Cni'0-)  and  4C0' "arise  from  C"H'-0'^ 

Cane  sugar  takes  an  atom  of  water  to  form  grape  sugar.  It  follows  therefore  that  cane 
sugar  should  in  fermenting  yield  more  than  its  own  weight  of  carbonic  acid  and  alcohol ; 
and  it  has  been  ascertained  by  experiment  that  100  parts  actually  give  10-1,  whilst  by  theory 
105  should  be  produced,  consisting  of  51.3  of  carbonic  acid,  and  53.7  of  alcohol. — (Kane.) 
Dr.  Pereira  has  given  the  following  very  intelligible  arrangement  to  exhibit  these 
changes : — 

PEEIAL.  COMPOSITION. 

4  oq.  carbonic 
acid    -        -     S3 

eq.  alcohol      -     92 
180  ISO  180  "iSO 

These  facts  will  sufficiently  prove  that  vinous  or  alcoholic  fermentation  is  but  a  metamor- 
phosis of  sugar  into  alcohol  and  carbonic  acid. 

Such  are  the  generally  received  views.  We  find,  however,  some  other  views  promul- 
gated which  it  is  important  to  notice. 

Liebig  calls  putrefactive  fermentation, — every  process  of  decom])osition  which,  caused 
by  external  influences  in  any  part  of  an  organic  compound,  proceeds  througli  the  entire 
mass  without  the  further  coiipcration  of  the  original  cause.  Ferjnentation,  according  to 
Liebig's  definition,  is  the  decomposition  exliibited  in  the  presence  of  putrefying  substances 
or  ferments,  by  compounds  nitrogenous  or  non-nitrogenous,  wliich  alone  are  notcapul)lo  of 
putrefiiction.  He  distinguishes,  in  both  putrefaction  and  fermentation,  processes  in  wliicli 
the  oxygen  of  the  atmosphere  continually  coiiperates,  from  such  as  are  accomplished  with- 
out further  access  of  atmospheric  air. 

Liebig  opposes  the  view  which  considers  putrefaction  and  fermentation  as  the  result  of 
vital  processes,  the  development   of  vegetable  formations  or  of  microscopic  animals.     He 


MATERIAL. 

COMPOSITION. 

1  equivalent  of 
crystallized  cane 
susar     -        -       171 

1  equivalent  of 
water     -        -          9  , 

1  eq  of 
>■  srapo 
sugar  ISO 

'     4  cq.  carbon   24 
1     8  "    carbon   4S 
I     8  "    oxygen  04 
1    4  "   oxvgcn  S2 
.  12   "    hydrog.  12 

624  FERMENTATION. 

adduces  that  no  trace  of  vegetal  formations  are  perceptible  in  milk  which  is  left  for 
Bomo  time  in  vessels  carefully  tied  over  with  blotting  paper,  not  even  after  fermenta- 
tion has  regularly  set  in,  a  large  quantity  of  lactic  acid  having  been  formed.  He  further 
remarks  of  fermentative  processes,  that  alcoholic  fermentation  having  been  observed  too 
exclusively,  the  phenomena  have  been  generalized,  while  the  explanation  of  this  process 
ought  to  bo  derived  rather  from  the  study  of  fermentative  phenomena  of  a  more  general 
character. 

Blondcau  propoimds  the  view  that  every  kind  of  fermentation  is  caused  by  the  develop- 
ment of  fungi.  Blondeau  states  that  alcoholic  fermentation  is  due  to  a  fungus  which  he 
designates  Torvula  ccrevisice  ;  whilst  another,  Penicillium  glaucum,  gives  rise  to  lactic  fer- 
mentation. The  latter  fermentation  follows  the  former  in  a  mixture  of  30  grm.  of  sugar, 
10  grm  of  yeast,  and  200  c.  c.  of  water,  which  has  undeigone  alcoholic  fermentation  at  a 
temperature  of  about  20°,  being  terminated  in  about  two  days.  Beer  yeast,  when  left  in 
contact  with  water  in  a  dark  and  moist  place,  contains,  according  to  Blondeau,  germs  both 
of  Torvula  cercvixur^  and  of  Pcnicillmm  glancmn  ;  the  former  can  be  separated  by  a  filter, 
and  will  induce  alcoholic  fermentations  in  sugar  water,  whilst  the  latter  are  extremely 
minute,  and  pass  through  the  filter ;  the  filtrate,  mixed  with  sugar  water,  gives  rise  to  lactic 
fermentation.  Acetic  i'ermentation  is  due  to  the  development  of  Torvula  acdi ;  sugar  is 
converted  into  acetic  acid,  without  evolution  of  gas,  if  500  grm.  dissolved  in  a  litre  of  water, 
be  mixed  with  200  grm.  of  casein,  and  confined  in  contact  for  a  month  at  a  temperature  of 
about  20'.  The  conversion  of  nitrogenous  substances  into  fat,  (for  instance,  of  casein,  in 
the  manufacture  of  Roquefort  cheese ;  of  fibrin  under  similar  circumstances,)  which 
Blondeau  designated  l)y  the  term  fatty  fermentation,  (fermentation  adipense,)  is  caused 
by  Penicilliitm  fflaucam  or  Torrida  viridis  ;  and  the  former  fungus  is  stated  to  act  like- 
wise in  butyric  arid  in  urea  fermentation,  (conversion  of  the  urea  into  a  caibonate  of 
ammonia.) 

Opposed  to  this  view  Schubert  has  published  an  investigation  upon  yeast.  In  order  to 
prove  that  the  action  of  yeast  is  due  merely  to  its  porosity,  he  founds  his  investigation  upon 
some  experiments  of  Brendccke,  (particularly  in  reference  to  the  statement  that  fei  menta- 
tion taking  place  in  a  solution  of  sugar  in  contact  with  porous  bodies  is  due  to  an  inqnuitj 
of  sugar;)  according  to  which  various  porous  bodies,  such  as  charcoal,  paper,  flowers  of 
stdphur,  &c.,  to  which  some  bitartrate  of  ammonia  is  added,  are  capable  of  inducing  fer- 
mentation in  a  solution  of  raw  sugar.  His  observations  are  also  based  upon  some  experi- 
ments of  his  own,  which  seem  to  indicate  that  poious  bodies,  even  without  the  addition  of 
a  salt,  are  capable  of  exciting  fermentation  in  a  solution  of  (pure?)  cane  sugar.  Whatever 
may  be  the  means  whereby  alcoholic  fermentation  is  induced,  he  states  it  to  be  indispensa- 
ble that  the  body  in  question  should  be  exposed  for  some  time  to  the  influence  of  air,  and 
that  oxygen  and  carbonic  acid  are  absorbed  by  the  fciment.  Both  oxygen  and  caibonic 
acid,  being  electro-negative  substances,  stand  in  opposition  to  the  electro  positive  alcohol, 
and  therefore  predispose  its  formation,  but  only  when  they  are  highly  condensed  by  the 
powerful  surface  attraction  of  the  yeast,  or  of  any  porous  body.  The  electiical  tension,  he 
states,  may  be  increased  by  many  .salts,  provided  that  the  latter  do  not  at  the  same  time 
chemically  affect  either  the  sugar  or  the  ferment. 

C.  Schmidt  has  communioated  the  results  of  his  experiments  to  the  Avnale  Chem. 
Pharm.  After  stating  numerous  experiments,  he  continues  :  "Nor  aie  fungi  ihc prhmim 
vwrenF;  of  saccharic  fermentation ;  the  clear  filtrate  obtained  by  throwing  almonds  crushed 
in  water  upon  a  moist  filter,  soon  induces  fcrm.cntation  in  a  solution  of  urea  and  of  grape 
sugar  ;  in  the  latter  case,  no  trace  of  ferment  cells  can  be  discovered  under  the  microscope, 
not  even  after  R^rmentation  is  fully  developed.  If  tke  solution,  still  containing  sugar,  is 
allowed  to  stand  eight  days  or  a  fortnight  after  fermentation  has  ceased,  an  exuberant 
development  of  cellular  aggregations  is  observed,  but  no  putrefaction  ensues  ;  the  fungi,  well 
washed  and  introduced  into  a  fresh  solution  of  grape  sugar,  continue  to  grow  luxuriantly, 
inducing,  however,  if  at  all,  but  very  weak  fermentation,  which  lajiidly  ceases;  hence  the 
growth  of  fungi  during  fermentative  processes  is  but  a  secondary  phenomenon.  The  in- 
crease of  the  residuary  ferment,  which  occurs  after  jTast  has  been  in  contact  with  sugar, 
arises  from  a  development  of  ferment  cellulose,  which  probably  takes  place  at  the  expense 
of  the  sugar.  If  muscle,  gelatine,  yeast,  &c.,  in  a  very  advanced  state  of  putrid  decompo- 
sition, be  introduced  into  a  solution  of  1  sugar  in  4  water,  all  phenomena  of  putrefaction  dis- 
appear; after  a  few  hours  active  fermentation  sets  in,  ferment  cells  being  formed,  and  the 
liqui<l  contains  alcohol,  but  no  mannite.  The  inactivity  of  crushed  yeast  is  due,  not  to  the 
destruction  of  the  fungi,  but  to  the  chemical  changes  which  are  induced  in  yeast  during 
the  considerable  time  necessary  for  complete  comminution.  The  cru.shed  cells,  introduced 
into  sugar  water,  give  rise  to  the  production  of  lactic  acid,  without  evolution  of  gas." 
Schmidt  is  of  opinion  that  fermentation  is  a  process  analogous  to  the  formation  of  ether. 
He  believes  that  one  of  the  constituents  of  yeast,  together  with  the  elements  of  grape  sugar, 
gives  rise  to  the  formation  of  one  or  several  eomjiounds,  which  are  decomposed  in  statu 
nascenti,  (like  sulpho-vinic  acid,)  splitting  into  alcohol  and  carbonic  acid. 


FERMENTATION.  525 

We  believe  that  the  preceding  paragraphs  fairly  represent  the  views  which  have  been 
promulgated  upon  the  phenomena  of  change,  which  are  in  many  respects  analogous  to 
those  of  combustion  and  of  vitality,  presented  in  the  fermentative  processes.  Much  has 
been  done,  but  there  are  still  some  points  which  demand  the  careful  attention  of  the 
chemist. 

In  a  practical  point  of  view,  the  question  which  arises  from  the  alteration  in  the  specific 
gravity  of  the  fluid  by  fermentation  is  a  very  important  one,  a  knowledge  of  the  original 
gravity  of  beer  being  required  to  fix  the  drawback  allowed  upon  beer  when  exported, 
according  to  the  terms  of  10  Vict.  c.  5.  By  this  act  a  drawback  is  granted  of  os.  per  barrel 
of  thirty-six  gallons,  upon  beer  exported,  of  which  "the  worts  used  before  fennentation 
were  not  of  less  specific  gravity  than  1'054,  and  not  greater  specific  gravity  than  r081  " 
and  a  drawback  of  7s.  (>d.  per  barrel  upon  beer  of  which  "  the  worts  used  before  fermexta- 
tion  were  not  of  less  specific  gravity  than  TOSl."  The  brewer  observes  the  original  gravity 
of  his  worts  by  means  of  some  foi-m  of  the  hydrometer,  and  preserves  a  record  of  his  obser- 
vation. The  revenue  officer  has  only  the  beer,  from  which  he  has  to  infer  the  orifinal 
gravity.  From  the  great  uncertainty  which  appeared  to  attend  this  question.  Professors 
Graham,  Ilofmann,  and  Redwood  were  employed  by  the  Board  of  Inland  Revenue  to  dis- 
cover how  the  original  gravity  of  the  beer  might  be  ascertained  most  accurately  from  the 
properties  of  tlie  beer  itself.  When  worts  are  fermented,  the  sugar  passes  into  alcohol 
and  they  lose  in  density,  and  assume  as  beer  a  difterent  specific  gravity.  The  gravity 
of  the  wort  is  called  the  original  gravitij — that  of  the  beer,  beer  gravity.  The  report  of 
Graham,  Hofmann,  and  Redwood,  upon  "  original  gravities,"  may  be  supposed  to  be  in 
the  hands  of  every  brewer ;  but  as  some  of  the  points  examined  materially  explain 
many  of  the  phenomena  of  vinous  fermentation,  we  have  transferred  a  few  paragraphs  to 
our  pages : — 

"  As  the  alcohol  of  the  beer  is  derived  from  the  decomposition  of  saccharine  matter 
only,  and  represents  approximately  double  its  weight  of  starch  sugar,  a  speculative  original 
gravity  might  be  obtained  by  simply  increasing  the  extract  gravity  of  the  beer  by  that  of 
the  quantity  of  starch  sugar  known  to  be  decomposed  in  tlie  fermentation.  The  inquiry 
would  then  reduce  itself  to  the  best  means  of  ascertaining  the  two  experimental  data 
namely,  the  extract  gravity  and  the  proportion  of  alcohol  in  the  beer,  particularly  of  the 
latter.  It  would  be  required  to  decide  whether  the  alcohol  should  be  determined  from  the 
gravity  of  the  spirits  distilled  from  the  beer ;  by  the  increased  gravity  of  the  beer  when  its 
alcohol  is  evaporated  oft";  by  the  boiling  point  of  the  beer,  which  is  lower  the  larger  the 
proportion  of  alcohol  present;  or  by  the  refracting  power  of  the  beer  upon  light — various 
methods  recommended  for  the  valuation  of  the  spirits  in  beer. 

"  Original  gravities  so  deduced,  however,  are  found  to  be  useless,  being  in  error  and 
always  under  the  truth,  to  an  extent  which  has  not  hitherto  been  at  all  accounted  for.  The 
theory  of  brewing,  upon  a  close  examination  of  the  process,  proves  to  be  less  simple  than  is 
implied  in  the  preceding  assumption  ;  and  other  changes  appear  to  occur  in  worts,  simul- 
taneously with  the  formation  of  alcohol,  which  would  require  to  be  allowed  for  before 
original  gravities  could  be  rightly  estimated.  It  was  found  necessary  to  study  the  gravity 
in  solution  of  each  by  itself,  of  the  principal  chemical  substances  which  are  found  in  fer- 
mented liquids.  These  individual  gravities  defined  the  possible  range  of  variation  in 
original  gravity,  and  they  brought  out  clearly  for  the  first  time  the  nature  of  the  agencies 
which  chiefly  affect  the  result. 

"  The  use  of  cane  sugar  is  now  permitted  in  breweries,  and  the  solution  of  sugar  may 
be  studied  first  as  the  wort  of  simplest  composition.  The  tables  of  the  specific  gravity  oi' 
sugar  solutions,  constructed  by  Mr.  Bate,  have  been  verified,  and  are  considered  entirely 
trustworthy.  The  numbers  in  the  first  and  third  columns  of  Table  I.,  which  follows,  a'C 
however,  from  new  observations.  It  is  to  be  remarked  that  these  numbers  have  all  refer- 
ence to  weights,  and  not  to  measures.  A  solution  of  cane  sugar,  which  contains  25  grains 
of  sugar  in  1000  grains  of  the  fluid,  has  a  specific  gravity  of  lOlO-l,  referred  to  the  gravity 
of  pure  water  taken  as  1000 ;  a  solution  of  50  grains  of  cane  sugar  in  1000  grains  of  the 
fluid,  a  specific  gravity  of  1020-2,  and  so  on.  The  proportion  oi"  carbon  contained  in  the 
sugar  is  expressed  in  the  second  column ;  the  numbers  being  obtained  from  the  calculation 
that  171  parts  by  weight  of  cane  sugar  (C'-H"0")  consist  of  72  parts  of  carbon,  11  parts  of 
hydrogen,  and  8S  parts  of  oxygen;  or  of  72  parts  of  carbon  combined  with  5)9  parts  of 
the  elements  of  water.  It  is  useful  to  keep  thus  in  view  the  proportion  of  carbon  in  sugar 
solutions,  as  that  element  is  not  involved  in  several  of  the  changes  which  precede  or 
accompany  the  principal  change  whicli  sugar  undergoes  dui-ing  fermentation,  and  which 
changes  only  affect  the  proportion  of  the  oxygen,  and  hydrogen,  or  elements  of  water, 
combined  with  the  carbon.  The  proportion  of  oxygen  and  hydrogen  in  the  altered  sugar 
increases  or  diminishes  during  the  changes  referred  to ;  but  the  carbon  remains  constant, 
and  affords,  therefore,  a  fixed  term  in  the  comparison  of  different  solutions. 


526 


FERMENTATION. 


■  Table  I. — Specific  gravity  of  solutions  of  Cane  Sugar  in  water. 


Cane  Sugar, 

in  1000  parts  by  weight. 

Carbon  in  1000  parts  by  weight. 

Specific  Gravity. 

25 

10-53 

1010-1 

50 

21-05 

1020-2 

75 

31-58 

1030-2 

100 

42-10 

1040-6 

125 

52-t53 

1051 

_ 

150 

63-16 

1061-8 

175 

73-68 

1072-0 

200 

84-21 

1083-8 

225 

94-73 

1095-2 

250 

105-20 

1106-7  ■ 

"  When  j'east  is  added  to  the  solution  of  cane  sugar  in  water,  or  to  any  other  saccharine 
solution,  and  fermentation  commenced,  the  specific  gravity  is  observed  to  fail,  owing  to  the 
escape  of  carbonic  acid  gas,  and  the  formation  of  alcohol,  which  is  specifically  lighter  than 
water;  171  grains  of  sugar,  together  with  9  grains  of  water,  being  converted  into  92  grains 
of  alcohol  and  88  grains  of  carbonic  acid,  (C'-II"0"  +  IIO  =  2C^H''0^  +  4  CO".)  But  if 
the  process  of  fermentation  be  closely  watched,  the  fall  of  gravity  in  cane  sugar  will  be 
found  to  be  preceded  by  a  decided  increase  of  gravity.  Solutions  were  observed  to  rise 
from  1055  to  1058,  or  3  degrees  of  gravity,  within  an  hour  after  the  addition  of  the  yeast, 
the  last  being  in  the  usual  proportion  for  fermentation.  When  the  yeast  was  mixed  in 
minute  quantity  only,  such  as  Vaoo  of  the  weight  of  the  sugar,  the  gravity  of  the  sugar  solu- 
tion rose  gradually  in  four  days  from  1055  to  1057-91,  or  also  nearly  3  degrees;  with  no 
appearance,  at  the  same  time,  of  fermentation  or  of  any  other  change  in  the  solution.  This 
remarkable  increase  of  density  is  owing  to  an  alteration  which  takes  place  in  the  constitu- 
tion of  the  cane  sugar,  which  combines  with  the  elements  of  water  and  becomes  starch 
sugar,  a  change  which  had  been  already  proved  by  II.  Rose  and  by  Dubrunfaut,  to  precede 
the  vinous  fermentation  of  cane  sugar.  The  same  conversion  of  cane  sugar  into  starch 
sugar,  with  increase  of  specific  gravity,  may  be  shown  by  means  of  acids  as  well  as  of  yeast. 
A  solution  of  1000  parts  of  cane  sugar  in  water,  having  the  specific  gravity  1054-64, 
became  with  1  part  of  crystallized  oxalic  acid  added  to  it  10o4-7;  and  being  afterwards 
heated  for  twenty-three  hours  to  a  temperature  not  exceeding  128°  Fahr.,  it  was  found 
(when  cooled)  to  have  attained  a  giavity  of  1057-63 — ^an  increase  again  of  nearly  3°  of 
gravity." 

The  difference  between  the  gravities  of  solutions  of  cane  sugar  and  starch  sugar  are  of 
great  practical  value,  but  these  must  be  studied  in  the  original ;  the  result,  however,  being 
"  that  the  original  gravity  of  a  fermented  liquid  or  beer  must  be  different,  according  as  it 
was  derived  from  a  wort  of  cane  sugar  or  of  starch  sugar." 

The  gravity  of  malt  wort  was  determined  to  be  intermediate  between  that  of  pure  cane 
sugar  and  staich  sugar,  and  solutions  containing  an  equal  quantity  of  carbon  exhibited  the 
following  gravities : — 

Cane  sugar  -  1072-9.  Tale  malt  -  1074-2.  Starch  sugar  -  1076-0. 

Two  other  substances  were  found  to  influence  the  original  gravity  of  the  wort :  dextrin, 
or  the  gum  of  starch,  and  caramel.  Tables  are  given  of  the  specific  gravities  of  these,  from 
wliich  the  following  results  have  been  deduced : — 


Starch  sugar, 

Dextrin, 

Caramel, 


1076 

1060-9 

1062-3 


Caramel  is  stated  to  interfere  more  than  dextrin  in  giving  lightness  or  apparent  attenua- 
tion to  fermented  worts,  without  a  corresponding  production  of  alcohol. 

"  Another  constituent  of  malt  wort,  which  should  not  be  omitted,  is  the  soluble  azotizcd 
or  albuminous  principle  derived  from  the  grain.  The  nitrogen  was  determined  in  a  strong 
wort  of  pale  malt  with  hops,  of  the  specific  gravity  1088,  and  containing  about  21  percent. 
of  solid  matter.  It  amounted -to  0-217  per  cent,  of  the  wort,  and  may  be  considered  as  re- 
presenting 3-43  per  cent,  of  albumen.  In  the  same  wort,  after  being  fully  fermented,  the 
nitrogen  was  found  to  amount  to  0-134  per  cent.,  equivalent  to  2-11  per  cent,  of  albumen. 
Tlic  loss  observed  of  nitrogen  and  albumen  may  be  considered  as  principally  due  to  the  pro- 
duction and  growth  of  yeast,  which  is  an  insoluble  matter,  at  the  cost  of  the  soluble  albu- 
minous matter.  Solutions  of  egg-albumen  in  water,  containing  3-43  and  2-11  per  cent, 
respectively  of  that  substance,  were  found  to  have  the  specific  gravities  of  1004-2  and 


FEKMENTATION.  527 

1003-1.  Hence  a  loss  of  density  has  occurred  during  fermentation  of  I'l  degree  on  a  wort 
of  1088  original  gravity,  which  can  be  referred  to  a  change  in  the  proportion  of  albuminous 
matter.  It  will  be  observed  that  the  possible  influence  of  this  substance  and  of  the  greater 
or  less  production  of  yeast  during  fermentation,  upon  the  gravity  of  beer,  are  restricted 
within  narrow  limits." 

The  reporters  proceed  : — 

"  The  process  required  for  the  determination  of  the  original  gravity  of  beer,  must  be 
easy  of  execution,  and  occupy  little  time.  It  is  not  proposed,  in  the  examination  of  a  sam- 
ple, to  separate  by  chemical  analysis  the  several  constituents  which  have  been  enumerated. 
In  fact,  we  are  practically  limited  to  two  experimental  observations  on  the  beer,  in  addition 
to  the  determination  of  its  specific  gravity. 

"  One  of  these  is  the  observation  of  the  amount  of  solid  or  extractive  matter  still 
remaining  after  fermentation,  which  is  always  more  considerable  in  beer  than  in  the  com- 
pletely fermented  wash  of  spirits.  A  known  measure  of  the  beer  might  be  evaporated  to 
dryness,  and  the  solid  i-esidue  weighed,  but  this  would  be  a  troublesome  operation,  and 
could  not  indeed  be  executed  with  great  accuracy.  The  same  object  may  be  attained  with 
even  a  more  serviceable  expression  for  the  result,  by  measuring  exactly  a  certain  (juantity 
of  the  beer,  such  as  four  fluid  ounces,  and  boiling  it  down  to  somewhat  less  than  half  its 
bulk  in  an  open  vessel,  such  as  a  glass  flask,  so  as  to  drive  off  the  whole  alcohol.  The 
liquid  when  cool  is  made  up  to  four  fluid  ounces,  or  the  original  measure  of  the  beer,  and 
the  specific  gravity  of  thi::  liquid  is  observed.  It  has  already  been  referred  to  as  to  the  ex- 
tract gravity  of^the  beer,  and  represents  a  portion  of  the  original  gravity.  Of  a  beer  of 
which  the  history  was  known,  the  original  gravity  of  the  malt  wort  was  1121,  or  121° ;  the 
specific  gravity  of  the  beer  itself  before  evaporation,  1043  :  and  the  extract  gravity  of  the 
beer  1056-7,  or  56-7°. 

"  The  second  observation  which  can  be  made  with  sufficient  facility  upon  the  beer,  is  the 
determination  of  the  quantity  of  alcohol  contained  in  it.  This  information  may  be  obtained 
most  directly  by  submitting  a  known  measure  of  the  beer  to  distillation,  continuing  the 
ebullition  till  all  the  alcohol  is  brought  over,  and  taking  care  to  condense  the  latter  without 
loss.  It  is  found  in  practice  that  four  ounce  measures  of  the  beer  form  a  convenient  quan- 
tity for  the  purpose.  This  quantity  is  accurately  measured  in  a  small  glass  flask,  holding 
1,750  grains  of  water  wlien  filled  up  to  a  mark  in  the  neck.  The  mouth  of  the  small  retort 
containing  the  beer  is  adapted  to  one  end  of  a  glass  tube  condenser,  the  other  end  being 
bent  and  drawn  out  for  the  purpose  of  delivering  the  condensed  liquid  into  the  small  flask 
previously  used  for  measuring  the  beer.  The  spirituous  distillate  should  then  be  made  up 
with  pure  water  to  the  original  bulk  of  the  1)eer,  and  the  specific  gravity  of  the  last  liquid 
be  observed  by  the  weighing-bottle,  or  by  a  delicate  hydrometer,  at  the  temperature  of  60" 
Fahr.  The  lower  the  gravity  the  larger  will  be  the  proportion  of  alcohol,  the  exact  amount 
of  which  may  be  learned  by  reference  to  the  proper  tables  of  the  gravity  of  spirits.  The 
spirit  gravity  of  the  beer  already  referred  to  proved  to  be  985-25  ;  or  it  was  14'05''  of 
gravity  less  than  1000,  or  water.  The  '  spirit  indication'  of  the  beer  was  therefore  14-05° ; 
and  the  extract  gravity  of  the  same  beer,  56-7°. 

"  The  spirit  indication  and  extract  gravity  of  any  beer  being  given,  do  we  possess  data 
sufficient  to  enable  us  to  determine  with  certainty  the  original  gravity  ?  It  has  already  been 
made  evident  that  these  data  do  not  supply  all  the  factors  necessary  for  reaching  the 
required  number  by  calculation. 

"  The  formation  of  the  extractive  matter,  which  chiefly  disturbs  the  original  gravity, 
increases  with  the  progress  of  the  fermentation;  that  is,  with  the  proportion  of  alcohol  in 
the  fermenting  li(juor.  But  we  cannot  predicate  from  theory  any  relation  which  the  forma- 
tion of  one  of  these  substances  should  bear  to  the  formation  of  the  other,  and  are  unable, 
therefore,  to  say  beforehand  that  because  so  much  sugar  has  been  converted  into  alcohol  in 
the  fermentation,  therefore  so  much  sugar  has  also  been  converted  into  the  extractive  sub- 
stance. That  a  uniform,  or  nearly  uniform,  relation,  however,  is  preserved  in  the  formation 
of  the  spirits  and  extractive  substance  in  beer-brewing,  appears  to  be  established  by  the 
observations  which  follow.  Such  an  uniformity  in  the  results  of  the  vinous  fermentation  is 
an  essential  condition  for  the  success  of  any  method  whatever  of  determining  original  grav- 
ities, at  least  within  the  range  of  circumstances  which  affect  beer-brewing.  Otherwise  two 
fermented  lif[uids  of  this  class,  which  agree  in  giving  both  the  same  spirit  indication  and 
the  same  extractive  gravity,  may  have  had  different  original  gravities,  and  the  solution  of 
our  problem  becomes  impossible." 

The  following  table,  one  of  several  of  equal  value,  gives  the  results  of  a  particular  fer- 
mentation of  cane  sugar.  "Fifteen  and  a  half  pounds  of  refined  sugar  were  dissolved  in 
10  gallons  of  water,  making  lOJ  gallons  of  solution,  of  which  the  specific  gravity  was 
lOoo'S  at  60° ;  and  after  adding  three  fluid  jjounds  of  fresh  porter  yeast,  the  specific  gravity 
was  1055-95.     The  original  gravity  may  be  taken  as  1055-3   '^55-3°.) 


528 


FEKMENTATION. 


'Table  II. — Fermentation  of  Sugar  Wort  of  original  gravity  1055*3. 


I. 

II. 

m. 

IV. 

V. 

Number  of 

Period  of 

Degrees  of  Spirit 

Degrees  of  Extract 

Degrees  of  Extract 

Observation. 

Fermentation. 

Indication. 

Gravity. 

Gravity  lost. 

Days.      Hours. 

1 

U               0 

0 

55-30 

0- 

2 

0              6 

1-59 

52-12 

S-18 

3 

0            12 

2-57 

47-82 

7-48 

4 

0            19 

3-60 

43-62 

11-68 

5 

0            23 

4-33 

40-13 

1517 

6 

1               5 

5-31 

35-50 

19-80 

7 

1            12 

6-26 

31-39 

23-91 

8 

1            19 

7-12 

27-63 

27-67 

9 

2           11 

8-59 

20-26 

85-04 

10 

3           11 

9-87 

13-40 

41-90 

11 

5           12 

10-97 

7-60 

47-70 

12 

6            12 

11-27 

4-15 

51-15 

"  Columns  iii.  and  v.  respectively  exhibit  the  spirit  which  has  been  produced,  and  the 
solid  matter  which  has  disappeared ;  the  first  in  the  form  of  the  gravity  of  the  spirit,  ex- 
pressed by  the  number  of  degrees  it  is  lighter  than  water,  or  under  1,000,  ana  the  second 
by  the  fall  in  gravity  of  the  solution  of  the  solid  matter  remaining  below  the  original  grav- 
ity 1055-3.  This  last  value  will  be  spoken  of  as  '  degrees  of  gravity  lost' ;  it  is  always  ob- 
tained by  subtracting  the  extract  gravity  (column  it.)  from  the  known  original  gravity.  To 
discover  whether  the  progress  of  fermentation  has  the  regularity  ascribed  to  it,  it  was 
necessary  to  observe  whether  the  same  relation  always  holds  between  the  columns  of  '  de- 
grees of  spirit  indication '  and  '  degrees  of  gravity  lost.'  It  was  useful,  with  this  view,  to 
find  what  degrees  lost  corresponded  to  whole  numbers  of  degrees  of  spirit  indication.  This 
can  be  done  safely  from  the  preceding  table,  by  interpolation,  where  the  numbers  observed 
follow  each  other  so  closely.  The  corresponding  degrees  of  spirit  indication  and  of 
gravity  lost,  as  they  appear  in  this  experiment  upon  the  fermentation  of  sugar,  are  as  fol- 
lows:— 


"Table  III.- 

-Fermentation  of  Sugar  Wort  of  original  gravity  1055-3. 

Degrees  of  Spirit 
Indication. 

Degrees  of  Extract 
Gravity  lost. 

Degrees  of  Spirit 
Indication. 

Degrees  of  Extract 
Gravity  lost. 

1 
2 
3 
4 
5 
6 

1-71 

4-74 

9-26 

13-48 

18-30 

22-54 

7 

8 

9 

10 

11 

27-01 
31-87 
3712 
42-55 
47-88 

"In  two  other  fermentations  of  cane  sugar,  the  degrees  of  gravity  lost,  found  to  corre- 
spond to  the  degrees  of  spirit  indication,  never  differed  from  the  numbers  of  the  preceding 
experiment,  or  from  one  another,  more  than  0-9°  of  gravity  lost.  This  is  a  sufficiently 
close  approximation. 

"  It  is  seen  from  table  IV.,  which  is  of  much  importance,  that  for  5°  of  spirit  indication, 
the  corresponding  degrees  of  gravity  lost  are  18-3°.  For  5-9°  of  spirit  indication,  the  cor- 
responding degrees  of  gravity  lost  are  22-2°. 

"  This  table  is  capable  of  a  valuable  application,  for  the  sake  of  which  it  was  constructed. 
By  means  of  it,  the  unknown  original  gravity  of  a  fermented  liquid  or  beer  from  cane  sugar 
mav  be  discovered,  provided  the  spirit  indication  and  extract  gravity  of  the  beer  are  ob- 
served. Opposite  to  the  spirit  indication  of  the  beer  in  the  table,  we  find  the  corresponding 
degrees  of  gravity  lost,  which  last,  added  to  the  extract  gravity  of  the  beer,  gives  its  origi- 
nal gravity. 

"  Suppose  the  sugar  beer  exhibited  an  extract  gravity  of  7-9°,  (1007-9,)  and  spirit  in- 
dication of  ir.  The  latter  marks,  according  to  the  table,  47-7°  of  gravity  lost,  which 
added  to  the  observed  extract  gravity,  7-9°,  gives  55-6°  of  original  gravity  for  the  beer, 
(1055-6.)" 

•Similar  tables  are  constructed  for  starch  sugar,  and  for  various  worts  with  and  without 
hops. 


FERMENTATION. 


529 


"  Table  IV. — Starch-Sugar. 

Degrees  of  Spirit  Indication,  with  corresponding  degrees  of  gravity  lost. 

Besides  the  degrees  of  gravity  lost  corresponding  to  whole  degrees  of  spirit  indication,  the  degrees  of 
gravity  lost  corresponding  to  tentlas  of  a  degree  of  spirit  indication  are  added  from  calculation. 


Degrees  of 

Spirit 

•0 

•1 

•2 

•3 

•4 

•5 

•6 

•7 

•8 

•9 

Indication. 

0 



•2 

•3 

•5 

•7 

•9 

1-0 

1-2 

1-4 

1-6 

1 

1-9 

2-1 

2-4 

2-7 

3-0 

3-3 

3-6 

3-9 

4-2 

4-6 

2 

5-0 

5-4 

5-8 

6-2 

6-6 

7-0 

7-5 

8-0 

8-5 

9-0 

3 

9-5 

9-9 

10-3 

10-7 

11-2 

11-6 

12-0 

12-4 

12-8 

13-3 

4 

13-8 

14-2 

14-6 

15-0 

15-0 

15-9 

16-3 

16-7 

17-2 

17-7 

6 

18-3 

18-7 

19-1 

19-5 

199 

20-3 

20-8 

21-2 

21-7 

22-2« 

6 

22-7 

23-1 

23-5 

23-9 

24-4 

24-7 

25-2 

25-6 

261 

26-6 

7 

27-1 

27-6 

28-1 

28-6 

29-1 

29-6 

30-0 

30-5 

31-0 

31-5 

8 

82-0 

32-5 

33-0 

33-5 

34-0 

34-5 

35-0 

35-5 

36-0 

36-6 

9 

37-2 

37-7 

38-2 

38-7 

39-2 

39-7 

40-3 

40-8 

41-3 

41-8 

10 

42-4 

42-9 

43-4 

44-0 

44-0 

45-0 

45-6 

46-1 

46-6 

47-2 

11 

47-7 

After  explaining  many  points  connected  with  the  problem,  as  it  presented  itself  under 
varied  conditions  as  it  respected  the  original  worts,  the  Report  proceeds  : — 

"The  object  is  still  to  obtain  the  spirit  indication  of  the  beer.  The  specific  gravity  of 
the  beer  is  first  observed  by  means  of  the  hydrometer  or  weighing-bottle.  The  extract 
gravity  of  the  beer  is  next  observed  as  in  the  former  method ;  but  the  beer  for  this  pur- 
pose may  be  boiled  in  an  open  glass  flask  till  the  spirits  are  gone,  as  the  new  process  does 
not  require  the  spirits  to  be  collected.  The  spiritless  liquid  remaining  is  then  made  up  to 
the  original  volume  of  the  beer  as  before.  By  losing  its  spirits,  the  beer  of  course  always 
increases  in  gravity,  and  the  more  so  the  richer  in  alcohol  the  beer  has  been.  The 
difference  between  the  two  gravities  is  the  new  spirit  indication,  and  is  obtained  by 
subtracting  the  beer  gravity  from  the  extract  gravity,  which  last  is  always  the  higher 
number. 

"  The  data  in  a  particular  beer  were  as  follows : — 


Extract  gravity, 
Beer  gravity, 


Spirit  indication, 


1044-7 
1035-1 

9.6° 


"Now  the  same  beer  gave  by  distillation,  or  the  former  method,  a  spirit  indication  of 
9-9°.  The  new  spirit  indication  by  evaporation  is,  therefore,  less  by  0-3°  than  the  old  in- 
dication by  distillation.  The  means  were  obtained  of  comparing  the  two  indications  given 
by  the  same  fermented  wort  or  beer  in  several  hundred  cases,  by  adopting  the  practice  of 
boiling  the  beer  in  a  retort,  instead  of  an  open  flask  or  basin,  and  collecting  the  alcohol  at 
the'  same  time.  The  evaporation  uniformly  indicated  a  quantity  of  spirits  in  the  beer  nearly 
the  same  as  was  obtained  by  distillation,  but  always  sensibly  less,  as  in  the  preceding  in- 
stance. These  experiments  being  made  upon  fermented  liquids  of  known  original  gravity, 
the  relation  could  always  be  observed  between  the  new  spirit  indication  and  the  degrees  of 
specific  gravity  lost  by  the  beer.  Tables  of  the  degrees  of  spirit  indication,  with  their  cor- 
responding degrees  of  gravity  lost,  were  thus  constructed,  exactly  in  the  same  manner  as 
the  tables  which  precede ;  and  these  new  tables  may  be  applied  in  the  same  way  to  ascertain 
the  original  gravity  of  any  specimen  of  beer.  Having  found  the  degrees  of  spirit  indication 
of  the  beer  by  evaporation,  the  corresponding  degrees  of  gravity  lost  are  taken  from  the 
table,  and  adding  these  degrees  to  the  extract  gravity  of  the  beer,  also  observed,  the  origi- 
nal gravity  is  found.  Thus  the  spirit  indication  (by  the  evaporation  method)  of  the  beer 
lately  referred  to,  was  9-6°,  which  mark  43°  of  gravity  lost  in  the  new  tables.  Adding 
these  to  1044-7,  the  extract  gravity  of  the  same  beer,  1087-7  is  obtained  as  the  original 
gravity  of  the  beer." 

The  results  of  the  extensive  series  of  experiments  made,  were,  that  tlie  problem  could 
be  solved  in  the  two  extreme  conditions  in  which  they  have  only  to  deal  with  the  pure 
sugars  entirely  converted  into  alcohol. 

"The  real  difficulty  is  with  the  intermediate  condition,  which  is  also  the  most  frequent 
one,  where  the  soUd  matter  of  the  beer  is  partly  starch  sugar  and  partly  extractive ;  for  no 
accurate  chemical  means  are  known  of  separating  these  substances,  and  so  determining  the 
quantity  of  each  in  the  mixture. 

Vol.  III.— 34 


530 


FERMENTATION. 


"But  a  remedy  presented  itself.  The  fermentation  of  the  beer  was  completed  by  the 
addition  of  yeast,  and  the  constituents  of  the  beer  were  thus  reduced  to  alcohol  and  extrac- 
tive only,  from  which  the  original  gravity,  as  is  seen,  can  be  calculated. 

"  For  this  purpose  a  small  but  known  measure  of  the  beer,  such  as  four  fluid  ounces, 
was  carefully  deprived  of  spirits  by  distillation,  in  a  glass  retort.  To  the  fluid,  when 
cooled,  a  charge  of  fresh  yeast,  amounting  to  150  grains,  was  added,  and  the  mixture  kept 
at  80°  for  a  period  of  sixteen  hours.  Care  was  taken  to  connect  the  retort,  from  the  com- 
mencement, with  a  tube  condenser,  so  that  the  alcoholic  vapor  which  exhaled  from  the 
wash  during  fermentation  should  not  be  lost.  When  the  fermentation  had  entirely  ceased, 
heat  was  applied  to  the  retort  to  distil  off"  the  alcohol,  which  was  collected  in  a  cooled  re- 
ceiver. About  three-fifths  of  the  liquid  were  distilled  over  for  this  purpose;  and  the  vol- 
ume of  the  distillate  was  then  made  up  with  water  to  the  original  volume  of  the  beer.  The 
specific  gravity  of  the  last  spirituous  liquid  was  now  taken  by  the  weighing-bottle.  To  ob- 
tain a  correction  for  the  small  quantity  of  alcohol  unavoidably  introduced  by  the  yeast,  a 
parallel  experiment  was  made  with  that  substance.  The  same  weight  of  yeast  was  mixed 
with  water,  and  distilled  in  another  similar  retort.  The  volume  of  this  second  distillate 
was  also  made  up  by  water  to  the  beer  volume ;  its  specific  gravity  observed,  and  deducted 
from  that  of  the  preceding  spirituous  liquid.  This  alcoKol  was  added  to  that  obtained  in 
the  first  distillation  of  the  beer,  and  the  weight  of  starch  sugar  corresponding  to  the  whole 
amount  of  alcohol  was  calculated.     This  was  the  first  result. 

"  For  the  solid  matter  of  the  beer :  the  spiritless  liquid  remaining  in  the  retort  was 
made  up  with  water  to  the  beer  volume,  and  the  specific  gravity  observed.  A  correction 
was  also  required  here  for  the  yeast,  which  is  obtained  by  making  up  the  water  and  yeast 
distilled  in  the  second  retort,  to  the  original  volume  of  the  beer,  and  deducting  the  gravity 
of  tliis  fluid  from  the  other.  The  quantity  of  starch  sugar  corresponding  to  this  corrected 
gravity  of  the  extractive  matter  was  now  furnished  by  the  table.  This  was  the  second 
result.  • 

"  The  two  quantities  of  starch  sugar  thus  obtained  were  added  together.  The  specific 
gravity  of  the  solution  of  the  whole  amount  of  starch  sugar,  as  found  iu  the  table,  repre- 
sented the  original  gravity  of  the  beer. 

"  This  method  must  give  an  original  gravity  slightly  higher  than  the  truth,  owing  to 
the  circumstance  that  the  dextrin,  albumen,  and  salts,  which  are  found  among  the  solid 
matters  dissolved  in  beer,  are  treated  as  having  the  low  gravity  of  extractive  matter,  and 
accordingly  amplified  by  about  one-sixth,  like  that  substance,  in  allowing  for  them  ulti- 
mately as  starch  sugar.  The  error  from  this  source,  however,  is  inconsiderable.  It  is  to 
be  further  observed,  that  the  error  from  imperfect  manipulation,  of  which  there  is  most 
risk  in  the  process,  is  leaving  a  little  sugar  in  the  extractive  matter  from  incomplete  fer- 
mentation. This  accident  also  increases  the  original  gravity  deduced.  The  process  has 
given  results  which  are  remarkably  uniform,  and  is  valuable  in  the  scientific  investigation 
of  the  subject,  although  not  of  that  ready  and  easy  execution  which  is  necessary  for  ordinary 
practice,  and  which  recommends  the  former  method." 

"  Table  V. — To  be  used  in  ascertaining  Original  Gravities  by  the  Distillation  Process. 
Degrees  of  Spirit  Indication  with  correspondi7\g  degrees  of  gravitij  lost  in  Malt    Worts. 


Degrees  of 

Spirit 
Indication. 

•0 

•1 

•2 

•3 

•4 

•5 

•6 

•7 

•8 

•9 

0 



•  o 

•G 

•9 

1-2 

1-5 

1-8 

2-1 

2-4 

2-7 

1 

3-0 

3-3 

3-7 

4-1 

4-4 

4-8 

5-1 

5-5 

5-9 

6-2 

2 

6-G 

7-0 

7-4 

7-8 

8-2 

8-6 

9-0 

9-4 

9-8 

10-2 

3 

10-7 

111 

11-5 

12-0 

12-4 

12-9 

13-3 

13-8 

14-2 

14-7 

4 

15-1 

15-5 

16-0 

16-4 

16-8 

17-3 

17-7 

18-2 

18-6 

19-1 

5 

19-5 

19-9 

20-4 

20-9 

21-3 

21-8 

22'2 

22-7 

231 

23-6 

6 

24-1 

24-G 

25-0 

25-5 

26-0 

26-4 

26-9 

27-4 

27-8 

28-3 

n 

28-8 

29-2 

29-7 

30-2 

30*7 

31-2 

31-7 

32-2 

32-7 

33-2 

8 

33-7 

343 

34-8 

35-4 

35-9 

3G-5 

37-0 

37-5 

38-0 

38-6 

9 

39-1 

39-7 

40-2 

40-7 

41-2 

41-7 

42-2 

42-7 

43-2 

43-7 

10 

44-2 

44-7 

451 

45-6 

46-0 

46-5 

47-0 

47-5 

48-0 

48-5 

11 

49-0 

49-6 

501 

50-6 

61-2 

51-7 

52-2 

62-7 

53-3 

53-8 

12 

54-3 

54-9 

55-4 

55-9 

56-4 

56-9 

57-4 

57-9 

58-4 

58-9 

13 

59-4 

60-0 

60-5 

61-1 

61-6 

62-2 

62-7 

63-3 

63-8 

64-3 

U 

64-8 

65-4 

65-9 

66-5 

67-1 

67-6 

68-2 

68-7 

69-3 

69-9 

15 

70-5 

FERROCYANIDES. 


531 


"  Table  VI. — To  be  used  in  ascertaining  Original  Gravities  by  the  Evaporation  Process. 
Degrees  of  Spirit  Indication  with  corresponding  degrees  of  gravity  lost  in  Malt  Worts. 


Desrees  of 

Spirit 

•0 

•1 

•2 

•3 

•4 

•0 

•6 

•7 

•8 

•9 

Indication. 

0 

__ 

•3 

•7 

1-0 

1-4 

1-7 

2-1 

2  4 

2-8 

3-1 

1 

3-5 

3-8 

4-2 

4-6 

5-0 

5-4 

5-8 

6-2 

6-6 

7-0 

2 

7-4 

7-8 

8-2 

8-7 

91 

9-5 

9-9 

10-3 

10-7 

11-1 

3 

11-5 

11-9 

12-4 

12-8 

13-2 

13-6 

14-0 

14-4 

14-8 

15-3 

4 

15-8 

16-2 

16-6 

17-0 

17-4 

17-9 

18-4 

18-8 

19-3 

19-8 

5 

20-3 

20-7 

21-2 

21-6 

22-1 

22-5 

23-0 

23-4 

23-9 

24-3 

6 

24-8 

25-2 

25-6 

26-1 

26-6 

27-0 

27-0 

28-0 

28-5 

29-0 

7 

29-5 

30-0 

30-4 

30-9 

31-3 

31-8 

32-3 

32-8 

33-3 

33-8 

8 

34-3 

34-9 

35-5 

36-0 

36-6 

37-1 

37-7 

38-3 

38-8 

39-4 

9 

40-0 

40-5 

41-0 

41-5 

42-0 

42-5 

43-0 

43-5 

44-0 

44-4 

10 

44-9 

45-4 

46-0 

46-5 

47-1 

47-6 

48-2 

48-7 

49-3 

49-8 

•     11 

50-3 

50-9 

51-4 

51-9 

52-5 

53-0 

53-5 

54-0 

54-5 

55-0 

12 

55-6 

56-2 

56-7 

57-3 

57-8 

58-3 

58-9 

59-4 

69-9 

60-5 

13 

61-0 

61-6 

62-1 

62-7 

63-2 

63-8 

64-3 

64-9 

65-4 

66-0 

14 

66-5 

67-0 

67-6 

68-1 

63-7 

69-2 

69-8 

70-4 

70-9 

71-4 

15 

72-0 

FERROCYANIDES.  The  compounds  of  the  radical  ferrocyanogen.  The  latter  radical 
is  bibasic ;  when,  therefore,  it  combines  with  hydrogen  to  form  ferrocyanic  acid,  it  takes  up 
two  atoms.  Thesft  two  atoms  of  hydrogen  can  be  replaced  by  metals  as  in  ferrocyanide  of 
potassium  or  prussiate  of  potash,  as  it  is  commonly  called.  See  Prcssiate  of  Potash. 
Ferrocyanogen  consists  of  C^N^Fe,  which  may  also  be  written  Cy'Fe,  or,  for  brevity's  sake,  Cfy. 

The  modes  of  preparing  the  ferrocyanides  differ,  according  as  the  resulting  substance  is 
soluble  or  insoluble  in  water.  The  soluble  salts,  such  as  those  with  alkalies,  are  prepared 
either  by  neutralizing  hydroferrocyanic  acid  with  the  proper  metallic  oxide,  or  by  boiling 
Prussian  blue  with  the  oxide,  the  metal  of  which  it  is  intended  to  combine  with  the  fer- 
rocyanogen. Other  methods  may  also  be  adopted  in  special  cases.  The  processes  for  pre- 
paring the  ferrocyanides  of  the  alkali  metals  on  the  large  scale  will  be  described  iu  the  arti- 
cle Prussiate  of  Potash. 

When  the  ferrocyanide  is  insoluble  in  water,  it  may  be  prepared  by  precipitating  a  salt 
of  the  metal  with  ferrocyanide  of  potassium.  Thus,  in  the  preparation  of  the  reddish  or 
purple  ferrocyanide  of  copper, 

2(CuO,SO=)  +  K^'Cfy  =r  Cu'Cfy  +  2(K0,S0'). 

The  above  equation  written  in  full  becomes  : — 

2(CuO,SO=)  +  K'C'N^Fe  =  Cu^C'N^Fe  +  2(K0,S0'). 

Ferrocyanide  of  potassium  is  much  used  as  a  test  for  various  metals,  in  consequence  of 
the  characteristic  colors  of  the  precipitates  formed  with  many  of  them.  The  principal  ferro- 
cyanides with  their  colors  and  modes  of  preparation  will  be  found  in  the  following  list: — 

Ferrocyanide  of  aluminium. — An  instable  compound  formed  by  digesting  hydrate  of 
alumina  with  ferroprussic  acid. 

Ferrocyanides  of  antimony  and  arsenic. — Neither  of  these  salts  are  known  in  a  state 
of  purity. 

Ferrocyanide  of  barium. — This  salt  may  be  prepared  by  boiling  prussian  blue  in  slight 
excess  with  baryta  water  and  evaporating  to  crystallization. 

Ferrocyanide  of  bismuth. — When  a  solution  of  ferrocyanide  of  potassium  is  added  to  a 
solution  of  a  salt  of  bismuth,  a  yellow  precipitate  is  obtained.  It  becomes  of  a  greenish 
tint  on  keeping  for  some  time. 

Ferrocyanide  of  cadmium  may  be  attained  as  a  white  precipitate  on  adding  a  solution 
of  ferrocyanide  of  potassium  to  a  soluble  salt  of  cadmium. 

Ferrocyanide  of  calcium  may  be  prepared  in  the  same  manner  as  that  of  barium,  but, 
owing  to  the  sparing  solubility  of  lime  in  water,  we  must  substitute  cream  of  lime  for 
baryta  water. 

Ferrocyanide  of  cerium  is  a  white  salt  only  slightly  soluble  in  water.  Its  properties 
are  very  imperfectly  known. 

Ferrocyanide  of  chromium. — The  protochloride  of  chromium  gives  a  yellow  precipitate 
with  ferrocyanide  of  potassium. 

Ferrocyanide  of  cobalt. — Salts  of  cobalt  give  a  pale  blue  precipitate  with  ferrocyanide 
of  potassium.     It  appears  to  decompose  on  keeping,  as  its  color  becomes  altered. 

Ferrocyanide  of  copper. — When  ferrocyanide  of  potassium  is  added  to  a  solution  of 
subchloride  of  copper,  a  white  precipitate  appears,  which,  on  exposure,  becomes  converted 


532  FILTRATION. 

into  a  purplish  red  substance,  apparently  identical  -with  the  ordinary  ferrocyanide  of  copper 
which  falls  down  on  the  admixture  of  salts  of  the  protoxide  of  copper  with  solutions  of 
ferrocyanide  of  potassium. 

Ferroci/anide  of  glucimnn  may  be  obtained,  according  to  Berzelius,  under  the  form  of 
an  amorphous  varnish,  by  decomposing  ferrocyanide  of  lead  with  a  solution  of  subsulphate 
of  glucina. 

Ferrocyanide  of  hydrogen  constitutes  ferroprussic  acid. 

Frrrocyavide  of  iron,  or  prussian  blue. — This  salt  exists  in  several  conditions,  accord- 
ing to  the  mode  of  preparation.  The  ordinary  salt  is  formed  by  adding  a  solution  of  fer- 
rocyanide of  potassium  to  a  solution  of  a  persalt  of  iron.  The  following  equation  explains 
the  reaction  that  ensues  with  the  sesquichloride : — 

2(Fe''CP)  -H  3(CfyK-)  =  3(CfyFe^)  +  6KC1. 

Ferrocyanide  of  lead  is  procured  as  a  white  precipitate  by  adding  a  solution  of  fer- 
rocyanide of  potassium  to  a  salt  of  lead. 

Ferrocyanide  of  magnesium  is  probably  best  prepared  by  neutralizing  ferroprussic  acid 
with  magnesia  or  its  carbonate.     It  forms  a  pale  yellow  salt. 

Ferrocyanide  of  manganese  may  be  obtained  as  a  white  precipitate,  on  adding  ferro- 
cyanide of  potassium  to  a  solution  of  pure  protochloride  or  protosulphate  of  manganese. . 

Ferrocyanide  of  mercury. — This  compound  cannot  be  obtained  in  a  state  of  purity  by 
precipitation.     It  has  not  been  sufficiently  examined. 

Ferrocyanides  of  molybdenum. — Molybdous  salts  give,  with  ferrocyanide  of  potassium, 
a  dark  brown  precipitate  soluble  in  excess  of  the  precipitant.  If  a  salt  of  molybdic  oxide 
be  treated  in  the  same  manner,  a  precipitate  is  obtained,  having  a  similar  appearance,  but 
insoluble  in  excess.     Molybdates  in  solution  give  precipitates  lighter  in  color  than  the  last. 

Ferrocyanide  of  nickel  is  obtained  under  the  form  of  a  pale  apple  green  precipitate,  on 
addition  of  prussiate  of  potash  to  a  salt  of  nickel. 

Ferrocya7iide  of  silver. — Ferrocyanide  of  potassium  gives  a  white  precipitate  with  sil- 
ver salts. 

Ferrocyanide  of  sodium  may  be  formed  by  the  action  of  caustic  soda  on  prussian  blue. 

Ferrocyanide  of  strontium  can  be  procured  precisely  in  the  same  manner  as  the  cor- 
responding barium  salt,  substituting  solution  of  caustic  strontia  (obtained  from  the  nitrate 
by  ignition)  for  baryta  water. 

Fen-ocyanide  of  tantalum  has  probably  never  been  obtained  pure.  Wollastou  found 
that  tantalic  acid  (dissolved  in  biuoxolate  of  potash)  gave  a  yellow  precipitate  with  prussiate 
of  potash. 

Ferrocyanide  of  thorium. — A  white  precipitate  is  produced  by  the  action  of  solution  of 
prussiate  of  potash  on  salts  of  thorium. 

Ferrocyanide  of  tin.—VwTQ  salts  of  tin,  whether  of  the  per-  or  prot-oxide,  give  white 
precipitates  with  ferrocyanide  of  potassium. 

Ferrocyanides  of  titanium. — Solutions  of  titanates  give  a  golden  brown  precipitate 
when  treated  with  solution  of  ferrocyanide  of  potassium. 

Ferrocyanides  of  vranium. — The  protochloride  gives  a  pale,  and  the  perchloride  a  dark 
reddish  brown  precipitate  with  ferrocyanide  of  potassium. 

Ferrocyanide  of  vanadium. — Salts  of  vanadic  oxide  give  pale  yellow,  and  of  vanadic 
acid,  rich  green  precipitates  with  prussiate  of  potash. 

Ferrocyanide  of  yttrium. — Chloride  of  yttrium  gives  a  white  precipitate  with  ferro- 
cyanide of  potassium. 

Ferrocyanide  of  zinc  cannot  be  prepared  by  precipitation.  It  may  be  obtained  in  the 
form  of  a  white  powder  by  the  action  of  oxide  or  carbonate  of  zinc  on  ferroprussic  acid. — 
C.  G.  "W.     For  Feruo-Cyanogex,  see  Ure's  Dictionary  of  Chemistry. 

FILTRATIOX.  Mr.  H.  M.  Witt  communicated  to  the  Philosophical  Magazine  for  De- 
cember, 1856,  an  account  of  some  experiments  on  filtration,  which  are  of  much  value. 
Many  of  his  experiments  were  made  at  the  Chelsea  Water  Works,  and  they  appear  of  such 
interest  that  we  quote  the  author's  remarks  to  some  extent. 

"  The  system  of  purification  adopted  by  the  Chelsea  Water  Works,  at  their  works  at 
Chelsea,  consisted  hitherto  (for  the  supply  has  by  this  time  commenced  from  Kingston)  in 
pumping  the  water  up  out  of  the  river  into  subsiding  reservoirs,  where  it  remained  for  six 
hours ;  it  was  then  allowed  to  run  on  to  the  filter-beds.  These  are  large  square  beds  of 
sand  and  gravel,  each  exposing  a  filtering  surface  of  about  270  square  feet,  and  the  water 
passes  through  them  at  the  rate  of  about  GJ  gallons  per  square  foot  of  filtering  surface  per 
hour,  making  a  total  quantity  of  1C87.5  gallons  per  hour  through  each  filter. 

"  The  filters  are  composed  of  the  following  strata,  in  a  descending  order: — 

ft    in. 

1.  Fine  sand 2     6 

2.  Coarser  sand -         -       1     0 

3.  Shells 0     6 

4.  Fine  gravel 0     3 

5.  Coarse  gravel 3     3 


'  FILTRATION. 


533 


These  several  layers  of  filtering  materials  are  not  placed  perfectly  flat,  but  are  disposed  in 
waves ;  and  below  the  convex  curve  of  each  undulation  is  placed  a  porous  earthenware 
pipe,  which  conducts  the  filtered  water  into  the  mains  for  distribution.  The  depth  of  water 
over  the  sand  was  4  feet  6  inches.  The  upper  layer  of  sand  is  renewed  about  every  six 
months,  but  the  body  of  the  filter  has  been  in  use  for  about  twenty  years. 

"  Samples  of  water  were  taken  and  submitted  to  examination : — 

'*  1st,  from  the  reservoir  into  which  the  water  was  at  the  time  being  pumped  from  the 
middle  of  the  river. 

"  2d,  from  the  cistern,  after  subsidence  and  filtration." 

Experiments  were  made  at  different  seasons  of  the  year ;  but  one  of  Mr.  Witt's  tables 
will  sutficiently  show  the  results. 

1.  Shows  the  quantities  of  the  several  substances  originally  present,  represented  in 
grains,  in  the  imperial  gallon  (70,000  grains)  of  water 

2.  The  amount  present  after  filtration. 

3.  The  actual  quantities  separated  in  grains  in  the  gallon  of  water. 

4.  The  percentage  ratio  which  the  amounts  separated  bear  to  the  quantities  originally 
present. 


1. 

Originally 

present. 

2. 
After  filtration. 

3. 

Amount 
separated. 

4. 

Percentage  ratio 

of  separated 

Matter. 

Total  solid  residue,  includ- 
ing suspended  matter   - 
Organic  matter 
Total  mineral  matter 
Suspended  matter     - 
Total  dissolved  salts 
Lime        .         -         .         - 

65-60 
4-05 
51-55 
28-93 
22-62 
8-719 

22-85 
1-349 

21-501 
2-285 

19-216 
8-426 

32-76 

2-70 

30-049 

26-645 

3-404 

0-293 

58-90 
66-66 
58-29 
92-10 
15-04 
3-36 

"  It  has  been  assumed  as  a  principle  that  sand  filtration  can  only  remove  bodies  me- 
chanically suspended  in  water,  but  I  am  not  aware  that  this  statement  has  been  estab- 
lished by  experiment ;  in  fact,  I  am  not  acquainted  with  any  published  analytical  examina- 
tion of  the  effects  of  sand  filtration. 

"  These  experiments  supply  the  deficiency,  and  show,  moreover,  that  these  porous  media 
are  not  only  capable  of  removing  suspended  matter,  (80  to  92  per  cent.,)  but  even  of  sepa- 
rating a  certain  appreciable  quantity  of  the  salts  from  solution  in  water,  viz.,  from  5  to  15 
per  cent,  of  the  amount  originally  present,  9  to  19  per  cent,  of  the  common  salt,  3  per 
cent,  of  the  lime,  and  5  of  the  sulphuric  acid. 

"Taking  the  purer  water  from  Kingston,  two  experiments  were  made  simultaneously 
with  the  same  water,  one  filtration  being  through  charcoal  alone,  and  the  other  through 
sand  alone,  the  sand  filter  having  an  area  of  4  square  feet,  and  consisting  of  the  following 
materials : — 

ft.  in. 

Fine  sand  -- 19 

Shells 1^ 

Gravel --  l^ 

Coarse  gravel 9 


Results  of  Sand  Filtration. 


2     9 


Original 
Water 
lued. 

After  23  hours'  action. 

After  120  hours'  action. 

Compnrison. 

Amount 
separated. 

Percentage 
of  Quantity 
separated. 

Comparison. 

Amount 
separated. 

Percentage 
ratio  of 
Quantity 

BeparatCil. 

Total  residue 
Mineral  salts 
Organic  matter  - 
Suspended  matter     ,- 
Chlorine      -        -        . 
Chloride  of  Sodium   - 

24-578 
23-687 
0-8906 
8-509 
0-8(i2 
1-420 

23-87 
22-858 
1-012 
2-663 

0-708 
0-829 

0-840 

2-88 
3-50 

24-109 

23  69 
2304 
0-C48 

0-671 
1-105 

0-888 
0-047  ■ 
0-2426 

0-191 
0-315 

8-613 
2-73 

22-16 
22-11 

After  240  hours'  actioD. 

After  376  h  sure' action. 

Total  residue 

Mineral  salts 

Organic  matter  - 

Suspended  matter 

Clilorine 

Chloride  of  Sodium   - 

24-578 
23 -087 
0-8906 
8-509 
0-862 
1-420 

22-5:34 
21-517 
0917 

1-88 
0-674 

1  i;o 

2-044 
2170 

1-629 
0188 
0310 

8316 
9161 

46-423 

21-8 

21--'. 

22-507 

21 -698 

0-809 

1-584 

2-071 
1-989 

1-925 

8-426 
8-397. 

54-85 

1 

534 


FLAT  RODS. 


"Apart  from  its  special  interest,  as  compared  with  the  following  experiment,  made 
simultaneously  through  charcoal,  the  following  points  are  in  themselves  remarkable  in  the 
results  obtained  by  this  filtration  through  sand : 

"1st.  That  the  filter  continued  increasing  in  efficacy  even  till  the  conclusion  of  the  ex- 
periment, i.  e.,  for  376  hours,  not  having  lost  any  of  its  power  when  the  experiment  was 
terminated. 

"  2d.  That  no  weighable  quantity  of  dissolved  organic  matter  was  removed  by  the 
sand  iu  this  experiment ;  but  it  must  be  remembered  that  the  quantity  originally  present 
was  but  small. 

"  3d.  Its  power  of  removing  soluble  salts  was  considerable ;  as  a  maximum,  21  percent, 
of  the  common  salt  being  separated." 

Results  of  Charcoal  Filtration. 


Original 
Water 
used. 

After  12  hours'  action. 

After  120  hours'  action. 

CompariBon. 

Amount 
separated. 

Percentage 

ratio  of 

Quantity 

separated. 

r, !             Amount 

Comparison.               ^    , 
*^                 separated. 

Percentage 
ratio  of 
Quanlily 

separated. 

To  al  residue 

Mineral  salts 

Orfranic  matter  - 

Suspended  matter 

Chlorine 

Chloride  of  Sodium    - 

24-578 
23-687 
0-&9H6 
8-509 
0-SC2 
1-420 

22-13 
21375 
0-755 

2-448 
2-312 
0-13D6 

9-906 
9-76 
15-22 

21-644 
3-06 

2-934 
0-449 

11-93 
12-79 

After  240  hours'  action. 

After  316  hours'  action. 

Total  residue      - 
Mineral  salts 
Organic  matter  - 
Suspended  matter 
Chlorine      -        .        - 
Chloride  of  Sodium   - 

24-578 
23-687 
0-S906 
3-509 
0-SG2 
1-420 

20-821 
2-79 

3-757 
0-719 

15-28 
20-43 

21-374 

20-604 

0-770 

3-204 
3-033 
0-1206 

13-03 
12-34 
13-54 

On  comparing  this  experiment  with  the  preceding,  the  following  point  comes  out  as 
showing  the  difference  between  the  effects  of  sand  and  charcoal  as  filtering  media. 

By  the  charcoal,  speaking  generally,  a  considerably  larger  quantity  of  the  total  residue 
contained  in  the  water  was  removed  than  by  the  sand,  their  maximum  results  being  respec- 
tively as  follows : — 


Amount  originally 

present. 

Amount  separated  in  Grains  in  the 

Gallon. 

Amount  separated  in  percentage  of 
the  Quantity  present. 

By  S.ind. 

By  Charcoal. 

By  Sand.                By  Charcoal. 

24-578  grains  in) 
the  gallon       j^ 

2-074 

3-757 

8-426           j            15-28 

Mr.  Way  has  also  shown  that  agricultural  soil  possesses  the  power  of  separating  the 
soluble  salts  and  organic  matter  from  water  in  a  remarkable  manner.  There  are  without 
doubt  many  natural  phenomena  which  are  immediately  dependent  upon  this  power,  possessed 
by  porous  bodies  of  all  kinds,  in  a  greater  or  a  less  degree. 

FLAT  RODS.  In  mining,  a  series  of  rods  for  communicating  motion  from  the  engine, 
horizontally,  to  the  pumps  or  other  machinery  in  a  distant  shaft. 

FLAX.  After  pulling,  the  treatment  of  flax  varies  in  different  <*ountries.  In  Russia, 
part  of  Belgium  and  Holland,  and  in  France,  the  plant  after  being  pulled  is  dried  in  the 
sun,  being  set  up  on  the  root  end  in  two  thin  rows,  the  top  interlacing  in  the  form  of  the 
letter  V  inverted.  The  sun  and  air  soon  thoroughly  dry  the  stems,  and  they  are  then  made 
into  sheaves,  and  the  seed  afterwards  beaten  oft'.  The  stems  are  steeped  subsequently. 
Another  mode,  in  general  use  in  Ireland  and  in  part  of  Flanders,  is  to  steep  the  green  stems 
immediately  after  they  are  pulled.  In  Flanders,  the  seed  is  invariably  separated  from  the 
stems  before  the  latter  are  inmiersed  in  water.  In  Ireland,  although  this  is  practised  to 
some  extent,  yet  the  great  bulk  of  the  flax  crop  is  put  in  the  water  at  once,  with  the  seed 
capsules  attached,  ami  consequently  there  is  a  very  considerable  annual  loss  to  the  country 
by  this  waste  of  a  most  valuable  product  of  the  plant.  In  the  Walloon  country  of  Belgium, 
in  its  eastern  provinces,  and  in  the  greater  part  of  Germany,  dew-rcttivg  is  practised.  That 
is,  in  place  of  immersing  the  stems  in  water,  they  are  spread  thinly  on  short  grass,  and  tlie 
action  of  the  dews  and  rains  ultimately  effects  what  immersicn  in  a  running  stream  or  pool 
aceoniplishos  in  a  nuich  shorter  time,  namely,  the  decomposition  of  the  gum  which  binds 
the  fibrus  to  the  stem  and  to  each  other.  Fibre  obtained  by  this  method  is,  however,  of 
very  inferior  quality  and  color. 


FLAX.  535 

If  the  fibre  of  flax  be  separated  from  the  stem  without  the  decomposition  of  this  matter, 
it  is  found  to  be  loaded  with  impurities,  which  are  got  rid  of  afterwards  in  the  wet-spinning, 
the  boiling  of  the  yarn,  the  subjection  of  the  woven  fabric  to  the  action  of  an  allialine  lye, 
and  the  action  of  the  atmosphere, — of  rains  and  of  alternate  dippings  in  water,  acidulated 
with  sulphuric  acid,  and  of  a  solution  of  chloride  of  lime,  which  are  all  required  to  perfect 
the  bleaching.  The  great  object,  therefore,  is  to  obtain  the  fibre  as  nearly  free  from  all  for- 
eign substances  as  possible,  and,  consequently,  the  mechanical  separation  of  it  from  the 
woody  pith  of  the  stem  is  not  to  be  recommended. 

At  various  periods  attempts  have  been  made  to  prepare  flax  fibre  without  steeping. 
Weak  acids,  solutions  of  caustic  potash,  and  of  soda,  soap,  lye,  and  lime,  have  all  been 
tried,  but  have  all  been  found  objectionable.  In  1815,  Mr.  Lee  brought  before  "  the  trus- 
tees of  the  linen  and  hempen  manufactures  of  Ireland  "  his  system  of  separating  the  fibre 
without  steeping.  He  alleged  that  a  large  yield  was  thus  obtained,  that  the  coloring  mat- 
ter could  afterwards  be  discharged  by  the  most  simple  means,  and  that  the  fibre  possessed 
greater  strength.  But  it  was  found  that  the  system  was  practically  worthless.  In  1816,  Mr. 
Pollard,  of  Manchester,  brought  forward  a  plan  of  the  same  nature,  and  proposed  to  make 
an  article  from  flax,  which  could  be  spun  on  cotton  machinery.  This  also  fell  to  the 
ground.  In  France  and  Belgium,  at  different  periods,  similar  projects  were  found  equally 
impracticable.  In  1850,  and  again  in  1857,  Mr.  Donlau  revived  the  same,  but  the  same 
fatal  objections  prevented  the  success  of  the  system.  The  fibre  was  loaded  with  impurities, 
and  the  apparently  larger  yield  over  steeped  fibre,  consisted  solely  of  these  very  impurities, 
which  had  to  be  got  rid  of  in  the  after  processes  of  manufacture.  At  the  same  time  it  must 
be  recognized  that  the  "  dry  separated  "  fibre  can  be  rendered  useful  for  one  class  of  man- 
ufactures, viz.,  those  where  no  bleaching  is  necessary,  and  its  great  strength  is  here  an 
object.  For  ropes,  rick-covers,  tarpaulins,  railway-wagon  covers,  &c.,  where  pitch  or  tar 
are  used,  and  prevent  the  decomposing  action  of  moisture  and  of  atmospheric  changes,  this 
mode  of  obtaining  flax  fibre  is  highly  useful. 

The  immersion  of  the  flax  stems  in  water,  either  as  pulled  full  of  sap,  or  after  drying, 
appears,  as  yet,  to  be  the  best  mode  of  effecting  the  decomposition  of  the  gum,  and  obtain- 
ing the  fibre  pure  or  nearly  so.  The  water  most  suitable  for  this  purpose  is  that  obtained 
from  surface  drainage,  springs  generally  holding  more  or  less  of  mineral  matters  in  solution. 
Spring  water  from  a  calcareous  soil  is  peculiarly  unsuitable,  the  carbonate  of  lime  which  it 
contains  being  adverse  to  the  putrefactive  fermentation  of  the  vegetable  extractive.  In 
Russia  much  of  the  flax  grown  is  steeped  in  lakes.  In  Holland,  it  is  always  steeped  in 
pools  filled  with  the  surface  drainage.  In  France  and  Belgium,  it  is  either  steeped  in  pools 
or  rivers.  In  England  and  Ireland  generally  in  pools,  though  occasionally  in  rivers.  The 
most  celebrated  steep-water  in  the  world  is  the  river  Lys,  which  rises  in  the  north  of 
France,  and  flows  through  the  west  of  Belgium,  joining  the  Escant  at  Ghent.  Although 
the  water  of  this  stream  has  been  analyzed,  chemists  have  not  been  able  to  discover  why  it 
should  be  so  peculiarly  favorable  to  the  steeping  of  flax.  All  along  its  course  flax  is 
steeped.  The  trade  is  in  the  hands  of  factors,  who  purchase  the  dried  stems  from  the 
growers,  and  undertake  all  the  after  processes,  selling  the  fibre  to  merchants  when  it  has 
been  prepared  for  sale.  The  apparatus  iu  use  consists  of  wooden  crates,  12  feet  long,  8 
wide,  and  3  deep.  The  sheaves  of  flax-straw  are  placed  erect  in  the  crates,  and  the  root 
ends  of  one  are  tied  to  the  top  ends  of  another,  to  secure  uniformity  of  packing.  The 
crate,  when  filled,  is  carried  into  the  river,  and  anchored  there,  the  upper  part  being  sunk, 
by  the  weight  of  stones,  6  inches  underneath  the  surface.  The  period  of  steeping  begins  in 
May,  and  ends  about  September.  The  previous  year's  crop  is  thus  steeped,  having  lain 
over  in  the  state  of  dried  straw  during  the  winter.  All  the  flax  thus  treated  produces  fibre 
of  a  yellowish  white  color,  very  soft  and  lustrous,  with  very  finely  divided  filaments,  and 
strong.  From  it  almost  exclusively  is  made  cambric,  the  finest  shirtings,  and  damask  table- 
linen.  It  is  a  strange  fact  that  flax  straw  is  brought  to  the  Lys,  from  a  great  distance,  and 
even  from  Holland,  as  no  other  water  has  yet  been  found  to  give  such  good  fibre. 

In  184Y,  a  new  system  of  steeping  was  introduced  in  Ireland,  l)y  Mr.  Schenck,  of  New 
York.  It  had  been  successfully  tried  in  America  on  hemp,  and  the  inventor  crossed  the 
Atlantic  to  try  its  efficacy  on  flax.  His  plan  consisted  in  hastening  the  putrefactive  fer- 
mentation of  the  vegetable  extractive  by  artificially  raising  the  temperature  of  the  water  to 
90^  Fahrenheit.  By  this  means,  instead  of  an  uncertain  period  of  seven  to  twenty-one 
days  being  required  for  the  steep,  according  to  the  state  of  the  weather,  and  the  tempera- 
ture of  the  atmosphere,  the  flax  was  retted  uniformly  in  sixty  hours.  The  flax  straw,  after 
the  separation  of  the  seed,  is  placed  in  wooden  or  brick  vats,  and  the  heat  is  communicated 
by  forcing  steam  into  a  coil  of  iron  or  leaden  pipes,  placed  under  a  false  bottom  perforated 
with  holes. 

The  annexed  plan  (///.  202)  of  a  retting  on  Schenck's  system,  capable  of  consuming 
annually  the  produce  of  4V)0  acres  of  flax,  and  employing,  in  all  the  operations  of  seeding, 
steeping,  drying,  and  scutching,  30  men  and  55  girls  and  boys,  or  an  aggregate  of  85  per- 
sons, win  give  an  idea  of  the  arrangements.    The  seeding-house  requires  to  be  of  large  size, 


636 


FLAX. 


as  flax  straw  is  a  bulky  article.  It  is  on  the  ground  floor,  for  the  convenience  of  carting  in 
the  flax.  The  loft  above  it  is  used  for  cleaning  and  storing  the  seed.  The  vat  and  sprt-ad- 
ing-rooms  are  in  a  building  of  one  story  only,  built  with  a  vaulted  roof  resting  on  pillars. 

292 


«»■§■»  ■»_< 


iBsS   •  M   e 


SPREAClNG     KOJM 


0  00-00  01 

10  do  00  0 


=CUTCfr-M'LL 


S^EDIHC  HCUSS 


That  part  of  the  roof  which  is  over  the  vats  has  lower  windows  to  aid  the  escape  of  the 
vapors  from  the  vats.  The  drying  sheds  at  the  top  of  the  plan  are  on  an  open  space,  well 
exposed  to  the  wind,  and  fifty  or  sixty  feet  apart.  The  hot-air  rooms  or  desiccating  house 
are  fire-proof,  each  room  capable  of  containing  the  flax  turned  out  in  one  day's  work.  The 
.scutch  mill,  with  engine  and  boiler-house,  complete  the  plan. 

The  advantages  of  this  system  were  so  manifest  that  it  was  speedily  adopted  in  many 
parts  of  the  United  Kingdom  and  of  the  Continent.  It  was  found,  however,  to  have  some 
defects.  The  small  quantity  of  water  soon  became  thoroughly  saturated  with  tlie  products 
of  decomposition,  and  tlie  fibre  of  the  flax  when  dried,  was,  consequently,  found  loaded 
with  a  yellow  powder,  offensive  to  the  smell,  causing  inconvenience  in  the  preparing  and 
spinning,  and  worse  still,  acting  prejudicially  on  the  quality  of  the  fibre  itself,  rendering  it 
harsh  and  dry. 

To  obviate  tliese  defects,  Mr.  Powniall,  of  London,  conceived  the  idea  of  pressing  the 
flax  straw,  immediately  when  taken  out  of  the  steep,  between  a  pair  of  smooth  cast-iron 
cylinders,  while,  at  the  same  time,  a  stream  of  water  played  upon  the  rollers.  By  these 
means  the  foul  water  of  the  vat  is  pressed  out  of  the  flax  stems,  which  are  flattened  and 
bruised,  thus  tending  to  aid  the  separation  of  the  bundles  of  fibres  into  minute  filaments, 
while  the  stream  of  water  effectually  washed  away  all  remaining  impurities. 

It  has  recently  been  found  that  better  fibre  can  be  obtained  by  reducing  the  temper- 
ature and  extending  the  time  of  steeping.  The  most  perfect  adaptation  of  Schenck's  sys- 
tem is  at  the  rettery  of  M.  Auguste  Scrive,  near  Lille,  and  ^7.  293  is  a  representation  of  it. 
Tanks  of  wood  or  stone  are  used,  each  to  contain  two  and  a  half  tons  of  flax  straw.  The 
straw  is  classified  according  to  quality  and  length  before  being  packed  in  the  tank.  It  is 
put  in  erect,  the  root  ends  resting  on  the  perforated  false  bottom,  and  slightly  pres.<cd  to- 
gether, but  not  so  much  as  to  prevent  a  free  circulation  of  water,  and  a  free  exit  for  the 
gases  germinated  by  the  fermentation.  The  tank  being  filled  with  water,  the  whole  is 
secured  at  the  tops  of  the  sheaves  by  narrow  strips  of  wood  four  inches  thick,  «,  catching 
the  tops  on  the  whole  length  of  each  row  of  bundles.  These  strips  of  wood  are  kept  firm 
by  cross  iron  holders  b,  secured  by  iron  bars  c,  fastened  to  pieces  of  wood  d,  worked  into 
the  side  walls  of  the  tank,  leaving  a  surface  of  four  inches  deep  of  water  over  the  top  of 
the  flax.  When  the  tank  has  been  filled  with  cold  water  through  the  wooden  shoot  e,  the 
whole  is  rapidly  heated  to  78°  Fahrenheit,  by  means  of  steam  pipes  coiled  under  the  false 
bottom.     A  second  open  shoot  f,  carries  heated  water  at  90'  to  discharge  on  the  surface, 


FLAX. 


537 


besides  two  closed  pipes  G  g,  one  of  which  brings  hot  water  of  the  same  temperature,  and 
the  other  cold  water.  When  fermentation  sets  in,  which  is  ordinarily  in  eight  hours,  the 
pipe,  as  well  as  the  shoot  of  water  at  90  \  is  set  at  play — the  first  to  create  a  continual 


293 


Ground  Plan. 


Top  of  Tank. 


Side  of  Tank. 


current  of  fresh  water  through  the  mass  of  flax,  clearing  off  the  products  of  decomposition, 
and  bringing  them  to  the  surface  ;  the  second  to  drive  this  foul  water  to  the  openings  n  h, 
where  it  is  discharged  by  the  overflow.  The  two  pipes  with  heated  and  cold  water  going  to 
the  bottom  of  the  tank,  as  well  as  the  two  shoots  containing  cold  and  hot  water,  to  go  to 
the  surface,  are  also  made  use  of  to  equalize  the  temperature  during  the  whole  operation, 
which  is  ascertained  by  the  use  of  a  thermometer  in  the  square  wooden  box  j  j.  The  steep- 
ing of  coarse  straw  requires  86  to  48  hours,  medium  qualities  50  to  60  hours,  and  the  finer 
descriptions  60  to  72  hours.  The  "  wet-rolling "  between  cylinders  after  the  steep,  is 
accompanied  by  a  shower  of  water  at  YO",  not  on  the  flax  but  on  the  top  of  the  cylinders. 
This  removes  the  remaining  impurities,  and  prepares  the  straw  for  being  easily  dried.  The 
heated  water  may  be  obtained  from  the  waste  water  of  a  spinning-mill,  or  from  a  condens- 
ing steam-engine. 

Flax  steeped  by  Schenck's  system  is  dried  in  various  ways.  Some  retters  have  drying- 
houses  with  heated  air,  others  set  up  the  flax  loosely  on  the  root  end,  in  the  field,  or  spread 
it  thinly  on  the  grass,  while  others,  again,  clasp  it  between  two  slender  pieces  of  wood  about 
a  yard  in  length,  and  hang  these  up  in  a  building  open  at  the  sides,  so  that  a  current  of 
atmospheric  air  is  constantly  passing  through. 

In  1852,  another  mode  of  retting  flax  was  introduced  by  Mr.  Watt,  of  Glasgow.  Instead 
of  immersing  the  stems  in  water,  he  subjected  them  to  the  action  of  steam.  Square  iron 
chambers  were  employed,  in  which  the  flax  straw  was  packed.  The  door  by  wliieh  it  was 
introduced  was  then  fiistened  by  bolts  or  nuts,  and  steam  was  then  driven  in.  The  steam 
penetrated  the  stems  of  the  flax  and  being  partially  condensed  on  the  top  and  sides  of  the 
iron  chamber,  a  constant  drip  of  water,  lukewarm,  fell  upon  the  flax.  In  twelve  to  fourteen 
hours  the  stems  were  removed,  and,  after  being  dried,  the  fibre  readily  separated  froln  the 
woody  core,  the  water  remaining  in  the  iron  chamber  being  of  a  dark  brown  color,  without 
offensive  odor.  The  fibre  obtained  by  this  method  was  of  a  grayish  color,  and  was  at  first 
well  thought  of  by  manufacturers ;  but  in  the  end,  on  more  extended  trials,  it  was  found  to 
possess  several  defects,  and  Watt's  sj'stcm  is  not  now  carried  out. 

Another  system  of  treating  flax  was  introduced  by  M.  Claussen,  a  Belgian,  and  for  some 
time  it  attracted  much  attention.  He  separated  the  fibre  from  the  stem  without  steeping, 
and  then  by  the  employment  of  acids  and  alkalies,  he  got  rid  of  the  vegetable  extractive 
and  other  impurities,  and  produced  a  fibrous  mass  .strongly  resembling  cotton.  He  pro- 
fessed to  make  an  article  capal)le  of  being  sp\m  with  cotton  or  wool.  The  higher  value  of 
flax  fibre,  however,  was  a  great  obstacle,  and  at  present  the  only  use  made  of  his  process  is 


538 


FLAX. 


to  convert  scutching  tow — the  refuse  flax  fibre — into  an  article  to  be  spun  with  wool,  and 
even  this  is  practised  to  but  a  very  small  extent. 

Messrs.  Burton  and  Pye's  patent  {fig.  294)  is  a  modification  of  the  hot  water  steep.    By 

294 


1 


this  process,  the  flax  straw,  after  the  seed  is  removed,  is  passed  through  a  machine  com- 
posed of  plain  and  crimping  rollers,  by  the  combined  action  of  which  the  woody  part  is  ren- 
dered easily  separable  from  the  fibre.  The  latter  is  then  placed  in  a  vat,  holding  about  a 
ton,  which  is  subsequently  filled  with  cold  water.  This  vat  has  a  perforated  false  bottom, 
under  which  steam,  with  a  pressure  of  50  lbs.  to  an  inch,  is  introduced  and  disseminated  by 
perforated  tubes.  Another  tube  eonvej^s  into  the  vat  a  cold  mixture  of  fuller's  earth  in 
water.  The  introduction  of  the  mixture  and  the  steam  is  continued  until  the  liquid  in  the 
vat  reaches  80°  Fahrenheit.  The  flax  remains  in  it  at  this  temperature  for  thirty  hours, 
when  the  surface  of  the  liquid  is  covered  with  a  saponaceous  froth.  Then  an  apparatus  of 
cross  bars  of  wood,  closely  fitting  into  the  interior  of  the  vat  and  pressed  by  two  powerful 
screws,  expresses  the  impurities  from  the  fibre.  The  supply  of  the  fuller's  earth  is  stopped, 
and  cold  water  is  alone  supplied  with  the  steam,  so  regulated  that  the  temperature  is  by 
degrees  raised  to  150°,  the  pressure  being  continued  until  the  water  appears  free  from  im- 
purities. The  water  is  then  withdrawn  from  the  vat  through  a  valve  in  the  bottom,  and  a 
pressure  equal  to  200  tons  is  applied  to  the  mass  of  the  flax.  It  remains  under  this  pres- 
sure for  four  hours,  when  it  is  half  dry.  It  is  then  taken  out  and  dried  in  sheds  open  at  the 
sides  to  the  air.  The  fibre  produced  by  Mr.  Pye's  method  appears  of  good  quality  and 
strong,  but  the  system  has  not  as  yet  been  carried  out  on  a  sufficiently  large  scale  to  admit 
of  a  decided  opinion  on  its  merits. 

The  same  may  be  said  of  the  plan  of  M.  Terwangue,  of  Lille,  who  employs  hot  water  at 
a  temperature  of  15°  to  17°  centigrade,  60°  Fahr.,  in  which  chalk  and  charcoal  have  been 
placed.  His  process  requires  seventy-two  hours  on  the  average,  and  he  employs  brick 
tanks.     The  water  is,  as  in  all  the  preceding  cases,  heated  by  steam. 

Before  leaving  the  subject  of  steeping,  reference  may  be  made  to  a  process  patented  by 
Mr.  F.  M.  Jennings,  of  Cork,  by  means  of  which  coarse  flax  fibre  is  rendered  capable  of 
being  subdivided  into  minute  filaments,  or,  in  other  words,  made  fine.  While  the  fibre  of 
cotton  is  incapable  of  subdivision,  that  of  flax,  as  viewed  through  the  microscope,  is  seen  to 
consist  of  a  bundle  of  extremely  delicate  filaments  adhering  together,  so  that  fine  and  coarse 
flax  are  really  relative  terms.  Mr.  Jennings  throws  down  upon  the  flax  fibre,  as  it  appears 
in  commerce,  a  small  quantity  of  oil,  say  half  an  ounce  to  the  pound  of  fibre.  He  effects 
this  by  boiling  the  fibre  in  an  alkaline  soap  lye,  washing  with  water,  and  then  boiling  in 
water  slightly  acidulated  with  pyroligneous  acid  which  decomposes  the  soap  and  leaves  its 
fatty  constituent  on  the  fibre.  It  is  afterwards  washed  once  more,  and  is  then  found  to  be 
«oft  and  silky,  and  the  coarse  fibres  capable  of  being  readily  separated  on  the  hackle,  while 


FLAX. 


539 


the  strenRth  is  not  apparently  reduced.     There  is  also  a  greater  facility  in  the  bleaching  of 
the  iS  made  from  flaz  fibre  so  treated,  and  less  loss  in  weight  in  the  bleaching  process. 


295 


While  some  of  the  inventions  referred  to  for  hastening  and  equalizing  the  time  of  steep- 
ine  are  being  carried  out  to  a  considerable  extent,  and  promise  well,  when  brought  to  a 
olater  degree  of  perfection  by  experience  in  practical  working,  to  be  yet  more  largely  em- 
ployed thi  great  mass  of  the  flax  grown  throughout  the  globe  is  steeped  in  pools,  m-ers  or 
lakes.  '  It  wTll,  therefore,  be  most  advisable  to  follow  the  processes,  as  practised  b)  tlic 

^''^  When'tlfe^'flax  has  been  sufficiently  retted,  i.  e.,  when  on  taking  a  few  stalks  out  of  the 
water  the  fibre  can  be  readily  separated  by  the  fingers  along  its  ''^"^''•';  ^^'"-''iV  ti!l^\l  ,1 
woody  interior,  it  is  removed  from  the  water  and  placed  to  drum  on  the  banks  of  the  poo 
driver.  It  is  then  taken  to  a  closely  shorn  grass-field  or  old  pasture  land  and  spread 
thinly  and  evenly  on  the  ground.  In  Flanders,  however,  the  system  of  drying  ,s  somewhat 
differ^ent.  Instead  of  being  spread  flat  on  the  ground,  the  sheaves  are  divided  in  o  four 
portions,  and  these  are  se^  upright  in  capdlcs,  i.  e.,  the  butt  ends  are  spread  widely  out  m 
a  circle  on  the  ground,  and  the  tops  are  kept  close  together.  By  th,s  means  the  sun  and 
air  soon  dry  the  flax.  When  thoroughly  dried  it  is  tied  up  m  sheaves,  and  after  remauung 
a  few  days ^n  the  usual  form  of  a  grain  stack  it  is  ricked.  In  this  state  it  may  rcmam  lor 
years  without  the  fibre  being  deteriorated. 


m 


540 


FLAX. 


The  next  process  is  termed  scutching,  (French,  teillaffc,)  and  is  intended  to  separate  the 
fibre  from  the  woody  matter  of  the  stem,  and  thus  to  make  it  fit  for  the  spinner.  The  first 
part  of  this  process  is  to  bruise  the  stems  thoroughly  so  that  wliile  the  fibre,  from  its  te- 
nacity, is  intact,  the  brittle  woody  part  is  flattened  and  broken  in  such  a  manner  as  to  admit 
of  its  easily  being  beaten  off  by  the  action  of  the  scutch-blade  or  scutch-mill.  In  most 
countries  the  bruising  is  done  by  hand.  In  Flanders  and  France  the  flax  straw  is  first  laid 
flat  on  the  ground,  the  sheaf  being  untied  and  spread  thinly,  and  the  workman,  placing  his 
foot  upon  it,  beats  it  with  an  instrument  called  a  tnail,  having  a  curved  handle  and  a 
heavy  square  indented  mallet, ^y.  296. 


The  next  part  of  the  process  is  to  give  the  flax  repeated  blows  in  a  machine  termed  a 
brace  or  braque,fig.  297.  This  is  generally  made  of  wood,  but  sometimes  of  iron,  and  con- 
sists of  two  rows  of  grooves  t  t,  the  uj)per  one  moving  on  a  pivot  at  the  socket  s.  A  stout 
pole  p  runs  from  end  to  end  of  the  upper  row  of  teeth.  The  latter  are  wedge-shaped,  4} 
inches  deep,  1^  inches  thick  at  top,  and  33|  inches  long  from  the  head  h  to  the  socket  s. 
The  head  weighs  about  8  lbs.  and  is  10  inches  long,  and  3J  inches  thick.  The  lower  row 
of  teeth  consists  of  four,  while  the  upper  is  three,  fitting  into  the  interstices.  The  best 
wood  for  the  machine  is  that  of  the  apple-tree. 

Next  comes  the  scutching  proper,  still  following  the  Belgian,  French,  and  Dutch  method 
of  hand-work.  After  the  flax  has  been  bruised  by  the  mail,  and  crushed  by  the  braguc,  it 
is  ready  for  the  scutching  process.  In  Belgium  and  France  the  method  pursued  is  by  the 
employment  of  a  wooden  stand,  {fg.  298.)    A  broad  plank  of  pine  or  beech,  about  4  feet 


298 


^ 


299 


high,  and  rather  more  than  a  foot  broad,  about  f  inch  thick,  is  fixed  in  a  wooden  sole  b.  3 
feet  from  this  sole  is  a  cut  in  the  wood  of  the  upright  plank,  about  H  to  2  inches  wide. 
This  cut  serves  for  the  introduction  of  a  handful  of  the  flax  straw,  bruised  as  before  de- 


FLAX. 


541 


scribed,  and  the  workman,  holding  it  three-fourths  exposed  through  the  slit,  beats  it  with  a 
tool  called  the  scutch-blade,  fig.  299.  It  is  made  of  walnut  wood,  and  is  very  tough  and 
flexible.  In  Ireland  the  system  of  scutching  by  hand  is  very  rude,  and  prevails  chiefly  in 
the  western  counties.  A  brake  similar  to  that  of  Belgium  is  employed,  but  instead  of  the 
Belgian  scutch  tool,  a  rude  instrument  is  employed,  generally  of  ash-wood,  in  the  form  of  a 
sword  blade. 

It  must  be  stated  that  the  system  of  hand-scutching  is  only  to  be  recommended  where 
the  quality  of  the  flax  fibre  is  so  superior  as  to  render  economy  in  waste  of  primary  im- 
portance, or  else  where  the  wages  of  labor  are  so  low,  as  to  render  the  power  of  machinery 
of  little  consequence,  as  regards  economy.  But,  where  wages  are  high,  and  flax  of  medium 
or  low  quality,  there  is  no  question  that  machine  scutching  is  the  most  advisable  and  the 
most  economical.  This  has  been  especially  recognized  in  Ireland,  where,  in  1857,  1037 
scutch  mills  were  in  operation,  when  the  growers  sent  their  crops  to  be  prepared  for  mar- 
ket, at  a  reasonable  rate,  much  less  than  hand  scutching  would  have  cost.  Scutch  mills 
have  been  introdujed  with  advantage  into  Russia,  Prussia,  Austria,  Denmark,  Holland,  Bel- 
gium, France,  Italy,  and  Egypt.  In  Ireland,  although  in  several  districts  flax  is  scutched 
by  hand,  machine  or  mill  scutching  has  been  for  more  than  half  a  century  in  operation.  As 
in  the  hand-scutching,  the  operation  consists  of  two  processes :  first,  the  bruising  of  the 
stems,  and  secondly,  the  beating  away  of  the  woody  parts  from  the  fibre.  The  original  sys- 
tem of  bruising  is  still  very  general.  It  consists  of  a  set  of  three  smooth  wooden  rollers, 
one  underneath  and  the  two  others  above  it,  parallel  to  each  other,  and  one  of  them  hor- 
izontal to  the  lower  roller.  The  laborer  sits  opposite  the  lower  roller,  and  inserts  a  handful 
of  flax  straw  between  the  latter  and  the  upper  one,  which  is  horizontal  to  it.  The  flax  being 
drawn  in  and  bruised  between  these,  passes  up  between  the  two  upper  rollers,  and  reappears 
at  the  outside.  It  is  again  put  through  once  or  twice,  according  to  its  thickness,  or  to  its  being 
more  or  less  steeped,  and  the  fibre,  consequently,  more  or  less  easily  freed  from  the  ligneous 
part.  The  scutching  apparatus  consists  of  a  wooden  shaft,  to  which  are  attached,  at  intervals, 
like  radii  of  a  circle,  short  arms,  to  which  are  nailed  the  stocks^  which  are  parallelogram-shaped 
blades  of  hard  wood,  with  the  edges  partially  sharpened.  The  laborer  stands  beside  an  upright 
wooden  plank,  very  similar  to  that  figured  in  the  description  of  the  Belgian  hand-scutching 
apparatus,  and  through  just  such  a  slit  exposes  one  half  of  the  handful  of  bruised  flax  straw 
to  the  action  of  the  stocks,  which  revolve  with  rapidity  along  with  the  shaft  and  strike  the 
flax  straw,  beating  off  the  ligneous  matter  and  leaving  the  fibre  clear.  When  the  end  ex- 
posed to  the  stocks  is  cleaned,  the  workman  turns  the  handful  and  exposes  the  other  end. 
It  is  usual  to  have  a  set  of  either  two  or  three  men  at  as  many  different  stands,  and,  instead 
of  each  thoroughly  clearing  out  the  handful  of  flax,  he  only  partially  does  so  ;  the  second 


300 


542 


FLAX. 


then  takes  it  up  and  finishes  it ;  or,  if  there  be  three  in  the  set,  he  does  not  quite  clean  it, 
but  hands  it  over  to  the  third  to  do  so.  In  the  latter  case,  the  first  workman  is  called  the 
buffer,  the  second  the  middler,  and  the  third  the  finisher.  The  motive  power  in  these  scutch- 
mills  is  generally  water ;  in  some  cases  they  are  wind-mills,  and  in  a  few  instances  they  are 
driven  by  horses.  Latterly  the  use  of  steam  engines  has  considerably  increased,  as  being 
more  to  be  depended  upon  than  water,  which  frequently  fails  in  a  dry  season.  It  has  been 
found  that  the  woody  waste  produced  in  the  scutching  is  quite  sufficient  fuel  for  the  boiler, 
without  its  being  necessary  to  purchase  coal  or  peat,  and  this  waste  had  hitherto  been  ap- 
plied to  no  useful  purpose,  being  with  the  greatest  difficulty  decomposable  for  manure. 

The  first  improvement  on  this  old  scutch-mill  apparatus  was  the  introduction,  by  Messrs. 
MacAdam  Brothers,  of  Belfast,  of  a  machine  for  bruising  the  flax  straw,  prior  to  steeping, 
and  it  has  since  been  extensively  employed  with  very  satisfactory  results.  It  consists  of  a 
series  of  fluted  rollers,  running  vertically  on  each  other,  the  flutings  varying  in  width,  the 
widest  set  being  the  first  through  which  the  flax  straw  passes,  and  the  others  diminishing  in 
width,  until  the  finest  is  the  last.  While  acting  strongly  on  the  ligneous  matter,  at  the 
same  time  bruising  and  crimping  it  and  reducing  it  almost  to  powder,  it  does  not  injure  or 
disarrange  the  fibre.  One  breaking  machine  of  this  construction  is  capable  of  supplying  12 
scutching  stands  of  the  ordinary  mill.  It  is  attended  by  two  boys,  one  to  feed  the  flax 
straw  into  the  machine  by  means  of  a  feeding  table,  and  the  other  to  remove  it  at  the  op- 
posite extremity.  Once  passing  through  the  machine  is  quite  sufficient  to  prepare  the  flax 
straw  thoroughly  for  being  scutched.  The  force  required  to  drive  it  is  one  horse-power. 
Fig.  300  will  best  show  its  construction  and  mode  of  action. 

It  having  been  found  that  many  disadvantages  were  inherent  in  the  old  scutch-mill,  sev- 
eral persons  have  set  themselves  to  work  to  supply  a  machine  which  would  reduce  the  cost 
of  labor,  obviate  the  necessity  of  obtaining  skilled  workmen,  and  diminish  the  great  waste  of 
fibre,  which  was  but  too  frequent  in  the  ordinary  mill.  Among  the  most  successful  of  these 
scutching  machines  is  an  invention  of  Mr.  MacBride,  of  Armagh,  Ireland,  ^^s.  301,  302.    It 

301 


consists  of  a  cast-iron  frame,  at  each  end  of  which  is  a  compartment,  enclosing  a  double  set 
of  beaters  of  peculiar  construction,  which  revolve  rapidly  in  a  contrary  direction,  striking 
alternately  on  each  side  of  the  flax,  as  it  is  submitted  to  their  action,  and  thoroughly  remov- 
ing the  woody  part,  which  falls  down  in  dust  into  a  pit  or  hollow  under  the  machine.  In 
order  to  carry  the  flax  gradually  through  the  machine  aud  present  it  in  a  proper  manner  to 


FLAX. 


543 


the  beaters,  in  succession,  an  endless  double  rope  is  introduced,  carried  in  the  hollow  of  a 
large  grooved  wheel,  in  which  it  is  kept  tight  by  means  of  tension  weights.  The  flax  straw, 
made  into  handfuls,  is  introduced  at  a,  under  the  double  rope  at  one  end  of  the  machine, 
and  is  at  once  grasped  by  it  firmly,  rather  above  its  middle,  and  carried  along  slowly,  by  the 
movement  of  the  grooved  wheel  until  it  enters,  hanging  downwards,  the  compartment  b, 
containing  the  first  set  of  beaters.  By  the  time  the  flax  straw  has  been  carried  through  them, 
all  its  lower  half,  which  has  been  exposed  to  the  action  of  the  beaters,  is  cleaned  out,  and  the 
rope  passing  on  a  short  way  farther,  arrives  at  a  point  where  a  second  grooved  wheel  is  revolv- 
ing, furnished  with  ropes  in  like  manner,  but  arranged  at  a  rather  lower  level.  By  a  simple  ar- 
rangement, the  flax  is  here  transferred  from  one  set  of  ropes  to  the  other,  the  second  set  grasp- 
ing it  near  its  lowest  end,  thus  leaving  all  the  uncleaned  part,  or  upper  half  ready  to  be  scutched. 
The  second  wheel  moves  on  and  carries  the  flax  towards  the  compartment  containing  the  sec- 
ond set  of  beaters,  cleaning  all  the  upper  portion  of  the  flax.  It  then  issues  out  at  d,  cleaned 
throughout,  and  is  received  by  a  person  placed  there  for  that  purpose,  who  makes  it  up  into 
the  usual  package  for  sale,  IQ^  lbs.  A  constant  succession  of  similar  handfuls  of  flax  straw 
are  thus  kept  passing  tlirough  the  machine  without  interruption,  e  e  are  the  beaters,  f  f  are 
two  cones,  carrying  a  leather  band  which  gives  the  motion  to  the  ropes,  or  carrying  apparatus. 
By  shifting  the  position  of  this  band  towards  one  end  or  the  other  of  the  cones,  the  speed  of 
the  carrying  ropes  may  be  varied  at  pleasure,  so  as  to  keep  the  flax  a  longer  or  shorter  time 
under  the  beaters.  Some  kinds  of  flax  require  more  scutching  than  others,  g  g  are  the  driving 
pulleys,  for  giving  motion  to  the  machine,  by  means  of  a  band  from  motive  power,  which  may 
be  steam,  water,  wind,  or  horses.  Each  pair  of  pulleys  drives  one  set  of  beaters  separately 
from  the  other  set,  and  hence,  if  requisite  to  drive  one  set  faster  than  the  other,  which  is 
sometimes  the  case  when  the  top  end  of  the  flax  is  hard  to  clean,  this  is  easily  done  by  using 
a  similar  pulley  on  the  machine  or  a  larger  drum  on  the  driving  shaft,  h  »  are  tiie  tension 
weights  and  levers  for  keeping  tight  the  carrying  ropes,  j  j  are  bearers  of  wood  for  carry- 
ing the  frame  of  the  machine,  k  k  are  pits  underneath  the  compartments  containing  the 
beaters  and  are  for  receiving  the  woody  dust  as  it  falls  from  the  flax  straw.  The  maoliine 
occupies  a  space  of  11^  feet,  by  10  feet,  but  some  space  is  required  round  it  for  handling 
the  flax.     The  height  of  the  machine  is  6^  feet.     The  power  required  is  three-horse. 

M.  Mertens,  of  Gheel,  Belgium,  has  invented  a  scutching  machine,  which  merits  notice. 
It  is  portable  and  cheap,  and  requires  the  attendance  of  only  boys  or  girls,  to  put  the  flax 
straw  in,  and  take  the  scutched  fibre  out.  The  action  is  something  similar  to  that  of  the 
Irish  scutch-mill,  but  the  bruised  flax  straw  is  placed  in  iron  clasps,  one  end  being  first 
cleaned  out,  and  then  the  clasps  opened,  the  flax  straw  reversed,  and  a  second  insertion  in 
the  machine  clears  out  the  other  end. 

Messrs.  Rowan,  of  Belfast,  have  very  recently  introduced  a  scutching  machine,  whose 
action  differs  from  all  hitherto  in  use.  The  flax  straw  is  not  previously  bruised,  but  is  at 
once  fastened  in  iron  clasps,  which  are  placed  in  a  slide,  the  action  of  the  machine  carrying 
them  on  along  one  side,  wiiile  two  parallel  ijars  of  iron,  toothed,  comb  the  straw,  and  sep- 
arate the  woody  part  from  the  fibre.  The  first  portion  of  these  bars  have  coarse  teeth,  and 
the  teeth  become  closer  by  degrees  up  to  the  end  of  the  slide.  There  a  workman  or  boy 
takes  out  the  clasps,  unscrews  the  nuts  fastening  them,  and  reverses  the  position  of  the 
straw,  so  that  the  portion  not  previously  subjected  to  the  action  of  the  machine  is  now  pre- 
sented to  it,  while  that  already  cleaned  out  is  untouched.  The  machine  is  double,  i.  e.,  has 
two  sides  of  combs,  each  capable  of  containing  twelve  of  the  clasps,  and  each  cleaning  out 
one  end  of  the  flax  straw.  Hence  after  the  workman  or  boy  has  unclasped  the  half-cleaned 
straw,  turned  it  upside  down  and  presented  the  unclean  end  to  the  other  side  of  the  ma- 
chine, the  same  action  of  combing,  already  described,  clears  out  that  end  thoroughly,  and 
by  the  time  the  progressive  movement  of  the  mechanism  brings  the  slide  to  the  extreme 
end,  the  flax  fibre  appears  free  from  woody  refuse,  and  in  a  fit  state  for  market.  It  is  then 
unclasped,  and  made  up  into  bundles. 

There  have  been  a  great  number  of  other  scutching  machines  invented,  but  it  is  not 
necessary  to  particularize  them. 

In  the  operation  of  scutching,  however  carefully  it  may  be  done  by  hand  or  by  machine, 
there  occurs  more  or  less  waste;  /.  e.,  the  beating  of  the  flax  straw,  in  order  to  separate  the 
marketable  fibre  from  the  useless  wood,  causes  a  portion  of  the  former  to  be  torn  off  in 
short  filaments  mingled  with  the  wood,  and  this  torn  fibre  is  very  much  less  valuable  than 
the  long  filaments  when  finally  cleared  out.  In  general,  it  will  not  average  more  than  an 
eighth  or  a  tenth  of  the  value  of  the  long  fibre.  It  is  termed  scutch inci-tow  or  codilla,  and 
when  properly  cleaned  is  dry  spun  for  yarns  employed  in  making  coarse  sacking,  tarpaulins, 
&c.  Being  very  much  mixed  with  the  woody  matter  of  tlic  flax  stems,  it  is  necessary  to  get 
rid  of  the  latter  before  the  scutching-tow  can  be  spun  into  yarn.  To  acccTTnplish  this,  shak- 
ing by  hand  is  the  first  process,  and  subsequently  the  stuff  is  put  into  a  woody  machine 
tern^ed  a  "  devil,"  in  which,  by  a  mechanism  something  resembling  the  shakers  in  a  thresh- 
ing machine,  the  woody  particles  and  dust  are  got  rid  of  The  tow  is  sorted  into  different 
qualities,  and  in  some  cases  it  is  hackled  before  being  sold.     In  France  and  Belgium,  it  is 


544 


FLAX. 


chiefly  retained  at  home,  spun  by  band,  and  woven  into  such  fabrics  as  coarse  trowsers  and 
shirts,  for  the  laboring  classes,  aprons,  table-covers,  &c.,  &c.  AVhat  is  produced  in  Russia, 
is  partly  used  for  similar  purposes  among  the  serfs,  but  the  great  mass  is  exported.  Great 
Britain  and  Ireland  being  the  chief  mart,  and  Dundee  especially. 

The  great  aim,  iu  all  the  diflerent  methods  of  scutching,  has  been  to  obtain  the  largest 
possible  yield  of  long  fibre  from  the  flax  straw,  and  to  waste  as  little  as  possible  in  scutch- 
ing-tow.  The  French  and  Flemish  system  of  hand-scutching  is  most  successful  in  this 
respect,  but  as  the  quality  of  fibre  there  produced  is  very  much  finer,  and  consequently 
more  valuable  than  all  others,  the  additional  expense  of  hand  labor  is  compensated  by  the 
larger  yield  of  long  fibre  ;  whereas,  in  Ireland,  the  fibre  being  generally  coarser  and  less 
valuable,  occupying  an  intermediate  place  between  the  Flemish  and  Russian,  the  cheapness 
of  mill-scutching  turns  the  scale,  and,  except  in  remote  districts,  it  is  now  universal.  In 
Egypt,  until  some  fifteen  years  ago,  the  method  of  scutching  was  of  the  most  primitive 
form.  The  fellahs,  after  steeping  their  flax  in  the  Nile,  and  drying  it  on  the  banks,  pro- 
ceeded to  clean  out  the  fibre,  by  first  beating  the  straw  between  two  flat  stones,  and  then 
striking  it  against  a  wooden  post.  Sleheujet  Ali  and  his  successors,  however,  introduced 
Irish  scutch-mills,  driven  by  steam-power,  and  since  then  a  marked  improvement  has  taken 
place  in  the  state  in  which  Egyptian  flax  has  been  brought  to  market.  It  may  be  interest- 
ing to  note  here  that,  in  the  early  period  of  Egyptian  civilization,  the  dwellers  by  the  Nile 
were  able  to  manufacture  cambrics  of  a  finer  texture  than  the  most  finished  modern  me- 
chanism can  produce, — as  is  evidenced  by  the  cerecloths  wrapping  the  mummies,  and  that 
from  a  fibre  so  coarse  in  comparison  to  European  flax,  that  while  the  latter  may  be  spim  by 
machinery  to  3U0  or  400  leas,  and  by  hand  to  1200  leas,  the  former  cannot  be  put  higher 
than  40  to  50  leas,  and  rarely  even  to  that. 

In  the  scutching  operation,  three  several  matters  are  obtained  from  the  flax  stems.  The 
first  is  the  fibre,  which  is  the  primary  object,  and  which  is  the  really  valuable  portion,  that 
known  as  "  flax  "  in  commerce.  The  second  is  the  woody  refuse  of  the  stems,  hitherto 
applied  to  no  other  use  than  as  fuel,  or  occasionally  in  Ireland  as  a  covering  for  cuttings  of 
potatoes,  when  planted,  to  protect  them  from  frost.  Mr.  Pye,  of  Ipswich,  however,  pro- 
poses to  make  it  available  as  an  auxiliary  food  for  cattle,  having  the  authority  of  Professor 
Way  that  a  sample  analyzed  by  him  yielded  7*02  per  cent,  of  oil  and  fatty  matter;  793 
of  albuminous  matter,  (containing  1-25  nitrogen,)  and  26.29  starch,  gum,  sugar,  &c.  He 
(Mr.  Pye)  recommended  its  use  for  feeding  live  stock,  in  conjunction  with  ground  oats  or 
other  farinaceous  food.  Professor  Hodges,  nevertheless,  in  analyzing  another  sample  of 
this  ground  ligneous  matter,  gave  quite  a  different  result,  his  estimate  of  the  nutritive  con- 
stituents being  as  follows  : — nitrogenized  flesh-forming  matters,  3'23  percent. ;  oil  and  fatty 
matters,  2"91  ;  gum  and  soluble  matters,  14'66  ;  and  he  compared  this  with  the  average 
results  of  seven  analyses  of  oil  cake,  giving  nitrogenized  matters,  28.47 ;  fatty  matters, 
1290  ;  gum  and  other  soluble  matters,  39.01. 

The  third  portion  separated  by  the  scutching  process  is  termed  "  scutchincf-tou;"  in  Ire- 
land ;  in  Russia  and  Prussia,  "  codilla ; "  in  France  and  Belgium,  "  cfvuppe  de  teillagc,''^ 
described  above.  These  branches  of  the  trade  consume  annually  many  thousand  tons,  im- 
ported chiefly  into  Scotland,  from  Russia  and  Prussia.  In  France,  Belgium,  and  Holland, 
the  codilla  or  scutching-tow  is  chiefly  retained  by  the  growers  or  factors  at  home,  for  a  do- 
mestic manufacture  of  similar  goods,  and  of  coarse  blouses  and  trowscrs.  It  has  also  been 
employed  for  conversion,  by  Claussen's  process,  into  a  finely  divided  mass  of  fibres,  capable 
of  being  mixed  with  wool  and  spun  along  with  it  into  yarn,  the  fabric  made  from  this  yarn 
being  chiefly  hose. 

Before  proceeding  to  treat  of  the  processes  to  which  flax  fibre  is  subjected  subsequent 
to  scutching,  it  may  be  well  to  glance  at  the  uses  to  which  the  seed  is  applied.  This  val- 
uable product  of  the  plant  furnishes  two  -articles  of  much  utility,  and  of  very  extensive  use, 
— the  oil  and  the  cake.  When  the  seed  has  been  separated,  dried,  and  threshed  out,  it  is 
either  sold  again  for  sowing  or  for  conversion  into  cake  and  oil.  Of  course  the  former  pur- 
pose only  consumes  a  small  proportion  of  the  seed  produced  throughout  the  world,  and  in 
many  countries  it  is  not  of  a  quality  suitable  to  the  chief  flax-growing  localities.  Thus, 
while  Northern  Russia,  Germany,  the  Low  Countries,  and  France  either  export  seed  for 
sowing,  or  consume  their  own  produce  to  a  considerable  extent  for  this  purpose  ;  the  south- 
ern provinces  of  Russia,  the  states  along  the  Mediterranean,  Egypt,  Turkey,  Greece,  and  the 
East  Indies,  while  large  exporters  of  seed  for  crushing,  cannot  sell  any  for  sowing.  The 
supply  of  the  seed  crushers  of  the  United  Kingdom  is  more  largely  obtained  from  Russia 
and  Ilindoostan  than  from  any  other  countries.  The  entire  annual  import  of  seed  into  the 
British  Islands  averages  600,000  to  800,000  quarters,  value  between  a  million  and  a  half 
and  two  millions -sterling.  The  conversion  of  flax  seed  into  oil  and  cake  is  carried  out  by 
different  methods.  In  France,  Belgium,  Holland,  and  the  north  of  Europe  generally,  where 
a  large  quantity  is  crushed,  the  apparatus  employed  is  very  simple  and  yet  very  effective. 
Lille,  in  France,  Courtrai  and  Ghent,  in  Belgium,  Neuss,  in  Prussia,  and  the  province  of 
Holstein  are  the  great  seats  of  this  manufacture.     See  Linseed. 


FLAX. 


545 


The  seed  is  pounded  in  a  kind  of  wooden  mortars,  cut  out  of  solid  timber,  and  at  the  bottom 
lined  with  thicis  copper.  By  means  of  a  revolving  shaft,  furnished  with  projecting  notches 
of  wood,  beams  of  oak  20  feet  high,  the  ends  shod  with  channelled  iron,  are  alternately 
raised  up  and  let  fall  into  the  mortars,  where,  in  a  short  time,  they  convert  the  seed  into  a 
pulpy  mass.  When  sufficiently  pounded,  this  is  then  removed,  and  put  into  woollen  bags, 
which  are  then  wrapped  up  in  a  leathern  case  lined  with  a  hard-twisted  web  of  horsehair, 
covering  both  sides  and  ends,  but  open  at  the  edges.  These  are  then  ready  to  be  pressed, 
and  for  this  purpose  are  packed  perpendicularly  in  an  iron  receptacle,  narrow  at  the  bot- 
tom, and  widening  towards  the  top.  Packings  of  metal  are  then  put  in,  and  in  the  centre 
of  the  bags  is  inserted  a  beech  wedge.  A  beam  similar  to  that  employed  in  pounding  the 
seed  is  then  set  in  motion,  and  at  each  descending  stroke  it  drives  the  wedge  in  tighter, 
thus  squeezing  the  bags  of  seed  against  the  iron  sides  of  the  press.  When  the  wedge  has 
been  driven  home,  another  is  introduced  and  battered  by  the  beam,  until  it  will  drive  no 
farther.  At  the  bottom  of  the  press  are  holes  through  which  the  oil  thus  pressed  out  of  the 
seed  runs  into  a  receptacle  beneath.  In  order  to  loosen  the  wedges  and  admit  of  the  bags 
being  removed  from  the  press,  a  wedge  of  a  different  form,  wide  at  bottom  and  narrow  at 
top,  and  already  a  fixture  in  the  press,  but  raised  up  and  fastened  by  a  rope  during  the 
driving  of  the  other  wedges,  is  released  from  the  rope,  and  another  beam  drives  it  home, 
thus  partially  starting  the  differently  constructed  wedges  and  loosening  the  mass.  The  bags 
with  the  pressed  seed  are  then  taken  out,  and  the  latter,  having  lost  the  greater  part  of  its 
oil  while  subjected  to  so  considerable  a  pressure,  is  found  in  a  thin  hardish  cake,  taking  the 
form  of  the  leathern  case,  and  off  it  the  woollen  bag  is  readily  stripped  by  the  workman's 
hands.  The  oil  obtained  by  this  process  is  the  purest  and  most  limpid  ;  but  another  pro- 
cess has  to  be  performed  before  the  seed  yields  all  that  the  pressure  is  capable  of  extracting 
from  it.  The  cakes,  therefore,  when  taken  out  of  the  bags,  are  broken  up  and  put  into  the 
mortar,  where  the  same  pounding  operation  takes  place.  When  again  brought  into  a  com- 
minuted state,  the  powder  is  put  into  a  circular  iron  pan  or  kettle,  under  which  is  a  fire, 
and  slowly  roasted  in  it,  being  kept  from  burning  by  means  of  an  iron  arm  which  is  moved 
round  inside  by  the  machinery,  constantly  turning  the  ground  seed.  When  sufficiently 
warmed  by  this  operation,  during  which  it  is  made  to  part  more  freely  with  the  oil,  the 
mass  is  again  filled  in  bags  and  pressed  as  before,  after  which  they  are  finally,  the  bags 
being  stripped  off,  pared  at  the  edges,  put  in  a  rack  to  dry,  and  stored  for  sale.  The  oil 
thus  obtained  is  darker  in  color  than  that  by  the  cold  process,  and  contains  more  mucilag- 
inous matter.  Many  foreign  oil-millers,  however,  only  employ  the  hot  plan,  believing  that 
they  have  thus  a  larger  yield  than  when  the  cold  pressure  is  first  used. 

In  England,  the  cold  pressure  is  little,  if  at  all,  practised,  the  seed  being  almost  inva- 
riably warmed  before  pressure.  The  system  of  crushing,  formerly  universal  here,  had  some 
resemblance  to  the  Flemish  method  above  detailed,  the  chief  difference  being  in  the  mode 
of  preparing  the  seed,  prior  to  its  being  put  in  the  press.  The  first  process  is  to  pass  slowly 
from  a  hopper,  the  whole  seeds  into  a  pair  of  smooth  or  fluted  metal  rollers  which,  in  turn- 
ing on  each  other,  crack  the  seeds.  Heavy  edged  stones  then  grind  them  into  a  meal,  a 
little  water  being  added  during  the  operation,  which  facilitates  the  comminution  of  the  seed. 
The  meal  is  then  put  in  the  kettle  before  described,  and  while  heated  and  stirred  in  it,  the 
water  mixed  with  it  is  evaporated.  It  is  then  bagged  and  put  in  the  press,  where  the 
stampers,  falling  on  the  wedges,  effect  the  desired  results.  The  most  recent  improvement 
in  the  mode  of  pressure,  and  one  now  largely  adopted  is  the  hydraulic  press,  and  it  is  gen- 
erally considered  that  a  larger  yield  of  oil  can  be  obtained  by  its  use  than  by  the  wedge  and 
stamper-beam  method.  Blundell's  (of  Hull)  patent  is  that  most  generally  employed,  and 
Messrs.  Samuelson  of  tliat  place  are  distinguished  as  makers  of  it,  having  introduced  them- 
selves some  modifications  and  improvements.  The  oil  obtained  from  flaxseed  or  linseed,  as 
it  is  generally  termed,  is  of  very  extensive  use  in  the  arts,  and  is  the  chief  vehicle  for 
paints.  To  suit  it  for  this  purpose,  and  to  make  it  dry  quickly,  it  is  mostly  boiled  in  an 
iron  pan,  and  during  the  operation  a  quantity  of  litharge  is  dissolved  in  it.  The  cake  is  a 
very  favorite  article  with  stock-feeders,  being  combined,  as  containing  much  nutriment  in 
small  bulk,  with  roots  or  other  vegetable  food,  having  large  bulk  with  small  nutriment.  So 
extensively  is  it  consumed  in  Great  Britain,  that  besides  the  very  large  quantity  made  from 
imported  seed,  fully  80,000  tons  of  foreign  cake  are  annually  imported.  On  the  continent 
inferior  qualities  of  cake  are  ground  to  a  coarse  powder,  and  either  applied  to  the  soil  as  a 
top-dressing,  or  steeped  in  a  liquid  manure,  and  the  mass  spread  out  on  the  land  in  that  state. 

Scutched  flax  fibre  appears  in  the  market  made  up  in  different  ways.  Russian  is  in 
large  bales  or  bundles ;  Dutch  and  Flemish  in  bales  weighing  2  cwt.,  the  fibre  being  tied  in 
"  heads,"  each  of  which  is  about  as  much  as  the  hand  willl  grasp.  Irish  is  made  up  in  bun- 
•  dies  termed  "  stones,"  the  weight  of  which  is  either  16^^  lbs.  or  211  lbs.  In  this  state  it  is 
piled  in  the  stores  of  the  spinner,  care  being  taken  that  it  be  placed  on  a  ground-floor, 
flagged  or  tiled,  and  not  in  a  boarded  loft,  as  the  humid  atmosphere  of  the  former  is  con- 
ducive to  the  preservation  of  the  suppleness  and  "  spinning  quality  "  of  the  fibre,  whereas  it 
deterioriates  considerably  when  exposed  to  a  drier  air. 
Vol.  III.— 35 


546 


FLAX. 


The  first  operation  which  it  undergoes  in  tlie  spinning  factory  is  hackling. 

This  process  is  required  to  comb  and  straighten  the  tibrcs,  to  get  rid  of  any  knots,  and 
to  lessen  and  equahze  the  size  of  the  filaments.  The  action  of  the  hackles  necessarily 
divides  the  scutched  flax  into  two  portions,  the  long,  straight  ones,  which  remain  after  the 
flax  has  passed  through  the  operation,  being  termed  "  Ime,"  and  the  woolly  or  cottony- 
looking  mass  which  remains,  being  designated  "  tow."  Both  of  these  are  spun,  but  the  line 
produces  the  finer  and  better  qualities  of  yarn,  and  is  consequently  much  more  valuable 
than  the  tow.  The  great  object,  therefore,  is  to  obtain  the  largest  possible  quantity  of  the 
former  from  a  given  weight  of  scutched  flax,  and  the  yield  of  line  varies  considerably  ac- 
cording to  the  nature  of  the  season.  Spinners,  therefore,  are  anxious  as  each  new  crop  of 
flax  is  brought  to  a  marketable  state,  to  test  the  yield  of  line,  so  as  to  guide  them  in  their 
purchases.  They  are  thus  enabled  to  ascertain  more  clearly  the  suitability  of  the  samples 
for  "  warp  "  or  "  weft  "  yarns,  and  for  thread-twisting.  Warp-yarns  beirg  those  which  con- 
stitute the  long  threads  of  a  linen  fabric,  require  to  be  harder  and  stronger  than  weft-yarns, 
which  form  the  cross  or  short  threads. 

The  yield  of  line  as  well  as  the  general  economy  of  the  operation,  is,  of  course,  greatly 
dependent  on  the  nature  of  the  hackling  machine  employed,  and  great  scope  for  care  and 
ingenuity  is  thus  given  to  the  machine-makers.  A  great  number  of  hackling  machines  have, 
from  time  to  time,  been  brought  out,  employed  in  the  factories,  and  subsequently  aban- 
doned, when  others,  having  greater  merit,  have  been  invented. 

In  the  early  period  of  the  linen  manufacture,  when  spinning  was  done  exclusively  by 
hand,  no  hackling  machines  were  employed.    The  process  was  exclusively  effected  by  baud- 

303 


FLAX. 


547 


hackles.  Even  after  the  introduction  of  machine-spinning,  they  were,  for  a  long  period,  the 
sole  means  of  hackling.  Of  late  years,  the  machine  has  been  more  and  more  brought  into 
use,  and  although  hand-hackling  still  exists  to  a  considerable  extent,  the  other  method  is  by 
far  the  more  extensively  employed. 


A  machine  which  came  into  quite  extensive  use  was  Combe's  reversing  cylinders  fq. 
303.     These  macliiDcs  are  constructed  in  a  great  variety  of  forms  for  different  kinds'  of 


548 


FLAX. 


work,  and  seem  to  give  very  good  results.  They  are  simple  in  their  construction,  and  give 
little  trouble,  acting  lightly  on  the  flax  and  making  very  wiry  fibres.  They  are  made  of  all 
sizes  from  12  to  30  inches  in  diameter,  and  with  4,  6,  or  8  graduations  of  hackles,  accord- 
ing to  the  kind  of  work  to  be  done  on  them.  The  flax  is  hackled  on  each  side,  or  each  gra- 
duation of  hackles,  by  reversing  the  direction  of  the  rotation  of  cylinders.  The  tow,  or  short 
fibre,  is  thrown  ott"  the  hackles  by  stripper  rods,  placed  between  the  rows  of  pins. 

The  next  machine  to  be  named  is  by  the  same  inventor,  and  is  styled  the  patent  revers- 
ing sheet  hackling  machine.  It  is  for  long  line,  on  the  same  principle  as  that  just  de- 
scribed, except  that  it  has  the  hackles  fixed  on  flat  sheets,  as  in  the  "  old  flat "  machine. 
It  is  simple  and  complete  ;  easily  driven  and  attended,  and  a  considerable  number  are  now 
in  use.  From  the  hackles  being  on  a  flat  sheet,  it  is  necessary  to  make  the  holders  de- 
scend, first  on  one  side  while  the  sheets  are  moving  in  one  direction,  and  then  on  the  other 
while  they  are  moving  the  other  way.  This  is  done  by  supporting  the  channels  which  carry 
the  holders  on  four  levers  fixed  on  two  oscillating  shafts,  to  which  motion  is  communicated 
by  a  shaft.  The  holders  are  slid  through  by  a  lever  on  the  top,  which  acts  on  a  sliding  bar, 
by  means  of  a  ball,  which  forms  a  universal  joint  and  actuates  the  holders,  whatever  posi- 
tion the  channels  are  in.     The  drawing  here  given,  fg.  304,  will  show  the  mechanism. 

Both  the  machines  last  described  are  made  double,  or  in  fact,  the  construction  of  each 
is  that  of  two  machines  in  one.  The  table  for  filling  and  changing  the  flax  in  the  holders 
is  attached  to  the  machine.  One  side  hackles  one  end  of  the  flax,  and  the  other  side  the 
other  end. 

We  now  have  to  describe  a  machine  for  hackling  cut  line,  patented  by  Mr.  Lowry,  of 
Manchester,  and  now  extensively  in  use  at  home  and  on  the  continent.  It  is  virtually  a 
modification  of  Wordsworth's  machine,  already  described. 

Fig.  305  is  a  side  elevation  of  a  sheet  hackling  machine  to  which  these  improvements 

305 


are  applied  ;  fig.  306  is  an  end  elevation  of  the  same  ;  fg.  307  is  a  front  view  ;  and/?//.  308 
an  end  view  of  one  of  Lowry's  improved  hackle  bars.  In  fgs.  305,  306,  a  a  represent  the 
belts,  sheets,  or  chains  to  which  the  hackle  bars  b  are  attached.  These  belts,  sheets,  or 
chains  pass  around  the  small  drums  c  c,  and  larger  drums  d  </,  which  are  turned  round  by 
the  gearing,  shown  in  the  drawing,  or  by  any  other  suitable  arrangement  of  gearing.  The 
hackle  bars  b  are  made  with  a  recess  to  receive  the  stock  of  the  hackles  e. 

The  hackle  bars  b  are  connected  to  the  belts,  sheets,  or  chains  a  a,  by  means  of  rivets 
or  screws,  pa.ssing  through  the  flanges  b,  and  through  the  belts,  sheets,  or  chains  a  ;  and  at 
each  end  of  each  hackle  bar  is  a  stud  or  guide  pin  6",  which,  when  the  hackles  arrive  near 
the  small  drums  c  r,  take  into  the  groove  in  the  guide  plates.  The  object  of  these  guide 
plates  is  to  support  the  hackle  bars  in  passing  over  the  small  roUei'S  c,  and  during  the  oper- 
ation of  striking  into  the  strick  of  flax  or  other  filirous  material  to  be  operated  upon.  The 
holders  with  the  stricks  depending  from  them,  are  placed  within  the  rails  i  i,  and  these 


FLAX. 


549 


rails  are  made  to  rise  and  fall,  and  the  holders  are  made  to  pass  from  one  end  of  the  ma- 
chine to  the  other,  in  the  usual  manner.  When  the  machine  is  at  work  the  drums  c  and  d 
revolve  in  the  direction  of  the  arrows  in^^.  306,  and  the  hackle  bars  being  attached  to  the 
belts,  sheets,  or  chains  a,  and  supported  by  the  guide  plates,  cause  the  hackles  to  enter  the 


306 


307 


_y 

%   V 

> 

0 

308 
J 


stricks  of  fibrous  material  at  or  nearly  at  right  angles  to  the  fibres  thereof,  and  to  retain  that 
position  at  the  commencement  of  their  downward  motion ;  whereby  as  the  belts,  sheets, 
or  chains  continue  to  descend,  the  hackles  are  drawn  through  the  fibrous  material  for  the 
purpose  of  removing  the  short  fibres  and  extraneous  matter.  Another  great  advantage 
resulting  from  this  improved  mode  of  attaching  the  hackle  bars  b  to  the  belts,  sheets,  or 
chains  a,  is,  that  the  hackles  can  be  made  to  enter  the  fibrous  material  at  a  point  closer  to 
the  holder  than  in  any  of  the  sheet  machines  now  in  use.  When  the  hackles  are  passing 
round  the  drums  d  d,  they  are  cleansed  by  the  revolving  brushes  jj,  which  deposit  the  ma- 
terial removed  from  the  hackles  on  to  the  card  drums  k  k.  These  drums  are  cleansed  or 
doffed  by  the  combs  1 1,  or  in  any  other  convenient  manner. 

This  machine  is  also  used  to  a  very  large  extent,  and  well  liked  for  dressing  half  line 
and  full  length  flax.  For  this  purpose  the  sheets  require  to  be  made  six  inches  longer  from 
centre  to  centre,  and  the  head  or  trough  to  lift  3  inches  higher,  and  the  top  rollers  to  ap- 
proach and  recede  from  each  other  simultaneously  with  the  rising  and  falling  of  the  head. 

Combe,  of  Belfast,  has  recently  produced  another  edition  of  Wordsworth's  machine. 
Its  novel  feature  consists  in  dispensing  with  bars  altogether,  in  carrying  the  hackles  and  in 
fixing  them  directly  on  the  leather  sheets.  By  this  means  a  very  true  action  is  obtained, 
and  the  working  parts  are  so  light,  that  the  machine  bears  any  speed  with  scarcely  any 
wear  and  tear.  In  this  invention  there  are  also  combined  convenient  modes  of  regulating  the 
lift  and  severity  of  the  cutters  to  suit  different  kinds  of  flax,  and  the  holders  are  carried 
through  the  machine  by  a  separate  apparatus  for  that  purpose,  while  they  are  at  their  high- 
est elevation,  instead  of  during  the  whole  process  of  lifting,  as  had  always  been  the  case  in 
other  machines. 

A  machine  has  been  lately  invented,  and  brought  out  by  Sir  P.  Fairbairn  and  Co.,  of 
Leeds,  called  Heilmann's  tow-combing  machine,  {fir/.  309,)  which,  on  trial,  is  much  ap- 
proved of.  The  tow  is  first  carded  in  the  ordinary  way,  say  on  a  breaker  card,  and  then  on 
a  finisher  card  ;  the  latter  delivers  the  tow  in  the  shape  of  a  sliver  into  cans,  which  are  next 
placed  at  a,  or  back  of  the  tow-combing  machine. 

From  the  cans  a  the  tow  goes  to  the  back  conductor  b,  divided  into  as  many  compart- 
ments as  there  are  slivers ;  and  from  the  conductor  n,  to  the  feeding-box  c  suspended  on 
shaft  D,  without  being  keyed  to  it.  The  front  lip  e  of  the  feeding-box  is  fluted  and  fitted 
with  leather,  and  a  corresponding  nipper  f  hung  from  the  same  shaft  d,  and  keyed  upon  it, 
completes  the  jaw  which  has  to  hold  fast  the  tow,  while  the  cylinder  r.  combs  it. 

The  feeding-box  c  derives  its  motion  from  the  nipper  f,  which  is  moved  by  lever  and 
eccentric  as  shown,  and  follows  that  iiip|>cr  by  its  own  weight,  until  stopped  by  india-rubber 
buffers  ii ;  when  the  nipper  f  in  going  further  back  leaves  it,  and  the  jaw  e  f  opens  for 
more  tow  to  be  fed,  and  the  tow  already  combed  to  be  drawn  through  the  detaining  comb  i, 
as  explained  hereafter. 

The  top  K  of  feeding-box  is  movable  up  and  down,  by  means  of  the  connecting  rod  l, 


550 


FLAX. 


luing  on  a  fixed  centre  M,  so  that  the  top  part  K  opens  or  shuts  as  the  body  of  the  box  goes 
backwards  or  forwards.  The  levers  N  N  N  are  only  used  to  keep  the  top  and  bottom  of  the 
box  parallel  to  each  other. 

309 


As  shown  in  the  drawing,  the  top  of  the  feeding-box  is  fitted  with  hackles  passing 
through  two  grates  o  and  p,  fast  on  bottom  of  feeding-box,  and  leaving  between  them  a 
space  through  which  the  sliver  has  to  pass. 

By  the  above  arrangement,  the  hackles  are  caused  to  withdraw  from  the  tow,  while  the 
whole  box  is  drawn  backwards  on  slides  of  table  q,  by  the  eccentric  motion  r  r  r.  The 
last  backward  motion  takes  place  while  the  jaw  f  is  yet  shut,  and  the  top  of  the  box  up  ; 
but  when  the  latter  has  got  closed  again,  then  the  whole  box  slides  down  on  the  table  Q  to 
its  former  position,  bringing  with  it  the  sliver  of  a  quantity  equal  to  that  move  :  this  com- 
pletes the  feeding  motion. 

Now  as  the  feeding-box  recedes,  the  lip  e  comes  nearer  to  the  combing  cylinder  G,  the 
hackles  s  s  cleaning  tlie  tow  projecting  outside  the  nipper  f.  As  soon  as  they  are  passed 
through,  the  feeding-box  comes  back  to  the  most  forward  position,  when  the  nipper  f  leaves 
it,  and  the  jaw  e  f  opens  :  at  the  same  time  the  two  rollers  t  u  have  reached  their  top  posi- 
tion. The  top  one  t  is  then  thrown  forwards  (by  the  lever  arrangement  shown  in  v  v  v) 
upon  the  leather  w,  stretched  on  parts  of  surface  of  cylinder  g  ;  this  roller  t  is  thus  driven, 
and  takes  hold  of  the  points  of  the  tow  presented  to  it  by  lips  or  bottom  jaw  e  ;  a  fine  de- 
taining comb  I  being  just  before  interposed  between  them  to  keep  back  the  noils  that  have 
not  been  carried  off  by  the  combing  cylinder. 

In  that  way  the  points  of  the  tow  are  driven  upon  the  sheet  x,  until  the  roller  t,  by 
being  thrown  back  again  off  the  leather  w,  their  motion  is  stopped  at  the  same  moment,  the 
two  rollers  u  and  t  are  allowed  to  drop  .down  by  eccentric  v,  drawing  with  them  (through 
the  detaining  comb  i,  and  quite  out  of  the  rest  of  the  sliver)  the  other  ends  of  the  fibres  of 
which  they  have  got  hold. 

While  this  has  been  going  on,  the  feeding-box  has  advanced  the  sliver  a  step,  the  nip- 
per closed,  and  forced  the  said  feeding-box  forwards  so  as  to  bring  the  lip  e  within  the 
reach  of  hackles  s  on  cylinder  g,  which  then  met  it,  cleansed  the  tow,  and  so  on  as  before. 

At  that  time  the  rollers  t  and  u  come  up  again,  and  during  that  upward  motion  the  lat- 
ter ends  of  the  fibres  partly  combed  and  overturned  by  the  cylinder  hackles,  as  shown  in 
drawing,  are  combed  by  them  in  their  turn.  Then  the  roller  t  is  once  more  driven  round 
by  the  leather  w  stretched  on  cylinder,  the  new  points  place  themselves  above  tlie  back  ends 


FLY  POWDER. 


551 


of  the  fibres  combed  before,  and  are  carried  forwards  into  a  continuous  sliver  on  the  leather 
sheet  X,  from  the  leather  sheet  to  the  rollers  z  z,  then  to  the  trumpet  conductor  a,  the  front 
delivery  roller  c,  and  (when  more  than  one  head  to  the  machine)  from  c  to  the  end  delivery 
c,  over  the  conducting  plate  d. 

In  e,  /,  g,  and  A,  arc  the  usual  brusli,  doffer,  comb,  and  tow  box  for  the  noils. 

These  combing  machines  are  made  of  different  sizes  to  suit  all  sorts  and  lengths  of  tow ; 
the  yarn  produced  from  them  is  nmcli  finer  than  that  produced  by  the  ordinary  carding  sys- 
tem alone.  The  combed  tow  can  generally  be  spun  to  as  high  numbers  as  the  line  from 
which  it  has  been  combed,  and  in  some  instances  has  produced  good  yarn,  even  to  higher 
numbers.  The  combed  tow,  after  the  combing  machine,  is  passed  through  a  system  of 
drawing,  roving,  and  spinning,  similar  to  that  used  for  cut  line. 

310 


U=o 


Combe,  of  Belfast,  has  lately  introduced  an  improvement  in  the  roving  frame.  It  con- 
sists in  the  application  of  a  peculiar  expanding  pulley,  instead  of  the  cones  or  discs  and 
runners  which  have  hitherto  been  alwa3's  used  for  the  purpose  of  regulating  the  "  take-up  " 
of  the  bobbins.  It  is  evident  that  a  strop  of  2  or  3  in.  broad,  working  over  the  cones, 
placed  with  the  small  end  of  one  opposite  the  large  end  of  the  other,  is  an  imperfect  and 
rude  mechanical  contrivance,  and  that  there  must  be  a  constant  straining  and  stretching  of 
the  belts.  There  is  the  same  imperfection  attending  the  disc  and  runners.  The  expanding 
pulley  is  free  from  these  objections,  as  its  acting  surface  is  a  line,  and  therefore  it  works 
with  the  greatest  accuracy,  while  it  is  also  a  great  simplification  of  the  machine  generally. 
In  rovings  for  flax  and  tow  it  is  generally  driven  directly  from  the  front  roller,  by  which 
means  a  large  number  of  wheels  and  shafts  are  avoided. 

FLUVIATILE,  (Jluvius,  a  river,)  belonging  to  a  river. 

FLY  POWDER.  Under  this  name  they  sell  on  the  continent  the  black -colored  powder 
obtained  by  the  spontaneous  oxidizement  of  metallic  arsenic  in  the  air.  Various  prepara- 
tions of  white  arsenic  are  used  for  the  same  purpose  in  this  country.  King's  yellow  is  much 
used ;  it  should  be  made  by  boiling  together  sulphur,  lime,  and  white  arsenic,  but  much 
that  is  sold  is  merely  arsenic  and  sulphur  mixed. 

Objecting  on  principle  to  the  familiar  use  of  arsenic  and  dangerous  substances,  a  prefer- 
ence may  be  given  to  a  substitute  for  the  above,  made  by  boiling  quassia  chips  into  a  strong 
decoction  and  sweetening  with  loaf  sugar.     This  seems  to  have  deadly  power  over  the  flies. 


552  FOUNDING. 

who  can  scarcely  quit  the  liquid  without  imbibing  a  deadly  potion,  and  they  are  seen  to  fall 
from  the  ceilings  and  walls  of  the  rooms  soon  afterwards.  Many  of  these  compounds  for 
killing  flies  are  supposed  by  their  odor  to  attract  flies  into  the  rooms. 

The  inconvenience  to  manufacturers  and  others  from  flies,  may  be  obviated  in  many 
cases  where  apartments  are  required  to  be  kept  as  free  as  possible  from  them,  by  reference 
to  facts  recorded  by  Herodotus,  of  fishermen  surrounding  themselves  with  their  nets  to 
keep  off  the  gnats.  We  are  indebted  to  William  Spence,  Esq.,  F.R.S.,  for  some  very  curi- 
ous particulars  respecting  the  common  house  fly  communicated  in  a  paper  to  the  Entomo- 
logical Society.  The  common  house  fly  will  not  in  general  pass  through  the  meshes  of  a 
net.  The  inhabitants  of  Florence  and  other  parts  of  Italy  are  aware  of  this  fact,  and  pro- 
tect their  apartments  by  hanging  network  up  at  the  windows,  thus  at  all  times  the  doors  and 
windows  may  be  kept  wide  open  by  hanging  a  light  network  over  the  aperture ;  the  meshes 
may  be  of  considerable  width,  say  enough  for  several  flies  on  the  wing  to  pass  through,  and 
no  fly  will  attempt  to  pass,  unless  there  be  a  strong  light,  (another  window  opposite,  or  re- 
flection from  a  looking-glass.)  A  knowledge  of  this  simple  means  of  protection  from  flies 
on  the  wing  may  prevent  inconvenience  from  these  intruders,  and  obviate  the  necessity  for 
poisons  to  destroy  them. — T.  J.  P. 

FOUNDING.  In  foundries  attached  to  blast-furnaces,  where  from  20  to  30  tons  of  iron 
are  made  pfr  diem,  the  moulds  are  generally  mere  troughs  cut  in  the  sand  in  which  the 
melted  metal  flows  and  cools  in  contact  with  the  air.  The  surfaces  of  the  castings  made  in 
this  manner  present  appearances  which  vary  according  to  the  quality  of  the  iron. 

The  kinds  of  iron  adapted  for  founding  purposes  are  those  which  are  most  fluid  when 
melted,  and  which  contain  most  carbon,  and  are  called  Nos.  1  and  2.  They  are  distin- 
guished by  the  surface  of  the  pig  of  iron,  which  was  exposed  to  the  air  during  cooling,  being 
smooth,  and  presenting  a  slightly  convex  figure.  The  surfaces  of  Nos.  3  and  4  pig  iron,  and 
of  the  white  crystalline  pig  iron  (most  suitable  for  making  into  wrought  iron)  present  a 
concave  figure,  and  the  surfaces  are  very  irregular  and  pitted  with  holes.  The  color  of  the 
fracture,  and  the  closeness  of  the  grain,  also  indicate  the  proportion  of  carbon  in  pig  iron. 

The  mixtures  of  metal,  melting  temperatures  of  metal,  &c.,  require  the  closest  observa- 
tion on  the  part  of  the  workmen  and '  foremen  who  practise  iron  founding,  and  these  me- 
chanics are  in  the  practice  of  observing  diflerences  so  minute  that  they  cannot  be  appre- 
ciated by  the  chemist,  or  expressed  in  words. 

Machinery  has  enabled  the  modern  founder,  by  means  of  railways,  turn-tables,  travelling 
cranes,  and  steam-power,  to  move  at  will  the  heaviest  masses  without  confusion  and  with 
great  expedition ;  but  nothing  but  the  traditions  of  the  factory,  and  the  constant  habit  of 
observation  will  enable  him  to  conduct  properly  the  melting  and  casting  of  metal  so  as  to 
an-ive  at  certain  results. 

This  is  proved  by  the  constant  failures  of  those  who  undertake  to  make  descriptions  of 
castings,  of  which  they  have  had  no  previous  knowledge. 

Each  branch  of  foundry  work  must  be  studied  in  detail,  and  we  can  only  pretend  to  indi- 
cate those  directions  in  which  progress  has  been  and  is  being  made. 

Foundry. — The  process  of  iron  smelting  and  the  construction  of  furnaces  having  been 
described  under  other  heads,  the  remaining  part  of  the  business  of  a  foundry,  viz.,  that 
which  relates  to  the  preparation  of  the  moulds  and  moulding,  will  now  be  described. 

ifouldinf). — The  art  of  moulding  is  one  of  the  most  important  processes  carried  on  in  a 
foundry,  and  the  success  of  the  founder  is  directly  proportioned  to  the  skill  and  ingenuity 
brought  to  bear  upon  the  production  of  the  patterns  and  the  system  of  moulding. 

Before  metals  can  be  cast  into  the  variety  of  shapes  in  which  they  are  wanted,  patterns 
must  be  prepared  of  wood  or  metal,  and  then  moulds  constructed  of  some  sufficiently  infu- 
sible material  capable  of  receiving  the  fluid  metal,  and  retaining  it  without  uniting  with  it 
until  it  has  solidified. 

A  mixture  of  sand  and  loam  (packed  tightly  into  metal  boxes,  called  flasks)  is  genially 
chosen  as  the  material  for  making  moulds,  and  is  employed  advantageously  for  seveial  im- 
portant reasons. 

Flasks. — In  modern  foundries  a  system  has  been  invented,  by  which  flasksof  any  dimen- 
sions may  be  constructed  by  means  of  bolting  together  a  number  of  rectangular  frames  of 
cast-iron,  so  arranged  as  to  admit  of  being  easily  connected  together. 

When  the  particular  castings  for  which  the  flask  has  been  constructed,  or  rather  com- 
pounded, are  completed,  the  separate  pieces  are  unbolted,  and  are  ready  to  be  combined  in 
some  new  form  appropriate  to  the  dimensions  of  the  pattern  next  to  be  moulded  in  them. 

The  loss  of  capital,  &c.,  invested  in  flasks,  only  occasionally  used,  is  thus  saved,  as  well 
as  loss  of  time  in  .searching  for  the  size  req\iired.  The  space  devoted,  on  the  old  system,  to 
the  reception  of  flasks  belonging  to  a  foundry  was  very  large,  and  this  may  now  be  appro- 
priated to  other  purposes. 

Sand  and  loam. — Founders  formerly  used,  on  account  of  price,  the  description  of  sand 
most  accessible  to  them,  but  at  the  present  time  the  convenience  and  cheapness  of  railway 
carriage  have  enabled  special  qualities  of  sand  to  be  delivered  to  all  parts  of  England. 


FOUNDING.  553 

For  founding  purposes  sand  is  much  improved  by  the  admixture  of  coke,  crushed  and 
reduced  to  a  fine  powder,  and  a  mill  for  this  purpose  is  as  necessary  in  every  large  foundry 
as  those  for  grinding  and  mixing  loam. 

Moulding  sand  must  be  a  mixture  of  a  large  quantity  of  silex  and  a  small  quantity  of 
alumina — the  property  of  the  latter  material  being  to  cement  the  grains  of  silex  together. 
Loam  consists  of  the  same  materials  mingled  in  opposite  proportions. 

The  preparation  of  loam  for  those  purposes  for  which  sand  is  not  adapted,  is  an  impor- 
tant duty  in  a  foundry,  for  a  great  quantity  of  loam  cores  have  to  be  made  and  dried  in 
proper  ovens,  which  is  a  tedious  operation. 

Many  castings,  such  as  the  screws  for  steamers,  are  more  conveniently  cast  in  moulds 
constructed  of  wet  loam.  These  are  shaped  to  the  required  form  when  the  clay  is  moist, 
and  then  carefully  dried  afterwards. 

Other  castings  are  of  such  peculiar  shapes  that  they  can  only  be  produced  in  moulds  that 
take  in  a  vast  number  of  pieces.  These  moulds  are  then  formed  of  a  number  of  pieces  of 
hardened  sand,  held  together  by  strips  of  iron  or  of  plaster,  if  the  sand  used  is  not  coherent 
enough  of  itself. 

Compounds  of  silex  and  alumina  arc  very  infusible,  and  when  moistened  with  water  and 
faced  with  carbonaceous  matter,  they  arc  capable  of  receiving  the  most  delicate  impressions 
from  the  patterns  which  the  founder  employs. 

Grains  of  sand  are  so  iflln^gular  in  shape  themselves  that  they  leave  innumerable  irreg- 
ular spaces  between  them,  and  these  intervals  form  a  network  of  channels  which  permit 
the  rapid  escape  of  the  gases,  which  are  so  violently  generated  by  the  contact  of  hot  metal 
falling  upon  wet  sand. 

Machine  Castings. — Every  year,  engineers  order  castings  to  be  prepared  of  more  diffi- 
cult and  complicated  forms,  and  with  greater  perfection  of  surface  than  they  have  required 
before. 

The  reason  of  this  is,  that  with  the  progress  of  the  mechanical  arts,  larger  and  stronger 
machines  are  continually  being  introduced.  In  these  machines  greater  steadiness  of  cast- 
iron  framework  is  necessary,  than  can  conveniently  be  obtained  when  the  frame  is  made 
out  of  a  number  of  pieces  of  iron  cast  separately  and  then  bolted  together.  It  would  bo 
impossible  to  mould  large  frames  with  pieces  projecting  on  all  sides,  (prepared  to  receive  the 
moving  parts  of  the  machines,)  and  jutting  out  in  contiary  directions,  in  any  flasks  filled 
with  wet  sand,  for  the  pattern  never  could  be  removed  without  destroying  the  impression. 
To  meet  these  difficulties  the  modern  iron  founder  has  had  to  follow  those  plans  which  were 
first  proved  practicable  by  those  who  have  devoted  themselves  to  casting  bronze  statues. 
In  founding,  as  in  so  many  other  branches  of  manufacture,  the  discoveries  made  in  prose- 
cuting the  fine  arts  have  been  advantageously  adopted  by  those  engaged  in  works  of  utility. 

False  Cores. — The  introduction  of  the  drawbacks,  or  false  cores,  made  of  sand  pressed 
hard,  (and  admitting  of  taking  to  pieces  by  joints,  at  each  of  which  a  layer  of  parting  sand 
is  prepared,)  used  for  figure  casting,  enables  the  moulder  to  work  at  his  leisure,  without 
fearing  that  his  mould  may  tumble  to  pieces,  and  also  enables  him  to  fashion  these  draw- 
backs or  cores  into  the  most  complicated  forms,  with  the  power  to  remove  them  while  the 
pattern  is  removed,  and  build  them  up  again  round  the  empty  space  (formerly  occupied  by 
the  pattern)  with  the  greatest  facility  and  accuracy. 

The  woi-kmen  whose  occupation  is  to  knead  the  sand  into  the  forms  required  by  the 
founder,  are  termed  moulders,  and  they  form  a  very  numerous  body  of  mechanics,  de- 
manding and  receiving  high  wages. 

The  moulder  has  often  only  his  sand,  his  flasks,  cranes,  and  a  few  simple  tools,  (for 
smoothing  rough  places,  and  for  repairing  the  places  in  the  sand,  where  the  mould  has 
broken  away  during  the  lifting  of  the  pattern;)  he  has  to  make  proper  arrangements  for 
the  exit  of  the  atmospheric  air  which  leaves  the  mould  as  the  fluid  metal  takes  its  place ; 
and  he  is  expected  to  produce  an  exact  copy  in  metal  from  any  pattern,  simple  or  conii)li- 
cated,  which  may  be  brought  before  liim. 

It  will  be  evident  that  to  produce  a  good  result  with  such  imperfect  appliances  as  the 
ordinary  moulder  uses,  a  skilful  workman  must  be  employed,  and  time  expended  in  pro- 
portion to  the  difficulty  of  the  operations  to  be  performed. 

Where  only  a  few  impressions  from  a  model  are  required,  it  is  not  worth  while  to  spend 
money  in  making  expensive  patterns,  or  providing  those'appliances  which  may  enable  pat- 
terns to  be  moulded  with  facility  and  little  skill;  but  where  thousands  of  castings  are 
wanted  of  one  shape,  it  is  expedient  to  spend  money  and  skill  on  patterns  and  tools,  and 
reduce  the  work  of  the  moulder  to  its  minimum. 

Management. — The  best  managed  foundry  is  not  that  in  which  good  eastings  are 
obtained  by  the  employment  of  skilled  workmen  at  a  great  expense,  and  without  trouble  or 
thouglit  on  the  part  of  tlie  principal,  ))ut  rather  that  in  which  the  patterns  have  been  con- 
structed with  a  special  reference  to  their  licing  cast  with  the  minimum  of  skill  and  (he 
maximum  of  accuracy.  It  is  only  by  the  forethought  and  calculation  of  the  manager  that 
subsequent  operations  can  be  reduced  to  their  smallest  cost ;   and  in  the  foundry,  as  in  all 


554 


FOUNDING. 


other  manufactorieg,  the  true  principles  of  economy  are  only  practised  where  the  head 
work  of  one  person  saves  the  manual  labor  of  a  large  number. 

Improvements. — The  attention  of  founders  has  been  turned — 1st,  to  the  methods  by 
which  the  labor  of  making  moulds  in  sand  might  be  reduced ;  2d,  to  the  introduction  of 
improvements  in  the  mode  of  constructing  patterns  and  moulds ;  and  Sd,  to  the  manufacture 
of  metallic  moulds  for  those  purposes  for  which  they  could  be  applied.  A  great  progress 
has  been  made  during  the  last  twenty  years  in  these  dilfercnt  directions. 

Machine  Moulding. — In  the  large  industry  carried  on  for  the  production  of  cast-iron 
pipes  for  the  conveyance  of  water  and  gas,  machinery  has  been  applied  so  that  the 
operation  of  pipe-moulding  is  performed  almost  without  manual  labor,  with  great  rapidity 
and  precision.  The  co.-<t  of  jiipes  at  the  present  time  is  only  about  11.  per  ton  above  the 
value  of  pig  iron,  out  of  which  they  are  made — a  sum  very  small  when  it  is  considered 
that  the  iron  has  to  be  remclted,  an  operation  involving  both  a  cost  of  fuel  and  a  loss  of  5 
to  20  per  cent,  of  the  iron  in  the  cupola.  An  ingenious  machine  for  moulding  in  sand 
spur  and  bevel  wheels  of  any  pitch  or  diameter  has  been  employed  in  Lancashire;  the 
advantage  being  that  the  machine  moulding-tool  acts  directly  upon  the  sand  without  the 
intervention  of  any  pattern  or  mould.  In  any  large  foundry  there  is  an  enormous  accumu- 
lation of  costly  wheel-patterns,  taking  up  a  great  deal  of  space,  and  these  can  now  be  dis- 
pensed with  by  substituting  the  wheel  moulding-machine.  Hallway  chairs  are  moulded  in  a 
machine ;  and  ploughshares,  which,  although  only  weighing  a  ig\y  pounds  each,  are  sold  at 
the  low  rate  of  8/.  a  ton,  are  moulded  in  a  machine. 

Plate  Casting. — Under  the  next  class  of  improvements  the  introduction  of  plate-casting 
has  been  the  most  fruitful  of  good  results. 

One  great  source  of  expense  and  trouble  in  a  foundry  is  the  injury  done  to  patterns  and 
to  tlieir  impressions  in  the  sand  by  the  necessity,  under  the  ordinary  system  of  moulding, 
of  striking  the  pattern,  or  pushing  it  first  in  one  direction  and  then  in  another  in  order  to 
loosen  it.  Now,  the  object  of  the  machinist  is  to  construct  all  his  spindles,  bearings,  bolts, 
and  wheels,  of  specified  sizes,  and  then  to  cast  the  framing  of  his  machine  so  accurately 
that  the  working  parts  may  fit  into  the  frame  without  any  manual  labor.  In  order  to  effect 
this,  every  projection  and  every  aperture  in  the  casting  must  be  at  an  exact  distance,  and 
this  can  only  be  attained  by  employing  such  a  system  as  that  of  plate-casting,  where  the 
pattern  is  attached  firmly  to  a  plate,  and  it  is  impossible  for  the  moulder  to  distort  or  injure 
the  impression.  Plate-casting  has  been  long  known,  but  was  practically  confined  for  many 
years  to  the  production  of  small  articles,  such  as  cast  nails  and  rivets. 

In  a  plate-mould  for  rivet-casting,  the  shafts  of  the  rivets  are  attached  to  one  side  of  the 
plate,  which  is  f  in.  thick,  and  planed  on  both  sides.  The  heads  of  the  rivets  are  on  the 
opposite  side  of  the  plate.  The  guides  on  the  upper  and  lower  flask  admit  the  plate  to  fit 
between  them,  and  when  the  plate  is  withdrawn  the  upper  and  lower  flask  close  perfectly, 
and  are  in  all  respects  like  ordinary  moulders'  flasks.  The  principle  of  moulding  is  very 
simple,  and  can  be  performed  without  skilled  labor  ten  times  as  fast  as  ordinary  moulding, 

311 


A,  sand. 


B  B,  flask. 


K  K,  rivet  pattoru. 


r,  plate 


and  with  far  greater  accuracy.  The  plate  is  inserted  between  the  upper  and  lower  flasks, 
and  sand  is  filled  in ;  the  plate  is  then  withdrawn  by  simply  lifting  it ;  the  guides  prevent 
any  shaking  in  this  operation ;  when  the  flasks  are  closed  the  impression  of  the  head  of 
each  rivet  is  exactly  perpendicular  to  its  shaft.  The  first  expense  of  patterns  and  plates  of 
this  description  is  large,  but  the  accuracy  and  rapidity  of  the  process  of  moulding  is  so 
advantageous  as  to  cause  us  to  look  to  the  applications  of  plate-castings  becoming  very  ex- 
tensive, since  the  requirements  of  the  machine-maker  demand  every  year  better  castings  at 
lower  prices. 

When  both  sides  of  a  pattern  are  .symmetrical,  one-half  only  need  be  attached  to  the 
Bmooth  plate,  the  other  face  of  the  plate  being  left  blank.     An  impression  of  the  pattern 


FOUNDING.  555 

must  be  taken  off,  both  in  the  upper  and  lower  flask,  and  when  these  are  united  the  result 
will  be  the  same  as  if  both  sides  of  the  plate  had  been  moulded  from.  For  unsymmetrical 
patterns  both  sides  of  the  plate  must  be  employed.  The  system  of  using  plates  wilh 
apertures  in  them,  through  which  patterns  could  be  pushed  and  withdrawn  by  means  of  a 
lever,  was  first  employed  in  casting  brass  nails.  A  modification  of  this  system  has  been  ex- 
tensively employed  at  Woolwich  for  moulding  shot  and  shells,  in  the  following  manner: 

Shell  Cast'mg. — A  circular  aperture  is  made  in  a  horizontal  planed  plate  of  iron,  two 
inches  thick.  Through  this  a  sphere  of  iron,  of  the  same  diameter  as  the  aperture,  is 
pushed  until  exactly  a  hemisphere  appears  above  the  plate.  The  lower  flask  is  put  on  to 
the  plate,  and  sand' filled  in;  the  lever  being  relieved,  the  sphere  falls  by  its  own  weight; 
the  lower  flask  is  removed  and  the  upper  flask  put  on  the  plate ;  the  sphere  is  pushed 
through  the  plate  as  before,  sand  filled  in,  with  great  rapidity  and  accuracy. 

The  sand  cores  for  filling  up  that  part  of  the  shell  which  is  to  be  hollow  are  also  care- 
fully and  quickly  made  at  Woolwich.  The  halves  of  the  core-mould  open  and  shut  with  a 
lever,  so  that  the  bad  plan  of  striking  the  core-mould  is  avoided  as  completely  as  the  bad 
plan  of  striking  the  pattern  is  in  the  process  of  moulding  shot  and  shell. 

Thcorti  of  Casting. — Before  leaving  the  subject  of  the  use  of  sand  moulds,  we  may 
remark  that  iron  and  brass  castings  with  a  perfect  surface  can  only  be  produced  when  the 
mould  is  well  dried  and  heated,  so  as  to  drive  out  any  moisture  from  the  apertures  between 
the  grains  of  sand.  By  this  means  channels  are  opened  for  the  rapid  escape  of  the  heated 
air  and  gas  expelled  by  the  entrance  of  the  fluid  metal  into  the  mould,  and  the  surface  of 
the  metal  is  not  cooled  by  its  contact  with  damp  or  cold  sand.  It  is  also  well  to  mix  char- 
coal dust,  or  coke  dust,  with  the  sand ;  and  for  fine  castings  to  cover  the  surface  of  the 
sand  with  a  coating  of  charcoal  dust.  The  object  of  this  proceeding  is  to  reduce  the  oxide 
which  may  be  present  in  the  metal.  This  operation  of  reducing  the  oxide  of  a  metal 
instantaneously  is  performed  with  the  greatest  certainty  by  this  simple  means,  invented, 
probably,  by  the  earliest  metallurgists.  By  incorporating  a  quantity  of  charcoal  or  coke 
dust  with  the  sand,  or  facing  the  sand  with  carbonaceous  matter,  any  oxide  of  the  metal 
which  may  be  floating  amongst  the  pure  metal  is  at  once  reduced.  Sand  (being  a  non- 
conductor) does  not  abstract  the  heat  from  the  fluid  metal  rapidly,  and,  therefore,  solidifi- 
cation of  the  metal  takes  place  comparatively  regularly  and  equally  throughout  the  mass ; 
when  one  part  of  the  casting  solidifies  before  the  adjoining  part,  flaws  often  occur,  and  to 
avoid  these  the  skill  of  the  practical  founder  is  necessary  in  arranging  for  the  entrance  of 
the  metal  at  the  proper  point,  and  for  the  exit  of  the  air. 

We  next  proceed  to  the  third  class  of  improvements  in  moulding,  that  of  the  extension 
of  the  application  of  metallic  moulds. 

Metal  3Ioulds. — The  practice  of  casting  bronze  weapons  in  moulds  made  of  bronze 
(blackened  over  on  their  surface  to  prevent  the  fluid  metal  uniting  with  the  mould)  appears 
to  have  been  a  very  general  one  among  the  ancients. 

Some  moulds  of  this  description  have  been  discovered  amongst  the  Celtic  (?)  remains 
disinterred  in  different  parts  of  Europe. 

The  facility  for  the  escape  of  the  heated  air  and  gases  from  the  sand  moulds  into  which 
liquid  metal  is  poured,  is  so  much  greater  than  that  from  moulds  of  metal,  that  at  the 
present  time  neither  brass  nor  iron  is  poured  into  metallic  moulds,  except  when  a  particular 
purpose  is  to  be  attained,  viz.,  that  of  chilling  the  surfiice  of  the  iron  and  making  it  as  hard 
as  steel.     Iron  cannot  be  chilled  or  hardened  in  a  sand  mould. 

Chilled  Iron. — This  process  of  casting  in  metal  moulds  was  once  supposed  to  be  a 
modern  invention ;  but  it  now  appears,  from  the  metal  moulds  discovered  among  the  re- 
mains of  the  Celtic  race  throughout  Europe,  that  the  bronze  weapons  of  the  people  who 
preceded  the  Romans  were  generally  cast  in  metallic  moulds,  and  not  in  sand.  Chilled 
castings  have  been  brought  to  great  perfection  by  Messrs.  Ransome,  of  Ipswich.  Their 
chilled  ploughshares  and  chilled  railway  chairs  are  cast  in  moulds  of  such  a  construction 
that  the  melted  iron  comes  in  contact  with  iron  in  those  parts  of  the  moulds  where  it  is 
wanted  to  be  chilled.     A  section  of  the  casting  shows  the  cff'ect  of  chilling. 

Zinc. — In  casting  zinc,  (a  cheap  and  abundant  metal,)  which  fuses  at  a  low  temperature, 
metallic  moulds  may  be  most  advantageously  used.  It  is,  however,  necessary  to  heat  the 
iron  or  brass  mould  nearly  to  the  temperature  of  melting  zinc,  in  order  that  the  rapid  ab- 
straction of  heat  from  the  fluid  metal  may  be  prevented.  The  preparation  of  metal  moulds, 
and  the  castiug  soft  metal  in  them,  is  now  an  extensive  and  important  industry  on  the 
continent,  for  ornamental  zinc  castings  have  suddenly  come  into  extensive  use  in  con.se- 
quence  of  the  discovery  of  the  electrotyping  process.  When  covered  with  a  thin  coating 
of  brass  or  copper  by  a  galvanic  battery,  zinc  may  be  bronzed  so  as  to  present  almost  the 
.exact  external  appearances  of  real  bronze  at  a  tenth  of  the  cost. 

When  metal  moulds  are  used  their  first  cost  is  very  gredt,  as  they  must  be  made  in 
numerous  separate  pieces  so  as  to  liberate  the  castings.  The  joints  and  ornaments  have  to 
be  chased  and  accurately  fitted  at  a  groat  expense.  Their  use,  however,  rcf(uiresno  skill  in 
the  workman,  and  the  rapidity  with  which  the  zinc  is  cast,  the  mould  taken  to  pieces,  and 
the  casting  removed,  renders  the  operaticm  a  very  rapid  and  economical  one. — A.  T. 


556  FRANKLmiTE. 

FRANKLINITE.  A  somewhat  remarkable  mineral,  whicli  is  found  at  Hamburg,  N.  J., 
with  red  oxide  of  zinc  and  garnet  in  granular  limestone.  Its  composition  has  been  de- 
termined to  be — 


1. 

2. 

3. 

Oxide  of  iron 

-     66-0 

•     68-88 

66-12 

Oxide  of  manganese 

-     18-0 

18-17 

■     11-19 

Oxide  of  zinc 

-     17-0 

10-81 

21-77 

Franklinite  was  at  first  employed  for  the  production  of  zinc ;  but  for  that  purpose  it  did 
not  answer  commercially.  It  is,  however,  now  employed  in  combination  with  iron,  as  it  is 
said,  with  much  advantage.  Major  Farrington,  of  New  Jersey,  thus  speaks  of  it:  "  Many 
experiments  have  been  made  under  my  superintendence  upon  the  ores  of  Franklinite,  and 
I  have  also  witnessed  several  others  of  an  interesting  character  made  by  other  parties  in 
mixing  Franklinite  with  pig  iron  in  the  puddling-furnace,  and  also  a  mixture  of  Franklinite 
pig  with  other  irons  in  their  conversion  to  wrought  iron.  The  result  in  all  cases  has  been 
a  great  improvement  in  the  quality  of  iron  as  manufactured.  The  most  marked  and,  as  I 
consider,  the  most  valuable  result  is  obtained  by  using  from  10  to  15  percent,  of  the  weight 
of  pig  iron  to  be  puddled  with  pulverized  Franklinite  ore  in  the  furnace  at  each  heat.  Iron 
of  the  most  inferior  quality,  when  thus  treated,  is  converted  into  an  article  of  No.  1  grade. 
The  volatile  nature  of  zinc  at  a  high  temperature,  combining  with  the  sulphur,  phosphorus, 
and  other  volatile  constituents  of  the  coal,  or  that  may  be  in  the  iron,  being  carried  off 
mechanically,  I  consider  is  one  of  the  causes  of  the  improvement ;  the  manganese  also  of 
the  ore  combines  with  silica  at  a  high  temperature,  and  pig  iron  that  contains  silica  is  thus 
freed  from  it.  The  great  advantage  to  be  obtained  by  using  the  pulvciized  ore  in  the 
puddling-furnace  is,  that  a  high  grade  of  iron  may  be  made ;  and  where  reheating  has  been 
hitherto  deemed  indispensable,  one  heating  is  found  sufficient  for  such  uses  as  wire  billets, 
nuts,  bolts,  horseshoe  iron,  and  nails.  A  particular  selection  of  fuel  is  not  required — coke 
and  charcoal  can  be  dispensed  with,  and  bituminous  or  anthracite  coal  used." 

FREEZING.  The  most  intense  cold  that  is  as  yet  known  is  that  from  the  evaporation 
of  a  mixture  of  solid  carbonic  acid  and  sulphuric  ether,  by  which  a  temperature  of  166° 
Falir.  below  the  freezing  point  of  water  is  produced.  By  means  of  tliis  intense  cold, 
assisted  by  mechanical  pressure,  several  of  the  gaseous  bodies  have  been  condensed  into 
liquids,  and  in  some  instances  solidified. 

Sir  John  Herschel,  some  years  since,  recommended  the  following  method  for  obtaining 
at  moderate  cost  large  quantities  of  ice  : 

A  steam  engine  boiler  was  to  be  sunk  into  the  earth,  and  the  quantity  of  water  which  it 
was  desired  to  freeze  placed  in  it.  By  means  of  a  condensing  pump,  several  atmospheres 
of  air  were  forced  into  the  boiler,  and  then  every  thing  was  allowed  to  remain  for  a  night, 
or  until  the  whole  had  acquired  the  temperature  of  the  surrounding  earth.  Then,  by  open- 
ing a  stopcock,  the  air,  expanding,  escaped  with  much  violence,  and  the  water  being  robbed 
of  its  heat  to  supply  the  expanding  air,  the  temperature  of  the  whole  was  so  reduced  that  a 
mass  of  ice  was  the  result. 

The  following  process  for  producing  cold  has  been  patented  and  exhibited  in  this  country : 

In  a  reservoir,  or  what  may  with  propriety  be  called  a  boiler,  was  placed  a  quantity  of 
sulphuric  ether.  This  reservoir  was  placed  in  a  long  vessel  of  saline  water,  this  fluid  by 
the  arrangement  being  made  to  flow  from  one  end  of  the  trough  to  the  other,  that  is,  to 
and  from  the  reservoir.  In  this  water  was  jilaced  a  number  of  vessels,  the  depth  and 
breadth  of  the  trough,  but  of  only  two  inches  in  width,  and  these  were  filled  with  the  water 
to  be  frozen. 

A  steam  engine  was  employed  to  pump  the  air  from  the  reservoir ;  this  being  done,  of 
course  the  ether  boiled,  and  the  vapor  of  the  ether  was  removed  by  the  engine  as  fa.st  as  it 
was  formed.  The  heat  required  to  vaporize  the  ether  was  derived  from  the  saline  water  in 
the  trough,  and  this  again  took  the  heat  from  the  water  in  the  cells ;  thus  eventually  every 
cell  of  water  was  converted  into  ice.  The  ether  was,  after  it  had  passed  through  the 
engine,  condensed  by  a  refrigeratory  of  the  ordinary  kind.  The  statement  made  by  the 
patentee  was  very  satisfactory,  as  it  regarded  the  cost  of  production.  An  apparatus  of  this 
kind  is  of  course  intended  for  hot  countries  only,  where  ice  becomes  actually  one  of  the 
necessaries  of  life. 

A  peculiar  physical  fact  connected  with  the  freezing  of  water  has  been  made  available 
to  some  important  uses.  Water  in  freezing  really  rejects  every  thing  it  may  contain — even 
air,  and  hence  solid  ice  is  actually  pwe  water.  This  may  be  easily  proved.  Make  a  good 
freezing  mixture,  and  place  some  water  in  a  flask,  and  while  it  is  undergoing  consolidation 
by  being  placed  in  the  frigorific  compound,  gently  agitate  it  with  a  feather.  Now,  if  the 
water  contains  spirit,  acid,  salt,  or  coloring  matter,  cither  of  them  are  alike  rejected,  and 
the  solid  obtained,  when  washed  from  the  matter  adhering  to  its  surface,  is  absolutely  pure 
solid  water. 

Tills  philosophic  fact,  although  it  has  only  been  subjected  to  examination  within  the 
last  few  years,  has  been  long  known. 


FULMINATING  SILVER.  557 

The  old  nobles  of  Russia,  when  they  desired  a  more  intoxicating  drink  than  usual, 
placed  their  wines  or  spirit  in  the  ice  of  their  frozen  rivers,  until  all  the  aqueous  portion 
was  frozen  ;  when  they  drank  the  ardent  fluid  accumulated  in  the  centre.  This  plan  has 
been  employed  also  for  concentrating  lemon  juice  and  the  like. 

FULMINATING  MERCURY,  C'N'Hg'O'  +  Ag.,  (dried  at  212\)  The  well-known  com- 
pound used  for  priming  percussion  caps.  It  was  analyzed  many  years  ago  by  Liebig,  and 
subsequently  by  Gay-Lussac.  Although  chemists  have  long  been  acquainted  with  the  true 
composition  of  fulminic  acid,  and  the  formula  of  fulminating  mercury  has  also  been  rendered 
almost  certain,  no  accurate  analysis  of  the  latter  compound  was  made  public  until  1855, 
when  M.  SchiselikofT  published  his  celebrated  paper  on  the  fulminates.  It  is  singular  that 
Liebig  and  Schischkoff  were  independently  engaged  at  the  same  time  in  investigating  the 
products  of  decomposition  of  the  fulminates.  The  formula  of  fulminic  acid,  and  also  that 
of  fulminating  mercury,  had  been  deduced  from  the  very  accurate  analysis  of  fulminating 
silver  made  by  Gay-Lussac  and  Liebig.  A  great  number  of  processes  for  the  preparation 
of  fulminating  mercury  have  been  published.  The  following  are  the  best  as  regards  econ- 
omy and  certainty : 

1.  One  part  of  mercury  is  to  be  dissolved  in  12  parts  of  nitric  acid,  of  sp.  gr.  1-3.  To 
the  solution  (as  soon  as  it  has  cooled  to  55^  F.)  8  parts  of  alcohol,  sp.  gr.  0"837,  are  to  be 
added ;  the  vessel  containing  the  mixture  is  to  be  heated  in  boiling  water  until  thick  white 
fumes  begin  to  form.  The  whole  is  then  set  in  a  cool  place  to  deposit  the  crystals  of 
fulminate. — Cremascoli. 

2.  One  part  of  mercury  is  to  be  dissolved  in  12  parts  of  nitric  acid,  sp.  gr.  1-340  to 
1'345,  in  a  flask  capable  of  holding  18  times  the  quantity  of  fluid  used.  When  the  metal 
is  dissolved,  the  solution  is  decanted  into  a  second  vessel  containing  S'V  parts  of  alcohol,  of 
90'  to  92°,  (Tralles,)  then  immediately  poured  back  into  the  first  vessel,  and  agitated  to 
promote  absorption  of  the  nitrous  acid.  In  five  to  ten  minutes  gas  bubbles  begin  to  rise, 
and  there  is  formed  at  the  bottom  of  the  vessel  a  strongly  refracting,  specifically  heavier 
liquid,  which  must  be  mixed  with  the  rest  by  gentle  agitation.  A  moment  then  arrives 
when  the  liquid  becomes  black  from  separation  of  metallic  mercury,  and  an  extremely 
violent  action  is  set  up,  with  evolution  of  a  thick  white  vapor,  and  traces  of  nitrous  acid ; 
this  action  must  be  moderated  by  gradually  pouring  in  5-7  parts  more  of  the  same  alcohol. 
The  blackening  then  immediately  disappears,  and  crystals  of  fulminating  mercury  begin  to 
separate.  When  the  fluid  has  become  cold,  all  the  fulminating  mercury  is  found  at  the 
bottom.     By  this  method  not  a  trace  of  mercury  remains  in  solution. — Liebig. 

The  fulminate  in  all  these  processes  is  to  be  collected  on  filters,  washed  with  distilled 
water,  and  dried.  The  violent  reaction  which  takes  place  when  the  solution  of  mercury 
reacts  on  the  alcohol,  is  essential  to  the  success  of  the  operation. 

With  regard  to  the  economy  of  the  above  methods,  it  has  been  found  that  1  part  of 
mercury  yields  the  following  proportions  of  fulminate : 

1st  process, 1-25 

2d       "  1-53 

C.  G.  W. 

FULMINATING  SILVER,  CUg-'N^O^  This  salt  corresponds  in  constitution  to  the 
fulminate  of  mercury ;  it  may  also  be  prepared  by  analogous  processes,  merely  substituting 
silver  for  mercury.  Preparation. — 1.  1  part  of  silver  is  to  be  dissolved  in  24  parts  of  nitric 
acid,  sp.  gr.  1-5,  previously  mixed  with  an  equal  weight  of  water.  To  the  solution  is  to  be 
added  alcohol  equal  in  weight  to  nitric  acid.  Produce,  1  -5  parts  of  fulminating  silver.  2. 
1  part  of  silver  is  to  be  dissolved  in  20  parts  of  nitric  acid,  sp.  gr.  1  "38.  To  the  solution  is 
to  be  added  27  parts  of  alcohol,  sp.  gr.  0-832.  The  mixture  is  to  be  heated  to  boiling,  and 
as  soon  as  it  shows  signs  of  becoming  turbid,  it  is  to  be  removed  from  the  fire,  and  a  quan- 
tity of  alcohol,  equal  in  weight  to  the  first,  is  to  be  poured  in.  The  liquid  is  now  to  be  al- 
lowed to  become  perfectly  cold,  when  the  fulminate  will  be  found  at  the  bottom  of  the 
vessel.  Produce,  equal  to  the  silver  employed.  3.  1  part  of  silver  is  to  be  dissolved  in 
ten  times  its  weight  of  nitric  acid,  sp.  gr.  1-36.  To  the  solution  is  to  be  added  20  parts  of 
alcohol,  sp.  gr.  0-83.  The  mixture  is  to  be  treated  as  in  the  second  mode  of  preparation, 
except  that  no  more  alcohol  is  to  be  added.  The  produce  should  be  in  fine  crystals. 
Whichever  mode  of  preparation  1)0  selected,  it  is  absolutely  necessary,  in  order  to  avoid 
fearful  accidents,  that  the  following  precautions  be  attended  to:  The  beakers  or  flasks  em- 
ployed must  be  two  or  three  times  larger  than  is  required  to  hold  the  ingredients,  for  if, 
owing  to  frothing  or  Ijoiling  over,  any  of  the  fluid  hapiiened  to  find  its  way  to  the  outside, 
and  dry  there,  an  explosion  might  ensue.  Care  must  also  be  taken  that  the  highly  inflam- 
mable vapors  given  off  during  the  preparation  do  not  come  near  any  flame.  The  salt,  when 
formed,  must  be  received  on  a  filter,  and  well  washed  with  cold  water.  It  is  safer  to  dry  it 
spontaneously,  or  over  oil  of  vitriol,  for  although  it  will  endure  a  heat  above  that  of  boiling 
water  before  exploding,  yet  when  warm,  the  slightest  touch  with  a  hard  substanc>e  is  often 
sufficient  to  cause  a  terrible  detonation.  A  spatula  of  pa.steboard  or  very  thin  wood  should 
be  employed  to  transfer  it  into  its  receptacle.     Fulminating  silver  should  not  be  kept  in 


558  FUR. 

glass  vessels,  for  fear  of  the  salt  finding  its  way  between  the  cork  or  stopper,  the  slightest 
movement  with  a  view  of  opening  the  vessel,  being  then  sufficient  to  cause  an  accident. 
Small  paper  boxes  are  the  safest  to  keep  it  in. 

Fulminating  silver  gives  a  more  violent  detonation  than  the  corresponding  mercurial 
compound.  The  presence  of  roughness  or  granular  particles  on  the  substances  with  which 
it  may  be  in  contact,  assists  greatly  in  causing  it  to  explode. 

Although  giving  so  violent  an  explosion  when  alone,  it  may  be  burnt  without  danger 
when  mixed  with  a  large  excess  of  oxide  of  copper,  as  in  the  ordinary  process  of  organic 
analysis.  It  then  gives  off  a  mixture  of  two  volumes  of  carbonic  acid,  and  one  volume  of 
nitrogen.  Gay-Lussac  and  Liebig  made  an  analysis  of  the  salt  in  this  manner,  with  the 
annexed  results : 


E.xperimont. 

Calculation. 

Carbon 

. 

-       1-9 

C* 

-       24 

-       8-0 

Nitrogen 

. 

-       9-2 

N^ 

-       28 

-       9-3 

Silver 

- 

-     V2-2 

Ag» 

-     216         - 

-     72-0 

Oxj-gen 

- 

-     10-7 

0* 

-       32 

-     10-7 

100-0  300  100-0 

For  further  remarks  on  the  fulminates,  see  Fulmixatixg  Mercury. — C.  G.  W. 

FUR.  Furs  arc  subject  to  injury  by  several  species  of  moths,  whose  instinct  leads  them 
to  deposit  their  eggs  at  the  roots  of  the  fine  hair  of  animals. 

Linna?us  mentions  five  species  that  prey  upon  cloth  and  furs,  of  which  Tinea  pellionclla, 
T.  I'Cfitionella  and  T.  tapclzella  are  the  most  destructive.  No  sooner  is  the  worm  hatched 
than  it  cats  its  path  through  the  fur,  and  continues  increasingly  destructive  until  it  arrives 
at  its  full  growth,  and  forms  itself  a  silken  covering,  fiom  which,  in  a  .short  time,  it  again 
emerges  a  perfect  moth. 

Another  cause  of  the  decay  of  fur  is  the  moisture  to  which  thfey  are  frequently  exposed ; 
the  delicate  structure  of  the  fine  under  fur  cannot  be  preserved  when  any  dampness  is  al- 
lowed to  remain  in  the  skin.  This  fact  is  well  known  to  the  leather  manufacturer,  who, 
having  wetted  his  skins,  allows  them  to  remain  in  a  damp  cellar  for  a  few  days,  for  the  pur- 
pose of  removing  the  hair,  which  is  pulled  out  with  the  greatest  facility,  after  remaining  only 
one  week  in  a  moist  condition.  It  follows  from  these  observations,  that  to  preserve  the  fur 
it  is  necessary  to  keep  them  dry,  and  to  protect  them  from  moths;  if  exposed  to  rain  or, 
damp,  they  must  be  dried  at  a  moderate  distance  from  the  fire ;  and  when  put  by  for  the 
summer  should  be  combed  and  beaten  with  a  small  cane,  and  very  carefully  secured  in  a 
dry  brown  paper  or  box,  into  which  moths  cannot  enter.  During  the  summer  they  should 
be  examined  once  a  month  to  be  again  beaten  and  aired,  if  the  situation  in  which  they  have 
been  placed  be  at  all  damp.  With  these  precautions,  the  most  valuable  furs  may  be  pre- 
served uninjured  for  many  years. 

FUSEL  OIL.  During  the  rectification  of  corn  or  grape  spirits  there  is  always  separated 
a  fiery  fo-tid  oil  of  nauseous  odor  and  taste.  It  is  this  substance  which  is  the  cause  of  the 
unpleasant  effects  which  are  produced  upon  most  persons  by  even  a  small  quantity  of  in- 
sufficiently rectified  whiskey  or  brandy.  Any  spirit  which  produces  milkincss  on  the  addi- 
tion of  four  or  five  times  its  volume  of  water,  may  be  suspected  to  contain  it.  By  repeated 
rectification  every  trace  may  be  removed. 

Fusel  oil  invariably  consists  of  one  or  more  homologues  of  the  vinic  alcohol,  (CH^O",) 
mixed  with  variable  quantities  of  the  latter  substance  and  water.  The  nature  of  fusel  oil 
varies  much  with  the  source  from  whence  it  is  obtained.  That  which  is  ordinarily  sold  in 
this  country  for  the  purpose  of  yielding  pear  essence  consists  mainly  of  the  amylic  alcohol, 
(C^"II"0'^,)  mixed  with  from  one-fourth  to  one-fifth  of  spirit  of  wine. 

Tlie  progress  of  organic  chemistry  has  been  greatly  assisted  by  the  researches  which 
have  been  made  upon  fusel  oil,  almost  all  the  amylic  compounds  hitherto  obtained  having 
been  directly  or  indirectly  obtained  from  it. 

To  obtain  fusel  oil  in  a  state  of  purity  it  is  necessary,  in  the  first  place,  to  rectify  it  frac- 
tionally. By  this  means  it  will  be  found  that  much  alcohol  can  be  removed  at  once.  If  a 
great  quantity  of  water  and  very  little  vinic  alcohol  be  present,  the  simplest  mode  of  puri- 
fication is  to  shake  it  with  water,  by  which  means  common  alcohol  is  removed  in  solution, 
while  the  amylic  alcohol,  owing  to  its  comparative  insolubility,  may  be  easily  separated  by 
the  tap-funnel.  After  drying  over  chloride  of  calcium,  it  is  to  be  again  rectified  once  or 
twice,  only  that  portion  distilling  at  about  269'6°  Fahr.  (132°  Cent.)  being  received.  The 
product  of  this  operation  is  pure  amylic  alcohol,  from  which  an  immense  number  of  deri- 
vations of  the  amylic  series  can  be  obtained.  By  treatment  with  sulphuric  acid  and  bi- 
chromate of  potash  it  is  converted  into  valerianic  acid.  In  this  manner  all  the  valerianic  acid 
now  so  nnich  emploj-ed  in  medicine  is  prepared.  By  distilling  amylic  alcohol  with  sul- 
phuric acid  and  acetate  of  potash,  we  obtain  the  acetate  of  amyle,  commercially  known  as 
jargonelle  pear  essence. 

The  foreign  fusel  oils  obtained  from  the  grape  marc  contain  several  homologues  higher 


GALVANIZED  IRON". 


559 


and  lower  ia  the  series  than  the  amylic  alcohol.     In  fact,  it  would  appear  that  during  the 
fermentation  of  grapes  there  are  formed,  not  only  alcohols,  but  ethers  and  acids. 

M.  Chancel,  by  repeatedly  rectifying  the  dehydrated  and  more  volatile  portions  of  the 
residues  of  the  distillation  of  grape  marc  alcohol,  succeeded  in  isolating  a  fluid  boiling  at 
205"  Fahr.  This  proved  to  be  pure  propionic  alcohol.  M.  Wurtz  has  also  been  able  to 
obtain  the  butylic  alcohol  by  rectifying  certain  specimens  of  potato  oil. 

All  fusel  oils  are  not  so  complex.  The  author  of  this  article  has  repeatedly  examined 
specimens  of  English  and  Scotch  fusel  oil,  which  did  not  contain  any  thing  save  the  ethylic 
and  amylic  alcohols,  accompanied  by  small  portions  of  the  acids,  which  are  procured  by 
their  oxidation.  M.  Chancel  has  given  the  following  equations,  which  explain  the  manner 
in  which  saccharine  matters  break  up  into  homologous  alcohols  under  the  influence  of  fer- 
ments. I  have  reduced  the  unitary  notation  employed  by  him  into  the  ordinary  formulae 
used  iu  this  country,  in  order  to  render  the  relations  as  clear  as  possible  to  the  reader. 
2C'-H'^0"  =  8C0=  +  4C^II°0^ 

Glucose  Alcohol.  . 

2C''H''0''  _  SCO-  +  C^IFO-  +  2C''irO'  +  2no. 

Propionic  alcohol. 
2C"H'=0'^  _  gQQ".  ^  2C^IP°0^  +  4nO. 


2Ql".^l".Qli 


Butylic  alcohol. 
8C0^  +  C^H'-O^  +  C'H'W  +  4H0. 


Amylic  alcohol. 

M.  Chancel  appears  to  consider  the  last  equation  as  indicating  the  necessity  of  propionic 
alcohol  being  always  formed  wherever  amylic  alcohol  is  generated ;  but  this  is  not  in  ac- 
cordance with  the  results  of  those  chemists  who  have  examined  crude  amylic  alcohol  re- 
peatedly for  propionic  alcohol,  but  without  finding  any.  The  formation  of  these  ijitcrest- 
ing  homologues  appears  therefore  to  depend  upon  special  circumstances  connected  with  the 
fermentation. 

The  caproic  alcohol  is  also  contained  in  certain  varieties  of  fusel  oil. 

Fusel  oil  has  been  patented  as  a  solvent  for  quinine,  but  its  odor,  and  more  especially 
that  produced  by  its  oxidation,  so  persistently  adheres  to  any  thing  with  which  it  has  been 
in  contact,  that  great  care  is  requisite  in  the  purification.  It  is  remarkable  that  at  the  first 
instant  of  smelling  most  specimens  of  fusel  oil,  the  odor  is  not  unpleasant,  but  in  a  very 
few  seconds  it  becomes  exceedingly  repulsive,  and  provokes  coughing. — C.  G.  W. 


G 


GALVANIZED  IROX.  This  is  the  name,  improperly  given,  first  in  France,  and  sub- 
sequently adopted  in  this  country,  to  iron  coated  with  zinc  by  a  peculiar  patent  process. 

In  1837,  Mr.  II.  W.  Crawfurd  patented  a  process  for  zincing  iron.  In  the  '■'■  Repcrtorn 
of  Patent  Inventions''''  his  process  is  thus  described:  Sheet  iron,  iron  castings,  and  various 
other  objects  in  iron,  are  cleaned  and  scoured  by  immersion  in  a  bath  of  water,  acidulated 
with  sulphuric  acid,  heated  in  a  leaden  vessel,  or  used  cold  in  one  of  wood,  just  to  remove 
the  oxide.  They  are  then  thrown  into  cold  water,  and  taken  out  one  at  a  time  to  be 
scoured  with  sand  and  water  with  a  piece  of  cork,  or  more  usually  with  a  piece  of  the  husk 
of  the  cocoa  nut,  the  ends  of  the  fibres  of  which  serve  as  a  brush,  and  the  plates  are  after- 
wards thrown  into  cold  water. 

Pure  zinc  covered  with  a  thick  layer  of  sal  ammoniac  is  then  melted  in  a  hath,  and  the 
iron,  if  in  sheets,  is  dipped  several  sheets  at  a  time  in  a  cradle  or  grating.  The  sheets  are 
slowly  raised  to  allow  the  superfluous  zinc  to  drain  off,  and  are  thrown  whilst  hot  into  cold 
water,  on  removal  from  which  they  only  require  to  be  wiped  dry. 

Thick  pieces  are  heated,  before  immersion,  in  a  reverbeiatory  furnace,  to  avoid  cooling 
the  zinc.  Chains  are  similarly  treated,  and  on  removal  from  the  zinc  recjuire  to  l)e  shaken 
until  cold,  to  avoid  the  links  lieing  soldered  together.  Nails  and  small  articles  are  dipped 
in  muriatic  acid,  and  dried  in  a  reverberatory  furnace,  and  then  thrown  all  together  in  the 
zinc,  covered  with  the  sal  ammoniac,  left  for  one  minute,  and  taken  out  slowly  with  an  iron 
.skimmer.  They  come  out  in  a  mass,  .soldered  together,  and  for  their  separation  arc  after- 
wards placed  in  a  crucible  and  surrounded  with  charcoal  powder,  then  heated  to  redness  and 
shaken  about  until  cold,  for  their  separation.  Wire  is  reeled  through  the  zinc,  into  which 
it  is  compelled  to  dip  l)y  a  fork  or  other  contrivance.  It  will  be  understood  that  the  zinc 
is  melted  with  a  thick  coat  of  sal  ammoniac  to  prevent  the  loss  of  zinc  by  oxidation. 


560  GAKNET. 

Mr.  Mallett  coated  iron  with  zinc  by  the  following  process : 

The  plates  are  immersed  in  a  cleansing  bath  of  equal  parts  of  sulphuric  or  muriatic 
acid  and  water,  used  warm ;  the  works  are  then  hammered  and  scrubbed  with  emery  and 
sand  to  detach  the  scales,  and  to  thoroughly  clean  them ;  they  are  then  immersed  in  a 
"  preparing  bath  "  of  equal  parts  of  saturated  solutions  of  muriate  of  zinc  and  sal  ammoniac, 
from  which  the  works  are  transferred  to  a  fluid  metallic  bath,  consisting  of  202  parts  of 
mercury  and  1,292  parts  of  zinc,  both  by  weight,  to  every  ton  weight  of  which  alloy  is  added 
above  one  pound  of  either  potassium  or  sodium,  the  latter  being  preferred.  As  soon  as  the 
cleaned  iron  works  have  attained  the  melting  heat  of  the  triple  alloy,  they  are  removed, 
having  become  thoroughly  coated  with  zinc.  At  the  proper  fusing  temperature  of  this 
alloy,  which  is  about  680^  Fahr.,  it  will  dissolve  a  plate  of  wrought  iron  of  an  eighth  of  an 
inch  thick  in  a  few  seconds. 

Morewood  and  Rogers'  galvanized  tinned  iron  is  prepared  under  several  patents.  Their 
process  is  as  follows : 

The  sheets  are  pickled,  scoured,  and  cleaned,  just  the  same  as  for  ordinary  tinning.  A 
large  wooden  l)ath  is  then  half  filled  with  a  dilute  solution  of  muriate  of  tin,  prepared  by 
dissolving  metallic  tin  in  concentrated  muriatic  acid,  which  requires  a  period  of  two  or 
three  days.  Two  quarts  of  the  saturated  solution  are  added  to  300  or  400  gallons  of 
the  water  contained  in  the  bath.  Over  the  bottom  of  the  bath  is  first  spread  a  thin  layer 
of  finely-granulated  zinc,  then  a  cleaned  iron  plate,  and  so  on,  a  layer  of  granulated  zinc 
and  a  cleaned  iron  plate  alternately,  until  the  bath  is  full.  The  zinc  and  iron,  together 
with  the  fluid,  constitute  a  weak  galvanic  battery,  and  the  tin  is  deposited  from  the  solution 
so  as  to  coat  the  iron  with  a  dull  uniform  layer  of  metallic  tin  in  about  two  hours. 

The  tinned  iron  is  then  passed  through  a  bath  containing  fluid  zinc,  covered  with  sal 
ammoniac  mixed  with  earthy  matter,  to  lessen  the  volatilization  of  the  sal  ammoniac,  which 
becomes  as  fluid  as  treacle.  Two  iron  rollers  immersed  below  the  surface  of  the  zinc,  are 
fixed  to  the  bath  and  are  driven  by  machinery  to  carry  the  plates  through  the  fluid  metal 
at  any  velocity  previously  determined.  The  plates  are  received  one  by  one  from  the  tin- 
ning bath,  drained  for  a  short  time,  and  passed  at  once,  whilst  still  wet,  by  means  of  the 
rollers,  through  the  bath  as  described.  The  plates  take  up  a  very  regular  and  smooth  layer 
of  zinc,  which,  owing  to  the  presence  of  the  tin  beneath,  assumes  its  natural  crystalline 
character,  giving  the  plates  an  appearance  resembling  that  known  as  the  nioiree  metallique. 
— See  HunVs  Handbook  to  the  Great  Exhihiiion. 

It  is  stated  that  galvanized  iron  plates,  cut  with  shears  so  as  to  expose  the  central  iron, 
become  zinced  round  the  edges,  and  at  the  holes  where  the  nails  were  driven.  We  are 
also  informed  that  nngalvanizcd  iron  will,  if  moist  when  near  galvanized  plate,  become 
zinced,  and  that  telegraph  wires,  where  cut  through,  become  coated  by  the  action  of  the 
rain  water  on  the  galvanized  portion  of  the  surfaces. 

It  has  been  stated  that  the  galvanized  iron  is  not  more  durable  than  unprotected  iron ; 
that,  indeed,  where  the  zinc  is  by  any  accident  removed,  the  destruction  is  more  rapid  than 
ordinary.  We  have  made  especial  inquiries,  and  find  that  in  forges  where  there  is  any 
escape  of  sulphur  vapor  the  galvanized  iron  does  not  stand  well,  but  that  under  all  ordi- 
nary circumstances  it  has  the  merit  of  great  durability  in  addition  to  its  other  good  qualities. 

GARXET.  (Grcnat,  Fr.)  Garnet  is  a  silicate  of  some  base,  which  may  be  lime,  mag- 
nesia, oxide  of  iron,  &c. 

There  are  six  sub-species  of  garnet,  viz. : 

I.  Alumina-lime  garnet,  consisting  of  the  silicates  of  alumina  and  lime. 

II.  Ahniiina-magnesia  garnet,  consisting  of  the  silicates  of  alumina  and  magnesia. 

III.  Alumina-iron  garnet,  consisting  of  the  silicates  of  alumina  and  iron. 

IV.  Alnmina-manganesc  garnet,  consisting  of  the  silicates  of  alumina  and  manganese. 

V.  Iron-lime  garnet,  consisting  of  the  silicates  of  iron  and  lime.  ' 

YI.  Lime-ehrome  garnet,  consisting  of  the  silicates  of  lime  and  oxide  of  chromium. 

I.  Lime-garnet,  or  grossular,  is  composed  of  silica,  40-1 ;  alumina,  22'7 ;  lime,  37"2  =r 
100-0.  Color,  pale  greenish,  clear  red,  and  reddish  orange,  cinnamon  color.  Before  the 
blowpipe,  fuses  to  a  slightly  greenish  glass  or  enamel ;  soluble,  when  powdered,  in  concen- 
trated muriatic  acid. 

This  section  comprises  cinnamon-stone  or  Essonite,  grossular  or  Wiluite,  Romanzovite, 
topazoUte,  and  succinite. 

II.  Magnesia-garnet  is  of  a  deep  coal-black  color,  with  a  resinous  lustre.  The  variety 
from  Arendal  is  composed  of  silica,  42-45 ;  alumina,  22-47 ;  protoxide  of  iron,  9-29 ;  pro- 
toxide of  manganese,  6-27;  magnesia,  13-43;  lime,  6-53  =  10044. — (Wdchfmeister.)  Be- 
fore the  blowpipe,  easily  fusible,  formmg  with  intumescence  a  dark  grayi.sh-green  globule, 
which  is  non-magnetic. 

III.  Iron-garnet  comprises  the  almandine  or  precious  garnet,  allochroite,  and  common 
garnet.  It  is  composed  of  silica,  36-3;  alumina,  20-5;  protoxide  of  iron,  43"2  =  100-0. 
Before  the  blowpipe,  fuses  rather  easily,  with  an  iron  reaction. 

IV.  Manganese-garnet,  or  spessartine,  is  of  a  brownish-red  color,  and  is  composed  of 


GEMS,  ARTIFICIAL.  561 

silica,  35'83  ;  alumina,  18 '06  ;  protoxide  of  iron,  14-93;  protoxide  of  manganese,  30'96  = 
99 '78.  (Analysis  of  M.  garnet  from  Haddam,  U.  S.,  by  Seyhert.)  Before  the  blowpipe, 
gives  a  manganese  reaction. 

V.  Iron-lime  garnet  includes  aplome,  colophonite,  melauite,  and  pyreneite.  These  vary 
in  color  from  dark  red,  brownish  black,  to  black,  and  possess  a  shining  lustre,  which  is 
sometimes  resinous,  as  in  colophonite. 

Analysis  of  the  aplome  of  Alteuau: — Silica,  35-64;  lime,  29-22;  protoxide  of  iron, 
30-<iO;  protoxide  of  manganese,  3-01  ;  potash,  2-35  =  100-22. —  Wdchtmeister. 

VI.  Lime-chrome  garnet,  or  ouvarovite,  is  of  an  emerald-green  color.  Sp.  gr.,  3-418. 
Before  the  blowpipe  it  is  infusible  alone,  but  with  borax  affords  a  chrome-green  glass.  It 
occurs  at  Bissersk,  in  Russia. 

Analysis  by  Erdmann: — Silica,  36-93;  alumina,  5-68;  peroxide  of  iron,  1-96;  oxide 
of  chrome,  21-84;  magnesia,  1-54;  carbonate  of  lime,  31-66;  oxide  of  copper,  a  trace 
=  99-58.  ■ 

The  garnet  varies  greatly  in  transparency,  fracture,  and  color ;  but  when  the  colors  are 
rich,  and  the  stone  is  free  from  flaws,  it  constitutes  a  valuable  gem,  which  may  be  distin- 
guished by  the  following  properties : 

The  color  should  be  blood  or  cherry-red ;  on  the  one  hand  often  mixed  more  or  less 
with  blue,  so  as  to  present  various  shades  of  crimson,  purple,  and  reddish  violet,  and  on 
the  other  hand,  with  yellow,  so  as  to  form  orange  red  and  hyacinth  brown. 

The  stones  vary  in  size  from  the  smallest  pieces  that  can  be  worked  to  the  size  of  a  nut. 
When  above  that  size  they  are  scarcely  ever  free  from  flaws,  or  sufficiently  transparent  for 
the  purposes  of  the  jeweller. 

The  garnets  of  commerce  are  procured  from  Bohemia,  Ceylon,  Pegu,  aiid  the  Brazils. 
By  jewellers  they  are  classed  as  Syrian,  Bohemian,  or  Cingalese,  rather  from  their  relatiTe 
value  and  fineness,  than  with  any  reference  to  the  country  from  which  they  are  supposed  to 
have  been  brought. 

Those  most  esteemed  are  called  Syrian  garnets,  not  because  they  come  from  Syria,  but 
after  Syrian,  the  capital  of  Pegu,  which  city  was  formerly  the  chief  mart  for  the  finest  gar- 
nets. The  color  of  the  Syrian  garnet  is  violet-purple,  which,  in  some  rare  instances,  vies 
with  that  of  the  finest  oriental  amethyst ;  but  it  may  be  distinguished  from  the  latter  by 
acquiring  an  orange  tint  by  candle-light.  The  Syrian  garnet  may  be  also  distinguished  from 
all  the  other  varieties  of  garnet  in  preserving  its  color  (even  when  of  considerable  thickness 
and  unassisted  by  foil)  unmixed  with  the  black  tint  which  usually  obscures  this  gem.  The 
Bohemian  garnet  is  generally  of  a  dull  poppy-red  color,  with  a  very  perceptible  hyacinth- 
orange  tint  when  held  between  the  eye  and  the  light.  When  the  color  is  a  full  crimson  it 
is  called  pyrope,  or  fire-garnet — a  stone  of  considerable  value  when  perfect  and  of  large 
size. 

The  best  manner  of  cutting  the  pyrope  is  en  cahochon^  with  one  or  two  rows  of  small 
facets  round  the  girdle  of  the  stone.  The  color  appeal's  more  or  less  black  when  the  stone 
is  cut  in  steps,  but  when  cut  en  cabockon^  the  points  on  which  the  light  falls  display  a 
brilliant  fire-red. 

Garnet  is  easily  worked,  and  when  facet-cut  is  nearly  always  (on  account  of  the  depth  of 
its  color)  formed  into  thin  tables,  which  are  sometimes  concave  or  hollowed  out  on  the 
under  side.  Cut  stones  of  this  latter  description,  when  skilfully  set,  with  a  bright  silver 
foil,  have  often  been  sold  as  rubies. 

The  garnet  may  be  distinguished  from  corundum  or  spinel  by  its  duller  color.  Coarse 
garnets  reduced  to  a  fine  powder  are  sometimes  used  as  a  substitute  for  emery  in  polishing 
metals.— H.  W.  B. 

GAS  PIPES.  In  the  present  method  of  manufacturing  the  patent  welded  tube,  the  end 
of  the  skelp  is  bent  to  the  circular  form,  its  entire  length  is  raised  to  the  welSing  heat  in  an 
appropriate  furnace,  and  as  it  leaves  the  furnace  almost  at  the  point  of  fusion  it  is  dragged 
by  the  chain  of  a  draw-bench,  after  the  manner  of  wire,  through  a  pair  of  tongs  with  two 
bell-mouthed  jaws.  These  are  opened  at  the  moment  of  introducing  the  end  of  the  skelp, 
which  is  welded  without  the  agency  of  a  mandrel. 

By  this  ingenious  arrangement  wrought-iron  tubes  may  be  made  from  the  diameter  of 
six  inches  internally,  and  about  one-eighth  to  three-eighths  of  an  inch  thick,  to  as  small  as 
one-quarter  inch  diameter  and  one-tenth  bore ;  and  so  admirably  is  the  joining  effected  in 
those  of  the  best  description  that  they  will  withstand  the  greatest  pressures  of  gas,  steam, 
or  water  to  which  they  have  been  subjected,  and  they  admit  of  being  iK'ut,  both  in  the 
heated  and  cold  state,  almost  with  impunity.  Sometimes  the  tubes  are  made  one  u]wn  the 
other,  when  greater  thickness  is  required,  but  these  stout  pipes  and  those  larger  than  three 
inches  are  comparatively  but  little  used. — {lloltzapfcl.) 

GEMS,  ARTIFICIAL.  These  are  glasses,  the  material  of  which  they  are  composed 
being  called  Strass. 

Strass,  the  paste  or  glass  which  generally  forms  the  principal  ingredient  of  imitation 
gems,  is  called  after  the  name  of  a  German  jeweller,  by  whom  it  was  invented,  at  the  com- 
VoL.  III.— 36 


562 


GEMS,  ARTIFICIAL. 


niencement  of  the  last  century.  It  is  composed  of  silica,  potash,  borax,  the  various  oxides 
of  lead,  and  sometimes  of  arsenic ;  chemically  it  may  be  regarded  as  a  double  silicate  of 
potash  and  lead. 

The  silica  may  be  furnished  either  by  rock  crystal,  white  sand,  or  flint ;  but  of  these  the 
first  is  to  be  preferred,  one  of  the  principal  considerations  in  these  preparations  being  the 
extreme  purity  of  the  materials  or  ingredients  employed.  In  this  manufacture,  which  is  of 
more  importance  and  attended  with  greater  difficulty  than  most  persons  imagine,  perfect 
success  (independently  of  the  choice  of  materials)  depends  upon  the  care  taken,  and  the 
precautions  to  be  observed.  No  crucibles  should  be  used  but  those  which  have  been  proved, 
both  as  regards  their  composition,  their  power  of  withstanding  the  strongest  heat,  and  their 
impenetrability  to  the  action  of  metallic  oxides. 

All  the  substances  to  be  melted  should  be  first  pulverized,  and  even  ground  with  the 
greatest  care.  It  should  be  remembered  that  the  most  perfect  mixture  can  only  be  effected 
by  numerous  siftings,  and  that  a  separate  sieve  should  be  used  for  each  ingredient,  and 
never  be  made  to  serve  for  different  substances.  When  mixed,  the  materials  should  be 
melted  in  a  crucible  placed  in  the  middle  of  a  cylindrical  furnace  terminated  in  a  dome,  the 
height  of  which  should  be  7  feet  6  inches,  and  its  diameter  4  feet  3  inches.  The  fuel  should 
consist  as  much  as  possible  of  thoroughly  dry  wood,  chopped  very  small.  The  melting 
should  be  effected  by  means  of  a  heat  raised  by  degrees,  and  then  steadily  maintained,  espe- 
cially at  the  maximum  temperature ;  then,  when  once  the  melting  has  been  thoroughly 
accomplished,  which  cannot  be  in  less  than  from  twenty  to  thirty  hours,  the  crucible  must 
be  allowed  to  cool  very  slowly. 

The  art  of  imitating  precious  stones  in  paste  has  amazingly  improved  since  the  time  of 
Strass,  as  was  shown  by  the  results  of  the  great  Paris  exposition  of  1855.  The  imitations, 
especially  as  regards  certain  colors,  leave  little  to  be  desired ;  but  there  is  something  still 
in  that  respect  in  which  the  imitation  is  far  from  being  perfect. 

Now  that  it  is  proved  that  the  alkalies  and  vitrifiable  earths  are  oxides  of  the  metals,  all 
that  has  to  be  done  to  obtain  the  finest  effects,  is  to  combine  them  skilfully,  and  in  their 
present  forms,  with  other  artificially  prepared  metallic  oxides  which  have  undergone  the 
process  of  vitrification. 

Experiments  ought  to  be  made  with  all  oxidizable  and  vitrifiable  substances,  with  the 
different  salts,  fluates,  phosphates,  phosphoric  acid,  &c. 

The  following  are  some  of  the  mixtures  generally  known,  but  it  must  be  observed 
here  that  each  artist  has  his  own  processes,  ingredients,  and  proportions. 

Common  Strass. 

Litharge,  'ZV-IG;  white  sand,  57-73;  potash,  7'7l. 

Strass  of  Douhaut-  Wieland. 


Sifted  rock  crystal 
Boracic  acid 
Minium  (purest)  - 

Calcined  flints 
Pure  potash 


Deutoxide  of  arsenic 
Potash  (purest) 


2897-5 

181-18 
4451-37 

English  Strass. 
962  5       I     Calcined  borax 
481-25    I    Fine  white  lead 

Strass  Bastenaire. 


4-92 

1608-53 


361-9 
120-89 


1. 

2. 

3. 

4. 

5. 

' 

Grains. 

Grains. 

Grains. 

Grains. 

Grains. 

"White  sand  treated  with  hydrochlo- 

ric acid     .        .         -         -         - 

1543-23 

1543-23 

385-8 

3S5-8 

385-8 

Minium,  first  quality     - 

6-16 

2156- 

771-61 

925-8 

848-65 

White  potash,  well  calcined  - 

370-32 

493-76 

108-2 

61-72 

154-32 

Calcined  borax     .... 

308-04 

185-16 

. 

92-58 

123-45 

'    Crystallized  nitrate  of  potash  (nitre) 

185-16 

- 

123-44 

- 

77-16 

Peroxide  of  manganese 

Gl-72 

. 

- 

154-32 

- 

,   Deutoxide  of  arsenic    - 

1 

• 

9-26 

- 

23-15 

• 

Variouslt  Colored  Strass. 

Topaz:  No.  1. 

Whitest  strass,  842-079 ;  glass  of  antimony,  36*421 ;  purple  of  Cassius,  0-738. 

Another. 
White  lead  of  Clichy,  771*6;  flints  calcined  and  pulverized,  771*6. 


GEMS,  ARTIFICIAL. 


563 


•«■  A  nother. 

White  sand,  well  dressed      -      1543-23         Oxide  of  silver        -        -        -      77-16 
Borax,  calcined     -         -         -        138-88         Calcined  potash       -         -         -     493-76 
Minium         ....      2237-64 
Sapphire:  Whitest  strass,  3858-087  ;  pure  oxide  of  cobalt,  57-708. 
Ditto:  another.     Very  fine  strass,  481-25;  purest  oxide  of  cobalt,  1"697. 

Strass,  3858-087;  pure  green  oxide  of  copper,  35-643;  oxide  of 


Emerald,  No.  1. 
chrome,  1-697. 

Ditto :  ordinary. 

Ditto :  another, 
potash,  334-45, 


Strass,  7716-174;  acetate  of  copper,  61-11 ;  oxide  of  iron,  12*731. 
Strass,  481-25;  oxide  of  copper  precipitated  from  the  nitrate  by 

Emeralds  [Bastenaire.) 


1. 

2. 

Well  washed  sand      -        .        -        -        . 
Minium      -        -        -        -        -   .     - 
White  potash,  calcined       -        .        .        . 

Borax,  calcined 

Yellow  oxide  of  antimony           ... 
Pure  oxide  of  cobalt           .... 
Green  oxide  of  chrome      .... 

Grains. 

154-32 

231-48 

46-29 

30-86 

7-71 

1-54 

Grains. 

154-32 

231-48 

77-16 

30-86 

3-85 

Amethyst  (Bastenaire. 


Pale. 

Deep-colored. 

Strass         -        -        -        -     .    -        '        - 
Oxide  of  manganese  ..... 

Oxide  of  cobalt 

Purple  of  Cassius 

Grains. 
7716-17 
20-39 
0-848 

Grains. 

3858-08 

36-55 

20-39 

0-848 

Aquamarine. 

Strass,  2913-50;  glass  of  antimony,  20*370;  oxide  of  cobalt,  1-265. 

Syrian  Garnet. 


Strass 

Glass  of  antimony 
Purple  of  Cassius 
Oxide  of  manganese 


Grains. 

427*931 

215-815 

1-697 

1-697 


Grains. 
484-25 


2-150 


Observations. — For  topaz,  No.  1,  the  clearest  and  most  transparent  glass  of  antimony 
should  be  used.  Frequently  this  mixture  only  yields  an  opaque  mass,  translucent  on  the 
edges,  and  transmitting  in  thin  fragments  a  red  color  when  held  between  the  eye  and  the 
light ;  in  that  case -rubies  may  be  made  of  it. 

To  make  them,  a  portion  of  the  topaz  material  is  taken,  and  mixed  with  eight  parts  of 
fine  strass ;  these  are  melted  in  a  Hessian  crucible  for  thirty  hours  in  a  potter's  furnace, 
and  the  result  is  a  beautiful  yellow  glass-like  strass,  which,  when  cut,  produces  an  imitation 
of  the  finest  oriental  rubies. 

These  may  be  made  of  another  tint  by  using  the  following  propoi-tions : 

Strass,  2411*25;  oxide  of  manganese,  61-310. 

In  the  emerald,  No.  1,  by  increasing  the  proportion  of  chrome  or  oxide  of  copper,  and 
mixing  with  it  oxide  of  iron,  the  green  shade  may  be  varied,  and  the  peridot  or  deep-tinted 
emerald  may  be  imitated. 

The  manufacture  of  artificial  gems  has  acquired  an  extreme  development;  immense 
factories  are  established  at  Septmoncal  in  the  Jura,  furnishing  employment  to  more  than 
100  work-people,  who  produce  fabulous  quantities. 

Many  ingenious  persons  in  Paris  vie  with  one  another  in  bringing  to  perfection  the  most 
perfect  processes,  and  produce  truly  surprising  results.     M.  Savary  especially,  in  his  mag- 


564:  GERMAN  SILVER. 

nificent  collections,  and  his  per.cct  imitation  of  celebrated  diamonds,  has  arrived  at  a  degree 
of  excellence  which,  apparently,  can  scarcely  be  surpassed. 

We  have  alluded  only  to  those  imitations  of  gems  in  glass  of  which  a  large  portion  oi 
the  cheap  jewellery  is  formed.  Some  very  successful  attempts  have  been  made  to  manu- 
facture true  gems  by  an  artificial  process.  M.  Ebelmen  has  done  much  in  this  direction, 
and  M.  Henri  Sainte-Claire  Deville  and  M.  Henri  Caron  communicated  to  the  Academy  of 
Sciences  of  Paris,  in  April,  1858,  a  process  which  they  had  discovered  for  the  production  of 
a  number  of  the  gems  which  belong  to  the  corundum  class,  as  the  ruby,  sapphire,  &c. 
Essentially,  the  process  consisted  in  exposing  the  fluoride  of  aluminium,  mixed  with  a  little 
charcoal  and  boracic  acid,  in  a  black  lead  crucible,  protected  from  the  action  of  the  air,  to 
a  white  heat  for  about  an  hour.  For  details  of  the  process  see  Comptes  RenduSy  Annales 
de  Chimie. 

GERMAN  SILVER.  See  Allot  and  Copper.  M.  Gersdorf,  of  Vienna,  states  that  the 
proportion  of  the  metals  in  this  alloy  should  vary  according  to  the  uses  for  which  it  is  des- 
tined. When  intended  as  a  substitute  for  silver,  it  should  be  composed  of  25  parts  of 
niclcel  25  of  zinc,  and  50  of  copper.  An  alloy  better  adapted  for  rolling  consists  of  25  of 
nickel^  20  of  zinc,  and  60  of  copper.  Castings,  such  as  candlesticks,  bells,  &c.,,  may  be 
made  of  an  alloy  consisting  of  20  of  nickel,  20  of  zinc,  and  60  of  copper,  to  which  3  of  lead 
are  added.  The  addition  of  2'  or  2^  of  iron  (in  the  shape  of  tin  plate  ?)  renders  the  alloys 
much  whiter,  but  at  the  same  time  harder  and  more  brittle. 

Keferstein  has  given  the  following  analysis  of  the  genuine  German  silver,  as  made  from 
the  original  ore  found  in  Hildburghausen,  near  Suhl,  in  Henneberg : 

Copper 40-4 

Nickel 31-6 

Zine  ------ 25-4 

*"        Iron  -         -         -         - 2-6 

100-0 

Chinese  pakfong,  a  white  alloy,  according  to  the  same  authority,  consists  of  5  parts  of 
copper  alloyed  with  7  parts  of  nickel  and  T  parts  of  zinc. 

The  best  alloy  for  making  bc<iring&,  bushes,  and  steps  for  the  steel  or  iron  gudgeons 
and  pivots  of  machinery  to  run  in,  is  said  to  consist  of  90  parts  of  copper,  5  of  zinc,  and  5 
of  antimony. 

GLASS.  Bohemian  glass. — M.  Peligot  states  that  the  hard  glass  of  Bohemia  is  com- 
posed of  100  parts  of  silica,  12  parts  of  quickhme,  and  only  28  parts  of  carbonate  of  pot- 
ash. These  proportions  give  a  glass  quite  unmanageable  in  ordinary  furnaces ;  but  the  ad- 
dition of  a  comparatively  small  quantity  of  boracic  acid  is  capable  of  determining  fusion, 
and  the  result  is  a  glass  having  all  the  requisite  limpidity  at  a  high  temperature,  and  pos- 
sessing at  the  same  time  a  great  brilliancy  and  hardness. 

The  Bohemian  glass  is,  within  certain  limits,  perfectly  elastic,  and  very  sonorous ;  when 
well  made,  it  is  sutficiently  hard  to  strike  fire  with  steel,  and  is  scratched  with  difficulty. 
The  lead  glasses,  on  the  other  hand,  have  but  little  hardness,  and  less  ii^  proportion  as  they 
contain  more  oxide  of  lead ;  besides  which,  they  rapidly  lose  their  brilliancy  by  use.^ 

The  silica  which  is  employed  in  Bohemia  in  the  manufocturc  of  glass,  is  obtained  by 
calcining  crystalline  quarts,  and.  afterwards  pounding  it  while  dry.  When  Che  quartz  has 
been  heated  to  a  cherry  red,  it  is  withdrawn  from  the  fire,  and  thrown  immediately  into 
cold  water. 

Almost  all  the  Bohemian  glass  is  a  potash  glass,  because  soda  and  its  salts  give  to  glass 
a  sensible  yellowish  tint.  The  limestone  which  is  used  is  as  white  as  CaiTara  marble.  The 
clay  employed  for  the  crucibles  is  very  white,  and  consists  of  silica,  45-8;  alumina,  40-4; 
and  water,  13'8. 

The  manufacture  of  glass  in  Bohemia  is  of  very  high  antiquity,  and  the  same  peculiari- 
ties have  always  belonged  to  the  true  Bohemian  manufacture. 

In  our  modern  times  the  Bohemian  glass  has  been  more  especially  celebrated  for  the 
beautiful  varieties  of  colors  which  are  produced.     See  Glass,  colored. 

Venetian  glass. — From  an  early  date  the  cfty  of  Venice  has  been  celebrated  for  its 
glass ;  the  reticulated  glass,  the  crackle  glass,,  and  the  glass  paper-weights,  or  millefiore,  are 
all  due  to  the  Venetians. 

The  manufacture  of  glass  beads  at  Murano,  near  Venice,  has  been  carried  on  for  an 
indefinite  period,  and  Africa  and  Asia  have  been  supplied  from  their  glass-houses.  The 
process  is  most  ingeniously  simple.  Tubes  of  glass,  of  every  color,  are  drawn  out  to  great 
lengths  in  a  gallery  adjoining  the  glass-house  pots,  in  the  same  way  as  the  more  moderate 
lengths  of  thermometer  and  barometer  tubes  are  drawn  in  our  glass-houses.  These  tubes 
are  chopped  into  very  small  pieces  of  nearly  uniform  length  on  the  upright  edge  of  a  fiuxed 
chisel.  These  elementary  cylinders  being  then  put  in  a  heap  into  a  mixture  of  fine  sand 
and  wood  ashes,  are  stirred  about  with  an  iron  spatula  till  their  cavities  get  filled.  This 
curious  mixture  is  now  transferred  to  an  iron  pan  suspended  over  a  moderate  fire,  and  con- 


GLASS,  COLORED.  565 

tinually  stirred  about  as  before,  whereby  the  cylindrical  bits  assume  a  smooth  rounded 
form,  so  that  when  removed  from  the  fire  and  cleared  out  in  the  bore  they  constitute  beads, 
which  are  paclced  in  casks,  and  exported  in  prodigious  quantities  to  almost  every  country. 
See  Gems,  artificial. 

The  manufacture  of  reticulated  glass,  for  which  Venice  was  equally  celebrated,  was  long 
lost ;  it  was  at  length  revived  by  Pohl,  and  the  crackle  glass  was  in  like  manner  reproduced 
by  Mr.  Apsley  Pellatt  in  1851. 

The  reticulated  glass  is  produced  by  a  kind  of  network  consisting  of  small  bubbles  of 
air  inclosed  within  the  mass,  and  ranged  in  regular  series  crossing  and  interlacing  each 
other.  To  produce  this  ornamental  appearance,  hollow  glass  cones  or  conical  tubes  are 
kept  prepared,  containing  already  this  network  arrangement  of  air  bubbles.  These  tubes 
are  made  by  arranging  a  number  of  small  glass  rods  round  a  centre,  so  as  to  form  a  cylin- 
der, and  fixing  them  in  this  position  by  melted  glass.  The  cylinder  is  then  heated  until 
the  single  rods  stick  together,  when  they  are  drawn  out  on  the  pipe  to  a  long  cone,  and 
spirally  twisted  at  the  same  time,  the  one  half  to  the  right  and  the  other  to  the  left,  when 
one  of  these  hollow  cones  is  inserted  in  the  other,  and  the  two  are  heated  until  they  fuse 
together ;  wherever  the  little  rods  cross  each  other  a  bubble  of  air  will  be  inclosed,  and 
this  occurring  in  a  very  regular  manner,  the  reticulated  appearance  is  produced.  The 
Venetians  were  also  celebrated  for  their  "  filigree."  This  glass  has  of  late  years  been  rein- 
troduced in  France  and  in  this  country.  The  process  of  manufacture  has  been  thus  de- 
scribed by  Mr.  Apsley  Pellatt,  in  his  Curiosities  of  Glass  Manufacture  : 

"  Before  ornaments  or  vessels  can  be  blown,  small  filigree  canes,  with  white  or  variously 
colored  enamels,  must  be  drawn.  These  are  first  '  whetted '  off  to  the  required  lengths,  and 
then  put  into  a  cylindrical  mould  with  suitable  internal  recesses,  and  both  cane  and  mould 
are  thus  submitted  to  a  moderate  heat.  The  selection  of  the  color  of  the  canes  depends 
upon  the  taste  of  the  manufacturer :  two  to  four  white  enamel  canes  are  chiefly  used,  alter- 
nately, with  about  half  the  number  of  colored.  The  blower  then  prepares  a  solid  ball  of 
transparent  flint  glass,  which  being  deposited  in  contact  with  the  various  canes,  at  a  welding 
heat,  occasions  them  to  adhere.  This  solid  ball  is  then  taken  from  the  mould,  is  reheated, 
and  '■marvered''  till  the  adhering  projecting  ornamental  canes  are  rubbed  into  one  uniform 
mass ;  the  ball  is  next  covered  with  a  gathering  of  white  glass,  which  must  then  be  drawn 
to  any  size  and  length  that  may  be  required.  Should  a  spiral  cane  be  preferred,  the  'pu- 
cellas'  holds  the  apex  in  a  fixed  position,  while  the  ornamental  mass,  still  adhering  to  the 
glass-maker's  iron,  is  revolved  during  the  process,  till  the  requisite  twist  is  given.  Where 
vases  are  formed  of  alternately  colored  and  enamelled  filigree  canes,  the  above  process  is 
repeated,  and  the  usual  mode  of  blowing  is  followed." 

?7te  Venetian  ball  is  a  collection  of  waste  pieces  of  filigree  glass  conglomerated  together 
without  regular  design ;  this  is  packed  into  a  pocket  of  transparent  glass,  which  is  adhe- 
sively collapsed  upon  the  interior  mass  by  sucking  up,  producing  outward  pressure  of  the 
atmosphere. 

Millefiore,  or  star  work  of  the  Venetians,  is  similar  to  the  last,  only  the  lozenges  of  glass 
are  more  regularly  placed. 

The  Vitro  di  Trino  of  the  Venetians  is  similar  to  the  filigree  in  many  respects ;  but  by 
closing  an  outer  on  the  inner  case,  each  containing  filigree  canes,  a  bubble  of  air  is  inclosed 
between  each  crossing  of  the  canes. 

The  celebrated  frosted  glass  of  the  Venetians  was  reintroduced  by  Mr.  Apsley  Pellatt,  in 
1851,  who  thus  describes  the  process  of  manufacture  :  "Frosted  glass,  like  Vitro  di  Trino, 
is  one  of  the  few  specimens  of  Venetian  work  not  previously  made  by  the  Egyptians  and 
the  Romans,  and  not  since  executed  by  the  Bohemian  or  French  glass-makers.  The  process 
of  making  it,  until  recently  practised  at  the  Falcon  Glass  Works,  was  considered  a  lost  art. 
Frosted  glass  has  irregularly  varied  marble-like  projecting  dislocations  in  its  intervening 
fissures.  Suddenly  plunging  hot  glass  into  cold  water,  produces  cry.stalline  convex  frac- 
tures, with  a  polished  exterior,  like  Derbyshire  spar ;  but  the  concave  intervening  figures 
are  eaused,  first  by  chilling,  and  then  reheating  at  the  furnace  and  simultaneously  expand- 
ing the  reheated  ball  of  glass  by  blowing,  thus  separating  the  crystals  from  each  other,  and 
leaving  open  figures  between,  which  is  done  preparatory  to  forming  vases  or  ornaments. 
Although  frosted  glass  appears  covered  with  fractures,  it  is  perfectly  sonorous." 

GLASS,  COLORED.  Most  of  the  metallic  oxides  impart  a  color  to  glass,  and  some 
non-metallic,  and  even  .some  substances  derived  from  the  organic  kingdom  have  the  power 
of  imparting  permanent  colors  to  the  vitreous  combinations  of  flint  and  potash.  There  is 
much  in  this  subject  which  still  recpiires  examination.  M.  Bontemp.s,  at  the  meeting  of  the 
British  Association  at  Birmingham,  brought  forward  some  very  extraordinary  facts  in  con- 
nection with  the  coloring  powers  of  different  bodies.  Of  his  communication  the  following 
is  an  abstract : 

In  the  first  place  it  was  shown  that  all  the  colors  of  the  prismatic  spectrum  might  be 
given  to  glass  by  the  use  of  the  oxide  of  iron  in  varying  proportions,  and  by  the  agency  of 
different  degrees  of  heat ;  the  conclusion  of  the  author  being,  that  all  the  colors  are  pro- 


566  GLASS,  COLOKED. 

duced  ill  their  natural  disposition  in  proportion  as  you  increase  the  temperature.  Similar 
phenomena  were  ol)Scrved  with  the  oxide  of  manganese.  Manganese  is  employed  to  give 
a  pink  or  purple  tint  to  glass,  and  also  to  neutralize  the  slight  green  given  by  iron  and  car- 
bon to  glass  in  its  manufacture.  If  the  glass  colored  by  manganese  remains  too  long  in  the 
melting-pot  or  the  annealing-kiln,  the  purple  tint  turns  first  to  a  light  brownish  red,  then  to 
yellow,  and  afterwards  to  green.  White  glass  in  which  a  small  proportion  of  manganese 
has  been  used,  is  liable  to  become  light  yellow  by  exposure  to  luminous  power.  This  oxide 
is  also,  in  certain  window  glass,  disposed  to  turn  pink  or  purple  under  the  action  of  the 
sun's  rays.  M.  Bontemps  has  found  that  similar  changes  take  place  in  the  annealing-oven. 
He  has  determined,  by  experiments  made  by  him  on  polygonal  lenses  for  M.  Fresnel,  that 
light  is  the  agent  producing  the  change  mentioned ;  and  the  author  expresses  a  doubt 
whether  any  change  in  the  oxidation  of  the  metal  will  explain  the  photogenic  effect.  A 
series  of  chromatic  changes  of  a  similar  character  were  observed  with  the  oxides  of  copper, 
the  colors  being  in  like  manner  regulated  by  the  heat  to  which  the  glass  was  exposed.  It 
was  found  that  silver,  although  with  less  intensity,  exhibited  the  same  phenomena ;  and 
gold,  although  usually  employed  for  the  purpose  of  imparting  varieties  of  red,  was  found 
by  varying  degrees  of  heating  at  a  high  temperature,  and  recasting  several  times,  to  give  a 
great  many  tints,  varying  from  blue  to  pink,  red,  opaque  yellow,  and  green.  Charcoal  in 
excess  in  a  mixture  of  silica-alkaline  glass  gives  a  yellow  color,  which  is  not  so  bright  as 
the  yellow  from  silver;  and  this  yellow  color  may  be  turned  to  a  dark  red  by  a  second  fire. 
The  author  is  disposed  to  refer  these  chromatic  changes  to  some  modifications  of  the  com- 
posing particles,  rather  than  to  any  chemical  changes  in  the  materials  employed. 

It  is  not  possible  in  the  present  essay  to  enter  into  the  minute  details  of  this  beautiful 
branch  of  glass  manufacture.  In  the  following  statement  the  materials  ordinarily  employed 
to  color  glass  alone  are  named : 

Yellow.  Charcoal  or  soot  is  used  for  producing  the  commoner  varieties  of  yellow 
glass. 

The  glass  of  antimony,  which  is  obtained  by  roasting  sulphide  of  antimony  until  anti- 
monious  acid  is  formed,  and  melting  it  with  about  5  per  cent,  of  undecomposed  sulphide  of 
the  same  metal. 

TJie  autimoniate  of  potash,  a  preparation  similar  to  James's  powder,  is  stated  to  answer 
the  same  purpose.  Bohemian  glass  is  colored  yellow  with  glass  of  antimony,  minium,  and 
oxide  of  iron. 

Silver  imparts  a  very  beautiful  yellow  color  to  glass,  hut  it  requires  some  caution  in  its 
mode  of  application.  It  is  believed  that  the  presence  of  alumina  is  necessary  to  the  pro- 
duction of  color,  since  a  fine  yellow' cannot  be  produced  unless  alumina  be  present.  A 
mixture  of  powdered  clay  and  chloride  of  silver  is  prepared,  and  spread  upon  the  surface  of 
the  glass ;  the  glass  is  then  reheated,  and  the  silver  penetrates  to  a  certain  depth  into  the 
glass  before  the  latter  softens.  The  coating  is  then  scraped  off,  and  the  fine  yellow  color 
appears.  If  the  silver  yellow  glass  is  held  over  the  flame  of  burning  Avood,  a  peculiar 
opalescence  is  produced  upon  the  surface,  probably  by  the  oxidation  of  the  silver. 

Uranium  produces  the  beautiful  canary  yellow  which  is  found  in  many  articles  of  an 
ornamental  kind.  This  glass  possesses  the  very  peculiar  property  of  giving  a  green  color 
when  it  is  looked  at,  although  perfectly  and  purely  yellow  when  looked  throvgh.  This  has 
been  attributed  to  the  presence  of  iron  in  the  commercial  oxide  of  uranium  employed ;  but 
the  purer  the  uranium  is,  the  more  Ijcautifully  will  this  phenomenon  be  brought  out.  It 
depends  upon  a  very  remarkable  physical  peculiarity  belonging  to  uranium  and  some  other 
bodies. 

Red.  a  common  l)rownish  red  color  is  produced  in  glass  by  oxide  of  iron,  added  as 
ochre,  or  in  the  state  of  pure  peroxide.  MuUer  found  ancient  red  glass  to  contain  silicic 
acid,  alkalies,  lime,  magnesia,  alumina,  protoxide  of  iron,  and  suboxide  of  copper. 

Copper  is  more  generally  employed  in  coloring  glass  red.  The  use  of  this  metal  for  this 
purpose  dates  from  very  high  antiquity,  and  all  through  the  middle  ages  it  was  employed 
to  produce  the  reds  which  we  see  in  the  fine  old  windows  left  by  our  ancestors  for  oup  ad- 
miration. The  ancient  Ilmnatinone  was  a  copper  red  glass.  Suboxide  of  copper  is  used, 
either  in  the  state  of  commercial  copper  scale,  or  it  is  prepared  by  heating  copper  turnings 
to  redness.  If,  during  the  fusion  of  the  glass  in  the  pot,  the  sul)Oxide  unites  with  an  addi- 
tional quantity  of  oxygen,  green  and  not  red  is  the  result.  This  is  avoided  by  combining 
some  reducing  agent  with  the  melted  sulistance.  Glass  thus  colored  does  not  exhiljit  its 
red  color  on  leaving  the  crucilile ;  it  is  nearly  colorless,  or  with  a  tinge  of  green  even  when 
cold ;  but  if  it  is  then  heated  a  second  time  it  assumes  the  red  color.  II.  Rose  supposes 
that  a  colorless  neutral  or  acid  silicate  of  the  sulioxide  of  copper  is  formed  at  a  high  tem- 
perature, and  that  the  subse(iuent  softening  of  the  gla.ss  at  a  lower  temperature  causes  the 
decomposition  of  this  compound  and  a  separation  of  a  portion  of  the  suboxide.  We  believe 
that  no  such  chemical  change  takes  place,  and  that  the  alteration  is  due  merely  to  a  change 
in  the  molecular  arrangement  of  the  particles.  The  suboxide  of  copper  possesses  an  intense 
coloring  power — so  great,  indeed,  that  glass  colored  with  even  a  very  small  quantity  is  al- 


GLUCINUM. 


567 


most  impermeable  to  light ;  hence  it  is  usual  merely  to  flash  colorless  glass  with  this  col- 
ored glass,  that  is,  to  spread  a  very  thin  film  of  it  over  the  colorless  surface.  A  process 
for  coloring  glass  red  after  its  manufacture  with  sulphide  of  copper  has  been  introduced  by 
Bedford. 

Gold  can,  according  to  circumstances,  be  made  to  impart  a  ruby,  carmine,  or  pink  tint 
to  glass.  The  purple  of  Cassius  was  employed,  but  Dr.  Fus.s  first  showed  that  a  mere  solu- 
tion of  gold  without  the  presence  of  tin,  as  in  the  salt  named,  is  capable  of  producing  rose 
and  carmine  colored  glass. 

Similar  changes  to  those  already  described  with  copper  occur  with  the  salts  of  gold. 
Perhaps  the  glass  is  colorless  in  the  pot,  and  it  then  remains  colorless  when  cold ;  but  when 
reheated,  the  glass  quickly  assumes  a  light  red  color,  which  rapidly  spreads  from  the  heated 
point  over  the  whole  glass,  and  increases  in  intensity  until  it  becomes  nearly  a  black  red. 
This  colored  glass  can  be  again  rendered  colorless  by  fusion  and  slow  cooling ;  its  color  is 
again  produced  by  a  repetition  of  the  heating  process.  If,  however,  it  is  suddenly  cooled 
it  cannot  again  be  made  to  resume  its  ruby  color.  This  is  also  an  example  confirmatory  in 
the  highest  degree  of  the  view  that  no  chemical  change  takes  place,  but  that  all  the  phe- 
nomena are  due  to  alterations  in  molecular  structure.  The  practice  oi  flashing  color- 
less glass  with  the  ruby  glass  from  gold  is  commonly  adopted.  The  beautiful  examples  of 
the  Bohemian  glass  manufacture,  in  which  we  have  a  mixture  of  rich  ruby  and  the  purest 
crystal,  are  produced  in  this  way :  a  globe  of  hot  colorless  glass  is  taken  from  the  pot,  and 
a  cake  of  ruby  glass,  prepared  with  a  composition  called  schmebze,  is  warmed  and  brought 
into  contact  with  the  melted  globe ;  this  ruby  glass  rapidly  diffuses  itself  over  the  surface, 
and  the  required  article  is  blown  or  moulded  with  a  coating  of  glass,  colored  ruby  by  gold, 
of  any  required  tliickness. 

Schmebze  is  prepared  with  500  parts  of  silica,  800  of  minium,  100  of  nitre,  and  the 
same  quantity  of  potash.  A  very  small  portion  of  a  solution  of  gold  in  aqtia  regia  is  inti- 
mately mixed  with  500  parts  of  schmebze,  43  parts  of  prismatic  borax,  3  or  4  of  oxide  of 
tin,  and  a  similar  quantity  of  oxide  of  antimony.  This  mixture  is  heated  for  twelve  hours 
in  an  open  crucible  placed  in  a  flat  furnace,  and  then  cooled  slowly  in  an  annealing-oven. 
A  Bohemian  ritbi/,  especially  so  called,  is  prepared  by  melting  together  fulminating  gold 
rubbed  in  with  oil  of  turpentine,  quartz  powdered,  and  fritted  minium,  sulphide  of  antimo- 
ny, peroxide  of  manganese,  and  potash.  Biihme  has  given  an  analysis  of  a  Venetian  ruby 
glass,  in  which  .05  of  a  grain  of  gold  is  combined  with  about  150  of  the  ordinary  ingredients 
of  glass,  with  some  tin  and  iron. 

Manganese  is  sometimes  employed  to  give  a  fine  amethystine  color  to  glass ;  care  is, 
however,  required  to  prevent  the  reduction  of  the  peroxide  of  manganese  in  the  process. 

Green.  Green  colors  may  be  obtained  by  a  variety  of  metallic  oxides.  Protoxide  of 
iron  imparts  a  dull  green ;  an  emerald  green  color  is  given  by  oxide  of  copper.  Either 
copper  scales  or  verdigris  dried  and  powdered  are  employed,  the  color  being  much  finer 
with  a  lead  glass  than  with  one  containing  no  lead.  Translucent  or  dull  glass  is  converted 
into  a  deep  blue  or  turquoise  color  by  oxide  of  copper,  and  not  into  a  green.  An  emerald 
green  is  also  produced  by  the  oxide  of  chromium.  Two  kinds  of  Bohemian  green  glass, 
known  respectively  as  the  ancient  and  modern  emerald  greens,  are  prepared  from  mixtures 
of  the  oxides  of  nickel  and  of  uranium. 

Blue.     The  only  fine  blue  is  produced  by  cobalt.     See  Azure  and  Cobalt,  vol.  i. 

Brown.     Peroxide  of  manganese  with  zaffre  yields  a  fine  garnet-like  brown. 

Pink  or  Flesh  Color.  Oxide  of  iron  and  alumina,  obtained  by  heating  a  mixture  of 
alum  and  green  vitriol. 

Orange.     Peroxide  of  iron  with  chloride  of  silver. 

Jasper.  A  Bohemian  glass,  generally  black,  but  of  fine  lustre,  prepared  by  adding 
forge  scales,  charcoal,  and  bone  ashes  to  the  ordinary  materials  for  glass. 

GLUCINCiL  The  metal  of  Glucina  has  been  obtained  by  M.  H.  Debray  {Ann.  Chym. 
et  Phi/s.  xliv.  5)  by  the  following  process :  Into  a  wide  glass  tube  are  introduced  two  ves- 
sels, one  containing  chloride  of  glucinum,  and  the  other  sodium,  deprived  of  the  greatest 
part  of  the  adhering  naphtha  by  compression  between  two  sheets  of  blotting  paper.  Tiie 
glass  tube  is  placed  in  a  combustion  furnace.  It  is  then  traversed  by  a  current  of  hydro- 
gen, passing  from  the  chloride  of  glucinum  to  the  sodium.  The  sodium  is  not  placed  in 
the  tube  until  all  the  air  has  been  expelled  by  the  hydrogen.  The  tube  is  then  heated  just 
where  the  sodium  is  placed,  which  by  this  means  is  deprived  of  the  last  particles  of  naph- 
tha, and  fuses.  The  chloride  of  glucinum  is  then  heated.  The  vapor  of  cliloride,  driven 
forward  by  the  hydrogen,  arrives  over  the  fused  sodium.  It  then  swells  up,  and  the  heat 
generated  by  chemical  action  is  sufficient  to  raise  the  contents  of  the  vessel  to  redness, 
which  often  breaks  the  vessel  if  made  of  porcelain.  The  operation  is  ended  when  the  chlo- 
ride of  glucinum  sublimes  beyond  the  sodium  vessel.  When  the  tube  is  cool  the  vessel  is 
withdrawn,  and  in  the  place  of  the  sodium  a  large  quantity  of  a  blackish  substance  is  found, 
composed  of  common  salt  and  the  metal  glucinum  in  brilliant  spangles,  and  sometimes  even 


568  GLUOINUM. 

in  globules.  This  mass  is  quickly  detached  and  fused  in  a  small  crucible,  with  the  addition 
of  some  dried  common  salt,  which  acts  as  a  flux,  and  facilitates  the  union  of  the  globules 
of  metal. 

It  is  a  white  metal,  whose  density  is  2"1.  It  may  be  forged  and  rolled  into  sheets  like 
gold.  Its  melting  point  is  inferior  to  that  of  silver.  It  may  be  melted  in  the  outer  blow- 
pipe flame,  without  exhibiting  the  phenomenon  of  ignition  presented  l)y  zinc  and  iron  »mder 
the  same  circumstances.  It  cannot  l>e  set  on  fire  in  an  atmosphere  of  pure  oxj-gen,  but  in 
lioth  cases  is  covered  with  a  film  of  oxide,  which  seems  to  protect  it  from  further  action. 
It  is  not  acted  cm  by  sulphur,  but  readily  combines  with  chlorine  and  iodine  by  the  aid  of 
heat. 

Silicium  unites  readily  with  it,  forming  a  hard,  brittle  substance,  capable  of  taking  a 
high  polish.  This  substance  is  always  formed  when  glucinum  is  prepared  in  porcelain  ves- 
sels, the  silica  being  reduced  by  this  metal.  After  several  fusions  in  such  vessels,  glucinum 
may  contain  as  much  as  20  per  cent,  of  silicium.  Glucinum  does  not  decompose  water  at 
the  temperature  of  ebullition,  nor  even  at  a  white  heat. 

Sulphuric  and  hydrochloric  acids  dissolve  it  easily,  either  concentrated  or  diluted,  with 
the  evolution  of  hydrogen. 

Nitric  acid,  even  when  concentrated,  has,  at  ordinary  temperatures,  no  action  upon  it, 
and  dissolves  it  but  slowly  when  boiling. 

Glucinum,  though  not  acted  on  by  ammonia,  dissolves  readily  in  caustic  potash. 

The  metal  which  Wohler  obtained,  by  igniting  chloride  of  glucinum  with  potassium  in 
a  platinum  crucible,  diflers  considerably  from  that  just  described,  the  metal  thus  obtained 
being  a  gray  powder,  very  refractory  in  the  furnace,  but  combines  with  oxygen,  chlorine, 
and  sulphur  much  more  energetically  than  the  metal  described  by  Debray.  The  difierences 
arise  probably  partly  from  the  difTerent  state  of  aggregation,  and  partly  from  the  contami- 
nation of  Wohler's  metal  with  platinum  and  potassium. 

Berzelius  effected  the  solution  of  the  beryl  by  fusing  the  finely-powdered  beryl  with 
three  times  its  weight  of  carbonate  of  potash  in  a  platinum  crucible,  and  then  treating  the 
fused  mass  with  hydrochloric  acid ;  but  the  swelling  up  of  the  mixture  of  carbonate  of  pot- 
ash and  beryl  at  the  moment  of  fusion,  prevents  large  quantities  being  made  at  a  time. 
To  obviate  this,  Debray  uses  lime.     The  following  is  the  process  given  by  him : 

The  pulverized  emerald  is  mixed  with  half  its  weight  of  quicklime  in  powder ;  the  mix- 
ture is  then  fused  in  an  earthen  crucible  placed  in  a  wind-furnace ;  the  temperature  at 
which  the  fusion  takes  place  is  much  lower  than  that  required  for  the  assay  of  iron.  The 
glass  thus  obtained  is  powdered  and  moistened  with  water  acidulated  with  nitric  acid,  so  as 
to  obtain  a  thick  paste,  to  which  is  added  concentrated  nitric  acid,  taking  care  to  stir  the 
mass,  which  is  converted,  in  the  cold,  but  better  by  heat,  into  a  homogeneous  jelly ;  this  is 
evaporated  to  drive  off"  the  excess  of  acid,  then  heated  so  as  to  decompose  the  nitrates  of 
alumina,  glueina,  and  iron.  It  is  advisable  to  raise  the  temperature  at  the  end  of  the  oper- 
ation so  as  to  decompose  a  small  portion  of  the  nitrate  of  lime.  The  result  of  this  calci- 
nation is  composed  of  insoluble  silica,  alumina,  glueina,  and  sesquioxide  of  iron,  insoluble 
in  water,  finally,  nitrate  of  lime,  and  a  little  free  lime.  It  is  boiled  with  water  containing 
Eome  chloride  of  ammonium. 

The  nitrate  of  lime  is  rapidly  removed  by  the  water,  and  the  lime  decomposing  the 
chloride  of  ammonium  is  also  at  length  dissolved,  with  liberation  of  ammonia.  This  disen- 
gagement of  ammonia  ceases  as  soon  as  all  the  lime  is  dissolved,  and  as  it  is  the  surest 
guarantee  of  the  non-solution  of  the  alumina  and  glueina,  the  calcination  of  the  nitrates 
should  be  repeated,  unless  ammonia  is  liberated  under  the  circumstances  just  mentioned. 
The  residue  of  silica,  alumina,  glueina,  and  iron  is  well  washed  until  all  the  lime  is  re- 
moved, which  is  known  by  oxalate  of  ammonia  causing  no  cloudiness  in  the  washings. 
The  separation  of  the  silica  and  the  earths  is  easily  effected,  mere  boiling  with  nitric  acid 
dissolving  the  alumina,  glueina,  and  iron,  and  leaving  the  silica  undissolved.  The  solution 
of  the  nitrates  of  alumina,  glueina,  and  iron  is  then  poured  into  a  solution  of  carbonate  of 
ammonia,  to  which  a  little  ammonia  has  been  added.  The  precipitation  of  the  earths  takes 
place  witiiout  liberation  of  carbonic  acid,  and  the  glueina  at  length  redissolves  in  the  car- 
bonate of  ammonia.  The  solution  of  the  glueina  may  be  considered  complete  after  seven 
or  eight  days'  digestion.  As  the  carbonate  of  ammonia  may  dissolve  a  little  iron,  it  is  better 
to  add  to  the  solution  a  few  drops  of  sulphide  of  ammonium,  which  precipitates  it  com- 
pletely. The  solution  is  then  filtered  and  boiled  to  drive  off  the  carbonate  of  ammonia, 
when  the  glueina  is  precipitated  in  the  state  of  carbonate. 

The  carl)onate  of  glueina  is  a  dense  white  powder,  easily  washed ;  it  is  collected  on  a 
filter  and  dried. 

From  the  carbonate  any  of  the  other  compounds  of  glueina  may  be  easily  prepared ; 
simple  calcination  converts  it  into  glueina.  A  process  for  the  separation  of  alumina  and 
glueina  has  been  proposed  by  M.  Berthier;  it  consists  in  suspending  the  well-washed  earths 
in  water,  and  passing  a  current  of  sulphurous  acid  through  them.  Their  solution  is  com- 
plete.    The  liquid  is  then  boiled  to  expel  the  excess  of  sulphurous  acid,  when  a  dcns'^  ?ub- 


GLUCINUM. 


569 


sulphite  of  alumina  is  precipitated,  leaving  the  glucina  in  solution.     Debray  found  that 
sometimes  in  this  process  the  glucina  wa,s  entirely  precipitated  with  the  alumina. 
Glucina  thus  obtained  possesses  the  following  properties: 

It  is  a  light  white  powder,  without  smell  or  taste — infusible,  but  volatilizes  just  as  zinc 
and  magnesia.  Heat  does  not  harden  glucina  as  it  does  alumina,  but  renders  it  nevertheless 
insoluble  in  acids.  Boiling  concentrated  sulphuric  acid  dissolves  it  easily,  but  the  action  of 
nitric  acid  is  very  feeble  when  the  glucina  has  been  .strongly  heated.  Caustic  potash  dis- 
solves it  readily ;  and  glucina  is  even  capable  of  expelling  the  carbonic  acid  from  carbonate 
of  potash ;  it  is  again  precipitated  from  its  solution  in  potash  by  boiling  when  diluted  to  a 
certain  extent. 

Ebelmen  has  obtained  it  in  hexagonal  prisms  by  submitting  a  solution  of  glucina,  in 
fused  boracic  acid,  to  a  powerful  and  long-continued  heat.  It  may  likewise  be  obtained  in 
microscopic  crystals  by  a  more  easy  process,  which  consists  in  decomposing  the  sulphate  of 
glucina  at  a  high  temperature,  in  the  presence  of  sulphate  of  potash ;  also  by  calcining  the 
double  carbonate  of  glucina  and  ammonia.  The  crystals  are  separated  from  the  sulphate  of 
potash  by  washing. 

The  hydrate  of  glucina  is  obtained  by  precipitating  a  salt  of  that  base  by  ammonia. 
The  presence  of  ammoniacal  salts  does  not  hinder  the  precipitation.  When  recently  pre- 
pared it  greatly  resembles  the  hydrate  of  alumina,  only  it  absorbs,  by  drying  in  the  air,  a 
notable  fiuantity  of  carbonic  acid. 

The  hydrate  of  glucina  easily  loses  its  water  by  heat,  and  becomes  then  insoluble  in  car- 
bonate of  ammonia,  the  hydrate  when  pure  being  very  soluble  in  it ;  but  its  solution  is  hin- 
dered by  the  presence  of  alumina,  in  which  case  it  is  only  complete  after  several  hours' 
digestion.     It  is  also  soluble  in  sulphurous  acid  and  bisulphite  of  ammonia. 

Glucina  precipitated  from  some  of  its  solutions  by  ammoniii„  is  rcdissolved  by  prolonged 
ebullition,  but  this  is  observed  more  especially  when  precipitated  from  the  oxalate  or  ace- 
tate of  glucina. 

Chloride',  of  glucinum  is  prepared  by  the  same  process  as  the  chloride  of  aluminium, 
merely  substituting  glucina  for  alumina,  and  at  first  sight  very  much  resembles  it ;  it  is, 
however,  much  less  volatile  than  chloride  of  aluminium,  being  about  as  volatile  as  chloride 
of  zinc.  It  differs  also  from  chloride  of  aluminium  inasmuch  as  it  is  not  capable  of  forming 
definite  compounds  with  some  protochlorides ;  chloride  of  aluminium  uniting  with  certain 
protochlorides  forming  a  series  of  compounds,  fusible  at  a  low  temperature,  volatile  at  a 
red  heat  without  decomposition ;  and  the  composition  of  which  is  represented  by  the  for- 
mula APCl'-f  MCI.  The  crystals  of  chloride  of  aluminium  may  be  called  chlorinated  spi- 
nelles,  and  are  easily  obtained,  it  being  only  necessary,  in  order  to  form  the  sodium  com- 
pound of  the  group,  to  mix  the  chloride  of  aluminium  with  half  its  weight  of  common  salt, 
and  distil,  one  distillation  producing  it  pure,  the  formula  of  it  being  APCP-f-XaCl.  Chlo- 
ride of  glucinum  is  very  soluble  in  water ;  it  may,  however,  be  obtained  in  crystals,  by 
allowing  its  solution  to  evaporate  over  sulphuric  acid  under  a  bell  jar.  The  presence  of  a 
little  free  hydrochloric  acid  favors  the  crystallization.  Thus  obtained,  this  salt  is  a  hydrate, 
and  according  to  Awdejew  its  formula  is  GlCl-i-4110.  The  hydrated  chloride  of  glucinum 
is  decomposed  by  heat  into  hydrochloric  acid  and  glucina. 

Iodide  of  glucinum. — This  compound  presents  all  the  characters  of  the  chloride,  only 
being  a  little  less  volatile.  The  affinity  of  iodine  for  glucinum  is  not  very  strong,  oxygen 
decomposing  the  iodide  at  the  heat  of  a  spirit  lamp,  liberating  iodine  and  forming  glucina. 
Glucinum  is  also  capable  of  combining  with  fluorine,  the  double  fluoride  of  glucinum 
and  potassium  being  formed  by  pouring  a  solution  of  fluoride  of  potassium  into  a  salt  of 
glucina.  It  is  but  little  soluble  in  the  cold,  and  is  deposited  in  the  form  of  brilliant  scales. 
Sulphate  of  glucina. — This  salt  is  white,  has  an  acid  and  slightly  sweet  taste.  It  is  un- 
alterable in  the  air  at  ordinary  temperatures,  but  effloresces  in  dry  and  warm  air.  By  heat 
it  first  fuses,  in  its  water  of  crystallization,  then  at  a  red  heat  is  decomposed  into  sulphurous 
acid,  oxygen,  and  glucina. 

Water  at  57*2'''  F.  (14"  C.)  dissolves  about  its  own  weight  of  this  salt;  its  solubility  is 
increased  by  heat,  and  boiling  water  dissolves  an  indefinite  quantity.  The  presence  of  free 
sulphuric  acid  or  alcohol  lessens  its  solubihty. . 

It  loses  a  portion  of  its  acid  in  many  cases  with  facility ;  for  instance  we  obtain  an  un- 
crystallizable  tribasic  sulphate  of  glucina,  by  dissolving  carbonate  of  glucina  in  a  concen- 
trated solution  of  the  sulphate ;  carbonate  of  glucina  is  added  until  carbonic  acid  ceases  to 
be  liberated  at  each  addition ;  the  liquid,  filtered  and  evaporated,  gives  a  gummy  residue. 
The  very  dilute  solution  of  this  salt  lets  fall  some  glucina,  and  is  changed  into  a  bibasic  sul- 
phate, also  uncrystallizable. 

Sulphate  of  glucina  dissolves  zinc  with  disengagement  of  hydrogen,  forming  a  bibasic 
sulphate  of  glucina  and  sulphate  of  zinc.  Sulphate  of  alumina,  under  the  same  circum- 
stances, dissolves  zinc  with  liberation  of  hydrogen,  and  forms  a  sulphate  of  zinc  and  an 
insoluble  subsulphate  of  alumina.  Taking  advantage  of  this  difference,  Debray  proposed  a 
method  {Ann.   Chijm.  et  Phys.   xliv.  20)  for  the  separation  of  alumina  and  glucina,  but 


570  GLYCERINE. 

which  does  not  answer  for  analytical  purposes,  as  chemically  pure  zinc  is  only  acted  on  with 
great  difficulty  by  these  sulphates.  Sulphate  of  glucina  is  formed  by  dissolving  the  carbon- 
ate in  dilute  sulphuric  acid,  the  evaporated  liquid  depositing  it  on  cooling.  It  is  essential 
to  keep  the  liquid  distinctly  acid ;  it  assists  the  crystallization,  and  besides,  if  we  were  to 
dissolve  the  carbonate  m  it  until  the  liberation  of  carbonic  acid  ceased,  we  should  obtain  a 
basic  uncrystallizable  salt.     According  to  Awdcjew  the  formula  of  this  salt  is 

G10,S0=  +  4H0. 

Double  snlphate  of  glucina  and  potash. — This  salt  was  discovered  by  Awdejew  ;  he  ob- 
tained it  while  endeavoring  to  produce  the  double  sulphate  of  glucina  and  potash  corre- 
sponding to  common  alum,  (which,  had  he  succeeded,  would  have  been  one  of  the  best 
proofs  of  the  analogy  existing  between  alumina  and  glucina.) 

It  is  obtained  in  crystalline  crusts,  by  evaporating  a  solution  containing  15  parts  of 
sulphate  of  glucina  to  14  parts  of  sulphate  of  potash.  The  concentration  is  stopped  as 
soon  as  the  liquid  becomes  turbid  ;  at  the  end  of  a  few  hours  this  salt  is  deposited,  which 
is  purified  by  recrystallization.  It  is  precipitated  as  a  crystalline  powder  by  the  addition  of 
sulphuric  acid  to  the  concentrated  solution.  It  is  but  little  soluble  in  the  cold,  much  more 
so,  though  slowly,  in  hot  water.  By  the  action  of  heat  it  finst  fuses  in  its  water  of  crystal- 
lization, then  is  decomposed  entirely  into  glucina  and  sulphate  of  potash,  if  the  heat  is 
strong  and  long  enough  applied.  Its  composition  is  represented  by  the  formula 
G10,S0'-fK0,S0V2H0. 

Carbonate  of  glucina. — Glucina  is  soluble  in  carbonate  of  ammonia.  When  the  solution 
is  boiled,  carbonate  of  ammonia  is  driven  off,  and  a  precipitate  of  carbonate  of  glucina  is 
formed,  the  composition  of  which  seems  to  be 

3G10,COV5HO; 
but  if  we  arrest  the  boiling  as  soon  as  the  solution  becomes  turbid,  we  obtain  a  solution  of 
a  double  carbonate  of  glucina  and  ammonia,  from  which,  by  the  addition  of  alcohol,  this 
salt  is  deposited  in  clear  crystals.  Double  carbonate  of  ghtcina  and  cmunonia  is  white,  very 
soluble  in  cold  water,  but  is  easily  decomposed  by  hot  water,  liberating  carbonate  of  ammo- 
nia and  depositing  carbonate  of  glucina.  It  is  much  less  soluble  in  dilute  alcohol,  and 
nearly  insoluble  in  absolute  alcohol.  It  is  easily  decomposed  by  heat,  leaving  as  a  residue 
pure  glucina. 

It  is  also  decomposed  by  exposure  to  the  air  after  some  time.  According  to  Debray  the 
formula  of  this  salt  is 

4G10,3CO-HO  +  3(NIP0,C0^). 

There  also  exists  a  double  carbonate  of  potash  and  glucina  corresponding  to  this  salt, 
and  is  prepared  by  the  same  process,  merely  substituting  carbonate  of  potash  for  carbonate 
of  ammonia ;  the  carbonate  of  potash,  however,  takes  longer  to  dissolve  the  glucina  than 
carbonate  of  ammonia. 

Oxalic  acid  dissolves  glucina,  but  does  not  yield  any  crystallizable  compounds,  except  in 
combination  with  other  oxalates,  as  the  oxalate  of  pota.sh  or  ammonia. 

These  double  salts  crystallize  well  and  have  the  following  simple  composition : 
G10,C'05-hK0,C=0'; 
G10,CW4-NirO,C='Ol 

These  salts  are  obtained  by  dissolving  carbonate  of  glucina  in  binoxalate  of  ammonia  or 
potash  in  the  cold,  until  carbonic  acid  ceases  to  be  given  off.  They  decrepitate  by  the  ap- 
plication of  heat.  The  composition  of  glucina  is  still  undecided  ;  Berzelius  regarding  it  as 
a  sesquioxide,  and  Awdejew  and  others  as  a  protoxide.  The  latter  view  gives  greater  sim- 
plicity in  the  formula  of  its  compounds,  but  glucina  has  no  decided  analogy  to  the  ordinary 
class  of  protoxides,  lime  and  magnesia,  &c. — H.  K.  B. 

GLYCERINE.  Glycerine  is  one  of  the  products  of  the  saponification  of  fat  oils.  It  is 
produced  in  large  quantities  in  the  soap  manufactories  in  a  very  impure  state,  being  con- 
taminated with  saline  and  empyreumatic  matters,  and  having  a  very  strong  disagreeable 
odor.  In  order  to  obtain  glycerine  from  this  source,  the  residuary  liquors  are  evaporated 
and  treated  with  alcohol,  which  dissolves  out  the  glycerine.  The  alcohol  having  been  sep- 
arated by  evaporation,  the  glycerine  is  diluted  with  water,  and  boiled  with  animal  charcoal. 
This  process  must  be  repeated  several  times,  or  until  the  result  is  sufficiently  free  from 
smell.  It  is,  however,  difficult  to  obtain  pure  glycerine  from  this  source,  on  account  of  the 
nature  and  condition  of  the  ingredients  usually  employed  in  making  soap,  which  it  is  almost 
impossible  to  deprive  of  rancid  odor. 

The  compounds  of  glycerine  with  the  fatty  acids  constitute  the  various  kinds  of  fats  and 
oils,  but  the  base  does  not  appear  to  have  the  same  composition  in  all.  A  certain  quantity 
of  water  appears  to  separate,  and  the  equivalent  of  glycerine  to  be  in  some  fats  but  halt 
what  it  is  in  others.  Thus  the  glycerine  of  the  palm  oil  has  the  formula  C^H^O*,  and  the 
glycerine  of  myristine,  or  nutmeg  butter,  CH^'O,  of  which  bodies  the  common  glycerine 
should  be  the  hydrate. 


GOLD. 


571 


Glycerine  is  now  obtained  in  great  quantities  from  palm  oil,  in  the  process  of  purification 
for  candles.  It  is  employed  with  much  advantage  to  preserve  soft-bodied  animals.  It 
is  manufactured  into  soap,  is  administered  internally,  and  is  supposed  to  possess  highly 
nutritive  properties.  It  has  been  employed  in  cases  of  deafness,  and  in  diseases  of  the 
throat.  By  some  it  is  used  to  preserve  collodion  plates  in  a  state  of  sensitiveness  for 
many  days. 

GNEISS  may  be  called  stratified,  or,  by  those  who  object  to  that  term,  foliated 
granite,  being  formed  of  the  same  materials  as  granite,  namely,  felspar,  quartz,  and 
mica. — Lyell. 

Gneiss  might,  indeed,  in  its  purest  and  most  typical  form,  be  termed  schistose  granite, 
consisting,  liiie  granite,  of  felspar,  quartz,  and  mica  ;  but  having  those  minerals  arranged  in 
layers  or  plates,  rather  than  in  a  confused  aggregation  of  crystals. — Jukes. 

In  whatever  state  of  aggregation  the  particles  of  gneiss  may  have  been  originally  de- 
posited, we  know  now  that  it  is  a  hard,  tough,  crystalline  rock,  exhibiting  curved  and 
twisted  lines  of  stratification,  and  composed  in  the  main  of  quartz,  felspar,  mica,  and  horn- 
blende. Mineralogically  speaking,  it  differs  from  the  granite  rocks  with  which  it  is  asso- 
ciated chiefly  in  this,  that  while  the  crystals  of  quartz,  felspar,  &c.,  are  distinct  and  entire  in 
granite,  in  gneiss  they  are  broken,  water-worn,  and  confusedly  aggregated.  Hence  the  gen- 
eral belief  is,  that  gneiss  or  gneissose  rocks,  are  but  the  particles  of  granite  weathered 
and  worn,  carried  down  by 'streams  and  rivers,  and  deposited  in  the  seas  of  that  early 
period. — Paqe. 

GOBELIN  MANUFACTORY.  This  establishment,  which  has  been  long  celebrated  for 
its  tapestry,  took  its  name  from  the  brothers  Gobelin.  Giles  Gobelin,  a  d3-er  at  Paris,  in 
the  time  of  Francis  I.,  had  found  out  an  improvement  in  the  then  usual  scarlet  dye  ;  and  as 
he  had  remarked  that  the  water  of  the  rivulet  Bievre,  in  the  suburbs  of  St.  Marceau,  was 
excellent  for  his  art,  he  erected  on  it  a  large  dye  house,  which,  out  of  ridicule,  was  called 
Folie  Gobelins,  (Rabelais.)  About  this  period  a  Flemish  painter,  whom  some  name  Peter 
Koek,  and  others  Kloek,  and  who  had  travelled  a  long  time  in  the  East,  established,  and 
continued  to  his  death  in  1550,  a  manufactory  for  dyeing  scarlet  cloth  by  an  improved  pro- 
cess. Through  the  means  of  Colbert,  minister  of  Louis  XIV.,  one  of  the  Gobelins  learned 
the  process  used  for  preparing  the  German  scarlet  dye  from  one  Gluck,  whom  some  con- 
sider to  be  Gulich,  (who  was  said  to  have  learned  to  dye  scarlet  from  one  KufTelar,  a  dyer 
at  Leyden,)  and  others  as  Kloek  ;  and  the  Parisian  scarlet  dye  soon  rose  into  so  great  re- 
pute that  the  populace  imagined  that  Gobelin  had  acquired  the  art  from  the  devil.  It  is 
known  that  Louis  XIV.,  by  the  advice  of  Colbert,  purchased  Gobelin's  building  from  his 
successors  in  1667,  and  transformed  it  into  a  palace,  to  which  he  gave  the  name  of  Hotel 
Royal  des  Gobelins,  and  which  he  assigned  for  the  use  of  first-rate  artists,  particularly 
painters,  jewellers,  weavers  of  tapestry,  and  others. — Beckmann. 

The  national  manufactory  is  now  alone  remarkable  for  its  production  in  textile  manu- 
facture of  some  of  the  finest  works  of  art  ;  and  not  only  does  it  excel  in  the'high  character 
of  its  designs,  but  also  in  the  brilliancy  and  permanence  of  its  colors. 

GOLD.  The  mineral  formations  in  which  this  metal  occurs  are  the  crystalline  primitive 
rocks,  the  compact  transition  rocks,  the  trachytic  and  trap  rocks,  and  alluvial  grounds. 
Sir  Roderick  Murchisou  says,  in  his  chapter  0)i  the  Original  Formation  of  Gold,  in  his 
"Siluria":  "We  may  first  proceed  to  consider  the  nature  and  limits  of  the  rich  gold- 
bearing  rocks,  and  then  offer  proofs,  that  the  chief  auriferous  wealth,  as  derived  from  them, 
occurs  in  superficial  detritus.  Appealing  to  the  structure  of  the  different  mountains,  which 
at  former  periods  have  afforded,  or  still  afford,  any  notable  amount  of  gold,  we  find  in  all 
a  general  agreement.  Whether  referring  to  past  history,  we  cast  our  eyes  to  the  countries 
watered  by  the  sources  of  the  Golden  Tagus,  to  the  Phrygia  and  Thrace  of  the  Greeks  and 
Romans,  to  the  Bohemia  of  the  Middle  Ages,  to  tracts  in  Britain  which  were  worked  in  old 
times,  and  are  now  either  abandoned,  or  very  slightly  productive,  or  to  those  chains 
in  America  or  Australia  which,  previously  unsearched,  have  in  our  times  proved  so  rich, 
we  invariably  find  the  same  constants  in  nature.  In  all  these  lands,  gold  has  been  imijarted 
abundantly  to  the  ancient  rocks  only,  whose  order  and  succession  we  have  traced,  or  their 
associated  eruptive  rocks.  Sometimes,  however,  it  is  also  shown  to  be  diffused  through  the 
body  of  such  rocks,  whether  of  igneous  or  of  aqueous  origin.  The  stratified  rocks  of  the 
highest  antiquity,  such  as  the  oldest  gneiss  and  quartz  rocks,  (like  those,  for  example,  of 
Scandinavia  and  the  northern  Highlands  of  Scotland,)  have  very  seldom  borne  gold,;  but 
the  sedimentary  accumulations  which  followed,  or  the  Silurian,  Devonian,  and  carboniferous, 
(particularly  the  first  of  these  three,)  have  been  the  deposits  which,  in  tlie  tracts  where  they 
have  undergone  a  metamorphosis  or  change  of  structure  f)y  the  influence  of  igneous  agency, 
or  other  causes,  have  been  the  chief  now ws,  whence  gold  has  been  derived." 

At  the  Soimanofsk  mines,  south  of  Miask,  great  piles  of  ancient  drift  or  gravel  having 
been  removed  for  the  extraction  of  gold,  the  eroded  edges  of  highly  inclined  crystalline 
limestones  have  been  exposed,  wliich  from  being  much  nearer  the  centre  of  the  chain  than 
the  above,  are  probably  of  Silurian  or  Devonian  age.     It  is  from  the  adjacent  eruptive 


)72 


GOLD. 


serpentinous  masses  and  slaty  rocks  b  that  the  gold  shingle  c  (usually  most  auriferous  near 
the  surface  of  the  abraded  rock  a)  has  been  derived.  The  tops  of  the  highly  inclined  beds 
a  are  in  fact  rounded  off,  and  the  interstices  between  them  worn  into  holes  and  cavities,  as 


812 


■■'-  "^i^rtiiij 

l1llli)lllM 

11:5.1  lllL'illl! 

llll>IK\Uli  i>> 

ill.!AUUI  \ni 


if  by  very  powerful  action  of  water.  Now  here,  as  at  Berezovsk,  mammoth  remains  have 
been  found.  They  were  lodged  in  the  lowest  part  of  the  excavation,  at  the  spot  marked 
wi,  and  at  about  fifty  feet  beneath  the  original  surface  of  overlying  coarse  gravel  c,  before 
it  was  removed  by  the  workmen  from  the  vacant  space  under  the  dotted  line.  The  feeble 
influence  of  the  streams  (n)  which  now  flow,  in  excavating  even  the  loose  shingle,  is  seen 
at  the  spot  marked  o,  the  bed  of  the  rivulet  having  been  lowered  by  human  labor  from 
its  natural  level  o  to  that  marked  n  for  the  convenience  of  the  diggers. — Murchison. 

It  was  from  the  infillings  of  one  of  the  gravelly  depressions  between  these  elevations, 
south  of  Miask,  that  the  largest  lump  of  solid  gold  was  found,  of  which  at  that  time  (1824) 
there  was  any  record.  This  "  pepita"  weighs  ninety-six  pounds  troy,  and  is  still  exhibited 
in  the  museum  of  the  Imperial  School  of  Mines  at  St.  Petersburg. 


Report  of  the  production  of  Gold  aince  its  discover)/  in  California. 


1848 
1849 
1850 
1851 
1852 


£11,700 

18S3 

1,600,000 

1854 

5,000,000 

1855 

8,250,000 

1856 

1,700,000 

1857 

£12,500,000 
14,100,000 
13,400,000 
14,000,000 
13,110,000 


Exports  of  (jold  and  silver  bullion  from  the  United  States,  fts  shown  by  the  annual  offi- 
cial reports  on  '"'  Commerce  and  Navigation,"  by  the  Secretary  of  the  Treasury  of  the  United 
States.  (Prior  to  1855,  the  reports  do  not  show  separately  the  coin  from  the  bullio7i,  and 
in  the  following  years  silver  is  not  separated  from  fjold,  but  almost  the  entire  amount  was 
undoubtedly  goid.) 


1855 
1856 
1857 


$34,114,995 
28,689,946,  of  which  from  San  Francisco,  $6,947,404 
31,300,980  "  "  "  9,922,257 


The  gold,  the  production  of  foreign  countries,  imported  into  the  United  States  for  the 
years  ending  30th  June,  was  as  follows  : 

Te.ir.  Bullion.  Coin. 

1852  -  -  -  $608,257  -  -  -  $3,049,802 

1853  -  -  -  463,044  -  -  -  1,962,312 

1854  -  -  -  1,720,711  -  -  -  1,311,253 

1855  -  -  -  404,217  -  -  -  688,585 

1856  -  -  -  114,289  -  -  -  876,046 

1857  -  -  -  151,585  -  -  -  6,503,051 

Shipments  of  gold  from  San  Francisco  colony,  to  eastern  domestic  parts  and  foreign 
ports,  from  the  San  Francisco  Price  Current : 


1853 
1854 


United  St.ntos. 

§47,916,447titV 
46,289,649^ 


England. 

$4,975,662T-7fV 
3,781,080i%*o 


Other  Countries. 

$1,913,990  73 

1,163,779  78 


Total  in  1853 
«'        1854 


$54,906,100-nj^ 
51,234,508^ 


The  history  of  the  production  of  gold  in  California  and  the  States  of  the  Union,  is  well 
told  in  the  following  table,  showing  the  deposits  of  gold  in  the  limits  of  the  United  States. 
These  have  been  supplied  for  this  work  by  the  obliging  kindness  of  Mr.  Rockwell,  of  Wash- 
insrtoiL 


GOLD. 


573 


K) 


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574 


GOLD. 

2.  Branch  Mint,  San  Francisco. 


Period. 

California. 

Total 

1854 

1855 

1856 

1857  to  June  30- 

Total 

Dollars. 
10,842,281-23 
20,860,427-20 
29,209,218-24 
12,526,826-93 

Dollars. 
10,842,281-23 
20,860,427-20 
29,209,218-24 
12,526,826-93 

73,438,763-60 

73,438,763-60 

3.  Branch  Mint,  New  Orleans. 


Period. 

North 
Carolina. 

South 
Carolina. 

Georgia. 

Alabama,    j      California. 

Tennessee. 

O"""             ToUl. 
Sources.             *"«"• 

1838-17 

184S 

1849 

1850 

1S51 

1852 

18.53 

1854 

1855 

1S.56 

1857  to   ) 

June  30  j" 

Dollars. 
741 

Dollars. 

14,306 

1,488 

Dollars. 
37.364 
2,317 

Dollars.        Dollars. 
61.903 

6,717              1,124 
4,062           669,921 
3,560        4.575.576 
1,040     1  8,769.682 
3,777,784 
2,006,673 

-  ;     981.511 

411,517-24 

-  1      283,;}44-91 

-  '     129,328-39 

Dollars. 
1,772 
947 

Dollars. 
3,613 

2.783 
894 

Dollars. 

119,699 
12,593 

677,189 
4,580,030 
8,770,722 
8.777,784 
2,006,673 

981.511 

411.517-24 

283,344-91 

129,328-89 

Total     - 

741 

16,217 

39,681 

77,282      21,606,461-541       2,719 

7,290 

21,750,391-54 

4. 

Branch  Mint,  Charlotte,  North  Carolina. 

Period. 

North  Carolina. 

South  Carolina. 

California. 

Total 

Dollars. 

Dollars. 

Dollars. 

Dollars. 

1838  to  1847      - 

1,529,777 

143,941 

- 

1,673,718 

1848 

359,075 

11,710 

. 

370,785 

1849 

378,223 

12,509 

. 

390,732 

1850 

307,289 

13,000 

- 

320,289 

1851 

275,472 

25,478 

15,111 

316,061 

1852 

337,604 

64,934 

28,362 

430,900 

1853 

2-27,847 

61,845 

15,465 

305,157 

1854 

188,277 

19,001 

6,328 

213,606 

1855 

196,894-03 

14,27717 

5,817-66 

216,988-86 

1856 

157,355-18 

- 

15,237-35 

173,592-53 

1857  to  June  30 

75,696-47 

- 

- 

75,376-47 

Total 

4,033,189-68 

366,695-17 

87,321-01 

4,487,205-86 

5. 

Branch  Mint,  Dahlonega,  Georgia. 

Period. 

North 
Carolina. 

South 
Carolina. 

Georgia. 

Tennessee. 

Alabama. 

California. 

«"""     1           Total. 
Sources,   j 

Dollars. 

Dollars. 

Dollars. 

Dollars. 

Dollars. 

Dollars. 

Dollars. 

Dollars. 

1838^7 

64,a51 

95.427 

2,978.353 

32,175 

47.711 

. 

- 

3,218,017 

1848 

5,434 

8,151 

251,376 

2,717 

4,075 

- 

- 

271.753 

1849 

4,882 

7.323 

225,824 

2,441 

3,661 

. 

• 

244,131 

1^0 

4,.500 

5,700 

204.473 

1,200 

1,800 

80.025 

• 

247,693 

18.51 

1,971 

3,236 

154,723 

2,251 

2,105 

214,072 

951 

379,309 

18.52 

443 

57,543 

93,122 

750 

- 

824.931 

- 

476,789 

18.53 

2,085 

33,950 

56,984 

149 

. 

359,122 

. 

452,290 

18.54 

5,818 

15,983 

47,027 

223 

- 

211,169 

. 

280,225 

1855 

8,145-82 

9.113-27 

66,686-36 

. 

277-92 

47,428-70 

. 

116,652-07 

18.56 

- 

25,723-75 

44,107-99 

106-42 

- 

81,46710 

- 

101,405-26 

1857  to    1 
June  30  f 

- 

8,083-89 

25,097-63 

- 

- 

6,498-02 

- 

39,679-54 

Total     - 

92,629-82 

270,238-91 

4,137,773-98'  42,01242 

i 

59,629-92 

1,2-24,712S2  I      951 

5,827,948-87 

GOLD. 


575 


6.  Assay  Office,  New  York. 


Period. 

Virginia. 

North 
Carolina 

South 
Carolina. 

Georgia.       Alabama. 

Ten- 
nessee. 

California. 

Other 
Sources. 

Total. 

1854 
1855 
1S56 
1857  to 
June  SO 

Dollars. 

167 

2,370 

1,928 

[  1,531 

Dollars. 
3,916 
8,750 

805  07 

1,639 

Dollars. 

395 
7,620 
4,052  29 

2,663 

Dollars. 
1,242 
13,100 
41,101  23 

10,451 

Dollars. 

350 
233  62 

1,545 

Dollars 

Dollars. 
9,221,457 
25,025,896  11 
16,529,008  90 

9,899,957 

Dollars. 
1,600 

Dollars. 

9,227,177 

25,054,686  11 

16,582,129  16 

9,917,836 

Total 

10,996 

10,160  07 

14,730  29 

65,894  28  i  2,128  62 

60,676,319  01 

1,600 

60,781,828  27 

Summary  exhibit  of  the  entire  Deposits  of  Domestic  Gold  at  the   United  States  Hint  and 
Branches  from  1804  to  the  ZOth  June  1857. 


Mints. 


Philadelphia.    San  Francisco.    Nevr  Orleans 


Dollars. 

Virginia  -    - 

1,479,785  50 

N"th  Carolina 

4,400,373 

S'th  Carolina 

535,492 

Georgia   -    - 

2,374,793  50 

Tennessee    - 

85,563 

Alabama  -    - 

54,944 

New  Mexico 

48.397 

C.tlifornia     - 

226,839,521  62 

Other  Sources 

95,740 

Dollars. 


Total    -    -  235,864,614  62 


Dollars. 


741 

16,217 

3,963 

2,719 

77,232 


Dollars. 


4,033,189  6S 
366,695  17 


73,433,763  60  21,606,461  54 
-       1         7,290      I 


87,321  01 


Assay  Offic 


Dollars. 


Dollars. 

1,490,781  50 

8,537,093  67 

1,203,373  37 

6,618,142  76 

80,299  42 

193,934  54 

43,-397 

1,224,712  82  60,676,319  01  333,873,099  60 
951      I         1,600      I       105,581 


92,629  82 

270,238  91 

4,137,773  93 

42,012  42 

60,629  92 


Dollars. 
10,996      I 
10,160  071 
14,730  29 
65,894  28 

2,123  62 


r3,438,763  60  21,750,391  54  4,487,205  86  5,827,948  87  60,781,828  27i402,160,752  76 


Australian  Gold  Mines. — The  discovery  of  the  great  gold  field  in  Australia  to  the  west- 
ward of  Bathurst,  about  150  miles  from  Sydney,  was  officially  made  known  in  Great  Britain, 
by  a  despatch  from  Sir  C.  A.  Fitzroy  to  Earl  Grey,  on  the  18th  September,  1851,  many  per- 
sons with  a  tin  dish  having  obtained  from  one  to  two  ounces  per  day.  On  the  25th  of  May, 
he  writes  that  lumps  have  been  obtained  varying  in  weight  from  one  ounce  to  four  pounds. 
On  the  29th  of  May,  he  writes  that  gold  has  been  found  in  abundance,  that  people  of  every 
class  are  proceeding  to  the  locality,  that  the  field  is  rich,  and  from  the  geological  formation 
of  the  country,  of  immense  area.  By  assay  the  gold  is  found  to  consist  of  91"  1  of  that 
metal,  and  about  8-333  of  silver,  with  a  little  base  metal ;  or  of  22  carats  in  fineness.  July 
17th,  a  mass  of  gold  weighing  106  pounds  was  found  imbedded  in  the  quartz  matrix,  about 
53  miles  from  Bathurst ;  and  much  more,  justifying  the  anticipations  formed  of  the  vast 
richne.ss  and  extent  of  the  gold  field  in  this  colony.  This  magnificent  treasure,  the  prop- 
erty of  Dr.  Kerr,  surpassed  the  largest  mass  found  in  California,  which  was  28  pounds,  and 
that  in  Russia,  which  was  70  pounds,  now  in  the  museum  at  St.  Petersburg.  One  party  of 
six  persons  got  at  the  same  time  £4:00  in  ten  days  by  means  of  a  quicksilver  machine ;  and 
a  party  of  three,  who  were  unsuccessful  for  seven  days,  obtained  in  five  days  more  than  200 
ounces.  A  royalty  of  10  per  cent,  was  ordered  to  be  paid  on  gold  in  matrix  if  found  in 
Crown  lands,  and  5  per  cent,  if  found  in  private  property. 

Numerous  claims  have  been  made  by  persons  who  have  thought  that  they  had  given  the 
first  indications  of  gold  in  Australia.  To  Sir  Roderick  Murchison  is,  however,  due  the 
merit  of  pointing  out  that  gold  might  probably  be  found  in  Australia,  long  before  it  was 
known  in  Europe  that  gold  existed  in  that  important  colony.  Sir  Roderick  Murchison  thus 
gives  us  the  facts  :  "  Having  in  the  year  1844  recently  returned  from  the  auriferous  Ural 
Mountains,  I  had  the  advantage  of  examining  the  numerous  specimens  collected  by  my 
friend  Count  Strzelecki  along  the  eastern  chain  of  Australia.  Seeing  the  great  similarity  of 
the  rocks  of  those  two  distant  countries,  I  could  have  little  difficulty  in  drawing  a  parallel 
between  them ;  in  doing  which  I  was  naturally  struck  by  the  circumstance  that  no  gold  had 
yet  been  found  in  the  Australian  range,  which  I  termed  in  anticipation  the  '  Cordillera,'  im- 
pressed with  the  conviction  that  gold  would  sooner  or  later  be  found  in  the  great  British 
Colony.  I  learnt  in  1546  with  satisfaction  that  a  specimen  of  the  ore  had  been  discovered. 
I  thereupon  encouraged  the  unemployed  miners  of  Cornwall  to  emigrate,  and  dig  for  gold 
.as  they  dug  for  tin  in  the  gravel  of  their  own  district.  These  notices  were,  as  fiir  as  I 
know,  the  first  printed  documents  relating  to  Australian  gold." 

August  25th,  1851,  Lieutenant-Governor  C.  J.  Latrobe  announced  to  Earl  Grey  from 
Melbourne,  the  discovery  of  large  deposits  of  gold  in  that  district  of  the  colony.  In  a  sec- 
ond Parliamentary  blue  book,  issued  February  3,  1852,  it  is  stated  that  79,340  ounces  of 
gold,  worth  £257,855  7s.,  had  been  previously  forwarded  to  England ;  and  that  the  gold 


676 


GOLD. 


fields  of  the  colony  of  Yictoria  rival,  if  they  do  not  exceed  in  value,  the  first  discovered 
gold  fields  of  New  South  Wales ;  the  total  value  being  then  £300,000 ;  and  but  a  little 
time  afterwards  about  half  a  million  sterling.  Mr.  E.  Hargraves,  commissioner  for  Crown 
lands,  announced  from  Bathurst,  that  no  part  of  California  which  he  had  seen  has  produced 
gold  so  generally  and  to  such  an  extent  as  Summerhill  Creek,  the  Turon  River  and  its  trib- 
utaries. 

For  the  purpose  of  conveying  a  correct  idea  of  the  conditions  under  which  the  greatest 
quantity  of  the  Australian  gold  occurs,  three  plans  have  been  selected  from  different  dis- 
tricts.    The  first  of  these  {fig,  313)  represents  a  longitudinal  section  along  the  course  of  the 

313 


1.  Auriferous  drift. 

2.  Boundary  of  workings. 


3.  Boundary  fence. 

4.  Creswick's  Creek. 


west  quartz  vein  in  the  Clunes  gold-mining  field.  We  have  here,  as  indicated  by  the  darker 
portions  of  the  wood-cut,  the  quartz  vein  shown  in  section,  with  the  shafts  sunk,  and  the 
levels  driven  upon  it.  The  lighter  portions  of  the  figure  resting  on  the  quartzose  rock  is  an 
auriferous  drift ;  and  on  the  left  of  the  section  the  great  basaltic  formation  is  shown. 


314 


°„     I'    P     1 


5      ';        3         4 


cz~ 

^      OASALT      rc 


91A11 


1.  The  town  of  Ballarat  East 

2.  The  main  road. 

3.  The  Red  Streak-lead. 

4.  The  Creek. 

5.  Old  Post-office  Hill,  with  quartz  reef. 

6.  Basalt  escarpment  south  of  Golden  Point. 

7.  White  flat  recent  auriferous  alluvial  deposit. 

8.  Tarrowee  Creek. 

10.  The  Gravel-Pits  lead. 


Mi 


'.I  aii.l  li  i.ic  trtu  ^.liaft?  ^uIlk  into  the  ancient 

auriferous  alluvial  deposit. 
12.  Quartz  reef  beyond   the   town    of    Ballarat 

West,  shown  in  the  drawing. 
B  is  the  remains  of  a  lava  stream,  interrnjited  by 

the  schist  and  clay  slate  hills. 
D  D  is  the  gravel  strata  which  invariably  rests  on 

the  side  of  the  schist  hills  which  surround  the 

Ballarat  basin. 


Fig.  314  is  a  section  of  a  portion  of  the  Ballarat  gold  field.  It  is  an  east  and  west  sec- 
tion from  the  Red  Streak-lead  across  Post-office  Hill,  White  Flat,  the  township  of  Ballarat 
West,  and  the  quartz  reef  west  of  the  township  ;  and  it  shows  the  auriferous  drift,  schist, 
quartz,  and  basalt  fornrations  of  the  district. 

In  those  two  sections,  we  have,  therefore,  all  the  conditions  shown  of  the  processes  of 
mining  on  the  quartz  lodes  and  in  the  alluvial  deposits. 

Fig.  315  is  a  section  from  the  Eoroondara  and  Bulleen  gold  mines,  a  few  miles  from  the 
capital  of  Victoria.  It  is  the  east  and  west  section  of  the  Carlton  Estate  quartz  reef,  and  is 
mainly  given  to  illustrate  the  unskilful  and  dangerous  condition  of  many  of  the  workings 
undertaken  by  men  who  have  no  experience  in  subterranean  operations.  The  shaft,  if  such 
it  can  be  called,  is  about  40  feet  deep  ;  and  the  reef  dips  with  the  solid  strata  at  an  angle 
of  about  60  degrees  to  the  horizon. 

The  wall  of  the  shaft  at  a  is  not  supported  on  the  footwall  by  props  and  proper  timbering, 


GOLD. 


577 


which  it  should  be,  as  indicated  by  e  e  e. 
both  exceedingly  insecure.  This  is 
the  mode  of  proceeding  in  a  very 
important  working,  where  almost 
every  piece  of  quartz  broken  out 
contains  gold,  and  also  antimony  and 
iron.  At  the  point  f  the  quartz  reef 
was  exceedingly  rich,  and  there  it 
branches  off  into  small  strings,  yield- 
ing 22  ounces  of  gold  to  the  ton. 

It  is  not  necessary  here  to  trace 
the  progress  of  gold-mining  in  this 
colony.  The  quantity  of  gold  dis- 
covered and  exported  has  been 
enormous.  Some  exceedingly  large 
"  nuggets  "  have  been  found  ;  one 
in  Forest  Creek,  weighing  27  lbs.  6 
oz.  15  dwts.  and  the  Welcome  Nug- 
get, weighing  2,217  oz.  16  dwts. 

The  produce  of  the  gold  fields  of 
Victoria  in  1856  was  as  follows  : — 


The  quantities  brought  to  Melbourne  and  Geelong  by  escort, 
From  Castlemain  and  out-stations 

"  Sandhurst  and  do.  .... 
"  Maryborough  and  do.  .... 
"     Ballarat  and  do.        .... 

"     Beechworth  and     do.        .        -        .        - 


Brought  by  private  hand 

Quantity  which  has  evaded  duty 

In  the  treasury  banks  at  camp,  &c.,  and  in  transitu 

Total 


The  windlass  at  c  and  the  framework  at  d  are 


Oz. 

-  872,897 

-  599,100 

-  327,709 

-  1,009,822 

-  334,709 

2,644,237 

-  824,322 

59,411 

-  419,190 

3,947,160  oz. 


The  exports  of  gold  from  Australia  since  1851  have  been  as  follows : — 

Value.  Value. 


1851 
1852 
1853 
1854 


-  £907,113 

-  9,735,903 
10,445,700 

-  9,028,759 


1855 
1856 
1857 


£11,513,230 
12,740,480 
11,764,299 


The  quantities  of  gold  exported  from  New  South  Wales  alone  in  the  same  periods  have 
been : — 


Quantities. 


Value. 


1851  - 

1852  - 

1853  - 

1854  - 

1855  - 

1856  - 

1857  to  31st  March 


ozs.    dwts.  grs. 

144,120  17  16 

818,751  18  17 

548,052  19  21 

237,910  13  23 

64,384  14  3 

42,463  17  1 

17,088  8  0 


£  s.  d. 

468,336  0  0 

2,660,946  0  0 

1,781,172  0  0 

773,209  0  0 

209,250  0  0 

138,006  0  0 

64,081  10  0 


1,872,773     9     9  6,095,000  10     0 


The  remainder  being  the  produce  of  the  gold  fields  of  Victoria. 

Gold  has  been  discovered  in  some  considerable  quantities  in  Tasmania.  It  has  been 
reported  as  having  been  found,  although  as  yet  not  to  any  great  extent,  in  New  Zealand  ; 
and  it  is  well  known  that  this  precious  metal  is  found  in  all  the  islands  of  the  eastern  Arch- 
ipelago. 

The  rtccnt  discoveries  of  Gold  in  British  Columbia. — The  following  communication 
from  a  corresponden  tto  the  Victoria  Gazette,  Vancouver's  Island,  is  especially  interesting. 
It  is  dated  Upper  Fraser  River,  Nov.  28,  1858. 

Magnitude  of  the  Gold  Fields  of  British  Columbia. — "  That  the  auriferous  deposits  of 
Vol.  III.— 37 


578  GOLD. 

this  region  are  spread  over  a  considerable  scope  of  country  is  apparent  from  the  fact  that 
paying  diggings  have  already  been  found  on  the  Fraser  River,  extending  from  Fort  Hope 
almost  to  Fort  Alexander,  a  continuous  distance  of  nearly  400  miles.  Among  the  trib- 
utaries of  this  stream,  Thompson  and  Bridge  Rivers  are  known  to  be  auriferous — the  latter 
sufficiently  so  to  have  already  richly  rewarded  those  who  have  labored  upon  it  as  high  up  as  35 
or  40  miles  from  its  mouth,  while  the  former  has  been  ascertained  to  have  many  bars  that 
will  pay  in  its  bed.  On  two  of  its  confluents — Nicholas  and  Bonaparte  Rivers — good  dig- 
gings are  reported  to  have  been  recently  discovered.  How  many  more  of  the  numerous 
branches  of  these  streams  shall  yet  be  found  abounding  in  gold  remains  to  be  seen,  little  or 
no  prospecting  having  thus  far  been  done  upon  them.  Kor  is  tlie  extent  of  this  gold  field 
likely  to  be  limited  to  these  rivers  and  their  sources.  Coarse  gold  was  found  about  six 
weeks  since  by  some  packers  while  exploring  for  a  mule  route  around  Lake  Seton.  It  was 
discovered  on  a  large  creek  flowing  into  the  outlet  of  the  lake  at  a  point  about  15  miles 
from  the  Fraser.  The  dust  was  apparently  of  high  standard  value,  at  two  places  on  the 
Lillooet  River  bars  having  been  found  that  will  warrant  working  with  a  sluice.  The  first  of 
these  is  on  the  east  side  of  the  stream,  10  miles  above  Port  Douglas,  where  a  party  are  now 
washing  with  sluices  with  very  satisfactory  results.  When  I  passed  the  spot  they  had  been 
at  work  but  two  days  ;  the  first  day  three  men  took  out  $14  50c.,  the  next  day,  §18.  They 
showed  me  the  gold,  which  was  fine,  like  that  found  on  the  Lower  Fraser.  The  other  bar  is 
20  miles  above  Port  Douglas.  It  is  very  extensive,  and  promises  to  pay  as  well  as  the  one 
first  named,  though  it  has  not  yet  been  worked.  Bars  similar  to  these  are  abundant  on  the 
Lillooet,  and  the  fact  of  these  having  been  prospected  was  owing  to  the  accident  of  a  log 
cabin  having  been  built  near  them,  and  not  because  they  seemed  more  likely  to  contain 
gold  tlian  the  others.  For  100  miles  above  the  Pavilion,  and  beyond  what  is  termed  the 
Canoe  Country,  the  banks  of  Fraser  River  have  been  proved  to  pay  even  better  than  below, 
the  gold  being  coarser  and  more  easily  saved,  as  well  as  more  plentiful.  It  will  thus  be 
seen  that  the  gold  fields  of  British  Columbia,  ascertained  to  be  paying,  to  say  nothing  of 
rumored  discoveries  beyond,  are  tolerably  extensive.  They  do  not,  it  is  true,  rival  those 
of  California  or  Australia  in  magnitude  ;  but  that  they  cover  a  large  scope  of  country,  and 
will  give  employment  to  a  large  population,  is  settled  beyond  controversy  or  question." 

Richness  of  the  Mines. — "  To  claim  that  the  Fraser  River  mines  are  as  rich,  or  that 
labor  has  been  generally  as  well  rewarded  in  them  as  in  the  mines  of  California  at  an  early 
day,  would  be  idle.  I  might  say  much  in  explanation  of  the  numerous  failures  that  attended 
the  first  adventurers  to  these  mines,  without  making  myself  their  apologist — how  the 
miners  came  too  soon  and  in  too  great  numbers — how  the  river  kept  up,  and  of  the  many 
disadvantages  under  which  they  laJDored  ;  all  might  be  enlarged  upon  were  it  not  now  well 
known  to  the  public.  In  regard  to  this  section,  however,  I  may  say  those  pioneers  who 
worked  here  last  winter  and  spring  uniformly  made  large  wages  ;  and  that  those  who  came 
in  since  have  been  able  to  remain,  paying  the  enormous  prices  they  have  done  for  pro- 
visions, proves  that  tliey  must  have  had  good  paying  claims  most  of  the  time.  The  cost  of 
living  here,  with  other  necessary  expenditures,  could  not  have  been  less  than  $4  a  day  to 
the  man,  vet  I  find  all  have  been  able  to  defray  their  current  expenses,  while  many  have 
accumulated  large  sums — sufficiently  large  in  a  majority  of  cases,  with  those  who  have  been 
here  any  length  of  time,  to  lay  in  a  winter's  stock  of  provisions,  even  at  the  present  high 
prices.  That  better  average  wages  can  be  made  here  than  in  any  part  of  California  at  pres- 
ent there  is  no  doubt.  This  can  be  done  even  with  the  present  want  of  ditches  and  indif- 
ferent appliances  for  taking  out  the  gold.  These  diggings,  owing  to  the  fineness  of  the  dsst 
and  the  difficulty  of  saving  it,  require  to  be  worked  with  sluices — a  mode  that  has  been 
introduced  to  but  a  limited  extent  as  yet,  owing  to  the  want  of  lumber  as  well  as  of  wheels 
or  ditches  for  supplying  water.  When  sluices  shall  have  been  generally  brought  into  use, 
more  than  twice  the  amount  now  realized  can  be  taken  out  to  hand.  Anotlier  cause  that 
will  tend  to  render  these  mines  highly  remunerative  in  the  aggregate  is,  that  every  man  will 
be  able  to  secure  a  claim,  and  that"^but  little  capital  will  be  required  for  starting  opera- 
tions ;  hence  evei^  one  will  enjoy  the  full  fruits  of  his  own  labor,  and  none  need  remain 
idle.  For  this  winter,  owing  to  the  lateness  with  which  provisions  have  been  got  in,  not 
much  will  be  done  ;  no  one  here  expects  it ;  the  utmost  that  will  be  aimed  at,  as  a  general 
thing,  will  be  to  make  enough  to  pay  expenses  of  living,  to  prospect  a  little,  and  be  on  hand 
at  the  breaking  up  of  winter.  With  the  coming  of  spring  large  operations  will  be  entered 
into,  and  all  here  entertain  the  most  sanguine  anticipations,  or  rather,  I  should  say,  fullest 
confidence  as  to  the  results." 

Tfieir  durability. — "  That  these  mines  will  be  found  not  only  rich  and  extensive,  but 
also  lasting,  I  am  fully  satisfied.  Apart  from  their  vast  extent  of  surface,  the  diggings,  at 
one  time  thought  to  be  shallow,  are  now  known  to  run  downward  in  n>any  localities  to  a 
good  depth.  It  has  lately  been  ascertained  that  not  only  the  bars  along  the  river,  but  many 
of  the  lower  benches  or  table  lands,  contain  sufficient  gold  to  pay  where  water  can  be 
brought  upon  them,  which  in  most  cases  can  easily  be  done.  These  benches  are  not  only 
numerous,  but  often  of  great  extent,  and  would  afford  employment  for  a  large  number  of 


GRINDING  AND  CRUSHING  MACHINERY.  579 

men  for  many  years  to  come.  Little  or  no  search  has  been  made  as  yet  for  drift  diggings 
or  quartz,  though  there  are  abundant  indications  that  both,  of  a  paying  ciiaracter,  exist. 
Fine  ledges  of  quartz,  in  fact,  present  themselves  almost  everywhere,  though  no  thorough 
examination  has  been  made  of  their  quality.  The  banks  of  Bridge  River  consist  of  alternate 
strata  of  slate  and  quartz  rock,  the  most  favorable  possible  geological  formation  for  gold.  I 
would  venture,  then,  after  having  seen  considerable  of  the  mines  in  this  quarter,  to  express 
the  confident  opinion  that  they  will  prove  sufficiently  extensive,  productive,  and  lasting,  to 
warrant  a  lar"-e  immigration  to  this  country  in  the  ensuing  season,  and  that  British  Colum- 
bia is  destined  to  become  another  great  gold-producing  region,  ranking  next  to  California 
and  Australia  in  the  amount  slie  will  hereafter  annually  yield  of  this  precious  commodity." 

Such  is  a  general  view  of  the  gold-producing  districts  of  the  world.  Much  fear  has  been 
expressed  lest  the  influx  of  gold  saould  reduce  the  value  of  that  metal.  Since  the  discov- 
ery of  the  Californian  gold  field  in  1848,  not  less  than  £159,807,18-1  sterling  has  been  added 
to  the  wealth  of  Europe  and  America  from  the  great  gold  fields  of  California  and  Australia. 
Tills  question  cannot  be  discussed  in  this  place,  but  it  is  one  of  the  greatest  interest,  de- 
manding alike  the  consideration  of  the  politician  and  the  social  philosopher. 

GOLD  THREAD,  or  spii<i  goUl,  is  a  flatted  silver-gilt  wire,  wrapped  or  laid  over  a 
thread  of  yellow  silk,  by  twisting  with  a  wheel  or  iron  bobbins.  By  the  aid  of  a  mechanism 
like  the  braiding  machine,  a  number  of  threads  may  thus  be  twisted  at  once  by  one  master 
wheel.  The  principal  nicety  consists  in  so  regulating  the  movements  that  the  successive 
volutions  of  the  flatted  wire  on  each  thread  may  just  touch  one  another,  and  form  a  contin- 
uous covering.  The  French  silver  for  gilding  is  .said  to  be  alloyed  with  5  or  6  penny- 
weights, and  ours  with  12  pennyweights  of  copper  in  the  pound  troy.  The  gold  is  applied 
in  leaves  of  greater  or  less  thickness,  according  to  the  quality  of  the  gilt  wire.  The  smallest 
proportion  formerly  allowed  in  this  country  by  act  of  parliament  was  100  grains  of  gold  to 
one  pound,  or  5,760  grains  of  silver ;  but  more  or  less  may  now  be  used.  The  silver  rod 
is  incased  in  the  gold  leaf,  and  the  compound  cylinder  is  then  drawn  into  round  wire  down 
to  a  certain  size,  which  is  afterwards  flatted  in  a  rolling-mill. 

The  liquor  employed  by  goldsmiths  to  bring  out  a  rich  color  on  the  surface  of  their  trin- 
kets, is  made  by  dissolving  1  part  of  sea-salt,  1  part  of  alum,  2  parts  of  nitre,  in  3  or  4  of 
water.  The  pickle  or  sauce,  as  it  is  called,  takes  up  not  only  the  copper  alloy,  but  a  notable 
quantity  of  gold ;  the  total  amount  of  which  in  the  Austrian  empire  has  been  estimated 
annually  at  47,000  francs.  To  recover  this  gold,  the  liquor  is  diluted  with  at  least  twice  its 
bulk  of  boiling  water,  and  a  solution  of  very  pure  green  sulphate  of  iron  is  poured  into  it. 
The  precipitate  of  gold  is  washed  upon  a  filter,  dried,  and  purified  by  melting  in  a  crucible 
along  with  a  mixture  of  equal  parts  of  nitre  and  borax. 

GRLVDING  AXD  CRUSHLVG  MACHLVERY.  Crushing-Mill.  This  machine  was 
introduced  into  the  mines  of  Cornwall  and  Devon  in  the  early  part  of  the  present  century. 
In  its  simplest  form  it  consists  of  two  rollers  mounted  in  a  strong  iron  frame,  and  kept  in 
contact  by  means  of  screws  ;  motion  is  communicated  to  one  of  the  rolls,  either  by  a  water- 
wheel  or  steam-engine,  but  the  other  is  made  to  revolve  by  the  friction  generated  between 
the  moving  roll  and  the  stuff  to  be  crushed.  This  mill  is  usually  employed  for  reducing 
mineral  substances  wliich  have  already  received  some  mechanical  preparation,  but  machines 
have  been  contrived  with  a  series  of  rolls,  set  below  each  other,  into  which  the  stuff  is 
introduced  as  brought  from  the  lode  under  ground.  In  order  to  effect  this  operation,  the 
upper  rolls  are  fluted,  and  the  lower  ones  have  various  speeds  and  diameters,  but  it  may  be 
remarked  that  although  this  arrangement  has  been  somewhat  extensively  employed  in  the 
north  of  England,  yet  it  has  found  few  advocates  either  in  Wales  or  Cornwall. 

The  practice  of  keeping  the  rolls  together  by  screws  acting  on  the  bearings  is  objection- 
able, since  the  entrance  of  a  piece  of  steel,  or  other  hard  substance,  of  greater  width  than 
the  fixed  opening  between  the  rolls,  immediately  produces  a  stoppage,  and  strains  the  appa- 
ratus or  otherwise  causes  serious  breakages  to  some  of  the  parts.  In  order  to  obviate  these 
evils,  the  rolls  are  usually  adjusted  and  kept  in  position  by  weighted  levers  pressing  on 
their  axes. 

As  the  machines  employed  in  Cornwall  may  be  considered  the  most  effective  in  opera- 
tion as  well  as  complete  in  their  construction,  that  type  is  selected  for  representation. 

B  B  {fig.  316)  are  the  crushing-rollers  fitted  in  a  strong  frame-work  of  cast  iron,  which 
is  stayed  by  a  wrought-iron  bar  6,  and  firmly  bolted  to  longitudinal  beams  inserted  in  the 
walls  of  the  crushing-house.  The  rollers  revolve  in  bearings,  which  arc  so  arranged  as  to 
slide  in  grooves,  and  therefore  admit  of  the  cylinders  being  brought  nearer  to  or  separated 
farther  from  each  other.  To  keep  the  rollers  in  contact  and  yet  allow  the  action  to  take 
place,  a  weighted  lever  a  is  placed  on  each  side,  which  by  moans  of  tension  bars  connected 
with  one  of  the  bearings,  keeps  a  constant  pressure  upon  the  rollers.  The  ore  to  be  crushed 
is  lodged  upon  a  floor  c,  and  introduced  into  a  hopper  n,  from  which  it  falls  lietwoen  the 
rolls  ;  the  requisite  crushing  pressure  being  attained  by  increasing  or  decreasing  the  weights 
applied  to  the  end  of  the  lever.  The  crushed  ore  pa.sses  from  between  the  rollers  b  n  into 
the  higher  extremity  of  an  inclined  cylinder  e,  made  of  coarse  gauze,  or  perforated  plate, 


580 


GRINDING  AND  CRUSHING  MACHINERY. 


which  being  set  in  motion  by  the  same  power  as  the  rollers  themselves,  separates  the  pul- 
verized material  into  two  classes.  That  portion  which  passes  through  the  sieve  falls  into  a 
wagon  placed  oa  the  floor  of  the  house,  whilst  the  other,  which  is  too  large  to  escape 

316 


through  the  openings,  is  carried  to  the  lower  end  of  the  cylinder,  from  whence  it  passes  into 
an  inverted  bucket-wheel  f,  by  which  it  is  again  conveyed  into  the  hopper  to  be  recrushed. 

The  modifications  to  the  foregoing  arrangement  may  be  thus  briefly  noticed  : — 

In  some  machines  the  feed-hopper  is  made  of  sufficient  capacity  to  hold  from  20  to  25 
cwt.  of  stuff,  which  is  introduced  by  means  of  a  tram  wagon,  and  renders  hand  feeding  un- 
necessary. The  shoot  conveying  the  crushed  ore  to  the  rotating  sieve  k,  is  sometimes 
divided  at  the  bottom  into  two  parts,  one  to  deliver  rough,  and  the  other  fine  stuff.  In  con- 
nection with  each  division  is  a  cylindrical  riddle  revolving  and  separating  the  work  accord- 
ing to  the  fineness  or  coarseness  of  the  mesh  employed. 

A  circular  sieve,  divided  midway  into  two  parts,  each  of  a  different  mesh,  is  in  some 
instances  advantageously  substituted  for  two  sets  of  sieves ;  wliilst,  in  other  cases,  circular 
sieves  are  omitted,  the  operation  of  sizing  being  performed  by  fixing  perforated  plates  on 
the  periphery  of  the  inverted  wheel. 

Instead  of  one  roll  being  drawn  towards  the  other,  they  are  more  commonly  kept  in 
contact  by  direct  pressure,  which  is  effected  as  shown  infiffs.  317,  318. 

A,  lever  hung  to  the  cast-iron  frame  b  at  c,  and  pressing  upon  pin  at  r>.  When  it  is 
required  to  change  the  rollers,  the  pressure  resulting  from  the  lever  a  and  weighted  box  E, 
is  relieved  by  means  of  the  screw-tackle  f. 

The  considerations  which  should  be  attended  to  in  constructing  a  crushing-mill,  are, 
fii-st  to  make  all  the  parts  sufficiently  strong  to  meet  the  varying  resistance's  which  contin- 
ually occur  in  crushing.  For  this  purpose,  the  frame-work  to  receive  the  rolls  ought  to  be 
of  good  cast  iron,  the  axles  of  the  rollers  of  best  wrought  iron,  and  the  cylinders  of  the 
hardest  and  most  uniform  metal.     2dly.  To  design  the  machine  so  that  the  matter  to  be 


crushed  may  be  readily  delivered  into  the  hopper,  sized  by  the  circular  sieves  for  the  dress- 
ing process,  and  such  portions  as  are  not  properly  crushed,  returned  to  the  rolls  without  the 
int€rvention  of  manual  labor.     In  order  to  effect  this,  the  inverted,  or  raff  wheel  d,  /y.  318, 


GRINDING  AND  CRUSHING  MACHINERY. 


581 


shown  in  section,  ought  to  be  made  of  sufiBcient  diameter  to  allow  the  stuff,  on  being  dis- 
charged, to  descend  by  its  own  gravity  into  the  feed-hopper.  3dly.  To  extend  from  the 
axis  of  the  rollers,  long  tumbling  shafts,  a  i.,fig.  318,  and  fix  on  their  ends  the  driving 


318 


wheels  b  b,  allowing  a  little  play  in  the  plummer  blocks,  so  that  any  undue  opening  of  the 
rolls  may  not  vary  the  pitch  line  of  the  wheels  b  b,  to  such  an  extent  as  to  endanger  the 
safety  of  the  teeth.  4thly.  To  construct  the  roll  so  that  it  may  be  readily  changed,  yet 
maintained  on  its  axis  without  slipping  when  in  motion.  One  of  the  most  efficient  plans  for 
this  purpose,  is  shown  in  the  following  wood-cut,  in  which  a  is  the  axis  or  arbor,  and  d  the 
roil. 

319 


Ct^3C  ^Q 


It  will  be  seen  that  the  cylinder  roll  is  fitted  with  four  internal  projections ;  these  are 
of  the  same  length  as  the  portion  of  the  groove  marked  b  b',  but  no  wider  than  the  nar- 
rower part  of  the  groove  c.  When  the  cylinder  is  to  be  fixed  on  the  axis,  the  studs  are 
introduced  into  the  recesses  c,  and  the  cylinder  advanced  into  its  working  position,  when  it 
is  turned  until  the  studs  fit  into  that  portion  of  the  recess  between  b  b',  and  which  are  then 
wedged  to  the  roll  by  a  close-fitting  cutter. 

5thly.  Tlie  diameter  of  the  rolls  should  be  decreased,  and  the  length  inn'eased  in  pro- 
portion to  the  fineness  of  the  stuft"  to  be  crushed,  since  a  fine  material  requires  a  longer  line 
of  contact,  and  not  so  large  a  grip  as  coarser  substances. 

In  practice  it  has  been  found  advantageous  to  make  the  roller  placed  on  the  driving 
sliaft  somewhat  longer  than  that  which  is  opposite,  and  to  work  the  roils  by  spur  gearing 
rather  than  by  friction,  since  the  latter  is  proved  to  furnish  less  economical  results  than  the 
former.  It  has  also  been  found  injudicious  to  harden  the  rolls  by  chilling  ;  hence  ordinary 
sand-cast  rolls  are  most  frequently  employed. 

Tiie  speed  of  the  rolls  varies  from  45  to  60  feet  per  minute,  but  this  necessarily  differs 
with  the  character  of  the  stuff  to  be  crushed.  Again  great  variation  is  experienced  in  tiie 
quantities  crushed  witliin  a  given  period,  since  a  small  amount  of  moisture  in  vein  stuff  of  a 
certain  class  makes  it  cake,  and  will  thus  considerably  reduce  the  produce  of  the  mill.  On 
the  other  hand,  if  the  matter  operated  upon  be  very  dry,  heavy,  and  brittle,  as  in  the  case 


582 


GRINDING  AND  CRUSHING  MACHINERY. 


of  some  varieties  of  lead  ore,  the  produce  may  be  much  increased,  since  the  mill  can  be 
driven  at  a  great  speed  ;  a  less  bulk  will  have  to  pass  for  a  given  weight,  and  there  will  be 
a  smaller  quantity  of  material  carried  back  by  the  raff  wheel  to  be  recrushed. 

Variable  speeds  have  sometimes  been  tried  in  order  to  produce  friction  together  with 
pressure  at  the  line  of  contact,  but  it  has  been  found  that  any  departure  from  a  uniform 
speed  on  the  two  surfaces,  absorbs  a  considerable  additional  amount  of  power,  without  ma- 
terially augmenting  the  results. 

Arrastre  or  ta/iona. — This  machine  is  extensively  employed  in  the  mining  districts  of 
Mexico,  lor  grinding  silver  ores  previous  to  their  amalgamation. 

It  consists  of  a  strong  wooden  axle  a,  (Jiff.  320,)  moving  on  a  spindle  in  a  beam  b  above 


320 


i^^^ 


k 


5 


■^r^^3i~^^'^^7\Z 


it,  and  resting  on  an  iron  pivot  beneath,  turning  in  an  iron  bearing,  which  is  inserted  into  a 
post  of  wood  c,  which  rises  about  a  foot  above  the  ground  in  the  centre  of  the  arrastre. 
The  shaft  a  is  crossed  at  right  angles  by  two  strong  spars  n  d,  which  form  four  arms,  each 
about  5  feet  long,  one  excepted,  which  is  9  feet  long,  to  admit  of  two  mules  being  attached 
to  it;  by  this  arm  the  machine  is  worked.  The  grinding  is  performed  by  four  large  porphy- 
ritic  or  basaltic  stones,  two  of  which  are  shown,  e  e.  These  are  loosely  attached  by  thongs 
of  leather,  or  small-sized  rope,  to  the  four  arms,  and  are  dragged  round  over  the  ore,  which 
is  put  in  with  water,  until  it  is  ground  to  a  very  fine  slime  or  mud,  called  the  lama.  One 
of  these  machines,  wlien  in  good  working  condition,  will  grind  from  600  to  800  pounds 
weio'ht  of  ore  in  twenty-four  hours.  In  Guanaxuato,  where  the  best  and  finest  grinding  is 
obtained  in  the  arrastres,  the  lining  or  foundation  and  the  grinding  stones  arc,  of  course, 
grained  porpliyry.  and  form  a  rough  surface.  The  cost  of  this  apparatus  in  Mexico,  includ- 
ing the  paving  of  the  bottom,  and  the  four  vietapiles  or  stones,  is  on  an  average  £7.  The 
original  weight  of  a  mctapile  is  about  700  pounds,  its  dimensions  are  2  feet  8  inches  long, 
18  inches  broad,  and  18  inches  deep.  Notwithstanding  the  hardness  of  the  stones  em- 
ploved,  they  are  so  worn  as  to  become  unserviceable  in  the  course  of  ten  or  twelve  weeks ; 
the  bottom,  however,  is  only  rcjilueed  once  in  twelve  months. 

This  apparatus  is  well  suited  to  patio  amalgamation,  but  it  affords  bad  results  for  the 
power  expended. 

Edge  mill. — Tiiis  machine  is  employed  for  the  purpose  of  reducing  gold  and  silver  ores 
to  an  impalpable  powder.  It  is  also  used  extensively  in  grinding  Hints,  stones,  slags,  and  a 
varietv  of  other  products.  However  much  the  details  of  this  apparatus  may  vary,  its  prin- 
ciple is  the  same  in  all  cases.  Two  vertical  runners  rotate  on  the  outer  circumference  of  a 
flat  or  slightly  conical  basin,  and  afford  a  frictional  or  grinding  area  equal  to  the  difference 
of  distance  performed  bi)  the  innrr  and  outer  edges. 

The  subjoined  wood-cut,  /?(/.  321,  represents  a  mill  constructed  at  the  Mould  Foundry, 
Flintshire,  a,  rotating  pan,  resting  upon  frictional  wheels  b  ;  c.  vertical  shaft  firmly  keyed 
to  pan  A,  to  which  motion  is  communicated  by  wheel  gearing  n.  The  runners  e  e  revolve 
on  arm  F,  and  may  be  of  cast  iron  or  of  stone  bound  with  a  ring  of  iron.  These  runners 
have  no  progressive  motion,  but  have  free  play  to  rise  or  fall  on  axis  c,  and  in  the  stay 
slots  G  G. 


GRINDING  AND  CRUSHING  MACHINERY. 

321 


583 


The  following  dimensions  and  particulars  are  derived  from  one  of  the  edge  mills  recently 
working  at  tlie  Fabrica  La  Constante  in  the  province  of  Guadalajara,  Spain  : — 


6  feet. 

Centre  20  in.  edge  16  in. 

3  tons,  15  cwt. 
200  feet  per  minute. 

4  feet. 

10  holes  to  the  lineal  inch. 
60  "  " 

350  lbs. 
7. 


Diameter  of  edge  runner         .         .         .         - 

Width       of    do.     do.  .         .         .         - 

Weight     of    do.     do.  .... 

Speed  of  runner     -..--- 

Diameter  of  interior  circle  of  runner 

Gauge  of  stuff"  previous  to  its  being  ground    - 
Do.  after  it  leaves  the  mill     - 

Quantity  of  stuff"  reduced  per  10  hours  - 

Horse  power  employed  -  -  -  -  - 
In  some  machines  erected  at  the  Real-dcl-Monte  mines  in  Mexico  the  stones  were  6  feet 
in  diameter  and  12  inches  wide.  They  were  fitted  with  a  ring  of  wrought  iron  3  inches 
thick.  Each  pair  of  runners  revolved  round  a  centre  on  its  own  a.xis,  in  a  cast-iron  basin 
of  which  the  l)0ttom  was  7  inches  thick.  At  first  good  results  were  obtained:  each  mill,  if 
kept  constantly  at  work,  ground  nearly  ten  tons  per  week  ;  but  as  their  axles,  and  partic- 
ularly the  wrought-iron  rings  and  cast-iron  bottoms,  began  to  wear  hollow,  and  to  lose  an 
even  surface,  the  grinding  rapidly  diminished,  and  with  one  year's  work  they  were  com- 
pletely worn  out. 

The  chief  advantage  of  this  macliine  is  its  simplicity  of  construction  and  consequent 
small  first  cost ;  but  all  its  parts  require  to  be  made  of  great  strength,  and  therefore  of  pro- 
portionate weight ;  hence,  in  addition  to  the  rapid  wear  to  which  it  is  liable,  this  appanittis 
becomes  objectionable  for  countries  where  transit  of  heavy  machinery  is  more  than  ordi- 
narily difficult  and  expensive. 

Horizontal  inUl. — For  the  purpose  of  reducing  auriferous  and  argentiferous  ores  to  an 
exceedingly  fine  powder,  and  where  dry  grinding  is  essential,  no  apparatus  has  been  found 
more  eff'ectual  than  the  horizontal  mill.     It  affords  the  largest  area  of  frictional  surface  for 


584 


GRINDING  AND  CRUSHING  MACHINERY. 


the  least  wear  and  tear,  and  accomplishes  equal  results  at  a  cost  not  exceeding  one-fourth 
of  that  incident  to  the  edge  mill. 

The  construction  of  the  horizontal  mill  will  be  rendered  intelligible  by  the  aid  of  the 
following  illustration,  fg.  322,  in  which  one  pair  of  stones  is  shown  in  section,     a  is  a  cir- 


4. 


m. 


S       ' 


im: 


cular  hopper,  into  which  the  stuff  to  be  ground  is  introduced  ;  b  b,  small  pipes  of  sheet 
iron,  for  delivering  the  stuff  between  the  surfaces  of  the  runner  c  and  bed-stone  c' ;  d,  cas- 
ing enclosing  the  runner  into  which  tlie  ground  material  is  delivered  ;  e,  hole  in  centre  of 
runner ;  f,  driving  shaft,  with  continuation  shaft  g,  for  giving  motion  to  a  Jacob's  ladder 
if  requisite ;  ii  h',  regulating  screw  for  elevating  runner  c ;  j,  driving  wheel ;  k,  crown 
wheel ;  l,  wheel  giving  motion  to  pinions  m  m'  ;  and  k,  vertical  shaft,  to  drive  any  supple- 
mentary apparatus  which  may  be  requiring  such,  as  sizing  sieve,  &c.  Four  pairs  of  stones 
are  usually  driven  by  the  wheel  l.  The  surface  of  the  runner  is  in  contact  with  the  bed- 
stone, from  the  periphery  to  within  one-third  of  its  diameter.  The  line  of  the  runner  then 
feathers  upwards,  in  order  to  receive  the  stuff  freely,  and  to  equalize  the  resistance  through- 
out the  area  of  the  bed-stone. 

The  following  particulars  will  convey  much  practical  infonnation  rclntive  to  this  machine : 


Diameter  of  stones  .         .         .         - 

Thickness  of  bed-stone    -         -         -         - 

Ditto  runner  .... 
No.  of  revolutions  of  stone  per  mmute  - 
Gauge  of  stuff  in  stopper 

Ditto  on  delivery 

Quantity  of  stuff  ground  per  10  hours  - 
Power  employed  in  horses  ... 
Revolutions  of  sizing  sieve  ... 
Diameter  of  ditto    .... 

Length  of  ditto    - 

No.  of  holes  per  square  inch  in  sizing  sieve 


4  feet  2  inches. 

12  inches. 

14  inches. 

108. 

100  holes  to  the  square  inch. 

3,600  ditto 

1  ton  per  pair  of  stones. 

About  5  per  ditto. 

23  per  minute. 

30  Inches. 

108. 

3,600. 


GRINDING  AND  CRUSHING  MACHINERY 


585 


Character  of  runner Coarse  conglomerate. 

Ditto         bed  stone Compact  quartz,  moderately  hard. 

Duration  of  runner Average  18  weeks. 

Ditto       bed-stone Ditto    22  ditto. 

When  dressed Every  third  day. 

From  a  series  of  practical  experiments  made  on  the  same  stuff  by  these  several  mills 
the  following  results  have  been  obtained  : — 


No.  of  Holes  per 
square  inch  in 
Sizing  Sieve. 

Quantity  of 

Stutf  gi-oiind  in 

10  hours. 

Horse  Power. 

Cost  ptT  ton 

1.  Horizontal  mill 

2.  Crushing  mill  - 

3.  Edge  mill 

3,600 
3,600 
3,600 

Cwts. 
20 
13 
13 

5 
5 

7 

«     d. 
2      3 
1     7 
6   10 

J.  D. 

MackwortlCs  Patent  Crmhing  Rollers,  Jigs.  323  and  324,  for  Coal  and  other  Minerals. 
These  rollers  are  made  conical  to  equalize  the  wear,  and  as  one  roller  travels  faster  than  the 

323 


586 


GUANO. 


other,  the  fragments  are  partially  turned  over,  so  as  to  present  their  weakest  line  of  fracture 
to  the  direction  of  the  crushing"  force.  Less  power  is  required  to  work  these  rollers.  In 
lieu  of  the  counterbalance  weight  usually  employed  to  allow  the  rollers  to  separate  and  pass 
excessively  hard  fragments,  and  to  bring  the  rollers  together  again,  the  machine  is  made 
more  compact,  and  simplilied  by  connecting  2  brass  collars,  in  which  the  rollers  work  by  a 
number  of  bands  or  cords  of  vulcanized  india-rubber  strongly  stretched.  A  compound  cord 
of  india-rubber,  3  inches  in  diameter,  composed  of  144  small  and  separate  cords,  when 
stretched  to  double  its  natural  length,  gives  a  strain  of  3  tons.     The  brass  collars  do  not 

revolve. 

GUANO.  This  extraordinary  excremcntitious  deposit  of  certain  sea-fowls,  which  occurs 
in  immense  quantities  upon  some  parts  of  the  coasts  of  Peru,  Bolivia,  and  Africa,  has  lately 
become  an  object  of  great  conunereial  enterprise,  and  of  intense  interest  to  our  agricultural 
world.  More  than  twenty  years  ago  it  was  exhibited  and  talked  of  merely  as  a  natural 
curiosity,  but  since  that  time  the  quantity  imported  into  England  alone  has  risen  from 
30  000  to  300,0U0  tons,  (in  1855,)  the  value  of  which  was  estimated  at  no  less  than 
£3,000,000.  .     .^      ^ 

Natural  History  ami  Geography.— Euano,  in  the  language  of  Peru,  signifies  dung ;  a 
word  spelt  bv  the  Spaniards,  guano. 

The  conditions  essential  for  the  preservation  of  these  excrements  appear  to  be  the  exist- 
ence of  a  soil  consisting  of  a  mixture  of  sand  and  clay,  in  a  country  where  the  birds  are 
allowed  to  live  for  ages  undisturbed  by  man  or  man's  works,  and  where,  moreover,  the  cli- 
mate is  very  drv,  free  not  only  from  rain,  but  also  from  heavy  dews. 

These  conditions  appear  to  have  been  combined  to  a  remarkable  extent  on  the  coasts  ot 
Peru  and  Bolivia,  between  latitudes  13°  north,  and  21°  south  of  the  equator,  for  although 
beyond  this  region  the  flocks  of  cormorants,  flamingoes,  cranes,  and  other  sea-fowl,  appear 
to  "be  equally  numerous,  vet  the  excrement  is  rapidly  carried  away  by  the  ram  or  dew.  ■ 

It  is  then  the  dryness  of  the  climate  chieflv  which  has  permitted  the  guano  to  accumu- 
late on  these  coasts,  for,  savs  Mr.  Darwin  :  *  "  In  Peru,  real  deserts  occur  over  wide  tracts 
of  country.  It  has  becom'e  a  proverb  that  rain  never  falls  in  the  lower  part  of  Peru  " 
And  again  :  "  The  town  of  Iquique  contains  about  1,000  inhabitants,  and  stands  on  a  little 

825 


plain  of  sand  at  the  foot  of  a  great  wall  of  rock,  2,000  feet  in  height,  the  whole  utterly 
desert.  A  slight  shower  of  rain  falls  only  once  in  very  many  years."  Indeed  since  three- 
fifths  of  the  constituent  parts  of  guano  are  soluble  in  cold  water  Prof.  Johnstone  very  justly 

*  Besearclies  in  Geology  and  Katural  History,  p.  42S. 


GUANO. 


587 


observes  that,*  *'  A  single  day  of  English  rain  would  dissolve  out  and  carry  into  the  sea  a 
considerable  portion  of  one  of  the  largest  accumulations  ;  a  single  year  of  English  weather 
would  cause  many  of  them  entirely  to  disappear" 

Such  being  the  case,  we  might  expect  to  find  similar  accumulations  in  other  hot  and  dry 
climates,  as  in  Egypt,  and  in  Africa,  e.  g.,  in  the  neighborhood  of  the  great  desert ;  and 
only  a  few  years  since  a  considerable  deposit  of  guano  was  found  in  the  Kooria  Mooria 
Islands. 

The  export  of  guano  from  the  Cincha  Islands  has  increased  considerably  during  the  last 
few  years  :  between  300,000  and  400,000  tons  are  the  annual  amount  at  present,  which  is 
effected  by  the  aid  of  900  working  hands,  320  of  them  being  Chinese,  who  enter  into  con- 
tracts to  serve  their  employer  (the  Government  contractor)  Don  Domingo  Elias,  for  4  dol- 
lars a  mouth,  renewing  it,  if  they  choose,  with  the  increase  of  4  dollars  monthly,  and  a 
bonus  of  120.  Those  who  work  on  their  own  account  are  paid  8  and  10  rials,  4  and  5  shil- 
hngs,  for  each  cart  that  they  load.  They  live  in  a  collection  of  dirty  huts  made  of  bamboo 
and  mud ;  they,  nevertheless,  appear  to  be  happy  and  contented,  and  in  general  are  well 
conducted.  The  men  with  pickaxes  work  their  way  into  the  guano,  leaving  a  sort  of  wall 
on  either  side,  {fip.  325  ;)  here  it  is  so  hard  that  it  requires  a  heavy  blow  to  remove  it.  It 
is  then  conveyed  "in  wheelbarrows  either  direct  to  the  mouths  of  the  shoots  on  the  edge  of 
the  cliffs,  or  to  the  huge  carts  running  on  tramways  for  the  same  purpose.  The  color  varies 
very  much — in  some  parts  being  as  dark  as  warm  sepia,  and  in  others  as  light  as  that  of  a 
Bath  brick. 

The  smell  of  ammonia  is  said  to  be  very  powerful,  so  much  so,  in  fact,  as  to  affect 
the  eyes  of  the  workmen ;  crystalline  deposits  of  various  ammoniacal  salts  are  also  found 
amongst  the  guano.  The  guano  heaps  are  surrounded  by  a  high  fence  to  prevent  its  being 
blown  away  by  the  wind,  near  the  mouths  of  the  canvas  tubes  or  shoots,  which  are  some- 
times TO  feet  long,  through  which  it  is  conducted  to  the  boats.     See  Jig.  326. 

326 


As  in  Peru,  the  surface  of  the  guano  is  covered  with  skeletons  of  birds,  and  bones  of 
seals.  It  is  also  perforated  by  numberless  holes,  running  in  every  direction,  like  a  rabbit 
warren.  These  are  made  by  a  bird  about  the  size  of  a  pigeon,  which  remains  iiidden  during 
the  day,  sallying  forth  at  dark  to  fish.  Gold  and  silver  ornaments  are  also  discovered  occa- 
sionally, having  been  buried  by  the  ancient  inhabitants  more  than  three  centuries  ago. 

It  is  quite  unnecessary  here  to  insist  on  the  value  of  guano  as  a  manure.  This  is  a 
point  established  beyond  all  question  by  nearly  every  agriculturist  in  the  kingdom  ;  and 
recorded  by  all  classes  of  writers  on  agricultural  subjects ;  it  has  been  the  means,  moreover, 
of  converting  the  sandy  desert  around  Lima  into  a  soil  capable  of  raising  abundant  crops  of 
maize  ;  hence  the  Peruvian  proverb,  "  Iluano,  though  no  saint,  works  many  miracles." 

*  On  Guano.    Journal  of  tho  Agricultural  Society  of  England,  vol.  ii.  p.  815. 


588 


GUANO. 


Commercial  varieties. — The  following  appear  to  be  the  chief : — 

1.  Peruvian.  5.  Saldanha  Bay 

2.  Angamos.  6.  Kooria  Mooria. 

3.  Ichaboe.  7.  African. 

4.  Patagonian.  8.  Indian. 

Chemistry. — Guano  being  an  article  of  so  great  value  to  the  agriculturist  as  a  manure, 
and  being  liable  not  only  to  adulteration  to  a  very  great  extent,  but  also  varying  when  genuine 
considerably  in  quality,  it  is  highly  important  to  have  some  means  of  ascertaining  its  value. 
Tliis  cannot  be  done  satisfactorily  by  ever  so  experienced  a  dealer  by  mere  inspection,  and, 
therefore,  both  for  the  buyer  and  the  seller,  resort  is  necessary,  for  a  knowledge  of  its  com- 
pound parts,  to  the  analysis  of  the  chemist.*  Such  being  the  case,  we  must  first  ascertain 
the  composition  of  genuine  guano,  and  then  inquire  upon  which  of  its  several  constituents 
its  value  as  a  manure  depends. 

The  constilution  of  guano  is  exhibited  by  the  following  analysis  of  three  sorts  by  Den- 
ham  Smith. 

American  GfAXO. — Analysis  of  three  sorts  by  Denham  Smith. 
1.    Constituents  soluble  in  hot  water,  {in  100  parts  of  guano.) 


I. 

II. 

III. 

Phosphate  of  lime 

0-186 

. 

0110 

Phosphate  of  soda 

0-120 

Phosphate  of  ammonia  and  magnesia     - 

0-564 

0-784 

0-133 

Uric  acid 

2-516 

Urate  of  ammonia 

15-418 

Organic  matter 

1-180 

0-860 

0-756 

2.   Constituents  soluble  in  cold  water,  (in  100  parts.) 


I. 

II. 

III. 

Water 

Sulphate  of  potash 

Sulphate  of  soda   ------ 

Phosphate  of  potash 

Phosphate  of  soda 

Phosphate  of  ammonia           .         .         -         - 

Phosphate  of  lime 

Oxalate  of  ammonia 

Oxalate  of  soda 

Chloride  of  potassium 

Cidorlde  of  sodium        -..-•- 
Chloride  of  ammonium           -         .         .         - 
Organic  matter 

22-200 
8-00 

6-S3 

7-40 

2-55 
1-500 

20-420 

23-944 
7-732 

6-124 

9-39 

0-668 

7-700 

19-177 
4-947 
3-60 

10-563 
4-163 

28-631 
3-030 
2-553 

8.    Constituents  insoluble  in  ivater,  («i  100  parts.) 


I. 

II. 

III. 

Phosphate  of  lime 

19-750 

6-270 

13113 

Phosphate  of  magnesia          -         .         -         - 

2-030 

0-874 

2-580 

Oxalate  of  lime 

2-560 

10-958 

Sand,  &c.       - 

15-60 

0-720 

0-420 

Peroxide  of  iron  and  alumina 

- 

- 

0-150 

Humus 

2-636 

0-862 

0-836 

Organic  matter      ------ 

3-456 

Water 

- 

4-974 

Loss 

0-044 

0-498 

Valuable  as  these  elaborate  analyses  are  in  a  scientific  point  of  view,  they  are  quite  un- 
necessary for  practical  purposes  in  ascertaining  the  value  of  any  given  sample,  for  on  which 
of  these  various  constituents  does  the  chief  efficacy  of  guano  depend  ? 

*  liebig's  "Chemistry  in  its  applications  to  Agriculture  and  Physioloiry,"  p.  272. 


GUANO. 


589 


Ammonia. — Undoubtedly  one  0/ <Ae  most,  if  not  the  most,  important  constituents  of 
guano  is  the  ammo7ua.  Authors  differ  as  to  the  precise  manner  in  which  ammonia  and  its 
salts  act  in  promoting  the  growth,  and  especially  in  the  development  of  the  nitrogenized 
compounds  of  plants ;  but  the  fact  is  placed  beyond  dispute,  whether  it  be  that  the  ammo- 
nia contained  in  the  air  is  decomposed  by  the  leaves,  or  that  the  salts  of  ammonia  are  ab- 
sorbed by  the  spongioles  of  the  roots  in  solution  in  water.  Now,  it  is  quite  possible  that, 
in  the  mysterious  economy  of  the  life  of  the  plant,  the  ammonia  may  perform  a  slightly 
different  function  when  in  different  states  of  combination,  either  with  hydrochloric,  sul- 
phuric, nitric,  phosphoric,  carbonic,  uric,  humic,  or  oxalic  acids ;  and  although,  as  a  gen- 
eral rule,  we  should  be  inclined  to  yield  the  palm  in  point  of  utility  to  the  more  soluble 
combinations,  yet  all  experience  goes  to  show  that  the  value  of  an  ammouiacal  manure  may 
be  measured  chiefly,  if  not  entirely,  by  the  quantity  of  that  compound  present,  and  is  in  a 
great  measure  independent  of  its  state  of  combination. 

Dr.  Ure  drew  a  distinction  between  what  he  called  the  actual  and  potential  ammonia, 
i.  c,  between  ammonia  and  ammouiacal  salts  ready  formed,  and  compounds,  such  as  uric 
acid,  which  during  their  decay  are  gradually  converted  into  ammonia.  It  appears  that 
recent  guano  contains  from  3  to  5  per  cent,  of  uric  acid,  whilst  the  older  deposits  contain 
generally  less  than  1  per  cent.  No  doubt  the  guano  at  the  time  of  its  deposition  consisted 
chiefly  of  uric  acid  ;  and  it  is  this  uric  acid  which  has  become  converted  into  salts  of  am- 
monia ;  for  the  excrements  of  birds  which  live  chiefly  on  fish  are  found  to  contain  from  50 
to  80  per  cent,  of  uric  acid.  It  is  also  an  established  truth  in  agricultural  chemistry  that  a 
manure  which  contains  bodies  capaljle  of  gradually  yielding  up  any  valuable  compound, 
such  as  ammonia,  are  more  useful  than  those  which  contain  that  compound  ready  formed, 
and  in  the  state  of  soluble  combinations,  which  the  first  storm  of  rain  may  wash  away  from 
the  roots  of  the  plants,  where  they  are  required.  Nevertheless,  admitting  the  truth  of  all 
this,  the  writer  is  of  opinion  (and  he  believes  this  is  the  general  experience  of  agricul- 
turists) that  the  importance  of  this  distinction  between  actual  and  potential  ammonia  has 
been  rather  exaggerated  ;  and  that  generally  it  is  enough  for  all  practical  purposes,  in  esti- 
mating the  value  of  a  guano,  to  determine  the  total  quantity  of  nitrogen  present  in  every 
form,  and  to  consider  it  as  representing  an  equivalent  quantity  of  ammonia  "  in  esse"  or 
"  in  posse." 

Potash. — Of  the  two  alkalies,  potash  and  soda,  the  soil  usually  contains  more  than  suf- 
ficient soda  for  the  supply  of  vegetation  ;  it  is  therefore  chiefly  potash  which  it  is  necessary 
to  add  in  the  form  of  manure. 

Besides,  even  the  best  guano  always  contains  a  considerable  quantity  of  common  salt, 
viz.,  from  1-0  to  2-5  and  even  5  percent. 

Mr.  Way,  in  his  valuable  paper,  "  On  the  Composition  and  Value  of  Guano,"  only  gives 
the  quantity  of  alkaline  salts,  not  having  determined  the  potash ;  but  the  average  quantity 
of  potash  in  genuine  guano  may  be  seen  by  referring  to  the  analyses  before  given  in  detail, 
and  will  be  found  to  vary  from  3  to  4  per  cent. 

However,  in  estimating  the  value  of  guano  the  knowledge  of  the  quantity  of  potash  is 
by  no  means  of  the  same  importance  as  of  the  ammonia,  or  the  phosphoric  acid. 

Phosphoric  Acid. — The  phosphoric  acid  is  second  in  importance  to  no  other  constituent 
than  the  ammonia ;  being  essential  for  the  development  of  the  seeds  and  all  those  parts  of 
the  vegetable  organism,  which  serve  as  foods  in  the  production  and  restoration  of  the  flesh 
and  bones  of  animals.  It  exists  in  the  guano  (as  is  shown  by  the  preceding  detailed  anal- 
yses) in  combination  with  ammonia,  potash,  soda,  and  lime. 

In  most  analyses  the  quantity  of  phosphate  of  lime,  3CaO,PO',  is  given  instead  of  phos 
phoric  acid,  PO^  or  3H0,P0^ ;  but  156  parts  of  phosphate  of  lime  (3CaO,PO'*)  correspond 
to  12  of  phosphoric  acid  (PO'*),  or  as  13  to  6. 

The  amount  of  phosphate  of  lime  in  the  several  varieties  of  guano  is  as  follows : — 


I 

Mnxfmum.      Minimum. 

Me.m. 

I'erutu'a?!.. 

From  analyses  of  9  samples  by  Way,  imported  in  1847-8 

From  Mr.  Way's  analyses  of  10  samples,  imported  in  1S48-9    - 

From  Mr.  Way's  analyses  of  14  samples,  imported  in  1S49 
AngamoK. 

From  2  analyses  by  Dr.  Uro        -        -        .        .                 .        . 
lehaboe. 

From  11  analyses  by  Dr.  Uro  and  Mr.  Teschomacher 
Patagonitm. 

From  analyses  of  14  samples  by  Dr.  Ure  and  Mr.  Tesehemacher 
Saldanha  Buy. 

From  analyses  of  9  samples  by  Mr.  Way 

From  analyses  of  9  samples  by  Dr.  Ure  and  Mr.  Teschcmacbcr 
Kooria  Mooria. 

From  analyses  of  3  s.imples  by  Mr.  Ncsliit         .... 

From  analyses  of  3  samples  by  Mr.  Aiyohn       .... 

84-45 
25-30 
28-98 

2200 

87-00 

65-5 

6090 
62  5 

25-50 
23-50 

19-46 
21-31 
21-23 

13-50 

26-00 

29-3 

49-01 
510 

2-80 
5-34 

26-95 
23-30 
25-13 

20-25 

81-50 

47-4 

54-93 
5G-7 

14-15 
17-17 

590 


GUANO. 


25-12 

Patagonian   - 

-     47-4 

20-25 

Saldanha  Bay 

-     55-84 

31-50 

Kooria  Mooria 

-     15-66 

So  that  the  average  quantity  of  phosphate  of  lime  in  the  several  specimens  is  as 
follows : — 

Peruvian 
Angamos 
Ichaboe 

These  facts  are  very  suggestive  as  showing  how  guano,  by  exposure  to  air  and  moisture, 
has  the  ammoniacal  salts  washed  out,  at  the  same  time,  as  a  consequence,  increasing  tlie 
ratio  of  phosphates. 

Organic  Matter. — The  amount  of  organic  matter  in  guano,  other  than  ammonia  and  its 
salts,  is  of  no  great  importance  in  estimating  its  value  as  a  manure.  Not  unfrequcntly  the 
amount  of  organic  matter,  containing  uric  acid  or  ammoniacal  saUs,  is  stated  in  analyses,  as 
organic  matter  "  Wf/t  in"  or  '■'■containing  amniotiia  ;  "  but  it  is  obvious  sucli  analyses  are 
nearly  worthless,  the  value  of  the  guano  depending  essentially  on  the  quantity  of  nitrogen, 
cither  existing  as  ammoniacal  salts  or  capable  of  being  converted  into  them.  Good  guano 
contains  on  an  average  about  50  per  cent,  of  ash  (mineral  matters)  and  50  per  cent,  of 
combu.stible  (organic)  matters. 

Sand. — The  knowledge  of  the  proportion  of  sand  in  a  guano  is  of  some  importance  as 
determining  its  purity  or  otherwise.  It  is  easy  to  understand  how  a  deposit  like  guano, 
existing  often  near  the  sea-shore,  and  frequently  on  a  sandy  soil,  should  contain  a  certain  ad- 
mixture of  sand.  Some  specimens  are  almost  free  from  it,  and  few  genuine  specimens  con- 
tain more  than  1  to  2  per  cent. 

Common  Salt. — The  presence  of  common  salt  in  a  guano  need  not  surprise  us.  It  is 
doubtless  derived  from  the  sea,  partly  through  the  medium  of  the  birds  themselves,  and 
partly  from  the  evaporation  of  the  salt  spray  continually  driven  upon  the  coasts  by  the 
wind.  It  is  variable  in  quantity,  as  we  should  expect  from  a  knowledge  of  its  origin,  rang- 
ing in  samples  of  genuine  guano  from  1  to  5  per  cent.  Although  common  salt  has  been 
shown*  to  possess  a  certain  power  of  absorbing  ammonia,  yet  this  is  but  transient,  and  the 
efficacy  of  guano  cannot  be  said  to  depend  to  any  extent  upon  the  sea  salt  present  in  it. 
The  knowledge  of  its  amount  is  of  great  importance,  since  the  guano  is  not  unfrequcntly 
adultei-atcd  with  salt. 

Water. — Obviously  the  larger  the  amount  of  water  present  in  guano,  the  smaller  will  be 
the  proportion  of  valuable  constituents  in  a  given  weight.  Genuine  guano  contains  on  an 
average  from  10  to  about  20  per  cent,  of  water.  Many  of  the  salts  in  guano  are  likewise 
deliquescent,  so  that  it  has  a  tendency  to  become  moi.st  by  exposure  to  the  air ;  and 
this  tendency  to  absorb  moisture  is  an  element  of  value  in  the  manure,  especially  in  dry 
seasons. 

Calculation  of  the  moneij  value  of  guano  from  the  resnlta  of  anahiHes. — In  a  most  im- 
portant and  interesting  paper  "  On  the  value  of  artificial  manurcs,"f  Mr.  Way  arrives 
at  certain  money  values  for  ammonia,  phosphoric  acid,  and  the  various  constituents 
of  guaao  and  other  manures,  by  a  comparison  with  the  cost  of  these  several  compounds 
in  their  ordinary  commercial  salts.  These  numbers  will  be  found  most  valuable  to  the 
agriculturist  in  drawing  his  own  conclusions  respecting  the  value  of  a  guano  or  other 
manure  from  the  results  of  analysis  furnished  to  him  by  the  chemist.  They  are  as 
follows : — 

Ammonia £56  per  ton. 

Pota.-;!! 31       " 

Phosphate  of  lime  (insoluble) 7       " 

Phosphate  of  lime  (soluble) 32" 

Organic  matter  .-....-l" 

and  tnc  following  example  of  their  application  may  prove  useful. 

Calculation  of  the  money  value  of  guano,  as  deduced  from  the  cost  of  its  several  constit- 
uents in  their  commercial  salts,  applied  to  the  mean  composition  of  Peruvian  guano 
deduced  by  5Ir.  Way  from  78  analyses  : — 
100  tons  contain 
Ammonia     -----     16-5     at 
Organic  matter      .         -         -         .     52-0     " 

Potash 3-5     " 

Insoluble  phosphate  of  lime  -         -     23"0     " 
Soluble  phosphate  of  lime     -        -      7-0     " 


£ 

£ 

56  per  ton 

930 

1 

52 

31       " 

108 

7       " 

161 

32       " 

224 

Value  of  100  tons 


£1,475 


Or  per  ton 


£14     15     0 


*  A.  B.  'Northcote,  on  the  Function  of  Salt  in  Agriculture,  Phil.  Mag.  x.  170. 
t  Agricultural  Journal,  xvi.  533. 


Gmr  COTTON.  591 

Hence  it  is  obvious  that  whilst  guano  was  selling  at  £11  per  ton,  it  was  more  economical 
and  convenient  to  employ  it  than  to  make  an  artificial  mixture  of  its  chemical  constituents; 
but  now  that  the  price  has  risen  to  about  £14  per  ton,  it  becomes  a  question  whether  it 
will  not  be  possible  to  produce  an  artificial  compound  having  equal  value  as  a  manure  which 
will  compete  in  price  with  the  guano. 

Impurities  and  Adulterations. — In  consequence  of  the  high  price  of  guano,  the  great 
demand  for  it,  and  the  ease  with  which  the  unwary  farmer  may  be  imposed  upon,  guano  is 
adulterated  with  various  substances,  and  to  a  great  extent.  Impositions  even  have  been 
practised  by  selling  as  genuine  guano  artificial  mixtures,  made  to  look  so  much  like  guano 
that  the  farmer  would  scarcely  detect  it.  The  writer  recollects  examining  a  guano  which 
contained  50  per  cent,  of  sand,  and  no  less  than  25  per  cent,  of  sea  salt ;  and  Dr.  Ure  gives 
the  following  analysis  of  an  article  sent  to  him,  which  had  been  offered  to  the  public  by  ad- 
vertisement as  Peruvian  guano  which  contained — 

Common  salt 32'0 

Sand  .- 28-0 

Sulphate  of  iron 5'2 

Phosphate  of  lime       -    ' 4'0 

Organic  matter  (irom  bad  guano  to  give  it  smell)          -         -     23'3 
Moisture '7"5 

100-0 
In  fact,  so  numerous  and  vaiious  are  the  tricks  played  with  guano,  that  unless  a  sample 
is  submitted  to  a  skilful  chemist  for  analysis  before  purchase,  we  would  strongly  recommend 
the  agriculturist  to  purchase  of  no  one  but  dealers  of  unquestionable  honor. 

Professor  Johnstone  observes  :  "  Four  vessels  recently  sailed  hence  for  guano  stations, 
ballasted  with  gypsum,  or  plaster  of  Paris.  This  substance  is  intended  for  admixture  with 
guano,  and  will  enable  the  parties  to  deliver  from  the  vessel  a  nice-looking  and  light-col- 
ored article.  The  favorite  material  for  adulterating  guano  at  the  present  moment,  is  umber, 
which  is  brought  from  Anglesea  in  large  quantities.  The  rate  of  admixture  is,  we  are  in- 
formed, about  15  cwts.  of  umber  to  about  5  cwts.  of  Peruvian  guano,  from  which  an  ex- 
cellent-looking article,  called  African  guano,  is  manufactured." 

GUN  COTTOX.  (Syn.  Fi/roziline ;  Fulmicoton,  Fr.)  In  1833  M.  Braconnot  dis- 
covered that  starch,  by  the  action  of  monohydrated  nitric  acid,  became  converted  into  a 
peculiar  substance  which  dissolved  in  excess  of  the  acid,  and  was  rcprecipitated  in  a  granu- 
lar state  on  the  addition  of  water.  This  substance,  known  as  xyloidine,  when  washed  and 
dried,  was  found  to  explode  on  contact  of  a  light,  and  even  if  heated  to  356°.  It  also  ex- 
ploded if  subjected  to  a  smart  blow.  The  subsequent  researches  of  M.  Pelouze  indicated 
this  singular  body  to  be  starch,  C'^IP°0'°,  in  which  one  equivalent  of  hydrogen  is  replaced 
by  peroxide  of  nitrogen,  or  hyponitric  acid.     The  formula  of  xyloidine  would  consequently 

be      ^Tr)4  \  0".     On  the  supposition  of  this  being  the  correct  formula,  100  parts  of  starch 

should  yield  127-7  of  xyloidine,  and  M.  Pelouze  obtained  from  128  to  130.  About  thir- 
teen years  subsequently  to  the  discovery  of  xyloidine,*M.  Schonbein  announced  his  discov- 
ery of  gun  cotton.  Chemists  immediately  saw  the  analogy  between  the  two  substances,  for 
while  xvloidine  appears  to  be  derived  from  starch  by  the  substitution  of  one  equivalent  of 
hyponitric  acid  for  one  of  hydrogen,  gun  cotton  is  derived  from  cellulose  (C'-II'"0'°,  isomeric 
with  starch)  by  the  substitution  of  two  or  three  equivalents  of  hyponitric  acid  for  the  same 
number  of  equivalents  of  hydrogen. 

Preparation. — Gun  cotton  can  be  prepared  in  several  ways.  The  most  simple  consists 
in  immersing,  for  a  few  seconds,  well-carded  cotton  in  a  mixture  of  equal  ]iarts  by  volume 
of  oil  of  vitriol  of  the  specific  gravity  1-845,  and  nitric  acid  of  the  specific  gravity  1-500. 
The  cotton,  when  well  saturateij,  is  to  be  removed  ;  and,  after  l)eing  squeezed  to  repel  as 
much  as  possible  of  the  excess  of  adhering  acid,  well  washed  in  clean  cold  water.  As  soon 
as  the  water  no  longer  reddens  litmus  paper,  the  washing  may  be  considered  sufficient. 
The  gun  cotton  thus  prepared  is  cautiously  dried  at  a  heat  not  exceeding  212°.  It  is  safer 
to  dry  at  about  150°.  The  cotton  prepared  by  this  means  explodes  well,  but  does  not 
always  dissolve  easily  in  ether.  If,  consccjuently,  it  is  desired  to  prepare  a  very  soluble 
cotton  for  photographic  collodion,  the  following  process  may  be  eniploye<l,  in  which,  instead 
of  nitric  acid,  dry  nitre  is  used. 

A\  ounces  pine  dry  nitre  in  fine  powder. 

30  drams  (fluid  measure)  sulphuric  acid,  sp.  gr.  1-845. 

120  grains  of  well-carded  cotton. 
The  cotton  is  to  be  well  pulled  out  ami  immersed  in  the  mixture  of  the  nitre  and  sul- 
phuric acid.     The  contact  with  the  acid,  iS;c.,  is  to  be  insured  l)y  stirring  and  pulling  out  the 
cotton  with  two  glass  rods.     As  soon  as  perfect  saturation  is  effected,  whicli,  with  good 
management,  will  be  in  about  one  minute,  the  cotton  is  to  be  tin-own  into  a  large  pan  of 


592  GUNNERY. 

water  and  well  rinsed.  The  vessel  is  to  be  continued  under  a  tap  until  litmus  paper  is  no 
longer  reddened.  The  cotton  is  to  be  squeezed  in  the  folds  of  a  clean  towel,  and  exposed 
(after  being  again  well  pulled  out)  to  a  gentle  heat  to  drj.  It  is  curious  that  the  most 
soluble  cotton  is  often  the  least  explosive,  although  there  is  reason  to  believe  that  the  most 
soluble  cotton  is  that  which  nearest  approaches  in  constitution  to  tri-nitro  cellulose. 

M.  Schonbein  recommends  a  mixture  of  one  measure  of  nitric  acid  with  three  measures 
of  sulphuric  acid  as  the  best  bath  for  the  cotton.  The  liquid  is  to  be  allowed  to  cool  previous 
to  its  immersion.  He  also  saturates  the  cotton  with  nitrate  of  potash,  by  immersing  it  in  a 
solution  of  that  salt  before  drying.  Cotton  prepared  in  this  manner  is  not  adapted  for 
photographic  purposes,  but  it  is  highly  explosive,  and,  therefore,  well  fitted  for  blasting 
rocks. 

The  true  constitution  of  gun  cotton  is  by  no  means  well  established.  It  appears  to  be 
very  liable  to  differ  in  composition  according  to  the  method  of  preparation.  According  to 
M.  Bechamp  it  is  essential,  in  order  to  obtain  a  cotton  both  fulminating  and  soluble  in  ether, 
to  operate  upon  the  mixture  of  nitre  and  sulphuric  acid  before  the  temperature  (which  rises 
on  the  ingredients  being  mingled)  has  fallen.  If  cooling  has  takeii  place  previous  to  the 
immersion  of  the  cotton,  the  resulting  pyroxiline  is  fulminating,  but  insoluble  in  ether. 

The  analyses  of  MM.  Domonte  and  Menard,  and  also  of  AI.  Bechan^p,  agree  best  with 
bi-nitro  cellulose,  while  those  of  Gladstone,  Vankerchoff',  and  Reuter,  Schmidt  and  Hecker 
and  Pelouze  are  more  in  accordance  with  a  tri-nitro  cellulose.  To  add  to  the  difficulty  of 
forming  a  conclusion  on  the  subject,  M.  Peligot's  analyses  agree  best  with  the  expression 

CVO''^^  V  0",  which  is  that  of  bi-nitro  glucose. 

According  to  M.  Bechamp  xyloidine  and  pyroxiline  are  acted  on  by  protacetate  of  iron, 
the  original  substance  being  regenerated.     Thus  xyloidine  affords  starch,  and  pyroxiline 
cotton.     The  regenerated  cotton  was  analyzed  with  the  following  result : — 
Experiment.  CalculatioD. 


Carbon     -         -     43-35         C"  =  72         44-44 
Hydrogen         -       6-31         H'"    10  6-17 

Oxygen    -         -     50-34         0'"     80         49-39 

100-00  162      100-00 

Explosive  substances  analogous  to  gun  cotton  may  be  prepared  from  many  organic 
bodies  of  the  cellulose  kind,  by  immersing  them  in  the  same  bath  as  for  gun  cotton. 
Among  these  may  be  mentioned  paper,  tow,  sawdust,  and  calico. 

When  collodion  is  wanted  for  an  application  to  cut  surfaces,  and  the  cotton  is  with  dif- 
ficulty soluble  in  alcoholic  ether,  a  solution  may  easily  be  obtained  if  the  cotton  be  first 
moistened  with  acetic  ether  and  the  alcoholic  ether  be  afterwards  added. 

Several  of  the  nitro-derivatives  of  starch  and  cellulose  undergo  spontaneous  decompo- 
sition when  kept  for  some  time  in  stoppered  bottles. — {Gladstone.) — C.  G.  W. 

GUNNERY.  Under  the  head  of  Artillery,  we  have  included  nearly  every  point  with 
which  it  appears  necessary  to  deal  in  a  work  of  this  description.  It  is  convenient,  how- 
ever, to  say  a  few  words  in  this  place  of  Sir  William  Armstrong's  gun.  Instead  of  being 
cast  like  ordinary  cannon,  or  formed  of  several  longitudinal  pieces  lika  the  Whitworth 
cannon,  or  of  a  hooped  or  wire-bound  tube,  as  proposed  by  Captain  BlaKely,  Mr.  Mallet, 
and  others,  the  new  gun  is  formed  of  an  internal  steel  tube,  bound  over  with  strips  of 
rolled  iron,  laid  on  spirally,  somewhat  after  the  fashion  of  small-arm  barrels,  the  alternate 
strips  being  laid  in  opposite  directions,  so  that  the  joints  may  cross  each  other,  or,  in  other 
words,  so  as  to  "  break  joint."  This  system  of  construction  is,  of  course,  expensive,  but  it 
gives  great  strength  with  a  very  small  quantity  of  metal.  The  internal  steel  tube  is  rifled 
in  a  very  peculiar  manner.  Instead  of  having  two,  three,  or  four  grooves,  like  ordinary 
rifled  guns,  or  being  formed  with  an  oval  bore  like  that  employed  by  Mr.  Lancaster,  or 
with  a  polygonal  bore,  as  in  the  Whitworth  system,  it  has  a  very  large  number  of  small 
grooves  close  to  each  other,  no  less  than  40,  we  believe,  in  a  gun  of  2^  inches'  bore.  The 
shot  or  shell  Mr.  Armstrong  usually  makes  of  cast  iron,  of  about  three  diameters  in 
length,  and  covers  it  entirely  over  with  thin  lead,  so  that  it  may  readily  conform  itself  to 
the^rifled  interior  of  the  bore  when  forced  forward  by  the  explosion  of  the  charge.  Pro- 
vision for  loading  the  gun  at  the  breech  is  made  by  cutting  a  slot  near  the  breech  euddown 
from  the  upper  side  into  the  bore,  of  a  sufficient  length  to  admit  the  elongated  projectile 
and  the  charge  of  powder,  and  of  a  breadth  slightly  greater  than  the  diameter  of  the  bore. 
The  bore  itself  is  also  slightly  enlarged  where  it  opens  into  the  space  formed  by  cutting  out 
the  slot,  in  order  that  the  projectile  and  powder,  after  being  lowered  into  the  slot,  may  be 
easily  pressed  forward  by  hand  or  other  means  into  the  bore.  In  order  to  close  the  space 
formed  by  the  slot  after  the  gun  is  charged,  a  movable  breech-piece  is  formed  to  fit  into  it, 
and  is  furnished  with  two  handles,  by  means  of  which  it  may  be  lifted  out  or  dropped  into 
its  place  as  required.     The  breech-piece  has  fitted  to  its  front  face  a  facet  of  copper,  a  por- 


GUNPOWDER. 


593 


tion  of  which  projects  slightly,  so  as  to  form  a  disc  which,  when  the  breech-piece  is  forced 
a  little  forward,  will  enter  the  bore  behind  the  charge,  and  by  its  expansion,  at  the  moment 
of  explosion  prevent  all  escape  of  gas.  The  slight  forcing  forward  of  the  breech-piece  is 
effected  by  means  of  a  strong  screw  passing  in  through  the  extreme  breech  end  of  the  gun, 
and  pressing  against  the  rear  end  of  the  breech-piece.  This  screw  is  turned  by  a  hand 
lever.  *  The  fore  end  of  the  breech-piece  is  bored  out  at  the  centre,  the  bore  extending 
through  the  copper  disc,  and  into  this  bore  is  placed,  at  the  time  of  loading,  a  small  dis- 
charging cartridge.  The  "  touch-hole,"  or  hole  for  the  detonating  plug,  is  formed  in  the 
breech-piece,  passing  down  from  its  upper  side  into  its  bore ;  so  that  when  the  piece  is  to 
be  discharged,  the  detonating  cap  or  plug  is  struck,  the  small  discharging  cartridge  is  there- 
by fired,  and  its  fire  is  instantaneously  communicated  to  the  main  cartridge  in  the  bore  of 
the  gun  itself.  With  his  shells  Mr.  Armstrong  uses  a  percussion  fuze  of  his  invention  for 
causing  the  shell  to  burst  on  striking  an  object,  in  case  the  striking  takes  place  before  the 
time-fuze  has  operated.  In  a  cylindrical  case  within  the  shell  Mr.  Armstrong  fixes  a  weight 
or  striker,  by  means  of  a  pin  passing  through  it  and  the  sides  of  the  case.  This  pin  is. cut 
or  broken  by  the  shock  which  the  projectile  receives  in  the  gun  at  the  instant  of  firing, 
and  the  striker,  being  thus  liberated,  recedes  to  the  rear  end  of  tlie  case,  and  there  remains 
until  the  velocity  of  the  shell  is  checked  by  coming  into  contact  with  some  object.  When 
this  takes  place,  the  striker,  not  participating  in  the  retardation  of  the  shell,  advances  in 
the  case,  and  causes  a  patch  of  detonating  composition  to  be  carried  suddenly  against  a 
fixed  point,  which  fires  the  composition  and  ignites  the  bursting  charge  in  the  shell. 

Experiments  have  shown  that  a  32-pounder  gun,  constructed  upon  Mr.  Armstrong's 
system,  has  a  greater  range  and  fires  with  greater  accuracy  than  any  gun  at  present  in  use 
in  tlie  navy ;  and  yet,  while  the  former  weighs  but  26  cwt.,  the  present  weighs  no  less  than 
95  cwt.  We  may  therefore  at  once  reduce  the  weight  of  our  uaval  guns  by  nearly  three- 
fourths,  without  impairing  their  range  or  aim.  This  would  enormously  increase  the  facility 
of  handling  them,  and  therefore  leave  us  free  to  greatly  reduce  the  number  of  men  em- 
ployed to  work  them.  Again,  with  the  breech-loading  arm  it  would  probably  be  found 
possible  to  get  rid  of  the  running  out  and  in  of  the  gun  while  in  action,  by  counteracting 
the  recoil  in  some  suitable  way ;  and  for  this  reason,  also,  the  number  of  men  required  to 
work  them  might  be  very  much  below  the  present  staff.  Again,  both  the  bore  and  the 
thickness  of  the  metal  of  the  gun  being  greatly  reduced,  the  external  diameter  of  the  gun 
will  be  so  small  that  very  small  ports  only  would  bo  necessary,  and  this  would  add  matei-ially 
to  the  safety  of  the  gunners,  especially  in  close  action.  Another  advantage  might  be  gained 
in  the  use  of  certain  guns,  particularly  the  bow-chase  guns,  on  board  ship.  It  is  always 
a  matter  of  great  difficulty  to  give  such  a  form  to  the  ship  that  the  muzzles  of  these  may, 
when  the  guns  are  run  out,  project  sufficiently  far  to  carry  the  fire  of  the  explosion  clear 
of  the  vessel.  With  the  long,  slight  Armstrong  gun  this  difficulty  would  not  be  ex- 
perienced. 

GUNPOWDER.  The  discovery  of  gunpowder  has  been  claimed  for  Roger  Bacon  and 
Schwartz.  The  ground  for  this  appears  to  be  no  more  than  this :  In  their  writings  the 
earliest  recorded  mention  of  the  discovery  is  made  in  any  European  language.  Roger 
Bacon,  unquestionably  antecedent  to  his  German  rival,  was  born  1214,  and  died  1292  ;  and 
his  work,  "  De  Nullitate  Magiaj,"  appears  to  have  been  written  about  1270,  while  Kircher'a 
account  gives  1354  as  the  date  of  the  discovery  by  Schwartz.  It  appears,  however,  that  an 
Arabic  manuscript  exists  in  the  collection  of  tlie  Escurial,  which  unmistakably  describes 
gunpowder  and  its  properties,  the  date  of  which  is  anterior  to  1250. — Jfallct. 

This  well-known  composition  is  employed  for  charging  the  numerous  varieties  of  fire- 
arms. Its  use  depends  upon  the  fact  that,  at  the  moment  of  ignition,  violent  deflagration 
takes  places,  accompanied  by  the  evolution  of  a  large  volume  of  gas.  It  is  evident  that 
if  the  explosion  occurs  in  a  limited  space,  a  vast  pressure  accumulates  and  becomes  a  pro- 
pulsive force.  The  gas  produced  by  the  explosion  of  good  gunpowder  occupies  nearly  900 
times  the  volume  of  the  powder  itself;  but,  owing  to  the  high  temperature,  the  space  oc-  ' 
cupied  by  the  gas  at  the  moment  of  formation,  is  probably  nearly  2,700  times  greater  than 
the  volume  of  the  powder.  One  of  the  most  popular  errors,  i-egarding  the  projectile  force 
of  explosive  substances,  arises  from  the  extremely  vague  meaning  generally  attached  to  the 
words  strong,  powerful,  and  other  equivalent  terms.  It  is  this  which  leacfs  so  many  to 
imagine  the  possibility  of  attaining  marvellously  long  ranges  by  means  of  the  various  ful- 
minating substances  known  to  chemists.  The  latter  are  unfit  for  use  in  fire-arms,  owing  to  a 
variety  of  circumstances.  One  of  them  is  the  extreme  rapidity  of  their  explosion.  The  wliole 
mass  appears  to  be  converted  into  gas  at  once,  whereas  in  gunpowder  the  ignition  proceeds 
from  particle  to  particle.  The  action  of  fulminates  is  also  too  local ;  if  a  portion  of  any  of 
the  more  violently  explosive  sub.stances  be  fired  on  a  piece  of  metal,  the  latter  will  be  per- 
forated or  depressed  exactly  at  the  spot  occupied  by  the  substance,  and  if  it  be  attempted  to 
use  it  to  charge  fire-arms,  they  will  be  destroyed,  and  yet,  in  all  proI)ability,  the  bullet  not 
projected.  Moreover,  it  is  impossible  to  use  fulminates  successfully  for  cliarging  shells,  be- 
cause the  latter,  instead  of  being  blown  to  pieces  of  moderate  size,  capable  of  inflicting 
Vol.  III.— 38 


594  GUNPOWDER. 

large  wounds  and  throwing  down  buildings,  become  converted  into  fragments  so  small  as 
to  be  far  less  destructive.  The  escape  of  the  Emperor  of  the  French,  from  a  recent  at- 
tempt at  his  assassination,  was  probably  owing  to  this  circumstance. 

It  has  been  found  that  no  composition  fulfils  so  many  requisites  for  charging  fire-arms 
as  a  mixture,  in  due  proportions,  of  sulphur,  nitre,  and  charcoal.  It  is  this  composition 
which,  in  the  form  of  small  grains,  more  or  less  polished,  constitutes  gunpowdert  The 
latter  should  possess  several  properties  which,  although  sometimes  tending  in  opposite  di- 
rections, are  not  entirely  incompatible,  aTid  may  therefore  be  nearly  attained  in  practice. 
Some  of  the  principal  of  these  are  the  following  :  1.  The  proportions  should  be  so  adjusted 
that  the  combustion  may  be  complete,  and  little  residue  be  left  after  explosion.  2.  The 
powder  should  be  as  little  hygrometric  as  possible.  3.  It  should  be  sufficiently,  but  not  too 
explosive.  4.  It  should  be  hard  and  dense  enough  to  bear  carriage  without  breakage  of  the 
grains. 

Too  great  a  proportion  of  carbon  and  sulphur  will  cause  rapid  fouling  of  the  gun,  and 
the  explosive  force  will  be  less  than  it  should  be ;  too  small  a  proportion  of  sulphur  will 
render  the  powder  too  hygrometric.  The  presence  of  soda' or  chloride  of  potassium  in  the 
nitre  will  lead  to  the  same  fault.  The  powder  must  be  sufiiciently  stamped,  or  it  will  not 
possess  the  fourth  requisite. 

The  history  of  gunpowder  may  be  conveniently  studied  under  the  following  heads : — 

Preparation  of  the  ingredients. 

Mixture  and  granulation. 

Modes  of  estimating  projectile  force. 

Analysis  of  gunpowder. 

Preparation  of  the  Tngredtents. 

Preparation  of  tke  nitre. — The  nitre  employed  for  powder  is  always  in  a  state  of  almost 
absolute  purity,  especially  as  regards  the  presence  of  the  chlorides  of  potassium  or  sodium. 
The  crude  nitre  of  commerce  contains  several  impurities,  among  which  are  found  nitrates 
of  soda  and  lime,  chlorides  of  potassium  and  sodium,  and  sulphates  of  potash  and  soda. 
They  are  all  removed  by  crystallization.  The  principal  impurity  is  common  salt.  The  pro- 
cess of  purification  is  founded  on  the  fact  that  the  latter  substance  is  almost  equally  soluble 
in  hot  or  cold  water,  whereas  nitre  is  far  more  soluble  in  hot  than  in  cold  water.  The  fol- 
lowing is  the  French  mode  of  refining  saltpetre:  1,200  kilogrammes  are  gently  heated 
with  600  litres  of  water  in  a  copper  boiler.  The  solution  is  constantly  stirred  and  skimmed, 
and  more  nitre  is  added,  until  the  total  quantity  is  3,000  kilogrammes.  As  soon  as  the 
whole  is  added,  and  it  is  presumed  that  all  the  nitre  is  dissolved,  the  common  salt  is  removed 
from  the  bottom  of  the  boiler.  The  solution  is  now  to  be  clarified  with  glue.  For  this 
purpose  400  litres  of  water  are  added  by  small  portions,  and  then  1  kilogramme  of  the 
glue  dissolved  in  hot  water.  The  scum,  which  soon  rises,  is  removed,  and  the  fluid  is  boiled 
until  clear.  The  whole  is  then  allowed  to  cool  to  about  194°,  and  the  solution  of  nitre  is 
carefully  decanted  from  the  layer  of  common  salt  into  the  crystallizing  vessel.  The  latter 
is  a  large  shallow  pan  with  sloping  sides.  The  fluid  is  constantly  stirred  as  it  cools,  in  order 
that  the  crystals  formed  may  be  very  small ;  this  is  done  in  order  to  facilitate  the  washing 
process,  and  also  because  the  fine  powdery  crystals  are  well  adapted  for  admixture  with  the 
other  ingredients.  When  the  crystallizing  solution  is  cold,  the  nitre  is  removed  to  boxes 
containing  false  bottoms,  pierced  with  holes.  The  aperture  in  the  bottom  of  the  box  (be- 
low the  false  bottom)  being  closed,  a  saturated  solution  of  pure  nitre  is  poured  on  the  crys- 
tals to  dissolve  out  the  chloride  of  sodium.  Being  already  saturated,  it  is  evident  it  cannct 
dissolve  any  of  the  nitre.  After  remaining  two  hours  in  contact  with  the  nitre,  the  solu- 
tion is  allowed  to  run  off,  and  when  the  dropping  has  almost  entirely  cease(],  the  process 
of  washing  is  repeated,  substituting  pure  water  for  the  solution  of  nitre.  The  product  is 
dried  at  a  gentle  heat,  being  constantly  stirred  to  enable  it  to  retain  the  pulvenilent  form. 
Tiie  power  (above  alluded  to)  possessed  by  a  saturated  solution  of  nitre,  of  dissolving  other 
Kilts  has  been  taken  advantage  of  in  one  of  the  processes  for  analyzing  saltpetre.  Some 
manufacturers  fuse  the  nitre  after  it  has  been  purified  by  crystallization.  This  process  has 
several  -disadvantages,  among  others  that  of  necessitating  machinery  to  reduce  it  again 
to  a  pulverulent  state. 

Preparation  of  the  sulphur. — Sulphur  maybe  purified  for  the  gunpowder-maker  by  two 
processes.  In  the  first  the  crude  article  is  fused  in  an  iron  pot,  so  contrived  that  the  fire 
does  not  play  directly  on  the  bottom,  but  only  round  its  sides.  The  lighter  impurities  aie 
to  be  removed  by  skimming,  while  the  heavier  sink  to  the  bottom.  The  temperature  should 
not  be  allowed  to  rise  much  above  232°,  for  it  then  becomes  sluggish,  and  at  320°  it  is  so 
thick  as  to  prevent  the  impurities  from  being  removed. 

Sulphur  may  be  more  readily  and  economically  purified  by  distillation.  The  apparatus 
for  the  purpose  is  exceedingly  simple  in  principle  ;  but  the  process  requires  care,  and  is 
not  entirely  free  from  danger.  As  it  is  not  intended  to  obtain  the  sulphur  in  the  state  of 
flowers,  the  apparatus  for  condensation  is  not  required  to  be  kept  cold  ;  in  fact,  the  still  is 
purposely  placed  so  near  to  the  chamber  of  condensation,  that  the  sulphur  may  l)e  received 


GUNPOWDER.  595 

in  the  fluid  state.  There  are  several  points  which  must  be  attended  to  in  the  construction 
of  an  apparatus  for  the  distillation  of  sulphur  ;  they  are  as  follows  :  1.  The  crude  sulphur 
must  be  capable  of  being  introduced,  and  the  refined  product  removed  easily,  without  air 
being,  at  the  same  time,  permitted  to  enter  the  still  or  condenser.  2.  Free  means  of  egress 
for  the  heated  air  must  be  provided.  3.  The  contrivance  for  the  latter  purpose  must  not 
allow  fresh  air  to  return.  4.  The  process  must  be  continuous.  The  still  and  condenser 
employed  in  France  for  the  purification  of  crude  sulphur  fulfils  all  these  conditions.  The 
still  is  in  the  form  of  a  very  wide-necked  tubulated  retort,  made  of  cast  iron.  It  is  set  in 
brickwork  over  a  furnace,  and  opens  into  a  square  brick  chamber  surmounted  by  a  dome. 
The  latter  has  a  rather  short  chimney  over  it,  containing  a  valve  opening  upwards  to  permit 
escape  of  the  heated  air,  but  not  allowing  any  thing  to  return.  Over  what  may  be  termed 
the  tubulature  of  the  retort  or  still,  is  placed  an  iron  pot  with  a  tube  communicating  with 
it.  The  pot  is  heated  by  the  same  fire  that  works  the  still.  The  crude  sulphur  is  placed  in 
the  pot  where  it  melts,  and  by  raising  a  plug,  which  closes  the  tubulature,  may  be  made  to 
enter  the  still.  The  pipe  forming  the  tubulature  rises  a  short  distance  above  the  bottom 
of  the  iron  supply  pot.  This  is  in  order  that  any  heavy  mechanical  impurities  may  sink 
to  the  bottom,  and  not  enter  the  still,  and  unnecessarily  clog  it.  If  the  pot  be  always  kept 
full  of  melted  sulphur,  and  the  latter  is  permitted  to  enter  by  raising  the  plug,  it  is  evident 
that  no  air  will  find  its  way  into  either  the  retort  or  condenser.  It  is  exceedingly  important 
tliat  this  should  be  the  case,  because  violent  explosions  are  liable  to  occur  if  the  highly 
heated  vapor  of  sulphur  comes  in  contact  with  an  oxidizing  medium,  such  as  atmospheric 
air,  which  would  convert  it  into  sulphurous  acid.  The  melted  sulphur  which  collects  on 
the  floor  of  the  chamber  is  allowed  to  flow  out  when  desired,  by  means  of  an  iron  plug  at- 
tached to  a  rod  of  the  same  metal.  The  sulphur  is  not  allowed  to  run  out  entirely,  so  as 
to  permit  air  to  enter,  for  the  rea.son  stated  above.  The  loss  occurring  during  the  purifica- 
tion is  owing  partly  to  oxidation,  resulting  in  the  formation  of  sulphurous  acid,  and  partly 
to  the  fixed  impurities  contained  in  the  crude  material. 

Preparation  of  the  charcoal. — Of  the  three  ingredients  of  gunpowder,  the  most  im- 
portant is  generally  considered  to  lie  the  charcoal.  Unfortunately  the  woods  which  are 
best  adapted  for  the  production  of  pyroligneous  acid,  are  not  fitted  for  the  manufacture  of 
gunpowder ;  the  charcoal  must,  therefore,  be  prepared  specially.  The  following  are  the 
essential  properties  of  good  charcoal  for  powder :  1.  It  should  be  light  and  porous.  2. 
It  should  yield  little  ashes.  3.  It  should  contain  little  moisture.  The  woods  yielding  good 
powder  charcoals  are  black  alder,  poplar,  spindle  tree,  black  dogwood,  and  chestnut. 
Hemp  stalks  are  said  to  yield  good  charcoal  for  gunpowder.  The  operation  of  preparing 
the  charcoal  naturally  divides  itself  into  three  processes.  1.  The  selection  of  the  wood. 
2.   Preparation  of  the  wood  previous  to  carbonization.     3.  The  carl)onization. 

In  selecting  the  wood  care  is  to  be  taken  to  avoid  the  old  branches,  as  the  charcoal 
made  from  them  would  yield  too  much  ashes.  The  bark  is  to  be  rejected  for  the  same 
reason.  The  wood  is  to  be  cut  into  pieces  from  4J  feet  to  6  feet  long.  If  the  branches 
used  are  more  than  f  of  an  inch  in  diameter  they  are  to  be  split.  If  the  wood  be  too 
large,  great  difficulty  will  be  found  in  uniformly  charring  it. 

There  are  two  methods  employed  in  the  charring  of  wood  for  gunpowder.  In  one,  the 
operation  is  conducted  in  pits  ;  but  the  process  more  commonly  resorted  to  is  distillation  in 
cylindrical  iron  retorts.  There  are  certain  advantages  in  the  pit  process,  but  tiiey  are 
more  than  counterbalanced  by  the  convenience  and  economy  of  distillation.  The  stills 
used  are  al)out  6  feet  long,  and  2  feet  9  inches  in  diameter.  The  ends  of  the  cylinders  are 
closed  Ijy  iron  plates,  pierced  to  admit  tubes  of  the  same  metal.  Some  of  the  latter  are 
for  the  introduction  during  the  carbonization  of  sticks  of  wood,  which  are  capable  of  being 
removed  to  indicate  the  stage  of  the  decomposition,  while  another  communicates  with  the 
condenser.  The  more  freely  the  volatile  matters  are  allowed  to  escape,  the  better  tlie 
quality  of  the  resulthig  charcoal.  If  care  be  not  taken  in  this  respect,  especially  as  the 
distillation  reaches  its  close,  the  tarry  matters  become  decomposed,  and  a  hard  coating  of 
carbon  is  deposited  on  the  charcoal,  which  greatly  lowers  its  quality.  The  process  of  burn- 
ing in  pits  is  considered  to  yield  a  superior  coal,  owing  to  the  facility  with  which  the  gases 
and  vapors  fly  off. 

The  degree  to  which  the  burning  or  distillation  is  carried  materially  influences  the  na- 
ture of  the  resulting  powder.  If  tlic  operation  be  arrested  before  the  charcoal  becomes 
quite  black,  so  that  it  may  retain  a  dark-brownish  hue,  tlie  powder  will  he  more  explosive 
than  it  would  l)e  if  it  were  puslied  until  the  charcoal  had  attained  a  <l('c|)  lilack  color.  \Vlien 
it  has  been  found  that  no  more  volatile  products  are  being  given  off,  the  fire  is  damped, 
and  in  a  few  hours  the  contents  of  the  cylinders  arc  transferred  to  well  closed  iron  boxes  to 
-cool. 

MixTURK  Axn  Granulation. 

A  very  considerable  number  of  methods  have  been  employed  at  various  times,  for  effect- 
ing that  thorougli  incorporation  of  the  ingredients  necessary  for  the  production  of  a  good 
powder.     The  oldest  method  consists  in  stamping  the  materials  in  wooden  mortars.     Tlio 


596 


GUNPOWDER. 


pestles  are  square  shafts  of  wood  ending  in  brass  beaters.  The  mortars  are  of  wood,  and  so 
shaped  that  any  of  the  composition  which  may  be  forced  upwards  by  tlie  blows  of  the  stamp- 
ers falls  back  to  the  bottom.  In  order  to  prevent  fracture  of  the  mortars,  a  piece  of  wood 
of  the  toughest  kind  should  be  let  in  on  the  spot  where  the  pestle  falls.  The  pestles  are 
raised  by  means  of  cogs  fixed  on  a  shaft,  driven  by  a  water-wheel  or  steam-engine. 

One  of  the  many  methods  adopted  to  mix  the  nitre,  sulphur,  and  charcoal,  is  by  means 
of  drums  containing  metallic  balls ;  but  this  arrangement  is  inferior  to  tha^  where  edge 
stones  are  employed.  This  last  is  superior  to  all  others,  the  product  being  not  only  very 
dense,  and,  therefore,  capable  of  enduring,  without  becoming  pulverulent,  the  motion  un- 
avoidable in  carrying  it  about,  but  it  is  also  thoroughly  incorporated.  It  is,  of  course,  es- 
sential that  the  stones,  and  the  bed  on  which  they  work,  should  not  strike  fire  during  work. 
To  secure  this,  they  are  sometimes  made  of  calcareous  stone,  and  sometimes  of  cast  iron. 
Previous  to  being  subjected  to  the  action  of  the  mill,  the  ingredients  must  be  pulverized  and 
mixed.  The  pulverization  may  conveniently  be  effected  in  wooden  drums  containing  metal- 
lic balls.  The  pulverized  materials,  after  being  sifted  or  bolted,  and  weighed  out  in  the 
proper  proportion,  are  to  be  inserted  in  a  mixing  drum,  containing  on  its  inside  pieces  of 
wood  projecting  inwards,  so  that,  as  it  revolves,  complete  admixture  gradually  takes  place. 
Tiie  product  of  the  last  operation  is  now  ready  to  be  laid  on  the  bed  of  the  mill.  During 
the  grinding,  the  cake  is  kept  moist  by  the  addition,  at  proper  intervals,  of  enough  water  to 
make  it  cohere.  As  the  stones  revolve,  a  scraper  causes  the  material  to  take  such  a  posi- 
tion that  it  cannot  escape  their  action.  The  cake  produced  by  the  action  of  the  stones  is 
ready  for  graining  or  corning.  For  this  purpose  the  cake  is  subjected  to  powerful  pressure, 
by  means  of  a  hydraulic  press.  The  mass  is  then  broken  up  and  transferred  to  a  species  of 
sieve  of  skin  or  metal  pierced  with  holes.  A  wooden  flail  is  ]ilaced  on  the  fragments,  and 
the  sieves  are  violently  agitated  by  machinery.  By  this  means  the  grains  and  dust  produced 
by  the  operation  fall  through  the  holes  in  the  skin  or  metal  disks,  and  are  afterwards  sepa- 
rated by  sifting.  Sometimes  the  machinery  is  so  arranged  that  the  graining  and  separation 
of  the  meal  powder  are  effected  at  one  operation.  The  meal  powder  is  reworked,  so  as  to 
convert  it  into  grains.  The  next  operation  to  which  the  powder  is  subjected  is  glazing.  Its 
object  is  to  render  it  less  liable  to  injury  by  absorption  of  moisture  or  disintegration  during 
its  carriage  from  place  to  place.  The  glazing  is  effected  by  causing  the  grained  powder  to 
rotate  for  some  time  in  a  wooden  drum  or  cjlinder,  containing  rods  of  wood  running  from 
end  to  end.  The  grains,  as  they  rub  against  each  other,  and  against  the  wooden  ribs,  have 
their  angles  and  asperities  rubbed  off",  and  at  the  same  time  the  surface  becomes  harder  and 
polished.    It  is  finally  dried  by  exposure  to  a  stream  of  air,  heated  by  means  of  steam. 

A  vast  number  of  experiments  have  been  made,  at  various  times,  to  discover  the  pro- 
portions of  nitre,  sulphur,  and  charcoal  best  adapted  for  the  production  of  gunpowder.  It 
has  been  found,  as  might  have  been  anticipated,  that  no  general  rule  can  be  given,  no  ad- 
mixture can  be  made  which  shall  fulfil  every  requirement.  Those  powders  which  contain 
the  largest  quantities  of  charcoal  are,  it  is  true,  as  powerful  as  others  in  projectile  force,  but 
they  have  the  disadvantage  of  attracting  more  humidity  from  the  air.  It  is  very  singular  that 
all  nations  appear  to  have  found,  by  trial,  the  proportions  most  generally  useful  for  ordinary 
purposes,  and  it  is  worthy  of  remark  that  they  all  approximate  to  the  percentages  required 
by  the  very  simple  formula,  KO,NO^  +  S  4-  3C. 

MoDKs  OF  Estimating  the  Projectile  Force  of  Gunpowder. 

The  usual  mode  of  determining  the  propulsive  force  of  powder  is  by  ascertaining  the 
distance  to  which  it  can  throw  a  ball  of  known  weight.  The  instrument  used  in  this  coun- 
try for  this  purpose  consists  of  an  8-inch  mortar  charged  with  2  ounces  of  powder,  the  balls 
being,  in  each  case,  of  the  same  size  and  weight.  The  French  use  for  the  purpose  an  iron 
mortar,  elevated  at  an  angle  of  45°.  The  mortar  is  7"5  inches  in  diameter.  The  ball  is  of 
bronze,  and  is  only  O-OGV  inches  smaller  than  the  bore  of  the  gun ;  the  windage  is,  conse- 
quently, very  small.  The  charge  of  powder  being  3 '2  ounces,  and  the  weight  of  the  ball 
05  ll)s.,  the  latter  should  be  thrown  not  less  than  43'7'5  yards. 

The  force  of  powder  may  also  be  estimated  by  means  of  an  instrument  called  a  pendu- 
lum gun.  It  consists  of  a  gun  barrel  hung  at  the  lower  end  of  a  pendulum,  so  arranged 
that  the  amount  of  angular  deviation  caused  by  the  recoil  may  be  measured  ;  the  balls  may 
also  be  fired  into  a  cup  suspended  to  a  similar  pendulum.  The  data  obtained  serve  to  en- 
able the  rapidity  of  motion  of  the  ball,  at  the  moment  of  discharge,  to  be  calculated  by 
means  of  formula)  contrived  for  the  purpose. 

On  the  Analysis  of  Gunpowder. 
Several  methods  have  been  given  by  various  chemists  for  the  analysis  of  gunpowder ; 
the  following,  on  the  whole,  appears  the  most  effective  :  The  percentage  of  water  is,  in  the 
first  place,  to  be  determined,  by  drying  in  vacuo  over  sulphuric  acid,  imtil  no  more  diminu- 
tion of  weight  occurs.  The  dried  powder,  or  a  fresh  quantity,  is  tlicn  to  be  washed  on  a 
filter  with  boiling  water,  until  nothing  more  is  dissolved  out.  The  residue  is  to  l)e  dried 
below  212"  and  weighed  ;  the  loss  is  tlie  nitre.     If  preferred,  the  solution  of  the  nitre  may 


HEAT.  597 

be  evaporated  to  dryness,  and  the  residue  weighed.  The  mixture  of  charcoal  and  sulphur 
is  then  to  be  digested  in  a  stoppered  flask  with  bisulphide  of  carbon  ;  this  will  dissolve  out 
the  sulphur  and  leave  the  charcoal.  The  loss  of  weight  of  the  dry  mixture  of  sulphur  and 
charcoal  will  enable  the  percentages  of  charcoal  and  sulphur  to  be  calculated.  If  it  be  de- 
sired to  know  the  quality  of  the  charcoal,  a  combustion  of  it  may  be  made  with  a  mixture 
of  chromate  of  lead  and  bichromate  of  potash.  Ordinary  charcoal  contains  from  69  to  74 
of  carbon,  3-9  to  5-5  hydrogen,  0-5  to  3-0  per  cent,  ashes.  It  has  been  attempted  to  dis- 
solve out  the  sulphur  with  sulphite  of  soda  or  caustic  potash ;  but  these  methods  involve 
several  sources  of  error. 

Good  gunpowder  should  not  lose  more  than  1  per  cent,  of  moisture  on  drying.  It  should 
not  leave  alkaline  globules  when  exploded  on  a  clean  metallic  plate.  The  specific  gravity 
of  a  good  powder  should  not  be  less  than  1-755  ;  it  is  sometimes  as  high  as  1-840.  The 
denser  the  powder  the  better  it  endures  transportation.  As  the  density  cannot  be  taken  in 
water,  owing  to  the  solubility  of  the  nitre,  turpentine  or  benzole  must  be  substituted,  a  cor- 
rection being  made  for  the  difference  in  density  of  the  fluid  medium. — C.  G.  W. 

GUTTA  PERCHA.  In  1848  Dr.  Faraday  drew  the  attention  of  experimentalists  to  the 
highly  insulating  power  of  gutta  percha,  which  not  only  possesses  this  property  under  or- 
dinary circumstances,  but  likewise  retains  it  under  atmospheric  conditions  which  would 
make  the.surfuce  of  glass  a  good  conductor.  This  has  led  to  its  almost  universal  adoption 
as  the  insulator  for  the  wires  of  the  electrical  telegraph.  When  buried  in  the  earth,  unless 
it  is  attacked  by  insects,  or  by  a  fungus,  it  retains  its  high  insulatory  power,  and  we  have 
every  reason  for  believing  that  gutta  percha  does  not  undergo  a  cliange  when  immersed  in 
sea  water.  It  has,  however,  been  found,  that  when  it  has  been  exposed  to  the  intense  sun- 
shine of  India,  it  undergoes  a  remarkable  change ;  oxygen  is  absorbed,  the  gutta  percha 
loses  its  coherence,  and  at  the  same  time  its  powers  of  insulation. 

H 

HARDENING.  The  process  by  which  metals  are  rendered  harder  than  they  are  when 
they  first  leave  the  hands  of  the  workman. 

Some  metals  are  hardened  by  hammering  or  rolling ;  but  care  is  required  not  to  carry 
this  too  far,  as  brittleness  may  be  induced.  Sudden  cooling  is  had  recourse  to  with  some 
metals.  Pure  hammered  iron  appears,  after  annealing,  to  be  equally  soft,  whether  suddenly 
or  slowly  cooled  ;  some  of  the  impure  kinds  of  malleable  iron  harden  by  immersion.  Steel, 
however,  receives  by  sudden  cooling  that  extreme  degree  of  hardness  combined  with  tenaci- 
ty, which  places  it  so  incalculably  beyond  every  other  material  for  the  manufacture  of  cut- 
ting tools. 

In  hardening  and  tempering  steel,  there  are  three  things  to  be  considered,  namely,  the 
means  of  heating  the  objects  to  redness,  the  means  of  cooling  the  same,  and  the  means  of 
applying  the  heat  for  tempering^  or  "  letting  them  down."  It  is  not  possible  in  this  work 
to  enter  into  the  manipulatory  details  of  liardening  steel  for  various  purposes ;  the  most 
valuable  information  on  this  subject  is  given  in  Ho'tzapffers  work  on  Turniuf/  and  Mechan- 
ical Manipulation. 

Steel  pens  are  hardened  by  being  heated  in  large  quantities  in  iron  trays  within  a  fur- 
nace, and  then  plunged  in  an  oily  mixture  ;  generally,  they  are  likewise  tempered  in  oil,  or 
a  composition,  the  boiling  point  of  which  is  the  same  as  the  temperature  suited  to  "  letting 
them,  down." 

Saws  and  springs  are  hardened  in  various  compositions  of  oil,  suet,  wax,  and  other  ingre- 
dients, "  whicli,  however,  lose  their  hardening  property  after  a  few  weeks'  constant  use." 
Steel  plates  are  hardt^ncd  occasionally  by  allowing  water  to  fall  on  them  when  hot. 

Case  hardening  is  the  process  by  which  wrought  iron  is  first  converted  exteriorly  into 
steel,  and  is  subsequently  hardened  to  that  particular  depth,  leaving  the  central  parts  in 
their  original  condition  of  soft  and  fibrous  iron.  The  principal  agents  used  for  case  harden- 
ing are  animal  matters,  as  the  hoofs,  horns,  bones,  and  skins  of  animals.  The  prussiate  of 
potash,  which  is  a  compound  of  carbon  and  nitrogen,  is  also  employed  for  case  hardening. 
In  principle  it  is  the  same  as  the  animal  substances.  Tlie  iron  is  lieated  in  the  open  fire  to  a 
dull  red,  and  the  prussiate  is  either  sprinkled  upon  it  or  rubbed  on  in  the  lump  ;  it  is  re- 
turned to  the  fire  for  a  few  minutes,  and  immersed  in  water.  In  the  volume  of  Lardner's 
"  Cyclopaedia,"  on  Iron  and  Steel,  edited  by  Robert  Hunt,  the  subjects  of  hardening  and 
tempering  are  treated  in  a  practical  manner. 

IIE.VT.  The  Force  or  Principle  upon  which  the  conditions,  relatively,  of  solid,  fluid, 
and  aeriform  states  depend.     That  which  jjroduces  the  sensation  of  warmth. 

The  discussion  of  the  habit\ides  of  heat  with  the  dillerent  kinds  of  matter  belongs  to 
physico-chemical  science,  and  will  ))e  treated  of  in  Uvc'k  Dictionary  of  Cfiemixtrt/.  It  will 
suffice  in  this  place  to  state  succinctly  those  laws  which  have,  more  directly,  a  bearing  on 
any  of  our  manufacturing  processes. 


598  HELIOGEAPHY. 

Heat  and  tnotive  power  are  mutually  co7ivertible,  and  heat  requires  for  its  production, 
and  produces  by  its  disappearance,  motive  power  in  the  proportion  of  772  foot-powids  for 
each  Fahrenheit  unit  of  heat. — Rankine. 

This  unit  of  heat  has  beeu  established  by  Dr.  Joule  to  be  the  amount  of  heat  required  to 
raise  the  temperature  of  one  pound  of  liquid  water  by  one  degree  of  P'ahrenheit.  A  falling 
weight,  or  any  other  mode  of  motion,  produces  a  definite  quantity  of  heat  according  to  this 
law. 

If  the  total  actual  heat  of  a  homogeneous  and  uniformly  hot  substance  be  conceived  to  he 
divided  into  any  n'unibers  of  equal  parts,  the  effect  of  those  parts  in  causiny  icork  to  be 
performed  will  be  equal. — liankine. 

Or,  in  other  words,  of  a  given  equivalent  of  heat,  from  whatever  source  produced,  the 
work  which  it  can  ett'oct  is  always  an  equal  and  constant  quantity. 

Heat  may  I)e  produced  by  friction,  as  we  see  in  the  development  of  it,  powerfully,  in 
the  axles  of  railway  carriages,  insufficiently  lubricated.  By  the  attrition  of  two  pieces  of 
wood  ignition  can  be  obtained. 

Heat  is  developed  in  the  mixture  of  bodies  of  different  densities,  such  as  spirits  of  wine 
and  water,  or  sulphuric  acid  and  water,  there  being  a  diminution  of  volume  in  each  case. 

Heat  is  produced  by  many  conditions  of  chemical  combination,  in  numerous  cases  so 
energetically  as  to  produce  intense  combustion  and  even  explosion. 

Heat  is  obtained  by  combustion  for  our  ordinary  manufacturing  processes  and  domestic 
uses.  This  is  a  chemical  union  of  one  body  with  another,  as  carbon  with  oxygen;  but  to 
effect  this  an  excitant  appears  necessary,  or  a  continually  increasing  excitement  of  the  energy 
upon  which  heat  depends,  as  the  application  of  liame  in  one  case,  and  the  phenomena  of 
spontaneoiis  combustion  in  another. 

Electricity,  by  its  disturbing  power,  developes  heat ;  and  this  all-important  force  is  also 
rendered  manifest  by  the  processes  of  vitality,  (vital  or  nervous  force.) 

Dr.  Joule  has  clearly  shown  that,  whatever  may  be  the  source  of  heat,  a  ceitain  fixed 
elevation  of  temperature  is  produced  by  a  given  amount  of  mechanical,  chemical,  electrical, 
or  vital  disturbance,  and  that  the  mechanical  value  of  the  cause  producing  the  heat  is  exactly 
represented  by  the  mechanical  effect  obtained. 

For  a  full  discussion  of  this  important  point,  see  the  Memoirs  of  Joule,  of  Thomson,  and 
of  Rankine,  in  the  Philosophical  Transactions  of  London  and  Edinburgh.  The  applications 
oi'  heat  will  be  found  under  the  proper  heads. 

HELIOGRAPHY  was  the  name  given  by  M.  Niepce  to  his  process  for  obtaining,  through 
the  agency  of  the  solar  rays  upon  plates  of  metal  or  glass  covered  with  resins,  the  impres- 
sion of  external  objects.  The  process  has  been  employed  of  late  years  in  preparing  litho- 
graphic stones,  and  steel  or  copper  plates,  for  receiving  photographic  impressions,  which 
might  be  subsequently  printed  from.  The  name  hcliography  is  a  far  more  appropriate  one 
than  photography ;  but  the  latter  has  become  too  permanently  fixed  in  our  language  to 
leave  any  hope  of  our  returning  to  the  former. 

HEMATITE  {Fer  Oligiste,  Fr. ;  Rothcisenstein,  Germ.)  is  a  native  reddish-brown  per- 
oxide of  iron.  Tiiis  term  was  applied  to  this  ore  of  iron  by  the  ancients  on  account  of  the 
red  color  of  its  powder,  from  a^fxa,  blood. 

This  species  includes  specular  iron  and  the  old  red  iron  ore.  "The  varieties  of  a  sub- 
metallic  or  non-metallic  lustre  were  included  under  the  names  of  red  hematite,  fibrous  red 
iron,  or  of  soft  and  earthy  red  ochre,  and  when  consisting  of  slightly  coherent  scales,  scaly 
red  iron  or  red  iron  froth.'''' — {Dana.')  Dana  also  includes,  most  injudiciously  as  it  appears, 
reddle  or  red  chalk,  and  jaspery  clay  iron  ore,  with  some  others,  among  the  hematites. 

HENBANE.  The  Jlyosciamus  niyer.  Henbane  is  a  plant  used  in  medicine,  from  which 
modern  chemistry  has  extracted  a  new  crystalline  vegetable  principle  called  hyosciamine, 
which  is  very  poisonous,  and  when  applied  in  solution  to  the  eye,  determines  a  remarkable 
dilatation  of  the  pupil,  as  belladonna  also  does. 

HONES  AND  HONE  SLATES.  These  are  slaty  stones  which  are  used  in  straight 
pieces  for  sharpening  tools  after  they  have  been  ground  on  revolving  grindstones.  The 
more  important  varieties  are  the  following: 

Tlie  Norumy  Raystone,  which  is  the  coarsest  variety  of  the  hone  slates,  is  imported  in 
large  quantities  from  Norway.  In  Charnwood  Forest,  near  Mount  Sorrel,  in  Leicestershire, 
particularly  from  the  Whittle  Hill  quarry,  are  obtained  the  Charnley  Forest  Stone,  said  to  be 
one  of  the  best  substitutes  for  the  Turkey  oilstone,  and  it  is  much  in  request  by  joiners  and 
others.  Ayr  stone.  Snake  stone,  and  Scotch  stone,  aie  used  especially  for  polishing  copper 
plates.  Tiie  Welsh  oilstone  is  almost  in  equal  repute  with  the  Charnley  Forest  stone;  it  is 
obtained  from  the  vicinity  of  Llyn  Idwall,  near  Snowdon,  and  hence  it  is  sometimes  called 
Idwall  stone.  From  Snowdon  is  also  obtained  the  cufler\i  green  sto7ie.  The  Devonshire 
oilstones,  obtained  near  Tavistock,  which  were  introduced  by  Mr.  John  Taylor,  are  of  ex- 
cellent quality,  but  the  supply  of  them  being  irregular  they  have  fallen  into  disuse. 

The  German  razor  hone  has  been  long  celebrated.  It  is  obtained  from  the  slate  moun- 
tains in  the  neighborhood  of  Ratisbon,  where  it  occurs  in  the  form  of  a  yellow  vein  running 


HYDRAULIC  CRANES.  599 

through  the  blue  slate,  varying  in  thickness  from  1  to  18  inches.  When  quarried  it  is  sawn 
into  thin  slabs,  and  these  are  generally  cemented  to  slices  of  slate,  which  serve  as  a  support. 
Sometimes,  however,  the  yellow  and  the  blue  slate  are  cut  out  naturally  combined.  There 
are  several  other  hone  stones,  which,  however,  require  no  particular  notice. 

The  Turkey  oilstone  is  said  to  surpass  in  its  way  every  other  known  substance,  and  it 
possesses  in  an  eminent  degree  the  property  of  abrading  the  hardest  steel ;  it  is,  at  the  same 
time,  of  so  compact  and  close  a  nature  as  to  resist  the  pressure  necessary  for  sharpening  a 
graver,  or  any  instrument  of  that  description.  There  are  white  and  black  varieties  of  the 
Turkey  oilstone,  the  black  being  the  hardest,  and  it  is  imported  in  somewhat  larger  pieces 
than  the  white ;  they  are  found  in  the  interior  of  Asia  Minor,  and  are  brought  down  to 
Smyrna  for  sale. 

HORSE  CHESTNUT.  {Marronnier  D'Inde,  Fr. ;  Gemeine  JiossJcasfa7iie,  Germ.) 
The  wood  of  this  well-known  tree  is  used  by  the  Tunbridge  turner.  It  is  only  em- 
ployed for  some  large  varnished  works. 

HORSESHOES.  The  ordinary  method  of  making  these  is  well  known.  There  has, 
however,  been  lately  introduced  with  much  success  a  machine  for  making  horseshoes. 
One  of  these  machines  has  been  erected  at  Chillington  Ironworks,  Wolvei'hampton,  by  the 
inventor,  Mr.  Henry  Burden,  of  Troy,  New  York.  As  early  as  1835  he  took  out  a  patent 
for  a  machine  for  making  horseshoes,  which  he  improved  upon  in  1843,  and  this  was 
turned  to  practical  account  by  the  production  of  a  considerable  number  of  horseshoes. 
The  present  machine,  however,  which  was  patented  in  1857,  is  entirely  different  from  the 
former  ones,  and  is  a  very  remarkable  piece  of  mechanism.  In  the  previous  machines  the 
piece  of  iron  bar  of  which  the  shoe  was  to  be  made  was  rolled  into  shape  before  being 
bent,  and  the  pressure  of  the  rollers  being  in  the  direction  of  its  length,  the  bar,  when  it 
was  pressed,  was  naturally  rather  extended  in  length  than  width,  and  the  widening  which 
is  required  at  the  crown  of  the  shoe  was  not  properly  effected.  By  the  present  plan  the 
bar,  after  being  heated,  enters  the  machine  by  a  feeding  apparatus,  a  piece  of  the  required 
length  is  cut  off,  and,  by  a  stroke  from  a  piece  of  steel  shaped  like  the  inside  of  a  horse- 
shoe, is  bent,  and  falls  upon  a  die  on  awheel  beneath,  corresponding  to  one  on  a  cylinder 
above,  and  thus  acquires  by  pressure  the  desired  shape,  two  lateral  strikers  at  the  same 
moment  hitting  the  extremites,  or  heels,  of  the  shoe,  and  driving  them  inwards  into  the 
required  shape.  Thence  it  passes  between  another  pair  of  dies,  where  it  is  stamped  and 
by  an  ingenious  arrangement  is  flattened  from  the  curled  shape  which  the  wheel  gives 
it  as  it  falls  at  the  mouth  of  the  machine.  The  shoes  thus  made  are  remarkable  for  their 
exactness  in  shape  and  in  the  position  of  the  holes — a  most  important  point  with  regard 
to  the  safety  of  horses'  feet;  and  they  can  be  produced,  when  the  machine  is  in  proper 
order,  at  the  rate  of  60  per  minute,  which  is  more  than  two  men  can  forge  in  a  day,  and 
the  superiority  over  shoes  forged  by  hand  is  very  striking.  As  the  bar  is  bent  before 
being  pressed  in  the  die,  the  pressure  at  the  crown  is  in  the  direction  of  the  width,  and 
hence  the  widening  is  readily  effected. 

HYDRAULIC  CRANES.  The  application  of  water-pressure  to  cranes  is  due  to  Sir 
"Wm.  Armstrong.  These  are  now  so  generally  applied,  that  although  the  subject  belongs 
properly  to  engineering,  it  is  thought  advisable  to  include  some  notice  of  these  valuable 
and  interesting  machines  in  this  work.  A  statement  made,  by  the  request  of  the  British 
Association  in  1854,  by  the  inventor  himself,  so  completely  explains  all  the  peculiarities 
of  these  cranes,  that  the  paper  is  reproduced  from  the  reproceedings  of  the  Association. 

"  The  employment  of  water-pressure  as  a  mechanical  agent  having  recently  under- 
gone a  great  and  rapid  development,  I  may  be  permitted  to  make  a  few  observations  on 
the  successive  steps  by  which  its  present  importance  has  been  attained.  In  so  doing  I 
shall  commence  with  the  year  1846,  in  which,  after  many  preliminary  experiments,  I  suc- 
ceeded in  establishing,  upon  the  public  quay  at  Newcastle-upon-Tyne,  the  hydraulic 
crane  which  has  formed  the  basis  of  what  has  since  been  effected. 

"  This  crane  both  lifted  the  weight  and  swung  round  in  either  direction  by  the  pressure 
of  water,  and  was  characterized,  like  all  other  hydraulic  cranes  since  made,  by  remark- 
able precision  and  softness  of  movement,  combined  with  great  rapidity  of  action. 

"The  experiment  thus  made  at  Newcastle  having  proved  satisfactory,  I  soon  after- 
wards obtained  authority,  through  the  intervention  of  Mr.  Hartley,  the  Dock  Surveyor  of 
Liverpool,  to  construct  several  cranes  and  hoists  upon  the  same  principle  at  the  Albert 
Dock  in  that  town,  where  they  were  accordingly  erected,  and  have  ever  since  continued 
in  operation. 

"The  next  place  at  which  these  cranes  were  adopted  was  Grimsby  New  Dock,  where 
an  important  step  in  the  advancement  of  this  kind  of  nuichinery  was  made  on  the  sug- 
gestion of  Mr.  Rendel,  who  pointed  out  its  applicability  to  the  opening  and  closing  of 
dock  gates  and  sluices,  and  instructed  me  to  extend  its  application  to  those  objects. 
An  extensive  system  of  water-pressure  machinery  was  accordingly  carried  out  at  that 
dock,  and  the  result  afforded  the  first  practical  demonstration  tliat  the  pressure  of  a 
colunm  of  water  could  be  advantageously  applied  as  a  substitute  for  manual  labor,  not 


600 


HYDRAULIC  CRANES. 


raerely  for  the  cranage  of  goods,  but  also  to  give  safe  and  rapid  effect  to  those  mechani- 
cal operations  which  are  necessary  for  passing  ships  through  the  entrance  of  docks. 

"  In  all  these  instances  the  moving  column  of  water  was  about  200  feet  in  elevation. 
At  Newcastle  and  Liverpool  the  supply  was  derived  from  the  pipes  communicating  with 
the  town  reservoirs,  but  at  Grimsby  a  tower  was  built  for  supporting  a  tank  into  which 
water  was  pumped  by  a  steam-engine.  In  the  former  cases,  the  fluctuation  of  pressure, 
consequent  upon  the  variable  draught  from  the  pipes  for  the  ordinary  purpose  of  con- 
sumption, proved  a  serious  disadvantage  ;  but  this  objection  hud  no  existence  at  Grimsby, 
where  the  tank  upon  the  tower  furnished  a  separate  source  of  power,  undisturbed  by  any 
interfering  conditions.  Nothing  could  bo  more  effectual  for  its  purpose  than  this  tower ; 
but,  in  the  natural  course  of  improvement,  I  was  subsequently  led  to  the  adoption  of 
another  form  of  artificial  head,  which  possessed  the  advantage  of  being  applicable,  at  a 
comparatively  small  cost,  in  all  situations,  and  of  lessening  the  size  of  the  pipes  and  hy- 
draulic machinery,  by  affording  a  pressure  of  greatly  increased  intensity. 

"The  apparatus  thus  substituted  for  a  water  tower  I  named  '  the  Accumulator,^  from 
the  circumstance  of  its  accumulating  the  power  exerted  by  the  engine  in  charging  it. 
The  accumulator  i.«,  in  fact,  a  reservoir  giving  pressure  by  load  instead  of  by  elevation, 
and  its  use,  like  that  of  every  provision  of  this  kind,  is  to  equalize  the  strain  upon  the 
engine  in  cases  where  the  quantity  of  power  to  be  supplied  is  subject  to  great  and  sudden 
fluctuations. 

"The  construction  of  the  accumulator  is  exhibited  in  fg.  327,  and  needs  but  little 

explanation,      a,  cylinder;  d,  plunger; 
327  c  c,  loaded  weight  case  ;  d,  d,  guides  for 

ditto;  E,  pipe  iVoni  pumping  engine;  f, 
pipe  to  hydraulic  machine.  It  consists 
of  a  large  cast-iron  cylinder,  fitted  with 
a  plunger,  from  which  a  loaded  weight 
case  is  suspended,  to  give  pressure  to  the 
water  injected  by  the  engine.  The  load 
upon  the  plunger  is  usually  such  as  to 
produce  a  pressure  in  the  cylinder  equal 
to  a  column  of  1,500  feet  in  elevation, 
and  the  apparatus  is  made  sufficiently 
capacious  to  contain  the  largest  quantity 
of  water  which  can  be  drawn  from  it  at 
once  by  the  simultaneous  action  of  all 
the  hydraulic  machines  with  which  it  is 
connected.  "Whenever  the  engine  pumps 
more  water  into  the  accumulator  than 
passes  direct  to  the  hydraulic  machines, 
the  loaded  plunger  rises  and  makes  room 
in  the  cylinder  for  the  surplus  ;  but  when, 
on  the  other  hand,  the  supply  from  the 
engine  is  less,  for  the  moment,  than  the 
quantity  required,  the  plunger,  with  its 
load,  descends  and  makes  up  the  defi- 
ciency out  of  store. 

"The  accumulator  also  serves  as  a 
regulator  to  the  engine ;  for  when  the 
loaded  plunger  rises  to  a  certain  height, 
it  begins  to  close  a  throttle-valve  in  the 
steam-pipe,  so  as  gradually  to  reduce  the 
speed  of  the  engine  until  the  descent  of 
the  plunger  again  calls  for  an  increased 
production  of  power. 

"The  introduction  of  the  accumula- 
tor, which  took  place  in  the  year  1851, 
gave  a  great  impulse  to  the  extension  of 
water-pressure  machinery,  which  is  now 
either  already  applied,  or  in  course  of  being  applied,  to  the  purpose  of  cranage  throughout 
all  the  great  dock  establishments  in  London,  as  also  to  a  considerable  extent  in  Liverpool 
and  other  places.  I  have  also  applied  it  extensively  to  railway  purposes,  chiefly  under  the 
direction  of  Mr.  Brunei,  who  has  found  a  multitude  of  cases,  involving  lifting  or  trnctive 
power,  in  which  it  may  be  made  available.  Most  of  these  applications  are  well  exemplified 
at  the  new  station  of  the  Great  Western  Railway  Company  in  London,  where  the  loaduig 
and  unloading  of  trucks,  the  hoisting  into  warehouses,  the  lifting  of  loaded  trucks  from 
one  level  to  another,  the  moving  of  turn-tables,  and  the  hauling  of  trucks  and  traversing 


'^•L! 


i     si 


HYDRAULIC  CRAKES. 


601 


machines,  are  all  performed,  or  about  to  be  so,  by  means  of  hj'draulic  pressure  supplied 
by  one  central  steam-engine  with  connected  accumulators.  Mr.  Rendel  also,  after  hav- 
ing successfully  adopted  the  low-pressure  system  to  the  working  of  the  gates  and  shuttles 
at  Grimsby,  has  since  appUed  the  iiigh-pressure,  or  accumulator  system,  to  the  same  pur- 
poses at  other  new  docks,  and  a  siuiilar  adaptation  is  being  made  by  other  eminent  en- 
gineers at  most  of  the  new  docks  now  in  course  of  construction. 

"  I  have  also  adapted  hydraulic  machinery  to  the  opening  and  closing  of  swing-bridges 
and  draw-bridges  of  large  dimensions ;  and,  in  fact,  there  is  scarcely  any  mechanical 
operation  to  which  human  labor  has  been  hitherto  applied  as  a  mere  moving  power, 
wiiich  may  not  be  efficiently  performed  by  means  of  water-pressure  emanating  from  a 
steam-engine  and  accumidator.  Even  if  hand  labor  be  retained  as  the  source  of  the 
power,  the  intervention  of  an  accumulator  will  in  many  cases  both  economize  labor  and 
increase  despatch.  For  example,  a  pair  of  heavy  dock-gates  requires  the  constant 
attendance  of  a  considerable  number  of  men,  whose  labor  is  only  called  into  action 
occasionally,  viz.,  when  the  gates  are  being  opened  or  closed.  Now,  if  an  accumulator, 
charged  by  hand-pumps,  were  used,  the  labor  employed  would  be  constant,  instead  of 
occasional,  and  the  power  collected  in  the  accumulator  by  the  continuous  process  of 
pumping  would  be  given  out  in  a  concentrated  form,  and  thus  the  ultimate  result  would 
be  effected  with  fewer  hands  and  greater  despatch  than  where  manual  labor  is  directly 
applied. 

"  The  form  of  pumping-engine  which  I  generally  use  for  charging  the  accumulator  is 
represented  in  jig.  323.     It  consists  of  a  horizontal  steam-cylinder,  with  two  force-pumps 

328 


connected  directly  with  the  piston.  These  forcc-putnps  are  supi)!icJ  with  water  from  a 
cistern  over  the  engine-room,  into  which  the  water  discharged  by  the  cranes  is  generally 
brought  back  by  a  return-pipe,  so  that  the  water  is  not  wasted,  but  remains  continuously 
in  use. 

"With  a  pressure  representing  a  column  of  1,500  feet,  the  loss  of  head  by  friction  in 
tiie  pipes  forms  so  small  a  deduction  from  the  entire  column  as  to  be  a  matter  of  no  con- 
sideration, and  consequently  the  distance  at  which  the  engine  may  be  situated  from  the 
points  where  the  hydraulic  machines  may  be  placed,  is  of  little  importance,  except  as  re- 
gards the  cost  of  tiie  pipe.  It  is  advisable,  however,  if  the  pipe  be  very  long,  to  apply 
an  accumulator  at  each  extremity,  so  as  to  charge  the  pipe  from  both  ends. 

"With  regard  to  the  mechanism  of  hydraulic  cranes,  the  arrangement  which  I  first 
adopteil,  and  have  ever  since  adhered  to,  consists  of  one  or  more  hydraulic  presses,  with 
a  set  of  sheaves,  used  in  the  inverted  order  of  blocks  and  pulleys,  for  the  purpose  of 
obtaining  an  extended  motion  in  the  chain  from  a  comparatively  short  stroke  of  the 
piston.  This  construction,  which  characterizes  nearly  all  the  varieties  of  the  hoisting 
and  hauling  machines  to  which  I  have  applied  hydraulic  pressure,  is  exhibited  \nfig.  329, 
which  represents  one  of  these  presses  with  sheaves  attached,  to  multiply  the  motion  four- 
fold. In  cases  where  the  resistance  to  be  overcome  varies  very  considerably,  I  generally 
employ  three  such  cylinders,  with  rams  or  pistons  acting  cither  separately  or  conjointly 
upon  the  same  set  of  multiplying  sheaves,  according  to  the  amount  of  power  required. 

"In  hydraulic  cranes  the  power  is  applied,  not  only  for  Hfting  the  load,  but  also  for 
swinging  the  jib,  which  latter  object  is  effected  by  means  of  a  rack  or  chain  operating 
on  the  base  of  the  movable  part  of  the  crane,  and  connected  either  with  a  cyhnder  and 


602 


HYDRAULIC  CPwANES. 


piston  having  alternate  motion,  like  that  of  a  steam-engine,  or  with  two  presses  applied 
to  produce  the  same  effect  by  alternate  action. 


329 


"The  absence  of  any  sensible  elasticity  in  water  renders  the  motions  resulting  from 
its  pressure  capable  of  the  most  perfect  control,  by  means  of  the  valves  which  regulate 
the  inlet  and  outlet  passages  of  the  machines;  but  this  very  property,  which  gives  so 
much  certainty  of  action,  tends  to  cause  shocks  and  strains  to  the  machinery,  by  resist- 
ing the  momentum  acquired  by  the  moving  parts.  Take,  for  example,  the  case  of  a  hy- 
draulic crane,  swinging  round  with  a  load  suspended  on  the  jib,  the  motion  being  pro- 
duced by  the  water  entering  on  one  side  of  a  piston  and  escaping  from  the  other.  Under 
such  circumstances,  if  the  water-passages  be  suddenly  closed  by  the  regulating  valve,  it 
is  obvious  that  the  piston,  impelled  forward  by  the  momentum  of  the  loaded  jib,  but  met 
by  an  unyielding  body  of  water  deprived  of  outlet,  would  be  brought  to  rest  so  abruptly 
as  to  cause,  in  all  probability,  the  breakage  of  the  machine.  So  also,  in  lowering  a 
heavy  weight  with  considerable  velocity,  if  the  escape-passage  be  too  suddenly  closed,  a 
similar  risk  of  injury  would  arise  from  the  abrupt  stoppage  of  the  weight,  if  a  remedy 
were  not  provided ;  but  these  liabilities  are  effectually  removed  by  applying,  in  connec- 
tion with  the  water-passages  to  the  cylinder,  a  small  clack-valve,  opening  upwards  against 
the  pressure  into  the  supply  pipe,  so  as  to  permit  the  pent-up  water  in  the  cylinder  to 
be  pressed  back  into  the  pipe  whenever  it  becomes  exposed  to  a  compressive  force  ex- 
ceeding the  pressure  on  the  accumulator.  By  this  means  all  jerks  and  concussions  are 
avoided,  and  a  perfect  control  over  the  movement  of  the  machine  is  combined  with  great 
softness  of  action. 

"  With  regard  to  the  kind  of  valves  used  for  water-pressure  machines,  I  find  that 
either  lift-valves  or  slide-valves  may  be  effectually  applied,  and  kept  tight  under  heavy 
pressures,  provided  that  sand  be  excluded  from  the  water,  and  the  valves  be  made  of 
proper  material. 

"In  cases  where  a  more  prolonged  movement  is  required  than  multiplying  sheaves 
will  conveniently  afford,  I  employ  rotative  machines  of  various  constructions.  For 
heavy  pressures,  such  as  an  accumulator  affords,  an  arrangement  consisting  of  three 
plungers,  connected  with  a  triple  crank,  and  bearing  a  general  resemblance  to  a  three- 
throw  plunger  pump,  is  well  adapted  for  tlie  purpose.  The  admission  and  exhaust  valves 
are  mitred  spiruilcs,  pressed  down  by  weights  and  levers,  and  lifted  in  proper  rotation 
by  cams  fixed  for  that  purpose  upon  a  separate  shaft ;  and  these  valves  ;ire  associated 
with  relief-clacks,  to  obviate  the  concussion  which  would  otherwise  be  liable  to  take  place 
at  the  turn  of  each  stroke. 

"  The  liability  of  water-pressure  machinery  to  be  deranged  by  frost  has  often  been 
adduced  as  an  objection  to  its  use ;  and  upon  this  point  I  may  observe — first,  that  I  have 
never  experienced  any  interference  from  this  cause  when  the  machines  were  placed,  as 
they  generally  are,  beneath  the  surface  of  the  ground,  or  within  a  building ;  and  second- 
ly, that  when  they  are  unavoidably  exposed,  all  risk  may  be  prevented  by  letting  out  the 
water  in  frosty  weather  whenever  the  machines  cease  working. 

"When  the  moving  power  consists  of  a  natural  column  of  water,  the  pressure  rarely 
exceeds  250  or  300  feet,  and  in  such  cases  I  have  employed  for  rotative  action  a  pair  of 
cylinders  and  pistons,  with  slide-valves,  resembling  in  some  degree  those  of  a  high- pres- 
sure engine,  but  having  relief  valves,  to  prevent  shock  at  the  turn  of  the  stroke.  Fie;.  330 
shows  a  slide-valve  adapted  for  the  turning  apparatus  of  a  crane,  but  the  relief-clacks  of 


HYDRIODIO  ACID. 


603 


which  are  equally  applicable  to  a  water-pressure   engine  of  the  construction  in  question. 

Two  of  tlicse  clacks  open  against  the  pressure  in  the  supply  pipe,  so  as  to  afford  an 

escape  for  the  water,  which  would  otherwise  be  shut  up 

in  the  cylinder  when  the  exhaust  port  closes,  and  the 

other  two  communicate  with  the  discharge  pipe,  so  as 

to  draw  ia  a  portion  of  waste  water  to  fill  up  the  small 

vacancy  which  would  otherw!  e  be  left  in  the  cylinder 

on  the  closing  of  the  admission  port,     a,  supply  pipe; 

B,  exhaust  pipe ;  c  c,  pipes  to  cylinder ;  d  d,  clacks 

opening  against  piessure ;  e  e,   clacks  opening  from 

exhaust.      About  four   years  ago   I  constructed  four 

hydraulic  engines  upon  this  principle  at  Mr.  Beaumont's 

lead  mines  in  Northumberland,  at  the  instance  of  Mr. 

Sopwith,  Mr.  Beaumont's  well-known  agent,  and  two 

more  have    recently  been    added  at  the  same    place. 

They  are  used  for  crushing  ore,  for  hoisting  materials 

from  the  mines,  for  pumping  water,  and  for  driving  a 

circular  saw  and  other  machinery.     See  Water-pkes- 

SURE  Machinery,  applied  to  mines. 

"  If  in  progress  of  time  railways  should  be  generally 
extended  into  mountainous  districts,  so  as  to  render 
them  accessible  for  manufacturing  purposes,  the  rapid 
streams  which  abound  in  such  localities  will  probably 
become  valuable  sources  of  motive  power,  and  a  wider 
field  may  then  be  afforded  for  the  application  of  water-pressure  engines  to  natural  falls. 

"  The  object,  however,  which  I  have  cliiefly  had  in  view  since  I  first  gave  attention 
to  this  subject,  has  been  to  provide  in  substitution  of  manual  labor,  a  method  of  working 
a  multiplicity  of  machines,  intermittent  in  their  action,  and  extending  over  a  large  area, 
by  means  of  transmitted  power  produced  by  a  steam-engine  and  accumulated  at  one 
central  point.  The  common  mode  of  communicating  power  by  shafting  could  only  be 
applied  in  cases  where  the  maciiines  were  collected  within  a  small  compass,  and  where 
the  accumulation  of  power  necessary  to  meet  varying  resistance  did  not  exceed  that 
which  a  fly-wheel  would  afford.  Compressed  or  exhausted  air  was  almost  equally  inappli- 
cable to  the  purpo5es  I  contemplated,  in  consequence  of  the  many  objections  which  its 
elasticity  involves,  as  welt  as  the  liability  to  leakage,  which,  in  an  extended  system  of 
pipes  and  machines,  requiring  a  multitude  of  joints,  valves,  and  fitting  surfaces,  would 
form  an  insurmountable  difficulty.  But  the  use  of  water  as  a  medium  of  transmission  is 
free  from  all  these  objections,  and  its  fitness  for  the  purpose  intended  is  now  thoroughly 
established  by  the  results  which  have  been  obtained." 

HYDRIODIO  ACID  (Acide  H;/driodigue,  Fr. ;  lli/driodmnre,  Germ.)  is  an  acid  formed 
by  the  combination  of  127  parts  of  iodine  with  1  part  of  hydrogen  by  weight,  and  by 
measure  cijual  volumes  of  iodine  vapor  and  hydrogen  combined  witliout  condensation. 
It  is  obtained  pure  and  in  tlie  gaseous  state  by  introducing  into  a  glass  tube,  closed  at 
one  end,  a  little  iodine,  then  a  small  quantity  of  roughly-powdered  glass  n.oistened  with 
water,  upon  this  a  few  small  fragments  of  phosphorus,  and  lastly  more  glass;  this  order, 
iodine,  glass,  phosphorus,  glass,  is  repeateil  until  the  tube  is  two-thirds  filled.  A  cork 
and  narrow  bent  tube  are  then  fitted  and  gentle  heat  applied,  when  the  hydriodic  acid  is 
liberated,  and  may  be  collected  in  dry  bottles  by  the  displacement  of  air.  Anotlier  pro- 
cess is  to  place  in  a  small  retort  10  parts  of  iodide  of  potassium  with  5  of  water,  add  20 
parts  of  iodine,  then  drop  in  cautiously  1  p;irt  of  phosphorus  cut  into  small  pieces,  and 
apply  a  gentle  heat;  hydriodic  acid  will  be  formed  abundantly,  and  may  be  coilected'as 
before  stated.     The  following  equation  expresses  the  reaction: 

2KI+  5I  +  P  +  SH0  yield  2IvO,nO,PO'-h'7HI. 
Hydriodic  acid  greatly  resembles  hydrochloric  acid ;  it  is  colorless,  and  highly  acid ;  it 
fumes  in  the  air,  and  is  very  soluble  in  water.     Its  density  is  4-4,  and  under  strong  pres- 
sure condenses  to  a  yellowish  liquid,  which  solidifies  at  00'^  Fahr. 

Hydriodic  acid  in  solution  is  much  more  easily  prepared,  by  suspending  iodine  in 
water,  and  passing  a  stream  of  washed  hydrosulphuric  acid  tiirough  it  until  the  color 
disappears ;  it  is  then  heated  to  expel  the  hydrosulphuric  acid,  then  allowed  to  rest, 
wlien  it  may  be  decanted  from  the  prcei()itate  of  sulphur.  The  reaction  consists  simply 
in  the  displacement  of  the  sulphur  by  the  iodine,  IlS-f-I  =rHI-fS. 

This  li((uid  may  be  evaporated  until  it  accjuires  a  (hmsity  of  TT,  when  it  consists  of 
in +  11  no.  It  then  distils  at  262"  Fahr.  witliout  decomposition.  Tiie  solution  cannot 
be  long  kept,  being  decomposed  by  the  oxygen  of  tiie  air  with  the  liberation  of  iodine, 
which  imparts  a  dark  color  to  it.  Chlorine  decomposes  it  instantly,  with  liberation  of 
the  iodine. 

The  solution  of  hydriodic  acid  and  of  the  iodides  possesses  the  power  of  dissolving  a 
considerabli!  quantity  of  iodine,  formini;  a  <lark-  solulion. — II.  K.  15. 


604  HYDROOYANIO  ACID. 

HYDKOCYANIC  ACID.  Syn.  Cyanhydric  acid,  Prussic  acid,  C'XH.  This  highly 
important  acid  is  regarded  by  all  chemists  as  being  formed  on  the  exact  type  of  the  ordi- 
nary inorganic  hydracids,  such  as  the  hydrochloric  or  hydriodic.  The  compound  radical 
analogous  to  chlorine,  which  is  contained  in  it,  has  received  •the  name  of  cyanogen,  and 
possesses  the  formula  CN.  That  this  body  is  precisely  analogous  in  its  relations  to  the 
simple  salt  radicals  is  rendered  certain  by  numerous  facts.  It  combines  directly  with 
metals  to  form  compounds  ;  it  possesses  the  same  vapor  volume,  and  unites  with  hydrogen  to 
form  a  hydracid,  which  in  its  turn  decomposes  the  metallic  oxides  with  formation  of  water. 
Thus  we  have,  with  metallic  oxides  and  hydrochloric  acid,  (M  standing  for  a  metal,) 
MO-l- HC1  =  MC1  +  II0,  and  with  hydrocyanic  and  metallic  oxides,  (Cy  standing  for  cy- 
anogen), MO +IICy=::MCy+ HO.  Two  volumes  of  chlorine  and  two  of  hydrogen  yield 
four  volumes  of  hydrochloric  acid  gas,  and  two  volumes  of  cyanogen  with  two  of  hydrogen 
yield  four  volumes  of  hydrocyanic  acid.  The  density  of  the  vapor  of  hydrocyanic  acid  is 
consequently  0-9476.  Tiie  theoretical  number  being  0'9342.  Its  density  in  the  fluid  state 
is  0'G967  at  a  temperature  of  64-4'.     It  boils  at  SO"  F.  at  ordinary  pressures. 

Hydrocyanic  acid  is  never  prepared  in  the  anhydrous  state,  except  as  a  curio.sity,  or  for 
the  purpose  of  scientific  investigation.  In  fact  it  cannot  be  long  preserved  of  great 
strength  ;  a  somewhat  complex  decomposition  invariably  taking  place  in  it,  with  production 
of  brown  adhesive  matters  containing  cyanide  of  ammonium,  and  also  a  substance  by  some 
considered  to  be  an  acid,  and  known  as  the  azulmic.  Paracyanogen  is  probably  formed  at 
the  same  time.  The  constitution  of  azulmic  acid  is  by  no  means  well  known,  and  even  its 
very  existence,  as  a  definite  chemical  substance,  is  doubtful.  It  is  singular  that  the  presence 
of  a  mineral  acid  greatly  retards  the  decomposition  of  piussic  acid,  especially  if  it  be  dilute ; 
the  pharmacopa>ian  acid  consequently  may  be  preserved  of  uniform  strength,  in  well  filled 
and  closely  stoppered  bottles,  for  almost  any  length  of  time.  The  deadly  nature  of  prussic 
acid  unhappily  causes  it  to  be  only  too  frequently  resorted  to  by  the  despairing  or  the  mur- 
derer. Fortunately,  however,  in  spite  of  its  volatility,  the  chemist  possesses  excellent  means 
for  its  detection. 

Preparation. — 1.  Hydrated  acid.  As  prussic  acid  is  largely  employed  in  medicine,  but 
in  a  very  dilute  form,  it  is  usual  to  prepare  it  and  dilute  until  of  the  proper  degree  of 
strength.  The  following  process  for  preparing  it  will  be  found  to  give  a  satisfactory  re- 
sult, and,  moreover,  it  may  be  performed  on  any  quantity  of  materials.  The  apparatus 
for  the  purpose  will  vary  with  the  scale  on  which  the  experiment  is  to  be  made.  If  on 
a  few  ounces,  glass  retorts  and  flasks  answer  well,  if  good  condeq^ation  is  insured  by  means 
of  a  Liebig's  condenser  well  supplied  with  very  cold  water.  If  a  large  quantity  of  prussic 
aoid  is  to  be  made,  such  as  several  gallons,  the  apparatus  should  consist  of  a  stoneware  still, 
with  head  adjusted  by  grinding.  The  head  should  be  capable  of  adjustment  with  a  stone- 
ware adapter  to  a  worm  of  the  same  material  enclosed  in  a  tub  of  water.  The  joints  are 
to  be  luted  with  a  mixture  of  one  handful  of  almond  meal  and  five  handfuls  of  linseed 
meal,  worked  with  water  to  the  consistence  of  putty.  A  solution  of  rough  chloride  of 
calcium  in  water  is  to  be  made  and  placed  in  a  large  iron  pot,  with  a  cover  so  contrived  as 
to  permit  the  still  to  drop  in  up  to  the  flange.  10  parts  of  yellow  prussiate  of  potash  are 
then  to  be  bruised  in  a  mortar  and  mixed  with  dilute  sulphuric  acid  prepared  by  adding  6 
parts  of  sulphuric  acid  (density  1'850)  to  42  of  water.  The  head  being  luted  on,  a  fire  is 
to  be  kindled  in  the  furnace  under  the  iron  pot,  and  the  chloride  of  calcium  bath  is  to  be 
kept  boiling  constantly  until  3(j  parts  of  acid  have  distilled  over.  The  beak  of  the  .-^till 
should  be  placed  in  the  funnel  which  conducts  the  acid  to  the  Winchester  quart  bottles 
which  are  to  contain  the  product,  and  a  piece  of  wet  bladder  is  to  be  stretched  over  the 
funnel  to  prevent  evaporation  of  the  acid  into  the  laboratory.  The  worm  used  lor  the  pur- 
pose must  be  ascertained  to  be  perfectly  clean,  and,  if  prussic  acid  is  to  be  frequently 
made,  should  be  kept  specially  for  that  operation.  To  each  Winchester  quart  of  the  acid 
distilling  over,  one  drop  of  sulphuric  acid  may  be  added  to  insure  its  keeping.  But 
the  acid  thus  prepared  generally  keeps  for  a  long  time  even  without  this  precaution, 
owing  probably  to  small  traces  of  the  sulphuric  acid  being  carried  over  during  the  dis- 
tillation. 

It  is  quite  impossible  to  conduct  the  operation  so  as  to  yield  a  product  of  unifoim 
strength ;  it  is  absolutely  necessary,  therefore,  to  determine  the  percentage  of  real  hydro- 
cyanic acid,  and  dilute  it  to  the  required  degree.  It  fortunately  happens  that  1  grain  of 
hydrocyanic  acid  yields  almost  exactly  5  grains  of  cyanide  of  silver  ;  for  one  eciuivalent  of 
acid  =  27  produces  1  equivalent  of  cyanide  of  silver  =  1!>4 ;  so  that  27  :  134  : :  1  :  4'9fi. 
The  acid  produced  will  have,  probably,  to  be  reduced  to  one  of  two  standards  ;  namely,  the 
so-called  Scheele'a  strength,  containing  5  per  cent,  of  acid,  or  the  P.L.,  containing  2  per 
cent.  ;  100  grains  of  the  former  should,  consequently,  yield  25  grains,  and  Itio  of  the  P.L. 
10  grains  of  cyanide  of  silver.     In  either  case  the  calculation  becomes  obvious. 

2.  The  anhydrous  acid.  Several  processes  for  conducting  this  dangerous  operation  are 
known  ;  the  following  is,  perhaps,  the  most  generally  convenient.  A  large  glass  retort  is 
80  arranged  that  its  neck  is  directed  upwards  at  an  angle  of  about  45° ;  a  cork  fitted  to  the 


HYPOCHLOROUS  ACID.  605 

aperture  in  the  neck  connects  a  glass  tube  with  a  bottle  containing  a  little  chloride  of  cal- 
cium. From  the  latter  vessel  another  tube  proceeds  to  a  U  tube  containing  fragments  of 
chloride  of  calcium,  and  from  the  latter  a  third,  conducting  the  dehydrated  vapor  of  prus- 
sic  acid  to  an  upright  glass  tube  contained  in  a  mixture  of  ice  and  salt.  Into  the  retort  is 
placed  a  mixture  of  10  parts  of  yellow  prussiate  of  potash,  7  of  oil  of  vitriol,  and  14  of 
water.  The  retort  is  to  be  heated  with  a  ciuucoal  fire,  and  the  temperature  of  the  bottle 
and  U  tube,  containing  the  chloride  of  calcium,  is  not  to  be  allowed  to  fall  below  90%  in 
order  to  prevent  condensation  of  the  anhydrous  prussie  acid  taking  place  anywhere  except 
in  the  tube  contained  in  the  freezing  mixture.  The  vapor  of  anhydrous  prussic  acid  is 
so  dangerous  that  the  greatest  precaution  must  be  taken  to  prevent  inhaling  the  smallest 
portion. 

Detection  of  prussic  acid. — When  prussic  acid  exists  in  moderate  quantity  in  a  solution 
it  may  be  detected  by  first  adding  a  few  drops  of  potash,  then  a  mixture  of  protosulphate 
and  persulphate  of  iron,  and  finally  a  little  hydrochloric  acid  ;  a  bright  blue  precipitate  in- 
dicates the  presence  of  the  acid.  A  much  more  delicate  test,  and  one  that  is  applicable 
when,  from  the  dilution  of  the  solution,  the  salts  of  iron  are  no  longer  capable  of  acting, 
is  by  the  conversion  of  the  prussic  acid  into  sulphocyanide  of  ammonium.  For  this  pur- 
pose the  prussic  acid  is  to  be  warmed  on  a  watch-glass  with  a  drop  of  sulphide  of  ammo- 
nium, until  the  solution  has  become  colorless.  The  addition  of  a  trace  of  a  solution  of  a 
persalt  of  iron  will  show,  by  the  formation  of  a  blood-red  color,  the  presence  of  the  acid 
sought.  A  very  neat  mode  of  applying  this  test  is  to  place  one  drop  of  sulphide  of  ammo- 
nium on  a  watch-glass  inverted  over  another  containing  the  suspected  fluid.  On  leaving 
the  apparatus  in  a  warm  place,  arranged  in  this  manner,  for  a  short  time,  the  upper  glass 
will  be  found  to  contain  sulphocjiiuide  of  ammonium,  which,  after  drying,  will  be  in  a  state 
well  adapted  for  showing  the  reaction  with  a  persalt  of  iron. — C.  G.  W. 

HYDRODYNAMICS.  The  mechanical  science  which  treats  of  the  motion  of  fluids. 
This  science  has,  of  course,  most  important  bearings  on  the  pumping-engines,  water-wheels, 
&c.,  employed  to  facilitate  the  operation  of  the  miner.  It  is  not,  however,  possible  to 
embrace  this,  which  belongs  to  mechanical  engineering,  in  this  work. 

HYDRO-EXTRACTOR.  A  name  sometimes  given  to  the  machine  employed  for  ex- 
pelling the  water  from  woven  goods. 

HYDROFLUORIC  ACID.  It  was  observed  by  Scwankhardt,  in  1670,  that  fluor  spar 
and  oil  of  vitriol  would  eat  into  glass.  Scheele,  in  1771,  determined  that  this  peculiar 
property  was  due  to  the  liberation  of  an  acid  from  the  fluor  spar. 

Hydrofluoric  acid  is  best  obtained  by  placing  finely  powdered  fluor  spar  in  a  leaden 
retort,  and  twice  its  weight  of  highly  concentrated  oil  of  vitriol.  By  a  gentle  heat 
the  gas  is  distilled  over,  which  must  be  collected  in  a  leaden  tube,  in  which,  by  means 
of  a  freezing  mixture,  it  may  be  condensed  into  a  liquid.  If  a  solution  of  this  acid  in 
water  is  required,  the  extremity  of  the  tube  from  the  retort  is  carried  into  a  vessel  of 
water. 

Hydrofluoric  acid  attacks  glass  with  great  readiness,  by  acting  on  its  silica. 

Glass  upon  which  any  design  is  to  be  etched,  is  covered  with  an  etching  wax,  and  the 
design  made  in  the  usual  manner ;  this  is  placed  over  a  leaden  vessel,  in  which  is  a  mixture 
of  fluor  spar  and  oil  of  vitriol ;  a  gentle  heat  being  applied,  hydrofluoric  acid  escapes,  and 
immediately  attacks  the  glass. 

HYDROPHANE.  A  variety  of  opal  which  readily  imbibes  water,  and  when  immersed 
it  becomes  transparent,  though  opaque  when  dry.  It  is  found  in  Hungary,  and  in  Ireland, 
near  the  Giant's  Causeway,  and  at  Crosreagh,  Ballywillin. 

HYDROSTATICS.  The  science  which  treats  of  the  equilibrium  of  fluids,  and  of  the 
pressure  exerted  by  them. 

In  the  engineering  arrangements  by  which  water  is  supplied  to  towns,  hydrostatics  be- 
comes of  the  utmost  importance.  The  highest  possible  level  is  obtained  for  the  reservoir ; 
and  from  this  a  series  of  pipes  is  arranged  through  all  the  streets  and  houses.  Tlio  tenden- 
cy of  the  water  is  to  rise  to  its  original  level,  and  hence  all  the  pipes  are  filled  witli  water, 
and  in  all  such  as  are  below  the  level  of  the  water  in  the  reservoir  a  pressure  upwai-ds  is 
exerted  equal  to  the  height  of  the  reservoir  above  that  point ;  and  if  a  hole  is  pierced  in  the 
)»ipe,  the  water  jets  out  with  a  force  equal  to  this  pressure.  In  the  highest  houses,  the 
water  perha})s  only  finds  its  level,  and  flows  out  without  pressure  quickly.  See  Water 
PuEssuRE  Machinery  for  Mixes  ;  Hydraulic  Cranes. 

HYPOCHLORIC  ACID.  C10\  Eq.  07-5.  When  finely  powdered  chlorate  of  potash  is 
gradually  mixed  into  a  paste  with  strong  sulphui  ic  acid,  and  heated  in  a  bath  of  alcohol  and 
water,  a  yellow  gas  is  disengaged  which  is  this  hypochloric  acid,  or  the  ])croxide  of  ililorine. 
Although  of  much  interest  as  a  chemical  compound,  it  has  no  use  in  the  arts.  Sec  Ure^s 
Chemical  Dictionan/. 

HYPOCHLOROUS  ACID.  ClOjEq.  43-5.  This  acid  is  best  obtained  by  diffusing  red 
oxide  of  mercury  finely  divided  through  twelve  times  its  weight  of  water,  wliich  is  introduced 
into  a  bottle  containing  chlorine,  and  agitated  until  the  g;is  is  absorbed.     An  oxychloride  of 


606  HYPOSULPHITES. 

mercury  is  formed,  which  is  removed  by  subsidence.  The  weak  fluid  obtained  is  put  into  a 
flask,  and  heated  in  a  water  bath,  when  the  evolved  gas  is  collected  in  a  smaller  portion  of 
water,  which  becomes  a  pure  solution  of  hypochlorous  acid. 

HYPOSULPHITES.  Saline  compounds  formed  by  the  union  of  hyposulphurous  acid 
with  bases. 

Hyposuljihate  of  Soda. — The  salts  of  thehyposulphuricacid  are  obtained  from  the  hypo- 
sulphate  of  manganese,  which  is  itself  thus  prepared :  finely  divided  binoxide  of  manganese 
is  suspended  in  water,  artificially  cooled,  and  a  stream  of  sulphurous  acid  passed  through 
it.  The  binoxide  gives  up  half  its  oxygen,  becoming  protoxide,  which  unites  with  the 
hyposulphuric  acid  which  is  formed,  producing  the  soluble  hyposulphate  of  manganese, 
which  is  separated  from  the  excess  of  binoxide  by  filtration. 

The  following  equation  rej^resents  the  reaction  : — 

MnO'  +  2S0*  =  MnO,S'0^ 

If  the  temperature  were  allowed  to  rise,  sulphuric  acid  would  be  formed,  and  not  hypo- 
sulphuric  : — 

MnO=  +  SO''  =  MnO,SO^ 

The  hyposulphuric  acid,  unlike  the  hyposulphurous  acid,  may  be  obtained  in  the  free 
state,  and  its  solution  permits  even  of  being  evaporated  in  vacuo,  until  it  acquires  the 
density  of  1-347  ;  but  if  carried  further,  it  is  decomposed  into  sulphuric  and  sulphurous 
acids. 

The  acid  is  obtained  in  the  free  state  by  adding  baryta  water  to  the  hyposulphate  of 
manganese ;  the  soluble  hyposulphate  of  baryta,  filtered  from  the  oxide  of  manganese,  and 
precipitated  exactly  by  the  cautious  addition  of  sulphuric  acid,  and  filtered  from  the  pre- 
cipitate of  sulphate  of  baryta,  yields  the  pure  solution  of  the  acid,  which  may  be  evaporated 
in  vacuo,  as  above  stated. 

It  has  no  odor,  but  a  very  sour  taste. 

The  hyposulphate  of  soda  may  be  made  directly  from  the  manganese  salt  or  from  the 
free  acid. 

.   All  the  hyposulphates  are  soluble ;  they  have  not  as  yet  met  with  any  commercial  appli- 
cation. 

Hi/posulphite  of  Soda. — This  salt,  now  so  extensively  used  for  photographic  purposes, 
was  first  introduced  by  Sir  J.  Herschel.  It  may  easily  be  prepared  by  the  following  pro- 
cess, viz.,  by  transmitting  through  a  solution  of  sulphide  of  sodium  (prepared  by  fusing 
together  in  a  covered  crucible  equal  weights  of  carbonate  of  soda  and  flowers  of  sulphur) 
a  stream  of  sulphurous  acid  until  it  ceases  to  be  absorbed  ;  the  liquid  is  then  filtered  and 
evaporated,  when  the  hvposulphite  of  soda  (XaO,S"0-  +  5110)  crystallizes  out. 

Another  and  perhaps  better  process  consists  in  digesting  a  solution  of  sulphite  of  soda 
on  flowers  of  sulphur.  The  sulphur  gradually  dissolves,  forming  a  colorless  solution,  which 
yields  on  evaporation  crystals  of  hyposulphite  of  soda  ;  the  reaction  being  shown  by  the 
following  equation : — 

XaO,SO*  +  S  =  NaO,S'0\ 

The  baryta  salt  may  be  obtained  in  small  brilliant  crystals,  by  mixing  dilute  solutions 
of  chloride  of  barium  and  hyposulphite  of  soda. 

The  hyposulphurous  acid  is  incapable  of  existing  in  the  free  state,  for  almost  imme- 
diately on  the  addition  of  an  acid  to  the  solution  of  its  salts,  it  is  decomposed  into  sul- 
phurous acid,  with  liberation  of  sulphur.     (S"0'  =  SO^  +  S.) 

The  soluble  hyposulphites  have  the  power,  in  a  marked  degree,  of  dissolving  certain 
salts  of  silver,  as  the  chloride,  iodide,  &c.,  which  are  insoluble  in  water;  forming  wuth 
them  soluble  salts,  whose  solutions  possess  an  intensely  sweet  taste,  although  the  solutions 
of  the  hyposulphites  alone  possess  a  disagreeable  bitter  taste. 

From  the  above  reaction  arises  the  principal  value  of  the  hyposulphite  of  soda,  which 
is  used  by  the  photographer  to  dissolve  off  from  the  photograph,  after  the  action  of  the 
light  on  it,  all  the  undecomposed  silver  salt,  thus  preventing  the  further  action  of  the  light 
on  the  picture. 

A  double  hyposulphite  of  soda  and  gold  is  used  for  gilding  the  daguerreotype  plate,  and 
for  coloring  the  positive  proof  obtained  in  photographic  printing.  This  double  salt  may  be 
obtained  in  a  state  of  purity,  by  mixing  concentrated  solutions  of  1  part  of  chloride  of 
gold,  and  3  parts  of  hyposulphite  of  soda  ;  by  the  addition  of  alcohol  it  is  precipitated ; 
the  precipitate  must  be  redissolved  in  a  small  quantity  of  water,  and  again  precipitated  by 
alcohol.     Its  formation  is  explained  by  the  following  equation  : — 

8(NaO,S'0')  +  AuCP  =  2(Xa0,S^0=')  +  Au0,S'0-,.3(Na0,S^0^)  -f    3XaCl. 


Tetrathionate  of      IlyposulphitR  of  soda  and  Chlor. 

soda.  gold.  of  sodium. 

H.  K.  B. 


INDIGO. 


607 


ILLUMINATION.  The  numerical  estimation  of  the  degrees  of  intensity  of  light  con- 
stitutes that  branch  of  optics  which  is  termed  Photometry. 

Bunseri's  photometer  consists  of  a  sheet  of  cream-colored  letter  paper,  rendered  trans- 
parent over  a  portion  of  the  surface  by  a  mixture  of  spermaceti  and  rectified  naphtha, 
which  is  solid  at  common  temperatures,  but  becomes  liquid  on  the  application  of  a  very 
gentle  heat.  The  mixture  is  liquefied  and  painted  over  the  paper  with  a  brush,  leaving  a 
round  disc  of  the  size  of  half  a  crown  in  the  centre  uncovered.  When  a  light  is  placed  on 
one  side  of  the  paper  a  dark  spot  is  observed  on  the  uncovered  portion.  When  another 
light  is  placed  on  the  other  side  of  the  paper,  the  spot  is  still  distinctly  visible,  if  the  dis- 
ta°ice  of  the  light  is  such  that  the  reflected  portion  from  the  paper  be  either  of  greater  or 
of  less  intensity  than  that'  transmitted.  When  the  paper  is  so  situated  between  the  two 
flames  that  the  transmitted  and  reflected  light  are  of  the  same  intensity,  the  uncovered  spot 
is  no  longer  visible. 

It  is  possible  onlv,  to  compare  one  light  with  another ;  there  is  not  any  arrangement  by 
which  we  are  enabled  to  express  absolutely  the  illuminating  power.  Upon  the  principle  of 
comparison,  and  comparison  only,  the  following  tables  have  been  constructed  by  the  rela- 
tive experimentalists.  The  following  comparative  view  of  wax  and  stoarine  candles  manu- 
factured in  Berlin,  which  have  been  deduced  from  the  observations  of  Schubarth,  is  of 
much  value. 


Eelative 

Consumption 

Relative 

Kind  of  candles,  and  whence  obtained. 

intensity  of 

in  one  hour, 

illuminating 

light. 

in  grammes. 

power. 

i  4's 

103-5 

7-877 

85-20 

Common  wax  candles,  of  Tann- 

A  6  s 

91-0 

7-176 

83-20 

hanser   

8's 

100-0 

6-562 

100-0 

(4's 

132-7 

9-398 

92-66 

Wax  candles,  of  Walker   - 

]6\s 

120-3 

8-082 

97-69 

J  8's 

1131 

7-132 

104-1 

(  4's 

117-4 

9-4-27 

81-74 

Stearine  candles,  of  Motard 

\  6's 

111-8 

9-383 

78-23 

(8's 

121-0 

7-877 

100-7 

\  '^'^ 

139-5 

10-63 

86-11 

Stearine  candles,  of  Magnet  and 

•J  ti's 

132-7 

9-398 

92-66 

Oehmichen     -         -         -         - 

(  8's 

125-0 

8-506 

96-54 

Stearine  candles,  from  the  same 

\  G's 
\  8's 

116-1 

8-871 

85-86 

makers 

146-0 

8-886 

108-0 

(4's 

1-24 -5 

9-880 

82-67 

Candles  made  from  palm  oil 

)6's 

115-3 

9-178 

82-56 

(8's 

167-5 

8-813 

113-70 

These  results  show  us  that  the  mean  illuminating  power  of  wax  and  stearine  candles  is 
nearly  the  same. 

INDIGO.  We  are  indebted  to  Dr.  Roxburgh,  for  a  description  of  the  method  em- 
ployed for  manufacturing  indigo  from  the  Nerium  tinctorinni  or  Wrightia  tinctorio. 
(Vide  Transactions  of  the  Society  of  Arts,  vol.  xxviii.)  This  plant,  which  attains  the  size 
of  a  small  tree,  is  found  on  the  lower  regions  of  the  mountainous  tract  near  Rajamundry, 
and  also  on  hills  in  tlie  neighborhood  of  Salem  and  Pondicherry,  and  grows  in  a  sterile 
as  well  as  rich  soil.  The  leaves  begin  to  appear  in  March  and  April,  and  at  the  end  of 
April  have  attained  their  full  size,  when  they  are  ready  for  gathering.  At  the  end  of 
August  they  begin  to  assume  a  yellowish  rusty  color,  and  soon  fill  olf.  The  leaves  yield 
no  indigo  until  the  plant  is  several  years  old,  but  the  best  leaves  for  making  indigo  are 
obtained  from  low  bushy  plants.  They  improve  when  kept  for  a  day  or  two,  but  when 
they  begin  to  wither,  they  yield  but  a  small  portion  of  very  bad  indigo,  and  when  quite 
dry  only  a  dirty  brown  fecula.  In  this  they  differ  from  leaves  of  the  common  indigo 
plant,  which  may  be  dried  before  extraction  without  loss  of  color.  They  al?o  differ  from 
the  latter  in  not  yielding  their  color  to  cold  water.  With  cold  water  only  a  hard,  black, 
flinty  substance  is  obtained,  not  blue  indigo.  It  is  therefore  necessary  to  employ  hot 
water,  which  extracts  the  color  very  readily.  The  leaves,  having  been  collected,  are  on 
the  ensuing  day  thrown  into  copper  scalding-vessels,  which  are  then  filled  with  cold  water 
to  within  2  or  3  inches  of  the  top.  Hard  water  containing  a  large  (piantity  of  bicarbon- 
ate of  lime  is  belter  adapted  for  tlip*  purpose  than  rain  water.  The  fire  is  then  lighted 
and  maintained  rather  briskly  until  the  liquor  acquires  a  deej)  green  color.  The  leaves 
tlicn  begin  to  assume  a  yellowish  color,  the  heat  of  the  li(iuor  being  about  150°  to  100° 


608  INDIGO. 

Fahr.  The  fire  is  then  removed  and  the  liquor  run  off  into  the  beating-vat.  Here  it  is 
agitated  from  5  to  20  minutes.  It  is  then  mixed  with  about  Vvo  to  Vioo  part  of  lime 
water,  which  pi'oduces  a  speedy  granulation.  After  the  indigo  has  subsided  the  super- 
natant liquid  appears  of  a  clear  Madeira  wine  color.  The  ciuantity  of  indigo  obtained 
amounts  to  1  lb.  from  250  lbs.  of  green  leaves;  but  it  varies  according  to  the  season  and 
the  state  of  the  weather.  In  August  and  September,  the  produce  is  only  one-half  or 
two-thirds  of  what  it  is  in  May  and  June,  and  even  that  is  diminished  if  the  weather  is 
wet,  or  the  leaves  are  treated  immediately  after  being  gathered.  The  scalding  requires 
about  three  hours,  and  the  agitation  and  precipitation  the  same  time.  The  indigo  is  im- 
proved by  treating  it  with  a  little  sulphuric  acid.  The  only  fault  it  has  is,  that  it  breaks 
into  small  pieces,  unless  it  has  been  dried  slowly  in  the  shade,  protected  from  tlie  sun. 
In  the  southern  provinces  of  China  a  species  of  Indigofcra  is  extensively  cultivated 
for  the  sake  of  the  dye  which  it  affords.  In  the  northern  provinces  two  other  plants  are 
employed  by  the  inhabitants  for  the  same  purpose.  Mr.  Fortune,  the  well-known  Chinese 
traveller,  to  whom  we  owe  the  description  of  these  plants  and  of  the  process  of  manu- 
facturing indigo  from  them,  states  that  one  of  them  is  grown  in  the  neighborhood  of 
Shangliac,  and  he  has  given  it  the  name  of  hatis  imlir/oticd.  The  other,  which  is  a  species 
oi  Jusiicia,  is  largely  cultivated  in  the  hilly  country  near  Ningpo,  or  rather  in  the  valleys 
among  the  hills.  It  seems  to  be  easily  cultivated ;  it  grows  most  luxuriantly,  and  is  no 
doubt  very  productive.  Having  evidently  been  introduced  from  a  more  southern  latitude, 
it  is  not  hardy  in  the  province  of  Chekiang  any  more  than  cotton  is  about  Shanghae  ;  but 
nevertheless  it  succeeds  admirably  as  a  summer  crop.  It  is  planted  at  the  end  of  April 
or  beginning  of  May,  after  the  spring  frosts  are  over,  and  it  is  cleared  from  the  ground 
in  October.  During  this  period  it  attains  a  height  of  a  foot  or  a  foot  and  a  half,  be- 
comes very  bushy,  and  is  densely  covered  with  large  green  leaves.  It  is  cut  before  any 
flowers  are  formed.  The  plants  are  grown,  not  from  seed  but  from  cuttings.  These  cut- 
tings consist  simply  of  a  portion  of  the  stems  of  the  previous  year,  which,  after  being 
stripped  of  their  leaves,  arc  tied  into  bundles,  each  containing  upwards  of  1,000,  and  kept 
during  the  winter  in  a  dry  shed  or  outhouse,  where,  after  being  firmly  packed  together, 
they  are  banked  round  with  dry  loam,  and  covered  with  straw  or  litter  so  as  to  protect 
them  from  the  frost.  During  the  winter  months  the  cuttings  remain  green  and  plump, 
and  although  no  leaves  are  produced  a  few  roots  are  generally  found  to  be  formed  or  in 
the  act  of  forming  when  the  winter  has  passed  and  the  season  for  planting  has  come 
round.  In  thjs  state  they  are  taken  to  the  fields  and  planted.  The  w  eathcr  during  the 
planting  season  is  generally  showery,  as  this  happens  about  the  change  of  the  monsoon, 
when  the  air  is  charged  with  moisture.  A  few  days  of  this  warm  showery  weather  is  suffi- 
cient to  establish  the  new  crop,  which  now  goes  on  growing  with  luxuriance  and  requires 
little  attention  during  the  summer,  indeed  none  except  keeping  the  land  free  from  weeds. 
In  the  country  where  this  dye  is  manufactured  there  are  numerous  pits  or  tanks  on  the 
edge  of  the  fields.  They  are  usually  circular  in  form,  and  have  a  diameter  of  about  11 
feet  and  a  depth  of '2  feet.  About  400  catties*  of  stems  and  leaves  are  thrown  into  a 
tank  of  this  size,  which  is  then  filled  to  the  brim  with  clear  water.  In  five  days  the  plant 
is  partially  decomposed,  and  the  water  has  become  yellowish-green  in  color.  At  this 
period  the  whole  of  the  stems  and  leaves  are  removed  from  the  tank  with  a  flat-headed 
broom  made  of  bamboo  twigs.  When  every  particle  has  been  removed,  the  workmen 
employed  give  the  water  a  circular  and  rapid  motion  with  the  brooms  just  noticed,  which 
is  continued  for  some  time.  During  this  part  of  the  operation  another  man  has  employed 
himself  in  mixing  about  thirty  catties  of  lime  with  water,  which  water  has  been  taken  out 
of  the  tank  for  the  purpose.  This  is  now  thrown  into  the  tank,  and  the  rapid  circular 
motion  of  the  water  is  kept  up  for  a  few  minutes  longer.  When  the  lime  and  water 
have  been  well  mixed  in  this  way  the  circular  motion  is  allowed  to  cease.  Four  men  now 
station  themselves  round  the  tank  and  commence  beating  the  water  with  bamboo  rakes 
made  for  this  purpose.  The  beating  process  is  a  very  gentle  one.  As  it  goes  on,  the 
water  gradually  clianges  from  a  greenish  hue  to  a  dingy  yellow,  while  the  froth  becomes 
of  a  beautiful  bright  blue.  During  the  process  the  head  workman  takes  a  pailful  of  the 
liquid  out  of  the  tank  and  beats  it  rapidly  with  his  hand.  Under  this  operation  it  changes 
color  at  once,  and  its  value  is  judged  of  by  the  hue  it  presents.  The  beating  process  gen- 
erally lasts  for  about  half  an  hour.  At  the  end  of  this  time  the  whole  of  the  surface  of  the 
li(iuid  is  covered  with  a  thick  coating  of  froth  of  the  most  brilliant  colors,  in  which  blue 
predominates,  especially  near  the  edges.  At  this  stage,  it  being  desirable  to  incorporate 
the  froth  with  the  liquid  below  it,  it  is  only  necessary  to  throw  a  small  quantity  of  cab- 
bage oil  on  the  surface  of  the  froth.  The  workmen  then  stir  and  beat  it  gently  with  their 
flat  brooms  for  a  second  or  two,  and  the  whole  instantly  disappears.  The  liquid,  which 
is  now  darker  in  color,  is  allowed  to  repose  for  some  hours,  until  the  coloring  matter 
has  sunk  to  the  lower  stratum,  when  about  two-thirds  of  the  liquid  is  drawn  off  and  thrown 
away.     The  remaining  third  part  is  then  drawn  into-a  small  square  tank  on  a  lower  level, 

*  A  Chinese  catty  is  equal  to  IJ  lbs. 


INDIGO. 


609 


which  is  thatched  over  with  straw,  and  here  it  remains  for  three  or  four  days.  By  this 
time  the  coloring  matter  has  separated  itself  from  the  water,  which  is  now  entirely 
drained  off,  the  dye  occupying  three  or  four  inches  of  the  bottom  in  the  form  of  a  thick 
paste  and  of  a  beautiful  blue  color.  In  this  state  it  is  packed  in  baskets  and  exposed  for 
sale  in  all  the  country  towns  in  this  part  of  China.  Like  the  Shanghae  indigo,  made  from 
Isatis  indigotica,  it  is  called  '''■  T'ien-cking''''  by  the  Chinese. — Gardne/s  Chronicle  and 
Agricultural  Gazette,  April  8tli,  1854. 

The  cultivation  of  indigo  in  Central  America  has  fallen  off  very  much  of  late  years. 
Nicaragua  formerly  exported  annually  about  5,000  bales  of  150  lbs.  each.  At  present  the 
export  probably  does  not  exceed  1,000  or  2,000  bales.  Under  the  government  of  Spain, 
the  state  of  San  Salvador  produced  from  8,000  to  10,000  bales  annually.  A  piece  of 
ground  equal  to  two  acres  generally  produces  from  100  to  120  lbs.,  at  a  cost  of  not  far 
from  30  to  40  dollars. 

There  is  an  indigenous  biennial  plant  abounding  in  many  parts  of  Central  America, 
which  produces  indigo  of  a  very  superior  quality,  but  gives  less  than  half  the  weight  which 
is  afforded  by  the  cultivated  species.  Tlie  Indigofera  disperma  is  the  species  employed 
in  cultivation.  It  attains  its  highest  perfection  in  the  richest  soils.  It  will  grow,  how- 
ever, upon  almost  any  soil,  and  is  very  little  affected  by  drought  or  by  superabundant 
rains.  In  planting  it,  the  ground  is  perfectly  cleared,  usually  burnt  over,  and  divided 
with  an  implement  resembling  a  hoe  into  little  trenches,  2  or  3  inches  in  depth,  and  12 
or  14  apart,  at  the  bottom  of  which  the  seeds  are  strewn  by  hand,  and  lightly  covered 
with  earth.  A  bushel  of  seed  answers  for  4  or  5  acres  of  land.  In  Nicaragua  it  is 
usually  planted  towards  the  close  of  the  dry  season  in  April  or  Slay,  and  attains  its  per- 
fection for  tile  purpose  of  manufacture  in  from  two  and  a  half  to  three  months.  During 
this  time  it  requires  to  be  carefully  weeded,  to  prevent  any  mixture  of  herbs,  which 
would  injure  the  quality  of  the  indigo.  When  it  becomes  covered  with  a  kind  of  green- 
ish farina,  it  is  in  a  fit  state  to  be  cut.  This  is  done  with  knives  at  a  little  distance  above 
the  root,  so  as  to  leave  some  of  the  branches,  called  in  the  AVcst  Indies  "ratoons,"  for  a 
second  growth,  which  is  also  in  readiness  to  be  cut  in  from  six  to  eight  weeks  after. 
The  crop  of  the  first  year  is  usually  small ;  that  of  the  second  is  esteemed  the  best,  although 
that  of  the  third  is  hardly  inferior.  It  is  said  that  some  fields  have  been  gathered  for 
ten  consecutive  years  without  being  re-sown,  the  fallen  seed  obviating  the  necessity  of  new 
plantings. 

After  the  plant  is  cut,  it  is  bound  in  little  bundles,  carried  to  the  vats,  and  placed  in 
layers  in  the  upper  or  larger  one  called  the  steeper,  (mojadora.)  This  vat  holds  from  1,000 
to  10,000  gallons,  according  to  the  requirements  of  the  estate.  Boards  loaded  with 
weights  are  then  placed  upon  the  plants,  and  enough  water  let  on  to  cover  the  whole, 
which  is  now  left  to  steep  or  ferment.  The  rapidity  of  this  process  depends  much  upon 
the  state  of  the  weather  and  the  condition  of  the  plant.  Sometimes  it  is  accomplished 
in  6  or  8  hours,  but  generally  requires  from  15  to  2i).  The  proper  length  of  time  is  deter- 
mined by  the  color  of  the  saturated  water ;  but  the  great  secret  is  to  check  the  fermen- 
tation at  the  proper  point,  for  upon  this,  in  a  great  degree,  depends  the  quality  of  the 
product.  Without  disturbing  the  plant,  the  water  is  now  drawn  off  by  cocks  into  the 
lower  vat  or  "  beater,"  (golpeadoro,)  where  it  is  strongly  and  incessantly  beaten,  in  the 
smaller  estates  with  paddles  by  hand,  in  the  larger  by  wheels  turned  by  horse  or  water 
power.  This  is  continued  until  it  changes  from  the  green  color,  which  it  at  first  displays,  to 
a  blue,  and  until  the  coloring  matter,  or  flocculas,  shows  a  disposition  to  curdle  or  subside. 
This  is  sometimes  hastened  by  the  infusion  of  certain  herbs.  It  is  then  allowed  to  settle, 
and  the  water  is  carefully  drawn  off.  The  pulp  granulates,  at  which  time  it  resembles  a 
tine  soft  clay ;  after  which  it  is  put  into  bags  to  drain,  and  then  spread  on  cloths  in  the 
sun  to  dry.  When  properly  dried,  it  is  carefully  selected  according  to  its  quality,  and 
packed  in  hide  cases,  150  lbs.  each,  called  serojis.  The  quality  has  not  less  than  9  grada- 
tions, the  best  being  of  the  highest  figure.  From  G  to  9  are  called _/?orfs,  and  are  the  best ; 
from  3  to  6  cor/es :  from  1  to  3,  inclusive,  cobres.  The  two  poorer  qualities  do  not  pay 
expenses.  A  mansana  of  100  yards  square  produces  on  an  average  about  one  seroon  at 
each  cutting.  After  the  plant  has  passed  through  the  vats,  it  is  required  by  law  that  it 
shall  be  dried  and  burnt;  because  in  decomposing  it  generates  by  the  million  an  annoy- 
ing insect  called  the  "indigo  fly." 

The  following  account  of  the  manufacture  of  indigo  on  the  Senegal  is  taken  from 
Perottct's  "  Art  de  I'lndigotier :  " 

The  land  destined  to  the  cultivation  of  the  plant  ought  to  be  perfectly  level  and  free 
from  undulations,  so  as  to  prevent  the  seed  from  being  washed  into  the  hollows  or  lower 
parts  by  the  heavy  rains  so  frequent  in  the  tropics.  Soils  of  a  grayish  color  abounding  in 
•clay  are  not  adapted  for  the  purpose,  as  they  arc  too  compact  and  cold.  Sandy  soils  of 
a  whitish  color  must  also  be  avoided.  Light  soils,  abounding  iu  Immus  or  vegetable 
remains,  and  having  a  color  between  gray  and  dark  brown,  are  to  be  preferred  to  all 
others.  The  soil  should,  at  all  events,  not  be  one  very  retentive  of  moisture.  The 
Vol.  III.— 39 


610  INDIGO. 

quantity  of  indigo  obtained  from  the  came  weight  ot  plant  may  vary,  according  to  the 
soil,  from  4  lbs.  to  10  lbs.,  and  the  quality  also  varies  in  a  corresponding  degree.  The 
extent  of  ground  which  is  required  for  the  production  of  indigo  on  a  large  scale  is  so  great 
that  the  use  of  manure  becomes  almost  impossible.  Nevertheless  the  employment  of  the 
refuse  of  the  plant,  after  the  extraction  of  the  indigo,  as  a  manure  on  fresh  plantations,  is 
found  to  be  attended  with  very  beneficial  results.  The  ground,  if  new,  must  be  turned 
up  by  means  of  a  plough  or  hoe,  to  the  depth  of  at  least  10  or  12  inches,  three  times 
Euccessivelv  at  intervals  of  3  months,  before  the  sowing  takes  place.  The  sowing  must 
only  be  undertaken  in  fine  weather,  never  during  heavy  rain.  The  seed  employed  should 
be  perfectly  ripe,  and,  if  possible,  not  more  than  one  year  old.  It  is  to  be  left  in  the 
seed-vessels  in  which  it  is  contained  until  the  time  when  it  is  wanted.  The  latter  are 
then  put  into  a  wooden  mortar  and  reduced  to  fragments,  and  the  seed  is  separated  by  win- 
nowing from  the  dust,  debris,  &c.,  with  w  hich  it  is  mixed.  The  sowing  is  to  be  effected 
broadcast  and  as  evenly  as  possible.  It  should  take  place,  if  possible,  just  before  the 
approach  of  rain,  in  which  case  the  use  of  a  harrow  is  not  required,  as  the  rain  generally 
has  the  effect  of  completely  levelling  the  ground  and  covering  up  the  seed  with  soil. 
The  Indigofera  tinctoria,  and  its  varieties  macrocarpa  and  emarginata,  being  a  plant  with 
numerous  crowded  branches,  it  is  not  necessary,  in  sowing  it,  to  take  more  than  from  6 
to  7^  kilogrs.  of  seed  to  1  arpent  of  ground  ;  but  the  Indigofera  anil,  being  more  spar- 
ingly branched,  and  therefore  taking  up  less  room,  retjuires  to  be  more  thickly  sown. 
At  about  ten  or  twelve  days  after  sowing,  when  the  young  indigoferEe  have  attained  a 
height  of  about  81  to  lOS' millimetres,  the  ground  must  be  carefully  weeded,  and  this 
operation  must  be  repeated  as  soon  as  the  weeds  have  again  made  their  appearance  and 
commenced  to  interfere  with  the  growth  of  the  crop.  When  the  season  is  favorable, 
three  months  are  generally  sufficient  to  enable  the  plants  to  attain  the  degree  of  develop- 
ment necessary  for  the  production  of  indigo.  At  the  period  when  inflorescence  com- 
mences the  plant  is  far  richer  in  coloring  matter  than  at  any  other.  As  soon,  therefore, 
as  there  are  any  indications  of  flowering,  and  when  the  lower  leaves,  in  the  axils  of  w  hich 
the  flowers  appear,  begin  to  acquire  a  yellowish  tint,  and  when  pressed  in  the  hands 
produce  a  small  crackling  noise,  no  time  must  be  lost  in  cutting  down  the  plant.  This 
is  effected  by  means  of  good  knives  or  sickles,  and  as  near  the  ground  as  possible.  The 
stems,  after  being  cut,  are  tied  together  into  bundles  or  sheaves  and  carried  to  the  manu- 
factory. Since  the  coloring  principle  of  the  indigoferai  is  extremely  susceptible  of  change 
by  the  action  of  destructive  agencies,  it  is  necessary  to  use  the  utmost  despatch  in 
gathering  the  crop,  and  to  have  the  manufactory  of  such  a  size  in  proportion  to  the 
plantation,  that  no  time  may  be  lost  in  working  up  the  material  as  soon  as  gathered. 
The  plants  must  on  no  account  be  cut  when  they  are  moistened  either  with  rain  or  dew, 
because  in  this  case  they  acquire  a  blackish  tint  in  consequence  of  the  friction  to  which 
they  are  exposed  in  cutting  them  and  taking  them  to  the  manufactory,  this  tint  being  a 
sign  of  the  disappearance  of  the  coloring  matter.  Besides  this,  it  has  been  observed  that 
during  the  continuance  of  rain  the  indigo-producing  principle  diminishes  very  consider- 
ably, and  sometimes  even  disappears  entirely,  so  that,  if  cut  during  or  immediately  after 
rain,  the  plants  yield  little  or  no  indigo.  The  indigo  plant  is  subject  to  the  attack  of  a 
green  caterpillar,  which  sometimes  appears  in  such  quantities  as  to  destioy  the  w hole  crop. 
No  certain  and  easy  means  of  destroying  this  pest  is  known.  It  has  been  recommended 
to  pass  wooden  rollers  over  the  ground,  before  the  plants  have  attained  any  great  size, 
so  as  to  crush  the  caterpillars  without  injuring  the  plants,  and  this  plan  has  been  attended 
with  partial  success. 

In  order  to  obtain  good  results  in  the  manufacture  of  indigo,  it  is  necessary  that  the 
plants  should  be  of  the  same  age,  of  the  same  species,  and  from  the  same  field.  The 
Indigofera  anil  begins  to  ferment  several  hours  sooner  than  the  /.  finctoria,  r-o  that  if  a 
mixture  of  both  be  taken,  the  produce  from  either  one  or  the  other  will  be  lost,  and  the 
indigo  obtained  will  also  be  of  a  bad  quality.  The  plants  should,  as  soon  as  possible 
after  being  gathered,  be  placed  in  the  steeping-vat,  which  is  a  vessel  built  of  bricks,  and 
well  lined  with  cement,  from  3|  to  8  metres  in  length,  of  the  same  width,  and  about  1 
metre  deep.  In  this  vessel  the  plants  are  arranged  in  successive  layers,  the  lower  layers 
being  slightly  inclined  towards  one  end,  in  order  to  facilitate  the  subsequent  running  off 
of  the  hqiior.  The  vessel  being  full,  a  number  of  poles  of  fir-wood  are  laid  lengthways 
over  the  plants,  at  a  distance  of  162  mill,  from  one  another.  Three  beams  are  then  laid 
crosswise  over  the  poles,  their  ends  being  well  secured  by  passing  them  through  slits 
which  are  cut  in  the  upright  posts  at  the  sides  of  the  cistern,  and  then  fixing  them  by 
means  of  iron  pins,  passing  through  holes  in  the  posts.  By  this  means  the  plants  are 
prevented  from  rising  above  the  surface  of  the  liquor  during  the  process  of  maceration. 
The  vat  is  now  filled  with  water  from  an  adjacent  cistern,  in  which  it  has  been  allowed  to 
stand  for  24  hours  for  the  purpose  of  allowing  all  foreign  matters  contained  in  it  to  be 
deposited.  After  standing  in  contact  with  the  leaves  for  about  6  hours,  a  change 
usually  begins  to  manifest  itself  in  the  liquor,  which  must  therefore,  from  that  time  for- 


INDIGO  611 

ward,  be  carefully  watched.  As  Roon  as  this  liquor  begins  to  acquire  a  green  color,  and 
when  a  little  of  it,  on  being  kept  for  a  short  time  in  the  moutii,  leaves  a  slight  impression 
of  harshness  [dprete)  on  the  tongue  and  the  palate,  it  is  a  sign  that  the  maceration  is  com- 
plete, and  that  the  liquor  should  be  drawn  otf  without  delay.  If  this  be  not  done,  the 
color  of  the  liquor  changes  from  green  to  brawn,  a  new  species  of  fermentation  com- 
mences, accompanied  by  the  formation  of  acetic  acid,  and  the  plant  begins  to  yield  sub- 
stances of  a  mucilaginous  nature,  which  contaminate  the  indigo,  and  completely  spoil  its 
quality  It  is  therefore  of  the  greatest  importance  to  ascertain  ex;ictly  when  the  macer- 
ation of  the  plant  is  complete.  The  following  are  the  chief  indications  of  this  ])oint 
having  been  attained:  1.  When  the  water,  which  was  at  first  clear,  begins  to  become 
muddy  and  acquire  a  slight  greenish  tinge.  2.  When  bubbles  of  a  greenish  color  rise  to 
the  surface  here  and  there.  3.  When  towards  the  edge  of  the  vat  some  mucilage,  or  a 
kind  of  grayish  scum,  commences  to  be  iormcd.  4.  When  a  very  slight  purple  pellicle 
is  observed  on  the  surface  of  the  liquor,  especially  near  the  corners  of  tlie  vat.  5.  Wlien 
the  liquor  begins  lo  exhale  a  slight  but  not  disagreeable  odor  of  herbs.  When  the  fer- 
mentation has  proceeded  too  far,  the  following  phenomena  present  themselves:  1.  A 
considerable  quaniity  of  large  bubbles  of  air  are  disengaged,  which  burst  at  the  surface, 
forming  a  layer  of  grayish  mucilage.  2.  The  surface  of  the  liquor  becomes  covered 
with  a  copper-colored  pellicle.  3.  A  heaving  of  the  liquor  in  the  vat  is  observed,  giving 
rise  to  the  disengagement  of  large  greenish  bubbles  which  communicate  a  brownish  color 
to  the  water.  4.  The  liquor  acquires  a  fetid  smell,  a  strongly  acid  taste,  and  a  soapy 
appearance.  These  phenomena  manifest  themselves  when  the  weather  is  hot,  after  the 
fermentation  has  continued  about  12  or  14  hours.  It  then  becomes  impossible  to  obtain 
indigo  of  good  quality,  the  only  product  being  a  black  matter  resembling  wax. 

The  liquor  is  now  run  off  from  the  steeping-vat  into  the  beater,  which  is  a  cistern  of 
about  the  same  dimensions  as  the  former,  but  situated  at  a  rather  lower  level.  Here  it  is 
subjected  to  the  beating  process,  the  object  of  which  is  to  expose  the  reduced  indigo  to  the 
oxygen  of  the  atmosphere,  as  well  as  to  promote  the  disengagement  of  the  carbonic  acid 
gas  with  which  the  liquid  is  charged,  and  which  prevents  the  precipitation  of  the  indigo. 
The  beating  is  performed  by  men,  who,  provided  with  paddles,  agitate  the  liquid  rapidly,  so 
as  to  bring  every  part  of  it  successively  into  contact  with  the  air.  It  is  of  importance  that 
this  process  should  be  broken  off  at  the  right  moment,  for  if  it  be  continued  too  long, 
the  grain  formed  at  first  will  redissolve  and  be  lost.  And  if,  on  the  other  hand,  it  be 
arrested  before  the  proper  time  has  arrived,  a  portion  of  the  indigo  will  remain  unpre- 
cipitafed.  In  order  to  ascertain  in  what  state  the  liquor  is,  a  little  of  it  nmst  be  poured 
into  a  drinking-glass  and  mixed  with  an  equal  volume  of  clear  water.  If  there  is  formed 
round  the  circumference  of  the  glass  a  line  of  a  bluish-green  color,  the  beating  must  be 
continued ;  but  if,  on  the  contrary,  the  liquid  appears  of  a  uniform  browMi  color,  and 
if  ou  adding  to  it  a  few  drops  of  clear  lime  water  with  the  finger  the  indigo  precipitates 
immediately  in  grains,  the  process  must  be  arrested.  The  beating  usually  occupies  from 
an  hour  and  a  half  to  two  hours.  The  liquid  is  now  to  be  well  mixed  with  about  '/lo  of 
its  volume  of  clear  lime  water,  and  allowed  to  rest  until  the  indigo  has  quite  settled.  By 
opening  successively  the  plugs  which  are  placed  at  different  heights  in  the  side  of 
the  vessel,  the  clear  liquor  is  then  drawn  off  in  separate  portions  and  permitted  to  run 
away,  care  being  taken  that  none  of  the  indigo  is  allowed  to  be  carried  away  with  the 
water.  By  means  of  an  opening  situated  near  the  bottom  of  the  beating-vat  the  indigo 
mixed  with  water  is  then  run  off,  and,  flowing  through  a  canal,  is  received  on  a  cloth 
strainer  or  filter.  This  filter  rests  on  a  round  or  four-cornered  vessel,  the  top  of  which  is 
on  a  level  with  the  surface  of  the  ground,  and  which  is  called  the  diablotin.  When  the 
liquor  has  run  through  the  filter,  the  indigo  which  remains  behind  in  a  state  of  paste  is 
mixed  up  again  with  water,  and  the  mixture  is  poured  on  a  canvas  filter  and  allowed  to 
run  immediately  into  the  boiler.  The  refuse  matter,  consisting  of  leaves  of  the  plant, 
&c.,  remains  on  the  canvas,  while  the  indigo  suspended  in  water  runs  through.  Tlie 
boiler  is  a  vessel  with  sides  of  masonry  and  a  bottom  consisiing  of  a  copper  plate  which 
rests  on  iron  bars,  and  is  well  cemented  to  the  sides.  Underneath  the  copper  plate  is 
the-fire-place.  The  top  must  be  covered  with  a  wooden  lid,  consisting  of  two  flaps  which 
are  fixed  to  hinges  at  the  sides,  and  meet  together  over  the  top.  At  the  moment  when 
the  mixture  of  indigo  and  water  is  introduced  into  the  boiler,  the  latter  must  already  be 
about  one-third  full  of  hot  water,  the  mixture  lieing  sufficient  almost  to  fill  it  entirely. 
The  heat  is  now  raised  gradually  to  the  boiling  point,  and  the  boiling  is  continued  lor 
about  two  hours.  In  order  to  prevent  the  indigo  from  adhering  to  the  bottom  and  sides 
of  the  boiler,  the  liquor  must  be  kept  continually  slirred  with  a  wooden  riike.  Tlic  ob- 
ject of  the  boiling  is  to  drive  away  all  tiic  carbonic  acid  that  mny  still  be  present  in  the 
liipior,  to  remove  the  soluble  extractive  matters  which  would  render  the  indigo  dull  and 
impure,  to  prevent  the  fermentation  or  putrefaction  of  the  indigo  which  would  otherwise 
take  place,  and,  lastly,  to  facilitate  the  subsequent  processes  of  filtering  and  pressing. 
The  fire  having  been  removed,  the  liquor  is  allowed  to  stand  for  some  time,  and  as  soon 


612  INDIGO. 

as  the  indigo  has  settled  the  supernatant  liquid  is  drawn  off  by  means  of  taps  fixed  in 
one  of  the  sides  of  the  boiler.  The  lowest  tap  is  then  opened,  and  the  indigo  is  run  off 
with  the  water  and  received  on  a  filter,  consisting  of  blue  Guinea  cloth  stretched  on  a 
frame.  The  first  portions  of  hquid  which  run  through  are  usually  colored  with  indigo, 
and  must  therefore  be  caught  in  a  suitable  vessel  and  poured  on  the  filter  again.  As 
soon  as  the  liquid  has  percolated,  the  indigo,  which  is  new  a  compact  paste,  is  removed 
from  the  filter  by  means  of  a  wooden  ladle  and  put  into  a  press,  which  consists  of  a 
wooden  box  pierced  with  holes.  The  press  having  been  lined  with  cloth,  the  indigo  is 
put  in,  the  cloth  is  folded  round  it  as  evenly  as  possible,  a  wooden  Hd  is  dropped  on  the 
cloth,  and  the  mass  is  submitted  to  pressure  by  means  of  a  screw,  until  no  more  liquid 
runs  through  at  the  bottom,  which  takes  place  as  soon  as  the  indigo  lias  been  reduced 
to  about  a  third  of  its  original  volume.  The  press  is  then  opened,  the  indigo  is  taken 
out  of  the  cloth,  laid  on  a  table,  and  divided  )>y  means  of  a  knife  into  pieces  of  a  cubical 
shape.  These  cubes  are  then  taken  to  the  drying-shed,  where  they  are  placed  on  trellises 
covered  with  matting  or  very  thin  cloth,  so  as  to  adniitof  the  free  passage  of  air.  Care  must 
be  taken  not  to  dry  them  too  rapidly,  otherwise  the  cakes  would  crack  and  split  into 
fragments,  which  are  then  of  little  commercial  value,  and  it  is  therefore  necessary  to 
protect  them  from  currents  of  dry  air  by  covering  them  with  canvas  or  Guinea  cloth. 
During  the  drying  process,  which  occupies  from  8  to  10  days,  the  cakes  should  be  tuined 
several  times.  They  are  then  closely  packed  in  boxes,  each  box  holding  about  25  kilo- 
giammes.     The  boxes  shotdd  be  lined  with  paper. 

It  may  be  remarked,  that  when  the  indigo  is  of  good  quality,  the  volume  of  the  paste 
diminishes  very  little  when  subjected  to  pressure.  If  the  process  of  filtering  takes  up  much 
time  and  the  pressing  is  attended  with  difficulty,  it  may  be  anticipated  that  the  indigo  will 
turn  out  of  bad  quality.  This  may  proceed  from  the  plant  having  been  overgrown,  or  from 
the  maceration  or  the  beating  process  having  been  continued  too  long,  or  from  the  employ- 
ment of  too  large  a  quantity  of  lime  water.  The  difficulty  experienced  in  pressing  the 
indigo  paste,  and  which  is  often  so  great  as  to  cause  the  cloth  in  which  it  is  enveloped  to 
break,  is  caused  by  the  presence  of  a  mucilaginous  or  viscous  substance  mixed  with  the 
indigo,  which  may  be  removed  by  treating  the  paste  again  with  boiling  water,  and  repeating 
the  operations  of  filtering  and  pressing. 

In  reo'ard  to  the  state  in  which  indigo  exists  in  the  plants  from  which  it  is  derived,  and 
the  nature  of  the  process  by  which  it  is  obtained,  various  opinions  have  been  entertained  by 
chemists.  Berthollet,  in  his  work  on  dyeing,  says,  "  that  the  three  parts  of  the  process 
employed  have  each  a  different  object.  In  the  first  a  fermentation  is  excited,  in  which  the 
action  of  the  atmospheric  air  does  not  intervene,  since  an  inflammable  gas  is  evolved. 
There  probably  results  from  it  some  change  in  the  composition  of  the  coloring  particles 
themselves ;  but  especially  the  separation  or  destruction  of  a  yellowish  substance,  which 
gave  to  the  indigo  a  greenish  tint,  and  rendered  it  susceptible  of  undergoing  the  chemical 
action  of  other  substances.  This  species  of  fermentation  passes  into  a  destructive  putrefac- 
tion, because  the  indigo  has  a  composition  analogous  to  that  of  animal  substances.  Hitherto 
the  coloring  particles  have  preserved  their  liquidity.  In  the  second  operation,  the  action 
of  the  air  is  brought  into  play,  which,  by  com))ining  with  the  coloring  particles,  deprives 
them  of  their  solubility,  and  gives  them  the  blue  color.  The  beating  serves,  at  the  same 
time,  to  dissipate  the  carbonic  acid  which  is  formed  in  the  first  operation,  and  which  by  its 
action  presents  an  obstacle  to  the  combination  of  the  oxygen.  The  separation  of  this  acid 
is  promoted  by  the  addition  of  lime ;  but  if  an  excess  be  introduced,  it  counteracts  the  free 
combination  of  the  oxygen.  The  third  part  of  the  process  has  for  its  objects,  the  deposition 
of  the  coloi-ing  matter,  become  insoluble  by  combination  with  oxygen,  its  separation  from 
foreign  substances,  and  its  desiccation,  which  gives  it  more  or  less  hardness,  whence  its  ap- 
pearance varies."  De  Cossigiiy  was  of  opinion  that  volatile  alkali  was  the  agent  by  which 
the  coloring  matter  was  extracted  from  the  plant  and  held  in  solution  until  volatilized  by 
the  agitation  process.  Roxburgh  concluded  from  his  experiments,  "  that  the  indigo  plants 
contain  only  the  base  of  the  color,  which  is  naturally  green ;  that  much  carbonic  acid  is 
disengaged  during  its  extraction  from  the  leaves;  that  the  carbonic  acid  is  the  agent 
whereby  it  is  probably  extracted  and  kept  dissolved ;  that  ammonia  is  not  formed  during 
the  process ;  that  the  use  of  the  alkalies  employed  is  to  destroy  the  attraction  between  the 
base  and  the  carbonic  acid ;  and  that  the  vegetable  base,  being  thereby  set  at  liberty,  com- 
bines with  some  coloring  principle  from  the  atmosphere,  forming  therewith  a  colored  insolu- 
ble fecula,  which  falls  to  the  bottom  and  constitutes  indigo." 

Chevreul,  who  was  the  first  chemist  of  any  eminence  to  examine  the  indigo-bearing 
plants  and  their  constituents,  inferred  from  his  analyses  of  the  Ixafin  tindoria  and  the 
Indigofcra  anil,  that  these  plants  contain  indigo  in  the  white  or  reduced  state,  in  the  same 
state  in  which  it  exists  in  the  indigo  vat ;  that  in  this  state  it  is  held  in  solution  by  the  vege- 
table juices,  and  that  when  the  solution  is  removed  from  the  plant  it  is  converted  by  the 
action  of  the  atmospheric  oxygen  into  indigo-blue.  Giobert,  from  an  examination  of  the 
hatis  tinctorin,  drew  the  following  conclusions:    1.  Indigo-blue  does  not  preexist  in  the 


INDIGO.  613 

plant,  but  is  formed  during  the  operations  by  means  of  which  we  believe  it  to  be  extracted. 
2.  There  exists  in  a  small  number  of  plants  a  peculiar  principle,  different  from  all  the 
known  proximate  constituents  of  plants,  and  which  has  the  property  of  being  convertible 
into  indigo ;  this  principle  may  be  called  indigoc/ene.  3.  This  principle  differs  from  indigo 
in  containing  an  excess  of  carbon,  of  which  it  loses  a  portion,  in  passing  into  the  state  of 
indigo-blue,  by  the  action  of  a  small  quantity  of  oxygen  which  it  takes  up.  4.  The  loss  of 
this  portion  of  carbon  must  be  attributed  to  its  undergoing  combustion  and  being  converted 
into  carbonic  acid.  5.  It  differs  in  its  properties  from  common  indigo  in  being  colorless 
and  soluble  in  water,  and  by  its  greater  combustibility,  which  causes  it  to  undergo  sponta- 
neous combustion  at  the  ordinary  temperature  of  the  atmo.sphere.  6.  Its  combustibility  is 
enhanced  by  heat  and  by  combination  with  alkalies,  especially  lime ;  it  is  diminished  by  the 
action  of  all  acids,  even  carbonic  acid.  About  the  year  1839,  the  Pylogonum  tinctorium,  an 
indigo-bearing  plant  indigenous  to  China,  became  the  subject  of  a  series  of  investigations  by 
several  French  chemists,  chiefly  with  a  view  to  ascertain  whether  this  plant,  if  grown  in 
France,  could  be  advantageously  employed  in  the  preparation  of  a  dyeing  material  as  a  sub- 
stitute for  foreign  indigo.  Baudrimont  and  Pelletier,  after  an  examination  of  this  plant, 
arrived  at  the  conclusion  that  the  indigo  is  contained  in  it  as  reduced  indigo,  in  the  same 
state  as  it  is  in  woad,  according  to  Chevreul.  Robiquet,  Colin,  Turpin,  and  Joly,  on  the 
other  hand,  expressed  a  very  decided  conviction  that  indigo-blue  preexists  in  the  plant,  but 
not  in  a  free  state ;  that  it  is  combined  witli  some  organic  .substance  or  substances  which  ren- 
der it  soluble  in  water,  ether,  and  alcohol ;  and  that  the  operation  of  potent  agencies  is  requi- 
site in  order  to  destroy  this  combination  and  set  the  indigo  at  liberty.  The  explanation  of 
Chevreul,  proceeding  from  an  authority  of  such  eminence,  and  being  the  simplest,  has  been 
adopted  by  most  chemists.  Nevertheless  there  are  objections  to  it  which  render  it  inad- 
missible. Reduced  indigo  is  a  body  which  is  only  soluble  in  alkalies,  and  cannot,  there- 
fore, be  contained  as  such  in  the  juice  of  indigo  plants,  which  is  mostly  acid.  As  it  also 
takes  up  oxygen  with  the  greatest  avidity,  and  is  converted  into  indigo-blue,  it  is  difficult  to 
conceive  how  the  whole  of  it  can  be  preserved  in  a  colorless  state  in  the  cells  of  plants,  in 
which  it  must  occasionally  come  in  contact  with  the  oxygen  eliminated  by  the  vegetable 
organism.  If  these  plants  contained  reduced  indigo,  the  juice  ought,  moreover,  to  turn 
Ijlue  the  moment  it  became  exposed  to  the  atmosphere,  which  is  not  always  the  case.  The 
necessity  for  a  long  process  of  fermentation  in  order  to  obtain  the  coloring  matter  would 
also  not  be  very  apparent,  the  mere  contact  with  oxygen  being,  it  might  be  supposed,  all 
that  was  necessary  for  the  purpose.  The  facility  with  which  the  indigo-blue  is  destroyed  if 
the  process  of  fermentation  is  carried  too  far,  is  also  inconsistent  with  the  supposition  that 
it  is  contained  in  plants,  eitha-  as  such  or  in  a  deoxidized  state,  since  indigo-blue  is  a  body 
not  easily  decomposed,  except  iiy  very  powerful  agents. 

In  order  to  throw  some  light  on  this  subject,  an  investigation  was  undertaken  by 
Schunck  into  the  state  in  whicli  indigo-blue  exists  in  the  Isatis  tinctoria,  or  common  woad, 
which  is  the  only  plant  indigenous  to  Europe  that  yields  any  considerable  quantity  of  the 
coloring  matter.  Schunck  succeeded  in  obtaining  from  that  plant  a  substance  of  very  pe- 
culiar properties,  to  which  he  gave  the  name  of  Indican.  This  substance  has  the  appear- 
ance of  a  yellow  or  light  brown  transparent  syrup.  It  has  a  bitter  taste.  It  is  very  easily 
soluble  in  water,  alcohol,  and  ether ;  its  solutions  are  3'ellow,  and  have  an  acid  reaction. 
Its  compounds  with  bases  are  yellow.  When  its  watery  solution  is  mixed  with  a  strong 
acid,  such  as  muriatic  or  sulphuric  acid,  no  change  takes  place  at  first,  but  on  leaving  the 
solution  to  stand,  or  on  heating  it,  it  becomes  blue  and  opalescent,  then  acquires  a  purple 
color,  and  at  length  deposits  a  quantity  of  purplish-blue  flocks,  which  are  quite  insoluble  in 
water.  These  flocks  consist  for  the  most  part  of  indigo-blue,  but  they  contain  also  a  red 
coloring  matter  and  several  brown  substances  of  a  resinous  nature.  The  supernatant  liquid 
contains  a  peculiar  kind  of  sugar,  and  on  Ijeing  distilled  yields  carbonic,  formic,  and  acetic 
acids.  Hence  it  follows  that  the  plant  does  not  contain  indigo-blue  ready  formed,  either  in 
the  blue  or  colorless  state — that  the  latter  exists  in  the  vegetable  juice  in  a  state  of  combi- 
nation with  sugar,  forming  a  compound  of  that  peculiar  class  known  to  chemists  as  gluco- 
sides.  This  compound  is  readily  dissolved  by  water,  and  the  indigo-blue  may  then  be  lib- 
erated and  precipitated  from  the  solution  by  means  of  acids,  and  probably  also  by  other 
agents,  but  the  simultaneous  action  of  oxygen  is  not  necessary  during  the  process  of  decom- 
position which  the  compound  undergoes  in  yielding  indigo-blue.  Now  if,  as  seems  proba- 
ble, the  various  species  of  indigofei-a  contain  indican  or  some  similar  substance,  the  phe- 
nomena which  take  place  during  the  process  of  manufacturing  indigo  may  easily  be 
explained.  During  the  steeping  process  the  indican  is  dissolved,  and  in  consequence  of 
the  fermentation  which  then  takes  place  in  the  liquor  it  is  decomposed  into  indigo-blue  and 
sugar.  The  former  would  then  be  precipitated,  but  since  ammonia  is,  according  to  most 
■  authors,  evolved  at  the  same  time,  tiie  indigo-blue  is,  by  the  simultaneous  action  of  the 
alkali  and  the  sugar,  or  other  organic  matters  contained  in  the  li((uid,  reduced  and  dis- 
solved, forming  a  true  indigo  vat,  from  which  the  coloring  matter  is  afterwards  precipitated 
by  the  combined  action  of  the  atmospheric  oxygen  and  the  lime,  during  the  beating  juo- 


614  INDIGO. 

cess.  According  to  Schunck,  two  distinct  periods  may  be  observed  in  the  decomposition  of 
indican.  During  the  first  period,  indigo-blue  is  the  chief  product  of  decomposition ;  during 
the  second,  the  red  and  brown  resinous  matters  make  their  appearance  with  very  little 
indigo-blue.  The  formation  of  carbonic,  acetic,  and  formic  acids  is,  according  to  Schunck, 
dependent  on  that  of  the  brown  resinous  matters.  It  would  appear,  therelbre,  that  the 
copious  disengagement  of  carbonic  acid,  as  well  as  the  acid  taste,  attributed  to  acetic  acid, 
sometimes  observed  during  the  manufacture  of  indigo,  are  phenomena  which  indicate  the 
formation,  not  of  indigo-blue,  but  of  other  substances,  which  may  prove  very  injurious  to 
the  quality  of  the  indigo.  These  substances,  being  soluble  in  Jilkalies,  but  insoluble  in 
water,  are  precipitated,  as  soon  as  the  liquid  loses  the  alkaline  reaction  which  it  possesses 
at  the  commencement,  and  becomes  acid.  Though  indigo-blue  is  a  body  of  very  stable 
character,  not  easily  decomposed  when  once  formed,  except  by  potent  agencies,  still  the 
assertion  of  Perottct  and  others,  that  "  nothing  is  more  fugitive  and  more  liable  to  be  acted 
on  by  destructive  agencies  than  the  coloring  principle  of  the  indigofer?e,"  will  be  easily 
understood  when  the  following  facts,  mentioned  by  Schunck,  are  taken  into  consideration : 
If  a  watery  solution  of  indican,  this  indigo-producing  body,  be  boiled  for  some  time,  it  then 
yields  by  decomposition,  not  a  trace  of  indigo-blue,  but  only  indigo-red,  and  if  it  be  boiled 
with  the  addition  of  alkalies,  it  then  gives  neither  indigo-blue  nor  indigo-red,  but  only  the 
brown  resinous  matters  before  mentioned.  The  mere  action  of  alkalies  is  therefore  suffi- 
cient to  cause  the  molecules,  which  would  otherwise  have  gone  to  form  indigo-blue,  to 
arrange  themselves  in  a  totally  different  manner  and  yield  products  which  bear  very  little 
resemblance  to  it.  It  is  evident,  therefore,  that  one  of  the  chief  oljects  to  be  kept  in  view 
by  the  manufacturer  of  indigo,  is  the  proper  regulation  of  the  process  of  fermentation,  so  as 
to  prevent  the  formation  of  the  other  products,  which  take  the  place  of  indigo-blue,  and  are 
formed  at  its  expen.se. 

The  indigo  of  commerce  occurs  in  pieces,  which  are  sometimes  cubical,  sometimes  of  an 
irregular  form.  These  pieces  are  firm  and  dry,  and  are  easily  broken,  the  fracture  being 
dull  and  earthy.  It  is  sometimes  lighter,  sometimes  apparently  heavier  than  water,  this 
difference  depending  on  its  being  more  or  less  free  from  foreign  impurities,  as  well  as  upon 
the  treatment  of  its  paste  in  the  boiling,  pressing,  and  drying  operations.  Its  color  is  blue 
of  different  shades,  as  light  blue,  purplish  blue,  coppery  blue,  and  blackish  blue.  On  being 
rubbed  with  the  nail,  or  a  smooth  hard  body,  it  assumes  the  lustre  and  hue  of  copper.  It 
is  usually  a  homogeneous  mass,  but  it  occasionally  contains  grains  of  sand  or  other  foreign 
bodies,  and  sometimes  presents  inequalities  of  color.  It  is  frequently  full  of  small  cavities, 
which  proceeds  from  the  drying  process  having  been  conducted  too  rapidly,  and  it  is  also 
covered  at  times  with  a  whitish  matter  consisting  of  mould.  It  varies  very  much  in  con- 
sistency, being  sometimes  diy,  hard,  and  compact,  whilst  sometimes  it  is  easily  broken  into 
thin  flat  pieces.  Indigo  is  devoid  of  smell  and  taste.  When  applied  to  the  tongue,  how- 
ever, it  adheres  slightly,  in  consequence  of  the  property  which  it  possesses  of  lapidly  ab- 
sorbing moisture — a  property  which  is  often  had  recourse  to  in  order  to  ascertain  its  quality. 
When  thrown  on  red-hot  coals  it  yields  vapors  of  a  deep  purple  color,  which,  when  con- 
densed on  cold  bodies,  give  shining  needles  having  a  coppeiy  lustre.  It  is  insoluble  in 
water,  cold  alcohol,  ether,  muriatic  acid,  dilute  sulphuric  acid,  cold  ethereal  and  fat  oils; 
but  boiling  alcohol  and  oils  dissolve  a  little  of  it,  which  they  deposit  on  cooling.  Creosote 
has  the  property  of  dissolving  indigo. 

Indigo  varies  very  much  in  quality,  but  it  requires  much  discrimination  in  order  to 
judge  faiily  of  the  quality  of  any  sample  from  mere  inspection  and  afiplication  of  the  tests 
usually  employed  by  dealers.  A  cake  of  indigo  being  broken,  and  the  nail  or  the  edge  of 
a  .shilling  being  passed  with  a  tolerable  degree  of  pressure  over  the  fractured  part,  a  fine 
coppery  streak  will  be  produced  if  the  indigo  is  good.  If  the  indigo  furrows  up  on  each 
side  of  the  nail  it  is  weak  and  bad,  and  if  the  coppery  streak  be  not  very  bright  it  is  not 
considered  good.  When  a  jiiece  of  indigo  is  broken  the  fracture  should  be  held  up  to  the 
sun,  and  if  it  h;)s  not  ))een  well  strained  from  the  dros.s,  particles  of  sand  will  be  seen  glis- 
tening in  the  sun-light.  The  outside  or  coat  should  also  lie  as  free  from  sand  as  possible. 
When  the  squares  are  broken  in  the  chests  the  indigo  fetches  a  low  price,  and  if  it  is  very 
much  crushed  it  is  only  bought  by  the  consumers  for  immediate  use.  The  methods  em- 
ployed for  ascertaining  the  true  amount  of  coloring  matter  in  any  sam.ple  of  indigo  will  be 
described  below. 

Indigo  is  generally  classified  according  to  the  various  countries  from  which  it  is  obtained. 
The  principal  kinds  are  the  ibllowing:  Bengal,  Oude,  Madras,  Manilla,  Java,  Egyptian, 
Guatemala,  Caracc;i,s,  and  Mexican. 

At  the  present  diiy  the  finest  qualities  of  indigo  are  obtained  from  Bengal,  the  produce 
of  that  country  having  now  taken  the  place  in  public  estimation  which  was  once  occupied 
by  that  of  the  Spanish  colonies.  The  export  of  indigo  from  Bengal,  which  in  1853 
amounted  to  120,000  maunds,  (of  V-l  l))s.  10  oz.,)  would  require  for  its  culture  about 
1,025,000  acres,  and  an  annual  expenditure  of  £1,300,000.  Of  this  extent  of  land  about 
550,000  acres  are  believed  to  be  included  in  the  Lower  Provinces,  and  consist  chiefly  of 


INDIGO.  615 

alluvial  land  »escued  from  the  rivers.  The  best  qualities  of  Bengal  indigo  are  manufac- 
tured in  the  Jessore  and  Kishenaghaur  districts,  but  each  district  produces  a  quality  pecu- 
liar to  itself,  and  differences  of  a  less  striking  character  may  be  perceived  in  the  produce 
of  different  factories.  The  Bengal  indigo,  when  packed  in  chests,  consists  of  four  principal 
qualities,  viz.,  the  blue,  purple,  violet,  and  copper.  But  these  kinds,  by  passing  over  into 
one  another,  produce  a  number  of  intermediate  varieties,  such  as  purply  blue,  blue  and 
violet,  purply  violet,  &c.  The  various  qualities  would,  therefore,  be  distinguished  as 
follows:  1.  Blue.  2.  Blue  and  violet.  3.  Purple.  4.  Purple  and  violet.  5.  Violet. 
6.  Violet  and  copper.  7.  Copper.  The  leading  London  brokers,  however,  classify  Ben- 
gal indigo  into  the  following  grades :  fine  blue,  fine  purple  and  violet,  tine  red  and  violet, 
good  purple  and  violet,  middling  violet,  middling  defective,  consuming  fine,  middling  and 
good,  ordinary,  ordinary  and  lean  trash.  The  finest  qualities  of  Bengal  indigo  present  the 
following  characteristics :  They  consist  of  cubical  pieces,  are  light,  brittle,  of  a  clean  frac- 
ture, soft  to  the  touch,  of  a  fine  bright  blue  color,  porous,  and  adhering  to  the  tongue. 
The  lower  qualities  have  a  duller  color,  assume  more  and  more  of  a  reddish  tinge,  are 
heavier,  more  compact,  and  less  easily  broken. 

The  indigo  from  the  upper  provinces  of  India  comes  chiefly  from  Tyroot,  Oude,  and 
Benares.     It  is  inferior  to  Bengal  indigo. 

Of  Madras  indigo  there  are  two  kinds,  viz. :  1.  Dry  leaf,  made  from  dry  stacked  leaves; 
and,  2.  Kurpah,  which  is  manufactured  from  the  wet  leaf  in  the  same  way  as  Bengal  indigo. 
The  latter  has  only  come  into  use  since  1830.  Both  are  of  inferior  quality  to  Bengal 
indigo. 

The  Manilla  indigoes  present  the  marks  of  the  rushes  upon  which  they  have  been  dried. 
The  pieces  are  either  cubical,  or  flat  and  square,  or  of  irregular  shape.  The  quality  is  very 
unequal.  Java  indigo  occurs  in  flat,  square,  or  lozenge-shaped  masses,  the  quality  ap- 
proaching that  of  Bengal.  Both  these  kinds  are  consumed  chiefly  on  the  continent  of 
Europe. 

Guatemala  indigo  is  imported  into  this  country  in  serons  or  hide  wrappers,  each  con- 
taining about  150  lbs.  net.  It  occurs  in  small  irregular  pieces,  which  are  more  or  less 
brittle,  compact,  lighter  than  water,  and  of  a  bright  blue  color,  with  an  occasional  tinge  of 
violet.  There  are  three  kinds  of  Guatemala  indigo,  viz. :  1.  Flores,  which  is  the  best,  and 
approaches  in  quality  that  of  the  finer  Bengal  indigoes ;  2.  Sobres ;  and,  3.  Cortes,  which 
is  the  lowest  in  quality,  being  heavy,  difficult  to  break,  and  of  a  coppery-red  color.  Of  the 
first  kind  very  little  now  reaches  the  market.  The  indigo  of  Caraccas  is,  generally  speak- 
ing, inferior  to  that  of  Guatemala. 

The  manufacture  of  indigo  was  formerly  carried  on  in  St.  Domingo,  but  has  for  some 
time  been  entirely  abandoned. 

The  indigo  of  commerce,  even  when  not  adulterated,  is  a  mixture  of  different  matters. 
When  it  is  heated  in  a  state  of  fine  powder  to  212°  F.  it  loses  from  5  to  10  per  cent,  in 
weight,  the  loss  consisting  of  water.  When  the  dry  powder  is  heated  in  a  crucible  a  great 
part  of  it  burns  away,  and  there  is  left  at  last  a  grayish  ash,  consisting  of  the  carbonates 
and  phosphates  of  lime  and  magnesia,  sulphate  of  lime,  alumina,  oxide  of  iron,  clay,  and 
sand.  Tliese  matters  are  partly  derived  from  the  plant,  partly  from  the  lime  and  the  im- 
purities of  the  water  employed  in  the  manufacture.  The  quantity  of  inorganic  matter  con- 
tained in  ordinary  indigo  varies  very  much.  In  the  better  qualities  it  amounts  on  an 
average  to  aljout  10  per  cent,  of  the  weight;  whilst  in  the  inferior  qualities,  especially  of 
Madras  indigo,  it  often  rises  to  between  30  and  40  per  cent.  The  organic  portion  of  the 
indigo,  or  that  which  is  dissipated  when  indigo  is  heated,  also  consists  of  several  different 
substances. 

By  treating  indigo  with  various  solvents,  Berzclius  obtained,  besides  indigo-blue,  the 
true  coloring  matter  of  indigo,  three  other  bodies,  viz.,  indiffo-c/lnten,  indiffo-brown,  and 
indiffo-red,  which  seem  to  be  contained  in  various  proportions  in  all  kinds  of  indigo.  Indi- 
go-gluten is  obtained  by  treating  indigo  with  dilute  sulphuric,  muriatic,  or  acetic  acid,  and 
then  with  boiling  water.  It  is  left,  on  evaporation  of  its  solutions,  as  a  yellow  transparent 
extract,  which  is  soluble  in  spirits  of  wine,  and  easily  soluble  in  water,  more  difficultly  in  acid 
liquids.  Its  taste  is  like  that  of  extract  of  meat.  It  )'ields  by  dry  distillation  much  ammonia 
and  a  fetid  oil,  and  behaves  in  most  respects  like  vegetable  gluten.  On  treating  the  indigo, 
after  being  freed  from  the  indigo-gluten,  with  hot  strong  caustic  lye,  the  indigo-brown, 
together  with  a  little  indigo-blue,  dissolves,  forming  a  dark  brown,  almost  black  solution, 
from  which  the  indigo-brown,  after  filtration  from  the  portion  insoluble  in  alkali,  is  precip- 
itated by  means  of  acid.  After  being  purified,  indigo-brown  has  the  appearance  of  a  dark 
))rown  transparent  resin,  which  is  almost  tasteless  and  quite  neutral.  By  dry  distillation  it 
affords  ammonia  and  cmpyreumatic  oil.  It  is  decomposed  by  nitric  acid  and  chlorine.  It 
combines  both  with  acids  and  bases.  Its  compounds  with  alkalies  are  dark  brown,  and 
easily  soluble  in  water.  The  compound  with  baryta  is  not  easily  soluble  in  water,  and  that 
with  lime  is  insoluble.  By  boiling  the  alkaline  compounds  with  lime  in  excess,  the  indigo- 
brown   may  be   separated   and   rendered  insoluble.     The  green   substance  obtained    by 


616  INDIGO. 

Chevreul  from  indigo  seems  to  have  been  a  compound  of  indigo-bro^vn  with  ammonia 
containing  a  little  indigo-blue,  either  in  a  state  of  combination  or  mechanically  intermin- 
gled. Indigo-brown  seems  to  bear  a  great  resemblance,  in  many  of  its  properties,  to  the 
brown  resinous  substances  obtained  by  Schunck  in  the  decomposition  of  indican  with  acids. 
From  its  constant  occurrence  in  all  kinds  of  indigo,  it  may  be  inferred  that  it  is  not  a  mere 
accidental  impurity,  but  stands  in  some  unknown  relation  to  indigo-blue.  As  long,  how- 
ever, as  its  origin  and  composition  are  unknown,  this  must  remain  a  mere  supposition. 
After  the  removal  of  the  indigo-gluten  and  indigo-brown,  the  indigo  is  exhausted  with  boil- 
ing alcohol  of  specific  gravity  0-83.  A  dark  red  solution  is  obtained,  which  is  filtered  and 
distilled,  when  the  indigo-red  contained  in  it  is  deposited  as  a  blackish-brown  powder, 
which  is  quite  insoluble  both  in  water  and  in  alkaline  liquids.  Indigo-red,  according  to 
Berzelius,  is  amorphous,  but  by  distillation  in  vacuo  jields  a  white  crystalline  sublimate,  as 
well  as  unchanged  indigo-red.  Concentrated  sulphuric  acid  dissolves  it,  forming  a  dark 
yellow  solution,  which  deposits  nothing  on  being  mixed  with  water ;  the  diluted  solution  is 
rendered  colorless  by  avooI,  which  at  the  same  time  acquires  a  dirty  yellowish-brown  or  red 
color.  The  description  given  by  Berzelius  leaves  it  doubtful  whether  the  indigo-red  ob- 
tained by  him  from  indigo  was  a  pure,  unmixed  substance.  From  the  leaves  of  the  iiidigo- 
feras,  as  well  as  from  those  of  the  Isaiis  tinctoria,  a  substance  may,  according  to  Schunck, 
be  extracted,  which  has  received  from  him  the  name  of  indirxibiiie,  but  which  seems  to  be 
merely  indigo-red  in  a  state  of  purity.  This  substance  has,  according  to  Schunck,  the  fol- 
lowing j)roperties:  it  crystallizes  in  small  silky  needles  of  a  lirownish-purple  color,  which, 
when  rubbed  with  a  hard  liody,  show  a  slight  bronze-like  lustre.  When  carefully  heated  it 
may  be  entirely  volatilized,  yielding  a  yellowish-red  vapor,  which  condenses  in  the  form  of 
long  plum-colored  needles,  having  a  slight  metallic  lustre.  It  dissolves  in  concentrated 
sulphuric  acid,  forming  a  sohition  of  a  beautiful  purple  color,  which  when  diluted  with  water 
yields  no  deposit  and  then  imparts  a  fine  purple  color  to  cotton,  wool,  and  silk.  It  is  in- 
soluble in  water,  but  dissolves  in  boiling  alcohol  with  a  splendid  purple  color.  It  is  insolu- 
ble in  alkalies,  but  dissolves  when  exposed  to  the  combined  action  of  alkalies  and  reducing 
agents,  just  as  indigo-blue  does,  forming  a  solution  from  which  it  is  again  precipitated  on 
exposure  to  the  oxygen  of  the  atmosphere.  This  solution  dyes  cotton  purple.  In  most  of 
its  properties  this  body  bears  a  striking  resemblance  to  indigo-blue,  and  the  composition  of 
the  two  is  identical. 

It  has  been  doubted  whether  these  various  substances  or  impurities  with  which  indigo- 
blue  is  associated  produce  any  effect  in  the  dyeing  process  on  cotton.  In  a  memoir  by 
Schwarzenberg,  to  which  a  prize  was  awarded  by  the  Societe  Industrielle  de  Mulhouse,  the 
author  arrives  at  the  conclusion  that  neither  indigo-gluten,  indigo-brown,  nor  indigo-red 
gives  rise  to  any  appreciable  effect  when  added  to  an  indigo  vat  prepared  with  pure  indigo- 
blue.  Nevertheless  differences  are  observable  hi  dyeing  with  different  kinds  of  indigo, 
which  can  only  be  explained  on  the  supposition  that  something  besides  indigo-blue  takes 
part  in  the  process.  In  the  ordinary  blue  vat,  made  with  copperas  and  lime,  any  effect 
which  might  be  produced  in  dyeing  by  the  indigo-brown  is  neutralized  by  the  lime,  which 
forms  with  it  an  insoluble  compound.  Indigo-red,  however,  dissolves,  as  mentioned  above, 
in  contact  with  alkalies  and  reducing  agents,  and  the  solution  imparts  a  purple  color  to 
cotton.  In  the  ordinary  indigo  vat  its  presence  may  be  detected  by  precipitating  a  portion 
of  the  liquor,  and  treating  the  precipitate  with  boiling  alcohol,  which  then  usually  acquires  a 
red  color.  It  is  possible,  therefore,  that  a  small  part  of  the  effect  produced  in  dyeing  with 
indigo  may  be  due  to  indigo-red. 

That  portion  of  the  indigo  which  remains  after  treatment  with  acid,  alkali,  and  alcohol, 
consists  essentially  of  indigo-blue,  the  true  coloring  matter  of  indigo,  mixed,  however, 
with  sand,  earthy  particles,  and  other  impurities.  In  order  to  purify  it,  the  residue,  while 
still  moist,  is  to  be  mixed  with  lime,  the  quantity  of  which  must  amount  to  twice  the  weight 
of  the  crude  indigo,  and  which  has  been  previously  slaked  with  water.  The  mixture  is 
then  put  into  a  bottle  capable  of  holding  about  150  times  its  volume  of  water,  and  the 
bottle  is  filled  up  with  boiling  water  and  shaken.  A  quantity  of  finely  powdered  proto- 
sulphate  of  iron,  amounting  to  f  of  the  weight  of  the  lime  is  then  added,  the  bottle  is 
closed  with  a  stopper,  well  shaken,  and  left  to  stand  for  several  hours  in  a  warm  place. 
The  mass  gradually  becomes  green,  and  the  indigo-blue  is  then  converted  by  the  pre- 
cipitated protoxide  of  iron  into  reduced  indigo,  which  dissolves  in  the  excess  of  lime,  form- 
ing a  deep  yellow  solution.  This  solution  when  clear  is  poured  off"  from  the  deposit  into  a 
vessel  containing  a  sufficient  quantity  of  dilute  muriatic  acid  to  supersaturate  the  whole  of 
the  lime.  The  reduced  indigo,  which  is  precipitated  in  grayi.'^h-white  flocks,  is  agitated 
with  water  until  it  has  become  blue,  and  the  regenerated  indigo-blue  is  collected  on  a  filter 
and  washed  with  water,  in  order  to  remove  the  chloride  of  calcium  and  excess  of  muriatic 
acid.  The  following  method  of  obtaining  pure  indigo-blue  has  been  recommended  by 
Fritzsche  :  4  oz.  of  crude  indigo  and  the  same  weight  of  grape  sugar  are  put  into  a  bottle 
capable  of  holding  12  lbs.  of  water;  a  solution  of  (J  oz.  of  concentrated  caustic  soda  lye 
in  alcohol  is  then  added,  after  which  the  bottle  is  filled  with  hot  spirits  of  wine  of  75  per 


INDIGO.  617 

cent.,  and  the  whole  is  left  to  itself  for  some  time.  The  liquid  becomes  at  first  wine-red, 
then  yellow,  and  on  being  filtered  and  left  exposed  to  the  air,  deposits  the  indigo-blue  in 
small  crystalline  scales,  which  are  to  be  filtered  olF  and  washed  at  first  with  alcohol,  and 
then  with  water. 

Pure  indigo-blue  has  the  following  properties :  Its  color  is  dark  blue  inclining  to  purple. 
When  rubbed  with  a  hard  body  it  assumes  a  bright  coppery  lustre.  It  has  neither  taste 
nor  smell,  possesses  neither  acid  nor  basic  properties,  and  belongs,  as  regards  its  chemical 
alBnities,  to  the  class  of  indifferent  substances.  Its  specific  gmvity  is  l"oO.  When  heated 
in  the  open  air  it  melts,  boils,  and  burns  with  a  smoky  flame,  leaving  a  carbonaceous  residue. 
But  when  it  is  heated  in  a  vessel  partially  closed,  or  in  vacuo,  it  begins  to  evolve  at  a  tem- 
perature of  about  550°  F.  a  violet-colored  vapor,  which  condenses  on  the  colder  parts  of 
the  apparatus  in  the  form  of  long  crystalline  needles,  which  are  blue  by  transmitted  light, 
but  exlii  jit  by  reflected  light  a  beautiful  coppery  lustre.  These  needles  are  unchanged 
indigo-blue.  A  great  portion  of  the  indigo-blue  i.s,  however,  decomposed  during  the  heating 
process.  Indigo-blue  is  insoluble  in  water,  alkalies,  and  dilute  acids.  Boiling  alcohol  and 
'  boiling  oil  of  turpentine  dissolve  a  minute  quantity  of  it,  and  deposit  it  again  on  cooling. 
Fixed  oils  also  dissolve  a  little  of  it  at  a  heat  exceeding  that  of  boiling  water,  yielding  blue 
solutions,  the  color  of  which,  when  the  heat  is  further  increased,  changes,  according  to 
Mr.  Crum,  first  to  crimson  and  then  to  orange.  By  the  action  of  dilute  nitric  and  chromic 
acids  indigo-blue  is  decomposed  and  converted  into  isati?ie,  a  body  soluble  in  water  and 
crystallizing  in  red  needles.  Cldorine  also  decomposes  indigo-blue,  changing  it  into  chlori- 
sit-ine,  a  substance  having  properties  very  similar  to  those  of  isatine.  Both  isatinc  and 
chlorisatine  afford  with  different  reagents  a  great  number  of  products  of  decomposition, 
none  of  which  have,  however,  as  yet  found  any  application  in  the  arts.  By  the  long  con- 
tinued action  of  boiling  nitric  acid  indigo-blue  is  converted,  first  into  indicfotic  acid,  a  v^iite 
crystalline  acid,  and  then  into  nitropicric  acid,  which  is  yellow  and  crystallized.  The  latter 
is  sometimes  employed  for  imparting  a  yellow  color  to  silk  and  wool,  but  it  is  generally 
prepared  from  cheaper  materials  than  indigo-blue.  The  action  of  concentrated  sulphuric 
acid  on  indigo-blue  is  very  remarkable.  When  the  acid  is  poured  on  the  pure  substance 
and  gently  heated  it  acquires  in  the  first  instance  a  green  color,  which  changes  after  some 
time  to  blue.  No  gas  of  any  kind  is  evolved.  When,  however,  crude  indigo  is  employed, 
there  is  a  perceptible  disengagement  of  sulphurous  acid,  resulting  from  the  action  of  the 
sulphuric  acid  on  the  impurities  of  the  indigo,  such  as  the  indigo-gluten,  kc.  On  adding 
water,  a  solution  of  a  beautiful  deep  blue  color  is  obtained.  The  filtered  liquid  contains  a 
peculiar  acid,  to  which  the  names  of  indigo-sulphuric,  snlpjhindigotic,  sulphindylic,  or 
ccendeo-sulphiiric  acid  have  been  applied. 

This  acid  is  a  so-called  double  acid.  It  contains  indigo-blue  and  sulphuric  acid,  but  in 
such  a  peculiar  state  of  combination  that  neither  of  the  two  constituents  can  be  detected 
by  ordinary  reagents,  nor  again  eliminated  as  such  from  the  compound.  It  combines  with 
bases,  without  either  of  the  two  constituents  separating.  The  compounds  are  called  indigo- 
sulphatex,  and  are,  like  the  acid,  of  a  dark  blue  color.  When  the  solution  of  indigo-blue 
in  concentrated  sulphuric  acid  is  diluted  with  water,  there  is  usually  formed  a  small  quan- 
tity of  a  dark  blue  flocculent  precipitate, which  is  the  phcnicine  of  Mr.  Crum,  or  the  indir/o- 
purple  of  Barzelius.  It  is  a  compound  of  indigo-blue  with  sulphuric  acid,  containing  less 
of  the  latter  than  indigo-sulphuric  acid.  It  is  always  formed  when  the  quantity  of  sulphuric 
acid  employed  is  not  more  than  eight  times  that  of  the  indigo-blue,  or  when  the  action  of 
the  acid  on  the  latter  has  continued  for  only  a  short  time.  By  heating  it  with  an  excess  of 
acid  it  is  changed  into  indigo-sulphuric  acid.  Though  soluble  in  concentrated  sulphuric 
acid,  it  is  insoluble  in  the  dilute  acid,  and  hence  is  precipitated  on  the  addition  of  water. 
On  filtering  and  washing,  however,  it  begins  to  dis%olve  as  soon  as  the  free  sulphuric  acid 
has  been  removed,  and  may  then  be  completely  dissolved  by  pure  water.  The  solution  has 
a  blue  color,  just  like  that  of  indigo-sulphuric  acid.  Its  compounds  with  bases  have  a  blue 
color  with  a  purplish  tinge.  The  blue  acid  liquid  filtered  from  the  indigo-purple,  on  being 
suj)ersaturated  with  carbonate  of  potash  or  soda,  deposits  a  dark  blue  powder,  which  con- 
sists of  the  indigo-sulphate  of  potash  or  soda.  These  compounds  are  iusolulde  in  water 
containing  a  large  (luantity  of  neutral  salts,  and  are  therefore  precipitated  when  the  excess 
of  sulphuric  acid  is  neutralized  by  carbonate  of  potash  or  soda.  As  soon,  however,  as  the 
sulphate  of  potash  or  soda  has  been  removed  by  washing,  the  indigo-sulphate  may  be  dis- 
solved m  pure  water,  yielding  a  dark  blue  solution.  The  indigo-sulphates  of  the  alkalies 
may  also  be  prepared  by  steeping  wool,  i)reviously  well  cleaned,  into  the  solution  in  sul- 
phuric acid.  The  wool  takes  up  the  color,  becoming  of  a  dark  blue  color,  and  after  having 
been  well  washed  with  (vater,  in  order  to  remove  the  excess  of  acid  as  well  as  the  impurities 
which  are  always  present  in  the  solution  when  crude  indigo  has  been  employed,  is  treated 
with  carbonate  of  potash,  soda,  or  ammonia,  which  separate  the  acid  from  the  wool,  and 
produce  blue  solutions  conUiining  the  salts  of  the  rcs])ective  bases.  The  indigo-sulpliates 
of  t'ne  earths  and  metallic  oxides,  which  are  mostly  insoluble  blue  powders,  may  be  obtained 
from  the  alkaline  salts  by  double  decomposition.     By  an  excess  of  caustic  alkali,  indigo- 


618  INDIGO. 

sulphuric  acid  is  immediately  decomposed,  giving  a  yellow  solution,  from  wliich  it  is  im- 
possible to  obtain  the  acid  agaiij.  By  means  of  reducing  agents,  such  as  sulphuretted  hydro- 
gen, nascent  hj'drogen,  protosalts  of  tin  and  iron,  &c.,  indigo-sulphuric  acid  is  decolorized, 
but  the  color  is  restored  by  the  oxygen  of  the  atmosphere.  Indigo-sulphuric  acid,  iu  a  free 
state  or  in  combination  with  alkalies,  is  employed  in  the  arts  for  the  purpose  of  imparting  a 
blue  color  to  silk  and  wool.  It  has  very  little  affinity  for  cotton  fibre,  but  is  nevertheless 
employed  occasionally  for  blueing  white  cotton-yarn  and  other  bleached  goods. 

By  treatment  with  strong  boiling  caustic  potash  or  soda  lye,  indigo-blue  is  gradually  de- 
composed and  converted  into  a  colorless  crystallized  acid,  anthranilic  acid.  By  weak  solu- 
tions of  cau.stic  alkalies,  it  is  not  in  the  least  affected.  If,  however,  it  be  subjected  to  the 
combined  action  of  an  alkali  or  alkaline  earth  and  some  body  having  a  strong  affinity  for 
oxygen,  such  as  protoxide  of  iron  or  tin,  sulphur,  sulphurous  or  phosphorous  aciil,  or 
organic  matters,  such  as  grape-sugar,  &c.,  it  disappears  by  degrees,  yielding  a  yellow  solution, 
containing  in  the  place  of  indigo-blue  another  substance,  which  has  been  called  iiidigo-uhite, 
indigogene,  or  reduced  indiyo.  When  an  excess  of  some  acid  is  added  to  the  yellow  solu- 
tion, the  indigo-white  is  precipitated  in  white  or  grayish-white  flocks,  which  on  filtration 
and  exposure  to  the  atmosphere  rapidly  become  blue,  and  are  reconverted  into  indigo-blue. 
Indigo-white  is  insoluble  in  water,  but  slightly  soluble  in  alcohol.  It  is  soluble  in  caustic 
alkalies,  lime,  and  baryta  water.  The  solutions,  on  exposure  to  oxygen,  become  covered  with 
a  pellicle  of  regenerated  indigo-blue.  With  an  excess  of  lime  it  gives  an  insoluble  com- 
pound. Its  compounds  with  alumina  and  metallic  oxides,  which  are  insoluble  in  water,  may 
be  obtained  by  double  decomposition.  Salts  of  oxide  of  copper,  when  added  to  its  solu- 
tions in  alkali,  convert  it  immediately  into  indigo-blue,  the  oxide  of  copper  being  reduced  to 
suboxide.  Indigo-blue  is  also  converted  into  indigo-white  when  it  is  exposed  to  the  action 
of  fermenting  or  putrefying  substances,  in  the  presence  of  water.  Here  the  decomposing 
organic  matter  is  the  reducing  agent,  and  ammonia,  which  is  usually  formed  during  the 
process  of  putrefaction,  is  the  solvent  of  the  indigo-white.  If  a  piece  of  cotton,  wool,  or 
silk  be  dipped  into  an  alkaline  solution  of  indigo-white  and  then  exposed  to  the  atmos- 
phere, it  acquires  a  blue  color,  which  may  be  made  deeper  by  repeated  dippings  and  sub- 
sequent exposure.  It  is  on  this  property  of  indigo-white  that  the  dyeing  with  indigo 
depends. 

The  true  chemical  formula  of  indigo-blue,  which  was  first  discovered  by  Mr.  Crum,  is 
CH'NO",  and  100  parts  contain  therefore  by  calculation  '73"28  carbon,  3'81  hydrogen, 
10'68  nitrogen,  and  12-23  oxygen.  The  formula  of  indigo-white  is  C^IFNO",  and  it  differs 
therefore  from  indigo-blue  by  containing  1  atom  more  of  hydrogen,  which  is  taken  up 
during  the  so-called  reduction  of  the  latter,  and  lost  again  by  oxidation  during  its  reconver- 
sion into  indigo-blue. 

Since  the  value  of  indigo  depends  entirely  on  the  quantity  of  indigo-blue  which  it  con- 
tains, it  is  of  great  importance  to  ascertain  the  exact  amount  of  the  latter  in  any  given 
sample  of  the  article.  Before  commencing  the  determination  of  the  indigo-blue,  a  weighed 
portion  of  the  indigo  ought  to  be  heated  for  some  hours  at  212°  F.,  and  then  weighed 
again.  The  loss  in  weight  which  takes  place  represents  the  amount  of  water  contained  in 
the  sample.  A  weighed  quantity  of  the  dried  indigo  is  then  to  be  heated  over  the  flame 
of  a  lamp  until  all  the  organic  matter  has  been  burnt  away.  By  weighing  the  residue 
which  is  left  the  amount  of  ash  or  inorganic  matter  is  ascertained.  In  order,  in  the  next 
place,  to  determine  the  amount  of  indigo-blue,  several  methods  have  been  devised  by 
various  chemists,  none  of  which,  however,  yield  very  accurate  results.  Of  these  methods 
the  following  are  the  princii)al  ones  : — 

1.  A  weighed  quantity  of  finely  pounded  indigo  is  ruljbed  with  water  in  a  porcelain 
mortar.  An  equal  weight  of  pure  lime  is  then  slaked  with  water,  and  the  hydrate  is  well 
mixed  with  the  indigo.  The  mixture  is  then  poured  into  a  stoppered  bottle  of  known 
cajjacity,  and  the  mortar  is  well  rinsed  with  water,  which  is  added  to  the  rest.  The  bottle 
is  now  heated  in  a  water-bath  for  several  hours,  and  a  ([uantity  of  finely  pounded  sulphate 
of  iron  is  added  ;  the  bottle  is  then  filled  up  with  water,  the  .stopper  is  inserted,  and  after 
the  contents  have  been  well  shaken  the  whole  is  allowed  to  repose  for  some  hours,  until  the 
indigo  has  been  reduced  and  the  sediment  has  sunk  to  the  bottom.  A  portion  of  the  clear 
liquor  is  then  drawn  off  with  a  siphon,  and  the  (piantity  of  li(iuid  having  been  accurately 
measured,  it  is  mixed  with  an  excess  of  muriatic  acid,  and  tlie  precipitate,  after  having 
been  oxidized,  is  collected  on  a  weighed  filter  and  well  washed  with  water.  Lastly,  the 
filter  with  the  indigo-blue  is  dried  at  212'  F.  and  weighed,  and  the  weight  of  the  filter  hav- 
ing been  subtracted  from  that  of  the  whole,  the  weight  of  the  indigo-blue  is  ascertained. 
Supposing  now  that  the  whole  quantity  of  liquid  had  been  200  measures,  that  50  measures 
had  been  drawn  off  yielding  10  grains  of  indigo-blue,  then  the  sample  contained  on  the 
whole  40  grains  of  the  latter.  For  60  grains  of  indigo  it  is  necessary  to  take  from  1  lb.  to 
2  lbs.  of  water. 

According  to  Mr.  John  Dale,  of  Manchester,  who  has  had  great  experience  in  the  valua- 
tion of  indigo  for  practical  purposes,  tlris  method,  though  rather  long  and  tedious,  still 


INDIGO.  019 

gives  more  accurate  results  than  any  other.  The  quantity  of  indigo-blue  indicated  by  it  is 
generally  below  the  actual  quantity  contained  in  the  sample.  According  to  Berzelius  this 
loss  arises  from  the  lime  forming  an  insoluble  compound  with  a  portion  of  the  reduced  indigo- 
blue.  Mr.  Dale,  however,  is  of  opinion,  that  even  when  every  precaution  has  been  taken, 
a  certain  loss,  proceeding  from  some  hitherto  unascertained  cause,  cannot  be  avoided. 
When,  for  instance,  pure  indigo-blue  is  treated  with  lime  and  copperas  in  the  manner  just 
described,  the  quantity  which  is  again  obtained  by  precipitation  from  any  portion  of  the 
liquid  is  always  less  than  what  it  should  be  by  calculation,  even  when  no  excess  of  lime  has 
been  employed. 

2.  The  second  method  of  determining  the  indigo-blue  is  performed  as  follows  : — About 
15  or  20  grains  of  pure  indigo-blue,  obtained  by  precipitation  from  an  indigo  vat,  and  the 
same  quantity  of  the  indigo  to  be  tested,  which  must  be  previously  ground  to  a  fine  powder, 
are  weighed  off,  and  each  of  them  is  treated  with  about  12  times  its  weight  of  concentrated 
sulphuric  acid  in  a  flask  or  porcelain  basin.  After  being  heated  at  a  temperature  of  120' 
to  140"  F.  for  about  24  hours,  and  occasionally  well  agitated,  the  two  liquids  are  mixed 
with  water,  so  that  the  volume  of  the  two  shall  be  exactly  equal.  Two  equal  measures 
of  a  weak  solution  of  hypochlorite  of  lime  are  then  taken,  and  to  the  first  is  added  a  quan- 
tity of  the  solution  of  pure  indigo.  The  chlorine  liberated  by  the  excess  of  sulphuric  acid 
in  the  solution  destroys  the  blue  color  of  the  indigo-sulphuric  acid.  More  of  the  solution 
must  be  added  until  the  liquid  begins  to  acquire  a  greenish  tinge,  and  the  number  of 
measures  necessary  for  the  purpose  is  noted.  The  same  experiment  is  then  made  with  the 
solution  of  crude  indigo.  The  quantity  of  indigo-blue  in  the  latter  is,  of  course,  in  inverse 
ratio  to  the  number  of  measures  which  are  requisite  in  order  to  take  up  the  whole  of  the 
chlorine  which  is  liberated.  If,  for  example,  the  same  quantity  of  hypochlorite  of  lime 
decolorizes  167  measures  of  the  solution  of  pure  indigo-blue  and  204  measures  of  the  solu- 
tion of  crude  indigo,  then  the  quantity  of  indigo-blue  contained  in  100  parts  of  the  latter  is 
given  by  the  following  proportion — 204  :  167  : :  100  :  x  =  SrS. 

A  number  of  samples  of  indigo  may  be  tested  in  this  manner  at  the  same  time.  Care 
must  be  taken  to  prepare  a  fresh  solution  of  indigo-blue  for  every  series  of  trials,  since  this 
solution  undergoes  a  change  on  standing,  which  renders  it  quite  inapplicable  as  a  standard 
of  comparison.  It  is  necessary  also  to  pay  great  attention  at  the  moment  when  the  green- 
ish color  indicating  an  excess  of  the  sulphate  of  indigo  begins  to  appear,  for  it  will  often  be 
found  that  this  color  disappears  after  standing  a  few  minutes,  and  a  fresh  quantity  of  the 
blue  solution  must  then  be  added  cautiously,  until  the  greenish  tinge  becomes  permanent, 
even  after  standing  for  some  time.  Modifications  of  this  process  have  been  introduced  by 
various  chemists  by  the  use  of  permanganate  of  potash,  chlorate  of  potash,  or  bichromate 
of  potash,  in  the  place  of  hypochlorite  of  lime  :  but  as  the  principle  on  which  the  process 
depends  is  in  each  case  identical  and  the  modus  operandi  is  almost  the  same,  it  will  be  un- 
necessary to  enter  into  any  minute  description  of  these  modifications.  The  whole  method 
is,  l>owever,  open  to  serious  objections,  and  the  results  which  it  affords  cannot  at  all  be  de- 
pended on.  In  the  first  place,  it  is  difficult  to  institute  a  strict  comparison  between  the 
dilFerent  shades  of  color  resulting  from  the  decomposition  of  the  sulphate  of  indigo  in  dif- 
ferent cases,  since  the  pure  green  tinge  observed  when  an  excess  of  the  pure  sulphate  has 
been  added  to  the  decomposing  agent,  gives  place  to  a  dirty  olive  or  Ijrownish-green,  when 
a  solution  of  crude  indigo  is  employed,  in  consequence  of  the  impurities  contained  in  the 
latter.  Secondly,  it  is  almost  impossible  to  avoid  tlie  formation  of  a  certain  quantity  of 
sulphurous  acid  during  the  action  of  concentrated  sulphuric  acid  on  crude  indigo.  This 
sulphurous  acid  during  the  following  operation  becomes  oxidized  before  the  blue  sulphate 
is  destroyed,  and  hence  the  percentage  of  indigo-blue  is  apparently  raised.  In  employing 
this  method,  it  is  common  to  find  more  than  80  per  cent,  of  indigo-blue  in  a  good  sample 
of  indigo,  whereas  the  best  qualities  seldom  contain  above  60  per  cent.,  and  average  quali- 
ties between  40  and  50  per  cent.  This  method  may  show  a  percentage  of  70  indigo-blue, 
when  the  method  first  described  indicates  between  50  and  60. 

3.  The  third  method  of  estimating  the  indigo-blue  is  performed  in  the  following  manner : 
Equal  weights  of  the  samples  to  be  tested  are  treated  with  equal  quantities  of  concentrated 
sulphuric  acid  in  the  manner  above  described,  and  the  solutions  are  then  diluted  with  water 
and  introduced  into  graduated  glass  cylinders,  water  being  added  to  each  until  they  all 
exhibit  exactly  the  same  shade  of  color.  The  richer  the  sample  is  in  indigo-blue,  the 
greater  will  be  the  quantity  of  water  necessary  for  this  ])urpose,  the  number  of  measures 
of  water  required  in  each  ca.se  indicating  the  relative  amount.  The  great  objection  to  this 
method  consists  in  the  circumstance,  that  the  different  kinds  of  indigo  do  not  give  the  same 
shade  of  blue  when  their  solutions  in  sulphuric  acid  are  diluted  with  water,  some  exhibiting 
a  pure  blue  color,  others  a  blue  with  a  greenish  or  purplish  tinge.  It  tliereforc  becomes 
difficult  to  institute  an  exact  comparison  between  them. 

The  ingredients  necessary  for  setting  the  vat  are  copperas  or  protosulphate  of  iron, 
newly  slaked  quicklime,  and  water.  Various  proportions  of  these  ingredients  are  employed, 
as  for  instance,  1  part  by  weight  of  indigo,  (dry,)  3  parts  of  copperas,  and  4  of  lime ;  or  1 


620  INDIGO. 

of  indigo,  2^  of  copperas,  and  3  of  lime ;  or  8  of  indigo,  14  of  copperas,  and  20  of  lime ; 
or  1  of  indigo,  f  of  copperas,  and  1  of  lime.  The  sulphate  of  iron  should  be  as  free  as 
possible  from  the  red  oxide  of  iron,  as  well  as  from  sulphate  of  copper,  which  would  re- 
oxidize  the  reduced  indigo-blue.  The  vat  having  been  filled  with  water  to  near  the  top,  the 
materials  are  introduced,  and  the  whole  after  being  well  stirred  several  times  is  left  to  stand 
for  about  twelve  hours.  The  chemical  action  which  takes  ])l:ice  is  very  simple.  The 
protoxide  of  iron  which  is  set  at  liberty  by  the  lime  reduces  the  indigo-l^lue,  and  the  indigo- 
white  is  then  dissolved  by  the  excess  of  lime,  forming  a  solution,  which,  on  being  examined 
in  a  glas.s,  appears  perfectly  transparent  and  of  a  pure  yellow  cokr,  and  becomes  covered 
wherever  it  comes  into  contact  with  the  air,  with  a  copper-colored  pellicle  of  regenerated 
indigo-l)luc.  The  sediment  at  the  bottom  of  the  vat  consists  of  sulphate  of  lime,  peroxide 
of  iron,  and  the  insoluble  impurities  of  the  indigo,  such  as  indigo-brown  in  combination 
with  lime,  as  well  as  sand,  clay,  &c.  If  an  excess  of  lime  is  present,  a  little  reduced  indigo- 
blue  will  also  be  found  in  the  sediment  in  combination  with  lime. 

The  copperas  vat  is  employed  in  dyeing  cotton,  linen,  and  silk.  For  cotton  goods  no 
other  kind  of  vat  is  used  at  the  present  day.  The  dyeing  process  itself  is  very  simple. 
The  vat  having  been  allowed  to  settle,  the  goods  are  plunged  into  the  clear  liquor,  and  after 
being  gently  moved  about  in  it  for  some  time  are  taken  out,  allowed  to  drain,  and  exposed 
to  the  action  of  the  atmosphere.  Whilst  in  the  liquid  the  fabric  attracts  a  portion  of  the 
reduced  indigo-blue.  On  now  removing  it  from  the  Tuiuid  it  appears  green,  but  soon  be- 
comes blue  on  exposure  to  the  air  in  consequence  of  tlie  oxidation  of  the  reduced  indigo- 
blue.  On  again  plunging  it  into  the  vat,  the  deoxidizing  action  of  the  latter  does  not  again 
remove  the  indigo-blue  which  has  been  deposited  within  and  around  the  vegetable  or  animal 
fibre,  but  on  the  contrary,  a  fresh  portion  of  reduced  indigo-l)lue  is  attracted,  which  on  re- 
moval from  the  liquid  is  again  oxidized  like  the  first,  and  the  color  thus  becomes  a  shade 
darker.  By  repeating  this  process  several  times,  the  requisite  depth  of  color  is  attained. 
This  efiect  cannot  in  any  case  be  produced  by  one  immersion  in  the  vat,  however  strong  it 
may  be.  The  beauty  of  the  <folor  is  increased  by  finall}'  passing  the  goods  through  diluted 
sulphuric  or  muriatic  acid,  which  removes  the  adhering  lime  and  oxide  of  iron.  After  being 
used  for  some  time  the  vat  sliould  be  refreshed  or  fed  with  copperas  and  lime,  upon  which 
occasion  the  sediment  must  first  be  stirred  up,  and  then  allowed  to  settle  again,  so  as  to  leave 
the  liquor  clear.  Tlie  indigo-l)lue,  however,  is  in  course  of  time  gradually  removed,  and  by 
degrees  the  vat  becomes  capable  of  dyeing  only  pale  shades  of  blue.  When  the  color  produced 
by  it  is  only  very  faint,  it  is  no  longer  worth  while  using  it,  and  the  contents  are  then  thrown 
away.  In  dyeing  cotton  with  indigo,  it  seems  to  be  essential  that  the  reduced  indigo-blue 
should  be  in  coml)ination  with  lime.  If  potash  or  soda  be  used  in  its  stead,  it  is  impossible 
to  obtain  dark  shades  of  blue. 

When  cotton  piece  goods  are  to  be  dyed  of  a  uniform  blue,  they  are  not  submitted  to 
any  preparatory  process  of  bleaching  or  washing.  Indeed  the  size  contained  in  unbleached 
goods  seems  rather  to  facilitate  than  to  impede  the  dyeing  process.  In  dyeing  these  goods 
a  peculiar  roller  apparatus  is  employed.  When  certain  portions  of  the  fabiic  are  to  retain 
their  white  color  a  difierent  plan  is  adopted.  The  pieces  having  been  bleached,  those  por- 
tions which  arc  to  remain  white  are  printed  with  so-called  resists.  These  resists  consist 
essentially  of  some  salt  of  copper,  mixed  with  an  appropriate  thickening  material.  The 
copper  salt  acts  by  oxidizing  the  reduced  indigo-blue  at  the  surface,  and  thus  rendering  it 
insoluble  before  it  can  enter  the  interior  of  the  vegetable  fibre,  since  it  is  only  when  de- 
posited within  the  fibre  itself  that  the  coloring  matter  becomes  durably  fixed.  The  pieces  are 
now  stretched  upon  square  dipping  frames,  made  of  wood  or  of  iron,  furnished  with  sharp 
hooks  or  points  of  attachment.  These  frames  are  suspended  by  cords  over  a  pulley,  and  thus 
immersed  and  lifted  out  alternately  at  proper  intervals.  In  dyeing,  a  set  of  10  vats  is  used, 
the  first  vat  containing  5  or  G  lbs.  of  indigo,  and  the  quantity  increasing  gradually  up  to  80  lbs. 
in  the  last  vat.  The  pieces  are  dipped  for  7^  minutes  in  tiie  first  vat,  then  taken  out  and  ex- 
posed to  the  air  for  the  same  length  of  time,  then  dippetl  in  the  second  vat,  and  so  on  to  the  last. 
After  passing  through  the  hist  vat,  a  small  bit  of  the  calico  is  dried,  in  order  to  see  whether 
the  color  is  sufficiently  dark.  If  it  is  not,  the  whole  series  must  be  dipped  once  more  in  the 
same  vat  in  which  the  last  dipping  was  performed.  When  the  bottom  of  the  vat  is  raked 
up  so  as  to  have  more  lime  in  suspension,  the  vat  becomes  what  the  dyer  calls  hard,  that  is 
to  say,  the  oxide  of  copper  of  the  resist  is  precipitated  in  a  compact  state,  and  consequently 
acts  with  more  efficiency.  But  when  the  vat  has  Vjeen  at  rest  for  some  time,  and  there  is 
little  lime  in  suspension,  then  it  is  called  soft.  When  it  is  in  this  state,  the  oxide  of  copper 
is  thrown  down  in  a  bulky  form,  and  when  the  pieces  are  afterwards  agitated  in  the  liqui  r, 
in  order  to  detach  the  oxide  of  iron,  which  always  floats  about  in  the  vat,  and  attach.es 
itself  to  the  fabric,  and  which  if  left  adhering  would  cause  light  stains,  technically  called 
[froiaidhicj  ;  then  the  oxide  of  copper  is  also  detached,  and  the  indigo  penetrates  to  those 
parts  which  are  to  remain  white.  When  cotton  yarn  is  dyed  in  the  copperas  vat,  the  latter 
is  generally  heated  by  means  of  steam  pipes  passing  through  the  liquor,  the  object  being  to 
give  to  the  color  tlie  peculiar  gloss  or  lustre,  which  is  required  in  this  class  of  goods.     No 


INDIGO.  621 

preparatory  process  is  required,  except  simply  steeping  in  hot  water.  In  dyeing,  wooden 
pins  are  put  through  the  hanks,  their  ends  resting  on  supports  passing  over  the  top  of  the 
vat,  and  the  yarn  is  then  slowly  turned  over,  one  half  being  iu  the  liquor,  the  other  half 
over  the  pins.  It  is  then  taken  out,  wrung,  exposed  to  the  air,  and  again  dipped,  this 
operation  being  repeated  until  the  requisite  shade  is  obtained. 

The  methods  employed  for  producing  the  colors  called  China  blue  and  pencil  blue  on 
calico  have  been  described  under  Calico  Printing. 

Woad  vat. — In  former  times,  woad  was  the  only  material  known  to  the  dyers  of  Europe 
for  producing  the  blue  color  of  indigo.  For  this  purpose  it  was  previously  submitted  to  a 
peculiar  process  of  fermentation,  and  the  product  was  named  pastel  in  France.  For  most 
purposes  indigo  has  taken  the  place  of  woad  in  the  dye-house,  and  for  cotton  goods  it  is 
now  used  alone.  In  the  dyeing  of  woollen  goods,  however,  the  use  of  woad  has  been  re- 
tained to  the  present  day,  for  the  purpose  rather  of  exciting  fermentation  and  thus  reducing 
the  indigo  which  is  employed  at  the  same  time,  than  of  imparting  any  color  to  the  material 
to  be  dyed.  Indeed,  the  woad  used  by  woollen  dyers  in  this  country  contains  no  trace  of 
coloring  matter.  Various  substitutes,  such  as  rhubarb  leaves,  turnip  tops,  weld,  and  other 
vegetable  matters,  have  accordingly  been  tried,  but  without  success,  since  the  fermentation 
is  more  readily  maintained  by  means  of  woad  than  by  any  other  material.  Pastel,  which 
does  contain  a  little  blue  coloring  matter,  is  preferred  to  woad  by  many  of  the  French  dyers. 
The  materials  employed  in  the  ordinary  woad  or  pastel  vat,  in  addition  to  woad  and  indigo, 
are  madder,  bran,  and  lime.  In  the  so-called  Indian  or  potash  vat,  madder,  bran,  and  car- 
bonate of  potash  are  used ;  in  the  German  vat,  bran,  carbonate  of  soda,  and  quicklime, 
without  woad.  The  chemical  action  which  takes  place  in  the  woad  vat  is  not  difficult  to 
understand.  The  nitrogenous  matters  of  the  woad  begin,  when  the  temperature  is  raised, 
to  eater  into  a  state  of  fermentation,  which  is  kept  up  by  means  of  the  sugar,  starch,  ex- 
tractive matter,  &c.,  of  the  madder  and  bran.  In  consequence  of  the  fermentation,  the 
indigo-blue  becomes  reduced,  and  is  then  dissolved  by  the  lime,  thus  rendering  the  liquid 
fit  for  dyeing.  Great  care  is  necessary  in  order  to  prevent  the  process  of  fermentation 
from  passing  into  one  of  putrefaction,  which  if  allowed  to  proceed  would  lead  to  the  entire 
destruction  of  the  indigo-blue  in  the  liquor.  If  any  tendency  to  do  so  is  observed,  it  is 
arrested  by  the  addition  of  lime,  which  combines  with  the  acetic,  lactic,  and  other  organic 
acids  that  commence  to  form  when  putrefaction  sets  in.  On  the  other  hand,  an  excess  of 
lime  must  also  be  avoided,  since  the  reduced  indigo-blue  is  thereby  rendered  insoluble,  and 
unfit  to  combine  with  the  material. 

The  following  account  of  the  method  of  d3'eing  woollen  goods  with  indigo,  as  carried  on 
at  present  in  Yorkshire,  may  suffice  to  give  a  general  idea  of  the  process : — 

The  dye-vats  employed  are  circular,  having  a  diameter  of  6  feet  6  inches,  and  a  depth 
of  7  feet,  and  ai-e  made  of  cast  iron  f  of  an  inch  in  thickness.  They  are  surrounded  by 
brickwork,  a  space  of  3  inches  in  width  being  left  between  the  brickwork  and  the  iron,  for 
the  purpose  of  admitting  steam,  by  means  of  which  the  vats  are  heated.  The  interior  sur- 
face of  the  brickwork  is  well  cemented.  In  setting  a  vat  the  following  materials  are  used : 
5  cwt.  of  woad,  30  lbs.  of  indigo,  56  lbs.  of  bran,  7  lbs.  of  madder,  and  10  quarts  of  lime. 
The  woad  supplied  to  the  Yorkshire  dyers  is  grown  and  prepared  in  Lincolnshire.  It  is  in 
the  form  of  a  thick  brownish-yellow  paste,  having  a  strong  ammoniacal  smell.  The  indigo 
is  ground  with  water  in  the  usual  manner.  The  madder  acts  in  promoting  fermentation, 
but  it  also  serves  to  give  a  reddish  tinge  to  the  color.  The  lime  is  prepared  by  putting  quick- 
lime into  a  basket,  then  dipping  it  iu  water  for  an  instant,  lifting  it  out  again,  and  then  passing 
it  through  a  sieve,  l)y  which  means  it  is  reduced  to  a  fine  powder,  called  by  the  dyers  v:are. 
The  vat  is  first  filled  with  water,  which  is  heated  to  140''  Fahr.,  after  which  the  materials 
are  put  in,  and  the  whole  is  well  stirred  until  the  woad  is  dissolved  or  diffused,  and  it  is 
then  left  to  stand  undisturbed  over  night.  At  6  o'clock  the  next  mornuig  the  liijuor  is 
again  stirred  up,  and  5  quarts  more  lime  are  added.  At  10  o'clock,  5  pints  of  lime  are 
again  thrown  in,  and  at  \'l  o'clock  the  heat  is  raised  to  120"  I'ahr.,  which  temiierature  nnist 
be  kept  up  until  3  o'clock,  when  another  quart  of  lime  is  introduced.  The  vat  is  now  ready 
for  dyeing.  "Wlicn  the  process  of  fermentation  is  proceeding  in  a  regular  manner,  the 
lifiuid,  thougli  iiuiddy  from  insoluble  vegetable  matter  in  suspension,  is  of  a  yellow  or  olivc- 
ycUow  color ;  its  surface  is  covered  with  a  blue  froth  or  a  copper-colored  pellicle,  and  it 
exhales  a  peculiar  ammoniacal  odor ;  at  the  bottom  of  the  vat  there  is  a  mass  of  undissolved 
matter,  of  a  dirty  yellow  color.  If  there  is  an  excess  of  lime  present,  the  rnpior  has  a 
dark  green  color,  and  is  covered  with  a  grayish  film,  and  when  agitated,  the  bubliles  which 
are  formed  agglomerate  on  the  surfiice,  and  are  not  easily  broken.  Clotli  dyed  in  a  li((Uor 
of  this  kind  loses  its  color  on  being  washed.  This  state  of  the  vat  is  remedied  by  the  addi- 
tion of  l)ran,  and  is  of  no  serious  consequence.  When,  on  the  other  hand,  there  is  a  de- 
ficiency of  lime,  or  in  other  words,  wlien  the  fermentation  is  too  active,  tlic  li<iuor  acquires 
first  a  drab,  then  a  clay-like  color;  wlien  agitutud,  the  bul)bles  which  form  on  its  surface 
burst  easily,  and  when  stirred  up  from  the  bottom  with  a  rake  it  eifervesces  slightly,  ov  frets, 
as  the  dyers  say.     If  the  fermentation  be  not  checked  at  this  stage,  putrefaction  soon  sets 


622  IODINE. 

in,  the  liquid  begins  to  exhale  a  fetid  odor,  and  when  stirred  evolves  large  quantities  of 
gas,  which  burn  with  a  blue  flame  on  the  application  of  a  light.  The  indigo  is  now  totally 
destroyed,  and  the  contents  of  the  vat  may  be  thrown  away.  No  further  addition  of  woad 
is  required  after  the  introduction  of  the  quantity  taken  in  first  setting  the  vat,  the  fermen- 
tation being  kept  up  by  adding  daily  about  4  lbs.  of  bran,  together  with  1  quart  or  3  pints 
of  lime.  Indigo  is  also  added  daily  for  about  thre^or  four  months.  The  vat  is  then  used 
for  the  purpose  of  dyeing  light  shades,  until  the  indigo  contained  in  it  is  quite  exhausted, 
and  its  contents  are  then  thrown  away. 

Woollen  cloth,  before  being  dyed,  is  boiled  in  water  for  one  hour,  then  passed  imme- 
diately into  cold  water.  If  it  be  suffered  to  lie  in  heaps  immediately  after  being  boiled,  it 
undergoes  some  change,  which  renders  it  afterwards  incapable  of  taking  up  color  in  the 
vat.  When  a  purple  bloom  is  required  on  the  cloth,  it  is  dyed  with  cudbear  to  a  light 
purple  shade  before  being  dipped.  In  dyeing,  the  cloth  is  placed  on  a  network  of  rope  at- 
tached to  an  iron  ring,  which  is  suspended  by  four  iron  chains  at  a  depth  of  about  3  feet 
beneath  the  surface  of  the  liquor.  The  cloth  is  stirred  about  in  the  liquor  by  means  of 
hooks  for  about  20  or  30  minutes.  It  is  then  taken  out  and  well  Avrung.  It  now  appears 
green,  but  on  being  unfolded  and  exposed  to  the  air  rapidly  becomes  blue.  When  the  vat 
contains  an  excess  of  lime  the  cloth  has  a  dark  green  color  when  taken  out.  It  is  then 
passed  through  hot  water  and  dipped  again,  if  a  darker  shade  is  required.  When  woollen 
flocks  are  to  be  dyed,  they  are  placed  in  a  net  made  of  cord,  which  is  suspended  by  hooks 
at  the  side  of  the  vat.  They  are  then  transferred  to  a  stronger  net  and  wrung  out  by  sev- 
eral men.  In  dyeing  flocks  a  more  active  fermentation  of  the  vat  is  required  than  with 
cloth. 

The  process  of  dyeing  by  means  of  sulphate  of  indigo  is  quite  different  from  indigo 
dyeing  in  the  vat.  This  process  was  discovered  by  Barth,  at  Grossenhayn  in  Saxony,  about 
the  year  1740,  and  the  color  produced  by  it  is  hence  called  Saxon  blue.  The  method  of 
purifying  sulphate  of  indigo,  by  immersing  wool  in  the  solution  of  crude  indigo  in  oil  of 
vitriol,  previously  diluted  with  water,  has  been  described  above.  The  process  of  making 
sulphate  of  indigo  or  extract  of  indigo,  as  it  is  called,  as  now  practised  on  the  large  scale, 
is  as  follows  : — 1  lb.  of  indigo  is  mixed  with  from  8  to  9  lbs.  of  oil  of  vitriol,  and  the  mix- 
ture is  left  to  stand  for  some  hours  in  a  room,  the  temperature  of  which  is  90"  Fahr.  It  is 
then  diluted  with  water,  and  filtered  through  paper.  There  is  left  on  the  filter  a  dirty  olive- 
colored  residue,  which  is  used  for  some  purposes  by  woollen  dyers.  By  now  adding  com- 
mon salt  to  the  liquid,  a  blue  precipitate  of  sulphate  of  indigo  is  produced,  which  is  collected 
on  a  filter,  and  washed  with  a  solution  of  salt  in  order  to  remove  the  excess  of  acid.  Xo 
neutralization  with  alkali  is  required  when  this  plan  is  pursued.  The  blue  produced  on  wool 
and  silk  by  means  of  sulphate  of  indigo  is  very  fugitive,  and  is  now  seldom  required,  its 
place  having  been  in  a  great  measure  taken  by  the  blue  from  prussiate  of  potash.  The 
chief  use  of  sulphate  of  indigo  is  for  dyeing  compound  colors,  such  as  green,  olive,  grav, 
&c.— E.  S. 

IODINE  {lod,  Fr. ;  Ind,  Germ.)  is  one  of  the  elementary  substances;  it  was  acci- 
dentally discovered  in  1812  by  M.  Courtois,  a  manufacturer  of  saltpetre  at  Paris.  He 
found  that,  in  the  manufacture  of  soda  from  the  ashe.'^  of  sea-weeds,  the  metallic  vessels 
in  which  the  processes  were  conducted  became  much  corroded;  and  in  searching  for  the 
cause  of  the  corrosion,  he  discovered  this  now  important  substance.  It  was  first  described 
by  Clement  in  1813,  liut  was  afterwards  more  fully  iinestigMted  by  Davy  and  Gay-Lussac. 

Gay-Lussac  and  Clement  at  first  looked  upon  hydriodic  acid  as  hydrochloric  acid, 
until  Sir  H.  Davy  suggested  the  idea  of  its  being  a  new  and  peculiar  acid,  and  iodine  as 
a  substance  analogous  in  its  chemical  relations  to  chlorine. 

It  was  named  iodine  from  the  Greek  word  iwStjs,  violet-colored,  on  account  of  the 
color  of  its  vapor 

Iodine  exists  in  many  mineral  waters  in  combination  with  potassium  and  sodium. 

In  the  mineral  kingdom,  iodine  has  been  found  in  one  or  two  rare  ores,  as  in  a  min- 
eral broustit  from  Mexico,  in  which  it  existed  in  combination  with  silver,  and  also  in  one 
from  Silesia  in  combination  with  zinc. 

It  exists  also  in  very  small  quantities  in  sea  water,  from  which  it  is  extracted  by  many 
sca-wceils,  which  act  tlicrefore  as  concentrators  of  iodine ;  these  sea-weeds  when  diied 
and  ignited  yield  an  ash,  technically  called  kelp,  from  which  all  the  soda  of  commerce  was 
previously  obtained,  but  the  chief  value  of  the  kelp  now  is  on  account  of  the  iodine  which 
it  yields.  The  following  is  the  process  most  generally  adopted  for  the  extraction  of  the 
iodine  from  the  sea-weeds  : — 

The  sun-dried  sea-weed  is  incinerated  in  shallow  excavations  at  a  loio  temperature, 
for  if  the  temperature  was  allowed  to  rise  too  high  a  considerable  quantity  of  iodide  of 
sodium  would  be  lost  by  volatilization.  The  half-fused  ash  or  kelp  which  remains  i.s 
broken  into  fragments,  and  treated  with  boiling  water,  which  dissolves  about  one-half 
of  the  ash. 

The  liquid  thus  obtained  is  evaporated,  when  on  cooling  the  more  crystallizable  salts 


IROK  623 

separate,  viz.,  sulphate  and  carbonate  of  soda,  with  some  chloride  of  potassium.  The 
mother  liquor  still  contains  the  iodide  of  sodium,  sulphide  of  sodium,  sulphide  and  some 
carbonate  of  soda.  This  liquor  is  then  mixed  with  about  one-eighth  of  its  bulk  of 
sulphuric  acid,  and  allowed  to  stand  for  twenty-four  hours;  carbonic  and  sulphurous 
acid  and  sulphuretted  hydrogen  gases  escape,  a  fresh  quantity  of  sulphate  of  soda  crys- 
tallizing out,  mixed  with  a  precipitate  of  sulphur. 

The  supernatant  acid  liquor  is  then  transferred  to  a  leaden  still,  to  which  is  adapted 
a  double  tubulated  leaden  head  luted  on  with  pipe-clay ;  it  is  then  heated  to  14U°  F., 
when  binoxide  of  manganese  is  added. 

The  temperature  may  be  gently  raised  to  212°  F.,  but  not  higher,  as  some  chlorine 
would  come  over,  and  combine  with  some  of  the  iodine,  forming  chloride  of  iodine. 

The  iodine  is  condensed  in  spherical  ghiss  condensers,  each  having  two  mouths 
opposite  to  each  other,  and  inserted  the  one  into  the  other,  the  end  one  being  fitted  to 
the  neck  of  the  leaden  head. 

The  iodine  is  purified  by  resublimation. 

The  following  formula  represents  the  reaction  : 

Iodide  of       Oxide  of       Sulphuric        Sulphate  of       Sulphate  of       Iodine.  Water. 

Sodium.     Manganese.  Acid.  Soda.  Manganese. 

Nal    +    MuO-      +   2HS0'  =    NaSO*     +     MnSO*       -|-     I        -t-        2H0 

The  British  iodine  is  exclusively  manufactured  at  Glasgow,  from  the  kelp  of  the  west 
coast  of  Ireland  and  the,  western  islands  of  Scotland. 

Iodine  is  a  crystallizable  solid,  its  primary  form  being  a  rhombic  octohedron.  It  is 
however  usually  met  with  in  micaceous,  soft,  friable  scales,  having  a  grayish-black  col- 
or, a  metallic  lustre,  and  an  acrid  hot  taste.  Even  at  ordinary  temperatures,  and  more 
especially  when  moist,  it  is  sensibly  volatile,  emitting  an  odor  like  that  of  chlorine,  only 
much  weaker. 

At  225°  F.  it  fuses,  and  at  347°  F.  boils,  and  is  converted  into  a  magnificent  violet 
vapor.  It  may  nevertheless  be  distilled,  in  the  presence  of  steam,  at  a  temperature  of 
212°,  as  is  seen  in  the  process  of  niiinufacture. 

Iodine,  in  the  solid  state,  has  a  specific  gravity  of  4*947,  the  specific  gravity  of  the 
vapor  being,  according  to  Dumas,  8'716.  Iodine  is  only  very  slightly  soluble  in  water, 
it  requiring  7,000  parts  of  water  to  dissolve  it ;  even  then  it  imparts  a  yellow  color  to  the 
solution,  and  is  used  in  that  state  as  a  test  for  starch,  with  which  it  forms  a  beautiful 
blue  compound,  which  is,  however,  destroyed  by  heat. 

Alcohol  and  ether  dissolve  it  more  readily  ;  but  the  most  powerful  solvents  of  iodine 
are  the  solutions  of  the  iodides.  Iodine  stains  the  skin,  and  most  organic  substances, 
of  a  brown  color  ;  it  attacks  the  metals  rapidly,  iron  or  zinc  being  readily  dissolved  by 
it  if  placed  in  water  with  it,  an  iodide  of  the  metal  being  formed. 

All  tlje  compounds  of  iodine  with  the  metals  and  with  hydrogen  are  decomposed  by 
chlorine,  and  even  by  bromine,  iodine  being  set  free.  Advantage  is  taken  of  this  fact  in 
detecting  the  presence  of  iodine.  If  the  iodine  exists  in  combination  with  a  metal,  or  as 
hydriodic  acid,  its  solution  will  not  form  the  characteristic  intense  blue  compound  with 
starch,  but  on  the  addition  of  a  little  chlorine,  or  solution  of  bleaching-powder,  the  iodine 
is  set  free  and  forms  the  blue  compound  with  the  starch.  If,  however,  the  iodine  exists 
as  iodic  acid,  it  will  not  act  upon  starch  until  reduced  by  some  reducing  agent,  as  sulphu- 
rous acid.  In  using  the  chlorine  care  must  be  taken  not  to  use  too  much,  as  it  would 
unite  with  the  iodine  and  prevent  it  acting  on  the  starch. 

Iodine  is  used  to  a  considerable  extent  in  medicine;  when  taken  in  large  doses  it  is 
an  irritant  poison,  but  in  small  doses  it  is  a  most  valuable  medicine,  particularly  in  glan- 
dular swellings,  and  in  certain  forms  of  goitre.  It  is  also  much  used  in  photographv. 
The  chemical  symbol  for  iodine  is  1 ;  its  equivalent  number  126-88  ;  and  the  combining 
volume  of  its  vapor  2. — H.  K.  B. 

IRON".  The  modern  processes  of  iron-smelting  differ  materially  according  as  the  fuel 
employed  is  charcoal  or  pit-coal.  As  an  illustration  of  the  method  adopted  when  the 
former  is  used,  the  following  details  of  the  manufacture  of  the  celebrated  "  Oercgrund 
iron  "may  be  taken,  premising  that  the  operations  vary  in  a  few  particulars  in  "other 
countries  where  different  kinds  of  ore  are  dealt  with.  The  oercgrund  iron  is  made  from 
the  magnetic  ironstone  of  Dannemora  in  Sweden.  The  ore,  in'moderately  large  pieces, 
such  as  it  comes  from  the  mine,  is  first  roasted.  For  this  purpose  an  oblong  coll'er  of 
masonry,  18  feet  long,  15  feet  wide,  and  about  0  feet  in  dejjth,  open  at  top,  and  fur- 
nished with  a  door  at  one  of  its  sin:dler  extremities,  is  entirely  filled  with  logs  of  wood; 
over  this  the  ore  is  piled  to  the  height  ot  from  5  to  7  feet,  anil  is  covered  with  a  coating 
of  small  charcoal,  almost  a  foot  and  a  half  in  thickness.  Fire  is  then  comnnniicated  to 
the  bottom  of  the  pile,  by  m(!ans  of  the  door  just  mentioned,  and  in  a  short  time  the 
combustion  spreads  through  the  whole  mass;  the  small  quantity  of  j)yrites  that  the  ore 
contains  is  decomposed  by  the  volatilization  of  the  sulphur;  the  moisture  is  also  driven 
off,  and  the  ore,  from  being  very  hard  and  refractory,  becomes  pretty  easily  pulverizuble. 


624 


lEOK 


In  the  space  of  twenty-four  hours  the  roasting  is  completed;  and  the  ore  when  suffi- 
ciently cool  ia  transferred  to  a  stamping-mill,  where  it  is  pouaded  dry,  and  afterwards 
sifted  through  a  network  of  iron,  which  will  not  admit  any  piece  larger  than  a  hazel-nut 
to  pass.  It  is  now  ready  to  be  smelted.  The  smelting-furnace  is  a  strong  quadrangular 
pile  of  masonry,  the  internal  form  of  which,  though  simple  in  form,  is  not  very  easily 
described.  It  may  be  considered  in  general  as  representing  two  irregular  truncated 
cones,  joined  base  to  base;  of  these  the  lower  is  scarcely  more  than  one  third  of  the 
upper,  and  is  pierced  by  two  openings,  through  the  upper  end  of  which  the  blast  of  wind 
from  the  blowing  machine  is  admitted  into  the  furnace;  and  from  the  lower  the  melted 
matter,  both  scoriaj  and  metal,  is  discharged  from  time  to  time  at  the  pleasure  of  the 
workmen. 

The  furnace  is  first  filled  with  charcoal  alone,  and  well  heated,  after  which  alternate 
charges  are  added  of  ore,  either  alone  or  mixed  with  limestone  (if  it  requires  any  flux) 
and  charcoal ;  the  blast  is  let  on,  and  the  metal  in  the  ore  being  highly  carbonized  in  its 
passage  through  the  upper  part  of  the  furnace,  is  readily  melted  as  soon  as  it  arrives  in 
the  focus  of  the  blast,  whence  it  subsides  in  a  fluid  state  to  the  bottom  of  the  furnace, 
covered  with  a  melted  slag.  Part  of  the  clay  that  closes  the  lower  aperture  of  the  fur- 
nace is  occasionally  removed,  to  allow  the  scoria?  to  flow  out.  and  at  the  end  of  every 
ninth  hour  the  iron  itself  is  discharged  into  a  bed  of  sand,  where  it  forms  from  ten  to 
twelve  small  pigs.  As  soon  as  the  iron  has  flowed  out,  the  aperture  is  closed  again,  and 
thus  the  furnace  is  kept  in  incessant  activity  during  the  first  six^motiths  of  the  year;  the 
other  six  months  are  employed  in  repairing  the  furnaces,  making  charcoal,  and  collect- 
ing the  requisite  provision  of  wood  and  ore.  The  next  process  for  converting  the  pig 
into  bar  iron  is  refining ;  for  this  purpose  a  furnace  is  made  use  of,  resembling  a  smith's 
hearth,  with  a  sloping  cavity,  sunk  from  ten  to  twelve  inches  below  the  level  of  the  blast- 
pipe.  This  cavity  is  filled  with  charcoal  and  scoriae,  and  on  the  side  opposite  to  the 
blast-pipe  is  laid  a  pig  of  cast  iron  well  covered  with  hot  fuel.  The  blast  is  then  let  in, 
and  the  pig  of  iron,  being  placed  in  the  very  focus  of  the  heat,  soon  begins  to  melt,  and 
as  it  liquefies,  runs  down  into  the  cavity  below ;  here,  being  out  of  the  direct  influence 
of  the  blast,  it  becomes  solid,  and  is  then  taken  out,  and  replaced  in  its  former  position. 
The  cavity  being  then  filled  with  charcoal,  it  is  thus  fused  a  second  time,  and  after  that 
a  third  time,  the  whole  of  these  three  processes  being  usually  effected  in  between  three 
and  four  hours.  As  soon  as  the  iron  has  become  solid  it  is  taken  out,  and  very  slightly 
hammered  to  free  it  from  the  adhering  scorite:  it  is  then  returned  to  the  furnace,  and 
placed  in  a  corner,  out  of  the  way  of  the  blast,  and  well  covered  with  chaicoal,  where  it 
remains,  till,  by  further  gradual  cooling,  it  becomes  sufficiently  compact  to  bear  the  tilt 
hammer.  Here  it  is  well  beaten  till  the  scoria)  are  forced  out,  and  it  is  then  divided  into 
several  pieces,  which,  by  a  repetition  of  heating  and  hammering,  are  drawn  into  bars,  and 
in  this  state  is  ready  for  sale.  The  proportion  of  pig  iron  obtained  from  a  givci^  quantity 
of  ore  is  subject  to  considerable  variation,  from  the  difference  in  the  metallic  contents  of 
different  parcels  of  ore  and  other  circumstances;  but  the  amount  of  bar  iron  that  a  given 
weight  of  pig  metal  is  expected  to  yield  is  regulated  very  strictly,  the  workmen  being 
expected  to  furnish  four  parts  of  the  former  for  five  parts  of  the  latter,  so  that  the  loss 
does  not  exceed  20  per  cent. 

In  some  parts  of  America,  particularly  in  the  States  of  Vermont  and  New  Jersey,  the 

Catalan  forge  is  extensively  employed  for 
smelting  the  rich  magnetic  ores  which 
there  abound.  The  form  of  this  fire, 
(which  is  nearly  uniform  everywhere,)  and 
the  manipulation  with  it  in  America,  is 
thus  described  by  Overman  : — The  whole 
is  a  level  hearth  of  stone  work,  from  6  to 
8  feet  square,  at  the  corner  of  which  is  the 
fireplace,  from  24  to  SO  inches  square,  and 
from  16  to  18,  often  20,  inches  deep.  In- 
side it  is  lined  with  cast-iron  plates,  the 
bottom  plate  being  from  2  to  3  inches 
thick.  Fif/icrc  332  represents  a  cross  sec- 
tion through  the  fireplace  and  tuyere, 
commonly  called  tue  iron;  li  represents  the  fireplace,  which,  as  remarked  above,  is  of 
various  dimensions.  Tiie  tuyere  b  is  from  7  to  8  inches  above  the  bottom,  and  more  or 
less  inclined  according  to  circumstances.  The  blast  is  produced  by  wooden  bellows  of 
the  common  form,  or  more  generally  by  square  wooden  cylinders,  urged  by  water-wheels. 
The  ore  chiefly  employed  is  the  crystallized  magnetic  ore.  This  ore  very  readily  falls  to 
a  coarse  sand,  and  when  roasted  varies  from  the  size  of  a  pea  to  the  finest  grain.  Some- 
times the  ore  is  employed  without  roasting.  In  the  working  of  such  fires  much  depends 
on  the  skill  and  experience  of  the  workman.  The  result  is  subject  to  considerable  varia- 
tion, that  is,  whether  economy  of  coal  or  that  of  ore  is  our  object.     Thus  a  modification 


331 


IRON. 


625 


332 


is  required  in  the  construction  either  of  the  whole  apparatus  or  in  parts  of  it.  The 
manipulation  varies  in  many  re- 
spects. One  worlcman,  by  inclining 
his  tuyere  to  the  bottom,  saves  coal 
at  the  expense  of  obtaining  a  poor 
yield.  Another,  by  carrying  his  tue 
iron  more  horizontally  at  tlie  com- 
mencement, obtains  a  larger  amount 
of  iron,  thongli  at  the  sacrifice  of 
coal.  Good  workmen  pay  great  at- 
tention to  the  tuyere,  and  alter  its 
dip  according  to  the  state  of  the 
operation.  The  general  manipula- 
tion is  as  follows: — The  hearth  is 
lined  with  a  good  coating  of  char- 
coal dust;  and  the  fire  plate,  or  the 
plate  opposite  the  blast,  is  lined  with 
coarse  ore,  in  case  any  is  at  our  dis- 
posal. If  no  coarse  ore  is  employed, 
the  hearth  is  filled  with  coal,  and 
the  small  ore  piled  against  a  dam  of 
coal  dust  opposite  the  tuyere.  The 
blast  is  at  first  urged  gently,  and 
directed  upon  the  ore,  while  the  coal 
above  the  tuyere  is  kept  cool.  Four 
hundred  pounds  of  ore  are  the  com- 
mon charge,  two-thirds  of  which 
are  thus  smelted,  and  the  remain- 
ing third,  generally  the  finest  ore, 
is   held    in    reserve,  to   be    thrown 

on  the  charcoal  when  the  fire  becomes  too  brisk.  The  charcoal  is  piled  to  the  height  of 
two,  sometimes  even  three  and  four  feet,  according  to  the  amount  of  ore  to  bo  smelted. 
When  the  blast  has  been  applied  for  an  hour  and  a  half  or  two  hours,  most  of  the  iron 
is  melted,  and  forms  a  pasty  mass  at  the  bottom  of  the  hearth.  The  blast  may  now  be 
urged  more  strongly,  and  if  any  pasty  or  spongy  mass  yet  remains,  it  may  be  brought 
within  the  range  of  the  blast  and  melted  down.  In  a  short  time  the  iron  is  revived,  and 
the  scoriae  are  permitted  to  flow  through  the  tapping  hole  c,  so  that  but  a  small  quantity 
of  cinder  remains  at  the  bottom.  By  means  of  iron  bars,  the  lump  of  pasty  iron  is 
brought  before  the  tuyere.  If  the  iron  is  too  pasty  to  be  lifted,  the  tuyere  is  made  to  dip 
into  the  hearth  ;  in  this  way  the  iron  is  raised  from  the  bottom,  directly  before,  or  to  a 
point  above  the  tuyere,  until  it  is  welded  into  a  coherent  ball,  twelve  or  fifteen  inches  in 
diameter.  This  ball  is  brought  to  the  hammer  or  squeezer,  and  shingled  into  a  bloom, 
which  is  either  cut  in  pieces  to  be  stretched  by  a  hammer,  or  sent  to  the  rolling-mill  to 
be  formed  into  marketable  bar  iron.  A  mixture  of  fibrous  iron,  cast  iron,  and  steel,  is 
the  result  of  the  above  process ;  the  quality  of  the  iron  depends  entirely  on  the  quality 
of  the  ore,  for  there  are  no  opportunities  for  the  exercise  of  any  skill  to  create  improve- 
ments in  the  process;  poor  ores  cannot  be  smelted  at  all.  In  Vermont,  where  the  rich 
magnetic  ores  are  employed,  a  ton  of  blooms  costs  about  40  dollars ;  4  tons  of  ore  and 
300  bushels  of  charcoal  are  required  to  produce  1  ton  of  blooms.  The  Foiirnemix  u  piece 
of  the  French,  or  Siuck-ofe7i  of  the  Germans,  holds  a  place  intermediate  between  the 
Catalan  hearth  and  the  high  blast  furnace  now  in  general  use.  The  iron  produced  in  this 
kind  of  furnace  is  generally  of  a  very  superior  kind,  but  it  is  very  little  in  use  at  the  pres- 
ent time,  on  account  of  the  great  expense  of  its  manipulation.  The  Siuck-ofen,  or  Sala- 
majider  furnace,  as  it  is  sometimes  called,  is  a  small  cupola,  its  interior  having  the  form 
of  a  double  crucible.  It  is  usually  from  10  to  Ifi  feet  high,  and  24  inches  wide  at  bottom 
and  top;  and  measures  at  its  widest  part  about  5  feet.  There  are  generally  two  tuyeres, 
both  on  the  same  side ;  the  breast  is  open,  but  during  the  smelting  operation  it  is  shut  by 
bricks.  The  furnace  is  heated  previous  to  closing  in  the  breast;  after  which  charcoal 
and  ore  are  thrown  in ;  the  blast  is  then  turned  on  ;  as  soon  as  the  ore  passes  the  tuyere, 
iron  is  deposited  at  the  bottom  of  the  hearth ;  when  the  cinder  rises  to  the  tuyere,  a 
portion  is  suffered  to  escape  through  a  hole  in  the  dam ;  the  tuyeres  are  generally  kept 
low  upon  the  surface  of  the  melted  iron,  which  thus  becomes  whitened;  as  the  iron  rises 
the  tuyeres  are  raised.  In  about  24  hours  one  ton  of  iron  is  deposited  at  the  bottom  of 
•the  furnace,  the  blast  is  turned  off",  and  the  iron,  which  is  in  a  solid  mass,  in  the  form  of 
a  salamander,  or  Stiick  wolf,  as  the  Germans  call  it,  is  lifted  loose  from  the  bottom  by 
crowbars,  taken  by  a  pair  of  strong  tongs,  which  arc  fastened  on  chains,  suspended  on  a 
swing  crane,  and  then  removed  to  an  anvil,  where  it  is  flattened  by  a  tilt  hammer  into 
Vol.  III.— 10 


626 


IRON. 


four-inch  thick  slabs,  cut  into  blooms,  and  finally  stretched  into  bar  iron  by  smaller 
hammers.  Meanwhile  the  furnace  is  charged  anew  with  ore  and  coal,  and  the  same  pro- 
cess is  renewed.  This  process,  as  well  as  that  of  the  Catalan  hearth,  is  impracticable 
with  ores  containing  much  foreign  matter,  or  less  than  40  per  cent,  of  metal. 

The  general  form  of  the  modern 
333  CT~^  charcoal  blast  furnace,  as  used  in  the 

United  States,  where  this  fuel  is  far 
more  common  than  pit-co;il,  (indeed, 
it  is  doubtful  whether  any  coke  fur- 
naces are  at  the  present  time  in  opera- 
tion in  that  country,)  is  shown  in  ver- 
tical section  in /?(/.  333,  and  in  section 
through  the  tuyere  arches  in  Jfg.  334. 
Tiie  ores  designed  to  be  smelted  in 
this  furnace  are  hydiatod  oxides  of 
iron,  such  as  brown  haematite,  brown 
iron  stone,  pi[)e  ore,  and  bog  ore?. 
The  height  is  35  feet ;  hearth  from 
base  to  the  boshes,  5  feet,  6  inches; 
width  at  the  bottom,  24  inches;  and 
at  top,  36  inches.  The  tuyeres  are  20 
inches  above  the  b.ise.  The  boshes 
are  9  feet  6  inches  in  diameter,  and 
measure  from  the  top  of  the  crucible 
4  feet,  wliich  gives  about  60°  slope. 
The  blast  is  conducted  through  sheet- 
iron  or  cast-iron  pipes  laid  below  the 
bottom  stone  into  the  tuyeres.  The 
top  is  furiiished  with  a  chimney,  by 
which  the  blaze  from  the  tunnel  head 
is  drawn  off.  Around  the  top  is  a 
fence  of  iron  or  wood.  Ficf.  335  shows 
the  method  of  preparing  and  arrang- 
ing the  hearth-stones,  a  is  the  bottom 
stone,  made  of  a  fine  close-grained 
sand-stone,  from  12  to  15  inches  thick, 
at  least  4  feet  wide,  and  6  feet  long; 
it  reaches  underneath  at  least  lialf  of 
the  dam-stone  b.  This  bottom  stone 
is  well  bedded  in  fire-clay,  mixed  with 
three-fourths  sand.  After  the  bot- 
tom stone  is  placed,  the  upper  part  of 
which  must  be  tlirce-fourths  of  an 
inch  lower  at  the  dam-stone  than  at 
the  back,  the  two  side  stones  c,  are 
laid  embedded  in  fire-clav.  These 
stones  must  be  at  least  6  feet  and  a 
half  long,  reaching  fiom  18  inches 
behind  the  crucible  to  the  middle  of 
the  dam-stone.  Their  form  is  most 
commonly  square,  that  is,  a  prism  of 
four  equal  sides;  the  transverse  sec- 
tion of  the  grain  must  be  in  all  cases 
placed  towards  the  fire ;  the  side  stones 
arc  sometimes  square,  but  oftencr 
bevelled  according  to  the  slope  of  tlie 
hearth.  Upon  these  stones  the  tuyere 
stones  d  are  bedded;  the  latter  suffer 
much  from  heat,  and  therefore  ought 
to  be  of  the  best  quality.  They  should 
be  from  20  to  24  inches  square,  or 
even  larger;  the  tuyere  holes/,  a 
kind  of  taper  arch,  are  cut  out  before 
the  stones  are  bedded.  These  stones  do  not  reach  further  than  to  the  front  or  tiinpstone  r/, 
and  arc  therefore  scarcely  four  feet  long;  the  top  stone  <*,  is  generally  sufficiently  high  lo 
raise  at  once  the  crucible  to  its  destined  height.  After  both  sides  are  finished  the  back 
stone  I  is  put  in,  and  then  the  timsptone  y;  the  space  between  the  hearthstones  and  the 
rough  Willi  of  the  furnace  stack  is  filled  and  walled  up  with  common  brick  or  stone.s. 


IRON". 


62r 


335 


In  starting  a  charcoal  furnace,  it 
is  first  thoroughly  dried  by  burning  a 
fire  for  several  weeks  in  the  interior, 
which  has  a  temporary  lining  of 
bricks.  The  lower  part  of  the  fur- 
nace or  the  hearth  is  then  filled  grad- 
ually with  charcoal,  and  when  the 
fuel  is  well  ignited,  and  the  furnace 
half  filled,  ore  may  be  charged  in  ;  it 
is  sometimes  advisable  to  increase 
the  draught  by  forming  grates  by 
laying  across  the  timp  a  short  iron 
bar,  as  high  up  as  the  dum-stone,  by 
resting  U[)on  this  bar  six  or  seven 
other  bars  or  ringers,  and  by  pushing 
their  points  against  the  back  stone 
of  the  hearth.  There  is  not  much  iron 
made  during  the  first  24:  hours ;  most 
of  the  ore  is  transfornied  into  slag, 
and  the  iron  which  comes  down  gets  cold  on  the  bottom  stone,  wiiere  it  is  retuitied ;  the 
blast  should  not  be  urged  too  fast  at  first,  but  increased  grjidually,  in  order  to  avoid  the 
serious  evil  arising  from  the  cold  hearth ;  if  all  gops  on  well  the  hearth  will  be  free  from 
cold  iron  or  clinkers  in  a  week,  the  yield  of  iron  will  increase,  and  the  burden  mav  be  in- 
creased, likewise.  The  average  charge  of  charcoal,  which  should  be  dry,  coarse,  and  hard, 
is  about  15  bushels.  According  to  Overman's  experience,  the  most  favorable  height 
for  a  charcoal  furnace  is  35  or  36  feet;  if  below  this  standard  they  consume  too  much 
fuel,  if  above  they  are  troublesome  to  work;  if  it  be  desired  to  enlarge  the  capacity  of  a 
furnace,  he  thinks  it  better  to  increase  the  diameter  of  the  boshes,  or  to  curve  theverti- 
cal  section.  There  is  much  difference  of  opinion  amongst  managers  of  furnaces  on  the 
subject  of  the  proper  size  for  the  throat  of  the  furnace ;  the  tendency  of  narrow  throats 
would  seem  to  be  to  consume  more  coal  than  wide  ones,  inasmuch  as  in  Pennsylvania 
and  throughout  the  whole  west,  where  narrow  tops  are  preferred,  the  consumption  of 
charcoal  per  ton  of  iron  is  from  160  to  180  bushels,  while  in  the  State  of  New  York,  and 
further  east,  where  the  furnace  throats  are  wider,  the  consumption  is  from  120  to  130 
bushels.  Another  subject  which  demands  the  strictest  attention  is  the  regulation  of  the 
blast.  A  weak  soft  charcoal  will  not  bear  a  much  greater  pressure  than  from  half  a 
pound  to  five-eighths  of  a  poimd  to  the  square  inch  ;  strong  coarse  charcoal  will  bear 
from  three-quarters  of  a  pound  to  a  pound;  and  again,  it  may  be  laid  down  as  a  rule  that 
the  larger  the  throat  in  proportion  to  the  boshes,  the  stronger  ought  to  be  the  blast,  and 
that  a  narrow  top  and  wide  boshes,  while  they  permit  a  weaker  blast,  involve  the  loss  of 
much  fuel.  In  every  case  a  careful  roasting  of  the  ores  at  charcoal  furnaces  will  prove 
advantageous;  this  is  the  surest  means  of  saving  coal  and  blast  and  of  avoiding  many 
annoyances  in  the  working  of  the  furnace. 

With  regard  to  hot  blast,  as  applied  to  charcoal  furnaces.  Overman  remarks,  that 
under  some  circumstances  it  might  be  advantageous,  but  in  others  it  is  decidedly  injuri- 
ous; that  it  is  at  least  a  questionable  improvement,  and  it  may  be  doubted  whether  the 
manufacture  of  bar  iron  has  derived  any  benefit  from  it ;  qualitatively  it  has  not.  Hot 
blast  is  quite  a  help  to  imperfect  workmen:  it  melts  refractory  ores,  and  delivers  good 
foundry  metal  with  facility. 

Enrjlinh  process  of  iron  maJci^ig. — Mr.  Hunt,  in  his  very  valuable  "Mineral  Slatis- 
tics,"  gives  us  the  total  quantity  of  pig  iron  produced  in  Great  Britain  hi  the  year  1858: 

Northumberland 45,312  tons. 

Durham 265,184 

Yorkshire,  North  Riding 189,320 

Do.      West  Riding 85,936 

Derbyshire 131,577 

Lancashire 2,840 

Cumberland 26,264 

Shropshire 101,016 

North  Staffordshire 135,308 

South  Staffordshire  and  Worcestershire       -        -        -       597,809 

Gloucestershire 23,530 

Northamptonshire       • 9,760 

Wilts  and  Somerset 2,040 

North  Wales 28,150 

South  Wales 886,478 

Scotland 925,500 

3,456,064  tons. 


628  IRON. 

The  number  of  furnaces  in  blast  to  furnish  this  astonishing  make  are,  in  England,  332, 
distributed  over  162  iron  works;  in  Wales,  153,  distributed  over  57  works;  and  in  Scot- 
land, 133,  over  32.  To  supply  these  furnaces  there  were  raised  8,040,959  tons  of  ore, 
the  estimated  value  of  which,  at  a  mean  of  lis.  per  ton,  is  £-1,422,527  ;  that  of  the  pig 
iron,  at  a  mean  money  value  of  f4a  ton,  being  £13,824,256.  Of  the  ironstone  1,650,000 
tons  were  argillaceous  carbonate  from  the  coal  measures  of  Staffordshire  and  Worcester- 
shire;  nearly  1,500,000  tons  from  the  coal  measures  of  North  and  South  Wales;  and 
2  212,250  tons  argillaceous  carbonate  from  Scotland.  The  annual  production  of  pig 
iron  over  the  whole  world  was  estimated  by  Mr.  Bhtckwell,  in  December,  1855,  as  fol- 
lows : — 

Tons. 

Great  Britain 3,000,000 

France 750,000 

United  States  of  America 750,000 

Prussia 300,000 

Austria 250,000 

Belgium 200,000 

Russia 200,000 

Sweden 150,000 

Various  German  States 100,000 

Other  countries 300,000 


6,000,000 


From  which  it  appears  that  the  quantity  of  iron  made  annually  in  this  island  alone,  is 
nearly,  if  not  quite,  as  large  as  the  total  quantities  produced  in  all  other  countries.  The 
nature  of  the  ore  which  forms  the  staple  supply  of  the  English  furnaces,  (argillaceous 
carbonate,)  and  the  universal  adoption  of  coke  and  coal  as  fuel,  have  led  by  necessity  to 
a  method  of  manufacture  of  iron  quite  peculiar  to  this  country,  and  wholly  inapplicable 
to  those  establishments  that  are  carried  on  by  means  of  charcoal.  We  shall  proceed  to 
describe  the  various  steps  of  this  manufacture  in  detail : — and  first, 

Of  the  blast  furnace. — The  blast  furnaces  at  present  in  use  are  of  various  sizes,  being 
from  35  to  60  feet  in  height,  and  at  the  boshes,  or  widest  part,  from  12  to  17  feet.  The 
internal  form  commonly  adopted  consists  essentially  of  two  frustrums  of  cones  meeting 
each  other  at  their  bases,  at  the  point  where  the  widest  part  or  the  top  of  the  boshes  is 
situated.  From  this  point  the  furnace  gradually  contracts  both  upwards  to  its  mouth, 
and  downwards  to  the  level  of  the  tuyeres  below.  The  hearth,  properly  speaking,  is 
that  part  of  the  furnace  only  which  receives  the  fluid  metal  and  cinder,  as  they  fall  be- 
low the  level  of  the  tuyeres. "  It  forms  a  short  prolongation  from  that  point  of  the  lower 
inverted  cone.  From  the  boshes  upwards  the  width  gradually  decreases  to  the  tunnel 
head,  which  varies  from  7  to  9  feet  in  diameter,  according  to  the  size  of  the  furnace. 
The  hearth  is  generally  a  cube,  from  2^  to  3  feet  square.  The  air  is  introduced  by  one, 
two,  or  three  small  apertures,  called  tuyeres.  When  two  tuyeres  are  used,  the  orifices 
of  their  blowpipes  are  about  three  inches  in  diameter,  and  the  pressure  of  blast  is  from 
2^  to  3  lbs.  on  the  square  inch.  To  prevent  the  tuyeres  from  being  melted  by  the  in- 
tense heat  to  which  they  are  exposed,  a  stream  of  cold  water  is  caused  constantly  to 
flow  round  their  nozzles  by  an  arrangement  which  will  be  immediately  understood  by  an 

inspection  o^  fig.  336,  which  represents 
^^^  a  section   of  a  tuyere  nozzle    thus  pro- 

tected, the  cold  water  entering  the  cas- 
ing by  the  tube  a,  and  the  hot  water 
running  off  by  the  tube  b.  The  upper 
part  of  the  furnace  above  the  boshes  is 
called  the  cone  or  body.  It  is  formed 
by  an  interior  lining  of  fire-brick,  about 
•jU  14  inches  in  thickness,  between  which  and 

the  exterior  masonry  is  a  casing  of  fine 
refractory  sand  compactly  rammed  in, 
air  holes  being  left  for  the  escape  of  aqueous  vapor.  In  the  base  of  the  furnace  four 
arches  are  left,  the  back  and  sides  are  called  tuyere  houses,  the  front  is  called  the  cinder 
fall ;  the  bottom  of  the  furnace  is  formed  either  of  large  blocks  of  coarse  sandstone  or 
of  large  fire-bricks.  The  materials  are  charged  into  the  furnace  through  the  tuimcl  head, 
which  is  provided  with  one  or  more  apertures  for  the  purpose.  The  general  form  of  a 
blast  furnace  is  shown  Infr/.  337,  and  the  following  measurements  represent  the  interior 
structure  of  two  that  worked  well : — 


IRON. 


629 


No.  1. 
45 

6i 

8 

8 

2i 

3 
12J 
12 

8* 

4i 
59° 


No.  2. 
49 
6 

1 

36 

12| 

2 

2J 
13i 
IH 

H 

52° 


Height  from  the  hearth  to  the  throat  or  mouth  - 
Height  of  the  crucible  or  hearth        _        .        . 

"        of  the  boshes         

"         of  the  cone 

"         of  the  chimney  or  mouth  ... 

Width  of  the  bottom  of  the  hearth*     ... 

"     at  its  upper  end 

"     of  the  boshesf 

"     at  one-third  of  the  belly     -         -         .         - 

"     at  two-thirds  of  ditto 

"     at  mouth 

Inclination  of  the  boshes:}:  -         -         -         -         . 

The  form  of  the  blast  farnace 
from  the  boshes  to  the  throat  is  ex- 
hibited in  Jiff.  337  as  a  truncated 
cone,  and  such  was  formerly  in- 
variably the  construction  ;  of  late 
years,  nowever,  considerable  varia- 
tions have  been  introduced.  In 
Scotland  the  body  of  the  furnace 
frequently  is  carried  up  cylindrical, 
or  nearly  so,  for  a  considerable 
height,  terminating  with  the  usual 
truncated  cone  to  the  mouth  ;  in 
other  places  a  curved  line  is  substi- 
tuted for  a  straight  one.  The  form 
adopted  in  some  furnaces  recently 
erected  at  Ebbw  Vale  and  Blaina  is 
shown  iu^^.  338. 

The  diameter  of  the  throat  or 
filling  place  is  a  subject  of  very 
great  importance  to  the  operations 
of  the  furnace.  Most  iron  masters 
are,  we  believe,  agreed  as  to  the 
impolicy  of  the  narrow  tops  for- 
merly adopted ;  tlie  waste  of  fuel 
in  such  furnaces,  where  the  width 
of  the  throat  scarcely  averaged  one- 
fourth  of  the  diameter  of  the  fur- 
nace, was  very  great,  the  average  yield  of  coal  to  the  ton  of  crude  iron  exceeding  6  tons; 
by  enlar2;ing  the  throat  to  one-third,  the  consumption  of  coal  was  reduced  to  4  tons,  and 
by  continuing  the  enlargement  to  one-half  it  was  reduced  to  2  tons.  Mr.  Truran  states 
that  on  reducing  the  diameter  of  the  throat  of  a  furnace  at  Dowlais  from  9  feet  to  6,  the 
make  of  pig  iron  weekly  fell  off  from  97  tons,  to  an  irregular  make  of  from  50  to  70  tons ; 
and  that  while  with  the  9-feet  throat  the  consumption  of  coal  was  45  cwts.  to  the  ton  of 
iron,  it  rose  with  the  6-feet  throat  to  70,  80,  90  cwts.,  the  quality  of  the  iron  being  ex- 
ceedingly bad.  On  enlarging  the  throat  to  9^  feet,  the  make,  for  a  period  of  6  months, 
averaged  over  160  tons,  with  a  good  yield  of  coal  and  other  materials.  Mr.  Truran  ap- 
pears to  question  the  utility  of  reducing  the  diameter  of  the  furnace  at  the  top,  which 
was  only  adopted  in  the  first  place  from  an  erroneous  impression  tliat  the  furnace  could 
be  filled  best  through  a  contracted  mouth ;  but  it  may  be  questioned  whether  this  widen- 
ing of  the  throat  may  not  be  carried  too  far,  so  as  to  disperse  the  heated  gases  too  rapid- 
ly, and  whether  a  diameter  much  greater  than  one-half  of  the  largest  dimensions  of  the 
furnace  above  the  boshes  can  with  utility  be  adopted.  On  this  subject  Mr.  Kenyon  Black- 
well  says:  "  If  that  part  of  the  blast  furnace  commencing  at  the  point  where  it  attains  its 
greatest  width  were  continued  of  the  same  wide  dimensions  iipwards  to  its  mouth,  two 
o'ljectionablc  results  would  ensue:  first,  the  upper  part  of  the  furnace  would  be  cooled  by 
the  too  rapid  dispersion  of  the  ascending  column  of  heated  gases,  and  by  the  entire  ab- 
sence of  the  reverberating  effect  of  the  contracted  mouth ;  and  secondly,  the  materials 

*  The  width  of  the  hfarth  difFers  preatly  in  the  furnaces  in  different  localities.  In  Scotland  it  varies 
from  6  to  8  foot;  in  tlic  Wclsli  fiirnacos  from  .5  to  S  feet.  When  coke  is  used  as  fuel  Mr.  Truran  thinks 
6  feet  a  sufficient  width  for  all  purjio.ses;  but  with  coal,  with  full-sized  furnaces,  16  to  19  feet  across  the 
boshes;  he  thinks  a  7-f  et  hearth  to  be  more  advantaireous. 

t  The  diameter  of  the  boshes  in  some  of  the  Welsh  furnaces  is  as  much  as  from  18  to  19  feet. 

X  The  anirlo  with  which  the  boshes  rise  in  different  furnaces  varies  from  50°  to  80°.  Mr.  Tnirnn 
thinks  that  when  the  full  smeltinp:  pciwer  of  the  furnace  is  desired,  the  angle  should  not  be  less  than  70", 
which  is  about  that  of  the  Scotch  furnaces. 


630 


IRON. 


could  not  be  equally  spread  from  the  filling  holes  over  so  wide  a  surface.     The  diameter 
of  the  upper  part  furnace  ought,  therefore,  to  be  such  as  will  cause  the  materials  thrown 

in  at  the  fill- 
'^  "'"'  iiig    holes    to 

distribute 
them  selves 
equally    in 
their  descent 
over    every 
part    of     the 
sectional  area 
of    the     fur- 
nace, and  will  produce  such  a  rever- 
beration only  of  heat  as  shall  be  suffi- 
cient to  expel  the  water  and  carbonic 
acid  contained  in  the  materials,  with- 
out consuming  any  of  the  carbon  of 
the  fuel,  which  ought  to  remain  intact 
until  it  reaches  the  lower  regipns  of 
the  furnace,  where  it  is  vaporized  as 
carbonic  oxide,  and  produces  the  re- 
actions on  which  the  reduction  of  the 
ore  depends." 

Calcination  of  the  ironatone. — This 
is  effected  either  in  kilns,  or  in  the 
open  air ;  the  object  being  to  separate 
carbonic  acid,  water,  sulphur,  and 
other  substances  volatile,  at  a  red 
heat.  The  operation  is  performed 
most  effectually,  and  probably  at  the 
smallest  cost,  in  kilns.  The  interior 
shape  of  the  calcining  kilns  differs  in 
different  works,  but  they  may  all  be 
reduced  to  that  of  the  common  lime 
kiln.  A  coal  fire  is  first  lighted  at 
the  bottom  of  the  kiln,  and  the  iron- 
stone is  placed  over  and  around,  until 
the  floor  is  covered  with  red  hot  ore ; 
a  fresh  layer  of  ironstone,  with  about 
5  per  cent,  of  coal,  is  then  laid  on,  to 
the  depth  of  8  or  9  inches;  and  when 
this  is  red  hot,  a  second  layer  is  added, 
and  so  on  gradually  till  the  kiln  is 
filled ;  by  the  time  this  is  done,  the 
lowermost  layer  is  cold  and  fit  to 
draw,  so  that  the  working  of  the  kiln 
is  a  continuous  operation.  When 
the  ore  is  calcined  in  the  open  air,  a 
heap  mingled  with  small  coal  (if 
necessary)  is  piled  up  over  a  stratum 
of  larger  pieces  of  coal,  the  heap  be- 
ing 5  or  6  feet  high,  by  15  or  20 
broad.  The  fire  is  applied  at  the 
windward  end,  and  after  it  has  burnt 
a  certain  way,  the  heap  is  prolonged 
at  the  other  extremity,  as  far  as  the 
nature  of  the  ground,  oi-  the  conven- 
ience of  work  requires.  From  the  im- 
possibility of  regulating  the  draught, 
and  from  exposure  to  the  weather, 
the  calcination  of  ore  cannot  be  so 
well  performed  in  the  open  air  as  in 
kilns;  and  as  to  the  relative  cost  of 
the  two  methods,  Mr.  Truran  calcu- 
lates that  the  quantity  of  coal  per  ton 
of  ore  is,  in  the  kiln,  one  hundred- 
weight of  small ;  and  in  the  open  air, 


IRON". 


631 


two  hundred-weights  of  small,  and  a  half  hundred-weight  of  large ;  and  that  while  the 
cost  of  filling  the  kiln  is  barely  a  penny  per  ton,  that  of  stacking  the  heaps  on  the  open 
air  plan,  and  watching  them  during  the  period  they  are  under  fire,  amounts  to  fourpence 
per  ton.  Against  this  must,  however,  be  placed  the  cost  of  erecting  the  kiln,  which  ac- 
cording to  the  same  authority  amounts,  for  a  kiln  of  a  capacity  equal  to  70  tons  of 
argillaceous  ore,  which  will  calcine  146  tons  weekly,  to  £160.  The  ironstone  loses  by 
calcining  from  25  to  30  per  cent,  of  its  weight ;  it  has  undergone  a  remarkable  change 
by  the  operation :  in  the  raw  state,  it  is  a  gray  or  light  brown  stony-looking  substance, 
not  attracted  by  the  magnet;  after  calcination  it  has  a  dry  feel,  adheres  strongly  to  tlie 
tongue,  is  cracked  in  all  directions,  is  of  a  light  reddish  color  throughout,  and  acts  pow- 
erfully on  the  magnet.  It  should  be  carried  to  the  furnace  as  soon  as  possible,  or  if  kept 
should  be  carefully  protected  from  the  rain. 

Flux. — The  only  flux  that  is  used  in  the  blast  furnace  is  limestone,  either  in  the  state 
of  carbonate  as  it  conies  from  the  quarry,  or  calcined  in  kilns,  by  which  it  is  deprived  of 
water  and  carbonic  acid.  The  lowest  bed  of  the  coal  formation  usually  rests  on  lime- 
stone, and  in  the  coal  formation  itself  are  found  not  only  the  ore  and  its  most  appropriate 
fuel,  but  the  pebbly  grits  which  afford  the  blocks  of  refractory  stone  necessary  for  build- 
ing those  parts  of  an  iron  furnace  that  are  required  to  endure  the  utmost  extremity  of 
heat,  as  well  as  those  seams  of  refractory  clay,  of  which  the  fire-bricks  are  composed, 
with  which  the  middle  and  upper  parts  of  the  furnace  are  lined.  "  Thus  many  situations 
in  this  favored  island  may  be  pointed  out,  in  which  all  the  above-mentioned  materials 
occur  almost  on  the  same  spot;  and  when  to  this  is  joined  the  convenience  of  water 
carriage,  as  happens  in  many  places,  that  man  must  indeed  be  of  an  obtuse  understand- 
ing and  a  churlish  temper  in  whom  this  wise  arrangement  and  prodigal  beneficence  of 
nature  fail  to  produce  corresponding  feelings." — Aikin. 

The  composition  of  the  limestone  to  be  used  in  smelting  operations  is  of  considerable 
importance;  where  calcareous  ores  are  used,  the  presence  of  silicic  acid  in  the  limestone 
is  advantageous;  if  clay  ores  are  the  main  material  from  which  iron  is  manufactured,  a 
magnesian  Hmestone  is  preferable,  but  an  aluminous  limestone  should  be  used  where 
silicious  ore  predominates.  Chemical  analysis  alone  can  determine  to  which  class  a  particu- 
lar limestone  belongs,  as  there  is  often  nothing  in  the  external  appearance  by  which  a  pure 
limestone  maybe  distinguished  from  one  containing  40  or  50  per  cent,  of  foreign  matter. 

Carbonized  pit-coal  or  coke  was,  till  within  the  last  twenty-five  years,  the  sole  combus- 
tible used  in  the  blast  furnace.  Coal  is  coked  either  in  the  open  air  or  in  kilns.  In  tlie 
former,  as  practised  in  Staifordshire,  the  coal  is  distributed  in  circular  heaps  about  5  feet 
in  diameter  by  4  feet  high,  and  the  middle  is  occupied  by  a  low  brick  chimney  piled  with 
loose  bricks,  to  open  or  to  leave  interstices  between  them,  especially  near  the  ground. 
The  larger  lumps  of  coal  are  arranged  round  this  chimney,  and  the  smaller  ones  towards 
the  circumference  of  the  mass.  Wlieu  every  thing  is  adjusted  a  kindling  of  coals  is  intro- 
duced into  the  bottom  of  the  brick  chimney,  and,  to  render  the  combustion  slow,  the 
whole  is  covered  with  a  coat  of  coal  dross,  the  chimney  being  loosely  covered  with  a  slab 
of  any  kind.  Openings  arc  occasionally  made  in  the  crust,  and  afterwards  shut  up,  to 
quicken  and  retard  the  ignition  at  pleasifre  during  its  continuance  of  twenty-four  hours. 
'Whenever  the  caibotiization  lias  reached  the  proper  point  for  forming  good  coke  the 
covering  of  coal  dross  is  removed,  and  water  is  thrown  on  the  heap  to  extinguish  the 
combustion — a  circumstance  deemed  useful  to  the  quality  of  the  coke.  In  this  operation 
ia  Staffordshire  coal  loses  the  half  of  its  weight,  or  two  tons  of  coal  produce  one  of  coke. 

In  order  to  prepare  larger  q\iantities  of  coke  at  once,  long  ridges  are  often  substituted 
for  circular  heaps,  the  length  of  which  varies  with  circumstances  and  the  consumption 
of  coke ;  they  sometimes  extend  to  the  length  of  200  feet.  On  erecting  one  of  these 
ridges  a  string  is  stretched  along  the  coking  station,  in  the  direction  of  which  large 
pieces  of  coal  are  placed  slanting  against  eacti  other,  leaving  a  triangular  space  between 
them,  so  that  a  longitudinal  channel  (ignition  passage)  is  formed  through  which  the  string 
passes.  In  arranging  the  pieces  it  is  necessary  to  pay  attention  to  the  natural  stratification 
of  the  coals,  which  should  be  at  right  angles  to  the  longitudinal  direction  of  the  ridge. 
Parallel  with  the  first  series  of  coals  is  placed  a  second,  and  then  a  third,  and  so  on  ;  but  the 
pieces  constantly  diminish  in  size  until  the  station  measures  6  feet  on  both  sides.  Upon 
this  substructure  the  heap  is  then  nuide,  without  particular  care  in  the  arrangements,  the 
largest  pieces  below  and  the  smallest  above,  until  it  has  reached  a  height  of  about  3  feet. 
To  facilitate  the  ignition,  stakes  are  rammed  in  at  distances  of  2  feet  from  each  other, 
projecting  above  throughout  the  whole  length  of  the  ridge,  which,  when  subsequently  re- 
moved, leave  vacant  spaces  for  the  introduction  of  burning  coal.  The  ridge,  being  thus 
kindled  at  more  than  1(J0  distinct  spots,  soon  breaks  out  into  active  combustion.  As  soon 
as  the  burner  observes  the  thick  smoke  and  flame  cease  at  any  one  part,  and  a  coating 
of  ash  making  its  appearance,  he  endeavors  immediately  to  stop  the  progress  of  the  fire 
by  covering  it  with  powdered  coal  dust,  repeating  the  operation  until  the  whole  ridge  is 
covered,  wlien  it  is  left  two  or  three  days  to  cool ;  the  covering  on  the  side  exposed  to  the 


632 


IRON. 


wind  should  be  thicker,  and  increased  in  stormy  weather.  When  the  fire  is  nearly  ex- 
tinguished, which  occurs  in  two  or  three  days,  the  coke  is  drawn.  This  mode  of  coking 
is  simple,  but  not  very  economical.  The  lire  proceeding  from  the  upper  part  of  the  ridge 
in  a  downward  direction,  towards  the  lower  and  interior  parts,  converts  the  coal  in  the 
upper  strata  into  coke  before  that  in  the  interior  has  acquired  the  temperature  necessary 
for  charring,  and  is  still  in  want  of  a  supply  of  air,  which  can  only  be  furnished  from  with- 
out and  must  not  be  excluded  by  a  covering.  During  the  time,  therefore,  that  the 
inner  parts  of  the  heap  are  being  converted  into  coke,  the  outer  portions  are  being  use- 
lessly, though  unavoidably,  consumed.     See  the  articles  Co.\l  and  Coke. 

The  "  blowing  in  "  of  a  coal  blast  furnace  is  an  operation  which  requires  much  care  and 
experience.  A  tire  of  wood  is  first  lighted  on  the  hearth  ;  upon  this  is  placed  a  quantity 
of  coke,  and  when  the  Avhole  is  well  ignited,  the  furnace  is  filled  to  the  throat  with  regular 
charges  of  calcinevl  ore,  limestone,  and  coke,  and  the  blast,  which  should  at  first  be  mod- 
erate, is  turned  on.  At  the  works  around  Merthyr  Tydvil,  the  first  charges  generally  con- 
sist of  5  cwts.  of  calcined  argillaceous  ore  and  If  cwts.  limestone,  to  4  cwts.  of  rich 
coke ;  this  burden  is  kept  on  for  about  10  days ;  it  is  then  increased  to  6  cwts.  of  cal- 
cined ore  and  2^  cwts.  of  limestone. — (Tntraii.)  The  cinders  usually  make  their  ap- 
pearance in  about  12  hours  after  blowing,  the  metal  follows  in  about  10  hours  after,  col- 
lecting in  the  hearth  to  the  amount  of  3  or  S^  tons  in  60  hours  after  blowing.  If  all 
goes  on  well  about  22  tons  of  metal  will  be  produced  in  the  first  week,  38  tons  in  the  sec- 
ond, 55  in  the  third,  and  nearly  80  in  the  fourth  ;  after  10  or  12  weeks  the  produce  will 
average  110  tons.  By  forcing  the  furnace  in  its  infancy,  a  much  greater  produce  of  iron 
may  be  obtained,  though  to  the  injury  of  its  subsequent  working.  Mr.  Truran  relates  the 
following  case  in  point: — A  furnace  was  blown  in  at  the  Abersychan  works  with  such  vol- 
umes of  blast  and  rich  burden  of  materials  that  a  cast  of  several  tons  was  obtained  within 
14  hours  after  applying  blast.  The  first  week's  blowing  produced  200  tons,  at  which  rate  it 
continued  for  two  or  three  weeks,  when  it  rapidly  diminished,  falling  so  low  jis  19  tons  for 
one  week's  make.  From  this  deplorable  state  it  was  made  to  produce  26  tons,  and,  after 
considerable  delay,  100  tons;  but  with  a  large  increase  in  the  yield  of  materials  over  that 
at  the  other  furnaces.  When  a  furnace  is  first  blown  in  it  should  be  made  to  produce  gray 
iron  ;  but  the  tendency  of  forcing  is  to  produce  a  white  iron  with  a  dark  scouring  cinder. 

The  quantity  of  air  thrown  into  a  blast  furnace  in  full  work  is  enormous,  exceeding  in 
weight  the  totals  of  all  the  soiled  materials  used  in  smelting.  A  furnace  working  on  foun- 
dry iron  of  a  capacity  of  275  yards  receives  5,390  cubic  feet  of  air  per  minute,  which 
amounts  weekly  to  1,695  tons  ;  when  working  on  white  iron  a  larger  volume  of  blast  is  em- 
ployed, averaging  "7,370  cubic  feet  per  minute,  or  2,318  tons  per  week. 

The  disorders  to  which  blast  furnaces  are  liable  have  a  tendency  to  produce  white  cast 
iron.  The  color  of  the  slag  or  scoriaj  is  the  surest  test  of  these  derangements,  as  it  indi- 
cates the  quality  of  the  products.  If  the  furnace  is  yielding  an  iron  proper  for  casting  into 
moulds,  the  slag  has  an  uniform  vitrification  and  is  slightly  translucid.  When  the  dose  of 
ore  is  increased  the  slag  becomes  opaque,  dull,  and  of  a  greenish  yellow  tint,  with  blue 
enamelled  zones.  Lastly,  when  the  furnace  is  producing  white  metal,  the  slags  are  more  or 
less  black  and  glossy.  The  scorise  from  a  coke  :fre  much  more  loaded  with  lime  than  those 
from  a  charcoal  blast  furnace.  This  excess  of  lime  appears  adapted  to  absorb  and  carry  off 
the  sulphur  which  would  otherwise  injure  the  quality  of  the  iron.  From  numerous  analyses 
we  have  made  of  blast  furnace  cinders  we  select  the  following  as  illustrating  their  general 
composition  under  different  conditions  of  the  furnace  : — 

Analyses  of  Blast  Furnace  Cinders.     (Dr.  Noad.) 


Silica  .  .  .  - 
Alumina  ... 
Lime  .... 
M.iffnosia  ... 
Protosiflc  of  manganese 
Protoxide  of  iron 
Potash  -  -  .  . 
Sulphuret  of  calcium  - 
Loss      .... 


n. 


in. 


40-20 
17  00 

so-u 

7-16 
traces 
1-90 
1-26 
1-70 
•43 


3S-49 

14-12 

34-35 

6-14 

1-54 

2-10 

1-4S 

116 

•62 


41-13 

22-00 

29-43 

1-83 

traces 

3-60 

not  determined 

1-09 


100-00      100-00 


100-00 


IV. 


TL 


VIL 


40-50 
12-43 
26-55 
3-20 
11-20 
3-20 
1-15 
2-20 
•52 


49-40 
21 -OS 
17  56 
4-96 
1-04 
3-60 
•87 

!■  1-49 


40-56 
27-33 
10-30 

2-75 

2-00 
1312 

1-90 
•46 

158 


42-96 
'  20-20 
I  10-19 
2-90 
1-53 
i  19-80 
I     1-10 


1-82 


100-00     1 100-00     IIOO^OO      100^00 


I.  Mean  of  four  analyses  of  ?ray  iron  cinders  from  a  furnace  at  Blaina.  South  "Wales.  II.  Mean  of 
four  analyses  of  eray  iron  cinders  from  an  iron  work  in  Stafiordsliiro.  III.  Mean  of  four  analyses 
of  cr.ay  iron  (cold  blast)  cinders  from  Pontypool,  South  Wales.  lY.  Mean  of  four  analyses  of  green 
cinder  from  a  furnace  at  Ebbw  Vale,  Monmouthshire,  smelting  spathose  ore.  V.  Mean'of  four  an.il- 
yses  of  blast  furnace  cinders  from  Sweden.  VI.  Mean  of  four  analyses  of  white  iron  cinder  from 
a  furnace  at  Cwm  Celyn  Iron  AVorks,  Monmouthshire.  VII.  Mean  of  four  analyses  of  white  iron 
cinder  from  the  s.amo  works,  the  furnace  "scouring.""  '  i 


IROK 


633 


The  following  table  exhibits  the  "  yields  "  of  materials  per  ton  on  the  iron  made  in 
various  works.  During  the  month  endmg  July  25th,  1857,  there  were  consumed  in  four 
furnaces  at  Ebbw  Vale  1,354  tons  11  cwt.  of  coke  ;  1,792  tons  of  coal ;  2,440  tons  19  cwt. 
of  calcined  mine;  1,818  tons  10  cwt.  of  red  ore;  1,347  tons  6  cwt.  of  calcined  cinders; 
and  1,226  tons  7  cwt.  of  burnt  lime.  The  quantity  of  pig  iron  made  was  2,305  tons 
7  cwt.  : — 

Yields  of  Materials  per  Ton  of  Iron. 


Calcined  mine  ■ 
Hsomatite 
Cinders    - 

Coal 

Limestone 


1    I. 

II. 

III. 

IV. 

V. 

cwt. 

cwt. 

cwt. 

cwt. 

cwt. 

48 

2S 

0 

46 

33 

0 

10 

10 

0 

0 

0 

10 

25 

0 
coke 

0 

50 

42 

3G 

84 

40 

IT 

14 

16 

16 

5 

VI.      VII. 


cwt. 

27 
10 
0 
coke 
34 
15 


cwt. 

21 

]f.f 

Hi 

34 
13 


VIII. 


Hi 


4i 


IX. 

cwt. 

0 


ISJ 


I.  Dowlais  foundry  iron.     II.   Dowlais  forge  iron.     III.  Dowlais  iiifi-rior  forge  inin.     IV.  Ilirwain 
foundry  iron.     V.    Dunrtyvan,  Scotland,  foundry  iron.     VI.    I'ontyiiool  cold  blast  foundry  iron.  | 
VII.  Ebbw  Vale  forge  iron.     VIII.  Owm  Celyn  forge  iron.     IX.  Coalbrook  Vale  foundry  iron.         | 

The  "  cinders  "  mentioned  in  the  foregoing  table  are  not  those  from  the  blast  furnace, 
but  are  derived  from  the  cast  iron  during  the  processes  of  "  refining,"  "  puddling,"  &c.,  by 
which  the  cast  iron  is  converted  into  wrought  iron.  These  cinders  are  very  rich  in  iron, 
which  exists  in  them  principally  in  the  form  of  silicate  of  the  protoxide.  They  often  occur 
beautifully  crystallized,  particularly  after  they  have  been  calcined — an  operation  which  is 
always  performed  on  them  in  well-conducted  works,  and  which  has  for  its  object  the  re- 
moval of  the  sulphur  and  the  peroxidation  of  a  portion  of  the  iron.  The.-^e  cinders,  though 
very  rich  in  iron,  are  always  contaminated  to  a  considerable  extent  with  both  sulphur  and 
phosphorus,  as  might  be  expected,  seeing  that  they  are  the  results  of  operations  which  have 
for  their  objects  tlie  removal  of  the  foreign  matters  contained  in  the  pig  iron.  The  ten- 
dency of  the  former  is  to  make  the  metal  what  is  called  "  hot  short,"  so  that  it  cannot  be 
worked  while  hot  under  the  hammer ;  the  tendency  of  the  latter  element  is  to  make  the 
iron  "  cold  short,"  so  that  it  breaks  when  an  attempt  is  made  to  bend  it  when  cold.  The 
separation  oF  sulphur  is  very  perfectly  effected  by  the  calcination  of  the  cinder,  and  it  is 
interesting  to  trace  the  progress  of  its  gradual  elimination.  In  some  parts  of  the  he;ip 
(which  often  contains  several  thousand  tons  of  cinder)  large  masses  of  prismatic  crystals  of 
pure  sulphur  may  be  found,  but  usually  nearly  the  entire  surface  of  the  heap  is  covered 
with  a  thin  layer  of  sulphate  of  iron,  sometimes  cr3"stallized,  but  generally  in  various  stages 
of  decomposition  ;  lower  down  in  the  heap,  where  the  heat  is  greater,  the  sulphate  of  iron 
disappears,  and  in  its  place  red  oxide  of  iron,  without  a  trace  of  sulphur,  is  found.  In  cal- 
cining a  heap  of  cinders  care  is  required  not  to  allow  the  heat  to  rise  too  high,  or  immense 
masses  will  become  melted  together,  involving  the  necessity  of  blasting,  which  entails  much 
expense.  After  the  heap  has  been  burningfor  some  months,  streams  of  water  are  directed 
over  the  surface,  by  which  much  soluble  sulphate  of  iron  is  removed.  Unfortunately,  the 
process  of  calcination  does  not  remove  any  of  the  phosphoric  acid,  which  necessitates  a  judi- 
cious employment  of  these  cinders  in  the  blast  furnace.  We  have  repeatedly  submitted 
"  forge  cinders"  to  analysis,  and  give  in  the  following  table  the  average  results  of  our  ex- 
periments : — 

Analyses  of  Forge  Cinders.     (Dr.  Noad.) 


I.        1        IL                   IIL 

IV. 

•    V. 

VL 

Silica  ...        - 

6-0'0 

6-67 

32-000 

15-30(1 

]2-.'?00 

12-sno 

Protoxide  of  iron 

63-750 

72-60 

52  200 

51-7-20 

67-360 

10-500 

Peroxide  of  inm 

11-420 

6-30 

5-000 

19-980 

2-S50 

70-000 

Siilphuret  of  iron 

6-766 

4-56 

1-953 

5-396 

5-600 

•620 

Oxide  of  manganese  - 

1-680 

1-77      not  determined 

-960 

not  deternaned 

1-140 

Alumina     -        -        - 

2-400 

2-22                 9 -COO 

1-300 

r.-eoo 

-427 

Lime  .        .        -        - 

1-232 

•12               traces 

•420 

traces 

traces 

Magnesia     -        -        - 

traces 

traces               traces 

traces 

traces 

traces 

Phosi)lioric  acid  - 

7-208 

5-36                   -252 

4-140 

6-820 

4-500 

99-516     i      9960     1        101-105 

99-216 

100-030 

99-987 

I.  Tap  cinder  from  roflnt 

d  metal.     II.  Tap  cinder  from  pnddlin 

g  furnace. 

in.  Cinder  fi-om 

reheat- 

ing  fiirn.ico.     IV.  Mix( 

>d  cinder  from  the  heap  after  a  few  da 

vs'  burning 

.     V.  Cinder  squeezed  out 

of  the  pudilHng  bar  dur 

ing  the  process  of  shingling.     VI.  Spec 

inien  from 

a  largo  heap  of  thoroughly 

calcined  cinder. 

1 

The  experiments  through  which  Mr.  Nielsen's  important  discovery  of  the  hot  blast  was 
introduced  into  the  iron  manuf\icfure,  were  made  at  the  Clyde  Iron  Works,  where  the  fuel 


634  IKON. 

generally  made  use  of  was  coke,  derived  from  splint  coal ;  during  its  conversion  into  coke, 
this  coal  sustained  a  loss  of  55  per  cent.  During  the  first  six  months  of  the  year  1829, 
when  all  the  cast  iron  in  the  Clyde  Iron  Works  was  made  by  means  of  the  cold  blast,  a 
single  ton  of  cast  iron  required  for  fuel  to  reduce  it  8  tons  1;^  cwt.  of  coal,  converted  into 
coke.  During  the  first  six  months  of  the  following  year,  while  the  air  was  heated  to  near 
300°  F.,  1  ton  of  cast  iron  required  5  tons  'S^  cwt.  of  coal  converted  into  coke.  The  sav- 
ing amounts  to  2  tons  18  cwt.  per  ton  of  iron,  from  which  must  be  deducted  the  coal  used 
in  heating  the  air,  which  was  nearly  8  cwt.  This  great  success  induced  the  Scotch  iron 
masters  to  try  a  higher  temperature,  and  to  substitute  raw  coal  for  coke ;  and  during  the 
first  six  months  of  the  year  1833,  the  blast  being  heated  to  600°,  1  ton  of  cast  iron  was 
made  with  2  tons  5^  cwt.  of  coal.  Add  to  this  8  cwt.  of  coal  for  heating,  and  we  have  2 
tons  13:^  cwt.  of  coal  to  make  one  ton  of  iron.  An  extraordinary  impetus  was  given  by 
this  discovery  to  the  iron  manufacture  in  Scotland,  where,  from  the  peculiar  nature  of  tlie 
coal,  and  from  the  circumstance  that,  with  a  heated  blast,  Mushet's  blackband  ironstone 
could  be  exclusively  used,  its  importance  was  more  highly  felt  than  in  England  and  \Valcs. 
According  to  Mr.  Finch's  statement,  (Scrivenor's  "  History  of  the  Iron  Trade,")  there  were 
in  1830  only  eight  works  in  operation  in  Scotland,  which  made  in  that  year  37,500  tons  of 
pig  iron;  in  1838  there  were  eleven  works,  consisting  of  41  furnaces,  which  made  147,500 
tons,  being  an  increase  in  eight  years  of  110,000  tons  per  annum  ;  in  1839,  there  were  50 
furnaces  in  blast,  making  195,000  tons ;  in  1851,  750,000  tons  of  pig  iron  were  made  ;  and 
in  1856,  with  127  furnaces  in  blast,  the  make  rose  to  880,500  tons.  The  influence  of  hot 
blast  has  likewise  been  felt  in  the  anthracite  district  of  South  Wales,  where  that  coal  is  now 
successfully  used,  and  where  several  furnaces  have  in  consequence  been  erected.  In  short, 
notwithstanding  tlie  opposition  with  which  the  introduction  of  hot  blast  was  met  by  en- 
gineers, as  being  destructive  of  the  quality  of  the  iron,  so  great  have  been  the  advantages 
derived  from  it,  that  at  the  present  time  more  than  ninetecn-twentieths  of  the  entire  pro- 
duce of  the  kingdom  is  made  in  furnaces  blown  with  heated  air. 

Mr.  Truran,  in  his  recent  work  on  the  iron  manufacture  of  Great  Britain,  gives  it  as  his 
opinion  that  the  effects  of  hot  blast  have  been  greatly  exaggerated,  and  that  it  is  to 
improvements  in  the  preparation  of  fuel  and  ore  in  the  furnaces,  in  blowing  engines,  and 
in  the  smelting  process,  far  more  than  to  the  heating  of  the  blast,  that  we  must  refer  the 
great  reduction  in  the  yields  of  coal  in  recent  times  ;  he  thinks  that  the  comparatively  large 
produce  which  has  been  obtained  from  the  Scotch  furnaces,  is  to  be  referred  to  the  general 
use  of  carbonaceous  ore,  which  melts  at  a  low  temperature,  and  which,  from  its  compar- 
ative freedom  from  earthy  matters,  requires  but  a  minimum  dose  of  limestone  for  flux- 
ing. Against  this  opinion  of  an  English  writer  on  iron  smelting  we  may  place  that  recorded 
by  an  American  metallurgist,  Mr.  Overman,  who  has  written  a  large  and  in  many  respects  a 
valuable  treatise  on  the  manufacture  of  iron,  as  conducted  in  America.  "  The  economical 
advantages  arising  from  the  application  of  hot  blast,  casting  aside  those  cases  in  which  cold 
blast  will  not  work  at  all,  are  immense.  The  amount  of  fuel  saved  in  anthracite  and  coke 
furnaces  varies  from  SO  to  60  per  cent.  In  addition  to  this,  hot  blast  enables  us  to  obtain 
nearly  twice  the  quantity  of  iron  within  a  given  time  tliat  we  should  realize  by  cold  blast. 
These  advantages  are  far  more  striking  with  respect  to  anthracite  coal  than  in  relation  to 
coke  or  to  bituminous  coal.  By  using  hard  charcoal,  we  can  save  20  per  cent,  of  fuel,  and 
augment  the  product  50  per  cent.  From  soft  charcoal  we  shall  derive  but  little  benefit,  at 
least  where  it  is  necessary  to  take  the  quality  of  the  iron  into  consideration." 

The  following  tables,  embodying  the  general  results  of  an  extended  series  of  experi- 
ments on  the  relative  strength  and  other  mechanical  properties  of  cast  iron,  obtained  by  the 
hot  and  cold  blasts,  are  extracted  from  a  report  presented  to  the  British  Association  (1837) 
by  Messrs.  Eaton,  Hodgkinson,  and  William  Fairbairn. 

Of  the  three  columns  of  numbers,  the  first  represents  the  strength  or  other  quality  in  the 
cold  blast  iron,  the  second  that  in  the  Iiot,  the  third  is  the  ratio  of  these  qualities ;  the  fig- 
ures included  in  parentheses,  indicate  the  number  of  experiments  from  which  the  results 
have  been  deduced. 

These  results  contain  nearly  the  whole  of  the  information  afforded  by  the  investigation. 
From  the  numbers  in  the  tables,  it  will  be  seen  that  in  Buffcry  iron  No.  1,  cold  blast  some- 
what surpasses  hot  blast  in  all  the  following  particulars  :—l,  direct  tensile  strength  ;  2, 
compressive  strength  ;  3,  transverse  strength  ;  4,  power  to  resist  impact ;  5,  modulus  of 
elasticity  or  stiffness  ;  6,  specific  gravity  ;  while  the  only  numerical  advantage  possessed  by 
the  hot  blast  metal  is  that  it  bends  a  little  more  than  the  cold  before  it  breaks.  In  No.  2 
the  advantages  of  the  rival  kinds  are  more  nearly  balanced,  still  rather  in  favor  of  the  cold 
blast.  No.  3  hot  blast  Carron  iron  resists  both  tension  and  compression  better  than  cold 
blast  of  the  same  denomination  ;  and  No.  3  hot  blast  from  the  Devon  works  in  Scotland  is 
remarkably  strong,  while  No.  3  cold  blast  is  comparatively  weal<,  notwithstanding  its  high 
specific  gravity.  On  the  whole  it  would  appear  from  the  experiments,  that  while  the  irons 
of  No.  1  have  been  somewhat  deteriorated  in  quality  by  the  hot  blast,  those  of  No.  3  have 
been  benefited  by  its  mollifying  powers ;  while  those  of  No.  2  have  been  but  very  slightly 


IRON. 


635 


affected  ;  and  from  the  evidence  brought  forward,  it  is  rendered  highly  probable  that  the 
introduction  of  a  heated  blast,  while  it  has,  perhaps,  to  a  certain  extent,  injured  the  softer 
irons,  lias  improved  those  of  a  liarder  nature  ;  and  considering  the  small  deterioration  that 
the  irons  of  the  quality  No.  2  have  sustained,  and  the  apparent  benefit  of  those  of  No.  3, 
together  with  the  saving  effected  by  the  heated  blast,  there  seems  good  reason  for  the  pro- 
cess becoming  so  general  as  it  has  done. 


Carron  Iron,  No.  2. 
Tensile  strength  in  lbs.  per  square  inch 
Compressive  streQgth  in  lbs.  per  inch,  from  cast- 
inijs  torn  asunder        .----- 

Ditto,  from  prisms  of  various  forms     -        .        - 
Ditto,  from  cylinders     -        -      .  - 
Transverse  strength  from  all  experiments    - 
Power  to  resist  impact  ------ 

Transverse  strength  of  bars  one  inch  square  in  lbs. 
Ultimate  deflection  of  do.  in  inches      .        -        - 
Modulus  of  elasticity  in  lbs.  per  square  inch 
Specific  gravity      ...---- 

Devon  Iron,  No.  3. 
Tensile  strength    .        .        -       -        ... 
Compressive  strength    ------ 

Transverse  do.  from  experiments  generally 
Power  to  resist  impact  ------ 

Transverse  strength  of  bars  one  inch  square 

Ultimate  deflection  do. 

Modulus  of  elasticity     ------ 

Specific  gravity     ------- 

Coed  Talon  Iron,  No.  2. 
Tensile  strength     ..----- 

Compressive  strength    -         -        -        -        -        - 

Specific  gravity      -        -        -        .        .        .        - 

Carron  Iron,  No.  3. 
Tensile  strength     .---•-- 
Compressive  strength    -        -        -        .        .        - 
Specific  gravity      ..--•-- 

BuFFERY  Iron,  No.  1. 

Tensile  strength -        - 

Compressive  strength    ------ 

Transverse  strensth       ...... 

Power  to  resist  impact  --.--. 
Transverse  strength  of  bars  one  inch  square 
Ultimate  deflection  do.  ------ 

Modulus  of  ela.sticity 

Specific  gravity     ------- 


16,6S3  (2) 

106,375  (3) 
100,631  (4) 
125,403  (13) 

-  -  (11) 

-  -   (9) 
476  (3) 

1-313    (3) 
17,270,500    (2) 
7,066 


-  -  (5) 

-  -  (4) 
448  (2) 

-79  (2) 

22,907,700  (2) 

7,295  (4) 


18,8.55     (2) 

81,770     (4) 

6,955    (4) 


14,200     (2) 

115,542    (4) 

7,135    (1) 


17,466  (1) 

93,366  (4) 

-  -  (5) 

-  -  (2) 
463  (3) 
1-55  (3) 

15,331,200  (2) 
7,079 


Ratio,  representing 
Cold  lilnst  by  KKiO. 


13,505  (3)  I  1000  :  809 

103,540  (2)  I  1000:1020 

100,733  (2)  i  1000  :  lool 

121,085  (13)  I  1000 :  970 

-  (13)  j  1000  :  991 

(9)  1000 :  1005 

463  (3)  1000:  973 

1-337  (3)  1000 :  1018 

16,085,000  (2)  1000:  931 

7,046  1000:   897 


11^ 


21,907  (1) 

145,435  (4) 

-  -  (5) 

-  -  (4) 
537  (2) 

109  (2) 

22,473.650  (2) 

7,229  (2) 


16,676    (2) 

82.7.39     (4) 

0,968    (4) 


17,755    (2) 

133,440    (3) 

7,056    (1) 


1.3,434  (1) 

86,397  (4) 

-  -  (5) 

-  -  (2) 
436  (3) 

164  (3) 

1-3,730,500  (2) 
6,958 


1000 :  1417 
1000 :  2786 
1000:  1199 
1000 ;  1380 
1000  :  981 
1000:    991 


1000:  884 
1000  :  1012 
1000  :  1002 


1000  :  1250 
1000  :  11.56 
1000:    989 


1000  :  769 

1000:  9-25 

1000:  931 

1000:  963 

1000:  942 
1000 :  1053 

1000:  893 

1000:  989 


The  following  general  summary  of  results,  as  derived  from  the  experiments  of  Messrs. 
Hodgkinson  and  Fairbairn  on  the  transverse  strength  of  hot  and  cold  blast  iron  exhibits  at 
one  view  the  ultimatum  of  the  whole  investigation. 


R.atioof  Stronsth 
—that    of    Cold 
Blast  being  rep- 
resented by  1000. 

Ratio  of  Powers 
to    sust.ain    Im- 
pact—Cold  Blast 
being  1000. 

These  irons  are  from  Mr.  Hodgkinson's  experiments : — 
Carron  iron.  No.  2    ------         - 

Devon  iron,  No.  3------- 

Buffery  iron,  No.  1 

These  irons  arc  from  Mr.  Fairbairn's  experiments : — 

Coed  Talon  iron.  No.  2 

Coed  Talon  ditto,  No.  3 

Elsicar  and  Milton,  ditto  ------ 

Carron  ditto.  No.  3 

Muirkirk,  No.  1         .-....- 

Mean        -.....- 

1000  :    990-9 
1000  :  1416-9 
1000  :    930-7 

1000  :  1007 
1000  :    927 
1000  :     818 
1000  :  1181 
1000  :    9'27 

1000  :  1005-1 
1000  :  2785-6 
1000:    962-1 

1000  :  1234 
1000  :    925 
1000  :    875 
1000  :  1201 
1000  :    823 

1000  :  1021-8 

1000  :  1226-3 

Dr.  Thomp.son's  chemical  examination  of  several  samples  of  hot  and  cold  blast  iron  is 
appended  to  this  report.  According  to  the  experiments  of  this  distinguished  chemist,  iron 
smelted  by  hot.  blast  contains  a  greater  proportion  of  iron,  and  a  smaller  proportion  of  silicon, 
carbon,  and  aluminum,  tlian  when  smelted  by  cold  air.     The  mean  specific  gravity  of  8  speci- 


636 


IRON. 


mens  of  Scotch  cold  blast  iron  No.  1,  was  6-7034  ;  the  mean  of  5  specimens  of  hot  blast 
from  the  Carron  and  Clyde  iron  works  was  7.0623,  so  that  the  density  of  cold  blast  iron  is 
less  than  that  of  hot.  The  mean  of  6  analyses  of  cold  blast  iron  No.  1,  gave  3^  atoms  of 
iron,  1  atom  of  carbon,  silicon,  and  aluminum  ;  the  proportion  of  these  three  constituents 
being  very  nearly  4  atoms  of  carbon,  1  atom  of  silicon,  and  1  atom  of  aluminum ;  conse- 
cjuently  Scotch  cold  blast  iron  consists  of  20  atoms  of  iron,  (with  a  little  manganese,)  4 
atoms  of  carbon,  1  atom  of  silicon,  and  1  atom  of  aluminum.  The  mean  of  5  analyses  of 
hot  blast  iron  No.  1,  gave  6i  atoms  of  iron  and  manganese  to  1  atom  of  carbon,  silicon,  and 
aluminum,  from  which  it  would  appear  that  cast  iron  smelted  with  a  heat  blast  is  purer  than 
when  the  blast  is  cold.  This,  however,  is  not  the  case,  as  the  numerous  analyses  of  both 
varieties  that  have  been  made  during  the  last  few  years  concur  in  proving.  Hot  blast  gray 
iron  smelted  with  mineral  coal  contains  a  much  higher  percentage  of  silicon  than  the  same 
variety  of  cast  iron  smelted  from  the  same  ores  by  cold  blast ;  in  other  respects,  provided 
the  process  of  reduction  is  complete,  i.  c.  when  little  or  no  iron  passes  off  with  the  slag, 
there  is  very  little  chemical  difference  between  the  two  varieties,  as  will  be  seen  in  the  fol- 
lowing table,  which  contains  the  results  of  a  series  of  analyses  of  hot  and  cold  blast  iron, 
which  we  have  lately  had  occasion  to  make,  under  circumstances  peculiarly  favorable  for 
instituting  the  comparison,  the  furnaces  working  with  the  same  ores,  and  making  the  same 
class  of  iron,  viz.  good  No.  3  gray  pig. 

Analyses  of  Cast  Iron  No.  3,  smelted  by  Hot  Blast.     (Dr.  Noad.) 


I. 

II.      1     III.            IV. 

V. 

VI. 

VII. 

VIII. 

llenn. 

Silicon      ... 
Graphite  ... 
Sulpbar    - 
Phosphorus      - 

Met! 

2-500 
3-5-20 
0-045 
0-313 
illic  iron 

3-140    I    3-380 
3-100        3-210 
0-090        0-079 
0-422        0-308 
per  cent. 

2-440 
3-102 
0-069 
0-394 

3-200 
3.340 
0-072 
0-422 

3-190 
3-320 
0046 
0-4S0 

8-120 
3-340 
0-072 
0-320 
93-15 

2-260 
3294 
0  064 
0-374 

2  900 
3-290 
0-067 
0-379 

Analyses  of  Cast  Iron  No.  3,  smelted  by  Cold  Blast.     (Dr.  Noad.) 


Silicon 
Graphite  - 
Sulphur    - 
Phosphorus 


I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

VIII. 

Mean. 

1-0.10 
3-370 
0-024 
0-210 

llic  iron 

1-400 
3-1S4 
0-037 
0-314 
per  cent. 

1-029 
3-270 
0-045 
0-387 

0-940 
3-140 
traces 
0-361 

1-372 
3-333 
0-029 
0-372 

1-486 
3-274 
0-037 
0-872 

1-466 
3-242 
0-028 
0-342 
90-0 

1-400 
3-197 
0  024 
0-354 

1-268 
3251 
0028 
0-339 

The  true  reason  of  the  frequent  inferiority  of  hot  blast  iron  has  been  correctly  given  by 
Mr.  Blackwell.  Furnaces  blown  with  heated  air  exert  greater  reductive  power  than  those 
in  which  a  cold  blast  is  used.  This  has  led,  since  the  introduction  of  hot  blast,  to  the  ex- 
tensive use  in  iron  smelting  of  refractory  ores  not  formerly  smelted,  a  large  part  of  which 
have  been  ores  of  a  class  calculated  to  produce  inferior  iron,  and  it  is  to  the  use  of  ores  of 
this  nature,  far  more  than  from  any  deterioration  in  quality,  arising  from  a  heated  blast, 
that  this  inferiority  of  hot  blast  iron  is  to  be  ascribed. 

Utilization  of  the  waste  gases  given  off  from  the  furnace  head. — The  agent  in  the  blast 
furnace  by  which  the  oxide  of  iron  is  reduced,  is  carbonic  oxide,  the  presence  of  which, 
therefore,  in  great  excess  is  indispensable  to  the  operation  of  the  furnace.  The  flames 
rising  from  the  tunnel  head,  which  make  a  blast  furnace  at  night  such  an  imposing  object, 
are  occasioned  principally  by  the  combustion  of  this  gas,  on  coming  into  contact  with  the 
oxygen  of  the  atmosphere  ;  the  attention  of  practical  men  was  first  called  to  the  enormous 
waste  of  heat  which  this  useless  flame  entailed  by  Messrs.  Bunsen  and  Playfair,  and  the 
application  of  the  gas  to  a  useful  purpose  may  be  ranked  noxt  to  that  of  the  heated  blast,  :is 
the  most  important  of  the  recent  improvements  in  the  iron  manufacture.  The  gases  evolved 
from  iron  furnaces  where  coal  is  used  as  the  fuel,  contain  the  following  constituents,  viz. : 
nitroge?i,  ammonia,  carttouic  acid,  carbonic  oxide,  light  carbiirettcd  hydrogen,  ohfiant  gas, 
ciirburetted  hydrogen  of  unknown  composition,  hydrogen,  sulphuretted  hydrogen,  and 
n//neons  vapor.  The  nature  of  the  combustible  gas  stands  in  a  relation  so  intimate  to  the 
(hanges  suffered  by  the  materials  put  into  the  furnace,  that  its  different  composition  in  the 
various  reigons  of  the  furnace  indicates  the  changes  suffered  by  the  materials  introduced  as 
tlicy  descend  in  their  way  to  the  entrance  of  the  blast.  Now  as  the  examination  of  this 
column  of  air  in  its  various  heights  in  the  furnace  must  be  the  key  to  the  questions  upon 
which  the  theory  and  practice  of  the  manufacture  of  iron  depend,  it  was  of  the  first  im- 
portance to  subject  it  to  a  rigid  examination  ;  this  accordingly  has  been  done  by  the  above- 
named  eminent  chemists,  and  subsequently  by  Ebclmen.  We  shall  return  to  a  consiikra- 
tion  of  the  results  they  obtained  presently,  confining  our  attention  at  present  to  the  compo- 
sition of  the  gases  at  the  mouth  of  the  furnace,  and  to  the  methods  which  have  been 
adopt<'(l  to  utilize  them. 


lEOX.  637 

In  order  to  arrive  at  a  knowledge  of  the  composition  of  these  gases,  M.  Bunsen  first 
studied  minutely  the  phenomena  which  would  ensue  were  the  furnace  filled  with  fuel  only  : 
by  a  careful  distillation  of  a  linown  weight  of  coal,  and  analyzing  of  the  products,  he  ob- 
tained results  embodied  in  the  subjoined  table  : — 

Carboii 68-925 

Tar -         -       12-230 

Water 7-569 

Light  carburetted  hydrogen  -         -         -         -         -         7-021 

Carbonic  oxide 1-135 

Carbonic  acid  ....----  1-073 
Condensed  hydrocarbon  and  olefiant  gas  -  -  -  0-753 
Sulphuretted  hydrogen         .--..-         0-549 

Hydrogen 0-499 

Ammonia 0-211 

Nitrogen 0-035 

100-000 
Now,  in  the  furnace,  the  oxygen  introduced  by  the  blast  is  consumed  in  the  immediate 
vicinity  of  the  tuyere,  being  there  converted  into  carbonic  oxide,  and  the  coal  loses  all  its 
gaseous  products  of  distillation  much  above  the  point  at  which  its  combustion  commences, 
near  in  fact,  the  top  of  the  furnace ;  the  fuel  with  which  the  blast  comes  into  contact  is, 
therefore,  colce,  and  upon  calculating  the  amount  of  carbonic  oxide  produced  by  the  com- 
bustion of  68-925  per  cent,  of  carbon,  and  the  nitrogen  of  the  air  expended  in  the  combus- 
tion, we  get  as  the  composition  by  volume  of  the  gases  escaping  from  a  furnace  filled  with 
Gasforth  coal  the  following  : — 

Nitrogen 62-423 

Carbonic  oxide     -.-----•       33-163 

Light  carburetted  hydrogen 2-527 

Carbonic  acid       .-..----         0*139 

Condensed  hydrocarbon 0-151 

Sulphuretted  hvdrogen 0-091 

Hydrogen    -    " 1-431 

Ammonia     --         ....---        0-070 


100-000 
With  this  preliminary  information,  Bunsen  proceeded  to  calculate  the  modification  of 
the  gaseous  mixture  occasioned  by  the  introduction  into  the  furnace  of  iron  ore  and  lime- 
stone.    The  materials  used  for  the  production  of  140  lbs.  of  pig-iron  were  : — 

420  lbs.  calcined  iron  ore  ;  390  lbs.  coal ;  170  lbs.  limestone.  From  100  parts  of  the 
coal,  67-228  parts  of  coke  were  obtained ;  but  from  this  must  be  deducted  2-68  ashes,  and 
ri8  carbon  entering  into  combination  with  the  iron  ;  which  leaves  as  the  quantity  of  carbon 
actually  burnt  into  carbonic  oxide  before  the  tuyere  63-368 ;  part  of  this  carbonic  oxide 
undergoes  oxidation  into  carbonic  acid  at  the  expense  of  the  oxygen  in  the  oxide  of  iron 
which  it  reduces;  a  further  quantity  of  carbonic  acid  is  derived  from  the  limestone;  so 
that  the  gases  returned  to  the  mouth  of  the  furnace  by  the  combustion  of  the  07-228  parts 
of  coke,  the  reduction  of  the  corresponding  quantity  of  ore,  and  the  decomposition  of  lime- 
stone, consist  of — 

Nitrogen 282-860 

Carbonic  acid 59-482 

Carbonic  oxide 121-906 


404-248 
Add  to  this  the  products  of  the  distillation  of  the  coal,  and  we  get  the  following  as  the 
percentage  compositions  by  weight  and  measure  of  the  gases  issuing  from  the  mouth  of  the 
furnace. 

Nitrogen    - 

Carbonic  acid    .         -         -         -         - 

Carbonic  oxide 

Light  carburetted  hydrogen 
Hydrogen  -.---- 
Condensed  hydrocarbon     - 
Sulphuretted  hydrogen      -        -        - 
Ammonia 

100-000  100-000 


Bv  weight. 

By  volume 

59-559  - 

-      00-907 

12-705  - 

8-370 

26-000  - 

-      20-846 

1-397  - 

2-536 

0-078  - 

1-126 

0-108  - 

-        0112 

0-053  - 

0-045 

0-054  - 

-        0-058 

638  IRON. 

The  calculations  of  the  quantity  of  heat  capable  of  being  realized  in  the  furnace  by  the 
combustion  of  the  furnace  gases  are  founded  on  the  data  on  the  heat  of  combustion  given 
in  the  posthumous  papers  of  Dulong,  according  to  which — 

1  kilogramme  or  15,444  grains  of 

Carbon  burning  to  CO,  heats   15,444  grains  of  water  to  1499°C 

CO» 7371° 

Carbonic  oxide 2502° 

Hydrogen     -  34706° 

Light  carburetted  hydrogen 13469° 

defiant  gas  -         -         -     , 12322° 

Sulphuretted  hydrogen 447 tJ° 

Ammouia 6060° 

Using  these  numbers  it  is  found  that  by  the  combustion  of  100  of  the  furnace  gases 
there  are  generated  from  the 

5'J-55'J  nitrogen 0000 

12-705  carbonic  acid 0000 

26  Out;  carbonic  oxide C5067 

1-397  carburetted  hydrogen 18826 

0-078  hydrogen 2704 

0-108  olefiant  gas 1331 

0-053  sulphuretted  hydrogen 2G8 

0-034  ammonia 208 


88374  = 
units  of  heat  rtenerafcd,  the  nnit  being  understood  to  mean  the  amount  of  heat  necessary  to 
raise  1  kilogramme  =  2-204  lbs.  =  15,444  grains  of  water  from  0°  centigrade,  to  V  cent. 
The  amount  of  heat  realised  in  the  furnace  is  limited  to  that  produced  by  the  expenditure 
of  the  oxygen,  corresponding  to  59-559  nitrogen  in  the  production  of  carbonic  oxide  ;  this 
amounts  to  20,001  units :  hence  follows  the  rcniarkable  conclusion,  that  in  the  furnace 
which  was  the  subject  of  experiment,  not  less  than  81-54  per  cent,  of  the  fuel  is  lost  in  the 
form  of  combustible  matter  still  fit  for  use,  and  that  only  18-46  per  cent,  of  the  whole  fuel 
is  realized  in  carrying  out  the  processes  in  the  furnace. 

The  temperature  which  should  be  produced  by  the  flame  of  the  furnace  gases  when 
burnt  with  air,  is  found  by  dividing  the  units  of  heat,  viz.  883-74  arising  from  the  combus- 
tion of  1  kilogramme  of  the  gases  by  the  number  resulting  when  the  quantity  of  the  prod- 
ucts of  combustion  is  multiplied  by  their  specific  heat  (1-9338  x  0-2696) :  we  thus  get  the 
number  3083°  F.  ;  but  this  is  below  the  truth,  inasmuch  as  there  is  an  accession  of  combus- 
tible gases  at  the  mouth  of  the  furnace,  arising  from  the  decomposition  of  the  liquid  prod- 
ucts of  the  distillation  of  the  coal  in  its  passage  over  the  red-hot  fuel.  Making  proper  cor- 
rection for  this,  and  using  numbers  derived  from  actual  experiments,  Messrs.  Bunsen  and 
Playfair  calculated  the  tenjperature  of  the  gases  when  generated  imder  favorable  conditions 
at  3214°  F.,  and  even  this  may  be  increased  to  3632°  F.,  a  temperature  far  above  that  of 
cast  iron,  by  the  using  a  blast  sufficiently  heated.  In  utilizing  these  waste  gases,  care  must 
be  taken  not  to  remove  them  from  the  furnace  till  they  really  are  vaste,  that  is,  until  they 
have  done  their  work  in  the  furnace;  it  is  obvious  that  no  combustible  matter  could  be 
removed  from  the  lower  regions  of  the  furnace  without  seriously  deranging  the  operations 
essential  to  the  reduction  and  smelting  of  the  ore.  In  order  to  remove  the  gases  eftectually, 
and  without  injm-y  to  the  working  of  the  furnace,  and  in  such  a  state  as  will  permit  their 
coriil)Usfi()n  to  l)e  ed'ected  with  most  advantage,  the  height  of  the  furnace  must  be  raised, 
the  full  width  of  the  mouth  being  retained,  and  the  gases  nnist  be  withdrawn  sufficiently 
fiir  below  the  mouth  for  them  to  be  obtained  dry,  and  also  beneath  the  point  where  they 
begin  to  enter  into  combustion  from  contact  with  the  atmospheric  air. 

Various  modes  of  collecting  the  gases  have  been  tried  ;  the  best  seems  to  be  that 
adopted  at  Ebbw  Vale,  Sirhowy,  and  Cwm  Celyn.  A  funnel  shaped  casting,  equal  in  its 
largest  diameter,  to  the  throat  of  the  furnace,  projects  into  the  interior  a  depth  of  4  or  5 
fVct ;  the  orifice  at  the  liottom  from  3  to  5  feet  in  diameter  is  closed  by  a  conical  casting, 
the  apex  upwards,  from  which  a  cliain  proceeds  to  a  lever  liaving  a  counterpoise  at  the 
other  end.  (8ee /?>/.  338.)  The  materials  are  filled  into  the  funnel-shaped  receptacle,  and 
are  charged  into  tlie  furnace  with  a  uniform  distribution,  by  lowering  the  cone  by  means  of 
suitable  machinery,  which  again  returns  it  to  its  place  when  emptied.  The  circular  space 
around  the  funnel,  inside  the  furnace,  forms  a  chamber  for  the  reception  of  the  gases,  from 
wliich  they  are  conveyed  by  brick  tunnels  or  iron  piping  to  the  place  of  combustion.  The 
wliole  arrangement  will  be  clearly  understood  by  an  inspection  of  the  accompanying  plans, 
fif/x.  340,  341,  342,  343,  344,  kindly  furnished  to  the  writer  by  the  proprietor  of  the  Cwm 
Celyn  and  Blaina  Iron  Works. 


IRON. 


639 


Fig.  342  shows  the  plan  of  extracting  the  gases  which  is  adopted  at  the  Brymbo  Iron 
Works,  near  Wrexham,  the  same  being  the  patent  of  C.  E.  Darby. 


340 


^ 


341 


342 


It  consists  of  a  large  pipe  or  tube  inserted  into  the  middle  of  the  top  part  of  the  furnace, 
which  descends  a  short  distance  down  into  the  materials,  and  is  carried  over  the  top  of  the 
side  of  the  furnace  in  the  form  of  a  syphon,  a  continuation  of  which  pipe  is  taken  to  the 
boilers,  or  hot-air  stoves,  where  the  gas  is  burned  in  the  usual  way.  The  principal  advantage 
claimed  by  this  method  is  tliat  it  puts  no  check  on  the  free  escape  of  the  gases,  by  which 
the  driving  of  the  furnace  is  impeded,  and  the  quality  of  the  iron  deteriorated.  The  pat- 
entee estimates  the  saving  of  fuel  with  two  furnaces  making  240  tons  of  iron  per  week,  by 
applying  the  gas  to  the  blast  engine  boilers  and  hot-air  stoves,  at  £1,200  a  year.  Thus : — 
Consumption  of  fuel  at  engine  and  stoves  equal  to  7  cwts.  of  good  coal  per  ton  of  iron,  made 
at  3.V  per  cwt.,  is  2s.  OkZ .,  say  2.t.  per  ton  on  12,480  tons,  or  £1,248. 

The  causes  of  derangement  in  the  working  of  blast  furnaces  when  the  gases  are  drawn 
off  to  be  utilized  elsewhere,  have  been  diligently  studied  by  Mr.  George  Parry,  of  Ebhw 
Vale ;  and  he  has  kindly  furnished  us  with  the  following  resume  of  his  observations,  for 
insertion  in  this  article. 

The  manner  in  which  the  waste  gases  were  formerly  collected,  was  by  sinking  an  iron 
tube,  7  feet  deep,  into  the  throat  of  tlie  furnace,  the  diameter  of  the  tube  being  about  3 
feet  less  than  that  of  the  throat,  thus  leaving  an  annular  i^pnce  of  18  inches  between  the 
walls  of  the  furnace  and  the  sides  of  the  tube.  From  this  space  the  gases  were  allowed  to 
pass  off  by  the  pressure  within  tlie  furnace,  through  a  pipe  which  penetrated  the  ring  and 
walls.  When  the  tube  was  kept  full  of  minerals,  about  i  or  J  only  of  the  gas  escaped  into 
t!ie  open  air,  the  rest  passing  into  tlie  annular  chamber ;  and  when  this  state  of  things  was 
continued,  those  troublesome  adhesions  of  masses  of  semifused  materials,  above  and  around 
the  boshes,  technically  termed  "  .scaffolds,"  occurred,  with  the  usual  accompaniments  of 
l)lack  cinder  and  inferior  iron.  It  is  evident  that  when  the  tube  was  kef)t  full  of  minerals, 
the  contents  acted  as  a  loose  stopper  to  the  current  of  hot  gases  forced  up  by  pressure  from 
beneath,  and  diverted  them  towards  the  annular  space  where  there  was  no  such  resistance, 
thus  leaving  the  minerals  in  tlie  central  parts  of  the  furnace  in.suflicicntly  snp|)lied  with  the 
upward  current,  and  consequently  with  heat ;  the  minerals,  on  the  other  hand,  surrounding 
this  cold  central  cone,  were  supplied  with  more  than  their  usual  (luantity  of  boat,  as  w:is 
evidenced  by  the  burning  of  tuyJires,  and  by  the  destruction  of  the  brickwork  in  their 
neighborhood.    In  this  state  of  things  the  ores  in  the  external  portions  of  the  furnace  would 


640 


IRON. 


become  reduced  and  converted  into  gray  metal ;  while  those  in  the  central  portions  would, 
according  to  the  degree  of  deviation  of  the  ascending  current  of  heated  gases  from  them 
descend  to  the  point  of  fusion  either  thoroughly  deoxidized,  and  slightly  carbonized,  or 
possibly  with  a  portion  still  in  the  state  of  oxide,  and  mixing  there  with  the  properly  reduced 
ores,  enter  into  fusion  with  them,  producing  a  mixture  of  irons  which  must  necessarily 
prove  of  inferior  quality,  and  a  black  cinder  from  the  unreduced  oxides.  When  the  iron 
tube  in  the  throat  of  the  furnace  was  kept  only  partially  filled  with  minerals,  much  more 
gas  escaped  into  the  open  air,  as  might  have  been  expected,  and  consequently  more  trav- 
ersed the  central  parts  of  the  furnace  ;  and  it  was  always  observed  that  when  that  mode 
of  filling  was  adopted,  the  furnace  worked  much  better :  but  then  the  object,  viz.  that  of 

343 


economizing  the  gases,  was  not  attained.  Differently  formed  furnaces  were  found  to  be  dis- 
turbed in  different  degrees  by  this  system  of  drawing  off  the  gases  :  the  old  conical  narrow 
topped  furnaces  were  affected  very  much  less  than  the  improved  modern  domed  top  furnace 
of  large  capacity,  from  which  all  attempts  to  take  off  any  useful  portion  of  the  gases  proved 
absolute  ruin.  It  might  be  argued,  that  as  the  same  quantity  of  blast  and  fuel  was  used 
as  heretofore,  the  ascending  current  of  heated  gases  ought  to  produce  the  same  deoxidizing 
and  carbonizing  efFect  on  the  superincumbent  mass,  whatever  direction  they  might  take  in 
making  their  escape  at  the  upper  region  of  the  furnace  ;  for  if  the  central  part  should  not 
have  been  sufficiently  acted  upon,  the  external  annulus  would  have  more  than  its  usual 


IROiT. 


641 


share  of  chemical  influences.  But  when  it  is  considered  that  iron  is  only  capable  of  taking 
up  a  certain  quantity  of  carbon,  and  no  more,  it  follows  that  after  having  received  this 
dose,  its  further  exposure  in  the  external  parts  of  the  furnace  where  the  hated  gases  abound 

344 


can  do  nothing  towards  supplying  the  deficiency  of  carbon  in  the  metal  reduced  in  the  cen- 
tral part.  From  these  considerations,  it  became  evident  that  no  system  of  drawing  off  the 
gases  aroimd  the  sides,  whether  by  the  insertion  of  an  iron  tube  into  the  throat,  or  by  lat- 

345 


era!  openings  through  the  walls  into  a  chamber  surrounding  the  top  of  the  furnace,  can  be 
adopted  without  more  or  less  injury  to  its  action  ;  and  that  the  only  unobjectionable  mode 
Vol.  III.— 11 


642  IRON. 

would  be  to  take  the  gases  from  a  chamber  above  the  surface  of  the  minerals,  thus  equaliz- 
ing the  pressure  on  the  whole  sectional  area  of  the  mouth,  and  thereby  allowing  an  equally 
free  flow  for  the  ascending  current  up  the  middle,  as  well  as  up  the  sides  of  the  furnace. 
By  this  method  the  whole  of  the  waste  gases  would  become  utilized,  instead  of  a  portion  only 
and  the  fiuii'^ee  would  be  restored  to  its  original  state,  inasmuch  as  the  direction  of  the  flow 
of  heated  gases  would  not  be  interfered  with  by  unequal  resistance.  To  form  this  cham- 
ber, the  furnace  must  be  covered  in,  and  fed  through  a  hopper,  a  plan  long  adopted  at  the 
Codner  Park  Iron  Works,  with  the  supposed  advantage  of  scattering  the  minerals  around 
the  sides  of  the  furnace,  and  preventing  their  accunmlating  in  the  centre  ;  a  conical  charger 
of  this  description,  but  lixed  in  the  throat  of  the  blast  furnace,  was  in  use  at  the  Cyfartha 
Works,  more  than  half  a  century  ago,  the  minerals  being  thrown  by  baskets  to  the  centre 
of  the  cone,  and  allowed  to  roll  down  to  the  sides  of  the  fuinace,  thus  giving  a  cup  Ibim  to 
the  surface  of  the  minerals,  the  larger  lumps  of  course  rolling  to  the  centre,  and  afiording  a 
freer  passage  in  that  direction  for  the  upward  current.  It  was  not,  however,  until  January, 
1851,  that  a  trial  was  made  at  the  Ebbw  Vale  Works,  of  an  apparatus  of  this  description  lor 
collecting  the  gases.  It  was  then  supplied  to  one  of  the  old  forms  of  ('onical  furnace  with  a 
narrow  top,  and  the  trial  proved  eminently  successful,  the  furnace  producing  any  quantity  of 
iron  reijuired  according  to  the  burden,  as  usual.  Several  other  furnaces  were  similarly  fur- 
nished in  and  around  the  neighborhood,  and  it  was  now  thought  that  the  principle  of  taking 
oft'  the  gases  from  a  chamber  above  the  surface  of  the  mineraL\  together  with  the  conical 
mode  of  charging,  were  the  only  indispensable  conditions  to  success  for  all  furnaces ;  and 
some  even  which  were  originally  built  too  narrow  at  the  mouth,  were  actually  improved  by 
the  new  method  of  charging,  which  did  not  allow  of  the  surfaces  of  the  njincrals  rising 
higher  than  about  6  feet  I'rom  the  top  ;  thus  giving  to  the  furnace  a  diminished  height,  and 
as  a  consequence  of  its  conical  shape,  a  wider  mouth.  Further  experience,  however,  de- 
monstrated the  fallacy  of  this  general  conclusion. 

A  large  domed  furnace  was  furnished  with  the  same  kind  of  charging  apparatus  which 
l)roved  so  successful  in  former  instances,  but  to  the  astonishment  of  all  it  turned  out  a  com- 
plete failure,  the  same  derangements  occurring  as  in  the  former  cases,  where  a  portion  of 
the  gases  only  was  collected,  by  sinking  a  tube  into  the  throat.  Kow  this  furnace  could 
not  be  filled  to  within  6  or  7  feet  of  the  top,  and  at  that  depth  the  diameter  was  13  ft.  6  in., 
owing  to  the  sliarp  sweep  of  the  dome  ;  the  actual  working  furnace  was  therefore  37  feet 
high,  instead  of  44  feet,  with  a  mouth  13  ft.  6  in.,  instead  of  8  ft. ;  and  as  the  minerals  can- 
not lie  so  close  against  the  smooth  sides  of  the  walls  as  they  do  locked  in  each  other  in  the 
more  central  region  of  the  furnace,  a  much  freer  discharge  of  the  gases  up  the  sides  must 
take  place  ;  and  on  boring  a  hole  through  the  side  of  the  furnace,  in  the  neighborhood  of 
the  boshes,  it  was  found  that  2  feet  in,  the  coke  and  other  minerals  were  at  a  white  heat, 
but  a  little  further  on  towards  the  centre,  lumps  of  black  blazing  coal  were  found,  with 
ironstone  which  had  not  even  attained  a  red  heat.  The  charging  apparatus  was  now  raised 
with  the  furnace  5  feet,  and  the  minerals  drawn  up  an  inclined  plane  to  the  chargiiig  cup, 
thus  enabling  it  to  be  kept  full  to  within  a  short  distance  of  the  old  mouth,  after  which  the 
furnace  worked  a.s  usual.  That  diminished  height  was  not  the  cause  of  the  bad  working  of 
the  furnace  was  afterwards  proved,  the  furnace  having  been  blown  out  for  repairs,  and  re- 
lined  with  brickwork,  giving  it  that  form  and  proportion  deemed  necessary,  from  the  expe- 
rience gained ;  the  height  being  now  only  37  feet,  instead  of  44,  and  the  diameter  of  the 
mouth  7  ft.  6  in.,  or  one-half  of  that  at  the  boshes.  The  same  charging  apparatus  which 
failed  before,  mounted  G  feet  above  the  mouth,  was  used,  and  the  furnace  has  now  been 
working  uninterruptedly  for  5  years,  turning  out  as  much  as  160  tons  of  gray  pig  iron  per 
week,  or  when  burdened  for  white  iron,  '200  tons ;  economizing  the  whole  of  its  gas,  and 
as  much  under  the  control  of  the  manager  as  any  furnace,  either  closed  top  or  open  top, 
can  reasonably  be  expected  to  be.  It  is  clear,  therefore,  that  the  covering  of  the  top  has 
nothing  whatever  to  do  with  the  action  of  a  furnace  kept  full  to  the  mouth,  and  having  the 
proper  form  and  proportions  from  that  point  downwards.  The  month  must  be  understood 
to  be  that  part  of  the  furnace  which  represents  the  mean  height  of  the  surface  of  the  min- 
erals, and  not  the  top  of  the  masonry,  and  the  question  arises,  what  proportion  should  that 
bear  in  diameter  to  the  boshes  or  widest  part,  and  what  the  latter  should  be  with  reference 
to  height  in  order  to  secure  a  maximum  economical  effect  on  the  quality  of  the  iron  made, 
and  on  the  yield  of  fuel.  This  state  of  perfection  can  exist  only  when  the  isothermal  lines 
in  the  furnace  are  parallel  to  the  horizon  •,  tlie  temperature  of  the  minerals  at  any  given 
height  above  the  tuyeres  being  the  same  through  the  whole  horizontal  sectional  area  at  that 
height,  and  consequently  arriving  at  the  zone  effusion  in  an  equally  prepared  state.  If  the 
mouth  of  the  furnace  be  too  wide,  the  heated  gases  have  a  greater  tendency  to  pass  up  the 
sides  than  through  the  centre,  thus  destroying  the  liorizontality  of  the  lines  of  equal  temper- 
ature, and  giving  them  a  curved  form  with  the  convex  side  downwards  ;  hence  ores  of  differ- 
ent temperatures,  and  of  various  stages  of  preparation,  will  occupy  any  given  horizontal 
sectional  area  of  the  furnace  ;  these  descending  together,  and  mixing  in  the  zone  of  fusion, 
will  produce  evils  in  proportion  to  the  extent  of  the  deflection  of  the  curves  from  a  hori- 


IRON. 


643 


zontal  line.  On  the  contrary,  if  the  mouth  of  the  furnace  be  too  narrow  in  proportion  to 
the  other  parts,  we  may  expect  an  undue  portion  of  the  gases  to  pass  up  the  centre, 
leaving  the  minerals  around  the  sides  comparatively  unacted  upon.  It  is  easy  to  see  that 
evils  of  the  same  kind  as  before  must  exist  here,  the  isothermal  lines  becoming  now  concave 
downwards,  instead  of  convex,  giving  as  before,  through  any  horizontal  section  of  the  fur- 
nace, ores  at  various  temperatures,  and  at  different  degrees  of  deoxidation  or  carburation, 
according  to  the  depth  which  they  may  have  attained  in  the  furnace.  There  are  several 
instances  of  furnaces  originally  built  with  too  narrow  tops,  being  greatly  improved  by 
widening  them  ;  this  may  conveniently  be  done  by  feeding  them  through  a  conical  charger, 
which  by  lowering  the  surface  of  the  minerals  virtually  increases  the  width  of  the  mouth  : 
on  the  other  hand,  furnaces  having  the  opposite  defect  of  being  too  wide  at  the  top,  may  be 
benefited  to  some  extent,  provided  the  walls  are  nearly  perpendicular,  or  do  not  widen  too 
rapidly  downwards,  by  employing  as  large  a  cone  as  it  is  possible  to  work  in  the  throat ; 
for  by  the  use  of  this  feeder  the  minerals  must  fall  close  to  the  sides,  and  the  larger  lumps 
roll  to  thejixis  of  the  furnace,  and  so  facilitate  the  passage  of  the  gases  in  that  direction, 
besides  giving  to  the  surface  a  concave  or  cup  form,  and  consequently  a  diminished  height 
and  resistance  to  the  upward  current  in  the  middle.  This  principle  of  improving  the  charg- 
ing of  such  defective  furnaces  is  even  carried  out  to  some  extent  in  feeding  open  top  fur- 
naces where  the  gases  are  wasted.  The  charging  plate  is  so  placed  as  to  prevent  the  nose 
of  the  barrow  from  projecting  any  distance  into  the  furnace  ;  the  minerals  being  thus  dis- 
charged close  to  the  edge,  the  larger  lumps  have  a  tendency  to  roll  over  towards  the  centre, 
leaving  the  smaller  at  the  ring  walls,  to  check  the  upward  current  in  that  direction. 

The  above  considerations  will  materially  assist  in  furnishing  an  answer  to  the  oft  re- 
peated and  very  important  question,  "  What  form  and  proportion  should  a  blast  furnace 
have  to  produce  the  best  results  in  quality  of  iron,  and  in  economy  of  fuel,  whether  worked 
on  the  open  top  principle,  or  enclosed  for  the  purpose  of  utilizing  the  waste  gases  ?  "  Ex- 
perience has  proved  that  when  the  mouth  of  the  furnace  is  one-half  tlie  diameter  of  the 
widest  part,  good  work  is  obtained,  and  that  any  deviation  from  that  proportion,  if  in  excess, 
has  been  productive  of  great  derangement  in  its  action.  The  height  of  the  furnace  should 
also  bear  a  certain  proportion  to  the  greatest  diameter,  in  order  to  secure  a  uniform  flow 
of  tlie  ascending  current  through  all  its  parts  ;  for  if  the  widest  part  bear  too  great  a  rela- 
tion to  the  height,  the  boshes  nmst  necessarily  be  of  a  low  angle,  and  consequently  the 
minerals  around  the  sides  near  their  top  be  at  too  great  a  distance  out  of  the  direct  line  of 
passage  of  the  ascending  current,  and  consequently  remain  only  partially  prepared  for 
fusion. 

The  proportions  recommended  by  Mr.  Parry,  and  which  have  been  practically  tested 
most  satisfactorily  in  several  instances,  are  as  shown  infig.  346.  The  mouth  6'  b'  one-half 
the  diameter  of  the  widest  part  c  c,  and  this  should  not  be  at  a  less 
depth  than  its  own  diameter.  The  sides  of  the  furnace  to  this  depth 
should  be  formed  slightly  dome-fashioned,  for  the  purpose  of  giving 
to  that  region  a  larger  capacity  than  would  be  obtained  by  a  conical 
form.  The  radius  of  the  curve  should  be  at  right  angles  to  the  axis 
of  the  furnace,  and  formed  by  a  prolongation  of  the  line  represent- 
ing the  greatest  diameter.  When  tiie  radius  is  set  at  a  great  angle 
with  this  line,  which  is  often  done  to  give  greater  capacity  to  the 
domed  part,  the  distortion  produced  by  the  sharpness  of  the  curve 
may  leave  a  segment  of  the  minerals  unacted  upon  by  the  gases  in 
their  passage  to  the  mouth,  and  entail  greater  evils  than  would  be 
compensated  for  by  increased  capacity.  The  curve  is  continued 
below  the  widest  part  of  the  furnace  till  it  meets  the  top  of  the 
boshes  d  d,  the  angle  of  which  should  not  be  less  than  70°,  and  start 
from  the  point  of  the  tuyeres//.  The  depth  also  from  tlie  widest 
part  to  the  tuyeres  should  not  be  less  than  its  own  diameter  plus  half 
the  diameter  of  the  tuyeres.  These  proportions  give  a  blast  furnace, 
of  any  determinate  height  fixed  upon,  the  largest  possible  capacity 
it  is  capable  of  receiving,  while  remaining  free  from  any  distortion 
of  form,  likely  to  give  a  place  for  minerals  to  lie  out  of  the  way  of 
the  action  of  the  upward  gaseous  current ;  when  the  height  exceeds 
the  proportion  to  its  greatest  diameter  indicated  in  the  figure,  an 
unnecessary  sacrifice  in  its  capacity  is  the  only  loss  entailed.  The  height  above  the  mouth 
must  be  regulated  by  the  kind  of  hopper  used  for  cliarging,  where  it  is  intended  to  carry 
off  tlie  gases. 

Doubtless  when  the  true  principle  of  collecting  these  gases  without  injury  to  the  blast 
furnace  becomes  more  generally  known,  attention  will  be  directed  to  the  easiest  and  most 
convenient  mode  of  introducing  the  minerals.  Tlie  conical  charger  has  only  one  disadvan- 
tage, that  namely  of  allowing  a  great  waste  of  gas  during  the  charging ;  probably  some  kind 
of  revolving  hopper  may  be  contrived  to  remedy  this  defect.     It  is  of  course  assumed  that 


346 


644 


IRON. 


the  furnace  is  supplied  with  a  proper  quantity  of  blast,  and  of  a  density  proportionable  to 
the  diameter  across  the  tuyeres,  so  as  to  maintain  a  vigorous  combustion  of  the  fuel  to  tlje 
very  centre  of  the  hearth,  the  top  of  which  is  indicated  by  the  letters  e  e,  for  unless  this  is 
attained,  a  cold  cone  of  minerals  will  remain  in  the  centre,  and  produce  derangements 
wiiich  no  degree  of  perfection  in  the  form  of  the  furnace  in  the  higher  region  can  remove. 

Thevry  of  the  blast  furnace. — Analyses  of  the  gases  from  a  furnace  at  Alfreton  in  Der- 
byshire, at  various  depths  below  the  surface,  gave  to  Messrs.  Bunsen  and  I'layfair  the  re- 
sults embodied  in  the  subjoined  table.  The  furnace  was  supplied  with  80  charges  in  the 
course  of  24  hours,  each  charge  consisting  of  390  lbs.  of  coal,  420  lbs.  of  calcined  ironstone, 
and  170  lbs.  of  limestone,  the  product  being  140  lbs.  of  pig  iron.  The  gases  were  collected 
through  a  system  of  tubi's  of  malleable  iron,  1  inch  in  diameter,  and  were  received  in  glass 
tubes,  4  inches  long,  and  J  of  an  inch  in  diameter.  The  well-known  skill  of  M.  Bunsen  as 
a  gas  analy.st  is  a  guarantee  of  the  accuracy  of  the  determinations. 

Composition  of  the  Gases  taken  from  different  depths  in  the  Furnace. 


I. 

II. 

III. 

IV. 

V. 

VI. 

VII. 

VIII. 

IX. 

5  feet. 

8  fi-et. 

11  feet. 

14  feet. 

17  feet. 

20  feet. 

23  feet. 

24  feet. 

34  feet. 

Nitr(ij.'en 
Carlionic  aciil 
Carbimic  oxide 
Light  carbiiretted  1 
hyilriiL'en              ) 
TIv(iro2eii 
Olefianttras    - 
Cyanogen 

65-35 
7-77 
25-97 

8-75 

6-73 
0-4:i 

0-00 

54-77 
9-42 
20-24 

8-23 

6-49 
0-85 
0-00 

52-57 

9-41 

23-16 

4-57 

9-33 
0-95 
0-00 

5095 
910 
19-3 

6-64 

12-42 
1-57 
0-00 

55-49 
12-43 
lS-77 

4-81 

7-62 
1-3S 
0-00 

60-46 
10-83 
19-43 

4-40 
4-S3 
0  00 
0-00 

58-28 

8-19 

29-97 

1-64 

4-92 
0-00 
trace 

56-75 
10-08 
25-19 

2-33 

5-65 
0  00 
trace 

5805 

00- 

37-43 

0-00 

3-18 
0-00 
1-84 

From  these  analyses  it  appears  : — 

1.  That  at  a  depth  of  34  feet  from  the  top,  within  2  feet  9  inches  of  the  tuyere,  the  gas 
was  entirely  free  from  carbonic  acid,  but  contained  an  appreciable  quantity  of  cyanogen. 

2.  That  t!ie  nitrogen  is  at  a  minimum  at  14  feet. 

3.  That  carburetted  hydrogen  is  found  so  low  as  24  feet,  indicating  that,  at  that  depth, 
coal  must  be  undergoing  the  process  of  coking. 

4.  That  hydrogen  and  olefiant  gases  are  at  a  maximum  at  14  feet. 

5.  Tliat  the  proportions  between  the  carbonic  acid  and  carbonic  oxide  are  irregular, 
which  is  probably  to  be  explained  by  the  fact  that  water  is  decomposed  as  its  vapor  passes 
through  the  layers  of  hot  coal. 

The  average  composition  of  the  gases  evolved  from  the  materials  used  in  the  blast  fur- 
nace is  somewhere  between  the  two  following  numbers  :  — 

Nitrogen    -         -         -         - 
Carbonic  acid     -  -  - 

Carbonic  oxide 
Light  c;irburetted  hydrogen 
Hydrogen  ... 

Olefiant  gas 
Sulphuretted  hydrogen 
Ammonia  -         -         - 


60-907 

57-878 

S-STO 

9-823 

26-846 

24-042 

2-536 

2-743 

1-126 

4-972 

0-112 

0-392 

0-045 

0-035 

0-058 

0-115 

100-000 


100-000 


The  proportion  of  nitrogen  to  oxygen  as  an  average  deduced  from  these  analyses  is 
79-2  to  27.  The  product  of  the  combustion  of  coal  gives  the  same  proportions  as  those  ex- 
isting in  atmospheric  air.  Viz:  79.2  :  20.08.  The  excess  of  oxygen  must  therefore  depend 
upon  the  carbonic  acid  of  the  limestone,  and  the  oxygen  of  the  ore  given  to  carbon  during 
the  process  of  reduction.  Now,  as  at  a  depth  of  2-1  feet  the  gas  collected  contained  27-6 
and  26-5  oxygen  to  79-2  nitrogen,  it  is  held  that  at  this  depth  the  gas  must  already  have  ac- 
cumulated all  the  oxygen  of  the  ore,  and  the  carbonic  acid  of  the  limestone ;  and  the  con- 
clusion is  drawn  that,  in  hot  blast  furnaces  fed  with  coal,  the  reduction  of  the  iron  and  the 
expidsion  of  the  carbonic  acid  from  the  limestone  take  place  in  the  boshes  of  the  furnace. 
The  exact  region  of  the  furnace  in  which  the  melting  of  the  iron  and  the  formation  of  slag 
are  afTected  is  not  exactly  defined,  but  it  is  assmned  thiit  the  point  of  fusion  is  at  the  top  of 
the  hearth.  The  region  of  reduction  in  a  furnace  smelting  with  coal  must  be  much  lower 
than  when  the  fuel  is  coke  or  charcoal,  because  a  large  portion  of  the  body  of  the  furnace 
must  be  taken  up  in  the  process  of  coking,  and  the  temperature  is  thereby  so  depressed, 
that  it  is  sufficient  neither  for  the  reduction  of  the  ore,  nor  for  the  expulsion  of  carbonic 
acid  from  the  limestone. 

The  mean  general  results  obtained  by  M.  Ebelmen  from  a  charcoal  furnace  at  Clerval 
are  given  below.    The  methods  of  analysis  adopted  by  this  chemist  were  altogether  different 


IKON. 


645 


from  those  employed  by  Messrs.  Bunsen  and  Playfair. 
in  the  Annales  dex  J/««es,  vol.  six.  p.  89,  1851. 


For  details  we  refer  to  his  memoir 


No.  of  analysis  - 

L 

IL 

IIL 

IV. 

V. 

VI. 

VII. 

Depth  below  mouth - 

3  ft.  3  in. 

3  ft  3  in. 

9  ft.  9  in.  9  ft, -9  in. 

19  ft.  6  in. 

19  ft.  6  in. 

27  feet. 

Tymp. 

Carbonic  acid    .        .        - 
Carbonic  oxide  -        -        - 

1  Hydrogen  -        -        -        - 
Carburetted  hydrogen 

'  Nitrogen    -        .        -        - 

12-111 

24-60 

5-19 

0-93 

57 -^-^ 

11-95 

23-85 

4-31 

1-33 

5S-56 

4-14 
i  31-56 
i      3-04 

0-:i4 
1     60-92 

4-23 
81-84 
2-77 
0-77 
60-89 

0-49 

35-0O 

1-06 

0-36 

63  04 

0-07 

35-47 

1-09 

0-31 

63-06 

0-00 

87-65 

1-13 

0-10 

61-22 

Oi)3 

89 -se 

0-79 

0-^5 

58-17 

Totals 

loO.OO 
42-5 

100-00 

100-uO 

100-00 

100-00 

luO-00 

100-00 

100-00 

Oxygen,  per  100  nitrogen  - 

Carbon   vapor,   per  100 
nitrogen         ... 

40-3 

32-7 

32-7 

2S-5 

28-2 

30-7 

35-8 

32-8 

31-7 

29-6 

29-6 

2S-5 

28-5 

30-T 

35-9 

I.  Gas  taken  a  short  time  after  the  introduction  of  the  charge :  II.  the  same  taken  a 
quarter  of  an  hour  after  charging :  III.  gas  collected  through  a  ca.st-iron  tube  four  inches 
in  diameter ;  it  rushed  out  with  a  noise  and  gave  a  sheet  of  flame,  carrying  with  it  particles 
of  charcoal  and  dust :  IV.  gas  collected  by  boring  the  masonry ;  it  rushed  out  violently, 
burning  with  a  blue-colored  dame  :  V.  the  same  taken  an  hour  after :  VI.  gas  collected  by 
boring  the  masonry  at  the  back  of  the  furnace  about  3i  feet  above  the  tuyere;  it  burnt 
with  a  white  flame,  giving  olF  fumes  of  o-^iide  of  zinc ;  it  was  collected  through  porcelain 
tubes :  VII.  gas  collected  through  gun-barrels  lined  with  porcelain  ;  it  was  evolved  with 
sufficient  force  to  project  scoriae  and  even  cast  iron. 

The  furnace  was  working  with  cold  bla.«t  under  a  pressure  of  -44  inch  of  mercury.  The 
charges  had  the  following  composition  : — Charcoal,  253  lbs. ;  minerals,  (various,)  397  lbs. ; 
limestone,  254  lbs.  Thirty-two  charges  were  driven  in  twenty-four  hours  ;  the  furnace  was 
stopped  after  every  twenty  charges ;  the  produce  being  3,970  lbs.  of  black  cast  iron  ;  the 
daily  neld  being  about  6,175  lbs. 

Tiie  experiments  show  that  while  the  carbonic  acid  progressively  diminishes  downwards, 
the  carbonic  oxide  progressively  increases,  the  former  altogether  disappearing  at  a  depth  of 
27  feet.  On  examining  the  numbers  representing  the  oxygen  and  carbon  referred  to  100 
nitrogen,  it  is  seen  that  they  diminish  progressively  to  a  depth  of  19  feet,  the  oxygen  com- 
bined varying  from  42.5  to  28.2.  The  proportion  of  carbon  in  the  same  zone  rises  from 
28-5  to  32  8  ;  a  result  brought  about  as  much  by  the  carbonic  acid  disengaged  from  the 
minerals  as  from  the  gaseous  products  of  the  distillation  of  the  charcoal.  It  is  seen  that 
the  reduction  of  the  mineral  is  already  considerably  advanced  at  the  depth  of  19i  feet ;  and 
this,  so  to  speak,  without  any  consumption  of  charcoal,  but  through  the  conversion  of  car- 
bonic acid  into  carbonic  oxide.  The  hydrogen  decreases  as  the  carbonic  oxide  increases ; 
showing  that  this  gas  exercises  no  influence  in  the  reduction  of  the  ore. 

The  results  obtained  by  M.  Ebelmen  from  a  coke  furnace  at  Seraiug  were  as  under : — 


No.  of  experiment  -        -        - 

I. 

II. 

III. 

IV. 

V. 

VL 

Depth 

1  foot 

1  foot 

4  feet 

9  feet 

10  feet 

10  feet 

12  feet 

45  feet 

Carbonic  acid  -        -        -        - 
Carbonic  oxide        ... 
Hydrogen        .... 
Carburetted  hydrogen    - 
Nitrogen          .... 

11-39 

28-61 

2-71 

0-20 

5706 

11-39 
2S-93 
304 

58-64 

9-8.') 
28-06 
0-97 
1-48 
59-64 

1-54 

as  S3 

0-69 

1-43 

62-46 

1-08 
35-2 
1-72 

o-as 

61-67 

1-13 

35-35 

2 -OS 

0-29 

61-15 

0-10 

86-30 

201 

0'>5 

6134 

0-00 

45-05 

0-25 

007 

54-63 

Totals     .... 

100-00 

100-00 

100-00 

100-00 

100-00 

10000 

100-00 

liiO-OO 

Oxygen,  per  100  nitrogen 

45-0 

45-6 

40-0 

29  6 

30-2 

80-6 

29-9 

41-2 

Carbon  vapor,  per  100  nitrogen 

352 

35-7 

330 

29-4 

29-6 

30-0 

29^ 

41-3 

I.  Gas  obtained  by  plunging  an  iron  tube,  three  centimetres  in  diameter,  about  one  foot 
into  thfr  furnace :  II.  the  same;  the  gas  burnt  .spontaneously:  IV.  two  consecutive  anal- 
yses of  the  same  g.as :  V.  the  gas  was  collected  by  an  iron  tube :  VI.  gas  collected  by 
piercing  the  m;isonry  two  feet  above  the  tuyeres ;  the  gas  was  accompanied  by  fumes  of 
cyanide  of  p  )ta.<sium,  but  no  cyanogen  could  be  detached. 

The  furn:u-e  was  50  feet  high ;  tiie  air  was  supplied  through  two  tuyeres,  and  was  heated 
to  212"'  ;  it  was  firiven  at  the  rate  of  20,840  gallons  per  minute  under  a  pre.<.<ure  of  -5  of 
mercury.  The  charges  were  composed  of:  unroasted  minerals,  1,434  lbs.  ;  forge  cinders, 
1,434  lbs.  ;  limestone,  948  lbs.  ;  coke,  1,765  lbs.  The  metal  was  run  every  twelve  hours, 
and  17,500  lbs.  of  white  crystalline  cast  iron  obtained,  which  was  run  on  "thin  plates  and 


646  IRON. 

taken  directly  to  the  puddling  furnace.  The  yield  of  the  mineral  was  42  per  cent.,  and  the 
consumption  of  coke  1,500  per  1,000  of  cast  iron,  rising  from  1,800  to  2,000  per  1,000  of 
iron  when  the  furnace  was  working  for  foundry  iron. 

The  analyses  show  a  rapid  diminution  of  carbonic  acid,  and  indicate  that  in  the  upper 
regions  of  the  furnace  an  energetic  i-eduction  of  ores  takes  place  by  the  oxide  of  carbon 
under  the  influence  of  the  high  temperature  of  the  ascending  gases.  Between  one  and  nine 
feet  the  limestone  is  calcined.  Tlie  reduction  of  the  ore  takes  place  at  this  region  by  the 
conversion  of  carbonic  oxide  into  carbonic  acid,  without  change  of  volume,  and  without 
consumption  of  carbon.  The  increase  in  the  hydrogen  is  too  small  to  induce  a  supposition 
tliat  aqueous  vapor  in  decomposing  can  dissolve  any  notable  quantity  of  carbon.  The  gases 
collected  at  a  depth  of  about  12  feet  represent  about  the  mean  composition  of  the  gaseous 
mixture ;  from  that  point  to  a  depth  of  45  feet,  two-thirds  of  the  total  height  of  the  fur- 
nace, the  gases  do  not  sensibly  vary,  and  are  composed  almost  entirely  of  carbonic  oxide 
and  nitrogen.  At  12  feet  the  oxygen  is  to  the  nitrogen  as  29*9  to  100  ;  in  atmospheric  air 
it  is  as  26-3  to  100.  The  difference,  3-6,  represents  the  oxygen  arising  from  the  reduction 
of  the  silicates  of  iron  constituting  the  forge  cinders,  which  thus  is  seen  to  take  place  be- 
tween the  tuyere  and  a  depth  of  12  feet.  These  silicates  are  well  known  to  be  decomposed 
with  difficulty,  but  they  are  reduced  at  the  high  temperature  prevailing  in  that  zone  of  the 
furnace,  and  their  reduction  gives  rise  to  a  corresponding  quantity  of  carbonic  oxide,  to  a 
consumption  of  fuel,  and  to  a  considerable  absorption  of  latent  heat.  The  other  minerals 
are  reduced  higher  up  in  the  furnace,  and  this  is  common  to  all  coke  furnaces,  being  due  to 
the  high  temperature  of  the  ascending  gases,  a  temperature  much  higher  than  exists  in 
charcoal  furnaces,  a  far  larger  quantity  of  combustible  being  consumed.  Hence  it  is  that 
forge  cinders  can  be  successfully  used  in  coke  furnaces  ;  wliile  in  charcoal  furnaces  the  intro- 
duction of  small  quantities  only  alters  the  working  of  the  furnace,  makes  the  iron  white,  and 
corrodes  rapidly  the  walls  of  the  furnace  in  consequence  of  the  imperfect  reduction. 

From  his  eudiometric  experiments  on  the  gases  from  coke  and  charcoal  furnaces,  Ebel- 
men  deduces  the  following  conclusions  : — 

1.  That  the  amount  of  .carburetted  hydrogen  is  too  small  to  exercise  any  influence  over 
the  chemical  phenomena  of  the  furnace. 

2.  That  the  atmospheric  air  thrown  into  me  furnace  by  the  tuyere  produces  successively 
carbonic  acid  and  carbonic  oxide,  at  a  small  distance  from  the  opening.  The  first  of  these 
reactions  gives  rise  to  an  exceedingly  high  temperature ;  the  second,  on  the  contrary, 
causes  a  great  absorbtion  of  latent  heat,  and  a  corresponding  lowering  of  the  temperature 
of  the  gaseous  current.  The  limits  of  the  zone  of  fusion  bear  relation  to  the  space  in 
which  the  transformation  of  carbonic  acid  into  carbonic  oxide  takes  place. 

3.  That  the  ascending  current  consisting  of  carbonic  oxide  and  nitrogen,  with  a  little 
hydrogen,  produces  in  ascending  two  distinct  effvcts :  it  communicates  one  part  of  its  sen- 
sible heat  to  the  materials  of  the  descending  column  ;  it  becomes  charged  with  all  the  volatile 
products  disengaged  at  different  heights,  and  it  reduces  the  oxide  of  iron  to  the  metallic 
state.  Sometimes  this  transformation  gives  rise  to  an  increase  in  the  quantity  of  carbonic 
oxide  ;  sometimes,  on  the  contrary,  it  eff'ects  the  conversion  of  carbonic  oxide  into  carbonic 
acid  without  change  of  volume,  and  without  combustion  of  fuel.  Whenever  the  reduction 
of  oxide  of  iron  takes  place  with  the  production  of  carbonic  oxide,  there  is  a  consumption 
of  fuel,  and  an  absorption  of  latent  heat.  It  is  essential,  therefore,  to  the  good  working  of 
the  furnace  that  the  minerals  should  arrive  completely  reduced  to  that  part  v.here  the  tem- 
perature is  sufficiently  elevated  for  the  conversion  of  carbonic  acid  into  carbonic  oxide  by 
contact  with  carbon  ;  this  condition  is  nearly  always  realized  when  the  oxide  of  iron  is  in  a 
free  state  in  the  mineral.  The  reduction  of  the  oxide  when  in  combination  with  silica  re- 
quires, on  the  other  hand,  a  high  temperature,  and  it  can  only  take  place  in  that  zone  of 
the  furnace  where  the  carbonic  acid  has  completely  disappeared. 

4.  That  the  zone  where  carbonic  oxide  exists  alone  is  much  more  extended  in  coke  than 
in  charcoal  furnaces,  and  is  nearer  the  mouth  in  the  former  than  in  the  latter :  it  foils 
lower,  however,  in  the  cylinder  with  hot  blast,  the  quantity  of  heat  remaining  the  same. 

5.  That  the  volatile  gaseous  matters  from  the  distillation  of  the  charcoal  pass  into  the 
escape  gases,  and  exert  no  influence  on  the  reduction  of  the  minerals. 

The  mutual  relation  of  the  carbonic  acid  and  carbonic  oxide,  which  is  observable  in  the 
analyses  of  Ebelmen,  is  not  found  in  those  of  Bunsen  and  Playfair ;  this  is  attributed  by 
Ebelmen  to  the  circumstance  that  the  latter  chemists  collected  their  gases  through  narrow 
iron  tubes,  which,  becoming  intensely  heated  and  partially  choked  by  the  fragments  of  ore 
and  fuel  introduced  by  the  rapid  stream  of  gas,  so  modified  the  composition  of  the  gases, 
tliat  the  analysis,  however  carefully  conducted,  could  not  represent  accurately  their  real 
composition.  Ebelmen  collected  his  gases  through  wide  tubes,  and  from  the  lower  parts  of 
the  furnace,  by  piercing  the  solid  masonry.  It  is  obvious,  however,  that  none  but  very 
general  conclusions  can  be  drawn  from  the  analysis  of  the  furnace  gases,  in  whatever  way 
they  may  be  collected,  for  their  composition  cannot  be  the  same  under  all  circumstances ; 
the  nature  of  the  fuel,  the  pressure  of  the  blast,  and  (as  Mr.  Parry's  experiments  prove)  the 


IKON. 


647 


shape  of  the  furnace  itself,  must  each  exert  an  influence  in  modifying  the  circumstances 
which  affect  their  composition.  Although,  therefore,  it  is  impossible  to  fix  the  precise  re- 
gion of  the  furnace  where  the  reduction  of  the  oxide  of  iron  begins  to  take  place,  that  is, 
to  define  precisely  the  limits  of  the  ''  zone  of  reduction,"  we  may  in  considering  the  theory 
of  the  production  of  crude  iron  divide  the  furnace  into  four  zones  : — 1.  The  zone  of  reduc- 
tion ;  2.  The  zone  of  carburation  ;  3.  The  zone  of  fusion  ;  4.  The  zone  of  oxidation.  The 
zone  of  reduction  will  vary  in  extent,  according  as  the  furnace  is  working  with  coal  or  with 
coke  ;  with  hot  blast  or  with  cold.  The  zone  of  carburation  commences  just  below  the  top 
of  the  boshes,  the  reduced  metal  in  a  soft  and  malleable  state  here  acquires  carbon,  its  rapid 
sinking  being  retarded  by  the  contraction  which  the  sides  of  the  furnace  begin  to  undergo 
from  this  point  downwards.  As  the  carbonized  metal  passes  through  the  zone  of  fusion  it 
melts,  together  with  the  earthy  matters  which  serve  to  protect  it  from  the  oxidizing  effect 
of  the  fourth  zone,  that  of  oxidation,  t'.irough  which  it  passes  in  its  passage  through  the 
crucible.  If  the  temperature  of  the  zones  of  fusion  and  oxidation  be  not  much  higher  than 
the  malting  point  of  specular  iron,  the  metal  in  the  crucible  will  be  white,  with  little  or  no 
graphite ;  and  if  the  iron  remain  sufficiently  long  in  the  zone  of  carburation  to  take  up  the 
maximum  quantity  of  carbon,  it  will  be  bright  iron.  The  reduction  of  silicon  appears  to 
take  place  at  about  the  melting  temperature  of  specular  iron :  it  exists,  therefore,  in  small 
quantity  in  white  iron,  and  in  greatest  abundance  in  the  gray  iron  smelted  from  refractory 
ores,  wiiich  require  a  high  temperature. 

The  proportion  of  carbonic  acid  in  the  gases  obtained  from  different  heights  in  a  fur- 
nace, has  been  studied  by  MM.  E.  Montefiore  Levi  and  Dr.  Emil  Schmidt,  {Zeitschrift  des 
osten  Iiiffenieurverehies,  1S52.)  They  found  that  the  zone  from  which  this  gas  is  entirely  ab- 
sent is  of  very  limited  extent,  for  although  it  is  not  met  with  at  a  height  of  8  feet  from  the 
tuyere,  it  exists  at  9  feet  to  the  extent  of -i'TS  per  cent.,  above  which  point  it  diminishes  up 
to  15  feet,  where  it  is  0.  From  this  point  it  again  increases,  amounting  at  a  height  of  30 
feet  to  3o  per  cent.  It  then  gradually  diminishes,  until,  at  a  point  from  37  to  39  feet 
above  the  tuyere,  it  amounts  to  only  r69  or  TOl  per  cent. ;  after  which  it  goes  on  increas- 
ing with  rapidity  and  regularity  up  to  the  furnace  mouth.  The  carbonic  acid  existing  in  the 
furnace  gases  between  15  and  30  feet  is  referred  by  these  chemists  to  the  decomposition  of 
the  limestone  used  as  a  flux  ;  and  its'gradual  diminution  above  tliis  point  indicates  a  reac- 
tion of  considerable  importance,  that  namely  of  the  carbonic  acid  upon  the  ignited  coke 
carbon  being  taken  up  and  carbonic  oxide  formed.  Now,  the  quantity  of  carbon  taken  up 
by  275  parts  of  carbonic  acid  to  convert  it  into  carbonic  oxide,  amounts  to  75  parts,  and  as 
in  the  furnace  experimented  with,  20,000  kilogrammes  of  limestone,  containing  about  8,000 
kilogrammes  of  carbonic  acid,  were  consumed  every  2i  hours,  a  loss  of  fuel  equivalent  to 
2,173  kilogrammes  of  carbon  was  daily  occasioned  by  the  conversion  of  this  carbonic  acid 
into  carbonic  oxide,  and  this  may  be  considered  equivalent  to  2,500  kilogrammes  of  coke 
with  11  per  cent,  of  ash.  The  heat  absorbed  by  the  conversion  of  the  carbonic  acid  of  the 
limestone  into  a  gaseous  state  is  found  by  calculation,  taking  the  specific  heat  of  carbonic 
acid  at  022,  and  the  heating  power  of  coke  at  6,000,  to  be  equivalent  to  that  developed  by 
the  combustion  of  322  kilogrammes  of  coke.  Now  it  was  demonstrated  by  Dulong  that  the 
quantity  of  heat  disengaged  in  the  conversion  of  carbon  into  carbonic  oxide  is  much  less 
than  that  disengaged  in  the  conversion  of  carbonic  oxide  into  carbonic  acid,  although  the 
same  quantity  of  oxygen  is  required  in  both  cases.  The  conversion  of  carbonic  acid  into 
carbonic  oxide,  by  passing  over  ignited  carbon,  is  essentially  a  twofold  action ;  a  combina- 
tion of  carbon  with  oxygen,  and  a  decomposition  of  carbonic  acid  into  carbonic  oxide  and 
oxygen  :  the  former  is  accompanied  by  development,  the  latter  by  absorption  of  heat ;  the 
latter  preponderates  to  such  an  extent  as  to  indicate  a  loss  of  temperature  equivalent  to  the 
heat  developed  by  the  combustion  of  1,609  kilogrammes  of  coke. 

These  considerations  led  the  authors  to  employ  burnt  lime  in  working  blast  furnaces, 
and  thus  to  obviate  the  loss  of  heat :  the  results  were  not  at  first  satisfactory,  the  manage- 
ment of  the  furnace  being  very  difficult,  and  the  slags  black  and  pasty ;  but  subsequently 
the  working  was  regular  and  good,  and  the  saving  of  coke  and  the  increase  of  production 
are  stated  to  have  been  very  evident ;  moreover,  the  raw  iron  was  of  better  quality,  and  all 
the  interior  parts  of  the  furnace,  especially  the  tymp  stone,  remained  in  a  much  better  state 
of  preservation  than  when  limestone  was  used. 

Varieties  and  chemical  constitution  of  cast  iron. — In  commerce  there  are  four  principal 
varieties  of  cast  iron,  known  respectively  as  Xos.  1,  2,  3,  and  4,  or  dark  gray,  briqht  gra;j, 
mottled,  and  white  ;  these  terms,  although  convenient,  do  not,  however,  indicate  the  intrin- 
sic value  of  the  iron  thus  denominated,  as  the  variable  qualities  of  ore,  fuel,  and  limestone 
may  exercise  such  an  influence  on  the  resulting  crude  iron,  as  to  render  a  low  denomination 
of  one  manufacturer  of  greater  commercial  value  than  a  higher  denomination  of  other 
makers.  The  general  characters  of  the  four  varieties  are  these  : — No.  1.  Color,  dark  gray, 
in  large  rounded  grains,  obtained  commonly  near  the  commencement  of  the  casting,  when 
the  furnace  is  in  good  working  order,  and  when  an  excess  of  carbon  is  present ;  in  flowing 
it  appears  pasty,  and  throws  out  blue  scintillations.     It  exhibits  a  surface  where  crystalline 


648 


IKOif. 


Ye"'etations  develop  themselves  rapidly  in  very  fine  branches ;  it  congeals  or  fixes  very 
slowly ;  its  surface,  when  cold,  is  smooth,  concave,  and  often  charged  with  plumbago ;  it 
has  but  a  moderate  tenacity,  is  tender  under  the  file,  and  susceptible  of  a  dull  polish. 
When  melted  over  again,  it  passes  into  No.  2,  and  forms  the  best  castings.  No.  2,  color 
bright  gray,  of  small-grained  structure,  and  interspersed  only  with  small  graphite  laminaj ; 
possesses  great  tenacity,  is  easily  filed,  turned,  and  bored ;  may  even  be  hammered  to  a 
certain  extent ;  does  not  readily  crack  from  change  of  temperature.  No.  3  is  a  mixture 
of  white  and  gray  iron.  On  strongly  mottled  iron,  little  stars  and  spots  of  gray  iron  are 
found,  interspersed  in  bright  or  flowery  iron  ;  iveakly  mottled  iron  exhibits  white  specks  on 
a  gray  ground.  In  streaked  iron,  gray  iron  is  found  above  and  below,  and  bright  iron  in 
the  middle,  with  strong  demarcations.  No.  4.  White  iron  varies  from  tin  white  to  grayish 
white ;  it  is  very  brittle,  cracking  easily,  even  by  change  of  temperature ;  it  is  extremely 
hard,  sometimes  even  more  so  than  hardened  steel,  so  that  it  will  resist  the  strongest  file, 
and  scratches  glass  easily.  Fracture  sometimes  laminar,  sometimes  lamino-radiatin"  some- 
times finely  splintered,  sometimes  dense  and  conchoidal.  As  the  fracture  changes  from 
laminal  to  conchoidal,  the  color  likewise  varies  from  white  to  grayish.  Mean  specific 
gravity,  7 "5.  Expands  less  than  gray  cast  iron  when  heated,  cannot  be  welded,  because  it 
becomes  pasty  at  the  very  lowest  welding  heat.  When  heated  to  the  melting  point  it  does 
not  suddenly  pass  into  the  fused  state  like  gray  pig  iron,  but  is  converted  before  fusing  into 
a  soft  pasty  mass.  In  this  variety  of  pig  iron  the  whole  of  the  carbon  is  united  to  the 
iron ;  it  is  never  used  for  ca.sting,  but  always  for  conversion  into  malleable  iron.  The 
bright  iron  obtained  from  spathic  iron  ore  contains  the  largest  proportion  of  carbon,  (5"3 
per  cent,  according  to  Karsten.)  A  white  iron  is  always  the  result  of  a  derangement  in  the 
working  of  the  furnace,  though  it  by  no  means  follows  that  when  the  iron  is  white  the  fur- 
nace must  necessarily  be  in  a  disordered  state ;  the  presence  of  manganese,  for  example,  has 
a  tendency  to  make  white  cast  iron ;  but  the  quality  may  be  excellent.  The  white  iron  re- 
sulting from  derangement  flows  imperfectly,  and  darts  out  in  casting  abundance  of  white 
scintillations  ;  it  fixes  very  quickly,  and  on  cooling  exhibits  on  its  surface  irregular  asperi- 
ties, which  make  it  extremely  rough ;  it  is  exceedingly  hard,  though  it  is  easily  broken,  the 
fracture  being  radiated  and  lamellar ;  the  bar  iron  it  affords  is  of  inferior  description.  This 
kind  of  iron  is  always  produced  when  the  furnace  is  carrying  a  heavy  burden  of  forge  cin- 
ders containing  sulphur  and  phosphorus. 

Thus  there  are  two  distinct  kinds  of  white  cast  iron  : — 1st.  That  obtained  from  ores  con- 
taining a  large  proportion  of  manganese  crystallizing  in  large  plates ;  this  variety  is  highly 
prized  for  making  steel.  2d.  That  resulting  from  a  heavy  mineral  burden,  or  from  a  gen- 
eral derangement  of  the  furnace,  or  from  the  rapid  chilling  of  fused  gray  iron  crystallizing 
in  small  plates  ;  both  are  hard  and  brittle,  the  first  more  so  than  the  last.  Cast  iron,  which 
by  slow  cooling  is  gray,  becomes  white  when  it  is  cooled  rapidly ;  on  the  other  hand,  when 
white  iron  is  melted  and  allowed  to  cool  very  gradually,  a  portion  of  the  carbon  crystallizes 
out  as  graphite,  and  gray  cast  iron  is  produced. 


German - 
French  - 
American 
Silesian  - 
Scotch  - 
English  - 

"Welsh     - 


tion. 

( 

a. 

93-66 

\ 

b. 

9.3-29 

1 

c. 

91-42 

( 

d. 

95-18 

1 

e. 

93-39 

( 

f. 

94-87 

\ 

a- 

96-35 

\ 

h. 

96-55 

\ 

i. 

91-45 

1 

J- 

90-75 

( 

k. 

92-63 

\ 

I. 

92-06 

m. 

92-76 

\ 

n. 

89-45 

0. 

94-10 

P- 

95-27 

</• 

93-55 

r. 

91-92 

8. 

86-00 

t. 

91-29 

u. 

94  71 

0-48 
2-73 
1-44 

1-00 
•04 
1-14 
2-79 
4-94 
8-62 
1-40 


3-85 
1-99 
2-71 

8-40 
0-18 
8-07 
1-50 


1-20 


2-62 
2-50 
2-30 
1-S7  I  1-92 
2-42 
2 -SO 
4-00 
4-23 
4-17 
1-21 


Phos- 
phorus. 

Sulphur. 

Silicon. 

Manga- 

Total. 

1-22 

trace. 

0-79 

trace. 

100-00 

1-23 

'■ 

0-71 

" 

100-00 

1-22 

" 

8-21 

" 

100-00 

0-45 

0-03 

o-so 

" 

99-86 

0-38 

8-75 

1-30 

" 

100-00 

■22 

trace. 

1-80 

" 

100-00 

•21 

•01 

•79 

" 

100-00 

■17 

•06 

•82 

" 

99-89 

■12 

trace. 

•75 

8-38 

100-64 

326 

" 

■25 

2-00 

99  88 

r30 

140 

2 -SO 

. 

100-73 

0-46 

0-04 

8-83 

1-80 

1 00-81 

0-79 

0-04 

2-SS    • 

1-80 

100^77 

0-57 

0-02 

4-88 

222 

S9  44 

0-21 

trace. 

1-80 

M2 

100-62 

1  -(18 

0-S7 

0-36 

. 

100-00 

1-66 

0-14 

1-S5 

. 

100-00 

0-07 

0-01 

0-21 

8-05 

98-86 

0-06 

0-00 

0-62 

8-40 

99-31 

0-07 

0-01 

0-21 

411 

99-86 

1-84 

2-64 

010 

-     - 

100-00 

Sp.  Gr. 

7-48 
7-16 


7-159 

7-f4 

7-67 

7-53 

7-6 


a.  Very  gray  pig,  from  Lcerbach  in  the  Ilartz,  cold  blast:  h.  Mottled  iron,  from  the  royal  works  in 
the  Ilartz,  col(i  blast ;  c,  Normal  gray  pig,  from  the  .«ame  works,  hot  blast ;  d.  Gray  charcoal  pig,  cold 
blast ;  e.  White  pig,  from  Firmy,  very  short  and  brittle ;  f,  American  gray  pis,  charcoal ;  g,  American 
mottled  iron ;  /t,  American  cliarcoal,  white  iron ;  i,  Silesian  white  charcoal  iron,  very  crystalline  ;^?.  the 
same,  but  less  crystalline  ;  k.  Gray  Scotch  coke  pig.  from  the  Calder  iron  works ;  /,  Scotch  coke,  No.  3 
pig  iron;  in,  Glensarrick.  No.  3  pig;  «,  Coalbrookdale  Lightmoor  best  first  foundry  iron  ;  o.  Gray  pig 
iron  from  Dudley,  Stafford.shire;  ;;,  Ordinary  Aberdare  white  pig;  7.  Gr.iy  cinder  pig;  r,  White  crys- 
talline iron  pig,  smelted  from  manganiferous  ore;  «,  The  same;  ?,  The  same;  tt,  Ordinary  -white  pig. 


IRON.  649 

111  some  iron  works  six  varieties  of  pig  iron  are  recognized,  which  may  be  classified 
thus: — 1.  First  foundry  iron,  large  crystals  ;  2.  Second  foundry  iron,  large  and  small  crys- 
tals mixed  ;  3.  Dark  gray,  all  small  crystals ;  4.  Bright  gray  ;  5.  Mottled  ;  6.  White,  verg- 
ing on  mottled. 

The  preceding  table  exhibits  the  composition  of  some  different  varieties  of  Continental, 
English,  and  American  crude  irons.  The  methods  of  determining  the  various  elements  which 
nearly  always  accompany  cast  iron,  are  given  at  the  end  of  this  article. 

Besides  the  substances  enumerated  in  the  above  table,  other  metals,  such  as  copper, 
arsenic,  chromium,  titanium,  cobalt,  zinc,  tin,  aluminium,  and  the  metals  of  the  alkalies 
and  alkaline  earths,  are  occasionally  found  in  crude  iron,  but  very  rarely  in  quantities 
that  can  at  all  affect  the  qualities  of  the  product.  The  elements,  the  quantitative 
estimation  of  which  has  been  given  in  the  above  analyses,  do,  however,  materially 
modify  the  physical  qualities  of  cast  iron.  We  shall,  therefore,  offer  a  few  observations 
on  each. 

1st.  Carbon. — Iron  can  take  up  any  quantity  of  carbon  up  to  a  little  over  5  per  cent., 
at  which  point  it  becomes  saturated  ;  the  compound  thus  formed  is  the  white  crystalline  pig 
or  specular  iron  (i)  (r)  (s)  (t) ;  when  absolutely  pure  its  composition  is  94 '88  iron  and  5 '12 
carbon ;  it  is  a  tetra-carburet,  Fe^C.  The  most  highly  carburcttcd  iron  which  Faraday  and 
Sto  lart  could  produce,  consisted  of  iron  92'36,  carbon  5"64.  There  seems  no  reason  for 
admitting,  as  some  metallurgists  have  done,  the  existence  of  a  polycarburet  of  iron  con- 
taining 18'3  per  cent,  of  carbon,  inasmuch  as  iron  containing  under  6  per  cent,  appears 
to  be  completely  saturated.  The  specific  gravity  of  pure  tetra-carburet  of  iron  is  7 '66; 
it  is  the  most  fusible  of  all  the  carburets  of  iron,  its  melting  point  being  1,600°  Centi- 
grade ;  it  is  brittle  and  silver  white,  and  crystallizes  in  oblique  prisms,  which  are  fre- 
quently tabular.  According  to  Gurlt  the  carburet  of  iron  existing  in  gray  pig  is  the  ovto- 
cnrburet,  Fe"C,  the  crystals  of  which  belong  to  the  regular  or  cubic  system,  but  almost 
always  appear  in  gray  iron  in  the  form  of  confused  octohedral  groups.  The  specific 
gravity  of  pure  octo-carburet  of  iron,  according  to  the  same  authority,  is  Y'lS,  and  its 
composition  97"33  iron  and  2*63  carbon ;  its  color  is  iron  gray,  its  hardness  is  inferior, 
and  its  fusibility  less  than  that  of  specular  iron  ;  the  groups  of  crystals  often  found  in 
cavities  in  large  castings  are  composed  of  this  peculiar  carburet.  Gurlt  very  ingeniously 
endeavors  to  show  that  in  gray  pig-iron  the  carbon  of  the  octo-carburet  is  partially  replaced 
by  silicon,  sulphur,  and  phosphorus,  and  the  iron  by  manganese  and  other  metals.  In  like 
manner  the  carbon  of  the  tetra-carburet  may  be  partially  replaced  by  silicon,  phosphorus,  or 
sulphur,  the  eliminated  carbon  appearing  in  the  form  of  graphite  :  the  same  decomposition 
is  elFected  by  heat,  and  specular  iron,  if  exposed  to  a  temperature  considerably  above  its 
fusing  point,  becomes  (/ray ;  if  cooled  slowly,  the  graphite  separates  in  large  flakes,  if 
rapidly,  in  minute  particles.  Some  metallurgists  suppose  that  in  gray  cast  iron,  a  portion 
only  of  the  iron  is  chemically  united  with  carbon,  the  rest  of  'the  metal  being  dissolved  in 
the  carburetted  compound  in  the  form  of  malleable  iron  :  we  incline  however  to  the  opinion 
of  Gurlt,  that  the  whole  mass  of  the  iron  is  in  a  state  of  combination  with  the  electro- 
negative constituents,  such  as  carbon,  sulphur,  phosphorus,  and  silicon.  Thus  in  the  white 
pig-iron  of  heavy  burden,  {u,)  there  is  a  deficiency  of  carbon,  that  element  being  replaced  by 
sulphur  and  phosphorus. 

Karsten  gives  as  the  mean  of  several  analyses,  3'5865  per  cent,  as  the  quantity  of  carbon 
in  cast-iron  smelted  with  charcoal  from  spathic  ore.  He  states,  that  iron  containing  as 
little  as  2-3  per  cent,  of  carbon  still  retains  the  properties  of  cast-iron,  particularly  the 
faculty  of  separating  graphite  when  allowed  to  cool  slowly.  With  2  per  cent,  of  carbon 
iron  is  not  forgeable,  and  scarcely  so  if  it  contain  only  TO  per  cent.  With  this  quantity 
of  carbon  it  is  steel,  though  not  of  the  weldable  kind,  (cast  steel ;)  even  with  so  small  a 
proportion  of  carbon  as  \-^^  per  cent,  it  is  weldable  only  in  a  slight  degree;  the  latter 
property  increases  as  the  hardness  of  the  iron  decreases.  An  amount  of  from  1  "4  to  1  '5 
per  cent,  of  carbon  in  iron  denotes  the  maximum  of  both  hardness  .and  strength.  Iron  con- 
taining 0'5  per  cent,  of  carbon  is  a  very  soft  steel,  and  forms  the  boundary  between  the 
.steel  {i.  e.  iron  which  may  yet  be  hardened)  and  malleable  or  bar  iron.  These  limits 
lie  perceptibly  higher  if  the  iron  be  pure ;  and  lower  if  it  contain  silicon,  sulphur,  and 
phosphorus. 

The  composition  of  the  various  carbides  of  iron,  according  to  Berthier,  is  as  under : — 
FeC3.  FeC2.  FcC.  Fe^C.  Fe<C.  Fe«C. 

Iron  -  0-600  0-690  0-819  0899  0-947  0.9643 
Carbon  -  0-400  0-310  0-183  0-101  0.053  0-0367 
In  the  blast  furnace,  the  reduced  iron  may  take  up  caibon  in  two  different  ways : — 1.  By 
immediate  contact  with  the  incandescent  fuel ;  and  2.  By  taking  carbon  from  carbonic 
oxide ;  thus  Fe  -f  2C0  =  FeC  +  CO'^  That  iron  dccomi)oses  carbonic  oxide  is  considered 
by  Le  Piny  and  Laurent,  to  be  proved  by  the  following  experiment :  pure  oxide  of  iron 
and  charcoal  were  heated  in  two  sejxiratc  porcelain  boats,  placed  in  a. glass  tube;  the  air  in 
the  tube  furnished  oxygen  to  the  carbon ;  carbonic  oxide  was  formed,  which  was  converled 


650  IRON. 

iuto  carbonic  acid,  at  the  expense  of  the  oxygen  of  the  oxide  of  iron ;  the  carbonic  acid 
was  again  transformed  into  carbonic  oxide,  by  taking  up  a  fresh  quantity  of  carbon,  which  was 
again  converted  into  carbonic  acid  by  taking  oxygen  from  tlie  oxide  of  iron,  and  tliis  went  on 
until  the  whole  of  the  oxide  of  iron  was  reduced,  the  mctalHc  iron  then  decomposed  caibonie 
oxide,  producing  carbonic  acid  and  carbide  of  iron;  and  this  went  on  til!  a  certain  ([uantity 
of  carbon  had  combined  with  the  iron,  when  the  action  ceased.  If  the  charcoal  be  very 
strongly  ignited  previous  to  the  experiment,  the  carbonization  of  the  iron  docs  not  take 
place,  neither  does  pure  carbonic  oxide  carbonize  iron  when  passed  over  the  metal  at  a  red 
heat;  the  eflect  in  the  experiment  above  described  may  therefore  be  due  to  the  caiburetted 
hydrogen  evolved  from  the  charcoal.  Iron  begins  to  take  up  carbon  when  heated  only  to 
the  softening  point,  the  carbon  gradually  penetrates  the  metal,  converting  it  first  iiito  steel 
and  then  into  cast-iron  ;  conversely  melted  cast-iron  gives  up  carbon  to  soft  iron,  which  it 
converts  into  steel.  When  white  iron  (Fc'C)  is  heated  with  acids,  ncaily  the  whole  of  the 
carbon  is  eliminated  in  comliination  with  hydrogen.  Gray  iron  only  gives  up  to  hydrogen 
tlie  carbon  which  was  chemically  combined  with  the  iron,  the  uncombined  carbon  or  graphite 
remains  unacted  upon ;  the  dark  spot  produced  upon  gray  iron  by  a  drop  of  nitric  acid 
arises  from  this  separation  of  graphite. 

Phonplwrus. — In  very  few  specimens  of  crude  iron  is  this  element  wholly  absent ;  when 
it  exists  in  small  quantities  only,  it  is  said  rather  to  imi)rove  the  iron  for  castings,  as  it 
imparts  to  the  metal  the  property  of  fusing  tranquilly ;  in  a  larger  proportion  it  weakens 
the  iron.  In  like  manner  a  very  small  quantity  of  phosphorus  hardens  bar  iron  without 
materially  influencing  the  other  properties,  ))ut  when  it  exceeds  '5  per  cent,  it  renders  the 
bar  brittle,  cold  short,  as  it  is  termed.  According  to  Schatliaeutl,  both  cast-iron  and  steel 
are  imitroved  by  phosjihoinis  and  by  arsenic ;  he  found  the  latter  in  the  celebrated  Danne- 
niora  iron,  and  in  the  Lowmoor  iron,  and  the  former  in  the  equally  fixmous  Russian  (CCND) 
iron. 

Sulphur. — This  element  imparts  to  crude  iron  the  property  of  becoming  viscid,  and  of 
solidifying  quickly  with  cavities  and  air-bubbles.  It  is  not  certain  to  what  extent,  or  if  at 
all,  the  presence  of  minute  proportions  of  sulphur  reduces  either  the  tenacity  or  the  tough- 
ness of  cast-iron  of  given  quality  in  other  respects.  It  is  stated  in  the  Eeport  of  the  Com- 
mission of  Inquiry,  as  to  the  manufocture  of  ordnance  on  the  continent,  on  the  authority 
of  Schiir  and  Mitscherlich,  that  in  certain  Swedish  works  pyrites  is  thrown  into  the  furnace 
with  the  other  constituents  of  the  charge,  to  produce  the  fine  gray  mottled  iron  required 
for  gun  founding,  and  it  is  added  that  the  effect  may  be  analogous  to  that  of  the  oxidizing 
flame  in  a  reverberatory  furnace.  It  is  certain  that  sulphur  possesses  the  property  of  con- 
centrating carbon  in  iron :  and  as  mottled  iron  is  a  mixture  of  white  and  gray  iron,  it  is 
not  difficult  to  see  how  the  addition  of  pyrites  may  determine  the  formation  of  this  variety 
of  o;ist-iron  in  a  furnace,  which  without  it  would  produce  gray  iron  only ;  but  it  is  scarcely 
credible  that  any  intelligent  founder  would  resort  to  such  a  method  of  making  iron  for 
casting  cannon,  in  which  the  highest  possible  degree  of  tenacity  is  required.  The  fine  gray 
mottled  iron,  which  from  its  tenacity  is  known  to  be  best  fitted  for  large  castings,  is  said  to 
be  pi-epared  without  difSculty,  by  charging  the  furnace  partly  with  roasted  and  partly 
with  raw  ore,  and  so  regulating  the  blast  that  the  yield  shall  ije  regular,  and  the  slag 
nearly  colorless;  these  two  ores,  having  different  degrees  of  fusibility,  are  reduced 
after  different  periods  in  the  furnace,  and  hence  afford  one  of  them  gray,  and  the  other 
white  iron,  the  result  being,  provided  the  minerals  are  properly  proportioned,  a  mottled 
iron,  harder  and  more  tenacious  than  gray  iron,  obtained  by  mixing  or  by  smelting  in 
the  cupola.  It  is  desirable  that  the  temperature  of  the  furnace  sliould  be  kept  as  low 
as  possible,  the  production  of  dark  gray  graphitic  iron  resulting  always  from  intensity 
of  heat. 

When  sulphur  is  melted  with  iron  containing  the  largest  amount  of  chemically  combined 
carbon,  sulphuret  of  iron  is  formed  on  the  surface ;  underneath  a  layer  of  graphite,  and 
beneath  that,  a  layer  of  iron  with  the  maxhnum  of  carbon  :  and  when  (fra}i  iron  containing 
3"31  per  cent,  of  graphite  is  melted  with  sulphur,  white  iron,  containing  iron  9403,  com- 
bined carbon  4'93,  and  no  graphite,  is  formed.  The  tendency  of  sulphurous  ores  to  pro- 
duce white  metal  in  their  treatment  in  the  blast  furnace,  has  long  been  known  ;  it  was  sup- 
posed that  this  was  occasioned  by  the  too  great  fusibility  which  the  sulphur  gave  to  the  cast 
iron,  but  ores  containing  large  proportions  of  phosjjhoric  acid  will  produce  very  gray  iron, 
notwithstanding  their  fusibility^  so  that  this  explanation  does  not  serve  ;  the  experiments 
above  described  point  to  the  true  reason.  The  sulphur  present  in  the  ore  (if  as  sulphuric 
acid  reduced  in  the  furnace)  enters  into  combination  with  the  iron,  dis])lacing  a  correspond- 
ing proportion  of  carbon,  which  becomes  concentrated  in  the  remainder  of  the  metal, 
forming  white  iron.  To  guard  against  this,  and  in  order  to  obtain  a  metal  which  shall  con- 
tain a  minimum  amount  of  suljjhur,  the  slags  should  contain  i\ic  maximum  Vimo\\i\i  of  lime, 
M.  Berthier  having  shown  that  this  earth  decomposes  sulphuret  of  iron  at  a  high  tempera- 
ture, in  the  presence  of  carbon.  M.  Janoycr  states,  that  the  proportion  of  lime  and  silica 
in  the  slag  may  be  as  54  to  3G  ;  it  is  doubtful  whether  such  a  highly  basic  cinder  would  bo 


IRON. 


651 


sufficiently  fusible.  Direct  experiments,  however,  have  shown  that  the  amount  of  sulphur 
in  cast-iron  diminishes  in  proportion  as  the  amount  of  lime  in  the  slag  increases.  A  still 
better  flux  is  oxide  of  manganese,  and  it  is  found  that  when  the  manganiferous  spathose 
ore  constitutes  part  of  the  burden  of  the  furnace,  sulphur  almost  entirely  disappears  from 
the  crude  iron.  M.  Janoyer  believes  that  he  has  proved  experimentally,  that  the  whitening 
of  cast-iron  smelted  from  sulphurous  ores,  is  due,  in  part  at  least,  to  the  subtraction  of  u 
portion  of  its  carbon,  and  its  volatihzation  in  the  form  of  suljihuret  of  ciiibon,  by  which 
the  temperature  of  the  furnace  is  lowered ;  but  his  experiments  on  this  point  require  con- 
firmation. The  presence  of  a  very  small  quantity  of  sulphur  acts  very  injuriously  upon 
bar  iron,  so  small  a  proportion  as  Vioooo  rendering  the  metal  ''  hot  short,"'  that  is,  incapable 
of  being  worked  at  a  red  heat  under  the  hammer.  If  the  quantity  of  sulphur  in  the 
crude  iron  exceeds  0"4  per  cent.,  it  is  scarcely  po.ssible  to  manufacture  it  into  good  wrought 
iron. 

Silicon. — Like  carbon,  this  element  enters  into  combination  with  iron  in  all  proportions 
up  to  as  high  as  8  per  cent.  The  largest  quantity  found  by  Karsten  in  pig-iron  was  3 '46 
per  cent.,  but  in  the  above  table  a  specimen  («)  is  quoted  from  Coalbrook  Dale  containing 
■iSS  per  cent.  :  and  we  have  lately  found  it  in  a  sample  of  Nova  Scotia  iron  as  high  as 
5 "8  per  cent.  Generally  speaking,  gray  cast-iron  contains  more  silicon  than  white,  and 
the  greater  the  quantity  of  graphite  in  the  crude  iron  the  larger  the  amount  of  silicon, 
because  the  higher  the  temperature  of  the  furnace  ;  but  this  again  will  depend  materially 
on  the  quality  of  the  coal,  from  the  ash  of  which  the  silicon  is  probably  principally  derived. 
A  clean  strong  coal  yielding  a  small  percentage  of  ash  furnishes  a  cast-iron  with  less  silicon 
than  an  inferior  coal,  the  mineral  buiden  being  the  same.  Pig-iron  smelted  with  hot  blast 
contains  more  silicon  than  when  the  blast  is  cold,  because  of  the  higher  temperature  which 
prevails  in  the  fusion  zone  of  the  furnace.  Some  analyses  illustrating  this  fact  have  been 
already  given.  According  to  the  experiments  of  MM.  Janoyer  and  Gauthicr  the  amount 
of  silicon  in  hot  blast  cast-iron  may  be  greatly  influenced  by  varying  the  proportion  of 
limestone  in  the  furnace.  Pig-iron  obtained  with  a  charge  yielding  a  cinder  in  which  the 
lime  and  alumina  were  to  the  silica  as  V  is  to  10,  had  little  strength,  breaking  readily,  and 
analysis  showed  that  it  contained  3  per  cent,  of  silicon.  By  increasing  the  amount  of  lime 
in  the  charge,  so  as  to  obtain  a  cinder  in  which  the  bases  were  to  the  silica  as  8  is  to  10, 
and  at  the  same  time  employing  a  blast  of  the  highest  attainable  temperature,  the  iron  pro- 
duced had  a  much  greater  strength.  When  the  proportion  of  bases  to  silica  in  the  cinder 
was  as  20  is  to  19,  the  iron  contained  only  an  inappreciable  amount  of  silicon,  and  the 
strength  was  increased  in  the  proportion  of  65  to  45.  When  the  maximum  quantity  of 
lime  was  used  the  consumption  of  fuel  was  on  the  average  increased  to  the  extent  of  6 
per  cent. 

On  reading  the  above  account  of  the  experiments  of  Messrs.  Janoyer  and  Gauthicr,  the 
writer  of  this  article  induced  the  furnace  numager  of  the  Blaina  Iron  Works  to  increase 
the  yields  of  lime  on  one  of  his  furnaces  to  as  great  an  extent  as  in  his  judgment  it  would 
bear,  and  when  the  furnace  was  under  the  full  influence  of  the  excess  of  flux  to  forward 
him  samples  of  the  gray  pig  for  analysis.  The  following  results  show  that,  contrary  to  the 
statement  of  MM.  Janoyer  and  Gauthicr,  no  advantage,  as  regards  a  diminution  in  the 
amount  of  silicon,  was  hereby  obtained,  the  proportion  of  that  element  being  not  percepti- 
bly altered,  though  there  is  a  slight  diminution  observable  in  the  percentage  of  sulphur. 

Gray  pis:,  with  usunl  Gray  pis,  with  extra 

burden  of  liinc.  biirJen  of  lime. 

Sulphur 0-0G7     -         -         -         -     0-045 

Silicon 2-900     -         -         -         .     2-930 

As  the  presence  of  silicon  in  pig-iron  affects  in  a  remarkable  degree  the  yield  as  well  as 
the  strength  of  puddled  bars,  it  is  of  importance  that  this  element  .should  be  removed  as 
effectually  as  possible  by  a  refining  process  before  the  crude  iron  is  submitted  to  the  puddling 
process.  Pigs  with  3  per  cent,  of  silicon  give  about  G  per  cent,  of  silica,  and  this  requires 
somewhere  about  12  per  cent,  of  iron  to  form  a  cinder  sufficiently  fluid  to  allow  the  puddled 
iron  to  become  aggregated  into  balls ;  this  can  of  course  be  obtained  only  l)y  bxriiou/  that 
amount  of  iron  in  the  puddling  furnace  after  the  expulsion  of  the  carl)on,  and  while  the 
mass  is  in  a  powdery  state.  This  powdery  mass  is  composed  of  small  granules  of  iron 
mixed  up  with  a  gluey  infusible  cinder.  The  puddler  turns  over  this  mass  repeatedly  to 
expose  the  iron  to  the  oxidizing  influence  of  the  furnace ;  the  silica,  now  taking  up  suf- 
ficient oxide  of  iron  to  give  it  fluidity,  begins  to  separate  from  the  iron,  and  forms  a  pool  at 
the  bottom.  After  some  time  the  puddh'i-,  fimiiiig  tlie  mass  of  cinder  aceunndating  pretty 
fast,  makes  the  first  attempt  to  "  ball  up."  •  In  order  to  save  as  muth  iron  as  possible,  lie 
keeps  the  damper  down  and  works  tlie  powdery  mass  at  as  low  a  red  lu-at  as  po.'<sil>le.  The 
balls,  even  when  made,  will  not  bear  much  heat  under  the  hammer  without  falling  to  pieces, 
hence  an  imperfect  weld  in  the  hammered  mass  and  rolled  bar  is  tlie  result,  and  although 
the  iron  may  be  chemically  pure  it  is  deficient  in  strenr/lh.  By  protracting  tiie  process  and 
wasting  more  iron,  there  is  no  doubt  but  that  the  iron  nmjht  be  improved,  for  the  cinder 


652  IRON. 

would  become  richer  in  oxid^,  more  fluid,  and  consequently  offer  less  resistance  to  a  perfect 
weld.  Iron,  on  the  contrary,  with  a  small  percentage  of  silicon  may  be  "  balled  up" 
directly  it  is  "  dried,"  and  the  short  time  required,  for  that  operation  can  be  conducted  at 
the  highest  heat  of  the  furnace.  A  good  welding  of  the  mass  is  the  consequence :  such 
ii-on  is  atrong^  and  the  labor  of  the  puddler  in  obtaining  it  is  much  less  than  in  the  former 
cise.  Every  pound  of  silica  must  have  twice  its  weight  of  iron  to  form  a  cinder  sufficiently 
rich  in  oxide  to  allow  the  particles  of  iron  to  become  properly  agglutinated.  t>ueh  being 
the  influence  of  silicon  on  both  the  yield  and  the  strength  of  wrought  iron,  and  such  being 
the  waste  attendant  on  its  removal  in  the  refinery,  it  becomes  an  object  of  much  practical 
importance  to  prevent  as  far  as  possible  the  formation  of  a  silicide  of  iron  in  the  blast  fur- 
nace, and  the  observations  of  MM.  Janoyer  and  Gauthier  on  this  point  require  careful 
verification. 

Manganese. — The  presence  of  this  element  in  pig-iron  does  not  appear  to  exert  much 
influence  either  for  good  or  for  bad  on  the  quality  of  the  metal,  and  even  when  it  exists  in 
([uantity  amounting  to  4  or  5  per  cent,  in  the  crude  iron,  it  disappears  almost  entirely 
(luring  the  conversion  of  the  cast-iron  into  wrought  or  malleable.  It  has  already  been  ob- 
served that  the  cinder  from  iron  smelted  from  manganiferous  ores  contains,  generally 
speaking,  more  suli)hur  than  .'^lags  or  cinders  from  iron  ores  containing  no  manganese.  We 
have  had  numerous  opportunities  of  confirming  this,  and  have  therefore  on  this  account 
alone  attached  much  importance  to  the  existence  of  manganese  in  iron  ores ;  but  our  at- 
tention has  more  recently  been  directed  to  another  point  which  we  think  especially  worthy 
of  notice  of  iron  manufactures,  namely,  to  the  almost  jierfect  removal  of  pliosphorus  from 
pig-iron  containing  a  very  large  proportion  of  that  element,  and  at  the  same  time  a  high 
percentage  of  manganese.  As  our  experiments  on  this  important  point  are  still  in  prog- 
ress, we  shall  merely  here  quote  a  few  in  illustration  of  the  purifying  action  we  have 
alluded  to. 

Iron  made  from  a  highly  phosphorized  ore  containing  no  manganese : — 

Phosphorus 
per  cent. 
Pig 3030 

Puddled  bar 0-838 

Rough  down  bar       - 0.572 

The  finished  bar  was  cold  short  in  the  highest  degree  ;  it  was,  in  fact,  nearly  worthless. 
Iron  made  from  a  highly  phosphorized   ore   containing  a  large  percentage  of  man- 
ganese : — 

Phosphorus.  Manganese. 

Pig  -         -         -         -         -     2.00 7-20 

Puddled  bar     -        -        -    030 )  ^.„^ 

Do.  -         -         -    0-20 r^° 

Finished  bar  -  -  -  O'll 
The  iron  was  carefully  watched  during  the  puddling  process.  It  melted  very  thin,  and 
took  rather  more  work  than  usual ;  as  soon  as  the  boiling  commenced  it  was  very  violent, 
the  metal  forcing  itself  out  of  the  door  hole  until  it  was  checked.  When  it  "  came  to 
nature,"  as  the  workmen  term  it,  it  worked  beautifully  and  stood  any  amount  of  heat ;  in 
fact,  the  heat  could  with  difficulty  be  raised  to  the  retiuisite  degree.  The  yield  was  22  cwts. 
2  (|rs.  24  lbs.  of  pig  to  produce  1  ton  (of  20  cwts.)  of  puddled  bar ;  this  is  about  the  yield 
of  good  mine  iron  when  properly  puddled.  The  finished  bar  exhibited  none  of  the  cold 
short  quality,  it  was  exceedingly  ductile,  indeed  excellent  horseshoes  were  made  from  it. 
The  puddling  cinder  had  the  following  composition  : — 

Silica 8-240 

Protoxide  of  iron 70-480 

Oxide  of  manganese 12'800 

Phosphoric  acid 7-6CO 

Sulphur '535 

99-715 
Other  observations  have  shown  that  highly  manganiferous  pig  (without  phosphorus)  is 
puddled  with  difficulty,  and  sometimes  with  considerable  waste,  so  that  the  advantages  of 
an  alloy  of  manganese  would  seem  to  be  confined  to  thosie  varieties  of  crude  iron  into  the 
composition  of  which  phosphorus  largely  enters. 

JTie  Conversion  of  Crude  or  Carburized  Iron  into  Malleable  Iron. — This  is  effected  by 
one  or  more  operations,  which  are  necessarily  of  an  oxidizing  nature,  the  object  being  to 
eliminate  from  the  cast-iron  the  carbon  in  the  form  of  carbonic  oxide  gas,  and  the  silicon, 
sulphur,  phosphorus,  and  other  foreign  bodies  in  the  form  of  oxidized  products,  which 
pass  either  partially  or  wholly  into  the  scoria;  or  cinders.  The  pig-iron  is  either  subjected 
to  a  preliminary  dccarburation^  the  oxidizing  blast  hearth,  or  "  refinery,"  and  the  opera- 


IROK 


653 


tion  thus  commenced  afterwards  completed  in  the  oxidizing  air-furnace,  or  "  puddling  fur- 
nace ;  "  or  the  complete  conversion  of  the  crude  iron  is  effected  by  one  operation  in  the 
puddling  furnace,  by  the  process  called  "  boiling."  It  is  said  {Blackwdl)  that,  at  several 
works  abroad,  the  attempt  to  arrest  the  progress  of  decarburation  in  the  puddling  or  boil- 
ing furnace  at  that  point  in  which  the  conversion  has  proceeded  only  so  far  as  to  leave  the 
iron  in  the  state  of  steel,  or  subcarburet,  has  been  successful,  and  that  a  valuable  natural 
or  puddled  steel,  not  requiring  cementation  before  conversion  into  refined  or  cast  steel,  has 
been  the  result. 

English  Method  of  refining. — The  finery  furnace  is  composed  of  a  body  of  brick-work, 
about  9  feet  square,'  rising  but  little  above  the  surface  of  the  ground.  The  hearth,  the 
bottom  of  which  is  of  millstone  grit,  placed  in  the  middle,  is  2^  feet  deep  ;  it  is  rectangu- 
lar, being  in  general  3  feet  by  2,  with  its  greatest  side  parallel  to  the  face  of  the  tuyeres, 
and  it  is  made  of  cast-iron  in  four  plates.  On  the  side  of  the  tuyferes  there  is  a  single  brick 
wall,  on  the  three  sides  sheet-iron  doors  are  placed,  to  prevent  the  external  air  from  cooling 
the  metal,  which  is  almost  always  worked  under  an  open  shed  or  in  the  open  air,  but  never 
in  a  space  surrounded  by  walls.  The  chimney,  from  15  to  18  feet  high,  is  supported  upon 
four  columns  of  cast-iron  ;  its  lintel  is  4  feet  above  the  level  of  the  hearth,  in  order  that 
the  laborers  may  work  without  restraint.  The  air  is  supplied  by  the  blowing  cylinders 
which  supply  the  blast  furnace,  and  enter  the  hearth  through  6  tuyeres,  so  arranged  that 
the  current  issuing  from  those  on  the  opposite  sides  of  the  crucible  are  not  disposed  in  the 
same  plane.  These  tuyeres,  like  those  in  the  furnaces  in  which  cast-iron  is  made,  are  pro- 
vided with  double  casings,  through  which  a  current  of  cold  water  is  constantly  flowing,  and 
each  pipe  is  furnished  with  a  suitable  stop-valve  for  regulating  the  volume  of  the  blast. 
The  tuyeres  are  placed  at  the  height  of  the  lip  of  the  crucible  or  hearth,  and  are  inclined 
towards  the  bottom,  at  an  angle  of  from  25"  to  30°,  so  as  to  point  upon  the  bath  of  melted 
metal  as  it  flows.  The  quantity  of  air  blo\vn  into  the  fineries  is  considerable,  being  nearly 
400  cubic  feet  per  minute  for  each  finery.  The  ground  plan  of  a  finery  is  shown  in 
fig.  347,  A  being  the  hearth,  b  the  tapping  hole,  b  the  chill  mould,  and  a  a  a  a  a  a  the 
nozzles  of  the  tuyeres.  The  operation  of  refin- 
ing crude  iron  is  conducted  as  follows  :  A  fire  is 
lit  in  the  centre  of  the  hearth,  which  is  first  urged 
by  a  gentle  blast ;  a  charge  of  pig,  about  2  tons, 
is  then  laid  on,  and  the  whole  is  covered  up  dome- 
form  witha  heap  of  coke  ;  the  full  power  of  the 
blast  is  now  turned  on,  the  cast-iron  melts,  and 
flowing  down  gradually  collects  in  the  crucible, 
more  coke  being  added  as  the  first  quantity  burns 
away.  The  operation  proceeds  by  itself,  the 
melted  metal  is  not  stirred  about  as  in  some  modes 
of  refinery,  and  the  temperature  is  always  kept 
high  enough  to  preserve  the  metal  liquid.  Dur- 
ing this  stage  the  coals  are  observed  continually 
heaving  up,  a  movement  due'  in  part  to  the  action 
of  the  blast,  but  in  part  to  an  expansion  caused 
in  the  metal  by  the  discharge  of  carbonic  oxide 
gas.  When  all  the  pig-iron  is  collected  at  the 
bottom  of  the  hearth,  which  happens  in  about 
two  hours,  it  is  blown  vigorously  for  some  time 
►longer,  the  tap-hole  is  opened,  and  the  /?«e  metal 
runs  out  with  the  slag  into  the  chill  mould,  or  pit, 
as  it  is  called,  which  has  been  previously  wa.shed 
with  a  thin  clay  liquid,  to  prevent  the  refined 
metal  from  adhering  to  its  surface.  Tlie  chill 
mould  is  in  a  prolongation  of  the  tapping  hole  ;  it  is  a  heavy  cast-iron  trough,  about  10  feet 
long,  3  feet  broad,  and  2  to  2i  inches  deep.  The  slag,  from  its  inferior  specific  gravity, 
forms  a  crust  on  the  surface  of  the  metal :  its  separation  is  facilitated  by  tin-owing  cold 
water  in  large  quantities  on  the  fluid  mass  immediately  that  the  entire  ciiarge  has  left  the 
refinery.  This  sudden  chilling  of  the  metal  makes  it  exceedingly  brittle,  so  that  it  can  be 
broken  into  smaller  pieces  by  heavy  hammers,  for  the  subsequent  operation  of  puddling. 
The  rjfined  metal  is  very  white,  hard,  and  brittle,  and  possesses  in  general  a  fil)rous  radiated 
texture;  or  sometimes  a  cellular,  including  a  considerable  number  of  small  si>herical  cavities, 
like  a  decomposed  amygdaloid  rock.  The  loss  of  iron  in  the  refinery  process  is  very  large, 
varying  from  10  to  2i)  per  cent.  In  the  Welsli  iron  works,  1  ton  of  wjiite  iron  takes  from 
If  to  2  hours  to  refine,  the  consumption  of  coke  being  from  tj  to  S  cwts.,  and  the  loss  about 
3  cwts.  Gray  iron  takes  from  7  to  9  cwts.  of  coke  per  ton,  the  time  rctpiired  to  refine  being 
from  2^  to  3  hours,  and  the  loss  of  iron  ])er  ton  4  cwt.  The  pig-iron  to  be  decarburized  in  the 
refinery  is  freiiuently  mixed  with  rich  silicates,  (forge  cinders,)  and  occasionally  with  oxides  of 


654  IRON. 

iron,  the  object  being  to  protect  the  melted  metal  in  some  degree  from  the  oxidizing  effects  of 
the  blast,  and  to  react  on  the  carbon  which  it  contains.  The  quantity  einployed  depends  on  the 
degree  to  which  the  pig-iron  is  carburized.  The  crude  iron  from  which  wrought  iron  of  the  bc*t 
quality  is  produced,  is  that  possessing  a  medium  degree  of  carburation,  or  what  is  generally 
termed  gray  pig-iron.  White  iron,  which  possesses  an  inferior  degree  of  fluidity  to  gray  pig- 
iron,  and  which  comes  as  it  is  termed  more  rapidly  to  nature,  is  that  quality  which  is  most 
generally  em[)loyed  in  the  manufacture  of  wrought  iron,  especially  when  the  conversion  is 
effected  in  the  single  operation  of  boiling  in  the  puddling  furnace  ;  but  this  species  of  pig- 
irou  being  the  result  of  imperfect  reactions  in  smelting,  is  always  more  impure  than  gray 
iron  obtained  from  the  same  materials,  and  docs  not  produce  wrought  ii  on  of  the  best  quality. 

The  colce  employed  in  the  refinery  should  be  as  free  as  possible  from  shale,  and  should 
contain  only  a  low  percentage  of  ash  ;  it  should  especially  be  free  from  sulphuret  of 
iron,  which  it  often  contains  in  considerable  cpiantity,  as  it  is  found  that  nearly  the 
whole  of  this  sulphuret  enters  into  combination  with  the  metal,  and  docs  not  pass  off  in 
the  slags. 

Refineries  arc  sometimes  worked  on  hot  fluid  iron,  run  direct  from  the  hearth  of  the 
blast  furnace,  a  considerable  saving,  both  of  time  and  fuel,  being  hereby  cfi'ected.  Various 
proposals  have  been  patented  for  the  employment  of  fluxes  to  assist  in  the  removal  of  the 
impurities  of  cast-iron,  both  in  the  refining  and  puddling  furnaces.  Thus  Jlr.  Hampton 
patented,  in  185.5,  a  flux,  prepared  by  slaking  quicklime  with  the  solution  of  an  alkali,  or 
alkaline  salt.  •  MM.  Du  Motay  and  Fontaine  propose,  in  a  patent  secured  in  1856,  to  purify 
and  decarbonize  iron  in  the  refining  and  puddling  furnace,  by  the  employment  of  fluxes 
prepared  from  the  scoria;  of  the  puddling  furnace,  from  oxides  of  iron  and  silicates  or 
carbonates  of  alkalies,  or  other  bases.  Mr.  Pope  (1856)  proposes  to  add  the  residue  ob- 
tained by  the  distillation  of  Boghead  or  Torbane  mineral,  to  such  fuel  as  is  eniploycd  in 
the  refining  of  iron.  Mr.  Sanderson,  of  Sheffield,  (1855,)  employed  for  the  refining  of  iron 
such  substances  as  sulphate  of  iron,  capaUe  of  disengaging  oxygen  or  other  elements, 
which  will  act  upon  the  silicium,  aluminium,  kc,  contained  in  the  metal.  These  and 
various  other  .schemes  have  been  suggested  with  the  object  of  lessening  the  enormous 
waste  which  pig-iron  undergoes  on  its  pas.«age  through  the  refinery  ;  for  as  the  process  is 
at  present  conducted,  the  partial  elimination  of  the  carbon,  sulphur,  phosphorus,  kc,  is 
only  effected  at  the  expense  of  a  large  quantity  of  iron,  which  is  oxidized  by  the  blast,  and 
passes  in  the  form  of  silicate  into  the  slag;  the  desideratum  is  the  discovery  of  some 
method  of  reducing  the  oxide  of  iron,  and  substiiutiiig  for  it  some  other  base,which  will 
form  with  silica  a  sufficiently  fusible  silicate.  Mi-,  lilackwell  suggests  that  the  decarbura- 
tiou  of  pig-iron  might  be  effected  by  remelting  it  in  a  cupola  furnace,  either  alone,  or  with 
minerals  containing  nearly  pure  oxides  of  iron  ;  the  oxide  of  iron  would  be  reduced  by 
the  carbon  of  the  pig-iron,  while  the  silicates  of  the  fuel,  with  the  silica,  alumina,  and 
other  easily  oxidizable  alloys  eliminated  from  the  cuide  iron,  would  be  sepaiated  in  the 
form  of  fusible  earthy  glass.  The  employment  of  stc;im  as  a  purifying  agent  for  crude 
iron  has  been  patented  by  several  persons.  Mr.  Xasmyth  in  1854  obtained  a  patent  for  the 
treatment  of  iron  in  the  puddling  furnace  with  a  current  of  steam,  which  being  introduced 
into  the  lower  part  of  the  iron,  passes  upwards,  and  meeting  with  the  highly  heated  metal 
undergoes  decomposition,  both  elements  acting  as  purifying  agents.  The  steam  employed 
is  at  a  pressure  of  about  5  pounds  per  square  inch,  and  pas.ses  into  the  metal  through  a 
species  of  hollow  rabble,  the  workman  moving  this  about  in  the  fused  metal  until  the  mass 
begins  to  thicken,  which  occurs  in  from  five  to  eight  minutes  after  the  introduction  of  the 
steam ;  the  steam  pipe  is  then  removed  and  the  puddling  finished  as  usual. 

The  advantages  are  said  to  consist  in  the  time  saved  at  each  heat  or  puddling  operation,* 
(from  ten  to  fifteen  minutes;)  the  very  effective  purification  of  the  metal;  and  the  possi- 
bility of  treating  iiighly  carbonized  pig-iron  at  once  in  the  puddling  furnace,  the  preliminary 
refining  being  thus  avoided.  In  October,  1855,  Mr.  Bessemer  patented  a  somewhat  simi- 
lar process  for  the  conversion  of  iron  into  steel,  the  steam  highly  heated,  or  a  mixture  of 
air  and  steam,  being  forced  through  the  liquid  iron  nui  from  the  furnace  into  skittle  jxits. 
Steam  being  u.sed  only  at  an  early  stage  of  tlip  process,  and  the  treatment  finished  with 
heated  air.  In  the  early  part  of  the  same  year  Jlr.  Martien,  of  New  Jersey,  obtained  a 
natent  for  a  partial  ])urification  of  crude  iron,  by  causing  air  or  steam  to  pass  up  thrcuigh 
the  liquid  metal,  as  it  flows  along  gutters  from  the  top  hole  of  the  furnace  or  finery  forge ; 
and  he  subsequently  proposed  to  include  with  the  air  or  steam,  other  purifying  agents, 
such  as  chlorine,  hydrogen,  and  coal  gas,  oxides  of  manganese,  and  zinc,  &c.  Other 
methods  of  treating  crude  iron  with  air  and  steam  were  made  the  subjects  of  patents  by 
Mr.  Be.asemer  in  December  1855  and  January  1856.  In  October  a  patent  for  the  en.ploy- 
ment  of  steam  in  admixture  with  cold  blast  in  the  smelting  furnace  and  fining  forge,  was 
obtained  by  Messi-s.  Armitage  and  Lee,  of  Leeds,  and  in  August  a  patent  was  obtained  by 
Mr.  George  Parry,  of  the  Ebbw  Vale  Iron  Works,  for  the  purification  of  iron  by  means  of 
highly  heated  steam.  The  fluid  iron  is  allowed  to  run  into  a  reverberatory  furnace  pre- 
viously heated,  and  the  steam  is  made  to  impinge  upon  it  from  several  tuyeres,  or  to  pass 


IRON.  655 

through  the  metal.  Steel  is  to  be  obtained  by  treating  highly  caiburetted  iron  with  the 
steam,  and  then  running  it  into  water,  and  fuzing  it  with  the  addition  of  purifying  agents, 
or  adding  to  it  in  the  furnace  a  small  quantity  of  clay,  and  afterwards  about  10  or  15  per 
cent,  of  calcined  spathose  ore.  Mr.  Parry  observing  that  when  steam  was  sent  through 
the  molten  iron,  as  in  Mr.  Nasmyth's  proces-?,  the  iron  quickly  solidilied,  conceived  the  idea 
of  communicating  a  high  degree  of  heat  to  the  steam  by  raising  the  steam  pipe  a  couple 
of  inches  a'>ove  the  surfice  of  the  metal,  so  that  it  might  be  exposed  to  the  intensely 
heated  atmosphere  of  the  furnace  ;  and  also  of  inclining  the  jet  at  an  angle  of  45',  so  a.s 
to  give  the  molten  mass  a  motion  round  the  furnace  while  the  pipe  was  maintained  in  the 
sa;ue  position  at  a  little  distance  beyond  the  centre :  when  this  was  done,  in  a  fev.-  minutes 
the  iron  began  to  boil  violently,  the  rotatory  motion  of  the  fluid  bringing  every  pai  t  of  it 
successively  into  contact  with  the  highly  heated  mixture  of  steam  and  atmospheric  air,  and 
soliditication  taking  place.  Having  thus  ascertained  the  proper  way  of  using  steam  as  a 
refining  agent,  it  Ov'curred  to  Mr.  Parry  that,  as  the  presence  of  silicon  in  tl;e  pigs  for 
puddling  aftects  in  a  remarkable  degree  the  yield  of  iron,  as  well  as  its  strength,  it  is  a 
matter  of  consequence  that  this  element  should  be  removed  as  completely  as  possible  pre- 
vious to  the  puddling  operation  ;  the  steaming  of  the  iron  would  probably  therefore  be 
more  protltably  applied  in  the  refinery  than  in  the  puddling  furnace.  Pig-iron  containing 
3  per  cent,  of  silicon  gives  6  per  cent,  of  silica,  which,  to  form  a  cinder  sufficiently  fluid  to 
allow  the  balling  up  of  the  iron,  would  require  from  10  to  12  per  cent,  of  iron  ;  and  this 
can,  of  course,  only  be  obtained  by  burning  that  amount  of  iron  in  the  puddling  furnace, 
after  the  expulsion  of  the  carbon,  and  while  the  mass  is  in  a  powdery  state.  The  super- 
heated steam  is  injected  on  the  surface  of  the  iron  in  the  refinery  i*.  water  tuyeres, 
similar  to  those  used  for  hot  blast  at  smelting  furnaces ;  they  are  inclined  at  an  angle  of 
about  45"  ;  some  are  inserted  at  each  side  of  the  door  of  the  furnace,  and  are  pointed  .so 
a3  to  cross  each  other,  and  give  the  iron  a  circulating  motion  in  the  furnace.  The  tuyeres 
are  from  f  to  +  an  inch  in  diameter ;  a  little  oxide  of  iron  or  silicate  in  a  state  of  fusion 
on  the  surface  of  the  iron  accelerates  the  action,  as  in  common  refineries,  and  increases 
the  yield  of  metal,  but  to  a  much  greater  extent  than  when  blasts  of  air  are  used.  The 
steam  having  been  turned  on,  the  mass  of  iron  commences  circulating  around  the  inclined 
tuyeres,  and  soon  begins  to  boil,  and  the  action  is  kept  uniform  by  regxdating  the  flow  of 
the  steam.  The  most  impure  oxides  of  iron  may  be  used  in  this  process,  such  as  tap  cinder 
or  hammer  slag  from  puddling  furnaces,  without  injury  to  the  quality  of  the  refined  mctnl 
made  ;  the  large  quantities  of  sulphur  and  phosphorus  which  they  contain  being  eflectually 
removed  by  the  detergent  action  of  the  heated  steam.  When  4  cwt.  of  cinders  are  used 
to  the  ton  of  pig,  20  cwt.  of  metal  may  be  drawn,  the  impurities  in  the  pig  being  replaced 
by  refined  iron  from  the  cinders. 

We  have  had  several  opportunities  of  witnessing  this  beautiful  refining  process  at  the 
Ebbw  Vale  Iron  Works,  and  have  made  the  following  analysis  of  the  cinders  and  metal, 
which  fully  bears  out  the  above  statements : — 

Graphite  .  .  -  . 
Silicon  .... 

Slag 

Sulphur  .... 
Phosphorus  -  -  -  - 
Manganese  -         -         -         - 


Sulphur       .... 
Phosphoric  acid  - 

A  ton  of  gray  iron  may  be  refined  by  steam  in  half  an  hour,  using  seven  jets  of  steam 
•|  of  an  inch  in  diameter,  and  with  a  pressure  of  from  30  to  40  lbs.  ;  the  temperature  of 
the  steam  being  from  Gt'O'  to  700^  F.,  the  orifices  of  the  tuyeies  being  2  or  3  inches 
above  the  surface  of  the  iron.  As  the  fluidity  of  the  metal  dei)ends  upon  the  heat  which 
it  is  receiving  from  the  combustion  of  the  fuel  in' the  grate,  and  not  on  any  generated  in 
it  by  the  action  of  the  steam,  it  is  evident  that  the  supi>ly  of  the  latter  in  a  given  time 
must  not  exceed  a  certain  limit,  or  the  temperature  of  the  fluid  iron  will  become  reduced 
below  that  of  the  furnace.  This,  however,  partly  regulates  itself,  and  does  not  require 
much  nicety  in  the  management,  for,  if  too  much  steam  be  given,  the  ebullition  becomes 
so  violent  as  to  cause  the  cinders  to  flow  over  the  bridges,  giving  notice  to  the  refiner  to 
slack  his  blast.  The  "  forge  cinders  "  used  in  the  steam  refinery  contain  6t')  per  cent,  of 
iron;  the  "run  out"  cinder  contains  only  26;  40  per  cent,  of  iron,  or  thereabouis,  have 
therefore  been  converted  into  refined  metal,  and  the  resulting  cinder  is  as  pure  as  the 
ordinary  Welsh  mine,  witii  its  yield  of  25  per  cent  of  iron.  The  following  is  the  result 
of  one  week's  work  of  the  steam  refiuerv  : — 


Pig  iron. 

Eefincd  metal. 

-     2-40 

. 

- 

0-30 

-     2-68 

. 

- 

0-32 

-     0-68 

. 

. 

0-00 

-     0-22 

. 

. 

0-18 

-     0-13 

. 

. 

0-09 

-     0-86 

- 

- 

0-24 

Forjre  cindor.<;  thrown 

Cinder  rnn  out  of 

into  tlie  r^-linerv. 

tlic 

refinery. 

-      1  -34 

- 

- 

0-16 

-     2-0(J 

- 

- 

0-129 

656 


IRON. 


Pigs  used 
Metal  made 

Loss 


cwt.  qrs,  lbs. 

396  0  15 

393  3  1 

2  1  14 


350 


o; 


349 


Yield 20       0       14 

The  quantity  of  cinder  (puddling)  used  was  3^  cwt.  per  ton  of  pig.  When  l^  cwt.  of 
cinders  were  used  to  1  ton  of  pig,  the  yield  was  invariably  20  cwt.  over  a  malie  of  about 
\00  tons. 

lu'Jiuinff  b>/  (jaf,  {German  method.) — The  most  simple  form  of  gas  reverberatory  furnace 
is  that  known  as  Ecii's  furnace,  which  is  employed  at  the  government  works  of  Gloi- 
witz  and  Konigsliiitte,  for  refining  iron  made  on  the  spot.  Tlie  i'ollowing  description  and 
plan  of  this  furnace  is  extracted  from  a  report  to  the  secretary  of  state  for  war,  from  tlie 
superintendent  of  royal  gun  factories,  Colonel  Wilmot,  R.  A.,  and  the  chemist  of  the 
War  Department,  Profes.>;or  Abel. 

The  gas  generator  (which  replaces  the  fireplace  of  the  ordinary  reverberatory  furnace) 
i.s  an  oblong  chamber,  the  width  of  which  is  3  feet  9  inches,  and  the  height 
348  from  the  sole  to  the  commencement  of  the  sloping  bridge  6  feet  4  inclies. 
It  tapers  slightly  towards  the  top,  so  as  to  Jacihtate  the  descent  of  the 
fuel,  which  is  introduced  through  a  lateral  opening  near  the  top  of  the 
geucr;itor.     Its  cubical  contents  are  about  44  feet. 

The  air  necessary  for  the  production  of  the  gas  is  supplied  by  a  feeble 
blast,  and  enters  the  generator  from  the  two  openings  or  tuyeres  of  a  long 
air  chest  of  iron  phite  {Jigs.  348,  349,  35u)  fixed  at  the  back  of  the  cham- 
ber, near  the  bottom.  The  space  between  the  air  chest  and  the  sole  of 
the  chambers  serves  as  a  receptable  for  the  slag  and  ash  from  the  fuel. 
There  are  openings  on  the  other  side  of  the  chamber,  opposite  the  tuy- 
eres, which  are  generally  closed  by  iron  plugs,  but  are  required  when  the 
ijl  ife==t:  :  tuyeres  have  to  be  cleaned  out.  There  is  an  opening  below  the  air-chest, 
'  '  '     through  which  fire  is  introduced  into  the  chamber,  when  the  furnace  is  set 

to  work,  and  wliich  is  then  bricked  up,  until  at  the  expiration  of  about  14 
days  it  becomes  necessary  to  let  the  fire  die  out,  when  the  slag  and  ash 
which  have  accumulated  on  the  sole  of  the  chamber  are  removed  through 
this  opening. 

The  hearth  of  the  furnace  is  constructed  of  a  somewhat  loamy  sand ; 
its  general  thickness  is  about  6  inches ;  its  form  is  that  of  a  shallow  dish, 
with  a  slight  incline  towards  tlie  tap  hole;  the  iron  is  prevented  from  pen- 
etrating through  the  hearth  by  the  rapid  circulation  of  cold  air  below  the  fire-bridge  and 
the  plate  of  the  hearth. 

Figs.  351  and  352  represent  the  upper  oblong  air-chest  pro- 
vided with  a  series  of  tu}6res,  whicli  enter  the  top  of  the  furnace 
just  over  the  fire-bridge  at  an  angle  of  30".  The  air  forced  into 
the  furnace  through  these  tuyeres  serves  to  inflame  and  burn  the 
gases  rushing  out  of  the  generator,  and  the  direction  of  the  blast 
throws  the  resulting  flame  down  upon  the  metal  on  the  hearth, 
in  front  of  the  bridge.  This  air-chest  communicates,  like  the 
other  one,  by  pipes,  with  the  air  accumulator  of  the  neighboring 
blast  furnace.  The  amount  of  pressure  employed  is  about  4  lbs. ; 
but  the  supply  of  air,  both  to  the  generator  and  the  inflammable 
gases,  admits  of  accurate  regulation  by  means  of  valves  in  the 
eoimecting  pipes.  There  is  an  opening  in  the  arch  at  both  sides 
of  the  furnace,  not  far  from  the  bridge,  into  which,  at  a  certain 
stage  of  the  operations  tuyeres  are  introduced,  (being  placed  at 
an  angle  of  25,°)  :dso  connected  with  the  blast  apparatus  and 
provided  with  regulating  valves. 
The  refining  process  is  conducted  as  follows  : — The  hearth  of  the  furnace  having  been 
constructed  or  repaired,  a  brisk  coal  fire  is  kindled  in  the  generator,  through  tlie  opening 
at  the  bottom,  which  is  afterwards  bricked  up.  About  2o  cubic  feet  of  coals  are  then 
introduced  from  above,  and  the  necessary  supply  of  air  admitted  to  the  generator  through 
the  lower  air-chest.  When  these  coals  have  been  thoroughly  ignited,  the  generator  is 
filled  with  coals,  and  a  very  moderate  supply  of  air  admitted  tlirough  the  tuyeres  below, 
(for  the  generation  of  the  gas,)  and  those  over  tlie  bridge,  (lor  its  combustion.)  until  the 
furnace  is  dried,  when  the  supply  of  air  at  both  places  is  increased,  so  as  to  raise  the 
hearth  to  the  temperature  necessary  for  baking  it  thoroughly,  upon  which,  about  40  cwt. 
of  iron  are  introduced,  the  metal  being  distributed  over  the  whole  hearth  as  uniformly 
as  possible,  and  the  size  of  the  pieces  being  selected  with  the  view  to  expose  as  much  sur- 


351 


u 


352 


& 


IROIf. 


657 


face  as  possible  to  the  flame.  The  fusion  of  the  charge  of  metal  is  effected  in  about  three 
hours,  the  coal  used  amounting  to  about  3f  cubic  feet  per  hour.  The  gas  generator  is 
always  kept  filled  with  coal,  and  the  supply  of  air  admitted  from  below  is  diminished  by 
a  regulation  of  the  valve,  whenever  fresh  coal  is  supplied,  as  the  latter,  at  first,  always 


Eck's  Gas  Eeverberatoiy  Furnace.— Front  view. 


.•^^•''-- 


LoDgitudinal  Section. 


yields  gas  more  freely.  The  arrangement  of  the  upper  row  of  tuyferes  effects  the  com- 
bustion of  gases  just  as  they  pass  from  the  generator  on  to  the  hearth.  The  hottest 
portion  of  the  furnace  is  of  course  near  the  fire-bridge,  i.  c,  where  the  blast  first  meets 
with  the  gases.  During  the  melting  process  the  iron  is  shifted  occasionally,  so  that  the 
Vol.  III.— 12 


658 


IROX. 


cooler  portion  near  the  flue  may  in  its  turn  become  melted  without  loss  of  time.  When 
the  iron  is  ascertained  to  be  thoroughly  fused,  about  6  lbs.  of  crusted  Hniostone  are 
thrown  over  its  surface  for  the  purpose  of  converting  the  dross  which  has  separated  into 


Cross  section  at  c,  d,  on  Plan. 

fusible  slag.  The  two  side  tuyeres  are  now  introduced  into  the  furnaces  through  the 
openings  above  alluded  to,  the  width  of  the  nozzle  employed  depending  upon  the  power 
of  the  blast  used.     The  air  rushing  from  these  tuytires  impinges  with  violence  upon  the 


IKON".  659 

iron,  and,  the  two  currents  meeting,  an  eddying  motion  is  imparted  to  the  fused  metal. 
In  a  short  time  the  motion  produced  in  the  mass  is  considerable ;  the  supernatant  slag  is 
blown  aside  by  the  blast,  and  the  surface  of  the  iron  thus  exposed  undergoes  refinement, 
while  it  changes  continually,  the  temperature  of  the  whole  miss  being  raised  to  a  full 
white  heat,  by  the  action  of  the  air.  The  iron  is  stirred  occasionally,  in  order  to  insure 
a  proper  change  in  the  metal  exposed  to  the  action  of  the  blast.  A  shovelful  of  lime- 
stone is  occasionally  thrown  in,  (the  total  quantity  used  being  about  1  per  cent,  of  the 
crude  iron  employed.)  The  slag  produced  is  exceedingly  fusible,  and  is  allowed  to  re- 
main in  the  furnace  until  the  metal  is  tappud,  and  on  cooling  it  separates  from  it  completely. 

The  duration  of  the  treatment  in  this  furnace  after  the  metal  is  fused,  varies  from  two 
hours  and  a  half  to  five  hours,  according  to  the  product  to  be  obtained.  For  the  prep- 
aration of  perfectly  white  iron,  the  treatment  is  carried  on  for  five  hours.  A  sample  is 
tapped  to  examine  its  appearance,  when  it  is  believed  to  be  sufficiently  treated. 

When  the  charge  is  to  be  withdrawn  from  the  furnace,  the  side  tuyere  nearest  the  tap 
hole  is  withdrawn,  so  that  the  blast  from  the  opposite  tuyere  may  force  ihe  metal  towards 
the  hole.  Tlie  fluid  iron,  as  it  flows  from  the  taphule,  is  fully  white  hot,  and  perfectly 
limpid  ;  it  chills,  however,  very  rapidly,  and  soon  solidifies.  A  few  pails  of  water  are 
thrown  upon  those  portions  of  the  metal  which  arc  not  covered  with  the  slag,  which 
flows  out  of  the  furnace,  the  object  being  to  cool  it  rapidly,  and  thus  prevent  the  oxida- 
tion of  any  quantity  of  iron.  Tlie  loss  of  metal  during  the  treatment  is  said  not  to  ex- 
ceed 5  per  cent. 

With  regard  to  the  purification  which  the  iron  undergoes  in  the  gas  reverberatory 
furnace,  it  appears  to  be  confined  chiefly  to  the  elimination  of  carbon  and  silicium,  the 
amount  of  sulphur  and  phosphorus  undergoing  but  little  alteration,  as  appears  from  the 
following  analysis  {Abel) : — 

Pig  iron.  Eeflned  iron. 

Silicium     ...         -  4-66         -         -         -         0-62 

Phosphorus        -         -         -  0.56         -         -         -         0-50 

Sulphur     -         -         -         -  0-04         -         -         -         0-03 

Nevertheless  the  iron  thus  refined  is  highly  esteemed  for  all  castings  which  are  required 
tg  possess  unusual  powers  of  resistance :  some  experiments  made  to  ascertain  the  com- 
parative strain  borne  by  the  refined  metal,  and  the  same  metal  as  obtained  from  the 
blast  furnace,  showed  the  strength  of  the  former  to  be  greater  by  one  half  than  that  of 
the  latter. 

T/ie  operation  of  puddling. — In  the  years  1783  and  1784,  Mr.  Ilenry  Cort  of  Gosport 
obtained  two  patents,  one  for  the  puddling,  and  the  other  for  the  rolling  of  iron,  "dis 
coveries,"  says  Mr.  Scrivenor,  "  of  so  much  importance  in  the  manufiicture,  that  it  must 
be  considered  the  era  from  which  we  may  date  the  present  extensive  and  flourishing 
state  of  the  iron  trade  of  this  country." 

The  object  of  Mr.  Cort's  processes  was  to  convert  into  malleable  iron,  cast  or  pig  iron, 
by  means  of  the  flame  of  pit-coal  in  a  common  air  furnace,  and  to  form  the  result  into  bar 
by  the  use  of  rollers  in  the  place  of  hammers.  The  process  was  managed  in  the  follow- 
ing manner: — "The  pigs  of  cast  iron  produced  by  the  smelting  furuace  are  broken  into 
pieces,  and  are  mixed  in  such  proportions  according  to  their  degree  of  carbonization,  that 
the  result  of  the  whole  shall  be  a  gray  metal.  The  mixture  is  then  speedily  run  into  a 
blast  furnace,  where  it  remains  a  suflicicnt  titne  to  allow  the  greater  part  of  the  scoriie 
to  rise  to  the  surfiice.  The  furnace  is  now  tapped,  and  the  metal  runs  into  moulds  of 
sand,  by  which  it  is  formed  into  pigs,  about  half  the  size  of  those  which  are  broken  into 
pieces.  A  common  reverberatory  furnace  heated  by  coal  is  now  charged  with  about  2^ 
cwt.  of  this  half-refined  gray  iron.  In  a  little  more  than  half  an  hour,  the  metal  will  be 
found  to  be  nearly  melted;  at  this  period  the  flame  is  turned  off",  a  little  water  is  sprin- 
kled over  it,  and  a  workman,  by  introducing  an  iron  bar  through  a  hole  in  the  side  of  the 
furnace,  begins  to  stir  the  half-fluid  mass,  and  divide  it  into  small  pieces.  In  the  course 
of  about  50  minutes  from  the  commencement  of  the  process,  the  ii'on  will  have  been  re- 
duced by  constant  stirring  to  the  consistence  of  small  gravel,  and  will  be  considerably 
cooled.  The  flame  is  then  turned  on  again,  the  workmen  continuing  to  stir  the  metal, 
and  in  three  minutes'  time  the  whole  mass  becomes  soft  and  semifluid,  upon  wiiich  the 
flame  is  then  turned  off.  The  hottest  part  of  the  iron  now  begins  to  heave  and  swell, 
and  emit  a  deep  lambent  blue  flame,  which  appearance  is  called  fernientalion  ;  the  heav- 
ing motion  and  accom[)aiiying  flame  soon  spread  over  the  whole,  and  the  heat  of  the 
metal  seems  to  be  rather  increased  than  diminished  for  the  next  quarter  of  an  hour  ;  after 
this  period  the  temperature  again  falls,  the  blue  flame  is  less  vigorous,  and  in  a  little 
more  than  a  quarter  of  an  hour  the  metal  is  cooled  to  a  dull  red,  and  the  jets  of  flame 
are  rare  and  faint.  Din-ing  the  whole  of  the  fermentation  the  .<?tirring  is  continued,  by 
which  tlie  iron  is  at  length  brought  to  the  consistency  of  sand;  it  also  approaches  ni'arer 
to  the  malleable  state,  and  in  consecjuence  adheres  less  than  at  first  to  the  tool  with 
which  it  is  stirred.     During  the  next  half  hour  the  flame  is  turned  off  and  on  seveial 


660  IRON. 

tiiiios,  a  stronger  fermentation  takes  place,  the  lambent  flame  also  becomes  of  a  clearer 
;iiiil  lighter  blue;  the  metal  begins  to  clot,  and  becomes  much  less  fusible  and  more  tena- 
cious than  at  first.  The  fermentation  then  by  degrees  subsides ;  the  emission  of  blue 
flame  nearly  ceases;  the'  iron  is  gathered  into  lumps  and  beaten  with  a  heavy-headed 
tool.  Finally,  the  tools  are  withdrawn,  tlie  apertures  through  which  they  were  worked  are 
closed,  and  the  flame  is  again  turned  on  in  full  force  for  si.x  or  eight  minutes.  The 
pieces,  being  thus  brought  to  a  high  welding  heat,  are  withdrawn  and  shingled;  after  this 
they  are  again  heated  and  passed  through  grooved  rollers,  by  which  the  scoritE  are  sep- 
arated, and  tiie  bars  thus  forcibly  compressed  acquire  a  high  degree  of  tenacity."  But 
tliis  mode  of  refilling  did  not  produce  altogether  the  desired  result.  It  was  irregular  ; 
sometimes  the  loss  of  iron  was  small,  but  at  others  it  was  very  considerable,  and  there 
were  great  variations  in  the  quality  of  the  iron,  as  well  as  in  the  quantity  of  fuel  consum- 
ed. These  diflicidties  were,  however,  removed  by  the  introduction  of  the  coke  finery  by 
the  late  Mr.  Samuel  Homlray,  of  Penydarran,  upon  which  the  puddling  and  balling  fur- 
naces came  immediately  into  general  use,  with  the  addition  of  rollers  in  lieu  of  hamnieis. 

Mr.  I'on's  first  patent,  which  is  for  "  rolling,"  is  dated  17th  January,  1783  ;  his  second, 
that  for  "  pmldling,"  is  dated  13th  February,  1784.  It  has  been  attempted,  though  we 
think  very  unjustly,  to  detract  from  Con's  merits  as  an  original  inventor,  by  referring  to 
the  patents  of  John  Payne  and  Peter  Onions,  dated  respectively  21st  November,  1728, 
and  7th  xMay,  1783.  The  first  was  to  a  certain  extent,  undoubtedly,  a  patent  for  "roll- 
ing ;  "  for  the  bars  rendered  malleable  by  a  process  indicated,  are  "  to  pass  between  the 
large  nietall  rowUrs  which  have  proper  notches  or  furrows  upon  their  surface  ;"  but  there  is 
no  proof  that  any  practical  use  was  made  of  Payne's  process,  while  that  of  Cort  was  al- 
most immediately  and  universally  adopted  :  it  may  be  true,  therefore,  that  Cort  was  the 
rediscovcrcr  and  not  the  actual  discoverer  of  the  process  of  rolling,  but  this  in  no  way  de- 
tracts li  om  his  merit,  inasmuch  as,  by  his  improvements,  he  was  enabled  to  make  avail- 
able that  which  was  previously  useless.  The  same  observation  applies  to  the  patent  of 
Onions,  which  to  a  certain  extent  anticipated  that  of  Cort  for  puddling.  Onions  employ- 
ed two  furnaces — a  common  smeltir.g  furnace,  and  a  furnace  of  stone  and  brick,  bound  with 
iron  work  and  well  annealed,  into  which  the  Huid  metal  was  received  from  the  smelting 
furnace.  When  the  liquid  metal  had  been  introduced  into  the  second  furnace  by  an 
aperture,  it  was  closed  up  and  subjected  to  the  heat  of  fuel  and  blast  from  below,  unfil 
the  metal  became  less  fluid,  and  thickened  into  a  kind  of  paste;  tins  the  workman  by 
opening  a  door  turns  and  stirs  with  a  bar  of  iron,  and  then  closes  the  aperture  again, 
after  which  blast  and  fire  are  applied  until  there  is  a  ferment  in  the  metal;  the  adherent 
particles  of  iron  are  collected  into  a  mass,  reheated  to  a  white  heat,  and  forged  into 
malleable  iron.  That  the  process  of  puddling  is  here  indicated  there  can  be  no  doubt, 
but  the  Rctual  operation  was  impracticable  until  Henry  Cort  invented  the  furnace  in 
which  it  couhl  be  conducted. 

Neitlier  Mr.  Cort  nor  his  family  appear  to  have  derived  much  advantage  from  his 
important  discoveries — discoveries  which  changed  us  at  once  from  dependent  importers 
of  iron  into  vast  exporters  to  every  country  of  the  world,  and  which  may  be  considered 
to  have  founded  the  iron  industry  of  Great  Kritaia.  So  long  ago  as  1811,  the  chief  rep- 
resentatives of  the  trade  assembled  at  Gloucester  unanimously  acknowledged  their  in- 
del)tediiess  to  Mr  Cort  for  the  improvements  of  which  he  was  tiie  author,  and  this  acknowl- 
edgment has  been  repeated  witlnn  the  last  twelve  months  by  Hubert  Stcphe7t.'<o)i,  Fair- 
bairn,  Mawhla)!  and  Field,  Cubitt,  Reridel,  Sir  Charles  Fox,  BuUer,  Crawshay,  Bailetj, 
and  maiiv  others.  In  working  o\it  his  inventions,  Cort  is  said  to  have  expended  a  for- 
tune of  £2o,0()(>,  and  when  his  patents  were  completed,  the  leading  irimmasters  of  the 
country  contracted  to  pay  him  lo.f.  a  ton  for  their  use,  so  that  he  would  not  only  have 
been  repaid,  but  munificently  rewarded,  had  he  not  unfortunately  connected  himself  with  a 
man  named  Adam  Sellicoe,  chief  clerk  of  the  Navy  Pay  Office,  who  proving  to  be  a  de- 
faulter, committed  suicide,  having  previou.sly  destroyed  the  patents  and  the  agree- 
ments with  ironmasters  belonging  to  his  partner,  Henry  Cort.  Upon  the  death  of  Selli- 
coe, the  premises,  stock,  and  entire  eflects  of  Cort  were  soM  by  a  siunniary  iirocess  ob- 
tained bv  the  Navy  Pay  Ofllce,  and  the  unfortuiuite  man  was  thus  completely  ruined.  For 
description  of  puddling  furnace,  see  Iron,  vol.  i. 

The  I'uddlinij  process. — Various  patents  have  been  taken  out  within  the  last  four  or 
five  years  for  the  employment  of  chemical  agents  to  assist  in  the  i)urification  of  iron  in 
the  puddling  furnace.  One  of  the  latest  is  that  of  M.  Charles  Pauvert  of  Chatelleraidt, 
who  proposes  to  employ  a  cement  composed  of  the  following  substances: — oxide  of  iron, 
U  parts;  highly  alununous  clay,  30  parts;  carbonate  of  potash,  1  part;  carbonate  of 
soda,  1  i^art.  The  iron  is  to  be  placed  with  the  cement  in  layers,  and  heated  in  the  fur- 
nace in  the  ordinary  manner.  After  cementation  it  is  welded,  and  then  drawn  into  bars; 
it  is  stated  to  become  thus  as  soft  and  tenacious  as  iron  made  from  charcoal.  Shaf  haiult's 
compound,  for  which  a  patent  was  secured  in  1835,  is  said  by  Overman  to  furnish  very 
satisfactory  results,  and  where  competent  workmen  are  employed,  a  good  furnace  is  said 


IR02T.  661 

to  make  a  heat  in  two  hours,  producing  neither  too  much  nor  too  little  cinder  in  the  fur- 
nace. The  compound  consists  of  common  salt,  5  parts;  oxide  of  manganese,  3  parts; 
fine  white  plastic  clay,  2  parts.  The  pig  is  heated  as  in  common  operations.  It  is  melted 
down  by  a  rapid  heat,  the  damper  is  closed,  and  the  cinder  and  metal  diligently  stirred. 
In  the  mean  time  the  above  mixture,  in  small  parcels  of  about  half  a  pound,  is  introduced 
in  the  proportion  of  one  per  cent,  of  the  iron  employed;  if,  after  this,  the  cinder  doea 
not  rise,  a  hammer  slag  (rolling  mill  cinder)  may  be  applied. 

The  ^^  Boiling"  process. — In  this  operation,  which  was  the  invention  of  Mr.  Joseph 
Ilall,  pig  iron  is  converted  into  malleable  iron  without  the  intervention  of  the  refinery, 
and  without  any  excessive  waste:  it  is,  therefore,  of  great  value,  especially  as  it  allows 
of  the  use  of  better  qualities  of  pig  iron  than  those  usually  employed.  The  construction 
of  the  "boiling"  furnace  does  not  materially  differ  from  that  of  the  "puddling"  furnace, 
except  in  the  depth  of  the  hearth,  that  is,  in  the  distance  from  the  work  plate  below  the 
door  to  the  bottom  plate,  which,  in  the  former,  is  double,  or  nearly  so,  that  of  the 
latter.  In  the  puddling  furnace  the  distance  between  the  bottom  and  top  seldom  exceeds 
twenty  inches,  while  in  the  boiling  furnace  it  varies  from  twenty  to  thirty.  \\\  puddling 
the  furnace  is  charged  with  metal  alone,  but  in  boiling  cinder  is  charged  along  with  the 
metal,  and  the  temperature  rises  much  higher.  The  bottom  of  the  furnace  is  covered 
with  broken  cinders  from  previous  workings,  or  with  the  tap  cinder  from  the  puddling 
furnace  which  has  been  subjected  to  a  process  of  calcination  in  kilns;  this  material, 
which  constitutes  an  admirable  protection  to  the  iron  plates  of  the  furnace,  is  called  by 
t\ie  workmen  "  bull  dog  ; "  its  preparation  was  patented  by  Mr.  Hall  in  1839.  It  is  made 
in  the  following  manner  :  the  tap  cinder  from  the  paddling  furnace  is  placed  in  layers  in  a 
kiln,  and  so  arranged  that  a  draught  shall  pass  through  from  the  fire  holes  on  one  side 
to  those  on  the  other :  the  kiln  is  filled  up  to  the  top  with  broken  cinders,  and  over  the 
whole  is  laid  a  layer  of  coke  ;  about  the  third  or  fourth  day,  the  more  fusible  part  of  the 
cinder  begins  to  run  out  of  the  bottom  holes,  leaving  in  the  kiln  a  fine  rich  porous  silicate 
of  iron,  which  is  the  substance  used  for  lining  the  boiling  furnace,  the  fluid  portion  being 
rejected.  In  8  or  10  hours  the  "bull  dog"  is  melted  by  the  intense  heat  of  the  furnace, 
covering  the  bottom,  and  filling  up  all  the  interstices  in  the  brickwork  ;  the  heat  is  now 
somewhat  lowered  by  diminishing  the  draught,  and  the  charge  of  pig  (from  Z\  to  Ah  cwts.) 
introduced  in  fragments  of  a  convenient  and  uniform  size,  together  with  30  or  40  lbs.  of 
cinder ;  the  doors  of  the  furnace  are  now  closed,  and  all  access  of  cold  atmospheric  air 
prevented,  throwing  fine  cinder  or  hammer  slag  roimd  the  crevices,  and  stopping  up  the 
work  hole  with  a  piece  of  coaL  In  about  a  quarter  of  an  hour  the  iron  begins  to  get 
red-hot;  the  workman  then  shifts  the  pieces  so  as  to  bring  the  whole  to  a  state  of 
uniformity  as  regards  heat.  In  about  half  an  hour  the  iron  begins  to  melt ;  it  is  con- 
stantly turned  over,  and  at  intervals  of  a  few  minutes  cinder  is  thrown  in  ;  the  surface 
of  the  mass  is  seen  to  be  covered  with  a  blue  flame ;  it  soon  begins  to  rise  ;  a  kind  of 
fermentation  takes  place  beneath  the  surf\ice,  and  the  mass,  at  first  but  2  inches  high, 
rises  to  a  height  of  10  or  12  inches,  and  enters  into  violent  ebullition.  During  the  time 
that  this  "  fermentation"  is  taking  place,  constant  stirring  is  required  to  prevent  the  iron 
from  settling  on  the  bottom.  The  boiling  lasts  about  a  quarter  of  an  hour ;  after  which 
the  cinder  gradually  sinks,  and  the  iron  appears  in  the  form  of  porous  spongy  masses  of 
irregular  size,  which  are  constantly  stirred  to  prevent  their  adhering  together  in  large 
lumps,  to  facilitate  the  escape  of  the  carbon,  and  to  separate  the  cinder,  which,  when  the 
operation  has  been  successfully  conducted,  flows  over  the  bottom  apparently  as  liquid  as 
water.  The  iron  is  now  "  balled  up,"  as  in  the  operation  of  puddling.  The  objections 
to  the  boiling  process  are :  the  wear  and  tear  in  the  furnace  which  occurs  in  treating 
gray  pig  iron,  particularly  that  of  the  more  fluid  description  ;  the  slowness  of  the 
operation,  and  the  amount  of  manual  labor  which  it  entails  to  produce  good  results.  In 
some  works  the  crude  iron  is  run  directly  into  the  boiling  furnace  from  the  blast  furnace, 
by  which  nnich  saving  of  coal  is  effected,  and  a  product  of  a  more  uniform  quality 
obtained;  but  the  labor  of  the  workman  becomes  more  oppressive  from  the  additional 
heat  to  which  he  is  subjected  from  the  close  proximity  of  the  blast  furnace.  Ironmasters 
are  not  agreed  as  to  the  respective  merits  of  the  "boiling"  and  "puddling"  systems; 
some  maintain  that  the  former  is  more  economical  than  the  latter,  which  involves 
"  refining  ;  "  others  think  that  boiling  iron  has  a  tendency  to  communicate  to  it  the  "  red 
short"  quality.  According  to  the  observations  of  Mr.  Trnran,  in  several  works  where 
both  methods  are  employed,  the  largest  quantity  of  iron  is  first  passed  through  the 
refinery. 

Mr.  ITall,  the  inventor  of  the  boiling  system,  in  descanting  on  the  merits  of  his  pro- 
cess, describes  how,  with  the  same  pig.  the  iron  may  be  made  weak  and  cold  short ;  or 
tough,  ductile,  and  malleable.  For  the  first  proceed  thus  : — Pass  the  pig  through  the 
refinery,  then  puddle  agreeably  to  the  old  plan  on  the  sand  bottom  ;  that  is,  melt  it  as 
cold  as  possible;  drop  the  damper  quite  close  before  the  iron  is  all  tnelted,  dry  the  iron 
as  expeditiously  as  may  be,  with  a  large  quantity  of  water;  and,  lastly,  proceed  to  ball 


662 


lEON. 


in  a  proper  number  of  "young"  balls  ;  the  result  will  be  a  Tcry  inferior  quality  of  inanu- 
foctured  iron.  On  the  other  hand,  to  produce  a  malleable  iron  of  very  superior  quality 
first  charge  the  furnace  with  good  forge  pig  iron,  adding,  if  required,  a  sufficiency  of 
flux,  increasing  mr  diminishing  the  same  in  proportion  to  the  quality  and  nature  of  the 
pig  iron  used.  Secondly,  melt  the  iron  to  a  boiling  consistency.  Thirdly,  clear  the  iron 
thoroughly  before  dropping  down  the  damper.  Fourthly,  kce[)  a  plentiful  supply  of  fire 
upon  the  grate.  Fifthly,  regulate  the  drauglit  of  the  furnace  l)y  the  damper.  Sixthly, 
work  the  iron  into  one  mass,  before  it  is  divided  into  balls ;  when  thus  in  balls,  take  the 
whole  to  the  hammer  as  (luickly  as  possible,  after  which  roll  the  same  into  bars.  The 
bars,  being  cut  into  lengths,  and  piled  to  the  desired  weights,  arc  then  heated  in  the  mill 
furnace,  welded  and  compressed  by  passing  tlirough  the  rolls,  and  thus  furnished  ibr  the 
market.  In  this  way,  from  the  pig  to  the  finished  mill  bar,  one  entire  process,  that  of 
the  refinery,  is  saved.  Mr.  Hall  states  that,  by  his  process,  he  can  obtain  malleable  iron 
of  any  character,  (premising  that  the  ores  from  which  the  pig  is  smelted  are  of  good 
quality,)  from  tiie  softness  of  lead  to  the  hardness  of  steel,  and  further  that  he  can 
exhibit  difl'erent  qualities  in  the  same  bar,  one  end  being  crystalline,  nearly  as  brittle  as 
glass,  the  other  end  equal  to  the  best  iron  that  can  be  produced  for  fibre  and  tenacity, 
wliile  the  middle  exhibits  a  character  approximating  to  both  ;  and  as  a  further  illustration  of 
the  excellence  of  the  iron  that  may  be  made  by  the  "pig  boiling"  process,  he  refers  to 
a  specimen  in  the  Geological  Museum,  Jermyn  Street,  London,  labelled  "  Specimen  of 
two  and  a  quarter  inch  romid  iron,  tied  cold,  manufactured  at  the  Bloomfield  Iron  Works, 
Tipton,  Stiiilordshirc."  This  specimen  has  been  called  a  "  Staftbrdshire  knot  ;"  it  was 
made  from  a  bar  two  inches  and  a  quarter  in  diameter,  and  nearly  seven  inches  in  cir- 
cumference ;  also  to  a  "  Punched  Bar,"  half  inch  thick,  made  at  one  process  for  the 
smithy,  commencing  with  a  half-inch  punch,  and  terminating  with  one  six  and  a  half, 
without  exhibiting  the  slightest  fracture. 

Mr.  Hall  was  led  to  the  discovery  of  the  "boiling"  principle,  by  noticing  the  ex- 
ceedingly high  fusion  which  took  place  on  subjecting  puddling  furnace  slag  to  a  high 
degree  of  heat,  and  the  excellence  of  the  bloom  of  iron  produced  by  the  operation  ;  it 
occurred  to  him,  that  if  such  good  iron  could  be  made  from  cinder  alone,  a  very 
superior  product  ought  to  be  obtained  from  good  pig  iron,  with  equally  good  fluxes,  and 
the  result  of  experiments  fully  answered  his  expectation,  though  for  along  time  he  was 
unable  to  make  his  discovery  practically  useful,  on  account  of  the  difficulty  of  getting 
furnaces  constructed  capable  of  rendering  the  intense  heat  required,  and  the  corroding 
action  of  the  fluxes.  Puddling  furnaces  were  then  made  of  brick  and  clay,  with  sand 
bottoms.  He  succeeded  at  last  by  lining  the  interior  of  the  furnace  with  iron,  and  pro- 
tecting it  with  a  coating  of  prepared  tap  cinders. 

In  America,  the  "puddling"  and  "boiling"  processes  are  both  in  use.  Overman 
gives  preference  to  the  latter  as  being  the  most  profitable,  but  it  can  only  be  employed 
to  a  limited  extent  for  lack  of  cinder  ;  in  a  rolling  mill  forge,  therefore,  half  the  furnaces 
are  employed  for  boiling,  and  half  for  puddling,  the  latter  supplying  cinder  for  the  former. 
In  the  eastern  States,  where  the  fuel  is  anthracite,  double  puddling  furnaces  are  employed 
and  a  blast  is  used,  the  incombustibility  of  this  variety  of  coal  rendering  it  impossible  to 
get  the  requisite  heat  by  merely  the  draught  of  the  chimney.  lu/.  359  represents  an 

-  a59 


anthracite  furnace  bisected  vertically  through  the  grate,  hearth,  and  chimney.  It  differs 
from  the  ordinary  puddling  furnace  chiefly  in  the  greater  depth  of  the  grate,  which  is 
made  to  contain  from  twenty  to  twenty-four  inches  of  coal,  and  in  the  lesser  height  of 
the  chimney,  which,  as  a  blast  is  employed,  need  only  be  sufficiently  high  to  carry  the 


IKON. 


663 


hot  gases  out  of  the  furnace ;  the  letters  a,  a,  a,  a,  a,  indicate  the  position  of  the  iron 
cross  binders,  which  serve  to  bind  together  the  cast-iron  plates  of  the  enclosure,  and  to 
prevent  the  siuiiiiig  of  the  roof  from  the  expansion  and  contraction  of  the  brickwork. 

The  blast  machines  are  fans, 
the  best  form  of  which  is  shown  in  360 

Jiff.  360.  (Overman.)  The  wings 
of  this  fan  are  encased  in  a  sepa- 
rate box ;  a  wheel  is  thus  formed, 
which  rotates  in  the  outer  box  ;  the 
figure  shows  a  horizontal  section 
through  the  axis.  The  wings  are 
thus  connected,  and  form  a  closed 
wheel,  in  which  the  air  is  whirled 
round,  and  thrown  out  at  the  peri- 
phery. The  inner  case,  which  re- 
volves with  the  wings,  is  fitted  as 
closely  as  possible  to  the  outer 
case,  at  the  centre  near  a,  a,  a,  a. 
The  speed  of  the  wings  is  some- 
times as  much  as  1,S00  revolutions 
per  minute.     The  motion   of  the 

axis  is  produced  by  means  of  a  leather  or  india-rubber  belt  and  a  pulley.  This  variety  of 
fan  is  used  at  the  puddling  furnaces  at  Ebbw  Tale,  where  the  fuel  is  small  coal. 

Fig.  361  is  a  horizontal  section  of  the  double  anthracite  puddling  furnace.    The  grate 


measures  3  feet  by  5.  The  width  of  the  furnace  externally  is  from  5+  to  6  feet.  The 
hearth  is  usually  6  feet  in  length.  It  has  two  work  doors,  one  directly  opposite  the 
other.  Two  sets  of  workmen  are  required  therefore  at  the  same  time ;  double  the 
quantity  of  metal  is  charged,  and  the  yield  is  twice  that  of  a  single  furnace  ;  the  economy 
is  in  the  room,  fuel,  and  labor ;  one  good  puddler  only  being  required  to  manage  the 
operation.  Double  puddhng  furnaces  are  also  used  in  several  works  in  England,  but  as 
Mr.  Truran  observes,  the  economical  advantages  attending  them  in  point  of  fuel  are  lost 
if  the  pnddlers  do  not  work  well  to  time :  they  must  bring  their  heats  to  the  respective 
stages  simultaneously,  for  if  one  is  kept  waiting  for  a  short  period  by  the  other,  the  loss 
in  iron  more  thah  balances  the  reduced  consumption  of  coal.  This  difiiculty  of  obtain- 
ing men  who  will  work  well  in  concert  has  operated  against  the  use  of  the  double  furnace, 
which  would  otherwise  certainly  supersede  the  single,  as,  combined  with  the  process  of 
running  the  iron  in  liquid  from  the  blast  furnace,  the  consumption  of  fuel  is  under  the 
one-half  of  the  quantity  demanded  with  single  furnaces  working  cold  iron. 

Puddling  furnaces  are  sometimes  constructed  with  what  are  called  "  water  boshes." 
The  hearth  is  surrounded  with  heavy  cast-iron  plates,  in  which  is  formed  a  passage  of  an 
inch  or  an  inch  and  a  half  bore,  through  which  a  current  of  cold  water  is  caused  to  flow, 
the  object  being  to  protect  the  furnace  from  the  destructive  action  of  the  heat  and  cin- 
der. Overman  found  such  furnaces  to  work  well  with  fusible  metal  such  as  is  produced 
from  a  heavy  burden  on  the  blast  furnace,  or  from  ores  containing  phosphorus;  but 
with  iron  requiring  a  strong  heat,  such  as  results  from  a  light  burden  on  the  blast  fur- 
nace, or  when  it  contains  impurities  firmly  and  intimately  combined,  puddling  furnaces 
with  cooled  boshes  failed  to  make  good  malleable  iron. 

We  do  not  know  whether  the  iron  manufacturers  in  England  will  assent  to  the  fol- 
lowing proposition  laid  down  by  the  American  metallurgist,  v«.  :  "  That  the  smaller  the 
amount  of  coal  consumed,  or  the  lower  the  temperature  of  the  hearth  in  the  blast  furnace, 
the  better  will  be  the  quality  of  the  metal ;  that  is,  the  more  fit  it  will  become  for  im- 
provement in  the  puddUng  furnace.  The  advantage  of  heavy  burden  in  the  blast  furnace, 
is  not  only  that  it  reduces  the  first  cost  of  the  metal,  but  makes  a  far  superior  article  for 


664  IKON, 

subsequent  operations.  The  worst  cold  short,  or  sulphurous  metal,  smelted  by  a  low 
heat,  is  quite  as  good  as  the  best  metal  from  the  best  ore  smelted  by  a  high  temperature." 
Whatever  may  be  thought  of  the  latter  part  of  this  quotation,  no  iron  manufacturer  will 
deny  that  careful  attention  to  the  blast  furnace  is  the  best  security  of  success  in  the 
puddling  furnace,  and  that  success  in  the  one  is  in  proportion  to  the  economy  observed 
in  relation  to  the  other ;  or  that  it  is  hopeless  to  attempt  to  improve  in  the  puddling 
furnace  pig  iron  made  in  a  furnace  that  is  constantly  changing  its  burden  and  manage- 
ment ;  such  iron  is  most  advantageously  disposed  of  by  being  worked  up  into  coarse  bar 
or  railroad  iron. 

In  the  autumn  of  18.56  the  attention  of  ironmasters  and  of  the  public  generally  was 
powerfully  excited  by  a  jjroposal  from  Mr.  Bessemer  to  manufacture  iron  and  steel  from 
crude  iron,  without  any  fuel  at  all.  The  views  of  Mr.  Bessemer  were  first  communicated 
to  the  public  in  a  paper  read  by  that  gentleman  at  the  meeting  of  the  British  Associa- 
tion held  at  Cheltenham  in  August.  From  this  paper  the  following  extracts  are  taken, 
descriptive  of  the  apparatus  employed,  and  of  the  phenomena  attending  the  conversion: 

"The  furnace  is  acylindrical  vessel  of  three  feet  in  height,  somewhat  like  an  ordinary 
cupola  furnace,  the  interior  of  which  is  lined  with  fire-bricks;  and  at  about  two  inches 
from  the  bottom  are  inserted  fire  tuyere  pipes,  the  nozzles  of  which  are  formed  of  well- 
burnt  fire  clay,  the  orifice  of  each  tuyere  pipe  being  about  three-eighths  of  an  inch  in  di- 
ameter. These  are  so  put  into  the  brick  lining  (from  the  outer  side)  as  to  admit  of 
their  removal  or  renewal  in  a  few  minutes  when  they  are  worn  out.  At  one  side  of  the 
vessel,  about  half  way  up  from  the  bottom,  there  is  a  hole  made  for  running  in  the  crude 
metal ;  and  on  the  opposite  side  a  tap  bole  stopped  with  loam,  by  means  of  which  the 
iron  is  run  out  at  the  end  of  the  process.  The  vessel  is  placed  so  near  tlie  discharge 
hole  of  the  blast  furnace  as  to  allow  the  iron  to  flow  along  a  gutter  into  it.  A  small 
brass  cylinder  is  required,  capable  of  compressing  air  to  about  8  lbs.  or  10  lbs.  to  the 
square  inch.  A  communication  having  been  made  between  it  and  the  tuyeres,  the  con- 
verting vessel  is  in  a  condition  to  commence  work.  Previous,  however,  to  using  the 
cupola  for  the  first  time,  it  must  be  well  dried  by  lighting  a  fire  in  the  interior.  The 
tuyeres  are  situated  nearly  close  to  the  bottom  of  the  vessel ;  the  fluid  metal  rises,  there- 
fore, some  18  inches  or  two  feet  above  them.  It  is  necessary,  in  order  to  prevent  the 
metal  from  entering  the  tuyere  holes,  to  turn  on  the  blast  before  allowing  the  crude  iron  to 
run  into  the  vessel  from  the  blast  furnace.  This  having  been  done,  and  the  fluid  iron 
run  in,  a  rapid  boiling  up  of  the  metal  is  heard  going  on  within  the  vessel,  the  metal 
being  tossed  violently  about,  and  dashed  from  side  to  side,  shaking  the  vessel  by  the 
force  with  which  it  moves  from  the  throat  of  the  converting  vessel.  Flame  will  then  im- 
mediately issue,  accompanied  by  a  few  bright  sparks.  This  state  of  things  will  continue 
for  about  15  or  20  minutes,  during  which  time  the  oxygen  of  the  atmospheric  air  com- 
bines with  the  carbon  contained  in  the  iron,  producing  carbonic  acid  gas,  and  at  the 
same  time  evolving  a  powerful  heat.  Now  as  this  heat  is  generated  in  the  interior  of, 
and  is  diffused  in  innumerable  fiery  bubbles  through,  the  whole  fluid  mass,  the  metal 
absorbs  the  greater  part  of  it,  and  its  temperature  becomes  immensely  increased,  and  by 
the  expiration  of  15  or  20  minutes,  the  mechanically  mixed  carbon  or  graphite  has  been 
entirely  consumed.  The  temperature  is,  however,  so  high  that  the  chemically  combined 
carbon  now  begins  to  separate  from  the  metal,  as  is  at  once  indicated  by  an  immense 
increase  in  the  volume  of  the  flame  rushing  out  at  the  throat  of  the  vessel.  The  luetal 
now  rises  several  inches  above  its  natural  level,  and  a  light  frosty  sing  makes  its  appear- 
ance, and  is  thrown  out  in  large  foam-like  masses.  This  violent  eruption  of  cinder 
generally  lasts  5  or  6  minutes,  replacing  the  shower  of  sparks  and  cinder  which  always 
accompanies  the  boil. 

"The  rapid  union  of  carbon  and  oxygen  which  thus  takes  place,  adds  still  further  to 
the  temperature  of  the  metal,  while  the  diminished  quantity  of  carbon  present,  allows  a 
part  of  the  oxygen  to  combine  with  the  iron,  which  undergoes  combustion,  and  is  con- 
verted into  oxide,  at  the  excessive  temperature  that  the  metal  has  now  acquired  ;  the 
oxide,  as  soon  as  it  is  formed,  undergoes  fusion,  and  forms  a  powerful  solvent  of  those 
earthy  bases  that  are  associated  with  the  iron.  The  violent  ebullition  which  goes  on 
mixes  most  intimately  the  scoriiE  and  metal,  every  part  of  which  is  brought  into  contact 
with  the  fluid,  which  will  thus  wash  and  cleanse  the  metal  most  thoroughly  from  the 
silica  and  other  earthly  bases,  while  the  sulphur  and  other  volatile  matters  which  cling 
so  tenaciously  to  iron  at  ordinary  temperatures,  are  drawn  oft',  the  sulphur  combining 
with  the  oxygen  and  forming  sulphurous  acid  gas.  The  loss  in  weight  of  crude  iron 
during  its  conversion  into  an  ingot  of  malleable  iron  was  found  on  a  mean  of  four  ex- 
periments to  be  12i  per  cent.,  to  which  will  have  to  be  added  the  loss  of  metal  in  the 
finishing  rolls.  This  will  make  the  entire  loss  probably  not  le.«s  than  18  per  cent., 
instead  of  about  28  per  cent.,  which  is  the  loss  on  the  present  system.  A  large  portion 
of  that  metal  is,  however,  recoverable,  by  treating  with  carbonaceous  gases  the  rich  ox- 
ides thrown  out  of  the  furnace  during  the  boil.     These  slags  are  found  to  contain 


mOJ^".  665 

innumerable  small  grains  of  metallic  iron,  which  are  mechanically  held  in  suspension  in 
the  slags,  and  may  be  easily  recovered  by  opening  the  tap  hole  of  the  converting  vessel, 
and  allowing  the  fluid  malleable  iron  to  flow  into  tlie  iron  ingot  moulds  placed  there  to 
receive  them. 

"  The  masses  of  iron  thus  formed  will  be  perfectly  free  from  any  admixture  of  cinder, 
oxide,  or  any  other  extraneous  matters,  and  will  be  far  more  pure  and  in  a  sounder  state 
of  manufiicture  than  a  pile  formed  of  ordinary  puddled  bars.  And  thus  it  will  be  seen  that 
by  a  siugle  process,  requiring  no  manipulation  or  particular  skill,  and  with  only  one 
workman,  from  3  to  5  tons  of  crude  irou  passes  into  the  condition  of  several  piles  of 
malleable  iron  in  from  30  to  35  minutes,  with  the  expenditure  of  about  ^  of  the  blast  now- 
used  in  a  finery  furnace  with  an  equal  charge  of  iron,  and  with  the  consumption  of  no 
other  fuel  than  is  contained  in  the  crude  iron.  .  .  . 

"  One  of  the  most  important  facts  connected  with  this  new  system  of  manufacturing 
malleable  iron,  is  that  all  the  iron  so  prepared  will  be  of  that  quality  known  as  charcoal 
iron,  because  the  whole  of  the  processes  being  conducted  without  the  use  of  mineral  fuel, 
the  iron  will  be  free  from  those  injurious  properties  which  Jhat  description  of  fuel  never 
fails  to  impart  to  iron  that  is  brought  under  its  influence. 

"  At  that  stage  of  the  process  immediately  following  the  boil,  the  whole  of  the  crude 
iron  has  passed  into  the  condition  of  cast  steel  of  ordinary  quality.  By  the  continuation 
of  the  process,  the  steel  so  produced  gradually  loses  its  small  remaining  portion  of  carbon, 
and  passes  successively  from  hard  to  soft  steel,  and  from  soft  steel  to  steely  iron,  and 
eventually  to  very  soft  iron  ;  hence  at  a  certain  period  of  the  process  any  quality  of  metal 
can  be  obtained." 

The  phenomena  attending  this  novel  process  of  iron-making  are  very  well  described  in 
the  above  extract;  and  if  we  substitute  for  the  words  "a  few  bright  sparks,"  the  words 
'■  showers  of  bright  sparks,  poured  out  in  enormous  quantities,  projected  thirty  or  forty 
feet  into  the  air,  and  falling  on  all  sides  in  a  thick  shower,"  a  good  idea  may  be  formed  of 
the  gorgeous  display  of  pyrotechny  which  is  exhibited.  We  must  demur,  however,  to  the 
statement  that  "  the  sulphur  and  other  volatile  matters  present  in  the  crude  iron  are  drawn 
off;"  the  fact  being  that  the  sulphur  and  phosphorus  appear  to  have  suffered  little  if  any 
diminution,  notwithstanding  the  exces.^ive  temperature  and  tiie  powerful  oxidizing  action  to 
which  the  iron  has  been  subjected.  Thus  Mr.  Abel  found,  in  a  specimen  of  Mr.  Bessemer's 
product,  from  O'-t  to  0'5  per  cent,  of  phosphorus,  and  from  0'05  to  0  00  per  cent,  of  sul- 
phur ;  the  Blaenarvon  pig,  from  which  it  was  stated  to  have  been  prepared,  containing  O'S 
of  the  former  and  0'06  of  the  latter ;  and  in  a  sample,  broken  off  from  an  ingot  cast  at 
Baxter  House,  Sept.  1st,  1856,  on  which  occasion  we  were  present,  and  witnessed  the  whole 
process,  we  obtained  0'6  per  cent,  of  phosphorus  and  0'08  per  cent,  of  sulphur ;  similar 
results  have  been  obtained  by  other  chemists.  The  carbon  and  silicon,  on  the  other  hand, 
are  eliminated,  the  latter  wholly  so,  while  the  quantity  of  the  former  is  reduced  to  a  few 
hundredths  per  cent.  ;  we  think  also  that  Mr.  Bessemer  is  mistaken  in  stating  that  the  iron 
produced  by  his  method  contains  "  no  admixture  of  oxide,"  for  the  specimens  which  we 
have  had  an  opportunity  of  examining,  presented  unmistakable  evidence  of  partial  oxidation 
in  the  very  centre  of  the  ingot,  nor  do  we  see  how  it  could  well  be  otherwise. 

It  will  easily  be  imagined  that  a  process  which,  if  successful,  must  have  revolutionized 
the  whole  iron  manufacture,  was  speedily  subjected  to  a  most  careful  and  sifting  investiga- 
tion ;  and,  for  some  months  after  its  announcement,  the  papers  were  filled  with  communica- 
tions from  all  parts  of  the  country,  detailing  experiments  made  on  the  large  scale  to  test  its 
value  ;  the  results,  unfortunately  for  the  ingenious  projector,  were  unanimously  unfavorable. 
We  quote  first  from  the  "  Mining  Journal "  of  Xov.  29,  1856  : 

"  The  Dowlais  Company  appear  to  have  thoroughly  and  impartially  tested  Mr.  Besse- 
mer's process,  and  the  results  obtoined  can  only  be  regarded  as  a  total  failure A 

Bessemer  furnace  was  erected,  and  acted  excellently  as  far  as  the  process  was  concerned, 
but  failed  to  produce  any  thing  like  malleable  iron.  The  iron  used  was  from  clay-ironstone, 
Whitehaven  haematite,  and  small  portions  of  forge  cinders,  in  the  proportions  usually  em- 
ployed in  Wales  for  rails  and  merchant  iron.  After  the  metal  had  been  subjected  to  a  blast 
of  8  lbs.  pressure,  it  w;is  withdrawn  and  taken  to  the  '  squeezer,'  as  is  usual  with  puddled 
blooms,  to  take  out  the  dross  and  unite  the  particles  of  metal.  Instead  of  acting  like  pud- 
dled iron,  Mr.  Bessemer's  bloom  under  the  squeezer  was  a  mere  mass  of  red-hot  friable 
matter,  and,  from  its  crumbling  and  non-cohesion,  was  with  difficulty  formed  into  an  ingot : 
when  pa.ssed  through  the  rolls  it  broke  on  the  drawing  side  as  easily  as  very  '  red  short ' 
iron,  to  the  infinite  gratification  of  the  men,  who  greeted  each  failure  with  hearty  cheers. 
By  mixing  slag  with  the  metal,  a  slight  improvement  was  effected,  but,  on  being  submitted 
to  a  similar  manipulation,  it  was  found  to  be  no  better  than  '  cold  short'  iron." 

From  the  "  Cambrian,'  10th  Jan.,  1857  : — 

"  On  December  31st  the  Briton  Ferry  Iron  Company  received  two  of  Bessemer's  finest 
ingots  of  iron  to  test  its  value  after  passing  through  the  rolls.  Notwithstanding  every  care 
that  was  bestowed  on  the  process,  it  was  found  impossible  to  do  any  thing  with  it  to  the 


666  IROI"!". 

purpose,  and  the  manager  informs  us  that  old  rckit  iron,  after  passing  through  the  same 
process,  is  worth  by  at  least  £3  per  ton  more  than  that  tried  on  this  occasion." 

At  a  meeting  of  the  Polytechnic  Society  at  Liverpool,  Monday,  Sept.  16,  1856,  the 
chairman,  Edward  Jones  Eyre,  is  rejiorted  ("  Daily  News  ")  to  have  said  that  a  specimen 
of  Bessemer's  iron  had  been  received  and  tested  l)y  Jlr.  Clay  in  the  pi-escnce  of  Mr.  Daw-  ' 
son  and  himself,  and,  he  regretted  to  say,  had  been  far  from  satislactory  ;  the  specimen 
submitted  had  all  the  appearance  of  burned  and  itnjierfevt  cant-iron.  He  might  say  it  was 
rotten  hot  and  rotten  cold.  Mr.  Dawson  corroborated  this  statement,  and  also  said  that  he 
had  been  much  disappointed  in  the  result ;  the  portion  submitted  to  the  rolling  machine 
had  proved  in  every  way  intractable.  The  chairman  added,  that  he  hoped  ere  long  better 
results  would  be  obtained  ;  but  in  the  one  to  which  he  referred,  he  was  informed  that  the 
cast-iron  cost  £6  per  ton  originally,  and  after  being  operated  on,  as  he  saw  it,  he  did  not 
consider  it  worth  £4  per  ton. 

Lastly,  we  find  in  the  "  Mining  Journal  "  of  January  3d,  1857,  that  the  Bessemer  pro- 
cess was  tried  at  the  works  of  Messrs.  Jackson,  near  Glasgow.  The  usual  appearances  were 
noticed,  and  after  about  10  nanutes  the  furnace  was  tapped,  and  the  puiified  iron  ran  wliite 
and  limpid  into  moulds  prepared  for  the  purpose.  Alter  allowing  it  to  cool,  it  was  exam- 
ined ;  it  had  a  bright  silvery  whiteness  with  large  crystals,  but  was  exceedingly  brittle. 
When  rolled  it  preserved  the  same  crystalline  appearance  on  fracture,  but  in  a  state  of 
greater  compression  and  without  the  slightest  trace  of  fibre.  It  is  stated  to  have  been  deii- 
cient  in  every  quality  which  would  render  it  valuable  for  such  [)urposes  as  malleable  iron  is 
usually  applied  to — in  fact,  the  specimens  examined  were  not  malleable,  and  had  nothing 
of  tenacity  or  ductility,  properties  which  render  iron  valuable,  and  are  so  iudispen.sable  for 
the  mechanical  requirements  of  the  present  age. 

Although,  therefore,  it  is  scarcely  probable  that  fibrous  iron  will  ever  be  made  from 
metal  that  has  been  subjected  to  Bessemer's  treatment,  and  although  that  gentleman  was 
premature  in  announcing  his  invention  as  a  thing  proved  to  be  practical,  we  are  far  from 
asserting,  as  some  have  done,  that  the  time  of  iron  inasters  has  been  needlessly  occupied  in 
experimenting  on  the  subject,  or  that  no  good  is  likely  to  accrue  to  the  iron  manufacturer 
from  all  that  has  been  done  and  written  thereon.  The  extraordinary  tenacity  with  which 
iron  retains  sulphur  and  phosphorus  has  been  exhibited,  and  the  fact  that  we  must  resort  to 
other  oxidizing  agents  than  that  of  air  to  eliminate  them  has  been  demonstrated.  The  inju- 
rious effect  of  an  excessive  temperature  on  the  body  and  quality  of  iron  has  been  clearly 
manifested,  and  the  opinions  of  those  whose  experience  has  taught  them  that  it  is  vain  to 
look  for  the  production  of  a  tough  flexible  bar  from  iron  which  has  lost  nearly  the  whole 
of  its  carbon,  rapidly  or  without  manipulation,  has  been  confirmed.  It  is  more  than  prob- 
able, that  iron  containing  only  0  05  per  cent,  of  carbon,  has  almost  lost  the  property  of  be- 
coming fibrous  by  any  treatment ;  for  without  going  so  far  as  to  assert  that  the  develop- 
ment of  fibre  depends  on  the  presence  of  carbon,  or  that  carbon  exercises  a  specific  func- 
tion in  bringing  about  this  molecidar  condition  of  the  iron,  analysis  shows  that  the  toughest 
and  most  flexible  bar  iron  contains  a  far  larger  quantity  of  carbon  than  that  above  indicated, 
as  will  be  seen  by  the  following  analyses  by  Gay-Lussac,  "Willson,  Karsten,  and  Bromeis. 

Amount  of  Carbon  in  Bar  Iron. 

Carhon. 

Best  bar  iron  from  Sweden 0-293 

"  " 0-240 

Bar  iron  from  Crcusat 0-159 

Bar  iron  from  Champagne      ----. 0-193 

Bar  iron  from  Berry -         -         -         -         -0-162 

Cold  aJwrt  bar  iron  from  Moselle 0-144 

Soft  bar  iron  analyzed  by  Karsten 0-200 

Hard  bar  iron  by  Karsten 0-500 

Three  different  varieties  produced  from  white  pig  iron  by  the  Swabian  method 

of  refining,  analyzed  by  Bromeis       ..--.---  0-318 
Three  different  varieties  produced  from  white  pig  iron  by  the  Swabian  method 

of  refining,  analyzed  by  Bromeis 0-354 

Three  different  varieties  produced  from  white  pig  iron  by  the  Swabian  method 

of  refining,  analyzed  by  Bromeis       -         - 040 

Three  varieties  produced  from  various  kinds  of  pig  iron  by  the  Miigdesprung 

method  of  refining  -----------  0"324 

Three  varieties  produced  from  various  kinds  of  pig  iron  by  the  Miigdesprung 

method  of  refining  .         -         - 0-497 

Three  varieties  produced  from  various  kinds  of  pig  iron  by  the  Miigdesprung 

method  of  refining 0-CG 

It  will  be  noticed  that  the  smallest  amount  of  carbon  indicated  in  these  anal.vses  is 
nearly  three  times  greater  than  that  found  in  Bessemerized  iron,  and  in  this  specimen  the 


IROX. 


667 


iron  is  stated  to  be  "  cold  short,"  which  means  deficient  in  fibre  ;  it  is  probable  that  iron 
retains  the  last  portion  of  carbon  with  extraordinary  tenacity,  and  that  it  can  only  be  made 
to  yield  it  up  by  the  action  of  excessive  temperature  and  oxygen  ;  it  then  passes  into  a  con- 
dition of  what  is  called  burnt  iron,  which  Gmelin  states  (vol.  v.  p.  205,  Englixh  Transla- 
tion) is  the  only  variety  of  bar  iron  that  is  free  from  carbon.  This  is  clearly  the  condition 
of  the  ingots  made  by  Bessemer's  process ;  it  is  stated,  however,  that  by  proper  manage- 
ment any  desired  quantity  of  carbon  may  be  retained,  and  it  remains  to  be  proved  how  fur 
this  will  be  practicable  on  the  large  scale,  and  whether  those  varieties  of  steel  and  semi- 
steel  alluded  to  in  the  patents  can  really  be  produced. 

Some  interesting  experiments  on  fused  wrought  iron  have  recently  been  made  by  Mr. 
Riley  of  the  Dowlais  Iron  Works.  By  exposing  fragments  of  block  plate  from  the  tin 
works  for  two  hours  to  the  highest  heat  of  a  wind  furnace,  the  fragments  being  covered 
with  cinder  from  an  old  assay,  a  perfectly  fused  button  weighing  1,638  grains,  was  ob- 
tained. When  cold,  the  mass  was  crystallized  and  easily  broken,  the  fracture  being  in  tlie 
direction  of  the  planes  of  cleavage  of  the  crystals  ;  one  half  of  the  button  being  worked  out 
into  a  i  inch  bar  was  very  soft,  with  a  fine  face,  and  sharp  even  edges  like  steel ;  two 
pieces  when  welded,  worked  well  at  a  welding  heat,  but  on  cooling  to  a  red  heat  be- 
came cracky  and  broke.  The  fracture  of  the  iron  before  it  had  been  exposed  to  welding 
heat  was  silky  and  the  body  was  very  tough  ;  it  could  readily  be  bent  back  double  without 
cracking.  This  experiment  was  repeated  several  times,  with  similar  results,  the  fused  but- 
tons being  very  tough  and  fibrous  when  cold,  but  invariably  cracking  and  breaking  to 
pieces  after  having  been  subjected  to  a  welding  heat.  It  would  appear,  therefore,  that 
fused  wrought  iron  is  almost  a  worthless  substance.  Mr.  Riley  is  engaged  in  further  ex- 
periments, which,  it  is  to  be  hoped,  will  throw  some  light  on  this  singular  property  of  fused 
wrought  iron. 

Squeezers  are  machines  which  condense  a  ball  by  pressure.     They  are  either  single  or . 
double ;  their  construction  will  be  readily  understood  from  %.  362  which  represents  a 


single  level  squeezer  of  the  simplest  construction  ;  the  bed  plate  a  is  cast  in  one  piece  ;  it 
is  6  feet  long,  15  inches  wide,  and  12  inches  high.  The  whole  is  screwed  down  on  a  solid 
foundation  of  stone,  brick,  or  timber:  b  is  the  movable  part,  which  makes  from  80  to  90 
motions  per  minute.  The  motion  is  imparted  by  the  crank  c,  which  in  turn  is  driven  by 
means  of  a  strap  and  pulley  by  the  elementary  power.  The  diameter  of  the  fly  wheel  is 
from  3  to  4  feet.  The  anvil  d  is  about  two  feet  in  length,  and  from  12  to  14  inches  in 
width ;  it  is  a  movable  plate  at  least  3  inches  thick,  wiiich  if  injured  can  be  replaced  by 
another ;  the  face  of  the  working  part  of  the  lever  exactly  fits  the  anvil,  and  consists 
of  plates  attached  by  means  of  screws.  It  is  desirable  to  have  all  these  face  plates  in  small 
parts  of  8  or  10  inches  in  width  ;  by  this  means  they  are  secured  against  breaking  by  ex- 
pansion and  contraction.  The  whole  machine,  including  the  crank  and  every  thing,  is  mad6 
of  cast-iron,  and  weighs  from  4  to  5  tons.  According  to  Overman  this  machine  is  both 
clicap  and  durable,  .ind  will  squeeze  100  tons  of  iron  per  week. 

Fiff.  363  represents  the  double  squeezer,  employed  at  many  English  iron  works.  The 
drawing  is  taken  from  a  machine  at  the  Dowlais  Iron  Works,  figured  in  Mr.  Trurau's  work. 
Many  other  forms  are  in  use. 

Mff.  364  represents  Brown's  patent  bloom-squeezer.  Tlie  heated  ball  of  puddled  iron 
K,  thrown  on  the  top  is  gradually  pressed  between  the  revolving  rollers  as  it  descends,  and 
at  last  emerges  at  the  bottom,  where  it  is  t!n-own  on  to  a  movable  "  Jacob's  ladder,"  by 
which  it  is  elevated  to  the  rolls.  This  machine  effects  a  consiilcrable  saving  of  time,  will 
do  the  work  of  12  or  14  furnaces,  and  may  be  constantly  going  as  a  feeder  to  one  or  two 


668 


ieo:n". 


pairs  of  rolls.     There  are  two  distinct  forms  of  this  machine  ;  in  the  one  figured  the  bloom 
receives  only  two  compressions ;  in  another,  which  is  much  more  eflfective,  it  is  squeezed 


863 


four  times  before  it  leaves  the  rolls  and  falls  upon  the  Jacob's  ladder.     Another  form  of 
squeezer  is  shown  infff  365. 

A  table  a  a  with  a  lodge  rising  up  from  it  to  a  height  of  about  2  feet,  so  as  to  form  an 
open  box,  is  firmly  imbedded  in  masonry  ;  within  this  is  a  revolving  box,  c,  of  similar  char- 
acter, much  smaller  than  the  la?t,  and  placed  eccentrically  in  regard  to  it.  The  ball  or 
bloom  I)  is  placed  between  the  innermost  revolving  box  c  and  the  outer  case  a  a  where  the 
space  between  them  is  greatest,  and  is  carried  round  till  it  emerges  at  e,  compressed  and 
fit  for  the  rolls. 


365 


3GG 


IRON. 


669 


The  re-lieating  furnace  is  shown  in  section  injir/.  3fi6  ;  it  differs  but  little  from  a  puddling 
furnace.  The  whole  interior,  with  the  exception  of  the  hearth  a,  is  made  of  fire-brick  ;  the 
hearth  is  made  of  sand.  For  this  purpose  a  pure  siliceous  sand  is  required ;  the  coarser 
the  better.  The  hearth  slopes  considerably  towards  the  flue,  the  object  of  which  is  to 
keep  the  hearth  dry  and  hard.  Tiie  iron  wasted  in  re-heating  combines  with  the  silica  of 
the  sand,  forming  a  very  fusible  cinder,  which  flows  ott"  through  the  opennig  at  h,  at  which 
there  is  a  small  flre  to  keep  the  cinder  liquid.  The  thickness  of  the  sand  bottom  is  from  6 
to  12  inches,  resting  on  fire-brick  :  it  generally  requires  re-making  after  two  or  three  heats. 
Tiie  height  of  the  fire-brick  arch,  or  its  distance  from  the  sand  bottom,  is  from  8  to  l"i 
inches.  The  area  of  the  fire-place  averages  12  feet,  and  the  width  of  the  furnace  varies 
from  5  to  8  feet.  When  the  piles  are  charged  into  the  furnace,  the  door  is  shut,  and  fine 
coal  is  dusted  around  its  edges  to  exclude  the  cold  air ;  the  temperature  is  raised  to  the 
highest  intensity  as  quickly  as  possible,  and  the  workman  turns  the  piles  over  from  time  to 
time  that  they  may  be  brought  to  an  uniform  welding  heat  in  the  shortest  possible  time. 

It  is  thought  by  many  that  a  purer  iron  is  obtained  by  subjecting  the  balls  as  they  come 
out  of  the  puddling  furnace  to  the  action  of  the  hammer  at  first,  rather  than  to  the  roughing 
rollers,  as  by  the  latter  process  vitrified  specks  remain  in  the  metal,  which  the  hammer  ex- 
pels. Hence  in  some  works  the  balls  are  first  worked  under  the  forge  hammer,  and  these 
stampings  being  afterwards  heated  in  the  form  of  pies  or  cakes,  piled  over  each  other,  are 
passed  through  the  roughing  mills. 

Bars  intended  for  boiler  or  tin  plates  are  made  from  the  best  cold  blast  mine  iron.  The 
raw  pig  is  refined  in  the  usual  manner  with  coke,  the  loss  amounting  to  from  2^  to  3  cwls. 
per  ton.  It  is  then  refined  a  second  time  with  charcoal,  the  loss  amounting  again  to  from 
2.V  to  3  cwts.  per  ton.  After  this  second  refining  it  is  beaten  into  flat  plates  white  hot  by 
the  tilt  hammer  and  thrown  into  cold  water ;  the  sudden  chilling  makes  it  more  easily 
broken  into  small  slabs.  The  slabs  are  piled  in  heaps  and  welded  in  the  hollow  fire,  coke 
being  the  fuel ;  the  slabs  are  laid  across  the  fire,  and  do  not  come  into  contact  with  the 
fuel ;  the  blast  is  thrown  under  the  fuel,  and  the  heat  is  immense  ;  when  the  piles  are  nearly 
at  the  fusing  point,  they  are  withdrawn  and  passed  under  the  rollers  ;  they  are  again  heated 
in  the  hollow  fire,  then  again  rolled  and  heated  a  third  time  in  the  ordinary  reverberatory 
furnace,  after  which  they  are  drawn  out  into  flat  bars  for  boiler  plates,  or  for  tin  plates:  the 
loss  in  these  operations  amounts  to  from  3i  to  4  cwts.  per  ton.  About  9  heats  are  accom- 
plished in  12  hours,  each  heat  consisting  of  2^  cwts.  of  refined  metal,  and  consuming  5 
baskets  of  charcoal. 

The  bars  intended  for  tin  plates  are  repeatedly  heated  and  rolled  until  of  the  requisite 
thinness ;  the  plates  are  then  cut  into  squares,  and  annealed  by  exposing  them  for  several 
hours  to  heat  in  covered  iron  boxes,  being  allowed  to  cool  very  slowly ;  this  gives  the  plates 
the  proper  degree  of  pliancy.  The  next  operation  is  that  of  pickling ;  the  plates  are  im- 
mersed in  dilute  sulphuric  acid  for  the  purpose  of  removing  from  their  surfaces  all  oxide 
and  dirt ;  after  remaining  in  the  acid  for  the  requisite  time,  they  are  thoroughly  washed  in 
successive  troughs  of  water,  and  then  dried  in  sawdust ;  finally,  the  surfaces  of  the  metal 
are  prepared  for  the  reception  of  the  tin,  by  rubbing  them  with  leather  upon  cushions  of 
sheepskin.  The  spent  sulphuric  acid  is  run  out  into  evaporating  pans,  and  the  sulphate  of 
iron  crystallized  out.  In  order  to  tin  the  plates,  they  are  immersed  in  a  bath  of  melted  tin, 
the  surface  of  which  is  covered  with  tallow  or  palm  oil ;  when  sufficiently  covered,  they 
are  transferred  to  the  briixhcr  on  the  loft-hand  side  of  the  tinner  ;  he  passes  a  rough  brush 
rapidly  over  each  side  of  the  plate,  wherc!)y  the  superfluous  tin  is  removed  ;  he  then  plunges 
the  plate  again  into  the  tin  bath,  and  passes  it  on  to  his  left-hand  neighbor,  who  gives  it  a 
washing.  The  plate  passes  through  several  hands  before  it  is  dried.  Great  skill  is  required 
in  the  tinning  process ;  nevertheless  in  a  well-conducted  work  the  wasters  do  not  amount 
to  more  than  10  per  cent.  ;  a  small  percentage  of  which  are  so  bad  as  to  require  to  be  re- 
worked. (Jreat  care  is  taken  to  avoid  waste,  tin  being  worth  150/.  per  ton.  A  box  of  22,5 
sheets  of  tin  plates,  10  inches  by  14,  consumes  about  8i  lbs.  of  tin.     See  Tin  Plate. 

Drg  assa>/  of  iron  ores. — The  object  of  a  drg  assag  of  an  iron  ore  is  to  ascertain  by  an 
experiment  on  a  small  scale  the  amount  of  iron  which  the  ore  should  yield  when  smelted  on 
the  large  scale  in  the  blast  furnace.  For  this  purpose,  the  metal  must  be  deoxidized,  and 
such  a  temperature  produced  as  to  melt  the  metal  and  the  earths  as.sociated  with  it  in  the 
ore,  so  that  the  former  may  be  obtained  in  a  dense  button  at  the  bottom  of  the  crucible,  and 
the  latter  in  a  lighter  glass  or  slag  above  it.  Such  a  temperature  can  only  be  obtained  in  a 
wind  furnace  connected  with  a  chimney  at  least  30  feet  in  height,  and  when  made  expressly 
for  assaying  the  furnace,  is  generally  built  of  such  a  size  that  four  as.says  may  be  made  at 
the  same  time,  viz.  about  14  inches  sciuaro,  anil  2  feet  in  depth  from  the  un<ler  side  of  the 
cover  to  the  movablt;  bars  of  iron  whioli  form  the  grate.  In  order  that  the  sul)stances 
associated  with  the  iron  in  the  ore  should  form  a  fusible  compound,  it  is  usually  requisite  to 
add  a  flux,  the  natm-e  of  which  will  depend  upon  the  character  of  the  ore  under  examina- 
tion. Berthier  divides  iron  ores  into  five  classes:  1.  The  almost  pure  oxides,  such  as  the 
magnetic  oxide,  oligistic  iron,  and  the  hccinatites  ;   2.  Ores  containing  silica,  but  free  or 


670  IRON. 

nearly  so  from  any  other  admixture  ;  3.  Ores  containing  silica  and  various  bases,  but  little 
or  no  lime ;  4.  Ores  containing  one  or  more  bases,  such  as  limf^  macfnena,  alumina,  oxide 
of  manqancxe,  oxide  of  titanium,  oxide  of  tantalum,  oxide  of  chromium,  or  oxide  of  tung- 
sten, but  little  or  no  silica;  5.  Ores  containing  silica,  lime,  and  another  base,  and  which 
are  I'usible  alone.  Ores  of  the  first  class  may  be  reduced  without  any  flux,  but  it  is  always 
better  to  employ  one,  as  it  greatly  facilitates  tl;e  formation  of  the  button ;  borax  may  be 
used,  or,  better,  a  fusible  eaitliy  silicate,  such  as  ordinary  flint  glass.  Ores  of  the  second 
class  require  some  base  to  serve  as  a  flux,  such  as  carbonate  of  soda,  a  mixture  of  carbonate 
of  lime  and  clay,  or  of  carbonate  of  lime  and  dolomite  :  ores  of  the  thiid  class  are  mixed 
with  carbonate  of  lime  in  the  proportion  of  from  one-half  to  three-fourths  of  the  weight 
of  the  foreign  matter  present  in  the  ore.  Ores  of  the  fourth  class  require  as  a  flux  silica  in 
the  form  of  pounded  quartz,  and  generally  also  some  lime  ;  the  manganesian  spathic  ores 
which  belong  to  this  class  may  be  assayed  with  the  addition  of  silica  alone,  but  the  mag- 
nesian  spathic  ores  require  lime.     Ores  of  the  fifth  class  require  no  flux. 

Method  of  conductihfi  the  assay. — One  hundred  grains  of  the  ore  finely  pulverized  and 
passed  through  a  silk  sieve  are  well  mixed  with  the  flux,  and  the  mixture  intioduced  into 
the  smooth  coucavity  made  in  the  centre  of  a  crucible  that  has  been  lined  with  charcoal  ; 
the  lining  of  the  crucible  is  effected  liy  partially  filling  it  with  coarsely  powdered  and 
slightly  damped  charcoal  or  brasijve,  which  is  then  rammed  into  a  solid  foim  l)y  the  use  of 
a  light  wooden  pestle.  The  mirigled  ore  and  flux  must  be  covered  with  charcoal.  The 
crucible  thus  filled  is  closed  with  an  earthen  lid  luted  on  with  fire  clay  ;  and  it  is  then 
set  on  its  base  in  the  air  furnace.  The  heat  should  be  very  slowly  raised,  the  damper  re- 
maining closed  during  the  first  half-hour.  In  this  way,  the  water  of  the  damp  charcoal  ex- 
hales slowly,  and  the  deoxidation  of  the  ore  is  completed  before  the  fusion  begins  ;  if  the 
heat  were  too  high  at  first,  the  luting  would  piobably  split,  and  nun  cover,  the  slag  foimcd 
would  dissolve  some  oxide  of  iron,  which  would  be  lost  to  the  button,  and  thus  give  an 
erroneous  result.  After  half  an  hour,  the  damper  is  gradually  opened,  and  the  fumace 
being  filled  with  fresh  coke,  the  temperature  is  raised  piogressivcly  to  a  white  heat,  at 
which  i)itch  it  must  be  maintained  for  a  quarter  of  an  hour ;  the  damper  is  then  closed  and 
the  furnace  is  allowed  to  cool.  As  soon  as  the  temperature  is  sufficiently  reduced,  the  cru- 
cible is  removed  and  opened  over  a  sheet  of  brown  paper ;  the  Irasqv.e  is  carefully  removed, 
and  the  button  of  cast-iiou  taken  out  and  weighed.  If  the  experiment  has  been  entirely 
successful,  the  iron  will  be  found  at  the  bottom  of  the  crucible  in  a  small  rounded  button, 
and  the  slag  will  be  entirely  fiee  fiom  any  adhciing  rrctallic  globules,  and  will  reseml  le  in 
appearance  green  bottle  glass ;  should,  however,  the  slag  contain  small  metallic  particks, 
the  experiment  is  not  necessarily  a  fiiilure,  as  they  may  generally  be  recovered  by  washing 
and  the  magnet.  But  if,  on  breaking  the  c;  ucible,  the  reduced  metal  should  be  found  in  a 
partiallv  melted  state,  and  not  collected  into  a  distinct  mass,  it  indicates  either  too  low  a 
temperature  or  an  improper  selection  effluxes,  and  the  experiment  must  be  repeated.  The 
iron  obtained  is  not  chemically  pure,  but  contains  caibon,  and  if  the  ore  is  manganiferous, 
manganese  ;  the  residt  is  therefore  somewhat  too  high,  though  indicating  with  sufficient 
exactness  for  all  manufacturing  purposes,  the  lichness  of  tl:e  ore  assayed. 

Humid  assni/  of  iron  ores. — The  ciuantitative  determination  of  the  various  substances 
that  occur  in  iron  ores,  demands  on  the  part  of  the  operator  a  ccnsiderable  amount  of  skill 
and  patience,  and  can  only  be  profitably  undertaken  by  those  who  have  acquired  in  the 
laboratory  a  thorough  acquaintance  with  analytical  operations.  As,  however,  much  atten- 
tion has  of  late  years  been  bestowed  on  the  composition  of  iron  ores,  and  as  certain  ele- 
ments, viz.  manf/nnese,  sulphnr.  and  phosphorus,  are  frequently  present,  which  very  con- 
siderably affect  their  commercial  value,  wo  deem  it  right  to  give  a  detailed  account  of  the 
operations  to  be  performed  in  order  to  arrive  at  an  accurate  knowledge  of  the  composition 
of  an  ore. 

Taking  for  illustration  a  specimen  of  the  most  complicated  composition,  the  substances 
besides  iron  to  be  looked  for,  and  estimated,  are  uafer,  ^]n!(|ro^co],iv  and  combined,)  organic 
matter,  sulphur,  (as  suljihuric  rtci'e/,  and  as  bisulphide  rf  iro7t,)  phosphoric  acid,  carbonic 
acid,  silicic  acid,  oxide  of  maneiaiiese,  alumina,  lime,  and  alkalies;  lead,  tin,  copper,  and 
arsenic  arc  also  occasionally  met  with  ;  these  metals  are  sought  for  when  a  suspicion  of 
their  presence  is  entertained  by  a  special  operation  on  a  large  quantity  of  ore. 

Too  great  care  cannot  be  bestowed  on  the  samplinri  of  ores  intended  for  analysis  ;  to 
expend  so  much  time  and  labor  on  an  isolated  specimen  (unless  for  a  special  oVjcct)  is  worse 
than  u.seless ;  the  sample  operated  upon  should  be  selected  from  a  laige  heap,  w  hich  .«hould 
be  thoroughly  gone  over,  and  several  dozen  piece's  taken  from  different  paits ;  these  should 
be  coarsely  powdered  and  n.ixed,  and  about  half  a  pound  taken  from  the  mass  should  be 
preserved  in  a  well-corked  bottle  for  examination. 

1.  Determination  of  irater,  (hi/fn'onojiic  and  combined.) — About  50  grains  of  the  ore  are 
dried  in  the  water  oven  till  no  further  loss  of  weight  is  expeiienced  ;  the  loss  indicates  the 
hygroscopic  water ;  the  residue  is  introduced  into  a  tube  of  hard  glass,  to  which  is  adapted 
a  weighed  tube  containing  chloride  of  calcium  ;   the  powder  is  then  gradually  raised  to  a 


IRO:s.  671 

low  red  heat,  the  combined  water  is  thereby  expelled,  and  its  amount  determined  by  the 
'  increase  in  weight  of  the  chloride  of  calcium  tube.     Some  ores  (the  hydrated  haematites) 
contain  as  much  as  12  per  cent,  of  combined  water. 

2.  Sulphuric  acid  and  sul/jhur. — From  3u  to  50  grains  of  the  ore  are  digested  with 
hydrochloric  acid,  filtered  and  washed.  The  filtrate,  concentrated  if  necessary  by  evapora- 
tion, is  precipitated  by  great  excess  of  chloride  of  barium.  Every  100  parts  of  the  sulphate 
of  baryta  produced,  indicate  3437  parts  of  sulphuric  acid.  The  insoluble  residue  on  the 
filter  is  fused  in  a  gold  crucible  with  nitre  and  carbonate  of  soda,  the  fused  mass  is  dis- 
solved in  hydrochloric  acid,  evaporated  to  dryness,  moistened  with  strong  acid,  diluted 
and  filtered ;  from  the  filtiate  the  sulphuric  acid  is  precipitated  as  sulphate  of  baryta, 
every  lUO  parts  of  which  indicate  13748  parts  of  sulphur,  and  25.48  parts  of  bisulphide 
of  iron. 

In  the  analysis  of  haematites  it  is  necessary  to  bear  in  mind,  that  perchloride  of  iron  is 
partially  reduced  when  boiled  with  finely  divided  iron  pyrites  and  hydrochloric  acid,  sul- 
phuric acid  being  formed. — Dick. 

PhfiUfthoric  acid. — From  5M  to  75  grains  of  the  ore  are  digested  with  hydrochloric  acid 
and  filtered  ;  the  clear  solution,  whieii  should  not  be  too  acid,  is  boiled  with  suljihite  of 
ammonia,  added  gradually  ia  small  quantities  till  it  either  becomes  colorless,  or  acquires  a 
pale  green  color,  indicating  that  the  peroxide  of  iron  originally  present  has  been  reduced 
to  protoxide ;  the  solution  is  nearly  neutralized  with  carbonate  of  ammonia,  excess  of 
acetate  of  ammonia  added,  and  the  liquid  boiled  ;  strong  solution  of  perchloride  of  iron  is 
then  added  drop  by  drop,  until  the  precipitate  which  forms  has  a  distinct  red  color ;  this 
precipitate,  which  contains  all  the  phosphoric  acid  originally  present  in  the  ore,  is  collected 
on  a  filter,  washed,  and  redissolved  in  hydrochloric  acid,  tartaric  acid  added,  and  then  am- 
monia. From  this  ammoniacal  solution,  the  phosphoric  acid  is  finally  precipitated  as  am- 
monio-phosphate  of  magnesia,  by  the  addition  of  chloride  of  ammonium,  sulphate  of  mag- 
nesia, and  ammonia.  The  precipitate  is  allowed  24  hours  to  subside,  it  is  then  collected  on 
a  filter,  and  if  it  has  a  yellow  color,  which  is  almost  invariably  the  case,  it  is  redissolved  in 
hydrochloric  acid,  and  more  tartaric  acid  being  added,  it  is  again  precipitated  by  ammo- 
nia :  100  parts  of  the  ignited  pyrophosphate  of  magnesia  correspond  to  64.3  parts  of  phos-, 
phoric  acid. 

Alkalies. — It  was  ascertained  by  Mr.  Dick,  that  nearly  the  whole  of  the  alkali  present 
in  an  iron  ore  is  contained  in  that  portion  which  is  insoluble  in  hydrochloric  acid. 
The  residue  from  about  50  grains  of  the  ore  is  placed  in  a  platinum  capsule,  moistened 
with  ammonia,  and  exposed  for  several  hours  to  the  action  of  hydrofluoric  acid  gas 
in  a  closed  leaden  dish  ;  it  may  be  necessary  to  repeat  the  operation  if  much  silica  is  pres- 
ent ;  it  is  then  slowly  heated  to  dull  redness,  and  dissolved  in  dilute  hydrochloric  acid ; 
the  solution  is  mixed  with  excess  of  baryta  water  and  filtered  ;  the  excess  of  baryta  is  re- 
moved by  carbonate  of  ammonia,  and  the  solution  is  evaporated  to  dryness  and  ignited; 
the  residue  is  redissolved  in  a  little  hot  water,  and  a  few  drops  of  oxalate  of  ammonia  added. 
If  no  precipitate  or  cloudiness  occurs,  it  may  be  once  more  evaporated  to  dryness  and  gently 
ignited  :  the  residue  is  chloride  of  potassium,  100  parts  of  which  indicate  63  parts  of  potash. 
Should  oxalate  of  ammonia  have  occasioned  a  precipitate,  it  must  be  filtered  oft',  and  the 
clear  liquid  evaporated.  The  search  for  potash  is  troublesome  and  lengthy ;  it  may  be  alto- 
gether omitted  in  a  technical  analysis. 

Determination  of  the  remaininr/  constituents. — 25  or  30  grains  of  the  finely  powdered 
ore  are  digested  for  about  half  an  hour  with  strong  hydrochloric  acid,  diluted  with  lioiling 
distilled  water  and  filtered.  The  residue  on  the  filter  being  thoroughly  washed,  the  solution 
is  peroxidized,  if  necessary,  by  the  addition  of  chlorate  of  pota^sh,  nearly  neutralized  by 
ammonia,  boiled  with  excess  of  acetate  of  ammonia,  and  rapidly  filtered  while  hot ; 
the  filtrate,  (which  should  be  colorless,)  together  with  the  washings,  is  received  in  a  flask, 
ammonia  is  added,  and  then  a  few  drops  of  bromine,  and  the  flask  closed  with  a  cork. 
In  a  few  minutes,  if  manganese  be  present,  the  liquid  acquires  a  dark  color ;  it  is  allowed 
to  remain  at  rest  for  24  hours,  then  warmed,  and  rapidly  filtered  and  washed ;  the  brown 
substance  on  the  filter  is  hydrated  oxide  of  manganese  :  it  loses  its  water  by  ignition,  and 
then  becomes  Mn'O*,  100  parts  of  which  correspond  to  93  parts  of  protoxide. 

The  liquid  filtered  from  the  manganese  contains  the  lime  and  magnesia ;  the  former  is 
precipitated  by  oxalate  of  ammonia,  and  the  oxalate  of  lime  formed  converted  by  ignition 
intn  carbonate,  in  which  state  it  is  either  weighed,  having  been  previously  evaponited  with 
carbonate  of  ammonia,  or  it  is  converted  into  sulphate  by  the  addition  of  a  few  drops  of 
sulphuric  acid,  evaporation,  and  ignition.  The  lime  being  separated,  the  magnesia  is  thrown 
down  as  ammonio-magnesian  phosphate  by  phosphate  of  soda  and  ammonia,  and  after  stand- 
ing for  24  hours  it  is  collected  on  a  filter,  washed  with  cold  ammonia  water,  dried,  ignited, 
and  weighed  ;  100  parts  of  carbonate  of  lime  correspond  to  oG'O  of  lime ;  100  parts  of 
sulphate  of  lime  to  40"1  of  lime,  and  luO  parts  of  pyrophosphate  of  magnesia  to  35"7  of 
magnesia. 

The  red  precipitate  collected  on  the  filter  after  the  boiling  with  acetate  of  ammonia. 


G72  IRON. 

consists  of  the  basic  acetates  of  iron  and  alumina,  together  with  the  phosphoric  acid.  It 
is  dissolved  in  a  small  quantity  of  hydrochloric  acid,  and  then  boiled  in  a  silver  or  platinum 
basin  with  considerable  excess  of  pure  caustic  potash  ;  the  alumina  (with  the  phosphoric 
acid)  is  hereby  dissolved,  the  insoluble  portion  is  allowed  to  subside,  and  the  clear  liquid  is 
then  decanted,  after  which  the  residue  is  thrown  on  a  filter  and  washed ;  the  filtrate  and 
washings  are  supersaturated  with  hydrocliloric  acid,  nearly  neutralized  with  ammonia,  and 
the  alumina  finally  precipitated  by  carbonate  of  ammonia.  From  the  weight  of  the  ignited 
precipitate,  the  corresponding  amount  of  phosphoric  acid  determined  by  a  separate  operation 
is  to  be  deducted,  the  remainder  is  calculated  as  ahnnina.  The  residue  left  after  digesting  the 
ore  with  hydrochloric  acid,  consists  principally  of  silica,  but  it  may  also  contain  almnina, 
peroxide  of  iron,  lime,  magnesia,  and  potash.  For  practical  purposes  it  is  rarely  necessary 
to  submit  it  to  minute  examination ;  should  such  be  desired,  it  must  be  dried,  ignited, 
and  weighed,  then  fused  in  a  platinum  crucible  with  four  times  its  weight  of  mixed  alka- 
line carbonates,  the  fused  mass  dissolved  in  dilute  hydrochloric  acid,  and  evaporated  to 
dryness,  the  residue  moistened  with  strong  hydrochloric  acid,  and  after  standing  at  rest 
for  some  hours,  digested  with  hot  water,  filtered,  and  the  silica  on  the  filter  ignited  and 
weighed.  The  ahnnina,  lime,  oxide  of  iron,  and  magnesia  in  the  filtrate  are  separated  from 
each  other  according  to  the  instructions  given  above ;  ihe  potasfi  is  estimated  ))y  a  distinct 
process. 

Carbonic  acid. — This  acid,  which  constitutes  a  considerable  part  of  the  weight  of  that 
large  and  important  class  of  ores  the  clay  ironstones,  is  estimated  by  noting  the  loss  sus- 
tained after  adding  to  a  weighed  portion  of  the  ore  sulphuric  acid,  and  thus  evolving  the 
gas  ;  or  more  roughly,  by  the  loss  sustained  in  the  entire  analysis.  Another  method  is  to 
fuse  20  or  25  grains  of  the  ore  with  60  or  80  gi-ains  of  dry  borax,  and  noting  the  loss,  which 
consists  of  water  and  carbonic  acid  ;  by  deducting  the  water  obtained  in  a  previous  experi- 
ment, the  quantity  of  carbonic  acid  is  obtained.  This  method,  however,  can  scarcely 
be  recommended,  on  account  of  the  corrosion  of  the  crucible,  though  the  results  are  very 
accurate. 

Determination  of  the  iron. — This  is  performed  on  a  separate  portion  of  the  ore,  either 
>by  the  volumetric  method  of  Marguerite,  or  by  that  of  Dr.  Penny :  both  give  very  exact 
results.  Marguerite's  method  is  based  on  the  reciprocal  action  of  the  salts  of  protoxide  of 
iron  and  permanganate  of  potash,  whereby  a  quantity  of  the  latter  is  decomposed  exactly 
proportionate  to  the  quantity  of  iron.  The  ore  (about  10  or  15  grains)  is  dissolved  in  hydro- 
chloric acid,  and  the  metal  brought  to  the  minimum  of  oxidation  by  treating  the  solution 
with  suljjhite  of  soda,  (or  better,  sulphite  of  ammonia,)  and  boiling  to  expel  the  excess  of 
sulphurous  acid ;  the  solution  of  permanganate  of  potash  is  then  cautiously  added  drop  by 
drop,  until  the  pink  color  appears,  and  the  number  of  divisions  of  the  burette  required  for 
the  purpose  accurately  noted.  The  solution  should  be  considerably  diluted,  and  there  must 
be  a  sufficient  quantity  of  free  acid  present  to  keep  in  solution  the  peroxide  of  iron  formed 
and  also  the  oxide  of  manganese.  The  whole  of  the  iron  must  be  at  the  minimum  of 
oxidation,  and  the  excess  of  sulphurous  acid  must  be  completely  expelled ;  if  the  latter 
precaution  be  neglected,  an  erroneous  result  will  be  obtained,  as  the  sulphurous  acid  will 
itself  take  oxygen  from  the  permanganic  acid,  and  thus  react  in  the  same  manner  as  iron. 

To  prepare  the  permanganate  of  potash,  7  parts  of  chlorate  of  potassas,  10  parts  of 
hydrate  of  potassa,  and  8  parts  of  peroxide  of  manganese  are  intimately  mixed.  The 
manganese  must  be  in  the  finest  possible  powder,  and  the  potash  having  been  dissolved  in 
water,  is  mixed  with  the  other  substances,  dried,  and  the  whole  heated  to  very  dull  redness 
for  an  hour.  The  fused  mass  is  digested  with  water,  so  as  to  obtain  as  concentrated  a  solu- 
tion as  possible,  and  dilute  nitric  acid  added  till  the  color  becomes  of  a  beautiful  violet ;  it 
is  afterwards  filtered  through  asbestos.  The  solution  must  be  defended  from  the  contact 
of  organic  matter,  and  kept  in  a  glass  stoppered  bottle.  If  the  solution  be  evaporated,  it 
yields  beautiful  red  acicular  crystals :  it  is  better  to  employ  the  crystals  in  the  preparation 
of  the  test  liquor,  as  the  solution  keeps  much  better  when  no  manganatc  is  present.  To 
prepare  the  normal  or  test  liquor,  a  certain  quantity,  say  15  grains,  of  piano-forte  wire  is 
dissolved  in  pure  hydrochloric  acid  ;  after  the  disengagement  of  hydrogen  has  ceased,  and 
the  solution  is  complete,  the  liquor  is  diluted  with  about  a  pint  of  water,  and  accurately 
divided  by  measurement  into  two  cfjual  parts,  the  number  of  burette  divisions  of  the  solu- 
tion of  permanganate  required  to  produce  in  each  the  pink  color  is  accurately  noted  ;  and 
this  number  is  then  employed  to  reduce  into  weight  the  result  of  the  analysis  of  an  ore.  A 
useful  normal  liquor  is  made  by  dissolving  100  grains  of  the  crystallized  permanganate  in 
10,000  grains  of  water. 

Penny's  method  is  based  on  the  reciprocal  action  of  chromic  acid  and  protoxide  of  iron, 
whereby  a  transference  of  oxygen  takes  place,  the  protoxide  of  iron  becoming  converted 
into  peroxide,  and  the  chromic  acid  into  sesquioxide  of  chromium.  The  process  is  con- 
ducted as  follows  :  A  convenient  quantity  of  the  specimen  is  reduced  to  coarse  powder,  and 
one-half  at  least  of  this  is  still  further  pulverized  until  it  is  no  longer  gritty  between  the 
fingers.     The  test  solution  of  bichromate  of  potash  is  next  prepared  :  44  4  grains  of  this 


IKON.  673 

salt  in  fine  powder  are  weighed  out,  and  put  into  a  burette  graduated  into  100  equal  parta, 
and  warm  distilled  water  is  afterwards  poured  in  until  the  instrument  is  filled  to  0.  The 
palm  of  the  hand  is  then  securel_y  placed  on  the  top,  and  the  contents  agitated  by  repeatedly 
inverting  the  instrument  until  the  salt  is  dissolved  and  the  solution  rendered  of  uniform 
density  throughout.  Each  division  of  the  solution  thus  prepared  contains  0'4-44  grains  of 
bichromate,  which  Dr.  Penny  ascertained  to  correspond  to  half  a  grain  of  metallic  iron. 
The  bichromate  must  be  pure,  and  should  be  thoroughly  dried  by  being  heated  to  incipient 
fusion.  100  grains  of  the  pulverized  iron-stone  are  now  introduced  into  a  Florence  tiask 
with  H  oz.  by  measure  of  strong  hydrochloric  acid  and  i  oz.  of  distilled  water.  Heat  is 
cautiously  applied,  and  the  mixture  occasionally  agitated  until  the  effervescence  caused  by 
the  escape  of  carbonic  acid  ceases ;  the  heat  is  then  increased,  and  the  mixture  made  to  boil, 
and  kept  at  moderate  ebullition  for  ten  minutes  or  a  quarter  of  an  hour.  About  6  oz.  of 
water  are  next  added  and  mixed  with  the  contents  of  the  flask,  and  the  whole  filtered  into  an 
evaporating  basin.  The  flask  is  rinsed  several  times  with  water,  to  remove  all  adhering 
sohition,  and  the  residue  on  the  filter  is  well  washed.  Several  small  portions  of  a  weak 
solution  of  red  prussiate  of  potash  (containing  1  part  of  salt  to  40  water)  are  now  dropped 
upon  a  white  porcelain  slab,  which  is  conveniently  placed  for  testing  the  solution  in  the 
basin  during  the  next  operation.  The  prepared  solution  of  bichromate  of  potash  in  the 
burette  is  then  added  very  cautiously  to  the  solution  of  iron,  which  must  be  repeatedly 
stirred,  and  as  soon  as  it  assumes  a  dark  greenish  shade  it  should  be  occasionally  tested 
with  the  red  prussiate  of  potash.  This  may  be  easily  done  by  taking  out  a  small  quantity 
on  the  end  of  a  glass  rod,  and  mixing  it  with  a  drop  of  the  solution  on  the  porcelain  slab. 
When  it  is  noticed  that  the  last  drop  communicates  a  distinct  blue  tinge,  the  operation  is 
terminated  ;  the  bui-ette  is  allowed  to  drain  for  a  few  minutes,  and  the  number  of  divisions 
of  the  test  liquor  consumed  read  off.  This  number  multiplied  by  2  gives  the  amount  of 
iron  per  cent.  The  necessary  calculation  for  ascertaining  the  corresponding  quantity  of 
protoxide  is  obvious.  If  the  specimen  should  contain  iron  in  the  form  of  peroxide,  the 
hydrochloric  solution  is  deoxidized  as  before  by  sulphite  of  ammonia.  The  presence  of 
peroxide  of  iron  in  an  ore  is  easily  detected  by  dissolving  30  or  40  grains  in  hydrochloric 
acid,  diluting  with  water,  and  testing  a  portion  of  the  solution  with  sii/phoci/anide  of  potaa- 
siinn.  If  a  decided  blood-red  color  is  produced,  peroxide  of  iron  is  present.  If  it  be 
desired  to  ascertain  the  relative  proportions  of  peroxide  and  i)rotoxide  of  iron  in  an  ore, 
two  operations  must  be  performed  :  one  on  a  quantity  of  the  ore  that  has  been  dissolved  in 
hydrochloric  acid  in  a  stout  stoppered  bottle  ;  and  another  on  a  second  quantity  that  has 
been  dissolved  as  usual,  and  then  deoxidized  by  sulphite  of  ammonia  or  of  metallic  zinc.  It 
is  advisable  to  employ  the  solution  of  bichromate  much  weaker  than  proposed  by  Dr.  Penny, 
and  to  employ  a  burette  graduated  to  cubic  millimetres.  A  good  strength  is  1  grain  of 
metallic  iron  =:  10  cubic  centimetres  of  bichromate. 

Metals prccipitahle  by  sidphurcttcd  Iii/drogenfrom  tlie  hydrochloric  solution. — A  weighed 
portion  of  the  ore  varying  from  200  to  2,000  grains  is  digested  for  a  considerable  time 
in  hydrochloric  acid  ;  the  solution  is  filtered  off;  the  iron  in  the  filtrate  reduced  when 
necessary  by  sulphite  of  ammonia,  and  a  current  of  sulphuretted  hydrogen  passed 
through  it.  A  small  quantity  of  sulphur  which  is  always  suspended  is  collected  on  a 
filter  and  thoroughly  washed;  it  is  then  incinerated  at  as  low  a  temperature  as  possible. 
Tlie  residue  (if  any)  is  mixed  with  carbonate  of  soda  and  heated  upon  charcoal  before 
tlie  blowpipe  ;  any  globules  of  metal  that  may  be  obtained  are  dissolved  and  tested. 

Analysis  of  pig  iron. — The  most  important  constituents  to  be  determined  am  car- 
bon, (combined  and  uncombiued,)  silicon,  sulphur,  phosphorus  ;  those  of  less  consequence, 
or  of  more  rare  occurrence,  are  manganese,  arsenic,  copper,  zinc,  chromium,  titanium, 
cobalt,  nickel,  tin,  aluminium,  calcium,  magneslion,  and  the  metals  of  the  alkalies. 

1.  Determination  of  the  total  ainount  of  carbon. — About  100  grains  of  the  iron  in  small 
pieces  are  digested,  at  a  moderate  temperature,  in  C-oz.  measures  of  a  solution  formed 
by  dissolving  6  oz.  of  crystallized  sulphate  of  copper,  and  4  oz.  of  common  salt  in  20  oz. 
of  water  and  2  oz.  of  concentrated  hydrochloric  acid.  Tlie  action  is  allowed  to  proceed 
until  all,  or  nearly  all  the  iron  is  dissolved.  Carbon  and  copper  are  left  insoluble  ;  these 
are  collected  on  a  filter,  and  washed  first  with  dilute  hydrochloric  acid,  (to  prevent  the 
precipitation  of  subchloride  of  copper,)  then  with  water,  then  with  dilute  caustic  potash, 
and  finally  with  boiling  water.  The  mixed  carbon  and  copper  are  dried  on  the  filter, 
from  which  they  are  easily  removed  by  a  knife-blade,  and  are  mixed  with  oxide  of  cop- 
per, and  burned  in  a  combustion  tube  in  the  usual  way,  with  a  current  of  air,  or,  still 
better,  of  oxygen.  The  carbonic  acid  is  collected  in  Liebig's  apparatus,  from  which  the 
amount  of  carl)on  is  calculated. 

2.  Graphite,  or  uncombined  carbon. — A  weighed  portion  of  the  finely  divided  iron 
(filings  or  borings  may  be  used)  is  digested  with  moderately  strong  hydrochloric  acid ; 
the  combined  carbon  is  evolved  in  combination  with  hydrogen,  while  the  graphite  is  left 
undissolved.  It  is  collected  on  a  filter,  washed,  and  then  boiled  wiih  a  solution  of  caustic 
potash,  sp.  gr.   \-21,  in  a  silver  dish  ;  the  silica  which  existed  in  the  iron  in  the  form  of 

Vol.  III.— 43 


674  IRON. 

silicon  is  hereby  dissolved;  the  clear  caustic  solution  is  drawn  off  by  a  pipe  or  syphon, 
and  the  black  residue  repeatedly  washed ;  it  is  dried  at  as  high  a  temperature  as  it  will 
bear,  and  weighed  ;  it  is  then  heated  to  redness  in  a  current  of  air,  until  the  whole  of 
the  carbon  is  burnt  off.  A  reddish  residue  generally  remains,  which  is  weighed,  and  the 
weight  deducted  from  that  of  original  black  residue ;  the  difference  gives  the  amount  of 
graphite. 

3.  Silicon. — The  amount  of  this  element  is  determined  by  evaporating  to  dryness  a 
hydrochloric  solution  of  a  weighed  quantity  of  the  metiil :  the  dry  residue  is  redigested 
with  hydrochloric  acid,  diluted  with  water,  boiled  and  filtered ;  the  insoluble  matter  on 
the  filter  is  washed,  dried,  and  ignited,  until  the  whole  of  the  carbon  is  boiled  off;  it  is 
then  weighed,  after  which  it  is  digested  with  solution  of  potash,  and  the  residue,  if  any, 
washed,  dried,  ignited,  and  weighed :  the  difference  between  the  two  weights  gives  the 
amount  of  silicic  acid,  100  parts  of  which  indicate  47  parts  of  silicon. 

PhosphoriLx. — A  weighed  portion  of  the  metal  is  digested  in  nitro-hydrochloric  acid, 
evaporated  to  dryness,  and  the  residue  redigested  with  hydrochloric  acid.  The  solution 
is  treated  precisely  as  recommended  for  the  determination  of  phosphoric  acid  in  ores ; 
every  100  parts  of  pyrophosphate  of  magnesia  indicate  '28'50  parts  of  phosphorus. 

Sulphur. — In  gray  iron  tliis  element  is  very  conveniently  and  accurately  estimated  by 
allowing  the  gas  evolved  by  the  action  of  hydrochloric  acid  on  a  weighed  quantity  (about 
100  grains)  of  the  metal,  in  filings  or  borings,  to  pass  slowly  througli  a  solution  of  acetate 
of  lead  acidified  by  acetic  acid :  the  sulphur,  the  whole  of  which  takes  the  form  of  sul- 
phuretted hydrogen,  enters  into  combination  with  the  lead,  forming  a  black  precipitate 
of  sulphide  of  lead,  which  is  collected,  washed,  and  converted  into  sulphate  of  lead  by 
digesting  it  with  nitric  acid,  evaporating  to  dryness,  and  gently  igniting:  iOO  parts  sul- 
phate of  lead  r=  10-5.5  sulphur.  The  most  minute  quantity  of  sul])liur  in  iron  is  detected 
by  this  process.  If,  however,  crude  while  iron  is  under  examination,  this  method  does 
not  give  satisfactory  results,  on  account  of  the  difficulty  with  which  it  is  acted  upon  by 
hydrochloric  acid;  it  is  better,  therefore,  to  treat  the  metal  with  nitro-hydrochloric  acid, 
evaporated  to  dryness,  redigest  with  hydrochloric  acid,  and  then  precipitate  the  filtered 
solution  with  great  excess  of  chloride  of  barium ;  or  the  finely  divided  metal  may  be 
fused  in  a  gold  crucible  with  an  equal  weight  of  pure  iiitrate  of  soda  and  twice  its  weigiit 
of  pure  alkaline  carbonates  ;  the  fused  mass  is  extracted  with  water  acidified  with  hydro- 
chloric acid,  and  finely  precipitated  by  chloride  of  barium. 

Manffanese. — This  metal  is  determined  by  the  process  described  for  its  estimation  in 
ores ;  the  iron  must  exist  in  the  solution  in  the  form  of  sesquioxide. 

Arsenic  and  copper. — The  nitro-hydrochloric  solution  of  the  metal  is  evaporated  to 
dryness,  redigested  with  hydrochloric  acid,  and  filtered.  The  iron  in  the  clear  solution 
is  reduced  to  protochloride  by  boiling  with  a  sufficient  quantity  of  sulphite  of  ammonia, 
the  solution  is  boiled  till  it  has  lost  all  smell  of  sulphurous  acid.  It  is  then  saturated 
with  sulphuretted  hydrogen,  and  allowed  to  stand  for  24  hours  in  a  closed  vessel,  the 
excess  of  gas  is  boiled  off,  and  the  precipitate,  if  any,  collected  on  a  small  filter  and  well 
washed ;  it  is  digested  with  monosulphide  of  potassium,  which  dissolves  th.e  sulpliide  of 
arsenic,  leaving  the  sulphide  of  copper  untouched;  the  latter  is  decomposed  by  heating 
with  nitric  acid,  and  the  presence  of  copper  evinced  by  the  addition  of  ammonia,  which 
produces  a  fine  blue  color;  the  sulphide  of  arsenic  is  precipitated  from  its  solution  in 
sulphide  of  potassium  by  dilute  sulphuric  acid;  it  may  be  redissolvcd  in  arp(a  regia,  and 
the  nitric  acid  having  been  expelled  by  evaporation,  the  arsenic  may  be  reduced  in 
Marsh's  apparatus. 

Nickel  and  cobalt.-~-The?e  metals,  if  present,  will  be  found  in  the  solution  from  which 
the  copper  and  arsenic  have  been  precipitated  by  sulphuretted  hydrogen.  The  solution 
is  peroxidized,  and  the  sesquioxide  of  iron  precipitated  by  slight  excess  of  carbonate  of 
baryta,  after  which  the  nickel  and  cobalt  are  precipitated  by  sulphide  of  ammonium. 

Chromium  and  vanadium. — These  metals,  which  should  be  looked  for  in  the  car- 
bonaceous residue  obtained  by  dissolving  a  large  quantity  of  the  iron  in  dilute  hydro- 
chloric or  sulphuric  acid,  are  detected  as  follows  ( \Vi:hler) : — Tlie  ignited  residue  is  inti- 
mately mixed  with  one-tliird  of  its  weight  of  nitre,  and  exposed  for  an  hour  in  a  crucil)Ie 
to  a  gentle  ignition.  When  cool,  the  mass  is  powdered  and  boiled  with  water.  The 
filtered  solution  is  gradually  mixed  and  well  stirred  with  nitric  acid,  taking  care  that  it 
may  still  remain  slightly  alkaline,  and  that  no  nitrous  acid  is  liberated  which  would  reduce 
the  vanadic  and  chromic  acids.  The  solution  is  then  mixed  with  an  excess  of  solution 
of  chloride  of  barium  as  long  as  any  precipitate  is  produced.  The  precipitate,  which 
consists  of  vanadiate  and  chromate  of  baryta,  is  decomposed  with  slight  excess  of  dilute 
sulphuric  acid,  and  filtered.  The  filtrate  is  ncutnilized  with  ammonia,  concentrated  by 
evaporation,  and  a  fragment  of  chloride  of  ammonium  placed  in  it.  In  proportion  as 
the  solution  becomes  saturated  with  chloride  of  ammonium,  vanadate  of  ammonia  is 
deposited  as  a  white  or  yeUow  crystalline  powder.  To  test  for  chromium  only,  the  mass 
after    fusion  with  nitre  is  extracted  with  water,   and   then  boiled  with  carbonate  of 


IVORY,  FICTILE.  675 

ammonia  ;  the  solution  is  neutralized  with  acetic  acid,  and  then  acetate  of  lead  added ;  the 
production  of  a  yellow  precipitate  indicates  c/iromic  acid. 

Aluminium. — This  metal  is  best  separated  from  iron  by  first  reducinjf  the  latter  to 
the  state  of  protoxide  by  sulphite  of  ammonia,  then  neutralizing  with  carbonate  of  soda, 
and  afterwards  boiling  with  excess  of  caustic  potash  until  the  precipitate  is  black  and 
pulverulent.  The  solution  is  then  filtered  off,  slightly  acidulated  with  hydrochloric  acid, 
and  the  alumina  precipitated  by  sulphide  of  ammonium. 

Calcium  and  magnesium. — These  metals  are  found  in  the  solution  from  which  tlie  iron 
and  aluminium  have  been  separated ;  they  both  exist  probably  (together  with  the 
aluminium)  in  the  cast  iron  in  the  form  of  slag,  and  are  best  detected  in  the  black  residue 
which  is  left  on  dissolving  the  iron  in  dilute  sulphuric  or  hydrochloric  acid.  After 
digesting  this  residue  with  caustic  potash,  and  burning  away  the  graphite,  a  small 
quantity  of  a  red  powder  is  left,  which  is  composed  of  sUicic  acid,  oxide  of  iron,  alumina, 
lime,  and  magnesia;  if  500  grains  of  cast  iron  are  operated  upon,  a  sufficient  quantity 
of  insoluble  residue  will  be  obtained  for  a  quantitative  determination  of  its  constituents. 
— H.  M.  N. 

IVORY.  It  is  not  our  intention  to  enter  into  the  consideration  of  the  handicrafts  em- 
ploying ivory,  but  a  short  account  of  the  methods  of  preparing  this  beautiful  material, 
which  we  extract  from  HoltzapfePs  Mechanical  Manipulations,  will  be  of  value. 

"  On  account  of  the  great  value  of  ivory,  it  requires  considerable  judgment  to  be  em- 
ployed in  its  preparation,  from  three  conditions  observable  in  the  form  of  the  tusk ;  fii-st, 
its  being  curved  in  the  direction  of  its  length  ;  secondly,  hollow  for  about  half  that  extent, 
and  gradually  taper  from  the  solid  state  to  the  thin  feather  edge  at  the  root ;  and  thirdly, 
elliptical  or  irregular  in  section.  These  three  peculiarities  give  rise  to  as  many  separate 
considerations  in  cutting  up  the  tooth  with  the  requisite  economy,  as  the  only  waste  should 
be  that  arising  from  the  passage  of  the  thin  blade  of  the  saw  :  even  the  outside  strips  of 
the  rind,  called  spills,  are  employed  for  the  handles  of  penknives,  and  many  other  little 
objects  ;  the  scraps  are  burned  in  retorts  for  the  manufiicture  of  ivory  black,  employed  for 
making  ink  for  copperplate  printers,  and  other  uses ;  and  the  clean  sawdust  and  shavings 
are  sometimes  used  for  making  jelly. 

"  The  methods  of  dividing  the  tooth,  either  into  rectangular  pieces  or  those  of  a  circular 
figure  required  for  turning,  are  alike  in  their  early  stages,  until  the  lathe  is  resorted  to. 
The  ivory  saw  is  stretched  in  a  steel  frame  to  keep  it  very  tense  ;  the  blade  generally  meas- 
ures from  fifteen  to  thirty  inches  long,  from  one  and  a  half  to  three  inches  wide,  and  about 
the  fortieth  of  an  inch  thick  ;  the  teeth  are  rather  coarse,  namely,  about  five  or  six  to  the 
inch,  and  they  are  sloped  a  little  forward,  that  is,  between  the  angle  of  the  coiumon  hand- 
saw tooth  and  the  cross-cut  saw.  The  instrument  should  be  very  sharp,  and  but  slightly 
set ;  it  requires  to  be  guided  very  correctly  in  entering,  and  with  no  more  ])ressure  than 
the  weight  of  its  own  frame,  and  is  commonly  lubricated  with  a  little  lard,  tallow,  or  other 
solid  fat. 

"  The  cutter  begins  generally  at  the  hollow,  and  having  fixed  that  extremity  parallel 
with  the  vice,  with  the  curvature  upwards,  he  saws  off  that  piece  which  is  too  thin  for 
his  purpose,  and  then  two  or  three  parallel  pieces  to  the  lengths  of  some  particular  works, 
for  which  the  thickness  of  the  tooth  at  that  part  is  the  most  suitable  ;  he  will  then  saw  off 
one  very  wedge-form  piece,  and  afterwards  two  or  three  more  parallel  blocks. 

"  In  setting  out  the  length  of  every  section,  he  is  guided  by  the  gradually  increasing 
thickness  of  the  tooth  ;  having  before  him  the  patterns  or  images  of  his  various  works,  he 
will  in  all  cases  employ  the  hollow  for  the  thickest  work  it  will  make.  As  the  tooth  ap- 
proaches the  solid  form,  the  consideration  upon  this  score  gradually  ceases,  and  then  the 
blocks  are  cut  off  to  any  required  measure,  with  only  a  general  reference  to  the  distribution 
of  the  heel,  or  the  excess  arising  from  the  curved  nature  of  the  tooth,  the  cuts  being  in 
general  directed  as  nearly  as  may  be  to  the  imaginary  centre  of  curvature.  The  greater 
waste  occurs  in  cutting  up  very  long  pieces,  owing  to  the  dilference  between  the  straight 
line  and  the  curve  of  the  tooth,  on  which  account  the  blocks  are  rarely  cut  more  than  five 
or  six  inches  long,  ujiless  for  some  specific  object." 

IVORY,  FICTILE,  is  plaster  of  Paris  which  has  been  made  to  absorb,  after  drying, 
melted  spermaceti,  by  capillary  action,  or  it  luay  be  prepared  according  to  Mr.  Franchi's 
process  as  follows :  Plaster  and  coloring  matter  are  employed  in  the  proportions  of  a 
pound  of  superfine  plaster  of  Paris  to  half  an  ounce  of  Italian  yellow  ochre.  They  are 
intimately  mixed  by  passing  them  through  a  fine  silk  sieve,  and  a  plaster  cast  is  made  in 
the  usual  way.  It  is  first  allowed  to  dry  in  the  open  air,  and  is  then  carefully  heated  in  an 
oven  ;  the  plaster  cast,  when  thoroughly  dry,  is  soaked  for  a  quarter  of  an  hour  in  a  bath 
containing  equal  parts  of  white  wax,  spermaceti,  and  stearine,  heated  just  a  little  lieyond 
the  melting  point.  The  cast  on  removal  is  set  on  edge,  that  the  supertluons  composition 
may  drain  off,  and  before  it  cools,  the  surface  is  brushed,  with  a  brush  like  that  known  by 
house  painters  as  a  sa-sh  tool,  to  remove  any  wax  which  may  have  settled  in  the  crevices; 
and  finally  when  the  plaster  is  quite  cold,  its  surfiicc  is  polished  by  rubbing  it  with  a  tuft 
of  cotton  wool. 


676  JAPANNING. 


JAPANNING  is  a  kind  of  varnishing  or  lacquering,  practised  with  excellence  by  the 
Japanese,  whence  the  name. 

The  only  difference  between  varnishing  and  japanning  is  that  after  the  application  of 
every  coat  of  color  or  varnish,  the  object  so  varnished  is  placed  in  an  oven  or  stove  at  as 
high  a  temperature  as  can  safely  be  employed  without  injuring  the  articles  or  causing  the 
vainish  to  blister  or  run. 

For  black  japanned  works,  the  ground  is  first  prepared  with  a  coating  of  black,  made 
by  mixing  dross  ivory  black  to  a  proper  consistence  with  dark-colored  anime  varnish,  as 
this  gives  a  blacker  surface  than  could  be  produced  by  japan  alone.  If  the  surface  is  re- 
quired to  be  polished,  five  or  six  coats  of  japan  are  necessary  to  give  sufficient  body  to  pre- 
vent the  japan  from  being  rubbed  through  in  polishing. 

Colored  japans  are  made  by  mixing  with  some  hard  varnishes  the  required  color,  and 
proceeding  as  described.     See  Varnish,  vol.  ii. 

JET.  (Jaiet,  ovjais,  Fr.)  Jet  occurs  in  the  upper  lias  shale  in  the  neighborhood  of 
Whitby,  in  Yorkshire,  in  which  locality  this  very  beautiful  substance  has  been  worked  for 
many  hundred  years.  The  jet  miner  searches  with  great  care  the  slaty  rocks,  and  finding 
the  jet  spread  out,  often  in  extreme  thinness  between  the  laminations  of  the  rock,  he  fol- 
lows it  with  great  care,  and  frequently  he  is  rewarded  by  its  thickening  out  to  two  or  three 
inches. 

The  best  jet  is  obtained  from  a  lower  bed  of  the  upper  lias  formations.  This  bed  has  an 
average  thickness  of  about  20  feet,  and  is  known  as  jet  rock.  An  inferior  kind,  known  as 
soft  jet,  is  obtained  from  the  upper  part  of  the  upper  lias,  and  from  the  sandstone  and  shale 
above  it.  The  production  of  jet  in  this  country  appears  to  be  limited  to  the  coast  of  York- 
shire, from  about  nine  miles  south  of  Whitby  to  Boulby,  about  the  same  distance  to  the 
north  ;  the  estates  of  Lord  Mulgrave  being  especially  productive.  There  is  a  curious  allusion 
tothis  in  Drayton's  Polyolbion  : — 

The  rocks  by  Moultarave,  too,  my  glories  forth  to  set, 
Out  of  their"  crannied  rocks  can  give  you  perfect  jet. 

Dr.  Young,  in  his  Geology  of  the  Yorkshire  Coast,  writes : — "  Jet,  which  occurs  here  in 
considerable  quantities  in  the  aluminous  Vjed,  may  be  properly  classed  with  fossil  wood,  as 
it  appears  to  be  vood  in  a  high  state  of  bitumerdzation.  Pieces  of  wood  impregnated  with 
silex  are, often  found  completely  crusted  with  a  coat  of  jet  about  an  inch  thick.  But  the 
most  common  form  in  which  the  jet  occurs  is  in  compact  masses  of  from  half  an  inch  to  two 
inches  thick,  from  three  to  eighteen  inches  broad,  and  of  ten  or  twelve  feet  long.  The 
outer  surface  is  always  marked  with  longitudinal  striae,  like  the  grain  of  wood,  and  the 
transverse  fracture,  which  is  conchoidal,  and  has  a  resinous  lustre,  displays  the  annual 
growth  in  compressed  elliptical  zones.  Many  have  supposed  this  substance  to  be  indurated 
petroleum^  or  animal  pitch  ;  but  the  facts  now  quoted  are  sufficient  to  prove  its  ligneous 
origin." 

It  does  not  appear  to  us  that  the  "  ligneous  origin  "  of  jet  is  by  any  means  established  ; 
indeed  we  think  the  amount  of  evidence  is  against  it.  There  is  no  example,  as  far  as  we 
can  learn,  of  any  discovery  of  true  jet  having  a  strictly  ligneous  structure,  or  showing  any 
thing  like  the  conversion  of  wood  into  this  coal-like  substance.  There  appears,  however, 
to  have  been  some  confusion  in  the  observations  of  those  who  have  written  on  the  subject. 
Mr.  Simpson,  the  intelligent  curator  of  the  Whitliy  museum,  who  has  paid  much  attention 
to  the  subject,  says: — "Jet  is  generally  considered  to  have  been  wood,  and  in  many  cases  it 
undoubtedly  has  been  so ;  for  the  woody  structure  often  remains,  and  it  is  not  unlikely  that 
comminuted  vegetable  matter  may  have  been  changed  into  jet.  But  it  is  evident  that  vege- 
table matter  is  not  an  essential  part  of  jet,  for  we  frequently  find  that  bone,  and  the  scales 
of  fishes  also  have  been  changed  into  jet.  In  the  Whitby  museum  there  is  a  large  mass  of 
bone,  which  has  the  exterior  converted  into  jet  for  about  a  quarter  of  an  inch  in  thickness. 
Tlie  jetty  matter  appears  to  have  first  entered  the  pores  of  the  bone,  and  there  to  have 
hardened  ;  and  during  the  mineralizing  process,  the  whole  bony  matter  has  been  gradually 
displaced,  and  its  place  occupied  by  jet,  so  as  to  preserve  its  original  form."  After  an 
attentive  examination  of  this  specimen,  we  are  not  disposed  to  agree  entirely  with  Mr. 
Simpson. 

Jet  certainly  incrusts  a  mass  which  has  something  the  structure  of  a  bone,  but,  without 
a  chemical  examination  of  its  constituents,  we  should  hesitate  even  to  say  it  was  bone. 
Wood  without  doubt  has  been  found  encrusted  with  jet,  as  fragments  of  animal  matter  may 
also  have  been.  But  it  is  quite  inconsistent  with  our  knowledge  of  physical  and  chemical 
changes,  to  suppose  that  both  animal  and  vegetable  matter  would  undergo  this  change.  By 
process  of  substitution,  we  know  that  silica  will  take  the  place  occupied  by  carbon,  or 
woody  matter ;  as,  for  example,  in  the  fossil  palms  of  Trinidad,  and  the  sihcified  forests  of 


KATTIMUXDOO  oe  CUTTEMUXDOO.  677 

Egypt ;  but  we  have  no  example  within  the  entire  range  of  the  coal  formations  of  the  world 
of  carbon  taking  the  place  of  any  of  the  earths. 

Jet  is  found  in  plates,  which  are  sometimes  penetrated  by  belemnites.  Mr.  Ripley,  of 
Whitby,  has  several  curious  examples :  two  plates  of  jet,  in  one  case  enclose  water-worn 
quartz  pebbles ;  and  in  another  jet  partially  invests  an  angular  fragment  of  quartz  rock. 
'*  This  is  the  more  remarkable,"  says  Mr.  Simpson,  "  as  quartz  rock,  or,  indeed,  any  other 
sort  of  rocky  fragment,  is  rarely  found  in  the  upper  lias." 

The  very  fact  that  we  find  jet  sun-ounding  belemnites,  casing  adventitious  masses  of 
stone,  and  investing  wood,  seems  to  show  that  a  liquid,  or  at  all  events  a  plastic  condition, 
must  at  one  time  have  prevailed.  We  have  existing  evidence  of  this.  Dr.  Young,  in  the 
work  already  quoted,  says : — "  In  the  cavities  of  nodules  containing  petrifactions,  we  some- 
times meet  with  petroleum,  or  mineral  oil.  When  first  exposed,  it  is  generally  quite  fluid, 
and  of  a  dark  green  color ;  but  it  soon  becomes  viscid  and  black,  and  at  last  hardens  into  a 
kind  of  pitch,  which  generally  melts  with  heat,  and  when  ignited  burns  with  a  crackling 
noise,  and  emits  a  strong  bituminous  smell."  One  more  sample  of  evidence  in  favor  of 
the  view  that  jet  has  been  formed  from  wood.  It  is  stated  (JReed's  Illustrated  Guide  to 
\M)itbi/)  that  in  front  of  the  cliflwork  of  Haiburne  Wyke  existed  a  petrified  stump  of  a 
tree,  in  an  erect  posture,  three  feet  high,  and  fifteen  inches  across,  having  the  roots  of  coaly 
jet  in  a  bed  of  shale ;  whilst  the  trunk  in  the  sandstone  was  partly  petrified,  and  partly  of 
decayed  sooty  wood.  Even  in  this  example  it  would  appear  that,  after  all,  a  coating  of  jet 
was  all  that  really  existed  upon  this  example  of  the  equisetum,  which  probably  stands  where 
it  grew.  Mr.  Simpson,  in  a  valuable  little  publication,  "  Tlie  Fossils  of  the  Yorkshire  Lias 
described  frora  Xature,icith  a  short  Outline  of  the  Geology  of  the  Yorkshire  Coast ,''' says : — 
"  From  all  we  know  respecting  this  beautiful  mineral,  it  appears  exceedingly  probable  that  it 
has  its  origin  in  a  certain  bituminous  matter,  or  petroleum,  which  abundantly  impregnates  the 
jet-rock ;  giving  out  a  strong  odor  when  it  is  exposed  to  the  air.  It  is  frequently  found  in  a 
liquid  state  in  the  chambers  of  ammonites  and  belemnites  and  other  cavities,  and,  whilst 
the  unsuspicious  operator  is  breaking  a  lias  nodule,  it  flies  out  and  stains  his  garment.  This 
petroleum,  or  mineral  oil,  also  occurs  in  nodules  which  contain  no  organic  remains ;  and  I 
have  been  informed  by  an  experienced  jet  miner  that  such  nodules  are  often  associated  with 
a  good  seam  of  jet,  and  are  therefore  regarded  as  an  omen  of  success." 

Jet  is  supposed  to  have  been  worked  in  this  country  long  before  the  time  of  the  Danes 
in  England,  for  the  Romans  certainly  used  jet  for  ornamental  purposes.  Lionel  Charlton, 
in  the  history  of  Whitby,  says  that  he  found  the  ear-ring  of  a  lady,  having  the  form  of  a 
heart,  with  a  hole  in  the  upper  end  for  suspension  from  the  ear;  it  was  found  in  one  of  the 
Roman  tumuli,  lying  close  to  the  jaw  bone.  There  exists  no  doubt  that  when  the  abbey  of 
Whitby  was  the  seat  of  learning  and  the  resort  of  pilgrims,  jet  rosaries  and  crosses  were 
common.  The  manufacture  was  carried  on  till  the  time  of  Elizabeth,  when  it  seems  to  have 
ceased  suddenly,  and  was  not  resumed  till  the  year  1800,  when  Robert  Jeflfei-son,  a  painter, 
and  John  Carter  made  beads  and  crosses  with  files  and  knives — a  neck -guard,  made  in  this 
manner,  fetched  one  guinea.  A  stranger  coming  to  Whitby  saw  them  working  in  this  rude 
way,  and  advised  them  to  try  to  turn  it ;  they  followed  his  advice  and  found  it  answer ; 
several  more  then  joined  them,  and  the  trade  has  been  gradually  increasing  since.  Most  of 
the  best  jet  ornaments  are  sent  to  London,  the  inferior  ones  are  mostly  purchased  for  the 
American  market. 

The  jet  workers  complain  of  the  great  scarcity  of  designs  in  jet.  Several  designs  have 
been  sent  them,  but  the  artists  not  being  acquainted  with  the  peculiarities  of  the  material, 
their  designs  are  not  generally  applicable,  and  the  manufacturer  is  much  more  successful 
in  the  imitation  of  natural  objects  than  any  artificial  combination. 


KALEIDOPFTOX.  An  instrument  devised  by  Prof.  Wheatstone.  An  elastic  thin  bar 
is  fixed  by  one  of  its  extremities,  and  at  its  free  end  it  carries  a  silvered  or  polished  ball ;  a 
ray  of  light  is  reflected  from  this  ball,  and  when  the  thin  plate  is  put  in  vibration,  the  fine 
point  of  light  describes  various  curves,  corresponding  with  the  musical  notes  produced  by 
the  vibrations. 

KAKX.  A  Cornish  miner's  term,  frequently,  according  to  Borlase,  used  to  signify  the 
solid  rock  ;  more  commonly  a  pile  of  rocks. 

KARSTEN'ITE.     The  name  given  bv  Haus  to  anhvdrous  suli)hate  of  lime. 

KATTIMUXDOO  or  CUTTEMUXDOO.  A  caoutchouc-like  substance  obtained  from  the 
Euphorbia  antiquorum  of  Roxburgh.  It  was  first  exhibited  in  this  country  in  the  Great 
Exhibition  of  1851,  being  sent  by  Mr.  W.  Elliott  from  Vizagapatam. 

It  was  of  a  dark  brown  color,  opaque  except  in  thin  pieces,  hard  and  somewhat  brittle 
at  common  temperatures,  but  easily  softened  by  heat.  Perfectly  insoluble  in  boiling  water, 
but  becoming  soft,  viscid,  and  remarkably  sticky  and  adhesive  like  bird-lime,  reassuming, 
as  it  cools,  its  original  character. 


678  KEG. 

KEG.     A  cask  containing  five  gallons. 

KEEVE,  a  milling  term.  A  large  vat  used  in  dressing  ores :  also  a  breiccr^s  term  for  a 
ma^sh  tub. 

KEIR.     A  boiler  used  in  I)leac'hing  establishments.     See  Bleaching. 

KNIFE-CLEANING  MACHINES.  Mr.  Kent's  machine  for  this  purpose  consists  of  a 
box  or  case,  containing  a  couple  of  wooden  discs,  fixed  near  to  each  other  upon  a  hori- 
zontal iron  rod  or  spindle,  which  passes  through  the  case,  and  is  caused  to  rotate  by  means 
of  a  winch-handle.  Each  disc  is,  for  about  three-fourths  of  the  area  of  its  inner  face,  cov- 
ered with  alternate  rows  of  bristles  and  strips  of  leather ;  and  the  remaining  fourth  part  is 
coveied  with  bristles  only.  The  knife-blades  to  be  cleaned  are  introduced  through  the 
openings  in  the  case,  between  the  rubbing  surfaces  of  the  discs ;  and  rotatory  motion 
being  given  to  the  discs  by  a  winch-handle,  the  knives  are  rapidly  cleaned  and  polished. 

Mr.  Masters  constiucted  knife-cleaning  machines  upon  the  same  plan  as  the  above  ;  but 
the  rubbing  surface  of  each  disc  is  formed  of  strips  of  buff  leather,  with  only  a  narrow 
circle  of  bristles  around  the  edge  of  each  surface,  to  clean  the  shoulders  of  the  knives ; 
small  brushes  are  fixed  beneath  the  holes  in  the  case,  through  which  the  blades  of  the 
knives  are  inserted,  to  prevent  the  exit  of  dust  from  the  apparatus. 

Mr.  Price  has  also  devised  a  machine  for  cleaning  knives,  and  another  for  cleaning  forks. 
The  knife-cleaner  consists  of  a  horizontal  drum,  covered  with  pieces  of  leather  or  felt,  and 
fixed  within  another  drum  or  circular  framing,  lined  with  leather  or  felt.  The  knives  are 
introduced  through  openings  in  a  movable  circular  yjlate,  at  the  front  of  the  outer  casing, 
and  enter  between  the  surfaces  of  the  two  drums.  The  jilatc  is  fixed  upon  a  horizontal  axis, 
which  extends  through  the  case,  and  is  furnished  at  the  back  with  a  handle  ;  by  turning 
which  the  disc  is  caused  to  rotate  and  carry  round  the  knives  between  the  surfaces  of  the 
drums.  The  fork-cleaner  consists  of  a  box,  with  a  long  rectangular  opening  in  the  side ; 
behind  which  two  biushes  are  fixed,  face  to  face.  Between  these  brushes  the  prongs  of  the 
forks  are  introduced,  and  the  handles  are  secured  in  a  carrier,  which  is  made  to  advance 
and  recede  alternately  by  means  of  a  throw-crank,  and  thereby  thrust  the  prongs  into 
and  draw  them  out  of  contact  with  the  brushes.  The  carrier  consists  of  two  metal  plates, 
the  lower  one  carrying  a  cushion  of  vulcanized  india-rubber  for  the  fork  handles  to  rest 
upon,  and  the  upper  being  lined  with  leather;  they  are  hinged  together  at  one  end,  and 
are  coiniected  at  the  other,  when  the  handles  have  been  placed  between  them,  by  a  thumb- 
screw. 

KUEOSOTE,  or  CREOSOTE.  One  of  the  many  singular  bodies  discovered  by  Reichen- 
l)ach  in  wood  tar.  It  derives  its  name  from  XP^°-^  ^^^  fci^cc,  I  preserve,  in  allusion  to  its 
remarkable  antiseptic  properties.  A  great  deal  of  confusion  exists  in  the  published  ac- 
counts of  wood  creosote,  owing  to  the  variable  nature  of  the  results  obtained  by  the 
chemists  who  have  examined  it.  This  confusion  is  not  found  with  that  from  coal,  which 
undoubtedly  contains  two  homologous  bodies,  C'-IFO^  and  C'^IFO" ;  the  first  being  car- 
bolic, and  the  second. cresylic  acid.  The  composition  of  carbolic  acid  has  long  been  known, 
owing  to  the  researches  of  Laurent:  cresylic  acid  was  recently  discovered  by  Williamson 
and  Fairlie.  Commercial  coal  creosote  sometimes  consists  almost  entirely  of  cresylic  acid. 
Coal  oils,  of  very  high  boiling  point,  contain  acids  ap])arently  homologues  of  carbolic  acid, 
higher  up  in  the  series  than  even  cresylic  acid,  and  yet  perfectly  soluble  in  potash. — {Gre- 
ville  Witliiiinx.)  There  is  little  douljt  that  wood  creosote  consists  essentially  of  the  same 
substances  as  that  from  coal.  The  great  difference  in  the  odor  arises  chiefly  from  the  fact 
of  the  product  from  coal  retaining  with  oljstinacy  traces  of  najihthaline,  parvoline,  and 
chinoline,  all  of  which  are  extremely  odorous.  No  creosote  found  in  commerce  is  ever 
perfectly  homogeneous,  nor,  in  fact,  is  it  necessary  that  it  should  be  so.  If  perfectly  solu- 
ble in  pota.sh  and  acetic  acid  of  the  density  ru70,  and  if  it  does  not  become  colored  by 
exposure  to  the  air,  it  may  be  consi<lered  pure  enough  for  all  medicinal  purposes.  The  oils 
from  wood  and  coal  tar  may  be  made  to  yield  creosote  by  the  following  process : — The  oils 
are  to  be  rectified  until  the  more  volatile  portions  (which  are  lighter  than  water)  have  passed 
over.  As  soon  as  the  product  running  fiom  the  still  sinks  in  water  the  receiver  is  to  be 
changed,  and  the  oils  maybe  received  until  the  teniiieraturc  required  to  send  over  the  oil  is 
as  high  as  480'  F.  The  oil  so  obtained  is  to  be  dissolved  in  caustic  soda,  all  insoluble  in  it 
being  rejected.  The  alkaline  solution,  after  being  mechanically  separated,  as  far  as  possi- 
ble, from  the  insoluble  oil,  is  to  be  boiled  for  a  very  short  time.  Two  advantages  are 
gained  by  this  operation: — any  volatile  bases  become  exiKlled,  and  a  substance  which  has  a 
tendency  to  become  Ijrown  on  keeping,  is  destroyed.  Sometimes  the  oil  on  treatment  with 
pota.sh  yields  a  ([uantity  of  a  crystalline  paste.  This  is  naphthaline,  and  should  be  removed 
by  filtration  through  coarse  calico  or  canvas.  The  alkaline  liquid  is  then  to  be  super- 
saturated with  dilute  suli)hnric  acid,  on  which  the  creosote  separates  and  rises  in  the  form 
of  an  oil  to  the  surface.  This  creo.sote  is  already  free  from  the  greater  number  of  impuri- 
ties, and,  if  rectified,  may  be  used  for  many  purposes.  To  obtain  a  purer  article  the  opera- 
tions commencing  with  solution  in  caustic  soda  are  to  be  repeated.  If  the  alkaline  solution 
on  boiling  again  becomes  colored,  the  purification  must  be  gone  through  a  third  time.     It 


LAMP-BLACK.  679 

is  essential  not  to  boil  the  alkaline  solution  long,  or  a  serious  loss  of  creosote  would  take 
place.  According  to  Reichenbach  the  boiling  point  of  creosote  is  39T\  Carbolic  acid 
boils  between  369^  and  370°.  Cresylic  acid  boils  at  397''.  From  this  it  would  appear  that 
Reichenbach's  creosote  consisted  of  cresylic  acid.  The  specific  gravity  of  creosote  accord- 
ing to  Reichenbach  is  r037  at  68°.  That  of  carbolic  acid  is  1"065  at  64'.  Carbolic  acid 
and  its  homologues,  when  mixed  with  quicklime  and  exposed  to  the  air,  yield  a  beautiful 
red  color,  owing  to  the  formation  of  rosohc  acid. — C.  G.  W. 


LACTIC  ACID,  C"H"0".  Spi.  Nanceic  acid.  {Acide  lactiqne,  Fr.  ;  Milchsaure, 
Germ.)  Discovered  by  Scheele  in  sour  milk.  Subsequently,  M.  Braconnot  examined  the 
sour  liquid  which  floats  above  starch  during  its  manufacture,  also  the  acidified  decoction  of 
various  vegetables,  including  beet-root,  carrots,  peas,  &c.,  and  found  an  acid  which  he 
considered  to  be  peculiar,  and  consequently  named  the  nanceic.  The  acid  formed  under  all 
these  circumstances  turns  out  to  be  the  same ;  it  is,  in  fact,  lactic  acid,  which  modern 
researches  show  to  be  a  constant  product  of  the  fermentation  of  sugar,  starch,  and  bodies 
of  that  class.  The  acidity  of  sauerkraut  is  due  to  the  presence  of  the  same  substance. 
Liebig  has  recently  extended  and  confirmed  the  experiments  made  many  years  ago  by 
Berzelius,  on  the  presence  of  lactic  acid  in  the  juice  of  flesh,  but  he  denies  its  existence  in 
urine,  as  asserted  by  MM.  Cap  and  Henry,  and  others. 

Lactic  acid  is  a  colorless  syrupy  liquid  of  a  powerful  pure  acid  taste.  Its  specific 
gravity  is  1-'213.  It  is  bibasic,  consequently  the  general  formula  for  the  lactates  is  C'-H" 
0"',2M0  ;  M  representing  any  metal. 

The  most  important  salts  of  lactic  acid  are  those  of  zinc  and  lime.  The  former  salt  is 
that  generally  formed  in  examining  animal  or  vegetable  fluids  with  a  view  to  the  isolation 
of  the  acid.  It  is  found  with  two  different  quantities  of  water,  according  to  the  circumstances 
under  which  it  is  prepar(^,  and  it  is  worthy  of  remark  that  the  amount  of  water  of 
crystallization  remarkably  affects  the  solubility  of  the  salt  in  water  and  alcohol. 

Lactic  acid  is  produced  from  alanine  by  the  action  of  nitrous  acid  according  to  the  fol- 
lowing equation : — 

2C«n'N0*  4-  2N0^  =  C'-II"0'-  +     V  +  2H0. 

Alanine.  Lactic  acid. 

Anhydrous  lactic  acid,  C'^H'^O'",  is  produced  by  the  action  of  heat  on  the  syrupy  acid. 
Lactic  acid  is  considered  by  chemists  to  be  constructed  on  the  type  of  four  atoms  of  water  in 

which  two  atoms  of  hydrogen  are  replaced  by  the  radical  lactyl,  thus : —      jxj       \  0*. 

The  other  two  atoms  of  hydrogen  are  consequently  basic.  It  has  been  said  that  lactic 
acid  may,  by  fermentation,  be  converted  into  butyric  acid ;  the  following  equation  represents 
the  metamorphosis: — 

C'^H'-O"  =  CIVO'  +  4C0''  +  4H. 

Lactic  acid.    Butyric  acid. 

All  the  butyric  acid  employed  for  the  preparation  of  butyric  ether,  orpine-apple  essence, 
is  now  prepared  bv  the  fermentation  of  lactate  of  lime. — C.  G.  W. 

LACUSTRINE  FORMATIOX  (a  geological  term).     Belonging  to  a  lake. 

LAMP-BLACK.  Every  person  knows  that  when  the  combustion  of  oil  in  a  lamp  is 
imperfect,  it  pours  forth  a  volume  of  dense  black  soot.  According  to  the  quantity  of  carbon 
contained  in  the  material  employed,  so  is  the  illuminating  power  of  the  flame  produced  by 
combustion.  If,  therefore,  we  have  a  very  brilliant  flame,  and  we  subject  it  to  any  con- 
ditions wliieh  shall  impede  the  progress  of  the  combination  of  the  carbon  with  the  oxygen 
of  the  air,  the  result  is  at  once  the  formation  of  solid  carbon,  or  lamp-black.  This  is 
exhibited  in  a  remarkable  and  often  an  annoying  manner  by  the  camphene  lamp.  If  oil  of 
turpentine,  resin,  pitch  oil,  or  fit  oil,  be  burnt  in  lamps  under  a  hood,  with  either  a  rapid 
draught  or  an  insufficient  supply  of  air,  the  lamp-black  collects  on  the  hood,  and  is 
occasionally  removed.  Sometimes  a  metallic  roller,  genei-ally  of  tin,  is  made  to  revolve  in 
the  flame,  and  rub  against  a  brush.  By  the  cooling  influence  of  the  metal,  the  heat  of 
the  flame  is  diminished,  the  combustion  retarded,  and  the  carbon  deposited,  and  in  the 
revolution  of  the  cylinder  swept  off".  Camphor  burning  forms  a  very  beautiful  black,  which 
is  sometimes  u.sed  as  a  pigment. 

The  common  varieties  of  lamp-black  are  made  from  all  sorts  of  refuse  resinous  matters, 
and  from  the  rejected  fragments  of  pine  trees,  &c.  In  Germany,  a  long  flue  is  constructed  in 
connection  with  the  furnace,  in  wliich  the  resinous  substances  are  liurnt,  and  this  (hie  com- 
municates with  a  hood,  composed  of  a  loose  woollen  cloth,  held  up  by  a  rope  passing  over 
a  pulley.     Upon  this  the  soot  collects,  and  is  from  time  to  time  shaken  down.     In  the  best 


680 


LAMPS. 


conducted  manufactories  about  3  cwt.  of  lamp-black  is  collected  in  each  hood  in  about  twelve 
hours.  In  England,  lamp-black  is  sometimes  prepared  from  the  refuse  coking  coal,  or  it 
is  obtained  in  connection  with  coke  ovens.  The  lamp-black,  however,  obtained  from  the 
combustion  of  coal  or  woody  matter  is  never  pure.     !see  Boxe  Black. 

LAMPS.  Lamps  a?re  very  varied  in  form,  and  equally  varied  in  the  principles  involved. 
A  brief  description,  however,  of  a  few  of  the  modern  varieties  must  suthce. 

The  moderator  lamp. — The  spiral  spring  has  recently  been  introduced  into  the  moderator 
lamps,  for  the  purpose  of  forcing  the  oil  up  the  wick  of  the  lamp.  This  will  be  understood 
by  the  following  description  and  drawings  : — Tiie  distinguishing  character  oi' the  moderator 
lamp  is  the  direct  trar.smi.ssion  of  the  power,  in  the  reservoir  of  oil,  to  the  resistance  ottered 
by  the  weight  of  the  column  of  oil,  as  it  rises  to  the  cotton  •, — and  secondly,  the  introduction 
of  a  rectangular  regulator,  which  equilibrates  constantly  by  the  resistance  of  the  oil  and  the 
force  applied  to  raise  it.  In  the  reservoir  (Jit/. 367)  is  a  spiral  spring  which  presses  on  the 
disc  or  piston,  {Ji(i.  3(58,)  which  is  furnished  with  a  valve  opening  downwards.  This  sjiring  is 
attached  to  a  tooth  rack,  worked  by  a  pinion  wheel,  by  the  means  of  which  it  is  wound  up. 
The  mechanical  force  of  the  spring  is  eijual  to  from  15  to  20  pounds;  and  as  this  fuice  is 
exerted  upon  the  disc,  floating  on  the  oil,  this  is  foiced  up  througli  the  tube,  and  it  over- 
flows to  the  argand  burner,  thoroughly  saturating  the  cotton,  and  supi)lying  a  constant 
stream  of  oil.  This  oil  falls  back  into  the  reservoir,  and  is,  of  course,  above  the  disc. 
When  the  spring  has  run  down,  it  is  again  wound  up ;  and  then  the  valve  opening  down- 
wards allows  the  oil  to  flow  back  beneath  the  disc,  to  be  again  forced  up  through  the  tube. 
As  the  pressure  employed  is  so  great,  the  oil  would,  but  for  the  "  modeiator,"  flow  with  too 
much  rapidity.  This  moderator,  or  regulator,  is  a  tapering  rod  of  iron-wire  which  is  placed 
in  the  ascending  tube;  and,  as  the  pressure  increases,  it  is  forced  more  into  it,  and  checks 
the  flow  of  oil ;  whereas,  as  it  diminishes  it  falls,  and  being  tapering,  allows  more  oil  to  rise. 
Several  ingenious  adjustments  are  introduced  into  these  lamps,  as  manufactured  by  the 
Messi-s.  Tylor  of  Warwick  Lane,  with  which  we  need  not  at  present  deal.  The  cylinders 
containing  the  oil  are  covered  with  cases  in  metal  or  sometimes  of  porcelain.  Two  drawings 
of  these  are  shown  {Jig.  369  sm&Jig.  370).    These  lamps  admit  evidently  of  yet  more  elegant 


3r.T 


303 


forms  than  have  been  given  them.     The  urn-shaped,  from  the  antique,  in  very  pure  taste, 
is  the  last  introduction  of  the  house  above  named. 

It  would  be  tedious  to  enumerate  the  various  modifications  of  form  and  action  to  which 
the  oil  lamp  has  been  sul)joct,  previous  to  its  arrival  at  what  may  be  deemed  its  perfect 
eonstruction  by  Argand.     The  discovery  of  the  mode  of  apj)lying  a  new  principle  by  this  in- 


LAMPS. 


681 


dividual  not  onlv  produced  an  entire  revolution  in  the  manufacture  of  the  article,  but 
threatened  with  ruin  all  those  whom  the  patent  excluded  from  participation  in  the  new  trade ; 
so  much  so,  indeed,  that  Argand,  who  had  not  been  apprenticed  to  the  business,  was  publicly 
persecuted  by  the  tinners,  locksmiths,  and  ironmongers,  who  disputed  his  right  by  any 
improvements  to  infringe  the  profits  of  their  chartered  vocation.  "This  invention,"  to 
quote  a  description  of  the  lamp  published  some  years  ago,  "  embraces  so  many  improve- 
ments upon  the  common  lamp,  and  has  become  so  general  throughout  Europe,  that  it  may 
be  justly  ranked  among  the  greatest  discoveries  of  the  age.  As  a  substitute  for  the  candle, 
it  has  the  advant;\ge  of  great  economy  and  convenience,  with  much  greater  brilliancy ;  and 
for  the  purpose  of  producing  heat,  it  is  an  important  instrument  in  the  hands  of  the  chemist. 
^S'e  may,  with  soaie  propnety,"  continues  this  authority,  "compare  the  common  lamp  and 
the  candle  to  fire  made  in  the  open  air,  without  any  forced  method  of  supplying  it  with 
oxygen ;  while  the  Argand  lamp  may  be  compared  to  a  tire  in  a  furnace,  in  which  a  rapid 
supplv  of  oxygen  is  furnished  by  the  velocity  of  the  ascending  current.  This,  however,  is 
not  the  onlv  advantage  of  this  valuable  invention.  It  is  obvious  that,  if  the  combustible 
vapor  occupies  a  considerable  area,  the  oxygen  of  the  atmosphere  cannot  combine  with  the 
vapor  in  thi  middle  part  of  the  ascending  column.  The  outside,  therefore,  is  the  only  part 
which  eaters  into  combustion ;  the  middle  constituting  smoke.  This  evil  is  obviated  in  the 
Argand  lamp,  by  directing  a  current  of  atmospheric  air  through  the  flame,  which,  instead 
of  being  raised  from  a  solid  wick,  is  produced  from  a  circular  one,  which  surrounds  the  tube 
tlu-ough  which  the  air  ascends.'' 

The  mechanism  of  the  Argand  burner,  in  its  present  improved  state,  will  be  clearly 
understood  from  the  annexed  figures  and  explanation, which  apply  equally  to  each  description 
of  the  lamps  hereafter  described. 

A  ( fig.  371 )  is  a  brass  tube,  about  3J  inches  in  length,  and  1^  inch  wide  ;  within  this  tube 
is  placed  another,  d,  which  is 
soldered    fast    inside   by  .the  — 

flange  at  c :  the  space  between 
thesj  tubes  contains  the  oil 
suriounding  the  wick,  and 
which,  being  freely  admitted 
from  the  reservoir  by  the  side 
pipes  D  E,  rises  in  the  tubu- 
lar space,  either  to  a  height 
corresponding  with  its  level 
in  the  reservoir,  or  at  least  so 
as  to  maintain  the  wick  in  a 
state  of  constant  saturation. 
The  tube  b  is  of  considerable 
thickness,  having  a  spiral  groove  cut  about  it  from  top  to  bottom :  f  is  a  metallic  ring  made 
to  slip  over  the  tube  b  ;  it  contains  a  short  pin  inside,  which  fits  exactly  into  the  spiral  groove 
just  mentioned :  g  is  the  circular  woven  cotton  wick,  the  lower  end  of  which  is  drawn  tight 
upon  the  neck  of  the  ring  :  h  is  a  copper  tube,  with  a  slit  nearly  from  top  to  bottom :  it 
admits  the  ring  r,  and  being  dropped  over  the  inner  tube  b,  exactly  fits  the  inside  of  the 
wider  tube  a,  by  means  of  a  narrow  rim  near  the  top  at  a,  and  another  at  the  bottom  b : 
between  the  upper  rim  and  the  margin,  there  is  a  small  projecting  pin  c,  whicli,  when 
the  whole  apparatus  is  combined,  fits  into  the  cavity  f,  of  the  collar  i.  To  prepare  the 
lamp  for  use,  the  tube  h  is  placed  between  a  and  b,  as  just  described ;  the  ring  f,  with 
its  charge  of  cotton,  is  next  inserted,  the  pin  in  the  inside  falling  into  the  spiral  groove, 
and  that  on  the  outside  entering  the  slit  in  the  tulie  h,  which,  on  being  turned  about,  moves 
the  ring  f  down  upon  the  screwed  inner  tube,  until  the  wick  only  just  rises  above  the  superior 
e  Iges  of  the  tubes,  in  the  interval  between  which  it  lies  in  the  oil.  ,  In  this  stage,  the  frame 
I  is  placed  on  the  nick  in  the  collar  at  c,  falling  upon  the  pin  near  the  top  of  ii :  the  lower 
d'licfg,  passing  over  the  tube  a,  at  once  presents  a  convenient  support  for  the  glass  chim- 
ney, and  a  finger-hold  for  raising  the  wick.  The  central  tulje  is  open  throughout,  com- 
municating, at  its  lower  end,  with  the  brass  receptacle  k  ;  the  latter  is  perforated  at  top,  to 
admit  the  air  which,  by  circulating  through  the  above  tube,  and  the  hollow  flame  which  sur- 
rounds it,  causes  the  lamp  to  burn  with  that  peculiar  freedom  and  brilliancy  which  dis- 
tinguish the  Argand  construction.  This  last-mentioned  receptacle  likewise  catches  any 
small  quantity  of  oil  which  may  pass  over  the  inner  tube  during  the  combustion  of  the 
wick.     L  is  the  brass  peg  which  fits  into  the  upper  part  of  the  pillar,  in  the  table  lamp. 

In  addition  to  the  endless  variety  of  small  portable  lamps,  the  peculiarities  of  which  it 
would  be  tedious  to  particularize,  and  the  merit  of  which,  as  compared  with  those  on  the 
Argand  principle,  consists,  for  the  most  part,  in  their  cheapness,  the  more  important 
articles,  atid  those  generally  in  demand,  may  be  distinguished  as  fixed  or  bracket  lamps, 
suspended  or  chandelier  lamps,  and  table  or  French  lamps  —  all  these  having  burners  on  the 
principle  above  described.     The  former  sort  were,  previous  to  the  introduction  of  gas,  very 


682 


LAMPS. 


common  in  shops.     The  globe  a,  {fig.  3*72,)  which  is  sometimes  made  plain  and  sometimes 
embossed,  as  in  the  cut,  screws  off  when  the  oil  is  poured  in  at  an  opening  in  the  lower  part 


3Y2 


373 


which  is  afterwards  closed  by  means  of  a  slide  attached  to  the 
stem  B,  and  the  globe,  thus  replenished,  is  inverted  and  screwed 
into  the  part  c.  When  the  lamp  is  used,  the  stem  b  is  raised  a 
little,  and  the  oil  is  suffered  to  flow  through  the  intermediate  tube 
into  the  cistern  d,  only  at  the  rate  at  which  it  is  consumed  by  the 
burning  of  the  wick.  The  peculiar  form  of  the  glass  chimney  e  . 
is  admirably  calculated  to  assist  in  the  more  complete  combustion 
of  the  matter  drawn  up  to  the  wick  when  impure  oil  is  used,  a 
desideratum  originally  in  part  secured  by  placing  over  the  cen- 
tral tube,  and  in  the  midst  of  the  flame,  a  circular  metal  plate, 
by  means  of  which  the  ascending  column  of  air  was  turned  out 
of  its  perpendicular  course,  and  thrown  immediately  into  that 
part  of  the  flame  where  the  smoke  is  formed,  and  which  by  this 
ingenious  contrivance  is  effectually  consumed ;  this  application, 
however,  is  not  necessary,  nor  the  form  of  much  moment,  when 
purified  sperm  oil  is  used.  These  lamps  being  usually  made  to 
move  on  a  pivot  at  f,  attached  to  the  wall  or  other  support,  are 
very  convenient  in  many  situations,  as  being  easily  advanced 
over  a  desk  or  counter,  and  afterwards  turned  aside  when  not  in 
use. 

The  sinumbral  lamp  having  passed  out  of  use  need  not  be 
described. 

The  use  of  spirit  lamps  followed,  and  we  have  the  naphtha 
and  camphene  lamps  of  this  order.  The  accompanying  woodcut 
{firi-  373)  .shows  the  peculiarity  of  the  camphene  lamp  where  the 
reservoir  of  spirit  (turpentine  deprived  of  smell)  is  far  below  the  burner,  to  which  it  ascends 
by  capillary  attraction,  tlu'ough  the  tubes  of  the  cotton  wick.  Lamps  to  burn  naphthas 
{Belmontiiie,  &c.)  are  constructed  on  the  same  princii)le. 

One  of  the  best  oil  lamp  is  that  known  as  Carcel's  lamp. 

In  this  lamp  the  oil  is  raised  through  tubes  by  clock-work,  so  as  continually  to  overflow 
at  the  bottom  of  the  burning  wick ;  thus  keeping  it  thoroughly  soaked,  while  the  excess  of 
the  oil  drops  back  into  the  cistern  below.  I  have  possessed  for  several  years  an  excellent 
lamp  of  this  description,  which  performs  most  satisfactoi  ily ;  but  it  can  hardly  be  trusted  in 
the  hands  of  a  servant ;  and  when  it  gets  at  all  deranged,  it  must  be  sent  to  its  constructor 
in  Paris  to  be  repaired.  The  light  of  this  lamp,  when  furni.--licd  with  an  appropriate  tall 
gla.ss  chimney,  is  very  brilliant,  though  not  perfectly  uniform  ;  since  it  fluctuates  a  little,  but 
always  perceptibly  to  a  nice  observer,  with  the  alternating  action  of  the  pump-work ;  be- 
coming dimmer  after  every  successive  jet  of  oil,  and  Inighter  just  before  its  return.  The 
flame,  moreover,  always  flickers  more  or  less,  owing  to  the  powerful  draught,  and  rectangular 
reverberatory  shoulder  of  the  chimney.  The  mechanical  lamp  is,  however,  remarkable  for 
continuing  to  burn,  not  only  with  unabated  but  with  increasing  splendor  for  seven  or  eight 
hours ;  the  vivacity  of  the  combustion  increasing  evidently  with  the  increased  temperature  and 
fluency  of  the  oil,  which  by  its  ceaseless  circulation  tlnough  the  ignited  wick,  gets  eventually 
pretty  warm.  In  the  comparative  experiments  made  upon  different  lights  by  the  Parisian 
philosophers,  the  mechanical  lamp  is  commonly  taken  as  the  standard.  I  do  not  think  it 
entitled  to  this  preeminence :  for  it  may  be  made  to  emit  very  different  quantities  of  light, 


LEAD.  683 

according  to  differences  in  the  nature  and  supply  of  the  oil,  as  well  as  variations  in  the 
form  and  position  of  the  chimney.  Besides,  such  lamps  are  too  rare  in  this  country  to  be 
selected  as  standards  of  illumination. 

LAMPIC  ACID.  Si/ti.  Aldehydic  acid;  Acetylous  acid.  {Acide  Lampigue,  Tr.)  If 
a  little  ether  be  placed  at  the  bottom  of  a  glass,  and  some  spongy  platinum  attached  to  a 
wire  of  the  same  metal  be  ignited  and  suspended  about  an  inch  from  the  fluid,  it  will  glow 
and  continue  to  do  so  for  a  long  time.  On  the  other  hand,  if  a  spiral  of  platinum  wire  be 
placed  over  the  wick  of  a  spirit  lamp,  and  the  latter  be  first  ignited  and  then  blown  out,  the 
wire  will  continue  at  a  red  heat  until  all  the  spirit  is  exhausted.  Numerous  sesquioxides, 
when  placed  warm  on  wire  gauze  over  capsules  containing  alcohol,  will  glow  in  the  same 
manner.  Under  all  these  circumstauces,  a  powerful  odor  resembling  aldehyde  is  evolved, 
which  strongly  affects  the  eyes.  If  this  experiment  be  made  in  such  a  manner  that  the 
volatile  product  may  be  condensed,  it  will  be  found  to  be  strongly  acid.  It  is  powerfully 
rjducing  in  its  tendency,  and  if  heated  with  the  oxides  of  silver  or  gold,  converts  them  into 
the  metallic  state,  and  the  liquid  is  found  to  contain  acetic  acid  and  resin  of  aldehvde.  If, 
however,  the  acid  liquid  be  only  very  gently  warmed  with  oxide  of  silver,  a  portion  of  the 
latter  is  dissolved ;  but  when  baryta  is  added  to  precipitate  the  silver  as  oxide,  and  the  fluid 
is  warmed,  the  metal  instead  of  the  oxide  comes  down,  and  the  fluid  when  tested  for  the 
nature  of  the  acid,  is  found  to  contain  nothing  but  acetate  of  baryta.  These  phenomena 
a.e  explained  by  some  chemists  by  supposing  the  fluid  to  contain  an  acid  which  they,  fol- 
lowing the  late  Professor  Daniell,  call  the  lampic,  and  supposed  to  contain  C^H^O^  When 
lampic  acid  is  treated  first  with  oxide  of  silver  and  then  with  baryta  water,  and  heated,  tliey 
consider  that  the  oxygen  of  the  oxide  of  silver  is  transferred  to  the  lampic  acid,  converting 
it  into  acetic  acid,  which  combines  with  the  baryta,  while  the  metallic  silver  is  precipitated. 
The  following  equation  explains  the  reaction  supposed  to  take  place : — 
C^H^O'  +  BaO  +AgO  =  C^II'O^BaO  +  Ag  -^  HO. 

Lampic  acid.  Acetate  of  baryta. 

The  conversion  of  the  lampic  into  acetic  acid  is  therefore  attributed  to  the  oxidizing  ten- 
dency of  the  oxide  of  silver.  Those  who  regard  the  decomposition  from  the  above  point  of 
view  consider  lampic  acid  to  be  acetylous  acid,  that  is  to  say,  to  bear  the  same  relation  to 
acetylic  acid  (acetic  acid)  that  sulphurous  acid  does  to  sulphuric  acid. 

The  above  explanation,  although  simple,  does  not  really  render  a  satisfactory  accoimt 
of  the  reactions  which  bear  upon  the  subject.  Aldehyde,  when  treated  with  oxide  of  silver, 
does,  it  is  true,  become  converted  into  the  same,  or  apparently  the  same,  substance  as 
lampic  acid,  but  the  probabiHties  are  in  favor  of  Gerhardt's  supposition,  that  the  lampates 
are  in  fact  aldehyde,  in  which  an  equivalent  of  hydrogen  is  replaced  by  a  metal.  That  the 
aldehydes  are  capable  of  uniting  with  metals  with  elimination  of  hydrogen  has  been,  on 
more  than  one  occasion,  proved  by  experiment.  There  is  great  difficulty  in  preparing  the 
sodium  aldehyde  of  the  vinic  series,  but  the  author  of  this  article  has  found  that  if  euodic 
aldehyde  from  oil  of  rue  be  treated  with  sodium,  a  definite  compound  is  formed,  having 

the  formula  t>-    f- . 

^a  S 

If,  therefore,  we  admit  aldehyde  to  be  formed  on  the  hydrogen  type,  that  is  to  say,  two 

atoms  of  hydrogen  in  which  one  is  replaced  bv  the  oxidized  radical  acetvl,  we  shall  have  for 

aldehyde,  rr  [ ;  and  for  the  lampates,  acetylurets,  or  aldehydates,  mi*     ^'  ^^''' 

hardt,  who  views  the  lampates  in  the  above  light,  regards  aldehyde  as  the  true  acetylous 
acid.     See  Acetyl. — C.  G.  W. 

LAPS.  Metal  polLshing  wheels.  Metal  wheels  or  laps  made  of  nearly  every  metal  and 
alloy  in  common  use,  have  been  more  or  less  employed  in  the  mechanical  arts  as  vehicles 
for  the  application  of  several  of  the  polishing  powders.  But  of  all  laps,  notwithstanding 
their  variety,  those  of  lead,  slightly  alloyed,  and  supplied  with  powdcrecl  emery,  render  the 
most  conspicuous  service.  Generally  the  plane,  or  flat  surface  of  the  lap,  is  employed ;  at 
other  times  the  cylindrical  edge,  as  by  cutlers;  but  the  portion  actually  used  is  in  either 
case  called  the  face  of  the  lap.  There  are  several  kinds  of  laps.  The  lap  is  in  some  cases 
a  thin  disc  of  metal,  fixed  l)y  means  of  a  screwed  nut  against  a  shoulder  on  the  spindle,  but 
it  is  better  with  lead  laps  to  employ  an  iron  plate  cast  full  of  holes,  to  support  the  softer 
metal.  The  casting  mimld  may  in  this  case  be  either  an  iron  disc,  with  a  central  screw  to 
fix  the  iron  centre  plate  at  the  time  of  pouring,  or  the  mould  maybe  made  of  sand,  and  in 
halves,  after  the  usual  manner  of  the  foundry.  In  either  case  the  iron  plate  should  be  made 
as  hot  as  the  fluid  metal,  which,  by  ent(>ring  the  holes,  becomes  firndy  united  to  the  iion, 
especially  if  the  holes  are  largest  on  the  reverse  side,  or  that  away  from  the  lead. — Jlolt- 
zapffel. 

Lap  is  also  a  roll  or  sliver  of  cotton  for  feeding  the  cards  of  a  spinning  machine. 

LEAD.  Although  lead  foruis  an  essential  element  in  a  large  number  of  minerals,  the 
ores  of  this  metal  are,  strictly  speaking,  far  from  numerous.     Of  these  the  most  important 


684  LEAD. 

is  sulphide  of  lead,  or  galena.  This  mineral,  which  possesses  a  metallic  brilliancy,  and  has 
a  lighter  color  than  metallic  lead,  presents,  in  its  cleavage,  all  the  variations  from  large 
facettes  and  lamin;c  indicating  a  cubic  crystallization  to  a  most  minutely  granular  structure. 
It  is  extremely  brittle,  and  its  powder  presents  a  brilliant  blackish-gray  appearance. 

The  specific  gravity  of  galena  is  7'5  to  IS,  and  its  composition,  when  absolutely  pure, 
is: — 

Lead 86-55 

Sulphur 13-45 


100-00 

Galena  is,  however,  but  seldom  found  chemically  pure,  as,  in  addition  to  variable  quan- 
tities of  earthy  imi)urities,  it  almost  always  contains  a  certain  amount  of  silver.  It  is  usually 
observed  that  galena  presenting  large  facettes  is  less  argentiferous  than  those  varieties  hav- 
ing a  closer  grain,  and  that  finely  granular  steely  specimens  generally  afford  the  largest 
amount.of  silver. 

It  would  appear,  from  recent  experiments,  that  the  silver  contained  in  the  finely-granu- 
lar varieties  of  galena  often  occurs  in  the  form  of  sulphide  of  silver,  mechanically  inter- 
mixed, whilst  in  the  more  flaky  descriptions  of  this  ore,  the  sulphides  of  lead  and  silver  are 
chemically  combined. 

Galena  occurs  in  beds  and  veins,  in  granite,  gneiss,  day-slate,  limestone,  and  sandstone 
rocks. 

In  Spain  it  is  found  in  the  granite  hills  of  Lanaies  and  elsewhere  ;  at  Freiberg  in  Saxony 
it  occupies  veins  in  gneiss;  in  the  Ilarz,  Bohemia,  Cornwall,  and  many  other  localities,  it  is 
found  in  killas,  or  clay-slate.  The  rich  deposits  of  Derbyshire,  Cumberland,  and  the  north- 
ern di>tricts  of  England,  are  in  the  mountain  limestone,  whilst  at  Commcrn,  near  Aix-la- 
Chaj)olle,  large  ciuuntities  of  this  ore  are  found  disiseminatcd  in  the  Bunter  sandstone. 

This  mineral  is  frequently  associated  with  blende,  iron  and  copper  pyrites,  the  carbonate 
and  other  ores  of  lead,  and  usually  occurs  in  a  gangiie  of  sulphate  of  baryta,  calcspar,  spa- 
fhose  iron,  or  quartz.     It  is  also  not  unfrequently  associated  with  fluorspar. 

The  next  most  important  ore  of  lead  is  the  carbonate,  which  is  a  brittle  mineral,  of  a 
white  or  grayish-white  color,  having  a  specific  gravity  varying  from  6-46  to  6-50.  Its  com- 
position is: — 

Carbonic  acid 16-05 

Oxide  of  lead 83-56 

99-61 
Large  quantities  of  this  substance  occur  in  the  mines  of  the  Mississippi  Valley  in  the 
United  States  of  America,  where  they  were  formerly  thrown  away  as  useless,  but  have  since 
been  collected  and  smelted.  Vast  deposits  of  this  su1)stance  have  also  been  found  in  the 
Bunter  sandstone,  near  Duren,  in  Prussia,  and  at  P'rcyung,  in  Bavaria.  In  the  two  latter 
localities  it  appears  to  form  the  cement  holding  together  the  granules  of  quartz,  of  which 
the  sandstone  principally  consists.  These  ores,  which  yield  from  14  to  20  per  cent,  of 
metal,  do  not  readily  admit  of  being  concentrated  by  wa.shing. 

The  sulphate  of  lead  does  not  often  occur  in  sufficient  (juantities  to  be  employed  as  an 
ore  of  that  metal.     In  appearance  it  is  not  unlike  the  carbonate,  but  may  readily  be  distin- 
guished from  it  by  its  not  dissolving  with  effervescence  in  nitric  acid. 
Its  specific  gravity  is  from  6-25  to  6-30,  and  its  composition: — 

Sulphuric  acid 25-65 

Oxide  of  lead 74-05 

99-70 

This  ore  of  lead  usually  results  from  the  oxidation  of  galena.  At  St.  Martin's,  near  the 
Vega  de  Ribaddeo,  in  Spain,  this  mineral,  more  or  less  mixed  with  the  phosphate  of  lead, 
is  foimd  in  suflficient  quantities  to  be  made,  on  a  small  scale,  the  subject  of  an  especial 
metallurgic  treatment.  Large  f|uantities  of  sulphate  of  lead  ores  are  also  annually  in)i)()rtcd 
into  this  country  from  the  mines  in  Australia.  These  ores  contain  on  an  average  35  per 
cent,  of  lead,  and  35  oz.  of  silver  to  the  ton  of  ore,  together  with  a  little  gold. 

Phosphate  of  lead,  when  crystallized,  usually  piesents  the  appearance  of  hexagonal 
prisms,  of  a  bright-green,  brown,  or  yellowish  color.  Its  specific  gravity  varies  from  6-5  to 
7'1.  This  mineral  is  composed  of  a  mixture  of  true  phosphate  of  lead,  phosphate  of  lime, 
chloride  of  lead,  and  fluoride  of  calcium,  and  usually  contains  about  78  per  cent,  of  oxide 
of  lead.  In  Spain,  it  occurs  in  botryoijJal  forms,  in  connection  with  the  sulphate  of  the 
same  metal,  and  is  treated  in  bla.st  furnaces  for  the  lead  it  affords. 

The  other  minerals  containing  lead  seldom  occur  in  sufficient  quantities  to  be  of  mtich 
impf)rtance  to  the  smelter,  and  may  therefore  be  disregarded  in  the  present  article. 

The  extraction  and  mechanical  preparation  of  ores  is  the  business  of  the  miner,  and  not 


LEAD.  685 

of  the  metallurgist,  who  receives  them  from  the  former  freed  as  perfectly  as  possible  from 
foreign  matters. 

The  metallurgic  processes  by  the  aid  of  which  lead  is  obtained  from  galena,  may  be 
divided  into  two  classes.  The  fii-st  of  these  is  founded  on  the  following  reactions: — If  one 
equivalent  of  sulphide  of  lead  and  two  equivalents  of  the  oxide  of  the  same  metal  are  fused 
together,  the  result  is  three  equivalents  of  metallic  lead  and  one  equivalent  of  sulphurous 
acid,  which  is  evolved. 

This  reaction  is  represented  by  the  following  equation: — 
PbS  +  2FbO  =  3Pb  +  SO'. 

When,  on  the  other  hand,  one  equivalent  of  sulphide  of  lead  and  one  equivalent  of  sul- 
phate of  lead  are  similarly  treated,  two  equivalents  of  lead  are  obtained,  and  two  equivalents 
of  sulphurous  acid  gad  evolved.     Thus  : — 

PbS  +  PbO,SO'  =  2Pb  +  2S0'. 

The  process,  founded  on  the  foregoing  reactions,  and  which  we  will  distinguish  as  the 
method  b>/  double  decomposition,  consists  in  roasting  the  galena  in  a  reverberatory  furnace 
until  a  certain  amount  of  oxide  and  sulphate  has  been  formed,  and  subsequently,  al'ter  hav- 
ing intimately  mixed  the  charge  and  closed  the  doors  of  the  furnace,  causing  the  whole  to 
enter  into  a  state  of  fusion. 

During  this  second  stage  of  the  operation,  the  reaction  between  the  sulphides,  sulphates, 
and  oxides  takes  place,  and  metallic  lead  is  eliminated.  The  roasting  of  the  ore  is,  in  some 
cases,  conducted  in  the  same  furnace  in  which  the  fusion  is  effected,  whilst  in  others  two 
separate  furnaces  are  employed. 

The  process  by  double  decomposition  is  best  adapted  for  the  richer  varieties  of  ore,  and 
such  as  are  least  contaminated  by  silieious  or  earthy  impurities,  and  is  consequently  that 
which  is  almost  universally  employed  for  smelting  the  ores  of  this  country. 

By  the  second  method,  which  we  will  call  the  process  b>/  affinity,  the  ore  is  fused  with  a 
mixture  of  metallic  iron,  which,  by  combining  with  the  sulphur,  liberates  the  metallic  lead. 
This  reaction  will  be  understood  by  reference  to  the  following  formula : — 
PbS  -f  Fe  =  Pb  H-  FeS. 

In  practice,  however,  metallic  iron  is  not  always  employed  for  this  purpose ;  cast  iron  is 
also  frequently  used,  and  in  some  instances  the  ores  of  iron  and  hammer  slags  are  substi- 
tuted, as  are  also  tap-cinder  and  other  secondary  products  containing  a  considerable  per- 
centage of  this  metal.  None  of  these  substances  are,  however,  found  to  be  so  efScacious  as 
metallic  iron,  since  cast  iron  requires  to  be  decarburized  before  it  can  readily  decompose 
the  sulphide  of  lead,  and  the  ores  of  iron  require  the  introduction  of  various  fluxes,  and  the 
consequent  expenditure  of  an  additional  amount  of  fuel.  In  all  cases,  however,  it  is  judi- 
cious to  subject  the  ore  to  a  preliminary  roasting,  in  order  to  eliminate  a  portion  of  the  sul- 
phur, and  thereby  reduce  the  expenditure  of  iron,  as  well  as  to  agglutinate  the  ore  and 
render  it  better  adapted  for  its  subsequent  treatment  in  the  blast  furnace. 

We  will  not  attempt  to  describe  the  different  forms  given  to  roasting  furnaces  emploved 
for  the  ores  treated  by  this  process,  but  would  remark  tliat  they  frequently  resemble  the 
kilns  used  for  the  preparation  of  lime,  whilst  in  some  instances  the  ores  are  roasted  in  heaps 
interstratified  with  wood  or  other  fuel. 

The  method  of  treating  ore  by  afpnity  is  particularly  adapted  to  those  varieties  that 
contain  a  considerable  amount  of  silica,  since  such  minerals,  if  treated  by  double  decompo- 
sition, would,  by  the  formation  of  oxide  of  lead,  give  rise  to  silicates,  from  which  it  would 
be  exceedingly  diflScult  to  extract  the  metal. 

English  process.  Treatment  by  double  decomposition. — Galena,  if  placed  in  a  close  ves- 
sel which  protects  it  from  the  action  of  the  air,  and  exposed  to  a  gradually  increasing  tem- 
perature, becomes  fused  without  the  elimination  of  any  lead  taking  place,  but  ultimately  a 
portion  of  the  sul])hur  is  driven  off,  and  a  subsulphide  is  formed,  which  at  a  very  elevated 
temperature  is  volatilized  without  change. 

If,  however,  the  vessel  be  uncovered,  and  the  air  allowed  to  act  on  its  contents,  oxygen 
combines  with  the  sulphur,  sulphurous  acid  is  evolved,  and  the  desulphuration  of  the  min- 
eral is  slowly  effected. 

When  galena  is  spread  on  the  hearth  of  a  reverberatory  furnace,  and  is  so  placed  as  to 
present  the  largest  possible  amount  of  surface  to  oxidizing  influences,  it  will  be  found  that 
the  surface  slowly  becomes  covered  with  a  yellowish-white  crust  of  suljihate  of  lead.  The 
oxygen  of  the  air,  by  combining  with  the  two  c'ementary  bodies  of  which  galena  is  com- 
posed, will  evidently  produce  this  eflect.  This  is  not,  however,  the  only  chemicid  change 
which  takes  place  in  the  charge  under  these  circumstances :  oxide  of  lead  is  producetl  at 
the  same  time  as  the  sulphate,  or  rather  the  formation  of  the  oxide  is  prior  to  that  of  the 
sulphate. 

In  fact,  during  the  first  stage  of  the  operation  of  roasting  suljihurous  acid  is  evolved, 
the  sulphur  quits  the  lead,  and  a  portion  of  that  metal  remains  in  a  free  state.  This  be- 
comes oxidized  by  the  air  passing  through  the  furnace,  and  subsequently  a  part  of  it  com- 


686 


LEAD. 


bines  with  sulphuric  acid,  formed  by  the  oxidation  of  sulphurous  acid,  and  sulphate  of  lead 
is  the  result.  In  this  way,  after  the  expiration  of  a  certain  period,  both  oxide  and  sulphate 
of  lead  are  present  in  the  furnace.  . 

During  the  early  period  of  the  roasting,  when  the  temperature  of  the  furnace  is  not 
very  elevated,  the  proportion  of  sulphate  is  larger  than  that  of  the  oxide  formed,  but  in 
proportion  as  the  heat  of  the  apparatus  increases,  the  production  of  oxide  becomes  more 
considerable,  whilst  that  of  the  sulphate  diminishes. 

The  sulphate  and  oxide  thus  formed  re-act  in  their  turn  on  the  undecomposed  galena, 
whilst  a  portion  of  the  latter,  by  combining  with  the  sulphide  of  lead,  gives  rise  to  the 
formation  of  oxysulphidc. 

This  last  compound  has  no  action  on  galena,  except  to  dissolve  it  in  certain  propor- 
tions, but  is  readily  decomposed  by  the  aid  of  carbonaceous  matter. 

It  is  therefore  evident  that  the  addition  of  carbon,  at  this  stage  of  the  operation, 
will  have  the  effect  of  reducing  the  oxide  and  oxysiilphide  of  lead. 

Every  process  then  that  has  for  its  object  the  reduction  of  lead  ores  by  double  de- 
composition, comprises  two  principal  operations: — 1st.  The  reduction  of  galena,  by  the 
aid  of  heat  and  atmospheric  air,  to  a  mixture  of  sulphide,  oxide,  and  sulphate,  which 
mutually  decompose  each  other,  with  the  elimination  of  metallic  lead.  2d.  The  re- 
duction of  the  oxysulpliide  by  the  addition  of  carbonaceous  matter. 

The  rcvcrberatori/  furnace. — The  revcrberatory  furnace  employed  for  the  treatment  of 
galena  is  conii)oscd,  like  all  other  furnaces  of  this  description,  of  three  distinct  parts, 
the  fire-place,  the  hearth,  and  the  chimney. 

The  hearth  has  to  a  certain  extent  the  form  of  a  funnel,  of  which  the  lowest  point  is 
on  the  front  side  of  the  furnace  immediately  below  the  middle  door.  The  molten  metal 
descending  from  every  side  along  the  inclined  bot-tom  or  sole,  is  collected  in  this  recep- 
tacle, and  is  ultimately  run  off  by  means  of  a  proper  tap-hole.  This  tap-hole  is,  during 
the  operation,  closed  by  a  pellet  of  clay. 

The  inclination  of  the  hearth  is  more  rapid  in  the  vicinity  of  the  fire-bridge  than  to- 
wards the  chimney,  in  order  that  the  liquid  metal  may  not  be  too  long  exposed  to  the 
oxidizing  and  volatilizing  influences  of  a  current  of  strongly-heated  air. 

The  dimen.sions  given  to  these  furnaces,  as  well  as  the  weight  of  the  charge  operated 
on  at  one  time,  vary  considerably  in  different  localities,  but  in  the  north  of  England  the 
following  measurements  are  usually  employed  : — The  fire-grate  is  5  ft.  9  in.  x  1  ft.  10  in., 
and  the  thickness  of  the  fire-bridge  1  ft.  6  in. ;  the  length  of  the  sole  is  9  ft.,  and  its  av- 
erage width  7  ft.  The  depth  of  the  tap  is  about  2  ft.  6  in.  below  the  top  of  the  inclined 
sole.  The  height  of  the  roof  at  the  fire-end  may  be  1  ft.  4  in.,  and  at  the  other  extrem- 
ity 11  inches. 

The  introduction  of  the  charge  is  in  some  cases  effected  by  the  doors  of  the  furnace, 
whilst  in  other  instances  a  hopper,  placed  over  the  centre  of  the  arch,  is  made  use  of. 

On  the  two  sides  of  the  furnace  are  placed  throe  doors  about  11  in.  x  9  in.,  which 
are  distinguished  as  1,  2,  and  3,  counting  from  the  fire-bridge  end.  The  three  doors  on 
the  one  side  are  known  as  the  front  doors,  whilst  those  on  the  other  side  are  called  the 
back  doors.  Immediately  beneath  the  door  on  the  front  side  of  the  furnace  is  situated 
the  iron  pan  into  which  the  molten  lead  is  tapped  off. 

The  bottom  of  this  arrangement  is  in  most  cases  composed  of  fire-bricks,  covered  by 
a  layer  of  vitrified  slags,  of  greater  or  less  thickness.  In  order  to  form  this  bottom,  the 
slags  are  introduced  into  the  furnace,  the  doors  closed,  and  the  damper  raised.  An 
elevated  temperature  is  thus  quickly  obtained,  and  as  soon  as  the  scoriaj  have  become 
sufficiently  fused,  they  are,  by  means  of  rakes  and  paddles,  made  to  assume  the  rccjuired 
form.  The  charge  cm])Ioyed,  as  before  stated,  varies  in  almost  every  establishment.  In 
the  north,  however,  smaller  charges  are  used  than  in  n;ost  other  localities.  At  New- 
castle, and  in  the  neighborhood,  the  charge  varies  from  12  to  14  cwt. ;  in  Wales,  and 
near  Bristol,  21  cwt.  charges  are  treated;  whilst  in  Cornwall,  charges  of  30  cwt.  are  not 
unfrcquently  worked.  The  time  required  for  smelting  a  charge  varies  «ith  its  weight 
and  the  nature  of  the  ores,  from  6  to  24  hours. 

In  some  cases  the  ore  is  introduced  raw  into  the  furnace,  whilst  in  others  it  under- 
goes a  preliminary  roasting  previous  to  its  introduction.  Rich  ores  are  generally  smelted 
without  being  first  calcined,  but  the  poorer  varieties,  and  particularly  those  which  con- 
tnin  large  quantities  of  iron  pyrites,  are,  in  most  instances,  subjected  to  roasting  in  a  sep- 
arate furnace. 

In  order  to  understand  more  clearly  the  operation  of  smelting  in  furnaces  of  this 
description,  we  will  suppose  that  a  charge  has  just  been  tapped  off,  and  that,  after 
tlioroiighly  clearing  the  hearth,  a  fresh  charge  of  raw  ores  has  been  introduced.  During 
the  first  part  of  the  operation  of  roasting,  which  usually  occupies  about  two  hours,  the 
doors  arc  taken  ofi'  to  admit  free  access  of  air,  and  also  for  the  purpose  of  cooling  the 
furnace,  which  has  been  strongly  heated  at  the  close  of  the  preceding  operation.  No 
fuel  is  at  this  period  charged  upon  the  grate,  since  the  heat  of  the  furnace  is  of  itself  suf- 


LEAD. 


687 


ficient  to  effect  the  elimination  of  the  first  portions  of  sulphur.  The  ore  is  carefully 
stin-ed,  for  the  purpose  of  constantly  presenting  a  fresh  surface  to  oxidizing  influences, 
and  when  white  fumes  are  no  longer  observed  to  pass  off  in  large  quantities,  a  little  coal 
may  be  thrown  on  the  grate,  and  the  temperature  gradually  elevated  until  the  charge  be- 
comes slightly  clammy  and  adheres  to  the  rake.  When  the  roasting  is  considered  as 
being  sufficiently  advanced,  the  smelter  turns  his  attention  to  the  state  of  the  fire,"  taking 
care  to  remove  the  clinkers  and  get  the  grate  into  proper  condition  for  the  reception  of 
a  fresh  supply  of  fuel.  The  furnace  doors  are  now  closed,  and  a  strong  heat  is  kept  up 
for  about  a  quarter  of  an  hour,  when  the  smelter  examines  the  condition  of  his  charge 
by  remoTing  one  of  the  doors.  If  the  operation  is  progressing  satisfactorily,  and  the 
lead  flowing  fre^'ly  and  passing  without  obstruction  into  the  tap,  the  firing  is  continued  a 
little  longer;  bat  when  the  ores  have  been  found  to  have  taken  fire,  or  are  lying  uneven- 
ly on  the"botto;n  of  the  furnace,  the  position  of  the  charge  is  changed  by  the  use  of  an 
iron  paddle.  During  this  operation  the  furnace  becomes  partially  cooled,  and  the  re- 
duction of  temperature  thus  obtained  is  frequently  found  to  produce  decompositions, 
which  facilitate  the  reduction  of  the  charge.  In  the  case  of  extremely  refractory  ores 
this  alternate  heating  and  cooling  of  the  furnace  is  sometimes  almost  indispensable,  whilst, 
in  other  instances,  their  being  once  or  twice  raked  over  is  all  the  manipulation  that  is 
required. 

We  will  suppose  that  four  hours  have  now  elapsed  since  the  charging  of  the  furnace, 
and  that  the  charge  has  run  down  tlie  inclined  sole  towards  the  tap.  The  smelter  now 
examines  the  condition  of  the  scoria  and  adds  a  CQuple  of  shovelfuls  of  hme  and  three 
or  four  shovelfuls  of  small  coals,  the  amount  and  relative  proportions  of  these  being  reg- 
ulated in  accordance  with  the  aspect  of  the  slags.  The  charge  is  now,  by  means  of 
proper  tools,  again  raised  to  the  breast  of  the  furnace,  and  the  firing  continued  until  the 
charge  has  run  down  into  the  tap-hole.  The  foreman  now  takes  his  rake  and  feels  if 
any  lumps  remain  in  an  unfused  condition,  and  if  he  finds  all  to  be  in  a  fluid  state  he  calls 
his  assistant  from  the  other  side,  and  by  the  addition  of  a  small  quantity  of  lime  and  fine 
coal,  makes  the  slag  assume  a  pasty  or  rather  doughy  consistency.  By  the  aid  of  his 
paddie  he  now  pushes  this  compound  irp  to  the  opposite  side  of  the  furnace,  where  it  is 
drawn  by  an  assistant  through  the  back  door  into  a  trough  containing  water.  Whilst  the 
assistant  is  doing  this  the  foreman  is  busily  engaged  in  tapping  off  the  metal  into  the 
iron  pan  in  front  of  the  furnace,  from  which,  when  sufiiciently  cooled,  it  is  laded  out 
into  suitable  moulds. 

The  total  duration  of  the  operation  may  be  about  six  hours. 

To  build  a  furnace  of  the  above  description,  5,<>0)  common  bricks,  2,000  fire-bricks, 
and  2^^  tons  of  fire-clay  are  required.  In  addition  to  this  must  be  reckoned  the  iron- 
work, the  expense  of  which  will  be  much  influenced  by  the  nature  of  the  armatures  em- 
ployed and  the  locality  in  which  the  furnace  is  constructed. 

The  amount  of  fuel  employed  for  the  treatment  of  a  ton  of  lead  ore  varies  not  only 
in  relation  to  the  richness  of  the  mineral,  but  is  also  much  influenced  by  the  nature  of 
the  associated  matrix  and  the  calorific  value  of  the  fuel  itself.  The  loss  of  metal  expe- 
rienced during  the  operation  is  mainly  dependent  on- the  richness  of  the  ore  treated  and 
the  skill  and  attention  of  the  foreman. 

In  the  north  about  12  cwt.  of  coal  are  consumed  in  the  elaboration  of  one  ton  of  ore, 
and  the  loss  of  metal  on  60  per  cent,  ore  may  be  estimated  at  about  12  per  cent.,  of 
which  about  6^  per  cent,  is  subsequently  recovered  from  the  slag  and  fumes.  At  a  well- 
conducted  smelting  works,  situated  in  the  west  of  England,  in  which  the  average  assay 
of  the  ores  smelted  d.iring  the  year  was  75^,  the  yield  from  the  smelting  furnaces  was 
6Si  per  cent.,  and  the  coal  used  per  ton  of  ore  was  13|  cwt.  The  lead  recovered  from 
the  slag  and  fumes  amounted  to  2|  per  cent.,  making  the  total  yield  of  metal  71^  per 
cent.,  and  the  loss  on  the  assay  produce  4+  per  cent. 

In  this  establishment  the  men  are  paid  from  'is.  &d.  to  12s.  Gd.  per  ton  of  lead,  in 
accordance  with  the  nature  of  the  ores  operated  on. 

In  one  establishment  the  process  before  described  is  somewhat  varied.  The  charge 
employed  is  21  cwt.  This  is  run  down  and  tapped  off  at  the  expiration  of  G  hours,  and 
about  9  pigs  of  l^  cwt.  each  usually  obtained.  A  second  charge  of  21  cwt.  is  then  drop- 
ped in,  and,  as  soon  as  it  is  roasted,  mixed  with  the  slags  of  the  former  operation.  The 
whole  is  then  run  down  in  the  ordinary  way,  the  slags  drawn  and  the  lead  tapped  off  in  9 
hours.     The  produce  of  the  second  or  double  charge  is  from  1-i  to  15  pigs. 

If  the  ores  are  difficult  to  flow,  16  to  164  hours  are  required  for  the  two  charges. 
A  small  quantity  of  black  slag  from  the  ^lag  hearth  is  employed  for  drnng  up. 

Treatment  of  lead  ores  by  the  Scotch  furnace  or  ore-hearth. — This  furnace  is  generally 
employed  in  the  counties  of  Northumberland,  Cumberland,  and  Durham,  for  the  smelt- 
ing of  lead  ores,  which  were  formerly  carried  to  tliem  without  any  preparation,  but  th^y 
are  now  often  exposed  to  a  preliminary  calcination.  The  roasted  ore  yields  in  the  Scotch 
furnace  a  more  considerable  product  than  the  crude  ore,  because  it  forms  in  the  furnace 


688  LEAD. 

a  more  porous  mass,  and  at  the  same  time  it  works  drier,  to  use  the  founder's  expres- 
sion ;  that  is,  it  allows  the  stream  of  air  impelled  by  the  blast  to  diffuse  itself  more  com- 
pletely across  the  matters  contained  in  the  furnace. 

In  proceeding  to  smelt  by  means  of  an  ore-hearth,  two  workmen  are  required  to  be 
in  attendance  from  the  bejrinning  to  the  end  of  each  smelting  shift,  the  duration  of  which 
is  from  12  to  15  hours.  The  first  step  in  commencing  a  smelting  shift  is  to  fill  up  the 
hearth-bottom  and  space  below  the  workstone  with  peats,  placing  one  already  kindled 
before  the  nozzle  of  the  bellows.  The  powerful  blast  very  soon  sets  the  whole  in  a  blaze, 
and  by  the  addition  of  small  quantities  of  coal  at  intervals,  a  body  of  fire  is  obtained, 
filling  the  hearth.  Roasted  ore  is  now  put  upon  the  surface  of  the  fire,  between  the 
forestone  and  pipestone,  which  inmiediately  becomes  heated  red  hot  and  reduced,  the 
lead  roni  it  sinking  down  and  collecting  in  the  hearth  bottom.  Other  portions  of  ore  of 
10  or  12  lbs.  each  are  introduced  from  time  to  time,  and  the  contents  of  the  hearth  are 
stirred  and  kept  open,  being  occasionally  drawn  out  and  examined  upon  the  workstone, 
until  the  hearth  bottom  becomes  full  of  lead.  The  hearth  may  now  be  considered  in  its 
regular  working  state,  having  a  mass  of  heated  fuel,  mixed  with  partly  fused  and  semi- 
reduced  ore,  called  Bronze,  floating  upon  a  stratum  of  melted  lead.  The  smelting  shift 
is  then  regularly  proceeded  with  by  the  two  workmen,  as  follows  : — The  fire  being  made  up, 
a  stratum  of  ore  is  spread  upon  the  horizontal  surface  of  the  Lrouze,  and  the  whole  suf- 
fered to  remain  exposed  to  tiie  blast  for  the  space  of  about  five  minutes.  At  the  end  of 
that  time,  one  man  plunges  a  poker  into  the  fluid  lead  in  the  hearth  bottom  below  the 
bronze,  and  raises  the  whole  up,  at  different  places,  so  as  to  loosen  and  open  the  bronze, 
and  in  doing  so,  to  pull  a  part  of  it  forwards  upon  the  workstone,  allowing  the  recently 
added  ore  to  sink  down  into  the  body  of  the  hearth.  The  poker  is  now  exchanged  for 
a  shovel,  with  a  head  6  inches  square,  with  which  the  bronze  is  examined  upon  the  work- 
stone, and  any  lumps  that  may  have  been  too  much  fused,  broken  to  pieces  ;  those  which 
are  so  far  agglutinated  by  the  heat  as  to  be  quite  hard,  and  further  known  by  their  bright- 
ness, being  picked  out,  and  thrown  aside,  to  be  afterwards  smelted  in  the  slag  hearth. 
They  are  called  "gray  slags.''  A  little  slaked  lime,  in  powder,  is  then  spread  upon  the 
bronze,  which  has  been  drawn  forward  upon  the  workstone,  if  it  exhibit  a  pasty  appear- 
ance ;  and  a  portion  of  coal  is  added  to  the  hearth,  if  necessary,  which  the  woikman 
knows  by  experience.  In  the  mean  time,  his  fellow  workman,  or  shoulder  fellow,  clears 
the  opening,  through  which  the  blast  passes  into  the  hearth,  with  a  shovel,  and  places  a 
peat  immediately  above  it,  which  he  holds  in  its  proper  situation  until  it  is  fixed  by  the 
return  of  all  the  bronze  from  the  workstone  into  the  hearth.  The  fire  is  made  up  again 
into  the  shape  before  described,  a  stratum  of  fresh  ore  spread  upon  the  part,  and  the 
operation  of  stirring,  breaking  the  lumps  upon  the  workstone,  and  picking  out  the  hard 
slags  repeated,  after  the  expiration  of  a  few  minutes,  exactly  in  the  same  manner.  At 
every  stirring  a  fresh  peat  is  put  above  the  nozzle  of  the  bellows,  which  divides  the  blast, 
and  causes  it  to  be  distributed  all  over  the  hearth  ;  and  as  it  burns  away  into  light  ashes, 
an  opening  is  left  for  the  blast  to  issue  freely  into  the  body  of  the  bronze.  The  soft  ' 
and  porous  nature  of  dried  peat  renders  it  very  suitable  for  this  purpose  ;  but,  in  some 
instances,  where  a  deficiency  of  peats  has  occurred,  blocks  of  wood  of  tiie  same  size  have 
been  used  with  little  disadvantage.  As  the  smelting  proceeds,  the  reduced  lead,  filtering 
down  through  all  parts  of  the  bronze  into  the  hearth  bottom,  flows  through  the  channel, 
out  of  which  it  is  laded  into  a  proper  mould,  and  formed  into  pigs. 

The  princijial  particulars  to  be  attended  to  in  managing  an  ore-hearth  properly  during 
the  smelting  shift,  are  these:  First. — It  is  very  important  to  employ  a  proper  blast,  which 
should  be  carefully  regulated,  so  as  to  be  neither  too  weak  nor  too  j)Owerful.  Too  weak 
a  blast  would  not  excite  the  requiaito  heat  to  reduce  the  ore,  and  one  too  powerful  has 
the  effect  of  fusing  the  contents  of  the  hearth  into  slags.  In  this  particular  no  certain 
rules  can  be  given  ;  for  the  same  blast  is  not  suitable  for  every  variety  of  ore.  Soft  free- 
grained  galena,  of  great  specific  gravity,  being  very  fusible,  and  easily  reduced,  requires 
a  moderate  blast ;  while  the  harder  and  ligiiter  varieties,  many  of  which  contain  more  or 
less  iron,  and  are  often  found  rich  in  silver,  require  a  blast  considerably  stronger.  In  all 
cases,  it  is  most  essential  that  the  blast  should  be  no  more  than  sufficient  to  reduce  the 
ore,  after  every  other  necessary  precaution  is  taken  in  working  the  hearth.  Second. — 
The  blast  should  be  as  much  divided  as  possible,  ami  made  to  pass  through  every  part  of 
the  bronze.  Third. — Tiie  hearth  should  be  vigorously  stirred,  at  due  intervals,  and  part 
of  its  contents  exposed  upon  the  workstone;  when  the  partially  fused  lumps  should  be 
well  broken  to  pieces,  as  well  as  those  which  are  further  vitrified,  so  as  to  form  slags, 
carefully  picked  out.  This  breaking  to  pieces  and  exposure  of  the  hottest  part  of  the 
bronze  upon  the  workstone,  has  a  most  beneficial  effect  in  promoting  its  reduction  into 
lead;  for  the  atmospheric  air  immediately  acts  upon  it,  and,  in  that  heated  state,  the  sul- 
phur is  readily  consumed,  or  converted  into  suliihurous  acid,  leaving  the  lead  in  its 
metallic  state  ;  hence  it  is  that  the  reduced  lead  always  flows  most  abundantly  out  of  the 
hearth  immediately  after  the  return  of  the  brouze,  which  has  been  spread  out  and  ex- 


LEAD.  689 

posed  to  the  atmosphere.  Fourth. — The  quantity  of  lime  used  should  be  no  more  than 
is  just  necessary  to  thicken  the  brouze  sufficiently  ;  as  it  does  not  in  the  least  contribute 
to  reduce  the  ore  by  auy  chemical  effect ;  its  use  is  merely  to  render  the  brouze  less  pasty, 
if,  from  the  heat  being  too  great,  or  from  the  nature  of  the  ore,  it  has  a  disposition  to 
become  very  soft.  Fifth. — Coal  should  be  also  supplied  judiciously;  too  much  unneces- 
sarily increasing  the  bulk  of  the  brouze,  and  causing  the  hearth  to  get  too  full. 

When  the  ore  is  of  a  description  to  smelt  readily,  and  the  hearth  is  well  managed  in 
everv  particular,  it  works  with  but  a  small  quantity  of  brouze,  which  feels  dry  when 
stirred,  and  is  easily  kept  open  and  permeable  to  the  blast.  The  reduction  proceeds  rapidly 
with  a  moderate  degree  of  heat,  and  the  slags  produced  are  inconsiderable  :  but  if  in 
this  state  the  stirring  of  the  brouze  and  exposure  upon  the  workstone  are  discontinued, 
or  practiced  at  longer  intervals,  the  hearth  quickly  gets  too  hot,  and  immediately  begins 
to  agglutinate  together ;  rendering  evident  the  necessity  of  these  operations  to  the  suc- 
cessful management  of  the  process.  It  is  not  difficult  to  understand  why  these  effects 
take  place,  when  it  is  considered,  that  in  smelting  by  means-  of  the  ore-hearth,  it  Ls  the 
oxygen  of  the  blast  and  of  the  atmosphere  which  principally  accomplishes  the  reduction; 
and  the  point  to  be  chiefly  attended  to  consists  in  exposing  the  ore  to  its  action,  at  the 
proper  temperature,  and  under  the  most  favorable  circumstances.  The  importance  ©f 
having  the  ore  free  from  impurities  is  also  evident ;  for  the  stony  or  earthy  matter  it 
contains  impedes  the  smelting  process,  and  increases  the  quantity  of  slags.  A  very 
slight  difference  of  composition  of  perfectly  dressed  ore  may  readily  be  understood  to 
affect  its  reducibility ;  and  hence  it  is,  that  ore  from  different  veins,  or  the  same  vein  in 
different  strata,  as  before  observed,  is  frequently  found  to  work  very  differently  when 
smelted  singly  in  the  hearth.  It  happens,  therefore,  that  with  the  best  workmen,  some 
varieties  of  ore  require  more  coal  and  lime,  and  a  greater  degree  of  heat  than  others ; 
and  it  is  for  this  reason  that  the  forestone  is  made  movable,  so  as  either  to  answer  for 
ore  which  works  with  a  large  or  a  small  quantity  of  brouze. 

It  has  been  stated  that  the  duration  of  a  smelting  shift  is  from  12  to  15  hours,  at  the 
end  of  which  time,  with  every  precaution,  the  hearth  is  apt  to  become  too  hot,  and  it  is 
necessary  to  stop  for  some  time,  in  order  that  it  may  cool.  At  mills  where  the  smelting 
shifts  is  12  hours,  the  hearths  usually  go  on  12  hours,  and  are  suspended  5  ;  four  and  a 
half  or  five  bings*  of  ore  (.36  to  40  cwt.)  are  smelted  during  a  shift,  and  the  two 
men  who  m;inage  the  hearth  work  each  four  shifts  per  week;  terminating  their  week's 
work  at  3  o'clock  on  Wednesday  afternoon.  They  are  succeeded  by  two  otherworkmen, 
who  also  work  four  12-hour  shifts;  the  last  of  wliich  they  finish  at  -i  o'clock  on  Satur- 
day. In  these  eight  shifts  from  36  to  40  bings  of  ore  are  smelted,  which,,  when  of  good 
quality,  produce  from  9  to  10  foddersf  of  lead.  At  other  mills  where  the  shift  is  14  or 
1-5  hours,  the  furnace  is  kindled  at  4  o'clock  in  the  morning,  and  worked  until  6  or  7  in 
the  evening  each  day,  six  days  in  the  week ;  during  this  shift,  5  or  5^  bings  of  ore  are 
smelted,  and  two  men  at  one  hearth,  in  the  early  part  of  each  week,  work  three  such 
shifts,  producing  about  4  fodders  of  lead — two  other  men  work  each  3  shifts  in  the  latter 
part  of  the  week,  making  the  total  quantity  smelted  per  week,  in  one  hearth,  from  SO  to 
33  bings. 

Hearth-ends  and  Smelter's  fume. — In  the  operation  of  smelting,  as  already  described, 
it  happens  that  {wrticles  of  unreduced  and  semi-reduced  ore  are  continually  expelled 
from  the  hearth,  partly  by  the  force  of  the  blast,  but  principaHT  by  the  decrepitation  of 
the  ore  on  the  application  of  heat.  This  ore  is  mixed  with  a  portion  of  the  fuel  and  lime 
made  use  of  in  smelting,  all  of  which  are  deposited  upon  the  top  of  the  smelting  hearth, 
and  are  called  hearth-ends.  It  is  customary  to  remove  the  hearth-ends  from  time  to 
time,  and  deposit  them  in  a  convenient  place  until  the  end  of  the  year,  or  some  shorter 
period,  when  they  are  washed  to  get  rid  of  the  earthy  matter  they  may  contain,  and  the 
metallic  portion  is  roasted  at  a  strong  heat,  until  it  begins  to  soften  and  cohere  into 
lumps,  and  afterward^  smelted  in  the  ore-hearth,  exactly  in  the  some  way  as  ore  under- 
going that  operation  for  tbe  first  time,  as  already  described. 

It  is  difficult  to  state  what  quantity  of  hearth-ends  are  produced  by  the  smelting  of  a 
given  quantity  of  ore,  but  in  one  instance  the  hearth-ends  produced  in  smelting  9,751 
bings,  on  being  roasted  and  reduced  in  the  oar-hearth,  yielded  of  common  lead  315  cwt., 
and  the  gray  slags  separated  in  this  process  gave,  by  treatment  in  the  slag-hearth,  47 
cwt.  of  slag  lead;  making  the  total  quantity  of  lead  362  cwt.,  which  is  at  the  rate  of  3 
cwt.  2  qrs.  23  lbs.  from  the  smelting  of  100  bings  of  ore. 

Sing-hearth. — The  various  slags  obtained  from  the  different  operations  of  lead  smelt- 
ing are  divided  into  two  cla-sses.  Those  which  do  not  contain  a  sufficient  amount  of 
metal  to  pay  for  further  treatment  are  thrown  away  as  useless,  whilst  those  in  which  the 
percentage  of  lead  is  sufficiently  large  are  treated  by  the  slag-hearth. 

Castilian  furnace. — Within  the  last  few  years  a  blast  furnace  has  been  introduced 
into  the  lead  works  of  this  country,  which  possesses  great  advantages  over  every  other 

*  1  bing  =  S  cwts,  +  1  fjd.)or  =  21  cwts. 

Vol.  III. — i4 


690  LEAD. 

description  of  ajiparatus  which  has  been  hitherto  employed  for  the  treatment  of  lead  ores 
of  low  produce.  This  apparatus,  although  first  employed  in  Spain,  was  invented  bv  an 
Englishman  (Mr.  W.  Goundry)  who  was  employed  in  the  reduction  of  rich  slags  in  the 
neighborhood  of  Carthagena. 

This  furnace  is  circular,  usually  about  2  feet  4  inches,  or  2  foct  6  inches  in  diameter, 
and  is  constructed  of  the  best  fire-bricks,  so  moulded  as  to  fit  together,  and  allow  iiU  the 
joints  to  follow  the  radii  of  the  circle  described  by  the  brickwork.  Its  usual  height  is  8 
feet  6  inches,  and  the  thickness  of  the  masonry  invariably  9  inches.  In  this  arrangement 
the  breast  is  formed  by  a  semicircular  plate  of  cast-iron,  furnished  with  a  lip  for  running 
oif  the  slag,  and  has  a  longitudinal  slot,  in  which  is  placed  the  tapping-hole. 

On  the  top  of  this  cylinder  of  brickwork,  a  box-shaped  covering  of  masonry  is  sup- 
ported by  a  cast-iron  framing,  resting  on  four  pillars,  and  in  this  is  placed  the  door  for 
ieeding  the  furnace,  and  the  outlet  by  which  the  various  products  of  combustion  escape 
to  the  flues.  The  lower  part  of  this  hood  is  fitted  closely  to  the  body  of  the  furnace, 
whilst  its  top  is  closed  by  an  arch  of  4T!-inch  brickwork  laid  in  fire-clay.  The  bottom  is 
composed  of  a  mixture  of  coke-dust  and  fire-clay,  slightly  moistened,  and  well  beaten  to 
the  height  of  the  top  of  the  breast-pan,  which  stands  nearly  3  feet  above  the  level  of  the 
floor.  Above  the  breast-pan  is  an  arch,  so  turned  as  to  form  a  soit  of  niche,  18  inches 
in  width  and  rather  more  than  2  feet  in  height. 

When  the  bottom  has  been  solidly  beaten,  up  to  the  required  height,  it  is  hollowed 
out  so  as  to  form  an  internal  cavity,  communicating  freely  with  the  brea.=t-pan,  which  is 
filled  with  the  same  material  and  subsequently  hollowed  out  to  a  depth  sliglitly  below  the 
level  of  the  internal  cavity.  The  blast  is  supplied  by  three  water  tuyeres,  3  inches  in 
diameter  at  the  smaller  end,  5^  inches  at  the  larger,  and  1(»  inches  in  length.  Into  these 
the  nozzles  are  introduced,  by  which  a  cm-rent  of  air  is  supplied  by  means  of  a  fan  or 
vcntilatoi',  making  about  SoO  revolutions  per  minute.  The  blast  may  be  conveniently 
conducted  to  the  nozzles  through  brick  channels  formed  beneath  the  floor  of  the  smelt- 
ing house. 

The  ores  treated  in  this  furnace  ought  never  to  contain  more  than  30  per  cent,  of 
metal,  and  when  richer,  must  be  reduced  to  about  this  tenure  by  the  addition  of  slags  and 
other  fluxes.  In  charging  this  apparatus,  the  coke  and  ore  are  supplied  stratum  super 
stratum,  and  care  must  be  taken  so  to  dispose  the  coke  as  not  to  heat  too  violently  the 
brickwork  of  the  furnaces.  In  order  to  allow  the  slags  which  are  produced  to  escape 
freely  into  the  breast-pan,  a  brick  is  left  out  of  the  front  of  the  furnace  at  the  height  of 
tlie  fore-hearth,  which,  for  the  purpose  of  preventing  the  cooling  of  the  scoriae,  is  kept 
covered  by  a  layer  of  coke-dust  or  cinders.  From  the  breast  pan  the  slags  flow  constant- 
ly off  over  a  spout  into  cast-iron  wagons,  where  they  consolidate  into  masses,  having  the 
form  of  truncated  pyramids,  of  which  the  larger  base  is  about  2  feet  square.  As  soon  as 
a  sufficient  amount  of  lead  is  accumulated  in  the  bottom  of  the  furnace,  it  is  let  off  into 
a  lateral  lead-pot,  by  removing  the  clay-stopper  of  the  tap-hole  situated  in  the  slot  of  the 
breast-pan,  and  after  being  properly  skimmed  it  is  laded  into  moulds  When  in  addition 
to  lead,  the  ore  treated  likewise  contains  a  certain  portion  of  copper,  this  metal  will  be 
found  in  the  form  of  a  matt  floating  on  the  surfi.ce  of  the  leaden  bath.  This,  when  suf- 
ficiently solidified,  is  removed,  and  after  being  loastcd  is  operated  on  for  the  copper  it 
contains.  » 

The  wagons  in  which  the  liquid  slag  runs  off,  are  frequently  made  to  traverse  small 
railways,  by  which,  when  one  mass  has  been  removed,  its  place  may  readily  be  supplied 
by  an  empty  wagon.  When  nearly  cold  the  casings  of  the  wagons  are  turned  over  and 
the  blocks  of  slag  easily  made  to  drop  out.  In  addition  to  the  facility  for  transport 
obtained  in  this  way,  one  of  the  great  advantages  obtained  by  this  method  of  manipu- 
lation arisesfrom  the  circumstance,  that  should  the  furnaces  at  any  time  run  lead  or  matt, 
without  its  being  detected  by  the  smelter,  the  whole  of  it  will  be  collected  at  the  bottom 
of  the  block,  from  which,  when  cold,  it  may  be  readily  detached. 

In  working  these  furnaces,  care  must  be  taken  to  jirever.t  flame  from  appearing  at 
the  tunnel-head,  since,  provided  the  slags  are  sufficiently  liquid,  the  cooler  the  apparatus 
is  kept  the  less  will  be  the  loss  of  metal  through  volatilization.  In  addition  to  the  great- 
est attention  being  paid  to  the  working  of  the  furnace,  it  is  necessary,  in  order  to  obtain 
the  best  results,  that  all  establishments  in  which  this  apparatus  is  employed  should  be 
provided  with  long  and  capacious  flues,  in  which  the  condensation  of  the  fumes  takes 
place,  previous  to  arriving  at  the  chimney-shaft.  These  flues  should  be  built  at  least 
three  feet  in  width  and  six  feet  in  height,  so  as  readily  to  admit  of  being  cleaned,  and 
are  often  made  of  several  thousand  yards  in  length.  The  value  of  the  fumes,  so  con- 
densed, amounts  to  many  hundreds,  and  in  some  instances  thousands  per  annum. 

In  order  to  be  advantageously  worked  in  these  furnaces,  the  ores  should  be  first  roast- 
ed, and  subsequently  agglomerated  into  masses,  which,  afrer  being  broken  into  fragments 
of  about  the  size  of  the  fist,  and  mixed  with  the  various  fluxes,  are  charged  as  before 
described. 


LEAD. 


691 


In  an  establishment  in  which  the  average  assay  produce  of  the  roasted  ore  for  lead 
is  42*  stbs,  the  furnace  yield  is  38"  nths,  and  the  weight  of  coke  employed  to  eflect  the 
reduction  22  per  cent,  of  the  roasted  ore  operated  on.  The  mixture  charged  into  the 
furnace,  in  this  instance,  is  composed  of  luu  parts  of  roasted  ore,  42  parts  of  slags  from 
a  previous  operation,  8  parts  of  scrap  iron,  and  7  parts  of  limestone.  Each  furnace 
works  off  about  seven  tons  of  roasted  ore  in  the  course  of  24  hours  ;  the  weight  of  slags 
ruji  off  is  about  double  that  of  the  lead  obtained,  and  the  matt  removed  from  the  surface 
of  the  pan  is  nearlv  5  per  cent,  of  the  lead  produced.  The  ores  treated  in  this  establish- 
ment consist  of  galena,  much  mixed  with  spathose  iron,  and  are  therefore  somewhat  re- 
fractorv.  A  furnace  of  this  kind  requires  for  its  construction  about  1,000  segmental  fire- 
bricks, and  the  same  number  of  ordinary  fire-bricks  of  second  quaUty. 

374  ST 5 


692 


LEAD. 


Fifjs.  374,  375,  376,  and  377  represent  respectively  a  vertical  section,  an  elevation, 
a  grouml  plan,  and  a  horizontal  section  of  a  Castilian  furnace.  The  section  {fig.  377)  is 
oil  the  line  x  y,  {fig.  375.)  a  is  the  body  of  the  furnace,  b,  the  bottom  composed  of  a 
nii.^turc  of  coke-diist  and  fire-clay;  c  c  c,  the  tuyeres;  d,  the  rectangular  covering  of 
masonry ;  E  e  E  e,  cast-iron  pillars  ,  F,  the  breast-pan ;  g,  slot  for  tapping  hole  ;  n,  lip  of 
breast-jiiiu  ;  i,  feeding  door;  k,  Hue-hole;  p,  q,  ground  line. 

Figs.  378,  379  are  the  sLig-wasons,  a  being  a  movable  case  without  a  bottom,  and 
B  a  strong  cast-iron  plate  running  on  four  wheels. 

378 


The  dosulphuration  of  the  ores  to  be  treated  in  these  furnaces  may  be  effected  either 
by  the  aid  of  an  ordinary  reverberatory  roasting  furnace,  or  in  heaps,  or  properly  con- 
structed kilns. 

The  Kilns  bi>st  adapted  for  this  purpose  consist  of  rectangular  chambers,  having  an 
arched  roof,  and  provided  with  proper  fines  for  the  escape  of  the  evolved  gases,  as  well 
as  a  wide  door  for  charging  and  withdrawing  the  ore  to  be  operated  on. 

Eich  of  these  chambers  is  capable  of  containing  from  25  to  30  tons  of  ore,  and,  in 
onier  to  ih^rge  it,  a  hiycr  of  faggots  and  split  wood  is  laid  on  the  floor,  and  this,  after 
having  been  covered  by  a  layer  of  ore  about  two  feet  in  thickness,  is  ignited,  care  being 
at  the  same  time  taken  to  close,  by  means  of  loose  brick-work,  the  opening  of  the  door 
to  the  same  height.  When  this  first  layer  has  become  sufficiently  ignited,  a  fresh  stratum 
of  ore,  mixed  with  a  little  coal  or  charcoal,  is  thrown  upon  it,  and  when  this  layer  has  in 
its  turn  become  sufficiently  heated,  more  ore  is  thrown  on.  In  this  way,  more  ore  is  from 
time  to  time  added,  until  the  kiln  has  become  full,, when  the  orifice  of  the  doorway  is 
closed  by  an  iron  plate,  and  the  operation  proceeds  regularly  and  without  further  trouble 
until  the  greater  portion  ha-;  become  eliiidnated. 

This  us'ially  happens  at  tlio  expiration  of  about  four  w  eeks  from  the  time  of  first  igni- 
tion, and  tlie  brick-work  front  is  then  removed,  and  the  ores  broken  out,  and,  after  being 
mixed  with  proper  flu.xes,  passed  through  the  blast  furnace. 

The  propoitir)n  of  wood  necessary  for  the  roasting  of  a  ton  of  ore  by  this  means,  nmst 
necessiirily  defx-nd  on  the  composition  of  the  minerals  operated  on  ;  but  with  ores  of  the 
dcscri[)tion  nbove  mentioned,  and  in  a  neighborhood  where  wood  is  moderately  cheap, 
the  desul|ihuialion  may  be  effected  at  a  cost  of  about  6s.  per  ton. 

Calcining — The  lead  obtained  by  the  various  processes  above  described,  generally 
contains  a  snfTieictit  amount  of  silver  to  render  its  extraction  of  much  importance;  but,  in 
aildition  to  tliis,  it  is  not  unfrequently  associated  with  antimony,  tin,  copper,  and  various 
other  impurities,  which  require  to  be  removed  before  the  separation  of  the  silver  can  be 
effected. 

This  operation  consists  in  fusing  tlie  hard  lead  in  a  reverberatory  furnace  of  peeidiar 
construi-tio'i,  and  allowing  it  to  reinaiii,  when  in  a  melted  state,  exposed  to  the  oxidizing 
influences  of  the  gases  passing  through  the  apparatus.  By  this  treatment  the  antimony, 
copper,  and  other  impurities  become  oxidized,  and  on  rising  to  the  surface  of  the  metallic 
bath  are  skimmed  ofl",  and  removed  with  an  iron  rake.  The  hearth  of  the  furnace  in 
which  this  operation  is  conducted  consists  of  a  large  cast-iron  pan,  which  may  be  10  feet 
in  length,  5  feet  t;  inclics  in  width,  and  10  inches  in  depth.  The  fire-place,  which  is  1 
foot  8  iiiciies  in  width,  has  a  length  equal  to  the  width  of  the  pan,  and  is  separated  from 
it  by  a  fire-bridge  '1  feet  in  width.  The  height  of  the  arch  at  the  bridge  end  is  1  foot  4 
inches  above  the  edge  of  the  pan,  whilst  at  the  outer  extremity  it  is  only  about  8  inches. 

The  lead  to  be  introduced  into  the  pan  is  first  fused  in  a  large  iron  ]>ot  fixed  in  brick- 
work at  the  side  of  the  furnace,  and  subsequently  laded  into  it  through  an  iron  gutter 


LEAD. 


693 


adapted  for  that  purpose.  The  length  of  time  necessary  for  the  purification  of  hard  lead 
obviously  depends  on  the  nature  and  amount  of  the  impurities  which  it  contains;  and, 
consequently,  some  varieties  will  be  sufficiently  improved  at  the  expiration  of  twelve  hours, 
whilst  in  other  instances  it  is  necessary  to  continue  the  operation  during  three  or  four 
weeks.     The  charge  of  hard  lead  varies  from  eight  to  eleven  tons. 

When  the  metal  is  thought  to  be  in  a  fit  state  for  tapping,  a  small  portion  taken  out 
with  a  ladle,  and  poured  into  a  mould  used  for  this  purpose  is  found  on  cooling  to  assume 
at  the  surface  a  peculiar  crystalline  appearance,  which  when  once  seen  is  readily  agiin  rec- 
ognized. As  soon  as  this  appearance  presents  itself,  an  iron  plug  is  withdrawn  from  the 
bottom  of  the  pan,  and  the  lead  run  oif  into  an  iron  pan,  from  which  it  is  subsequently 
laded  into  moulds. 

The  items  of  cost  attending  the  calcination  of  one  ton  of  hard  Spanish  lead  iii  the 
north  of  England  are  about  as  follows :—' 


Wages 

Coals,  2-7  cwt. 
Repairs,  &c. 


d. 

11-2 

4-7 

0-5 


2     4-4 
The  coBstruction  of  a  furnace  of  this  description  requires  5,000  common  bricks,  3,500 
fire-bricks,  and  i  tons  of  firc-:lay. 

Figs.  380  and  381  represent  an  elevation  and  vertical  section  of  the  calcining  furnace. 


E 


m 


E 


E 


3S1 


A  is  the  fire-place  ;  b,  ash-pit ;  c,  fire-bridge;  d,  cast-iron  pan ;  e,  flue ;  r  K  F,  channels  for 

allowing  the  escape  of  moisture ;  g,  one  of  the  working  doors ;  b,  spout  for  running  off 

calcined   metal.     Fi^.  382    represents  the  pan 

removed  from  the  masonry,  and  shows  a  groove 

in  the  hp  for  the  introduction  of  a  sheet-iron 

dam    tightened   with    moistened   bone-ash,  for 

keeping  in  the  fused  metal. 

In  the  more  modern  furnaces  of  this  de- 
scription, the  corners  are  usually  rounded  to 
prevent  breakage  from  expansion,  whilst  the 
tapping  is  effected  by  means  of  a  hole  through 
tiie  bottom  near  one  of  the  sides.  This,  when 
closed,  is  stopped  by  means  of  an  iron  plug  kept 
in  its  place  by  a  weighted  lever. 

Concentration  of  the  silver. — This  process 
is  founded  on   the  circumstance   first   noticed 

in  the  year  1829,  by  the  late  H.  L.  Pattinson  of  Newcastle-on-Tyne,  that  when  lead  con- 
taining' silver  is  melted  in  a  suitable  vessel,  afterwards  slowly  allowed  to  cool,  and  at  the 
same  kept  constantly  stirred,  at  a  certain  temperature  near  the  melting  point  of  lead. 


^i: 


694 


LEAD. 


383 


384 


metallic  crystals  begin  to  form.  These  as  rapidly  as  they  are  produced  sink  to  the  bot- 
tom, and  on  being  removed  are  found  to  contain  much  less  silver  than  the  lead  originally 
operated  on.  The  still  fluid  portion,  from  which  the  crystals  have  been  removed,  will  at 
the  same  time  be  proportionally  enriched. 

This  operation  is  conducted  in  a  series  of 
8  or  10  cast  iron-pots,  set  in  a  row,  with  fire- 
places beneath.  These  are  each  capable  of 
containing  about  6  tons  of  calcined  lead ;  and 
on  commencing  an  operation,  that  quantity  of 
metal,  containing  we  will  suppose  20  oz.  of 
silver  per  ton,  is  introduced  into  a  pot  (say  r, 
fir).  383)  about  the  centre  of  the  series.  This, 
when  melted,  is  carefully  skimmed  with  a  per- 
forated ladle,  and  the  fire  immediately  with- 
drawn. The  cooling  of  the  metal  is  also  fre- 
quently hastened  by  throwing  water  upon  its 
surface,  and  whilst  cooling  it  is  kept  constantly 
agitated  by  means  of  a  long  iron  stirrer  or 
slice.  Crystals  soon  begin  to  make  their  ap- 
pearance, and  these  as  they  accumulate  and 
fall  to  the  bottom  are  removed  by  means  of  a 
large  perforated  ladle,  in  which  they  are  well 
shaken,  and  afterwards  carried  over  to  the 
next  pot  to  the  left  of  the  workman.  This 
operation  goes  on  continually  until  about  4 
tons  of  crystals  have  been  taken  out  of  the 
pot  F,  and  have  been  placed  in  pot  e,  at  which 
time  the  pot  f,  may  contain  about  40  oz.  of 
silver  to  the  ton,  whilst  that  in  e,  will  only 
yield  10  oz.  The  rich  lead  in  f  is  then  laded 
into  the  next  pot  g,  to  the  right  of  the  work- 
man, and  the  operation  repeated  in  f,  on  a 
fresh  quantity  of  calcined  lead. 

In  this  way,  calcined  lead  is  constantly 
introduced,  and  the  resulting  poor  lead  passes 
continually  to  the  left  of  the  workman,  whilst 
the  rich  is  passing  towards  his  right.  Each 
pot  in  succession,  when  filled  with  lead  of  its 
proper  produce  for  silver,  is  in  its  turn  crys- 
tallized, the  poor  lead  passing  to  the  left  of 
the  workman,  and  the  enriched  lead  to  his 
right.  By  this  method  of  treatment,  it  is  evi- 
dent that  the  crystals  obtained  from  the  pots 
to  the  left  of  the  workman  must  gradually  be 
deprived  of  their  silver,  whilst  the  rich  lead 
passing  to  his  right  becomes  continually  richer. 
The  final  result  is,  that  at  one  end  of  the  series, 
the  poor  lead  contains  very  little  silver,  whilst 
at  the  other  an  exceedingly  rich  alloy  of  lead 
and  silver  is  obtained. 

The  poor  lead  obtained  by  this  process 
should  never  contain  more  than  12  dwts.  of 
silver  per  ton,  whilst  the  rich  lead  is  fre- 
quently concentrated  to  500  oz.  to  the  ton. 
This  rich  lead  is  subsequently  cupelled  in  the 
refining  furnace. 

The  ladle  employed  for  the  removal  of  the 
crystals,  when  manual  labor  is  made  use  of, 
is  about  16  inches  in  diameter,  and  5  inches  in 
depth,  but  when  cranes  are  used  much  larger 
ladles  are  easily  managed.  A  form  of  crane 
has  been  invented  which  effects  considerable 
economy  of  labor  in  this  operation.  When, 
during  the  operation  of  crystallization,  the 
ladle  becomes  chilled,  it  is  dipped  in  a  small 
vessel  containing  lead  of  a  higher  temperature 
known   by  the   name   of  a   temper-pot.     The  pot 


than   that  which   is  beincr  worked,  and 


LEAD. 


695 


containing  the  rich  lead  is  generally  called  the  No.  1  pot ;  in  some  establishments,  howerer, 
the  last  pot  in  which  the  poor  lead  is  crystallized  obtains  this  appellation. 

Ficfs.  383  and  384  represent  a  plan  and  elevation  of  a  set  of  Pattinson's  pots,  arranged 
in  the  most  approved  way.  a  is  the  "  market  pot,"  from  which  the  desilverized  lead  is 
laded  out.  b,  c,  d,  e,  f,  g,  h,  and  i,  are  the  working  pots,  whilst  a',  b',  c',  d',  e',  f',  g',  h', 
and  I,  are  their  respective  fireplaces.  The  "  temper-pots"  a  a  a  a,  are  employed  for  heating 
the  ladles  when  they  have  become  too  much  reduced  in  temperature. 

Thejjgs.  385  and  386  are  sections  showing  the  manner  of  setting  and  the  arrangement 
of  the  pots  and  flues,     a,  pot ;  b,  main  flue ;  c,  ash  pit. 


886 


The  cost  of  crystallizing  one  ton  of  calcined  Spanish  lead,  in  the  establishment  quoted 
when  treating  of  calcination,  is  as  follows ; — 

s.     d. 

"Wages 9     5-4 

Coals,  4  cwt. 0     8-4 

Repairs 0     2-5 

Total 10    4-3 

The  erection  of  nine  six-ton  pots  requires  15,000  common  bricks,  10,000  fire-bricks, 
160  feet  of  quarles,  80  fire-clay  blocks,  and  5  tons  of  fire-clay. 

In  some  establishments,  ten-ton  pots  are  employed,  and  where  cranes  are  made  use  of 
they  are  found  to  be  advantageous. 

Jiejininrf. — The  extraction  of  the  silver  contained  in  the  rich  lead  is  conducted  in  a  cupel 
forming  the  bottom  of  a  reverbcratory  furnace  called  a  refinery. 

In  this  operation  the  litharge  produced,  instead  of  being  absorbed  by  the  substance  of 
the  cupel,  is  run  off  in  a  fluid  state,  by  means  of  a  depression  called  a  gate. 

The  size  of  the  fire-place  varies  with  the  other  dimensions  of  the  furnace,  but  is  usually 
nearly  square,  and  in  an  apparatus  of  ordinary  size  may  be  about  2  feet  -(-  2  feet  C  inches. 
This  is  separated  from  the  body  of  the  furnace  by  a  fire-bridge  18  inches  in  breadth,  so  that 
the  flame  and  heated  air  pass  directly  over  the  surface  of  the  cupel,  and  from  thence  escape 
by  means  of  two  separate  apertures  into  the  main  flues  of  the  establishment.  The  cupel  or 
test  consists  of  an  oval  iron  ring,  about  5  inches  in  depth,  its  greatest  diameter  being  4  feet  and 
its  lesser  nearly  3  feet.  This  frame,  in  order  to  better  support  the  bottom  of  the  cupel,  is 
provided  with  cross-bars  about  i^  inches  wide,  and  one-half  inch  in  thickness.     In  order  to 


696  LEAD. 

make  a  test,  this  frame  is  beaten  full  of  finely-powdered  bone-ash,  slightly  moistened  with 
water,  containing  a  small  quantity  of  pearl-ash  in  solution,  which  has  the  property  of  giving 
consistency  to  the  cupel  when  heated. 

The  centre  of  the  test,  after  the  ring  has  been  well  filled  with  this  mixture,  and  solidly 
beaten  don-n,  is  scooped  out  with  a  small  trowel,  until  the  sides  are  left  2  inches  in  thickness 
at  top,  and  3  inches  at  the  bottom,  whilst  the  thickness  of  the  sole  itself  is  about  1  inch. 

At  the  fore  part  or  wide  end  of  the  test,  tlie  thickness  of  the  border  is  increased  to  6 
inches,  and  a  hole  is  then  cut  through  the  bottom,  which  communicates  with  the  openings  or 
gates  by  which  the  fluid  litharge  makes  its  escape. 

The  test,  when  thus  prepared,  is  placed  in  the  refinery  furnace,  of  which  it  forms  the 
bottom,  and  is  wedged  to  its  proper  height  against  an  iron  ring  firmly  built  into  the  masonry. 
When  this  furnace  is  first  lighted,  it  is  necessary  to  apply  the  heat  very  gradually,  since  if 
the  test  were  too  strongly  heated  before  it  became  perfectly  dry,  it  would  be  liable  to 
crack.  As  soon  as  tlie  test  has  become  thoroughly  dry,  it  is  heated  to  incipient  redness, 
and  is  nearly  filled  with  the  rich  lead  to  be  operated  on,  which  has  been  previously  fused  in 
an  iron  pot  at  the  side  of  the  furnace,  and  beneath  which  is  a  small  grate  where  a  fire  is 
1  ghted. 

The  melted  lead,  when  first  introduced  into  the  furnace,  becomes  covered  with  a 
grayish  dross,  but  on  further  increasing  the  heat,  the  surface  of  the  bath  uncovers,  and 
ordinary  litharge  begins  to  make  its  appearance. 

The  blast  is  now  turned  on,  and  forces  the  litharge  from  the  back  of  the  test  up  to  the 
breast,  where  it  passes  over  the  gate,  and  tails  through  the  aperture  between  the  bone-ash 
and  the  ring  into  a  small  cast-iron  pot  running  on  wheels.  The  air,  which  is  supplied  by  a 
small  ventilator,  not  only  sweeps  the  litharge  from  the  surface  of  the  lead  towards  the 
breast,  but  also  supplies  the  oxygen  necessary  for  its  formation. 

In  proportion  as  the  surface  of  the  lead  becomes  depressed  by  its  constant  oxidation, 
and  the  continual  removal  of  the  resulting  litharge,  more  metal  is  added  from  the  melting 
pot,  so  as  to  raise  it  to  its  former  level,  and  in  this  manner  the  operation  is  continued  until 
the  lead  in  the  bottom  of  the  test  has  become  so  enriched  as  to  render  it  necessary  that  it 
should  be  tapped.  The  contents  of  the  test  are  now  so  far  reduced  in  volume  that  the 
whole  of  the  silver  contained  in  the  rich  lead  operated  on  remains  in  combination  with  a 
few  hundred  weight  only  of  metal,  and  this  is  removed  by  carefully  drilling  a  hole  in  the 
bone-ash  forming  the  bottom  of  the  test.  The  reason  for  the  remgval  of  the  rich  lead,  is  to 
I)revent  too  large  an  amount  of  silver  from  being  carried  off  in  the  litharge,  which  is  found 
to  be  the  case  when  lead  containing  a  very  large  amount  of  that  metal  is  operated  on. 

When  the  rich  lead  has  been  tlius  removed,  the  tapping-hole  is  again  closed  by  a  pellet 
of  bone-ash,  and  another  charge  immediately  introduced. 

As  soon  as  the  whole  of  the  rich  lead  has  been  subjected  so  cupellation,  and  has  become 
thus  further  enriched,  the  argentiferous  alloy  is  itself  similarly  treated,  either  in  a  fresh  test, 
or  in  that  employed  for  the  concentration  of  the  rich  lead.  The  brightening  of  pure  silver  at 
the  moment  of  the  separation  of  the  last  traces  of  lead,  indicates  the  precise  period  at  which 
the  operation  should  be  terminated,  and  the  blast  is  then  turned  off,  and  the  fire  removed 
from  the  grate.  The  silver  is  now  allowed  to  set,  and  as  soon  as  it  has  become  hardened,  the 
wedges  are  removed  from  beneath  the  test,  which  is  placed  on  the  floor  of  the  establishment. 
When  cold,  the  silver  plate  is  detached  from  the  test,  and  any  adhering  particles  of  bone- 
ash  removed  by  the  aid  of  a  wire  brush. 

A  test  furnace  of  ordinary  dimensions  requires  for  its  construction  about  2,000  common 
bricks,  2,000  fire-bricks,  and  H  tons  of  fire-clay.  A  furnace  of  this  kind  will  work  off  4 
pigs  of  lead  per  hour,  and  consume  4  cwt.  of  coal  per  ton  of  rich  lead  operated  on. 

The  cost  of  working  a  ton  of  rich  lead  in  the  neighborhood  of  Newcastle,  containing  on 
an  average  400  oz.  of  silver  per  ton,  is  as  follows  :  — 

s.     d. 

Refiner's    wages 42'1 

Coals,  4  cwt. 06-8 

Engine  wages .-         17 '0 

Coals,  5  cwt. 0     8-7 

Pearl-ash  0     3-5 

Bone-ash,  17-3  lbs. 3     1-0 

Repairs 0     5-0 

Total 10  10-1 

Figs.  387,  388,  and  389,  represent  an  elevation,  plan,  and  section  of  a  refining  furnace  ; 
A,  fireplace ;  b,  ash-pit ;  c,  fire-bridge  ;  d,  test-ring,  sho^^Ti  in  its  proper  position  ;  e,  flues  ; 
F,  point  where  blast  enters ;  g,  pig-holes.* 

*  Pig-holes  are  used  for  introducing  the  lead  In  cases  in  which  it  is  not  laded  into  the  test  in  a  fused 
itate. 


E.ducir,,.-T,e  reduction  to  thc.n,eta  iic  «  J^  "  ,  ,  ^  S  cJ"S  S^c^^'-^ 
po,,  ,l,oss,  a^d  the  mixed  metallic  -''  '^  ^'7;  '  uin^S  ' wo  ex^^^^^  hat  its  din,ension« 
'v,.,.l,erato.7  apparatus,  somwhat  re^e^W,  g  ^^j^'^^^^-^/^^Su-'lv  below  "the  n.iddle  .loor, 
an-  suKdhT,  and  the  sole    instead  of  ''^^    owest  im  u  j  aepression  in  xvhieh 

gradually  slope. from  .he  ^^^:^]'\^";:';;^ZX^nJ^o^X^f^ou.  M  the  reduced 

i;;;:^^fl::i=e;:i;;uS:'i.S -ulNr  i:::;&y  ^h^  side  of  the  t^maco  ^o.  ■..  recep. 

^'^'^^^^S;g':?';rr^!;  ist:th:a;d;m;S  ..th  a  quantity  of  smaU  coal,  and  i. 


698  LEAD. 

charged  on  that  part  of  the  hearth  immediately  before  the  fire-bridge.  To  prevent  the 
fused  oxide  from  attacking  the  bottom  of  the  furnace,  and  also  to  provide  a  sort  of  hollow 
filter  for  the  liquid  metal,  the  sole  is  covered  by  a  layer  of  bituminous  coal. 

The  heat  of  the  furnace  quickly  causes  the  ignition  of  this  stratum,  which  is  rapidly 
reduced  to  the  state  of  a  spongy  cinder.  The  reducing  gases  present  in  the  furnace,  aided 
by  the  coal  mixed  with  the  charge  itself,  cause  the  reduction  of  the  oxide,  which,  assum- 
ing the  metallic  form,  flows  through  the  interstices  of  the  cinder,  and  ultimately  finding 
its  way  into  the  depression  at  the  extremity  of  the  hearth,  flows  through  the  iron  gutter 
into  the  external  cast-iron  pot.  The  surface  of  the  charge  is  frequently,  during  the  pro- 
cess of  elaboration,  turned  over  with  an  iron  rake,  for  the  double  purpose  of  exposing 
new  surfaces  to  the  action  of  the  furnace,  and  also  to  allow  the  reduced  lead  to  flow  ofl" 
more  readily. 

Fresh  quantities  of  litharge  or  pot  dross,  with  small  coals,  are  from  time  to  time 
thrown  in,  in  proportion  as  that  already  charged  disappears,  and  at  the  end  of  the  shift, 
which  usually  extends  over  12  hours,  the  floor  of  cinder  is  broken  up,  and  after  being 
mixed  with  the  residual  matters  in  the  furnace,  is  withdrawn.  A  new  floor  of  cinders  is 
then  introduced,  and  the  operation  commenced  as  before.  A  furnace  of  this  kind,  having 
a  sole  8  feet  in  length  and  7  feet  in  width,  will  aflbrd,  from  litharge,  about  5^  tons  of  lead 
in  24  hours. 

The  dross  from  the  calcining  pan,  when  treated  in  a  furnace  of  this  description,  should 
be  previously  reduced  to  a  state  of  fine  division,  and  intimately  mixed  up  with  small  coal 
and  a  soda-ash.  In  many  cases,  however,  the  calcined  dross  is  treated  in  the  smelting 
furnace.  The  hard  lead  obtained  from  this  substance  is  again  taken  to  the  calcining  fur- 
nace, for  the  purpose  of  being  softened. 

The  expense  of  reducing  one  ton  of  litharge  may  be  estimated  as  follows : — 

s.  d. 

Wages 2  60 

Coals,  3  cwt. 0  5-2 

Repairs -0  1*6 

Total      -        -        -        -        3     0-8 
In  the  establishment  from  which  the  foregoing  data  were  obtained,  the  cost  of  slack, 
delivered  at  the  works,  was  only  2s.  \\d.  per  ton,  which  is  cheaper  than  fuel  can  be  ob- 
tained in  the  majority  of  the  lead-mills  of  this  country.     In  North  Wales  the  cost  of  small 
coal  is  generally  about  4s.,  and  at  Bristol  5s.  6</.  per  ton. 

Figs.  390  and  391  represent  a  vertical  section  and  plan  of  a  reducing  furnace,  a,  fire- 
place :  B,  ash-pit ;  c,  fire-bridge  :  d,  hearth ;  e,  working-door ;  f,  iron  spout  for  conduct- 
ing the  reduced  metal  into  the  lead-pot  g,  which  is  kept  heated  by  means  of  a  fire  be- 
neath. 

The  total  cost  of  elaborating  one  ton  of  hard  lead,  containing  30  oz.  of  silver  per  ton, 
in  a  locahty  in  which  fuel  is  obtained  at  the  low  price  above  quoted,  is  nearly  as  follows : 

£    s.    d. 

Calcining 0     2     4*4 

Crystallizing 09     6-5 

Refining 0     0     9-2 

Reducing — pot  dross  and  litharge   -        -         -         -       0     1     0-8 

Calcined  dross 008-0 

Slags 0     0     5-0 

Bone-ash,  &c. 0     0     7-0 

Transport,  &c. 0     11-0 

Management,  taxes,  and  interest  of  plant        -        -      0     5  10*0 

Total        -         -         .         -       1     2     3-9 

One  hundred  tons  of  hard  lead  treated  gave  :— 

Tons. 

Soft  lead 94-90 

Black  dross 3-72 

Loss 1-38 

Total 100-00 

On  comparing  the  expense  of  each  operation,  as  given  in  the  foregoing  abstract,  with 
the  amounts  stated  as  the  cost  of  each  separate  process,  they  will  be  found  to  be  widely 
different;  but  it  must  be  remembered  that  the  whole  of  the  substances  elaborated  are  far 
from  being  subjected  to  the  various  treatments  described. 

In  order  therefore  to  give  an  idea  of  the  relative  proportions  which  arc  passed  through 


LEAD. 


699 


the  several  departments,  I  may  state,  that  in  an  establishment  in  which  the  ores  are  treat- 
ed in  the  Castilian  furnace,  the  following  were  the  results  obtained : — 
One  hundred  parts  of  raw  ore  yield  : — 

Roasted  ore ..-.85 

Hard  lead 42 

Soft      " 36 

Rich     " 9 

Dross  and  litharge  re-treated 18^ 

390 


It  may  be  remarked,  that  for  the  treatment  of  ores  of  good  produce,  the  rererberatory 
furnace  and  Scotch  hearth  are  to  be  preferred,  but  for  working  minerals  of  a  low  percent- 
age the  blast  furnace  may  generally  be  substituted  with  advantage.  The  slag-licarth, 
from  the  amount  of  fuel  consumed  and  loss  experienced,  is  a  somewhat  expensive  ap- 
paratus, and  might  in  many  cases  be  advantageously  exchanged  for  the  Castilian  furnace. 

It  is  well  known  that  the  losses  which  take  place  in  this  branch  of  metallurgy  are, 
from  the  volatility  of  tlie  metal  operated  on,  unusually  large.  In  those  establishments, 
however,  in  which  due  attention  is  paid  to  fluxes  and  a  proper  admixture  of  ores,  as  well 
as  the  condensation  of  the  fumes,  a  great  economy  is  effected. 

In  some  instances,  flues  of  above  five  miles  in  length  have  been  constructed,  and  the 
most  satisfactory  results  obtained.  The  attention  of  lead  smelters  is  being  daily  more 
directed  to  the  prevention  of  the  loss  of  metal  by  volatilization,  and  those  who  have  adapt- 
ed the  use  of  long  flues  have  been,  in  all  cases,  quickly  repaid  for  their  outlay. 

As  an  example  of  the  great  extent  to  which  sublimation  may  take  place  on  the  scale 
employed  in  large  smelting  works,  we  may  mention  the  lead  works  belonging  to  Mr.  Beau- 


700  LEAD  ORES,  ASSAY  OF. 

mont  in  Northumberland.  Formerly  the  fumes  or  smoke  arising  from  various  smelting 
operations  escaped  from  ordinary  chimneys  or  short  galleries,  and  large  quantities  of  lead 
were  thus  carried  off  in  the  state  of  vapor,  and  deposited  on  the  surrounding  land,  where 
vegetation  was  destroyed,  and  the  health  of  both  men  and  other  animals  seriously  affect- 
ed. This  led  to  various  extensions  of  the  horizontal  or  slightly  inclined  galleries  now  in 
use,  and  the  quantity  of  lead  extracted  rapidly  repaid  the  cost  of  construction.  The 
latest  addition  of  this  kind  was  made  at  Alien  Mill,  by  Mr.  Sopwith,  the  manager,  and 
completed  a  length  of  8,789  yards  (nearly  five  miles)  of  stone  gallery  from  that  mill  alone. 
This  gallery  is  S  feet  high  and  6  wide,  and  is  in  two  divisions  widely  separated.  There 
are  also  upwards  of  4  miles  of  gallery  for  the  same  purpose  connected  with  other  mills 
belonging  to  Mr.  Beaumont  in  the  same  district,  and  in  Durham  ;  and  we  learn  from  Mr. 
Sopwith,  that  further  extensions  are  contemplated.  The  value  of  the  lead  thus  saved 
from  being  totally  dissipated  and  dispersed,  and  obtained  from  what  .in  common  parlance 
might  be  called  chimney-sweepings,  considerably  exceeds  £10,(100  sterling  annually,  and 
forms  a  striking  illustration  of  the  importance  of  economizing  our  waste  products. 

In  lieu  of  long  and  extensive  flues,  condensers  of  various  descriptions  have  from  time 
to  lime  been  introduced,  but  in  most  instances  the  former  have  been  found  to  be  more 
ellicii'nt. 

When,  however,  water  can  be  procuv<>dfor  the  purpose  of  cooling  the  condensers,  ex- 
cellent results  are  generally  obtained. — J.  A.  P. 

See  LiTUARGE,  Minicm,  or  Red  Lead,  Solder,  ScG.iR  or  Acetate  of  Lead,  and  White 
Lead. 

LEAD  ORES,  ASSAY  OF.     The  ores  of  lead  may  be  divided  into  two  classes. 

The  first  clans  comprehends  all  the  ores  of  lead  which  contain  neither  sulphur  nor 
arsenic,  or  in  which  they  are  present  in  small  profiortion  only. 

The  .iec(md  class  comprises  galena,  together  with  all  lead  ores  containing  sulphur, 
arsenic,  or  their  acids. 

From  the  facility  with  which  this  metal  is  volatilized  when  strongly  heated,  it  is  neces- 
sary to  conduct  the  assay  of  its  ores  at  a  moderate  temperature. 

A  common  wind-furnace  is  best  adapted  lor  making  lead  assays.  For  this  purpose 
the  cavity  for  the  reception  of  fuel  should  be  9  inches  square,  and  the  height  of  the  flue- 
way  from  the  fire-bars  about  l-l  inclies.  For  ordinary  ores  a  furnace  8  inches  square  and 
12  inches  deep  will  be  found  sufiiciciit ;  l)Ut  as  it  is  easy  to  regulate,  by  a  damper,  the 
heat  of  the  larger  apparatus,  it  is  often  found  advantageous  to  be  able  to  produce  a  high 
temperature. 

A  furnace  of  this  kind  should  be  connected  with  a  chimney  of  at  least  twenty  feet  in 
height,  and  be  supplied  with  good  coke,  broken  into  pieces  of  the  size  of  eggs. 

Ores  of  the  First  Cla.ss. — The  assay  of  ores  of  this  class  is  a  simple  operation,  care 
being  only  required  that  a  sufficient  amount  of  carbonaceous  matter  be  added  to  effect 
the  reduction  of  the  metal,  whilst  such  fluxes  are  supplied  as  will  afford  a  readily-fusible 

slug. 

When  the  sample  has  been  properly  reduced  in  size,  40"  grains  are  weighed  out  and 
well  mixed  with  600  grains  of  carbonate  of  soda,  and  from  40  to  60  grains  of  finely-powder- 
ed charcoal,  according  to  the  richness  of  the  mineral  operated  on. 

This  is  introduced  into  an  earthen  crucible,  of  such  a  .'^ize  as  not  to  be  more  than  one- 
half  filled  bv  the  mixture,  and  on  the  top  is  placed  a  thin  layer  of  common  salt.  The 
crucible  is  then  placed  in  the  furnace  and  gently  heated,  care  being  taken  to  so  moderate 
the  tempi'raturc  that  the  mixture  of  ore  and  flux,  which  soon  begins  to  soften  and  enter 
into  ebullition,  may  not  swell  up  and  flow  over.  If  the  action  in  the  crucible  becomes 
too  strong,  it  must  be  checked  by  removal  from  the  fire,  or  by  a  due  regulation  of  the 
heat  by  means  of  a  damper.  When  the  action  has  subsided,  the  temperature  is  again 
raised  for  a  few  minutes,  and  the  assay  comfilcted.  During  the  process  of  reduction,  the 
heat  shoulil  not  exceed  dull  redness;  but  in  order  to  complete  the  operation,  and  render 
the  slag  sufficiently  liquid,  the  temperature  should  be  r^iiscd  tu  bright  redness. 

When  the  contents  have  been  reduced  to  a  state  of  trancpiil  fusion,  the  crucible  must 
be  removed  from  the  fire  and  the  assay  either  rapidly  poured,  or,  after  being  tapped 
against  some  htird  body  to  collect  the  lead  in  a  single  globule,  be  set  to  cool.  When  the 
operation  has  been  successfully  conducted,  the  cooled  slag  will  present  a  smooth  concave 
surface,  with  a  vitreous  lustre.  When  cold,  the  crucilile  may  be  broken,  and  the  button 
extracted.  To  remove  from  it  the  particles  of  adhering  slag,  it  is  hammered  on  an  anvil, 
and  afterwards  rubbed  with  a  hard  brush. 

Instead  of  employing  carbonate  of  soda  and  powdered  charcoal,  the  ore  may  be  fused 
wi'h  H  times  its  weight  of  black  flux,  and  the  mixture  covered  by  a  thin  layer  of  borax. 

Good  results  are  also  obtained  by  mixing  together  400  grains  of  ore  with  an  equal 
weight  of  carbonate  of  soda  and  half  that  quantity  of  crude  tartar.  These  ingredients, 
after  being  well  incorporated,  are  placed  in  a  crucible,  and  slightly  covered  by  a  layer  of 
borax. 


LEAD  ORES,  ASSAY  OF. 


701 


Each  of  the  foregoing  methods  yields  good  results,  and  affords  slags  retaining  but  a 
small  proportion  of  lead. 

Ores  of  the  Second  Class. — This  class  comprehends  galena,  which  is  the  most 
common  and  abundant  ore  of  lead,  and  also  comprises  sundry  metallurgic  products,  as 
well  as  the  sulphates,  phosphates,  and  arseniates  of  lead. 

Galena. — The  assay  of  this  ore  is  variously  conducted  ;  but  one  of  the  following 
methods  is  usually  employed  for  commercial  purposes. 

Fusion  iciih  an  alkaliJie  fux. — This  operation  is  conducted  in  an  earthen  crucible, 
which  is  to  be  kept  uncovered  until  its  contents  are  reduced  to  a  state  of  perfect  fusion. 

The  powdered  ore,  after  being  mixed  with  three  times  its  weight  of  carbonate  of  soda 
and  10  per  cent,  of  finely  pulverized  charcoal,  is  slowly  heated  in  an  ordinary  assay  fur- 
nace until  the  mixture  has  become  perfectly  liquid,  when  the  pot  is  removed  from  the 
fire,  and.  after  having  been  gently  tapped,  to  collect  any  globules  of  metal  held  in  sus- 
pension in  the  slag,  is  put  aside  to  cool.  When  sufiiciently  cold,  the  crucible  is  broken, 
and  a  button  of  metallic  lead  will  be  found  at  the  bottom :  this  must  be  cleansed  and 
weighed. 

In  place  of  carbonate  of  soda,  pearlash  may  be  employed,  or  the  fusion  may  be  efiFect- 
ed  with  black  flux  alone.  When  the  last-named  substance  is  used,  a  somewhat  longer 
time  is  necessary  for  the  complete  fusion  of  the  assay.  Each  100  parts  of  pure  galena 
will  by  this  method  afford  from  74  to  7t3  parts  of  lead. 

Some  of  the  old  assayers  were  in  the  habit  of  first  driving  off  the  sulphur  by  roasting, 
and  afterwards  reducing  the  resulting  oxide  with  about  its  own  weight  of  black  flux. 

This  method,  from  the  great  fusibility  of  the  compounds  of  lead,  requires  very  care- 
ful management,  and  at  best  the  results  obtained  are  un.satisfactory.  Pure  galena  by  this 
method  can  rarely  be  made  to  yield  more  than  70  per  cent,  of  lead. 

fusion  with  metallic  iron. — Mix  the  ore  to  be  assayed  with  twice  its  weight  of  carbon- 
ate of  soda,  and,  after  having  placed  it  in  an  earthen  crucible,  of  which  it  should  occupy 
about  one  half  the  capacity,  insert  with  their  heads  downward  three  or  four  tenpenny 
nails,  and  press  the  mixture  firmly  around  them.  On  the  top  place  a  thin  layer  of  borax, 
which  should  be  again  covered  with  a  Uttle  common  salt.  The  whole  is  now  introduced 
into  the  furnace  and  gradually  heated  to  redness ;  at  the  expiration  of  ten  minutes  the  tem- 
perature is  increased  to  bright  redness,  when  the  fluxes  will  be  fused  and  present  a  per- 
fectly smooth  surface.  When  this  has  taken  place,  the  pot  is  removed  from  the  fire,  and 
the  nails  are  separately  withdrawn  by  the  use  of  a  small  pair  of  tongs,  care  being  taken  to 
well  cleanse  each  in  the  fluid  slag  until  free  from  adhering  lead.  When  the  nails  have 
been  thus  removed,  the  pot  is  gently  shaken,  to  collect  the  metal  into  one  button,  and 
laid  aside  to  cool ;  after  which  it  may  be  broken,  and  the  button  removed. 

Instead  of  first  allowing  the  slags  to  cool  and  then  breaking  the  crucible,  the  assay 
may,  if  preferred,  after  the  withdrawal  of  the  nails,  be  poured  into  a  mould. 

Assay  in  an  iron  pot. — Instead  of  adding  metallic  iron  to  the  mixture  of  ore  and  flux, 
it  is  generally  better  that  the  pot  itself  should  be  made  of  that  metal. 

For  this  purpose,  a  piece  of  half-inch  plato-iron  is  turned  up  in  the  form  of  a  crucible 
and  carefully  welded  at  the  edges.  The  bottom  is  closed  by  a  thick  iron  rivet,  which  is 
securely  welded  to  the  sides,  and  the  whole  then  finished  on  a  properly  formed  mandril. 
To  make  an  assay  in  a  crucible  of  this  kind,  it  is  first  heated  to  dull  redness,  and,  when 
sufficiently  hot,  the  powdered  ore,  intimately  mixed  with  its  own  weight  of  carbonate  of 
soda,  half  its  weight  of  pearlash,  and  a  quarter  of  its  weight  of  crude  tartar,  is  introduced 
by  means  of  a  copper  scoop.  On  the  top  of  the  whole  is  placed  a  thin  layer  of  borax, 
whilst  the  crucible,  which,  for  the  ready  introduction  of  the  mixture,  has  been  removed 
froiTi  the  fire,  is  at  once  replaced.  The  heat  is  now  raised  to  redness,  the  contents  gradu- 
ally becoming  liquid  and  giving  off  large  quantities  of  gas.  At  the  expiration  of  from 
eight  to  ten  minutes  the  mixture  will  be  in  a  state  of  complete  fusion  ;  the  pot  is  now 
partially  removed  from  the  tire,  and  its  contents  briskly  stirred  with  a  small  iron  rod. 
Any  matter  adhering  to  its  sides  i?  also  scraped  to  the  bottom  of  the  pot,  which,  after  be- 
ing again  placed  in  a  hot  part  of  the  furnace,  is  heated  during  three  or  four  minutes  to 
bright  redness. 

The  crucible  is  then  seized  by  a  strong  pair  of  bent  tongs,  on  that  part  of  the  edge 
which  is  opposite  the  lip,  and  its  contents  rapidly  poured  into  a  cast-iron  mould.  The 
sides  of  the  pot  are  now  carefully  scraped  down  with  a  chisel-edge  bar  of  iron,  and  the 
adhering  particles  of  metallic  lead  added  to  the  portion  first  obtained.  When  sufficiently 
cooled  the  contents  of  the  mould  are  easily  removed,  and  the  button  of  lead  cleaned  and 
weighed.  By  this  process  pure  galena  yields  84  per  cent,  of  metallic  lead,  free  from  any 
injurious  amount  of  iron,  and  perfectly  ductile  and  malleable. 

This  method  of  as.-saying  is  that  adopted  in  almost  all  had-smelting  establishments,  and 
has  the  advantage  of  affording  good  results  with  all  the  ores  belonging  to  the  second 
class. 

Assay  in  the  iron  dish. — In  some  of  the  mining  districts  of  Wales,  the  assay  of  lead 


702 


LEAD,  OXICIILOEIDE  OF. 


ore  is  conducted  in  a  manner  somewhat  different  to  that  just  described.  Instead  of  fusing 
the  ore  in  an  iron  crucible  with  carbonate  of  soda,  pcarlash,  tartar  and  borax,  the  fusion 
is  effected  in  a  flat  iron  dish,  without  the  admixture  of  any  sort  of  flux. — J.  A.  P. 

LEAD,  OXICIILOEIDE  OF.  A  white  pigment  patented  by  Mr.  Hugh  Lee  Tattinson 
of  Newcastle,  which  he  prepares  by  precipitating  a  solution  of  chloride  of  lead  in  hot 
water  with  pure  lime  water,  in  equal  measures;  the  mixture  being  made  with  agitation. 
As  the  operation  of  mixing  the  lime  water,  and  the  solution  of  chloride  of  lead,  require 
to  be  performed  in  an  instantaneous  manner,  the  patentee  prefers  to  employ  for  this  pur- 
pose two  tumbling  boxes  of  about  16  feet  cubic  capacity,  which  are  charged  with  the  two 
liquids,  and  simultaneously  up:  et  into  a  cistern  in  which  oxichloride  of  lead  is  instantane- 
ously formed,  and  from  which  the  mixture  flows  into  other  cisterns,  where  the  oxichloride 
subsides.  This  white  pigment  consists  of  one  atom  of  chloride  of  lead  and  one  atom 
oxide  of  lead,  with  or  without  an  atom  of  water. 

LEATHER,  {t'uir,  Fr. ;  Leder,  Germ. ;  Leer,  Dutch  ;  Lceder,  Danish  ;  Ldder,  Swedish  ; 
Cuojo,  Italian;  Cucro,  Spanish  ;  Kuslia,  Russian.)  This  substance  consists  of  the  skins  of 
animals  chemically  changed  by  the  process  called  tanniiu/.  Throughout  the  civilized 
world,  and  from  the  mo.">t  ancient  times,  this  substance  has  been  cnii>loyed  by  man  for 
a  variety  of  purposes.  Barbarous  and  savage  tribes  use  the  skins  of  beasts  as  skins; 
civilized  man  renders  the  same  substance  unalterable  by  the  external  agents  which  tend 
to  decompose  it  in  its  natural  state,  and  by  a  variety  of  peculiar  manipulations  prepares 
it  for  almost  innumerable  applications. 

Although  the  preparation  of  this  valuable  substance  in  a  rude  manner  has  been  known 
from  the  most  ancient  times,  it  was  not  until  the  end  of  the  last,  and  tlie  beginning  of 
the  present  century  (180(»)  that  it  began  to  be  manufactured  upon  right  principles,  in 
consequence  of  the  researches  of  Macbride,  Deyeux,  Seguin,  and  Davy. 

Skins  may  be  converted  into  leather  either  with  or  without  their  hair  ;  generally,  how- 
ever, the  hair  is  removed. 

The  most  important  and  costly  kinds  are  comprised  under  sole  leather  and  upper  leather, 
to  which  may  be  added  harness  leather,  belts  used  in  machinery,  leather  hose,  &c. ;  but  as 
far  as  the  tanner  is  concerned,  these  are  comprehended  almost  entirely  in  the  kinds  known 
as  upper  leather. 

The  active  principle  by  which  the  skins  of  animals  are  prevented  from  putrefying,  and 
at  the  same  time,  under  some  modes  of  preparation,  rendered  comparatively  impervious  to 
water,  is  called  tannin,  or  tannic  acid,  a  property  found  in  the  bark  of  the  various  .species 
of  Quercus,  but  especially  plentiful  in  the  gall-nut.  When  obtained  pure,  as  it  may  easily 
be  from  the  gall-nut,  by  chemical  means,  tannic  acid  appears  as  a  slightly  yelloiAish,  almost 
a  colorless  mass,  readily  soluble  in.  water ;  it  precipitates  gelatin  from  solution,  forming 
what  has  been  called  tannogelalin.  Tannic  acid  also  precipitates  albumen  and  starch. 
There  can  be  little  difficulty,  after  knowing  the  chemical  combination  just  alluded  to,  in 
understanding  the  peculiar  and  striking  change  produced  on  animal  substance  in  the  forma- 
tion of  leather.  The  hide  or  skin  consists  principally  of  gelatin,  fur  which  the  vegetable 
astringent  tannin  has  an  affinity,  and  the  chemical  union  of  these  substances  in  the  process 
of  taiming  produces  the  useful  article  of  which  we  are  treating. 

Before  entering  upon  the  various  processes  by  which  the  changes  are  effected  on  the 
animal  fibre,  it  may  not  be  uninteresting  to  speak  of  some  of  the  principal  astringents  used 
for  the  purpose  of  producing  these  effects. 

Bark  obtained  from  the  oak-tree  is  the  most  valuable  and  the  most  extensively  used 
ingredient  in  tanning,  and  for  a  long  time  no  other  substance  was  used  in  England  for  the 
purpose.  In  consequence  of  the  demand  having  become  very  much  greater  than  the  sup- 
ply, and  the  consequent  increase  in  the  price  of  the  article,  it  became  necessary  to  investi- 
gate its  properties,  in  order,  if  possible,  to  furnish  the  rcciuired  quantity  of  tanning  matter 
from  other  sources.  Among  other  substitutes  which  wore  tried  with  some  success  in  other 
countries,  may  be  mentioned  heath,  myrtle  Icai'C'!,  viUl  laurel  leajr^,  birch  tree  bark,  and 
(according  to  the  Fciiny  Cyclopadin)  in  1765  oak  sawdust  was  applied  in  England,  and  has 
since  been  used  in  Germany  for  this  purpose. 

Investigation  proved  that  the  tanning  power  of  oak  bark  consisted  in  a  peculiar  astrin- 
gent property,  to  which  the  name  of  tannin  has  been  given,  and  this  discovery  suggested 
that  other  bodies  possessing  this  property  would  be  suitable  substitutes. 

According  to  Sir  II.  Davy,  the  following  proportions  of  tannin  in  the  different  substances 
mentioned  will  be  found : — "  8^  lbs.  of  oak  bark  are  equal  to  2\  lbs.  of  galls,  to  3  lbs.  of 
sumach,  to  7  J  lbs.  of  bark  of  Leicester  willow,  to  11  lbs.  of  the  bark  of  the  Spanish  chest- 
nut, to  18  lbs.  of  elm  bark,  and  to  21  lbs.  of  common  willow  bark." — Penny  Cyclopadin. 

Oak  b.\rk  contains  more  tannin-when  cut  in  spring  by  four  and  a  half  times,  than  when 
cut  in  winter ;  it  is  also  more  plentiful  in  young  trees  than  in  old  ones.  About  40,000 
tons  of  oak  bark  are  said  to  be  imported  into  this  country  annually,  from  the  Netherlands, 
Germany,  and  ports  in  the  Mediterranean.  The  quantity  of  English  oak  bark  used  we  have 
no  means  of  ascertaining.     It  is  prepared  for  use  by  grinding  it  to  a  coarse  powder  between 


LEATHER,  CURRYING  OF. 


703 


cast-iron  cylinders,  and  laid  into  the  tan-pits  alternately  with  the  skins  to  be  tanned.  Some- 
times, however,  as  will  be  hereafter  noticed,  an  infusion  of  the  bark  in  water  is  employed 
with  better  effect. 

Mimosa. — The  bark  and  pods  of  several  kinds  of  Prosopis,  the  astringent  properties  of 
which  have  rendered  them  valuable  in  tanning,  are  known  in  commerce  by  this  name.  The 
Mimosa;  are  a  division  of  the  leguminous  order  of  plants,  which  consists  of  a  large  number 
of  species,  the  Acacia  being  the  principal.  The  sensitive  plants  belong  to  this  division. 
The  proposis  is  found  in  India  and  South  America ;  the  genus  consists  both  of  shrubs  and 
trees. 

Valonia. — The  oak  which  produces  this  acorn  is  the  Quercus  jSyilop^,  or  great  prickly 


S92 


393 


-  97 

-  73 

-  16 

-  14 

The  legumes  of 


cupped  oak,  {figs.  392,  393.)     These  are  exported  from  the  Morea  and  Levant ;  the  husk 
contains  abundance  of  tannin. 

Catechu,  or  Terra  Japomca,  is  the  inspissated  extract  of  the  Acacia  catechu.  At  the 
time  the  sap  is  most  perfectly  formed  the  bark  of  the  plant  is  taken  off,  the  tree  is  then 
felled,  and  the  outer  part  removed ;  the  heart  of  the  tree,  which  is  brown,  is  cut  into 
pieces  and  boiled  in  water ;  when  sufficiently  boiled  it  is  placed  in  the  sun,  and,  subject  to 
various  manipulations,  gradually  dried.  It  is  cut  into  square  pieces,  and  nmeh  resembles  a 
mass  of  earth  in  appearance ;  indeed,  it  was  once  considered  to  be  such,  hence  the  name 
Terra  Japonica. 

We  give  Sir  H.  Davy's  analysis ;  the  first  numbers  represent  Bombay,  the  second  Bengal 
catechu : — 

Tannin 10.9      •         - 

Extractive       -..-...68-- 

Mucilage         -         - 13- 

Impurities       -- 10-- 

This  astringent  is  also  obtained  from  the  Uncaria  Gambir. 

Divinivi  is  a  leguminous  plant  of  the  genus  Ciesalpiuia,  C.  coriaria. 
this  species  are  extremely  astringent, 

and  contain  a  very  large  quantity  of  ^^^ 

tannic  and  gallic  acid ;  they  grow  in 
a  very  peculiar  manner,  and  become 
curiously  curled  as  they  arrive  to  per- 
fection. The  plant  is  a  native  of 
America,  between  the  tropics.  Fig. 
394. 

SnMACn  is  a  plant  belonging  to  the 
genus  Rhus ;  several  of  the  species 
have  astringent  properties  ;  lihus  co'i- 
nus  and  Rhus  coriaria  are  much  used 
in  tanning ;  the  bark  of  the  latter  is 
said  to  be  the  only  ingredient  used  in 
Turkey  for  the  purpose  of  converting 
gelatin  into  leather.    That  used  in  this 

country  is  ground  to  a  fine  powder,  and  is  extensively  applied  to  the  production  of  bright 
leather,  both  l)y  tanners  and  curriers. 

Many  other  vegetable  products  have  been  from  time  to  time  proposed,  and  to  some 
extent  adopted  for  the  same  end,  l)ut  thev  need  not  l)c  enumerated. 

LEATHER,  CURRYING  OF.  The  currici's  .'-hop  has  no  resemblance  to  the  premises 
of  the  tanner,  the  tools  and  manipulations  being  quite  different. 

Within  the  last  twenty  or  thirty  year,'^,  many  tanners  have  added  the  currying  business 


704  LEATHER    CURRYING  OF. 

to  their  establishments,  and  many  curriers  have  likewise  commenced  tanning  ;  but  in  each 
case,  an  extension  of  premises  is  necessary,  and  the  two  departments  are  still  separate. 
The  advantages  derivable  from  this  arrangement  are  twofold, — first,  a  saving  of  time  is 
effected,  for  as  the  tanned  leather  is  sold  by  weight,  it  is  required  to  be  well  dried  belbre 
being  disposed  of  to  the  currier — an  operation  which  is  not  needed  where  the  tanner  carries 
on  the  currying  also ;  and  secondly,  by  the  currier's  art,  the  skins  can  be  reduced  to  a  com- 
paratively uiiitorm  thickness  previous  to  their  being  tanned,  thus  saving  ti)»e  and  bark, 
(used  for  tanning,]  and  insuring  a  more  equal  distribution  of  tannin  through  the  substance 
of  the  skin.  In  the  following  description,  the  business  of  currying  will  be  considered  as 
practised  at  the  present  time  : — 

The  currier's  shop  or  premises,  to  be  convenient,  should  be  spacious.  A  frequent, 
though  not  universal  method,  is  to  have  the  ground-floor  appropriated  to  such  operations  as 
require  the  use  of  a  large  quantity  of  water.  The  place  or  apartment  thus  used,  is  called 
the  scoiiriurf-Iioiise,  and  is  commonly  furnished  with  a  number  of  vatx  or  casks  open  at  one 
end,  in  which  the  leather  is  placed  for  the  purpose  of  soaking,  and  undergoing  such  treat- 
ment as  will  be  hereafter  described.  In  this  apartment  also  is  placed  a  large,  flat,  slate 
stone,  called  a  scouringslone,  or,  more  consistently,  the  stone  on  which  the  leather  is 
scoured.  This  stone,  which  has  its  face  perfectly  flat  and  smooth,  and  which  should  meas- 
ure 8  or  9  feet  in  length,  by  4|  broad,  forms  a  table,  supported  generally  by  masonry,  but 
sometimes  by  a  strong  frame  of  wood,  so  constructed,  that  the  water,  which  is  freely  used 
in  scouring,  may  drain  off  on  the  opposite  side  from  that  on  which  the  workman  is  en- 
gaged ;  an  inclination  of  about  three  or  four  inches  on  the  width  of  the  table  is  sufficient 
for  this  purpose.  Another  piece  of  furniture  very  frequently  found  in,  or  on  Uie  same 
/loor  with  the  scouring-house,  is  a  block  of  sandstone,  in  the  form  of  a  parallelopipedon, 
between  2  and  3  feet  long,  and  9  or  10  inches  broad,  the  upper  face  of  which  is  kept  as 
near  as  possible  a  perfect  plane ;  this  stone  is  fixed  at  a  convenient  height  on  a  strong 
trussel,  and  is  called  the  rub-stone,  because  here  the  workman  rnbs  or  sharpens  his  knives 
and  other  tools.  In  some  large  establishments  where  the  premises  and  water  are  heated  by 
steam,  the  scouring-house  will  be  found  with  a  service  of  pipe  leading  to  the  various  vats, 
and  the  boiler,  for  generating  the  steam,  may  be  conveniently  placed  in  or  near  this  part 
of  the  building. 

The  floor  above  the  scouring-house,  in  the  arrangement  here  laid  down,  is  what  is  spe- 
cially designated  the  shop.     The  furniture  in  this  department  consists  of  a  beam,  (ficj.  295,) 

on  which  the  leather  is  shaved.     It  consists  of  a  heavy 
395  block  of  wood,  on  which  the  workman  stands,  and  into 

one  end  of  which  a  stiff  piece  of  wood  is  firmly  mor- 
tised, at  an  angle  of  about  85° ;  this  upright  (so  called) 
is  about  a  foot  wide,  the  height  being  greater  or  less, 
according  to  the  height  of  the  workman,  each  of  whom 
has  his  beam  adjusted  to  meet  his  convenience.  On 
the  front  of  the  itprirjht,  a  piece  of  deal  is  firmly 
screwed,  to  which  is  glued  a  face  or  plate  of  lignum 
vitcB,  worked  to  j)crrect  smoothness  to  agree  with  the 
edge  of  the  knife  used  in  the  operation  of  shaving. 
It  is  of  the  greatest  importance  to  the  workman,  to 
keep  his  shin  from  injury,  that  his  knife  and  beam 
should  be  kept  in  good  order  A  table  or  tables,  gen- 
erally of  mahogany,  large  planks  of  which  are  used  for 
the  purpose  to  avoid  joints,  may  be  said  to  form  a 
necessary  part  of  the  furniture  of  this  department.  These  tables  are  firmly  fixed,  to  resist 
the  pressure  of  the  workman  when  using  various  tools ;  and  as  light  is  of  the  greatest  con- 
sequence in  the  operations  performed  on  them,  they  are  usually  placed  so  as  to  have  win- 
dows in  front  of  them.  A  high  trussil  is  frequently  used,  across  which  the  leather  is  thrown, 
after  undergoing  any  of  the  processes,  while  the  currier  subjects  other  pieces  to  the  same 
operation. 

Another  part  of  the  premises  is  termed  the  driiing-loff.  In  good  buildings  the  drying- 
loft  is  surrounded  with  veather-boards,  constructed  to  be  opened  or  closed  as  may  be  re- 
quired. The  use  of  this  part  being  the  drying  of  the  leather,  the  ceiling  is  furnished  with 
a  number  of  rails  or  long  pieces  of  wood,  with  hooks  or  nails  on  which  to  hang  the  leather 
for  drying,  and  whore  steam  is  used  for  this  purpose,  the  floor  is  traversed  with  pipes  for 
heating  the  lof:.  Here  also  is  a  table,  similar  to  that  previously  described  ;  it  should  not 
^o,',  be  less  than  7  or  8  feet  long  by  4|  broad,  if  possible, 

—  '  without  joint,  and  with  a  smooth  face. 

)  I    ^^^g^    -  — -=gj ""i^^^^i *  There  are  other  subordinate  departments,   each 

[  ^^~  ~ -°     -    — °     -^P^'^^''     furni.shed  with  a  table  similar  to  those  described. 

\  I  c  Of  the  tools  used  in  currying,  the  knife  stands 

first  in  importance,  (  fig.  39G.)     Here  a  and  b  are  two 
handles  ;  a  is  held  in  the  left  hand,  and  forms  a  powerful  lever  when  the  edge  c  is  !ipj)lied 


LEATHER,  CURRYING  OF. 


705 


to  the  leather.  The  blade  of  the  currier's  knife  is  peculiarly  tempered ;  it  is  composed  of  a 
plate  of  fine  steel,  strongly  riveted  between  two  plates  of  iron.  This  instrument  is  taken 
to  the  rub-stone,  and  ground  to  a  perfectly  sharp  edge  by  successively  rubbing  forward  and 
backward  ;  care  being  taken  to  keep  the  edge  true,  that  is,  straight.  When  this  has  been 
satisfactorily  accomplished,  it  is  still  further  rubbed  on  a  fine  Scotch  or  Welsh  stone  called 
a  clearing-stone,  until  the  scratches  of  the  rub-stoiie  disappear. 

In  this  operation  a  fine  thread  or  wire  forms  on  the  edges,  for  the  knife  has  two  edges 
(<■  c)  which  must  be  carefulily  got  rid  of;  after  which  it  is  wiped  dry,  and  the  edges  greased 
with  tallow  or  oil.  The  workman  then  takes  a  strong  steel,  and  placing  himself  on  his 
knees,  he  fixes  the  knife  with  the  straight  handle  h  against  any  firm  body,  and  the  cross 
handle  a  between  his  knees ;  then  holding  the  steel  in  both  hands  he  carefully  rulis  it  for- 
ward and  backward  the  whole  length  of  the  edge.  During  this  operation  the  knife  is  gradu- 
ally raised  by  means  of  the  handle  a  until  it  is  nearly  perpendicular ;  by  this  means  the 
edge  is  turned  completely  over.  If  the  knife  is  not  well  tempered,  the  edge  thus  obtained 
will  be  irregular,  or  broken ;  in  either  of  which  cases  it  is  of  no  use  whatever. 

To  keep  the  instrument  just  described  in  proper  order  requires  great  skill  on  the 
part  of  the  currier.  The  edge  is  so  delicate  and  liable  to  injury  that  it  cannot  be  used  397 
more  than  a  minute  or  two  without  losing  its  keenness.  To  restore  this,  a  very  care- 
fully  prepared  small  steel  is  used,  fg.  397  ;  the  point  of  the  steel  is  first  run  along 
the  groove  which  is  formed  by  turning  the  edge  over,  and  the  steel  is  then  made  to 
pass  outside  the  edge.  It  is  remarkable  that  a  skillful  hand  can  thus  restore  the  effi- 
ciency of  the  knife,  and  keep  it  in  work  for  hours  without  going  for  a  new  edge  to  the 
rub-stone.     The  other  tools  will  be  described  as  their  uses  are  mentioned. 

The  first  thing  done  by  the  currier  is  the  soaking  of  the  leather  received  from  the 
tanner  in  water ;  the  skin  requires  a  thorough  wetting,  but  not  to  saturation.  In  some  cases 
the  thicker  parts  are  partially  soaked  before  the  immersion  of  the  whole,  and  when  from 
the  nature  of  the  skin  this  cannot  be  done,  water  is  applied  to  the  stout  parts  of  the  dip- 
ping ;  it  is  requisite  that  the  whole  should  be  as  near  as  possible  equally  wet.     In  some 


399 


400 


c^^^'^ 


^Crj:^, 


^S^^i^^^M^ 


instances  the  wetted  leather  is  beaten,  and  sometimes  a  coarse  grainingboard  (hereafter  to 
be  described)  is  used,  to  make  it  more  supple  previous  to  shaving  it.     The  skin  is  then  laid 
over  the  beam,  {fg.  399,)  and  the  rough  fleshy  portion  is  Bliaved  off.     This  operation  is 
Vol.  III. — 15 


T06  LEATHER,  CURRYING  OF. 

generally  called  skiving.  In  all  the  operations  at  the  beam,  the  leather  is  kept  in  its  place 
by  pressure  of  the  knees  or  body  of  the  workman  from  behind.  In  skiving,  the  right  hand 
handle  of  the  knife  somewhat  precedes  the  left,  but  in  shaving,  properly  so  called,  the  kit 
hand  precedes  the  right,  fig.  400.  In  skiving,  the  knife  is  Oriven  obliquely  a  few  inches  at 
a  time  ;  in  shaving,  it  is  driven  with  great  force,  not  unfrequently  from  the  top  to  the  bot- 
tom of  the  beam  ;  great  skill  is  requisite  in  the  performance  of  these  operations,  to  guide 
the  knife  and  to  keep  its  edge.  The  carpenter's  plane  can  be  most  completely  regulated  by 
the  projection  of  the  plane-iron  from  the  wood,  but  the  currier's  knife  admits  of  no  such 
arrangement,  and  the  unskilful  currier  is  constantly  liable  to  injure  the  leather  by  cutting 
through  it,  as  well  as  by  failing  to  produce  a  regular  substance.  The  kind  of  skin,  and  the 
use  for  which  it  is  designed,  will  regulate  the  work  at  the  beam.  In  some  cases,  as  in  tlie 
calf-skin,  it  is  skived  and  then  shaved,  or  (as  it  is  called)  fattened  at  right  angles  to  the 
skiving — in  other  kinds,  as  the  cow-hide  prepared  for  the  upper  leather  of  heavy  shoes, 
after  skiving  it  is  shaved  acvo.'is,  {i.  e.  nearly  at  right  anglea  to  the  skiving,)  and  flattened 
by  being  again  shaved  in  the  same  direction  as  the  skiving.  In  some  manufactories  there 
are  certain  kinds  of  leather  which  are  subjected  to  the  operation  called  by  curriers  stoning, 
before  fattening  :  this  is  done  by  forcibly  driving  the  stock-stone  {Jig.  401)  over  the  grain 

401  402 


side  of  the  leather,  thereby  stretching  it  and  rendering  the  grain  smooth.  The  fattening 
process  is  considerably  facilitated  by  this  stoning,  and  if  the  skin  has  been  allowed  slightly 
to  harden  by  exposure  to  air,  and  the  edge  of  the  knife  is  fine,  as  it  should  be,  the  work- 
man has  but  to  strike  the  flat  part  of  the  knife  over  the  leather  after  the  shaving  is  per- 
formed, to  produce  a  beautiful  face  to  the  flesh  side  of  the  skin.  It  will  not  be  difficult  to 
understand  that  a  good  hand  is  easily  distinguished  from  an  inferior  one  in  this  part  of  the 
business.  With  such  nicety  will  a  skilful  workman  set  the  edge  of  his  knife,  that  although 
there  seems  nothing  to  guide  him,  he  can  take  shaving  after  shaving  from  the  hide,  extend- 
ing from  the  top  to  the  bottom  of  the  beam,  thus  rendering  the  leather  extremely  even  in 
its  substance. 

After  the  process  of  shaving  is  completed,  the  leather  is  placed  in  water,  where  it 
remains  until  it  is  convenient  to  carry  on  the  operation  next  required.  It  is  to  be  observed,' 
that  in  the  condition  in  which  leather  is  shaved,  it  cannot  long  be  kept  without  becoming 
heated  ;  when,  however,  it  is  i)ut  into  water,  it  is  safe  from  injury,  and  may  be  kept  a  very 
long  time,  provided  the  water  be  occasionally  changed  for  a  fresh,  sweet  supply  ;  stale  water 
is  regarded  as  injurious  for  the  skin  to  remain  in. 

Scouring  is  next  proceeded  with ;  the  skin  is  taken  out  of  the  water,  and  laid  on  the 
scouring-stone.  In  respectable  manufactories,  it  is  usual  first  to  scovr  on  the  fesh  ;  this  is 
done  by  passing  a  slicker  smartly  over  the  flesh  side,  by  which  the  grain  of  the  leather  is 
brought  into  close  contact  with  the  scouring-stone,  and,  being  in  a  wet  condition,  the  air  is 
easily  excluded,  so  that  the  leather  sticks  to  the  stone.  A  plentiful  supply  of  water  is  now 
applied,  and  a  large  brush,  with  stiff  hairs,  is  rubbed  over  the  flesh,  or  upper  side.  Por- 
tions of  the  surface,  in  a  pulpy  condition,  come  off  with  the  scrubbing,  and  the  skin  pre- 
sents a  soft,  whitened,  pulpy  appearance ;  the  pores  are  rendered  capable  of  containing 
more  moisture,  and,  altogether,  the  leather  is  much  benefited.  The  slicker  is  a  plate  of 
iron  or  steel,  or  for  particular  purposes,  of  brass  or  copper ;  it  is  about  five  inches  long, 
and,  like  the  stock-stone,  is  fixed  in  a  stock,  or  handle,  {fig.  402.)  It  is  sharpened  at  the 
rub-stone,  by  grinding  the  plate  perpendicularly,  and  then  on  either  side,  thus  producing 
two  edges,  (or  rather,  right  angles.)  The  edges  thus  produced  are  not  of  an  order  to  cut 
the  leather,  but  rather  to  scrape  it.  The  slicker  is  not  intended  to  remove  irregularities  in 
the  leather,  but  its  uses  are  various,  and  it  may  be  considered  a  very  in:portant  tool,  as  will 
hereafter  appear. 

In  the  process  of  tanning,  the  grain  side  of  the  hide  or  skin  becomes  covered  with  a 
whitish  body,  derived  from  the  bark  called  bloom ;  this  is  more  or  less  difficult  to  remove, 
according  to  the  hardness  or  softness  of  the  water  used  in  tanning,  and  the  peculiar  treat- 
ment of  the  tanner.  It  is,  however,  the  currier's  business  to  remove  it,  which  he  effects 
thus : — In  the  case  of  leather,  whose  grain  is  tender,  as  cordovan,  which  is  manufactured 
from  horse  hides,  the  grain  being  kept  uppcnnost,  the  leather  is  spread  on  the  scouring- 
stone,  and  being  plentifully  supplied  with  water,  is  stretched  by  using  the  slicker,  or  a  fine 
pebble,  ground  to  the  shape  of  the  stock-stone  the  bloom  ;  is  thus  loosened,  and,  at  the  same 
time,  by  making  it  adhere  to  the  scouring-stone,  the  next  operation  is  readily  carried  on, 
which  consists  in  smartly  brushing  the  grain  with  a  stiffhaired  brush,  at  the  same  time  keep- 
ing a  quantity  of  water  on  the  surface,  flie  slicker  is  again  used  to  remove  the  water  and 


LEATHER,  CURRYING  OF.  707 

loosened  bloom,  and  the  scouring  is  complete.  In  the  scouring  of  calf-skins,  and  cow  or 
ox  hides,  the  stock-stone  is  used  to  fix  the  leather,  and  a  piece  of  pumice-stone,  the  face  of 
which  has  been  ground  to  smoothness,  and  afterwards  cut  in  grooves,  is  then  forcibly  rubbed 
over  the  grain,  in  order  to  remove  the  bloom.  In  this,  as  in  other  operations  on  the  scour- 
ing-stone,  water  is  a  necessary  ingredient.  The  bloom  being  sufficiently  loosened  by  the 
pumice-stone,  the  brush  is  used  to  scrub  up  the  remaining  dirt,  which  is  then  removed  by 
the  stock-stone  or  slicker.  In  harness  leather,  which  is  stout,  and  requires  to  be  stretched 
as  much  as  possible,  the  pumice-stone  is  seldom  used,  the  stock-stone  and  scouring-orush 
being  lustily  applied  until  the  bloom  is  sufficiently  removed.  Ordinary  manufacturers  within 
the  present  (nineteenth)  century,  have  considered  the  operations  of  the  scourmg-honse  com- 
plete at  this  point.  The  modern  currier  takes  a  different  view,  and  not  unfrequently  detains 
his  scoured  property  for  days,  and  sometimes  for  weeks,  in  the  scouring-house. 

If  the  leather  is  imperfectly  tanned,  or  it  is  required  to  be  made  of  a  bright  color,  there 
are  other  processes  to  be  passed  through.  In  these  cases  sumach  (an  evergreen  shrub  of 
the  natural^rder  Anacardiacece,  genus  Ukus,  and  from  the  bark  of  which  all  the  leather 
made  in  Turkey  is  said  to  be  tanned)  is  infused  in  boiling  water,  and  when  cooled  to  a  tepid 
state  the  leather  is  placed  in  it.  After  staying  a  sufficient  time  it  is  taken  to  the  scouring- 
stone  ;  if  cordovan,  it  is  slicked  as  dry  as  can  be  well  accomplished  on  the  Jlesh  side  ;  other 
leather  is  for  the  most  part  slicked  in  a  similar  way  on  the  grain  side.  Saddle  leather  which 
is  required  to  be  of  a  bright  color  is  still  farther  placed  in  warm  water  slightly  acidulated 
with  sulphuric  or  oxalic  acid,  or-  both  ;  here  for  a  time  it  is  kept  in  motion,  then  taken  to 
the  scouring-stone,  it  is  washed  with  peculiar  chemical  lotions,  according  to  the  taste  or 
knowledge  of  the  workman  ;  then  again  it  is  dipped  in  tepid  sumach  infusion,  then  slicked 
with  a  copper  or  brass  slicker,  (iron  is  liable  to  stain  leather  thus  prepared,)  and  a  thin  coat 
of  oil  being  applied  to  either  side,,  it  is  removed  to  the  drying-loft.  Until  within  a  very 
few  years,  much  time  and  trouble  were  taken  to  produce  very  bright  leather  for  the  sad- 
dler ;  but  of  late,  brown-colored  leather  has  been  adopted  to  a  considerable  extent,  as  it  is 
less  liable  to  become  soiled.  Nearly  all  leather  is  placed  a  short  time  in  the  loft  before  far- 
ther manipulations  are  carried  on,  in  order  to  harden  it  slightly  by  drying. 

In  the  drying-loft,  or  its  immediate  vicinity,  the  leather  receives  the  dubbing  (daubing, 
probably)  or  stuffing.  The  substance  so  called  is  composed  of  tallow  brought  to  a  soft 
plastic  condition  by  being  melted  and  mixed  with  cod-liver  oil ;  occasionally  sod  (an  oil 
made  in  preparing  sheep-skins)  is  in  very  small  quantities  added  to  the  mixture.  This  is 
laid  upon  the  leather  either  with  a  soft-haired  brush,  or  a  mop  made  generally  of  rags. 

The  leather  is  prepared  for  stuffing  by  wetting  slightly  such  parts  as  have  become  too 
dry.  It  is  then  taken  to  the  table  previously  described,  which  being  slightly  oiled,  the  pro- 
cess is  carried  on  by  placing  the  skin  on  the  table  in  the  manner  most  convenient  for  stretch- 
ing it  and  making  the  surface  smooth.  In  those  kinds  that  have  a  rough  wrinkled  grain,  the 
flesh  side  is  placed  next  the  table  and  tlie  stock-stone  is  used  very  smartly  to  stretch  and 
smooth  the  grain.  A  kind  of  clamp  or  holdfast,  composed  of  two  checks  fastened  with  a 
screw,  is  sometimes  used  to  prevent  the  leather  from  moving  during  this  operation,  but  in 
general  these  are  not  required ;  the  slicker  is  then  applied  to  remove  the  marks  left  by  the 
stock-stone,  and  a  thin  stuffing  being  spread  over  the  grain,  it  is  turned  over,  slicked  on  the 
flesh  lightly,  a  coat  of  stuffing  is  sjiread  over  it,  and  it  is  hung  up  to  dry.  In  those  kinds 
which  have  to  be  blacked  (or  stained)  on  the  grain,  a  little  cod  oil  only  is  spread  on  the 
grain,  and  the  slicker  is  applied  on  the  flesh  side  most  laboriously  previous  to  stiffing. 
Much  skill  is  required  to  give  the  requisite  quantity  of  stuffi  (dubbing)  to  the  leather  with- 
out excess,  excess  being  injurious,  and  the  quantity  required  is  farther  regulated  by  the 
freshness  or  otherwise  of  the  leather,  the  tan-yard  from  which  it  comes,  and  the  treatment 
it  has  received  in  the  scouring-house. 

When  dry,  the  skins  or  hides  are  folded  together,  to  remain  until  required.  It  is  cer- 
tain the  leather  improves  by  remaining  some  weeks  in  this  condition.  It  should  be  ob- 
served that,  in  drying,  the  leather  absorbs  a  large  quantity  of  the  oleaginous  matter  with 
which  it  is  charged,  and  the  unabsorbed  portion  forms  a  thick  coating  of  hardened  greasy 
matter  on  the  flesh  side. 

Leather  which  has  to  be  blackened  on  the  flesh,  (uux  leather,)  from  this  point,  receives 
different  treatment  from  grain  leather.     Wax  leather  is  taken  to  the  shop-table  and  softened 

403 


'-^^. 


'^~^'«^A/^A^A;^.N»'^-'''^ 


with  a  graining-board.     The  skin  is  laid  on  the  table  and  doubled,  grain  to  grain,  the  grain- 
wi^-board,  {fig.  404,)  which  is  confined  to  the  hand  by  a  leather  strap,  (a  a,)  is  driven  for- 


708 


LEATHER,  CUERYING  OF. 


ward  and  drawn  back  alternately  until  a  grain  is  raised  on  the  leather,  and  it  has  attained 
the  required  suppleness.  Observe,  the  graiuing-board  is  slightly  rounded  on  the  lower  sur- 
face, aiid  traversed  by  parallel  grooves  from  side  to  side,  which  are  coarser  or  finer,  as  occa- 
sion reiiuires.  The  grease  is  next  removed  from  tlie  flesh  by  the  slicker,  and  afterwards  a 
sharp  s.icker  is  passed  over  the  grain  to  remove  grease  or  other  accumulations  from  it.  The 
next  process  is  called  nfiiteniiiff.  The  leather  is  laid  over  the  bccan,  and  a  knife  with  an 
extremely  fine  edge  is  used  to  take  a  thin  shaving  from  the  flesh  side ;  this  is  a  point  at 
which  a  currier's  sldll  is  tested.  The  knife  used  is  one  that  has  been  very  much  worn,  the 
quality  of  which  has  been  tested  to  the  utmost ;  and  so  extremely  true  is  the  edge  ex- 
pected, that  not  the  slightest  mark  (^^crafc/i)  is  allowed  to  appear  on  the  surface  of  the 
leather.  Only  a  good  workman  can  satisfactorily  accomplish  tliis.  The  slightest  gravel  in 
the  flesh  of  the  skin  may  break  the  edge  of  the  knife  in  pieces,  and  it  is  not  easy  to  rectify 
so  serious  a  misfortune ;  besides,  a  poor  workman  may  tear  up  the  edge  by  steeling,  an 
operation  which  ought  to  mend  the  mischief  instead  of  provoking  it.  ^ 

A  fine  (jrainhiff-board  is  next  used  to  soften  the  leather  ;  the  stiffer  parts  being  boarded 
both  on  the  grain  and  flesh  sides,  and  the  operation  being  carried  on  in  two  or  three  direc- 
tions, to  insure  both  softness  and  regularity  of  grain.  Boarding  is  performed  by  doubling 
the  leather  and  driving  the  double  part  forward  and  drawing  it  backward  by  the  graining- 
board. 

The  leather  is  now  prepared  for  the  waxer,  and  passes,  consequently,  into  his  hands. 
Waxing,  in  large  establishments,  is  a  branch  considered  separate  from  the  general  business, 
and  is  usually  in  the  hands  of  a  person  who  confines  himself  to  this  occupation  alone.  The 
skin  is  laid  on  a  table,  and  the  <;oA)>-  rubbed  into  the  flesh  side  with  a  brush.  It  is  necessary 
to  give  the  brush  a  kind  of  circular  motion  to  insure  the  rec)uired  blackness  in  the  leather. 
The  rii/or  'S  made  by  stirring  a  quantity  of  the  best  lampblack  into  cod-liver  oil  ;  sometimes 
a  little  dubbing  is  added,  and  in  order  to  make  it  work  smoothly  so  as  not  to  clog  the  brush, 
some  stale  tan-water  from  the  vats  in  the  scouring-house  is  beaten  vp  with  the  mixture  until 
it  combines  therewith.  The  preparation  of  the  color  is  an  important  affair,  and  requires  i 
considerable  amount  of  time  and  labor  to  render  it  such  as  the  ivaxcr  desires. 

A  .ilick-sfone,  or  gtasx,  is  next  used  ;  this  tool  is  aliout  the  size  and  shape  of  the  slicker, 
but  instead  of  being  ground  like  it,  the  edges  are  very  carefully  removed,  so  that  while, 
fr(jin  end  to  end,  it  preserves  nearly  a  right  line,  it  is  circular  across  the  edge.  The  stone 
(a  fine  pebble)  is  little  used  now,  plate-glass  being  substituted  for  it.  The  use  of  the  tool 
just  described  is  to  smooth  the  flesh  after  the  operation  by  the  coloring  brush,  thereby  get- 
ting rid  of  any  marks  made  on  the  surface. 

The  next  step  in  waxing  is  what  is  called  sizing.  Size  is  prepared  by  boiling  glue  in 
water — the  melted  glue  is  diluted  with  water  to  the  extent  required — in  some  cases  it  is 
softened  by  mixing  cod-liver  oil  with  it  in  cooling.  When  cold,  it  is  beaten  up  with  various 
ingredients,  according  to  the  taste  or  experience  of  the  waxer  ;  the  waxer  then  well  rubs 
the  size  into  the  colored  side  of  the  leather,  and  with  a  sponge,  or,  more  generally,  the 
fleshy  part  of  his  hand,  smooths  it  off.  When  dry,  the  slick-stone,  or  glass,  is  again  ap- 
plied, thus  producing  a  polish  on  the  size  ;  and  a  very  thin  coat  of  oil  completes  the  work. 
In  ditfereiit  manufactories  different  methods  are  pursued,  but  the  above  is  convenient  and 
satisfactory  in  almost  all  circumstances.     It  is  now  ready  for  the  shoemaker. 

Leather  intended  to  be  blacked  on  the  grain,  is  lelt  folded  up  when  dry  after  stuffing. 
Some  years  ago  it  was  the  custom  to  stain  these  kinds  of  leatlior,  while  wet  in  the  scouring- 
house,  by  spreading  stale  urine  over  it  and  then  applying  a  solution  of  copjieras,  (sulphate 
of  iron.)  That  method  is  now  exploded.  The  dry  skins  or  pieces  of  leather  are  laid  on 
the  shop-board  :  a  brush  is  used  to  saturate  the  graiii  with  urine,  or  as  is  now  more  com- 
mon, a  solution,  of  soda  in  water,  and  a  peculiar  preparation  of  iron  in  solution  is  afterwards 
laid  over  it,  which  blackens  the  surface.  It  may  be  observed  that  in  wax-leather  a  body  of 
black  is  laid  on,  and  rubbed  into  the  flesh  ;  in  grain  leather  the  black  is  a  stain.  After  the 
blackening,  it  is  necessary  to  rub  a  small  quantity  of  oil  or  dubbing  over  the  blackened  sur- 
face, then  turning  the  oiled  grain  towards  the  table,  a  sharp  slicker  is  used  on  the  flesh  side ; 
the  leather  sticks  to  the  table  by  means  of  the  oil,  and  the  slicker  is  driven  so  smartly  ovtr 
it,  that  it  is  stretched  on  the  table,  at  the  same  time  that  the  grease  is  removed.  It  is  quite 
an  imj)ortant  point  to  take  all  the  stretch  out  of  the  leather  in  this  operation,  after  which  it 
is  turned  over ;  the  table  is  covered  with  a  very  thin  coat  of  liard  tallow,  a  roll  of  tallow 
being  rubbed  over  the  table,  for  the  purpose  of  keeping  the  leather  fastened  to  it.  A  dull 
.slicker  is  used  on  the  grain  to  remove  remaining  marks  and  wrinkh^s,  or  to  smooth  any 
coarse  appearance  on  the  grain  ;  a  sharp  slicker  removes  all  the  grease,  and  a  thin  coat  of 
weak  size,  made  of  glue  dissolved  in  water,  is  spread  over  it,  and  the  process,  usually  called 
seasoninfi,  is  completed.  The  next  object  is  carefully  to  dry  the  seasoned  leather,  and  in 
this  state  it  may  be  .stored  without  injury. 

The  next  step  is  very  similar  to  that  described  in  the  case  of  vax-leather,  and  called 
whitening  : — it  is  then  softened  by  means  of  a  fine  graining-board,  or  a  board  of  the  same 
shape  and  size  covered  with  cork,  the  grain  side  is  placed  next  the  table,  and  the  flesh 


LEATHER,  CURRYIXG  OF. 


709 


doubled  against  the  flesh,  and  thus  driven  forwards  and  backwards  until  the  required  degree 
of  suppleness  is  obtained.  The  loose  particles  of  flesh  are  brushed  off,  and  u  slicker  care- 
fully passed  over  the  grain  removes  all  >h«/-^.<  of  the  last  operation.  If  a  sufficiency  of 
stuff  has  not  been  applied  in  the  drying-loft,  the  deficiency  is  remedied  by  a  coat  of  ta  low- 
dubbing  now  spread  over  the  grain,  and  allowed  to  remain  soaie  l:oars.  As  the  leather 
absorbs  the  oily  matter,  a  hardened  coat  of  grease  has  to  be  removed  by  the  aid  of  the 
slicker.  Tne  leather  is  then  sized,  and  a  very  thin  coat  of  o.l  spread  over  the  size  com- 
pletes the  operation. 

In  the  preparation  of  various  kinds  of  leather,  or  of  leather  for  particular  purposes,  the 
currier  has  particular  appliances.  Harness  leather  is  considerably  dryer  than  o:i;er  kinds 
te'bre  s  uffing,  and  is  subjected  to  immense  labor  by  the  stock-stone  and  slicker,  to  procure 
a  smootu  grai.i.  It  is  blackened  when  dry  like  other  gmin  leather,  but  instead  uf  the  oil- 
ing and  other  processes  described,  the  hardest  tallow  procurable  is  rubbed  into  it,  stoned 
with  a  fine  pebble,  slicked,  and  tallow  again  rubbed  into  it  by  the  hand.  Wuen  dry  after 
this  operation,  the  grease  is  slicked  from  the  flesh  side,  and  a  repetition  of  the  tallowing, 
stoning,  and  rubbing  finishes  the  work. 

Saddle  leather,  which  is  cut  into  comparatively  small  pieces,  after  hardening  in  the  dry- 
ing-loft, is  passed  through  a  very  different  process  from  any  described  previously.  Tlie  skin 
of  the  hog  is  much  used  for  certain  parts  of  hackney  saddles,  and  the  bristles,  when  re- 
moved by  the  tanner,  leave  indentations,  or  even  holes  in  the  tanned  skin.  Probably  it  was 
deemed  desirable  to  obtain  some  imitation  for  the  parts  of  the  saddle  where  the  bog  skin 
was  not  suitable.  The  skin  of  the  dog-fish  (^Scyllium,  Cuv  )  to  some  extent  supplied  the 
imitation,  having  hard  tubercles  on  its  surface.  At  first  the  skin  was  laid  on  the  leather, 
and  lustily  pressed  into  it  by  rubbing  it  with  a  pebble  or  plate  of  glass  ;  at  length  a  press 
was  invented,  and  more  recently  various  methods  have  been  proposed  to  produce  the  best 
effect.     We  have  here  {fig.  405)  a  representation  of  one  of  these  presses,  which  may  stand 


405 


<^e 


e&^ 


--^■= 

E==S=i 

-j==-=~^^^:'--^-     ^ 

.4 

\==^ 

|\ 

^ 

^;t, 

I 

1 

_j 

«k 

\ 


as  a  type  of  all  others ;  a  a  are  the  feet  into  which  the  uprights  are  inserted  ;  b  b  arc  the 
two  upright  sides  tied  at  the  top  by  c  /  a  similar  cross-piece  ties  them  a  little  above  the 
feet ;  </  is  a  leaf  fastened  with  hinges,  which  closes  upon  c  when  the  press  is  not  in  use ; 
e  e  are  screws  which  press  on  the  iron  plate,  in  which  the  axes  of  the  roller  f  are  inserted ; 
these  plates  imbedded  in  the  uprights  b  b  have  considerable  plan,  so  as  to  allow  the  rollers 
f  h  more  or  less  pressure  as  the  case  may  require.  The  dotted  line  i  i',  represents  an  iron 
bar  or  cylinder,  supplied  with  a  small  cog-wheel  at  t,  and  n  craiik-fouidU  j;  this  is  turned 
round  by  the  hatid,  and  the  small  cog-wheel  acts  on  a  larger  one  k,  which  is  attached  to  the 
axis  of  the  roller/;  /  is  a  solid  roller  of  hard  wood,  sucli  as  lignum  vitce;   upon  this 


710 


LEATHER,  CURRYING  OF. 


cylinder  is  strongly  glued  the  J!sk  sJcin,  previously  alluded  to  ;  A  is  a  cylindrical  solid  piece 
of  wood  covered  with  stout  flannel ;  Ms  a  piece  of  leather  on  which  the  leather  to  be 
pressed  is  placed ;  when  all  is  adjusted,  the  piece  to  be  pressed  is  placed  on  I,  the  handle  is 
moved  slowly  round,  and  the  whole  is  carried  between  the  rollers ;  the  leather  thus  receives 
the  imprint  of  the  Jish  skin,  and  at  the  same  time  becomes  extremely  solid.  After  drying, 
this  is  tit  for.  the  saddler. 

Of  late  years  the  currier  has  undertaken  an  office  which  was  previously  the  business  of 
the  boot-maker — namely,  the  blocking  of  boot  fronts.  This  is  performed  by  the  instrument 
represented  by  Jig.  406.     The  leather  is  first  dressed,  as  previously  described,  up  to  the 

406 


point  of  being  ready  for  v;hitening.  The  fronts  are  then  cut,  {Jig.  406  a,)  and  when  folded 
or  doubled  appear  as  Jig.  406  b.  V  1',  1  1,  is  a  strong  framework  ;  2,  represents  a  pair  of 
cheeks,  strongly  fastened  in  the  frame,  and  regulated  as  to  distance  by  a  screw ;  these 
cheeks  are  lined  with  zinc ;  3  is  a  strong  plate  of  metal,  the  angle  at  3  corresponding  ex- 
actly with  the  angle  of  the  cheeks  ;  the  ends  of  this  plate  are  fixed  in  movable  plates  pass- 
ing down  the  columns  1'  1';  4  is  a  handle  by  which  the  instrument  is  worked,  and  which  by 
cog-wheels  acting  on  the  movable  plates  brings  3  downwards.  The  front,  a,  is  laid,  after  a 
thorough  soaking  in  water,  over  the  cheeks  2,  the  handle  being  turned,  3  comes  down  upon 
the  front,  and  forces  it  through  the  small  opening  between  the  cheeks,  and  when  brought 
out  below  the  cheeks,  it  has  the  appearance  here  given,  {Jig.  406  c.)  The  plate  3  having 
carried  the  front  between  the  cheeks,  is  removed,  {belou;)  and  the  weight  5  assists  in  bring- 
ing the  perpendicular  movable  plates  to  their  place,  when  3  is  again  put  in  position  ;  and 
thus  the  operation  is  rapidly  carried  en.     After  this  the  fronts  are  regularly  placed  on  a 


LEATHER,  VEGETABLE. 


711 


block,  being  forced  into  position  by  an  instrument  called  the  Jloiinder,   {fig.  407,)  and 
tacked  to  their  place  ;  after  this  they  are  slightly  oiled  and  dried.     Some  ingenious  methods 

407 


have  been  adopted  for  softening  the  fronts,  so  as  not  to  disturb  the  blocking.     They  are 
whitened  on  a  very  sloping  beam,  {Jig.  408,)  which  enables  the  workman  to  hold  them  bet- 


408 


ter  than  he  could  on  the  common  beam.  They  are  again  blocked  by  the  waxer,  and  when 
these  processes  are  carefully  performed,  much  trouble  is  saved  to  the  boot-maker.  Of 
course,  in  a  manufactory  many  appliances  are  found  which  are  not  here  mentioned  ;  the  gen- 
eral idea,  however,  may  be  easily  gathered  from  this  description.  The  work  is  dirty  and 
very  laborious,  requiring  great  skill  and  experience,  and  consequently  good  workmen  have 
generally  commanded  better  wages  than  other  mechanics. 

Hides  intended  for  covering  coaches  are  shaved  as  thin  as  shoe  hides,  and  blacked  on 
the  grain. — H.  M. 

LEATHER,  VEGETABLE.  Under  this  name  a  new  material,  composed  of  india-rub- 
ber spread  upon  linen,  has  been  introduced.  Of  this  the  Mechanics^  Magazine  writes ; — 
"  Having  seen  some  specimens  of  these  leathers,  as  well  as  various  articles  of  utility  manu- 
factured therewith,  we  have  been  induced  to  pay  the  extensive  works  of  Messrs.  Spill  &  Co., 
the  eminent  Government  contractors,  on  Stepney-green,  a  visit,  in  order  to  cull  sufficient  to 
place  upon  record  the  present  position  of  artificial  as  a  substitute  for  real  leather.  The  face 
and  general  character  of  the  vegetable  leather  resemble  the  natural  product  so  closely,  that 


712  LENS. 

it  is  only  by  actual  examination  that  the  difference  can  be  determined.  This  is  more  par- 
ticularly the  case  in  that  description  which  is  made  for  bookbinding,  the  covering  of  library 
tables,  and  like  purposes.  Amongst  other  advantages  it  possesses  over  leather  proper,  may 
be  mentioned,  that  however  thin  the  imitation  is,  it  will  not  tear  without  considerable  force 
is  exercised ;  that  it  resists  all  damp,  and  that  moisture  may  be  left  upon  it  for  any  period 
without  injury,  consequently,  it  does  not  sodden  or  cockle,  is  always  dry,  and  its  polish  is 
rather  increased  than  diminished  by  friction.  Add  to  these  facts,  that  any  attempt  to 
scratch  or  raise  its  surface  with  the  nail,  or  by  contact  with  any  ordinary  substance,  will 
not  abrade  it,  and  enough  will  have  been  Siiid  to  justify  its  entering  the  list  against  an  article 
of  daily  use,  which  has  of  late  years  been  deemed  far  from  sufficient  for  the  demand,  and 
has  consequently  risen  in  price  to  the  manifest  loss  and  injury  of  every  class  of  the  commu- 
nity. We  believe  that  the  largest  entire  piece  of  real  leather  that  can  be  cut  from  a  bul- 
lock's hide,  is  not  more  than  7  feet  by  5  feet,  and  this  includes  the  stomach  and  other 
inferior  parts.  Vegetable  leather,  on  the  contrary,  is  now  produced  EO  yards  in  length, 
and  H  yards  wide,  every  portion  being  of  equal  and  of  any  rc()uircd  thickness,  and  the 
smallest  portion  is  convertible.  We  were  agreeably  dit^ajipointed,  liowever,  to  find  that 
instead  of  vegetable  leather  being  a  discovery  requiring  the  aid  of  oUi  selves  and  contempo- 
raries, it  was,  although  so  young,  an  active  agent  in  the  fabrication  of  numerous  articles  of 
daily  requirement,  and  that  it  had  already  become  the  subject  of  large,  indeed  we  may  say 
enormous,  contracts.  Caoutchouc  and  naphtha  are  used  in  its  manufactuie;  but  by  a 
process  known  to  the  senior  of  the  firm,  who  is  himself  an  accomplished  chemist,  all  odor 
is  removed  from  the  naphtha,  and  the  smell  of  vegetable  leather  is  rendered  thereby  less  in 
strength,  if  any  thing,  than  that  of  leather.  The  principal  objects  to  which  it  is  at  present 
applied,  although  it  is  obvious  it  will  take  a  wider  range  of  usefulness  than  leather  itself, 
are  carriage  and  horse  aprons,  antigropola,  soldiers'  belts,  buckets  which  pack  flat,  harness 
of  every  description,  bookbinding,  &c.  For  the  latter,  its  toughness,  washable  quality,  and 
resistance  to  stains,  render  it  remarkably  fitted.  Its  thickness,  which  may  be  carried  to 
any  extent,  is  obtained  by  additional  backings  of  linen,  &c.,  cemented  with  the  caoutchouc, 
and  its  strength  is  something  marvellous,  while  in  the  all-important  commercial  view,  it  is 
but  one-third  the  price  of  leather.  Many  of  the  articles  we  were  shown  possessed  the  ap- 
pearance of  much  elegance  and  finish ;  but  it  was  curious  to  observe,  that  although  most  of 
them  could  be  made  without  a  stitch,  and  within  the  factory  itself,  a  deference  to  the  feel- 
ings of  the  workmen  in  the  several  trades  has  been  shown  by  the  fiim,  and  the  material  is 
given  out  as  ordinary  leather,  to  undergo  the  process  of  the  needle,  which  it  submits  to 
with  a  greater  facility  than  its  original  prototype." 

LENS.  {Lentille,  Fr. ;  Linsenglas^  Germ.)  Lenses  are  transparent  bodies,  usually 
made  of  glass,  which  by  their  curvature  either  concentrate  or  disperse  the  i  ays  of  light. 
Lenses  are  of  the  following  kinds: — Double  convex^  having  the  same  or  a  different  degree  of 
convexity  on  either  side.  Pla)io-convex,  having  one  plane  and  one  convex  surface.  Coit- 
cai'o-convcx,  having  one  concave  and  one  convex  side,  commonly  called  tnciiiscus  lenses. 
Plano-concave,  having  one  plane  surface  and  one  concave  one ;  and  the  double  concave 
lens. 

The  first  three,  which  are  thicker  in  the  middle  than  at  the  edge,  are  converc/inff  lenses^, 
because  they  occasion  the  rays  of  light  to  converge  in  passing  through  them.  The  others, 
which  are  thicker  at  the  edges  than  in  the  middle,  and  therefore  cause  the  pencils  of  light 
refracted  through  them  to  diverge,  are  called  diverging  lenses. 

For  the  most  complete  examination  of  the  laws  regulating  the  construction  of  lenses, 
and  the  action  of  these  on  the  rays  of  light,  we  must  refer  the  reader  to  Sir  John  Herschcl's 
admirable  treatise  on  Lic/ht  in  the  Encyclopedia  Mtiioj olitana.  In  this  work  we  have 
only  to  deal  with  the  mode  of  manufacturing  the  ordinal  y  vaiieties.  The  spherical  surfaces 
are  produced  by  grinding  them  in  counterpart  tools,  or  discs  of  metal,  prepared  to  the  same 
curvature  as  the  lenses.  For  the  formation  of  the  grinding  tools,  a  concave  and  a  convex 
template  are  first  made  to  the  radius  of  the  curvature  of  the  required  lens.  The  templates 
of  large  radius  are  sometimes  cut  out  of  crown  glass.  More  usually  the  templates  are  made 
out  of  sheet  brass ;  the  templates  of  long  radii  are  cut  with  a  strong  radius  bar  and  cutter, 
and  those  of  only  a  few  inches  radius  are  cut  in  the  turning  lathe.  The  brass  concave  and 
convex  gauges  are  cut  at  separate  operations,  as  it  is  necessary  to  adjust  the  radius  to  com- 
pensate for  the  thickness  of  the  cutter,  and  the  brass  templates  are  not  usually  corrected  by 
grinding,  as  practically  it  is  found  more  convenient  to  fit  the  tools  themselves  together. 
The  templates  having  been  made  of  the  required  radius,  are  used  for  the  preparation  of  the 
grinding  and  polishing  tools,  which  for  concave  Jenses  consist  of  a  concave  rough  grinding 
tool  of  cast  iron  called  a  i^hell. 

A  pair  of  brass  tools  is,  however,  the  most  important  part  of  the  apparatus.  One  of 
these  is  concave  and  the  other  convex,  made  exactly  to  the  curvature  of  the  templates,  and 
to  fit  each  other  as  accurately  as  possible.  The  concave  tool  is  used  as  the  grinder  for  cor- 
recting the  curvature  of  the  lenses  after  they  have  been  roughly  figured  in  the  concave 
shell,  dtnd  the  convex  tool  is  employed  for  producing  and  maintaining  the  true  form  of  the 


LEXS. 


713 


409 


i^'iir^ 


41'> 


concave  grinding  tool  itself,  and  also  that  of  the  polisher.  These  polishers  are  adjustod 
with  great  accuracr.  The  concave  tool  is  placed  upon  the  convex,  and  thev  are  first  rubbed 
tcgnher  dry,  so  that  by  the  brightened  parts  the  inequalities  may  be  distinguished;  they 
are  then  ground  true,  first  by  means  of  emery  and  water,  and  tlien  with  dry  emery. 

The  following  figure  (409)  represents  those  tools,  which  are  fitted  with  screws  at  the 
back  so  that  they  can  be  fixed  upon  pillars  in  connection  with 
the  machinery  for  giving  motion  to  them. 

By  grinding  with  sundry  niceties  of  motion  which  are  re- 
quired to  produce  the  best  eftect,  such  as  the  production  of  mo- 
tion which  shall  resemble  as  nearly  as  possible  the  kind  of  stroke 
which  would  be  given  by  the  hand,  these  tools  are  eventually 
brought  to  true  spherical  figures  which  fit  each  other  exactly. 

The  glasses  for  lenses  being  selected  of  suitable  quality,  they 

are  brought  to  a  circular  form  by  means  of  flat  pliers  called     \^         -^^^    ^ 

shanks.  The  pressure  of  the  pliers,  applied  near  the  edges  of 
the  glass,  causes  it  to  crumble  away  in  small  fragments,  and  this 
process,  which  is  called  shankinrj  or  nibbling,  is  continued  until 
fie  ghisscs  are  made  circular,  and  of  a  little  larger  diameter  than 
tlie  finished  size  of  the  lenses. 

A  cement  is  made  by  mixing  wood  ashes  with  melted  pitch.  Some  nicety  is  required 
in  the  adjustment  of  the  proportion,  since  the  cement  must  not  be  too  adhesive,  nor  must  it 
hi  too  hard  or  too  brittle :  generally  about  4  lbs.  of  wood  ashes  to  14  lbs.  of  pitch  are  em- 
ployed. This  when  melted  is  poured  on  one  side  of  the  glasses  to  be  ground,  in  small 
quantities  at  a  time,  until  a  sufficient  quantity  adheres  to  the  back  of  the  lens  to  form  a 
liandl2.  The  glass  is  rough  ground  by  rubbing  it  within  the  spherical  shell.  The  glass  is 
niljbed  with  large  circular  strokes,  and  the  shell  is  usually  placed  within  a  shallow  tray  to 
catch  the  loose  emery  or  polishing  powder  which  may  be  employed.  When  one  side  is 
rough  ground  in  this  way,  the  glass  is  warmed  to  detach  it  from  the  handle,  which  is  trans- 
ferred to  the  other  side  and  the  operation  repeated.  When  both  sides  are  thus  rudely 
formed,  the  lenses  are  cemented  upon  a  runner.  The  best  object-glasses  for  telescopes  are 
ground  and  polished  singly,  while  as  many  as  four  dozen  of  common  spectacle-glasses  are 
grouid  and  polished  together.  When  many  are  thus  fixed  on  one 
runn  t,  the  number  must  be  such  as  will  admit  of  their  being  ar- 
ranged symmetrically  around  a  central  lens,  as  7,  13,  or  21 ;  or 
sometimes  4  form  the  nucleus,  and  then  the  numbers  run  14,  30. 
Lenses  of  ordinary  quality  are  usually  ground  true  and  polished  7 
at  a  time.     This  runner,  with  its  lenses  attached,  is  shown  m  fg.  410. 

The  cement  at  the  back  of  the  lenses  is  first  flattened  with  a  heated  iron.  The  cast-iron 
runner  is  heated  just  sufficiently  to  melt  the  cement,  and  carefully  placed  upon  the  cemented 
backs  of  the  lenses.  As  soon  as  the  cement  is  sufficiently  softened  to  adhere  firmly  to  the 
runner,  it  is  cooled  with  a  wet  sponge,  as  the  cement  must  only  be  so  far  fused  as  to  fill  up 
the  spaces  nearly,  but  not  quite,  level  with  the  surface  of  the  lenses.  The  block  of  lenses 
is  now  mounted  upon  a  post,  and  ground  with  the  concave  brass  tool,  {fig.  409,)  motion  being 
given  to  it  either  by  the  hand  or  by  machinery  similar  to  the  sweeping  motion  already 
named.  As  the  griading  proceeds,  the  fineness  of  the  emery  powder  employed  is  increased, 
until  in  the  last  operation  it  is  sufficiently  fine  to  produce  a  semi-polished  surface.  This 
grinding  being  completed  successfully,  the  lenses  have  to  be  polished.  The  polisher  is 
made  by  warming  a  cast-iron  shell  and  coating  it  uniformly  about  one-quarter  of  an  inch 
thijk  with  melted  cement.  A  piece  of  thick  woollen  cloth  is  cut  to  the  size  of  the  polisher 
and  secured  to  it,  and  pressed  into  form  by  working  the  brass  tool  within  it.  When  this  is 
properly  adjusted  it  is  covered  with  very  finely  divided  putty  powder,  sprinkled  with  a  little 
water,  and  the  powder  worked  into  the  pores  of  the  cloth  with  the  brass  convex  tool.  Ite- 
peated  supplies  of  p'  tty  powder  are  put  on  the  polisher  until  it  is  made  quite  level,  and  it 
is  worked  smooth  with  the  tool.  Many  hours  are  expended  in  the  proper  preparation  of  a 
polisher.  When  completed  it  is  placed  upon  the  block  of  lenses  still  fixed  to  the  post,  and 
worked  with  wide  and  narrow  elliptical  strokes.  Where  a  very  large  number  of  glasses  are 
grounil  or  polished  at  the  same  time,  this  peculiar  motion  is  imitated  by  the  eccentric  move- 
ment of  a  lever  attached  to  the  revolving  shaft.  In  the  processes  of  grinding  and  polishing, 
other  materials  besides  emery  and  putty  powder  are  sometimes  employed,  such  as  raddle, 
a'l  earthy  oxide  of  iron,  the  finer  kinds  of  which  are  much  employed  in  the  large  lens  man- 
ufactory at  Sheffield. 

Much  more  might  be  said  on  the  subject  of  grinding  and  polishing  lenses,  but  it  is  one 
of  those  processes  of  manufacture  which  scarcely  come  within  the  limits  of  the  present 
work.  Still  it  was  thought  to  be  of  sufficient  importance  to  receive  some  general  notice. 
The  grinding  and  polisliing  of  the  finer  varii^ties  of  lenses  for  telescopes,  microscopes, 
and  the  like,  require  extremely  nice  manipulation.  The  best  account  of  the  processes 
and  of  the  instruments  used  is  one  by  the  late  Andrew  Ross,  in  the  fifly-third  volume  of 


YU  LIGHT. 

the  Tmnsactions  of  the  Society  of  Arts.  In  IloltzapffePs  Mechanical  3Ia7iip2daiion  there 
is  also  some  very  excellent  practie;;!  information. 

LIGHT.  {Lumiere,  Fr. ;  Licht,  (ierm.)  The  operation  of  light  as  an  agent  in  the  arts 
or  manufacturers  has  scarcely  yet  received  attention.  Sufficient  evidence  has,  however, 
been  collected  to  show  that  it  is  of  the  utmost  importance  in  producing  many  of  the  re- 
niarliable  changes  in  bodies  which  are  desired  in  some  cases  as  the  result,  but  which,  in 
others,  are  to  be,  if  possible,  avoided. 

There  is  a  very  general  misconception  as  to  the  power  or  principle  to  which  certain 
phenomena,  the  result  of  exposure  to  sunshine,  are  to  be  referred.  In  general  light  is 
regarded  as  the  principle  in  action,  whereas  frequently  it  has  nothing  whatever  to  do 
with  the  change.  A  few  words,  therefore,  in  explanation  are  necessary.  The  solar  rays 
commonly  spoken  of  as  light  contains  in  addition  to  its  Inminoits  power,  calorific  power, 
chemical  power,  and  in  all  probability  electrical  power.  These  phenomena  can  be  sepa- 
rated one  from  the  other,  and  individually  studied.  All  the  photographic  phenomena  are 
dependent  upon  the  chemical  (actinic)  power.  Many  of  the  peculiar  changes  which  are 
effected  in  organic  bodies  are  evidently  due  to  light,  and  the  phenomena  which  depend 
entirely  on  heat  are  well  known. 

Ilerschel  has  directed  attention  to  some  of  the  most  striking  phenomena  of  light, 
especially  its  action  upon  vegetable  colors.  As  these  have  direct  reference  to  the  per- 
manence of  dyes,  they  are  deserving  of  great  attention.  The  following  quotation  from 
Sir  John  Herschell's  paper  "  On  the  Cheviical  Action  of  the  Rays  of  the  Solar  Spectrum, 
dr.,"  will  explain  his  views  and  give  the  character  of  the  phenomena  which  he  has  stud- 
ied.    He  writes: — 

"  The  evidence  we  have  obtained  by  the  foregoing  experiments  of  the  existence  of 
chemical  actions  of  very  different  and  to  a  certain  extent  opposite  characters  at  the  oppo- 
site extremities  (or  rather,  as  we  ought  to  express  it,  in  the  opposite  regions)  of  the  spectrum, 
will  naturally  give  rise  to  many  interesting  speculations  and  conclusions,  of  which  those 
I  am  about  to  state  will  probably  not  be  regarded  as  among  the  least  so.  We  all  know 
that  colors  of  vegetable  origin  are  usually  considered  to  be  destroyed  and  whitened  by 
the  continual  action  of  light.  The  process,  however,  is  too  slow  to  be  made  the  subject 
of  any  satisfactory  series  of  experiments,  and,  in  consequence,  this  subject,  so  interest- 
in"-  to  the  painter,  the  dyer,  and  the  general  artist,  has  been  allowed  to  remain  uninves- 
tigated. As  soon,  however,  as  these  evidences  of  a  counterbalance  of  mutually  opposing 
actions,  in  the  elements  of  which  the  solar  light  consists,  offered  themselves  to  view,  it 
occurred  to  me,  as  a  reasonable  subject  of  inquiry,  whether  this  slow  destruction  of  veg- 
etable tints  might  not  be  due  to  the  feeble  amount  of  residual  action  outstanding  after 
imperfect  mutual  compensation,  in  the  ordinary  way  in  which  such  colors  are  presented 
to  light,  i.  e.  to  mixed  rays.  It  appeared,  therefore,  to  merit  inquiry,  whether  such  colors, 
subjected  to  the  uncompensated  action  of  the  elementary  rays  of  the  spectrum,  might 
not  undergo  changes  differing  both  in  kind  and  in  degree  which  mixed  light  produces  on 
them,  and  might  not,  moreover,  by  such  changes  indicate  chemical  properties  in  the  rays 
themselves  hitherto  unknown. 

"  One  of  the  most  intense  and  beautiful  of  the  vegetable  blues  is  that  yielded  by  the 
blue  petals  of  the  dark  velvety  varieties  of  the  connnon  heartsease  {Viola  tricolor).  It 
is  best  extracted  by  alcohol.  The  alcoholic  tincture  so  obtained,  after  a  few  days'  keeping 
in  a  stoppered  phial,  loses  its  fine  blue  color,  and  changes  to  a  paUid  brownish  red,  like 
that  of  port  wine  discolored  by  age. 

"  When  spread  on  paper  it  hardly  tinges  it  at  first,  and  might  be  supposed  to  have 
lost  all  coloring  virtue,  but  that  a  few  drops  of  very  dilute  sulphuric  acid  sprinkled  over 
it,  indicate  by  the  beautiful  and  intese  rose  color  developed  where  they  fall,  the  continued 
existence  of  the  colaring  principle.  As  the  paper  so  moistened  with  the  tincture  dries, 
however,  the  original  blue  color  begins  to  appear,  and  when  quite  dry  is  full  and  rich. 
The  tincture  by  long  keeping  loses  this  quality,  and  does  not  seem  capable  of  being 
restored.  But  the  paper  preserves  its  color  well,  and  is  even  rather  remarkable  among 
vegetable  colors  for  its  permanence  in  the  dark  or  in  common  daylight. 

"  A  paper  so  tinged  of  a  very  fine  and  full  blue  color,  was  exposed  to  the  solar  spec- 
trum concentrated,  as  usual,  (October  11,  1839,)  by  a  prism  and  lens ;  a  water-prism,  how- 
ever, was  used  in  the  experiment,  to  command  as  large  an  area  of  sunbeam  as  possible. 
The  sun  was  poor  and  desultory;  nevertheless  in  half  an  hour  there  was  an  evident 
commencement  of  whitening  from  the  fiducial  yellow  ray  to  the  mean  red.  In  two  hours 
and  a  half,  the  sunshine  continuing  very  much  interrupted  by  clouds,  the  effect  was  marked 
by  a  considerable  white  patch  extending  from  the  extreme  red  to  the  end  of  the  violet 
ray,  but  not  traceable  beyond  that  limit.  Its  commencement  and  termination  were,  how- 
ever, very  feeble,  graduating  off"  insensibly ;  but  at  the  maximum,  which  occurred  a  little 
below  the  fiducial  point,  (corresponding  nearly  with  the  orange  rays  of  the  luminous 
spectrum,)  the  blue  color  was  completely  discharged.  Beyond  the  violet  there  was  no 
indication  of  increase  of  color,  or  of  any  other  action.  I  do  not  find  that  this  paper  is 
discolored  by  mere  radiant  heat  unaccompanied  with  light." 


LIGHT-HOUSE.  715 

Dr.  George  Wilson  of  Edinburgh  made  some  exceedingly  interesting  experiments  on 
the  injiucnce  of  sunlight  Oder  the  action  of  the  dry  gases  on  organic  colors.  The  results 
arrived  at  were  communicated  to  the  British  Association,  and  an  abstract  of  the  com- 
munication is  published  in  their  transactions.  The  experiments  were  on  chlorine,  sul- 
phurous acid,  sulphuretted  hydrogen,  carbonic  acid,  and  a  mixture  of  sulphurous  and 
carbonic  acid,  oxygen,  hydrogen,  and  nitrogen,  on  organic  coloring  matters.  "I  had 
ascertained,"  says  Dr.  George  Wilson,  "  the  action  of  the  gases  mentioned  already  on 
vegetable  coloring  matters,  so  arranged  that  both  coloring  matter  and  gas  should  be  as 
dry  as  possible,  the  aim  of  the  inquiry  being  to  elucidate  the  theory  of  bleaching,  by 
accounting  for  the  action  of  dry  chlorine  upon  dry  colors.  In  the  course  of  this  inquiry, 
I  ascertained  that  in  darkness  dry  chlorine  may  be  ke[)t  for  three  years  in  contact  with 
colors  without  bleaching  them,  although  when  moist  it  destroys  their  tints  in  a  few  sec- 
onds, (see  Bleaching;)  and  I  thought  it  desirable  to  ascertain  whether  dry  chlorine  was 
equally  powerless  as  a  bleacher  when  assisted  by  sunlight.  The  general  result  of  the 
inquiry  was,  that  a  few  weeks  sufficed  for  the  bleaching  of  a  body  by  chlorine  in  sun- 
light, where  months,  I  may  even  say  years,  would  not  avail  in  darkuess. "  The  form  of 
the  experiment  was  as  follows: — Four  tubes  were  connected  together  so  as  to  form  a  con- 
tinuous canal,  through  which  a  current  of  gas  could  be  sent.  Each  tube  contained  a 
small  glass  rod  on  which  seven  pieces  of  differently  colored  papers  were  spiked.  It  is 
not  necessary  liere  to  state  the  colors  employed,  suffice  it  to  say,  that  all  the  tubes  thus 
contained  seven  different  colored  papers,  of  different  origins,  and  easily  distinguishable 
by  the  eye.  They  were  arranged  in  the  same  order  in  each  tube,  and  were  prepared  as 
nearly  as  possible  of  the  same  shade.  These  papers  were  carefully  deprived  of  every 
trace  of  moisture  by  a  current  of  very  dry  air.  The  tubes  were  then  filled  with  the  gas, 
also  dried,  on  which  the  experiment  was  to  be  made.  One  tube  of  each  series  was  kept 
in  darkness,  two  others  were  exposed  in  a  western  aspect  behind  glass,  and  the  other 
was  turned  to  the  south  in  the  open  air. 

The  results  were  as  follows : — In  the  dark  chlorine  tube  the  colors  were  very  little  alter- 
ed, and  would  probably  have  been  altered  less  had  not  the  tube  been  frequently  exposed 
to  light  for  the  sake  of  examination.  In  the  western  tube,  the  original  gray  and  green 
wallflower  papers  became  of  a  bright  crimson,  the  blue  htmus  bright  red,  and  the  brown 
rhubarb  yellow.  The  whole  of  the  chlorine  had  apparently  entered  into  combination 
with  the  coloring  matters,  for  the  yellow  tint  of  the  gas  had  totally  disappeared.  In  the 
southern  tube  the  color  of  the  chlorine  could  still  be  seen,  the  reddening  action  was  less 
decided,  and  the  bleaching  action  was  more  powerfully  evinced.  The  general  result  was 
that  the  action  of  sunlight  is  less  uniform  than  might  have  been  expected  in  increasing 
the  bleaching  power  of  chlorine,  or  while  some  tints  rapidly  disappeared  under  its  action 
assisted  by  light,  other  colors  remained,  in  apparently  the  very  same  circumstances, 
unaffected. 

Sulphurous  acidy  if  thoroughly  dried,  may  be  kept  for  months  in  contact  with  dry 
colors  without  altering  them ;  under  the  influence  of  sunlight  it  however  recovers  to 
some  extent  its  bleaching  power. 

Sulphuretted  hydrogen  acts  as  a  weak  acid,  and  readily  as  a  bleacher  when  moist,  and 
becomes  inactive  in  both  respects  if  made  dry  and  kept  in  darkuess.  With  the  assist- 
ance of  sunlight  it  recovers  in  no  inconsiderable  degree  its  bleaching  power. 

Oxygen  is  a  well-known  bleaching  agent,  but  when  dry  its  action  upon  coloring  mat- 
ter in  the  dark  is  extremely  slow.     In  sunlight,  however,  it  recovers  its  bleaching  power. 

Carbonic  acid,  when  dry  in  darkness,  loses  all  power  on  coloring  matter,  but  a  faint 
bleaching  action  is  exerted  by  it  under  exposure  to  sunlight. 

Hydrogen  is  without  any  action  when  dry  upon  colors,  but  it  acquires  a  slight  decol- 
orizing power  when  exposed  to  sunshine. 

"  The  general  result,  "  concludes  Dr.  George  Wilson,  "  of  this  inquiry,  so  far  as  it  has 
yet  proceeded,  is,  that  the  bleaching  gases,  viz.,  chlorine,  sulphurous  acid,  sulphuretted 
hydrogen,  and  oxygen,  lose  nearly  all  their  bleaching  power  if  dry  and  in  darkness,  but 
all  recover  it,  and  chlorine  in  a  most  marked  degree,  by  exposure  to  sunlight." 

All  these  experiments  appear  to  show  that  the  action  of  the  solar  rays  on  vegetable 
colors  is  dependent  upon  the  power  possessed  by  one  set  of  rays  to  aid  in  the  oxida- 
tion or  chemical  changes  of  the  organic  compound  constituting  the  coloring  matter. 
The  whole  matter  requires  careful  investigatiou. 

It  is  a  proved  fact,  that  coloring  matters,  either  from  the  mineral  or  the  vegetable  king- 
doms, are  much  brighter  when  they  arc  precipitated  from  their  solutions  in  bright  sun- 
shine, than  if  precipitated  on  a  cloudy  day  or  in  the  dark.  It  must  not  be  supposed  that 
all  the  changes  observed  are  due  to  chemical  action  ;  there  can  be  no  doubt  but  many 
arc  purely  physical  phenomena,  that  is,  the  result  of  molecular  change,  without  any 
chemical  disturbance. 

LIGHT- IIOUSI].  The  importance  of  lights  of  great  power  and  of  a  distinguishable 
character  around  our  coasts  is  admitted  by  all.     One  of  the  noblest  efforts  of  humanity 


716  LIGHT-HOUSE. 

is  certainly  the  construction  of  those  guides  to  the  mariners  upon  rocks  which  exist  in 
the  tracks  of  ships,  or  upon  dangerous  shores  and  the  mouths  of  harbors.  This  is  not 
the  place  to  enter  largely  upon  any  special  description  of  the  lights  which  are  adopted 
around  our  shores;  a  brief  account  only  will  be  given  of  some  of  the  more  remarkable 
principles  which  have  been  introduced  of  late  years  by  the  Trinity  Board. 

The  eaily  ligiit-houses  appear  to  have  been  illumin^ited  by  coal  or  wood  fires  contained 
in  "chauffers."  The  Isle  of  Man  light  was  of  this  kind  until  1816.  The  first  decided 
improvement  was  made  by  Argand,  in  1784,  who  invented  a  lamp  with  a  circular  wick, 
the  flame  being  supplied  l)y  an  external  and  internal  current  of  air.  To  make  these 
lamps  more  effective  for  light-house  illumination,  and  to  prevent  the  ray  of  light  escaping 
on  all  sides,  a  reflector  was  added  in  1780  by  M.  Lenoir;  this  threw  the  light  forward  in 
]iarallel  rays  towards  such  points  of  the  horizon  as  would  be  useful  to  the  mariner.  Good 
reflectors  increase  the  luminous  effect  of  a  lamp  about  400  times;  this  is  the  "  catoptric" 
system  of  lighting.  When  reflectors  are  used,  there  is  a  certain  cjuantity  of  light  lost, 
and  the  "  dioptric  "  or  refractitu/  system,  invented  by  the  late  M.  Augustin  Fresnel  in 
1822,  is  designed  to  obviate  this  effect  to  some  extent.  The  "  catadioptric  "  system  is  a 
still  further  improvement,  and  acts  both  by  refraction  and  reflection.  Lights  of  the  first 
order  have  an  interior  radius  or  focal  distance  of  3G'22  inches,  and  are  lighted  by  a 
lamp  of  four  concentric  wicks,  consuming  570  gallons  of  oil  per  annum. 

The  appearance  of  light  called  short  eclipses  has  hitherto  been  obtained  by  the  fol- 
lowing arrangen.ent : — 

An  apparatus  for  a  fixed  light  being  provided,  composed  of  a  central  cylinder  and 
two  zones  of  catadioptric  rings  forming  a  cupola  and  lower  part,  a  certain  number  of 
lenses  are  arranged  at  equal  distances  from  each  other,  placed  upon  an  exterior  movable 
fr.ime  making  its  revolution  arouml  the  apparatus  in  a  given  period.  These  lenses,  com- 
posed of  vertical  prisms,  are  of  the  same  altitude  as  the  cylinder,  and  the  radius  of  their 
curves  is  in  opposite  directions  to  those  of  the  cylinder,  in  such  a  manner  that  at  their 
passage  they  converge  into  a  parallel  pencil  of  light,  all  the  diverging  raj^s  emitted  hori- 
zontally from  the  cyhnder,  producing  a  brilliant  effect,  hke  that  obtained  by  the  use  of 
annular  lenses  at  the  revolving  light-houses. 

Before  proceeding  wit;h  the  description  of  the  lenses,  the  following  notices  may  be  of 
interest: — 

The  Eddystone  Light-house,  9|  miles  from  the  Rame  Head,  on  the  coast  of  Cornwall, 
was  erected  of  timber  by  Winstaidey  in  IG'.tlJ-OS,  and  was  washed  away  in  17u3.  It  was 
rebuilt  by  Rudyard  in  1706,  and  destroyed  by  fire  in  1755.  The  present  edifice  was 
erected  by  Smeaton  1757-59.  Tallow  candles  were  used  in  the  first  instance  for  the 
lights;  but  iu  1807  Argand  lamps,  with  paraboloidal  reflectors  of  silvered  copper,  were 
substituted. 

The  Skerry vore  Rocks,  about  12  miles  south-west  of  Tyree  on  the  coast  of  Argyle- 
shire,  lying  in  the  track  of  the  shipping  of  Liverpool  and  of  the  Clyde  had  long  been 
regarded  with  dread  by  the  mariners  frequenting  these  seas.  The  extreme  difficulty  of 
the  position,  exposed  to  the  unbroken  force  of  the  Atlantic  Ocean,  had  alone  deterred 
the  commissioners  of  northern  lights  from  the  attempt  to  place  a  light  upon  this  danger- 
ous spot ;  but  in  1834  they  caused  the  reef  to  be  surveyed,  and  in  1838  Mr.  Alan  Ste- 
phenson, their  engineer,  inheriting  his  f  ither's  energy  and  scientific  skill,  commenced 
his  operations  upon  a  site  from  which  "nothing  could  be  seen  for  miles  around  but  white 
foaming  breakers,  and  nothing  «ould  be  heard  but  the  howling  of  the  winds  and  the 
lashing  of  the  waves."  His  design  was  an  adaptation  of  Smeaton's  lower  of  the  Eddy- 
stone  to  the  peculiar  situation,  a  circumstance  with  which  he  had  to  contend.  He  estab- 
lishi'd  a  circular  base  42  feet  in  diameter,  rising  in  a  solid  mass  of  gneiss  or  granite,  but 
diminishing  in  diameter  to  the  height  of  2(3  feet,  and  presenting  an  even  concave  sur- 
fiicc  all  around  to  the  action  of  the  waves.  Immediately  above  this  level  the  walls  are 
9"58  feet  tiiick,  diminishing  in  thickness  as  the  tower  rises  to  its  highest  elevation,  where 
the  walls  are  reduced  to  two  feet  in  thickness,  and  the  diameter  to  16  feet.  The  tower  is 
built  of  granite  from  the  islands  of  Tyree  and  Mull,  and  its  height  from  the  base  is  138 
feet  8  inches.  In  the  intervals  left  by  the  thickness  of  the  walls  are  the  stairs,  a  space 
for  the  necessary  supply  of  stores,  and  a  not  uncomfortable  habitation  for  three  attend- 
ants. The  rest  of  the  establishment,  stores,  &c.,  are  kept  at  the  depot  in  the  island  of 
Tyree.  The  light  of  the  Skerryvore  is  revolving,  and  is  produced  by  the  revolution  of 
eight  annular  lenses  around  a  central  lamp,  and  belongs  to  the  first  order  of  dioptric 
lights  in  the  svstem  of  Fresnel,  and  may  be  seen  from  a  vessel's  deck  at  a  distance  of  18 
miles. — Lord  De  Maule}i,  Juror''s  Report,  Great  Exhibition,  1851. 

Some  of  the  lenticular  arrangements  must  now  claim  attention.  Large  lenses,  or  any 
large  masses  of  glass,  are  liable  to  striaj,  which  by  dispersing,  occasion  a  loss  of  much 
light. 

"  In  order  to  improve  a  solid  lens  formed  of  one  piece  of  glass  whose  section  is  a, 
"*)  />.  I*.  F,  K,  D,  c.  A,  Buffon  proposed  to  cut  out  all  the  glass  left  white  in  the  figure, 


LIGHT-HOUSE.  717 

(411,)  namely,  the  portions  between  m  p  and  n  o,  and  between  n  o  and  the  left-hand  sur- 
f'lco  of  D  E.  A  lens  thus  constructed  would  be  incomparably  superior  to  a  solid  one, 
but  .-ujh  a  process  we  conceive  to  be  impracticable  on  a  large  scale,  from  the  extreme 
(UfhcuUy  of  polishing  the  surfaces  a  vi,  b  p,c  v,  f  o, 
and  the  left-hand  surface  of  d  k  ;  and  even  if  it  were  *'l  1 
practical  the  greatest  imperfections  of  the  glass  might 
liappen  to  occur  in  the  parts  which  are  left.  In  oidcr 
to  remove  those  imperfections  and  to  construct  lenses 
of  any  siaic,"  says  Sir  David  Brew  ster,  ''  I  proposed 
in  1811  to  build  them  up  of  separate  zones  or  rings, 
cich  of  which  rings  was  again  to  be  composed  of 
s.'parate  segments,  as  shown  in  the  front  view  of  the 
lens  in  fg.  412.  This  lens  is  composed  of  one  cen- 
tral lens  A  B  c  D,  corresponding  with  its  section  n  e, 
in  fg.  412;  of  a  middle  ring  g  e  l  i,  corresponding 
to  c  D  E  F,  and  consisting  of  4  segments ;  and  another 

ring  N  p  R  T,  corresponding  to  a  c  f  b,  and  consisting  of  8  segments.  The  preceding 
construction  obviously  puts  it  in  our  power  to  execute  those  lenses  to  which  I  have  given 
the  name  of  pol>/zona'  lenses,  of  pure  flint  glass  free  from  veins;  but  it  possesses  another 
great  advantage,  namely,  that  of  enabling  us  to  correct  very  nearly  the  spherical  aberra- 
tion by  maUiiig  the  foci  of  each  zone  to  coincide." — Brewster. 

This  description  will  enable  the  reader  to  understand  the  system  which  has  been 
adopted  by  Fresnel  and  carried  out  by  the  French  government,  and  by  our  own  commis- 
sioners of  lights. 

In  the  fixed  dioptric  light  of  Fresnel,  the  flame  is  placed  in  the  centre  of  the  appa- 
ratus, and  within  a  cylindric  reflector  of  glass,  of  a  vertical  refracting  power,  the  breadth 
and  height  of  a  strip  of  light  emitted  by  it  beinoj  dependent  upon  the  size  of  the  flame 
and  the  heiglu  of  the  reflector  itself;  above  and  below  is  placed  a  series  of  reflecting 
prismatic  rings  or  zones  for  collecting  the  upper  and  lower  diverging  rays,  which,  falling 
upon  the  inner  side  of  the  zone,  are  refracted,  pass  through  the  second  side,  where  they 
suffer  total  reflection,  and,  passing  out  on  the  outer  side  of  the  zone,  are  again  refracted. 
The  effect  of  these  zones  is  to  lengthen  the  vertical  strip  of  light,  the  size  of  which  is 
dependent  upon  the  breadth  of  the  flame  and  the  height  of  the  apparatus. 

In  Fresnel's  revolving  light-house,  a  large  flame  is  placed  in  the  centre  of  a  revolving 
frame  which  carries  a  number  of  lenses  on  a  large  scale  and  of  various  curvatures,  for  the 
avoidance  of  spherical  aberration.  With  the  view  of  collecting  the  diverging  rays  above 
the  flame,  an  arrangement  of  lenses  and  silvered  mirrors  is  placed  immediately  over  it. 
By  this  compound  arrangement,  the  simply  revolving  character  of  the  apparatus  is  de- 
stroyed, as,  in  addition  to  the  revolving  flash,  a  vertical  and  fixed  light  is  at  all  times 
seen,  added  to  which  agri>at  loss  of  light  must  be  sustained  by  the  loss  of  metallic  reflect- 
ors. In  1851,  Messrs.  Wilkiiis  and  Letourneau  exhibited  a  catadioptric  apparatus  of 
great  utility.     It  was  thus  described  by  the  exhibitors: — 

The  first  improvement  has  special  reference  to  the  light,  and  produces  a  considerable 
increase  in  its  power,  whilst  the  simplicity  of  the  optical  arrangements  is  also  regarded. 
It  consists,  firstly,  in  completely  dispensing  with  the  movable  central  cylindrical  lenses; 
secondly,  it  replaces  these  by  a  single  revolving  cylinder  composed  of  four  annular  lenses 
and  four  lenses  of  a  fixed  light  introduced  between  them  ;  but  the  iniml)er  of  each  vary- 
ing according  to  the  succession  of  flashes  to  be  produced  in  the  period  of  revolution. 

The  second  improvement,  of  which  already  some  applications  tliat  have  been  made 
serve  to  show  tlie  importance,  consists  in  a  new  method  of  arranging  the  revolving  parts, 
experi(.'nce  having  shown  that  the  arrangennmts  at  present  in  use  are  very  faidty.  A 
short  time  is  sufficient  for  tlio  action  of  the  friction  rollers,  revolving  on  two  paralhd 
planes,  to  produce  by  a  succession  of  cuttings  a  sufficiently  deep  groove  to  destroy  the 
regularity  of  the  rotary  movement.  To  obviate  this  great  inconvenience,  the  friction 
rollers  are  so  placed  and  fitted,  on  an  iron  axis  with  regulating  si'rews  and  traversing 
between  two  levelled  surfaces,  that  when  an  indentation  is  made  in  one  place  they  can 
be  adjusted  to  another  part  of  the  plates  which  is  not  so  worn. 

The  third  improvcmuit  produces  the  result  of  an  increase  of  the  power  of  the  flashes 
in  revolving  lighthouse  apparatus  to  doul)le  what  has  been  obtained  hitherto.  By  means 
of  lenses  of  vertical  prisms  placed  in  the  ])rolongation  of  the  central  annular  lenses,  the 
diverging  rays  emerging  from  the  catadioptric  zone  are  brought  into  a  straight  line,  and 
a  coincidence  of  the  three  lenses  is  obtained. 

The  whole  of  the  prisms,  lenses,  and  zones  arc  mounted  with  strength  artd  simplicity, 
accurately  ground  and  polished  to  the  connect  curves  according  to  their  respective  posi- 
tions, so  as  to  properly  develop  this  beautiful  system  of  Fresnel.  The  glass  of  which 
they  are  composed  should  be  of  the  clearest  crystal  color,  and  fiec  from  that  green  hue 
which  so  materially  reduces  the  power  of  the  light,  and  is  considered  objectionable  for 


718  LIGIIT-nOUSE. 

apparatus  of  this  kind.  Tlie  lamp  by  which  the  apparatus  is  to  bo  lighted  consists  of  a 
concentric  burner  with  four  circular  wicl<s  attached  to  a  lamp  of  simple  construction 
the  oil  being  forced  up  to  the  burner  by  atmospheric  pressure  only,  so  that  there  are  no 
delicate  pumps  or  niacliinery  to  become  deranged. 

S/ephensoH\i  revolving  Utjht-housc. — This  apparatus  consists  of  two  parts.  The  prin- 
cipal part  is  a  right  octagonal  hollow  prism  composed  of  eight  large  leiise.'-,  which  throw 
out  a  powerful  beam  of  light  whenever  the  axis  of  a  single  lens  comes  in  the  line  between 
the  observer  and  the  focus.  This  occurs  once  in  a  minute,  as  the  frame  which  bears  the 
lens  revolves  iu  eight  minutes  on  the  rollers  placed  beneath.  The  subsidiary  parts  con- 
sist of  eight  pyramidal  lenses  inclined  at  an  angle  of  30°  to  the  horizon,  and  forming 
together  a  hollow  truncated  cone,  which  rests  upon  the  flame  like  a  cap.  Above  these 
smaller  lenses  (which  can  only  be  seen  by  looking  fro:n  below)  are  placed  eight  plane 
mii'rors,  whose  surfaces  being  inclined  to  the  horizon  at  50"  in  the  direction  opposite 
to  that  of  the  pryamidul  lenses,  finally  cause  all  the  light  made  parallel  by  the  refraction 
of  these  lenses  to  leave  the  mirror  in  a  horizontal  direction.  The  only  object  of  this 
part  is  to  turn  to  useful  account,  by  piolonging  the  duration  of  the  flash,  that  part  of 
the  light  which  would  otherwise  escape  into  the  atmosphere  above  the  main  lenses.  This 
is  effected  by  giving  to  the  upper  lenses  a  slight  horizontal  divergence  from  the  vertical 
plane  of  the  principal  lenses.  Below  are  five  tiers  of  totally  reflecting  prisms,  which 
intercept  the  light  that  passes  below  the  great  leriscs,  and  by  means  of  two  reflections 
and  an  intermediate  refraction  project  them  in  the  shape  of  a  fl;it  ring  to  the  horizon. 

St ephe 71  soil's  Jixcd  dioptric  ajjjjuratus  of  the  fii'st  order  (same  as  that  at  the  Isle  of 
May,  with  various  improvements.)  The  principal  part  consists  of  a  cyliudric  belt  of  glass 
whicii  surrounds  the  flame  in  the  centre,  and  by  its  action  refracts  the  light  in  a  vertical 
direction  upwards  and  downwards,  so  as  to  be  parallel  with  the  focal  plane  of  the  system. 
In  this  way  it  throws  out  a  flat  ring  of  light  equally  intense  in  every  direction.  To  near 
observers,  this  action  presents  a  narrow  vertical  band  of  light,  depending  for  its  breadth 
on  the  extent  of  the  horizontal  angle  embraced  by  the  eye.  This  arrangement  there- 
fore fulfils  all  the  conditions  of  a  fixed  light,  and  surpasses  in  effect  any  arrangement 
of  parabolic  reflectors.  In  order  to  save  the  light  which  would  be  lost  in  passing  above 
and  below  the  cylindrical  belt,  curved  mirrors  with  their  common  focus  in  the  lamp  were 
formerly  used ;  but  by  the  present  engineer,  the  adaptation  of  catadioptric  zones  to 
this  part  of  the  apparatus  was,  after  much  laboi-,  successfully  carried  out.  These  zones 
are  triangular,  and  act  by  total  reflection,  the  inner  face  refracting,  the  second  totallt/ 
rejfcctinrj,  and  the  third,  or  outer  face,  a  second  time  refracting,  so  as  to  cause  the  light  to 
cmQY^Q  horizontallii.  The  apparatus  has  received  many  smaller  changes  by  the  introduc- 
tion of  a  new  mode  of  groui)ing  the  various  parts  of  the  framework,  by  which  the  pas- 
S:igc  of  the  light  is  less  obscured  in  every  azimuth. 

Mechanical  lamps  of  four  wicks  are  used  in  these  light-houses;  in  these  the  oil  is  kept 
continually  overflowing  by  means  of  pumps  which  raise  it  from  the  cistern  below  ;  thus 
the  rapid  carl)onization  of  the  wicks,  which  would  be  caused  by  the  great  heat,  is  avoided. 
The  flames  of  the  lamp  reach  their  best  effect  in  three  hours  after  lighting,  i.  e.,  after  the 
whole  of  the  oil  in  the  cistern,  by  pa.ssing  and  repassitig  over  the  wicks  repeatedly,  has 
reached  its  maximum  temperature.  After  this  the  lamp  often  burns  14  hours  without 
sensible  diminution  of  the  light,  and  then  rapidly  falls.  The  height  varies  from  16  to 
20  times  tliat  of  the  Ai-gand  flame  of  an  inch  in  diameter;  and  the  quantity  of  oil  con- 
sumed by  it  is  greater  nearly  in  the  same  proportion. 

In  Stevensoii'x  ordinary  parabolic  reflector,  rendered  holophotal  (where  the  entire  light 
is  parallelized)  bj'  a  portion  of  a  catadioptric  antmlar  lens,  the  back  part  of  the  parabolic 
conoid  is  cut  off,  and  a  portion  of  a  spherical  mirror  substituted,  so  as  to  send  the  rays 
again  through  the  flame ;  while  \\\a  holophotal  catadioptric  annular  lens  appjaratus  is  a 
combination  of  a  hemispherical  mirror  and  a  lens  having  totally-reflecting  zones  ;  the 
peculiarity  of  this  arrangement  is,fhat  the  catadioptric  zones,  instead  of  transmitting  the 
light  in  parallel  horizontal  plates,  as  in  Fresnel's  ;i[)paratus,  produces,  as  it  were,  an  ex- 
tension of  the  lenticuliir  or  quaquaversal  action  of  the  central  lens  by  assembling  the  light 
around  its  axis  in  the  form  of  concentric  hollow  cylinders. 

Mr.  Chance,  of  Birmingham,  constructed  a  light-house  which  may  be  regarded  as  Fres- 
nel's revolving  light  rendered  holophotal.  This  arrangement  was  divided  into  three 
compartments,  the  upper  and  lower  of  which  were  compo'^ed  respectively  of  thirteen  and 
six  catadioptric  zones  which  juoduce  the  vertical  strip  of  light  cxtci'ding  the  whole  length 
of  the  apparatus,  and  is  similar  to  Fresners  dioptric  light.  The  central  or  catoptric  com- 
p:irtment  consisted  of  ciglit  lenses  of  three  feet  focal  length,  each  of  which  was  the 
centre  of  a  series  of  eleven  concentiic  prismatic  rings,  designed  to  produce  the  same 
refractive  effect  as  a  solid  lens  of  equal  size.  These  compound  lenses  were  mounted  ui)on 
a  revolving  frame  and  transmitted  horizontal  flashes  of  light  as  they  successively  rotated. 
The  motion  was  communicated  to  the  frame  by  a  clock  movement,  and  performs  one 
revolution  in  four  minutes;  consequently,  as  there  are  eight  lenses,  a  flash  of  light  is 
transmitted  every  thirty  seconds  to  the  horizon. 


LINEN.  V19 

LIGNITE.  In  Prussia,  Austria,  and  many  other  parts  of  the  continent,  lignite  forms 
a  very  important  proJiict,  being  largely  employed  for  domestic  and  for  manufactmiiig 
purposes.  In  tins  country,  with  the  single  exception  of  the  Bovcy  lleathfield  formation, 
whicli  is  used  in  the  adjoining  pottery,  lignite  is  not  employed. 

LIME.  Quicklime,  an  Oxide  of  Calcium.  Tliis  useful  substance  is_  prepared  by 
exposing  the  native  carbonate  of  lime  to  lieat,  by  which  the  carbonic  acid  is  expelled. 

This  operation  is  performed  in  a  manner  more  or  less  perfect,  by  burning  calcareous 
stones  in  kilns  or  furnaces. 

Anhydrous  lime,  or,  as  it  is  commonly  called,  "  qnichlimc,'"  is  an  amorphous  solid, 
varying'much  in  coherence,  according  to  the  kind  of  rock  from"  which  it  is  ol)tained  ;  its 
specific  gravity  varies  from  2-3  to  3.  Lime  is  one  of  the  most  infusible  bodies  which  we 
possess:  it  resists  the  highest  heats  of  our  furnaces. 

Wlien  exposed  to  air,  quicklime  rapidly  absorbs  water  and  evumbles  into  a  powder, 
commonly  known  as  slaked  lime,  which  is  a  hydrate  of  lime. 

Hydrate  of  lime,  when  exposed  to  the  air,  absorbs  carbonic  acid,  and  after  long  ex- 
posure it  is  converted  into  a  mixture  of  carbonate  of  lime  and  hydrate  of  lime  in  single 
equivalents.  Hydrate  of  lime  is  but  slightly  soluble  in  water,  729  to  733  parts  of  that 
fluid  dissolving  only  1  part  of  the  lime  at  ordinary  temperatures. 

Hydrate  of  lime  is  applied  to  numerous  purposes  in  the  arts  and  manufactures.  It 
is  chiefly  employed  in  the  preparation  of  mortar  for  building  purposes.     See  Moutar. 

The  pure  limes,  prepared  from  the  carbonates  of  lime,  form  an  imperfect  mortar 
suitable  only  for  dry  situations.  In  damp  buildings  or  in  wet  situations  they  never  set, 
(as  the  process  of  hardening  is  technically  termed,)  but  always  remain  in  a  pulpy  state. 
General  Pasley  says: — "The  unfitness  of  pure  lime  for  the  purposes  of  hydraulic  archi- 
tecture has  been  'proved  by  several  striking  circumstances  that  have  come  under  my 
personal  observation,  of  which  I  shall  only  mention  a  few.  First,  a  great  portion  of  the 
boundary  wall  of  Rochester  Castle  having  been  completely  undermined,  nearly  through- 
out its  whole  thickness,  which  was  considerable,  whilst  the  upper  part  of  the  same  wall 
was  left  standing,  I  had  always  ascribed  this  remarkable  breach  to  violence,  considering 
it  as  having  been  the  act  of  persons  intending  to  destroy  the  wall  for  the  sake  of  the 
stone ;  but  on  examining  it  more  accurately  after  I  had  begun  to  study  the  subject  of 
limes  and  cements,  I  observed  that  the  whole  of  the  breached  part  was  washed  by  the 
Medway  at  high  water,  and  that  all  the  mortar  of  a  small  portion  of  the  back  part  of  tilie 
foot  of  the  wall  still  left  standing  was  quite  soft,  l)Ut  that  towards  the  ordinary  high 
water  level  it  became  a  little  harder,  and  above  that  level  it  was  perfectly  sound.  I 
observed  the  same  process  at  the  outer  wall  of  Cockham  Wood  Fort,  on  the  left  bank 
of  the  Medway  below  Chatham,  of  which  the  upper  part  was  standing,  whilst  the  lower 
part  of  it  had  been  gradually  rubied  by  the  action  of  the  river  at  high  water  destroy- 
ing the  mortar." 

Observations  on  limes,  calcareous  cements,  etc. — The  peculiar  conditions  necessary  to 
insure  a  good  and  useful  mortar  for  building  purposes,  and  the  peculiarities  of  the  hy- 
draulic mortars  or  cements,  will  be  treated  of  under  Mortar,  which  sec. 

LINEN.  The  manufacture  of  linens  is  carried  on  extensively  in  the  north  of  Ireland, 
and  on  the  continent  in  Bohemia,  Moravia,  Silesia,  and  Galicia.  Of  the  entire  production, 
independent  of  the  Irish  linen,  about  five-twelfths  are  brought  into  the  market,  and  of 
this  quantity  the  bulk  must  be  of  domestic  manufacture,  since  few  great  linen  maim- 
fictories  exist  in  Austria.  Within  Austrian  domiiuons,  among  the  linen  fabrics,  table- 
cloths and  napkins,  vails,  cambrics,  dimities,  twills,  and  drills  are  important  articles.  In 
the  next  rank  we  must  place  the  manufacture  of  thread,  especially  in  Bohemia,  Moravia, 
and  Lombardy.  The  tape  manufacture  is  of  less  consequence;  and  as  to  the  business  of 
dyeing  and  printing,  that  has  been  almost  entirely  absorbed  by  the  cotton  nianufactin-e, 
and  is  now  in  requisition  for  thread  and  handkerchicl's  only. 

As  the  loss  resulting  from  the  processes  of  weaving,  bleaching,  &c.,  is  estimated  at 
about  10  per  cent.,  the  net  aggregate  of  these  manufiictures  of  linen,  thread,  &c.,  may  be 
assumed  at,  say,  1,037,000  cwt. ;  of  which  quantity  about  450,000  cwt.  come  into  the 
market,  the  rest  being  absorbed  by  domestic  consumption.  Since,  upon  an  average  of 
the  five  years  from  1843  to  1847,  there  appear  to  have  been  imported  from  abroad  only 
242  cwt.,  whereas  the  average  of  exports  for  the  same  period  shows  42,609  cwt.,  it  follows 
that  there  remained  for  home  consumption  about  1,000,000  cwt.  Thus,  on  a  popu- 
lation of  38,000,000  of  persons,  .about  2j  lbs.  would  fall  to  the  share  of  each  ;  but  this 
estimate  falls  much  below  the  truth,  when  we  consider  that  the  national  costume  in 
Hungary  and  Galicia  recpiircs  more  than  double  the  quantity  we  have  allowed  for.  In 
fact  the  crop  of  flax  is  esiimaied  to  be  10  per  cent,  higher  than  is  given  in  the  ofilcial 
reports  ;  but  the  consumption  of  even  3  lbs.  per  head,  which  would  thus  result,  is  yet 
smaller  than  in  reality  it  must  be.  In  the  imperial  army  of  Austria  the  quantity  used  up 
aiunially  by  each  man  averages  more  than  7  lbs. 

In  the  above  .statistics  of  the  manufacture  of  linen  goods  no  allowance  has  been  made 
for  the  extensive  production  of  rope  work  and  tlie  like. 


720  LINSEED  OIL. 

LIXSEED  OIL.  Linseed  oil  was  at  one  time  much  used  in  the  preparation  of  a  lini- 
ment, which,  as  it  is  one  of  tlie  ver_v  best  possible  applications  to  a  burnt  surface,  cannot  be 
too  generally  known.  If  equal  parts  of  linu-water  ajid  linnted  oil  are  agitated  together, 
they  form  a  thick  liniment,  wliich  may  be  ap|)lied  to  the  burn  Avith  a  brush  or  feather.  It 
relieves  at  once  from  pain,  and  forming  a  pellicle,  protects  the  abraded  parts  from  the  air. 
The  linimentum  calcis  of  the  Pharmacopoeia  is  equal  parts  of  lime-water  and  olive  oil ;  this 
is  a  more  elegant  but  a  less  effective  preparation.     See  Oils. 

LlyUOlilCE.  {Glci/i/rrh/za  Ojficinalis ;  I'vom  gli/ki/s,  sweet,  a.nd  rhiza,  a  root.)  The 
root  only  is  employed  ;  these  roots  are  thick,  long,  and  running  deep  in  the  ground. 

Besides  the  use  of  li(iuorice  roots  in  medicine,  they  are  also  employed  in  brewing,  and 
are  pretty  extensively  grown  for  these  purposes  in  some  parts  of  England.  Liquorice 
requires  a  rich,  deej),  div,  sandy  soil,  which,  previous  to  forming  a  new  jjlantation,  should 
be  trenched  to  the  depth  of  about  three  feet,  and  a  liberal  allowance  of  manure  regulaily 
nii.xed  with  the  earth  in  trenching.  The  i)lants,  which  are  procured  by  slipping  them 
from  those  in  old  plantations  are,  either  in  February  or  March,  dibbled  in  rows  three  feet 
apart,  and  from  eighteen  inches  to  two  feet  in  the  row.  They  require  three  sum- 
mers' growth  before  being  lit  for  use,  when  the  roots  are  obtained  l)y  retrenching  tlie 
whole,  and  they  are  then  stored  in  sand  for  their  preservation  until  required. — Peter 
Lairson. 

LITHOGRAPHY.  Engraving  on  stone,  for  maps,  geometrical  drawings  of  every  kind, 
patent  inventions,  machinery,  &c.,  is  performed  with  a  diamond  point  as  clearly  and  dis- 
tinctly as  if  executed  on  copper  or  steel  plates ;  to  print  these  engraved  stones,  the  ink 
should  be  laid  on  with  a  dabber,  not  a  roller.  Another  method  is  by  prejiaring  the  surface 
of  the  stone  with  a  thin  covering,  or  etching  ground,  of  gum  and  black,  upon  which  the 
design  is  traced  or  engraved  witli  an  etching  point;  it  then  appears  in  white  lines  upon  a 
black  surface.  In  this  state  the  stone  is  taken  to  the  printer,  wlio  applies  ink  to  the  en- 
graved part,  and  washing  off  the  gum,  the  drawing  appears  in  black  lines  upon  the  white 
surface  of  the  stone,  and  after  being  submitted  to  the  process  of  fixing,  described  below, 
is  ready  for  printing. 

Lithotint,  a  process  of  drawing  upon  stone  was  adopted,  first,  by  Mr.  J.  D.  Hard- 
ing, a  ie\r  years  back,  and  since  by  one  or  two  other  artists ;  several  works  were  at 
the  time  executed  by  this  method,  which  consists  in  paiutiiig  the  subject  with  a 
caftiel  hair  pencil,  dipped  in  a  preparation  of  liquid  lithographic  chalk,  using  the  latter  as 
if  it  were  an  ordinary  color,  or  Indian  ink,  sepia,  &c.  The  results  of  this  process  were, 
however,  so  uncertain  in  printing,  that  it  has  been  almost,  if  not  entirely,  abandoned. 

The  process  of  printing  a  subject  executed  in  lithography  is  as  follows : — The  drawing 
is  first  executed  by  the  artist  on  the  stone  in  as  perfect  and  finished  a  manner  as  if  done  on 
paper  or  card-board  :  the  stone  is  then  washed  over  with  nitric  acid,  diluted  with  gum, 
which  neutralizes  the  alkali,  or  soap,  contained  in  the  chalk,  fixes  the  drawing,  and 
cleanses  the  stone  at  the  same  time:  this  is  teclniically  called  etching.  The  acid  is 
then  washed  off  with  cold  water,  and  any  particles  of  the  crayon  or  other  substances 
which  may  have  adhered  to  the  surface,  are  removed  by  the  application  of  a  sponge 
dipped  in  spirits  of  turpentine :  the  stone  is  now  ready  for  printing :  it  is  slightly 
wetted,  charged  with  printing-ink  by  means  of  a  roller,  the  sheet  of  paper,  which  is 
to  receive  the  impression,  is  laid  on  it  in  a  damp  state,  and  the  whole  is  passed  through 
the  press. 

Chromolithograph!/,  or  printing  in  colors  from  stones,  {xpu/J-OL,  color,)  is  a  comparatively 
recent  introduction,  but  has  been  brought  to  such  perfection,  that  works  of  art  of  the 
highest  pictorial  excellence  are  sometimes  so  closely  imitated  as  to  deceive  very  competent 
judges.  A  portrait  of  Shakspcare,  for  example,  executed  in  chromolithography  by  Mr. 
Vincent  Brooks,  of  London,  from  an  old  oil  painting,  is  so  marvellous  a  copy  of  the  original 
as  almost  to  defy  detection.  Chromolithograjihy,  as  a  beautiful  medium  of  illustration,  is 
now  in  very  general  use.  The  process  may  be  thus  described  :  A  drawing  of  the  subject, 
in  outline,  on  tiansfer  tracing-paper,  is  made  in  the  ordinary  way  :  when  transferred  to  a 
stone,  this  drawing  is  called  the  kei/stone,  and  it  serves  as  a  guide  to  all  the  others,  for  it 
must  be  transferred  to  as  many  different  stones  as  there  are  colors  in  the  sutyect ;  as  many 
as  thirty  stones  have  been  used  in  the  production  of  one  colored  print.  The  first  stone  re- 
quired, generally  for  flat,  local  tints,  is  covered  with  lithographic  ink  where  the  parts  should 
be  of  solid  color ;  the  different  gradations  aie  produced  by  rubbing  the  stone  with  rubbing- 
stuff',  or  tint-ink,  made  of  soap,  shell  lac,  &c.,  kc.,  and  with  a  painted  lithographic  chalk 
where  necessary;  the  stone  is  then  washed  over  with  nitrous  acid,  and  goes  through  the 
entire  process  described  above.  A  roller  charged  with  lithographic  piinting-ink  is  then 
passed  over  it  to  ascertain  if  the  drawing  comes  as  desired  ;  and  the  ink  is  immediately 
afterwards  washed  off  with  turpentine  ;  if  satisfactory,  this  stone  is  ready  for  printing,  and 
is  worked  off  in  the  requisite  color ;  the  next  stone  undergoes  the  same  process  for  another 
color,  and  so  with  the  rest  till  the  work  is  complete :  it  will  of  course,  be  understood,  that 
before  any  simple  impression  is  finished,  it  will  have  to  pass  through  as  many  separate 


LOCKS. 


721 


printinfjs  as  there  are  drawings  on  stones.  The  colors  used  in  printing  arc  ground  up  with 
burnt  linseed  oil,  termed  vaDtish. — J.  D. 

LITMUS.  Dr.  Pereira,  writes : — "  Litmus  is  imported  from  Holland,  in  the  form  of 
small,  rectangular,  light,  and  friable  cakes  of  an  indigo  blue  color.  Examined  by  the  mi- 
croscope, we  find  sporuies  and  portions  of  the  epidermis  and  mcsothallus  of  some  species 
of  lichen,  mo.ss,  leaves,  sand,  &c.  The  odor  of  the  cakes  is  that  of  indigo  and  violets. 
Tiie  violet  odor  is  acquired  while  the  mixture  is  undergoing  fermentation,  and  is  common 
to  all  the  tinctorial  lichens.  It  has  led  some  writers  into  the  error  of  supposing  that  the 
litmus  makers  use  Florentine  orris  in  the  manufacture  of  litmus.  The  indigo  color  depends 
on  the  presence  of  indigo  in  the  litmus  cakes." 

LITMUS  PAPER.  Paper  colored  with  an  infusion  of  litmus,  used  as  a  test  for  the 
presence  of  acids. 

Faraday,  in  his  Chemical  Manipulation,  recommends  an  infusion  of  one  ounce  of 
litmus,  and  half  a  pint  of  hot  water.  Bibulous  paper  is  saturated  with  this.  Professor 
Graham  prefers  good  letter  paper  to  the  unsized  paper.  In  order  to  obtain  ver_v  del- 
icate test-paper,  the  alkali  in  the  litmus  must  be  almost  neutralized  by  a  minute  portion 
of  acid. 

LOCKS.  Although  locks  are  distinctly  a  manufacture,  yet  they  were  not  embraced  in 
former  editions  of  this  work,  the  chief  cause  of  this  being  the  desire  on  the  part  of  Dr.  Ure 
to  limit  the  articles  of  the  dictionary  to  such  manufiictures  as  were  not  comprehended  within 
his  meaning  of  the  term  handicraft. 

The  lock  manufacture  is  essentially  one  of  handicraft,  and  seeing  that  these  volumes 
could  not  possibly  enter  into  any  detailed  description  of  this  and  numerous  other  trades, 
as  watchmaking  and  the  like,  it  has  been  determined  that  a  brief  notice  of  the  several  kinds 
of  locks  alone  shall  find  a  place  in  its  pages. 

The  lock  manufacture  of  this  country  is  confined  almost  exclusively  to  Wolverhampton 
and  the  neighboring  village  of  Willeuhall.  There  are  very  few  large  manufactories,  almost 
all  kinds  of  locks  being  made  by  small  masters,  employing  from  half  a  dozen  to  a 
dozen  men. 

In  nearly  every  kind  of  lock,  a  bolt  shoots  out  from  the  box  or  lock,  usually  of  an 
oblong  shape,  and  catches  in  some  kind  of  staple  or  box  fixed  to  receive  it.  In  some  a 
staple  enters  the  lock,  and  the  bolt  passes  through  the  staple  within  the  lock.  The  lock 
of  a  room  door  is  of  the  first  character.  The  lock  of  a  writing  desk,  or  ordinary  box,  is 
of  the  second  kind.  The  key  is  merely  a  bent  piece  of  iron  which,  on  entering  the  lock, 
can  move  freely  and  push  forward  the  bolt.  To  the  bolts  of  superior  locks,  springs  are  at- 
tached, and  the  force  required  to  turn  the  key  in  a  lock  is  the  force  necessary  to  overcome 
the  resistance  of  the  springs.     The  following  t\yo  figures,  (413,  414,)  represent  the  character 


413 


414 


[ 


h 

J 

.'/q-K-v 

)) 

/il 

w 

a" 

of  a  lock  with  wards  or  wheels  which  are  introduced  to  give  safety.  Fiff.  413  is  an 
ordinary  back-spring  lock,  representing  the  bolt  half  shot ;  a  a"  are  notches  on  the  under 
side  of  the  bolt  connected  by  a  curved  portion ;  b  is  the  back-spring,  which  is  of  course 
compressed  as  the  curved  portion  of  the  bolt  passes  through  the  aperture  prepared  for  it  in 
the  rim  of  the  lock  ;  when  the  bolt  is  withdrawn,  the  notch  a'  rests  in  the  rim  ;  when  the 
bolt  is  shot,»the  notch  a"  rests  in  the  same  manner.  The  action  of  the  key  and  v,-ards  is 
shown  in  fiff.  414.  The  ctnved  pieces  of  metal  arc  the  wards;  and  there  arc  two  clefts  iu 
the  bit  of  the  key  to  enable  it  to  move  without  interruption. 

The  tumbler  lock  is  shown  in  its  most  sim])le  form  in  /f'//.  415.  Here  the  bolt  has  two 
slots  rt  a  in  the  upper  part ;  and  l)chind  the  bolt  is  a  kind  of  latch  6  which  carries  a  pro- 
jecting piece  of  metal  c ;  this  is  the  tumbler,  which  moves  freely  on  a  jtivot  at  the  other 
end.  When  the  l)olt  is  fully  shot,  the  projecting  piece  of  mclal  falls  into  one  notch  ;  and 
when  withdrawn,  it  falls  into  the  other.  It  will  be  evident  here,  that  the  action  of  the  key 
is  to  raise  the  tumbler,  so  that  the  bolt  has  free  motion  ;  this  action  will  be  intelligible  by 
Vol.  III.— 40 


722 


LOCKS. 


415 


tracing  the  action  of  the  key  on  the  dotted  lines.     These  tumbler  locks  are  greatly  varied 

in  character ;  but  in  principle  they  are  as  above  de- 
scribed. Numerous  well-known  locks  have  been 
patented,  the  most  remarkable  being  Chubb's  lock, 
which  has  been  fully  described  by  the  inventors  in  a 
paper  read  before  the  Institution  of  Civil  Engineers ; 
and  also  in  an  excellent  treatise  on  locks,  to  be  found 
in  Mr.  Weale's  series  of  useful  manuals.  This  lock 
is  essentially  a  tumbler  lock,  it  being  fitted  up  with  no 
less  than  six  tumblers ;  and  the  key  has  to  raise  by  a 
series  of  steps  these,  before  the  bolt  is  free  to  move. 
It  will  be  obvious,  that  unless  the  key  is  exactly  fitted 
to  move  these,  there  is  no  chance  of  moving  the 
bolt.  In  his  paper  already  alluded  to,  Mr.  Chubb 
says : — 
"  The  number  of  changes  which  may  be  efTectcd  on  the  keys  of  a  three-inch  drawer 
lock  is  Ix2x3x4x5x  0  =  720,  the  numl)er  of  ditferent  combinations  which  may  be  made 
on  the  six  steps  of  unequal  lengths,  without  altering  the  length  of  either  step.  The  height 
of  the  shortest  step  is  however  capable  of  being  reduced  20  times ;  and  each  time  of  being 
reduced,  the  720  combinations  maybe  repeated;  therefore  720x20=14,400  changes." 
By  effecting  changes  of  this  character,  therefore,  almost  any  number  of  comljinations  can  be 
produced.  The  Bramah  lock  has  been  long  celebrated,  and  most  deservedly  so.  Notwith- 
standing the  fact  that  this  lock  was  picked  by  Mr.  Hobbs  after  having  the  lock  in  his  posses- 
sion for  sixteen  day.*:,  it  appears  to  us  that  it  mo.*t  fully  justifies  the  boast  made  by  Mr.  Bramah 
in  his  ''^  Dixncrtation  on  the  ConMricction  of  Lockx.^''  "Being  confident,"  he  says,  "  that  I 
have  contrived  a  security  which  no  instrument  but  its  proper  key  can  reach,  and  which  may 
be  so  applied  as  not  only  to  defy  the  art  and  ingenuity  of  the  most  skilful  workman,  but  to 
render  the  utmost  force  ineffectual,  and  thereby  to  secure  what  is  most  valued  as  well  from 
dishonest  servants  as  from  the  midnight  ruffian,  I  think  myself  at  liberty  to  declare  (what 
nothing  but  the  discovery  of  an  infallible  remedy  would  justify  my  disclosing)  that  all  de- 
pendence on  the  inviolable  security  of  locks,  even  of  those  which  are  constructed  on  the 
ije.st  principle  of  any  in  general  use,  is  fallacious."  He  then  proceeds  to  demonstrate  the 
imperfections  of  ordinary  locks  and  to  describe  his  own  : — 

"  The  body  of  a  Bramah  lock  may  be  considered  as  formed  of  two  concentric  brass 
barrels,  the  outer  one  fixed,  and  the  inner  rotating  within  it.  The  inner  barrel  has  a  pro- 
jecting stud,  which,  while  the  barrel  is  rotating,  comes  in  contact  with  the  bolt  in  such  a 
way  as  to  shoot  or  lock  it ;  and  thus  the  stucl  serves  the  same  purpose  as  the  bit  of  an  ordi^ 
nary  key,  rendering  the  construction  of  a  bit  to  the  Bramah  key  unnecessary.  If  the  bar- 
rel can  be  made  to  rotate  to  the  right  or  left,  the  bolt  can  be  locked  or  unlocked,  and  the 
problem  is,  therefore,  how  to  insure  the  rotation  of  the  liarrel.  The  key,  which  has  a  pijjc 
or  hollow  shaft,  is  inserted  in  the  keyhole  upon  the  pin,  and  is  then  turned  round ;  but  there 
must  be  a  nice  adju.stment  of'  the  mechanism  of  the  barrel  before  this  turning  round  of  the 
key  and  the  barrel  can  be  insured.  The  barrel  has  an  external  groove  at  right  angles  to 
the  axis,  penetrating  to  a  certain  depth ;  and  it  has  also  several  internal  longitudinal  grooves 
from  end  to  end.  In  these  internal  grooves  thin  pieces  of  steel  are  able  to  .slide,  in  a  direc- 
tion parallel  with  the  axis  of  the  barrel.  A  thin  plate  of  steel,  called  the  locking  plate,  is 
screwed  in  two  portions  to  the  outer  barrel,  concentric  with  the  inner  barrel ;  and  at  the 
same  time  occupying  the  external  circular  groove  of  the  inner  barrel ;  this  plate  has  notches, 
fitted  in  number  and  size  to  receive  the  edges  of  the  slides  which  work  in  the  internal  longi- 
tudinal grooves  of  the  barrel.  If  this  were  all,  the  barrel  could  not  revolve,  because  the 
slides  are  catching  in  the  grooves  of  the  locking  plate  ;  but  each  slide  has  also  a  groove, 
corresponding  in  depth  to  the  extent  of  this  entanglement;  and  if  this  groove  be  brought 
to  the  plane  of  the  locking  plate,  the  barrel  can  be  turned,  so  far  as  respects  the  individual 
slide.  All  the  .«lides  must,  however,  be  so  adjusted,  that  their  grooves  shall  come  to  the 
same  plane  ;  but,  as  the  notch  is  cut  at  ditferent  points  in  the  lengths  of  the  several  slide.*, 
the  slides  have  to  be  pushed  in  to  different  distances  in  the  l)arrel  in  order  that  this 
juxtaposition  of  notches  may  be  insured.  This  is  effected  by  the  key,  which  has 
notches  or  clefts  at  the  end  of  the  pipe  equal  in  number  to  the  slides,  and  made  to  fit  the 
ends  of  the  slides  when  the  key  is  inserted ;  the  key  presses  each  slide,  ami  pu.«hes  it 
so  far  as  the  depth  of  its  cleft  will  permit ;  and  all  the.«e  depths  are  such  that  all  the 
slides  are  pushed  to  the  exact  position  where  their  notches  all  lie  in  the  same  plane; 
this  is  the  plane  of  the  locking  plate,  and  the  barrel  can  be  then  turned."  {Tomlinson  on 
the  Construction  of  Locks.)  In  this  work  the  details  on  con.struction  arc  given  with  great 
clearness. 

The  American  bank  locks,  especially  that  of  Messrs.  Day  and  Newall,  have  excited  much 
attention.     Their  English  patent  describes  it  thus: — 

"  The  object  of  the  present  improvements  is  the  constructing  of  locks  in  such  manner 


1 


LOCKS. 


723 


that  the  interior  arrangements,  or  the  combination  of  the  internal  movable  parts,  may  be 
changed  at  pleasure  according  to  the  form  given  to,  or  change  made  in,  the  key,  without 
the  necessity  of  arranging  the  movable  parts  of  the  lock  by  hand,  or  removing  the  lock  or 
any  part  thereof  from  the  door.  In  locks  constructed  on  this  plan,  the  key  may  be  altered 
at  pleasure  ;  and  the  act  of  locking,  or  throwing  out  the  bolt  of  the  lock,  produces  the  par- 
ticular arrangements  of  the  internal  parts,  wliich  correspond  to  that  of  tlie  key  for  the  time 
being.  While  the  same  is  locked,  this  form  is  retained  until  the  lock  is  unlocked  or  tlie 
bolt  withdrawn,  upon  which  the  internal  movable  pai'ts  return  to  their  original  posilion,  with 
reference  to  each  other ;  but  these  parts  cannot  be  made  to  assume  or  be  biought  buck  to 
their  original  position,  except  by  a  key  of  the  precise  form  and  dimensions  as  tlie  key  by 
which  they  were  made  to  assume  such  arrangement  in  the  act  of  locking.  The  key  is 
changeable  at  pleasure,  and  the  lock  receives  a  special  form  in  the  act  of  locking  according 
to  the  key  employed,  and  retains  tliat  form  until,  in  the  act  of  unlocking  by  the  same  key,  it 
resumes  its  original  or  unlocked  state.  The  lock  is  again  changeable  at  pleasure,  simply  by 
altering  the  arrangement  of  tlie  movable  bits  of  the  key :  and  the  key  may  be  changed  to 
any  one  of  the  forms  within  the  number  of  permutations  of  which  the  parts  are  susceptible." 
—April  15,  1851. 

Mr.  Hobbs,  who  has  been  carrying  out  the  manufacture  of  American  locks  in  this  coun- 
try has  introduced  an  inexpensive  lock,  which  he  calls  a  protector  lock.  The  following 
description  is  borrowed  from  Mr.  Charles  Tomlinson's  Treatise  on  the  Construction  of 
Locks : — 

"  When  the  American  locks  became  known  in  England,  Mr.  Hobbs  undertook  the  super- 
intendence of  their  manufacture,  and  their  introduction  into  the  commercial  world.  Such 
a  lock  as  that  just  described  must  necessarily  be  a  complex  piece  of  mechanism  ;  it  is  in- 
tend^'d  for  use  in  the  doors  of  receptacles  containing  property  of  great  value,  and  the  aim 
has  been  to  balfle  all  the  methods  at  piescnt  known  of  picking  locks,  by  a  combination  of 
mechanism  necessarily  elaborate.  Such  a  lock  must  of  necessity  be  costly ;  but  in  order 
to  supply  the  demand  for  a  small  lock  at  moderate  price,  Mr.  Ilobbs  has  intioduced  what  he 
calls  a  protector  lock.  This  is  a  modification  of  the  ordinary  six-tumbler  lock.  It  bears  an 
affinity  to  tlie  lock  of  Messrs.  Day  and  Newall,  inasmuch  as  it  is  an  attempt  to  introduce  the 
same  principle  of  security  against  picking,  while  avoiding  the  complexity  of  the  change- 
able lock.  The  distinction  which  Mr.  Ilobbs  has  made  between  secure  and  insecure  locks 
will  be  understood  from  tlie  following  proposition,  viz.  '  that  whenever  the  parts  of  a  lock 
which  come  in  cont^^Jt  with  the  key  are  so  affected  by  any  pressure  applied  to  the  bolt,  or 
to  that  portion  of  the  lock  by  which  the  bolt  is  withdrawn,  as  to  indicate  the  points  of  re- 
sistance to  the  withdrawal  of  the  l)olt,  such  a  lock  can  be  picked.'  Fir/.  417  exhibits  the 
internal  mechanism  of  this  new  patent  lock.  It  contains  the  usual  contrivances  of  tumblers 
and  springs,  with  a  key  cut  into  steps  to  suit  the  different  heights  to  which  the  tumblers 
must  be  raised.  The  key  is  shown  separately  injlr/.  418.  But  tliere  is  a  small  additional 
piece  of  mechanism,  in  which  the  tumbler  stump  shown  at  s  in  fi.qit.  416  and  417  is  attached ; 
which  piece  is  intended  to  work  under  or  behind  the  bolt  of  the  lock.     Injif/.  417  6  is  the 


417 


416 


bolt ;  t  t  is  the  front  or  foremost  of  the  range  of  six  tumblers,  each  of  which  has  the  usual 
slot  and  notches.  In  other  tumbler-locks  the  stump  or  stud  which  moves  along  these  slots 
is  riveted  to  the  bolt,  in  such  matin  m-  that,  if  any  pressure  be  applied  in  an  attempt  to  with- 
draw the  bolt,  the  stump  becomes  pressed  against  the  edges  of  the  tumblers,  ami  bites  or 
binds  against  them.  How  far  tlui.-  lilting  facilitates  the  |)ickiiig  of  a  lock  will  be  shown 
t'uith(  r  on  ;  but  it  will  suflicc  here  to  say,  that  the  niovalile  action  given  to  the  stump  in 
the  Ho!)l)S  lock  transfers  the  pressure  to  another  ()uarter.  The  stump  s  is  riveted  to  a 
peculiarly-shaped  piece  of  metal  h  p,  {Jig.  416,)  the  hole  in  the  centre  of  which  fits  upon 


724  LOCOMOTIVE  ENGINES. 

a  centre  or  pin  in  a  recess  formed  at  the  back  of  the  bolt ;  the  piece  moves  easily  on  its 
centre,  but  is  prevented  from  so  doing  spontaneously  by  a  small  binding  spring.  The  mode 
in  which  this  small  movable  piece  takes  part  in  the  action  of  the  lock  is  as  follows :  when 
the  proper  key  is  applied  in  the  usual  way,  the  tumblers  are  all  raised  to  the  proper  heights 
for  allowing  the  stump  to  pa?s  horizontally  through  the  gating ;  but  should  there  be  an 
attempt  made,  either  by  a  false  key  or  by  any  other  instrument,  to  withdraw  the  bolt  before 
the  tumblers  are  properly  raised,  the  stump  becomes  an  obstacle.  Meeting  with  an  obstruc- 
tion to  its  passage,  the  stump  turns  the  piece  to  which  it  is  attached  on  its  centre,  and  moves 
the  arm  of  the  piece  p  so  that  it  shall  come  into  contact  with  a  stud  riveted  into  the  case  of 
the  lock  ;  and  in  this  position  there  is  a  firm  resistance  against  the  withdrawal  of  the  bolt. 
The  tumblers  are  at  the  same  moment  released  from  the  pressure  of  the  stump.  There  is  a 
dog  or  lever  d,  which  catches  into  the  top  of  the  bolt,  and  thereby  serves  as  an  additional 
security  against  its  being  forced  back.  At  k  is  the  drill-pin  on  which  the  pipe  of  the  key 
works ;  and  )•  is  a  metal  piece  on  which  the  tumblers  rest  when  the  key  is  not  operating 
upon  them. 

Another  lock,  patented  by  Mr.  Ilobbs  in  1852,  has  for  its  object  the  absolute  closing  of 
the  key-hole  during  the  process  of  locking.  The  key  does  not  work  or  turn  on  its  o^ni 
centre,  but  occupies  a  small  cell  or  chamber  in  a  revolving  cylinder,  which  is  turned  l)y  a 
fixed  handle.  The  bit  of  the  movable  key  is  entirely  separable  from  the  shaft  or  stem,  into 
which  it  is  screwed,  and  may  be  detached  by  turning  round  a  small  milled  headed  thumb- 
screw. The  key  is  placed  in  the  key-hole  in  the  usual  way,  but  it  cannot  turn  ;  its  circular 
movement  round  the  stem  as  an  axis  is  prevented  by  the  internal  mechanism  of  the  lock ; 
it  is  left  in  the  key-hole,  and  the  stem  is  detached  from  it  by  unscrewing.  By  turning  the 
handle,  the  key-bit,  which  is  left  in  the  chamber  of  the  cylinder,  is  brought  into  contact 
with  the  works  of  the  lock,  so  as  to  shoot  and  withdraw  the  bolt.  This  revolution  may  take 
place  whether  the  bit  of  the  movable  key  occupy  its  little  cell  in  the  plate  or  not ;  only 
with  this  difference — that  if  the  bit  be  not  in  the  lock,  the  plate  revolves  without  acting 
upon  any  of  the  tumblers  ;  but  if  the  bit  be  in  its  place,  it  raises  the  tumblers  in  the  proper 
way  for  shooting  or  withdrawing  the  bolt.  It  will  be  understood  that  there  is  only  one  key- 
hole, namely,  that  through  which  the  divisible  key  is  inserted ;  the  other  handle  or  fixed 
key  working  through  a  hole  in  the  cover  of  the  lock  only  just  large  enough  to  receive  it, 
and  not  being  removable  from  the  lock.  As  soon  as  the  plate  turns  round  so  far  as  to 
enable  the  key-bit  to  act  upon  the  tumblers,  the  key-holes  become  entirely  closed  by  the 
plate  itself,  so  that  the  actual  locking  is  effected  at  the  very  time  when  all  access  to  the  in- 
terior through  the  key-hole  is  cut  off.  When  the  bolt  has  been  shot,  the  plate  comes  round 
to  its  original  position,  it  uncovers  the  key-hole,  and  exhibits  the  key-bit  occupying  the  little 
cell  into  which  it  had  been  dropped ;  the  stem  is  then  to  be  screwed  into  the  bit,  and 
the  latter  withdrawn.  It  is  one  consequence  of  this  arrangement,  that  the  key  has  to 
be  screwed  and  unscrewed  when  used ;  but  through  this  arrangement  the  keyhole 
becomes  a  sealed  book  to  one  who  has  not  the  right  key.  Nothing  can  be  moved,  pro- 
vided the  bit  and  stem  of  the  key  be  both  left  in;  but  by  leaving  in  the  lock  the 
former  without  the  latter,  the  plate  can  rotate,  the  tumblers  can  be  lifted,  and  the  bolt  can 
be  shot. 

LOCOMOTIVE  EXGIXES.  The  character  of  this  work  excludes  any  special  notice  of 
a  subject  so  entirely  belonging  to  a  work  on  Mechanical  Engineering,  as  that  of  locomotive 
engines.  Nevertheless,  since  so  much  has  lately  been  said  and  written  on  the  question  of 
employing  coal  on  our  railways  instead  of  coke,  we  are  induced  to  introduce  the  following 
arrangement,  which  secures  combustion  without  smoke.  It  is  known  as  Dumery's  plan. 
The  annexed  drawing,  {fg.  419,)  is  a  section  of  a  locomotive  cugine,  used  on  the  Chalons 
Railway.  The  coal  is  thrown  into  the  side  pipes  a  b,  which  open  below  the  platform  on 
which  the  engine-man  stands.  These  pipes  conduct  the  coal  by  their  own  gravity  to  the 
lower  level  of  the  bars,  where  they  are  thrust  in  the  direction  of  the  arrows  c  n,  by  a  kind 
of  comb,  or  rotating  pin,  which  in  its  rotation  around  the  axle  e,  forces  the  coal  to  ascend 
the  incline  forward  by  the  bars. 

This  then  takes  place,  the  coal  in  its  rude  state  (i.  e.  ns  it  comes  from  the  pit)  coming 
from  below,  finds  itself  immediately  in  contact  with  the  tire,  which  induces  an  escape  of  the 
gases,  and  with  the  pure  air  which  permits  their  combustion  to  take  place  in  the  only  con- 
dition in  which  it  is  possible,  i.  e.  in  small  jets,  which  facilitate  the  complete  oxygenation  of 
all  the  parts. 

The  gases  once  produced  and  burnt,  the  rest  of  the  operation  scarcely  needs  explanation. 
The  coal  is  converted  into  coke,  and  finishes  its  passage  while  burning  under  this  form  :  and 
as  the  rorafainder  of  the  solids,  cinders  and  slag,  (or  clinkers,)  are  not  al)andoned  by  the  fire 
until  after  all  that  it  contains  of  a  combustible  nature  has  disappeared,  all  the  detritus 
(refuse)  and  dust,  cinders,  ashes,  &c.,  are  deposited  on  the  surface  {soimnet)  of  the  bars  in 
the  centre  of  the  fire,  where  they  would  offer  an  obstruction  similar  to  that  found  in  ordinary 
fire-places,  if  the  inventor  had  not  taken  care  to  make  the  bars  oscillate  from  the  centre  Ijy 
a  small  movement.     Thus,  when  a  drop  of  slag  approaches  the  bars,  it  is  disi)laced  and 


LUCIFER  MATCHES. 


726 


thrown  out  (by  the  opening  of  the  bars)  in  small  particles.  This  accessory  arrangement 
apparently  possesses  great  advantages  for  a  locomotive  in  saving  the  trouble  of  scraping  and 
cleaning  the  bars. 

So  if,  as  in  an  ordinary  fire,  coke  or 
anthracite,  &c.,  be  burnt,  the  combustion 
would  be  very  complete.  Air  fresh  from 
the  ash-pan,  in  passing  over  the  combust- 
ible, would  be  converted  into  carbonic 
acid,  i.  e.  into  a  gas  which  is  unfit  for 
further  combustion.  But  if  in  the  place 
of  coke  or  anthracite,  &c.,  we  use  smoke- 
producing  coal,  i.  e.  composed  of  two 
dements,  one  solid,  the  other  gaseous, 
this  result  follows :  The  combustible 
gases  disengaging  themselves  (in  this 
case  above  the  combustible)  in  a  state  of 
ignition,  the  air  which  will  become  vitia- 
ted in  traversing  the  first  bed  of  the  solid 
combustible,  will  be  found  unable  to  effect 
the  combustion  of  the  gases  which  escape 
above  the  fire,  and  smoke  will  make  its 
appearance,  i.  e.  the  combustion  will  be 
incomplete  and  imperfect.  This  is  what 
takes  place  with  combustion  of  coal  in 
ordinary  fire-places. 

There  are  also  other  causes  which 
contribute  to  the  imperfection  of  this 
result.  These  gases  in  disengaging 
themselves  do  not  always  acquire  a  tem- 
perature sufficiently  high  to  produce 
flame,  and  the  volume  of  combustible 
gas  is  almost  ahv.ays  too  considerable  to 
allow  of  its  being  sufficiently  penetrated 
witli  oxygen.  These  are  some  of  the 
radical  vices  wliich  M.  Dumery  has  re- 
moved in  thus  placing  the  gases  at  once 
in  the  condition  best  suited  ibr  their  combustion.  Tliis  process  is  admirable,  since,  wi;h- 
out  any  preparation,  it  allows  of  coal  being  burnt  with  as  much  facility  as  coke,  and 
saves  till!  great  expense  of  converting  coal  into  coke. 

LODE,  {a  mining  term).  A  mineral  lode,  or  a  mineral  vein,  is  the  name  given  to  a 
fissure  in  the  crust  of  the  earth  which  has  been  filled  in  with  metalliferous  matter.  The 
miner  gives  the  same  name  lode  to  a  fissure  filled  with  quartz,  carbonate  of  lime,  &c.,  but 
tlien  he  says  the  lode  is  not  "  mineralized,"  confining  the  word  mineral  to  metalliferous 
matter. 

The  term  vei}i  has  frequently  led  to  the  idea  that  expresses  the  condition  of  sonic- 
tliing  analogous  to  the  blood-vessels  of  the  animal  body,  to  which  a  lode  has  not  in  tlie 
remotest  degree  any  resemblance.  During  some  primary  convulsions,  the  crust  of  the 
earth  has  been  cracked,  these  fissures  having,  of  course,  some  special  relation  to  the  di- 
rection of  the  force  which  produced  them.  These  cracks  have  during  ages  of  sub- 
mergence been  filled  in,  according  to  some  law  of  polarity  with  mineral  matter,  the 
character  of  the  lode  having  generally  some  special  relation  to  its  direction.  See 
Mi.\i.\(J,  &c. 

LUCIFER  MATCHES.  The  importance  of  this  manufacture  has  been  shown  by 
Mr.  Tomlinson  in  a  conmiunication  made  by  that  gentleman  to  the  journal  of  the 
Society  of  Arts. 

"  It  has  been  estimated,"  he  says,  "  that  the  English  and  French  manufacturers  of 
phosphorus  are  now  producing  :it  the  rate  of  300,000  lbs.  of  common  phosphorus  per 
annum,  nearly  the  whole  of  which  is  consumed  in  making  lucifcr  matches.  In  com- 
pounding the  emulsion  for  tipping  the  matches,  the  German  manufacturers  make  three 
pounds  of  phosphorus  suffice  for  five  or  six  millions  of  matches.  If  we  suppose  only  one 
lialf  of  the  French  and  English  annual  product  of  phosphorus  to  be  employed  in  making 
matches,  tliis  will  give  us  250,000,0()0,00(»  of  matches  as  the  annual  product  consequent 
on  the  consumption  of  one-iialf  of  the  French  and  English  phosphorus.  We  need  not 
suppose  this  to  be  an  exaggerated  statement,  when  we  consider  the  daily  product  of 
some  of  our  match  manufactories.  I  lately  had  occasion  to  describe  the  processes  of  a 
London  factory,  which  produces  2,5U(),000  matches  daily.  For  this  purpose,  14  3- 
inch  planks  arc  cut  up;  each  plank  produces  30  blocks;  each  block,  of  the  dimensions 


726 


LUMACHELLE. 


of  11  inches  long,  4|  inches  wide,  and  3  inches  thick,  produces  ICO  slices,  each  slice  31 
splints,  each  splint  2  matches :  thus  we  have — 14  x  30  x  100  x  31  x  2  =  2,604,000  matches 
as  the  day's  work  of  a  single  factory  in  London.  At  Messrs.  Dixon's  factory  near  Man- 
chester, from  6,000,000  to  ',t,OnO, ()()()  of  matches  are  produced  daily." — loinlinson. 

A  ^^  Safe/;/ Lucifer  M'llch"  as  it  is  called,  lias  been  manufactured  in  Sweden.  A 
p.atent  was  obtained  in  that  country  by  Messrs.  Bryant  and  May,  for  this  match.  Its 
peculiarity  consists  iu  the  division  of  the  combustible  ingredients  of  the  Inciter  between 
the  match  and  the  friction  paper.  In  the  ordinary  luciftr,  the  phosphorus,  sulphur,  and 
chlorate  of  potash  or  nitre,  are  all  together  on  the  match,  which  ignites  when  rubbed 
against  any  rough  substance.  In  the  Swedish  matches  these  materials  are  so  divided  that 
the  phosphorus  is  placed  on  the  sand-paper,  whilst  the  sulphur  and  a  minimum  amount 
of  chlorate  or  nitre  of  potash  is  placed  on  the  match.  In  viitue  of  this  arrangement  it 
is  only  when  the  phosphorized  sand-paper  and  the  sulplnnized  match  come  in  contact 
with  each  other  that  the  ignition  occurs.  Neither  match  nor  sand-paper,  singly,  takes 
fire  by  moderate  friction  against  a  rough  surface. 

The  composition  of  lucifer  matches  varies  greatly,  as  it  regards  the  proportions  of  the 
m;\terials  employed.  In  principle  they  are,  however,  as  wc  have  described  thcin  above, 
every  thing  depending  on  the  ignition  of  the  phosphorus,  and  the  perfection  of  a  lucifer 
match  is  in  tipping  the  match  with  a  composition  which  will  ignite  quietly  upon  attrition 
against  any  rough  surf.ice,  but  which  is  not  liable  to  ignition  by  such  pressure  as  it  may 
be  subjected4o  under  the  ordinary  condition  of  keeping  in  closed  bo.xes. 

The  prepiiration  of  lucifer  matches  has  been  attended  with  much  human  suffering. 
Every  persou  engaged  in  a  factory  of  this  kind  is  more  or  less  exposed  to  the  fumes  of 
phosphorus,  and  this  exposure  produces  a  disease  which  has  been  thus  described  by  Mr. 
Harrison,  in  the  Quarttrh/  Jtmrnal  of  Medical  Science: — "This  disease,"  he  says,  "is  of 
so  insidious  a  nature  that  it  is  at  first  supposed  to  be  common  toothache,  and  a  most 
serious  disease  of  the  jaws  is  produced  before  the  patient  is  fully  aware  of  his  condition. 
Tiie  disease  grailually  creeps  on,  until  the  sufferer  becomes  a  miserable  and  loathsome 
o^'jeit,  spending  the  best  period  of  his  life  in  the  wards  of  a  public  hospital.  Many- 
patients  have  died  of  the  disease  ;  many,  unable  to  open  their  jaws,  have  lingered  with 
carious  and  necrosed  bones  ;  others  have  suflered  dreadful  mutilations  from  surgical 
operations,  considering  themselves  happy  to  escape  with  the  loss  of  the  greater  portion 
of  the  lower  jaw." 

By  the  introduction  of  an  amorphous  phosphorus  discovered  by  M.  Schrijtter,  which 
is  in  nearly  all  respects  unlike  the  ordinary  phosphorus,  feut  which  answers  exceedingly 
well  for  the  manufacture  of  hicifcr  matches,  this  disease  is  prevented,  the  manufactory  is 
rendered  more  healthy,  and  the  boxes  of  matches  themselves  less  dangerous.  See  Pnos- 
PHOuus.     In  1857  our  imports  and  exports  were — 


-Wood,  No, 
Vesta  of  Wax 


Imports — Lncifcrs- 

Exports — Lncifers — Wood  (C'ubic  Feet) 
"  Vesta  of  Wax,  No. 


155,153     - 

-£29,091 

17,30.5,210     - 

-      1,450 

10,628     - 

-      1,993 

5,604,480     - 

47 

'bril- 


LUMACITELLE,  or  Fire  Marble.     This  is  a  dark  brown  shelly  marble,  having 
liant  fire  or  chatoyant  reflections  from  within. — See  MAnnti;. 

LUNAR  CAUSTIC.  A  name  for  nitrate  of  silver,  when  fused  and  run  into  cylindrical 
moulds. 

LUSTRING,  sometimes  spelled  and  pronounced  Lutestring;  a  peculiar  shining  silk. 

LUTEOLINE,  is  the  coloring  princijile  of  the  weld,  (Hceda  lutcula,)  a  slender  plant 
growing  to  the  height  of  about  three  feet,  and  cultivated  for  the  use  of  dyers.  When 
ripe  it  is  cut  and  dried. 

Chevreul  was  the  first  to  separate  the  lutcoline  ;  it  is  extracted  from  the  weld  by 
boiling  water,  and  when  this  solution  is  concentrated  and  allowed  to  cool,  the  luteoline 
separates ;  it  is  then  collected,  dried,  and  submitted  to  sublimation,  when  it  is  condensed 
in  yellow  needles. 

It  is  v.dued  for  its  durability,  and  is  used  as  a  yellow  dye,  on  cottons  principally,  and 
also  on  silks,  but  is  little  used  at  jircsent.  It  was  formerly  used  by  paper-hanging  manu- 
facturers, to  form  a  yellow  jjiguient,  but  has  been  entirely  superseded  for  that  purpose,  by 
quercitron  hark  and  Pcrdan  hcrrics.  It  unites  with  acids  and  alkalies,  the  former  mak- 
ing the  color  paler,  and  the  latter  heightening  the  color.  The  compound  which  it  forms 
with  potash  is  of  a  golden  color,  becoming  greenish  when  exposed  to  the  air,  by  absorp- 
tion of  oxygen,  and  at  length  becomes  red. 

It  forms  yellow  compounds  with  alum,  protochloride  of  tin,  and  acetate  of  lead  ;  with 
the  salts  of  iron  it  produces  a  blackish  gray  precipitate,  and  with  sulphate  of  copper  a 
greenish  brown  precipitate. 

It  is  readily  soluble  in  alcohol  and  ether,  but  sparingly  so  in  water. — H.  K.  B, 


MADDER.  727 


M 


MADDER,  {Garance,  Fr.  ;  Krapp,  Farbcrrothe,  Germ.,)  a  substance  very  extensively 
used  in  dyeing,  is  the  root  of  the  liubia  tinctorurn,  Linn.  It  is  employed  for  the  pro- 
duction of  a  variety  of  colors,  such  as  red,  pink,  purple,  black,  and  chocolate. 

The  Levant  madder,  usually  called  Turkey  roots,  is  considered  to  be  the  finest  quality 
imported  into  this  country.  It  comes  to  us  from  Smyrna,  and  consists  of  the  whole  roots 
broken  into  small  pieces  and  packed  in  bales.  It  is  ground  as  it  is,  without  any  attempt 
being  made  to  separate  the  different  portions  of  the  root ;  and  has  then  the  appearance 
of  a  coarse  dark  reddish-brown  powder.  It  is  employed  chiefly  for  the  purpose  of  dye- 
ing the  finer  purples  on  calico.  Next  to  this  comes  the  madder  of  Avignon,  of  which 
two  varieties  are  distinguished  in  commerce,  viz.  :  Paluds  and  rosie.  The  first,  which  is 
the  finest,  owes  its  name  to  the  district  in  which  it  is  grown,  consisting  of  a  small  tract 
of  reclaimed  marsh-land  in  the  ncighborliood  of  Avignon.  Avignon  madder  is  consid- 
ered to  be  the  best  adapted  for  dyeing  pink.  It  has  the  appearance,  as  imported  into 
this  country,  of  a  fine,  pale  yellowish-brown  or  reddish-brown  powder.  The  paler  color, 
as  compared  with  that  of  ground  roots,  is  owing  to  the  partial  separation  of  the  external 
or  cellular  portion  of  the  root  during  the  process  of  grinding,  as  practised  in  France. 
The  madders  of  Alsace,  Holland,  and  Naples  are  richer  in  coloring  matter  than  the  two 
preceding  kinds,  but  they  yield  less  permanent  dyes,  and  are  therefore  only  employed 
for  colors  which  require  little  treatment  with  soap,  and  other  purifying  agents  after  dye- 
ing. Of  late  years,  indeed,  the  employment  of  garancine,  a  preparation  of  madder,  in 
the  place  of  these  lower  descriptions,  has  become  very  general. 

All  kinds  of  madder  have  a  peculiar,  indescribable  smell,  and  a  taste  between  bitter  and 
sweet.  Their  color  varies  extremely,  being  sometimes  yellow,  sometimes  orange,  red,  red- 
dish-brown, or  brown.  They  are  all  more  or  less  hygroscopic,  so  that  even  when  closely 
packed  in  casks  in  a  state  of  powder,  they  slowly  attract  moisture,  increase  in  weight,  and 
at  length  lose  their  pulverulent  condition,  and  form  a  firm,  coherent  mass.  This  change 
takes  place  to  a  greater  extent  with  Alsace  and  Dutch  madders,  than  with  those  of  Avig- 
non. Madder  which  has  undergone  this  change  is  called  by  the  French  garance  grappie. 
It  is  probable  that  some  process  of  fermentation  goes  on  at  the  same  time,  for  madder  that 
is  kept  in  casks  in  a  dry  place,  and  as  much  out  of  contact  with  the  air  as  possible,  is  found 
constantly  to  improve  in  quality  for  a  certain  length  of  time,  after  which  it  again  deterio- 
rates. Some  kinds  of  madder,  especially  those  of  Alsace  and  Holland,  when  mixed  with 
water  and  left  to  stand  a  short  time,  give  a  thick  coagulum  or  jelly,  which  does  not  take 
place  to  the  same  degree  w-ith  Avignon  madder.  The  madder  of  Avignon  contains  so  much 
carbonate  of  lime  as  to  effervesce  with  acids.  The  herbaceous  parts  of  the  plant,  when 
given  as  fodder  to  cattle,  are  found  to  communicate  a  red  color  to  their  bones — a_  circum- 
stance which  was  first  observed  about  a  hundred  years  ago,  and  has  been  employed  by 
physiologists  to  deternune  the  manner  and  rate  of  growth  of  bone. 

There  exists  no  certain  means  of  accurately  ascertaining  the  intrinsic  value  of  any  sam- 
ple of  madder,  except  that  of  dyeing  a  certain  quantity  of  mordanted  calico  with  a  weighed 
(]uantity  of  the  sample,  and  comparing  the  depth  and  solidity  of  the  colors  with  those  pro- 
duced by  the  same  weight  of  another  sample  of  known  quality,  and  even  this  method  may 
lead  to  uncertain  results,  if  practised  on  too  small  a  scale.  The  Paluds,  which  is  the  most 
esteemed  of  the  Avignon  madders,  has  a  dark  red  hue,  whereas  the  other  kinds  have  natu- 
rally a  yellow,  reddish-yellow  or  brownish-yellow  color.  Nevertheless,  means  have  been 
devised  of  communicating  to  the  latter  the  desired  reddish  tinge,  which,  therefore,  no  longer 
serves  as  a  test.  A  method  formerly  employed  to  ascertain  the  comparative  value  of  a 
number  of  samples  of  madder  consisted  in  placing  a  small  (piantity  of  each  sample  on  a 
slate,  pressing  tlie  heaps  flat  with  some  hard  body,  and  then  taking  tiiein  to  a  cellar  or  other 
damp  place.  After  10  or  12  hours  they  were  examined,  and  that  which  had  acciuired  the 
deepest  color,  and  increased  the  most  in  volume,  was  considered  the  best.  This  method 
led,  however,  to  so  many  frauds  on  the  part  of  the  dealer,  for  the  purpose  of  producing  the 
desired  effect,  that  it  is  no  longer  resorted  to.  Madder  is  sometimes  adulterated  with  .sand, 
clay,  brick-dust,  ochre,  saw-dust,  bran,  oak-bark,  l()gwood  and  other  dye-woods,  sumac  and 
quercitron  bark.  Some  of  these  additions  are  dillicult  to  detect.  Such  as  contain  tannin 
may  be  discovered  by  the  usual  tests,  since  madder  contains  naturally  no  taiuiin.  If  the 
material  used  for  adulteration  be  of  mineral  nature,  its  presence  may  be  discovered  by  in- 
cinerating a  weighed  quantity  of  the  sample.  If  the  quantity  of  ash  which  is  left  exceeds 
10  per  cent,  of  the  mati'rial  employed,  adulteration  may  be  suspected.  The  ash  obtained 
by  incinerating  pure  madder  consists  of  the  carbonates,  sulphates,  and  phos[)hates  of  potash 
and  soda,  chloride  of  potassium,  carbonate  and  phosphate  of  lime,  phosphate  of  magnesia, 
oxide  of  iron  and  silica.  If  a  considerable  amount  of  other  material  constituent  is  found, 
it  is  certainly  due  to  adulteration. 


728 


MADDER. 


There  is  probably  no  subject  connected  with  the  art  of  dyeing  which  has  given  rise  to 
so  much  discussion  as  the  composition  of  madder,  and  the  chemical  nature  of  the  coloring 
matters  to  which  it  owes  its  valuable  properties.  The  subject  has  engaged  the  attention  of 
a  number  of  chemists,  whose  labors,  extending  over  a  period  of  about  filty  years,  have 
thrown  considerable  light  on  it.  Nevertheless,  the  conclusions  at  which  they  have  severally 
arrived  do  not  perfectly  agree  with  one  another,  nor  with  the  views  entertained  by  the  most 
intelligent  of  those  practically  engaged  in  madder  dyeing.  The  older  investigators  supposed 
that  madder  contained  two  coloring  matters,  one  of  which  was  tawny,  and  the  other  red. 
Robiquet  was  the  first  chemist  who  asserted  that  it  contained  two  distinct  red  coloring  mat- 
ters, both  of  which  contributed  to  the  production  of  the  dyes  for  which  madder  is  em- 
ployed ;  and  his  views,  though  they  were  at  the  time  of  their  promulgation  strongly  objected 
to  by  some  of  the  most  eminent  French  dyers  and  calico  printers,  still  offer  probably  the 
best  means  of  explaining  some  of  the  phenomena  occurring  during  the  process  of  madder 
dyeing.  The  two  red  coloring  matters  discovered  by  Robiipict  were  named  by  him  Aika- 
riiie  and  Purpurine,  and  these  names  they  still  retain.  Several  crystallized  yellow  color- 
ing matters  have  been  discovered  by  other  chemists  ;  but  the  only  one  which  exists  ready- 
formed  in  the  madder  of  commerce  is  the  Rnbiacinc  of  Schunck,  and  this  substance  may 
also  be  taken  as  the  type  of  the  whole  class,  the  members  of  which  possess  very  similar 
properties.  Among  the  other  organic  substances  obtained  by  different  chemists  from  mad- 
der, two  resinous  coloring  matters,  sugar,  a  bitter  principle,  a  i)cculiar  extractive  matter, 
pectin,  a  fermentative  nitrogenous  substance,  and  malic,  citric,  and  oxalic  acids,  may  be 
mentioned. 

When  madder  is  extracted  with  boiling  water,  a  dark  brown  muddy  liquid,  having  a 
taste  between  bitter  and  sweet,  is  obtained.  On  adding  a  small  quantity  of  an  acid  to  this 
liquid,  a  dark  brown  precipitate  is  produced,  while  the  supernatant  liquid  becomes  clear, 
and  now  appears  of  a  bright  yellow  color.  The  precipitate  consists  of  alizarine,  purpurine, 
rubiacine,  the  two  resinous  coloring  matters,  pectic  acid,  oxidized  extractive  matter,  and  a 
peculiar  nitrogenous  substance.  The  liquid  filtered  from  this  precipitate  contains  the  bitter 
principle  and  the  extractive  matter  of  madder,  as  well  as  sugar  and  salts  of  potash,  lime 
and  magnesia.  No  starch,  gum,  or  tannin,  can  be  detected  in  the  watery  extract.  After 
the  madder  has  been  completely  exhausted  with  boiling  water,  it  appears  of  a  dull  red  color. 
It  still  contains  a  quantity  of  coloring  matter,  which  cannot,  however,  be  extracted  with 
hot  water,  or  even  alkalies,  since  it  exists  in  a  state  of  combination  with  lime  and  other 
bases,  forming  compounds  which  are  insoluljle  in  those  menstrua.  If,  however,  the  residue 
be  treated  with  boiling  dilute  muriatic  acid,  the  latter  dissolves  a  quantity  of  lime,  magne- 
sia, alumina,  and  peroxide  of  iron,  as  well  as  some  phosphate  and  oxalate  of  lime,  which 
may  be  discovered  in  the  filtered  liquid ;  and  if  the  remainder,  after  being  well  washed,  be 
treated  with  caustic  alkali,  a  dark  red  liquid  is  obtained,  which  gives  with  acids  a  dark  red- 
dish-brown precipitate  consisting  of  alizarine,  purpurine,  rubiacine,  resin,  and  pectic  acid. 
That  portion  of  the  madder  left  after  treatment  with  hot  water,  acids,  and  alkalies,  consists 
almost  entirely  of  woody  fibre. 

A  short  description  of  some  of  the  substances  just  mentioned  will  not  be  out  of  place 
here,  as  it  may  assist  in  rendering  the  process  of  dyeing  with  madder  more  intelligible. 

The  most  important  of  these  substances  is  alizarine,  since  it  forms  the  basis  of  all  the 
finer  and  more  permanent  dyes  produced  by  madder.  The  matihc  coloranfe  rovge  of  Per- 
soz  and  the  madkr-red  of  Runge  also  consist  essentially  of  alizarine,  mixed  with  some  im- 
purities. Robi(iuet  first  obtained  it  in  the  form  of  a  crystalline  sublimate,  by  extracting 
madder  with  cold  water,  allowing  the  liquid  to  gelatinize,  treating  the  jelly  with  alcohol, 
evaporating  the  alcoholic  li(iuid  to  dryness  and  heating  the  residue  ;  and  since  the  applica- 
tion of  heat  seemed  to  be  an  essential  part  of  this  process,  it  was  for  a  long  time  doubted 
whether  alizarine  was  contained  as  such  in  madder,  and  was  not  a  product  of  decomposition 
of  some  other  body.  It  was  proved,  however,  by  the  experiments  of  Schunck,  that  it  docs 
in  reality  pre-exist  in  the  ordinary  madder  of  commerce,  though  not  in  the  fresh  root  when 
just  taken  out  of  the  ground.  It  has  the  following  properties  : — It  crystallizes  in  long, 
transparent,  lustrous,  yellowish-red  needles.  These  needles,  when  heated  to  212°  F.,  lose 
their  water  of  crystallization  and  become  opaque.  At  about  420"  F.  alizarine  begins  to 
sublime,  and  if  carefully  heated  may  be  almost  entirely  volatilized,  only  a  little  charcoal 
being  left  behind.  The'  sublimate  obtained  by  collecting  the  vapors  consists  of  long,  bril- 
liant, transparent,  oratige-colorcd  crystals,  which  are  pure  anhydrous  alizarine.  If  madder, 
or  any  preparation  or  extract  of  madder,  be  heated  to  the  same  temperature,  a  sulilimate 
of  al  zarine  is  also  obtained,  but  the  crystals  are  then  generally  contaminated  with  drops  of 
empyreumatic  oil,  produced  by  the  decomposition  of  other  constituents  of  the  root.  This 
oily  matter  may,  according  to  Robiquet,  be  removed  by  washing  the  crystals  with  a  little 
cold  alcohol.  Alizarine  is  almost  insoluble  in  cold  water.  It  is  only  slightly  soluble  in 
boiling  water,  and  is  deposited,  on  the  solution  cooling,  in  yellow  crystalline  flocks.  When 
the  water  contains  large  quantities  of  acid  or  salt.^  in  solution,  it  dissolves  very  little  aliza- 
rine, even  in  boiling.     The  color  of  the  solution  is  yellowish  when  it  is  quite  free  from 


MADDER.  729 

alkalies  or  alkaline  earths.  Alizarine  dissolves  much  more  readily  in  alcohol  and  ether  than 
in  water;  the  solutions  have  a  deep  yellow  color.  Alizarine  is  decomposed  by  chlorine, 
and  converted  into  a  colorless  product.  It  is  also  decomposed  by  boiling  nitric  acid,  the 
product  being  a  colorless,  crystallized  acid,  jMlialic  acid,  the  same  that  is  formed  by  the 
action  of  nitric  acid  on  naphthaline.  Alizarine  dissolves  in  concentrated  sulphuric  acid, 
yielding  a  yellow  solution,  which  may  be  heated  to  the  boiling  point  without  changing  color 
and  without  any  decomposition  of  the  alizarine,  which  is  precipitated  unchanged  on  the 
addition  of  water.  Alizarine  dissolves  in  caustic  alkalies  with  a  splendid  purple  or  violet 
color,  which  remains  unchanged  on  exposure  of  the  solutions  to  the  air.  The  ammoniacal 
solution,  however,  loses  its  ammonia  entirely  on  being  left  to  stand  in  an  open  vessel,  and 
deposits  its  alizarine  in  the  form  of  shining  prismatic  crystals,  or  of  a  crystalline  crust. 
The  alkaline  solutions  give  with  solutions  of  lime  and  baryta  salts,  precipitates  of  a  beautiful 
purple  color,  with  alumina  salts  a  red,  with  iron  salts  a  purple  precipitate,  and  with  most 
of  the  salts  of  metallic  oxides  precipitates  of  various  shades  of  purple.  The  affinity  of 
alizarine  for  alumina  is  so  great,  that  if  the  compound  of  the  two  bodies  be  treated  with 
boiling  caustic  potash  lye,  it  merely  changes  its  color  from  red  to  purple,  without  being 
decomposed.  Alizarine  is  not  more  soluble  in  boiling  alum  liquor  than  in  boiling 
water.  The  chemical  formula  of  anhydrous  alizarine  is  probably  C14H5O4,  and  100  parts 
contain  therefore  by  calculation  C9'42  of  carbon,  413  of  hytlrogen,  and  26'45  of  oxygen. 

If  alizarine  in  a  finely  divided,  or,  what  is  still  better,  in  a  freshly  precipitated  state,  be 
suspended  in  distilled  water,  and  a  piece  of  calico  printed  with  alumina  and  iron  mordants 
of  different  strengths  be  plunged  into  it,  the  latter,  on  gradually  heating  the  bath,  become 
dyed.  The  process  is  necessarily  a  slow  one,  because  alizarine  is  only  slightly  soluble  in 
boiling  water,  and  as  the  mordants  can  only  combine  with  that  portion  actually  in  solution, 
a  constant  ebullition  of  the  liquid  must  be  kept  up,  in  order  to  cause  fresh  portions  of 
coloring  matter  to  dissolve  in  the  place  of  that  portion  taken  up  by  the  mordants.  A  very 
small  proportional  quantity  of  alizarine  is  required  in  order  to  dye  very  dark  colors,  but  it 
is  absolutely  necessary  that  the  bath  should  contain  no  trace  of  either  acid  or  base,  since 
the  former  would  combine  with  the  mordants,  and  the  latter  with  the  alizarine.  'When  the 
process  is  complete,  the  alumina  mordant  will  be  found  to  have  acquired  various  shades  of 
red,  while  the  iron  mordant  will  appear  either  black  or  of  difl'erent  shades  of  purple,  ac- 
cording to  the  strength  of  the  mordant  employed.  These  colors  are  as  brilliant  and  as  per- 
manent as  those  obtained  from  madder  by  means  of  a  long  and  complicated  process.  Never- 
theless, the  red  is  generally  found  to  have  more  of  a  purplish  hue,  and  the  black  to  be  less 
intense  than  when  madder  or  its  preparations  are  employed.  On  the  other  hand,  if  one  of 
the  finer  madder  colors  which  are  produced  on  calico,  such  as  pink  or  lilac,  be  examined, 
the  colors  are  found  to  contain,  in  combination  with  the  mordants,  almost  pure  alizarine. 
Hence  it  may  be  inferred,  that  alizarine  alone  is  required  for  the  production  of  these  colors, 
and  that  the  simple  combination  of  this  coloring  matter  with  the  mordants  is  the  principal 
end  which  is  to  be  attained  by  the  dyer  in  producing  them. 

Purpurine,  the  other  red  coloring  matter  of  madder,  with  which  the  matierc  colorante 
rose  of  Gaultier  de  Claubry  and  Persoz,  and  the  madder-purple  of  Runge,  are  substantially 
identical,  can  hardly  be  distinguished  by  its  appearance  from  alizarine,  which  it  also  resem- 
bles in  most  of  its  properties.  It  crystallizes  in  small  orange-colored  or  red  needles. 
"When  carefully  heated  it  is  almost  entirely  volatilized,  yielding  a  sublimate  of  shining 
orange-colored  scales  and  needles.  It  is  slightly  soluble  in  boiling  water,  giving  a  pink 
solution.  It  is  more  solulde  in  alcohol  than  in  water,  the  solution  having  a  deep  yellow 
color.  It  dissolves  in  concentrated  sulphuric  acid,  and  is  not  decomposed  on  heating  the 
solution,  even  to  the  boiling  point.  It  is  decomposed  by  boiling  nitric  acid,  and  yields,  like 
alizarine,  phthalic  acid.  It  is  distinguished  from  alizarine,  l)y  its  solulnlity  in  alum  liiiuor. 
When  treated  with  a  boiling  solution  of  alum  in  water,  it  dissolves  entirely,  yielding  a 
peculiar  opalescent  solution,  which  ajipears  of  a  Inight  ]jink  color  iiy  transmitted  light,  and 
yellowish  by  reflected  light.  The  solution  deposits  nothing  on  cooling,  but  on  adding  to  it 
an  excess  of  muriatic  acid  or  sulphuric  acid,  it  becomes  colorless,  and  the  purpurine  falls 
down  in  yellow  flocks.  On  this  property  depends  the  method  of  separating  it  from  alizarine. 
The  compounds  of  purpurine  with  l)ases  are  mostly  purple.  It  dissolves  in  alkalies  with  a 
bright  ()urplish-rcd  or  cherry-red  color.  If  the  solution  in  caustic  i)otash  or  soda  lie  exposed 
to  the  air,  its  color  changes  gradually  to  reddish-yellow,  and  the  jjurpurine  contained  in  it 
is  decomposed,  a  characteristic  which  also  serves  to  distinguish  purpurine  from  alizarine, 
the  alkaline  solutions  of  which  are  not  changed  by  the  action  of  oxygen.  The  composition 
of  purpurine  approaches  very  near  to  that  of  alizarine,  but  its  chemical  formula  is  un- 
known. It  comnumicates  to  calico,  which  has  been  printed  with  various  mordants,  colors 
similar  to  those  imparted  l)y  alizarine,  but  the  red  is  more  liery,  and  the  black  more  intense 
than  when  alizarine  is  employed.  On  the  other  hand,  the  purple  dyed  by  means  of  pur- 
purine has  a  disagreeable  reddish  tinge,  and  presents  an  unpleasant  contrast  with  the 
beautiful  purple  from  alizarine.  The  name  of  this  coloring  matter  is  therefore  very 
inappropriate,  and  is  calculated  to  mislead.     The  colors  dyed  with  purpurine  are  less  stable 


730  MADDER. 

than  those  dyed  with  alizarine,  they  are  less  able  to  resist  the  action  of  soap  and  other 
agents  than  the  latter.  Hence,  very  little  purpurine  is  found  in  combination  with  the  mor- 
(hmts,  in  such  madder  colors  as  have  undergone  a  course  of  treatment  with  alkalies  and 
at-iils,  after  having  been  dyed  ;  indeed,  the  principal  object  of  this  treatment  appears  to  be 
tlie  removal  of  this  and  other  substances,  so  as  to  leave  compounds  of  alizarine  only  on  the 
fabric.  Purpurine  seems  to  abound  more  in  the  lower,  stronger  qualities  of  madder  than 
in  the  finer.  To  tliis  cause,  Kobiquet  chiefly  ascribed  the  superioiity  of  the  latter  in  dye- 
ing fast  colors,  and  no  lietter  way  of  accounting  for  it  has  hitherto  been  suggested.  Pur- 
purine forms  the  lxi.~is  of  the  red  pigment  called  madder  lake. 

Ruhiacine  is  the  name  which  has  been  applied  to  a  yellow  crystallized  coloring  matter 
contained  in  madder.  It  coincides  in  most  of  its  properties  with  the  inadder-oraitge  of 
Ivungc.  It  crystallizes  in  greeni.sh-yellow  lustrous  scales  and  needles.  "When  heated  it  is 
entirely  volatilized,  yielding  a  crystalline  sublimate.  It  is  only  slightly  soluble  in  ))oiling 
water,  but  more  soluble  in  boiling  alcohol,  from  which  it  crystallizes  on  cooling.  It  dis- 
solves in  concentrated  sulphuric  acid,  and  is  not  decomposed  on  boiling  the  .solution.  It 
also  dissolves  in  Ijoiling  nitric  acid  without  being  decomposed.  It  dissolves  in  caustic  alka- 
lies with  a  purple  color.  Its  compounds  with  earths  and  metallic  oxides  are  mostly  red. 
When  treated  with  a  boiling  solution  of  pcrnitrate  or  perchloride  of  iron  it  dissolves 
entirely,  yielding  a  brownish-red  solution,  which  deposits  nothing  on  cooling,  but  gives,  on 
the  addition  of  an  excess  of  muriatic  acid,  a  yellow  flocculeut  precipitate,  consisting  of  a 
peculiar  acid,  culled  rubiacic  acid. 

Two  amorphous  resinous  coloring  matters,  forming  brownish-red  compounds  with  bases, 
have  also  been  obtained  from  madder.  Both  are  very  little  soluble  in  l)oiling  water.  One 
of  them  is  a  dark  brown,  brittle,  resin-like  substance,  vei'y  easily  soluble  in  alcohol,  which 
melts  at  a  temperature  a  little  above  212°  F.  The  other  is  a  reddish-brown  powder,  less 
soluble  in  alcohol  than  the  preceding.  These  two  coloring  matters,  together  with  rubiacine, 
constitute  probably  the  tamii/  or  dun  colorhir/  matter  of  the  older  chemists.  They  do  not 
contribute  to  the  intensity  of  the  colors  dyed  with  madder,  and  exert  a  very  prejudicial 
effect  on  the  beauty  of  the  dyes.  If  printed  calico  be  dyed  with  a  mixture  of  alizarine, 
and  any  one  of  these  three  coloring  matters,  the  colors  are  found  to  be  Ijoth  weaker 
and  less  beautiful  than  when  alizarine  is  employed  alone.  The  red  acquires  an  orange 
tinge,  and  the  purple  a  reddish  hue,  whilst  the  black  is  less  intense,  and  the  parts  of  the 
calico  which  should  remain  white  are  found  to  have  a  yellowish  color.  Hence  it  is  of  im- 
portance to  the  dyer  that  their  effect  should  be  counteracted  as  much  as  possible,  by 
preventing  them  cither  from  dissolving  in  the  dye-bath  or  from  attaching  themselves  to 
the  fabric. 

The  other  constituents  of  madder  possess  no  interest  in  themselves,  but  may  become 
of  importance  in  consequence  of  the  effects  which  they  produce  during  the  process  of  dye- 
ing. The  pectine,  in  the  state  in  which  it  exists  in  the  root,  is  probably  an  indifferent  sub- 
stiince,  but  in  consequence  of  the  ease  and  rapidity  with  which  it  passes  into  pectic  acid,  it  may 
in  dyeing  act  very  prejudicially  by  combining  wilh  the  mordants  and  preventing  them  taking 
up  coloring  matter.  The  extractive  matter  of  madder,  when  in  an  unaltered  state,  pro- 
duces no  injurious  effects  directly ;  but  by  the  action  of  oxygen,  csj)ecially  at  an  elevated 
temperature,  it  acquires  a  brown  color,  and  then  con  tributes,  together  with  the  rubiacine 
and  the  resinous  coloring  matters,  in  deteriorating  the  colors  and  sullying  the  white  parts 
of  the  fabric.  The  extractive  matter,  when  in  a  state  of  puritj',  has  the  appearance  of  a 
yellow  syrup,  like  honey,  wliich  is  easily  soluble  in  water  and  alcohol.  When  pure  it  is  not 
precipitated  from  its  watery  solution  by  any  earthy  or  metallic  salt,  but  if  the  solution  be 
evaporated  in  contact  with  the  air,  it  gradually  becomes  brown,  and  then  gives  an  abundant 
brown  precipitate  with  sugar  of  lead.  When  its  watery  solution  is  mixed  with  muriatic  or 
sulphuric  acid  and  boiled,  it  Ijccomes  green  and  deposits  a  dailv  green  powder.  Hence  this 
extractive  matter  has,  for  the  sake  of  distinction,  been  called  Chloroyeuine,  and  Rubichloric 
Arid.  The  bitter  principle  of  madder  will  be  referred  to  presently.  The  Xanthine  of 
Kuhlmann,  and  the  vmddcr-ijcllovt  of  Runge  arc  mixtures  of  the  extractive  matter  and  the 
bitter  princii)le.  The  sugar  contained  in  madder  is  probably  grape-sugar.  It  has  not 
hitherto  been  obtained  in  a  crystallized  state,  but  it  yields  by  fermentation  alcohol  and  car- 
l)onic  acid,  like  ordinary  sugar.  The  woody  fibre  which  is  left  after  madder  has  been 
treated  witli  various  solvents  until  nothing  moie  is  extracted,  always  letains  a  slight  reddish 
or  brownish  tinge  from  the  presence  of  some  coloring  matter  which  cannot  bfc  completely 
removed,  and  seems  to  adhere  to  it  in  the  same  way  as  it  does  to  the  cotton  fibre  of  im- 
mordanted  calico. 

There  is  a  question  connected  with  the  chemical  hi.story  of  m.adder  which  must  not  be 
passed  over  i-n  silence,  since  it  is  one  which  possesses  great  interest,  and  may  at  some  future 
time  V)eeome  of  great  importance,  viz.,  the  qtiestion  as  to  the  state  in  which  the  coloring 
matters  originally  exist  in  the  root.  It  has  long  been  known,  that  when  ground  madder  is 
kept  tightly  packed  in  casks  for  some  time,  it  constantly  improves  in  quality  for  several 
years,  after  which  it  again  deteriorates  ;    and  it  was  always  supposed  that  this  effect  was 


MADDER.  731 

due  to  some  process  of  slow  fermentation  going  on  in  the  interior  of  the  mass,  an  opinion 
which  seemed  to  be  justified  by  the  evident  increase  in  weiglit  and  vohime,  and  the  agglo- 
meration of  the  particles  which  took  place  at  the  same  time.  Nevertheless,  the  earlier 
chemical  examinations  of  madder  threw  no  light  whatever  on  this  part  of  the  subject,  since 
the  red  coloring  matters  were  found  to  be  very  stable  compounds,  not  easily  decomposed 
except  by  the  action  of  very  potent  agents,  so  that  when  once  formed  it  seemed  improbable 
that  they  would  be  at  all  affected  by  any  mere  process  of  fermentation.  Hence  some 
chemists  were  led  to  the  conclusion,  that  the  improvement  which  takes  place  in  the  quality 
of  madder  on  keeping,  is  caused  by  an  actual  formation  of  fresh  coloring  matter.  A  very 
simple  experiment  may  indeed  suffice  to  prove  that  the  whole  of  the  coloring  matter  does 
not  exist  ready  formed,  even  in  the  article  as  used  by  the  dyer.  If  ordinary  madder  be 
extracted  with  cold  water,  the  extract  after  being  filtered  has  generally  an  acid  reaction, 
and  cannot  contain  any  of  the  coloring  matters,  since  these  are  almost  insoluble  in  cold 
water,  especially  when  there  is  any  acid  present.  Nevertheless,  the  extract  when  gradually 
heated  is  found  capable  of  dyeing  in  the  same  way  as  madder  itself  If  the  extract  be 
made  tolerably  strong,  it  possesses  a  deep  yellow  color  and  a  very  bitter  taste  ;  but  if  it  be 
allowed  to  stand  in  a  warm  place  for  a  few  hours,  it  gelatinizes,  and  the  insoluble  jelly  which 
is  formed  is  found  to  possess  the  whole  of  the  tinctorial  power  of  the  liquid,  which  has  also 
lost  its  yellow  color  and  bitter  taste.  Hence,  it  may  be  inferred  that  the  substance  which 
imparts  to  the  extract  its  bitter  taste  and  yellow  color,  is  capable  also  of  giving  rise  to  the 
formation  of  a  certain  quantity  of  coloring  matter. 

In  1837  a  memoir  was  published  by  Decaisne,  containing  the  results  of  an  anatomical 
and  physiological  examination  of  the  madder  plant,  results  which  were  considered  so  im- 
portant that  a  prize  was  awarded  to  the  author  by  the  Royal  Academy  of  Sciences  of  Brus- 
sels. This  investigation  led  the  author  to  the  conclusion,  that  the  cells  of  the  living  plant 
contain  no  ready-formed  red  coloring  matter,  but  are  filled  with  a  transparent  yellow  juice, 
which,  on  exposure  to  the  atmosphere,  l)ecomes  reddish  and  opaque  in  consequence  of  the 
formation  of  red  coloring  matter.  Hence  he  inferred,  that  the  insoluble  red  coloring  matter 
was  simply  a  product  of  oxidation  of  the  soluble  yellow  one,  and  that,  consequently,  the 
more  complete  the  exposure  of  the  triturated  root  to  the  atmosphere,  the  greater  would  be 
its  tinctorial  power;  and  he  even  went  so  far  as  to  assert  that  all  the  proximate  principles 
olitained  from  the  root  were  derived  ultimately  from  one  single  substance  contained  in  the 
whole  plant.  That  the  fresh  roots,  before  being  dried,  do  indeed  contain  no  coloring  mat- 
ter capable  of  imparting  to  mordants  colors  of  the  usual  appearance  and  intensity,  may  be 
proved  by  the  following  experiment : — If  the  roots,  as  soon  as  they  are  taken  out  of  the 
ground,  are  cut  into  small  pieces  as  quickly  as  possible,  and  then  extracted  with  boiling 
spirits  of  wine,  a  yellow  extract  is  obtained  which,  after  being  filtered  and  evaporated, 
leaves  a  brownish-yellow  residue.  Now  this  residue  on  being  redissolvcd  in  water  is  found 
incapable  of  imparting  to  mordants  any  but  the  slightest  shades  of  color  ;  and,  on  the  other 
hand,  the  portion  of  the  root  left  after  extraction  with  spirits  of  wine,  on  being  subjected 
to  the  same  test  as  the  extract,  is  found  to  possess  as  little  tinctorial  power  as  the  latter. 
If,  however,  the  roots,  instead  of  being  treated  with  spirits  of  wine,  are  macerated  in  water, 
the  liquor,  on  l)eing  gradually  heated,  dyes  the  usual  colors  as  well  as  ordinary  madder. 
Hence  it  may  be  inferred  that  by  means  of  alcohol  the  color-producing  body  of  the  root 
may  be  separated  from  the  agent  which,  under  ordinary  circumstances,  is  destined  to  effect 
its  transformation  into  coloring  matter,  the  one  being  soluble  and  the  other  insoluble  in 
that  menstruum.  It  was  by  this  and  other  similar  facts  that  Schunck  was  led  to  an  exami- 
nation of  thi.s  part  of  the  subject.  He  infers  from  his  experiments  that  the  color-producing 
body  of  madder  is  identical  with  its  so-called  bitter  principle,  to  which  he  has  given  the 
name  of  Rnhian.  This  body,  wlien  pure,  has  the  following  i)roportics : — It  is  an  amorphous, 
.shining,  brittle  substance,  like  gum,  dark  l)rown  and  opa((ue  in  mass,  ))ut  yellow  and  trans- 
parent in  thin  layers.  Its  solutions  are  of  a  deep  yellow  color,  and  have  an  inten.sely  bittei- 
taste.  It  is  easily  soluble  in  water  and  alcohol.  The  watery  solution  turns  of  a  blood-red 
color,  on  the  addition  of  caustic  and  carbonated  alkalies,  and  gives  dark  red  i)rccipitate  with 
lime  and  baryta  water.  The  solution  gives  a  copious  light  red  precipitate  with  basic  acetate 
of  lead,  but  yields  no  precipitate  with  any  other  metallic  salt.  On  trying  to  dye  with  rubian 
in  the  usual  manner,  the  mordants  assume  only  the  faintest  shades  of  color.  If,  however, 
the  watery  solution  be  mixed  with  sulpluuic  or  muriatic  acid  and  boiled,  it  gradually  de- 
posits a  quantity  of  insoluble  yellow  flocks,  which  aft(>r  l)eiuf;  separated  l)y  filtration  ami 
well  washed,  arc  found  to  dye  tlie  same  colors  as  those  obtained  by  nii-ans  of  madder,  in 
fact,  these  flocks  contain  alizarine,  to  which  they  owe  their  tinctorial  i)()wer,  but  they  also 
contain  a  crj'stallized  yellow  coloring  matter,  similar  to,  but  not  identical  with  rubia'cine,  as 
well  as  two  resinous  coloring  matters,  which  Schunck  has  named  Veranlinc  and  liu/nirline, 
and  which  arc  probal^ly  identical  with  the  resinous  coloring  matters  before  referred  to  as 
being  obtained  from  ordinary  madder.  The  li<]uid  filtered  from  the  flocks  contains  an  un- 
crystallizable  sugar,  similar  to  that  which  is  obtained  from  madder  itself.  Rubian  is  not 
decomposed  by  ordinary  ferments,  such  as  yeast  and  decomposing  casein  ;  but  by  extract- 


732 


MADDER. 


in"  madder  with  cold  water,  and  adding  alcohol  to  the  extract,  a  substance  is  precipitated 
in  pale  red  flocks,  which  possesses  in  an  eminent  degi-ee  the  power  of  effecting  the  decom- 
position of  rubian.  It  a  watery  solution  of  the  latter  be  mixed  with  some  of  the  flocculent 
precipitate,  (after  having  been  collected  on  a  filter,  and  washed  with  alcohol,)  and  then  left 
to  stand  in  a  warm  place  for  some  hours,  the  mixture  is  converted  into  a  light  brown  jelly, 
which  is  so  thick  that  the  vessel  may  be  reversed  without  its  falling  out.  This  jelly,  when 
agitated  with  cold  water,  communicates  to  the  latter  very  little  color  or  taste,  proving  that 
the  rubian  has  undergone  com{)lete  decomposition  by  the  action  of  the  flocculent  substance 
or  ferment  added  to  its  solution.  The  cold  water,  however,  extracts  from  the  gelatinous 
mass  a  quantity  of  sugar,  Avhile  the  portion  left  undissolved  contains  alizarine,  verantinc, 
rubiretine,  and  a  crystalline  yellow  coloring  matter,  besides  a  portion  of  undecomposed  fer- 
ment. Rubian,  therefore,  by  the  action  of  strong  mineral  acids  and  of  the  peculiar  ferment 
of  madder,  is  decomposed,  yielding  sugar  and  a  variety  of  coloring  matters,  the  principal 
of  wiiich  is  alizarine.  It  appears,  therefore,  that  these  coloring  matters  are  not  originally 
contained  as  such  in  the  root,  but  are  formed  by  the  decomposition  of  one  parent  substance, 
which  alone  is  produced  by  the  vital  energies  of  the  plant.  In  addition  to  this  substance, 
the  plant  also  contains  another,  which  possesses  the  projicrty  of  rapidly  effecting  the  de- 
composition of  the  first.  The  two  are,  however,  during  the  living  state  of  the  plant,  pre- 
vented from  acting  on  one  another,  either  in  consequence  of  their  being  contained  in  diifer- 
ent  cells,  or  because  the  vital  energies  of  the  plant  resist  the  process  of  decomposition. 
During  the  drying  and  grinding  of  the  root,  the  decomposition  of  the  color-producing  body 
commences,  and  continues  slowly  during  the  period  that  the  powder  is  kept  before  being 
used.  It  is  finally  completed  during  the  process  of  dyeing  itself,  and  hence  no  trace  of 
color-producing  substance  can  be  detected,  either  in  the  liquor  or  the  residual  madder,  after 
the  operation  of  dyeing  is  concluded.  The  presence  of  oxygen  does  not  seem  to  be  essen- 
tial during  this  process  of  decomposition,  as  Decaisnc  supposed.  Nevertheless,  according 
to  Schunck,  rubian  does  in  reality  suffer  a  partial  oxidation,  when  its  watery  solution,  mixed 
with  some  alkali  or  alkaline  earth,  is  exposed  to  the  action  of  the  atmosphere,  giving  rise 
to  a  peculiar  acid,  called  by  him  rtthianic  acid.  When  rubian  is  heated  at  a  temperature 
considerably  exceeding  212"  F.,  it  is  converted  without  much  change  of  appearance  into  a 
substance  which  yields  by  decomposition  resinous  coloring  matters  in  the  place  of  alizarine. 
The  great  excess  of  these  coloring  matters  contained  in  the  madder  of  commerce  arises 
therefore  most  probably  from  the  high  temperature  employed  in  drying  the  root. 

Emploiiment  of  Madder  in  Di/ei/ir/. — After  the  account  which  has  just  been  given  of 
the  composition  of  madder,  it  may  easily  be  conceived  that  the  chemical  and  physical  phe- 
nomena which  occur  during  the  various  processes  of  madder  dyeing,  are  of  a  rather  com- 
plicated nature,  and  that  many  of  these  phenomena  have  not  yet  received  a  perfectly  satis- 
factory explanation.  Nevertheless,  the  present  state  of  our  knowledge  on  this  subject  may 
enable  us  to  give  a  consistent  explanation  of  the  facts  presented  to  us  by  the  experience  of 
the  dyer,  and  even  to  indicate  what  direction  our  labors  must  take  if  we  wish  to  improve 
this  branch  of  the  arts. 

In  order  to  produce  perfectly  f;ist  colors  in  madder  dyeing,  it  is  necessary  that  the  mad- 
der should  contain  a  large  proportion  of  carbonate  of  lime,  and  if  the  madder  is  naturally 
deficient  in  that  salt,  the  deficiency  may  be  supplied  either  by  using  calcareous  water  in 
dyeing,  or  by  adding  a  quantity  of  ground  chalk.  If  madder  be  treated  with  dilute  sul- 
phuric or  muriatic  acid,  so  as  to  dissolve  all  the  lime  contained  in  it,  and  then  washed  with 
cold  water  until  the  excess  of  acid  is  removed,  its  tinctorial  power  will  he  found  to  be  very 
much  diminished,  but  may  be  entirely  restored,  and  even  increased,  by  the  addition  of  a 
proper  quantity  of  lime-water  or  chalk.  Hence,  too,  Avignon  madder,  which  is  grown  in  a 
highly  calcareous  soil,  and  contains  so  much  carbonate  of  lime  as  to  effervesce  with  acids, 
affords  the  most  permanent  colors ;  whilst  Alsace  madder  requires  the  addition  of  car- 
bonate of  lime  in  order  to  produce  the  same  effect.  This  fact  was  first  pointed  out  by 
riausmann,  who,  after  having  produced  very  fine  reds  at  Rouen,  encountered  the  greatest 
obstacles  in  dyeing  the  same  reds  at  Logelbaeh,  near  Colniar,  wliere  he  went  to  live.  Nu- 
merous trials,"  undertaken  with  the  view  of  obtaining  the  same  success  in  his  new  establish- 
ment, proved  that  the  cause  of  his  favorable  results  at  Rouen  existed  in  the  water,  which 
contained  carbonate  of  liuie  in  solution,  whilst  the  water  of  Logelbaeh  was  nearly  pure. 
lie  then  tried  a  factitious  calcareous  water,  by  adding  chalk  to  his  dye-bath.  Having  ob- 
tained the  most  satisfactory  results,  he  was  not  long  in  producing  here  as  beautiful  and  as 
solid  reds  as  he  had  done  at  Rouen.  This  simple  fact  led  to  the  production  of  a  series  of 
lengthy  memoirs  on  the  part  of  some  of  the  French  chemists  and  calico-printers;  which 
fully  confirmed  the  results  of  Hausmann,  without,  however,  leading  to  a  satisfactory  expla- 
nation of  them.  The  experiments  of  Robiquet  prove  that  in  dyeing  with  pure  alizarine  the 
least  addition  of  lime  is  rather  injurious  than  otherwise,  as  it  merely  weakens  the  colors 
without  adding  to  their  durability.  Hence,  the  beneficial  effect  of  lime  can  only  be  ac- 
counted for  by  some  action  which  it  exerts  on  other  constituents  of  the  root.  Bartholdi 
imagined  that  this  action  consisted  simply  in  the  decomposition  of  the  sulphate  of  magne- 


I 


MADDER.  733 

sia,  which  he  found  to  be  contained  in  ordinary  madder.  It  was  asserted  by  others,  that 
the  carbonate  of  lime  served  to  neutralize  some  free  acid,  supposed  by  Kuhlmann  to  be 
malic  acid,  which  was  present  in  some  madders,  and  which  not  only  to  a  great  degree  pre- 
vented the  coloring  matters  from  dissolving  in  the  dye-bath,  but  also  combined  with  the 
mordants  to  the  exclusion  of  the  latter.  Though  later  researches  have  failed  to  detect  the 
existence  of  malic  acid  in  madder,  still  it  is  certain  that  all  watery  extracts  of  madder  con- 
tain pectic  acid,  which  probably  exists  in  the  root  originally  as  pectine  ;  and  that  this  acid, 
when  in  a  free  state,  acts  most  injuriously  in  dyeing  with  alizarine,  but  ceases  to  do  so  as 
soon  as  it  is  combined  with  lime.  Nevertheless,  it  seems  that  madder  which  is  naturally 
deficient  in  lime,  cannot  be  made  to  replace  entirely  such  madder  as  has  been  grown  in  a 
calcareous  soil,  however  great  an  excess  of  chalk  be  used  in  dyeing.  Hence  Robiquet  was 
led  to  the  conclusion,  that  the  inferior  kinds  of  madder,  which  are  also  the  most  deficient 
in  lime,  contain  more  purpurine  and  less  alizarine  than  the  superior  kinds,  and  that  the  car- 
bonate of  lime  serves  partly  to  combine  with  the  purpurine  and  prevent  it  from  uniting  with 
the  mordants,  and  thus  producing  less  permanent  dyes.  The  experiments  of  Schunck  have 
proved  that  not  only  pectic  acid,  but  also  rubiacine  and  the  resinous  coloring  matters  of 
madder,  act  detrimentally  in  dyeing  with  pure  alizarine,  by  deteriorating  the  colors  and 
sullying  the  white  parts  of  the  fabric,  and  that  these  "effects  are  entirely  neutralized  by  the 
addition  of  a  little  lime-water  to  the  dye-bath.  If  in  dyeing  with  madder  the  whole  of  the 
coloring  matters  were  in  a  free  state,  the  resinous  and  yellow  coloring  matters  would,  ac- 
cording to  Schunck,  unite  with  the  mordants,  to  the  exclusion  of  the  alizarine,  yielding 
colors  of  little  permanency  and  of  a  disagreeable  hue ;  but  on  adding  lime  tliey  combine 
with  it,  and  the  alizarine,  being  less  electro-negative,  then  attaches  itself  to  the  mordants  or 
weaker  bases.  A  great  excess  of  lime  would  of  course  have  an  injurious  effect  by  combin- 
ing also  with  the  alizarine,  and  preventing  it  from  exerting  its  tinctorial  power.  In  prac- 
tice, a  little  less  lime  is  added  than  is  sufficient  to  take  up  the  whole  of  the  impurities  with 
which  the  alizarine  is  associated,  thus  allowing  a  portion  of  the  former  to  go  to  the  mor- 
dants, to  be  subsequently  removed  by  treatment  with  soap  and  other  detergents.  Lastly,  it 
has  been  asserted  by  Kochlin  and  Persoz,  that  when  lime  is  used  in  dyeing  with  madder, 
the  colors  produced  are  not  simply  compounds  of  coloring  matter  with  mordants,  but  con- 
tain also  in  chemical  combination  a  certain  quantity  of  lime,  which  adds  very  much  to  their 
stability.  It  is  probable  that  all  these  causes  contribute  in  producing  the  effect.  The  car- 
bonates of  magnesia  and  zinc,  acetate  and  neutral  pliosphate  of  lime,  and  the  protoxides  of 
leal,  zinc  and  manganese,  act  in  a  similar  manner  to  carbonate  of  lime  in  madder  dyeing, 
but  are  less  efficient. 

Damboarney  and  Beckman  have  asserted,  that  it  is  more  advantageous  to  employ  the 
fresh  root  of  midder  than  that  which  has  been  submitted  to  desiccation,  especially  by  means 
of  stoves.  But  in  its  state  of  freshness,  its  volume  becomes  troublesome  in  the  dj'e-batli, 
and  uniform  observation  seems  to  prove  that  it  ameliorates  by  age  up  to  a  certain  point. 
Besides,  it  must  be  rendered  susceptible  of  keeping  and  carrying  easily. 

In  dyeing  printed  calicoes  with  madder,  the  general  course  of  proceeding  is  as  follows  : — 
The  midder  having  been  mixed  in  the  dye-vessel  with  the  proper  quantity  of  water,  and, 
if  necesj-ary,  with  chalk,  the  liquid  is  heated  slowly  by  means  of  fire  or  steam,  and  the 
fabric  is  introduced  and  kept  constantly  moving,  until  the  dyeing  is  finished.  The  tempera- 
ture should  be  kept  low  at  first,  and  should  be  gradHally  raised,  without  allowing  it  to  fall, 
until  it  reaches  the  boiling-point ;  and  the  boiling  may,  if  necessary,  be  continued  for  a 
short  time.  The  chief  object  of  the  gradual  heating  seems  to  be  to  allow  the  ferment  to 
exert  its  full  power  on  the  rubian  or  color-producing  body,  for  this  process,  like  all  pro- 
cesses of  fermentation,  is  most  active  at  a  temperature  of  about  100^  F.,  and  is  arrested  at 
212'  F.  In  dyeing  quickly,  less  permanent  colors  are  also  produced,  in  consequence,  prob- 
ably, of  the  coloring  matters  combining  with  the  more  superficial  portions  of  the  mordants, 
and  not  penetrating  sufficiently  into  the  interior  of  the  vegetable  fibre.  The  fiistest  colors 
are  produced  by  dyeing  at  a  moderate  temperature,  and  not  allowing  the  liquid  to  boil. 
By  boiling,  the  madder  becomes  more  thoroughly  exhausted,  and  a  greater  depth  of  color 
is  attained,  but  the  latter  resists  less  perfectly  the  action  of  soap  and  other  agents,  than  the 
same  shade  dyed  at  a  lower  temperature.  The  time  occupied  in  dyeing  varies  according  to 
the  nature  and  intensity  of  the  colors  to  be  produced ;  but  there  is  little  advantage  in 
allowing  it  in  any  case  to  exceed  three  hours,  since  the  gain  in  color  acquired  is  more  tlian 
counterbalanced  by  the  loss  of  time  and  increased  expenditure  of  fuel  caused  by  a  long- 
continued  ebullition.  In  dyeing  ordinary  madder  coloi-s,  such  as  red,  black,  chocolate,  and 
common  purple,  which  do  not  require  much  treatment  after  dyeing,  in  order  to  give  them 
the  desired  tone  and  intensity,  strong  but  inferior  qualities  of  madder  may  be  used  with 
advantage ;  and  various  other  dye-stuffs,  such  as  peachwood,  quercitron  bark,  sumac,  &c., 
are  often  added  to  the  madder,  in  order  to  vary  the  shade  and  depth  of  color.  But  for  the 
finer  colors,  such  as  pink  and  fine  purple,  whicli  after  dyeing  must  be  subjected  to  a  long 
course  of  treatment  with  soap  and  aciils  btfore  they  assume  the  requisite  beauty  and  deli- 
cacy of  hue,  it  is  necessary  to  employ  the  finest  qualities  of  madder  ;  for  if  dyed  with  infe- 


734 


MADDER. 


rior  qualities  they  would  resist  only  imperfectly  the  requisite  after-treatment,  and  great  care 
must  be  observed  in  regulating  the  temperature  during  dyeing.  The  addition  of  other  dve- 
stuffs,  in  their  case,  would  be  not  only  useless,  but  positively  injurious.  The  use  of  dift'er- 
ent  kinds  and  <iualities  of  madder  in  conjunction,  is  often  found  to  be  attended  with  benefit, 
arising  probably  from  the  circumstance  of  one  kind  supplying  some  material  or  other,  such 
as  ferment  or  carbonate  of  lime,  in  which  the  other  is  deficient. 

The  chemical  processes  which  take  place  during  the  operation  of  dyeing  may  be  shortly 
described  as  follows  : — In  the  first  place,  the  water  of  the  dye-bath  extracts  the  more  sol- 
uble constituents  of  the  madder,  such  as  the  sugar,  extractive  matter,  and  bitter  principle. 
Tlie  latter  substance  is  decomposed  by  the  ferment,  and  the  coloring  matter  thereby  formed 
is  added  to  that  which  already  exists  in  the  root.  As  the  temperature  rises,  the  less  soluble 
constituents,  such  as  the  alizarine,  purpurine,  rubiacine,  the  resinous  coloring  matters,  the 
pectine  and  pectic  acid,  begin  to  dissolve,  and  as  they  dissolve  they  combine  partly  with 
the  mordants  of  the  fabric,  partly  with  the  lime  and  other  bases  contained  in  the  root  or 
added  to  the  dye-bath,  and  thus  permit  the  liquid  to  take  up  fresh  quantities  from  the  mad- 
der. If  the  quantity  of  madder  was  exactly  proportioned  to  the  quantity  of  fabric  to  be 
dyed,  then  it  becomes,  in  this  way,  gradually  exhausted  of  all  available  coloring  matter. 
The  extractive  matter  at  the  same  time  acquires  a  brown  color  by  the  combined  action  of 
the  heat  and  oxygen,  and  covers  the  whole  surface  of  the  fabric  with  a  uniform  brown 
tinge.  When  the  dyeing  is  concluded,  the  liquor  appears  muddy  and  of  a  pale  dirty  red 
color.  It  still  contains  a  quantity  of  coloring  matter  in  a  state  of  combination  with  lime 
and  other  bases  from  the  madder,  or  with  portions  of  the  mordant  mechanically  detached 
from  the  fabric.  The  residual  madder  at  the  bottom  of  the  liciuor  also  contains  a  quantity 
of  coloring  matter  in  a  similar  state  of  combination.  By  mixing  the  residue  and  the  liquor 
with  sulphuric  or  muriatic  acid,  boiling,  and  then  washing  with  water,  the  various  bases  are 
removed,  and  the  coloring  matter  is  thus  made  available  for  dyeing.  Occasionally,  when  a 
very  great  depth  of  color  is  required,  it  is  found  advisable  to  let  the  goods  pass  through  a 
second  dyeing  operation,  instead  of  obtaining  the  requisite  shade  at  once. 

After  the  calico  has  been  removed  from  the  dye-bath  and  washed  in  water,  it  presents  a 
very  unsightly  appearance.  The  alumina  mordant  has  acquired  a  dirty  brownish-red  color, 
and  the  iron  mordant  a  black  or  brownish  purple,  according  to  its  strength,  whilst  the  white 
portions  are  reddish-brown.  In  the  case  of  ordinary  colors,  the  fabric  is  now  passed  through 
a  mixture  of  boiling  bran  and  water,  or  through  a  weak  solution  of  chloride  of  lime,  or  it 
is  exposed  for  some  time  on  the  grass  to  the  action  of  air  and  light,  or  it  is  subjected  to 
several  of  these  processes  in  succession,  by  which  means  the  impurities  adhering  to  tlic 
mordants  or  the  fibre  are,  in  a  great  measure,  either  removed  or  destroyed,  the  white  por- 
tions recovering  their  purity,  and  the  red,  black,  purjile,  and  chocolate,  appearing  after- 
wards sufficiently  bright  for  ordinary  purposes.  That  the  colors,  however,  even  after  being 
thus  treated,  still  contain  in  combination  with  the  mordants  other  substances  in  addition  to 
the  red  coloring  matters,  may  be  proved  by  a  very  simple  experiment.  If  a  few  yards  of 
some  calico,  which  has  been  treated  as  just  described,  be  immersed  in  dilute  muriatic  acid 
in  the  cold,  the  mordants  are  removed,  and  the  colors  aie  destroyed  ;  orange-colored  stains 
being  left  on  the  places  where  they  were  before  fixed.  After  washing  the  calico  with  cold 
water,  the  orange-colored  matter  may  be  dissolved  in  alkali,  and  the  calico  left  entirely 
white.  The  solution,  which  is  browniah-red,  gives,  with  an  excess  of  acid,  a  reddish-brown 
flocculent  precipitate.  This  precipitate,  after  being  collected  on  a  filter  and  well  washed 
•with  water,  is  found  to  be  only  ])artially  soluble  in  boiling  alcohol,  a  brown  substance,  con- 
sisting partly  of  pectic  acid,  being  left  undissolved.  Tiie  yellow  alcoholic  solution  leaves, 
on  spontaneous  evaporation,  a  brown  crystalline  residue,  which  is  found  on  examination  to 
contain  alizarine,  purpurine,  a  little  rubiacine,  or  some  similar  compound,  and  a  brown 
amorphous  substance.  The  removal  of  these  various  impurities,  associated  with  the  aliza- 
rine, seems  to  l)e  the  principal  object  of  the  treatment  to  whicb  madder  colors  are  subjected, 
when  it  is  desired  to  give  them  the  highest  degree  of  brilliancy  of  which  they  are  suscep- 
tible. This  course  of  treatment,  as  applied  to  printed  calicoes,  may  be  shortly  described  as 
follows  : — The  goods,  after  being  very  fully  dyed,  generally  with  the  addition  of  chalk,  and 
then  washed,  are  passed  for  some  time  through  a  solution  of  soap,  which  is  heated  to  a 
moderate  temperature.  By  this  means  a  great  deal  of  color  is  removed,  as  may  be  seen  by 
the  red  tinge  of  the  soap-liquor,  and  the  purity  of  the  white  portions  is  almost  entirely 
restored.  During  this  process  the  brown  and  yellow  coloring  matters  are  probably  removed 
by  double  decomposition,  the  alkali  of  the  soap  combining  with  and  dissolving  them,  while 
the  fat  acid  takes  their  place  on  the  fabric.  After  being  washed,  the  goods  are  passed 
through  a  weak  solution  of  acid,  mostly  sulphuric  or  oxalic  acid,  or  an  acid  tin  salt,  which 
causes  the  colors  to  assume  an  orange  tinge.  The  point  at  which  the  action  of  this  acid 
liquid  is  to  be  arrested  can  only  be  ascertained  by  practice.  The  next  step  in  the  process 
is,  after  washing  the  goods,  to  treat  them  again  with  soap  liquor,  which  is  gradually  raised 
to  the  boiling  point,  and  they  are  lastly  subjected  to  the  action  of  soap  liquor  in  a  close 
vessel  under  jiressure.      By  exposing  the  goods  on  the  grass  for  some  time  after  the  first 


1 


MADDER. 


735 


soai)ing,  the  use  of  acid  may  be  obviated,  but  the  process  then  becomes  much  more  tedious. 
Ill  this  way  are  produced  those  beautiful  pinks  and  lihies,  which,  for  delicacy  of  hue,  com- 
bined with  great  permanence,  are  not  surpassed  by  any  dyed  colors  known  in  the  arts. 
Whether  the  fat  acid  of  the  soap  employed  forms  an  essential  constituent  of  these  colors  is 
not  certainly  known,  but  it  is  probable  that  it  contributes  to  their  beauty  and  durability.  It 
is  certain,  however,  that  they  alwavs  contain  fat  acid.  If  a  piece  of  calico  which  has  gone 
through  the  processes  just  described  be  ti-eated  with  muriatic  acid,  the  color  is  destroyed, 
and  a  yellow  stain  is  left  in  its  place.  This  yellow  st;iin  disappears  on  treating  the  calico, 
after  washing  with  water,  with  alkali,  yielding  a  solution  of  a  beautiful  purple  color.  Tliis 
solution  gives  again  with  an  excess  of  acid  a  yellow  flocculent  precipitate,  which,  after  fihra- 
tion,  dissolves  almost  entirely  in  boiling  alcohol,  and  the  solution  on  evaporation  aflbrds 
needle-shaped  cr\'sta!s  of  pure  alizarine,  mixed  with  white  masses  of  fat  acid.  The  latter, 
therefore,  seems  to  occupy  the  place  taken  up  by  the  impurities  before  the  treatment  with 
soap.  Tills  experiment  serves  also  to  prove  that  it  is  alizarine  which  forms  the  basis  of  the 
more  permanent  colors  afforded  by  madder,  though,  on  the  other  hand,  as  in  dyeing  the 
finer  madder  colors,  it  cannot  be  denied  that  the  coloring  matters  which  are  removed  by  the 
treatment  with  soap  and  acids  contribute  to  the  effect  produced  in  dyeing  ordinary  madder 
colors. 

The  same  result  is  attained  in  dyeing  Turkey  red,  but  the  process  employed  is  somewhat 
different,  and  much  more  complicated. 

The  attempts  which  have  been  made  at  various  times  to  obtain  an  extract  of  madder, 
capable  of  being  applied  in  making  so-called  steam  colors  for  calico  and  other  fabrics,  have 
not  been  completely  successful.  A  very  beautiful  pink  has  been  produced  by  Gastard  and 
Girardin,  in  France,  by  printing  on  calico,  previously  prepared  with  some  mordant,  an  am- 
moniiical  solution  of  an  extract  of  madder,  called  colorlne,  but  it  is  not  much  superior, 
eitiier  as  regards  its  hue  or  its  degree  of  permanency,  to  what  can  be  obtained  by  easier 
processes  from  dyewoods  and  other  materials. 

Madder  is  not  so  much  employed  in  woollen  dyeing,  especially  in  this  country,  as  in  cot- 
ton dyeing  and  printing.  Oily  ordinary  woollen  goods  are  dyed  red  with  madder,  since  the 
color  is  not  so  brigiit  as  that  obtained  from  cochineal  or  lac,  though  it  is  more  permanent 
ami  cheaper.  A  mixture  of  alum  and  tartar  is  employed  as  a  mordant.  The  addition  of  a 
little  muriate  of  tin  in  dyeing,  imparts  to  the  color  a  more  scarlet  tinge.  The  bath  of  mad- 
der, at  tiie  rate  of  from  8  to  16  ounces  to  the  pound  of  cloth,  is  heated  to  such  a  degree  as 
to  be  just  bearable  by  the  hand,  and  the  goods  are  then  dyed  by  the  wince,  without  heating 
the  bath  more  until  the  coloring  matter  is  fixed.  Yitalis  prescribes  a5  a  mordant,  one-fourth 
of  alum  and  one-sixteenth  of  tartar;  and  for  dyeing,  one-third  of  madder,  with  the  addi- 
tion of  a  twenty-fourth  of  solution  of  tin,  diluted  witli  its  weiglit  of  water,  lie  raises  the 
temperature  in  the  space  of  one  hour  to  200  \  and  afterwards  he  boils  tor  3  or  4  minutes — 
a  circumstance  which  is  believed  to  contribute  to  the  fixation  of  the  color  The  batii,  after 
dyeini,  appears  to  contain  much  yellow  coloring  matter.  Sometimes  a  little  archil  is  added 
to  the  madder,  in  order  to  give  the  dye  a  pink  tinge  ;  but  the  effect  is  not  lasting.  By  pa.<s- 
ing  the  goods  after  dyeing  through  weak  alkali,  the  color  acquires  a  bluish  tinge.  By  add- 
ing other  dye  stuffs,  such  as  fustic,  peach  wood  and  logwood,  to  the  madder  in  dyeing,  vari- 
ous shades  of  brown,  drab,  &c.,  are  obtained.  Madder  is  also  used  in  conjunction  with 
woad  and  indigo  in  dyeing  woollen  goods  blue,  in  order  to  impart  to  the  color  a  reddish 
tinge. 

Silk  is  seldom  dyed  with  madder,  because  cochineal  affords  brighter  tints. 

Preparations  of  Madder. — The  numerous  analytical  investigations  of  niaddor,  under- 
taken chiefly  in  consequence  of  the  Societe  Industrielle  de  Mulhouse  having  offered  in  the 
year  1826  a  premium  for  a  means  of  discovering  tli<>  real  quantity  of  coloring  matter  in  the 
root,  and  of  determining  the  comparative  value  of  different  samples  of  madder,  led  to 
many  attempts  on  the  part  of  chemists  to  improve  the  quality  of  this  dye-stuff"  by  means 
of  chemical  agents,  and  thus  render  it  more  fit  for  the  purjioses  to  wliich  it  is  applied. 
Kobiijuet  and  I'ersoz  were  the  first  to  point  out  the  advantages  which  result  from  submit- 
ting madder,  previous  to  its  being  used,  to  the  action  of  strong  acids.  They  showed  that, 
by  acting  on  madder  with  strong  sulphuric  acid,  and  then  carefully  washing  out  the  acid 
with  Water,  a  product  was  obtained,  wiiich  not  only  possessed  a  greater  tinctorial  power  than 
the  original  material,  but  also  dyed  much  brighter  colors.  This  iniiiortant  discovery,  which 
was  not,  like  so  many  others,  arrived  at  by  chance,  but  was  purely  the  result  of  scientific 
investigation,  did  not  at  first  receive,  on  the  part  of  practical  men,  the  appreciation  which 
it  deserved.  The  product  obtained  by  the  action  of  sul[)liuric  acid  on  madiler,  wliich  in  the 
first  instance  was  called  rhnrhon  sa/furiqur^  afterwards  r/<rr<iiichie,  was -first  manufactured 
on  a  large  scale  by  MM.  Lagier  and  Thomas  of  Avignon,  but  so  girat  were  the  pn-judicts 
entertained  by  dyers  and  calico-printers  against  its  use  at  the  commencement,  that  years 
elapsed  before  tliey  could  lie  overcome  ;  indeed,  they  were  partly  justified  by  the  imperfect 
nature  of  the  product  itself  The  persevering  efforts  to  improve  the  method  of  manufac- 
ture, and  adapt  it  to  the  wants  of  the  consumer,  were  at  last  attended  with  succes.s,  so  that 


736 


MADDER. 


at  the  present  day  garancine  has  come  to  be  used  to  as  great  an  extent  as  madder,  and  huge 
quantities  are  now  manufactured  in  France  and  other  countries. 

It  was  supposed  by  Robiquet,  that  by  the  action  of  sulphuric  acid  on  madder,  the  sac- 
charine, mucilaginous,  and  extractive  matters  of  the  root  were  destroyed,  and  thus  hindered 
from  producing  any  injurious  effects  in  dyeing,  and  that  the  woody  fibre  was  at  the  same 
time  charred,  so  as  to  prevent  it  from  attracting  and  binding  any  of  the  coloring  matter. 
This  explanation  is  not  entirely  correct,  since  it  is  not  necessary  to  carry  the  action  so  far 
as  actually  to  carbonize  any  of  the  constituents  of  the  root,  and  it  is  also  doubtful  whether 
the  woody  fibre  ever  attracts  the  useful  coloring  matters  in  any  considerable  degree.  The 
accoinit  above  given  of  the  chemical  constitution  of  madder,  may  easily  lead  us  to  the  con- 
clusion, that  during  the  action  of  the  acid,  the  following  processes  take  place : — 1.  The 
bitter  principle  or  color-producing  body  of  the  root  is  decomposed,  yielding,  among  other 
products,  a  quantity  of  alizarine  which  did  not  previously  exist.  2.  The  red  coloring  mat- 
ters are  rendered  by  the  acid  insoluble  in  water,  and  thus  it  becomes  possible  to  wash  out 
the  extractive  matter,  sugar,  &c.,  without  the  madder  losing  any  of  its  tinctorial  power. 
3.  The  lime,  magnesia,  and  other  bases  which  are  combined  in  the  root  with  coloring  mat- 
ter, or  would  combine  with  it  during  the  dyeing  process,  are  removed  by  the  acid,  and  thus 
prevented  from  exerting  any  injurious  action.  The  subsequent  addition  of  a  suitable  quan- 
tity of  lime,  soda,  or  other  base,  serves  to  neutralize  the  effect  of  the  excessive  amount  of 
pectic  acid  and  resinous  coloring  matters,  which  were  set  free  by  the  action  of  the  mineral 
acid. 

The  method  of  manufacturing  garancine,  as  practised  at  the  present  day,  may  be  shortly 
described  as  follows  :  —The  ground  madder  is  mixed  with  water,  and  the  mixture  is  left  to 
stand  for  some  hours.  During  this  time  it  is  probable  that  the  rubian  is  decomposed  by  the 
ferment  of  the  root,  otherwise  a  great  loss  would  be  experienced.  More  water  is  now  added, 
in  order  to  remove  all  the  soluble  matters,  and  is  then  run  off.  The  liquid  contains  sugar, 
and  is  employed  on  the  continent  for  the  preparation  of  a  kind  of  spirit,  which,  on  account 
of  its  peculiar  smell  and  flavor,  cannot  be  consumed  as  a  beverage,  but  is  used  in  the  arts 
for  the  preparation  of  varnishes  and  other  purposes.  A  sufficient  quantity  of  alcoholic  spirit 
is  thus  obtained  to  pay  for  the  whole  cost  of  the  process.  The  residue  left  after  washing 
the  madder  may  be  employed  for  dyeing  without  any  further  preparation,  and  is  then  called 
flcur  dc  garance.  In  order  to  convert  it  into  garancine,  it  is  mixed  with  sulphuric  acid, 
and  the  mixture  is  heated  and  left  to  itself  for  some  time.  Water  is  then  added  in  succes- 
sive portions  until  the  excess  of  acid  is  removed.  The  pectic  acid  of  the  root  always  retains 
a  portion  of  the  sulphuric  acid  in  chemical  combination  ;  and  the  compound  being  but  little 
soluble  in  water  would  require  for  its  removal  a  very  long  washing.  The  addition  of  a 
small  quantity  of  carbonate  of  soda,  by  neutralizing  this  double  acid,  serves  to  abridge  the 
time  of  washing  very  considerably.  The  residue  is  then  filtered  on  strainers,  pressed,  dried, 
and  lastly  ground  into  a  fine  powder.  The  powder  has  a  dark  reddish-brown  color,  and  a 
peculiar  "odor,  different  from  that  of  madder,  but  no  taste.  It  connnunicatos  hardly  any 
color  to  cold  water.  Dyeing  with  garancine  is  attended  with  the  following  advantages : — 
1.  The  whole  tinctorial  power  of  the  madder  is  exerted  at  once,  and  garancine  is  therefore 
capable  of  dyeing  more  than  the  material  from  which  it  is  made.  2.  The  colors  produced 
Ijy  its  means  are  much  brighter  than  those  dyed  with  madder,  and  the  parts  of  the  fabric 
destined  to  remain  white  attract  hardly  any  color,  so  that  very  little  treatment  is  required 
after  dyeing.  3.  Much  less  attention  is  re(iuired  in  regard  to  the  temperature  of  the  dye- 
bath,  and  its  gradual  elevation,  than  with  madder,  and  a  continued  ebullition  produces  no 
injurious  effects,  but  only  serves  to  exhaust  the  material  of  all  its  coloring  matter.  On  the 
other  hand,  garancine  colors  are  not  so  fast  as  madder  colors  ;  they  do  not  resist  so  well  the 
action  of  soap  and  acids,  and  hence  garancine  cannot  be  employed  for  the  production  of 
the  more  permanent  colors,  such  as  pink  and  fine  purple.  By  the  use  of  a  product  which 
was  patented  by  Pincoffs  and  Hchunck  several  years  ago,  and  which  is  obtained  by  exposing 
garancine  to  the  action  of  steam  of  high  pressure,  it  is  indeed  possible  to  dye  as  beautiful 
and  as  permanent  a  purple  as  with  madder,  and  its  use  is  attended  f)y  a  considerable  saving 
of  time  as  well  as  of  dyeing  material  and  soap,  but  it  is  not  so  well  adapted  for  dyeing 
pink.  As  yet,  therefore,  we  have  not  sueceedecl  in  obtaining  a  pro])aration  which  shall  serve 
as  a  perfect  substitute  for  madder,  and  the  latter  consequently  continues  to  be  emiiloyed  for 
some  purposes. 

The  residue  left  after  dyeing  with  madder,  as  well  as  the  dyeing  liquor,  still  contain  some 
coloring  matter,  in  a  state  of  combination,  as  mentioned  above.  By  acting  on  it  with  sul- 
phuric acid,  it  affords  a  product  similar  to  garancine,  which  is  called  (jaranceux.  This 
product  is,  however,  adapted  only  for  dyeing  red  and  black,  as  it  docs  not  afford  a  good 
purple.  Numerous  other  methods  of  treating  madder  for  the  use  of  tiie  dyer  have  been 
invented  and  patented  of  late  years,  but  they  are  not  sufficiently  important  to  merit  descrip- 
tion within  the  li)nits  of  the  present  article. 

MAHOGANY.  The  wood  of  a  tree  {Smetenia  mahogoni)  which  is  a  native  of  the 
West  Indies.     This  wood  appears  to  have  been  first  brought  to  England  in  1724. 


MAHOGANY.  737 

Spanish  mahogany  is  imported  from  Cuba,  St.  Domingo,  the  Spanish  Main,  and  several 
of  the  West  India  Islands,  in  logs  about  26  inches  square  and  10  feet  long.  Its  general 
character  is  well  known,  from  its  extensive  use  in  cabinet  work. 

HoN'DCRAS  mahogany  is  generally  lighter  than  the  Spanish,  and  more  open  and  irregular 
in  its  grain.  This  is  imported  in  large  logs,  many  of  4  feet  square  and  18  feet  in  length. 
Planks  are  sometimes  obtained  of  7  feet  in  width.  According  to  Mr.  Chief-Justice  Temple, 
"  the  cutting  commences  in  the  month  of  August.  In  April  or  May,  in  which  months  the 
ground  has  become  perfectly  hard  from  the  continued  dry  weather,  the  wood  is  carried 
upon  trucks  drawn  by  bullocks  to  the  water  side,  and  about  the  middle  of  June,  when  the 
rivers  are  swollen  by  the  floods,  the  logs  are  floated  down  about  10  miles  from  the  mouths 
of  tlie  different  rivers,  where  they  are  confined  by  a  heavy  boom  drawn  across  the  stream. 
Here  the  owners  select  their  respective  logs  from  them  into  rafts,  and  so  float  them  down 
to  the  sea.  The  mahogany  is  always  trucked  in  the  middle  of  the  night,  the  cattle  not 
being  able  to  perform  such  labovious  work  during  the  heat  of  the  day.  It  is  a  picturesque 
and  striking  scene,  this  midnight  trucking.  The  lowing  of  the  oxen,  the  creaking  of  the 
wheels,  the  shrill  cries  of  the  men,  the  resounding  cracks  of  their  whips,  and  the  red  glare 
of  the  pine  torches,  in  the  midst  of  the  dense  dark  forest,  produce  an  elFect  approaching  to 
sublimity. 

"  An  impression  has  latterly  existed  that  almost  all  the  mahogany  in  British  Honduras 
has  been  cut.  This,  however,  is  a  mistake.  There  is  sufficient  wood  in  the  country,  both 
on  granted  and  ungranted  land,  to  supply  the  European  as  well  as  the  American  markets 
for  many  years  to  come.  A  considerable  quantity  of  mahogany  has  been,  within  the  last 
few  years,  cut  in  the  state  of  Honduras  and  on  the  Mosquito  shore ;  but  the  mahogany 
works  in  the  former  country  have  been  almost  entirely  abandoned,  partly  on  account  of  the 
wood  which  is  accessible,  being  nearly  all  cut,  and  partly  on  account  of  the  extra  freight 
and  insurance  which  are  required  when  vessels  are  loaded  on  that  coast.  From  the  Mos- 
quito shore  very  few  cargoes  have  been  lately  sent,  for  the  wood  which  grows  there,  al- 
though it  is  very  large,  is  of  inferior  quality.  The  mahogany  tree  requires  a  rich  dry  soil. 
The  best  mahogany  is  found  to  the  north  of  the  river  Belize.  In  consequence  of  the  nature 
of  the  soil  in  that  district,  in  wliich  there  is  a  great  quantity  of  limestone,  the  mahogany  is 
longer  coming  to  maturity,  but,  when  fully  grown,  it  is  of  a  harder  and  firmer  texture  than 
that  which  is  found  in  the  southern  portion  of  the  settlement.  There  is  no  wood  more 
durable  than  mahogany,  and  none  that  is  so  generally  useful.  It  is  stated  in  a  little  book 
called  "  The  Mahogany  Tree,"  that  furniture  is  being  made,  in  the  royal  dockyards,  out  of 
the  beautiful  mahogany  found  in  breaking  up  the  old  line-of-battle  ship  the  Gibraltar,  which 
was  built  in  Havana  100  years  ago.  The  English  and  French  governments  purchased  3'ear- 
ly  a  large  amount  of  mahogany  for  their  dockyards.  During  the  last  year  the  British 
government  required  12,000  tons,  paying  £10  17-s.  Gd.  per  ton.  The  French  government 
took  3000  tons  at  the  same  price.  The  royal  yacht  is  built  principally  of  Honduras 
mahogany.  Private  shipbuilders  are,  however,  reluctant  to  make  use  of  mahogany  for 
their  vessels,  as  Lloyd's  Committee  exclude  all  ships  of  12  years'  standing,  in  which  the 
floors,  futtocks,  toptimber,  keelson,  stem  and  stern  post,  transoms,  knightheads,  hawse  tim- 
bers, apron,  and  dead  wood  are  made  of  mahogany. 

"  Mahogany  vessels  of  10  years'  standing  they  admit,  but  even  these,  I  am  informed,  it 
is  their  intention  very  shortly  to  exclude.  The  reason  which  they  assign  is,  that  mahogany 
differs  very  much  in  quality,  and  it  is  impossible  to  know  when  a  ship  is  built  of  good  or 
bad  wood.  But  this  difference  in  quality  depends  entirely  upon  the  district  in  which  it  has 
grown.  If  they  restricted  the  shipbuilders  to  the  northern  wood,  they  might  admit  vessels 
of  12  years'  standing  without  any  risk.  In  the  year  1846  the  Honduras  merchants  present- 
ed a  memorial  to  Lloyd's  Committee,  praying  for  a  removal  of  the  existing  limitations  to 
the  general  use  of  mahogany  in  the  building  of  vessels  of  the  highest  class.  Attached  to 
this  memorial,  were  numerous  certificates  from  persons  well  qualified  to  give  an  opinion  on 
the  subject,  speaking  in  the  highest  terms  of  mahogany  for  shipbuilding.  Captain  E.  Chap- 
pel,  II.  N.,  Secretary  of  the  Royal  Mail  Steam-Packet  Company  says  he  has  seen  '  the  Gibral- 
tar, 80-gun  ship,  which  was  broken  up  at  Pemt)roke.  27iis  s/iip  is  entirch/  of  mnhofianji ; 
captured  of  tlie  Spaniards  in  1780,  all  her  titnbers  sound  as  wfnn  put  into  her.  Tallies  for 
the  navy  made  of  the  timbers  of  the  Gibraltar.  The  Steamer  Forth,  built  liy  Mr.  Menzics 
of  Leith,ha.s  as  much  mahogany  put  into  her  as  could  be  obtained.  The  use  of  mahogany 
ought  to  be  the  rule,  and  not  the  excention.'  The  qualities  of  mahogany,  whicli  lender 
it  so  peculiarly  fitted  for  shipbuilding,  are  its  lightness  and  buoyancy,  its  freedom  from  dry 
rot,  and  its  non-liability  to  shrink  or  warp.  The  price  of  mahogany  varies  according  to  the 
size,  figure,  and  quality  of  the  wood.  One  tree  from  the  northern  districts,  which  was  cut 
into  three  logs,  sold  for  £1800,  or  lO.v.  per  superficial  foot  of  1  inch;  southern  wood  of 
small  size  and  inferior  quality  has  been  sold  at  31(/.  afoot.  The  present  prices  in  London 
for  small-size  plain  mahogany  are  5d.  to  6(/.  jjcr  foot ;  for  large-size  plain,  from  Id.  to  lOd. ; 
and  for  large,  of  good  quality  and  figured,  from  9d.  to  Is.  i'td. 

"  The  yearly  average  quantity  of  mahogany  exported  from  Honduras  during  the  last 
Vol..  IIL— 47 


738 


MALM  EOCK. 


ten  years  is  about  eight  millions  of  feet,  equal  to  20,000  tons,  or  200,000  tons  in  the  whole 
ten  years,  requiring  160,000  trees." 

MALM  ROCK.  A  local  name  for  the  sandstones  of  Surrey  and  Sussex,  called  also 
fire  atone. 

MAMMER.  A  tree  growing  in  Honduras.  Its  dried  leaves  are  very  powerfully 
narcotic ;  the  bark  is,  however,  stated  to  possess  some  tonic  properties.  The  flowers  of  the 
tree  arc  used  in  flavoring  a  liqueur  made  in  some  parts  of  the  West  Indies  called  creine 
(ks  Creoles. — Temple. 

MANCIIINEEL.  A  large  tree  of  a  very  poisonous  character,  growing  in  South  Amer- 
ica, and  in  some  j)arts  of  the  West  Indies.  The  wood  is  of  a  yellow-brown  color,  beauti- 
fully clouded,  and  very  close  and  hard.     It  is  sometimes  used  instead  of  mahogany. 

MANDIOCA.     Cassava  starch.     See  Starch. 

MANURE,  ARTIFICIAL.  Agricultural  writers  usually  divide  manures  into  two 
classes,  natural  and  artificial. 

The  first  division  includes  farmyard  manure,  liquid  manure,  and  the  various  composts 
that  are  occasionally  made  by  farmers  from  excrcmentitious  matters,  earth,  lime,  and  all 
sorts  of  refuse  matters  found  or  produced  on  the  farm. 

In  the  second  division  we  find  guano,  bone  dust,  nitrate  of  soda,  sulphate  of  ammonia; 
also  the  waste  of  slaughter-houses,  night-.soil,  the  refuse  of  glue-makers,  wool  waste,  and 
other  refuse  materials  of  certain  factories ;  and  likewise  superphosphate  of  lime,  blood, 
manure,  and  a  great  variety  of  saline  mixtures,  which  are  now  extensively  manufactured  in 
manure  works,  for  the  purpose  of  supplying  farmers  with  special  chemical  fertilizers,  such 
as  wheat-,  barley-,  oat-,  potato-,  flax-manure,  &c.  The  term  artificial  manure  thus  includes 
a  great  variety  of  difierent  materials,  and  is  frequently  applied  to  products  which,  like 
guano,  are  in  point  of  fact  much  more  natural  tlran  farmyard  manure,  in  the  successful 
preparation  of  which  a  certain  amount  of  skill  is  required  on  the  part  of  the  farmer.  The 
evident  anomaly  of  considering  guano,  bones,  blood,  and  nitrate  of  soda  (Chili  saltpetre)  as 
artificial  manures,  has  led  some  agricultural  writers  to  describe  them  under  natural  ma- 
nures. Again,  others  apply  the  term  artificial  only  to  compound  saline  manuring  mixtures, 
such  as  wheat  and  grass  manures,  or  to  manures  the  preparation  of  which  necessitates  a 
certain  acquaintance  with  chemical  principles  and  the  use  of  chemical  agents.  All  this 
confusion  can  be  avoided  entirely,  if  manures,  instead  of  being  divided  into  natural  and 
artificial,  were  separated  into  home-made  manures,  that  is,  manures  produced  from  the 
natural  resources  of  the  farm,  and  into  imported  manures,  that  is,  fertilizers  which  are 
introduced  on  the  farm  from  foreign  sources. 

The  term  "artificial,"  more  appropriately,  is  given  to  all  simple  or  compound  fertilizers 
in  the  production  of  which  human  art  has  been  instrumental.  In  this  signification  we  shall 
use  the  term  artificial  manure. 

Not  many  years  ago  farmyard  manure  was  universally  considered  the  only  eflScient 
fertilizer  to  restore  the  fertility  of  land,  impaired  by  a  succession  of  crops.  Recent  agri- 
cultural experience,  however,  has  shown  that,  in  a  great  measure,  artificial  manures  may 
be  employed  with  advantage  instead  of  yard  manure,  nay,  that  in  several  respects  artificial 
manures  are  preferable  to  ordinary  dung.  Indeed  the  present  advanced  state  of  British 
agriculture  is  intimately  connected  with  the  success  with  which  artificial  manures  have  been 
introduced  into  the  ordinary  routine  on  the  farm. 

The  variety  of  artificials  in  present  use  amongrt  English  farmers  is  very  great.  Some, 
like  well  prepared  samples  of  superphosphate,  are  unquestionably  manures  distinguished 
for  high  fertilizing  properties ;  otheis  are  less  efficacious,  or  of  a  doubtful  character ;  and 
not  a  few  hardly  repay  the  cost  of  carriage  beyond  a  distance  of  10  miles.  The  fact  that 
in  almost  every  market-town  artificial  manures  are  sold,  which,  if  not  altogether  worthless, 
offer,  to  say  the  least,  no  profitable  investment  to  the  occupier  of  land,  shows  plainly  that 
the  principles  which  ought  to  regulate  the  manufacture  of  artificial  manures  are  not  so 
generally  understood  as  it  is  desirable  they  should  be.  In  comparison  wilh  other  branches 
(;f  industrial  art,  the  manufacture  of  manures  is  comparatively  simple,  and  involves  no  very 
expensive  machinery  l)eyond  steam  power  for  the  pulverization  of  the  raw  materials;  nor 
does  it  necessitate  extensive  practical  expeiience,  or  the  possession  of  a  large  stock  of  chemi- 
cal knowledge,  on  the  part  of  the  manufacturer.  The  limits  of  this  article  preclude  the  detail- 
ed description  of  all  the  artificial  manures  that  find  their  way  at  present  into  the  manure 
market;  nor  does  it  appear  to  us  necessary  to  mention  in  detail  the  various  proportions  in 
which  the  numerous  refuse  materials  used  by  manure-makers  may  be  blended  together  into 
efficacious  fertilizers,  for  a  manufacturer  who  is  thoroughly  acciuainted  with  the  nature  of 
artificial  manures,  and  the  legitimate  uses  to  which  they  ought  to  be  applied,  will  find  little 
or  no  difficulty  when  working  up  into  artificial  manures  the  raw  materials  or  refuse  matters 
for  the  acquirement  of  which  a  particular  locality  may  offer  peculiar  advantages.  A  right 
conception  of  the  relative  commercial  and  agricultural  value  of  the  different  constituents 
that  enter  into  the  composition  of  manures  is  the  chief  desideratum  for  the  manufacturer  of 
artificial  manures.     We  therefore  propose  to  refer,  in  the  following  pages,  briefly  to  the 


MANUEE,  ARTIFICIAL.  739 

more  important  principles  whicli  ought  to  be  kept  steadily  in  view  in  establisliments  erect- 
ed for  tlie  supply  of  artificial  fertilizers. 

The  high  esteem  in  which  good  farmyard  manure  is  held  by  practical  men,  its  uniformly 
beneficial  effect  upon  almost  every  kind-of  crop,  and  the  economical  advantages  with  which 
it  is  usually  applied  to  the  land,  have  induced  many  to  regard  farmyard  manure  as  the 
model  which  the  manuf\icturer  of  aitificial  manure  should  endeavor  to  imitate.  But  this 
proposition  is  wrong  in  principle,  as  will  be  shown  presently,  and  its  adoption  in  manure 
works  has  led  to  disappointment  find  ruin.  It  would  be  foreign  to  our  object  to  give  in  this 
place  a  full  account  of  the  peculiar  merits  that  belong  to  j'ard  manure,  and  to  compare 
them  with  those  exhibited  by  artificial  manures.  Each  has  its  peculiar  merits  and  dis- 
advantages, upon  which  we  need  not  dwell  in  this  article. 

Farmyard  manure  contains  all  the  constituents  which  our  cultivated  crops  require  to 
come  to  perfection,  and  is  suited  for  every  description  of  agricultural  produce.  As  far  as 
the  inorganic  fertilizing  substances  are  concerned,  we  find  in  farmyard  manure  potash,  soda, 
lime,  magnesia,  oxide  of  iron,  phosphoric  acid,  sulphuric  acid,  hydrochloric  and  carbonic 
acid,  in  short  all  the  minerals  that  are  found  in  the  ashes  of  agricultural  crops. 

Of  organic  fertilizing  substances,  we  find  in  farmyard  manure  some  which  are  readily 
soluble  in  water,  and  containing  a  large  portion  of  nitrogen  ;  and  others  insoluble  in  water, 
and  containing,  comparatively  speaking,  a  small  proportion  of  nitrogen.  The  former  readi- 
ly yield  ammonia,  the  latter  principally  give  rise  to  the  formation  of  Immic  acids,  and  simi- 
lar organic  compounds.  These  organic  acids  constitute  the  mixture  of  organic  matters, 
which  in  practice  pass  under  the  name  of  humus. 

Farmyard  manure  thus  is  a  perfect  manure,  for  experience  and  analysis  alike  shows  that 
it  contains  all  the  fertilizing  constituents  required  by  plants,  in  states  of  combination  wliich 
appear  to  be  especially  favorable  to  the  luxuriant  growth  of  our  crops. 

On  most  farms,  the  supply  of  common  yard  manure  is  inadequate  to  meet  the  demands 
of  the  modern  system  of  high  farming.  Hence  the  endeavor  of  enterprising  men  to  supply 
this  deficiency  by  converting  various  refuse  materials  into  substitutes  for  farmyard  manure. 
Artificial  manures,  likely  to  appi'oach  farmyard  manure  in  their  action,  should  contain  all 
the  elements  in  the  latter,  and  in  a  state  of  combination,  in  which  they  are  neither  too 
soluble  nor  too  insoluble ;  for  it  is  evident  that  a  plant  can  grow  lu.^uriantly,  and  come  to 
perfect  maturity,  only  when  all  the  elements  necessary  for  its  existence  are  presented  to  it 
in  a  state  in  which  they  can  be  assimilated  by  the  plant. 

But  the  question  arises.  Is  it  desirable  to  produce  by  art  perfect  substitutes  for  common 
dung  ?     We  think  not,  for  the  following  reasons : — 

In  the  first  place,  well  rotted  dung  contains  in  round  numbers  two  thirds  of  its  weight  of 
water,  and  only  one  third  of  its  weight  of  dry  matter.  A  large  bulk  therefore  contains, 
comparatively  speaking,  but  a  small  proportion  of  fertilizing  matters.  In  every  3  tons  of 
manure  we  have  to  pay  carriage  for  2  tons  of  water,  and  it  may  be  safely  asserted  that  no 
manure,  however  efficacious  it  may  be  in  a  dry  condition,  will  be  found  an  economic  substi- 
tute for  farmyard  manure,  if  it  cannot  be  produced  in  a  much  drier  condition  than  common 
yard  manure. 

Again,  several  of  the  constituents  which  greatly  preponderate  in  farmj'ard  manure  are 
present  in  most  soils  in  abundant  (juantities ;  they  need  not,  therefore,  be  supplied  to  the 
land  in  the  form  of  manure ;  or,  should  they  be  wanting  in  the  soil,  they  can  be  readily  ob- 
tained almost  everywhere  at  a  cheap  rate.  If,  therefore,  these  inexpensive  and  more  wide- 
ly distributed  substances  are  dispensed  with  in  compounding  a  manure,  and  those  are 
selected  which  occur  in  .soils  only  in  minute  quantities,  a  very  valualjle  and  efficacious 
fertilizer  is  obtained,  which  possesses  the  great  advantage  of  containing  in  a  small  bulk  all 
the  essential  fertilizing  sul)stances  of  a  large  mass  of  home-made  dung. 

That  the  effect  whicli  ijvery  description  of  manure  is  capable  of  producing  depends  on 
its  composition  is  self-evident ;  and  as  the  dilferent  constituents  which  generally  enter  into 
the  composition  of  manures  produce  different  effects  upon  vegetation,  it  is  of  {irimary  im- 
portance to  the  manufacturer  of  manure  that  he  should  be  accpiainted  with  the  special 
mode  of  action  of  each  fertilizing  con.stituent. 

We  shall  therefore  make  some  obsei'vations  on  the  practical  eflects,  and  the  compara- 
tive value,  of  the  various  constituents  that  enter  into  the  com])osition  of  man>n-es. 

To  guard  against  misapprehension,  we  would  observe  that,  in  one  sense,  all  the  fertiliz- 
ing agents  are  alike  valuable ;  for  they  are  all  indispensai)le  for  the  healthy  condition  of  our 
cultivated  crops,  and,  consequently,  the  absence  of  one  is  attended  with  seiious  I'oiiseciuences, 
though  all  others  may  be  present  in  abmulaiu'e.  Thus  the  deficiency  of  lime  in  the  land  is 
attended  with  as  much  injury  to  the  plant  iw  that  of  |)h()sphoric  acid.  In  this  sense  lime  is 
as  valuable  a.s  ])hosphoric  acid ;  but  ina.smuch  as  lime  is  generally  found  in  most  soils 
in  abundant  (|tiantilie.s,  or,  if  deficient,  can  be  applied  to  the  land  economically  in  the  form 
of  slackeil  lim(>,  marl,  shell  sand,  &c.,  its  presence  in  an  artificial  manure  is  by  no  means  a 
recommendation  to  it. 

The  principal  constituents  of  Manures  arc  : — 


Y40 


MANURE,  ARTIFICIAL. 


1.  Nitrogen  (in  the  shape  of  ammonia,  nitric  acid,  and  nitrogenized  organic  matters.) 

2.  Phosphoric  acid  (bone-earth  and  soluble  phosphates.) 

3.  Potash  (carbonate  and  silicate  of  potash.) 

4.  Soda  (common  salt.) 

5.  Lime  and  magnesia  (carbonate  and  sulphate  of  lime  and  magnesia.) 

6.  Soluble  silica. 

7.  Humus,  forming  organic  matters  (vegetable  remains  of  all  kinds.) 

8.  Sulphuric  acid  (sulphate  of  lime.) 

9.  Chlorine  (common  salt.) 

10.  Oxide  of  iron,  alumina,  silica  (clay,  earth,  and  sand.) 

AVe  have  here  mentioned  these  constituents  in  the  order  which  expresses  their  compara- 
tive commercial  value. 

1.  Nitrogen. — This  element  may  be  incorporated  with  artificial  manures  in  the  shape  of 
ammoniacal  salts  or  nitrates,  or  nitrogenized  organic  matters. 

The  cheapest  ammoniacal  salt  is  sulphate  of  ammonia  ;  the  cheapest  nitrate  is  Chili  salt- 
petre, or  nitrate  of  soda ;  hence  sulphate  of  ammonia  and  nitrate  of  soda  are  exclusively 
employed  by  manure  manufacturers  for  the  preparation  of  nitrogenized  manures,  when  no 
organic  refuse  matters  containing  nitrogen,  such  as  horn-shavings,  bone-dust,  woollen  rags, 
blood,  glue  refuse,  &c.,  are  availiable. 

Nitrogen  in  any  of  these  forms  exercises  a  most  powerful  action  in  manure,  especially 
when  applied  to  plants  at  an  early  stage  of  their  growth  ;  at  a  later  period  of  development 
the  application  of  ammoniacal  salts  or  nitrate  of  soda  appears  much  less  effective,  and  some- 
times even  useless.  For  this  reason  nitrogenized  manures,  such  as  guano,  soot,  specially 
prepared  wheat  manures,  &c.,  ought  to  be  applied  either  in  autumn  or  in  spring,  immediate- 
ly after  the  young  blade  has  made  its  appearance  above  ground. 

Ammoniacal  salts,  nitrate  of  soda,  and  decomposed  nitrogenized  organic  matters  have 
a  most  marked  effect  upon  the  leaves  of  plants,  they  induce  a  rapid  and  luxuriant  develop- 
ment of  leaves,  and  may  therefore  be  called  leaf-producing  or  forcing  manures.  Grass, 
wheat,  oats,  and  other  cereals,  when  grown  upon  soils  containing  abundance  of  available 
mineral  elements,  are  strikingly  benefited  by  a  nitrogenized  manure ;  but,  on  account  of 
their  special  action,  they  ought  to  be  used  with  caution  in  the  case  of  corn-crops,  and  always 
more  sparingly  on  light  than  on  heavy  land ;  otherwise,  fine  straw,  but  little  and  an  inferior 
sample  of  grain,  will  be  obtained. 

As  a  general  rule,  ammoniacal  salts  or  nitrate  of  soda  should  not  be  used  by  farmers  in 
a  concentrated  state,  and  exceptionally  only.  However  useful  sulphate  of  ammonia  or 
nitrate  of  soda  may  be  in  a  particular  case,  it  ought  to  be  remembered  that  generally  such 
manures  produce  beneficial  effects  only  in  conjunction  with  mineral  matters.  If,  there- 
fore, a  proper  amount  of  available  mineral  substances  does  not  exist  in  the  soil,  it  has  to 
be  supplied  in  the  manure.  Ammoniacal  salts,  nitrate  of  soda,  animal  matters,  &c.,  are 
therefore  almost  always  blended  together  with  phosphates,  common  salt,  gypsum,  &c.,  by 
manufacturers  of  manures. 

Whilst  we  thus  fully  recognize  the  importance  of  the  presence  of  ammonia,  ammoniacal 
salts,  nitrates,  or  animal  matters  furnishing  ammonia  on  decomposition  in  manures,  especial- 
ly in  manures  for  white  crops,  we  cannot  agree  with  those  who  estimate  the  entire  value  of 
manuring  substances  by  the  proportion  of  nitrogen  which  they  contain. 

In  a  purely  commercial  sense,  nitrogen  in  the  shape  of  ammonia  or  nitric  acid,  or 
animal  nitrogenized  matters,  is  the  most  valuable  fertilizing  constituent,  for  it  fetches  a 
higher  price  in  the  market  than  any  other  manuring  constituent. 

2.  Phosphoric  acid. — Next  in  importance  follows  phosphoric  acid.  This  acid  exists 
largely  in  the  grain  of  wheat,  oats,  barley,  in  leguminous  seeds,  likewise  in  turnips,  man- 
golds, carrots,  in  clover,  meadow-hay,  and,  in  short,  in  every  kind  of  agricultural  produce. 
Whether  we  grow,  therefore,  a  cereal  crop  or  a  fallow  crop,  there  must  be  phosphoric  acid 
in  sufficient  quantity  in  the  soil,  or  if  insufficient  it  must  be  added  to  the  land  in  the  shape 
of  manure. 

The  proportion  of  phosphoric  acid  in  even  good  soils  is  very  small,  and  as  the  agri- 
cultural produce  in  almost  every  case  removes  from  the  soil  more  of  phosphoric  acid  than 
of  any  other  soil-constituent,  the  want  of  available  phosphoric  acid  makes  itself  known  very 
soon.  This  is  especially  the  case  with  quick-growing  crops,  such  as  turnips,  mangolds,  &c. 
The  whole  period  of  vegetation  of  these  green  crops  extends  only  over  four  or  five  months, 
and  the  fibrous  roots  of  these  crops  are  unable  to  penetrate  like  wheat  the  soil  to  any  con- 
siderable depth.  For  these  reasons  phosphoric  acid  in  some  form  or  other  has  to  be 
abundantly  supplied  to  root-crops ;  and  experience  has  shown  that  no  description  of  fertiliz- 
ing matter  benefits  .so  much  roots  as  super-])hosphate  and  similiar  manures,  which  contain 
phosphate  of  lime  in  a  state  in  which  it  is  readily  a.«similated  by  plants. 

In  artificial  manures,  phosphoric  acid  commonly  occurs  in  the  shape  of  bone-dust,  boiled 
bones,  bone-shaving  (refuse  of  knife-handle  makers,  turners  of  ivory,  button-makers,  &c.,) 
or  in  the  state  of  bi-phosphate  of  lime,  purposely  manufactured  from  bone-materials  or 
from  phosphatic  minerals. 


MANURE,  ARTIFICIAL.  741 

The  phosphate  of  lime  which  occurs  in  fresh  bone,  practically  speaking,  is  insoluble  in 
water.  In  water  charged  with  carbonic  acid,  and  still  more  so  in  water  containing  some 
ammonia,  it  is  more  soluble  than  in  pure  water.  On  fermenting  bone-dust  in  heaps,  it  be- 
comes a  much  more  effective  manure.  Such  fermented  bone-dust  is  added  with  much 
benefit  to  general  artificial  manures. 

All  really  good  artificial  manures  should  contain  a  fair  proportion  of  phosphate — say 
from  25  to  40  per  cent.,  according  to  the  uses  for  which  the  manure  is  intended.  General- 
ly speaking,  manures  for  turnips,  and  root-crops  in  general,  should  be  rich  in  phosphates, 
especially  soluble  phosphates,  (bi-phosphate  of  lime ;)  such  manures  need  not  contain  more 
than  I  to  li  per  cent,  of  ammonia,  and,  when  used  on  land  in  a  tolerably  good  agricultural 
condition,  ammonia  can  l)e  altogether  omitted  in  the  manure  without  fear  of  deteriorating 
the  efficacy  of  the  manure. 

3.  Potash. — Salts  of  potash  unquestionably  are  valuable  fertilizing  constituents,  for 
potash  enters  largely  into  the  composition  of  the  ashes  of  all  crops.  Root-crops  especially 
require  much  potash ;  hence  these  crops  are  much  benefited  by  wood  ashes,  burnt  clay, 
liquid  manure,  and  other  fertilizers  containing  much  potash. 

The  commercial  resources  of  potash  are  limited,  and  salts  of  potash  without  exception 
far  too  expensive  to  be  employed  largely  in  the  manufacture  of  artificial  manures.  Potash 
consequently  is  rarely  found  in  artificial  manures.  Fortunately,  potash  exists  abundantly 
in  most  soils  containing  a  fair  proportion  of  clay.  Its  want  in  artificial  manures  therefore 
is  not  perceived,  at  least  not  in  the  same  degree  in  which  the  deficiency  of  phosphates  in  a 
manure  would  be  felt. 

4.  Soda. — Salts  of  soda  arc  much  less  efficacious  fertilizing  matters  than  salts  of  potash. 
There  are  few  soils  which  do  not  contain  naturally  enough  soda,  in  one  form  or  the  other, 
to  satisfy  the  wants  of  the  crops  which  are  raised  upon  them.  However,  common  salt  is 
largely  employed  in  the  manufacture  of  artificial  manures  ;  if  it  does  no  good,  it  certainly 
does  no  harm,  and  in  this  «ountry  is  one  of  the  cheapest  diluents  which  can  be  employed 
for  reducing  the  expenses  of  concentrated  fertilizing  mixtures  to  a  price  at  which  they  can 
be  sold  to  farmers.  In  Continental  districts  common  salt  proves  more  efficacious  as  a 
manure  than  in  England,  where  the  neighborhood  of  the  sea  provides  the  majority  of  soils 
with  plenty  of  salt,  which  by  the  winds  is  carried  landwards  with  the  spray  of  the  sea  to 
very  considerable  distances. 

Salt,  however,  even  in  England,  is  usefully  applied  to  mangolds,  and  enters  largely  into 
the  composition  of  most  artificial  manures  expressly  prepared  for  this  crop. 

5.  Lime  and  Magnesia. — All  plants  require  lime  and  magnesia  in  smaller  or  larger 
quantities.  Many  soils  contain  lime  in  superabundance ;  in  otiiers  it  is  deficient.  To  the 
latter  soils  it  must  be  added.  This  can  be  done  by  lime-compost,  by  slaked  lime,  by  marl, 
shell-sand,  or  gypsum.  All  these  calcareous  manures  are  cheap  almost  everywhere,  for  lime 
and  magnesia  are  among  the  most  widely  distributed,  and  most  abundant  mineral  substances. 

The  addition  of  chalk,  marl,  and  even  gypsum,  to  artificial  manures,  should  therefore 
be  avoided  as  much  as  possible. 

At  the  best,  carbonate  and  sulphate  of  lime  in  artificial  manures  must  be  regarded  as 
diluents. 

6.  Soluble  Silica  The  artificial  supply  of  soluble  silica  to  the  land,  as  far  as  our 
present  experience  goes,  has  done  no  good  whatever  to  cereals,  the  straw  of  which  soluble 
silica  is  supposed  to  strengthen. 

In  the  absence  of  reliable  practical  experiments  with  soluble  silica,  we  cannot  venture 
to  recommend  the  use  of  silicate  of  soda,  or  soluble  silica  to  manure  manufacturers. 

7.  Organic  substances,  Humus  — The  importance  of  organic  matters  free  from  nitrogen, 
as  fertilizing  agents,  is  very  trifling.  Formerly  the  value  of  a  manure  was  estimated  by  the 
amount  of  organic  matter  it  contained,  and  little  or  no  difierence  was  made  whether  the 
organic  matter  contained  nitrogen  or  not.  Under  good  cultivation,  the  organic  matter  in  the 
soil  regularly  increases  from  year  to  year ;  there  exists  therefore  no  necessity  of  supplying 
it  in  the  shape  of  manure. 

In  artificial  manures  we  should  certainly  exclude  all  substances  that  merely  add  to  the 
bulk,  without  enhancing  the  real  fertilizing  value  of  the  manure.  Peat,  saw-dust,  and 
similar  organic  matters,  &c.,  are  useful  to  the  manure-maker  only  as  diluents  and  absorb- 
ents of  moisture. 

8.  Sulphuric  acid  is  another  constituent  of  manure,  which  possesses  little  value.  In 
artificial  manures  sulphuric  acid  chiefly  occurs  as  gypsum. 

9.  Chlorine  exists  in  manures  principally  as  salt. 

10.  Oxitlc  of  iron,  Alumina,  Silica. — These  constituents  exist  sometimes  in  manures 
in  the  shape  of  burnt-clay,  earth,  brick-dust,  and  sand. 

It  is  hardly  necessary  to  remark  that  good  artificial  manures  should  contain  as  little  as 
possible  of  tiiese  mattei-s. 

It  will  api)ear  from  the  preceding  observations,  that  nitrogen  in  the  shape  of  ammonia- 
cal  salts,  nitiic  acid  or  decomposed  animal  matters,  and  phosphoric  acid  are  the  most 
valuable  fortili/.ing  constituents. 


742  MANUKE,  ARTIFICIAL. 

The  maniifiicturers  of  artificial  manures  should  therefore  endeavor: 

1.  To  jjroduce  manures  containing  as  little  water  as  possible. 

2.  To  incorporate  as  much  of  nitrogenized  organic  matters,  or  ammoniacal  salts,  ot 
nitrates  and  phosphates,  in  general  manuring  mixtures,  as  is  possible  at  the  price  at  which 
artificial  manures  are  usually  sold. 

3.  To  avoid  as  much  as  possible,  gypsum,  salt,  peat-mould,  chalk,  and  other  substances 
that  chiefly  add  to  the  bulk,  without  increasing  the  efficacy,  of  the  manures. 

He  should  also  endeavor  to  produce  uniform  finely  pulverized  articles,  that  run  readily 
through  the  manure  drill. 

It  likewise  devolves  on  the  manufacturer  of  manures  to  render  more  effective,  that  is  to 
s;iy,  more  rapid  and  energetic  in  their  action,  refuse  materials  which  may  remain  inactive 
in  the  soil  for  years  before  they  enter  into  decomposition,  and  to  reduce  by  chemical  means 
into  a  more  convenient  state  for  assimilation,  raw  materials,  which  like  coprolites,  apatite, 
&.C.,  produce  little  or  no  beneficial  effects  upon  vegetation,  even  when  added  to  the  land 
in  a  finely  powdered  condition. 

At  the  present  time,  two  classes  of  artificial  manures  may  be  distinguished  :  1,  general 
maiHires,  i.  e.  manures  which  profess  to  .suit  equally  well  every  kind  of  agricultural  pro- 
duce ;  and  2,  specially  prepared  for  a  particular  crop  only. 

The  requirements  of  different  crops,  or  perhaps,  more  correctly  speaking,  the  conditions 
that  legulate  the  a.ssimilation  of  food,  vary  so  much,  that  we  doubt  the  policy  of  manure- 
makers  to  prepare  general  artificial  manures.  At  the  same  time,  we  doubt  the  necessity 
of  preparing  artificial  manures  for  eveiy  description  of  crop.  Special  manures  are  extreme- 
ly useful  to  faimers,  if  they  are  prepared  by  intelligent  manufacturers,  who  possess  suf- 
ficient chemical  knowledge  to  take  advantage  of  every  improvement  that  is  made  in 
manufacturing  chemistry,  and  at  the  same  time  know  sufficient  of  agriculture  to  understand 
what  is  really  wanted  in  a  soil.  In  other  words,  except  a  manufacturer  is  a  good  practical 
chemist,  and  a  tolerably  good  farmer,  he  will  not  be  able  properly  to  adapt  the  compo.sition 
of  special  fertilizers  to  the  nature  of  the  soil,  and  the  peculiar  mode  of  treatment  which  the 
land  lias  received  on  the  part  of  the  farmer. 

However,  nearly  all  special  artificial  manincs,  generally  speaking,  may  be  arranged 
under  two  heads.     They  are  either:  I.  Nitrogenized  Manures,  or,  2.  Phosphatic  Manures. 

The  first  may  l)e  used  with  almost  equal  advantage  for  wheat,  barley,  oats,  for  rye,  and 
on  good  land  likewise  for  grass. 

The  second  are  chiefly  used  for  root-crops. 

Nitrogenized  artificial  manures  frequently  are  nothing  more  than  guano,  diluted  with 
gypsum,  salt,  peat-mould,  earth,  &c.  In  fact,  guano  is  the  cheapest  ammoniacal  manure, 
for  which  reason  it  is  so  largely  employed  for  compounding  low-priced  wheat  manures, 
grass  manures,  &c.,  &c. 

Good  manures  for  cereals  may  be  made  by  blending  together  fine  bone-dust,  or  bone- 
dust  dissolved  in  sulphuric  acid,  sulphate  of  ammonia,  salt  and  gypsum.  These  manures 
will  be  the  better  the  more  sulphate  of  ammonia   they  contain. 

Turnip-manures,  and  artificial  manures  for  root-crops  in  general,  consist  principally  of 
dissolved  bones,  or  dissolved  coprolites  and  other  mineral  phosphates.  They  are,  in  fact, 
superphosphates  of  various  degrees  of  concentration.  The  more  soluble  phosphate  a  root- 
manure  contains,  the  better  it  is  adapted  to  the  purpose  for  which  it  is  used. 

Most  samples  of  superphosphate  contain  little  or  no  ammonia,  or  nitrogenized  organic 
matters. 

Others  sold  under  the  name  of  nitro-  or  ammonia-phosphate,  in  addition  to  soluble  and 
insoluble  pliosphate,  contain  some  ammonia  and  organic  matters. 

Blood  manure  is  a  superpiiosphate,  in  the  pi-eparation  of  which  some  blood  is  used. 

In  preparing  superphosphate  from  bones,  it  is  essential  that  they  should  be  reduced  to 
fine  dust.  Tiiis  is  moistened  with  about  i^  its  weight  of  water,  after  which  another  third  to 
one-half  of  brown  sulphmic  acid  is  added.  The  pasty  mass  is  allowed  to  cool,  in  the  mix- 
ing vessel,  or  when  large  (|uantities  ai'c  i)rc|)arcd,  the  semi-liquid  mass  in  the  mixer  is  lun 
out  still  hot,  fresh  (piantities  of  Ixuie-dust,  water,  and  acid  are  put  in  the  mixer,  and  after 
5  or  lt>  minutes  the  contents  allowed  to  run  out,  and  a  fresh  quantity  prepared  as  before. 
The  successive  mixings  are  all  kept  together  in  one  heap  for  1  or  2  months ;  the  heap  is 
then  turned  over  and,  if  necessary,  the  partially  di.ssolved  bones  tire  pa.s.sed  through  a  riddle. 

In  a  similar  manner,  coprolites,  bone-a.sh,  apatite  aiul  other  jjhosphatic  minerals  are 
treated  with  acid.  It  ought  to  be  observed,  however,  that  the  (|uantity  of  liiown  sulphuric 
acid  necessary  f<u'  di.ssolving  coprolites  must  be  at  least  f  of  the  weight  of  coprolite  pow- 
der, for  coprolites  contain  much  carbonate  of  lime,  which  neutralizes  sulphuiic  acid.  Even 
'TS  per  cent,  of  l)rown  acid  are  not  always  sullicieiit  to  dissolve  completely  coprolite  powder, 
aTul  as  the  proportion  of  carbonate  of  lime  in  coprolites  and  sulf)huiic  minerals  varies  con- 
siderably, it  cannot  be  stated  definitely  what  amount  of  oil  of  vitriol  should  be  used  in  every 
cpse.  The  safest  f)lan,  therefore,  for  the  manufacturer  is,  to  ascertain  from  time  to  time 
whether  the  proportion  of  acid  which  he  has  used   has  converted  nearly  the  whole  of  the 


MERCURY  OB  QUICKSILVER.  743 

insoluble  phosphates  in  coprolites  into  soluble  phosphates,  and  if  necessary  to  add  more  acid. 
In  the  case  of  bone-dust,  it  docs  not  matter  if  the  whole  of  the  bone-earth  is  not  rendered 
soluble ;  bones  even  partially  acted  upon  by  oil  of  vitriol,  become  sufficiently  soluble  in  the 
soil  to  prove  efficacious  for  the  turnip  crop.  But  the  case  is  different,  if  mineral  phos- 
phates, such  as  apatite  or  coprolite  powder,  are  employed  in  the  manufacture  of  super- 
phosphate. Insoluble  phosphates  in  the  shape  of  coprolite  powder  are  not  worth  any  thing 
in  an  artificial  manure,  for  they  are  too  insoluble  to  be  taken  up  by  the  turnip  crop.  It  is 
therefore  essential  to  employ  a  quantity  of  acid,  which  is  amply  sufficient  to  convert  the 
whole  of  the  insoluble  phosphate  of  lime  in  coprolites  into  soluble,  as  biphosphate  of  lime. 
See  Coprolites. — A.  V. 

MELAMINE.  CH^N*.  An  alkali  produced  from  melam  under  the  influence  of  boil- 
ing potash.  It  is  isomeric  with  cyanamide,  from  which  it  may  be  produced  by  the  action 
of  heat.— G.  G.  W. 

MERCURY  or  QUICKSILVER.  Mr.  Russell  Bartlett,  the  United  States  Commissioner 
on  the  Mexican  and  United  States  Boundary  Question,  who  visited  California  in  1853,  states 
that  the  quantity  of  quicksilver  produced  annually  at  New  Almaden,  exceeds  1,000,000  lbs. 
During  the  year  1853  the  total  exports  from  San  Francisco  amounted  to  1,350,000  lbs. 
valued  at  683,189  dollars.  All  this,  together  with  the  large  amount  used  in  California,  was 
the  product  of  the  New  Almaden  mine  in  the  Santa  Clara  county,  12  miles  from  the  town 
of  San  Jose,  which  is  54  miles  from  the  city  of  San  Francisco.  The  working  of  the  mine 
was  begun  in  the  year  1846-7,  by  an  English  company,  but  for  some  reasons  was  not 
profitable.  In  1849-50  it  fell  into  American  hands.  The  following  shows  to  what  points 
the  quicksilver  was  exported  in  1853:— Hong  Kong,  423,150  lbs. ;  Shanghae,  60,900  lbs. ; 
Canton,  27,450  lbs. ;  Whampoa,  22,500  lbs. ;  Calcutta,  3,750  lbs;  Mazatlan,  210,825  lbs.  ; 
Mazatlan  and  San  Bla.s,  19,125  lbs;  San  Bias,  145,652  lbs;  Callao,  135,000  lbs.;  Valpa- 
raiso, 148,275  lbs. ;  New  York,  138,375  lbs.;  Philadelphia,  75,000  lbs.  The  ore  is  cin- 
nabar of  a  bright  vermilion  color.     Its  specific  gravity  is  3,622. 

The  process  by  which  the  fluid  metal  is  extracted  is  one  of  great  simplicity.  There  are 
6  furnaces,  near  which  the  ore  is  deposited  from  the  mine,  and  separated  according  to  its 
quality ;  the  larger  masses  are  first  broken  up,  and  then  all  is  piled  up  under  sheds  near  the 
furnace  doors.  The  ore  is  next  heaped  on  the  furnaces,  and  a  steady  though  not  a  strong 
fire  is  applied ;  as  the  ore  becomes  heated  the  quicksilver  is  sublimed,  and  being  condensed 
it  falls  by  its  own  weight,  and  is  conducted  by  pipes  which  lead  along  the  bottom  of  the 
furnace  to  small  pots  or  reservoirs  imbedded  in  the  earth,  each  containing  from  1  to  2  gal- 
lons of  the  metal.  The  furnaces  are  kept  going  night  and  day,  while  large  drops  or  minute 
streams  of  the  pure  metal  are  constantly  trickling  down  into  the  receivers  ;  from  these  it  is 
carried  to  the  storehouse  and  deposited  in  large  cast-iron  tanks  or  vats,  the  largest  of  which 
is  capable  of  containing  20  tons  of  quicksilver.  Seven  or  eight  days  are  required  to  fill  the 
furnaces,  extract  the  quicksilver,  and  remove  the  residuum.  The  miners  and  those  who 
merely  handle  the  cinnabar  are  not  injured  thereby ;  but  those  who  work  about  the  fur- 
naces and  inhale  the  fumes  of  the  metal  are  seriously  affected.  Salivation  is  common,  and 
the  attendants  on  the  furnaces  are  compelled  to  desist  from  their  labor  every  3  or  4  weeks, 
when  a  fresh  set  of  hands  is  put  on.  The  horses  and  mules  are  also  salivated,  and  from 
20  to  30  of  them  die  every  year  from  the  effects  of  the  mercury. 

The  following  more  detailed  account  of  the  apparatus  for  smelting  is  given  by  Mr.  Rusch- 
enberger : — A  kind  of  reverberatory  furnace  3  feet  by  5  is  arranged  at  the  extremity  of  a 
series  of  chamljers,  of  nearly,  if  not  exactly  of  tlie  same  dimensions,  namely,  7  feet  long, 
4  wide,  and  5  high.  There  are  8  or  10  of  these  chambers  in  each  series;  they  are  built  of 
brick,  plastered  inside,  and  secured  by  iron  rods,  armed  at  tlie  end  with  screws  and  nuts  as 
a  protection  against  the  expansion  by  heat.  The  tops  are  of  boiler  iron  luted  with  ashes 
and  salt.  The  first  chamber  is  for  a  wood  fire.  The  second  is  the  ore  chamber,  which  is 
separated  from  the  first  by  a  net-work  partition  of  brick.  The  flame  of  the  fire  passes 
through  the  square  holes  of  this  partition,  and  plays  upon  the  ore  in  the  ore  chamber, 
which  when  fully  charged  contains  10,000  lbs.  of  cinnabar;  next  to  the  ore  chamber  is  flic 
first  condensing  chamber,  which  comnnmicates  with  it  by  a  square  hole  at  the  right  upper 
corner;  and  tlie  communication  of  this  first  with  the  second  condensing  cliambor  is  liy  a 
square  hole  at  the  left  lower  corner.  An  opening  at  the  right  upper  corner  of  tlie  jiartition, 
between  the  second  and  third  condensing  chamber,  t!onnnuiiicates  with  the  latter.  The 
openings  between  the  chambers  are  at  the  top,  and  to  the  right,  and  at  the  l)ottom,  and  to 
the  left  alternately  ;  so  that  the  vapors  from  the  ore  chamber  are  forced  to  describe  a  spiral 
in  their  passage  through  the  8  condensers.  The  vapor  and  smoke  pass  from  the  last  con- 
densing chamber  through  a  square  wooden  box,  8  or  10  feet  long,  in  which  there  is  a  con- 
tinuous shower  of  cold  water,  and  finally  escape  into  the  oi)en  air  by  tall  wooden  flues. 
The  floor  or  bottom  of  each  condensing  chaiiiber  is  about  2  feet  above  the  ground,  and  is 
arranged  with  gutters  for  collecting  the  condensed  mercury  and  conveying  it  out  into  an 
open  conduit,  along  which  it  flows  into  an  iron  receptacle,  from  which  it  is  poured  into  the 
iron  flasks  through  a  brush  to  cleanse  it  of  tiic  scum  of  oxide  formed  on  the  surface  on 


744  METALLOGRAPHY. 

standin<'.  TO  lbs.  weight  are  poured  into  each  flask.  There  are  14  of  these  furnaces  and 
ran"-es  of  condensers,  with  passages  of  8  or  10  feet  in  widtli  between  them.  A  slied  is  con- 
structed above  the  whole  at  a  suHicient  elevation  to  permit  free  circulation  of  the  air. 

According  to  Duma.s,  the  following  mines  yield  annually  as  follows  : — Alniadcn  in  Spain, 
from  2,700,000  to  3,45(5,000  lbs.  avoirdupois  ;  Idria,  048,000  to  1,080,000  lbs.  ;  Hungary 
and  Transvlvania,  75,000  to  97,200  ;  Deux  Points,  43,000  to  54,000  lbs. ;  Palatinate,  19,44u 
to  2 1,000 'lbs.  ;  Huancavclica,  324,000  lbs. 

METALLOGRAPHY.  A  process  invented  by  M.  Abate,  and  published  by  him  in  1851. 
It  consists  of  printing  from  engraved  wood-blocks  upon  metallic  surfaces,  so  as  to  produce 
imitations  of  figures  and  ornaments  inlaid  in  wood.  This  eftect  he  obtained  by  using,  as  a 
printing  menstruum  to  wet  the  block  with,  solutions  of  such  metallic  or  earthy  salts  as  are 
decomposed  when  brought  into  contact  with  certain  metals,  and  produce,  throiigh  an  elec- 
tro-chemical action,  an  adhesive  precipitate  of  a  colored  metallic  oxide,  or  any  other  chemi- 
cal change  upon  the  metal.  There  are  here  two  principles  at  work  :  the  one  is  the  chemical 
action  just  referred  to  ;  the  other — the  formation  and  key-stone  to  the  invention — rests  in 
the  porousness  of  the  printing  object,  which  causes  the  absorption  of  the  wetting  fluid. 
The  application  of  the  invention  to  printing  upon  vegetable  substances  instead  of  metallic 
surfaces,  required  the  introduction  into  the  process  of  some  other  principle,  to  produce  that 
chemical  change  which  in  metallography  is  spontaneous.  The  following  is  11.  Abate's  de- 
scription of  his  process  : — 

Suppose  a  sheet  of  veneering-wood  to  be  the  object  from  which  impressions  are  to  be 
taken  ;  the  wood  is  exposed  for  a  few  minutes  to  the  cold  evaporation  of  hydrochloric  or  sul- 
phuric acid,  or  is  slightly  wetted  with  either  of  those  acids  diluted,  and  the  acid  is  wiped 
off  from  the  surface.  Afterwards  it  is  laid  upon  a  piece  of  calico,  or  paper,  or  common 
wood,  and  by  a  stroke  of  the  press  an  impression  is  taken,  but  which  is  quite  invisible  ; 
now  by  exposing  this  impression  immediately  to  the  action  of  a  strong  heat,  a  most  perfect 
and  beautiful  representation  of  the  printing  wood  instantaneously  appears.  In  the  same 
wav,  with  the  same  plate  of  wood,  without  any  other  acid  preparation,  a  number  of  impres- 
sions, about  twenty  or  more,  are  taken ;  then,  as  the  acid  begins  to  be  exhausted  and  the 
impressions  faint,  the  acidification  of  the  plate  must  be  repeated  as  above,  and  so  on  pro- 
gressively, as  the  wood  is  not  in  the  least  injured  by  the  working  of  the  process  for  any 
number  of  impressions.  All  these  impressions  show  a  general  wood-like  tint,  most  natural 
for  the  light-colored  woods,  such  as  oak,  walnut,  maple,  &c.,  but  for  other  woods  that  have  a 
peculiar  color,  such  as  mahogany,  rosewood,  &:c.,  the  impression  must  be  taken,  if  a  true 
imitation  be  required,  on  a  stuff  dyed  with  the  right  color  of  the  wood. 

It  must  be  remarked,  that  the  impressions  as  above  made  show  an  inversion  of  tints  in 
reference  to  the  original  wood,  so  that  the  light  are  dark,  and  vice  rersd,  which,  however, 
docs  not  interfere  with  the  effect.  The  reason  of  it  is,  that  all  the  varieties  of  tints  which 
appear  in  the  same  wood  are  the  effect  of  the  varying  closeness  of  its  fibres  in  its  different 
parts,  so  that  where  the  fibres  are  close  the  color  is  dark,  and  light  where  they  are  loose  ; 
but  in  the  above  process,  as  the  absorption  of  the  acid  is  greater  in  proportion  to  the  loose- 
ness of  its  fibres,  the  effect  m.ust  necessarily  be  the  reverse  of  the  above.  However,  when 
it  is  required  to  produce  the  true  effect  of  the  printing  wood,  the  process  is  altered  as  fol- 
lows : — The  surface  upon  which  the  impression  is  to  be  taken  is  wetted  with  dilute  acid,  and 
an  impression  is  taken  with  the  veneering-wood  previously  wetted  with  diluted  ammonia  ; 
it  is  evident  that  in  this  case,  the  alkali  neutralizing  the  acid,  the  effect  resulting  from  the 
sub.sequcnt  action  of  heat  will  be  a  true  representation  of  the  printing  surface.  M.  Abate 
gives  this  variation  of  the  process  the  name  of  TuERMOcnAPiiY,  or  the  art  of  printing  by 
heat ;  but  this  term  has  been  already  applied  to  another  process. 

METALLURGY.  {Erzkunde,  Germ.)  The  art  of  extracting  metals  from  their  ores. 
Under  the  heads  of  the  different  metals  respectively,  the  metallurgical  processes  to  which 
thev  are  subjected  are  given  ;  still  there  are  a  few  general  details,  which  are  included  with  ad- 
Tan'tage  in  the  present  article.  A  full  description  ot  the  processes  of  preparing  the  minerals 
for  the  operations  of  the  metallurgist  will  be  found  under  the  head  of  Ores,  Dressing  of. 

Most  of  the  tin  ores  in  Cornwall  have  to  be  roasted,  or  calcined,  before  they  are  fit  for 
the  smelting-house,  although  in  some  mines  the  admixture  with  other  minerals  is  so  trifling, 
that  this  operation  is  considered  unnecessary.  The  furnace  {fifis.  420,  421)  in  which  the 
ro.asting  is  carried  on,  is  about  10  feet  long,  5  feet  0  inches  wide  in  the  middle,  and  3  feet 
wide  near  the  mouth.  The  fireplace,  it  will  be  observed,  is  situated  at  the  back,  the  flames 
playing  through  the  oven  and  ascending  the  chimney,  which  is  above  the  furnace  door. 
The  man  is  represented  in  /r/.  421  as  stirring  the  ore  with  a  long  iron  rake.  The  ore, 
before  it  is  submitted  to  theaction  of  the  fire,  is  thoroughly  dried  in  a  circular  pit,  placed 
immediately  above  the  oven,  into  which  it  is  let  down  through  the  opening  when  it  is  con- 
sidered to  be  ready  for  calcining.  Beneath  the  oven  and  connected  with  it  by  an  opening 
through  which  the  ore  when  sufficiently  roasted  is  made  to  p:i.«s,  is  an  arched  opening  about 
4  feet  wide,  termed  the  "  wrinkle."  Here  the  ore  >b  collected,  whilst  another  charge  is  being 
placed  in  the  furnace.     About  7  cwt.  or  8  cwt.  of  ore  is  the  quantity  usually  roasted  at  one 


METALLURGY. 


745 


time.     Whilst  undergoing  this  operation,  dense  fumes  of  arsenic  and  sulphur  escape  with 
the  smoke  from  the  fire,  and  pass  through  large  flues,  divided  into  several  chambers,  {fig. 


420 


422,)  where  the  former  is  collected.     The  flue  is  often  70  yards  long,  and  the  greatest  de- 
posit of  arsenic  takes  place  at  about  15  yards  from  the  oven  or  furnace.     Instead  of  being 


422 


at  once  completely  roasted,  the  "whits"  from  the  stamps  are  sometimes  first  "rag"  (or 
partially)  burnt,  for  al)out  six  or  eight  hours.     The  object  of  this  partial  burning  is  to  save 


746 


METALLUKGY. 


time  and  expense,  nearly  three-fourths  of  it  being  thrown  away  after  dressing  it  from  the 
first  burning. 

Fig.  423.     The  machine  called  originally  "Brunton's  Patent  Calciner,"  for  calcining  tin 

423 


ore,  is  gradually  coming  into  use  in  Cornwall,  ana  is  adopted  in  many  of  the  larger  mines. 
Its  operation  m'ay  be  thus  briefly  described  :— A  revolving  circular  tabic,  usually  8  feet,  or 
10  feet  in  diameter,  turned  by  a  water-wheel,  receives  through  the  hopper  the  tin  stuff  to 
be  roasted  or  calcined.  The  frame  of  the  table  is  made  of  cast-iron,  with  bands,  or  rings, 
of  wrought  iron,  on  which  rests  the  fire-bricks  composing  the  surface  of  the  table.  The 
flames  from  each  of  the  two  fireplaces  pass  over  the  ore  as  it  lies  on  the  table,  which  slowly 
revolves,  at  the  rate  of  about  once  in  every  quarter  of  an  hour.  In  the  top  of  the  dome, 
over  the  table,  are  fixed  three  cast-iron  frames  called  the  "  spider,"  from  which  depend  nu- 
merous iron  coulters,  or  teeth,  which  stir  up  the  tin  stuff,  as  it  is  carried  round  under  them. 
The  coulters  on  one  of  the  arms  of  the  "spider"  are  fixed  obliquely,  so  as  to  turn  the  ore 
downwards  from  one  to  the  other— the  last  one  at  the  circumference  of  the  table,  project- 
ing the  ore  (by  this  time  fully  calcined)  over  the  edge,  into  one  of  the  two  "  wrinkles  "  l)e- 
neath.  A  simple  apparatus  called  the  "  butterfly,"  moved  by  a  handle  outside  the  building, 
diverts  the  stream  of  roasted  tin  stuff,  as  it  falls  "from  the  table,  either  into  one  or  the  other, 


METER,  GAS.  747 

as  may  be  required.  Unlike  the  operation  of  roasting  in  the  oven  previously  described,  the 
calciner  requires  little  or  no  attention  ;  the  only  care  requisite  being  to  see  that  the  hopper 
is  fully  supplied,  and  the  roasted  ore  removed  when  necessary  from  the  wrinkles. 

For  this  description  of  the  burnin;^  house  and  of  the  calciner,  we  are  indebted  to  Mr. 
James  Henderson's  communication  to  the  Institution  of  Civil  Engineers. 

We  have  been  favored  with  the  following  notes  on  the  action  of  Brunton's  calciners, 
employed  at  Fabriea  la  Coustauto,  Spain,  which  are  of  great  value,  as  are  also  the  additional 
suggestions : — 

Diameter  of  revolving  bed,  14  feet. 

Revolution  of  bed  per  hour  from  3  to  4,  or  about  1  foot  of  the  circumference  per 
minute. 

Ores  introduced  by  hopper,  at  the  rate  of  1  quintal  to  every  revolution  of  table. 

Quantity  of  ore  calcined  per  day  of  10  hours,  30  to  35  quintals. 

Salt  consumed,  generally  6  per  cent,  of  weight  of  ore. 

Fuel  consumed  per  10  hours,  1,200  to  1,400  lbs.  of  pine  wood. 

Power  employed  to  revolve  table,  half  horse. 

Remarks. — The  furnace  is  charged  with  ore  and  salt  by  means  of  iron  hoppers  placed 
imruediately  over  the  centre  of  each  of  the  hearths.  For  the  supply  of  each  hopper,  a 
heap  of  about  14  quintals  of  ore,  with  5  or  6  per  cent,  of  salt,  is  prepared  from  time  to 
time  upon  a  small  platform  on  the  top  of  the  furnaces,  and  a  few  shovelfuls  thrown  in  occa- 
sionally as  required,  taking  care,  however,  always  to  have  enough  ore  in  the  hopper  to  pre- 
vent the  ascension  of  acid  vapors,  &c.,  from  the  furnace.  The  time  the  mineral  remains  in 
the  furnace,  and  the  quantity  calcined  per  hour,  must  depend  on  the  rapidity  of  motion  of 
the  revolving  hearth,  and  the  angle  at  which  the  iron  stirrers  are  fixed. 

The  average  amount  passed  through  each  furnace  in  24  hours  is  about  84  quintals,  or 
3i  quintals  per  hour.  For  every  revolution  of  the  bed,  nearly  1  quintal  is  discharged  I'rom 
the  furnace. 

Compared  with  the  German  Rostofen,  the  mechanical  furnaces  are  less  efficient  for  the 
calcination  of  silver  ores,  particularly  when  the  ores  operated  on  are  very  damp,  and  con- 
tain much  sulphur ;  in  which  case  the  excessive  production  of  lumps  becomes  a  serious  in- 
convenience to  contend  with. 

But  in  the  treatment  of  the  silver  ores  of  Steindelencira,  they  possess  the  advantage  of 
calcining  a  large  quantity  of  ore  in  a  given  time,  and  require  no  further  attendance  than  is 
necessary  for  supplying  them  with  ore  and  fuel.  The  supply  of  fuel  is,  however,  subject  to 
great  neglect.  Tiie  management  of  the  fires  is  nevertheless  a  matter  of  much  importance, 
for  should  they  be  forgotten,  and  the  heat  get  much  reduced,  the  mineral,  from  continuing 
to  pass  at  the  same  rate  through  the  furnace,  cannot  be  properly  calcined. 

To  prevent  the  fires  getting  low,  and  to  raise  them  after  being  neglected,  the  workmen 
often  load  the  grate  with  fuel,  tlie  result  of  which  is  to  overheat  the  ore  and  cause  a  great 
waste  of  wood. 

Some  measure  is  evidently  necessary  to  regulate  the  supply  of  fuel  to  the  grate. 

The  most  simple  appears  to  be  an  alarum  that  shall  be  rung,  for  example,  at  every  revo- 
lution of  the  hearth,  so  as  to  call  the  attention  of  the  men  to  tlie  fires  ;  and  then  not  more 
than  a  given  quantity  of  wood  should  be  thrown  on  the  grate,  which,  repeated  at  every 
turn  made  by  the  bed,  or  once  in  a  quarter  of  an  hour,  would  sustain  a  nearly  constant  tem- 
perature in  the  furnace.     See  Silver. 

METER,  GAS.  The  most  recently  constructed  meters  on  the  dry  principle  are  those 
of  Defries,  and  of  Messrs.  CroU  &  Richards.  Both  of  these  contrivances  consist  in  causing 
the  gas  to  fill  expansible  chambers  of  definite  volume,  and  the  alternate  expansion  and  con- 
traction of  these  is  registered  l)y  wheel-work. 

Defries'  meter  has  three  of  tiiese  measuring  chambers,  separated  from  each  other  by 
flexible  leather  partitions  which  are  partly  covered  by  metallic  plates,  to  protect  them  from 
the  action  of  the  gas.  a  a  a  a,  {fig.  424,)  represent  these  metallic  plates  fixed  upon  the 
leather  diaphragm  b  d  b  b.  As  the  gas  enters,  it  causes  the  flexible  partition  to  expand, 
which  it  does  by  a.ssuming  the  form  of  a  cone,  as  seen  in  fg.  425.  Three  such  chambers 
are  attached  to  each  meter,  so  as  to  insure  a  uniform  and  steady  supply  of  gas,  and  the 
motion  of  the  chambers  being  communicated  to  clockwork,  the  consumption  of  gas  is  regis- 
tered upon  dials  in  the  usual  manner. 

The  dry  meter  invented  by  Messrs.  Croll  &  Richards  is  superior  in  construction  and 
accuracy  of  measurement  to  that  of  Defries.  It  is  shown  in  figs.  42('),  427,  and  428.  a  a, 
{fig.  42t),)  is  a  cylindrical  case  divided  into  two  cylindrical  compartments  l)y  the  inflexible 
metallic  diaphragm  n.  These  compartments  are  closed  at  opposite  ends  by  the  metal  discs 
c  c.  The  latter  perform  the  functions  of  pistons,  and  arc  retained  in  their  proper  position 
by  universal  joints  attached  to  each.  The  discs  are  restrained  from  moving  through  more 
than  a  fixed  space  by  metalHc  arms  and  rods,  shown  in  fig.  427,  and  wlien  this  .«;pace  has 
been  once  adjusted  it  cannot  afterwards  vary.  It  will  be  seen  that  the  principle  of  this 
meter  is  that  of  a  piston  moving  in  a  cylinder ;  but,  in  order  to  avoid  the  friction  which 


748 


METER,  GAS. 


such  an  arrangement  would  cause  if  literally  carried  out,  bands  of  leather,  d  d,  are  attached, 
which  act  as  hinges,  and  allow  of  the  motion  of  the  discs  without  friction. 


424 


425 


The  gas  enters  the  cylinder  from  the  upper  space  containing  the  levers,  valves,  &c.,  {jig. 
428  ;)  its  pressure  forces  the  discs  forward  through  the  space  limited,  as  above  described. 


METKA. 


749 


The  flow  of  gas  is  then  reversed ;  that  is,  a  passage  to  the  bumere  is  opened  from  the  inter- 
nal space,  whilst  the  supply  is  now  directed  into  the  outer  chamber,  thus  forcing  the  disc 
back  to  its  original  position  and  expelling  the  first  portion  of  gas  through  the  pipes  of  dis- 
tribution. Each  motion  of  the  disc  thus  evidently  corresponds  to  a  given  volume  of  gas, 
and,  being  registered  by  clockwork,  indicates  the  consumption  upon  the  usual  dial  plates. 

Dry  gas-meters  have  of  late  years  come  into  vei-y  extensive  use,  especially  in  the  me- 
tropolis.— E.  F. 

METRA.  This  pocket  instrument,  constructed  by  the  late  Mr.  Herbert  Mackworth — 
one  of  H.  M.  Inspectors  of  Collieries, — enables  the  traveller  or  engineer  to  take,  with  con- 
siderable accuracy,  most  of  those  measurements  which  it  is  useful  to  record,  and  to  make 
use  of  opportunities  which  would  otherwise  be  lost.  In  a  brass  case,  less  than  three  inches 
square  and  an  inch  thick,  are  contained  a  clinometer,  thermometer,  goniometer,  level,  mag- 
nifying lens,  measure  for  wire  gauze,  plummet,  platina  scales  of  various  kinds,  and  an  ane- 
mometer. Tiie  traveller  can  ascertain  by  its  means  the  temperature,  the  force  of  the  wind, 
the  latitude,  the  position  of  the  rocks,  or  survey  and  map  his  route.  The  geologist  can  de- 
termine and  draw  the  direction  and  amount  of  dip  of  the  rocks,  the  angles  of  cleavage  and 
crystallization,  the  temperature  of  springs,  or  examine  by  a  plate  of  tourmaline  the  bottoms 
of  pools  or  shallow  depths  along  coast  lines  otherwise  invisible  to  the  eye.  The  miner  can 
survey  and  level  the  roof  or  floor  of  his  workings,  and  requires  only  a  pencil  to  map  them 
upon  paper.  He  can  ascertain  the  temperature  of  the  air  under  ground,  discover  whether 
the  ventilation  is  deficient,  or  see  whether  the  wires  of  his  Davy  lamp  are  in  safe  condition. 

Figs.  429,  430  represent  the  plan  and  side  view  of  the  "metra"  when  open  and  ready 
for  use.     A  is  the  double  compass,  and  b  the  level.     The  arc  of  the  level  is  graduated  in 


429 


degrees,  and  in  inches  fall  per  yard,  c  the  sights  ;  d  the  scales ;  e  the  goniometer ;  e'  the 
goniometer  scale  ;  f  the  plummet ;  g  the  lens,  witli  a  telesc()!)ic  slide  underneath  to  meas- 
ure wire  gauze  ;  ii  the  tourmaline  ;  j  the  pivots  on  which  the  instrument  stands  ;  k  are  the 
two  joints  of  the  brass  leg,  by  which  the  horizontality  of  the  instrument  can  be  obtained  ; 


750  MINERAL  CANDLES. 

L  is  a  flai  chisel  point  for  entering  joints  of  rocks  or  masonry.  This  end  unscrews,  expos- 
ing a  wood-screw,  (shown  by  the  dotted  lines  m,)  by  which  the  leg  can  be  secured  to  a  tree 
or  stand  ;  N  is  the  tliermometer,  which,  like  the  compass  and  level,  will  read  correctly  to 
half  a  degree  ;  o  is  the  screw  which  holds  the  top  and  bottom  of  the  instrument  together 
when  they  are  opened  out  for  use,  as  in  the  drawing.  Beneath  the  bottom  cover  p  are 
placed  the  anemometer,  which  consists  of  a  thin  sheet  of  transparent  mica  suspended  by 
pieces  of  silk,  and  underneath  the  mica  is  a  table  of  "  constants,'  giving  the  weights  of 
gases,  liquids,  and  solids,  besides  some  thirty  measures  .and  formulae  for  steam,  boilers,  en- 
gines, ropes,  air,  &c.  The  brass  leg  is  seldom  of  use,  and  may  be  dispensed  with.  By 
resting  the  under  edge  of  the  side  e  k'  on  a  bed  of  rock,  and  turning  the  instrument  till  the 
bubble  comes  in  the  middle  of  the  level,  the  direction  of  the  "  strike  "  or  "  level  course  " 
of  the  rock  will  be  ascertained  instrumentally.  k  e'  ofiers  a  long  line  to  measure  the 
amount  of  inclination  with.  To  lay  down  surveys  on  paper,  a  line  should  be  ruled,  and  the 
edge  E  e'  liiid  to  it.  The  paper  should  then  be  moved  until  the  ruled  line  comes  exactly 
north  and  south,  when  it  can  be  weighted  down.  The  survey  is  then  made  by  the  compass, 
and  the  ecales  on  the  paper,  just  as  it  had  been  made  on  the  ground,  without  the  usual  cal- 
culation and  ruling  of  parallel  lines.  A  simpler  form  is  made  in  wood  as  a  clinometer,  con- 
taining only  the  compass,  level,  magnifying  glass,  and  thermometer  for  the  use  of  geolo- 
gists. 

MINERAL  CANDLES.  These  candles  and  other  products  (liquid  hydro-carbons)  are 
manufactured  by  Price's  Candle  Company,  at  Belmont  and  Sherwood,  according  to  processes 
patented  by  Mr.  Warren  De  la  Rue.  The  novelty  of  these  substances  consists — 1.  In  the 
material  from  which  they  are  obtained.  2.  In  the  method  by  which  they  are  elaborated. 
3.  In  their  chemical  constitution. 

The  rail]  material  is  a  semi-fluid  naphtha,  drawn  up  from  wells  sunk  in  the  neighborhood 
of  the  river  Irrawaddy,  in  the  Burmese  empire.  The  geological  characteristics  of  the  local- 
ity are  sandstone  and  blue  clay.  In  its  raw  condition  the  substance  is  used  by  the  natives 
as  a  lamp-fuel,  as  a  preservative  of  timber  against  insects,  and  as  a  medicine.  Being  in 
part  volatile  at  common  temperatures,  this  naphtha  is  imported  in  hermetically  closed  metal- 
lic tanks,  to  prevent  the  loss  of  any  constituent.  Reichenbach,  Christison,  Gregory,  Reece, 
Young,  Wiesman,  (of  Bonn,)  and  others,  have  obtained  from  peat,  coal,  and  other  organic 
minerals,  solids  and  liquids  bearing  some  physical  resemblance  to  those  procured  from  the 
Burmese  naphtha ;  but  the  first-named  products  have,  in  every  instance,  been  formed  by 
the  decomposition  of  th<!  raw  material.  The  process  of  De  la  Rue  is,  from  first  to  last,  a 
simple  separation,  without  chemical  change. 

In  the  commercial  processes,  as  carried  out  at  the  Sherwood  and  Belmont  Works,  the 
crude  naphtha  is  first  distilled  with  steam  at  a  temperature  of  212^  F.  ;  about  one-fourth  is 
separated  by  this  operation.  The  distillate  consists  of  a  mixture  of  many  volatile  hydro- 
carbons ;  and  it  is  extremely  difficult  to  separate  them  from  each  other  on  account  of  their 
vapors  being  mutually  very  diffusible,  however  different  may  be  their  boiling  points.  In 
practice,  recourse  is  had  to  a  second  or  third  distillation,  the  products  of  which  are  classi- 
fied according  to  their  boiling  points  or  their  specific  gravities,  which  range  from  '627  to 
•8<30,  the  lightest  coming  over  first.  It  is  worthy  of  notice,  that  though  all  these  volatile 
liquids  were  distilled  from  the  original  material  with  steam  of  the  temperature  of  boiling 
water,  their  boiling  points  range  from  80°  Fahr.  to  upwards  of  400°  Fahr. 

Those  liquids  are  all  colorless,  and  do  not  solidify  at  any  temperature,  however  low,  to 
which  they  have  been  exposed.  They  are  useful  for  many  purposes.  All  are  solvents  of 
caoutchouc.  The  vapor  of  the  more  volatile  Dr.  Snow  has  found  to  be  highly  anaesthetic. 
Those  which  are  of  lower  specific  gravity  are  called  in  commerce  Shcrivoodolc  and  Bcbnon- 
tine ;  these  have  great  detergent  power,  readily  rcmovirg  oily  stains  from  silk,  without  im- 
pairing even  delicate  colors.  The  distillate  of  the  higher  specific  gravity  is  proposed  to  be 
used  as  lamp-fuel ;  it  burns  with  a  brilliant  white  flame,  and,  as  it  cannot  be  ignited  without 
a  wick,  even  when  heated  to  the  temperature  of  boiling  water,  it  is  safe  for  domestic  use. 

A  small  percentage  of  hydro-carbons,  of  the  lienzolc  series,  comes  over  with  the  distil- 
lates in  this  first  operation.  Messrs.  De  la  Rue  and  Miiiler  have  shown  that  it  may  be  ad- 
vantageously eliminated  Ijy  nitric  acid.  The  resulting  substances,  nitro-benzole,  &c.,  are 
commercially  valualilc  in  perfumery,  &c. 

After  steam  of  212°  has  been  used  in  the  distillation  just  described,  there  is  left  a  resi- 
due, amounting  to  about  three-fourths  of  the  original  material.  It  is  fused  and  purified 
from  extraneous  ingredients  (which  Warren  Do  la  Rue  and  II.  Miiiler  have  found  to  consist 
partly  of  the  coloplicnc  series)  by  sulphuric  acid.  The  foreign  substances  are  thus  thrown 
down  as  a  black  precipitate,  from  which  the  supernatant  liquor  is  decanted.  The  black  pre- 
cipitate, when  freed  from  acid  by  copious  washing,  has  all  the  characteristic  properties  of 
native  asphaltum.  The  fluid  is  then  transferred  to  a  still,  and,  by  means  of  a  current  of 
steam  made  to  pass  through  heated  iron  tubes,  is  distilled  at  any  required  temperature. 
The  distillates  obtained  by  this  process  arc  classed  according  to  their  distilling  points,  rang- 
ing from  :iOO"  to  G00°  Fahr.     The  distillations  obtained,  at  430°  Fahr.  and  upwards,  con- 


MINES  OF  NORTH  AMERICA. 


751 


tain  a  solid  substance,  resembling  in  color  and  in  many  physical  and  chemical  properties 
the  paraffine  of  Reichenbaeh  ;  like  it,  it  is  electric,  and  its  chemical  affinity  is  very  feeble  : 
but  there  are  reasons  for  believing  that  a  difference  exists  in  the  atomic  constitution  of  the 
two  substances.  The  commercial  name  of  Belmontine  is  given  to  one  of  the  fluids  from 
the  Burmese  pitch.  Candles  manufactured  from  the  soild  material  (Paraffine)  possess  great 
illuminating  power.  It  is  stated  that  such  a  candle,  weighing  '/»  lb.,  will  give  as  much  light 
as  a  candle  weighing  Vo  lb.  made  of  spermaceti  or  of  stearic  acid.  Its  property  of  fusing 
at  a  very  low  temperature  into  a  transparent  liquid,  and  not  decomposing  below  600"  Fahr., 
recommends  this  substance  as  the  material  of  a  bath  for  chemical  purposes.  As  to  the 
fluids  obtained  in  the  second  distillation,  already  described,  they  all  possess  great  lubricating 
properties ;  and,  unlike  the  common  fixed  oils,  not  being  decomposable  into  an  acid,  tliey 
do  not  corrode  the  metals,  especially  the  alloys  of  copper,  which  are  used  as  bearings  of 
machinery.  This  aversion  to  chemical  combination,  which  characterizes  all  these  substances, 
affords  not  only  a  security  against  the  brass-work  of  lamps  being  injured  by  the  hydro-car- 
bon burnt  in  them,  but  also  renders  these  hydro-carbons  the  best  detergents  of  common  oil 
lamps.  It  is  an  interesting  physical  fact,  tliat  some  of  the  non-volatile  liquid  hydro-carbons 
possess  the  fluorescent  property  which  Stokes  has  found  to  reside  in  certain  vegetable  infu- 
sions. 

An  important  characteristic  of  the  Burmese  naphtlia  is  its  being  almost  enth'ely  desti- 
tute of  the  hydro-carbons  belonging  to  the  olefiant  gas  series.     See  Naphtha. 

MINES  OF  NORTH  AMERICA.  Within  the  last  few  years  a  stupendous  activity  in  the 
production  of  certain  metals  has  succeeded  to  the  unimportant  trials  which  at  intervals  used 
to  be  made  in  the  earlier  part  of  this  century.  It  is  especially  the  discovery  of  gold  in 
California  in  1848,  which  has  invited  the  attention  of  the  world  to  the  metallic  riches  of  the 
Pacific  side  of  this  continent,  or  to  the  western  flank  of  the  continuation  of  the  great  chain 
of  motuitains  which  we  have  traced  upwards  from  South  America. 

Almost  the  entire  quantity  of  the  gold  produced  in  California  is  obtained  from  stream- 
works,  washings,  or  "diggings,"  but  the  precious  metal  itself  has  evidently  been  derived 
from  the  granitic  and  the  ancient  slaty  rocks  which  constitute  the  range  of  the  Sierra  Nevada. 
Numerous  vefns,  consisting  principally  of  quartz,  have  been  proved  to  be  auriferous,  ))ut 
although  large  companies,  mostly  English,  have  been  organized  for  working  them,  little 
success  has  yet  attended  their  efforts.  Platinum  and  osmiridium  have  also  been  found  here, 
thus  establishing  an  analogy  with  the  Brazilian  localities. 

The  auriferous  tract  extends  northward  far  into  the  British  territory. 

In  one  of  the  side  valleys  of  San  Jose,  a  mine  of  quicksilver,  "  New  Almaden,"  has  for 
some  years  been  opened  upon  irregular  and  contorted  deposits  of  cinnabar,  associated  with 
clay  slates  highly  inclined  and  similarly  contorted.  It  is  said  that  above  10,000  cwts.  of 
mercury  are  produced  here  annually. 

On  the  eastern  or  Atlantic  side  of  the  North  American  continent,  the  existence  of  gold 
has  long  been  known,  as  well  in  alluvium  in  Virginia,  Carolina,  Georgia,  and  Canada,  as  in 
veins  which  occur  at  intervals  in  the  schist  rocks  of  the  Appalachian  chain,  and  which  have 
given  rise  to  numerous  explorations. 

The  veins  appear  generally  to  course  N.N.E.  and  S.S.  W.  and  to  consist  mainly  of  quartz, 
often  extending  to  a  great  thickness.  Few,  however,  of  these  mines  have  been  followed 
down  to  a  depth  of  more  than  100  feet,  or  have  been  developed  on  a  continuously  large 
scale. 

Lead  mines  have  been  worked  in  distinct  veins  at  Rossie,  St.  Lawrence  County,  N.  Y., 
at  Shelburne  in  New  Hampshire,  Southampton  and  Northampton,  in  Massachusetts, 
Middletown,  Connecticut,  Chester  County,  and  Wheatley  mines,  Pennsylvania;  but  the  most 
important  are  those  opened  in  irregular  deposits  sometimes  vertical,  at  others  horizontal, 
wliich  distinguish  the  Silurian  limestones  of  the  Upper  Mississippi.  The  lead-bearing  region 
is  87  miles  long  from  east  to  west,  and  54  miles  broad  from  north  to  .south,  the  chief 
centres  being  Galena,  Mineral  Point,  and  Dubuque.  The  ore,  generally  pure  galena, 
occurs  with  great  irregularity,  and  thus  leads  to  the  expenditure  of  large  sums  in  "])i().s- 
pecting"  of  a  very  s[)ecul;itive  character.  It  occupies  only  one  zone,  about  100  feet  in 
tiiickne.ss,  of  the  "galena"  limestone,  and  hence  the  mines  have  been  but  shallow,  and  the 
production  is  on  the  decline,  liaving  tlwindled  from  '24,300  tons  of  lead  in  1845,  to  lo,o(iO 
in  1853.  In  Missouri  an  analogous  state  of  things  occurs,  but  on  a  smaller  scale.  Copper 
lias  been  worked  at  .several  mines  in  the  Atlantic  States,  at  Biistol,  Connecticut ;  Sykesville, 
&c.,  in  Maryland  ;  Schuyler,  and  other  mines,  New  Jersey  ;  several  newly  opened  localities 
in  Tennessee  ;  and  Perkiomen  in  Penn.sylvania,  where  tlie  veins  occur  in  new  red  sandstone 
and  .shale. 

In  1841  the  publication  of  Mr.  Doughton,  State  geologist  for  Michigan,  first  drew  public 
attention  to  the  native  copper  of  Lake  Superior,  which  since  1844  has  been  the  object  of 
very  numerous  workings,  and  has  been  produced  in  steadily  increasing  quantity  uj)  to 
5,000  tons  per  annum. 

The  veins  here  occur  in  a  district  of  bedded  augitic  greenstone,  amygdaloid,  and  sand- 


Y52  MINING. 

stone,  with  conglomerate  of  the  lower  Silurian  period,  and  are  especially  remarkable  for 
bearing  native  copper  without  any  of  the  ordinary  ores  of  that  metal. 

Ores  of  zinc  are  associated  with  lead  ores  at  several  of  the  above-mentioned  localities, 
especially  in  the  Wisconsin  district,  where  the  calamine  is  known  among  the  miners  by  the 
name  of  "dry -bone."  But  one  of  the  most  peculiar  mineral  deposits  in  the  United  States 
is  that  of  the  red  oxide  of  zinc,  and  of  Franklinite,  which  occur  in  Sussex  County,  New  Jer- 
sey, at  Sparta  and  Stirling.  They  are  intercalated  among  the  beds  of  a  crystalline  limestone, 
with  a  total  thickness  of  above  30  feet,  and  are  the  scene  of  very  successful  undertakings. 

Lastly,  iron  ores  of  various  species,  particularly  the  magnetic  oxide  and  haematite,  occur 
in  numerous  localities.  Missouri  is  remarkable  for  large  masses  which  are  said  to  have  an 
eruptive  character,  and  Lake  Superior  offers  even  a  greater  abundance. 

A  bed  of  black  oxide  of  iron  occurs  in  gneiss  near  Francouia  in  New  Hampshire.  It 
has  a  width  of  from  5  to  8  feet ;  and  has  been  mined  through  a  Icngtli  of  200  feet,  and  to  a 
depth  of  90  feet.  The  same  ore  is  found  in  veins  in  Massachusetts  and  Vermont,  ac- 
companied by  copper  and  iron  pyrites.  It  is  met  with  in  immense  quantities  on  the 
western  bank  of  Lake  Champlain,  forming  beds  of  from  1  to  20  feet  in  thickness,  almost 
without  mixture,  encased  in  granite.  It  is  also  found  in  the  mountains  of  that  territory. 
These  deposits  appear  to  extend  without  interruption  from  Canada  to  the  neighborhood 
of  New  York,  where  an  exploration  on  them  may  be  seen  at  Crown-Point.  The  ore  there 
extracted  is  in  much  esteem.  Several  mines  of  the  same  species  exist,  in  New  Jersey.  The 
primary  mountains  which  rise  in  the  north  of  this  State  near  the  Delaware,  include  beds 
almost  vertical  of  black  oxide  of  iron,  which  have  been  worked  to  100  feet  in  depth.  In 
the  county  of  Sussex  the  same  ore  occurs,  accompanied  with  Franklinite.  At  Roxbury,  in 
Connecticut,  a  good  sized  lode  of  sparry  iron  occurs ;  the  only  one  of  the  kind  known  in 
the  Alleghanies.  The  United  States  contain  a  great  many  iron  works,  some  of  which  prior 
to  the  year  1773  sent  over  iron  to  London.  Those  in  Connecticut,  Massachusetts,  and  New 
York,  have  been  largely  supplied  with  iron  ores  of  the  tertiary  formation,  whilst  those  of 
Virginia  and  Maryland  employ  on  an  extensive  scale  coal  measure  ironstone. 

Before  quitting  America,  it  should  be  mentioned  that  the  West  India  Islands  offer  nu- 
merous indications  of  mineral.  Many  cupriferous  veins  have  been  explored  on  a  small  scale 
in  Jamaica.  Copper  ore  and  molybdenite  occur  at  Virgin  Gorda,  and  Cuba  has  for  many 
years  past  been  remarkable  for  the  richness  and  abundance  of  its  copper  ores.  The  principal 
mine  is  the  Cobre,  an  adventure  worked  on  an  extensive  scale,  and  very  remunerative  to 
its  proprietary.  The  lodes,  which  have  been  very  large  at  shallow  depths,  course  E.  and 
W.  through  greenstone  and  conglomeritio  rock.  The  Santiago  mines  have  also  yielded  a 
large  amount  of  ore. 

MIXING.  As  the  operations  of  mining  vary  with  the  conditions  of  the  rock  formations, 
in  which  the  minerals  sought  for  by  the  miner  occur,  it  is  necessary  to  give  a  brief  de- 
scription of  the  more  especially  marked  distinctions  which  are  seen  in  our  geological 
formations. 

Geologists  divide  rocks  into  stratified  and  unstratificd.  Those  mineral  systems  which 
consi.st  of  parallel,  or  nearly  parallel  planes,  whose  length  and  breadth  greatly  exceed  their 
thickness,  are  called  stratified  rocks ;  while  to  those  which  occur  in  thick  blocks,  and  which 
do  not  exhibit  those  parallel  planes,  the  term  of  unstratificd  rocks  is  applied.  These 
formations  have  been  divided  into  two  other  classes,  namely  the  primary  and  the  secondary. 
The  advances  of  geological  science,  however,  and  more  accurate  information,  have  materi- 
ally modified  the  views  which  gave  rise  to  those  divisions  ;  and  when  men  have  learned  to 
look  on  great  natural  phenomena  without  the  interposition  of  the  medium  of  some  favorite 
theory,  there  is  but  little  doubt  the  interpretation  will  be  somewhat  difterent  from  even  that 
which  is  now  received. 

A  certain  set  of  rocks  may  be  classed  as  of  truly  igneous  origin.  These  are  the  traps, 
basalts,  and  the  like.  These  have  often  been  termed  primary  rocks.  Yet  we  have  rocks 
of  this  class,  not  merely  forcing  their  way  through  the  superincumbent  and  more  recent 
rocks,  but  actually  overflowing  them  :  they  may,  therefore,  be  much  more  recent  than  the 
secondary  rocks.  Granite  has  commonly  been  classed  as  a  truly  igneous  rock ;  but  facts 
liave  lately  been  developed  which  show,  at  all  events,  the  combined  action  of  water,  and  the 
probability  appears  to  be  that  granite,  gneiss,  and  elvans  have  been  formed  under  highly 
heated  water. 

Granite  is  usually  classed  with  the  unstratificd  rocks ;  but  the  section  of  any  granite 
quarry  will  exhibit  very  distinct  lines,  conforming,  more  or  less,  to  the  horizontal — known 
to  the  quarrymen  as  the  bcdicay — which  would  appear  sullicicnt  to  place  those  rocks 
amongst  the  stratified  ones. 

It  is  commonly  stated  that  the  unstratificd  rocks  possess  a  nearly  vertical  position,  the 
stratified  rocks  assuming  more  nearly  a  horizontal  one.  There  are  numerous  examples 
adverse  to  this  view ;  indeed,  it  must  be  regarded  as  a  hasty  generalization — the  bedway  of 
the  granite  approaching  very  nearly  to  the  horizontal,  while  we  often  find  the  truly  stratified 
rocks  in  a  vertical  position. 


MINING.  753 

Where  the  older  rocks  graduate  down  into  the  plains,  rocks  of  an  intermediate  character 
appear,  which,  though  possessing  a  nearly  vertical  position,  like  the  unstratified  and  non- 
fossiliferous  rocks,  contain  a  few  vestiges  of  animal  beings,  especially  shells.  These  have 
been  called  transition,  to  indicate  their  being  the  passing  links  between  the  first  and  second 
systems  of  ancient  deposits ;  they  are  distinguished  by  the  fractured  and  cemented  texture 
of  their  planes,  for  which  reason  they  are  sometimes  called  conglomerate. 

Between  the  older  and  the  secondary  rocks,  another  very  valuable  series  is  interposed 
in  certain  districts  of  the  globe  ;  namely,  the  coal-measures,  the  paramount  formation  of 
Great  Britian.  The  coal  strata  are  frequently  disposed  in  a  basin-forrn,  and  alternate  with 
parallel  beds  of  sandstone,  slate-clay,  iron-stone,  and  occasionally  of  limestone. 

As  a  practical  rule  it  may  be  here  stated,  that  in  every  mineral  formation,  the  inclination 
and  direction  are  to  be  noted  ;  the  former  being  the  angle  which  it  forms  with  the  horizon,  the 
latter  the  point  of  the  azhnuth  or  horizon,  towards  which  it  dips,  as  west,  northeast,  south, 
&c.  The  direction  of  a  bed  is  that  of  a  horizontal  line  diawn  m  its  plane  ;  and  which  is  also 
denoted  by  the  point  of  the  compass.  Since  the  lines  of  direction  and  inclination  are  at 
right  angles  to  each  other,  the  first  may  always  be  inferred  from  the  second  ;  for  when  a 
stratum  is  said  to  dip  to  the  east  or  west,  this  implies  that  its  direction  is  north  and  south. 

The  following  terms  have  been  used  to  express  dissimilar  conditions  in  mineral  deposits, 
well  known  to  the  practical  miner. 

Masses  are  mineral  deposits,  not  extensively  spread  in  parallel  planes,  but  irregular 
heaps,  rounded,  oval,  or  angular,  enveloped  in  whole  or  in  a  great  measure  by  rocks  of  a 
ditterent  kind.  Lenticular  masses  being  frequently  placed  between  two  horizontal  or  in- 
clined strata,  have  been  sometimes  supposed  to  be  stratiform  themselves,  and  have  been 
accordingly  denominated  by  the  Germans  liegcnde  stocke,  lying  heaps  or  blocks. 

The  orbicular  masses  often  occur  in  the  interior  of  unstratified  mountains,  or  in  the 
bosom  of  one  bed.  These  frequently  indicate  preexisting  cavernous  spaces,  which  have 
been  filled  in  with  metalliferous  or  mineral  matter. 

Nests,  concretions,  uodulcs,  are  small  masses  found  in  the  middle  of  strata ;  the  first 
being  commonly  in  a  friable  state ;  the  second  often  kidney-shaped,  or  tuberous ;  the  third 
nearly  round,  and  encrusted,  like  the  kernel  of  an  almond. 

Lodes,  or  veins,  are  flattened  masses,  with  their  opposite  surfaces  not  always  parallel. 
These  sometimes  terminate  like  a  wedge,  at  a  greater  or  less  distance,  and  do  not  run 
parallel  with  the  rocky  strata  in  which  they  lie,  but  cross  them  in  a  direction  not  far  from 
the  perpendicular ;  often  traversing  several  different  mineral  planes.  The  lodes  are  some- 
times deranged  in  their  course,  so  as  to  pursue  for  a  little  way  the  space  between  two  con- 
tiguous strata  ;  at  other  times  they  divide  into  several  branches.  The  matter  which  fills 
the  lodes  is  for  the  most  part  entirely  different  from  the  rocks  they  pass  through,  or  at  least 
it  possesses  peculiar  features. 

This  mode  of  occurrence  suggests  the  idea  of  clefts  or  rents  having  been  made  in  the 
stratum  posterior  to  its  consolidation,  and  of  the  vacuities  having  been  filled  witli  foreign 
matter,  either  immediately  or  after  a  certain  interval.  There  can  be  no  doubt  as  to  the 
justness  of  the  first  part  of  the  proposition,  for  there  may  be  observed  round  many  lodes 
undeniable  proofs  of  the  movement  or  dislocation  of  the  rock ;  for  example,  upon  each  side 
of  the  rent  the  same  strata  are  no  longer  situated  in  the  same  plane  as  before,  but  make 
greater  or  smaller  angles  with  it ;  or  the  stratum  upon  one  side  of  the  lode  is  raised  con- 
siderably above,  or  depressed  considerably  below,  its  counterpart  upon  the  other  side. 
With  regard  to  the  manner  in  which  the  rent  has  been  filled,  different  opinions  may  be 
entertained.  In  the  lodes  which  are  widest  near  the  surface  of  the  ground,  and  graduate 
into-a  thin  wedge  below,  the  foreign  matter  would  seem  to  have  been  introduced  as  into  a 
funnel  at  the  top,  and  to  have  carried  along  with  it  portions  of  rounded  gravel  and  sometimes, 
though  rarely,  organic  remains.  In  other,  but  very  exceptional  cases,  lodes  are  largest  at 
their  under  part,  and  become  progressively  narrower  as  they  ajiproach  the  surface  ;  from 
this  circumstance,  it  has  been  inferred  that  the  rent  has  been  caused  by  an  expansive  force 
acting  from  within  the  earth,  and  that  the  foreign  matter,  having  been  in  a  fluid  state,  has 
afterwards  slowly  crystallized.  Accurate  observation  shows  that  in  the  large  majority  of 
cases  the  metalliferous  dejjosits  are  of  aqueous,  and  not  of  igneous  origin. 

In  the  lodes,  the  principal  mattei-s  which  fill  them  are  to  be  distinguished  from  the  ac- 
cessory substances;  the  latter  being  distributed  irregularly,  amidst  the  mass  uf  the  first,  in 
crystals,  nodules,  grains,  seams,  &c.  The  non-metalliferous  portion,  which  is  often  the 
largest,  is  called  gnngiic,  from  the  (Jerman  gang,  vein.  The  position  of  a  vein  is  denoted, 
like  that  of  the  stratum,  by  the  angle  of  inclination,  and  the  point  of  the  horizon  towards 
which  it  dips,  whence  the  direction  is  deduced.  In  jioiiular  lan<;uage  a  lode  may  be  de- 
scribed to  be  a  crack  or  fissure,  such  as  is  formed  in  the  drying  of  a  i)asty  mass,  extending 
over  a  considerable  extent  of  country,  and  penetrating  to  a  great  depth  into  the  earth. 

A  metalliferous  substance  is  said  to  be  disseminutcd,  when  it  is   dispersed   in  crystals, 
spangles,  scales,  globules,  &c.,   through  a  large  mineral  mass.     Tin  is  not  unfrequently 
thus  disseminated  through  granite  and  clay-slate  rocks. 
Vol.  III.— 48 


754  MINING. 

Certain  ores  which  contain  the  metals  most  indispensable  to  human  necessities,  have 
been  treasured  up  by  the  Creator  in  very  bountiful  deposits;  constituting  either  great  masses 
in  rocks  of  different  kinds,  or  distributed  in  lodes,  veins,  nests,  concretions,  or  beds,  with 
stony  and  earthy  admixtures  ;  the  whole  of  which  become  the  objects  of  mineral  exploration. 
These  stores  occur  in  different  stages  of  the  geological  formations;  but  their  main  portion, 
after  having  existed  abundantly  in  the  several  orders  of  the  older  strata,  cease  to  be  found 
towards  the  middle  of  the  secondary  rocks.  Iron  ores  are,  with  a  few  exceptional  cases, 
the  only  ones  which  continue  among  the  more  modern  deposits,  even  so  high  as  the  beds 
immediately  beneath  the  chalk,  when  they  exist  almost  entirely  as  coloring  matters  of  the 
tei-tiary  beds. 

Granite,  gneiss,  mica,  and  clay-slate  constitute  in  Europe  the  grand  metallic  domain. 
There  is  hardly  any  kind  of  ore  which  does  not  occur  in  these  in  sufficient  abundance  to 
become  the  object  of  mining  operations,  and  many  are  found  in  no  other  rocks.  The  transi- 
tion rocks  and  the  lower  part  of  the  secondary  ones,  are  not  so  rich,  neither  do  they  contain 
the  same  variety  of  ores.  But  this  order  of  things,  which  is  presented  by  Great  Britain, 
Germany,  France,  Sweden,  and  Norway,  is  far  from  forming  a  general  law  ;  since  in  equi- 
noctial America  the  gneiss  is  but  little  metalliferous ;  while  the  superior  strata,  such  as  the 
clay-schists,  the  sienitic  porphyries,  the  limestones,  which  complete  the  transition  series,  as 
also  several  secondary  deposits,  include  the  greater  portion  of  the  immense  mineral  wealth 
of  that  region  of  the  globe. 

All  the  substances  of  wliich  the  ordinary  metals  form  the  basis,  are  not  equally  abundant 
in  nature;  a  great  proportion  of  the  numerous  mineral  species  which  figure  in  our  classifi- 
cations, are  mere  varieties  scattered  up  and  down  in  the  cavities  of  the  great  masses  or 
lodes.  The  workable  ores  are  few  in  nmnber,  being  mostly  sulphides,  oxides,  and  carbon- 
ates. These  occasionally  form  of  themselves  very  large  masses,  but  more  frequently  they 
are  blsnded  with  lumps  of  quartz,  felspar,  and  carbonate  of  lime,  which  form  the  main 
body  of  the  deposit.  The  ores  in  that  case  are  arranged  in  small  layers  parallel  to  the  strata, 
or  in  small  veins  which  traverse  the  rock  in  all  directions,  or  in  nests,  or  concretions  station- 
ed irregularly,  or  finally  disseminated  in  hardly  visible  particles.  These  deposits  sometimes 
contain  only  one  species  of  ore,  sometimes  several,  which  must  be  mined  together,  as  they 
seem  to  be  of  contemporaneous  formation :  whilst,  in  other  cases,  they  are  separable,  hav- 
ing been  probably  formed  at  different  epochs. 

Mineral  Veins. — In  different  districts  in  this  country  the  terms  used  to  distinguish  min- 
eral veins  vary  considerabh'.  The  following  terms  prevail  in  Derbyshire  and- the  north  of 
England:  — 

Lodes  or  mineral  veins  are  usually  distinguished  by  the  miners  of  these  districts  into  at 
least  four  species  : — 1.  The  rake  vein.  2.  The  pipe  vein.  3.  The  flat  or  dilated  vein  ;  and 
4.  The  interlaced  mass,  (xlock-u-erke,)  indicating  the  union  of  a  multitude  of  small  veins 
mixed  in  every  possible  direction  with  each  other,  and  with  the  rock. 

1.  The  rake  vein  is  a  mineral  fissure,  and  is  the  form  best  known  among  practical 
miners.  It  commonly  runs  in  a  straight  line,  beginning  at  the  superficies  of  the  strata,  and 
cutting  them  downwards,  generally  further  than  can  be  reached.  This  vein  sometimes 
stands  quite  perpendicular  ;  but  it  more  usually  inclines  or  hangs  over  at  a  greater  or  smaller 
angle,  or  slope,  which  is  called  by  the  miners  the  hade  or  hadiv(j  of  the  vein.  The  line  of 
direction  in  which  tlie  fissure  runs,  is  called  the  bearinc/  of  the  vein. 

2.  The  pipe  vein  resembles  in  many  respects  a  huge  irregular  cavern,  pushing  forward 
into  the  body  of  the  earth  in  a  sloping  direction,  under  various  inclinations,  from  an  angle 
of  a  few  degrees  to  the  horizon,  to  a  dip  of  45°,  or  more.  The  pipe  does  not  in  general 
cut  the  strata  across  like  the  rake  vein,  but  insinuates  itself  between  them  ;  so  that  if  the 
plane  of  the  strata  be  nearly  horizontal,  the  bearing  of  the  pipe  vein  will  be  conformable ; 
but  if  the  strata  stand  up  at  a  high  angle,  the  pipe  shoots  down  nearly  headlong  like  a  shaft. 
Some  pipes  are  very  wide  and  high,  others  are  very  low  and  narrow,  sometimes  not  larger 
than  a  common  mine  or  drift. 

3.  The  flat  or  dilated  vein,  is  a  space  or  opening  between  two  strata  or  beds  of  stone, 
the  one  of  which  lies  above,  and  the  other  below  this  vein,  like  a  stratum  of  coal  between 
its  roof  and  pavement :  so  that  the  vein  and  strata  are  placed  in  the  same  plane  of  inclina- 
tion. These  veins  are  subject,  like  coal,  to  be  interrupted,  broken,  and  thrown  up  or  down 
by  slips',  dykes,  or  other  interruptions  of  the  regular  strata.  In  the  case  of  a  metallic  vein, 
a  slip  often  increases  the  chance  of  finding  more  treasure.  Such  veins  do  not  preserve  the 
parallelism  of  their  Ijeds,  characteristic  of  coal  seams,  but  vary  excessively  in  thickness 
within  a  moderate  space.  Flat  veins  occur  frequently  in  limestone,  either  in  a  horizontal 
or  declining  direction.     The  flat  or  strata  veins  open  and  close,  as  the  rake  veins  also  do. 

4.  The  interlaced  mass  has  l)een  already  defined.  The  interlaced  strings  are  more  fre- 
quent in  primitive  formations,  than  in  the  others. 

To  these  may  be  added  the  accumulated  vein,  or  irregular  mass,  (butzcnwerke,)  a  great 
deposit  placed  without  any  order  in  the  bosom  of  the  rocks,  apparently  filling  up  cavernous 
spaces. 


MINIiN-G. 


755 


In  Cornwall  and  Devonshire,  wbere  different  conditions  prevail,  other  terms  are  em- 
ployed. 

The  lode,  or  mineral  vein,  is,  as  in  the  former  instances,  a  great  line  of  dislocation, 
accompanied  by  minor  lines  of  fracture.  Of  these  Sir  H.  De  la  Beche  says :  "  It  could 
scarcely  be  supposed  that  the  great  lines  of  fracture  would  be  unaccompanied  by  smaller 
dislocations,  running  from  them  in  various  directions  according  to  modifying  resistances, 
which  would  depend  upon  the  kinds  of  rock  traversed  by  the  great  fractures,  the  direction 
in  which  they  were  carried  through  them  as  regards  the  bearing  of  their  strata,  should  they 
be  stratified,  and  other  obvious  causes.  The  great  fractures  would  often  also  tend  to  split 
in  various  directions  and  reunite  into  main  hngs,  as  in  the  annexed  sketch,  {Jig.  431,)  in 


which  a  b  represents  the  line  of  principal  fracture,  splitting  at  J  6  from  local  causes,  and 
uniting,  both  towards  a  and  6,  minor  cracks  running  into  the  adjoinmg  rock  at  c,  c,  c,  c. 
These  are  known  as  side  lodes,  strings,  feeders,  and  branches. 

These  strings  are  sometimes  very  curiously  developed,  and  illustrate  the  peculiar  force 
of  crystalline  action,  and  all  the  phenomena  of  heaves  and  faults.  The  following  figure 
(432)  furnishes  a  good  illustration. 

It  represents  a  specimen  of  strings  of  oxide  of  tin  in  slate  from  St.  Agnes,  Cornwall, 
h,  h,  illustrating  the  heaves  alluded  to.  Sir  Henry  De  la  Beche  is  disposed  to  refer  these  to 
the  fact  of  oxide  of  tin  recementiug  fractured  masses  of  slate.  AVe  think  we  have  sufficient 
evidence  for  referring  the  action  to  the  crystallogenic  force  enlarging  a  fissure,  or  small 
crack,  and  producing  those  lateral  cracks,  wliich  again,  by  the  operation  of  the  same  force, 
dislocate  or  heave  the  original  fissure. 

In  these  lodes  we  find  peculiar  mechanical  arrangements,  which  are  known  by  various 
names ;  a  lode  is  said  to  be  coinby  when  we  have  the  crystals  of  quartz  or  other  mineral 
dovetailing,  as  it  were,  with  the  metalliferous  masses.  Bunches  are  isolated  masses  of  ore 
found  in  the  lode  surrounded  by  earthy  minerals.  The  upper  part  of  a  lode  is  known  as 
its  hack,  and  the  accumulations  of  ferruginous  matter  which  very  commonly  occur  in  the 
backs  and  near  the  surface,  are  known  as  gossans.  These  are  to  the  experienced  miner  im- 
portant guides  as  indicating  the  characters  of  the  lode  at  a  greater  depth.  The  country  sig- 
nifies, with  the  Cornish  miner,  the  rock  through  which  the  mineral  vein  runs,  and  accord- 
ingly as  he  is  pleased  with  the  indications  he  speaks  of  its  being  kiiidly  or  the  contrary. 
The  softer  rocks,  whether  of  clay-slate  or  granite,  are  spoken  of  as  plumb,  and  a  plumb 
granite,  or  elvan,  is  greatly  preferred  to  the  harder  varieties,  and  spoken  of  as  being  more 
kindly. 

The  rock  forming  the  sides  of  a  lode  are  known  as  its  walls  or  cheeks.  The  latter  term 
we  have  heard  of  late  years  in  Corn^^Pall,  but  we  believe  it  to  be  imported  by  miners  who 
hAve  worked  in  the  north  of  England.  As  all  mineral  veins  incline  more  or  less,  the  sides 
are  spoken  of  as  the  upper  and  under  walls,  the  upper  being  usually  termed  the  hanging 
wall. 

The  following  wood-cuts  {figs.  433,  434)  will  serve  to  assist  the  reader  in  understanding 
the  peculiarities  of  mining  operations  in  our  metalliferous  mines.  In  fig.  434,  which  is  a 
section  of  one  of  the  lead  mines  of  Cardiganshire,  the  shafts,  which  have  been  sunk  on  the 
lode  are  shown,  at  varied  angles  from  the  vertical  and  the  several  horizontal  levels.  In 
this  instance  these  levels  or  galleries  have  been  worked  at  irregular  distances.  In  Cornwall 
they  are  usually  ten  fathoms  apart.  The  smaller  shafts  connecting  the  levels  one  with  the 
other  are  called  ivinzes.  They  serve  for  exploring  the  lode,  or  for  purposes  of  ventilation, 
when  the  excavations  are  going  forward.  When  these  smaller  connected  shafts  are  worked 
upwards,  as  they  sometimes  are,  they  are  called  "  risings,"  and  the  miner  is  said  to  be  work- 
ing on  the  "  f«e."  In  this  wood-cut  the  lightest  shading  is  to  indicate  a  portion  of  this  par- 
ticular mine  which  was  worked  out  by  the  Romans.  The  darker  shaded  ma.sses  indicate 
portions  of  the  lode  which  have  been  very  productive  of  metalliferous  matter,  and  which 
have  consequently  been  removed.  The  term  counter  or  caiinter  lode  is  given  to  such  lodes 
as  dip  at  a  considerable  angle  with  the  direction  of  the  other  lodes  in  its  vicinity.  Such  a 
lode  is  shown,  (fig.  433,)  which  is,  however,  inserted  principally  to  explain  that  where  the 
"  underlie"  of  the  lode  is  great,  a  vertical  shaft  is  sunk  at  some  distance  from  it  on  the  sur- 
face, so  as  to  "  cut "  (intersect)  the  lode  at  some  depth,  in  this  instance  at  70  fathoms  below 
the  adit-level.  As  the  inclination  of  the  lode  then  alters,  the  shaft  is  continued  on  the 
lodes.  Another  fissure  or  lode,  sometimes  called  a  ^^  dropper,"  is  seen  to  take  nearly  a 
vertical  direction  from  the  50-fathom  level,  and  from  the  shafts  levels  are  driven  into  this 
lode,  at  about  evcrv  10  fathoms. 


756 


MINING. 


Fig.  435  represents  in  plan  the  underground  workings  of  a  Cornisli  mine.     Those  who 
are  not  familiar  with  mining  are  requested  to  suppose  that  the  earth  is  transparent  so  as  to 


432 


enable  us  to  see  the  levels  worked  at  various 
depths,  from  the  adit-level — through  which 
the  water  pumped  from  the  mine  is  dis- 
charged—to the  125-fathom  level  below  it. 
These  levels  arc  numbered  in  the  plan.  They 
are  not  worked  immediately  under  one  ano- 
ther ;  but,  as  the  lode  inclines,  in  the  same 
way  as  is  shown  in  the  Caunter  Icde,  {fig. 
438,)  they  follow  in  position  this  underlie 
of  the  lode.  The  dark  lines  and  the  dotted 
lines  crossing  the  numbered  lodes,  are  work- 
ings upon  lodes,  running  in  a  contrary  di- 
rection to  the  lode  principally  shown.  This 
plan  shows  the  junction  of  the  granite  with 
the  killas  or  claii-4ate  of  Cornwall,  and  the 
occurrence  of  elvan  courses  is  shown  at  the 
diiferent  levels.    By  studying  the  plan,  with 

433 


fKD/T        LBVEL 


the  horizontal  and  transverse  section,  the  operations  of  metalliferous  mining  will  be  under- 
stood. 


MINING. 


757 


In  all  mines,  to  a  greater  or  a  less  extent,  there  will  be  found  accumulations  of  water ; 
it  is  necessary,  therefore,  to  adopt  measures  to  ensure  its  removal.     The  mineral  treasures, 


435 


'••'•VX'- 


<t35a 


being  brought  to  the  surface,  necessarily  undergo  a  process  of  "  dressing,"  that  is,  the  sepa- 
ration of  the  richer  from  the  poorer  portion.  For  a  full  account  of  dressing  machinery, 
&c.,  see  Ores,  Dressing  of,  and  Water  Pressure  Machinery. 

It  sometimes  happens  that  the  necessities  of  mining  demand  the  construction  of  shafts 
in  places  covered  with  water.  Some  years  since  a  very  extraordinary  case  of  this  kind 
was  to  be  seen  at  the  Wherry  Mhie,  near  Penzance,  where  a  cj'linder  of  wood,  rising  through 
the  sea,  formed  the  entrance  to  a  shaft  sunk  into  the  mine.  In  a  storm  a  ship  ran  against 
this  timber  structure  and  destroyed  it. 

M.  Triger,  engineer  in  the  department  of  Maine  and  Loire,  had  the  idea  of  making  a 
well  in  the  very  bed  of  the  Loire 
by  means  of  compressed  air.  A 
cylinder  of  thin  iron,  ( iig.  43orT,) 
served  as  a  cutting  machine,  was 
sunk  into  the  alluvium ;  it  was 
separated  into  three  compartments 
by  horizontal  partitions.  The  up- 
per compartment  remained  always 
open,  the  lower  compartment  was 
the  workshop,  and  between  them 
was  the  middle  one,  which  served 
as  the  chamber  of  equilibrium,  de- 
signed to  be  put  in  communication 
with  either  the  compartment  above 
or  the  one  below.  The  things  be- 
ing so  disposed,  they  forced  into 
the  bottom  compartment,  air  com- 
pressed by  a  vapor  machine  with- 
out intermission.  This  air  drove 
the  water  up  a  tube,  of  which  the 
lower  part  was  buried  in  the  bot- 
tom of  the  excavation,  and  of  which 
the  upper  part  was  raised  above 
the  cylinder.  The  workmen  were 
then  able  to  penetrate  the  first 
apartment  and  open  the  second, 
which  was  afterwards  hermetically 
closed,  and  in  which  the  air  of  or- 
dinary pressure  was  put  in  com- 
munication with  the  compressed 
air  in  the  third.  Having  arrived  in 
the  third  compartment  they  exca- 
vate the  sands,  and  cause  the  ma- 
chine to  descend.  As  they  accu- 
mulate the  sands  excavated  in  the 
middle  compartment,  they  have 
only  to  remove  tliem  by  shutting 
the  communication  with  the  bottom 
and  opening  that  of  the  top.  A 
pressure  sufficient  to  balance  the  exterior  waters  was  maintained  during  the  work,  without 
sensibly  incommoding  tlie  workmen.     This  ingenious  proceeding  has  since  received  numer- 


Y58 


MINT. 


ous  applications.  In  fig.  435a  is  represented  the  apparatus  as  it  was  used  by  M.  Triger  at 
the  bottom  of  the  Loire. 

It  is  evident  that  wells  dug  in  the  water-saturated  earths  must  immediately  be  cased, 
that  is  to  say,  covered  with  a  casing  of  wood,  solid  and  impermeable,  which  is  able  to  resist 
the  infiltration  and  pressure  of  the  waters  at  the  same  time. 

A  plan  similar  to  this  was  employed  by  Mr.  Brunei  in  the  construction  of  one  of  the 
piers,  in  the  bed  of  the  river  Tamar,  for  the  Royal  Albert  Bridge  at  Saltash. 

MINT.  At  the  Mint,  gold,  silver,  and  copper  are  converted  into  coin  of  the  realm,  but 
as  the  processes  are  nearly  similar,  it  is  only  necessary  to  describe  the  coining  of  gold,  and 
to  point  out  briefly  the  difl'erence  in  the  manufacture  of  copper  coin,  because  silver  under- 
goes precisely  the  same  operations  as  gold,  the  same  machinery  being  used  for  all  three 
metals.  Copper  is  rolled  from  red-hot  slabs  of  copper,  about  12  inches  long  by  10 
inches  broad,  and  1  inch  thick,  by  five  pinches,  down  to  a  slab  between  3  and  4  feet  long, 
by  14  inches  broad,  and  020  of  an  inch  thick ;  the  slab  is  then  cut  in  half,  digested  for  10 
minutes  in  beer  grounds,  and  heated  to  redness ;  it  is  then  plunged  into  cold  water  as 
rapidly  as  possible,  by  which  means  the  thick  scale  of  red  oxide  of  copper,  which  forms 
during  the  rolling,  is  separated ;  but  as  small  particles  of  the  scale  still  remain,  the  slabs 
are  scratched  by  men  with  brushes  made  of  brass  wire  until  perfectly  clean ;  it  is  then  cut 
into  ribbons  or  fillets  of  a  convenient  width,  by  a  pair  of  circular  shears.  Fig.  436  shows 
these  shears,  a  and  b  being  cogged  wheels  supported  on  shafts,  which  each  terminate  in 

436 


plates  of  iron  supporting  circular  plates  of  hard  steel,  e  f.  The  inner  surface  of  f  is  pressed 
against  by  the  outer  surface  of  e,  which  is  provided  with  a  screw,  k,  at  the  extreme  end  of 
its  shaft  fcr  this  purpose,  d  is  a  cogged  wheel  reversing  the  motion  which  would  otherwise 
be  given  to  b,  so  as  to  cause  the  shears  to  revolve  in  opposite  directions,  and,  in  fact,  the 
shears  may  be  viewed  as  endless  scissors  driven  by  machinery.  The  copper  slabs  are  rested 
on  the  plate  n,  and  the  width  of  the  fillet  to  be  cut  is  determined  by  fixing  the  gauge  g  at 
any  required  point ;  this  having  been  aiTanged,  the  slabs  are  steadied  and  pushed  lightly 
against  the  point  at  which  e  f  touch,  and  by  the  motion  of  the  plates  are  drawn  through 
and  cut  or  sheared  at  the  same  time.  Copper  fillets  do  not  pass  through  the  drag  bench,  as 
is  presently  explained,  for  gold.  The  only  other  difference  in  the  processes  copper  under- 
goes, is  that  it  is  blanched  by  a  bath  of  from  20  to  30  hours  in  cold  diluted  sulphuric  acid. 
Silver  is  bought,  through  the  brokers,  by  the  Master  of  the  Mint,  cither  in  the  form  of 
foreign  coin  (5-franc  pieces  are  preferred)  or  ingots,  and  to  the  silver  .«o  obtained  is  added 
so  much  copper  or  pure  silver,  as  shall  bring  the  whole  mass  up  to  the  standard  silver  of 
the  realm,  which  consists  of  222  parts  of  silver  and  18  parts  of  copper.  The  metal  so 
arranged  is  weighed  out  into  charges  of  about  4,000  ounces  for  the  wrought-iron  melting- 
pot,  which  is  represented  in  fig.  437,  as  seen  in  the  furnace  e  standing  on  the  "  bottom  a," 
which  rests  on  the  fire  bars,  and  is  made  partially  cup-shaped  and  filled  with  powdered  coke, 
that  the  bottom  of  the  pot  b  may  be  perfectly  supported,  while  at  the  same  time  it  is  pro- 
tected from  the  current  of  air  which  is  supplied  to  the  furnace.  Powdered  coke,  being  a 
bad  conductor,  prevents  the  free  passage  of  heat  from  the  base  of  the  pot  to  the  "  bot- 
tom," and  the  consequent  probable  fusion  of  the  two  through  the  agency  of  the  oxide 
of  iron,  which  fbrms  and  accumulates  whenever  iron  is  repeatedly  heated,  d  is  the  lid  of 
the  pot,  and  c  the  muffle  or  funnel,  against  the  sides  of  which  the  metal  rests  during  the 


MINT. 


759 


487 


process  of   fusion,  to   prevent  its  falling  over  into  the  burning  coke.      The  pot,  when 

charged,  is  allowed  to  remain  in  the  furnace  till  the  metal  has  fused,  and  the  temperature 

has  risen  to  a  point  little  short  of  that  which  would  so  far  soften  the  wrought  iron  pot  as 

to  cause  it  to  lose  its  shape.     The  pot  is  lifted  by 

the  tongs  t,  of  the  crane,  3,  from  the  furnace  f, 

(after  the  fire  has  been  removed   by  diyplacing 

some  of  the  fire-bars,)  swung  round  and  dropptd 

into  the  cradle  m,  of  Jig.  438,  when  it  is  secured 

by  a  screw,  which  draws  tight  the  band  at  the  top 

The  melted  silver  is  then  thoroughly  stiired  with 

an  iron  rod,  and  all  being  ready,  the  frame  of 

moulds,  A,  is  run  under  the  cradle  stand  so  far  as 

to  allow  the  rack  b  to  work  into  the  wheel  n.     The 

foreman  then,  by  means  of  the  handle  d,  which 

communicates  by  e  with  the  cradle  in  which  the 

pot  is  fixed,  raises  the  pot,  and  tilts  it  so  much  as 

is  necessary  to  pour  the  fluid  silver  into  the  mould 

until  it  is  filled  ;  he  then  lowers  the  pot,  and  waits 

while  an  assistant  by  the  handle  o,  connected  with 

the  cog-wheel  n,  moves  the  moulds  forward  as  they 

are  required  to  be  filled.     The  moulds  are  ranged 

side  by  side  in  the  frame,  and  pressed  firmly  to 

gethcr  by  screws  at  the  ends  of  the  mould-frames, 

and  secured  in  front  by  two  bars  of  iron,  g,  whii^h  fit  into  wedge  shaped  grooves,  slanting 

forwards. 


The  metal  solidifies  immediately,  and  the  pot  having  been  emptied,  the  carriage  of 
moulds  is  run  on  its  wheels  Q,  from  under  the  cradle  frame,  and  the  screws  having  been 
loosened,  the  moulds  are  caused  to  fall  to  pieces,  and  each  bar,  as  it  is  exposed,  is  taken  by 
tongs  and  plunged  into  cold  water,  as  much  to  save  time  as  to  soften  the  bar  by  sudden 
cooling.  The  bars  produced  from  the  whole  pot  of  metal  are  numbered  with  a  distinctive 
figure  to  designate  the  pot,  and  with  two  letters  to  indicate  the  day's  melting ;  assay  pieces 
are  then  cut  from  the  first,  middle,  and  last  bars  of  the  set.  The  assay  pieces  are  properly 
secured,  certified,  and  sent  to  the  non-resident  assayers  of  the  Jlint.  (For  an  account  of 
this  process,  see  Assay.)  In  the  event  of  the  assay  being  unsatisfiictory,  the  pot  is  stopped, 
and  the  metal  is  adjusted  as  to  quality  and  remclted.  The  assays  being  satisfactory,  the 
bars  arc  forwarded  to  the  coining  department,  where  they  undergo  the  same  process  of 
manufacture  as  gold  is  subjected  to. 

Gold  is  sent  by  the  Bank  of  England  to  the  Mint  in  the  form  of  ingots,  which  average 
about  180  ounces  each,  and  arc  assayed  by  the  resident  assayers  in  the  Mint,  who  make  a 


760 


MINT. 


439 


report  to  the  Master.  The  Master  directs  the  addition  of  so  much  pure  copper,  or  pure 
gold,  as  will  make  the  whole  into  standard  gold,  which  consists  of  22  parts  of  pure  gold  and 
2  parts  of  pure  copper,  making  what  is  technicallly  termed  standard  gold,  and  in  these  pro- 
portions the  gold,  with  its  alloy,  is  sent  to  the  melting  house. 

Since  gold  requires  so  high  a  temperature  for  its  fusion,  it  would  be  unwise  to  attempt 
to  fuse  it  in  iron  pots,  consequently  the  so-called  black-lead  pots  (for  a  description  of  which 
see  Crucible)  are  used.  Fig.  439  demonstrates  the  position  of  the  pot  as  it  would  appear 
if  in  the  furnace  ;  n  represents  the  "  bottom,"  which  is  usually  obtained  by 
breaking  a  worn-out  pot  into  a  convenient  form  ;  a  is  the  pot,  b  the  muffle, 
which,  as  in  the  case  of  silver,  answers  the  purpose  of  a  funnel,  to  guide 
the  metal  during  the  time  of  fusion  into  the  pot ;  c  is  the  top,  or  lid  of  the 
pot.  Care  is  required  in  using  black-lead  pots,  else  the  small  amount  of 
moisture  which  they  absorb  from  the  atmosphere  causes  the  fracture  of  the 
pot  when  it  is  suddenly  heated,  therefore  the  pot  is  dried  carefully  before  it 
is  used ;  and  when  required  for  use,  is  placed  in  the  furnace  with  a  small 
fire,  which  gradually  increases  in  temperature  to  a  full  white  heat,  the  pot 
becoming  by  this  process  annealed,  and  is  then  seldom  liable  to  fracture 
unless  badly  used.  The  pot  and  furnace  being  ready,  the  gold,  and  its  alloy 
previously  weighed  out  in  charges  of  about  1,200  ounces,  but  varying 
slightly  according  to  the  size  of  the  ingots  which  compose  the  charges,  are 
placed  carefully  in  the  pot.  As  fusion  ensues,  the  molten  mass  is  stirred 
witli  a  rod  made  of  the  same  substance  as  the  pot  itself.  In  fusing  both  standard  gold  and 
standard  silver,  it  is  customary  to  place  either  small  pieces  of  charcoal  or  powdered  char- 
coal at  the  bottom  of  the  pot  before  placing  the  metal  in  the  pot ;  then  as  the  metal  fuses 
it  runs  down  and  rests  upon  the  fine  particles  of  charcoal ;  when  the  fusion  is  complete,  the 
charcoal  is  released  from  the  bottom  of  the  pot  by  the  process  of  stirring,  and  as  it  rises 
balloon-like  through  the  fused  or  molten  mass,  it  reduces  any  oxide  of  copper  which  may 
have  been  formed  during  fusion,  and  resting  on  the  surface  of  the  fluid  metal  protects  it 

from  the  atmosphere  dui'ing  the  time  of  pour- 
440  ing.     The  pot  is  lifted  from  the  furnace  after 

the  removal  of  the  firing  by  a  hand  crane,  and 
it  is  then  taken  by  a  pair  of  long  tongs,  as 
shown  in  Jig.  440,  by  the  foreman,  who  passes 
the  little  button  at  the  end  of  the  tongs  through 
a  loop  of  iron,  a,  suspended  by  a  rope  which 
passes  to  the  ceiling  and  through  a  pulley  down 
to  an  assistant,  who  by  this  means  bears  the 

441 


weight,  and  regulates  the  height  of  the  pot,  while  the  foreman  pours  the  metal  into  the 
moulds  B,  fixed  in  the  frame  c,  which  runs  on  wheels  in  a  tramway.  Three  pieces  of  planed 
iron  form  two  moulds,  as  shown  in  fig.  441,  where  D„  Eg,  f,o,  show  the  form  of  these  planed 
pieces,  and  the  manner  of  placing  "tllem  together.  The  bars  are  solidified  immediately,  and 
when  all  the  moulds  have  been  filled,  they  are  taken  to  pieces  and  the  bars  plunged  into 
cold  water,  with  the  same  object  as  in  the  case  of  silver.  From  the  bars  obtained  from  each 
pot,  two  pieces  are  cut  off  for  assaying,  by  the  non-resident  assayers,  the  bars  being  num- 
bered according  to  the  pot  from  which  they  were  poured,  and  lettered  distinctively,  accord- 
ing to  the  dav  on  which  they  were  melted.  Should  the  assay  prove  unsatisfactory,  the  metal 
is  adjusted  and  remclted  "if  the  assays  are  satisfactory,  the  bars  are  forwarded  to  the  coin- 
ing depot. 

In  the  coining  department  the  first  operations  are  performed  in  the  rolling  room,  which 
is  provided  with  very  powerful  machinery  for  driving  six  pairs  of  rollers  made  of  chilled 
cast-iron.  Fig.  442Vepresents  one  pair  of  these  rollers,  Avhich  are  used  for  breaking  down 
the  bars  partially  to  the  form  of  fillets  or  ribbons ;  they  are  driven  by  a  40  horse  steam- 
engine,  and  revolve  in  opposite  directions,     a  represents  the  rollers,  which  are  of  14  inches 


MINT. 


761 


diameter.  The  upper  one  is  supported  by  a  pair  of  strong  brasses  bolted  together,  f  f. 
From  the  lower  brass  proceeds,  as  may  be  seen  in  frj.  442,  a  rod  b,  which  passes  through 
the  solid  masonry,  and  communicates  witli  a  counterpoise  weight  n,  placed  on  a  long  lever 
whose  fulcrum  is  N.     The  object  in  counterpoising  tho  upper  roller  is  to  ensure  the  removal 

442 


443 


of  all  pressure  which  is  not  mtentionally  applied  in  the  process  of  rolling,  f  shows  a  cap- 
stan head,  the  copper  ring  on  which  is  divided  into  50  parts,  an  indicator  being  fix'ed  to  the 
main  frame  of  the  mill.  The  handle  g  moves  two  endless  screws  which  work  into  the  teeth 
of  the  wheels  f,  which  are  supporttid  by  powerful  screws,  passing  through  the  main  frame 
of  the  mill,  and  touching  the  upper  brass  of  the  upper  roller  at  c.  By  this  means  any 
pressure  which  is  deemed  wise  can  be  exerted  on  a  bar  placed  between  the  rollers.  Tlie 
sovereign  bars  are  wrought  in  pairs,  and  five  pairs  make  one  batch,  a  number  of  bars  which 
is  found  most  convenient  to  work  at  the  same  time. 
A  sovereign  bar  is  21  inches  long,  1-375  inch  broad, 
and  1  inch  thick.  The  first  process  is  to  submit  the 
bars  to  six  pinches  between  the  rollers,  by  which  they 
are  reduced  to  0194  inch  thick,  and  become  1-712 
inch  broad,  at  which  stage  the  hollow  ends  are  sheared 
off,  and  the  bars  are  cut  into  lengths  of  18  inches ; 
they  are  then  placed  in  5  copper  tubes  a,  as  shown  in 
fifi.  443,  the  tops  of  which  are  carefully  luted  on  with 
clay,  and  the  copper  tubes  are  then  placed  on  a  small 
cast-iron  carriage  b,  and  run  into  the  annealing  fur- 
nace c.  After  20  minutes'  annealing  at  a  full  red 
heat,  tlie  carriage  is  withdrawn  ;  the  tubes  taken  one 
by  one  in  tongs,  and  plunged  as  rapidly  as  po.  si  )le 
into  cold  water.  It  is  found  that  rapidly  cooling  ren- 
ders gold,  silver,  and  copper  soft  and  tougii,  while  it 
renders  iron  and  steel  hard  and  brittle.  Therefore  the 
more  rapidly  the  gold  is  cooled,  the  grcatcr*the  result 
as  to  the  softening  of  the  bars.  After  annealing,  the 
bars  go  back  to  the  breaking-down  mill,  and  receive 
six  pinches,  by  which  they  are  reduced  to  0-120  inch 
thick",  and  1-778  inch  wide,  and  are  now  called  fillets, 
and  are  gauged  by  a  wedge-shaped  instrument  shown 
in  jirj.  444,  which  is  simply  a  hollow  wed.i^e,  graduated 
into  thousandths  of  an  inch,  tiie  great  oliject  being  to 
ascertain  if  both  sides  of  tlie  fillets  are  of  the  same  thickness,  which  is  done  by  placing  a 
fillet  in  the  graduated  opening  between  a  and  n.     The  bars  reduced  to  0-120  inch  thick, 

444 


are  passed  to  a  finer  pair  of  rollers,  under  which  they  receive  si.x  pinches,  and  are  then 


762 


MINT. 


passed  to  a  still  finer  pair  of  rollers,  until  at  last,  after  1 1  pinches,  they  arrive  at  the  gaug- 
ing mill,  which  is  as  accurate  as  rollers  can  be  made  to  be  ;  but  at  this  stage  the  officer  in 
charge  frequently  overlooks  the  professional  gauger,  and  by  his  gauge  tests  the  fillet  in 
every  part,  so  as  to  determine  that  it  is  of  the  same  thickness  throughout  its  entire  length 
and  breadth.  Fiys.  445,  446  show  a  plan  of  the  gauge,  which  is  used  only  by  the  officer  in 
charge,  because  it  is  a  most  delicate  instrument,  and  is  capable  of  measuring  to  one  ten- 
thousandth  part  of  an  inch,  which  it  gives  by  a  single  reading.     The  instrument  was  made 

445 


with  great  care  by  Mr.  Becker,  of  the  firm  of  Messrs.  Elliott,  30  Strand,  and  is  found  prac- 
tically to  give  most  accurate  results,  d  c  shows  the  point  at  which  any  substance  to  be 
measured  is  placed.  The  upper  rod  of  steel  c,  rests  upon  the  lower  one  d,  and  passes  to 
the  handle  of  the  instrument,  terminating  in  a  lever  b,  by  which  it  can  at  any  moment  be 
drawn  backward  if  the  lever  be  pressed  by  the  thumb  while  the  handle  a  is  firmly  held  by 
the  same  hand.  The  rod  c  is  provided  at  f  with  a  rack,  into  which  a  small  pinion  works, 
carrying  an  indicator  E,  which  traverses  over  an  accurately  divided  scale  with  500  divisions. 
If  now  the  space  of  the  point  d  c  be  opened  0-50  an  inch,  the  indicator  travels  over  the 
whole  500  divisions  on  the  face,  and  as  the  hand  itself  carries  a  vernier  g,  which  gives  the 
tenth  of  a  thousandth  of  an  inch,  we  have  by  the  first  reading  the  division  of  one  inch 
which  indicates  the  O'COOl  part.     The  gauge  can  be  used  to  measure  up  to  3  inches  by 

44V 


drawing  back  the  lever  b,  until  the  zero  of  g  points  to  500,  when  the  rod  c  is  secured  by  a 
damp  at  a,  and  the  rods  c  d  are  drawn  out  till  the  zero  of  G  points  to  the  zero  of  the  dial 


MINT. 


763 


plate  ;  the  screws  h  are  then  again  secured,  and  he  proceeds  as  before.  When  the  fillets 
leave  the  gauging  mill  they  must  be  2  inches  bioad,  and  must  not  vary  O'OOOOl  of  an  inch  in 
thickness  from  one  part  to  another.  Besides  the  examination  by  the  officer,  the  gauger 
strikes  out  occasionally  one  or  two  blanks  from  the  fillets,  to  see  that  the  rollers  have  not 
altered  ;  great  danger  of  alteration  arising  from  the  fact  that  the  middle  of  the  fillet  wears 
away  the  roller  more  than  its  sides  do,  so  that  the  middle  is  evidently  liable  to  become 
thicker  than  the  sides ;  and  if  this  fault  once  arises,  it  is  found  to  give  great  trouble  in 
future  operations.  As  the  greatest  deUcacy  is  required  at  the  gauging  mills,  another  and 
more  accurate  system  of  adjusting  is  adopted.  Fig.  447  shows  a  side  view  of  the  gauging 
mill :  a,  b,  the  rollers  ;  e  is  a  wedge  which  travels  under  the  brass  of  the  lower  roller,  which 
is  cut  to  fit  the  wedge  exactly.  The  wedge  e  is  forced  forward  by  the  gear  work  g,  which 
sets  the  screw  /  in  motion,  giving  the  most  minute  adjustment.  At  d  is  an  opening  to 
allow  the  supply  of  oil  to  the  neck  of  the  upper  roller.  The  fillet  as  it  travels  onwards 
rests  on  the  apron  I. 

The  fillets  are  now  so  accurate  that  a  blank  struck  from  any  part  of  them  seldom  varies 
more  than  0-40  or  0-60  grain,  but  are  left  so  thick  that  a  blank  weighs  8  grains  more  tha 


448 


449 


450 


a  coined  sovereign  should  weigh ;  the  object  in  leaving  it  so  heavy  being  that  it  may  under- 
go far  more  delicate  operations,  so  as  to  reduce  the  variations  of  thickness  as  much  as  pos- 
sible. 

The  fillets  now  pass  on  to  the  drag  room,  where  a  boy  passes  them  twice  through  a  pair 
of  very  delicate  adjusting  rollers,  and  another  boy  trims  one  end  of  each  fillet  by  a  pair  of 
shears,  and  passes  the  end  so  trimmed  into  an  opening  between 
a  pair  of  rollers,  shown  at  Jigs.  448,  449,  and  450,  where  the 
fillet  is  shown  in  c  as  being  passed  between  the  revolving  rollers 
A  B,  at  the  time  that  the  surface  of  b  which  is  cut  away  presents 
itself  and  admits  of  the  free  passage  of  the  fillets  to  the  stop  or 
gauge  D.  As  the  roller  b  revolves  towards  c,  it  Ci;rries  the  fillet 
with  it,  and  at  the  same  time  reduces  the  thickness  as  much  as  is 
required.  The  distance  between  the  rollers  a  n  is  regulated  by 
the  pinions  e,  which  turn  screws  resting  on  the  brasses  of  a.  The 
Hatting  mill,  for  so  it  is  called,  is  driven  Ijy  a  strap  passing  over 
the  drum  n  ;  the  shaft  of  which  carries  a  small  pinion  a  working 
into  F.  To  relieve  the  weight,  the  fillet  is  rested  on  l.  The  end 
which  is  called  flatted  becomes  by  this  pressure  about  one-third 
tliinncr  than  the  other  part  of  the  fillet,  and  it  is  usual  to  flat 
about  three  inches  of  the  fillet. 

Tiie  flatted  fillets  are  then  taken  to  the  drag  bench,  where 
they  are  made  to  pass  by  main  force  through  an  opening,  in 


704 


MINT. 


which  is  fixed  a  pair  of  small  cylinders  of  the  hardest  steel,  exactly  fitting  into  beds  which 
hold  them  rigidly,  and  prevent  the  most  minute  movement.  Figs.  451  and  452  give  a  full 
view  of  the  drag  bench ;  a  represents  drums,  over  which  the  endless  chain  b  passes ;  the 

451 


drum  A,  at  the  end  where  it  is  shown  as  moved  by  the  cogged  wheel  c,  is  cut  in  deep  grooves 
to  the  depth  of  about  two  inches,  and  into  these  grooves  the  bar  of  the  chain  fits  so  that  as 
the  drum  revolves  it  drags  the  chain  with  it.  The  drum  at  the  other  end  is  plain,  and  is 
therefore  simply  a  carrier  of  the  chain,  which,  as  it  travels  on  the  upper  surface  of  the 
bench,  fits  into  a  trench  provided  for  it.  The  machine  is  driven  by  the  drum  g,  which  is 
connected  by  its  shaft  with  F,  which  drives  the  wheel  e,  havihg  on  its  shaft  the  small  wheel 
D,  which  finally  drives  c.  There  are  two  drag  benches,  and  each  has  two  chains,  so  that  the 
wheel  E  becomes  a  common  motion  for  two  chains.  Fig.  452  shows  a  section  of  the  drag 
licad  with  the  dog  in  the  act  of  dragging  a  fillet  through  the  opening  n.  In  using  the  drag 
bench  the  flatted  end  of  tiie  fillet  is  passed  by  tlie  hand  into  the  opening  between  the  bars 
F  where  the  small  cylinders  are  shown  at  x  to  be  fixed  in  the  blocks  d  in  the  opening  n  ; 
the  dog  is  now  brought  up  by  the  handle  s,  until  the  mouth  a  is  pressed  into  the  opening 


452 


453 


[tft   ^E    iBi 


N,  when  the  rods  i  open  the  jaws,  which  are  cut  with  a  good  set  of  teeth,  and  seize  the  end 
of  the  fillet  as  it  protrudes.  The  handle  attached  to  the  weight  h  is  then  lifted,  and  e  is 
depressed  until  its  hook  catches  into  a  cross-bar  of  the  travelling  chain  b,  when  it  is  drawn 
on.  The  dog  travels  on  wheels  d,  whose  axle  here  becomes  a  wedge  acting  upon  the  long 
end  of  e,  and  so  causes  the  fillet  to  be  held  tight  in  proportion  to  the  resistance  offered  to 
its  passage  between  the  cylinders.  The  handle  of  r  is  never  used,  because  it  is  too  far  for 
the  dragsmen  to  reach  with  convenience,  but  the  hooks  whicli  catch  tlie  cliain  are  sliown  at 
f.  Fiq.  453  gives  a  furtlier  view  of  tlie  drag  head  ;  it  consists  of  a  very  firm  frame  of  iron 
provided  at  the  top  with  an  horizontal  wheel  ii  which  works  a  fine  cut  screw.  The  cylin- 
ders are  fixed  in  the  blocks  n,  which  are  held  to  their  positions  by  screws  at  the  side  ;  the 
lower  block  d  is  regulated  as  to  height  by  screws  from  below,  and  the  upper  block  d  be- 
comes the  only  movable  one.  If  it  is  required  to  bring  the  cylinders  closer  together,  the 
dragsman  does  it  by  moving  the  handle  o,  which  communicates  by  its  pinion  p  with  the 
wheel  H.  It  is  almost  needless  to  say  that  by  this  arrangement  the  most  minute  alterations 
can  be  made  in  the  thickness  of  the  fillet,  and  it  frequently  happens  that  so  minute  an  ad- 
justment is  made  as  to  show  a  difference  of  only  half  a  grain  upon  47  sovereign  blanks ; 


MINT. 


765 


and  if  it  be  remembered  that  a  thickness  of  O'OOl  inch  on  a  sovereign  blank  equals  0'125 
of  a  grain,  it  will  be  conceived  that  the  distance  which  the  cylinder  is  made  to  travel  by 
this  most  beautiful  micrometric  arrangement  is  very  small.  The  drag  bench  was  invented 
by  the  late  Mr.  Barton,  and  may  be  viewed  as  the  greatest  addition  to  the  machinery  of  the 
Mint  ever  yet  or  ever  likely  to  be  introduced  ;  for  by  its  agency,  when  intelligently  man- 
aged, the  fillets  of  silver  coming  from  it  are  so  perfect  that  for  days  together  the  blanks  cut 
from  them  are  found  to  contain  only  1  in  400  out  of  remedy,  and  it  is  quite  a  common  oc- 
currence to  find  only  1  in  800,  and  from  gold  fillets  blanks  are  cut  in  which  only  1  in  100, 
and  even  1  in  200  are  rejected  as  being  out  of  remedy. 

To  the  drag  bench  are  fixed  two  pairs  of  hand  shears,  by  which  the  fillets  are  cut  into 
four  lengths.  They  are  then  passed  on  to  the  trier,  who,  by  the  hand-cutter  shown  at  Jig. 
454,  punches  out  one  or  more  blanks  from  each  piece  of  fillet,  and  weighs  it  in  a  delicate 
balance  placed  close  beside  him.    The  fillet  is  placed  on  the  bolster  a,  and  the  trier,  holding 

454 


it  in  the  left  hand,  takes  the  handle  c  in 
his  right,  and  by  pulling  it  towards  him 
causes  the  screw  with  which  it  is  pro- 
vided to  depress  the  cutter  b,  which,  as 
it  travels,  cuts  a  blank  and  pushes  it 
through  A,  the  trier  at  the  same  mo- 
ment placing  his  hand  under  the  bench 
to  catch  the  blank  as  it  falls.  The  spring 
D  is  so  powerful  as  to  carry  back  the 
handle  to  its  original  position  while  the 
trier  is  catching  the  falling  blank.  The 
trier  has  the  most  important  office  in  the 
Mint,  and  it  requires  a  man  with  forti- 
tude and  a  very  calm  judgment ;  for  al- 
though he  places  the  blanks  in  the  scale 
pan,  and  goes  through  the  operation  of 
weighing  it,  he  cannot  of  course  spare 
time  to  see  the  exact  weight ;  he  therefore 
forms  an  opinion  of  the  weight,  and  so  accurate  is  this  opinion  that  he  is  never  known  to 
produce  sovereign  blanks  which  vary  more  than  one  grain  if  forty-seven  are  weighed  at  the 
same  time  at  any  time  of  the  day.  The  result  of  more  than  thirty  tons  of  gold  coined  lately, 
came  out  within  a  very  small  number  (it  is  believed  8  sovereigns)  of  the  whole  value. 

After  leaving  the  hands  of  the  trier  the  fillets  are  wiped  with  cotton  waste  to  free 
them  from  oil,  which  is  found  necessary  to  prevent  the  friction  of  the  metal  at  the  time  of 
passing  between  the  cylinders,  else  it  happens  that  the  cylinders  get  so  hot  as  to  cause 
the  skimming  off  of  the  surface  of  the  fillet. 

The  fillets  having  been  cleaned,  are  taken  into  the  cutting-out  room,  and  are  there  cut 
by  machinery  into  blanks  and  scissel.  Fig.  455  repres^its  one  of  12  cutting-out  presses. 
It  stands  on  a  firm  bed,  and  the  frame  c  is  made  of  solid  iron  bolted  to  the  bed.  Quite 
independent  of  the  frame  of  the  press,  there  are  a  series  of  iron  supports  which  sustain  a 
strong  iron  ring,  a  part  of  which  is  shown  as  having  a  brass  let  into  it  at  a.  Above  this 
frame  is  a  heavy  fly-wheel  laid  horizontally  ;  between  this  fly-wheel  and  tlie  ring  or  frame 
is  a  wheel  driven  on  the  same  .shaft  as  the  fly-wheel,  providecl  with  a  scries  of  cams  or  pro- 
tiuding  parts.  As  the  wheel  revolves  the  cams  strike  the  wheel  f  at  the  end  of  the  lever 
n.     The  lever  n  at  its  middle  is  fixed  to  an  upright  spindle  which  passes  through  the  brass 


766  MINT. 

A,  and  through  the  frame  c,  where  it  is  provided  with  a  screw  terminating  in  a  socket  n,  by 
which  the  twisting  motion  of  the  screw  is  done  away  with.  The  lower  end  of  the  socliet  n 
is  provided  with  a  screw  arrangement  by  which  the  cutter  can  at  convenience  be  fixed  or 
removed.  At  q  there  is  an  arrangement  by  which  the  screw  e,  and  consequently  the  socket 
N,  with  its  cutter,  can  be  brouglit  nearer  to  or  farther  from  the  bolster  whicli  is  held  in  a 
steel  ring  secured  to  the  solid  base  of  the  press  by  the  screws  c,  d. 

When  the  press  is  set  in  motion  by  the  striking  of  the  cam  against  r,  the  cutter  is 
raised  from  the  bolster.  To  bring  the  cutter  down  again,  there  is  an  arrangement  by  which 
a  rod  is  attached  to  the  ring  h,  and  terminates  in  a  system  of  levers  which  lift  a  piston  fit- 
ting in  a  cylinder  hermetically  closed  (but  not  shown  in  the  figure) ;  if,  therefore,  the 
piston  be  raised,  a  vacuum  is  formed  by  which  means  the  atmosphere  becomes  the  weight 
by  which  the  cutter  is  driven  down.  The  cutter-out  is  so  fixed  that  when  it  comes  down  it 
just  enters  the  bolster  sufficiently  to  cause  the  cutting  out  of  the  blank  with  a  clean  edge. 
AVhen  required  for  work,  the  fillet  is  placed  on  the  bolster,  and  the  workman  by  his  foot 
touches  a  treadle  which  releases  the  lever  d  at  g,  and  allows  the  cutter  to  come  do\\Ti  and 
punch  out  a  blank,  which  falls  into  a  box  below  the  bolster,  while  the  fillet  from  which  the 
blank  has  been  punched  or  cut  travels  up  till  it  reaches  the  guard  supported  by  the  screws 
a,  6,  which  detaches  it  from  the  cutter.  At  the  end  of  the  lever  p  is  an  arrangement  sup- 
porting B,  a  block  cut  wedge-shaped,  which  travels  in  a  circular  direction,  tiie  distance  to 
which  it  reaches  being  regulated  by  the  screw  shown  near  to  p.  r  is  a  spring  made  of 
wood  and  cut  with  a  slit,  into  which  b  passes  just  at  the  time  that  the  blank  is  punched  out, 
when  the  spring  gives  the  reverse  motion,  a  start  which  prepares  the  machine  for  the  blow 
which  will  follow  by  the  cam  upon  f. 

The  trier  and  the  officer  in  charge  take  samples  of  the  blanks  from  each  cutter  at  fre- 
quent intervals  and  test  them  in  bulk  against  a  standard  weight,  and  if  the  blanks  exceed 
or  fall  short  of  this  standard,  he  makes  such  alterations  of  the  machinery  as  are  necessary, 
the  object  being  to  produce  blanks  which  are  as  nearly  as  possible  standard  in  weight,  and 
not  to  avail  himself  of  the  "  remedy  "  allowed.  By  the  study  of  this  principle  the  work, 
as  it  is  called,  is  brought  to  the  highest  pei-fection.  The  fillets  from  which  blanks  have 
been  cut  represent  ribbons  punched  full  of  round  lioles,  and  are  now  called  scissel,  which 
is  tied  up  by  a  machine  worked  with  a  rack  and  pinion  in  bundles  of  180  ounces,  and  re- 
turned to  the  melting  house. 

The  blanks  are  turned  out  of  the  boxes  into  bags  and  sent  to  the  weighing  room,  where 
each  blank  is  weighed  by  the  automaton  balance,  and  its  value  is  determined  by  weight 
within  a  certain  limit.     See  Balance. 

The  Automaton  Balance  is  the  most  perfect  piece  of  machinery  yet  invented,  and  owes 
its  origin  entirely  to  Mr.  Wm.  Cotton,  of  the  Bank  of  England  ;  but  it  has  been  adapted  to 
the  purposes  of  the  Mint  by  Messrs.  D.  Kapler  &  Sons,  who  have  carried  its  details  of 
manufacture  to  great  perfection  These  gentlemen  have  adopted  several  improvements 
which  were  proposed  by  Mr.  Pilcher,  who  by  his  practical  use  and  study  of  the  machines 
was  fitted  to  point  out  minute  details  still  wanting  to  complete  the  simplicity  of  the  opera- 
tions to  be  performed  by  the  machines,  that  they  might  give  the  most  accurate  results  iu 
the  shortest  possible  time.  To  give  an  idea  of  the  magnificent  workmanship  of  Messrs. 
Napier,  it  is  only  necessary  to  say,  that  after  seven  years'  daily  work,  the  most  delicate  parts 
of  the  balances  are  still  as  perfect  as  when  first  delivered  from  their  manufactory.  For  the 
ordinary  purposes  of  life,  the  pans  of  a  pair  of  scales  are  suspended  from  the  opposite  ends 
of  the  beam  ;  but  if,  as  is  the  case  in  Mr.  Cotton's  balances,  the  centres  of  action  are  on  a 
line  with  the  centre  of  gravity,  it  does  not  matter  at  what  place  the  pans  are  placed  so  that 
they  are  exactly  equi-distant  from  the  fulcrum  or  centre  knife-edge  of  the  beam  -,  therefore, 
in  fiffx.  456,  457,  458,  the  beam  a  will  be  seen  to  rest  on  its  centre  knife-edge  b,  while  at 
the  extreme  ends  of  tlie  beam  the  knife-edges  c  are  facing  upwards.  The  beam,  which  is 
of  the  most  exquisite  workmanship,  is  cut  from  a  solid  piece  of  hardened  steel.  On  the 
inverted  knife-edges  c,  rest  planes  of  hard  steel  which  support  the  pendant  rods  d  e.  The 
plane  which  supports  the  rod  d  is  surmounted  by  a  disc  of  polished  steel  f,  which  forms  the 
pan  upon  which  the  iilank  or  coin  to  be  weighed  is  placed  by  the  automaton  band  presently 
to  be  described.  Tli«  rod  e  is  provided  at  its  lower  extremity  with  a  cage  g,  in  which  is 
placed  the  counterpoise  or  weight,  which  has  to  be  balailced  with  the  blank  placed  on  the 
pan  or  disc  of  steel  f.  The  rod  e  terminates  in  a  stirrup  ii,  which  passes  quite  freely 
through  a  stand  i,  supported  on  delicate  micrometric  screws.  On  the  stand  i  is  placed  a 
small  weight,  made  of  platinum  wire,  which  rests  on  the  stand  i,  after  liaving  been  passed 
through  the  stirrups  ii.-  The  stan3  i  is  then  regulated  by  its  micrometric  screws  until  the 
weight  of  platinum  wire  just  touches  the  upper  surface  of  the  stirrup,  so  that  there  may  be 
no  blow  given  when  the  stirrup  is  not  in  motion  by  the  beam.  When  the  machine  is  set  in 
motion  by  the  driving  wheels  J,  the  cam  k  forces  forward  the  lever  l,  which  moves  on  pins 
passed  through  blocks  fixed  to  the  table  or  base  of  the  machine.  At  the  upper  end  of  the 
lever  i.  is  a  provision  by  which  it  forces  forward  an  automaton  hand  or  shovel,  the  end  of 
which  is  cut  into  a  semi-circle,  and  is  flattened,  that  it  may  pass  under  a  gauge  into  a  space 


MINT. 


767 


or  hopper  M,  which  is  continued  to  the  height  of  about  two  feet,  and  passes  at  an  angle  of 
about  30"  over  the  top  of  the  machine.     When  the  automaton  hand  is  forced  forward,  the 

456 


blanks  to  be  weighed  are  placed  in  the  hopper  or  shute  m,  and  the  bottom  blank  rests  on 
the  flattened  portion       the  hand,  but  as  the  cam  k  a  forces  back  the  hand  or  shovel  by  the 

457 


468 


768  MINT. 

lever  l,  while  at  the  same  instant  the  forceps  Q,  presently  described,  release  the  rod  d,  the 
bottom  blank  tails  to  the  next  support,  and  rests  there  until  the  hand  or  shovel  returns, 
■when  it  is  pushed  on  to  the  disc  f,  which  is  unable  to  move,  because  the  perpendicular  rod 
s,  which  is  provided  at  its  lower  extremity  with  a  horizontal  rod,  the  ends  of  which  pass 
through  a  notch  or  slit  cut  into  the  rods  n  t,  shown  between  g  and  ii  on  the  rod  k  and  on 
the  corresponding  point  of  the  rod  d.  At  the  moment  that  the  blank  has  been  placed  on 
the  disc  f,  the  cam  o  lifts  the  rod  x  and  sets  the  rods  d  e  at  liberty,  thus  enabling  the  beam 
A  to  assume  the  position  which  it  should  occupy  to  indicate  the  weiglit  of  the  blank  placed 
on  F.  The  weight  having  been  determined,  the  motion  continues,  when  the  cam  p  by  a 
lever  p  closes  a  pair  of  forceps  q,  which  secure  the  rod  d,  while  the  cam  r  allows  the  indi- 
cating finger  s  to  carry  down  the  indicator  t  until  the  indicating  finger  s  touches  a  point 
provided  for  it  in  the  rod  o.  t  is  balanced  so  that  its  finger  has  a  continual  inclination  to 
rise,  and  is  of  service  to  detennine  the  compartment  into  which  the  blank  shall  fall  when  it 
is  weighed  and  pushed  off  by  the  next  bl.ank.  The  blank  falls  into  and  through  a  shute  u, 
the  lower  end  of  which  just  reaches  to  three  openings  on  the  table  on  which  the  machine 
stands ;  but  at  v  it  is  provided  with  three  inverted  steps,  one  of  which  steps  falls  on  to  the 
indicating  finger  t,  when  the  shute  is  forced  outwards  by  the  cam  vr. 

In  use  the  machines  weigh  to  the  001  of  a  grain  with  certainty,  and  at  the  rate  of  23 
blanks  per  minute.  There  are  12  machines  driven  from  a  shaft  common  to  all  the  machines 
by  a  small  atmospheric  engine  ;  but  there  is  attached  to  each  machine  at  the  point  where 
the  pulley  is  connected  with  the  driving  wheels  j,  an  arrangement  by  which  the  machine 
throws  itself  out  of  motion  immediately  should  any  cause  arise  which  would  injure  or  dis- 
arrange the  works. 

The  standard  weight  of  a  sovereign  is  123"2'74  grains ;  but  the  Mint  is  allowed  to  issue 
sovereigns  which  exceed  and  fall  short  of  tliis  weight  to  the  extent  of  0'2568  grain,  which 
is  called  t/ie  remed'j,  and  is  allowed  because,  as  befoie  stated,  it  is  impossible  to  produce 
coins  weighing  exactly  equal. 

Mr.  Pilcher  suggested,  that  since  it  is  necessary  to  determine  the  weights  on  both  sides 
of  the  standard,  it  would  be  easy  to  do  this  without  providing  the  beam  with  two  remedy 
weights,  as  was  originally  done.  The  plan  now  adopted  is  to  reduce  the  weight  used  in  the 
cage  G  to  123'0172  grains,  which  enables  the  blanks  as  heavy  as  this  weight  to  pass;  but 
all  which  will  raise  this  weight,  and  yet  are  not  sufiieiently  heavy  to  raise  with  it  the  weight 
of  platinum  wire  placed  through  the  stirrups  h,  and  resting  on  the  stand  i,  are  known  to  be 
within  the  weight  of  the  given  remedy.  Blanks  which  are  too  light  allow  the  weight  in  G 
to  carry  the  disc  r  upwards,  and  the  forceps  q,  fixing  the  point  to  which  the  indicating  finger 
will  allow  the  shute  to  settle,  the  blank  is  pushed  off  by  its  follower  and  falls  into  the  shute, 
which  conducts  it  into  the  compartment  reserved  for  light  blanks.  Blanks  which  are  so 
heavy  as  to  lift  the  weight  in  g  and  the  remedy  weight,  carry  the  disc  f  downwards,  and 
they  are  consequently  sent  into  the  compartment  reserved  for  heavy  blanks.  Blanks  which 
are  not  standard,  but  which  are  nevertheless  within  the  latitude  of  remedy,  are  called  me- 
dium, and  pass  on  to  be  coined. 

The  three  denominations  of  blanks  are  frequently  tested  by  a  delicate  hand  balance,  to 
see  that  the  automaton  balances  are  performing  their  work  properly ;  but  in  seven  years  no 
instance  of  failure  has  been  detected. 

Each  machine  stands  on  a  planed  iron  table,  and  is  enclosed  by  glass  sides,  which  fit 
down  grooves  cut  in  the  brass  pillars  which  support  the  roof  of  the  machine.  The  roof  is 
made  of  brass,  and  supports  all  the  important  parts  of  the  machinery. 

Thus  a  standard  coin  should  weigh  123'274  grains  to  be  intrinsically  worth  a  sovereign 
in  value  ;  but  since  the  machinery  is  not  capable  of  producing  two  coins  in  a  million  of  this 
exact  weight,  a  certain  limit  or  remedy  is  allowed,  and  in  manufacture  the  coin  may  exceed 
or  fall  short  of  the  standard  weight  to  the  extent  of  0-2568  grain.  All  blanks  that  come 
within  this  limit  on  either  side  of  the  standard  are  called  medium,  and  presently  pass  on  to 
be  coined,  but  those  which  exceed  these  limits  are  termed  light  and  heavy  rejected  ;  and 
if  the  work  of  the  trier  has  been  well  performed,  these  two  species  of  rejected  are  equal  in 
weight,  and  the  medium  if  weighed  in  bulk  would  be  found  to  be  within  a  few  pieces  of  the 
standard  weight  if  a  million  were  weighed  in  bulk  and  then  counted.  It  is  the  weighing 
room  which  determines  the  value  of  the  trier's  work.  The  light  blanks  arc  returned  to  the 
melting  house,  but  the  heavy  blanks  are  reduced  to  the  medium  weight  by  a  filing  machine 
recently  invented  by  Mr.  Pilcher,  the  officer  in  charge  of  this  room,  and  which  was  made 
by  Mr.  Jones  in  the  Mint,  under  Mr.  Pilcher's  directions.  Fig.  459  shows  this  machine. 
E  is  a  hopper  made  of  brass,  and  indicated  by  the  dotted  lines ;  it  serves  to  prevent  the 
scattering  of  the  gold  dust  by  the  rapid  motion  of  the  file,  b  is  a  tube  with  a  slit  cut  in  its 
upper  and  in  its  lower  half;  a  is  a  circular  file  which  is  made  to  revolve  very  rapidly ;  c  is 
a  knife-edge  which  offers  resistance  to  the  circulating  blanks  when  in  motion  ;  d  is  a  glass 
dish  into  which  the  gold  dust  as  it  is  filed  from  the  blanks  falls.  The  blanks  are  arranged 
en  rouleaux  in  a  long  scoop,  by  which  they  are  placed  in  the  tube  b.  The  screws  g  are 
then  depressed  upon  pieces  of  ebony,  previously  passed  into  b,  until  they  just  touch  the 


MINT. 


r69 


blanks  (as  shown  by  the  dotted  lines  in  b.)  The  knife-edge  c,  whose  weight  has  been  pre- 
viously adjusted  by  the  weight  f,  is  now  allowed  to  descend  on  to  the  blanks  and  carry  them 
down  partly  through  the  tube  on  to  the  file.     When  the  file  is  set  in  motion  the  friction 


r 


ii^ 


^ 


460 


gives  to  the  blanks  a  revolving  motion,  which  is  greatly  restrained  by  the  weighted  knife- 
edge  resting  on  the  top  of  the  blanks,  and  the  resistance  offered  causes  the  file  to  cut  the 
gold  away,  while  the  motion  of  the  blanks  insures  the  non-interference  with  their  already 
perfectly  circular  form,  and  the  perfect  separation  of  the  dust  from  the  blanks.  1,400 
blanks  are  reduced  in  one  minute ;  and  as  the  dust  is  carefully  collected,  loss  is  unknown. 

The  medium  blank.-?  are  carefully  rung  by  being  thrown  one  by  one  with  some  force  upon 
a  block  of  iron,  and  those  which  do  not  yield  a  musical  sound  are  called  dumb,  and  are  re- 
turned with  the  light  rejected  and  dust  to  the  melting  house.  About  2  per  cent,  is  the  aver- 
age yield  from  all  causes,  therefore  98  out  of  every  lt)0  blank  struck  out  in  the  cutting 
room  ultimately  become  coined  money. 

The  medium  blanks  which  are  now  determined'  to  be  of  the  legal  weight  and  sound  are 
forwarded  to  the  marking  room,  where  they  are  made  to  undergo  a  peculiar  pressure,  which 
is  necessary  to  raise  the  edge  of  the  blank 
preparatory  to  its  receiving  the  milled  edge, 
because  it  is  found  in  practice,  that  unless  the 
edge  is  prepared,  the  milling  of  the  edge  is 
not  so  perfectly  effected  as  is  required  for  the 
protection  of  the  public  or  the  appearance 
and  good  wearing  of  the  coin. 

The  machine  in  use  at  the  Mint  has  an- 
swered its  purpose  for  many  years,  but  it  is 
peculiarly  liable  to  gpt  out  of  order,  and  as  it 
is  probable  that  it  may  be  replaced,  it  is 
thought  wise  to  give  a  description  of  the  best 
machine  for  this  purpose,  which  was  invented 
by  Messrs.  Ralph  Heaton  &  Sons,  of  Birming- 
ham, and  is  now  most  successfully  used  by 
them.  Fifjs.  4(50,  461,  are  views  of  this 
marking  machine ;  a  a  is  an  iron  frame  in 
wliich  is  a  horizontal  shaft  carrying  a  driving 
and  a  loose  pulley  and  a  fly-wheel ;  n  is  a  flat 
circular  plate  with  a  groove  turned  in  the 
edge  Fixed  to  the  frame  a  is  a  plate  c,  with 
a  groove  cut  in  its  inner  edge  corresponding 
to  the  groove  in  the  plate  b.     The  plate  c  is 


adjusted  to  b  by  the  .screws  n  ;  e  is  a  hopper  into  which  the  blanks  to  be  marked  are  put ; 
F  is  a  circular  plate  on  which  are  a  scries  of  cams,  which,  as  they  revolve,  push  back  the 
feeder  o,  and  so  allow  the  blanks  to  fall  from  the  hopper  k.     The  spring  ii  then  brings  down 
Vol.  III.— 49 


770 


MINT. 


\ :  i' 


the  feeder  g,  which  pushes  a  blank  from  the  bottom  of  the  hopper.  The  blanks  fall  down 
an  inclined  plane  until  their  edges  come  between  the  steel  plates  b  and  c.  The  circular 
plate  B  revolves,  and  the  pressure  of  its  edge  against  the  blanks  carries  them  forward,  and 
at  the  same  time  raises  their  ed^es  all  round  to  about  one-third  increased  thickness.     The 

parts    of   this    machine    are 
'**^^  made  very  rigid,  because  the 

blanks  as  they  leave  the 
machine  must  be  perfectly 
round,  or  they  will  not  pass 
freely  through  the  collar  in 
the  subsequent  process  of 
coining.  The  marking  ma- 
chine of  Messrs.  Heaton 
marks  400  blanks  per  min- 
ute. 

The  blanks  after  having 
been  marked  are  forwarded 
to  the  annealing  room  to  be 
softened  by  heat,  because 
they  have  become,  by  the 
processes  of  manufacture,  so 
hard  that  unless  annealed  and 
softened  (it  is  thought)  they 
would  break  the  dies  rather 
than  receive  the  impression 

_^ from  them.     The  blanks  are 

placed  en  rouleaux  in  iron 
trays.  Each  tray  holds  2,804  blanks ;  and  when  the  tray  is  filled  the  blanks  are  covered  by 
an  iron  plate,  which  is  carefully  luted  down  with  clay  and  then  covered  with  another  iron 
plate  which  is  also  luted  down.  The  tray  is  then  placed  on  a  cast-iron  carriage  and  run 
into  the  annealing  furnace,  which  is  in  every  respect  similar  to  the  furnace  shown  by  fg. 
443  in  the  rolling  room.  The  annealing  pans  full  of  blanks  are  left  in  the  furnace  until 
they  have  sustained  a  full  red  heat  for  20  minutes,  and  are  then  withdrawn  and  placed  on 
the  floor  until  the  iron  pan  has  lost  its  red  heat,  when  the  tops  are  removed  and  the  blanks 
are  turned  out  into  a  copper  pan  and  carried  to  the  blanching  room,  where  they  are  thrown 
into  a  colander  in  cold  water,  that  they  may  be  softened  by  the  rapid  cooling.  They  are  then 
lifted  in  the  colander  into  a  leaden  boiler  of  boiling  sulphuric  acid  diluted  with  9  parts  of 
water.  They  remain  in  this  bath  of  diluted  sulphuric  acid  for  a  few  minutes,  until  the  sur- 
face of  the  blanks  has  become  bright  and  free  from  the  black  oxide  of  copper  which  has 
been  formed  in  the  course  of  the  process  of  annealing.  At  the  time  of  melting  a  fixed 
amount  of  copper  is  added  in  addition  to  the  amount  of  copper  which  is  used  to  bring  the 
gold  to  the  standard,  and  this  copper,  which  is  called  extra  alloy,  is  the  exact  amount  which 
is  removed  from  the  surface  of  the  blanks  (forming  sulphate  of  copper)  by  the  process  of 
blanching  in  dilute  sulphuric  acid  ;  but,  as  will  be  readily  understood,  if  we  remove  copper 
from  the  surface  by  dissolving  it  out  from  an  alloy  of  gold  and  copper,  the  gold  which  re- 
mains on  the  surface  must  be  in  a  honey-comb  or  spongy  condition,  and  this  thin  surface 
of  spongy  gold  gives  to  the  coin  when  struck  the  beautiful  bloom  which  is  observed  on  new 
coin.  In  the  case  of  some  peculiar  gold,  the  process  of  annealing  the  blanks  was  omitted  ; 
and  it  is  probable  that  this  process  may  ultimately  be  wholly  abolished.  After  blanching, 
the  blanks  are  freely  washed  with  cold  water  to  remove  all  the  sulphate  of  copper  from  their 
surfaces,  and  after  washing  they  are  dried  by  rubbing  in  a  bath  of  hot  box-wood  sawdust, 
which  absorbs  the  wet  just  as  a  sponge  would  ;  and  as  the  sawdust  is  thrown  upon  hot  iron 
plates  it  soon  again  becomes  dry,  and  is  then  ready  for  the  next  set  of  blanks.  It  is  found 
that  sawdust  will  not  remove  the  last  trace  of  moisture  which  evidently  lurks  in  the  sub- 
stance of  the  spongy  surface  of  gold,  the  blanks  are  therefore  thrown  into  a  revolving  cop- 
per colander,  which  fits  into  a  kind  of  oven,  heated  to  a  temperature  rather  higher  than 
boiling  water.  They  are  shaken  in  this  heated  atmosphere  for  about  10  minutes,  and  are 
then  perfectly  dry.  It  is  necessary  that  the  blanks  should  be  absolutely  dry  before  going 
to  the  coining  room,  else  they  not  only  make  dirty  coin,  but  spoil  the  dies  by  destroying  the 
polish  on  their  surface. 

Tlie  blanks,  after  leaving  the  hot-air  bath  just  described,  are  taken  into  the  press  room 
to  receive  the  impression  which  renders  them  the  coin  of  the  realm.  Next  to  the  weighing 
machines,  invented  by  Mr.  Cotton,  the  coining  press  is  the  most  beautiful  piece  of  mechan- 
ism in  the  Mint.  It  is  automaton,  and  does  all  that  is  required  of  it  without  the  aid  of  man, 
and  it  may  even  be  said  to  talk,  for  it  is  the  most  noisy  of  all  the  Mint  machinery.  When 
the  eight  presses  are  at  work,  it  is  quite  hopeless  to  hear  a  word  spoken.  Fif).  462  is  a 
representation  of  one  of  these  presses.     It  stands  on  a  solid  bed  of  masonry,  and  is  firmly 


MINT. 


771 


bolted  down.  The  massive  frame-work  c  is  made  of  cast  iron,  and  is  perforated  from  the 
top  to  admit  of  the  passage  of  a  powerful  screw  which  is  represented  by  d  as  travelhng 
through  the  solid  mass,  d  is  continued  upwards  through  the  ceiling  of  the  room  by  a  rod 
of  iron  which  is  enclosed  by  a  trumpet-shaped  case  of  iron,  represented  by  a.     At  the  top 

462 


of  A  is  fitted  a  lever,  which  drives  the  press  by  the  agency  of  the  air-pump.  The  iron  rod 
which  continues  from  d  through  a,  passes  freely  through  an  eye-hole  in  the  lever  of  a,  and 
is  then  provided  with  a  swivel  joint,  which  terminates  its  horizontal  motion,  while  the  rod 
which  carries  the  swivel  joint  is  attached  to  a  long  lever,  the  farther  end  of  which  is  con- 
nected with  a  piston  whrking  in  a  partly  exhausted  cylinder,  so  that  when  n  is  forced  down 
by  the  action  of  the  air-pump,  it  of  necessity  lifts  this  piston  from  the  bottom  of  its  cylin- 
der, thereby  causing  a  partial  vacuum  ;  the  atmosphere  tlien  pressing  on  the  piston  over- 
balances the  weight  of  n,  and  returns  it  to  its  position,  that  its  lever  may  iigaiii  come  under 
the  influence  of  the  air-pimip.  On  tlie  bars  r  are  fitted  blocks  of  iron,  wood,  wood  lined 
with  iron,  or  iron  lined  with  wood,  according  to  the  force  of  blow  rcfpiircd  to  be  given. 
These  blocks  sim|)ly  answer  the  purpose  of  a  fly-wheel,  but  striking  against  a  bufler  at  the 


772 


MINT. 


moment  that  the  dies  have  exerted  sufficient  force  on  the  blanks,  they  prevent  the  destruc- 
tion of  tlie  dies,  and  give  the  press  a  start  back  again  to  its  original  position.  At  7  is  fixed 
on  I)  a  piece  of  brass  of  an  eccentric  form,  which  would  be  best  understood  if  it  were  de- 
scribed as  of  the  shape  a  shilling  would  assume  if  it  were  pierced  at  the  point  which  is  sup- 
posed to  represent  the  nose  of  her  Majesty,  and  a  slit  were  then  cut  in  the  place  of  the  in- 
scription at  tlie  back  of  the  head  of  tlie  same  figure,  extending  from  the  a  of  gratia  to  the 
I)  of  the  F.  D.  In  the  slit  so  described  the  lever  ii  travels,  but  as  it  is  fixed  on  a  pivot  at  1, 
that  part  which  travels  tlirough  the  slit  becomes  the  short  end  of  the  lever,  and  in  conse- 
quence that  part  which  is  below  1  is  the  longest ;  therefore,  when  v  descends  with  its  circu- 
lar motion,  it  also  gives  the  eccentric  brass  plate  7  a  twirl  and  throws  the  long  end  of  the 
lever  through  a  considerable  proportionate  distance.  At  the  lower  end  of  the  lever  at  l,  is 
a  brass  frame  which  carries  an  automaton  hand  through  the  slide  8.  "When  the  automaton 
hand  is  set  in  motion,  it  carries  a  blank  from  the  lower  end  of  the  tube  k  and  deposits  it  in 
the  collar  which  fits  over  the  lower  die,  and  returns  to  fetch  another  blank  while  the  upper 
die  descends  to  coin  the  blank  just  deposited,  d  receives  a  motion  which  carries  it  through 
half  a  circle  ;  but  if  this  twisting  motion  were  given  to  the  mppcr  die,  it  would  render  the 
coin  to  be  produced  imperfect,  therefore  the  strong  rods  e  travel  through  the  main  frame  C, 
and  at  their  lower  ends  are  provided  with  brasses,  the  outer  surfaces  of  which  are  grooved 
to  fit  the  wedge  shape  into  which  c  is  cut  at  this  point.  The  rods  e  are  fixed  to  n  and 
travel  with  it,  carrying  at  f  an  arrangement  by  which  the  block  4  is  prevented  from  twist- 
ing round,  i)  fits  into  a  socket  provided  with  a  brass  at  3.  The  lower  die  is  fixed  in  a 
block  5,  provided  with  adjusting  screws,  and  resting  on  the  base  6.  The  upper  die  is  fixed 
in  the  block  4,  which,  in  fact,  becomes  literally  a  part  of  n.  When  the  press  is  in  down- 
ward motion,  the  springs  resting  on  the  block  5  lift  the  milled  collar  which  fits  over"the 
neck  of  the  lower  die,  and  causes  it  to  enclose  the  blocks  already  placed  there  while  the 
blow  is  given  ;  but  directly  the  press  starts  on  its  upward  journey,  the  rod  e  catches  a  small 
lever  g  and  forces  the  collar  down  on  to  the  shoulder  of  the  lower  die,  while  the  automaton 
hand  comes  forward  and  displaces  the  coin,  while  it  places  another  blank  on  the  die  ready 
for  the  next  blow  of  the  press. 

Ficf.  463  gives  a  view  of  the  milled  collar  a.     d  being  a  representation  of  the  lower  die, 
with  its  long  neck  which  fits  nicely  into  the  milled  collar  a.     c,  the  upper  die,  also  passes 

to  a  small  distance  into  the  collar,  so 
463  that  at  the  moment  of  the  blow  the 

blank  is  absolutely  enclosed.  The 
blow,  which  is  estimated  at  40  tons, 
forces  the  metal  into  every  engraved 
part  of  the  collar  and  dies.  The 
press,  which  has  been  described  with 
as  few  technical  terms  as  possible, 
coins  from  60  to  80  blanks  per  min- 
ute, finishing  by  one  blow  the  obverse 
and  reverse  impressions,  and  adding 
the  milled  edge.  (For  the  manufac- 
ture of  dies,  see  Dies.) 

The  coins  when  struck  are  col- 
lected at  frequent  intervals  and  care- 
fully overlooked  to  find  any  which 
may  be  defective ;  for,  with  all  the 
beauty  of  the  mechanism  of  the  press, 
accidents  cannot  be  avoided,  and  it  is 
found  that  about  one  coin  in  200  is 
imperfect  in  its  finish,  whatever  its 
size  or  value.  The  imperfect  coins 
are  returned  with  the  ends  cut  from 
the  bars,  the  scissel,  and  the  imperfect 
and  out-of-reniedy  blanks  to  the  melt- 
ing house  every  morning  The  coins 
are  weighed  into  bags,  each  containing  70'!  sovereigns,  and  at  intervals,  depending  on  the 
requirements  of  the  Bank,  sent  to  the  Mint  office,  where  they  undergo  that  time-honored 
process  of  the  Pyx,  which  means  that  the  sovereigns  are  weighed  out  into  pounds  Troy,  and 
their  difference  plus  or  minus  upon  the  standard  weight  is  noted,  two  pieces  being  taken 
from  each  bag.  One  of  these  two  is  placed  in  a  strong  box  and  reserved  for  the  "  trial  of 
the  Pyx"  at  Westminster  Hall,  and  the  other  is  divided,  and  sent  to  the  non-resident  assay- 
ers,  who  report  upon  its  purity.  The  coins  which  are  taken  are  not  selected,  but  culled 
indiscriminately  from  the  bagfull.  After  assaying  (unless  the  assay  should  be  unsatisfac- 
tory) notice  is  sent  to  the  Bank  of  England,  and  at  a  fixed  time  an  officer  comes  with  a 
wagon  and  two  porters  and  fetches  the  gold  coin. 


MOHAIR.  ns 

It  is  only  necessary  to  repeat  that  silver  and  gold  undergo  precisely  similar  treatment, 
but  it  has  been  omitted  to  say  that  the  bars  for  different  denominations  of  coin  are  of  dif- 
ferent widths,  but  all  of  the  same  length  and  thicliness  as  regards  silver. 

Notwithstanding  the  inference  implied  by  the  company  of  moncyers,  and  the  evidence 
to  be  found  in  Blue  Books,  it  is  untrue  to  state  that  there  nmst  be  a  loss  by  coining  the  pre- 
cious metals.  At  this  present  time  loss  in  the  coining  department  is  utterly  unknown,  and 
this  cannot  be  surprising  if  the  great  chemical  fact  that  "  matter  cannot  be  lost"  be  kept  in 
mind  ;  for,  however  much  we  may  divide  a  substance,  the  aggregate  of  its  pieces  must  again 
make  up  the  total  ;  so  it  is  with  minting,  and  tlie  minute  particles  which  escape  the  watch- 
ful eyes  of  the  workmen  and  their  officers  are  recovtn'cd  in  the  dust  and  sweepings  of  tlie 
Mint.  In  the  process  of  melting,  there  is  an  apparent  loss  to  a  small  extent,  but  this  is 
nearly  balanced  by  the  money  obtained  for  the  sweepings. 

When  it  is  stated  that  there  is  no  loss  by  coining,  it  must  not  be  understood  that  the 
coining  department  receives  a  definite  weight  of  bars,  and  returns  an  exactly  equivalent 
weight  of  coin  ;  as  tiiis  is  not  intended  to  be  stated  ;  for  it  is  evident  that  the  extra  alloy 
which  is  added,  that  it  may  be  removed  by  the  process  of  blanching  or  pickling,  must  be 
taken  into  account,  as  also  must  the  value  of  the  sweepings.  But  it  is  distinctly  stated, 
that  if  to  the  coin  delivered,  the  calculated  amount  of  extra  alloy  and  the  value  of  the 
sweep  be  added,  there  is  then  no  loss  Ijy  coining,  although  a  small  margin  must  be  allowed 
for  minute  differences  in  weighing  between  the  different  departments.  This  is  positively 
true  as  regards  gold,  but  there  are  some  elements. of  calculation  which  are  omitted,  and 
make  it  appear  tliat  there  is  a  very  trifling  loss  in  ceining  silver ;  it  is  nevertheless  probable 
that  some  of  the  silver  is  volatilized  by  the  many  annealings  it  is  submitted  to,  and  its  bulk 
probably  gives  a  greater  latitude  for  differences  of  weighing.  It  has  long  been  observed, 
that  when  gold  coins,  which  have  circulated  till  they  have  become  "  light,"  are  melted  and 
assayed,  the  ingots  are  almost  invaria))ly  below  the  standard  of  fineness  This  has  been 
attributed  to  the  introduction  of  base  coins  ;  but  it  seems  to  Ije  more  probably  owing  to  the 
removal  of  the  surface  of  pure  gold,  which  is  left  at  the  time  of  blanching,  by  the  wear  to 
which  the  coins  are  subjected  in  circulation. 

It  must  be  borne  in  mind,  that  the  foregoing  is  not  intended  for  a  descriptive  account 
of  the  Mint  machinery,  but  simply  as  a  faithful  relation  of  the  processes  adopted  to  convert 
bullion  into  coin — minting  as  it  is  at  this  date,  1859. — G.  F.  A. 

MOHAIR  is  the  hair  of  a  goat  which  inhabits  the  mountains  in  the  vicinity  of  Angora, 
in  Asia  Minor. 

We  are  indebted  for  this  account  of  mohair  to  the  History  of  the  Worsted  Manufacture 
of  England,  by  James. 

Very  much  akin  to,  and  in  Yorkshire  rising  into  importance  about  the  same  time  as 
that  of  alpaca,  the  mohair  manufacture  demands  attention. 

The  goat  is  amongst  the  earliest  animals  domesticated  by  man,  and  undoubtedly,  from 
the  very  earliest  ages,  the  fabrication  of  stuffs  from  its  hair  was  practised  by  the  nations  of 
antiquity.  Throughout  the  middle  ages  the -art  of  making  beautiful  stuffs  from  the  cover- 
ing of  the  goat  prevailed. 

After  the  Angora  goats  have  completed  their  first  year,  they  are  clipped  annually,  in 
April  and  May,  and  yield  progressively  from  one  to  about  four  pounds'  weight  of  hair. 
That  of  the  female  is  considered  better  than  the  male's,  but  both  are  mixed  together  for 
the  market,  with  the  exception  of  the  two-ifear-old  shcr/oafs  fccce ;  which  is  kept  with  the 
picked  hair  of  other  white  goats  (of  which,  perhaps,  5  lbs.  may  be  chosen  out  of  lOOo) 
for  the  native  manufacture  of  the  most  delicate  articles ;  none  being  ever  exported  in  any 
unwrought  state.  Common  hair  sold  in  the  Angora  bazaar  for  9  piastres,  or  about  l.s.  8^(/. 
the  oke  (that  is,  2f  lbs.),  whilst  the  finest  picked  wool  of  the  same  growth  fetched  14  pias- 
tres the  oke.  When  the  fleeces  are  shorn,  the  women  sqiarate  the  clean  hair  from  the 
dirtj',  and  the  latter  only  is  washed.  After  which,  the  whole  is  mixed  together,  and  .sent  to 
the  market.  That  which  is  not  exported  raw  is  l)ought  by  the  women  of  the  laboring  fam- 
ilies, who,  after  pulling  portions  loose  with  their  fingers,  pass  them  successively  through  a 
large  and  fine  toothed  comi),  and  spin  it  into  skeins  of  yarn,  of  which  six  qualities  are 
made.  An  oke  of  Xos.  1  to  3  fetched  in  the  Angora  l)azaar  from  24  to  2.5  ])iastres,  and 
the  like  weight  of  Nos.  3  to  G  from  88  to  40  piastres.  Threads  of  the  fir.-^t  three  Xos.  had 
been  usually  sent  to  France,  Holland,  and  (Jermany  ;  those  of  the  last  three  (pialitics  to  Eng- 
land. The  women  of  Angora  moisten  the  hair  with  much  spittle  before  they  draw  it 
from  the  distaff,  and  they  assert  that  the  quality  of  the  thread  gi-catly  depends  upon  this 
operation. 

Formerly  there  was  a  prohibition  against  the  export  from  Turkey  of  the  Angora  hair 
except  when  wrought,  or  in  the  form  of  homes])un  yarn;  l)ut  nboiit  the  time  of  tiie  (!reek 
revolution,  this  ])rohibition  was  removed,  l^p  to  that  periotl,  however,  there  had  lieen 
little  demand  for  the  raw  material  in  Europe,  so  that  it  sold  in  the  year  1820  at  only  lOi/. 
per  pound  in  England.  The  reason  of  the  raw  material  not  Ijcing  in  re((uest  arose  from 
the  belief  that,  owing  to  the  peculiarity  of  the  fibre,  it  could  not  be  spun  by  machinery. 


774  MOIRE. 

It  soon,  however,  became  apparent  that  mohair  could  be  thus  spun  in  England,  and  this 
was  more  to  be  desired,  because  the  Angora  spun  yarn  had  so  many  imperfections,  from 
being  thick  and  uneven,  as  to  detract  greatly  from  its  value.  This  object,  however,  has  been 
obtained  mainly  by  the  perseverance  of  Mr.  Southey,  the  eminent  London  wool-broker. 
Since  then  the  use  of  the  Angora  m-ooI  has  much  extended,  whilst  the  importation  has 
much  decreased,  the  English  spun  yarn  being  preferred. 

The  demand  for  Angora  hand-spun  yarn  has  almost  ceased,  and  its  value  in  Turkey  has 
fallen  to  one-half.  Mohair  is  transmitted  to  England  chiefly  from  the  ports  of  Smyrna  and 
Constantinople.  In  color  it  is  the  whitest  known  in  the  trade,  and  is  consequently  pecu- 
liarly adapted  for  the  fabrication  of  a  certain  class  of  goods.  Besides  Angora,  quantities 
of  an  inferior  sort  of  mohair  are  received  from  other  parts  of  Asiatic  Turkey — a  very  fine 
description  of  goat's  hair  is  also  sent  from  that  country. 

In  England,  mohair  is  mostly  spun,  and  to  some  extent  manufactured  at  Bradford,  and 
also  in  a  less  degree  spun  at  Norwich.  Scotland  is  also  engaged  in  working  up  mohair 
yarn.  At  first  great  difficulty  occurred  in  sorting  and  preparing  the  material  for  spinning, 
but  by  patient  experiment  this  has  been  efiectuuUy  surmounted,  and  a  fine  and  even  thread 
produced,  fitted  for  the  most  delicate  webs. 

The  price  of  Angora  goats'  hair  has,  since  its  importation  into  this  country,  fluctuated 
very  much,  partly  from  the  variations  in  demand,  and  partly  owing  to  the  supply.  When 
the  wool  was  first  introduced,  it  realized  only  Is.  Sd.  or  Is.  4d.  per  pound.  During  the 
years  1845  and  1846,  it  ranged  from  Is.  Bd.  to  Is.  8d.  per  pound;  and  about  the  year  1850 
it  sold  for  Is.  9d.  to  Is.  lOd.  per  pound ;  and  now  it  is  sold  on  the  average  at  Is.  lOd.  per 
pound. 

Numerous  articles  are  manufactured  from  mohair.  For  instance,  many  kinds  of  cam- 
blets,  which,  when  watered,  exhibit  a  beauty  and  brilliance  of  surface  unapproached  by 
fabrics  made  from  English  wools.  It  is  also  manufactured  into  plush,  as  well  as  for  coach 
and  decorative  laces,  and  also  extensively  for  buttons,  braidings,  and  other  trimmings  for 
gentlemen's  coats.  Besides,  it  is  made  up  into  a  light  and  fashionable  cloth,  suitable  for 
paletots,  and  such  like  coats,  combining  elegance  of  texture  with  the  advantages  of  repelling 
wet.  A  few  years  since,  mohair  striped  and  checked  textures  for  ladies'  dresses,  possessing 
unrivalled  glossiness  of  appearance,  were  in  request :  but  of  late  these  have  been  superseded 
by  alpaca.  For  many  years  the  export  of  English  mohair  yarn  has  been  considerable  to 
France. 

This  trade  is  enjoyed  at  Bradford  and  Norwich,  but  chiefly  by  the  former  place.  This  yarn 
is  manufactured  in  France  into  a  new  kind  of  lace,  which,  in  a  great  measure,  is  substituted 
for  the  costly  fabrics  of  Valenciennes  and  Chantilly.  The  Angora  goats'  hair  lace  is  as  bril- 
liant as  that  made  from  silk,  and  costing  only  about  Is.  2d.  the  piece,  has  come  into  very 
general  wear  among  the  middle  classes.  Mohair  is  also  manufactured  into  fine  shawls,  sell- 
ing from  £4  to  £16  each.  Also  large  quantities  of  what  is  termed  Utrecht  velvet,  suitable 
for  hangings,  and  furniture  linings  for  carriages  are  made  from  it  abroad.  Recently  this 
kind  of  velvet  has  begun  to  be  manufactured  at  Coventry,  and  it  is  fully  anticipated  that 
the  English  made  article  will  successfully  compete  with  the  foreign  one  in  every  essential 
quality. 

MOIRE  is  the  name  given  to  the  best  watered  silks.  These  silks  are  made  in  the  same 
way  as  ordinary  silks,  but  always  much  stouter,  sometimes  weighing,  for  equal  surface, 
several  times  heavier  than  the  best  ordinary  silks.  They  are  always  made  of  double  width, 
and  this  is  indispensable  in  obtaining  the  bold  waterings,  for  these  depend  not  only  on  the 
quality  of  the  silk,  but  greatly  on  the  way  in  which  they  are  folded  when  subjected  to  the 
enormous  pressure  in  watering.  They  .should  be  folded  in  such  a  manner  that  the  air 
which  is  contained  between  the  folds  of  it  should  not  be  able  to  escape  easily ;  then  when 
the  pressure  is  applied  the  air,  in  trying  to  effect  its  escape,  drives  before  it  the  little  moist- 
ure which  is  used,  and  hence  causes  the  watering.  Care  must  also  be  taken  so  to  fold  it 
that  every  thread  may  be  perfectly  parallel,  for  if  they  ride  one  across  the  other,  the  water- 
ing will  be  spoiled.     The  pressure  used  is  from  60  to  100  tons. — H.  K.  B. 

MORPHINE.  ^(/».  Morphia.  {3forphi7ie,  ¥r.  ;  Morphiv,  Germ.)  C'^ir'NO^-f  2  aq. 
An  organic  base,  contained  (amongst  others)  in  opium.  As  it  is  the  substance  upon 
which  the  sedative  properties  of  opium  depend,  great  attention  has  been  paid  to  its  ex- 
traction. Numerous  processes  have  been  devised  for  the  purpose ;  but  perhaps  that  of 
Gregory  is,  in  facility  and  economy,  as  good  as  any.  The  aqueous  infusion  is  precipitated 
by  chloride  of  calcium  to  remove  the  meconic  and  sulphuric  acids  present.  The  filtered 
fluid  is  evaporated  until  the  hydrochlorate  of  morphine  crystallizes  out,  so  as  to  form  a 
nearly  solid  ma.«s,  which  is  then  strongly  pressed  :  the  liquid  exuding  contains  the  coloring 
matters  and  several  alkaloids.  The  pressed  mass  is  crystallized  and  squeezed  repeatedly, 
and,  if  necessary,  bleached  with  animal  charcoal.  The  hydrochlorate,  which  contains  a 
little  codeine,  is  to  be  dissolved  in  water  and  precipitated  by  ammonia ;  pure  morphia  pre- 
cipitates, and  the  codeine  remains  in  solution.  The  salts  of  morphia  most  employed  in 
medicine  are  the  hydrochlorate,  the  acetate,  and  the  sulphate.  A  solution  of  5  grains  of 
morphia  in  1  ounce  of  water  is  about  the  same  strength  as  laudanum.^— C.  C.  W. 


MOSAIC.  775 

MORTAR.     A  mixture  of  lime  with  water  and  sand. 

The  sand  used  in  making  mortar  should  be  sharp — that  is,  angular,  not  round — and 
clean,  that  is,  free  from  all  earthy  matter,  or  other  than  silieious  particles.  Hence  road 
scrapings  always,  as  being  a  mixture  of  sand  and  mud,  and  pit  sand  generally,  as  being 
scarcely  ever  without  a  portion  of  clay,  should  be  washed  before  they  are  used,  which  is 
seldom  necessary  with  rirer  sand,  this  being  cleaned  by  the  flowing  water.  "  1  have  ascer- 
tained by  repeated  experiments,  that  1  cubic  foot  of  well  burned  chalk  lime  fresh  from  the 
kiln,  weighing  35  lbs.,  when  well  mixed  with  SI  cubic  feet  of  good  river  sand,  and  about 
1|  cubic  foot  of  water,  produced  above  3  J  cubic  feet  of  as  good  mortar  as  this  kind  of  lime 
is  capable  of  forming.  A  smaller  proportion  of  sand,  such  as  two  parts  to  one  of  lime,  is, 
however,  often  used,  which  the  workmen  generally  prefer,  but  because  it  requires  less  time 
and  labor  in  mixing,  which  saves  trouble  to  the  laborei-s,  and  it  also  suits  convenience  of 
the  masons  and  bricklayers  better,  being  what  is  termed  tougher,  that  is,  more  easily  work- 
ed, but  it  does  not  by  any  means  make  such  good  mortar.  If  on  the  other  hand  the  sand 
))e  increased  to  more  than  the  above  proportion  of  3^,  it  renders  the  mortar  too  short,  that 
is,  not  plastic  enough  for  use,  and  causes  it  also  to  be  too  friable,  for  excess  of  sand  pre- 
vents mortar  from  setting  into  a  compact  adhesive  mass.  In  short,  there  is  a  certain  just 
proportion,  between  these  two  ingredients  which  produces  the  best  mortar,  which  I  should 
say  ought  not  to  be  less  than  3,  nor  more  than  S^  parts  of  sand,  to  1  of  lime ;  that  is  when 
common  chalk  lime,  or  other  pure  limes  are  used,  for  different  limes  require  different 
proportions.  When  the  proportion  of  sand  to  lime  is  stated  in  the  above  maner,  which  is 
done  by  architects  as  a  part  of  their  specification,  or  general  directions  for  the  execution  of 
a  building,  it  is  always  understood,  when  nothing  is  expressed  to  the  contrary,  that  the 
parts  stated  are  by  fair  level  measure  of  the  lime,  and  by  stricken  measure  for  the  sand  ; 
and  that  the  lime  is  to  be  measured  in  lumps,  in  the  same  state  in  which  it  comes  from  the 
kiln,  without  slaking,  or  even  breaking  it  into  smaller  pieces." — Pasley. 

MOSAIC.  {Mosa'iqne,  Fr. ;  Mosaisch,  Germ.)  There  are  several  kinds  of  mosaic,  but  all 
of  them  consist  in  imbedding  fragments  of  different  colored  substances,  usually  glass  or 
stones,  in  a  cement,  so  as  to  produce  the  effect  of  a  picture.  The  beautiful  chapel  of  Saint 
Lawrence  in  Florence,  which  contains  the  tombs  of  the  Medici,  has  been  greatly  admired 
by  artists,  on  account  of  the  vast  multitude  of  precious  marbles,  jaspers,  agates,  aventurines, 
malachites,  &c.,  applied  in  mosaic  upon  its  walls.  The  detailed  discussion  of  this  subject 
belongs  to  a  treatise  upon  the  fine  arts.  The  progress  of  the  invention  is  so  curious  that 
some  brief  notice  of  mosaic  work  in  general  will  not  be  out  of  place. 

When,  with  his  advancing  intelligence,  man  began  to  construct  ornamental  articles  to 
decorate  his  dwelling,  or  to  adorn  his  person,  we  find  him  taking  natural  productions,  chiefly 
from  the  mineral  kingdom,  and  combining  them  in  such  a  manner  as  will  afford,  by  their 
contrasts  of  color,  the  most  pleasing  effects.  From  this  arose  the  art  of  mosaic,  which  ap- 
pears, in  the  first  instance,  to  have  been  applied  only  to  the  combination  of  dice-shaped 
stones  (tesserce)  in  patterns.  This  was  the  opus  musivum  of  the  Romans ;  improving  upon 
which,  we  have  the  Italians  introducing  the  more  elaborate  and  artistic  pietra  dura,  now 
commonly  known  as  Florentine-work.  It  is  not  our  purpose  to  treat  of  any  of  the  ancient 
forms  of  mosaic-work,  further  than  it  is  necessary  to  illustrate  the  subject  before  us.  The 
opus  tcsselatum  consisted  of  small  cubes  of  marble,  worked  by  hand  into  simple  geometrical 
figures.  The  opus  sectile  was  formed  of  different  crusts  or  slices  of  marble,  of  which  figures 
and  ornaments  were  made.  The  opus  vermiculatum  was  of  a  far  higher  order  than  these  : 
by  the  employment  of  differently-colored  marbles,  and,  where  great  brilliancy  of  tint  was 
required,  by  the  aid  of  gems,  the  artists  produced  imitations  of  figures,  ornaments,  and 
pictures,  the  whole  object  being  portrayed  in  all  its  true  colors  and  shades. 

The  advance  from  the  opus  vermiculatum  to  the  fine  mosaic  work,  which  had  its  origin 
in  Rome,  and  is,  therefore,  especially  termed  Roman  mosaic,  was  easy ;  and  we  find  this 
delicate  manufacture  arising  to  a  high  degree  of  excellence  in  the  city  where  it  originated, 
and  to  which  it  has  been  almost  entirely  confined,  Venice  being  the  only  city  which  has 
attempted  to  compete  with  Rome.  To  this  Art-manufacture  we  more  especially  direct 
attention,  since  a  description  of  it  will  aid  us  in  rendering  intelligible  the  most  interesting 
and  peculiarly  novel  manufacture  of  mosaic  rug-work,  as  practised  by  the  Messrs.  Crosslcys. 
Roman,  and  also  Venetian  enamels,  arc  made  of  small  rods  of  glass,  called  indiscriminately 
paste  and  smalt.  In  the  first  place  cakes  of  glass  are  manufactured  in  every  variety  of  color 
and  shade  that" are  likely  to  be  required.  These  cakes  are  drawn  out  into  rods  more  or  less 
attenuated,  as  they  are  intended  to  be  used  for  finer  or  for  coarser  works,  a  great  number 
being  actually  threads  of  glass.  These  rods  and  threads  are  kept  in  bundles,  and  arranged 
in  sets  corresponding  to  their  colors,  each  division  of  a  set  presenting  every  desired  shade. 
A  piece  of  dark  slate  or  marble  is  prepansd,  by  being  hollowed  out  like  a  box,  and  this  is 
filled  with  plaster  of  Pari.s.  Upon  this  plaster  the  pattern  is  drawn  by  the  artist,  and  the 
mosaicisti  proceeds  with  his  work  by  removing  small  s<iuares  of  the  plaster,  and  filling  in 
these  with  pieces  cut  from  the  rods  of  glass.  Gradually,  in  this  manner,  all  the  i)laster  is 
removed  and  a  picture  is  formed  by  the  end  ofthejilaments  of  colored  glass ;  these  arc 


776  MOSAIC  WOOL  WORK. 

carefully  cemented  together  by  a  kind  of  mastic,  and  polished.  In  this  way  is  formed,  not 
only  those  exquisitely  delicate  mosaics  which  were  at  one  time  very  fashionable  for  ladies' 
brooches,  but  tolerably  large,  and  often  highly  artistic  pictures.  Many  of  our  readers  will 
remember  the  mosaic  landscapes  which  rendered  the  Italian  Court  of  the  Great  Exhibition 
so  attractive ;  and  in  the  Museum  of  Practical  Geology  will  be  found  a  portrait  of  the  late 
Emperor  of  Russia,  which  is  a  remarkably  good  illustration  of  mosaic-work  on  a  large  scale. 
We  may  remark,  in  passing,  that  the  whole  process  of  glass  mosaic  is  well  illustrated  in 
this  collection. 

The  next  description  of  mosaic  work  to  which  we  will  direct  attention  is  the  manufacture 
of  Tunbridge.  The  wood  mosaics  of  Tunbridge  are  formed  of  rods  of  wood,  varying  in 
color,  laid  one  upon  the  other,  and  cemented  together,  so  that  the  pattern,  as  with  the 
glass  mosaics,  is  produced  by  the  ends  of  the  rods. 

MOSAIC  WOOL  WORK.  There  is  no  branch  of  manufacture  which  is  of  a  more  curi- 
ous character  than  the  mosaic  wool  work  of  the  Messrs.  Crossleys  of  Halifax. 

By  referring  to  the  article  Mosaic,  there  will  be  no  difficulty  in  understanding  how  a 
block  of  wood,  which  has  been  constructed  of  hundreds  of  lengths  of  colored  specimens, 
will,  if  cut  transversely,  produce  a  great  number  of  repetitions  of  the  original  design.  Sup- 
pose, when  we  look  at  the  transverse  section  presented  by  the  end  of  a  Tunbridge  block,  we 
see  a  very  accurately  formed  geometric  pattern ;  this  is  rendered  perfectly  smooth,  and  a 
slab  of  wood  is  glued  to  it.  When  the  adhesion  is  secure,  as  in  a  piece  of  veneering  for 
ordinary  cabinet-work,  a  very  thin  slice  is  cut  off  by  means  of  a  circular  saw,  and  then  we 
have  the  pattern  presented  to  us  in  a  state  which  admits  of  its  being  fashioned  into  any 
article  which  may  be  desired  by  the  cabinet-maker.  In  this  way,  from  one  block,  a  very 
large  number  of  slices  can  be  cut  off,  every  one  of  them  presenting  exactly  the  same  design. 
If  lengths  of  worsted  are  substituted  for  those  of  glass  or  of  wood,  it  will  be  evident  that 
the  result  will  be  in  many  respects  similar.  By  a  process  of  this  kind  the  mosaic  rugs — 
with  very  remarkable  copies  from  the  works  of  some  of  our  best  artists — are  produced. 
In  connection  with  this  manufacture,  fa  few  words  on  the  origin  of  this  kind  of  work  will 
not  be  out  of  place. 

The  tapestries  of  France  have  been  long  celebrated  for  the  artistic  excellence  of  the 
designs,  and  for  the  brilliancy  and  permanence  of  the  colors.  These  originated  in  France, 
about  the  time  of  Henry  IV.,  and  the  manufacture  was  much  patronized  by  that  monarch 
and  his  minister  Sully.  Louis  XIV.  and  Colbert,  however,  were  the  great  patrons  of  the 
beautiful  productions  of  the  loom.  The  minister  of  Louis  bought  from  the  Brothers  Gobe- 
lin their  manufactory,  and  transformed  it  into  a  royal  establishment,  under  the  title  of  ie 
Tcinturicr  Parfa'it.  A  work  was  published  in  1*740,  in  which  it  was.seriously  told  that  the 
dyes  of  the  Gobelins  had  acquired  such  superiority  that  tl>eir  contemporaries  attributed  the 
talent  of  these  celebrated  artists  to  a  paction  which  one  or  the  other  of  them  had  made  with 
the  devil. 

In  the  Gobelin  and  Beauvais  Tapestry  we  have  examples  of  the  most  artistic  productions, 
executed  with  a  mechanical  skill  of  the  highest  order,  when  we  consider  the  material  in 
which  the  work  is  executed.  The  method  of  nmnufacture  involving  artistic  power  on  the 
part  of  the  workman,  great  manipulatory  skill,  and  the  expenditure  of  much  time,  neces- 
sarily removes  those  productions  from  tlie  reach  of  any  but  the  wealthy.  Various  attempts 
have  been  made,  from  time  to  time,  to  produce  a  textile  fabric  which  should  equal  those 
tapestries  in  beauty,  and  which  should  be  sold  to  the  public  at  much  lower  prices.  None 
of  those  appear  to  have  been  successful  until  the  increasing  applications  of  India-rubber 
pointed  to  a  plan  by  which  high  artistic  excellence  might  be  combined  with  moderate  cost. 
In  Berlin,  and  subsequently  in  Paris,  plans — in  most  i-espects  similar  to  the  plan  we  are 
about  to  describe — were  tried,  but  in  neither  instance  with  complete  success.  Of  course, 
there  cannot  now  be  many  of  our  readers  who  have  not  been  attracted  by  the  very  life-like 
representations  of  lions  and  dogs  which  have  for  the  last  few  years  been  exhibited  in  the 
carpet  warehouses  of  the  metropolis,  and  other  large  cities.  While  we  admit  the  perfection 
of  the  manufacture,  we  are  compelled  to  remark  that  the  designs  which  have  been  chosen 
are  not  such  as  appear  to  us  to  be  quite  appropriate,  when  we  consider  the  purposes  for 
which  a  rug  is  intended.  Doubtless  from  their  very  attractive  character,  and  moderate 
cost,  those  rugs  find  a  large  number  of  purchasers,  by  whom  they  are  doubtless  greatly  ad- 
mired. It  will,  however,  be  obvious  to  our  readers,  that  they  are  not  consistent  with  the 
principles  of  design,  and  that  there  is  a  want  of  consistency  in  the  idea  of  treading  u])on  the 
"  monarch  of  the  forest,"  copied  with  that  remarkable  life-likeness  which  distinguishes  the 
productions  of  Sir  Edwin  Landsecr ;  or  in  placing  one's  feet  in  the  midst  of  dogs  or  of 
poultry,  when  the  resemblances  are  sufficiently  striking  to  impress  you  with  the  idea  that 
the  dogs  will  bark,  and  that  the  cock  will  crow.  We  believe  that  less  picturesque  subjects, 
in  accordance  with  the  law — which  we  conceive  to  be  the  true  one — which  gives  true 
beauty  only  to  that  which  is,  in  its  applications,  consistent  and  harmonious,  would  be  yet 
greater  favorities  than  those  rugs  now  manufactured  by  the  Messrs.  Crossleys.  And  amid.st 
the  amount  of  good  which  these  excellent  men  are  doing  to  all  who  come  within  their  in- 


MOSAIC  WOOL  WORK.  777 

fluence,  we  are  certain  they  might,  with  the  means  at  their  command,  introduce  an  arrange- 
ment ot"  colors  which  might  delight  by  their  harmonious  blending,  and  a  system  of  designs 
which,  pure  and  consistent,  should  ever  charm  the  eye,  without  attempting  to  deceive 
either  it  or  any  of  the  senses.  Every  attempt  to  advance  the  taste  of  a  people  is  worthy 
of  all  honor ;  and  having  the  power,  as  the  manufocturers  of  the  mosaic  rugs  have,  of 
producing  worlvs  of  the  highest  artistic  excellence,  we  should  be  rejoiced  to  see  them  em- 
ploying that  power  to  cultivate  amongst  all  classes  a  correct  perception  of  the  true  and  the 
beautiful. 

With  these  remarks  we  proceed  to  a  description  of  the  manufacture. 

Every  lady  who  has  devoted  herself  for  a  season,  when  it  was  the  fashion  to  do  so,  to 
Berlin  wool-work,  will  appreciate  the  importance  of  a  careful  arrangement  of  all  the  colored 
woi-steds  which  are  to  be  used  in  the  composition  of  her  design.  Here,  where  many 
hundreds  of  colors,  combinations  of  colors,  and  shades  are  required,  in  great  quantities 
and  in  long  lengths,  the  utmost  order  is  necessary  ;  and  the  system  adopted  in  this  establish- 
ment is  in  this  respect  excellent.  We  have,  for  example,  grouped  under  each  of  the 
primary  colors,  all  the  tints  of  each  respective  color  that  the  dyer  can  produce,  and  be- 
tween each  large  division  the  mixtures  of  color  producing  the  neutral  tones,  and  the  inter- 
blending  shades  which  may  be  required  to  copy  the  artist  with  fidehty.  Skeins  of  worsted 
thus  arranged  are  ever  ready  for  the  English  mosaicisti  in  rug-work.  Such  is  the  material. 
Now  to  describe  the  manner  of  proceeding.  In  the  first  place  an  artist  is  employed  to 
copy,  of  the  exact  size  required  for  the  rug,  a  work  of  Landseer's  or  any  other  master, 
which  may  be  selected  for  the  purpose.  Although  the  process  of  copying  is  in  this  case 
mechanical,  considerable  skill  is  required  to  produce  the  desired  result.  This  will  be 
familiar  to  all  who  have  observed  the  peculiar  characteristics  of  the  Berlin  wool-work  pat- 
tei'ns.  The  picture  being  completed,  it  is  ruled  over  in  squares,  each  of  about  twelve  inches. 
These  are  again  interruled  with  small  squares,  which  correspond  with  the  threads  of  which 
the  finished  work  is  to  consist.  This  original  being  completed,  it  is  copied  upon  lined  paper 
by  girls  who  are  trained  to  the  work,  each  girl  having  a  square  of  about  twelve  inches  to 
work  on.  These  are  the  copies  which  go  into  the  manufactory.  A  square  is  given  to  a 
young  woman  whose  duty  it  is  to  match  all  the  colors  in  wool.  This  is  a  task  of  great  deli- 
cacy, requiring  a  very  fine  appreciation  of  color.  It  becomes  necessary  in  many  cases  to  com- 
bine two  threads  of  wool,  especially  to  produce  the  neutral  tints.  It  is  very  interesting  to  ob- 
serve the  care  with  which  every  variety  of  color  is  matched.  The  skeins  of  worsted  are  taken, 
and  a  knot  or  knob  being  formed,  so  as  to  increase  the  quantity  of  colored  surface,  it  is 
brought  down  on  the  colored  picture  ;  and,  when  the  right  shades  have  been  selected,  they 
are  numbered,  and  a  corresponding  system  of  numbers  are  put  on  the  pattern.  In  many 
of  the  rugs  one  hundred  colors  are  employed.  The  selecter  of  colors  works  under  the 
guidance  of  a  master,  who  was  in  this  case  a  German  gentleman,  and  to  his  obliging  and 
painstaking  kindness  we  are  much  indebted.  Without  his  very  exact  description  of  every 
stage  of  the  process,  it  would  not  have  been  easy  to  render  this  rare  mosaic-work  intelligible 
to  our  readers.  When  all  the  colored  wools  have  been  selected,  they  are  handed,  with  the 
patterns,  to  young  women,  who  are  termed  the  •"  mistresses  of  a  frame,"  each  one  having 
under  her  charge  three  little  girls. 

The  "frame"  consists  of  three  iron  stands,  the  two  extreme  ones  being  about  200  inches 
apart,  and  the  other  exactly  in  the  middle.  These  stands  are  made  of  stout  cast  iron,  and 
may  be  said  to  consist  of  two  bowed  legs,  with  two  cross-pieces  of  iron,  one  at  the  top  of 
the  legs,  and  the  other  about  fifteen  inelies  below,  the  space  between  them  being  that  which 
is  to  be  occupied  by  the  threads  of  wool  which  are  to  form  the  required  square  block  of 
wool.  These  frames  are  united  together  by  means  of  cast-iron  tubes,  running  from  end  to 
end.  The  observer  is  struck  with  the  degree  of  strength  which  has  been  given  to  these 
frames.  It  appears  that,  for  the  purpose  of  merely  holding  together  a  few  threads  of  wool, 
a  much  slighter  frame  might  have  been  employed ;  and  we  certainly  were  surprised  when 
we  were  informed  that,  at  first,  many  frames  were  broken,  and  that  they  were  compelled  to 
have  the  stronger  ones  at  present  in  use.  The  cau.se  of  this  will  Ijc  obvious,  when  we  have 
proceeded  a  little  further  with  our  description.  At  one  end  of  these  frames  sits  the  "mis- 
tress," with  a  stand  before  her,  on  which  the  pattern  allotted  to  her  is  placed,  and  a  verti- 
cal frame,  over  which  the  long  colored  worsteds  are  arranged.  By  the  side  of  this  young 
woman  sits  a  little  girl,  who  receives  each  worsted  from  the  mistress,  and  hands  it  to  one 
of  two  children,  who  are  on  either  side  of  the  frame. 

Commencing  at  one  corner  of  the  pattern,  a  thread  is  selected  of  the  required  color, 
and  handed  to  the  fir.st  girl,  who  passes  it  to  the  second,  who.se  duty  it  is  to  fasten  it  to  a 
■stiff,  but  slight  liar  of  steel,  about  half  an  inch  in  width,  which  passes  from  the  upper  to  the 
under  ))ar  of  the  frame.  The  third  girl  receives  the  thread,  and  carries  it  to  the  lower  end 
of  the  frame,  and  fastens  it  to  a  simihir  bar  of  steel  at  that  end,  The  length  of  each  thread 
of  worsted  is  rather  more  than  'ioo  inches.  It  is  well  known  that  twisted  wool  iloes  not 
lie  quite  straight,  without  some  force  is  applied  to  it ;  and  of  course  the  finished  pattein 
would  be  incomplete,  if  all  the  threads  did  not  observe  the  truest  parallelism  to  each  other. 


778  MOSAIC  WOOL  WORK 

To  effect  this,  a  stretching  force  equal  to  four  pounds  is  required  to  every  thread.  The 
child  who  carries  the  thread,  therefore,  pulls  the  worsted  with  this  degree  of  force,  and 
fastens  it  over  the  steel  bar.  Every  block,  forming  a  foot-square  of  rug-work,  consists  of 
fifty  thousand  threads :  therefore,  since  every  thread  pulls  upon  the  frame  with  a  force 
equal  to  four  pounds,  there  is  a  direct  strain  to  the  extent  of  250,000  pounds  upon  the 
frame.  When  this  is  known,  our  surprise  is  no  longer  excited  at  the  strength  of  the  iron- 
work ;  indeed,  the  bars  of  hardened  steel,  set  edgeways,  were  evidently  bent  by  the  force 
exerted. 

Thread  after  thread,  in  this  way,  the  work  proceeds,  every  tenth  thread  being  marked 
by  having  a  piece  of  white  thread  tied  to  it.  By  this  means,  if  the  foreman,  when  he  ex- 
amines the  work,  finds  that  an  error  has  been  committed,  he  is  enabled  to  have  it  corrected, 
by  removing  only  a  few  of  the  threads,  instead  of  a  great  number,  which  would  have  been 
the  case,  if  the  system  of  marking  had  not  been  adopted. 

This  work,  requiring  much  care,  does  not  proceed  with  much  rapidity,  and  the  constant 
repetition  of  all  the  same  motions  through  a  long  period  would  become  exceedingly  monot- 
onous, especially  as  talking  cannot  be  allowed,  because  the  attention  would  be  withdrawn 
from  the  task  in  hand.  Singing  has  therefore  been  encouraged,  and  it  is  exceedingly  pleas- 
ing to  see  so  many  young,  happy,  and  healthy  faces  performing  a  clean  and  easy  task,  in 
unison  with  some  song,  in  which  they  all  take  a  part.  Harmonious  arrangements  of  color 
are  produced,  under  the  cheerful  influence  of  harmonious  sounds.  Yorkshire  has  long  been 
celebrated  for  its  choristers,  and  some  of  the  voices  which  we  heard  in  the  room  devoted  to 
the  construction  of  the  wool-mosaics  bore  evidence  of  this  natural  gift,  and  of  a  consider- 
able degree  of  cultivation. 

The  "  block,"  as  it  is  called,  is  eventually  completed.  This,  as  we  have  already  stated, 
is  about  a  foot  square,  and  it  is  200  inches  long.  Being  bound,  so  as  to  prevent  the 
disturbance  of  any  of  the  threads,  the  block  is  cut  by  means  of  a  very  sharp  knife  into  ten 
parts,  so  that  each  division  will  have  a  depth  of  about  20  inches.  Hearth-rugs  are  ordinarily 
about  eight  feet  long,  by  about  two  feet  w  ide,  often,  however,  varying  from  these  dimensions. 
Supposing,  however,  this  to  represent  the  usual  size,  twelve  blocks,  from  as  many  different 
frames,  are  placed  in  a  box,  with  the  threads  in  a  vertical  position,  so  that,  looking  down 
upon  the  ends,  we  see  the  pattern.  These  threads  are  merely  sustained  in  their  vertical 
order  by  their  juxtaposition.  Each  box  therefore,  will  contain  800,000  threads.  The  rug 
is  now,  so  far  as  the  construction  of  the  pattern  is  required  completed  ;  and  the  cost  of 
producing  the  "  block,"  of  200  inches  in  depth,  eight  feet  in  length,  and  two  feet  wide,  in- 
cluding the  cost  of  wool,  and  the  payment  for  labor,  is  little  short  of  £800.  When,  how- 
ever, it  is  known  that  these  threads  are  subsequently  cut  into  the  length  required  to  form 
the  rug,  and  that  these  lengths  are  but  the  three-sixteenths  of  an  inch  in  depth,  it  will  be 
evident  that  the  number  of  those  beautiful  carpets  which  can  thus  be  obtained,  renders  the 
manufacture  fairly  remunerative.  The  boxes  into  which  the  rugs  are  placed  are  fixed  on 
wheels,  and  they  have  movable  bottoms,  the  object  of  which  will  be  presently  understood. 
From  the  upper  part  of  the  immense  building  devoted  to  carpet  manufacture,  in  which  this 
mosaic  rug-work  is  carried  on,  we  descend  with  our  rug  to  the  basement  store.  Here  we 
find,  in  the  first  place,  steam  chests,  in  which  India-rubber  is  dissolved  in  eamphene.  It 
may  not  be  out  of  place  to  observe  that  eamphene  is  actually  spirits  of  turpentine,  carefully 
rectified,  and  deprived  of  much  of  its  smell  by  being  distilled  from  either  potash  or  soda. 
Recently  prepared  eamphene  has  but  little  of  the  terebinthinous  odor,  but  if  it  is  kept  long, 
and  especially  if  it  is  exposed  to  the  air,  it  again  acquires,  with  the  absorption  of  oxygen, 
.  its  original  smell.  This  is  of  course  avoided  in  the  manufacture  of  such  an  article  as  a 
hearth-rug  as  much  as  possible.  The  eamphene  is  used  as  fresh  as  possible,  and  in  it  the 
India-rubber  is  dissolved,  until  we  have  a  fluid  about  the  consistence  of,  and  in  appearance 
like,  carpenter's  glue. 

In  an  adjoining  room  were  numerous  boxes,  each  one  containing  the  rug-work  in  some 
of  the  stages  of  manufacture.  It  must  now  be  remembered  that  each  box  represents  a 
completed  rug — the  upper  ends  of  the  threads  being  shaved  off",  to  present  as  smooth  a  sur- 
face as  possible.  In  every  stage  of  the  process  now  all  damp  must  be  avoided,  as  wool,  like 
all  other  porous  bodies,  has  a  tendency  to  absorb  and  retain  moisture  from  the  atmosphere. 
The  boxes,  therefore,  are  placed  in  heated  chambers,  and  they  remain  there  until  all  moist- 
ure is  dispelled ;  when  this  is  effected,  a  layer  of  India-rubber  solution  is  laid  over  the 
surface,  care  being  taken,  in  the  application,  that  every  thread  receives  the  proper  quantity 
of  tlie  caoutchouc ;  tliis  is  dried  in  the  warm  chamber,  and  a  second  and  a  third  coat  is  given 
to  the  fibres.  While  the  last  coat  is  being  kept  in  the  Avarm  chamber,  free  from  all  dust, 
sufficiently  long  to  dissipate  some  of  the  eamphene,  the  surface  on  which  the  rug  is  to  be 
placed  receives  similar  treatment.  In  some  cases  ordinary  carpet  canvas  only  is  employed  ; 
in  others,  a  rug  made  by  weaving  in  the  ordinary  manner  is  employed,  so  that  either  side 
of  the  rug  can  be  turned  up  in  the  room  in  which  it  is  placed.  However  this  may  be,  both 
surfaces  are  properly  covered  with  soft  caoutchouc,  and  the  "backing"  is  carefully  placed 
on  the  ends  of  worsted  forming  the  rug  in  the  box.     By  a  scraping  motion,  the  object  of 


MUREXIDE. 


779 


which  is  to  remove  all  air-bubbles,  the  union  is  perfectly  effected  ;  it  is  then  placed  aside  for 
some  little  time,  to  secure  by  rest  that  absolute  union  of  parts,  between  the  two  india- 
rubber  surfaces,  which  is  necessary.  The  separation  of  the  two  parts  is  after  this  attended  with 
the  utmost  ditficulty  ;  the  worsted  may  be  broken  by  a  forcible  pull,  but  it  cannot  be  removed 
from  the  india-rubber.  The  next  operation  is  tliat  of  cutting  off  the  rug;  for  this  purpose 
a  very  admirable,  but  a  somewhat  formidable  machine  is  required.  It  is,  in  principle,  a 
circular  knife,  of  twelve  feet  diameter,  mounted  horizontally,  which  is  driven,  by  steam- 
power,  at  the  rate  of  170  revolutions  in  a  minute. 

The  rug  in  its  box  is  brought  to  the  required  distance  above  the  edge  of  the  box,  by 
screwing  up  the  bottom.  The  box  is  then  placed  on  a  rail,  and  connected  with  a  tolerably 
fine  endless  screw.  The  machine  being  put  in  motion,  the  box  is  carried  by  the  screw  under 
the  knife,  and  by  the  rapid  circular  motion,  the  knife  having  a  razor-like  edge,  a  very  clean 
cut  is  effected.  As  soon  as  the  rug  is  cut  off,  to  the  extent  of  a  few  inches,  it  is  fastened 
by  hooks  to  strings  which  wind  over  cylinders,  and  thus  raise  the  rug  as  regularly  as  it  is 
cut.  This  goes  on  until  the  entire  rug  is  cut  off  to  the  thickness  of  three  sixteenths  of  an 
inch.  The  other  portion  in  the  box  is  now  ready  to  receive  another  coating,  and  the 
application  of  another  surface,  to  form  a  second  rug,  and  so  on,  until  about  one  thousand 
rugs  are  cut  from  the  block  prepared  as  we  have  described. 

The  establishment  of  the  Messrs.  Crossley,  which  gives  employment  to  four  thousand 
people,  is  one  of  those  vast  manufactories  of  w  hich  England  may  proudly  boast,  as  examples 
of  the  industry  and  skill  of  her  sons.  Here  we  have  steam  engines  urging,  by  their  gigan- 
tic throes,  thousands  of  spindles,  and  hundreds  of  shuttles,  and  yet,  notwithstanding  the 
human  labor  which  has  been  saved,  there  is  room  for  the  exertion  of  four  thousand  people. 
The  manner  in  which  this  great  mass  of  men,  women,  and  children  is  treated,  is  marked  in 
all  the  arrangements  for  their  comfort,  not  merely  in  the  great  workshop  itself,  but  in  every 
division  of  that  hill-encompassed  town,  Halifax.  Church,  schools,  and  park  proclaim  the 
high  and  liberal  character  of  those  great  carpet  manufacturers,  one  division,  and  that  a  small 
one,  of  whose  works  we  have  described. 

MOULDS,  ELASTIC.  Being  much  engaged  in  taking  casts  from  anatomical  prepara- 
tions, Mr.  Douglas  Fox,  surgeon,  Derby,  found  great  difficulty,  principally  with  hard  bodies, 
which,  when  imdercut,  or  having  considerable  overlaps,  did  not  admit  of  the  removal  of 
moulds  of  the  ordinary  kind,  except  with  injury.  The  difficulties  suggested  to  him  the  use 
of  elastic  moulds,  which,  giving  way  as  they  were  withdrawn  from  complicated  parts,  would 
return  to  their  proper  shape  ;  and  he  ultimately  succeeded  in  making  such  moidds  of  glue, 
which  not  only  relieved  him  from  all  his  difficulties,  but  were  attended  with  great  advantages, 
in  consequence  of  the  small  number  of  pieces  into  which  it  was  necessary  to  divide  the  mould. 

The  body  to  be  moulded,  previously  oiled,  must  be  secured  one  inch  above  the  surface 
of  a  board,  and  then  surrounded  by  a  wall  of  clay,  about  an  inch  distant  from  its  sides. 
The  clay  must  also  extend  rather  higher  than  the  contained  body  :  into  this,  warm  melted 
glue,  as  thick  as  possible  so  that  it  will  run,  is  to  be  poured,  so  as  to  completely  cover  the 
body  to  be  moulded  :  the  glue  is  to  remain  till  cold,  when  it  will  have  set  into  an  elastic 
mass,  just  such  as  is  required. 

Having  removed  the  clay,  the  glue  is  to  be  cut  into  as  many  pieces  as  may  be  necessary 
for  its  removal,  either  by  a  sharp-pointed  knife,  or  by  having*  placed  threads  in  tlie  requi- 
site situations  of  the  body  to  be  moulded,  which  may  be  drawn  away  when  the  glue  is  set, 
so  as  to  cut  it  out  in  any  direction. 

The  portions  of  the  glue  mould  having  been  removed  from  the  original,  are  to  be  placed 
together  and  bound  round  by  tape. 

In  some  instances  it  is  well  to  run  small  wooden  pegs  through  the  portions  of  glue,  so 
as  to  keep  them  exactly  in  their  proper  positions.  If  the  mould  be  of  considerable  size,  it 
is  better  to  let  it  be  bound  with  moderate  tightness  upon  a  board  to  prevent  its  bending 
whilst  in  use ;  having  done  as  above  described,  the  plaster  of  Paris,  as  in  common  casting, 
is  to  be  poured  into  the  mould,  and  left  to  set. 

In  many  instances  wax  may  also  be  cast  in  glue,  if  it  is  not  poured  in  whilst  too  hot,  aa 
the  wax  cools  so  rapidly  when  applied  to  the  cold  glue  that  the  sharpness  of  the  impression 
is  not  injured. 

Glue  has  been  described  as  succeeding  well  where  the  elastic  mould  is  alone  applicable ; 
but  many  modifications  are  admissible.  When  the  moulds  are  not  used  soon  after  being 
made,  treacle  should  be  previously  mixed  with  thq  glue  (as  employed  by  printei-s)  to  pre- 
vent its  becoming  hard. 

The  description  thus  given  is  with  reference  to  moulding  those  bodies  which  cannot  be 
so  done  by  any  other  than  an  elastic  mould  ;  but  glue  moulds  will  be  found  greatly  to  facili- 
tate casting  in  many  departments,  as  a  mould  may  be  frequently  taken  by  this  method  in 
two  or  three  pieces,  which  would,  on  any  other  i)rinciple,  require  manv. 

MUREXIDE.  Syn.  Purpnrate  of  Ammonia.  C'lrN'O'^  Murc'xide  is  one  of  those 
substances  which,  although  investigated  by  many  chemists  of  great  reputation,  has  long  been 
regarded  as  of  uncertain  constitution.     This  is  the  more  remarkable  from  the  fact  that, 


780  MUREXIDE. 

owing  to  its  extreme  beauty,  it  has  always  attracted  a  large  amount  of  attention.  It  is  in- 
variably formed  when  the  product  of  the  action  of  moderately  strong  nitric  acid  on  uric 
acid  is  treated  with  ammonia.  The  process,  however,  is  rather  valuable  as  a  test  of  the 
presence  of  uric  acid,  than  as  a  method  of  procuring  murexide.  Dr.  Gregory,  who  has 
given  much  attention  to  the  best  methods  of  preparing  the  substance  in  question,  has 
jiublished  the  following  formula  for  working  on  the  small  scale: — "Four  grains  of  allox- 
antine  and  seven  grains  of  hydrated  alloxan  are  dissolved  together  in  half  an  ounce  by 
measure  of  water  by  boiling,  and  the  hot  solution  is  added  to  one-sixth  of  an  ounce  by 
measure  of  a  saturated  or  nearly  saturated  solution  of  carbonate  of  ammonia,  the  latter 
being  cold.  This  mixture  has  exactly  the  proper  temperature  for  the  formation  of  murex- 
ide ;  and  it  does  not,  owing  to  its  small  bulk,  remain  too  long  hot.  It  instantly  becomes 
intensely  purple,  while  carbonic  acid  is  expelled ;  and  as  soon  as  it  begins  to  cool,  the 
beautiful  green  and  metallic-looking  crystals  of  murexide  Vjegin  to  appear.  As  soon  as  the 
liquid  is  cold,  these  may  be  collected,  washed  with  a  little  cold  water,  and  dried  on  filter- 
ing paper. 

The  analyses  of  murexide  are  rather  discordant,  the  carbon  in  all  of  them  being  in  excess. 
This  arises  from  the  very  large  amount  of  nitrogen  present,  a  certain  portion  becoming 
acidified  passes  into  the  potash  apparatus,  causing  an  undue  increase  in  its  weight. 

There  appears  no  doubt  whatever  that  the  formula  C'^X^lPO'^  represents  its  true  com- 
position, ilurexide  is  formed  when  uramile,  murexane,  or  dialuramide,  as  it  is  sometimes 
called,  is  boiled  with  peroxide  of  mercury.  Dr.  Gregory  regarded  murexane  as  a  separate 
substance,  and  as  identical  with  pur])uric  acid  :  he  also  considered  C'X^H^O^  as  its  probable 
formida.  This  appears  from  more  recent  researches  to  be  incorrect,  as  murexane  is  doubt- 
less the  same  substance  as  uramile,  while  purpuric  acid,  which  is  bibasic,  is  represented  by 
the  formula  C'lPN'O".  Tlie  formulaj  above  given  for  murexide  and  uramile  renders  the 
reaction  of  peroxide  of  mercury  with  the  latter  easily  intelligible  ;  it  is,  in  fact,  a  very  simple 
case  of  oxidation,  thus : — 

2C»X'H'0''-|-  20r=C"'X'IF0'-  -f  2H0 

Uramile.  Murexide. 

The  limits  of  this  work  preclude  any  further  notice  of  the  scientific  relations  of  mui-ex- 
ide,  but  it  is  necessary  that  we  should  consider  it  in  its  character  as  a  dye-stuff".  It  has 
been  found  that  murexide  forms  a  series  of  beautiful  compounds  with  certain  metallic 
oxides,  more  especially  lead  and  mercury,  and  these  compounds  have  been  employed  to  a 
very  large  extent  in  the  dyeing,  and  more  especially  printing  of  cotton  goods.  It  is  plain 
that  if  uric  acid  were  only  obtainable  from  the  urine  of  serpents  or  the  sediments  from  the 
urine  of  mammalia,  it  could  never  be  made  use  of  in  the  arts.  It  happens,  however,  that 
the  solid  urine  of  birds  contains  it  in  large  quantity,  and  since  we  have  become  acquainted 
with  the  vast  deposits  of  guano  existing  in  various  parts  of  the  globe,  tlie  manufacture  of 
murexide  has  been  carried  out  on  a  scale  which  would,  a  few  years  ago,  have  appeared  im- 
possible. We  must,  in  order  to  be  -c-lear,  divide  the  process  into  two  parts,  one  being  the 
preparation  of  uric  acid  from  guano,  the  other  the  conversion  of  the  acid  into  murexide. 

Preparation  of  uric  acid  from  guano. — ^^In  order  to  get  Tid,  as  much  as  possible,  of  the 
impurities  contained  in  the  guano,  it  is  in  the  first  place  to  be  treated  with  muriatic  acid, 
which  will  remove  carbonate  and  oxalate  of  ammonia,  carbonate  and  phosphate  of  lime, 
and  ammonio-magncsian  phosphate.  The  uric  acid  will  also  be  liberated  from  the  substances 
with  which  it  may  l)c  in  combination.  The  operation  may  be  performed  in  a  leaden  vessel, 
heated  with  a  leaden  coil,  through  which  steam  passes.  It  is  essential  to  success  that  the 
guano  be  added  slowly,  otherwise  the  violent  effervescence,  which  is  caused  by  the  decom- 
position of  the  carbonates  by  the  acid,  would  cause  the  liquid  to  escape  from  the  vessel. 
The  mixture  of  guano  and  mnriatic  acid  is  then  to  be  heated  for  an  hour,  after  which  it 
may  be  run  off"  into  tubs,  to  bo  washed  with  water  by  decantation.  The  first  washings  con- 
tain a  large  quantity  of  ammonia  in  the  state  of  sal  ammonia  ;  it  should  be  worked  up  in 
some  way,  in  order  to  prevent  the  loss  of  so  vahialjje  a  salt.  As  soon  as  the  residue  of  the 
guano  is  sufficiently  washed,  it  may  be  transferred  to  cloth  filters  and  allowed  to  drain.  The 
residue  from  the  action  of  muriatic  acid  upon  200  lbs.  of  guano  can  now  be  treated  by 
Draun's  process  for  the  extraction  of  the  uric  acid.  It  is  to  be  placed  in  a  copper  boiler  of 
sufficient  capacity,  and  boiled  for  an  hour  with  8  pounds  of  caustic  .soda  and  120  gallons  of 
water.  It  must  be  constantly  stirred.  Two  or  three  pounds  of  quicklime  are  now  to  be 
slaked,  enough  water  is  then  to  be  added  to  make  the  whole  into  a  thin  paste,  which  is  to 
be  poured  into  the  mixture  of  caustic  soda  and  guano  residue.  After  a  quarter  of  an  hour's 
boiling,  the  fire  is  to  be  removed  and  the  whole  allowed  to  repose  until  clear.  The  bright 
li<iuid  having  been  siphoned  oft"  from  the  residue,  the  latter  is  to  be  treated  with  120  gallons 
more  water  and  6  pounds  of  soda ;  2  pounds  of  slaked  lime  are  also  to  be  added  in  the  .same 
manner  as  in  the  first  operation.  The  lime  is  for  the  purpose  of  removing  extractive 
matter,  and  it  has  been  found  that  it  does  not  do  to  use  it  in  any  other  manner  than  that 
described.     If  the  soda  and  lime  be  allowed  to  react  upon  the  guano  residue  at  the  same 


MUSLI2T.  781 

time,  urate  of  lime  is  formed,  which,  owing  to  its  comparative  insolubility,  causes  much 
troul)le  in  the  subsequent  operations. 

The  two  alkaline  fluids  containing  the  urate  of  soda  are  to  be  precipitated  while  warm 
by  a  moderate  excess  of  hydrochloric  acid.  Tiie  precii)itated  uric  acid  is  then  to  be  washed 
with  water  and  dried. 

Conversion  of  the  uric  acid  into  nmrcxide  bi/  Braun''s  procesn. — In  the  first  place,  a  very 
large  bath  of  cold  water  must  be  provided,  having  a  number  of  earthenware  basins  floating 
upon  it.  Into  each  of  these  basins  2^  pounds  of  nitric  acid  are  to  be  poured,  the  strength 
of  the  acid  being  36°  Beaume.  One  pound  and  three  quarters  of  the  uric  acid,  prepared 
as  above,  is  now  to  be  added  by  very  small  quantities  at  a  time.  If  the  temperature  rise 
above  90^  F.  the  whole  is  to  be  allowed  to  cool  before  adding  any  more  uric  acid.  If  the 
water  in  the  bath  be  so  cold  that  the  temperature  falls  so  low  as  to  stop  the  reaction,  it  may 
be  set  up  again  by  adding  warm  water  to  the  bath,  or,  more  conveniently,  by  sending  some 
steam  into  it  for  a  short  time.  At  first  the  uric  acid  need  only  be  added  to  the  nitric  acid 
by  sprinkling  it  on  the  surface,  towards  the  end  of  the  operation  ;  when  the  nitric  acid  has 
become  enfeebled,  it  is  necessary  to  stir  it  in.  The  quantity  of  mixture  contained  in  two 
basins  is  now  to  be  placed  in  an  enamelled  iron  pot  on  a  sand-bath.  As  tlie  heat  increases 
the  fluid  will  boil  up  in  the  pot,  and  to  prevent  loss  the  vessel  must  be  removed  from  the 
tire  for  a  short  time.  The  heating  is  to  be  repeated  in  this  manner  until  the  temperature 
rises  to  248°  F.,  and,  after  removing  the  pot  to  the  coolest  part  of  the  sand-bath,  half  a 
pound  of  liquid  ammonia  is  to  be  stirred  in  quickly.  In  a  few  minutes  the  whole  is  convert- 
ed into  what  is  called  in  commerce  by  the  name  of  Murcxide  en  pate.  To  convert  this  into 
the  purer  product  known  as  Murcxide  en  poudre,  it  is  to  be  repeatedly  stirred  up  with  water 
and  filtered,  to  remove  the  saline  and  extractive  matters. 

In  dyeing  cotton  by  means  of  murcxide,  it  is  necessary  to  use  lead  and  mercury  as 
mordants.  Lauth's  process  consists  in  fixing  oxide  of  lead  upon  the  fibre  by  first  immers- 
ing it  in  a  bath  of  acetate  of  lead,  and  then  in  ammonia,  or  by  a  bath  of  oxide  of  lead  and 
lime.  The  dye  is  then  mixed  with  pernitrate  or  perchloride  of  mercury  and  a  little  acetate 
of  soda,  and  the  cotton  goods  are  worked  in  it  for  a  sufficient  time. 

For  printing,  the  murcxide  is  mixed  with  thickened  nitrate  of  lead,  and  the  cloth  after 
printing  is  dried  and  subsequently  passed  through  a  bath,  containing  100  litres  of  water,  1 
kilogramme  of  corrosive  sublimate,  and  1  kilogramme  of  acetate  of  soda. 

In  Sagar  and  Schultz's  patent  process  they  pad  the  cotton  goods  in  a  solution  of  murcx- 
ide with  6  pounds  of  nitrate  of  lead  in  8  gallons  of  water,  to  which  when  cold  G  ounces  of 
corrosive  sublimate  dissolved  in  2  gallons  of  water  are  added.  The  goods  are  dried  after 
dyeing  in  the  above  solution,  and  the  color  is  fixed  by  again  padding  in  a  solution  of  wheaten 
starch,  gum,  gum  substitute,  or  any  similar  substance. 

Silk  may  easily  be  dyed  in  a  bath  of  murexide  mixed  with  corrosive  sublimate.  Wool, 
after  being  well  washed  and  rinsed,  is  to  be  dyed  in  a  strong  bath  of  murexide,  and  then 
dried.  It  is  after  this  to  be  treated,  at  a  temperature  of  104°  to  122°  F.,  with  a  bath  con- 
taining 60  grammes  of  corrosive  sublimate,  75  grammes  of  acetate  of  soda,  and  10  litres  of 
water. — G.  G.  W. 

MUSLIN,  To  render  it  and  other  fabrics  non-inflammable.  This  very  important 
inquiry  was  committed  by  Professor  Graham,  at  the  desire  of  Her  Majesty,  to  the  care  of 
Dr.  Oppeuheim  and  Mr.  Frederick  Versmann,  from  whose  report  the  following  important 
conclusions  have  been  abstracted.  After  naming  many  salts  found  to  be  useless,  or  nearly 
so,  they  proceed  : — "  With  regard  to  sulphate  of  ammonia,  the  cheapest  salt  of  ammonia,  a 
solution  containing  7  percent,  of  the  crystals,  or  6'2  percent,  of  anhydrous  salt,  isa  perfect 
anti-flammable.  In  1839,  the  Bavarian  embassy  at  Paris  caused  M.  Chevalier  to  make  ex- 
periments before  them  with  a  mixture  of  borax  and  sulphate  of  ammonia,  as  recommended 
by  Chevalier,  in  preference  to  the  sulphate  alone.  He  thought  the  sulphate  would  lose 
part  of  its  ammonia,  and  thereby  give  rise  to  the  action  of  sulphuric  acid  upon  the  fabric. 
Tiiis  opinion  seems  to  be  confirmed  by  the  fact  that  a  solution  of  sidphate  of  ammonia 
gives  olF  ammonia,  as  observed  by  Dr.  K.  A.  Smitii  in  his  paper  on  substances  which  prevent 
fabrics  from  flaring ;  but  on  the  other  hand,  this  may  be  easily  counteracted  by  adding  a 
little  carljonate  of  ammonia,  and  besides,  the  solid  salt  remains  perfectly  undecomposeil. 
The  authors  say  tliat  they  now  have  kept  for  six  montlis  whole  pieces  of  muslin  prepared  in 
various  ways  with  this  salt,  some  having  been  even  ironed  ;  but  cannot  find  that  the  texture 
was  in  the  least  degree  weakened.  Clievalier's  mixture,  on  the  contrary,  became  injurious 
to  the  fabric,  not  only  at  temperatures  above  212°,  but  even  at  sunnncr  heat;  and  tliis  can 
.  easily  be  explained,  l)ccauso  lie  did  not  actually  apply  sulphate  of  ammonia  and  borax,  but 
l)iborato  of  ammonia  and  sulpiiato  of  soda." 

Another  dra\vl)ai-k  of  Clievalier's  mixture  is  the  roughness  which  it  gives  to  the  fabric, 
and  which  CDud  only  be  overcome  by  c.dendering  the  pieces,  while  sulphate  of  ammonia 
liy  itself  has  n<)t  this  effect. 

The  use  of  this  salt  must  therefore  be  strongly  recommended. 

Of  all  the  salts  experimented  upon,  only  four  appear  to  be  applicable  for  light  fabrics. 


782  MUSLIN. 

These  salts  are  the 

1.  Phosphate  of  ammonia. 

2.  The  mixture  of  phosphate  of  ammonia  pnd  chloride  of  ammonium. 

3.  Sulphate  of  ammonia. 

4.  Tungstate  of  soda. 

The  sulphate  of  ammonia  is  by  far  the  cheapest  and  the  most  efficacious  salt,  and  it  was 
therefore  tried  on  a  large  scale.  Whole  pieces  of  muslin  (eight  to  sixteen  yards  long)  were 
finished,  and  then  dipped  into  a  solution  containing  10  per  cent,  of  the  salt,  and  dried  in 
the  hydro-extractor.  This  was  done  with  printed  muslins,  as  well  as  with  white  ones,  and 
none  of  the  color  gave  way,  with  the  sole  exception  of  madder  purple,  which  became  pale. 
But  even  this  change  might  be  avoided,  if  care  be  taken  not  to  expose  the  piece  while  wet 
to  a  higher  than  ordinary  temperature.  Most  of  these  experiments  were  made  at  the  works 
of  Mr.  Crum  and  of  Mr.  Cochran.  The  pieces  had  a  good  finish,  and  some  of  them  were 
afterwards  submitted  to  Her  Majesty  for  inspection,  who  was  pleased  to  express  her  satis- 
faction. 

Mr.  Crum,  who  prepared  some  dresses  with  phosphate  and  some  with  sulphate  of  am- 
monia, arrives  at  the  result,  that,  with  the  phosphate,  the  finish  is  chalky,  and  not  trans- 
parent enough,  whereas  the  finish  with  the  sulphate  is  successful. 

Other  pieces,  prepared  with  the  sulphate,  were  exhibited  in  the  Exhibition  of  Inventiors 
of  the  Society  of  Arts,  and  at  the  Conversazione  of  the  Pharmaceutical  Society,  in  July  last. 
During  the  space  of  six  months  none  of  the  fabrics  prepared  with  sulphate  of  ammonia  have 
changed  either  in  color  or  in  texture  ;  it  may  therefore  be  considered  as  an  established  fact 
that  the  sulphate  of  ammonia  may  be  most  advantageously  applied  in  the  finishing  of 
mu.'slins  and  similar  highly  inflammable  fabrics. 

The  authors  felt,  however,  the  necessity  of  inquiring  further  into  the  effect  which  iron- 
ing would  have  upon  fabrics  thus  prepared  ;  for  all  the  above  mentioned  salts,  being  soluble 
in  water,  require  to  be  renewed  after  the  prepared  fabrics  have  been  washed. 

Now,  the  sulphate  of  ammonia  does  not  interfere  with  the  ironing  so  much  as  other  salts 
do,  because  a  comparatively  small  portion  is  required ;  but  still,  the  difficulty  is  unpleasant, 
and  sometimes  a  prepared  piece,  after  being  ironed,  showed  brown  spots  like  iron-moulds. 
On  covering  the  iron  with  plates  of  zinc  or  brass,  these  spots  did  not  appear ;  but  the 
difficulty  still  existed,  and  a  white  precipitate  covering  the  plate,  showed  evidently  that  it 
is  the  volatile  nature  of  the  salt  which  interferes  with  the  process.  An  attempt  to  counter- 
act this  action  of  the  salt,  by  adding  wax  and  similar  substances  to  the  starch,  remained  also 
without  any  result. 

For  all  laundry  purposes,  the  tungstate  of  soda  only  can  be  recommended.  This  salt 
offers  only  one  difficulty,  viz.,  the  formation  of  a  bitungstate,  of  little  solubility,  which 
crystallizes  from  the  solution.  To  obtain  a  constant  solution,  this  inconvenience  must  be 
surmounted ;  and  it  was  found  that  not  only  phosphoric  acid,  in  very  small  proportion, 
keeps  the  solution  in  its  original  state,  but  that  a  small  percentage  of  phosphate  of  soda  has 
the  same  effect. 

The  best  way  of  preparing  a  solution  of  minimum  strength  is  as  follows: — A  concen- 
trated neutral  solution  of  tungstate  of  soda  is  diluted  with  water  to  28°  Twaddle,  and  then 
mixed  with  3  per  cent,  of  phosphate  of  soda.  This  solution  was  found  to  keep,  and  to 
answer  well ;  it  has  been  introduced  into  Her  Majesty's  laundry,  where  it  Is  constantly 
being  used. 

The  effects  of  the  soluble  salts  having  been  thus  compared,  a  few  remarks  are  necessary 
respecting  the  means  which  may  be  adopted  permanently  to  fix  anti-flammable  expedients, 
so  that  the  substances  prepared  may  be  wetted  without  losing  the  property  of  being  non- 
inflammable. 

Relying  upon  the  property  of  alumina  as  a  mordant,  we  tried  the  combination  of  oxide 
of  zinc  and  alumina,  obtained  by  mixing  solutions  of  oxide  of  zinc  in  ammonia  and  of 
alumina  in  caustic  soda ;  but  although  this  precipitate  protects  the  fibre,  it  does  not  adhere 
to  it  when  wa,shcd. 

The  oxychloride  of  antimony,  obtained  by  precipitation  from  an  acid  solution  of  chloride 
of  antimony  by  water  mixed  with  only  a  little  ammonia,  is  a  good  anti-flammable,  and  it 
withstands  the  action  of  water,  but  not  that  of  soap  and  soda.  It  was  not  found  that  the 
solution  of  this  and  other  salts  in  muriatic-acid  injured  the  texture  of  the  fabric,  as  long  as 
this  was  dried  at  an  ordinary  temperature 

The  borate  and  phosphate  of  protoxide  of  tin  act  effectually,  if  precipitated  in  the  fibre 
from  concentrated  solutions  of  these  salts  in  muriatic  acid  by  ammonia ;  they  withstand  the 
influence  of  wa.shing,  but  give  a  yellow  tinge  to  the  fabrics. 

The  same  remarks  apply  to  arseniate  of  tin.  The  stannates  of  lime  and  zinc  protect 
the  fabric,  but  do  not  withstand  the  action  of  soap  or  soda. 

The  oxides  of  tin  give  a  favorable  result,  inasmuch  as  they  really  can  be  permanently 
fixed ;  the  yellow  tinge,  however,  which  they  impart  to  the  fabrics  will  always  confine  their 
application  to  coarse  substances,  such  as  canvas,  sail-cloth,  or  ropes. 


MUSLIX. 


783 


Table  I. 

Shoioinn  the  smallest  percentage  of  Salts  required  in  Solution,  for  rendering  Muslin  Non- 
inflammable;  A,  of  Crystallized;  B,  of  Aitht/drous  Salts.  Twelve  square  t7iches  of  the 
Jfuslin  employed  weighed  33-4  grains.  ^ 


Name  of  Salts. 


B. 


Caustic  soda     - 
Carbonate  of  soda     - 
Carbonate  of  potash 

Bicarbonate  of  soda  - 

Borax 

Silicate  of  soda 
Phosphate  of  soda    - 

Sulphate  of  soda 

Bisulphate  of  soda    - 
Sulphite  of  soda 

Tungstate  of  soda     ■ 


Stannate  of  soda 
Chloride  of  sodium  -         -         - 
Chloride  of  potassium 
Cyanide  of  potassium 
Sesquicarbonate  of  ammonia 
Oxalate  of  ammonia 
Biborate  of  ammonia 
Phosphate  of  ammonia,     - 

Phosphate  of  ammonia  and  soda 

Sulphate  of  ammonia 

Sulphite  of  ammonia 
Chloride  of  ammonium 
Iodide  of  ammonium 
Bromide  of  ammonium 

Urea 

Thouret's  mixture     -         -         - 
Chloride  of  barium  -         -         - 
Chloride  of  calcium  -         -         - 
Sulphate  of  magnesia 
Sulphate  of  alumina 
Potash  —  alum         .         .         . 
Ammonia  —  alum    -         -         - 
Sulphate  of  iron        .         .         . 
Sulphate  of  copper  -         -         - 
Sulphate  of  zinc        .         .         . 
Chloride  of  zinc        .         .         - 
I  Protochloride  of  tin 
Protochloride  of  tin  and  ammo- 
nium     

Pinksalt 


27 
12-6 

6 

25 

80 


20 
25 


20 
20 


15 

7 
10 


19-7 

50 

15 

33 

25 

54 

18 

20 

8 

5 

5 


6-2 
10 
10 

5-4 

13-2 
15-5 
32 


Remarks. 


18-5 
10-3 


16 
15-9 


10 


10 
9-8 

6-2 

9 
25 

5 

5 
40 
12 
50 
10 
24-3 

7-7 
18 
13 
28-8 
10 
11-2 

5-8 

4-6 

4-7 
7 


•  Injurious  to  the  fabrics. 

Not  sufficiently  efficacious ;  too  vola- 
tile. 

Destroys  the  fabrics  above  212°  Fahr. 

Injures  the  appearance  of  the  fabrics. 

Not  sufficiently  efficacious, 
i  A  concentrated  72  p.  c.  solution  is 
I      insufficient. 

-  Destroys  the  fabrics. 

Recommended  on  account  of  its  being 
the  only  salt  not  interfering  with 
the  ironing  of  the  fabrics. 
Injurious 
)  Concentrated    solutions    are   insuffi- 
I      cient. 
Poisonous. 

t  Not  available. 

Destroys  the  fabrics  above  212°. 

Efficient,  but  expensive, 
j  Expensive,   and  scarcely  sufficiently 
I      efficacious. 

]  Very  efficient,  and  recommended  on 
\      account  of  its  low  price. 

Deliquescent. 

Not  sufficiently  efficacious. 

Too  expensive. 

Efficient,  but  expensive. 

Not  sufficiently  efficacious. 

Deliquescent. 

Not  sufficiently  efficacious. 

Destroys  the  fabric. 
)  Not  efficacious  enough,  and  destroys 
)      the  fabric. 

Not  sufficiently  efficacious. 

[•  Poisonous. 

Deliquescent. 

Deliquescent, 
j  Becomes  yellow,  when  exposed  to  the 
I      air. 

Injures  the  fabric 


Table  II. 

Showing  the  increase  in  might  of  Muslin  prepared  vnth  various  anti-flammable 

expedients. 


Muslin  (not  starched)  prepared  with  a  solution  of 

Increased  in  weight  about 

7  per  cent,  of  sulphate  of  ammonia 
10  per  cent,  of  tungstate  of  soda        .... 
12  per  cent,  of  Thouret's  compound            ... 

1 8  per  cent. 
27  per  cent. 
24  per  cent. 

784  NAPHTHA. 

The  canvas  thus  prepared  must  be  dried  and  then  washed,  to  remove  the  excess  of 
precipitate.     Salt  water  does  not  remove  the  tin  from  the  canvas. 

A  piece  about  forty  yards  in  length  has  been  prepared  by  order  of  the  storekeeper-gen- 
eral of  the  Royal  Navy ;  but  it  was  found  to  have  lost  in  strength,  and  increased  in  weight 
too  much,  to  allow  of  its  application. 

These  experiments,  however,  being  the  first  successful  attempts  permanently  to  fix  some 
anti-flammable  agents,  may  have  some  interest,  although  they  leave  but  little  hope  that 
the  result  of  fixing  anti-flammable  expedients  will  ever  be  obtained  without  injuring  the 
fabrics. 

By  determining  the  comparative  value,  and  ascertaining  the  difficulties  which  have 
prevented,  till  now,  the  general  use  of  protecting  agents,  the  authors  were  led  to  exclude 
a  number  of  salts  hitherto  proposed,  and  to  advocate  the  adoption  of  sulphate  of  ammonia, 
and  of  tungstate  of  soda,  in  manufactories  of  light  fabrics,  and  in  laundries. 

They  hope,  therefore,  that  the  general  introduction  of  these  salts  will  soon  greatly  re- 
duce danger  and  loss  of  life  through  fire. 

In  the  manufacturing  process  the  weight  increases  at  a  somewhat  higher  rate ;  a  piece 
of  starched  tarlatan,  weighing  about  8  J  oz.,  took  up  about  2  oz.  of  sulphate  of  ammonia 
from  a  10  per  cent,  solution. 

Dr.  Oppenheim  and  Mr.  Versmann  have  received  a  certificate  from  Messrs.  Cochran 
and  Dewar,  of  the  Kiikton  Bleach  Works,  Neilston,  who  bear  witness  to  the  perfect  suc- 
cess of  the  process  for  rendering  muslins  non-inflammable,  by  the  application  of  sulphate 
of  ammonia.  They  have  finished  many  pieces  of  the  finest  muslins  by  this  process,  and 
the  texture  of  the  cloth  is  in  no  way  injured;  while  neither  color  nor  elasticity  is  ma- 
terially changed. 

The  manager  of  the  Queen's  laundry  expresses  entire  satisfaction  with  the  action  of  the 
solution  (namely,  of  tungstate  of  soda)  for  rendering  light  fabrics,  such  as  curtains,  muslin 
dresses,  &c.,  non-inflammable.  After  having  tested  various  salts  and  solutions  intended 
for  the  purpose,  this  is  the  only  one  found  to  be  neither  injurious  to  the  texture  or  color, 
nor  in  any  degree  difficult  of  application  in  the  washing  process.  The  iron  passes  over  the 
material  quite  smoothly,  as  if  no  solution  had  been  employed.  The  solution  increases  the 
stiffness  of  the  fabric,  and  its  protecting  power  against  fire  is  perfect.  The  writer  says  that 
many  specimens  have  been  submitted  to  her  Majesty,  who  was  highly  pleased  with  them, 
and  has  commanded  that  the  solution  be  used  in  the  laundry  for  every  thing  liable  to  danger 
from  fire. 

NAPHTHA.  By  the  term  naphtha,  we  understand  the  inflammable  fluids  produced 
during  the  destructive  distillation  of  organic  substances.  Foi-merly  the  term  was  confined 
to  the  fluid  hydrocarbons,  which  issue  from  the  earth  in  certain  parts  of  the  world,  and  ap- 
pear to  be  produced  by  the  action  of  a  moderate  heat  on  coals  or  bitumens.  The  term  has 
now,  however,  become  so  extended  as  to  include  most  inflammable  fluids  (except  perhaps 
turpentine)  obtained  by  distillation  from  organic  matters.  We  shall  study  the  various 
naphthas  under  the  following  heads: — 


Naphtha  (Boghead  or  Bathgate). 
"         (Bone  or  Bone  Oil). 
"         (Caoutchouc  or  Caoutchouc- 
ine). 


Naphtha  (Coal). 

"         (Native). 
■    "         (Shale). 

"         (Wood). 


For  the  methods  of  preparing  and  purifying  naphthas  in  general,  see  Naphtha,  Coal  ; 

also  PlIOTOGEN. — C.  G.  W. 

NAPHTHA,  Boghkad  or  Bathgate.  Syn.  Photogen,  Paraffine  Oil.  For  several  years 
a  naphtha  has  existed  in  commerce  under  the  above  name.  It  is  now  prepared  on  an  im- 
mense scale  in  various  parts  of  the  Old  and  New  World.  It  was,  we  believe,  at  first  pro- 
cured solely  by  the  distillation,  at  as  low  a  temperature  as  possible,  of  the  Torbanehill 
mineral  or  Boghead  coal,  but  now  it  has  been  ascertained  that  any  cannel  coal,  or  even 
bituminous  shale,  if  subjected  to  the  same  treatment,  will  yield  identical  products. 

Photogen  may  be  recognized  at  once  by  its  low  specific  gravity,  the  ordinary  kinds  (boil- 
ing between  290°  and  480°)  having  a  density  of  about  0-760  ;  whereas  coal  naphtha  cannot 
Ijo  brought  by  any  number  of  rectifications  below  0'850. 

The  less  volatile  portions  of  the  first  runnings  of  photogen  contain  a  considerable 
quantity  of  paraffine,  so  much  so,  indeed,  that  the  oil  is  extensively  used,  under  the  name 
of  paraffine  oil,  for  lubricating  machinery.  A  mixture  of  the  more  and  less  volatile  portions 
is  employed  for  burning. 

Preparation  of  crude  paraffine  oil. 

The  following  is  an  outline  of  the  process  employed  by  Mr.  James  Young.  The  best 
coals  for  the  purpose  are  Parrot,  cannel,  and  gas  coals,  and  especially  the  Boghead  coal. 


NAPHTHA. 


rso 


It  is  well  known  that  the  latter  yields  a  very  large  quantity  of  ash  or  earthy  residuum,  when 
burned  in  an  open  fire  or  distilled  ;  tliis  does  not,  however,  interfere  in  the  least  with  its 
value  as  a  source  of  photogen.  It  is  convenient,  previous  to  placing  tlie  coals  in  the  still, 
to  break  them  into  fragments  of  the  size  of  hen's  eggs,  this  operation  enabling  the  heat  to 
penetrate  more  readily  throughout  the  mass.  The  apparatus  lor  distillation  merely  consists 
of  an  ordinary  gas  retort,  from  the  upper  side  of  which  a  conduction  pipe  passes  to  the 
condensing  arrangement.  The  latter  must  be  moderately  capacious,  and  not  kept  cooler 
than  55^  Fahr.  The  reason  of  this  is,  that  if  too  small  or  too  cool,  the  paraffine  is  liable 
to  accumulate  and  choke  up  the  exit  pipe.  When  the  retort  has  been  closed  in  the 
ordinary  manner,  it  is  to  be  heated  to  a  low  red,  but  not  higher,  until  no  more  volatile 
products  distil  over.  If  the  heat  rises  above  the  temperature  indicated,  a  considerable  loss 
is  incurred,  owing  to  formation  of  too  large  a  quantity  of  olefiant  and  other  gases.  The 
retort  must  be  allowed  to  cool  down  considerably  before  the  insertion  of  a  fresh  charge, 
otherwise  much  is  lost  before  the  joints  are  made  tight. 

Mr.  Young  states  that  instead  of  driving  over  the  whole  of  the  fluid  by  distillation  in  the 
manner  described,  a  portion  may  be  conveyed  at  once  from  the  still  by  having  an  opening 
in  its  lower  part  communicating  with  a  pipe  passing  to  some  convenient  recipient.  By 
this  arrangement,  the  products  from  the  coal  are  removed  from  the  still  the  moment  they 
have  assumed  the  liquid  form.  It  is  preferable,  however,  in  almost  all  cases,  to  distil  the 
hydrocarbons  over  in  the  manner  first  mentioned. 

The  product  of  the  operation  conducted  as  above  is  crude  paraffine  oil.  It  will  some- 
times begin  to  deposit  paralfine  when  the  temperature  has  only  fallen  to  40'.  During  dis- 
tillation a  certain  quantity  of  gas  is  necessarily  produced,  but  it  is  essential  to  economical 
working  that  the  amount  should  be  as  small  as  possible.  To  effect  this,  care  must  be  taken 
not  only  to  use  as  low  a  temperature  as  is  consistent  with  the  distillation  of  the  oil,  but 
also  to  apply  the  heat  gradually  and  steadily.     See  Photogen. 

Purification  of  the  crude  paraffine  oil  for  lubricating  purposes. 

The  oil  is  run  into  a  tank  and  heated  by  a  steam  pipe  to  about  150'  F.  This  causes  the 
water  and  mechanically-suspended  impurities  to  separate.  The  fluid  should  be  permitted 
to  repose  for  about  twelve  hours  before  being  run  off.  The  impurities  and  water  (owing  to 
their  being  specifically  heavier  than  the  paraffine  oil)  remain  at  the  bottom  of  the  settling 
tank. 

The  crude  oil,  after  separation  of  the  mechanically-suspended  impurities,  is  then  to  be 
distilled  in  an  iron  still  attached  to  a  condenser,  kept  at  a  temperature  of  55°,  with  the 
precautions  to  prevent  choking  up,  which  were  previously  described.  The  distillation  is 
conducted  by  the  naked  fire,  until  no  more  cao  be  driven  over.  The  dry  coke-like  mass 
which  remains  in  the  still  is  to  be  removed  before  making  a  fresh  distillation. 

To  each  100  gallons  of  this  distillate,  10  gallons  of  commercial  oil  of  vitriol  are  to  be 
added,  and  the  mixture  is  to  be  well  mixed  for  about  one  hour.  Tlie  apparatus  best  adapted 
for  this  admixture  is  described  in  the  article  Napiitii.!  (Coal).  After  the  thorough  incor- 
poration of  the  oil  and  acid,  the  whole  is  to  be  allowed  to  rest  for  about  12  hours,  to  enable 
the  acid  "sludge"  to  sink  to  the  bottom  of  the  vessel.  The  fluid  is  then  to  be  run  off  into 
another  vessel  (preferably  of  iron),  and,  to  each  100  gallons,  4  gallons  of  caustic  soda,  of 
the  specific  gravity  1'300,  is  to  be  added.  The  soda  and  oil  are  then  to  be  well  incorporat- 
ed by  agitation  for  an  hour,  so  as  to  thoroughly  neutralize  any  acid  which  has  not  settled 
out,  and  also  to  remove  certain  impurities  which  are  capable  of  combining  with  it. 

The  oil  so  purified  is  a  mixture  of  various  fluid  hydrocarbons,  to  be  presently  described, 
holding  in  solution  a  considerable  quantity  of  paralfine.  The  more  volatile  hydrocarbons 
may  be  removed  by  the  following  process: — 

The  purified  paraffine  oil  is  to  be  placed  in  an  iron  still,  connected  with  a  condensing 
arrangement.  The  still  is  then  to  have  run  into  it  a  quantity  of  water,  about  equal  to  half 
the  bulk  of  the  oil,  and  this  distillation  is  to  be  continued  for  12  hours.  It  is  obvious  that 
a  great  portion  of  the  water  would  distil  over,  if  not  replaced  during  the  progress  of  the 
distillation.  It  is  preferable  to  perform  the  distillation  by  means  of  direct  steam.  A  volatile 
clear  fluid  will  distil  over  with  the  water.  The  naphtha  so  procured  is  lighter  than  water, 
and  soon  separates  from  it.  It  contains  little  or  no  paraffine.  The  oil  remaining  in  the 
still  is,  of  course,  richer  in  paraffine  by  the  amount  of  naphtha  removed,  and  the  separation 
of  the  solid  hydrocarbon  is  facilitated  greatly  by  the  process.  The  najjhtha  which  distils 
over  with  the  water  in  the  above  process,  is  the  fluid,  the  chemical  nature  of  which  is  fully 
described  in  this  article.  A  very  volatile  spirit  may  be  extracted  from  it,  by  rectifying  it 
in  the  apparatus  recommended  for  benzole  in  the  article  Naphtha  (Coal). 

The  further  purification  of  the  paralfine  oil  is  managed  as  follows : — After  separation 
from  the  water  it  is  run  off  into  a  leaden  vessel,  and  2  gallons  of  sulphuric  acid  added  for 
each  100  gallons  of  oil.  The  mixture  is  to  be  well  incorporated  for  d  or  8  liours,  after 
which  it  is  allowed  to  remain  quiet  for  24  hours,  in  order  that  the  acid  and  any  combined 
impurities  may  settle  to  the  bottom  of  the  tank.  The  oil  is  then  to  be  carefully  run  off  into 
Vol.  III.— 50 


Y86 


NAPHTHA. 


another  tank,  and  to  each  100  gallons  28  lbs.  of  chalk  ground  with  water  to  a  thin  paste 
are  to  be  added.  The  whole  is  to  be  mixed  together  until  every  trace  of  sulphurous  acid  is 
removed,  and  is  then  kept  at  about  100°  for  a  week,  to  permit  impurities  to  settle.  The 
oil  thus  prepared  is  fit  for  lubricating  purposes,  either  per  se  or  mixed  with  an  animal  or 
vegetable  oil. 

Young's  process  for  separating  paraffine  from  paraffiiie  oil. 

Mr.  James  Young  extracts  paraffine  from  the  oil  prepared  as  above  by  cooling  it  to  30° 
or  40°  Fahr.  The  lower  the  temperature,  the  larger  the  amount  which  crystallizes  out. 
It  may  be  obtained  sufficiently  pure  for  lubricating  purposes  by  merely  filtering  off  and 
squeezing  out  fluid  impurities  from  the  mass  by  powerful  pressure. 

The  paraffine  may  be  purified  further  by  alternate  treatments  at  about  1 50°  Fahr.  with 
oil  of  vitriol  and  caustic  soda.  The  treatments  with  acid  are  to  be  continued  until  the  latter 
produces  no  more  l)lackening.  The  solid  hydrocarbon  is  then  to  be  washed  with  caustic 
soda  until  all  acid  is  removed,  and  then  with  boiling  water.  The  treatment  with  boiling 
water  should  be  performed  several  times. 

The  oil  from  which  the  paraffine  has  been  removed  by  exposure  to  cold  is  by  no  means 
freed  from  the  Avhole  of  the  solid ;  it  is,  in  fact,  a  saturated  solution  of  paraffine  at  the 
temperature  to  which  it  was  exposed.  It  is  sometimes  advantageous,  before  extraction  l)y 
cold,  to  concentrate  the  paraffine  in  the  paraffine  oil,  by  subjecting  the  latter  to  distillation, 
until  one-half  or  two-thirds  of  the  fluid  has  distilled  over  ;  by  this  means  the  yield  of  paraf- 
fine is  proportionately  increased. 

The  amount  of  .solid  matter  distilling  over  with  naphthas  may  be  seen  by  consulting 
the  results  obtained  by  MM.  Warren  de  la  Rue  and  Hugo  Miiller,  in  their  fractional  distillation 
of  Rangoon  tar.  It  is  to  be  observed  that  solid  hydrocarbons  differ  in  the  degree  to  which 
they  pass  over  with  the  vapor  of  fluid  hydrocarbons.  Thus  while  pyrene  and  chrysene  only 
appear  among  the  very  last  products  of  the  distillation  of  coal  at  high  temperature,  naphtha- 
line will  often  distil  over  at  very  moderate  temperatures  in  presence  of  volatile  fluid  hydro- 
carbons. The  author  of  this  article  has  repeatedly  seen  considerable  quantities  distil  over  in 
a  current  of  steam  at  the  pressure  of  the  atmosphere,  and  consequently  at  212^  The  facility 
with  which  solid  hydrocarbons  pass  over  in  the  vapor  of  volatile  fluids,  depends  not  only 
upon  their  boiling  points,  but  also  to  some  extent  upon  special  tendencies  varying  with  the 
nature  and  state  of  admixture  or  combination  of  the  substances  operated  on. 

On  the  chemical  nature  of  the  fluid  hydrocarbons  constituting  Boghead  naphtha. 

It  has  been  said,  in  the  above  condensed  account  of  the  process  for  preparing  paraffine 
oil  from  coal,  that  when  the  crude  oil  is  rectified  with  water,  a  clear  transparent  naphtha  is 
obtained.  This  fluid,  as  found  in  commerce,  is  by  no  means  of  constant  quality.  By 
quality,  we  mean  the  power  of  distilling  between  given  limits  of  temperature.  Pome  kinds 
are  of  about  the  same  degree  of  volatility  as  commercial  benzole,  while  others  distil  at  near- 
ly the  same  temperatures  as  common  coal  naphtha.  The  hydrometer  is  not  a  safe  guide  in 
choosing  this  naphtha  ;  this  arises  from  the  fact  that  photogens,  of  very  different  degrees  of 
volatility,  have  almost  the  same  densities.  The  safest  plan  is  to  put  tlie  fluid  into  a  retort, 
having  a  thermometer  in  the  tubulature,  and  distil  the  contents  almost  to  dryness.  The 
careful  observation  of  the  range  of  the  mercurial  column  during  the  operation  is  the  best 
mode  of  ascertaining  the  quality  of  the  fluid. 

The  more  volatile  portions  which  distil  over  with  water,  arc  free  from  solid  bodies,  and 
consist  of  a  mixture  of  fluids  belonging  to  three  series  of  homologous  hydrocarbons,  namely, 

The  benzole  series ; 

The  defiant  gas  or  C^U"  series ;  and 

The  radicals  of  the  alcohols. 

As  no  works  on  chemistry  contain  any  directions  for  the  proximate  separation  of  com- 
plex mixtures  of  hydrocarbons,  the  following  description  of  the  method  adopted  by  the 
author  of  this  article  for  the  separation  of  the  substances  contained  in  Boghead  naphtha 
may  be  useful.  It  is  necessary,  in  the  first  place,  to  determine  whether  each  sul)stance  is 
to  be  obtained  in  a  state  of  absolute  purity,  or  whether  it  is  merely  desired  to  obtain  the 
various  series  distinct  from  each  other.  In  the  process  given,  it  will  be  supposed  that  the 
individual  hydrocarbons  arc  required  in  a  state  of  purity,  because  it  is  easy  for  the  operator 
to  leave  out  any  part  of  the  method  which  may  be  unnecessary  under  the  particular  circum- 
stances of  the  case.  The  first  step  is  to  obtain  constant  lioiling  points,  fur  it  must  l)e 
remembered  that  if,  when  any  organic  fluid  is  subjected  to  distillation  with  a  thennometer  in 
the  tubulature  of  the  retort  or  still,  the  mercury  continues  to  rise  as  the  fluid  comes  over, 
it  is  at  once  demonstrated  that  the  substance  distilling  is  not  homogeneous.  In  order  to 
obtain  the  fluids  of  constant  boiling  point,  it  is  essential  to  subject  them  to  a  complete  seiies 
of  fractional  distillations.  This  is  an  operation  involving  great  labor,  so  much  so,  that  iti 
investigating  Boghead  naphtha,  upwards  of  one  thousand  distillatiorts  were  made  before  tolera- 
bly constant  boiling  points  were  secured.  In  order  to  perform  the  operation  successfully, 
two  series  of  bottles  are  required,  one  for  the  series  being  distilled,  and  the  other  for  the  series 


NAPHTHA.  787 

distilling.  As  many  bottles  are  necessary  as  there  are  lO-degree  fractions  to  be  obtained. 
Tlius,  supposing  the  fluid,  when  first  distilled,  came  over  between  luo  and  200",  and  it  has 
been  determined  to  obtain  10-degree  fractions,  the  receiver  is  to  be  charged  for  every  Mf 
that  the  mercury  rises.  Thus  10  bottles  will  be  required  for  the  fractions  distilling,  and  tlie 
same  number  for  the  fractions  being  distilled  into.  The  operation  will  be  commenced  by 
putting  the  original  fluid  (dried  carefully  with  cliloride  of  calcium  or  sticks  of  potashj  into 
a  retort  capable  of  holding  at  least  half  as  much  more  fluid  as  the  quantity  inserted. 
Through  the  tubuluturc  passes  a  pierced  cork,  sujiporting  a  thermometer,  the  lower  end  of 
which  should  not  dip  into  the  fluid.  To  the  neck  of  the  retort  is  adapted  a  good  condens- 
ing arrangement,  so  placed  that  the  bottles  can  be  placed  beneath  the  e.xit  pipe.  All  the 
bottles  having  blank  paper  labels  attac'aed,  the  distillation  is  to  be  commenced.  The  first 
signs  of  distillation  are  to  be  watched  for,  but  no  fluid  is  to  be  separately  received  as  an 
individual  fraction  until  boiliug  has  commenced.  As  soon  as  it  is  found  that  the  mercury 
indicates  10'  more  than  the  temperature  at  which  the  distillation  commenced,  the  bottle  is 
to  be  changed,  and  so  on  at  every  10^.  When  the  whole  fluid  is  distilled  aw.iy,  a  small 
retort  is  to  be  taken,  capable  of  well  holding  each  10-degree  fraction,  without  fear  of  any 
thing  boiling  over.  Suppose  the  first  fraction  of  the  first  distillation  came  over  between  lOO" 
and  110\  it  is  to  be  placed  in  the  retort,  and  the  distillation  carried  on  as  befoie.  But  it 
will,  in  almost  every  instance,  be  found  that  the  boiling  point  will  have  been  reduced  80' 
or  40'  by  the  removal  of  the  fluids  of  higher  boiling  point.  Under  any  circumstances, 
however,  the  distillate  is  to  be  received  in  bottles,  and  labelled  with  the  boiling  point  and  the 
number  of  the  rectification.  When  all  the  first  10-degree  fraction  has  distilled  away  into  tlie 
second  series  of  bottles,  the  next  is  to  be  operated  on,  and  so  on.  By  tliis  means  only  two 
series  of  bof^les  are  ever  being  used  at  once,  viz.,  the  series  being  distilled,  and  the  series 
being  distilled  ixto.  Many  fluids  may  be  obtained  of  steady  boiling  point  by  15  or  l(i  recti- 
fications, involving,  in  the  case  of  10  fractions  in  each  series,  at  least  150  distillations. 
But  most  complex  organic  fluids,  such  as  naphthas,  have  a  much  wider  range  of  boiling 
point  than  100'.  Boghead  naphtha,  for  example,  commences  at  about  2S0  F.,  and  rises 
above  500'.  Bat  in  the  second  distillation,  the  first  fraction,  instead  of  distilling  at  289°, 
came  over  at  250',  the  depression  of  Ijoiling  point  being  nearly  40".  By  proceeding  in  this 
manner  six  times,  a  fraction  was  obtained  boiling  at  210'.  When  a  10-degree  fraction  no 
longer  splits  up  during  distillation,  tliat  is  to  say,  when  it  comes  over  almost  between  the 
s.ime  points  at  which  it  last  distilled,  it  will  be  proper  to  commence  the  separation  of  the 
various  substances  present  in  each  fraction.  Before  doing  this,  it  is  often  advisable  to  make 
a  few  preliminary  experiments,  with  the  view  of  ascertaining  the  nature  of  the  fluids 
present.  The  more  volatile  portions  may  be  tested  for  benzole  by  converting  them  into 
aniline  in  the  method  given  in  the  article  Bkxzole.  The  simplest  way  of  detecting  the 
C 'H"  series  (liomologous  with  olefiant  gas)  will  be  by  ascertaining  whether  the  naphtha  is 
capable  of  decolorizing  weak  bromine  \\;ater.  Supposing  the  presence  of  these  to  have  been 
demonstrated,  the  complete  separation  of  the  hydrocarbons  may  be  effected  as  follows: — 
Four  or  five  ounces  of  bromine  are  to  be  placed  in  a  Lirge  flask,  capable  of  being  closed 
with  a  well  fitting  stopper.  About  8  volumes  of  water  are  then  added,  and  the  naphtha  of 
the  most  volatile  fraction  is  to  be  poured  in  by  very  small  portions,  the  contents  of  the  flask 
being  well  shaken  after  each  addition. 

By  this  mode  of  proceeding,  the  dark  color  of  the  bromine  will  gradually  fade  and  finally 
disappear.  In  order  to  insure  a  complete  reaction,  it  is  better  at  this  stage  to  add  a  little 
more  bromine,  until  the  color  is  permanent  after  shaking.  A  little  mercury  is  now  to  be 
poured  in,  and  agitated  with  the  fluids  in  the  flask,  to  remove  all  excess  of  bromine.  The 
oily  bromine  compound  is  now  to  be  separated,  by  means  of  a  tap  funnel,  from  the  mercury 
and  water,  and  digested  witli  chloride  of  calcium  until  every  trace  of  water  is  removed. 
The  dry  brominated  oil  is  now  to  be  distilled,  when  the  radical  and  benzole  series  of  hydro- 
caibons  will  distil  away,  leaving  the  brominated  oil,  which  may  then  be  distilled  into  a 
vessel  by  itself.  The  next  step  will  be  to  separate  the  radicals  from  the  benzole  series. 
For  this  purpose  long-necked  assay  flasks  are  necessary.  Into  one  of  these  vessc'ls,  of  3  or 
4  ounces  capacity,  2  drachms  of  nitric  acid  should  be  poured  ;  1  drachm  of  the  naphtha  is 
then  to  be  adiled  by  very  small  portions,  the  flask  being  ke])t  cool  by  immersion  in  cold 
water.  It  is  essential  during  the  wliole  time  to  keep  the  flask  in  active  motion,  in  order  to 
bring  the  hydrocarbon  and  acid  into  close  contact,  and  also  to  cool  the  contents.  If  this 
last  precaution  be  neglected  a  violent  reaction  will  occur  and  cause  tiie  loss  of  the  greater 
portion  of  the  fiuid.  When  the  whole  of  the  drachm  of  acid  has  been  addi'd,  and  it  is 
.found  that  the  temperature  no  longer  rises  on  removing  the  flask  from  tlie  cold  water,  the 
product  is  to  he  poured  into  a  narrow  and  conical  gl:u<s,  and  allowed  to  re|)ose  until  the 
hydrocarbon,  unacted  on,  rises  to  the  surl'aee  in  the  form  of  a  transparent  l>riHiant  green 
fluid.  Tlie  fluid  lielow  is  then  to  be  removed  by  means  of  a  pipette,  furnished  at  tlie  U])per 
end  with  a  hollow  elastic  ball  of  vuleajiized  caoutchouc.  By  this  means  suction  with  the 
lips  becomes  unnecessary,  and  the  vapors  of  hyponitric  acid  are  prevented  from  irritating  the 
lungs.     The  indifferent  hydrocarbon — that  is,  the  fluid  unacted  on  by  the  acid — is  as  yet 


788 


NAPHTHA. 


by  no  means  pure ;  it  obstinately  retains  traces  of  the  benzole  and  C"H»  series.  It  is,  there- 
fore, to  be  transferred  to  a  flask  furnished  with  a  well  fitting  stopper,  and  treated  -with  nitric 
acid  (spec.  grav.  To)  a  considerable  number  of  times.  This  second  treatment  may,  without 
danger  of  any  explosive  reaction,  be  made  upon  one  or  two  ounces  of  the  partially  purified 
hydrocarbon.  When  it  is  found  that  the  sejjurated  nitric  acid  no  longer  produces  milkiness 
on  being  thrown  into  water,  it  may  be  assumed  that  the  benzole  and  C"!!"  class  of  hydro- 
carbons are  entirely  removed.  When  the  treatment  with  acid  has  been  repeated  a  suffi- 
cient number  of  times,  the  fluid  is  to  be  placecl  in  a  clean  flask  and  well  agitated  with  a 
solution  of  caustic  potash,  which  will  remove  the  nitrous  vapors  which  are  the  cause  of  the 
green  color.  The  j>urified  hydrocai-bon  is  then  to  be  separated  by  a  tap  funnel  from  the 
water,  and  dried  by  digestion  with  sticks  of  caustic  potash.  If  it  be  desired  to  obtain  the  radi- 
cal in  a  state  of  absolute  purity,  it  must  be  distilled  three  or  four  times  over  metallic  sodium. 
The  indifferent  hydrocarbons  obtained  by  the  above  process  are  colorless  mobile  fluids, 
having  an  odor  somewhat  resembling  the  flowers  of  the  white  thorn.  They  are  very  vola- 
tile, even  at  low  temperatures,  and  have  an  average  density  of  about  0-716.  When  the 
fractions  with  proper  boiling  points  have  l)een  selected,  it  will  be  found  that  tiiey  corre- 
spond in  specific  gravity,  percentage  composition,  and  vapor  density  with  the  radicals  of  the 
alcohols,  as  will  appear  by  the  following  table,  where  the  experimental  results  obtained  by 
the  author  of  this  article  in  his  examination  of  Boghead  naphtha  are  compared  with  the 
numbers  found  by  other  observers  with  the  radicals  obtained  by  treatment  of  the  hj-driodic 
ethers  by  sodium,  and  also  by  the  electrolysis  of  the  fatty  acids. 

Comparative  Table  of  the  Physical  Properties  of  the  Alcohol  Radicals,  as  ohtaincd from 
Boghead  Naphtha,  with  those  procured  from  other  sources. 


Formul.-B. 

Boiling  Points,  Fahr. 

Radicals. 

Frankland. 

Kolbe. 

Wurtz. 

Brazier  and 
Gosslett. 

C.  G.Williams. 

Propvle        .        .       - 

Buty'le 

Ainyle 

C.iproyle 

0121114 
C"H18 
C20H22 
C24H26 

311° 

226-4° 

2'22-8' 
316-4 
395-6 

154-4° 
2462 
SlS-2 
395-6°            895-6        ! 

1 

Densities. 

Vapor  Densities. 

Radicals. 

Formula-. 

Frankland. 

Kolbe,         Wurtz, 
at  64-4'.       at  3-2'. 

C.  G.Williams, 
at  64-4'. 

Frankland.', 
:    at  51-8.°    ;Ko'be 

Wuriz 

C.  G.  Wil- 
liams. 

Theory. 

Propvle 
Buty'le 
Amyle 
Capfoyle 

Ci2Hi« 

C16H18 

C-Jl)II22 
C24H26 

4-S99 

0-6940      0-7057 

-  0-7413 

-  0-7574 

0-6745 
0-6945 
0-7365 
0-7563 

0-7704 

1  -     - 
4  053 

4-070 
4-956 
5-9S3 

2-96 
3-SS 
4  93 
5-S3 

2-97 
3  94 
491 
5-S7 

It  has  been  said  that  the  above  hydrocarbons  distilled  away  from  the  bromine  compound 
in  company  with  othere  which  were  removed  by  treatment  with  nitric  acid.  It  was  sub- 
sequently found  that  the  products  formed  by  the  action  of  the  acid  were  nitro-compounds 
belonging  to  the  benzole  series.  The  bromine  compound  contains  the  C"H°  series  of  hydro- 
carbons, the  individual  member  being  determined  by  the  boiling  point  of  the  fraction 
selected  for  experiment.  If  we  select  that  portion  boiling  steadily  between  1G0°  and  170°, 
we  shall  have  a  bromine  compound  of  the  formula  C''*H'^Br° ;  but  if  the  boding  point  of  the 
naphtha  lies  between  180°  and  190°,  the  bromine  compound  will  be  C^H^lir^.  It  is  ex- 
ceedingly remarkable  that  if  either  of  these  substances  be  treated  alternately  with  alcoholic 
potash  and  sodium,  the  original  hydrocarbon  is  regenerated.  By  the  mode  of  operating 
indicated  above  it  is  possible,  therefore,  to  obtain  two  out  of  the  three  series  of  hydrocarbons 
in  a  pure  state.  The  third,  namely  the  benzole  series,  must  be  recognized  bj  obtaining 
products  of  decomposition. 

The  acids  and  bases  accompanying  the  hydrocarbons  in  Boghead  naphtha  have  not  yet 
been  fully  investigated  ;  it  has,  however,  been  ascertained  that  certain  members  of  the 
phenole  series  of  acids  and  pyridine  cla.s3  of  bases  are  always  present.  The  quantities 
present  in  the  naphtha  of  commerce  are  small  in  consequence  of  the  purification  of  the  fluid 
by  the  agency  of  oil  of  vitriol,  followed  by  a  treatment  with  caustic  soda. — C.  G.  W. 

NAPHTHA,  Bonk.  Syn.  Bone  Oil ;  Dippel's  Animal  Oil.  This  fluid  is  procured  in 
large  quantities  during  the  operation  of  distilling  bones  for  the  preparation  of  animal  char- 
coal. The  hydrocarbons  of  bone  oil  have  not  as  yet  been  examined,  but  it  has  been  found 
that  the  benzole  series  are  present,  accompanied  by  large  quantities  of  basic  oils.  The  acid 
portions  are  also  uninvestigated.  The  bases  have  been  very  fully  studied  by  Dr.  Anderson, 
who  discovered  in  bone  oil  the  presence  of  no  less  than  ten  bases,  several  of  them  being 
quite  new. 

The  odor  of  bone  oil  is  exceedingly  offensive  and  difficult  of  removal.  It  does  not  arise 
entirely  from  the  presence  of  the  powerfully  Bmelling  bases,  for  even  after  repeated  treat- 


NAPHTHA, 


789 


ment  with  concentrated  acids  it  retains  its  repulsiveness.  This  is  partly  owing  to  the  pres- 
ence of  some  unknown  neutral  nitrogenous  bodies.  When  a  slip  of  deal  wood  is  moistened 
with  hydrochloric  acid  and  held  over  a  vessel  of  crude  bone  oil,  it  rapidly  acquires  a  deep 
crimson  tint.  This  is  in  consequence  of  the  presence  of  the  extraordinary  basic  substance 
pyrrol.  The  latter,  when  in  a  crude  state,  possesses  a  most  disgusting  smell,  so  much  so, 
that  the  offensiveness  of  bone  oil  was  at  one  time  mainly  attributed  to  its  presence.  It 
has,  however,  been  recently  discovers',  that  pyrrol  when  perfectly  pure  has  a  most  fragrant 
and  delightful  perfume,  somewhat  recalling  that  of  chloroform,  but  still  more  pleasing. 

The  basic  portion  of  bone  oil  may  be  extracted  by  shaking  it  up  with  moderately  strong 
oil  of  vitriol.  This  must  be  done  with  precaution,  as  large  quantities  of  gases  are  evolved, 
consisting  of  carbonic  acid,  hydrosulphuric  and  hydrocyanic  acids.  The  liuid  when  permit- 
ted to  repose  separates  into  two  layers,  the  upper  being  the  purified  oil,  and  the  lower  the 
acid  solution  of  the  bases.  The  latter  being  separated  is  to  be  distilled  until  about  one-third 
has  passed  over.  This  distillate  will  contain  the  chief  portion  of  the  pyrrol.  The  head  of 
the  still  is  then  to  be  removed  and  the  fluid  boiled  for  some  time,  to  remove  the  last  trace. 
The  acid  solution,  after  filtration  through  charcoal,  is  to  be  supersaturated  with  lime  and 
distilled.  The  distillate  contains  the  whole  of  the  bases.  The  apparatus  should  be  so 
arranged  that  those  bases  which  are  excessively  volatile,  and  consequently  come  over  as 
gases,  may  be  received  in  hydrochloric  acid.  The  hydrochloric  solution  and  the  oily  bases 
are  to  be  examined  separately.  The  former  is  to  be  evaporated  carefully  to  the  crystallizing 
point  and  then  allowed  to  cool.  By  this  means  the  ammonia  may  be  removed  by  crystalU- 
zation  as  chloride  of  ammonium. 

When  no  more  sal-ammoniac  can  be  obtained  by  crystallization,  the  mother  liquid  is  to 
be  treated  with  potash,  in  an  apparatus  so  arranged  that  any  gaseous  products  evolved  may 
be  collected  in  hydrochloric  acid.  The  retort  must  have  a  thermometer  in  the  tubulature 
to  enable  the  temperature  to  be  properly  regulated.  All  the  bases  distilling  below  212° 
are  to  be  received  in  hydrochloric  acid,  and  their  presence  demonstrated  by  converting  them 
into  platinum  salts,  and  fractionally  crystallizing.  The  bases  distilling  above  212""  are  to 
be  separated  by  fractional  distillation.  An  examination  of  the  hydrochloric  solution  will, 
according  to  Dr.  Anderson,  demonstrate  the  presence  of  methylamine,  propylamine,  butyl- 
aniine,  and  amylamine.  The  following  table  contains  the  names  and  physical  properties  of 
the  bases  which  are  contained  in  that  portion  of  the  basic  oil  which  distils  above  212'. 
The  amylamine,  and  even  the  propylamine,  can  be  separated  from  the  basic  oils  by  frac- 
tional distillation,  instead  of  the  fractional  crj'stallization  of  platinum  salts,  but  the  latter 
involves  less  labor. 

Table  of  the  Physical  Properties  of  the  Pyridine  Series  of  Bases. 


Base. 

Formula. 

Boiling  Point 

Density  at  32°. 

Yapor  Density. 

Experiment. 

Calculation. 

Pyridine         -         -        C'H^X 
Picoline          -         -  '     C"H"N 
Lutidine         -         -  !     C"H'N 
Collidine        -        -  i     C'=H"N 

242° 
275° 
310° 
356° 

0-9858 
0-9613 
0-9467 
0-9439 

2-916 
3-290 
3-839 

2-734 
3-214 
3-699 
4-137 

Bone  oil  will  not  become  very  valuable  as  a  naphtha  for  general  purposes  until  some 
cheap  method  of  removing  its  odor  has  been  discovered.  The  Oleum  animale  dipcllii  of 
the  older  chemists  and  pharmaceutists  was  prepared  by  distilling  bones ;  it  was  very  similar 
in  properties  to  bone  oil. — C.  G.  W. 

NAPHTHA  FROM  C.\ouTCiiouc.  Syn.  Caoutchoucine ;  Caoutchine.  Caoutchouc,  by 
destructive  distillation,  yields  several  hydrocarbons,  the  accounts  of  which  are  contradictory. 
By  repeated  rectifications  they  may  be  separated  into  fluids  of  .steady  boiling  points.  The 
late  Dr.  (ircgory  succeeded  in  obtaining  a  fluid  hydrocarbon  from  caoutchouc  which  distill- 
ed at  96',  but  when  treated  with  sulphuric  acid,  and  the  fluid  separated  by  means  of  water, 
another  hydrocarbon  was  obtained  boiling  at  428".  It  is  most  probable,  however,  that  the 
true  composition  of  caoutchoucine  has  not  yet  been  made  out.  This  will  appear  by  con- 
sulting the  analyses  yet  made,  many  of  them  indicating  too  low  a  hydrogen  for  the  C"II" 
series,  and  more  nearly  approximating  to  n  (C'lP).  The  author  of  this  article  is  engaged 
.in  a  new  examination  of  these  hydrocarbons.  It  is  quite  plain,  however,  that  caoutchine 
is,  in  every  sense  of  the  term,  a  naphtha.  Caoutchine  is  one  of  the  best  solvents  known 
for  india-rubber. — C.  (r.  W. 

X APHTHA,  Coal.  Ordinary  coal  naphtha  is  procured  by  the  distillation  of  coal  tar. 
The  latter  is  placed  in  large  iron  stills,  holding  from  800  to  1,500  gallons,  and  distilled  by 
direct  steam.  As  soon  as  specific  gravity  of  the  distillate  rises  to  0-010,  the  naphtha  is 
pumped  into  another  still,  and  distilled  with  direct  steam  until  the  distillate  again  becomes 
of  the  density  O-'.Hn.     It  then  constitutes  what  is  termed  "rough  naphtha." 


790 


iJ  APHTHA. 


The  residue  obtained  in  the  first  distillation  is  run  off  into  cisterns  or  tar  ponds  to  allow 
of  the  removal  of  the  water.  This  residue  is  called  boiled  tar.  Pitch  oil  may  be  obtained 
from  it  by  distillation  with  the  naked  lire,  every  1,000  gallons  will  yield  about  320  gallons 
of  pitch  oil.  The  residue  of  pitch  in  the  still  is  run  out  while  in  a  melted  state.  The  rough 
coal  naphtha  contains  a  great  number  of  impurities  of  various  kinds,  the  principal  cause  of 
the  foul  odor  being  the  organic  bases  described  in  the  article  Naphtha,  Boxe.  To  remove 
these  the  naphtha  is  transferred  to  large  cylindrical  vessels  lined  with  lead.  These  vessels 
contain  a  vertical  axis  passing  down  them,  supporting  blades  of  wood  covered  with  lead, 
and  pieiced  with  holes.  The  axis  or  shaft  has,  at  its  upper  end,  a  crank  to  enable  it  to  be 
rotated.  The  naphtha  having  been  run  into  the  vessel,  sulphuric  acid  is  added,  and  the 
shaft  with  its  blades  made  to  revolve.  By  this  means  the  naphtha  and  acid  are  brought  into 
intimate  contact.  The  whole  is  then  allowed  to  settle,  and  the  vitriol  which  has  absorbed 
most  of  the  impurities,  and  acquired,  in  consequence,  a  thick  tarry  consistence,  is  run  off". 
Tills  acid  treacly  matter  is  known  in  the  works  as  "  sludge."  The  naphtha  floating  above 
the  sludge  is  then  treated  a  second  time  with  acid,  if  the  naphtha  be  required  of  good 
quality.  During  the  process,  the  naphtha  acquires  a  sharp  smell  of  sulphurous  acid,  and 
retains  a  certain  amount  of  sulphuric  acid  in  solution.  The  next  process  is  to  treat  it  with 
solution  of  caustic  soda  to  remove  these  impurities.  This  may  be  effected  in  an  apparatus 
similar  to  the  first.  The  naphtha,  after  removal  of  the  caustic  liquor,  is  next  run  off  into  a 
still,  and  rectified;  it  then  fbims  the  coal  naphtha  of  commerce.  The  ordinary  naphtha 
of  commerce  is  often  very  impure,  owing  to  insufficient  treatment  with  oil  of  vitriol.  The 
author  of  this  article  has  obtained  from  one  gallon  of  commercial  naphtha  as  much  as  one 
and  a  half  ounces  of  the  intensely  odorous  picolinc,  mixed  with  certain  quantities  of  other 
bases  of  the  same  series,  and  also  traces  of  aniline. 

In  describing  coal  naphtha,  we  shall  not  confine  ourselves  to  the  description  of  those 
substances  which  come  over  in  distillation  between  any  given  temperature,  but  shall  take 
a  cursory  review  of  the  nature  and  properties  of  most  of  the  substances  produced  by  the 
distillation  of  coal  tar.  It  will  be  unnecessary  here  to  enter  into  a  minute  description  of 
the  acids  existing  in  coal  tar,  inasmuch  as  they  have  already  been  treated  of  in  the  article 
Carbolic  Acid. 

On  the  basic  constituents  of  coal  naphtha. — Coal  tar  is  particularly  rich  in  bases.  They 
are  found  accompanying  all  the  fluid  naphthas  and  oils,  and  probably  cannot  be  separated, 
by  distillation  alone,  from  any  of  the  hydrocarbons  of  coal  naphtha  except  benzole.  It  is 
highly  remarkable  that  while  coal  tar  yields  all  the  pyridine  series  of  bases  found  in  bone 
oil,  no  traces  of  the  alcohol  series  have  yet  been  discovered.  At  the  time  that  the  author 
of  this  article  commenced  his  experiments  on  the  coal  naphtha  bases,  there  were  only  three 
known  to  be  present,  namely,  aniline,  ehinoline,  and  pieoline.  The  two  former  were  dis- 
covered in  coal  tar  by  Runge,  who  called  them  kyanol  and  leukol.  Pieoline  was  discovered 
by  Dr.  Anderson,  of  Glasgow.  The  discovery  was,  at  the  time,  of  great  value,  it  being 
the  first  instance  on  record  of  isomerism  among  volatile  bases.  The  number  of  isomeric  bases 
now  known  is  very  great,  and  fresh  instances  are  becoming  known  every  day.  The  follow- 
ing are  the  bases  known  to  be  present  in  coal  tar,  with  their  formulae.  They  will  be  found 
mentioned  under  their  names  in  this  work.  The  physical  properties  of  the  pyridine  series 
are  given  under  Naphtha,  Boxe. 


Pyridine 
Pieoline 
Lutidine 
Collidine 


-  C'"!!  =N 

-  C'-II  "N 

-  cm  "N 

-C""TI"N 
Pvrrol    - 


Chinoline 
Lepidine 
Cryptidine 
Aniline 
-  CnPN. 


-  C"H  'N 

-  C^°H  ^V 
C"H"N 

-C'^'N 


On  the  hydrocarbons  of  coal  naphtha — The  following  are  the  principal  constituents  of 
those  coal  naphthas  the  boiling  points  of  which  range  between  190 '  and  350° : 


Base. 

Formula. 

Boitln?  Point. 

Specific  Gravity. 

Benzole  - 
Tolnolc    - 
Xylole     - 
Cumolo    - 
Cymole    -         -         - 

C'-IP 
C20jgi4 

177° 
230° 
259° 
304° 
347° 

0-850  at  60° 
0-870 

0-861  "  57° 

The  fluid  hydrocarbons  boiling  above  this  point  have  not  been  well  studied.  Ordinary 
coal  naphtha,  in  addition  to  the  above  hydrocarbons,  contains  traces  of  the  homologues  of 
olefiant  gas,  alluded  to  in  the  article  Naphtha,  Boghead. 

All  the  above-mentioned  hydrocarbons  may  be  separated  from  each  other  by  careful  and 
sufficiently  numerous  fractional  distillations.  It  is  proper  before  considering  them  as  pure, 
to  shake  them  up  several  times  with  oil  of  vitriol,  and,  after  well  washing  first  with  water, 


NAPHTHA. 


791 


and  afterwards  with  an  alkaline  solution,  to  dry  them  very  carefully  with  chloride  of  calcium 
or  sticks  of  potash.  It  will  be  observed  that  in  the  above  table  the  specific  gravities  of  the 
hydrocarbons  are  not  in  harmony ;  this  arises  from  the  iluids  upon  which  the  experiments 
were  made  not  having  all  been  procured  from  the  same  source  ;  for  it  has  been  found  that 
the  same  bodies,  as  procured  from  different  sources,  often  present  small  but  appreciable 
differences  in  odor,  density,  boiling  point,  and  other  physical  properties. 

The  benzole  of  coal  naphtha  may  almost  entirely  be  separated  by  distilling  in  an  appara- 
tus first  devised  for  the  purpose  by  Mr.  C.  B.  Mansfield.  The  annexed  figures  from  my 
"Handbook  of  Chemical  Manipulation,"  illustrate  the  vessels  I  am  in  the  habit  of  employ- 
ing for  the  purpose.  Fig.  464  consists  of  a  copper  or  tinned  iron  still,  a,  holding  about  two 
gallons.  The  flange,  b  6,  is  merely  to  support  the  apparatus  in  the  ring  of  a  gas  or  charcoal 
furnace,  preferably  the  former.  A  wide  worm,  c  <■,  passes  through  the  top  of  the  still  into 
a  water-tight  cistern,  d  d.  The  worm  ends  in  a  discharge  pip.e,  e.  The  latter  is  to  be  at- 
tached to  a  common  worm-tub  containing  cold  water.  The  crude  benzole,  or  coal  naphtha, 
is  to  be  placed  by  means  of  the  opening/ into  the  still,  and  all  the  joints  of  the  apparatus 
being  closed,  and  effectual  condensation  insured,  the  fire  is  to  be  lit.  The  naphtha  soon 
begins  to  boil,  but  nothing  comes  over,  because  the  water  'va.d  d  effects  condensation.  In 
a  short  time,  however,  the  water  in  dd  begins  to  get  warmer,  and,  as  soon  as  IVJ"  is 
reached,  benzole  begins  to  come  over,  and  is  perfectly  condensed  in  a  second  worm,  kept 
cold  by  means  of  water.  It  is  plain  that  as  the  fluids  of  higher  boiling  points  begin  to  come 
over,  the  water  '\xi  d  d  will  boil,  but  distillation  then  ceases  entirely.  The  reason  of  this  is, 
that  nothing  can  make  the  head  c  c  hotter  thau  212^,  because  of  its  being  surrounded  with 
water.  All  hydrocarbons  that  are  not  volatile  at  212°  are  consequently  condensed  there, 
and  fall  back  into  a.  The  benzole  distilling  over  is  quite  pure  enough  for  all  ordinary 
purposes.  It  may,  if  required  very  pure,  be  rectified  a  second  time  in  the  same  apparatus, 
taking  care  that  the  head  does  not  get  hotter  than  180°  or  190''.  If  the  benzole  is  wanted 
absolutely  free  from  its  accompanying  hydrocarbons,  it  must  be  purified  by  freezing.  For 
this  purpose  the  rectified  benzole  is  to  be  placed  in  a  thin  glass  or  metal  vessel,  and  sur- 
rounded with  snow  or  pounded  ice  mixed  with  salt.  The  whole  apparatus  is  to  be  surround- 
ed with  sawdust  and  covered  with  woollen  cloths  to  prevent  access  of  heat.  As  soon  as  the 
benzole  is  frozen,  it  is  to  be  placed  in  a  funnel  and  allowed  to  drain.  The  solid  mass  when 
thawed  is  pure  benzole.  By  this  mode  of  proceeding,  a  considerable  quantity  of  fluid  is 
always  accumulated  which  refuses  to  freeze  and  yet  boils  at  the  proper  temperature  for 
benzole.  I  have  found  it  to  contain  a  small  quantity  of  the  C"!!"  series  of  hydrocarbons 
(homologous  with  olefiant  gas).  Mr.  Church  states  it  to  contain  benzole  in  a  peculiar  con- 
dition ;  he  calls  it  parabenzole.  The  presence  of  the  C"!!"  series  may  always  be  proved  by 
the  readiness  with  which  the  fluid  decolorizes  bromine  water. 


464 


465 


A  simpler  form  of  apparatus  for  rectifying  benzole,  and  one  that  answers  almost  as 
well,  is  that  represented  in  fig.  465.  It  will  be  seen  that  the  worm  c  c  of  fig.  464  is 
replaced  by  a  straight  tube.     The  mode  of  use  is  precisely  the  same. 

Where  the  benzole  is  to  be  extracted  from  coal  naphtha  on  the  large  scale,  the  follow- 
ing apparatus  will  be  found  convenient: — The  boiler  a  «,  {-fig.  400)  surrounded  bv  a  .steam 
jacket,  is  connected  at  its  upper  extremity  with  a  head,  h\  answering  to  the  worm  c  in  AV/. 
404.  The  head  plays  into  the  worm  tub  (/ ;  the  benzole  being  conveyed  by  the  exit  pipe 
e  to  the  reservoir  or  close  tank  in  whicii  it  is  to  be  stored.  The  tub  c  c  c  c  contains  water 
to  condense  the  hydrocarbons  which  arc  to  be  removed  from  the  benzole.  In  order  to 
save  time  it  is  convenient  at  the  commencement  of  the  operation  to  heat  the  water  m  c cc  c 
to  about  170°  ;  this  is  effected  by  means  of  the  steam  pipe  I  I  /,  which  is  connected  with 
the  boiler/.  Tlie  steam  is  admitted  to  the  jacket  of  the  still  by  means  of  the  pipe  g.  Tlie 
steam  can  bo  regulated  or  stopped  altogether  by  means  of  the  stop-cock  n.  The  cock  m  is 
to  regulate  the  admission  of  steam  to  the  vessel  c  c  c  c.     The  man-hole  is  represented  at  k. 


Y92 


NAPHTHA. 


A  small  cock  to  allow  the  condensed  water  in  the  jacket  to  be  run  off,  is  seen  at  i.  Unless 
the  naphtha  is  of  the  best  quality  the  benzole  will  be  dithcult  to  extract  by  the  heat  of  the 
jacket  alone.     It  will  then  be  necessary  to  send  direct  stcain  into  a  a.     When  no  more 


466 


benzole  comes  over,  the  remaining  naphtha  is  to  be  run  out  of  the  still  by  the  stop-cock  n. 
Although  the  l)oilcr/'  is,  for  the  sake  of  space,  represented  in  the  figure  as  if  placed  beneath 
the  support  of  the  condenser  or  worm  tub,  it  should  in  practice  be  removed  to  a  consider- 
able distance  for  fear  of  the  vapor  of  the  hydrocarbon  reaching  the  stoke-hole  and  causing 
an  explosion.  The  condenser  b  may  be  arranged  in  the  form  of  a  worm  like  c  mficj.  464, 
but  the  precaution  is  scarcely  necessary  if  the  chamber  at  6,  {f(j.  466)  be  made  sufficiently 
capacious.  The  benzole  obtained  in  the  above  apparatus  is,  of  course,  contaminated  with 
toluole ;  if,  however,  the  rectification  be  repeated,  the  water  in  the  chamber  c  c  c  c  not 
being  permitted  to  become  hotter  than  180°  F.,  the  resulting  benzole  will  be  almost  pure. 
One  distillation  is  amply  sufficient  for  the  preparation  of  the  commercial  article. 

A  rectifying  column  somewhat  like  Coffey's  still  may  also  be  employed  for  preparing 
benzole. 

The  less  volatile  naphtha  remaining  in  the  still  is  by  no  means  valueless ;  it  is  adapted 
for  almost  all  the  purposes  for  which  ordinar}'  coal  naphtha  is  applicable.  By  removing 
the  fluid  by  the  tap  A,  and  distilling  it  in  an  ordinary  still,  a  very  good  coal  naphtha  of  a 
density  of  about  0'S70  will  be  obtained. 

The  number  of  processes  and  patents  which  have  been  published  relating  to  coal  naph- 
tha is  immense.  There  is,  as  a  general  rule,  an  extreme  sameness  in  them.  Each  inventor 
uses  the  processes  of  his  predecessors  with  some  slight  alteration  or  modification,  and  patents 
them  as  if  involving  an  important  discovery.  It  is  true  that,  in  some  few  instances,  these 
alterations  are  very  valuable,  but  the  general  feeling  with  which  one  rises  from  the  perusal 
of  patents  connected  with  coal  naphtha  is,  that  there  is  nothing  really  new  in  them.  All 
processes  for  their  purifications  consist,  essentially,  of  treatments  with  strong  oil  of  vitriol 
followed  by  alkalies.  It  is  remarkable  to  observe  the  difference  in  the  ideas  of  inventors 
and  operators  with  regard  to  the  part  played  by  sulphuric  acid  in  the  purification  of  naph- 


NAPHTHA.  793 

thas.  It  is  by  no  means  uncommon  to  hear  the  workmen,  and  even  those  who  have  the 
direction  of  naphtha  works,  attribute  the  dark  color  which  naphthas  acquire  by  contact 
with  oil  of  vitriol,  to  the  latter  '*  precipitating  out  the  tar."  The  fact  i^^,  that  a  carefully  dis- 
tilled naphtha  does  not  contain  any  tar.  The  dark  color  is  chiefly  due  to  the  removal  of 
the  hydrocarbons  homologous  with  olefiant  gas.  All  bodies  belonging  to  this  series  dissolve 
with  a  red  color  in  sulphuric  acid,  and  the  fluid  on  keeping  soon  begins  to  evolve 
sulphurous  acid  and  turn  dark,  sometimes  nearly  black.  If  the  naphtha  has  been  insufficieut- 
ly  rectified,  it  will  contain  naphthaline,  and  this  will  readily  unite  with  the  sulphuric  acid 
to  form  a  conjugate  acid  of  dark  color. 

It  is  extremely  curious  that  naphthas  which  contain  large  quantities  of  naphthaline  will 
often  distil  without  the  latter  crystallizing  out.  It  is  volatilized  in  the  vapor  of  the  naphtha, 
and  therefore  escapes  observation.  But  if  a  little  chlorine  be  poured  into  the  fluid,  or  if  a 
little  chloride  of  lime  be  added,  followed  by  an  acid,  and  the  fluid  be  then  distilled,  the  naph- 
thaline will  come  over  in  the  solid  state,  so  that  it  can  be  removed  by  mechanical  methods. 
It  does  not  appear  to  be  due  to  the  formation  of  Laurent's  chloride  of  naphthaline,  for  the 
product  onl}'  contains  traces  of  chlorine. 

Benzole  has  been  much  used  of  late  to  remove  greasy  and  fatty  matters  from  cotton,  wool, 
silk,  and  mixed  fabrics.  It  is  by  no  means  essential  that  the  benzole  should  be  absolutely 
pure  for  this  purpose.  By  this  it  is  meant  that  the  presence  of  naphthas  boiling  somewhat 
above  177'  does  not  materially  aftect  the  usefulness  of  the  fluid.  If,  however,  the  naphtha 
is  to  be  employed  for  removing  greasy  stains  from  dresses,  gloves,  or  other  articles  to  be 
worn,  the  purer  and  more  volatile  the  hydrocarbon,  the  more  readily  and  completely  the 
odor  will  be  removed  by  evaporation.  Mr.  F.  C.  Calvert  has  patented  the  application  of 
benzole  to  some  purposes  of  this  kind.  He  first  purifies  the  naphtha  by  means  of  sulphuric 
acid  and  caustic  alkalies  in  the  usual  manner,  and  then  rectifies  it  at  a  temperature  not 
exceeding  212'. 

For  this  purpose  the  apparatus  described  in  firt.  466  will  be  found  well  suited.  The  in- 
ventor applies  the  rectified  coal  naphtha,  or  nearly  pure  benzole,  to  the  following  purposes : — 
1st,  for  removing  spots  and  stains  of  grease,  i.  c.  fatty  or  oily  matters,  tar,  paint,  wax,  or 
resin,  from  cotton,  woollen,  silk,  and  other  fabrics,  when,  in  consequence  of  its  volatility,  no 
mark  or  permanent  odor  remains ;  2d,  for  removing  fatty  or  oily  matters  from  hair,  furs, 
feathers,  and  wools,  and  for  cleaning  gloves  and  other  articles  made  of  leather,  hair,  fur, 
and  wool;  3d,  for  removing  the  fatty  matters  which  exist  naturally  in  wool;  4th,  for 
removing,  from  wool,  tar,  paint,  oil,  grease,  and  similar  substances  used  by  farmers  for 
marking,  salving,  and  smearing  their  sheep ;  5th,  for  cleansing  or  removing  the  oily  or  fatty 
matters  which  are  contained  in  cotton  waste  that  has  been  used  for  cleansing  or  wiping 
machinery,  or  other  articles  to  which  oil  or  grease  has  been  applied.  In  order  to  remove 
the  above  matters  by  means  of  coal  naphtha,  the  articles,  if  small,  are  merely  rubbed  with  it. 
On  the  large  scale  the  matters  to  be  operated  on  are  placed  in  suitable  vessels,  and  the  naph- 
tha is  run  in.  After  contact  for  some  hours  the  fluid  is  run  off,  and  the  fabrics  are  passed 
through  squeezers  and  submitted  to  strong  pressure  to  remove  the  greater  portion  of  the 
benzole  or  naphtha.  The  naphth;is  which  run  out  are  distilled  off,  so  that  the  greasy  matters 
may  be  preserved  and  used  for  lubricating  machinery  or  other  purposes. 

Furniture  paste  may  also  be  made  from  light  coal  naphtha  or  benzole  by  the  following 
process: — One  part  of  wax  and  one  of  resin  is  to  be  dissolved  in  two  parts  of  the  liydrocar- 
bon,  with  the  aid  of  heat.  When  entirely  dissolved  the  whole  is  allowed  to  cool,  and  is  then 
fit  for  use. 

It  is  a  vexatious  circumstance  that  no  important  practical  use  has  been  found  for  naph- 
thaline. It  is  true  that  it  is  used  for  the  preparation  of  lampblack,  but  the  (piantity  employed 
for  that  purpose  is  but  small.  The  quantity  annually  produced  by  the  various  gas-works  is 
enormous.  Its  odor  and  volatility  prevent  its  Ijeing  applied  to  lubricating  purposes.  It 
often  happens  that  much  valuable  time  is  lost  by  unscientific  operators  in  endeavoring  to 
remove  the  smell  from  such  substances  as  naphthaline :  they  forget  that  the  odor  of  a  body 
of  this  class  is  a  part  of  itself,  and  cannot  be  removed  without  its  destruction.  It  is  possible 
that  the  compounds  of  naphthaline  may  one  day  be  applied  to  useful  purposes.  By  treating 
naphthaline  with  excess  of  chlorine,  and  removing  fluid  substances  with  ether,  a  crystalline 
paste  is  obtained.  This  paste,  dissolved  in  boiling  benzole  and  allowed  to  repose,  deposits 
beautiful  rhombohedral  crystals,  often  of  large  size.  They  have  exactly  the  form  of  Iceland 
spar,  and,  like  that  substance,  possess  the  power  of  double  refraction.  When  nitronaphtha- 
line  is  treated  with  acetic  acid  and  iron  filings  in  the  same  manner  as  that  employed  by  JI. 
Bechamp  for  the  production  of  aniline,  a  base  is  obtained  of  the  formula  C-"'H''X ;  it  is  called 
naphthalamine.  It  is,  therefore,  isomeric  with  cryptidine,  but  has  no  other  point  of  resem- 
blance. 

The  relation  which  appears  to  exist  between  naphthaline  and  alizarine  is  also  very 
interesting,  and  suggestive  of  the  idea  that  the  former  substance  will  not  always  be  regarded 
as  useless. 

It  is  said  that  naphthaline  has  been  employed  with  advantage  in  the  treatment  of 


794  NAPHTHA. 

psoriasis.  M.  Emery  states  that  it  succeeded  in  twelve  out  of  fourteen  cases.  In  the  two 
where  it  failed,  the  one  patient  was  a  woman  thirty  years  of  age,  who  had  been  afflicted  for 
eight  years  with  psoriasis  gyrata ;  the  other  patient  was  a  young  man  who  had  suflered 
for  several  years  with  lepra  vulgaris.  In  the  latter  case,  two  months'  treatment  having  effect- 
ed no  good,  pitch  ointment  v,-as  substituted,  which  effected  a  cure  in  two  months.  The  naph- 
thaline was  employed  in  the  form  of  ointment  in  the  strength  of  3  ss.  to  3  i.  of  lard.  The 
application  is  sometimes,  however,  attended  with  severe  inflammatiou  of  the  skin,  which  must 
be  relieved  with  poultices.     {L'' Experience,  Oct.  6,  1842.) 

The  dead  oils,  as  the  less  volatile  parts  of  coal  tar  are  called,  contain  several  substances, 
the  nature  of  which  is  very  imperfectly  known.  Among  them  maybe  mentioned  pyrene  and 
chrysfene.  The  former  has  only  been  examined  by  Laurent,  who  gives  the  formula  C^"H" 
for  it.  They  are  found  in  the  very  last  portions  that  pass  in  the  distillation  of  coal  tar. 
They  are  also  said  to  be  produced  during  the  distillation  of  fatty  or  resinous  substances. 
The  portions  which  distil  last  are  in  the  form  of  a  reddish  or  yellowish  paste,  which  rapidly 
darkens  in  color  on  exposure  to  light.  Ether  separates  it  into  two  portions,  one  soluble, 
containing  the  pyrene,  the  other  insoluble  containing  the  chrysene.  The  pyrene  may  be 
obtained  by  exposing  the  etherial  solution  to  a  very  slow  temperature,  which  will  cause  it  to 
crystallize  out.     The  composition  of  pyrene  is,  according  to  Laurent, 

Experiment.  Cnlculation. 

Carbon         ...         -         93-18    -         -         -         C'°     93-7 
Hydrogen    -        .        -        -  611    -        -        -        H"      6-3 

99-29  100-0 

The  portion  insoluble  in  ether  consists  of  chrysene  in  a  tolerably  pure  state.     I  have 
found  that  it  crystallizes  on  cooling  from  a  solution  in  Boghead  naphtha,  in  magnificent  yel- 
low plates,  with  a  superb  lustre  resembling  crystallized  iodide  of  lead.     The  following  are 
the  results  of  its  analysis.     My  combustion  was  made  upon  chrysfene  crystallized  as  above. 
Laurent.  C.  G.  "W.  Calculation. 

Carbon     -         -     94-83     94-25  94-63  94-74     C"  72 

Hydrogen         -       5-44       5-30  5-37  5-26     H*     4 


100-27    99-55  100-00  100-00  76 

The  formula  given  above  merely  expresses  the  ratio  of  the  elements ;  no  compound  of 
chrvsene  has  yet  been  formed  which  will  enable  it*  atomic  weight  to  be  determined  with 
certainty.     Laurent's  analyses  were  calculated  with  old  atomic  weight  of  carbon. 

The  heavier  coal  oils,  when  exposed  to  the  action  of  a  powerful  freezing  mixture,  often 
deposit  a  mass  of  crystals  only  partly  soluble  in  alcohol.  The  soluble  portion  consists  of 
naphthaline;  the  other  portion,  which  dissolves  with  difficulty,  is  a  curious  substance,  the 
nature  of  which  is  at  present  not  very  well  known ;  it  has  been  called  anthracene,  or  para- 
naphthaline.  It  appears,  from  the  analyses  which  have  as  yet  been  made,  to  be  isomeric 
•with  naphthaline.  It  fuses  at  356°,  and  boils  at  about  580^  The  density  of  its  vapor,  deter- 
mined at  848°,  was  6-741°,  agreeing  very  well  with  the  formula  C'"!!'^  which  requires  6-643. 
This  formula  is  one  and  a  half  times  naphthaline,  thus :  C""!!"  +  C'"!!*  :rr  C=''H". 

Metanaphthaline  is  a  peculiar  substance  which  appears  to  be  closely  related  to  the  above 
products.  It  is  formed  during  the  manufacture  of  resin  gas.  It  is  a  fatty  substance  fusing  at 
158°,  and  distilling  atabout  617° ;  it  is  at  present  but  little  known.  A  substance  which  seems 
to  be  metanaphthaline  has  recently  been  imported  in  considerable  quantity  as  a  lubricating 
material.     It  is  tinged  of  a  yellow  color,  probably  from  the  presence  of  traces  of  chrysene. 

NAPHTHA,  Native.  In  a  great  number  of  places  in  various  parts  of  the  world,  a 
more  or  less  fluid  inflammable  matter  exudes.  It  is  known  as  Persian  naphtha.  Petroleum, 
Rock  oil,  Rangoon  tar,  Burmese  naphtha,  &c.  These  naphthas  have  been  examined  by 
many  chemists,  but  the  experiments  have  been  exceedingly  defective,  and  even  the  analyses 
most  incorrect,  for  in  most  cases  where  a  loss  of  carbon  or  hydrogen  has  been  experienced, 
it  has  been  put  down  as  oxygen.  The  oil  procured  from  the  above  source,  when  rectified 
and  well  dried,  contains  no  oxygen.  The  constitution  of  all  of  them  is  probably  nearly  the 
same,  the  odor  and  physical  characters  closely  agreeing  in  specimens  obtained  from  widely 
different  sources.  A  thorough  investigation  of  the  most  plentiful  and  well  marked  of  all  of 
these  naphthas  (namely  that  Irom  Rangoon)  has  been  undertaken  by  MM.  Warren  De  la  Kue 
and  Hugo  Miiller,  who  have  been  engaged  upon  it  for  some  years.  They  find  the  fluid  to 
consist  of  two  principal  series  of  hydrocarbons,  namely  the  benzole  class  and  another  unacted 
upon  by  acids,  and  apparently  consisting  of  the  radicals  of  the  alcohols.  In  addition  to  the 
fluid  hydrocarbons,  Burmese  naphtha  contains  a  considerable  quantity  of  paraffine. 

Burmese  naphtha  or  Rangoon  tar  is  obtained  by  sinking  wells  about  60  feet  deep  in  the 
soil ;  the  fluid  gradually  oozes  in  from  the  soil,  and  is  removed  as  soon  as  the  quantity  accumu- 
lated is  sufficient.  The  crude  substance  is  soft,  about  the  consistence  of  goose  grease,  with  a 
greeni.sh  brown  color,  and  a  peculiar  but  by  no  means  disagreeable  odor.  It  contains  only 
4  per  cent,  of  fixed  matter.     In  the  distillations,  MM.  De  la  Rue  and  Miiller  employed  super- 


NAPHTHA. 


Y95 


heated  steam  for  the  higher,  and  ordinary  steam  for  the  lower  temperatures.  At  a  temperature 
of  212\  eleven  per  cent,  of  fluid  hydrocarbons  distil  over;  they  are  entirely  free  from 
paraffine.  Between  230"  and  290°  F.,  ten  per  cent,  more  fluid  distils,  containing,  how- 
ever, a  very  small  quantity  of  paralfine.  Between  the  last-named  temperature  and  320'  F. 
the  distillate  is  very  small  in  quantity,  but  from  that  to  the  fusing  point  of  lead,  20  per  cent, 
more  id  obtained.  The  latter,  although  containing  an  appreciable  amount  of  paraffine,  re- 
mains fluid  at  32°  F.  At  this  epoch  of  the  distillation,  the  products  begin  to  solidify  on 
cooling,  and  31  per  cent,  of  substance  is  obtained  of  sufficient  consistency  to  be  submitted 
to  pressure.  On  raising  the  heat  considerably,  21  per  cent,  of  fluids  and  paraffine  distil 
over.  In  the  last  stage  of  the  operation,  3  per  cent,  of  pitch-like  matters  are  obtained.  The 
residue  in  the  still,  consisting  of  coke  containing  a  little  earthy  matter,  amounts  to  4  percent. 
We  thus  have  as  the  products  in  this  very  carefully  conducted  and  instructive  distillation, 


Below  212°  - 
230°  to  293°  - 
293"  to  320°  - 
320°  to  fusing  point  of  lead 


Free  from  paraffine 
A  little  paraffine 


Containing  paraffine,   but  still 
fluid  at  320° 

At  about  the  fusing  point  of  lead,    Sufficiently  solid  to  be  submit- 
ted to  pressure 
Beyond  fusing  point  of  lead     -         -    Quantity  of  paraffine  diminishes  - 

Last  distilled Pitchy  matters  -         -         -         ■ 

Residue  in  still        ....    Coke  containing  a  little  earthy 

impurity        .         .         .         . 


110 
10-0 


200 

Sl-0 

210 

3  0 

40 

100-0 


All  the  above  distillates  are  lighter  than  water.  Almost  all  the  paraffine  may  be  extracted 
from  the  distillates  by  exposing  them  to  a  freezing  mixture.  In  this  manner,  uoless  than 
between  10  and  11  per  cent,  of  this  valuable  solid  hydrocarbon  maybe  obtained  from 
Burmese  naphtha.  We  may  before  long  expect  a  full  account  of  the  substances  contained 
in  Rangoon  tar. — C.  G.  W. 

NAPHTHA,  SiiALK.  The  true  constitution  of  .shale  naphtha,  or,  as  it  is  sometimes 
called  in  commerce  "shale  oil,"  has  not  yet  been  satisfactorily  ascertained.  In  fact,  to  do 
so  would  involve  a  very  laborious  research,  or  rather  series  of  researches,  for  the  various 
shales  or  schists  differ  much  in  the  quantities  and  qualities  of  the  naphtha  yielded  by  them. 
The  bituminous  shale  of  Dorsetshire  contains  much  nitrogen  and  sulphur,  arising  to  a  great 
extent  from  presence  of  a  large  quantity  of  semi-fossilized  animal  remains.  The  crude  naph- 
tha, consequently,  is  intolerably  fuetid.  By  repeated  treatments  with  concentrated  sulphu- 
ric acid  and  caustic  soda  it  may,  however,  be  rendered  very  sweet.  It  then  contains  pretty 
nearly  the  same  constituents  as  Boghead  naphtha,  i.  c.  benzole  and  its  homologues,  various 
hydrocarbons  of  the  olefiant  gas  series,  and  small  quantities  of  the  alcohol  radicals  or  iso- 
meric hydrocarbons.  There  are  also  present,  previous  to  purification,  carbolic  acid  and 
numerous  alkaloids ;  but,  strange  to  say,  in  the  samples  I  examined  there  was  no  trace  of 
aniline  to  be  found.  There  is  little  doubt  that  shales  of  this  kind  might  be  most  profitably 
worked  by  one  or  other  of  the  recently  patented  processes  for  the  preparation  of  photogen 
and  lubricating  oil. 

French  shale  oils  have  been  examined  by  Laurent  and  Sainte  Evre,  but  the  results  are 
not  of  any  very  great  value,  because  care  was  not  taken  to  separate  the  various  series  of 
hydrocarbons  from  each  other.  It  is  true  that  Laurent  fractionally  distilled  his  oil,  and 
Sainte  Evre  in  addition  treated  his  hycrocarbons  with  sulphuric  acid,  anhydrous  phosphoric 
acid,  and  fused  potash.  These  operations  would  remove  basic  and  acid  bodies,  and  much, 
if  not  all,  of  the  homologues  of  olefiant  gas,  but  the  residue  would  contain  indefinite  mixtures 
of  the  benzole  and  radical  series. 

Laurent's  analyses  have  been  quoted  by  Gerhardt  to  show  that  the  hydrocarbons  approach 
in  composition  the  formula  n(C"ir'').     They  are  as  follows: — 

SO"  to  05°  C  120°  to  1'21°  109°  Theory  11(0=112) 

Carbon         -         -     86-0        85-7     -         8(i-2  85-6  -  85-7 

Hydrogen    -         -     14-3        141     -         13G  14-5  -  14-3 

100-0 
The  above  analyses  are  calculated  according  to  the  old  atomic  weight  of  carbon. 
M.  Sainte  Evre,  by  determining  the  vapor  densities  of  the  fractions,  arrived  at  the  fol- 
lowing Ibrmula  for  the  hydrocarbons  examined  by  him : — 

Boiling  points  Cent.  Formula. 

275"    to  280° C^-^H^* 

255°   to  2G0° C"H" 

215°    to  220° C^IP' 

132°    to  135° C"H" 


796 


NATUEE-PPJNTIN. 


These  results  are  worth  very  little  except  as  showing  where  an  excellent  field  exists  for 
invc.-^tigation. 

Lament,  by  treating  with  boiling  concentrated  nitric  acid  that  part  of  shale  oil  which 
boiled  between  80'  and  1 50 '  Cent.,  obtained  an  acid  which  he  called  ampelic ;  it  is  apparently 
metameric  with  salicylic  acid.  Tiie  same,  or  more  probably  a  homologous  substance,  is 
procured  by  treating  in  the  same  manner  the  oil  boiling  between  130^  and  160^.  Picric,  or, 
as  it  is  sometimes  called,  carbazotic  acid,  is  also  formed  at  the  same  time. 

Ampelic  acid  is  a  substance  about  wliich  chemists  have  felt  much  curiosity  ever  since 
its  discovery.  It  is  much  to  be  desired  that  a  new  investigation  should  be  made  upon  it. 
The  following  are  a  few  of  its  properties: — It  is  white,  inodorous,  almost  insoluble  in  cold 
water,  and  only  slightly  soluble  even  when  boiling ;  the  solution  reddens  litmus.  It  is  easily 
dissolved  by  alcohol  or  ether ;  from  solution  in  those  menstrua  it  is  deposited  under  the  form 
of  a  crystalline  powder.  It  fuses  somewhere  about  200"  Cent.,  and  distils  without  alteration. 
This  last  property  is  a  valuable  one,  as  it  will  enable  its  vapor  density,  and  consequently  its 
atomic  weight,  to  be  easily  determined  with  precision.  From  its  solution  in  sulphuric  acid 
it  is  precipitated  unaltered  by  water.  Gerhardt  gives  the  following  as  some  of  the  reactions 
of  this  interesting  body.  The  solution  of  its  ammonia  salt  precipitates  chloride  of  calcium 
white,  the  precipitate  is  soluble  in  hot  v.ater,  and  crystallizes  on  cooling.  It  is  not  precipi- 
tated by  solutions  of  the  chlorides  of  barium,  strontium,  manganese,  or  mercury.  Acetate 
of  nickel  gives  a  greenish  precipitate,  acetate  of  copper  greenish  blue.  Acetate  and  nitrate 
of  lead  gives  white  precipitates. 

The  above  experiments  were  made  by  Laurent  in  1S37,  and,  as  it  is  very  probalile  that  he 
never  obtained  a  perfectly  pure  substance,  it  is  almost  certain  that  valuable  and  novel  results 
would  be  obtained  on  carefully  repeating  the  entire  investigation.  At  the  same  time,  as 
benzoic  acid  is  CH^O^'and  ampelic  acid  according  to  its  discoverer  is  C"H"0^,  it  is  more 
than  likely  to  be  a  product  of  oxidation  of  one  of  the  homologues  of  benzole. 

Intimately  connected  with  the  oils  of  shale  are  the  fluids  yielded  by  the  distillation  of 
the  numerous  bitumens  and  asphalts  found  in  various  parts  of  the  world.  Undoubtedly 
these  deposits  will  one  day  become  of  important  use  in  the  arts. 

The  bitumen  of  Trinidad  yields  on  distillation  an  intensely  foetid  oil,  and  also  a  very 
large  quantity  of  water.  It  also  appears  to  give  a  considerable  quantity  of  alkaloids  and 
ammonia.  It  will,  perhaps,  scarcely  be  a  profitable  speculation  at  present  to  bring  this  bit- 
umen so  far  for  the  purpose  of  distillation,  but  doubtless  there  are  many  ports  into  which 
it  could  be  carried  at  a  reasonable  price.  It  is  said  that  some  has  already  found  its  way  into 
America,  for  the  purpose  of  having  photogen  prepared  from  it. 

France  is  particularly  rich  in  deposits  of  bitumen,  especially  in  the  volcanic  districts  of 
Auvergne.  Switzerland,  Italy,  Germany,  Russia,  Poland,  in  fact  almost  every  part  of 
Europe,  contains  bitumen  of  various  degrees  of  consistency  and  value.  Even  in  our  own 
country  there  are  deposits  at  Alfreton  and  other  places.  The  Alfreton  bitumen  is  not  un- 
like that  of  Rangoon. 

Bitumens  have  been  examined  by  various  chemists,  more  especially  by  Bousingault  and 
Yoelckel.  Their  results,  however,  require  to  be  repeated  with  great  care,  as  hitherto 
sufficient  attention  has  not  been  paid  to  the  purification  by  chemical  means  of  the  various 
hydrocarbons.  Fractional  distillation,  although  absolutely  necessary,  in  order  to  enable 
bodies  to  be  obtained  of  different  but  specific  boiling  points,  does  not  do  away  with  the 
necessity  for  elaborate  purifications  by  means  of  bromine,  nitric,  and  sulphuric  acids,  &c. 

There  is  little  doubt  that  a  rigorous  examination  of  the  oils  procurable  by  distillation  of 
the  various  European  and  other  bitumens,  would  be  rewarded,  not  only  by  scientific  results 
of  great  interest,  but  also  by  discoveries  of  immense  commercial  importance.  It  must  not 
be  forgotten,  in  connection  with  the  money  value  of  such  researches,  that  the  bitumens  yield 
a  vei  y  high  percentage  of  distillate,  much  greater  than  any  of  the*  shales  or  imperfectly 
fossilized  coals  which  are  wrought  on  the  large  scale  for  the  preparation  of  illuminating  or 
lubricating  oils. — C.  G.  W. 

NATURE-PRIXTIXG.  {Xntnrsdhstdrncl;  Germ.)  The  following  description  of  this 
very  beautiful  process  is  an  abstract  of  a  lecture  delivered  by  Mr.  Heury  Bradbmy  at  the 
Royal  Institution: — 

Nature-printing  is  the  name  given  to  a  technical  process  for  obtaining  printed  repro- 
ductions of  plants  and  other  objects  upon  paper,  in  a  manner  so  truthful  that  only  a  close 
inspection  reveals  the  fact  of  their  being  cojiics  ;  and  so  distinctly  sensililc  to  even  touch 
are  the  impres-sions,  that  it  is  ditticult  to  persuade  those  unacquainted  with  the  manipulation 
that  they  are  an  emanation  of  the  printing-press. 

The  distinguishing  feature  of  the  process  consists,  firstly,  in  impressing  natural  objects — 
such  as  plants,  mosses,  seaweeds  and  feathers — into  plates  of  metal,  causing  as  it  were  the 
objects  to  engrave  themselves  by  pressure ;  secondly,  in  being  aide  to  take  such  casts  or 
copies  of  the  impressed  plates  as  can   be  printed  from  at  the  ordinary  cop])crplate-press. 

This  secures,  in  the  case  of  a  j)Iant,  on  the  one  hand,  a  perfect  representation  of  its 
characteristic  outline,  of  some  of  the  other  external  marks  by  which  it  is  known,  and  even 


NATOEE-PEINTING.  797 

in  some  measure  of  its  structure,  as  in  the  venation  of  ferns,  and  the  ribs  of  the  leaves  of 
flowering  plants ;  and  on  the  other,  affords  the  means  of  multiplying  copies  in  a  quick  and 
easy  manner,  at  a  trifling  expense  compared  with  the  result — and  to  an  unlimited  extent. 

The  great  defect  of  all  pictorial  representations  of  botanical  figures  has  consisted  in  the 
inability  of  art  to  represent  faithfully  those  minute  peculiarities  by  which  natural  objects 
are  often  best  distinguished.  Nature-printing  has  therefore  come  to  the  aid  of  this  branch 
of  science  in  particular,  whilst  its  future  development  promises  facilities  for  copying  other 
objects  of  nature,  tlie  reproduction  of  which  is  not  within  the  province  of  the  human  hand 
to  execute  ;  and  even  if  it  were  possible,  it  would  involve  an  amount  of  labor  scarcely  com- 
mensurate with  the  result. 

Possessing  the  advantages  of  rapid  and  economic  production,  the  means  of  unlimited 
multiplication,  and,  above  all,  unsurpassable  resemblance  to  the  original.  Nature-printing  is 
calculated  to  assist  much  in  facilitating  not  only  the  firsi-f<ight  recognition  of  many  objects 
in  natural  history,  but  in  supplying  the  detailed  evidences  of  identification — which  must 
prove  of  essential  value  to  botanical  science  in  particular. 

Experiments  to  print  direct  from  nature  were  made  as  far  back  as  about  two  hundred 
and  fifty  years ;  it  is  certain,  therefore,  that  the  present  success  of  the  art  is  mainly  attribut- 
able to  the  general  advance  of  science,  and  the  perfection  to  which  it  has  been  brought  in 
particular  instances. 

On  account  of  the  great  expense  attending  the  production  of  woodcuts  of  plants  in  early 
times,  many  naturalists  suggested  the  possibility  of  making  direct  use  of  Nature  herself  as  a 
copyist.  In  the  Book  of  Art,  of  Alexis  Pedemontanus  (printed  in  the  year  1572),  and 
translated  into  German  by  Wecker,  may  be  found  the  Jirst  recorded  hint  as  to  taking 
impressions  of  plants. 

At  a  later  period — in  the  Journal  des  Voyages,  by  M.  de  Moncoys,  in  1650,  it  is 
mantioned  that  one  Welkenstein,  a  Dane,  gave  instruction  in  making  impressions  of  plants. 
The  process  adopted  to  produce  such  results  at  this  period  consisted  in  lying  out  flat 
and  drying  the  plants.  By  holding  them  over  the  smoke  of  a  candle,  or  an  oil  lamp,  they 
became  blackened  in  an  equal  manner  all  over ;  and  by  being  placed  between  two  soft 
leaves  of  paper,  and  being  rubbed  down  with  a  smoothing  bone,  the  soot  was  imparted  to 
the  paper,  and  the  impression  of  the  veins  and  fibres  was  so  transferred.  But  though  the 
plants  were  dried  in  every  case,  it  was  l)y  no  means  absolutely  necessary  ;  as  the  author  has 
proved  by  the  simple  experiment  of  applying  lampblack  or  printer's  ink  to  a  fresh  leaf, 
and  producing  a  successful  impression. 

Linnaeus,  in  his  Philosophia  Botanica,  relates  that  in  America,  in  1707,  impressions  of 
pi  ints  were  made  by  Hessel ;  and  later  (172S-1 757),  Professor  Kniphof,  at  Erfurt  (who  refers 
to  the  experiments  of  Hessel),  in  conjunction  with  the  bookseller  Fiaike,  established  a  print- 
ing-office for  the  purpose.  He  produced  a  work  entitled  Herbarium  Vivuin.  The  range 
and  extent  of  his  work,  twelve  folio  volumes,  containing  1,200  plates,  corroborates  the 
curious  fact  of  a  printing-office  being  required.  These  impressions  were  obtained  by  the 
substitution  of  printer's  ink  for  lampblack,  and  flat  pressure  for  the  smoothing-bone  ;  but 
a  new  feature  at  this  time  was  introduced — that  of  coloring  the  impressions  by  hand  accord- 
ing to  nature — a  proceeding,  which  though  certainly  contributing  to  the  beauty  and  fidelity 
of  the  effect,  yet  had  the  disadvantage  of  frequently  rendering  indistinct,  and  even  of  some- 
times totally  obliterating,  the  tender  structure  and  finer  veins  and  fiVires.  Many  persons  at 
the  time  objected  to  the  indistinctness  of  such  representations,  and  the  absence  of  parts  of 
the  fructification  ;  but  it  was  the  decided  opinion  of  Linnajus,  that  to  obtain  a  representation 
of  the  difference  of  species  was  sufficient. 

In  1748,  Seligraann,  an  engraver  at  Nuremberg,  published  in  folio  plates  figures  of 
several  leaves  he  had  reduced  to  skeletons.  As  he  tiiought  it  impossible  to  make  drawings 
sufficiently  correct,  he  took  impressions  from  the  loaves  in  red  ink,  but  no  mention  is  made 
of  the  means  he  adopted.  Of  the  greater  part  he  gave  two  figures,  one  of  the  upper  and 
another  of  the  lower  side. 

In  the  year  17G3  the  process  is  again  referred  to  in  the  Gazette  Salutairc,  in  a  short 
article  upon  a  Recette  pour  copier  toutes  sortcs  de  plantcs  snr  papier. 

About  twenty-five  or  thirty  years  later,  Iloppe  edited  his  Edypa  Plantarum  Ratis- 
bonen^ium,  and  also  his  Ecti/pa  Plantarum  Sclcctarum,  the  illustrations  in  which  were 
produced  in  a  manner  similar  to  that  employed  by  Kniphof.  These  impressions  were  found 
also  to  be  durable,  but  still  were  defective. 

In  the  year  1809  mention  is  made  in  Pritzell's  "  Thesaurus"  of  a  New  Method  of  taking 
Natural  Impressions  of  Plants ;  and  lastly,  in  reference  to  the  early  history  of  the  subject, 
the  attention  of  scientific  men  was  called  to  an  article,  in  a  work  published  by  Grazer,  in 
1814,  on  a  New  Impression  of  Plants. 

Twenty  years  afterwards,  the  subject  had  undergone  remaikable  change,  not  only  in  the 
results  produced,  but  also  in  the  niu(le  of  oixnation  to  be  pursued,  wliich  consisted  in  lixing 
an  impression  of  the  prepared  plant  in  a  plate  of  metal  by  pressure.  It  also  appears,  on 
the  autliority  of  Professor   Thiele,  that  Peter   Kyhl,  a  Danish  goldsmith   and   engraver, 


798  NATURE-PRINTING. 

established  at  Copenhagen,  applied  himself  for  a  length  of  time  to  the  ornamentation  of 
articles  in  silver  ware,  and  the  means  he  adopted  were,  taking  copies  of  flat  objects  of  nature 
and  art  in  plates  of  metal  by  means  of  two  steel  rollers.  Here  may  be  marked  the  first  real 
steps  of  the  process,  from  a  simple  contrivance  to  an  art.  The  subsequent  development 
which  science  has  given  to  these  means,  and  the  amplifications  which  experience  has  added, 
have  realized  what  can  now  be  produced  ;  but  it  should  not  be  assumed  that  adaptation  and 
amplification  are  invention. 

Various  productions  in  silver,  of  KyhPs  process,  were  exposed  in  the  Exhibition  of 
Industry  held  at  Charlottenburg,  in  May,  1833.  In  a  manuscript,  written  by  this  Danish 
goldsmith,  entitled  21ie  Descri/dion  {with  forty-six  plates)  of  the  Method  to  copy  Flat  Ob- 
jects of  Nature  and  Art,  dated  1st  May,  1833,  is  suggested  tl.e  idea  of  ajiplying  this 
invention  to  the  advancement  of  science  in  general.  The  plates  accompanying  this  de- 
scription represented  printed  copies  of  leaves,  of  linen  and  woven  stuffs,  of  laces,  of  feathers 
of  birds,  scales  of  fishes,  and  even  of  serpent-skins. 

It  would  appear  that  Peter  Kyhl  was  no  novice  at  the  process.  lie  distinctly  points  out 
what  he  conceives  to  be  its  value,  by  the  subjects  that  he  tried  to  copy,  and  he  enters  into 
detail  as  to  the  precautions  to  be  observed  in  the  operation  of  impressing  metal  plates  so  as  to 
insure  successful  impressions.  His  manuscript  explains  that  he  had  experimented  with 
plates  of  copper,  zinc,  tin,  and  lead.  Still  tliere  existed  obstacles  which  prevented  him 
from  making  any  application  of  his  invention.  In  the  case  of  zinc,  tin,  and  copper  plates, 
the  plant,  from  the  extreme  hardness  of  the  metals,  was  too  much  distorted  and  crushed ; 
while  in  lead,  tliough  the  impression  was  as  perfect  as  could  be,  there  were  no  means  of 
printing  many  copies ;  as  it  was  not  possible,  after  the  application  of  printer's  ink,  to  retain 
the  polished  surface  that  had  been  imparted  to  the  leaden  plate,  or  to  cleanse  it  so  thorough- 
ly as  to  allow  the  printer  to  take  impressions  free  from  dirty  stains.  This  was  a  serious  obsta- 
cle, which  was  not  compensated  for  even  by  the  peculiarly  rich  surface  of  the  parts  that  were 
impressed,  attributable  to  the  lead  being  more  granular  than  copper,  the  effect  of  which  is  so 
favorable  to  adding  density  or  body  of  color,  without  obliterating  the  veins  and  fibres.  Peter 
Kyhl  died  in  the  same  year  that  he  made  known  his  invention.  At  his  death,  his  manuscripts 
and  drawings  were  deposited  in  the  archives  of  the  Imperial  Academy  of  Copenhagen. 

To  proceed  to  more  modern  efforts.  Dr.  Branson,  of  ^Sheffield,  in  1847,  commenced  a 
series  of  experiments,  an  interesting  paper  upon  which  was  read  before  the  Society  of  Arts 
in  1851  ;  and  therein,  for  the  first  time,  was  suggested  the  application  of  that  second  and 
most  important  element  in  Nature-printing,  which  is  now  its  essential  feature — the  Electrotype. 

It  then  occurred  to  Dr.  Branson  that  an  Electrotype  copy  would  obviate  the  difficulty. 

lie  afterwards  .stated  that  he  abandoned  the  process  of  Electrotyping  in  consequence  of 
liis  finding  it  tediou.s,  troublesome,  and  costly  to  produce  large  plates.  Having  occasion, 
however,  to  get  an  article  cast  in  brass,  he  was  astonished  at  the  .beautiful  manner  in  which 
the  form  of  the  model  was  reproduced  in  the  metal.  He  determined,  therefore,  to  have  a 
cast  taken  in  brass  from  a  gutta-percha  mould  of  ferns,  and  was  much  gratified  to  see  the 
impression  rendered  almost  as  minutely  as  by  the  Electrotype  process  ;  the  mode  of  opera- 
tion is  to  place  a  frond  of  fern,  algae,  or  similar  flat  vegetable  foi-m,  on  a  thick  piece  of 
glass  or  polished  marble  ;  by  softening  a  piece  of  gutta-percha  of  proper  size,  and  placing  it 
on  the  leaf  and  pressing  it  carefully  down,  it  will  rc/;eive  a  .«harp  and  accurate  impression 
from  the  plant.  The  gutta-percha,  allowed  to  harden  by  cooling,  is  then  handed  to  a  brass- 
caster,  who  reproduces  it  in  metal  from  its  moulding-base. 

In  18.51,  Professor  Leydolt,  of  the  Imperial  Polytechnic  Institute  at  A'ienna,  availing 
himself  of  the  resources  of  the  Imperial  Printing-Ofiice,  carried  into  execution  a  new  method 
he  had  conceived  of  representing  agates  and  other  quartzose  minerals  in  a  manner  true  to 
nature.  Professor  Leydolt  had  occupied  himself  for  a  considerable  period  in  examining  the 
origin  and  composition  of  these  interesting  olijects  in  geology.  In  the  course  of  his  experi- 
ments and  investigations  he  had  occasion  to  expose  tliem  to  the  action  of  fluoric  acid,  when 
he  found  in  the  case  of  an  agate,  that  many  of  the  concentric  rings  were  totally  unchanged, 
while  others,  to  a  great  extent  decomposed  by  the  acid,  appeared  as  hollows  between  the 
u:ialtered  bands.  It  then  occurred  to  Professor  Leydolt  that  the  surfaces  of  bodies  thus 
corroded  might  be  printed  from,  and  copies  multiplied  with  the  greatest  facility. 

The  simplest  mode  for  ol)taining  printed  copies  is  to  take  an  impression  direct  from  the 
stone  itself.  Tiie  surface,  after  having  Ijccn  treated  with  fluoric  acid,  is  wa.-^hed  with  dilute 
hydrochloric  acid  and  dried  ;  then  carefully  blackened  with  printer's  ink.  By  placing  a  leaf 
of  paper  upon  it,  and  by  pressing  it  down  upon  every  portion  of  the  etched  or  corroded 
surface  with  a  burnisher,  an  impression  is  obtained,  representing  the  crystallized  rhomboidal 
quartz,  black,  and  the  weaker  parts  that  have  been  decomposed  by  the  action  of  the  acid, 
V'hite.  It  requires  but  a  small  quantity  of  ink,  and  particular  care  must  be  exercised  in  the 
rubbing  down  of  the  impression.  This  mode  is  good  as  far  as  it  goes — but  it  is  slow  and 
uncertain — and  incurs  a  certain  amount  of  risk,  owing  to  the  brittle  nature  of  the  object ; 
and  the  effect  produced  is  not  altogether  correct,  since  it  represents  those  portions  black 
that  should  be  white,  and  those  white  that  should  be  black. 


NICOTINE.  799 

The  stone  not  being  sufficiently  strong  to  be  subjected  to  the  action  of  a  printing-press, 
an  exact  fac-xi/nile  cast,  therefore,  of  it  must  be  obtained,  and  in  such  a  form  as  can  be 
printed  fiotn.  To  effect  this,  the  surfiicc  of  any  such  stone  (previously  treated  witli  fluoric 
acid)  must  be  extended  by  embedding  it  in  any  plastic  composition  tliat  will  yield  a  flat 
and  polished  surface,  so  that  the  composition  surrounding  tlie  corroded  stone  will  be  level 
with  its  surface  ;  all  that  is  necessary  now  is  to  prepare  the  whole  surface  for  the  electrotype 
apparatus,  by  wliich  a  peri'ect  facsimile  is  produced,  representing  the  agate  impressed,  as  it 
were,  into  a  polisheil  plate  of  copper.  This  forms  tjie  printing-plate.  The  ink  in  this  case, 
as  opposed  to  tiio  mode  before  referred  to,  is  not  applied  upon  the  surface,  but  in  the  de- 
p;-essions  caused  by  the  action  of  the  acid  on  the  weaker  parts ;  the  paper  is  forced  into 
these  depressions  in  the  operation  of  printing,  which  results  in  producing  an  impression  in 
relief. 

Mr.  R.  F.  Sturges,  of  Birmingham,  states  that  in  August,  1851,  he  was  engaged  in 
making  certain  experiments  with  steel  rollers  and  metal  plates  for  ornamenting  metallic 
surfices,  for  wliich  he  obtained  a  patent  sealed  in  January,  1852.  He  produced  plates  in 
lead,  tin,  brass,  and  steel  from  various  fai)rics,  such  as  wire  lace,  thread  lace,  perforated 
puper,  and  even  from  steel  engravings,  particularly  a  medallion  of  the  Queen,  from  which 
impressions  were  printed,  and  which  were  distributed  among  his  friends — but  that  which  he 
did,  led  to  no  such  result  as  we  are  at  present  considering,  and  nothing  more  was  heard  of  the 
subject  until  the  publication  of  Nature-printing  in  its  present  state.  He,  however,  also 
considers  himself  the  undoubted  inrentor  of  Nature-printing,  notwithstanding  what  has  been 
done  by  the  experiment  of  Kyhl  in  1833. 

Mr.  Aitken  too,  about  this  period  was  occupied  in  making  experiments  for  the  orna- 
mentation of  Britannia  metal,  and  also  claims  the  invention,  having  introduced  the  use  of 
natural  objects,  and,  as  he  says,  expressly  for  printing  purposes.  But  Sturges  and  Aitken 
only  followed  Kyhl  in  their  operations,  as  the  one  experimented  with  steel  rollers  for  the 
purpose  of  ornamenting  metallic  surfaces,  while  the  other  applied  the  same  to  printing  pur- 
poses, both  of  which  experiments  were  carried  out  by  Kyhl. 

In  the  Imperial  Printing-Office  at  Vienna,  the  first  application  of  taking  impressions  of 
lace  on  plates  of  metal,  by  means  of  rollers,  took  place  in  tiie  month  of  May,  1852;  accord- 
ing to  Councillor  Auer's  statement  in  his  pamphlet,  it  originated  in  the  Minister  of  the 
Interior,  Ritter  von  Baumgartncr,  having  received  specimens  from  London,  which  so  much 
attracted  the  attention  of  the  Chief  Director,  that  he  determined  to  produce  others  like  them. 
Tins  led  to  the  use  of  gutta-percha  after  the  manner  that  Dr.  Branson  had  used  it ;  but  finding 
this  material  did  not  possess  altogether  the  necessary  properties,  the  experience  of  Andrew 
Worring  induced  him  to  substitute  lead,  which  was  attended  with  remarkable  success.  This 
was,  however,  only  following  in  the  steps  of  Kyhl.  Professor  Ilaidinger,  on  seeing  speci- 
mens of  these  laces,  and  learning  the  means  by  which  they  had  been  obtained,  proposed  the 
application  of  the  process  to  plants. 

The  substitution  of  lead  for  gutta-percha  was  a  great  step  in  the  process,  but  would  have 
been  insufficient  had  not  the  requisite  means  already  existed  for  producing  faithful  co[)ies 
of  those  delicate  fibrous  details  that  were  furnished  in  the  examples  of  botanical  and 
other  figures  in  metal.  These  means  consisted  mainly  in  the  great  perfection  to  which  the 
precipitation  of  metals  upon  moulds  or  matrices  by  electro-galvanic  agency  has  been  brought, 
the  application  of  which — more  generally  known  by  the  name  of  the  Electrotype  pro- 
cess— was  suggested  and  executed  by  Dr.  Branson  in  1851 ;  still  he  met  with  no  signal  suc- 
cess, which  may  be  attributed  to  his  experiments  having  been  conducted  on  a  limited  scale. 

The  firxt  practical  application  of  nature-printing  for  illustrating  a  botanical  woik,  and 
has  been  attended  with  consideral)le  success,  is  to  be  found  in  Chevalier  Von  Ileufler's  work 
on  the  mosses  collected  from  the  valley  of  Arpasch,  in  Transylvania  ;  the  second  (frst  /?*  (/lix 
countnj),  is  a  work  on  the  "  Ferns  of  Great  Britian  and  Ireland,"  by  Thomas  Moore,  in  the 
course  of  publication,  under  the  editorsiiip  of  Dr.  Lindley.  Ferns,  l)y  their  peculiar  struc- 
ture and  general  flatness,  are  especially  adapted  to  develop  the  capal)ilities  of  the  process, — 
and  there  is  no  race  of  plants  wlicre  minute  accuracy  in  (ielineation  is  of  more  vital  impor- 
tance  than  in  that  of  the  ferns;  in  the  distinction  of  wliich,  the  form  of  indentations, 
genera!  outline,  the  exact  manner  in  wliich  rcjieated  subdivision  is  eflccted,  and  especially 
the  distribution  of  veins  scarcely  visil)le  to  the  naked  eye,  play  the  most  important  part. 
To  express  such  facts  with  the  necessary  accuracy,  the  art  of  i)hot()graphy  wotdd  have  been 
insufficient,  until  Nature-printing  was  brought  to  its  pi-esent  state  of  perfection. 

Tiie  l)cautiful  productions  wiiicli  have  been  given  to  the  public  by  Mr.  Henry  Bradbury 
sulTiciently  jjrove  tiie  apiilicability  of  the  processes  which  we  liave  described.  The  coloring 
of  the  plates  lias  been  greatly  improved  by  practice,  and  liy  the  deposition  of  nickel  on  the 
surface  of  the  electrotype  j)latc  the  printei-  has  been  enabled  to  print  off  thousands  of  im- 
pressions without  any  evidence  of  deterioration. 

NICOTINK.  Tliis  alkaloid  is  the  active  principle  of  the  toliaeco  jilant ;  it  was  first 
obtained,  in  an  impure  state,  i\v  Vauquelin  in  1800.  It  is  contained  in  the  dilTerent  species 
of  tobacco,  probably  in  the  state  of  malate  or  citrate.    It  was  obtained  pure  by  Possel  and 


800 


NICOTINE. 


Reimann  from  the  leaves  of  the  Kicotiana  Tabacum,  Macrophylla  rustica,  and  Macrophijlla 
f/hcdiiosa.  Nicotine  and  its  salts  have  been  examined  and  anal)'zed  by  MM.  Oitigasa, 
Barral,  Melsens,and  Schla'sing. 

The  following  is  the  process  employed  by  M.  Schloesing  for  extracting  the  nicotine  from 
the  tobacco.  The  tobacco  leaves  are  exhausted  by  boiling  water,  the  extract  is  then  evap- 
orated till  solid,  or  to  a  syrupy  consistence,  and  shaken  with  twice  its  volume  of  alcohol. 
Two  layers  are  formed,  the  under  layer  is  black  and  almost  solid,  and  contains  some  malate 
of  lime,  the  upper  layer  containing  all  the  nicotine.  This  latter  is  concentrated  by  distilla- 
tion, and  again  treated  with  alcohol  to  precipitate  certain  substances.  This  solution  is 
concentrated,  and  treated  with  a  concentrated  solution  of  potash;  it  is  allowed  to  cool,  and 
is  then  agitated  with  ether,  which  dissolves  all  the  nicotine.  To  the  ethereal  solution  is 
added  powdered  oxalic  acid,  when  oxalate  of  nicotine  is  precipitated  as  a  syrupy  mass.  This 
is  washed  with  ether,  treated  with  potash,  taken  up  with  water,  and  distilled  in  a  salt  bath, 
when  the  nicotine  comes  over,  and  may  be  rendered  pure  and  colorless  by  re-distilling  in  a 
current  of  hydrogen. 

The  following  are  the  quantities  contained  in  the  various  American  tobaccos,  according 
to  M.  Schlocsing : 

100  parts  of  tobacco  dried  at  212° — 

Nicotine. 
Virginia         ..-....-.  6'87 

Kentucky 6-09 

Maryland 2-29 

Havana  (cigarcs  primera),  less  than         ....  2"00 

M.  Melsens  has  observed  the  presence  of  nicotine  in  the  condensed  products  of  tobacco 
smoke.  The  oil  which  is  formed  in  pipes  after  smoking  tobacco  in  them,  and  which  gives 
the  color  to  the  pipe,  contains  nicotine.  The  question  may  then  perhaps  be  asked,  "  If  tobacco 
smoke  contains  such  a  deadly  poison,  why  are  there  not  more  ill  eflects  from  smoking  ?  "  It 
may  perhaps  be  answered  in  this  way :  tobacco  when  smoked  only  yields  about  Visoth  or  less, 
of  its  weight  of  nicotine,  and  then  very  little  of  that  is  condensed  in  the  mouth.  And  again, 
the  system  may  become  accustomed  to  it,  as  is  the  case  with  opium  eaters,  and  then  it 
requires  much  more  to  take  an  effect ;  it  can  scarcely  be  doubted,  though,  that  the  continual 
habit  of  smoking  large  quantities  of  tobacco  is  injurious. 

Nicotine  when  pure  is  a  colorless,  transparent,  oily  liquid,  possessing  an  acrid  odor  and 
an  acrid,  burning  taste.  Its  density  is  1-024,  and  that  of  its  vapor  5-607.  It  restores  the  blue 
color  of  reddened  litmus,  and  renders  turmeric  brown.  It  becomes  yellowish  by  age,  and 
when  exposed  to  the  air  becomes  brown  and  thick,  absorbing  oxygen.  It  is  very  soluble  in 
water,  alcohol,  and  the  oils  (fixed  and  volatile) ;  also  in  ether,  which  has  the  power  of  extract- 
ing it  completely  from  its  aqueous  solution. 

It  is  very  hygrometrical ;  exposed  to  a  moist  atmosphere,  it  rapidly  absorbs  water,  but 
loses  it  again  iii  an  atmosphere  dried  by  potash.  When  thus  hydrated  it  becomes  a  solid 
crystalline  mass  if  exposed  to  the  cold  of  a  mixture  of  ice  and  salt.  "When  anhydrous  it  docs 
not  become  solid  at  14°  F.  It  boils  at  482°  F.,  and  is  at  the  same  time  slightly  decomposed ; 
but  notwithstanding  its  high  boiling  point,  it  may  be  easily  distilled  with  the  vapor  of  water 
without  decomposition. 

The  vapor  of  nicotine  is  so  irritating  that  we  should  experience  a  difficulty  of  breathing 
in  a  room  where  a  drop  of  that  alkaloid  had  been  volatilized.  Its  vapor  burns  with  a  white 
smoky  flame,  depositing  charcoal,  like  an  essential  oil.  Nicotine  turns  the  plane  of  polari- 
zation strongly  to  the  left.  From  the  volume  of  its  vapor,  and  from  the  quantity  of  sulphu- 
ric acid  required  to  form  with  it  a  neutral  salt,  the  formula  of  nicotine  would  appear  to  be 
C^^H'^N" ;  but  from  some  of  its  combinations  it  would  appear  to  be  half  of  this,  viz.,  C"'H''N, 
and  is  so  written  by  some  chemists. 

By  the  aid  of  heat  nicotine  dissolves  sulphur,  but  not  phosphorus.  Nicotine  unites  with 
acids,  forming  salts,  which  are  very  deliquescent,  difficultly  crystallizable,  insoluble  in  ether, 
except  the  acetate,  and  when  pure  possess  no  smell,  but  an  acrid  tobacco  taste.  The  double 
salts  which  nicotine  forms  crystallize  much  more  easily. 

The  aqueous  solution  of  nicotine  is  colorless,  transparent,  and  strongly  alkaline ;  it  forms 
a  white  precipitate  in  a  solution  of  corrosive  sublimate,  also  in  a  solution  of  acetate  of  lead, 
and  with  both  chlorides  of  tin.  The  precipitate  which  it  forms  with  solutions  of  the  salts  of 
zinc  is  soluble  in  an  excess  of  nicotine.  Salts  of  copper  give  with  it  at  first  blue  precipitates, 
but  these  dissolve  in  excess  of  nicotine,  forming  a  deep  blue  solution,  as  they  do  when 
supersaturated  with  ammonia.  Bichloride  of  platinum  yields  with  it  a  yellow  granular  pre- 
cipitate. A  solution  of  permanganate  of  potash  is  immediately  decolorized  by  a  solution  of 
nicotine. 

Fure  concentrated  sulphuric  acid  turns  nicotine  red,  in  the  cold,  and  by  the  application 
of  heat  the  liquid  becomes  thick  and  darker,  and  when  boiled  with  it,  becomes  black,  and 
gives  off  sulphurous  acid. 

With  cold  hydrochloric  acid  it  gives  off  white  fumes,  just  as  ammonia  does ;  when  heated, 
the  mixttu-c  becomes  more  or  less  violet-colored. 


NITROGEN.  801 

Nitric  acid  communicates  to  it,  by  a  gentle  heat,  an  orange  3'ellow  color,  with  disengage- 
ment of  red  vapors  which  become  deeper  as  the  temperature  is  raised,  until  after  prolonged 
ebullition  nothing  but  a  black  mass  remains.  Chlorine  acts  very  strongly  on  it,  disengaging 
hydrochloric  acid  and  yielding  a  blood-red  liquid. 

Iodine  water  preci|)itates  it  of  a  brown  color. 

Nicotine  is  a  most  powerful  poison,  one  drop  put  on  the  tongue  of  a  large  dog  being 
sufficient  to  kill  it  in  two  or  three  minutes. 

The  quantity  of  nicotine  contained  in  any  sample  of  tobacco,  may  be  determined  as 
follows:  about  150  grains  of  tobacco  is  exhausted,  in  a  continuous  distillation  apparatus,  by 
means  of  amraoniated  ether ;  after  driving  off  the  ether  and  ammonia  by  heat,  the  quantity  of 
nicotine  may  be  determined  by  a  standard  solution  of  sulphuric  acid;  500  pts.  of  sulphuric 
acid  (anhydrous  SO^),  neutralizing  2,025  pts.  of  nicotine  {Sc/doe.shif/). — II.  K.  B. 

NITROBENZOLE  (Azobenzole).  C'-fP{NO').  It  is  important  in  the  arts,  both  as  a 
source  of  aniline  for  the  manufacture  of  dye-colors,  and  on  account  of  its  use  for  flavoring 
as  a  substitute  for  oil  of  bitter  almonds,  which  it  closely  resembles  in  flavor  when  pure,  and 
over  which  it  has  the  advantage  of  not  being  poisonous. 

It  is  prepared  from  benzole  (which  see),  by  adding  it  drop  by  drop  to  hot  fuming  nitric 
acid ;  the  nitrobenzole  separates  on  dilution  with  water  in  the  form  of  a  yellowish  oil,  which 
may  be  purified  by  washing  with  water  alone,  or  a  solution  of  carbonate  of  soda.  It  has  a 
density  of  1-209,  at  tiO  F.  (15-5  C),  and  just  above  the  freezing  point  of  water  is 
converted  into  a  crystalline  solid. 

It  is  nearly  insoluble  in  water,  but  alcohol  and  ether  dissolve  it  in  all  proportions. 

Its  conversion  into  aniline  under  the  influence  of  reducing  agents  has  been  before 
mentioned.     See  Aniline. 

Nitrobenzole  may  bo  viewed  as  having  been  derived  from  benzole  C'll",  by  the 
substitution  of  one  equivalent  of  hydrogen  by  the  tetroxide  of  nitrogen,  thus : — 


(  IP 


II.  M.  W. 

NITROGEN.  Detcrmhiation  of  its  jmrity. — The  simplest  and  most  accurate  process 
is  that  of  M.  Bunsen.  The  first  thing  is  to  determine  whether  a  combustible  gas 
containing  oxygen  be  present.  For  this  purpose  it  is  merely  necessary  to  pass  an  electric 
spark  through  the  gas  contained  in  a  eudiometer.  If  the  bulk  remains  unaltered,  the 
absence  of  any  considerable  amount  of  combustible  gas  mixed  with  oxygen  is  proved.  But 
they  may  be  present  in  such  small  quantity,  as  compared  with  the  noncombustible  gas,  that 
no  explosion  can  ensue  on  passing  the  sparks.  It  is  then  necessary  to  add  some  battery  gas 
in  order  to  render  the  mixture  inflammable.  [By"  battery  gas"  is  understood  the  gas 
obtained  by  the  electrolysis  of  water.]  For  the  purpose  of  the  experiment  we  may  add  to 
every  100  volumes  of  the  gas  under  examination  40  volumes  of  battery  gas.  If  the  volume 
after  explosion  be  unaltered  the  total  absence  of  oxygen  and  combustible  gases  is  demon- 
strated. It  is  still  possible  that  the  nitrogen  may  be  contaminated  with  oxygen,  although 
inflammable  gases  are  absent.  To  determine  this  fact  we  must  add  both  hydrogen  and 
battery  gas  in  such  proportions  that  the  volume  of  the  original  gas  plus  hydrogen  is  to  that  of 
the  battery  gas  as  100  :  40.  If  no  oxygen  be  present  the  volume  after  explosion  will  be  that 
of  the  original  gas  and  the  hydrogen.  The  reason  being  that  if  oxygen  had  been  present 
some  of  the  hydrogen  would  have  disappeared  in  order  to  form  Wiiter.  The  nitrogen  gas 
may  still  be  contaminated  by  a  trace  of  a  combustible  gas.  To  determine  this  point,  as 
much  common  air  is  to  be  added  to  the  last  mixture  containing  hydrogen,  as  will  form  a 
detonating  mixture  witli  that  hydrogen.  This  detonating  mixture  so  produced  should  form 
from  2(j  to  (U  per  cent,  of  the  incombustible  gases.  If,  on  making  the  explosion,  it  is 
found  that  two-thirds  of  the  condensation  is  equal  to  the  volume  of  the  hydrogen  added,  it 
will  show  that  no  combustible  gas  was  present,  and  that,  therefore,  the  original  gas  consisted 
of  pure  nitrogen. 

Sj)cc/al  affiniiies  of  nitrogen. — In  the  same  manner  that  ordinary  metallic  substances 
absorb  oxygen  with  avidity  from  the  atmosphere,  especially  at  more  or  less  elevated 
temperatures,  so  other  elementary  bodies  combine  with  nitrogen  to  form  the  nitrides. 
Messrs.  Wohler  and  Sainte-Clair  Deville  have  carefully  investigated  this  subject,  and  with 
great  success.  When  a  mixture  of  titanic  acid  and  cliarcoal  is  heated  in  a  diarcoal  tray 
(contained  in  a  charcoal  tube)  to  a  temperature  sufficient  to  fuse  platinvun,  and  a  current  of 
dry  nitrogen  is  sent  over  the  mixture,  tlic  gas  is  absorbed  with  such  rapitity  that,  no  matter 
how  rapid   tiie  current,  none  escapes  from  the  tube. 

Boron  also  possesses  great  tendency  to  comluue  with  nitrogen  at  high  temperatures. 
Amorphous  boron  heated  in  a  current  of  ammonia  ))ecomcs  incandescent,  the  nitrogen  is 
absorbed  and  the  hydrogen  escapes,  and  may  be  infhuned  at  tlie  exit  of  the  apparatus.  A 
mixture  of  boracic  acid  and  charcoal,  if  ignited  in  a  current  of  nitrogen,  yields  the  white 
infusible  nitrurct  of  boron,  first  desciibed  by  Mr.  ]5almain  under  the  name  of  .iKthogen,  but 
subso((uently  more  accurately  investigated  ]jy  M.  Widiler. 

Silicon  also  combines  with  nitrogen  under  favorable  circumstances.  These  facts,  coupled 
Vol..  III.—.-.' 


802 


NITEO-GLUCOSE. 


with  the  old  experiment  made  by  the  French  chemi.-ts  on  the  nitruret  of  potassium  and 
the  action  of  ammonia  at  a  red  heat  upon  iron,  show  that  nitrogen  is  far  from  being  the 
inert  substance  generally  supposed. — C.  G.  W. 

NITRO-GLUCOSE.  Wlien  we  act  on  finely  powdered  cane  sugar  with  nitro-sulphuric 
acid,  a  pasty  mass  is  first  formed  ;  if  this  be  stirred  for  a  few  minutes  lumps  separate  from 
the  liquid.  When  these  lumps  are  kneaded  in  water  until  every  trace  of  acidity  is  removed, 
they  acquire  a  white  and  silky  lustre  ;  these  are  the  above-named  substance. 

NITRO-MURIATIC  ACID  ;  Aijuaregia  {Acide  nitro-mnriatigiie,  Fr. ;  Salpetersalzsdiire, 
A'dnigsivafiaer,  Germ.) ;  is  the  compound  menstruum  invented  by  the  alchemists  for  dissolving 
gold.  If  strong  nitric  acid,  orange-colored  by  saturation  with  nitrous  or  hyponitric  acid,  be 
mixed  with  the  strongest  liquid  hydrochloric  acid,  no  other  effect  is  produced  than  might 
be  expected  from  the  action  of  nitrous  acid  of  the  same  strength  upon  an  equal  quantity 
of  water ;  nor  has  the  mixed  acid  so  formed  any  power  of  acting  upon  gold  or  plati- 
num. But  if  colorless  concentrated  nitric  acid  and  ordinary  hydrochloric  acid  be  mixed 
together,  the  mixture  immediately  becomes  yellow,  and  acquires  the  power  of  dissolving  these 
two  noble  metals.  Sir.  E.  Davy  seems  first  to  have  obtained  a  gaseous  compound  of  chlo- 
rine and  binoxide  of  nitrogen  in  1830,  and  a  combination  of  these  two  constituents  was 
distilled  from  ay«rt  rcc/ia,  and  liquefied  by  M.  Baudrimont  in  1843.  But  it  was  not  until  M. 
Gay-Lussac  investigated  the  subject  {Annalea  de  C'/iimie,  3me,  ser.  xxiii.  203;  or  Chemi- 
cal Gazct/c,  1848,  p.  'irtO)  that  the  true  nature  of  the  mutual  action  of  nitric  and  hydro- 
chloric acids  was  fully  explained.  When  these  two  acids  are  mixed  in  a  concentrated 
state,  a  reaction  soon  commences,  the  licjuid  becomes  red,  and  effervescence  takes  place, 
from  the  escape  of  chlorine  and  a  chloronitric  vapor.  On  passing  this  gaseous  mixture 
through  a  U  tube,  the  bent  part  of  which  is  immersed  in  a  freezing  mixture  of  ice  and  salt, 
the  chloronitric  compound  is  condensed  as  a  dark-colored  liquid,  and  is  thus  separated  fron 
the  chlorine  which  accompanied  it. 

CJdoro-idtric  acid,  NO'^Cl^,  may  be  represented  as  a  peroxide  of  nitrogen,  in  which  two 
equivalents  of  oxygen  are  replaced  by  two  equivalents  of  chlorine.  This  chloro-nitric  acid 
does  not  take  any  part  in  the  dissolving  of  gold  and  platinum,  which  is  effected  by  the 
chlorine  alone.  Chloro-nitric  acid  may  also  be  formed  by  mixing  the  two  gases,  binoxide 
of  nitrogen  and  chlorine,  in  equal  volumes,  which  assume  a  brilliant  orange  color,  and  suffer 
a  condensation  of  exactly  one-third  of  their  original  volume.  Another  compound  of  chlorine 
and  binoxide  of  nitrogen  always  appears  simultaneously  with  this  in  variable  proportons. 
Its  composition  is  N0"C1,  and  may  be  represented  as  nitrous  acid  (NO^),  in  which  one 
equivalent  of  oxygen  has  been  replaced  by  one  of  chlorine.  It  is  a  vaporous  liquid,  possess- 
ing similar  properties  to  the  other,  but  having  a  much  greater  vapor  density. 

The  theoretical  vapor  density  of  the  chloro-nitric  acid  is  1.74,  and  that  of  the  chloro- 
nitrous  acid  2.259. 

The  vapors  of  both  these  compounds  are  decomposed,  when  conducted  into  water,  into 
hydrochloric  acid  and  hyponitric  acid  or  nitrous  acid.  They  are  also  decomposed  by 
mercury,  the  chlorine  combining  with  the  metal,  leaving  pure  binoxide  of  nitrogen. 

Various  proportions  of  nitiic  and  hydrochloric  acids  arc  used  in  making  acjua  regia ; 
sometimes  two  or  three  parts,  and  sometimes  six  parts  of  hydrochloric  acid  to  one  part  of 
nitric  acid  ;  and  occasionally  chloride  of  ammonium,  instead  of  hydrochloric  acid,  is  added  to 
nitric  acid  for  particular  purposes,  as  for  making  a  solution  of  tin  for  the  dyers.  An  aqua 
regia  may  also  be  prepared  by  dissolving  nitre  in  hydrochloric  acid. — H.  K.  B. 

NITROUS  ACID  (XO^;  equivalent,  38),  is  obtained  by  mixing  four  measures  of  binoxide 
of  nitrogen  WMth  one  measure  of  oxygen;  they  unite  and  form  an  orange-red  vapor,  which 
wlien  exposed  to  a  temperature  of  0°  Fahr.  condenses  to  a  thin  mobile  green  liquid.     It  is 
decomposed  by  water,  and  is  converted  into  nitric  acid  and  binoxide  of  nitrogen. 
8X0= -^  HO  =r  UNO' -f  2X01 

On  this  account  it  cannot  be  made  to  unite  directly  with  metallic  oxides ;  the  salts  of 
this  acid  are  therefore  obtained  by  an  indirect  process.  Nitiate  of  Potash,  when  exposed 
to  a  high  temperature,  is  decomposed,  losing  oxygen  and  becoming  nitrate  of  potash  ;  some 
caustic  potash  is  also  formed  at  the  same  time.  To  obtain  it  pure,  this  is  dissolved  in  water, 
ar.d  while  boiling  we  add  nitrate  of  silver,  when  we  obtain  first  of  all  a  dark  pveci]iitate  of 
oxide  of  silver,  caused  by  the  caustic  potash;  which  is  separated  by  a  filter,  and  on  cooling 
the  liquid  the  nitrate  of  silver  crystallizes  in  white  needles,  whicli  may  be  purified  by 
recrystallization.  From  this  salt  the  pure  nitrites  may  be  obtained;  for  instance,  by  adding 
to  a  solution  of  nitrate  of  silver  chloride  of  potassium,  we  obtain  the  potash  salt, 
AgNV-f  KCl  =  AgCl  +  KXO  \ 

Htponttric  Acid  (NO*,  equivalent  40)  is  best  procured  by  distilling,  in  a  coated  glass 
retort,  perfectly  dry  nitrate  of  lead.  Hyponitric  acid  and  oxygen  pass  over  into  a  receiver, 
surroimded  with  a  freezing  mixture ;  the  former  condenses  into  a  liquid,  while  the  oxvgen 
passes  off'  by  the  safety  tube,  and  only  oxide  of  lead  remains  in  the  retort.  This  hyponitric 
acid  ov  peroxide  of  niiro(jen  is  a  liciuid,  colorless  at — 4°  Fahr.,  but  is  at  higher  temperatures 


NUTRITION  8U3 

yellow  and  orange-.  It  boil?!  at  82"  Fahr.,  giving  off  a  dark  red  vapor,  which  becomes  almost 
black  when  further  heated.  A  beautil'ul  lead-salt  of  this-  acid  lias  been  discovered  by 
M.  Peligot.  It  is  formed  by  digesting  a  dilute  solution  of  nitrate  of  lead  with  finely  divided 
metallic  lead  at  a  temperature  between  150'  and  170  Fahr.  See  Lire's  Chemical  JJlc- 
tiouari/. — H.  K.  B. 

NUTRITION,  or  the  process  for  promoting  the  growth  of  living  beings,  occupies  a  most 
important  position  in  the  study  of  physiology,  and  in  the  important  piactical  question  of 
health.  In  some  of  the  more  succulent  plants  we  observe  that  they  increase  in  volume 
after  detachment  from  their  parent  soil,  by  the  absorption  of  the  nutriment  which  they  find 
in  the  atmosphere,  viz.,  oxygen,  vapor  of  water,  carbonic  acid,  and  ammonia.  But  all 
these  are  gaseous  bodies  or  vapors,  while  the  plant  itself  is  a  solid.  Hence  we  infer  that 
such  a  plant  is  capable  of  reducing  gases  to  a  solid  form,  and  of  thus  increasing  in  bulk  and 
weight.  It  appears  that  all  plants  are  similarly  endowed,  and  that  they  mainly  subsist  by 
feeding  on  the  gases  which  surround  them,  by  converting  these  elastic  fluids,  assisted  by  the 
elements  of  the  soil,  by  means  of  the  organs  with  which  they  are  supplied,  into  the  solid 
forms  of  the  vegetable  kingdom,  so  endless  in  figure,  but  yet  so  lovely  that  the  greatest 
familiarity  only  renders  them  objects  of  superior  admiration.  When  we  turn  to  the  animal 
world  we  find  that  the  individuals  of  which  it  is  composed  are  incapable  of  condensing  gases. 
The  least  educated  person  knows  that  animals  cannot  subsist  on  air,  but  that  tliey  require 
to  imbibe  solid  matter,  which,  by  research,  it  has  been  found  must  be  similar  to  that  of 
which  they  themselves  consist.  Hence  an  animal  may  be  defined  to  be  a  being  which 
subsists  by  appropriating  to  itself  food  similar  to  the  matter  of  which  its  own  body  is 
composed.  A  reason  is  thus  found  for  its  locomotion ;  while  a  plant  finding  its  nourishment 
in  the  air  in  which  it  is  immersed,  has  its  food  brought  to  it  by  the  usual  laws  of  inanimate 
nature.  In  some  of  the  lower  parts  of  the  animal  scale  it  has  been  found  that  matter  exists 
(cellulose)  identical  with  that  supposed  to  be  peculiar  to  vegetables,  and  hence  it  may  be 
probable,  that,  as  nature  is  simple  in  her  works,  the  animated  world  consists  of  a  chain, 
formed  of  a  series  of  beings,  passing  down  in  regular  gradation,  from  comparatively  the 
most  perfect  to  the  most  imperfect  state ;  the  lowest  plant  being  closely  allied  to  the  lowest 
form  of  animal.  If  this  be  so,  it  will  at  once  be  obvious,  that  to  say  where  jilants  begin  and 
animals  end,  cannot  be  a  problem  of  easy  solution.  But  even  in  the  higher  classes  of 
animals,  sub.stances  usually  considered  characteristic  of  vegetable  life  have  been  recently 
believed  to  have  been  detected.  But  the  occurrence  of  such  materials  in  the  animal 
structure  upon  a  limited  scale,,  might  be  possibly  accounted  for  by  processes  of  reduction,  so 
peculiarly  the  distinguisliing  feature  of  the  chemistry  of  animals,  rather  than  by  constructive 
means,  such  as  denotes  the  result  of  vegetable  activity. 

The  determination  of  the  proper  food  for  animals  is  a  great  experiment,  and  must  be 
guided  by  the  light  of  science.  In  reference  to  the  human  race,  we  must  carefully  study 
the  habits  and  the  results  of  the  instinct  of  the  inferior  animals  subsisting  on  similar  aliment. 
For  it  is  evident  that  there  are  certain  laws  which  natundly  regulate  the  lower  beings  in  the 
choice  of  their  food.  It  would  ije  a  phenomenon  to  hear  of  the  suicide  or  accidental  death, 
from  choice  of  food,  of  a  domesticated  animal,  still  more  so,  of  that  of  a  creature  which  is 
free  to  roam  amid  the  wild  scenes  of  nature.  We  can  recall  but  an  isolated  case  of  the 
failure  of  animal  instinct  witli  regard  to  the  selection  of  food.  It  was  in  the  instance  of  a 
pony  which  swallowed  a  quarter  of  an  ounce  of  dried  and  powdered  monkshood  {AvonHnm 
napellm).  The  animal  suffered  considerably,  as  if  under  an  attack  of  glanders,  for  a  few 
hours.  But  these  occurences  are  so  rare  that  it  might  almost  be  affirmed  that  man  is  the 
only  created  being  which  disobeys  the  laws  of  nature.  It  is  merely  when  domesticated,  and 
under  circumstances  analogous  to  those  in  which  man  himself  is  placed,  that  we  find  the 
inferior  creation  imitating,  by  such  experiments,  the  examiJe  of  their  more  godlike 
superiors. 

The  consideration  of  the  subject  of  nutrition  comprehends  the  nature  of  nutriment  or 
food,  and  of  its  change  into  blood,  and  into  the  solitis  and  fluids  of  the  animal  structure. 
Food  is  required  in  proportion  to  the  wear  and  tear  of  the  body.  The  waste  which  tlie 
animal  system  thus  undergoes  varies  with  the  age  and  tlie  labor  to  which  the  animal  is  sub- 
ji'cted.  IIii)i)ocratcs  knew  that  children  are  more  affected  by  abstinence  than  young 
|):;i-.-;ons,  these  more  tiian  tlie  middle-aged,  and  the  latter  more  than  old  men.  In  conform- 
ity with  this  ob.servation,  Dante  has  framed  the  stirring  incidents  in  the  story  of  Count 
Ugolino,  a  nobleman  of  Pisa,  who  was  confined,  witii  his  four  .'•ons,  in  the  dungeon  of  a 
towei',  the  key  of  wliich  ))eing  east  into  the  river  Arno,  they  were,  in  tliis  horrible  situation, 
starved  to  death.  On  the  fourth  morning,  tlie  youngest  child  "sunk  in  death,"  while  the 
others  followed  "  one  by  one."  From  tin;  history  of  the  .slave  traffic  we  learn  that  inaiiy  of 
the  poor  Africans,  torn  from  tiieir  country  and  friend.s,  oflt'ii  ])ref'er  death  in  various  forms 
to  a  life  of  bondage.  Some  of  them  have  l)een  known  to  starve  themselves  to  death  ;  and 
in  two  ca-ses,  in  which  tlie  details  arc  graphically  supplied,  the  pains  of  the  sufferer  were 
terminated  "in  eight  or  ten  days,"  while  in  the  other  case  the  mortal  scene  was  closed  on 
the  ninth  day.     [Dr.  Trotter,  Mr.   Wilson,  IIW,  Farliain.  Com.)     An  interesting  incident 


804  NUTRITION. 

has  been  recorded  of  a  North  American  Indian,  the  last  of  his  tribe,  which  had  been  thus 
almost  extinguished  by  small-pox.  He  resolved  to  die  ;  and,  abstaining  from  all  nutriment, 
perished  on  the  ninth  day.  (C'atlin.)  In  order  to  study  the  nature  of  the  process  of  nutri- 
tion, we  are  obliged  to  take  advantage  of  all  the  avenues  to  knowledge  which  present 
themselves,  in  viewing  the  animal  system.  One  of  the  readiest  means  seems  to  be,  to  as- 
certain how,  without  the  use  of  food,  the  built-up  animal  loses  weight,  languishes,  and  dies, 
under  the  conditions  of  inanition ;  and  for  this  purpose  we  have  too  frequent  opportunities 
among  the  children  of  the  poor  in  ill-ventilated,  lowly  dwellings;  or  we  may  experiment 
upon  an  inferior  animal,  ascertain  daily  its  loss  of  weight  by  absence  of  nutriment,  and 
after  the  lapse  of  a  sufficient  period,  feed  it  with  aliment  carefully  analyzed.  The  gradual 
change  in  the  weight  occasioned  by  the  passage  of  the  food  from  the  stomach  into  the 
circulation,  is  then  to  be  watched,  and  the  further  influence  on  the  system  by  its  disappear- 
ance in  the  form  of  excretions,  and  of  expiration  by  the  lungs  and  skin.  Death  is  occasion- 
ed in  the  instances  related,  by  starvation,  as  it  is  termed  in  common  language.  In  other 
words,  the  oxygen  which  a  human  being  is  compelled  to  introduce  into  his  lungs  daily,  to 
the  extent  of  3'2|  ounces,  combines  with  the  carbon  and  hydrogen  of  the  solid  tissues  of  the 
body,  to  be  expired  in  tlie  form  of  carbonic  acid.  The  amount  of  carbon  actually  consumed 
has  been  found  to  be  IS'/iu  ounces.  The  consumption  of  the  carbon  and  hydrogen  in  each 
animal  must  depend  on  the  oxygen  introduced  by  respiration.  Hence  the  child,  as  in  the 
tragedy  of  Dante,  whose  respiratory  organs  are  in  great  activity,  requires  a  more  frequent 
supply  of  food,  and  in  greater  abundance,  than  an  adult.  A  bird  deprived  of  food,  dies  on 
the  third  day ;  while,  a  serpent — which,  when  confined  in  a  bell  jar  of  air  consumes  in  an 
hour  so  little  oxygen  that  the  carbonic  acid  formed  is  inappreciable — can  live  without  food 
for  three  months  or  longer.  {Licbig.)  It  has  been  found  that  turtledoves,  when  kept  with- 
out solid  food  for  seven  days,  lost  4'12  per  cent,  of  their  weight,  and  2696  per  cent,  of 
caibon  by  respiration,  having  exhaled  daily  3'722  per  cent,  when  fed  on  millet;  the  ex- 
crements weighed  '21  per  cent,  of  the  weight  of  the  body.  {Boussingmdt^  Ann.  C/iim.  3 
ser.  11,  433.)  Other  researches  have  shown  that  mammalia  lose  daily  in  starvation  4  per 
cent.,  thus  affording  a  mean  of  4^2  per  cent,  of  their  weight.  (Cfiossaf.)  A  cat,  weighing 
about  90  ounces  (2,572  grammes),  died  on  the  eighteenth  day  of  starvation,  losing  daily  2-87 
per  cent,  of  its  weight ;  the  total  loss  being  51 '7  percent,  of  its  weight.  {Bidder  and  Schmidt.) 
The  deductions  which  have  been  made  from  this  experiment  are  that  the  cat  lost  1264 '8  gram- 
mes of  its  weight,  which  consisted  of  200'43  grammes  of  muscle,  132'75  grammes  of  fat, 
and  927"65  grammes  of  water.  In  another  experiment,  a  cat  weighing  3047'8  grammes 
had  injected  into  its  stomach  daily  1 50  grammes  of  water.  The  trial  was  continued  for  a  week, 
during  which  the  animal  lost  438  grammes,  or  62"57  grammes  daily,  a  less  diminution  of 
weight  than  when  no  water  was  supplied  ;  and  hence  we  can  understand,  in  some  measure, 
the  facts  which  have  been  detailed  of  protracted  cases  of  starvation  under  the  influence  of 
water.  Of  the  different  parts  of  the  body  which  relatively  sustain  diminution  of  weight  in 
these  instances,  it  appears  that  the  blood  undergoes  the  greatest  loss,  or  about  93 '7  per 
cent,  of  its  weight  during  the  18  days,  the  pancreas  85-4  per  cent,  the  fatty  tissue  80-7  per 
cent.,  muscles  and  tendons  06-9  per  cent.,  brain  and  spinal  cord  37"6,  bones  14'3  per  cent., 
kidneys  only  6"2  per  cent,  of  each  of  their  original  weights.  Hence  the  loss  of  weight  In 
starvation  is  chiefly  experienced  in  the  muscles,  the  blood,  and  the  fiit.  Half  of  the  loss 
may  be  referred  to  the  muscular  tissue,  a  quarter  to  the  fat,  and  the  remaining  quarter  to  all 
the  other  organs.  It  seems  to  be  principally  the  products  of  decomposition  of  the  muscles 
and  of  the  Wt  which  are  represented  in  the  excretions.  "With  reference  to  the  form  in 
which  these  portions  of  the  animal  frame  disappear  from  the  system  in  the  excretions  and 
exiialations,  it  appears  that  the  daily  loss  of  muscle  undergone  by  an  animal  was  '611  per 
cent,  of  its  weight,  while  the  fat  was  "422  per  cent.  These  yielded  2'16  per  cent,  carbonic 
acid,  1'6  per  cent,  of  aqueous  vapor  through  the  skin,  '20  per  cent,  of  urea  in  the  urine, 
•008  per  cent,  sulphuric  acid,  "001  per  cent,  of  phosphoric  acid,  "029  per  cent,  inorganic 
constituents  of  the  urine,  '080  per  cent,  dry  ftBces  (including  '02  per  cent,  of  bilious  matter), 
and  2'24  per  cent,  of  fluid  water  removed  with  the  urine  and  fieces.  {Op.  cit.)  Such  is  the 
elucidation,  so  f^iras  it  has  been  carried  by  experiment,  of  the  results  of  starvation,  and  of 
the  nature  of  the  products  which,  by  the  influence  of  the  atmosphere,  are  thrown  off  from 
the  animal  system.  The  next  object  of  interest  which  has  attracted  attention,  has  been  the 
increase  of  an  animal  in  weight  and  bulk.  An  experiment  on  a  cat,  weighing  2177  gram- 
mes, has  shown  that  the  animal  in  eight  days  consumed  1886-7  grammes  of  flesh,  27.4 
grammes  of  fat,  and  increased  in  weight  by  337  grammes.  During  the  experiment,  62"36 
grammes  of  nitrogen  were  eliminated  by  the  urine.  It  was  calculated  that  the  increase  in 
weight  depended  partially  on  the  deposition  in  the  system  of  40-16  grammes  of  muscular  mat- 
ter from  the  food  of  143'42  grammes  of  fat,  178  grammes  salts  with  sulphur,  and  134-15 
grammes  water.  Such  researched  being  made  with  pure  animal  matter  as  food,  it  is  easy 
to  perceive  that  the  increase  of  the  animal  depends  on  the  simple  assimilation  or  deposition 
of  the  animal  matter  already  formed  ;  but  when  an  animal  becomes  fat  by  the  consumption 
of  vegetables,  the  question  of  the  origin  of  the  muscle  and  fat  from  such  a  source  becomes 


NUTRITIOK 


805 


a  legitimate  subject  of  discussion.  The  nitrogenous  matter  of  vegetables  has  now  been 
identitied  with  similar  bodies  found  in  animals,  and  therefoi-e  we  can  readily  account  for 
the  supplj^  of  the  waste  of  muscle,  by  the  assimilation  of  nitrogenous  vegetable  food.  The 
origin  of  the  fat  in  animals  fed  on  the  produce  of  plants  is  not  so  obvious. 

John  Hunter  had  long  ago,  in  his  admirable  observations  on  bees,  found  {Phil.  Trans. 
vol.  Ixxxii.  128,  1792)  that  these  creatures  collect  farina  or  pollen,  deposit  it  at  the  bottom 
of  their  cells,  and  that  other  bees  knead  it  and  "  work  it  down  into  the  bottom,"  or  spread 
it  over  what  was  deposited  there,  before  converting  it  into  the  consistence  of  paste  (bee- 
bread)  ;  this  he  discovered  in  the  interior  of  the  maggots ;  he  therefore  infers  that  it  is  the 
food  of  this  early  condition  of  the  bee,  and  is  not  intended  "  to  make  wax."  The  bees  when 
caught  returning  home,  were  ibuiid  with  the  line  transparent  terminal  gullet-bag  full  of 
honey.  When  examined  on  going  out  in  the  morning  this  bag  was  empty,  from  which 
Hunter  concluded  that  the  honey  was  either  regurgitated  for  preservation  as  future  aliment, 
or  passed  into  the  stomach.  He  shows  that  the  bee  bread  is  not  wax,  and  concludes  that 
"the  wax  is  formed  by  the  bees  themselves;  it  may  be  called  an  external  secretion  of  oil, 
and  I  have  found  that  it  is  formed  between  the  scales  of  the  under  side  of  the  belly."  On 
examining  the  bees  through  a  glass  hive  while  they  were  climbing  up  the  glass,  he  could  see 
that  most  of  them  had  this  substance,  for  it  looked  as  if  the  lower  or  posterior  edge  of  the 
scale  was  double,  or  that  there  were  double  scales,  but  he  perceived  it  was  loose,  not  attach- 
ed. Finding  that  the  substance  brought  in  on  their  legs  was  farina,  intended,  as  appeared 
from  every  circumstance,  to  be  the  food  of  the  maggot,  and  not  to  make  wax,  and  not  hav- 
ing yet  perceived  any  thing  that  could  give  the  least  idea  of  wax,  he  conceived  these  scales 
might  be  it,  at  least  he  thought  it  necessary  to  investigate  them,  and  therefore  took  several 
on  the  point  of  a  needle,  and  held  them  to  a  candle,  when  they  melted  and  immediately 
formed  themselves  into  a  round  globe ;  on  which  he  no  longer  doubted  that  this  was  the 
wax,  which  opinion  was  confirmed  by  not  finding  those  scales  but  in  the  building  season 
{ib.).  It  is  a  remarkable  circumstance  that  foreign  chemical  physiologists  who  have  interest- 
ed themselves  in  this  question,  and  who  have  merely  confirmed  Hunter's  observations,  omit 
to  mention  even  his  name,  while  they  notice  that  of  Huber,  a  subsequent  inquirer. 

But  that  the  oil  of  the  food  is  incapable  of  supplying  the  fat  of  the  animal,  or  of  the 
butter  of  milk,  is  clearly  established.  One  of  the  earliest  experiments  on  this  subject  may 
be  cited : — two  cows  were  found  to  have,  in  the  total  food  consumed,  10"094  lbs.  of  oil  and 
wax,  while  the  butter  of  the  milk  amounted  to  72.26  lbs.,  and  the  oil  and  wax  in  the  dung 
was  52-5  lbs.;  showing  an  excess  of  23'82  lbs.  of  oil  in  the  butter  and  dung  over  what 
originally  existed  in  the  food.  Tlie  conclusion  is  inevitable  that  starch  and  sugar,  assisted 
by  the  nitrogenous  matter,  must  have  yielded  fatty  material. — R.  D.  JJiompson,  Trans. 
Med.  Cldrarg.  Sac,  1846,  vol.   xxix. 

According  to  the  present  views  of  those  best  acquainted  with  this  subject,  the  non-nitro- 
genous food  is  that  which  is  especially  destined  for  the  production  of  animal  heat,  the  oxy- 
gen of  the  air  yielding  heat  when  it  unites  with  its  carbon  and  hydrogen.  "  The  heat 
which  is  produced  by  respiration  is  similar  to  that  which  is  produced  by  the  inflammation  of 
combustible  bodies,  with  this  difference,  that  in  the  latter  instance  the  fire  is  separated  from 
the  air,  in  the  former  from  the  blood."  (Adair  Craivford's  E.rpcr.  on  Animal  Heat,  1779, 
p.  76.)  It  is  to  Crawford  that  the  theory  of  animal  heat  is  usually  attributed.  The  French 
claim  the  honor  for  Lavoisier.  There  is  no  doubt  that  the  latter  was  engaged  with  the  sub- 
ject about  the  same  period,  but  the  date  of  his  publication  is  doubtful,  as  at  that  period 
French  writings  were  usually  ante-dated.  The  doctrine  of  animal  heat,  as  ^riginally  sug- 
gested by  Crawford,  still  stands  its  ground.  All  the  arguments  opposed  to  it  are  merely 
trifling  attacks  upon  little  indentations  in  the  great  curve,  which  expresses  the  average 
theory.  When  we  compare  the  staple  articles  of  food  with  the  blood,  we  shall  find  in  the 
latter  fluid  corresponding  bodies  to  those  constituting  the  nutriment,  as  appears  in  the  fol- 


lowing parallel  columns : — 


Milk. 


Nitrogenous 
matter  - 


Non-nitrogen- 
ous matter 


Salts . 


Casein. 
Albumen. 


Butter. 


',    Butt 
1   Sugn 


Flour. 
Fibrin. 
Gluten. 
Casein. 
Albumen. 


Oil. 

Starch. 


Blood. 
Fibrin. 

Casein. 
Albumen. 
Globulin. 
Coloring  matter. 
Fats  and  oils. 
Sugar. 


Chloride  of  potassium. 

"        of  sodium. 
Sulphate  of  soda. 
Carbonate  of  soda. 
Piiosphate  of  soda. 

"         of  lime. 

"  of  magnesia. 

"  of  iron. 


>■     Ditto.      }-      Ditto. 


806 


NUTRITION. 


Lme  of  the  Balance  of  the  Food. — The  older  opinions  respecting  the  nature  of  nutrition 
seems  to  have  been  that  the  stomach  and  digestive  organs  possessed  the  power  of  assimi- 
hxtion,  as  it  was  termed.  Although  this  expression  might  still  be  used  in  a  restricted  sense, 
the  former  meaning  which  was  attached  to  it  was  of  a  much  more  extensive  nature,  and 
implied  a  power  in  the  animal  system  which  we  now  know  is  not  possessed  by  it.  Indeed, 
a  comparatively  slight  acquaintance  with  medical  writers,  up  to  even  a  recent  date,  is  suf- 
ficient to  teach  us  that  a  belief  existed  that  almost  any  species  of  organic  matter,  when 
s\ibjectcd  to  the  assimilating  powers  of  digestion,  could  be  rendered  serviceable  in  the  sup- 
port of  the  body.  The  great  discovery  of  Beccaria  in  1742,  in  his  analysis  of  flour,  ought 
to  have  produced  a  greater  revolution  in  dietetics  than  it  appears  to  have  done.  He  first 
observed,  that  if  wheaten  flour  be  washed  with  water  on  a  sieve,  the  water  becomes  milky 
by  the  mechanical  diff"usion  of  the  starch,  which  in  time  subsides,  while  a  material  like  glue, 
which  is  not  miscible  with  water,  remains.  He  termed  the  portion  carried  away  by  the  water 
starch,  and  the  soft  tenacious  residue  he  denominated  gluten  (now  known  to  consist  of 
fibrin,  gluten,  casein).  He  identified  the  starch  with  vegetalile  matter,  while  the  glutinous 
portion  appeared  to  be  endowed  with  the  character  usually  attributed  to  animal  matter,  and 
this  led  him  to  propose  two  very  simple  tests  by  which  the  vegetable  and  animal  substances, 
that  is,  matters  containing  nitrogen,  may  be  readily  discriminated.  When  vegetable,  or 
non-nitrogenous  bodies  are  digested  in  water,  they  do  not  putrefy,  but  ferment  and  yield  as 
a  product  a  vinous  or  an  acid  fluid.  With  these  starch  corresponds.  Animal  substances,  on 
the  other  hand,  under  the  same  conditions,  putrefy  and  corrupt,  and  afford  a  urinous  or 
ammoniacal  fluid.  Again,  distillation  supplies  a  valuable  distinguishing  test  of  the  products 
of  the  two  kingdoms.  Vegetable  or  non-nitrogenous  matter,  when  subjected  to  this  opera- 
tion, yields  an  acid  product,  and  a  heavy  black  oil,  similar  to  pitch.  Such  are  the  characters 
of  starch.  Gluten,  like  animal  or  nitrogenous  bodies,  affords  an  alkaline  spirit — a  volatile 
alkaline  salt  (carbonate  of  ammonia),  first  a  yellow,  then  a  black  oil,  and  finally  there  is  left, 
by  intense  heat,  a  black  spongy  matter  (charcoal),  which  in  an  open  fire  becomes  a  white 
insoluble  earth  (bone  earth).  These  remarkable  observations  struck  Beccaria  with  surprise, 
as  he  found  no  traces  of  any  such  results  in  previous  writers.  For  when  he  had  discovered 
gluten  by  the  iiimple  process  already  detailed,  it  appeared  to  him  so  identical  with  animal 
matter  that,  if  he  had  not  himself  extracted  it  from  wheat,  he  should  have  mistaken  it  for 
a  product  of  the  animal  world.  {Hist,  de  VAcad.  df  Bofo(/ne.  Collect.  Acad.  x.  1.)  These 
views,  which  are  in  exact  consonance  with  the  most  recent  ideas  entertained  by  chemical 
physiologists,  appear  to  have  produced  little  fruit,  although  the  question  put  by  the  author, 
"Are  we  composed  of  other  substances  than  those  which  serve  for  our  nourishment?"  dis- 
tinctly exhibits  the  view  which  he  took  of  the  subject.  Duiing  the  present  century,  a  large 
amount  of  experiment  has  clearly  demonstrated  that  animals  cannot  subsist  on  starch, 
s)igar,  or  other  foods  destitute  of  nitrogen  ;  and  therefore  the  inference  was  fairly  deduced 
that  the  animal  system  possessed  no  power  of  assimilating  nitrogen  from  the  air.  {Magendie.) 
Furtlier  consideration  led  to  the  conclusion  that  milk  constitutes  the  type  of  what  nutriment 
should  be,  since  it  is  supplied  for  animal  support  by  nature  at  the  earliest  period  of  human 
existence  (Prout),  and  contains  nitrogenous  matter,  oil,  and  sugar.  Afterwards,  experi- 
ments were  made  to  determine  the  amount  of  nitrogen  in  food,  and  the  relative  value  of 
nutriment  was  tabularly  stated,  in  dependence  on  the  ratio  of  nitrogen  present  in  each 
species  {Bowmbuiault,  An7i.  de  Chim.  Ixiii.  225,  1836),  a  method  which  has  been  super- 
seded. It  was  svibscquently  inferred  that  nitrogenous  matter  supplied  the  waste  of  the 
muscular  tissue,  while  the  non-nitrogenous  constituents  of  the  food  served  for  respiratory 
purposes,  or  the  production  of  animal  heat  by  obviating  the  too  rapid  transformation  of  the 
muscular  elements  of  the  body.  {Liebig.,  Orc/anUchc  Chemie,  1842.)  This  was  the  true  key 
to  the  solution  of  the  problem  as  to  the  function  of  the  nitrogenous  and  non-nitrogenous 
food,  and  it  laid  open  a  wide  field  for  inquiry  in  reference  to  the  application  of  rational 
systems  of  dieting  to  the  animal  system.  For  example,  it  was  found  in  a  series  of  experi- 
ments conducted  for  the  British  Government  in  1845,  that  in  a  stall-fed  cow  in  one  day, 
taken  from  an  average  of  several  months,  the  amount  of  food  conveyed  into  the  circulation 
of  the  blood  of  the  animal,  was  14-56  lbs.  weight,  and  when  the  nature  of  this  mass  of  nutri- 
ment was  subjected  to  chemical  inquiry,  it  appeared  that  1-50  lbs.  consisted  of  nitrogenous 
matter,  and  13  lbs.  of  non-nitrogenous  food.  When  the  relation  between  these  two  quanti- 
ties is  calculated,  it  results  that  the  nitrogenous  is  to  the  non-nitrogenous  food  as  1  to  8.33, 
as  in  the  case  of  an  animal  at  rest.  This  observation  led  to  researches  into  the  relative 
constitution  of  food  as  employed  by  different  nations  ;  and  the  deduction  was  made  that  it 
is  a  law  of  natuie  that  animals,  under  the  different  conditions  of  rest  and  exertion,  require 
food  in  which  the  relation  of  the  nutrient  or  nitrogenous  food  is  different  in  reference  to  the 
non-nitrogenous  or  heat-producing  (calorifiant)  constituent: — that  the  animal  system  may 
t)e  viewed,  as,  in  an  analogous  condition  to  a  field,  from  which  diiferent  crops  extract 
different  amounts  of  matter,  which  must  be  ascertained  by  experiment ; — an  animal  at  rest 
consuming  more  calorifiant  food,  in  relation  to  the  nutritive  constituents,  than  an  animal  in 
full  exercise.     From  the  analyses  then  instituted  the  following  table  was  constructed. 


NUTRITION. 


8or 


Approximate  relation  of  nutritive  or  nitrogenous  to  calorifiant  matter . — 

Kelation  of  Nutritive  to 
CaloritiaDt  Matter. 

Milk  food  for  a  growing  animal lto2 

Beans 1  "       2^ 

;Pp^    ^     I 1  "      3 

Linseed     ) 

Scottish  oatmeal         -        -        -        -        -        -        -     1  "      5 

Wheat  flour     1  f    1  "      Y 

Semolina    -       I  p^^^  ^^^  ^^  ^^^^j  ^^  ^^^^  .         J        ^^ 

Indian  corn  i    "      c 

Barley        -      J  I 

Potatoes 1"9 

East  India  rice -         -     1  "    10 

Dry  Swedish  turnips 1"11 

Arrowroot    1 

Tapioca        [• 1  "    26 

Sago  ) 

Starch  1  "    40 

These  proportions  will  consequently  vary  considerably  according  to  the  richness  of  the 
grain  or  crop,  and  hence  similar  tables  which  have  been  subsequently  published  by  others 
will  be  found  to  differ  in  some  of  the  details  from  the  preceding  data ;  but  the  facts  now 
stated — given  as  approximate — are  probably  as  good  averages  as  could  be  selected. — R.  Z>. 
Thompson,  Mcdico-Chirurgical  Trans,  xxix.  and  Experim.  Researches  on  the  Food  of 
Anhnals,  1846,  p.  162. 

A  consideration  of  the  nature  of  the  relations  exhibited  in  this  table  is  sufficient  to 
afford  an  explanation  of  many  practical  results  in  the  subject  of  diet.  Thus  in  the  young 
of  the  mammalia — including  the  human  race — the  heat-forming  or  non-nitrogenous  food 
is  only  two  or  three  times  greater  than  that  of  the  nitrogenous  food  which  is  the  supporter 
of  the  muscular  tissue  of  the  body,  because  the  child  requires  a  larger  amount  of  matter  to 
repair  its  daily  waste,  and  likewise  an  additional  portion  to  enable  it  to  increase  in  bulk. 
Nature  has  so  arranged  that,  in  the  milk  of  the  mother,  every  three  or  four  ounces  of  the 
solid  particles  of  that  fluid  shall  supply  one  ounce  of  nitrogenous  material.  When  we 
compare  this  result,  which  is  a  fact  independent  of  all  theoretical  considerations,  with  the 
condition  of  the  class  of  starches  at  the  close  of  the  table — known  under  the  names  of 
arrow-root,  tapioca,  and  sago — we  see,  that  to  supply  these  to  children  would  be  to  deprive 
them  of  the  possibility  of  obtaining  the  requisite  nourishment  demanded  by  the  wants  of 
their  systems ;  since  to  communicate  one  ounce  of  nitrogenous  matter  to  them,  it  would  be 
necessary  that  they  should  swallow  26  ounces  of  starch,  a  proceeding  which,  upon  mechani- 
cal considerations  alone,  would  be  impracticable.  Beans  and  peas  have  been  found  much 
more  effective  in  supporting  the  strength  of  animals  subjected  to  hard  labor  than  grass  or 
other  soft  fodder ;  and  the  reason  for  this  on  the  principles  under  review  is  obvious.  A 
cow  weighing  about  1,000  pounds  was  found  to  introduce  into  its  system  15'28  pounds  of 
the  solid  portions  of  grass  daily ;  but  this  was  extracted  from  100  pounds'  weight,  of  fresh 
grass,  and  contained  r56  pound  only  of  nitrogenous  matter,  and  13'1  of  heat-forming  or 
respiratory  food.  To  convey  this  large  mass  of  nutriment  into  the  stomach  required  the 
action  of  the  primary  organs  of  digestion  during  the  whole  day ;  while  to  have  introduced 
a  similar  amount  of  nitrogenous  matter  in  the  shape  of  beans,  not  above  20  pounds  would 
probably  have  been  necessary.  Thus  by  subsituting  the  concentrated  form  of  beans  for  the 
bulky  grass,  a  great  saving  of  time  is  effected  in  conveying  the  digestive  materials  into  the 
current  of  the  blood.  The  bulky  nature  too  of  grass — f^rora  100  lbs.  of  which  only  15f 
pounds  of  nutritive  matter  can  be  extracted — affords  an  explanation  of  the  more  complicat- 
ed nature  of  the  stomachs  of  ruminant  animals  than  of  the  luiman  family,  which  practical 
experience,  or  instinct,  as  some  would  term  it,  has  taught  to  select  more  concentrated  forms 
of  food. 

Thcprimary  and  original  food  of  man,  whatever  speculators  may  say  to  the  contrary, 
is  milk,  a  fluid  of  purely  animal  origin.  If  those  who  are  to  regulate  diet  are  not  guided 
by  scientific  knowledge,  and  do  not  exercise  their  judgment,  they  might  be  inclined  to  draw 
from  this  fact  tiie  inference,  that  the  proper  nutriment  of  man  is  animal  food.  This  dediic- 
.tion  might  be  defended  with  some  show  of  reason  to  the  exclusion  of  a  vegetable  diet.  But 
observation  having  proved  that  animals  can  subsist  upon  a  vegetable  as  well  as  upon  an 
animal  regimen,  and  scientific  research  having  satisfactorily  demonstrated  that  the  constitu- 
ents of  the  two  kinds  of  nutriment,  when  well  selected,  are  identical,  the  one-sided  position 
must  yield  to  the  light  of  knowledge. 

It  will  be  now  from  these  details,  in  some  measure,  understood  how  it  happens  that  for 
all  conditions  of  society,  vegetable  food  may  not  be  advi.sable ;  and  that  vogctarianism,  while 
it  may  be  applicable  in  some  instances,  would  be  prejudicial  in  other  individual  cases.     The 


808 


NUTRITION. 


poetical  and  merciful  sympathies  of  Pythagoras  it  is  impossible  altogether  to  set  aside, 
ahhough  it  is  unnecessary  to  echo  tlie  sentiment  that  "  the  man  of  cultivated  moral  feeling 
shrinlis  from  tlie  talking  the  life  of  the  higher  grade  of  animals,  and  abhors  the  thought  of 
inflicting  pain  and  sheddhig  blood ;  "  for  even  the  Greek  philosopher,  although  he  objected 
to  slay  cattle  lor  the  purposes  of  human  food,  sacriticed,  in  a  tit  of  enthusiasm,  without  any 
compunction,  one  hundred  oxen  in  commemoration  of  his  discovery  that  a  square  on  the 
hypothenuse  of  a  riglit-angled  triangle  is  equal  to  the  sum  of  two  squares  on  the  base  and 
the  perpendicular.  Indeed,  such  a  cruel  result  of  a  scientific  discovery  has  appeared  to  his 
admirers  so  inconsistent,  as  to  induce  them  to  suggest  that  the  oxen  were  made  of  wax.  It 
is  more  probable  tliat,  as  in  modern  times,  other  causes  had  tended  towards  a  vegetarian 
conclusion.  But  his  arguments  may  be  heard:  "Forbear,  mortals,  to  pollute  your  bodies 
with  abominable  food.  Wild  beasts  satisfy  their  hunger  with  flesh,  although  not  all ;  for  the 
horse,  flocks,  herds,  feed  on  grass.  But  "those  which  have  a  wild  and  ciuel  temper,  Arme- 
nian tigers,  angry  lions,  bears,  and  wolves  rejoice  in  bloody  food.  What  a  wicked  crime  it 
is  that  bowels  should  be  buried  in  Ijowels,  and  that  one  greedy  body  should  fatten  on 
another  crammed  into  it,  and  one  animal  should  live  by  the  death  of  another!" — Ovid, 
Metcwiorph.  xv.  2. 

A  practical  application  of  the  law  involved  in  the  table  to  the  nourishment  of  horses 
will  now  be  understood.  If  we  represent  the  amount  of  muscle  removed  from  the  body  of 
a  horse  to  be  2  lbs.  per  day,  while  the  amount  of  food  consumed  in  the  production  of  heat 
is  12  lbs.,  it  is  obvious  that,  to  make  up  for  this  loss,  we  should  never  think  of  giving  to  the 
animal  food  containing  2  lbs.  of  albuminous  or  muscular  matter  and  52  lbs.  of  non-nitrogen- 
ous or  heat-forming  matter,  such  as  sago;  neither  should  we  give  a  diet  containing  2  lbs  of 
albuminous  materials  and  22  of  calorifiant  ingredients,  such  as  turnips;  but  we  should 
endeavor  to  administer  nourishment  which  contained  as  nearly  as  possible  the  ingredients 
which  the  animal's  consumption  required.  This  object  would  be  nearly  attained  by  the  use 
of  oats,  which  would  give  ior  every  2  Ib.s.  of  muscular  material,  10  lbs.  of  heat  forming 
constituents;  or  by  barley  2  to  14.  A  mixture,  then  of  the  two  grains  would  supply  the 
nourishment  required  by  the  animal,  or  the  same  result  would  follow  by  the  employment  of 
beans  and  hay.  The  principle  of  the  arrangement  of  the  food  being  understood,  the  nature 
of  the  nutriment  can  be  easily  calculated  for  the  different  conditions  in  which  the  animal 
may  be  placed. 

A  continuous  study  of  the  table  brings  us  to  oatmeal,  which  constitutes,  even  at  the 
present  day,  an  essential  element  in  the  support  of  the  Scottish  peasant.  W^heat  is  no  doubt 
cultivated  to  a  greater  extent  than  formerly,  in  northern  latitudes,  but  from  the  analyses 
which  have  been  published,  it  ajipears  to  be  an  undoubted  fact  that  the  amount  of  nitrogen 
increases,  within  certain  limits,  in  this  species  of  the  cerealia  as  the  plant  advances  from 
the  equator.  But  one  cause  of  the  high  nitiogenous  position  held  by  oatmeal  is,  that  as  it 
is  usually  prepared,  it  retains  much  of  the  bran,  which  is  rich  in  nitrogen ;  while  in  the  pre- 
dominant form  of  wheat-flour  this  ingredient  is  in  a  great  measure  removed.  When,  however, 
the  bran  is  retained  in  the  flour,  as  when  the  entire  wheat-seed  is  ground  up  and  not  sifted, 
the  superiority  of  the  nutritious  value  of  oatmeal  over  wheat-flour  has  not  been  demonstra- 
ted. The  substance  termed  semolina  in  the  table,  consists  of  bruised  wheat  from  the  south 
of  Europe,  and  corresponds  with  the  manna  croup  of  the  north  of  Europe,  and  the  soojee  of 
India.  Illustrations  of  the  fatal  effects  of  this  practice  have  been  afforded  by  feeding  calves 
on  sago,  a  form  of  farinaceous  matter,  as  exhibited  by  the  table,  which  is  artificially  dis- 
turbed in  its  natural  equilibrium.  For  it  will  be  remembered  that  arrow-root,  tapioca,  and 
sago,  as  they  occur  in  commerce,  are  the  starches  of  natural  flours  which  have  been  washed 
by  repeated  applications  of  water,  until  they  have  been  to  a  great  extent  deprived  of  their 
nitrogenous  matter,  and  of  their  saline  ingredients.  Calves  fed  on  this  form  of  food,  have 
been  observed  to  become  most  ready  victims  to  passing  epidemics.  {Smith  of  Dcanstove.) 
For  a  brief  period  they  seem  not  to  suffer,  but  on  the  approach  of  disease  they  were  readily 
subjected  to  its  action,  and  rarely  recovered.  The  same  reasoning  will  apply  to  the  human 
species.  For  if  a  child  were  fed  on  milk  entirely  (its  composition  being  1  nutiitive  to  2 
heat-forming,  the  proper  blood  salts),  and  throve  as  nature  intended  it  should  do  on  this 
species  of  aliment,  could  we  expect  that  the  inf\xnt  would  be  equally  nourished,  >vhen  a 
portion  of  this  type  of  food  was  replaced  by  arrow-root,  containing  1  nutritive  to  26  of 
calorifiant  material,  without  any  saline  ingredients  rcfiuiied  to  produce  blood?  To  expect 
such  a  result  would  be  opi)osed  to  experience  and  to  all  analogy.  From  the  table  we  may  infer 
that  the  food  destined  for  an  animal  in  full  exercise,  should  range  between  milk  and  wheat- 
flour,  according  to  the  nature  and  extent  of  the  demands  upon  the  system.  Milk  may  there- 
fore be  employed  with  a  certain  amount  of  the  cerealia  with  probable  advantage.  When 
the  food  is  preserved  by  nature,  by  means  of  combining  water,  as  in  succtdcnt  vegetables, 
from  the  severe  effects  of  the  vicissitudes  of  the  atmosphere,  the  most  efficient  nutriment  is 
aflbrded  to  the  inferior  animals.  This  is  shown  in  the  following  table,  where  an  average  is 
given  of  the  products  of  two  cows,  in  milk  and  butter,  by  dift'erent  species  of  aliment.  The 
largest  amount  is  obtained  from  grass,  which  preserves  its  equilibrum  most  firmly  during 


Butter  in 

Nitrosen  in  Food 

5  days. 

in  5  daj-s. 

lbs. 

lbs. 

3-50 

2.32 

3-43 

3-89 

3-20 

3-34 

3-44 

3-82 

3-48 

414 

3-72 

5-27 

NUTPJTIO:?^.  809 

the  changes  of  the  seasons,  while  hay  and  cereal  crops,  from  their  want  of  succulence,  and 
therefore  of  protection  from  the  rain  and  fermenting  influences,  are  less  influential  in  ett'ect- 
ing  a  steady  product. 

Milk  in 

5  days, 
lbs. 

1.  Grass    -         -         -  114 

2.  Barley  and  hay      -  107 

3.  Malt  and  hay  "       -  102 

4.  Barley,  molasses  and  hay  107 

5.  Barley,  linseed,  and  hay  108 

6.  Beans  and  hay      -  108 

It  had  been  found  by  experiment,  that,  not  only  in  hay-making  is  the  coloring  matter 
of  the  grass  removed  or  altered,  but,  particularly  in  moist  districts,  the  sugar  or  heat-forming 
portion  of  this  form  of  provender  is  washed  out.by  the  rains  or  destroyed  by  fermentation, 
wliile  a  certain  proportion  of  the  soluble  salts  absolutely  refjuired  for  the  production  of 
animal  blood  and  milk  is  also  removed  by  every  shower  which  falls  during  the  drying  of  the 
hay.  In  this  table,  the  butter  and  milk  of  the  cow  may  be  supposed  to  represent  the  increase 
of  bulk  which  a  gi'owing  animal  sustains  during  its  infant  years;  while  the  richness  of  these 
forms  of  dairy -produce  are  the  well-recognized  tests  of  the  value  of  the  soil  and  pasturage 
upon  which  the  animals  have  browsed.  By  a  comparison  of  the  relation  of  the  different  kinds 
of  cerealia  we  may  improve  one  species  by  mi.xing  it  with  another.  By  mi.xing  one-third  of 
Canada  flour  with  two-thirds  of  Indian  corn,  a  very  good  loaf  is  produced,  and  when  equal 
parts  of  flour  and  oatmeal,  or  of  barley,  or  of  pea-meal  are  employed,  a  nourishing  bread  is 
formed.  Beneficial  results  have  also  followed  from  the  admi.xturc  of  two  or  three  different 
kinds  of  grain,  and  many  of  these  forms  of  bread  might  be  substituted  with  advantage  for 
wheat  flour  in  peculiar  conditions  of  the  system.  The  superior  advantage  of  good  wheat  flour 
depends  on  the  presence  of  gluten,  an  adhesive  nitrogenous  principle,  which,  during  fermen- 
tation by  the  resistance  which  it  presents  to  the  escape  of  the  carbonic  acid,  engenders  that 
vesicular  spongy  condition  which  is  considered  the  test  of  a  good  loaf  From  the  absence 
of  this  substance  in  other  kinds  of  grain,  they  are  of  themselves  incapable  of  affording  a 
spongy  loaf,  and  hence  the  presence  of  wheat  floiu-  is  essential  in  all  well-raised  bread.  A 
loaf  may  be  made  of  equal  parts  of  oatmeal  and  flour,  which  when  fermented  will  be  highly 
spongy.  It  is  advisable  in  such  a  case  to  use  foreign  flour,  which  contains  a  larger  propor- 
tion of  adhesive  gluten  than  is  found  in  the  wheat  flour  grown  in  our  northern  climate.  It 
may  be  objected  that  the  recommendation  of  such  mixture  is  a  direct  invitation  to  bakers 
to  adulterate  their  flour.  But  such  mixtures  are  admitted  by  law  with  the  provision  that 
the  letter  M  be  affixed  by  the  baker  to  the  loaf.  Indian-corn  bread  may  be  baked  of  good 
quality  by  a  smaller  admixture  of  flour  than  is  necessary  when  oatmeal  is  the  other  ingre- 
dient. For  this  purpose  it  should  be  reduced  to  a  fine  meal,  in  smaller  particles  than  is 
practiced  in  the  United  States.  It  may  then  be  mixed  with  one-third  its  weight  of  i)est  floirr, 
and  be  fermented  in  the  usual  way.  When  thus  baked,  the  best  Indian-corn  bread  is  always 
dark  colored,  and  cannot  be  made  much  lighter  than  coarse  wheat  bread.  The  shade  of 
color  is  yellowish.  When  Indian-corn  bread  appears  white,  the  conclusion  to  be  drawn  is 
that  the  mixture  consists  of  more  than  one-third  of  wheat  flour.  Even  wlien  one-half  its 
weight  of  wheat  flour  is  added  to  it,  Indian-corn  exhibits  in  the  mixture  its  characteristic 
dark  tint.  See  Bread.  The  position  which  potatoes  hold  in  the  nutritive  scale,  shows  that 
although  they  are  frequently  used  in  the  mode  of  preparing  bread  by  fermentation,  no  advan- 
tage would  be  gained  by  augmenting  their  amount,  since  the  aliment  would  thus  be  render- 
ed more  dilute  and  the  statement  of  the  poet  confirmed  : — 

"  Bread  has  been  made  (indifferent)  from  potatoes." — Stjron. 

At  the  present  day  the  Xew  Zealanders  are  affected,  to  the  extent,  in  some  districts,  of 
20  per  cent.,  in  others  of  10  per  cent.,  with  external  marks  of  scrofula,  a  fact  whit'h  was  not 
observed  by  Capt.  Cook.  This  disease  is  theiefore  inferred  to  be  a  modern  innovation, 
brought  about  by  the  natives  having  lived  since  Cook's  time  on  potatoes,  which  have  super- 
seded fish  and  pig's  flesh  in  a  great  measure.  It  is  only  necessiuy  to  sec  a  child  after  a 
mouth's  residence  in  the  house  of  a  European,  to  have  an  indication  of  the  magic  influence 
better  diet  would  have  on  the  whole  race.  The  puny  limbs  of  the  young  savage  grow  stout, 
the  protuberant  belly  disappears,  and  traces  of  red  blood  can  be  seen  through  the  nut-col- 
ored skin  of  his  infant  face. — A.  S.  Thdmsini'a  Xrw  Zralntid,  i.  2ir>. 

Further  support  of  the  law  enunciated  has  been  afforded  l)y  subsequent  experiments 
{Freseinus,  Knapp,  Plai/fnir,  Licbi(j).  "  A  glance  at  these  relations  is  sufficient  to  convince 
us  that  in  choosing  his  food  (when  a  ciioice  is  open  to  him),  and  in  mixing  the  various  articles 
of  diet,  man  is  guided  by  an  unerring  instinct  which  rests  oir  a  law  of  nature.  TJiis  law  pre- 
scribes to  man  as  well  as  to  animals  a  proportion  between  the  plastic  ami  non-nitrogenous  con- 
stituents of  his  whole  diet,  which  is  fixed  within  certain  limits  within  which  it  may  vary  accord- 


810 


NUTRITION". 


ing  to  his  mode  of  life  and  state  of  body.  This  proportion  may,  in. opposition  to  the  law  of 
nature  and  iu.-;tinct,  be  altered  beyond  these  limits  by  necessity  or  compulsion,  but  this  can 
never  happen  witiiout  endangering  the  health  and  injuring  the  body  and  mental  powers  of 
man.  It  is  the  elevated  mission  of  science  to  bring  this  law  of  nature  home  to  our  minds; 
it  is  her  duty  to  show  why  man  and  animals  require  such  an  admixture  in  the  constituents 
of  their  food  for  the  support  of  the  vital  functions,  and  what  the  influences  are  which  deter- 
mine in  accordance  with  the  natural  law  changes  in  this  admixture."  {Liebig,  Fam.  Letters 
on  Cliem'tHtry,  1851,  p.  362.)  It  has  been  shown  that  when  a  French  soldier  is  fed  on  1  lb. 
h^h  oz.  of  bread,  he  consumes  in  this  ration  1  part  of  nitrogenous  to  4|  of  non-nitrogenous 
material  (Knapp),  and  that  when  pigs  were  fed  on  potatoes  no  augmentation  could  be  detect- 
ed in  their  weight.  An  increase  was  observed  when  the  diet  of  the  animal  was  potatoes, 
butter-milk,  whey,  and  kitchen  refuse,  but  the  greatest  improvement  took  place  under  what 
was  termed  a  fattening  fodder,  consisting  daily  of  9'74  lbs.  potatoes;  ground  corn  9  lbs. ;  rye- 
meal  "64  lbs. ;  peas,  '68  lbs.  ;  butfer-milk,  whey,  and  kitchen  refuse  "92  lbs.  {Boussingaidt). 
In  these  different  modes  of  dieting,  the  following  were  the  relations  of  the  constituents  of  the 
food: 

Nitrogenous.  Kon-nitrogenous. 

Potatoes 1  to  8| 

Mixed  food  .         .         -         .         i  "  v;,, 

Fattening  fodder  -         -         -         1  "  5^ 

The  German  farmer  renders  the  proportion  more  nearly  allied  between  the  proximate  prin- 
ciples of  the  potato,  by  fermenting  and  distilling  from  them  a  spirit,  and  giving  the  residue 
thus  supplied  with  a  le.ss  proportion  of  heat-forming  material  to  his  cattle.  It  has  been 
supposed  in  other  countries  that  the  German  agriculturist  is  a  distiller.  On  the  contrary 
the  production  of  spirit  is  a  result  of  what  he  has  found  to  be,  by  experience,  a  valuable 
method  of  improving  the  alimentary  character  of  the  potato  {Knapp).  All  of  these  expla- 
nations have  been  deduced  since  the  law  of  the  equilibrum  of  the  food  detailed  above  was 
detected. 

The  tables  on  the  next  page  are  illustrations  of  the  same  law. 

In  these  tables  the  ounces  of  the  original  are  calculated  as  grammes,  and  the  last  column 
gives  the  relation  of  the  nitrogenous  or  flesh-forming  part  of  the  food,  to  the  non-nitrogenous 
or  heat-producing  ingredients  of  the  aliment,  instead  of,  as  in  the  original,  the  proportion 
between  the  carbon  of  these  constituents  of  the  food  being  estimated.  The  table  is  read  thus : 
an  English  soldier  consumes  weekly  11,703  grammes  (a  gramme  equal  to  15'44  grains)  of 
food.  In  this  food  1,119  grammes  are  nitrogenous  or  flesh-forming  matter ;  3,937  non-nitro- 
genous or  heat-producing  material;  152  mineral  substance;  the  organic  matter  containing 
2,219  grammes  carbon.  The  relation  of  the  nitrogenous  to  the  non-nitrogenons  matter  is  as 
1  to  3 "50.  From  this  table  the  results  have  been  deduced  that  soldiers  and  sailors  consuming 
35  ounces  of  nitrogenous  or  flesh-forming  food  weekly,  and  70  to  74  ounces  of  carbon,  the 
proportion  of  the  carbon  in  the  flesh-forming  to  that  in  the  respiratory  or  heat-forming 
iood  is  as  one  to  three.  Older  persons  require  only  25  to  30  flesh-forming  matter  weekly, 
and  from  72  to  78  respiratory  food ;  the  relation  of  the  carbon  in  these  is  as  1  to  5.  Bos'S 
of  from  ten  to  twelve  years  of  age  require  17  ounces  of  flesh-forming  matter,  the  relation  of 
the  carbon  in  the  flesh-forming  to  the  heat-producing  aliment  being  as  1  to  5i.  In  work- 
houses and  jails,  less  heat-producing  matter  is  consumed,  in  consequence  of  the  shelter  and 
heat  supplied  artificially  to  the  inmates.  In  prisons,  where  hard  labor  is  in  force,  the  con- 
sumption of  flesh-forming  or  nitrogenous  nutriment  increases.  It  has  been  estimated  that  in 
a  man  weighing  140  lbs.,  the  weight  of  the  flesh-forming  matter  of  the  blood  is  4  lbs.,  that 
of  tlie  muscular  ti.ssue  27+  lbs.,  and  in  the  bones  5  lbs.,  making  a  total  of  364  lbs.,  and  that 
in  the  course  of  18  weeks  these  364  lbs.  are  introduced  into  the  system.  (Plaiifair,  New 
Edin.  Phil.  Journal,  1854,  56,262.)  The  author  of  this  elaborate  and  valuable  table  has 
justly  remarked  that  the  old  mode  of  estimating  the  value  of  dietaries,  by  merely  giving  the 
total  number  of  ounces  of  solid  food  used  daily  or  weekly,  and  quite  irrespective  of  its  com- 
position, is  most  erroneous;  and  he  quotes  an  instance  of  an  agricultuial  laborer,  in  Glou- 
cestershire, who  in  the  year  of  the  potato  famine  subsisted  chiefly  on  flour,  consuming  ]()3 
ounces  weekly,  wliich  contained  26  ounces  of  flesh-forming  matter.  Wiien  potatoes  became 
cheaper,  he  returned  to  a  potato  diet,  and  now  ate  321  ounces  weekly,  although  they  con- 
tained of  true  nutriment  only  about  8  or  10  ounces.  A  comparison  of  the  six  pauper 
dietaries  formerly  recommended,  with  the  difference  between  tlie  salt  and  fresh  meats  diet- 
ary of  the  sailor,  &(?.,  have  no  relation  in  equivalent  nutritive  value,  but  merely  rely  on 
al)solute  weight  alone.  It  is  l)y  such  dietaries,  where  the  proper  balance  of  the  constituents 
is  not  preserved,  tiiat,  although  the  appetite  may  be  satisfied,  the  waste  of  the  system  is  not 
adequately  repaired.  The  health  may  appear  not  to  be  affected  in  the  absence  of  epidemics, 
but,  under  such  a  dietary  as  that  alluded  to,  a  maximum  of  labor  cannot  be  obtained  from 
a  workman ;  a  frail  constitution  is  engendered,  which  acts  as  a  fertile  soil  to  miasmata  of 
various  kinds.  Tliese  seeds  ofdisea.se  taking  root,  are  rapidly  developed  into  maladies,  like 
the  rank  fungi  of  damp  and  dismal  cellai-s. 


NUTKITION. 


811 


Weekly 
Con- 
sump- 
tion. 


Dietaries  of  Soldiers  and  Sailors. 

English  soldier    -      _  - 

"           "       in  India  -  -  " 

"        sailor  (fresh  meat)  - 

"           "      (salt  meat)  -  -  - 

Dutch  soldier,  in  war  -  -  -  - 

'<■           "       in  peace  -  •  " 

French  soldier     -         -  -  -  " 

Bavarian  soldier  -         -  •  -  ■ 

Hessian  soldier    -         -  -  •  ■ 

Dietaries  of  Children. 

Christ's  Hospital,  Hertford  - 
"  London    - 

Chelsea  Hospital  boys'  school 
Greenwich  Hospital  " 

Dietaries  of  Aged  Persons. 
Greenwich  pensioners  - 
Chelsea  "  -         -         - 

Gillespie's  Hospital,  Edinburgh    - 
Trinity  Hospital  " 

Dietaries  of  Aged  Poor. 
1st  class      ------ 

2d       " 

3d       " 

4th     " 

5th     " 

6th     " 

3fean  of  all  Enr/lish  counties 
St.  Cuthbert's,  Edinburgh  - 
City  poorhouse         "  ... 

Dietaries  of  English  Prisons. 
2d  class,  above  7  not  above  21  days     - 
3(j  "         21  "  6   weeks' 

hard  labor      .         .         .         - 
4th,  Ith,  8th  classes,  above  6  weeks' 

not  above  4  months'  liard  labor 
5th  class,  above  4  months'  hard  labor  - 

Bengal  Prisons. 

Without  labor 

With  labor  -         -         -         - 
Contractor's  insufficient  diet 

BoMnAY  Prisons. 
I  All  classes,  without  hard  labor     - 
With  hard  labor 

Arctic  anp  other  Dietaries. 

Esquimaux 

Yaout  ..---- 

Boschesmen 

Hottentots  ------ 

Farm  laborers,  Gloucestershire     - 

"  Dorsetshire  -         -         - 

"  Dharwar,  Bombay — re- 

turn in  Bombay  Prison  Dietaries    - 


Grms. 

11703 
9080 
9350 
8978 
6130 

11857 

10742 
7492 

13096 


6687 
7488 
7585 
7151 


8328 

10278 

4829 

5944 


5418 
3312 


Nitro- 
genous 
Matter. 


Grms. 

1119 

1057 

1078 

1274 

1090 

759 

1029 

652 

712 


631 
534 
401 
570 


757 
905 
651 
G08 


626 
463 
488 
595 
479 
454 
681 
458 
412 


Non- 
nitro- 
genous 
Matter. 


Mineral 
Constit- 
uents. 


6393 

9144 

8405 
10092 


6935 
9464 
5185 


47a 

565 

649 
628 


571 

872 
393 


5634   667 
6935   1103 


5065 
3548 


7740 
3093 
1777 
1323 
825 
631 


Grms. 
3937 
3195 
3185 
4092 
3160 
3306 
3955 
3161 
4210 


1897 

2378 
2888 
2685 


3784 
3487 
2858 
3014 


2743 

2773 
3092 
3617 
2988 
2725 
3065 
2766 
1547 


6749   434 


Carbon. 


3463 

3827 

3900 
4042 


5051 

5917 
4209 


3142 

3987 


39628 
19814 
11393 
12384 
3299 
2243 

4280 


Grms. 

152 

74 

98 

187 

57 

128 

143 

103 


76 

88 

183 

81 


109 

144 

73 

104 


101 
89 
121 
123 
111 
88 

102 
54 


107 

125 

156 
131 


64 
92 

40 


63 
76 


Relation 
of  nitro 
genous 
to  non- 
nitro- 
genous 
Matter. 


34 

30 


Grms. 

2219 
2053 
2184 
2706 
2293 
2191 
2639 
1933 
2384 


1213 
1453 
1785 
1637 


2242 
2416 
2210 
1774 


1681 
1582 
1716 
2101 
1694 
1535 
1796 
1454 
975 


As  1  to 

3-50 
3-02 
2-95 
3-69 
2-90 
4-35 
3-84 
4*85 
5-91 


3-57 


K 


1834 
2091 


2162 
2270 


2364 
2819 


4-45 
7-20 
4-71 


4-87 
3-85 
4-39 
4-95 


4-38 
5-99 
6-33 
6-08 
6-24 
6-00 
4-50 
6-04 
3-75 


7-34 
6-77 


6-00 
6-43 


8-85 
6-78 


1899  10-71 


2130 
2800 


34830 
29907 
17182 
18699 
2323 
1601 

1905 


2-08 
3-61 


5-12 
6-46 
6-41 
9-30 
3-97 
3-55 

9-86 


812 


NUTRITIOX. 


Fat  animal. 

Lean  animal 

-     12-5 

12-8'7 

-     33- 

25-3 

-       3- 

45 

-     51-5 

57-33 

When  the  constitution  of  the  food  is  compared  in  its  relations  of  muscular  to  fatty  mat- 
ter, with  the  proportion  of  these  ingredients  deposited  in  animals,  the  result  .is  of  interest. 
Carefully  conducted  experiments  on  the  large  scale  upon  animals  have  shown,  that  in  fat 
animals  killed  and  carefully  analyzed  after  death,  the  carcass  of  the  fat  ox  contained  1  part 
of  nitrogenous  matter  to  2^  fat ;  in  that  of  the  fat  sheep  the  relation  was  1  to  4  ;  in  that 
of  the  very  fat  sheep,  1  to  6  ;  and  in  the  moderately  fat  pig,  1  to  5.  In  the  lean  sheep  the 
proportion  was  1  to  1+;  in  the  lean  pig,  1  to  2.  The  average  composition  of  such  well  fat- 
tened and  lean  animals  was  found  to  be  nearly 

Nitrogenous  matter     ... 

Fat 

Mineral  matter  -         •         •        - 
"Water        .         .         -         -         , 

100-00  100-00 

It  was  found  by  an  analysis  of  some  of  the  most  important  animals  fed  and  slaughtered  as 
human  food,  that  the  entire  bodies,  even  when  in  a  reputed  lean  condition,  may  contain 
more  dry  fat  than  dry  nitrogenous  substances.  Of  the  animals  ripe  for  the  butcher,  a  bul- 
lock and  a  lamb  contained  rather  more  than  twice  as  much  dry  fat  as  dry  nitrogenous  mat- 
ter; while  in  a  very  fat  pig  and  sheep,  the  proportion  was  1  muscular  matter  to  4  fat,  and 
in  a  moderately  fat  sheep  the  fat  was  three  times  greater  than  the  nitrogenous  matter. — 
Zaices  and  Gilbert,  Proc.  Royal  Society,  No.  32,348. — June,  1858. 

Use  of  Fermented  Liquid.'i  in  Nutrition. — In  the  very  earliest  periods  of  human  history 
wine  appears  to  have  been  known,  and  to  have  been  of  the  same  nature  with  that  which  we 
now  use,  as  the  Hebrew  term  employed  to  designate  the  stimulating  liquor  indicates  it  as 
being  derived  from  a  fermenting  origin,  (Pareuit.  Antiq.  Ileb.  396.)  This,  together  with 
its  wide-spread  use,  has  frequently  been  considered  as  an  argument  in  l\ivor  of  its  necessity. 
But  its  ubiquity  cannot  be  substantiated.  The  native  Indians  of  North  America,  amount- 
ing to  some  millions  in  number,  were  unacquainted  with  fermented  products  until  they  were 
visited  by  the  white  man,  {Catlin.)  When  the  Spaniards. first  visited  South  America,  they 
were  astonished  at  the  constitutional  temperance  of  the  natives,  which,  in  their  opinion,  far 
exceeded  the  habits  of  the  most  mortified  hermits,  {Robertson,  iv.)  In  Patagonia,  within 
the  last  200  years,  the  inhabitants,  when  offered  a  bottle  of  brandy,  would  not  drink,  {Sir  J. 
Karhrough,  in  1669,  8vo.  1711,  p.  50.)  If  we  refer  to  Africa,  we  have  the  authority  of  the 
great  traveller  who  has  penetrated  into  the  interior  of  that  mysterious  continent,  that,  true 
to  their  faith,  the  Mohammedans  "  drink  nothing  but  water,"  [Park,)  and  it  is  only  among 
the  Pagan  negroes  who  have  frequent  intercourse  with  the  coast  in  consequence  of  these 
being  the  reservoirs  from  which  slavery  emanates,  and  in  such  senii-civilized  towns  as 
Tripoli,  that  religion  is  placed  in  subjection  to  inebriating  indulgences,  and  that  "  drunken- 
ness is  more  common  than  even  in  most  towns  in  England,"  (Lyon.)  It  is  true  that  the 
ancient  Gauls  and  Germans,  who,  however,  were  somewhat  civilized,  made  use  of  beer,  but 
whether  they  did  so  habitually,  or  to  excess,  before  they  were  contaminated  l)y  Roman  cus- 
toms, seems  unlikely.  Certain  it  is,  that  they  had  no  wine  of  their  own.  Tiie  Gauls  pur- 
chased their  wine  chiefly  from  Italy,  and  were  exceedingly  fond  of  it,  {Diodori'n,)  and  hence 
they  are  said  to  have  been  invited  into  that  country  by  the  delicacy  of  the  Italian  wines, 
{Livy,  V.  33.)  Even  among  the  Romans,  however,  in  the  virtuous  days  of  the  RepuVjlic, 
strong  drinks  were  not  universally  in  favor,  since  it  was  fashionable,  in  order  to  make  wine 
keep,  to  boil  it  down  to  one-half,  (Virr/il,')  or  one-third,  {P/iny\)  in  other  words,  to  distil 
away  all  the  alcohol  it  contained.  All  the  circumstances,  indeed,  with  which  we  are  ac- 
quainted, seem  to  support  the  view  of  the  historian,  that  "  it  is  in  polished  societies  where 
intemperance  undermines  the  constitution,"  (Robertaon.)  These  facts  seem  to  prove  that 
alcohol  is  not  a  necessary  of  life.  It  remains  to  consider  what  its  influence  is  upon  the  sys- 
tem. When  fluids  containing  alcohol  are  introduced  into  the  body  of  animals,  the  amount 
of  carbonic  acid  evolved  from  the  lungs  speedily  begins  to  dimini,sh.  The  influence  of  even 
a  small  portion  of  wine  begins  to  be  appreciable  in  a  very  short  space  of  time  after  it  has 
been  swallowed,  so  that  we  infer  its  power  in  this  respect  to  be  almost  consentaneous  with 
its  arrival  in  the  stomach.  Alcohol  itself  possesses  a  similar  effect,  and  the  use  of  porter  is 
attended  by  the  same  results.  Numerous  experiments  have  demonstrated  that  alcoliol  in 
every  state,  and  in  every  quantity,  uniformly  lessens,  in  a  greater  or  less  degree,  the  quan- 
tity of  carbonic  acid  elicited  according  to  the  quantity  and  circumstances  under  which  it  is 
taken.  When  taken  on  an  empty  stomach,  its  eff'ects  are  remarkable ;  the  depression  is 
greatest  almost  instantaneously  ;  after  a  short  time,  however,  the  powers  of  the  constitution 
appear  to  rally,  then  it  sinks  again,  and  afterwards  .slowly  rises  to  the  standard.  That  the 
action  of  the  alcohol  in  these  cases  depends  on  its  influence  on  the  nervous  system,  and  not 
on  its  chemical  action,  is  obvious  from  the  fact  that  strong  tea  acts  in  a  similar  manner,  and 
with  the  same  degree  of  rapidity  ;  three  ounces  of  strong  tea,  in  five  minutes  aft^r  being 
swallowed,  depresses  the  amount  of  carbonic  acid  progressively,  {Prout,  1813.)     Other  ex- 


NUTRITION".  813 

periments  bear  testimony  to  the  wonderful  efifect  of  alcohol  on  the  nervous  system.  Two 
miners  of  alcohol,  when  injected  into  the  stomach  of  a  rabbit,  rendered  it  immediately  insen- 
sible, just  as  if  tlie  animal  had  been  violently  struck  on  the  head.  Two  di-achms  placed  in 
the  stomach  of  a  cat,  instantly  made  it  struggle  violently  and  fall  on  its  side  perfectly  mo- 
tionless and  insensible.  It  is  remarkable,  too,  that  the  eftects  of  alcohol,  and  of  injuries, 
more  particularly  concussion  of  the  brain,  so  closely  resemble  each  other,  that  the  most 
accurate  observer  cannot  often  distinguish  them,  except  from  the  history  of  the  case,  (Sir 
B.  C.  Brodie.)  When  alcohol  is  introduced  in  excess  into  the  system^  the  arterial  blood 
appears  to  retain  the  venous  condition,  and  thus  asphyxia  may  be  produced,  (JJouchardal.) 
Alcohol,  it  is  affirmed,  has  been  detected  in  small  proportion  in  the  air  exhaled  from  the 
lungs,  and  also  in  the  blood  of  drunkards,  while  a  considerable  portion  of  acetic  acid,  one 
of  the  products  of  its  combustion,  has  been  observed  in  the  blood  after  the  use  of  this  fluid, 
(ib.)  Tiiese  views,  therefore,  tend  to  the  conclusion  that  alcohol,  in  all  its  forms,  produces 
an  alteration  in  the  usual  phenomena  consequent  upon  digestion  ;  that  this  influence  is  anal- 
ogous to  that  of  tliose  causes  which  produce  depression  of  the  nervous  centres,  and  there- 
fore its  employment  by  preference  as  a  heat-supplying  agent  to  the  animal  system  in  cases 
of  health,  is  a  procedure  involved  in  very  great  doubt.  The  argument  in  favor  of  the 
calorifiant  nature  of  alcohol  is,  that  as  it  disappears  in  the  system  it  acts  as  an  element  of 
respiration,  and  although  its  constituents  do  not  possess  by  themselves  the  property  of  com- 
bining with  oxygen  at  the  temperature  of  the  body,  and  forming  carbonic  acid  and  water, 
yet  it  acquires,  by  contact  with  bodies  susceptible  of  this  combination,  this  property  in  a 
higher  degree  than  fat,  &c.,  {TAchiy.)  If,  then,  alcohol  be  thus  capable  of  conversion  into 
carbonic  acid  and  water  with  facility,  how  are  we  to  explain  the  fact  that  alcohol  diminishes 
the  amount  of  carbonic  acid  in  the  expired  air  ?  The  answer  has  been,  that  as  alcohol  con- 
tains a  large  amount  of  hydrogen,  which,  by  union  with  the  oxygen  of  the  air,  passes  off 
from  the  lungs  in  the  form  of  vapor  of  water,  the  diminution  of  carbonic  acid  is  a  neces- 
sary result  of  the  use  of  this  stimulant.  But  there  is  a  remarkable  fact  which  appears  to 
throw  doubt  on  this  view,  viz.,  that  in  addition  to  the  analogous  and  instantaneous  action 
of  tea,  as  long  as  the  effects  of  alcohol  are  perceptible  to  the  feelings  of  the  individual  who 
has  swallowed  it,  the  quantity  of  -carbonic  acid  is  below  the  standard.  The  effects  of  drink- 
ing go  off  with  frequent  yawnings,  and  with  a  sensation  as  if  awakening  from  a  sleep. 
Under  these  circum.stances  the  quantity  is  generally  much  above  the  standard,  and  hence  it 
would  seem  that  the  system  is  freeing  itself  from  the  retained  carbon,  [Prout.)  The  phe- 
nomena of  yawning,  sighing,  &c.,  appear  to  have  evidently  the  effect  of  throwing  off  a 
quantity  of  carbonic  acid  retained  in  excess  in  the  system,  since  sleep  and  depressing  pas- 
sions seem  to  operate  by  diminishing  the  amount  of  carbonic  acid.  There  may  be  various 
reasons,  too,  for  inferring  that  alcohol  is  not  thrown  off  in  the  form  of  colorless,  odorless, 
gases  by  tlie  lungs.  The  offensive  ethereal  smell  retained  in  the  breath  of  the  drunkard  for 
many  hours  after  the  introduction  into  the  stomach  of  the  cause  of  his  inebriation,  seems 
to  favor  the  view  that  other  products  besides  carbonic  acid  and  the  vapor  of  water  result 
from  the  use  of  alcohol.  That  alcoliol  does  not  occupy  a  very  high  position  as  a  calorifiant 
agent,  is  evident  from  its  comparative  operation  in  heating  the  body  when  cooled  and  de- 
pressed by  external  cold. 

Hot  fluids  are  familiarly  known  to  all  to  be  much  more  efficient  in  raising  the  heat  of 
the  body  than  raw  spirits  or  strong  fcrme7ited  fluids,  whicli  have  a  depressing  action  unless 
combined  with  hot  fluids.  The  influence  of  the  use  of  spirits  has  been  tested  in  tlie  army, 
and  it  has  been  found  in  India,  that  when  a  regiment  consumed  from  10,000  to  14,000  gal- 
lons, the  mean  annual  mortality  was  TO,  and  when  the  amount  was  reduced  to  '2,00ii  to 
3,000,  t!ie  mortality  fell  to  21,  out  of  the  same  strength.  An  interesting  experiment  has 
been  in  operation  during  the  last  20  years  in  the  United  Kingdom  Provident  Institution. 
During  that  i)eriod  this  society  has  insured  a  distinct  section  of  abstainers  who  number 
above  5,000,  and  it  has  likewise  a  more  numerous  section  of  the  general  public.  During 
the  first  6  j'ears,  out  of  2,060  members,  only  18  died,  equivalent  to  a  loss  of  '9  per  cent., 
while  the  office  of  the  Society  of  Friends,  who  are  distinguished  for  their  care  of  health, 
lost  in  the  con-esponding  period  of  their  history  3 '3  per  cent.  The  most  recent  report  from 
this  institution,  after  1.5  years'  existence,  gives  a  return  of  19  per  cent,  of  profits  in  favor 
of  the  abstainers,  over  the  section  of  non-abstainers ;  although  that  division  likewise  con- 
tains many  individuals  of  the  latter  class. 

Influence  of  Tea  and  Coffee  in  Nutrition. — The  experiments  already  referred  to  indicate 
that  tea  delays  the  regular  changes  of  the  body  of  animals,  since  the  carbonic  acid  exhaled 
from  the  lungs  declines  in  quantity  under  the  influence  of  tea,  {Front,  \^,\'^.)  Coffee,  from 
its  containing  the  same  principle,  might  be  inferred  to  be  possessed  of  a  similar  action,  and 
this  has  been  found  to  be  the  case  ;  but  it  has  been  found,  in  addition,  that  a  decoction  of 
coffee  communicates  greater  activity  to  the  circulation  and  nervous  system.  The  delay 
which  it  effects  in  the  metamorphosis  of  the  tissues  appears  to  he  occasioned  l)y  the  cmpy- 
reumatic  oil  of  the  berry,  which  likewise  produces  increased  action  of  the  sweat  pores,  of 
the  kidneys,  and  an  accelerated  motion  of  the  intestinal  canal ;  while  the  effects  of  calfcin 


814  OIL  OF  VITRIOL. 

in  excess  are  increased  activity  of  the  heart,  headache,  delirium,  &c.,  {Lehmaixn^  1853.) 
Coffee  and  tea,  as  usually  employed,  appear  therefore  to  act  as  stimulants  and  as  agents  Ijy 
which  the  conversion  of  the  solids  of  the  body  into  soluble  and  gaseous  products  is  consid- 
erably delayed.  Their  influence  is  analogous  to  that  of  alcoholic  fluids  when  these  are  taken 
in  moderate  quantities,  although  there  is  no  evidence  that  they  are  capable  of  producing 
organic  disease,  such  as  inevitably  attends  the  consumption  of  increased  doses  of  alcoholic 
fluids.  The  Turcomans  employ  tea  in  their  wanderings  as  an  article  of  nutriment,  and  have 
discovered,  by  long  experience,  what  has  been  confirmed  by  chemical  research,  that  the 
leaves  of  tea  contain  a  large  amount  of  nitrogenous  matter,  which  is  not,  however,  dissolved 
in  the  usual  process  of  infusion.  One  ounce  of  tea-leaves  and  an  equal  weight  of  carbonate 
of  soda  are  boiled  by  the  Turcomans  in  a  quai-t  of  water  for  an  hour.  The  licjuor  is  then 
strained  and  mixed  with  ten  quarts  of  boiling  water,  in  which  an  ounce  and  a  half  of  com- 
mon salt  have  been  previously  dissolved.  The  whole  is  then  put  into  a  narrow  cylindrical 
churn  along  with  butter,  and  well  stirred  with  a  churning-stick  till  it  becomes  a  smooth, 
oily,  and  brown  liquid,  of  the  color  and  consistence  of  cliocolate,  in  which  form  it  is  trans- 
ferred into  a  teapot,  {Moorcroft.)  The  soda  has  the  effect  of  taking  up  the  cassein  or  curd, 
a  most  nutritive  nitrogenous  compound,  and  which  is  present  in  large  ((uantity. 

Influence  of  Tobacco  and  Opium  on  Nutrition. — It  has  been  observed  in  fiivor  of  the 
practice  of  smoking  tobacco,  that  even  the  most  primitive  tribes  indulge  in  this  practice. 
If  it  were  a  correct  observation,  the  practice  may  be  pronounced  to  be  a  savage  one,  and  to 
be  connected  with  the  conditions  of  savage  life.  The  North  American  Indians  all  smoke, 
but  when  uncontaminated  by  intermixture  with  the  whites,  tobacco  is  unknown  to  them. 
The  material  which  they  employ  is  the  prepared  bark  of  a  species  of  willow.  The  presence 
of  such  products  of  combustion  in  the  system  appear  like  tea  and  coffee,  which  have  also 
been  discovered  in  primitive  nations  to  delay  the  degradation  of  the  tissues  and  husband  the 
food.  The  American  Indians,  who  live  entirely  upon  animal  food,  and  who  have  impressed 
on  them  a  restless  and  wandering  existence,  from  the  nature  of  their  food — from  the  diffi- 
culty experienced  in  obtaining  animal  heat — from  the  metamorphosis  of  the  nitrogenous 
tissues — use  the  smoke  of  vegetable  matter  to  make  their  food  last  longer.  Tobacco  and 
opium  when  smoked  appear  to  have  a  similar  action,  but  they  likewise  influence  the  nervous 
system  and  occasion  a  stimulating  influence,  which  is  apparent  in  the  vivacity  of  the  eye, 
particularly  with  opium  as  it  is  smoked  in  China.  The  practice  of  opium-eating,  as  in  use 
among  the  Turks  and  the  islands  of  the  Indian  Ocean,  is  totally  distinct  in  its  physiological 
results  ;  a  wild  inebriety  being  often  produced,  which,  if  persisted  in,  conducts  to  a  lament- 
able end.  In  a  case  which  occurred  to  us^  the  liver  was  entirely  destroyed  by  fatty  degen- 
eration.—R.  D,  T. 

o 

OIL  OF  VITRIOL  is  the  old  name  of  concentrated  ScLPHrRic  Acid. 

OILS.  Clievreul  considers  all  the  oils  to  be  composed  of  two,  and  sometimes  three  dif- 
ferent species,  viz.,  stearine,  margarine,  and  oleine  ;  the  consistence  of  the  oil  or  fat  vary- 
ing as  either  of  these  predominates.  These  bodies  are  all  compounds  of  r/hicerine,  with  a 
fatty  acid.  At  all  ordinary  tempeniturcs  oleine  is  liquid  ;  margarine  is  solid,  and  melts  at 
11(3'  F.  Stearine  is  still  more  solid,  and  melts  at  about  130'  F.  The  two  latter  may  be 
prepared  from  pure  mutton  fat,  by  melting  it  in  a  glass  flask,  and  then  shaking  it  with  sev- 
eral times  its  weight  of  ether ;  when  allowed  to  cool,  the  stearine  crystallizes  out,  leaving 
the  margarine  and  oleine  in  solution.  The  soft  mass  of  stearine  may  be  strongly  pressed  in 
a  cloth,  and  further  purified  by  recrystallization  from  ether.  It  forms  a  white  friable  mass, 
iiisolutile  in  water,  and  nearly  so  in  cold  alcohol ;  but  boiling  spirit  takes  up  a  small  quan- 
tity.    It  is  freely  soluble  in  boiling  ether;  but,  as  it  cools,  nearly  all  crystallizes  out. 

Margarine  may  be  prepared  from  the  ethereal  mother-liquor,  from  which  the  stearine  has 
separated,  by  evaporating  it  to  dryness;  the  soft  mixture  of  margarine  and  oleine  is  then 
pressed  between  folds  of  blotting-paper ;  the  residue  again  dissolved  in  ether,  from  which 
the  margarine  may  now  be  obtained  tolerably  pure.  It  very  much  resembles  stearine,  but, 
as  above-mentioned,  has  a  lower  melting  point. 

It  is  rather  doubtful  if  oleine  has  ever  been  prepared  in  a  perfectly  pure  state,  the  sepa- 
rntion  of  the  last  particles  of  margarine  being  very  diflicult.  It  may  be  obtained  by  sub- 
jecting olive  oil  to  a  freezing  mixture,  when  the  margarine  will  nearly  all  separate,  and  the 
.supernatant  fluid  oil  may  be  taken  as  oleine. 

Oleine  may  also  be  procured  by  digesting  the  oils  with  a  quantity  of  caustic  soda,  equal 
to  one-half  of  what  is  requisite  to  saponify  the  whole ;  the  stearine  and  margarine  are  first 
transformed  into  soap,  then  a  portion  of  the  oleine  undergoes  the  same  change,  l)ut  a  great 
part  of  it  remains  in  a  nearly  pure  state.  This  process  succeeds  only  with  recently-expressed 
or  very  fresh  oils. 

The  fat  oils  are  completely  insoluble  in  water.  "When  agitated  with  it,  the  mixture  be- 
comes tuibi'i,  l);it  if  it  be  allowed  to  settle  the  oil  collects  by  itself  upon  the  surface.     This 


OILS.  815 

method  of  washing  is  often  employed  to  purify  oils.  Oils  arc  little  soluble  in  alcohol,  ex- 
cept at  high  temperatures.  Castor  oil  is  the  only  one  which  dissolves  in  cold  alcoliol. 
Ether,  however,  is  an  cxccUcut  solvent  of  oils,  and  is  tlierelore  employed  to  extract  them 
from  otlier  bodies  in  analysis ;  after  which  it  is  withdrawn  by  distillation. 

Fat  oils  may  be  exposed  to  a  considerably  high  temperature,  without  undergoing  much 
alteration  ;  but  when  they  are  raised  to  nearly  their  boiling  point,  they  begin  to  be  decom- 
posed. Tlie  vapors  that  then  rise  are  not  the  oil  itself,  but  certain  products  generated  in  it 
by  the  heat.  These  changes  begin  somewhere  under  600"  of  Fahr.,  and  require  for  their 
continuance  temperatures  always  increasing. 

The  products  in  this  case  arc  the  same  as  we  obtain  when  we  distil  separately  the  differ- 
ent constituents,  (stearine,  margarine,  &c.,)  that  is  to  .say,  a  little  water  and  carbonic  acid, 
some  gaseous  and  liquid  hydrocarbons,  some  solid  fatty  acids,  (particularly  margaric  acid 
and  some  sebacic  acid,  provided  by  the  decomposition  of  the  oleine,)  small  quantities  of  the 
odoriferous  acids,  (acetic,  butyric,  &c.,)  and  some  acroleine.  The  acrid  and  irritant  odor 
which  this  last  substance  gives  out  especially  characterizes  the  decomposition  of  fatty  bodies 
by  heat.  It  is  produced  from  the  glycerine  only.  If,  instead  of  raising  the  heat  gradually, 
we  submit  the  fats  or  oils  directly  to  a  red  heat,  as  by  passing  them  through  a  red-hot  tube, 
they  are  decomposed  completely,  and  are  almost  entirely  transformed  into  gaseous  carburet- 
ted  hydrogens,  the  mixture  of  which  serves  for  illuminating  purposes,  and  yields  a  far  bet- 
ter light  than  ordinary  coal  gas.  In  places  where  the  seed  and  fish  oils  can  be  procured  at 
a  low  price,  these  substances  might  be  employed  with  great  advantage  for  this  purpose. 

Action  of  Alkalies  on  the  Oih. — When  the  fats  or  oils  are  boiled  with  potash  or  soda, 
they  are  decomposed  into  glycerine  and  the  fatty  acids,  with  assimilation  of  water  by  both 
the  gh'cerine  and  the  fatty  acids.  Thus  oleine  yields  glycerine  and  oleic  acid,  margarine, 
glycerine  and  margaric  acid,  and  stearine,  gljxerine  and  stearic  acid.  The  glycerine  dis- 
solves in  the  water  and  the  fatty  acids  unite  with  the  alkalies,  forming  soaps,  (which  see.) 
The  action  of  ammonia  on  the  oils  is  much  less  energetic  ;  it,  however,  .readily  mixes  with 
them,  forming  a  milky  emulsion,  called  volatile  liniment,  used  as  a  rubefiicient  in  medicine. 
Upon  mixing  water  with  this,  or  by  neutralizing  the  ammonia  by  an  acid,  or  even  by  mere 
exposure  to  the  air,  the  ammonia  is  removed  and  the  oil  again  collects.  By  the  prolonged 
action  of  ammonia,  however,  on  the  oils,  true  ammoniacal  soaps  are  formed,  and  at  the  same 
time  a  peculiar  body  is  formed,  called  by  its  discoverer  (Boullay)  marciaramid.  It  corre- 
sponds exactly  with  the  ordinary  amides,  its  composition  is  (C^^H'^XO^)  =  NH\C^''H^^O'^) 
or  margarate  of  ammonia  minus  2  equivalents  of  water. 

NH^0,C5'H='0'  —  2H0  =  NIP  (C'^H^W) 


Margarate  of  ammonia.  Margaramid. 

It  is  obtained  by  boiling  the  ammoniacal  soap  with  water,  when  the  margaramid  swims 
on  the  top,  and  when  allowed  to  cool  solidifies.  It  is  purified  by  solution  in  boiling  alco- 
hol, which  deposits  it  again  on  cooling  in  the  crystalline  state.  It  is  a  white,  perfectly  neu- 
tral solid,  unalterable  in  the  air,  insoluble  in  w;iter,  very  soluble  in  alcohol  and  ether,  espe- 
cially by  the  aid  of  heat.  It  fuses  at  about  140°  Fahr.,  and  burns  with  a  smoky  flame.  It 
is  decomposed  when  boiled  with  potash  or  soda,  forming  true  soaps,  with  the  liberation  of 
ammonia,  and  also  by  acids  of  a  certain  degree  of  concentration. 

The  alkaline  earths  and  some  metallic  oxides  unite  with  the  fatty  acids,  forming  insol- 
uble soaps,  which  in  the  case  of  lead  is  called  a  plaster. 

After  glycerine  and  the  fatty  acids  have  once  been  separated,  they  do  not  readily  again 
unite  ;  but  Berthelot  has  succeeded  in  effecting  this,  by  enclosing  them  lor  a  consideralile 
tim(;  in  a  sealed  tube,  and  subjecting  them  to  a  more  or  less  elevated  temperature,  when  the 
true  oils  are  again  producccl. 

Action  of  Acidi  upon  (he  Oih.. — Sulphuric  acid,  (concentrated,)  when  added  to  tlie 
oils,  unites  with  them  energetically,  the  mixture  becomes  heated,  ancl,  unless  cooled,  chars 
with  the  liberation  of  sulphurous  acid.  When  the  mixture  is  cooled,  the  fats  and  oils  un- 
dergo a  similar  change  to  that  which  the  alkalies  effect.  There  is  formed  some  sulplio- 
glyceric  acid,  as  well  as  combinations  of  margaric  and  oleic  acids  with  sulphuric  acid  ;  tlicso 
latter  are  again  decomposed  when  mixed  with  water,  liberating  the  fatty  acids. 

Nitric  arid  (concentrated)  attacks  the  fatty  l)odies  very  rapidly,  sitmetimes  causing  igni- 
tion. Dilute  nitric  acid  acts  less  powerfully,  forming  the  same  compounds  which  wc  obtain 
by  acting  on  the  several  constituents  of  the  oils  separately. 

Iliiprinitric  acid,  or  nitrous  acid,  converts  the;  oW'ine  of  the  non-drying  oils  into  a  solid 
fat,  elnidlne. 

Chlorine  and  bromine  act  on  the  fatty  oils,  produi'ing  hydrochloric  and  hydrobromic 
acids,  and  some  substitution  compounds  containing  chlorine  or  bromine. 

When  moist  chlorine  gas  is  passed  into  the  oils,  the  tt'mi>erature  rises,  but  it  does  not 
cause  explosion.  Bromine,  on  the  contrary,  acts  with  violence.  The  chlorine  and  l>romine 
pnxhicts  thus  obtaitied  arc  generally  of  a  yellow  color,  without  tiustc  or  smell.  They  are 
heavier  than  water,  and  possess  a  greater  consistence  than  the  pure  oils.  Exposed  to  tlie  air 
when  slightly  heated,  they  become  considerably  harder. 


816 


OILS. 


Iodine  also  attacks  the  oils,  forming  substitution  compounds. 

The  fatty  oils  are  divided  into  two  classes,  drying  and  non-drying  oils,  which  are  charac- 
terized by  their  dirterent  deportments  when  exposed  to  the  atmosphere.  In  close  vessels, 
oils  may  be  preserved  unaltered  for  a  very  long  time,  but  with  contact  of  the  atmosphere 
they  undergo  progressive  changes.  Certain  oils  thicken  and  eventually  dry  into  a  trans- 
parent, yellowish,  flexible  substance,  which  forms  a  skin  upon  the  surface  of  the  oil  and 
retards  its  further  alteration.  Such  oils  are  said  to  be  drying,  or  siccative^  and  are  on  this 
account  used  in  the  preparation  of  varnishes  and  painters'  colors.  Other  oils  do  not  dry  up, 
though  they  become  thick,  less  combustible,  and  assume  an  offensive  smell.  These  are  the 
non-dryiiig  oils.  In  this  state  they  are  called  rancid,  and  exhibit  an  acid  reaction,  and  irri- 
tate the  fauces  when  swallowed,  in  consequence  of  the  presence  of  a  peculiar  acid,  which 
may  be  removed  in  a  great  measure  by  boiling  the  oil  along  with  water  and  a  little  common 
magnesia  for  a  quarter  of  an  hour,  or  till  it  has  lost  the  property  of  reddening  litmus. 
While  oils  undergo  the  above  changes,  they  absorb  a  quantity  of  oxygen  equal  to  several 
times  their  volume.  Saussure  found  that  a  layer  of  nut  oil,  one  quarter  of  an  inch  thick, 
enclosed  along  with  oxygen  gas  over  the  surface  of  quicksilver  in  the  shade,  absorbed  only 
three  times  its  bulk  of  that  gas  in  the  course  of  eight  mouths ;  but  wlien  exposed  to  the 
sun  in  August,  it  absorbed  GO  volumes  additional  in  the  course  of  ten  days.  This  absorp- 
tion of  oxygen  diminished  progressively,  and  stopped  altogether  at  the  end  of  three  months, 
when  it  had  amounted  to  115  times  the  bulk  of  the  oil.  Ko  water  was  generated,  but  21'9 
volumes  of  carbonic  acid  were  disengaged,  while  the  oil  was  transformed  in  an  anomalous 
manner  into  a  gelatinous  mass,  which  did  not  stain  paper.  To  a  like  absorption  we  may 
ascribe  the  elevation  of  temperature  which  happens  when  wool  or  hemp,  besmeared  with 
olive  or  rapeseed  oil,  is  left  in  a  heap  ;  circumstances  under  which  it  has  frequently  taken 
fire,  and  caused  the  destruction  of  both  cloth-mills  and  dockyards. 

In  illustration  of  these  accidents,  if  paper,  linen,  tow,  wool,  cotton  mats,  straw,  wood 
shavings,  moss,  or  soot,  be  imbued  slightly  with  linseed  or  hempseed  oil,  especially  when 
wrapped  or  piled  in  a  heap,  and  placed  in  contact  with  the  sun  and  air,  they  very  soon  spon- 
taneously become  hot,  emit  smoke,  and  finally  burst  into  flames.  If  linseed  oil  and  ground 
manganese  be  triturated  together,  the  soft  lump  so  formed  will  speedily  become  firm,  and 
ere  long  take  fire. 

Although  most  of  the  fixed  oils  and  fats  are  mixtures  of  two  or  more  of  the  substances 
oleine,  margarine  and  stearine,  yet  there  appeai-s  to  be  different  modifications  of  these  sub- 
stances in  drying  and  non-drying  oils ;  for  instance,  it  is  only  the  oleine  of  the  non-drying 
oils  that  solidifies  when  treated  with  nitrous  acid  or  nitrate  of  mercury  ;  and  again  the  dif- 
ference is  shown  in  the  fact  of  some  oils  drying  completely,  while  others  only  thicken  and 
become  rancid. 

A  patent  was  taken  out  in  May,  1849,  by  Messrs.  Bessemer  &  Heywood,  for  a  machine 
to  be  used  for  expressing  oils  from  seeds.     Fig.  467  is  a  drawing  of  it.     The  bedplate  of 

46*7 


framing,  <?,  which  should  be  cast  in  one  piece,  forms,  at  a',  a  cistern  for  the  reception  of 
the  oily  matters  which  fall  therein  as  they  are  expressed.  At  the  opposite  end  of  the  bed- 
plate tliere  are  formed  projections,  a^,  in  which  brasses,  b,  are  fitted,  and  with  the  caps,  c, 
form  bearings  for  the  crank  shaft,  d,  to  turn  in.  There  are  also  two  other  projections,  a', 
d'\  cast  on  to  the  Ijcdplate,  and  are  provided  with  caps,  e,  in  a  similar  manner  to  the  caps 
of  plumnicr  blocks.  These  caps  are  for  the  purpose  of  retaining  firmly  in  its  place  the 
pressing  cylinder,  /,  which  should  bejiiade  of  tough  gun-metal,  and  of  such  thickness  as  to 
be  capable  of  withstanding  a  considerable  amount  of  internal  pressure.  Within  the  cylin- 
der, f,  is  fitted  a  lining,  which  consists  of  a  gun-metal  tube,  n,  having  a  spiral  groove,  r, 
cut  on  the  outside  of  it,  and  presenting  the  appearance  of  an  ordinary  squai'e-threaded 
screw.  At  very  short  intervals  all  along  the  spiral  groove  there  are  conical  holes,  s,  drilled 
through  the  tube,  n,  and  communicating  with  the  interior  of  it.  At  n'  the  inside  of  the 
tube  is  enlarged,  and  is  provided  with  a  steel  collar,  t.  The  opposite  end  of  the  tube  at  »t' 
is  reduced  in  diameter,  and  is  provided  externally  with  a  steel  collar,  u.     A  plain  cylindrical 


OILS. 


817 


bag  T,  with  open  ends,  formed  of  fustian,  hair-cloth,  or  similarly  pervious  material,  is  made 
of  such  a  diameter  as  will  fit  closel}'  to  the  inside  of  the  tube  n  ;  and  within  this  bag  is 
placed  a  cylinder,  w,  of  wire  gauze  or  finely  perforated  metal.  The  steel  collar  t  is  forced 
into  the  end  of  the  wire  gauze,  by  which  it  becomes  driven  into  the  recess  formed  at  n', 
and  is  securely  held  there  by  the  pressure  of  the  collar  t.  The  bag  v  and  wire  gauze  w  are 
then  tightly  stretched  over  the  end  u"^  of  the  tube,  and  the  collar  u  driven  tightly  on,  by 
which  means  the  bag  and  wire  gauze  are  securely  held  in  their  places.  The  lining  tube  n 
is  then  put  into  the  pressing  cylinder  as  far  as  the  shoulder  rj.  A  tubular  piece  h  is  next 
put  in  and  brought  into  contact  with  the  collar  u^  and  then  the  gland  i  is  screwed  home, 
whereby  the  lining  n  is  firmly  retained  within  the  pressing  cylinder.  The  end  of  the  press- 
ing cylinder  is  contracted  at  /',  and  forms  a  shoulder  for  the  abutment  of  the  collar  J,  the 
diameter  of  the  aperture  in  which  regulates  the  pressure  to  which  the  matters  under  opera- 
tion are  subjected.  Within  the  tube  n  there  is  fitted  a  solid  plunger  A-,  which  receives  mo- 
tion from  the  crank  d  by  means  of  the  connecting  rod  /,  the  parallel  motion  being  obtained 
by  the  wheels  ?«,  on  the  cross-head  o,  traversing  on  the  side  of  the  bedplate  at  a*,  a:  is  a 
hopper,  bolted  to  a  flange/^  on  the  pressing  cylinder,  and  communicating  therewith.  There 
is  also  an  opening  in  the  tube  n  at  n\  corresponding  with  the  opening  into  the  hopper,  so 
that  any  materials  placed  into  the  hopper  may  fall  into  the  tube  ?i,  when  the  plunger  k  is 
withdrawn  from  beneath  the  opening.  At  that  part  of  the  pressing  cylinder  which  is  occu- 
pied by  the  "  lining,"  there  are  drilled  numerous  small  holes,  /^,  which  communicate  at 
various  points  with  the  spiral  groove  in  the  tube  n.  On  the  outside  of  the  pressing  cylin- 
der there  are  formed  two  collars,  /*,/*,  which  abut  against  the  projecting  pieces  a^  and 
caps  e,  and  cause  the  pressing  cylinder  to  be  retained  firmly  in  its  place.  When  steam- 
power  is  to  be  employed  to  give  motion  to  the  oil  press,  it  is  preferable  to  have  the  crank 
which  is  actuated  by  the  steam  piston  formed  on  the  end  d',  on  the  crank  shaft  of  the  oil 
press,  and  placed  at  such  an  angle  to  the  crank  d,  that  when  the  crank  d  is  pushing  the 
plunger  k  to  the  end  of  its  stroke,  the  steam  piston  will  be  at  the  half  stroke,  whereby  the 
motive  power  applied  will  be  the  greatest  at  the  time  that  the  press  offers  the  most  resist- 
ance, and  the  steam  piston  also,  when  passing  its  dead  points,  will  have  to  overcome  the 
friction  of  the  machinery  only,  as  the  plunger  k  will  be  in  the  middle  of  its  back  stroke. 
When  any  other  motive-power  is  applied  to  turn  the  crank  d,  it  will  be  necessary  to  put  a 
fly-wheel  on  the  shaft  d\  as  also  such  cog-wheels  as  will  be  necessary  to  connect  it  with  the 
first  mover.  When  this  apparatus  is  to  be  employed  in  expressing  linseed  oil,  the  seed, 
after  having  been  ground  and  treated  in  the  way  now  commonly  practiced,  is  put  into  the 
hopper,  and  motion  being  transmitted  to  the  crank  in  the  manner  before  described,  the 
plunger  k  will  commence  a  reciprocating  movement  in  the  tube  u  of  the  pressing  cylinder. 
Each  time  that  it  recedes  in  the  direction  of  the  crank  it  will  move  from  under  the  opening 
in  the  hopper,  and  allow  a  portion  of  the  seed  to  fall  into  the  tube,  while  the  reverse  mo- 
tion of  the  plunger  will  drive  it  towards  the  open  end  of  the  cylinder,  its  passage  being 
much  retarded  by  the  friction  against  the  sides  of  the  tube  lining,  but  chiefly  by  the  con- 
traction of.  the  escape  aperture  through  the  collar  J,  which  will  produce  a  considerable 
amount  of  resistance,  and  consequently  the  plunger  will  have  to  exert  an  amount  of  pres- 
sure upon  the  seed  in  proportion  as  the  escape  aperture  is  made  larger  or  smaller.  The  col- 
lar j  is  made  movable,  and  by  withdrawing  the  plunger  entirely  from  the  tube,  it  can  be 
exchanged  at  any  time  for  another  having  a  larger  or  smaller  opening.  The  lining  may  at 
any  time  be  removed  from  the  cylinder,  and  the  worn  parts  removed  when  found  requisite. 
The  action  of  the  plunger  is  somewhat  like  that  of  the  plunger  of  a  hydraulic  press  pump, 
the  seeds  being  pumped  in  at  one  end  of  the  pressing  cylinder,  and  allowed  to  escape  at  the 
other,  while  the  whole  of  the  interior  of  the  pressing  cylinder  that  contains  seed  is  lined 
with  hair-cloth  or  other  suitable  pervious  material,  and,  that  it  may  be  protected  from  injury, 
is  covered  with  wire  gauze  or  finely  perforated  metal.  The  bag  is  thus  completely  defended 
from  within,  while  it  is  supported  at  every  part  by  the  tube  ?i  on  the  outside,  and  is  thus 
subjected  to  a  very  little  wear  and  to  no  risk  of  bursting.  Tiie  expressed  oil,  pa.ssing  through 
the  wire  gauze  and  bag,  finds  its  way  through  the  perforation  s  into  the  spiral  channel  r, 
and  from  thence  it  finds  ready  egress  by  the  perforations  f^  in  the  pressing  cylinder,  and  as 
it  falls  is  received  by  the  cistern  a',  from  which  it  can  be  drawn  by  the  pipe  ?/. 

Two  or  more  presses  may  be  used  side  by  side,  actuated  either  by  one  crank  throw  or 
by  separate  throws  upon  one  shaft,  placed  with  reference  to  each  other  in  such  manner  as 
greatly  to  equalize  the  amount  of  resistance  throughout  the  revolution  of  the  crank  shaft. 
Although  the  one  here  described  is  a  cylindrical  pressing  plunger,  an  angular  section  may 
he  given  to  the  pressing  vessel  and  plunger,  and  may  of  course  be  used  to  cx])ress  oils  from 
any  seeds  containing  them.  In  the  drawing,  no  method  is  shown  for  heating  the  .seed  cake 
to  be  subjected  to  pressure  therein,  but  as  it  is  known  to  be  desirable  to  heat  some  matters 
from  which  oil  is  to  be  expressed,  the  following  method  is  described  : — When  heat  is  to  be 
applied  during  the  process  of  pressing,  it  is  desirable  to  make  the  pressing  cylinder  of  some- 
what larger  diameter,  and  of  greater  length,  and  to  divide  the  cistern  a'  into  two  separate 
compartments,  over  both  of  which  the  pressing  cyHuder  is  to  extend  ;  a  strong  wrought- 
VoL.  III.— 52 


818 


OILS. 


468 


iron  tube  is  to  enter  the  open  end  of  the  pressing  cylinder,  and  to  extend  about  half-way  to 
the  hopper,  where  it  terminates  in  a  solid  pointed  end  ;  this  tube  is  to  occupy  the  centre  of 
the  pressing  cylinder,  and  will  consequently  leave  an  annular  space  around  it,  which  will  be 
occupied  by  the  seed,  meal,  or  other  matters  under  operation.  Steam  is  let  into  this  iron 
tube,  and  its  temperature  thereby  raised  to  any  desired  point.  The  end  of  the  tube  which 
extends  beyond  tlic  pressing  cylinder  is  to  be  securely  attached  to  a  bracket  projecting  from 
the  bedplate,  so  that  it  may  be  firmly  held  in  its  position,  notwithstanding  the  force  exerted 
against  the  pointed  end  of  it.  Tiie  effect  of  this  arrangement  will  be,  that,  as  the  seed, 
meal,  &c.,  fall  into  the  pressing  cylinder  and  are  pushed  forward  by  the  plunger,  they  will 
give  out  a  portion  of  their  oil  in  that  state  known  as  cold  drawn,  which  will  fall  into  the  first 
compartment  of  the  cistern  «'.  The  further  progress  of  the  meal  along  the  pressing  cylin- 
der will  bring  it  in  contact  with  the  pointed  end  of  the  heating  tube  •,  here  it  will  have  to 
divide  itself,  and  pass  along  the  annular  space  between  the  heating  tube  and  the  lining,  and 
being  thus  spread  into  a  thin  cylindrical  layer  around  the  tube,  it  will  readily  absorb  heat 
therefrom,  when  a  second  portion  of  oil  will  be  given  out  and  received  by  the  second  com- 
partment of  the  cistern  ;  and  thus  will  the  operations  of  cold  and  hot  pressing  be  carried 
on  simultaneously. 

Bessemer  &  Heywood's  patent  also  mentions  another  machine  for  the  expression  of  oils 
from  the  seeds,  &c.,  by  pressure  in  connection  with  water,  or  water  rendered  slightly  alka- 
line.    A  sectional  drawing  of  it  is  represented  in  fg.  468.     a  is  a  cast-iron  cistern,  having 

semicircular  ends,  and  open  on  the  upper  side.  At 
one  end  of  it  is  fixed  a  cylindrical  vessel,  b,  with 
hemispherical  ends.  This  vessel  is  of  considerable 
strength,  and  should  be  capable  of  withstanding  a 
pressure  of  5,000  pounds  to  the  square  inch.  It  is 
held  in  an  upright  position  by  a  flange,  c,  formed  upon 
it,  and  extending  around  one-half  of  its  circumfer- 
ence. Tliis  flange  rests  upon  a  similar  one  formed 
around  the  upper  side  of  the  cistern  a,  and  is  bolted 
thereto.  At  the  upper  part  of  the  vessel  b  is  formed 
a  sort  of  basin,  b',  the  edge  of  which  supports  an  arch- 
shaped  piece  of  iron,  d.  At  the  centre  of  the  basin 
there  is  an  opening  into  the  vessel,  and  a  hydraulic 
cup-leather,  e,  is  secured  within  the  opening  by  means 
of  the  collar  g.  In  the  bottom  of  the  vessel  b  there 
is  also  an  opening,  into  which  is  fitted  a  cup-leather, 
H,  secured  in  its  place  by  the  ring  j,  which  is  firmly 
bolted  to  the  vessel  b.  A  strong  wrought-iron  rod,  k, 
extends  from  the  top  of  the  arch  d,  down  through 
the  vessel  b,  having  two  enlargements  or  bosses,  k', 
K^,  formed  upon  it,  -which  are  fitted  to  the  cup- 
leathers.  The  upper  part  of  rod  k  has  a  screw  formed 
upon  it  at  k^,  which  passes  through  the  bo.ss  n'  and 
enters  the  boss  n,  in  which  a  screw  thread  is  formed. 
The  boss  n  is  provided  with  handles,  p,  by  turning 
Tvhich  the  rod  K  may  be  raised  or  lowered  when  re- 
quired. R  is  a  pipe,  through  which  water  may  be 
injected  into  the  vessel  b  by  a  force-pump,  such  as  is 
generally  employed  to  work  hydraulic  presses,  s  is  a 
cock,  whereby  a  portion  of  the  contents  of  the  vessel 
b  may  be  run  off,  and  the  pressure  relieved  when 
necessary.  The  two  bosses,  k'  and  k^,  being  of  equal 
area,  whatever  pressure  may  be  exerted  within  the 
vessel  B,  it  does  not  tend  to  raise  or  lower  the  rod  K, 
but  such  pressure,  acting  on  the  cup-leathers,  will  keep 
the  joint  tight,  and  prevent  the  matters  under  pressure 
from  leaking  out.  After  a  certain  quantity  of  oil  or  oleaginous  matters  have  been  expressed 
from  vegetable  or  animal  substances,  the  remaining  portions  which  they  contain  are  more 
difficult  to  obtain,  and  we  therefore  treat  the  oil  in  combination  witli  the  substances  in  which 
it  is  contained  in  the  following  manner: — The  aforesaid  subst.inccs,  after  coming  from  the 
oil-press  or  mill,  are  mixed  with  as  much  warm  water,  or  water  slightly  impregnated  with 
alkaline  matter,  as  will  reduce  them  to  a  semi-fluid  state.  They  are  then  to  be  operated 
upon  in  the  apparatus  last  described.  For  this  purpose  the  handles  p  p  are  turned  round, 
and  the  boss  k'  withdrawn  from  its  opening,  while  the  boss  k",  which  is  miich  longer,  will 
still  close  the  lower  aperture.  The  semi-fluid  materials  are  then  put  into  the  basin  n',  and 
fall  from  thence  into  the  vessel  n  ;  when  it  is  fully  charged  the  rod  k  is  again  lowered  into 
the  position  shown  in  the  figure.     The  communication  with  the  hj-draulic  press  pnmp  is 


OILS. 


819 


then  made  by  means  of  a  cock  attached  to  the  pump,  from  which  the  water  flows*  through 
the  pipe  R  into  the  vessel  b,  and  thus  with  a  few  strokes  of  the  pump  the  whole  of  the  con- 
tents of  the  vessel  b  will  be  subjected  to  the  requisite  pressure.  An  interval  of  a  few  min- 
utes is  then  allowed  for  the  combination  of  the  oil  and  water,  and  tlic  cock  s  is  then  opened, 
and  a  small  portion  of  the  tiiiid  contents  of  the  vessel  allowed  to  escape  into  the  cistern.  The 
pressure  being  thus  relieved,  the  handles  p  p  are  to  be  again  turned  so  as  to  lift  the  rod  k  suffi- 
ciently high  to  withdraw  the  boss  k"  from  the  lower  opening ;  the  contents  of  the  vessel  b 
will  then  How  out  into  the  cistern  a,  and  the  boss  k.'^,  being  again  lowered  so  as  to  close  the 
lower  aperture,  the  refilling  of  tlie  vessel  may  take  place  for  another  operation.  The  pres- 
sure thus  brought  upon  the  mixture  of  oleaginous  matters  and  water  wilt  cause  the  oil  therein 
contained  to  mix  witii  the  water,  and  form  a  milky-looking  Huid,  from  which  the  oil  may  be 
afterwards  separated  from  the  water,  either  by  repose  in  large  vessels  or  by  evaporating  the 
water  therefrom  by  heat.  When  the  oil  is  to  be  used  for  soap-making,  and  some  other  pur- 
poses, this  combination  of  oil  and  water  may  be  used  withoiit  such  separation.  When  seed 
oil  is  thus  obtained,  the  mucilaginous  matters  assist  in  combining  these  fluids.  After  the 
materials  have  been  drawn  off  from  the  cistern  a,  and  passed  through  a  strainer,  the  solid 
portions  are  to  undergo  another  pressing,  in  order  to  displace  the  remaining  portion  of  their 
fluid  contents.  In  some  cases  it  will  be  found  advantageous  to  boil  up  the  milky-looking 
fluid  resulting  from  the  operation  last  described,  in  order  to  coagulate  the  albuminous  por- 
tions and  otherwise  assist  in  the  purification  of  the  oil. 

Piirijicafion  *  oils. —  As  the  oils  are  obtained  from  the  mills  they  generally  contain 
some  albuminous  and  mucilaginous  matter,  and  some  other  impurities  which  require  to  be 
removed,  in  order  to  render  the  oil  perfectly  clear  and  fit  for  burning,  &c.  Several  pro- 
cesses have  been  proposed  for  this  purpose ;  the  one  most  generally  used  is  that  known  as 
Thenard's  process. 

Although  concentrated  sulphuric  acid  acts  so  strongly  on  the  oils,  it  is  found  that,  when 
added  only  in  small  quantities,  it  attacks  principally  the  impurities  first.  Thenard's  process 
consists  in  adding  gradually  1  or  2  per  cent,  of  sulphuric  acid  to  the  oil,  previously  heated 
to  10i)°,  and  well  mixing  them  by  constant  agitation.  To  effect  thi.s,  the  process  may  be 
carried  on  in  a  t)arrel  fixed  on  an  axis  and  kept  revolving,  or  in  a  Ijarrel  which  is  itself 
immovable,  but  having  fixed  in  its  axis  a  movable  fan.  After  the  action  of  the  acid  is 
complete,  which  is  known  by  the  oil,  after  twenty-four  hours'  rest,  appearing  as  a  clear 
liquid,  holding  flocculent  matter  in  suspension,  there  is  added  to  it  a  quantity  of  water, 
heated  to  140',  equal  to  about  two-thirds  of  the  oil;  this  mixture  is  well  agitated  until  it 
acquires  a  milky  appearance.  It  is  then  allowed  to  settle,  when,  after  a  few  days,  the  clari- 
fied oil  will  rise  to  the  surface,  while  the  flocculent  will  have  fallen  to  the  bottom  of  the 
acid  liquid.  The  oil  may  then  be  diawn  off",  but  requires  to  be  filtered  to  make  it  perfectly 
clear.  The  filtration  is  always  a  difficult  matter,  and  is  conducted  in  various  ways.  It  is 
sometimes  placed  in  tubs,  in  the  bottom  of  which  there  are  conical  holes  filled  with  cotton, 
but  the  holes  become  speedily  choked  with  solid  matters.  Another  and  more  speedy 
process  is  by  the  means  of  a  displacing  funnel,  the  apertures  in  the  diaphragm  being  stopped 
with  cotton. 

Several  patents  have  been  taken  out  for  the  purification  of  oils.  Some  passing  hot  air 
through  the  oil  while  at  the  same  time  exposed  to  the  action  of  light,;  others  passing  steam 
through  the  oil. 

Cogau's  process  is  a  combination  of  the  latter  with  Thenard's.  He  operates  upon  about 
100  gallons  of  oil,  and  for  this  quantity  he  uses  about  10  pounds  of  sulplunic  acid,  which 
he  dilutes  previously  with  an  equal  bulk  of  water.  This  acid  mixture  is  added  to  the  oil, 
pi  iced  in  a  suitable  vessel,  in  three  parts,  the  oil  being  well  stirred  for  about  an  hour 
between  each  addition.  It  is  then  .stirred  for  two  or  three  hours  in  order  to  insure  a  perfect 
mixture,  and  thus  let  every  particle  of  the  oil  be  acted  on  by  the  acid.  It  then  has  assumed 
a  very  dark  color.  After  being  allowed  to  stand  for  twelve  hours,  it  is  transferred  to  a 
copper  boiler,  in  the  bottom  of  which  are  holes,  through  which  steam  is  admitted,  and, 
pa.ssing  in  a  finely  divided  state  through  the  oil,  raises  it  to  the  temperature  of  212'.  This 
steam  process  is  carried  on  for  six  or  seven  hours;  the  oil  is  then  transferred  to  a  cooler, 
having  the  shape  of  an  inverted  cone,  terminating  in  a  short  pipe,  provided  with  a  stoji-cock 
inserted  in  its  side  a  little  distance  from  the  bottom.  After  i)eiiig  allowed  to  stand  till  the 
liquids  are  sejiarated,  which  generally  takes  about  twelve  hours,  the  acid  li((uor  is  drawn 
oil' through  the  pipe  at  the  bottom,  and  t'.ie  clear  oil  by  the  stop-cock  in  tlie  side  of  the 
cooler;  all  below  this  tap  is  generally  turbid,  and  is  clarified  by  sul)sidence  or  mixed  with 
-  the  next  portion  of  oil. 

Sometimes  an  infusion  of  nut-galls  is  used  to  separate  the  impurities,  the  tannic  acid 
contained  in  which  renders  the  impurities  less  soluble;  the  infusion  is  well  mixeil  with  the 
oil  by  agitation,  and  af'tei'  separating  the  two  licpnils,  the  oil  is  depriveil  of  any  tannic  acid 
it  may  have  rctaini'd,  by  treating  it  with  acetate  of  lead,  w  sid|)hate  of  y.ine.  When  the  oil 
is  to  be  used  fur  machinery  it  nmst  be  dried  by  treatment  with  freshly  calcined  sulphate  of 
llaie,  or  carbonate  of  soda. 


820 


OILS. 


General  Remarks  on  the  Non-drying  Oils. 

Olive  oil. — Few  vegetables  have  been  so  repeatedly  noticed  and  so  enthusiastically 
described  by  the  ancient  writers  as  the  olive  tree.  It  seems  to  have  been  adopted  in  all 
ages  as  the  emblem  of  benignity  and  peace.  The  pre.ieri'cd  or  pickled  olives,  so  admired 
as  a  dessert,  are  the  green  unripe  fruit  deprived  of  part  of  their  bitterness  by  soaking  them 
in  water,  and  preserved  in  an  aromatized  solution  of  salt.  There  are  several  varieties  met 
with  in  commerce,  but  the  most  common  are  the  small  French  or  Provence  olive  and  the 
lar^e  Spanish  olive.  When  ripe  the  fruit  abounds  in  a  bland  fixed  oil.  The  processes  for 
extracting  it  have  already  been  mentioned.  Olive  oil  is  an  unctuous  fluid,  of  a  pale  yellow 
or  greenish  yellow  color.  The  best  kinds  have  scarcely  any  smell ;  a  bland  and  mild  taste. 
In  cold  weather  it  deposits  white  fatty  globules  (a  combination  of  olein  and  margarine).  It 
is  soluble  in  about  1^  times  its  weight  of  ether ;  but  is  only  very  slightly  soluble  in  alcohol. 
By  admixture  with  castor  oil,  its  solubility  in  spirit  seems  to  be  increased.  Pure  olive 
oil  has  less  tendency  to  become  rancid  than  most  other  fixed  oils,  but  the  second  qualities 
rajjidly  become  rancid,  owing  probably  to  some  foreign  matters.  It  is  not  a  drying  oil,  and 
is  less  apt  to  thicken  by  exposure  to  the  air,  and  for  this  reason  is  preferred  for  greasing 
delicate  machinery,  especially  watch  and  clock  work.  Brande  describes  a  process  for  pre- 
paring it  for  these  latter  purposes.  The  oil  is  subjected  to  cold,  when  it  principally  solidi- 
fies; the  portion,  however,  which  still  remains  liquid  is  poured  off  from  the  solid  portion. 
A  piece  of  sheet  lead,  or  some  shot,  are  then  placed  in  it,  and  it  is  e^|posed  in  a  corked 
phial  to  the  action  of  sunshine.  A  white  matter  gradually  separates,  after  which  the  oil 
becomes  clear  and  colorless,  and  is  fit  for  use.  i^ome  oil  prepared  by  this  process  kept  its 
consistence  very  well  for  four  or  five  years  while  in  a  stoppered  bottle,  but  when  exposed 
to  the  atmosphere  it  began  to  thicken,  and  did  not  answer  so  well  as  was  expected  by  the 
watch-maker,  who  tried  it  from  its  appearance  before  exposure  to  the  air. 

The  principal  object  in  the  process  appears  to  be  to  get  as  pure  oleine  as  possible,  but 
the  purer  the  oleine  the  more  likely  is  it  to  become  thick.  Accordiug  to  Kerwych,  oleine 
of  singular  beauty  may  be  obtained  by  mixing  two  parts  of  olive  oil  with  one  part  of  caustic 
soda  lye,  and  macerating  the  mixture  for  twenty-four  hours,  with  frequent  agitation.  Weak 
alcohol  must  then  be  poured  into  it,  to  dissolve  the  margarine  soap,  whereby  the  oleine,  which 
remains  unsaponificd,  is  separated,  and  floats  on  the  surface  of  the  liquid.  This  being  drawn 
off,  a  fresh  quantity  of  spirit  is  added,  till  the  separation  of  the  oleine  be  complete. 

It  has  a  slightly  yellowish  tint,  which  may  be  removed  by  digesting  with  a  little  animal 
charcoal  in  a  warm  place  for  twenty-four  hours.  By  subsequent  filtration,  the  oleine  is 
obtained  limpid  and  colorless,  and  of  such  quality  that  it  docs  not  thicken  with  the  greatest 
cold,  nor  does  it  affect  either  iron  or  copper  instruments  immersed  in  it.  Tiiere  are  four 
different  kinds  of  olive  oil  known  in  the  districts  where  it  is  prepared: — 1.  Virgin  oil; 
2.  Ordinary  o\\  {hnile  ordinaire);  3.  Oil  of  the  i7i fern al  regions  {hiiile  d'eri/er);  4.  Oil 
prepared  by  fermentation. 

1.  Virgin  oil. — In  the  district  Montpellier,  they  applied  the  term  rirgin  oil  to  that 
which  spontaneously  separates  from  the  paste  of  crushed  olives.  This  oil  is  not  met  with  in 
commerce,  being  all  used  by  the  inhabitants  of  the  district  either  as  an  emollient  remedy  or 
for  oiling  the  works  of  watches. 

In  the  district  of  Aix,  they  give  the  name  virgin  oil  to  that  which  is  first  obtained  from 
the  olives  ground  to  a  paste  in  a  mill,  and  submitted  to  a  slight  pressure  two  or  three  days 
after  collecting  the  fruit.  Thus,  there  is  no  virgin  oil  brought  from  Montpellier,  but  a  good 
deal  of  it  is  brought  from  Aix. 

2.  Ordinary  oil. — In  the  district  of  Montpellier,  this  oil  is  prepared  by  pressing  the 
olives,  previously  crushed  and  mixed  with  boiling  water.  At  Aix,  the  ordinary  oil  is  made 
from  the  olives  which  have  been  used  for  ol)taiuing  the  virgin  oil.  The  paste,  which  has 
been  previously  pressed,  is  broken  up,  a  certain  quantity  of  boiling  water  is  poured  over  it, 
and  it  is  then  again  submitted  to  the  press.  By  this  second  expression,  in  which  more 
pressure  is  applied  than  in  the  previous  one,  an  oil  is  obtained  somewhat  inferior  in  quality 
to  the  virgin  oil.     The  oil  is  separated  from  the  water  in  a  few  hours  after  the  operation. 

3.  oil  of  the  infernal  regions  {hnilc  d'cnfer). — The  water  which  has  been  employed  in 
the  preceding  operation,  is,  in  some  districts,  conducted  into  large  reservoirs,  called  the 
i)ifernal  regions,  where  it  is  left  for  many  days.  During  this  period,  any  oil  that  might 
have  remained  mixed  with  the  water  separates,  and  collects  on  the  suiface.  This  oil  being 
very  inferior  in  quality,  is  only  fit  for  burning  in  lamps,  for  which  it  answers  very  well. 
It  is  sometimes  called  lamp  oil. 

4.  Fermented  oil  (liuilefermentte). — This  is  obtained  in  the  two  above-named  districts,  by 
leaving  the  fresh  olives  in  heaps  for  some  time,  and  pouring  boiling  water  over  them  before 
pressing  the  oil.  But  this  method  is  very  seldom  put  in  practice,  for  the  olives  during  this 
fermentation  lose  their  peculiar  flavor,  become  much  heated,  and  acquire  a  musty  taste, 
which  is  communicated  to  the  oil. 

The  fruity  flavor  of  the  oil  depends  upon  the  quality  of  the  olives  from  which  it  has 
been  pressed,  and  not  upon  the  method  adopted  in  its  preparation. 


OILS. 


821 


There  are  met  with  in  commerce,  the  virgin  oil  of  Aix,  the  ordinary  oil  of  Montpelher 
and  Aix,  rarely  the  oil  by  fermentation,  and  never  the  oil  of  the  infernal  regions. 

When  olive  oil  is  mixed  with  nitrotis  acid  or  nitrate  of  mercury,  it  sohdifies  after  some 
time,  and  forms  a  solid  fat,  of  a  light  yellow  color,  which  is  called  claidinc.  It  is  the  oleine 
of  the  oil  that  is  affected,  and  appears  to  undergo  a  molecular  change,  for  the  elaidine  is  said 
to  have  the  same  ultimate  composition  as  oleine  itself. 

Olive  oil  is  used  as  food  and  in  salads,  hence  is  often  called  salad  oil ;  and  also  in  med- 
icine in  making  ointments,  &c.,  and  for  various  other  purposes. 

The  analyses  of  olive  oil  give  the  following  results: — 

Gav-Lussac  and 
'Thenard. 

-  77-21 

-  13-36 

-  9-43 


Lefort. 


Saussure. 

Carbon 

76-03 

Hvdrogen 

11-55 

Oxvgen 

12-07 

Nitrogen  (?)    - 

0-35 

100-00 


100-00 


-  77-51 

-  11-56 

-  10-93 

-     77-20 

■  11-35 

■  11-45 

100-00         100-00 


Owing  to  the  high  price  of  olive  oil,  it  is  frequently  adulterated  with  oils  of  less  value,  as 
poppy  oil,  &c.  This  will  be  more  fully  treated  of  when  speaking  of  the  adulteration  of  oils 
in  general. 

Oil  of  almonds. — The  tree  {Amygdalns  comiivmis)  which  yields  the  almond,  is  a  native 
of  Syria  and  Barbary,  but  is  now  abundant  throughout  the  south  of  Europe,  and  grows  even 
in  England,  though  here  the  fruit  seldom  ripens.  The  oil  is  obtained  by  expression  from 
the  bitter  or  sweet  almonds,  but  most  generally  from  the  former,  from  the  fact  of  their 
being  cheaper,  and  the  residual  cake  being  more  valuable,  yielding  by  distillation  with  water 
the  essential  oil  of  almonds ;  when  the  presence  of  water  is  carefully  avoided,  the  oil  obtain- 
ed from  them  is  quite  as  good  as  that  obtained  from  the  sweet  almonds ;  but  when  water 
is  present  with  the  almonds,  as  would  be  the  case  if  they  weie  deprived  of  their  skins  by 
maceration  in  water,  the  oil  would  possess  a  more  or  less  acrid  taste.  The  average  produce 
is  from  48  to  52  lbs.,  from  1  cvvt.  of  almonds  (Pereira).  When  recently  expressed  it  is 
turbid,  but  by  rest  and  filtration  becomes  perfectly  transparent.  It  possesses  generally  a 
slight  yellow  color,  which  becomes  considerably  paler  by  exposure  to  sunshine.  It  has  a 
mild,  bland  taste,  and  little  or  no  odor.  It  is  less  easily  congealed  by  cold  than  olive  oil. 
It  speedily  becomes  rancid,  and  should  be  kept  in  well  stoppered  bottles.  It  is  soluble  in 
25  parts  of  cold  alcohol,  and  in  6  parts  of  boiling  alcohol,  and  mixes  in  all  proportions  with 
ether.  It  is  used  for  the  same  purposes  as  olive  oil,  in  medicine,  &c. ;  it  is  nutritious,  but 
difficult  of  digestion  ;  it  is  often  used  mixed  with  gum  or  yolk  of  egg  as  an  emulsion. 

Oil  of  almonds  has  the  following  composition : — 

Lefort. 


Saussure. 

Oil  of  sweet  almonds. 

Carbon 

77-40 

-        70-42 

-     70-68 

Hvdrogen 

11-48 

-       10-77 

-     10-67 

Oxvgen 

10-83 

-       18-81 

-     18-65 

Nitrogen  ( '? ) 

0-29 

- 

- 

Oil  of  bitter  almonds. 
70-36  -  70-72 
10-50  -  11-01 
19-14     -     18-27 


100-00  100-00  100-00  100-00        100-00 

Almond  oil  is  sometimes  adulterated  with  olive  oil,  poppy,  and  teel  oil,  and  some  com- 
mercial samples  of  oil  seem  to  be  only  olive,  mixed  with  a  little  almond  oil. 

Tcel  oil,  or  oil  of  scsaimon. — The  seeds  which  yield  this  oil  are  obtained  from  the  Sesa- 
mum  orientale,  and  are  much  esteemed  in  South  Carolina,  where  they  are  called  oily  grain; 
and  are  made  into  soups  and  puddings,  like  rice.  The  fresh  seeds  yield  a  warm,  pungent 
oil,  which  loses  its  pungency  after  a  year  or  two,  and  is  them  used  for  salad ;  it  is  often 
mixed  with  olive  oil  for  soups,  &c. 

Oil  of  Belien  or  Ben. — This  oil  is  obtained  by  expression  from  the  seeds  of  a  plant 
{Moringa  aplera)  indigenous  to  Arabia  and  Syria,  and  cultivated  in  the  West  Indies.  It  is 
colorless,  or  slightly  yellow,  without  odor,  and  possesses  a  mild  taste.  It  separates,  by  stand- 
ing, into  two  parts,  one  of  which  bears  a  very  low  temperature  without  congealing.  It  is 
neutral  to  test  paper,  and  becomes  .slowly  rancid.  It  is  used  in  the  manufacture  of  some 
perfumes,  to  dissolve  out  the  odoriferous  principle  of  the  flowers.     See  Perfumkky. 

Hy  saponificatioa  it  appears  to  yield  two  peculiar  acids  in  small  quantities,  benic 
and  iiioriiigic  achls. 

Beech  oil. — The  nuts  of  the  beech  tree  (Fagus  sylmtica)  yield  about  12  ]ier  cent,  of  a 
clear  oil,  and  5  per  cent,  of  a  turbid  oil.  The  clear  oil  is  slightly  yellow,  without  odor,  and 
very  thick.  Its  density  at  60°  V.  is  -9225.  At  \'  V.  it  becomes  a  yellowish  mass.  It  is 
employed  in  cooking  in  France,  and  also  for  illuminating  purposes. 

Tiie  poor  people  of  Silesia  use  this  oil  instead  of  butte- 


822 


OILS. 


Oil  of  muatard. — The  seeds  of  white  mustard  {Sinapis  alba)  yield  about  36  per  cent, 
of  a  yellow  fatty  oil,  without  odor,  of  a  density  of  •9142  at  60"  F.,  and  does  not  solidify  by 
cold.  The  seeds  of  the  black  mustard  {Sinapis  nigra)  yield  about  18  per  cent,  of  a  similar 
oil.     It  may  be  used  for  soups,  &c. 

Rape-Ki-ed  oil. — This  oil  is  prepared  by  expression  from  the  seeds  of  several  kinds  of 
brassica ;  the  Brassica  napus  yields  about  33  per  cent,  of  oil  of  sp.  gr.  •9128;  and  the 
Brassica  rap<e  a  much  smaller  quantity  of  a  similar  oil  of  sp.  gr.  ^9167.  None  but  the 
diiest  seeds  are  used,  and  these  are  often  submitted  to  heat  in  order  to  coagulate  the  albu- 
men ;  but  the  oil,  when  first  obtained,  requires  considerable  purification  before  being  fit  for 
the  purposes  to  which  it  is  applied.  Thcnard's  process,  before  mentioned,  answers  well. 
Dr.  Rudolph  Wagner  has  found  that  a  solution  of  chloride  of  zinc  may  be  advantageously 
substituted  for  sulphuric  acid  in  the  clarification  of  rape  oil.  The  solution  of  the  chloride 
used  is  of  sp.  gr.  1^85,  and  is  used  in  the  proportion  of  lA  per  cent,  of  the  crude  oil.  The 
mijXture  is  then  shaken,  and  at  first  the  oil  becomes  yellow,  then  dark  brown,  and  after  a 
few  days  a  dark  brown  deposit  takes  place.  The  oil  is  still  turbid,  but  by  adding  hot  water 
and  passing  steam  through  it,  it  is  rendered  clear,  and  the  chloride  of  zinc  separated. 

Dcutsch  recommends  to  subject  the  rape  oil  to  heat  until  it  begins  to  decompose,  and 
keep  it  in  a  state  of  gentle  ebullition  for  a  few  hours;  a  scum  forms  and  separates,  and  the 
oil  becomes  transparent  and  greenish.  After  two  or  three  days'  repose  the  clear  oil  is 
drawn  off,  and  is  fit  for  use. 

Warburton's  method  is  to  agitate  the  oil  with  a  certain  quantity  of  a  solution  of  caustic 
soda,  which  dissolves  the  impurities,  these  separating  with  the  small  quantity  of  soap 
formed ;  the  oil  is  afterwards  well  washed  with  water  and  collected. 

Rape  oil  is  of  a  light  yellow  color,  peculiar  taste  and  smell,  which  increase  as  the  oil  is 
heated. 

It  is  employed  for  illuminating,  for  the  manufacture  of  soft  soaps,  for  the  oiling  of 
woollen  stuffs  in  the  process  of  their  manufacture,  in  the  preparation  of  leather,  and  also 
for  lubricating  machinery. 

The  English  rape-seed  seems  to  yield  the  best  oil. 

Butter  of  cacao. — This  is  ol)tained  from  the  cacao  nut,  the  seed  of  a  tree  {Thcobroma 
cacao)  which  is  largely  cultivated  in  South  America.  The  nuts  yield  about  50  per  cent,  of  this 
substance,  which  is  either  expressed  by  the  aid  of  heat,  or  by  boiling  the  crushed  seeds 
with  water.  It  is  yellowish,  Init  may  be  obtained  almost  colorless  by  melting  in  hot  water. 
It  has  the  consistence  of  suet.  It  presents  the  odor  and  the  taste  of  the  cacao  nut.  Its 
density  is  ^91;  it  fuses  at  86"  F.,  but  docs  not  solidify  again  till  cooled  to  73"  F.  It  is 
composed  in  a  great  part  of  stearine,  with  very  little  oleine.  It  may  be  kept  for  a  very 
long  time  without  becoming  rancid,  and  on  this  account  it  is  sometimes  used  in  pharmacy. 

Plum  kernel  oil. — The  kernels  of  the  plnm  (Pnorii.^  doincfitici/s)  deprived  of  their  skin, 
yield  about  33  per  cent,  of  a  transparent  oil,  of  a  brownish  yellow  color,  and  of  a  taste 
resembling  that  of  oil  of  sweet  .almonds.  Its  sp.  gr.  is  ■91'27;  and  solidifies  at  16"  F. 
It  speedily  becomes  rancid.  It  is  prepared  especially  in  Wurtemburg,  and  is  employed  for 
lighting,  for  which  it  answers  very  well. 

C'oroanui  oil. — The  trees  [Cocos  iiucifero',  &c.)  which  yield  the  cocoanut  are  natives 
of  tropical  climates,  five  varieties  being  indigenous  to  Ceylon.  A  powerful  oil  is  extracted 
from  the  bark,  and  is  used  by  the  Cingalese  as  an  ointment  in  cutaneous  diseases.  The 
cocoanut  oil  of  commerce  is  obtained  from  the  kernel  of  the  nut.  Two  processes  are  used 
for  its  extraction  in  Malabar  and  Ceylon  ;  viz.,  by  pressure,  aided  by  heat,  or  by  boiling  the 
bruised  kernel  with  water,  and  skimming  off  the  oil  as  it  forms  on  the  suifacc.  It  is  a 
white  solid,  po.s.^essing  a  peculiar  odor  and  mild  taste.  It  fuses  at  about  70"  F.  It  is  com- 
posed principally  of  a  peculiar  fat,  cociuine,  and  a  small  quantity  of  oleine.  It  speedily  be- 
comes rancid.  We  receive  it  principally  from  South  America.  It  is  employed  in  the  manu- 
facture of  candles  and  soap,  and  serves  particularly  for  the  manuAicture  of  a  marine  soap, 
which  forms  a  lather  with  sea-water.  It  is  used  laigely  in  India  and  Ceylon  ai,a  pomatum, 
and  is  there  prized  for  that  purpose,  but  its  speedily  becoming  rancid  prevents  its  use  here. 

Pahii  oil. — This  oil  is  extracted  from  the  fruit  of  one  of  the  palm  trees,  some  say  the 
Cocos  buti/rncea,  and  others  the  Avoira  elais.  The  oil  resides  in  the  fleshy  portion  of  the 
fniit,  which  is  about  the  size  of  pigeons'  eggs,  ovate,  somewhat  angular,  deep  orange 
yellow,  collected  in  heads.  They  liave  a  thin  epicaip,  a  fibrous,  oily,  yellow  sarcocarp, 
whieh  covers  and  closely  adheres  to  the  hard  stony  putamen  or  endocarp,  within  which  is 
the  seed.  The  oil  is  obtained  from  the  sarcocarp,  and  in  this  respect  resembles  the  olive. 
It  is  ol)tained  cither  by  expression  or  by  boiling  the  fruit  with  water,  when  the  oil  separates 
and  rises  to  the  surface.  It  is  imported  princi[)ally  from  Cayenne  and  the  coasts  of  Guinea. 
It  is,  when  freshly  nnported,  of  the  consistence  of  tallow,  of  an  orange  color,  and  possesses 
the  smell  of  violets,  and  fuses  at  about  80"  F.  It  speedily  becomes  rancid  and  decomposes 
with  liberation  of  glycerine  and  the  fatty  aciils,  and  as  this  change  progresses,  its  fusing 
point  gradually  rises  till  it  sometimes  even  reaches  97"  F.  It  is  composed  principally  of  a 
peculiar  fat,   palmitiu,  and  a  little  oleine  and  coloring  matter.     It  is  used  in  the  manu- 


OILS. 


823 


facture  of  soap  and  candles,  and  is  imported  in  very  large  quantities.  The  following  is  a 
general  outline  of  the  treatment  of  palm  oil  at  Price's  Candle  Company's  works  in  1855 
{Pharmaceutical  Journal,  vol.  xv.  p.  264).  The  crude  palm  oil  is  melted  out  of  the  casks 
in  which  it  has  been  imported,  and  allowed  to  remain  in  a  melted  state  in  large  tanks  until 
the  mechanical  impurities  have  settled  to  the  bottom.  The  clear  oil  is  then'  pumped  into 
close  vessels,  where  it  is  heated  and  exposed  to  the  action  of  sulphuric  acid.  The  gl3'cerine 
and  fatty  acids  are  thereby  separated,  and  the  coloring  matter  and  impurities  are  carbonized 
and  partly  rendered  insoluble.  The  mixture  has  now  a  grayish-brown  color,  and  is  washed 
with  water  to  remove  the  acid.  From  the  washed  product,  distillation  now  separates  the 
mixed  fatty  acids  (palmitic  and  palm-oleic  acids),  as  a  white  crystalline  fat,  while  the  resi- 
duum in  the  still  is  converted  into  a  fine  hard  pitch.  This  pitch  is  fit  for  any  of  the 
purposes  to  which  ordinary  pitch  is  applicable.  The  mixed  fatty  acids  may  be  made  direct- 
ly into  candles,  or  they  may  be  separated  by  hydraulic  pressure,  aided,  if  necessary,  by 
heat.  This  effects  the  separation  of  the  liquid  part  (oleric  acid),  which,  after  purification, 
is  fit  for  burning  in  lamps  and  other  purposes.  The  hard  cake  left  in  the  presses  is  nearly 
pure  palmitic  acid  ;  it  is  brilliantly  white,  not  at  all  greasy,  and  has  a  melting  point  of  135' 
to  l'i8\  It  is  fit  for  the  manufacture  of  the  finest  candles,  either  alone  or  in  admixture 
with  the  stearine  of  the  cocoanut  oil. 

Palm  oil  often  requires  to  be  bleached  for  its  various  uses,  and  there  are  several  process- 
es used  to  effect  it,  viz.,  chlorine,  powerful  acids,  and  the  combined  influence  of  air,  heat, 
and  light. 

M.  Pohl  has  bleached  palm  oil  by  heating  it  quickly  to  464"  F.  and  keeping  it  at  that 
temperature  for  a  few  minutes,  without  the  aid  of  light  or  air.  And  he  says  this  process 
has  been  carried  on  for  some  time  in  a  factory.  The  heating  of  the  palm  oil  is  effected  as 
rapidly  as  possible  in  cast-iron  pans  ;  it  is  kept  for  ten  minutes  at  the  temperature  of  464^ 
F,,  and  the  bleaching  is  complete.  Ten  or  twelve  hundred-weight  of  palm  oil  may  be 
conveniently  heated  in  one  pan,  which,  however,  must  only  be  two-thirds  full,  as  the  oil 
expands  greatly  by  the  heat.  It  must  be  covered  with  a  well  fitted  cover,  which  prevents 
inconvenience  from  the  disagreeable  vapors  which  arise.  This  answers  better  on  the  large 
scale  than  on  the  small.  By  this  process  it  acquires  an  empyreumatic  odor,  which  dis- 
appears after  a  little  time,  and  the  original  odor  of  the  palm  oil  returns. 

The  yellow  fat  which  is  used  to  grease  tlve  axle-trees  of  the  railway  carriages,  is  prepared 
with  a  mixture  of  palm  oil  and  tallow,  with  which  is  mixed  a  little  soda  lye  {Gerhardt). 

For  the  properties  oi palmitin  and  palmitic  acid  see  Palmitic  acid. 

Laurel  oil. — This  oil  is  known  also  under  the  name  of  "oiV  o/ ia vs,"  and  is  obtained 
from  either  the  fresh  or  dried  berries  of  the  bai/  tree  {Laurus  nobilix),  which  grows 
principally  in  the  south  of  Europe,  and  is  ulso  cultivated  in  our  gardens,  the  leaves  being 
used  by  the  cook  on  account  of  their  flavor.  The  berries  were  analyzed  by  Bonastre  in 
1824,  and  amongst  other  things,  were  volatile  oil,  0"8,  laurin  (camphor  of  the  bay  berry), 
ro,  and  fixed  oil,  128,  in  100  parts  of  the  berries.  Duhamel  states  that  the  fixed  oil  is 
obtained  from  the  fresh  and  ripe  berries  by  bruising  them  in  a  mortar,  boiling  them  for 
three  or  four  hours  in  water,  and  then  pressing  them  in  a  sack.  The  expressed  oil  is  mixed 
with  the  decoction,  and  on  cooling  is  found  floating  on  the  surface  of  the  water.  When  the 
dried  berries  are  used  they  are  first  subjected  to  the  vapor  of  water  until  they  are  well 
soaked,  and  are  then  rapidly  pressed  between  heated  metallic  plates.  By  the  latter  process 
they  yield  one-fifth  of  their  weight  of  oil.  It  is  imported  in  barrels  from  Trieste.  It  has  a 
butyiaceous  consistence  and  a  granular  appearance.  Its  color  is  greenish,  and  its  odor  like 
that  of  the  berries.  Cold  alcohol  extracts  from  it  the  essential  oil  and  green  coloring 
matter,  leaving  the  lauro-steariiie,  which  composes  the  principal  part  of  it.  With  alkalies 
it  forms  soaps.  But  its  principal  use  is  in  medicine,  and  more  particularly  in  veterinary 
medicine.  It  has  been  used  as  a  stimulating  liniment  in  sprains  and  bruises,  and  in  pa- 
ralysis. 

Natiiw  oil  of  laurel  (Hancock) ;  Laurel  turpentine  (Stenlioufie). — Imported  from  Deme- 
rara ;  obtained  by  incisions  in  the  bark  of  a  large  tree,  called  by  the  Spaniards  "  A-etjte  de 
sansafrati"  growing  in  the  vast  forests  between  the  Orinoco  and  the  Pariinc.  This  oil  is 
transparent,  slightly  yellow,  and  smells  like  turiwjntine,  but  more  agreeable,  and  approach- 
ing to  oil  of  lemons.  Its  sp.  gr.  at  50 '  F  is  0'8645.  It  consists  of  two  or  more  oils 
isomeric  with  each  other,  and  with  oil  of  turpentine.  Its  color  is  due  to  a  little  resin.  It 
is  an  excellent  solvent  for  caoutchouc  {Pereira). 

Ground-nut  oil. — This  is  obtained  from  the  fruit  of  the  (ground-nut  plant  {Arachix 
hjipogoea).  OstiM-meier  states,  that  a  considerable  ([uantity  of  the  earth-nut  having  been 
imported  into  Bremen,  without  finding  a  market,  the  importers  expresseil  the  oil,  which  is 
sold  under  the  name  »t'  earth-nut  oil.  According  to  Dr.  Buchnei-,  this  plant  belongs  to  the 
leguminosa?,  and  the  fruit  is  a  netted  yellowi.sh  gray  pod,  of  from  one  to  three  inches  long, 
and  four  to  nine  lines  tJiick,  in  which  are  contained  two  or  three  brownish-red  ovate  seeds, 
of  the  size  of  a  small  hazel-init.  Their  parenchyma  is  white,  very  nutritious  and  oily,  on 
wiiich  account  the  Arachis,  which  is  indigenous  to  the  tropical  parts  of  Aincrie;i,  has  been 


824 


OILS. 


transplanted  to  Asia  and  Africa,  and  even  to  the  south  of  Europe ;  and  is  in  that  climate 
frequently  cultivated  and  employed  for  the  manufacture  of  the  oil.  The  oily  seeds  possess 
a  sweet  taste,  somewhat  like  that  of  haricot  beans,  and  are  used  in  tropical  climates,  partlv 
raw,  and  partly  prepared  into  a  sort  of  chocolate,  which,  however,  is  not  equal  to  that  pre- 
pared from  cacao.  The  oil  is  employed  for  the  same  purposes  as  olive  oil.  It  is  of  a 
somewhat  greenish  color,  and  has  a  sp.  gr.  of  '9163  at  60'Fahr.  It  is  only  slightly  soluble 
in  alcohol  (one  part  in  lOo).  Its  smell  at  ordinary  temperatures  is  scarcely  perceptible,  but 
if  heated  to  122^  or  1G7^  Fahr.  it  acquires  a  smell  like  sweet  oil,  and  the  haricot  beans,  but 
is  not  disagreeable.  Its  taste  is  not  quite  so  agreeable  as  that  of  almond  oil  and  olive  oil. 
At  about  34^  Fahr.  the  arachis  oil  (from  Bremen)  congeals  into  a  viscid  mass  like  a  lini- 
ment, without  depositing  any  thing,  by  which  it  is  distinguished  from  oil  of  almonds  and 
olive  oil.  Although  not  a  drying  oil,  it  does  not  solidify  when  treated  with  nitrous  acid  or 
nitrate  of  mercury,  and  by  this  also  may  be  known  from  olive  oil,  &c. 

Pinejf  tallow. — This  is  prepared  from  the  fruit  of  the  Valeria  Ivdica,  a  tree  which 
grows  in  Malabar.  It  is  obtained  by  boiling  the  fruit  with  water,  and  collecting  the  fat 
which  rises  to  the  surface.  It  is  white,  greasy  to  the  touch,  and  of  an  agreeable  odor.  Its 
fusing  point  is  at  about  95'.  It  sp.  gr.  at  59^  isO'92ti,  and  at  95'  0'89t)5.  Alcohol  extracts 
from  it  about  2  per  cent,  of  oleine,  possessing  an  agreeable  odor.  It  answers  well  for  the 
manufacture  of  soap  and  caudles,  but  is  little  known  in  this  country. 

Spindle-trce  oil. — The  oil  of  spindle-tree  {Exonijmus  Europ<f>if!)  is  yellowish,  rather 
thick,  with  the  odor  of  colza  oil,  of  a  bitter  and  acrid  taste.  It  is  solid  at  5'  Fahr.  It  gives 
to  hot  water  a  bitter  substance.  It  is  but  little  soluble  in  alcohol,  and  the  solution  has  an 
acid  reaction.     It  contains  margarine,  and  oleine,  and  some  benzoic  and  acetic  acids. 

Butter  of  nulmcfiR. — This  is  commonly  known  in  the  shops  as  ej-prcsxcd  oil  of  mace,  and 
is  prepared  by  beating  the  nutmegs  to  a  paste,  placing  them  in  a  bag  and  exposing  them  to 
steam,  and  afterwards  pressing  between  heated  plates.  It  is  imported  in  oblong  cakes 
(covered  by  some  leaves),  which  have  the  shape  of  common  bricks,  only  smaller.  It  is  of 
an  orange  color,  firm  consistence,  fragrant  odor,  like  that  of  nutmegs.  Schroder  found  16 
parts  of  the  oil,  expressed  by  himself,  contained  1  part  of  volatile  oil,  6  parts  of  brownish 
yellow  fat,  and  9  parts  of  a  white  fat.  The  volatile  oil  and  yellow  fat  are  both  soluVjle  in 
cold  alcohol  and  cold  ether ;  the  white  fat  soluble  in  alcohol  and  ether,  when  boiling,  but 
insoluble  in  them  when  cold.  By  saponification  it  yields  glycerine  and  myristic  acid  (C^' 
H'^'0^,HO).  A  false  article  is  sometimes  made,  composed  of  animal  fat,  boiled  with 
powdered  nutmegs,  and  flavored  with  sassafras  (Plni/fair).  The  geijuine  article  may  be 
known  by  being  soluble  in  four  times  its  weight  of  boiling  alcohol,  or  half  that  quantity  of 
boiling  ether.  Its  principal  use  is  in  medicine.  It  must  not  be  confounded  with  essential 
oil  of  mace. 

The  Drying  Oils. 

Linseed  oil. — The  oil  is  obtained  by  expression  from  the  seeds  of  the  common  flax 
{Lininn  usitatissimum),  either  with  or  without  the  aid  of  heat;  the  latter,  being  known  as 
cold-drawn  linseed  oil,  is  better  than  that  expressed  by  heat.  By  cold  expression  the  seeds 
yield  about  20  per  cent,  of  oil,  but  by  the  aid  of  heat  from  22  to  27  per  cent.  The  cold- 
drawn  oil  is  of  a  light  yellow  color,  while  that  obtained  by  heat  is  brownish,  and  easily 
becomes  rancid.  It  has  a  peculiar  smell  and  taste.  According  to  Saussure  its  sp.  gr.  is 
0-9395  at  53-6°  Fahr.;  0-9125  at  122'  Fahr.  ;  and  0-8815  at  201"  Fahr.  At  4'  Fahr,  it 
becomes  paler  without  solidifying;  but  at  —17-5'  Fahr.  it  forms  a  solid  mass.  It  is  soluble 
in  5  parts  of  boiling  alcohol,  in  40  parts  of  cold  alcohol,  and  in  1-6  parts  of  ether. 

It  consists  principally  of  a  liquid  oil,  which  differs,  however,  as  before  mentioned,  from 
the  oleine  of  olive  oil  and  the  non-drying  oils  in  general,  and  is  called  linoleine,  and  yields 
by  saponification,  linoleic  acid.  It  also  contains  some  margarine,  and  generally  some 
vegetable  albumen  and  mucilage. 

Pure  linseed  oil  has  the  following  composition: — 

Sacc.  Lefort 


Caroon 
Hydrogen    - 
Oxygen 


78-05 
10-83 
11.12 


78-18 
11-09 
10-73 


7519     - 

10-85 

13-96 

75.14 

1112 

-     13-74 

100-00        100-00 


100-00 


100-00 


Linseed  oil  is  easily  saponified,  yielding  a  mixture  of  oleate  and  margarate  of  the  alkali, 
and  a  large  quantity  of  glycerine. 

It  is  acted  on  rapidly  by  nitric  acid,  producing  margaric  acid,  pimelie  acid,  and  some 
oxalic  acid. 

Chlorine  and  bromine  act  on  it,  yielding  thick  colored  products.  When  linseed  oil  is 
heated  in  a  retort,  it  gives  off,  before  entering  into  ebullition,  large  quantities  of  white 
vapors,  which  condense  to  a  limpid  colorless  oil,  possessing  the  odor  of  new  bread.     As 


OILS. 


825 


soon  as  the  ebullition  commences  these  vapors  cease  ;  the  oil  froths  up,  and  at  length  there 
Is  left  a  thick  n;('l:itiiious  residue,  very  much  resembling  caoutchouc. 

Tiie  principal  use  of  linseed  oil  is  in  making  paints  and  varnishes.  It  attracts  oxygen 
rapidly  from  the  air  and  solidifies,  and  this  property  is  what  renders  it  so  valuable  for  these 
purposes :  it  is  the  most  useful  of  all  the  drying  oils.  The  small  quantities  of  vegetable 
albumen  and  mucilage  which  the  oil  naturally  contains,  appear,  according  to  Licbig,  to 
impair,  to  a  certain  extent,  its  drying  properties,  and  the  real  object  which  is  obtained  by 
boiling  these  oils  with  litharge,  or  acetate  of  lead  and  litharge,  is  the  removal  of  these  sub- 
stances ;  the  oil  then  being  brought  more  directly  in  contact  with  the  oxygen  of  the  atmos- 
phere, dries  up  more  rapidly.  It  was  previously  thought  that  some  of  the  litharge  was 
reduced  to  metallic  lead,  oxidizing  at  the  same  time  some  of  the  linoleine ;  but  Liebig's 
opinion  seems  to  be  more  likely  to  be  correct.  The  boiling  of  the  oil  requires  some  little 
care.  A  few  hundredths  of  litharge  is  added  to  the  oil,  or  some  use  acetate  of  lead  and 
litharge,  and,  as  before  stated,  about  an  eighth  part  of  resin ;  this  is  boiled  with  the  oil,  the 
scum  removed  as  it  forms,  and  when  the  oil  has  acquired  a  reddish  color,  the  source  of  heat 
is  removed,  and  the  oil  allowed  to  clarify  by  repose.  Liebig  thinks  heat  is  not  necessary, 
and  his  process  for  treating  the  drying  oils,  in  order  to  increase  their  siccative  properties, 
has  already  been  mentioned.  According  to  MM.  E.  Barruel  et  Jean,  the  resinification  of 
the  drying  oils  may  be  effected  by  the  smallest  quantities  of  certain  substances,  which 
would  act  in  the  manner  of  ferments.  The  borate  of  manganese  acts  in  this  way ;  a  thou- 
sandth part  of  this  salt  being  sufficient  to  determine  the  rapid  desiccation  of  these  oils. 

Linseed  oil  is  used  in  the  manufacture  of  printers'  ink ;  being  heated  in  a  vessel  until  it 
takes  fire,  it  is  allowed  to  burn  some  time,  then  it  is  tightly  covered ;  and  subsequently 
mixed  with  about  one-sixth  of  its  weight  of  lamp-black. 

The  thin  gummed  silks  receive  the  last  of  their  many  layers  with  boiled  linseed  oil ;  it  is 
also  used  for  leather  varnishes,  and  for  oil-ck)ths. 

The  residue,  after  the  expression  of  the  oil  from  the  seeds,  is  called  oil-cake,  and  is  sold 
for  feeding  cattle ;  that  obtained  from  the  English  linseed  is  the  best. 

Walnut  oil. — This  is  obtained  by  expression  from  the  ordinary  walnuts  deprived 
previously  of  their  skin,  which  are  the  produce  of  a  tree  {Jaglans  regia)  which  is  a  native 
of  Persia,  but  cultivated  in  this  country  for  the  sake  of  the  nuts. 

When  recently  prepared  it  is  of  a  greenish  color,  but  by  age  becomes  a  pale  j'cllow. 
According  to  M.  Saussure  its  sp.  gr.  at  53-6^  Fahr.  is  0-9283,  and  at  201"  Fahr.,  0-871.  It 
has  no  odor  and  an  agreeable  taste.  At  6°  Fahr.  it  thickens,  and  at  17"5^  Fahr.  it  forms 
a  whitish  mass.  The  nuts  yield  about  50  per  cent,  of  oil.  It  dries  still  more  rapidly  even 
than  the  linseed  oil.  It  is  principally  used  for  paints  and  varnishes,  and  from  its  lighter 
color,  it  is  often  used  for  white  paints. 

Oil  of  the  Hazd-md. — This  is  extracted  from  the  seeds  of  the  Corylus  avellana,  which 
yield  about  60  per  cent,  of  the  oil.  It  is  liquid,  has  only  a  slight  color,  no  odor,  and  a  mild 
taste.     Its  sp.  gr.  at  59''  Fahr.  is  0-9242.     At  14°  Fahr.  it  solidifies. 

Poppy  (Yd. — This  is  expressed  from  the  seeds  of  the  common  poppy,  (Papaver  soni- 
7iiferum,)  wliich  grows  wild  in  some  parts  of  England.  It  is  cultivated  in  very  large  quan- 
tities in  Hindostan,  Persia,  Asia  Minor,  and  Egypt,  for  the  sake  of  the  opium  which  is  ob- 
tained from  the  capsules.  It  is  cultivated  in  Europe  for  the  capsules,  which  are  used  in 
medicine,  or  for  the  oil  extracted  from  the  seeds.  The  oil  is  obtained,  by  expression,  from 
the  seeds,  which  do  not  possess  any  of  the  narcotic  properties  of  the  capsules.  These  seeds 
are  sold  for  birds,  under  the  name  of  jnaw-seed. 

This  oil  resembles  olive  oil  in  its  appearance  and  taste,  and  is  often  used  to  adulterate  it. 
Its  sp.  gr.  at  59'  Fahr.  is  0  9249.  It  becomes  solid  at  0^  Fahr.  It  is  soluble  in  25  parts 
of  cold  alcohol,  and  in  6  parts  of  boiling  alcohol,  and  may  be  mixed  in  all  proportions  with 
ether.  It  is  used  sometimes  for  lighting,  and  after  treatment  with  Jitharge  or  subacetate  of 
lead  is  used  for  paints. 

Hempxeed  Oil. — The  seeds  of  the  common  hemp  (Cannabis  .tafira)  yield,  by  expres- 
sion, from  14  to  25  per  cent,  of  their  weight  of  a  fixed  oil.  It  is  obtained  principally  from 
Russia,  but  the  native  places  of  the  plant  are  Persia,  Caucasus,  and  hills  in  the  north  of 
India.  The  seeds  are  small  ash-colored  shining  bodies.  Tiiey  are  demulcent  and  ol(>aginous, 
but  possessing  none  of  the  narcotic  properties  of  the  plant.  They  arc  employed  for  feed- 
ing cage-birds,  and  it  has  been  stated  that  the  plumage  of  certain  birds,  as  the  bulHinch 
and  goldfinch,  becomes  changed  to  black  by  the  prolonged  use  of  this  seed.  Wiien  fresh, 
this  oil  is  greenish,  but  becomes  yellow  by  age.  It  has  a  <lisagreeable  odor,  and  insipid 
taste.  It  is  soluble  in  all  proportions  in  ])oiling  alcohol,  but  requires  30  parts  of  cold  alco- 
hol to  dissolve  it.  It  thickens  at  5"  Fahr.,  and  becomes  solid  at  17-5"  Fahr.  It  is  some- 
times used  for  illuminating  purposes,  but  being  a  drying  oil,  it  forms  a  thick  varnish,  and 
thus  clogs  the  wick  ;  it  is  used  also  in  making  soft  soap,  and  in  paints.  When  boiled  with 
litharge  or  subacetate  of  lead,  it  forms  a  good  varnish. 

Su7i.fiowcr  Oil. — The  seeds  of  the  sunflower  {Ildianthua  annuus)  yield  about  15  per 
cent,  of  a  limpid  oil,  having  a  clear  yellow  color ;  it  has  an  agreeable  odor,  and  mawkish 


820  OILS. 

taste  ;  its  sp.  gr.  at  60"  is  -9263.     At  9'  Fahr.  it  becomes  solid.     It  is  sometimes  employed 
as  food,  as  well  as  for  illuminating  purposes,  and  for  making  soap. 

Castor  Oil. — The  castor  oil  plant  has  been  known  from  the  remotest  ages.  Caillaud 
found  the  seeds  of  it  in  some  Egyptian  sarcophagi,  supposed  to  have  been  at  least  4,00(7 
years  old.  Some  people  imagine  it  is  the  same  plant  that  is  called  the  gourd  in  Scripture, 
it  was  called  KpSrui/  by  the  Greeks,  and  ricinics  by  the  Romans.  It  is  a  native  of  India, 
where  it  sometimes  grows  to  a  considerable  size,  and  lives  several  years.  When  cultivated 
in  Great  Britain,  it  is  an  annual,  seldom  exceeding  three  or  four  feet.  There  appear  to  be 
several  varieties  of  the  ricinns  ;  the  officinal  is  the  Ricinus  coitwiunis,  or  Palma  Christi. 

The  seeds  are  oval,  somewhat  compressed,  about  four  lines  long,  three  lines  broad,  and 
a  line  and  a  half  thick  ;  externally  they  are  pale  gray,  but  marbled  with  yellowish-brown 
spots  and  stripes. 

The  oil  may  be  obtained  from  the  seeds  by  expression,  by  boiling  with  water,  or  by  the 
agency  of  alcohol.     Nearly  all  that  is  consumed  in  England  is  obtained  by  expression. 

In  America  the  seeds  cleansed  from  the  dust  and  iragments  of  the  capsules  are  submit- 
ted to  a  gentle  heat,  not  greater  than  can  be  borne  by  the  hanS,  which  is  intended  to  render 
the  oil  more  liquid,  and  therefore  more  easily  expressed.  They  are  then  submitted  to  pres- 
sure in  a  screw-press  :  the  whitish  oily  liquid  thus  obtained  is  boiled  with  a  large  quantity 
of  water,  and  the  impurities  skimmed  off  as  they  rise  to  the  surface.  The  water  dissolves 
the  mucilage  and  starch,  and  the  albumen  is  coagulated  by  the  heat,  forming  a  layer  between 
the  oil  and  water.  The  clear  oil  is  now  removed,  and  boiled  with  a  very  small  quantity  of 
water  until  aqueous  vapor  ceases  to  arise,  and  a  small  portion  of  the  oil  taken  out  in  a  phial 
remains  perfectly  transparent  when  cold.  The  eflfect  of  this  operation  is  to  clarify  the  oil, 
and  to  get  rid  of  the  volatile  acrid  matter.  Great  care  is  necessary  not  to  carry  the  heat 
too  far,  as  the  oil  would  thus  acquire  a  brownish  color  and  acrid  taste. 

In  the  West  Indies  the  oil  is  obtained  by  decoction,  but  none  of  it  appears  in  commerce 
in  this  country. 

In  Calcutta  it  is  thus  prepared  : — The  fruit  is  shelled  by  -women  ;  the  seeds  are  crushed 
between  rollers,  then  placed  in  hempen  cloths,  and  pressed  in  the  ordinary  screw  or  hydrau- 
lic press.  The  oil  thus  obtained  is  afterwards  heated  with  water  in  a  tin  boiler  until  the 
water  boils,  by  which  means  the  mucilage  and  albumen  are  separated.  The  oil  is  then 
strained  through  flannel  and  put  into  canisters. 

Two  principal  kinds  of  castor  seeds  are  known,  the  large  and  the  small  nut ;  the  latter 
yields  the  most  oil,  {Ferelra.')  The  best  East  Indian  castor  oil  is  sold  in  London  as  "  cold- 
drawn." 

In  some  parts  of  Europe  castor  oil  has  been  extracted  from  the  seeds  by  alcohol,  but 
the  process  is  more  expensive,  and  yields  an  inferior  article. 

Castor  oil  is  a  viscid  oil,  generally  of  a  pale  yellow  color,  a  nauseous  smell  and  taste. 
Its  sp.  gr.  according  to  Saussure  is  0-969  at  53°  F.  The  acrid  taste  which  it  sometimes  pos- 
sesses, may  be  removed  from  it  by  magnesia,  (Gerfiardt.)  At  about  0°  F.  it  forms  a  yellow, 
solid,  transparent  mass.  By  exposure  to  the  air,  it  becomes  rancid,  thick,  and  at  last  dries 
up,  forming  a  transparent  varnish.  It  dissolves  easily  in  its  own  volume  of  absolute  alco- 
hol ;  castor  oil  and  alcohol  exercise  a  mutual  solvent  power  on  each  other,  (Fereira.)  It  is 
also  equally  soluble  in  ether. 

Pereira  states  that  there  are  chiefly  three  sorts  of  castor  oil  found  in  the  London  mar- 
ket ;  viz.,  the  oil  expressed  in  London  from  imported  seeds.  East  Indian  oil,  and  the  Ameri- 
can or  United  States  castor  oil.  Castor  oil  is  imported  in  casks,  barrels,  hogsheads,  and 
duppers.     It  is  purified  by  decantation  and  filtration,  and  bleached  by  exposure  to  sunlight. 

It  is  not  quite  decided  how  many  kinds  of  fats  castor  oil  contains ;  according  to  Ger- 
hardt,  several,  but  Saalmuller  says  only  two.  It  is,  however,  principally  composed  of 
rici7iol('ine,  with  perhaps  a  little  stearine  and  palmitine,  and  an  acrid  resin.  Its  ultimate 
composition  is  shown  by  the  following  analyses  : — 

Urc.  Saussure. 

Carbon    ....        '7400  74-18 

Hydrogen         -         -        -         10-29  11-03 

Oxygen    -        -        -        -         1571  1479 


Lefort. 

74-58 
11-48 
13-94 

74-35 
11-35 
14-30 

100-00  100-00  100-00       100-00 

When  castor  oil  is  heated  in  a  retort  to  509°  F.,  an  oleaginous  liquid  distils  over,  with- 
out the  liberation  of  much  gaseous  matter ;  about  the  third  part  of  the  oil  thus  passes  over. 
If  after  this  it  is  further  heated,  it  froths  up,  but  if  the  distillation  is  stopped  before  it  be- 
gins to  froth  up,  there  remains  in  the  retort  a  substance  insoluble  in  water,  alcohol,  ether, 
the  fatty  and  essential  oils  ;  this  is  treated  with  ether  to  remove  any  undccomposed  castor 
oil,  then  dissolved  in  potash ;  the  soap  thus  formed  yields  a  fatty  acid,  viscid  at  ordinary 
temperatures,  very  soluble  in  absolute  alcohol,  but  little  soluble  in  weak  spirit.  The 
volatile  products  of  the  distillation  contained  anantliolc^  anantliylic  acid,  some  acroleinc, 
and  solid  fattv  acids. 


OILS.  827 

Hvponitric  acid  solidifies  castor  oil,  and  nitric  acid  when  boiled  with  it  converts  it  into 
oenanthylic  and  suberic  acids. 

Castor  oil  is  said  to  he  adulterated  sometimes  with  croton  oil  to  increase  its  activity ; 
this  is  a  dangerous  sophistication  ;  it  is  also  mixed  with  some  cheap  fixed  oils.  The  latter 
adulteration  has  been  said  to  be  detected  by  the  solubility  of  castor  oil  in  alcohol,  but  un- 
fortunately castor  oil  may  contain  as  much  as  33  per  cent,  of  another  fixed  oil,  and  yet  be 
soluble  in'its  own  volume  of  alcohol,  {Pereira,)  this  oil  possessing  the  property  of  render- 
ing other  oils  soluble  in  spirit. 

Grapcseed  Oil. — The  grapestones  (Vitis  vinifera)  yield  about  11  per  cent,  of  their 
weight  of  a  fixed  oil,  which  is,  when  fresh,  of  a  clear  yellow  color,  but  becomes  brown  by 
age.  It  has  an  insipid  taste,  and  little  or  no  color.  Its  sp.  gr.  at  60"  F.  is  -9202 ;  at  3°  F. 
it  becomes  solid.  It  is  not  of  much  value  for  illuminating  purposes,  but  in  some  southern 
localities  it  is  used  for  food. 

Oil  of  the  Pine  and  Fir  Trees. — In  the  Black  Forest  In  Germany,  an  oil  is  extracted 
from  the  cleansed  seeds  of  the  Pinus  picea  and  Pinns  abies.  It  is  limpid,  of  a  golden  yel- 
low color,  and  resembles  in  smell  and  taste  the  oil  of  turpentine.  Its  sp.  gr.  is  0-93  at  60^ 
F.  It  is  very  fluid  and  dries  rapidly.  It  only  congeals  at — 22"  F.  It  answers  well  for 
the  preparation  of  colors  and  varnishes. 

Oil  of  Camdina. — This  is  extracted  from  the  seeds  of  the  Mijarjrinn  sativum  ;  it  is  of 
a  clear  yellow  color,  with  but  little  smell  or  taste,  and  dries  rapidly  by  exposure  to  the  air. 
It  is  used  for  lighting. 

TIte  Oil  of  Belladonna  Seeds. — This  oil  is  extracted  in  Wurtemburg  from  the  seeds  of 
the  Atropa  belladonna,  and  is  there  used  for  lighting  and  cooking.  It  is  limpid,  of  a  golden 
yellow  color,  insipid  taste,  and  no  odor.  All  the  poisonous  principles  of  the  plant  are  left 
in  the  seed-cake,  which  cannot,  therefore,  be  given  to  cattle.  The  odor  which  is  given  off 
during  its  extraction,  stupefies  the  workmen. 

Oil  of  Tubaceo  Seeds. — The  seeds  of  the  Nicotiana  tabacum  yield  about  31  per  cent, 
of  their  weight  of  a  drying  oil,  which  is  limpid,  of  a  greenish-yellow  color,  and  no  odor. 
It  does  not  possess  any  of  the  narcotic  princijiles  of  the  plant. 

Cotton-seed  Oil. — Many  attempts  have  been  made  to  render  fit  for  use  the  oil  obtained 
from  the  seeds  of  the  cotton  plant,  ( Gosstjpium  Barbadense,)  as  immense  quantities  of  these 
seeds  are  allowed  to  rot,  or  used  only  as  manure  upon  the  cotton  lands  of  the  south  of  the 
United  States  of  America.  When  obtained  by  expression,  the  oil  which  runs  from  the  press 
is  of  a  very  dark  red  color.  It,  however,  deposits  some  of  the  coloring  matter  by  standing, 
as  well  as  a  portion  of  semi-solid  fat ;  and  in  cold  weather  this  is  precipitated  in  large  quan- 
tities ;  and  only  partially  redissolves  again  by  increase  of  temperature.  The  great  obstacle 
to  the  use  of  the  oil  thus  obtained  is  its  color,  which  appears  to  be  derived  from  a  dark 
resinous  substance,  presenting  itself  in  small  dots  throughout  the  seed.  These  may  readily 
be  seen  by  examining  a  section  of  the  seeds  with  a  lens,  or  even  with  the  naked  eye,  {Mr. 
Wayne,  Pliarmaceutical  Journal,  xvi.  335.)  lu  bleaching,  the  oil  loses  from  10  to  15  per 
cent.,  a  portion  of  which  may  be  again  recovered  and  used  for  making  soap,  for  which  pur- 
pose cotton-seed  oil  seems  best  fitted.  It  is  a  drying  oil,  and  consequently  not  well  fitted 
for  machinery ;  and  when  burnt,  rapidly  clogs  the  wick.  A  very  good  soap  for  common 
purposes  is  made  from  it  in  New  Orleans.  Mr.  Wayne  also  states,  "  that  the  oil,  to  be  made 
profitalily,  should  either  be  manufactured  in  the  vicinity  of  the  cotton  plantation,  as  the 
seeds,  from  the  attached  fibre,  are  bulky,  and  the  cost  of  transportation  great ;  or  the  seed 
should  be  hulled  at  the  spot,  and  shipped  to  the  place  where  it  is  to  be  pressed  in  that  con- 
dition, as  it  requires  three  or  four  bushels  of  seed  in  the  wool  to  produce  one  bushel  of 
hulled  seed  ready  for  the  mill.  The  hull  and  attached  fibre  are  useful  for  paper  stock  ;  and 
the  cake,  left  after  the  extraction  of  the  oil,  is  nearly  as  valuable  a  food  for  cattle  as  that 
of  linseed. 

"  It  appears  that  boiling  the  crushed  seeds  with  water  yields  a  very  bland,  light-colored 
oil. 

"  The  desire  to  bring  this  oil  into  use  still  exists,  for  a  .sample  of  it  was  sent  a  few  months 
since  from  a  merchant  in  America  to  a  friend  of  mine  to  see  if  he  could  succeed  in  purify- 
ing it,  which  no  doubt  will  ultimately  be  effected  by  some  one." 

The  cotton  plant  grows  principally  in  the  south  of  the  United  States  of  America ;  but 
it  has  of  late  years  been  cultivated  in  India. 

Croton  Oil. — This  oil  is  obtained  from  the  seeds  of  the  Croton  Ticjlii,  by  expression, 
or  by  the  use  of  alcohol.     It  is  a  most  violent  purgative,  and  its  only  use  is  in  medicine. 
■  (For  a  lengthened  account  of  this  oil,  see  Pereira  s  Materia  Medica.) 

AxiMAi.  Oils. 

The  mode  of  the  formation  of  fats  in  animals  has  been  explained  upon  two  theories. 
That  of  Dumas,  and  supported  by  some  high  authorities,  which  considers  that  the  fats  arc 
not  formed  in  the  animals,  but  that  they  receive  the  fat  already  formed  from  the  vegetable 
kingdom,  the  herbivora  obtaining  it  from  the  vegetables  which  serve  Ihcm  for  food,  and  the 


828 


OILS. 


carnivora  obtaining  it  from  the  herbivora  on  which  they  feed.  No  doubt  some  of  the  ani- 
mal fats  are  thus  obtained,  but  doubtless  some  are  formed  in  the  manner  accounted  for  in 
the  opposing  theory  of  Liebig.  He  considers  that  the  fat  is  formed  principally  by  the  de- 
oxidation  of  the  amylaceous  and  saccharine  matters  taken  in  the  food.  Tlic?e  substances 
are  principally  consumed  in  respiration  when  the  animal  takes  much  exercise,  being  con- 
verted again  into  water  and  carbonic  acid,  from  which  they  were  tbrmerly  produced  by  the 
plants.  When  the  animal  is  kept  without  exercise,  the  respiration  is  less  vigorous,  and  if 
the  animal  at  the  same  time  be  fed  with  these  amylaceous  or  saccharine  substances,  the 
excess  of  these  is  converted  into  fat. 

Huber  of  Geneva,  several  years  since,  found  that  bees  did  not  obtain  their  wax  entirely 
from  plants ;  he  kept  some  bees  in  a  confined  place  and  fed  them  entirely  on  honey,  and 
they  formed  quite  as  much  wax  as  when  they  were  perfectly  at  liberty  amongst  the  flowers : 
in  this  way  he  proved  that  wax,  which  is  a  true  fat,  was  a  secretion  of  the  bee.  See  Nu- 
trition. 

The  only  oils  which  will  be  mentioned  here  are  lard  oil,  tallow  oil,  and  neat's-foot  oil. 

Lard  Oil. — This  oil  is  now  imported  largely  from  America,  and  is  obtained  by  subject- 
ing ordinary  hog's-lard  to  pressure,  when  the  liquid  part  separates,  while  the  lard  itself  be- 
comes much  harder.  It  is  employed  for  greasing  wool,  for  which  purpose  it  answers  very 
well,  and  may  be  oljtaincd  at  a  low  price.  According  to  Bracoimet,  lard  yields  0-62  of  its 
weight  of  this  oil,  which  is  nearly  colorless.  Sp.  gr,  0-915,  {Chevreul.)  100  parts  of  boil- 
ing alcohol  dissolve  r23  parts  of  it. 

Tallow  Oil. — This  oil  is  obtained  from  tallow  by  pressure.  The  tallow  is  melted,  and 
when  separated  from  the  ordinary  impurities  by  subsidence,  is  poured  into  vessels  and 
allowed  to  cool  slowly  to  about  80°,  when  the  stearine  separates  in  granules,  which  may  be 
separated  from  the  liquid  part  by  straining  through  flannel,  and  is  then  pressed,  when  it 
yields  a  fresh  portion  of  liquid  oil.  It  is  employed  in  the  manufacture  of  some  of  the  best 
soaps. 

Ne<d''s-foot  Oil. — After  the  hair  and  hoofs  have  been  removed  from  the  feet  of  oxen, 
they  yield,  when  boiled  with  water,  a  peculiar  fatty  matter,  which  is  known  under  the  name 
of  Neat's-foot  oil ;  after  standing,  it  deposits  some  solid  fat,  which  is  separated  by  filtration ; 
the  oil  then  does  not  congeal  at  32",  and  is  not  liable  to  become  rancid.  It  is  often  mixed 
with  other  oils.  This  oil  is  used  for  various  purposes,  especially,  owing  to  its  remaining 
liquid  at  so  low  a  temperature,  for  oiling  church  clocks,  which  require,  in  consequence  of 
the  cold  they  are  exposed  to,  an  oil  which  is  hot  liable  to  solidify. 

Fisn  Oils. 

Although  the  whale  is  not,  truly  speaking,  a  fish,  the  oil  obtained  from  it  is  classed  among 
the  fish  oils,  and  those  which  will  be  described  here  are,  whale  oil,  porpoise  oil,  seal  oil,  and 
cod-liver  oil.     The  three  former  are  all  known  under  the  name  train  oil. 

Whale  Oil. — The  capture  of  the  whales  is  a  large  commercial  undertaking ;  many  well- 
manned  ships,  and  fitted  out  at  great  expense,  proceed  every  year  from  England,  Holland, 
France,  and  other  nations,  into  the  arctic  zone  in  search  of  these  animals,  and  especially  the 
Greenland  species,  {Balcc7ia  mysticetus.)  This  valuable  animal  has  produced  to  Britain 
£700,000  in  one  year,  and  one  cargo  has  been  known  to  lie  worth  £11,000.  The  Green- 
land whale  inhabits  the  polar  seas  ;  its  length  is  from  60  to  70  feet,  when  full  grown.  When 
the  whales  are  captured  they  are  secured  alongside  the  ship,  and  the  process  of  flensing  com- 
mences. The  men,  having  shoes  armed  with  long  iron  spikes  to  maintain  their  footing,  get 
down  on  the  huge  and  slippery  carcass,  and  with  very  long  knives  and  sharp  spades  mal  e 
parallel  cuts  through  the  blubber,  from  the  head  to  the  tail.  A  band  of  fat,  however,  is  left 
around  the  neck,  called  the  kcnt,  to  which  hooks  and  ropes  are  attached  for  the  purpose  of 
shifting  round  the  carcass.  The  long  parallel  strips  are  divided  across  into  portions  weigh- 
ing about  half  a  ton  each,  and  being  separated  from  the  flesh  beneath  are  hoisted  on  board, 
chopped  into  pieces,  and  put  into  casks.  During  the  homeward  voyage  the  animal  matters, 
&c.,  attached  to  the  blubber,  undergo  decomposition  to  a  certain  extent,  while  there  is  at 
the  same  time  a  p(,'culiar  fat  formed,  which  is  a  compound  of  glycerine  and  ihoccinc  acid, 
and  which  imparts  the  disagreeable  odor  peculiar  to  train  oil.  I)umas  has  shown  that  this 
acid  is  identical  with  valerianic  acid.  After  the  decomposition  of  the  blubber,  the  oil  runs 
from  it  easily,  and  the  whole  is  put  into  casks  with  perforated  bottoms,  placed  over  tanks 
for  receiving  the  oil.  The  oil  is  heated  to  about  212°,  to  facilitate  the  separation  of  the 
impurities,  and  in  order  to  further  purify  it,  some  use  a  solution  of  tannin,  to  precipitate  the 
gelatine  present ;  others  use  different  metallic  salts,  as  acetate  of  lead.  On  the  western 
coast  of  Ireland  the  whale  is  sometimes  captured,  and  yields  a  large  quantity  of  very  good 
oil,  superior  to  sperm  oil  for  illuminating  purposes.  The  sperm  whale  (Pln/srla  mncroccph- 
ahts)  does  not  yield  so  much  oil  as  the  Greenland  whale,  but  yields  considerably  more  of  the 
valuable  substance  sfiermareti. 

Train  oil  is  of  a  brownish  color,  with  a  disagreecblc  odor ;  it  is  used  for  lighting,  in  the 
manufacture  of  soft  soaps,  and  in  the  preparation  of  leather. 

Referring  to  the  American  whale  fishery  for  1859,  the  Peterhead  Sentinel  says:   "  The 


OILS.  829 

result  is  not  so  satisfactory  as  we  bad  anticipated  ;  indeed,  it  will  be  seen  that  there  are  indi- 
cations of  a  gradual  decline.  Going  back  seven  years,  we  find  that  the  number  of  vessels 
wa.s  nearly  670;  on  the  1st  of  January,  1800,  it  was  only  571,  showing  a  decrease  as  com- 
pared with  the  previous  year  of  54  vessels,  with  an  aggregate  of  18,006  tons ;  and  it  is  cal- 
culated that  there  will  be  as  great  a  falling  off  during  the  current  year.  The  whole  imports 
of  1859  were  as  follows: — Sperm,  9,141  tons;  whale,  19,041  tons;  bone,  1,923,850  lbs. 
From  this  it  appears  that  there  has  been  an  excess  over  the  year  1858  in  sperm  of  940  tons  ; 
whale,  819  tons;  and  in  bone,  323,250  lbs.  The  exports  of  oil  and  bone  were,  sperm, 
5,221  tons;  whale,  818  tons;  and  bone,  1,707,929  lbs.  This  shows  that  the  export  of 
sperm  oil  in  1839  largely  exceeds  that  of  1858,  while  that  of  the  whale  has  been  light.  As 
regards  prices,  the  average  of  whale  oil  was,  in  1858,  2s.  3J.,  and  in  1859,  2s.  OW.  per  gal- 
lon. Daring  the  same  periods  the  prices  in  this  country  were  respectively  2s.  9t/.  and 
2s.  5(/.  per  gallon.  In  America,  sperm  oil,  in  1858,  was  5s.  5d,  and  in  1859,  5.s.  8c/.  per 
gallon,  against  7s.  to  8s.  in  this  country." 

Seal  Oil. — The  seal-fishery  of  Newfoundland  has  now  become  the  most  important  part 
of  the  trade  of  that  colony.  Although  not  perhaps  so  extensive  a  staple  as  the  cod-fishery, 
yet  when  capital  and  time  employed,  &c.,  are  taken  into  consideration,  it  is  the  most  profit- 
able business  of  that  colony,  or  perhaps  of  any  other  part  of  the  British  empire. 

A  quarter  of  a  century  ago,  there  were  only  about  50  vessels,  varying  from  30  to  60  tons 
burthen,  engaged  in  this  brancla  of  trade  ;  but  it  has  since  been  gradually  increasing.  In  the 
year  1850,  the  outfit  for  this  fishery  from  Newfoundland  consisted  of  229  vessels  of  20,581 
tons,  employing  7,919  men.  The  number  of  seals  taken  was  440,828.  According  to  the 
custom-house  returns  for  that  year,  the  total  value  of  skins  and  oils  produced  from  the  seal 
amounted  to  £298,796.  In  the  year  1852,  the  outfit  consisted  of  367  vessels  of  35,760 
tons,  employing  about  13,000  men.  There  were  from  half  to  three-quarters  of  a  miUion 
seals  captured. 

The  vessels  engaged  in  this  business  are  from  To  to  200  tons  burthen.  Those  lately 
added  to  the  sailing  fleet,  and  which  are  now  considered  of  the  most  suitable  sizes,  range 
from  130  to  160  tons.  Vessels  of  this  size  carry  from  40  to  50  men.  The  season  of  em- 
barking for  this  voyage  is  from  the  1st  to  the  15th  of  March.  The  voyage  seldom  exceeds 
two  months,  and  is  often  performed  in  two  or  three  weeks.  Several  vessels  make  two  voy- 
ages in  the  season,  and  some  perform  the  third  voyage  within  the  space  of  two  months  and 
a  half. 

The  seals  frequenting  the  coast  of  Newfoundland  are  supposed  to  whelp  their  young  in 
the  months  of  January  and  February ;  this  they  do  upon  pans  and  fields  of  ice,  on  the 
coast,  and  to  the  northward  of  Labrador.  This  ice — or  the  whelping-ice,  as  it  is  termed — 
from  the  currents  and  prevailing  northerly  und  north-east  winds,  trends  towards  the  east  and 
north-east  coast  of  Newfoundland,  and  is  always  to  be  found  on  some  part  of  the  coast  after 
the  middle  of  March,  before  which  time  the  seals  are  too  young  to  be  profitable. 

The  young  seal  does  not  take  to  the  water  until  it  is  three  months  old.  They  are  often 
discovered  in  such  numbers  within  a  day's  sail  of  the  port,  that  three  or  four  days  will  suf- 
fice to  load  a  vessel  with  the  pelts,  which  consist  of  the  skin  and  fat  attached,  this  being 
taken  off  while  the  animal  is  warm  ;  the  carcass,  being  of  no  value,  is  left  on  the  ice.  The 
young  seals  are  accompanied  by  the  old  ones,  who  take  to  the  water  on  the  approach  of 
danger.  When  the  ice  is  jammed,  and  there  is  no  open  water,  large  numbers  of  the  old 
seals  are  shot.  The  young  seals  are  easily  captured  ;  they  offer  no  resistance,  and  a  slight 
stroke  of  a  bat  on  the  head  readily  despatches  them.  When  the  pelts  are  taken  on  board, 
sufficient  time  is  allowed  for  them  to  cool  on  dock.  They  are  then  stowed  away  in  bulk  in 
the  hold,  and  in  this  state  they  reach  the  market  at  St.  John's  and  other  ports  in  the  island. 
Five-sevenths  of  the  whole  catch  reach  the  St.  John's  market.  A  thousand  seals  are  con- 
sidered as  a  remunerating  number  ;  but  the  majority  of  the  vessels  return  with  upwards  of 
3,000,  many  with  5,000  and  6,000,  and  some  with  as  many  as  7,000,  8,000,  and  9,000. 
Seals  were  formerly  sold  by  tale  ;  they  are  now  all  sold  by  weight — that  is,  so  nmch  per 
cwt.  for  fat  and  skin. 

The  principal  species  captured  are  the  hood  and  harp  seal.  The  bulk  of  the  catch  con- 
sists of  the  young  hood  and  harp  in  nearly  equal  proportions.  The  best  and  most  produc- 
tive seal  taken  is  the  young  harp.  There  are  generally  four  different  qualities  in  a  cargo 
of  seals,  namely,  the  young  harp,  young  hood,  old  harp  and  bedlamer,  (the  latter  is  the 
year-old  hood,)  and  the  old  hood.  There  is  a  difference  of  2s.  per  cwt.  in  the  value  of  each 
denomination. 

The  first  operation  after  landing  and  weighing  is  the  skinning,  or  separating  the  fat  from 
the  skin  ;  this  is  speedily  done,  for  an  expert  skinner  will  skin  from  300  to  400  young  pelts 
in  a  day.  After  being  dry -salted  in  bulk  for  about  a  month,  the  skins  are  sufficiently  cured 
for  shipment,  the  chief  market  for  them  being  Great  Britain.  The  fat  is  then  cut  up  and 
put  into  the  seal-vats. 

The  seal-vat  consists  of  what  arc  termed  the  crib  and  pan.  TIio  crib  is  a  strong  wooden 
erection,  from  20  to  30  feet  square,  and  20  to  25  feet  in  height.  It  is  firmly  secured  with 
iron  clamps,  and  the  interstices  between  the  upright  posts  are  filled  in  with  small  round 


830 


OILS. 


poles.  It  has  a  strong  timber  floor,  capable  of  sustaining  300  or  400  tons.  The  crib  stands 
in  a  strong  wooden  pan,  3  or  4  feet  hirger  than  the  square  of  the  crib,  so  as  to  catch  all  the 
drippings.  The  pan  is  about  3  feet  deep,  and  tightly  caulked.  A  small  quantity  of  water 
is  kept  on  the  bottom  of  the  pan,  for  the  double  purpose  of  saving  the  oil  in  case  of  a  leak, 
and  for  purifying  it  from  the  blood  and  any  other  animal  matter  of  superior  gravity.  The 
oil  made  by  this  process  is  all  cold-drawn ;  no  artificial  heat  is  applied  in  any  way,  which 
accounts  for  the  unpleasant  smell  of  seal  oil.  When  the  fats  begin  to  run,  the  oil  drops 
from  the  crib  upon  the  water  in  the  pan  ;  and  as  it  accumulates  it  is  casked  off,  and  ready 
for  shipment.  The  first  running,  which  is  caused  by  compression  from  its  own  weight,  be- 
gins about  the  10th  of  May,  and  will  continue  to  yield  what  is  termed  pale  seal  oil,  from 
two  to  three  months,  until  from  50  to  70  per  cent,  of  the  quantity  is  drawn  off',  according  to 
the  season,  or  in  proportion  to  the  quantity  of  old  seal  fat  being  put  into  the  vats.  From 
being  tougher,  this  is  not  acted  upon  by  compression,  nor  does  it  yield  its  oil  until  decom- 
position takes  place ;  and  hence  it  does  not,  by  this  process,  produce  pale  seal  oil.  The 
first  drawings  from  the  vats  are  much  freer  from  smell  than  the  latter.  As  decomposition 
takes  place,  the  color  changes  to  straw,  becoming  every  day,  as  the  season  advances,  darker 
and  darker,  and  stinking  worse  and  worse,  until  it  finally  runs  brown  oil.  As  this  running 
slackens,  it  then  becomes  necessary  to  turn  over  what  remains  in  the  vats.  The  crib  being 
generally  divided  into  nine  departments  or  pounds,  this  operation  is  performed  by  first 
emptying  one  of  the  pounds,  and  dispersing  the  contents  over  the  others,  and  then  filling 
and  emptying  them  alternately  until  the  entire  residue,  by  this  time  a  complete  mass  of 
putrefaction,  is  turned  over.  By  this  process  a  further  running  of  brown  oil  is  obtained. 
The  remains  are  then  finally  boiled  out  in  large  iron  pots,  which,  during  the  whole  season, 
are  kept  in  pretty  constant  requisition  for  boiling  out  the  cuttings  and  clippings  of  the  skin- 
ning and  other  parts  of  the  pelts,  which  it  is  not  found  advisable  to  put  into  the  vats.  The 
produce  of  this,  and  the  remains  of  the  vats,  are  what  is  termed  the  boiled  seal  oil.  These 
operations  occupy  about  six  mcniths,  and  terminate  towards  the  -end  of  September. 

During  the  montlis  of  July,  August,  and  September,  the  smell  and  effluvia  from  the  vats 
and  boiling  operation  are  almost  insufferable.  The  healthy  situation  of  St.  John's,  from  its 
proximity  to  the  sea,  and  the  high  and  frequent  local  winds,  is  doubtless  the  cause  of  pre- 
venting much  sickness  at  this  season  of  the  year.  The  men  more  immediately  employed 
about  the  seal-vats  have  a  healthy  and  vigorous  appearance. 

Some  improvement  has  taken  place  since  the  great  fire  of  1846,  when  all  the  seal-vats  in 
the  town  were  destroyed.  Many  of  the  manufacturers  have  erected  their  new  vats  on  the 
south  or  opposite  side  of  the  harbor-  but  there  still  remain  sufficient  vestiges  of  the  seal 
trade  to  cause  a  summer  residence  in  the  town  of  St.  John's  any  thing  but  desirable.  Even 
the  country  for  several  miles  around  St.  John's  affords  no  protection  from  these  horrible 
stenches.  The  animal  remains  from  the  vats,  and  the  oftal  from  the  cod-fi.sh,  arc  found  to 
be  such  a  valuable  manure,  that  they  are  readily  purchased  by  the  farmers  in  the  neighbor- 
hood ;  and  from  whatever  quarter  the  wind  blows,  the  pedestrian  in  his  rural  walk  has  little 
chance  of  breathing  a  genial  atmosphere. 

Mr.  S.  G.  Archibald  directed  his  attention  1o  some  mode  of  improving  the  manufiicture 
of  the  seal  oil.  The  result  of  several  experiments  upon  the  different  qualities  of  seal's  fat 
satisfied  him  that  the  whole  produce  of  the  fishery,  if  taken  while  the  material  is  fresh,  as 
it  generally  arrives  in  the  market,  and  subjected  to  a  process  of  artificial  heat,  was  capable 
of  yielding,  not  only  a  imiform  quality  of  oil,  but  the  oil  so  produced  was  much  better  in 
quality  than  the  best  prepared  by  the  old  process,  and  free  from  the  unpleasant  smell  com- 
mon to  all  seal  oil.  His  subsequent  experiments  resulted  in  the  invention  of  a  steam  appa- 
ratus for  rendering  seal  and  other  oils,  which  has  been  found  to  answer  an  admirable  pur- 
pose, and  for  which  he  received  letters-patent  under  the  Great  Seal  of  the  Island  of  New- 
foundland. 

The  advantage  of  this  processs  must  be  manifest,  when  it  is  understood  that  twelve  hours 
suffice  to  render  the  oil,  which  by  the  old  process  requires  about  six  months ;  that  a  uni- 
form quality  of  oil  is  produced  superior  to  the  best  pale  by  the  old  process,  and  free  from 
smell ;  that  a  considerable  percentage  is  saved  in  the  yield,  and  what  is  termed  pale  seal, 
produced  from  the  old  as  well  as  from  the  young  seal.  Besides,  if  this  process  were  uni- 
versally adopted,  the  manufacturing  season  would  cease  by  the  31st  of  May,  and  the  com- 
munity would  be  saved  from  the  annoyance  attending  the  old  process. 

The  chief  market  for  seal  oil  and  skins  has  hitherto  been  Great  Britain  and  Ireland  ;  a 
few  cargoes  occasionally  go  to  the  Continental  cities. 

In  the  United  States  the  great  consumption  of  oil  is  for  domestic  purposes.  Candles, 
unless  of  the  most  expensive  kind,  will  not  suit  that  climate,  particularly  in  the  summer 
season ;  and  hence  oil  and  camphene,  where  gas  is  not  used,  are  the  chief  ingredients  for 
lamps.  All  animal  oils  used  in  that  country,  whether  of  sperm,  right  whales,  or  lard,  arc 
rendered  by  artificial  heat,  and  in  consequence  free  from  the  unpleasant  smell  of  our  cold- 
drawn  seal  oil. 

Peir poise  Oil. — ^This  oil  very  much  resembles  whale  oil. 

Cod-liver  Oil. — This  oil  is  obtained  principally  from  the  livers  of  the  common  cod,  (C'al- 


OILS.  831 

lariax  ;  Gadus  Morrhua^)  previously  called  Af^selv.s  major,  and  also  from  some  allied  spe- 
cies, as  the  Dorse,  {Gadus  ca/larias,)  the  Coal  Fish,  {Merlangiis  carbonarlus,)  the  Burbot, 
{Lota  vidtjaris,)  the  Ling,  {Lota  molva,)  and  the  Torsk,  {Brosinnis  vulgaris.)  The  mode 
of  preparing  this  oil  varies  in  different  countries  ;  that  found  in  the  London  market  is  the 
produce  of  Newfoundland,  where,  according  to  Pennant,  it  is  thus  procured: — Some  spruce 
boughs  are  pressed  hard  down  into  a  half  tub,  having  a  hole  througli  the  bottom ;  upon 
these  the  livers  are  placed,  and  the  whole  exposed  to  the  sun.  As  the  livers  become  de- 
composed the  oil  runs  from  them,  and  is  caught  in  a  vessel  placed  under  the  tub. 

De  Jongh  describes  three  kinds  of  cod-liver  oil — the  pale,  pale  brown,  and  brown. 

Pale  Cod-liver  Oil. — This  is  golden-yellow  ;  without  disagreeable  odor  ;  not  bitter,  but 
leaves  a  peculiar  acrid,  fishy  taste  in  the  mouth  ;  has  a  slight  acid  reaction  ;  sp.  gr.  0-9'23  at 
63-5°  F.  Cold  alcohol  dissolves  from  2'5  to  2-7  per  cent,  of  the  oil ;  hot  alcohol  from  3-5 
to  4'5  per  cent.     It  is  soluble  in  ether  in  all  proportions. 

Pale  Brown  Cod-liver  Oil. — Color  of  Malaga  wine ;  odor  not  disagreeable ;  bitterish, 
leaving  an  acrid,  fishy  taste  in  the  throat ;  reacts  feebly  as  an  acid  ;  sp.  gr.  0  924  at  63'5° 
F,     A  little  more  soluble  in  alcohol  than  i\ie  pale  oil. 

Dark  Brown  Cod-liver  Oil. — This  is  dark  brown,  and  by  transmitted  light  is  greenish  ; 
it  possesses  a  disagreeable  odor,  bitter  and  empyreumatic  taste,  which  remains  some  time  in 
the  fauces  ;  it  is  slightly  acid  ;  sp.  gr.  0929  at  03-5"  F.  Still  more  soluble  in  alcohol  tiian 
the  pale  brown  oil. 

Cod-liver  oil  is  principally  used  in  medicine  ;  for  a  fuller  description  of  it,  see  Percira's 
Materia  Medica. 

Duffong  Oil. — ^This  oil  has  been  used  instead  of  cod-liver  oil,  principally  in  Australia ; 
but  as  very  little,  if  ani/,  real  Dugong  oil  has  reached  England,  it  will  merely  require  a 
short  notice  here.  The  Dugong  is  an  animal  belonging  to  the  class  of  herbivorous  cetacea, 
and  is  found  on  the  northern  coast  of  Australia,  in  the  Red  Sea,  the  Persian  Gulf,  and  also 
in  the  Indian  seas.  It  has  received  different  names  by  different  nations.  In  the  Indian 
seas  it  is  sometimes  found  of  a  large  size,  from  18  to  20  feet  long;  but  in  Australia  it  is 
seldom  caught  of  more  than  12  or  14  feet.  In  its  general  form  it  resembles  the  common 
whale.  Its  favorite  haunts  are  the  mouths  of  rivers  and  straits  between  proximate  islands, 
where  the  depth  of  water  is  but  trifling,  (3  or  4  fathoms,)  and  where,  at  the  bottom,  grows 
a  luxuriant  pasturage  of  submarine  algae  and  fuci,  on  which  it  feeds.  The  oil  is  obtained 
by  skinning  the  animal  and  then  boiling  down  the  "  speck."  It  was  used  by  the  natives  of 
Australia  originally  for  burning. 

Adulteration  of  the  Oih. — Owing  to  the  large  quantities  of  oil  of  various  kinds  which 
are  now  used,  and  their  difference  in  price,  many  are  the  adulterations  which  take  place. 
Thus  the  best  olive  oil  for  the  table  is  mixed  with  oils  of  less  value,  as  poppy  oil,  sesame 
oil,  or  ground-nut  oil ;  and  the  second  olive  oil,  for  the  manufacturers,  with  colza  oil  ;  and 
again  colza  oil  itself  mixed  with  poppy,  camelia,  and  linseed  oils,  but  more  frequently  with 
whale  oil,  &c.  Various  means  have  been  proposed  to  discover  these  admixtures.  M.  Le- 
febvre  proposed  to  take  advantage  of  the  difference  of  density  of  the  several  oils,  but  this 
is  a  very  insufficient  test,  as  many  of  the  oils  have  nearly  the  same  density. 

M.  Poutet  treats  the  oil  to  be  tested  with  one-twelfth  of  its  weight  of  a  solution  of 
nitrate  of  mercury,  containing  hyponitric  acid  ;  this  latter  substance  converts  the  olcine  of 
most  of  the  non-drying  oils  into  a  solid  substance,  elaidinc.  By  this  means  pure  olive  oil 
will  become  perfectly  solid  after  an  hour  or  two,  whereas  poppy  oil  and  the  drying  oils  in 
general  remain  perfectly  liquid ;  it  would  therefore  result  that  olive  oil,  adulterated  with 
tliesc  latter  oils,  would  be  prevented  from  solidifying  niore  or  less,  according  to  the  quantity 
of  these  oils  i)resent.  An  improvement  in  this  process  is  to  substitute  nitric  acid,  saturated 
with  hyponitric  acid,  for  the  nitrate  of  mercury  solution.  The  sample  to  be  tested  is  sha- 
ken with  two  or  three  per  cent,  of  this  acid,  and  then  placed  in  a  cool  place,  and  the  mo- 
ment of  solidification  noticed.  It  is  always  better  also  to  treat  a  samjile  of  oil  of  known 
purity  to  the  same  test  at  the  same  time,  and  com[)are  the  results.  If  the  sample  tested  l)e 
pure,  it  will  solidify  quite  as  quickly  as  the  sample  which  serves  for  coin|)arison.  One  hun- 
dredtli  of  poppy  oil  present  will  delay  the  solidification  40  minutes,  (Gerhardf,)  and  of 
course  the  greater  the  quantity  of  admixture,  the  irore  will  it  be  delayed. 

M.  Maumene  takes  advantage  of  the  greater  amount  of  heat  given  out  by  the  admixture 
of  concentrated  sulphuric  acid  witii  the  drying  oils,  than  takes  place  with  olive  oil  under  the 
same  circumstances.  Mil.  Ilcydcnreich  and  Penot  employ  sulphuric  acid  also  to  detect  the 
different  oils,  but  they  notice  the  peculiar  colorations  which  take  place  on  contact  of  the 
concentrated  acid  with  the  different  kinds  of  oils.  Their  test  is  thus  jierformed  : — One  drop 
of  concentrated  sulphuric  acid  is  added  to  8  or  10  drops  of  the  oil,  i>laced  on  a  piece  of 
wliite  gl.iss,  resting  on  a  sheet  of  wiiite  paper  ;  different  colorations  appear,  which  they  state 
are  characteristic  of  the  difl'erent  oils  ;  thus  olive  oil  gives  a  deep  yellow  tint,  becoming 
greenish  by  degrees;  colza  oil  a  greenish  blue  ;  I'oppv  oil,  a  pale  yellow  tint,  with  a  diily 
gray  outline  ;  hempseed  oil,  a  very  deej)  emerald  tint;  and  linseed  oil  liecomes  brownisli 
red,  passing  directly  into  blackish  brown,  <fcc.  These  reactions  are,  however,  uncertain  ;  the 
age  of  the  oil,  mode  of  extraction,  &c.,  altering  them  greatly. 


832 


OILS. 


Slarohand  states  that  a  mixture  of  poppy  oil  and  olive  oil,  when  thus  treated,  develop, 
after  a  certain  time,  on  their  outline,  a  series  of  colors,  rose,  lilac,  then  blue,  and  more  or 
less  violet-colored,  according  to  the  proportion  of  poppy  oil,  while  pure  olive  oil  becomes 
of  a  dirty  gray,  then  yellow  and  brown. 

As  the  means  of  detecting  the  various  fraudulent  admixtures  is  of  great  commercial 
value,  I  shall  conclude  by  giving  the  heads  of  F.  C.  Calvert's  valuable  paper  on  the  adulter- 
ation of  oils,  [Pharmaceutical  Journal,  xiii.  356.)  He  there  recommends  that  samples 
of  p7tre  oil  should  always  be  tested  comparatively  with  those  suspected  of  being  adulter- 
ated, and  never  to  rest  contented  with  only  one  of  the  tests  mentioned. 

As  the  reactions  presented  by  the  various  oils  depend  upon  the  special  strength  and 
purity  of  the  reagents,  not  only  should  great  care  be  taken  in  their  preparation,  but  also  in 
the  exact  mode  and  time  required  for  the  chemical  action  to  become  apparent.  These  points 
will  be  described  with  each  reagent. 

Solution  of  Caustic  Soda,  sp.  gr.  1'340. 
The  reactions  given  in  the  following  table  are  obtained  by  adding  one  volume  of  this 
test-liquor  to  five  volumes  of  oil,  well  mixing  them,  and  then  heating  the  mixture  to  its 
point  of  ebullition. 


Dark  Colorations. 

Light  Colorations. 

1  ish  Oils. 

Vegetable  Oils. 

Animal  Oils.            |                  Vegetable  Oils. 

Sperm  ) 
Seal       f       , 

Cod-  r'^- 

liver  ' 

L    thick 

Hempseed  -  brown- 

(  yellow. 

r-        A       S    fluid 
^^'^^^'^•i      iyellow. 

T.T     ,,        (  dirty  yel- 
Ne^»!-    .      lowish 
^°°t      (     white, 
y^    ,        ]   pinkish- 
^""'^    •  \     white. 

Pale  rapeseed     -^ 

FrSnut"        -Vtt'- 
Sesame      -        -3     ^'^''^• 
Castor       -         -[     „i,;x„ 
India-nut  (thick)  f     ^'^"^- 

8u'f" :    :]  ^'>-- 

The  principal  use  of  this  ta1)le  is  to  distinguish  fish  from  animal  and  vegetable  oils,  owing 
to  the  distinct  red  color  which  the  former  assume,  and  which  is  so  distinct  that  one  per  cent, 
of  fish  oil  can  be  detected  in  any  of  the  others.  Hempseed  oil  also  becomes  brown-yellow, 
and  so  thick  that  the  vessel  containing  it  may  be  inverted,  for  an  instant,  without  losing  any 
of  its  contents,  whilst  linseed  oil  acquires  a  much  brighter  yellow  color,  and  remains  fluid. 
India-nut  oil  is  characterized  by  giving  a  white  mass,  becoming  solid  in  five  minutes  after 
the  addition  of  the  alkali,  which  is  also  the  case  with  Gallipoli  and  pale  rape  oils,  while  the 
others  remain  fluid. 

The  next  test  he  uses  is  dilute  sulphuric  acid,  and  as  the  reactions  vary  with  the  strength 
of  the  acid,  he  employs  three  different  strengths. 

Sulphuric  Acid  of  sp.  gr.  1-475. 
The  mode  of  applying  this  acid  consists  in  agitating  one  volume  with  five  volumes  of 
oil  until  complete  admixture,  and  after  standing  fifteen  minutes  the  appearance  is  takon  as 
the  test  reaction. 


Not  Colored. 

Colored. 

Animal. 

Vegetable. 

Fish. 

Animal.          1                   Vegetable. 

Lard,  dirty. 

India-nut. 
Pale  rape- 
seed. 
Poppy. 
Castor. 

Sperm  )  light 
Seal      C  red. 
Cod-     [  pur- 
liver  )  pie. 

Neat's-  )  yellow 
•^oot   f  tinge. 

0]i.ve     -         -1 
G^Upoli         -f       f"'^"^ 
Sesame          -  [       *'"S^- 
Linseed          -         green. 

Hc,„psced     .]      '»«- 

French  nut    -      brownish. 

The  most  striking  reactions  in  this  table  are  those  presented  by  hempseed  and  linseed 
oils,  for  the  green  coloration  which  they  acquire  is  such,  that  if  they  were  used  to  adulte- 
rate any  of  the  other  oil.-<,  they  would  be  immediately  detected  if  only  present  to  the  amount 
of  ten  per  cent. 

The  red  color  assumed  by  the  fish  oils  with  this  test  is  also  sufficiently  marked  to  enable 
us  to  detect  them  in  the  proportion  of  one  part  in  100  of  any  other  oil,  and  it  is  at  the  point 
of  contact  of  oil  and  acid,  when  allowed  to  separate  by  standing,  that  the  red  color  is  prin- 
cipally to  be  noticed. 


OILS. 


833 


Sulphuric  acid,  sp.  gr.  1530. 
One  volume  of  this  acid  is  mixed,  as  before,  with  five  volumes  of  oil  and  allowed  to  stand 
five  minutes. 


Light  Colorations. 

Marked  Colorations. 

Animal. 

Vegetable. 

Fish. 

Vegetable. 

f""'  \     wLi.e. 

Olive 

Sesame 

India-nut 
Poppy  - 
Castor  - 
Pale  rapeseed 

greenish 

white. 

greenish 

dirty  white. 

■  dirty  white. 

pink. 

Gallipoli  •  1  intense 
French  nut  )    gray. 

(  intense 
Hempseed  \  green, 
Linseed    - 1     dirty 

(  green. 

As  hempseed,  linseed,  fish,  Gallipoli,  and  French  nut  oils  are  the  only  ones  that  assume 
with  the  above  reagent  a  decided  coloration,  they  can  be  discovered  in  any  of  the  others. 

Sulphuric  acid  of  sp.  gr.  1"635. 
This  acid  is  used  in  a  similar  manner  to  those  above,  and  the  coloration  noted  after  two 
minutes. 


Not  Colored. 

Distinctly  Colored. 

Vegetable. 

Fish. 

Animal. 

Vegetable. 

Poppy. 

Sesame. 

Castor. 

Sperm  \ 
Seal   -  f  intense 
Cod-     r  brown, 
liver  ; 

Olive  (light)        -        -  \ 
Hempseed  (intense)    -  >    green. 
Linseed       -         -         - ) 
Gallipoli     -        -        -  \ 
Pale  rapeseed     -         -  f    . 
French  nut          -         -  f   ^^"^"• 
India-nut  (light)          -  ) 

The  colorations  produced  by  sulphuric  acid,  sp.  gr.  1-635,  are  so  marked,  that  they 
may  be  consulted  with  great  advantage  in  many  cases  of  adulteration :  for  example,  Mr. 
Calvert  has  been  enabled  to  detect  distinctly  ten  per  cent,  of  rape-seed  in  olive  oil,  of  lard 
oil  in  poppy  oil,  of  French  nut  oil  in  olive  oil,  of  fish  oil  in  neat's-foot  oil. 

This  appears  to  be  the  maximum  strength  that  can  be  used,  for  nearly  all  the  oils  begin 
to  carbonize,  and  their  distinct  coloration  to  be  destroyed. 

Action  of  nitric  acid,  of  different  strengths,  on  oils : — 

Nitric  acid  of  sp.  gr.  1'180. 
One  part  of  this  acid,  by  measure,  is  agitated  with  five  parts  of  oil,  and  the  appearance, 
after  standing  five  minutes,  is  described  in  this  table. 


Not  Colored. 

Colored. 

Fish. 

Animal. 

Vegetable. 

Fish. 

Animal. 

Vegetable. 

Cod- 
liver. 

Lard. 

India-nut. 
Pale  rape- 
seed. 
Poppy. 
Castor. 

Seal    -     pink. 

Neat's- ('^;.^ 

Olive     -         -  )            .  , 
Gallipoli         .[greenish. 

Hempseed     -i      ^''^^ 
^               1     green,    j 

French  nut  -  )                  1 

Sesame             f        „         1 

/^...,„„«\      r    vcllow.  I 

(orange)   -  (     - 

Linseed         -  ; 

This  test  is  sufficiently  delicate  to  detect  distinctly  10  per  cent,  of  hempseed  oil  in  lin- 
seed oil,  as  the  mixture  assumes  the  greenish  hue  so  characteristic  of  the  former.  Althoujjh 
olive  acquires  a  greenish  color,  still  its  shade  is  such  that  it  is  entirely  distinguished  from 
that  of  hempseed. 

Nitric  acid  of  xp.  gr.  r220. 
The  proportion  of  acid  used,  and  the  time  of  contact  are  the  same  as  the  last. 
.  Vol.  in.— 53 


834 


OILS. 


Not  Colored. 

Colored. 

Fish. 

Animal. 

Vegetable. 

Fish. 

Animal. 

Vegetable. 

Cod- 
liver. 

Lard. 

India-nut. 
Pale  rape- 
seed,       j 

XT     .1      (  light 
Neat  s-  )    "  , 

'- 1  c. 

Poppy  (yel-     ) 

low)   -         .  1           . 
17        u       .      r      red. 
iTcncn  nut  -  ( 

Ses;ime          -  ) 

Olive    -         -  )             .  , 

GaUipoli        -  \  g-"^^"'^^- 

i  greenish 
Henipseed    -  -j      dirty 

(    brown. 
Linseed        -       yellow. 

The  chief  characters  in  the  above  table  are  those  presented  by  hempseed,  sesame,  French 
nut,  poppy,  and  seal  oils,  and  they  are  such  that  they' not  only  may  be  employed  to  distin- 
guish them  from  each  other,  but  are  sufficiently  delicate  to  detect  their  presence  when 
mixed  with  other  oils,  in  the  proportion  of  10  per  cent. 

Nitric  acid  of  sp.  fjr.  1'330. 
One  part  of  this  acid  is  mixed  with  5  parts  of  oil  by  measure,  and  remains  in  contact  5 
minutes. 


Not  Colored. 

Colored. 

Vegetable.    1 

Fish. 

Animal. 

Vegetable.                                1 

India  nut.  ; 
Pale  rape- 
seed. 
Castor. 

Sperm  ^ 
Seal   -  f       , 

Cod-  r'^- 

liver.  ) 

Neat's-  \  light 
foot    f  brown. 

i  very 
Lard  •<   slight 

(  yellow. 

Poppy 

French  nut (dark) 

Sesame  (dark) 

OHve  -        - 

Gallipoli 

Hempseed  - 
Linseed 

red. 

greenish. 

greenish 
dirty  brown, 
green,  becom- 
ing brown. 

The  colorations  here  described  are  very  marked,  and  can  be  employed  with  advantage 
to  discover  several  well-known  cases  of  adulteration :  for  instance,  if  10  per  cent,  of  sesame 
or  French  nut  oil  exists  in  olive  oil ;  but  the  same  proportion  of  poppy  oil  cannot  be  thus 
detected,  as  the  color  produced  is  not  so  intense  as  in  the  other  cases.  But  if  any  doubt 
remained  in  the  mind  of  the  operator,  as  to  whether  the  adultering  oil  was  sesame,  French 
nut,  or  poppy,  he  would  be  able  to  decide  it  by  applying  the  test  described  in  the  next  table, 
where  he  will  find  that  French  nut  oil  gives  a  fibrous  semi-saponified  mass,  sesame  a  fluid 
one,  with  a  red  liquor  beneath,  and  pippy,  also  a  fluid  mass,  but  floating  on  a  colorless 
liquid. 

The  successive  application  of  nitric  acid  of  sp.  gr.  1'330,  and  of  caustic  soda  of  sp.  gr. 
1'340,  can  be  also  successfully  applied  to  detect  the  following  very  frequent  cases  of  adul- 
teration ;  first,  that  of  Gallipoli  with  fi.sh  oils,  as  Gallipoli  oil  assumes  no  distinct  color  with 
the  acid,  and  gives  with  a  soda  a  mass  of  a  fibrous  consistency,  whilst  fish  oils  are  colored 
red,  and  becomes  mucilaginous  with  the  alkali. 

Secondly,  that  of  castor  oil  with  poppy  oil,  as  the  former  acquires  a  reddish  tinge,  and 
the  mass  with  the  alkali  loses  much  of  its  fibrous  appearance. 

Thirdly,  rapeseed  oil  with  French  nut  oil,  as  nitric  acid  imparts  to  the  former  a  more  or 
less  intense  red  tinge,  which  an  addition  of  the  alkali  increases,  and  renders  the  semi-sapon- 
ified mass  more  fibrous. 

Mr.  Calvert  here  remarks  that  the  coloration  which  divers  oils  assumes  under  the  influ- 
ence of  the  three  test  nitric  and  sulphuric  acids,  clearly  show  that  the  reason  why  chemists 
had  not  previously  arrived  at  satisfactory  results  in  distinguishing  oils  in  their  various  adul- 
terations, was  that  the  acids  they  employed  were  so  concentrated  that  all  the  distinctive 
colorations  were  lost ;  the  oils  became  yellow  or  orange ;  but  there  is  no  doubt  that  the 
above  reagent  will  enhance  the  value  of  Mr.  F.  Baudet's,  as  they  afibrd  very  useful  data  to 
specify  the  special  oils  mixed  with  olive  oil. 

Caustic  noda  of  up.  gr.  1"344. 
The  following  reactions  were  obtained  on  adding  10  volumes  of  this  test  liquor  to  the 
5  volumes  of  oil  which  had  just  been  acted  upon  by  1  part  of  nitric  acid: — 


OILS. 


835 


A  flbroua  mass  is  formed. 

A  fluid  mass  is  formed.                               | 

.\nimaL 

Vegetable. 

Fish. 

Animal. 

Vegetable. 

foot  }  '^^'^^- 

Gallipoli   ) 
India-nut  V  white. 
Castor    • ) 
French     ( ^, 

nut  -r^^- 

Hemp-      [    light 
seed    -  )  brown. 

Sperm. 
Seal. 
Cod- 
liver. 

Lard. 

S";«-        •        -        -[white. 
Pale  rapeseed      -         -  ) 

Linseed      -        -        '\£,^,^ 

Poppy  (light)      -        -       red. 

(  brown  ) 
Sesame        -  ■<   Uquor    V  amber. 

(  beneath  ) 

Having  given  in  a  previous  paragraph  some  of  the  most  useful  reactions  noted  in  this  table, 
attention  will  simply  be  called  to  the  following  mixtures :  neat's-foot  with  rape,  Gallipoli  with 
poppy,  castor  with  poppy,  hempseed  with  linseed,  sperm  with  French  nut,  and  Gallipoli 
with  French  nut.  It  is  necessary  also  here  to  mention  that  the  brown  liquor  on  which  the 
semi-saponified  mass  of  sesame  oil  swims,  is  a  very  delicate  and  characteristic  reaction. 

The  next  test  used  is  phosphoric  acid.  One  part  by  measure  of  syrupy  trihydrated  phos- 
phoric acid  is  agitated  with  5  parts  of  oil.  The  only  reaction  to  be  noticed  is  the  dark  red 
color,  rapidly  becoming  black,  which  phosphoric  acid  imparts  exclusively  to  the  fish  oils,  as 
it  enables  us  to  detect  1  part  of  these  oils  in  1,000  parts  of  any  other  animal  or  vegetable 
oils,  and  even  at  this  degree  of  dilution,  a  distinct  coloration  is  communicated  to  the  mixture. 
Mixture  of  sulphuric  and  nitric  acid. 

This  test  is  formed  of  equal  volumes  of  sulphuric  acid  of  sp.  gr.  1'845,  and  nitric  acid 
of  sp.  gr.  1-330,  and  is  thus  used  :  one  volume  of  this  mixture  is  mixed  with  5  volumes  of 
oil,  and  allowed  to  stand  2  minutes.  By  this  test  3  of  the  oils  remain  nearly  colorless,  viz., 
those  of  poppy,  olive,  and  India-nut,  while  all  the  others  become  brown,  except  sesame, 
hempseed,  and  linseed,  which  become  green,  turning  after,  sesame,  intense  red,  and  hemp- 
seed  and  linseed,  black.  .  „„^  „^  .„ 
'                                       A.qua  regia. 

This  test  is  composed  of  25  volumes  of  hydrochloride  acid  of  sp.  gr.  1-155,  and  1 
volume  of  nitric  acid  of  sp.  gr.  1-330,  and  allowed  to  stand  about  5  hours;  the  reactions  in 
the  following  table  are  those  which  take  place  when  a  mixture  of  5  volumes  of  oil  and  1  of 
the  aqua  regia  ie  agitated  and  allowed  to  stand  5  minutes. 


Not  Colored. 

Colored. 

Animal. 
Lard. 

Vegetable.    ' 

Fish. 

Animal. 

Vegetable. 

Olive.           1 

Sperm  (slight) 

I 

Neat's-  <    slight 
foot    (  yellow. 

French  nut    ^ 

Gallipoli.     ! 

Seal  (slight)    - 

•  yellow 

Sesame        -  {  ,.„,,„^ 
Linseed       .  h^How. 

India-nut.   ! 

Cod-liver 

Pale  rape- 

• 

(greenish)  ) 

seed. 

, 

Hempseed  -  greenish. 

Poppy. 

Castor. 

When  the  facts  contained  in  this  table  are  compared  with  the  preceding  ones,  we  are 
struck  with  their  uniformity,  and  are  led  to  infer  that  no  marked  action  had  taken  place  ; 
but  this  conclusion  is  erroneous,  as  most  of  them  assume  a  vivid  and  distinct  coloration  on 
the  addition  of  solution  of  soda  of  sp.  gr.  1-340,  as  seen  in  the  following  table  : — 


A  fibrous  mass  is  formed. 

1                        A  fluid  mass  is  formed. 

Animal. 

Vegetable.           • 

Fish. 

.\nimal. 
Lard, 

Vegetable. 

Neat's-  )  brownish 
foot   \    yellow. 

Gallipoli      ] 

1  Sperm  '\ 

Olive      -     white. 

(yellowish) 
India-nut 

y  white. 

1  Seal       {  orange- 
Cod-     t  yellow. 

pink. 

Poppy 

intense 
rose. 

Pale  rape- 

liver  ' 

orange 

seed  (yel- 
(lowish) 

Sesame - 

with 
brown 

Castor 

pale 
rose. 

liquor 
beneath. 

French  nut  -  orange. 

Linseed  -  orange. 

.Ho-P-dj,'*. 

83( 

2 

c 

e 

fe; 
to 

s 

} 

OILS. 

o 
o 

K 

a 

< 

Fold 
white  mass. 

Fil)rous 
yellowish- 

white  nias.s. 

Fibrous 
white  ma.ss. 

Fibrous 
yellowish- 
white  ma«s. 

Fluid 

intense  ro.se- 

colored 

mass. 

Fluid 
orange  mass 
with  brown 

liquor 

0            -^       • 

■fz  2  ?2  l^-'E-^-T-ll 

!||«ii|i||t 

mas.s. 

Fluid 
orange- 
yellow 

n  0  C 
=  PP 

•        • 

.       . 

0 

0 

P 

. 

Greei'. 

Greenish- 
yellow. 

Slight 
yellow. 

0 
P 

2,  ^ 

Orange- 
yellow. 
Dark 
brown. 

Orange- 
white. 
Dark 

brown. 

Slight 
yellow. 

1^" 

p£ 

tI-3 

C.S2 

2i5S 

.3 

'5-3 

Green 

beecuniug 

black. 

Ditto 

Brown. 

Dark 
brown. 

0 

c  c 

pp 

a     d    — 

.*   5   -• 

i;  «  O 

+       i 

i  ^ 

-  =S 

.       . 

B3>. 

• 

• 

Green. 

Brown 

yellow- 
green. 

■3 

3 
P 

0  c 

pp 

Fluid 

white  mass. 

Fibrous 

ditto. 

Ditto 
Fluid  ditto 

Light  red 
fluid  uuiss. 

if 

Fluid  red 

muss,  with 

brown 

liquor 

.a      5 

III 

Fibrous 
light  brown 
mass. 
Fluid 
yellow 
mass. 
Fluid  mass. 

Fibrous 
white  luass. 

1 

"3 
fa 

0  = 

1      S 

i    a 
o 

■3 

1 

0 
P 

• 

Greenish 
dirty 

brown. 

Green 
becoming 

brown. 
Very  slight 

yellow. 
Light 

brown. 

•3 

c  0 

pp 

<  - 

.2      o 

1     P 
O 

Orange- 
yellow. 

0 
P 

• 

Grepnish 

dirty 

brown. 

Yellow. 

Light 
yellow. 

P 

■3 

1. 

<    -• 

!2       o 

1  i 

•       •          • 

0  >• 

• 

Dirty 
greeii. 

Yellow. 

Light 
yellow. 

^1 

it 

^  rH  "■ 

■!■<£' 

•/I 

Light 
brown. 
Brown. 

d 

3 

• 

• 

Intense 
green. 

Green. 

Light 
brown. 
Browu. 

^  0 

0  £ 
PP 

a. 

(A 

Greeiiisli- 
white. 
Gray. 

Dirty 

white. 
rink. 

Dirty 
while. 

0 

33 

a.  ^ 

•3 

-3 

Intense 
green. 

Dirty 
green. 

Dirty 

Wllili!. 

Brownish 
(liny 
white. 

•6 

p| 

to 

~  <  -2 

to 

?  -J  o 

JI2 

■       • 

J3 

c 

2 

a 

11- 

a- 

• 

Intense 
green. 

Green. 

Dirty  white. 

Yellow 
tingo. 

1 

to 

P;? 

a.  _ 

-  s  o 

Thick  and 
white. 
Dirty 

yellowish- 
white. 
Ditto 

5 

3 
P 

i 

Thick 
brownish- 
yellow. 
Fluid 
yellow. 

Pinki.sh- 
wliite. 
Dirty 
yellowish- 
white. 

•3 
g 

CS 
P 

"55 
pp 

I 

Olivo 
Gallipoli-      •- 

India-nut 
Pale  rapesecd  • 

Poppy      -        -        - 

3 

s 
c 
b. 

0 

0 

CS 

0 

Ilempseed 

Linseed    - 

Lard        ... 
Noat's-foot 

s 

c. 

m 

1- 

Is 

OPEKAMETEE. 


The  effects  described  in  tliis  table  are  such  that  we  can  discover  with  facility  10  per 
cent,  of  a  given  oil  in  many  cases  of  adulteration  ;  lor  example,  poppy  in  rape,  olive  in 
(.JaUipoli  and  India-nut,  as  nil  of  them  assume  a  pale  rose  color;  but  wnen  poppy  is  mixed 
with  olive  or  castor  oils,  there  is  a  decrease  in  the  consistency  of  the  semi-saponitied  matter. 

By  the  aid  of  the  above  rea;;ents  we  can  also  ascertain  the  presence  of  U>  per  cent,  of 
French  nut  in  olive  or  linseed  oils,  as  the  semi-.saponified  ma.ss  becomes  the  more  fluid,  and 
the  presence  of  French  nut  in  pale  ra|)e,  (.iallipoli,  or  India-nut  oils,  is  recognized  in  con- 
se(|Uence  of  their  white  mass  accjuiring  an  orange  hue  ;  lin.seed  oil  is  delected  in  hempst'cd 
oil,  as  it  renders  the  fibrous  mass  ot  llie  latter  more  mucilaginous. 

Sesame  oil  also  gives  with  this  reagent  the  .same  reaction  as  with  nitric  acid  and  alkali, 
and  poppv  oil  is  distinguished  from  all  other  oils,  by  giving,  in  thi.s  case,  a  semi-sapouiiied 
mass  ol  a  bcautilul  rose  color. 

To  give  an  idea  how  the  above  tables  are  to  be  used,  Mr.  Calvert  suppo.^es  a  sample  of 
rapeseed  oil  adulteiated  witii  one  very  difficult  to  discover.  He  first  applies  the  caustic  alkali 
tost,  which,  on  giving  a  white  mas.s,  proves  the  alisence  of  the  fish  oils,  together  with  those 
of  hempseed  or  linseed  ;  and  as  no  distinct  reaction  is  produced  by  the  sami)le  of  oil  under 
examination  with  the  3  sulphuric  and  nitric  acids  above  mentioned,  poppy  and  sesame  oils 
aie  tlirown  out  as  they  are  reddened,  neatV-foot  oil,  India-nut,  castor,  olive,  and  l.ird  oils 
resting  only  in  the  .scale  of  probability.  In  order  to  discover  which  of  these  is  mixed  with 
the  suspected  oil,  a  ])ortion  of  it  is  agitated  first  with  nitric  acid  of  .sp.  gr.  r3(K»,  and  then 
with  c.iustic  .soda,  and  their  mutual  action  excludes  neat's-foot,  India-nut,  and  ca.stor  oils, 
as  the  sample  does  not  give  a  fluid  semi-saponified  mass.  The  absence  of  olive  oil  is  proved 
by  no  green  coloration  being  obtained  on  the  application  of  syrupy  phosphoric  acid.  As  to 
the  presence  of  lard  oil,  it  is  ascertained  on  c.iustic  soda  being  added  to  the  oil  which  has 
been  previously  acted  on  by  aqua  legia,  as  the  latter  gives  a  fibrous  yellowish  semi-saponi- 
fied mass,  whilst  the  former  yields  a  pink  fluid  one. 

In  order  to  facilitate  the  detection  of  any  adulteiation,  Mr.  Calvert,  gives  a  general  table 
of  the  preceding  reaction.s.     (See  table  on  preceding  page.) — H.  K.  B. 

OI'AL  maybe  regarded  as  an  uncleavable  quartz.  Its  fracture,  eonchoidal ;  lustre, 
vitreous  or  resinous ;  colors,  white,  yellow,  red,  brown,  green,  gray.  Lively  play  of  light ; 
hardness,  5'5  to  Co;  specific  gravity,  2  091.  It  occurs  in  small  kidney-shaped  and 
stalactitic  shapes,  and  huge  tuberose  concretions.  The  phenomena  of  the  play  of  colors  in 
precious  op.d  have  not  been  .satisfactorily  explained.  It  seems  to  be  connected  with  the 
regular  structure  of  the  mineral,  llauy  attributes  the  play  of  colors  to  the  fissures  of  the 
interior  being  filled  with  films  of  air  agreeably  with  the  law  of  Newton's  colored  rings. 
Moh^,  however,  thinks  this  would  produce  iridescence  merely.  Brewster  concludes  that  it  is 
o.ving  to  fi.ssures  and  cracks  in  the  interior  of  the  mass  of  a  uniform  shape.  It  is  said  that  the 
opal  wliich  grows  after  a  while  dull  and  opaque  may  be  restored  to  its  former  beauty  if  put 
for  a  short  time  in  water  or  oil.(?) 

The  precious  opal  stands  high  in  estimation,  and  is  considered  one  of  the  most  valuable 
gems,  the  size  and  beauty  of  the  stone  and  the  variety  of  the  colors  determining  its  value. 
The  so-called  "mountain  of  light,"  an  Hungarian  opal  in  the  Great  Exhibition  of  1851, 
weighed  52,U  carats,  and  was  estimated  at  £4,000  sterling. 

In  Vienna  is  a  precious  opal  weighing  17  oz.  ;  and  it  is  said  a  jeweller  of  Amsterdam 
olfered  iialf  a  million  of  florins  for  it,  which  was  refused. 

Hydrophane,  or  oculis  mundi,  is  a  variety  of  opal  without  transparency,  but  acquiring  it 
wjjen  immersed  in  water,  or  in  any  transparent  fluid.  Precious  opal  was  found  by  Kla[)rotli 
to  consist  of  silica,  90;  water,  10;  which  is  a  very  curious  combination.  Hungary  has  long 
been  the  only  locality  of  precious  opal,  where  it  occurs  near  Caschau,  along  with  common 
and  semi-opal,  in  a  kind  of  i)orphyry.  Fine  varieties  have,  however,  been  lately  discovered 
in  the  Faroe  islands;  and  most  beatiful  ones,  .sometimes  quite  transparent,  near  (iracios  h 
Dios,  in  the  province  of  Honduras,  Ameiica.  The  red  and  yellow  bright  colored  varieties 
of  (ire-opal  are  found  near  Zimapan,  in  Mexico.  Precious  opal,  when  fasiiioiied  lor  a  gem, 
is  generally  cut  with  a  convex  surface;  and  if  large,  pure,  and  exhii)itiiig  a  hiight  play  of 
colors,  is  of  considerable  value.  In  modern  times,  flue  opals  of  moderate  bulk  have  lieen 
fre(iuently  sold  at  the  price  of  diamonds  of  equal  size;  the  Tuiks  being  particularly  fond 
of  them.  The  estimation  in  which  opal  was  held  by  the  ancients  is  hardly  credible.  Nonius, 
the  Roman  senator,  preferred  banisiunent  to  parting  with  his  favorite  opal,  which  was 
coveted  by  Miirk  Antony  Opal  which  appears  quite  red  when  held  against  the  light,  is 
called  giraaol  by  the  French  ;  a  name  al.so  given  to  the  sapphire  or  corundum  asteria  or 
star-stone. 

OPERAMETER  is  the  name  givi'n  to  an  apparatus  invented  by  Samuel  AValkcr,  of 
Leeds.  Itconsistnof  a  train  ot  toothed  wheels  and  ])inionscnclo.sed  in  a  box,  having  indexes 
attached  to  the  central  arbor,  like  the  hands  of  a  clock,  and  a  dial  plate;  wT^ercljV  the  num- 
ber of  rotations  of  a  shaft  projecting  iiom  the  posterior  j)art  of  the  i)ox  is  shown.  If  this 
shaft  be  connected  Ijy  any  convenient  means  to  the  working  parts  of  a  gig,  mill,  shearing 
frame,  or  any  other  machinery  of  that  kind  for  dressing  cloths,  the  number  of  rotations  made 


OPIUM. 


by  the  operating  macbine  will  be  exhibited   by  the  indexes  upon  the  dial  plate  of  this 
apparatus. 

A  similar  clock-work  mechanism,  called  a  couyiter,  has  been  for  a  great  many  years 
employed  in  the  cotton  factories  and  in  the  pumping  engines  of  the  Cornish  and  other 
mines,  to  indicate  the  number  of  revolutions  of  the  main  shaft  of  the  mill  or  of  the  strokes  of 
the  piston.  A  common  pendulum  or  spring-clock  is  commonly  set  up  alongside  of  the 
counter;  and  sometimes  the  indexes  of  both  are  regulated  to  go  together. 

OPIUM  is  the  juice  which  exudes  from  incisions  made  in  the  heads  of  ripe  poppies, 
(Papaver  Komni/rnDii,)  Tcndi^'red  concrete  by  exposure  to  the  air.  The  best  opium  which 
is  found  in  the  European  markets  comes  from  Asia  Minor  and  Egypt ;  what  is  imported 
from  India  is  reckoned  inferior  in  quality.  This  is  the  most  valuable  of  all  the  vegetable 
products  of  the  gum-resin  family,  and  very  remarkable  for  the  complexity  of  its  chemical 
composition. 

ORCHELLE  WEEDS.  The  cylindrical  and  flat  species  of  Roccella  used  in  the  manu- 
facture of  Orchil  and  Cudbear,  are  so  cdled  by  the  makers. 

Dr.  Pereira  says  Mr.  Harman  Visger,  of  Bristol,  "  informs  me  that  every  lichen  but  the 
best  orchella  weed  is  gone,  or  rapidly  going  out  of  use,  not  from  deterioration  of  their 
quality,  for,  being  allowed  to  grow,  they  are  finer  than  ever ;  but  because  the  Angola  weed 
is  so  superior  in  quality,  and  so  low  priced  and  abundant,  that  the  product  of  a  very  few 
other  lichens  would  pay  the  expense  of  manufacture."  In  the  Ffii/osopliical  Transactions 
for  1848,  Dr.  Stenhouse  has  a  valuable  paper  on  the  coloring  matters  of  the  lichens.  From 
it  we  extract  his  directions  for  estimating  the  coloring  matter  in  lichens  by  means  of  a 
solution  of  hypochlorite  of  lime. 

Any  convenient  quantity  of  the  orchelle  weed  may  be  cut  into  very  small  pieces,  and 
then  macerated  with  milk  of  lime,  till  the  coloring  matter  is  extracted.  Three  or  four 
macerations  are  quite  sufficient  for  this  purpose,  if  the  lichen  has  been  sufficiently  com- 
minuted. The  clear  liquors  should  be  filtered  and  mixed  together.  A  solution  of  bleach- 
ing powder  of  known  strength  should  then  be  poured  into  the  lime  solution  from  a 
graduated  alkalimeter.  The  moment  the  bleaching  liquor  comes  in  contact  with  the  lime 
solution  of  the  lichen,  a  blood-red  color  is  produced,  which  disappears  in  a  minute  or  two, 
and  the  liquid  has  only  a  deep  yellow  color.  A  new  quantity  of  the  bleaching  licjuid  should 
then  be  poured  into  the  lime  solution,  and  the  mixture  carefully  stirred.  This  operation 
should  be  repeated  so  long  as  the  addition  of  the  hypochlorite  of  lime  causes  the  production 
of  the  red  color,  for  this  shows  that  the  lime  solution  still  contains  unoxidizcd  colorific 
principle.  Towards  the  end  of  the  process,  the  bleaching  solution  should  be  added  by  only 
a  few  drops  at  a  time,  the  mixtuie  being  carefully  stirred  between  each  addition.  We  have 
only  to  note  how  many  measures  of  the  bleaching  liquid  have  been  required  to  destroy  the 
coloring  matter  in  the  solution,  to  determine  the  amount  of  the  colorific  principle  it  contain- 
ed. Dr.  Stenhouse  suggests  the  following  method  for  extracting  the  colorific  principle  for 
transport: — Cut  the  lichens  into  small  pieces,  macerate  them  in  wooden  vats  with  milk  of 
lime,  and  saturate  the  solution  with  either  muriatic  or  acetic  acid.  The  gelatinous  principle 
is  then  to  be  collected  on  cloths  and  dried  by  a  gentle  heat.  In  this  way  the  whole  of  the 
heat  can  be  easily  extracted,  and  the  dried  extract  transported  from  the  most  distant 
localities. 

ORES,  DRESSING  OF.  In  metalliferous  veins  the  deposits  of  ore  are  extremely  ir- 
rc'iular  and  much  intermixed  with  gangue  or  vein  stone.  In  excavating  the  lode,  it  is 
usual  for  the  miner  to  effect  a  partial  separation  of  the  valuable  from  the  worthless  porticfti ; 
the  former  he  tempoiarily  stows  away  in  some  open  place  imdcrground,  whilst  the  latter  is 
cither  employed  to  fill  up  useless  excavations,  or  in  due  course  sent  to  surface  to  be  lodged 
on  the  waste  heaps.  From  time  to  time  tlie  valuable  part  of  the  lode  is  drawn  to  the  top 
of  the  shaft,  and  from  thence  conveyed  to  the  dressing  floors,  where  it  has  to  be  prepared 
for  metallurgic  treatment. 

This  process  is  known  as  dressing,  and  in  the  majority  of  instances  includes  a  series  of 
operations.  In  this  country  it  is  chiefly  restricted  to  mechanical  treatment,  the  chemical 
manipulation  being  performed  by  the  .smelter.  Hand  labor,  picking,  washing,  sizing,  and 
reducing  machinery,  together  witii  water-concentrating  apparatus,  comprise  the  usual  re- 
sources of  the  dresser,  but  sometimes  he  may  find  it  useful  to  have  recourse  to  the  furnace, 
since  it  may  happen  that  by  slightly  changing  the  chemical  state  of  the  substances  that 
compose  the  ore,  the  earthy  jiarts  may  become  more  easily  separable,  as  also  the  other 
foreign  matters.  Willi  this  view,  the  ores  of  tin  are  often  calcined,  which,  by  separating 
the  arsenic  and  oxidizing  the  iron  and  copper,  furnishes  the  means  of  obtaining,  by  the 
subsequent  washing,  an  oxide  of  tin  much  purer  than  could  be  otherwise  procured.  In 
general,  however,  these  are  rare  cases ;  so  that  the  washing  almost  afways  immediately 
succeeds  the  f)icking,  crushing,  or  stamping  processes. 

Before  entering  u|)on  the  description  of  machinery  employed  in  the  concentration  of 
ores,  it  i.-<  impartant  to  notice  the  principles  upon  which  the  various  mechanical  operations 
are  based. 


ORES,  DKESSING  OF.  839 

If  bodies  of  various  sizes,  forms,  and  densities  be  allowed  to  fall  into  a  liquid,  in  a  state 
of  rest,  the  amount  of  resistance  wliich  lliey  experience  will  be  very  unequal,  and  conse- 
quently they  will  not  arrive  at  the  bottom  at  tlie  same  time.  This  necessarily  produces  a 
sort  of  classification  of  the  fraj^mcnts,  which  becomes  apparent  on  examining  the  order  in 
which  they  have  been  deposited. 

If  it  be  supposed  that  the  substances  have  similar  foDus  and  dimensions,  and  d'^er  from 
each  other  in  deusili/  only,  and  it  is  known  that  the  resistance  which  a  body  will  experience 
in  moving  through  a  liquid  medium  depends  solely  on  its  form  and  extent  of  surfaces,  and 
not  on  its  specific  gravity,  it  follows  that  all  substances  will  lose  under  similar  circumstances 
an  equal  amount  of  moving  force. 

Tills  loss  is  proportionally  greater  on  light  bodies  than  in  those  having  more  consider- 
able density.  The  former  for  this  reason  fall  through  the  liciuid  with  less  rapidity  than  the 
denser  fragments,  and  must  therefore  arrive  later  at  the  bottom,  so  that  the  deposit  will  be 
constituted  of  diH'ercnt  strata,  arranged  in  direct  relation  to  their  various  densities,  the 
heaviest  being  at  the  bottom,  and  the  lightest  at  the  top  of  the  series. 

Supposing,  on  the  contrary,  that  all  the  bodies  which  fall  through  the  water  possess 
similar  forms  and  equal  specific  gravities,  and  that  they  only  differ  from  each  other  in  point 
of  volume,  it  is  evident  that  the  rapidity  of  motion  will  be  in  proportion  to  their  sizes,  and 
the  larger  fragments  will  be  deposited  at  the  bottom  of  the  vessel. 

As  the  bodies  on  starting  are  supposed  to  have  the  same  forms  and  densities,  it  follows 
that  the  resistance  they  experience  whilst  descending  through  water  will  be  in  'proportion 
to  the  surface  exposed,  and  as  the  volumes  of  bodies  very  according  to  the  cubes  of  their 
corresponding  dimensions,  whilst  the  surfaces  only  vary  in  accordance  with  the  squares  of 
the  same  measurements,  it  will  be  seen  that  the  force  of  movement  animating  them  is 
regulated  hi/  their  cubes  whilst  their  resistance  is  in  proportion  to  their  squares. 

If,  lastly,  it  be  imagined  that  all  the  fragments  have  the  same  volume  and  density  but 
are  of  various  forms,  it  follows  that  those  possessing  the  largest  amount  of  surface  will 
arrive  at  tlie  bottom  last,  and  consequently  the  upper  part  of  the  deposit  will  consist  of  the 
thinnest  pieces. 

It  is  evidently  then  of  the  greatest  importance  that  the  grains  of  ore  which  are  to  I)e 
concentrated  by  washing  should  be  as  nearly  as  possible  of  the  same  size,  or  otherwise  the 
smaller  surface  of  one  fragment,  in  proportion  to  its  weight,  will  in  a  measure  compensate 
for  the  greater  density  of  another,  and  thus  cause  it  to  assume  a  position  in  the  series  to 
which  by  its  constitution  it  is  not  entitled. 

This  difficulty  is  constantly  found  to  occur  in  practice,  and,  in  order  as  much  as  possiVjle 
to  obviate  it,  care  is  taken  to  separate  by  the  u.se  of  sieves  and  trommels  into  distinct 
parcels,  the  fragments  which  have  respectively  nearly  the  same  size.  Although  by  this 
means  the  grains  of  ore  may  to  a  certain  extent  be  classified  according  to  their  regular 
dimensions,  it  is  impossible  by  any  mechanical  contrivance  to  regulate  their  forms,  which 
must  greatly  depend  on  the  natural  cleavages  of  the  substances  operated  on,  and  hence  this 
circumstance  must  always  in  some  degree  affect  the  results  obtained. 

Each  of  the  broken  fragments  of  ore  must  necessarily  belong  to  one  of  the  three  follow- 
ing classes: — the ^rv<  class  consists  of  those  which  are  composed  of  the  mineral  sought 
without  admixture  of  earthy  matter.  The  second  will  comprehend  the  fragments  which  are 
made  up  of  a  mixture  of  mineral  ore  and  earthy  substances,  whilst  the  //nrJ  division  may 
be  wholly  composed  of  earthy  gangue  without  the  presence  of  metallic  ore.  By  a  success- 
ful washing  these  three  classes  should  be  sejjarated  from  each  other. 

The  most  difficult  and  expensive  vein  stuff  for  the  dressing  floors  is  that  in  which  the 
constituents  have  nearly  an  uniform  aggregation,  and  where  the  specific  gravity  of  the 
several  substances  approximate  closely  to  c6,ch  other.  In  such  case  the  ore  is  only  sep- 
arated from  the  waste  after  much  care  and  labor,  and  often  at  the  loss  of  a  considerable 
portion  of  the  ore  itself  When,  however,  the  ore  is  massive  and  distinct  from  the  gangue, 
and  the  specific  gravity  of  the  latter  much  less  than  the  former,  then  the  operation  of  clean- 
ing is  usually  very  simple,  effected  cheaply,  and  with  but  little  loss  on  the  ore  originally 
present. 

The  losses  which  may  be  sustained  in  the  manipulation  and  enrichment  of  ores  is  a 
matter  of  great  importance,  and  demands  not  oidy  direct  attention  from  the  chief  agent, 
but  also  calls  for  the  constant  vigilance  of  the  dresser.  No  one  can  approve  of  a  system 
which  omits  to  record  the  initial  (piantity  of  ore  brought  to  the  surface,  noting  only  the 
tonnage  and  percentage  of  the  parcel  jiroduced  for  sampling. 

Yet  such  inattention  jirevails  generally  in  the  mining  districts  of  this  country.  What 
would  be  thought  of  a  smelter  who  might  systematically  purchase  and  receive  ores  without 
ascertaining  their  produce,  and  reduce  them  in  furnaces  totally  unfitted  (or  the  purpose, 
without  regarding  the  losses  which  might  be  sustained  ?  If  he  became  insolvent  it  would 
excite  no  surprise,  l»ut,  on  the  contrary,  the  public  would  most  likely  loolv  upon  his  position 
as  the  inevitable  lesult  of  a  defective  and  reprehensible  mode  of  working. 

It  will  be  admitted  that  mineral  exploitatioiid  are  of  a  highly  hazardous  nature,  and 


840 


ORES,  DRESSING  OF. 


Assayed 

1770 


that  the  risk  of  profit  ought  not  to  be  increased  either  by  ignorance  or  capclossness.  "When 
ores  are  discovered,  usually  after  the  expenditure  of  much  money,  a  certain  amount  of 
productive  and  dead  cost  is  incurred  before  they  can  be  rendered  at  the  dressing  floors;  if 
then  the  least  waste  takes  place  there  is  not  only  a  loss  per  ne,  but  the  mine  expenditure  is 
augmented  upon  the  lessened  quantity,  hence  in  no  department  of  mining  economics  is  it 
more  essential  to  secure  higher  practical  talent  than  in  the  dressing  and  management  of 
vein  stuff.  The  individual  entrusted  with  this  duty  should  be  competent  to  assay  the  ores, 
have  a  knowledge  of  the  losses  resulting  from  their  metallurgic  treatment,  and  know 
ajiproximately  the  cost  of  enriching  them  on  the  floors  as  well  as  of  smelting  them  ;  he  will 
then  conduct  his  operations  so  that  the  cost  and  loss  iu  dressing  will  be  less  than  the  cost 
and  loss  in  smelting. 

Some  of  the  more  friable  ores,  when  simply  exposed  to  the  influence  of  water,  exhibit 
a  large  mechanical  loss,  so  much  so,  that  it  is  considered  oftentimes  more  profitable  to 
put  them  to  pile  without  attempting  their  enrichment.  Now  it  may  be  laid  down  as  an 
axiom  that  water  will  always  steal  ore,  and  the  longer  it  is  exposed  to  its  influence,  and  the 
more  complicated  the  manipulation,  the  greater  will  be  the  loss  incurred.  In  addition,  the 
constitution  of  certain  ores  is  .so  peculiar  and  delicate,  that  any  attempt  to  concentrate  tl;em 
beyond  a  given  standard,  by  varying  the  treatment,  is  seen  to  lead  to  an  enormous  loss,  as 
will  be  apparent  by  inspecting  the  following  memoranda  of  practical  results:  — 

(A.)—The  ore  operated  upon  was  sulphide  of  lead,  associated  with  finely  disseminated 
iron  pyrites,  oxide  of  iron,  quartz,  and  a  small  portion  of  clay  slate.  In  each  case  the  vein 
stuff  assayed  17  per  cent,  of  metal. 

Quantity  Quantity 

by  weiglit.  by  wtight 

1     washed  and  concentrated  to  "io  ^  T  fil  per  cent. 

1  "  "  -40  S9 

1     burnt,  roasted,  and  do.  '20       The  loss  on  metal       57         " 

2'4  washed  aud  do.  "43       originally  present       37^       " 

■{    1-56  y  in  the  ore  by  vary    •■ 

20        loss  by  roasting  ing  the  mechani- 

— 1-36  washed  and  concentrated  to '40       cal  treatment  was       50         " 
■8  roasted,  washed,  do.  -42  33         " 

■8         "  "  -69  J  [  16|       " 

(B.) — Took  two  parcels  of  argentiferous  lead  ore,  associated  with  carbonate  of  iron,  a 
little  quartz,  and  blende.  Weight  'ii'-^u  tons,  which  assayed  42i  percent,  for  lead,  and 
29  oz.  of  silver  per  ton  of  metal.  Crushed  and  carefully  elaborated  the  same  through  jig- 
ging and  buddle  apparatus,  obtained  14 '%o  tons  of  ore,  giving  54^  per  cent,  for  lead,  and 
22  ounces  of  silver  per  ton  of  metal.  The  produce  for  lead  was  therefore  raised  12  units 
at  a  loss  of  49  per  cent,  of  the  initial  quantity  of  metal  and  95  ounces  of  silver.  The  com- 
mercial loss  attending  this  operation,  after  making  the  several  charges  and  allowances 
incident  to  the  metallurgic  reduction,  was  £91  14s.,  or  equal  to  £2  14s.  per  ton  on  the 
original  weight. 

Additional  instances  of  heavy  losses  incurred  in  the  concentrating  process  could  be 
adduced  if  space  permitted ;  but  it  may  not  be  unwise  to  direct  special  attention  to  the 
great  waste  often  connected  with  the  manipulation  of  both  tin  and  argentiferous  ores.  In 
the  former  it  occurs  chiefly  from  the  o.\ide  of  tin  being  much  diffused  through  hard  vein 
stone,  requiring  seveic  mechanical  treatment  in  order  to  liberate  it,  whilst  in  the  latter  the 
silver  (not  unfrcquently  combined  mechanically),  imperceptible  to  the  eye,  floating  away 
when  subjected  to  water,  and  so  subtle  as  to  evade  the  most  delicately  devised  apparatus. 
Tlie  loss  accruing  in  one  large  undertaking  from  this  source  alone  upon  1,100  tons  of  ore 
was  3,026  ounces  of  silver  worth  £830,  or  equal  to  the  interest  on  £16,600,  at  the  rate  of 
5  per  cent   per  annum. 

In  order  to  determine  the  loss  of  metal  which  may  arise  in  enriching  ores,  accurate 
assays  and  notations  should  be  made  of  the  quantity  of  vein  stuff  lodged  on  the  floors,  which 
should  be  compared  with  the  metallic  contents  rendered  merchantable,  and  the  difl'erences 
estimated. 

It  is  not  possible  to  ascertain  the  value  of  an  improvement  which  would  secure  an 
additional  one  per  cent,  from  the  quantity  of  orey  stuff  annually  sent  to  surface  from  the 
several  mines  in  the  United  Kingdom  ;  but  if  it  be  reckoned  only  upon  the  sale  value  it 
would  be  scarcely  less  than  £40,000  per  annum. 

In  determining  the  site  for  a  dressing  floor,  and  in  making  the  mechanical  arrangements, 
various  points  suggest  themselves  ;  since,  if  they  were  overlooked,  much  loss  would  ensue 
to  the  undertaking,  or  otherwise  it  is  evident  that  they  could  only  be  corrected  by  involving 
the  proprietary  in  an  increased  outlay  as  well  as  a  greater  current  expenditure.  The  first 
consideration  should  be  to  secure  an  ample  supjily  of  water,  with  a  good  fall,  and  an  ex- 
tensive area  of  ground.  With  advantages  of  this  nature  the  machinery  will  be  worked 
cheaply,  the  stud'  gravitate  through  the  various  processes  without  returning  to  create  double 


OHES,  DKES6ING  OK 


841 


carriage  expenses,  whilst  the  castaways  may  be  sent  to  the  waste  heaps  at  a  minimum  cost. 
Tlie  second  point  to  be  settled,  is  the  class  of  machinery  to  be  employed.  This  must  ob- 
viously be  based  upon  the  character  which  the  ores  may  present.  If  massive,  and  associated 
with  light  waste,  simple  apparatus  will  suffice ;  but  if  the  ore  be  sparsely  diffused  among 
heavy  vein  stone,  it  is  probable  that  the  various  apparatus  will  have  to  be  constructed  with 
great  nicety,  varied  in  their  principles  of  action,  and  that  much  precaution  will  have  to  be 
observed  in  order  to  create  as  little  slime  as  possible,  as  well  as  to  secure  the  initial 
([uantity  of  ore  against  undue  loss.  In  the  disposition  of  the  machinery  there  is  also  consider- 
able scope  for  practical  intelligence ;  it  is  not  enough  to  wash,  crush,  jig,  and  buddle  the 
ores,  mi.xing  the  resulting  smalls  incongruously  together;  but  a  judicious  sorting  should  be 
commenced  at  the  wash  kilns,  and  upon  this  basis  the  various  sizes  kept  distinct  whilst 
passing  through  the  washing  floors.  The  dresser  should  also  take  care  to  keep  the  several 
ranges  of  mineral  produces  and  degrees  of  fineness  together. 

The  following  general  deductions  will  be  found  serviceable  : — 

First. — Absolute  perfection  in  separation  according  to  specific  gravity  cannot  be  arrived 
at,  chiefly  on  account  of  the  irregularity  of  form  of  the  various  grains  to  be  operated  upon. 

Second. — The  more  finely  divided  the  stuff  to  be  treated,  the  greater  is  the  amount  of 
labor  and  care  required,  and  the  more  imperfect  will  be  the  separation. 

Third. — That  reducing  machine  maybe  considered  the  most  perfect  which  produces  the 
least  quantity  of  stuff  finer  than  that  which  it  is  intended  to  produce. 

Fourth. — It  is  necessary,  in  determining  the  degree  of  fineness  to  which  a  mineral 
should  be  reduced,  to  consider  the  metallurgic  value  of  the  ore  contained  in  it,  and  to  set 
against  this  the  value  of  the  loss  which  will  probably  be  incurred,  together  with  the  labor 
and  expense  attendant  upon  the  manipulation. 

Fifth. — The  vein  stuff  should  be  reduced  to  such  a  degree  of  fineness  that  the  largest 
proportion  of  deads  and  clean  ore  should  be  obtained  by  the  first  operation,  thus  saving 
the  labor  and  preventing  the  loss  incident  to  a  finer  subdivision  of  the  ore  and  more 
extended  treatment. 

Sixth. — That  apparatus  or  plan  of  dressing  may  be  considered  the  most  efficient 
which  with  stuff  of  a  given  size  allows  at  an  equal  cost  of  the  most  perfect  separation,  and 
of  the  proper  separation  of  stuff  of  nearly  equal  specific  gravity. 

The  average  percentage  to  which  the  crop  is  to  be  brought,  and  the  highest  percentage 
to  be  allowed  in  the  castaways  being  determined,  it  is  evident  that  the  more  perfect  the 
degree  of  separation  the  greater  will  be  the  amount  of  crop  and  castaways  obtained  at  each 
operation,  and  the  quantity  of  middles  or  stuff  to  be  re-worked  will  be  diminished. 

Seventh. — We  may  further  consider  as  a  great  improvement  in  dressing  operations  such 
apparatus  or  plan  of  working  as  will  allow,  without  a  disproportionate  increase  in  the  cost, 
of  the  equally  perfect  separation  of  fine  stuff  as  that  of  the  coarser,  as  now  practised  This 
will  be  of  especial  benefit  in  the  ca.se  of  finely  disseminated  ore,  which  is  necessarily  obliged 
to  be  reduced  to  a  great  degree  of  fineness. 

Washing  and  Separating  Oues. 

The  vein  stuff,  on  arriving  at  the  surface,  is  not  onlj'  associated  with  a  large  amount  of 
gangue,  but  is  frequently  much  intermixed  with  clay,  rock,  and  siliceous  matter. 

In  order  to  get  rid  of  the  latter  substances,  it  is  usually  washed  and  picked.  The  wash- 
ing apparatus  ought  to  be  so  contrived  as  to  allow  the  cleansing  to  be  effected  both  cheaply 
and  expeditiously,  and  for  this  purpose  a  good  volume  of  water  is  always  desirable.  If  a 
height  or  fall  can  be  obtained,  it  will  also  be  found  advantageous.  In  accordance  with  the 
character  of  the  ore  the  apparatus  will  have  to  be  varied ;  but  for  lead,  certain  varieties  of 
copper  ore,  as  well  as  iron,  or  other  abundant  ores,  the  kiln  is  well  adapted.  In  many 
mines  rectangular  grates  are  fitted  to  the  bottom  of  the  kilns,  but  a  perforated  plate  would 
b(!  found  to  furni.sh  better  results,  since  the  former  allows  of  the  passage  of  flat  irregular 
masses  of  stone,  rendering  the  treatment  in  the  jigging  sieves  less  successful.  The  holes  in 
tlic  perforated  plate  should  be  conical,  the  largest  diameter  underneath,  so  that  the  stones 
may  have  unobstructed  passage.  In  connection  with  the  kiln-plate  a  sizing  trommel  should 
l)(!  used,  and  in  order  to  economize  both  time  and  expenditure  it  would  be  judicious  to 
introduce  the  vein  stuff,  and  discharge  the  castaways  by  means  of  railways. 

The  picking  of  the  stuff  is  a  highly  important  operation.  As  a  rule  all  picked  ore 
should  be  selected,  and  the  dradge  (lei)iived  of  the  largest  possible  amount  of  waste  before 
it  is  sent  to  the  crusher.  It  is  highly  fallacious  to  suppose,  because  machinery  will  deal 
with  large  quantities  expcMlitiously,  that  it  is  cheaper  to  subject  the  mass  to  its  action  ;  on 
the  contrary,  if  correct  calculations  are  made  of  the  losses  which  will  ensue  on  the  initial 
<iuantity  of  ore  before  the  residue  is  ready  for  the  pile,  the  cost  of  the  several  intricate 
manipulations  rocjuisite  to  get  rid  of  the  castaways,  the  wear,  fear,  and  maintenance  of 
machinery,  it  will  api)ear  in  the  majority  of  ca.ses  that  the  most  profitable  method  is  to 
incur  an  extra  first  charge  in  order  to  reject  the  sterile  portions  by  means  of  hand  labor. 
The  ragging  hammer  shoidd  tliercfore  be  brought  into  free  reciuisition,  and  all  worthless 
^  uios  at  once  rejected  ;  then  in  spalling  such  portions  as  have  been  ragged  an  additional 


842 


OKES,  DRESSING  OF. 


quantity  of  refuse  should  be  excluded,  whilst  in  the  process  of  cobbing  either  ragged  or 
spalled  work,  the  greatest  care  and  attention  should  be  given  in  order  to  bring  the  dradge 
to  a  maximum  degree  of  richness. 

Among  the  sittings  and  washings  which  ores  are  made  to  undergo,  we  would  notice 
those  practised  on  the  Continent,  grilles  anglaises,  and  step-ivashinys  of  Hungary,  lavcries 
a  r/radins.  These  methods  of  freeing  the  ores  from  pulverulent  matters,  consist  in  placing 
them,  at  their  out-put  from  the  mine,  upon  gratings,  and  bringing  over  them  a  stream  of 
water,  which  merely  takes  down  through  the  bars  the  small  fragments,  but  carries  off  the 
finer  portions.  The  latter  are  received  in  cisterns,  where  they  are  allowed  to  rest  long 
enough  to  settle  to  the  bottom.  The  washing  by  steps  is  an  extension  of  the  preceding 
plan.  To  form  an  idea  of  this,  let  us  imagine  a  series  of  grates  placed  successively  at  dif- 
ferent levels,  so  that  the  water,  arriving  on  the  highest,  where  the  ore  for  washing  lies, 
carries  off  a  portion  of  it,  through  this  first  grate  upon  a  second  closer  in  its  bars,  thence  to 
a  third,  &c.,  and  finally  into  laljyrinths  or  cisterns  of  deposition. 

The  grillea  anglaises  are  similar  to  the  sleeping  tables  used  at  Idria.  The  system  of 
these  gradins  is  represented  in  Jig.  4G9.     There  are  5  such  systems  in  the  works  at  Idria 

469 


tol3L^ 


1 


for  sorting  the  small  fragments  of  quicksilver  ore  intended  for  the  stamping  mill.  These 
fragments  are  but  moderately  rich  in  metal,  and  are  picked  up  at  random,  of  various  sizes, 
from  that  of  the  fist  to  a  grain  of  dust. 

The  ores  are  placed  in  the  chest  a,  below  the  level  of  which  7  grates  are  distributed,  so 
that  the  fragments  which  pass  through  the  first,  6,  proceed  by  an  inclined  conduit  on  to  the 
second  grate,  o,  and  so  in  succession.  (See  the  conduits  I,  o,  p.)  In  front,  and  on  a  level 
with  each  of  the  grates  b,  c,  d,  &c.,  a  child  is  stationed  on  one  of  the  floors,  1,  2,  3,  to  7. 

A  current  of  water,  which  falls  into  the  chest  a,  carries  the  fragments  of  ore  upon  the 
grates.  The  pieces  which  remain  upon  the  two  grates  b  and  c,  are  thrown  on  the  adjoining 
table  V,  where  they  undergo  a  sorting  by  hand ;  there  the  j)ieces  are  classified,  1,  into 
gangue  to  be  tlirown  away  ;  2,  into  ore  for  stamping-mill ;  3,  into  ore  to  be  sent  directly  to 
the  furnace.  The  pieces  which  remain  on  each  of  the  succeeding  grates,  d,  e,f,  g^  h,  are 
deposited  on  those  of  the  floors,  3  to  7,  in  front  of  each.  Before  every  one  of  these  shelves 
a  deposit-sieve  is  established,  (see  <,  «,)  and  the  workmen  in  charge  of  it  stand  in  one  of 
the  corresponding  boxes,  marked  8  to  12.  The  sieve  is  represented  only  in  front  of  the 
chest  //,  for  the  sake  of  clearness. 


470 


"v^fe^^jr^^Sft^^s^S^^^^^^^^s^^^^J^^^i^^^^a 


ORES,  DRESSING  OF. 


843 


Each  of  the  workmen  placed  in  8,  9,  10,  11,  12,  operates  on  the  heap  before  him  ;  the 
upper  layer  of  the  deposit  formed  in  his  sieve  is  sent  to  the  stamping-house,  and  the  infe- 
rior layer  directly  to  the  furnace. 

As  to  the  grains  which,  after  traversing  the  five  grates,  have  arrived  at  the  chest  ar,  they 
are  washed  in  the  two  chests  y,  which  are  analogous  to  the  German  chests.  The  upper 
layer  of  what  is  deposited  in  y  is  sent  to  the  furnace  ;  the  rest  is  treated  anew. 

The  kiln  before  adverted  to  is  explained  by  Jig.  470. 

The  vein  stuff  is  brought  from  the  shaft  by  means  of  tram  wagons,  into  the  hopper  a  ; 
water  flows  from  the  launder  b,  one  portion  distributing  itself  at  the  foot  of  the  hopper,  the 
other  upon  a  cast-iron  plate  perforated  with  holes  l;j  inch  diameter  at  top,  li  inch  diameter 
at  bottom,  and  2  inches  distant  from  centre  to  centre  ;  the  plate  being  4  feet  by  3  feet  6 
inches.  Between  c  and  e,  the  washer  stands.  The  fine  stuff  he  rakes  through  the  plate-holes, 
and  that  which  is  too  coarse  is  drawn  to  e.  Children  standing  on  n,  select  the  prill  and 
dradge  from  the  pile  e,  discharging  such  stones  as  are  valueless  through  the  shoot  f,  into 
the  wagon  beneath.  The  trommel  d  is  constructed  of  perforated  plates,  having  different 
degrees  of  fineness,  in  order  to  size  the  stuff  which  passes  through  into  bins  or  compart- 
ments. 

Ragging. — It  has  been  remarked  that,  in  breaking  the  lode  underground,  numerous 
rocks  are  produced  throughout  which  valuable  ore  is  more  or  less  disseminated.  After  these 
stones  are  washed  they  are  ragged.  This  operation  consists  simply  in  reducing  the  stones 
to  a  smaller  size,  and  rejecting  as  many  of  the  sterile  stones  as  can  be  readily  picked  out. 
The  reserved  heap  is  ultimately  taken  to  the  spallers  and  cobbers.  The  weight  of  a  steel- 
headed  ragging  hammer  varies  from  six  to  eight  pounds. 

SpalUng,  Jig.  472,  is  usually  performed  by  women.     The  object  is  to  break  the  stones 


471 


to  a  proper  size  for  the  bucking-hammer  or  crushing-mill,  and  at  the  same  time  to  cast  aside 
such  lumps  as  are  destitute  of  ore.  The  hammer  employed  is  made  of  cast  steel,  and  is  set 
upon  a  light  pliant  handle.  Its  weigkt  is  about  sixteen  ounces,  and  its  cost  eightpence.  A 
practised  spaller  will  produce  about  one  ton  of  stuff  per  day,  but  the  quantity  must  neces- 
sarily depend  upon  the  hardness  and  nature  of  the  stone. 

Cobbing,  Jig.  473. — This  work  is  also  generally  performed  by 
women  or  young  girls.  It  consists  of  picking  the  best  work  from 
the  dradge,  and  with  a  peculiarly  shaped  hammer  detaching  from 
each  piece  the  inferior  portions,  and  thus  forming  either  prill  or 
l>est  dradge  ore.  An  expert  cobber  will  manage  to  pass  through 
her  hands  about  ten  hundred  weights  of  tolerably  hard  stuff  per 
ten  hours. 

Si.ziiig  Apparatus. — In  the  varied  processes  of  dressing,  no 
point  is  of  greater  importance  than  that  of  correctly  sizing  the 
v^'in  stuff,  neither  is  there  one  demanding  the  exercise  of  a  more 
c  irrect  judgment.  If  the  particles  of  ore  be  reduced  below  their 
natural  size,  a  source  of  loss  is  immediately  created,  whilst,  if  they 
are  not  brought  within  the  limit  of  their  size,  a  portion  of  waste  will  probably  adhere  to 
cacli  atom,  forming  a  serious  difference  in  the  aggregate  quantity  of  castaways,  althougli 
sucli  waste  may  afford  ))ut  a  low  average  percentage.  The  holes  in  the  sieves  or  tronmiels 
sliould  therefore  be  proportioned  to  the  nature  of  the  ore,  but  such  apparatus  should  also  be 
introduced  wherever  necessary.  To  the  crushing-mill,  trommels  art;  essential,  whilst  it  will 
be  found  highly  advantageous  to  cniploy  them  for  the  purpose  of  dividing  (he  stnlf  wher- 
ever it  may  become  intermixed  Tl)e  simplest  form  of  sizing  is  jjerliaps  hy  the  hand  rid- 
dle, Jig.  474,  which  is  formed  of  a  circular  hoop  of  oak,  2  of  an  inch  thick  and  six  inches 
d-ep.      Its  diameter  ranges  from  eigliteon  to  twenty  inches. 


8U 


ORES,  DRESSING  OF. 


The  bottom  is  made  of  a  meshwork  pf  copper  or  iron  wire.     The  weight  of  an  iron  wire 
riddle  is  about  seven  pounds,  and  its  cost  4s.  6d. 


I 


^;<^/^^:4*«-^f^;;;'r 


F?g.  475  represents  a  swing  sieve  employed  in  the  mines  on  the  Continent,  a,  box  into 
which  the  stuft'  to  be  sifted  is  introduced  ;  6,  regulating  door  ;  c,  pendulating  rod  attaching 
the  sieve  frame  to  the  frame  e  ;  /,  friction  roller  carrying  the  sieve  frame  ff.  At  A  springs 
are  fitted  to  each  side  of  the  frame,  in  order  to  give  it  a  vibratory  action,  i,  rod,  giving  mo- 
tion to  the  apparatus.  The  width  of  the  sieve  frame  is  about  one-third  its  length,  but  the 
sieve  bottom  only  extends  from  the  box  a  two-thirds  of  the  length.  The  bottom  of  the 
sieve  frame  is  subsequently  contracted  so  as  to  form  a  shoot.  At  the  extensive  mines  of 
Comorn,  near  Duren,  these  sizing  frames  are  largely  employed  in  connection  with  stamping- 
mills. 

The  circular  hand-riddle  has  only  recently  been  introduced  into  the  mines  of  Cornwall. 
Although  this  is  in  advance  of  hand  riddling,  yet  it  is  by  no  means  equal  to  the  large  sizing 
trommels  employed  in  Germany. 

The  ore  is  thrown  in  at  a,  Jig.  476,  the  coarser  pieces  passing  longitudinally  through  the 

476 


riddle  into  the  shoot  b.  The  riddle  is  turned  by  a  hook  handle,  as  shown  in  the  illustra- 
tion ;  tlie  meshes  of  the  sieve  vary  from  f  of  an  inch  to  one  inch  square,  according  to  the 
character  and  quality  of  the  vein  stuff  to  be  operated  upon. 

Fiffs.  477,  478  show  an  elevation  and  ground  plan  of  a  series  of  flat  separating  sieves. 
A  a',  B  b'  is  a  strong  wooden  frame  ;  m  m,  guides  for  frame  ;  n  n  n,  basement  upon  which 
the  sieve  frame  rests  ;  p,  cistern  fitted  with  perforated  plate  through  which  clean  water  is 
distributed  upon  the  sieves ;  t,  hopper  supplying  the  stuff  to  be  sifted  ;  s  s  bottom  of  ditto. 
The  sieves  are  lifted  by  the  rod  /,  and  make  from  40  to  50  beats  per  minute.  The  sieves 
are  set  about  eight  inches  apart,  and  discharge  the  stuff'  upon  the  inclines  p  p  p. 

The  holes  in  No.  1  sieve  are  ^  inch  diameter. 
"2  t  " 

3  7.6 

The  apparatus  is  employed  in  the  Clausthal  Valley. 

Fig.  479  represents  the  trommel  or  sizing  sieves  in  operation  at  the  Devon  Great  Con- 
sols. Although  the  yield  of  ore  at  these  mines  is  extremely  large,  it  may  not  be  generally 
known  that  nmch  of  it  is  obtained  from  stuff  yielding  no  more  than  from  f  to  H  i)er  cent, 
of  metal.  The  product  of  the  lode  on  arriving  at  the  surface  is  cobbed  and  divided  into 
two  classes,  the  first  going  to  market  without  further  elaboration,  whilst  the  dradge  or  infe- 
rior portion  is  treated  l)y  various  processes  of  washing.  The  whole  is  however  crushed  to 
such  a  degree  of  fineness  as  to  pass  through  the  followiug_  holes : — 


ORES,  DRESSING  OF. 
Trommel  a,  boles  '/ao  inch  diameter. 

")  hi 

"  C,      "      Vio 


845 


■  .^^^\«^' 


rli.  Jil!.*T,™'''  "n  ^''''''  t^^""^  '""-  "^  '"^^*^^  d''^™^^*^'-  »t  tf'^^  '"'•Kc  end,  and  18  inches 
%1%1  s'uterS  ""'.'"^  ''  "^^'"^*°"^  P^^  ™'""^^'  '^"^  ^'^^s'ther  affording  ante" 


846 


ORES,  DRESSING  OF. 
Crushing  JIachixery. 


Various  crushing  machines  are  described  under  Grinding  and  Crushing  Machinery  ; 
but  it  may  be  observed  that  this  section  of  the  dressing  department  deserves  careful  attention, 
as  the  results  are  more  or  less  ati'ected  according  to  the  mode  of  working  and  adjusting  this 
class  of  machinery.  The  crusher  is,  as  it  were,  the  starting  or  radiating  point  for  treating 
the  dradge  work,  and  if  considerable  care  is  not  exercised  hero,  not  only  will  there  be  much 
loss  of  power,  but  also  of  the  initial  quantity  of  ore.  In  the  mining  districts  of  this  coun- 
try it  is  usual  to  introduce  rough  and  fine  dradge  together ;  no  preliminary  division  of  the 
stuff  is  attempted  ;  the  hopper  is  continuously  charged,  and  that  portion  which  is  not  re- 
duced sufficiently  fine  is  returned  by  the  raft'-wliecl  to  be  recrushed. 

The  consequence  is,  the  motion  is  uneven,  strains  arc  inflicted  on  the  machinery,  and 
more  time  as  well  as  power  is  necessary  for  the  purpose  of  realizing  a  given  result.  Valu- 
able improvements  could  be  effected  by  first  mechanically  sorting  or  dividing  the  dradge, 
expediting  the  speed  of  the  rolls,  fitting  them  with  steel  faces,  setting  them  so  as  not^o 
reduce  the  grain  of  ore  below  its  normal  size,  giving  them  a  uniform  supply  by  means  of  a 
tilting  shoot,  and  instead  of  returning  the  raff  to  tlie  rolls  conveying  it  to  a  second  series 
of  smaller  dimensions,  adjusted  and  managed  in  a  similar  way.  To  each  set  of  rolls  there 
should  be  fitteu  sifting  trommels,  with  holes  pioportioned  to  the  character  of  the  ore,  whilst 
in  many  instances  it  would  be  found  judicious  to  discharge  a  stream  of  water  on  the  rolls 
with  a  view  of  expediting  the  crushing. 

In  small  mines,  buckbuj,  jig.  480,  is  resorted  to  instead  of  employing  the  crushing-mill. 

480 


481 


This  operation  consists  of  pounding  pieces  of  mixed  ore  on  a  slab  of  iron  a,  by  means  of  a 
hammer  og  bucker  b.  The  wall  on  which  the  plate  a  is  placed,  is  about  3  feet  high.  The 
stuff  to  be  pounded  is  placed  behind  tlie  slab,  and  is  drawn  upon  and  swept  off  the  plate  by 
the  left  hand.  In  Cornwall  it  is  customary  to  keep  time  with  the  blows  and  to  stand  to  the 
bench,  but  in  Derbysliire  each  operator  works  independently,  and  is  usually  seated.  * 

The  bucker,  fig.  481,  is  formed  of  a  wrought-iron  steel-faced  plate  a,  3  inches  square, 
with  a  socket  b,  for  receiving  a  wooden  handle  c.     Its  cost  i§  about  Is.  4J. 

Stamps. 

Tin  and  some  other  of  the  more  valuable  ores  are  usually  associated  with  and  minutely 
disseminated  in  a  hard  crystalline  gangue,  requiring  to  be  reduced  to  a  fine  powder  before 
the  valuable  portions  can  be  extracted. 

Various  contrivances  have  been  employed  for  this  purpose,  but  none  of  them  seem  to 
have  entered  into  competition  with  the  stamping-mill.  This  apparatus  essentially  consists 
of  a  number  of  cast  iron  pestles,  each  measuring  about  20  inches  high,  and  6  by  10  mches 
in  the  section.  These  are  secured  either  to  a  wroug!it-iron  or  wooden  lifter  ;  a  projecting 
arm  is  placed  towards  the  top  on  each  lifter,  whiih  may  be  slidden  up  and  down  so  as  to 
meet  the  wear  of  the  pestle  or  any  other  irregularity.  These  lifters  are  retained  in  their 
vertical  position  by  suitable  metal  or  wooden  supports.  Motion  is  communicated  by  a 
revolving  shaft  in  front,  fitted  with  four  or  five  projecting  cams,  each  of  which  catcl.es  the 
arm,  and  lifting  the  pestle  from  8  to  10  inches,  lets  it  suddenly  fnll  on  the  substances  which 
may  be  underneath.  The  bottom  on  which  the  heads  fall  is  formed  by  introducing  hard 
stones  or  other  suitable  material,  and  pounding  it  until  it  becomes  sufficiently  solid.  In 
most  parts  of  the  Continent  of  Europe,  on  the  contrary,  stami)ing-mills  are  provided  with 
solid  cast-iron  bottoms  ;  these  are,  however,  subject  to  the  inconvenience  of  requiring  fre- 
quent renewal. 

Around  the  pestles  a  wooden  box  or  cofer  is  constructed,  and  covered  in  at  tlie  top ;  the 
back  is  partly  open  at  the  bottom  in  order  to  admit  the  vein  stuff.  On  each  side  one,  and 
in  front  two  openings  are  made,  7  or  8  inches  square,  which  ^re  fitted  with  wrought-iron 


ORES,  DRESSING  OF. 


847 


lV.i:ne.s,  for  the  reception  of  perforated  iron,  copper,  or  brass  plates,  the  bur  of  the  punch 
or  drill  being  towards  the  inside.  As  a  precaution  against  the  speedy  destruction  of  the 
cofer  from  the  constant  scattering  of  fragments  of  stone,  the  inside  is  partially  lined  with 
sheet-iron.  The  stuft"  to  be  stamped  is  supplied  on  an  inclined  plane,  connected  with  a  hop- 
per at  the  back,  in  the  front  of  which  is  a  launder  for  affording  a  stream  of  water  to  the 
cofer.  The  stamped  stuff  passes  through  the  grates  into  launders,  and  is  thus  directed  to 
the  floors.  When  water  is  the  motive  power,  the  number  of  heads  is  limited  by  the  volume 
and  fall  of  water  available  ;  three  heads  are  the  least  number  used,  but  a  larger  number  is 
generally  preferred.  When  steam-power  is  employed,  a  battery  of  heads  sometimes  includes 
100  or  more  pestles.  When  in  action,  these  are  elevated  from  40  to  80  times  per  minute, 
according  to  the  character  of  the  stuff  to  be  reduced.  The  pulverization  is  said  to  be 
greatly  facilitated  by  having  four  heads  in  the  same  chest  or  cofer,  about  24^  inches  apart. 
Each  head  is  lifted  separately,  and  the  cams  by  which  this  is  done  are  so  disposed  on  the 
axle  as  to  make  the  blows  in  regular  succession.  Great  care  is  also  taken  whether  it  be  in 
a  large  or  small  battery,  to  prevent  any  two  pestles  falling  at  the  same  instant ;  the  object 
being  to  secure  an  equal  strain  against  the  power.  Practical  dressers  are  not  well  decided 
as  to  the  order  in  which  the  lifting  of  four  heads  in  one  cofer  should  take  place,  whether 
one  of  the  inner  pestles  should  precede  the  other,  or  whether  a  side  pestle  should  be  first 
lifted.  A  preference,  however,  seems  to  be  given  to  the  following  method : — supposing  a 
spectator  to  stand  in  front  of  a  4-head  stamps,  left  side  pestle  first,  right  side  second,  right 
middle  third,  left  middle  last. 

Fig.  482  represents  the  elevation  of  a  steam  stamps  employed  in  Cornwall,     a,  axle  ; 

482 


n,  cams  for  lifting  heads  ;  c,  tongue  or  projection  on  lifter;  D  D,  guides  for  retaining  lifter; 
E,  the  lifter  ;  f,  he;id  or  pestle  ;  g,  chest  or  cofer  ;  ii,  hopper  ;  j,  pass  connecting  cofer  and 
hopper  ;  k,  launder  discharging  water  into  the  cofer  ;  l,  stamps  grate  ;  m,  launder  receiving 
the  stuff  which  has  been  flushed  through  the  grates ;  n,  the  bottom  or  bed  of  stamps. 

The  stamping  process  is  not  so  simple  as  it  may  appear  at  first  sight.  Many  of  its  par- 
ticulars, such  as  the  form  of  the  cofer,  mode  of  exit  for  the  stuff,  weight  and  rapidity  of  the 
pestles,  and  quantity  of  water  employed,  must  be  varied  to  suit  the  mode  of  dissemination 
and  the  structure  and  character  of  the  ore,  as  well  as  of  the  matrix.  Fineness  of  retiuction 
is  l)y  no  means  always  a  desideratum,  for  if  some  kinds  of  stuff"  be  reduced  too  low,  much 
of  the  ore  contained  in  it  will  be  w.isted,  hence  considerable  judgment  is  necessary  in  select- 
ing the  grate  best  adapted  to  the  stuff  to  be  operated  upon.  Sometimes  the  grate  is  re- 
placed by  the  "  flosh,"  which  consists  of  a  small  hopper-shaped  box,  fitted  to  the  front  of 
the  grate-hole.  This  box  is  provided  with  a  shutter,  which  is  raised  or  lowered  according 
as  the  ore  is  required  in  a  fine  or  rough  state.  In  dry  stamping  the  fineness  of  the  powder 
depends  not  on  the  grate,  but  on  the  weight  of  the  pestles,  the  height  of  their  fall,  and  the 
period  of  their  action  upon  the  substances  beneath  them.  The  following  practical  results 
are  derived  from  the  steam  stamps  at  rol))erro  Tin  Mines,  Cornwall : — 

Cylinder  of  engine,  86  inches  diameter. 

Diameter  of  the  fly-wheels,  150  feet. 

Weight  of  ditto,  with  cranks,  shaft,  and  bolts,  A1\  tons. 

Power  employed,  55  horses. 

Reduced  in  12  months,  30,201  tons  of  vein  stuff. 


848 


OPwES,  DRESSING  OF. 


Average  number  of  revolutions  of  stamps  axles  per  minute,  8^. 

Number  of  heads  lifted  per  minute,  12,  each  9  inches  high. 

Weight  of  each  head,  600  lbs. 

Average  number  of  blows  performed  by  each  head,  45. 

Weight  of  heads  collectively,  19^  tons. 

Number  of  grates,  72. 

Exposed  area  of  front  grates,  9  x  6  =  54  inches. 
Ditto        of  end  grates,  8  x  6  =  48  inches. 

Number  of  "holes  to  the  square  inch,  140. 

Co,«t  of  stamping,  including  maintenance  of  engine  and  wear  and  tear  of  machinery,  Is. 
Zid.  per  ton  of  stuff. 

Jigging  Machinery. 

In  the  jigging  sieve  only  the  initial  velocity  of  the  substances  to  be  separated  is  ob- 
tained at  each  stroke.  Were,  however,  the  sieve  plunged  to  a  depth  of  say  20  or  30  feet, 
the  various  grains  would  settle  themselves  according  to  their  various  velocities  of  fall,  one 
over  the  other,  assuming  them  to  be  of  a  uniform  size. 

The  following  table,  furnished  by  Mr.  Upfield  Green,  shows  the  fall  of  various  spheres 
in  water  in  one  second,  the  depth  being  in  Prussian  inches  : — 


Diameter 
Lines. 

Gold. 
Spec.  Gr.iv.  19-2 
Prussian  Inches. 

Galena, 
Spec.  Gr.iv.  T-5 
Prus.sian  inches. 

Blemle. 

Spec.  Grav.  4 

Prussian  inches. 

Quartz. 
Spec.  Grav.  26 
Prussian  inches. 

8-         • 

100- 

60-093 

40-825 

29-814 

5-657 

84-090 

50-532 

34-329 

25-071 

4- 

70-711 

42-492 

28-868 

21-082 

2-828 

59-460 

35-731 

24-275 

17-728 

2- 

50- 

30-046 

20-412 

14-907 

1-414 

42-045 

25-266 

17-165 

12-535 

1- 

35-355 

21-246 

14-434 

10-541 

0-70. 

29-730 

17-866 

12-137 

8-864 

0-5 

25- 

15-023 

10-206 

7-454 

0-354 

21-022 

12-633 

8-582 

6-268 

0-25 

17-678 

10-623 

7-217 

5-270 

Now,  instead  of  assuming  the  substances  to  be  of  a  uniform  size,  let  it  be  supposed  that 
they  vary ;  the  foregoing  table  will  show  that  gold  of  8  lines  would  settle  at  bottom,  and 
that  when  gold  of  2-9  lines  began  to  settle,  the  galena  of  8  lines  would  fall  also.  With 
galena  of  3|  lines,  blende  of  8  lines  would  be  associated,  and  so  on. 

If,  secondly,  it  be  assumed  that  the  substances  varied  between  4  and  8  lines,  some  time 
would  elapse,  after  gold  of  4  lines  had  settled,  before  the  galena  would  begin  to  deposit 
itself.  With  blende;  however,  of  4  lines,  and  quartz  of  8,  the  latter  would  almost  appear 
at  the  bottom  at  the  same  time. 

The  proportion  between  the  maximum  and  minimum  sizes  of  the  stuff  to  be  operated  on 
should  be  as  the  specific  gravity  of  one  to  the  other.     Thus, 

Gold  and  galena 7-5  :   19-2  :  :   1  =  2-56 

Galena  and  blende 4-0:     7-5  ::  1  =  1-075 

Blende  and  quartz 2-6  :     4-0  :  :   1  =  1-537 

Hand  Sieve. — This  apparatus,  fie/.  483,  is  formed  of  a  circular  hoop  of  oak,  f  of  an 
inch  thick  and  6  inches  deep.  Its  diameter  ranges  from  18  to  20  inches.  The  bottom  is 
made  of  copper  or  iron  wire  meshes,  of  various  sizes.  Sometimes  perforated  copper  plate 
is  employed,  when  the  sieve  is  termed  a  copper  bottom.  The  sieve  is  shaken  with  the  two 
hands  in  a  cistern  or  tub  of  water ;  an  ore  vat  is  however  sometimes  employed,  and  either 
fixed  horizontally  or  in  an  inclined  position.  In  using  this  sieve  the  workman  shakes  it  in 
the  vat  with  much  rapidity  and  a  dexterous  toss  till  he  has  separated  the  totally  sterile  por- 
tions from  the  mingled  as  well  as  from  the  pure  ore.  He  then  removes  these  several  quan- 
tities with  a  sheet-iron  scraper,  called  a  limp,  and  finds  beneath  them  a  certain  portion  of 
enriched  ore. 

483  484 


J^^ 


Deluinr/  Sicve.-^This  sieve,  a,  fff.  484,  is  either  constructed  with  a  hair  or  canvas  bot- 


ORES,  DRESSING  OF. 


849 


torn  ;  the  former  is  more  expensive,  but  more  durable.  Its  peculiar  application  is  chiefly 
for  the  final  treatment  of  ores  previous  to  being  put  to  pile,  such  ores  having  first  passed 
through  the  finest  jigging  sieves,  yet  still  maintaining  a  certain  degree  of  coarseness,  and 
bearing  a  high  specific  gravity. 

In  the  separation  of  ores  from  .light  waste,  or  such  minerals  as  approach  one  another 
somewhat  closely  iu  their  densities,  this  form  of  sieve  is  both  good  and  effective,  but  to  use 
it  properly  a  considerable  amount  of  dexterity  and  practice  is  requisite. 

There  are  two  principal  methods  of  using  it ;  by  one  a  motion  is  given,  whereby  the 
waste  is  being  constantly  projected  and  carried  over  the  rim  into  the  kieve  by  a  current  of 
water  forced  through  its  bottom.  This  mode  of  treatment  is  adapted  for  poor  ores.  In  the 
second  case,  when  the  ore  is  nearly  pure 
but  still  associated  with  a  heavy  gangue,  a 
motion  is  given  to  the  sieve  whereby  the 
water  is  forced  through  the  ore,  and  made 
to  traverse  the  surface  of  the  mineral  in 
concentric  circles.  This  motion  collects 
the  waste  into  the  middle  of  the  clean  re- 
sult. By  the  first  method  about  six  tons 
per  day  may  be  passed  through  by  each 
workman  and  enriched  for  the  second 
operation.  The  weight  of  the  sieve  varies 
from  four  to  five  pounds,  its  diameter  is 
twenty  iix  inches,  depth  four  inches,  and 
cost  from  2s.  3d.  to  2s.  6c?. 

A  jigging  sieve,  constructed  as  shown 
in  Jig.  485,  is  sometimes  employed  on  the 
Continent,  x  represents  the  table  on 
which  the  mineral  is  placed  ;  b  is  a  large 
kieve  of  water,  in  which  the  sieve  is  sus- 
pended by  the  iron  rod  d,  set  in  motion 
by  means  of  the  arrangement,  f,  g,  h,  sus- 
pended at  I,  and  having  at  the  extremity 
H  a  box  for  the  reception  of  small  stones, 
to  be  used  for  the  purpose  of  counterpois- 
ing the  weight  of  the  sieve  and  several 
fittings.  By  moving  the  rod  f,  sliding  in 
K,  the  workman  gives  the  required  motion 
to  the  sieve,  and  when  its  contents  have 
been  sufficiently  washed  he  removes  them  by  the  same  means  as  when  the  hand  sieve  is  em- 
ployed. 

I{a7id  Jigging  or  Brake  Sieve. — The  brake  sieve,  Jig.  486,  is  rectangular,  as  well  as  the 

486 


cistern  in  which  it  is  agitated,  a,  wooden  lever,  having  its  axis  at  f  ;  n,  piece  of  wrought- 
iron  bolted  to  end  of  lever  a,  whilst  its  upper  end  passes  freely  through  a  slot  opening  in 
lever  n,  and  having  two  shoulder  projections  c  ;  e,  axis  of  lever  d  ;  g,  bars  connected  with 
lever  d,  supported  on  axle  e,  and  from  which  the  iron  rods  h  ii  deiiend  ;  j,  rectangular 
sieve  ;  k,  under  hutch  ;  l,  shoot  for  overflow  of  water  ;  m,  receptacle  for  retaining  any  fine, 
Vor,.  III.— .54 


850 


ORES,  DRESSING  OF. 


ORES,  DRESSING  OF. 


85] 


ore  which  may  escape  with  the  water  from  l,  as  well  as  for  receiving  the  hutchwork.  A 
boy  placed  near  the  end  of  lever  a,  by  the  action  of  leaping,  jerks  it  smartly  up  and  down, 
so  as  to  shake  effectually  the  sieve  j.  Each  jolt  not  only  makes  the  fine  part  pass  through 
the  meshes,  but  changes  the  relative  position  of  those  which  remain  in  the  sieve,  bringing 
the  purer  and  heavier  pieces  eventually  to  the  bottom.  The  mingled  fragments  of  ore  and 
stony  substances  lie  above  them,  while  the  poor  and  light  pieces  are  at  the  top  ;  those  are 
first  scraped  off  by  the  limp,  then  the  mixed  portion,  and  lastly  the  ore,  which  is  usually  car- 
ried to  the  ore  heap.  The  sieve  frame  may  be  made  2x4  feet  inside  and  8  to  9  inches 
deep  The  hutch  should  then  be  5  feet  long,  3^  feet  wide,  and  4|  feet  deep,  constructed  of 
good  deal  boards  2  inches  thick.  The  quantity  of  stuff  which  a  boy  can  jig  in  ten  hours 
will  depend  upon  several  circumstances.  With  a  sieve  six  holes  to  the  square  inch  and  a 
tolerably  light  waste,  from  five  to  six  tons  can  be  operated  on. 

Machine  Jic/rjiug. — The  machine  jigger  represented  in  Jig.  487  is  constructed  on  the 
same  principle  as  the  hand  apparatus.  The  hutches  are,  however,  somewhat  larger,  being 
six  feet  long,  four  feet  wide,  and  four  feet  deep,  a,  fly-wheel ;  b,  driving-wheel ;  c,  cog- 
wheel receiving  motion  from  b,  and  giving  motion  to  a  crank  from  which  depends  a  rod 
attached  to  lever  d.  m  e,  the  vertical  rod,  passes  through  a  slot  opening  in  the  wooden 
lever  f,  and  by  these  several  combinations  a  vertical  movement  and  jerk  is  given  to  the 
sieve  contained  in  the  cistern  g. 

When  it  is  required  to  discharge  the  sieve,  the  lever  h  is  depressed,  and  the  pin,  not 
seen  in  the  end  of  lever  f,  traverses  in  the  slot  shown  in  the  bridle  rod  immediately  below 
the  bracket.  The  sieve  measures  4x2  feet  and  9  inches  deep.  It  is  strengthened  by  iron 
bauds  and  numerous  slips  across  the  bottom. 

A  jigging  apparatus,  fig.  488,  has  been  arranged  by  Mr.  Edward  Borlase,  of  St.  Just, 
Cornwall,  and  introduced  by  him  at  Allenheads,.with  satisfactory  results.  At  these  mines 
it  has  been  worked  in  conjunction  with  the  machine,  fig.  496,  and  described  at  page  857. 
The  larger  and  denser  portion  of  stuff  separated  by  this  apparatus  is  conveyed  by  suitable 
launders  to  a  series  of  sieves,  arranged  on  the  top  of  a  conical  reservoir,  furnished  with  a 
feed  pipe  for  the  admission  of  water,  and  with  an  outlet  pipe  at  the  bottom.  This  reservoir 
is  placed  within  another  reservoir,  also  in  the  form  of  an  inverted  cone,  and  provided  with 
an  outlet  pipe  at  the  lower  part,  a,  eccentric  giving  motion  to  the  sieve  ;  b,  launder  con- 
veying stuff  to  such  sieves ;  c,  distributor,  either  stationary  or  revolving,  as  may  be  re- 
quired, delivering  stuff  to  the  sieves  arranged  on  the  top  of  the  conical  reservoir ;  f,  valve 
for  discharging  the  finer  portion  of  the  ore ;  G  G,  internal  cistern  furnished  with  an  outlet 
valve  H. 

The  sieves  have  a  slight  outward  inclination,  and  the  refuse  substances  with  the  waste 
water  are  carried  over  and  deposited  in  the  conical  cistern,  G  g. 

The  sieves  should  make  from  150  to  200  pulsations  per  minute,  according  to  the  quan- 
tity and  character  of  the  stuff  under  treatment. 

The  following  is  the  result  of  trials  made  on  160  tons  of  stuff,  one-half  being  delivered 
to  Borlase's  machine,  the  other  to  the  common  jigging  hutch  : — 


Difference  in 

Machine. 

Hutchers. 

favor  of  Bor- 
lase's Mucliine. 

1       Time  .— 

Hours. 

Hours. 

Hours. 

Occupied  hutching  cuttings 

50f 

68^ 

Vi 

Ditto              smiddum  from  do. 

5 

lOi 

6i 

Sludge  machine,  washing  sludge  and  smid- 

dum    -         - 

2H 

I 

Dressing  the  ore  in  a  trunk      ... 

29i 

61H 

lOi 

1  Aggregate  number  of  hours  occupied  bv 

the  lads  in  doing  the  work,  viz.,  feed- 

ing cuttings  and  hutching  smiddum 

IIU 

195f 

84i 

Aggregate  number  of  hours  occupied  by 

the  lads  in  wasliing  sludge  and  smid- 

dum, including  the  final  cleaning  in  a 

trunk  -...-.. 

102 

123 

21 

Cost  :— 

£       s.       d. 

£       s.       d. 

£       s.       d. 

Of   boys    attending    mftchinc,    wheeling 

away  waste,  and  preparing  ore  for  the 

bing-stead 

1 

1       15       9 

2       8       9i 

0       13     Oi 

852 


ORES,  DRESSING  OF. 


Produce : — 

Borlase's  machine 

Hiitchers 

Difference  in  total 
produce  in  favor 
of  Borlase's  ma- 
chine 

Ditto  ditto    - 

Sieve  and  Smlddum  Ore. 

Sludge  Ore. 

Total  Ore. 

Total  Lead. 

St.    lbs. 

Assay.      Lead. 

St.    lbs. 

Assay. 

Lead 

St.        lbs. 

St.       lbs. 

19  10 
17     6i 

p.  cent. 
60 
60 

lbs. 
165-6 
146-7 

32     5f 
13 

p.  cent. 
70 

64 

lbs. 
317-6 
116-5 

52       If 
30       6i 

21       9i 
71  p.  cent. 

34      71 
18     Hi 

15       10 
84  p.  cent. 

Petlicrick^s  Separator.     Figs.  489  and  490.     a,  the  plunger  or  force-pump ;   b,  recep- 
tacles fitted  with  sieves ;   c,  hutch  filled  with  water ;  d,  discharge  holes  fitted  with  wooden 

489 


4  00 


plugs  ;  E,  movable  plate  to  admit  of  withdrawing  the  ore  ;  f,  hopper  with  shoots  for  sup- 
plying sieves ;  n,  beam  for  giving  motion  to  plunger  piston  a  ;  j,  launder  for  delivering 
water  to  hutch. 


ORES,  DRESSING  OF. 


853 


About  the  year  1831,  Mr.  Petberick  introduced  the  above  machine  at  the  Fowey  Consols 
Mines  in  Cornwall.  It  was  described  in  the  Quarttr/i/  Miuing  lierinr^  January,  1832, 
from  which  the  following  is  extracted : — This  machinery  is  particularly  intended  to  super- 
sede the  operation  oi  jigging  in  separating  ores  from  their  refuse  or  waste.  *  *  *  In  the 
separators,  the  sieves  containing  the  ores  to  be  cleaned  are  placed  in  suitable  apertures  in 
the  fixed  cofer  of  a  vessel  filled  with  water,  connected  with  which  is  a  ()lunger  or  piston 
working  in  a  cylinder.  The  motion  cf  the  plunger  causes  the  water  to  rise  and  fall  alter- 
nately in  the  sieves,  and  effects  tne  required  separation  in  a  more  complete  manner  than  can 
be  performed  by  jigging.  The  variety  in  the  extent  and  tjuickness  of  the  motion  required 
for  the  treatment  of  different  descriptions  of  ores  is  easily  produced  by  a  simple  arrange- 
ment of  the  machinery. 

A  principal  advantage  in  this  separator  is  derived  from  (he  sieves  being  stafionary  (in 
jigging,  the  sieve  itself  is  moved)  during  the  process  ;  thereby  avoiding  the  indiscriminate 
or  premature  passing  of  the  contents  through  the  meshes,  which  necessarily  attends  the 
operation  of  jigging,  whether  by  the  brake  or  hand  sieve.  Greater  uniformity  of  motion  in 
the  action  of  the  water,  in  producing  the  required  separation,  is  also  obtained ;  and  supe- 
rior facility  afforded  to  the  deposit  in  the  water  vessel  (especially  in  dressing  crop  ores)  of 
the  finer  and  richer  particles,  which  in  jigging  are  principally  carried  off  in   the  waste  water. 

The  superiority  of  the  patent  separators  over  the  ordinary  means  of  cleaning  ores  will 
perhaps  be  best  shown  by  reference  to  their  actual  performance.  At  tlie  Fowey  Consols  and 
Lanescot  mines  in  Cornwall,  where  they  are  extensively  used,  seventeen  distinct  experiments 
have  been  made  on  copper  ores  of  various  qualities  from  different  parts  of  the  mines,  to 
ascertain  the  extent  of  the  advantage  of  this  mode  of  separation  over  the  operation  of  jig- 
ging. Seventeen  lots  of  ores,  amotmting  together  to  about  300  tons,  were  accurately  divided, 
one-half  was  jigged,  and  the  other  half  cleaned  by  the  separators.  A  decided  advantage 
was  obtained  by  the  latter,  in  every  experiment ;  the  following  are  the  aggregate  results  : — 


Quantity  of 

Marketable  Ores 

returned. 

Percentage 
of  Metal. 

Quantity  of  Metal. 

Value  of  Ores. 

R.v  jigging      - 

By  the  separators  - 

Tons.    Cwt.    Qrs. 
76         19        0 
74         19       0 

8i 

Tons.  cwts.  qrs.  lbs. 

5  19     2     3 

6  9     0  18 

£           ><.        d.     > 
362        1.5        7 
396         6        7 

1 

Difference  in  the 
Value  of  Ores. 

In  the  Labor  of 
Cleaning. 

Total. 

Being  9.9  8d.  per  ton,  on  74  tons 
19  cwt. 

£          «.        d. 
33        11        0 

£           s.          d. 
2          11          4 

£      8.    d. 
S6      1     4 

It  must  be  obvious  to  those  who  are  practically  acquainted  with  the  subject,  that  the 
poorer  the  .stuff  containing  the  ores,  the  greater  must  be  the  relative  value  of  any  improve- 
ment in  the  process  of  cleaning  it.  This  has  been  satisfactorily  demonstrated  by  the  trials 
which  have  been  made  in  the  mines  before  mentioned,  in  dressing  the  tailings,  which  are 
the  refuse  of  the  inferior  ores,  called  halvans.  It  appears  that  these  tailings  may  be  dressed 
by  the  separators  with  more  than  treble  the  profit  to  the  proprietors,  which  could  be  real- 
ized by  the  ordinary  methods ;  and  there  is  no  doubt  that  there  are  vast  quantities  of  sur- 
face ores,  both  copper  and  lead,  in  various  mines,  which  might  be  dressed  by  the  same  means 
with  consideratjle  advantage. 

Edwards  Sf  Beaclicra  Patent  Mineral  and  Coal-Washing  Machine,  consists  of  two  cis- 
terns, rectangular  in  horizontal  section.  Within  a  few  inches  of  tlie  top  of  these,  jierforated 
plates  or  screens,  e,  fg.  491,  are  fixed,  upon  which  the  material  to  be  washed  is  fed  through 
a  hopper,  which  also  connects  the  two  cisterns.  On  the  inner  sides  of  the  cisterns  are  two 
apertures  closed  by  flexible  discs,  or  diaphragms  of  leather,  c,  which,  when  the  machinos 
are  filled  with  water,  cause  it  to  rise  and  fall  tln-ough  a  certain  space,  by  means  of  a  hori- 
zontal vibratory  motion,  which  they  receive  from  an  eccentric  on  a  shaf^t,  which  is  driven 
either  by  a  steam  engine  attached  directly  to  it,  or  by  a  driving-belt  and  pulley,  a.  See 
Wasiii.ng  Coal. 

The  action  of  the  flexible  diaphragms  is  similar  to  that  of  cylinders  and  pistons,  which 
are  sometimes  substituted  for  them.  Above  the  driving-shaft  is  a  smaller  one,  B,  which  is 
driven  at  a  slower  rate  by  means  of  toothed  wheels,  and  gives  by  cranks  or  eccentrics  a 
horizontal  motion  backwards  and  forwards  to  sets  of  scrapers  k,  above  the  cisterns.  These 
are  so  arranged  as  to  remove  the  upper  stratum  of  the  sul)stanco  being  acted  upon,  and  dis- 
charge it  into  wagons  or  other  convenient  rccei)tacles  ;  these  up])er  strata  are  of  course  the 
lightest,  the  heavier  part  settling  upon  the  perforated  jjlates  below. 


854 


ORES,  DRESSING  OF. 
491 


"When  from  the  action  of  the  machine  a  considerable  quantity  of  material  has  accumu- 
lated upon  these  plates,  the  scrapers  are  thrown  out  of  gear  by  means  of  apparatus  attached, 
H  II,  and  the  stuff  raked  off,  the  operation  being  then  continued  on  fresh  supplies.  Doors, 
G  G,  at  the  bottom  of  the  machines,  admit  of  any  fine  stuff  which  may  pass  through  the  per- 
forated plates  being  removed  from  time  to  time  as  may  be  necessary. 

These  machines  are  in  use  for  cleansing  coal  as  well  as  other  mineral  substances. 

In  such  cases  the  heavier  stuff  which  remains  upon  the  plates  consists  of  shale,  pyrites, 
&c.,  very  injurious  substances  in  the  manufacture  of  coke.  One  machine  of  two  connected 
cisterns,  is  capable  of  washing  about  thirty  tons  per  diem  of  coal,  but  the  quantity  of  min- 
eral work  will  depend  upon  the  amount  of  ore  present  in  proportion  to  the  waste.  The  size 
of  the  perforations  in  the  screens  is  adapted  to  the  quality  of  the  material  acted  upon. 

A  gold-washing  machine  has  been  arranged  by  Mr.  John  Hunt,  late  of  Pont-Pean,  France. 
This  gentleman  states  that  it  requires  but  little  water,  and  is  so  contrived  as  to  circulate  this 
water  for  repeated  use  ;  also  that  the  principle  would  be  found  very  successful  if  employed 
on  a  more  extended  scale  ;  this  Mr.  Hunt  intends  to  carry  into  operation  at  some  lead  mines 
in  Cornwall. 

Separators. 

Of  late  years  apparatus  of  this  class  has  been  steadily  coming  into  operation,  not  only 
in  lead  and  copper  mines,  but  also  in  the  dressing  of  tin  ores.  The  prevailing  principle  is 
that  of  directing  a  pressure  of  water  against  the  density  of  the  descending  material,  making 
the  former  sufficiently  powerful  to  float  off  certain  minerals  with  which  the  ore  may  happen 
to  be  associated.  "When  marked  difference  of  densities  exists,  and  the  ore  can  be  readily 
freed  from  its  gangue,  this  mode  of  separation  v.ill  be  found  effective.  Trommels  may  be 
advantageously  employed  for  sizing  the  stuff"  previous  to  its  entry  into  the  several  sepa- 
rators. 

Slime  Separator. — This  apparatus  is  due  to  Captain  Is.aac  Richards,  of  Devon  Great  Con- 
sols, and  is  employed  for  removing  the  slime  from  the  finely-divided  ores  which  have  passed 
through  a  series  of  sieves  set  in  motion  by  the  crusher.  The  finely-divided  ores  are  for  this 
purpose  conveyed  by  means  of  a  launder  upon  a  small  water-wheel,  thereby  imparting  to  it 
a  slow  rotary  motion.  "Whilst  this  is  turning,  time  is  allowed  for  the  particles  to  settle  in 
accordance  with  their  several  densities  ;  the  result  obtained  is,  that  the  heavier  and  coarser 
grains  are  found  at  the  bottom  of  the  buckets,  whilst  the  lighter  and  finer  matters  held  in 
suspension  are  poured  out  of  the  buckets  and  flow  away  through  a  launder  provided  for  that 
piirpose.  The  stuff"  remaining  in  the  bottom  of  the  buckets  is  washed  out  by  means  of  jets 
of  water  obtained  from  a  pressure-column  ten  feet  in  height,  and  passes  directly  into  the 
funnel  of  a  round  buddle. 

The  wheel  a,  fir/.  492,  is  four  feet  in  diameter,  two  feet  six  inches  in  breadth  ;  has 
twenty-four  buckets,  and  makes  five  revolutions  per  minute  ;  b,  launder  for  supplying  the 
finely-pulverized  ore ;  c,  pressure-column ;  n,  jet-piece  ;  e,  launder  for  conveying  off'  the 
slime  overflow  of  the  wheel ;  f.  launder  for  conveying  roughs  to  round  buddle.  A  modifi- 
cation of  tl'.is  apparatus  is  employed  at  the  Wildberg  mines  in  Germany,  where  it  has  been 
recently  introduced,  and  is  found  to  succeed  admirably  for  the  classification  of  finely-divided 
ores. 


ORES,  DRESSING  OF. 

492 


855 


493 


Sizing  Cistern. — The  tails  from  round  buddies  are  sometimes  passed  through  this  appa- 
ratus. It  consists,  fig.  493,  of  a  wooden  box  provided  with  an  opening  at  the  bottom,  a, 
which  is  in  communication  with  a  pres- 
sure-pipe, B,  an  outlet,  c,  and  has  a  small 
regulating  sluice,  d.  The  stuff  from  the 
buddies  enters  at  E,  and  the  pressure  in 
the  columns  is  so  regulated  as  to  allow  the 
heavier  particles  of  the  stuff  to  descend, 
but  at  the  same  time  to  wash  away  at  f 
the  lighter  matters  that  may  be  associated 
with  the  ore.  This  is  done  by  having 
the  outlet  c  of  less  area  than  the  inlet, 
and  fixing  on  the  extremity  d  a  con- 
venient regulating  sluice,  by  which  means 
a  greater  or  less  quantity  of  stuff  may  be 
passed  over  the  depression  f.  Two  cis- 
terns of  this  kind  are  generally  employed, 
the  second  being  used  to  collect  any 
rough  particles  that  may  have  passed  off 
from  the  first.  The  depth  of  the  first 
of  these  boxes  may  be  eighteen  inches,  its  width  thirteen  inches,  and  its  length  three  feet 
six  inches.     The  dimensions  of  the  second  may  be  considerably  less. 

The  arrrangement  of  another  separating  box  is  shown  in  figs.  494  and  495.  The  slime 
water  flows  in  at  m  ;  and  water  still  holding  a  considerable  portion  of  slime  flows  away  from 
the  opposite  end.  It  is  necessary  that  pieces  of  chip,  small  lumps,  or  other  extraneous  mat- 
ter, should  be  intercepted  previous  to  entering  this  apparatus,  also  that  the  slimes  should 
be  evenly  sized  by  means  of  a  trommel  or  sieve.  The  heaviest  portion  of  the  slime  water 
in  which  the  sand  and  ore  are  contained,  is  discharged  at  o,  which  is  about  an  inch  square. 
The  launders  p  p  are  for  the  purpose  of  conveying  the  slime  water  either  to  buddies  or 
shaking  tables.  The  dimensions  of  the  cistern  No.  1  are,  length,  six  feet ;  width,  one  and 
a  half  feet ;  depth,  twelve  inches.  But  two  other  cisterns  of  .similar  form  are  attached. 
No.  1  cistern  will  work  about  ten  tons  of  stuff  in  twenty-four  hours,  and  by  widening  the 
box  from  eighteen  to  twenty-seven  inches,  it  will  get  through  twenty  tons  in  twenty-four 
hours.  Affixed  to  one  side  of  the  boxes  are  hammers  so  contrived  as  to  give  thirty  blows 
per  minute  in  the  manner  of  a  dolly  tub.  The  sides  of  the  box  have  an  angle  of  fifty  de- 
grees from  the  horizontal.  The  chief  dimensions  of  the  two  cisterns,  viz.,  one  working  ten 
and  the  other  twenty  tons,  are  subjoined. 


No.  of  Box. 

Ten  tons. 

Twenty  tons. 

Lcticth  of 
Box. 

Breadtli  of 
Box. 

Depth  of 
Box. 

Length  of  Breadth  of 
Box.             Box. 

Depth  of 
Bo.x. 

2 
3 
4 

ft. 

9 

12 

15 

ft. 
2 
4 
8 

ft. 

C 

8 

10 

ft.        {         ft, 

9         1         5 

12         1         9 

IG         1       15 

ft. 
6 

8       ! 
10 

856 


OKES,  DRESSING  OF. 
494 


I- ,>h^^ 


^/V < 


According  to  experiments  made  in  the  Stamping-house  of  Schemnitz,  where  twelve  tons 
are  stamped  in  twenty-four  hours,  the  first  cistern  separated  from  the  slimes  40  per  cent,  of 
the  ore  ;  the  2d  cistern,  22  per  cent. ;  the  3d  cistern,  20  per  cent. ;  the  4th  cistern,  12  per 
cent. ;  together,  94  per  cent.,  leaving  a  loss  of  6  per  cent.  From  No.  1  box  every  cubic 
foot  of  water  flowing  through  gave  16  pounds  of  sandy  matter.  No.  2  afforded  13  pounds 
of  finer  stuff.  No.  3,  16  pounds,  and  No.  4  yielded  12  pounds  per  cubic  foot  of  water.  It 
should  be  remarked  that  the  outlet  o  is  proportioned  to  the  dimensions  of  the  machine. 

Borlase^s  Machine,  jig.  496,  has  been  recently  introduced  at  the  Allenheads  Mines,  be- 
longing to  Mr.  Beaumont.  The  ore  and  mineral  substances,  after  passing  through  the 
crushing  apparatus,  are  introduced  at  a,  and  flow  through  the  spaces  b  b,  passing  into  c  c. 
At  the  bottom  is  a  circular  chamber  e  e,  with  a  perforated  cylindrical  plate  f.  Water  under 
pressure  is  supplied  by  the  pipe  g,  and  regulated  by  the  cock  h. 

It  will  be  seen  that  this  apparatus  consists  of  an  external  and  internal  cone  with  a  space 
between  them,  and  that  a  separation  of  the  orcy  matter  is  effected  by  limiting  the  power 
of  the  water  between  the  density  of  the  stuff  to  be  retained,  and  that  which  is  to  be  dis- 
charged at  J  J  into  the  shoot  k. 

At  L  the  larger  and  denser  portion  of  the  mineral  which  has  fallen  through  the  ascend- 
ing current  of  water,  is  conveyed  either  to  a  jigging  machine  or  some  other  enriching  appa- 
ratus. Mr.  Borlase  first  erected  this  apparatus  in  the  United  States  of  America,  where  it 
was  found  to  answer  remarkably  well,  and  he  was  induced  by  this  success  to  attempt  its  gen- 
eral introduction  in  this  country.  In  this  endeavor  he  has  not,  however,  been  as  yet  so 
entirely  successful  as  could  be  wished,  as  the  English  mines,  and  particularly  those  of  Corn- 
wall, are  for  the  most  part  managed  by  individuals  who  require  to  be  fully  convinced  of  the 
utility  of  any  new  invention  before  giving  it  a  trial.  This  machine  has  been  employed  with 
great  success  at  the  mines  of  Allenheads.  The  comparative  results  afforded  by  Borlasc's 
Trunking  Machine  and  the  common  Nicking  Trunks  may  be  seen  from  the  following  statis- 
tical statement. 


ORES,  DRESSING  OF. 

A       ../    496 


857 


Lead  Mines,  Allehneads. 
Results  of  trials  with  Borlase's  4^  feet  Circular  Lead  Ore,  Sludge,  and  Slime  Dressing 
Machine,  and  the  common  Nicking  Trunks,  March,  1859.     Fortj'-four  wheelbarrows  full  of 
exactly  the  same  description  of  slimes  were  put  through  each  of  the  respective  processes. 


Machine  in  operation     - 
Occupied  in  oiling  machinery 
Ditto  emptying      ... 
Stirring,  nicking,  and  empty- 
ing trunks  -         -         .         . 
Occupied  dollying  the  work  - 

Labor  of  men  and  boys  em- 
ployed      .... 

TIME. 

Borlase 

"s  Machine. 

Trunlis. 

Difference.      ! 

Hours. 

15 

0 

2 

0 
1 

Minutes. 
16 
40 
37 

0 
19 

Hours.       Minutes. 
0               0 
0               0 
0               0 

14               3 
2                0 

Hours. 
0 
0 
0 

0 

0 

Min.  ! 
0     i 

0     j 

0 
0, 

19 

52 

16                3 

3 

49 

COST. 

£ 
0 

s.          d. 
4         3* 

£        s.         d. 

0         8         8 

£ 
0 

8.     d. 
4      5 

PROnUCE. 

Ore. 

Lead. 

Ore. 

Lead. 

Ore. 

Lead. 

St.     lbs. 

Ass-iy. 

lbs. 

St.     lbs. 

Ass.iy. 

lbs. 

St.    lbs. 

St.    Ibs.j 

Best  work     -        .        •        - 
Seconds         .... 

Thirds 

Fourths         .... 

54  in§ 

10      3i 

21  9^ 

22  9 

p.  cent. 

65 

46 

30 

8 

498-3 
65-9 
91-0 
25-4 

53      9i 
11    12 

34     2-1 
0     0 

p.  cent. 

64 

46 

12 

0 

180-8 
76-4 
51-4 

0 

109   4t 

680-6 

99      9f 

(•)14-0 

9      8| 

4     1(1 

*  The  cost  is  unduly  heavy,  the  same  value  of  labor  would  have  maintained  three  m.ichines. 


858 


ORES,  DEESSING  OF. 


Fig.  49Y  represents  a  wooden  cistern  a,  having  an  aperture  b  at  the  bottom,  about  an 

inch  diameter,  which  is  alternately  closed 
and  opened  by  means  of  an  iron  plate  c, 
fitted  upon  the  vertical  shaft,  to  which  is 
also  fixed  an  iron  paddle  d,  which  revolving 
horizontally  keeps  the  ore  and  water  in  con- 
stant agitation.  The  tails  from  the  various 
buddies,  as  well  as  the  stuff  from  the  cofers 
at  the  end  of  the  strips,  flow  in  at  e,  and 
pass  through  a  perforated  sizing  plate  f, 
into  the  cistern.  The  rougher  and  heavier 
portions  escape  through  the  hole  B  into  a 
strip  where  it  is  continually  stirred,  in  order 
that  it  may  be  evenly  deposited,  and  at  the 
same  time  freed  from  the  lighter  particles. 
The  overflow  containing  fine  ores  passes  by 
the  launder  g  into  catch  pits,  from  which 
heads  and  middles  are  taken  to  be  elabor- 
ated by  means  of  buddies  or  other  appara- 
tus. \Vhen  this  separator  is  employed  in 
tin  dressing,  it  is  usual  to  divide  the  stuff 
in  the  strip  connected  with  the  bottom  of 
the  box,  into  heads  and  tails.  The  first  is 
taken  direct  to  the  stamps,  and  again  pul- 
verized with  rough  tin  stuff;  but  before 
the  tails  can  be  so  treated,  they  are  re- 
stripped  in  order  to  get  rid  of  extraneous 
matter. 

Wilkin^  Separator. — This  apparatus  is  the  invention  of  Mr.  J.  B.  Wilkin  of  "Wheal 
Basset  and  Grylls,  near  Helston.  He  describes  it  as  a  "  self-acting  tossing-niachine,  by  which 
the  rough  particles  are  separated  from  the  fine  and  prepared  for  the  inclined  plane.  The 
orey  matter  is  carried  into  a  small  cistern  by  a  stream  of  water  which  enters  at  the  top  and 
passes  out  at  the  opposite  side  bearing  the  finer  particles  with  it,  whilst  the  rougher  and 
heavier  particles  escape  at  the  bottom  through  a  rising  jet  of  clean  water,  which  prevents 


the  fine  and  light  particles  from  passing  in  the  same  direction."  a,  fig.  499,  inlet  of  clean 
water;  n,  launder  delivering  the  orey  matter;  c,  outlet  of  fine  and  inferior  stuff;  d,  dis- 
charge orifice  for  rough  and  heavy  stuff.  This  operation  must  be  regulated  by  a  flood-shut. 
A  cistern  10  feet  square  on  the  top,  and  18  inches  deep,  will  pass  through  about  40  tons  in 
10  hours.  When  separating  stamps  work  a  smaller  cistern  is  employed,  say  14  inches 
square,  10  inches  deep ;  this  will  despatch  6  tons  in  10  hours. 

A  valuable  form  of  separator  is  shown  in  fig.  500,  the  peculiarity  of  which  consists  in 
the  manner  of  introducing  the  water  and  slimes.  Instead  of  the  latter  depending  for  sepa- 
ration upon  the  power  of  an  ascending  column  of  water,  it  here  passes  into  a  horizontal 
flow  of  greater  or  less  volume  and  velocity,  produced  by  altering  the  tap  g.  Compart- 
ments, viz.,  1,  2,  3,  and  4,  are  also  fitted  in  the  box,  for  the  purpose  of  receiving  mineral 
of  different  densities  and  size,  which  is  discharged  and  washed  in  strips  set  underneath  ;  a, 
inlet  launder  to  trommel ;  B,  waist  of  sheet-iron  ;  c,  trommel  either  of  perforated  plate,  or 
wire  gauze  ;  d,  shoot  from  trommel  serving  to  convey  away  the  rougher  portions  ;  e,  hop- 
per for  conveying  stuff  to  shoot  h,  and  from  thence  into  the  box  ;  f,  ascending  column  of 
water ;   g,  tap  for  regulating  the  flow  of  water ;  k,  l,  m,  n,  outlet  pipes  for  delivering  the 


OKES,  DRESSING  OF. 


859 


separated  stuff  to  strips  or  buddies  ;  o,  launder  for  receiving  overflow  from  cistern  ;  p,  Q,  r, 
valves  regulating  the  width  of  the  compartments,  also  for  the  purpose  of  effecting  the  dis- 
position of  the  different  minerals  with  which  the  ore  may  be  associated. 


500 


In  addition  to  the  machines  already  described,  a  slime  or  sludge-dressing  apparatus  has 
been  designed  by  Mr.  Borlase,  and  which  he  intends  to  introduce  into  the  mining  districts 
of  this  country.     Fig.  501  represents  an  elevation,  and  jig.  502  a  plan  of  this  machine. 


It  is  described  by  the  inventor  as  follows  : — The  mineral  from  which  it  is  desired  to  sep- 
arate the  metallic  ore  having  been  crushed  or  pulverized,  is  conducted  through  a  pipe  or 
channel  into  a  revolving  cylindrical  sieve,  a  a.  The  larger  ])art6  pass  into  a  shoot  or  laun- 
der, B,  and  from  thence  into  a  self-acting  jigging  machine.  The  slime  or  fine  portion  passes 
through  the  meshes  of  the  sieve  into  a  shoot,  c,  and  is  discharged  into  an  annular  launder, 
from  whence  it  falls  cither  into  a  stationary  or  revolving  distributor,  d  d.     From  thence  it 


SCO 


ORES,  DRESSING  OF. 


flows  through  guitable  channels  into  the  outer  part  of  the  machine,  e.  The  apparatus  is 
fixed  on  a  perpendicular  axis,  f,  and  is  kept  in  a  continual  oscillatory  motion  by  means  of 
cranks  and  connecting  rods,  g,  the  speed  of  the  cranks  being  adjusted  eo  as  to  keep  the 
slime  in  continual  motion,  and  at  the  same  time  cause  the  ore  to  descend  and  deposit  itself 
at  the  bottom,  whilst  the  waste  or  lighter  portion  is  carried  towards  the  inner  part  of  the 
machine,  where  it  passes  over  a  movable  ring,  h,  which  is  raised  mechanically,  and  in  pro- 
portion as  the  ore  rises  in  the  apparatus.  The  waste  is  discharged  through  the  outlet  i,  and 
conveyed  away  in  launders.  When  the  machine  is  filled  with  ore,  it  can  be  settled,  as  in 
the  dolly  machine,  by  means  of  percussive  hammers,  j  j.  The  ore  can  be  collected  either 
by  reversing  the  gear  and  lowering  the  ring  H,  or  it  may  be  washed  into  a  receiver  as  con- 
venient. 


502 


Motion  is  given  to  the  vertical  bar  k,  which  Is  made  to  vibrate  so  as  to  turn  by  means 
of  a  ratchet  the  wheel  i.,  fitted  on  a  horizontal  shaft,  m.  The  ratchet  is  raised  or  lowered 
by  a  worm  screw,  in  order  to  increase  or  decrease  the  speed  rendered  necessary  by  the  qual- 
ity of  ore  operated  upon.  On  the  horizontal  shaft  m  is  a  worm  pinion,  that  works  a  wheel 
on  a  perpendicular  shaft,  N,  on  which  is  fixed  a  second  worm  pinion,  raising  or  lowering  the 
tooth  segment  on  the  end  of  the  beam  o.  This  segment  ^an  be  shifted  out  of  gear.  The 
opposite  end  of  the  beam  o  is  attached  to  the  rod  p,  ami  connected  with  the  cross-bar  r,  as 
also  with  the  ring  h,  which  has  a  reciprocatory  motion  in  the  centre  of  the  perpendicular 
shaft  F. 

From  the  foregoing  description  it  would  appear  that  Mr.  Borlase  has  combined  in  this 
apparatus  the  principles  of  the  round  buddle  with  that  of  the  dolly  tub. 

In  the  year  1857,  Herr  Von  Sparre,  of  Eisleben,  Prussia,  patented  four  machines  for 
separating  substances  of  different  specific  gravities,  in  all  of  which  water  is  employed,  either 
;is  a  medium  throiigh  which  the  said  substances  fiill  under  the  action  of  gravity,  or  as  an 
ai^'cnt  for  facilitating  the  motion  of  portions  of  the  said'suljstances  along  inclined  surfaces. 
The  particulars,  together  with  illustrations,  will  be  found  in  patent  No.  1405  for  the  year  1857. 

The  mechanical  preparation  of  tin  and  copper  ores  has  from  time  to  time  been  noticed 
by  several  writers.  In  1758  Borlase  described  the  method  employed  in  the  west  of  Corn- 
wall. Twenty  years  later.  Price,  in  his  Mincralogia,  added  to  Borlase's  description,  and 
illustrated  some  of  the  apparatus  then  in  use.  Afterwards  Dr.  Boase  published,  in  the 
second  volume  of  the  Ti-ansactiona  of  the  GcoJorfiral  Sociefi/  of  Cornii'nll^  an  article  »ipon 
the  dre.'^sing  of  tin  in  St.  Just.  In  Vol.  IV.  Mr  W.  Jory  Henwood  inserted  a  paper  on 
dressing ;  and  some  general  remarks  will  be  found  on  the  subject  in  De  la  Bechc's  Report 
on  the  Geolocii/  of  Cornwall.  The  enrichment  of  lead  ores  has  been  noticed  by  Forster,  in 
his  Section  of  Mineral  Strata ;  also  by  Warington  W.  Smyth,  in  his  memoir  On  the  31ines 
of  f'orflif/anxhi.rc,  in  the  second  volume  of  the  Memoirs  of  the  Geolor/ical  Survey  of  Great 
Brilah'. 


ORES,  DRESSING  OF. 


8GI 


In  France,  Dufrenoy  and  Elie  de  Beaumont,  Coste,  Perdonnet,  and  Moissenet,  have 
treated  on  the  mechanical  enrichment  of  copper  and  tin  ores.  The  latter  gentleman  visited 
this  country  in  1857,  and  subsequently  gave  the  results  of  his  observations  in  a  highly  in- 
teresting memoir,  entitled  Preparation  du  Mineral  cCitain  daiis  le  Cornwall.  Too  much 
attention  cannot  be  given  to  this  section  of  mining  economics,  for  with  the  increasing  pro- 
duction of  ores,  especially  of  ores  of  low  produce,  and  the  ill-adapted  machinery  oftentimes 
employed,  the  loss  in  concentrating  them  is  an  item  of  most  serious  moment,  any  reduction 
of  which  will  be  so  much  positive  gain  to  the  country. 

In  this  paper  we  have  included  those  machines  which  have  been  long  employed  in  our 
metalliferous  mines — many  of  them  having  been  proved  by  experience  to  be  most  econom- 
ical— together  with  such  of  the  modern  introductions  as  appear  to  promise  the  most  advan- 
tage, and  some  suggestions  which  cannot  but  be  valuable,  since  the  principles  involved  are 
founded  upon  the  universal  laws  of  gravitating  power,  as  applied  to  solids  and  fluids  in 
motion. 

The  Strake,  Tye,  and  Strip. 

These  appliances  may  be  considered  modifications  of  each  other.  Instead  of  effecting 
a  separation  by  relying  upon  subsidence  according  to  the  specific  gravity  of  the  substances, 
they  are  mechanically  impelled  against  a  volume  of  water  so  regulated  as  to  carry  off  the 
lighter  particles. 

Fig.  503  represents  a  ground  plan  of  a  strake  employed  in  the  lead  mines  of  Wales. 

503 


Its  extreme  length  is  about  18  feet,  width  3  feet.  The  top  increases  from  18  inches  to  2 
feet  9  inches  wide.     It  is  constructed  of  wood,  the  bottom  being  covered  with  sheet-iron. 

The  tye  is  usually  20  feet  long,  2^  feet  wide,  and  is  often  employed  for  cleaning  hutch- 
work.  In  some  instances  when  the  ore  or  dradge  is  very  rich,  it  is  crushed  and  then  tyed 
into  heads,  middles,  and  tails,  the  first  portion  going  to  pile,  the  middles  re-tyed,  and  the 
tails  treated  as  refuse  or  washed  in  the  buddle. 

Fig.  504,  A,  inflow  of  water ;    b,  head  of  tye  ;    c,  partition  board.     The  stuff  is  intro- 


505 


?^r^ 


duced  into  the  cistern  d,  flows  over  the  inclined  front  e,  and  is  broomed  at  f.  Between  k 
and  G  are  the  heads,  from  g  to  ii  middles,  h  to  i,  tails.  At  k  is  an  outlet  launder  regulated 
with  a  flood  shut.     An  outline  plan  of  the  tye  is  shown,  fg.  505, 

The  strip  also  consists  of  a  wooden  box 
with  its  bottom  inclined  at  a  greater  or  less 
angle,  in  order  to  suit  the  character  of  the  stuff 
to  be  operated  upon.  The  object  of  this  appa- 
ratus is  somewhat  analogous  to  the  separating 
l)Ox,  viz.,  to  deprive  the  ore  of  the  fine  parti- 
.cles  with  which  it  may  be  associated,  and  there- 
by to  enrich  it  for  subsequent  treatment.  A  rather  strong  stream  of  water  is  emplovoii, 
against  which  the  mixed  mineral  is  violently  projected  by  means  of  a  shovel.  When  ores 
are  strong  and  clean  in  their  grain,  but  little  loss  can  occur  from  this  process,  provided 
proper  care  be  exercised  in  conducting  it ;  but  if  tlicir  structure  be  delicate  and  the  constitu- 
ents intimately  mixed,  the  wastage  must  necessarily  be  groat. 

The  ilhistration,  ////.  506,  shows  a  strip,  cofer,  and  settling  cistern,  with  filtering  appa- 
ratus contrived  for  load  ore.  a,  vertical  launder  C  inches  square,  delivering  water  into  the 
box  D,  9  inches  long  by  26  inclies  wide  at  the  point  c ;    d,  bottom  of  strip  covered  with 


802 


ORES,  DRESSING  OF. 


sheet-iron,  6  feet  long  and  16|-  inches  wide  at  e.  At  this  point  a  ledge  of  wood  is  some- 
times introduced  for  the  purpose  of  modifying  the  velocity  of  the  water  and  forming  a  kind 
of  shallow  reservoir,  so  as  to  allow  the  workman  to  stir  the  stuff.  At  the  end  of  the  strip 
a  cofer,  f,  is  fixed,  1 1  inches  deep,  30  inches  square ;  h,  settling  box,  6  feet  long  and  30 
inches  deep  ;  k,  outlet  for  waste  water.     At  G  is  inserted  a  filtering  launder,  13  inches  deep, 


extending  across  the  cistern.  At  J  a  similar  launder  is  placed,  about  9  indies  dee[i.  The 
water  comes  in  at  a,  is  lodged  in  cistern  b,  flows  smoothly  over  the  feather-edged  board  c, 
falls  into  d  ;  here  the  orey  matter  is  exposed  to  its  action,  a  portion  settles  in  f,  the  Jlorrin 
and  other  light  waste  then  descends  through  g,  depositing  itself  in  the  box  n  ;  and  to  retain 
the  valuable  products  as  much  as  possible,  it  is  filtered  at  j,  through  a  perforated  plate  cov- 
ering the  bottom  of  the  launder.  In  stiipping,  care  must  be  taken  to  regulate  the  overflow 
of  water  at  c  ;  rough  stuff'  must  be  subjected  to  a  stronger  current  than  finer  matter,  and 
the  bottom  of  the  strip  should  be  constructed  with  a  greater  inclination.  In  some  lead 
mines  the  buddle  and  hutch-work  is  stripped  to  be  re-jigged,  whilst  the  stuff  resulting  from 
the  filtering  box  is  hand-buddled  until  sufficiently  enriched  for  the  dolly.  When  ore  is 
associated  with  a  heavy  matrix,  and  the  grain  breaks  into  a  lesser  size  than  the  other  par- 
ticles, the  stripping  may  be  performed  by  inversion,  that  is,  to  wash  the  orey  product  into 
the  cover  and  filtering  hutch,  retaining  the  worthless  portions  at  d. 

The  flat  buddle.  Jig.  507,  is  a  modification,  peculiar  to  the  Welsh  mines,  of  the  inclined 

plane,  and  different  from  all  others  in  its 
507  great  proportional  breadth,  as  well  as  its 

very  trifling  inclination. 

The  stuff'  is  placed  in  a  small  heap  on 
one  side  of  the  supply  of  water,  and  drawn 
with  a  hoe  partly  against  and  partly  across 
the  stream  to  the  other  side  of  the  buddle, 
losing  in  its  passage  all  the  lighter  parts. 
A  heap  of  ore  treated  in  this  manner  may 
be   deprived   of  a  portion  of  blende   and 
pyrites,  minerals  which  from  their  high  specific  gravity  may  have  resisted  previous  opera- 
tions,    a,  platform  of  boards  inclined  two  and  a  half  inches  in  seven  feet;  b,  catch-pit  two 
feet  deep.     The  width  of  this  buddle  varies  from  ten  to  twelve  feet. 

Lisburnc  Machiyic. — This  apparatus  was  invented  by  the  agents  of  the  Lisburne  Mines, 
Cardiganshire,  and  has  been  most  successfully  employed  in  separating  blende  from  lead  ores. 
F'kj.  508  represents  an  elevation,  and  fg.  509  a  ground  plan  of  this  machine,     b,  rakes  or 


ORES,  DKESSING  OF.  8G3 

scrapers  set  at  an  ?injilc,  depending  from  rods  having  their  axis  of  motion  on  tlie  arbor  e. 
Tills  arbor,  as  well  as  a  parallel  one,  is  carried  on  I'riction  rollers  o  o',  and  so  braced  to- 
gether as  to  form  a  kind  of  frame,  m,  rod  attached  to  frame,  and  connected  with  water- 
wheel  L.  N,  balance-beam,  counterpoising  the  frame,  and  rendered  necessary  in  order  to 
equahze  the  motion,  p  p',  balance  catches  serving  to  support  the  third  arbor  when  elevated. 
This  arbor  is  also  parallel  to  the  other  two,  but  has  its  position  on  the  top  of  the  guide 
frame  shown  in  the  elevation.  It  passes  immediately  under  the  angle  of  the  L-shaped  rods, 
and  is  mounted  on  friction  wheels.  Its  action  is  as  follows : — When  the  scrapers  have 
nearly  completed  their  ascending  stroke,  this  arbor  is  elevated  by  means  of  the  wedge- 
shaped  projection  on  the  top  of  the  frame,  and  immediately  the  balance  catch  acts  so  as  to 
retain  it  in  this  position  during  the  descending  stroke,  at  the  termination  of  which  the  catch 
comes  in  contact  with  the  projecting  screw  shown  in  the  elevation,  thereby  dropping  the 
scrapers  upon  the  face  of  the  buddle.  Consequently,  in  the  ascending  stroke,  these  scrapers 
plough  the  vein  stuff  against  the  flow  of  the  stream.  The  orey  matter  to  be  operated  upon 
is  introduced  into  the  compartment  shown  on  the  top  of  the  jjlan,  and  by  means  of  the 
diagonal  scrapers  it  is  washed  and  passed  slowly  across  the  table,  the  heavier  portion  being 
delivered  into  the  bin  f,  and  the  lighter  matter  into  the  box  f',  -whilst  the  tails  are  lodged 
in  the  strips  ii  ii.  The  water  employed  in  driving  the  wheel  is  also  used  for  the  buddle ; 
one  portion  of  it  serves  to  introduce  the  ore,  whilst  the  other  is  regularly  diffused  over  the 
surface  of  the  table,  and  washes  the  waste  from  the  stuff.  In  case  the  quantity  of  water  is 
too  large  for  settling  the  residues  flowing  into  the  strips  h  h,  and  connected  with  the  bins 
F  f',  discharge  launders  are  provided  at  g. 

The  table  of  the  buddle  has  an  inclination  towards  the  bins  f  f',  and  catch-pits  ii  h. 
This  machine  makes  about  twelve  strokes  per  minute,  and  may  be  furnished  with  any  num- 
ber of  rakes  With  twenty-two  rakes,  forty  tons  of  stuff  may  be  concentrated  in  ten  hours, 
so  as  to  afford  ore  for  the  deluing  sieve,  whilst  the  blende  will  be  sufficiently  cleaned  for  the 
market.     The  cost  of  this  apparatus  complete  is  about  £30. 

Sand  and  Slime  Dressing  Machinery. 

In  most  mines  a  large  proportion  of  the  ore  is  composed  of  dradgc,  and  has  to  be  brought 
to  a  fine  state  of  subdivision  either  by  the  crushing-mill  or  stamps.  In  this  condition  the 
ore  is  freed  from  sterile  matter,  and  rendered  fit  for  metallurgic  treatment.  A  variety  of 
machines  have  been  invented  and  applied  to  this  division  of  dressing,  in  which  the  leading 
principle  is  to  produce  a  separation  by  subsidence,  according  to  the  density  of  the  sub- 
stances. In  connection  with  this  principle,  the  stuff  is  not  permitted  to  have  a  vertical  fall, 
but  is  traversed  by  a  flow  of  water,  on  a  table  or  bed  set  at  such  an  angle  to  the  horizontal 
plane  as  may  be  found  expedient.  With  extremely  fine  stuff  apparatus,  including  botii  of 
these  features,  are  sometimes  subjected  to  a  mechanical  jar  or  vibration,  so  as  to  loosen  and 
eject,  as  it  were,  the  worthless  matter  with  which  it  may  be  charged.  In  concentrating 
crushed  or  stamped  ore,  a  certain  quantity  will  often  exist  in  a  very  miimte  state  of  division, 
unable  to  withstand  the  currents  and  volume  of  water  necessary  for  the  separation  of  the 
larger  particles. 

The  amount  and  richness  must  necessarily  depend  upon  the  united  produce  and  charac- 
ter of  the  ore,  as  well  as  the  mode  of  treatment  observed.  A  good  dresser  will  form  as 
little  slime  as  possible,  since  when  the  ore  is  brought  to  this  condition  it  is  usually  associated 
with  a  large  mass  of  worthless  matter ;.  and  not  only  so,  but  the  expense  of  extracting  it  is 
materially  increased.  The  loss  under  the  most  favorable  manipulation  is  very  large,  whilst 
tlic  machinery  requisite  is  probably  more  complicated  and  expensive  than  any  other  section 
of  the  dressing  plant.  Although  several  machines  are  illustrated  under  this  head,  and  many 
more  might  have  been  added,  it  does  not  follow  that  they  may  be  advantageously  employed 
for  every  variety  of  ore. 

Thus  an  apparatus  which  would  enrich  slimes  by  one  operation  from  H  to  5  per  cent., 
might  be  both  economical  and  desirable  for  treating  copper  ore,  Imt  would  not  be  so  impor- 
tant in  the  case  of  lead  ore  of  the  same  tenure  ;  for  after  deducting  the  loss  of  metal  inci- 
d'Mit  to  the  enrichment,  charging  the  manipulative  cost  on  the  full  quantity  of  stuff,  and 
estimating  the  rel.ative  value  of  the  two  products,  it  might  be  found  that  one  would  scarcely 
leave  a  margin  of  gain,  whilst  the  other  would  yield  a  satisfactory  profit. 

The  proper  sizing  of  slime  is  as  necessary  as  in  the  case  of  coarser  work,  and  for  this 
purpose  Captain  Isaac  Richards,  of  the  Devon  Consols  Sline,  has  arranged  a  peculiar  slime- 
j)it.  The  water  and  stuff  from  the  slime  separated,  are  delivered  through  a  launder  into  this 
pit,  at  the  head  of  which  is  fixed  a  slightly  inclined  i)lank,  divided  itito  chaimcls  by  slips  of 
wood  set  in  a  radial  direction  from  the  aperture  of  the  delivery  launder.  This  pit  has  the 
form  of  an  inverted  cone,  and  since  the  water  passes  through  it  at  a  very  slow  rate,  the 
more  valuable  and  heavier  matters  will  be  deposited  at  the  bottom.  This  apparatus  thus 
becomes  not  only  a  slime-pit,  but  also  a  slime-dresser. 

The  ordinary  slime-pit  has  u.sually  vertical  sides  and  a  flat  bottom  ;  the  slime  and  water 
enter  it  at  one  of  its  ends  by  a  narrow  channel,  and  leave  from  the  other  by  the  same 
means. 


8(J-i 


OEES,  DEESSING  OF. 


A  strong  central  current  is  thus  produced  through  the  pit,  whicli  not  only  carries  with  it 
a  portion  of  valuable  slime,  but  also  produces  eddies  and  counter-currents  towards  the  sides 
which  have  the  etibct  of  retaining  matters  which  from  their  small  density  should  have  been 
rejected. 

The  improved  pit,  Jig.  510,  receives  its  slimes  from  the  divided  head  b,  and  lets  a  por- 


tion of  them  off  again  at  c,  whilst  the  richer  and  heavier  matters,  which  fall  to  the  bottom 
of  the  arrangement,  escape  through  the  launder  d,  and  are  regulated  by  means  of  the  plug 
A,  and  the  regulating  screw  a'. 

At  Devon  Consols  the  slimes  flowing  from  the  launder  d  are  directly  passed  over  Brun- 
ton's  machines,  but  instead  of  these  sleeping  tables  may  be  employed. 

In  many  cases  sand  and  slime  stuff  are  much  commingled  with  clay,  and  require  to  be 
broken  and  disintegrated  before  the  ore  can  be  extracted.  A  method  for  accomplishing 
this  is  shown  in  Jig.  511.     a  is  the  circumferential  line  of  a  round  buddle  ;  B,  launder  lead- 

511  /) 


#-NH^l^ 


ing  to  such  buddle,  or  any  other  enriching  apparatus  ;  c  ,  sifting  trommel ;  d,  rotating  pad- 
dles ;  E,  tormentor  ;  f,  driving  shaft. 

A  modification  of  this  method  is  found  in  the  slime  trommel,  fig.  512.     a,  hopper,  into 


612 


■/vvvvvvvvvvj;/ 
7V777777777777 


-r-.^A  — 1.1    '^^-^-^l.,! 


ORES,  DRESSING  OF. 


805 


which  slimes  :ire  lodged  ;  b,  launder,  delivering  clean  water  into  hopper  a  ;  c,  trommel  of 
sheet-iron,  fitted  in  the  interior  with  spikes  for  the  purpose  of  dividing  the  stuff;  d,  disc, 
perforated  to  prevent  the  passage  of  pieces  of  chips  or  bits  of  clay  and  stone  ;  e,  Archime- 
dian  pipes  fitted  into  a  disc  of  sheet-iron,  conveying  water  into  gauze  or  perforated  trom- 
mel F ;  G,  slime  cistern  ;  h,  cistern  for  receiving  the  rough  stuff;  j,  slime  outlet,  communi- 
cating with  round  huddle,  or  other  suitable  apparatus ;  k,  outlet  for  trommel  raff,  which 
may  be  delivered  to  a  sizing  cistern.  The  speed  of  the  gauze  trommel  for  fine  slimes  varies 
from  80  to  100  feet  per  minute. 

Hand  Buddie. — This  apparatus  is  somewhat  extensively  employed  in  lead  mines  for  the 
concentratiou  of  stuff  which  contains  but  a  small  proportion  of  ore,  such  as  middles  and 


513 


tails  resulting  from  the  round  buddle,  or  the  tails  from  strips,  &c.  A  rising  column  of  water 
is  shown  at  a.  This  flows  into  a  trough  b,  and  through  peg-holes  into  c.  Here  the  stuff'  to 
be  treated  is  introduced,  and  continually  agitated  by  the  boy  in  attendance.  The  finer  por- 
tion passes  through  the  perforated  plate  at  d,  and  is  distributed  by  the  fan-shaped  incline  E 
in  a  uniform  sheet  on  the  head  of  the  buddlef.  A  boy  stands  just  below  the  higher  line  of 
middles  with  a  light  wooden  rake  ;  with  this  instrument  he  continually  directs  the  descend- 
ing current  to  the  head  of  the  buddle,  and  by  this  means  succeeds  in  separating  a  larger 
proportion  of  the  ore  than  would  otherwise  be  done.  Whether  the  rake  or  the  broom  be 
employed,  it  is  found  that  some  of  the  fine  lead  is  jlorrined  to  the  extreme  tail  of  the 
buddle.  In  order  to  prevent  this,  the  frame  G  has  been  introduced.  It  is  strained  with 
canvas,  and  always  floats  on  the  flooded  water.  This  canvas  retains  the  fine  lead,  w4iich 
is  from  time  to  time  washed  off  in  a  cistern  of  water.  The  section  to  the  first  dotted  line 
shows  the  heads  of  the  buddle  ;  from  this  to  the  second  dotted  line  will  be  the  middles,  and 
from  the  second  dotted  line  the  tails  commence.  It  must,  however,  be  remarked,  that  the 
exact  line  of  heads,  tails,  and  middles,  must  depend  upon  their  relative  richness.  The 
wooden  rake  is  undoubtedly  preferable  to  the  broom,  as  will  appear  from  the  following  ex- 
periment made  at  the  Swanpool  Mines,  every  thing  being  equal  in  both  trials. 
Stuff  operated  upon  ;  tails  from  washing  strips  assayed  13  per  cent. 

With  Broom.  With  ■Eake. 

No,  1.   Heads,  assayed  -         -         -       167o         -         -         -       20% 

2.  Middles,  ditto  -         -         -         -         4f  .         .         .         sj 

3.  Tails,       ditto  -         -         -         -         4J  -         -         -         1^ 

It  would  be  found  a  great  improvement  if  these  buddies  were  arranged  so  as  to  have 
their  bottoms  elevated  when  it'might  be  necessary.  As  they  are  fitted  at  present,  the  angle 
at  tiie  head  is  a  constantly  increasing  one.  The  result  is,  the  heads  become  poorer  and  the 
tails  richer,  provided  the  fixed  inclination  of  the  buddle  is  correct  at  starting,  as  the  opera- 
tion proceeds.  In  proportion  to  the  poorness  of  the  stuff  the  buddle  should  have  its  width 
increased,  as  well  as  be  made  shallower.  If  the  stuff  be  also  passed  through  a  trommel 
before  entering  the  buddle,  the  result  will  be  found  much  improved. 

The  Round  Buddie  is  said  to  have  been  first  introduced  into  Cardiganshire,  but  has  now 
become  general  in  every  important  mining  district.  This  machine  serves  to  separate  par- 
ticles of  unequal  specific  gravity  in  a  circular  space  inclined  from  the  centre  towards  the  cir- 
cumference. Its  construction  will  be  best  understood  by  reference  to  the  annexed  engrav- 
ing, Ji(i.  514,  in  which  a  is  the  conical  floor,  fornKnl  of  wood,  and  about  18  feet  in  diameter, 
'on  which  the  stuff  is  distributed  ;  b  is  a  cone  supporting  the  upper  part  of  the  apparatus, 
and  serving  to  effect  the  equal  distribution  of  the  orey  matter,  d  is  a  wheel  for  giving  mo- 
tion to  the  arrangement ;  e,  a  funnel  lunf'orated  with  four  holes  and  furnished  at  top  with  an 
annular  trough  ;  f  f  are  arms  carrying  two  brushes  balanced  by  the  weights  G  G  ;  H  is  a 
launder  for  conducting  the  stuff  from  the  pit  i  ;  k  is  a  receptacle  in  which  the  slimes  mixed 
with  water  arc  worked  up  in  suspension  by  the  tormentor,  which  is  a  wooden  cylinder  pro- 
vided with  a  number  of  iron  spikes  ;  l  is  a  pulley  taking  its  motion  from  a  water-wheel,  and 
Vol.  III.— 55 


866 


ORES,  DRESSING  OF. 


M  a  circular  sieve  fixed  on  the  arbor  n.      The  stuff  at  K  is  gradually  worked  over  a  bridge 
forming  one  of  the  sides  of  a  catch-pit  between  the  sieve  M  and  the  tormentor,  from  whence 

514 


it  passes  off  into  the  sieve,  by  which  the  finer  particles  are  strained  into  the  pit  i,  whilst  the 
coarser,  together  with  chips  and  other  extraneous  matters,  are  discharged  on  the  inclined 
floor  in  connection  with  the  launder  o.  From  the  pit  i  the  stuff  flows  by  the  launder  n  into 
the  funnel  e,  and  after  passing  through  the  perforations  flows  over  the  surface  of  the  fixed 
cone  B,  and  from  thence  towards  the  circumference,  leaving  in  its  progress  the  heavier  por- 
tions of  its  constituents,  whilst  the  surface  is  constantly  swept  smooth  by  means  of  the  re- 
volving brushes.  By  this  means  the  particles  of  different  densities  will  be  found  arranged 
in  consecutive  circles.  The  arms  usually  make  from  two  and  a  half  to  four  revolutions  per 
minute,  and  a  machine  having  a  bed  18  feet  in  diameter  will  work  up  from  15  to  20  tons 
of  stuff  per  day  of  ten  hours. 

Oennan  Rotating  Bxddle. — This  machine  is  said  to  effect  the  separation  of  the  earthy 
matters  from  finely  divided  ores  more  readily  than  the  ordinary  round  huddle.  For  this 
purpose  the  pulverized  ore  is  introduced  near  the  centre  of  a  large  slightly  conical  rotating 
table,  and  flowing  down  towards  its  periphery  a  portion  of  the  upper  part  or  head  becomes 
at  once  freed  from  extraneous  substances.  Beyond  this  line  of  separation  in  the  direction 
of  the  circumference,  the  stuff  is  subjected  to  the  action  of  a  series  of  brushes  or  rakes,  and 
by  means  of  a  sheet  of  water  flowing  over  the  agitated  slimes,  clean  ore  is  stated  to  be  pro- 
duced almost  at  a  single  operation. 

The  illustration,  fff.  515,  represents  this  machine  as  first  erected  at  Clausthal,  but  it  may 

515 


be  remarked  that  some  of  its  mechanical  details  have  been  since  judiciously  modified  by 
Mr.  Zenner  of  Newcastlc-on  Tyne.  a  is  an  axis  supporting  and  giving  motion  to  the  table 
c,  10  feet  in  diameter,  and  rising  towards  the  centre  1  inch  per  foot;  r,  cast-iron  wheel  15 
inches  in  diameter,  0])crated  on  by  the  tangential  screw  n.  The  tooth-wliecl  f  drives  flie 
pinion  f,  the  axis  of  whicli  is  provided  witli  a  crank  giving  motion  to  a  rod  fitted  with 
brushes;  o  is  an  annular  receiving-box  4^  indies  wide,  and  6  inches  deep;  a,  circular 
trough  of  sheet-iron  supported  on  the  axis  of  the  table  an  iiu-h  or  two  above  its  surface,  am! 
so  divided  that  one  quarter  of  it  serves  for  the  reception  and  equal  distribution  of  the  slime, 
whilst  the  other  three-quarters  supply  clear  water ;  b,  launder  for  supplying  slime  ore,  lie- 
hind  which  is  another  not  shown,  for  bringing  in  clear  water.  o,  trough  supplying  addi- 
tional water  to  the  stuff  agitated  by  the  bruslies.  One  end  of  this  water-trough  is  fixed 
about  the  middle  of  the  table,  whilst  the  other  advances  in  a  curved  direction  nearly  to  the 
circumference. 

77/e  Concave  Sli?ne  Buddie. — The   object  of  this  apparatus  is  to  concentrate  on   the 
periphery  of  the  floor,  instead  of  the  centre.     This  arrangement  gives  an  immense  working 


ORES,  DRESSING  OF. 


8G7 


area  for  the  heads,  and  at  the  same  time  admits  of  the  separation  of  a  greater  portion  of  the 
waste  than  can  be  effected  by  tlie  ordinary  round  buddle.  After  the  slimy  water  has  been 
discharged  on  the  edge,  the  area  over  which  it  has  to  be  distributed  is  gradually  contract- 


51G 


'¥£M/y'  y^/!'///////^' 


ing,  thereby  increasing  the  velocity  of  the  flow,  and  enabling  it  to  sweep  off  a  proportion- 
ate quantity  of  the  lighter  matter  associated  with  the  ore.  a  represents  the  inflow  slime 
laimder ;  6,  a  separating  trommel,  through  which  the  slimes  pass  previous  to  their  entrance 
into  the  launder  a.  C,  outlet  launder,  for  taking  off  castaways ;  ^,  arbor  giving  motion  to 
the  buddle  arms  and  diagonal  distributing  launders  attached  thereto  held  by  the  braces 
10  w' ;  e,  bevel  wheel  on  driving  arbor;  /",  dowm-ight  launder,  to  which  is  affixed  a  regu- 
lating cock.  A',  for  supplying  slimes  to  trommel ;  /;,  hiuiider  for  delivering  clean  water  to 
circular  box  m,  and  which  water  passes  through  slot  openings  at  ;>  ;;,  uniting  with  and  lliin- 
ning  the  slimy  matter  previous  to  its  passing  into  the  diagonal  delivery  launders;  /',  circu- 
lar pit  for  receiving  tailings.  Attached  to  the  wooden  bar  x  is  a  piece  of  canvas  with  cor- 
responding pieces  depending  in  a  similar  manner  from  each  arm,  and  which  serve  to  give 
an  even  surface  to  the  stuff  in  their  rotation.  The  slimes  flow  from  four  diagonal  launders, 
each  having  its  upper  end  in  communication  with  box  /.  The  speed  of  the  arms  an<l  diago- 
nal launders  must  vary  with  the  nature  of  the  stuff  to  be  operated  upon  ;  for  rough  sands 
eight  revolutions  per  minute  have  been  found  sufficient,  but  for  fine  slimes  from  fourteen  to 
sixteen  revolutions  in  the  same  time  are  necessary.  The  inflow  of  slime  and  water  should  also 
be  proportioned  to  the  speed  and  density  of  the  stuff  to  be  treated.  No  precise  instruc- 
tions can  be  offered  on  this  head,  but  an  experienced  dresser  would  easily  determine  the 
proportions  after  a  few  trials.  The  bed  is  eighteen  feet  diameter,  and  has  a  df'clination  of 
about  six  inches  from  the  edge  to  the  point  where  it  unites  with  the  horizontid  portion  of 
the  floor.  The  cost  of  this  apparatus  complete  is  about  £15.  It  is  employed  to  a  consider- 
able extent  in  Prussia,  and  affords  highly  satisfactory  results. 

Experiment  on  slime  ore,  very  fine  and  much  intermixed  with  carbonate  of  iron  : — 
Produce  before  entering  buddle     -         -         -       C  per  cent. 
Iha.h  of  bud.lle  averaging  3  inches  deep  and  \  ^     „,   ^^^  .^  ^^  ^^  ^^^^^^         ^^^^  ^f  ,^^^,, 

22  inches  wide         -----  j       -i  '"  ' 

Middles  of  buddle  averaging  IJ  inches  deep  [    g,o/        ,  ^o  qj,  "  "  " 

and  18  inches  wide-         -         -         -         .  j      ^"' ' 
Tails  of  l)uddle  averaging  |  inch  deep  -         -       3%  and  55^3  oz.  of  silver  per  ton  of  lead. 
Castaways    -.--.--       ^"'g 

Time  required  to  fill  buddle,  3  hours  ;  nmiiber  of  arms  in  buddle,  i  ;  number  of  revo- 
lutions of  arms  per  minute,  8. 

Expm'iment  on  fine  slimes,  much  associated  with  carbonate  of  iron  : — 

Produce  before  entering  the  buddle        .--.--;■!  °/o 

Jlead-i  -i  inches  deep,  16  inches  wide 7^% 

Middles      U        do.  12        do. 1  °/o 

Tails  -         -         -         -         - -      traces. 

Number  of  revolutions  of  arms  per  minute,  14  ;  time  required  to  fill  buddle,  Ti  linur.i. 


868 


ORES,  L'RESSIXG  OF. 


In  working  this  biiddle  one  month  upon  the  fine  and  rough  slimes,  indicated  in  the  twd 
foregoing  experiments,  the  results  obtained  were  :  — 

Mean. 

Assay  of  stuff  before  entering  the  buddle 5u-"/o 

Heads  afforded 12-5 

Middles 5-0 

Tails 0-77 

Experiment  on  slime  ore  containing  1i  per  cent,  of  lead  : — 

In  12  hours  4  tons  were  washed,  and  gave  14  cwts.  of  crop,  28  cwts.  middles,  12  cwts. 
tails,  and  26  cwts.  of  waste.  The  14  cwts.  of  crop  were  washed  in  3  hours,  and  afforded 
3|  cwts.  dressed  slime  ore,  5^  cwts.  of  middles,  4  cwts.  of  tails,  and  1  cwt.  of  castaways. 
The  middles  resulting  from  both  operations,  viz.,  33^  cwts.,  were  washed  in  8  hours,  and 
gave  crop  4  cwts.,  middles  12  cwts.,  tails  4  cwts.,  and  waste  13^  cwts.  The  tails  were  now 
washed  in  3  hours,  and  afforded  4  cwts.  of  middles  and  12  cwts.  of  castaways.  16  cwts. 
of  middles  were  also  washed  in  3  hours,  and  furnished  2  cwts.  crop,  6  cwts.  middles,  and  8 
cwts.  of  castaways.  In  addition,  10  cwts.  of  crop  ore  were  washed  during  3  hours,  and 
gave  l''/io  cwt.  of  slime  ore,  crop,  1  cwt.,  middles,  6  cwts.,  castaways,  1  cwt. 

The  results,  therefore,  show  that  four  tons  of  rough  slimes  were  washed  in  32  hours,  and 
afforded  5^  cwts.  slime  ore  at  43i  per  cent.,  leaving  1  cwt.  of  crop  at  31  per  cent.,  and  12 
cwts.  of  middles  yielding  4;^  per  cent.  A  comparison  was  also  made  with  the  shaking  table ; 
5  tons  of  the  same  slimes  were  washed  in  48  hours,  and  gave  7  cwts.  of  dressed  ore,  1  cwt. 
of  heads,  and  8  cwts.  of  middles. 

The  following  are  the  results  of  an  experiment  made  between  the  concave  buddle  and 
the  ordinary  round  buddle,  time  occupied,  24  hours : — 


Pounds. 

Water. 
AYeicht 
per  cent. 

Dry 

"Weiglit. 

Lead. 

Blende. 

Assay 
per  cent. 

Total 

Assay 
per  cent. 

Total. 

Quantity  of  slimes   to 
each  buddle     - 

Obtained  from  concave 
buddle  : — 
Cro])s 
Middles   -        .        . 

Total 

Obtained    from    round 
buddle: — 
Crops       ... 
Middles    -         -         . 

Total 

Loss  by  concave  buddl 
do.      round         do. 

4262 

23i 

3268 

8-7 

284-5 

34-33 

1121-5 

505 
1350 

510 
2530 

e    - 

15-4 

25-7 

24-8 
39-9 

427 
1003 

1430 

23-6 
7-6 

10-2 

7-86 

10 
12 

100-8 

77-7 

36-65 
37-0 

34-64 
27-59 

155-6 

371-0 

178-5 

526-6 

383-5 
1521-0 

39- 
119-5 

133-4 
419-6 

1904-5 

158-5 

6- 

5-9       - 

{ 

I 

553-0 

- 

)94-0 
)68-5 

The  tails  lying  upon  the  horizontal  part  of  concave  buddle  contained  27^  per  cent,  of 
zinc  and  24-  per  cent,  of  lead. 

It  will  be  perceived  that  the  much  larger  crop  from  the  concave  buddle  was  more  than 
twice  as  rich  for  lead,  whilst  it  was  only  2  per  cent,  richer  for  zinc. 

Quartzose  ore  without  blende  was  then  tried,  and  a  similar  weight  gave  1,570  lbs.  of 
crop,  affording  56+  per  cent.,  or  88Si^  lbs.  of  lead,  and  3,450  lbs.  of  middles,  of  14  per 
cent,  produce,  equal  to  483  lbs.  of  lead,  or  together  5,020  lbs.  of  stuff",  containing  1,372  lbs. 
of  lead.  The  round  buddle,  on  the  contrary,  gave  455  lbs.  of  crop  ore,  of  63^  per  cent., 
equal  to  290  lbs.  of  lead,  2,910  lbs.  of  middles,  of  18^  per  cent.,  representing  541  lbs.  of 
lead,  or  a  total  of  3,365  lbs.  of  stuff",  containing  831  lbs.  of  lead. 

Mf/.  517  represents  a  buddle  arranged  for  the  treatment  of  fine  slimes,  and  which  has 
been  found  to  yield  highly  satisfactory  results  at  several  mining  establishments  in  Prussia 
where  it  has  recently  been  introduced.  It  is  entirely  constructed  of  metal,  and  every  part 
is  carefully  fitted  in  order  to  secure  an  even  and  delicate  action.  The  stuff"  is  introduced 
into  the  hopper  a,  from  whence  it  passes  into  the  trommel  n,  turned  by  the  band  c.  The 
fine  stuff  passing  through  the  perforated  cylinder  n,  falls  upon  tlie  shoot  f,  and  flows  upon 
the  concave  table  e.     This  table  revolves  in  the  direction  of  the  arrow,  and  acquires  its 


OKES,  DRESSING  OF 


869 


motion  by  means  of  the  strap  g  driving  the  tangent  wheel  and  screw  shown  at  H.  Concen- 
tric with  the  table  a  wrought-iron  pipe,  i,  is  fixed,  which  is  pierced  with  numerous  small 
holes.     The  quantity  of  water  to  this  pipe  is  adjusted  by  the  regulating  cocks  j  i'  i"      ^''• 


Be- 


neath the  table  is  a  circular  receptacle  or  bottom,  k,  having  three  compartments  for  receiv- 
ing the  washed  stuff.  From  a  io  d  the  jets  of  water  are  comparatively  light ;  from  d  to  c 
the  force  of  water  is  increased,  and  still  further  augmented  in  that  portion  of  the  circle 
extending  from  c  to  o,  whilst  from  o  to  x  it  is  sufficiently  powerful  to  clean  the  buddle.  In 
each  of  the  sections  a  portion  of  waste  along  with  a  little  light  ore  is  washed  into  the  recep- 
tacles underneath,  from  whence  it  may  flow  into  strips  or  buddies  for  further  separation,  or 
is  otherwise  manipulated  upon  a  second  buddle.  The  water  is  supplied  to  the  machine 
under  pressure  by  the  pipe  l.  This  apparatus  will  wash  from  SO  to  100  cubic  feet  of  free 
slimes  in  ten  hours,  or  from  60  to  SO  cubic  feet  of  tough  slimes  in  the  same  period.  Lead 
stuff  affording  4"'o  with  a  light  waste  has  been  enriched  to  40'"o  in  a  second  revolution,  and 
in  a  third  and  fourth  rotation  40"  o  slime  has  been  enriched  so  as  to  yield  60"  o  of  ore.  The 
buddle  table  makes  two  revolutions  per  minute  ;  its  diameter  varies  from  8  to  10  feet,  and 
the  power  required  is  about  one-tenth  of  a  horse  power.     One  boy  can  serve  four  buddies. 

Slime  Tnuiking  Apparatia. — The  illustration  fg.  518  shows  the  apparatus  employed 
in  some  of  the  lead  mines  of  Cardiganshire.  The  slimes  are  lodged  in  the  several  settling 
pools  marked  a,  and  flow  through  the  channels  b.  At  c  the  slimes  pass  into  the  launder  d 
to  the  box  E,  where  they  are  comminuted,  and  from  thence  progress  into  the  trommel  f. 
From  the  circular  cistern  G,  V-shaped  launders  diverge  to  the  trunks  k,  which  are  divided 
by  partitions  i.  Upon  the  axis  j  in  each  buddle  head,  paddles  rotate,  and  flush  the  slimes 
over  a  head  board,  where  a  partial  separation  is  effected.  The  wheel  l  is  driven  by  water 
from  the  pools  a,  and  any  excess  is  carried  off  by  the  launder  x.  At  o  o  two  hand-buddies 
are  shown  ;  these  are  intended  for  the  concentration  of  the  heads  and  middles  produced  in 
the  trunks  K.  The  axis  at  p  is  furnished  with  spikes  for  the  purpose  of  breaking  up  the 
slimes.  After  the  water  has  passed  over  the  wheel  l,  it  flows  into  the  launder  r,  and  from 
thence  into  Q. 

At  the  Minera  lead  mines,  where  the  ore  produced  is  very  massive  and  capable  of  a  high 
degree  of  enrichment,  the  slimes  average  9  per  cent.,  and  are  concentrated,  by  means  of 
this  apparatus,  together  with  a  round  buddle  and  dolly  tub,  to  75  per  cent,  of  metal.  With 
six  trunks,  one  round  buddle,  one  man,  and  four  boys,  about  nine  tons  of  clean  ore  are  ob- 
tained monthly. 

Attempts  have  been  made  by  Brunton  and  others  to  separate  metalliferous  ores  of  dif- 
ferent specific  gravities  by  allowing  them  to  descend  at  regulated  intervals  in  still  water. 
By  reversing  the  operation  and  causing  the  current  to  ascend  uniformly,  the  particles  may 
he-  iTi'ich  more  conveniently  and  accurately  classified.     This  has  been  done  in  a  machine 


870 


OKES,  DRESSING  UF. 


designed  by  the  late  Mr.  Herbert  Mackworth.  Suppose  a  funnel-shaped  tube,  larger  at  the 
top ;  nitl)  a  current  of  considerable  velocity  flowing  upwards  through  it,  grains  of  equal 
size  of  galena,  pyrites,  and  quartz,  when  thrown  in,  will  be  suspended  at  ditierent  heights, 


1 

1 1 

<? 

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518 


depending  on  the  velocity  of  the  current  at  each  heiglit.  Tlius  culiical  grains  of  galena, 
iron,  pyrites,  and  quartz,  of  '12  inch  diameter,  will  be  just  suspended  by  vertical  currents 
moving  at  velocities  of  12  inches,  7  inclies,  and  ."i  inches  linear  per  second  ;  flat  or  oblong 
particles  require  lathcr  less  velocities  to  support  them,  inasmuch  as  they  descend  more 
slowly  in  still  water  than  the  cubical  or  spherical  particles. 

A  sinij)le  form  of  applying  this  principle  is  presented  by  the  vertical  trunks  shown  in 
,^'<7,'!  519  and  520.  Metalliferous  ore,  after  being  classified  by  .sifting,  or  tin  ore  as  it  comes 
from  the  stamps,  may  be  allowed  to  flow  mixed  with  water  down  the  shoot  a.     The  supply 


ORES,  DRESSING  OF. 


871 


of  water  should  be  taken  from  a  head  so  as  to  be  perfectly  uniform  in  quantity.  The  water 
mixed  with  the  ore  flows  in  the  direction  of  the  arrows  down  and  then  up  the  divisions  b', 
b',  b^,  b",  and  b',  each  of  which  increasing  in  area,  the  velocity  of  the  ascending  current 
diminishes  in  the  same  proportion.     The  particles  of  greatest  specific  gravity  will  be  de- 

519 


posited  in  the  bottom  of  b\  In  the  bottom  of  B"  will  be  found  small  particles  of  great 
specific  gravity  and  large  particles  of  small  specific  gravity.  The  same  relation  will  exist  in 
B^,  B'',  and  B^,  only  the  particles  of  each  will  be  smaller  in  succession.  The  plugs  in  the 
holes  c  c  c,  being  opened  as  is  found  necessary,  allow  the  accumulations  in  the  bottom  of 
each  trunk  to  discharge  themselves  into  separate  troughs.  The  rocking-frame  and  rakes  d  d 
constantly  stir  up  the  sediment  so  as  to  bring  it  under  the  action  of  the  water.  To  produce 
the  oscillation  of  the  rakes,  two  spade-shaped  plates  e  k  are  exposed  to  the  action  of  the 
falling  water  discharged  from  the  end  of  the  box  which  rocks  the  frame  to  and  fro.  The 
ore  in  the  first  trunk  is  fit  for  smelting  ;  the  ore  passing  off"  from  the  bottom  of  the  other 
trunks  is  in  a  very  favorable  condition  for  framing,  or  it  may  be  sifted  to  remove  the  larger 
particles  of  less  specific  gravity. 

2'he  Rack  or  Hand- Frame. — This  is  composed  of  a  frame  c,  Jic/.  521,  which  carries  a 

521 


sloping  board  or  table  susceptible  of  turning  to  the  right  or  left  upon  two  pivots  K  k.  The 
head  of  the  table  is  the  inclined  plane  t.  A  small  board  p,  which  is  attached  by  a  band  of 
leather  l,  forms  a  communication  with  the  lower  table  c,  wiiose  slope  is  generally  5  inches 
in  its  whole  length  of  9  feet,  but  this  may  vary  with  the  nature  of  the  ore,  being  somewhat 
less  when  it  is  finely  pulverized. 

In  operating  with  the  table,  the  slimy  ore,  to  the  extent  of  15  or  20  pounds,  is  place<l 
on  the  head  t,  and  washed  over  l  and  p  O'u  to  the  table ;  then  the  operator  with  a  toothless 
rake  distributes  it  equally  over  the  head,  the  richest  particles  remain  on  the  highest  part  of 
the  table  by  virtue  of  their  greater  specific  gravity,  whilst  the  iiuuidy  water  falls  through  a 
cross  slit  at  the  bottom  into  a  receptacle  b.  When  the  charge  ol"  ore  has  been  thoroughly 
racked,  the  table  is  turned  on  its  axes  k  k  until  it  is  brought  into  a  vertical  position,  and 
tiie  deposit  on  its  surface  is  washed  into  boxes  u'  b".  The  box  b'  will  contain  an  impure 
schlich  which  nmst  be  again  framed,  whilst  b"  will  probably  contain  a  slime  sufficiently  en- 
riched to  be  finished  by  the  dolly  tub. 


872 


ORES,  DRESSING  OF. 


The  slope  of  the  rack  table  for  washing  tin  stufiF  is  Vf  inches  in  9  feet.  The  width  is 
about  4  feet. 

The  average  quantity  of  lead  slime  which  can  be  washed  per  day  of  ten  hours,  is  about 
30  cwt.,  and  the  water  necessary,  say  600  gallons. 

The  general  appearance  of  the  rack  is  shown  in  the  illustration,  f.g.  522.     a,  table  ;  b, 

522 


inclined  plane  upon  which  the  stuff  is  lodged.     Clean  water  flows  over  the  ledge  c.     When 
the  table  a  is  turned  in  a  vertical  position,  the  racking  girl  washes  it  by  depressing  the  lever 
E  attached  to  the  V-shaped  launder  d,  thereby  discharging  the  water  which  it  may  contain. 
The  heads,  middles,  and  tails  are  lodged  in  the  compartments  f,  g,  and  h,  respectively. 
The  Machine  Frame,  Jig.  523,  consists  of  an  inclined  table,  about  8  feet  long,  and  5 


523 


feet  wide,  with  sides  5  inches  high.  At  each  end  are  fixed  axles  of  iron,  a  b,  which  are 
centred  in  two  vertical  pieces  of  timber  c  r,  and  admit  of  the  frame  being  turned  perpen- 
dicularly. At  the  head  of  the  frame  is  a  ledge  p;,  on  which  numerous  lozcnge-shnped  pieces 
of  wood  are  fixed  in  order  to  distribute  the  liquid  stuff  on  the  entire  width  of  the  frame. 

From  the  frame  head,  the  stuff  falls  on  a  sloping  board  f,  which  admits  of  being  turned, 
as  it  is  hung  by  leathern  hinges,  when  the  frame  assumes  an  upright  position.  At  one  of 
the  bottom  corners  of  the  frame  is  a  box  G,  into  which  the  chief  part  of  the  water  from  the 
table  flows.  In  operating  with  this  machine,  the  liquid  matter  is  admitted  to  the  frame 
head  K,  through  the  hole  ii,  and  flowing  in  a  thin  sheet  on  the  table  i,  deposits  the  vein  stuff 
according  to  its  varying  specific  gravity,  the  best  quality  being  heads  from  1  to  2,  the  mid- 
dles from  2  to  3,  whilst  the  tails  are  lodged  at  the  end  of  the  apparatus.  To  the  water 
wheel  is  attached  a  horizontal  axle  fitted  at  given  distances  with  cams,  which  disengage  at 
the  propel  time  parts  of  the  machinery  connected  with  the  frame.     The  first  cam  acts  on 


ORES,  DRESSING  OF. 


873 


the  rod  k,  and  stops  the  flow  of  tin  stuff;  the  second  cam  disengages  a  catch  beneath  the 
displacing  box  g,  containing  the  frame  water,  and  immediately  the  irame  assumes  a  vertical 
position,  striking  in  its  movement  a  catch  at  m,  which  upsets  the  V-shaped  launder  n,  con- 
taining pure  water,  in  such  a  way  as  to  wash  the  ore  on  the  table  into  two  cofers  o  and  p. 
The  frame  then  returns  to  its  horizontal  position,  and  the  orey  matter  is  again  admitted 
through  H.  One  boy  can  manage  twenty  of  these  frames.  When  employed  in  cleaning  tin 
stuff,  the  two  cofers  o  and  p  are  discharged  into  separate  pits  about  15  feet  long,  6  feet 
wide,  and  12  or  15  inches  deep.  The  refuse  from  the  end  of  the  frames,  iis  well  as  the  slimy 
water  from  the  displacing  box,  is  either  thrown  away  or  subjected  to  further  treatment;  the 
cover  0  is  usually  taken  to  the  hand  frames,  after  which  it  is  tossed  and  packed,  whilst  the 
stuff  from  cover  p  is  again  submitted  to  machine  framing. 

Hancock's  Slide  Frame. — The  ores  and  accompanying  waste  are  brought  into  a  state  of 
suspension  by  water,  and  are  then  by  adjustment  made  to  pass  over  a  slight  fall,  so  as  to 
produce  the  greatest  regularity  in  its  flow  over  tables  fixed  upon  a  given  incline,  each  table 
having  a  sufficient  drop  from  the  table  above.  When  the  tallies  are  sufficiently  charged, 
clean  water  is  introduced  to  pass  over  the  charged  table.     The  surfaces  of  the  tables  are 


874 


ORES,  DRESSING  OF. 


subject  to  the  action  of  brushes  or  brooms  during  a  part  or  the  whole  time  of  both  opera- 
tions until  the  ores  are  sulficiently  cleaned.  In  some  cases  the  use  of  such  brushes  or 
brooms  is  dispensed  with.  The  ores  (on  the  tables)  thus  cleaned  are  washed  off  into  cis- 
terns by  the  action  of  water  passing  over  the  surfaces  of  the  tables  after  they  are  raised  to 
nearly  perpendicular  positions. 

Fig.  524  represents,  1,  Iramework  to  carry  the  gear  on  each  side  of  the  machine ;  2, 
the  stretcher  or  pivot  piece  on  which  all  the  tables  are  resting ;  3,  centre  bearings  of  the 
tables,  to  which  is  attached  an  adjusting  screw  for  raising  or  falling  them  ;  4,  a  slide  valve, 
which  admits  or  shuts  oft",  as  required,  the  ores,  which  are  previously  brought  into  a  thin 
consistency  with  water ;  5,  launder  through  which  the  ores  pass  to  the  heads,  which  are 
divided  into  sections  and  numbered  ;  6,  the  ores,  &c.,  dropping  from  the  heads  into  a  laun- 
der, 7,  the  working  edge  of  which  is  made  level  by  an  adjusting  screw  at  each  end  for  the 
ores  to  pass  over ;  8  is  a  stretcher,  passing  over  the  heads  in  both  ends,  bolted  to  1,  from 
which  G  and  7  are  supported  by  three  drop  adjusting  screws  ;  9  are  four  tables  over  which 
the  ores  have  to  pass,  first  receiving  the  deposit  of  the  cleanest  or  best  ores,  and  the  rest  in 
gradation;  10,  the  drop  or  fall  from  one  table  to  another;  11,  the  balance  cistern,  into 
which  the  refuse  from  the  table  passes,  and  when  full,  by  lifting  the  catch  12  it  forms  a  bal- 
ance for  turning  up  the  tables  to  be  washed  down,  each  table  being  connected  with  rods  and 
lever  a  ;  this  done,  such  catch  is  lifted  up,  and  13  forms  a  returning  balance  for  the  tables; 
at  14  a  stream  of  water  is  introduced,  passing  into  15  as  a  receiver ;  on  the  turning  up  of 
the  tables,  valves  16  are  lifted  by  lever  and  rod  17,  and  admit  the  water  into  perforated 
launders  18  to  wash  off  the  ores  into  receivers  19,  through  which  it  passes  out  into  deposit 
hutches.  The  slide  valve  4  having  admitted  a  sufficient  quantity  of  ore,  which  has  been 
deposited  on  the  tables,  is  now  closed,  and  the  valve  20  is  opened  by  the  conductor's  hand 
at  rod  handle  21,  through  which  a  supply  of  water  passes  into  launder  22,  and  flows  over 
the  tables  for  the  purpose  of  cleaning  the  ores.  The  framework  for  the  brushes  23  is  car- 
ried on  four  wheels  24,  each  table  being  supplied  with  a  brush  25,  which  brushes  its  respec- 
tive tables  upwards,  and  on  arriving  at  the  heads  of  the  tables,  the  brushes  being  all 
connected,  are  lifted  by  lever,  and  26  slips  into  the  catch  27,  and  the  brushes  pass  back  over 
the  tables  without  touching  until  the  lever  of  the  catch  is  struck  out  by  28,  and  the  brushes 
drop  again  on  the  tables.  Each  brush  is  adjusted  by  screws  and  carried  on  arbors  running 
across  the  frame.  This  frame  with  its  appendages  is  propelled  by  a  rod  29,  attached  to  a 
beam  30,  that  can  be  worked  by  any  sufficient  power  that  may  be  applied. 

The  ores  passing  from  the  third  and  fourth  tables  through  the  two  lower  receivers  19 
into  a  cistern,  are  lifted  by  a  plunger  b,  attached  to  beam  30,  by  a  rod  31,  and  passes  back 
by  launder  32  to  be  readmitted  into  slide  valve  4,  and  repass  the  tables.  In  11  balance  cis- 
tern is  a  valve  33,  which  on  the  dropping  of  the  table  lets  out  the  contents.  34  is  a  catch 
for  holding  the  frame  and  brushes  during  the  time  of  turning  dowia  and  washing  the  tables. 
The  machine  is  to  be  worked  with  or  without  brushes,  as  the  character  of  the  ores  may  re- 
quire. It  may  be  extended  or  diminished  to  any  number  of  tables,  and  their  size  may  vary 
as  may  be  found  necessary  on  the  same  principle,  c  is  a  wheel  acting  as  a  parallel  motion 
for  the  plunger  pole,  and  running  on  a  bar  of  iron. 

This  machine  was  in  constant  use  at  the  Great  Polgocth  Mine  for  some  time,  and,  it  is 
said,  effected  a  saving  of  30  per  cent,  in  the  dressing  of  slime  ore.  It  is  not  so  well  adapted 
for  rough  as  for  the  treatment  of  fine  slimes ;  the  appauatus  may  be  managed  by  a  boy  at 
%d.  per  day,  and  the  cost  of  the  machine  complete  is  about  £60. 


525 


52P 


Percu.iaion  Table,  or  Stosshcerd. 
— The  diagrams,  figs.  525,  526,  and 
527,  exhibit  a  plan,  vertical  section, 
and  elevation  of  one  of  these  tables, 
used  in  the  Harz.  The  arbor,  or  great 
shaft,  is  shown  in  section  i)erpendieu- 
larly  to  its  axis,  at  a.  The  emus  or 
wipers  are  shown  round  its  circum- 
ference, one  of  them  having  just 
icted  on  n. 


ORES,  DRESSING  OF. 


These  cams,  by  the  revolution  of  the  arbor,  cause  the  alternating  movements  of  a  hori- 
zontal bar  of  wood,  o,  n,  which  strilves  at  the  point  w  against  a  table  d,  b,  c,  u.  This  table 
is  suspended  by  two  chains  t,  at  its  superior  end,  and  by  two  rods  at  its  lower  end.  After 
having  been  pushed  by  the  piece,  o,  «,  it  rebounds  to  strike  against  a  block  or  bracket  b. 
A  lever  p,  q,  serves  to  adjust  the  inclination  of  the  movable  table,  the  pivots  q  being  points 
of  suspension. 

The  stuff  to  be  washed  is  placed  in  the  chest  a,  into  which  a  current  of  water  runs. 
The  ore,  floated  onwards  by  the  water, 

is  carried  through  a  sieve  on  a  small  527 

sloping  table  x,  under  which  is  con- 
cealed the  higher  end  of  the  movable 
table  (/,  b,  c,  u  ;  and  it  thence  falls  on 
this  table,  diffusing  itself  uniformly 
over  its  surface.  The  particles  de- 
posited on  this  table  form  an  oblong 
tahis  (slope)  upon  it ;  the  successive 
percussions  that  it  receives,  determine 
the  weightier  matters,  and  conse- 
quently those  richest  in  metal,  to  ac- 
cumulate towards  its  upper  end  at  x. 
Now  the  workman,  by  means  of  t!ie 
lever  p,  raises  the  lower  end  d  a  little 
in  order  to  preserve  the  same  degree 
of  inclination  to  the  surface  on  whicli 
the  deposit  is  strewed.  According  as 
the  substances  are  swept  along  by  the 
water,  he  is  careful  to  remove  them 
from  the  middle  of  the  table  towards 
the  top,  by  means  of  a  wooden  rake. 
"With  this  intent,  he  walks  on  the  table  d  b  c  i/,  where  the  sandy  sediment  has  sufficient 
consistence  to  bear  him.  When  the  table  is  abundantly  charged  with  the  washed  ore,  the 
deposit  is  divided  into  three  bands  or  segments,  d  b,  b  c,  c  n.  Each  of  these  bands  is 
removed  separately  and  thrown  into  the  particular  heap  assigned  to  it.  Every  one  of  the 
heaps  thus  formed  becomes  afterwards  the  object  of  a  separate  manipulation  on  a  percus- 
sion table,  but  always  according  to  the  same  procedure.  It  Js  sufBcient  in  general  to  pass 
twice  over  this  table  the  matters  contained  in  the  heap,  proceeding  from  the  superior  band 
c  u,  in  order  to  obtain  a  pure  schUcli ;  but  the  heap  proceeding  from  the  intermediate  belt 
b  c,  requires  always  a  greater  number  of  manipulations,  and  the  lower  band  d  b  still  more. 
These  successive  manipulations  are  so  associated  that  eventually  each  heap  furnishes  pure 
acldich,  which  is  obtained  from  the  superior  band  c  u.  As  to  the  lightest  particles  which  the 
water  sweeps  away  beyond  the  lower  end  of  the  percussion  table,  they  fall  into  launders, 
whence  they  are  removed  to  undergo  a  new  manipulation. 

Fig.  523  is  a  profile  of  a  plan  which  has  been  advantageously  substituted  in  the  Harz,  for 
that  part  of  the  preceding  apparatus  which  causes  the  jclt  of  the  piece  o  u  against  the 
table  db  c  11.  By  means  of  this  plan  it  is  easy  to  vary, 
according  to  the  circumstances  of  a  manipulation  al- 
ways  delicate,  the  force  of  percussion  which  a  bar  x  y 
ought  to  communicate  by  its  extremity  y.  With  this 
view  a  slender  piece  of  wood  «  is  made  to  slide  in  an 
upright  piece,  v  x,  adjusted  upon  an  axis  at  v.  To  the 
piece  u  a  rod  of  iron  is  connected,  by  means  of  a  hinge 
z;  this  rod  is  capable  of  entering  more  or  less  into  a 
case  or  sheath  in  the  middle  of  the  piece  v  x,  and  of 
being  stopped  at  the  proper  point,  by  a  thumb-screw 
which  presses  against  this  piece.  If  it  be  wished  to 
increase  the  force  of  percussion,  we  must  lower  the  point  z;  if  to  diminish  it,  we  must 
raise  it.  In  the  first  case,  the  extremity  of  the  piece  u  advances  so  much  further  under  the 
cam  of  the  driving  shaft  t\  in  the  second,  it  goes  so  much  less  forwards;  thus  the  adjust- 
ment is  produced. 

The  water  for  washing  the  ores  is  sometimes  spread  in  slender  streamlets,  sometimes  in 
a  full  body,  so  as  to  let  two  cubic  feet  escape  per  minute.  The  number  of  shocks  commu- 
nicated per  minute,  varies  from  1.5  to  36  ;  and  the  table  may  be  pushed  out  of  its  settled 
position  at  one  time  three-quarters  of  an  inch,  at  another  nearly  8  inches.  The  coarse  ore- 
sand  requires  in  general  less  water,  and  less  slope  of  table,  than  the  fine  and  pasty  sand. 

The  following  remarks  on  the  Freiberg  shaking-iahlc  are  by  Mr.  Upfield  Green,  of  the 
Wildberg  Mines,  Prussia.  The  bed  of  the  tabic  is  about  fourteen  feet  long,  by  six  feet 
wide,  aiKl  is  formed  of  double  one-inch  boards,  fastened  to  a  stout  frame.     The  table  is 


876 


ORES,  DRESSING  OF. 


hung  by  four  chains ;  the  two  hindermost  are  generally  two  feet  long,  with  an  incliuutiou 
of  2  to  4  inches.  The  two  front  ones,  which  are  attached  to  a  roller  for  the  purpose  of 
altering  the  inclination  of  the  table,  are  five  feet  six  inches  long,  and  hang  perpendicularly 
when  the  table  is  at  rest. 

The  table  receives  its  action  from  cams  inserted  in  the  axle  of  a  water-wheel,  acting  on 
the  knee  of  a  bent  lever.  The  slimes,  after  being  thoroughly  stirred  up  by  a  tormentor,  are 
conveyed  by  a  launder  in  a  box,  where  they  are  still  further  diluted  with  clean  water,  and 
passing  through  a  sieve  with  apertures  corresponding  to  the  size  of  the  grain  to  be  dressed, 
flow  upon  an  inclined  plane  furnished  with  diffusing  buttons,  and  from  thence 'drip  on  to  the 
shaking-table. 

In  treating  rough  slimes,  the  two  hindermost  chains  are  set  at  an  inclination  of  5  to  6 
inches;  and  the  table,  with  an  inclination  of  4  to  6  inches  on  its  length,  m;ikes  S6  to  39  pul- 
sations of  5  to  6  inches  in  length  per  minute.  About  2^  cubic  feet  of  diluted  slimes,  twelve 
of  clean  to  one  of  slime  water,  enter  the  table  per  minute. 

Before  commencing  the  percussive  action,  the  table  is  covered  witli  a  thin  layer  of  rough 
slimes,  and  during  the  first  few  minutes  only  clean  water  is  admitted.  In  consequence  of 
the  quantity  of  water  and  violent  motion  employed,  the  smaller  and  lighter  particles  of  ore 
are  likely  to  drift  down  the  table,  and  a  rake  is  therefore  employed  at  intervals  to  reconvcy 
such  particles  towards  the  head  of  the  table.  Care  must,  however,  be  taken  not  to  allow 
the  water  to  wear  furrows  in  the  deposit.  From  two  to  three  hours  are  usually  required  for 
the  roughest  .«and-slimes  to  deposit  four  to  five  inches  on  the  head  of  the  table.  The  crops 
are  twice  more  passed  over  the  shaking-table,  and  afterwards  dollied.  The  rnpidity  of  move- 
ment and  quantity  of  clean  water  increase  with  each  operation.  The  tails  of  the  first  opera- 
tion, which  are  considerably  poorer  than  the  original  stuff,  may  be  either  thrown  away,  or 
once  more  passed  over  the  table,  when  the  crop  will  be  fit  for  treatment  along  with  a  fresh 
quantity  of  original  slime.  The  treatment  of  fine  slimes  is  similar  to  that  of  the  rough, 
with  the  exception  that  the  inclination  of  the  table,  quantity  of  slime-water,  proportion  of 
clean  water,  and  length  of  stroke,  constantly  decrease  with  the  degree  of  fineness  of  the 
slime  ;  and  the  number  of  strokes  increase  in  proportion.  In  fact,  for  the  finest  slimes,  the 
table  has  no  greater  inclination  than  one  inch  on  its  whole  length,  while  the  stroke,  of  which 
35  to  45  per  minute  are  made,  is  no  longer  than  J  to  ^  an  inch.  The  time  required  for 
dressing  varies  with  the  nature  of  the  slime  operated  on ;  five  tons  of  rough  slimes  occupy 
sixty-eight  hours,  whilst  the  same  quantity  of  very  fine  slimes  requires  no  less  than  four 
times  that  period. 

The  Stosshcerd. — To  the  kindne.'^s  of  Mr.  Charles  Remfry,  of  Stolberg,  I  am  indebted 
for  the  elevation  of  a  stossheerd  erected  at  the  Breinigerberg  Mines,  under  his  management. 
It  has  the  merit  of  being  extremely  light,  requiring  little  power,  and  of  performing  its  work 
in  a  highly  satisfactory  manner.     Fig.  529,  a,  table  swung  by  chains,  b  b',  its  width  being 


3  feet  and  length  12  feet.  A  greater  or  less  inclination  is  given  to  the  tal/ic  by  rai.-ing  or 
lowering  the  screws  c  c'.  At  the  upper  end  of  the  table  is  a  buffer,  p,  which  acts  against  a 
counter-buffer,  e.  A  sliding  bar,  f,  is  also  fitted  between  the  table  and  percussion  lever  g. 
This  lever  is  struck  by  cams  fitted  on  the  axis  n,  driven  by  the  runner  J.  The  slimes 
to  be  treated  flow  into  the  cistern  k,  30  inches  long,  13  inches  wide,  and  IS  inches  deep. 
Into  this  box  a  tormentor  is  introduced  for  the  purpose  of  breaking  up  the  slimes.  The 
bottom  is  fitted  with  a  launder,  i,,  7  inches  long,  and  5  inches  wide.  From  this  launder  pro- 
ceeds a  head-board,  m,  expanded  to  the  width  of  the  table,  and  fitted  with  buttons,  for  the 
purpose  of  dispersing  the  slimes  eciually  on  the  head  of  the  table. 

At  the  Breinigerberg  Mines  the  slimes  are  very  fine  and  tough,  and  not  rich  in  metal. 
With  the  round  huddle  unimportant  results  were  obtained  ;  but  the  stossheerd  concentrated 


ORES,  DRESSING  OF. 


877 


them  satisfactorily.  About  five  tons  of  rough  slime  are  enriched  per  day  on  four  tables, 
whilst  from  nine  "to  ten  tons  of  the  enriched  slime  are  despatched  in  a  similar  period. 

The  four  tables  are  managed  by  two  boys,  at  a  cost  of  Is.  2d.  per  day.  The  cost  of 
these  machines  complete,  including  water-wheel,  9  feet  diameter,  and  3  feet  in  breast,  was 
£114. 

Sleeping  Tables. — Figs.  530,  531,  represent  a  complete  system  of  sleeping  tables,  tables 
doniantes,  such  as  are  mounted  at  Idria.     Fig.  530  is  the  plan,  and  Jig.  531  a  vertical  sec- 


tion. The  ores,  reduced  to  a  sand  by  stamps,  pass  into  a  series  of  conduits,  a  a,b  b,  c  c, 
which  form  three  successive  floors  below  the  level  of  the  floors  of  the  works.  The  sand 
taken  out  of  these  conduits  is  thrown  into  the  cells  q,  whence  they  are  transferred  into  the 
trough  f ,  and  water  is  run  upon  them  by  turning  two  stop-cocks  for  each  trough.  The  sand 
thus  diffused  upon  each  table,  runs  off  with  the  water  by  a  groove  /,  comes  upon  a  sieve  A, 
and  spreads  itself  upon  the  board  9,  and  thence  falls  into  the  slanting  chest  or  sleeping  table 
i  k.  The  under  surface  k  of  this  chest  is  pierced  with  holes,  which  may  be  stopped  at 
pleasure  with  wooden  plugs.  There  is  a  conduit  m  at  the  lower  end  of  each  table  to  catch 
the  light  particles  carried  off  by  the  water  out  of  the  chest  i  k,  through  the  holes  properly 
opened,  while  the  denser  parts  are  deposited  upon  the  bottom  of  the  chest.  A  general  con- 
duit 71  passes  across  at  the  foot  of  all  the  chests,  i  k,  and  receives  the  refuse  of  the  washing 
operation.^. 

In  certain  mines  of  the  Harz,  tables  called  il  balai,  or  sweeping  tables,  are  employed. 
The  whole  of  the  process  consists  in  letting  flow,  over  the  sloping  table,  in  successive  cur- 
rents, water  charged  with  the  ore,  which  is  deposited  at  a  less  or  greater  distance,  as  also 
pure  v,-ater  for  the  purpose  of  washing  the  deposited  ore,  afterwards  carried  off  by  means 
of  this  operation. 

At  the  upper  end  of  these  sweeping  tables,  the  matters  for  washing  are  agitated  in  a 
chest  by  a  small  wheel  with  vanes,  or  flap-boards.  The  conduit  of  the  muddy  waters  opens 
above  a  little  table  or  shelf;  the  conduit  of  pure  water,  which  adjoins  the  preceding,  opens 
below  it.  At  the  lower  part  of  each  of  these  tables  there  is  a  transverse  slit,  covered  by  a 
small  door  with  hinges,  opening  outwardly,  by  falling  back  towards  the  foot  of  the  table. 
The  water  spreading  over  the  table,  may  at  pleasure  be  let  into  this  slit,  by  raising  a  bit  of 
leather  which  is  nailed  to  the  table,  so  as  to  cover  the  small  door  when  it  is  in  the  shut 
position  ;  but  when  this  is  opened,  the  piece  of  leather  then  hangs  down  into  it.  Otherwise 
the  water  may  be  allowed  to  pass  freely  above  the  leather  when  the  door  is  shut.  The  same 
thing  may  be  done  with  a  similar  opening  placed  above  the  conduit.  By  means  of  these 
two  slits,  two  distinct  qualities  of  schlich  may  be  obtained,  which  are  deposited  into  two 
distinct  conduits  or  canals.  The  refuse  of  the  operation  is  turned  into  another  conduit,  and 
afterwards  into  ulterior  reservoirs,  whence  it  is  lifted  out  to  undergo  a  new  washing. 

Bruntori's  Jfachine. — This  apparatus  appears  to  be  well  adapted  for  the  utilization  of  the 
or»  contained  in  very  fine  slimes.     At  Devon  Great  Consols  it  is  extensively  (>niployed,  not 


878 


ORES,  DRESSING  OF. 


533 


only  to  concentrate  the  viscid  kind  of  slime  sometimes  found  at  the  periphery  of  the  round 
huddle,  but  also  to  dress  the  tops  and  middles  resulting  from  the  dollying  operation. 

The  small  water-wheel,  shown  in  fg.  532,  is  sufficient  to  drive  six  of  these  machines, 
viz.,  three  on  each  side.  Before  the  stuff  is  permitted  to  enter  upon  the  rotating  cloth,  it 
is  disintegrated  by  tormentors,  and  passed  through  a  sizing  trommel ;  it  then  flows  over  the 
head  or  dispersing  board  l,  on  to  the  cloth.  This  cloth  rotates  towards  the  stream  on  two 
axles,  H  and  m,  and  is  supported  by  a  third  roller  n.  It  is  also  stiffened  in  its  width  by  nu- 
merous laths  of  wood.  Clean  water  is  introduced  behind  the  entrance  of  the  slime,  in 
order  to  give  it  the  proper  consistency.  Different  degrees  of  inclination  are  given  to  the 
cloth  by  raising  or  lowering  the  roller  m,  by  means  of  the  screw  k.  The  heavier  particles 
lodged  on  the  cloth  are  caught  in  the  wagon  r,  whilst  the  lighter  matter  is  floated  over  the 
roller  m.  The  following  particulars  are  furnished  by  Captain  Isaac  Richards,  of  Devon 
Great  Consols: — 

One  revolution  of  the  cloth  is  made  in  4|-  minutes  ;  its  length  is  about  29^  feet,  so  that 
it  travels  say  G4-  feet  per  minute.     Its  width  is  four  feet  two  inches. 

Before  the  slime  comes  upon  the  cloth  it  is  reduced  to  a  size  of  '/eo  of  an  inch,  and 
yields  an  average  of  li  of  copper  ;  but  by  means  of  this  machine  the  stuff  is  concentrated 
so  as  to  afford  5  per  cent.  In  ten  hours  it  will  clean  1|  tons,  at  a  cost  of  Is.  per  ton.  The 
speed  of  the  cloth  must,  however,  be  varied  with  the  condition  of  the  stuff;  if  it  be  very 
poor,  the  cloth  must  travel  verj  much  slower,  since  the  enrichment  requires  a  longer  period 
of  time. 

At  the  end  of  the  machine,  and  worked  by  the  same  water-wheel,  is  a  dolly  tub ;  but 
the  mode  of  working  this  apparatus  is  fully  stated  on  the  next  page. 

Bradford's  Slime  Apparafus,  fg.  633,  has  been  extensively  employed  at  the  Bristol 
Mines,  situated  in  Connecticut,  United  States. 

Its  action  is  intended  to  imitate  that  of  the 
vanning  shovel.  The  slime  enters  by  the  launder 
A,  about  5  inches  wide,  and  descends  on  the  in- 
clined head  a',  which  expands  from  the  width  of 
the  launder  to  within  a  few  inches  of  the  width 
of  the  table  frame  b.  The  slime  box  a"  is  per- 
forated at  D  with  numeroiLS  holes,  each  of  which 
is  fitted  with  small  regulating  pins. 

The  table  b  b  is  2  feet  2  inches  wide,  and  2 
feet  10  inches  long,  with  a  bottom  formed  of  cop- 
per gauze.  It  is  suspended  by  the  vertical  rods  ^ 
K  K,  and  varying  degrees  of  inclination  are  given 
to  the  table  by  altering  the  levers  h  ii.  For  the 
purpose  of  quickening  or  decreasing  the  action 
of  the  table,  two  cones  are  employed,  l  l',  upon 
which  the  driving  band  is  shifted  as  may  be  neces- 
sary. A  band  f^i-om  a  runner,  fitted  on  the  axis 
of  the  cone  i.,  communicates  motion  to  a  pulley- 
wheel,  M,  upon  the  shaft  of  which  are  cranks 
attached  to  connecting  rods  G,  giving  motion  to 
the  table. 

When  the  machine  is  in  operation,  the  ore 
flows  over  at  f,  into  the  launder  beneath  it, 
whilst  the  waste  is  carried  over  the  opposite  end 
into  the  trough  e. 

Prof.  B.  Silliman,  Jr.,  and  Mr.  J.  D.  "Whitney, 
give  the  following  particulars  of  results  realized 
by  this  machine  : — The  total  weight  of  ore  stuff 
pressed  during  122  days  was  11,948,900  pounds 
of  rock  stamped  and  crushed,  or  5,080  tons 
miners'  weight. 

The  total  ore  sold  from  this  quantity  of  stuff 
was  128  gross  tons,  (2,352  lbs.)  or  2''Vino  per  cent, 
of  the  stuff  worked  over.  By  the  Captain's  vans 
tlie  average  richness  of  the  stamp  work  (forming 
much  the  larger  part  of  what  goes  to  the  separa- 
tors) for  22  weeks  was  2*32  per  cent.  The  humid 
assay  of  the  average  work  from  the  stamps  for 
five  weeks  in  July  and  August,  gave  for  the  rich- 
ness of  the  stuff  dressed  on  the  separators  3'28 
per  cent,  of  ore,  or  -984  per  cent,  of  metallic  copper.  There  is,  therefore,  an  apparent  loss 
in  the  tailings  of  "/loo  per  cent,  of  30  per  cent,  ore,  or  '^Vioo  of  copper.     The  amount  of 


ORES,  DRESSING  OF. 


879 


ore,  however,  lost  in  the  tailings  does  not  exceed  */io  to  7io  per  cent.,  or  about  "/loo  per 
cent,  of  copper.  The  actual  products  of  working,  therefore,  as  may  be  seen,  exceed  for  the 
machines  the  average  richness  of  the  Captain's  vans. 

Of  the  total  ore  produced  in  this  time,  181,126  pounds  came  from  the  separators,  and 
160,858  pounds  from  the  jiggers.  The  whole  amount  of  stuff,  therefore,  required  to  pro- 
duce this  amount  of  ore,  estimated  from  the  above  ratio  (1.15  :  1)  is  768,680  pounds. 
This  may  be  taken  approximately  as  the  actual  quantity  which  passed  over  the  separators, 
and  if  calculated  on  the  Captain's  vans,  it  should  have  produced  177,061  pounds  of  ore, 
while  in  fact  it  did  produce  181,126  pounds,  or  a  variation  in  excess  for  the  machines  of 
only  3,210  pounds.  Each  of  the  separators,  therefore,  dresses  about  1^  tons  of  rock  daily, 
of  stuff  yielding  an  average  of  2'5  per  cent,  of  30  per  cent.  ore. 

Dolly  Tub  or  Packing -Keeve. — This  apparatus  is  employed  for  the  purpose  of  excluding 
fine  refuse  from  slime  ore,  which  has  been  rendered  nearly  pure  by  previous  mechanical 
treatment.  In  using  it  the  workmen  proceed  thus : — The  keeve,^5r.  534,  is  filled  to  a  cer- 
tain height  with  water,  and  the  dolly  a  introduced.  A  couple  of  men  then  take  hold  of  the 
handle  b,  and  turning  it  rapidly  cause  the  water  to  assume  a  circular  motion.  The  tossing 
is  then  commenced  by  shovelling  in  the  slime  until  the  water  is  rendered  somewhat  thick. 
After  continuing  the  stirring  for  a  short  period,  the  hasps  e  e  are  loosened,  and  the  bar  d 
with  the  dolly  suddenly  withdrawn.  The  tub  is  then  packed  by  striking  its  outside  with 
heavy  wooden  mallets.  When  this  operation  is  terminated,  the  water  is  poured  off  through 
plug-holes  in  the  side  of  the  tub. 

The  object  of  the  rotary  motion  created  by  the 
dolly  is  to  scour  off  clayey  or  other  matter  ad- 
hering to  the  ore,  whilst  the  packing  hastens  the 
subsidence  of  the  denser  portions.  In  one  opera- 
tion of  this  kind  four  distinct  strata  may  be  pro- 
cured, as  indicated  by  the  lines  a  b,  c  d,  cf,  g  /;, 
c  Z.-,  iuyfr/.  535. 

The  upper  portion,  viz.  from  a  to  b,  will  prob- 
ably have  to  be  set  aside  for  further  washing, 
whilst  the  schlich  c  should  be  fit  for  market. 
The  conical  nucleus  in  the  centre  of  the  tub 
generally  consists  of  coarse  sand,  and  is  usually 
further  enriched  on  a  copper  bottom  sieve,  or 
else  submitted  to  the  action  of  a  tye,  or  other 
suitable  apparatus. 

ILtcfiine  Dollg  Tub. — This  keeve  is  packed 
by  machinery  represented  in  the  accompanying 


584 


880 


ORES,  DRESSING  OF. 


woodcut,  {fg-  53fi,)  in  which  a  is  a  small  water-wheel  working  a  vertical  shaft  b,  and  drivin" 
another  o.  At  the  bottom  of  this  is  fixed  a  notched  wheel  d,  which  presses  outwardly  the 
hammers  K  E ;  these  are  mounted  upon  iron  bars  F  f',  and  violently  driven  upon  the  side  of 
the  keeve  by  means  of  springs  g  g'. 

The  degree  to  which  ore  can  be  concentrated  by  dollying  must  evidently  depend  upon 
several  conditions: — 1st.  The  initial  percentage  of  the  ore.  2d.  The  condition  to  which  it 
is  reduced.  3d.  The  matrix  with  which  it  is  associated.  4th.  The  proportion  of  water  em- 
ployed. And  lastly,  if  the  rotation  and  packing  have  been  judiciously  performed.  An 
experiment  upon  some  sandschlich  lead  ore,  much  intermixed  with  fine  carbonate  of  iron, 
gave  the  following  results: — 

Introduced  into  dolly  tub,  17  cwt.,  assayed,  487o 

Time  required  to  introduce  stuff        .... 

Dolly  rotated  ....... 

Dolly  withdrawn — 

Tub  packed 

Running  off  water 

Skimming  and  cleaning  out  tub         .... 


Top  skimmings    - 
Second    " 
Clean  ore,  middles 
"  bottom 


4  cwt,  assayed 


Total 


6  minutes 

5 

11 

5 

u 

6 

11 

20 

tt 

42 

- 

20Vc 

- 

45 

. 

65 

- 

6VJ 

Fine  schlich 


Total      -         11 

It  may  be  remarked,  that  none  of  the  various  processes  of  dressing  is  more  satisfactory 
than  that  of  dollying,  since,  if  carefully  conducted,  little  or  no  loss  of  the  total  quantity  of 
ore  can  occur. 

Jordan's  System  of  coxTiNUors  Dressing. 

"We  have  now  to  notice  a  method  of  separating  mineral  sands  of  varying  specific  gravity, 
which  was  first  used  by  Mr.  T.  B.  Jordan  at  the  Colonial  Gold  Works,  in  separating  gold 
from  quartz  and  other  gangues  with  which  it  was  associated.  The  plan  was  successfully 
practised  for  its  original  object  during  the  years  1853  and  1854,  and  lias  since  been  elabo- 
rated for  general  application  to  dressing  minerals. 

The  principle  on  which  the  system  is  founded,  is  the  fact  that  bodies  having  the  same 
bulk  and  various  gravities,  will  fall  through  a  column  of  water  in  the  order  of  their  densi- 
ties, and  hence  that  water  moving  upwards,  at  a  rate  greater  than  that  at  which  any  given 
body  would  descend  through  still  water,  will  not  allow  such  a  body  to  descend  through  it, 
but  will  carry  it  up,  and  deliver  it  over  the  top  of  the  containing  vessel ;  therefore,  granting 
that  it  is  possible  to  reduce  metalliferous  ores  to  grains  of  uniform  bulk,  and  taking  the 
most  simple  case  for  our  illustration,  such  as  galena  and  carbonate  of  lime,  or  quartz,  it 
becomes  at  once  obvious  that  an  upward  stream  of  water  may  be  so  regulated  as  to  throw 
over  all  the  lime  or  quartz,  and  allow  all  the  galena  to  pass  through  it ;  but  as  we  seldom 
find  the  associated  material  so  simple,  and  as  there  is  considerable  difficulty  in  reducing 
minerals  to  grains  of  absolute  identity  of  bulk,  we  must  be  content  to  complicate  our  ma- 
chinery a  little,  and  to  put  up  with  a  somewhat  less  perfect  or  more  laljorious  result  than 
this  argument  seems  to  promise ;  nevertheless  the  author  of  this  system  contends,  that  the 
introduction  of  tliis  clement  of  was/ting  by  the  np  current,  greatly  facilitates  the  arrange- 
ment of  dressing  machinei-y  of  continuous  action  ;  and,  further,  that  if  perfectly  continuous 
action  can  be  secured,  so  that  each  machine  shall  deliver  its  products  to  the  next  in  succes- 
sion which  is  to  be  employed  on  them,  a  very  great  improvement  will  have  been  effected,  and 
a  great  saving  made  on  the  present  cost  of  dressing ;  for  it  would  not  be  difficult  to  show 
that  nine-tenths  of  the  labor  consist  of  putting  down,  picking  up,  and  transferring  the 
matefial  to  the  various  processes  through  which  it  passes. 

Our  figure  (537)  must  be  taken  as  a  diagram  illustrative  of  Mr.  Jordan's  views.  In  actual 
practice,  the  construction  is  varied  to  meet  the  peculiarities  of  each  case,  while  the  general 
principle  here  illustrated  is  strictly  adhered  to.  a  is  a  tram  bringing  the  rough  material  to 
the  crushing  rollers  d  ;  c  c  is  a  sort  of  raff  wheel  so  arranged  as  not  only  to  serve  the  usual 
purpose  of  returning  the  stuff  not  sufficiently  crushed  to  the  rollers,  but  also  to  separate  that 
which  is  crushed  into  four  or  more  sizes  by  the  concentric  rings  of  wire-work  which  divide 
the  wheel  into  the  compartments  6,  8,  10,  12.  These  numbers  may  be  taken  to  denote  tlie 
mesh  in  holes  per  lineal  inch,  and  if  so,  all  the  materials  from  the  crushing  rolls  being  con- 
veyed into  the  centre  opening  of  the  wheel  will  be  sharply  rolled  over  a  six-hole  sieve  of 


OEES,  DRESSING  OF. 


881 


great  area ;  that  part  of  it  which  is  fine  enough  will  pass  through  the  mesh,  that  which  is  not 
will  be  carried  up  by  the  partition  or  bucket  which  returns  it  to  the  mill  for  further  grinding. 
In  the  stuff  whicla  has  passed  the  ti-hole  sieve,  and  reached  the  compartment  marked  6, 


there  will  be  a  large  proportion  which  will  pass  the  next  or  8-hole  sieve,  and  again  from  the 
8  to  the  10  and  12,  so  that  this  wheel  separates  the  ground  stuff  into  four  lots  of  approxi- 
mately uniform  grain.  To  secure  the  greatest  effect  from  this  separator,  the  stuff  must  be 
either  perfectly  dry,  or  ground  with  a  good  stream  of  water  passing  between  the  rolls  and 
through  the  wheel.  Each  compartment  of  the  wheel  is  furnished  with  one  stop-bucket  and 
spout  which,  when  it  arrives  at  the  top,  delivers  the  contents  of  the  compartment  collected 
during  the  revolution  into  separate  launders  which  carry  it  to  as  many  different  tubes,  one 
of  which  is  shown  at  d.  These  tubes  are  supplied  with  water  from  a  main  p,  which  is  in 
connection  with  a  reservoir  some  12  or  14  feet  above  the  level  of  the  dressing  floor;  a  few 
inches  above  the  true  bottom  of  the  vessel  n,  there  is  a  false  bottom  or  diaphragm  of  wire- 
gauze,  through  which  the  water  rises.  Under  the  conditions  described,  the  superintendent 
will  have  the  power  of  regulating  exactly  the  quantity  of  water  which  shall  rise  through 
each  tube  in  a  given  time,  and  therefore  the  rate  of  the  upward  flow  of  the  water ;  or,  in 
other  words,  he  will  be  able  so  to  adjust  each  stream  as  to  throw  over  the  waste,  and  allow 
the  valuable  part  of  each  sand  to  fall  on  the  wire  bottom  of  its  tube.  It  is  of  course  admit- 
ted that  the  sizing  effected  in  the  wheel  c,  although  better  than  by  the  usual  methods,  is 
still  but  an  approximation  to  perfect  sizing ;  and  even  if  in  the  wheel  it  were  perfect,  still 
the  rush  through  the  launders  would  inevitably  produce  some  dust  ore  if  dry,  or  slime  ore 
if  wet,  so  that  it  would  not  do  to  throw  away  ail  that  is  washed  over  the  top  of  the  tubes;  it 
therefore  passes  forward  to  the  hutch  e,  where  it  falls  on  a  fine  gauze  bottom  sieve,  parted 
longitudinally  into  as  many  divisions  as  there  are  tubes  or  sizes  of  sand  to  be  worked ;  the 
bottom  of  each  of  these  divisions  is  composed  of  a  wire  gauze,  somewhat  finer  than  that  of 
the  compartment  of  the  parting  wheel  from  which  the  sand  came,  and  therefore  none  of  the 
waste  can  find  its  way  into  the  hutch  ;  the  action  of  this  sieve  is  widely  different  from  that 
of  a  jigging  machine,  inasmuch  as  the  back  and  fore  part  of  it  have  a  different  kind  of  mo- 
tion, and  it  is  a  machine  of  continuous  action,  not  requiring  the  constant  attention  of  skilled 
labor.  The  crank  G,  by  its  constant  rotation,  dips  the  back  of  the  sieve  a  few  inches  under 
water,  and  at  the  same  time  draws  it  back  through  the  water  at  every  revolution,  and  on 
rising  and  passing  over  the  upper  half  of  its  revolution,  it  frees  the  sieve  forward,  while  all 
its  contents  are  above  the  surface  of  the  water  in  the  hutch.  The  front  of  the  sieve  is  sus- 
.pended  by  a  pendulous  rod  from  the  point  n,  so  that  it  has  very  little  elevation  and  depres- 
sion, while  it  has  the  same  lateral  motion  as  the  back,  and  this  enables  the  sim|)le  hanging 
scraper,  which  can  move  freely  outwards  but  cannot  pass  inwards  beyond  the  perpendicular, 
to  throw  over  a  portion  of  the  waste  at  every  stroke,  this  I)eing  much  assisted  by  the  stream 
constantly  flowing  over  it.  There  are  cleats  placed  acro.ss  the  bottom  of  these  sieves  both 
above  and  below,  the  tendency  of  which  in  giving  direction  to  the  waste,  and  stopping  the 
rich  slimes,  will  be  readily  understood  on  reference  to  the  figure.  The  dolly  tub  K  is 
Vol.  III.— 56 


882 


ORES,  DRESSING  OF 


intended  to  meet  the  case  of  secondary  products,  such  as  "Jack,"  or  other  ore  of  zinc,  fre- 
quently associated  with  lead.  Tiie  peculiarities  of  its  construction  are  such  as  are  requisite 
to  avoid  the  necessity  for  stopping  and  takiiifi  the  machine  apart  in  order  to  dig  out  its 
contents ;  it  is  accomplished  partly  by  the  direction  given  to  the  revolving  arms  which  tend 
to  lift  the  stuff,  but  prmcipally  by  an  up  current  of  water  of  sufficient  rate  to  throw  over  the 
lit^htest  of  the  two  materials  now  associated  ;  as  in  the  former  case  the  original  sizing  is  not 
abandoned,  but  a  separate  dolly  tub  is  used  for  each  size,  so  that  the  up  current  may  still  be 
adjusted  to  its  work  with  the  greatest  precision  ;  the  step  or  bearing  in  the  bottom  of  the 
tub  is  protected  from  the  sand  by  a  sheet-iron  cone  attached  to  the  shaft,  into  which  the 
clean  water  from  the  main  is  supplied,  so  that  the  stream  of  water  constantly  running  from 
under  the  edges  of  this  cone,  keeps  the  step  at  all  times  perfectly  clean  and  free  from  sand  ; 
p  is  the  main  for  supplying  to  the  tub,  and  there  is  a  tap  on  the  communicating  pipe  which 
regulates  its  forces  m  is  the  waste  wagon,  having  a  riddled  bottom  for  drawing  off  the  wa- 
ter; 0  is  the  "Jack"  wagon  into  which  the  clean  stuff  from  the  tub  is  occasionally  dis- 
charged by  the  sluice  valve ;  and  n  is  the  lead  wagon  for  carrying  awa'y  the  clean  ore  from 
the  tubes ;  this  wagon,  like  the  others,  is  furnished  with  a  riddled  bottom  covered  with  some 
material  which  is  too  fine  in  the  mesh  to  allow  any  of  the  ore  to  pass ;  the  oie  is  drawn  off 
from  the  washing  tubs  from  time  to  time  in  small  quantities ;  each  wagon  remains  under  its 
own  tube  until  it  has  received  a  full  load,  and  is  then  wheeled  off  to  the  ore  house;  by  this 
system,  the  inventor  says,  nothing  is  left  to  clean  up  but  the  hutch  f,  and  its  sieve,  which 
latter  may  require  looking  to  two  or  three  times  a  day,  and  the  bottom  of  hutch  about  once 
in  three  days. 

Vcauiing  is  a  method  commonly  practised  by  the  dressers  of  Cornwall  and  Devonshire, 
by  which  they  ascertain  approximately  the  richness  and  properties  of  the  ore  to  be  treated. 
If  the  object  be  to  determine  the  value  of  a  pile  of  stuff,  it  is  carefully  divided,  then  sampled, 
and  a  portion,  say  a  couple  of  ounces,  given  to  the  vanner.  If  the  stuff  thus  given  should 
be  rough,  it  is  reduced  to  the  tenure  of  fine  sand,  and  in  this  state  put  upon  the  vanning 
shovel.  The  operator  now  resorts  to  a  cistern  or  stream  of  water,  and  bj  frequently  dip- 
ping the  shovel  into  it,  and  imparting  to  the  shovel  when  withdrawn  a  kind  of  irregular  cir- 
cular motion,  he  succeeds  in  getting  rid  of  a  greater  or  less  portion  of  the  waste :  that  which 
remains  on  the  shovel  is  then  considered  equal  to  dressed  work  and  assayed.  So  accurately 
is  this  operation  performed  bv  many  of  the  tinners,  that  parcels  containuig  only  fifteen 
pounds  of  tin  ore  per  ton  of  stuff,  are  sold  by  it  to  the  mutual  satisfaction  of  both  buyer 
and  seller. 

The  vanning  process  is  also  well  adapted  for  determining  the  properties  of  an  ore.  If, 
by  this  method,  vein  stuff  should  withstand  concentration,  no  machinery  is  likely  to  dress  it. 
If  also  the  loss  of  ore  is  found  great,  then  the  apparatus  to  be  employed  for  effecting  the 
enrichment  will  have  to  be  carefully  considered  and  constructed. 

Fig.  538.     The  vanning  shovel  a  is  14  inches  long,  and  13  inches  wide  at  the  top,  the 


edge  of  which  is  slightly  turned  up.     The  shovel  is  also  formed  with  a  hollow  or  depression. 
The  handle  is  about  4  feet  long.     The  vanning  cistern  is  shown  at  b. 

Hushing. — It  often  occuis,  that  the  water  employed  on  the  dressing  floors  makes  its 
escape  below  the  refuse  or  waste  heaps.  This  may  be  used  for  the  purpose  of  hushing, 
which  operation  is  performed  in  the  following  manner: — The  husher  diverts  the  escape 
water  into  a  rivulet  and  introduces  a  given  quantity  of  waste.  He  then  builds  a  dam  or 
reservoir,  with  a  door  or  traj)  valve  at  the  high  end,  in  order  to  collect  the  necessary  water 
for  hushing,  and  puts  aside  all  the  large  stones  lying  in  the  middle  of  the  hush  gutter  in 
order  to  form  them  into  a  wall.  After  this,  he  starts  his  hush  by  lifting  the  door  of  the  dam, 
which  slides  in  a  wooden  frame  adapted  for  that  purpose. 


ORES,  DRESSING  OE. 


883 


This  allows  the  water  to  rush  out,  aud  displaces  the  waste  to  a  certain  depth,  at  the  same 
time  driving  it  forward. 

If  the  husli  has  bared  or  uncovered  a  further  quantity  of  large  stones  in  the  middle  of 
the  gutter,  they  are  again  removed  to  one  side,  since  they  would  retard  the  force  and  action 
of  the  water.  When  these  impediments  are  removed,  the  water  is  repeatedly  discharged 
from  the  reservoir  until  the  waste  is  hushed  off  the  ore,  which  Ls  found  lying  in  holes,  and 
around  earth  and  fiist  stones,  in  the  bed  of  the  rivulet.  A  clay  bottom  is  found  to  be  most 
favorable  for  hushing,  and  the  velocity  and  power  of  the  stream  should  be  proportioned  to 
the  size  and  density  of  the  waste  to  be  treated. 

Forwarding  and  Lifting  Apparatus. 

Besides  the  machinery  required  for  the  enrichment  of  ores,  it  is  a  matter  of  great  im- 
portance to  introduce  such  auxiliary  arrangements  as  shall  not  only  facilitate  actual  dressing, 
but  also  be  in  themselves  somewhat  inexpensive.  In  this  division,  as  in  every  other,  the 
means  should  be  strictly  adapted  to  the  end,  and  ought  not  to  bear  a  cost  disproportionate 
either  to  the  circumstances  or  prospective  advantages  of  an  undertaking. 

The  shovel,/^.  539,  usually  employed  in  British  mines,  is  of  triangular  shape,  and  made 
of  good  hammered  iron  pointed  with  steel.  The  dimensions  vary,  but  one  of  an  average 
size  is  about  II  inches  wide  at  the  top,  and  13  inches  from  the  point  to  the  shank,  weight  4 
pounds,  and  costs  one  shilling;  to  which  must  be  added,  five  pence  for  the  hilt,  or  handle. 
The  hilt  should  be  of  ash,  free  from  knots  and  slightly  curved. 


539 


510 


Picking  Boxen,  fig.  540,  are  employed  for  the  purpose  of  collecting  the  prill  and  dradge 
ore  from  the  stuff  with  which  it  may  be  mechanically  intermixed.  These  boxes,  or  trays, 
are  handled  by  children.  They  are  made  of  deal,  1  inch  thick,  of  the  following  dimensions : 
Length,  16  inches;  depth,  7  inches;  width  at  bottom,  7  inches;  width  at  top,  10  inches; 
and  cost  about  Is.  Zd.  each.  A  ledge  of  wood  to  serve  as  a  handle  is  sometimes  nailed  to 
the  ends  of  the  box. 

Wheelbarrow. — The  sides,  ends,  and  bottom  are  composed  of  deal  1^  inches  thick.  The 
ends  are  mortised  to  the  sides,  whilst  the  bottom  is  generally  fostened  by  means  of  nails, 
and  bound  with  slips  of  hoop  iron  at  the  angles.  Hoop  iron  is  also  employed  to  protect  the 
upper  edges  of  the  barrow.  The  wheel  is  often  made  of  wrought  iron,  (f  round,)  and  14 
inches  diameter.  Its  axes  rotate  in  wrought-iron  ears.  The  extreme  length  of  the  sides 
of  a  well-proportioned  barrow  is  60  inches,  depth  at  centre  9  inches ;  the  ends  are  inclined, 
as  shown  in  fig.  541.  The  cost  of  a  barrow  with  wrought-iron  wheels  complete  will  vary  from 
6s.  I6d.  to  7s. 


541 


542 


513 


Hftndbarrow. — When  large  quantities  of  stuff  have  to  be  removed  from  place  to  place 
on  the  surface,  and  where  it  would  be  inconvenient  to  use  the  wheelbarrow,  a  barrow  having 
handles  at  both  ends  is  employed.  It  is  made  of  deal  plank  1;^  inches  thick  ;  the  length  of  the 
sides  is  5  feet  6  inches ;  depth  in  centre,  9  inches ;  width, 
18  inches  at  top  and  10  inches  at  bottom;  length,  24 
inches  at  top  and  18  inches  at  bottom-  cost  complete, 
about  4s.  &d. 

Railroads. — The  gauge  of  surface  roads  varies  from 
2* feet  4  to  2  feet  6  inches  within  the  rails.  Instead  of 
manufactured  rails,  common  flat  wrought-iron,  24  inches 
wide  and  ^  inch  thick,  is  oftentimes  employed.  An  ex- 
tremely serviceable  rail  is  formed  of  a  strip  of  timber  2 
inches  square,  upon  which  is  laid  wrought-iron,  l^-  inches 
wide  and  J  inch  thick,  fastened  by  means  of  nails  or  screws. 

Tram  \V(tgon  and  Turn  Tabic. — A  good  tram  wagon 
and  turn  table  are  sliown,  /fr/.  54:^.  The  wagon  is  built  of 
wrought-iron,  with  cast-iron  wheels.  The  latter  are  usually 
12  inches  diameter,  with  flanges  1  inch  deep  and  tires 
from  2  to  3  inches  wide.     The  turn  fable  is  of  cast-iron. 


8S4: 


ORES,  DRESSING  OF. 


It  does  not  rotate,  but  the  wagon  is  easily  directed  to  either  line  of  rail  by  means  of  the  cir- 
cular ring ;  the  elliptical  loops  in  advance  serving  to  guide  and  place  the  wheels  on  the  rails. 
Lifting  Apparatus. — It  sometimes  happens  that  the  surface  is  nearly  level,  and  affords 
very  little  natural  fall.  In  such  case  the  enrichment  of  ores  becomes  more  expensive  from 
the  necessity  of  shifting  some  of  the  various  products  by  manual  labor,  and  of  introducing 
lifting  appliances  in  order  to  procure  the  requisite  elevations  for  carrying  out  the  various 
elaborative  processes.  It  is,  moreover,  scarcely  practicable  from  the  conformation  of  the 
ground  to  form  useful  reservoirs  of  water  within  a  reasonable  distance  ;  neither  does  it  com- 
monly occur  in  such  cases  that  a  free  supply  can  be  obtained  for  washing. 

The  pumping  engine  is  therefore  required  to  furnish  the  requisite  quantity  of  water. 
This  is  generally  conveyed  over  the  floors  by  wood  launders, 
often  interfering  with  each  other  and  obstructing  the  direct 
circulation  of  carts,  railways,  &c.  Now  if  a  stand-pipe  or 
pressure  column  were  erected  at  the  engine,  and  a  main 
judiciously  laid  throughout  the  floors,  it  is  obvious  that  it  would 
not  only  remedy  this  evil,  but  also  afford  water  for  the  several 
washing  purposes,  as  well  as  motive  power  for  common,  dash, 
or  other  wheels,  together  with  turbines,  flap  jacks,  &c. 

When  an  inconsiderable  proportion  of  water  has  only  to 
be  raised  to  a  higher  level,  the  common  shoe  or  chain-pump 
will  be  found  to  render  effective  service ;  but  when  a  larger 
stream  is  requisite,  it  would  be  better  to  employ  the  rotary 
pump.  This  pump,  Jiff.  544,  has  been  brought  to  great  per- 
fection by  Messrs.  Gwj-nne  ;  a  is  the  suction-pipe,  and  b  the 
discharge,  the  dotted  lines  showing  the  discharge  B,  horizontal 
when  required. 

Pumps  of  the  following  dimensions  are  stated  to  raise  and  discharge  per  minute  for 
medium  lifts,  say  from  10  to  10  feet  high: — 

Diameter  of  Diameter  of  Gallons  of 

discbargc-pipe.  suction-pipe.  water  per  minute. 

1^  inches.  2  inches.  25 


E 


'70 

150 

300 

500 

1400 


Stuff  consisting  of  slimes  and  sand  may  be  readily  elevated  by  means  of  a  Jacob's  lad- 
der or  the  Archimedean  screw.  For  short  elevations  combined  water  and  raff  wheels  devis- 
ed by  Mr.  Charles  Remfry  of  Stolberg,  Prussia,  may  be  advantageously  employed. 

Fig.  645,  a,  water-wheel ;  b,  raff  or  inverted  wheel ;  c,  axis  of  both  raff  and  water- 


645 


^pl^^^^^^^^^^l , 


wheels,  carrying  a  tooth-driving  wheel;  n,  sizing  trommel;  e,  launder  for  inlet  of  stuff;  f, 
discharge  launder;  G,  shoot  .delivering  water  and  raff  to  launder  ii ;  e,  cistern  receiving 
slime  from  trommel. 

Slime  Pits. — In  the  several  operations  of  cleansing  ores  from  mud,  in  grinding,  and 
washing,  where  a  stream  of  water  is  used,  it  is  impossible  to  prevent  some  of  the  finely 
attenuated  portions  floating  in  the  water  from  being  carried  off  with  it.     Slime  pits  or 


OXIDES. 


685 


labyrinlhx,  called  huddle  holes  in  Derbyshire,  are  employed  to  collect  that  matter,  by  receiv- 
ing the  water  to  settle  at  a  little  distance  from  the  place  of  agitation, 

These  basins  or  reservoirs  are  of  various  dimensions,  and  from  24  to  40  inches  deep. 
Here  the  suspended  ore  is  deposited,  and  nothing  but  clear  water  is  allowed  to  escape. 

The  workmen  employed  in  the  mechanical  preparation  of  the  ores  are  paid,  in  Cumber- 
land, by  the  piece,  and  not  by  day's  wages.  A  certain  quantity  of  crude  ore  is  delivered 
to  them,  and  their  work  is  valued  by  the  bing,  a  measure  containing  14  cwt.  of  ore  ready 
for  smelting.  The  price  varies  according  to  the  richness  of  the  ore.  Certain  qualities  are 
washed  at  the  rate  of  2?.  GJ.,  or  3.s-.  the  bing ;  while  others  are  worth  at  least  lO.s.  The 
richness  of  the  ore  varies  from  2  to  20  bings  of  galena  per  sJdft  of  ore ;  the  shift  corre- 
sponding to  S  wagon  loads. 

It  is  not  essential  to  describe  the  dressing  routine  observable  in  any  particular  mine, 
since  it  is  scarcely  possible  to  observe  the  same  system  in  any  two  distinct  concerns.  In 
the  various  modes  of  treatment,  however,  it  may  be  remarked  that  the  two  leading  features 
will  always  be  reduction  to  a  proper  size  and  separation  of  the  ore  from  the  refuse. 
Until  the  vein  stuff  arrives  at  the  crusher  or  stamps,  the  labor  is  chiefly  one  of  picking  and 
selecting,  but  from  these  machines  usualh'  commence  a  long  series  of  divisions,  subdivisions, 
selections,  and  rejections.  To  follow  these  out  in  their  various  ramifications  would  not 
only  exceed  the  limits  of  this  paper,  but  would  perhaps  be  misunderstood  by  those  not 
intimatelv  acquainted  with  the  subject. — J.  D. 

OTTO,  OTTAR,  or  ATTAR  OF  ROSES.  Otto  of  roses  consists  of  two  volatile  oils  ;  one 
solid  and  the  other  liquid  at  ordinary  temperatures,  in  the  proportion  of  about  one  of  the 
former  to  two  of  the  latter.  To  separate  them,  the  otto  must  be  frozen  and  compressed 
between  folds  of  blotting  paper,  which  absorb  the  liquid,  and  leave  the  solid  oil.  They 
may  also  be  separated  by  alcohol,  (of  sp.  gr.  -8,)  which  dissolves  the  liquid  and  scarcely  any 
of  the  solid  oil.  The  solid  oil,  according  to  Saussure,  contains  only  carbon  and  hydrogen, 
and  these  in  equal  number  of  atoms,  and  is  therefore  isomeric  with  oil  of  turpentine ;  it 
occurs  in  cry.stalline  plates,  fusible  at  95^  F.  The  liquid  oil  has  not  been  carefully  ex- 
amined ;  it  is  uncertain  whether  it  contains  nitrogen,  or  only  carbon,  hydrogen,  and  oxygen. 

Otto  of  roses  is  sometimes  adulterated  with  some  essential  or  fixed  oils  and  spermaceti. 
The  purity  of  the  otto  is  determined  by  the  following  test :  put  a  drop  or  two  of  the  oil  to 
bo  tested  in  a  watch-glass,  and  then  add  as  many  drops  of  concentrated  sulphuric  acid  as  of 
the  oil ;  mix  with  a  glass  rod.  All  the  oils  are  rendered  more  or  less  dark-colored  by  this 
process,  while  the  otto  of  roses  retains  its  purity  of  color ;  the  oil  of  geranium  if  present 
acquires  a  strong  disagreeable  odor,  which  is  very  characteristic. — H.  K.  B. 

OXIDES  are  compounds  containing  oxygen  in  definite  proportions. 

They  are  usually  divided  into  basic  oxides,  which  unite  with  acids ;  acid  oxides,  which 
neutralize  basic  oxides,  combining  with  them  ;  and  neutral  oxides,  which  do  not  unite  with 
either  bases  or  acids.  In  addition  to  these  are  saline  oxides,  or  compounds  which  are  pro- 
duced by  the  union  of  two  oxides  of  the  same  metal. 

OXIDES  for  polishing.  Oxides  of  Iron. — The  finest  crocus  and  rouge  are  thus  prepared. 
Crystals  of  sulphate  of  iron  are  taken  from  the  pans  in  which  they  have  crystallized,  and 
are  put  at  once  into  crucibles,  or  cast-iron  pots,  and  exposed  to  a  high  temperature ;  the 
greatest  care  being  taken  to  avoid  the  presence  of  dust. 

The  least  calcined  portions  are  of  a  scarlet  color,  and  form  the  jeweller's  rouge  for 
polishing  gold  or  silver  articles.  The  more  calcined  portions  are  of  a  purple  or  bluish 
purple  color,  and  these  form  crocus  for  polishing  brass  or  steel.  It  is  found  that  the  blue 
particles,  which  are  those  which  have  been  exposed  to  the  greatest  heat,  are  the  hardest. 
It  will,  of  course,  be  understood  that  the  result  of  the  action  of  heat  is  to  drive  off  the 
sulphuric  acid  from  the  protoxide  of  iron,  which  becomes  peroxidized  in  the  process. 

Lord  Rosse,  in  the  Philosophical  Transactions,  thus  describes  his  process  of  preparing 
his  polishing  powder: — 

"  I  prepare  the  peroxide  of  iron  by  precipitation  with  water  of  ammonia,  from  a  pure 
dilute  solution  of  sulphate  of  iron.  The  precipitate  is  washed,  pressed  in  a  screw-press  till 
nearly  dry,  and  exposed  to  a  heat,  which  in  tlie  dark  appears  a  dull  low  red.  Tlie  only 
points  of  importance  are,  that  the  sulphate  of  iron  should  l)e  pure — and  the  water  of  am- 
monia should  be  decidedly  in  excess,  and  that  the  heat  should  not  exceed  that  I  have 
described.  The  color  will  be  a  bright  crimson,  inclining  to  yellow.  I  have  tried  both  pot- 
ash and  soda  pure,  instead  of  water  of  ammonia,  t)ut  after  washing  with  some  degree  of  care, 
a  trace  of  the  alkali  still  remained,  and  the  peroxide  was  of  an  ochrey  color,  and  did  not 
polish  properly." 

Jeweller's  rouge  is,  however,  frequently  prepared  in  London  by  precipitating  sulphate 
of  iron  with  potash,  well  working  the  yellow  oxide,  and  calcining  it  until  it  acquires  a 
scail  't  color. 

Crocus  is  sometimes  prepared  after  the  manner  recommended  by  Mr.  Heath.  Chloride 
of  sodium  and  sulphate  of  iron  are  well  mixed  in  a  mortar;  the  mixture  is  then  put  into  a 
s'i:<llo'v  crucible  and  exposed  to  a  red  heat.     Vapor  escapes  and  the  mass  fuses.     When  no 


886 


OXIDES  OF  IKON. 


more  vapor  escapes,  remove  the  crucible  and  let  it  cool.  Tlie  color  of  the  oxide  of  iron 
produced,  if  the  fire  has  been  properly  regulated,  is  a  fine  violet — if  the  heat  has  been 
too  high,  it  becomes  black.  The  mass  when  cold  is  to  be  powdered  and  washed,  to  separate 
the  sulphate  of  soda.  The  powder  of  crocus  is  then  to  be  submitted  to  a  process  of  careful 
elutriation,  and  the  finer  particles  reserved  for  the  more  delicate  work. 

OXIDES  OF  IROX.  Four  definite  combinations  of  iron  and  oxygen  are  known 
namely : — 

Protoxide FeO. 

Peroxide  or  sesquioxide Fe^C. 

Black  or  magnetic  oxide Fe^O*=FeO,Fe"0'. 

Ferric  acid FeO^ 

Protoxide,  FeO. — Owing  to  the  rapidity  with  which  this  oxide  attracts  oxygen  from 
the  atmosphere  it  is  almost  unknown  in  a  separate  state.  When  a  solution  of  a  "salt  of  this 
oxide  is  mixed  with  a  solution  of  caustic  alkali,  or  ammonia,  a  bulky  white  precipitate  is 
formed,  which  almost  immediately  begins  to  change  color,  becoming  first  green,  then  red 
brown,  and  when  exposed  freely  to  the  air,  as  in  the  process  of  collecting  and  drying,  it  is 
entirely  converted  into  the  red  brown  sesquioxide. 

It  is  a  powerful  base,  neutralizing  acids  completely,  forming  salts  which  generally  pos- 
sess, when  pure,  a  pale  green  color,  and  a  nauseous  styptic  taste.  This  oxide  is  isomorphous 
with  lime,  magnesia,  oxide  of  zinc,  &c. 

Sraijniuxide,  PVO'. — This  oxide  is  known  in  several  different  forms.  It  is  found  native, 
beautifully  crystallized,  &s  specular  iron  ore,  the  finest  specimens  of  which  are  brought  from 
the  Island  of  Elba  ;  also  as  brown  and  red  hsematites,  the  former  being  a  hydrate.  Rust  of 
iron  is  also  a  sesciuioxide,  containing  variable  cjuantities  of  protoxide. 

It  is  prepared  artificially,  in  the  anhydrous  state,  by  the  ignition  of  ordinary  sulphate  of 
iron,  or  gieen  vitriol,  till  no  more  acid  fumes  are  given  off,  and  is  the  residue  left  in  the 
retorts  in  the  manufacture  of  Nordhausen  oil  of  vitriol,  (see  Sulphuric  Acin.)  After  the 
ignition,  it  is  reduced  to  powder  and  treated  with  water,  when,  after  the  coarser  portions 
have  subsided,  the  water  is  poured  off,  and  allowed  to  stand  for  the  finer  portions  to  de- 
posit. It  is  generally  of  a  bright  red  color,  but  the  color  varies  with  the  degree  of  heat  to 
v.iiich  it  has  been  subjected.  It  is  known  in  commerce  under  various  names,  as  eolcothar, 
trip,  brown-red,  roitr/e,  and  crocus  martix.  That  which  has  the  brightest  color  is  called 
rouge,  and  the  brighter  the  color  the  more  is  it  valued,  if  it  is  also  fine.  It  is  extensively 
used  in  the  steel  manufactures  for  giving  a  finished  lustre  to  fine  articles  ;  it  is  also  employed 
by  silversmiths,  under  the  name  of  plate  powder  and  rouge  ;  and  by  the  opticians  for  polish- 
ing the  specula  of  reflecting  telescopes. 

The  hydrated  oxide,  prepared  by  precipitation  with  ammonia,  is  valuable  in  cases  of  poison- 
ing l)y  arsenic ;  for  it  is  found  to  render  the  arsenic  insoluble  and  therefore  inert.  For  this 
purpose  it  .should  always  be  prepared  by  precipitating  with  ammonia,  as  it  only  requires  about 
a  quarter  the  quantity  thus  prepared  to  what  would  be  required  if  precipitated  by  potash 
or  soda.  It  has  been  found  that  twelve  parts  of  the  moist  ammoniacal  oxide  are  required  for 
every  part  of  arsenic  to  insure  its  full  antidotal  effects.  Dr.  A.  Taylor  says,  that  when  the 
arsenic  is  in  powder  there  is  scarcely  any  effect  produced  ;  but,  nevertheless,  it  has  proved 
beneficial  in  most  cases  of  arsenical  poisoning,  if  given  in  time.  The  arsenious  acid  combines 
with  the  hydrated  oxide  and  forms  an  insoluble  subarsenite  of  iron,  on  the  composition  of 
which  there  are  several  opinions. 

In  the  copperas  and  alum  works,  a  very  large  quantity  of  ochrey  sediment  is  obtained  ; 
which  is  a  se.sijuioxide  of  iron,  containing  a  little  sulphuric  acid  and  alumina.  This 
deposit,  calcined  in  reverherator'y  hearths,  becomes  of  a  bright-red  color,  and  when  ground 
and  elutriated,  in  the  same  way  as  described  under  irhite  lead,  forms  a  cheap  pigment  in 
very  considei-al)le  demand  in  the  French  markel,  called  Eurflia/i  red. 

An  excellent  ])ow(ler  for  applying  to  razor-strops  is  made  by  igniting  together  in  a 
crucible  ecpial  parts  of  well-dried  green  vitriol  and  common  salt.  The  heat  must  be  slowly 
raised  and  well  regulated,  otherwise  the  materials  will  boil  over  in  a  pasty  state,  and  the 
product  in  a  great  measure  be  lost.  When  well  made,  out  of  contact  of  air,  it  has  the 
brilliant  aspect  of  plumbago.  It  has  a  satiny  feel,  and  is  a  true  fer  olec/iste,  similar  in 
composition  to  the  Elba  iron  ore.  It  ref|uires  to  be  ground  and  elutriated  ;  after  which  it 
affords,  on  drying,  an  impalpalde  powder,  that  may  be  either  rubbed  on  a  strop  of  smooth 
buff  leather,  or  mixed  up  with  hog's-lard  or  tallow  into  a  stiff  cerate.  ' 

An  extremely  fine  rouge,  which  will  not  scratch  the  most  delicate  article,  may  be  obtained 
by  first  precipitating  the  protoxalate  of  iron  from  a  solution  of  a  protosalt  of  iron  by  oxalate 
of  potash  ;  this,  when  washed  and  dried,  is  gradually  heated  on  a  sheet  of  iron,  when  it  is 
entirely  converted  into  rouge,  which,  although  not  of  a  very  bright  color,  is  very  fine. 

The  ses(|uioxide  is  a  feeble  ba.«e,  isomorphous  with  alinninn. 

Black  or  Marjticfic  Oxide,  Fe'0'  =  FeO,Fe''0'. — This  oxide  is  also  found  native,  as 
magnetic  iron  ore,  which  in  the  ma.ssive  form  is  called  native  loadstone.  It  is  found  in 
Cornwall,   Devonshire,  Sweden,  &c.     This  iron  ore  occurs  in  different  forms,  as  earthy, 


PAGING  MACHINE.  8b1 

compact,  lamelliform,  and  crystallized  in  the  form  of  the  regular  octahedron.  It  may  be 
prepared  artificially  in  the  hydrated  state,  by  adding  an  excess  of  ammonia,  instantly,  to  a 
mixed  solution  of  a  persalt  and  protosalt  of  iron  in  due  proportions  ;  it  is  obtained  as  a  gray- 
ish black  powder,  which  is  strongly  attracted  by  the  magnet. 

Ferric  Acid,  FeO^ — This  is  only  known  in  combination  with  a  base,  and  the  only  salt 
of  it  which  is  permanent  seems  to  be  the  ferrate  of  baryta,  which  is  a  deep  crimson  powder, 
and  is  formed  by  adding  a  solution  of  a  salt  of  barium  to  the  solution  of  ferrate  of  potash. 
The  ferrate  of  potash  is  formed  by  heating  to  full  redness,  for  an  hour,  in  a  covered 
crucible,  a  mixture  of  one  part  of  pure  sesquioxide  of  iron  and  four  parts  of  dry  nitre.  By 
treating  the  brown,  porous,  deliquescent  mass  thus  formed  with  ice-cold  water,  a  deep 
amethystine  red  solution  of  ferrate  of  jwtash  is  obtained,  which  gradually  decomposes  even 
in  the  cold,  evolving  oxygen  and  depositing  sesquioxide ;  by  heat  it  is  rapidly  decom- 
posed.— H.  K.  B. 

OXYGEX  {Orighie,  Fr. ;  Saucrstoff",  Germ.)  is  a  permanent  gas,  and  is  best  obtained 
by  heating  a  mixture  of  chlorate  of  potash  and  binoxide  of  manganese,  when  the  chlorate 
is  decomposed  into  oxygen  and  chloride  of  potassium,  KC10''=KCl-|-0'*.  Oxygen  may  be 
obtained  from  binoxide  of  manganese  alone  by  the  action  of  heat ,  but  in  this  case,  when 
used  with  chlorate  of  potash,  the  binoxide  seems  only  to  act  in  moderating  the  evolution  of 
oxygen  from  the  chlorate.  When  chlorate  of  potash  alone  is  used  the  evolution  of  gas 
does  not  commence  so  soon,  and  often  is  given  off  rather  suddenly  at  first,  and  may  cause 
the  fracture  of  the  glass  vessel. 

Oxygen  was  first  discovered  by  Dr.  Priestley  in  England,  and  Scheele  in  Sweden,  in 
1774,  about  the  same  time,  but  independently  of  each  other.  Dr.  Priestley  called  it 
(hphlogisticatcd  air,  and  Scheele  empyreal  air.  It  was  Lavoisier  who  gave  it  the  name  of 
oxygen,  from  the  idea  that  it  was  the  acidifying  principle  in  all  acids,  (from  o^vs,  acid,  and 
yeyyd'j),  I  beget,  or  give  rise  to  ;)  but  this  name  has  of  late  years  been  shown  to  be  a  false 
one.  Oxygen  may  be  obtained  from  several  substances,  viz.  by  heating  red  oxide  of  mer- 
cury, HgO  =  Hg-f-0 ;  by  heating  three  parts  of  bichromate  of  potash  with  four  parts  of  oil 
of  vitriol  in  a  glass  retort.  The  products  are  sulphate  of  potash,  sulphate  of  chromium, 
water,  and  oxvgen  : — 

KCr0^^C^0♦+4HS0^=:KS0^+Cr'^3S0'  +  0^. 

Oxygen  is  colorless,  odorless,  tasteless,  incombustible,  but  the  most  powerful  supporter- 
of  combustion.     According  to  Regnault,  100  cubic  inches  of  this  ga.s  weigh,  at  GO"  F.  and 
1)  irometer  at  30  inches,  34"r9  grains,  and  its  specific  gravity  is   1"1056.     According  to 
H.^r/.elius  and  Dulong  its  sp.  gr.  is  1'1026. 

Of  all  known  substances  oxygen  is  the  most  abundant  in  nature,  for  it  constitutes  at 
lea>t  three-fourths  of  the  known  terraqueous  globe.  Water  contains  eight-ninths  of  its 
wjight  of  oxygen  ;  and  the  solid  crust  of  our  globe  probably  consists  of  at  least  one-third 
l)irt  by  weight  of  this  principle  ;  for  silica,  carbonate  of  lime,  and  alumina, — the  three  most 
abundant  constituents  of  the  earth's  strata, — contain  each  about  one-half  their  weight  of 
oxygen.  Oxygen  also  constitutes  about  twenty  per  cent,  by  volume,  or  about  twenty-three 
per  cent,  by  weight,  of  the  atmosphere  ;  and  it  is  an  essential  constituent  of  all  living  beings, 
i'lints,  in  the  sunlight,  absorb  carbonic  acid,  decompose  it — keeping  the  carbon  and 
ii;j;;rating  the  oxj'gen ;  while  animals,  on  the  other  hand,  absorb  oxygen  and  give  off  car- 
lijuic  acid.  Oxygen  is  </te  great  supporter  of  combustion;  substances  which  burn  in  air 
l)urn  with  greatly  increased  brilliancy  in  pure  oxygen.  Several  propositions  have  been 
made  to  produce  intense  light  by  the  use  of  pure  oxygen  gas,  in  the  place  of  atmospheric 
air,  as  the  active  agent  of  combustion.  The  Drummond  Light,  the  Bude  Light,  Fitzmau- 
rice's  Light,  and  others,  employ  oxygen  in  combination  with  carburetted  hydrogen  at  the 
moment  of  entering  into  combustion  ;  and  some  of  these  bring  in  the  additional  aid  of  a 
solid  incandescent  body,  as  lime,  to  increase  the  intensity  of  the  illuminating  power.  The 
employment  of  any  of  these  plans  generally  appears  to  depend  upon  the  production  of  oxy- 
gen bv  some  cheaper  process  than  anv  at  present  emploved. — IL  K.  B. 

OZOKERITE  or  OZOCERITE.  A  mineral  resin  found  in  the  Urpeth  Colliery,  Xew- 
castle-on  Tyne,  at  Uphall  in  Linlithgowshire,  and  in  one  or  two  of  the  collieries  in  South 
Wales.  Its  composition  is  usually  hydrogen  13'79,  carbon  8tj'20.  Jlatchcjine  may  be  re- 
garded as  the  same  substance  ;  the  composition  of  a  specimen  from  Mcrthyr-Tydvil,  analyzed 
by  Johnston,  being,  hydrogen  14-62,  carbon  85'91. 


PAGING  M.YCniNE.  A  self-acting  machine  for  paging  books  and  numbering  docu- 
ments, by  llessrs.  Waterlow  and  Sons,  is  of  a  very  ingenious  character.  The  immbcring 
apparatus  consists  of  five  discs,  which  are  provided  with  raised  figures  on  their  periphery, 
running  from  1,  2,  3,  <S:c.  to  0;  and  these  figures  serve  (like  letter  press  tyjjc)  to  print  the 
numberd  required.     The  discs  are  mounted  at  the  outer  end  of  a  vibraiing  frame  or  arm  on 


888  PALISANDER  WOOD. 

a  comraou  shaft,  to  which  the  first  or  units  disc  is  permanently  fixed  ;  and  tiic  other  four 
discs  (viz.  those  for  marking  tens,  hundreds,  thousands,  and  tens  of  thousands)  aie  niounted 
loosely  thereon,  so  that  they  need  not,  of  necessity,  move  when  the  shaft  is  rotating ;  but 
they  are  severally  caused  to  move  in  the  following  order: — the  tens  disc  performs  one-tenth 
of  a  revolution  for  every  revolution  of  the  units  disc ;  the  hundreds  disc  makes  one-tenth 
of  a  revolution  of  the  tens  disc ;  and  so  on.  As  the  discs  rise  from  the  paper  after  every 
impression,  the  units  disc  is  caused  to  perform  one-tenth  of  a  revolution  (in  order  that  the 
next  number  printed  may  be  a  unit  greater  than  the  preceding  one)  by  a  driving  click  tak- 
ing into  the  teeth  of  a  ratchet-wheel,  fi.\cd  on  the  left-hand  end  of  the  shaft.  The  move- 
ment of  the  other  discs  is  effected,  at  intervals,  by  means  of  a  spring  catch,  affixed  to  the 
side  of  the  units  disc,  and  rotating  therewith ;  which  catch,  each  time  that  the  units  disc 
completes  a  revolution,  is  caused  by  a  projection  on  the  inner  surface  of  the  vibrating  frame 
to  project  behind  one  of  the  raised  figures  on  the  tens  disc,  and  carry  it  round  one-tenth  of 
a  levolution  on  the  next  movement  of  the  units  disc  taking  place ;  and  then,  the  catch 
having  passed  away  from  the  projection,  no  further  increase  in  the  number  imprinted  by 
the  tens  disc  will  bo  effected  until  the  units  disc  has  performed  another  revolution.  Every 
time  that  the  tens  disc  completes  a  revolution,  the  spring  catch  causes  the  hundreds  disc  to 
move  forward  one-tenth  of  a  revolution,  and  similar  movements  are  imparted  to  the  remain- 
ing discs  at  suitable  times.  The  shaft  is  prevented  from  moving  except  when  it  is  acted  on 
by  the  driving  click,  by  a  spring  detent,  or  pull  entering  the  notches  in  the  periphery  of  a 
wheel  fixed  on  the  right-hand  end  of  the  shaft ;  and  thus  the  discs  are  held  steady  while 
numbering,  and  a  clear  and  even  impression  of  the  figure  is  ensured.  The  leaves  of  the 
book  to  be  paged  or  numbered  are  laid  on  the  raised  part  of  the  tal)le  of  the  machine, 
covered  with  vulcanized  India  rubber,  and  as  each  page  is  numbered  it  is  turned  over  by 
the  attendant,  so  as  to  present  a  fresh  page  on  their  next  descent.  As  the  discs  ascend 
after  numbering  each  page,  an  inking  apparatus  (consisting  of  three  rollers  mounted  in  a 
swing  frame,  and  revolving  in  contact  with  each  other,  so  as  to  distribute  the  ink  which  is 
fed  to  the  first  roller  evenly  on  to  the  third  or  inking  roller)  descends  and  inks  the  figures 
which  are  to  be  brought  into  action,  when  the  ntmibering  apparatus  next  descends.  By  this 
means  books  or  documents  may  be  paged  or  marked  with  consecutive  numbers ;  for  print- 
ing duplicate  sets  of  numbers,  as  for  bankers'  books,  a  simple  and  ingenious  contrivance  is 
adopted.  This  consists  in  the  employment  of  an  additional  ratchet-wheel,  which  is  acted  on 
by  the  driving  click  that  moves  the  ratchet-wheel  above  mentioned,  and  is  provided  with  a 
like  number  of  teeth  to  that  wheel.  But  the  diameter  of  the  additional  ratchet-wheel  is 
increased  to  admit  of  the  teeth  being  so  formed  that  the  driving  click  will  be  thereby  held 
back  from  contact  with  every  alternate  tooth  of  the  first-mentioned  ratchet-wheel ;  and  thus 
the  arrangement  of  the  numbering  discs  will  remain  unchanged,  to  give,  on  their  next 
descent,  a  du])licate  impression  of  the  number  previously  printed ;  but,  on  the  re-ascending 
of  the  numbering  appaiatus,  the  click  will  act  on  a  tooth  of  both  ratchet-wheels,  and  move 
both  forward  one-tenth  of  a  revolution  ;  and,  as  the  shaft  accompanies  the  first  ratchet- 
wheel  in  its  movements,  the  number  will  consequently  be  changed. 

Messrs.  Schlesinger  and  Co.  have  introduced  a  paging  machine,  the  capabilities  of  which 
are  similar  to  the  above,  but  somewhat  differently  obtained.  The  numbering  discs  in  this 
instance  are  provided  with  ten  teeth,  with  a  raised  figure  on  the  end  of  each  tooth ;  and 
they  receive  the  change  motion  from  cog  wheels  mounted  below  them  on  the  same  frame. 
At  each  descent  of  the  frame  a  stationary  spring  catch  or  hook  piece  drives  round  the 
wheel  one  tooth,  that  geais  into  the  teeth  of  the  units  disc,  and  thereby  causes  the  units 
disc  to  bring  forward  a  fresh  figure.  The  toothed  wheels  are  .somewhat  narrower  than  the 
numbering  discs,  but  one  tooth  of  each  wheel  is  enlarged  laterally  to  about  double  the  size  of 
the  other  teeth  ;  so  that  at  the  completion  of  every  revolution  of  the  wheel  the  projecting 
tooth  shall  act  upon  a  tooth  of  the  next  disc,  and  carry  that  disc  forward  one-tenth  of  a 
revolution.  By  this  means  the  requisite  movements  of  the  discs  for  effecting  the  regular 
progression  of  the  numbers  are  produced ;  the  first  wheel  driving  its  own  disc,  and  com- 
municating motion  at  intervals  to  the  next  disc,  and  the  other  wheels  each  receiving  motion 
at  intervals  from  the  disc  with  which  it  is  connected,  and  transmitting  motion,  at  still  greater 
intervals  of  time,  to  the  next  disc. 

The  machine  is  caused  to  p.  Int  the  figures  in  duplicate  by  drawing  the  spring  catch  out 
of  action  at  every  alternate  descent  of  the  frame,  and  thereby  preventing  any  change  of  the 
figures  taking  place  until  after  the  next  impression. 

The  numbers  may  be  increased  two  units  at  each  impression,  so  as  to  print  all  even  or 
all  odd  mnnbers,  by  bringing  a  second  catch  into  action,  which  causes  the  unit  disc  to  ad- 
vance one  step  during  the  ascending  movement  of  the  frame,  in  addition  to  the  advance 
duiing  tlie  descent  of  the  same. 

PAIjISAXDER  wood,  a  name  employed  on  the  Continent  for  rosewood.  Iloltzapffel 
has  the  following  remarks  on  this  wood  : — "There  is  considerable  irregularity  in  the  employ- 
ment of  this  name  ;  in  the  work  of  Bergeron  a  kind  of  striped  ebony  is  figured  as  hois  dc  Pali- 
randrc  ;  in  other  French  works  this  name  is  considered  a  synonym  of  iois  violet,  and  stated 
tjn  a  wood  brought  by  the  Dutch  from  their  South  American  colonies,  and  much  esteemed." 


PAPER,  MANUFACTURE  OF. 


889 


PALI^ADIUM.  I'alladium  is  sometimes  substituted  for  silver  in  the  manufacture  of 
mathematical  instruments.  The  commoner  metals  may  be  plated  with  palladium  by  the 
electrotype  process.  Palladium  is  .sometimes  used  in  the  construction  of  accurate  balances, 
and  for  some  of  the  works  of  chronometers.  An  alloy  of  palladium  and  silver  is  employed 
by  the  dentists  from  the  circumstance  that  it  does  not  tarnish.  The  influence  of  palladium 
in  i)rotecting  silver  from  tarnishing  is  a  remarkable  and  valuable  property.  The  WoUaston 
medal  given  bv  the  Geological  Society  is,  in  honor  of  its  discoverer,  made  of  palladium. 

PALMITIC  ACID.  C'-H==0'.  this  acid  was  first  discovered  in  palm  oil,  from  which 
it  derived  its  name  ;  it  has  since  been  found  in  many  other  natural  productions,  and  may 
also  be  manufactured  artificially  from  some  otiier  substances.  It  is  contained,  for  instance, 
in  bees'-wax,  and  that  in  considerable  quantities ;  the  proportion  of  the  wa.\  insoluble  in 
boiling  alcohol  is  called  7ni/ricinc,  and  is  a  palmitate  of  miirici/le.  This  myricme  rccpiires 
a  stronr/  solution  of  potasli  to  saponify  it,  and  then  the  palmitic  acid  is  obtained  as  palmitate 
of  potash,  from  which  it  may  be  separated  by  adding  an  acid. 

Spermaceti  consists  principally  of  a  fat  into  which  this  acid  enters,  viz.,  a  palmitate  of 
cetyle.  The  palmitic  acid  may  be  obtained  from  this  by  dry  distillation.  It  has  Tilso  been 
proved  to  be  contained  in  human  fat. 

It  may  be  obtained  artificially  from  different  substances ;  one  of  which  will  be  sufficient 
to  mention  here,  viz.,  by  fusing  caustic  potash  with  oleic  acid,  avoiding  of  cour.se  too  high 
a  temperature,  and  for  this  purpose  a  few  drops  of  water  are  added  from  time  to  time  to  it. 
Oleic  acid.  Caustic  potash.        Palmitate  of  potash.      Acetate  of  potash.     Hydrogen. 

C=«H-"'0^     +     2(K0,H0)      =      C'-H='KO^      +      C'H^KO*      +      IP. 

The  easiest  and  cheapest  way  of  obtaining  palmitic  acid  is  by  using  palm  oil.  Palm  oil, 
u'lion  fre<h,  consists  principally  of  palmitin  (palmitate  of  glycerine)  and  oleine  ;  but  by  the 
action  of  the  air  and  moisture  it  speedily  changes.  The  fats  become  decomposed  into  the 
fatty  acid.s,  (palmitic  and  oleic,)  with  the  liberation  of  glycerine,  which  is  itself  afterwards 
converted  into  sebacic  acid.  The  palm  oil  is  first  subjected  to  pressure  to  separate  as  much 
as  possible  the  liquid  portions ;  the  solid  residue  is  then  boiled  with  an  all^ali,  and  the  soap 
thus  formed  decomposed  by  an  acid  ;  the  palmitic  acid,  which  thus  separates,  is  then  col- 
lected and  purified  by  several  crystallizations  from  alcohol. 

None  of  these  processes  are  employed  commercially  for  obtaining  palmitic  acid,  which 
is  largely  used  in  making  candles.  When  thus  required  it  is  obtained  in  the  same  manner 
as  stearic  acid,  by  distilling  with  higli-prcssure  steam.     See  Candles. 

When  pure,  palmitic  acid  is  a  colorless  solid  substance,  without  smell,  lighter  than 
water.  It  is  quite  insoluble  in  water,  but  freely  soluble  in  boiling  alcohol  or  ether.  These 
solutions  have  an  acid  reaction,  and  when  concentrated  become  almost  solid  on  cooling ; 
but  if  more  dilute,  the  palmitic  acid  separates  in  groups  of  fine  needles.  It  fuses  at  H3'6° 
J'ahr.,  and  becomes  on  cooling  a  mass  of  brilliant  pearly  scales.  It  may  be  distilled  with- 
out decomposition,  even  without  the  presence  of  steam.  It  unites  with  bases  to  form  salt.s, 
most  of  which  are  insoluble  in  water.  It  may  also  be  made  to  unite  with  glycerine  to  form 
palmitin,  in  which  state  it  previously  existed  in  palm  oil. 

PALMITIN.  As  above  stated,  this  is  the  pi-incipal  constituent  of  fresh  palm  oil.  It 
may  be  obtained  from  it  by  the  following  process  : — The  palm  oil  is  subjected  to  pressure 
to  remove  the  liquid  portions,  the  solid  portion  is  then  boiled  with  alcohol,  which  dissolves 
the  free  fatty  acids  wliich  may  be  present.  The  residue  is  then  crude  palmitin,  and  it  is 
purified  by  repeated  cr3'stallizations  from  ether.  When  thus  obtained  it  is  in  small  crystals ; 
these  fuse  and  become,  on  cooling,  a  semi-transparent  mass,  which  may  be  easily  reduced 
to  powder.  It  is  almost  entirely  insoluble  in  cold  alcohol,  and  only  slightly  solulde  in  boil- 
ing alcohol,  from  which  it  again  separates,  on  cooling,  in  flakes.  It  is  soluble  in  all  pro- 
portions in  boiling  ether. 

PAPER,  MANUFACTURE  OF.  The  nature  of  some  of  the  materials  employed  fir.st 
claims  attention.  Silks,  woollens,  flax,  hemp,  and  cotton,  in  all  their  varied  forms,  whether 
as  cambric,  lace,  linen,  holland,  fustian,  corduroy,  bagging,  canvas,  or  even  as  cables,  are 
or  can  be  used  in  the  manufacture  of  paper  of  one  kind  or  another.  Still,  rags,  as  of 
necessity  they  accunmlate  and  are  gathered  up  by  those  who  make  it  their  business  to 
collect  them,  arc  very  far  from  answering  the  purposes  of  paper  making.  Rags,  to  the 
paper-maker,  are  almost  as  various  in  point  of  quality  or  distinction,  as  the  materials  which 
are  sought  after  through  the  influence  of  fashion,  thus  the  paper-maker,  in  buying  rags, 
requires  to  know  exactly  of  what  the  bulk  is  composed.  If  he  is  a  manufacturer  of  white 
papers,  no  matter  whether  intended  for  writing  or  pi  inting,  silk,  or  woollen  i-ags  would  be 
found  altogether  uscles.s,  ina.smuch  as  it  is  well  known  the  bleach  will  fail  to  act  upon  any 
animal  substance  whatever.  And  although  he  may  piAi'liase  eAcn  a  mixtin-e  in  proper  pro- 
portions adapted  for  the  (juality  he  is  in  the  habit  of  snf)])lying,  it  is  as  essential  in  the 
processes  of  preparation  that  they  shall  previously  be  separated.  Cotton  in  its  raw  state,  as 
may  be  readily  conceived,  requires  far  less  prejiaration  than  a  strong  heniiH'u  fabric,  and 
thus,  to  meet  the  retpjirements  of  the  paper-maker,  rags  are  classed  under  different  deimmi- 
nations,  as  for  instance,  besides _//«rs  and  seconds^  there  are  t/iirJs   wliieh  are  C04n[)osed  of 


890 


PAPER,  MANUFACTUEE  OF. 


fusti;ui3,  corduroy,  and  similar  fabrics ;  stamps  or  prints^  (as  they  are  termed  by  the  paper- 
maker,)  ^vhieh  are  colored  rags,  and  aha  innumerable  foreign  rags,  distinguished  by  certain 
well-known  marks,  indicating  tlieir  various  peculiarities.  It  might  be  mentioned,  however, 
that  although  by  far  the  greater  portion  of  the  materials  employed  are  such  as  have  already 
been  alluded  to,  it  is  not  from  their  possessing  any  exclusive  suitableness — since  various 
fibrous  vegetable  substances  have  frequently  been  used,  and  are  indeed  still  successfully 
employed — but  rather  on  account  of  their  comparatively  trifling  value,  arising  from  the 
limited  use  to  which  they  are  otherwise  applicable. 

To  convey  some  idea  of  the  number  of  substances  which  have  been  really  tried — in  the 
library  of  the  British  Museum  may  be  seen  a  book  printed  in  low  Dutch,  containing  upwards 
of  sixty  specimens  of  paper,  made  of  different  materials,  the  result  of  one  man's  experiments 
alone,  so  far  back  as  the  year  1772.  In  fact,  almost  every  species  of.  tough  fibrous  vege- 
table, and  even  animal  substance,  has  at  one  time  or  another  been  employed :  even  the  roots 
of  trees,  their  bark,  the  vine  of  hops,  the  tendrils  of  the  vine,  the  stalks  of  the  nettle,  the 
common  thistle,  the  stem  of  the  hollyhock,  the  sugar  cane,  cabbage  stalks,  beet-root,  wood 
shavings,  sawdust,  hay,  straw,  willow,  and  the  like.  Straw  is  occasionally  used,  in  connec- 
tion with  other  materials,  such  as  linen  or  cotton  rags,  and  even  with  considerable  advan- 
tage, providing  the  processes  of  preparation  are  thoroughly  understood.  Where  such  is  not 
the  case,  and  the  silica  contained  in  the  straw  has  not  been  destroyed,  (by  means  of  a  strong 
alkali,)  the  paper  will  invariably  be  found  more  or  less  brittle  ;  in  some  cases  so  much  so 
as  to  be  hardly  applicable  to  any  purpose  whatever  of  practical  utility.  The  waste,  how- 
ever, which  the  straw  undergoes,  in  addition  to  a  most  expensive  process  of  preparation,  neces- 
sarily precludes  its  adoption  to  any  great  extent.  Two  inventions  have  been  patented  for 
manufacturing  paper  entirely  from  wood.  One  process  consists  in  first  boiling  the  wood  in 
caustic  soda  lye  in  order  to  remove  the  resinous  matter,  and  then  washing  to  remove  the 
alkali ;  the  wood  is  next  treated  with  chlorine  gas  or  an  oxygenous  compound  of  chlorine 
in  a  suitable  apparatus,  and  washed  to  free  it  from  the  hydrochloric  acid  formed  :  it  is  now 
treated  with  a  small  quantity  of  caustic  soda,  which  converts  it  instantly  into  pulp,  which 
has  only  to  be  washed  and  bleached,  when  it  will  merely  require  to  be  beaten  for  an  hour 
or  an  hour  and  a  half  in  the  ordinary  beating-engine,  and  made  into  paper.  The  other 
invention  is  very  simple,  consisting  merely  of  a  wooden  box  enclosing  a  grindstone,  which 
has  a  roughened  surface,  and  against  which  the  blocks  of  wood  are  kept  in  close  contact  by 
a  lever,  a  small  stream  of  water  being  allowed  to  flow  upon  the  stone  as  it  turns,  in  order 
to  free  it  of  the  pulp,  and  to  assist  in  carrying  it  off  through  an  outlet  at  the  bottom.  Of 
course  the  pulp  thus  produced  cannot  be  employed  for  any  but  the  coarser  kinds  of  paper. 
For  all  writing  and  printing  purposes,  which  manifestly  are  the  most  important,  nothing  has 
yet  been  discovered  to  lessen  the  value  of  rags,  neither  is  it  at  all  probable  that  there  will, 
inasmuch  as  rags  of  necessity  must  continue  accumulating ;  and  before  it  will  answer  the 
purpose  of  the  paper-maker  to  employ  new  material,  which  is  not  so  well  adapted  for  his 
purpose  as  the  old,  he  must  be  enabled  to  purchase  it  for  considerably  less  than  it  would  be 
worth  in  the  maimfacture  of  textile  fabrics;  and  besides  all  this  rags  possess  in  themselves 
the  very  great  advantage  of  having  been  repeatedly  jirepared  for  paper-making  by  the  nu- 
merous alkaline  washings  which  they  necessarily  receive  during  their  period  of  use. 

With  all  the  drawbacks  attending  the  preparation  of  straw,  there  is  certainly  no  fibre  to 
compete  with  it  at  present  as  an  auxiliary  to  that  of  rags.  A  thick  brown  paper,  of  toler- 
able strength,  may  be  made  from  it  cheaply,  but  for  printing  or  writing  purposes  only  an 
inferior  description  can  be  produced,  and  of  little  comparative  strength  to  that  of  rag  paper. 
Its  chief  and  best  use  is  that  of  imparting  stillness  to  common  newspaper.  Some  manu- 
facturers prefer  for  this  purpose  an  intermixture  of  straw  with  paper  shavings,  and  others 
in  place  of  the  paper  shavings  give  the  preference  to  rags.  The  proportion  of  straw  used 
in  connection  with  rags  or  paper  shavings  varies  from  50  to  80  per  cent. 

The  cost  at  the  present  time  of  producing  two  papers  of  equal  quality,  one  entirely  from 
straw,  and  the  other  entirely  from  rags,  would  be  very  nearly  equal ;  for  although  the  cost 
of  the  rags  would  be  at  least  £17  per  ton,  and  the  cost  of  the  straw  not  more  tlian  £2  i)pr 
ton,  in  addition  to  the  greatly  increased  cost  of  preparing  the  straw,  the  rags  would  only 
waste  one-third,  while  the  straw  would  waste  fully  one-half.  Thus  taking  into  consideration 
the  waste  which  each  undergoes  in  process  of  preparation,  the  actual  cost  of  material  in 
producing  a  ton  of  paper  may  be  stated  relatively  as  £25  for  rags,  and  £4  for  straw.  The 
cost,  however,  of  preparation,  which  includes  power,  labor,  and  chemicals,  Ijeing  so  very 
much  greater  in  the  ca.se  of  the  straw, — from  two  to  three  times  as  much  as  that  of  rags — 
a  similarity  of  value  is  thus  ultimately  attained. 

In  order  to  reduce  the  straw  to  a  suitable  consistency  for  paper-making,  it  is  placed  in 
a  boiler,  with  a  large  (|uantity  of  strong  alkali,  and  with  a  pressure  of  steam  equal  to  120 
and  sortketimes  to  150  lbs.  per  square  inch  ;  the  extreme  heat  being  attained  in  super-heat- 
ing the  steam  after  it  leaves  the  boiler,  by  passing  it  through  a  coiled  jjipe  over  a  fire,  and 
thus  the  silica  becomes  destroyed,  and  the  straw  softened  to  pulp,  which,  after  being  freed 
from  the  alkali  Ijy  wa.shing  it  in  cold  water,  is  subsequently  bleached  and  beaten  in  the 
ordinary  rag  engine,  to  which  we  .shall  presently  refer. 


PAPER,  MANUFACTURE  OF. 


891 


The  annual  consumption  of  rags  in  this  country  alone  far  exceeds  120,000  tons,  three- 
fourths  of  whicli  are  imported,  Italy  and  Germany  furnishing  the  principal  supplies.  That 
the  condition  in  which  the  rags  are  imported  furnishes  any  criterion  of  the  national  habits 
of  the  people  from  which  they  came,  as  has  been  frequently  asserted,  however  plausible  in 
theory,  must  at  least  be  received  with  caution. 

All  that  can  be  said  as  to  the  suitableness  of  fibre  in  general,  may  be  summed  up  in 
very  few  words  ;  any  vegetable  fibre  having  a  corrugated  edge,  which  will  enable  it  to 
cohere  in  the  mass,  is  fit  tor  the  purpose  of  paper-making ;  the  extent  to  which  such  might 
be  applied  can  solely  be  determined  by  the  question  of  cost  in  its  production  ;  and  hitherto 
every  thing  which  has  been  proposed  as  a  substitute  for  rags  has  been  excluded  either  by  the 
cost  of  freight,  the  cost  of  preparation,  or  the  expenses  combined. 

In  considering  the  various  processes  or  stages  of  the  manufacture  of  paper,  we  have 
first  to  notice  that  of  carefully  sorting  and  cutting  the  rags  into  small  pieces,  which  is  done 
by  women  ;  each  woman  standing  at  a  table  frame,  the  upper  surface  of  which  consists  of 
very  coarse  wire  cloth  ;  a  large  knife  being  fixed  in  the  centie  of  the  table,  nearly  in  a  vortical 
position.  The  woman  stands  so  as  to  have  the  back  of  the  blade  opposite  to  her,  while  at 
her  right  hand  on  the  floor  is  a  large  wooden  box,  with  several  divisions.  Her  business 
consists  in  examining  the  rags,  opening  the  seams,  removing  dirt,  pins,  needles,  and  buttons 
of  endless  variety,  which  would  be  liable  to  injure  the  machinery,  or  damage  the  quality  of 
the' paper.  She  then  cuts  the  rags  into  small  pieces,  not  exceeding  4  inches  square,  by 
drawing  them  sharply  across  the  edge  of  the  knife,  at  the  same  time  keeping  each  quality 
distinct  in  the  several  divisions  of  the  box  placed  on  her  right  hand.  During  this  process, 
much  of  the  dirt,  sand,  and  so  forth,  passes  through  the  wire  cloth  into  a  drawer  under- 
neath, which  is  occasionally  cleaned  out.  After  this,  the  rags  are  removed  to  what  is  called 
the  dusting  machine^  which  is  a  large  cylindrical  frame  covered  with  similar  coarse  iron 
wire-cloth,  and  having  a  powerful  revolving  shaft  extending  through  the  interior,  with  a 
number  of  spokes  fixed  transversely,  nearly  long  enough  to  touch  the  cage.  By  means  of 
this  contrivance,  the  machiiie  being  fixed  upon  an  incline  of  some  inches  to  the  foot,  the 
rags,  which  are  put  in  at  the  top,  have  any  remaining  particles  of  dust  that  may  still  adhere 
to  them  effectually  beaten  out  by  the  time  they  reach  the  bottom. 

The  rags  being  thus  far  cleansed,  have  next  to  be  boiled  in  an  alkaline  lye  or  solution, 
made  more  or  less  strong  as  the  rags  are  more  or  less  colored,  the  object  being  to  get  rid 
of  the  remaining  dirt  and  some  of  the  coloring  matter.  The  proportion  is  from  four  to  ten 
pounds  of  carbonate  of  soda  with  one-third  of  quick  lime  to  the  hundred  weight  of  material. 
In  this  the  rags  are  boiled  for  several  hours,  according  to  their  quality. 

The  method  generally  adopted  is  that  of  placing  the  rags  in  large  cylinders,  which  are 
constantly,  though  slowly,  revolving,  thus  causing  the  rags  to  be  as  frequently  turned  over, 
and  into  which  a  jet  of  steam  is  cast  with  a  pressure  of  something  near  30  lbs.  to  the  square 
inch. 

After  this  process  of  cleansing,  the  rags  are  considered  in  a  fit  state  to  be  torn  or  macer- 
ated until  they  become  reduced  to  pulp,  which  was  accomplished,  somb  five  and  thirty  or 
forty  years  since,  by  setting  them  to  heat  and  ferment  for  many  days  in  close  vessels, 
whereby  in  reality  they  underwent  a  species  of  putrefaction.  Another  method  subsequent- 
ly employed  was  that  of  beating  them  by  means  of  stamping- rods,  shod  with  iron,  working 
in  strong  oak  or  stone  mortars,  and  moved  by  water-wheel  machinery.  So  rude  and  in- 
eftcctive  however  was  this  apparatus,  that  no  fewer  than  forty  pairs  of  stamps  were  required 
to  operate  a  night  and  a  day  in  preparing  one  hundred  weight  of  material.  At  the  present 
time,  the  average  weekly  consumption  of  I'ags,  at  many  paper  mills,  exceeds  even  30  ton.s. 
The  cylinder  or  engine  mode  of  comminuting  rags  into  paper  pulp  appears  to  have  been 
invented  in  Holland,  about  the  middle  of  the  last  century,  but  received  very  little  attention 
here  for  some  years  afterwards.  The  accompanying  drawing  will  serve  to  convey  some  idea 
of  the  wonderful  rapidity  with  which  the  work  is  at  present  accomplished.  No  less  than 
twelve  toils  per  week  can  now  be  prepared  by  means  of  this  simple  contrivance.  The  hori- 
zontal section  represents  an  oblong  cistern,  of  cast-iron,  or  wood  lined  with  lead,  into 
which  the  rags,  with  a  sufficient  quantity  of  water,  arc  received.  It  is  divided  by  a  paiti- 
tion,  as  shown  (a),  to  regulate  the  course  of  the  stuH';  the  spindle  u]H)n  which  each 
cylinder  c  moves,  extending  across  the  engine,  and  being  {)Ut  in  motion  by  a  band  wheel 
or  pinion  at  the  point  b.  One  cylinder  is  made  to  traverse  at  a  much  swifter  rate  than  the 
other,  in  order  that  the  rags  may  be  the  more  ell'ectually  tritin-atcd.  The  cylinders  c,  as 
shown  in  the  vertical  section,  are  furnished  with  numerous  cuttei's,  running  parallel  to  the 
axis,  and  again  l)eneath  them  similar  cutters  are  moimted  (n)  somewhat  obli(|uely,  against 
which,  when  in  motion,  the  rags  are  drawn  by  the  rai)id  rotation  of  the  cylinders,  and  thus 
reduced  to  the  smallest  filaments  rcfiuisite,  sometimes  not  exc(H'ding  the  sixteenth  of  an 
inch  in  length  ;  the  distance  between  the  fixed  and  movable  blades  being  ca])al)le  of  any 
adjustments,  simply  by  elevating  or  depressing  the  bearings  upon  wliieh  the  necks  of  the 
shaft  are  supported.  AVhcn  iti  o[)eratioM,  it  is  of  course  necessary  to  enclose  the  cylinders 
in  a  case,  as  shov.n,  k  ;  otherwise,  a  large  proportion  of  the  rags  would,  inevitably,  be  thrown 


892 


PAPER,  MANUFACTURE  OF. 
546 


^^'iiiiii^^ 


^ 


out  of  the  engine.  The  rags  are  first  worked  coarsely,  with  a  stream  of  water  running 
through  the  engine,  wliicli  tends  effectually  to  wash  them,  as  also  to  open  their  fibres  ;  and 
in  order  to  carry  off  the  dirty  water,  what  is  termed  a  unsfiinr/  drum  is  frequently  employ- 
ed, consisting  simply  of  a  framework  covered  with  very  fine  wire  gauze,  in  the  interior  of 
which,  connected  with  the  shaft  or  spindle,  which  is  hollow,  are  two  suctions  tubes,  and  by 
this  means,  on  the  principle  of  a  siphon,  the  dirty  water  constantly  flows  away  through  a 
larger  tube  running  down  outside,  which  is  connected  with  that  in  the  centre,  without 
carrying  away'any  of  the  fibre. 

After  this,  the  mass  is  placed  in  another  engine,  where,  if  necessary,  it  is  bleached  by 
an  admixture  of  chloride  of  lime,  which  is  retained  in  the  engine  until  its  action  becomes 
apparent.  The  pulp  is  then  let  down  into  large  slate  cisterns  to  steep,  prior  to  being  re- 
duced to  a  suitable  consistency  by  the  beating  engine,  as  already  described.  The  rolls  or 
cylinders,  however,  of  the  beating  engine  are  always  made  to  rotate  much  faster  than  when 
employed  in  washing  or  bleaching,  revolving  probably  from  120  to  150  times  per  minute; 
and  thus,  supposing  the  cylinders  to  contain  48  teeth  each,  passing  over  eight  others,  as 
shown  in  the  drawing,  effecting  no  fewer  than  103,680  cuts  in  that  short  period.  From 
this  the  great  advantage  of  the  modern,  engine  over  the  old-fashioned  mortar  machine,  in 
turning  out  a  quantity  of  paper  pulp,  will  be  at  once  apparent.  The  introduction  of  color- 
ing matter  in  connection  with  the  paper  manufacture  is  accomplished  simply  by  its  inter- 
mixture with  the  pulp  while  in  process  of  beating  in  the  engine. 

Although  the  practice  of  bluing  paper  is  not,  perhaps,  so  customary  now  as  was  the 
case  a  few  years  back,  the  extent  to  which  it  is  still  carried  may  be  a  matter  of  considerable 
astonishment.  On  its  first  introduction,  when,  as  regards  color,  the  best  paper  was  any  thing 
but  pleasing,  so  striking  a  novelty  would  no  doubt  be  hailed  as  a  great  improvement,  and 
as  such  received  into  general  use;  but  the  superior  delicacy  of  :i  f'r.^t  c'as.s  jiaper  now  made 
without  any  coloring  matter  whatever,  and  without  any  superfluous  marks  on  its  surface,  is 
.so  truly  beautiful  both  in  texture  and  appearance,  as  to  occasion  some  surprise  that  it  is  not 
more  generally  used.* 

Common  materials  are  frequently  and  very  readily  employed,  through  the  assistance  of 
coloring  matter,  which  tends  to  conceal  the  imjierfection.  Indeed  it  would  be  difficult  to 
name  an  instance  of  apparent  deception  more  forciI)le  than  that  which  is  accom{)lished  by 
the  use  of  ultramarine.  Until  very  recently  the  fine  bluish  tinge  given  to  many  writing 
papers  was  derived  fiom  the  admixture  of  that  formerly  expensive,  but  now,  Ijeing  prepared 
artificially,  cheap,  mineral  blue,  (see  Ultramarisk,)  the  oxide  of  cobalt,  generally  termed 

*  See  BicLard  Herring's  "  Pure  Wove  'Writing  Paper." 


PAPER,  MxVNUFACTUPvE  OF.  893 

sinalts,  which  has  still  the  advantajijo  over  the  nltramariiie  of  imparting  a  color  which  will 
endure  for  a  much  longer  pcrioil.  1  pound  of  ultramarine,  however,  going  further  than  4  of 
smalts,  the  former  necessarily  meets  with  more  extended  application,  and  where  the  using 
is  rightly  understood,  and  the  materials  employed  instead  of  being  fine  rags,  comparative 
rubbish,  excessively  bleached,  its  apjjlication  proves  remarkably  serviceable  to  the  paper- 
maker  in  concealing  for  a  time  all  other  irregularities,  and  even  surpassing  iu  appearance 
the  best  papers  of  the  kind. 

At  first  the  introduction  of  iiltramarine  led  to  some  difficulty  in  sizing  the  paper,  for  so 
long  as  smalts  continued  to  be  used,  any  amount  of  alum  might  be  employed,  and  it  was 
actually  added  to  the  size  to  preserve  it  from  putrefaction.  But  since  artificial  ultramarine 
is  bleached  by  alum,  it  became  of  course  necessary  to  add  this  salt  to  the  size  in  veiy  small 
proi)oitions,  and  as  a  natural  consequence  the  gelatine  was  no  longer  protected  from  the 
action  of  the  air,  which  led  to  incipient  decomposition ;  and  in  such  cases  the  putrefaction, 
once  commenced,  proceeded  even  after  the  size  was  dried  on  the  paper,  and  gave  to  it  a 
most  offensive  smell,  which  rendered  the  paper  unsaleable.  This  difficulty,  however,  has 
now  been  overcome,  and  providing  the  size  be  quite  free  from  taint  when  applied  to  the 
paper,  and  quickly  dried,  putrefaction  will  not  subsequently  occur ;  but  if  decay  has  once 
conmienced,  it  cannot  be  arrested  by  drying  only. 

The  operation  of  paper-making,  after  the  rags  or  materials  to  be  used  have  been  thus 
reduced  and  prepared,  may  be  divided  into  two  kinds  :  that  which  is  carried  on  in  hand- 
mills,  where  the  formation  of  the  sheet  is  performed  by  manual  labor ;  and  that  which  is 
carried  on  in  machine-mills,  where  the  paper  is  produced  upon  the  machine  wire-cloth  in 
one  continuous  web. 

With  respect  to  hand-made  papers,  the  sheet  is  formed  by  the  vatman's  dipping  a  mould 
of  fine  wire  cloth  fixed  upon  a  wooden  frame,  and  having  what  is  termed  a  deckle,  to  de- 
termine the  size  of  the  sheet,  into  a  quantity  of  pulp  which  has  been  previously  mixed  with 
water  to  a  requisite  consistency ;  when,  after  gently  shaking  it  to  and  fro  iu  a  horizontal 
position,  the  fibres  become  so  connected  as  to  form  one  uniform  fabric,  while  the  water 
drains  away.  The  deckle  is  then  removed  from  the  mould,  and  the  sheet  of  paper  turned 
off  upon  a  felt,  in  a  pile  with  many  others,  a  felt  intervening  between  each  sheet,  and  the 
whole  subjected  to  great  pressure,  in  order  to  displace  the  superfluous  water  ;  when,  after 
being  dried  and  pressed  without  the  felts,  the  sheets  are  dipped  into  a  tub  of  fine  animal 
size,  the  superfluity  of  which  is  again  forced  out  by  another  pressing ;  each  sheet,  after  being 
finally  dried,  undergoing  careful  examination  before  it  is  finished. 

Tlius  we  have,  first,  what  is  termed  the  water-leaf,  the  condition  in  which  the  paper 
ajipears  after  being  pressed  between  the  felts — this  is  the  first  stage.  Next,  a  sheet  from 
the  bulk,  as  pressed  without  the  felts,  which  still  remains  in  a  state  imfit  for  writing  on,  not 
.  having  been  sized.  Tlicn  a  sheet  after  sizing,  which  completely  changes  its  character  ;  and 
lastly  one  with  the  finished  surface.  This  is  produced  by  placing  the  sheets  separately  be- 
tween very  smooth  copper  plates,  and  then  passing  them  through  rollers,  which  nnpart  a 
pressure  from  20  to  30  tons.  After  only  three  or  four  such  pressures,  it  is  simply  called 
rolled,  but  if  passed  through  more  frequently,  the  paper  acquires  a  higher  surface,  and  is 
then  called  glazed. 

The  paper-making  machine  is  constructed  to  imitate  in  a  great  measure,  and  in  some 
respects  to  improve,  the  processes  used  in  making  paper  by  hand  ;  but  its  chief  advantages 
are  the  increased  rapidity  with  which  it  accomplishes  the  manufacture,  and  the  means  of 
producing  paper  of  any  size  which  can  practically  bo  required. 

By  tlie  agency  of  this  admirable  contrivance,  which  is  so  adjusted  as  to  produce  the 
intended  effect  with  unerring  precision,  a  process  which,  in  the  old  sy.stem  of  paper  makin"-, 
occupied  about  three  weelis,  is  now  performed  in  as  many  miinttcs. 

The  paper-making  machine  is  supplied  fiom  the  "chest"  or  reservoir  f,  into  which  the 
])ulp  descends  from  the  beating  engine,  when  sufficiently  ground  ;  being  kept  in  constant 
motion,  as  it  descends,  ))y  means  of  the  agitator  g,  in  order  that  it  shall  not  settle.  From 
this  reservoir  the;  pulp  is  again  conveyed  by  a  pipe  into  what  is  technically  termed  the 
"lifter"  II,  which  consists  of  a  cast-iron  wheel,  enclosed  in  a  wooden  case,  and  having  a 
number  of  buckets  affixed  to  its  circumference.  The  trough  i,  placed  immediately  beneath 
the  endless  wire  k,  is  for  the  purpose  of  receiving  the  water  which  drains  away  from  the 
pulp  during  the  process  of  manufacture;  and  as  this  water  is  fre(iuently  impregnated  with 
certain  chemicals  usc<l  in  connection  with  pai)er-making,  it  is  rctuiiied  again  by  a  conduct- 
ing spout  into  the  "lifter,"  where,  tjy  the  rotation  of  tlie  buckets,  both  the  pujp  and  back- 
water become  again  thoroughly  mixed,  and  are  together  raised  by  tlie  lifter  tinough  the 
spout  L,  into  the  trough  m,  where  the  pulp  is  strained  by  means  of  a  .sieve  or  "knotler,"  as 
it  is  called,  which  is  usually  formed  of  bras.s,  havir.g  fhie  slits  cut  in  it  to  allow  the  commi- 
nuted pulj)  to  pass  through,  while  it  retains  all  lumps  and  knots  ;  and  so  fine  are  these 
openings,  in  order  to  free  the  pulp  entirely  from  any  thing  which  would  be  lialjlc  to  damage 
tlie  quality  of  the  paper,  that  it  l)ecomcs  necessary  to  a])ply  a  means  of  exhaustion  under- 
Tieath,  in  order  to  facilitate  the  passage  of  the  i)uli)  through  the  strainer. 


894 


TAPER,  MANUFACTURE  OF. 


The  lumps  collected  ii[)on   the  top  of  this  knottcr,  more  particularly  when  printiug 
papers  are  being  manufactured,  are  composed,  to  a  considcralile  extent,  of  india-rubber, 

which  is  a  source  of  much  greater  annoyance  to  the  paper- 
maker  than  is  readily  conceived.  For,  in  the  first  place, 
it  is  next  to  impossible  in  sorting  and  cutting  the  rags  to 
free  them  entirely  from  the  braiding,  and  so  forth,  witn 
which  ladies  adorn  their  dresses;  and  in  the  next,  the 
bleach  failing  to  act  upon  a  substance  of  that  chaiacter, 
^= —  the  quality  of  the  paper  becomes  greatly  deteriorated,  by 
the  large  black  specks  which  it  occasions,  and  which, 
by  the  combined  heat  and  pressure  of  the  rolls  and 
cylinders,  enlarge  considerably  as  it  proceeds. 

Passing  from  the  strainer,  tlie  pulp  is  next  made  to 
distribute  itself  equally  throughout  the  entire  width  of  the 
machine,  and  is  afterwaids  allowed  to  flow  over  a  small 
lip  or  ledge,  in  a  regular  and  even  stream,  whence  it  is 
received  by  the  upper  surfiice  of  the  endless  wire  k,  upon 
which  the  first  process  of  manufacture  takes  place.  Of 
course  the  thickness  of  the  paper  depends  in  some  meas- 
ure upon  the  speed  at  which  the  machine  is  made  to 
travel ;  but  it  is  mainly  determined  by  the  quantity  of 
pulp  allowed  to  flow  upon  the  wire,  wliich  by  various 
contrivances  can  be  regulated  to  great  nicety.  Paper 
may  be  made  by  this  machine,  consideral)ly  less  than 
the  thousandth  of  an  inch  in  thickness,  and  although  so 
thin,  it  is  capable  of  being  colored,  it  is  capable  of  being 
glazed,  it  is  capable  of  receiving  a  water-mark  ;  and  what 
is  perhaps  still  more  astonisliing,  a  strip  not  exceeding  4 
inches  in  width,  is  sometimes  capable  of  sustaining  a 
weight  of  20  lbs.,  so  great  is  its  tenacity. 

But,  to  return  to  the  machine  itself  The  quantity  of 
pulp  required  to  flow  from  the  vat  m  being  determined, 
it  is  first  received  liy  tlie  continuous  wo\en  wire  K,  upon 
which  it  forms  itself  into  paper  ;  thi^  wire  gauze,  which 
resembles  a  jack-towel,  passing  over  the  small  copper 
rollers  n,  round  the  larger  one  marked  o,  iind  behig  kept 
in  proper  tension  by  two  others  placed  underneath.  A 
gentle  vibratory  motion  IVom  side  to  side  is  given  to  the 
wire,  which  assists  to  spread  the  pulp  evenly,  and  also 
to  facilitate  the  seiiaration  of  the  water,  and  by  this 
means,  aided  by  a  suction  pump,  the  p'llp  solidifies  as  it 
advances.  The  two  IjJack  squares  on  either  side  of 
the  "dandy"  roller  p  indicate  the  position  of  two  wood- 
en 'boxes,  from  which  the  air  is  partially  exhausted,  thus 
causing  the  atmospheric  pressure  to  operate  in  compact- 
ing the  pulj)  into  paper,  the  water  and  moisture  being 
drawn  through  the  wire  and  the  pulp  retained  on  the 
surfiice. 

Next,  we  have  to  notice  the  deckle  or  boundary  straps 
Q,  which  regulate  the  width  of  the  paper,  travelling  at  the 
s.ime  rate  as  the  wire,  and  thus  limiting  the  spread  of  the 
pulp.  The  "  dandy  "  roller  p  is  employed  to  give  any 
impression  to  the  paper  that  may  be  required.  We  may 
suppose  for  instance,  that  the  circumference  of  that  roller 
answers  exactly  to  the  length  or  bieadlh  of  the  wire 
forming  a  hand  mould,  which,  supposing  such  wire  to  be 
fixed  or  curved  in  that  form,  wouki  necessarily  leave  the 
same  impression  as  when  em|)loyed  in  the  ordinary  way. 
Being  placed  between  the  air  lioxcs,  the  pa[)er  becomes 
impressed  by  it  when  in  a  half-formed  state,  and  whatever 
marks  are  thus  made,  the  paper  will  effectually  retain. 
The  two  rollers  following  the  dandy,  marked  R  and  o,  are 
termed  couching  rollers,  from  their  performing  a  similar 
operation  in  the  manufacture  of  machine-made  papers  to 
the  business  of  the  coucher  in  conductmg  the  process  by 
hand.  They  are  simply  wooden  rollers  covered  with  felt. 
In  some  instances,  however,  the  upper  couch  roll  r  is  made  to  answer  a  double  purpose. 
In  making  writing  or  other  papers  where  smalts,  ultramarine,  and  various  colors  are  used, 


^       *CI  "*  -r^> 


:ei^ 


/^: 


l;li 


PAPER,  MANUFACTUEE  OF. 


895 


consiJerablo  difference  will  frequently  be  found  in  the  tint  of  the  paper  when  the  two  sides 
are  compared,  in  consequence  of  the  coloring  matter  sinking  to  the  lower  side,  by  the  natu- 
ral subsidence  of  the  water,  or  from  the  action  of  the  suction  boxes ;  and  to  obviate  this, 
instead  of  employing  the  ordinary  couch  roll,  which  acts  upon  the  tcpper  surface  of  the 
paper,  a  hollow  one  is  substituted,  having  a  suction  box  within  it,  acted  upon  by  an  air 
Ijuraj),  wliich  tends  in  some  measure  to  counteract  the  effect,  justly  considered  ol)jection- 
able.  Merging  from  those  rollers  the  paper  is  received  from  the  wire  gauze  by  a  continu- 
ous felt  s,  which  conducts  it  through  two  pair  of  pressing  rollers,  and  afterwards  to  the 
drying  cylinders.  After  passing  through  the  first  pair  of  rollers  the  paper  is  carried  along 
the  felt  for  some  distance,  and  then  turned  over,  in  order  to  receive  a  corresponding  pres- 
sure on  the  other  side,  thus  obviating  the  iuequality  of  surface  which  would  otherwise  be 
apparent,  especially  if  the  paper  were  to  be  employed  for  books. 

The  advantage  gaiued  by  the  use  of  so  great  a  length  of  felt,  is  simply  that  it  becomes 
less  necessary  to  stop  the  machine  for  the  purpo.se  of  washing  it,  than  would  be  the  ca.se  if 
the  felt  were  limited  in  length  to  its  absolute  necessity. 

In  some  instances,  when  the  paper  being  made  is  sized  in  the  pulp  with  such  an 
ingredient  as  j-es-j/j,  the  felt  becomes  so  completely  clogged  in  the  space  of  a  few  hours,  that 
unless  a  very  great  and  apparently  unnecessary  length  of  felt  be  employed,  a  considerable 
waste  of  time  is  constantly  incurred  in  washing  or  changing  the  felt. 

The  operation  of  the  manufacture  will  now  be  apparent.  The  pulp  flowing  from  the 
reservoir  into  the  lifter,  and  thence  tlu'ough  the  strainer,  passes  over  a  small  lip  to  the 
continuous  wire,  being  there  partially  compacted  by  the  shaking,  motion,  more  thoroughly 
so  on  its  passage  over  the  air  boxes,  receiving  any  desired  nuirks  by  means  of  the  dandy 
roller  passing  over  the  continuous  felt  between  the  first  pressing  rollers,  then  turned  over 
to  receive  a  corresponding  pressure  on  the  other  side,  and  from  thence  off  to  the  drying 
cylinders,  which  are  heated  more  or  less  by  injected  steam ;  the  cylinder  which  receives  the 
paper  first,  being  heated  less  than  the  second,  the  second  than  the  third,  and  so  on  ;  the 
paper  after  passing  over  those  cylinders,  being  finally  wound  upon  a  reel,  as  shown,  unless 
it  Ije  printing  paper,  which  can  be  sized  sufficiently  in  the  pulp,  by  an  admixture  of  alum, 
soda,  and  resin,  or  the  like :  in  which  case  it  may  be  at  once  conducted  to  the  cutting 
machine,  to  be  divided  into  auy  length  and  width  required.  But,  supposing  it  to  be  intend- 
ed for  writing  purposes,  it  has  first  to  undergo  a  more  efl'ectual  method  of  sizing,  as  shown 
in  t!ic  accompanying  drawing ;  the  size  in  this  instance  being  made  from  parings  olitained 
ftom  tanners,  curriers,  and  parchment-makers,  as  employed  in  the  case  of  hand-made 
papers.  Of  course,  sizing  in  the  pulp  or  in  the  engine  offers  many  advantages;  but  as 
g'jlatiue,  or  animal  size,  which  is  really  essential  for  all  good  writing  (lualities,  cannot  at 
[iresent  be  employed  during  the  process  of  manufacturing  by  the  machine  without  injury  to 
the  felts,  it  becomes  necessaiy  to  pass  the  web  of  paper,  after  it  has  been  dried  by  the 
cylinders,  through  this  apparatus. 

In  most  cases,  however,  the  paper  is  at  once  guided  as  it  issues  from  the  machine, 
through  the  tub  of  size,  and  is  thence  carried  over  the  skeleton  drums  .shown,  inside  each  of 
which  are  a  number  of  fans  rapidly  revolving ;  sometimes  there  are  forty  or  fifty  of  these 
drums  in  succession,  the  whole  confined  in  a  chamber  heated  by  steam.  A  pa[)er-machine 
with  the  sizing  apparatus  attached,  sometimes  measures,  from  the  wire-cloth  where  the 
pulp  first  flows  on,  to  the  cutting  machine  at  the  extremity,  no  less  than  one  thousand  feet. 
The  advantage  of  drying  the  paper  in  this  manner  over  so  many  of  these  drums  is,  that  it 


turns  out  much  harder  and  stronger,  than  if  dried  more  rapidly  over  heated  cylinders. 
.'<o:ne  tnanufacturers  adopt  a  peculiar  process  of  sizing,  whicii  in  fact  answers  very  nuich 
better,  and  is  alike  api)lical)le  to  papers  made  by  hand  or  l)y  machine,  provided  the  latter 
description  be  first  cut  into  i)ieces  or  siieets  of  the  required  dimensions.  The  contrivanc;' 
consists  of  two  revolving  felts,  l)etween  which  the  sheets  arc  carried  under  several  rollers 
through  a  long  trough  of  size,  being  afterwards  hung  up  to  dry  ui)on  lines,  previously  to 


89G 


PAPER,  MANUFACTURE  OF. 


rolling  or  glazinjj.  The  paper  thus  sized  becomes  much  harder  and  stronger,  ])y  reasons 
of  tlio  freedom  with  wliich  the  sheets  can  contract  in  drying  ;  and  this  is  mainly  the  reason 
why  paper  made  by  hand  continues  to  l)e  so  nmch  tougher  than  that  made  by  the  machine, 
iu  consequence  of  the  natural  tendency  of  the  pulp  to  contract  in  drying,  and  consequently 
becoming,  where  no  resistance  is  offered,  more  entwined  or  entangled,  which  of  course 
adds  very  considerably  to  the  strength  and  durability  of  the  paper.  In  making  by  the 
machine,  this  tendency  is  completely  checked. 

It  may  be  interesting  to  mention,  that  the  first  experiment  for  drying  paper  by  means 
of  heated  cylinders  was  made  at  Gellibrand's  calico  printing  factory,  near  Stepney ;  a  reel 
of  paper,  in  a  moist  state,  having  been  conveyed  there  from  Dartibrd,  iu  a  post  chaise. 
The  experiment  was  tried  in  the  presence  of  the  patentees  of  the  paper  machine  and  Mr. 
Donkin,  the  engineer,  and  proved  highly  satisfoctory,  and  the  adoption  of  copper  cylinders, 
heated  by  steam,  was  thenceforth  considered  indispensable. 

The  next  operation  to  be  noticed,  now  that  the  paper  is  finished,  is  that  of  cutting  it 
into  standard  sizes.  Originally,  the  reel  upon  which  it  was  finally  wound,  was  formed  so 
that  its  diameter  might  be  lessened  or  increased  at  pleasure,  according  to  the  sizes  which 
were  re([uired.  Thus,  for  instance,  supposing  the  web  of  the  paper  was  required  to  be  cut 
into  sheets  of  18  inches  in  length,  the  diameter  of  the  reel  would  be  lessened  to  0  inches, 
and  thus  the  circumference  to  18  inches,  or  if  convenient  it  would  be  increased  to  36  inches, 
the  paper  being  afterwards  cut  into  two  by  hand  with  a  large  knife,  the  width  of  the  web 
being  regulated  by  the  deckle  straps  q,  to  cither  twice  or  three  times  the  width  of  the 
sheet,  as  the  case  might  be.  However,  in  regard  to  the  length,  considerable  waste,  of 
necessity,  arose,  from  the  great  increase  in  the  circumference  of  the  reel  as  the  paper  was 
wound  upon  it,  and  to  remedy  this,  several  contrivances  have  been  invented.  To  dwell 
upon  their  various  peculiarities  or  separate  stages  of  improvement,  would  prove  of  little 
comparative  interest  to  the  general  reader ;  it  will,  therefore,  be  well  to  limit  attention  to 
the  cutting  machine,  of  which  an  illustration  is  given,  which  is  unquestionably  the  best,  as 
well  as  the  most  ingenious,  invention  of  the  kind. 

The  first  movement  or  operation  peculiar  to  this  machine  is  that  of  cutting  the  web  of 
paper  longitudinally,  into  such  widths  as  may  be  required ;  and  this  is  effected  by  means 
of  circular  blades,  placed  at  stated  distances,  wliich  receive  the  paper  as  it  issues  direct  from 


the  other  machinery,  and  by  a  very  swift  motion,  much  greater  than  that  at  which  the 
paper  travels,  slit  it  up  with  unerring  precision  wherever  they  may  be  fixed. 

A  pair  of  those  circular  blades  is  shown  in  the  drawing  a,  the  upper  one  being  much 
larger  than  the  lower,  which  is  essential  to  the  smoothness  of  the  cut.  And  not  only  is  the 
upper  blade  larger  in  circumference,  but  it  is  also  made  to  revolve  with  much  greater 
rapidity,  by  means  of  employing  a  small  pinion,  worked  by  one  at  least  twice  itsdiameter, 
which  is  fixed  upon  the  same  shaft  as  the  lower  blade,  to  which  the  motive  po^er  is  applied. 
The  action  aimed  at  i^  precisely  such  as  we  obtain  from  a  pair  of  scissors. 

The  web,  as  it  is  termed  by  the  paper-maker,  being  thus  severed  longitudinally,  the  next 
operation  is  that  of  cutting  it  off  into  .sheets  of  some  particular  length  horizontally :  and  to 
do  this  re()uires  a  most  ingenious  movement.  To  give  a  very  general  idea  of  the  con- 
trivance, the  dotted  line  represents  the  paper  travelling  on  with  a  rapidity  in  some  cases  of 


PAPER,  MANUFACTURE  OF  897 

80  feet  per  minute,  and  yet  its  course  has  to  be  temporarily  arrested  while  the  required 
separation  is  efloeted,  and  that  too  without  the  paper's  accumulating  in  any  mass,  or  getting 
Cicased  in  the  shghtest  degree. 

The  large  drum  b,  over  which  the  paper  passes,  in  the  direction  indicated  l>y  the  arrows, 
has  simply  an  alternating  motion,  which  serves  to  gather  the  paper  in  stich  lengths  as  may 
be  required ;  the  craidv  arm  c,  which  is  capable  of  any  adjustment  either  at  top  or  bottom, 
regulating  the  extent  of  the  movement  backwards  and  forwards,  and  thus  the  length  of 
the  sheet.  As  soon  as  the  paper  to  be  cut  off  has  passed  below  the  point  d,  at  which  a 
prfsser  is  suspended,  having  an  alternating  motion  given  to  it,  in  order  to  make  it  approach 
to  and  recede  fiom  a  stationary  presser-board,  it  is  taken  hold  of  as  it  descends  from  the 
drum,  and  the  length  pendent  from  the  presser,  is  instantly  cut  off  by  the  movable  knife'  E 
to  which  motion  is  given  by  the  crank  f,  the  connecting  rod  g,  the  lever  ir,  and  the  connect- 
ing rod  I.  The  combined  motion  of  these  rods  and  levers  admits  of  the  movable  knife  e, 
remaining  nearly  quiescent  for  a  given  time,  and  then  speedily  closing  upon  the  fixed  knife 
K,  cutting  o(f  the  paper  in  a  similar  manner  to  a  pair  of  shears,  when  it  immediately  slides 
down  a  board,  or  in  some  instances  is  carried  along  a  revolving  felt,  at  the  extremity  of 
which  several  men  or  boys  are  placed  to  receive  the  sheets,  according  to  the  number  into 
which  the  width  of  the  web  is  divided. 

As  soon  as  the  pressers  are  closed  for  a  length  of  paper  to  be  cut  off,  the  motion  of  the 
gatheiing  drum  is  reversed,  smoothing  out  the  paper  upon  its  surface,  which  is  now  held 
between  the  pressers ;  the  tension  roll  l  taking  up  the  slack  in  the  paper  as  it  accumulates, 
or  rather  bearing  it  gently  down,  until  the  movement  of  the  drum  is  again  reversed  to 
Annish  another  length.  The  handle  m  is  employed  merely  (o  stop  a  portion  of  the  machinery, 
should  the  water-mark  not  fall  exactly  in  the  centre  of  the  sheet,  when  by  this  means  it  can 
be  momentarily  adjusted. 

The  paper  being  thus  made,  and  cut  up  into  sheets  of  stated  dimensions,  is  next  looked 
over  and  counted  out  into  quires  of  24  sheets,  and  afterwards  into  reams  of  20  quires; 
which  subsequently  are  carefully  weighed,  previously  to  their  being  sent  into  the  market. 

Connected  with  the  manufacture  of  paper,  there  is  one  point  of  considerable  interest 
and  importance,  and  that  is,  what  is  commonly,  but  erroneously,  termed  the  water-mark, 
wliich  may  be  noticed  in  the  T'i/Hr.s- newspaper,  in  the  Bank  of  England  Notes,  Cheques,  and 
Bills,  as  also  in  every  Postage  and  Receipt  Label  of  the  present  day. 

The  curious,  and  in  some  instances  absurd  terms,  which  now  puzzle  us  so  much  in  de- 
scribing the  different  sorts  .and  sizes  of  paper,  may  frequently  be  explained  by  reference 
to  the  various  paper  marks  which  have  been  adopted  at  different  periods.  In  ancient  times, 
when  comparatively  few  people  could  read,  pictures  of  every  kind  were  much  in  use  where 
writing  would  now  be  employed.  Every  shop,  for  instance,  had  its  sign,  as  well  as  every 
public-house,  and  those  signs  were  not  then,  as  they  often  are  now,  only  painted  upon  a 
board,  but  were  invariably  actual  models  of  the  thing  which  the  sign  expressed — as  we  still 
occasionally  see  some  such  sign  as  a  bee-hive,  a  tea-canister,  or  a  doll,  and  the  like.  For  tiie 
same  reason  pi-inters  employed  some  device,  which  they  put  upon  the  title-pages  and  at  the 
end  of  their  books,  and  paper-makers  also  introduced  marks,  by  way  of  distinguishing  the 
paper  of  their  manufacture  from  that  of  others  ;  which  marks  becoming  conuuon,  naturally 
gave  their  names  to  difl'erent  sorts  of  paper.  And  since  names  often  remain  long  after  the 
origin  of  them  is  forgotten  and  circumstances  are  changed,  it  is  not  surprising  to  find  the 
old  names  still  in  use,  though  in  some  cases  they  are  not  applied  to  the  same  things  which 
they  originally  denoted.  One  of  the  illustrations  of  ancient  water-marks  given  in  the  ac- 
companying plate,  that  of  an  open  hand  with  a  star  at  the  top,  which  was  in  use  as  early  as 
1530,  i^robably  gave  the  name  to  what  is  called  fiaad  paper,  /.r/.  550. 

Another  very  favorite  paper-mark,  at  a  subsequent  period  1540-GO,  was  the  jug  or  pot 
which  is  also  shown,  /iV/.  551,  and  would  appear  to  have  originated  the  term  pot  paper. 
The  foolscap  was  a  later  device,  and  does  not  appear  to  have  been  nearly  of  such  long 
continuance  as  the  former,  ^'^.  552.  It  has  given  place  to  the  figure  of  Britannia,  or  that 
of  a  lion  rampant,  supporting  the  cap  of  liberty  on  a  pole.  The  name,  however,  has  con- 
tiiaied,  and  we  still  denominate  paper  of  a  jiarticular  size  by  the  title  oi'  foohcap.  The 
original  figure  has  the  cap  and  bells,  of  which  we  so  often  read  in  old  plays  and  histories, 
as  the  particular  head-dress  of  the  fool,  who  at  one  time  formed  part  of  every  great  man's 
establishment. 

The  water-maik  of  a  cap  may  sometimes  be  met  with  of  a  much  simpler  form  than  thatjust 
mentioned — frer|ucntly  resembling  the  jockey  caps  of  the  present  day,  with  a  trilling  orna- 
mentation or  addition  to  tiie  upper  part.  The  first  edition  of  "  Shaks[)eare,"  jjrintcd  by 
laac  Jar/f/ard  <ni(l  K<1.  Bloniif,  1()23,  will  be  found  to  contain  this  mark,  interspersed  with 
several  others  of  a  diirercnt  character.  No  douiit  tlie  general  use  of  the  term  cap  to  various 
papers  of  the  present  day  owes  its  origin  to  marks  of  this  description. 

The  term  iniprrud  was  in  all  probability  derived  from  the  finest  specimens  of  paj)yri 
which  were  so  called  by  the  ancients. 

Post  paper  seems  to  have  derived  its  name  from   the  post  horn,  which  at  one  time  was 
Vol.  III.— 57 


898 


PAPER,  MANUFACTURE  OF. 


its  distinguishing  mark,  fg.  553.     It  does  not  appear  to   have   been   used  prior  to  tlie 
establishment  of  the  general  post-oflBce,  (1670,)  when  it  became  the  custom  to  blow  a  horn, 


652 


550 


55.3 


554 


to  which  circumstance  no  doiibt  we  may  attribute  its  introduction.  The  mark  is  still  fre- 
quently used,  but  the  same  change  which  has  so  much  diminished  the  number  of  painted 
signs  in  the  streets  of  our  towns  and  cities,  has  nearly  made  paper-marks  a  matter  of  anti- 
quarian curiosity ;  the  maker's  name  being  now  generally  used,  and  the  mark,  in  the  few 
instances  where  it  still  remains,  serving  the  purpose  of  mere  ornament,  rather  than  that 
of  distinction. 

Water-maiks,  however,  have  at  various  periods  been  the  means  of  detecting  frauds, 
forgeries  and  impositions,  in  our  courts  of  law  and  elsewhere,  to  say  nothing  of  the  protec- 
tion they  afford  in  the  instances  already  referred  to,  such  as  bank  notes,  cheques,  receipt, 
bill,  and  postage  stamps.  The  celebrated  Curran  once  distinguished  himself  in  a  case  which 
he  had  undertaken  by  shrewdly  referring  to  the  water-mark,  which  encctually  determined 
the  verdict.  And  another  instance,  which  may  be  introduced  in  the  form  of  an  amusing 
anecdote,  occurred  once  at  Messina,  where  the  monks  of  a  certain  monastery  exhibited, 
with  great  triumph,  a  letter  as  being  written  by  the  Viigin  Mary  with  her  own  hand.  Un- 
luckily for  them,  however,  this  was  not,  as  it  easily  might  have  been,  written  upon  the 
ancient  papyrus,  but  on  paper  made  of  rags.  On  one  occasion  a  visitor,  to  whom  this  was 
shown,  observed,  with  affected  solemnity,  that  the  letter  involved  also  a  'Xiiracle,  for  the 
paper  on  which  it  was  written  was  not  in  existence  until  several  centuries  after  the  mother 
of  our  Lord  had  died. 

A  further  illustration  of  the  kind  occurs  in  a  work  entitled  "  Ireland's  Confessions," 
which  was  published  respecting  his  fabrication  of  the  Shakspeare  manuscripts, — a  lite;ary 
forgery  even  still  more  remarkable  than  that  which  is  said  to  have  been  perpetrated  by 
Chatterton,  as  Rowley's  Poems. 

The  interest  which  at  the  time  was  universally  felt  in  this  production  of  Ireland's  may 
be  partially  gathered  from  the  fact,  that  the  whole  of  the  original  edition,  which  appeared 
in  the  form  of  a  shilling  pamphlet,  was  disposed  of  in  a  few  hours  ;  while  so  gieat  was  the 
eagerness  to  obtain  copies  afterwards,  that  single  impressions  were  sold  in  an  auction  room 
at  the  extravagant  price  of  a  guinea. 

This  gentleman  tells  us,  at  one  part  of  his  explanation,  that  the  sheet  of  paper  which  he 
used  wa-s  the  outside  of  several  others,  on  some  of  which  accounts  had  been  kept  in  the 


PAPER,  MANUFACTURE  OF.  bUU 

reign  of  Charles  the  First ;  and  being  at  that  time  wholly  unacquainted  with  the  water-marka 
used  ill  the  reign  of  Queen  Elizabeth,  "  I  carefully  selected  (says  he)  two  lialf  sheets,  not 
having  any  mark  whatever,  on  which  I  penned  my  first  effusion."  A  few  pages  further  on 
he  writes — "  Being  thus  urged  forward  to  the  production  of  more  manuscripts,  it  became 
necessary  that  I  should  possess  a  sufficient  ([uantity  of  old  paper  to  enable  me  to  proceed; 
in  consequence  of  which  I  applied  to  a  bookseller  named  Vei'cy  in  great  May's  Buildings, 
St.  Martin's  Lane,  who,  for  the  sum  of  five  shillings,  suffered  me  to  take  from  all  the  folio 
and  quarto  volumes  in  his  shop  the  fly  leaves  which  they  contained.  By  this  means  I  was 
amply  stored  with  that  commodity;  nor  did  I  fear  any  mention  of  the  circumstance  by  Mr. 
Verey,  whose  quiet,  unsuspecting  disposition,  I  was  well  convinced,  would  never  lead  him 
to  make  the  transaction  public,  in  addition  to  which  he  was  not  likely  even  to  know  any  thing 
concerning  the  supposed  Shaksperian  discovery  by  myself,  and  even  if  he  had,  I  do  not 
imagine  that  my  purchase  of  the  old  paper  in  question  would  have  excited  in  him  the  small- 
est degree  of  suspicion.  As  I  was  fully  aware,  from  the  variety  of  water-marks  which  are 
in  existence  at  the  present  day,  that  they  must  have  constantly  been  altered  since  the 
period  of  Elizabeth,  and  being  lor  some  time  wholly  unacquainted  with  the  water-marks  of  that 
age,  I  very  carefully  produced  my  first  specimens  of  the  writing  on  such  sheets  of  old  paper 
m  had  no  mark  whatever.  Having  heard  it  frequently  stated  that  the  appearance  of  such 
marks  on  the  papers  would  have  greatly  tended  to  establish  their  validity,  I  listened  atten- 
tively to  every  remark  which  was  made  upon  the  subject,  and  from  thence  I  at  length 
gleaned  the  intelligence  that  a  jug  was  the  prevalent  water-mark  of  the  reign  of  Elizabeth, 
in  consequence  of  which  I  inspected  all  the  sheets  of  old  paper  then  in  my  possession,  and 
having  selected  such  as  had  the  jug  upon  them,  I  produced  the  succeeding  manuscripts  upon 
these,  being  careful,  however,  to  mingle  with  them  a  certain  number  of  blank  leaves,  that  the 
production  on  a  sudden  of  so  many  water-marks  might  not  excite  suspicion  in  the  breasts  of 
those  persons  who  were  most  conversant  with  the  manuscripts." 

Thus,  this  notorious  literary  forgery,  through  the  cunning  ingenuity  of  the  perpetrator, 
ultimated  proved  so  successful  as  to  deceive  many  learned  and  able  critics  of  the  age.  In- 
deed, on  one  occasion,  a  kind  of  certificate  was  drawn  up,  stating  that  the  undersigned 
names  were  affixed  by  gentlemen  who  entertained  no  doubt  whatever  as  to  the  validity  of  the 
Shaksperian  production,  and  that  they  voluntarily  gave  such  public  testimony  of  their  con- 
victions upon  the  subject.  To  this  document  several  names  were  appended  by  persons  as 
conspicuous  for  their  erudition  as  they  were  pertinacious  in  their  opinions. 

The  water-mark  in  the  form  of  a  letter  p,  of  which  an  illustiation  is  given  fr/.  554,  was 
taken  from  Caxton's  well-known  work,  "The  Game  of  the  Chess,"  a.  fac-sinule  of  which  has 
recently  been  published  as  a  tribute  to  his  memory.  Paper  was  made  expressly  for  the  pur- 
pose, in  exact  representation  of  the  original,  and  containing  this  water-mark,  which  will  be 
found  connnon  in  works  printed  by  him. 

The  ordinary  mode  of  effecting  such  paper-marks  as  we  have  been  dcsciiliing  is  that  of 
affixing  a  stout  wire  in  the  form  of  any  object  to  be  I'cpresented  to  the  surface  of  the  fine 
wire-gauze,  of  which  the  hand-mould,  or  machine  dandy  roller,  is  constructed. 

The  perfection,  however,  to  which  water-marks  have  now  attained,  wiiich  in  many  in- 
stances is  really  very  beautiful,  is  owing  to  a  more  ingenious  method  recently  patented,  and 
since  adopted  by  the  Bank  of  England,  as  affording  considerable  protection  to  the  public  in 
determining  the  genuineness  of  a  bank-note. 

To  produce  a  line  water-mark  of  any  autograph  or  crest,  we  might  either  engrave  the 
pattern  or  device  first  in  some  yielding  surface,  precisely  as  we  should  engrave  a  copjjer-plate 
for  printing,  and  afterwards,  by  immersing  the  plate  in  a  solution  of  suljjhate  of  copper,  and 
electrotyping  it  in  the  usual  way,  allow  the  interstices  of  the  engraving  to  give  as  it  were  a 
casting  of  pure  copper,  and  thus  an  exact  representation  of  the  original  device,  which,  upon 
being  removed  from  the  plate,  and  affixed  to  the  surface  of  the  wire-gauze  forming  the  mould, 
would  produce  a  corresponding  impression  in  the  paper;  or,  supposing  perfect  identity  to 
be  essential,  as  in  the  e;ise  of  a  l)ank-note,  we  might  engrave  the  design  upon  tlic  surface  of 
a  steel  die,  taking  care  to  cut  those  parts  in  the  die  deepest  which  are  intended  to  give 
greater  effect  in  the  paper,  and  then,  after  having  hardened,  and  otherwise  properly  prepared 
the  die,  it  would  be  placed  under  a  steam  hammer  or  other  stamping  apparatu.s,  for  the 
purpose  of  producing  what  is  technically  termed  a  "  force,"  which  is  lequired  to  assist  in 
transferring  an  impression  from  the  die  to  a  plate  of  sheet  bras.s.  This  being  done,  the  die, 
with  the  mould-plate  in  it,  would  next  be  taken  to  a  perforating  or  cutting  machine,  where 
the  back  of  t!ie  mould-plate — that  is,  the  portion  which  projects  above  the  lace  of  the  die — 
would  be  removed,  while  that  portion  which  was  impressed  into  the  design  engraven  would 
•  remain  untouched,  and  thi.s,  being  subseciuently  taken  from  the  interstices  of  the  die  and 
placed  in  a  frame  upon  a  backing  of  fine  wire-cloth,  becomes  a  mould  for  the  manufacture 
of  paper  of  the  jiattern  which  is  desired,  or  for  the  production  of  any  water-mark,  autograph, 
crest,  or  device,  however  complicated. 

Light  and  shade  are  occasioned  by  a  very  similar  process,  but  one  which  perhaps  recpiircs 
a  little  more  care,  and  necessarily  becomes  somewhat  more  tedious.     For  instance,  in  the 


900 


PAPER,  MANUFACTURE  OF. 


former  case  the  pulp  is  distributed  equally  throughout  the  entire  surface  of  the  wire  forming 
the  mould ;  whereas  7}oio  we  have  to  contrive  the  means  of  increasing  to  a  very  great  nicety 
the  thickness  or  distribution  of  the  pulp,  and  at  the  same  time  to  make  provision  for  the 
water's  draining  away.  This  has  been  accomplislied  by  first  taking  an  electrotype  of  the 
raised  surface  of  any  model  or  design,  and  again  from  that  forming  in  a  similar  manner  a 
matrix  or  mould,  both  of  which  are  suh)sequently  mounted  upon  lead  or  gutta  percha,  in  order 
that  they  may  withstand  the  pressure  which  is  required  to  be  put  upon  them  in  giving  impres- 
sion to  a  sheet  of  very  fine  copper  wire-gauze,  which,  in  the  form  of  a  mould,  and  in  the 
hands  of  the  vatman,  suffices  ultimately  to  produce  those  beautiful  transparent  effects  in 
paper  pirip.  The  word  "  Five  "  in  the  centre  of  the  Bank  of  England  note  is  produced  in  the 
same  maimer.  The  deepest  shadows  in  the  water-mark  being  occasioned  by  the  deepest 
engraving  upon  the  die,  the  lightest  by  the  sliallowest,  and  so  forth  •,  the  die  being  employed 
to  give  impression  by  means  of  the  stamping  press  and  "  force  "  to  the  fine  wire-gauze  itself, 
which  by  this  means,  providing  the  die  be  properly  cut,  is  accomplished  far  more  successfully 
than  by  any  other  process,  and  with  the  additional  advantage  of  securing  perfect  identity. 

It  may  be  interesting  to  call  attention  to  the  contrast  as  regards  the  method  of  mould- 
making  originally  practised,  and  that  wiiich  has  recently  been  adopted  by  the  Bank  of  Eng- 
land. In  a  pair  of  five-pound  note  moulds,  prepared  by  the  old  process,  there  were  8 
curved  borders,  16  figures,  168  large  waves,  and  240  letters,  which  had  all  to  be  separately 
secured  by  the  finest  wire  to  the  waved  surface.  There  were  1,056  wires,  67,584  twists, 
and  the  same  repetition  where  the  stout  wires  were  introduced  to  support  the  tmder  surface. 
Therefore,  with  the  backing,  laying,  large  waves,  figures,  letters,  and  borders,  before  a  pair  of 
moulds  was  completed,  there  wei-e  some  hundreds  of  thousands  of  stitches,  most  of  which 
are  now  avoided  by  the  new  patent.  But  further,  by  this  multitudinous  stitching  and  sew- 
in",  the  parts  were  never  placed  precisely  in  the  same  position,  and  the  water-mark  was  con- 
sequently never  identical.  Now,  the  same  die  gives  impression  to  the  metal  which  transfers 
it  to  the  water-mark,  with  a  certainty  of  identity  unattainable  before,  and  one  could  almost 
say,  never  to  be  surpassed. 

And  may  we  not  detect  principles  in  this  process  which  are  not  only  valuable  to  the 
Bank,  but  to  all  public  establishments  having  impoitaut  documents  on  paper  ;  for  what  can 
exceed  the  value  of  such  a  test  for  discovering  the  deceptions  of  dishonest  men  ?  One's  sig- 
nature crest,  or  device  of  any  kind,  rendering  the  paper  exclusively  one's  own,  can  now  be 
secured  in  a  pair  of  moulds,  at  the  cost  merely  of  a  few  guineas. 

ManufiK'turcd  paper,  independently  of  the  miscellaneous  kinds,  such  as  blotting,  filtering, 
and  the  like,  which  are  rendered  absorbent  l)y  the  free  use  of  woollcit  rags,  may  be  divided 
into  three  distinct  classes,  viz.  writing,  printing,  and  wrapping.  The  former  again  into  five, 
cream  wove,  yellow  wove,  blue  wove,  cream  laid,  and  blue  laid.  The  printing  into  two,  laid 
and  wove,  and  the  latter  into  four,  blue,  purple,  brown,  and  whited  brown,  as  it  is  commonly 
termed. 

To  obtain  a  simple  definition  of  the  mode  adopted  for  distinguishing  the  various  kinds, 
we  must  include,  with  the  class  denominated  irr/t/ug  papers,  those  which  are  used  for  drawing, 
which  being  sized  in  like  manner,  and  with  the  exception  of  one  or  two  larger  kinds,  of 
precisely  the  same  dimensions  as  those  passing  by  the  same  name,  which  are  used  strictly 
for  writing  purposes,  (the  only  distinction,  in  fact,  being,  that  the  drawings  are  cream  wove, 
while  the  writings  are  laid,)  there  would  of  cour.se  be  no  necessity  for  separating  them.  In- 
deed, since  many  of  the  sizes  used  for  printing  are  exactly  the  same  as  those  which  would  be 
named  as  writing  papers,  for  the  sake  of  abridgment  we  will  reduce  the  distinctions  of  dif- 
ference to  but  two  heads,  fine  and  coarse ;  imder  the  latter  including  the  ordinary  brown 
papers,  the  whited  lirown,  or  small  hand  quality,  and  the  blues  and  purples  used  by  grocers. 
The  smallest  size  of  the  fine  quality,  as  sent  f^i-om  the  mill,  measures  12i  by  15  inches, 
and  is  termed  pot;  next  to  that  foolscap,  I6i  by  13 J;  then  post,  18f  by  15^;  copy,  20  by 
16i;  large  post,  20^  by  16A;  medium  post,  18  by  22|-,  shect-and-third  foolscap,  22|  by 
'  13J;  sheet-and-half  foolscap,  24i  by  13^;  double  foolscap,  27  by  17;  double  pot,  15  by 
25  ;  double  post,  30i  by  19  ;  double  crown,  20  by  80  ;  demy,  20  by  loi  ;  ditto  printing,  22^  by 
17f  ;  medium,  22  by  17i;  ditto  printing,  23  by  18^  ;  royal,  24  by  19;  ditto  printing,  25  by 
20;  super  royal,  27  by  19;  ditto  printing,  21  by  27;  imperial,  30  by  22  ;  elephant,  28  by  23  ; 
atlas,  34  by  26 ;  columbier,  34i  by23i^;  double  elephant,  26f  by  40;  and  antiquarian,  53 
by  31.  The  different  sizes  of  letter  and  note  paper  ordinarily  used  are  prepared  from 
those  kinds  by  the  stationer,  whose  business  consists  chiefly  in  smoothing  the  edges  of  the 
paper,  and  afterwards  packing  it  up  in  some  tasteful  form,  which  serves  to  attract  attention. 

Under  the  characteristic  names  of  coarse  papers  may  be  mentioned  Kent  cap,  21  by  18; 
bag  cap,  19A  by  24  ;  Havon  cap,  21  by  26 ;  imperial  cap,  22^  by  29 ;  double  2-lb.,  17  by  24 ; 
dou))le  4-lb.,  21  liy  31  ;  double  6-Ib.,  19  by  28  ;  casing  of  various  dimensions,  also  cartridges, 
with  other  descriptive  names,  besides  middle  hand,  21  by  16  ;  lumber  hand,  19^  by  22i ; 
royal  h.and,  20  by  25;  double  small  hand,  19  l)v  29;  and  of  the  purples,  such  significations 
as"  copy  loaf,  16  j  bv  2If,  38-lb. ;  powder  loaf;  18  by  26,  58-lb.  ;  double  loaf,  16i  by  23, 
48-lb. ;  single  loaf,  2U  by  27,  78-lb. ;  lump,  23  by  33,"  100  lb. ;  llambro',  16^  by  23,'48-lb. ; 


PAPIER-MACHE. 


901 


titler,  20  by  35,  120-lb. ;  Prussian  or  double  lump,  32  by  42,  200-lb. ;  and  so  forth,  with 
glazed  boards  of  various  sizes,  used  chiefly  by  printers  for  pressing,  which  are  manufactured 
iu  a  peculiar  manner  by  hand,  the  boards  being  severally  composed  of  various  sheets  made 
in  the  ordiuary  way,  but  turned  off  the  mould  one  sheet  upon  another,  until  the  required  sub- 
stance be  attained  ;  a  felt  is  then  placed  upon  the  mass  and  another  board  formed.  By  this 
means,  the  slieets,  when  pressed,  adliere  more  effectually  to  each  other,  and  the  boards  con- 
sequently become  much  more  durable  than  would  be  the  case  if  they  were  produced  by 
pasting.  Indeed,  if  any  great  amount  of  heat  be  applied  to  pasteboard.s,  they  will  split, 
and  be  rendered  utterly  useless.     The  glazing  in  this  case  is  accomplished  by  friction. 

To  complete  the  category  of  coarse  papers,  must  be  mentioned  milled  boards,  employ- 
ed in  book-l)inding,  of  not  less  than  150  descriptions,  as  regards  sizes  and  substances. 
Still,  however,  an  incomplete  idea  is  conveyed  of  the  extraordinary  number  of  sizes  and 
descriptions  into  which  paper  is  at  present  divided.  For  instance,  we  have  said  with  refer- 
ence to  writing  qualities,  that  there  are  fne  kinds,  cream  wove,  yellow  wove,  blue  wove, 
cream  laid,  and  Ijlue  laid ;  and  again,  that  of  each  of  those  kinds  there  are  numerous  sizes; 
but  iu  addition  there  are,  as  a  matter  of  course,  various  thicknesses  and  makes  of  each  size 
and  kind.  In  fact,  no  house  in  London,  carrying  on  the  wholesale  stationery  trade,  is  with- 
out a  thousand  different  sorts;  many  keep  stock  of  twice  that  number.* 

The  quantity  of  paper  manufactured  in  this  country  at  the  commencement  of  the  eigh- 
teenth century,  appears  to  have  been  far  from  sufficient  to  meet  the  necessities  of  the  time. 
Even  in  1721,  it  is  supposed  that  there  were  but  about  300,000  reams  of  paper  annually 
produced  in  Great  Britain,  wlfich  were  equal  merely  to  two-thirds  of  the  consumption.  But 
in  1781,  the  value  of  the  paper  manufactured  in  England  alone  is  stated  to  have  amounted 
to  £800,000 ;  and  that,  by  reason  of  the  increase  iu  price,  as  also  of  its  use,  in  less  than 
twentv  years  it  nearly  douliled  that  amount. 

With  a  view  to  greater  exactness,  it  may  be  well  to  append  some  extracts  from  various 
Parliamentary  returns,  relating  to  the  Excise  duties  levied  upon  paper,  which,  since  an 
article  of  tlie  kiud  is  necessarily  subjected  to  great  alteration  in  value,  according  to  the  scar- 
city or  abundance  of  raw  materials,  are,  of  course,  better  calculated  to  show  a  steady  in- 
crease iu  the  demand,  than  any  mere  references  to  statements  of  supposed  value,  from  time 
to  time. — R.  II. 

PAPIER-MACIIE.  The  origin  of  the  manufacture  of  articles  for  use  or  ornament  fiom 
piper,  is  not  very  clearly  made  out ;  we  are  naturally  led  to  believe,  from  the  name,  that 
the  French  must  have  introduced  it.  We  find,  however,  a  French  writer  ascribes  the  merit 
of  producing  paper  ornaments  to  the  English. 

A  kind  of  papier-mache  has  been  introduced,  called  fibrous  slab;  for  the  preparation  of 
this  important  material  the  coar.se  varieties  of  fibre  only  are  required.  These  are  heated 
ami  subjected  to  much  agitation,  to  secure  the  reduction  of  the  fibre  to  the  proper  size. 
This  being  effected,  the  pulp  is  removed  and  subjected  to  the  action  of  the  desiccating 
apparatus,  or  centrifugal  drying  machine.  By  the  means  of  this  apparatus  the  water  is 
diiven,  by  the  action  of  the  centrifugal  force,  from  the  fibre,  and  the  pulp  can  thus  be  ob- 
tained in  a  few  minutes  of  an  equal  and  proper  degree  of  dryness,  and  this  without  the  ap- 
plication of  any  heat.     The  mass  thus  obtained  may  be  regarded  as  a  very  coarse  mixture. 

This  fil)rous  pulp  is  next  combined  with  some  earthy  matter  to  ensure  its  solidity,  and 
certain  chemical  preparations  are  introduced,  for  the  double  pinpose  of  preserving  it  from 
the  attacks  of  insects  and  to  ensure  its  incombustibility.  The  whole  being  mixed  with 
a  cementing  size,  is  well  kneaded  together,  steam  l3cing  applied  during  tlie  process.  While 
the  kneading  process  is  going  forward,  an  iron  table  running  on  wheels  is  properly  adjusted 
and  covered  with  a  sail-cloth;  this  table  being  arranged  so  that  it  passes  under  an  immense 
iron  roller.  The  fibrous  mixture  is  removed  from  the  kneading  troughs  and  is  laid  in  a 
tolera!)ly  miiform  mass  upon  the  sail-cloth,  so  as  to  cover  about  one-half  of  the  table ;  over 
this  again  is  placed  a  length  of  sail-cloth  equal  to  that  of  the  entire  slab,  as  before.  This 
being  done,  the  table  and  roller  are  set  in  action,  and  the  mass  passes  between  them.  It  is 
thus  .squeezed  out  to  a  perfectly  uniform  thickness,  and  is  spread  over  the  whole  table.  The 
fibrous  slab  is  passed  through  the  rollers  .some  thi'ce  or  four  times,  and  it  is  then  drawn  off 
upon  a  frame  fixed  tipon  wheels  prepared  to  receive  it,  by  means  of  which  it  can  be  removed 
to  the  drying  ground.  Tiie  drying  process  of  course  varies  much  with  the  temperature  and 
dryness  of  the  air.  It  does  not  appear  necessary  that  these  slabs  should  dry  too  quickly,  and 
there  are  many  reasons  why  the  pi'ocess  should  not  be  prolonged. 

Wi!  tried  an  experiiTient  upon  the  non-inllainmability  of  this  material,  by  Jiaving  a  fire 
of  wood  made  upon  a  slab  and  maintained  there  some  time.  Wiicn  the  a.she.s,  still  in  a 
state  of  vivid  combustion,  weie  swept  away,  the  slab  was  found  to  l)e  merely  charred  by 
the  inten.sc  heat.  Beyond  this,  a  piece  of  fil)rous  slab  was  thrown  into  the  middle  of  the 
fire,  and  the  flames  were  urged  ui)on  it;  under  the  influence  of  this  intense  action  it  did  not 
appear  possible  to  kindle  it  into  a  flame ;  it  smouldered  veiy  slowly,  the  organic  matter  char- 
ring, but  iu)thing  more. 

*  For  fiiitluir  infortnatiim  upon  this  point,  .soc  tlio  "  rractical  G\iiiie  to  tlie  Variotics  and  Itolatlve 
ValiU'sol"  1'api.T.  '     Lonijiiian  At  Co. 


902  PAPIER-MACHE. 

The  Fihroiis  Slab  Company  is  certainly  producing  a  material  which,  in  many  of  its  appli- 
cations, must  jirove  of  the  greatest  utility,  while  great  additional  value  is  given  to  it  from 
the  ciiciunstaiiee  of  its  resisting  the  attacks  of  insects,  and  being  non-inflammable,  under 
any  of  t'.ie  ordinaiy  operations  of  combustion. 

Pii/tur-MdcIn-  may  be  said,  theretbre,  to  consist  of  three  varieties: — 1.  Sheets  of  paper 
pasted  together,  exposed  to  great  pressure,  and  then  polished;  2.  Sheets  of  considerable 
thickness,  made  from  ordinary  pa[)er  pulp  ;  and  3.  Such  as  we  have  described  in  a  manu- 
facture of  the  fibrous  slab. — E.  J.  II. 

A  new  composition  has  recently  (1858)  been  patented  by  Mr.  John  Cowdery  Martin, 
which  he  designates  a  "  Plastic  compound  for  the  manufacture  of  articles  in  imitation  of 
wood  carvings,  &c."     The  patentee  thus  describes  his  process,  and  the  resulting  material : — 

"  The  object  I  have  had  in  view  is  the  production  of  a  plastic  compound  applicable  to 
the  mainificture  of  moulded  articles,  which,  when  hardened,  resembles  wood  in  the  closeness 
of  its  textuie  and  fibi-ous  character  throughout,  and  is  particulaily  applicable  to  the  manu- 
facture of  articles  intended  to  imitate  wood  carvings.  The  new  manuiacture  may  also  be 
called  ceramic  papier-mache,  from  the  wax-like  character  of  the  compound  when  in  a  soft 
state,  or  belbre  hardening.  The  compound  consists  of  twenty-eight  })iuts  (dry)  by  weight 
of  paper  pnl|),  or  of  any  fibrous  substances  of  which  paper  may  be  made,  reduced  to  pulp 
by  means  of  an  ordinai'y  beating  engine,  or  other  means  used  for  the  manufacture  of  pulp  ; 
twenty  parts  of  resin,  or  rosin,  or  pitch,  or  other  resinous  substance.  I  prefer  resin  or 
rosin ;  ten  parts  of  soda  or  potash,  to  render  the  resin  soluble ;  twenty-four  parts  of  glue, 
twelve  parts  of  drying  oil,  and  one  part  of  acetate  or  sugar  of  lead,  or  other  substances 
capable  of  hardening  or  drying  oil.  The  pulp  after  leaving  the  beating  engine  is  to  be 
diuined  and  slightly  pres.seci  under  a  screw  or  other  press,  to  free  it  partly  from  water.  The 
re.sin  and  alkali  are  then  to  be  boiled  or  heated  together  and  well  mixed.  The  glue  is  to  be 
broken  up  in  pieces  and  melted  in  a  separate  vessel  with  as  much  water  as  will  cover  it,  and 
then  to  V)e  added  to  the  resin  and  alkali,  which  mixtuie  is  then  to  be  added  to  the  pulp  and 
thoroughly  incorporated  with  it.  The  acetate  of  lead  well  mixed  in  the  oil  is  then  to  be 
added,  and  the  whole  mass  or  compound  is  then  to  be  thoroughly  mixed.  The  quantity  of 
resiii  and  alkali,  in  proportion  to  the  glue  used,  miglu  vaiy,  or  glue  might  even  be  dispensed 
with  when  the  acetate  of  lead  would  be  proportionately  increased.  Alter  mixing  the  com- 
pound, it  is  to  remain  exposed  to  the  air  for  three  or  four  days  before  using,  and  to  be  con- 
tinually turned  to  free  it  from  some  of  its  moisture,  for  the  purpose  of  partially  drying,  when 
it  is  to  be  well  kneaded,  and  again  exposed  to  the  air  for  a  few  hours;  and  this  operation 
of  kneading  and  partial  drying  may  be  repeated  until  the  compound  is  considered  to  be 
sufficiently  stiff  and  plastic,  as,  during  the  process  of  kneading  or  working  together,  it 
becomes  extremely  plastic,  resembling  from  this  quality,  when  sufficiently  kneaded,  wax  or 
clay,  and  it  may  then  be  worked,  pressed,  or  moulded  into  any  required  form.  The  com- 
pound may  be  kept  in  a  pla.«tic  state  for  some  weeks,  or  even  months  before  using,  if 
re(|uired,  by  keeping  it  from  exposure  to  the  air  and  occasionally  kneading  or  working  it 
together.  The  moulds  should,  previous  to  pressing  therein  the  compound,  be  brushed  with 
oil,  or  with  oil  in  which  is  mixed  a  little  acetate  of  lead.  The  article  taken  from  the  mould 
is  to  be  thoroughly  dried,  and  afterwards  it  may  be  baked  in  an  oven  at  a  moderate  heat,  the 
temperature  to  be  low  at  first,  and  gradually  increased,  care  being  taken  not  to  scorch  or 
injure  the  filires  of  the  compound.  The  plastic  compound  so  made  and  treated  acquires 
many  of  the  peculiarities  of  wood,  as  regards  hardness  and  strength,  and  it  may  be  cut,  or 
carved  and  poiislieil,  if  required.  Any  color  may  be  added  to  the  compoimd  when  in  a 
soft  stale,  or  two  or  more  portions  of  the  compound,  stained  with  diflerent  colors,  may  be 
worked  together  to  form  a  grain  to  more  nearly  imitate  the  appearance  of  wood.  The  use 
of  the  alkali  being  to  render  the  resinous  substance  sufficiently  soluble  to  combine  with  the 
wet  pulp,  a  more  or  less  quantity  than  that  given  in  proportion  to  the  resin  may  be  used, 
according  to  the  degree  of  solubility  thought  to  be  necessary.  When  potash  is  used,  it  may 
be  dissolved  in  water  before  being  heated  with  the  re<in.  The  quantity  of  glue  may  vaiy, 
and  may  be  increased  to  twice  the  quantity  of  resin,  or  even  more,  or  sufficiently  so  as  to 
dispense  with  the  acetate  of  lead,  as  it  gives  hardness,  and  with  oil  prevents  the  compoimd 
from  sticking;  but  mixed  in  this  manner  it  cannot  be  so  well  kneaded,  and  does  not  retain 
so  fine  an  impression.  I  prefei-  using  with  the  ingredients  as  above  mentioned  the  acetate 
of  lead;  but  half  a  part  by  weight  of  a  solution  of  sulphuric  or  other  acid,  diluted  with 
twenty  times  its  volume  of  water,  may  be  substituted  for  the  one  part  of  acetate  of  lead.  The 
oil  mixeil  with  the  other  ingredients  is  used  to  prevent  the  compound  from  adhering  to  the 
surface  of  the  mouMs,  but  the  less  oil  consistently  with  this  object  that  is  used,  the  better. 
Only  half  the  proportion  of  oil  stated  to  be  used  as  above  may  be  added  at  the  time  of  mix- 
ing the  ingredients  of  the  compound,  and  the  remainder  may  be  added  during  the  process 
of  kneading  or  woiking  up  the  mass.  I  wish  it  to  be  understood,  although  I  prefer  to  use 
resin  or  ro.sin  or  pitch  to  form  the  compound,  that  other  resinous  bodies  soluble  with  alka- 
li''s  in.iy  be  used,  as  the  gums  copal,  nuvtic,  clcmi,  lac,  Canadian  balsam,  Venice  turpentine, 
or  other  resinous  bodies  of  a  like  kind,  either  sepaiately,  or  mixed  according  to  the  facility 


PARCHMENT,  VEGETABLE.  903 

with  which  they  will  combine  with  wet  pulp,  and  the  convenience  with  which  the  compound 
may  be  worked,  as  will  be  well  understood  by  persons  conversant  with  these  substances. 

PARAFFINE;  from  pariim  affinis^  indicating  the  want  of  affinity  which  this  substance 
exhibits  to  most  other  bodies. 

Paraffine  is  a  white  substance,  void  of  taste  and  smell,  feels  soft  between  the  finger.s, 
has  a  specific  gravity  of  087',  melts  at  112"  Fahr.,  boils  at  a  higher  temperature  with  the 
exhalation  of  white  fumes,  is  not  decomposed  by  dry  distillation,  burns  with  a  clear  white 
Hame,  without  smoke  or  residuum,  does  not  stain  paper,  and  consists  of  85-22  carbon,  and 
14-78  hydrogen;  having  the  same  composition  as  oletiant  gas.  It  is  decomposed  neither 
by  chlorine,  strong  acids,  alkalies,  nor  potassium  ;  and  unites  by  fusion  with  sulphur,  pho.-- 
phorus,  wax,  and  rosin.  It  dissolves  readily  in  warm  fat  oils,  in  cold  essential  oils,  and  in 
ether,  but  sparingly  in  boiling  absolute  alcohol.  Paraffine  is  a  singular  solid  bicarburet  of 
hydrogen.     It  has  been  obtained  by  the  destructive  distillation  of  peat. 

The  solid  obtained  is  manufactured  into  beautiful  candles,  not  more  than  300  tons,  how- 
ever, being  employed  annually  in  this  manufacture.  See  Naphtha;  Mineral  Candles; 
Peat;  DrsTrLLATioN,  Destructive. 

PARCHMENT,  VEGETABLE.  Vegetable  parchment  is  made  from  waterleaf  or  un- 
sized paper,  of  which  ordinary  blotting  paper  is  a  common  example,  and  is  well  Adapted 
for  the  process.  This  is  manufactured  from  rags  of  linen  and  cotton,  thoroughly  torn  to 
pieces  in  the  pulping  machine,  and  it  is  found  that  long  fibrous  paper  is  not  so  good  for  the 
production  of  vegetable  parchment  as  that  which  is  napre  thoroughly  pulped.  The  structure 
of  the  waterleaf  may  be  regarded  as  an  interlacement  of  vegetable  fibres  in  every  direction, 
simply  held  together  by  contact,  and  consequently  offering  a  vast  extension  of  surface  lyid 
minute  cavities  to  favor  capillary  action. 

To  make  vegetable  parchment,  the  waterleaf  or  blotting  paper  is  dipped  in  diluted  sul- 
phuric acid,  when  the  change  takes  place,  and  though  nothing  appears  to  be  added  or  sub- 
tracted, the  waterleaf  loses  all  its  previous  properties  and  becomes  vegetable  parchment. 

This  very  remarkable  transformation  is,  however,  a  most  delicate  chemical  process. 
The  strength  of  tlie  acid  must  be  regulated  to  the  greatest  nicety,  for  if  on  the  one  hand  it 
is  too  dilute,  the  fibre  of  the  paper  is  converted  into  a  soluble  substance,  probably  dextrine, 
and  its  paper-like  properties  are  destroyed.  If,  however,  the  acid  be  too  strong,  it  also 
destroys  the  paper  and  renders  it  useless. 

For  the  most  perfect  result,  the  sulphuric  acid  and  water  should  be  at  ordinary  temper- 
ature in  the  proportion  of  about  two  volumes  of  oil  of  vitriol  and  one  volume  of  water,  and 
if  the  paper  be  simply  damped  before  immersion,  the  strength  of  the  acid  is  altered  at  these 
spots,  and  the  part  so  acted  upon  is  destroyed. 

To  make  vegetable  parchment,  the  waterleaf  is  dipped  in  the  sulphuric  acid  exactly 
diluted  to  the  desired  strength,  when  in  the  course  of  a  few  seconds  the  paper  will  be 
observed  to  have  undergone  a  manifest  change,  by  which  time  the  transformation  is  effected 
in  all  its  essential  points.  The  acid  has  then  done  its  work,  and  is  to  be  thoroughly  removed 
from  the  paper,  firstly  by  repeated  washings  in  water,  and  subsequently  by  the  use  of  very 
dilute  ammonia  to  neutralize  any  faint  trace  of  acid  which  escapes  the  washing  in  water. 
All  minute  traces  of  sulphate  of  ammonia  left  by  the  former  process  are  removed  as  fur  as 
possible  by  further  washings,  and  in  certain  cases  the  infinitesimal  trace  of  anmionia  may 
be  removed  by  lime  or  baryta. 

The  action  and  intent  of  these  several  processes  are  to  render  the  vegetable  parchment 
perfectly  free  from  any  acid  or  salt,  and  the  object  is  thoroughly  obtained  in  the  large  way. 

When  the  paper  has  undergone  its  metamorphosis,  it  is  simply  dried,  when  it  becomes 
vegetable  parchment,  differing  from  blotting  paper,  and  possessing  peculiarities  which  sepa- 
rate it  from  every  other  known  material.  The  surfaces  of  the  paper  appear  to  have  under- 
gone a  complete  change  of  structure  and  composition.  All  the  cavities  of  the  waterleaf  are 
closed,  and  the  surface  is  solidified  to  such  an  extent,  that  if  a  portion  of  vegetable  parch- 
ment be  heated  over  a  flame,  blisters  will  occur  from  pent-up  steam,  which  ain;  evolved  in 
the  centre  of  the  paper,  and  even  in  the  aerial  state  tlie  vapor  cannot  pa.ss  cither  surface. 
The  material  of  the  metamorphosed  surfaces  is  certainly  one  of  the  most  unalterable  and 
unchangeable  of  all  known  organic  substances,  and  requires  a  distinctive  name  to  indicate 
its  individuality. 

From  Dr.  llofmann's  report  on  this  remarkable  substance  we  extract  the  following  re- 
marks:— 

"  In  accordance  with  your  request,  I  have  carefully  examined  the  new  material,  called 
vegetable  parchment,  or  parc-hmcnt  paper,  which  you  have  submitted  to  me  for  experiment, 
and  I  now  beg  to  communicate  to  you  the  results  at  which  I  have  arrived. 

"I  may  here  state  that  the  article  in  (luestion  is  by  no  means  new  to  me;  I  became 
acquainted  with  this  remarkable  production  very  soon  after  Mr.  W.  E.  Gaine  had  maile 
known  his  results,  and  I  have  now  .specimens  before  me  which  came  into  my  possession  as 
early  as  1854. 

"The  substance  submitted  to  me  for  examination  exhibits  in  most  of  its  propcritics  so 


904  PARCHMENT,  VEGETABLE. 

close  an  analogy  with  animal  membrane,  that  the  name  adopted  for  the  new  material  seen;-? 
fully  justified.  In  its  appearance,  vegetable  {)arclunent  greatly  resembles  animal  parch- 
ment ;  the  same  peculiar  tint,  the  same  degree  of  transluceucy,  the  same  transition  from  the 
fibrous  to  the  hornlike  condition.  Vegetable,  like  animal  parchment,  possesses  a  high 
degree  of  cohesion,  bearing  i'reciuently-rcpeated  bending  and  rcbending  without  showing 
any  tendency  to  bieak  in  tlie  folds  ;  like  the  latter,  it  is  highly  hygroscopic,  acquiring  by 
the  absorption  of  moisture  increased  flexibility  and  toughness.  Immersed  in  water,  vege- 
table ])archnient  exhibits  all  the  characters  of  animal  membrane,  becoming  soft  and  slippery 
by  the  action  of  the  water,  without,  however,  losing  in  any  way  its  sticngth.  Water  does 
not  percolate  through  vegetable  parchment,  although  it  slowly  traverses  this  substance  like 
animal  membrane  by  cndosmotic  action. 

"In  converting  unsized  paper  into  vegetable  parchment  or  parchment  paper  by  the 
process  recommended  by  Mr.  (iaine,  viz.  immcision  for  a  few  seconds  in  oil  of  vitiiol  dilu- 
ted with  half  its  volume  of  water,  I  was  struck  by  the  observation,  how  narrow  are  the  limits 
of  dilution  between  which  the  experiment  is  attended  with  success.  By  using  an  acid  con- 
taining a  trifle  more  of  water  than  the  proportion  indicated,  tlie  resulting  parchment  is 
exceedingly  imperfect ;  whilst  too  concentrated  an  acid  cither  dissolves  or  chars  the  paper. 
Time,  also,  and  temperature  arc  very  im])ortant  elements  in  the  successful  execution  of  the 
process.  If  the  acid  bath  be  only  slightly  warmer  than  the  common  temperature,  60'  F. 
(1.5o'  C.) — such  as  may  happen  when  the  mixture  of  acid  and  water  has  not  been  allowed 
sufliciently  to  cool — the  effect  is  very  consideiabl  modified.  Nor  do  the  relations  usually 
observed  between  time,  temperature,  and  concentration,  appear  to  obtain  with  reference  to 
this  process ;  for  an  acid  of  inferior  strength,  when  heated  above  the  common  temperature, 
or  allowed  to  act  for  a  longer  time,  entirely  fails  to  produce  the  desired  lesult.  Altogether, 
the  transformation  of  ordinary  paper  into  vcgcta))le  jiarchment  is  an  operation  of  consider- 
able delicacy,  requiring  a  great  deal  of  practice;  in  fact,  it  was  not  until  repeated  failures 
had  pointed  out  to  me  the  several  conditions  involved  in  this  reaction,  that  I  succeeded  in 
producing  papers  in  any  way  similar  to  those  which  you  have  submitted  to  mc  for  expeii- 
ment. 

"  It  is  obvious  that  the  transformation,  under  the  influence  of  sulphuric  acid,  of  paper 
into  vegetable  parchment,  is  altogether  different  from  the  changes  which  vegetable  fibre  suf- 
fers by  the  action  of  nitric  acid  ;  the  cellulose  receiving,  during  its  transition  into  priroxyLin 
and  f/xji-colton,  the  elements  of  hyponitric  acid  in  exchange  for  hydrogen,  whereby  its 
weight  is  raised,  in  some  cases  by  forty,  in  others,  by  as  much  as  sixty  per  cent.  As  the 
nitro-componnds  thus  produced  difler  so  essentially  in  composition  from  the  original  cellu- 
lose, we  are  not  surprised  to  find  them  also  endowed  with  properties  altogether  different ; 
such  as,  increased  combustibility,  change  of  electrical  condition,  altered  deportment  with 
solvents,  &c.,  whilst  vegetable  parchment,  being  the  result  of  a  molecular  transposition  only, 
in  which  the  paper  has  lost  nothing  and  gained  nothing,  retains  all  the  leading  characteis 
of  vegetable  fibre,  exhibiting  only  certain  modifications  which  confer  additional  value  upon 
the  original  substance. 

"  The  nature  of  the  reaction  which  gives  rise  to  the  formation  of  vegetable  parchment 
liaving  been  satisfactorily  established,  it  Ijecame  a  matter  of  importance  to  ascertain  whether 
the  processes  used  for  the  mechanical  removal  of  sulphuric  acid  from  the  paper  had  been 
sufficient  to  produce  the  desired  efi'ect.  It  is  obvious  that  the  valuable  properties  acquired 
by  paper,  by  its  conversion  into  vegetable  parchment,  can  be  permanently  secured  only  by 
the  entire  absence  or  perfect  neutralization  of  the  agent  which  produced  them.  The  pres- 
ence of  even  traces  of  free  sulphuric  acid  in  the  paper  would  rapidly  loosen  its  texture, 
the  paper  would  gradually  fall  to  pieces,  and  one  of  the  most  important  applications  which 
suggest  themselves,  viz.  the  use  of  vegetable  parchment  in  the  place  of  animal  parchment 
for  legal  documents,  would  thus,  at  once,  be  lost.  The  paper  was  found  to  be  entirely 
free  fiom  this  acid. 

"  The  absence  of  free  sulphuric  acid  in  the  parchment  paper  was,  moreover,  established 
by  direct  experiment.  The  most  delicate  test  papers  left  for  hours  in  contact  with  moisten- 
ed vegetable  parchment,  did  not  exliibit  the  slightest  change  of  color.  For  this  purpose, 
bands  of  vegetal )lc  and  of  animal  parchment,  both  I  of  an  inch  in  width,  and  as  far  as  possi- 
ble of  e()ual  thickness,  were  slung  round  an  horizontal  cylinder,  and  appropriately  fixed  by 
means  of  an  screw-clamp  pressing  both  ends  upon  the  upper  part  of  the  cylinder.  The  ban<l 
assumed  in  tliis  manner  the  shape  of  a  ring,  into  the  bend  of  which  a  small  cylinder  of  wood 
was  placed,  projecting  on  each  side  about  an  inch  over  the  band,  and  carrying,  by  means  of 
strings  fastened  to  each  end,  a  ])an  which  was  loaded  with  weights  until  the  band  gave  way. 
A  set  of  experiments  made  in  tliis  inaimer  led  to  the  following  result: — 

Waterleaf  paper  broke,  when  loaded  with 

I.  n.  III.  Mean, 

l^lb.  151b  151b.  15-6lb. 

Vegetable  parchment  broke,  when  loaded  with 

I.  It.  III.  Mean. 

Tslh.  751b.  701b.  '7415. 


PEAT  AND  TURF. 


905 


Animal  parchment  broke,  when  loaded  with 

I.  II.  III.  Mean. 

921b.  TSlb.  5t;lb.  75lb. 

The  strips  of  vegetable  and  animal  parchment  were  selected  as  nearly  as  possible  of 
etpial  thickness,  but  the  strips  of  the  artificial  product  were  somewhat  heavier  than  those  of 
real  parchment.  On  an  average  the  former  weighed  IS  grains,  and  the  latter  only  12'7o 
grains.     Calculated  for  equal  weights,  the  strength  of  animal  parchment,  as  compared  with 

1 8 
that  of  artificial  parchment,  is  obviously       ,  ^   x  75  =  105.     In  round  numbers,  it  may  be 

said  that  vegetable  parchment  has  three-fourths  the  strength  of  animal  parchment." 

PEAT  AXD  TURF.  Accumulations  of  vegetable  matter  may  be  chiefly  composed 
either  of  succulent  vegetation,  gras;^es,  or  marsh  plants,  or  of  trees ;  and  the  structure  and 
condiUon  of  woody  fibre  is  well  known  to  be  very  different  from  that  of  grasses  and 
succulent  plants.  There  are  thus  two  very  distinct  kinds  of  material  preserved,  the  one 
undergoing  change  much  less  rapidly  than  the  other,  and  perhaps  much  loss  completely. 
It  is  easily  proved  that  from  the  accumulation  of  forest  trees  has  been  obtained  the  im- 
perfect coal  called  lignite^  while  from  marsh  plants  and  grasses  mixed  occasionally  with 
wood  we  obtain  peat,  tuif,  and  bog.  All  these  substances  consist  to  a  great  extent  of 
c  irbon,  the  proportions  amounting  to  from  50  to  60  per  cent.,  and  being  generally  greater 
in  lignite  than  in  turf  On  the  other  hand,  the  proportion  of  oxygen  gas  is  generally  very 
much  greater  in  turf  than  in  lignite.  The  proportion  of  ash  is  too  variable  to  be  worth 
recording,  but  is  generally  sufficiently  large  to  injure  the  quality  of  the  fuel. 

As  a  very  large  quantity  of  turf  exists  in  Ireland,  covering,  indeed,  as  much  as  one 
seventh  part  of  the  island,  the  usual  and  important  practical  condition  of  this  substance  can 
be  best  illustrated  by  a  reference  to  that  country.  This  will  be  understood  by  the  following 
account  of  its  origin,  abstracted  from  the  "  Bog  Report"  of  Mr.  Nimmo.  lie  says,  referring 
to  cases  where  clay  spread  over  gravel  has  produced  a  kind  of  puddle  preventing  the 
escape  of  waters  of  floods  or  springs,  and  when  muddy  pools  have  thus  been  formed,  that 
aquatic  plants  have  gradually  crept  in  from  the  borders  of  the  pool  towards  their  deep 
centre.  Mud  accumulated  round  their  roots  and  stalks,  and  a  spongy  semi-fluid  was  thus 
formed,  well  fitted  for  the  growth  of  moss,  which  now  especially  appears ;  Sphagnum 
began  to  luxuriate,  this  absorbing  a  large  quantity  of  water,  and  continuing  to  shoot  out  new 
plants  above,  while  the  old  were  decaying,  rotting  and  compressing  into  a  solid  substance 
below,  gradually  replaced  the  water  by  a  mass  of  vegetable  matter.  In  this  manner  the 
marsh  might  be  filled  up  while  the  central  or  moister  portion,  continuing  to  excite  a  more 
rapid  growth  of  the  moss,  would  be  gradually  raised  above  the  edges,  mitil  the  whole 
surface  had  attained  an  elevation  sufiicient  to  discharge  the  surface  water  by  existing 
channels  of  drainage,  and  calculated  by  its  slope  to  facilitate  their  passage,  when  a  limit 
would  be,  in  some  degree,  set  to  its  further  increase.  Springs  existing  under  the  bog  or 
in  its  immediate  vicinity  might  indeed  still  favor  its  growth,  though  in  a  decreasing 
ratio ;  and  here  if  the  water  proceeding  from  them  were  so  obstructed  as  to  accumulate  at 
its  base,  and  to  keep  it  in  a  rotten  fluid  state,  the  surface  of  the.  bog  might  be  ultimately  so 
raised,  aud  its  continuity  below  so  totally  destroyed,  as  to  cause  it  to  flow  over  the  retain- 
ing obstacle  and  flood  the  adjacent  country.  In  mountain  districts  the  progress  of  the 
phenomenon  is  similar.  Pools  indeed  cannot  in  so  many  instances  be  formed,  the  stoep 
slopes  facilitating  drainage,  but  the  clouds  and  mists  resting  on  the  summits  and  sides  of 
mountains,  amply  supply  their  surface  with  moisture,  which  comes,  too,  in  the  most 
favorable  form  for  vegetation,  not  in  a  sudden  torrent,  but  unceasingly  and  gently,  drop 
by  drop.  The  extent  of  such  bogs  is  also  affected  by  the  nature  of  the  rocks  below  them. 
On  quartz  they  are  shallow  and  small ;  on  any  rock  yielding  by  its  decomposition  a  clayey 
coating  they  are  considerable  ;  the  thickness  of  the  bog,  for  example,  in  Knocklaid  in  the 
county  of  Antrim  (which  is  108  feet  high),  being  neaily  12  feet.  The  summit  bogs  of  high 
mountains  are  distiguishable  from  those  of  lower  levels  by  the  total  absence  of  large  trees. 

As  turf  includes  amass  of  plants  in  different  stages  of  decomposition,  its  aspect  and 
constitution  vary  very  much.  Near  the  surface  it  is  light  colored,  spongy,  and  contains 
the  vegetable  matter  but  little  altered ;  deeper,  it  is  brown,  denser,  and  more  decom- 
posed ;  and  finally  at  the  base  of  the  greater  bogs,  some  of  which  present  a  de]ith  of  40  feet, 
the  mass  of  turf  assumes  the  black  color  and  nearly  the  density  of  coal,  to  which  also  it 
approximates  very  much  in  chemical  composition.  The  amount  of  ash  contained  in  turf 
is  also  variable,  and  appears  to  increase  in  proportion  as  we  descend.  Thus,  in  the  section 
of  a  bog  40  feet  deep  at  Tunahoe,  those  portions  near  the  surface  contained  \h  per  cent, 
of  ashes,  the  centre  portions  Z\  per  cent.,  whilst  the  lowest  four  feet  of  turf  contained 
19  per  cent,  of  ashes.  In  the  superficial  layers  it  may  also  be  remarked,  that  the  coinjio- 
sition  is  nearly  the  same  as  that  of  wood,  the  succulent  material  being  lost,  and  in  the 
lower  we  find  the  change  still  more  complete.  Notwithstanding  these  extreme  variations, 
we  may  yet  establish  the  ordinary  constitution  of  turf,  and  with  certainty  enough  for 
practical  use,  and  on  the  average  specimens  of  turf  selected  from  various  localities,  the 
following  results  have  been  obtained:  — 


906  PEAT  AND  TURF. 

The  calorific  power  of  dry  turf  is  about  half  that  of  coal ;  it  yields,  when  ignited 
with  lead,  about  14  times  its  weight  of  lead.  This  power  is  however  immensely  dimin- 
ished in  ordinary  use  by  the  water  which  is  allowed  to  remain  in  its  texture,  and  which 
the  spongy  character  of  its  mass  renders  it  very  difficult  to  get  rid  of.  There  is  nothing 
which  requires  more  attention  tlian  the  collection  and  preparation  of  turf ;  indeed,  for  prac- 
tical purposes,  this  valuable  fuel  is  absolutely  spoiled  as  it  is  now  prepared  in  Ireland.  It 
is  cut  in  a  wet  season  of  the  year ;  whilst  drying,  it  is  exposed  to  the  weather ;  it  hence  is 
in  reality  not  dried  at  all.  It  is  very  usual  to  find  the  turf  of  commerce  containing  one- 
fourth  of  its  weight  of  water,  although  it  then  feels  dry  to  the  hand.  But  let  us  examine 
what  effects  the  calorific  power.  One  pound  of  pure  dry  tui'f  will  evaporate  6  lbs.  of  water ; 
now,  in  1  lb.  of  turf  as  usually  found,  there  are  f  lb.  of  dry  turf,  and  \  lb.  of  water.  The 
f  lb.  can  only  evaporate  4^  lbs.  of  water ;  but  out  of  this  it  must  first  evaporate  the  ^  lb. 
contained  in  its  mass,  and  hence  the  water  boiled  away  by  such  turf  is  reduced  to  4^  lbs. 
The  loss  is  here  30  per  cent. — a  proportion  which  makes  all  the  difference  between  a  good 
fuel  and  one  almost  unfit  for  use.  When  turf  is  dried  in  the  air  under  cover  it  still  retains 
one-tenth  of  its  weight  of  water,  which  reduces  its  calorific  power  12  per  cent.,  1  lb.  of  such 
turf  evaporating  5^  lbs.  of  water.  This  effect  is  sufficient,  however,  for  the  great  majority 
of  objects ;  the  further  desiccation  is  too  expensive,  and  too  troublesome  to  be  used,  except 
in  special  cases. 

The  characteristic  fault  of  turf  as  a  fuel  is  its  want  of  density,  which  renders  it  difficult 
to  concentrate,  within  a  limited  space,  the  quantity  of  heat  necessary  for  many  operations. 
The  manner  of  heating  turf  is  indeed  just  the  opposite  to  anthracite.  The  turf  yields  a 
vast  body  of  volatile  inflammable  ingredients,  which  pass  into  the  flues  and  chimney,  and 
thus  distribute  the  heat  of  combustion  over  a  great  space,  whilst  in  no  one  point  is  the  heat 
intense.  Hence  for  all  flaming  fires  turf  is  applicable  ;  there  is,  however,  as  some  experi- 
ments made  on  Dartmoor  show,  some  liability  to  that  burning  away  of  the  metal  which  may 
arise  from  the  local  intensity  of  coke.  If  it  be  required,  it  is  quite  possible  to  obtain  a 
very  intense  heat  with  turf. 

The  removal  of  the  porosity  and  elasticity  of  turf,  so  that  it  may  assume  the  solidity  of 
coal,  has  been  the  object  of  many  who  have  proposed  mechanical  and  other  processes  for 
the  purpose.  It  has  been  found  that  the  elasticity  of  the  turf  fibre  presents  great  obstacles 
to  compression,  and  the  black  turf,  which  is  not  fibrous,  is  of  itself  sufficiently  dense. 

Not  merely  may  we  utilize  turf  in  its  natural  condition,  or  compressed  or  impregnated 
pitchy  matter,  but  we  may  carbonize  it,  as  we  do  wood,  and  prepare  turf  charcoal,  the  prop- 
erties of  which  it  is  important  to  establish : — 1.  By  heating  turf  in  close  vessels ;  by  this 
mode  loss  is  avoided,  but  il  is  expensive,  and  there  is  no  compensation  in  the  distilled 
liquors,  which  do  not  contain  acetic  acid  in  any  quantity.  The  tar  is  often  small  in  propor- 
tion, hence  the  charcoal  is  the  only  valuable  product.  Its  quantity  varies  from  30  to  40  per 
cent,  of  dry  turf.  The  products  of  the  distillation  of  1,157  lbs.  of  turf  were  found  by  Bla- 
vier  to  be,  charcoal,  474  lbs.,  or  41  per  cent.  ;  watery  liquid,  226  lbs.,  or  19'3  per  cent.  ; 
gaseous  matter,  4.50  lbs.,  or  39  per  cent. ;  and  tar,  7  lbs.,  or  6  per  cent.  ;  but  the  propor- 
tion of  tar  is  variable,  sometimes  reaching  24-5  per  cent,  when  the  turf  is  coked  in  close 
vessels. 

The  economical  carbonization  of  turf  is  best  carried  on  in  heaps,  in  the  same  manner  as 
that  of  wood.  The  sods  must  be  regularly  arranged,  and  laid  as  close  as  possible  ;  they  are 
the  better  for  being  large,  15  inches  long,  by  6  broad  and  5  deep.  The  heaps  built  hemi- 
spherically  should  be  smaller  in  size  than  the  heaps  of  wood  usually  are.  In  general,  5,000 
or  6,000  large  sods  may  go  to  the  heap,  which  will  thus  contain  1,500  cubic  feet.  The  mass 
must  be  allowed  to  heap  more  than  is  necessary  for  wood,  and  the  process  requires  to  be 
very  carefully  attended  to,  from  the  extreme  combustibility  of  the  charcoal.  The  quantity 
of  charcoal  obtained  in  this  mode  of  carbonization  is  from  25  to  30  per  cent,  of  the  weight 
of  dry  turf. 

For  many  industrial  uses  the  charcoal  so  prepared  is  too  light,  as,  generally  speaking,  it 
is  only  with  fuel  of  considerable  density  that  the  most  intense  heat  can  be  produced,  but  by 
coking  compressed  turf,  it  has  already  been  shown,  that  the  resulting  charcoal  may  attain  a 
density  of  1,040,  which  is  far  superior  to  wood  charcoal,  and  even  equal  to  that  of  the  best 
coke  made  from  coal.  As  to  calorific  effects,  turf  charcoal  is  about  the  same  as  coal  coke, 
and  little  inferior  to  wood  charcoal. 

It  is  peculiarly  important,  in  the  preparation  of  the  charcoal  from  the  turf,  that  the  ma- 
terial sliould  be  selected  as  free  a.s  possible  from  earthy  impurities,  for  all  such  are  concen- 
trated in  the  coke,  which  may  be  thereby  rendered  of  little  comparative  value.  Hence,  the 
coke  from  surface  turf  contains  less  than  10  per  cent,  of  ash,  whilst  that  of  dense  turf  of 
lower  strata  contains  from  20  to  30  per  cent.  This  latter  quantity  might  altogether  unfit  it 
for  practical  purposes. — An.ited. 

Peat  is  cut  and  prepared  in  a  very  simple  manner.  The  surface  matter  being  removed, 
a  peculiar  kind  of  spade  called  a  xlade  is  employed.  This  is  a  long  spade  with  a  portion  of 
the  blade  turned  up  at  right  angles  on  one  side.     With  this  the  turf  is  cut  out  in  the  shape 


PEAT  AND  TURF.  907 

of  thick  bricks  ;  these  are  piled  loosely  against  each  other  to  dry.  The  longer  peat  is  kept, 
and  allowed  to  drv,  the  more  important  it  becomes  as  a  heating  agent. 

On  Durtraoor'the  peat  is  cut  by  the  convicts,  working  in  gangs,  and  being  dried,  it  is 
carefully  stored  in  one  of  the  old  prisons.  From  this  peat,  by  a  most  simple  process,  gas  is 
made,  with  which  the  prisons  at  Prince  Town  are  lighted.  The  illuminating  power  of  this 
gas  is  very  high.  The  charcoal  left  after  the  separation  of  the  gas  is  used  in  the  same  estab- 
lishment for  fuel,  and  for  sanitary  purposes,  and  the  ashes  eventually  go  to  improve  the  cul- 
tivated lands  of  that  bleak  region.  Attempts  were  made  here  many  years  since  to  distil  the 
peat  for  naphtha,  paraffine,  &c.,  but  the  experiments  not  proving  successful,  the  establish- 
ment was  abandoned. 

Experiments  of  a  similar  character  have  be'en  made  in  Ireland,  especially  by  a  company 
working  iinder  the  patents  of  Mr.  Rces  Recce.  A  Government  Commission  made  their  Re- 
port on  these  experiments.  The  whole  matter  was  so  ably  examined  by  Sir  Robert  Kane 
(Director  of  the  Museum  of  Irish  Industry),  and  by  his  assistant.  Dr.  Sullivan,  that  we  quote 
somewhat  largely  from  their  Report. 

The  object  being  to  ascertain  the  necessary  facts  regarding  the  products  of  commercial 
value,  the  following  was  the  course  pursued  : — 

Specimens  of  turf  representing  the  several  ordinary  varieties  were  separately  experi- 
mented on,  and  the  results  examined. 

The  products  of  the  distillation  were  collected  as — 

1.  Charcoal. 

2.  Tar. 

3.  Watery  liquids. 

4.  Gases. 

The  relative  quantities  produced  by  100  parts  of  peat  were  found  to  be— 

Avcrase.  Maximum.  Minimum. 

Charcoal  -         -         -         29-22'2  39-132  18-973 

Tarrv  products         -         -  2-787  4-417  1-4G2 

Watery  products     -         -         31-378  38-127  21-819 

Gases*    -         -         -         -         S«-616  57-746  25-018 

The  peats  yielding  those  proportions  of  products  had  been  found  to  contain  previous  to 
distillation,  as  dried  in  the  air,  a  quantity  of  hygrometric  moisture,  and  to  yield  a  proportion 
of  ashes  in  lUO  parts  as  follows: — 

Averatre.  Maximum.  Minimum. 

Moisture  -         -         -  19-71  29-5(5  lG-39 

Ashes     -         -         -         -  3-43  7-90  '  1-99 

The  several  products  of  the  distillation  thus  carried  on  were  next  specially  examined  for 
the  several  materials  of  which  the  quantities  and  commercial  value  had  been  the  principal 
sources  of  the  public  interest  of  this  infjuiry. 

The  inquiry  having  reference,  however,  to  the  technical  objects  of  the  process,  was 
carried  on  by  examining  the  produce  of 

I.  Tar  for —  1.  Volatile  oils. 

2.  Fixed  (less  volatile)  oils. 

3.  Solid  fats,  or  paraffine. 

4.  Kreosote. 
II.  Watery  liquids  for — 1.  Acetic  acid. 

2.  Ammonia. 

3.  Pyroxylic  spirit. 
III.  Gases  for  illuminating  and  heating  power. 

The  following  numbers  will  indicate  the  results  obtained  in  average.  All  the  details  of 
the  processes  of  separation,  and  the  numbers  of  the  individual  experiments,  were  given  in 
special  reports. 

In  seven  series  of  distillations  in  close  vessels,  there  was  obtained  from  100  parts  of 
peat: — 


Avcrase. 

Minimum. 

Maximum. 

Ammonia 

0-2(>8 

0-181 

0-404 

or  as 

Sulphate  of  ammonia 

1-037 

0-702 

1-567 

Acetic  acid 

0-191 

0-070 

0-286 

or  as 

Acetate  of  Lime 

0-280 

0-111 

0-419 

l^vroxvlic  spirit 

0-14G 

0-092 

0-197 

Viilalile  oils     - 

0-790 

0-571 

1-262 

F'x.'ddils 

0-.5.'')0 

0-266 

0-760 

l':naliine 

0-134 

0-024 

0-196 

908  PEAT  A^'D  TURF. 

It  is-  flius  soon  tliat  the  proportions  of  tliosc  products  vary  within  wide  limits,  wLich  arc 
dctcrnjiiR'd  In  diHciuiicLv-;  ()l'(|u:dity  of  the  turl'  or  temperature  in  the  distilliuiun. 

Several  trials  were  made  to  determine  the  amount  oi"  Urcosote  present  in  the  tar,  but 
glthough  its  presence  could  he  recognized,  its  proportion  was  so  minute  as  to  render  its 
(juautitativc  estimation  in)possihle.  This  circumstance  constitutes  an  essential  distinction 
ot  peat-tar  from  wood-tar,  and  indicates  i'or  the  former  an  infeiior  commercial  v;duc,  as  the 
presence  of  kreosotc,  now  so  extensively  employed,  is  an  clement  m  the  estunato  of  the 
price  of  the  tar  obtained  i)y  distilling  wood. 

"  It  will  be  understood,"  writes  Sir  Robert  Kano,  "  that  the  materials  indicated  in  the 
foregoing  table  by  the  names  'fixed  and  volatile  oils'  are  in  reality  mixtures  of  a  variety  of 
chemical  substances  of  dillerent  volatilities 'and  compositions — generally  carbo-hydrogens 
— of  which  the  further  sejwration  wouhl  be  a  labor  of  purely  scientific  curiosity,  without 
having  any  bearing  upon  the  objects  of  the  present  report.  Although,  therefore,  those 
litpiids  were  carefully  examined,  and  observations  made  regarding  their  chemical  history,  I 
shall  not  embarrass  the  [jresent  repoi-t  by  jcl'erence  to  them  in  any  other  point  of  view  than 
as  products  of  destructive  distillation  whose  properties,  analogous  to  the  highly  volatile  and 
to  the  fixed  oils  resi)ectively,  may  give  them  a  commercial  value  such  as  has  been  represent- 
ed. I  may  remaiiv  also,  that  as  a  purely  scientific  question,  the  true  nature  of  the  solid 
fatty  product  is  of  much  interest.  Tlic  name  parafiine  has  been  given  to  this  body,  but  iu 
some  of  its  characters  it  appears  to  deviate  from  those  of  the  true  parafiine,  as  described  by 
Reichenbach  to  Ije  obtahied  from  wood-tar;  those  differences  should,  however,  not  contra- 
vene its  connnercial  uses."     See  PAnAKFi.NE. 

"The  iucpiiry  so  far  carried  on  sufficiently  established  that  the  peat  by  destructive  dis- 
tillation in  close  vessels  yielded  the  several  products  that  had  been  desciibed,  and  were 
identical,  or  clo.^ely  analogous,  to  those  afforded  in  the  distillation  of  wood  or  coal.  The 
process  in  close  retorts,  however,  being  not  at  all  that  proposed  or  economically  practicable 
lor  commercial  purposes,  it  was  necessary  to  proceed  to  determine  whether  the  same 
varieties  of  peat,  being  distilled  in  a  blast  furnace,  with  a  cuirent  of  air,  so  that  the  heat 
necessary  for  the  distillation  was  produced  by  the  combustion  of  the  peat  itself,  w'ould 
furnish  the  same  products,  and  whether  in  greater  or  in  less  quantities  than  in  the  process 
in  close  vessels. 

"  For  this  purpose,  the  cylinder  which  in  the  former  series  of  experiments  had  been  set 
horizontally  in  the  furnace,  was  placed  surrounded  by  biickwoik  vertically,  its  mouth  pro- 
jecting a  little  at  top,  so  that  the  tube  for  conveying  away  the  products  of  the  distillation 
passed  horizontally  from  the  top  of  the  brickwork  casing  to  the  condensing  apparatus. 
Near  the  bottom  of  the  cylinder  the  brickwork  left  a  space  where  the  cylinder  was  perfo- 
lated  by  an  aperture  1}  inch  diameter,  to  which  the  tube  of  a  large  forge  bellows  was  adapted. 
Tlic  arrangement  thus  represented  nearly  the  construction  of  an  iron  cupola.  The  cylinder 
being  charged  with  peat,  of  which  some  fragments  were  fiist  introduced  lighted,  and  the 
blast  being  put  on,  the  combustion  spread,  and  the  cover  of  the  cylinder  being  screwed  down, 
(he  distillation  proceeded,  the  products  passing  over  with  the  current  of  air  into  the  series 
of  condensing  vessels,  and  the  gases  and  air  finally  being  conducted  by  a  waste  pipe  to  the 
ashi)it  of  a  fin-uace  where  they  were  allowed  to  escape. 

"By  this  means  there  was  obtained,  on  a  moderate  scale,  a  satisf\tctory  representation 
of  the  condition  of  air-blast  distillation  of  peat  which  has  been  proposed  as  the  commercial 
process.  In  so  carrying  it  on  several  interesting  observations  were  made  which  will  require 
to  be  noticed  here  in  a  general  point  of  view. 

"First,  as  to  the  nature  ami  quantities  of  the  products.  The  specimens  of  peat  ope- 
rated on  were  selected  as  similar  to  those  employed  in  the  former  series  of  which  the  results 
have  been  quoted,  and  the  products  similarly  treated  were  found  to  be,  from  100  parts — 

Watery  products     - 
Tarrv  products 
(ia-^cii      - 
Ashes    - 
"  These  several  products  having 
from  100  parts  of  peat — 

Ammonia 

or  as 
Sulphate  of  ammonia 
Acetic  acid 

or  as 
Acetate  of  lime 
Pyroxylic  spirit 
Volatile  oils    - 
Pa:amnc 


Avrrnire. 

Maximum. 

Minimum. 

30-714 

31-678 

29-81 8 

2-392 

2-510 

2-270 

62-392 

65-041 

59-716 

4197 

7-226 

2-493 

li  further 

examined,  as  in 

the  former 

Avpra?e. 

Maximum. 

Minimnra. 

0-2S7 

0-344 

0194 

1-110 

1-330 

0-745 

0-207 

0-268 

0174 

0-305 

0-.S03 

0-256 

0-140 

0-158 

0-106 

1-059 

1-220 

0-946 

0-125 

0-169 

0086 

PEAT  AND  TURF.  909 

"  It  is  now  important  to  compare  these  average  results  with  tnose  of  the  former  series 
obtained  by  distillation  in  close  vessels :  we  obtain — 

Average  produce  from  Average  produce  hy 
close  distillation.        air-blast  distillation. 
Ammonia         -         -         -         0-268  0287 

or  as 
Sulphate  of  ammonia        -         1-037  TllO 

Acetic  acid      -         -         -         0-191  0-207 

or  as 
Acetate  of  lime        -         -         0-280  0-305 

Pyroxylic  spirit        -         -         0-146  0-140 

Oils         -         -         -         -  1-340  1-059 

Paraffine  -         -         -         0134  0-125" 

Experiments  were  made  at  the  request  of  Sir  Robert  Kane,  by  Dr.  Hodges,  Professor 
of  Agriculture,  to  determine  the  commercial  value  of  the  peat  products. 

The  quantities  and  nature  of  the  products,  as  certified  by  Dr.  Hodges,  in  the  one  trial 
which  lie  superintended,  compared  with  the  Museum  average  results  reduced  to  the  same 
standard  (Dr.  Hodges'  acetic  acid  having  been  25  per  cent,  of  real)  are — 


Sulphate  of  ammonia 
Acetic  acid  real  hydrated  - 
Wood  naphtha 
Tar  .... 

It  hence  is  evident  that  the  "quantity  of  ammonia  obtained  at  Xewtown  Crommelin  is 
rather  under  that  obtained  at  the  JIuseum  ;  but  the  produce  of  acetic  acid,  tar,  and  naphtha, 
has  been  found  in  average  decidedly  inferior  to  that  stated,  although  the  maximum  results 
found  in  particular  trials  have  approximated  closely  to  Dr.  Hodges'  numerical  results. 
There  having  been,  however,  apparently  but  a  single  trial  so  accurately  followed  up  at 
Newtown  Crommelin,  it  is  necessary  to  contrast  the  results  of  the  Museum  experiments 
more  specially  with  the  quantitative  produce  expected  by  Mr.  Rcece. 

Mr.  Recce's  statement  of  the  produce  from  100  tons  of  peat  distilled  is  compared  with  the 
average  results  of  the  Museum  trials  in  the  following  table  : — 


Professor  Ilodcres. 

Mus 

?um. 

From  100 

From  100 

From  a  ton.           parts. 

From  a  ton. 

parts. 

22 1  lbs.            1-000 

247io  lbs. 

1-110 

7i  lbs.              -328 

4J      lbs. 

-207 

831  oz.               ^232 

50'/5     oz. 

•140 

99*  lb.s.           4-440 

53|      lbs. 

2-390 

Statement  in 

Average  results  of 

From 

Mr.  Keece's 

Museum  trials  by 

100  parts  of  peat. 

prospectus. 

blast  process. 

Sulphate  of  ammonia  - 

1-000 

1-110 

Acetate  of  lime  - 

•700 

•305 

Wood  naphtha    - 

•185 

-140 

Paraffine    - 

•104 

•125 

Fixed  oils  - 

•714  ) 

1-059 

Volatile  oils 

•357  f 

From  this  comparison  it  is  evident  that  the  quantity  of  ammonia  obtained  is  rather 
greater  than  that  expected  by  Mr.  Reecc ;  secondly,  that  the  quantity  of  paraffine  and  of  oils 
may  be  considered  the  same ;  thirdly,  that  the  quantity  of  wood-naphtha  expected  by  Mr. 
Reece  is  more  than  was  obtained  in  average,  but  not  more  than  was  obtained  in  some  Muse- 
um trials.  That  the  quantity  of  acetate  of  lime  expected  by  Mr.  Reece  is  more  than  double 
that  which  was  in  average  obtained  in  the  Museum,  unless  the  commercial  acetate  of  lime 
calculated  for  by  Mr.  Reece  shall  contain  such  excess  of  lime,  &c.,  as  shall  render  its  weight 
double  that  which  the  pure  article,  calculated  in  the  result  of  the  Museum  trials,  should 
have.     This  latter  circumstance  may  possibly  explain  the  difference. 

After  a  minute  detail  of  the  numerous  experiments  made  by  Dr.  W.  Sullivan,  in  the 
Laboratory  of  the  Museum  of  Irish  Industry,  Sir  Robert  Kane  gives  the  following  summary 
of  his  results  : — 

"From  these  considerations  of  the  results  of  the  experiments  made  in  the  Museum  of 
Industry,  and  the  trials  at  Newtown  Crommelin,  and  of  the  circumstance*  of  the  manufac- 
ture of  the  same  products  from  the  other  species  of  fuels  by  proces.ses  more  or  less  analogous, 
it  appears  to  me  that  some  general  conclusions  may  be  deduced : — 

"  1.  That  the  quantities  of  ammonia,  of  wood  spirit,  and  of  so-called  paraffine,  lixed  and 
volatile  oils,  stated  by  Mr.  Reece  to  l)e  obtaineii  by  distillation  from  peat,  do  not  apjicar  to 
be  exaggerated,  as  they  fall  within  the  limits  of  the  results  obtained  in  the  JIu.scum  labora- 
tory, and  approach  elo.sely  to  the  average  results.  That  the  (juantity  of  acetic  acid  or 
acetate  of  lime,  stated  by  Mr.  Recce  and  Dr.  Hodges,  could  not  be  obtained,  the  result  of 
the  Museum  trials  affording  but  from  one-half  to  two-thirds  of  the  expected  (piantity  of  that 
substance.  Tiiat,  fiu'thcr,  the  ])rothice  of  jiaralline  nuiy  possibly  be  rendered  much  more 
considerable  than  was  stated  by  Mr.  Reece,  through  a  more  judicious  tn^atnient  of  the  resiu- 
i;u3  materials  of  the  tar  than  had  been  proposed  by  that  chemist. 


910  PENCIL  MANUFACTURE. 

"  2.  That  tlio  (listilliition  with  combustion  of  the  peat  in  the  blast  furnaces  must  be  con- 
sidered to  produce  only  the  raw  materials  for  the  subsequent  chemical  operations,  just  as  in 
the  processes  of  wood  or  coal  distillations,  there  are  produced  tar  and  ammonia,  and  acetic 
acid,  which  have  long  been  the  objects  of  manufacture. 

"  3.  That  those  materials,  if  cliarpjcd  with  the  total  cost  of  the  peat  consumed,  the  cost 
of  erecting  and  working  the  furnaces,  the  Ijlast  engines,  and  condensing  apparatus,  and 
proportion  of  management,  would  not  appear  to  be  very  much  more  economicallj  obtained 
from  peat,  than  they  are  now  obtained  from  the  products  of  wood  and  coal  distillation, 
where  they  are  sold  at  very  low  prices,  and,  at  least  as  regards  gas  tar  and  gas  liquor,  in 
most  places  in  Ireland,  have  been  regarded  as  waste  products. 

"  4.  That  the  principal  value  of  the  d.ass  of  products  obtained  from  peat  is  derived 
from  the  cost  of  their  subsequent  purification  and  conversion  into  a  commercial  form,  and 
that  consequently  the  piincipal  advantage  of  a  new  mode  of  obtaining  them  must  be  looked 
for  in  the  more  economical  treatment  of  those  materials. 

"  5.  That  to  this  principle  the  extraction  of  the  paraffine  may  be  an  exception,  it  being 
itself  a  material  new  to  commerce  on  a  large  scale,  and  hence  not  having  its  value  deter- 
mined by  the  comparative  economy  of  preparation  from  sources  of  little  value. 

"  6.  That  tiie  economies  introduced  in  the  treatment  of  the  tarry  and  watery  products  of 
peat  distillation  are  reducible  to  two  (so  far  as  I  have  been  able  to  learn) : — 1 ,  the  separation 
of  the  wood  spirit,  by  means  of  an  improved  distilling  apparatus ;  and  2,  the  utilization  of 
the  waste  gases  from  the  condensing  pipes,  so  as  to  supersede  the  use  of  other  fuel  by  burn- 
ing the  gas  in  jets  under  the  steam  boilets,  tar  and  acetic  acid  stills,  evaporating  pans,  &c. 

"  7.  That  the  former  economy  cannot  be  of  paramount  influence,  as  it  affects  but  one 
stage  of  the  preparation  of  a  single  product,  and  further  miglit  be  applied  in  a  similar  way 
to  lessen  the  cost  of  production  of  wood  spirit  from  any  other  source. 

"  8.  That  the  latter  economy  is  of  the  most  important  character,  and  appears  more  than 
any  other  one  condition  to  influence  the  probable  success  of  the  manufacture  on  the  great 
scale;  that  therefore  the  amount  of  advantage  derived  from  similar  employment  of  gases  in 
iron-smelting  works  will  deserve  careful  comparison,  and  that  it  will  be  necessary  particular- 
ly to  take  into  account  the  difference  of  combustibility  of  gaseous  mixtures  when  very  hot, 
as  when  from  an  iron  furnace,  and  when  quite  cold,  as  from  the  condensing  apparatus  of  a 
peal  l)last  furnace. 

"  9.  That  under  the  circumstances  of  a  manufacture  presenting  so  many  new  and 
complex  processes,  which,  in  analogous  branches  of  industry,  it  is  found  convenient  to  sep- 
arate and  commit  to  different  and  individual  interests,  and  that  its  conditions,  as  to  the 
supply  of  peat,  require  its  establishment  in  localities  of  but  little  industrial  activity,  it  can 
scarcely  be  expected  that  even  as  much  economy  and  advantage  should  be  realized  as  might 
be  expected  after  experience  of  the  same  process  on  a  working  scale  and  with  trained  labor. 

"  10.  That  although  the  excessive  returns  stated  by  the  proposers  of  the  manufacture 
may  not  be  olitained,  it  is  yet  probable  that,  conducted  with  economy  and  the  attention  of 
individual  interests,  the  difficulties  connected  with  so  great  complexity  of  operations  would 
be  overcome,  and  the  maimfacture  l)e  found  in  practice  profitable ;  and  certainly  it  must  be 
regarded  as  of  very  great  interest  and  public  utility  tiiat  a  branch  of  scientific  manufacture 
.should  Ijc  established,  specially  applicable  to  promote  the  industrial  progress  of  Ireland  by 
conferring  a  connnercial  value  on  a  material  which  has  hitherto  been  principally  a  reproach, 
and  bv  affording  employment  of  a  remunerative  and  instructive  character  to  our  laboring 
population." 

PENCIL  MANUFACTURE.  {Orai/nn.%  fabrigw  de,  Fr. ;  Bleixflfte  verfn-lir/iinrf.  Germ.) 
The  word  pencil  is  used  in  two  senses.  It  signifies  either  a  small  hair  biush  employed  by 
painters  in  oil  and  water-colors,  or  a  slender  cylinder  of  black  lead  or  plumbago,  either 
naked  or  enclosed  in  a  wooden  case,  for  drawing  black  lines  upon  paper.  The  last  sort, 
which  is  the  one  to  be  considered  here,  corresponds  nearly  to  the  French  term  crayon, 
though  this  includes  also  pencils  made  of  differently  coloi'cd  earthy  compositions. 

Tlie  best  Ijlack-lead  pencils  of  this  coimtry  are  formed  of  slender  parallclopipeds,  cut 
out  by  a  saw,  from  sound  ])iec('s  of  phnnt):igo,  especially  such  as  have  been  obtained  from 
Borrowdale,  in  Cumbeiland.  These  parallclopipeds  are  generally  enclosed  in  cases  made  of 
cedar  woo<l,  though  of  late  years  they  are  also  used  alone,  under  the  name  of  ever-pointed 
pencils,  in  peculiar  pencil-cases,  piovidcd  with  an  iron  wire  and  screw,  to  protrude  a  minute 
portion  of  the  plumbago  beyond  the  tu!)ular  metallic  case,  in  proportion  a,s  it  is  wanted. 

Pieces  of  jilumbago  sufficiently  large  to  be  thus  employed  are  very  rare,  and  the  supjily 
from  the  Cumberland  mine  can  no  longer  be  iclied  on.  The  mine  has  been  closed  for  some 
years,  but  during  the  past  year  (ISTjO)  a  company  has  lieen  formed  for  again  working  it. 
Manv  attempts  have  been  made  to  utilize  the  smaller  fragments  of  plumbago — as  by  griml- 
ing  tliem,  melting  them  with  suli)liur  or  antimony,  and  the  like ;  but  few  of  these  have  been 
attended  with  any  success. 

The  late  Mr.'  Brockedon  was  long  occujjied  in  seeking  for  some  method  which  might 
enable  liini   lo  employ  the  pure   powder  of  black  lead  without  cementing  it  by  any  sub- 


PENCIL  MANUFACTURE.  911 

staiiee,  which  inevitably  injures  the  quality.  He  endeavored  to  render  the  powder 
colierent  by  submitting  it  to  enormous  pressure;  but  the  different  maeliines  and  apparatus 
lie  at  first  made  use  of  for  this  purpose,  liowever  strongly  they  were  made,  were  broken 
under  the  pressure,  and  his  endeavors  were  thus  unsuccessful,  until  the  happy  idea  sug- 
gested itself  of  operating  in  a  vacuum.  But  it  was  with  extreme  difHculty,  if  not  impossible, 
to  introduce  under  the  receiver  of  an  air  pump  an  apparatus  for  compressing  the  powder  of 
graphite.  Mr.  Brockedon  overcame  this  difficulty  by  an  arrangement  as  simple  as  it  is 
easily  executed  ;  for,  after  having  compacted  the  powder  by  a  moderate  pressure,  and  thus 
reduced  it  to  a  certain  size,  he  enclosed  it  in  very  thin  paper  glued  over  the  whole  suiface. 
He  then  pierced  it  in  one  place  with  a  small  round  hole  permitting  the  escape  of  the  air 
from  within,  when  the  block  thus  prepared  was  placed  under  an  exhausted  receiver,  and  the 
air  having  been  removed,  the  orifice  was  closed  with  a  little  piece  of  paper  (a  small  ad- 
hesive v.-afer  was  usually  employed  for  this  purpose),  and  in  this  state  it  was  found  that  it 
might  be  left  for  24  hours  without  injury.  Being  submitted  to  a  regulated  pressure  once 
more,  the  different  particles  became  agglomerated,  and  an  artificial  block  of  graphite  was 
produced  by  simple  pressure,  as  solid  as  the  specimens  obtained  fiom  the  mine. 

The  artificial  masses  of  plumbago  thus  obtained  owed  much  of  their  character  to  the 
extreme  fineness  to  which  the  plumbago  was  reduced  by  previous  grinding  under  rollers. 
In  this  manner  a  great  deal  of  useless  plumbago  is  worked  up  into  excellent  black-lead  pencils. 
The  different  degrees  of  darkness  in  drawing  pencils  should  be  secured  by  the  selection  of 
specimens  of  plumbago  of  varying  degrees  of  density.  It  is,  however,  commonly  obtained 
by  combining  with  the  plumbago,  sulphur,  or  sulphuret  of  antimony,  and  by  subjecting  the 
I'lamlj  (go  to  the  action  of  heat.  In  the  commoner  kinds  of  pencil  a  very  heterogeneous 
mixture  is  employed ;  indeed,  many  pencils  are  little  more  than  black  chalks. 

Tiie  description  of  the  pencil  works  at  Keswick,  given  in  Chambers' Journal,  in  1S48.  is 
so  graphic  and  correct  that  we  do  not  hesitate  to  transfer  much  of  it  to  these  pages. 

The  factory  consists  of  a  house  of  several  stories,  in  the  lower  of  which  is  a  huge  water- 
wheel  turned  by  the  Greta,  outside  being  the  cedar  wood  ready  for  use.  The  quantity  of 
cedar  consumed  annually  by  the  establishment  is  four  thousand  cubic  feet.  These  cedar  logs 
are  sawed  into  planks,  and  then  a  circular  saw  cuts  the  planks  into  smaller  pieces,  prepara- 
tory for  the  grooving  engine  ;  this  grooving  engine  consists  of  two  revolving  saws,  going  at 
inconceivable  speed  ;  one  saw  cutting  the  slips  of  wood  into  narrow  square  rods,  and  the 
other  making  a  groove  along,  the  rod  and  cutting  to  size  at  the  same  time  ;  adjoining  the 
grooving  apparatus  is  a  circular  saw,  cutting  slips  of  cedar  as  covers  to  the  grooved  lengths. 

The  plumbago,  if  good,  needs  no  refining;  it  is  used  precisely  in  the  condition  in  which 
it  leaves  tlie  mine.  To  ascertain  its  qualities  each  piece  is  scraped  with  the  edge  of  a  knile, 
besides  being  otherwise  tested  ;  and  in  proportion  as  there  is  no  gritty  particles  in  it,  so  is 
it  the  more  valuable.  Some  pieces  are  harder,  some  a  little  darker  in  color,  than  others ; 
and  according  to  these  peculiarities,  they  are  employed  for  pencils  of  various  hardness  and 
shades.  The  whole  knack  of  pencil-making  seems  to  depend  on  the  detection  of  these  nice- 
ties in  the  l)its  of  lead,  and  also,  of  course,  in  their  honest  adaptation  to  the  varieties  which 
ar.?  dealt  out  to  the  public.  Plumbago  of  an  impure  kind  is  ground  to  powder ;  the  grit, 
as  far  as  possible,  separated  from  it,  and  the  cleansed  material,  mingled  with  a  cohesive 
liquid,  is  dried  and  pressed  into  hard  lumps  for  use.  This  process,  however,  is  applied 
principally,  if  not  exclusively,  to  the  plumbago  imported  from  India,  and  only  in  leference 
to  pencils  of  the  commonest  soit.  Pencils  made  with  such  stuff  are  valueless  to  artists;  for 
independently  of  their  want,  of  tone,  they  are  never  altogether  free  from  grit.  The  only 
good  pencil  is  one  made  from  geinune  Borrowdale  lead,  pure  from  the  mine,  and  adapted 
by  a  skilful  manufacturer  to  its  assigned  purpose.  The  mode  of  preparing  the  pieces  of 
good  plumbago  for  the  pencil  is  very  simple.  All  the  bits,  with  their  surface  merely  scrap- 
el,  are  glued  to  a  board,  in  order  to  fix  them  in  a  position  for  being  sawn.  When  so  fixed 
t!iey  are  brought  under  the  action  of  a  .saw,  which  divides  them  into  thin  slices  or  scantlings. 
Tliese  slices  are  now  handed  to  the  fitter.  This  is  an  operative  who,  with  a  lot  of  grooved 
rods  before  him,  sticks  slices  of  the  lead  into  grooves,  snapping  off  each  slice  level  with  the 
surface,  so  as  just  to  leave  the  groove  properly  filled.  In  the  making  of  a  single  pencil, 
fierhaps  as  many  as  three  or  four  slice  lengths  are  recpiired  ;  but  however  many,  each  slice 
is  fitted  exactly  endlong  with  another,  so  as  to  leave  no  intervals.  The  rods  being  thus 
filled,  are  cariied  to  the  fastener-up.  This  person  glues  the  cedar  covers  or  slips  over  the 
fille  1  rods  ;  and  having  got  a  certain  number  arranged  alongside  of  each  other,  he  fixes  them 
tightly  together,  and  lays  them  aside  to  dry.  When  dried  they  are  ready  for  being  rotnided. 
The  rounding  is  done  i)y  an  apparatus  fixed  to  a  trench — a  thing  of  revolving  planes  or 
turning  tools.  Into  this  engine,  rods  are  put  one  after  another,  and  out  they  come  as  fast 
as  the  eye  can  follow  them,  rounded  to  a  perfect  nicety.  By  this  simple  and  efficient 
machine  a  man  will  roimd  from  six  hundied  to  eight  hundred  dozens  of  pencils  in  a  <lay. 
After  being  roimded  they  get  a  smoothing  with  a  [)lane,  and  then  they  are  polished  bv 
being  rubbed  with  a  peculiar  kind  of  fish-skin  ;  this  latter  o|ieration  l)eing  i)erfornied  liy 
girls.     Being  [)olisheil,  the  next  step  is  to  cut  the  rods  into  length.-*  with  a  civcular  saw. 


912  PERFUMERY,  ART  OF. 

after  which  the  Iciijrtns  are  respectively  smoothed  at  the  ends.  Nothing  now  remains  but 
to  stamp  the  name  of  the  makei-,  with  the  letters  significant  of  tlieir  C|uality.  The  stamiiing 
engine  is  as  ingenious  a  piece  of  machinery  as  is  in  the  establishment.  Fed  into  it,  the 
pencils  are  stamped  in  less  than  an  instant  of  time.  A  girl  will  with  this  apparatus  stamp 
two  hundred  pencils  i)er  minute.  Gathered  from  a  box  below  into  which  the  pencils  fall, 
they  are  carried  away  to  be  tied  in  bundles. 

PERFUMERY,  ART  OV,  {Farfianerir,  Fr.  ;  Wohlriechende-Kunst,  Germ. ;)  consists 
in  the  extraction  of  the  odors  of  plant.s,  isolating  them,  A  and  B — and  in  combining  them 
with  inodorous  materials ;  such  as  grease,  C,  spirit,  D,  starch,  E,  soaps,  F ;  also  in  the 
manufacture  of  cosmetics,  G,  dentifrices,  pastes,  tinctures,  II,  incense  and  pastils,  I,  po- 
mades, oils,  and  other  toilet  appendages,  K,  hair  washes,  hair  dyes,  depilatories,  L. 

(A  and  B.)  There  are  three  distinct  methods  of  procuring  the  odors  of  plants.  1st.  By 
DiSTiLL.iTioN.  If  cloves,  cinnamoH  bark,  or  the  odorous  leaves  of  plants  or  wood,  be  dis- 
tilled, the  fragrant  principle  contained  therein  rises  with  the  steam,  which,  being  condens- 
ed, the  otto,  or  essential  oil,  will  be  found  floating  upon  the  water.  This  process  has 
already  been  described  (see  Distili..\tion,  Ottos)  ;  but  can  only  be  beneficially  applied  by 
the  perfumer  to  the  procuring  of  certain  odors :  from  woods,  such  as  santal  and  cedar  ;  from 
leaves,  such  as  patchouli  and  bay  leaves ;  from  various  grasses,  such  as  the  lemon  grass  and 
citronella  of  Ceylon  ;  from  the  several  seeds,  such  as  carraway  and  nutmeg ;  and  but  to  two 
or  three  flowers,  such  as  orange  blossom,  rose,  and  lavender.  The  various  fragrant  woods, 
seeds,  and  leaves  are,  however,  almost  as  numerous  as  there  are  plants  upon  the  earth,  and 
as  a  consequence,  the  perfumer  can  have  as  great  a  variety  of  ottos  by  distilling  for  them. 

(C.)  Sd.  Enkleirage.  When  it  is  desired  to  obtain  the  odors  of  flowers,  such  as  those 
of  jasmin,  acacia,  violet,  tuberose,  jonquil,  and  numerous  others,  the  process  of  distillation 
is  inapplicable  and  useless,  and  that  peculiar  but  simple  method,  termed  "  Enfleurage," 
must  be  adopted.  This  plan  is  founded  on  the  fact  that  greasy  bodies  readily  absorb 
odorous  particles,  and  will  as  freely  part  with  them  if  in  contact  with  pure  alcohol.  The 
operation  of  enfleurage  is  thus  conducted  at  Messrs.  Picsse  and  Lubiu's  laboratory  of  flow- 
ers, near  Nice,  in  Sardinia  (now  France,  1860). 

Purijication  of  the  grease.  A  corps,  or  body  grease,  is  first  produced  by  melting  to- 
gether equal  parts  of  deer  or  beef  suet  (the  former  is  preferred),  mutton  suet,  and  lard  ;  it 
is  then  clarified  thus: — take  1  cwt.  of  grease,  divide  it  into  portions  of  aljout  2  lbs.,  place 
one  of  these  in  a  mortar  and  well  pound  it ;  when  it  is  well  crushed  wa.-;h  it  with  water 
repeatedly,  so  long,  in  fact,  until  the  water  is  as  clear,  after  withdrawing  the  grease,  as 
before  it  was  put  in.  The  several  lots  of  grease  prepared  m  this  way  have  now  to  be  melt- 
ed over  a  slow  fire,  adding  thereto  about  3  ounces  of  crystallized  alum  in  powder  and  a 
handful  of  sea  salt  (common  salt) ;  now  let  the  grease  boil,  but  allow  it  to  bubble  for  a  few 
seconds  only ;  then  strain  the  grease  through  a  fine  linen  into  a  deep  pan  and  allow  it  to 
stand  to  clear  itself  from  impurities  for  about  two  or  three  hours.  The  cleargrcase  is  then 
again  put  into  the  melting  vessel  over  a  charcoal  fire,  adding  thereto  about  three  or  four 
quarts  of  rose  water  and  half  a  pound  of  powdered  gum  benzoin  ;  it  is  then  allowed  to  boil 
gently,  and  all  scum  that  rises  carefully  removed  until  it  ceases  to  be  produced.  Finally, 
the  grease  is  poured  into  deep  pans  to  cool ;  when  solid  it  is  removed  off  the  sedimentary 
water,  and  again  being  liquefied  may  be  placed  in  store  vessels  for  future  use,  where  it  may 
be  kept  for  an  indefinite  period  without  change  or  becoming  rancid.  This  jjurification  of 
the  grease  gives  employment  to  those  engaged  in  the  laboratory  at  a  season  when  the  flow- 
ers are  not  in  bloom.  M.  Herman,  of  Cannes,  and  M.  Pilar,  of  Grasse,  prepare  in  this  way 
during  winter,  together,  one  hundred  and  twenty  thousand  pounda  of  perfectly  inodorous 
grease. 

The  growers  of  the  flowers,  of  course,  pay  due  attention  to  their  cultivation,  so  as  to 
produce  an  abundance  of  blossom  in  due  season.  Although  it  is  not  necessary  that  the 
flower  farmer  should  be  a  perfumery  factor,  it  is  useful  that  the  latter  should  have  some 
knowledge  of  the  former  avocation,  so  as  to  be  prepared  for  each  harvest  of  floweis  as  they 
succeed  each  other ;  and  when  it  is  practicable  to  unite  the  occupations,  better  pecuniary 
results  follow.  At  Cannes  and  Grasse,  iu  France,  wliich  arc  separated  from  the  frontier 
of  Sardinia  only  by  tlie  river  Var,  and  are  distant  from  Nice  about  30  miles,  the  entire 
population  is  more  or  less  interested  in  this  particular  manufacture.  The  various  flowers 
there  cultivated  do  not  come  into  blossom  at  one  time,  but  in  succession  ;  so  that  there  is 
ample  time  to  attLiid  to  each  in  turn. 

The  enfleurage  process  is  thus  conducted : — Square 
frames  varying  in  size  from  20  to  SO  inches  are  made,  in 
the  centre  of  which  is  fixed  a  piece  of  stout  glass  as  in 
fiff.  555.  Each  fraiue  is  1  i  inch  deep  from  the  top  edge  to 
the  glass,  so  that  if  two  frames  be  placed  together  face  to 
face,  there  is,  as  it  were,  a  glass  Ijox  with  a  wooden  frame, 
having  a  depth  of  3  inches  between  each  glass.  This 
affords  ample  room  for  the  blosjoms  to  lie  between  them  without  being  crushed.     In  due 


PnOSPHORUS,  AMOEPnOUS. 


913 


season,  that  is,  when  the  flowers  begin  to  bloom,  about  half  a  pound  of  the  purified  grease 
is  spread  upon  each  side  of  the  glass  with  a  spatula  or  pallet  knife.  The  gathered  blossoms 
are  then  hand-spriukled  or  broad-cast  over  the  grease  in  one  frame,  and  another  fiame  is 
put  over  it  so  as  to  enclose  the  flowers.  This  operation  is  repeated  as  many  times  as  there 
are  flowers  to  spread  over  each.  These  frames  are  termed  c/idst'e,  which  literally  means 
'■  Sash."  Now,  we  are  all  familiar  with  window 
sashes — that  is,  a  glass  with  a  frame  round  it — and 
such  is  in  truth  the  chasse  used  in  the  enflcuvage 
process.  Doubtless  our  window  "sash"  is  derived 
from  the  French.  Chasse  may  also  be  rendered  in 
English,  "a  frame."  Enfleurage,  then,  is  conducted 
upon  a  glass  frame  or  sash.  About  every  other  day, 
or  every  third  day,  the  spent  flowers  being  thrown 
away,  fresh  ones  are  placed  upon  the  grease  ;  this 
manipulation  being  repeated  so  long  as  the  plants 
yield  blossoms,  a  time  that  varies  from  one  to  two 
months.  After  every  addition  of  flowers,  it  will  be 
observed  that  the  grease  increases  in  the  fragrance 
of  tlie  flower  with  which  it  was  sprinkled,  and  this 
continues  till  the  enfleurage  is  complete,  at  which 
time  the  grease,  now  called  "Pomade,"  is  scraped 
off  the  sashes,  put  into  vessels,  then  placed  in  hot 
water — a  water  bath.  By  so  doing  the  pomade  is 
liciuefied,  but  is  not  made  hot  enough  to  destroy  its 
odor.  By  this  treatment  various  extraneous  mat- 
ters, such  as  a  few  anthers  of  flowers,  a  stray  bee, 
some  pistils,  or  loose  part  of  the  corolla,  a  wayward 
butterfly  and  moth,  and  such  similar  things,  are 
removed,  by  pouring  the  clear  pomade  into  the  canisters  through  fine  linen.  When  the 
pomade  is  cold  enough  it  sets  in  these  vessels,  and  is  then  fit  for  exportation  or  for  ulterior 
uses.     Fir/.  556  represents  a  pile  of  chasse. 

3.  Maceration.  In  some  few  instances  better  results  are  obtained  by  adopting  the 
process  of  maceration,  which  consists  in  infusing  the  fresh  flowers  in  liquefied  grease.  For 
this  purpose,  the  purified  grease  is  placed  in  a  hot-water  bath,  that  is,  the  vessel  containing 
the  grease  is  set  in  another  of  a  larger  size,  in  which  water  is  kept  warmed  over  a  stove. 
In  tlie  French  laboratories,  this  apparatus  is  known  as  the  bam  mark,  salt  being  put  into 
the  water  to  increase  its  boiling  point.  Every  time  fresh  flowers  are  gathered  the  spent 
ones  arc  strained  away,  and  the  fresh  flowers  put  into  the  partially  scented  grease.  In  a 
few  instances  it  is  found  advantageous  to  begin  perfuming  the  grease  by  maceration,  and  to 
finally  finish  it  by  enfleurage  ;  this  is  especially  the  case  with  violet  pomade. 

After  the  maceration  is  completed,  that  is,  when  there  are  no  more  flowers  to  be  had, 
the  grease  must  be  kept  steadily  at  a  uniform  degree  of  liquefaction,  in  order  that  friable 
portions  of  the  flowers,  &c.,  may  subside,  so  that  the  fair  pomade  can  be  separated  there- 
from pure  and  unsullied.  Oils  are  scented  by  enfleurage  and  maceration  processes  by  a 
slight  difference  of  mechanical  arrangement.  Thus,  the  sash  in  lieu  of  glass  contains  a  wire 
gauze,  like  a  coarse  wire  blind  (cAa.s-w  f?2/er) ;  upon  this  gauze  is  laid  a  thick  piece  of 
fustian-like  cotton  fa))ric  (mollclon  da  colon),  which  has  previously  been  steeped  in  the 
purest  olive  oil.  Upon  each  molleton  laid  in  the  s:ish  frame  the  flowers  are  sprinkled  in  the 
same  way  as  if  it  were  for  pomade,  and  the  flowers  are  changed  as  often  as  possible.  When 
the  plants  cease  to  bloom,  each  molleton  is  wrapped  in  a  strong  cord  net,  and  placed  in  a 
hydraulic  or  other  press,  for  the  purpose  of  squeezing  the  fragrant  oil  away  from  it.  Oils 
of  tuberose,  rose,  violet,  jonquil,  acacia,  and  orange  are  thus  prepared. 

According  to  the  length  of  time  the  enfleurage  process  occupies,  and  the  quantity  of 
flowers  employed  over  the  same  grease,  the  pomade  or  oil  bears  numbers  respectively. 
Thus  we  have  No  12  pomade,  No  18  oil.  No  24  pomade,  indicating  their  relative  strength 
of  fragrance,  that  is,  the  quantity  of  flowers  employed  iu  their  manufacture. 

PERXAMBUCO  WOOD.  See  Brazil  Wood. 

PETWOUTII  MARBLE.  A  shelly  limestone,  occurring  in  the  Wealden  strata,  in  the 
neighborhood  of  Petworth,  in  Sussex.     11.  W.  B. 

PHOSPHORUS,  amorphous  ;  or  Reu  Pnospiiours.  If  a  stick  of  phosphorus  be  put 
into  a  hermetically  closed  tube  and  exjiosed  to  the  action  of  the  .spectrum,  one  end  will 
b'ccome  ichilc  and  the  other  red.  It  may  be  prepared  also  by  exposing  phosphorus  for  a 
long  time  in  an  atmosphere  (piite  free  of  oxygen  or  moisture,  to  a  temperature  of  470"  F. 
At  this  tcmperatuic  the  phosphorus  fuses;  it  remains  for  some  time  colorless,  and  then 
gradually  becomes  red  and  opaque.  Amorjihous  phosphorus  was  investigated  by  Dr. 
Schrotter,  of  Vienna.  The  apparatus  for  making  it  consists  ol"  a  double  iron  pan  ;  the  inter- 
mediate space  between  the  two  contains  a  metallic  bath  of  an  alloy  of  (in  and  lead  ;  with  a 
Vol.  III.— 58 


914 


PHOTOGEN". 


cast-iron  cover  to  the  inner  vessel,  fitted  to  the  top  end  by  means  of  a  screw,  and  fa^tLned 
to  the  outer  vessel  by  screw  pins.  In  the  interior  iron  vessel  a  glass  vessel  is  fitted,  in 
which  the  phosphorus  to  be  operated  upon  is  placed.  From  this  inner  vessel  a  tube  passes, 
and  is  dipped  into  water  to  serve  as  a  safety  valve  A  spirit  lamp  is  applied  under  that 
j)ipo  if  necessary,  to  prevent  its  being  clogged  with  phosphorus.  The  phosphorus  to  be  con- 
verted is  first  of  all  melted  and  then  cooled  under  water,  and  dried  as  much  as  possible. 
A  fire  is  now  made  under  the  other  vessel,  and  the  temperature  raised  to  such  a  degree  as 
to  drive  off  the  air,  &;c.  The  temperature  has  to  be  gradually  raised,  until  bubbles  escape 
at  the  end  of  the  pipe,  which  take  fire  as  they  enter  the  air,  and  the  heat  may  soon  rise  in 
the  bath  till  it  be  470  F.  This  temperature  must  be  maintained  for  a  certain  time  to  be 
determined  by  experience ;  the  apparatus  may  then  be  allowed  to  cool.  The  converted 
phosphorus  is  dilhcult  to  detach  from  the  glass.  It  is  to  be  levigated  under  water,  and  then 
drained  in  a  bag.  The  phosphorus  when  moist  should  be  spread  thinly  on  separate  shallow 
trays  of  sheet  iron  or  lead,  so  placed  alongside  each  other  as  to  receive  the  heat  of  steam, 
and  lastly  of  chloride  of  calcium  or  of  sand,  till  the  phosphorus  having  been  fiequently  stir- 
red, shows  no  more  luminous  vapor.  The  operator  .should  have  water  at  hand  to  quench 
any  fire  that  might  arise.  It  is  then  to  tje  washed  till  the  water  shows  no  trace  of  acid. 
Should  the  resulting  phosphorus  contain  some  of  the  unconverted  article,  this  may  be 
removed  by  bisulphuret  of  carI)on.  Thus,  heat  alone  effects  the  transmutation.  Il  is 
identical  in  composition  with  ordinary  phosjihorus,  and  may  be  reconverted  into  it  without 
loss  of  weight,  and  that  merely  by  change  of  temperature.  This  substance  remains  unalter- 
ed in  the  atmosphere,  is  insoluble  in  sulphuret  of  carbon,  in  alcohol,  ether,  and  naphtha. 
It  re(iuires  a  heat  of  2()0°  C.  to  restore  it  to  the  ordinary  state,  and  it  is  only  at  that  heat , 
that  it  begins  to  take  fire  in  the  open  air.  It  is  not  luminous  in  the  dark  at  any  ordinary 
temperature.  When  perfectly  dry,  amorphous  phosphorus  is  a  scarlet  or  carmine  powder, 
which  becomes  darker  when  heated.  On  the  large  scale  it  is  prepared  in  dark  masses  of 
a  red  or  dark  brown  color.  The  great  advantages  of  this  singular  condition  of  phosphorus 
are,  that  it  docs  not  appear  to  affect  those  persons  v.ho  are  employed  in  the  manufactuie 
of  lucifer  matches  with  the  loathsome  disease  which  the  use  of  tlie  ordinary  phosphorus 
produces.     See  Luciker  Matches. 

PI10T0(>EX.  Syn.  Pctraffine  Oil.  A  term  which  has  recently  found  its  way  into 
commerce,  to  designate  certain  oils  or  na])hthas  for  illuminating  purposes.  It  is  generally 
prepared  from  shales,  brown  coals,  or  canncls.  Boghead  coal,  and  the  numerous  varieties 
of  inflammalile  shales  whicli  more  or  less  resemble  it,  are  specially  adapted  for  the  prcpaiii- 
tion  of  photogen.  The  chief  physical  difference  between  photogen  and  ordinary  coal  oils 
of  the  same  boiling  point,  is  the  specific  gravity,  which  with  the  former  varies  from  0"820 
to  0-830,  whereas  common  co-al  naphtha  never  has  a  less  density  than  0850°.  It  is  true 
that  photogen  may  be  obtained  of  as  high  a  density  as  0'900,  but  then  it  will  be  of  an  ex- 
cessively high  boiling  point,  and,  in  all  probability,  saturated  with  paraffine. 

Tiie  light  oil  known  as  photogen  may  be  obtained  from  common  bituminous  coals  by 
distilling  them  at  a  lower  temperature  than  is  employed  in  gas  works.  To  obtain  the  maxi- 
mum amount  of  photogen  from  coal,  the  temperature  should  not  be  much  above  700'  C. 

Preparation. — The  coals  broken  in  small  pieces,  the  smaller  the  better,  are  to  be  heat- 
ed in  vertical  or  hoiizontal  iron  retorts,  the  tar  being  received  through  a  very  wide  worm 
into  large  tanks.  Some  manufacturers  use  vertical,  and  others  horizontal  retorts  ;  it  is  also 
common  to  distil  the  coals  by  tl>c  heat  produced  by  their  own  combustion.  If  the  latter 
process  be  employed,  the  arrangements  for  condensing  the  product  must  be  vciy  perfect, 
or  great  loss  will  lie  sustained,  owing  to  the  air  which  supports  the  combustion  carrying 
away  a  considerable  quantity  of  the  hydrocarbons.  This  power  of  air  to  saturate  itself  with 
vapors,  is  of  gieat  importance  in  the  economy  of  all  processes  where  the  distillation  of  one 
portion  of  substance  is  carried  on  by  the  heat  evolved  by  the  combustion  of  another.  It  is  not 
uncommon  in  practice,  where  the  cylinders  are  horizontal,  to  place  the  coal  or  other  matters 
to  be  distilled  in  semi-cylindrical  trays,  which  are  capable  of  being  inserted  into  the  retorts, 
and  also  of  being  removed  to  make  way  for  another  charge  at  the  completion  of  the  operation. 

The  tar  obtained  i)y  any  of  the  above  processes  is  to  be  redistilled  ;  the  lighter  portions 
form  (when  purified  by  means  of  sulphuric  acid  and  alkalies)  the  fluid  known  in  commerce 
as  "Boghead  naphtha."  See  Naphtha,  BociiKAn.  In  Germany  and  some  other  places,  it 
is  usual  to  divide  the  distillate  from  the  tar  into  two  portions,  one  being  for  the  preparation 
of  [)hotogen,  and  the  other  for  "solar  oil."  This  division  is  made  as  the  fluid  runs  from  the 
still ;  the  more  volatile  constituting  the  photogen,  and  the  less  the  solar  oil. 

The  process  of  purification  is  the  same  in  both  cases,  namely,  alternate  treatments  with 
concentrated  sulphuric  acid  to  remove  the  highly  colored  and  odorous  constituents  of  the 
crude  distillate,  and  washing  with  an  alkali  to  remove  carbolic  acid  and  its  congeners;  also 
that  portion  of  sulphuric  acid  which  remains  suspended  in  the  naphtha,  and  the  sulphurous 
acid  produced  by  the  decomposition  of  a  i)ortion  of  the  sulphuric  acid  by  the  carbon  of 
certain  easily  decomposed  organic  matters  in  the  crude  distillate.  This  decomposition  of 
the  sulphuric  acid  happens  thus  : — 

2S0'IIO  +  C  =  2.-;O^+ 2110  +  00'. 


PHOTOGRAPHIC  ENGRAVING. 


915 


There  is  another  advantage  in  the  treatment  of  the  fluid  by  alkalies,  inasmuch  as  some 
sulphide  of  hydrogen,  and  piobably  olhur  fa>tid  sulphur  compounds,  is  decomposed  and  the 
resulting  products  removed. 

In  preparing  photogen  from  any  of  the  sources  enumerated,  much  must  be  left  to  the 
discretion  of  the  manufacturer  both  as  regards  the  apparatus  and  the  chemical  processes. 
In  some  instances  the  solar  oil  and  photogen  are  with  advantage  prepared  separately,  but 
in  this  country  it  is  more  usual  to  mix  the  heavy  and  light  oils  together  so  as  to  produce  a 
fluid  of  medium  density  and  volatility.  It  must  be  remembered  that  while  the  moie  vola- 
tile hydiocaibons  confer  extreme  inflammability  and  fluidity,  they  are  at  the  same  time 
more  odorous  than  the  less  volatile  portion  of  the  distillate,  which  is  the  true  paraffine  oil. 

The  more  odorous  impurities  in  photogen  appear  to  be  easily  susceptible  of  oxidation. 
This  is  evident  from  the  facility  with  which  foully  smelling  photogen  loses  its  olfensive  odor 
in  co:Uact  with  bichromate  or  manganate  of  potash,  or  even  animal  charcoal.  Their  ex- 
PQBurL^  to  air  even  gi-eat!y  improves  the  odor,  and  a  recently  disti.led  photogen,  which  is 
very  unpleasant,  becomes  comparatively  sweet  if  kept  in  tanks  or  barrels  ibr  a  few  days. 
The  same  thing  happens  with  many  essential  oils,  such  as  those  of  peppermint,  cloves,  &c. 
Tae  presence  of  sulphurous  acid  in  photogen  may  be  instantly  detected  by  shaking  a  little 
in  a  test  tube  with  a  few  drops  of  a  very  weak  solution  of  bichromate  of  potash;  if  sulphu- 
rous acid  be  present  a  portion  of  the  chromic  acid  will  be  reduced  to  green  oxide,  which 
will  instantly  betray  the  presence  of  the  reducing  agent  alluded  to. 

Piiotogen  often  shows  the  phenomenon  of  dichroisra,  but  the  more  it  is  purified  by  acids 
the  more  feebly  is  the  coloration  by  reflected  light  observed,  and  if  the  less  volatile  portion 
of  the  distillate  be  rejected,  the  property  alluded  to  will  not  be  perceived. 

In  distilling  the  heavy  oils  or  tars  produced  by  distilling  Boghead  coal  or  other  photo- 
gen-yielding  substances,  it  is  particularly  to  be  observed  that  the  worms  or  other  tubes  pro- 
ceeding from  the  stills,  if  of  too  small  diameter,  are  liable  to  become  choked  up  with 
paraffine;  this,  unobserved,  might  lead  to  serious  results.  It  is  very  convenient  to  have  a 
steam  pipe  inserted  into  the  worm  tubes  or  condensing  tanks,  to  enable  the  water  to  be 
heated  to  such  a  point  as  to  melt  any  solid  matters  in  the  worms,  and  allow  them  to  be 
waslied  into  the  recipient  by  the  fluids  distilling  over. 

None  of  the  cannel  or  bituminous  coal,  shales,  or  other  substances  used  for  yielding 
burning  fluid  by  distillation,  gives  distillates  of  such  purity  and  freedom  from  odor  as 
Rangoon  tar.  The  more  volatile  portion  of  the  distillate  fiom  the  latter  has  obtained  in 
commerce  the  absurd  name  of  Sherwoodole  ;  it  is  used  instead  of  coal  benzole,  for  removing 
gi-case,  &c.  The  parafline  obtained  from  Rangoon  tar  has  a  greater  value  for  commercial 
purposes  than  that  from  Boghead  coal,  inasmuch  as  it  has  a  higher  melting  point,  which 
renders  it  better  adapted  for  candles.  Tlie  following  are  the  melting  points  of  various 
samples  of  parafline : — 


McUins  point. 
114'  Fahr. 
108°     " 


Boghead  coal  paraffine 

"  "         another  specimen  -         -         -         - 

The  last,  after  being  distilled 108°     " 

Turf  paraffine ]  16'     " 

Bituminous  coal  paraffine,  prepared  by  Atwood's  process  -  -  110"  " 
Rangoon  tar  paraffine  -.---...  140°  " 
It  is  curious  to  observe  the  effi?ct  of  light  upon  photogen.  Some  samples  of  extremely 
dark  color,  when  exposed  to  its  influence  for  a  few  days,  become  as  completely  bleached  as 
animal  oils  would  under  these  circumstances.  At  the  same  time,  as  we  have  before  hinted, 
the  odor  becomes  much  improved.  A  photogen  of  good  quality  has  by  no  means  a  re- 
pulsive odor,  but  if  much  of  the  more  volatile  constituents  be  present,  it  is  impossible  to 
avoid  its  being  disagreeable  if  spilled  about.  The  less  volatile  hydiocarbons  have  compara- 
tively little  odor.  It  should  not  be  too  inflammable,  that  is  to  say,  it  must  not  take  fire  on 
the  approach  of  a  light.  If  it  does,  it  is  owing  to  the  more  volatile  portion  not  having  been 
sufficicntlv  removed. — C.  G.  W. 

PHOTOGRAPHIC  ENGRAVING.  The  fir.st  who  appears  to  have  had  any  idea  of 
heliograpluc  engraving  was  Nicephore  Nicpcc.  According  to  M.  Aime  Girai-d  the  first 
proof  taken  by  him  by  moans  of  this  process  bears  date  1827,  some  dozen  years  before  the 
publication  of  Mr.  Talbot's  PAo/oye?(ic  ^roct'-s.vr.s'.  This  process,  wliich  is  now  almost  for- 
gotten. Wits  very  simple  ;  it  consisted  in  spreading  a  thin  layer  of  bitumen  of  Jiidea  upon  a 
copper  or  pewter  plate,  which  was  then  placed  in  the  camera  obseur.i,  where  it  was  allowed 
to  remain  some  hours,  until  it  had  received  the  im|)ression  of  the  external  objects  towards 
which  the  lens  had  been  directed.  On  withdrawing  the  plate  it  was  submitted  to  tiie  action 
of  the  essence  of  lavender,  which  dissolved  the  portions  of  the  bitumen  not  acted  upon  l)y 
the  light,  leaving  the  metal  bare,  while  the  remaining  bitumen  reproduced  the  design. 
Passing  tlijc  plate  afterwards  through  an  acid  solution  it  was  found  that  it  had  eaten  hollows 
in  the  metallic  plate,  while  the  other  parts  were  preserved  by  the  protecdng  varnish.  Such 
was  the  process  that  M.  Niepce  revealed  to  Daguerre  when  he  entered  into  a  partnership 


91 T) 


PHOTOGRAPHIC  EXGRAYIXG. 


with  him.     Xifepco  died  in  1833,  after  struggling  twenty  year.a,  during  wliifh  lie  spent  Lis 
time  and  money  in  endeavoring  to  perfect  his  discovery,  poor  and  uln.ost  uul^nowu. 

Six  years  later,  that  is  in  1839,  M.  Daguerre  made  his  discovery  public.  In  the  mean 
time  he  had  considerably  improved  on  Niepce's  process  ;  but  the  introduction  of  the  Calo- 
type  led  to  the  abandonment  of  the  process  for  some  years. 

The  next  process  to  which  we  shall  refer  is  that  of  M.  Fizeau.  He  took  a  daguerreotype 
plate  and  submitted  it  to  the  action  of  a  mixture  of  nitric,  nitrous,  and  hydrocliloric  acids, 
which  did  not  affect  the  whites  of  the  picture  but  attacked  the  blacks  with  a  resulting  forma- 
tion of  adherent  chloride  of  silver,  which  speedily  arrested  the  action  of  the  acid.  This  he 
removed  by  a  solution  of  ammonia,  and  the  action  of  the  acid  was  continued.  This  process 
he  continued  until  a  finely  engraved  plate  was  the  result ;  but  the  lines  of  this  plate  M-ere 
not  deep  enough  to  allow  of  prints  being  taken  from  it ;  and  to  remedy  this,  he  covered  the 
plate  with  some  drying  oil,  and  then,  wiping  it  from  the  surface,  left  it  to  dry  in  the  hollows. 
He  afterwards  submitted  the  plate  to  an  electro-chemical  process  which  covered  the  raised 
parts  with  gold,  leaving  the  hollows  in  which  the  varnish  remained  untouched.  On  the 
completion  of  the  gilding  this  varnish  was  removed  by  means  of  cau.stic  potash,  and  the 
surface  of  the  plate  covered  with  c/rahts  de  grarurc,  producing  what  is  technically  termed 
an  aquatint  ground,  and  the  deepening  of  the  lines  was  proceeded  with  by  means  of  the 
acid.  The'Daguerreotype  plate  was  by  these  means  converted  into  an  engraved  plate,  but 
as  it  was  silver  it  would  have  worn  out  very  soon  ;  to  obviate  which  an  impression  was 
taken  on  copper  by  an  electro-chemical  process,  which  could  of  course  be  renewed  when  it 
showed  signs  of  wear. 

M.  Claudet  and  Mr.  Grove  both  produced  some  very  beautiful  engravings  on  the 
Daguerreotype  plate,  but  as  these  processes  have  proved  rather  curious  than  useful,  they 
need  not  be  described. 

On  the  29th  of  Oct.,  1852,  Mr.  Fox  Talbot  patented  a  process,  which  was  similar  to  the 
Pkotocalvaxographic  process  previously  used  by  MM.  Pretsch  and  Poitevin,  as  regards 
the  sub-stance  first  used,  viz.,  a  mixture  of  bichromate  of  potash  and  gelatine ;  but  the 
remaining  portion  of  the  process  was  conducted  on  the  same  principle,  though  in  a  different 
manner,  to  that  of  M.  Fizeau. 

Mr.  Mungo  Ponton  discovered  the  use  of  the  bichromate  of  potash  as  a  photographic 
agent,  and  Mr.  Robert  Hunt  subsequently  published  a  process,  called  the  "  Chromotype." 
In  both  these  processes  the  peculiar  property  of  the  chromic  acid  liberated  under  the  action 
of  sunshine,  to  combine  with  organic  matter,  was  pointed  out.  MM.  Pretsch,  Poitevin,  and 
Talbot  only  availed  themselves  of  this  previous  discovery,  and  in  each  instance  gelatine 
was  rendered  insoluble  by  the  decomposition  of  the  bichromate  of  potash  under  the  influence 
of  aclinic  power.  By  dissolving  off  the  still  soluble  portions  of  the  gelatine,  cither  metal 
could  be  precipitated  by  the  voltaic  battery,  or  an  etching  produced. 

In  1853  M.  Niepce  de  St.  Victor,  the  nephew  of  Xicephore  Niepce,  took  up  his  uncle's 
plan,  and  with  the  assistance  of  M.  Lemaitre,  who  had  also  assisted  his  uncle,  endeavored 
to  perfect  it ;  but  though  he  modified  and  improved  it,  his  success  was  not  very  great ;  it 
was  always  found  necessary  to  have  the  assistance  of  an  engraver  to  complete  the  plate. 

After  this  many  t)thers,  among  whom  may  be  enumerated  MM.  Lerebours,  Lemercier, 
Barreswil,  Davannc,  and  finally  Poitevin,  endeavored  to  obtain  a  design  by  similar  means 
on  stone.  The  last  appears  to  have  succeeded.  His  method  is  based  on  the  chemical  re- 
action of  light  on  a  mixture  of  gelatine  and  bichromate  of  potash,  as  above.  This  mixture, 
which  when  made  is  perfectly  soluble  in  water,  becomes  insoluble  after  exposure  to  the 
light.  His  mode  of  proceeding  is  as  follows : — lie  spreads  the  mixture  on  the  stone,  and 
after  drying  lays  the  negative  upon  it  and  exposes  it  to  the  light.  After  a  suitable  exposure 
the  negative  is  removed,  and  the  portions  not  acted  upon  Ijy  the  light  are  washed  away 
with  water,  and  the  design  remains  with  the  property  of  taking  the  ink  liko  an  ordinary 
lithographic  crayon.  The  stone  is  then  transferred  to  the  press  and  proofs  taken  in  the 
usual  way.  It  is  .said  that  excellent  pictures  have  been  obtained  from  the  stone  after  900 
copies  had  been  pulled. 

The  process  of  M.  Charles  Niegre,  which  has  excited  much  attention  in  Paris,  is  more 
complicated  than  the  preceding,  but  yields  superior  results.  His  process  appears  to  be  not 
unlike  that  of  M.  Fizeau.  He  employs  acids  to  cat  the  lines  into  the  plate,  and  at  a  certain 
stage  of  the  process  it  is  submitted  to  the  action  of  a  galvanic  bath  which  plates  it  with 
cojjper,  silver,  or  gold,  according  to  circumstances.  By  his  process  the  half-tones  are  pro- 
duced with  much  delicacy. 

Mr.  Fox  Talbot's  process  of  Photoglyphic  Engraving  has  been  thus  described  by 
himself: — 

"  I  employ  plates  of  steel,  copper,  or  zinc,  such  as  are  commonly  used  by  engravers. 
Before  using  a  plate  its  surface  should  be  well  cleaned  ;  it  should  then  be  rubbed  with  a 
linen  cloth  dipped  in  a  mixture  of  caustic  soda  and  whiting,  in  order  to  remove  any  remain- 
ing trace  of  greasiness..  The  plate  is  then  to  be  ruljbed  diy  with  another  linen  cloth.  This 
process  is  then  to  be  repeated  ;  after  which,  the  plate  is  in  general  sufficiently  clean. 


PHOTOGRAPHIC  ENGRAVING.  917 

"  In  order  to  engrave  a  plate,  I  first  cover  it  with  a  substance  which  is  sensitive  to  light. 
This  is  prepared  as  follows  : — About  a  quarter  of  an  ounce  of  gelatine  is  dissolved  in  eight 
or  ten  ounces  of  water,  b\'  the  aid  of  heat.  To  this  solution  is  added  about  one  ounce,  by 
measure,  of  a  saturated  solution  of  bichromate  of  potash  in  water,  and  the  mixture  is  strain- 
ed through  a  linen  cloth.  The  best  sort  of  gelatine  for  the  purpose  is  that  used  by  cooks 
and  confectioners,  and  commonly  sold  under  the  name  of  gelatine.  In  default  of  this, 
isinglass  may  be  used,  but  it  does  not  answer  60  well.  Some  specimens  of  isinglass  have 
an  acidity  which  slightly  corrodes  and  injures  the  metal  plates.  If  this  accident  occurs, 
ammonia  should  be  added  to  the  mixture,  which  will  be  found  to  correct  it.  This  mixture 
of  gelatine  and  bichromate  of  potash  keeps  good  for  several  months,  owing  to  the  antiseptic 
and  preserving  power  of  the  bichromate.  It  remains  liquid  and  ready  for  use  at  any  time 
during  the  summer  months;  but  in  cold  weather  it  becomes  a  jelly,  and  has  to  be  warmed 
before  using  it :  it  should  be  kept  in  a  cupboard  or  dark  place.  The  proportions  given 
above  are  convenient,  but  they  may  be  considerably  varied  without  injuring  the  result.  The 
engraving  process  should  be  c.irried  on  in  a  partially  darkened  room,  and  is  performed  as 
follows  : — A  little  of  this  prepared  gelatine  is  poured  on  the  plate  to  bo  engraved,  which  is 
the.i  held  vertical,  and  the  superfluous  liquid  allowed  to  drain  off  at  one  of  the  corners  of 
the  plate.  It  is  held  in  a  horizontal  position  over  a  spirit  lamp,  which  soon  dries  the  gela- 
tine, which  is  left  as  a  thin  film,  of  a  pale  yellow  color,  covering  the  metallic  surface,  and 
generally  bordered  with  seveial  narrow  bands  of  prismatic  colors.  These  colors  are  of  use 
to  tlie  operator,  by  enabling  liim  to  judge  of  the  thinness  of  the  film :  when  it  is  very  thin, 
the  prismatic  colors  are  seen  over  the  whole  surface  of  the  plate.  Such  plates  often  make 
excellent  engravings  ;  nevertheless,  it  is  perhaps  safer  to  use  gelatine  films  which  are  a  little 
thicker.  Experience  alone  can  guide  the  operator  to  the  best  result.  The  object  to  be 
engraved  is  then  laid  on  the  metal  plate,  and  screwed  down  upon  it  in  a  photographic  copy- 
ing fianie.  Such  objects  may  be  either  material  substances,  as  lace,  the  leaves  of  plants, 
&c.,  or  they  may  be  engravings,  or  writings,  or  photographs,  &c.,  &c.  The  plate  bearing 
the  object  upon  it  is  then  to  be  placed  in  the  sunshine,  for  a  space  of  time  varying  from  one 
to  several  minutes,  according  to  circumstances ;  or  else  it  may  be  placed  in  common  day- 
light, but  of  course  for  a  long  time.  As  in  other  photographic  processes,  the  judgment  of 
the  operator  is  here  called  into  play,  and  his  experience  guides  him  as  to  the  proper  time 
of  exposure  to  the  light.  When  the  frame  is  withdrawn  from  the  light,  and  the  object  re- 
moved fiom  the  plate,  a  faint  image  is  seen  upon  it — the  yellow  color  of  the  gelatine 
having  turned  brown  wherever  the  light  has  acted. 

"Tlie  novelty  of  the  present  invention  consists  in  the  improved  method  by  which  the 
photograpiiic  image,  obtained  in  the  manner  alcove  described,  is  engraved  upon  the  metal 
plate.  The  first  of  these  improvements  is  as  follows : — I  formerly  supposed  that  it  was 
necessary  to  wash  the  plate,  bearing  the  photographic  image,  in  water,  or  in  a  mixture  of 
water  and  alcohol,  which  dissolves  only  those  portions  of  the  gelatine  on  which  the  light  has 
not  acted  ;  and  I  believe  that  all  other  persons  who  have  employed  this  method  of  engrav- 
ing, by  means  of  gelatine  and  bichromate  of  potash,  have  followed  the  same  method,  viz., 
that  of  washing  the  photographic  image.  But  however  carefully  this  process  is  conducted, 
it  is  frequently  found,  when  the  plate  is  again  dr}',  that  a  slight  disturbance  of  the  image 
has  occurred  whicli,  of  course,  is  injurious  to  the  beauty  of  the  result;  and  I  have  now 
ascertained  that  it  is  not  at  all  necessary  to  wash  the  photographic  image  ;  on  the  contrary, 
much  more  beautiful  engravings  are  obtained  upon  plates  which  have  not  been  washed, 
becaijse  the  more  delicate  lines  and  details  of  the  picture  have  not  been  at  all  disturbed. 
The  process  which  I  now  employ  is  as  follows: — When  the  plate,  bearing  the  photograjihic 
image,  is  leniovod  from  the  copying  frame,  I  spread  over  its  surface,  carefully  and  very 
eveidy,  a  little  finely-powdered  gum  copal  (in  default  of  which  common  resin  may  be  cm- 
ploycil).  It  is  much  easier  to  spread  this  resinous  powder  evenly  upon  the  surface  of  gela- 
tine, than  it  is  to  do  so  upon  the  naked  surfiice  of  a  metal  plate.  The  chief  error  the 
operator  has  to  guard  against  is,  that  of  putting  on  too  much  of  the  powder  :  the  best  results 
are  oI)tained  by  using  a  very  thin  layer  of  it,  jirovided  it  is  uniforndy  distributed.  If  too 
much  of  the  powder  is  laid  on  it  impedes  the  action  of  the  etching  liipiid.  When  the  plate 
has  been  thus  very  thinly  powdered  with  copal,  it  is  held  horizoutally  over  a  sjiirit  lamp  in 
ordei-  to  melt  the  co|)al ;  this  re(iun'es  a  considerable  heat.  It  might  be  supposed  that  this 
heating  of  the  plate,  alter  the  formation  of  a  delicate  photograpiiic  image  upon  it,  would 
distuH)  and  injure  that  image ;  but  it  has  no  such  elfect.  .  The  melting  of  the  copal  is  known 
by  the  change  of  color.  The  plate  should  then  be  withdiawn  from  the  lamp,  and  suffered 
to  cool.  Tiiis  process  may  be  called  the  laying  an  a(iuatint  ground  ui)on  the  gelatine,  and 
'I  believe  it  to  Ije  a  new  process.  In  the  common  mode  of  laying  an  aquatint  giound,  the 
•  resinous  particles  are  laid  iqion  the  naked  stnl'ace  of  the  metal,  before  the  engraving  is 
commenced.  The  gelatine  being  tiius  covereil  with  a  layer  of  copal,  disseminated  uniforndy 
and  iu  minute  particles,  the  etching  rK|uid  is  to  be  jxiured  on.  This  is  prejiared  as  lol- 
lop.- :  —  Muriatic  acid,  otlierwise  called  liyilrochloric  a''iil,  is  saturated  with  peroxide  of  iron, 
as  much  iLs  it  will  dis.solvc  with  the  aid  of  heat.     After  stiainiug  the  solution,  to  remove 


918  PHOTOGRAPHY. 

imptiritios,  it  is  cvapoiated  till  it  is  considerably  reduced  in  volume,  and  is  tlien  poured  off 
into  bottles  of  a  convenient  capacity  ;  as  it  cools  it  solidiiies  into  a  brown  semi-crystalline 
nia.-s.  The  bottles  are  then  well  corked  up,  and  kept  for  use.  I  shall  call  this  preparation 
of  iron  by  the  name  of  pcrchloride  of  iron  in  the  present  specification,  as  I  believe  it  to  be 
identical  with  t'le  substance  described  by  chemical  authors  under  that  name — for  example, 
see  7'iinicr\s  Ch.i>iixtr;j,  fifth  edition,  pa<;e  5y7  ;  and  by  others  called  permuriate  of  iron 
— lor  example,  see  Bru^rs  JLninul  of  C/iei/us/rt/,  second  edition,  vol.  ii.  page  117. 

"  It  is  a  substance  very  attractive  of  moisture.  "When  a  little  of  it  is  taken  from  a 
bottle,  in  the  form  of  a  dry  powder,  and  laid  upon  a  plate,  it  quickly  deliquesces,  absorbing 
the  atmospheric  moisture.  In  solution  in  water,  it  forms  a  yellow  liquid  in  small  thicknesses, 
but  chesnut-brown  in  greater  thicknesses.  In  order  to  render  its  mode  of  action  in  photo- 
grapliic  engraving  more  intelligible,  I  will  first  state,  that  it  can  be  very  usefully  employed 
in  common  etching ;  that  is  to  say,  if  a  plate  of  copper,  steel,  or  zinc  is  covered  with  an 
etching  ground,  and  lines  are  traced  on  it  with  a  needle's  point,  so  as  to  form  any  artistic 
subject ;  then,  if  the  solution  of  perchloride  of  iron  is  poured  on,  it  quickly  effects  an  etch- 
ing, and  does  this  without  disengaging  bubbles  of  gas,  or  causing  any  smell ;  for  which 
reason  it  is  much  more  convenient  to  use  than  aquafortis,  and  also  because  it  does  not  in- 
jure the  operator's  hands  or  his  clothes  if  spilt  upon  them.  It  may  be  employed  of  various 
strengths  for  common  etching,  but  requires  peculiar  management  for  photoglyphic  engrav- 
ing ;  and  as  the  success  of  that  mode  of  engraving  chiefly  turns  upon  this  point,  it  should 
be  well  attended  to. 

"  Water  dissolves  an  extraordinary  quantity  of  perchloride  of  iron,  sometimes  evolving 
much  heat  during  the  solution.  I  find  that  the  following  is  a  convenient  way  of  pro- 
ceeding:— 

"A  bottle  (Xo.  1)  is  filled  with  a  saturated  solution  of  perchloride  of  iion  in  water. 

"  A  bottle  (Xo.  2)  with  a  mixture,  consisting  of  live  or  six  parts  of  the  saturated  solution 
and  one  part  of  water. 

"  And  a  bottle  (Xo  ?>)  with  a  weaker  liquid,  consisting  of  equal  parts  of  water  and  the 
saturated  solution.  Before  attempting  an  engraving  of  importance,  it  is  almo.-t  essential  to 
make  i)reliminary  trials,  in  order  to  ascertain  that  tliese  liquids  are  of  the  proper  strengths. 
These  trials  I  shall  therefore  now  proceed  to  point  out.  I  have  already  explained  how  the 
photographic  image  is  made  on  the  surface  of  the  gelatine,  and  covered  with  a  thin  layer 
of  powdered  copal  or  resin,  which  is  then  melted  by  holding  the  plate  over  a  lamp.  When 
the  jilite  has  become  perfectly  cold,  it  is  ready  for  the  etching  process,  which  is  performed 
as  follows  • — A  small  (luantity  of  the  solution  in  bottle  Xo.  2,  viz.  that  consisting  of  five  or 
six  paits  of  the  saturated  sohition  to  one  of  water,  is  poured  upon  the  plate,  and  spread 
witli  a  camel-hair  brush  cveidy  all  over  it.  It  is  not  necessary  to  make  a  wall  of  wax  round 
the  plate,  because  the  quantity  of  liquid  employed  is  so  small  that  it  has  no  tendency  to 
rim  otfthe  plate.  The  liquid  penetrates  the  gelatine  wherever  the  light  has  not  acted  on  it, 
but  it  refuses  to  penetrate  those  parts  upon  which  the  light  has  sufficiently  acted.  It  is 
upon  this  remarkable  fact  that  the  art  of  photoglyphic  engraving  is  maiidy  founded.  In 
aliout  a  minute  tlie  etching  is  seen  to  begin,  which  is  known  by  the  parts  etched  turning 
d.u  k  brown  or  black,  and  then  it  spreads  over  the  whole  plate — the  details  of  the  picture 
appealing  with  great  rapidity  in  every  ([uarter  of  it.  It  is  not  desirable  that  this  rapidity 
should  be  too  great,  for,  in  that  case,  it  is  necessary  to  stop  the  process  before  the  etcliing 
has  ac(iuired  sufficient  depth  (which  recjuires  an  action  of  some  minutes' duration).  If, 
therefore,  the  etching,  on  trial,  is  found  to  proceed  too  rapidly  the  strength  of  the  liquid  in 
bottle  Xo.*  2  must  be  altered  (l)y  adding  some  of  the  saturated  solution  to  it  before  it  is 
employed  for  another  engraving);  but  if,  on  the  contrary,  the  etching  fails  to  occur  after 
the  lapse  of  some  minutes,  or  if  it  begin.s,  but  proceeds  too  slowly,  this  is  a  sign  that  the 
li.|Uid  ill  bottle  Xo.  2  is  too  strong,  and  too  nearly  ajjpioacliing  saturation.  To  correct  this, 
a  little  water  must  lie  added  to  it  before  it  is  employed  for  another  engraving.  But,  in 
doing  this,  the  operator  must  take  notice,  tliat  a  very  minute  (piantity  of  water  added  often 
mikes  a  great  dilference,  and  causes  the  li(iuid  to  etch  very  rapidly.  He  will  therefore  be 
careful  in  adding  water,  not  to  do  so  too  freely.  When  the  proper  strength  of  the  solution 
in  bottle  Xo.  2  has  thus  been  adjusted,  which  generally  requires  three  or  four  expeiiinental 
trial.-i,  it  can  be  employed  with  .security.  Supposing,  then,  that  it  has  been  ascertained  to 
be  of  the  riglit  stiength,  the  etching  is  commenced,  as  above  mentioned,  and  proceeds  till 
ail  the  details  of  the  ])icture  have  l)een  visible,  and  present  a  .satisfactory  a{)peaiance  to  the 
eye  of  the  operator,  which  generally  occuis  in  two  oi-  three  minutes;  the  operator  stirring 
the  liquid  all  the  time  with  a  camel-hair  bru.sh,  and  thus  .-flight ly  rubbing  the  surface  of  the 
gelaiiue,  which  has  a  good  effect.  When  it  seems  likely  that  the  etching  will  improve  no 
fuither,  it  must  be  slopped.  This  is  done  by  wiping  off  the  li(iuid  with  cotton  wool,  and 
then  rapidly  pouring  a  stream  of  cold  water  over  the  plate,  which  carries  off  all  the  remain- 
der of  it.  The  plate  is  then  wiped  with  a  clean  linen  cloth,  and  then  rubbed  with  soft 
whiiiii'r  and  water  to  remove  the  gelatine.     The  etcliing  is  then  found  to  be  completed. 

i'llUTUGRAI'ilV.      (From  photo,  light;  (/ruph:,ii  writing  or  a  description.)     The  art 


PHOTOGKAPHY. 


919 


of  producing  pictures  by  the  agency  of  sunshine,  acting  upon  chemically  prepared  papers. 
The  name  appears  unfortunate,  since  we  are  persuaded  that  it  is  not  light — that  is,  the. 
luminous  principle  of  the  sunshine,  which  effects  tlie  chemical  change,  but  a  peculiar  prin- 
ciple or  power  which  is  associated  with  light  in  the  sunbeam.  In  the  metaphysical  refine- 
ments of  our  modern  philosophy,  which  endeavors  to  refer  every  physical  i)henomenon  to 
some  peculiar  mode  of  motion,  we  are  apt  to  lose  sight  of  the  stern  facts,  which,  in  spite  of 
the  enormous  amount  of  talent  which  has  been  brought  to  bear  on  the  whole  series  of  un- 
dulatory  hypotheses,  still  stand  out  as  unreconeilable  with  any  of  these  views.  If  llglit  is 
motion,  and  shaihw  degrees  of  repose,  it  remains  unexplained  how  the  most  intense  inotion, 
yellow  light,  not  only  produces  no  chemical  change,  but  actually  prevents  it ;  or  how  the  deep 
shadow  of  the  non-luminoux  rays  produces  the  most  active  chemical  decomposition.  M. 
Xiepce,  in  1827,  called  his  interesting  discovery  Hkliography,  or  sun-writing.  This  name, 
as  involving  no  hypothesis,  was  an  exceedingly  happy  one,  and  it  is  to  be  regretted  that  it 
was  not  adopted. 

In  this  dictionary  it  is  our  purpose  only  to  deal  with  the  chief  principles  involved  in  this 
very  interesting  art,  and  to  give  brief  descriptions  of  some  of  the  more  remarkable  and 
interesting  of  the  processes  which  have  been  introduced.  There  are  certain  chemical  com- 
pounds, and  especially  some  of  the  salts  of  silver,  which  are  rapidly  decomposed  by  the 
iiithii'ncft  of  the  sunshine,  and  even,  though  more  slowly,  by  ordinary  daylight,  or  powerful 
artificial  light.  As  the  extent  to  which  the  decomposition  is  carried  on  depends  upon  the 
intensity  of  radiation  proceeding  from  the  object,  or  passing  through  it,  accordingly  as  we 
are  employing  the  reflected  or  the  transmitted  rays,  it  will  be  obvious  that  we  shall  obtain 
very  delicate  gradations  of  dai-kening,  and  thus  the  photograph  will  represent  in  a  very 
refined  manner  all  those  details  which  are  rendered  visible  to  the  eye  by  light  and  shadow. 

There  are  two  methods  by  which  photographs  can  be  taken  :  the  first  and  simplest  is  by 
supcr-positio7i ;  but  this  is  applicable  only  to  the  copying  of  engravings  of  such  botanical 
specimens  as  can  be  spread  out  upon  paper,  and  objects  which  are  entirely  or  in  part  trans- 
parent. The  other  method  is  by  throwing  upon  the  prepared  paper  the  image  obtained  by 
the  use  of  a  lens  fitted  into  a  dark  box — the  camera  obscura. 

To  carry  out  either  of  those  methods,  certain  sensitive  surfaces  must  be  produced  ;  these, 
therefore,  claim  our  first  attention : — The  artist  requires 

1.  Nitrate  of  silver. 

2.  Ammonia  nitrate  of  silver. 

3.  Chloride  of  silver. 

4.  Iodide  of  silver. 

5.  Bromide  of  silver. 

Those  five  chemical  compounds  may  be  regarded  as  the  agents  most  essential  in  the  prepa- 
ration of  photographic  surfaces. 

1.  Nitrate  of  Silver.  The  crystallized  salt  should,  if  possible,  always  be  procured. 
The  fused  nitrate,  which  is  sold  in  cylindrical  sticks,  is  more  liable  to  contamination,  and 
the  paper  in  which  each  stick  of  two  drachms  is  wrapped  being  weighed  with  the  silver,  ren- 
ders it  less  economical.  A  preparation  is  sometimes  sold  for  nitrate  of  silver,  at  from  Gd. 
to  9d.  the  ounce  less  than  the  ordinary  price,  which  may  induce  the  unwary  to  purchase  it. 
Tliis  reduction  of  price  is  effected  by  fusing  with  the  salt  of  silver  a  proportion  of  some 
cupreous  salt,  generally  the  nitrate,  or  nitrate  of  potash.  This  fraud  is  readily  detected  by 
oljSLTving  if  the  salt  becomes  moist  on  exposure  to  the  air — a  very  small  admixture  of  cop- 
per rendering  the  nitrate  of  silver  deliquescent.  The  evils  to  the  photographer  are,  want 
of  sensibility  upon  exposure,  and  the  perishability  (even  in  the  dark)  of  the  finished 
drawing. 

The  most  simple  kind  of  photographic  paper  which  is  prepared,  is  that  washed  with  the 
nitrate  of  silver  only  ;  and  for  many  purposes  it  answers  remarkably  well,  particularly  for 
copying  lace  or  feathers ;  and  it  has  this  advantage  over  every  other  kind,  that  it  is  perfectly 
fixed  by  well  soaking  in  pure  warm  water. 

The  best  proportions  in  which  this  salt  can  be  used  arc  60  grains  of  it  dissolved  in  a 
fluid  ounce  of  water.  Care  must  be  taken  to  apply  it  equally,  witli  a  quick  but  steady  mo- 
tion, over  every  part  of  the  paper.  It  will  be  found  the  best  practice  to  pin  the  sheet  by 
its  four  corners  to  a  flat  board,  and  then,  holding  it  with  the  left  hand  a  little  inclined,  to 
sweep  the  brusli  from  the  upper  outside  corner,  over  the  whole  of  the  sheet,  removing  it  as 
seldom  as  possible. 

The  nitrated  paper  not  Vjcing  very  sensitive  to  hnninous  agency,  it  is  desirable  to  increase 
its  power.     This  may  be  done  to  some  extent  by  simple  metliods. 

By  soaking  the  pajier  in  a  solution  of  isinglass  or  parchment  size,  or  by  rubbing  it  over 
with  the  white  of  egg,  and  drying  it  prior  to  the  application  of  the  sensitive  wash,  it  will  be 
found  to  blacken  much  more  readily,  and  assume  different  tones  of  color,  which  may  be 
▼arii'd  at  the  taste  of  the  operator. 

By  dissolving  the  nitrate  of  silver  in  common  rectified  sjjirits  of  wine  instead  of  water, 
we  produce  a  tolerably  sensitive  nitrated  paper,  wiiicli  darkens  to  a  very  h(>Mutirul  chocolate 


920 


PHOTOGRAPHY. 


brown  ;  but  this  wash  must  not  be  used  on  any  sheets  prepared  with  isinglass,  parchment 
or  albumen,  as  these  substances  are  coagulated  by  alcohol. 

2.  Ammonia  Nitrate  of  Silver.  Liquid  ammonia  is  to  be  dropped  carefully  into 
nitrate  of  silver ;  a  dark  oxide  of  silver  is  thrown  down  ;  if  the  ammonia  liquor  is  added 
in  excess,  this  precipitate  is  redissolved,  and  we  obtain  a  perfectly  colorless  solution.  Paper 
washed  with  this  solution  is  more  sensitive  than  that  prepared  with  the  ordinary  nitrate. 

?>.  CiiLORiiiE  OF  Silver.  This  salt  is  obtained  most  readily  by  pouring  a  solution  of 
common  salt,  chloride  of  sodium,  into  a  solution  of  nitrate  of  silver.  It  then  falls  as  a  pure 
white  precipitate,  which  rapidly  changes  color  even  in  diffused  daylight. 

Chloridated  jjupcrs,  as  ihcy  are  termed,  arc  formed  by  producing  a  chloride  of  silver  on 
their  surface,  by  washing  the  paper  with  the  solution  of  chloride  of  sodium,  or  any  other 
chloride,  and  when  the  paper  is  dry,  with  the  silver  solution. 

It  is  a  very  instructive  practice  to  prejiare  small  quantities  of  solutions  of  common  salt 
and  nitrate  of  silver  of  different  strengths,  to  cover  slips  of  paper  with  thom  in  various 
ways,  and  then  to  expose  them  all  to  the  same  radiations.  A  curious  variety  in  the  degrees 
of  sensibility,  and  in  the  intensity  of  color,  will  be  detected,  showing  the  impoi'tance  of  a 
very  close  attention  to  proportions,  and  also  to  the  mode  of  manipulating. 

A  knowledge  of  these  preliminary  but  important  points  having  been  obtained,  the  prepa- 
ration of  the  paper  should  be  proceeded  with  ;  and  the  following  method  is  recommended  : 

Taking  some  flat  deal  boards,  perfectly  clean,  pin  upon  them,  by  their  four  corners,  the 
paper  to  be  prepared  ;  observing  the  two  sides  of  the  paper,  and  selecting  that  side  to  re- 
ceive the  preparation  which  presents  the  hardest  and  most  uniform  surface.  Then,  dipping 
a  sponge  brush  into  the  solution  of  chloride  of  sodium,  a  sufficient  quantity  is  taken  up  by 
it  to  moisten  the  surface  of  the  paper  without  any  hard  rubbing ;  and  this  is  to  be  applied 
with  great  regularity.  The  papers  being  "  salted,"  are  allowed  to  dry.  A  great  number 
of  these  may  be  prepared  at  a  time,  and  kept  in  a  portfolio  for  use.  To  render  these  sensi- 
tive, the  papers  being  pinned  on  the  boards,  or  carefully  laid  upon  folds  of  white  blotting- 
paper,  are  to  be  washed  over  with  the  nitrate  of  silver,  applied  by  means  of  a  camePs-hair 
pencil,  observing  the  instructions  previously  given  as  to  the  method  of  moving  the  brush 
upon  the  paper.  After  the  first  wash  is  applied,  the  paper  is  to  be  dried,  and  then  sub- 
jected to  a  second  application  of  the  silver  solution.  Thus  prepared,  it  will  be  sufficiently 
sensitive  for  all  purposes  of  copying  by  application. 

T7ie  most  sensitive  paper. — Chloride  of  sodium,  30  grains  to  an  ounce  of  water ;  nitrate 
of  silver,  120  grains  to  an  ounce  of  distilled  water. 

The  paper  is  first  soaked  in  the  saline  solution,  and  after  being  carefully  wiped  with  linen, 
or  pressed  between  folds  of  blotting-paper  and  dried,  it  is  to  be  washed  twice  with  the  solu- 
tion of  silver,  drying  it  by  a  warm  fire  between  each  washing.  This  paper  is  very  liable  to 
become  brown  in  the  dark.  Although  images  may  be  obtained  in  the  camera  obscura  on 
this  paper  by  about  half  an  hour's  exposure,  they  are  never  very  distinct,  and  may  be  re- 
garded as  rather  curious  than  useful. 

Less  sensitive  paper  for  copies  of  cneiravivgs  or  botanical  specimens. — Chloride  of  so- 
dium, 25  grains  to  an  ounce  of  water ;  nitrate  of  silver,  99  grains  to  an  ounce  of  distilled 
water. 

Common  sensitive  paper,  for  copying  lace-icork,  feathers,  d'c. — Chloride  of  sodium,  20 
grains  to  an  ounce  of  water ;  nitrate  of  silver,  60  grains  to  an  ounce  of  distilled  water. 

This  paper  keeps  tolerably  well,  and,  if  carefully  prepared,  may  always  be  depended 
upon  for  darkening  equally. 

4.  Iodide  of  Silver.  This  salt  was  employed  very  early  by  Talbot,  (see  Calotype, 
vol.  i.,)  Ilcrschel,  and  others,  and  it  enters  as  the  principal  agent  into  Mr.  Talbot's  calotype 
paper.  Paper  is  washed  with  a  solution  of  the  iodide  of  potassium,  and  then  with  nitrate 
of  silver.  By  this  means  papers  may  be  prepared  which  are  exquisitely  sensitive  to  lumi- 
nous influence,  provided  the  right  proportions  are  hit ;  but,  at  the  same  time,  nothing  can 
be  more  insensible  to  the  same  agency  than  the  pure  iodide  of  silver.  A  singular  difference 
in  precipitates  to  all  appearance  the  same  led  to  the  belief  that  more  than  one  definite  cou)- 
pound  of  iodine  and  silver  existed  ;  but  it  is  now  proved  that  pure  iodide  of  silver  will  not 
change  color  in  the  sunshine,  and  that  the  quantity  of  nitrate  of  silver  in  excess  regulates 
the  degree  of  sensibility.  Experiment  has  proved  that  the  blackening  of  one  variety  of 
iodated  paper,  and  the  preservation  of  another,  depend  on  the  simple  admixture  of  a  very 
minute  excess  of  the  nitrate  of  silver.  The  papers  prepared  with  the  iodide  of  silver  have 
.'ill  the  peculiarities  of  those  prepared  with  the  chloride,  and  although,  in  some  instances, 
they  seem  to  exhibit  a  much  higher  order  of  sensitiveness,  they  cannot  be  rccommer^lcd 
for  general  purposes  with  that  confidence  which  experience  has  given  to  the  chloride. 

u.  Bromide  of  Silver.  In  many  of  the  works  on  chemistry,  it  is  stated  that  the  chfo- 
ride  is  the  most  sensitive  to  light  of  all  the  salts  of  silver ;  and,  when  they  arc  exposed  in 
a  perfectly  formed  and  pure  state  to  solar  influence,  it  will  be  found  that  this  is  nearly  cor- 
rect. Modern  discovery  has,  however,  ."shown  that  these  salts  may  exist  in  peculiar  condi- 
tions, in  which  the  affinities  are  so  delicately  balanced  as  to  be  disturbed  by  the  faintest 


PHOTOGRAPHY. 


921 


gleam ;  and  it  is  singular  that,  as  it  regards  the  chloride,  iodide,  and  bromide  of  silver, 
when  in  this  condition^  tlie  order  of  sensibility  is  reversed,  and  the  most  decided  action  is 
evident  on  the  bromide  before  the  eve  can  detect  any  change  in  the  chloride. 

To  prepare  a  higbly  sensitive  paper  of  this  kind,  select  some  sheets  of  very  superior 
glazed  post,  and  wash  it  on  one  side  only  with  bromide  of  potassium — iO  grains  to  1  ounce 
of  distilled  water,  over  which,  when  dry,  pass  a  solution  of  100  grains  of  nitrate  of  silver 
in  the  same  quantity  of  water.  The  paper  must  be  dried  as  quickly  as  possible  without  es- 
posin"'  it  to  too  much  heat ;  then  again  washed  with  the  silver  solution,  and  diied  in  the 
dark.°  Such  are  the  preparations  of  an  ordinary  kind,  with  which  the  photographer  will 
proceed  to  work. 

The  most  simple  method  of  obtaining  suu-pictures,  is  that  of  placing  the  objects  to  be 
copied  on  a  piece  of  prepared  paper,  pressing  them  close  by  a  piece  of  glass,  and  exposing 
the  arrangement  to  sunshine :  all  the  parts  exposed  darken,  while  those  covered  are  pro- 
tected from  change,  the  resulting  picture  being  white  upon  a  durk  ground. 

For  the  muhrplication  of  photogniphic  drawings,  it  is  necessary  to  be  provided  with  a 
frame  and  glass,  called  a  copying  frame.     The  glass  must  be  oi  such  thickness  as  to  resist 


considerable  pressure,  and  it  should  be  selected  as  colorless  as  possible,  great  care  being 
taken  to  avoid  such  as  have  a  tint  of  yellow  or  red,  these  colors  preventing  the  permeation 
of  the  most  efficient  rays ;  fig.  559  represents  the  frame,  showing  the  back,  with  its  ad- 
justments for  securing  the  close  contact  of  the  paper  with  every  part  of  the  object  to  be 
copied. 

Having  placed  the  frame  face  downward,  carefully  lay  out  on  the  glass  the  object  to  be 
copied,  on  which  place  the  photographic  paper  very  smoothly.  Having  covered  this  with 
the  cushion,  which  may  be  either  of  flannel  or  velvet,  fix  the  back,  and  adjust  it  by  the  bar, 
until  every  part  of  the  object  and  paper  is  in  the  closest  possible  contact ;  then  turn  up 
the  frame  and  expose  to  sunshine. 

It  should  be  here  stated,  once  for  all,  that  such  pictures,  howsoever  obtained,  are  called 
negative  photographs ;  and  those  which  have  their  lights  and  shadows  correct  as  in  nature — 
dark  upon  a  light  ground — are  positive  photographs.  The  mode  of  effecting  the  produc- 
tion of  a  positive  is:  having,  by  fixing,  given  permanence  to  the  negative  picture,  it  is 
placed,  face  down,  on  another  piece  of  sensitive  paper,  when  all  the  parts  which  are  white 
on  the  first,  admitting  light  freely,  cause  a  dark  impression  to  be  made  on  the  second,  and 
the  resulting  image  is  correct  in  its  lights  and  shadows,  and  also  as  it  regards  right  and 
left. 

For  obtaining  pictures  of  external  nature,  the  camera  obscura  of  Baptista  Porta  is  cm- 
ployed. 


6G1 


562 


The  figures  {figs.  560,  561,  5C2)  represent  a  perfect  arrangement,  and.  at  the  same  time, 
one  which  is  not  essentially  expensive.  Its  conveniences  are  those  of  folding,  {Jig.  562,) 
and  thus  packing  into  a  very  small  compass,  for  the  convenience  of  travellers. 

I'ig.  560  exhibits  the  instrument  complete.  Fig.  561  shows  the  screen  in  which  the 
sensitive  paper  is  placed,  the  shutter  being  up  and  the  frame  open  that  its  construction  may 
be  seen. 


922 


PHOTOGRAPHY. 

563 


5i34 


Camera  obscuras  of  a  more  elaborate  character  are  constructed,  and  many  of  exceeding 
ingenuity,  wliich  give  every  f^icility  for  carrying  on  tbe  manipulations  for  the  collodion 
process,  to  be  presently  described,  out  of  doors.  The  preceding  is  a  camera  obscura  of  this 
kind,  manufactured  by  Mr.  John  Joseph  Griffin,  of  Bunhill  Row. 

This  is  really  Mr.  Scott  Archer's  camera  obscura  improved  upon.  Fig.  563  is  a  section 
of  the  instrument,  and  Jig.  5G4  its  external  form.  With  a  view  to  its  portability,  it  is  con- 
structed so  as  to  serve  as  a  packing-case  for  all  the  apparatus  required,  a  is  a  sliding  door 
wliich  supports  the  lens,  b.  c,  c,  are  side  openings  fitted  with  cloth  sleeves  to  admit  the 
operator's  arms.  J  is  a  hinged  door  at  the  back  of  the  camera,  which  can  be  supported  like 
a  table  by  the  hook  c.  f  is  the  opening  for  looking  into  the  camera  during  an  operation. 
This  opening  is  closed  when  necessary  by  the  door  g,  which  can  be  opened  by  the  hand 
passed  into  the  camera  through  the  sleeves  c.  The  yellow  glass  window  which  admits  light 
into  the  camera  during  an  operation  is  under  the  door  h.  i  is  the  sliding  frame  for  holding 
the  focusing  glass,  or  the  frame  with  the  prepared  glass,  cither  of  which  is  fastened  to  the 
sliding  frame  by  the  check  k.  The  frame  slides  along  the  rod  /  /,  and  can  be  fitted  to  the 
proper  focus  by  means  of  the  step  m.  n  is  the  gutta-percha  washing-tray,  o  is  an  opening 
in  the  bottom  of  the  instrument  near  the  door,  to  admit  the  well  p,  and  which  is  closed  when 
the  well  is  removed  by  the  door.  The  well  is  divided  into  two  cells,  one  of  which  contains 
the  focusing  glass,  and  the  other  the  glass  trough,  each  in  a  frame  adapted  to  the  sliding 
frame  i.  On  each  side  of  the  sliding  door  that  supports  the  lens  «,  there  is  within  the 
camera  a  small  hinged  table,  ?-,  supported  by  a  bracket,  s.     These  two  tables  serve  to  sup- 


PHOTOGRAPHY. 


923 


port  the  bottles  that  contain  the  solutions  necessary  to  be  applied  to  the  glass  plate  after  its 
exposure  to  the  lens. 

For  supporting  any  of  these  camera  obscuras,  tripod  stands  are  employed ;  these  are 
now  made  in  an  exceedingly  convenient  form,  being  light,  af  the  same  time  that  they  are 
sufficiently  firm  to  secure  tlie  instrument  from  any  motion  during  the  operation  of  taking  a 
])icture. 

The  true  photographic  artist,  however,  will  not  be  content  with  a  camera  obscura  of  this 
or  any  otiicr  kind.  lie  will  provide  himself  with  a  tent,  in  which  he  may  be  able  to  pre 
pare  liis  plates,  and  subsequently  to  develop  and  to  fix  liis  pictures.  Many  kinds  of  tent 
have  been  brought  forward,  but  we  have  not  seen  any  one  which  unites  so  perfectly  all  that 
can  be  desired,  witliin  a  limited  space,  and  which  shall  have  the  great  recommendation  of 
lightness.  Fig.  5f)5  represents  Smartt's  new  photographic  tent,  which  appears  to  meet 
nearly  all  the  conditions  required. 


In  this  tent  an  endeavor  has  been  made  to  obviate  many  of  the  inconveniences  com- 
plained of,  especially  as  to  working  space,  firmness,  siniplicit}.,  and  portability.  Usually,  in 
tlio  various  forms  of  tent,  the  upper  part,  where  space  is  most  required,  is  the  most  con- 
tracted, while  at  the  lower  part,  where  it  is  of  little  importance,  a  great  amount  of  room  is 
provided. 

Smartt's  tent,  made  by  Murray  k  Heath,  is  rectangular  in  form,  is  G  feet  high  in  the 
clear,  and  3  feet  square,  affording  table  space  equal  to  ;5()  inches  by  ]8  inches,  and  ample 
room  for  the  operator  to  manipulate  with  perfect  ease  and  convenience.  The  chief  feature 
in  its  construction  is  the  peculiarity  of  its  framework,  which  constitutes,  when  erected,  a 
system  of  triangles,  so  disposed  as  to  strengthen  and  support  each  other:  it  thus  combines 
the  two  important  qualities  of  lightness  and  rigidity.  The  table  is  made  to  fold  up  when 
not  in  use ;  and  in  place  of  the  ordinary  dish  for  developing,  a  very  efficient  and  portable 
tray  is  provided,  made  of  india-rubber  cloth,  having  its  two  sides  fixed  and  rigid  and  its  two 


924  PHOTOGRAPHY. 

ends  movable  ;  it  thus  folds  up  into  a  space  but  little  larger  than  one  of  its  sides.  The 
working  .«pace  of  the  tal)le  is  economized  thus  : — a  portion  of  it  is  occupied  by  the  tray  just 
described  ;  the  silver-bath  (which  is  one  of  Murray  &  Heath's  new  glass  baths,  with' glass 
water-tight  top)  is  suspended  from  the  front  of  the  table,  and  rests  upon  a  portion  of  the 
framework  of  the  tent ;  a  contrivance  is  devised  for  disposing  of  the  plate-slide  of  the 
camera,  in  order  to  reserve  the  space  it  would  require  if  placed  on  the  table.  The  bath  and 
jjlate-holder,  in  their  places  as  described,  are  shown  in  the  wood-cut.  This  arrangement 
Itjaves  ample  space  on  the  table  for  manipulating  the  largest-sized  plates.  The  entire  weight 
of  the  tent  is  20  lbs.,  and  it  is  easily  erected  or  taken  down  by  one  person. 

The  collodion  pourer,  the  plate-developing  holder,  the  developing  cups,  and  the  water- 
bottle,  (the  latter  is  suspended  over  the  tray  as  in  the  wood-cut,)  have  all  special  points  in 
construction. 

The  object  of  the  inventor  has  been  completely  realized,  the  operator  being  insured  the 
means  of  working  the  wet-collodion  process  in  the  open  air  with  ease,  comfort,  and  conve- 
nience. Hitherto  this  has  not  been  possible,  in  consequence  of  the  great  weight  and  bulk 
of  the  contrivances  used,  and  to  which  niay  be  traced  the  existence  of  the  many  expedients 
for  retaining,  inore  or  less,  the  sensitiveness  of  thf>  prepared  plate. 

The  object  of  the  inventor  has  been  to  make  a  tent  whicli  shall  be  so  efficient  as  to  en- 
sure to  the  operator  the  means  of  working  the  wet  collodion  process  in  the  open  air  with 
ease,  comfort,  and  convenience. 

The  processes  of  most  importance  may  be  divided  as  follows : — 

1.  The  copying  process,  already  described. 

2.  The  Daguerreoti/pe,  the  earliest  method  successfully  employed  for  obtaining  pictures 
by  means  of  the  camera  obscura.     See  Daguerkeottpk. 

3.  The  Calotype  of  Mr.  H.  Fox  Talbot,  in  which  the  sensibility  of  the  iodide  of  silver 
is  exalted  by  the  agency  of  that  peculiar  organic  compound,  gallic  acid.     See  Calotype. 

4.  The  Collodion  process,  which  must  be  succinctly  described  h(  reaftcr. 

In  addition  to  the  ordinary  form  of  the  calotype  process  as  devised  by  Mr.  Fox  Talbot, 
and  of  which  an  account  has  been  given  under  the  proper  head,  the  Wax-pjaper  process  de- 
mands some  attention.  The  following  directions  are  those  given  by  Mr.  Wm.  Crookes,  who 
has  devoted  much  attention  to,  and  who  has  been  eminently  successful  with,  the  wax- 
paper: — 

The  first  operation  to  be  performed  is  to  make  a  slight  pencil-mark  on  that  side  of  the 
paper  which  is  to  receive  the  sensitive  coating.  If  a  sheet  of  Canson's  paper  be  examined 
in  a  good  light,  one  of  the  sides  will  be  ibund  to  present  a  finely  reticulated  appearance, 
while  the  other  will  be  perfectly  smooth ;  this  latter  is  the  one  that  sliould  be  marked. 
FilYy  or  a  hundred  .sheets  may  be  marked  at  once,  by  holding  a  pile  of  them  firmly  by  one 
end,  and  then  bending  the  packet  round,  until  the  loose  ends  separate  one  from  another  like 
a  fan :  generally  all  the  sheets  lie  in  the  same  direction,  therefore  it  is  only  necessary  to 
ascertain  that  the  smooth  side  of  one  of  them  is  uppermost,  and  then  draw  a  pencil  once  or 
twice  along  the  exposed  edges 

The  paper  has  now  to  be  saturated  with  white  wax.  The  wax  is  to  be  made  perfectly 
liquiJ,  and  then  the  sheets  of  paper,  taken  up  singly  and  l;eld  by  one  end,  are  gradually 
lowered  on  to  the  fluid.  As  soon  as  the  wax  is  absorbed,  which  takes  place  almost  directly, 
they  are  to  be  lifted  up  witli  rather  a  quick  movement,  held  by  one  corner,  and  allowed  to 
drain  until  the  wax,  ceasing  to  run  off,  congeals  on  the  surface.  "When  the  sheets  are  first 
taken  up  for  this  operation,  they  should  be  briefly  examined,  and  such  as  show  the  water- 
mark, contain  any  i)lack  spots,  or  have  any  thing  unusual  about  their  appearance,  should  be 
rejected. 

Tiie  paper  in  this  stage  will  contain  far  more  wax  than  necessary ;  the  excess  may  be 
removed  by  placing  the  .sheets  singly  between  blotting-paper,  and  ironing  them  ;  but  this  is 
wasteful,  and  the  loss  may  be  avoided  by  placing  on  each  side  of  the  waxed  sheet  two  or 
three  sheets  of  unwaxed  photographic  paper,  and  then  ironing  tlie  whole  between  blotting- 
paper  ;  there  will  generally  be  enough  wax  on  the  centre  sheet  to  saturate  fully  those  next 
to  it  on  each  side,  and  partially,  if  not  entirely,  the  others.  Tliose  that  are  imperfectly 
waxed  may  be  made  the  outer  sheets  of  the  succeeding  set.  Finally,  each  sheet  must  be 
separately  ironed  between  blotting-paper,  until  the  g'istcning  patches  of  wax  are  absorbed. 

It  is  of  the  utmost  consequence  that  the  temperature  of  the  iron  should  not  exceed  that 
of  l)oiling  water.  Before  using,  always  dip  it  into  water  until  the  hissing  entirely  ceases. 
This  is  one  of  the  most  important  points  in  the  whole  process,  but  one  wh.ich  it  is  very  diffi- 
cult to  make  beginners  properly  appreciate.  The  disadvantages  of  having  too  hot  an  iron 
are  not  apparent  until  an  alter  stage,  while  the  saving  of  time  and  trouble  is  a  great  temp- 
tation to  lieginners. 

A  woll-waxed  sheet  of  paper,  when  viewed  by  obliquely  reflected  light,  ought  to  present 
a  perfectly  uniform  glazed  appearance  on  one  side,  wh.ilo  th  >  other  should  be  rather  duller ; 
there  must  he  no  shining  patches  on  any  part  of  the  siir  ac,  nor  should  any  irregularities 
be  observed  on  examining  the  paper  with  a  black  ground  placed  behind  ;  seen  by  transmit- 


PHOTOGRAPHY.  925 

ted  light,  it  will  appear  opalescent,  but  there  should  be  no  approach  to  a  granular  structure. 
The  color  of  a  pile  of  waxed  sheets  is  slightl}'  bluish. 

The  paper,  having  undergone  this  preparatory  operation,  is  ready  for  iodizing ;  this  is 
effected  by  completely  immersing  it  in  an  aqueous  solution  of  an  alkaline  iodide,  either  pure 
or  mixed  with  some  analogous  salt. 

Bromide  of  potassium  is  sometimes  added,  and  with  much  advantage  in  many  cases,  to 
the  iodizing  bath.  The  addition  of  a  chloride  has  been  found  to  produce  a  somewhat  simi- 
lar effect  to  that  of  a  bromide,  but  in  a  less  marked  degree.  No  particular  advantage,  how- 
ever, can  be  traced  to  it. 

The  best  results  are  obtained  when  the  iodide  and  bromide  are  mixed  in  the  proportion 
of  their  atomic  weights,  the  strength  being  as  follows  : — 

Iodide  of  potassium 582"o  grains. 

Bromide  of  potassium 417 '5  grains. 

Distilled  water       -.-' 40  ounces. 

When  the  two  salts  have  dissolved  in  the  water,  the  mixture  should  be  filtered  ;  the  bath 
will  then  be  fit  for  use. 

At  first  a  slight  difficulty  will  be  felt  in  immersing  the  waxed  sheets  in  the  liquid  with- 
out enclosing  air-bubbles,  the  greasy  nature  of  the  surface  causing  the  solution  to  run  off. 
The  best  jvay  is  to  hold  the  paper  by  one  end,  and  gradually  to  bring  it  down  on  to  the 
liquid,  commencing  at  the  other  end  ;  the  paper  ought  not  to  slant  toward  the  surface  of 
the  bath,  or  there  will  be  danger  of  enclosing  air-bubbles  ;  but  while  it  is  being  laid  down, 
the  part  out  of  the  liquid  should  be  kept  as  nearly  as  possible  perpendicular  to  the  surface 
of  the  liquid  ;  any  curling  up  of  the  sheet  when  first  laid  down  may  be  prevented  by  breath- 
ing on  it  gently.  In  about  ten  minutes  the  sheet  ought  to  be  lifted  up  by  one  corner,  and 
turned  over  in  the  same  manner ;  a  slight  agitation  of  the  dish  will  then  throw  the  liquid 
entirely  over  that  sheet,  and  another  can  be  treated  in  like  manner. 

These  sheets  must  remain  soaking  in  this  bath  for  about  three  hours  ;  several  times  dur- 
ing that  interval  (and  especially  if  there  be  many  sheets  in  the  same  batli)  they  ought  to  be 
moved  about  and  turned  over  singly,  to  allow  of  the  liquid  penetrating  between  them,  and 
coming  perfectly  in  contact  with  every  part  of  the  surface.  After  they  have  soaked  for  a 
sufficient  time,  the  sheets  should  be  taken  out  and  hung  up  to  dry ;  this  is  conveniently 
effected  by  stretching  a  string  across  the  room,  and  hooking  the  papers  on  to  this  by  means 
of  a  pin  bent  into  the  shape  of  the  letter  S.  After  a  sheet  has  been  hung  ujj  for  a  few  min- 
utes, a  piece  of  blotting-paper,  about  one  inch  square,  should  be  stuck  to  the  bottom  corner 
to  absorb  the  drop,  and  prevent  its  drying  on  the  sheet,  or  it  would  cause  a  stain  in  the 
j)icture. 

While  the  sheets  are  drying,  they  should  be  looked  at  occasionally,  and  the  way  in  which 
the  liquid  on  the  surface  dries  noticed  ;  if  it  collect  in  drops  all  over  the  surface,  it  is  a  sign 
that  the  sheets  have  not  been  sufficiently  acted  on  by  the  iodizing  bath,  owing  to  their  hav- 
ing been  removed  from  the  latter  too  soon.  The  sheets  will  usually  during  drying  assume  a 
dirty  pink  appearance,  owing  probably  to  the  liberation  of  iodine  by  ozone  in  the  air,  and 
its  subsequent  combination  with  the  starch  and  wax  in  the  paper.  This  is  by  no  means  a 
bad  sign,  if  the  color  be  at  all  uniform  ;  but  if  it  appear  in  patches  and  spots,  it  shows  that 
there  has  been  some  irregular  absorption  of  the  wax,  or  defect  in  the  iodizing,  and  it  will 
be  as  well  to  reject  sheets  so  marked. 

As  soon  as  the  sheets  are  quite  dry,  they  can  be  put  aside  in  a  box  for  use  at  a  future 
time.  There  is  a  great  deal  of  uncertainty  as  regards  the  length  of  time  the  sheets  may  be 
kept  in  this  state  without  spoiling.  Mr.  Crookes  speaks  from  experience  as  to  there  being 
no  sensible  deterioration  after  a  lapse  of  ten  months. 

Up  to  this  stage,  it  is  immaterial  whether  the  operations  have  been  performed  by  day- 
light or  not ;  but  the  subsequent  treatment,  until  the  fixing  of  the  picture,  must  be  done  by 
yellow  light. 

The  next  step  consists  in  rendering  the  iodized  paper  sensitive  to  light.  Although,  when 
extreme  care  is  taken  in  this  operation,  it  is  hardly  of  any  consequence  when  this  is  per- 
formed ;  yet,  in  practice,  it  will  not  be  found  convenient  to  excite  the  paper  earlier  than 
about  a  fortnight  before  its  being  required  for  use.  The  materials  for  the  exciting  bath  arc 
nitrate  of  silver,  glacial  acetic  acid,  and  water. 

The  following  bath  is  recommended  : — 

Nitrate  of  silver 300  grains. 

Glacial  acetic  acid -         -         2  drachms. 

Distilled  water 20  ounces 

The  nitrate  of  silver  and  acetic  acid  are  to  be  added  to  the  water,  and  when  dissolvcfl, 
filtered  into  a  clean  dish,  taking  care  that  the  bottom  of  the  di.sh  be  flat,  and  that  the  liquid 
cover  it  to  the  depth  of  at  least  half  an  inch  all  over ;  by  the  side  of  this,  two  similar  dishes 
must  be  placed,  each  containing  distilled  water. 

A  sheet  of  iodized  paper  is  to  be  taken  by  one  end,  and  gradually  lowered,  the  marked 


926  PHOTOGRAPHY. 

side  downward,  on  to  the  exciting  solution,  taking  care  that  no  liquid  gets  on  to  the  back, 
and  no  air-bubbles  are  enclosed. 

It  will  be  necessary  for  the  sheet  to  remain  on  this  bath  from  five  to  ten  minutes ;  but  it 
can  generally  be  known  when  the  operation  is  completed  by  the  change  in  appearance,  the 
yink  color  entirely  disappearing,  and  the  sheet  assuming  a  pure  homogeneous  straw  color. 
AV'hen  this  is  the  case,  one  corner  of  it  must  be  raised  up  by  tlse  platinum  spatula,  lifted  out 
of  the  dish  with  rather  a  quick  movement,  allowed  to  drain  for  about  half  a  minute,  and 
then  floated  on  the  surface  of  the  water  in  the  second  dish,  while  another  iodized  sheet  is 
placed  on  the  nitrate  of  silver  solution  ;  when  this  1  as  remained  on  for  a  suflicient  time  it 
must  be  in  like  manner  transferred  to  the  dish  of  distilled  water,  having  removed  the  pre- 
vious sheet  to  the  next  dish. 

A  third  iodized  sheet  can  now  be  excited,  and  when  this  is  completed,  the  one  first  ex- 
cited must  be  rubbed  pei-fectly  dry  between  folds  of  clean  blotting-paper,  wrapped  up  in 
clean  paper,  and  preserved  in  a  portfolio  until  required  for  use ;  and  the  others  can  be 
transferred  a  dish  forward,  as  before,  tidcing  care  that  each  sheet  be  washed  twice  in  dis- 
tilled water,  and  that  at  every  fourth  sheet  the  dishes  of  washing  water  be  emptied  and  re- 
I)Icnished  with  clean  distilled  water ;  this  water  should  not  be  thrown  away,  but  preserved 
in  a  bottle  for  a  subsequent  operation. 

The  above  quantity  of  the  exciting  bath  will  be  found  quite  enough  to  excite  about  fifty 
sheets  of  the  size  here  employed,  or  3,000  square  inches  of  [i.-ijier. 

Of  course  these  sensitive  sheets  must  be  kept  in  perfect  darlcness.  Generally,  sufficient 
attention  is  not  paid  to  this  point.  It  should  be  Ijorne  in  mind,  that  an  amount  of  white 
light,  f[uitc  harmless  if  the  paper  were  only  exposed  to  its  action  for  a  few  minutes,  will 
intallibly  destroy  it  if  it  be  allowed  to  have  access  to  it  for  any  length  of  time  ;  therefore, 
the  longer  the  sheets  are  required  to  be  kept,  the  more  carefully  must  the  light,  even  from 
gas,  be  excluded  ;  they  must  likewise  be  kept  away  from  any  fumes  or  vapor. 

Experience  alone  can  tell  the  proper  time  to  expose  the  sensitive  paper  to  the  action  of 
light,  in  order  to  obtain  the  best  effects.  However,  it  will  be  useful  to  remember,  that  it  is 
almost  always  possible,  however  short  the  time  of  exposure,  to  obtain  some  trace  of  effect 
by  prolonged  development.  Varying  the  time  of  exposure,  within  certain  limits,  makes 
very  little  difference  on  the  finished  picture  ;  its  principal  effect  being  to  shorten  or  prolong 
the  time  of  development. 

Unless  the  exposure  to  light  has  been  extremely  long,  (much  longer  than  can  take  place 
under  the  circumstances  we  are  contemplating,)  nothing  will  be  visible  on  the  sheet  after  its 
removal  from  the  instrument  more  than  there  was  previous  to  exposure  ;  the  action  of  the 
light  merely  producing  a  latent  impression,  which  requires  to  be  developed  to  render  it 
visible. 

The  developing  solution  in  nearly  every  case  consists  of  an  aqueous  solution  of  gallic 
acid,  with  the  addition,  more  or  less,  of  a  solution  of  nitrate  of  silver. 

An  improvement  on  the  ordinary  method  of  developing  with  gallic  acid,  formed  tlie 
subject  of  a  communication  from  Mr.  Crookes  to  the  F/iilosop/iical  Mafjaziite  for  March, 
1855,  who  recommends  the  employment  of  a  strong  alcoholic  solution  of  gallic  acid,  to  lie 
diluted  with  water  when  required  for  use,  as  being  more  economical  both  of  time  and 
trouble  than  the  preparation  of  a  great  quantity  of  an  aqueous  solution  for  each  operation. 

The  solution  is  tints  made  :  Put  two  ounces  of  crystallized  gallic  acid  into  a  dry  flafk 
with  a  narrow  neck  ;  over  this  pour  six  ounces  of  good  alcohol,  (00°  over  jiroof,)  and  place 
the  flask  in  hot  water  until  the  acid  is  dissolved,  or  nearly  so.  This  will  not  take  long,  espe- 
cially if  it  be  well  shaken  once  or  twice.  Allow  it  to  cool,  then  add  half  a  drachm  of  gla- 
cial acetic  acid,  and  filter  the  whole  into  a  stoppered  bottle. 

The  developing  solution  for  one  set  of  sheets,  or  180  square  inches,  is  prepared  by  mix- 
ing together  ten  ounces  of  the  water  that  has  been  previously  used  for  washing  the  excited 
papers,  and  -i  drachms  of  the  exhausted  exciting  bath  ;  the  mixture  is  then  filtered  into  a 
peifeedy  clean  dish,  and  half  a  drachm  of  the  above  ahoholie  solution  of  gallic  acid  poured 
into  it.  The  dish  must  be  shaken  about  until  the  greasy  appearance  is  quite  gone  from  the 
surface  •,  and  then  the  sheets  of  paper  may  be  laid  down  on  the  solution  in  the  ordinary 
manner  with  the  marked  side  downward,  taking  particular  care  that  none  of  the  solution 
gets  on  the  back  of  the  paper,  or  it  will  cause  a  stain.  Should  this  happen,  cither  dry  it 
with  blotting-paper,  or  iumierse  the  sheet  entirely  in  the  liquid. 

If  the  paper  has  been  exposed  to  a  moderate  light,  the  picture  will  begin  to  appear 
within  five  minutes  of  its  being  laid  on  the  sohition,  and  will  be  finished  in  a  few  hours.  It 
may,  however,  sometimes  be  requisite,  if  the  light  has  been  feeble,  to  prolong  the  develop- 
ment for  a  day  or  more.  If  the  dish  be  perfectly  clean,  the  developing  solution  will  remain 
active  for  the  whole  of  this  time,  and  when  used  only  for  a  few  hours,  will  he  quite  clear 
and  colorless,  or  with  the  faintest  tinge  of  brown  ;  a  darker  appearance  indicates  the  pres- 
ence of  dirt.  The  progress  of  the  development  may  be  watched,  by  gently  raising  one  cor- 
ner with  the  platinum  spatula,  and  lifting  the  sheet  up  by  the  finger.*;.  This  should  not  be 
done  too  often,  as  there  is  always  a  risk  of  producing  stains  on  the  surface  of  the  picture. 


PHOTOGEAPHT-  _  927 

As  soon  as  the  picture  is  judged  to  be  sufficiently  intense,  it  must  be  removed  from  the 
gallo-nitrate,  and  hiid  on  a  dish  of  water,  (not  necessarily  distilled.)  In  this  state  it  may 
remain  until  the  final  operation  of  fixing,  which  need  not  be  })erformed  immediately,  if  in- 
convenient. After  being  washed  once  or  twice,  and  dried  between  clean  blotting-paper,  the 
picture  will  remain  unharmed  for  weeks,  if  kept  in  a  dark  place. 

Some  general  remarks  on  Ihe  fixing  processes  will  be  found  toward  the  end  of  this 
article. 

The  Collodion  Process. 

The  difficulty  with  which  we  are  met  in  any  attempt  to  describe  this  photographic  process 
is,  that  it  is  almost  hopeless  to  find  two  photographers  who  adopt  precisely  the  same  order 
of  manipulation  ;  and  books  almost  without  number  have  been  pubhshed,  each  one  recom- 
mending some  special  system. 

By  general  consent  "the  discovery  of  the  collodion  process,  as  now  employed,  is  given  to 
the  late  Mr.  Scott  Archer.  It  will,  therefore,  be  considered  quite  sufficient  to  give  the 
details  of  his  process,  which  has  really  been  but  little  improved  on  since  its  first  intro- 
duction. 

To  prepare  the  collodion. — Thirty  grains  of  gun-cotton  should  be  taken  and  placed  in  18 
fluid  ounces  of  rectified  sulphuric  ether,  and  then  2  ounces  of  alcohol  should  be  added, 
making  thus  one  imperial  pint  of  the  solution.  The  cotton,  if  properly  made,  will  dissolve 
entirely ;  but  any  small  fibre  which  may  be  floating  about  should  be  allowed  to  deposit,  and 
the  clear  solution  poured  off. 

To  iodize  the  collodion. — Prepare  a  saturated  solution  of  iodide  of  potassium  in  alcohol 
— say  one  ounce — and  add  to  it  as  much  iodide  of  silver,  recently  precipitated  and  well 
washed,  as  it  will  take  up :  this  solution  is  to  be  added  to  the  collodion,  the  quantity  de- 
pending on  the  proportion  of  alcohol  which  has  been  used  in  the  preparation  of  the  col- 
lodion. 

Coating  the  plate. — A  plate  of  perfectly  smooth  glass,  free  from  air-bubble  or  stria?, 
should  be  cleaned  very  perfectly  with  a  few  drops  of  ammonia  on  cotton,  and  then  wiped 
in  a  very  clean  cotton  cloth. 

The  plate  must  be  he'd  by  the  left  hand  perfectly  horizontal,  and  then  with  the  right  a 
sufficient  quantity  of  iodized  collodion  should  be  poured  into  the  centre,  so  as  to  diffuse 
itself  equally  over  the  surface.  This  should  be  done  coolly  and  steadily,  allowing  it  to  flow 
to  each  corner  in  succession,  taking  care  that  the  edges  are  well  covered  ;  then  gently  tilt 
the  plate,  that  the  superfluous  fluid  may  return  to  the  bottle  from  the  opposite  corner  to 
that  by  which  the  plate  is  held.  At  this  moment  the  plate  should  be  brought  into  a  vertical 
position,  when  the  diagonal  lines  caused  by  the  fluid  running  to  the  corner  will  fall  one  into 
the  other,  and  give  a  clear  flat  surface.  To  do  this  neatly  and  cfFcctuully,  some  little  prac- 
tice is  necessary,  as  in  most  things  ;  but  the  operator  should  by  no  means  hurry  the  opera- 
tion, but  do  it  systematically,  at  the  same  time  not  being  longer  over  it  than  is  actuallv 
necessary,  for  collodion,  being  an  ethereal  compound,  evaporates  rapidly.  Many  operators 
waste  their  collodion  by  imagining  it  is  necessary  to  perform  this  operation  in  great  haste  ; 
but  such  is  not  the  case,  for  an  even  coating  can  seldom  be  obtained  if  the  fluid  is  poured 
on  and  off  again  too  rapidly ;  it  is  better  to  do  it  steadily,  and  submit  to  a  small  loss  from 
evaporation.  If  the  collodion  becomes  too  thick,  thin  it  with  the  addition  of  a  little  fresh 
and  good  ether. 

Exciting  the  plate. — Previous  to  the  last  operation  it  is  necessary  to  have  the  bath  ready, 
which  is  made  as  follows  : — 

Nitrate  of  silver         -----...30  grains. 

Distilled  water 1  ounce. 

Dissolve  and  filter. 
The  quantity  of  this  fluid  nccessari/  to  be  made  must  depend  upon  the  fo)in  of  trough 
to  he  used,  whether  horizontal  or  vertical,  and  also  upon  the  size  of  the  plate.  With  the 
vertical  trough  a  glass  dipper  is  provided,  upon  which  the  plate  rests,  preventing  the  necos- 
.  sity  of  any  handle  or  the  fingers  going  into  the  liciuid.  If,  however,  the  glass  used  is  a  little 
larger  than  required,  this  is  not  necessary.  Having  then  obtained  one  or  other  of  these  two, 
and  filtered  the  liquid  previously,  the  pfate,  free  from  any  particle  of  dust,  &c.,  is  to  be  /)«- 
niersed  uteadilu  and  without  hesitation ;  for  if  a  jiause  should  be  made  in  any  part,  a  line  is 
sure  to  be  formed,  which  will  print  in  a  subsefiuent  part  of  the  process. 

The  plate  being  immersed  in  the  solution  must  he  kept  there  a  sufficient  time  for  the 
liquid  to  act  freely  upon  the  surface,  particularly  if  a  ncgitivo  picture  is  to  be  obtained. 
As  a  general  ride,  it  u'ill  lake  about  two  mintitrs,  but  (his  will  ran/  iiith  (he  trnifierati/re  of 
the  air  at  ihn  time  of  operating,  and  the  condition  of  the  collodion.  In  cold  weather,  or, 
indeed,  any  thing  below  50°  F.,  the  bath  should  be  placed  in  a  warm  situation,  or  a  proper 
decomposition  is  not  obtained  under  a  very  long  time.  Above  Oi>°  the  plate  will  be  eert:iin 
to  have  obtained  its  maximum  of  sensii)ility  by  two  minutes'  immersion,  but  below  this  tem- 
perature it  is  better  to  give  a  little  extra  time. 


928 


PHOTOGRAPHY. 


To  facilitate  the  action,  let  the  temperature  be  what  it  mav,  the  plate  must  be  lifted  out 
of  the  liquid  two  or  three  times,  which  also  assists  in  getting  rid  of  the  ether  from  the  sur- 
face, for  without  this  is  thoroughly  done,  a  uniform  coating  cannot  be  obtained  ;  but  on 
no  account  should  it  be  removed  unlil  the  plate  lias  bceii  immersed  about  half  a  mijiule,  as 
marks  are  apt  to  be  produced  if  removed  sooner. 

The  plate  is  now  ready  to  receive  its  impression  in  the  camera  obscura.  This  having 
been  done,  the  picture  is  to  be  developed. 

The  development  of  Imar/e. — To  eli'ect  this,  the  plate  must  be  taken  again  into  the  dark 
room,  and  with  care  removed  from  the  slide  to  the  levelling  stand. 

It  will  be  well  to  caution  the  operator  respecting  the  removal  of  the  plate.  Glass,  as 
before  observed,  is  a  bud  conductor  of  heat ;  therefore,  if  in  taking  it  out,  we  allow  it  to  rest 
on  the  fingers  at  any  one  spot  too  long,  that  portion  will  be  warmed  through  to  the  face, 
and  as  this  is  not  done  until  the  developing  solution  is  ready  to  go  over,  the  action  will  be 
more  energetic  at  those  parts  than  at  others,  and  consequently  destroy  tlie  evenness  of  the 
picture.  We  should,  therefore,  handle  the  plate  with  care,  as  if  it  already  possessed  too 
much  heat  to  be  comfortable  to  the  fingers,  and  that  we  must  therefore  get  it  on  the  stand 
as  soon  as  possible. 

Having  then  got  it  there,  we  must  next  cover  the  face  with  the  developing  solution. 

This  should  be  made  as  ibllows  : — 

Pyrogallic  acid 5  grains. 

Glacial  acetic  acid 40  minims. 

Distilled  water 10  ounces. 

Dissolve  and  filter. 

Mr.  Delamotte  employs 

Pyrogallic  acid  -.--•-.--9  grains. 

Glacial  acetic  acid 2  drachms. 

Distilled  water  -.----..-3  ounces. 

Now,  in  developing  a  plate,  the  quantity  of  liquid  taken  must  be  in  proportion  to  its 
size.  A  p'.ate  measuring  5  inches  by  4  will  require  half  an  ounce  ;  less  may  be  used,  but 
it  is  at  the  risk  of  stains ;  therefore  we  would  recommend  that  half  an  ounce  of  the  above 
be  measured  out,  into  a  perfecth/  clean  measure^  and  to  this  from  8  to  12  drops  of  a  50- 
grain  solution  of  nitrate  of  silver  be  added. 

Pour  this  quickly  over  the  surface,  taking  care  not  to  hold  the  measure  too  high,  and 
not  to  pour  all  on  one  spot,  but  having  taken  the  measure  properly  in  the  fingers,  begin  at 
one  end,  and  carry  the  hand  forward  ;  immediately  blow  upon  the  face  of  the  plate,  which 
has  the  effect  not  only  of  diffusing  it  over  the  surface,  but  causes  the  solution  to  combine 
more  ccjually  with  the  damp  surface  of  the  plate  :  it  also  has  the  effect  of  keeping  any  de- 
posit that  may  form  in  motion,  which,  if  allowed  to  settle,  causes  the  picture  to  come  out 
mottled.  A  piece  of  white  paper  may  now  be  held  under  the  plate,  to  observe  the  develop- 
ment of  the  picture  :  if  the  light  of  the  room  is  adapted  for  viewing  it  in  this  manner,  well ; 
if  not,  a  light  must  be  held  below,  but  in  either  case  arrangements  should  be  made  to  view 
the  plate  easily  whilst  under  the  operation :  a  successful  result  depending  so  much  upon 
obtaining  sufficient  development  without  carrying  it  too  fiir. 

As  soon  as  the  necessary  development  has  been  olitained,  the  liquor  must  be  poured  off, 
and  the  surface  washed  with  a  little  water,  which  is  easily  done  by  holding  the  plate  over  a 
dish,  and  pouring  water  on  it ;  talcing  care,  both  in  this  and  a  subsequent  part  of  the  pro- 
cess, to  hold  the  plate  horizontally,  and  not  vertically,  so  as  to  prevent  the  coating  being 
torn  by  the  force  and  weight  of  water. 

Protosulphate  of  iron,  which  was  first  introduced  as  a  photographic  agent  in  1840  by 
Robert  Hunt,  may  be  employed  instead  of  the  pyrogallic  acid  with  much  advantage.  The 
beautiful  collodion  portraits  obtained  by  Mr.  Tunny  of  Edinburgh  are  all  developed  by  the 
iron  salt.     The  following  are  the  best  proportions  : — 

Protosulphate  of  iron -         -         -     1  ounce. 

Acetic  acid 12  minims. 

Distilled  water 1  pint. 

This  is  used  in  the  same  manner  as  the  former  solutions. 

Fixinrj  of  imnfie. — This  is  simply  the  removal  of  iodide  of  silver  from  the  surface  of  the 
plate,  and  is  effected  l)y  pouring  over  it,  after  it  has  been  dipped  into  water,  a  solution  of 
hyposulphite  of  soda,  made  of  the  strength  of  4  ounces  to  a  pint  of  water.  At  this  point 
dayliglit  may  be  admitted  into  the  room,  and,  indeed,  we  cannot  judge  well  of  its  removal 
without  it.  We  then  see  by  tilting  the  plate  to  and  fro  the  iodide  gradually  dissolve  away, 
and  the  different  parts  left  more  or  less  transparent,  according  to  the  action  of  light  upon 
them. 

It  then  only  remains  to  thoroughly  wash  away  every  trace  of  the  hyposulphite  of  soda, 
for  should  any  salt  be  left,  it  gi'adually  destroys  the  picture.  The  plate  should  therefore 
cither  be  immersed  with  great  care  in  a  vessel  of  clean  water ;  or,  what  is  better,  water 


PLUMBAGO.  929 

poured  gently  and  carefully  over  the  surface.  After  this  it  must  be  placed  upright  to  dry, 
or  held  before  a  fire. 

Tke  fixing  proce^es.  The  most  important  part  of  Photography,  and  one  to  which  the 
least  attention  has  been  paid,  is  the  process  of  rendering  permanent  the  beautiful  images 
which  have  been  obtained.  Nearly  all  the  fine  photogiaplis  with  which  we  are  now  familiar 
are  not  permanent.  This  is  deeply  to  be  regretted,  especially  as  there  appears  to  be  no  ne- 
cessity for  their  fading  away.  In  nearly  all  cases  the  fading  of  a  photograph  may  be  re- 
ferred to  carelessness,  and  it  is  not  a  little  startling,  and  certainly  very  annoying,  to  hear  a 
very  large  dealer  in  photographic  pictures  declare  that  the  finest  pictures  by  the  best  pho- 
tographers are  the  first  to  fade.  This  is,  no  doul)t,  to  be  accounted  for  by  the  demand  which 
there  is  for  their  pictures,  leading  to  a  fatal  rapidity  in  the  necessary  manipulatory  details. 

There  is  no  necessity  for  a  photograph  to  fade  if  kept  with  ordinary  care.  It  should  be 
at  all  events  as  permanent  as  a  sepia  drawing.  The  hyposulphite  of  soda  is  the  true  fixing 
agent  for  any  of  the  photographic  processes,  be  they  Daguerreotype,  calotype,  collodion,  or 
the  ordinary  process  for  producing  positive  prints.  It  should  be  understood,  whichever  of 
t!ie  salts  of  silver  are  employed,  that  by  the  action  of  the  solar  rays  either  oxide  of  silver 
or  metallic  silver  is  produced,  and  the  unchanged  chloride,  iodide,  or  bromide  can  be  dis- 
solved out  by  the  use  of  the  hyposulphite  of  soda. 

The  photographic  picture  on  paper,  on  metal,  or  on  glass,  is  washed  with  a  strong  solu- 
tion of  the  hyposulphite  of  soda,  and  the  silver  salt  employed  combines  with  it,  forming  a 
peculiarly  sweet  compound,  the  hyposulphite  of  silver ;  this  is  .soluble  in  water,  and  hence 
we  have  only  to  remove  it  by  copious  ablutions.  The  usual  practice  is  to  place  the  pictures 
in  trays  of  water  and  to  change  the  fluid  frequently.  In  this  is  the  danger,  and  to  it  may 
be  traced  the  fading  of  nine-tenths  of  the  pictures  prepared  on  paper. 

Paper  is  a  mass  of  linen  or  cotton  fibre  ;  howsoever  fine  the  pulp  may  be  prepared,  it 
is  still  full  of  capillary  pores,  which,  by  virtue  of  the  force  called  capiliarity,  hold  with 
enormous  force  a  large  portion  of  the  solid  contents  of  the  water.  If  we  make  a  solution 
of  a  known  strength  of  the  hyposulphite  of  soda,  and  dip  a  piece  of  paper  into  it,  it  will 
be  found  to  have  lost  more  of  the  salt  than  belongs  to  the  small  quantity  of  water  abstract- 
ed by  the  paper.  Solid  matter  in  excess  has  been  withdrawn  from  the  solution.  So  a  pho- 
togaphic  picture  on  paper  holds  with  great  tenacity  one  or  other  of  the  hyposulphites.  By 
soaking  there  is  of  course  a  certain  portion  removed,  but  it  is  not  possible  by  any  system 
of  soaking  to  remove  it  all. 

The  picture  is,  however,  prepared  in  this  manner,  and  slowly,  but  surely,  under  the  com- 
bined influences  of  the  solar  rays  and  atmospheric  moisture,  the  metallic  silver  loses  color, 
i.  e.,  the  photograph  fodes. 

Tiie  only  process  to  be  relied  on  demands  that  every  picture  should  be  treated  sepa- 
rately. First,  any  number  may  be  soaked  in  water,  and  the  water  changed  ;  by  this  means 
the  excess  of  the  hyposulphite  of  silver  is  removed.  Then  each  picture  must  be  taken  out 
and  placed  upon  a  slab  of  porcelain  or  glass,  and  being  fixed  at  a  small  angle,  water  should 
be  allowed  to  flow  freely  over  and  off  it.  Beyond  this,  the  operator  should  be  furnished 
with  a  piece  of  soft  sponge,  and  he  should  maintain  for  a  long  time  a  dabbing  motion.  By 
this  mechjmical  means  he  disturbs  the  solid  matter  held  in  the  capillary  tubes,  and  eventu- 
ally removes  it.  The  labor  thus  bestowed  is  rewarded  by  the  production  of  a  permanent 
picture,  not  to  be  secured  by  any  other  means. 

In  this  article  those  processes  only  which  have  become  of  commercial  value  have  been 
noted.  The  Carbon  process  of  printing,  which  promises  well,  can  scarcely  be  said  to  be  as 
yet  in  a  perfect  state  ;  and  for  the  other  curious  but  less  important  processes,  and  for  a  full 
examination  of  the  philosophv  of  the  subject,  see  Hunt's  Jicsearches  on  Lic/hl,  2d  edition. 

PLATIXUM,  ALLOYS  OF.  This  metal  will  alloy  with  iron ;  the  alloy  is  malleable, 
and  possesses  much  lustre. 

Copper  and  platinum  in  certain  proportions  form  a  brilliant  alloy. 

Silver  is  much  hardened  by  platinum  ;  although  platinum  is  not  soluble  in  nitric  acid,  it 
will,  when  alloyed  with  silver,  dissolve  in  that  acid. 

Some  other  alloys  are  known,  but  none  of  them  are  employed. 

PLUMBAGO,  commonly  called  Black  Lkad  ;  the  name  plumbago,  and  its  common 
one,  being  derived  from  the  fact  of  this  mineral  resembling  lead  in  it?  exernal  appearance. 
In  this  country  plumbago  has  been  found  most  abundantly  in  Cumberland.  The  mountain 
at  Borrowdale,  in  which  the  black  lead  is  mined,  is  nearly  2,000  feet  high,  and  the  entrance 
to  the  mine  is  about  1,000  feet  below  its  summit.  This  valuable  mineral  became  so  com- 
mon a  subject  of  robbery  about  a  century  ago,  as  to  have  enriched,  it  was  said,  a  great 
many  persons  living  in  the  neighborhood.  Even  tlie  guard  stationed  over  it  by  the  proprie- 
tors wiia  of  little  avail  against  men  infuriated  with  tlie  love  of  plunder;  since  in  those  days 
a  body  of  miners  broke  into  the  mine  by  main  force,  and  held  possession  of  it  for  a  con- 
siderable time. 

The  treasure  was  then  protected  by  a  building,  consisting  of  four  rooms  upon  the  ground 
floor  ;  and  immediately  under  one  of  them  is  the  opening,  secured  by  a  trap-door,  through 
Vol.  III.— 59 


930  PORCELAIN  CLAY. 

which  alone  workmen  could  enter  the  interior  of  the  mountain.  In  tliis  apartnient,  called 
the  dressing-room,  the  miners  change  their  ordinary  clothes  for  their  mining  dress.  At  one 
time  as  much  as  £100,000  was  realized  from  the  Borrowdale  mine  in  a  year,  the  Cumber- 
land plumbago  selling  at  45s.  per  pound.  This  mine  has  not,  however,  been  worked  for 
many  years.  The  la.-;t  great  discovery,  stated  to  have  been  about  £30,(i00"s  worth,  has  been 
hoarded  by  the  proprietors,  a  small  quantity  only  being  sold  every  year  ;  but  it  is  now  gen- 
erally understood  to  be  nearly  exhausted.  Some  few  years  since  the  Borrowdale  Black 
Lead  Mine  was  inspected  by  three  experienced  miners,  but  their  report  was  far  from  en- 
couraging ;  notwithstanding  which  a  new  company  has  been  recently  (1859)  formed  to  work 
this  mine. 

This  plumbago  in  Borrowdale  is  found  in  "  nests"  in  a  trap  rock,  partially  decomposed, 
which  runs  through  the  clay  slate.  In  Glenstrathfarrar  in  Inverness,  it  is  found  in  gneiss, 
and  at  Craigman  in  Ayrshire  it  occurs  in  coal  beds  which  have  been  iormcd  in  coiitact  with 
trap.  In  Cornwall  plumbago  has  been  discovered  in  small  lumps  in  the  El  van  courses ;  and 
on  the  northern  coast  of  that  country,  small  pieces  are  picked  out  of  the  clay  slate  rocks, 
where  it  has  been  exposed  by  the  wearing  down  of  the  cliffs.  At  Arendal,  in  Norway,  it 
occurs  with  quartz.  Plumbago  is  sometimes  formed  in  considerable  quantities  in  the  beds 
of  blast  furnaces,  especially  at  Cleator  Moor. 

Plumbago  occurs  in  Finland.  Large  quantities  are  brought  from  Ceylon  and  the  East 
Indies.     Some  considerable  portions  are  obtained  from  the  mines  of  the  United  States. 

Mr.  Brodie  purifies  plumbago  by  mixing  it  in  coarse  powder,  in  an  iron  vessel,  with 
twice  its  own  weight  of  commercial  sulphuric  acid,  and  seven  per  cent,  of  chlorate  of  pot- 
ash, and  heats  the  whole  over  a  water  bath  until  chloric  oxide  ceases  to  be  evolved.  By 
this  means  the  compounds  of  iron,  lime,  and  alumina  present,  are  rendered  for  the  most 
part  soluble,  and  the  suljsequcnt  addition  of  a  little  fluoride  of  sodium  to  the  acid  mixture, 
will  decompose  any  silicates  which  may  remain,  and  volatilize  the  silica  present.  The  mass 
is  now  washed  with  abundance  of  water,  dried,  and  heated  to  redness.  This  last  operation 
causes  the  grains  of  the  plumbago  to  exfoliate.  The  mass  swells  up  in  a  surprising  man- 
ner, and  is  reduced  to  a  state  of  very  minute  division.  It  is  then  levigated,  and  obtained 
in  a  state  of  great  purity,  ready  to  be  compressed  by  the  method  of  Brockedon. — T.  S.  H. 

POAKE.  A  name  amongst  peltmongers  for  the  collected  waste  arising  in  the  prepara- 
tion of  skins  ;  it  is  used  for  manure. 

PORCELAIN'  CLAY.  {Kaolin.)  Nature  has,  up  to  a  certain  point,  provided  the  arti- 
cle which  man  requires  for  the  elaboration  of  the  most  perfect  production  of  the  potter  s 
art.  The  clay — China  clay,  a.s  it  is  commonly  called,  or  kaolin,  as  the  Chinese  have  it — is 
quarried  from  amidst  the  granitic  masses  of  Dartmoor  and  of  Cornwall.  We  are  not  at  all 
satisfied  with  any  of  the  theories  which  have  been  put  forward  to  account  for  the  formation 
of  porcelain  clay.  It  is  commonly  stated  to  be  a  decomposed  granite ;  this  rock,  as  is  well 
known,  consisting  of  mica,  quartz,  and  felspar,  with  sometimes  shorl  and  hornblende.  The 
felspar  is  supposed  to  have  decomposed  ;  and,  as  this  forms  the  largest  portion  of  the  mass, 
the  granite  is  disintegrated  by  this  process.  We  have,  therefore,  the  mica,  quartz,  and  the 
clay,  forming  together  a  soft  mass,  lying  but  a  short  distance  below  the  surface,  but  extend- 
ing to  a  fconsiderable  depth.  It  is  quite  evident  that  this  stratum  is  not  df posited ;  had  it 
been  so,  the  particles  constituting  the  mass  would  have  arranged  themselves  in  obedience 
to  the  law  of  gravity,  towards  which  there  is  not  the  slighest  attempt.  But  we  do  not  know 
by  what  process  the  decomposition  of  the  solid  granite  could  have  been  effected  to  a  depth 
from  the  surface  of  upwards  of  one  hundred  feet,  and  then,  as  it  often  does,  suddenly  to 
cease.  This,  however,  is  a  question  into  which  we  cannot  at  present  enter.  The  largest 
quantity  of  porcelain  or  China  clay  is  manufactured  in  Cornwall,  especially  about  St.  Austell 
and  St.  Stephens;  from  which,  in  1859,  about  G0,000  tons  were  sent  away  to  the  potteries, 
and  for  paper-making  and  bleaching. 

A  spot  being  discovered  where  this  substance  abounds,  the  operation  is  commenced  by 
removing  the  vegetable  soil  and  substratum,  called  liy  the  workmen  the  oi-erlmrdni,  which 
varies  in  depth  f^i-om  about  three  to  ten  feet.  The  lowest  part  of  the  ground  is  then  select- 
ed, in  order  to  secure  an  outlet  for  the  water  used  in  washing  the  clay.  The  overlurdin 
being  removed,  the  clay  is  dug  up  in  slopes :  that  is,  in  successive  layers  or  courses,  and 
each  one  being  excavated  to  a  greater  extent  than  the  one  immediately  below  it,  the  slopes 
resemble  a  flight  of  irregular  stairs.  The  depth  of  the  china  clai/ pits  is  various,  extending 
from  twenty  feet  to  fifty  feet. 

The  clay  when  first  raised  has  the  appearance  and  consistence  of  mortar;  it  contains 
numerous  grains  of  quartz,  which  are  disseminated  throughout  in  the  same  manner  as  in 
granite.  In  some  parts  the  clay  is  stained  of  a  rusty  color,  from  the  presence  of  veins  and 
imbedded  portions  of  shorl  and  quartz ;  these  are  called  by  the  workmen  irced,  capJe,  and 
shell,  which  are  carefully  separated.  The  clay  is  next  conveyed  to  the  floor  of  the  washing 
place,  and  is  then  ready  for  the  first  operation  of  the  process. 

A  heap  of  the  clay  being  placed  on  an  inclined  platform,  on  which  a  little  stream  of 
water  falls  from  the  height  of  about  six  feet,  the  workman  constantly  moves  it  and  turns  it 


POROELAIX  CLAY. 


931 


over  with  a  piffc/le  and  shovel,  by  which  means  the  whole  is  gradually  carried  down  into  an 
oblong  trench  beneath,  which  is  also  inclined,  and  which  ends  in  a  covei'cd  channel  that 
leads  to  the  catch-pits  about  to  be  described.  In  the  trench  the  giains  of  quartz  are  de- 
posited, but  the  other  parts  of  the  clay,  in  consequence  of  their  greater  levity,  are  carried 
away  in  a  state  of  suspension. 

This  watjr  is  conducted  into  a  series  of  pits,  each  of  which  is  about  eight  feet  long,  four 
in  breadth  and  in  depth,  and  is  lined  on  the  sides  and  bottom  with  cut  nioorstone,  laid  in  a 
waterproof  cement.  In  these  pits  the  porcelain  earth  is  gradually  deposited.  In  the  lir.'^t 
pit  the  grosser  particles  collect  ;  and  being  of  a  mixed  nature,  aie  always  rejected  at  the 
end  of  each  day's  work  by  an  opening  provided  for  that  purpose  at  the  bottom  of  the  pit. 
When  the  water  has  filled  the  first  pit,  it  overflows  into  the  second,  and  in  like  manner  into 
the  third ;  and  in  these  pits,  particularly  in  the  second,  a  deposit  also  takes  place,  which  is 
often  preserved,  and  is  called  by  the  workmen  mica.  The  water,  still  holding  in  suspension 
the  finer  and  purer  particles  of  porcelain  clay,  next  overflows  into  larger  pits,  caWed  ponds:, 
which  are  of  the  same  depth  as  the  first  pits,  but  about  three  times  as  long  and  wide.  Here 
the  clay  is  gradually  deposited,  and  the  clear  supernatant  water  is  from  time  to  time  dis- 
charged by  plug-holes  on  one  side  of  the  pond.  This  process  is  continued  until,  by  succes- 
sive accumulations,  the  ponds  are  filled.  At  this  stage  the  clay  i.s  in  the  state  of  a  thick 
paste  ;  and  to  complete  the  process  it  only  remains  to  be  consolidated  by  drying,  and  then 
it  is  fit  for  the  market. 

This,  however,  is  a  tedious  operation  in  our  damp  climate,  and  is  effected  as  follows  : — 
The  moist  clay  is  removed  in  hand-barrows  into  prtn.s,  wiiich  are  constructed  like  the /re7.s 
and  ponth,  but  are  much  larger,  being  about  forty  feet  long,  fifteen  wide,  and  a  foot 
and  a  half  in  depth.  The  above  dimensions  may  not  be  quite  correct,  for  I  did  not  actually 
measure  the  pits  ;  they  are,  however,  very  near  the  truth.  When  the  pans  are  nearly  filled, 
the  clay  is  levelled,  and  is  then,  allowed  to  remain  undisturbed  until  it  is  nearly  dry.  The 
time  required  for  this  part  of  the  process  must  depend  in  a  great  measure  on  the  state  of 
the  weather  and  the  senson  of  the  year,  because  the  pans  are  exposed  to  the  air.  During 
the  winter  at  least  eight  months  are  necessary,  whilst  during  the  summer  less  than  half  the 
ti.ne  is  sufficient. 

When  the  clay  is  in  a  fit  state,  it  is  cut  into  oblong  masses,  and  carried  to  the  drying 
house — an  oblong  shed,  the  sides  of  which  are  open  wooden  frames,  constructed  in  the 
usual  way  for  keeping  oil'  the  rain,  but  admitting  the  free  passage  of  the  air. 

The  clay  thus  dried  is  next  scraped  perfectly  clean,  and  is  then  packed  up  into  casks, 
and  carried  to  one  of  the  adjacent  ports,  to  be  shipped  for  the  potteries. 

The  porcelain  earth  thus  prepared  is  of  a  beautiful  and  uniform  whiteness,  and  is  perfect- 
ly smootii  and  soft  to  the  touch. — Br.  Boase\  Geologi)  of  Cornwall. 

The  works  at  Lee  Moor,  on  the  borders  of  Dartmoor,  being,  however,  far  more  com- 
plete, we  have  selected  them  as  the  best  for  our  description.    -Seejix/.  5G8. 

568 


Ileie  we  see  a  quarry  of  thi.s  decomposed  granite,  shining  white  in  the  sunshine,  and  at 
tlie  ))ottom  of  thi.s  quarry  are  numerous  workmen  cni[)l()yed  in  filling  trucks  placed  upon  a 


932  POTASH,  NITRATE  OF. 

tramway.  This  native  material  is  now  carried  off  to  a  house,  distinguislied  by  the  powerful 
water-wheel  which  revolves  on  one  side  of  it,  and  here  it  undergoes  its  lirst  process  in 
manufacture.  The  trucks  are  lifted,  and  the  contents  discharged  into  a  hopper,  from  which 
the  clay  falls  into  inclined  troughs,  through  which  a  strong  current  of  water  passes,  and  the 
clay  is  separated  fvom  the  large  particles  of  quartz  and  mica,  these  being  discharged  over  a 
grating,  tlirongh  vliich  flows  the  water  charged  with  the  clay  and  the  finer  matter,  the 
coarser  portion  sliding  off  the  grating,  and  Jailing  in  a  heap  outside  the  building.  The 
water  Contains  not  only  the  pure  clay,  but  the  finer  particles  of  silica,  mica,  shorl,  or  of  any 
other  matters  which  may  be  mixed  with  the  mass.  To  separate  these  from  the  clay,  very 
complete  arrangements  are  made.  Large  and  deep  stone  tanks  receive  the  water  as  it  comes 
from  the  mill ;  in  these  the  heavier  particles  settle  ;  and  when  each  tank  becomes  full,  the 
mica,  &c.,  is  discharged  through  openings  in  the  bottom,  into  trucks  placed  to  receive  it  on 
a  railway,  and  this,  the  refuse  material  of  the  clay  works  elsewhere,  is  liere  preserved  for 
other  uses,  to  be  by-and-by  described.  The  water,  chai-ged  with  its  clay,  now  flows  slowly 
and  quietly  through  a  great  length  of  stone  channel,  and  during  its  progress  nearly  all  the 
micaceous  and  other  particles  subside  ;  the  water  eventually  flowing  into  very  large  pits,  in 
which  the  clay  is  allowed  slowly  to  deposit.  The  water  enters  in  a  thin  sheet  at  one  end, 
and  gradually  diffuses  itself  over  the  large  area.  The  clay,  in  an  impalpable  powder,  falls 
^down,  and  perfectly  clear  water  passes  away  at  the  other  end.  From  the  clay  tanks  marked 
A  and  B  in  the  plan,  the  semi-fluid  clay  is  pumped  into  the  clay-pans,  beneath  which  there 
circulate  hot-water  pipes,  and  in  these  the  clay  is  finally  dried.  When  a  thickness  of  about 
eighteen  inches  is  obtained,  evaporation  is  promoted  by  the  graduated  artificial  temperatm-e 
produced  by  the  water  pipes.  After  a  little  time,  the  clay  is  sufficiently  hard  to  Ije  cut  out, 
and  subjected  to  its  final  drying.  The  clay  is  cut  out  in  squares  of  about  eight  inches,  so 
that  they  form  parallelograms  when  removed  from  the  bed.  These  are  then  placed  in  heat- 
ed rooms,  and  being  still  further  dried,  are  fit  for  the  market. 

POTASH,  XITKATE  OF,  KO,NO^  Syn.  Nitre,  Saltpetre,  Priamatic  nitre.  {Nitrate 
(le  potasse,  Fr. ;  Sa/petersaiires  Kali,  Germ.)  For  the  mode  of  purification,  see  GrxpowDER. 
This  well  known  and  useful  salt  is  found  native  in  various  parts  of  the  world,  more  espe- 
cially in  tropical  climates.  The  formation  of  nitre  in  the  earth  appears  to  be  much 
facilitated  by  warmth. 

Prejmratio7i.  1.  By  lixiviation  of  earth  impregnated  with  the  salt.  The  earth  is  heat- 
ed with  water  in  tanks  or  tubs  with  false  bottoms,  and  after  sufficient  digestion  the  solution 
is  run  off  and  evaporated  to  crystallization.  The  nitre  procured  by  the  first  operation  is 
exceedingly  impure,  and  contains  large  quantities  of  chloride  of  potassium,  and  some 
sulphate  of  potash.  By  repeated  crystallizations  the  salt  may  be  obtained  pure.  If  the 
crude  product  of  the  lixiviatioa  contains,  as  is  often  the  case,  the  nitrates  of  lime  or 
magnesia,  they  may  be  got  rid  of  by  the  addition  of  carbonate  of  potash  ;  the  earths  are  pre- 
cipitated as  carbonates,  and  may  be  filtered  off,  while  an  equivalent  quantity  of  nitrate  of  pot- 
ash is  formed  and  remains  in  solution,  thus : — 

CaO,NO=  -1-  KO,CO^  =  CaO,CO^  +  KO,NO^ 

2.  The  second  mode  of  preparing  nitre  which  we  shall  consider,  is  from  nitrate  of 
soda  and  chloride  of  potassium.  On  dissolving  equivalent  quantities  of  these  two  salts  in 
water,  and  salting  down,  double  decomposition  takes  place.  The  chloride  of  sodium  may 
be  removed  from  the  hot  concentrated  fluid  by  means  of  shovels,  while  the  nitrate  of  potash, 
being  much  more  soluble  in  hot  than  in  cold  water,  remains  in  solution,  but  crystallizes  out 
on  cooling.     The  decomposition  takes  place  in  accordance  with  the  annexed  equation : — 

XaO.XO"  +  KCl  =:  XaCl  +  KO,NO^ 
The  above  reaction  is  one  of  great  interest  and  importance,  inasmuch  as  it  enables  us  to 
convert  Peruvian  or  cubic  nitre,  as  nitrate  of  soda  is  sometimes  called,  into  the  much  more 
valuable  salt,  nitrate  of  potash.  During  the  last  war  with  Eussia  it  was  found  that  large 
quantities  of  chloride  of  pota.ssium  were  exported,  and  found  their  way  into  that  country. 
For  some  time  no  notice  was  taken,  because  the  salt  appeared  too  haiTnless  to  be  declared 
contraband  of  war.  Eventually  it  was  found  that  it  was  entirely  used  in  Russia  for  the 
purpose  of  affording  nitrate  of  potash,  by  the  process  described.  -It  need  scarcely  be  said 
that  the  gunpowder  made  through  the  medium  of  our  own  chloride  of  potassium,  was  em- 
ployed against  our  troops  in  the  Crimea. 

3.  Nitre  may  of  course  be  prepared  by  neutralizing  nitric  acid  by  means  of  carbonate 
of  potash,  or  the  caustic  alkali.  The  process  is  evidently  too  expensive  to  be  employed, 
except  for  the  purpose  of  experimental  illustration,  or  under  other  special  circumstances. 

The  formation  of  nitre  in  the  earth  of  hot  climates  is  probably  in  most  cases  due  to  the 
decomposition  of  nitrogenized  organic  matters.  The  subject  of  nitrification  is  one  upon 
which  some  controversy  has  taken  place.  It  is  supposed  by  some  chemists  that  the  chief 
source  of  the  nitric  acid  is  the  ammonia  produced  during  the  decay  of  nitrogenous  matters. 
The  presence  of  bases  appears  to  have  a  remarkable  tendency  to  increase  the  production  of 
the  acid.     It  has  been  asserted  that  the  ammonia  which  is  produced  suffers  partial  oxidation, 


POTASH,  NITRATE  OF. 


933 


the  acid  formed  uniting  with  undecomposed  ammonia  to  form  the  nitrate  of  that  alkali. 
On  the  other  hand,  it  has  been  argued  that  the  ammonia  does  not  suffer  oxidation,  but  that 
the  nitrogen  produced  during  the  decay  of  organic  matter  combines,  at  tlie  instant  of  its 
liberation  with  oxygen,  to  form  nitric  acid,  which  unites  with  the  bases  present.  Nitrate 
of  ammonia,  no  matter  how  formed,  suffers  double  decomposition  in  presence  of  the  carbo- 
nates of  the  alkaline  earths,  the  result  being  the  production  of  the  nitrates  of  lime  and 
magnesia.  It  is  owing  to  the  presence  of  the  two  latter  salts  in  the  crude  liquor  obtained 
by  lixiviating  nitrified  earth,  that  the  addition  of  carbonate  of  potash  is  so  important,  and 
causes  so  great  an  increase  in  the  produce  of  nitre.  It  has  been  insisted  by  some  observers 
that  the  presence  of  nitrogenous  organic  matters  is  not  essential  to  the  production  of  nitre. 
In  support  of  this  it  has  been  sliown  tliat  large  quantities  of  nitrates  are  often  found  where 
little  or  no  organic  matters  are  present.  This  has  been  explained  by  assuming  tliat  porous 
bodies  have  the  power  of  absorbing  water,  oxygen,  and  nitrogen,  and  producing  nitric  acid 
from  them.  But  it  is  evident  that  other  forces  exist  capable  of  inducing  the  oxidation  of 
atmospheric  nitrogen.  It  has  been  experimentally  demonstrated  that  nitric  acid  is  produced 
during  the  discharge  of  atmospheric  electricity.  It  is  also  probable  that  ozone  plays  an 
important  part  in  the  phenomena  of  nitrification.  Perhaps  the  most  of  the  chemists  who 
have  investigated  the  subject,  have  been  too  anxious  to  assign  the  formation  of  nitre  to  one 
particular  cause,  whereas  the  phenomena  which  have  been  noticed  by  different  observes  are 
in  favor  of  the  idea  tliat  several  agencies  are  at  work  during  the  production  of  nitrates  in 
the  earth  and  in  artificial  nitre  beds. 

During  the  time  that  France  was  fighting  single-handed  against  the  rest  of  Europe, 
great  ditficulty  was  found  in  obtaining  sufficient  nitre  for  the  production  of  the  vast  amount 
of  gunpowder  necessary  to  enable  her  artillery  to  be  effectively  supplied  with  ammunition. 
This  led  the  French  chemists  to  establish  artificial  nitre  beds  in  various  paits  of  the  country. 
The  success  of  the  process  may  be  judged  of  from  the  fact  that  they  yielded  2,000  tons 
annually. 

Chemical  and  phi/sical  jn'opertiex. — Nitre  crystallizes  in  colorless  six-sided  prisms.  The 
crj'stals  are  anhydrous ;  large  specimens,  when  broken,  however,  generally  show  the  pres- 
ence of  a  little  moisture  mechanically  adhering  to  the  interstices.  If  wanted  in  fine 
powder,  it  must  therefore  be  first  coarsely  bruised,  and  then  dried,  after  which  it  may  be 
finely  pulverized  and  sifted,  without  that  tendency  to  adhere  into  lumps  which  would  other- 
wise be  observed. 

By  the  careful  application  of  heat,  nitrate  of  potash  may  be  melted  without  undergoing 
any  decomposition  or  loss  of  weight.  But  if  the  heat  be  raised  to  redness  it  begins  to  de- 
compose, the  degree  to  which  the  change  takes  place  depending  on  the  amount  of  heat  and 
the  time  of  exposure.  By  carefully  heating  for  some  time,  a  large  quantity  of  nitrite  of 
pot.ish  is  formed,  oxj'gen  gas  Ijeing  evolved.  If  the  heat  be  raised,  or  the  exposure  to  a 
high  temperature  be  continued,  a  large  quantity  of  nitrogen  accompanies  the  oxygen,  and 
the  nitre  becomes  more  and  more  changed,  until  finally,  a  mixture  of  potash  with  peroxide 
ofpot;issium  is  attained.  If  copper  filings,  clippings,  or  shreds  be  mixed  with  the  nitre, 
the  decomposition  proceeds  much  more  readily,  and  Wohlcr  has  proposed  to  prepare  pure 
potash  by  this  means.  At  high  temperatures  nitre  is  a  potent  agent  of  oxidation,  so  much 
so,  that  the  diamond  itself  is  attacked  and  converted  into  carbonic  acid,  which  unites  with 
the  potash.  It  was  in  this  manner  that  Smithson  Tennant  first  showed  the  diamond  to 
consist  of  pure  carbon.  Ills  mode  of  operating  was  to  fuse  the  nitre  with  fragments  of 
diamond  in  a  tube  of  gold.  Cry.stallized  boron,  which  is  said  to  equal  if  not  exceed  the 
diamond  in  hardness,  is  not  attacked  by  fused  nitre.  A  very  striking  experiment  lor  the 
lecture  table  consists  in  pouring  charcoal  in  powder  into  melted  nitre  retained  at  a  red  heat 
over  a  lamp.  A  violent  deflagration  takes  place,  and  a  considerable  quantity  of  carbonate 
of  potash  js  formed.  The  presence  of  the  latter  substance  may  be  shown  as  soon  as  the 
capsule  has  become  cold,  l)y  adding  an  acid  to  its  contents,  when  a  strong  effervescence  will 
take  place.  The  oxidizing  power  of  nitre  is  made  use  of  in  the  arts  in  order  to  obtain 
bichromate  of  potash  from  chrome  iron  ore. 

Nitrate  of  potash  is  sometimes  used  as  a  source  of  nitric  acid,  but  nitrate  of  soda  is  in 
every  way  more  economical.  This  will  be  evident  when  it  is  considered  that  it  takes  101 
parts  of  nitrate  of  potash  to  yield  one  equivalent  of  dry  nitric  acid  (.54  parts),  whereas  85 
[tarts  of  nitrate  of  soda  yield  the  same  amount  of  acid.  Moreover,  if  nitrate  of  potash  bo 
used,  it  is  essential  to  employ  two  equivalents  of  sulphuric  acid  to  decompose  one  etjuivalent 
of  the  salt,  for  if  only  one  were  used,  the  residue  of  sulphate  of  potash  being  hard,  and  not 
very  readily  removable  by  water,  considerable  chances  would  be  incurred  of  injuring  the 
still ;  it  is  usual,  therefore,  to  so  adjust  the  proportions  that  the  readily  soluble  bisulphate 
should  be  the  residue.  If,  on  the  other  hand,  nitrate  of  .soda  be  employed,  the  residue  in 
the  still  being  sul[)hate  of  soda,  no  dillicidt.y  is  found  in  its  removal. 

Nitrate  of  potash  is  employed  in  l)low-pipe  experiments,  in  order  to  assist  in  the  pro- 
duction of  the  green  reaction  characteri.stie  of  the  presence  of  manganese.  It  often  happens 
where  the  (juantity  of  manganese  is  exceedingly  small,  as  in  rose  quartz,  that  the  green 


934  rOTASII,  XlTIiATE  OF. 

coloration  with  soda  or  platinum  foil  cannot  be  obtained  ;  if,  however,  a  little  nitre  be  add- 
ed, and  the  testin;^  be  repeated,  the  reaction  trenerally  ai)pears  witliuut  any  trouljle. 

Nitrate  of  pota^li  is  greatly  employed  in  tb.e  prepaiation  of  pyrotechnic  mixtures.     It 
ought  always  to  be  well  dried  and  reduced  to  fine  powder  before  being  used. 
Solubility  of  nitre  in  water  at  various  temperatures. 
1  part  of  nitre  dissolves  in  13'320  parts  of  water  at  32°*0 

"  4-000  "  er-o 

"  3-450  "  64°-4 

"  1-340  "  113"-0 

«•  0-424  "  206''-6 

"  0-250  "  212'-0 

From  the  above  table  it  is  evident  that  the  solubility  of  nitre  in  water  increases  very 
rapidly  with  the  temperature.  Nitre  is  not  unfrequently  employed  by  the  chemist  for 
determining  the  percentage  of  sulphur  in  coals.  For  this  purpose  the  coal,  reduced  to  fine 
powder,  is  mixed  with  nitre  and  carbonate  of  soda,  and  projected  by  small  portions  into  a 
silver  crucible,  maintained  at  a  red  heat.  A  platinum  crucible  must  not  be  employed,  as  it 
is  attacked  by  nitre  in  a  state  of  fusion.  The  sulphur  in  the  coal  is  converted,  by  the  oxidi- 
zing agency  of  the  nitre,  into  sulphuric  acid  ;  the  latter  can  then  be  converted  into  sulphate 
ol'baiyta,  and  the  jiercentage  of  sulphur  ascertained  from  its  weight. 

Extiiiiution  of  the  value  of  nitre. — A  great  number  of  processes  have  been  devised  for 
the  determination  of  the  percentage  of  puie  nitre  of  jjotash  in  samples  of  the  crude  salt. 
All  these  processes  are  more  or  less  incorrect,  and  a  really  accurate  mode  of  determining 
tlie  value  of  nitre  his  long  been  felt  as  a  want  by  chemists.  This  want  has  only  quite  re- 
cently been  supplied  by  Messrs.  Abel  and  Bloxam  of  the  Woolwich  Arsenal,  who  have 
devoted  much  labor  and  skill  to  the  subject,  the  importance  of  which,  in  connection  with 
the  art  of  war,  can  scarcely  be  over-estimated.  Before  detailing  the  new  and  successful 
process  of  the  latter  chemists,  we  will  take  a  brief  glance  at  the  other  methods  commonly 
used  for  the  purpose.  The  Fiench  process  depends  upon  the  principle  that  a  solution,  when 
saturated  with  one  salt,  is  still  capable  of  dissolving  a  considerable  quantity  of  saline  matter 
differing  in  its  nature  from  the  hist.  If,  therefore,  a  saturated  solution  of  nitre  be  poured 
upon  pnic  nitre,  no  more  is  dissolved  if  the  temperature  remains  the  same  as  it  was  when 
tlie  original  solution  was  prepai'ed.  But  if,  on  the  other  hand,  the  saturated  solution  of 
nitre  be  digested  with  an  imjjure  sample  containing  the  chlorides  of  sodium,  potassium,  &c., 
the  latter  .salts  will  be  dissolved,  and  the  pure  nitre  remaining  can,  after  proper  draining, 
&c.,  be  dried  and  weighed.  The  loss  of  weight  obviou.sly  represents  the  impurities  removed. 
This  process  is  subject  to  so  many  sources  of  error  that  the  practical  details  need  not  be 
entered  into. 

Another  mode  of  valuing  nitre  consists  in  fusing  the  salt,  and,  after  cooling,  breaking 
the  cake ;  the  tiiicness  or  coarseness  and  general  characteis  of  the  fracture  are  the  means 
whereby  the  greater  or  loss  value  of  the  salt  are  ascertained.  This  process,  which  is  known 
as  the  Swedish  or  .'>wartz's  method,  is  far  too  dependent  on  the  individual  experience  and 
dexterity  of  the  operator  to  be  of  any  value  in  the  hands  of  the  chemist  whose  attention  is 
only  now  and  then  directed  to  the  valiwtion  of  salii)etre.  Moreover,  although  those  who 
are  in  the  habit  of  using  it  possess  some  confidence  in  its  correctness,  it  is  quite  evident  that 
it  is  impossible  for  such  an  operation  to  yield  results  of  analytical  accuracy. 

The  Austiian  method  has  also  been  used  by  some,  but  it  is  quite  inadmissible  as  a  gen- 
eral working  process.  It  consists  in  ascertaining  the  temperature  at  which  the  solution 
crystallizes. 

(Jossart's  method  consists  in  determining  the  value  of  the  nitre  by  measuring  its  power 
of  oxidation.  The  latter  is  accomplished  by  finding  the  quantity  of  protoxide  of  iron  which 
it  can  convert  into  peroxide.  If  to  an  acid  solution  of  protosulphate  of  iron  nitj-ic  acid  or 
a  nitrate  be  added,  the  proto  is  converted  into  a  persalt  at  the  expense  of  a  portion  of  the 
oxygen  of  the  nitric  acid,  thus  : — 

2  (Fe0,80=)  -f  NO*  4-  SO^"  =  Fe-0=,  3S0'  -+-N0*. 
Theoretically  this  process  is  unexceptionable,  ))m  in  practice  it  is  liable  to  great  errors. 

M.  Pelouze  endeavored  to  improve  the  above  process  by  using  such  an  excess  of  the 
proto.salt  of  iion  that  the  nitre  added  should  be  able  to  convert  only  a  portion  of  it  into  a 
per.sait.  The  remaining  protoxide  was  then  converted  into  persalt  by  means  of  a  solution 
of  peimanganate  of  potash  of  known  strength.  The  data  so  obtained  enabled  the  value  of 
the  nitre  to  be  estimated.     But  even  this  process  is  liable  to  variations. 

The  next  process  which  we  shall  notice  is  that  wiiich  the  chemists  alluded  to  hare  finally 
settled  upon  as  yielding  the  best  results.  It  is  that  of  M.  Gay-Lus.sae.  It  depends  on  the 
fact  that  if  nitrate  of  potash  be  heated  with  charcoal,  or,  in  fact,  any  carbonaceous  matters 
i.i  exee.ss,  the  nitiate  is  converted  into  carl)onate  of  potash,  the  amount  of  which  may  be 
accurately  estimated  by  means  of  a  standard  solution  of  sulphuric  acid.  The  chlorides 
wliich  may  be  present  are  unacted  upon  by  the  charcoal,  and  do  not,  therefore,  inlluenee 


iOTASH,  NITRITE  OF.  Vi35 

the  result ;  but  if  sulphates  be  present  they  are  reduced  by  the  carbon  to  sulphides,  wliich, 
in  consequence  of  being  decomposed  by  the  sulphuric  acid,  may  cause  serious  errors. 
Fortunately  the  amount  of  sulphuric  acid  present  in  nitre  is  seldom  sufficient  to  cause  any 
great  error.  Any  nitrate  of  soda  present  would  come  out  in  the  final  result  as  nitrate  ot 
potash,  and  thus  become  another  source  of  error ;  in  practice  this  is  seldom  likely  to  occur. 
The  original  process  consists  in  weighing  out  20  grammes  (308-69  grains)  of  crude  saltpetre, 
and  mi.\ing  it  with  5  grammes  (77-17  grains)  of  charcoal,  and  80  grammes  (1234-7  grains) 
of  chloride  of  sodium.  The  mixture  is  thrown  little  by  little  into  a  red-hot  crucible,  and, 
when  the  decomposition  is  over,  allowed  to  cool.  The  residual  mass  is  dissolved  in  water, 
filtered,  and  water  passed  through  the  filter  until  it  amounts  to  200  cubic  centimetres,  (12-2 
cubic  inches.)  The  amount  of  alkali  is  then  ascertained  with  a  burette  and  standard  sul- 
phuric acid.  (See  Alkalimeter.)  Messrs.  Abel  and  Bloxam  have  minutely  and  laljorious- 
ly  studied  this  operation,  and  detected  its  sources  of  difficulty  and  error.  Their  researches 
have  led  them  to  employ  the  following  modification. 

Twenty  grains  of  the  sample  are  to  be  well  mixed'  in  a  platinum  crucible  with  30  grains 
of  finely-powdered  resin,  and  80  grains  of  pure  dry  common  salt.  The  heat  of  a  wire  gauze 
flame  is  then  applied,  until  no  more  vapor  is  given  off.  The  crucible  is  then  allowed  to 
cool  down  a  little,  and  25  grains  of  chlorate  of  potash  are  added.  A  gentle  heat  is  then 
applied  until  most  of  the  chlorate  is  decomposed  ;  the  hetit  is  then  raised  toJ>right  redness 
for  two  or  three  minutes.  The  mass  should  be  fluid,  and  free  from  floating  charcoal.  The 
mass,  when  cool,  is  removed  to  a  funnel,  and  the  crucible,  &c.,  washed  with  boiling  water. 
The  mass  is  then  dissolved  in  hot  water,  and  the  entire  solution,  colored  by  litmus,  is  neu- 
tralized with  the  standard  acid.  lu  the  annexed  table  20  grains  of  pure  nitre  were  taken 
for  each  experiment  :— 

Exp.  Nitre  found.  Nitre  per  cent. 

1.  20-00  100-00 

21  20  00  100-00 

3;  19-91  99-85 

4.  19-97  99-85 

5.  20-08  100-40 

6.  20-08  100-40 

7.  20-08  100-40 

The  authors,  not  yet  satisfied,  made  53  more  experiments  by  this  method.  The  mean 
result  with  pure  nitre  was  99-7  per  cent. 

The  mean  of  25  of  the  above  experiments  was  98-7  per  cent. 

The  mean  of  the  remainder  was  100-7  per  cent. 

Subsequent  experiments  showed  that  greater  accuracy  might  be  obtained  by  substituting 
for  the  resin,  pure  ignited  finely  divided  graphite,  prepared  by  Professor  Brodie's  patented 
process.  To  perform  the  process  20  grains  of  the  nitre  are  to  be  mixed  with  5  grains  of 
ignited  graphite  and  SO  grains  of  salt.  The  general  process  is  conducted  in  the  manner 
described  in  the  operation  with  resin.  The  results  are  very  exact,  and  apparently  quite 
sufficient  for  all  practical  purpose. — C.  G.  W. 

POTASH,  NITRITE  OF,  KO,NO^  When  ordinary  saltpetre,  or  nitrate  of  potash,  is 
heated  with  sulphuric  acid,  in  the  cold,  no  special  reaction  becomes  evident,  as  far  as  any 
evolution  of  gas  is  concerned  ;  but  if,  previous  to  the  addition  of  the  acid,  the  nitre  be 
strongly  fused,  it  will  be  found,  as  soon  as  the  admixture  takes  place,  that  red  fumes  are 
evolved.  This  arises  from  the  fact  that  nitrate  of  potash,  when  subjected  to  strong  ignition, 
is  decomposed  with  evolution  of  oxygen,  the  nitrate  becoming  gradually  converted  into  the 
nitrite  of  potash,  thus : — 

KO,NO'  =  KO,XO'  -f  20. 

This  reaction  acquires  great  interest  from  the  circumstance,  that  to  its  correct  explana- 
tion was  owing  the  commencement  of  the  fame  of  the  illustrious  Swedish  chemist  Schcele. 
A  pharmaceutist,  at  Ups;xla,  having  heated  some  saltpetre  to  redness  in  a  crucible,  hajjpen- 
ed,  when  it  became  cold,  to  pour  vinegar  over  it,  when,  to  his  surprise,  red  fumes  were 
evolved.  Gahn  was  applied  to  for  an  explanation ;  but,  unable  to  conipreheiul  the  m-attter, 
he  applied  to  liergmann  ;  but  even  he  was  as  nmch  in  the  dark  as  Gahn.  The  explanation 
which  these  eminent  chemists  were  unable  to  give,  was  supplied  by  the  pharmaceutist's  ap- 
prentice, the  young  Scheele.  Bergmann,  when  informed  by  (Jahn  of  Schecle's  explanation, 
felt  a  strong  desire  to  make  his  acquaintance,  and  ultimately  they  were  introduced  to  each 
other. 

Nitre  of  potash  has  acquired  some  importance  of  late  years,  owing  to  the  valuable 
propcritics,  as  a  decomposing  agent,  which  have  been  found  by  chemists  bo  reside  in  nitrous 
acid. 

Prepnrntion. — Nitrate  of  potash  is  to  be  fused  at  a  red  heat  for  a  considerable  time. 
When  cold,  the  contents  of  the  cruciljlc  are  to  be  dissolved  out  with  boiling  water,  and  the 
nitrate  of  potash  remaining  is  to  be  removed  as  far  as  possible  by  crystallization.  The 
nitrite  of  potash  may  be  obtained  from  the  mother  liquor  l)y  evaporation  and  subsequent 


930 


PRINTING  BLOCKS— ELECTRO. 


crvptallization.  It  is  a  neutral  salt,  which  deliquesces  on  exposure  to  the  air.  If  a  piece 
of  strongly-fused  nitre  bo  put,  when  cold,  into  a  solution  of  sulphate  of  copper,  a  very 
beautiful  apple-green  color  is  produced,  of  a  tint  which  is  seldom  observed  except  in  solu- 
tions containing  the  nitrite  of  that  metal. — C.  G.  W. 

PRLNTIXG  BLOCKS— ELECTRO.  WhUe  this  book  has  been  passing  through  the 
press,  Mr.  H.  G.  Collins  has  taken  out  two  patents,  which  are  likely  to  prove  of  essential 
service  to  the  publishing  world.  By  the  one  he  is  enabled  to  take  on  vulcanized  caout- 
chouc, prepared  with  an  equally  elastic  surface,  an  impression  in  transfer  from  anv  steel 
or  copper  plate,  wood  block,  stereotype,  lithographic  stoue,  or,  in  fact,  from  an  original 
drawing,  if  done  in  transfer  ink  on  transfer  paper,  and  increase  or  reduce  the  same  to  any 
required  size.  This  is  effected  by  expanding  the  India-rubber  in  one  case,  after  it  has  re- 
ceived the  impression ;  and  in  the  other,  before  the  impression  is  made.  In  the  first 
instance  the  impression  is  enlarged  as  the  elastic  material  expands,  in  the  other  it  is  reduced 
by  allowing  the  already  expanded  India-rubber  to  contract  in  its  frame ;  then  laying  the 
expanded  or  contracted  copy  down  upon  stone,  and  treating  it  after  the  usual  manner  of 
lithography.  This  prcscnt^i  a  vast  field  for  adapting  the  plates  of  any  work  of  acknowledged 
merit  which  may  liave  cost  some  hundreds  or  thousands  of  pounds,  and  years  to  produce, 
to  the  wants  of  the  public  in  these  days  of  cheap  and  well-illustrated  literature,  by  bringing 
out  the  same  works  in  a  reduced  size,  which,  but  for  this  plan,  no  pul)lis]ier  would  think  of 
attempting.  Many  plates,  also,  such  as  portraits,  public  buildings,  or  landscapes,  may  be 
enlarged  and  issued  scparatively.  This  last  application  is  particularly  suitable  for  maps,  as 
any  one,  from  the  size  of  a  school  atlas,  may  be  taken  and  made  to  serve  for  large  wall 
maps,  without  the  cost  of  engraving  the  same.  The  rapidity  with  which  this  alteration  of 
size  can  be  accomplished  is  not  among  the  least  of  its  recommendations  ;  for  an  engraving 
that  would  take  several  months  in  the  ordinary  mode  may  be  completed  in  from  two  to 
three  days. 

This  patent  offers  the  same  facilities  to  a  vast  number  of  the  manufactures  of  the 
country,  such  as  the  lace  trade,  cotton  printers,  damask  and  moreen  houses,  potteries, 
paper-hangings ;  in  fact,  to  all  and  every  one  who  employ  art  or  design  in  their  calling.  It 
will  be  well  to  observe  that  the  size  cannot  only  be  enlarged  or  diminished,  as  the  case  may 
be,  but  the  pattern  can  be  altered  in  form  ;  thus  a  circular  design  can  be  made  into  an  oval, 
if  required.  Mr.  Collins,  by  his  second  patent,  is  enabled,  after  these  impressions  are  once 
upon  the  stone,  to  make  them  into  electro  blacks,  thus  reducing  also  the  cost  of  printing 
engraved  plates,  which  is  effected  in  the  following  manner : — The  impression  being  placed 
on  the  lithographic  stone  or  the  zinc  plate — either  one  or  the  other  can  be  employed — acid 
is  applied  to  abrase  to  a  certain  extent  the  stone  or  metal  over  the  unprotected  portions ; 
when  this  is  sufficiently  deep  a  mould  is  taken  in  wax,  the  surface  of  which  being  prepared 
is  subjected  to  the  electrotype  process,  and  thus  a  copper  block  is  obtained. 

Mr.  C.  has  also  a  provisional  specification  for  a  third  patent,  by  which  he  can  by  the 
assistance  of  photography,  produce  blocks  for  surface  printing  (without  the  aid  of  the  en- 
graver) in  the  course  of  a  iev;  hours.  The  whole  of  these  patents  are  being  brought  into 
practical  operation  by  the  "  Electro  Printing-block  Company." 

PRIXTIXCr  M  ACHIXE.  An  American  machine,  the  invention  of  R.  Hoe  and  Company, 
of  New  York,  has  within  the  last  two  years  (1860)  been  introduced  to  this  country. 
Machines  of  this  description  have  been  made  for  Tlie  Tunes,  and  other  newspaper  offices, 
by  Mr.  Whitworth  of  Manchester.     The  following  is  Mr.  Hoe's  description  of  this  machine. 

A  horizontal  cylinder  of  about  4-V  feet  in  diameter  is  mounted  on  a  shaft,  with  appro- 
priate bearings  ;  about  one-fourth  of  the  circumference  of  this  cylinder  constitutes  the  bed  of 
the  press,  which  is  adapted  to  receive  the  form  of  types — the  remainder  is  used  as  a  cylin- 
drical distributing  table.  The  diameter  of  the  cylinder  is  less  than  that  of  the  form  of  types, 
in  order  that  the  distributing  portion  of  it  may  pass  the  impression  cylinders  without  touch- 
ing. The  Ink  is  contained  in  a  fountain  placed  beneath  the  large  cylinder,  from  which  it 
is  taken  by  a  ductor  roller,  and  transferred  by  a  vibrating  distributing  roller  to  the  cylin- 
drical distribution  table  ;  the  fountain  roller  receives  a  slow  and  continuous  rotary  motion, 
to  carry  up  the  ink  from  the  fountain. 

The  large  cylinder  being  put  in  motion,  the  form  of  types  thereon  is,  in  succession, 
carried  to  eight  corresponing  horizontal  impression  cylinders,  arranged  at  proper  distances 
around  it,  which  give  the  impression  of  eight  sheets,  introducing  one  at  each  impression 
cylinder.  For  each  impression  cylinder  there  are  two  inked  rollers,  which  vibrate  on  the 
distributing  surface  while  taking  a  supply  of  ink,  and  at  the  proper  time  pass  over  the  form, 
when  they  again  fall  to  the  distributing  surface.  Each  page  is  locked  up  u]3on  a  detached 
segment  of  the  large  cylinder,  called  by  the  compositors  a  "turtle,"  and  this  constitutes  the 
bed  and  chase.  The  column  rules  run  parallel  with  the  shafts  of  the  cylinder,  so  as  to  bind 
the  types  near  the  top.  These  wedge-shaped  column  rules  are  held  down  to  the  bed  or 
"turtle ''by  tongues,  projecting  at  intervals  along  their  length,  and  sliding  in  rebated 
grooves  cut  cross-wise  in  the  face  of  the  bed ;  the  space  in  the  grooves  between  the  column 
rules  being  filled  with  sliding  blocks  of  metal,  accurately  fitted,  the  outer  surface  level  with 


PIIIXTIXG  AND  NUMBERING  CAliDS. 


9:3'; 


the  surface  of  the  bed,  the  ends  next  the  column  rules  being  cut  away  underneath  to  receive 
a  projection  on  the  sides  of  the  tongues  and  screws  at  the  end  and  side  of  each  page  to 
lock  them  together,  the  tvpes  are  as  secure  on  this  cylinder  as  thev  can  be  ou  the  old  flat 
bed. 

In  Tlie  Times  office  there  are  two  of  those  machines,  one  of  them  being  a  ten-cylinder 
machine,  which  is  regularly  employed  to  print  10,00i)  sheets  an  hour,  and  it  appears  capable 
of  printing  18,000.  It  is  only  l^y  means  of  tlicse  two  American  machines,  and  two  of  Ap- 
plegath's,  all  working  on  the  diti'erent  sides  of  the  paper,  that  the  enormous  supply  required 
every  morning  can  be  produced. 

The  first  successful  application  of  steam,  a.s  a  motive  power,  to  printing  presses  with  a 
platen  and  vertical  pressure,  was  made  in- the  office  where  this  book  is  being  printed.  Con- 
vinced of  the  superiority  of  the  impression  made  by  flat  as  compared  with  that  of  cylindrical 
pressure,  Mr.  Andrew  Spottiswoode,  assisted  by  his  chief  engineer,  Mr.  Brown,  succeeded, 
after  many  experiments,  in  perfecting  a  machine  whicli  combines  the  excellence  of  the  hand 
press  with  more  than  four  times  its  speed,  and  a  uniformity  in  color  which  can  never  be 
attained  by  inking  by  hand.  The  main  point  of  the  invention  is  the  endless  screw  or  drum 
which  takes  the  carriage  and  type  under  the  platen,  and  after  the  impression  is  taken  re- 
turns it  to  its  original  position. 

PRINTING  AND  NUMBERING  CARDS.  It  will  be  remembered  in  the  early  days  of 
railway  travelling,  the  ticket  system  then  in  vogue  at  the  various  stations  was  a  positive 
nuisance ;  as  evei'y  ticket  before  it  was  delivered  to  a  passenger  had  to  be  .'^tamped,  and 
torn  out  of  a  book — tluis  causing  the  lo.ss  of  considerable  time  to  travellers  when  many 
passengers  were  congregated.  The  first  to  remedy  this  was  Mr.  Edmondson,  who  constiuct- 
ed  an  ingenious  apparatus  for  printing  the  tickets  with  consecutive  numbers,  and  also 
dating  the  same.  This  gave  great  facilities  for  checking  the  accounts  of  the  station  clerks; 
but  owing  to  the  imperfect  manner  of  inking,  consequent  ou  the  construction  of  the  appara- 
tus, the  friction  to  wliich  the  tickets  were  exposed,  before  they  were  delivered  up,  in  a 
great  manner  obliterated  the  printing,  and  occasionally  rendered  them  quite  illegible.  By 
Messrs.  Church  and  Goddard's  machine  for  printing,  numbering,  cutting,  counting  and  pack- 
ing railway  tickets,  this  diificulty  is  removed,  and  great  speed  is  attained  in  manufacturing 
tickets,  as  the  several  operations  are  simultaneously  performed.  Pasteboard  cut  into  strips  by 
meaus  of  rollers  is  fed  into  the  machine,  by  being  laid  in  a  trough,  and  brought  under  the 
prongs  of  a  fork,  (working  with  an  intermitting  movement,)  which  pushes  the  strips  succes- 
sively forward  between  the  first  pair  of  a  series  of  guide  or  carrying  rollers.  There  are  four 
pairs  of  rollers,  placed  so  as  to  conduct  the  strip  through  the  machine  in  a  horizontal  line ; 
and  an  intermittent  movement  is  given  them  for  the  purpose  of  carrying  the  strips  forward 
a  short  distance  at  intervals.  The  standards  of  the  machine  cany,  at  the  top,  a  block  term- 
ed the  "  pattern,"  as  it  acts  the  part  of  the  press-head  in  the  common  printing  machine — 
portions  of  it  projecting  downwards  between  the  upper  rollers  of  the  first  and  second,  and 
second  and  third  pairs  of  carrying  rollers,  to  the  horizontal  plane,  in  which  the  paste- 
board lies,  so  as  to  sustain  it  at  those  points  while  it  receives  the  pressure  of  the  printing  types 
and  numbering  discs,  hereafter  referred  to.  The  types  to  designate  the  nature  of  the  ticket, 
as  "  Birmingham,  First  Class,"  are  secured  in  a  "chase,"  upon  a  metal  plate  or  table,  which 
also  carries  the  numbering  discs  for  imprinting  the  figures  upon  the  cards ;  and  the  table  by  a 
cam  action  is  alternately  raised,  to  bring  the  types  and  numbering  discs  in  contact  with  the 
pasteboard,  and  then  lowered  into  a  suitable  position,  to  admit  of  an  inking  roller  moving 
over  the  types  and  numbering  discs,  and  applying  ink  thereto.  The  table  likewise  carries 
at  one  end  a  knife,  which  acts  in  conjunction  with  a  knife-edge,  projecting  downwards  from 
the  fixed  head  of  the  machine,  and  thereby  gives  the  cross-cut  to  the  strips  between  tlie 
third  and  fourth  pairs  of  carrying  rollers, — thus  severing  each  into  a  given  number  of  tickets. 
The  strip  of  pasteboard  which  is  fed  into  the  machine  stops  on  arriving  at  the  second  ]wir 
of  carrying  rollers ;  and,  on  the  ascent  of  the  printing  tal)le,  the  types  print  on  that  jiortion 
which  is  between  the  first  and  .second  pairs  of  rollers.  The  strip  then  passes  on  to  the  third 
piir  of  rollers,  where  it  stops;  and,  on  the  table  again  ascending,  the  numbering  discs  im- 
))rint  tlie  proper  number  upon  the  pasteboard  between  the  second  and  third  pairs;  the  type, 
in  the  meanwhile,  printing  what  is  to  be  the  next  following  ticket.  On  the  next  ascent  of 
the  table,  the  strip  has  advanced  to  the  fourth  pair  of  rollers ;  and  the  knives  ln-ing  now 
brought  into  contact,  the  printed  and  numbered  portion  of  the  .strip  is  severed.  The  now 
com[)leted  ticket  is  lastly  delivered  Ijy  the  fourth  jjair  of  rolleis  into  a  hollow  guide  piece, 
and  conducted  to  a  box  below,  provided  with  a  piston,  which,  to  facilitate  the  packing  of 
the  tickets  in  the  box,  can  be  adjusted  to  any  height  to  i-eceive  the  tickets  as  they  fall.  To 
avoid  the  necessity  of  having  to  count  the  tickets  after  they  are  taken  from  the  receiving 
box,  a  counting  apparatus,  connected  with  the  working  parts  of  the  machine,  is  maile  to 
strike  a  l)ell  on  the  completion  of  every  hundred  or  more  tickets,  so  as  to  warn  the  attend- 
ant to  remove  them  from  the  box.  Tlie  inking  apparatus  is  assimilated  in  diaracter  to 
self-acting  inkers  in  ordinary  ]ninting  piesses ;  and  the  numbering  di.scs  are  worked  in  a 
m miKv  verv  similar  to  tjiose  for  {)aging  books. 


9;J8  PRINTING  ROLLERS. 

A  simple  arrangement  of  apparatus  for  printing  and  numbering  cards  Iw.s  been  intro- 
duced liy  Jle.s.srs.  ilarrild  and  Sons.  The  types  are  fixed  in  a  metal  franie,  winch  also 
carries  the  numbering  discs.  This  frame  is  mounted  on  a  rocking  shaft,  and  is  furnished 
with  a  handle,  whereby  it  is  rocked  to  bring  down  the  types  and  discs  upon  the  card,  to 
produce  the  impression.  When  the  frame  is  raised  again,  the  units  disc  is  moved  forward 
one  figure,  and  the  t}'pes  are  inked  by  a  small  roller,  which  takes  its  supply  of  ink  from  an 
inking  table,  that  forms  the  top  of  the  frame. 

M.  Baranowski,  of  Paris,  invented  a  machine  foj  printing  and  numbering  tickets,  and 
also  indicating  the  number  printed.  The  types  and  numbering  discs  are  carried  by  a  hori- 
zontal rotating  shaft,  upon  which,  near  each  end  thereof,  is  a  metal  disc;  and  upon  the 
periphery  of  these  discs  a  metal  frame  is  affixed,  which  carries  the  types  and  numbering 
tiises,  and  corresponds  in  curvature  with  the  edge  of  the  discs.  The  types  for  printing  the 
inscription  upon  the  ticket  are  arranged  at  right  angles  to  the  length  of  the  shaft,  which 
position  admits  of  some  lines  of  the  inscription  being  printed  in  one  color,  and  the  remain- 
der in  another  color.  In  the  type  frame  a  slot  or, opening  is  formed  lengthwise  of  the  shaft ; 
and  behind  this  opening  are  three  numbering  discs,  and  three  discs  for  indicating  the  quanti- 
ty of  tickets  numbered — all  standing  in  the  same  row.  The  numbering  discs  are  made 
with  raised  figures,  which  project  through  the  slot,  in  order  to  print  the  number  upon  the 
ticket ;  and  on  the  peripheries  of  the  registering  discs  (which  move  simultaneously  with 
their  corresponding  numbering  discs)  the  figures  are  engraved.  The  tickets  to  be  printed 
and  numbered  are  placed  in  a  rectangular  box  or  receiver,  having  at  the  bottom  a  fiat  slid- 
ing piece,  which  has  a  recipiocating  motion  for  the  purpose  of  pushing  the  lowest  ticket  out 
of  the  box,  through  an  opening  in  the  front  side  thereof,  beneath  an  elastic  pressing-roller 
of  India-rubber  ;  the  type-frame  (with  the  types  and  figures  properly  inked)  is  at  the  same 
time  brought,  by  the  rotation  of  its  shaft,  into  contact  with  the  ticket  beneath  the  pressing 
roller,  and  as  it  continues  its  motion,  it  causes  the  ticket  to  move  forward  beneath  the 
pressing  roller,  and  to  be  properly  printed  and  numbered.  The  ticket  then  falls  from  the 
machine  ;  and  the  type-frame,  carried  on  by  the  revolution  of  the  shaft,  brings  that  number 
on  the  registering  discs  which  corresponds  with  the  number  printed  on  the  ticket,  under  a 
small  opening  in  the  case,  covered  with  glass;  whereby  the  number  of  tickets  printed  will 
be  indicated. 

PRIXTIXG  ROLLERS.  Elastic  inking  rollers  were  introduced  by  Messrs.  Donkin  and 
Bacon.  They  are  made  of  a  mixture  of  glue  and  treacle,  or  of  glue  and  honey  ;  the  Ameri- 
can honey,  it  is  said,  being  pieferred.  1  pound  of  good  glue  is  softened  by  soaking  in  cold 
water  for  twelve  hours,  and  then  it  is  united,  by  means  of  heat,  with  about  2  pounds  of 
ordinary  treacle. 

Messrs.  Hoe  and  Co.  give  the  following  directions  for  making  and  preserving  composition 
rollers: — For  ci/liiidir-prcss  roncr!<,  Cooper's  No.  1.  x  glue  is  sufficient  for  ordinary  pur- 
poses, and  will  pe  found  to  make  as  durable  rollers  as  higher  priced  glues. 

Place  the  glue  in  a  bucket  or  pan,  and  cover  it  with  water ;  let  it  stand  half  an  hour,  or 
until  about  lialf  penetrated  with  water,  (care  should  be  used  not  to  let  it  soak  too  long,) 
then  pour  it  off,  and  let  it  remain  until  it  is  soft.  Put  it  in  the  kettle  and  cook  it  until  it  is 
thoroughly  melted.  If  too  thick,  add  a  little  water  until  it  becomes  of  proper  consistency. 
The  molasses  may  then  be  added,  and  well  mixed  with  the  glue  by  frequent  Ftirring. 
When  properly  prepared,  the  composition  does  not  require  boiling  more  than  an  hour. 
Too  much  boiling  candies  the  molasses,  and  the  roller  consequently  will  be  found  to  lose 
its  suction  much  sooner.  In  proportioning  the  material,  much  depends  upon  the  weather 
and  temperature  of  the  place  in  which  the  rollers  are  to  be  used.  8  pounds  of  glue  to  1 
gallon  of  sugar-house  molasses,  or  syrup,  is  a  very  good  proportion  for  summer,  and  4 
pounds  of  glue  to  1  gallon  of  molasses  for  winter  use. 

Hand-prcfis  rollers  may  be  made  of  Cooper's  No.  1^^  (one  and  a  quarter)  glue,  using  more 
molasses,  as  they  are  not  subject  to  so  much  hard  usage  as  ci/lbidcr-prcsx  rollers,  and  do  not 
require  to  be  as  strong ;  for  the  more  molasses  that  can  be  used  the  better  is  the  roller 
Before  pouring  a  roller,  the  mould  should  be  perfectly  clean,  and  well  oiled  with  a  swab, 
but  not  to  excess. 

Rollers  should  not  be  wa.shed  immediately  after  use,  but  should  be  put  away  with  the 
ink  on  them,  as  it  protects  the  surface  from  the  action  of  the  air.  When  washed  and  ex- 
posed to  the  atmosphere  for  any  length  of  time,  they  become  dry  and  skinny.  They  should 
be  wiished  about  half  an  hour  f)efore  using  them.  In  cleaning  a  new  roller,  a  little  oil 
rubbed  over  it  will  loosen  the  ink,  and  it  should  be  scraped  clean  with  the  back  of  a  case 
knife.  It  .should  be  cleaned  in  this  way  for  about  one  week,  when  h/e  may  be  used.  New 
rollers  are  often  spoiled  by  washing  them  too  soon  with  lye.  Camphene  may  be  substituted 
for  oil ;  but  owing  to  its  cumbustible  nature  it  is  objectionable,  as  accidents  may  ari-se  from 
its  use. 

PROVING  MACHINE.  The  drawing  shows  a  useful  machine  for  testing  the  quality 
and  power  of  India-rubber  springs,  designed  by  Mr.  George  Spencer,  of  the  firm  of  Geo. 
Spencer  and  Co.,  and  used  by  them  for  that  purpose.     Fiff.  575  shows  an  elevation,  partly 


PURPLE  DYES. 


'J3'J 


in  section,  of  the  machine ;  fg.  576  a  plan  of  the  same,  a  is  a  strong  cast-iron  frame,  sup- 
ported by  two  cast-iron  standards,  b  ;  c  is  a  sliding  piston,  working  iu  a  hole  cast  in  the  end 
of  frame  a,  one  end  of  which  impinges  against  the  short  arm  of  a  strong  cast-iron  lever,  d, 


J^        r 


forming  one  of  a  system  of  compound  levers  as  shown,  having  fulcrumsat  f  and/,  and  pro- 
vided with  a  Salter's  balance,  17,  to  register  the  power  exerted  by  the  spring. 

At  the  other  end  of  frame,  a,  a  brass  nut,  a,  is  placed  in  a  hole  in  the  frame,  through 
which  a  square-threaded  screw,  s,  works  by  means  of  the  handle,  11,  or  by  a  long  lever  of 
wrought  iron,  according  to  the  power  of  spring  to  be  tested. 

The  spring  to  be  tested  is  placed  between  the  two  sliding  guide  plates,  n,  n',  and  a 
wrought-iron  bolt  passed  through  the  plates,  n,  n',  and  spring,  z,  and  passing  into  the  hollow 
piston,  c,  for  the  purpose  of  keeping  the  spring  in  correct  position,  and  receiving  in  its 
hollow  head,  M,  the  end  of  the  screw,  s.  The  action  may  be  thus  described : — The  handle, 
II,  being  turned,  the  screw,  s,  advances  and  pushes  on  the  plate,  n',  by  means  of  the  bolt- 
head,  M.  The  other  plate,  n,  rests  against  the  piston,  c,  and  is  pressed  against  it  by  the 
intervening  spring,  z.  The  leverage,  n,  is  so  arranged  that  1  lb.  on  the  dial  is  equal  to  2 
cvvt.  on  the  spring,  or,  in  other  words,  is  1  in  224.  Springs  of  a  force  of  20  tons  can  be 
tested  by  this  machine  safely.     See  Caoutchouc. 

PRUSSIAN  BROWN.  A  fine  deep  ))rown  color  obtained  by  adding  the  yellow  prus- 
siate  of  potash  {fi'n-oprusainf.e)  to  a  solution  of  sulphate  of  copper. 

PURPLE  DYES.  The  purple  dyes  now  oljtained  liy  more  or  less  complex  processes 
from  coal  tar,  are  so  incomparably  superior  to  any  others,  both  in  brilliancy  and  perma-. 
nence,  that  their  production  has  opened  up  a  new  era  in  dyeing  and  calico-printing.  The 
process  of  Mr.  Perkin,  the  discoverer  of  aniline  purple,  is  simple  in  principle,  but  the  opera- 
tions, from  the  production  of  the  coal  tar  to  the  formation  of  the  pure  purple,  are  so  numer- 
ous, and  require  to  be  conducted  on  such  a  large  scale,  that  the  successful  manufacture  in- 
volves the  necessity  for  large  capital  and  considerable  chemical  skill.  Mr.  Perkin's  process 
involves  the  following  operations  : — 

1.  Production  of  benzole  from  coal  tar  by  fractional  distillation. 

2.  Conversion  of  benzole  into  nitro-benzole  by  the  action  of  nitric  acid. 

3.  Conversion  of  nitro-benzole  into  aniline. 

4.  Production  of  neutral  .sulphate  of  aniline. 

5.  Decomposition  of  sul|)hate  of  aniline  by  bichromate  of  potash. 

6.  Washing  with  water  of  the  ])Tecipitate  by  bichromate  of  potash. 

7.  Drying  of  the  washed  precipitate. 

8.  Extraction  of  the  lirown  impurity  contained  iu  the  precipitate. 
0.  Extraction  of  the  purple  coloring  matter. 

An  outline  of  the  process  contained  in  Mr.  Perkin's  specification  will  be  found  in  the 
article  Animnk. 

Numerous  patents  have  been  taken  out  for  the  production  of  colors  more  or  less  reseni- 
liling  Perkin's  purple.  J.  T.  Bealc  and  J.  N.  Kirkham  employ  l)leaching  powder  as  the 
oxidizing  ineiliiini.  They  take  a  saturated  solution  of  aniline  in  water,  and  add  to  it  acetic 
ariil  and  bleaching  powder  until  the  desired  tint  is  ac(iiiir<Ml.  They  then  use  the  fluid  so 
procured  for  dyeing.     It  is  obvious  that  some  i)roccss  of  concentration  must  be  employed 


940  PYROLIGNEOUS  ACID. 

to  enable  so  weak  a  fluid  to  be  employed  in  calico-printing.  Upon  the  latter  point  the 
patent  process  does  not  enter  at  sullicient  length  to  enable  us  to  judge  of  the  practicability 
of  producing  colois  of  the  great  strength  required  for  printing  on  with  albumen.  Messrs. 
IJeale  and  Kirkham,  by  modifying  the  nature  of  the  salt  and  the  state  of  concentration  of 
the  tluids  employed,  olrtain  various  shades  of  color  from  blue  to  lilac. 

Mr.  R.  D.  Kay,  in  his  patent  of  the  7th  May,  1859,  treats  acetate,  sulphate,  or  hydro- 
chlorate  of  aniline,  with  peroxide  of  manganese,  peroxide  of  lead,  or  chloride  of  lime. 

Mr.  David  S.  Price,  in  his  patent  of  the  25th  of  May,  1859,  claims  the  use  of  peroxide 
or  sesquioxide  of  manganese,  and  also  peroxide  of  lead,  as  his  agent  of  oxidation.  By 
vaiying  the  quantities  of  his  ingredients  he  obtains  three  colors,  viz.,  violine,  purpuriue,  and 
roseine. 

C.  H.  G.  Williams  patents  the  green  manganate  of  potash  as  the  oxidizing  agent.  By 
this  means  a  part  of  the  aniline  is  converted  into  a  brilliant  red  dye  of  great  beauty,  and 
another  part  into  an  equally  brilliant  purple.  The  two  colors  arc  separated  by  taking 
advantage  of  the  fact  that  the  purple  is  precipitated  by  a  solution  of  the  reagent,  whereas 
the  red  color  remains  in  solution,  and  can  be  concentrated  by  evaporation. 

In  dyeing  and  printing  with  these  colors  it  is  necessary  with  vegetable  fabrics  to  use 
mordants,  but  animal  fabrics  absorb  the  colors  with  great  avidity  without  the  use  of  any 
mordant. 

P'or  cottons,  pcrchloride  of  tin,  followed  by  sumach,  or  stnnnate  of  soda  and  sumach, 
are  the  best  mordants.  Mr.  Perkin  recommends  tartaric  acid  to  be  added  to  the  bath  in 
dyeing;  but  in  practice  this  reconmiendation  is  not  generally  followed. 

Por  printing,  the  purple  is  mixed  with  albumen  ;  and  after  printing  with  the  mixture  the 
color  is  fixed  l)y  steaming.  Sometimes  a  mordant  is  printed  on,  and  the  pattern  is  obtained 
b)'  passing  the  mordanted  cloth  through  a  bath  of  the  color.  The  purple  may  be  rendered 
of  a  bluer  and  very  lovely  tint  by  adding  to  the  mixture  of  dye  and  albumen  a  little  carmine 
of  indigo  ;  Prussian  blue  is  also  sometimes  used  for  the  same  purpose.  In  selecting  patterns 
to  be  printed  in  purple,  it  must  not  be  forgotten  that  the  beauty  of  the  tint  is  greatly  en- 
hanced by  the  proximity  of  blacks  properly  arranged. 

Very  fine  purples,  but  decidedly  inferior  to  Mr.  Perkin's  color,  are  now  prepared  from 
litmus;  they  are  also  tolerably  permanent.  They  are,  nevertheless,  liable  to  the  drawback 
of  becoming  red  in  contact  with  strong  acids.  Strange  to  say,  however,  the  orchil  purples 
when  properly  made  resist  very  well  the  action  of  weak  acids.  The  color-producing  acids 
are  obtained  by  treating  the  lichens  with  an  alkaline  base,  which  forms  a  soluble  salt.  The 
filtered  liquid  on  treatment  with  an  acid  gives  an  abundant  precipitate.  It  is  this  latter 
which,  by  proper  treatment,  yields  the  "  French  purple."  The  following  is  an  outline  of 
the  process  contained  in  a  patent  granted  to  "William  Spence,  (being  a  French  communica- 
tion.) dated  1st  May.  1858. 

The  precipitate  obtained  as  above  is  moistened  with  sufficient  ammonia  to  dissolve  it. 
On  boiling,  the  .solution  becomes  orange  yellow  ;  it  is  then  exposed  to  the  air  at  ordinary 
temperatures,  until  it  becomes  red.  The  fluid  is  then  heated  in  very  .shallow  vessels  to  a 
temperature  between  100'  and  140'  Fahr.,  until  it  becomes  of  a  violet  color,  which  is  un- 
alterable by  weak  acids,  and  which  will  dye  permanent  colors  on  silk  or  wool,  without  the 
aid  of  mordants. 

This  purple  color  can  be  thrown  down  from  the  liquid  by  saturation  with  an  acid.  The 
precipitate,  after  being  filtered  ofl'  and  properly  dried,  is  in  a  fit  condition  for  dyeing  or 
printing. 

Like  Perkin's  purple,  various  shades  may  be  obtained  by  using  the  orchil  purple  in  com- 
bination with  carmine  of  indigo  for  violet.s,  and  carthamus,  or  cochineal,  for  reds. — C.  G.  W. 

PYROLIGXEOUS  ACID.  A  new  mode  of  distilling  wood  and  producing  this  acid  has 
been  introduced  by  Mr.  W.  H.  Bowers,  of  Manchester.  In  the  rectangular  retort  which  is 
used  there  are  two  revolving  drums,  one  at  each  end.  On  these  drums  are  endless  chains ; 
on  these  chains  there  is  formed  a  flat  surface  by  means  of  bars  laid  across.  A  hopper 
supplies  this  surface  with  the  sawdust  or  other  material  to  be  heated.  The  sui  face  is  some- 
what inclined.  A  very  small  engine  is  used  to  set  the  endless  chain  in  motion.  The  saw- 
dust is  carried  from  the  upper  end  of  the  retort  to  the  lower,  during  which  time  it  is  exposed 
to  heat  and  becomes  distilled.  At  the  lower  end,  as  it  is  turning  over  the  drum,  it. falls  in 
a  carbonized  state  into  water.  The  vapors  are  cariied  away  by  pipes,  as  in  the  usual 
method,  and  the  water  joint  at  the  lower  part  of  the  retort  prevents  any  escape  in  that 
direction,  whilst  the  thickness  of  the  mass  of  sawdust  passing  into  the  retort  readily  pre- 
vents any  from  passing  out  there.  It  is  said  that  one  retort  can  do  the  work  of  five  of  those 
made  on  Ilalliday's  plan  with  the  screw.  Two  of  them  produce  with  slow  motion  2,500 
gallons  of  acid  in  six  days.  The  motion  may  be  increased  at  will,  and  heat  regulated 
accordingly.  There  are  scrapers  to  jn-event  charcoal  clogging  the  bars  forming  the  inclined 
plane,  antl  the  apparatus  does  not  require  to  be  stopped  for  any  purpose  of  cleansing.  It 
feeds  and  discharges  continuously,  from  month  to  month. 

Sawdust,  wood  turnings,  small  chips,  spent  dye  wood,  and  tanners'  bark,  peat,  and  such 


PYROXILIC  SPIRIT. 


941 


like  ligneous,  and  carbonaceous  substances,  are  distilled,  and  the  carbon  discharged  as 
shown. 

It  is  believed  also  that  the  distillation  is  effected  more  rapidly,  and  the  gases  more 
directly  removed  by  this  method,  than  by  any  other. 

Fig.  577  is  a  longitudinal  section  taken  through  the  middle  of  the  retort  or  rectangular 


vessel  rt,  «,  a\  b,b  are  the  revolving  drums  on  which  the  endless  chain  e,  e,  e  revolves ;  /,  / 
are  cross-bars  or  scrapers  ;  g,  g  are  tubes  to  convey  the  gases,  one  from  the  lower  and  one 
from  the  higher  point  of  the  moving  plane ;  /i  is  a  hopper  filled  with  sawdust  and  other 
material  to  be  distilled ;  the  supply  is  regulated  by  two  small  cog-wheels  i,  i ;  j,  the  fire- 
])lace  ;  k,  k,  the  flues  ;  ?«  is  a  cistern  showing  the  level  of  the  water  and  the  carbon  falling 
into  it,  the  lower  part  of  the  retort  dipping  into  it. 

PYROXILIC  SPIRIT.  Spi.  Pyroligncous  spirit,  Pgroligneoiis  ether,  Wood-spirit, 
Wood-naphtha,  Methi/lic  alcohol.  Hydrate  of  methyle,  ^Hydrated  oxide  of  methyle. 
C-II^O^  =  C^H=0,HO.  'Density  of  strongest  wood-spirit  at  32%  0-8179.  Density  at  (58°, 
0708.     Density  of  vapor,  1 -12 =4  volumes.     Boihng-point,  150°  F. 

Wood-spirit  was  first  recognized  as  a  distinct  substance  by  Taylor,  in  1812.  Its  true 
nature,  however,  was  unknown  until  the  appearance  of  the  important  research  of  MM.  Du- 
mas and  Peligot,  in  1835. 

Pyroxilic  spirit  is  obtained  from  the  liquid  products  of  the  distillation  of  wood  by  tak- 
ing advantage  of  its  superior  volatility.  The  crude  wood-vinegar,  if  distilled  per  se,  yields 
up  to  a  certain  point  highly  impure  and  weak  spirit.  It  is,  however,  free  from  ammonia 
and  alkaloids.  If,  on  the  other  hand,  the  vinegar  is  first  neutralized  by  lime  or  soda  pre- 
vious to  the  distillation  of  the  spirit,  it  is  rendered  more  free  from  acetate  of  methyle  and 
some  other  impurities,  but  it  then  contains  alkaloids  and  ammonia.  At  times  the  quantity 
of  the  latter  substance  present  is  so  large  that  the  spirit  smokes  strongly  on  the  approach 
of  a  rod  dipped  in  hydrochloric  or  acetic  acid.  In  order  to  apply  this  test  it  is  obvious  that 
the  hydrochloric  acid  must  be  diluted  until  it  does  not  fume  by  itself.  By  repeated  rectifi- 
cations over  lime  or  chalk,  rejecting  the  latter  portions,  the  wood-spirit  may  be  obtained 
colorless,  and  of  a  .strength  varying  from  80  to  90  per  cent,  of  pure  spirit,  the  specific  grav- 
ity being  from  0-870  to  0-830. 

Inasmuch  as  wood-spirit  boils  at  a  temperature  far  less  than  the  point  of  ebullition  of 
the  impurities  ordinarily  found  in  it,  it  may  always  be  greatly  improved  in  solvent  power, 
appearance,  and  odor,  by  mere  rectification  on  the  water  bath  or  in  a  rectifying  still.  But, 
nevertheless,  a  certain  quantity  of  the  more  volatile  impurities  always  accompany  the  me- 
tliylic  alcohol,  being  carried  over  with  its  vapor.  Among  the  foreign  bodies  may  be  men- 
tioned the  hydrocarbons  of  the  benzole  scries.  Tlicse  may  be  entirely  removed  by  mixing 
the  crude  spirit  with  three  or  four  times  its  volume  of  water;  the  hydrocarbons  are  thus 
rendered  insoluble  and  rise  to  the  surface  of  the  fluid.  By  means  of  a  separator  the  lower 
layer  may  be  removed,  and  after  two  or  three  rectifications,  at  as  low  a  temperature  as  pos- 
sible, the  spirit  may  be  proeurcd  (piite  clean. 

To  ol)tain  wood-spirit  (piite  pure  it  is  generally  recommended  to  mix  it  with  chloride  of 
calcium,  and  again  rectify  on  a  steam  or  water  bath.  By  o])eratiiig  in  tliis  manner,  the  me- 
thylic  alcohol  combines  with  the  chloride  of  calcium,  forming  a  com])ound  not  decompos- 
able at  the  temi)erature  of  the  water  bath.  The  impurities  present  therefore  distil  away, 
leaving  in  the  still  a  compound  of  pure  mcthylic  alcohol  with  chloride  of  calcium.  But 
this  latter  compound  possesses  little  stability,  and  may  be  decomposed  by  the  mere  addition 


942  PYROXILIC  SPIKIT. 

of  water,  which  liberates  the  spirit.  It  is  then  to  be  distilled  away  from  the  salt,  and  alter 
one  or  two  rectifications  over  (luicklime  will  be  quite  pure. 

It  is  highly  important  that  wood-spirit  should  be  of  considerable  purity  if  required  for 
the  purpose  of  dissolving  the  gums.  It  is  true,  that  as  far  as  its  use  for  dissolving  shellac 
is  concerned,  there  is  no  need  for  extreme  purity,  as  shellac  will  dissolve  in  most  specimens 
of  wood-spirit.  But  it  is  not  in  this  case  the  mere  solvent  power  that  is  required  ;  for  if  a 
solution  of  shellac  in  impure  wood-spirit  be  employed  by  hatters,  the  vapor  evolved  is  so 
irritating  to  the  eyes  that  the  workmen  are  unable  to  proceed.  If  the  spirit  has  the  proper- 
ty of  fuming  on  the  appioach  of  a  rod  dipped  in  acetic  or  hydrochloric  acids,  it  may  bo 
taken  for  granted  that  it  will  be  incapable  of  dissolving  gum  sandarach.  This  arises  from 
the  fact  that  such  spiiit  has  been  distilled  from  an  alkaline  base,  such  as  lime  or  soda,  and 
contains  alkaloids,  ammonia,  and  various  other  impurities  which  destroy  its  solvent  power. 
Tiie  alkaline  reaction  may  be  destroyed  and  the  spirit  rendered  fit  for  use  Ijy  adding  2  or  3 
per  cent,  of  suli)huric  acid  and  then  distilling.  The  alkaloids  and  many  other  impurities 
will  then  be  retained,  and  the  spirit  may  either  be  used  at  once  or  still  further  purified  by 
dilution  with  water  and  subsequent  rectification.  It  is  possible  to  combine  the  two  processes 
at  one  operation,  by  diluting  the  .spirit  with  four  times  its  bulk  of  water,  and  adding  just 
enough  oil  of  vitriol  to  the  diluted  liciuid  to  give  it  a  faint  acid  reaction  to  htmus  paper.  It 
is  absolutely  essential  to  the  success  of  this  process  that  the  mixture  of  spirit  water  and  acid 
be  perfectly  well  mixed. 

A  wood-spirit  which  refuses  to  dissolve  sandarach  may  often  be  rendered  a  good  solvent 
by  adding  from  5  to  7  per  cent,  of  acetone.     See  Acetone. 

When  wood-spiiit  is  required  in  a  state  of  extreme  purity  for  the  purpose  of  research, 
it  may  be  obtained  by  distilling  oxalate  of  methyle  with  water.  Oxalate  of  methyle,  or 
iiicthyle  oxalic  ether  may  be  obtained  by  distilling  equal  parts  of  sulphuric  acid,  oxalic  acid, 
and  wood-spirit.  The  distillate  when  evaporated  very  gently  yields  crystals  of  the  com- 
pound in  question.  As  it  does  not  volatilize  below  322°  F.,  the  retort  containing  the  male- 
rials  for  its  preparation  requires  to  be  pretty  strongly  heated  to  bring  the  ether  over.  It 
may  be  purified  by  sublimation  from  oxide  of  lead. 

Pure  methylic  alcohol  is  a  colorless  transparent  liquid,  neutral,  very  inflammable,  burn- 
ing with  a  blue  flame  like  common  alcohol.  It  has  a  very  nauseous  flavor,  and  is  fiery  in 
the  mouth.  It  dissolves  in  any  proportion  in  water,  alcohol,  or  ether,  and  is  a  good  solvent 
for  fatty  bodies  and  certain  resins.     It  is  miscible  with  essential  oils. 

Wood-spirit  may  be  detected,  according  to  Dr.  Ure,  even  when  greatly  diluted  with  alco- 
hol, by  the  brown  color  which  it  assumes  in  presence  of  solid  caustic  potash.  Even  when 
alcohol  contains  only  2  per  cent,  of  wood-spirit,  it  acquires  a  yellow  tint  in  10,  minutes  on 
addition  of  powdered  caustic  potash.     In  half  an  hour  the  color  becomes  brown. 

According  to  Mr.  Maurice  Scanlan,  wood-spirit  may  be  distinguished  from  acetone  (with 
which  it  appears  to  have  sometimes  been  confounded  in  medicine)  by  the  action  of  a  satu- 
rated solution  of  chloride  of  calcium,  which  readily  mixes  Avith  the  former,  but  separates  im- 
mediately from  the  latter. 

Wood-spirit  is  but  seldom  employed  now  in  the  arts,  as  it  is  generally  cheaper  and  more 
convenient  to  use  the  mixture  of  90  parts  of  spiiit  of  wine  with  10  parts  of  purified  wood- 
spirit,  which  is  now  permitted  by  Government  to  be  employed  free  of  duty  under  the  title 
of  "  methylated  spirit." 

The  theoretical  constitution  of  methylic  alcohol  is  of  course  represented  differently  by 
vaiions  chcmi.-its.  The  radical  theory  regards  it  as  the  hydrated  oxide  of  methyle.  The 
foimiila  being  C'''IPO,HO.  Another  theory  assumes  it  to  be  methylene,  (or  the  defiant  gas 
of  the  methyle  series,)  plus  two  cfiuivalents  of  water:  thus,  C'''IP,2H0.  But  the  most  con- 
venient method  of  viewing  it  is,  perhaps,  by  using  the  water  type,  and  considering  it  as  two 
eiiuivalents  of  water  in  which  one  atom  of  hydrogen  is  replaced  by  methyle,  thus : — 

H   J*^ 

This  method  of  regarding  it  has  the  advantage  of  enabling  us  to  give  a  direct  and  simple 
definition  of  alcohols  and  ethers.  Thus,  an  alcohol  may  in  this  manner  be  defined  as  two 
atoms  of  water  in  which  one  atom  of  hydrogen  is  replaced  by  an  electro-positive  radical, 
while  an  ether  is  to  be  looked  upon  as  two  atoms  of  water  in  which  both  atoms  of  hydrogen 
are  replaced  by  the  electro-positive  radical. 

Methylic  alcohol,  treated  with  solution  of  bleaching  powder,  yields  chloroform,  but  the 
resulting  product  is  not  so  fine  as  that  prepared  from  the  vinic  alcohol.  In  fact,  methylic 
alcohol  is  seldom  or  never  found  in  commerce  of  such  (unity  as  to  enable  good  chloroform 
to  be  prepared  by  the  action  of  chloride  of  lime.  Moreover  it  should  be  mentioned  that  so 
aciid  and  pungent  are  the  products  of  the  action  of  chlorine  on  the  bodies  accompanying 
crude  wood-spirit,  that  great  danger  would  be  incurred  in  using  a  chloroform  containing 
even  minute  traces  of  them.  The  following  eciuation  represents  the  action  of  the  chlorine 
of  the  ))!eachiiig  powder  on  wood-spirit: — 


QUmiKE.  943 

C=H^O-  +  4C1  =  C-ECr  +  2H0  +  HCl. 

■^ood-spirit.        Chloroform. 
Wood-spirit  unites  with  cliloride  of  calcium  with  such  energy  that  the  liquid  enters  into 
ebullition.     The  product  of  the  union  is  sufficiently  stable  to  endure  a  heat  considerably 
above  the  boiling-point  of  water,  without  giving  oft"  the  alcohol.     Water,  however,  destroys 
the  compound,  and  enables  the  spirit  to  be  distilled  away  on  the  water  bath. —  C.  G.  W 

Q 

QUrXIXE.  This  alkaloid  is  found,  together  with  four  other  alkaloids,  in  the  cinchona 
barks,  of  which  there  are  numerous  varieties,  some  containing  principally  quinine,  as  the 
C'a!isai/a  or  yellow  bark,  which  is  the  most  valuable  of  all  the  barks  on  that  account ;  others 
containing  principally  qitinidiiie  and  cincho7iine,v;']X\\  but  little  quinine. 

Quinine  is  the  principal  of  these  alkaloids,  and  is  now  manufactured  on  a  very  large 
scale  for  medicinal  purposes,  it  being  a  valuable  tonic  and  febrifuge. 

It  was  usually  prepared  from  the  C.  calisai/a,  but,  owing  to  the  scarcity  and  high  price 
of  this  bark,  several  of  the  inferior  barks  have  been  employed  in  its  manufacture,  and  on 
that  account  the  quinine  of  commerce  frequently  contains  some  of  the  other  alkaloids.  The 
sulpliate  is  the  only  salt  of  quinine  which  is  manufactured  ibr  commercial  purposes,  and  is 
generally  known,  though  improperly,  as  "  Disulphate  of  quinine." 

The  following  is  the  process  most  generally  followed  in  the  manufacture  of  this  salt : — 
The  coarsely-powdered  bark  is  digested  with  hot  dilute  sulphuric  or  hydrochloric  acid  for 
one  or  two  hours ;  the  liquor  is  strained  off,  and  the  bark  treated  with  a  fresh  portion  of 
still  more  dilute  acid  for  the  same  time.  This  process  may  be  repeated  a  third  time,  but 
the  litpior  then  obtained,  containing  so  little  quinine,  is  used  for  a  fresh  portion  of  bark. 
The  liquors  from  the  first  and  second  digestion  are  strained  and  mixed,  and  are  then  mixed 
with  lime,  magnesia,  or  carbonate  of  soda,  until  the  liquid  acquires  a  slight  alkaline  reaction, 
which  may  be  known  by  its  turning  red  litmus  paper  blue.  Owing  to  the  solubility  of  qui- 
nine, to  a  certain  extent,  in  milk  of  lime  and  chloride  of  calcium,  carbonate  of  soda  is  the 
best  to  be  used  for  this  purpose.  A  precipitate  is  formed,  which  is  separated  from  the  su- 
pernatant lifiuid  by  straining  through  a  cloth.  This  dark-colored  mass,  which  contains  the 
alkaloids,  coloring  matter,  some  lime,  and  some  sulphate  of  lime, — these  latter,  of  course, 
only  when  both  lime  and  sulphuric  acid  have  been  used  in  the  process, — is  treated  with 
boiling  ordinary  alcohol,  which  dissolves  the  alkaloids  and  coloring  matter.  This  solution 
is  tilteied,  and  the  greater  part  of  the  alcohol  removed  by  distillation,  when  a  brown  viscid 
mass  remains;  this  is  treated  with  dilute  sulphuric  acid,  till  the  solution  remains  slightly 
acid ;  this  solution  is  then  digested  with  animal  charcoal,  filtered,  evaporated,  and  allowed 
t  J  cool,  when  the  sulphate  of  quinine  crystallizes  out,  together  with  some  sulphate  of  quini- 
di;ie  or  cinchonine,  according  to  the  barks  which  have  been  employed ;  but,  owing  to  the 
greater  solubility  of  these  latter  salts  than  the  sulphate  of  quinine,  they  principally  remain 
in  the  mother  liquors.  When  pure  animal  charcoal  has  not  been  used,  the  sulphate  of  qui- 
nine is  likely  to  be  contaminated  with  some  sulphate  of  hme,  formed  by  the  action  of  the 
sulphuric  acid  on  the  lime  in  the  animal  charcoal ;  and  in  this  process  also  some  quinine 
is  likely  to  be  precipitated  by  the  lime  and  lost  in  the  animal  charcoal. 

In  order  to  separate  the  sulphate  of  quinine  thus  obtained  from  the  sulphates  of  quini- 
dine  and  cinchonine,  advantage  is  taken  of  the  greater  solubility  of  the  two  latter  salts,  as 
above  mentioned,  and  by  several  crystallizations  the  sulphate  of  quinine  may  be  obtained 
nearly  free  from  these  salts.  The  (piantity  of  sulphate  of  quinine  obtained  from  each 
pound  of  bark  of  course  varies  with  the  bark  used.  Some  of  the  best  cali.-<aya  bark  will 
yield  half  an  ounce  of  the  sulphate  from  every  pound  of  bark,  while  many  other  barks  which 
are  used  in  the  manufacture  of  sulphate  of  quinine  do  not  yield  a  cpiarter  of  an  ounce. 

A  process  has  been  patented  by  Mr.  Edward  Herring  for  the  manufacture  of  sulpliate  of 
quinine  without  the  use  of  alcohol,  and  it  yields  the  article  known  a^s  hospital  suli)liato  of 
quinine  at  the  first  crystallization  and  without  the  use  of  animal  charcoal.  The  following 
is  the  outline  of  the  process: — 

The  powdered  bark  is  boiled  in  solution  of  caustic  alkali,  (soda  preferred,)  wliich  removes 
the  useless  extractive  gummy  matters  and  coloiing  matter.  After  being  well  lioiled,  tlie 
bark  is  washed  and  pressed.  This  process  of  bailing  with  alkali,  &c.,  may  be  repeated,  if 
njce.ssary,  and  the  bark,  after  being  well  washed  and  ))iessed,  having  become  decolorized, 
is  boiled  witii  dilute  suljihuric  acid,  lieing  kept  constantly  stirred  whilst  boiling.  After  the 
separation  of  the  liquid,  the  bark  is  boiled  with  a  second  portion  of  dilute  acid,  and  some- 
times with  a  thii-d;  but  the  li(iuid  from  the  last  boiling  is  kept  to  lie  used  for  a  fresh  por- 
tion of  l>ark.  The  first  and  second  portions  are  mixed,  strained,  and  treated  with  soda, 
which  precipitates  the  alkaloids;  the  prccijjitate  is  washed  and  pressed,  and  then  digesteil 
with  dilute  sulphuric  acid,  which  di.^solves  the  alkaloids;  this  solution  is  evaporated  and  al- 
Inved  to  cool,  when  the  sulphate  of  quinine  crystallizes  out,  accompanied  with  some  sul- 


944  QUINIKE. 

pliatcs  of  quinidine  and  cinchonine,  if  the  bark  employed  contained  these  latter  alkaloids  in 
any  (luantity.  The  sulphate  of  (juinine  thus  obtained  is  diiod,  and  forms  the  unbleached  or 
hospital  (juinine.  When  the  sulpluite  of  quinine  is  required  (juite  pure,  this  is  treated  with 
pure  animal  charcoal,  and  subjected  to  two  or  three  further  crystallizations. 

It  will  be  seen  that  the  principal  points  in  this  process  are  the  extraction  of  the  coloring 
matter  by  the  caustic  alkali  and  the  use  of  pure  animal  charcoal  in  producing  the  perfectly 
white  sulphate,  which  prevents  completely  the  admixture  of  sulphate  of  lime  with  sulphate 
of  quinine. 

This  process  yields  from  80  to  90  per  cent,  of  the  quinine  contained  in  the  bark  em- 
ployed ;  and  to  obtain  the  remaining  10  or  20  per  cent,  the  blood-red  solutions  formed  by  boil- 
ing the  bark  with  the  caustic  alkali  are  treated  with  dilute  hydrochloric  acid  in  excess,  which 
retains  in  solution  any  alkaloids  that  are  present.  This  solution  is  strained  and  mixed 
with  lime.     The  precipitate  thus  formed  is  collected,  pressed,  dried,  and  powdered. 

It  is  then  digested  with  benzol,  or  any  solvent  which  is  not  a  solvent  of  lime.  These 
various  tinctures  or  preparations  are  well  agitated  with  dilute  sulphuric  acid,  which  xtracts 
the  quinine,  &c. ;  when  allowed  to  settle,  the  Lmzol,  oil  of  turpentine,  or  lard,  whichever 
has  been  used,  rises  to  the  surface.  The  acid  liquid  is  then  siphoned  off  and  evaporated, 
and  the  sulphate  of  quinine  ol)tained  from  it  is  purified  by  two  or  three  crystallizations, 
when  it  yields  a  salt  equal  to  that  obtained  by  the  first  process,  viz.  the  unbleached  or  hos- 
pital sulphate  of  quinine. 

The  sulphate  of  quinine  of  commerce  is  the  neutral  sulphate,  and  has  the  following 
composition:   . 

2C^"I1-^N-0',2HS0^+14  aq. 
When  pure  it  occur.s  as  white  spangles,  or  slender  needles,  which  are  slightly  flexible,  and 
possess  a  pearly  lustre  and  an  intensely  bitter  taste.  It  effloresces  in  the  air,  and  loses 
about  12  atoms  of  water.  {Baup.)  It  requires  for  solution,  740  parts  of  cold  water  and  30 
parts  of  boiling  water,  60  parts  of  alcohol  at  ordinary  temperatures,  and  much  less  of  boil- 
ing alcohol. 

Its  solution  in  acidulated  water  turns  the  plane  of  polarization  strongly  to  the  left,  and 
presents  a  blue  tint,  which  is  due  to  a  peculiar  refraction  of  the  rays  of  light  on  the  first 
surface  of  the  solution,  and  is  termed  fuorcxccncc  by  Professor  Stokes,  who,  as  well  as  Sir 
John  Herschel,  has  examined  the  cause  of  it,  the  latter  referring  it  to  epipolic  dispersion. 

Heated  to  212"  F.,  sulphate  of  quinine  becomes  luminous,  which  is  augmented  by  fric- 
tion, and  the  rubbed  body  is  found  to  be  charged  with  vitreous  electricity,  sensible  to  the 
electroscope.  It  fuses  easily,  and  in  that  state  resembles  fused  wax  ;  at  a  higher  tempera- 
ture it  assumes  a  red  color,  and  at  length  becomes  charred.  When  a  solution  of  quinine  is 
treated  with  chlorine  and  ammonia,  it  yields  a  bright  green  solution,  very  characteristic  of 
cjuiuine. 

Besides  the  neutral  sulphate,  there  exists  an  acid  sulphate,  or  hisulphate,  of  the  follow- 
ing composition : 

C'lP^N^OS  2HS0* -4- 1 6H0. 

It  is  formed  by  dissolving  the  neutral  sulphate  in  dilute  sulphuric  acid,  evaporating  and 
crystallizing.  It  crystallizes  in  rectangular  prisms,  or  silky  needles.  It  is  much  more  sol- 
uble in  water  than  the  neutral  sulphate,  requiring  only  11  j)arts  of  water  at  ordinary  tem- 
peratures to  dis.'iolve  it.     The  solution  reddens  blue  litmus  paper. 

It  fuses  in  its  water  of  crystallization,  and  at  212"  F.  loses  24-6  per  cent,  of  water. 
(Lichifj  and  Baup).  With  sulphate  of  sesquioxide  of  iron,  it  forms  a  double  salt,  which  crys- 
tallizes in  octahedra  resembling  those  of  alum. 

An  interesting  compound  of  iodine  and  bisulphate  of  quinine  has  been  discovered  by 
Dr.  Herapath,  which  crystallizes  in  large  plates,  and  by  reflected  light  presents  an  emerald 
green  color  and  a  metallic  lustre,  but  by  transmitted  light  appears  almost  colorless.  The 
point  of  interest  in  this  compound  is,  that  its  crystals  have  the  same  effect  upon  a  ray  of 
light  as  plates  of  tourmaline,  and  have  even  been  used  instead  of  this  latter  substance. 

Its  composhion  is:   C^"H"XW,P,2HSO^-hl0  aq. 

It  may  be  obtained  by  dissolving  the  bisulphate  of  quinine  in  concentrated  acetic  acid, 
and  adding  to  the  heated  li(|uid  an  alcoholic  solution  of  iodine,  drop  by  drop.  After  stand- 
ing a  few  hour.s,  the  salt  is  deposited  in  large  flat  rectangular  plates. 

Adulteration  of  su/pha/e  of  quinine. — Owing  to  the  high  price  of  sulphate  of  quinine, 
it  is  often  adulterated  wath  various  substances,  as  alkaline  and  earthy  salts,  boracic  acid,  su- 
gar, starch,  mannite  inargaric  acid,  salicine,  sulphates  of  cinchonine  and  quinidine ;  the  two 
latter  substances  will  be  found  in  most  of  the  commercial  sulphate  of  quinine,  and  are  not 
looked  upon  as  fraudulent  mixtures  when  present  only  in  small  quantities,  arising  then  from 
the  imperfect  })urification  of  the  sulphate  of  quinine.  Sometimes,  however,  sulphate  of 
cinchonine  is  present  in  large  quantities,  and  this  is  effected  by  briskly  stirring  the  solution 
from  which  the  sulphate  of  quinine  is  crystallizing,  when,  although  under  other  circum- 
stances the  suljjhate  of  cinchonine  would  remain  in  solution,  it  will  by  tliis  agitation  be  de- 
posited in  a  pulverulent  form,  together  with  the  sulphate  of  quinine.  No  doubt  this  fraud 
has  been  prMctis'-d  to  a  considerable  extent. 


:JJ 


RAILS.  945 

The  inorganic  substances  may  be  easily  detected  by  incinerating  some  of  the  suspect- 
ed salt,  when  they  will  be  left  as  ash.  When  some  of  the  suspected  sample  is  dissolved  in 
dilute  sulphuric  acid,  the  margaric  acid  would  remain  undissolved ;  if  we  then  add  to  the 
solution  a  slight  excess  of  baryta  water,  the  sulphuric  acid  and  quinine  will  be  precipitated ; 
the  excess  of  baryta  is  precipitated  by  carbonic  acid,  the  solution  is  then  boiled  and  filtered, 
when  the  sugar,  mannite,  and  saliciue  remain  in  solution,  and  may  be  detected  afterwards. 
The  presence  of  saliciue  may  be  detected  directly  in  sulphate  of  quinine  by  the  addition  of 
sulphuric  acid,  when  it  becomes  red  if  salicine  be  present.  Starch  is  detected  by  solution 
of  iodine,  witii  which  it  forms  a  deep  blue  compound.  Boracfc  acid  is  dissolved  by  alcohol, 
and  is  recognized  by  the  green  tinge  given  to  the  fiame  of  the  ignited  alcohol.  For  the  dis- 
covery of  cinchonine,  several  processes  have  been  proposed.  The  one  most  generally  adopt- 
ed, and  perhaps  the  best,  is  that  known  as  Liebig's  process,  which  depends  on  the  difference 
of  solubility,  in  ether,  of  quinine  and  cinchonine.  It  consists  in  putting  into  a  test  tube  10 
grains  of  the  sulphate  of  quinine  with  120  grains  of  ether,  then  adding  10  or  20  drops  of 
caustic  ammonia  ;  it  is  then  briskly  shaken.  If  the  sulphate  of  quinine  under  examination 
contains  no  cinchonine,  we  obtain  two  layers  of  liquids,  the  one  of  water  containing  sulphate 
of  ammonia,  and  the  other  ether  holding  the  quinine  in  solution ;  if  the  salt  contained  cin- 
chonine, this  would  remain  suspended  at  the  surface  of  the  watery  layer.  The  same  process 
will  detect  quinidine  also  when  present  in  quantities  exceeding  10  per  cent,  of  the  sulphate 
of  quinine ;  but  the  great  distinction  between  quinine  and  quinidine  is  their  deportment 
with  oxalate  of  ammonia,  this  reagent  causing,  in  a  solution  of  sulphate  of  quinine,  a  pre- 
cipitate of  oxalate  of  quinine;  whereas,  the  oxalate  of  quinidine  being  very  soluble  in  water, 
no  precipitate  is  formed  by  the  addition  of  oxalate  of  ammonia  to  a  solution  of  its  salt. 

Determination  of  the  quantity  of -quinine  in  samples  of  cinchona  harks. 

In  commerce  the  value  of  a  cinchona  bark  depends  on  the  quantity  of  cry.5<a//i3rt6^e  qui- 
nine which  it  will  yield ;  it  is  therefore  not  sufficient  to  determine  the  amount  of  quinine 
which  it  contains,  as  the  whole  of  this  may  not  be  convertible  into  crystallizable  sulphates. 
In"brder  to  be  accurate  not  less  than  a  pound  of  bark  should  be  used,  and  even  then  the  re- 
sult is  often  from  \\X\  to  Jth  less  than  can  be  obtained  on  the  large  scale,  where  the  loss  in 
the  process  is  much  less  in  proportion.     (Pereira). 

Several  processes  have  been  employed  for  determining  the  quantities  of  alkaloids  in  cin- 
chona barks. 

Perhaps  as  good  a  process  as  any  is,  to  exhaust  a  known  quantity  of  bark  by  boiling 
with  dilute  acid ;  the  solution  is  filtered,  and  the  residue  washed,  the  washings  being  added 
to  the  other  liquid ;  it  is  then  digested  with  pure  animal  charcoal,  the  solution  again  filtered, 
and  the  alkaloids  precipitated  by  carbonate  of  soda ;  they  are  then  collected,  dried,  and  di- 
gested with  ether  to  separate  the  quinine ;  after  the  evaporation  of  the  ethereal  solution, 
the  quinine  is  dissolved  in  dilute  sulphuric  acid,  the  solution  is  evaporated,  exactly  neutral- 
ized by  ammonia,  and  allowed  to  cool,  when  the  sulphate  of  quinine  crystallizes,  which  is 
collected,  dried,  and  weighed ;  the  quantity  of  the  mother  liquor  being,  of  course,  a  cold 
saturated  solution  of  sulphate  of  quinine,  and  knowing  the  solubility  of  sulphate  of  quinine 
in  water,  the  quantity  remaining  in  the  solution  may  be  determined  and  added  to  the  for- 
mer weight. — H.  K.  B, 

R 

RAILS.  The  manufacture  of  iron  rails  has,  with  the  extension  of  our  railway  system, 
increased  in  a  remarkable  manner.  This  is,  however,  rather  a  suliject  for  a  treatise  on  me- 
chanical engineering,  than  for  a  Dictionary  of  Manufactures.  A  short  notice  only  will 
therefore  be  given. 

In  1820,  Mr.  Birkinshaw  patented  an  improvement  in  the  form  of  hammered  iron  rail. 
The  malleable  iron  rails  previously  used  were  bars  from  two  to  three  feet  long,  and  one  to 
two  inches  stjuare ;  but  either  the  narrowness  of  the  surface  produced  such  injury  to  the 
wheels,  or  by  increasing  the  breadth  their  cost  became  so  great,  as  to  exceed  that  of  cast 
iron,  which  consequently  was  preferred. 

It  was  to  remedy  these  defects  in  the  malleable  form,  and  at  the  same  time  to  secure  the 
same  strength  as  the  cast  iron, 
that  Mr.  Birkinshaw  made  his  5T8  580 

rails  in  the  form  of  prisms,  or     .^  _ i.  .  -= — ^-^ — nir:^^        ^^B 

similar  in  shape  to  the  cast-  g^fe^ — ^^' ;_       ~  --"-'  r^'^j^^-  —    ;iWI;^^*       ""W^^ 

iron  ones  of  the  most  approved  ^^^  r~^^  t 3  K 

character.     /'V//.  578  shows  a  H 

side  view  of  this  kind  of  rail;  579 

,/>>  579,  apian,  and /.7.  580,     ir^  M  r^ 

a  section  of  the  same  rail  cut     ^' _    — --,      J'^'" i':_'!!^ 

through  the  middle.  @  H  ig 

Vol.  III.— 60 


946 


EASP,  MECHANICAL. 


These  rails  are  made  by  passing  bars  of  iron,  when  red  hot,  through  rollers  with  indenta- 
tions or  grooves  in  their  peripheries,  corresponding  to  the  intended  shape  of  the  rails ;  the 
rails  thus  formed  present  the  same  surface  to  the  bearing  of  the  wheels,  and  their  depths 
being  regulated  according  to  the  distance  from  the  point  of  bearing,  they  also  present  the 
strongest  form  of  section  with  the  least  material.     See  Rolling  Mills. 

Malleable  iron  rails  are  now  always  employed.  An  objection  has  been  urged  against 
these  rails  on  the  ground  that  the  weight  on  the  wheels  rolling  on  them  expanded  their 
upper  surface,  and  caused  it  to  separate  in  thin  laminee.  In  many  of  our  large  stations  rails 
may  be  frequently  seen  in  this  state ;  layer  after  layer  breaking  off,  but  this  may  be  regard- 
ed rather  as  an  example  of  defective  manufacture  than  any  thing  else.  It  is  true.  Professor 
Tyndal  has  referred  to  those  laminating  rails,  as  examples  in  proof  of  his  hypothesis,  that 
lamination  is  always  due  to,  and  is  always  produced  by,  mechanical  pressure  upon  a  body 
which  has  freedom  to  move  laterally.  Careful  examination,  however,  convinces  the  writer 
that  whenever  lamination  of  the  rail  becomes  evident,  it  can  be  traced  to  the  imperfect 
welding  together  of  the  bars  of  which  the  rail  is  formed. 

The  weight  of  railway  bars  varies  according  to  section  and  length.  There  are  some  of 
40  pounds  per  yard,  and  some  of  80  pounds,  almost  every  railway  company  employing  bars 
of  different  weight.  Besides  flat  rails,  which  are  occasionally  still  used,  we  have  bridge  rails 
employed,  which  have  the  form  of  a  reversed  U-  These  have  sometimes  parallel  sides,  or, 
as  in  dovetail  rails,  the  sides  are  contracted.  The  n-'^ils  are  more  easily  manufactured 
than  the  I-rails,  the  difficulty  of  filing  the  flanges  not  being  so  great  as  in  the  latter  rail. 
Fig.  581  represents  the  old  rail,  and^^r.  582  Mr.  W.  H.  Barlow's  patent  rail,  which  is 

made  to  form  its  own  contin- 
5S1  58..  ^  uous  bearing.     In  section  this 

rail  somewhat  resembles  an  in- 
verted V,  with  its  ends  con- 
siderably turned  outwards. 
This  portion  forms  the  surface 
by  which  the  rail  bears  upon 
the  ballasting,  the  apex  of  the 
f\  being  foimed  with  flanges 
in  the  ordinary  form  of  rails  ; 
and  the  rail,  therefore,  beds 
throughout  on  the  ballast.  It 
can  be  very  easily  packed  up 
and  adjusted  when  out  of  place,  and  all  the  fittings  of  sleepers,  chairs,  and  keys,  are  done 
away  with,  nothing  being  rerjuired  besides  the  rails  themselves,  except  a  cross  or  tic-iod  at 
the  joints,  to  hold  them  at  the  proper  distance  asunder,  so  as  to  keep  the  gauge  of  the  line. 
RASP,  MECHANICAL,  is  the  name  given  by  the  French  to  an  important  machine  much 
used  for  mashing  beet-roots.     See  Sugar. 

RATTANS.  The  stems  of  the  Calamus  rotang,  of  C.  ritdentnvi,  and  various  species  of 
palms.  They  are  used  for  caning  chairs,  as  a  substitute  for  whalebone,  for  walking-sticks, 
and  many  other  purposes.  V<' e  imported  in  1858,  18,625,308  rattan  canes,  valued  at  £38,9GO. 
REFiNIXG  GOLD  AND  SILVER.  Since  the  object  of  this  book  is  to  treat  more 
especially  of  the  application  of  scientific  processes  to  commercial  undertakings,  it  would  be 
out  of  place  to  give  a  detailed  account  of  the  processes  ))y  which  gold  and  silver  are  refined, 
or  rendered  free  from  other  metals.  In  the  laboratory,  where  chemical  manipulation  has 
reached  a  great  way  to  perfection,  the  precious  metals  are  separated  by  nitric  acid  and  other 
agents,  but  the  processes  are  far  too  expensive  and  tedious  to  admit  of  being  used  upon  a 
large  scale. 

For  the  purposes  of  rendering  gold  containing  foreign  metals  sufBciently  pure  for  the 
operations  of  coining,  Mr.  Warrington  has  recently  described  a  process  by  which  fused  gold 
is  treated  with  black  oxide  of  copper,  with  a  view  to  oxidizing  those  metals  wliich  render 
gold  too  brittle  for  manufacture  into  coin.  Mr.  Warrington  proposes  to  add  to  fused  gold, 
which  is  found  to  be  alloyed  with  tin,  antimony,  and  arsenic,  It)  per  cent,  of  its  weifiht  of 
the  black  oxide  of  copper,  which,  not  being  fusible,  is  capable  of  being  stiiicd  up  with  the 
fused  mass  of  gold,  just  as  sand  may  be  stirred  up  with  mercury,  but  witli  this  groat  advan- 
tage, that  the  oxide  of  copper  contains  oxygen,  with  which  it  parts  readily  to  oxidize  any 
metal  having  a  greater  affinity  for  oxygen  than  itself  The  metals,  once  oxidized,  become 
lighter  than  the  fused  metal,  and  mixing  mechanically,  or  combining  chemically  with  the 
black  oxide  of  copper,  float  to  the  surface  and  are  removed.  In  the  execution  of  Mr. 
Warrington's  proposition,  it  is  imperative  to  use  crucibles  free  from  reducing  agents,  such 
as  carbon,  and  it  is  found  that  half  an  hour  is  sufficient  time  to  allow  the  contact  of  the 
oxide  of  copper  with  the  fused  gold. 

It  has  been  generally  stated  by  those  supposed  to  be  acquainted  with  the  subject,  that 
gold  containing  tin,  antimony,  and  arsenic  is  so  brittle  as  to  render  it  wholly  unfit  for  coin- 
ing.    Tills  requires  modification,  for  although  these  metals,  as  well  as  lead,  render  gold  so 


REFINING  GOLD  AND  SILVER.  947 

brittle  that  it  will  readily  break  between  tlie  fingers,  yet  it  is  not  true  to  say  that  it  renders 
gold  so  brittle  as  to  be  incapable  of  being  coined.  In  June  and  Jnly,  1859,  some  brittle 
gold,  to  the  extent  of  about  04,000  ounces,  passed  through  the  Mint.  The  bars  were  so 
brittle  that  they  broke  with  the  slighest  blow  from  a  hammer,  but  by  special  treatment  the 
gold  was  coined  into  the  toughest  coins  ever  produced.  It  may  now  be  stated  that  if  the 
system  of  manufacture  be  changed  to  suit  the  recjuirements  of  the  case,  gold  cannot  be 
found  too  brittle  for  the  purpose  of  coining.  This  is  simply  a  matter  of  fact,  but  the  ex- 
pense of  coining  brittle  gold  is  undoubtedly  very  great;  it  is  thereibre  wise  that  Mr.  War- 
rington's plan  should  be  adopted  for  all  gold  containing  the  volatile  metals  or  tin.  Osniium- 
iridium  does  not  render  gold  brittle.  Dr.  Percy  and  Mr.  Smith  have  dcmonstiated  tliat  all 
metallic  substances  found  in  commerce  contain  traces  of  gold,  whicli  can  be  separated  by 
carefully  conducted  chemical  processes,  and  it  is  Ibund  that  silver  is  peculiaily  liable  to  l>e 
in  alloy  with  gold,  and  gold  with  silver  ;  hence  a  process  of  refining  which  shall  cllbct  the 
separation  of  as  little  as  one  five-hundredth  part  of  gold  from  its  mass  of  silver,  is  a  matter 
of  the  utmost  commercial  importance. 

It  is  with  regret  that  it  is  stated  that  the  refineries  of  London  are  conducted  with  such 
secrecy  as  to  render  a  full  description  of  any  one  of  them  impossible,  while  the  ignorance 
which  will  induce  the  proprietors  of  these  estai)lishments  to  attempt  such  quietude  is  much 
to  be  pitied,  for,  except  so  far  as  regards  details  of  interior  arrangement,  their  processes 
are  as  well  known  and  understood  as  it  is  possible  for  any  manufacture  to  be. 

In  Paris,  (the  London  refiners  are  known  to  use  the  "  French  process,")  the  plan  adopted 
is  founded  on  the  fact,  that  at  a  high  temperature  sulphuric  acid  parts  with  one  equivalent 
of  its  o.xygen  to  oxidize  an  atom  of  a  metal,  while  the  atom  of  oxide  so  formed  at  once  com- 
bines with  another  atom  of  sulphuric  acid  to  form  a  sulphate.  The  atom  of  sulphuric  acid 
which  has  parted  with  its  atom  of  oxygen  passes  off  as  gaseous  sulphurous  acid. 

If  mercury  be  boiled  with  sulphuric  acid,  (commonly  called  oil  of  vitriol,)  it  is  found  that 
it  entirely  loses  its  metallic  existence,  and  assumes  the  form  of  a  dense  white  salt.  This 
change  takes  place  at  the  expense  of  the  sulphuric  acid,  and  is  shown  Ijy  the  following  eqtia- 
tion.  For  explanation  sake,  call  mercury  Hg,  and  sulphuric  acid  SO';  if  now  it  is  assumed 
that  one  part  or  atom  of  Hg  be  boiled  with  two  parts  or  atoms  of  SO'',  we  have  Hg  +  SO^ 
+  SO^,  and  for  elucidation  we  may  write  SO'  as  equal  to  SO'^  +  0,  then  we  have  Hg  -J-  0 
+  SO-*  +  SO^,  which,  under  the  influence  of  heat,  become  HgOSO'  -:|-  SO'^ 

a  white  salt.        pas. 

If  now  the  mind  substitutes  silver  for  mercury,  and  so  writes  Ag  instead  of  Ilg,  the 
whole  matter  will  be  understood.  The  silver  is  dissolved  in  sulphuric  acid  just  as  sugar 
would  in  water,  and  in  this  fact  we  have  avaluable  means  of  separating  it  from  gold.  If 
for  a  moment  one  imagines  a  mass  of  silver  alloyed  with  gold  to  be  represented  by  a  piece 
of  sponge  filled  with  water  and  frozen,  it  is  well  known  that  if  the  mass  be  warm  the  ice  is 
melted,  and  in  the  form  of  water  filters  from  the  sponge;  just  so,  if  a  mass  of  the  alloy  of 
the  precious  metals  be  boiled  in  sulphuric  acid,  the  silver  is  dissolved  or  washed  away,  leav- 
ing the  gold  in  the  form  of  a  sponge,  which,  as  it  becomes  exposed  to  the  bubbling  of  the 
acid,  is  detached  and  falls  to  the  bottom  of  the  vessel  in  which  it  is  boiled. 

If  by  assay  the  silver  to  be  refined  is  found  to  be  very  rich  in  gold,  it  is  better  to  fuse 
the  mass  with  more  silver,  so  as  to  produce  a  mass  containing  at  least  3  of  silver  to  1  of  gold, 
and  this  alloy,  in  its  fluid  state,  should  be  poured  into  cold  water,  by  which  the  falling 
stream  is  suddenly  chilled,  and  the  particles  become  what  is  technically  called  "granulated." 
The  stream  should  fall  some  distance  (not  less  than  2  feet)  through  the  air  before  it  reaches 
the  water,  that  the  coppor  (if  any  be  present)  may  be  as  much  as  possible  oxidized,  with  a 
view  to  saving  sulphuric  acid. 

In  all  cases  the  alloyed  metals  should  be  granulated,  because  the  extended  surface  of 
metal  presented  to  the  hot  acid  saves  much  time. 

Silver  containing  less  than  '/500  part  of  its  weight  of  gold  is  fotmd  not  to  pay  for  separa- 
tion, but  any  which  contains  this  amount  or  more  is  treated  as  follows:  — 

Vessels  of  platinum  were  formerly  used,  and  were  deemed  indispensable,  but  experi- 
ment has  proved  that  these  may  be  safely  re])laced  by  cast-iron  vessels;  in  both  cases  the 
i)oilcrs  or  retorts  aie  provided  with  tubes  passing  from  the  top  into  chambers  which  receive 
the  acid  gases  and  vapors. 

The  i)latinum  vessels  used  by  Mr.  Mathison  and  subsequently  by  I^Iessrs.  fJothschild  for 
many  years  arc  now  out  of  use,  but  as  .sketches  of  the  vessels  actually  used  cannot  be  ob- 
tained, it  is  deemed  wi.se  to  give  a  sketch  of  the  platinum  vessels,  which  weigh  823--10  troy 
ounces,  and  contain,  if  filled  to  tlic  neck,  8  gallons  of  water,  a  the  retort  or  boiler;  n  the 
head,  provided  with  a  tube  of  platinum,  n,  to  which.is  joined  at  the  time  of  >ise  a  long  tube 
of  lead.  C  is  a  tube  terminating  on  the  shoulder  of  tlie  boiler,  and  provided  with  a  lid,  anil 
is  of  service  to  allow  of  the  occasional  stirring  of  the  silver  during  solution,  and  of  the  addi- 
tion of  the  small  (piantity  of  acid  at  the  termination  of  tlie  chemical  action.  The  vcs.sels 
became  much  coated  with  gold,  which  was  removed  with  dilficulty  and  at  great  risk  of 
attacking  the  platinum.     The  sketches  (fi'i/a.  583,  584,  and  585)  are  1  in.  to  a  foot. 


943 


EEFINING  GOLD  AND  SILVER. 


According  to  convenience  and  requirements,  the  retort  or  boilers  may  be  multiplied  aa 
to  number,  but  about  5  or  6  would  seem  to  be  a  convenient  set  for  operations.     Indepen- 

583 


dently  of  the  smaller  prime 
cost  of  cast-iron  retorts  or 
boilers,  (now  used  in  place  of 
platinum,)  there  is  the  advan- 
tage of  being  able  to  use  acid 
which  is  not  free  from  im- 
purities, because  the  cost  of 
the  retorts  is  practically  not 
worth  consideration,  if  taken 
in  relation  to  the  extra  price 
which  must  be  paid  for  pure 
acid.  Besides  these  facts,  it 
is  found  that  owing  to  some 
influence  (is  it  chemical  or  catalytic  V)  which  the  iron  exerts,  less  acid  is  required  to  be  used 
in  proportion  to  the  precious  metals  than  was  used  when  platinum  vessels  were  believed  to 
be  necessary. 

A  charge  for  one  boiler  varies  from  1 1 30  to  1 300  troy  ounces  of  the  granulated  mixed 
j)rccious  metals,  and  is  heated  with  about  twice  or  twice  and  a  half  times  its  weight  of  sul- 
phuric acid  of  sp.  gr.  1'7047.  The  heat  is  gradually  raised  until  effervescence  takes  place, 
and  it  is  then  regulated  with  care,  while  at  last,  the  temperature  is  raised  nearly  to  the  boil- 
ing point.  As  in  the  case  of  mercury  so  in  the  case  of  silver,  it  is  better  not  to  rise  quite  to 
the  boiling  point,  else  sulphuric  acid  distils  off  with  the  escaping  sulphurous  acid.  According 
to  the  care  with  which  the  granulating  has  been  effected,  each  charge  is  heated  from  3  to  4 
hours.  When  the  elimination  of  sulphurous  acid  ceases  the  operation  is  known  to  be  ter- 
minated, and  chemical  examination  shows  that  exactly  equivalent  quantities  of  sulphate  of 
silver  and  sulphate  of  copper  are  formed  to  account  for  the  sulphuric  acid.  In  practice  the 
sulphurous  acid  is  frequently  lost,  although  in  all  refineries  it  should  be  used  for  the  recom- 
position  of  sulphuric  acid. 

Leading  from  the  top  of  the  boiler  or  retort  is  an  horizontal  leaden  tube  from  8  to  10 
yards  long,  terminating  in  a  leaden  chamber,  in  which  sulphuric  acid  and  sulphurous  acids 
accumulate  with  some  sulphate  of  silver  mechanically  carried  over  by  the  violence  of  the 
chemical  action.  It  is  found  that  the  acid  which  accumulates  in  this  leaden  chamber  has  a 
sp.  gr.  of  from  l-3S04to  1-4493.  The  reduced  strength  of  the  acid  from  1-T047  to  this 
point  is  readily  understood  if  the  fact  be  remembered  that  sulphuric  acid  is  really  a  com- 
pound of  anhydrous  sulphuric  acid  and  water,  and  that  only  the  anhydrous  sulphuric  acid  is 
concerned,  although  the  water  performs  the  friendly  part  of  leading  it  into  action  on  the 
silver ;  the  action  having  commenced,  the  water  is  done  with,  and  passes  off  with  the  sul- 
phurous acid  as  it  is  eliminated  ;  but  independently  of  this  cause,  it  is  found  that  sulphuric 
acid,  by  boiling,  parts  with  water,  and  concentrates  itself,  until  by  and  by  the  anhydrous 
acid  itself  distils  off,  and  when  this  is  seen,  it  is  at  once  known  that  the  operation  is  carried 
rather  too  far.  When  the  action  has  quite  terminated,  it  is  customary  to  add  to  each  boiler 
or  retort  fiom  CO  to  80  troy  ounces  of  sulphuric  acid  of  sp.  gr.  1-6656,  procured  from  the 
liquor  which  has  deposited  sulphate  of  copper,  (presently  described,)  then  to  pour  the  whole 
into  a  leaden  Ijoiler,  and  boil  it  for  a  few  minutes,  then  withdraw  the  fire,  and  allow  to  stand 
for  half  an  hour,  during  which  time  the  gold  is  precipitated.  The  object  in  adding  this 
amount  of  sulphuric  acid  is  to  form  a  clear  solution,  that  the  gold  may  be  enabled  to  settle 
to  the  bottom ;  water  could  not  be  added,  because  it  would  probably  cause  an  explosion  by 
the  heat  evolved  in  its  combination,  and  because  sulphate  of  silver  is  not  very  soluble  iu 
water,  while  it  is  soluble  to  a  very  large  extent  in  hot  sulphuric  acid.  At  the  end  of  half 
an  hour  the  clear  liquor,  containing  in  solution  the  silver  and  copperas  sulphates,  is  decant- 
ed and  mixed  with  so  much  water  as  shall  reduce  it  to  a  sp.  gr.  of  from  1-2080  to  1-2605, 
and  well  stirred.  Copper  plates  are  then  introduced,  while  the  solution  is  kept  hot  or  boil- 
ing by  a  jet  of  steam. 

The  silver  salt  is  decomposed  by  th(f  copper  plates,  and  the  copper  passes  into  solution 
as  sulphate  of  copper,  so  that  at  the  end  of  the  precipitation  the  solution  contains  the  copper 
of  the  original  alloy,  as  well  as  the  copper  which  has  been  used  to  precipitate  the  silver. 
The  silver  precipitates  or  falls  to  the  bottom  in  a  finely  divided  or  spongy  form,  and  it  is 
commonly  thought  that  the  whole  of  the  silver  is  thrown  down  when  a  portion  of  the  solu- 


REFINING  GOLD  AND  SILVER.  9il> 

tion  13  not  rendered  tnrbid  by  a  solution  of  chloride  of  sodium ;  but  in  the  presence  of  a 
strongly  acid  solution  this  test  is  not  to  be  relied  on  for  minute  quantities ;  therefore,  in 
some  refineries,  the  solution  is  allowed  to  rest  for  days  together  in  leaden  cisterns  in  which 
copper  plates  are  placed,  so  that  by  these  means  the  last  traces  of  silver  are  obtained. 

If  the  amount  of  gold  be  very  minute,  the  original  solution  is  well  stirred  and  then 
allowed  to  settle  for  some  time,  when  finely  divided  gold,  mechanically  mixed  with  crystals 
of  sulphate  of  silver  and  crystals  of  sulphate  of  copper,  is  found  at  the  bottom.  Tiiis  deposit 
is  boiled  with  water,  and  is  then  transferred  to  a  vessel  in  which  it  is  kept  hot,  and  is  brought 
into  contact  witli  suspended  copper  plates,  by  which  the  silver  is  rendered  metallic,  and  fall- 
ing to  the  bottom  of  the  vessel,  mixes  with  the  gold.  The  mixed  precipitate  of  silver  and 
gold  is  then  dried,  melted,  and  granulated,  and  treated  with  sulphuric  acid,  as  in  the  process 
already  described.  By  this  extra  process  the  gold  becomes  concentrated  by  the  removal  of 
the  silver,  and  is  then  thrown  down  in  larger  and  more  easily  collected  particles.  When 
the  gold  is  finely  divided  and  precipitates  slowly,  the  following  plan  is  sometimes  adopted : — 
The  whole  precipitate  containing  finely-divided  gold  mixed  with  sulphate  of  silver,  is  washed 
well  with  warm  water,  and  left  to  rest.  The  sulphate  of  silver  is  dissolved,  but  the  gold  set- 
tles to  the  bottom  of  the  vessel,  but  is  still  mixed  with  a  minute  quantity  of  sulphate  of 
silver.  It  is  drained  and  placed  in  the  retort  or  boiler  of  cast  iron,  and  boiled  with  sulphu- 
ric acid  ;  this  boiling  is  twice  repeated,  and  at  last  a  very  diluted  solution  of  sulphate  of  silver 
is  obtained ;  but  by  the  boiling  the  gold  has  assumed  a  form  which  enables  it  to  precipitate 
rapidly ;  in  fact,  the  flocculent  sponge  becomes  a  mass  of  dense  particles,  which  fall  readily 
to  the  bottom,  are  collected  and  well  washed,  to  free  them  from  silver,  and  are  then  dried 
ready  for  melting. 

The  solution  of  sulphate  of  silver  is  evaporated  in  leaden  vessels  by  the  agency  of  steam 
until  it  becomes  saturated,  and  is  then  allowed  to  stand  for  an  hour,  that  all  the  gold  may 
separate,  and  is  then  drawn  off  either  by  a  tap  placed  about  half  an  inch  from  the  bottom  of 
the  vessel,  or  by  a  siphon,  and  is  then  treated  with  copper  plates  as  already  detailed. 

In  all  cases  the  precipitated  spongy  silver  is  carefully  washed  to  free  it  from  sulphate  of 
copper,  and  dried  by  heat  or  by  hydraulic  pressure ;  but  if  dried  by  pressure  the  masses 
obtained  are  found  to  contain  from  8  to  10  per  cent,  of  water,  and  are  therefore  dried  by 
gentle  heat  to  avoid  the  breaking  up  of  the  masses,  from  the  sudden  formation  of  steam,  as 
well  as  to  save  the  chance  of  destroying  the  pot  of  Picardy  clay  in  which  the  silver  is  melt- 
ed when  it  has  been  dried. 

After  melting,  the  silver  is  found  to  retain  traces  of  gold,  which  are  so  minute  a.s  to  be 
overlooked,  since  the  cost  of  recovery  would  exceed  the  value  of  the  gold  to  be  recovered; 
but  the  silver  is  found  to  be  alloyed  with  from  5  to  6  thousandths  of  its  weight  of  copper, 
which  appears  to  be  left  in  the  form  of  sulphate,  notwithstanding  the  washings  to  which  the 
silver  has  been  subjected.  It  is  practically  impossible  to  wash  away  the  last  traces  of  sul- 
phate of  copper.  This  small  amount  of  copper  is  of  little  importance,  since  it  amounts  to 
but  5  parts  of  copper  alloyed  with  995  parts  of  silver,  yet  this  may  be  removed  by  fusion 
and  treatment  with  nitrate  of  potassa. 

During  the  whole  process,  even  if  copper  be  not  present  in  the  original  mass  of  metal  to 
be  refined,  it  is  to  be  observed  that  copper  plates  are  used  for  precipitating  the  silver ;  there- 
fore sulphate  of  copper  is  found  in  considerable  quantities,  and  as  this  salt  has  a  high  com- 
mercial value  as  giving  the  base  for  many  colors  used  in  painting  and  paper-hangings,  as 
well  as  for  agricultural  purposes,  it  becomes  desirable  to  obtain  this  salt  in  a  salable  form. 
The  solution  is  therefore  evaporated  to  a  sp.  gr.  of  r.S804,  and  allowed  to  cool,  when  crys- 
tals deposit ;  but  since  sulphate  of  cojiper  deposited  from  strongly  acid  solutions  is  mixed 
with  the  anhydrous  salt,  the  whole  mass  of  crystals  is  redissolved  in  warm  water,  and  allow- 
ed to  stand  in  leaden  vessels  about  6  ft.  long,  3  ft.  deep,  and  3  ft.  wide,  that  the  crystals 
may  deposit  slowly,  as  .slow  formation  produces  large  crystals,  which  are  more  easily  collected. 
The  sul|)hate  of  copper  is  represented  by  CuO,SO',5HO.  Tlie  mother  licpiors  are  evaporat- 
ed and  returned  to  the  works,  being  in  fact  free  sul[)huric  acid,  with  a  small  amount  of 
sulphate  of  copper  in  solution.  The  parts  of  the  hydraulic  presses  which  come  in  contact 
with  the  silver  at  the  time  of  pressing,  are  coated  with  a  compound  of  tin  and  lead,  hardened 
by  mixture  with  antimony.  Cast  iron  is  very  little  attacked  bj'  concentrated  sulphuric  acid, 
but  it  is  necessary  to  avoid  wrought  iron  in  any  shape,  and  copper  vessels  would  of  course 
be  rapidly  destroyed. 

The  floors  should  be  covered  with  lead  of  tolerable  thickness.  The  melting  pots  used 
in  France  are  made  of  Picardy  clay,  and  hold  from  220()  to  '2tiOO  Troy  ounces  of  silver. 
The  pots  cost  from  4(i.  to  ijd.  each,  and  if  dried  and  used  with  care,  very  seldom  crack  or 
Ijreak. 

The  total  cost  of  refining  silver  in  Paris,  inclusive  of  the  loss  by  melting,  is  stated  to  be 
IT)  centimes  for  32  Troy  ounces;  but  it  must  be  understood  that  the  loss  of  silver  by  melt- 
inir  is  absolutely  very  minute,  l)ecausc  the  (lues  are  swept,  and  the  sweepings  so  obtained 
an'  made  to  yield  the  silver  which  has  been  volatilized,  while  the  pots,  &c.,  are  ground  and 
maile  to  yield  their  absorbed  silver. 

In  the  event  of  the  mass  containing  much  copper  and  little  silver,  it  is  usual  to  granulate 


950 


RHODIUM. 


the  mas3  and  roa?t  the  granulated  particles  to  oxidize  the  copper ;  the  oxide  of  copper  is 
tlifii  dissolved  out  by  diluted  sulphuric  acid,  and  the  remaining  mass  of  silver,  with  a  smaller 
amount  of  copper,  is  treated  in  the  ordinary  way. 

If  the  gold  contains  platinum,  it  is  found  that  it  is  apt  to  retain  from  4  to  5  per  cent,  of 
silver,  which  must  be  .separated  by  mixing  the  precipitated  gold  with  about  a  fourth  of  its 
weight  of  anhydrous  sulphate  of  soda,  (which  is  preferred  to  sulphate  of  potassa,  on  account 
of  its  greater  solubility  in  water,)  and  to  moisten  tliis  ma.ss  with  concentrated  sulphuric  acid, 
using  about  (>  or  7  parts  of  acid  to  every  10  parts  of  sulphate  of  soda.  The  moistened  mass 
is  then  heated  till  sulphuric  acid  ceases  to  distil  off,  and  the  heat  is  then  raised  till  the  whole 
mass  melts;  and  by  extracting  the  sulphate  of  silver  and  sulphate  of  soda  the  gold  will  be 
found  to  contain  91»-4t)  parts  of  gold  iu  lOO'OO  parts;  but  if  the  process  be  repeated,  the 
gold  is  obtained  of  a  purity  of  9y"90. 

When  the  silver  has  been  removed,  the  gold  is  fused  with  nitre,  which  oxidizes  and  re- 
moves the  platinum ;  but  the  pota.sh  salt  formed  is  found  to  contain  gold,  so  that  the  gold 
and  platinum  are  obtained  from  the  potash  salt  mixed  with  fused  nitre  by  the  process  of 
cupcUation,  for  which  see  Assay. — (J.  F.  A. 

KIIODIUM.  The  following  remarks  from  a  recent  paper  by  Deville  and  Debray,  "On 
xmiie  /iropcrlies  of  the  so-called  jdatin  um  melafs,^^  are  full  of  interest.  These  chemists  prepare 
rhodium  by  fusing  platinum  residues  with  an  equal  weight  of  lead  and  twice  its  weight  of 
litharge.  When  the  crucible  lias  attained  a  bright  red  heat,  and  the  litharge  is  thoroughly 
liquid,  the  crucible  is  shaken  once  or  twice,  and  is  then  allowed  to  cool  slowly.  The  button 
of  lead,  which  contains  all  the  metals  in  the  residue  less  oxidizable  than  lead,  is  treated 
with  nitric  acid,  diluted  with  an  equal  volume  of  water,  which  removes  besides  the  lead  the 
copper  and  the  palladium.  The  insoluble  powder  which  remains  is  mixed  with  five  times 
its  weight  of  binoxide  of  barium,  weighed  exactly,  and  is  heated  to  redness  in  a  clay  crucible 
for  one  or  two  hours.  After  this  it  is  first  treated  with  water,  and  then  with  aqua  regia  to 
remove  the  osmic  acid.  When  the  liquor  has  lost  all  smell,  sufficient  sulphuric  acid  is  add- 
ed to  precipitate  the  baryta.  It  is  then  boiled,  filtered,  and  evaporated,  first  adding  to  it  a 
little  nitric  acid  and  then  a  great  excess  of  sal  ammoniac.  The  evaporation  is  carried  to 
dryness  at  212',  and  the  residuum  is  washed  with  a  concentrated  solution  of  sal  ammoniac, 
which  removes  all  the  rhodium.  When  the  washings  are  no  longer  colored,  the  liquor  is 
evaporated  with  a  great  excess  of  nitric  acid,  which  destroys  the  sal  ammoniac,  and  when 
only  the  salt  of  rhodium  is  left,  the  evaporation  is  finished  in  a  porcelain  crucible.  The  rho- 
dium salt  is  now  moistened  with  hydrosulphide  of  ammonia,  mixed  with  three  or  four  times 
its  weight  of  sulphur,  and  the  crucible  is  heated  to  blight  redness,  after  which  metallic  rho- 
dium is  left  in  the  crucible.  So  obtained  rhodium  may  be  considered  almost  pure,  after  it 
has  been  boiled  for  some  time,  first  in  aqua  regia,  and  then  in  concentrated  sulphuric  acid. 
To  obtain  it  perfectly  pure  it  must  l)e  melted  with  four  times  its  weight  of  zinc.  The  alloy 
is  treated  with  concentrated  hydrochloric  acid,  which  dissolves  most  of  the  zinc,  but  leaves 
a  crystalline  matter  which  is  really  an  alloy  of  rhodium  and  zinc  in  definite  proportions. 
This  is  dissolved  in  arpia  regia,  and  the  solution  is  treated  with  ammonia  until  the  precipitate 
first  formed  is  redis.solved.  The  solution  is  boiled  and  evaporated,  by  which  is  obtained  the 
yellow  .salt,  or  chloride  of  rhodium.  This  is  purified  by  repeated  crystallization,  and  then 
calcined  with  a,  little  sulphur,  l)y  which  means  rhodium  is  procured  absolutely  pure. 

Rhodium  melts  less  easily  than  platinum,  so  much  so  that  the  same  fire  which  will 
li(|uefy  ;5(H)  grammes  of  platinum  will  only  melt  40  or  50  grammes  of  rhodium.  It  is  not 
volatilized,  but  it  oxidizes  on  the  surface  like  palladium.  Less  white  and  lustrous  than  sil- 
ver, it  ha.s  about  the  same  appearance  as  aluminum.  When  perfectly  pure  it  is  ductile  and 
malleal)le,  at  least  after  fusion.     Its  density  is  12'1. 

The  alloys  of  rhodium,  those  at  least  which  have  been  examined,  are  true  chemical  com- 
binations, as  is  shown  by  the  high  temperature  developed  at  the  moment  of  their  formation. 
The  alloy  with  zinc  already  described  resists  the  action  of  muriatic  acid,  but  in  contact  with 
air  and  the  odd  there  is  soon  a  well-marked  rose  coloration  which  reveals  an  oxidation  of 
the  two  metiils  under  the  double  influence  of  the  air  and  acid.  The  alloy  with  tin  is  crys- 
tallized, lilack,  brilli.mt,  and  fusible  at  a  very  high  tempei'ature. 

RIFLE.S.  RiKi.ED  Okdnance  and  [{kvolveks. — Under  the  head  of  Fire-Arms,  vol.  i., 
in  addition  to  the  general  description  of  the  manufacture  of  the  ordinary  musket  barrel  and 
the  twisted  barrel,  with  that  of  gun  locks  of  various  kinds,  there  is  an  account  of  the  mode 
adopted  for  rifling  liarrels,  and  of  the  nK'tlif)ds  in  u.^e  at  the  Royal  Manufactory  at  Enfield. 
Beyond  this,  the  carabine  d  Hffe,  the  Minie  ritle,  with  the  needle  musket,  or  zundnadelge- 
wher  of  the  Prussi  m.s,  were  severally  noticed;  and  some  infoiniation  given  respecting  the 
more  recent  Enfield  rifle.  So  many  and  so  inqxM-tant  have  been  the  improvements  which 
have  been  introduced  that  it  is  necessary  to  return,  somewhat  more  fully,  to  the  considera- 
tion of  this  subject.  Fire-arms  are  rifled  to  give  rotation  to  the  projectile  round  its  axis 
of  progression,  in  order  to  insure  a  regular  and  steady  flight.  The  only  practical  method 
of  doing  this,  iiitherto  adopted,  has  been  to  make  the  barrel  of  a  fire-arm  of  such  a  shape  in 
its  interior,  that  the  projectile,  while  being  propelled  from  the  breach  to  the  muzzle,  may 
receive  a  rotatory,  combined  with  a  forward,  motion. 


KIFLES. 


951 


Enfield  Rifle. — The  dimensions,  &c.,  of  the  long  Enfield  is  given  in  the  article  already 
referred  to.     The  barrel  of  the  short  Enfield  is  only  2  ft.  9  in.  in  length. 

The  material  for  the  barrels  of  the  arms  made  at  the  Government  works  is  brought  to 
tlie  factory  in  slabs,  half  an  inch  thick,  and  12  in.  long  by  4  in.  broad.  These  slabs  of 
iron  are  carefully  forged,  to  insure  the  crossing  of  the  fibres  of  the  iron.  They  are  heated, 
and  first  bent  into  a  tubular  form  ;  they  are  then  heated  again,  and  wliile  white  hot,  passed 
between  iron  rollers,  which  weld  the  joining  down  the  middle,  and  at  the  same  time  lengthen 
the  tube  nearly  three  inches.  This  heating  is  several  times  repeated,  and  the  processes 
of  loIIing  continued  until  the  barrel  assumes  the  form  of  a  rod,  about  4  ft.  long,  having  a 
bore  down  the  centre  about  J  of  an  inch  in  diameter. 

The  muzzles  are  then  cut  off,  the  "butts"  made  up,  and  the  process  of  welding  on  the 
nipple  lump  is  begun.  This  operation  requires  much  care,  and  it  is  executed  with  great 
quickness  and  skill  by  the  trained  workmen.  The  barrels  pass  from  the  smithy  to  the  bor- 
ing department.  The  barrels  are  arranged  horizontally,  and  the  first-sized  borer  is  drawn 
upward  from  the  breech  to  the  muzzle.  The  second  boring  is  effected  with  rapidity ;  but 
the  third  slowly;  and  after  the  fourth  boring  the  barrel  is  finished  to  within  the  ^/looo  of  an 
inch  of  its  proper  diameter.  The  outside  is  ground  down  to  its  service  size,  and  the  barrel 
is  straightened ;  it  is  then  tested  by  a  proof-charge  of  1  oz.  of  powder  and  1  ball.  The  next 
step  is  to  fit  the  nipple-screw,  nipple,  and  breech-pin.  The  barrel  is  then  bored  for  the  fifth 
time,  and  it  passes  to  the  finishing  shop.  In  lifling  the  Enfield,  each  groove  is  cut  sepa- 
rately, the  bit  being  drawn  froni  the  muzzle  to  the  breech.  The  depth  of  the  rifling  isO'5  at 
the  muzzle,  and  0'13  at  the  breech,  and  the  width  of  each  groove  is  Vie  of  an  inch.  After 
rifling  the  barrel  is  again  proved,  with  half  an  ounce  of  powder  and  a  single  ball.  It  is 
then  sighted,  trimmed  olf,  milled,  levelled,  browned,  gauged,  and,  at  last,  finished  so  per- 
fectly, that  the  steel  gauge  of  '577  of  an  inch  passes  freely  through,  while  that  of  '580  will 
not  enter  the  muzzle. 

The  system  of  rifling  by  grooves  is  the  plan  which  has  been  generally  employed,  and 
many  experiments  with  different  numbers  of  grooves,  some  of  varying  depths,  being  deeper 
at  the  breech,  and  with  different  turns,  some  increasing  towards  the  muzzle,  have  been 
tried,  and  thought  advantageous,  at  various  times.  The  Enfield  rifle  has  three  grooves, 
with  a  pitch  of  6  ft.  6  in.,  so  that  the  bullet  receives  half  a  turn  round  its  axis  while  moving 
through  the  barrel,  the  length  of  which  is  3  ft.  3  in.  The  bullet  is  cylindro-conchoidal ;  it  is 
wi'apped  in  paper,  and  made  of  such  a  diameter  as  to  pass  easily  down  the  barrel.  It  re- 
quires very  pure  lead,  to  allow  of  its  being  properly  expanded,  or  "  upset,"  by  the  explosion, 
and  is  diiven  partly  against  the  original  portions  of  the  bore,  called  the  lands,  and  partly  in 
the  form  of  raised  ribs,  is  forced  into  the  grooves,  whose 
spiral  shape  gives  the  required  rotation.  The  Enfield  bullet 
is  sho\^n  in  the  annexed  figure.  It  is  conical  in  shape,  and 
has  its  back  end  recessed  for  the  insertion  of  a  box-wood  plug. 
Tliis  plug,  driven  forward  at  the  first  shock  of  the  explosion 
of  gunpowder,  expands  the  lead  until  it  fills  the  grooves  at 
the  breech,  {fig.  586.) 

The  prime  cost  of  a  finished  Enfield  rifle  is  stated  to  be 
about  £2  5.s\  ;  and  from  1,500  to  1,800  rifles  per  week  are  at 
present  made  at  the  Enfield  rifle  factory. 

W/nt worth' n  R'tfle. — This  fire-arm,  and  the  principles  on 
which  it  is  constructed,  cannot  be  better  described  than  by 
adopting  to  a  great  extent  the  words  of  the  inventor : — In  the 
system  of  rilling  which  I  have  adopted,  the  interior  of  the  bar- 
rel is  hexagonal,  and  instead  of  consisting  partly  of  non-effect- 
ive Icvuh,  and  partly  of  grooves,  consists  of  elfective  rifling  sur- 
faces. The  angular  corners  of  the  hexagon  are  always  rounded, 
as  shown  in  section,  fig.  588,  which  shows  a  cylindrical  bullet 
in  a  hexagonal  barrel.  The  hexagonal  bullet,  which  is  pre- 
ferred to  the  cylindrical  one,  although  either  may  be  used, 
is  shown  in  fig.  587.  Supposing,  however,  that  a  bullet  of 
a  cylindrical  shape  is  fired,  when  it  begins  to  expand  it  is 
driven  into  the  recesses  of  the  hexagon,  as  shown  mfig.  588. 
It  thus  adapts  itself  to  the  curves  of  the  spiral ;  and  the  in- 
clined sides  of  the  hexagon  offering  no  direct  resistance,  ex- 
pansion is  easily  elfected.  With  all  expanding  bullets  proper 
powder  must  be  used.  In  many  cases  this  kind  of  bullet 
has  failed,  owing  to  the  use  of"  a  slowly-igniting  powdt'r, 
which  is  desirable  for  a  hard  metal  projectile,  as  it  causes  less 
strain  upon  the  piece ;  but  is  imsuitablc  with  a  .soft  metal 
expanding  projectile,  for  which  a  (juickly-igniting  powder  is 
absolutely  requisite  to  insure  a  complete  expansion,  which  will  fill  the  bore ;  unless  this  is 


952 


RIFLES. 


done  the  gases  rush  past  the  bullet,  between  it  and  the  barrel,  and  the  latter  becomes  foul, 
the  bullet  is  distorted,  and  the  sliooting  must  be  bad.  If  the  projectile  be  made  of  the  samo 
hexagonal  shape,  externally,  as  the  bore  of  the  barrel  internally,  that  is,  with  a  mechanical 
fit,  metals  of  all  degrees  of  hardness,  from  lead,  or  lead  and  tin,  up  to  hardened  steel,  may 
be  employed,  and  slowly-igniting  powder,  like  that  of  the  service,  may  be  used.  As  we 
have  already  stated,  the  Entield  rifle  has  one  turn  in  C  ft.  6  in.  ;  that  is,  the  bullet  rotates 
once  on  its  axis,  in  passing  over  this  space.  This  moderate  degree  of  rotation,  according  to 
Mr.  Whitworth,  only  admits  of  short  projectiles  being  used,  as  long  ones  turn  over  on  issu- 
ing fi'om  the  barrel  ;  and  at  long  ranges,  the  short  ones  becomes  unsteady.  With  the  hex- 
agonal barrel  much  (luicker  turns  are  used;  and  "I  can  fire  projectiles  of  any  required 
length,  as,  with  the  quickest  that  may  be  desirable,  they  do  not  'strip.'  I  made  a  short 
barrel,  with  one  turn  in  the  inch  (simply  to  try  the  effect  of  an  extreme  velocity  of  rotation) 
and  found  that  I  could  fire  from  it  mechanically-fitting  projectiles,  made  of  an  alloy  of  lead 
and  tin  ;  and  with  a  charge  of  35  grains  of  powder  they  penetrated  through  7  inches  of  elm 
planks." 

"  For  an  ordinary  military  b^rel  39  inches  long,  I  proposed  a  •45-inch  bore,  with  one 
turn  in  20  inches,  which  is  in  my  opinion,  the  best  for  this  length.  The  rotation  is  suffi- 
cient, with  a  bullet  of  tlie  requisite  specific  gravity,  for  a  range  of  2,000  yards.  The  gun 
responds  to  every  increase  of  charge,  by  giving  better  elevation,  from  the  service  charge  of 
70  grains  up  to  120  grains;  this  latter  charge  is  the  largest  that  can  be  effectually  con- 
sumed, and  the  recoil  then  becomes  more  than  the  shoulder  can  conveniently  bear  with  the 
weight  of  the  service  musket." 

The  advocates  of  the  slow  turn  of  one  in  6  ft.  6  in.,  consider  that  a  quick  turn  causes  so 
much  friction  as  to  impede  the  progress  of  the  ball  to  an  injurious,  and  sometimes  danger- 
ous, degree,  and  to  produce  loss  of  elevation  and  range  ;  but  Mr.  Whitworth's  experiments 
show  the  contrary  to  be  the  case.  The  effect  of  too  quick  a  turn,  as  to  friction,  is  felt  in 
the  greatest  degree  when  the  projectile  has  attained  its  highest  velocity  in  the  barrel,  that 
is  at  the  muzzle,  and  is  felt  in  the  least  degree  when  the  projectile  is  beginning  to  move,  at 
the  breech.  The  great  strain  put  upon  a  gun  at  the  instant  of  explosion  is  due,  not  to  the 
resistance  of  friction,  but  to  the  vis  incrtixe  of  the  projectile  which  has  to  be  overcome.  In 
a  long  barrel  with  an  extremely  quick  turn,  the  resistance  offered  to  the  progress  of  the 
projectile  as  it  is  urged  forward  becomes  very  great  at  the  muzzle,  and  although  moderate 
charges  give  good  results,  the  rifle  will  not  respond  to  increased  charges  by  giving  better 
elevation.     If  the  barrel  be  cut  shorter,  an  increase  of  charge  then  improves  the  elevation. 

Rifled  Ordnance.  See  Artillery.  Whitworth's  system  of  rifling  is  equally  applicable 
to  ordnance  of  all  sizes,  the  principle  of  construction  is  simple,  and  the  extent  of  bearing 
afforded  by  the  rifling  surfaces  provides  amply  for  the  wear  of  the  interior  of  the  gun  ;  any 
requisite  allowance  for  windage  may  be  made  at  the  same  time  that  the  projectile  is  kejit 
concentric  with  the  bore.  We  have  not  space  to  enter  on  any  examination  of  the  rifled  ord- 
nance manufactured  by  Mr.  Whitworth,  which  is  in  principle  the  same  as  the  rifle  which  we 
have  briefly  described.  The  extraordinary  results  obtained  in  the  trials  of  Whitworth's 
guns  have  been  so  remarkable,  that  as  a  matter  of  curious  history  it  appears  important  to 
preserve  a  statement  of  these  trials,  as  made  at  Southport,  which  were  witnessed  by  many 
of  the  most  eminent  authorities. 

Our  space  will  not  admit  of  our  giving  tables  of  all  the  experiments  made ;  we  h.ave, 
therefore,  cho.sen  those  which  give  the  best  and  most  interesting  results.  We  have  in  each 
table  given  the  distance  of  every  shot  fired  in  the  series  or  group  forming  the  particular 
experiment.  In  some  cases  average  distances  are  calculated  from  the  ascertained  centre  of 
the  group  of  shots  fired,  and  arc  taken  longitudinally  and  laterally.  This  is,  in  fact,  apply- 
ing to  the  horizontal  area  in  which  the  shots  fell  the  same  principles  on  which  the  "  figure 
of  merit"  is  determined  on  the  vertical  targets  at  the  Hythe  School  of  Musketry.  This 
method  of  calculation  is  the  most  accurate,  for,  as  the  gun  was  always  laid  for  the  line  of 
fire,  and  no  alteration  was  made  in  its  direction  during  the  firing  of  a  particular  group,  a 
certain  amount  of  deviation  would  be  given  to  all  the  shots  by  the  wind.  Therefore,  the 
closer  the  shots  lay,  the  better  was  the  shooting,  without  regard  to  the  general  deviation 
from  the  line  of  fire,  which  might  be  greater  or  less  according  to  the  direction  and  force  of 
the  wind. 

After  this  digression  we  return  again  to  the  Rifles.  A  professional  writer,  well  qualified 
to  judge  of  the  matter  on  which  he  wrote,  has  made  some  striking  remarks  on  the  Whit- 
worth rifle  in  the  Mechanic^''  Magazine.  After  pointing  out  the  small  importance  of  a  high 
prime  cost  in  the  case  of  so  durable  a  weapon  as  the  rifle  in  question,  be  refers  to  the 
strength  of  the  metal  used. 

In  illustration  of  its  great  strength,  this  fact  is  quoted :  Mr.  Whitworth  put  into  a  rifle 
barrel,  one  inch  in  diameter  at  the  breech,  with  a  bore  of  0'49inch,  a  leaden  plug  18  incl.ei 
long,  as  tightly  as  it  could  be  driven  home  upon  the  charge.  It  was  fired  with  an  ordinary 
charge  of  powder,  and  the  leaden  i)lug  being  expanded  by  the  explosion  remained  in  the 
barrel,  the   gases  generated  i)y  the  gunpowder  all  jtassing  out    through    the    touch-hole. 


RIFLES. 


953 


With  such  strength  great  durability  must  of  necessity  co-exist,  unless  the  quick  turn  of  the 
rifling  should  tend  to  its  rapid  deterioration.  But  this  is  not  the  case,  Mr.  Longridge's  elab- 
orate investigations  having  proved  that  the  amount  of  the  force  expended  upon  the  rifling 
of  the  Whitworth  rifle  scarcely  exceeds  two  per  cent,  of  the  total  force  of  the  powder. 

Table  of  Experiments. 


3-PouNDER  Gun,  9  shots  fired  at  an  eleva- 
tion of  3°,  charge  7i  oz.,  Feb.  22. 


EnDge 

in 
yards. 


Deviation 

from  line 

of  fire  in 

yards. 


Average  longitudinal 
deviation,  11^  yards ; 
average  lateral  devia- 
tion, f  yard ;  meas- 
ured from  the  centre 
of  9  shots  fired. 


1552  + 

1568  ,        2 

1573  .  i 

1575  I  t 

1577  i 

1588  1 

1589  0 
1593  0 
1607  1         i 

3-PocNDER  GcN,  10  shots,  at  an  elevation 
of  10°,  charge  7^  oz.,  Feb.  23. 


Average  longitudinal 
deviation,  48  yards ; 
average  lateral  devia- 
tion 9  7  yards  from 
the  centre  of  the 
group. 


3865 

n 

3888 

10 

3871 

13 

3913 

12 

3831 

13 

381G 

12 

3717 

11 

3850 

8 

3763 

n 

3905 

2i 

3-Pou> 

DER 

GcN,  1 

of  2 

u",  charge 

6650 

22 

right 

6614 

21 

6655 

24 

6702 

17 

6646 

17 

6704 

17 

6690 

19 

6581 

19 

6692 

18 

6645 

7 

6712 

7 

23. 


Average  longitudinal 
deviation,  33  yards; 
average  lateral  devia- 
tion 4  yards;  taken 
from  the  centre  of 
group. 


3-PocxnER  GcN,  5  shots,  at  an  elevation 
of  35°,  charge  8i  oz.,  Feb.  16. 


Range 

in 
yards. 


9453 
9503 
9611 
4965 
9688 


Deviation 

from  line 

of  fire  in 

yards. 


52  right 
72     " 
89     " 
31      " 
35     " 


Average  longitudinal 
deviation,  81  yards; 
average  lateral  devia- 
tion 19  yards  from 
centre  of  the  group. 


12-PorNDER  GcN,  10  shots,  at  an  eleva- 
tion of  5',  charge  1^  lb. 


2354 

n  right 

2352 

2i     " 

2351 

3       " 

2348 

2       " 

Average     longitudinal 

2347 

4       " 

deviation,  16  yards; 

2343 

2i     " 

averatrc  lateral  devia- 

2337 

ileft 

tion   from  centre    of 

2334 

2   right 

group,  1  yard. 

2304 

5       " 

2288 

2       " 

12-PonNDER  GcN,  4  shots,  at  an  elevation 
of  7°,  charge  If  lb.,  Feb.  21. 


3098 
3078 
3107 
3107 


0 
ileft 
\\  right 
0 


Greatest  difference  in 
range,  29  yards ; 
greatest  difference  in 
width,  Ij  yard. 


SO-PorNRER  GcN,  4  shots,  at  an  elevation 


of  7°,  charge  14  lb. 


3482 
3487 
3498 
3503 


H  right 
6^     " 
6       " 
41     " 


Greatest  difference  in 
range,  21  yards; 
greatest  difference  in 
width,  I5  yard. 


Perhaps  the  most  remarkable  testimony  which  has  been  borne  to  the  merits  of  this  rifle 
is  that  of  General  Hay,  the  director  of  musketry  instruction  at  Ilythe.  After  admitting 
tlic  superiority  of  the  Whitworth  to  the  Enfield  in  point  of  accuracy.  General  Hay  said 
there  was  a  peculiarity  about  the  Whitworth  small-bore  rifles  which  no  other  siiniliar  arms 
had  yet  produced — they  not  only  gave  greater  accuracy  of  firing,  but  treble  power  of  pen- 
etration. For  special  purposes,  any  description  of  bullet  could  be  used,  from  lead  to  steel. 
The  Whitworth  rifle,  with  a  bullet  one-tenth  of  tin,  penetrated  35  planks,  whereas  the  Enfield 
rifle,  with  which  a  soft  bullet  was  necessary,  only  p(>netratcd  12  planks.  He  had  found  tiiatat 
a  range  of  800  yards,  the  velocity  added  to  tlie  hardened  bullet  gave  a  power  of  penetration 
in  the  proportion  of  17  to  4  in  favor  of  the  Wliitwortli  rifle.  This  enormous  jjenctratiou  is 
of  the  highest  importance  in  a  military  weapon,  in  filing  through  gabions,  sandbags,  and 
other  artificial  defences.  Mr.  Bidder,  President  of  the  Institution  of  Civil  Engineers,  says, 
tlie  Whitworth  small-bore  rifl*,  fired  with  common  sporting  powder,  would  never  foul  so  as 
to  render  loading  difficult.  He  had  himself  fired  100  rounds  one  day,  60  rounds  the  next, 
then  40  rounds,  and  so  on,  and  left  the  gun  witliout  being  cleaned  for  ten  days,  when  it  fired 
as  well  as  it  did  on  the  first  day.     The  words  of  Mr.  Whitworth  aa  to  the  application  of  his 


954  EITLES. 

principle  to  the  Enfield  weapon  must  be  quoted  in  answer  to  the  objections  of  cost,  &c.,  uro-ed 
against  it.  "  With  regard  to  the  cost  of  my  rifled  musket,  which  has  been  stated  to  be  an 
impediment  in  the  way  of  its  adoption  for  the  service,  I  may  state  that  there  would  be  no 
diliiculty  in  adapting  the  machinery  and  plant  already  in  operation  at  Enfield,  or  any  requi- 
site portion  of  it,  for  making  rifles  on  my  system.  The  change  would  not  cause  an  increase 
in  the  manufacturing  expenses;  and,  supposing  the  quality  of  the  workmanship  and  the 
materials  to  remain  the  same,  the  advantages  aiising  from  the  use  of  my  bore  and  turn,  and 
hard  metal  projectiles,  would  double  the  efficiency  of  the  rifle  without  increasing  the  cost." 

Amongst  arms  requiring  some  notice  from  us,  the  more  remarkable,  as  involving  some 
excellence  in  construction,  or  peculiarity  in  principle,  are  the  following : — 

CoWs  Repeating  Rifle. — This  weapon  is  constructed  mainly  on  the  principle  which  was 
introduced  by  Colonel  Colt,  in  his  "  revolvers,"  to  be  noticed  presently.  The  Secretary  of 
War  of  the  United  States  reports  as  follows  on  this  arm,  which  is  shown  in  fig.  589,  and  in 
section  fig.  590.  Fig.  591  is  a  vertical  section  of  the  revolving  barrels,  and  fig.  592  the 
wiping  rod. 

"  The  only  conclusive  test  of  the  excellence  of  the  arms  for  army  purposes  is  to  be  found 
in  the  trial  of  them  by  troops  in  actual  service.  Colonel  Colt's  arms  have  undergone  this 
test,  and  the  result  will  be  found  in  some  measure,  by  reports  of  General  Harney  and  Cap- 
tain Marcy,  who  used  them  in  Florida  against  the  Indians.  These  reports  relate  only  to  the 
rific,  but  are  clear  and  satisfactory.  *  *  *  *  _^  board  of  officers  recently  assembled 
to  consider  the  best  mode  of  arming  our  cavalry,  made  a  report,  showing  the  present 
appreciation  of  the  arm  by  officers  of  the  army  standing  deservedly  high  for  their  services, 
experience,  and  intelligence." 

In  its  internal  construction  this  rifle  differs  in  some  respects  from  the  pistols  and  early 
revolving  rifles.  The  catch  which  causes  the  breech  cylinder  to  revolve,  instead  of  acting 
against  ratchet  teeth,  and  on  the  cylinder  itself,  works  in  teeth  cut  on  the  circumference  ,of 
the  cylinder  end  of  the  base-pin,  in  such  a  manner,  that  the  base-pin  rotates  with  the  cylin- 
der itself,  being  locked  by  a  small  mortise  in  the  cylinder;  and  the  stop-bolt  gears  into  cor- 
responding notches,  also  cut  in  the  end  of  the  base-pin,  and  thus  locks  it  when  required. 
This  is  an  improvement  in  the  arrangement  of  these  weapons,  and  by  a  simple  arrange- 
ment, the  small  spring  catch,  which,  by  means  of  a  circular  groove  in  the  front  end  of  the 
base-pin,  keeps  it  in  place,  is  immediately  released  by  pressing  on  a  small  stud,  and  the 
cylinder  can  be  instantaneously  removed  or  replaced.  Instead  of  the  pin,  which,  in  the 
pistol,  is  used  to  let  the  hammer  down  on,  when  carrying  it,  a  small  recess  is  cut  between 
each  nipple,  in  the  cylinder  itself,  into  which  the  hammer  fits  when  let  do\\ii,  and  makes 
security  doubly  secure. 

The  rifle  is  provided  with  two  sights;  the  ordinary  leaf  sight  usually  employed  is  also 
provided.  The  hinder  sight  is  adjustable  to  suit  long  or  varying  ranges,  and  the  front  sight 
is  that  known  as  the  bead  sight,  which  consists  of  a  small  steel  needle,  with  a  little  head  upon 
it,  like  the  head  of  an  ordinary  pin  inclosed  in  a  steel  tube.  In  aiming  with  this  sight,  the 
eye  is  directed  through  a  minute  hole  in  the  sliding  piece  of  the  hinder  sight,  to  the  small 
bead  in  the  tube,  which  bead  should  cover  the  mark  aimed  at ;  and  this  sight  affords  great 
accuracy  in  shooting.  The  wiping  rod,  which  occupies  the  position  usually  allotted  to  the 
ramrod  in  muzzle  loaders,  is  ingeniously  constructed  so  as  to  admit  of  being  lengthened. 
In  its  interior,  which  is  hollow,  slides  a  slight  steel  rod,  in  end  of  which  a  screw  thread  is 
cut ;  on  drawing  out  the  rod,  a  turn  or  so  of  the  hand  in  one  direction  enables  this  steel  rod 
to  be  drawn  out  to  a  length,  as  nearly  as  possible  that  of  the  outer  case,  and  a  few  turns  in 
the  contrary  direction  fastens  it  firmly  in  its  place;  thus  enabling  it  to  be  used  with  as  much 
facility  as  if  it  were  solid.  When  done  with,  the  reversal  of  the  former  motions  enables  the 
rod  to  be  returned  to  its  original  dimensions,  and  it  can  then  be  returned  to  its  place.  This 
weapon  has  a  real  business-like  serviceable  appearance,  and  its  weight  varies,  according  to 
the  length  of  the  barrel,  from  8  lb.  to  10  lb.  each,  with  five  and  six  shots. 

Colonel  Colt  has  introduced  a  new  shot-gun  which  is  adapted  for  being  loaded  alternately 
with  shot  and  ball.  This  is  adapted  for  the  colonist,  enabling  him  to  use  the  gun  as  an  ordi- 
nary sporting  weapon  for  birds,  &c.,  or  for  more  deadly  purposes.  The  ball  for  Colt's  rifle 
is  shown  by  figx.  594,  595. 

Lancasier'.s  Elliptic  Rife. — So  called,  although  the  elliptical  rifle  is  very  old.  The 
bore  in  this  rifle  is  slightly  oblate  ;  the  twist  found  by  experience,  to  be  most  advantageous 
is  one  turn  in  52  inches,  the  approved  diameter  of  the  bore  "498  inches,  the  length  of  the 
barrel  being  32  inches.  An  eccentricity  of  '01  inch  in  half  an  inch  is  found  sufficient  to 
make  the  bullet  spin  on  its  axis  to  the  extreme  verge  of  its  flight.  The  length  of  the  bullet 
found  to  answer  best  with  these  rifles  is  2^  diameters  in  length,  with  a  windage  of  four  or 
five  thousandths  of  an  inch. 

Major  JVuthaWs  Rifie. — In  the  ordinary  mode  of  grooving  rifles,  sharp  angles  are  left 
between  the  groove  and  "  land,"  (those  parts  of  the  smooth  bore  left  in  their  original  state 
after  the  process  of  grooving  has  been  completed.)  These  create  great  friction  with  the 
projectile,  both  in  loading  and  discharging.  Major  Nuthall  removes  these  objections  by 
rounding  off  the  "  lands  "  into  the  grooves,  that  is,  making  them  a  series  of  convex  and  con- 


956 


EIFLES. 


There  are  also  General  Boileau's  rifle,  and  some  others,  wliich  our  space  will  not  admi( 
of  our  noticing. 

Breicli -loading  Jiijfes  have  been  introduced,  and  they  prove  so  satisfactory  that  the  prin- 
ciple of  breech-loading  is  applied  to  ordinary  fowling  pieces.  Prince's  breech-loader  has  been 
highly  recommended.    In  this  rifle,  Ji(/.  5'JO,  the  barrel  has  attached  to  it  a  lever  with  a  knob 

596 


at  its  end,  kept  in  its  place  and  locked  by  a  little  bolt  attached  to  the  bow  of  the  guard.  In 
order  to  load,  the  stock  being  firmly  grasped  under  the  right  arm,  the  catch  is  released,  and 
the  knob  attached  to  the  lever  is  drawn  to  the  right,  and  almost  simultaneously  pushed  for- 
ward. The  lever  being  firmly  connected  with  the  breech  end  of  the  barrel,  the  whole  of  the 
barrel  is  thus  slipped  forward  in  the  stock,  to  the  extent  of  about  three  inches,  disclosing  a 
steel  cone,  provided  on  either  side  with  inclined  planes,  forming  a  segment  of  a  screw,  and 
locking  tightly  into  slots  at  the  breech  end  of  the  barrel.  The  cartridge  is  dropped  into  the 
open  space  at  the  extremity  of  the  cone,  the  lever  is  depressed,  pull  backward,  and  then 
pushed  into  its  place.  The  barrel  and  cone  are  thus  tightly  locked  together,  and  until  they  are 
in  this  position  the  gun  cannot  possibly  be  fired.  It  is  therefore  obvious,  that  in  strength  and 
security  this  rifle  is  not  inferior  to  any.  At  a  trial  at  Hythe,  Mr.  Prince  fired  120  rounds  in 
less  than  eighteen  minutes,  showing  the  rapidity  of  loading  which  this  weapon  admits  of. 
The  rifling  preferred  by  the  inventor  is  a  five-grooved  bore  rather  deeply  cut,  the  twist  being 
three  quarters  of  a  turn  in  three  feet.  The  London  gunmakers  have  certified  to  the  great 
merits  of  Prince's  breech-loading  rifle. 

Prince's  cartridge  is  an  ingenious  invention  ;  it  can  be  used  either  with  a  muzzle  or  with 
a  breech-loader.  The  cartridge  is  made  of  gun-paper,  produced  in  the  manner  described 
for  making  gun-cotton.  The  spark  fires  this  with  the  powder,  and  if  the  paper  is  pure  there 
is  no  ash  left  from  its  combustion.  5Ir.  Prince  is  bringing  out  a  new  breech-loading  rifle 
which  is  simpler  than  any  yet  produced.  His  practical  experience  in  such  matters,  extend- 
ing over  more  than  a  quarter  of  a  ccntur}',  combined  with  the  success  he  has  already  attained, 
causes  any  fresh  arm  emanating  from  him  to  be  regarded  w-ith  considerable  attention.  The 
breech  is  opened  by  a  half  turn  of  a  lever,  and  closed  by  a  corresponding  movement. 
Either  common  ammunition  or  a  flask  can  be  used  in  loading.  The  barrel  is  a  fixture ;  a 
chamber  being  attached  to  the  breech  end,  so  that  existing  muzzle-loaders  may  be  readily 
converted.  For  cavalry  a  simple  addition  is  made  to  the  arm,  so  that  the  caps  are  placed 
on  the  nipple  in  the  act  of  loading. 

lerri/s  Brcech-loadiny  Rifle  differs  from  Prince's  in  having  the  barrel  fixed.  There  is 
an  opening  at  the  base  of  the  breech,  which  being  lifted  by  a  lever  discloses  a  receptacle 
for  the  cartridge. 

Mr.  Wcxtlcy  Richards,  Mr.  Jamea  Leetch.,  and  some  others  have  introduced  breech-load- 
ing rifles.  Of  the  former.  Colonel  Wilford  says:  "The  weapon  manufactured  by  Mr.  \Vest- 
ley  Richards  is  a  perfect  wonder.  I  saw  a  small  carbine,  weighing  only  5^  lbs.,  fire  better 
at"  800  yards  than  the  long  Enfield." 

In  the  rifle  by  Leetch  the  opening  for  the  admission  of  the  charge  is  in  front  of  the  cham- 
ber ;  consequently  the  shooter  has  all  the  security  that  the  solidity  of  the  breech  can  impart. 

Revolvers  or  Repoaiinci  Pistols. — The  fame  attached  to  Colt's  revolveis,  _/?</.  503, 
renders  them  so  well  known  as  to  require  but  little  introduction.  Although  the  inven- 
tion of  revolvers  of  course  cannot  be  ascribed  to  Colonel  Colt,  their  adaptation  to  modern 
requirements,  and  theirgeneral  use,  are  undoubtedly  due  to  his  extreme  energy,  perseverance, 
and  skill,  and  to  him,  tlicrcfore,  every  credit  ought  to  be  given.  This  make  is  now  exten- 
sively used  in  the  United  States,  and  indeed  in  almost  every  corner  of  the  world,  and  seem 
not  to  lose  favor  anywhere.  In  Turkey,  Eg}'pt,  Brazil,  Peru,  Spain,  Holland,  Prussia,  Russia, 
Italy,  and  Chili,  as  well  as  the  United  States,  and  our  own  country,  they  have  t)een  and  are 
extensively  used  and  approved ;  and  we  are  given  to  understand  that  40,000  of  them  have 
boon  supplied  to  our  authorities,  and  have  been  .served  out  and  used  in  tlie  ]?nltic,  in  the 
Crimea,  in  China,  and  in  India,  with  the  utmost  tfTect.    The  shooting  with  Colt's  arms  is  highly 


KOLLING  MILLS. 


957 


satisfoctory.  With  Colt's  revolver  you  can  make  first-rate  shooting,  and  be  perfectly  satis- 
fied with  its  action.  As  a  proof  that  it  is  not  liable  to  get  out  of  repair,  we  need  only  state 
that  the  American  Board  of  Ordnance  had  a  holster  pistol  fired  1200  times,  and  a  belt  pistol 
1500  times,  without  the  slightest  derangement.  The  penetration  of  the  first  named  was 
through  7  inches  of  board,  and  of  the  second  th:  ough  6  inches. 

The  barrel  is  rifle-bored.  The  lever  ramrod  renders  wadding  or  patch  unnecessary,  and 
secures  the  charge  against  moisture,  or  becoming  loose  by  rough  handling,  or  hard  riding. 
The  hammer,  when  at  full  cock,  forms  the  sight  by  which  to  take  aim,  and  is  readily  raised 
at  full  cock  by  the  thumb,  with  one  hand.  It  has  been  tested  by  long  and  actual  experience, 
that  Colt's  arrangement  is  superior  to  those  weapons  in  which  the  hammer  is  raised  by  pull- 
ing the  trigger,  where  in  addition  to  the  great  danger  from  accidental  discharge,  the 
strength  of  the  pull  necessary  for  cocking,  interferes  with  the  correctness  of  aim,  which  is 
of  so  much  importance.  A  very  effectual  provision  is  made  to  prevent  the  accidental  dis- 
charge of  this  pistol  whilst  being  carried  in  the  holster,  pocket,  or  belt.  Between  each  nip- 
ple (the  position  of  which  secures  the  caps  in  their  places)  is  a  small  pin,  and  the  point  of 
the  hammer  has  a  corresponding  notch ;  so  that  if  the  hammer  be  lowered  on  the  pin,  the 
cylinder  is  prevented  from  revolving,  and  the  hammer  is  not  in  contact  with  the  percussion 
cap,  so  that,  even  if  the  hammer  be  struck  violently  by  accident,  it  cannot  explode  the  cap. 

The  movements  of  the  revolving  chamber  and  hammer  are  ingeniously  arranged  and  com- 
bined. The  breech,  containing  six  cylindrical  cells  for  holding  the  powder  and  ball,  moves 
one  sixth  of  a  revolution  at  a  time  ;  it  can  only  be  fixed  when  the  chamber  and  the  barrel 
are  in  a  direct  line.  The  base  of  the  cylinder  being  cut  externally  into  a  circular  ratchet 
of  six  teeth,  (the  lever  which  moves  the  ratchet  being  attached  to  the  hammer ;)  as  the  ham- 
mer is  raised  in  the  act  of  cocking,  the  cylinder  is  made  to  revolve,  and  to  revolve  in  one 
direction  only  ;  while  the  hammer  is  falling  the  chamber  is  firmly  held  in  position  by  a  lever 
fitted  for  the  purpose;  when  the  hammer  is  raised  the  lever  is  removed,  and  the  chamber 
is  released.  So  long  as  the  hammer  remains  at  half  cock,  the  chamber  is  free  and  can  be 
loaded  at  pleasure.  Revolvers  by  Daw,  by  Adams  and  Dean,  and  others,  have  been  intro- 
duced.    They  are  all  so  similar  in  principle  that  they  need  not  be  described. 

ROLLING  MILLS.  These  useful  aids  to  many  of  our  metallurgical  processes  appear  to 
have  been  introduced  to  this  country  in  the  seventeenth  century;  but  it  was  not  until  1784, 
when  Mr.  Cort  patented  "a  new  mode  and  art  of  shingling,  welding,  and  manufacturing 
iron  and  steel  into  bars,  plates,  &c.,"  that  much  attention  was  directed  to  the  value  of  the 
rolling  mill. 

Fig.  597  is  a  front  view  of  a  pair  of  rollers,  used  in  the  manufacture  of  iron  in  connec- 


tion with  the  puddling  furnace.  They  are  about  4  feet  long,  divided  into  4  parts,  the  largest 
being  about  20  inches  in  diameter.  That  portion  of  the  upper  roller  under  which  the  metal 
is  first  passed,  is  cut  in  a  deep  and  irregular  manner,  resembling  that  chiselling  in  stone 
called  movequc  work,  that  it  may  the  more  easily  get  hold  of  and  compress  the  metal  when 
almost  in  a  fluid  state.  The  plate  is  next  passed  under  the  cross-cut  portion  of  the  roller, 
and  successively  through  the  flat  sections.  The  lower  roller,  it  will  be  observed,  is  formed 
with  raised  collars  at  intervals,  to  keep  the  metal  in  its  ])roper  course.  The  rollers  are  con- 
nected by  cog-wheels  placed  upon  their  axes ;  upon  the  lowermost  of  these,  works  also  the 
wheel  by  means  of  which  the  revolution  is  communicated.  The  cheeks  are  of  cast  iron, 
very  massive,  that  they  may  bear  the  violent  usage  to  which  they  are  subjected. 

We  cannot  go  into  the  numerous  purposes  to  which  rolling  mills  of  this  kind  are  applied; 
a  few  miy  be  mentioned. 

The  practice  of  ".-flitting"  sheets  of  metal  into  light  rods,  cither  for  the  use  of  the  wire- 
drawers  or  of  nail-makers,  is  carried  out  by  means  of  two  large  steel  rollers,  channelled 


958 


ruthenium:. 


circularly,  as  in  Jt^.  598.  These  are  so  placed  that  the  cutters  or  raised  parts  of  one  roller, 
which  are  exactly  turned  for  that  purpose,  shall  work  in  corresponding  channels  of  the  otlui' 
roller,  thus  forming  what  may  be  called  revolving  shears,  for  the  principle  is  that  of  clii)- 
ping;  so  that  a  sheet  of  metal  on  being  passed  through  this  machinery,  is  separated  into  slipis 
agreeing  in  size  with  the  divisions  of  the  rollers. 

Rolling  mills  have  been  patented  for  rolling  tubes  for  gas  and  other  purposes.    See  Tubes. 

599 


For  the  manufacture  of  rails,  rolling  mills  are  also  employed, _/?r/.  599  representing  a  roll- 
ing mill  as  constructed  for  rolling  Birkinshaw's  rails.  The  open  .spaces  along  the  middle  of 
the  figure,  and  which  owe  their  figure  to  the  moulding  on  the  periphery  of  the  rollers,  indi- 
pate  the  form  assumed  by  the  iron  rail  as  it  is  passed  successively  from  the  larger  to  the 
smaller  apertures,  till  it  is  finished  at  the  last. 

IiUTIIENIU.\i.  After  osmium,  ruthenium  is  the  most  refractory  metal  we  are  acquaint- 
ed with.  It  requires  a  very  extreme  heat  to  melt  the  smallest  quantity.  When  melting 
there  is  formed  the  oxide  of  ruthenium  (RuO")  which  is  volatilized,  and  which  smells  some- 
thing like  osmic  acid.  When  removed  from  the  flame  ruthenium  is  blackish  brown  on  the 
surface,  and  is  brittle  and  hard  like  iridium.  It  is  only  distinctly  separated  from  this  last 
metal  Ijy  its  density,  which  is  obviously  half  that  of  iridium.  The  purest  ruthenium  obtain- 
ed weighs  from  11  to  11  '4. 

To  prepare  the  metal  mix  the  osmide  in  fine  powder  with  3  parts  of  binoxide  of  barium 
and  1  part  of  nitrate  of  baryta,  and  heat  them  to  redness  in  a  clay  crucible  for  an  hour. 
The  black  friable  mass  which  remains  is  powdered  with  great  care  and  introduced  into  a 
flask  in  which  has  been  previously  mixed  20  parts  of  water  and  10  parts  of  ordinary  muria- 
tic acid.  The  flask  must  be  placed  in  cold  water  to  avoid  the  elevation  of  temperature 
which  would  ensue  from  the  violent  reaction  which  takes  place.  This  operation  should  be 
conducted  under  a  good  chimney  to  avoid  the  escape  of  the  osmic  acid  vapor  into  the  labor- 
atory. 

Ruthenium  forms  with  zinc  an  alloy  which  will  burn  in  the  air ;  it  crystallizes  in  hexago- 
nal prisms.  With  tin  there  is  formed  an  alloy  RuSn',  which  crystallizes  in  cubes  as  beauti- 
ful in  their  form  and  lustre  as  crystallized  bismuth. — Deville  and  JDebray  on  the  platinum 
tnetals. 

s 


SAFETY  CAGE.  In  all  collieries  the  men  descend  to  their  labor  and  are  raised  from 
the  depth  of  the  mine  by  the  winding  machinery.  This  may  be  described  in  general  terms 
as  a  stage  travelling  in  guides  fixed  to  the  sides  of  the  shafts.  The  rapidity  with  which 
these  stages  are  moved  up  or  down  is  very  great,  and  consequently,  if  any  thing  occurs  to 
engage  the  attention  of  tlie  man  in  charge  of  the  winding-engine,  the  stage  with  its  living 
load  is  either  landed  with  injurious  violence  at  the  bottom  of  the  pit,  or  it  is  carried  over  the 
pulley,  and  thus  the  lives  of  the  men  are  sacrificed.  The  cut  on  the  opposite  page, _/f^.  600, 
shows  an  ingenious  contrivance  for  obviating  the  blow  which  arises  from  reaching  the  bottom 
at  too  great  a  speed,  f,  c  are  platforms  placed  on  India-rubber  springs  (see  Caoutchouc)  h, 
fj,  on  the  landing  at  the  bottom  of  the  pit ;  d  is  one  of  the  cages  which  has  descended,  the 
other  l)eing  supposed  to  be  at  the  surface.  The  elasticity  of  these  springs  certainly  serves 
to  protect  the  men  from  the  violence  of  the  concussion  in  the  event  of  the  rope  breaking,  or  if 
from  any  other  cause  they  suddenly  reach  the  l)Ottom. 

Many  safety  cages,  so  called,  have  l)cen  invented,  the  principles  of  which  arc  to  allow 
them  to  travel  freely  on  their  guides,  so  long  as  the  rope  by  which  they  arc  suspended 
remains  entiie ;  but  in  the  event  of  its  breaking,  the  arms,  levers,  or  catches  seize  the  guide- 
rods,  and  thus  suddenly  stop  the  cage.  Experience  has  not  satisfactorily  confirmed  the 
value  of  these  arrangements. 

A  .simple  arrangement  for  a  safety  cage  was  published  by  Mr.  Andrew  Smith,  in  1852. 
According  to  Mr.  Smith's  invention,  the  drawing  rope  is  connected  with  the  chain-work  suji- 
porting  the  cage  by  a  strong  elastic  tube,  which  gives  the  cage  an  easy  motion  until  an 


SAFETY  LAMP. 
600 


959 


accident  takes  place.  Immediately  the  rope  breaks,  the  weight  of  the  cage  forces  the  end 
of  a  lever  against  the  guide-rods,  which  extend  from  top  to  bottom  of  the  shaft.  The 
following  description  may  render  the  invention  more  intelligible  : — A  horizontal  bar  is 
provided  with  a  slot  at  each  end,  through  which  the  guide-rods  pass ;  at  the  inner  end  of 
each  slot  is  a  pin,  which  forms  the  fulcrum  of  a  lever,  the  shorter  arm  of  which  is  towards 
the  guide-rod. ,  While  the  machinery  is  woi'king  properly,  each  lever  forms  as  it  were  a  link 
of  tiie  chain  by  which  the  cage  is  suspended ;  the  bar  and  the  connecting  levers  forming 
about  an  equilateral  triangle.  To  the  extremity  of  the  longer  arm  of  the  lever  are  connected 
the  rods  by  which  the  cage  itself  is  suspended ;  these  rods  cross  each  other,  and  the  cage  is 
hooked  upon  the  end.  It  will  readily  be  understood  that,  while  all  is  in  order,  the  j^hort  arms 
of  the  lever  are  held  back  from  the  guide-rods,  and  the  slot  of  the  cross-ljar  is  sufficiently 
large  to  admit  the  rise  and  fall  of  the  cage  without  impediment ;  but  upon  the  breakage  of  the 
rope  tlie  long  arms  of  the  levers  are  depressed,  and  the  short  arms  forced,  as  stated,  against 
the  guide-rods,  preventing  the  further  fall  of  the  cage.  The  cost  of  the  contrivance  is  com- 
paratively trifling,  which  is  another  recommendation  to  its  use.  Among  the  more  prominent 
patented  inventions  arc  those  of  Mr.  F.  Emery  of  Cobridge,  Staffordshire,  of  Messrs.  White 
and  Grant  of  Glasgow,  and  of  Mr.  Foudrincr.  Messrs.  White  and  Grant's  cage  is  simple  and 
inexpensive,  no  rack-work  being  retjuired  upon  the  guide-rods,  and  the  suspending  i)ower 
(k'pending  upon  the  simple  turning  of  an  eccentric,  wiiich  is  only  kept  from  revolving  bytlie 
tension  of  the  suspending  rope  or  chain.  An  eccentric  is  placed  on  each  side  of  each  guide- 
rod,  and  while  the  tension  is  sufficient,  the  narrow  parts  of  the  cccenti-ic  being  toward  the 
rods,  there  is  just  room  for  the  guide-rod  to  pass  between  them.  The  l)reakage  of  the  rope, 
however,  relea.scs  the  eccentrics,  and  in  their  attempt  to  revolve  they  grip  the  guide-rods 
and  prevent  the  descent  of  the  cage^ 

Agiin,  a  variety  of  contrivanfces  have  been  introduced  to  release  the  cage  from  the  rope 
or  chain  in  the  event  of  its  being  drawn  up  to  the  pulley:  some  of  these  have  been  adopted 
with  apparent  advantage.  Humane  care,  however,  whatever  may  be  the  mechanical  apiili- 
ances  adopted,  is  necessary  to  insure  safety. 

SAFETY  LAMP.  Numerous  modifications  of  the  Davy  safety  lamp  have  been  from 
time  to  time  introduced.     A  few  of  the  more  important  must  be  named:  — 

1.  George  Stephenson  modified  liis  original  plan.  His  modified  lamj)  consisted  of  a  wire 
gauze  cylinder  about  2J  inches  diameter,  and  aliout  tj  inches  liigii,  with  a  glass  sliield  inside. 
The  air  for  conil)Ustion  was  admitted  througli  a  series  of  perforations  in  the  l)oltom,  and  a 
metal  chimney,  full  of  small  holes,  is  fixed  inside  on  the  top  of  the  glass  cylinder. 


960  SAFETY  LAMP. 

2.  Mr.  Smith,  of  Newcastle,  improved  this  by  covering  all  the  perforations  in  the  metal 
with  wire  gauze. 

3.  Newman,  to  meet  the  objection  that  strong  currents  of  air,  or  of  gas,  could  be  forced 
through  the  gauze,  made  a  lamp  with  a  double  wire  gauze,  commencing  from  nearly  the  top 
of  the  flame  of  the  lamp,  leaving  the  lower  portion  with  one  gauze  only ;  there  was  no  ob- 
struction to  the  light,  and  it  has  not  been  found  possible  to  light  a  gas  flame  by  the  Newman 
double  gauze  lamp,  whereas  this  may  be  done  by  suddenly  driving  the  flame  through  the 
single  gauze  of  the  Davy. 

4.  Upton  and  Roberts,  _^^.  603.  Their  lamp  consists  of  a  wire  gauze  cylinder  5i  inches 
long  and  1|  inch  in  diameter,  which  is  attached  to  the  cylinder  in  the  usual  manner.  The 
lower  half  is  protected  by  a  thick  glass  cylinder,  and  the  remaining  portion  by  one  of  cop- 
per, screwed  to  the  upper  ring  of  the  frame.  The  air  for  combustion  passes  through  a 
range  of  small  openings  in  the  upper  part  of  the  cistern  into  a  space  protected  by  a  double 
shield  of  closely  compressed  wire  gauze.  A  cone  of  sheet  metal  stands  above  this  shield 
and  conducts  the  air  directly  upon  the  wick. 

5.  Martin's  lamp  was,  in  many  respects,  similar  to  Upton  and  Roberts's,  but  so  con- 
structed that  the  flame  was  extinguished  as  soon  as  an  explosive  mixture  was  within  the 
glass  cylinder. 

6.  Dumesnil  sought  to  increase  the  quantity  of  light,  at  the  same  time  that  he  protected 
the  flame  against  any  rapid  current.  The  glass  shield  surrounding  the  flame  is  of  carefully 
annealed  glass,  and  is  protected  from  mechanical  injury  by  curved  metal  bars ;  a  chimney 
of  sheet  metal  being  above  the  glass,  and  all  the  air  being  compelled  to  pass  through 
apertures  rendered  safe  by  the  use  of  wire  gauze. 

7.  Dr.  Clanny,  who  had  for  so  many  years  directed  his  attention  to  safety  lamps,  intro- 
duced a  new  lamp,  with  an  impervious  metal  shield,  having  glass  and  lenses  in  its  sides, 
only  open  at  the  highest  part  of  the  gauze  cylinder  for  about  H  inches.  Thus  there  is  no 
admission  of  air  to  the  lamp,  or  of  the  products  of  combustion  from  the  lamp,  except  over 
the  top  of  the  shield.    This  in  many  respects  resembles  Mueseler's  lamp,  to  be  next  described. 

8.  Mueseler's  lamp  is  shown  in'  section,  fit;.  60-1.  The  cistern  opening  for  the  wick,  &c., 
are  precisely  the  same  as  we  And  in  the  "  Davy."  A  glass  shield  occupies  about  two-fifths 
of  the  entire  height,  the  lower  edge  resting  in  an  annular  recess  on  the  upper  surface  of 
the  cistern.  A  conical  tube  of  metal  carries  off  the  products  of  combustion.  Upon  the 
bars  which  protect  the  glass  rests  the  gauze  cylinder  above  it.  When  this  lamp  is  brought 
into  an  explosive  mixture  the  flame  is  first  lengthened  and  extinguished.  It  unfortunately 
happens  that  by  turning  the  lamp  on  one  side  the  flame  is  often  put  out ;  and  in  the  mines 
of  Liege  boys  are  employed  to  rehght  the  extinguished  lamps.  It  is,  however,  stated  that 
not  less  than  12,000  of  these  lamps  are  in  daily  use  in  Belgium. 

9.  Combe's  and  Boty's  are  modifications  of  the  preceding. 

10.  Parish's  lamp,  one  by  Dr.  Fyfe,  and  some  others  by  Mr.  Eewitson  and  Mr.  Biram, 
involve  the  use  of  talc  in  the  place  of  gas. 

11.  Eloin's  lamp  consists  of  a  cylinder  fixed  upon  the  upper  surface  of  the  cistern  and 
the  glass  shield,  which  is  pierced  with  several  holes  covered  with  wire  gauze,  through  which 
the  air  enters.  As  in  Upton  and  Roberts'  lamp,  a  cone  assists  the  combustion.  A  copper 
chimney  is  connected  with  the  base,  pierced  in  the  upper  end  with  small  holes,  through 
which  the  products  of  combustion  escape.  The  light  is  improved  by  means  of  a  reflector, 
which  slides  upon  the  bai-s,  by  which  the  glass  is  protected. 

12.  Dr.  Glover,  Mr.  Call,  and  Mr.  T.  Y.  Hall  have  recently  introduced  lamps  which  are 
so  similar  to  those  already  named  that  they  need  not  be  described. 

13.  Mackworth's  safety  lamp.  This  safety  lamp  was  contrived  by  one  of  the  Govern- 
ment Inspectors  of  coal  mines,  to  meet  the  objections  raised  in  resisting  the  general  intro- 
duction of  the  Davy  lamp  into  fire-damp  mines.  The  objections  were  the  small  light  given 
by  the  Davy,  which  is  an  inconvenience  in  working  high  seams  of  coal,  or  in  picking  out 
the  shale  and  pyrites  from  the  small  coal  of  dirty  scams.  2dly,  that  the  Davy  was  not  safe 
in  a  rapid  current  of  air  and  gas,  and  that  glass  lamps  were  not  safe  in  places  where  the 
glass  might  become  cracked,  besides  being  heavy  to  carry ;  and,  Sdly,  that  the  ordinary 
locks  of  Davy  lamps  could  be  easily  picked  and  opened  by  the  workmen  to  obtain  more  light, 
and  light  their  pipes.  The  lamp  differs  from  other  glass  lamp^  in  having  a  thick  outer  glass, 
A  A,  fig.  60.5,  and  a  thin  inner  chimney,  b  b.  The  air  enters  to  the  flame,  as  shown  by  the 
arrows,  through  three  wire  gauzes:  1st,  the  cylindrical  gauze,  c;  then  through  the  gauze  d, 
which  supports  the  brass  cover  e,  of  the  glass  chimney  b  ;  and,  Sdly,  through  the  conical 
wire  gauze  f,  which,  with  its  frame,  acts  as  a  support  to  the  glass  chimney  b.  This  conical 
frame  throws  the  air  on  to  the  flame  g,  so  as  produce  a  more  perfect  combustion  and  a 
whiter  light.  A  wire  gauze  may  be  placed  on  the  top  of  the  cover  e,  but  it  is  unnecessary, 
as  the  products  of  combustion  passing  through  the  contracted  aperture,  prevent  any  explo- 
sion passing  up  into  the  cylindrical  gauze  c. 

The  objects  sought  to  be  obtained  in  this  lamp  are,  the  production  of  from  twice  to  three 
times  the  light  of  the  Davy,  by  a  more  perfect  c(ftubustion  of  oil,  throwing  the  light  more 


SAFETY  LAMP. 


961 


603 


605 


up  and  down,  as  shown  by  the  lines  Hi  iio.     The  reflector,  J,  placed  between  the  glasses, 

where  it  is  untarnished  by  smoke,  adds  to  the  light.     This  lamp  burns 

with  a  steady  flame,  in  currents  of  air  which  extinguish  other  lamps.       ^'-'" 

It  is  \^  lb.  heavier  than  a  Davy,  and  li  lb.  lighter  than  a  Mueseler  or 

a  Clanny  lamp.     The  outside  glass  does  not  get  so  hot  as  in  the  two 

latter  lamps,  which  renders  the  glass  liable  to  be  cracked  by  cold 

water ;  and  if  the  outside  glass  is  broken  by  a  blow  or  otherwise,  there 

is  still  a  perfect  safety  lamp  in.side.     The  mode  of  locking  or  riveting 

the  lamp  detects  any  attempt  of  the  workman  to  tamper  with  it.     The 

lead  rivet  k  is  clinched  by  nippers,  leaving  a  die-mark  on  the  lead.  «i^e 

This  lamp  can  be  locked  and  unlocked  in  a  shorter  time  than  other 

locks,  which  is  an  object  when  several  hundred  lamps  have  to  be  given 

out  every  morning  to  workmen. 

Some  other  lamps  have  been  brought  forward,  the  chief  object  be-  S  fe?-^E 

ing  to  prevent  the  lamp  being  opened  by  the  miner,  one  of  the  most 
ingenious  being  the  mincr^s  safety  lamp,  invented  by  Mr.  W.  P. 
Struve,  of  Swansea. 

The  sketch,  ^(/.  606,  will  convey  a  better  notion  of  it  than  any  /    /  ;p^/'| 

written  description,  and  it  is  only  needful  to  add,  that  although  the 
diameter  of  the  gauze  cylinder  at  its  base  is  considerably  more  than  ; 

that  of  the  Davy,  yet  owing  to  the  oil-box  being  placed  within  the  / 

gauze  cylinder,  instead  of  below  it,  and  thus  occupying  a  considerable  i 

portion  of  the  internal  space,  the  cubical  contents  of  the  cylinder  does  ' 

not  exceed  that  of  an  ordinary  Davy.  The  greater  amount  of  cooling  ,  .  ,  :  ;r:;;!ji 
surface  near  the  flame,  atid  the  less  obstructed  admission  of  air  thus  J  /  .  -  '"'jii^ 
obtained,  renders  it  practicable  and  jierfectly  safe  to  use  a  larger  wiii.  '  -"^ 

than  in  the  Davy,  whilst  the  combustion  of  the  oil  is  much  more  \<'  ___^ 

feet,  and  the  smoke  very  considerably  diminislied.     The  light  emittui     b;j_^|  ^^,^^_^Jj     CiSJl 
from  this  lamp  has  been  carefully  ascertained  to  be  equal  to  that       "" '  ^^'|"  ■■"'''''^ii" 
Vol.  III.— 61 


962  SAL  MARINE.       • 

from  three  Davys,  and  owing  to  the  conical  form  of  the  cylinder  and  the  shape  of  the  oil- 
box,  it  diffuses  the  liglit  both  upwards  and  downwards,  as  well  as  in  every  other  diiection, 
with  less  shadow  than  any  other  lamp  that  has  been  offered  to  the  miner.  From  the  more 
perfect  combustion,  the  consumption  of  oil  in  this  lamp  but  slightly  exceeds  that  of  the 
Davy,  whilst  its  simplicity  of  construction  gives  great  facilities  for  keeping  it  in  order  and 
for  repairs.  It  barely  weighs  H  lb.  We  learn  that  this  lamp  has  been  extensively  intro- 
duced into  many  of  the  liery  collieries  in  South  Wales. 

Illuminating  Power  of  Lamps. 

Averaee  number  of 
BXAXOAKC-A  wax  candle,  6  to  the  lb.  ^-J-s  ^^^ 

standard. 

Davy's  lamp,  with  gauze 8-00 

Stephenson's  lamp 18-50 

Upton  and  Roberts's 24'50 

Dr.  Clanny's  (glass) 4-25 

Mueseler's  (glass)  -------         3 "50 

Parish's  lamp,  with  gauze       -         .         .         .  2*75 

Davy's  lamp,  without  gauze   -----         2'50 

Common  miner's  candle,  30  to  the  lb.     -         -         -         2*00 
SAL  MARINE.     Common  salt,  (chloride  of  sodium.) 
SAL  MARTIS.     Protosulphate  of  iron. 
SAL  MIRABILE.     Sulphate  of  soda. 
SALT,  FUSIBLE.     Phosphate  of  ammonia. 
SALT,  GLAUBER'S.     Sulphate  of  soda. 
SALT,  GLAZER'S.     Sulphate  of  potash. 
SALT  OF  LEMERY.     Sulphate  of  potash. 
SALT  OF  TIN.     Protochloride  of  tin. 

SALT,  ROCK,  SEA,  or  CULINARY.     These  terms  are  used  to  designate  different 
forms  of  a  substance  which  is  composed,  chemically  speaking,  of  single  equivalents  of  so- 
dium and  chlorine,  or  of  39"4  parts  of  sodium  and  GO'6  of  chlorine  in  100  parts  by  weight :  it 
is  known  also  by  the  names  of  chloride  of  sodium  and  muriate  of  soda.     {Chloritre  de  sodi- 
lim  ;  Hydrochlorate  de  Sonde,  Fr. ;    Chlor natrium.  Germ.) 

Chloride  of  sodium  generally  occurs  crystallized  in  the  cube,  and  occasionally  in  other 
forms  belonging  to  the  regular  system  ;  amongst  these  varieties,  the  octahedron,  the  cubo-oc- 
tahedron,  the  dodecahedron,  have  been  observed ;  but  there  is  another  which  at  first  sight 
appears  singular,  and  deserves  notice  on  account  of  its  frequent  occurrence.     It  is  called 
the  funnel  or  hopper-shaped  crystal ;  and  is  a  hollow,  rectangular  pyramid,  forming  on  the 
surface  of  a  saline  solution  in  the  course  of  its  evaporation :  it  appears  to  commence  with 
the  formation  of  a  small  floating  cube,  to  the  edges  of  the  upper  face  of  which  lines  of  other 
little  cubes  attach  themselves  by  the  edges  of  their  lower  faces.     By  a  repetition  of  this  pro- 
ceeding, the  sides  of  a  hollow  pyramid  are  formed,  the  apex  of  which,  the  single  cubical 
crystal,  is  downward :  the  crystal  sinks  by  degrees  as  the  aggregation  goes  on  above,  until 
a  pyramidal  boat  of  considerable  size  is  constructed. 

The  crystals  of  chloride  of  sodium  are  anhydrous,  but  generally  contain  a  little  water 
entangled  in  their  interstices,  the  expansion  of  which  causes  them  to  decrepitate  when  heat- 
ed.    This  salt  is  fusible  at  a  red  heat,  and  at  a  white  heat  volatilizes.     Its  crystals  are  white, 
frequently  perfectly  transparent,  of  a  specific  gravity  of  2'13,  and  a  hardness  of  2'6.     A  re- 
markable feature  in  this  salt  is,  that  its  solubility  in  water  increases  but  slightly  as  the  tem- 
perature of  the  latter  is  raised,  for,  according  to  the  experiments  of  M.  Gay-Lussac,  100 
parts  of  water  dissolve 

35-81  parts  of  the  sal,  at  a  temperature  of    SV'O"  Fahr. 
35-88  "  "  62-5°     " 

37-14  "  "  140-0°     " 

40-38  "  "  229-5°     " 

This  must  be  understood  to  apply  only  to  the  pure  substance,  for  the  presence  of  other  salts 
frequently  increases  its  solubility. 

Chloride  of  sodium,  when  perfectly  colorless  and  transparent,  is  also  perfectly  diather- 
manous,  i.e.,  it  allows  the  rays  of  heat  to  pass  through  its  su))stance  almost  without  percepti- 
ble interception.    It  stands  first  among  solid  bodies  in  this  respect,  all  others  absorbing  a  very 
considerable  portion  of  the  heat  which  passes  through  them,  and  some  almost  the  whole : 
Of  100  rays  of  heat  Clear  rock  salt  transmits     -         -         92 
"  Muddv  ditto         ....         65 

"  Plate  glass  -         -         -         -         24 

"  Clear  ice 0 

The  source  of  heat  in  these  experiments  was  red  hot  platinum. 


SALT. 


963 


Chloride  of  sodium  occurs  in  nature  chiefly  in  two  forms,  either  as  rock  salt,  forming 
extensive  deposits,  or  disseminated  in  minute  quantity  through  the  mass  of  the  strata  whicii 
form  the  earth's  crust.  Water  penetrating  the  layers  of  rock  salt,  and  exerting  there  a  solv- 
ent action,  gives  rise  to  the  brine  springs  which  are  found  in  various  countiies ;  whilst 
streams  and  rivers,  dissolving  the  same  substance  out  of  the  strata  through  which  they  flow, 
carry  it  down  to  the  sea,  where,  from  its  great  solubility,  it  has  gone  on  gradually  increasing, 
and  now  constitutes  the  principal  saline  ingredient  in  the  waters  of  the  ocean. 

Even  in  mass,  i.e.,  as  rock-salt,  {Sal  geinme,  F. ;  Stcinsaltz,  Germ.,)  this  substance  pos- 
sesses a  crystalline  structure  derived  from  the  cube,  which  is  its  primitive  form.  It  has 
generally  a  foliated  texture,  and  a  distinct  cleavage,  but  it  has  also  sometimes  a  fibrous 
structure.  Its  lustre  is  vitreous,  and  its  streak  white.  It  is  not  so  brittle  as  nitre ;  its 
hardness  =  2"o,  which  is  nearly  that  of  alum ;  a  little  harder  than  gypsum,  but  softer  than 
calcareous  spar.  Its  specific  gravity  varies  between  2'1  and  2'257.  It  is  white,  occasionally 
colorless,  and  perfectly  transparent,  but  usually  of  a  yellow  or  red,  and  more  rarely  of  a 
blue  or  purple  tinge.     A  few  analyses  will  show  the  general  purity  of  this  substance. 


Wielicika                           Virginia, 
white.       1  ^"=  ''"•  1        U.  S. 

Hall, 
Tyrol. 

Algeria. 

Cheehire. 

Marennes 
red. 

Vie  gray. 

Chloride  of  sodium     - 
"          calcium    - 
"           magnesium 
Sulphate  of  soda 
'•            lime 
"             ma,f,'nesia 
Carbonate  of  magnesia 
Alumina    and     sesqui- 

oxide  of  iron  - 
Clay    -        -        -        - 
Water         ... 

100-00 

99 -SO 

*        * 

•20 

99  55 
trace 

•45 

99-4:3 
•25 
•12 

•20 

* 

99-30 
•50 
•20 

98-30 
-05 
-65 

96-78 

•68 

109 

•60 

-85 

90-3 

2-0 
50 

'  2-o" 
.7 

100  00     1  100-00   1     lOO'OO 

100-00 

100-00 

100-00 

100-00 

10000 

The  principal  impurities  occurring  in  rock  salt  are  sulphate  of  lime,  oxide  of  iron  and 
clay,  but  the  chlorides  of  potassium,  calcium,  and  magnesium,  the  sulphates  of  soda  and  mag- 
nesia, and  bituminous  matters,  are  sometimes  found  in  it ;  and  occasionally  shells,  and  in- 
sect and  infusorial  remains,  exist  enclosed  in  the  mass.  To  the  presence  of  infusoria,  in- 
deed is  attributed  the  red  or  green  color  with  which  some  varieties  are  tinted,  which,  upon 
analysis,  are  found  to  be  absolutely  pure  chloride  of  sodium,  as  in  the  case  of  the  second 
specimen  quoted  in  the  above  table.  Carburetted  hydrogen  gas  iu  a  state  of  strong  com- 
pression is  met  with  in  some  varieties,  and  these  when  dissolved  in  water  emit  a  peculiar 
crackling  sound,  caused  by  the  expansion  and  escape  of  the  confined  gas. 

The  geological  position  of  rock  salt  is  very  variable ;  it  is  found  in  all  sedimentary  form- 
ations, from  the  transition  to  the  tertiary,  and  is  generally  interstratified  with  gypsum,  and 
associated  with  beds  of  cla}'.  When  the  latter  is  present  in  large  quantity,  the  term  "salif- 
erous  clay"  is  applied  to  the  deposit.  The  great  British  deposits  of  this  substance  in  Chesh- 
ire and  Worcestershire  are  found  in  the  new  red  sandstone.  At  Northwich,  in  the  Vale 
of  the  Weaver,  the  rock  salt  consists  of  two  beds,  which  are  not  less  than  100  feet  thick, 
and  are  supposed  to  constitute  large  insulated  masses,  about  a  mile  and  a  half  long,  and 
nearly  1,300  yards  broad.  There  are  other  deposits  of  rock  salt  in  the  same  valley,  but  of 
inferior  importance.  The  uppermost  bed  occurs  at  75  feet  beneath  the  surface,  and  is  cov- 
ered with  many  layers  of  indurated  red,  blue,  and  brown  day,  interstratified  more  or  less 
with  gypsum,  and  interspersed  with  argillaceous  marl.  The  second  bed  of  rock  salt  lies 
?.1|  feet  below  the  first,  being  separated  from  it  by  layers  of  indurated  clay,  with  veins  of 
rock  salt  running  between  them.  The  lowest  bed  of  salt  was  excavated  to  a  depth  of  110 
feet,  several  years  ago.  Many  of  the  German  deposits  of  rock  salt  occur  in  their  buntcr 
sajid.stehi,  which  is  the  representative  of  our  new  red  sandstone,  and  is  so  called  because  its 
colors  vary  from  red  to  salmon  and  chocolate.  In  the  Austrian  Alps  salt  is  found  in  oolitic 
limestone ;  at  Cardona,  in  Spain,  in  the  green  sand ;  and  the  famous  mines  of  Wieliczka, 
in  Galicia,  (excavated  at  a  depth  of  860  feet,  in  a  Layer  500  miles  long,  20  broad,  and 
1,200  feet  deep,)  occur  in  tertiary  strata.  But  in  addition  to  these  concealed  deposits,  this 
substance  presents  itself  in  vast  masses  upon  many  parts  of  the  earth's  surface :  in  the  high 
lands  of  Asia  and  Africa  are  often  extensive  wastes,  the  soil  of  which  is  covered  and  impreg- 
nated with  salt,  which  has  never  been  enclosed  by  superimposed  deposits;  near  Lake  Oroo- 
niiali,  in  the  N.  W.  of  Persia,  it  forms  hills  and  extended  plains;  it  abonnds  in  the  neigh- 
bourhood of  the  Caspian  Sea,  and  penetrates  the  entire  soil  o^  the  steppes  of  the  south  of 
Russia. 

The  Ijcds  of  rock  salt  arc  sometimes  so  thick,  as  at  Wieliczka  and  Northwich,  that  they 
have  not  yet  been  bored  through,  although  mined  for  many  centuries;  but  in  ordinary 
c.'ises  the  thickness  of  the  layers  varies  from  an  inch  or  two  to  ten  or  fifteen  yards.  When 
the  strata  are  thin,  they  arc  usually  numerou.s,  and  throughout  a  certain  extent  i)arallel,  but 


964  SALT. 

when  explored  at  several  points  such  enlargements  and  diminutions  are  observed  as  to  de- 
stroy this  appearance  of  parallelism. 

it  has  been  remarked  that  the  plants  which  generally  grow  on  the  sea-shore,  such  as  the 
Triijlocliinnm  maritimum,  the  Sallconiia,  the  iSalsola  kali,  the  Aster  trifoliian,  or  farewell 
to  summer,  the  Glaux  inarUima,  &c.,  occur  also  in  the  neighborhood  of  salt  mines  and 
salt  springs,  even  of  those  which  are  most  deeply  buried  beneath  the  surface.  It  is  also 
geneially  found  that  the  interior  of  salt  mines  is  extremely  dry,  so  that  the  dust  produced 
in  the  workings  becomes  an  annoyance  to  the  miners,  though  in  other  respects  the  excava- 
tions are  not  insalubrious. 

Much  discussion  has  been  raised  concerning  the  origin  of  these  rock-salt  deposits;  some 
asserting  that  they  were  the  result  of  igneous  agency,  and  others  that  they  have  been  in 
every  case  deposited  from  solution  in  water.  The  great  argument  in  favor  of  the  former  view 
appears  to  rest  upon  the  ftict  that  chloride  of  sodium  and  hydrochloric  acid  gas  are  among 
the  substances  erupted  by  volcanoes ;  whilst  on  the  other  hand  it  is  urged  that  the  speci- 
mens of  erupted  chloride  of  sodium  which  have  been  analyzed  always  differ  much  from  rock 
salt,  since  they  contain  a  large  amount  of  chloride  of  potassium  ;  and  in  addition  to  this,  the 
frequent  occurrence  of  bodies  such  as  bitumen  and  organic  remains,  and  of  cavities  contain- 
ing li(iuids,  and  in  some  cases  gases,  in  almost  all  varieties  of  rock  salt,  are  held  to  furnish 
indisputable  proof  of  the  deposition  of  this  substance  from  its  aqueous  solution.  The  occur- 
rence of  sandstone  pseudomorphs  in  the  cubical  form  of  rock  salt,  also  favors  this  opinion ; 
and  so  also  docs  the  general  character  of  these  deposits ;  they  arc  usually  lenticular,  or  irreg- 
ulaily  shaped  beds,  having  a  great  horizontal  extension,  and  but  rarely  occur  in  the  form 
of  dikes,  or  masses  filling  vertical  fissures,  which  is  the  usual  form  assumed  by  a  molten 
mass  projected  upwards  from  the  interior  of  the  earth.  The  method  of  its  formation  was, 
according  to  those  who  hold  the  aqueous  theory,  somewhat  as  fellows : — A  sea,  such  as  the 
llediterranean,  is,  by  an  elevation  of  the  land  at  Gibraltar,  cut  off' from  communication  with 
the  ocean — the  rate  of  evaporation  from  its  surface  is  greater  than  the  supply  of  water  by 
rain  and  rivers,  consequently  the  amount  of  salt  which  it  holds  dissolved,  increases;  now 
chloride  of  sodium  is  the  principal  saline  constituent  of  sea  water,  and  Bischof's  experiments 
have  shown  that  when  a  solution  of  this  salt  is  allowed  to  be  at  rest,  the  particles  of  salt 
sink,  so  that  the  lower  layers  soon  become  more  saturated  than  the  upper;  concentration 
is  then  supposed  to  go  on  until  at  the  undisturbed  bottom  of  this  inland  sea  a  saturated  so- 
lution of  chloride  of  sodium  exists,  from  which  masses  of  rock  salt  are  slowly  deposited. 
Its  great  purity  is  accounted  for  by  the  fact,  that  tlie  other  salts  existing  in  sea  water  are 
either  far  less  or  far  more  soluble  than  chloride  of  sodium  ;  thus  the  carbonate  and  sulphate 
of  lime  would  be  almost  wholly  precipitated  before  the  solution  became  sufficiently  concen- 
trated to  deposit  rock  salt,  whilst  at  that  degree  of  concentration  the  sulphate  and  chloride 
of  magnesium  would  still  remain  for  the  most  part  in  solution. 

The  principal  European  mines  of  rock  salt  are  those  ol' AVieliczka,  in  Galicia,  excavated 
at  a  depth  of  860  icet  below  the  soil ;  at  Ilall,  in  the  Tyrol,  and  along  the  mountain  range 
tiirough  Aussee,  in  Htyria,  Ebcnsee,  Ischl,  and  Halstadt,  in  Upper  Austria;  Ilallein  in  Salz- 
burg, 3, .300  feet  above  the  sea  level,  and  Rcichcnthal  in  Bavaria;  in  Hungaiy,  at  Marmoros; 
in  Transylvania  and  Wallachia;  at  Vie  and  Dieuze  in  France;  at  Bex,  in  Switzerland;  in 
the  Valley  of  Cardona,  and  elsewhere,  in  Spain ;  and  in  the  region  around  Noithwich,  in 
Cheshire,  in  our  own  country.  Some  of  these  deposits,  as  at  Wieliczka  and  Northwich,  are 
almost  pure  chloride  of  sodium  ;  others,  again,  as  many  of  the  Austrian  beds,  are  only  salif- 
erous  clay;  whilst  others,  as  at  Arbonne  In  Savoy,  elevated  7,200  feet  aljove  the  level  of  the 
sea,  and  in  the  region  of  perpetual  snow,  are  masses  of  saccharoid  gypsum  and  raihydrite, 
which  are  imbued  with  chloride  of  sodium,  and  which  become  quite  light  and  porous  when 
the  salt  has  been  removed  by  water. 

The  natural  transition  from  the  consideration  of  these  strata  of  rock  salt  is  to  those  brine 
springs  which  generally  accompany  them,  and  which  have  frequently  first  called  attention  to 
the  deposits  below.  It  has  been  noticed  that  salt  si)rings  issue,  in  general,  fiom  the  upper 
portion  of  the  saliferous  strata;  cases,  however,  occur  in  which  the  brines  are  not  accom- 
pained  l)y  rock  salt,  and  in  which,  therefore,  their  whole  saline  contents  must  be  derived 
from  the  ordinary  constituents  of  the  strata.  Thus,  in  England,  besides  the  strong  brines 
of  the  new  red  sandstone,  we  have  salt  springs  issuing  from  the  carlioniferous  rocks.  The 
purest  and  most  saturated  brines  are,  however,  found  to  ))e  those  which  can  be  traced  to 
rock  salt  beds,  and  in  the  foremost  rank  of  these  stand  tlie  English  sjirings  of  the  Northwich, 
Middlewich,  and  Sandliach  districts  in  Cheshire;  of  Droitwich  and  Stoke,  in  "Worcestershire; 
and  of  Weston  and  Shii-leywich,  in  Staffordshire;  and  the  continental  hiines  oi  VVilrtcmberg 
and  Prussian  Saxony.     See  first  table,  p.  9()5,  for  the  composition  of  these  saturated  brines. 

(!!omi)arod  with  these  may  be  some  weaker  and  less  ]iure  brines,  which  rise  from  other 
geological  formations.  The  brines  in  the  l^nited  States  come  for  the  most  part  from  Silu- 
rian sandstones,  but  those  in  the  Alleghany  Mountains  sj)ring  from  the  coal;  and  the  weak 
salt  springs  of  Nauheim  and  Ilomburg,  wliich  can  only  be  called  brines  because  chloride  of 
sodium  is  their  largest  constituent,  rise  from  transition  strata.     See  second  table,  p.  905. 


SALT. 


965 


I.     Solid  contents  in  100  parts  of  brine. 

England.                                     1 

1           Wl-rtkmeerg.          1 

Pbctssian 

Cheshire. 

Worceeterehire. 

! 
i 

Marston. 

Wheelock. 

Droitwich. 

Stoke.    1 

Friedrichahall. 

Hall,      i 

Artecu. 

Chloride  of  sodium 

"            potassium  - 
Bromide  of  sodium 
Iodide  of  sodium  - 
Chloride  of  m^nesium 
Sulphate  of  pothssa 
"            soda  - 
"            magnesia  - 
"           lime  - 
Carbonate  of  soda 

"              magnesia 
"             mangauese 
"              lime    '     - 
Phosphate  of  lime 

"             sesqiiioxide 

of  iron  - 

Alumina        ... 

Silica     -        -        -        - 

25-2-i2 

•on 

trace 

trace 
•146 

•391 

•036 

•107 

trace 

trace 

trace 
trace 

25.333 

•020 
trace 

•171 
trace 

•413 

•107 
trace 

•052 
trace 

trace 
trace 

22^452 

trace 
trace 

trace 
•390 

•3S7 
•115 
•034 

trace 
trace 
trace 

25-492   1 

trace 
trace 

traeo 
•594 

•261 
•016 
•034 

trace   ' 

trace 

trace 

I       26563 

•005 

•023 
•4:37 

•010 

25-717 

-     -  : 

•038 
•171    j 

■002 

25-267 
-119 

•421 
-291 

•400 

* 
; 

Solid  contents 

25^9 13 

26-101      1     23-37S 

26-397   ; 

26-033       1  25-92S 

26^49S 

II.     Solid  contents  iii  100  parts  of  brine. 


Amekica. 

Hesse. 

New  York. 
Salina. 

Alleghany 
Mountains. 

Xauheim. 

Homburg. 
Kai-serquelle. 

Chloride  of  sodium  - 
"  potassium 
"  barium  - 
"  calcium  - 
"             magnesium     - 

Bromide  of  potassium 

"             magnesium     - 

Sulphate  of  lime 

Carbonate  of  lime  - 
"                iron     - 

Silicate  of  soda 

Solid  contents     - 

13-239 

-083 
•046 

•569 
•014 
•0U2 

3-200 

•038 
•568 
-293 
trace 

2^7302 

•2655 

•0097 
•01)47 
•1277   - 
•0(115 
•0006 

1 -6(^00 
•0027 

•1300 

•0018 
•1024 
•0096 
•0031 

13  •go  3 

4-099 

3^1399 

1-84'J6 

These  weak  salt  springs  are  supposed  to  have  no  connection  with  beds  of  rock  salt,  but 
to  obtain  their  chloride  of  sodium,  in  common  with  the  other  salts  which  they  contain, 
from  the  strata  which  they  permeate.  The  singular  brines  of  the  Alleghany  Mountains 
must  obviously  pass  through  strata  containing  little  if  any  soluble  sulphate,  otherwise  their 
chloride  of  barium  would  be  separated  as  insoluble  sulphate  of  baryta ;  and  all  indeed  may 
be  regarded  as  coming  more  under  the  head  of  ordinary  mineral  waters,  which  happen  to 
contain  rather  a  large  quantity  of  chloride  of  sodium. 

The  next  source  of  chloride  of  sodium  which  demands  notice  is  found  in  the  inland  seas, 
salt  lakes,  pools,  and  mai-shes,  which  have  their  several  localities  ol)viously  independent  of 
peculiar  geological  formations.  They  appear  to  owe  their  origin  to  two  causes,  being  due, 
firstly,  to  the  formation  of  lakes  upon,  and  the  passage  of  rivers  through,  some  of  the  sur- 
face deposits  of  salt  already  alluded  to;  and,  secondly,  by  the  cutting  off  of  a  portion  of  the 
ocean  by  the  elevation  of  the  land,  and  the  consequent  formation  of  an  inland  lake.  To  the 
former  cause  are  probably  due  the  existence -of  the  Lake  Oroonii;ili  in  tlie  \.  W.  of  Pei-sia, 
the  numerous  brine  pools  of  .Southern  Russia,  and  the  Great  Salt  Lake  of  \.  America.  The 
Lake  Oroomiah  is  82  miles  long  by  24  wide,  and  elevated  4,000  icot  above  the  level  of  the 
sea;  it  is  sinrounded,  especially  on  the  east  and  north,  by  some  of  the  most  remarkable 
surface  despo.-^its  of  rock  salt  in  the  world,  and  through  these  salt  streams  are  continually 
flowing  into  the  lake.  The  Russian  brine  pools  are  situated  in  the  sdt-imprcgnated  steppe 
between  the  rivers  Ural  and  Wolga,  and  doubtless  derive  their  saline  constituents  from 
thence.  The  (ireat  Salt  Lake  is  a  saturated  solution  of  almost  pure  chloride  of  sodium,  but 
whence  the  salt  is  derived  appears  at  present  to  be  but  a  matter  of  conjecture.  To  the  sec- 
ond cause  the  origin  of  the  Dead  Sea  is  frequently  attriljuted ;  its  surface  is  about  1,300  feet 


966 


SALT. 


below  that  of  the  Mediterranean,  and  it  is  thought  to  have  lost  a  column  of  water  of  that 
height  by  evaporation.     The  Crimean  lakes  also  have  probably  originated  thus. 

Bischof  has  shown  that  in  proportion  as  chloride  of  magnesium  increases  in  a  solution, 
it  renders  chloride  of  sodium  and  sulphate  of  lime  more  and  more  insoluble ;  he  is  therefore 
of  opinion  that  at  the  bottom  of  the  Dead  Sea,  and  similar  lakes,  an  impure  rock-salt  deposit, 
interstratified  also  with  mud,  is  forming,  similar  to  the  saliferous  clays  or  clayey  marls 
which  are  frequently  met  with  on  the  continent. 

The  three  following  analyses  exhibit  the  peculiarities  of  two  classes  of  salt  lakes :  Lake 
Oroomiah,  formed  by  the  solution  of  pure  rock  salt,  contains  but  little  magnesia  salt,  whilst 
the  Crimean  Lake  and  the  Dead  Sea,  produced  probably  by  the  evaporation  of  sea  water, 
show  how  the  very  soluble  salts  of  magnesia  increase  as  the  water  concentrates. 

Solid  contents  in  100  parts  of  water. 


Dead  Sea. 

Lake 
Oroomiah. 

Siwasch,  or  Putrid 
Sea,  Crimea. 

Chloride  of  sodium        ... 

"           potassium    ... 

"           calcium        ... 

"          magnesium - 

"  aluminum  .  -  - 
Bromide  of  magnesium ... 
Sulphide  of  calcium  ... 
Sulphate  of  lime    -         .         .         - 

"  magnesia  ... 
Organic  matter      .... 

Solid  contents       ... 

6-578 

1-398 

2-894 

10^543 

•018 

•251 

•088 

trace. 

19^05 
•52 

•18 
•80 

14-20 

•04 
1-93 

trace. 

1-21 
trace. 

21-770 

20-55 

17-38 

Finally,  to  compare  with  the  above  results,  the  composition  of  the  sea  may  be  given  : 
numerous  analyses  have  been  made  of  the  water  taken  at  widely  distant  points,  and  at  dif- 
ferent depths,  and  the  difference  in  composition  has  been  small.  The  water  of  some  par- 
tially enclosed  seas,  as  the  Baltic  and  Black  Seas,  into  Mhich  numerous  rivers  pour,  is  below 
the  average  concentration,  and  that  of  others  again,  as  the  Mediterranean,  is  above  that 
point.  The  deep  sea  water  is  also  more  concentrated  than  that  at  the  surface,  as  Yon  Bibra 
has  shown  that  the  Pacific  Ocean,  in  25°  11'  S.  and  93°  24'  W.  contains  3-47  of  saline  mat- 
ter in  100  parts,  at  a  depth  of  11  feet,  whilst  at  a  depth  of  420  feet  it  contains  3-52.  Bis- 
chof's  experiments,  before  alluded  to,  would  lead  to  this  supposition.  The  following  analy- 
ses are  by  Von  Bibra,  except  the  last,  which  is  by  Laurent : — 


Sol 

id  contents  in  100  parts 

of  sea  water 

English 

Pacific 

Atlantic 

Mediter. 

Channel. 

Ocean. 

Ocean. 

ran  e  an. 

Chloride  of  sodium  - 

. 

2-595 

2-587 

2-789 

2-719 

"           potassium 

- 

•067 

•116 

•154 

•001 

"           magnesium 

. 

•280 

•359 

•233 

•613 

Bromide  of  sodium  - 

. 

. 

•039 

.•052 

. 

Sulphate  of  lime 

. 

-Ill 

•162 

•155 

•015 

"           magnesia 

. 

•225 

•204 

•184 

•701 

Carbonate  of  lime    -         -         .         . 

. 

- 

- 

•001 

"          magnesia 
Solid  contents 

. 

- 

■ 

• 

•019 

3-278 

3-467 

3-507 

4^069 

The  average  specific  gravity  of  sea  water  is  from  1^029,  to  1-030. 

Culinary  salt  is  prepared  from  each  of  the  four  sources  above  mentioned  ;  it  but  rarely 
happens  that  rock  salt  is  sufficiently  pure  for  immediate  use,  and  when  employed,  as  in 
some  places  on  the  continent,  and  formerly  in  Cheshire,  it  is  dissolved  in  water,  the  insolu- 
ble impurities  allowed  to  subside,  and  the  solution  treated  as  a  concentrated  brine.  From 
its  other  sources,  salt  is  ol)tained  by  evaporation,  and  this  is  effected  in  tv,o  ways;  1.  En- 
tirely by  the  application  of  artificial  heat ;  2.  By  natural  evaporation  preceding  the  applica- 
tion of  artificial  heat. 

The  first  method  is  employed  invariably  in  this  country,  and  also  on  the  continent  when 
the  brines  contain  more  than  16  or  20  per  cent,  of  chloride  of  sodium,  the  cost  of  fuel  at 
different  places  of  course  regulating  the  application  of  this  method.  The  manufacture  of 
salt  at  Droitwich  in  "Worcestershire,  is  said  to  have  existed  in  the  time  of  the  Romans,  and 


SANITAEY  ECONOMY. 


U67 


in  Cheshire,  the  "Wiches"  were  very  productive  in  the  reign  of  Edward  the  Confessor; 
some  time  elapsed  before  the  method  of  evaporation  was  devised,  and  the  original  mode  of 
obtaining  the  salt  was  by  pouring  the  brine  upon  the  burning  branches  of  oak  and  hazel, 
from  the  ashes  of  which  the  deposited  salt  was  afterwards  collected.  The  process  of  evap- 
oration was  first  conducted  in  small  leaden  vessels,  which  were  afterwards  exchanged  for 
iron  ones,  having  a  surface  of  about  a  square  yard,  and  a  depth  of  six  inches;  the  size  of 
these  pans  increased  but  slowly,  for  only  a  century  since  the  largest  pans  at  Northwich  were 
but  20  feet  long  by  10  broad.  The  pans  now  in  use  in  Cheshire,  Worcestershire,  and  Staf- 
fordshire have  a  length  of  00  or  70  feet,  with  a  width  of  from  20  to  25,  and  a  depth  of  about 
18  inches;  they  are  made  of  stout  iron  plates  riveted  together,  are  supported  on  brickwork, 
and  have  from  one  to  three  furnaces  placed  at  one  end,  the  flues  of  which  are  in  immediate 
contact  with  the  bottom  of  the  pan.  In  the  works  of  Messrs.  Kay  of  Winsford,  the  brine  is 
heated  to  its  boiling  point  in  a  small  iron  reservoir,  and  from  thence  caused  to  circulate 
through  a  series  of  brick-lined  channels  until  it  is  again,  by  a  simple  arrangement,  pumped 
into  the  first  iron  vessel,  and  heated  afresh.  The  brine  is  generally  raised  by  steam  power, 
and  its  supply  appears  inexhaustible.  The  shafts  are  lined  with  wooden  or  iron  casings  to 
prevent  the  admixture  of  fresh-water  springs  with  the  brine ;  the  depth  of  the  borings  is  in 
Cheshire  usually  from  210  to  250  feet,  but  at  Stoke,  in  Worcestershire,  a  shaft  of  225  feet 
was  constructed,  but  no  satisfactory  supply  of  brine  obtained  until  a  further  boring  of  S48 
feet  was  made.  At  Droitwich  the  borings  are  only  to  a  depth  of  175  feet,  and  so  abundant 
is  the  supply  of  brine,  that  if  the  pumps  cease  working,  it  speedily  rises  to  within  nine  feet 
of  the  surface,  and  if  left  unremoved  soon  overflows.  The  freedom  of  the  brine  from  dilu- 
tion by  fresh-water  springs  is  from  time  to  time  tested  by  the  hydrometer.  From  the  pumps 
the  brine  is  directly  conveyed  by  means  of  pipes  to  reservoirs,  from  which,  as  the  evapora- 
tion proceeds,  it  is  admitted  into  the  pans.  As  the  water  is  vaporized,  the  salt  is  deposited 
and  falls  to  the  bottom  of  the  pan ;  it  is  then  drawn  to  the  sides  by  the  workmen,  until  a 
heap  is  accumulated,  and  from  this  portions  are  ladled  out  into  rectangular  wooden  boxes 
with  perforated  bottoms,  allowed  to  drain  and  solidify,  removed  from  the  boxes,  and  placed 
in  the  drying  room  ;  the  salt  of  coarser  grain  is  simply  drained  roughly  in  baskets  and  dried. 
The  grain  of  the  salt,  i.  e.,  its  occurrence  in  larger  or  smaller  crystals,  is  entirely  the  effect 
of  temperature ;  the  fine  grained  or  table  salt  is  produced  by  rapid  heating,  and  is  formed 
at  that  end  of  the  pan  next  the  fire-place ;  the  coarse  or  bay-salt  is  formed  by  the  slow  evap- 
oration which  goes  on  at  the  other  end ;  whilst  an  intermediate  variety,  common  salt,  is  pro- 
duced in  the  middle.  A  pan  may  sometimes  be  slowly  evaporated  for  the  express  purpose 
of  obtaining  bay-salt. 

In  the  preparation  of  salt  various  substances  have  been  added  to  the  brine  with  a  view 
of  improving  the  quality  of  the  product :  these  have  been  chiefly  bodies  containing  albumin- 
ous matters,  which,  coagulating  upon  the  api)lication  of  heat,  entangle  all  solid  impurities 
and  carry  them  to  the  surface ;  blood,  white  of  egg,  glue,  and  calves'  feet  have  thus  been 
extensively  use.  There  is  also  another  class  of  substances  employed  for  a  different  purpose. 
When  a  concentrated  solution  of  any  saline  matter  is  evaporated,  nmch  annoyance  is  caused 
by  a  layer  of  the  solid  salt  forming  on  the  surface  of  the  liquid  and  impeding  evaporation ; 
this  is  called  a  "  pellicle ;"  to  obviate  this,  and  to  avoid  the  loss  of  labor  entailed  by  constant 
stirring,  oils,  butter,  or  resin  have  been  added  to  the  brine.  The  effect  of  the  latter  is  said 
to  be  perfectly  magical,  the  introduction  of  a  very  few  grains  being  amply  sufficient  to  clear 
the  largest  pan,  and  to  prevent  any  recurrence  of  the  "setting  over." 

SANITARY  ECONOMY.  This  terra  is  used  to  express  and  to  include  every  thing 
which  is  done  or  can  be  done  towards  the  preservation  of  health,  but  in  its  more  restricted 
and  usual  sense  it  is  the  method  of  preserving  the  health  of  communities.  It  therefore 
interests  the  largest  communites,  such  as  nations,  and  the  smallest,  such  as  families,  whilst 
of  necessity  the  interest  of  the  individual  is  not  forgotten ;  and  there  is  a  point  at  which  it 
merges  into  medicine  or  medical  economy.  It  is  sometimes  called  sanitary  science,  but  it 
is  not  well  to  be  very  lavish  of  the  world  science^  which,  although  originally  only  knowledge, 
is  now  better  confined"  to  cases  in  which  nature  herself  has  pointed  out  a  definite  system  of 
laws.  Now  all  the  facts  brought  into  prominence  by  sanitary  economy  are  more  or  less 
connected  with  some  science  the  laws  of  which  are  investigated  in  other  relations ;  but  so 
wonderfully  does  nature  act,  that  isolated  facts  from  all  the  sciences  frequently  come  out 
and  form  a  series  so  connected,  that  for  a  time  the  judgment  is  in  favor  of  believing  tb.at 
they  may  be  so  arranged  as  to  form  a  true  science  ;  and  in  some  cases  this  is  an  open  ques- 
tion. Many  sciences,  perhaps  every  science,  a^ssist  in  the  art  of  true  sanitary  economy.  Its 
necessity  has  arisen  from  that  class  of  misfortunes  to  which  man  has  been  subject  affecting 
his  health  ;  or,  as  some  would  say,  from  certain  defects  of  nature  which  man  is  required  to 
supplement.  Many  of  these  defects  are  told  in  a  long  series  of  the  greatest  miseries ;  some 
in  a  long  series  of  more  limited  but  constant  sorrows  ;  and  others  have  ])een  suHiciently 
small  to  be  considered  rather  as  annoyances.  In  "Bascombe's  History  of  Epidemic  Pesti- 
lences," we  may  read  of  many  hundreds  that  attacked  man  in  every  known  country,  and, 
we  may  almost  add,  in  every  age.     In  the  East  we  have  frequently  mention  of  plagues. 


968  SANITAEY  ECONOMY. 

Pla'i'iies  have  frequently  followed  the  track  of  great,  and  especially  of  defeated  armies, 
as  well  as  taken  refuge  in  beleaguered  cities. 

Ileeker's  "  Epidemics  of  the  Middle  Ages"  shows  few  years  in  which  some  part  of  the 
world  has  not  Vieen  suffering  under  an  epidemic.  In  our  own  times  cholera  has  long  been 
known  to  be  seldom  quite  extinct.  As  an  instance  of  the  mode  in  which  these  epidemics 
travel,  let  us  follow  the  track  of  cholera.  It  first  appeared  at  Jessore,  on  the  Delta  of  the 
Ganges,  reached  Jaulnah  and  Java,  and  the  Burmese  Empire  in  1818;  Bombay,  in  August 
of  the  same  year,  Baracan  and  Malacca;  in  1819,  Penang  in  Sumatra,  8iam,  Ceylon,  Mauri- 
tius, and  Bourbon  ;  in  1820,  in  Tonquin,  Cambogia,  Cochin-China,  South  China,  Philippines; 
in  1821,  Java,  Bantam,  Madura,  Borneo,  &c.,  Muscat  in  Arabia,  and  Persian  shores;  in 
1822-23-24,  Ton(|uin,  Pekin,  Central  and  North  China,  Moluccas,  Amboyna,  Macassar, 
Assam;  in  1822-23,  Persia,  Mesopotamia,  Judjea ;  in  1823,  Astrachan,  part  of  Russia;  in 
1827,  Chinese  Tartary — in  all  these  countries  committing  ravages  hitherto  unheard  of.  In 
1830  it  went  back  to  Russia,  to  Poland,  Moldavia,  and  Austria.  In  1831  it  appeared  in 
Riga  and  Dantzic,  Petersburgh,  Berlin,  Vienna,  Sunderland,  Leith,  and  Calais;  in  1832,  in 
London  ;  1834,  Spain,  the  Mediterranean,  and  North  America.  In  Arabia,  one-third  in  the 
chief  towns  died  ;  in  Persia,  one-si.Kth ;  in  Mesopotamia,  one-fourth  ;  in  a  province  of  Cau- 
casus, 10,000  died  out  of  16,000  ;  in  a  province  of  Russia,  31,000  out  of  r)4,000.  Plagues 
are,  therefore,  still  capable  of  exercising  a  fatal  influence  equal  to  that  of  the  most  ancient 
times.  In  European  towns  generally  the  greatest  number  of  deaths  was  found  to  be  in  the 
districts  least  provided  with  means  of  cleanliness.  It  was  found  among  the  poor  and  ill-fed, 
among  the  dark  races,  and  the  grades  of  lowest  constitutional  power.  {CoplayuVs  Bidioii- 
(,ri/ : — Peslilciicc.)  It  is  also  to  be  remarked,  that  in  all  the  places  where  cholera  was  most 
violent,  civilization  had  not  attained  its  European  maximum.  Cholera  is  an  attack  of  the 
chemical  forces  on  the  vital  forces ;  vital  force  even  in  the  form  of  moral  confidence  repels 
it  to  a  great  extent,  as  it  does  other  infectious  diseases;  but,  for  the  same  reason,  fatigue 
and  depression  of  mind  hasten  the  action.  The  ordinaiy  chemical  forces  act  in  the  viscera 
instead  of  the  chcmico-vital.  The  lungs  are  gorged  with  blood,  unable  to  send  it  aAvay 
oxidized  ;  the  gall  increases  because  carbon  is  not  burnt,  and  urea  is  not  secreted  as  there 
is  no  normal  decomposition  of  the  food.  Vital  force  therefore  fails,  and  a  kind  of  putre- 
faction or  fermenting  action  begins.  This  is  only  one  instance  of  the  many  evils  that  have 
followed  man.  This  is  not  the  place  to  speak  of  black  death,  sweating  sickness,  and  the 
other  diseases,  down  to  milder  influenzas,  which  are  continually  infesting  some  of  our  race. 
Diseases  of  this  kind  are  believed  to  be  caused  by  decomi>osing  matter ;  they  seem  to 
rise  from  foetid  cities  or  foetid  land.  Deltas  have  been  chiefly  blamed  ;  that  of  the  Ganges 
for  cholera,  that  of  the  Nile  for  plague,  that  of  the  Mississippi  for  yellow  fever.  Although 
from  this  view  diseases  would  be  considered  as  under  the  power  of  mankind  to  suppress, 
their  cause  seems  too  widely  diff'used  to  place  them  under  the  direct  control  of  limited 
communities,  much  less  of  individuals. 

About  1350  the  whole  world  was  thrown  into  violent  commotion.  The  change  may  be 
snid  to  have  begun  in  1333,  when  floods,  earthquakes,  and  sinking  mountains  are  spoken 
of  as  occurring  in  China.  Plague  and  parching  drought  covered  much  of  the  East :  Cyrpus 
was  nearly  destroyed.  In  that  island  the  earth  opened  and  sent  out  a  fa>tid  vapor  which 
killed  many.  A  mist,  thick  and  putrid,  came  to  Italy  from  the  East.  Earthquakes  occur- 
red all  along  the  Mediterranean.  Noxious  vapors  and  chasms  seem  to  have  extended 
hundreds  of  miles.  (IJcckrr.)  Diseases  from  these  causes  are  of  course  out  of  our  control. 
Another  natural  source  of  disease  is  the  existence  of  marsh  land,  producing  malaiia. 
Malaria  may  also  be  produced  from  woody  land  and  moist  land,  especially  if  there  be  many 
impurities.  Deltas,  or  low  lands,  at  the  mouths  of  rivers,  land  flooded  either  by  salt  or  I>y 
fresh  water,  especially  if  alternately  by  one  and  the  other,  not  forgetting  the  great  alluvial 
deposits,  which  are  kept  moist  in  hot  climates.  Numerous  as  are  the  cases  of  malaria  where 
it  is  difficult  to  see  the  cause,  the  connection  of  the  marshes  with  some  febrile  diseases  is 
iM'vond  any  question.  The  fevers  from  this  source  seem  in  their  worst  states  to  pass  into 
vfilow  fever.  This  class  of  fevers  is  not  epidemic,  and  does  not  travel  far  from  its  source. 
Tiiere  are  of  course  many  cases  of  its  being  carried  by  the  winds  to  a  great  distance,  and  the 
distance  seems  to  depend  on  the  amount  of  marshy  land,  or,  in  other  words,  on  the  extent 
of  the  poison  produced.     If  little  exist,  it  is  dispersed  before  the  wind  travels  far. 

Conditions  of  the  weather  may  cause  vegetation  to  putrefy  instead  of  growing.  In  IPiOO, 
a  striking  example  of  this  occurred  at  Modena,  although  other  examples  might  be  taken 
much  nearer,  if  there  were  not  such  multitudes  of  opinions  upon  them.  Four  or  five  years 
of  imusual  dryness  had  occurred  ;  fruit  was  abundant,  however,  and  health  satisfactory.  A 
wet  winter  came,  chmdy  and  calm,  without  cold.  This  state  continued  through  summer, 
with  much  rain.  The  numerous  and  noi.sy  grnsshoppeis  of  Italy  almost  ceased,  and  frogs, 
that  belong  to  a  country  of  marshes,  took  their  place.  The  corn  had  ceased  to  grow,  and 
its  place  was  supplied  by  fishes,  so  abundant  was  the  water  on  the  land ;  whilst  also  organic 
matter  was  driven  into  the  steams  in  unusual  quantities.  Vegetation  was  attacked  with 
rubiffo — a  rusty  withered  appearance — which  increased  in  spite  of  all  precaution ;  begin- 


SANITARY  ECONOMY.  9G9 

ning  with  the  mulberry,  it  attacked  the  corn,  and  then  the  legumens,  and  especially  the 
beans.  This  extended'  over  the  higher  spots  as  well  as  the  lower.  It  was  melancholy  to 
look  on  the  fields,  which,  instead  of  being  green  and  healtliy,  were  everywhere  black  and 
sootv.     "The  very  animals  returned  the  food  which  they  had  eaten.    .  .  .    The  sheep  and 

the  silkworms  perished The  bees  made  their  honey  with  timidity The  waters 

became  corrupt,  and  fevers  attacked  the  inhabitants,  chiefly  tlie  country  people,  such  as 
Hved  on  the  wet  lands.     This  state  produced  intermittent  fevers." — Bern.  Ramazzini. 

Asain,  there  are  causes  purely  artificial  arising  from  the  state  of  our  towns  in  maim- 
facturing  districts. 

It  has  been  proved  that  diseases  may  be  produced  artificially  of  a  kind  closely  resembling 
the  great  world  epidemics.  When  persons  live  closely  crowded  together  health  gradually 
begins  to  fail,  and  loathsome  diseases  rapidly  grow.  These  diseases  very  immeasurably, 
a:\d  the  variation  seems  to  be  as  a  great  as  the  modes  of  decomposition  of  animal  matter. 
Ai'ter  a  time  these  diseases  attain  virulence  sufiicient  to  be  infectious  or  contagious  through 
the  atmosphere. 

These  various  conditions  are  not  perfectly  understood,  but  even  the  statement  of  our  as- 
certained knowledge  has  been  most  widely  misunderstood  by  the  pubhc,  and  sometimes 
even  by  professional  men,  many  of  whom,  if  they  have  conceived  the  matter  clearly,  have 
not  expressed  it  well. 

There  are  at  least  three  principal  methods  by  which  the  air  is  rendered  impure.  1st. 
by  noxious  gases,  dust,  and  ashes,  produced  by  geological,  atmospheric,  or  artificial  causes, 
sulphurous  gas,  carbonic  acid,  sulphuretted  hydrogen,  and  perhaps  many  others.  2.  Epi- 
demic or  travelling  causes  to  all  appearance  reproducing  themselves  as  they  advance,  as  in 
plague  and  cholera.  Similar  diseases  produced  by  artificial  or  neglected  accumulations  of 
filth.  3.  Malaria,  or  diseases  caused  by  the  disturbed  or  badly-regulated  relation  between 
tlie  soil  and  the  atmospheric  conditions,  whether  from  natural  or  artificial  causes.  It  would 
bo  difficult  to  include  all  the  various  evils  arising  from  too  much  heat,  cold,  &c.,  &c. ;  know- 
ing these  things,  we  are  able  to  a  considerable  extent  to  guide  ourselves.  When  the  disease 
or  nuisance  is  caused  by  processes  of  manufacture  the  law  sanctions  interference.  The 
judicious  management  of  this  branch  of  the  subject  is  of  the  greatest  importance  to  the 
community. 

There  are  also  causes  of  disease  relating  more  to  the  condition  of  the  atmosphere  ;  for 
example,  from  the  prolongation  of  a  current  of  air  or  wind  from  one  particular  district, 
without  due  mixture  ;  and  from  conditions  of  moisture,  and  of  electricity. 

Sanitary  economy  devises  a  method  of  avoiding  the  diseases  spoken  of.  As  to  the  first, 
those  produced  by  geological  phenomena,  our  chief  protection  lies  in  the  choice  of  place : 
this  remark  may  also  apply  to  those  diseases  produced  by  atmospheric  stagnation  and 
electrical  condition.  AH  we  can  do  is  to  choose  places  which  are  known  to  be  free  from 
disturbances  or  irregularities ;  when  such  occur,  we  are  then  able  only  to  remove  or  to 
suffer.  Such  diseases  are  but  Tittle  understood.  When  the  disease  is  epidemic,  some  trace 
its  origin  to  causes  which  may  be  termed  cosmic.  One  may  be  an  excess  of  the  decompos- 
ing agent,  or  by  conditions  of  the  atmosphere  unfavorable  to  the  continuation  or  tenacity 
of  delicate  chemical  compounds.  Take,  as  illustration,  milk  during  a  thunderstorm :  this 
action  is  probably  caused  by  a  very  rapid  oxidation,  which  oxidation  begins  the  phenomena 
of  putrefaction.  To  bring  such  an  analogy  to  explain  the  condition  generally  of  organic 
matter,  is  legitimate,  and  we  may  either  suppose  the  action  to  begin  in  living  animals  them- 
selves, or  on  substances  external  to  them.  The  belief  may  be  said  to  be  established  by  a 
long  host  of  great  observers,  that  putrefying  matter  produces  diseases  under  certain  not  very 
well  known  conditions,  and  that  it  reacts  unfavorably  on  the  health  in  every  condition,  and 
as  a  cause  of  instant  death  in  concentrated  forms.  In  Cairo,  where  houses  are  crowded 
with  the  living,  and  where  the  dead  are  buried  with  slight  covering,  underneath  the  living, 
there  seems  to  be  a  periodic  clearing  out  of  the  population  by  plague,  reducing  the  number 
until  there  be  enough  of  air  to  allow  of  healthy  life.  In  our  own  prisons  at  one  time  tlie 
same  tiling  occurred,  and  in  many  of  the  prisons  of  the  world  impri.sonment  is  deatli ;  such 
as  in  Turkey,  China,  and  ])laces  not  civilized  by  modern  sanitary  knowledge.  Prisons  in 
Iv.irope,  also  might  readily  be  mentioned  as  most  unwholesome  ;  and  prisons  and  work- 
hi)uses  in  England  itself,  where  tlie  greatest  care  must  be  taken  to  prevent  want  of  clean- 
liness, as  it  produces  an  immediate  result  in  disease.  This  is  merely  on  a  small  scale  what 
takes  place  on  a  great  scale  in  nature.  It  is  similar  to  what  we  every  day  .«ee,  that  man  lays 
hold  of  some  of  the  facts  of  nature,  and  under  his  hand  they  act  by  the  same  laws  a.s  they 
do  in  their  cosmic  manifestations.  So  in  his  disexses,  man  produces  them  by  causing 
circumstances  so  to  concur  that  the  laws  of  nature  act  under  his  hand  as  they  do  when  he 
has  not  interfered.  Sanitary  inquirers  have  ultimately  been  compelled  to  attribute  many 
of  the  greatest  effects  on  health  to  decomposition  of  organic  matter.  Almost  all  ages  have 
referred  to  putrefaction  or  fermentation  as  an  evil.  The  words  have  been  used  synony- 
mou.sly.  For  various  opinions  on  this  subject  see  Disinfectant.  M.  Place,  in  17-1,  says 
that  in  ^^'dr-' ''action  a  body  works  another  lo  conformity  with  itself.     This  is  believed  to  be 


970  SANITAEY  ECONOMY. 

the  case  in  many  diseases.  One  erroneous  opinion  is  very  common.  Gases  which  might 
be  prepared  in  the  chemist's  laboratory  liave  been  blamed  as  the  causes  of  infectious 
diseases.  Sulphuretted  hydrogen  and  carbonic  acid  are  spoken  of  as  if  they  were  infectious, 
and  productive  of  fevers.  Permanent  cliemical  compounds,  gaseous  or  otherwise,  are  not 
capable  of  acting  as  infections.  The  idea  of  infection  given  is  that  of  a  body  in  a  state  of 
activity.  But  any  gas,  the  atmospheric  mixture  excepted,  is  capable  sooner  or  later  of 
causing  death.  A  true  gas  diffuses  itself  in  the  air,  and  is  rapidly  removed  from  any  spot ; 
tu  render  a  i)lace  long  unwliolesome  the  gas  must  be  continuously  generated  at  the  spot. 
The  movements  of  plagues  are  not  similar  to  anything  we  know  of  gases ;  on  the  contrary, 
we  know  that  gases  could  not  move  in  the  manner  that  cholera  and  plague  do.  .Sulphuret- 
ted hydrogen  is  not  miasma,  it  is  poisonous ;  it  may  destroy  the  constitution  and  produce 
diseases  which  may  be  deadly  enough^  but  the  sources  of  it  are  resorted  to  by  invalids ;  this 
would  never  be  the  case  were  it  a  miasm.  It  has  occasionally  an  internal  beneficial  action, 
and  although  in  using  it  a  little  be  taken  into  the  lungs,  this  momentary  breathing  is  not 
found  prejudicial ;  but  an  amount  of  cholera  infection,  such  as  we  could  perceive  by  the 
nose  as  readily  as  sulphuretted  hydrogen,  would  no  doubt  be  a  most  deadly  dose ;  we 
probably  know  of  no  such  amount.  The  same  may  be  said  of  carbonic  acid  and  other  gases. 
Some  persons  are  capable  of  smelling  the  miasms  of  certain  places — no  doubt  very  fine 
senses  could  detect  them  wherever  they  existed ;  but  generally  bad  air  may  injure  very  im- 
portant organs  without  any  effect  being  perceived  by  the  senses  until  the  evil  has  become 
very  great.  The  chemical  action  is  not  one  that  the  senses  fully  observe.  Fermentation 
and  putrefaction  exhaust  their  powers  after  a  short  time,  and  cea,se  ;  so  do  infections,  but 
not  so  pure  gases,  which  act  only  by  combining.  The  fermenting  substances  lose  their 
power  not  by  combination  so  much  as  a  change  of  condition,  a  transformation  of  their  parti- 
cles. All  these  actions,  similar  to  fermentation,  are  connected  with  moist  bodies :  dried 
bodies  cannot  ferment,  putrefy,  or  infect.  (See  Pi'trefactiox,  vol.  ii.)  Infection,  like 
fermentation,  is  most  violent  at  an  early  stage,  gradually  spending  its  strength,  and  frequent- 
ly changing  a  portion  of  the  substance  into  analogous  forms.  It  has  been  argued  that 
putrefraction  cannot  produce  disease ;  but  there  are  no  facts  in  nature  better  established 
than  the  production  of  disease  by  the  presence  of  dead  animals  or  vegetables,  especially  the 
first.  The  production  of  fever  by  crowding  hospitals,  barracks,  and  ships,  is  as  easy  as  the 
formation  of  many  other  artificial  organic  actions,  although  no  exact  form  of  fever  can  be 
produced  at  will ;  cases  depending  no  doubt  on  time,  place,  climate,  and  constitution.  The 
knowledge  of  these  facts  concerning  zymotic  diseases  leads  to  this  conclusion  :  in  order  to 
avoid  the  evil  effects  of  decaying  matter,  it  is  necessary  to  have  all  our  surroundings  as 
clean  as  possible.  Sanitary  economy  resolves  itself  at  last  chiefly  into  cleanliness.  In- 
dividuals may  learn  pei-sonal  cleanliness,  but  to  render  a  town  or  a  county  clean  many 
difficult  arrangements  are  needed.  Impurities  arise  from  the  conditions  of  animal  life. 
Life  is  generated  by  the  activities  of  certain  substances  which  compose  animals.  "When  the 
activity  is  over  the  substances  are  dead  and  unpleasant,  and  they  pass  into  their  former 
condition  through  a  number  of  stages.  In  some  of  these  stages  the  substances  are  gaseous, 
some  liquid,  some  solid ;  we  may  add,  some  in  the  state  of  vapor.  Some  of  these  sub- 
stances are  exhalations,  some  excretions.  Exhalations  come  from  the  surface  of  the  whole 
body,  but  from  the  lungs  principally.  The  lungs  give  out  air  with  about  4,  6,  and  even  8 
per  cent,  of  carbonic  acid  in  it,  and  the  amount  respired  is  about  380  cubic  feet  in  24  hours, 
and  about  31  cubic  inches  per  respiration,  and  15  respirations  per  minute.  The  amount  of 
air  proposed  as  the  supply  for  an  individual  varies  greatly.  Dr.  Reid  gave  30  cubic  feet 
per  minute  —  1,800  feet  per  hour,  and  even  3,600.  Liebig  supposes  216  feet  per  hour.  Dr. 
Keid  gave  more  than  was  considered  agreeable.  Brennan  supposes  about  600,  and  calculates 
the  following  for  every  room  per  minute  and  per  individual,  the  air  being  at  64°,  and  dew 
point  at  50" : 

For  supply  to  the  lungs 0-83  feet 

To  carry  off  insensible  perspiration        ...         -    10-2     " 

For  each  common-sized  candle 0'25  " 

If  heated  air  is  used  for  warming — 

For  each  square  foot  of  glass  in  the  window  -         -         -      I'D     " 
Each  window  to  make  up  for  leakage    ....      8"5     " 

Each  door  for  the  same 5  2" 

Eaclx  200  square  feet  of  wall  and  ceiling        -         -         -      1        " 

Allowing  this  to  be  excessive,  the  advantage  of  pure  air  is  still  to  be  urged,  and  it  is 
desired  most  by  the  healthiest  specimens  of  men. 

In  speaking  of  the  impure  gases  of  the  air,  carbonic  acid  is  generally  referred  to. 

This  carbonic  acid  has  been  considered  to  be  the  great  cause  of  disease  in  crowded  local- 
ities, but  the  conclusion  is  contrary  to  our  knowledge  of  the  effects  of  carbonic  acid  when 
pure.  There  can  be  little  doubt  that  there  is  a  considerable  amount  of  organic  matter  in 
the  air  of  crowded  places,  and  to  that  organic  matter  must  be  attributed  most  of  the 


SANITARY  ECONOMY.  971 

evil.  It  may  be  true  that  1  per  cent,  of  carbonic  acid  may  be  observed  by  the  senses,  but 
this  is  generally  tried  with  carbonic  acid  given  out  from  the  lungs.  In  the  case  of  a  prison 
in  Germany,  2  per  cent,  of  carbonic  acid  was  found  in  the  air.  Skin  diseases  appeared 
rapidly,  and  deaths  were  excessive.  But  we  do  not  know  the  action  of  the  pure  gas ;  there 
must  have  been  a  large  amount  of  corrupt  matter  in  air  which  contained  2  per  cent,  of 
carbonic  acid  escaped  from  persons.  It  shows  also  great  general  filth.  Amounts  of  organic 
matter,  which  are  wonderfully  less  than  even  a  hundredth  of  a  per  cent.,  are  known  to 
make  the  air  unhealthy.  In  Manchester  it  seems  to  be  the  sulphurous  acid  which  is  chiefly 
felt,  and  that  when  it  is  less  than  one  in  a  million,  although  it  rises  up  in  some  places  close 
to  chimneys  to  1,  and  even  4,  in  100,000. 

It  is  not  intended  here  to  give  statistics  of  disease,  but  it  will  be  right  to  refer  to  the 
enormous  amount  of  disease  amongst  miners  in  Cornwall.  The  depths  being  great,  above 
1,800  feet  in  some,  and  the  temperature  rising  to  about  100",  the  difficulty  of  working  is 
extremely  great.  Candles  are  burnt,  and  the  air  has  become  so  deteriorated  that  it  contain- 
ed less  than  18  per  cent,  of  oxygen.  The  amount  of  carbonic  acid  had  not  risen  above 
O'OSo  per  cent.,  which  is  not  very  high.  Mr.  R.  Q.  Couch,  Sir  J.  Forbes,  and  Mr.  Mack- 
worth,  have  successively  reported  on  this  subject  and  given  some  interesting  details.  Mr. 
Roberton,  of  Manchester,  remarks  on  the  great  cleanliness  of  the  women  ;  but  they  do  not 
enter  the  mines,  and  their  lives  are  longer.  Consumption  destroys  the  men  rapidly  in  many 
of  the  deep  mines.* 

Exhalations  from  the  skin  are  abundant,  both  acid  and  oleaginous. 

Dr.  Vogel  found  organic  matter  in  the  air  of  his  class-rooms  after  a  lecture.  Dr.  Angus 
Smith  has  shown  that  the  exhalations  may  be  traced  on  the  walls  of  crowded  rooms,  which 
become  coated  with  organic  matter  ;  and  he  adds  that  the  furniture  becomes  coated  with  a 
similar  substance,  which  must  be  continually  removed.  Thus  furniture  and  walls  which  are 
never  touched  in  time  become  impure,  and  give  out  noxious  exhalations  when  these  sub- 
stances begin  to  decompose.  Again,  these  substances  are  caught  in  our  clothes  and  are 
retained  there  in  a  decided  manner,  on  account  of  a  peculiar  faculty  of  retention  in  the 
fibre.  This  necessitates  constant  washing.  Long  custom  has  shown,  that  when  retained  by 
the  cloth,  a  certain  amount  of  it  becomes  innocent ;  that  is,  different  fibres  have  the  power 
of  retaining  matter  so  firmly  that  it  is  imperceptible  and  incapable  of  acting  on  the  air. 
Wool  has  this  fiiculty  to  a  great  extent ;  linen  and  cotton  to  a  less  extent.  For  this  reason 
wool  can  be  worn  longer  next  the  skin,  remaining  in  reality  clean.  Clothes  that  are  to  be 
kept  in  good  condition,  if  made  of  wool,  as  men's  coats,  cannot  be  washed:  for  this  reason 
the  custom  has  gradually  been  formed  of  wearing  under  clothing,  which  absorbs  condcnsible 
substances  especially,  and  is  then  washed,  keeping  the  exterior  clothing  for  a  long  time 
clean.  As  porous  substances  have  an  oxidizing  power,  it  is  probable,  that  if  not  too  much 
organic  matter  is  supplied,  the  exterior  clothing,  well  aired,  may  be  kept  absoliltely  clean, 
not  merely  by  our  ordinary  practice  of  brushing  and  dusting,  but  also  by  oxidation,  in  the 
same  way  as  Dr.  Stenhouse  has  shown  oxidation  to  take  place  in  pores  of  charcoal.  The 
instant  removal  of  the  breath  and  other  exhalations  is  of  great  importance.  This  properly 
comes  under  the  head  of  warming  and  ventilating.  Walter  Brennan,  C!.E.,  in  his  "  Ili.story 
of  Warming  and  Ventilating,"  gives  a  remarkable  amount  of  information.  There  have 
been  many  mistakes  as  to  the  effect  of  overcrowding ;  its  evils  have  actually  been  denied. 
The  facts  are  very  decided.  Isolated  houses  may  be  crowded  so  much  as  to  produce  dis- 
eases, or  they  may  be  so  badly  ventilated  without  crowding  as  to  have  the  same  result.  In 
this  way  persons  in  the  country  may  have  all  the  disadvantages  of  a  crowded  town.  Again, 
a  town-house  well  ventilated  may  have  many  of  the  advantages  of  the  country,  because, 
ulrhough  the  air  is  not  of  the  purest,  it  may  never  be  allowed  to  sink  below  the  average 
purity  of  the  external  air.  Indeed,  freedom  from  disease  is  obtained  in  towns  better  in  all 
eases  than  where  there  is  a  malarious  atmosphere  outside  the  town  :  this,  of  course,  is  well 
known  ;  and  at  the  same  time  diseases  from  putrefaction,  caused  by  want  of  space  and  clean- 
liness, are  cured  by  leaving  a  town.  Persons  slightly  exposed  to  the  odor  of  water-closets 
in  towns  are  frequently  subjected  to  disease,  the  unoxidized  air  poisoning  them,  whilst 
persons  working  in  the  open  air  escape,  although  laboring  amongst  the  excreta  themselves. 
Again,  persons  living  in  the  house  are  exposed  to  the  excreta  a  day  or  two  old,  wliilst  in 
the  case  of  nightmen,  it  has  frequently  passed  its  worst  stage  when  tliey  apjiroach  it.  The 
stage  giving  off  sulphuretted  hydrogen  is  by  no  means  the  worst,  peihaps  one  of  the  most 
innocent  of  the  unpleasant  stages,  unless  this  gas  be  very  strong,  when  it  is  fatal.  But 
even  in  the  minutest  quantity  this  gas  is  hurtful  to  persons  contiiniously  exposed. 

The  mode  of  removing  excreta  is  an  important  point.  Most  inipiirers  have  decided 
against  leaving  them  in  a  town,  and  against  allowing  them  near  a  house.  These  conclusions 
are  especially  valuable  for  town  hou.ses.  We  have  in  some  towns  whole  streets  of  middens 
behind  the  hou.ses,  and  the  air  behind  is  always  inferior  to  the  front  air.  The  process  of 
carting  refuse  is  also  a  great  evil  in  a  town.     No  plan  removes  filth  so  rapidly  as  that  with 

*  "J/tn«r's  consumption,^''  as  tljo  disease  wliicli  destroys  tlio  miner  is  naincil,  prevails  also  in  the  lead 
mines  of  the  northern  counties,  which  are  usually  shallow. — {Hd.) 


972  SANITAPwY  ECONOMY. 

water.  Many  people  object  to  it,  because  vre  have  not  yet  learnt  to  make  good  sewers. 
Sewers  should  be  tight.  The  Board  of  Health  introduced  small  and  rapid  streams  in  the 
sewers,  objecting  to  the  canal-like  sewers,  which  are  as  bad  as  cesspools,  on  account  of  the 
enormous  amount  of  deposit  in  them,  and  are  reservoirs  of  foul  air  from  the  amount  of 
putrefaction  going  on  within  them.  Many  persons,  not  seeing  this  evil,  have  desired  again 
to  return  to  the  no-plan  of  middens,  not  seeing  what  a  deplorable  result  has  been  attained 
in  Paris,  where  although  using  air-tight  vessels  to  remove  the  refuse,  they  render  most  of 
the  houses  redolent  of  night-soil.  The  towns  treated  on  the  rapid  removal  eystem  are 
models  of  cleanliness,  and  we  do  not  doubt  the  speedy  increase  of  the  plan,  especially  as 
carried  out  by  Robert  Ilawlinson,  C.E.  It  must  be  confessed,  however,  that  the  great 
objection  to  the  plan  is  one  which  is  not  to  be  depised.  There  is  too  much  water  used ;  if 
the  water  flows  into  the  streams  they  are  spoiled,  and  it  is  scarcely  possible  to  put  it  on 
land.  This  difficulty  must  be  met,  or  the  plan  so  admirable  for  towns  will  be  found  de- 
structive to  countries.  There  is  one  way  of  meeting  it,  that  is,  by  making  the  liquid  denser, 
and  so  having  it  so  strong  as  to  be  a  valuable  manure.  By  a  double  system  of  drainage 
this  might  be  eftected,  the  rain  water  going  in  a  separate  sewer.  F.  0.  Glassford  proposes 
a  water-closet  which  shall  hold  the  excreta  till  they  are  mixed  up  to  a  thickish  liquid  with 
water ;  he  then  removes  it  by  pipes  to  certain  reservoirs,  and  makes  solid  manure  from  it 
by  sulphuric  acid  and  evaporation,  a  plan  which  he  has  found  to  answer.  Dr.  Joule  pro- 
poses large  iron  tanks  for  each  block  of  houses,  to  be  emptied  daily,  and  disinfected  on 
being  emptied.  All  such  plans  must  be  inferior  to  the  cleanliness  caused  by  abundant 
water.  We  must  learn  to  remove  our  filth  from  our  towns,  or  they  will  be  as  unwhole- 
some as  they  once  were.  Nothing  but  abundant  water  can  make  the  largest  city  in  the 
world  (London)  the  healthiest  oPlarge  cities. 

The  assertion  of  the  Board  of  Health  is  that  combined  works,  comprising  a  water-pipe 
for  the  service  of  each  house,  a  sink,  a  drain,  and  a  waste-pipe,  and  a  soil  pan  or  water- 
closet  apparatus,  may  be  laid  down  and  maintained  in  action  at  a  cost  not  exceeding  on  the 
average  three  half-pence  per  week,  or  less  than  half  the  average  expense  of  cleansing  the 
cesspool  for  any  single  tenement.  This  seems  borne  out  by  the  example  of  several  towns 
under  the  care  of  engineers  penetrated  with  the  spirit  which  dictated  the  changes.  To  the 
above  amount  has  been  added  water  supply,  which  has  increased  the  sum  to  threepence  per 
week. 

Sewers  must  certainly  not  leak,  or  they  must  be  disinfected.  Dr.  Angus  Smith  proposed 
long  ago  that  they  should  be  disinfected  nearly  from  their  sources.  In  other  words,  dis- 
infectants should  flow  through  all  the  great  sewers,  and  so  bring  them  to  the  rivers  in  a 
state  where  putrefaction  is  impossible.  The  advantage  of  this  would  be  great.  When  Mr. 
McDougall  was  showing  his  plan  of  disinfecting  sewers  to  the  Board  of  Works,  the  smell 
of  the  substance  he  used  when  he  tried  it  in  excess  was  perceived  in  the  houses  along  the 
line  of  the  sewer,  showing  clearly  that  the  present  sewers  allow  their  filthy  smells  to  go  into 
the  air  of  houses.  lie  completely  destroyed  the  sewer  smell.  To  prevent  bad  air  in  sewers, 
some  persons,  and  amongst  others  some  in  the  Board  of  Health,  have  proposed  ventilation, 
and  have  thus  polluted  towns  with  the  air  which,  after  all,  may  be  better  where  it  was.  To 
obviate  this,  they  sometimes  filter  the  air  through  cliareoal  Ijcfore  allowing  it  to  escape. 
No  plan  will  succeed  but  that  which,  by  preventing  putrefaction,  prevents  entirely  the 
formation  of  foul  air.  At  present  all  the  lines  of  sewers  are  unclean ;  they  may  all  be 
cleaned  by  antiputrcscent  Substances.  If  every  family  used  them,  even  the  smallest  drains 
would  be  disinfected  with  univeral  benefit.  Of  course  the  Thames  would  cease  to  putrefy 
if  the  larger  sewers  were  all  treated  in  this  way. 

When  the  excretions  are  allowed  to  accumulate  in  a  town  behind  the  houses,  as  in  Leeds 
and  manv  other  large  manufacturing  towns,  they  must  of  course  be  periodically  removed, 
as  the  amount  of  impure  vapor  is  very  much  in  proportion  to  the  surface  exposed.  There 
is  little  improvement  caused  by  slightly  diminishing  the  solid  contents.  When  removed,  it 
must  be  taken  either  to  deposits  in  the  town,  as  at  Manchester,  or  deposits  out  of  the  town, 
as  at  Paris.  It  cannot,  except  in  small  towns,  be  removed  directly  to  the  land,  as  the 
demand  is  not  regular.  In  both  cases  the  removal  is  a  great  grievance,  and  the  places  of 
deposit  are  unseemly,  especially  near  Paris,  at  Bondy,  where  a  great  district  becomes  un- 
inhabitable. If  removed  by  water,  either  the  streams  must  be  polluted,  or  sewers  must  be 
carried  along  the  streams  very  far.  If  the  sev.'cr  matter  is  first  disinfected  in  the  sewers, 
it  v.ill  flow  without  disturbing  any  one;  and  if  not  so  much  diluted  with  surface  matter  as 
at  present,  it  might  be  put  at  once  on  the  land,  without  any  one  knowing  by  the  smell  that 
it  differed  from  pure  water. 

Since  Edwin  Chadwick,  C.B.,  and  Dr.  Southwood  Smith,  whether  under  the  name  of  the 
Board  of  Health,  or  Sanitary  Commissioners,  or  other  name,  stimulated  the  countr}'  to 
sanitary  purposes,  the  supply  of  water  and  evei'V  other  progress  relating  to  health  has  un- 
dergone a  great  change.  Professor  Clark  first  showed  the  advantages  of  soft  water ;  and, 
wherever  it  can  be  obtained,  it  is  now  used  in  towns.  Every  town  which  can  obtain  it  has 
now  a  supply  of  water;  and  the  supply  in  many  is  constant. '   The  loss  of  labor  to  a  family 


SANITARY  ECONOMY.  973 

where  water  is  obliged  to  be  carried  from  a  well  is  sometimes  equal  to  that  of  one  person 
for  at  least  one  third  of  a  day.  And  even  with  this  loss  there  is  an  insufficient  supply,  which 
adds  to  the  inconveniences  of  a  household,  and  tiie  loss  of  comfort  and  of  health.  As  towns 
enlarge,  and  as  houses  become  higlier,  the  necessity  for  a  supply  being  introduced  into 
liouses  increases.  In  Glasgow  there  is  a  supply  from  Loch  Katrine,  34  miles  distant.  The 
supply  in  Scotch  houses  must  be  taken  to  the  highest  story  of  the  houses,  on  account  of  the 
system  of  living  in  flats,  and  because  in  the  large  towns  almost  every  family  has  a  water- 
closet  and  a  bath. 

The  cleaning  of  the  surface  of  streets  is  another  important  point  in  sanitary  economy. 
Abundance  of  water  for  this  purpose  would  be  a  great  advantage ;  but  the  plan  is  not  intro- 
duced here.  The  Whitworth  sweeping  machine  was  a  good  cleanser,  but  it  was  very  heavy, 
and  the  cariage  became  expensive.  Hand  sweeping  is  still  resorted  to.  If  disinfecting 
agents  were  put  into  the  water-carts  which  watered  the  streets,  the  putrefaction  going  on 
tliere  in  great  abundance  would  be  arrested,  and  the  disinfected  matter  would  flow  into  the 
sewers,  which  would  then  be  free  from  impure  air,  and  would  run  into  the  river  in  a  state 
that  would  not  corrupt.  This  was  also  proposed,  in  addition  to  the  method  alluded  to  of 
disinfecting  sewers,  and  by  the  same  persons.  After  the  towns  and  their  immediate  neigh- 
bourhoods have  been  purified,  it  is  needful  to  purify  the  land.  The  great  sources  of  mala- 
ria are  not  known;  but  it  is  abundantly  known  that  badly-drained  land,  especially  at  a  high 
temperature,  is  productive  of  malaria;  and  that  even  at  a  moderate  temperature  malaria 
causes  intermittent  attacks.  Drainage  has  greatly  removed  ague  from  this  country ;  it  has 
cleared  the  land ;  and  the  atmosphere  has  become  brighter,  because  the  dried  land  has  not 
produced  so  many  fogs  as  that  which  was  cold  and  wet.  The  clearing  of  swamps  was  a 
labor  of  Hercules,  no  less  valuable  now.  The  agricultural  or  money  value  of  land  has,  at 
the  same  time,  greatly  increased. 

Towns. — It  lias  been  shown  that  a  death-rate  of  22  per  thousand  yearly  prevails  in  Eng- 
1  md,  but  that  in  large  manufacturing  towns  it  rises  to  34,  and  in  certain  parts  of  them  even 
to  4.3,  whilst  in  small  and  healthy  places  it  is  as  low  as  17,  and  in  some  cases  even  less  so. 
The  loss  of  life  is  great,  and  the  loss  of  property  also.  A  great  object  of  sanitary  reformers 
his  been  to  show  that  to  improve  health  has  been  to  improve  property.  There  can  be  no 
doubt  of  it.  Disease  causes  much  loss  of  time  and  labor,  and  diminishes  the  power  of  a 
country  in  which  it  exists.  We  may  very  fairly  calculate  from  the  amount  of  deaths  the 
amount  of  disease.  To  improve  our  health  is  to  improve  our  happiness  and  our  wealth,  as 
well  as  our  capacities  for  both.  Although  in  some  country  places  malaria  may  cause  illness, 
and  ignorance  may  in  various  ways  induce  most  unwholesome  habits,  there  is  les.s  fear  of  dis- 
ease on  an  average  far  from  a  town,  because  of  the  tendency  of  persons  to  live  out  of  doors, 
breathing  pure  air,  for  in  most  places  it  is  pure.  In  towns  we  are  not  only  apt  to  be  more 
shut  up,  and  to  have  less  exercise,  but  we  are  exposed  to  all  the  impurities  which  arise  from 
the  neighborhood  of  multitudes,  as  well  as  from  the  vapors  and  gases  from  manufactures. 
Many  chemists  have  found  it  difficult  to  tell  the  difference  between  town  and  country  air, 
and  have  denied  any  difference ;  but  it  is  now  proved  abundantly.  The  very  rain  of  towns 
where  much  coal  is  burnt  is  so  acid,  tliat  a  drop  falling  on  litmus  renders  it  red.  Blood 
shaken  with  the  air  of  towns  takes  a  different  shade  from  that  shaken  with  pure  air.  The 
air  of  Manchester  contains  about  0-0000934  of  sulphurous  acid,  partly  sulphuric,  into  which 
the  first  changes.  Dr.  Angus  Smith  has  shown  a  method  of  measuring  the  amount  of  im- 
purity in  the  air  by  means  of  a  very  dilute  solution  of  permanganate  of  potash.  His  results 
are  obtained  by  filling  a  bottle  with  the  air  of  the  place,  merely  by  pumping  the  air  out  and 
allowing  the  air  around  to  enter.  A  little  pei'manganate  is  poured  into  the  bottle,  and  it  is 
decolorized ;  more  is  added  until  the  color  remains.  By  this  means  comparative  amounts 
of  oxidiz.ilile  matter  are  readily  measured.  A  pigstye  required  109  measures;  air  from  the 
centre  of  Manchester,  on  an  average  5S ;  air  over  the  Thames,  when  the  putrid  stage  had 
just  passed,  43;  London,  29;  after  a  storm  at  Camden  Town,  12;  fields  near  Manches- 
ter, 13-7;  German  Ocean,  3-3;  Hospice  of  St.  Bernard,  in  a  fog,  28;  Lake  of  Lucerne, 
calm,  1-1.  When  sulphurous  acid  and  sulphuretted  hydrogen  are  present,  the  action  is 
instantaneous:  when  organic  matters  only  are  present,  the  result  is  obtaincii  more  slowly. 
The  dilferenco  between  town  and  country  air  is  remarkable.  The  author  hopes  to  make  the 
experiment  suitable  for  daily  use  in  hospitals.  The  bottle  used  contains  about  KH)  cubic 
inch(!s;  the  solution  of  i)ermanganate  is  graduated  by  a  standard  solution  of  oxalic  acid,  of 
which  1,000  grains  contain  1  of  anhydrous  oxalic  acid.  5  grains  of  this  solution  decompose 
600  grains  of  the  solution  of  permanganate. 

To  prevent  impurities  in  the  air  of  towns  is  extremely  difficult.  Manufactures  must  not 
be  crippled;  certain  noxious  operations  are  not  allowed,  and  complaints  well  substantiated 
against  any  olfensive  works  compel  their  removal.  The  method  of  ab.soibing  noxious  gases 
of  some  kinds  is  now  becoming  usual.  The  coke  towers  for  ab.sorbing  muriatic  acid  began 
a  great  change  in.  this  respect.  They  have  l)een  used  for  sulphuric  acid  itself,  nitrous  fumes, 
suljihurous  acid,  sulphuretted  hydrogen,  Sec.  In  manufacturing  towns  there  is  little  sul- 
phuretted hydrogen — it  is  decomposed  rapidly  by  the  sulphurous  acid.     A  mode  of  absorb- 


974  SANITARY  ECONOMY. 

ing  this  latter  acid  from  coal  smoke  would  be  a  great  blessing  to  all.  But  this  would  not 
remove  all  the  evil ;  coals  send  out  black  soot  in  such  abundance  that  the  whole  of  a  town 
is  darkened,  every  thing  clean  is  made  impure,  and  the  people  find  that  cleaning  is  a  hope- 
less task.  This  might  readily  be  burnt,  but  even  then  we  have  other  difficulties.  Ashes 
rise  up  in  great  amount,  and  fall  do^Ti  again  in  a  perpetual  shower  of  dust.  It  is  these  solid 
matters  as  well  as  the  gases  which  render  our  towns  unwholesome.  If  the  smoke  could  be 
washed  it  would  remove  all  these  evils,  but  the  loss  of  a  draught  to  the  fire  is  then  a  conse- 
quence not  yet  practically  overcome.  When  coals  are  burnt  with  abundance  of  lime,  no 
sulphur  is  given  off",  but  the  use  of  this  cannot  become  general.  We  are  very  much  in  want 
of  a  more  economical  and  wholesome  method  of  obtaining  from  coals  the  power  which  is  in 
them. 

Mr.  Spence,  of  Manchester,  proposes  to  connect  all  the  furnaces  of  the  city  with  the  sew- 
ers, and  thereby  to  burn  the  gases  and  to  ventilate  the  sewers  at  the  same  time.  He  be- 
lieves that  one  chimney  will  ventilate  readily  500  houses,  including  the  house  drains  and 
sewers  also.  > 

The  following  advantages  to  be  derived  from  the  drainage  of  suburban  land  have  been 
mentioned  by  the  Board  of  Health : — 1.  The  removal  of  that  excess  of  moisture  which  pre- 
vents the  permeation  of  the  soil  by  air,  and  obstructs  the  free  assimilation  of  nourishing 
matter  by  the  plants.  2.  Facilitating  the  absorption  of  manure  by  the  soil,  and  so  diminish- 
ing its  loss  by  surface  evaporation,  and  being  washed  away  by  heavy  rains.  3.  Preventing 
the  lowering  of  the  temperature  and  the  chilling  of  the  vegetation,  which  diminishes  the  effect 
of  solar  warmth,  not  on  the  suface  only,  but  at  the  depth  occupied  by  the  roots  of  plants. 
4.  Removing  obstructions  to  the  free  working  of  the  land,  arising  from  the  surface  being  at 
certain  times,  from  excess  of  moisture,  too  soft  to  be  worked  upon,  and  liable  to  be  poched 
by  cattle.  5.  Preventing  injuries  to  cattle  or  stock,  corresponding  to  the  effects  produced 
on  human  beings  by  marsh  miasm,  chills  and  colds,  inducing  a  general  low  state  of  health, 
and  in  extreme  cases  the  rot  or  typhus.  6.  Dimiminishing  damp  at  the  foundations  of 
houses,  cattle  sheds,  and  farm  steadings,  which  cause  their  decay  and  dilapidation,  as  well 
as  discomfort  and  disease  to  inmates  and  cattle. 

The  Board  of  Health,  in  its  excessive  desire  to  remove  all  refuse  by  water,  has  often  ex- 
aggerated the  evils  of  every  other  aid  to  cleanliness.  Water  is  unquestionably  the  best,  but 
it  cannot  always  be  obtained.  In  some  climates  it  is  not  to  be  found  in  abundance,  and  in 
some  weather  it  is  only  to  be  had  by  the  use  of  heat.  When  the  cold  is  great  there  is  no 
fear  of  putrefaction  or  putrid  gases ;  in  warm  places,  or  even  in  temperate,  the  use  of  disin- 
fectants before  removing  the  putiid  matter  is  much  to  be  desired.  The  Board  of  Health 
has  not  feared  to  send  putrid  matter  into  a  river,  believing  it  better  there  than  in  the  town ; 
it  desires  the  water  to  be  put  instantly  on  the  land,  and  to  be  disinfected  by  the  land.  It  is 
well  known  that  the  process  of  doing  this  is  often  offensive.  It  is  also  known  that  large 
quantities  of  this  matter  cannot  be  disposed  of  at  all  times.  It  has  been  said  that  if  the 
liquid  were  diminished  by  the  rain-fall,  it  might  be  manageable.  There  is  another  method 
of  diminishing  its  amount.  At  Carlisle  it  was  found  that  the  water  was  almost  pure  at  certain 
hoXirs  of  the  day,  and  at  all  hours  of  the  night.  By  allowing  the  more  impure  only  to  run 
into  the  sewers,  the  quantity  not  only  becomes  managealile,  but  the  quality  becomes  more 
valualjle.  This  is  an  important  point,  but  one  which  will  probably  be  less  apparent  in  such 
a  place  as  London,  where  the  changes  occurring  from  hour  to  hour  cannot  be  so  great  as  in 
smaller  places.  In  Carlisle  the  sewage  is  deodorized  and  used  on  the  meadows,  and  a  great 
problem  seems  there  and  elsewhere  to  have  begun  its  solution. 

Sanitary  economy  has  proceeded  chiefly  under  the  impression  that  the  pollution  of  the 
air  is  the  evil  most  to  be  dreaded.  That  this  idea  is  correct  there  are  very  many  proofs; 
but  that  there  are  numerous  other  evils  affecting  our  large  towns,  it  is  unwise  to  deny. 
Polluted  air  causes  damp  and  close  cellars,  and  unvcntilated  garrets  and  other  rooms,  to  be 
unwholesome,  as  well  as  all  rooms  without  proper  openings,  without  chimney.s,  and  with- 
out opening  sashes  to  the  windows.  In  a  word,  polluted  air  rises  from  close  places  and  dir- 
ty places;  want  of  light,  too,  is  an  evil  under  which  all  living  creatures  suffer.  Great  and 
crowded  towns  are  subject  most  to  all  these  evils,  but  in  them  also  the  habits  of  the  people 
come  into  consideration.  In  many  of  the  manufacturing  towns  the  people  obtain  much 
larger  wages  than  in  the  country  places,  but  their  houses  are  badly  furnished,  and  their 
clothes,  for  every-day  at  least,  are  extremely  filthy,  whilst  their  love  of  pleasure  is  excess- 
ive. It  is  commonly  supposed  that  the  love  of  pleasure  exists  among  the  rich,  but  it  is  un- 
questionably one  of  the  greatest  evils  oppressinr/  the  poor  in  all  large  towns,  because  their 
cultivation  of  mind  has  not  kept  pace  with  their  knowledge  of  the  external  appliances  of 
civilization. 

A  deficient  intellectual  and  moral  condition  are  the  great  causes  both  of  poverty  and  bad 
health,  for  both  go  together  in  almost  exact  proportions.  It  must  never  be  expected  that 
pure  air  alone  can  make  men  healthy.  The  mind,  as  well  as  the  body,  must  be  freed  from 
irregularities.  Abimdant  wages,  which  are  equal  to  facilities  of  health,  have  rendered  our 
working  classes  inferior  in  some  cases,  both  in  body  and  in  mind,  because  they  have  not 


SEWING  MACHINES. 


975 


Lad  education  to  resist  indulgence.  These  classes  will  often  contrast  badly  with  a  poor  but 
cleanly  ruial  population,  cahn  in  mind,  without  a  desire  for  excitement.  Tlie  subject  is 
here  only  slightly  touched,  it  needs  a  volume :  sanitary  economy,  or  the  metliod  by  which 
man  best  adapts  his  place  of  abode  to  the  conditions  of  external  nature,  must  ever  be  a 
study  of  the  most  absorbing  interest. — R.  A.  S. 

SCOL'KIXG.  This  art  is  tiiat  which  is  employed  for  removing  grease  spots,  &c.,  from 
clothes  and  furniture,  which  require  skill  beyond  that  of  the  laundry.  It  is  divided  into 
two  distinct  branches,  viz.,  Frencli  and  English  cleaning.  We  will  first  give  an  outline  of 
English  cleaning,  although  the  other  (French)  has  no  more  to  do  with  the  French  than  the 
English,  except  in  name ;  and  that  is  kept  because  many  people  would  not  fancy  the  things 
were  done  properly  if  done  by  an  English  process. 

Gentlemen's  clothes,  such  as  trowsers,  coats,  &c.,  are  treated  in  the  following  manner. 
They  are  stretched  on  a  board,  and  the  spots  of  grease,  &e.,  first  taken  out  by  rubbing  the 
spots  well  with  a  brush  and  cold  strong  soap  liquor ;  they  are  then  done  all  over  with  the 
same,  but  the  grease  spots  are  done  first,  because  they  require  more  rubbing,  of  course, 
than  the  other  parts,  and  when  all  the  substance  was  wet  they  would  not  be  so  easily  distin- 
guished. After  treatment  with  the  strong  soap  li(iuor,'  the  soap  is  worked  by  a  weaker  soap 
liquor;  the  articles  are  then  well  washed  off  with  warm  water,  and  treated  with  ammonia, 
{if  0!ack,)  solution  of  common  salt,  or  dilute  acid,  according  to  circumstances.  They  are 
then  drained,  beaten  out  with  a  little  size,  pressed  and  dried. 

Ladies''  articles  of  dress,  as  shawls,  and  woollen  dresses. — The  spots  are  first  removed  by 
rubbing  them  on  the  board  with  very  strong  soap  liquor;  they  are  then  put  into  a  strong 
soap  liquor,  and  well  worked  about  in  it ;  then  taken  out  and  treated  with  a  weaker  soap 
liquor,  to  work  out  the  soap,  &c. ;  rinsed  with  warm  and  cold  water  alternately ;  treated 
with  solution  of  common  salt  or  very  weak  acid,  to  maintain  the  colors.  They  are  starched, 
if  necessary,  and  ironed.  Woollen  dresses  that  are  taken  to  pieces  are  calendered  instead 
of  ironing. 

Silk  dresses,  &c.,  are  always  taken  to  pieces,  and  each  piece  done  separately,  and  as 
quickly  as  possible.  If  there  are  any  spots  of  grease,  they  are  taken  out  first,  as  above 
mentioned.  Each  piece,  after  the  spots  are  removed,  is  immediately  placed  in  a  strong  soap 
liquor,  and  well  worked  about  in  it,  and  then  into  a  thinner  soap  liquor;  well  washed  out 
with  cold  water,  and  treated  with  solution  of  common  salt,  or  very  weak  acid,  or  both,  as 
required ;  each  piece  is  then  neatly  folded  and  wrung  separately,  again  folded  smoothly  and 
placed  in  dry  sheets,  and  pressed,  so  as  to  remove  all  dampness  from  them ;  they  are  then 
put  into  a  frame,  a  little  size  or  sugar  and  water  used  to  stilFen  and  glaze ;  lastly,  dried 
while  on  the  frame  by  a  charcoal  fire. 

Furniture,  as  curtains,  <i'c. — These  things  arc  put  into  a  tub,  with  a  strong  cold  soap 
liquor,  and  well  punched  about  with  a  large  wooden  punch  made  on  purpose ;  and  a  great 
deal  depends  upon  this  being  properly  done.  They  are  then  treated  in  the  same  manner 
in  a  weaker  soap  liquor,  well  rinsed  with  water,  treated  with  common  salt  or  weak  acid,  as 
required,  wrung  out,  and  dried.  Woollen  furniture  will  generally  require  to  be  treated  sev- 
eral times  with  the  first  strong  soap  liquor,  to  remove  the  dirt,  but  for  cotton  furniture  once 
will  generally  be  sufficient. 

Carpets. — These  are  well  beaten,  then  laid  down  on  the  floor  of  the  dye-house,  and  rvell 
scrubbed  with  strong  cold  soap  liquor,  by  means  of  a  long-handled  brush  or  broom;  then 
treated  with  a  weaker  soap  liquor ;  well  rinsed  with  water,  Ijy  throwing  pails  of  water  over 
them,  and  still  rubbing  with  the  brush ;  treated  with  water,  to  which  a  veri^  small  quantitt/ 
of  sulphuric  acid  has  been  added,  to  retain  the  colors;  rinsed  again,  hungup  to  drain,  and 
then  hung  up  in  a  warm  room  to  dry. 

A  great  point  in  this  kind  of  cleaning  is  to  use  strong  cold  soap  liquors;  and  this  can- 
not be  done  with  ordinary  soaps,  as  they  congeal  when  cold,  and  on  this  account  Field's 
soap  is  the  principal  soap  which  is  used,  because  it  is  made  from  oil,  and  does  not  congeal, 
and  I  rather  expect  is  made  from  the  olein  obtained  in  the  manufacture  of  composite  candles. 

French  cleauinef  is  what  is  called  drij  cleaninrj.  In  this  process  the  articles  are  put  into 
camphene  and  worked  about  in  it,  drained,  sheeted,  and  dried.  The  camphene  dissolves 
the  grease,  &c.,  and  does  not  injure  the  colors  ;  but  when  things  are  very  diity,  it  docs  not 
clean  so  effectually  as  the  English  method.  It  is,  however,  the  only  process  that  can  be 
employed  in  some  cases,  as  in  cleaning  kid  gloves. — II   K.  B. 

SELEXITE.     Hydrated  sulphate  of  lime.     See  ALAnASTER  and  Gvrst'M. 

SEWIXG  MACHINES.  The  iiistory  of  these  ingenious  invcntif)ns  has  been  so  well  fold 
by  Professor  Willis,  in  his  report  on  the  machinery  for  woven  frabics  of  the  Paris  Exhibi- 
tion, that  we  do  not  hesitate  to  borrow  from  it. 

At  the  Paris  Exhibition  in  1854,  fourteen  exhibitors  came  provided  with  sewing  ma- 
chines. They  were  of  different  characters,  and  have  been  divided  by  Mr.  Willis  into  four 
classes. 

Under  the  first  class  came  the  machines  in  which  the  needle  is  passed  completely  through 
the  stuff,  as  in  hand  working:  "It  is  so  natural,  in  the  first  attempts  to  make  an  automatic 


976 


SEWING  MACHINES. 


imitation  of  handiwork,  that  the  imitation  shall  be  a  slavish  one,  that  we  need  not  be  sur- 
prised to  find  tlie  earlier  niacliines  contrived  to  grasp  a  common  needle,  push  it  tlirough  the 
stuit"  and  pull  it  out  on  the  other  side." 

Thomas  Stone  and  James  Henderson,  and  some  others,  patented  machines  of  this  kind, 
which  proved  abortive.  M.  Ileilmann  exhibited  an  embroidering  machine  in  1834,  in  which 
"  150,  more  or  less,  of  needles  are  made  to  work  simultaneously,  and  embroider  each  the 
same  flower  or  device  upon  a  piece  of  stuff  or  silk  stretched  on  a  frame  and  guided  by  a  penta- 
graph."  (See  Emdroideuing  Machine.)  Several  embroidering  machines  have  been  from 
time  to  time  introduced. 

The  second  class  of  sewing  machines  was  that  known  as  the  chain-stitch,  or  "  crochet." 
This  is  wrought  by  a  so-called  crochet  needle,  which  terminates  with  a  hook ;  the  needle  is 
grasped  by  tlie  opposite  end,  and  the  hook  pushed  through  tlie  stuff,  so  as  to  catch  hold  of 
a  thread  below,  and,  being  then  withdrawn,  brings  with  it  a  small  loop  of  the  thread  ;  the  hook 
of  the  needle  retaining  this  loop  is  then  repassed  through  the  stuff  at  a  short  distance  in  ad- 
vance of  the  former  passage,  catches  a  new  loop,  and  is  again  witlidrawn,  bringing  with  it 
the  second  loop,  which  thus  passes  through  the  first.  Such  a  series  is  called  chain-stitch, 
and  may  be  used  eitiier  to  connect  two  pieces  together,  or  as  an  eml)roidery  stitch,  for  which  it 
is  well  adapted  fjy  its  ornamental  and  braid-like  appearance.  M.  Thimonnier  patented  in 
18o0  the  first  machine  of  this  character.  M.  Magnin  was  associated  with  Thimonnier  in 
1848  in  a  patent  for  improvements,  and  in  1851  it  was  exhibited  in  London. 

In  184'J  Morey  and  Johnson  patented  a  sewing  machine  in  this  country,  in  which  a  nee- 
dle with  an  eye  near  the  point,  perpendicular  to  the  cloth,  was  combined  with  a  hooked 
instrument  parallel  to  the  cloth,  for  eflecting  the  same  purpose  as  the  crochet  needle.  Mr. 
Singer  improved  on  this,  and  he  introduced  a  contrivance  by  which  his  machine  forms  a 
kind  of  knot  at  every  eighth  .stitch. 

The  third  class  of  sewing  machines  is  wrought  by  two  threads,  and,  as  the  stitch  pro- 
duced by  them  is  known  in  America  as  the  mail-bag  stitch,  it  may  be  presumed  it  was  em- 
ployed IJy  the  makers  of  that  article  before  the  introduction  of  the  machine.  In  the  usual 
mechanical  arrangement  for  its  production,  a  vertical  needle  having  the  eye  very  near  the 
point,  is  constantly  supphed  with  tliread  from  a  bobbin,  and  is  carried  by  a  bar,  which  is 
capal)le  of  an  up-and-down  motion.  The  cloth  being  placed  below  the  needle,  the  latter 
descends,  pierces  it,  and  forms  below  it  a  small  loop,  with  the  thread  carried  down  by  its 
eye.  A  small  shuttle,  which  has  a  horizontal  motion  beneath  the  cloth,  is  now  caused  to  pass 
through  this  loop,  carrying  with  it  its  own  thread.  The  needle  rises,  but  the  loop  is  retain- 
ed by  the  shuttle  thread.  The  cloth  being  next  advanced  through  the  space  of  a  stitch,  the 
needle  descends  again,  and  a  fresli  loop  is  made.  This  process  being  repeated  along  the 
line  of  the  seam,  it  results  that  the  upper  thread  sends  down  a  loop  through  such  needle 
hole,  and  that  the  lower  thread  passes  through  all  these  loops,  and  thus  secures  the  work. 
The  first  macliine  for  producing  this  stitch  was  invented  by  Walter  Hind,  of  New  York,  in 
1834.  Several  patents  for  producing  this  stitch  have  been  obtained.  Howe's  patent  was 
one  of  the  most  practical.  Mr.  Thomas  of  London  became  the  possessor  of  Howe's  patent. 
This  was  improved;  and  a  new  patent  obtained  in  June,  1846,  which  was  modified  in  De- 
cember of  that  year.  This  machine  has  been  extensively  used.  This  invention,  says  the 
patentee,  consists  in  certain  novel  arrangements  of  machinery,  whereby  fabrics  of  various 
textures  may  be  sewn  together  in  such  a  manner  as  to  produce  a  firm  and  lasting  seam. 
By  this  invention  a  shuttle,  when  the  point  of  the  needle  has  entered  the  cloth  or  other  fab- 
ric under  ojieration  and  formed  a  loop  of  thread,  passes  through  that  loop  and  leaves  a 
thread  on  the  face  of  the  cloth,  by  which  means  the  needle  when  it  is  withdrawn  from  the 
cloth,  instead  of  drawing  back  the  thread  with  it,  leaves  'a  tightened  loop  on  the  opposite 
side  of  the  cloth  to  that  at  which  it  entered.  The  fabric  then  passing  forward  to  the  dis- 
tance of  the  length  of  the  stitch  recpiired  is  again  pierced  with  the  needle,  and  a  stitch  is  in 
like  manner  produced.  A  drawing  of  this  machine  is  shown  in  Jig.  007,  which  will  be  un- 
derstood from  the  following  description. 

1.  TTie  needle.  Place  tlie  needle  in  the  slide  a,  with  its  flat  side  towards  the  shuttle,  and 
the  grooved  side  in  front.  Turn  the  wheel  of  the  machine  round  till  the  line  //  on  the  gun- 
metal  slide  is  level  with  the  line  g  on  the  iron  cheek.  Place  the  eye  of  the  needle  level  \^\\\\ 
tiie  to])  of  the  shuttle  box,  and  screw  the  needle  fast. 

2.  If  the  eye  is  above  the  box  when  the  marks  correspond,  the  needle  is  too  high  ;  if 
the  eye  cannot  be  seen,  the  needle  is  too  low. 

3.  The  needle  should  jjass  down  the  centre  of  the  hole  in  the  shuttle  box  ;  but  if  it  does 
not,  it  can  be  made  to  do  so  by  bending. 

4.  Ilie  vccdlc  thread  runs  from  the  top  of  the  reel,  through  the  rings  n,  c,  and  through 
the  eye  of  the  needle. 

5.  Tlie  shuttle.  It  is  necessary  that  the  first  coil  of  cotton  be  wound  closely  on  the  bob- 
bin, or  it  will  be  diflicult  to  make  it  lie  side  by  side  like  that  on  ordinary  reels.  The  reels 
should  not  be  fille<l  al)ove  the  brass,  and  the  cotton  or  silk  should  be  free  from  knots,  which 
sometimes  pull  the  wire  out  of  the  shuttle. 


SEWING  MACniNES. 

607 


977 


6.  The  thread  must  run  from  the  under  side  of  the  bobbin,  round  the  wire  and  out  through 
holes  Nos.  1,  2,  and  3.  If  the  thread  is  not  tight  enough,  miss  No.  3,  and  let  it  come  out 
through  Xo.  -1  or  5,  or  it  may  be  drawn  through  five  holes.  Put  the  shuttle  in  the  box, 
turn  the  wheel  round  once,  then  pull  the  end  of  the  needle  thread  and  draw  up  the  shuttle 
thread  through  the  hole  in  the  plate.  Place  the  cloth  under  the  mover,  and  the  machine  is 
ready  for  work.  The  proper  time  for  turning  the  work  to  sew  a  corner,  &c.,  is  when  the 
spring  at  the  top  is  lifted  off. 

7.  The  length  of  stitch  is  regulated  by  the  screw  e  at  back  of  machine. 

8.  The  tightness  of  the  needle  thread  is  regulated  by  the  screw  f. 

9.  The  tightness  of  the  shuttle  thread  is  regulated  by  passing  the  thread  through  more 
or  less  holes. 

10.  The  quantity  of  thread  pulled  off  the  reel  for  each  stitch  is  regulated  by  the  position 
of  the  piece  of  brass  b.  The  lower  the  hole  at  its  end  the  greater  the  quantity  pulled  off: 
when  the  cloth  is  thick,  more  thread  is  used,  and  the  end  of  the  brass  b  should  be  lowered ; 
when  thin,  raised.  It  should  be  in  such  a  position  that  the  trumpet  c  is  drawn  nearly  do^\"ii 
to  the  pin  on  the  slide  when  the  shuttle  passes  through  the  loop. 

A  patent  was  obtained  by  John  Thomas  Jones,  of  Glasgow,  in  February,  1 850,  for  a 
sewing  machine  presenting  many  novelties  and  improvements.  Mr.  Jones'  patent  well  ex- 
plains his  machine ;  we  therefore  transfer  his  description  to  our  pages. 

The  machine  consists,  under  one  modification,  of  an  open  frame,  having  a  platform  top 
upon  which  the  sewing  or  stitching  operations  are  carried  on.  Beneath  this  platform,  and 
near  one  end  of  it,  is  a  short  transverse  horizontal  first  motion  shaft  running  in  bearings  in 
the  framing  and  carrying  a  long  crank,  a  connecting  rod  from  whicli  is  jointed  at  its  op- 
posite end,  directly  to  the  .shuttle  driver  or  slide  piece,  working  in  a  horizontal  guide  recess 
beneath  the  opposite  or  front  end  of  the  platform  or  table.  The  first  motion  shaft  has  also 
another  and  shorter  crank  upon  it,  the  stud  pin  of  wiiich  is  connected  to  the  pin  of  the 
longer  crank  by  an  overhanging  link  jjiece,  provision  being  made  for  the  adjustment  of  the 
relative  positions  of  the  two  cranks  as  regards  their  sequence  of  revolution.  It  is  this 
shorter  crank  which  actuates  the  needle  movement,  the  pin  being  entered  into  a  differen- 
tially slotted  or  operated  cam  piece,  forming  the  pendent  lower  end  of  a  bent  lever,  working 
on  a  stud  centre,  in  the  interior  of  the  overhead  bracket  or  pillar  arm  of  the  framing.  The 
centre  on  which  this  lever  works  is  in  the  horizontal  part  of  the  overhead  bracket  arm,  and 
its  opposite  or  free  working  end  has  a  rectangular  slot  in  it  to  embrace  a  rectangular  block 
of  metal  working  freely  upon  a  lateral  centre  stud  upon  the  vertical  needle-carrying  bar. 
In  this  way  the  needle  has  imparted  to  it  a  differential  rociprocatory  vertical  movement,  the 
peculiar  connection  of  the  needle  bar  with  the  actuating  lever  having  the  effect  of  marking 
the  needle  in  the  most  accurate  manner,  and  preventing  jarring  and  wear.  These  are  the 
whole  of  the  primary  movements  for  working  tlic  stitches,  which  may  be  of  various  kinds, 
'as  made  up  from  the  combined  action  of  the  needle  anil  sliuttle,  or  thread-carrier ;  the  form 
of  the  slotted  piece  or  ojierated  cam  in  the  end  of  the  needle  lever,  being  variable  to  suit 
any  required  peculiarity  of  needle  movement,  tiie  main  elements  of  which  arc  a  direct  up- 
and-down  motion  without  a  stop  or  rest,  until  at  tlie  termination  of  tiie  down  stroke,  when 
a  short  rise  takes  place,  succeeded  by  a  rest  to  allow  of  the  due  looping  and  stitching  of 
the  thread.  The  feed  of  the  fabric  to  be  sewed  is  eilectcd  by  the  operation  of  a  short  verti- 
VoL.  III.— G2 


978 


SILVER,  ASSAY  FOR. 


cal  lever  piece  with  a  cranked  and  slotted  lower  end,  where  it  is  set  on  a  fixed  stud  in  the 
framing.  This  feed  lever  has  a  roughened  or  toothed  upper  end,  the  teeth  or  asperities 
being  set  or  inclined  in  the  direction  of  the  fabric's  traverse.  After  each  stitching  action, 
the  feed  lever  being  lowered  just  beneath  the  operating  level,  is  raised  up  so  as  to  press 
firmly  against  the  under  side  of  the  fabric,  and  nip  it  between  the  stationary  spring  pressed 
above.  This  elevation  of  the  roughened  face  is  effected  by  the  traverse  of  the  shuttle- 
carrier,  which  at  its  back  stroke  comes  against  the  inclined  tail  of  a  short  horizontal  lever 
set  on  a  stud  in  the  framing,  and  having  its  opposite  bent  end  bearing  against  the  lower 
end  of  the  feed  lever,  at  the  part  where  it  is  carried  by  its  slot  upon  the  holding  stud.  At 
the  commencement  of  the  return  of  the  shuttle,  an  inclined  piece  upon  the  shuttle  carrier 
bears  against  a  lateral  stud  upon  one  end  of  a  short  rocking  or  oscillatory  shaft  set  in  bearings 
in  the  framing,  the  other  end  of  the  shaft  having  a  lever  arm  bearing  against  the  side  of  the 
feed  lever.  In  this  way  the  feed  lever  is  traversed  forward  in  its  elevated  position,  carrying 
forward  the  fabric  for  the  succeeding  stitch.  The  adjustment  of  the  spring  presser  is  effect- 
ed by  an  upper  screw  in  the  end  of  the  bracket  arm  of  the  framing,  the  lower  end  of  the 
screw  bearing  upon  a  lateral  pressing  piece  which  rests  or  abuts  on  the  top  end  of  a  flatten- 
ed helical  spring  upon  the  presser  bar.  The  latter  can  be  set  up  clear  out  of  work  by 
means  of  a  small  cam  lever  set  on  a  stud  in  the  stationary  guide  of  the  presser  bar,  the  cam 
bearing  against  a  lateral  stud  in  the  bar,  so  that  by  setting  the  lever  up  or  down,  the  cam 
is  correspondingly  turned,  and  the  lever  set  up  or  down,  as  required.  The  actual  pressing 
or  re.sisting  foot  of  the  bar  is  a  bent  piece  of  metal  screwed  on  to  the  bar,  and  being  thus 
removable  to  allow  of  various  forms  of  feet  guides,  or  presser  surface  pieces,  being  put  on 
to  suit  vai-ieties  of  forms  of  stitching. 

This  machine,  or  a  modification  of  it,  is  available  for  working  a  duplex,  or  other  stitch- 
ing action,  without  involving  further  modification  of  the  prime  movers.  In  working  a  du- 
plex arrangement,  two  needles  and  two  shuttles  are  used,  each  needle  and  shuttle  working 
independently,  so  as  to  allow  of  sewing  in  two  different  and  independent  lines  with  one  set 
of  actuating  parts.  To  aid  the  shuttle  action  there  is  attached  to  its  side  a  flat  curved  blade 
spring,  one  end  of  which  is  free,  but  hooked  into  a  hole  in  the  body  of  the  shuttle.  Thus, 
ds  the  shuttle  traverses  forward,  the  sewing  thread  is  drawn  beneath  the  hooked  end  portion 
of  the  spring,  so  as  to  be  nipped  against  the  shuttle.  The  thread  is  thus  held,  and  the 
proper  loop  is  secured  at  the  part  immediately  outside  the  nipped  portion.  With  this 
arrangement  the  needle  can  never  work  on  the  wrong  side  of  the  shuttle  thread.  Provision 
is  also  made  for  securing  an  independent  shuttle  thread  controller.  This  is  a  nipper  or  re- 
tainer worked  from  any  convenient  part  of  the  mechanism,  but  entirely  independent  of  the 
shuttle  movement.  This  may  be  aiTanged  in  various  ways,  the  oljject  being  the  variable 
and  efficient  control  or  retention  of  the  thread,  without  interfering  in  any  way  with  the 
fixed  and  determined  action  of  the  shuttle.  Instead  of  fixing  a  horizontal  shuttle  race,  or 
guide  track,  in  the  framing,  the  shuttle  driver  is  itself  made  the  race  or  carrier,  so  as  to 
secure  both  offices  in  one  detail  or  arrangement.  A  hook  or  finger,  actuated  by  any  con- 
venient part  of  the  movement,  is  also  used  for  retaining  the  needle  thread  for  any  desired 
time  after  being  passed  through  the  fabric ;  this  facilitates  the  movement  or  action  of  the 
needle  bar.  The  .shuttle  race,  when  one  is  used,  is  made  quite  independent  of  the  machine, 
so  that  it  can  be  changed  at  any  time  to  suit  various  sized  shuttles  by  merely  slipping  in  or 
taking  out  the  part.  The  portion  of  the  framing  carrying  the  shuttle  race  is  cast  in  one 
piece  with  the  main  body  of  the  platform,  but  the  table  or  plate  on  which  the  stitching 
takes  place  is  a  loose  piece  slotted  down  the  middle  for  the  working  movements,  and  fitted 
into  its  position  by  pins  cast  upon  it,  and  entered  into  corresponding  recesses  in  the  main 
base. 

There  exi.sts  a  fourth  class  of  sewing  machines,  which  produce  more  complex  stitches 
than  the  preceding.  These  are  formed  by  sewing  two  threads,  which  mutually  interlace 
each  other  in  chain  stitch,  so  as  to  avoid  the  unravelling  to  which  the  simple  chain  stitch  is 
subject,  and  also  are  intended  to  meet  an  objection  which  is  urged  against  the  shuttle  stitch 
machines,  on  the  ground  that,  as  the  shuttle  must  be  small  to  enable  it  to  pa.«s  through  the 
loop  formed  by  the  needle  tlnead,  so  the  bobbin  carried  by  the  shuttle  can  only  obtain  a 
moderate  length  of  thread.  Thus  the  operation  is  stopped  at  short  intervals  to  sujiply  fresh 
bobbins  to  the  shuttle.  Several  patents  have  been  obtained  for  compound  chain  stitch 
machines;  two  in  America,  in  1851  and  1852,  by  Grover  and  Baker;  another  in  1852  by 
Avery  ;  and  another  by  M.  Journaux  Le  Blond. 

Mr.  Willis,  in  concluding  his  report,  very  justly  remark.'!,  "In  England,  as  in  Franct, 
all  the  most  promising  American  patents  have  been  rcpatented,  and  the  use  of  the  machine 
appears  to  be  slowly  and  gradually  extending  itself  The  sewing  machine  is  doubtlc.«6  yet 
in  its  infancy  ;  but  it  has  acfjuired  so  prominent  a  position,  and  shown  itself  to  be  so  useful, 
as  to  deserve  the  time  and  attention  of  able  mechanists.  Its  imperfections  will  therefore 
be,  if  possible,  gradually  removed,  and  it  may  take  its  place  in  the  series  of  manufacturing 
mcclianism  as  a  most  useful  agent." 

SILVER,  ASSAY  FOR.     Estimation  of  silver  containcdin  lead  ores.     Many  varieties 


SILVER,  ASSAY  FOR.  979 

of  lead  ore  contain  silver,  and  it  is  consequently  necessary,  in  order  to  judge  of  their  com- 
mercial value,  to  ascertain  the  exact  amount  of  this  metal  which  they  atl'ord.  Tiiis  is  ett'ect- 
ed  by  tlie  process  of  cupellation  :  an  operation  founded  on  the  fact  that  when  an  alloy  of 
lead  and  silver  is  exposL'd  to  a  current  of  air,  when  in  a  state  of  fusion,  the  silver  neitlier 
gives  off  perceptible  vapors  nor  becomes  sensibly  oxidized,  wliilst  the  lead  rapidly  absorbs 
oxygen  and  becomes  converted  into  a  fusible  oxide. 

In  order  therefore  to  separate  tlie  silver  that  may  be  present  in  buttons  resulting  from 
ordinary  lead  assays,  it  is  only  necessary  to  expose  them  on  some  suitable  porous  medium, 
to  such  a  temperature  as  will  rapidly  oxidize  the  lead.  The  litliarge  produced  is  aborijed 
by  the  porous  body  on  which  tlie  assay  is  supported,  and  nothing  but  a  small  button  of 
silver  ultimately  remains  on  the  test.  These  supports  or  cupels  are  made  of  bone-ash, 
slightly  moistened  with  a  little  water,  and  consolidated  by  being  pressed  into  a  mould.  The 
furnace  employed  for  this  purpose  is  described  in  the  article  Assay,  vol.  i. ;  as  is  also  the 
mujjie  or  D-shaped  retort  in  which  the  cupels  are  heated. 

As  soon  as  the  muffle  has  become  red  hot,  six  or  eight  cupels  that  have  been  drying  in 
the  mouth  of  the  opening  are  introduced  by  means  of  proper  tongs,  and  the  bottom  of  the 
muffle  is  covered  witli  a  thin  layer  of  bone-ash,  in  order  to  prevent  its  being  attacked  in 
case  of  any  portion  of  litharge  coming  in  contact  with  it  during  the  progress  of  the  subse- 
quent operations.  The  open  end  of  the  muffle  is  now  closed  by  means  of  a  proper  door, 
and  the  cupels  are  thus  rapidly  heated  to  the  temperature  of  the  muffle  itself.  When  this 
has  been  etfected  the  door  is  removed,  and  into  each  of  the  cupels  is  introduced  by  the  aid 
of  slender  steel  tongs  a  button  of  the  lead  to  be  assayed.  The  mouth  of  the  muffle  is  again 
closed  during  a  few  minutes  to  facilitate  the  fusion  of  the  alloy,  and  on  its  removal  each 
of  the  cupels  will  be  found  to  contain  a  bright  metallic  globule,  in  which  state  the  assay  is 
said  to  be  uncovered.  The  lead  is  now  quickly  converted  into  litharge,  which  is  absorbed 
by  the  cupel  as  fast  as  it  is  produced,  whilst  at  the  same  time  there  arises  a  white  vapor 
that  fills  the  muffle  and  is  gradually  carried  off  by  the  door  and  through  the  openings  in  the 
sides  and  end.  A  circular  stain  is  at  the  same  time  formed  around  the  globule  of  metal, 
which  gradually  extends  and  penetrates  into  the  substance  of  the  cupel.  When  nearly  the 
whole  of  the  lead  has  thus  been  removed,  the  remaining  bead  of  alloy  appears  to  become 
agitated  by  a  rapid  motion,  which  seems  to  make  it  revolve  with  great  rapidity.  At  this 
stage  the  motion  will  be  observed  suddenly  to  cease,  and  the  button,  after  having  for  an 
instant  emitted  a  bright  flash  of  light,  becomes  immovable.  This  is  called  the  brightening 
of  the  assay,  and  a  button  of  silver  now  remains  on  the  cupel. 

If  the  cupel  were  now  abrupty  removed  from  the  muffle,  the  metallic  globule  would  be 
liable  to  vegetate,  by  which  a  portion  of  the  metal  might  be  thrown  o!f,  and  a  certain 
amount  of  loss  be  thereby  entailed.  To  prevent  this,  the  cupel  in  whic'.i  the  assay  has 
brightened  should  be  immediately  covered  by  another,  kept  red  hot  for  that  purpose.  The 
two  are  now  gradually  withdrawn  together,  and,  after  having  sufficiently  cooled,  the  upper 
cupel  is  removed,  and  the  globule  of  silver  detached  and  weighed. 

From  the  fact  that  silver  becomes  sensibly  volatile  at  very  elevated  temperatures,  it  be- 
comes necessary  to  make  cupellations  of  this  metal  at  the  lowest  possible  heat  at  which  they 
can  be  effected.  The  temperature  best  fitted  for  this  operation  is  obtained  when  the  muffle 
is  at  a  full  red  heat,  and  the  vapors  which  arise  from  the  assays  curl  gradually  away,  and  are 
finally  removed  by  the  draught.  When  the  muffle  is  heated  to  whiteness,  and  the  vapors 
rise  to  the  top  of  the  arch,  the  heat  is  too  great ;  and  when,  on  the  contrary,  the  fumes  lie 
over  the  bottom,  and  the  sides  of  the  openings  in  the  muffle  begin  to  darken,  either  a  little 
more  fuel  must  be  added  or  the  draught  increa.sed. 

If  an  assay  has  been  properly  conducted,  the  button  of  silvei-  Obtained  is  round,  bright, 
and  smooth  on  its  upper  surface,  and  beneath  should  be  crystalline  and  of  a  dead-white 
color ;  it  is  easily  removed  from  the  cupel,  and  readily  freed  from  litharge.  The  globule  is 
now  laid  hold  of  by  a  pair  of  fine  pliei-s  and  flattened  on  a  small  steel  anvil,  by  wiiich  the 
oxide  of  lead  which  may  have  attached  itself  to  it,  becomes  pulverized,  and  is  removed  by 
rubbing  with  a  small  hard  brush.  The  flattened  disc  is  then  examined,  in  order  to  be  sure 
that  it  is  perfectly  clean,  and  afterward  weighed  in  a  balance  capable  of  turning  with  one- 
thousandth  of  a  grain. 

The  fuel  employed  consists  of  hard  coke  broken  into  small  pieces. 

When  the  ores  of  lead,  in  addition  to  silver,  contain  gold,  the  button  remaining  on  the 
cupel  id  an  alloy  of  these  metals. 

'  For  commercial  purposes,  the  silver  contained  in  any  given  ore  or  alloy  is  estimated  in 
ounce.'*,  pennyweights,  and  grains,  one  ton  of  ore  or  alloy  being  usually  taken  as  the  stand- 
ard of  unity. 

Asuai/  of.nh'cr  ores  not  containing  lead. — In  the  assay  of  ores  belonging  to  this  clas.«i, 
it  is  usual  to  obtain  the  silver  they  afford  in  the  form  of  an  alloy  with  lead;  and  this  is 
subsequently  pa.ssed  to  the  cupel  in  the  ordinary  way. 

Ores  of  silver  in  which  the  metals  exist  in  the  form  of  oxides  are  commonly  fused  with 
a  mixture  of  litharge,  red  lead,  and  powdered  charcoal,  by  which  an  alloy  of  lead  is  obtain- 


9b0 


SILVER,  ASSAY  FOR. 


ed,  which  is  afterwards  treated  by  cupellation.  The  amount  of  litharge  employed  must  be 
varied  according  to  circumstances,  as  the  resulting  button  should  not  be  too  small,  since  in 
that  case  a  portion  of  the  silver  might  be  lost  in  the  slag  ;  nor  too  large,  as  the  cupellation 
would  then  occupy  a  long  time,  and  a  loss  through  volatilization  be  the  result. 

In  most  cases,  if  400  grains  of  ore  be  operated  on,  a  button  of  200  grains  will  be  a  con- 
venient weight  for  cupellation  ;  this  may  be  obtained  by  the  addition  of  400  grains  of  lith- 
arge, and  from  7  to  8  grains  of  pulverized  charcoal.  This  is  to  be  well  mixed  with  200 
grains  of  carbonate  of  soda,  and  introduced  into  an  earthen  crucible,  of  which  it  should  not 
fill  more  than  one-half  the  cai)acity.  This  is  covered  by  a  layer  of  borax,  and  fused  in  the 
a.ssay  furnace,  taking  care  to  remove  it  from  the  fire  as  soon  as  a  perfectly  li(iuid  slag  has 
been  obtained,  since  the  unreduced  litharge  might  otherwise  cut  through  the  crucible  and 
si)oil  the  assay.  When  cold,  the  pot  Ts  broken,  and  the  button  cupelled  in  the  ordinary 
way. 

In  this,  and  all  other  similar  experiments,  it  is  necessary  to  ascertain  the  proportion  of 
silver  contained  in  the  lead  obtained  from  the  litharge  used,  in  order  to  make  the  re- 
quisite deduction  from  the  results  obtained.  When  fine  litharge  is  emj^loyed  the  resulting 
lead  contains  so  small  an  amount  of  silver,  that  for  many  commercial  purposes  it  may  be 
disregarded. 

When  other  minerals  than  oxides  are  to  be  examined,  the  addition  of  charcoal  becomes 
in  many  cases  unnecessary,  since  litharge  readily  attacks  all  the  sulphides,  arsenio-sulphides, 
&c.,  and  oxidizes  many  of  their  constituents,  whilst  a  proportionate  quantity  of  metallic 
lead  is  set  free.  The  slags  thus  formed  contain  the  excess  of  litharge,  and  the  Ijutton  of 
alloy  obtained  is  cupelled.  The  proportion  of  oxide  of  lead  to  be  added  to  ores  of  this  de- 
scription varies  in  accordance  with  the  amounts  of  oxidizable  substances  present ;  but  it 
must  always  be  added  in  excess  in  order  to  prevent  any  chance  of  loss  of  silver  from  the 
action  of  sidphidcs  in  the  slags. 

The  only  objection  to  this  method  of  assay  is  the  large  quantity  of  lead  produced  for 
cupellation — since  iron  pyrites  afford  by  the  reduction  of  the  litharge  8\  parts  of  lead,  whilst 
sulphide  of  antimony  and  gray  copper  ore  yield  from  6  to  7  parts.  This  inconvenience  may 
be  obviated  by  the  previous  oxidation  of  the  mineral,  cither  by  roasting,  or  by  the  aid  of 
nitre,  by  the  judicious  employment  of  which  buttons  of  almost  any  required  weight  may  be 
obtained. 

Should  this  reagent  be  employed  in  excess,  it  would  cause  the  oxidation  of  all  the  metal- 
lic and  combustible  substances  present,  not  even  excepting  the  silver. 

When,  however,  the  mixture  contains  at  the  same  time  a  large  excess  of  litharge  and 
the  quantity  of  nitre  added  is  not  sufficient  to  decompose  the  whole  of  the  sulphides,  a  re- 
action takes  place  between  the  undecomposed  sulphide  and  the  oxide  of  lead  added,  which 
gives  rise  to  the  formation  of  metallic  lead,  and  this  combining  with  the  silver,  affords  a 
button  of  alloy,  which  may  be  treated  by  cupellation. 

The  quantity  of  nitre  to  be  used  for  this  purpose  will  depend  on  the  nature  and  richness 
of  the  ores  under  examination  -,  but  it  must  be  remembered  that  21  parts  of  nitre  will  de- 
compose and  completely  oxidize  pure  iron  pyrites,  whilst  1^  and  Jds  of  its  weight  are  in 
the  case  of  sulphide  of  antimony  and  galena  respectively  sufficient. 

In  cases  when  the  excess  of  sulphur  present  is  very  great,  a  partial  roasting  of  the  ore 
is  preferable  to  the  addition  of  a  large  quantity  of  nitre. 

Instead  of  operating  according  to  any  of  the  processes  above  described,  it  is  sometimes 
found  advantageous  to  expel  the  whole  of  the  arsenic  and  sulphur  by  a  careful  roasting, 
and  then  to  fuse  the  residue  with  a  mixture  of  litharge,  carbonate  of  soda,  and  borax,  taking 
care  to  adtl  a  sufficient  amount  of  some  reducing  flux  to  obtain  a  button  of  convenient  size. 

When  in  addition  to  silver  the  mineral  operated  on  contains  gold,  the  button  obtained 
by  cupellation  will  consist  of  a  mixture  of  these  metals,  which  may  be  separated  by  the  aid 
.  of  nitric  acid. 

Scorifieation. — Instead  of  operations  as  above  described,  silver  ores  are  sometimes  treat- 
ed by  scorification.  In  that  case,  they  are  mixed  with  granulated  lead  and  exposed  in  small 
refractory  saucers  to  a  strong  heat  in  an  ordinary  muffle  furnace.  After  a  sufficient  amount 
of  tli€  lead  has  become  oxidized,  and  the  resulting  litharge  has  formed  a  fusible  slag  with 
the  gangue  of  the  ore,  the  metallic  lead  is  poured  into  a  suitable  mould,  and  afterwards 
subjected  to  cupellation.  When  the  granulated  lead  employed  for  this  purpose  contains 
silver,  dfie  allowance  for  its  presence  must  be  made  in  the  result  obtained. 

Simple  process  for  the  reduction  xilver  to  a  metallic  state  bi/  mentis  of  sugar. — ^The  silver 
of  coin  is  first  reduced  to  the  state  of  chloride,  and  the  weight  of  the  alloy  thus  ascertained ; 
the  chloride,  after  having  been  well  washed  and  freed  from  copper,  is  to  be  put  into  a  stop- 
pered wide-necked  bottle  ;  a  fjuantity  of  refined  sugar,  or  sugar-candy,  is  then  added,  equal 
in  weight  to  the  alloy.  This  is  mixed  with  an  equal  volume  of  a  solution,  composed  of  00 
grammes  of  good  hydrate  of  pota.sh,  and  150  grammes  of  distilled  water,  which  will  yield 
solution  of  pota.sh  of  25'  Beaume,  or  thereabouts:  after  closing  the  bottle  the  mixture  is  to 
be  agitated,  and  then  left  for  24  hour.s,  shaking  it  occasionally,  to  favor  the  reaction.     After 


SOAP.  981 

this  period  has  elapsed,  it  is  to  be  washed  several  times,  until  the  last  washings,  filtered,  are 
not  aCFected  by  nitrate  of  silver — a  test  which  should  be  preceded  by  that  of  red  litmus 
paper,  which  ought  not  to  become  blue,  or  show  any  change  whatever.  This  done,  the 
contents  of  the  bottle  are  to  be  transferred  to  a  porcelain  capsule,  by  the  help  of  a  little 
distilled  water;  then,  after  being  allowed  to  deposit,  the  excess  of  liquid  is  poured  ofT,  and 
the  silver  diied  in  a  stove. 

By  these  means  we  obtain  that  to  which  Dr.  Ure  gave  the  name  of  r/ray  silver.  This 
silver  consists  of  some  bright  spangles,  which  become  more  brilliant  on  friction.  It  does 
not  contain  any  impurities,  with  the  exccptijn  of  a  small  quantity  of  oxide,  and  a  few  atoms 
of  chloride  of  silver.  This  latter  produces  a  slight  turbidity  in  the  liquor,  when  dissolved 
in  perfectly  pure  nitric  acid,  and  diluted  with  distilled  water.  This  turbidity  does  not,  how- 
ever, prevent  the  formation  of  pure  nitrate  of  silver;  as  the  chloride  being  only  in  suspen- 
sion in  the  liquid,  it  is  sulficient  to  filter  it  on  a  small  portion  of  well  washed  asbestos,  in 
order  to  obtain  an  unobjectionable  liquor.  The  nitrate  of  silver  will  not  contain  any  trace 
of  other  metals,  as  none  are  used  in  the  reduction  of  the  chloride  of  silver,  and  by  the  re- 
duction of  this  salt  the  silver  is  completely  separated  from  the  iron  and  copper  which  the 
solution  might  contain.  Thus  the  nitric  acid  of  commerce  may  be  employed,  without 
inconvenience,  for  dissolving  the  allo.v. 

The  gray  silver  almost  always  contains  a  small  quantity  of  oxide;  this  is  easily  verified 
by  the  addition  of  ammonia,  which,  after  digestion  on  the  metal  and  filtration,  produces  a 
slight  turbidity  on  adding  nitric  acid,  which  is  caused  by  the  separation  of  the  dissolved 
chloride  of  silver;  the  turljidity  is  then  increased  by  the  addition  of  a  small  quantity  of 
chloride  of  sodium  to  the  nitrate  of  ammonia  previously  formed  ;  thus,  then,  is  the  oxide 
of  silver  dissolved  in  the  liquor  in  the  state  of  ammoniacal  nitrate,  which  is  precipitated  in 
the  form  of  insoluble  chloride. 

Oxida  of  silver  not  being  an  impurity  in  the  uses  to  which  pure  silver  is  applied  in 
laboratories,  we  may  consider  the  grai/  silver  obtained  in  the  manner  above  described  as 
more  pure  and  with  less  loss  than  any  of  those  prepared  up  to  the  present  time,  by  the 
reduction  of  chloride  of  silver  ;  and  without  the  necessity  of  melting.,  a  troublesome  operation, 
and  one  of  much  inconvenience  in  a  laboratory. 

SO -IP  is  a  chemical  compound,  muiufaetured  on  a  very  extensive  scale,  forming,  accord- 
ingly, a  considerable  article  of  commerce.  It  is  a  compound  resulting  from  the  combina- 
tion of  certain  constituents  derived  from  fats,  oils,  grease  of  various  kinds,  both  animal  and 
vegetable,  with  certain  salifiable  bases,  which,  in  detergent  soaps,  are  potash  or  soda. 

Oils  and  fats  consist  chiefly  of  oleine  and  stearine,  as  in  tallow,  suet,  and  several  vege- 
table fats;  of  margarine,  which  occurs  in  animal  fats,  in  butter,  in  olive  and  other  vegetable 
oils ;  of  palmitine,  which  is  found  in  palm  oil,  and  so  on  with  various  other  immediate  prin- 
ciples, according  to  tlie  nature  of  the  fats  and  oils  employed  by  the  soap-maker.  Natural 
fatty  substances,  however,  are  never  exclusively  formed  of  one  of  these  principles;  but  are, 
on  the  contrary,  composed  of  several  of  them  in  various  proportions,  oleine  alone  being  a 
cjnstant  constituent  in  all  of  them. 

Natural  or  neutral  fats  and  oils,  chemically  considered,  are  really  salts,  sometimes  called 
"glycerydes,"  that  is  to  say,  are  combinations  of  acids,  oleic,  stearic,  margaric  acid,  &c., 
witli  the  oxide  of  a  hypothetical  radical  gli/ceryle,  (sweet  principle  of  oil.s.) 

Stearine  being,  therefore,  a  combination  of  stearic  acid  with  oxide  of  glyeeryle,  is  a  ste- 
arate  of  oxide  of  glyeeryle. 

Oleine  is  a  combination  of  oleic  acid  with  oxide  of  glyeeryle,  and  is,  therefore,  an  oleate 
of  oxide  of  glyeeryle. 

Margarine  is  a  combination  of  margaric  acid  and  oxide  of  glyeeryle,  and  is,  therefore, 
a  margarate  of  oxide  of  glyeeryle,  and  so  on  with  the  other  constituents  of  fats  and  oils. 

Glycerine  is  a  combination  of  oxide  of  glyeeryle  with  water,  which,  in  that  case,  plays 
the  pait  of  an  acid  to  form  a  hydrate  of  oxide  of  glyeeryle,  (glycerine.) 

Now,  when  neutral  fats  (namely,  oleine,  stearine,  margarine,  &e.,  or  the  fats  or  oils 
which  they  constitute)  are  treated  by  solutions  of  caustic  alkalies,  such  as  pota.«h  or  soda, 
their  constituents  react  upon  eaeli  other,  and  combine  with  the  potash  or  soda ;  and  pro- 
vided too  great  an  excess  of  alkali  ha.■^  not  been  used,  tlic  fat  or  oil  dissolves  in  the  alkaline 
solution  into  a  syrupy  liquid,  whicli  on  cooling  forms  a  gelatinous  mass,  which  is  nothing 
else  than  an  aqueous  solution  of  soap  mixed  witli  ttie  glycerine,  whicii  tlio  trcatmont  basset  free. 

The  following  equation,  in  which,  Ibr.tlie  sake  of  simplicity,  one  of  these  princi|)lcs  only, 
stearine  and  soda  dissolved  in  water,  is  taken  as  an  example,  will  clearly  illustrate  this  inter- 
esting reaction : — 

Stearine. 


Stearate  of  oxide  of  glycerylc  +  soda+water 
rstcarate  of  sod  i  +  hydrate  of  oxide  of  glyeeryle 

hard  soap.  glycerine. 


982 

In  the  same  way : — 


SOAP. 


Oleine. 


Oleate  of  oxide  of  glvceryle + soda  +  water 
=oleate  of  soda  +  hydrate  of  oxide  of  glyceryle 
V , '    C ^ ; 

hard  soap.  glycerine, 

and  so  on  all  the  immediate  principles  of  which  the  fat  or  oil  employed  is  composed,  split- 
ting, that  is  to  say,  separating  from  this  oxide  of  glyceryle  to  form  a  stearate,  oleate,  mar- 
garate,  palniitatc,  &c.,  of  soda  or  of  potash,  and  glycerine,  (hydrate  of  oxide  of  glyceryle.) 

Soaps  made  with  soda  are  hard ;  those  made  with  potash  are  soft ;  the  degree  of  hard- 
ness l)eing  so  much  greater  as  the  melting  point  of  the  fats  employed  in  their  manufacture 
is  higlier ;  hence  tiie  more  oleine  a  fatty  matter  contains,  the  softer  the  soap  made  with  it 
will  be,  and  vice  vend.  Tlie  softest  soap,  therefore,  would  be  that  made  altogether  with 
oleine  (oleic  acid)  and  potash  (oleate  of  potash);  the  hardest  would  be  that  made  with  stea- 
rine  and  soda,  (stearate  of  soda.) 

The  fats  or  oils  employed  for  the  manufacture  of  soaps,  are  tallow,  suet,  palm  oil,  cocoa- 
nut  oil,  kitchen  fat,  bone  grease,  horse  oil  or  fat,  lard,  butter,  train  oil,  seal  oil,  and  other 
tish  oil.-<,  rape  oil,  poppy  oil,  lin.seed  and  hcmpseed  oil,  olive  oil,  oil  of  almonds,  sesame,  and 
ground  nut  oil,  and  re.si>i.  This  last  sul)stance,  though  very  soluble  in  alkaline  menstrua, 
is  not,  however,  susceptible,  like  fiits,  of  being  transformed  into  an  acid,  and  will  not,  of 
course,  saponify  or  form  a  proper  soap  by  itself.  The  more  caustic  the  alkali  the  less  con- 
sistence has  the  lesinous  compound  which  is  made  with  it.  The  employ  of  caustic  alkalies, 
however,  is  not  necessary  with  it,  since  it  dissolves  readily  in  aqueous  solutions  of  carbon- 
ated alkalies ;  but  even  with  carbonate  of  soda  it  forms  only  a  viscid  mass,  owing  to  its  great 
affinity  for  water,  so  that  even  after  having  been  artificially  dried  in  an  oven,  and  thus  ren- 
dered to  a  great  extent  hard,  the  mass  deliquesces  again  spontaneously  by  exposure,  and 
returns  to  the  soft  state.  The  drying  oils,  such  as  those  of  linseed  and  poppy,  produce  the 
softest  soaps. 

We  said  that,  by  boiling  fats  or  oils  with  an  aqueous  solution  of  potash  or  of  soda,  a  so- 
lution of  soap  was  produced.  The  object  of  the  soap-maker  is  to  obtain  the  soap  thus  pro- 
duced in  a  solid  form,  which  is  done  by  boiling  the  soapy  mass  so  as  to  evajjorate  the  excess 
of  water  to  such  a  point  that  the  soap  may  separate  from  the  concentrated  liquor  and  float 
oil  tiie  surface  thereof  in  a  melted  state,  or  by  an  admixture  of  common  salt,  soap  being  in- 
soluble in  lyes  of  a  certain  strength  of  degree  of  concentration,  and  in  solutions  of  common 
salts  of  a  certain  strength,  the  glycerine  remaining,  of  course,  in  solution  in  the  liquor  be- 
low the  separated  soap.  Such  is  the  theory  of  soap-making;  but  the  viodus  operandi  fol- 
lowed by  practical  soap-makers  will  be  described  piesently. 

On  the  Continent  olive  oil,  mixed  with  about  one-fifth  of  rape  oil,  is  principally  used  in 
making  hard  soap.  This  addition  of  rape  oil  is  always  lesorted  to,  because  olive  oil  alone 
yields  a  soap  so  h  ird  and  so  compact  that  it  dissolves  only  with  difficulty  and  slowly  in  water, 
which  is  not  the  case  with  rape  oil  and  other  oils  of  a  similar  nature,  that  is  to  say,  with  oils 
which  become  thick  and  viscid  by  exposure,  and  which  on  that  account  are  called  drying 
oils ;  experience  having  taught  that  the  oils  which  dry  the  soonest  by  exposure,  yield  with 
soda  a  .softer  soap  than  that  made  with  oils  which,  like  olive  oil,  remain  limpid  for  a  long 
period  under  the  influence  of  the  air.  The  admixture  of  rape  oil  has,  therefore,  the  efFect 
of  modifying  the  degree  of  hardness  of  the  soap,  and,  therefore,  of  promoting  its  solubility. 
In  England  tallow  is  used  instead  of  olive  oil,  the  soap  resulting  from  its  treatment  with 
soda  is  known  under  the  name  of  curd  sonp^  and  is  remarkable  for  the  extreme  difficulty 
with  which  it  dissolves  in  water.  The  small  white  cubic,  waxy,  stubborn  masses,  which  un- 
til a  few  years  were  generally  met  with  on  the  washing-stand  of  bedrooms  in  hotels,  and 
which  for  an  indefinite  period  pa.>vsed  on  from  traveller  to  traveller,  each  in  turn  unsuccess- 
fully attempting,  by  various  devices  and  cunning  immersions  in  water,  to  coax  it  into  a  lath- 
er, is  curd  son f>.  Rape  or  linseed  oil,  added  in  eeitain  proportions  to  tallow,  would  modify 
this  extreme  hardness  and  difficult  solubility;  but  it  is  now  the  general  practice  to  qualify 
the  tallow  with  cocoa-nut  oil — an  oil,  which,  converted  into  soap,  has  the  property  of  absorb- 
ing incriMlible  quantities  of  water,  so  that  the  soap  into  the  manufacture  of  which  it  has  en- 
tered lathers  immeiliately.  Cocoa-nut  oil,  however,  acfjuires  l>y  saponification  a  most  disa- 
gvoealjle  odor,  (due  to  the  formation  of  caprylic  acid,)  which  it  imparts  to  all  the  soaps  in 
the  manufacture  of  which  it  enters — an  odor  which  peisists  in  sjjite  of  any  perfume  which 
may  be  added  to  ma-k  it. 

The  admixture  of  one-fourth  or  one-fifth  of  resin  with  tallow,  in  the  process  of  saponifi- 
cation, mollifies  also  the  hardness  and  considerably  increases  the  solubility  of  curd  soap,  and 
this,  in  fact,  constitutes  the  best  yellow  sonp. 

I  .«aid  that  soap  was  more  or  less  hard  in  proportion  as  the  melting  point  of  the  fats  em- 
ploved  in  its  manufacture  was  higlier  or  lower.  There  are  certain  fatty  substances,  techni- 
cally called  weak  goods,  such  as  kitchen  fat,  bone  fat,  horse  oil,  &c.,  which  could  hardly  be 


SOAP. 


98-6 


used  alone,  still  less  with  resin,  the  soap  which  they  yield  being  too  soft,  and  melting  or 
dissolving  awaj-  too  rapidly  in  the  washing-tub.  This  led  me  to  think,  that  if  a  means  could 
be  devised  of  artificially  hardening  soap,  a  larger  class  of  oleaginous  and  fatty  substances 
could  be  rendered  available,  at  any  rate  to  a  greater  extent  than  they  hitherto  had  been, 
and  that,  by  thus  extending  the  resources  of  the  soap  boiler,  he  should  be  enabled  to  pro- 
duce a  good  and  useful  soap  from  the  cheapest  materials,  and  thus  convert  soaps  of  little 
commercial  value  into  useful  and  economical  products. 

In  making  experiments  with  this  view,  I  found  that  the  introduction  of  a  small  quantity 
of  melted  crystals  or  sulphate  of  soda  into  the  soap  answered  the  purpose  admirably,  and 
that  the  salt,  in  recrystallizing,  imparted  to  the  soap,  which  otherwise  would  have  been  soft, 
a  desirable  hardness,  and  prevented  its  being  wa.sted  in  the  tub.  The  use  of  sulphate  of 
soda  acts,  therefore,  inversely,  like  the  addition  of  rape  oil,  or  linseed  oil,  or  of  resin  to  tal- 
low, in  the  manufacture  of  soap.  This  process,  which  I  patented  in  1841,  has  been,  since 
the  removal  of  the  uuties  on  soap,  extensively  employed  by  soap-makers,  and  continues  to 
be  highly  approved  of  by  the  public. 

3fantif act  lire  of  mottled  soap. — Soda  which  contains  sulphurets  is  preferred  for  making 
the  mottled  or  marbled  soap,  whereas  the  desulphuretted  soda  makes  the  best  white  curd 
soap.  Mottling  is  usually  given  in  the  London  soap-works,  by  introducing  into  the  nearly 
finished  soap  in  the  pan  a  certain  quantity  of  the  strong  lye  of  crude  soda,  through  the  rose 
spout  of  a  watering-can.  The  dense  sulphuretted  liquor,  in  descending  through  the  pasty 
mass,  causes  the  marbled  appearance.  In  France  a  small  quantity  of  solution  of  sulphate 
of  iron  is  added  during  the  boiling  of  the  soap,  or  rather  with  the  first  service  of  the  lyes. 
The  alkali  seizes  the  acid  of  the  sulphate,  and  sets  the  protoxide  of  iron  free  to  mingle  with 
the  paste,  to  absorb  more  or  less  oxygen,  and  to  produce  thereby  a  variety  of  tints.  A  por- 
tion of  oxide  combines  also  with  the  stearine  to  form  a  metallic  soap.  When  the  oxide 
passes  into  the-  red  state,  it  gives  the  tint  called  manteaii  Isabellc.  As  soon  as  the  inottlcr 
has  broken  the  paste,  and  made  it  pervious  in  all  directions,  he  ceases  to  push  his  rake  from 
right  to  left,  but  only  plunges  it  perpendicularly  till  he  reaches  the  lye ;  then  he  raises  it 
suddenly  in  a  vertical  line,  making  it  act  like  the  stroke  of  a  piston  in  a  pump,  whereby  he 
lifts  some  of  the  lye,  and  spreads  it  over  the  surface  of  the  paste.  In  its  subsequent  descent 
through  the  numerous  fissures  and  channels  on  its  way  to  the  bottom  of  the  pan,  the  color- 
ed lye  impregnates  the  soapy  particles  in  various  forms  and  degrees,  whence  a  varied  mar- 
bling results.  , 

The  best  and  most  esteemed  soap  on  the  Continent  is  that  known  mider  the  name  of 
Marseilles  soap,  and  it  ditfers  from  the  English  mottled  soap  by  a  diflerent  disposition  of  the 
mottling,  which  in  that  soap  is  granitic  instead  of  being  streaky.  It  has  also  an  agreeable 
odor,  somewhat  resembling  that  of  the  violet,  whereas  the  English  mottled  soap,  generally 
made  of  very  coarse  kitchen  and  bone  fat,  has  an  odor  which  reminds  one  of  the  fat  em- 
ployed. The  best  English  mottled  soap  in  which  tallow  is  employed,  has  no  unpleasant 
smell,  and  if  bleached  palm  oil  has  been  used  it  acquires  an  agreeable  odor,  analogous  to 
that  of  the  Marseilles  soap,  which  is  made  of  olive  oil  alone,  or  mixed  with  rape  or  other 
grain  or  seed  oil,  which,  however,  seldom  exceeds  10  per  cent. ;  for  otherwise  it  would  not 
have  the  due  proportion  of  blue  to  the  white,  which  is  characteristic  of  soap  made  of  genuine 
olive  oil,  the  motthng  becoming  more  closely  granular  when  an  undue  proportion  of  grain 
has  been  used,  a  sign  of  depreciation  which  the  dealers  are  perfectly  well  acciuainted  with, 
and  of  which  they  at  once  avail  themselves,  to  compel  the  maker  to  reduce  his  price. 

Pelouze  and  Fremy,  in  their  Traite  de  chimie  ffenerale,  give  the  following  reliable  obser- 
vations : — 

"  The  best  olive  oil  for  the  use  of  the  soap-maker  is  Provence  oil ;  that  of  Aix  comes  next ; 
it  is  cheaper,  but  the  same  weight  of  it  yields  less  soap  than  the  other,  and  the  latter  has  then 
a  slight  lemon  yellow  tinge.  The  oil  from  Calabre  contains  less  margarine,  and  yields  a 
softer  soap. 

"Two  kinds  of  soda  ash  are  used  in  Marseilles,  the  soft  soda  (sonde  douce)  and  the  salt- 
ed soda  (sonde  salec),  which  contain  a  large  quantity  of  common  salt. 

"  To  prepare  the  lye,  the  soft  soda  previously  reduced  into  small  lumps  is  mixed  with 
12  per  cent,  of  slaked  lime,  and  shovelled  up  into  tanks  of  masonry  of  about  2  cul)ic  yards' 
capacity,  called  barquieux,  and  the  exhaustion  of  the  mass  with  water  gives  lyes  of  various 
degrees  of  strength. 

"The  lye  marking  12°  is  used  for  the  first  treatment,  or  cmputarjc  of  the  oil,  which  is 
then  submitted  to  a  second  and  third  treatment  with  a  lye  marking  15'  or  20",  the  object 
of  which  is  to  close  the  grains  of  the  emulsive  m  iss  in  process  of  saponification,  (scrrcr  Vem- 
pdtar/e.)  The  operation  requires  about  twenty-four  hours.  During  all  the  time  of  that  op- 
eration a  workman  is  constantly  agitating  the  boiling  mixture  of  tlie  oil  and  lye  by  means 
of  a  long  rake  or  c.utch,  called  rdble.  The  enifxllage  is  generally  practised  in  large  conical 
tanks  of  ma.sonry  terminated  at  bottom  by  a  copper  pan,  and  capable  of  containing  12  or  lo 
tons  of  made  soap,  and  the  operation  proceeds  so  much  tiie  more  rapidly,  as  the  soda  ho 
employed  contains  less  common  salt ;  wherefore  soft  soda  lye  (sonde  douce)  must  be  iiued  at 
I'le  beginning,  as  we  said. 


984  SOAP. 

"  The  next  operation  is  that  called  relargarjc,  the  object  of  which  is  to  separate  the  larpe 
quantity  of  water  which  has  been  used  to  facilitate  the  empdtage.  This  separation  of  the 
water,  or  rdargage,  is  effected  by  means  of  salted  soda,  (that  is  to  say,  of  soda  a.'^h,  contain- 
ing a  good  deal  of  common  salt),  of  which  as  much  is  dissolved  in  water  as  will  make  a  lye 
marking  20°  or  25°.  This  salted  lye  is  then  gradually  poured  by  a  workman  on  the  surface 
t;f  the  saponifying  goods  in  the  copper,  while  another  workman  is  diffusing  it  in  the  mass 
by  etirrijig  the  whole  with  a  rake  or  crutch. 

"  The  immediate  effect  of  the  salt  thus  added  is  to  separate  from  the  soapy  mass  the 
water  in  which  it  was  dissolved,  and  which  gave  it  a  homogeneous  and  syrupy  appearance, 
and  to  coagulate  it,  the  soap  being  thereby  curded  or  coagulated,  and  converted  into  a  mul- 
titude of  granules  floating  among  the  excess  of  water  in  which  they  were  dissolved,  and 
which  the  salt  has  separated.  The  whole  being  then  left  at  rest  for  two  or  three  hours,  in 
order  to  give  the  grains  of  soap  time  to  rise  and  agglomerate  at  the  surface,  a  workman 
proceeds  to  the  epinage,  an  operation  which  consists  in  withdrawing  the  hquid  portion  by 
removing  a  wooden  plug  placed  at  the  lower  part  of  the  boiler." 

In  this  country  the  epinage  is  generally  performed  by  means  of  an  iron  pump  plunging 
through  the  soap  down  to  the  pan  at  the  bottom  of  the  copper. 

This  xpent  h/e,  in  well-conducted  factories,  retains  but  little  alkali,  and  is  generally 
thrown  away;  but  as  it  contains  a  rather  large  quantity  of  salt,  which,  in  PVance,  is  an  ex- 
pensive article,  it  might  be,  and  is  sometimes,  kept  and  used  for  preparing  fresh  lyes. 

After  the  first  epinage,  the  soap  is  treated  twice  again  with  salt  lye,  followed  of  course 
by  two  (-phiages ;  but  as  the  salt  lye  used  in  these  two  operations  is  not  exhausted,  it  is  al- 
ways kept  for  preparing  fresh  lyes. 

The  cleansing,  that  is  to  say,  the  removing  of  the  soap  into  the  frames,  takes  place  on 
the  third  day,  at  which  time  the  operation  called  madrage  is  performed.  J'or  that  purpose 
a  plank  is  thrown  across  the  boiler  or  copper,  and  two  or  three  men  standing  on  it,  and 
therefore  over  the  soapy  mass  in  the  copper,  proceed  to  stir  it  up  for  two  or  three  hours, 
by  means  of  long  crutches,  which  they  alternately  move  up  and  down  through  it,  the  object 
being  to  keep  the  grains  of  soap  well  diffused  through  the  liquid,  weak  lyes  marking  only 
8°  or  10",  or  ordinary  water,  as  the  case  may  be,  being  sprinkled  from  time  to  time  into  the 
mas.s,  until  the  grains  of  soap  have  reabsorbed  a  sufficient  quantity  of  water  and  have  swol- 
len to  such  a  size  as  to  have  a  specitie  gravity  very  little  greater  than  that  of  the  liquid 
among  which  they  float  about.  A  skilful  workman  knows  by  the  appearance  of  the  soap 
grains  whether  he  should  use  alkaline  lyes  or  simply  water,  and  this  is  indeed  a  most  im- 
portant point  in  the  manufacture  of  Marseilles  soap,  for  upon  it  the  success  of  the  operation 
depends  in  a  commercial  point  of  view,  that  is  to  say,  all  things  being  equal  in  other  re- 
spects, a  profit  or  loss  on  the  batch  of  soap  made  will  ensue.  In  effect,  if  too  much  water 
has  been  added  the  soap  will  lose  either  the  whole,  or  too  great  a  portion  of  its  mottling ; 
that  is  to  say,  the  result  will  be  either  a  dingy  white  curd,  or  a  soap  in  which  the  white  por- 
tions will  predominate  to  too  great  an  extent  over  the  blue  streaks,  a  circumstance  which 
so  far  deteriorates  the  market  value,  the  buyer  shrewdly  suspecting  then  that  he  would  pay 
for  water  the  price  of  soap.  If,  on  the  contrary,  a  sufficient  quantity  of  water  has  not  been 
added,  the  soap  grains  remaining  hard  and  dry,  will  form  more  or  less  friable,  thereby  caus- 
in"-  also  a  deterioration  of  price,  the  buyer  knowing  that  such  soap,  by  crumbling  into  small 
pieces  every  time  he  has  to  cut  it  with  his  knife  in  selling  it  to  his  customers,  will  consider- 
ably reduce  his  profit,  or  perhaps  even  entail  a  positive  loss  to  him. 

In  the  best  conditions,  that  is  to  say,  by  employing  the  best  Gallipoii  oil  for  the  purpose 
of  producing  Marseilles  soap  of  fir.st  quality,  100  cwt.  of  olive  oil  yield  175  cwt.  of  mottled 
soap ;  liy  using  mixtures  of^  olive  and  rape  or  other  seed  oils,  the  yield  of  soap  is  reduced 
to  170,  or  even  less;  in  either  case  the  yield  is  reduced  by  5  or  G  per  cent.,  when  old  or 
fermented  is  employed  instead  of  new  good  oil. 

The  manufacturing  expenses  are  calculated  at  Marseilles  at  the  rate  of  17f.  25c.  (nearly 
13s.  and  lOj.)  per  ioo  kilogrammes  of  fatty  matter  employed,  wliich  require  72  kilo- 
grammes of  soda  for  their  saponification. 

Mottled  soap  has  a  marbled,  or  streaky  appearance,  that  is  to  say,  it  has  veins  of  a  blu- 
ish color,  and  resembling  granite  in  their  disposition  or  arrangement.  The  size  and  num- 
ber of  these  veins  or  speckles,  and  the  proportion  which  they  bear  to  the  white  ground  of 
the  soap,  depend  not  only  on  the  more  or  less  rapid  cooling  of  the  soap  after  it  has  been 
cleansed,  that  is,  transferred  from  the  copper  to  the  frame,  but  also  on  the  quality  and  kind 
of  the  fat,  grease,  or  oil  employed,  and  on  the  manner  in  which  it  has  been  treated  in  the 
copper.  A  soap  which  has  not  been  sufficiently  boiled  at  the  last  stage  of  the  manufacture 
is  always  tender.  The  blue  or  slate-color  of  the  streaks  or  veins  of  mottled  soap  is  due  to 
the  presence  of  an  alumino-ferruginous  soap  interposed  in  the  mass,  and  frequently  also 
to  that  of  sulphurct  of  iron,  which  is  produced  by  the  reaction  of  the  alkaline  sulphurcts 
contained  in  the  soda  lye  upon  the  iron,  derived  from  the  soda  ash  itself,  and  from  the  iron 
pans  and  other  utensils  employed  in  the  manufacture,  or  which  is  even  purposely  intro- 
duced in  the  state  of  solution  of  proiosulphate  of  iron.     This  introduction,  however,  is  never 


SOAP.  985 

resorted  to,  I  believe,  in  this  country.  The  veins  or  streaks  disappear  from  the  surface  to 
the  centre  by  keeping,  because  the  iron  becomes  gradually  peroxidized.  A  well-manul'ac- 
tured  mottled  soap  cannot  contain  more  tlian  33,  34,  or  at  most  36  per  cent,  of  water, 
whereas  genuine  curd  soap  contains  45,  and  yellow  soap  at  least  52  per  cent,  of  water,  and 
sametimes  considerably  more  than  that.  It  is  evident,  in  edect,  tliat  the  mottling  being  due 
to  the  presence  of  sulphuret  of  iron  held  in  the  state  jiaitly  of  deuiisolution  and  of  suspen- 
sion, the  addition  of  water  would  cause  the  coloring  substances  to  subside,  and  a  white,  mii- 
colored,  or  fitted  soap  would  be  tlie  result.  This  addition  of  water,  technically  called  ///('/w.f/, 
is  made  when  tlie  object  of  tlic  manufacturer  is  to  ol)tain  a  inueolored  soap,  whetlier  it  be 
curd  or  yeUow  soap.  Afti^r  fi (tin ff,  the  soap  contains,  therefore,  an  additional  ciuantity  of 
water,  which  sometimes  amounts  to  55  per  cent. :  the  interest  of  tlie  consumer  would,  tliere- 
fore,  cle  irly  be  to  buy  mottled  soap  in  preference  to  yellow  or  white  soap ;  the  mottling, 
when  not  artificially  imitated,  being  a  sure  criterion  of  genuineness ;  for  the  adihtion  of 
water,  or  of  any  other  substance,  would,  as  was  just  said,  infallibly  destroy  the  mottling. 
To  yellow  or  curd  soap,  on  the  contrary,  incredible  quantities  of  water  may  Ije  added.  I 
have  known  five  pails  of  water  (15  gallons)  added  to  a  frame  (10  cwt.)  of  already  _/?//?(/ soap, 
so  that  tlie  soap,  by  this  treatment,  contained  upwaids  of  60  per  cent,  of  water,  to  which 
common  s  ilt  liaJ  previously  been  added.  The  proportion  of  water  in  fitted  soap  has  also 
been  augmented,  in  some  instances,  by  boiling  the  soap  in  high-pressure  boilers  before  c^ea;i.?- 
i7iff.  As  cocoa-nut  oil  has  the  property  of  absorbing  one-third  more  water,  v/hen  made 
into  soap,  than  any  other  material,  its  consumption  by  the  soap-maker  has,  within  the  last 
fifteen  or  twenty  years,  augmented  to  an  extraordinary  extent ;  and,  moreover,  the  patent 
taken  in  1857  by  Messrs.  Blake  and  Maxwell,  of  Liverpool,  for  the  invention  of  Mr.  Kottula, 
which  we  shall  describe  presently,  has,  I  believe,  increased  the  demand  for  that  species  of 
oil  in  a  notable  degree.  We  said  that  the  mottling,  inasmuch  as  it  was  indicative  of  genu- 
ineness, was  the  more  economical  soap  to  buy ;  unfortunately  mottled  soap  has  the  draw- 
back of  not  being  so  readily  soluble  as  yellow  .soap,  and  the  goods  washed  with  it  are  more 
difficult  to  rinse;  but  the  process  patented  by  Messrs.  Blake  and  Maxwell  enabling  the  man- 
ufacturer to  manufacture  with  coa-nut  od  a  soap  to  which  the  mottling  is  artificially  impart- 
ed, by  means  of  ultramarine,  black  or  brown  oxide  of  manganese,  in  such  a  perfect  manner 
as  almost  to  defy  detection,  mottling  has  thus  ceased  to  be  a  safe  outward  sign  of  genuineness, 
as  far  as  regards  the  article  which  it  pretends  to  represent.  That  description  of  soap,  how- 
ever, has  specific  qualities;  it  is  almost  perfectly  neutral,  and  it  will  not  bear  more  than 
a  definite  proportion  of  water ;  so  that,  although  it  contains  more  of  that  rupiid  than  ordi- 
nary mottled  soap, — more  than  a  certain  fixed  quantity  cannot  be  forced  into  it;  so  that  it 
also  forms  a  standard  soap,  like  the  ordinary  mottled,  although  that  standard  is  different 
from,  and  inferior  to,  the  latter.  The  process  in  question  ia  briefly  as  follows: — Take  80 
cwt.  of  palm  oil,  made  into  soap  in  the  usual  way,  with  two  changes  of  lye,  grained  with 
strong  lye,  or  lye  in  the  usual  manner,  but  so  that  the  lye  leaves  the  curd  perfectly  free  ; 
pump  the  spent  lye  away,  and  add  32  cwt.  of  cocoa-nut  oil,  GO  cwt.  of  lye,  at  20"  of 
Beaume's  areometer,  and  then  gradually  14  cwt.  of  lye,  at  14°  Beaume.  Boil  until  the 
whole  mass  is  well  saponified.  Put  now  from  6  to  7  lbs.  of  ultramarine  in  water,  or  weak 
lye,  stir  the  whole  well,  and  pour  it  into  the  soap  through  the  rose  of  a  watering  pot ;  boil 
the  whole  tor  aljout  half  an  hour,  or  an  hour,  and  cleanse  it  in  the  ordinary  wooden  iVames, 
or  in  iron  frames  surrounded  by  matting,  or  other  covering,  so  that  the  soap  may  not  cool 
too  rapidly:  the  above  proportions  will  yield  212  cwt.  of  soap,  with  a  beautiful  blue  mottle. 

Determination  of  water  and  iin/niritics. — Besides  water,  soap  is  often  adulterated  by 
gelatine,  forming  a  soap  sometimes  called  "  bone  soap,"  which  is  made  by  adding  to  the 
soap  a  solution  of  disintegrated  bones,  sinews,  skins,  hoofs,  sprats,  and  other  cheap  fish  in 
strong  caustic  soda;  also  by  dextrine,  potato  starch,  pumice  stone,  silica,  plaster,  clay,  salt, 
chalk,  carbonate  of  soda,  &c.,  and  by  fats  of  another  or  inferior  kind  than  those  from  which 
they  are  represented  to  have  been  made.  These  impurities  or  superadded  materials  and 
their  amount  may  be  ascertained  in  the  following  manner : 

Estimation  of  the  (juimtity  of  water: — Take  about  1,000  grains  of  th(>  soap  under  cxam- 
inition,  cut  into  small  and  thin  slices,  not  only  from  the  outside,  which  is  always  drier,  but 
from  the  interior  of  the  sam[)le,  so  that  the  whole  may  represent  a  fair  average ;  mix  the 
mass  well  together,  and  of  this  weigh  accurately  100  grains;  place  it  in  an  oven  heated  to 
a  temperature  of  212°  Fahr.,  until  it  is  quite  dry,  weighing  it  occasionally  until  no  loss  or 
diminution  of  weight  is  observed,  the  ditference  between  the  original  and  the  last  weight, 
the  loss,  indicates,  of  course,  the  proportion  of  water.  The  loss  of  water  in  mottled  soap 
and  in  soft  soap  should  not  be  more  than  30  to  35  per  cent. ;  in  white  or  yellow  soap  from 
3G  to  at  most  50  per  cent. 

If  the  soap  is  sulphated,  the  amount  of  sulphate  craployed  may  bo  determined  by  taking 
200  grains  of  the  sample,  dissolving  it  in  a  cap.sule  with  boiling  water,  adding  to  the  boiling 
solution  as  much  hydrochloric  acid  as  is  necessary  to  render  the  li(|uid  strongly  acid,  aiul 
therefore  to  decompose  the  soap  entirely,  throwing  the  whole  in  a  filter  jircviously  wetted 
with  water,  adding  to  the  filtrate  an  excess  of  chloride  of  barium,  washing  thoroughly  the 


986  SOAP. 

■white  precipitate  so  produced,  igniting  and  weighing  it ;  every  grain  of  sulphate  of  barytes 
thus  obtained  represents  r467  grain  of  crystallized  sulphate  of  soda. 

If  the  soap  contains  clay,  chalk,  silica,  dextrine,  fecula,  pumice  stone,  ochre,  plaster, 
salt,  gelatine,  &c.,  dissolve  100  grains  of  the  sr^pected  soap  in  alcohol,  with  the  help  of  a 
gentle  heat;  the  alcohol  will  dissolve  the  soap  and  leave  all  these  impurities  in  an  insoluble 
etate.  Good  mottled  soap  should  not  leave  more  than  1  per  cent,  of  insoluble  matter,  and 
■white  or  yellow  soap  still  less.  All  soap  to  which  earthy  or  siliceous  matter  has  been  added 
is  opaque  instead  of  transparent  at  the  edges,  as  is  the  case  with  all  genuine  or  fitted  and 
sulphated  soap.     The  drier  the  soap,  the  more  transparent  it  is. 

Bone  soap,  or  glue  soap,  is  recognized  by  its  unpleasant  odor  of  glue  and  its  dark  color, 
its  want  of  transparency  at  the  edges ;  that  made  with  the  fat  of  the  intestines  of  animals 
has  a  disgusting  odor  oifteces. 

When  uncombined  silica  has  been  added  to  soap,  its  presence  may  be  readily  detected 
by  dissolving  the  suspected  soap  in  alcohol,  as  before,  when  the  silica  will  be  left  in  an  in- 
soluble state  ;  but  if  the  silica  is  in  the  state  of  silicate  of  soda  or  of  potash,  it  is  necessary 
to  proceed  as  follows: — dissolve  a  given  weight  of  the  suspected  soap  in  boiling  water,  anil 
decompose  it  by  the  gradual  addition  of  moderately  dilute  hydrochloric  acid,  until  the  liquor 
is  strongly  acid ;  boil  the  whole  for  one  or  two  minutes  longer  and  allow  it  to  cool  in  order 
that  the  fatty  acids  having  separated  and  become  hard,  may  be  removed.  Evaporate  the 
acid  liquor  to  perfect  dryness,  and  the  perfectly  dry  mass  treated  with  boiling  water  will 
leave  an  insoluble  residue  which  may  be  identified  as  silica  by  its  grittiuess,  which  is  recog- 
nized by  rubbing  it  in  the  capsule  with  a  glass  rod.  This  white  residue  should  then  be  col- 
lected on  a  filter,  washed,  dried,  ignited,  and  weighed. 

The  proportion  of  alkali  (potash  or  soda)  may  be  easily  determined  by  an  alkalimetrical 
assay  as  follows : — 

Take  100  grains  of  the  soap  under  examination,  and  dissolve  them  in  about  2,000  grains 
of  boiling  water ;  should  any  insoluble  matter  be  left,  decant  carefully  the  superincumbent 
solution  and  test  it  with  dilute  sulphuric  acid  of  the  proper  strength,  exactly  as  described 
in  the  article  on  alkalimetry. 

The  proportion  of  alkali  contained  in  soap  may  also  be  ascertained  by  incinerating  a 
given  weight  of  soap  in  an  iron  or  platinum  spoon,  crucible,  or  capsule,  treating  the  residue 
with  water,  filtering  and  submitting  the  filtrate  to  an  alkalimetrical  assay.  This  method, 
however,  cannot  be  resorted  to  when  the  soap  contains  sulphates  of  alkalies,  because  the 
ignition  would  convert  such  salts,  or  a  portion  thereof,  into  carbonates  of  alkali,  ■which  by 
saturating  a  portion  of  the  test-sulphuric  acid  would  give  an  inaccurate  result. 

The  proportion  of  oil  or  fat  in  soap  is  ascertained  by  adding  100  grains  of  pure  white 
wax  free  from  water  to  the  soap  solution,  after  supersaturation  with  an  acid,  and  heating 
the  whole  until  the  wax  has  become  perfectly  liquid,  and  has  become  perfectly  incorporated 
with  the  oil  or  fat  which  has  separated  by  the  treatment  with  an  acid.  The  •«hole  is  then 
allowed  to  cool,  and  the  waxy  cake  obtained  is  removed,  heated  in  a  weighed  crucible  or 
capsule  to  a  temperature  of  about  220"^  Fahr.  in  order  to  expel  all  the  water,  after  which 
the  whole  is  weighed ;  the  increase  above  100  grains  (the  original  weight  of  the  wax)  indi- 
cates, of  course,  the  quantity  of  grease,  fat,  or  oil  contained  in  the  soap.  This  addition  of 
wax  is  necessary  only  when  the  fatty  matter  of  the  soap  is  too  liquid  to  solidify  well  in  cool- 
ing. Good  soap  ordinarily  contains  from  6  to  8  per  cent,  of  soda;  from  60  to  70  per  cent, 
of  fatty  acids  and  rosin,  and  from  30  to  35  per  cent,  of  water. 

The  nature  of  the  fat  of  which  a  given  sample  of  soap  has  been  made  is  more  difficult  to 
detect;  yet,  by  saturating  the  aqueous  solution  of  the  mass  under  examination  with  an  acid, 
collecting  the  fatty  acids  which  then  float  on  the  surface,  and  observing  their  point  of  fusion, 
the  operator  at  any  rate  will  be  thus  enabled  to  ascertain  whether  the  soap  under  examina- 
tion is  identical  with  the  sample  from  which  it  may  have  been  purchased,  and  whether  it 
was  made  from  tallow,  or  from  oil,  &c. 

When  the  fatty  acids  which  have  been  isolated  and  collected  by  decomposing  the  soap 
with  an  acid,  as  already  described,  are  heated  in  a  small  capsule  the  odor  evolved  is  often 
characteristic,  or  at  least  generally  gives  a  clue  to  the  nature  of  the  fats  or  oils  from  which 
the  soap  has  been  made.  This  odor  is  often  sufficiently  perceptible  at  the  moment  when 
the  aqueous  solution  of  the  soap  is  decomposed  by  the  acid  poured  in.  Cocoa-nut  oil  can 
always  be  detected  when  in  proportions  at  all  available  to  the  soap-maker  by  tasting  the 
poap,  that  is  to  say,  by  leaving  the  tongue  in  contact  with  the  soap  for  a  few  moments,  when 
a  peculiar,  very  disagreeable  and  bitter  flavor  will  become  more  or  less  perceptible. 

Properly  made  soap  should  dissolve  completely  in  pure  water;  if  a  film  or  oily  matter 
is  seen  to  float  on  the  surface,  it  is  a  proof  that  all  the  fat  is  not  saponified.  Another  test 
ia  that  the  fatty  or  oily  acid  separated  by  decomposing  the  aqueous  solution  of  the  soap  by 
hydrochloric  acid,  should  be  entireli/  soluble  in  alcohol. 

Soft  soaps,  as  we  said,  are  combinations  of  fats  or  oils  with  potash,  or  rather  are  solu- 
tions of  a  potash  soap,  in  a  lye  of  potash,  and  they  therefore  always  contain  a  great  excess 
of  alkali,  and  a  more  or  less  considerable  proportion  of  water;  they  contain  also  a  certain 


SODA,  CARBONATE  OF. 


mi 


quantity  of  chloridea,  of  sulphates,  and  all  the  glycerine  which  the  saponifying  process  haa 
set  free.  Soft  soap  in  this  country  is  generally  used  for  fulling,  and  for  cleansing  and  scour- 
ing woollen  stuffs.  In  Belgium,  Holland,  and  Germany  it  is  used  also  for  washing  linen, 
which  thereby  acquires  an  almost  intolerable  odor  of  fish  oil,  which  no  amount  of  perfume 
can  mask,  fish  oil  being  generally  employed  in  the  manufacture  of  that  description  of  soap. 
The  most  esteemed  soft  soap,  however,  is  that  made  from  hempseed  oil,  which  imparts  to 
the  soap  a  greenish  color,  but  this  much-prized  color  is  generally  or  very  often  artificially 
given  to  the  soap  made  of  other  oil,  which  soap  has  a  yellow  color,  by  means  of  a  little 
indigo  finely  pulverized  and  previously  boiled  for  some  time  in  water.  For  further  particu- 
lars on  the  manufacture  of  soap,  see  vol.  ii. 

SODA,  CARBONATE  OF  (Kohlcusaurcs'tiatron,  Germ.)  Manufacture. — The  manufac- 
ture divides  itself  into  three  branches : — 1.  The  conversion  of  sea  salt,  or  chloride  of  sodium, 
into  sulphate  of  soda.  2.  The  decomposition  of  this  sulphate  into  crude  soda,  called  black 
balls  by  the  workmen.  3.  The  purification  of  these  balls,  either  into  a  dry  white  soda  ash  ov 
into  crystals. 

Preparation  of  Sulphate  of  Soda. — The  decomposition  of  the  common  salt  {chloride  of 
sodium)  by  sulphuric  acid  is  effected  in  furnaces,  of  vi\nc\ijig.  608  is  a  drawing,  taken  from  Dr. 


?^ 


Miller's  Elements  of  Chemistry,  a,  the  smaller  of  the  two  compartments  which  compose 
the  furnace,  is  of  cast  iron ;  into  this  [t.he  decomposei')  from  five  to  six  hundred  weight  of 
common  salt  are  introduced,  and  an  equal  weight  of  sulphuric  acid,  of  specific  gravity  1"6, 
is  gradually  mixed  with  it;  a  gentle  heat  being  applied  to  the  outside,  enormous  volumes  of 
hydrochloric  acid  gas  are  disengaged,  and  pass  off  by  the  flue  d  to  the  condensing  towers  e 
and  F;  these  towers  are  filled  with  fragments  of  broken  coke,  or  stone,  over  which  a  continu- 
ous stream  of  water  is  caused  to  trickle  slowly  from  h  h.  A  steady  current  of  air  is  drawn 
through  the  furna(?e  and  condensing  towers,  )>y  connecting  the  first  tower  with  the  second, 
as  represented  at  cf,  and  the  second  tower  with  the  main  chimney,  k,  of  the  works.  In  the 
first  bed  of  the  furnace,  about  half  of  the  common  salt  is  decomposed,  leaving  a  mixture 
of  bisulphate  of  soda  and  common  salt,  which  requires  a  greater  heat  for  the  expulsion  of 
this  latter  portion  of  hydrochloric  acid ;  for  this  purpose  it  is  pushed  through  a  door  into  the 
roaster^  or  .second  division,  b,  of  the  furnace. 

The.  'Wflction  in  the  first  bed  of  the  furnace  is  represented  as  follows : — 

2NaCl         +         2HS0^  =  NaSO*  IISO«     +    HCl  4-         NaCI 


Common  salt. 


Sulphuric  acid. 


Common  salt. 


By  the  higher  temperature  obtained  in  this  second  part  of  the  furnace,  the  bisulphate  of 
soda  reacts  on  the  undecomposed  chloride  of  sodium,  yielding  neutral  sulphate  of  soda  and 
a  fresh  quantity  of  hydrochloric  acid. 

NaSO\  USD'         +         NaCl        =         2(NaS0^)         -f         IICl 


Bisulphate  of  soda. 


Common  salt. 


Sulpliato  of 
soda. 


Hydrochloric 
acid. 


The  hydrochloric  acid  gas,  as  it  is  liberated  from  n,  passes  off  through  the  flue,  </,  and  is 
carried  on  to  the  condensing  toweis.  Heat  is  applied  to  the  outside  of  the  roaster,  b;  the 
stnoke,  o,  circulating  in  separate  flues  around  the  chamber,  in  the  direction  indicated  by  the 
arrows,  but  never  coming  into  contact  with  the  salt  cake  in  b. 

By  the  kindness  of  J.  L.  Bell,  Esq.,  of  Newcastle-upon-T)me,  wc  are  enabled  to  give  the 


988 


SODA,  CARBONATE  OF. 


009 


process  used  at  present  in  that  district.  It  difTers  but  little  from  that  above  described,  with 
the  exception  that  in  the  decomposition  of  the  mixture  of  bisulphute  of  soda  and  common 
salt,  in  the  second  jjortion  of  the  furnace,  the  smoke  and  products  of  combustion  from  the 
tire  are  allowed  to  come  in  contact  with  the  mateiials,  and  the  hydrochloric  acid  which  is 
then  given  olf  is  carried  to  condensing  towers  tilled  with  bricks  over  which  water  is  contin- 
ually slowly  running,  and  the  dilute  hydrochloric  acid  thus  obtained  is  used  for  the  libera- 
tion of  carbonic  acid  in  the  manufacture  of  bicarbonate  of  soda.  The  first  part  of  the 
furnace  is  a  circular  metal  pan,  and  the  hydrochloric  acid  from  this  being  unmixed  with 
smoke,  &c.,  is  condensed  apart  fidin  the  other. 

The  next  step  in  the  manufacture  is  the  decomposition  of  the  sulpliate  of  soda  into 

sulphide  of  sodium,  and  its  subsequent  con- 
veision  into  carbonate  of  soda.  This  is 
effected  in  the  following  miinner: — The  dry 
sulphate  of  soda,  obtained  by  the  process 
above  desciibed,  is  mixed  with  small  coal 
and  chalk,  or  limestone,  in  about  the  follow- 
ing pioportions;  sulphate  of  soda  3  parts, 
chalk  31  parts,  and  coal  2  parts.  It  is 
necessary  that  these  mateiials  should  be 
first  separately  ground,  and  sifted  into  a 
tolerably  fine  powder,  and  then  carefully 
mixed,  as  a  great  deal  depends  on  the  atten- 
tion to  these  points.  The  mixture  is  then 
subjected  to  heat  in  a  reverberatory  fur- 
nace, X^.s.  €.09,  610,  611, 

In  the  section  Jtr/.  610,  there  are  two 
hearths  in  one  fuinace,  the  one  elevated 
aljove  the  level  of  tlie  other  by  the  thick- 
ness of  a  brick,  or  about  three  inches,  a 
is  the  preparatory  shelf,  wheie  the  mixture 
to  be  decomposed  is  first  laid  in  order  to  be 
thoioughly  heated,  so  that,  when  transferred 
to  the  lower  or  decon. posing  hearth  b,  it 
n:ay  not  essentially  chill  it,  and  throw  back 
the  operation,  c  is  the  fire  bridge,  and  d 
is  the  giate.  In  the  horizontal  section,  or 
ground  plan,^r/.  611,  we  see  an  opening 
in  the  fiont  cones[.cnding  to  each  hearth. 
This  is  a  door,  as  shown  in  the  side  view  or 
elevation  of  the  fuinace,  jiV/.  e(»9;  and  each 
door  is  shut  by  an  iion  squaie  fiame  filled 
with  "SI  fire  tile  or  bricks,  and  suspended  by  a  chain  over  a  pulley  fixed  in  any  convenient 
place.  The  workman,  on  pushing  up  the  door  lightly,  n:akes  it  rise,  because  there  is  a  coun- 
ter weight  at  the  other  end  of  each  chain,  which  balances  the  weight  of  the  fi  ame  and  bricks. 
In  the  ground  plan,  only  one  smoke  flue  is  shown  ;  and  this  constiuc<«on  is  preferred  by 
many  manufacturers;  but  others  choose  to  have  two  flues,  one  fiom  each  shoulder,  as  at  a, 
b;  which  two  flues  afterward  unite  in  one  vertical  d.in.ncy,  fiom  25  to  40  feet  high; 
because  the  draught  of  a  soda  furnace  must  be  ^cry  sluuj).  Having  sufficiently  explained 
the  construction  of  this  improved  furnace,  we  shall  now  piocctd  to  desciibe  the  mode  of 
making  soda  with  it. 

The  quantity  of  this  mixture  required  for  a  charge  depends,  of  course,  on  the  size  of  the 
furnace.  This  charge  must  be  shovelled  in  upon  the  hearth  a,  or  shelf  of  prepaiation,  {fcf. 
610;)  and  whenever  it  has  become  hot,  (the  lurnace  having  been  previously  bi ought  to 
bright  ignition,)  it  is  to  be  transferred  to  the  decomposing  hearth  or  laboratory  b,  by  an  iion 
tool,  shaped  exactly  like  an  oar,  called  the  spreader.  This  tool  las  the  flattened  part  fiom 
2  to  3  feet  hjiig,  and  the  round  part,  for  laying  hold  of  and  working  by,  from  6  to  7  feet 
long.  Two  other  tools  are  used  ;  one  a  rake,  bent  down  with  a  garden  hoe  at  the  end  ;  and 
another,  a  small  shovel,  consisting  of  a  long  ircn  rod  terminated  like  a  piece  of  iron  plate, 
about  ti  inches  long,  4  broad,  sharpened  and  tijiped  with  steel,  for  cleaning  the  bottom  of 
the  hearth  from  adhering  cakes  or  crusts.  AVhenever  the  charge  is  shoved  by  the  .sliding 
motion  of  the  oar  down  upon  the  working  hearth,  a  fresh  charge  should  be  thrown  into  the 
preparation  shelf,  an<l  evenly  spread  over  the  surface. 

The  hot  and  partially  c.irlionized  charge  being  also  evenly  spread  tipon  the  hearth  B,  is  to 
be  left  untouched  for  aliout  ten  minutes,  during  which  time  it  becomes  ignited,  and  begins  to 
fuse  upon  the  surface.  A  view  may  be  taken  of  it  through  a  peep-hole  in  the  door,  which 
should  be  .shut  immediately,  in  order  to  prevent  the  reduction  of  the  temperature.  When 
the  mass  is  seen  to  lie  in  a  state  of  incijiient  fusion,  the  workman  takes  the  oar  and  turns  it 
over  breadth  ijy  breadth  in   regular  layers,  till   ho  haa  reverseil  the  position   of  the  whole 


SODA,  CAEBOXATE  OF. 


989 


mass,  placing  on  the  surface  the  particles  which  were  formerly  in  contact  with  the  hearth. 
Having  done  this  he  immediately  shuts  the  door,  and  lets  the  whole  get  another  decompos- 
ing heat.  After  fire.or  six  minutes,  jets  of  flame  begin  to  issue  from  various  parts  of  the 
pasty-consistenced  mass.  Now  is  the  time  to  incorporate  the  materials  together,  turning 
and  spreading  by  the  oar,  gathering  them  together  by  the  rake,  and  then  distributing  them 
on  the  reverse  part  of  the  hearth ;  that  is,  the  oar  should  transfer  to  the  part  next  the  fire- 
bridge the  portion  of  the  mass  lying  next  the  shelf,  and  vice  versa.  The  dexterous  manage- 
ment of  this  transposition  characterizes  a  good  soda  furnacer.  A  little  practice  and  instruc- 
tion will  render  this  operation  easy  to  a  robust,  clever  workman.  After  tiiis  transposition, 
incorporation,  and  spreading,  the  door  may  be  shut  again  for  a  few  minutes,  to  raise  the  heat 
for  the  finishing  off.  Lastly,  the  rake  must  be  dexterously  employed  to  mix,  shift,  spread, 
and  incorporate.  The  jets  called  candles,  are  very  numerous,  and  bright  at  first ;  and  when- 
ever they  begin  to  fiide,  the  mass  must  be  raked  out  into  cast  iron  moulds,  placed  under  the 
door  of  the  laboratory  to  receive  the  ignited  paste. 

One  batch  being  thus  worked  off,  the  other,  which  has  lain  undisturbed  on  the  shelf,  is  to  be 
shoved  down  from  a  to  b,  and  spread  equally  upon  it,  in  order  to  be  treated  as  above 
described.     A  third  batch  is  then  to  be  placed  on  the  shelf. 

The  product  thus  obtained  is  called  "  black  balls,"  which  of  course  vary  in  their  compo- 
sition. The  following  is  the  composition,  according  to  Eichardson,  of  the  Newcastle  "  black 
balls  "  from  the  balling  furnaces : — ■ 

Carbonate  of  soda  9"89,  hydrate  of  soda  25'64,  sidphide  of  calchan  35"57,  carbonate  of 
lime  15.67,  sulphate  of  soda  3'64,  chloride  of  sodium  O'CO,  sulphide  of  iron  I "22,  silicate  of 
magyiesia  0"88,  carbon  4'28,  sand  0-44,  and  water  2-17. 

The  principal  changes  which  take  place  in  this  process  may  be  represented  by  the  follow- 
ing equations : — 

NaSO*         +         4C         =         NaS         -+-        4C0 


then — 


NaS 


+ 


Carbon. 


CaCO'  = 


Sulphide  of 
sodium. 

NaCO' 


+ 


CaS 


Chalk. 


In  the  first  place,  the  sulphate  of  soda  is  deoxidized  by  the  coal,  with  the  formation  of 
sulphide  of  sodium  and  carbonic  oxide,  which  latter  takes  fire  and  forms  the  handles  above 
mentioned ;  in  the  next  place,  the  sulphide  of  sodium  and  carbonate  of  lime  (chalk)  decom- 
pose each  other,  forming  carbonate  of  soda  and  sulphide  of  calcium ;  and  from  the  fact  of 
some  of  the  chalk  being  converted  into  caustic  hme  by  the  heat  of  the  furnace,  there  is  also 
formed  by  it  some  caustic  soda  ;  the  sulphide  of  calcium  itself  is  only  sparingly  soluble  in 
water,  but  is  rendered  still  less  so  by  the  excess  of  lime  which  is  present,  forming  with  it  an 
oxysulphide,  which  is  much  less  soluble  than  the  sulphide  of  calcium  alone. 

This  black  ball,  or  ball  alkali,  is  then  treated  with  warm  water  to  extract  the  soluble 
matters.  This  is  effected  in  the  districts  of  Newcastle-on-Tyne  in  vessels  8  or  10  feet 
square  and  5  or  6  feet  deep,  furnished  with  false  bottoms ;  the  first  waters  are  strong  enough 
for  boiling  down,  for  getting  yellow  salt,  as  it  is  termed ;  the  after  washings,  which  are 
weaker,  are  used  for  fresh  quantities  of  "  ball  alkali."  Care  must  be  taken  not  to  use  the 
water  too  hot,  as  the  oxysulphide  of  calcium  would  be  decomposed,  and  the  liquor  thus  take 
up  much  sulphide  of  calcium. 

An  apparatus  used  in  some  places  for  lixiviating  the  black  ball  is  shown  in  the  accom- 
panying drawing, /?^.  G12,  taken  from  Dr.  Miller's  "Elements  of  Chemistry."  Its  object  is 
to  extract  the  largest  quantity  of  soluble  matter  with  the  smallest  quantity  of  water.  The 
black  ball  is  placed  in  perforated  sheet-iron  vessels,  n  n,  which  can  be  raised  or  lowered 
into  outer  lixiviating  vessels,  also  made  of  iron,  by  means  of  the  cords  and  pulleys  i,  K. 
Wheifa  charge  is  received  from  the  furnace,  it  is  introduced  into  the  lowest  vessel  g,  where 
it  is  submitted  to  the  dissolving  action  of  a  liquid  already  highly  charged  with  alkali  from 
digestion  upon  the  black  ash  contained  in  the  tanks  above  it;  after  a  certain  time  this  charge 
is  raised  by  the  rope  from  g  into  the  tank  f,  where  it  is  submitted  to  a  weaker  li(iuid,  and  so 
on,  successively.  The  alkali  at  each  stage  becomes  more  completely  exhausted,  ami  the  res- 
idue is  successively  submitted  to  the  action  of  weaker  lye,  till  at  lengtli,  in  a,  it  is  acted  on  by 
water  only,  supplied  from  the  cistern  l.  When  fresh  water  is  admitted  from  m,  to  the  top 
of  the  vessel  a,  as  it  is  specifically  lighter  than  the  saline  solution,  it  lies  upon  its  surface, 
and  gradually  displaces  the  solution  from  a,  through  the  bent  tube,  whilst  the  water  takes 
its  place ;  the  liquid  thus  displaced  from  it,  acts  in  like  manner  upon  that  contained  in  b  ;  and 
this  displacement  proceeds  simultaneously  through  each  successive  tier  of  the  arrangement, 
until  the  concentrated  lye  flows  off  from  g,  and  is  transferred  to  the  evaporating  pans.  The 
residue  which  remains  after  this  treatment  contains  nearly  all  the  sulphur  present  in  the  ball 
alkali,  in  the  form  of  oxysulphide  of  calcium,  together  with  the  other  insoluble  portions, 


990 


SODA,  CAEBONATE  OF. 

612 


and  is  of  no  value  ;  it  accumulates  to  an  immense  extent  in  large  soda  works,  and  is  thus  a 
source  of  annoyance.  Many  trials  have  been  made  to  obtain  the  sulphur  coritained  in  it, 
and  to  use.  it  for  the  reproduction  of  sulphuric  acid,  but  without  much  success  hitherto. 

The  solution  obtained  by  thus  lixiviating  the  ball  soda,  contains  principally  carbonate  of 
soda  and  hydrate  of  soda,  as  well  as  some  sulphide  and  chloride  of  sodium,  and  a  little  sul- 
phate of  soda.  It  is  allowed  to  settle ;  then  the  clear  liquor  is  drawn  ofl'  into  evaporating 
vessels.     These  may  be  of  two  kinds.     The  surface-evaporating  furnace,  shown  in  Ji(/.  613, 

is  a  very  admirable  invention  for  econo- 
"■'^  mizing  vessels,  time,  and  fuel.  The  grate, 

A,  and  fire-place,  are  separated  from  the 
evaporating  laboratory  d,  bj'  a  double 
fire  bridge  b,  c,  having  an  interstitial 
space  in  the  middle,  to  arrest  the  com- 
munication of  a  melting  or  igniting  heat 
toward  the  lead-lined  cistern  D.  This 
cistern  may  be  8,  10,  or  20  feet  long, 
according  to  the  magnitude  of  the  soda- 
work,  and  4  feet  or  more  wide.  Its  depth 
should  be  about  4  feet.  It  consists  of 
sheet  lead,  of  about  6  pounds  weight  to 
the  square  foot,  and  it  is  lined  with  one  layer  of  bricks,  set  in  Koman  or  hydraulic  cement, 
both  along  the  bottom  and  up  the  sides  and  ends.  The  lead  comes  up  to  the  top  of  c,  and 
the  liquor,  or  lye,  may  be  filled  in  to  nearly  that  height.  Things  being  thus  arranged,  a  fire 
is  kindled  upon  the  grate  A  ;  the  flame  and  hot  air  sweep  along  the  surface  of  the  liquor, 
raise  its  temperature  there  rapidly  to  the  boiling  point,  and  carry  off  the  watery  parts  in 
vapor  up  the  chimney  e,  which  should  be  15  or  20  feet  high,  to  command  a  good  draught. 
But,  indeed,  it  will  be  most  economical  to  build  one  high,  capacious  chimney  stalk,  as  is  now 
done  at  Glasgow,  Manchester,  and  Newcastle,  and  to  lead  the  flues  of  the  several  furnaces 
above  described  into  it.  In  this  evaporating  furnace  the  heavier  and  stronger  lye  goes  to 
the  bottom,  as  well  as  the  impurities,  where  they  remain  undisturbed.  Whenever  the  liquor 
has  attained  to  the  density  of  1-3,  or  thereby,  it  is  pumped  up  into  evaporating  cast-iron 
pans,  of  a  flattened,  somewhat  hemispherical  shape,  and  evaporated  to  dryne.'--s  while  being 
diligently  i^tirred  with  an  iron  ralce  and  iron  scrajier. 

This  alkali  gets  partially  carbonated  by  the  above  surface-evaporating  furnace,  and  is  an 
excellent  article. 

When  ])urc  carbonate  is  wanted,  that  dry  mass  must  be  mixed  with  its  own  bulk  of 
ground  coal,  sawdust,  or  charcoal,  and  thrown  into  a  reverberatory  furnace.  Here  it  must 
be  exposed  to  a  heat  not  exceeding  650"  or  700°  F. ;  that  is,  a  little  above  the  melting  heat  of 
lead ;  the  only  object  being  to  volatilize  the  sulphur  present  in  the  mass,  and  carbonate  the 
alkali.  Now,  it  has  been  found,  that  if  the  heat  be  raised  to  distinct  redness,  the  sulphur 
will  not  go  off,  but  will  continue  in  intimate  union  with  the  soda.  This  process  is  called 
calking,  and  the  furnace  is  called  a  calkcr  furnace.  It  may  be  6  or  8  feet  long,  and  4  or  5 
feet  broad  in  tlic  hearth,  and  requires  only  one  door  in  its  side,  with  a  hanging  iron  frame 
filled  wiih  a  flre-tile  or  bricks  as  above  described. 


SODA,  CAEBONATE  OF. 


991 


This  carbonating  process  may  be  performed  upon  several  cwts.  of  the  impure  soda  mixed 
with  sawdust,  at  a  time.  It  takes  three  or  four  hours  to  finish  the  desulphuration  ;  and  it 
must  be  carefully  turned  over  by  the  oar  and  the  rake,  in  order  to  burn  the  coal  into  car- 
bonic acid,  and  to  present  the  carbonic  acid  to  the  particles  of  caustic  soda  diffused  through 
the  mass,  so  that  it  may  combine  with  them. 

When  the  blue  flames  ceases,  and  the  saline  matters  become  white,  in  the  midst  of  the  coaly 
matter,  the  batch  may  be  considered  as  completed.  It  is  raked  out,  and,  when  cooled,  lixi- 
viated in  great  iron  cisterns  with  false  bottoms,  covered  with  mats.  The  watery  solution 
bLMug  drawn  off  clear  by  a  plug-hole,  is  evapprated  cither  to  dryness,  in  hemispherical  cast- 
iron  pans,  as  above  described,  or  only  to  such  a  strength  that  it  shows  a  pellicle  upon  its 
surface,  when  it  may  be  run  off  into  crystallizing  cisterns  of  cast  iron,  or  lead-lined  wooden 
cisterns.     The  above  dry  carbonate  is  the  best  article  for  the  glass  manufacture. 

Instead  of  this  last  process  of  roasting  with  sawdust,  Gossage  decomposes  the  sulphide 
of  sodium  present  in  the  lye  obtained  from  the  ball  soda,  by  means  of  the  hydrated  oxide  of 
so.no  metal,  as  of  lead,  thus  forming  sulphide  of  lead  and  hydrate  of  soda;  this  is  then  con- 
verted into  carbonate  by  passing  a  stream  of  carbonic  acid  through  it.  The  precipitated 
sulphide  of  lead  is  decomposed  by  hydrochloric  acid,  thus  generating  sulphuretted  hydrogen, 
which  is  burnf  and  converted  into  sulphuric  acid;  the  lead  is  then  converted  again  into 
hydrated  oxide  by  means  of  lime.  This  process  saves  the  trouble,  time,  and  fuel  used  in 
evaporating  to  dryness  twice,  as  in  the  ordinary  process. 

Various  attempts  have  been  made  to  obtain  processes  which  shall  supersede  the  process 
above  described,  of  manufacturing  carbonate  of  soda  from  common  salt,  but  none  appear 
to  have  been  successful  to  any  great  extent.     We  shall  here  mention  some  of  them. 

1.  Sulphate  of  iron,  being  a  cheap  article,  has  been  heated  with  common  salt  instead  of 
using  sulphuric  acid ;  sulphate  of  soda  is  formed,  and  the  chloride  of  iron,  being  volatile, 
passes  away.  The  latter  part  of  the  process  was  of  course  similar  to  that  above  described. 
2.  By  roasting  iron  or  copper  pyrites  directly  with  chloride  of  sodium,  sulphate  of  soda  has 
been  obtained,  and  it  has  been  found  possible  by  this  means  also  to  extract  the  metal  from 
ores  of  copper  or  tin  with  advantage,  which  are  otherwise  too  poor  to  work.  Mr.  Tilghman 
effects  the  decomposition  of  chloride  of  sodium  by  steam  at  a  high  temperature,  in  the  pres- 
ence of  alumina.  Precipitated  alumina  is  made  up  into  balls  with  chloride  of  sodium,  and 
exposed  Jo  a  current  of  steam  in  a  reverberatory  furnace  strongly  heated.  Hydrochloiic 
acid  is  expelled  and  the  alumina  unites  with  the  soda. 

NaCl       +       Al-0^     +    no     =     NaO,APO^       +  HCl 


Chloride  of  sodium.  Alumina.  Steam.  Aluminate  of  soda.  Hydrochloric  acid. 
When  cold,  this  compound  of  alumina  and  soda  is  decomposed  by  a  current  of  carbonic 
acid,  and  the  carbonate  of  soda  is  dissolved,  and  thus  separated  from  the  alumina,  which 
may  be  again  used.  Another  process  is  that  patented  by  AIM.  Schlcpsing  and  RoUand, 
which  is  as  follows  :  — They  dissolve  the  chloride  of  sodium  in  water,  and  then  pass  ammonia 
into  it,  and  afterward  carbonic  acid ;  bicarbonate  of  ammonia  is  first  produced,  and  then 
doul)le  decomposition  takes  place  ;  chloride  of  ammonium  is  formed,  and  the  more  sparing- 
ly-soluble bicarbonate  of  soda  is  precipitated  in  crystalline  grains ;  it  is  then  separated  from 
the  liquid  and  pressed,  to  free  it  as  much  as  possible  from  the  chloride. 

NaCl  +         Nn'CO^HCO^     =     NaColIICO^        +  Nirci 


Chloride  of  sodium.  Bicarbonate  of  ammonia.  Bicarbonate  of  soda.  Chloride  of  aiinnonium. 
This  liicarbonate  of  soda  is  converted  into  the  monocarbonate  by  heat,  and  the  carbonic 
acid  thus  evolved  is  used  again  ;  the  solution,  from  which  the  bicarbonate  has  separated,  is 
lioiled  to  drive  off  any  ammonia  that  it  may  contain,  as  carbonate  of  ammonia,  which  is 
collected  ;  the  solution  is  then  boiled  with  lime,  which  liberates  the  ammonia  from  the 
chloride  of  ammonium,  and  thus  little  loss  is  sustained,  the  same  ammonia  serving  continu- 
ally, within  certain  limits,  because,  of  course,  some  ammonia  escapes  and  is  unavoidal)le  lost. 

There  are  three  carbonates  of  soda  commonly  known,  viz.,  monocarbonate,  scuquicar- 
boiinte,  and  bicarbonate. 

Monocarbonate.  NaCO'+lOHO.  This  is  the  salt  which  is  obtained  in  the  ordinary 
soda  manufaettu-e.  In  the  crystalline  state,  it  generally  contains  ten  cf|uivalents  of  water 
.)f  crystallization,  sixty-three  per  cent.,  but  has  been  obtained  with  only  eight,  five,  and 
oven  one  equivalent  of  water.  It  effloresces  in  a  dry  atmosphere,  at  the  same  time  absorb- 
ing carbonic  acid.  It  is  very  solulile  in  water,  requiring  only  twice  its  weight  of  water  at 
iyf  for  solution,  and  even  melts  in  its  own  water  of  crystallization  when  heated,  and  event- 
ually by  increase  of  temperature  )>ccomes  anhydrous.  It  is  generally  found  in  commerce 
i  1  large  crystals,  which  l)elong  to  the  oblique  prismatic  system.  It  is  strongly  alkaline,  and 
acts  on  the  skin,  dissolving  the  outside  cuticle.  It  is  largely  used  in  the  manufacture  of 
soap,  gla.ss,  &c.,  and  is  generally  too  well  known  to  recpiire  much  description. 

The  .soda  trade  made  great  progress  in  1850,  as  compared  with  the  two  preceding 
years.     In  1857,  1,538,988  cwts.  were  exported,  of  the  value  of  £'7(;0,741  ;  and  in   ]ii:>'\ 


992 


SODA,  NITRATE  OF. 


1,018,289  cwts.,  of  the  value  of  £813,'72Y;  whilst  last  year  the  quantity  was  2,027,609, 
cwts.,  and  the  value  £1,024,283. 

Scsquicarbonate.  2NaUU^,HC0'.  This  salt  is  frequently  found  native,  and  is  described 
under  Natuon,  vol.  ii.,  (which  see.) 

Bicarbonate.  NaCO^,HCO'.  This  salt  is  found  in  some  mineral  waters,  as  those  of 
Carlsbad  and  Seltzer ;  and  is  obtained  from  the  waters  of  Vichy  in  large  quantities. 

It  is  prepared  by  saturating  the  monocarbonate  with  carbonic  acid,  for  which  purpose 
several  methods  are  employed. 

1.  By  passing  carbonic  acid  into  a  solution  of  the  moiiocavbonatc. — A  cold  saturated 
solution  of  the  monocarbonate  of  soda  is  made,  and  carbonic  acid,  obtained  by  the  action 
of  hydrochloric  acid  on  marble  or  challi,  is  passed  into  it ;  the  bicarbonate  forms  and  pre- 
cipitates to  a  great  extent,  and  is  then  collected,  pressed  to  remove  as  much  of  the  adhering 
liquid  as  possible.  A  fresh  portion  of  the  monocarbonate  is  dissolved  in  the  mother  liquor, 
and  the  passage  of  carljonic  acid  through  it  repeated.  By  this  method  a  pure  bicarbonate 
is  obtained,  but  the  process  is  costly. 

2.  By  exposing  solid  inonocarbonate  of  soda  to  an  atmosphere  of  carbonic  acid  gas. — 
This  is  known  as  Smith's  process.  The  crystals  of  the  monocarbonate  are  placed  on  shelves, 
slightly  inclined  to  allow  the  water  to  run  off,  in  a  large  bo.\,  containing  a  perforated  false 
bottom ;  carbonic  acid  is  passed  into  this  box  under  pressure,  which  latter  is  scarcely  neces- 
sary, since  the  monocarbonate  so  rapidly  absorbs  the  carbonic  acid.  When  the  gas  ceases 
to  be  al)Sorbed,  the  salt  is  taken  out  and  dried  by  a  gentle  heat. 

The  crystals  are  found  to  have  lost  their  water  of  crystiillization,  and  to  have  become 
opaque  and  porous,  and  a  bicarbonate,  still,  however,  retaining  their  original  shape.  These 
are  giound  between  stones  like  flour,  care  being  taken  to  avoid  the  evolution  of  much  heat. 

This  is  the  most  economical  process,  but  does  not  yield  a  perfectly  pure  product,  yet, 
nevertheless,  quite  pure  enough  for  ordinary  purposes,  the  impurities  contained  in  it  being  a 
little  chloride  of  sodium  and  sulphate  of  soda,  found  in  the  original  monocarbonate  from 
which  it  was  made,  and  even  these  are  to  a  great  extent  dissolved  and  carried  off  by  the 
water  of  crystallization  as  it  escapes. 

3.  Its  formation  by  the  action  of  bicarbonate  of  ammonia  has  been  already  described. 
Bicarbonate  of  soda  crystallizes  in  rectangular  four-sided  prisms,  which  require  about 

ten  parts  of  cold  water  to  dissolve  them,  and  if  the  solution  be  boiled,  it  loses  carbonic 
acid,  becoming  first  sesquicarbonate,  and  ultimately  monocarbonate.  As  usuallyTnet  with 
in  commerce,  this  salt  is  a  white  powder.  Its  taste  is  slightly  alkaline.  It  is  largely  used 
in  medicine,  for  making  seidlitz  powders,  &c. ;  but  the  salt  generally  found  in  the  shops  is 
only  a  sesquicarbonate,  or  a  mixture  of  bicarbonate  and  sesquicarbonate. — II.  K.  B. 

"soda,  NITIIATE  OF.  (NaO,NOl)  ^yn.  cubic  vitre ;  QhWa,  saltpetre.  {Nitrate  de 
sonde,  Fr. ;  Wiirfclsdlpetcr,  Germ.)  This  important  salt  is  found  native  in  immense  quanti- 
ties in  Chili  and  Peru.  It  is,  in  some  parts,  found  in  beds  of  several  feet  in  thickness.  As 
found  in  nature  it  is  tolerably  pure,  the  principal  impurities  being  chlorine,  sulphuric  acid, 
and  lime. 

It  is  evident  that  nitrate  of  soda  can  be  formed  artificially  by  saturating  nitric  acid  with 
soda  or  its  carbonate,  and  evaporating  the  solution  until  the  salt  crystallizes. 

In  analyzing  a  sample  of  the  salt,  it  should  be  dissolved  in  boiling  distilled  water;  any 
insoluble  matters  are  to  be  removed  by  the  filter,  and,  after  being  washed  and  dried,  may 
be  weighed.  To  the  clear  filtrate  acidulated  with  pure  nitric  acid,  nitrate  of  silver  is  to  be 
added  ;  the  precipitate  of  chloride  of  silver,  when  weighed  with  proper  precautions,  will  en- 
able the  amount  of  chloride  of  sodium  to  be  calculated.  For  this  purpose  we  say  :  as  one 
equivalent  of  chloride'of  silver  is  to  one  equivalent  of  chloride  of  sodium,  so  is  the  quanti- 
ty of  cliloride  of  silver  obtained  to  the  quantity  of  chloride  of  sodium  in  the  specimen 
taken.  In  another  portion  of  the  salt,  the  solution  being  prepared  as  before,  the  sulphuric 
acid  may  be  determined  by  precipitation  with  chloride  of  barium ;  and,  in  a  third,  the  lime 
and  magnesia  are  to  be  determined  by  precipitation,  the  first  with  oxalate  of  ammonia,  and 
the  latter  in  the  filtrate  from  the  oxalate  of  lime,  by  means  of  phosphate  of  soda  and  am- 
monia. The  water  may  be  determined  by  drying  a  known  weight  of  the  salt  in  the  water 
bath  until  it  ceases  to  diminish  in  weight.  A  good  sample  of  nitrate  of  soda  should  not 
contain  more  than  two  per  cent,  of  chloride  of  sodium. 

Solubility  of  Nitrate  of  Soda  in  Water. 

One  part  uf  the  salt  dissolves  in — 
1'58  at  a  temperature  of  21 '2°  Fahr. 
1-25  "  "  320 

1-36  "  "  66-0 

1-12  "  "  82-4 

0-77  "  "         116-6 

0-46  "  "         246-2 

The  above  table  is  not  perfectly  satisfactory,  and  tlie  solubility  of  nitrate  of  soda  in 
water  at  different  temperatures  requires  reinvestigation. 


SOLDERS.  993 

Nitrate  of  soda  is  not  applicable  for  the  preparation  of  gunpowder  or  fireworks,  partly 
in  consequence  of  its  tendency  to  attract  moisture  from  the  air,  and  partly  owing  to  the 
fact  that  mixtures  made  in  imitation  of  gunpowder,  but  having  nitrate  of  soda  in  place  of 
nitrate  of  potash,  explode  far  less  powerfully  than  gunpowder  itself. 

Nitrate  of  soda  is  extensively  and  economically  employed  as  a  source  of  nitric  acid.  It 
is  also  used  for  the  purpose  of  being  converted  by  double  decomposition  with  chloride  of 
potassium  into  nitrate  of  potash.     It  is  employed  in  great  quantities  as  a  manure. 

The  term  cubic  nitre  applied  to  this  salt  is  incorrect ;  the  crystals,  it  is  true,  appear 
cubic  at  a  rough  gl.ince,  but  they  are  in  fact,  rhombohedra,  of  which  the  angles  are  not  very 
I'ar  removed  from  those  of  a  cube. — C.  G.  W. 

SODIUM.  (Na.)  This  metal  was  discovered  by  Sir  H.  Davy,  almost  immediately  after 
potassium,  and  by  the  same  means,  viz.,  by  exposing  a  piece  of  moistened  hydrate  of  soda 
to  the  action  of  a  powerful  voltaic  batteiy,  the  alkali  being  placed  between  a  pair  of  plati- 
num plates  connected  with  the  battery. 

By  this  process  only  very  small  quantities  could  be  obtained,  and  processes  have  since 
been  devised  which  provide  it  in  almost  any  quantity,  and  since  the  demand  for  sodium  in 
the  maimfacture  of  aluminium  by  Wohler's  process,  principally  by  the  exertions  of  M.  St. 
Clair  Deville,  the  cost  of  it  has  been  considerably  diminished.  The  process  now  adopted  is 
the  same  as  that  for  obtaining  potassium ;  an  intimate  mixture  of  carbonate  of  soda  and 
charcoal  is  made  by  igniting  in  a  covered  crucible  a  salt  of  soda  containing  an  organic  acid, 
as  the  acetate  of  soda,  &c.,  or  by  melting  ordinary  carbonate  of  soda  in  its  water  of  crystalli- 
zation and  mixing  with  it,  while  liquid,  finely  divided  charcoal,  and  evaporating  to  dryness ; 
tliis  mixture  is  mixed  with  some  lumps  of  charcoal  and  placed  in  a  retort,  which  is  generally 
made  of  malleable  iron  ;  but,  owing  to  the  difficulty  of  getting  these  sufficiently  large,  earth- 
enware or  fireclay  retorts  have  been  used  with  success,  and  sometimes  these  are  lined  with 
or  contain  a  trough  of  malleable  iron.  These  retorts  are  so  placed  in  a  furnace  that  they 
are  uniformly  kept  at  a  heat  approaching  to  whiteness. 

Mr.  Beatson  {Pharmaceutical  Journal^  vol.  xv.  p.  226)  made  an  improvement  in  the 
process  by  which  it  can  be  carried  on  continuously  for  a  week  or  fortnight.  If  the  pro- 
portion of  charcoal  and  soda  be  well  regulated,  the  retort  becomes  nearly  empty  at  the  end 
of  the  process.  In  Mr.  Beatson's  process,  as  soon  as  one  charge  is  worked  oft"  the  receiver 
is  removpd,  and  a  fresh  charge  is  introduced  through  the  same  tube  as  serves  to  convey  the 
sodium  to  the  receiver,  by  means  of  a  semicircular  scoop,  so  that  the  retort  is  kept  at  a 
constant  temperature,  and  hence  little  loss  of  time.  The  receiver  contains  rock-naphtha, 
and  is  surrounded  by  cold  water.  The  manuf\icture  of  sodium,  when  properly  conducted, 
is  much  easier  and  more  certain  than  that  of  potassium ;  one  advantage  is,  that  the  sodium 
does  not  unite  with  carbonic  oxide  to  form  the  explosive  compound,  and  the  conducting 
tube  is  not  so  likely  to  be  choked.  The  sodium  which  comes  over  is,  however,  mixed  with 
some  impurities,  croconates,  &c. ;  and  in  order  to  separate  the  metal  from  these,  Mr.  Beat- 
son  melted  the  sodium  under  mineral  naphtha,  in  a  cylinder,  into  which  is  fitted  a  piston, 
worked  by  a  screw  or  hydraulic  press,  and  when  this  is  forced  down  the  metal  forms  in  a 
mass  above  it,  -while  the  impurities  remain  at  the  bottom  of  the  cylinder. 

The  principal  reaction  which  takes  place  in  the  retort,  is  the  reduction  of  the  soda  by 
the  charcoal,  which  is  thus  converted  into  carbonic  oxide,  which  escapes  through  an  aper- 
ture in  the  receiver  made  on  purpose. 

NaO     +     C     =     Na     -f     CO 

Soda.        Charcoal.     Sodium.    Carbonic  oxide. 

Sodium  is  a  silver-white  metal,  very  much  resembling  potassium  in  every  respect ;  it  is 
so  soft  at  ordinary  temperatures  that  it  may  be  easily  cut  with  a  knife  or  pressed  between 
the  finger  and  thumb ;  it  melts  at  194°  F.,  and  oxidizes  rapidly  in  the  air,  though  not  so 
rapidly  as  potassium.  Its  sp.  gr.  is  0"972.  When  placed  upon  the  surface  of  cold  water  it 
decomposes  it  with  violence,  but  does  not  ignite  the  hydrogen  which  is  liberated,  imless  the 
motion  of  the  sodium  be  restrained,  when  the  cooling  effect  is  much  less.  When  a  few 
drops  of  water  are  added  to  sodium  the  hydrogen  liberated  immediately  inflames,  and  such 
is  also  the  case  if  it  be  put  on  hot  water ;  when  burning  it  produces  a  yellow  fianie,  and 
yields  a  solution  of  soda.     The  equivalent  of  sodium  is  23. 

When  sodium  is  l)urnt  in  oxygen  gas  or  in  air,  two  different  oxides  are  produced,  viz.  the 
protoxide,  (NaO,)  and  another  whose  composition  is  uncertain,  perhaps  binoxide  (NaO'^)  or 
teroxide,  (NaOl)  These  oxides  also  very  much  resemble  the  corresponding  oxide  of  i)otas- 
sium.  The  princi[)al  use  of  sodium  is,  as  before  stated,  in  the  manufacture  of  aluminium, 
which  is  now  carried  on  to  a  considerable  extent.     See  Aluminiitm. — II.  K.  B. 

SOLDERS.  Alloys  which  are  employed  for  the  purpose  of  joining  together  metals  are 
so  called.  They  are  of  various  kinds,  l)eing  generally  distinguished  into  hard  and  soft. 
Upon  the  authority  of  IIoltza[)pfel,  the  following  receipts  for  solder  are  given,  and  these 
have  been  adopted,  because,  after  a  long  and  particular  intiuiry  in  the  workshops,  we  learn 
that  these  are  regarded  as  very  superior  to  any  others  recommended. 
Vol.  III.— 68 


994 


SPECULUM  METAL. 


Peioterers'  Solder,     (a)  2  Bismuth,  4  lead,  3  tin.     (b)  1  Bismuth,  1  lead,  2  tin. 

Soft  Spelter  Solder.     Equal  parts  of  copper  and  zinc. 

Coarse  Plumbers'  Solder,  (a)  1  tin,  3  lead,  melts  at  about  500  F.  (6)  2  tin,  1  lead, 
melts  at  about   360  F. 

Spelter  Solder.     1 2  oz.  of  zinc  to  1 6  oz.  of  copper. 

(For  brass  work  the  metals  are  generally  mixed  in  equal  proportions  as  above.  For 
copper  and  iron  the  last  given  are  usually  employed.) 

The  following  Table  of  solders  has  been  constructed  by  the  late  Mr.  Iloltzappfel,  from 
a  Table  of  a  much  more  extended  character,  published  by  Mons.  H.  Gaulthier  de  Claubry. 


Alloys  and  their  Melting  Heats. 

Fluxes. 

1 

2 
3 
4 

5* 
6 

7 
8 

9 
10 
11 
12 
13 
14 
15 
16 
17 
18 

1    Tin        25     Lead     -         558°  Fahr. 
1       '<          10         "       -         541 
1       '«           5          "       -         511 
1       "           3          "       -         482 
1       "           2         •'       -         441 

1  "            1           '       -         370 
H    "           1          "       -         334 

2  "            1          "       -         340 

3  "            1          "       -         356 

4  "            1          "       -         365 

5  "            1          "       -         378 

6  "            1          "       -         381 
4    Lead  4  Tin  1  Bismutli  320 
3      "      3     "     1         "         310 
2      "      2     "     1         "         292 

1  "       1     "     1          "         254 

2  "       1     "     2         "         236 

3  "       6     "     3          "         202 

A  Borax. 

B  Sal  ammoniac. 

C  Chloride  of  zinc. 

D  Common  resin. 

E  Venice  turpentine. 

F  Tallow. 

G  Gallipoli  oil 

Modes  of  Applyisg  Heat. 

a  Naked  fire. 

b  Hollow  furnace  or  muffle. 

c  Imnrersion  in  melted  solder. 

d  Melted  solder  poured  on. 

e  Heated  iron  not  tinned. 

/  Heated  copper  tool  tinned. 

g  Blowpipe  flame. 

h  Flame  alone,  generally  alcohol. 

i   Stream  of  heated  air. 

SPECULUM  METAL.  The  metal  employed  in  the  mirrors  of  reflecting  telescopes. 
The  Earl  of  Rosso,  who  has  been  eminently  successful  in  the  production  and  publishing 
of  large  specula,  says,  in  his  paper  published  in  the  IVan.tactions  of  the  Royal  Society, 
"Tin  and  copper,  the  materials  employed  by  Newton  in  the  first  reflecting  telescope,  are 
preferable  to  any  other  with  which  I  am  acquainted,  the  best  proportions  being  4  atoms  of 
copper  to  1  of  tin,  (Turner's  numbers;)  in  fact,  126-4  parts  of  copper  to  58'9  of  tin." 

Mr.  Rosse  remarks  tliat  when  the  alloy  for  speculum  metal  is  perfect,  it  should  be  white, 
glassy,  and  flaky.  Copper  in  excess  imparts  a  reddish  tinge,  and  when  tin  is  in  excess, 
the  fi-acture  is  granulated  and  less  white.  Mr.  Ross  pours  the  melted  tin  into  the  copper, 
when  it  is  at  the  lowest  temperature  at  which  a  mixture  by  stirring  can  be  effected  ;  then 
he  pours  the  metal  into  an  ingot,  and,  to  complete  the  combination,  rcmelts  it  in  the  most 
gradual  manner,  by  putting  tlie  metal  into  the  furnace  almost  as  soon  as  the  fire  is  lighted. 
Trial  is  made  of  a  small  portion  taken  from  the  pot  immediately  prior  to  pouring. 

SriRlT  OF  SALTS.     Hydrochloric  or  muriatic  acid. 

SPIRITS  OF  WINE.     Alcohol,  (which  see.) 

SPONGE.  {Eponge.,  Fr. ;  Schwavvn,  Germ.)  For  a  long  time  it  was  a  disputed  point 
whether  the  sponge  of  commerce  belonged  to  the  animal  or  the  vegetable  kingdom.  Of 
late  years  the  evidence  has  appeared  to  be  conclusive  as  to  its  animal  nature. 

The  sponge  consists  of  a  soft  gelatinous  mass,  mostly  supported  by  an  internal  skeleton 
composed  of  reticularly  anastomosing  horny  fibres,  in  or  among  which  are  usually  imbed- 
ded siliceous  or  calcareous  spicula.  Sponges  are  rtfostly  marine — two  or  three  species  only 
being  found  in  fresh  water.  They  are  fixed  by  a  kind  of  root,  by  which  they  hold  firmly 
any  surface  upon  which  they  once  fix  themselves.  Sponges  may  be  propagated  by  division, 
but  more  usually  by  gcmmules,  which  detach  themselves  from  the  parent  body,  and  float 
about  until  they  find  a  fitting  resting-place,  where  they  fix  themselves  and  grow.  The 
s[)()nges  of  commerce  are  ot)tained  from  the  Mediterranean — Smyrna  being  the  principal 
mart.  They  are  collected  by  divers,  many  of  whom  have  been  trained  to  the  work  from  their 
infancy.     S[)onges  are  treated  with  muriatic  (hydrochloric)  acid  to  remove  the  lime. 

SPRUCE  BEER  is  prepared  as  follows: — Essence  of  spruce,  half  a  pint;  pimento  and 
ginger  bruised,  of  each  4  ounces ;  hops,  from  4  to  5  ounces ;  water,  3  gallons.  Boil  for  ten 
minutes,  then  strain  and  add  1 1  gallons  of  warm  water,  a  pint  of  yeast,  and  6  pints  of  mo- 
lasses.    Mix,  and  allow  the  mixture  to  ferment  for  twenty  hours. 

SPRUCE,  ESSENCE  OV,  is  prepared  by  boiling  the  young  tops  of  the  Abies  nigra,  or 
black  spruce,  in  water,  and  concentrating  the  decoction  by  evaporation. 

*  No.  5  is  the  Phimherfs'  sealed  solder,  which  is  as.saycd  and  then  stamped  by  an  officer  of  the 
Plumber's  Coiii[iany. 


STEAM.  995 

ST  ANNATE  OF  SODA.  The  process  of  Mr.  James  Young  for  tlie  preparation  of  stan- 
nate  of  soda,  presents  a  very  beautiful  application  of  science.  Instead  of  reducing  metallic 
t'n  from  the  ore,  and  oxidating  the  metal  again  to  form  the  stannic  acid  at  the  expense  of 
nitric  acid,  Mr.  Young  takes  the  native  peroxide  of  tin  itself,  and  fuses  it  with  soda.  The 
iron  and  other  foreign  metals  present  in  the  ore  are  insoluble  in  the  alkali,  so  that  by  solu- 
tion of  the  fused  mass  in  water,  a  pure  stannate  of  soda  is  olitained  at  once.  It  is  crystal- 
lized by  evaporation,  and  obtained  in  elllorescent  crystals  containing  nine  equivalents  of  water. 

STEAM  is  a  chemical  compound  of  oxygen  and  hydrogen,  in  the  proportion  of  8  parts 
by  weight  of  oxygen,  to  1  of  hydrogen.  Its  composition  by  volume  is  such,  that  the  quan- 
tity of  steam  which,  if  it  were  a  perfect  gas,  would  occupy  1  cubic  foot  at  a  given  pressure 
and  temperature,  contains  as  much  oxygen  as  would,  if  uncombined,  occupy  half  a  cubic 
foot,  and  as  much  hydrogen  as  would,  if  uncombined,  occupy  1  cubic  foot,  at  the  same  pres- 
sure and  temperature ;  so  that  steam,  if  it  were  a  perfect  gas,  would  occupy  two-thirds  the 
si)ace  which  its  constituents  occupy  when  uncombined.  Hence  is  deduced  the  following 
composition  of  the  weight  1  cubic  foot  of  steam  would  have  at  the  temperature  of  32' 
Fahr.,  and  pressure  of  one  atmosphere,  (or  14'7  lbs.  on  the  square  inch,)  if  steam  were  a  per- 
fect gas,  and  if  it  could  exist  at  the  pressure  and  temperature  stated 

Data  from  the  Expenments  of  Regnault. 

Half  a  cubic  foot  of  oxygen  at  a  pressure  of  one  atmosphere  ib. 

and  temperature,  32"' 0-044628 

1  cubic  foot  of  hydrogen 0-005592 


1  cubic  foot  of  steam  in  the  ideal  state  of  perfect  gas,  at  one 

atmosphere  and  32" 0-050220 

If  steam  were  a  perfect  gas,  the  weight  of  a  cubic  foot  could  be  calculated  for  auy  given 
pressure  and  temperature  by  the  following  formula: — 

Weight  of  a  cubic  foot  =  0-05022  lbs.  x  pressure  in  atmosphere — 

493-°2 
Temp.+4-61-°2 
For  example,  at  one  atmosphere  of  pressure,  and  212',  the  weight  of  a  cubic  foot  of  steam 
would  be; — 

0-05022  X  "^  =  0-03679  lb. 

673-'6 

But  steam  is  known  not  to  be  a  perfect  gas;  and  its  actual  density  is  greater  than  that 
which  is  given  by  the  preceding  formula,  though  to  what  extent  is  not  yet  known  by  direct 
experiment.  The  most  probable  method  of  indirectly  determining  the  density  of  steam,  is 
by  computation  from  the  latent  heat  of  evaporation,  from  which  it  appears  that  at  one  at- 
mosphere and  212°,  the  weight  of  a  cubic  foot  of  steam  is  probably  0-0379  lb.  The  great- 
est pressure  under  which  steam  <;an  exist  at  a  given  temperature,  is  called  the  pressure  of 
sa'Hra(io7i  for  steam  of  a  given  temperature.  The  temperature  is  called  the  boiling  point 
of  water  under  the  given  temperature.  The  pressure  of  saturation  is  the  only  pressure  at 
which  steam  and  liquid  water  can  exist  together  in  the  same  vessel  at  a  given  temperature. 

It  becomes  necessary  to  understand  correctly  the  method  of  determining  fixed  tempera- 
tu'  es  by  certain  phenomena  taking  place  at  them.  Thus  ice  begins  to  melt  at  a  point, 
which  we  call  the  Freezing  Point,  marked  32°  upon  the  scale  devised  by  Fahrenheit,  (see 
TiiEKMo.METEK,  vol.  ii ;)  and  we  determine  the  Boiling  Point  of  water  to  be  212°  on  the  same 
sc  de,  under  the  average  atmospheric  pressure  of  14-7  lbs.  on  the  square  inch  ;  2116-4  lbs.  on 
the  square  foot;  29-992  inches  of  the  column  of  mercury.  At  this  latter  point  water  ceases 
to  be  li'jiiid,  and  becomes  vaporiform.  F^-om  32"  to  212°,  all  the  heat  which  lias  been  jioured 
into  the  water,  has  effected  no  change  of  physical  conclition,  but  the  higher  temperature 
being  reached,  a  new  condition  is  established,  and  steam  is  produced — this  steam  then  be- 
ginning to  act  according  to  certain  lixed  laws. 

A  cubic  inch  of  water ^  evaporated  under  the  ordinarji  atino.iphcric  prcsstire,  is  converted 
into  a  cubic  foot  of  xteam. 

A  cubic  inch  of  ivater,  evaporated  under  the  at7nosphcric  pressure,  gives  a  mechanical 
force  equal  to  what  would  raise  a  ton  weiffht  1  foot  high. 

These  are  the  cfTects  produced  at  212'  under  the  above-named  pressure. 

Careful  experiments  have  determined,  within  very  small  limits  of  erroi-,  the  following 
facts: — Steam  under  pressure  of  35  lbs.  per  square  inch,  and  at  the  temperature  of  '2t'A°, 
0  ;ert3  a  force  eijual  to  a  ton  weight  raised  one  foot;  under  the  ])ressure  of  15  11  is.  and  at 
the  temperature  of  213°,  it  is  2,086  lbs.,  or  al)out  sevi'U  per  cent,  less;  and  under  70  lbs. 
and  at  306°  it  is  2,382  lbs.,  or  nearly  six  and  a  half  per  cent,  more  than  a  ton  raised  a  foot. 
It  ia  sufficient  for  all  practical  purposes  to  assume  that  each  cubic  inch  evaporated,  whatevet 
be  the  pressure,  develops  a  gross  mechanical  effort  equivalent  to  a  ton  weight  raised  1  foot. 

As  a  given  power  is  produced  by  a  given  rate  of  evaporation,  to  determine  this  the  fol- 
lowing rules  are  applieal)le: — 


996 


STEAM. 


To  produce  the  force  expressed  by  one-horse  power,  the  evaporation  per  minute  must 
develoj)  a  mechanical  force  equal  to  33,000  lbs.,  or  about  15  tons  raised  1  foot  high.  Fif- 
teen culiic  inches  of  water  would  accordingly  produce  this  effect,  which,  without  evaporation 
would  be  equivalent  to  900  cubic  inches  per  hour.  To  find,  therefore,  the  gross  power 
developed  by  a  boiler,  it  would  l)e  only  necessary  to  divide  the  number  of  cubic  inches  of 
water  evaporated  per  hour  by  900.  If,  therefore,  to  900  cubic  inches  be  added  the  quantity 
of  water  per  hour  necessary  to  move  the  engine  itself,  independently  of  its  load,  we  shall 
obtain  the  quantity  of  water  per  hour  which  must  be  supplied  by  the  boiler  to  the  engine 
for  each  horse  power,  and  this  will  be  the  same  whatever  may  be  the  magnitude  or  propor- 
tions of  the  cylinder.  In  the  application  of  steam  power,  the  most  economical  means  have 
been  attained  in  the  pumping  engines  of  Cornwall,  where  the  steam  is  employed  expansively. 
The  following  Tables  will  show  the  value  of  the  Cornish  engines. 

General  Table  of  the  Action  of  Cornish  Steam  Engines. 


Month 

ending 

August. 

Sept. 

Oct. 

Nov. 

Dec. 

Number  reported       .        .       .       .        - 

July  'JO. 

23 

24 

24 

24 

24 

24 

oi 

Average  load  per  square  inch  on  piston, 

B 

in  lbs. -        - 

119 

11-4 

11-5 

11-8 

12-5 

12-7 

Ml 

Average  number  of  strokes  per  minute    - 

4-8 

4-8 

5-3 

5-2 

53 

5-6 

§ 

Gallons  of  water  drawn  per  minute  - 

8,773 

8,980 

8,772 

4,031 

4,373 

4,000 

BO        i 

Average  duty— being  million  lbs.  lifted  1 

■g. 

foot  high  by  the  consumption  of  1  cwt. 

of  coals 

61 -1 

59-5 

67-2 

63-4 

649 

63-9 

3 

Actual  horse-power  employed   -        -        . 

710-8 

740-1 

725-8 

787-8 

845-8 

814-6 

Cui 

Average  consumption  of  coals  per  horse- 

power per  horse,  in  lbs.  -        -        -        - 

4-0 

4-1 

3-5 

4-3 

41 

4-1 

Number  reported 

IS 

IS 

18 

18 

19 

19 

Number  of  kibbles  drawn  •        -        -        - 

62,608 

66,162 

65,645 

68,895 

71,135 

74,705 

a  g 

Average  depth  of  drawing,  in  fathoms 

130-4 

135-6 

131-5 

129-2 

131-7 

130-3 

~  S    ■ 

Average  number  of  horse  whim-kibbles, 

b»  to 

of  3  cwt.  drawn  the  average  depth,  by 

o 

consuming  1  cwt.  of  coals 

49  0 

49-7 

47-8 

51-7 

51-6 

66-6 

M^      . 

Average  duty,  as  above      .... 

11-8 

121 

18-2 

16-3 

16-0 

165 

o  S 

Number  reported 

6 

6 

6 

6 

6 

6 

c5  a 

Average  number  of  strokes  per  minute    - 

13-9 

14-0 

14-8 

14-9 

14-1 

13-8 

Average  dutv,  as  above       .        .        .        - 

30  6 

80-3 

28-6 

30-0 

82-3 

81-9 

Vj  " 

Horse  power  employed      .        -        .        . 

88-5 

90-1 

54-9 

58-2 

104-9 

111-1 

Great  Polgooth  -        -    SOincb  single 

90-5 

90-3 

86-2 

93-8 

90-7 

86-0 

Par  Consols         -        -    72   and  30-inch 

XA^ 

Sims'  combined 

89-9 

94-1 

88-3 

92-0 

94-5 

. 

Fowey  Consols  -        -     80-inch  single 

87-8 

93-0 

102-8 

100  5 

96-4 

921 

Par  Consols         -        -     80-inch  single 

84-2 

44-1 

87-5 

89-3 

90-0 

89-6 

-  •-  ~ij 

i  Callinston  Mines        -    50-inch  single 

821 

78-1 

70-4 

62-5 

67-0 

72-0 

Ph  "5    [ 

Trelawny   .      .  -        -    50-inch  single 
Par  Consols        -        -    2-1  and   13-inch 

77-4 

70-3 

• 

73-9 

67  0 

74-7 

Sims'  combined 

31  0 

29-3 

28-5 

88-8 

27  0 

27-1 

E  S  d 

Fowey  Consols  -        -    22-inch  double     - 

25-1 

26-2 

25-2 

21-9 

24-7 

24-6 

Fowey  Consols  -        -    22-inch  double     - 

20-3 

19-5 

18-3 

20-8 

24-2 

239 

^  g'° 

Callington  Mines        -    22-inch  double     - 

17-2 

18-9 

16-8 

- 

. 

- 

Par  Consols        -        -    24-inch  sinsrle 

16-0 

16-3 

. 

. 

. 

15-4 

Fowey  Consols  •        .    18-inch  double     - 

15-4 

. 

. 

. 

. 

=  S  - 

Tamar  Mines      -        -    30-inch  single 

43-3 

44-4 

41-4 

45-8 

441 

39-2 

"E.S  5 

Great  Polgooth  -        -    26-inch  double      - 

33-4 

40-8 

24-8 

29-4 

S  5r.1i 

South  Caradon   -        .    26-inch  single 

SO-3 

. 

32  0 

803 

317 

35-5 

01  *        '• 

Tincroft      -       -       -    S6-inch  double     - 

29-8 

35-0 

88-5 

44-0 

Average  Duty  of  Cornish  Steam  Engines. 


184S. 

No.  of  pumping 

engines. 

Quantity  of  coal 
consumed. 

Water  lifted  10 
fathoms  high. 

Average  duty.* 

Tons. 

Tons. 

lbs. 

January      -         -         -         . 

27 

2,285 

22,000,000 

54,000,000 

February    .         •         -         - 

31 

2,540 

25,000,000 

57,000,000 

March         .... 

28 

3,523 

33,000,000 

54,000,000 

April           -         .         -         - 

21 

2,608 

25,000,000 

53,000,000 

May 

27 

2,253 

22,000,000 

54,000,000 

June 

27 

2,544 

24,000,000 

54,000,000 

July 

26 

1,917 

18,000,000 

54,000,000 

August       .... 

26 

1,780 

16,000,000 

53,000,000 

September           ... 

25 

2,038 

18,000,000 

52,000,000 

October      .... 

25 

1,618 

14,000,000 

53,000,000 

November  .... 

26 

2,168 

19,000,000 

50,000,000 

December  -        .        .        - 

25 

1,923 

17,000,000 

50,000,000 

*  The  average  duty  in  fifth  coluum  gives  the  number  of  lbs.  lifted  one  foot  high  by  the  consumption 
ef  a  bushel  of  coal. 


STEEL. 


997 


Abstract  of  the  Duty  of  Pumping  Engines  in  Cornwall. 


Year. 

Number  of 

Average  duty. 

BEST  ENOINE. 

reporied. 

Name  of  mine. 

Desoripllon. 

Engineers. 

Highest  duty. 

1S22 

52 

28,900,000 

Wheal  Abrabaru. 

Double  cylinder. 

Woolf. 

47,200,000 

1S23 

52 

28,200,000 

Do. 

Do. 

Do. 

51,000,000 

1S24 

49 

28.300,00(1 

Polsooth. 

SO-in.  cylinder. 

Sims. 

46,90tt,0O(l 

1S25 

5G 

32,000,000 

D... 

Do. 

Do. 

54,000,000 

1S26 

51 

30,500.000 

"Wheal  Vor. 

Do. 

Sims  &,  Richards. 

50.000,000 

1827 

51 

32,lO;>,o;»o 

Wheal  Towan. 

Do. 

Grose. 

62,200,000 

1S28 

57 

37,000,000 

Do. 

Do. 

Do. 

87,000,000 

1S29 

53 

41,700,000 

Do. 

Do. 

Do. 

82,000,000 

1S30 

5G 

4;j,3oo,ooo 

Do. 

Do. 

Do. 

77,900,000 

13-31 

58 

4:3,400,000 

Do. 

Do. 

Do. 

77,700,000 

1S32 

59 

45,000,000 

Whral  Vor. 

Do. 

Elchards. 

91,400,000 

H33 

5S 

46,600.000 

Do. 

Do. 

Do. 

8S,.^00,000 

183-t 

52 

47,800,0  0 

Fowey  Consols. 

Do. 

West. 

97,900,000 

1835 

51 

47,800,000 

Do. 

Do. 

Do. 

95,800,000 

1836 

61 

46,600.000 

Wheal  Darlinston. 

Do. 

Eustis. 

95,400,000 

1837 

58 

47,000,000 

Fowey  Consols. 

Do. 

We.st. 

85,000,000 

1833 

61 

50,000,000 

Wheal  Darlington. 

Do. 

Eustis. 

78,100,000 

1839 

52 

55.000,O;)0 

Fowey  Consols. 

Do. 

West. 

77,800,000 

1840 

54 

51,000,000 

WHieal  Darlington. 

Do. 

Eustice. 

81,700,000 

1841 

56 

54,700,000 

United  Mines. 

85-in.  cylinder. 

Hocking  &  Loam. 

101,900,000 

1842 

49 

53,800,000 

Do. 

Do. 

Do. 

107,500,000 

1843 

36 

60,000,000 

Do. 

Do. 

Do. 

96,100,000 

In  an  inquiry  upon  the  incrustations  of  the  boilers  of  steam  vessels,  by  M.  Couste,  it  is 
stated  that  8  or  10  per  cent,  of  the  heat  of  fuel  is  lost  after  the  first  few  days'  work — at  Bor- 
deau-x:  15  per  cent.,  and  at  Havre,  after  some  days'  constant  work  and  observation,  40  per 
cent.  ;  in  general  practice  it  has  been  estimated  that  40  per  cent,  of  the  heat  of  the  fuel  has 
been  lost  by  the  internal  incrustations  and  deposits  in  the  boilers  of  steam  vessels. 

Tl«  followincr  results  were  obtained  from  French  ocean  steamers: — 


Stations. 

Sulphate  of 
Lime. 

Carbonate  of 

Magnesiii. 

Free 
Magnesia. 

Iron  and 
Alumina. 

Water. 

Hamburg,  deposit  from  the  Burface  of  the  boiler 

(partly  crystallized) 

.Mediteiranean,  tubular  boiler  (amorphous)   - 
-Mediterranean,  (amorphous  deposit)      .        .        - 

85-20 
84-94 
80-90 

2-25 
2-34 
3-19 

5-95 

7-66 

10-35 

0-41 
C-50 

6-5 

4-65 

4-56 

An  essential  character  of  the  sea-water  incrustations  is  that  they  are  free  from  the 
deposit  of  calcareous  carbonates. 

STEEL  {Acici^  Fr. ;  Stahl,  Germ.)  is  a  carburet  of  iron,  more  or  less  freed  from  foreign 
matter,  and  may  be  produced  by  two  processes  opposed  to  each  other.  First,  by  working  pig 
iron,  whicli  contains  4  or  5  per  cent,  of  carbon,  in  a  suitable  furnace,  until  such  carbon  is 
reduced  to  th.it  quantity  required  for  constituting  steel,  which  is  about  1  per  ceflt.  ;  the  sec- 
ond method  is  to  heat  iron  bars  in  contact  with  charcoal,  until  they  have  absorbed  that 
quantity  of  carbon  which  may  be  required. 

Steel  may  be  classed  into  three  kinds: — 

1st.  Natural  steel,  which  is  manufactured  from  pig  iron  direct. 

2d.  Cemented  or  converted  steel,  which  is  produced  by  the  carbonization  of  wrought  iron. 

3d.  Cast  steel,  which  is  produced  by  the  fusion  of  either  natural  or  cemented  steel,  but 
principally  from  the  latter. 

The  various  kinds  of  iron  which  arc  used  for  the  manufocture  of  steel  are  imported 
principally  from  Sweden,  Norway,  and  Russia ;  but  the  high  price  of  Swedish  and  other  steel 
iron  has  for  the  past  few  years  compelled  the  consumers  to  look  elsewhere  for  a  supply  of 
foreign-made  iron,  whilst  at  the  same  time  every  encouragement  has  been  offered  to  Engli.sh 
manufacturers  so  to  improve  their  steel  irons  as  to  render  them  at  lea.st  suitable  for  the  pro- 
duction of  steel  good  enough  for  tlie  manufacture  of  coach  springs  and  such  other  purposes. 

England  now  furnishes  a  large  quantity  of  iron  suitable  for  steel  purposes,  which  may 
be  estimated  at  20,000  tons  per  annum  ;  this  iron  is  manufactured  with  great  care,  often 
with  an  admixture  of  charcoal  pig  iron,  aiul  various  chemical  reactives,  which  arc  atided  at 
the  caprice  of  each  manul'acturer,  but  the  object  of  which  is  to  discharge  the  deleterious 
matters  and  to  reduce  the  semi-metals.  • 

It  is  of  the  highest  importance  that  the  iron  used  for  steel  purposes  should  be  as  pure 
and  free  from  foreign  matters  as  possible ;  those  irons  which  at  present  enjoy  the  highest 
reputation  are  tho.se  manufactured  from  the  Danncmora  ores  in  Sweden  ;  the  whole  of  the 
steel  irons  produced  in  that  country  are  smelted  from  the  black  oxides,  containing  usually 
60  per  cent,  of  metal. 

Natural  or  German  steel  is  so  called  becau.se  it  is  produced  direct  from  pig  iron,  the 
result  of  the  fusion  of  the  spathosc  iron  ores  alone,  or  in  a  small  degree  mixed  with  the 


998  STEEL. 

brown  oxide ;  these  ores  produce  a  highly  crystalline  raetal,  called  spiegle-eisen  on  account 
of  the  large  crystals  the  metal  presents.  This  crude  iron  contains  4  to  5  per  cent,  of  car- 
bon, and  4  to  5  per  cent,  of  manganese.  Karsten,  Hassengratz,  Marcher,  and  Reaumur, 
all  advocate  the  use  of  gray  pig  iron  for  the  production  of  steel ;  indeed  they  distinctly 
state  that  the  best  qualities  cannot  be  produced  without  it ;  they  state  correctly  that  the 
object  of  working  it  in  the  furnace  is  to  clear  away  all  foreign  matters,  but  there  can  be  no 
advantage  gained  by  retaining  the  carbon,  and  combining  it  with  the  iron.  This  theory  is 
incoriect,  although  it  is  supported  by  such  high  authorities ;  gray  iron  contains  the  maxi- 
mum (juantity  of  carbon,  and  consetjuently  remains  for  a  longer  time  in  a  state  of  fluidity 
than  iron  containing  less  carbon;  the  metal  is  not  only  mixed  up  with  the  foreign  matter  it 
may  itself  contain,  but  also  that  with  which  it  may  become  mixed  in  the  furnace  in  which 
it  is  worked.  This  prolonged  working,  which  is  necessary  in  order  to  bring  highly  carbon- 
ized metal  into  a  malleable  state,  increases  the  tendency  to  produce  silicated  oxides  of  iron; 
these  mixing  with  the  steel  produced  render  it  red  short,  and  destroy  many  good  qualities 
which  the  pig  iron  may  have  originally  possessed.  The  semi-metals  produced  tend  also  to 
prevent  malleability;  the  use  of  highly  carbonized  it7(j7e  ^ii^  iro7i  is  equally  inapplicable, 
and  cuases  a  laige  consumption  of  charcoal,  as  well  as  waste  of  metal.  In  Austria,  where 
a  large  (juantity  of  natural  steel  is  produced,  the  fluid  metal  is  tapped  from  the  blast  furnace 
into  a  round  hole  ;  water  is  sprinkled  on  the  surface,  which  chills  it,  and  thus  forms  a  cake 
about  half  an  inch  thick.  This  is  taken  from  the  surface,  and  the  operation  is  again  per- 
formed until  the  whole  is  formed  into  cakes;  they  are  then  piled  edgewise  in  a  furnace,  and 
covered  with  charcoal,  and  heated  a  full  red  heat  for  about  48  hours  ;  by  this  process  much 
of  the  carbon  is  discharged.  These  cakes  are  then  used  for  producing  steel  in  the  refinery. 
A  much  superior  quality  is  thus  obtained  with  greater  economy.  It  appears  that  the  most 
perfect  plan  for  manufacturing  the  steel  is  to  free  the  crude  metal  as  much  as  possible  from 
its  impurities  whilst  in  a  fluid  state.  There  is  a  process  patented  by  Mr.  Charles  Sandei-son 
of  Shetfield,  which  fulfils  all  that  is  required.  The  crude  metal  is  melted  on  the  bed  of  a 
reverberatory  furnace,  and  any  chemical  reagent  is  added  capable  of  disengaging  oxygen 
during  its  decofnposition.  Carbonic  acid  or  carbonic  oxide  gases  are  produced  by  thB  union 
of  the  oxygen  with  the  carbon  contained  in  the  fluid  iron,  which  is  thus  eliminated ;  the 
gases  so  produced,  being  unable  to  reenter  the  metal,  either  pass  off"  in  vapor,  or  act  upon 
the  silicates  or  other  earthy  compounds  which  the  crude  iron  may  contain,  precipitating  the 
metallic  part  and  allowing  the  earthy  matter  to  flow  away  as  slag  :  a  refined  metal  is  thus 
produced  of  veiy  great  purity  for  the  production  of  steel.  The  metal  itself  being  to  some 
extent  decarbonized,  the  steel  is  more  quickly  produced,  which  secures  economy  in  charcoal, 
time,  and  waste  of  metal,  &c.  ;  the  purity  of  the  metal  also  prevents  the  formation  of  those 
deleterious  compounds,  which,  when  they  are  incorporated  with  the  steel,  seriously  injure 
the  quality.  Natural  steel  manufactured  from  this  purified  iron  has  been  found  of  very 
supeiior  quality,  and  more  uniform.  The  furnaces  used  for  the  production  of  natural  steel 
are  like  the  refineries  in  which  charcoal  iron  is  produced.  In  all  countries  their  general 
construction  is  the  same,  but  each  lias  its  own  peculiar  mode  of  working.  We  find,  there- 
fore, the  (German,  the  8tyrian,  the  Carinthian,  and  several  other  distinct  methods,  yet  all 
producing  steel  from  crude  iron  directly,  although  pursuing  different  modes  of  operation. 
These  differences  arise  from  the  nature  of  the  pig  iron  each  country  jjroduces,  and  the 
peculiar  habits  of  the  workmen.  These  modified  processes  do  not  affect  the  thcori/  of  the 
manufacture  of  the  steel,  but  rather  accommodate  themselves  to  the  peculiar  character  of 
the  metal  produced. 

Fiff.  014  .sliows  a  ground  plan  of  the  furnace;  fg.  G15  an  elevation;  and  /?</.  616  the 
form  of  the  fire  itself  and  the  position  of  the  metal  within  it.  The  fire,  d,  is  24  inches  long 
and  24  inches  wide ;  a,  a,  a  are  metal  plates,  surrounding  the  furnace. 

Fi(i.  015  shows  the  elevation,  usually  built  of  stone,  and  braced  with  iron  bars.  The 
fire,  o,  is  16  inches  deep  and  24  inches  wide  ;  before  the  tuyfere,  at  b,  a  space  is  left  under 
the  fire,  to  allow  the  damp  to  escape,  and  thus  keep  the  bottom  dry  and  hot. 

In  tif/.  014  there  are  two  tuyeres,  but  only  one  tuyere  iron,  which  receives  both  the 
blast  nozzles,  which  are  so  laid  and  directed  that  the  currents  of  air  cross  each  other,  as 
shown  !)y  tlie  dotted  lines ;  the  bla.<t  is  licjit  as  regular  as  possible,  so  that  the  fire  may  be 
of  one  uniform  heat,  whatever  intensity  may  be  required. 

Fip.  010  shows  the  fire  itself,  with  the  metal,  charcoal,  and  blast,  a  is  a  bottom  of 
charcoal,  rammed  down  very  close  and  hard,  b  is  another  bottom,  but  not  so  closely 
beaten  down  ;  this  l)ed  of  charcoal  protects  the  under  one,  and  serves  also  to  give  out  car- 
bon to  the  loop  of  steel  during  its  production,  c  is  a  thin  stratum  of  metal,  which  is  kept 
in  the  fire  to  suri'ound  the  loop.     D  shows  the  loop  itself  in  progress. 

When  the  fire  is  hot,  tlie  first  operation  is  to  melt  down  a  portion  of  pig  iron,  say  50  to 
70  pounds  according  as  the  pig  contains  more  or  less  carbon  ;  the  charcoal  is  pushed  back 
from  the  upper  part  of  the  fire,  and  the  bla.st,  which  is  then  reduced,  is  allowed  to  play 
upon  the  surface  of  the  metal,  adding  from  time  to  time  some  hammer  slack,  or  rich  cinder, 
the  result  of  the  previous  loop.     All  these  operations  tend  to  decarbonize  the  metal  to  a 


STEEL. 


999 


certain  extent ;  the  mass  begins  to  thicken,  and  at  length  becomes  solid.  The  workman 
then  draws  together  the  charcoal  and  melts  down  another  portion  of  metal  upon  the  cake ; 
this  operation  renders  the  face  of  the  cake  again  fluid,  but  the   operation  of  decarboni- 


614 


zation  being  repeated  in  the  second  charge,  it  also'  thickens,  incorporates  itself  with  the 
previous  cake,  and  the  whole  becomes  hard ;  metal  is  again  added  until  the  loop  is  com- 
pleted. During  these  successive  operations,,  the  loop  is  never  raised  before  the  blast,  as  it 
is  in  making  iron,  but  it  is  drawn  from  the  fire  and  hammered  into  a  large  bloom,  which  is 
cut  into  several  pieces,  the  ends  being  kept  separated  from,  the  middle  or  more  solid  parts, 
which  are  the  best. 

This  operation,  apparently  so  simple  in  itself,  requires  both  skill  and  care ;  the  workman 
has  to  judge,  as  the  operation  proceeds,  of  the  amount  of  carbon  which  lie  has  retained  from 
the  pig  iron  ;  if  too  much,  the  result  is  a  very  raw,  crude,  untreatable  steel ;  if  too  little,  he 
obtains  only  a  steelified  iron  ;  he  has  also  to  keep  the  cinder  at  a  proper  degree  of  fluidity, 
which  is  modified  from  time  to  time  by  the  addition  of  quartz,  old  slags,  &c.  It  is  usual  to 
keep  from  two  to  three  inches  of  cinder  on  the  face  of  the  metal,  to  protect  it  from  the 
direct  action  of  the  blast.  The  fire  itself  is  formed  of  iron  plates,  and  the  two  charcoal 
bottoms  rise  to  within  nine  inches  of  the  tuyere,  which  is  laid  flatter  than  when  iron  is 
being  made.  This  position  of  the  tuyere  causes  the  fire  to  work  more  slowly,  but  it  insures 
a  better  result. 

The  quantity  of  blast  required  is  about  180  cubic  feet  per  minute.  Good'  workmen 
make  7  cwt.  of  steel  in  17  hours.  The  waste  of  the  pig  iron  is  from  20  to  25  per  cent.,  and 
the  quantity  of  charcoal  consumed  is  240  bushels  per  ton.  The  inclination  of  the  tuyere  is 
12  to  15  degrees.  The  flame  of  the  fire  is  the  best  guide  ibr  the  workmen..  During  its 
working  it  shouhl  be  a  i-ed  ))luish  color.     When  it  becomes  whitcthefire  is  working  too  liot. 

From  this  desciiption  of  the  process,  it  will  be  evident  tliat  pig  iron  will  require  a  much 
longer  time  to  dinar) )<)nize  than  the  cakes  of  metal  which  have  been  roasted,  a«  already  de- 
scribed; and,  again,  it  must  be  evident,  that  a  purified  and  decarbonized  moV.d  must  be  the 
best  to  secure  a  good  and  ecjual  quality  to  tl\e  Steel,,  since  tlic  purified  metal  is  more  homo- 
geneous than  tlie  crude  iron. 

When,  therefore,  care  lias  been  taken  in  melting  down  each  portion  of  metal,  and  a 
complete  and  perfect  layer  of  steel  has  been  obtained  after  each  successive  molting  ;  when 
the  cinder  has  had  due  attention,  so  that  it  has  been  neither  too  thick  nor  too  thin,  and  the 


1000  STEEL. 

heat  of  the  fire  regulated  and  modified  during  the  progressive  stages  of  the  process,  then  a 
good  result  is  obtained  ;  a  fine-grained  steel  is  produced,  which  draws  under  the  hammer, 
and  hardens  well.  However  good  it  may  be,  it  possesses  one  great  defect ;  it  is  this  : 
during  its  manufacture,  irotL  is  produced  along  with  the  steel,  and  becomes  so  intimately 
mixed  up  with  it,  that  it  injures  the  otherwise  good  qualities  of  the  steel  ;  the  iron  becomes, 
as  it  were,  interlaced  throughout  the  mass,  and  thus  destroys  its  hardening  (|ua!ity.  •  When 
any  tool  or  instrument  is  made  from  natural  steel,  without  it  has  been  well  refined,  it  will 
not  receive  a.  peruiaucnt  cutting  edge;  the  iron  part  of  the  mass,  of  couise,  not  being  hard, 
the  tool  cuts  only  upon  the  steel  portion ;  the  edge,  therefore,  very  soon  becomes  destroyed. 
There  is  another  defect  in  natural  steel,  but  it  is  of  less  importance.  When  too  much  car- 
bon has  been  left,  the  steel  is  raw  and  coarse,  and  it  draws  veiy  imperfectly  under  the 
hammer ;  the  articles  manufactured  from  such  steel  often  break  in  hardening ;  thus  it  is 
evident  that,  in  producing  this  kind  of  steel,  every  care,  skill,  and  attention  is  required  at 
the  hands  of  the  workman.  These  defects  very  materially  aftfcct  the  commercial  value  of 
the  steel ;  the  irregular  quality  secures  no  guarantee  to  the  consmner  that  the  tools  shall  be 
perfect,  and,  consequently,  it  is  not  used  for  the  most  important  purposes ;  yet,  w  hen  the 
raw  steel  is  refined,  it  becomes  a  very  useful  metal,  and  is  largely  used  in  Westphalia  for 
the  manufiicture  of  hardware,  scythes,  and  even  swords.  It  possesses  a  peculiarity  of  re- 
taining its  steel  quality  after  repeated  heating.  This  property  renders  it  very  useful  for 
mining  and  many  other  purposes. 

The  raw  steel,  being  so  imperfect,  is  not  considered  so  much  an  article  of  commerce 
with  the  manufacturer,  but  it  is  sold  to  the  steel  refiners,  who  submit  it  to  a  process  of 
welding.  The  raw  steel  bloom  is  drawn  into  bars,  one  or  two  inches  wide  and  half  an  inch 
thick,  or  less  ;  a  number  of  these  are  put  together  and  welded  ;  these  bars  are  then  thrown 
into  water,  and  they  are  broken  in  smaller  pieces  to  examine  the  fracture  ;  those  bars  which 
are  equally  stcelified  are  mixed  together.  In  manufacturing  refined  steel,  the  degree  of 
hardness  is  selected  to  suit  the  kind  of  article  which  it  is  intended  to  make.  A  bar,  two  to 
three  feet  long,  |brnis  the  top  and  bottom  of  the  bundle,  but  the  inside  of  the  packet  is  fill- 
ed with  the  small  pieces  of  selected  steel.  This  packet  is  then  placed  in  a  hollow  fire,  and 
carefully  covered  from  time  to  time  with  pounded  clay,  to  form  a  coat  over  the  metal,  and 
preserve  it  from  the  oxidizing  influence  of  the  blast.  W' hen  it  is  at  a  full  welding  heat  it 
is  placed  under  a  hammer,  and  made  as  sound  and  homogeneous  as  possible  ;  it  is  again  cut, 
doubled  together,  and  again  welded.  For  very  fine  articles,  the  refining  is  increased  by 
several  doublings,  but  this  is  not  carried  at  present  to  so  great  an  extent  as  formerly,  since 
cast  steel  is  substituted,  being  in  many  cases  cheaper.  Although  the  refined  natural  steel 
is  very  largely  consumed  in  Germany,  and  also  in  Austria,  yet  a  considerable  quantity  is 
exported  to  South  America,  the  United  States,  and  to  Mexico.  The  Levant  trade  takes  a 
large  portion,  and  is  supplied  from  the  Styrian  and  Carinthian  forges.  This  is  shipped  from 
Trieste ;  it  is  sold  in  boxes  and  bundles.  That  in  boxes  is  marked  No.  00,  up  to  4.  The 
00  is  the  smallest,  being  about  J  in.  square  ;  number  4  is  about  ^  in.  ;  0,  1,  2,  and  3  being 
the  intermediate  sizes.  It  is  broken  into  small  pieces,  about  3  to  7  inches  long.  In  bundles 
of  100  lbs.  the  steel  is  drawn  to  various  sizes,  and  is  so  packed.  A  large  portion  is  sent  to 
the  East  Indies,  and  also  to  the  United  States. 

The  average  price  of  that  sold  in  boxes  is  £20  to  £24  per  ton;  in  bundles,  £17  to 
£20 ;  and  the  raw  steel,  as  sold  to  the  refiners,  £15  to  £18  per  ton  ;  whilst  the  refined  steel 
increases  in  price  according  to  the  number  of  times  it  has  been  refined. 

Natural  steel  being  expensive,  many  attempts  were  made  in  W^estphalia  to  produce  a 
kind  of  steel  by  puddling  pig  iron  in  a  peculiar  manner ;  a  patent  was  taken  out  in  England 
by  Mr.  Ricpe,  and  a  considerable  quantity  of  this  steel  is  produced.  In  Mr.  Riepe's  de- 
scription of  this  process  he  says  : — 

"  I  employ  the  puddling  furnace  in  the  same  way  as  for  making  wrought  iron.  I  intro- 
duce a  charge  of  about  280  lbs.  of  pig  iron,  and  raise  the  temperature  to  redness.  As  soon 
as  the  metal  begins  to  fuse  and  trickle  down  in  a  fluid  state,  the  damper  is  to  be  partially 
clo.sed  in  order  to  temper  the  heat.  From  12  to  IG  shovelfuls  of  iron  cinder  discharged 
from  the  rolls  or  squeezing  machine  are  added,  and  the  whole  is  to  be  uniformly  melted 
down.  The  mass  is  then  to  be  puddled  with  the  addition  of  a  little  black  oxide  of  man- 
ganese, common  salt,  and  dry  clay,  previously  ground  together.  After  this  mixture  has 
acted  for  some  minutes,  the  damper  is  to  be  fully  opened,  when  about  forty  pounds  of  pig 
iron  are  to  be  put  into  the  furnace,  near  the  fire  bridge,  upon  elevated  beds  of  cinder  pre- 
pared for  that  purpose.  W^hen  this  pig  iron  begins  to  trickle  down,  and  the  mass  on  t-lie 
l)uttom  of  the  surface  begins  to  boil  and  throw  out  from  the  surfiice  the  well-known  blue 
jets  of  flame,  the  said  pig  iron  is  raked  into  the  boiling  mass,  and  the  whole  is  then  well 
mixed  together.  The  mass  soon  begins  to  swell  up,  and  the  small  grains  begin  to  form  in  it 
and  break  through  the  melted  cinder  on  the  surface.  As  soon  as  these  grains  appear,  the 
dami)er  is  to  be  three-quarters  shut,  and  the  process  closely  inspected  while  the  mass  is 
being  puddled  to  and  fro  beneath  the  covering  layer  of  cinder.  During  the  whole  of  this 
process  the  heat  should  not  be  raised  above  cherry  redness,  or  the  welding  heat  of  shear 


STEEL. 


1001 


steel.  Tlie  blue  jets  of  flame  gradually  disappear,  while  the  formation  of  grains  continues, 
whi'jh  grains  very  soon  begin  to  luse  together,  so  that  the  mass  becomes  waxy  and  has  the  above 
mentioned  cherry  redness.  If  these  precautions  are  not  observed,  the  mass  would  pass 
mare  or  less  into  iron,  and  no  uniform  steel  product  could  be  obtained.  As  soon  as  the 
mass  is  finished  so  far,  the  tire  is  stirred  to  keep  the  necessary  lieat  fur  the  succeeding  opera- 
tion— the  damper  is  to  be  entirely  shut,  and  part  of  the  mass  is  collected  into  a  ball,  the  re- 
mainder always  being  kept  covered  with  cinder  slack.  Tliis  ball  is  brought  under  the  ham- 
mer, and  then  worked  into  bars.  The  same  process  is  continued  until  the  whole  is  work- 
ed into  bars.  When  I  use  pig  iron  made  from  sparry  iron  ore,  or  mixtures  of  it  with  other 
pig  iron,  I  add  onlv  about  2i)  lbs.  of  the  former  pig  iron  at  the  later  i)eriod  of  the  piocess 
instead  of  about  40  lbs.  Wiien  I  employ  Welsh  or  pig  iron  of  that  description,  1  throw  10 
lbs.  of  best  pi  istic  eliy,  in  a  dry  granulated  state,  before  the  beginning  of  the  process,  on 
the  bottom  of  the  furnace.  I  add  at  the  later  period  of  the  process,  about  40  lbs.  of  pig 
iron   as   before  described,  but  strew  over  it  clay  in  the  same  proportion  as  just  mentioned." 

This  steel  is  very  useful  for  ships'  plates,  being  very  strong  and  rigid,  and  thus  requiring 
less  weight  of  metal ;  it  may  also  eventually  be  used  for  rails  and  a  great  variety  of  pur- 
poses, for  which  at  present  strong  charcoal  or  scrap  iron  is  used.  Its  present  price  is  about 
£25  in  plates,  and  £16  in  bars. 

The  Paal  process  may  be  considered  as  an  improvement  upon  natural  steel,  the  object 
being  as  far  as  possible  to  carbonize  the  iron  fibres  whiph  this  kind  of  steel  always  contains. 
The  process  is  based  upon  the  old  one  of  Vanaccio ;  it  consists  in  plunging  iron  into  a  bath 
of  melted  metal.  The  carbon  of  the  metal  combines  with  the  iron,  and  in  a  very  short 
ti.ne  converts  it  into  steel.  This  process  was  carried  further  by  Vanaccio,  who  contrived 
to  add  wrought  iron  to  the  metal  until  he  had  decarbonized  it  sufficiently ;  this  was  found  to 
produce  a  steel,  but  unfit  for  general  use.  That  produced  by  plunging  iron  into  metal  was 
found  to  be  very  hard  steel  on  the  outside,  but  iron  within ;  wliile  that  produced  by  adding 
iron  to  the  metal  was  found  too  brittle  to  be  drawn.  The  Paal  method,  however,  is  a  de- 
cided improvement  in  the  manufacture  of  refined  natural  steel.  The  packets,  as  already 
described  in  the  refinement  of  natural  steel,  are  welded  and  drawn  to  a  bar ;  whilst  hot, 
they  are  plunged  into  a  bath  of  metal  for  a  few  minutes,  by  which  the  iron  contained  in  tiie 
raw  steel  becomes  carbonized,  and  thus  a  more  regular  steel  is  obtained  than  that  produced 
by  the  common  proces.s.  The  operation  requires  great  care,  for  if  the  bars  of  steel  be  left 
in  t'.ie  metal  too  long,  they  are  more  or  less  destroyed,  or  perhaps  entirely  melted.  It  com- 
mands a  little  higher  price  in  the  market,  and  is  chiefly  consumed  by  the  home  manufac- 
turers, excepting  a  portion  which  is  exported  to  Russia. 

The  foregoing  kinds  of  steel  may  be  classed  under  the  first  head  of  natural  steel,  being 
manufactured  from  the  crude  iron  direct. 

Tiie  next  process  is  the  production  of  steel  by  introducing  carbon  into  malleable  iron, 
whicli  is  the  reverse  of  the  process  already  described.  The  iron  to  bo  converted  is  placed 
in  a  furnace,  stratified  with  carbonaceous  matter,  and  on  heat  being  applied  the  iron  absorbs 
the  carl)on,  and  a  new  compound  is  thus  formed. 

When  this  process  was  discovered  is  not  known  ;  at  a  very  early  period  charcoal  was 
found  to  harden  iron,  and  to  give  it  a  better  and  more  permanent  cutting  edge.  It  seems 
probable  that  from  hardening  small  objects,  bars  of  iron  were  afterward  submitted  to  the 
same  process.  To  Reaumur  certainly  belongs  the  merit  of  first  bringing  the  process  of  con- 
version to  any  degree  of  perfection.  His  work  contains  a  vast  amount  of  information  upon 
the  theory  of  cementation  ;  and  although  his  investigations  are  not  borne  out  by  the  prac- 
tice of  the  present  day,  yet  the  first  principles  laid  down  by  him  are  now  the  guide  of  the 
converter.  Our  furnaces  are  nmch  larger  than  those  used  by  Reaumur,  and  tliey  arc  built 
so  as  to  produce  a  more  uniform  and  economical  result..  The  furnace  of  cementation  in 
which  bar  iron  is  converted  into  blistered  steel  is  represented  in  Jign.  G17,  618,  619. 


618 
I 


-x 


■■■■; 

;.^\^i(»5^^?^"--     - 

i^'i 

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0 

1 

1002 


STEEL. 


V  y,  /y/z'/y/y//,  y,  y.  yyy.'yy  yyyyyyyx^ 


It  is  rectangular,  and  covered  in  by  a  semicircular  arch,  in  the  centre  of  which  there  \& 
a  circular  hole  left,  12  inches  diameter,  which  is  opened  when  the  furnace  is  cooling.  It 
contains  two  chests  culled  "pots,"  c,  c,  made  either  of  fire-stone  or  fire-bricks;  each  "pot" 
is  3  feet  wide,  3  feet  deep,  and  12  feet  long.  One  is  placed  on  one  side,  and  the  other  on 
the  contrary  side  of  the  fire-grate,  a  b,  which  occupies  the  whole  length  of  the  furnace,  and 
is  13  to  14  feet  long;  the  grate  is  15  to  IC  inches  broad,  and  the  bars  rest  from  10  to  12 
inches  below  the  inferior  plane  or  bottom  level  of  the  "  pots ;"  the  height  of  the  arch  at 
the  centre  is  h\  feet  above  the  top  of  the  "  pots,"  the  bottoms  of  which  are  nearly  level 
with  the  ground,  so  that  the  burs  of  iron  do  not  need  lifting  so  high  when  charging  them 
into  the  iurnace.  The  flame  rises  between  the  two  "  pots ;"  it  passes  also  below  and  around 
them,  through  the  horizontal  and  vertical  flues,  </,  and  issues  from  the  furnace  through  the 
six  small  chimneys,  n,  into  a  large  conical  space  which  is  built  around  the  whole  furnace, 
80  to  40  feet  high,  open  at  the  top.     This  cone  increases  the  draft  of  the  furnace,  and  car- 

„.  ries  away  the  smoke.     There  are  three 

■^  openings  in  the  front  of  the  arch  ;  two, 

T,  fifj.  (319,  above  the  pots,  serve  to  ad- 
mit and  remove  the  bars  ;  they  are  about 
8  inches  square  ;  in  each  a  piece  of  iron 
is  placed  upon  which  the  bars  slide  in 
and  out  of  the  furnace.  The  workman 
enters  by  the  middle  opening,  p,  to 
arrange  the  bars,  which  he  lays  flat  in 
the  pots,  and  spreads  a  layer  of  char- 
coal, ground  small,  between  each  layer ; 
the  bars  are  laid  near  each  other,  ex- 
cepting those  next  to  the  side  of  the 
pot,  which  are  placed  an  inch  from  it ; 
the  last  stratum  of  iron  is  covered  with 
a  thick  layer  of  charcoal,  and  the  whole 
is  carefully  covered  with  loamy  earth  4  to  5  inches  thick.  The  iron  is  gradually  heated,  in 
about  4  days  has  become  fully  heated  through,  and  the  furnace  has  then  attained  its  maxi- 
mum heat,  which  is  maintained  for  2  or  3  days  until  the  first  test  bar  is  drawn  out ;  the  heat 
is  afterward  regulated,  according  to  the  degree  of  hardness  which  may  be  required.  The 
iron  is  converted  in  8  days  if  for  soft  steel,  and  in  9  to  1 1  days  if  for  harder  purposes. 

Conversion  usually  commences  in  60  to  70  hours  after  the  furnace  is  lighted.  The  pores 
of  the  iron  being  opened  by  heat,  the  carbon  is  gradually  absorbed  by  the  mass  of  the  bar, 
but  the  carbonization  or  conversion  is  effected,  as  it  were,  in  layers.  To  explain  the  the- 
ory in  the  clearest  manner,  suppose  a  bar  to  be  composed  of  a  number  of  lamina; — the 
combination  of  the  carbon  with  the  iron  is  first  effected  on  the  surface,  and  gradually  ex- 
tends from  one  lamina  to  another,  until  the  whole  is  carbonized.  To  effect  this  complete 
carbonization  the  iron  requires  to  be  kept  at  a  considerable  uniform  heat  for  a  length  of 
time.  Thin  bars  of  iron  are  much  sooner  converted  than  thick  ones.  Reaumur  states,  in 
his  experiments,  that  if  a  bar  of  iron  7ig  of  an  inch  thick  is  converted  in  6  hours,  a  bar 
Vio  of  an  inch  would  require  36  hours  to  attain  the  same  degree  of  hardness.  The  carbon 
introduces  itself  successive/y :  the  first  lamina  or  surface  of  a  bar,  combining  with  a  portion 
of  the  carbon  with  which  it  is  in  contact,  gives  a  portion  of  the  carbon  to  the  second  lam- 
ina, at  the  same  time  taking  up  a  fresh  quantity  of  carbon  from  the  charcoal ;  these  succes- 
sive combinations  are  continued  until  the  whole  thickness  is  converted  ;  from  which  theory 
it  is  evident  that  from  the  exterior  to  the  centre  the  dose  of  carbon  becomes  proportionately 
less.  Steel  so  produced  cannot  be  said  to  be  perfect ;  it  possesses  in  some  degree  the  de- 
fect of  natural  steel,  being  more  carbonized  on  the  surface  than  at  the  centre  of  the  bar. 
From  this  theory  we  perceive  that  steel  made  by  cementation  is  different  in  its  character 
from  that  produced  directly  from  crude  metal.  In  conversion  the  carbon  is'  made  succes- 
sively to  penetrate  to  the  centre  of  the  bar,  whilst  in  the  production  of  natural  steel,  the 
molecules  of  metal  which  compose  the  mass  are  jjer  se  charged  with  a  certain  percentnge 
of  carbon  necessary  for  their  steelification  ;  not  imbibed,  but  obtained  by  the  decarboniza- 
tion  of  the  crude  iron  down  to  a  point  requisite  to  produce  steel. 

During  the  process  of  cementation,  the  introduction  of  the  carbon  disintegrates  the 
molecules  of  the  metal,  and  in  the  harder  steel  produces  a  distinct  crvstallization  of  a  white 
silvery  color.  Wherever  the  iron  is  unsound  or  imperfectly  manufactured,  the  surface  of 
the  steel  becomes  covered  with  blisters  thrown  up  by  the  dilation  of  the  metal  and  intro- 
duction of  carbon  between  those  laminjp  which  are  imperfectly  welded.  Reaumur  and  others 
have  attributed  this  phenomenon  to  the  presence  of  sulphur,  various  salts,  or  zinc,  which 
dilate  the  metal  ;  but  this  is  incorrect,  because  we  find  that  a  bar  of  cast  steel  which  is 
homogeneous  and  perfectly  free  from  internal  imperfections  never  blisters,  for  although  it 
receives  the  highest  dose  of  carbon  in  the  furnace,  yet  the  surface  is  perfectly  smooth. 
From  this  it  is  evident  that  the  blisters  are  occasioned  by  imperfections  in  the  iron.     Iron 


STEEL. 


1003 


increases,  both  in  length  and  weight,  during  conversion.     Hard  iron  increases  less  than  soft. 
The  augmentation  in  weight  may  be  said  to  be  '/200,  and  in  length  V120,  on  an  average. 

The  operation  ot"  conversion  is  extremely  simple  in  its  manipulation ;  nevertheless,  it 
requires  great  care,  and  a  long  as  well  as  a  varied  experience,  to  enable  a  manager  to  pro- 
duce every  kind  or  temper  required  by  consumers.  Considerable  knowledge  is  required  to 
ascertain  the  nature  of  the  irons  to  be  converted,  because  all  irons  do  not  convert  equally 
well  under  the  same  circumstances ;  some  require  a  diliercnt  treatment  from  others,  and, 
again,  one  iron  may  require  to  be  converted  at  a  different  degree  of  heat  from  another.  The 
furnace  must  have  continual  care,  and  be  kept  air-tight,  so  that  the  steel,  when  carbonized, 
may  not  again  become  oxidized.  It  is  known  amongst  steel-makers,  that  if  iron  be  brought 
in  contact  with  carbon,  and  if  heat  be  applied,  it  will  become  steel.  This  is  the  knowledge 
gleaned  up  by  workmen,  and  also  by  too  many  owners  of  converting  furnaces.  The  incon- 
venience arising  from  a  want  of  care  and  knowledge  of  the  peculiar  state  of  the  iron  during 
its  conversion,  sometimes  occasions  great  disappointment  and  loss.  The  success  usually 
attained  by  workmen  may,  however,  be  attributable  to  an  every-day  attention  to  one  object, 
thus  gaining  their  knowledge  from  experience  alone.  The  conversion  or  carbonization  of 
the  iron  is  the  foundation  of  steel-making,  and,  as  such,  may  be  considered  as  the  first  step 
in  its  manufacture.  Before  bar  steel  is  used  for  manufiicturing  purposes,  it  has  to  be  heated, 
and  hammered  or  rolled.  Its  principal  uses  are  for  files,  agricultural  implements,  spades, 
shovels,  wire,  &c.,  and  in  very  large  quantities  for  coach  springs. 

Bar  steel  is  also  used  for  manufacturing  shear  steel.  It  is  heated,  drawn  to  lengths  3 
feet  long,  then  subjected  to  a  welding  heat,  and  some  six  or  eight  bars  are  welded  together, 
precisely  as  described  in  the  refinement  of* natural  steel;  this  is  called  single  shear.  It  is 
further  refined  by  doubling  the  bar,  and  submitting  it  to  a  second  welding  and  hammering ; 
the  result  is  a  clearer  and  more  homogeneous  steel.  During  the  last  seven  years  the  manu- 
facture of  this  steel  has  been  limited,  mechanics  preferring  a  soft  cast  steel,  which  is  much 
superior,  wlien  properly  manufactured,  and  which  can  be  very  easily  welded  to  iron. 

The  price  of  bar  steel  varies  according  to  the  price  of  the  iron  from  which  it  is  made; 
but,  as  a  general  average,  its  price  in  commerce  may  be  taken  at  £5  per  ton  beyond  the 
price  of  the  iron  from  which  it  is  made.  Bar  steel  produced  from  the  better  irons  is 
usually  dearer  than  the  commoner  kind,  on  account  of  their  scarcity. 

Shear  steel  in  ordinary  size  sells  at  £60  per  ton  net. 

Coach-spring  steel  from  foreign  iron,  £22        " 

Coach-spring  steel  from  English  iron,  £18        " 

These  may  be  taken  as  approximate  prices  in  1859-'60. 

Both  natural,  puddled,  and  converted  steel  have  great  defects  in  temper,  clearness,  and 
uniformity,  and  are  unfit  for  most  useful  purposes.  To  obviate  these  defects,  these  steels 
are  broken  in  pieces  and  melted  in  a  crucible,  thus  freeing  them  from  any  deleterious  mat- 
ter they  might  contain  ;  equality  in  texture  and  degree  of  hardness  is  thus  obtained,  whilst 
the  steel  is  also  capable  of  receiving  a  clear  and  beautiful  polish. 

The  process  of  melting  bar 
steel,  and  tlius  producing  east  f~"^ '  1^1^ 
steel,  was  first  practically  car- 
ried on  by  Mr.  Huntsman,  of 
Atterclifle ;  the  process  itself  is 
very  simple.  Fir/.  620  shows 
a  cross  section  of  the  furnace 
universally  used. 

The  furnace  a  is  square, 
lined  with  fire-stone  12  inches 
by  22  wide,  and  36  inches  deep 
from  the  grate  bar  to  the  under 
side  of  the  cover  b.  c  is  a 
crucible,  of  which  two  are 
placed  in  one  "  melting  hole." 
D  is  the  flue  in'o  the  chimney 
E,  wliich  is  about  40  feet  high, 
lined  with  fire-brick.  There  is 
an  air  flue  which  is  used  to 
regulate  the  draught  at  p.  g 
is  the  ash  pit,  and  11  the  cellar, 
which  is  arclied  over. 

The  steel  is  broken  in  pieces 
and  charged  into  the  crucible, 
whicli    is    placc^d    on    a   stand 
and  provided  with  a  cover ;  coke  is  used  as  a  fuel,  and  an  intense  heat  is  obtained.     The 
crucible  is  charged  three  times  during  the  day,  and  is  then  burnt  through  ;  the  first  charge 


1004 


STEEL. 


is  usually  36  lbs.,  which  requires  from  three  to  four  hours  to  melt  it ;  the  second  charge  is 
about  32  lb.*.,  which  is  melted  in  about  three  hours ;  the  last  charge  is  '2S  to  '60  Ibk,  which 
does  not  recjuire  more  than  two  to  two  and  a  half  hours  to  become  perl'ectly  melted.  The 
coi!sum[)tion  of  coke  averages  3|  tons  per  ton  of  cast  steel.  \Vhen  the  steel  is  completely 
fluid,  tl.e  crucible  is  drawn  from  the  furnace,  and  the  steel  poured  into  a  cast-iron  niould ; 
the  result  is  an  ingot,  which  is  subsequently  rolled  or  hammered,  according  to  the  want  of 
the  consumer. 

Although  the  melting  of  cast  steel  is  a  simple  process,  yet,  on  the  other  hand,  the  manu- 
facture of  cast  steel  suitable  for  the  various  ua7tts  of  those  who  consume  it  requires  an  ex- 
tensive knowledge  ;  a  person  who  is  capable  of  successfully  conducting  a  Uianufactory,  must 
make  himself  master  of  the  treatment  to  which  the  steel  in  manufactures  will  be  submitted 
by  every  person  who  consumes  it.  Cast  steel  is  not  only  made  of  many  degrees  of  hard- 
ness, but  it  is  also  made  of  different  qualities  ;  a  steel-maker  has,  therefore,  to  conibine  a 
very  intimate  knowledge  of  the  exact  intrinsic  quality  of  the  iron  he  uses,  or  that  produced 
by  a  mixture  of  two  or  three  kinds  together ;  he  has  to  secure  as  compicte  and  as  equal  a 
degree  of  carbonization  as  possible,  which  can  only  be  attained  by  possessing  a  perfect  prac- 
tical and  theoretical  knowledge  of  the  process  of  converting  ;  he  has  to  know  that  the  steel 
he  uses  is  ecjual  in  hardness,  in  which,  without  much  practice,  he  n.ay  easily  be  deceived  ; 
he  mu.st  give  his  own  instructions  for  its  being  carefully  melted,  and  he  must  examine  its 
fracture  by  breaking  off  the  end  of  each  ingot,  and  exercise  his  judgment  whether  or  not 
proper  care  has  been  taken  ;  besides  all  this  knowledge  and  care,  a  steel-niaker  has  to  adapt 
.  the  capabilities  of  bis  steel  to  the  vants  and  rtquiriiiictii&  of  the  consumer.  There  are  a 
vast  variety  of  defects  in  steel  as  usually  manufactured  ;  >)ut  there  are  a  f;ir  gi  eater  nun.ber 
of  instances  in  which  steel  is  not  adapted  for  the  njanufacture  of  the  article  for  which  it  was 
expressly  made.  Cast  steel  may  be  manufactured  lor  planir.g,  borirg,  or  turning  tools;  its 
delects  may  be,  that  the  tools,  when  made,  ciack  in  the  process  of  hardening,  or  that  the 
tool,  whilst  exceedingly  strong  in  one  pait,  will  be  found  in  ar.other  part  utterly  useless. 

Cast  steel  may  be  wanted  for  the  engraver.  It  niay  be  produced  apparently  perfect,  and 
with  a  clear  surface,  but  may  be  so  improperly  manufactured,  that  when  the  plate  has  been 
engraved  and  has  to  be  hardened,  it  is  found  covered  with  soft  places.  The  trial  is  even 
greater  when  the  engraving  is  transferred  by  pressure  to  another  plate.  It  is,  therefore, 
evident  that  a  steel-maker  must  not  only  attend  to  the  intrinsic  quality  of  his  steel,  but  he 
has  to  use  his  judgment  as  regards  the  degree  of  hardness  and  tenacity  which  it  should  pos- 
sess, so  as  to  iidapt  it  to  the  peculiar  requisites  <f  its  e/hjiloiitiurd. 

The  manufacture  of  cast  steel  is  open  to  great  ten.ptations,  which  n^ay  he  termed  fraud- 
ulent. Swedish  iron,  as  I  have  already  stated,  varies  in  price  accordii.g  to  its  usefulness  for 
steel  purposes  ;  cast  steel  may,  therefore,  be  manufactured  from  a  metal  sellirg  at  £20  per 
ton,  whilst  the  price  charged  for  it  to  the  consumer  presumes  it  to  have  been  made  from  a 
metal  worth  £30  per  ton.  Tlie  exterior  of  the  bar  is  perfect,  the  fracture  appears  to  the 
eye  satisfactory,  and  its  intrinsic  value  is  only  discovered  when  it  is  put  to  tl.e  test ;  thus, 
whilst  a  steel-maker  has  to  exercise  his  knowledge,  judgment,  and  care,  he  has  a  moral  duty 
to  perform,  by  giving  to  his  customer  a  metal  of  the  intrinsic  value  he  professes  it  to  be, 
and  for  which  he  makes  his  charge. 

In  manuHicturing  the  commoner  description  of  steel,  particularly  cast  steel  made  from 
English  iron,  black  oxide  of  manganese  is  added  to  the  steel  in  the  crucible,  and  acts  as  a 
detergent.  The  oxygen  unites  with  a  portion  of  the  carbon  in  the  steel,  formirg  carbonic 
oxide  gas,  which  acts  upon  the  imperfectly  metallic  portions  of  the  steel  used,  and  liberates 
the  metal,  whilst  the  deleterious  matter  is  taken  up  and  forms  a  sli.g  with  the  manganese. 
There  has  been  a  great  controversy  regarding  the  invention  which  originated  with  Mr.  Heath. 
This  substance  is  not  generally  used  wlien  the  Dannemora  irons  are  melted,  as  they  are  very 
pure,  and  the  addition  of  an  oxide  partially  destroys  the  temper  of  the  steel.  The  Indian 
steel,  or  wootz,  is  also  a  cast  steel. 

Indian  steel,  cr  xeootz. — The  wootz  ore  consists  of  the  magnetic  oxide  of  iron,  united 
with  quartz,  in  proportions  which  do  not  .«eem  to  differ  much,  I'cirg  generally  about  42  of 
quartz  and  58  of  magnetic  oxide.  Its  grains  are  of  various  sizes,  down  to  a  sandy  texture. 
The  natives  prepare  it  for  smelting  by  pounding  the  ore,  and  winnowirg  away  tl  e  stony 
matrix,  a  task  at  which  the  Hindoo  females  are  very  dexterous.  The  manner  in  which  iron 
ore  is  smelted  and  converted  into  wootz  or  Indian  steel,  by  the  native  s  at  the  present  day, 
is  probably  the  very  same  that  was  practised  by  them  at  the  time  of  the  invasion  of  Alex- 
ander ;  and  it  is  a  uniform  process,  from  the  Himalaya  moimtains  to  Cape  Comorin.  Tl.e 
furnace  or  bloomery  in  which  the  ore  is  smelted  is  from  4  to  5  feet  high  ;  it  is  somewhat 
pear-shaped,  being  about  2  feet  wide  at  bottom,  and  1  foot  at  top ;  it  is  built  entirely  of 
clay,  so  tliat  a  coujile  of  men  can  finish  its  erection  in  a  few  hours,  and  have  it  ready  for 
use  the  next  day.  There  is  an  opening  in  front  about  a  foot  or  more  in  height,  which  is 
built  up  with  clay  at  the  commencement,  and  broken  down  at  the  end  of  each  smelting 
operation.  The  bellows  are  usually  made  of  a  goat's  skin,  which  has  l)een  stripped  from 
the  animal  without  ripping  open  the  part  covering  the  belly.     The  apertures  at  the  legs  arc 


STEEL. 


1005 


tied  up,  and  a  nozzle  of  bamboo  is  fastened  in  the  opening  formed  by  the  neck.  The  ori- 
fice of  the  tail  ii  enlarged  and  distended  by  two  slips  of  bamboo.  These  are  grasped  in  the 
hand,  and  kept  close  together  in  making  the  stroke  for  the  blast ;  in  the  returning  stroke 
they  are  separated  to  admit  the  air.  By  working  a  bellows  of  this  kind  witli  each  hand, 
making  alternate  strokes,  a  pretty  uniform  blast  is  produced.  The  bamboo  nozzles  of  the 
bellows  are  inserted  into  tubes  of  clay,  which  pass  into  the  furnace  at  the  bottom  corners 
of  the  temporary  wall  in  front.  The  furnace  is  tilled  with  charcoal,  and  a  lighted  coal  being 
introduced  before  the  nozzles,  the  mass  in  the  interior  is  soon  kindled.  As  soon  as  this  is 
accomplished,  a  small  portion  of  the  ore,  previously  moistened  with  water,  to  prevent  it 
from  running  through  the  charcoal,  but  without  any  tlux  whatever,  is  laid  on  the  top  of  the 
coals,  and  covered  with  charcoal  to  lill  up  the  furnace. 

In  this  manner  ore  and  fuel  are  supplied ;  and  the  bellows  are  urged  for  3  or  4  hours, 
when  the  process  is  stopped  ;  and  the  temporary  wall  in  front  being  broken  down,  the  bloom 
is  removed  by  a  pair  of  tongs  from  the  bottom  of  the  fumace.  It  is  then  beaten  with  a 
wooden  mallet,  to  separate  as  nmch  of  the  scoriic  as  possible  from  it,  and,  while  still  red  hot, 
it  is  cut  through  the  middle,  but  not  separated,  in  order  merely  to  show  the  quality  of  the 
interior  of  the  mass.  In  this  state  it  is  sold  to  the  blacksmiths,  who  make  it  into  bar  iron. 
The  proportion  of  such  iron  made  by  the  natives  from  100  parts  of  ore  is  about  15  parts. 
In  converting  the  iron  into  steel,  the  natives  cut  it  into  pieces,  to  enable  it  to  pack  belter 
in  the  crucible,  which  is  formed  of  refractory  clay,  mixed  with  a  large  quantity  of  charred 
husk  of  rice.  It  is  seldom  charged  with  more  than  a  pound  of  iron,  which  is  put  in  with  a 
proper  weight  of  dried  wood  chopped  small,  and  both  are  covered  with  one  or  two  green  ^ 
leaves;  the  proportions  being  in  general  10  parts  of  iron  to  1  of  wood  and  leaves.  The 
mouth  of  the  crucible  is  then  stopped  with  a  handful  of  tempered  clay,  rammed  in  very 
closely  to  exclude  the  air.  The  wood  preferred  is  the  Casxia  auriculata,  and  the  leaf  that 
of  the  Asdepias  cfiganfea,  or  the  Coavolvulus  laurifolius.  As  soon  as  the  clay  plugs  of  the 
crucible  are  dry,  from  twentj'  to  twenty-four  of  them  are  built  up  in  the  form  of  an  arch,  in 
a  small  blast  furnace  ;  they  arc  kept  covered  with  charcoal,  and  subjected  to  heat  urged  by 
a  blast  for  about  two  hours  and  a  half,  when  the  process  is  considered  to  be  complete.  The 
crucibles,  being  now  taken  out  of  the  furnace  and  allowed  to  cool,  are  broken,  and  the  steel 
is  found  in  the  form  of  a  cake,  rounded  by  the  bottom  of  a  crucible.  "When  the  fusion  has 
been  perfect,  the  top  of  the  cake  is  covered  with  stri;e,  radiating  from  the  centre,  and  is 
free  from  holes  and  rough  projections;  but  if  the  fusion  has  been  imperfect,  the  surface  of 
the  cake  has  a  honeycomb  appearance,  with  projecting  lumps  of  malleable  iron.  On  an 
average,  four  or  five  cakes  are  more  or  less  defective.  These  imperfections  have  been  tried 
to  be  corrected  in  London  by  remelting  the  cakes,  and  running  them  into  ingots ;  but  it  is 
obvious  that  when  the  cakes  consist  partially  of  malleable  iron  and  of  unreduced  oxide, 
simple  fusion  caimot  convert  them  into  good  steel.  When  care  is  taken,  however,  to  select 
only  such  cakes  as  are  perfect,  to  remelt  them  thoroughly,  and  tilt  them  carefully  into  rods, 
an  article  has  been  produced  which  possesses  all  the  requisites  of  fine  steel  in  an  eminent 
degree.  In  the  Supplement  to  the  Encyclopaedia  Britannica,  article  Cutlery,  the  late  Mr. 
Stoddart,  of  the  Strand,  a  very  competent  judge,  has  declared,  "  that  for  the  purposes  of 
fine  cutlery,  it  is  infinitely  superior  to  the  best  English  cast  steel." 

The  natives  prepare  the  cakes  for  being  drawn  into  bars  by  annealing  them  for  several 
hours  in  a  small  charcoal  furnace,  actuated  by  bellows  ;  the  current  of  air  being  made  to  play 
upon  the  cakes  while  turned  over  before  it ;  whereby  a  portion  of  the  combined  carbon  is 
l)robably  dissipated,  and  the  steel  is  softened ;  without  which  operation  the  cakes  would 
break  in  the  attempt  to  draw  them.  They  are  drawn  by  a  hammer  of  a  few  pounds 
weight. 

Fig.  621  represents  the  mould  for  making  the  crucibles:  each  manufactm^r  makes  his 
own ;  M,  M,  is  a  solid  block  of  wood  let  into  the  floor,  having  a 
hole  which  admits  a  round  piece  of  iron  fixed  in  the  centre  of 
the  plug  p.  The  material  of  which  the  crucible  is  made  consists 
of  22  lbs.  of  fire-clay  got  from  Stannington  near  Sheffield,  from 
the  neighborhood  of  Burton-on-Trent,  or  Stourl)ridge  ;  2  lbs.  of 
t'le  old  crucible  after  it  has  been  used,  ground  to  powder,  and 
about  I  lb.  of  ground  coke.  These  quantities  are  sufficient  for 
one  crucible  of  the  ordinary  size.  This  composition  is  trodden 
for  8  or  10  hours  on  a  metal  floor ;  it  is  then  cut  into  pieces  of 
2(5  to  28  lbs.  ;  each  piece  is  rolled  round  nearly  to  the  size  of  the 
mould  into  which  it  is  introduced,  and  the  plug  p  is  driven  down 
with  a  mallet;  the  mould  is  furnished  with  a  movaltlc  bottoni^ 
when  the  pot  is  made,  the  mould  is  lifted  »ip  by  the  two  handles, 
and  fixhig  the  bottom  on  a  ]iost,  the  mould  fails,  and  leaves  the 
crucible  upon  it.  Converted  l)ars,  and  also  cast  steel  in  ingots, 
arc  reduced  to  bars,  rods,  and  sheets  by  hanmicring  or  rolling; 
when  forged,  they  arc  heated  in  a  small  fm-nace  urged  by  blast, 
an  1  drawn  to  bars  under  hammers  of  7  to  i)  cwt.,  giving  100  to  120  strokes  ji 


1006 


STEEL. 


"When  email  rods  are  required,  they  are  "  tilted,"  that  is,  they  are  heated  and  drawn 
under  hammers  of  3  or  4  cwt.,  striking  200  to  250  blows  per  minute.  When  steel  is  rolled, 
the  machinery  used  is  of  Uie  same  construction  as  that  required  lor  rolling  iron,  excepting 
that  the  rollers  are  usually  hard  on  the  surface.  Hardening  and  tempering  steel  is  a  deli- 
cate operation ;  small  articles  of  cutlery  are  usually  hardened  by  first  heating  them  to  a  red 
heat  and  plunging  them  in  water  ;  saws  and  such  articles  are,  when  heated,  plunged  into 
oil.  All  articles  are  tempered  by  carefully  heating  them  when  hardened,  and  the  degree  of 
temper  is  indicated  by  a  change  in  the  color  of  the  surface,  which  is  first  straw-colored,  then 
blue,  and  deep  blue :  color  is  thus  made  the  most  delicate  test  for  the  degree  of  temper 
given  :  after  this  operiition  steel  is  found  to  expand  a  little.  Alloys  of  steel  have  been  very 
carefully  made  by  Messrs.  Stoddart  &  Faraday,  but  no  alloy  has  at  present  been  found  to 
give  any  addition  to  the  intrinsic  quality  of  steel ;  the  empiric  titles  of  "  silver  steel," 
"  meteoric  steel,"  &c.,  may  be  regarded  simply  as  fanciful  names  to  recommend  the  article, 
either  as  a  raw  material  or  in  a  manufactured  state. 

Those  articles  called  "run  steel"  are  made  by  melting  pig-iron  and  pouring  it  into 
moulds  of  sand  in  which  the  required  article  has  been  moulded  ;  they  are  then  packed  in 
round  iron  pots  about  12  inches  diameter,  and  16  to  18  inches  high,  along  with  haematite 
iron  ore  crushed  to  powder ;  these  pots  are  packed  in  a  furnace,  and  heat  is  applied  from 
24  hours  to  several  days  ;  the  oxygen  abstracts  the  carbon  from  the  metal  of  which  the  arti- 
cles are  made,  and  they  become  to  a  certain  extent  malleable — so  much  so,  (hat  pieces  a 
quarter  of  an  inch  thick  may  be  bent  almost  double,  and  can  be  drawn  out  imder  a  ham- 
**mcr.  Forks,  table  knives,  scissors,  and  many  other  cheap  articles  are  so  made:  also  a  vast 
variety  of  parts  of  cotton  and  flax  machinery  are  so  manufactured,  especially  those  parts 
which  are  difficult  to  forge. 

"  Damascus"  or  Damasked  "  steel,"  is  made  by  melting  together  iron  and  steel,  or  bars 
of  steel  of  high  and  low  degrees  of  carbonization  ;  it  may  also  be  produced  by  melting 
hard  and  soft  steel  in  separate  crucibles,  mixing  th(jpi  together  whilst  fluid,  and  immediately 
pouring  the  mixture  into  an  ingot  mould  ;  the  damask  is  shown  by  the  application  of  dilute 
acid  to  the  surface  when  brightened.  The  analysis  of  a  genuine  Damascus  sword-blade  nas 
shown  that  it  is  not  a  homogeneous  steel,  but  a  mixture  of  steel  and  iron. 

During  the  past  few  years  a  great  many  processes  have  been  patented  with  a  view  of 
reducing  the  cost  of  east  steel ;  Mr.  Bessemer,  Mr.  Martieu,  Mr.  Mushet,  and  several  others, 
have  suggested  modes  of  producing  a  serviceable  steel  from  the  common  pig-iron.  A  full 
description  of  these  proposed  improvements  wouW  take  up  too  much  space,  but  can  be  ex- 
.iniincd  in  the  "Repertory  of  Arts:"  the  whole  of  these  processes  are  purposely  omitted, 
because  a  description  of  them  would  necessarily  demand  some  examination  of  their  merits. 

Statistical  account  of  the  viaimfactxirc  of  steel. — The  manufacture  of  .steel  in  England 
is  chiefly  confined  to  Sheffield,  although  it  is  also  made  at  Newcastle  and  in  Staffordshire. 
The  importation  of  Swedish  iron,  combined  with  that  furnished  from  English  materials, 
amounts  to  from  40,000  to  50,000  tons  per  annum  ;  of  course  this  weight  represents  the 
quantity  of  steel  manufactured  of  every  description. 

The  number  of  furnaces  in  Sheffield  iind  its  neighborhood  are  as  follows: — 

Cast  steel  Furnaces, 
Converting  Furnaces.  or  holes. 

1835 "56 554 

1842 97 774 

1846 105 974 

1853 160         -         -         -         -         -      1,495 

A  converting  furnace  will  produce  300  tons  of  steel  per  annum,  but  if  each  produce  250 
tons,  160  converting  furnaces  would  represent  a  make  of  40,000  tons  of  steel  a  year  in 
Sheffield  alone.  Again,  there  are  1,495  melting  holes;  each  furnace  of  10  holes  will  melt 
200  tons ;  this,  therefore,  shows  a  product  annually  of  29,900  tons ;  but  as  such  furnaces 
may  not  all  be  in  continual  work  from  various  causes,  the  quantity  of  cast  steel  manufac- 
tured in  Sheffield  may  be  estimated  at  23,000  tons — the  weight  of  coach-spring  steel,  esti- 
mated at  10,000  tons,  leaving  a  remainder  of  7,000  tons  of  bar  for  the  manufacture  of  Ger- 
man, faggot,  single  and  double  shear  steel.  As  regards  the  price,  I  take  cast  steel  at  £45 
per  ton  ;  its  commercial  value  varies  from  .£35  to  .£60  per  ton  net,  and  as  a  large  quantity 
of  the  cheaper  steel  is  sold,  £45  per  ton  is  an  average.  The  price  of  bar  steel  is  below  the 
ri'nl  value,  since  it  includes  all  shear  steel,  the  best  of  which  sells  at  £60  per  ton,  whilst, 
however,  a  portion  of  this  7,000  tons  sells  only  at  £28,  and  some  even  lower.  The  price 
of  coach  springs  is  the  price,  now  paid  for  them. 

The  statistics  of  this  metal  give  the  following  results : — 

France  produces       ...         14,954  tons,  average  value  of   £443,85Q 

Prussia 5,453     "  "  170,824 

Austria 13,037     "  "  321,073 

United  States  ....         10,000     "  "  212,500 

England 40,000     "  "  1,470,000 


STEEL. 


1007 


Such  is  the  contrast  of  the  manufacturing  power  of  the  steel-producing  countries ;  it 
shows  the  eminent  position  of  England,  in  both  weight  and  value  ;  this  can  only  arise  from 
the  practical  skill  and  scientific  knowledge  which  we  have  brought  to  bear  upon  its  manu- 
facture, and  the  active  energy  which  has  enabled  us  to  produce  steel  suitable  for  every  pur- 
pose in  the  arts.  This  superiority  not  only  enables  our  manufacturers  to  maintain  the  high 
position  they  now  hold,  but  to  increase  it  yet  further  ;  for  we  daily  see  our  production  ex- 
panding, not  only  to  supply  the  wants  of  our  home  manufacturers,  but  also  Ibr  the  conti- 
nent of  Europe,  as  well  as  the  United  States  of  America  and  Canada. 

Besftemcr's  malleable  Iron  and  Steel. — In  the  article  "  Ikon"  will  be  found  a  statement 
of  the  process  proposed  by  Mr.  Bessemer  for  converting  crude  pig-iron  into  malleable  iron, 
<vhich  we  believe  to  be  a  fair  representation  of  all  the  facts  up  to  the  period  when  that 
paper  was  written.  Since  then  the  process  has  been  tried  in  the  manufacture  of  steel,  and, 
certainly,  it  appears,  with  much  more  success  than  attended  the  early  experiments  made  on 
iron.  For  the  purpose  of  placing  the  matter,  however,  clearly  before  our  readers,  we  ex- 
tract a  considerable  portion  of  Mr.  Henry  Bessemer's  paper  "  On  the  manufacture  of  malle- 
able Iron  and  Steel,"  read  before  the  Institution  of  Civil  Engineers  in  May  last. 

"  The  want  of  success  which  attended  some  of  the  early  experiments  was  erroneously 
attributed,  by  some  persons,  to  the  '  burning '  of  the  metal,  and  by  others,  to  the  absence 
of  cinder,  and  to  the  crystalline  condition  of  cast  metal.  It  was  almost  needless  to  say, 
that  neither  of  the  causes  assigned  had  any  thing  to  do  with  the  failure  of  the  process,  in 
those  cases  wliere  failure  had  occurred.  Chemical  investigation  soon  pointed  out  the  real 
source  of  difficulty.  It  was  found,  that  although  the  metal  could  be  wholly  decarbonized, 
and  the  silicum  be  removed,  the  quantity  of  sulphur  and  of  phosphorus  was  but  little 
affected  •,  and  as  different  samples  were  carefully  analyzed,  it  was  ascertained  that  red- 
shortness  was  always  produced  by  sulphur,  when  present  to  the  extent  of  one-tenth  per  cent., 
and  that  cold-shortness  resulted  from  the  presence  of  a  like  quantity  of  phosphorus ;  it 
therefore  became  necessary  to  remove  those  substances.  Steam  and  pure  hydrogen  gas 
were  tried,  with  more  or  less  success,  in  tlie  removal  of  sulphur,  and  various  fluxes,  com- 
posed chiefly  of  silicates  of  the  oxide  of  iron  and  manganese,  were  brought  in  contact  with 
the  fluid  metal  during  the  process,  and  the  quantity  of  phosphorus  was  thereby  reduced. 
Thus,  m my  months  were  consumed  in  laborious  and  expensive  experiments ;  consecutive 
steps  in  advance  were  made,  and  many  valuable  facts  were  elicited.  The  successful  work- 
ing of  some  of  the  higher  qualities  of  pig-iron  caused  a  total  change  in  the  process,  to  which 
the  efforts  of  Messrs.  Bessemer  &  Longsdon  were  directed.  It  was  determined  to  import 
some  of  the  best  Swedish  pig-iron,  from  which  steel  of  excellent  quality  was  made,  and 
tried  for  almost  all  the  uses  for  which  steel  of  the  highest  class  was  employed.  It  was  then 
decided  to  discontinue,  for  a  time,  all  further  experiments,  and  to  erect  steel  works  at  Shef- 
field for  the  express  purpose  of  fully  developing  and  working  the  new  process  commer- 
cially, and  thus  to  remove  the  erroaeous  impressions  so  generally  entertained  in  reference 
to  the  Bessemer  process. 

"  In  manufacturing  tool  steel  of  the  highest  quality,  it  was  found  preferable,  for  several 
reasons,  to  use  the  best  Swedish  pig-iron,  and,  when  converted  into  steel  by  the  Bessemer 
process,  to  pour  the  fluid  steel  into  water,  and  afterward  to  remelt  the  shotted  metal  in  a 
crucible,  as  at  present  practised  in  making  blister-steel,  whereby  the  small  ingots  required 
for  this  particular  article  were  more  perfectly  and  more  readily  made. 

"  It  was  satisfaetory  to  know  that  there  existed  in  this  country  vast,  and  apparently  in- 
exhaustible, beds  of  the  purest  ores  fitted  for  the  process.  Of  the  hematite  alone,  970,000 
tons  were  raised  annually,  and  this  quantity  might  be  doul)led  or  trebled,  whenever  a  de- 
mand arose.  It  was  from  the  hematite  pig-iron  made  at  the  Workington  Iron  Works  tliat 
most  of  the  iron  and  steel  was  made.  Alx)ut  1  ton  13  cwts.  of  ore,  costing  lO.s.  per  ton, 
would  yield  1  ton  of  pig  metal,  with  GO  per  cent,  less  lime,  and  20  per  cent,  less  fuel,  than 
were  generally  consumed  when  working  inferior  ores ;  while  the  furnaces  using  this  ore 
alone  yielded  from  220  tons  to  240  tons  per  week,  instead  of,  say,  160  tons  to  180  tons  ])er 
week,  when  working  with  common  iron-stone.  The  Cleator  Moor,  the  Wcardale,  and  the 
Forest  of  Dean  Iron  Works  also  produced  an  excellent  metal  for  this  purpose. 

"  The  form  of  converting  vessel  which  had  l)een  found  most  suitable  somewhat  resem- 
bled the  glass  retort  used  by  chemists  for  distillation.  It  was  mounted  on  axes,  and  was 
lined  with  'ganister'  or  road  drift,  which  lasted  during  the  conversion  of  thirty  or  forly 
cliarges  of  Steel,  and  was  then  ((uickly  and  cheaply  repaired,  or  renewed.  Tli(>  vessel  w;is 
brouglit  into  an  inclined  position,  to  receive  the  charge  of  crude  iron,  dnri|g  which  time 
-the  tuyires  were  above  the  surface  of  the  metal.  As  soon  as  the  whole  cluirge  was  run  in, 
tlie  vessel  was  moved  on  its  axes,  so  as  to  bring  the  tuy6res  l)elow  the  level  of  the  metal, 
wlien  the  process  was  at  once  brought  into  full  activity,  and  twenty  small,  though  powerful, 
jets  of  air  sprang  upward  through  tlie  fluid  mass;  the  air,  expanding  in  volume,  divideil 
itself  iiito  glol)ules,  or  ))urst  violently  upward,  carrying  with  it  a  large  ((uantity  of  the  fluid 
metal,  which  again  fell  back  into  the  boiling  mass  below.  Tlie  oxygen  of  the  air  appeared, 
in  this  process,  first  to  produce  the  combustion  of  the  carbon  contained  in  the  iron,  and  at 


1008 


STEEL. 


the  same  time  to  oxidize  tlie  silicium,  producing  silicic  acid,  which,  uniting  with  the  oxide 
of  iron,  obtained  by  the  combustion  of  a  small  quantity  of  metallic  iron,  thus  produced  a 
fluid  silicate  of  the  oxide  of  iron,  or  '  cinder,'  which  was  retained  -in  the  vessel  and  assisted 
in  purifying  the  metal.  The  increase  of  temperature  which  the  metal  underwent,  and  which 
si'cuied  so  disproportionate  to  the  quantity  of  carbon  and  iron  consumed,  was  doubtless 
owing  to  the  i'avorable  circumstances  under  which  combustion  took  place.  There  was  no 
iutcivcpting  material  to  absorb  the  heat  generated,  and  to  jirevent  its  being  taken  up  by  the 
ii:ctal,  for  heat  was  evolved  at  thousands  of  points,  distributed  throughout  the  fluid,  and 
when  the  metal  boiled,  the  Avhole  mass  rose  I'ar  above  its  natuial  level,  iorming  a  sort  of 
spongy  froth,  with  an  intensely  vivid  combustion  going  on  in  every  one  of  its  numberless, 
ever-changing  cavities.  Thus,  by  the  mere  action  of  the  blast,  a  ten  perature  was  attained, 
in  the  largest  masses  of  metal,  in  ten  or  twelve  minutes,  that  whole  days  of  exposure  in  the 
most  powerful  furnace  would  fail  to  produce. 

"  The  amount  of  deearbonizatiou  of  the  metal  was  regulated,  with  great  accuracy,  by  a 
meter,  which  indicated  on  a  dial  the  number  of  cubic  icet  of  air  that  had  passed  through 
the  metal ;  so  that  steel  of  any  quality  or  temper  could  be  obtained  vith  the  greatest  cer- 
tainty. As  soon  as  the  metal  liad  reached  the  desired  point,  (as  indicated  by  the  dial,)  the 
workmen  moved  the  vessel,  so  as  to  pour  out  the  fluid  malleable  iron  or  steel  into  a  founder's 
ladle,  which  was  attached  to  the  arm  of  a  hydraulic  crane,  so  as  to  be  brought  readily  over 
the  moulds.  The  ladle  was  provided  with  a  flre-elay  plug  at  the  bottoni,  the  raising  of 
which,  by  a  suitable  lever,  allowed  the  fluid  metal  to  descend  in  a  clear  vertical  stream  into 
the  moulds.  When  the  first  mould  was  filled,  the  plug  valve  was  depressed,  and  the  metal 
was  prevented  from  flowing  until  the  easting  ladle  was  moved  over  the  next  mould,  when 
the  raising  of  the  plug  allowed  this  to  be  filled  in  a  similar  manner,  and  so  on  until  all  the 
moulds  were  filled. 

"  The  easting  of  large  masses  of  a  perfectly  homogeneous  malleable  metal  into  any  de- 
sired form  rendered  unnecessary  the  tedious,  expensive,  and  uncertain  operation  of  welding 
now  employed  wherever  large  masses  were  required.  The  extreme  toughness  and  extensi- 
bility of  the  Bessemer  iron  was  proved  by  the  bending  of  cold  bars  of  iron  3  in.  square, 
under  the  hammer,  into  a  close  fold,  without  the  smallest  perceptible  rupture  of  the  metal 
at  any  part;  the  bar  being  extended  on  the  outside  of  the  bend  from  12  in.  to  16f  in.,  and 
being  compressed  on  the  inside  from  12  in.  to  7^  in.,  making  a  difference  in  length  of  9^ 
in.,  between  what,  before  bending,  were  the  two  parallel  sides  of  a  bar  3  in.  square.  An 
iron  cable,  consisting  of  four  strands  of  round  iron  li  in.  diameter,  was  so  closely  twisted, 
while  cold,  as  to  cause  the  strands  at  the  point  of  contact  to  be  permanently  imbedded  in 
each  other.  Each  of  these  strands  had  elongated  12i  in.  in  a  length  of  4  ft.,  and  had  dimin- 
ished Vio  of  an  inch  in  diameter,  throughout  their  whole  length.  Steel  bars,  2  in.  square 
and  2  ft.  G  in.  in  length,  were  twisted  cold  into  a  spiral,  the  angles  of  which  were  about  45 
degrees  ;  and  some  round  steel  bars,  2  in.  in  diameter,  were  bent  cold  under  the  hammer, 
into  the  form  of  an  ordinary  horse-shoe  magnet,  the  outside  of  the  bend  measuring  5  in. 
more  than  the  inside. 

"  The  steel  and  iron  boiler  plates,  left  without  shearing,  and  with  their  ends  bent  over 
cold,  afforded  ample  evidence  of  the  extreme  tenacity  and  toughness  of  the  metal ;  while 
the  clear,  even  surface  of  railway  axles  and  pieces  of  malleable  iron  ordnance  were  examples 
of  the  perfect  freedom  from  cracks,  flaws,  or  hard  veins,  which  forn/S  so  distinguishing  a 
characteristic  of  the  new  metal.  The  tensile  strength  of  this  metal  was  not  less  reniaikable, 
as  the  several  samples  of  steel  tested  in  the  proving  machine  at  Woolwich  arsenal  bore, 
according  to  the  reports  of  Colonel  Eardley  Wilmot,  R.A.,  a  strain  varying  from  150,000  lbs. 
to  160, 9U0  lbs.  on  the  square  inch,  and  four  samples  of  iron  boiler  plate  from  68,314  lbs.  to 
73,100  lbs.  ;  while,  according  to  the  published  experiments  of  Mr.  W.  Fairbairn,  Stafibrd- 
shire  plates  bore  a  mean  strain  of  46,000  lbs. ;  and  Low  Moor  and  Bowling  plates  a  mean 
of  57,120  lbs.  per  square  inch. 

"  There  was  also  another  fact  of  great  importance  in  a  commercial  point  of  view.  In 
the  manufacture  of  plates  for  boilers  and  for  shipbuilding,  the  cost  of  production  increased 
considerably  with  the  increase  of  weight  in  the  plate ;  for  instance,  the  Low  Moor  Iron 
Company  demanded  £22  per  ton  for  plates  weighing  2i  cwt.  each  ;  but  if  the  weight  ex- 
ceeded 5  cwt.,  then  the  price  rose  from  £22  to  .£"'.7  per  ton.  Now  with  cast  ingots,  such  as 
the  one  exhibited  and  from  which  the  sample  plates  were  made,  it  was  less  troublesome,  less 
expensive,  and  less  wasteful  of  material,  to  make  j)lates  weighing  from  10  cwt.' to  20  cwt., 
than  to  produfle  smaller  ones ;  and  indeed  there  could  be  but  little  doubt  that  large  plates 
would  eventu  *ly  be  made  in  preference,  and  that  those  who  wanted  small  plates  would  have 
to  cut  them  from  the  large  ones.  A  moment's  reflection  would,  tlierefore,  show  the  great 
economy  of  the  new  process  in  this  respect ;  and  when  it  was  remembered  that  every 
riveted  joint  in  a  plate  reduced  the  ultimate  strength  of  each  100  lbs.  to  70  lbs.,  the  great 
value  of  long  plates  for  gir<lers  and  for  shipbuilding  would  be  fully  appreciated. 

"  It  would  be  interesting  to  those  who  were  watching  the  advancement  of  the  new  pro- 
cess, to  know  that  it  was  already  rapidly  extending  itself  over  Europe.     Th.c  firm  of  Daniel 


STONE,  ARTIFICIAL. 


1009 


Elfstrand  &  Co.,  of  Edsken,  who  were  the  pioneers  in  Sweden,  had  now  made  several  hun- 
dred tons  of  excellent  steel  by  the  Bessemer  process.  Another  large  manufactory  had  since 
been  started  in  their  immediate  neighborhood,  and  three  other  companies  were  also  making 
arrangements  to  use  the  process.  The  authorities  in  Sweden  had  fully  investigated  the 
whole  process,  and  had  pronounced  in  favor  of  it.  Large  steel  circular  saw-plates  were 
made  by  Mr.  Goranson,  of  Gcfle,  in  Sweden,  the  ingot  being  cast  direct  from  the  fluid  metal 
within  hfteen  minutes  of  its  leaving  the  blast  furnace.  lu  J'rance  the  process  had  been  for 
some  time  carried  on  by  the  old  established  firm  of  James  Jackson  &  Son,  at  their  steel 
works  near  Bordeaux.  This  firm  w;is  about  to  manufacture  puddled  steel  on  a  large  scale. 
They  had  already  got  a  puddling  furnace  erected  and  in  active  operation,  when  their  atten- 
tion was  directed  to  the  Bessemer  process,  the  apparatus  for  which  was  put  up  at  their  works 
last  year ;  and  they  were  now  extending  their  field  of  operations,  by  putting  up  more  pow- 
erful apparatus  at  tlie  blast  furnaces  in  the  Landes.  There  were  also  four  other  blast  fur- 
naces in  the  south  of  France  in  course  of  erection,  for  the  express  purpose  of  carrying  out 
the  new  process. 

"  The  irons  of  Algeria  and  Saxony  had  produced  steel  of  the  highest  quality. 

"  Belgium  was  not  much  behind  her  neighbors  ;  the  process  was  now  being  carried  into 
operation  at  Liege,  where  excellent  steel  had  been  made  from  the  native  coke  iron  ;  while 
in  Sardinia  preparations  were  also  being  made  for  working  the  system.  Professor  Midler, 
of  Vienna,  and  M.  Dumas,  from  Paris,  had  visited  Sweden,  to  inspect  and  report  on  the 
working  of  the  new  system  in  that  country. 

"  That  the  process  admitted  of  further  improvement,  and  of  a  vast  extension  beyond  its 
present  limits,  the  author  had  no  doubt ;  but  those  steps  in  advance  would,  he  imagined, 
result  chiefly  from  the  experience  gained  in  the  daily  commercial  working  of  the  process, 
and  would  most  probably  be  the  contributions  of  the  many  practical  men  who  might  be 
engaged  in  carrying  on  the  manufacture  of  iron  and  steel  by  this  system." 

The  following  information  is  of  interest : — 

Comparative  tensile  strength  of  various  kinds  of  Iron  and  Steel  in  lbs.  per  square  inch. 

lbs. 
Ordinary  cast  iron  (which  varies  considerably)  may 

be  taken  at 18,656         Templetou. 

Swedish  cast  iron  used  for  ordnance  ...        33,000        Woolwich  Arsenal. 

"  Bessemer  "  iron  in  its  cast,  unhammered  state,  mean 

of  5  trials 41,242  " 

Wroxight  Iron  Plates  ;  mean  breaking  weight  with,  and  across,  the  fbre. 

lbs. 

Yorkshire  plates ;  best 59,584  Fairbairn. 

"  ordinary      -----         54,656  " 

Derbyshire      "  " 45,136  " 

Shropshire       "  " 50,176  " 

Staffordshire  "  " 45,472  " 

Mean  of  4  trials  of  soft  iron  plates  made  by  the  "  Bes- 
semer process"        68,319  Woolwich  Arsenal. 

Boiler  plates,  made  of  very  soft  cast  steel,  (approach- 
ing in  quality  to  iron,)  made  by  the  "Bessemer 

process" 110,000  Trials  at  Manchester. 

Iron  bars,  hammered  or  rolled. 

♦  lbs. 

English  bar  iron 65,872        Tcmpleton. 

" 56,000         Rcnnic's  Table3. 

Swedish        " 72,000                "           " 

"             " 72,064         Tcmpleton. 

"  Bessemer  iron,"  mean  of  8  trials  -        -        .        -  72,643        Woolwich  Arsenal. 

"                maximum 82,110 

Cast  steel  made  by  the  "  Bessemer  process,"  in  its 

unhammered  state ;  mean  of  8  trials         -         -  63,022                         " 

Sheflield  cast  steel 130,000        Rennie's  Tables. 

Cast  steel,  made  by  "  Krupp"  of  Essex     -        -        -  127,320        Woolwich  Arsenal. 

"                  "Captain  Uchatius"  -         -         -  91,955 
'Cast  steel,  made  of  Nova  Scotia  iron  by  the  ordinary 

process 128,043 

"  Bessemer  steel,"  mean  of  7  trials          -        -        -  152,911 

"                maximum   -         -         -         -         -  102,970 

STONE,  ARTIFICIAL.     Mr.  Buckwell  proi)oses  the  following  plans  for  the  construc- 
tion of  artificial  stone.     Taking  fragments  of  stone  suflicieutly  large  to  go  freely  into  his 
Vol.  in.— 64 


1010 


STONE,  ARTIFICIAL. 


mould,  he  fills  up  the  interstices  with  stones  of  various  sizes,  and  then  pours  in  a  mixture 
of  chalk  and  Thames  mud  or  Mersey  mud  burnt  together.  This  cement  being  poured  into 
the  mould,  the  whole  is  rammed  together  by  falling  hammers,  aiid  as  the  mould  is  perforated 
the  water  is  forced  out,  and  the  resulting  stone  is  so  hard,  when  removed  from  the  mould, 
that  it  rings  when  struck.  It  will  be  evident  to  those  acquainted  with  hydraulic  mortars 
and  the  application  of  concrete,  that  this  is  only  an  improved  concrete.  The  cost  of  pro- 
duction has  been  too  great  to  admit  of  the  general  introduction  of  this  artificial  stone. 

Ransome's  patent  siliceous  stone,  being  one  of  the  most  successful  attempts  to  produce 
a  permanent  stone  artificially,  requires  a  little  further  attention. 

Mr.  Kansomc's  attention  was  directed  to  the  subject  of  artificial  stone  in  1844,  while  en- 
gaged as  manager  in  the  establishment  of  his  relatives,  the  Messrs.  Ransome,  of  the  Orwell 
\Vorks,  Ipswich.  At  that  time  the  above  named  firm  happened  to  have  a  considerable  order 
for  flour  mills  for  the  colonies  ;  and,  from  the  difficulty  experienced  in  refacing  the  French 
burr-stones,  usually  employed  for  the  purpose,  in  situations  where  skilled  labor  was  not 
attainable,  it  was  proposed  to  obviate  this  difficulty  by  substituting  for  the  stones  surfaces 
of  chilled  cast  iron.  It  was  found,  however,  that  after  a  while  the  grinding  surfaces  so  con- 
structed became  glazed,  and  conseejuently  unfit  for  the  purpose  for  which  they  were  intended. 
While  overlooking  the  proceedings  of  a  workman  engaged  in  renewing,  on  one  occasion, 
the  worn-out  ridges  on  a  burr-stone,  Mr.  Ransome  was  struck  by  the  apparent  absurdity  of 
having  to  chip  away  not  only  the  soft  parts  of  the  stone,  but  also  the  liard  siliceous  promi- 
nences which  constitute  the  real  efiicient  portion  of  the  surface.  From  tlie  unequal  and 
heterogeneous  character  of  the  burrs  usually  employed,  one  side  was  apt  to  wear  away 
sooner  than  the  other ;  and  to  bring  the  grinding  surface  to  any  thing  like  a  true  bearing, 
the  harder  portions  of  the  stone  had  to  be  cut  away  to  the  level  of  the  lower  and  softer 
parts ;  thereby  occasioning  not  only  great  labor  in  renewing  the  surface,  but  also  a  very 
rapid  destruction  of  the  whole  material. 

It  at  once  occurred  to  Mr.  Ransome,  that  if  he  could  procure  a  stone  of  perfect  homo- 
geneous texture,  the  surface  would  wear  down  equally,  and  this  objectionable  sj^stem  of 
levelling  the  whole  to  the  depth  of  the  softer  and  most  worn  parts  would  be  completely  ob- 
viated. Unfortunately,  however,  all  natural  stones  were,  from  their  very  nature,  of  unequal 
texture,  even  within  the  limits  of  the  small  segments  usually  employed  in  the  construction 
of  mill-stones.  Gathering  up  a  handful  of  the  chips  struck  oft"  by  the  tools  of  the  work- 
men, and  pressing  them  together,  the  idea  flashed  across  his  mind  that  if  he  could  discover 
any  means  of  cementing  those  particles  together,  he  would  be  able  to  produce  a  stone  of 
nearly  uniform  hardness  throughout.  The  most  convenient  material  for  this  purpose  that 
first  suggested  itself  was  plaster  of  Paris.  Tliis  idea  was  immediately  put  into  execution  ; 
and,  although  the  results  at  fii-st  off'ered  some  slight  prospect  of  success,  a  little  subsequent 
experience  sh.owed  the  utter  fallaciousness  of  the  hopes  he  had  entertained  concerning  them. 
But  from  the  first  moment  that  the  scheme  of  cementing  together  the  loose  and  disinte- 
grated fragments  of  the  mill-stone  entered  his  mind,  he  comprehended  by  anticipation  the 
whole  of  the  results,  which,  after  twelve  years  of  assiduous  application,  he  has  succeeded  in 
carrying  to  a  triumphant  conclusion. 

After  numerous  failures,  it  occurred  to  Mr.  Ransome  that  a  solution  of  silica  as  a  ce- 
menting material  would  )je  superior  to  any  other,  and  he  accordingly  started  on  the  inquiry 
after  an  easy  method  of  producing  a  solution  of  flints.  Experiment  proved  to  the  inventor 
that  flints  subjected  to  heat,  under  pressure  in  a  boiler  with  a  solution  of  soda  or  potash, 
were  dissolved. 

The  accompanying  illustration  gives  a  sectional  view  of  the  apparatus  employed  in  pre- 
paring the  siliceous  cement.  0 

A  is  a  steam-boiler,  capable  of  generating  a  sufficiency  of  steam  for  heating  the  dissolv- 
ing and  evaporative  vessels,  and  usually  worked  at  a  pressure  of  about  70  lbs.  to  the  square 
inch.  B  is  the  upper  lye-tank  for  dissolving  the  carbonate  of  soda.  It  is  supplied  with 
steam  by  the  pipes  1,  2,  3,  communicating  with  the  boiler. 

The  first  operation  is  to  reduce  the  ordinary  soda  ash  of  commerce  to  the  condition  of 
caustic  soda.  For  this  purpose  the  ash  is  first  dissolved  in  the  tank  b,  the  water  in  which  is 
heated  by  means  of  the  jiorforated  steam-pipe  h.  A  quantity  of  <iuick  lime  is  then  added, 
and  the  mixture  well  stirred.  The  soda  is  by  ttiis  means  dojirived  of  tl:e  carlionic  acid  which 
it  contains,  by  the  quick  lime  forming  with  it  a  carbonate  of  lime.  To  ascertain  when  the 
lye  is  quite  caustic,  a  small  portion  is  taken  out  in  a  test  tube,  and  a  few  drops  of  hydro- 
chloric acid  added.  If  tliere  is  no  effervescence,  it  may  be  assumed  that  the  soda  is  entirely 
li'  prived  of  its  carbonic  acid,  and  is  consequently  caustic.  Wlien  the  lime,  now  converted 
into  chalk,  has  subsided  to  the  bottom  of  the  tank,  the  clear  supernatant  lye  is  drawn  off  by 
the  siphon  5,  into  the  funnel  6,  leading  into  a  close  vessel  n,  to  prevent  the  carbonic  acid 
of  the  atmosphere  combining  with  it,  and  destroying  its  causticity.  When  tlie  lye  has  been 
drawn  off  from  n,  the  sediment  remaining  at  tire  bottom  of  the  tank  is  allowed  to  fall  into 
the  lower  tank  c,  by  withdrawing  the  plug  a  from  the  pipe  b\  Any  undissolved  crystals 
of  the  carbonate  of  soda  which  have  been  entangled  among  the  particles  of  the  lime  are 


STOKE,  ARTIFICIAL. 


1011 


now  washed  out  and  pumped  back  to  the  upper  tank  b,  where  it  forms  a  portion  of  the  next 
charge. 


The  clear  caustic  being  contained  in  the  close  tank  d,  has  a  further  process  of  depuration 
CO  undergo  before  it  is  ready  to  be  used  as  a  solvent  for  the  flints.  The  ordinary  soda  ash 
of  commerce  is  always  more  or  less  adulterated  with  a  sulphate  of  soda,  whieli,  although  an 
inert  substance  in  itself,  if  allowed  to  remain  in  the  cement,  subscquetitly  makes  its  appear- 
ance in  an  ugly  efflorescence  on  the  surface  of  the  finished  stone.  To  get  rid  of  the  sul- 
phate, the  caustic  solution  of  soda  has  added  to  it,  in  the  tank  n,  a  quantity  of  caustic 
baryta,  obtained  by  burning  the  commercial  carbonate  of  baryta  with  wood  cliarcoal.  The 
caustic  baryta  seizes  upon  the  sulphuric  acid  contained  in  the  sulphate  of  soda,  and  forms 
with  it  an  insoluble  sulphate  of  baryta,  which  is  precipitated  on  the  bottom  of  the  tank. 
The  depurated  lye  is  then  drawn  off"  by  the  pipe  d  into  the  lower  closed  tank  e,  and  the  sul- 
phate of  baryta  sediment  passes  off  by  the  cock  at  the  bottom.  From  e,  the  prepared  solu- 
tion of  the  caustic  soda  is  pumped  into  the  vertical  boiler  or  digester  f.  This  digester,  in 
which  the  process  of  dissolving  the  flints  is  eff'ected,  is  a  cylindrical  vessel,  having  a  steam- 
jacket  f,  into  which  steam  from  the  boiler  a  is  supplied  by  the  pipes  1,  2,  7.  The  inner 
cylinder  f  is  provided  witli  a  wire  basket  g,  reaching  the  whole  length  of  the  vessel,  and 
serving  to  hold  a  collection  of  nodules  of  common  flint.  "When  f  has  been  filled  with  the 
caustic  lye,  and  the  basket  with  flints,  the  manhole  at  the  top  is  closed  and  well  screwed 
down,  so  as  to  be  able  to  resist  a  pressure  of  at  least  60  lbs.  on  the  square  inch.  The  cock 
at  1  is  then  ©pened,  and  the  full  pressure  of  steam  from  the  boiler  i)asses  into  the  jacket  /, 
and  causes  the  lye  in  f  to  rise  to  the  same  temperature.  The  condensed  steam  in  the  jacket 
f  returns  to  the  boiler  by  the  pipe  12,  wliich  it  enters  below  the  water  line.  The  pressure 
maintained  in  the  digester  is  generally  about  00  lbs.,  an<l  tliis  is  continued  about  SO  hours; 
at  the  end  of  which  time  the  strength  of  the  solution  is  tested.  The  workmen  employed 
to  superintend  this  part  of  the  process  generally  use  the  tongue  as  the  most  delicate  test. 
If  the  solution  has  a  decidedly  caustic  alkaline  taste,  they  conclude  that  there  is  still  too 
much  free  soda  in  the  cement,  and  the  boiling  is  allowed  to  continue  until  the  cement  has  a 
slightly  sweetish  taste,  which  occurs  when  the  alkali  has  l)een  nearly  neutralized  by  combi- 
nation with  the  silicic  acid  of  the  flints.  A  more  scientific  moc](>  of  testing  the  strength  of 
the  solution  is  to  take  a  wine-glassful  and  drop  a  little  hydrochloric  acid  into  it ;  by  this 
means  the  wliolc  of  the  silica  in  the  solution  is  thrown  down  l)y  the  acid  combininir  witli  tlic 
'  soda,  so  as  to  form  chloride  of  sodium.  The  precipitated  silica  presents  an  apjiearancc 
resembling  half-<lissolved  snow,  and  its  comparative  volume  gives  a  good  idea  of  the  strength 
of  the  solutioii  of  the  alkaline  silicnte. 

When  it  is  judged  that  the  alkali  ha.s  taken  up  as  much  of  the  siHca  as  it  is  capable  of 
doing,  at  the  temjx'rature  to  which  it  is  subjected  in  the  dig(>ster,  the  stop-cock  7,  in  the 
steam-pipe  communicating  with  the  jacket,  is  shut,  and  a  cock  in  the  pipe  8  is  opened.  The 
pressure  of  the  steam  in  f  then  forces  the  fluid  silicate  through  the  pipe  8  into  the  vessel  ii, 


1012 


STONE,  ARTIFICIAL. 


where  it  is  allowed  to  stand  for  a  sliort  time  to  deposit  any  sediment  which  it  may  contain. 
From  II  it  is  then  conveyed  by  the  pipe  9  to  the  evaporating  pan  k,  which  has  a  steam- 
jacket,  A-,  supplied  with  steam  by  the  pipe  10.  The  cement  is  then  boiled  in  the  evaporating 
pan  until  it  becomes  of  the  consistency  of  treacle,  when  it  is  taken  out.  The  specific  grav- 
ity of  the  cement,  when  ready  for  use,  is  about  1-600.  The  general  proportions  of  the  ma- 
terials used  in  making  up  the  artificial  stone  are  about  the  following  : — 

10  pints  of  sand,  1  pint  of  powdered  flint,  1  pint  of  clay,  and  1  pint  of  the  alkaline 
solution  of  flint. 

These  ingredients  are  first  well  mixed  in  a  pug-mill,  and  kneaded  until  they  are  thor- 
oughly incorporated,  and  the  whole  mass  becomes  of  a  perfectly  uniform  consistency. 
When  worked  up  with  clean  raw  materials,  the  compound  possesses  a  putty-like  consistence, 
which  can  be  moulded  iuto  any  required  form,  and  is  capable  of  receiving  very  sharp  and 
delicate  impressions. 

The  peculiarity  which  distinguishes  this  from  other  artificial  stones  consists  in  the  em- 
ployment of  silica  both  as  the  base  and  the  combining  material.  Most  of  the  varieties  of 
artificial  stone  hitherto  produced  are  compounds,  of  which  lime,  or  its  carbonate,  or  sul- 
phate, forms  the  base  ;  and  in  some  instances  they  consist  in  part  of  organic  matters  as  the 
cement,  and  having  inorganic  matters  as  the  base. 

To  produce  difl'erent  kinds  of  artificial  stone,  adapted  to  the  various  purposes  to  which 
natural  stones  arc  usually  applied,  both  the  proportions  and  the  character  of  the  ingredients 
are  varied  as  circumstances  require.  By  using  the  coarser  description  of  grits,  grinding- 
stones  of  all  kinds  can  be  formed,  and  that  with  a  uniformity  of  texture  never  met  with  in 
the  best  natural  stones.  Any  degree  of  hardness  or  porosity  may  also  be  given,  by  varying 
the  quantity  of  silicate  employed,  and  subjecting  it  to  a  greater  or  less  degree  of  heat. 

For  some  descriptions  of  goods  a  portion  of  clay  is  mixed  with  the  sand  and  other  ingre- 
dients, for  the  double  purpose  of  enabling  the  material  to  stand  up  during  the  process  of 
firing  in  the  kiln,  and  to  prevent  its  getting  too  nmch  glazed  on  the  surface. 

The  plastic  nature  of  the  compound  allows  of  the  most  complex  and  undercut  patterns 
being  moulded  with  greater  ease  than  by  almost  any  other  material  we  are  acquainted  Avith, 
if  we  except  gutta  percha,  which,  however,  has  the  drawback  of  being  affected  by  common 
temperatures. 

The  moulds  employed  are  generally  of  plaster  of  Paris,  and  are  so  divided  as  to  allow 
of  the  difTcrent  pieces  which  cannot  be  withdrawn  together  being  separately  removed  from 
the  putty-like  substance  with  which  it  has  been  filled.  In  filling  the  moulds  the  workmen 
use  a  short  stick,  with  which  they  ram  in  the  material,  much  in  the  way  in  which  green  sand 
is  forced  into  contact  with  the  pattern  in  an  iron  foundry,  only  with  the  difference,  that  the 
sand  in  this  case  is  mixed  with  glutinous  cement,  which  enables  it  to  retain  the  form  im- 
pressed upon  it  with  much  greater  persistency  and  sharpness  than  is  practicable  with  dry 
sand,  or  even  loam.  The  casts,  after  being  taken  from  the  mould,  are  first  washed  over 
with  a  diluted  mixture  of  the  silicate,  technically  called  "  floating."  The  whole  surface  is 
then  carefully  examined,  and  any  broken  or  rough  portions  are  sleeked  with  a  tool.  It 
should  have  been  mentioned  that  tlie  plaster  of  Paris  moulds,  before  being  filled,  are  first 
painted  over  with  oil  and  then  dusted  with  finely-powdered  glass,  to  prevent  them  adhering 
to  the  cast. 

In  attempting,  however,  to  carry  out  his  plan,  two  difficulties  of  a  rather  formidable 
character  presented  themselves.  It  was  found  that,  in  the  process  of  desiccation,  the  sur- 
face of  the  stone  parted  with  the  moisture  contained  in  the  soluble  silicate,  and  became 
hardened  into  a  tough,  impervious  coating,  which  prevented  the  moisture  escaping  from  the 
interior  of  the  mass.  Any  attempt  to  dislodge  the  water  retained  in  combination  with  the 
silicate  in  the  interior  of  the  stone,  by  raising  the  temperature  of  the  whole  above  212  de- 
grees, had  merely  the  effect  of  breaking  this  outer  skin  of  desiccated  silicate,  and  rendering 
the  surface  cracked,  and  uneven. 

Instead,  therefore,,  of  allowing  the  stones  to  be  dried  in  an  open  kiln,  they  were  placed 
in  a  closed  chamber  or  boiler,  surrounded  with  a  steam-jacket,  by  which  the  temperature  of 
the  interior  chamljcr  could  be  regulated.  In  order  that  no  superficial  evaporation  should 
take  place,  while  the  stones  were  being  raised  to  the  temperature  of  the  steam  in  the  jacket, 
a  small  jet  of  steam  was  allowed  to  flow  into  the  chamber,  and  condense  among  and  on  the 
surfiice  of  the  goods;  until,  as  the  temperature  of  the  interior  of  the  stones  rose  to  212' 
and  upward,  they  became  enveloped  in  an  atmosphere  of  steam,  which  effectually  prevented 
any  hardening  of  the  surface.  The  minute  vents  or  spiracles  formed  by  the  steam  as  it  was 
generated  in  the  interior  of  the  ma.sses,  remained  open,  when  the  vapor  contained  in  the 
closed  chamber  was  allowed  slowly  to  escape,  and  afibrded  a  means  of  cgi'css  to  any  mois- 
ture wliieh  might  still  be  retained  among  the  particles  of  sand  and  cement.  The  whole  of 
the  moi.sture  contained  in  the  silicate  of  soda  having  been  thus  vaporized  before  it  left  the 
stone,  an  opportunity  was  afforded  it  by  opening  a  communication  with  the  external  atmos- 
phere, to  pass  off,  leaving  the  interior  of  the  stone  perfectly  dry.  Simiile  as  this  arrange- 
ment may  seem,  we  will  venture  to  say  that  not  one  of  our  readers  has  hit  upon  the  expe- 
dient through  his  own  cogitations  on  the  subject. 


STOKE,  ARTIFICIAL. 


1013 


The  process,  in  effect,  consists  in  stewing  the  stones  in  a  closed  vessel,  and  when  all  the 
moisture  which  they  contain  is  converted  into  vapor,  allowing  it  to  escape,  so  that  no  one 
part  of  the  mass  can  be  dried  before  another.  By  this  means  Mr.  Eansome  was  enabled  to 
desiccate  his  artificial  stone  without  any  risk  of  the  cracking  or  warping  which  had  hitherto 
been  the  result  of  his  attempts  to  harden  them  by  exposure  in  an  open  stove. 

After  being  thoroughly  dried  they  are  taken  to  the  kiln ;  but,  instead  of  being  placed  in 
sepgirs  or  boxes  of  clay,  as  is  usually  done  in  the  potter's  kiln,  the  goods  are  first  bedded 
up  with  dry  sand,  to  prevent  any  risk  of  their  bending  or  losing  their  shape  while  burning. 
Flat  slabs  of  fire-clay  are  then  used  to  separate  the  various  pieces  laterally,  and  similar  slabs 
are  placed  over  them  to  form  a  shelf,  on  which  another  tier  of  goods  is  placed.  The  tem- 
perature of  the  kiln  is  very  gradually  raised  for  the  first  twenty-four  hours ;  the  intensity  is 
then  augmented,  until  at  the  end  of  forty-eight  hours  a  bright  red  heat  is  attained,  when 
the  kiln  is  allowed  to  cool  gradually  for  four  or  five  days,  when  the  goods  are  ready  to  be 
taken  out. 

The  purposes  to  which  this  artificial  stone  is  now  applied  are  of  the  most  miscellaneous 
description,  comprising  grindstones,  whetstones  for  sharpening  scythes,  gothic  foliage  and 
mouldings  for  ecclesiastical  decorations,  tombstones  and  monumental  tablets,  chimney- 
pieces,  fountains,  garden  stands  for  flowers,  statuary,  &c. 

From  being  composed  almost  entirely  of  pure  siliceous  matter,  it  is  not  acted  upon  by 
acids,  and  is  apparently  quite  insoluble,  even  in  boiling  water. 

By  proportioning  the  amount  of  cement,  and  varying  the  character  of  the  sand  which 
enters  into  the  composition  of  the  stone,  it  can  be  made  porous  or  non-porous,  as  may  be 
desired.  The  average  absorbent  power  is  less  than  that  of  the  Bolsover  Moor  Dolomite 
used  in  the  erection  of  the  Houses  of  Parliament,  and  a  little  more  than  that  of  the  Crag- 
leight  Sandstone. 

DipPExnALL  Silica  Works,  Farxham,  Scrret. 
The  manufactory  which  bears  this  name  was  built  for  the  production  of  artificial  stone, 
from  a  material  only  recently  discovered,  and  never  before  employed  for  this  purpose : 
so'uhle  silica.  By  this  term  is  meant  that  kind  of  silica  which  is  found  to  be  readily  dis- 
solved by  boiling  in  open  vessels  with  solutions  of  caustic  potash  or  soda  ;  thus  distinguished 
from  the  silica  of  flint,  which  is  only  soluble  in  such  solutions  at  a  temperature  of  about 
300°  Fahr.  in  a  steam-tight  boiler ;  and  from  that  of  quartz  or  sand,  which  is  altogether 
insoluble.  Up  to  the  period  when  this  discovery  was  made,  silica  had  been  only  knoNvn  to 
exist  naturally  in  the  two  latter  forms,  and  the  former  was  merely  a  chemical  product,  de- 
rived from  one  of  them  by  artificial  means.  This  was  at  any  rate  the  case  in  England  ;  but 
it  is  riglit  to  state  that  a  somewhat  similar  deposit  was  mentioned  by  M.  Sauvage,  a  French 
chemist,  before  the  researches  were  made  to  which  this  paper  relates,  as  existinof  in  the  De- 
partment des  Ardennes.  This  information,  however,  has  not  been  turned  to  any  practical 
account ;  and  therefore  a  short  history  of  the  English  discovery  may  not  be  uninteresting, 
as  the  latter  has  introduced  to  the  world  a  new  material  applicable  to  a  great  variety  of 
purposes. 

About  ten  years  ago  the  late  Mr.  Paine,  of  Farnham,  proposed  to  the  Chemical  Commit- 
tee of  the  Royal  Agricultural  Society  of  England  that  a  complete  analysis  should  be  made 
of  all  the  soils  of  the  king  lorn,  for  the  purpose  of  ascertaining  their  value  as  natural  ma- 
nures. He  undertook,  for  his  own  share,  the  strata  of  the  chalk  formation  ;  and  his  thor- 
ough geological  knowledge,  aided  by  the  chemical  science  of  Professor  Way,  then  consult- 
ing chemist  to  the  Royal  Agricultural  Society,  enabled  him  fully  to  complete  the  inquiry. 

Some  of  the  results  of  this  joint  investigation  were  communicated  to  the  public  by 
Messrs.  Paiue  and  Way,  in  the  12th  volume  of  the  Journal  of  the  Royal  Agricultural  Soci- 
ety, in  a  paper  entitled  "  On  the  Strata  of  the  Chalk  Formation."  The" soluble  silica  deposit 
is  thus  described  : — "  Immediately  above  the  ganit,  with  the  upper  member  of  which  it  in- 
sensibly intermingles,  lies  a  soft  white-brown  rock,  having  the  appearance  of  a  rich  lime- 
stone. It  is  very  remarkable  on  account  of  its  low  specific  gravity,  and  still  more  so  con- 
sidering its  position,  by  reason  of  the  very  small  quantity  of  carbonate  of  lime  which  it 
contains.  It  is  one  of  the  richest  subsoils  of  the  whole  chalk  series,  being  admirably 
adapted  for  the  growth  of  hops,  wheat,  beans,  &c. 

At  the  enl  of  the  paper  it  is  remarked  that  a  careful  study  of  this  rock  may  throw  light 
upon  the  composition  of  soils. 

The  same  authors  contributed  another  article  to  the  1 1th  volume  of  the  "  Journal,"  on 
"  the  Silica  Strata  of  the  Lower  Ch:ilk,"  in  which  they  state  that  "  when  the  former  paper 
was  published,  they  were  not  unaware  that  this  stnitum  contained  a  large  proportion  of  silica 
in  the  form  which  chemists  call  "  .soluble  ;"  but  that  they  wished,  before  making  public  their 
discovery,  to  ascertain  whether  it  existed  in  sufficient  quantity  to  render  it  availal)le  forajri- 
cultural  use."  They  then  detail  the  result  of  their  researches  during  the  intervening  two 
years,  as  far  as  they  concern  agriculture,  mentioning  all  the  localities  in  which  this  stratum 
may  be  found  in  England,  anrl  the  various  ways  of  employing  it  beneficially  as  a  manure. 
T  icy  allude  to  the  fact  tiiat  it  will  be  found  useful  in  its  application  to  the  arts,  and  conclude 


1014 


STONE,  PRESERVATION  OF. 


with  these  remarks  on  its  probable  formation  : — "  It  is  not  infusorial,  for,  with  the  excep- 
tion of  a  few  f'oramiiiil'era,  no  traces  of  animal  life  can  be  observed  in  the  rock  by  micro- 
scopical examination.  It  cannot  have  been  subjected  to  heat  of  any  intensity,  or  it  would 
have  been  rendered  insoluble  in  alkalies.  It  is  plainly  the  result  of  aqueous  decomposition; 
and  it  seems  very  reasonable  to  suppose  that  silicate  of  lime  in  solution  derived  from  the 
older  rocks  may  have  met  with  carbonic  acid  produced  either  by  vegetaljle  and  animal  decay, 
or  by  volcanic  agency,  and  at  one  and  the  same  time  carbonate  of  lime  and  gelatinous  or 
soluble  silica  would  have  been  formed.  It  should  be  remembered  that  we  find  these  beds 
in  immediate  contact  with  the  chalk  ;  we  find  chalk  without  silica,  silica  without  chalk,  and, 
in  other  cases,  both  intimately  blended.  There  is  therefore  good  reason  for  supposing  that 
these  productions  have  been  in  some  way  connected." 

While  these  investigations  were  going  on,  it  was  also  found  that  the  new  material  was 
useful  in  a  variety  of  ways  quite  distinct  from  agriculture.  Mr.  Way's  experiments  led  to 
the  conviction  that  it  would  be  serviceable  in  sugar-refining,  in  soap-making,  in  making  ani- 
mal charcoal,  as  a  deodorizer,  and  above  all,  in  the  production  of  aitificial  stone. 

The  two  investigators  chiefly  turned  their  attention  to  this  latter  branch  of  the  subject ; 
and  in  1852  they  took  out  a  patent  for  "  Improvements  in  the  Manufacture  of  Burned  and 
Fired  Ware."  In  their  specification  they  lay  claim  to  the  production  of  a  superior  class  of 
burned  goo.ls  by  using  the  "  soluble  silica,"  with  such  admixtures  of  ordinary  clay  or  lime 
as  may  be  required.  By  these  means  they  propose  to  make  any  kind  of  artificial  stone, 
more  or  less  resembling  natural  stone ;  blocks  or  slabs,  excellent  building  bricks  of  any 
color,  and  good  fire-bricks.  They  do  not  claim  any  novelty  in  moulding  or  burning,  except 
that  they  consider  that  in  some  cases  articles  might  be  burned  to  a  slight  degree  of  hard- 
ness, then  finished  up  by  the  use  of  tools,  and  afterward  reburned  to  any  hardness  that 
might  be  required. 

Mr.  Paine's  many  other  duties  for  some  time  prevented  his  carrying  this  patent  into 
effect ;  but  at  last,  feeling  it  to  be  incumbent  on  him  to  make  public  so  important  a  discov- 
ery, in  spite  of  failing  health  and  arduous  occupation  he  commenced  building  the  "  Dippcn- 
hall  Silica  Factory"  in  1856.  Unhappily,  he  was  not  able  to  give  his  personal  attention  to 
the  manufacture,  so  that  it  never  had  the  benefit  of  his  experience  and  scientific  knowledge, 
and  his  death  in  1858  put  an  end  to  his  discoveries. 

The  factory  has  therefore  been  carried  on  from  the  first  under  serious  disadvantages ; 
but  enough  has  been  done  to  prove  that  its  founder  was  not  mistaken  in  the  importance 
which  he  attributed  to  the  invention.  It  is  at  present  managed  in  a  very  simple  manner. 
The  material  is  carefully  grouTid,  either  wet  or  dry,  according  to  the  purpose  for  which  it  is 
required,  and  mixed  with  clays  or  chalk  when  necessary.  The  bricks,  vases,  and  other  arti- 
cles, are  n:oulded  in  the  ordinary  way,  and  burned  in  round  kilna  The  building  bricks, 
vases,  and  terra-cotta  wares  of  all  descriptions  are  generally  acknowledged  to  be  superior 
to  any  thing  of  the  same  kind  hitherto  produced,  both  in  appearance,  finish,  and  durability. 
There  are  at  present  jiractical  difficulties  in  the  manufacture  of  large  blocks  of  stone,  which 
do  not  seem  to  have  been  contemplated  by  the  projectors  ;  and  the  fire-bricks  cannot  yet  be 
called  superior  to  the  Stourbridge  manufacture,  as  was  confidently  expected.  They  are  per- 
fectly infusible  under  any  amount  of  heat,  but  they  are  friable,  and  cannot  bear  a  sudden 
change  of  temperature.  Still,  when  it  is  remembered  that  the  works  have  been  carried  on 
without  any  assistance  from  without,  these  difficulties  only  serve  as  incentives  to  further 
endeavors ;  and  the  present  proprietor  is  convinced  that  all  that  is  required  to  overcome 
them,  and  to  raise  the  reputation  of  the  "  Dippenh.all  Silica  Works"  to  the  height  to  which 
their  originator  expected  it  to  attain,  is  a  man  of  equal  scientific  attainment,  to  resume  the 
labors  wliich  were  so  prematurely  arrested. — C.  P. 

STONE,  PRESERVATION  OF.  The  attention  of  the  scientific  world  has  for  some  time 
past  been  directed  to  the  importance  of  providing  a  means  for  protecting  the  stone  of  our 
public  buildings  from  the  ravages  of  time  and  the  injurious  efi'ects  of  the  polluted  atmos- 
pheres of  our  manufacturing  and  populous  districts. 

The  principal  cause  of  the  ruinous  decay  which  is  so  apparent  in  the  national  edifices, 
churches,  mansions,  &c.,  of  this  country,  is  generally  admitted  to  be  tiie  absorption  of  water 
charged  witli  carbonic  or  other  acid  gases,  which  by  its  chemical  action  either  decomposes 
the  lime  or  argillaceous  matter  forming  the  combining  nodiimi  unitirg  the  several  siliceous 
or  other  particles  of  which  the  stone  is  composed,  or  mechanically  disintegrates  those  par- 
ticles by  the  alternate  expansion  and  contraction  caused  by  variations  of  temperature. 

Many  processes  have  from  time  to  time  been  suggested,  and  several  patents  secured,  for 
filling  up  the  pores  of  the  stone,  and  thus  preventing  the  admission  of  these  deleterious 
agents;  hut  they  have  been  mostly,  if  not  entirely,  composed  of  oleaginous  or  gun.my  sub- 
stances or  compounds,  which,  although  possessing  for  a  time  certain  preservative  proper- 
ties, become  decomposed  themselves  upon  exj)Osure,  and  constantly  require  to  be  renewed ; 
whilst  from  the  nature  of  these  applications  the  discoloration  necessarily  produced  is  highly 
objectionable. 

A  little  reflection  will  be  sufiBcient  to  satisfy  a  thoughtful  mind,  that  in  seeking  for  a 


STOVE.  1015 

means  of  preserving  the  stone  of  our  national  buildings,  &c.,  we  ought  not  to  rest  satisfied 
simply  with  the  application  of  any  organic  substances,  however  great  may  be  their  apparent 
preservatis'e  qualities  for  a  time,  but  should  endeavor  to  supply  the  defects  of  nature  with 
an  indestructible  mineral  incapable  of  change  by  any  atmospheric  influences. 

The  process  of  silicatization  introduced  by  Kuhhnann  has  the  disadvantage  of  requiring 
some  considerable  time  before  the  atmosphere  can  do  its  work  of  effecting  the  necessary 
combination  between  the  silica  applied  in  solution  to  the  stone,  and  the  lime  contained  in 
it,  and  therefore,  when  it  is  applied  to  the  external  parts  of  any  building,  it  is  liable  to  be 
washed  out  before  solidification  has  been  secured.  Mr.  Fredericli  Ransouie,  advancing  from 
his  siliceous  stone  process  a  step  further,  meets  the  condition  by  eft'ecting  a  chemical  change 
at  once  within  the  stone.     Mr.  Ransome  thus  describes  his  process  : — 

"  Having  b?en  led  to  consider  the  importance  of  preserving  the  stone-work  of  our  pub- 
lic and  private  edifices  from  the  decay  resulting  from  the  variable  condition  of  our  climate, 
and  other  causes,  I  directed  my  attention  to  the  existing  processes  proposed  for  efiecting 
such  an  object,  and  more  especially  to  that  which  has  been  for  some  time  in  use  on  the  con- 
tinent, in  which  a  soluble  silicate  is  employed,  and  I  found  that  this  process,  though  having 
for  its  base  so  important  and  indestructible  a  mineral  as  silica,  was  nevertheless  very  imper- 
fect in  its  results.  It  appeared  to  me  that  one  great  cause  of  failure  arose  from  the  fact  that 
the  silicate,  being  applied  in  a  soluble  form,  was  liable  to  be  removed  from  the  surface  by 
rain,  or  even  the  humidity  of  the  atmosphere,  before  the  alkali  in  the  silicate  could  absorb 
sufficient  carbonic  acid  to  precipitate  the  silicate  in  an  insoluble  form.  But  another  great 
and  serious  defect  in  this  process  still  existed,  viz.,  that  even  were  it  possible  to  effect  the 
precipitation  of  the  silicate,  still  it  would  be  simply  in  the  form  of  an  impalpable  powder, 
possessing  no  cohesive  properties  in  itself,  and  therefore  able  to  afford  but  little,  if  any,  real 
protection  to  the  stone.  It  seemed  to  me,  therefore,  necessary  not  only  to  adopt  a  process 
which  should  insure  an  insoluble  precipitate  being  produced,  independently  of  the  partial 
and  uncertain  action  of  the  atmosphere,  but  that,  to  render  such  means  efficient,  a  much 
more  tenacious  substance  than  merely  precipitated  silica  must  be  introduced ;  and  in  the 
course  of  my  experiments  I  discovered  that,  by  the  application  of  a  second  solution,  com- 
posed of  chloride  of  calcium,  a  silicate  of  lime  would  be  produced,  possessing  the  strongest 
cohesive  properties,  and  perfectly  indestructible  by  atmospheric  influences.  The  mode  of 
operation  is  simply  this : — The  stone  or  other  material  of  which  a  building  may  be  com- 
posed, should  be  first  cleaned  by  the  removal  of  any  extraneous  matter  on  the  surface,  and 
then  brushed  over  with  a  solution  of  silicate  of  soda  or  potash,  (the  specific  gravity  of  which 
may  be  raised  to  suit  the  nature  of  the  stone  or  other  material ;)  this  should  be  followed  by 
a  solution  of  chloride  of  calcium,  applied  also  with  a  brush  ;  the  lime  immediately  com- 
bines with  the  silica,  forming  silicate  of  lime  in  the  pores  of  the  stone ;  whilst  the  chloride 
combines  with  the  soda,  forming  chloride  of  sodium,  or  common  salt,  which  is  removed  at 
once  by  an  excess  of  water.  From  the  foregoing  description  it  will  be  apparent  that  this 
invention  has  not  only  rendered  the  operation  totally  independent  of  any  condition  of  the 
atmosphere  in  completing  the  process,  but  the  work  executed  is  imaffeeted  by  any  weather, 
even  the  most  excessive  rains.  Experience  has  shown,  that  where  once  applied  to  the  stone, 
it  is  impossible  to  remove  it,  unless  with  the  surface  of  the  stone  itself.  I  do  not  confine 
myself  solely  to  the  solutions  above  referred  to  ;  in  some  cases  I  prefer  to  use,  first  a  solu- 
tion of  sulphate  of  alumina,  and  then  a  solution  of  caustic  baryta,  when  a  precipitate  of 
sulphate  of  baryta  and  alumina  is  formed,  the  main  object  being  to  obtain  two  or  more 
solutions,  which  upon  being  brought  into  contact  mutually  decompose  each  other  and  pro- 
duce an  indestructible  mineral  precipitate  in  the  structure  and  upon  the  surface  of  the 
stone. 

The  application  is  one  of  extreme  simplicity,  and  the  material  used  perfectly  indestruc- 
tible. The  rationale  of  the  process  is  thus  explained  :  a  liquid  will  enter  any  porous  body 
to  saturation,  whilst  a  solid  cannot  go  any  further  than  the  first  interstices  next  the  surface. 
Take,  then,  two  liquids  capable  of  producing,  by  mutual  decomposition,  a  solid,  and  by  the 
introduction  of  these  liquids  into  the  cells  of  any  porous  body,  a  solid  is  produced  by  their 
mutual  decomposition  internally;  erc/o,  if  a  solid  could  not  go  in  as  a  solid,  it  cannot  come 
out  as  a  solid,  and  chemical  decomposition  having  destroyed  the  solvents,  tliey  will  never 
again  be  in  a  state  of  solution.  The  patentee  has  secured  to  himself  the  application  of  this 
important  principle,  and  whilst  we  name  silicate  of  soda  and  chloride  ,of  calcium  as  the 
agent  under  mutual  decomposition  by  contact  for  producing  the  chloride  of  sodium,  and  the 
imperishable  silicate  of  lime,  there  are  many  other  ingredients  that  are  capable  of  producing 
like  results. 

STOVE.  Space  will  not  admit  of  our  descril)ing  the  Dutch  or  American  stoves,  which 
are  mainly  modifications  of  the  ordinary  forms,  which  are  sufficiently  well  known.  Pierce's 
pyro-pneumatic  stove-grate,  shown  firj.  028,  appears  to  meet  the  requirement  of  a  stove,  of 
an  open  fire,  and  good  ventilation,  in  a  remarkable  manner. 

In  the  annexed  sketch  is  delineated  the  operation  of  the  pyro-pneumatic  stove,  when 
employed  in  a  large  room,  fig.  624.      The  channel  c  serves  to  supply  pure  air  from  any 


1016 


STOVE. 


source  external  to  the  building.     The  amount  of  the  supply  is  regulated  by  the  valve  at  b, 
and  the  direction  of  the  currents  is  shown  by  the  arrows.     The  fresh  air  is  warmed  iu  its 


623 


course  through  the  stove,  and  ascends  to  the  ceiling,  where  it  becomes  diffused,  and  then 
descends,  passing  off  by  the  smoke-flue.  A  special  tube,  d,  is  provided  for  ventilating  the 
gas-lights,  as  exhibited  in  fig.  624. 


yy  yi  y  ii  d  'd  y  a  y  ii"  ii  i 


The  application  of  the  pjro-pneumatic  stove  to  tlie  warming  of  churches  is  extremely 
Bimplc,  and  its  eflects  arc  found  highly  satisfactory.     It  gives  an  abundant  supply  of  fresh 


STRUVE'S  MIXE  VENTILATOR.  1017 

air,  warmed  to  the  desired  temperature,  and  thereby  prevents  the  influx  of  an  impure  at- 
mosphere from  vaults  and  other  sources  of  pollution.  It  carries  off  the  vitiated  air  by  the 
smoke-due,  or  in  cases  where  a  more  rapid  ventilation  may  be  desirable,  the  warmth  which 
it  imparts  to  the  air  is  sufficient  to  create  an  ample  current  in  any  shaft  or  ventilator  that 
may  be  provided  i:i  tbe  roof  or  spire  of  the  building. 

In  all  cases  this  apparatus  is  economical  in  a  high  degree,  not  only  from  the  smallness  of 
its  first  cost,  but  also  froui  the  fact  that  the  full  effect  of  the  fuel  consumed  in  it  is  secured 
to  the  uses  of  warming  and  ventilation.  One  element  of  economy  cannot  be  too  strongly 
insisted  upon,  viz.,  the  feeling  of  warmth  and  comfort  (even  if  it  only  exist  in  the  imagina- 
tion) which  is  communicated  by  seeing  the  glow  and  blaze  of  an  open  lire. 

It  would,  perhaps,  be  no  exaggeration  to  say,  that  with  close  stoves,  heating  apparatus, 
and  other  arrangements,  in  whicU  tliere  is  no  appearance  of  warmth,  a  much  liiyher  temper- 
ature oft/ie  at  no  sphere  ix  rejuired  to  make  it  even  feel-  as  warm  as  in  that  of  an  apartment 
heated  by  an  open  fire.  Indeed,  it  may  be  fairly  asserted  that  most  persons  will  tolerate 
iucouvenienee  and  submit  to  expense,  provided  they  see  the  cheerful  blaze  of  the  open  fire, 
which  they  are  at  liberty  to  approach  at  will,  and  in  the  ever-varying  embers  of  which  they 
can  conjure  up  visions  of  the  past  and  fancies  of  the  future. 

One  of  the  large  pyro-pneu  natic  stove-grates,  when  in  full  operation,  is  found  to  be 
capable  of  healing  an  ap  irtment  containing  50,000  cubic  feet  of  air.  In  a  very  large  church, 
containing  upward  of  175,000  cubic  feet  of  air,  and  capable  of  accommodating  a  congrega- 
tion of  1,5  JO  persons,  four  of  these  stoves  of  moderate  size,  arranged  in  convenient  posi- 
tions toward  the  angles  of  the  building,  so  that  every  individual  of  the  congregation  may 
see  the  fire,  are  found  to  be  sufficient  in  the  coldest  weather,  and  do  not  even  require  to  be 
sustained  in  full  action,  except  during  a  few  hours  in  the  morning.  One  of  these  stove- 
grates  placed  in  the  hall  or  lower  part  of  a  staircase,  warms  and  tempers  the  internal  cli- 
mate of  a  large  hou-«e,  and  gives  the  whole  building  a  plentiful  supply  of  pure  fresh  air. 
One  of  the  s:niller  grates  is  capable  of  warming  a  large  room.  And  whether  in  dwelling- 
houses,  schools,  churches,  or  apartments,  the  arrangements  can  readily  be  brought  into  oper- 
ation at  a  moderate  cost,  and  without  any  (beyond  the  most  trifling)  interference  with  exist- 
ing structural  arrangements. 

The  same  inventor  has  introduced  what  he  calls  the  fresh  air  fire-lump  stove-grate,  which 
may  be  thus  described : — Tiiis  grate  is  formed  of  the  purest  and  best  fire-clay,  moulded  in 
suitable  forsns,  adapted  to  the  varied  arrangements  that  are  found  necessary,  and  consists 
of  the  open  fire-grate  bars  m  front,  surrounded  at  the  sides  and  back  by  the  fire-clay  lumps, 
around  which  lumps  an  air-chamber  is  formed,  communicating  with  the  external  atmosphere, 
admitting  air  to  a  cavity  in  the  lower  part  of  the  grate,  which  communicates  with  the  mouths 
of  the  vertical  channels  in  the  earthen  lumps  that  surround  the  fire.  The  warmth,  which 
is  communicated  to  the  air  through  the  body  of  these  lumps,  and  which,  from  their  small 
conducting  power,  rarely  exceeds  90',  and  can  never  be  excessive,  causes  it  to  ascend 
through  openings  in  the  upper  part  of  tlie  casing  into  the  apartment ;  its  place  being  sup- 
plied by  fresh  accessions  of  air  from  below.  The  warm  air  thus  admitted  into  the  apart- 
ment floats  above,  and  gradually  descends  as  it  cools,  its  place  being  supplied  by  warmer  air 
from  the  stove-grate,  and  taking  with  it  to  t!ie  fire  all  the  impurities  of  respiration,  which  is 
carried  away  by  the  flue,  in  which  the  heat  maintains  a  constant  upward  current.  Valves 
are  provided  for  regulating  the  quantity  and  temperature  of  the  fresh  air  admitted,  and  its 
distribution  into  the  apirtmsnt  when  warmed. 

STRIPPING  LIQUID,  SILVERSMITH'S,  consists  of  8  parts  of  sulphuric  acid  and  1 
part  of  nitre. 

STRU  VE'S  MIXE  VENTIL.iTOR.  The  striking  novelty  of  this  ventilator  is  the  gigan- 
tic scale  upon  which  it  has  been  constructed.  Although  in  principle  a  pump  of  the  simplest 
form,  some  of  the  pistons  have  been  made  20  feet  in  diameter,  and  two  pumps  are  about 
being  constructed  21  feet  in  diameter.     See  Ji;/.  625. 

In  some  mines  to  which  the  machine  has  been  applied,  the  rarcfixction  and  ventilation 
have  proved  so  strong  as  to  prevent  single  doors  being  opened,  unless  protected  by  supple- 
mental doors.  The  circumstance  of  the  air  not  being  compressed  in  the  machine,  admits 
of  large  valve  spaces,  so  that  there  is  scarcely  any  appreciable  resistance  to  the  passage  of 
the  air  through  the  machine. 

The  annexed  drawing,  firj.  625,  represents  the  machine  in  operation  at  the  Governor  and 
Company's  large  collieries  at  Cwm  Avon,  Glamorganshire;  and  the  following  list  of  licenses 
granted  to  several  large  colliery  proprietors,  is  a  convincing  proof  that  this  invention  ranks 
high  among  the  modern  improvements  of  mining. 

The  sectional  view  explains  the  internal  construction,  the  darts  showing  the  air-currents 
ascending  tlie  upcast  pit  a,  from  the  interior  of  the  mine  into  the  machine. 

The  piston  n  is  sliown  immersed  in  water,  which  forms  an  air-tight  packing. 

The  front  or  outlet  valves  K  are  shown  in  the  external  view  of  the  ventilator.  The  end 
of  the  machine  is  represented  open  in  the  drawing,  for  the  convenience  of  showing  the  inlet 
valves  E,  and  of  explaining  the  internal  construction. 


1018 


STRYCHNINE. 


The  air-ports,  or  valve-work,  can  be  made  three-fourths  of  the  area  of  the  pistons,  thus 
reducing  tlie  resistance  of  the  air-current  through  the  machine  to  a  minimum. 


A.  The  upcast  pit 

B.  Hollow  pistons,  made  of 
■wrought  iron. 

c.  Wrought  iron  tanks,  resting 
on  two  blocks  of  uiasonry,  and  on 
six  iron  pillars. 

D.  Beam  work,  resting  on  three 
blocks  of  masonry. 

E.  The  valve  work  and  framing, 
fastened  to  sixteen  upright  pieces  of 
timber,  9  inches  square. 

F.  Crank  wheel  of  steam  engine. 

G.  Piston  rods. 


These  machines  can  be  applied  to  winding  shafts. 

Cost  of  machines  about  £200,  for  capacities  of  10,000  cubic  feet  of  air  per  minute. 

STRYCHNINE.  C"H=^N■■'0^  The  bitter  poisonous  principle  contained  in  the  different 
varieties  of  utrj/chnos.  It  is  usually  extracted  for  commercial  purposes  from  the  nux  vomica 
bean,  the  seed  of  the  S.  nux  voynica.  It  is  a  well-marked  alkali,  and  yields  a  great  number 
of  crystalline  salts  with  acids  and  metallic  chlorides.  Its  true  constitution  has  been  fully 
made  out  by  the  researches  of  Messrs.  Nicholson  and  Abel.  Although  a  most  valuable 
medicine  in  paralytic  affections,  when  employed  in  very  small  doses,  it  is  a  dangerous  rem- 
edy in  unskilful  hands,  and  has  been  the  cause  of  numerous  deaths  arising  from  carelessness, 
without  reckoning  the  many  who  have  been  destroyed  by  it  at  the  hands  of  the  poisoner. 
Some  years  ago  a  panic  was  occasioned  by  a  rumor  of  its  employment  for  the  purpose  of 
giving  a  bitter  flavor  to  beer ;  this  has  been  shown  to  be  incorrect.  Still  the  quantities  of 
it  produced  annually  by  various  manufacturers  could  not  fail  to  excite  attention  and  uneasi- 
ness. As  much  as  1,000  ounces  have  been  known  to  be  purchased  at  one  time.  It  has 
been  proved,  however,  that  the  chief  use  is  for  the  destruction  of  wild  animals  in  Australia 
and  other  thinly  peopled  localities.  A  great  number  of  processes  have  been  devised  for  its 
preparation,  but,  after  having  been  subjected  to  the  extractive  operations,  the  bean  is  gen- 
erally found  almost  as  bitter  as  before,  indicating  a  want  of  economy  in  the  methods. 
Probably  the  best  method  of  extraction  would  be  to  disintegrate  the  beaus  with  stron?  sul- 


SUGAE.  1019 

phuric  acid,  (which  is  ■without  action  on  strychnine,)  and  then,  after  the  addition  of  excess  of 
alkah,  to  dissolve  out  the  base  with  benzole  or  chloroform.  The  latter  being  distilled  off 
would  leave  the  strychnine  nearly  pure,  and  only  requiring  crystallization.  It  has  been 
shown  by  John  Williams,  that  one  bean  will  by  this  process  yield  a  considerable  quantity  of 
crystals  of  pure  strychnine. 

The  detection  of  strychnine  has  unhappily  become  a  problem  of  only  too  frequent  occur- 
rence in  chemical  laboratories.  It  is,  therefore,  most  important  that  ready  and  accurate 
methods  should  be  known  for  the  purpose.  The  following  process  may  be  relied  on ;  it  is 
founded  on  that  adopted  by  Graham  and  Hofmann  for  the  detection  of  it  when  present  in 
beer.  The  stomach  or  other  organic  substance  is  to  be  cut  small  and  boiled  with  dilute 
hydrochloric  acid  for  a  quarter  of  an  hour.  The  acid  fluid,  after  filtration,  is  to  be  carefully 
neutralized  with  potash,  and  then  digested  with  recently  ignited  ivory  black.  The  charcoal 
is  to  be  separated  by  filtration,  and,  when  well  drained,  is  to  be  boiled  with  spirit  of  wine. 
The  strychnine  which  will  have  been  absorbed  by  the  charcoal  will  be  dissolved  out  by  the 
spirit.  The  latter  is  then  to  be  distilled  off  on  the  water  bath.  The  contents  of  the  retort, 
being  transferred  to  an  evaporating  basin,  are  to  be  exposed  on  the  water  bath  until  dry. 
The  residue  is  then  to  be  tasted ;  if  bitter,  the  process  may  be  completed,  but  if  no  bitter- 
ness is  observed  it  is  scarcely  worth  while  to  proceed,  as  the  merest  trace  of  strychnine  is 
capable  of  exciting  the  sense  of  extreme  bitterness.  The  residue  is  to  have  a  slight  excess 
of  potash  added,  and  is  to  be  shaken  up  with  chloroform.  The  chloroform  being  separated 
is  to  be  evaporated  oif.  The  operation  must  be  repeated  if  the  product  be  colored.  The 
substance  thus  obtained  is  to  have  a  little  strong  oil  of  vitriol  added,  and  a  piece  of  bichro- 
mate of  potash  is  to  be  rubbed  on  the  parts  where  the  strychnine  is  supposed  to  be ;  if  pres- 
ent, rich  deep  purple  streaks  will  become  evident. — C.  G.  W. 

SUGAR.  The  following  will  show  the  composition  of  the  various  sugars,  and  their 
principal  combinations  with  bases: — 

Cane  sugar,  or  sucrose         -         .         .         .         .         C'"H"0" 
Grape  or  starch  sugar,  or  glucose        ...         C'-H''^0",2II0 

Fruit  sugar,  or  fructose C'^H'-O"  at  212°  F. 

Milk  sugar,  or  lactose C'^IP^0'^.5H0 

Manna  sugar,  or  mellitose  -        ...        -        C-*H**0",4H0 

Compounds  of  cane  sugar  called  sugarates. 

With  soda NaO,C'"H"0» 

With  potash       ....-•-.        KO,C"H"0" 

With  lime CaO,C''H"0" 

With  baryta BaO,C'=H"0" 

With  lead C"^^0",  or  2PbO,C''ffO» 

With  common  salt NaCl.C^^IP'O'^' 

Compounds  of  grape  sugar ^  or  glucose. 

With  baryta C^V.O'^  6H0,  or  SBaO,C=*H'*0*' 

With  lime C-*^^0-^  6H0,  or  3CaO,C-''H=^0=« 

Pb=' 

With  common  salt C^<H'=*0=^NaCl,2H0 

Cane  sugar  is  soluble  in  all  proportions  in  boiling  water,  and  in  \  of  cold. 
It  is  sparingly  soluble  in  alcohol  of  70  per  cent,  and  insoluble  in  absolute  alcohol. 
The  followiug  Table,  by  Payen,  shows  the  quantity  of  sugar  contained  in  saccharine  solu- 
tions of  various  specific  gravity  at  59^  F. : — 


With  lead 


Parts  of  Parts  of  Specific 

sugar.  water.  gravity. 

luO  dissolved  in    5U  give  a  syrup  of  1  -S-to 


100 

60 

100 

no 

100 

80 

100 

90 

100 

100 

100 

120 

100 

140 

100 

160 

100 

180 

100 

200 

Parts  of  Parts  of  Specific 

sufcar.  water.  gravity. 

100  dissolved  in  25(i  give  a  syrup  of  1-147 

Mil 
"  1-089 

"  1-074 

"  1-063 

"  1-055 

1-045 
1-030 
''■  1-022 

"  1-018 

"  1-015 


1-322 

100 

350 

1-297 

100 

450 

1-281 

100 

550 

1-266 

100 

65D 

1-257 

100 

750 

1-222 

100 

945 

1-200 

100 

1145 

1-187 

100 

1945 

1-176 

loo 

2445 

1-170 

100 

2945 

1020 


SUGAE. 


The  annexed  Table,  cDnstnicted  by  Neimann  for  the  normal  temperature  of  63",  with  the 
same  object,  is  also  submitted  : — 


Sugar. 

Water. 

Specific   Gravity. 

Su^ar. 

Water. 

Specilic  Gravity. 

Sugar. 

Water. 

Spucific  Gravity 

0 

100 

1-0(1(10 

24 

76 

IIUIO 

4S 

52 

1-2209 

1 

99 

1-0035            1 

25 

75 

1-1(156 

49 

51 

1-2265 

2 

98 

10070 

26 

74 

11103 

50 

50 

1-28-22 

3 

97 

1-0106 

27 

73 

11150 

51 

49 

1-2378 

4 

96 

10143 

1       28 

72 

1-1197 

52 

48 

1-2484 

5 

95 

10179 

29 

71 

11245 

63 

47 

1-2490 

6 

94 

10215 

30 

70 

1-1-293 

54 

46 

1-2546 

7 

93 

10254 

31 

69 

1-1840 

55 

45 

1-2602 

8 

92 

10291 

82 

63 

118S3 

56 

44 

1-2658 

9 

91 

1-032S 

83 

67 

11430 

57 

43 

1-2714 

10 

90 

1-IUS67 

84 

66 

114s4 

58 

42 

1-2770 

11 

89 

1-0410 

85 

65 

1-1533 

59 

41 

1-2826 

13 

&8 

1-0456 

36 

64 

1-1 5b3 

60 

40 

1-2882 

13 

87 

1-0504 

37 

C3 

1-1C31 

61 

89 

1-2933 

14 

86 

1-0552 

38 

63 

1-1 6S1 

62 

38 

1-2994 

15 

85 

1-0600 

89 

61 

1-1731 

68 

87 

1-3050 

16 

84 

1-0647 

40 

60 

1-1781 

64 

86 

1-3105 

17 

83 

1-069S 

41 

59 

1-1S83 

65 

35 

1-3160 

13 

82 

1-0734 

42 

58 

11SS3 

66 

84 

1-3215 

19 

81 

1-07S4 

43 

57 

11935 

67 

83 

1-8270 

20 

80 

10S30 

44 

56 

1-19S9 

68 

82 

1-3824 

21 

79 

1-0S75 

45 

55 

1-2043 

69 

81 

1-8377 

22 

7S 

10920 

46 

54 

1-2098 

70 

80 

1-3430 

23 

77 

1U9G5 

47 

53 

1-2153 

1 

The  specific  gravity  of  crystallized  cane  sugar  is  r594.  Crystallized  cane  sugar  seems 
to  be  the  most  complete  type  of  sugar  known.  Its  crystals  are  the  largest  aud  most  regular, 
and  its  taste  the  sweetest.  These  crystals  aie  rhomboidal  prisms,  and  appear  largest  in  the 
form  of  sugar  candy.  When  boiled  much  or  heated  with  acids  it  would  appear  that  a  lower 
form  of  sugar  resulted,  namely,  grape-sugar.  This  sugar  crystallizes  with  difficulty  in  tufts 
of  small  needles.  When  the  same  treatment  is  further  continued  the  power  to  crystallize 
is  entirely  lost.  It  has  been  attempted,  but  without  success,  to  reverse  these  processes. 
The  solution  of  this  problem  would  be  of  great  value  to  the  woild,  and  already  much  time 
and  talent  have  been  expended  upon  it. 

At  300°  sugar  loses  0'6  per  cent.,  and  remains  uninjured  after  seven  hours;  it  melts  at 
320",  and  at  this  point  it  seems  to  have  lost  some  of  its  sweetness,  and  probably  a  portion 
of  water.  The  same  result  is  obtained  at  a  lower  temperature  if  more  time  is  allowed.  The 
color  is  changed  to  an  orange-yellow  af  410":  the  sugar  loses  three  equivalents  of  water, 
becomes  gradually  brown,  has  an  empyrcuniatic  taste,  and  is  called  caramel.  With  a  heat 
approaching  to  a  red  heat,  cavburetted  hydrogen,  carbonic  acid,  acetic  acid,  and  empyreu- 
matic  oils  are  produced,  and  carbon  remains,  am.ounling  to  25  per  cent,  of  the  original 
mass.  This  disengagement  of  gases  occurs  with  immense  enlargement  of  volume,  so  that 
the  carbonaceous  residue  is  rendered  exceedingly  porous.  If  these  gaseous  products  are 
inflamed,  which  may  be  done  at  500",  the  amount  of  heat  disengaged  is  very  great.  It  is 
believed  generally  that  a  perfectly  pure  solution  of  cane  sugar  in  water  will  not  decompose: 
this  certainly  is  found  to  be  the  case  in  very  dense  solutions,  at  least  after  the  lapse  of  several 
years ;  but  when  weak  solutions  are  used,  decomposition  is  effected  in  the  course  of  a  few 
mouths,  even  though  the  sugar  is  pure,  the  water  distilled,  and  the  vessel  remain  unojjened. 

Solutions  of  sugar  are  readily  decomposed  by  acids  as  well  as  by  acid  salts  of  every  kind. 
They  are  decomposed  also  almost  as  readily  by  caustic  alkaline  solutions,  and  by  hot  solu- 
tions, of  the  carbonated  fixed  alkalies,  t'nder  the  name  alkaline  sc'lutions  must  be  included 
both  baryta  and  lime,  if  heat  is  to  be  long  used ;  but  both  of  these  substances  form  com- 
pounds with  sugar,  the  first  of  which  will  be  treated  of  when  beet-root  sugar  is  under  con- 
sideration. The  compound  of  sugar  and  lime  is  very  soluble  in  cold  water,  but  is  precipi- 
tated on  heating.  The  amount  dissolved  is  shown  to  be  a  true  equivalent,  liy  tl.e  inquiries 
of  Peligot,  who  has  proposed  an  ingenious  method  of  ascertaining  the  amount  of  sugar  in  a 
solution  by  the  estimation  of  the  lime  which  it  will  dissolve.  The  lime  in  this  process  is 
estimated  alkalimctrically  by  means  of  an  acid.  The  Table  on  the  following  page  has  been 
constructed  by  M.  Peligot  for  calculating  the  results. 

Sugar  has  the  capacity  of  reducing  many  of  the  higher  to  lower  oxides,  and  also  of  en- 
tirely reducing  the  oxides  of  some  of  the  metals.  At  the  same  time  it  effects  the  oxidation 
of  some  of  the  commoner  metals,  and  keeps  the  oxides  in  solution.  As  an  example  of 
these  actions,  the  hydrated  peroxide  of  iron  is  reduced  to  protoxide,  and  retained  in  solution, 
whilst  the  hydrated  oxide  of  copper  is  reduced  to  the  suboxide  and  precipitated  in  solutions 
both  of  grape  sugar  and  uncrystallizable  sugar.  This  action  has  been  pioposcd  as  a  mode 
of  estimating  the  proportion  of  grape  and  uncrystallizable  sugar  in  sacchaiine  solutions,  as 
will  be  shown.  Iron  is  readily  acted  upon  by  grape  and  uncrystallizable  sugar,  and  is  re- 
tained in  solution  by  sugar  of  every  kind.  Neither  iron,  zinc,  nor  lead  is  thrown  down 
from  sugar  solutions  by  the  usual  alkaline  reagents,  but  sulphide  of  ammonium  separates 
them  cntirclv. 


SUGAR. 


1021 


Quantity  of  sugar 
dissolved  in  100 

Density  of  syrup. 

Density  of  syrup 
when  saturated 

100  parts  of  residue  dried  at  120° 

jiarts  of  water. 

with  lime. 

Lime. 

Sugar. 

40-0 

1-122 

1-179 

21-0 

79-0 

37-5 

1-116 

1175 

20-8 

79-2 

85-0 

1-110 

1-166 

20-5 

79-5 

32-5 

1-103 

M59 

20-3 

79-7 

30-0 

1-096 

1-148 

20-1 

79-9 

27-5 

1-089 

1-139 

19-9 

80-1 

25-0 

1-082 

.  1-128 

19-8 

80-2 

22-5 

1-075 

1-116 

19-3 

80-7 

20-0 

1-068 

1-104 

18-8 

81-2 

17-5 

1-060 

1-092 

18-7 

81-3 

15-0 

1-052 

1-080 

18-5 

81-5 

12-5 

1-04-t 

1-067 

18-3 

81-7 

10-0 

1-036 

1-053 

18-1 

81-9 

7-5 

1-027 

1-040 

16-9 

83-1 

5-0 

1-018 

1-026 

15-3 

84-7 

2-5 

1009 

1-014 

13-8 

86-2 

Saccharimetry. — We  now  come  to  the  estimation  of  sugar,  which  is  most  simply  per- 
formed by  the  hydrometer,  when  the  solutions  are  pure  and  the  kind  of  sugar  known.  But 
commercially  it  is  required  to  ascertain  the  proportions  of  cane  sugar,  uncrystaUizable  sugar, 
water  and  impurities,  and  this  is  accomplished  most  successfully  by  means  of  the  polarizing 
saecharometer  proposed  by  Biot  and  improved  by  Solcil.  The  following  is  a  description  of 
this  beautiful  instrument: — Two  tubular  parts,  t  t',  and  t"  T"\fi(/s.  627  and  G'iS,  constitute 


tlie  principal  part  of  the  s  iccharometcr.  The  light  enters  v,  tln-ough  a  Xicol's  prism  q, 
shown  separately,  fiff.  627,  at  o,  and  passes  tirst  an  achromatic  polarizing  prism  p,  and 
shown  separately  at  i'  and  afterwards  through  a  plate  of  quartz  of  double  rotation  at  p\ 
which  is  also  shown  at  (j.  This  plate  is  composed  of  two  semi-discs  cut  pori)endicularly  to 
the  a.xis  of  crystallization  ;  but,  though  exactly  of  ccpial  thickness  and  equal  rotating  power, 
the  one  turns  the  ray  to  the  right,  while  the  other  turns  it  to  the  left.  At  y/',  the  ray  passes 
a  plate  of  quartz  of  single  rotation,  and  at  /  l\  two  wedges  of  quartz  endued  with  the  i)ower 
of  rotation,  but  in  a  contrary  direction  to  the  preceding  plate.  These  two  wedges  are  again 
represented  in  a,  and  arc  so  made  that  by  turning  the  milled  head  n,  the  sum  of  their  thick- 
ness can  be  increased  or  diminished  at  pleasure,  while  the  amount  of  thickness  is  shown  by 
the  ivory  graduated  scale  e  e',  and  vernier  ii  r'.  l''inally  the  ray  traverses  an  analyzing  prism 
«,  and  an  eye-piece  l.     If  the  instrument  is  directed  to  the  light  the  observer  will  see  a 


1022 


SUGAK. 


luminous  disc,  bisected  by  a  central  line  (produced  by  the  junction  of  the  two  semi-discs  of 
quartz)  of  exactly  the  same  tint,  but  which  tint  may  be  varied  at  pleasure,  by  rotating  the 
iS'icol's  prism  n,  by  means  of  the  milled  head  6.  If,  however,  we  interpose  between  p'  and 
p'\  the  tube  c,Jig.  627,  filled  with  a  solution  of  cane  sugar,  and  the  ends  closed  with  glass, 


028 


the  semi-discs  will  be  differently  colored.  Cane  sugar,  possessing  the  power  of  circular 
polarization,  combines  with  the  rotating  power  of  the  half  disc  which  turns  the  ray  to  the 
right,  but  tends  to  neutralize  the  half  disc,  whose  direction  is  the  reverse.  By  increasing  or 
diminishing  the  thickness  of  the  wedges  of  quartz  /  l\  to  the  extent  required  for  coun- 
teracting their  rotation  to  the  right,  and  causing  the  semi-discs  to  reassume  the  same  colors, 
we  have  a  means  by  the  graduated  scale  e  e\  v  v',  of  measuring  the  rotating  power,  which 
is  exactly  proportional  to  the  amount  of  cane  sugar,  temperatures  being  equal,  and  no  for- 
eign substance  having  the  power  of  circular  polarization  being  present. 

To  apply  this  method,  the  deviation  must  be  known  which  is  produced  by  a  solution  of 
sugar  of  known  strength.  For  this  purpose  a  given  weight,  e,  of  sugar  is  dissolved  in  such 
a  quantity  of  distilled  water  that  the  solution  occupies  a  given  volume,  V.  Sufficient  of  this 
solution  is  taken  to  till  a  tube  of  a  certain  length,  and  the  deviation  suffered  by  the  plane  of 
polarization  of  the  luminous  ray  passing  through  this  tube  is  measured.  Let  this  deviation 
be  a..  Let  then  other  quantities  of  sugar  be  dissolved  in  sufficient  water  to  give  the  same 
volume  of  solution,  V ;  and  let  the  deviations  produced  by  these  solutions  in  the  same  tube 
be  a   o",  a",  &c. ;  then  the  quantities  of  sugar  contained  in  the  volume,  V,  of  these  liquids 

will  be  represented  by  the  products  e  — ,  e — ,  e — ,  &c.,  respectively.     If  the  sugar  exam- 

a  a  a 
ined,  instead  of  being  pure,  is  mixed  with  other  but  inactive  substances,  it  is  evident  that 
these  same  products  express  the  absolute  weights  of  pure  sugar  contained  in  the  weights  of 
substances  employed  in  the  formation  of  the  licjuids  of  the  given  volume,  V.  It  is  possible 
to  employ  proof  tubes  of  different  lengths ;  but  it  is  then  necessary  to  reduce  by  calculation 
the  observed  deflections  to  those  which  would  have  been  produced  in  the  same  tube. 

It  often  happens  that  solutions  of  sugar  which  have  to  be  examined  are  turl)id  or  strongly 
colored.  When  this  interferes  with  the  examination,  they  must  be  clarified  and  rendered 
either  quite  colorless,  or  when  this  is  not  possible  the  color  must  be  at  least  reduced.  This 
is  often  effected  by  precipitating  the  coloring  matter  of  the  syrups  with  subaeetate  of  lead ; 
but  the  most  accurate  method  is  by  a  filter  of  animal  charcoal.  The  filtrates  aie  then  ex- 
amined. When  syrups  contain,  besides  cane  sugar,  other  constituents  which  exert  an  action 
upon  the  plane  of  polarization,  the  amount  of  cane  sugar  present  may  be  determined  bj'  in- 
verting, by  means  of  hydrochloric  acid,  the  rotary  power  of  the  cane  sugar.  No  other  sac- 
charine substance  is,  in  fact,  known  which  suffers  a  similar  change  under  the  same  circum- 
stances. 

If,  for  instance,  the  liquid  under  examination  contains  besides  cane  sugar,  glucose,  whose 
rotary  action  on  the  plane  of  polarization  is  in  the  same  direction  as  that  of  cane  sugar;  if 
a  be  the  deviation  observed  to  be  produced  by  the  liquid,  then  a  is  evidently  the  sum  of 
the  separate  deflections  of  the  cane  sugar  .r,  and  of  the  glucose  y.  About  one-tenth  of  its 
volume  of  hydiochloric  acid  is  added  to  the  syrup,  and  it  is  kept  for  ten  minutes  at  a  tem- 
perature of  140' — 154°.  The  cane  sugar  is  theicby  completely  transformed  into  noncrys- 
tallizable  sugar,  which  turns  the  plane  of  polarization  to  the  left,  while  the  rotary  power  of 
the  glucose  undergoes  no  alteration.  When  tliis  change  has  been  efl'ected,  the  new  deviation, 
a",  of  the  liquid  is  observed.  It  is  now  the  difference  between  the  deviation  _(/  of  the  glucose 
and  that  of  the  noncrystallizablc  sugar  derived  from  the  cane  sugars.  But  the  degree  of 
dilution  of  the  liquid  having  been  changed  by  the  addition  of  the  hydrochloric  acid,  the  de- 
viation observed,  o",  must  be  replaced  bv  the  deviation,  . —  o",  which  would  have  been  ob- 

9 
served  if  il.o  inversion  could  have  been  produced  without  the  addition  of  hydrochloric  acid. 


SUGAR.  1023 

Admitting  therefore  that  a  quantity  of  cane  sugar  which  effects  a  deviation,  x,  gives  rise  to 
a  quantity  of  noncrystallizaljle  sugar  which  effects  a  deviation,  r  x,  we  have — 
Before  the  inversion,  x+y=  a. 

After  the  inversion,  y+r  x  =■  —  o". 
9 
From  tliese  two  equations  the  quantities  x  and  y  may  be  determined.     Tlie  coefficient  of 
inversion,  r,  is  determined  once  for  all  by  a  special  experiment  performed  upon  pure  cane 
su^ar  at  the  temperature  at  which  the  experiments  have  afterwards  to  be  made.     According 
to  Biot,  this  coefficient  is  0-038  for  hydrochloric  acid  at  a  temperature  of  71-6°. 

The  process  is  the  same  when  the  cane  sugar  is  mixed  with  noncrystallizable  sugar, 
turning  the  plane  of  polarization  to  the  left.  In  this  case  the  initial  deviation,  o',  of  tlie 
liquid  is  the  difference  between  the  deviation  to  the  right,  »•,  of  the  cane  sugar,  and  the  de- 
viation, 2,  to  the  left  of  the  noncrystallizable  sugar.  After  treating  with  hydrochloric  acid, 
the  deviation,  a",  is  composed  of  the  deviations  of  the  original  noncrystallizable  sugar,  and 
of  that  produced  by  the  action  of  the  hydrochloric  acid.  We  then  have — 
Before  inversion,  x  —  z=za'. 

Aft     •  •  ,  10     •• 

Alter  mversion  z+r  x= —  a  . 

9 

It  is  important,  in  examining  optically  noncrystallizable  sugar,  always  to  employ  the  same 
temperature,  because  a  change  of  temperature  materially  affects  the  rotary  power  of  this 
kind  of  "sugar. 

The  table  appended  includes  each  degree  of  temperature  from  +10  to  +35  centigrade, 
and  for  qualities  increasing  in  hundredths,  this  range  being  found  sufficient  for  all  practical 
purposes  either  in  Europe  or  the  colonies. 

To  note  the  temperature  at  which  the  observation  is  made,  a  tube  z  z,_fig.  627,  provided 
with  a  vertical  branch,  is  employed.     In  this  branch  a  thermometer,  t,  is  placed. 

The  following  are  two  examples  of  the  use  of  the  table ; 

1.  A  solution  of  a  saccharine  substance  prepared  in  the  normal  propor- 
tions of  weight  and  volume  recommended,  and  giving  before  acidulation  a 

notation  on  the  left-hand  part  of  the  scale  of 75  divisions. 

And  after  the  inversion  (the  temperature  being  +15°)  a  notation  in  the 
opposite  direction  of 20  divisions. 

Sum  of  the  inversions 95  divisions. 

2.  Another  liquor  similarly  prepared,  giving  before  the  inversion  a  no- 
tation on  the  left  of 80  divisions. 

And  after  the  inversion,  at  the  temperature  of+20°,  another  notation  of 
the  same  direction,  but  only  of 26  divisions. 

Difference  expressing  the  value  of  the  inversion  -         -     54  divisions. 

The  strength  of  the  two  solutions  will  be  found  thus ;  for  the  first,  by  seeing  what  is  the 
figure  of  the  column  representing  15°,  which  is  the  nearest  to  the  sum  of  the  inversion,  95 
divisions:  it  will  be  observed  that  this  figure  is  95-5,  and  that  it  corresponds  to  quality  70, 
shown  on  the  same  horizontal  line  in  the  last  column  but  one,  A ;  hence  we  conclude  that 
the  substance  contained  70  per  cent,  of  sugar. 

As  to  the  second  solution,  the  figure  nearest  54  is  53-0,  in  the  column  for  the  tempera- 
ture of+20°,  and  the  strength  sought  will  be  40"  „  on  the  same  line  in  tlie  column  of  quali- 
ties. Finally,  we  shall  find,  besides,  in  the  last  column,  B,  of  the  table,  the  quantity  in 
grammes  and  centigrammes  of  the  sugar  contained  per  litre  in  the  solutions,  which  is  114 
gr.  45  for  the  first,  and  C5  gr.  40  for  the  second. 

Other  methods  for  the  estimation  of  sugar  have  been  adopted.  We  have  already  do- 
scribed  Peligot's  method  l)y  means  of  lime.  When  sugar  is  formed  from  starch,  its  com- 
plete saccharification  may  be  determined  by  the  action  of  sulphuric  acid  ;  for,  if  on  a  strong 
solution  of  imperfectly  formed  grape  sugar,  nearly  boiling  hot,  one  drop  of  strong  sulphuric 
aciil  be  added,  no  perceptible  change  will  ensue,  Ijut  if  the  acid  be  dropped  into  solutions 
of  either  cane  or  perfectly  formed  grape  sugar,  black  carbonaceous  particles  will  make  their 
appearance. 

The  l)lack  oxide  of  copper  is  not  affected  by  being  boiled  in  solution  of  starch  sugar. 

"If  a  solution  of  grape  sugar,"  says  Troramer,  "and  potash,  be  treated  with  a  solution 
of  sulphate  of  copper,  till  the  separated  hydrate  is  re-dis.solved,  a  precipitate  of  red  oxide 
will  soon  take  place,  at  common  temperatures,  but  it  immediately  forms  if  the  mixture  is 
heated.  A  lifjuid  containing  '/looooo  of  grape  sugar,  even  one-millionth  part,"  says  he, 
"gives  a  perceptible  tinge  (orange)  if  the  light  is  let  fall  upon  it."  To  olitain  such  an  ex- 
act result,  very  great  nicety  must  be  used  in  the  dose  of  alkali,  whieli  is  found  extremely 
difficult  to  hit.  With  a  regulated  alkaline  mixture,  however,  an  exceedingly  small  portion 
of  starch  sugar  is  readily  detected,  even  when  mixed  with  Muscovado  sugar. 


1024 


SUGAK. 


E      Sip 


-     S^ 


«       5p-r 


^      S  a 


2  S 


H       => 


1^     .=     -5=: 

2    .^   's- 


—I       p    .—  a 


r?     —  £^1^.^* 


v:         <n  ?  ^  =3 

5  =r:^'3 


—  .-'•  • 


<   ^  s  -  = 

"     2  5-2 

^  x'o.ip 


c  e  ?-3 


E.a.i-g 

^©•3  2 


S4 

2, 

1  t-T  ci  CO  o  «'  t-'  oT  cT  — '  c^'  :c  ^d  \d  t^  cC  :^'  —  ^i  -r  o  tc  r  -  cC  ='  —  c^i 

— ^  -3*  t-  c;  ^1  L-^  t-  o  cc  o  CO  ^ 
"T  *."'  •-^*"  w  C;  cT  — '  cc  '^'  i.-^'  t;  -rT 

3 

^ 

^ 

-^'iM'ec  .c'«e't-i »'  cT  — ■  -m'  ir-r-  -.c'l-'  =v  cT  —'  -m'  Tt  tt'  s:  i-.^  ci  o  — '  rr 

«  -.i_QC  ^_-r,-.C  ~.  n  -p  t-  o  M 

-t  «  5=  cc  C-.  =;  —  sc  -T  i--;  1-'  jj" 

=H 

K -a  oa  r^  •*  t~  Oi  oi  t^  t~  z^^x  ~  x  — ^r-cs-MKixoKscos  — 
r^^ci  m'o  «'«r^  X  =;'— ?i  -rv-'-.c"(-.'c-r='— '^'^'o'^'  00  —  —  ,-'^^' 

-T  t-;  — ,^J  O  X  —  CO  -.s  m  ?J  Tt 

..i  3 


'-5.5-5  Up  ; 


§ 

m 

1  so  O  O)  rt  ^  t-  C;  7-1  •.-:  X  ^  'f  -.O  CV  ?>  i-O  I-  =:  CO  -O  C-.  ?1  1-  1-  C  CO  -—  X  —  -T  t-  =  O)  O  X  —  r*  t- 

TO 

=> 

CO 

CO o ?>_■» ■* t- =  CO -.3 S5  ?J o  CO  —  JO -o  ri  o^  to  X  — -Tf »- c;  ^j  1.0  x^,-  ft~i c-. corse-., — r  r-  o 
,-,'"aa"co^ii-C<^t^3i"crT-^o^"i^o'to'  x'  C5  o  — 'co  -^  *c  f~-  x'ci  cTo'i  co'-i^^  f.- x'  ci^-^i  -^'*.-'^r^— T 

ca 

COO  cs  o<  o  x  —  -*o  Ci^oflO^x^— ^-^r— c^co^o  c;  (yi  LO^cr^.-^'^h- oco  eroo^^-i't^cicooci'M 

1-1— ir-Cr-i,-.,-ir-,r-iOI!M3^!MI4a^0^0-lCCKC0KC0C0CC^TrTr'5^^-*^ 

So 

cc-ocs'Ni.ox  —  -i-t-srrocj-Micx  —  Tit-=;cT5=c-.  c-Ji-ox rt-=:cc-.cc;o-ii.-x r 

i-f'^fcc  o'o  t-'c:'='— co'-t  o'-o  x'C5'=:"~f  — '.^'trr-Tcr  c-'— 'o^;  r:'io'«:t-^=-;=  — 'oi  -r  co  -.=' x'sT 

s 

CO  o^c^o^  i-O^x^— -^'t  t-^^co^t-^o  ■rr_o_r^oi^».'0  x^^^^ri-^t- ^_  co  ^_  c^o^*-0^x_^.—  -^  x  —  -r  t-  o  co  o 

o> 

CO  OCi^O^OCS  ?1.0_X  — •<J,t- O_C0_^O  O  «/.C  O  OJ^tO  CX-- rft- 

coo  Ci50  «0  Ut-O  CR  — lO  X_^-< -i- t-<=  CO_^t-;C  C0CCj.'>>»05^<S  O  X. — )-x^-rt-=co-.=  o 
T-1  of  oo*a  o^^-cs^c^.-^co  ■^»-o'^h-^oc~ci —^cTco  o  — '"t-^x'co  —  ^-i^..o'o  x'cTcTorjf -r  -c  t—  x'o 

%l 

------isiti^ttiiiiiaiigiiiii§liiass|- 

70 

z^^^^-mmmmmmmmMmmmm 

lj 

^^^^^mmmmmmmmmmmmmmi 

C-1 

"^^^^^^^ttSt^^lsiilS^tiiiisii^l^iliiili 

o 

--^^---t^t5^?tiiiitiiglitiisiiis^iiili 

-------I^i^i^tt^iitiiliiili5li5iii5iii 

T^ 

^^^^^mmmmmmmmmmmm^ 

p_ 

^^---mmmmMmmmm^mm^m 

^^^^^^^^mmmmmmmmmm^m 

Ss 

^^^3^5S|5i^;J55§i^5^S5t5^5g52§55S^3^5t? 

^ 

^.  •^  "-^ '■'^- "^  *^, '^.- '^^  "^.^  *", '^,  "t- ^,  ^r"-?, 'V '^. '"—-"*.  ^. '■■'.'-"*. '^,  ^- ~.^  "t 

" 

1,4 
2,7 
4,1 
5,5 
6,9 
6,2 
9,6 
11.0 
12,4 

I.'-),! 
16,5 
17,9 
19,2 
20.6 
22.0 
23.4 
24,7 
26,1 
27,5 
28,9 
30,2 
81,6 
83,0 
84.4 
85,7 
37,1 

89,9 
41,2 
42.6 
44,0 
4.5.4 
4(1.7 
48.1 
49,5 
50.9 
52,2 

C4 

1,4 
2,8 
4,1 
6,5 
6,9 
8,8 
9,7 
11,0 
12,4 
13,8 
1.5,2 
16,6 
17,9 
19,3 
20,7 
22,1 
23,5 
24,8 
26,2 
27.6 
29,0 
80,4 
81,7 
33.1 
84,5 
36,9 
87,3 
38,6 
40,0 
41,4 
42,8 
44,2 
45,5 

49.7 
51,1 
52,4 

H    O    -D         ^ 


io^ccco?rcccccccc"^'V'^'^'^'^'T"^*-'^o 


=  1:^ 


i    '   P  :   S 


,r-t"»^"rHT-<C-^010*^^C<10JC0C0C0C0C0C000TI,-^-^-^',f^'^OOO 


SUGAE. 


1025 


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o3o3Sooo3S331£Sot-?i£-?-t-t-t-;ooxcx.<»QC.a)ccccc-.o-.c-.e-.o-.c-.oja>oooo  =  o 


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1 5'S  S  2  S  S  S  S  3  S  S  S  S  i  5  S  g  Jf  ?;  S  {-SjS^figSSSSSSSgSgSgSgglllSlo 


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^T^^i^^^^.'o  CO  =  CO  o  o  «,^»  - 't•-,=^'^'''^'^:.'t-t'^.~,«  e:''r^:j':.=.2j;;.  53  :;:-s  =•  §  'i-  S«-3-S  S  S- 


SSS3gVSSS3S3§^SSf:?i?2^i2i-^iSSSa:coc^Soov<r.oo5o:oic-:  =  o  =  oe  =  3 
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H  Lo" '-o  cc' <^  o  ■>"»  CO -**" ^ H^ '>^'^ <3^ rr '?3" ^ 


S  2  3  g  g  S  S  5  S  33 -S  3 -S  S  g?i?2  .-f  g  tr  S?iSSS52g£SgSgSfec-.iioi3  =  o  =  =  =  =  ;: 


S  S  g  g  S  S'g  5  S  3  3  SV3  S  pT^'e  2:  g  5^  S  S  S  S  S  S  S  S  S  s  S  §  S  '<?.  S  c-.  S-:  =  =  =  ^  =  "=  = 


-t  t-  c  ^  >-  =  or  -^  =■-  •?'  -.^V^ '-'%  '^.  '",'^. 
cft  <=' 'm' CO -t -ii  ►-•  c/:' C-;  -  £!  CO  i£  t=  tr  £  2 

-  ~  -  -  —  c^  tr.  c-  C--  c  <r  C  O  O  C  —  ^ 


^   h3SSggSgS3333£Sg?:?iei2gt^55oSS83o6Sa.c^c-.d-.o=;c-.o;c-.oo  =  =  3  =  =  0; 


CO   -^  CO  -I""  I—  "■'>  C-.  rC!  -M  CO  -"  ■-=  t-  r^  ; 


•  gSScoccoOQCXoSc-.  C-.  c"o-.  C2  0;co  =  c^  =  2j^j 


o  oi  o  o  <N  o  ex.  CI  .o  a.  :m  o  00 «  o  cc  -,o  «  ^_^o  CO  ^^o  ain't  «i '-,'*,'»::;,  35  =5  p^-^.^.;^-^-;35JI-S2't> 


•^  t—  r-»  -^«  b-  ■^,~{'.  ^■V"". 


„  ^  r/,  ^  ^  '.r  ^  -t  cc  .-  uo  CC;  —  if:,aj_-;i.-:  -y,--, 
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22  S'S'S  2  S  3  3  3  S  S  3  S  g  ?if2  ?i2 1:  .^  a  S  S  3  S  S  S'  S  §  S  a  S  ^.  c-.  cC  o  3  =  =  =  =  o  = ;:;  - 


^ 


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lb  o  o  o  o  o  o  !0  -3  --0  o  o  cs ; 


_  _      i^o  Tf'i^.-H -rt  cfi^  »c  oc --o -/)  o-i^ic  Oicyi^tc  c:_05O  cnco_'-s  o^ 

-f  o' Is  cr'Srf  oi « -f -^'r/c^g'— 'oj -+ LO' "i^cr'c;  c^'co'-*  «  hr  ^-  <=  —  « 


Sg'gg'SgS33'3S53'Sf:^^eg£gSSSS6S5z38§.SgSfefe^.S£l  =  |2oo-;: 


o_o,co^t-^c:__'l'^t-.,— ^-*  c» -,<r;  CO  01  o.  o  e^. --=  =v«  «  =  «  ►-,<=  ^t  ►-,'-t;J.'»  ^J*- v^^,  ^  f •  '^r  ^  !f\  5  2"  ^y:  ?;  ='  §  «' 

o'3o'goSS333oo£SPS?!SgSS^Soo«SSccSoSSSo;o>c-.  c-:3aa  =  0  =  =  ;^^  — 


00  tMO  0=  CO  --o  =>  co^  o  -t »--  o  X  oi  o  c=  o.  o  o  CO  -o  o,-r  1- -  T|.^cc  r-^o,cc  01,0  «  co,o  =.co.t- o,-^,^,^,^.cc 

S3  g  g'S  g'3'3  3  S  5  5  S  ?  ?:' ?2  ^'e  l^  ^iff  S5  S.S  S  S  36  S  ?.  g  §  S  ^  S  S 1 3  a  S  ^  SSS£Hn 


12  S'S'S  S  3^3'3'3'S'3'S'g  ?f  ?S"tf  g  t^'^'S  S'S  Sf  S'S  ??  S  3.  Si  S  £  g  S  ?:  ||  ||  ||  =  ^  =  i:  - 


I  (M  O  O  CO  t—  i-"  -*  CO^^^O^C^tM  to^o^co^t-^^_*^^co_ci  10  c^co 


-to  t-^co~cr^<rT'H<'<-o  ^crcT^of  co'ic^  *r^  —  '^  iS  Z^ 

oox-oo^csciCiasCiC".  OiCsocccc  —  — »^  —  ^^ 


rj.  -x  ^1  o  --s  '-^  o  o  ^  00  ^  in  o>  OJ  o  =  m  ^  -^  o  en  01  o  o  co  t-, o^-t  cc  ot.0  =:=. «, ^J^c,"*. »-. ".  '^.  =^,'n 'f.  -. "-.  t; '_.. 

S  3  g 'is  §  3  3  3  S  !i  3  § .-' fi  ?' ii'g  S'g  S  S  S  3  S  5  S  g  3  §  S  S  S  g  S  3 1|  fe  o'gs;:r  i :: 


«.  o  -1- .-  -  ..o  «  c^^  -^  o  -t  ^  -  o  -  OJ  ts  o  -f,t-^r-. o  =n  »v"^=  t ^. '-,'^'='.=1^.  X'^!'- *"•? S  ?  2  S  o'-'^' 5  S 

gg'gS§§333'353gPef?:'.2{rSgS§SSSSSgS§?.o«o33  =  =  =  o  =  --j:-- 


S  1  S¥g  S  g  S3  3  3  3  5  3  g  if  S  ?:  S  tr  2  g  S  S  3  S  S  3g  S  S  §  §  is  5  5  g  5  3  =  -^ 


-.  c-i  ccic^  'X  c^  ^  (M  r:  --r  "^  r-  ^  —  »-  '^'-  -^  * 


3ggSg3  3333  o3t^t^i^t^t-<-'- CO  ccooccccccccc>cno-.oic=cr.cT-=v  ___  =  ___-;;- 


c,  o  o  ^  ^  o,  .o  o  eo .--  '-'^=^«'-,-,t«n»°'t«nf  =.«.-, -''is :?  S  5:-  5--  TJf-  f~  ?  5  --S  5  5  3 
3"g'Kag533'3333ggggg?-ggSSSgSg^c^a5«cr-c--  =  =  =  =  =  =gS---^- 

VOL.  III.~65 


1026 


SUGAR. 


I<X>0iC0t0Oi0h-'O^r—  -«^C0-»--IOQ0(>J»0O0^C00iC0OOC0h-O*tl-—  r-'-tcr-'-'if^ 


I-  C/J  CC  <X  iX  C/>  >XJ  O;  CV  Ol  Ci  Oi  Ci  — ■  ■3 
r-r-«r-<r-.«-"r-»-ii-<--i'-'i— '.-.^O.IC^G.l^JOl'MCMOI 


'»^tOh-c/>CsO<--0*CO-^*OtO 


^  Oi  O  T-  Ol  CO  "^  I. 


■XC:Oi-H(01CO'^tCtO»^GOasO» 


*<,CC'Cf)cOaOaDCsOiCacic.  CiOiOiOiOsOOOO  —  OOOOC:^T-'r-,^,-.,-.^-,_»-.r-c-l 


JCO-tiCtOI^CCOiO 


I  ^'^,*^'^.— r^  — ,**,  ^'^^,^r^*^^'^,'^,'-'^,'*l.'~t^  ^,^. '^. 't-^.  — ,-'  ^"    -'"    -  Ot  to  CI  -^  -T)"  t— Cl  C^  »C  b-  O  CO  to  X  1— 

'  I— Ci  o  *-^  co'-t  o'to'i— C4  o"'-rco'**i^o't— 00  of  o's-i'co  Tf  id  t^c/j  Oi  — 'oi  c-t  ■^'  tc'i-  rrjcT-^  c-t  co't'^'j— ct'o  ^e>J  a'>"»'^' 
o  o  ^  T--  !-■  1-"  "  ^  T-i  "  01  c-i  c^  c^  G^  c^  oi  c^  CO  CO  CO  c-i.  CO  cC'  CO  CO  -r  -r  ^r  4  -T  'Tt  Tj<  rr  ic  »o  ic  Ji::  ic  iC  ^ 


I  "^tO^O>_ri_>r^b-C:^cr  tO^  "/:  ^^-^_l-^Oi^01^0_CC  O  CO^tO^Ci  i— ^-^^^l-^O^OJ^O^X -r- CO  tO^Ci^i^J^Tt*  t-OCO»COO,-f<J*tDCSC^tOb- 
QtrcTcTs^CO  ■^to'  t-^  X  Ca  — 'oi  CO -t"tO  f-^iX  O  '-^orco'*c"co'»~^cf  O  i-for-^i-t' to  I— cf  cTt-Ti^  Tf  *c  ^(x'cf  o  '-^o~'"*rir 

o  0'-Hi-i<-Hi-.T-«T--i»-H"Oiojo)oic^oioJcocococococococo'r-^'^'TfTj4-Tr-rj'Tfioif^iOir^jOiCiC»ctctotototc 


)  tOO^O^^-^^b-^OCOO^CC  i-Hl.'0t>^O'yiii0C0--__rH^t0  Ci  (N  tC  -X  O  CO  to 

r^of-^'o  to -yjci  o -^co -t  jo  b-^rAci  o  ofc? '^idb-i'x'cf -^  oi  oi  -,  —  .     -   _.     -.  ..  - 

■  —  —  —  'MOJC'IO*COCOC.''COCOCOCOCO'^'^*rTrT}''»f»r-^*C»C»C*.'^»OiiO»f2tOtCtOtO!: 


109,2 
1 10,5 
111,8 
113,1 
114.4 
11.5,0 
1169 
118,2 
119,5 
120,8 
1-2-2,1 
1-23,4 
1-24,0 
1-25,9 
127,2 
128,5 
129,8 
131,1 
132,4 
133,0 
134.9 
136,2 
137,5 
138,8 
140,1 
141.3 
142.6 
143.9 
14,5.2 
146.5 
147,8 
149,1 
1.50,3 
151,6 
1.52  9 
1.54,2 
1.55,5 
156,8 
1.58.0 
1.59,3 
160.6 
101,9 
163.2 
164,5 
16.5,8 
167,0 

3 

109,7 
111,0 
11-2,3 
113,6 
114,9 
116,2 
117,5 
118.8 
120,1 
121,4 
1-22,6 
123,9 
125.2 
126.5 
127,8 
129,0 
130.3 
131.6 
13-2,9 

135,4 
136,7 
138,0 
139,3 
140,6 
141.9 
143,2 
144.5 
1-1.5,8 
147.1 
148.3 
149.6 
150,9 
1.52.2 
1.53,5 
154,8 
156.1 
157.4 
1.58.7 
160,0 
161,2 
16'2.5 
163,8 
16.5.1 
166.4 
167.7 

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to  o  ■yii^  Gc  ■»-<  •^h-;Ocotocs<OJiiOcr>ocC' 

t— *  x'  cT  *— '  of  -t  »iO*  to*  X*  O:'  cT  r-  CO  *t  »C  1-^  x' 

_.._,_  -r  -r  »c  iO  tfi »-~  ift; ».':  "C  tc  to  to  to  to  to  t£f  o 


I  1.0  'X  -^  -t  b-  Cr  CO  to  "^'^^^'^CC '~1*^*-^  — .  •v'"^^'^1'^  '-'l'~t"^..*~ '^'^,^,'-^'^1*''^,  '^, '^ 't.  *^ '^. '^  to  CS  C^^iO  GOt-<  Tf-b^O 

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-  tJ*  T^  --f  -r  M"  -r  tc  *o  lO  if^  *r:  »o  jC:  i 


r  o  to  to  to  to  to 


O  OI  O  X  — *  ■+  f-  '-^  "^  ^-  O^CO  tO^Ci  O)  OCO  —  "^,b^  O^  0?  tO^  CS  Ol  iO  X^O-l  O  GO  1—  Tf  t-  O  CO  tO^C:  Ol».0Q0i-H'-f«b-OC0t0 

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:totr:totototcb-t 


I  o  cj  CO  to  Ci  oi  to  Ci  o^  t-O  oi^oi  o  X  '?',»o^^''^'-t»^,^'^.  *^,'-'^,"-l'^J"-:.'^  ■^,'^  —,'*,'■',— ^'^  *^ — 

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co  t-  o  CO  t—  ; 


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C0e0C0C0C0'^"*-^-f'^*t'<tM'iOOi>0»f0O»Cii0t0t0^tDtOt0t0t0l-l-t- 

110,2 
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117,9 

iiy,8 

120.0 

124,6 

127.3 
128,0 

131,3 

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135,3 
136,7 
138.0 
1.19,4 
140.7 
142,0 
143.4 
144,7 
146,1 
147,4 
148,7 
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151,4 
1.52,8 
1.54,1 
1.55,4 
156.9 
158,1 
1.59,5 
160,8 
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1(13.5 
164,8 
166.2 
167.5 
16s,8 
170,2 
171,5 
17-2,9 
174.2 

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SUGAE. 


1027 


Fehling  has  reduced  this  to  a  quantitative  test,  and  makes  a  solution  of  copper,  that  will 
keep  permanently.     This  is  seen  by  the  following : — 
40  grammes  of  sulphate  of  copper, 

IGO  grammes  of  neutral  tartrate  of  potassa,  or  200  grammes  of  tartrate  of  soda, 
dissolved  and  added  to 
700 — 800  cul).  c.  (grammes)  of  caustic  soda,  specific  gravity  1"12. 
This  is  diluted  with  water  to  11 54 '5  cub.  c. 
Of  this  solution  1  cub.  c.  =  O'OOSO  grape  sugar,  or 

0"00475  cane  sugar. 
Grains  may  be  used  instead  of  graromes,  and  then  1  grain  =  00050  grape  sugar,  without 
change  of  calculation. 

100  parts  of  grape  sugar,  "         *         '        ) 

95       "        cane  sugar,  -         -         -        V  =  220-5  CuO,  or  198  Cu'O, 

90       "        starch,  .         .         .         .        ) 

Urine  may  be  tested  with  this.  It  should  be  first  diluted  10  to  20  times  with  water; 
when  the  test  is  added,  it  should  be  boiled  a  few  seconds,  when  the  suboxide  of  copper  falls. 
Very  constant  results  may  be  obtained. 

Caramelin  is  the  name  given  by  E.  Maumene  to  a  brown  substance,  insoluble  in  acids 

and  alkalies,  which  is  produced  by  evaporating  sugar  with  fifteen  to  thirty  times  its  weight 

of  chloride  of  tin,  and  heating  it  to  about  220°  Fahr.     It  is  C'^H^O'*,  and  being  constant  has 

been  proposed  by  him  to  be  used  as  a  test  of  the  presence  and  quantity  of  sugar. 

Horsley  detects  minute  quantities  of  sugar  by  means  of  chromate  of  potash. 

Sugar  Refinings. — The  raw  or  Muscovado  sugar,  as  usually  imported,  is  not  in  a  state 


1028 


SUGAE. 


of  sufficient  purity  for  use.  The  sugar  is  blended  with  more  or  less  of  fruit  and  grape 
sugars,  with  sand  and  clay,  with  albuminous  and  coloring  matter,  chiefly  caramel.  To 
separate  the  pure  sugar,  the  plan  formerly  adopted  was  to  add  blood,  eggs,  and  lime-water 
to  a  solution  of  the  raw  sugar,  and  after  applying  heat,  to  remove  the  thick  scum  of  coagu- 
lated albumen,  which  also  removed  a  considerable  portion  of  coloring  matter.  The  clear 
liquid  was  concentrated,  and  the  semi-crystalline  mass  being  placed  in  conical  moulds,  as 
much  of  the  molasses  as  would  drain  by  gravitation  was  allowed  to  escape  from  the  points 
of  the  moulds,  and  the  remainder  was  expelled  by  allowing  water  or  a  solution  of  pure 
sugar  to  tiickle  through  the  mass  of  crystals.  The  loaves,  being  trimmed  into  shape  and 
dried,  were  lit  for  sale. 

By  this  process  only  a  small  proportion  of  the  sugar  was  made  into  loaf.  The  method 
of  removing  the  coloring  matter  was  crude,  imperfect,  and  expensive,  and  the  high  tempera- 
ture requisite  for  the  fermentation  of  the  syruji  not  only  injured  its  color,  but  converted 
a  large  proportion  of  the  sugar  into  the  uncrystallizable  variety. 

These  defects  were  remedied,  to  a  great  extent,  by  the  adoption  of  Howard's  vacuum 
pan,  for  the  concentration  of  syrups  under  diminished  atmospheric  pressure,  and  conse- 
quently at  a  low  temperature,  together  with  the  use  of  filtering  beds  of  animal  charcoal  for 
the  removal  of  coloring  matter. 

There  are  three  classes  of  sugar  refineries  in  this  country,  the  chief  productions  of  which 
are  respectively :  — 

1st.  Loaf  sugar. 

2d.  Crystals,  («.  c.  large,  well-formed,  dry  white  crystals  of  sugar.) 

3d.   Crushed  sugar. 


L^.}i 


SUGAR. 


1029 


G?,\ 


In  the  former  two,  good  West  India,  Ilavunna,  JIauritius,  or  Java  sugar  are  almost 
exclusively  used.  In  the  last,  all  clashes  of  sugar  are  indiscriminately  employed.  The 
manufacture  of  loaf  sugar  is  chietly  carried  on  in  London  ;  of  crystals,  in  Bristol  and  Man- 
chester;  of  crushed  sugar,  in  Liverpool,  (ireenock,  and  Glasgow.  Besides  these  places, 
which  are  the  chief  seats  of  the  sugar-retining  trades,  this  branch  of  industry  is  carried  on 
more  or  less  at  Plymouth,  Southampton,  (ioole,  Sheffield,  Newton,  (Lancashire,)  and  Leith. 
The  methods  vary  a  little  in  different  retineries,  but  the  following  description  refers  to  the 
most  modern  and  best  conducted  which  are  to  be  found  in  this  country.  The  general 
arrangements  of  a  sugar  house  are  shown  inp'(/,s.  029  and  tiSn. 

Loaf  Sl'Gar. — Solution.  The  raw  sugar  is  emptied  from  the  hogsheads,  boxes,  or 
mats,  as  the  case  may  be,  and  discharged  through  a  grating  in  the  floor  into  a  copper  pan, 
about  8  feet  in  diameter.  This  dissolving  pan  is  sometimes,  although  incorrectly,  called  a 
defecator;  it  was  formerly  called  a  blow-up,  from  the  practice  of  blowing  steam  into  it, 
but  the  practice  and  the  name  are  now  antiquated.  Hot  water  is  added,  and  the  solution  is 
lacilitated  by  the  action  of  an  agitator,  or  stirrer,  kept  in  motion  by  the  steam-engine. 
The  proportions  of  sugar  and  water  are  regulated  so  that  the  liquid  attains  a  specific  gravity 
of  about  1'250  or  29°  Baume,  as  a  higher  density  than  this  would  interfere  with  subsequent 
processes.  A  copper  coil  or  casing  to  the  pan,  heated  by  steam,  furnishes  the  means  of 
raising  the  liquid  to  a  temperature  of  165°.  The  plan  of  boiling  the  "  liquid"  is  becoming 
gradually  disused.  If  the  solution  is  acid,  sufficient  lime-water  is  added  to  make  it  neutral. 
The  use  of  blood,  which  was  formerly  added  at  this  stage,  is  in  most  cases  dispensed  with ; 
the  advantage  arising  from  its  use  is  readily  obtained  from  the  employment  of  an  increased 
amount  of  animal  charcoal  in  a  suVjsequent  process,  while  the  mischief  arising  from  the 
introduction  of  nitrogenous  matter  so  prone  to  decompose  is  avoided.  Some  machinery  is 
used  for  crushing  the  hard  lumps  to  facilitate  .solution. 

Removal  of  insoluble  matter. — The  liquor  having  been  brought  to  the  requisite  density 
and  temperature,  and  also  being  perfectly  neutral,  is  passed  through  the  bag  filter. 

The  apparatus  consists  of  an  upright  square  iron  or  copper  case,  a,  a,  Jig.  631,  about  6 
or  8  feet  high,  furnished  with  doors  ;  beneath  is  a  cistern  with  a  pipe 
for  receiving  and  carrying  off  the  filtered  liquor ;  and  above  the  case 
is  another  cistern  c.  Into  the  upper  cistern  the  syrup  is  introduced, 
and  passes  thence  into  the  mouths  e,  e,  of  the  several  filters,  d,  d. 
Thes3  consist  each  of  a  bag  of  thick  twilled  cotton  cloth,  about  two 
feet  in  diameter,  and  6  or  8  feet  long,  which  is  inserted  into  a  narrow 
"  sheath,"  or  bottomless  bag  of  canvas,  about  5  inches  in  diameter,  for 
the  purpose  of  folding  the  filter-bag  up  into  a  small  space,  and  thus 
enabling  a  great  extent  of  filtering  surfaces  to  be  compressed  into  one 
box.  The  orifice  of  each  compound  bag  is  tied  round  a  conical  brass 
mouth-piece  or  nozzle  c,  which  screws  tight  into  a  corresponding  open- 
ing in  the  bottom  of  the  upper  cistern.  From  40  to  400  l)ags  are 
mounted  in  each  filter  case.  The  liquor  which  first  passes  is  generally 
turbid,  and  must  be  pumped  back  into  the  upper  cistern  for  refiltration. 
The  interior  of  the  case  is  furnished  with  a  pipe  for  injecting  steam, 
which  is  occasionally  used  for  warming  the  case.  Fig.  632  shows  one 
mode  of  forming  the  funnel-shaped  nozzles  of  the  bags,  in  which  they 
are  fixed  by  a  bayonet  catch.  Fig.  633  shows  the  same  made  fast  by 
means  of  a  screwed  cap,  which  is  more  secure. 

When  the  bags  are  fouled  from  the  accumulation  of  clay  and  a 
slimy  substance  on  their  inner  surfaces,  the  filter  is  unpacked,  the  bags 
withdrawn  from  the  sheaths,  and  well  wa.shed  in  hot  water.  This  wash- 
ing is  usually  performed  with  a  dash-wlieel,  or  some  one  of  the  numer- 
ous kinds  of  washing-machines  now  in  use.  Perhaps  that  of  Manlove 
k  Alliott,  of  Nottingham,  is  in  greatest  favor.  The  dirty  water,  with 
the  addition  of  a  little  lime,  is  smartly  boiled,  and  after  some  hours 
being  allowed  for  subsidence,  the  supernatant,  clear,  weak  solution  of 
sugar  is  removed  and  used  in  the  first  process,  (solution,)  while  the 
muddy  residue  is  placed  in  canvas  l)ags  and  subjected  to  pressure.  The 
residue,  technically  called  scum,  is  tin-own  away. 

lienioval  of  color. — The  liriuor  issuing  from  the  bag-filters  generally  resembles  in  color 
dirk  sherry  wine.  To  render  this  colorless,  it  is  passed  through  deej)  fiitcring-lieds  of  granu- 
lated burnt  bones  or  animal  charcoal.  When  this  substance  was  first  introduced,  beds  of  a 
few  inches  in  depth  were  considered  sufficient,  l)\it  the  quantity  of  cliarcoal  used  per  ton 
of  sugar  has  steadily  increased,  and  filters  of  no  less  a  depth  than  50  feet  are  now  some- 
times used. 

Cylinders  of  wrought  or  cast  iron,  varying  in  diameter  from  5  to  10  feet,  and  in  height 
from  10  to  50,  having  a  perforated  false  bottom,  a  couple  of  inches  above  the  true  one, 
are  filled  with  granulated  animal  charcoal. 


1030 


SUGAE. 


The  grain  varies  from  the  size  of  a  turnip-seed  to  that  of  peas,  some  refiners  preferring 
it  fine,  and  others  coarse. 

Liquor  from  the  bag-filters  is  vmi  on  to  the  charcoal  till  the  cylinder  is  perfectly  filled, 
when  the  exit-tap  at  the  botiuiii  is  opened,  and  a  stream  of  dense  saccharine  fluid,  perfectly 
colorless,  issues  i'orth.  The  amount  of  sugar  which  the  charcoal  will  discolor  depends  upon 
the  age  and  composition  cf  the  charcoal,  the  degree  of  perfection  with  which  the  previous 
revivification  has  been  performed,  and  the  quality,  color,  and  density  of  the  liquor  to  be 
operated  upon.  One  ton  of  charcoal  is  sometimes  used  to  purify  two  tons  of  sugar ;  and 
in  at  least  one  refinery,  where  inferior  sugar  is  operated  on,  two  tons  of  charcoal  serve  for 
one  ton  of  sugar.  In  most  provincial  refineries  about  one  ton  of  charcoal  is  used  to  one 
of  sugar ;  but  in  London,  from  the  dearness  of  fuel  and  other  causes,  a  smaller  proportion 
of  charcoal  is  employed.  The  liquor  from  the  charcoal  filter,  at  first  colorless,  becomes 
slightly  tinged,  and  in  course  of  time,  varying  from  24  hours  to  72,  the  power  of  the  char- 
coal becomes  exhausted,  the  partially  decolored  syrup  is  passed  through  a  fresh  charcoal 
filter,  and  the  sugar  is  washed  out  from  the  charcoal  by  means  of  hot  water.  The  charcoal 
is  ready  to  be  removed  for  revivification,  which  process  is  treated  of  farther  on. 

Concentration. — The  next  process  in  sugar-refining  is  the  evaporation  of  the  clarified 
syrup  to  the  granulating  or  crystallizing  point.  The  more  rapidly  this  is  effected,  and  the 
less  the  heat  to  which  it  is  subjected,  the  better  and  greater  is  the  product  in  sugar-loaves. 
No  apparatus  answers  the  refiner's  double  purpose  of  safety  and  expedition  as  well  as  the 
vacuum-pan. 

The  vacuum-pan,  invented  by  Howard,  and  patented  in  the  year  1812,  is  an  enclosed 
copper  vessel,  heated  by  steam,  passing  through  one  or  more  copper  coils,  and  a  steam- 
jacket.  The  vapor  arising  from  the  boiling  solution  of  sugar  is  condensed  by  an  injection 
of  cold  water,  the  arrangement  of  which,  and  the  maintenance  of  a  vacuum,  closely  resem- 
ble the  condenser,  injection,  and  air-pump  of  an  ordinary  condensing  steam-engine. 

Fig.  634  shows  the  structure  of  a  single  vacuum-pan.     The  horizontal  diameter  of  the 


copper  spheroid  c  c  is  from  7  to  10  feet ;  the  depth  of  the  under  hemisphere  A  is  at  least 
2  feet  from  the  level  of  the  flange  ;  and  the  height  of  the  dome-cover  is  from  3  to  5  feet. 
The  two  hemispheres  (of  which  the  iuferioi'  one  is  double,  or  has  a  steam-jacket)  are  put 
together  by  bolts  and  screws,  to  preserve  the  joints  tight  against  atmospheric  pressure. 

The  steam  enters  through  the  valve  f,  travei-sing  the  copper  coil  d,  and  filling  the  steam- 
jacket,  the  condensed  water  issuing  from  a  small  pipe  below,  c  represents  the  dome  of  the 
vacuum-pan,  the  vapor  from  which  passing  in  the  direction  of  N,  allows  any  particles  of 
sugar  carried  over  by  the  violence  of  the  ebullition  to  be  deposited  in  the  receiver  m. 


SUGAR. 


1031 


The  vapor  is  condensed  by  jets  of  cold  water  issuing  from  a  perforated  pipe,  and  the 
water,  uncondensed  vapor,  and  air  are  removed  by  the  action  of  a  powerful  air-pump,  l  is 
the  measure  cistern,  from  which  the  successive  charges  are  admitted  into  the  pan  ;  i  and  k 
represent  respectively  a  thermometer  and  a  barometer,  the  former  being  required  to  indicate 
tiie  temperature  of  the  boiling  syrup,  and  the  latter  the  diminished  atmospheric  pressure 
within  the  pan.  p  is  the  discharge-cock,  and  ii,  the  proof-stick,  is  an  ajjparatus  inserted  air- 
tight into  the  cover  of  the  vacuum-pan,  and  which  dips  down  into  the  syrup,  serving  to  take 
out  a  sample  of  it,  witliout  allowing 


036 


635 


air  to  enter.  It  is  shown  in  detail 
hy  fig.  039,  which  rejjresents  a  cylin- 
drical rod,  capable  of  being  screwed 
air-tight  into  the  pan  in  an  oblique 
direction  downward.  The  upper  or 
exterior  end  is  open ;  the  under, 
which  dips  into  the  syrup,  is  closed, 
and  has  on  one  side  a  slit  a  {fif/s. 
636,  639),  or  notch,  about  i  in.  wide. 
In  this  external  tube  there  is  another 
shorter  tube  b,  capable  of  moving 
round  it,  through  an  area  of  180°. 
An  opening  upon  the  under  end  c 
corresponds  with  the  slit  in  the  outer  '^  cl|r 
tube,  so  that  both  may  be  made  to  L''^- 
coincide.  Jig.  635,  a.  A  plug  d  is 
put  in  the  interior  tube,  but  so  as  not  to  shut  it  entirely.  Upon  the  upper  end  there  is  a 
projection  or  pin,  which  catches  in  a  slit  of  the  inner  tube,  hj  which  this  may  be  turned 
round  at  pleasure.  In  the  lower  end  of  the  plug  there  is  a  hole  e,  which  can  be  placed  in 
communication  with  the  lateral  openings  in  both  tubes.  Hence  it  is  possible,  when  the  plug 
and  the  inner  tube  are  brought  into  the  proper  position,  a, /i^.  635,  to  fill  the  cavity  of  tho 
rod  with  the  syrup,  and  to  take  it  out  without  allowing  any  air  to  enter.  In  order  to  facili- 
tate the  turning  of  the  inner  tube  within  the  outer,  there  is  a  groove  in  the  under  part,  into 
which  a  little  grease  may  be  introduced. 

Whenever  a  proof  has  been  taken,  the  plug  must  be  placed  in  reference  to  the  inner 
tube,  as  shown  in  fig.  035,  c,  and  then  turned  into  the  position  a  ;  when  the  cavity  of  the 
plug  will  again  be  filled  with  syrup,  c  must  be  now  turned  back  to  the  former  position, 
whereby  all  intercourse  with  the  vacuum-pan  is  cut  off;  the  plug  being  drawn  out  a  little, 
and  placed  out  of  communication  with  the  inner  tube.  The  plug  is  then  turned  into  the 
•position  D,  drawn  out,  and  the  proof  examined  by  tlie  fingers. 

The  method  of  using  the  vacuum-pan  varies  with  tlie  character  of  the  grain  required  to 
be  produced.  On  commencing  boiling,  the  syrup  should  be  run  in  as  quickly  as  possible, 
till  the  whole  heating  surface  is  covered,  when  the  steam  is  turned  on,  and  the  evaporation 
conducted  at  a  temperature  of  from  170'  to  130'  Fahr.  As  soon  as  the  syrup  begins  to 
granulate,  the  temperature  becomes  reduced  to  100';  and  finally,  just  before  the  evaporation 
is  completed,  and  the  sugar  ready  to  be  discharged  into  the  heater,  it  is  further  reduced, 
and  approaches  145',  being  the  lowest  temperature  at  which  proof  sugar  boils,  3  inches 
from  a  perfect  vacuum.  When  the  sugar-boiler  ascertains,  by  withdrawing  a  sample  of  the 
syrup  by  means  of  the  proof-stick,  and  examining  it  against  the  light  between  his  finger  and 
thumb,  that  the  crystals  are  in  a  sufficiently  forward  state  for  his  purposes,  he  adds  another 
measure  full  to  that  already  in  the  pan,  and  the  same  process  is  repeated  till  the  whole  charge 
has  been  admitted.  After  each  successive  charge  the  cr)'stals  continue  increasing  in  size  to 
tho  end  of  the  operation,  those  first  formed  acting  as  nuclei ;  a  skip,  as  it  is  technically  called, 
or  a  panful  of  the  concentrated  sugar,  may  be  made  in  from  two  to  four  hours  from  the 
commencement  of  the  boiling.  If  a  fine  grain  sugar  be  required,  greater  (luantitics  of  syrup 
are  admitted  at  each  charge  of  the  measure,  and  vice  vemd. 

Making  of  loaf  sugar. — The  proof  sugar,  at  a  temperature  not  exceeding  145",  is  then 
let  •  down  through  a  cock  or  valve  in  the  bottom  of  the  pan  into  the  heater.  The  sugar 
liquor  consists,  at  this  stage  of  the  process,  of  a  large  number  of  small  crystals  floating  in  a 
medium  of  syrup. 

Tiie  heater  is  an  open  copper  pan  of  about  the  same  capacity  as  the  vacuum-pan,  and  is 
furnished  with  a  steam-jacket  and  provided  with  an  agitator — in  fact,  it  closely  resembles 
the  dissolving-pah  used  for  the  first  process.  The  o))ject  to  be  attained  in  the  heater  is  to 
raise  the  sugar  to  a  temperature  of  180',  which  has  been  found  by  practice  to  be  the  point 
best  adapted  for  hardening  aiul  completing  the  formation  of  the  crystals,  during  which  pro- 
cess tlie  sugar  is  constantly  stirred. 

The  sugar  is  then  run  out  through  a  cock  in  the  bottom  of  the  heater  into  a  ladle,  from 
whence  it  is  poured  into  moulds  or  cones  of  sheet  iron  strongly  painted.  The  sizes  of  the 
moulds  vary,  from  a  capacity  of  10  pound  loaves  to  that  of  56  pound  baatards — a  kind  of 


1032  SUGAR. 

soft  brown  sugar  obtained  by  the  concentration  of  the  inferior  syrups.  These  moulds  have 
tlic  orifices  at  their  tips  closed  with  nails  inserted  through  pieces  of  cloth  or  india-rubber, 
and  are  set  up  in  rows  close  to  each  other,  in  an  apartment  adjoining  the  heaters.  Here 
tlicy  are  left  several  hours,  commonly  the  whole  night,  after  being  filled,  till  their  contents 
become  solid,  and  they  are  lifted  next  morning  into  an  upper  floor,  kept  at  a  temperature 
of  about  100°  by  means  of  steam-pipes,  and  placed  over  gutters  to  receive  the  syrup  drain- 
ings — the  plugs  being  first  removed,  and  a  steel  wire,  called  a  piercer,  being  thrust  up  to 
clear  away  any  concretion  from  the  tip.  The  syrup  which  flows  oft'  spontaneously  is  called 
green  syrup.  It  is  kept  separate.  In  the  course  of  one  or  two  days,  when  the  drainage  is 
nearly  complete,  some  finely  clarified  syrup,  made  from  a  filtered  solution  of  fine  raw  sugar, 
is  poured  to  the  di'iith  of  aljout  an  inch  upon  the  base  of  each  cone,  the  surface  having  been 
previously  rendered  level  and  solid  l)y  an  iron  tool,  called  a  bottoming  trowel.  The  liquor, 
in  percolating  downward,  being  already  a  saturated  syrup,  can  dissolve  none  of  the  crystal- 
line sugar,  but  only  the  colored  matter  and  molasses  ;  whereby,  at  each  successive  liquoring, 
the  loaf  becomes  whiter,  from  the  base  to  the  apex. 

To  economize  the  quantity  of  "  tine  liquor"  used,  it  is  usual  to  give  a  first  and  even  a  second 
liquor  of  an  inferior  quality  before  applying  the  finishing  liquor,  which  is  a  dense  and  almost 
saturated  solution  of  fine  sugar  absolutely  free  from  color.  A  few  moulds,  taken  promiscu- 
ously, are  cmi)tiod  from  time  to  time,  to  inspect  the  progress  of  the  blanching  operation  ; 
and  when  the  loaves  a])pear  to  have  acquired  as  nmch  color,  according  to  the  language  of 
refiners,  as  is  wanted  for  the  particular  market,  they  are  removed  from  the  moulds,  turned 
on  a  lathe  at  the  tips,  if  necessary,  .set  for  a  short  time  upon  their  bases,  to  diffuse  their 
moisture  equally  through  them,  and  then  transferred  into  a  stove  heated  to  ISO  or  140"  by 
steani-pipes,  where  they  are  allowed  to  remain  for  two  or  three  days,  till  they  are  baked 
thoroughly  dry.     They  are  then  taken  out  of  the  stove,  and  put  up  in  paper  for  sale. 

In  the  above  description  of  sugar-refining,  nothing  is  said  of  the  process  of  claying 
loaves,  because  it  is  now  nearly  abandoned  in  all  well-appointed  sugar-houses. 

The  drainage  of  the  last  portion  of  the  liquor  from  the  moulds  is  sometimes  accelerated 
by  means  of  a  vacuum.  Centrifugal  action  has  been  also  proposed  for  this  purpose,  but  has 
not  been  found  to  succeed. 

The  drainings  from  the  moulds  which  are  collected  in  gutters  and  run  into  cisterns  arc 
boiled,  and  form  an  inferior  quality  of  sugar.  The  drainings  from  this  last  sugar  consist  of 
treacle  or  syrup,  which  is  always  obtained  as  a  final  product. 

Manufacture  of  crijstals. — The  use  of  centrifugal  action  for  the  separation  of  liquids 
and  solids  has  been  adopted  in  the  arts  for  many  years ;  its  application  for  the  separation 
of  syrup  and  sugar  occurred  to  several  individuals,  but  it  was  best  effected  by  means  of  the 
admirable  hydro-extractor,  invented  and  patented  by  Manlove  &  Alliott,  of  Nottingham. 
Various  modifications  of  this  machine  have  been  proposed  and  patented,  but  it  is  very  doubt- 
ful whether  any  thing  that  has  been  devised  has  improved  upon  the  original  machine.  It 
would  be  tedious  and  unnecessary  to  detail  the  list  of  so-called  improvements. 

(Considerable  value,  however,  has  been  supposed  to  attach  to  the  use  of  a  blast  of  steam 
to  free  the  meshes  of  the  revolving  cylinder  from  the  semi-crystalline  syrup.  This  plan  was 
the  subject  of  a  patent  granted  to  the  late  C.  W.  Finzel,  but  the  opinion  of  those  who  con- 
sider that  the  injurious  action  of  a  blast  of  open  steam  upon  the  .'^yrup  far  outweighs  the 
advantage  arising  from  a  machine  so  easily  cleansed,  is  gaining  ground  daily. 

In  the  manufacture  of  "crystals,"  sometimes  called  centrifugal  sugar,  all  the  earlier  pro- 
cesses previous  to  boiling  are  conducted  as  already  described. 

Covcentration. — It  is  found  more  convenient  to  make  use  of  vacuum-pans  of  large 
dimensions,  and  provided  with  extra  heating  surfiice  by  the  introduction  of  several  addi- 
tional coils.  The  object  sought  to  be  obtained  is  the  formation  of  large  crystals,  which  is 
effected  as  follows  : — The  pan  is  partially  filled  with  liquor  ;  this  is  concentrated  until  minute 
crystals  appear;  a  further  portion  of  liquor  is  added  — the  concentration  continued — more 
li(|iior  and  further  concentration  again  and  again — imtil  the  pan  is  filled  ;  the  object  being 
to  keep  the  motlur-lhjuor  sufficiently  fluid  to  prevent  the  formation  of  a  second  crop  of 
crystals,  aiid  yet  sufficiently  dense  to  feed  the  crystals  already  formed.  One-half  the  con- 
tents of  the  pan  is  discharged  into  the  heater,  while  the  remaining  half  is  retained  as  a 
iniclcus,  and  the  pan  charged  as  before.      This  process  is  sometimes  repeated  several  times. 

Separation  of  cri//;tals. — The  semi-flnid  mass  is  removed  to  the  centrifugal  machines 
with  the  least  possible  delay,  and  each  machine  bnrely  attains  its  maxinnnu  speed  before 
the  syrup  is  discharged.  To  cleanse  the  surface  of  the  crystals,  they  are  washed  with  liquor, 
sprinkled  in  the  machine  by  means  of  a  watering-can,  a  few  pints  of  liquor  being  used  to 
each  cwt. 

Hy  this  process  the  percentage  of  sugar  obtained  from  the  first  and  each  separate  crys- 
tallization is  considerably  less  than  that  obtained  in  the  making  of  loaf-sugar  or  the  ordi- 
nary method  of  making  "  cnished,"  though  the  tofa/  product  does  not  vary  materially,  being 
rather  more  than  that  of  the  former  where  the  product  is  stove-dried,  and  l(>ss  than  the  lat- 
ter, which  is  sold  damp.     The  drainage  is  diluted,  filtered  through  animal  charcoal,  boiled, 


SUGAR.  1033 

and  passed  lhroun;h  the  centrifugal  machines,  and  results  in  a  second  quality  of  sugar,  tlie 
crystals  being  smaller.  The  drainage  from  this  is  treated  in  a  similar  manner,  and  a  third 
quality  of  crystals  is  the  result.  A  fourth  quality  of  crystals  is  also  sometimes  obtained, 
the  drainage  from  which  is  again  boiled  and  laid  aside  in  large  moulds  to  crystallize  for  about 
a  week,  when  treacle  and  a  low  quality  of  "  pieces"  are  the  final  result.  The  drainages  are 
sometimes  filtered  along  with  inferior  qualities  of  raw  sugar. 

The  ditfieulty  with  which  these  large  and  beautiful  crystals  obtained  by  this  process  dis- 
solve, is  an  obstacle  to  their  extensive  consumption. 

C'riisfied  su(/a): — This  process  closely  resembles  the  manufacture  of  loaf-sugar,  but  the 
raw  sugar  used  is  generally  of  an  inferior  quality.  The  filtration  through  the  animal  char- 
coal is  in  consequence  not  so  perfect ;  the  concentration  rescnibleg  that  of  loafsugar,  but 
the  use  of  a  heater  is  dispensed  with,  and  the  process  of  liquoring  is  also  dispensed  with 
where  practicable.  The  first  crystallization  is  called  "  crushed,"  and  the  second  "  pieces," 
the  drainage  from  which  goes  by  the  name  of  "  syrup."  When  this  syrup  is  diluted,  filtered 
through  animal  charcoal,  and  concentrated,  it  is  called  "golden  syrup." 

Trca'iiietit  of  vioiasses. — Foreign  and  colonial  molasses,  containing  a  large  proportion 
of  crystallizable  sugar,  are  purchased  by  refiners.  The  Muscovado  molasses  from  Cuba, 
from  Porto  Rico,  Antigua,  and  Barbadoes,  are  esteemed  the  best,  but  the  quality  of  molas- 
ses deteriorates  as  improvements  in  the  manufacture  of  sugar  are  introduced  on  the  planta- 
tions. The  treatment  of  molasses  formerly  was  simple ;  it  was  merely  concentrated  and 
allowed  to  stand  for  several  weeks  in  large  moulds  to  drain.  The  liquid  was  sold  as  treacle, 
aad  the  impure  soft,  dark  sugar,  called  bastards,  found  a  market  amorr^st  the  poorer  classes, 
especially  in  Ireland. 

The  more  recent  and  better  plan  is  to  dilute  the  molasses,  filter  it  through  animal  char- 
coal, and  concentrate  to  the  crystalHzing  point,  but  without  forming  crystals.  This  readily 
crystallizes  in  the  moulds,  and  in  place  of  the  bastards  and  treacle  a  bright  yellov/  sugar  and 
a  fair  quality  of  syrup  are  the  result.  Good  molasses  yields  40  per  cent,  sugar,  40  per  cent, 
syrup,  the  remaining  20  per  cent,  being  water,  dirt,  and  loss. 

Palm  or  Date  Sugar. — Many  trees  of  the  palm  tribe  yield  a  copious  supply  of  sweet 
juice,  which,  when  boiled  down,  gives  a  dark  brown  deliquescent  raw  sugar,  called  in  India 
jaggery.  The  wild  date  palm  and  the  gommuto  palm  yield  the  largest  proportion  of  this 
kind  of  sugar,  which  is  chemically  identical  with  the  sugar  from  the  cane,  though  the  crude- 
uoss  of  the  manufacture  is  very  injurious  to  it,  and  causes  a  large  proportion  to  assume  the 
uncrystallizable  condition.  One-twenty-fourth  of  all  the  caue  sugar  extracted  for  useful  pur- 
poses is  obtained  from  the  palm-tree. 

Bket-root  Sugar. — The  extraction  of  sugar  from  beet  root,  which  has  become  an  im- 
portant manufacture  in  several  countries  on  the  continent,  especially  in  France  and  Ger- 
many, was  developed  in  consequence  of  the  difficulty  of  obtaining  colonial  sugar  in  France 
during  the  blockade  in  the  time  of  Napoleon  I.  The  high  price  of  sugar  (5?.  per  lb.)  was 
not  the  only  stimulus  to  invention,  as  a  prize  of  a  million  of  francs  was  offered  by  the  Gov- 
ernment for  the  most  successful  method  of  manufacturing  indigenous  sugar.  The  beet  is  a 
biennial  plant,  native  to  the  south  of  Europe.  There  are  several  varieties  of  this  root,  each 
fitted  to  its  own  climate  and  soil ;  but  the  white  Silesian  beet  is  the  most  prized  where  it 
can  be  grown,  on  account  of  the  large  amount  of  sugar  in  the  juice,  and  the  comparative 
absence  of  salts ;  it  is  less  prone  to  decay  when  stored  previous  to  use.  The  average  com- 
position of  the  root  of  the  sugar  beet  may  be  stated  as  follows : — 

Sugar lOi  per  cent. 

Gluten 3'       " 

Woody  fibre,  &c. 5         " 

Water 81^" 

100 
The  proportion  of  sugar  varies  very  much.  First,  it  is  greater  in  some  varieties  thnn 
ofhcrs  ;  second,  it  is  greater  in  small  beets  tiian  in  large  ;  third,  in  dry  climates,  especially 
when  the  climate  is  dry  after  the  roots  have  begun  to  swell  ;  fourth,  in  light  than  heavy 
soils  ;  fifth,  in  the  part  above  than  under  ground  ;  sixth,  when  mainn-e  has  not  lieen  directly 
applied  to  the  crop.  The  average  proportion  of  sugar  extracted  Croui  beet  is  (>  per  cent., 
tiioiigh  it  is  stated  that  Y.V  per  cent,  is  obtained  in  some  well-conducted  manufactories.  In 
Fr.ince  and  B(;Igium  tlie  average  yield  is  14  or  15  tons  of  beet  to  the  acre,  while  about  Mag- 
dcl)urg  they  do  not  exceed  10  to  12  tons,  but  the  latter  are  richer  in  sugar. 

During  the  first  year  of  its  life  the  root  is  developed  to  its  full  sizr,  and  secretes  the 
whole  amount  of  sugar  which,  in  the  natural  life  of  the  i)lant,  funiislies  tiu'  material  for  the 
growtli  and  maturity  of  its  u|)per  ])art.  It  follows  tliat  when  the  plant  is  cultivated  for  its 
sugar,  it  is  ripe  for  the  sugar  manufacturers  when  its  first  year's  stage  of  development  is 
complete.  The  time  required  for  this  depends  upon  that  of  the  sowing,  and  upon  the  sea- 
son. Its  criterion  is  the  commencement  of  death  in  the  leaves.  'When  ripe  the  beet  roots 
are  dug  out,  the  mould  gently  shaken  oft",  and  the  heads  cut  off",  togetlier  with  as  much  of 


1034 


SUGAR. 


the  root  as  shows  the  presence  of  leaf  buds.  As  the  action  of  light  is  detrimental  even  to 
the  exhumed  roots,  the  latter  must  be  covered  cjuicklv.  If  the  quantity  be  small,  thej-  may 
be  covered  with  the  leaves  which  have  been  cut  off.  It  is  more  usual,  however,  to  pile  them 
in  heaps  on  the  ground,  to  hinder  the  evaporation  of  their  water,  and  to  protect  them  from 
light  and  frost  by  covering  the  heaps  with  a  tjiin  layer  of  earth.  These  mounds  are  some- 
times sprinkled  with  water,  which  is  taken  up  by  the  roots  restoring  to  them  the  plumpness 
and  crispness  which  they  have  lost  in  a  dry  season. 

BoussiNGAULT  gave  the  following  analvses  of  French  beets: — 


Where  grown. 


Time  of  taking  from  giouud,  &c. 


!Per  cent,  of 
dry  matter. 


Botanic  school  - 


Garden    of    M. 
Brogniart 

Yigneux   - 

Grenelle    - 


Eovillc,  Menrthe 

Analyzed  tiy  M. 
Braconnet. 


Au,2.  2.— Roots  small  .  -  .  . 
Sept.  1.— A  root  of  1100  grammes  =; 

about  H  lb. 

Sept.  1. — Koot,  460  grammes  =  about 

1  lb.  2i  oz. 

Sept.  7. — Koot.  TOO  to  SCO  grammes 
Touns  root  of  03  srammes  =  4'6  grains 
Sept.  26.  -Koot  from  SO  to  100  grammes 

=^  Si  oz. 
Oct.  9. — Koot,  150  grammes  =  about  5  oz. 
Sept.  28.— Root,  500  grammes  =  1  i',„  lb. 
Sept.  23.— Root.  700  grammes  =  H  lb.  - 
Aug.  7. — Root,  300  grammes  =  */,(,  lb.  - 
Aug.  11.— Root,  600  crammes  =  Ij  lb.  - 
Aug.  30.— Root,  1  kilogramme  =  2  ',^  lb. 
Beet  in   flower,  200  grammes  ;=  about 

Violb. 

Beet  of  two  years  in  seed  .  .  . 
White  beet  of  SiUsia  .  .  .  . 
Leaves  of  the  beet  -        -        -        -        . 


9-5 

7-4 

9-4 
10-0 
13-7 

161 
14-1 
16-9 
130 
15'5 
12-6 
13-1 

16-5 
5-5 

15S 
6-4 


Water.  I  Sugar. 

I 


92-6 

90-6 
90-0 
86-3 

84-9 
85-9 
831 
87-0 
84-5 
87-4 
86-9 

83-5 
945 
84-2 
93-6 


50 

4-2 

5  0 
7-3 
5-9 

100 


n-9 

8-6 
8-9 
8-2 
8-6 


00 

10-6 

1-3 


Ligneous 
fibre  and 
albumen. 


4-5 

2-5 

2-3 
1-9 
4-4 


8-2 

2-7 
6-6 
2-S 
3-1 

3-3 
2-5 
31 
3-6 


added  to  the 

lig.  matter. 

1-0 

1-6 
0-8 
3-4 


1-8 

1-7 

to  preceding 

1-6 

1-4 

3-4 
11» 
21 


The  beet-root  rasp  is  represented  in  fgs.  640,  641.      a,  a  is  the  framework  of  the  ma- 

640  641 

7» 


chine  ;  b  the  feed-plate,  made  of  cast  iron,  divided  by  a  ridge  into  two  parts ;  c,  the  hollow 
drum  ;  d,  its  shaft,  upon  either  side  of  whose  periphery  nuts  are  screwed  for  securing  the 
saw  blades  e,  e,  which  are  packed  tight  against  each  other  by  means  of  laths  of  wood ;  /  is 
a  pinion  upon  the  shaft  of  the  drum,  into  which  the  wheel  (j  works,  and  which  is  keyed  upon 
the  shaft  ^  ;  i  is  the  driving  rigger  ;  k,  pillar  of  support ;  /,  blocks  of  wood,  with  which 
the  workman  pushes  the  beet-roots  against  the  revolving  rasp  ;  ??;,  the  cliest  for  receiving 
the  beet-pap  ;  «,  the  wooden- cover  of  the  drum,  lined  with  sheet  iron.  The  drum  should 
make  50()  or  600  turns  in  the  minute. 

By  the  process  of  M.  Schutzenbach,  the  manufacture  may  be  carried  on  during  the  whole 
year,  instead  of  during  a  few  winter  months.  At  Waghiiusel,  near  Carlsruhe,  this  system 
is  adopted.  The  beets  having  been  washed,  are  rapidly  cut  up  into  small  pieces,  and  sub- 
jected to  the  drying  heat  of  a  coke  fire  for  six  hours.  They  lose  from  80  to  84  per  cent. 
of  their  weight ;  the  dried  root  may  be  kept  without  injury  for  many  months,  and  the  sugar 
is  extracted  by  infusion.  At  this  colossal  establishment,  which  in  1855  employed  3,000 
people,  and  the  buildings  of  which  covered  12  acres  of  land,  there  were  20  infusing  vessels 


*  Add  0  9  of  nitre. 


t  Add  1'5  nitre ;  the  albumen  added  to  the  sugar. 


SUGAR. 


1035 


12  to  14  feet  deep,  and  T  wide.  A  cwt.  of  raw  roots  cost  Vc?.,  and  the  dried  root  contained 
46  to  47  per  cent,  of  sugar ;  the  capital  employed  was  eighty  millions  of  francs. 

Whether  the  juice  is  extracted  from  fresh  or  dried  beets  the  subsequent  processes  are 
the  same.  The  juice,  having  been  extracted  citlier  by  infusion  or  by  submitting  the  rasped 
pulp  to  hydraulic  pressure,  is  placed  in  a  shallow  vessel,  and  mixed  with  as  much  milk  of 
lime  as  renders  it  strongly  alkaline  ;  it  is  then  boiled,  generally  by  means  of  a  copper  coil 
heated  by  high-pressure  steam.  The  excess  of  lime  is  removed  by  passing  a  stream  of  car- 
bonic acid  gas  through  the  liquid.  The  gas  is  generally  produced  by  forcing  a  stream  of  air 
through  an  enclosed  coke  fire.  The  liquid  is  next  filtered  through  cloth  concentrated  to  a 
specific  gravity  of  25'  B.,  filtered  through  animal  charcoal,  and  treated  in  all  respects  simi- 
larly to  ordinary  cane  sugar  in  a  refinery.  Though  the  vacuum-pan  is  employed  in  most 
beet-root  establishments,  there  are  some  manufacturers  who  continue  to  evaporate  in  open 
vessels. 

The  large  amount  of  water  which  has  to  be  removed  in  the  concentration  of  beet-root 
syrups  involves  the  use  of  so  much  fuel  that,  to  economize  it,  an  ingenious  apparatus  has 
been  constructed  by  M.  Call,  of  Paris.  The  principle  adopted  is  to  use  the  steam  generated 
from  the  ebullition  of  liquid  in  one  vessel  for  boiling  another,  the  steam  from  which  in  like 
manner  boils  a  third. 

Maple  Scgar. — The  manufacture  of  sugar  from  the  juice  of  a  species  of  maple-trees, 
which  grow  spontaneously  in  many  of  the  uncultivated  parts  of  North  America,  appears  to 
have  been  first  attempted  about  1752,  by  some  of  the  farmers  of  New  England,  as  a  branch 
of  rural  economy. 

The  total  production  of  maple  sugar  has  been  estinjated  at  45  millions  of  pounds,  or  the 
one  hundred  and  twenty-fifth  part  of  the  whole  quantity  of  cane  sugar  extracted  for  the  use 
of  man.  The  manufacture  of  maple  sugar  diminishes  yearly  in  proportion  as  the  native 
American  forests  are  cut  down.     See  Sugar,  vol.  ii. 


642 


1036 


SUGAR. 


Potato  Scgar. — The  manufacture  of  sugar  from  starch  derived  from  potatoes,  from 
woody  matter,  and  from  rags,  can  be  effected  by  treating  them  with  sulphuric  acid  and  heat ; 
but  the  process,  interesting  though  it  is,  is  rarely  if  ever  adopted  at  present,  as  the  sugar  is 
inferior  in  quality  to  that  obtained  from  the  cane,  and  dearer  in  price.  See  Potato  Sugar, 
vol.  ii.  a 

Animal  charcoal. — One  of  the  most  important  considerations  for  a  sugar  refiner  is  to 
furnish  himself  amply  with  bone  charcoal  of  the  best  quality,  and  to  devote  unsparing  atten- 
tion to  the  process  of  revivification.  The  theory  of  the  action  of  bone  charcoal  upon  solu- 
tions of  raw  sugar  and  other  colored  liquids  need  not  be  discussed  here.  It  may,  however, 
be  observed,  that  but  little  is  known  upon  the  subject,  and  that  the  behavior  of  bone  char- 
coal with  respect  to  metallic  oxides  and  various  salts  is  as  remarkable  as  its  action  upon 
coloring  matter. 

After  the  raw  liquor  has  been  passed  continuously  through  a  filter  of  bone  charcoal,  the 
decoloring  power  of  the  charcoal  becomes  impaired,  and  finally  lost.  This  power  may  be 
more  or  less  restored  by  the  following  means  : — 1st.  Washing  with  water.  2d.  Fermenta- 
tion. 3d.  Washing  with  weak  hydrochloric  acid.  4th.  Long  exposure  to  air  and  moisture. 
5th.  Heating  to  redness. 

The  last  plan  being  the  only  one  which  does  not  materially  injure  the  charcoal,  and 

most  completely  restore^  its  power, 
642a  C^       is    the    course    almost     invariably 

adopted  ;  it  is  however  preceded  by 
washing  with  water. 

Various  forms  of  apparatus  for 
reburning  charcoal  have  been  pro- 
posed and  adopted,  but  the  four  fol- 
lowing methods  are  the  chief  at 
present  used : — 

1st.  Burning  in  iron  pipes.  A 
furnace  about  six  feet  in  length,  and 
eighteen  inches  wide,  is  placed  be- 
tween two  rectangular  chambers 
with  which  it  communicates ;  each 
chamber  contains  thirty-two  cast- 
iron  pipes  of  four  inches  diameter 
and  nine  feet  in  length,  whose  ex- 
tremities pass  through  the  top  and 
bottom  of  each  chamber ;  to  the 
lower  end  of  each  pipe  a  sheet-iron 
cooler  is  suspended.  When  the 
charcoal  kiln  is  in  use,  the  pipes 
filled  with  charcoal  are  maintained 
at  a  dull  red  heat,  and  the  charcoal 
is  withdrawn  from  the  coolers  in 
measured  quantities  at  such  inter- 
vals of  time  as  to  allow  it  to  be  four 
hours  under  the  action  of  the  heat. 
The  advantages  of  this  plan  are 
cheapness  of  first  cost  and  sim- 
plicity; its  disadvantages  are  first, 
that  the  charcoal  is  unequally  burnt, 
the  pipes  near  the  furnace  being 
more  heated  than  those  further  re- 
moved from  it ;  second,  the  kilns 
require  frequent  repairs,  some  of 
the  pipes  being  destroyed  by  the 
fire ;  third,  the  amount  of  fuel  re- 
quired is  large ;  fourth,  the  pipes 
are  apt  to  become  choked. 

2d.  Burning  in  fire-clay  cham- 
bers. This  plan,  proposed  by  Mr. 
Parker,  of  London,  and  improved  by  Mr.  G.  F.  Chantrell,  of  Liverpool,  is  becoming 
generally  adopted.  The  plan  consists  in  arranging  narrow  chambers,  composed  of  fire- 
tiles,  and  containing  charcoal,  between  small  furnaces.  Fig.  642  shows  a  section  of  Mr. 
Chantrell's  kiln  through  one  of  the  fire-places;  fps.  642 «,  642  6,  two  front  views  of  the 
same,  c  is  the  fire-door ;  ii  the  furnace ;  the  products  of  combustion  issue  tlirough  aper- 
tures in  the  arched  roof  of  the  furnace,  and  are  compelled  to  take  a  zigzag  course  to  the  flue 
G,  by  means  of  horizontal  floors  of  tiles,  each  floor  being  open  at  alternate  ends,  b,  b  are 
apertures  for  cleaning  the  flues  or  inspecting  the  state  of  the  kiln  ;  l,  l,  the  coolers ;  m,  the 


SULPHURIC  ACID. 


1037 


measuring-box  or  receiver  ;   F,  a  heated  floor  for  drying  the  charcoal  previous  to  being  re- 
burned  ;    N,  the  firing  floor.     The  advantages  of  this  system  are,  first,  the  charcoal  is  very 
equally  burnt ;  second,  the  amount  of  fuel  required  is  small,  not  reaching  ten  per  cent,  of 
the  charcoal  reburned  ;  third,  non- 
liability to  gel  out  of  order ;  the  ^'^-^ 
chief  disadvantage  is   the  amount 
of  first  cost. 

3d.  Reburning  in  rotating  cylin- 
ders. This  plan,  like  the  former 
the  subject  of  a  patent,  is  used  at 
the  extensive  establishment  of  Mr. 
G.  Torr,  London,  the  regularity  and 
the  excellence  of  the  result  being 
considered  by  him  a  sufficient  com 
pensation  for  the  costliness  of  the 
process. 

4th.  Reburning  by  means  of 
superheated  steam.  This  ingenious 
method,  were  it  not  for  the  expense 
of  the  apparatus,  and  practical  dif- 
ficulties, would  supersede  the  pre- 
vious methods.  The  apparatus  is 
the  invention  of  MM.  Laurens  & 
Thomas  of  Paris.  A  furnace  is 
constructed,  in  the  flues  of  which  a 
number  of  cast-iron  tubes,  connect- 
ed together  and  ranged  in  order, 
are  placed ;  the  products  of  com- 
bustion, after  maintaining  the  pipes 
at  a  high  temperature,  impart  heat 
likewise  to  the  vase-shaped  vessel 
before  entering  the  chimney.  A 
jet  of  steam  being  passed  through, 
the  pipesbecomes  sufficiently  super- 
heated to  expel  the  moisture  from 
the  charcoal  contained  in  the  re- 
ceiver, and  subsequently  to  raise  it 
to  a  temperature  of  600°  F.  This 
is  sufficient  to  effect  destructive 
distillation  of  the  coloring  matter 
absorbed  by  the  charcoal.  The 
process  takes  about  eight  hours ; 
the  advantages  of  this  method  con- 
sist in  the  steam  coming  in  absolute  contact  with  every  single  grain  of  charcoal ;  the  distil- 
lates are  effectually  removed,  and  there  is  little  or  no  risk  of  the  charcoal  being  subjected 
to  too  high  a  temperature ;  but  the  plan  is  expensive  and  inconvenient,  and  has  not  been 
adopted  in  England. 

To  reburn  charcoal  the  best  methods  are  those  which  most  rapidly  remove  the  water, 
raise  the  temperature  of  each  grain  of  charcoal  to  a  uniform  temperature  of  700^  Fahr.,  and 
which  admit  of  its  being  readily  cooled  without  contact  with  the  air.  The  influences  of  time 
and  temperature,  in  the  reburning  process,  are  very  marked  ;  in  the  best  regulated  refineries 
the  decoloring  power  of  the  charcoal  is  frequently  examined  and  recorded,  and  an  analysis 
of  the  charcoal  is  made  each  month. 

SULPIIUlilC  ACID,  Vitriolic  Acid,  or  Oil  of  Vitriol.  (Acid  sulfiirique,  Fr. :  Schwe- 
felxaiire,  Germ.)  This  important  substance  now  forms  an  extensive  article  of  manufacture. 
It  appears  to  have  been  known  several  centuries  back.  It  is  found  in  large  quantities  in 
the  mineral  kingdom,  combined  with  bases,  in  some  rivers  in  the  free  state,  and  in  such 
quantity  as  to  render  the  water  acid.  It  was  previously  prepared  by  the  distillation  of 
sulphate  of  iron  or  green  vitriol,  from  which  it  received  its  name  of  oil  of  vitriol  or  vitriol- 
ic acid.  This,  process  is  even  now  carried  on  in  some  p^rts  of  Germany  to  a  certain  ex- 
tent. It  was  afterwards  found  that  it  might  be  produced  by  the  combustion  of  sulphur,  and 
the  ultimate  further  oxidation  of  the  sulphurous  acid,  thus  obtained,  liy  the  means  of  nitric 
acid  ;  and  from  time  to  time  improvements  have  been  made  in  the  process,  until  it  is  now 
almost,  perhaps  entirely,  perfect,  tmd  is  the  process  most  generally  adopted.  We  shall 
proceed  to  describe  the  process  more  fully,  as  it  is  now  carried  on. 

In  the  first  place  the  sulphur  is  burnt  on  suitable  hearths,  and  the  sulphurous  acid  pro- 
duced is  carried  by  flues,  together  with  some  nitrous  and  nitric  acids,  generated  in  the  same 
f  r.-nace  from  a  mixture  of  nitre  and  sulphuric  acid,  into  the  large  leaden  chambers,  into 


1038 


SULPHURIC  ACID. 


which  steam  and  air  are  also  admitted  ;  hero  the  different  gases  react  on  each  other,  and  the 
sulpluirous  acid  becomes  converted  into  sulphuric  acid,  and  falls  into  the  dilute  sulphuric 
acid  which  is  placed  in  the  bottom  of  the  chamber,  which  thereby  becomes  stronger,  and, 
when  of  sufficient  strength,  is  drawn  off,  and  concentrated  first  in  leaden  vessels,  and  finally 
in  vessels  of  platinum.     The  apparatus  nec^sary  for  the  manufacture  of  sulphuric  acid  is 

1.  Hearth  on  which  the  sulphur  is  burnt.  2.  Iron  pot  tor  the  nitre.  3.  Leaden  cham- 
bers.    4.  Steam  boiler.     5.   Concentrating  pans,  (leaden.)     0.   Platinum  or  glass  retorts. 

The  place  where  the  sulphur  is  burnt  is  a  kind  of  furnace,  but  instead  of  the  grate  there 
is  a  stone  hearth  or  iron  plate,  called  the  sole.  The  nitre  pot  or  pan  is  of  cast  iron.  In  it 
the  nitre  is  decomposed  by  the  sulphuric  acid,  and  it  is  placed  in  the  burner  when  required. 
The  leaden  chamber  has  the  form  of  a  parallelopiped,  the  size  varying  with  the  amount  of 
work  reiiuircd  to  be  done  To  produce  10  tons  of  oil  of  vitriol  weekly,  the  chamber  should 
liave  a  capacity  of  35,000  cubic  feet ;  or  a  length  of  187  feet,  a  breadth  of  12A  feet,  and  a 
height  of  15  feet.  {Plmrmaceutical  limes,  Jan.  2,  1847.)  The  bottom  is  covered  to  the 
depth  of  3  or  4  inches  with  water  acidulated  with  sulphuric  acid.  These  leaden  chambers 
are  sometimes  divided  into  3  or  4  compartments  by  leaden  curtains  placed  in  them,  which 
cause  the  more  perfect  mixture  of  the  gases.  Fi^.  C43  is  a  drawing  of  one  thus  divided, 
taken  from  Fereira's  Materia  Medico. 

013 


JliS 


Oil  or  Vithioi,  Cii.vmi  i:  :. 
a.  Steam  boiler.     Ii,  Pection  of  furnace  or  hurner.    r/.inil/.  1.' aden  cmtains  inun  Uie  roof  of  the 
chamber  to  within  six  inches  of  the  floor,    e.  Leaden  cm  tain  li-inir  Iroin  tlic  floor  to  within  si.x  inciies  of 
the  roof,     f/,  Le.iden  conduit  or  vent-tube  for  the  di^charfre  of  uncondensable  irases.     It  .should  commu- 
nicate with  a  tall  chimney  to  carry  off  these  gases,  and  to  occasion  a  slight  draught  through  the  chamber. 

These  curtains  serve  to  detain  the  vapors,  and  cause  them  to  advance  in  a  gradual 
manner  through  the  chamber,  so  that  generally  the  whole  of  the  suljihurous  acid  is  convert- 
ed into  sulplmric  acid  and  deposited  in  the  water  at  the  bottom  before  it  reaches  the  dis- 
charge pipes ;  but  as  such  is  not  always  the  case,  there  are  sometimes  smaller  chambers, 
also  containing  water,  appended  to  the  larger,  from  which  they  receive  the  escajiing  gases 
before  they  are  allowed  to  pass  out  in  the  air,  and  thus  prevent  loss.  These  smaller  cham- 
bers are  seen  in  Jiff.  C44  c,  d,  also  taken  from  Pereira's  Materia  Mcdica. 

r-i4 


,,,f!ifff'ni'niiieiiiBiiii*!?jii!iii»ira 


Oil  of  Vitkiol  .Masufactoky. 
a,  Sulphnrbnrnp.rorfurnace.  b.  First  leaden  chamber,  e,  <L  Second  and  third  smaller  leaden  chambers. 
c.  Slea"!  boiler.  /  Fhie  pipe  or  chimney  of  the  furnace,  g,  Steam  pipe.  h.  The  flue  or  i)ipc  conveyinK 
the  residual  gas  from  the  first  to  the  second  leaden  rhamber.  i.  Pipe  conveying  the  gas,  not  absorbid 
in  tile  first  and  second  chamber,  into  the  third.  /-,  Flue  or  waste  pipe.  /,  Manhole,  by  which  the  work- 
nn'n  enter  the  rhamber  when  tlic  process  is  not  ^oinc  on.,  m.  Pipe  for  withdrawing  a  small  portion  of 
sulpliiiric  a'-id  from  the  ch.imber,  in  order  to  obtain  it.s  sp  gr.  by  the  hydrometer. 


SULPllUlilO  ACID.  103'J 

Anotlicr  method  for  preventing  this  loss  has  been  contrived  by  M.  Gay-Lussac,  and 
made  the  subject  of  a  patent  in  this  country  by  his  agent,  M.  Sautter.  It  consists  in  causing 
the  waste  gas  of  the  vitriol  chamber  to  ascend  tlirough  the  chrndval  cascade  of  M.  Clement 
Desormes,  and  to  encounter  there  a  stream  of  sulphuric  acid  of  specific  gravity  1"750.  The 
nitrous  aciil  gas,  wliich  is  in  a  well  regulated  cliauiber  always  slightly  redundant,  is  perfect- 
ly absorbed  by  the  said  sulphuric  aiid  ;  which,  thus  impregnated,  is  made  to  trickle  down 
through  another  cascade,  up  through  which  passes  a  current  of  sulphurous  acid,  from  tlie 
combustion  of  sulphur,  in  a  little  adjoining  chamber.  The  condensed  nitrous  acid  gas  is  thercv 
by  immediately  translbrmed  into  nitrous  gas,  (deutoxide  of  azote,)  wlach  is  transmitted  from 
this  second  cascade  into  the  large  vitriol  chamber,  and  there  exercises  its  well  known  re- 
action upon  its  aeriform  contents.  Tiie  economy  thus  clfectcd  in  the  sulphuric  acid  manu- 
facture is  such  that  for  100  parts  of  sulphur  3  of  nitrate  of  soda  will  suffice,  instead  of  9  or 
10  as  usually  consumed. 

The  tiue  or  waste  pipe  serves  to  carry  off  the  residual  gas,  which  should  contain  nothing 
but  the  nitrogen  of  the  atmosphere,  which  has  been  introduced. 

Having  now  detailed,  with  sufficient  minuteness,  the  construction  of  the  chamber,  we 
shall  next  describe  the  mode  of  operating  with  it.  There  are  at  least  two  plans  at  present 
in  use  for  burning  the  sulphur  continuously  in  the  oven.  In  the  one,  the  sulphur  is  laid  on 
the  hearth,  (or  rather  on  the  flat  hearth  in  the  separate  oven,  above  described,)  and  is  kin- 
dled by  a  slight  fire  placed  under  it ;  which  fire,  however,  is  allowed  to  go  out  after  the  first 
day,  because  the  oven  becomes  by  that  time  sufficiently  heated  by  the  sulphur  flames  to  carry 
on  the  subsequent  combustion.  Upon  the  hearth  an  iron  tripod  is  set,  supporting,  a  few 
inches  above  it,  a  hemispherical  cast-iron  bowl  (Ijasin)  charged  with  nitre  and  its  decompos- 
ing proportion  of  strong  sul[)huric  acid.  In  tlic  other  plan,  12  parts  of  bruised  sulphur,  and 
1  of  nitre,  are  mixed  in  a  leaden  trough  on  the  floor  with  1  of  strong  sulphui-ic  acid,  and 
the  mixture  is  shovelled  through  the  sliding  iron  door  upon  the  hot  hearth.  The  succes- 
sive charges  of  sulfjhur  are  proportioned,  of  course,  to  the  size  of  the  chamber.  In  one  of 
the  largest,  which  is  120  feet  long,  20  broad,  and  16  high,  12  cwt.  are  burned  in  the  course 
of  24  hours,  divided  into  6  charges,  every  fourth  hour,  of  2  cwt.  each.  In  chambers  of 
one-sixth  greater  capacity,  containing  1,400  metres  cube,  1  ton  of  sulphur  is  burned  in  24 
hours.  Tills  immense  production  was  first  introduced  at  Chaunay  and  Dieuze,  under  the 
management  of  M.  Clement-Desormes.  The  bottom  of  the  chamber  should  be  covered  at 
first  with  a  tliin  stratum  of  sulphuric  acid,  of  sp.  gr.  1  "07,  which  decomposes  hyponitric  acid 
into  oxygen  and  binoxide  of  nitrogen  ;  but  not  with  mere  water,  which  would  absorb  the 
hyponitric  acid  vapors,  and  withdraw  them  from  their  sphere  of  action.  The  crystalline 
compound,  described  below,  is  often  formed,  and  is  deposited  at  low  temperatures,  in  a 
crust  of  considerable  thickness  (from  one-half  to  one  inch)  on  the  sides  of  the  chamber,  so 
as  to  render  the  process  inoperative.  A  circumstance  of  this  kind  occurred,  in  a  very  strik- 
ing manner,  during  winter,  in  a  manufacture  of  oil  of  vitriol  in  Russia  ;  and  it  has  sometimes 
occurred,  to  a  moderate  extent,  in  Scotland.  It  is  called,  at  Marseilles,  the  maladic  dcs 
chanibres.  It  may  be  certainly  prevented,  ))y  maintaining  the  interior  of  the  chamljer,  by 
a  jet  of  steam,  at  a  temperature  of  100^  Fahr.  When  these  crystals  fall  into  the  diluted 
acid  at  the  bottom,  they  are  decomposed  with  a  violent  effervescence,  and  a  hissing  gur- 
gling noise,  somewhat  like  that  of  a  tun  of  beer  in  brisk  fermentation. 

M.  Clement-Desormes  demonstrated  the  proposition  relative  to  the  influence  of  tempera- 
ture by  a  decisive  experiment.  lie  took  a  glass  globe,  furnished  with  three  tubulures,  and 
put  a  bit  of  ice  into  it.  Through  the  first  opening  he  then  introduced  sulphurous  acid  gas; 
through  the  second,  oxygen  ;  and  through  the  third  l)inoxide  of  nitrogen.  While  the  globe 
was  kept  cool  I)y  being  plunged  in  iced  water,  no  sulphuric  acid  was  formed,  though  all  (he 
ingredients  essential  to  its  production  were  present.  Hut  on  ex])osing  the  gloI)e  to  a  tem- 
perature of  100°  Fahr.,  the  four  bodies  began  immediately  to  react  on  each  other,  and  oil 
of  vitriol  was  condensed  in  visible  strife. 

The  introduction  of  steam  is  a  modern  invention,  which  has  vastly  facilitated  and  in- 
creased the  production  of  oil  of  vitriol.  It  serves,  by  powerful  agitation,  not  only  to  mix 
the  dilfercnt  gaseous  molecules  intimately  together,  but  to  impel  them  against  each  other, 
and  thus  bring  them  within  the  sphere  of  their  mutual  chemical  attraetifm.  This  is  its 
mcclianical  ellect.  Its  chemical  agency  is  still  more  important.  Uy  supplying  moisture  at 
every  point  of  the  immense  included  space,  it  determines  the  formation  of  liydious  sulphu- 
ric aciil,  from  the  compound  of  nitiic,  hypo-nitric,  sulphurous,  and  dry  sulphuric  acids. 

Besides  the  process  here  described,  which  is  called  the  coiif ! ii iiotis  prncesx^  tUcro  was 
.another  formerly  adopted,  called  the  hitennitlcnt  j»-i>rrss.  This  was  al.so  carried  on  in 
largo  leaden  chambers ;  but  instead  of  a  contintious  stream  of  air,  as  passes  into  the  chambers, 
thi'ough  the  furnace  by  the  continuous  [jrocess,  the  chaml)crs  were  opened  now  and  then  to 
introduce  frcsli  atmospheric  air.  This  ]irocess  is,  however,  now  generally  abandoned,  on 
account  of  tlie  difficulties  and  (hdays  attending  it,  though  it  afforded  large  pi'oducts  in  skil- 
ful hands.  The  following  is  just  an  outline  of  tlic  process  : — On  the  intermittent  plan,  after 
the  consumption  of  each  charge,  and  contjcn.sation  of  the  product,  the  chamber  was  opened 


1040 


SULPHURIC  ACID. 


and  freely  ventilated,  so  as  to  expel  the  residuary  nitrogen,  and  replenish  it  with  fresh 
atmospheric  air.  In  this  system  there  were  four  distinct  stages  or  periods  : — 1.  Combustion 
for  two  hours ;  2.  Admission  of  steam,  and  settling  for  an  hour  and  a  half ;  3.  Conversion 
for  three  hours,  during  which  interval  the  drops  of  strong  acid  were  heard  falling  like  heavy 
hailstones  on  the  bottom ;  4.  Purging  of  the  chamljcr  lor  three-quarters  of  an  hour. 

The  complicated  changes  which  take  place  in  the  leaden  chambers  during  the  conversion 
of  the  sulphurous  acid  into  sulphuric  acid,  were  first  traced  by  M.  Clement-Desormes.  lie 
showed  that  hyponitrie  acid  and  sulphurous  acid  gases,  when  mixed,  react  on  each  other 
through  the  intervention  of  moisture  ;  that  there  thence  resulted  a  crystalline  combination 
of  sulphuric  acid,  binoxide  of  nitrogen,  and  water ;  that  this  crystalline  compound  was 
instantly  destroyed  by  more  water,  with  the  separation  of  the  sulphuric  acid  in  a  liquid 
state,  and  the  disengagement  of  binoxide  of  nitrogen  ;  that  this  gas  re-constituted  hyponitiic 
acid  at  the  expense  of  the  atmospheric  oxygen  of  the  leaden  chamber,  and  thus  brought 
matters  to  their  primary  condition.  From  this  point,  starting  again,  the  particles  of  sul- 
phur in  the  sulphurous  acid,  through  the  agency  of  water,  became  fully  oxygenated  by  the 
hyponitrie  acid,  and  fell  down  in  heavy  drops  of  sulphuric  acid,  while  the  binoxide  of  nitro- 
gen derived  from  the  hyponitrie  acid,  had  again  recourse  to  the  air  for  its  lost  dose  of  oxy- 
gen. This  beautiful  interchange  of  the  oxygenous  principle  was  found  to  go  on,  in  their 
experiments,  till  either  the  sulphurous  acid  or  oxygen  in  the  air  was  exhausted. 

They  verified  this  proposition, with  regard  to  what  occurs  in  sulphuric  acid  chambers,  by 
mixing  in  a  crystal  globe  the  three  substances,  binoxide  of  nitrogen,  sulphurous  acid,  and 
atmospheric  air.  The  immediate  production  of  red  vapors  indicated  the  transformation  of 
the  binoxide  into  hyponitrie  acid  gas ;  and  now  the  introduction  of  a  very  little  water  caused 
the  proper  reaction,  for  opaque  vapors  arose,  which  deposited  white  star-form  crystals  on 
the  surface  of  the  glass.  The  gases  were  once  more  transparent  and  colorless ;  but  another 
addition  of  water  melted  these  crystals  with  efiervcscence,  when  ruddy  vapors  appeared. 
In  this  manner  the  phenomena  were  made  to  alternate,  till  the  oxygen  of  the  included  air 
was  expended,  or  all  the  sulphurous  acid  was  converted  into  sulphuric.  The  residuary 
gases  were  found  to  be  hyponitrie  acid  gas,  and  nitrogen  without  sulphurous  acid  gas  ;  while 
unctuous  sulphuric  acid  bedewed  the  hiner  surface  of  the  globe.  Hence,  they  justly  con- 
cluded their  new  theory  of  the  manufacture  of  oil  of  vitriol  to  be  demonstrated. 

By  a  modification  of  this  last  process,  the  manufacture  of  sulphuric  acid  from  sulphur 
and  nitre  may  be  elegantly  illustrated.  Take  a  glass  globe  with  an  orifice  at  its  top  laige 
enough  to  take  a  lead  stojiper,  through  which  are  fixed  five  glass  tubes ;  one  in  connection 
with  a  flask  generating  sulphurous  acid  from  copper  turnings  and  sulphuric  acid  ;  the  second 
in  connection  with  a  gasometer  supplying  binoxide  of  nitrogen  ;  the  third  in  connection 
with  a  vessel  capable  of  supplying  a  tolerable  current  of  steam ;  the  fourth  connected  to 
another  gasometer  supplying  atmospheric  air ;  and  the  fifth,  which  is  left  open,  does  not  pro- 
ject far  into  the  globe,  and  serves  to  carry  off  the  residual  nitrogen.  By  regulating  the 
influx  of  the  different  gases  and  steam,  the  solid  white  crystalline  compound  may  be  alter- 
nately formed  and  again  decomposed.  The  bottom  of  the  glass  globe  is  formed  like  a 
funnel,  and  the  sulphuric  acid,  when  formed,  thus  runs  down  the  sides  into  a  bottle  placed 
beneath.  Some  difference  of  opinion  exists  about  the  composition  of  the  crystalline  com- 
pound thus  formed  sometimes  in  leaden  chambers.  It  is  probably  a  compound  of  sulphuric 
acid  and  binoxide  of  nitrogen  N0"+2S0',  but  it  is  not  decided  if  it  contains  water  or  not. 

Peligot  (Ann.  Chim.  et  Phys.  3me  ser.  xii.  1844)  states  that  the  sulphurous  acid  is  oxi- 
dized ince-fsantli/  and  cxclus'n-ebj  by  nitric  acid  only,  and  he  accounts  for  it  in  this  way : — The 
hj-ponitric  acid  (XO'')  by  contact  with  water  is  converted  into  nitric  acid,  and  nitrous  acid 
(2\0'  +  nO  =  HNO''-i-N(V),  and  the  nitrous  acid  (XO^)  is  again  decomposed  by  more  water 
into  nitric  acid  and  binoxide  of  nitrogen  3XO'+HO  =  HXO^+2XO^  The  binoxide  of 
nitrogen  by  contact  with  atmospheric  air  is  again  converted  into  hyponitrie  acid  (XC-^- 
0^  =  X0^),  which  goes  through  the  same  changes  as  before. 

There  are  some  points  in  the  manufacture  of  sulphuric  acid  which  require  attention. 

1  St.  If  the  heat  in  the  sulphur  furnace  is  too  high,  or  when  there  is  not  a  sufficient  supply 
of  air,  some  sulphur  sublimes,  and  is  condensed  in  the  chamber,  and  at  last  falls  into  the 
sulphuric  acid  at  the  bottom  of  the  chamber.  By  this  means,  not  only  is  less  sulphuric 
acid  produced,  but  the  sulphuric  acid,  when  drawn  from  the  chamber,  contains  some  sul- 
phur in  suspension :  in  this  case  it  must  be  allowed  to  stand,  so  as  to  deposit  the  sulphxu", 
which  may  be  collected,  washed,  dried,  and  again  used.  If  the  sulphur  were  not  removed 
before  concentrating,  it  would,  at  the  temperature  requisite  for  evaporation,  decompose  the 
sulphuric  acid,  with  the  escape  of  sulphurous  acid  gas,  and  hence  much  sulphuric  acid  would 
^'e  lost.  The  reaction  that  would  take  place  is  represented  by  the  following  equation : — 
2IIS0^  -f  S  =  3S0'  +  2H0 

Sulphuric  acid.  Sulphur.  Sulphurous  acid  gas.  TVater. 

2d.  If  there  is  not  a  sufficient  quantity  of  steam  admitted  into  the  chamber,  the  solid 
compound  of  sulphuric  acid  and  binoxide  of  nitrogen,  above  mentioned,  would  be  formed 


SULPHUKIO  ACID.  lOil 

on  the  sides  of  the  chamber,  and  thus  remove  the  oxidizing  agent  from  action,  and  hence 
a  large  quantity  of  sulphurous  acid  would  escape  by  the  waste-pipe  unchanged. 

3d.  A  deficiency  of  nitric  acid  in  the  chamber  also  causes  great  loss ;  the  Bulphurous 
acid,  as  in  the  former  case,  escaping  unoxidized. 

The  first  of  these  three  subjects  was  counteracted  by  M.  Grovelle,  who,  taking  advan- 
tage of  an  idea  put  forth  by  M.  Clement  Desormes,  constructed  a  furnace  for  burning  the 
sulphur,  so  as  to  have  a  double  current  of  air.  lie  substituted  for  the  sole  of  the  furnace 
some  parallel  bars  of  iron,  on  which  were  placed  cast-iron  pans  or  boxes,  bound  together, 
but  leaving  intervals  for  the  entrance  of  air  between  each  :  these  were  filled  with  sulphur, 
which  was  then  ignited,  and  thus  a  plentiful  supply  of  air  was  constantly  kept  up. 

Faming,  or  Nordhausen  sulphuric  acid.     At  Nordhausen  and  other  parts  of  Saxony, 
sulphuric  acid  continues  to  be  made  upon  the  old  plan. 
This  consists  in  first  subjecting  sulphate  of  iron  or  green  645 

vitriol  to  a  gentle  heat,  by  which  it  is  deprived  of  its 
water  of  crystallization ;  it  is  then  distilled  in  earthen- 
ware, tubular,  or  pear-shaped  retorts,  of  which  a  large 
number  are  placed  in  a  gallery  furnace.  Fig.  645,  the 
fire-place  ;  abb,  chamber  on  each  side  of  the  fire-place, 
for  depriving  the  green  vitriol  (c  c)  of  its  water. 

To  these  retorts  ai-e  adapted  earthenware  receivers, 
into  which  some  ordinary  sulphuric  acid  is  previously 
placed,  to  condense  all  the  anhydrous  sulphuric  acid 
which  comes  over.  The  heat  is  raised  gradually,  and  at 
last  the  retorts  are  subjected  to  an  intense  heat,  which 
is  kept  up  for  several  hours. 

Some  sulphurous  acid  gas  escapes,  arising  from  the  decomposition  of  some  of  the  sul- 
phuric^acid  of  the  sulphate  by  the  oxide  of  iron,  and  nothing  remains  in  the  retorts  but 
sesquioxide  of  iron. 

3FcS0^  =  Fe'O'  -}-  280^  +  SO' 

Green  vitriol.  Oxide  of  iron.        Anliydrous  sulphuric  acid.        Sulphurous  acid 

Anhydrous  sulphuric  acid.  This  is  most  easily  obtained  by  subjecting  the  Nordhausen 
sulphuric  acid  to  a  gentle  heat  in  a  glass  retort,  to  which  is  adapted  a  dry  receiver  placed 
in  ice.  White  fumes  of  anhydrous  sulphuric  acid  come  over  and  are  condensed  in  the  re- 
ceiver. Care  must  be  taken  to  avoid  water  coming  into  contact  with  it,  as  it  unites  with  it 
with  some  violence. 

HSO*SO»  =  HSOn  +  SO' 

Nordhausen  sulphuric  acid.  Common  sulphuric  acid.  Anhydrous  sulphuric  acid. 

It  is  best  to  have  a  receiver,  which  can  be  hermetically  sealed  as  soon  as  the  operation 
is  completed. 

Properties  of  the  different  Sulphuric  Acids. 

Anhi/drous  sulphuric  acid.  SO'.  This  is  a  white  crystalline  body,  very  much  resem- 
bling asbestos  in  appearance.  Exposed  to  the  air,  some  of  it  absorbs  moisture,  and  the 
rest  flies  oif  in  white  fumes.  Dropped  into  water  it  produces  a  hissing  noise,  just  like  red- 
hot  iron,  and  in  large  quantities  causes  explosion.  It  melts  at  66°  Fahr.,  and  boils  at 
about  120"  Fahr.  The  sp.  gr.  of  the  li(iuid,  at  78^  Fahr.,  is  1-97,  (Pcrcira,)  and  that  of  its 
vapor  3'0,  (Mitschcrlich.)     It  does  not  present  acid  properties  unless  moisture  be  present. 

Nordhausen  sulphuric  acid.  IISO',  SO'.  This  is  an  oily  liqiiid,  generally  of  a  brown 
color,  (from  some  organic  matter,)  which  gives  off  white  fumes  of  anhydrous  sulphuric  acid 
when  exposed  to  the  air.  Its  sp.  gr.  is  about  1-9.  It  is  imported  in  stoneware  bottles, 
having  a  stoneware  screw  for  a  stopper.  It  is  probably  only  a  solution  of  anhydrous  sul- 
phuric acid  in  ordinary  oil  of  vitriol,  as,  after  being  subjected  to  a  gentle  heat,  nothing  re- 
mains but  the  latter.  It  often  contains  several  impurities.  It  is  principally  used  for  dissolv- 
ing indigo,  which  it  does  completely  without  destroying  the  color. 

Ordinary  sulphuric  acid  or  oil  of  vitriol.  II80''.  Sp.  gr.  1'845.  This  is,  when  pure, 
a  colorless,  transparent,  highly  acrid,  and  most  powerful  corrosive  liquid.  It  is  a  very 
strong  mineral  acid,  one  drop  being  sufficient  to  communicate  the  power  of  reddening  litmus 
paper  to  a  gallon  of  water,  and  produces  an  ulcer  if  placed  upon  the  skin.  It  chars  most  or- 
-  ganic  substances.  This  depends  upon  its  attraction  for  water,  which  is  so  great  that,  when  ex- 
posed in  an  open  saucer,  it  imbibes  one-third  of  its  weight  from  the  atmosphere  in  twenty- 
four  hours,  and  fully  six  times  its  weight  in  a  few  months.  Hence  it  should  be  kept  excluded 
from  the  air.  If  four  parts,  hy  weight,  of  the  strongest  acid  be  suddenly  mixed  with  one  part 
of  water,  both  being  at  50'  Fahr.,  the  temperature  will  rise  to  300''  Fahr. ;  while,  on  the  other 
hand,  if  four  j)arts  of  ice  be  mixed  with  one  of  sulphuric  acid,  they  immediately  li(}uefy  and 
;i'i1c  the  thermometer  to  4°  below  zero.  In  this  last  case  the  heat,  that  would  otherwise 
Vol.  III.— 66 


1042  TANGLE. 

have  been  given  off,  has  been  employed  in  liquefying  the  ice.  Upon  mixing  the  acid 
and  water  they  both  suffer  condensation,  tlie  dilute  acid,  thus  formed,  occupying  less  space 
than  the  two  separately,  and  hence  the  evolution  of  heat.  This  affinity  for  water,  which 
sulphuric  acid  possesses,  is  often  made  use  of  for  evaporating  liquids  at  a  low  temperature. 
The  liquid  is  placed  in  a  dish  over  another  dish  containing  sulphuric  acid,  and  both  are  plac- 
ed under  the  receiver  of  an  air  pump.  Such  is  the  rapidity  with  which  the  evaporation  is 
carried  on,  that  if  a  small  vessel  of  water  be  so  placed  it  will  speedily  be  frozen.  Sulphuric 
is  decomposed  by  several  substances  when  boiled  with  them ;  such  are  most  organic  sub- 
stances, sulphur,  phosphorus,  and  .several  of  the  metals,  as  mercury,  copper,  tin,  &c. 

Sulphui  ic  acid  of  s|).  gr.  r845,  boils  at  about  620°  Fahr.,  and  may  be  distilled  unchanged. 
This  is  the  best  way  to  oi)tain  it  pure.  It  is  a  most  powerful  poison.  If  swallowed  in  its 
concentrated  state,  even  a  small  (juantity,  it  acts  so  powerfully  on  the  throat  and  .'<tomach 
as  to  cause  intolerable  agony  and  speedy  death.  Watery  diluents  mixed  with  chalk  or 
magnesia  are  the  readiest  antidotes. 

Ordinary  oil  of  vitriol  generally  contains  some  sulphate  of  lead,  which  will  be  precipi- 
tated, as  a  white  powder  by  dilution  with  water ;  since  so  much  of  it  is  made  from  iron  pyrites 
at  the  present  day,  it  contains  arsenic  in  variable  quantities.  The  best  test  for  sulphuric  acid, 
eitlier  free  or  combined,  as  soluble  salts,  is  a  salt  of  barium.  An  extremely  small  quantity 
of  sulphuric  acid,  or  a  soluble  salt  of  it,  is  thus  easily  detected  by  the  grayish-white  cloud  of 
sul[)hates  of  baryta  which  it  occasions  in  the  solution.  100  parts  of  the  concentrated  acid 
are  neutralized  by  143  parts  of  dry  pure  carbonate  of  potash,  and  by  110  of  dry  pure  car- 
bonate of  soda. 

The  presence  of  saline  impurities  in  sulphuric  acid  may  be  determined  by  evaporating  a 
certain  quantity  to  dryness  in  a  platinum  capsule.  If  more  than  2  grains  of  residue  remain 
out  of  500  of  acid,  it  may  be  considered  impure. 

Of  all  the  acids,  the  sulphuric  is  most  extensively  used  in  the  arts,  and  is,  in  fact,  the 
primary  agent  for  obtaining  almost  all  the  others,  by  disengaging  them  from  their, saline 
combinations.  In  this  way  nitric,  hydrochloric,  tartaric,  acetic,  and  many  other  acids,  are 
procured.  It  is  employed  in  the  direct  formation  of  alum,  of  the  sulphates  of  copper,  zinc, 
potassa,  soda ;  in  that  of  sulphuric  etlier,  of  sugar  by  the  saccharification  of  starch,  and  in 
the  preparation  of  phosphorus,  &c.  It  serves  also  for  opening  the  pores  of  skins  in  tanning, 
for  clearing  the  surfaces  of  metals,  for  determining  the  nature  of  several  salts  by  the  acid 
characters  that  arc  disengaged,  &c. 

According  to  Graham  there  are  three  hydrates  of  sulphuric  acid  besides  the  Nordhausen 
acids,  viz. : — 

Monohydratf  of  Rnlphuric  acid,  oil  of  vitriol,  of  sp.  gr.  1"845.  IISO''.  This  acid  is  a 
dense  oily,  colorless  lifiuid.  Boils  at  620"  Fahr.,  and  freezing  at — 29"  Fahr.,  yielding  some- 
times regular  six-sided  prisms  of  a  tabular  form. 

BinJtydratc  of  sulphuric  acid,  sometimes  called  Eisol,  (ice  oil,)  sp.  gr.  1'78.     HSO''  +  IIO. 

In  cold  weather  acid  of  this  density  readily  freezes,  and  produces  large,  hard  crystals, 
somewhat  resembling  4;rystals  of  carbonate  of  soda.  The  melting  point  of  these  crystals  is 
45"  Fahr.  If  the  density  be  either  augmented  or  lessened  the  freezing  point  is  lowered. 
The  crystals  have  a  sp.  gr.  of  1  '924. 

Tcrhydratc  of  sulphuric  acid.  Acid  of  sp.  gr.  1-632.  nS0^-f2II0.  This  acid  is  ob- 
tained by  evaporating  a  dilute  acid  iyi  vacuo  at  212°  Fahr.  It  is  in  the  proportions  contain- 
ed in  this  hydrate  that  sulphuric  acid  and  water  undergo  the  greatest  condensation  when 
mixed. 

T 

TANGLE.     Laminaria  diqitata  of  Lamoroux.     See  Alg^. 

TANXIN,  or  TANNIC  ACID.  (  Tarmin,  Fr. ;  Gcrtstoff,  Germ.)  Fnder  the  name  fan- 
vin  were  formerly  tmderstood  all  those  astringent  principles  which  were  capable  of  combining 
with  the  skins  of  animals  to  form  leather,  of  precipitating  gelatine,  of  forming  bluish  black 
precipitates  with  the  persalts  of  iron,  and  of  yielding  nearly  insoluble  compounds  with  some 
of  tlie  organic  alkalies.  But  it  has  of  late  years  been  proved  that  there  are  several  different 
kinds  of  tannic  acid,  most  of  which  possess  an  acid  reaction. 

These  principles  are  widely  diffused  in  the  vegetable  kingilom  ;  most  of  our  forest  trees, 
a.s  the  oak,  elm,  pines,  firs,  &c. ;  pear  and  plum  trees  contain  it  in  varialile  <|uantities. 

It  is  also  found  in  .some  fruits.  Many  shrul)S,  as  the  su'uach  and  whortleberry,  also  con- 
tain it  in  large  quantities,  and  on  that  account  are  largely  used  in  dyeing  and  tanning.  The 
roots  of  the  tormentilla  and  bistort  are  also  powerfully  astringent  from  containing  it. 
Coff"ee  and  tea  also  contain  a  modification  of  this  principle.  The  astringent  principle  in  all 
the  above  mentioned  (except  coffee)  precipitates  the  persalts  of  iron  bluish  l)lack,  or  if  a  free 
acid  be  present  the  solution  becomes  dark  green.  The  astringent  principle  of  many  vegeta- 
bles precipitates  the  persalts  of  iron  of  a  dark  green, — such  are  catechu,  kino,  &c.  Some 
few  plants  contain  another  modification  of  this  astringent  principle,  which  precipitates  the 
persalts  of  iron  of  a  gray  color, — such  are  rhatany,  the  common  nettle,  &c. 


TAXXING.  1043 

Many  of  these  tannic  acids  have  received  names  which  refer  to  the  plants  from  which 
they  are  obtained.  The  most  important  and  best  known  of  all  these  is  the  f/allo-taiinic  acid, 
or  that  which  is  extracted  from  gall-nuts.  There ai-e also  guerci-tannic  acid,  from  the  oak; 
mori-tannic  acid,  or  that  from  the  fustic,  {morns  timtoria,)  &c. 

The  only  one  which  need  be  described  here  is  the  gallo-taimic  acid ;  it  is,  in  fact,  the 
only  one  which  is  perfectly  known.  It  is  usually  obtained  from  the  gall-nuts,  which  are 
excrescences  formed  on  the  leaves  of  a  species  of  oak  (tjuercH.s  inf'ectoria)  by  the  puncture 
of  a  small  insect,  by  the  process  first  proposed  l>y  M.  Pclouze,  which  consists  in  exhausting 
the  powdered  gall-nuts  by  allowing  ordinary  ether  to  percolate  through  them  in  a  proper 
apparatus.  The  ether,  which  always  contains  some  water,  separates  at  tlie  bottom  of  the  ap- 
paratus into  two  distinct  layers;  the  under  one,  being  the  water,  containing  all  the  tannic 
acid,  and  the  upper  one,  the  ether,  containing  the  gallic  acid  and  coloiing  matter.  The 
solution  of  tannic  acid  is  washed  with  ether  and  evaporated  gently  to  dryness,  when  the 
gallo-tannic  acid  is  left  as  a  pale  buff-colored  amorphous  residue. 

Some  gall-nuts  contain  a^  much  as  67  per  cent,  of  gallo-tannic  acid,  and  about  2  per 
cent,  of  gallic  acid,  (Guibourt.)  Gallo-tannic  acid  is  freely  soluble  in  water,  soluble  in  di- 
luted alcohol,  slightly  in  ether.  The  tannic  acids  are  all  remarkable  for  the  avidity  with 
which  they  absorb  oxygen;  the  gallo-tannic  acid  becoming  gallic  acid. 

A  saturated  aqueous  solution  of  gallo-tannic  acid  is  precipitated  by  sulphuric,  hydrochlo- 
ric, phosphoric,  and  some  other  acids.  When  boiled  for  some  time  with  diluted  sulphuric 
or  hydrochloric  acid  it  is  converted  into  sugar  and  gallic  acid,  (Strecker;)  the  latter  crystal- 
lizes on  cooling,  whilst  the  glucose  remains  in  solution. 

C%"0=^         +         lOHO     =     3(3HO   C"H'0')     +     C'-n'=0"2aq. 

GalIo-t.innic  acid.  Gallic  acid.  Glucose. 

The  composition  of  the  gallo-tannates  is  but  imperfectly  knowa,  and  it  is  not  decided  if 
the  acid  be  dibasic  or  tribasic.  A  solution  of  gallo-tannic  acid  gives,  with  persalts  of  iron,  a 
bluish  black  precipitate,  which  is  the  basis  of  ordinary  black  writing  ink.  The  most  remark- 
able compound  of  gallo-tannic  acid  is  that  which  it  forms  with  gelatine,  which  is  the  basis 
of  leather.     See  Tanxixg. 

By  the  reaction  of  heat  gallo-tannic  acid  is  converted  into  pyrogaltic  acid,  and  this  dis- 
tinguishes it  from  the  other  species  of  tannic  acid,  as  they  do  not  yield  pyrogallic  acid  when 
subjected  to  the  same  treatment. 

The  following  formula  will  show  the  relation  existing  between  gallo-tannic  acid,  gallic 
acid,  and  pyrogallic  acid. 

C'^H--0*^       +      lOHO  =  3(3HO'  C'H'O')      +      C"H'=0'-,  2  aq. 


Gallo-taaaic  acid.  Galic  acid.  Glucose. 

3H0,  C»H'0'     =     C'lPO"     -t-     2C0* 


<3allic  acid.  Pj-rosallic  acid. 

When  powdered  nut-galls  are  made  into  a  paste,  with  water,  and  allowed  to  ferment  for 
some  considerable  time,  with  occasional  stirring  to  facilitate  the  absorption  of  oxygen,  the 
gallo-tannic  acid  is  almost  entirely  converted  into  gallic  acid. 

1  eq.  tannic  acid  C"H"0'^ )        (    3  eq.  gallic  acid         C'-IP'O^ 

\  =  \    -1  eq.  water  II'  0* 

24  eq.  oxygen  0"*)        (  12  eq.  carbonic  acid    C'-      0"* 


TAN'yiN'G.  There  have  been  several  patents  for  quickening  the  tanning  process,  but 
we  shall  mention  only  one  or  two  here. 

The  following  is  taken  from  the  Bavarian  Journal  of  Arts  and  Trades,  and  is  known  as 
Knodcrer's  tanning- process. 

It  is  well  known  that  the  absence  of  atmospheric  air  greatly  facilitates  the  process  of 
tanning,  and  in  order  to  effect  this  the  process  must  be  carried  on  in  vacuo. 

The  vessel,  in  which  the  tanning  substance  is  kept,  has  to  be  made  air-tight,  and  at  the 
same  time  no  metal  can  be  used  but  the  expensive  one,  copper.  Iron,  :us  well  a.s  zinc,  is 
aflfected  by  the  tanning  substance,  and  wood  can  only  be  used  when  its  pores  have  been 
stopped  by  some  varnish  which  elfectually  prevents  the  passage  of  air  into  the  vessel. 

The  process  is  carried  on  as  follows: — When  the  hides  are  taken  from  the  wash,  all  the 
water  contained  in  them  is  expelled  by  a  powciful  press.  They  are  then  |)laccd  in  a  barrel, 
having  a  rotatory  motion,  together  with  the  necessary  amount  of  tanning  material,  and 
enough  water  added  to  keep  the  contents  of  the  barrel  moist. 

The  man-hole  is  now  clo.sed,  and  the  air  pumped  out  as  completely  as  possible ;  this 
being  done,  the  stop-cock  is  closcii,  and  a  piece  of  lead  pipe  is  added  to  the  conducting  tube ; 
this  lead  i)ipe  communicates  with  a  tank  which  contains  tanning  fluid  of  proper  strength. 


1044  TANNING. 

If  the  stop-cock  !g  now  opened,  the  tanning  fluid  rushes  rapidly  into  the  barrel,  and  when  a 
sutlicient  quantity  has. been  admitted,  the  stop-cocli;  is  closed,  and  the  barrel  is  now  rotated 
for  an  hour,  or  half  an  hour,  according  to  the  quantity  of  hides  contained  in  it.  After  two 
or  three  hours'  rest,  the  rotation  is  again  continued  to  the  end  of  the  operation. 

The  advantages  of  this  process  are :  First,  by  the  air  being  rarefied  the  pores  of  the  skins 
are  opened,  and  thus  more  rapidly  absorb  the  tanning  principle ;  and  the  tannic  acid  is  not 
so  rapidly  converted  into  gallic  acid,  which  is  of  no  use  in  tanning. 

Secondly,  the  rotatory  motion  facilitates  the  extraction  of  the  tannic  acid  from  the  bark 
&c.  Thus  the  hides  are  completely  tanned  in  a  much  less  time  than  without  rotatory  mo- 
tion, as  will  be  seen  by  the  following  table,  based  on  actual  experiments. 

Time  required  for  tanning,  Time  required  when 

in  vacuo,  without  motion.  motion  is  employed. 

Calf  skins         -         -         from  6  to  1 1  days.  •         -  4  to  7  days. 

Horse  hides     -         -  35       40  -         -         14     18 

Light  cow  hides       -  30       35  --1216 

Cow  bides  (middling)  40      45  -         -         18     20 

Heavy  cow  hides      -  50       60  -         -         22     SO 

Ox  hides  (light)        -  50       60  -         -         20     SO 

Ox  hides  (first  quality)  70       90  -         -         35     40 

At  the  same  time  a  large  percentage  of  bark  is  saved. 

A  patent  was  taken  out  by  E.  Welsford,  of  Bona,  Algeria,  in  1859.  Instead  of  employ- 
ing oak  bark  or  the  ordinary  tanning  substances,  he  uses  the  leaves  of  the  different  trees 
and  shrubs  of  the  femily  Tcrebinthacece,  as  the  Pistacea  tcrebinthus,  Pi.stacca  Atlantica, 
Pistacea  lentixcus,  &c.,  abounding  on  the  coast  of  the  Mediterranean  and  clsewher.e.  He 
forms  an  infusion  or  decoction  of  the  leaves  for  tanning. 

A  machine  has  been  invented  by  Mr.  S.  F.  Cox,  of  Bristol,  for  effecting  the  various  pro- 
cesses of  depiling,  scudding,  striking,  smoothing,  sticking,  and  stretching,  which  are  now 
usually  effected  by  hand.  The  hide  or  skin  is  carried  by  a  cylinder  or  roller,  or  by  a  mov- 
ing bed  or  platform,  which  presents  it  gradually  to  a  revolving  spiral  bar  rib  knife  or  rubber. 
The  spiral  consists  of  a  right  and  left  handed  screw,  so  arranged  as  to  rub  or  scrape  the  hide, 
&c.  from  the  centre  toward  the  sides,  or  it  may  consist  of  a  single  thread  of  a  screw,  or 
several. 

The  roller  or  bed  which  carries  the  hide  or  skin  is  pressed  toward  the  revolving  spiral 
instruments  by  springs  or  otherwise,  and  is  gradually  advanced  by  a  ratchet,  so  that  the 
whole  of  the  hide  is  uniformly  and  successively  exposed  to  the  action  of  the  revolving  spiral 
instruments.  A  treadle  is  employed  for  withdrawing  the  roller  or  bed  from  the  revolving 
spiral  to  facilitate  the  adjustment  of  the  hide. 

Vegetable  Substances  used  in  Tanning. 

No  two  substances  will  produce  the  same  quality  leather,  either  in  texture  or  color. 
Doubtless  this  is  owing  to  a  different  variety  of  tannic  acid  contained  in  the  material,  though 
unfortunately  very  little  is  understood  about  it,  the  subject  not  having  been  much  studied. 
Some  things  contain  a  large  proportion  of  tannin  but  do  not  fill  up  the  pores  of  the  hide ; 
gambir,  for  instance,  tans  quickly,  but  'does  not  make  a  heavy  leather. 

Oak  bark,  {Qncrcus  pedunculata.) — This  bark  is  preferred  to  all  other  materials  for  tan- 
ning, since  it  produces  the  best  leather  for  most  purposes.  The  oak  bark  of  this  country  is 
considered  superior  to  that  of  any  other  part  of  Europe.  The  bark  season  in  England  is 
usually  from  the  middle  of  April  to  the  end  of  May.  It  is  essential  that  the  sap  should  run 
well  before  the  bark  is  stripped,  as  it  contains  most  tannin  when  the  sap  begins  to  run. 

Enc/lixh  coppice  oak  bark. — This  bark  is  very  similar  to  timber  oak  bark,  Ijut  is  lighter 
and  thinner,  and  contains  more  tannin,  as  there  is  not  so  much  epidermis,  (which  contains 
none.)  It  is  preferred  for  tanning  light  goods.  Coppice  bark  is  stripped  at  the  same  time 
of  year  as  the  heavier  sorts. 

Belcjium  oak  bark. — This  bark  is  similar  to  the  English,  and  is  imported,  chopped  into 
small  pieces,  chiefly  from  Antwerp ;  it  docs  not  sell  for  so  high  a  price  as  the  English,  for 
it  is  said  not  to  contain  so  much  tannin. 

Chopped  bark  is  simply  bark  with  the  rough  epidermis  scraped  off  and  then  chopped 
into  pieces. 

Cork-tree  bark,  [Qiiercus  subcr.) — This  is  the  inner  bark  of  the  cork  tree,  the  cork  gi'ow- 
ing  on  the  exterior  contains  no  tannin.  If  is  imported  from  the  Island  of  Sardinia,  Tuscany, 
and  the  coast  of  Africa ;  the  Sardinian  is  the  best,  and  may  easily  be  distinguished  by  its 
color  and  weight,  being  of  a  pinkish  hue  throughout,  and  is  stouter  and  heavier  than  the 
Tuscan  or  African.  Cork-tree  bark  contains  a  great  deal  of  tannin,  but  deposits  little 
"  bloom"  cm  the  leather. 

There  are  four  species  of  oak  chiefly  used  for  tanning  in  America.  Spanish  oak  bark  is 
thick,  black,  and  deeply  furrowed,  and  is  preferred  for  coarse  leather.  In  the  Southern 
States  the  Spanish  oak  grows  to  the  height  of  80  feet  with  a  diameter  of  4  or  5  feet  at  the 
trunk,  wliile  in  the  North  it  does  not  exceed  the  height  of  30  feet. 


TEA,  1045 

The  common  red  oak,  abundant  in  Canada  and  in  the  Northern  States,  is  very  generally 
employed,  though  inferior  in  several  respects  to  the  other  kinds. 

2'Ae  rock  chestnut  oak  abounds  in  elevated  districts.  On  some  of  the  Alleghany  moun- 
tains it  constitutes  nine-tenths  of  the  forest  growth ;  its  bark  is  thick,  hard,  and  deeply  fur- 
rowed, but  only  the  bark  of  the  small  branches  and  young  trees  is  used  in  tanning. 

Quercitron  hark,{Qurrcuii  thicloria,)  or  black  oak,  grows  through  th-^  States;  its  bark 
is  not  very  thick,  l)ut  deeply  furrowed,  and  of  a  deep  brown  color ;  the  leather  tanned  with 
it  is  apt  to  tinge  the  stockings  yellow.  This  tree  often  attains  a  height  of  90  feet,  and  a 
diameter  of  4  or  5  feet. 

There  are  other  varieties  used,  but  it  is  needless  to  mention  them  here. 

Valonia,  {Quercus  cEjrtVops.)— Valouia  is  the  acorn  cup  of  the  Quercus  cegilops.  Sec 
Leather. 

Sumac  of  commerce  is  the  crushed  or  ground  leaves  of  lihus  corriaria,  and  is  imported 
from  Sicily.  In  making  the  usual  ground  sumac  the  larger  branches  or  sticks  are  taken  out 
by  hand ;  the  smaller  ones  do  not  pulverize,  and  are  taken  out  by  sifting,  the  stem  of  the 
leaves  are  put  under  the  mill  a  second  time.  In  grinding,  the  calculation  is  that  333  lbs.  of 
leaves  turn  out  280  lbs.  of  fine  ground  sumac. 

There  is  naturally,  or  at  least  unavoidably,  from  3  to  4  per  cent,  of  sand  or  dirt  in  the 
leaves  as  sent  to  the  mill ;  this  can  only  be  taken  out  before  grinding,  but  if  thoroughly  done 
would  cost  Is.  6(7.  per  cwt.  additional,  which  the  trade  will  not  pay. 

Mimosa  bark  is  the  bark  of  a  tree  belonging  to  the  order  Fabacew,  subdivision  Mimosce. 
It  is  imported  from  Australia  and  Tasmania,  but  is  also  abundant  in  the  East  Indies.  Mi- 
mosa bark  is  difificult  to  grind,  it  is  also  difficult  to  extract  the  tannin;  it  deposits  no  bloom, 
and  is,  therefore,  not  much  esteemed  by  English  tanners,  but  is  used  in  the  East  Indies  to 
a  large  extent. 

Gambir,  or  terra  japonica. — This  astringent  substance,  sometimes  called  catechu,  is 
produced  by  boiling  and  evaporating  the  brown  hard  wood  of  the  acacia  catechu  in  water, 
until  the  inspissated  juice  has  acquired  a  proper  consistency ;  the  liquor  is  then  strained, 
and  soon  coagulates  into  a  mass. 

It  is  frequently  mixed  with  sand  and  other  impurities,  has  little  smell,  but  a  sweet  as- 
tringent taste  in  the  mouth,  and  is  gritty  if  it  is  perfectly  pure ;  it  will  totally  dissolve  in 
water,  and  the  impurities  will  fall  to  the  bottom.  It  is  chiefly  used  in  England  as  in  the 
East  Indies  (whence  it  is  imported)  for  tanning  kips.     It  is  mixed  with  valonia  and  sumac. 

Larch  bark  is  used  for  tanning  basils  (sheepskins)  for  bookbinding,  &c.,  principally  in 
Scotland,  where  the  bark  is  more  abundant,  though  it  is  also  used  in  England  and  Ireland. 

Birch  bark  is  used  for  tanning  Russia  leather ;  it  is  also  used  by  the  Laplanders. 

Hemlock  bark  {Abies  Canadensis)  is  one  of  the  principal  barks  used  in  America  for 
tanning ;  it  makes  a  reddish  colored  leather,  and  not  nearly  so  good  as  oak  bark  leather. 

There  is  a  large  collection  of  tanning  materials  in  the  Museum  at  the  Royal  Gardens  at 
Kew,  collected  by  Mr.  W.  G.  Fry  of  Bristol,  to  whom  we  are  indebted  for  the  practical  part 
of  this  paper. — H.  K.  B. 

TARE,  or  VETCH,  a  plant — Vicia  saliva — which  has  been  cultivated  in  this  country 
from  the  earliest  times. 

TARTRATES  are  bibasic  salts  composed  of  tartaric  acid  and  oxidized  bases,  in  equiva- 
lent proportions.  Some  of  the  tartrates  are  employed  in  the  arts,  bitartrate  of  potash  being 
used  as  a  mordant  in  dyeing  woollen  fabrics.  Tartrate  of  chromium  is  sometimes  used  in 
calico  printing,  and  the  tartrate  of  potash  and  tin  in  wool  dyeing. 

The  Stockholm  tar  is  regarded  as  the  ))est ;  we  have  a  description  of  the  mode  in  which 
it  is  prepared,  by  Dr.  Clai'ke,  in  his  Travels  in  Scandinavia. 

"  The  situation  most  favorable  to  the  process  is  in  a  forest  near  to  a  marsh  or  bog,  be- 
cause tiie  roots  of  the  fir,  from  which  tar  is  principally  extracted,  are  always  most  produc- 
tive in  such  places.  A  conical  cavity  is  then  made  in  the  ground,  (generally  on  the  side  of  a 
bank  or  sloi)ing  hill,)  and  tlie  roots  of  the  fir,  togethei'  witli  logs  and  billets  of  the  same, 
being  neatly  trussed  in  a  stack  of  the  same  conical  shape,  aio  let  into  the  cavity.  The  whole 
is  then  covered  with  turf  to  prevent  the  volatile  parts  from  l)eing  di8sii)ated,  wiiich,  by 
means  of  a  heavy  wooden  mallet  and  wooden  stamper,  woiked  separately  by  two  men,  is 
beaten  down  and  reudei'ed  as  firm  as  possible  about  the  wood.  Tiie  stack  of  billets  is  then 
kindled,  and  a  slow  comliustion  of  the  fir  takes  place  as  in  working  charcoal.  During  this 
combustion  the  tar  exudes,  and  a  cast-iron  \ym\  lieing  at  the  bottom  of  the  funnel,  with  a 
spout  whicli  projects  through  tlie  side  of  the  liank,  barrels  are  placed  beneatii  this  spout  to 
collect  the  fluid  as  it  comes  away.  As  fast  as  the  barrels  are  filled  they  are  bunged  and 
ready  for  immediate  exportation. 

Wood  tar  is  obtained  as  a  secondary  product  in  the  manufacture  of  acetic  acid,  in  the 
dry  distillation  of  wood. 

TEA.  The  observations  of  Liebig  aflord  a  satisfactory  explanation  of  the  cause  of  the 
great  partiality  of  the  poor,  not  only  for  tea,  but  for  tea  of  an  expensive  and  su])erior  kind, 
lie  !-ays  :    "  We  shall  never  certainly  be  ulile  to  discover  how  men  were  first  led  to  the  use 


10i6 


TENT. 


of  the  hot  infusion  of  the  leaves  of  a  certain  shrub,  (tea,)  or  of  a  decoction  of  certain  roasted 
seeds,  (coffee.)  Some  cause  there  must  be  which  will  explain  how  the  practice  has  become 
a  necessary  of  life  to  all  nations.  But  it  is  still  more  remarkable,  that  the  beneficial  effects 
of  both  plants  on  the  hcaltli  must  be  ascribed  to  one  and  the  same  substance,  {theine  or  caffe- 
ine,) the  presence  of  wliich  in  two  vegetables,  belonging  to  natural  families,  the  products  of 
different  quarters  of  the  globe,  could  hardly  have  presented  itself  to  the  boldest  imagination. 
Yet  recent  researches  have  shown,  in  such  a  manner  as  to  exclude  all  doubt,  that  theine  and 
caffeine  are  in  all  respects  identical."  And  he  adds,  "  That  we  may  consider  these  vegeta- 
ble compounds,  so  remarkable  for  their  action  on  the  brain,  and  the  substance  of  the  oigans 
of  motion,  as  elements  of  food  for  organs  as  yet  unknown,  which  are  destined  to  convert 
the  blood  into  nervous  substance,  and  thus  recruit  the  energy  of  the  moving  and  thinking 
faculties."  Such  a  discovery  gives  great  importance  to  tea  and  coffee,  in  a  physiological 
and  medical  point  of  view. 

At  a  meeting  of  the  Academy  of  Sciences,  in  Paris,  lately  held,  M,  Peligot  read  a  paper 
on  the  Chemical  Combinations  of  Tea.  He  stated,  that  tea  contained  epsential  principles  of 
nutrition,  far  exceeding  in  importance  its  stimulating  properties :  and  showed  that  tea  is,  in 
every  respect,  one  of  the  mo.st  desirable  articles  of  general  use.  One  of  his  experiments  on 
the  nutritious  qualities  of  tea,  as  compared  with  those  of  soup,  was  decidedly  in  favor  of  the 
former. 

TEXT.  "We  have  no  space  to  enter  into  the  history  of  tents,  or  describe  the  varieties 
which  have  been  used  from  time  to  time.     A  few  words  on  modern  tents  must  suffice  : — 

'J'lic  hospital  tnnrqnee  is  29  feet  long,  and  14^  feet  wide  and  15  feet  liigh.  This  is  sup- 
posed to  accommodate  not  less  than  eighteen  nor  more  than  twenty-four  men.  The  height 
of  each  tent  pole  is  13  feet  8  inches;  the  length  of  the  ridgepole,  13  feet  10  inches;  the 
height  of  the  tent  walls  from  the  ground,  5  feet  4  inches.  The  weight  of  all  the  material 
of  such  a  tent  is  stated  by  Slajor  Rhodes  to  be  652  lbs. 

Of  the  circular  siufile-poleJ  tents  we  have  two  kinds,  the  new  cotton  circular  tent,  and 
the  new  pattern  linen  circular  tent ;  each  tent  is  provided  with  a  vertical  circular  wall ;  that 
of  the  cotton  tent  is  2  feet  6  inches  in  height,  and  that  of  the  linen  tent  is  1  foot.  The 
diameter  of  each  tent  is  12  feet  C  inches;  the  length  of  the  pole  about  10  feet.  Such  a 
tent  accommodates  sixteen  men. 

Major  Godfrey  Rhodes  has  introduced  a  new  and  improved  tent,  which  has  no  centre- 
pole.  The  frame  of  the  tent  is  formed  of  stout  ribs  of  ash,  bamboo,  or  other  flexible  ma- 
terial. The  endrz  of  the  ribs  are  inserted  into  a  wooden  head,  fitted  with  iron  sockets,  and 
tiic  butts  are  thrust  into  the  ground,  passing  through  a  double  twisted  rope,  having  fixed 
loops  at  equal  distances.  The  canvas  is  thrown  over  this  frame-work,  and  secured  within 
the  tent  by  leather  straps  to  the  ground,  or  circular  rope.  The  present  hospital  tent,  when 
pitched,  covers  about  340  square  yards.  Major  Rhodes'  hospital  tent  covers  only  03  square 
yards,  and  weighs  395  lbs.,  while  it  accommodates  an  equal  number  of  men.  The  field  tent 
is  made  up  in  one  package,  5  feet  B  inches  long,  weighing  100  lbs. ;  the  guard  tent  into  one 
package,  7  feet  6  inches  long,  weighing  52  lbs.     The  accompanying  cuts,  Jir/s.  046  and  647, 


C46 


TENT. 


1047 


show  Major  Rhodes'  field  tent  and  the  frame  thereof.     The  difference,  as  it  regards  weiglit 
and  convenience,  in  those  tents  introduced  by  Major  Rhodes,  is  very  great.     We  regret  our 
"  space  will  not  admit  of  more  detail ;  this,  however,  is  somewhat  compensated  by  the  ample 
detail  to  be  found  in  a  book,  Tents  and  Tent  Life,  published  by  the  patentee. 


The  ventilation  of  tents  has  been  admirably  effected  by  Mr.  Doyle,  to  whom  we  are  m- 
debted  for  the  information  contained  in  the  following  notes  on  the  subicct  :— 

The  old  method  of  ventilating  military  tents  was  very  defective.  Vent.latmg  opemngs 
were  made  at  the  top  of  the  tent,  but  no  means  were  provided  for  the  admission  of  fresh  air. 
The  result  was  mo.st  unsatisfactory,  as  may  be  gathered  from  the  following  evidence  given 
before  the  Sebastopol  committee : —  ,       i  •         ^         .t 

"  The  tents  were  very  close  indeed  at  night.    When  the  tent  was  closed  in  wet  weather, 
it  was  often  past  bearing.     The  men  became  faint  from  heat  and  closeness. 
*  Evidence  of  Sergeant  Dawson.  Grenadier  Guiirds. 


1048  TERRA  COTTA. 

The  problem  then  was  to  let  in  fresh  air,  and  produce  a  draft  without  inconveniencing 
the  soldiers  as  they  slept. 

The  question  attracted  Mr.  Doyle's  notice  during  the  period  of  the  cafap  at  Chobham, ' 

and  it  appearing  to  him  to  be  one  of  very  great  importance,  he  undertook,  with  the  sanction 

of  Lord  llaglan,  then  Master-General  of  the  Ordnance,  to  try  the  following  experiment : — 

lie  caused  two  openings  to  be  made  in  the  wall  of  a  tent,  about 

6"^^  a/        4  feet  from  the  ground,  and  introduced  the  air  between  the  wall  and 

/  a  piece  of  lining  somewhat  resembling  a  carriage  pocket,  fy.  648  : 

/  a  a,  is  the  wall  of  the  tent ;  6,  the  opening  to  admit  air  ;  c,  the  lining. 

/ -^  It  will  be  seen  that  air  so  introduced  would  naturally  take  an  up- 

/         ,'''      ward  direction,  and  that  this  communicating  with  the  openings  at 
/       ,/  the  top  of  the  tent,  would  probably  produce  the  desired  effect. 

/      /'  The  following  extract  from  the  report  on  this  experiment  will 

/     ,/  show  the  actual  result : — 

^k/    /  "  The  ventilators  (Mr.  Doyle's)  were  found  of  great  use  in  clear- 

i^2-''  ing  the  tent  of  the  fetid  atmosphere  consequent  upon  a  number  of 

tt/  men  sleeping  in  so  confined  a  space.     The  men  state  that  the  heavy 

smell  experienced  before  the  tent  was  altered  is  almost  banished." 

In  subsequent  experiments  the  number  of  the  new  openings  was  increased  from  two  to 
three,  and  a  greater  amount  of  ventilation  thus  obtained.  The  result,  according  to  an  offi- 
cial letter  of  thanks  received  on  the  subject,  was  "  quite  successful."  The  imjiiovement  has 
been  since  adopted  into  the  service,  and  by  these  very  simple  means  one  of  the  most  fruit- 
ful causes  of  sickness  among  our  soldiers  in  camp  finally  removed. 

TERRA-COTTA.  When  moulding  is  performed  for  terra-cotta  works,  sheets  of  clay 
are  beaten  on  a  bench  to  the  consistency  of  glazier's  putty,  and  pressed  by  the  hand  into 
the  mould  ;  according  to  the  magnitude  of  the  work  and  the  weight  it  may  hava  to  sustain, 
the  thickness  of  the  clay  is  determined  and  arranged,  and  here  consists  a  part  of  the  art  it 
would  be  impossible  to  describe,  and  which  requires  years  of  experience  in  such  works  to 
produce  great  works  and  fire  them  with  certainty  of  success.  At  the  Crystal  Palace,  Syden- 
ham, are  several  large  works  manufactured  by  Mr.  J.  M.  Blashfield,  who  has  extensive  terra- 
cotta works  at  Stamford.  The  figure  of  Australia,  modelled  by  John  Bele,  nine  feet  in 
height,  and  burnt  in  one  piece ;  the  colossal  Tritons  modelled  by  the  same  artist,  and  other 
works,  are  examples.  After  the  moulded  article  has  become  sufficiently  dry,  it  is  conveyed 
to  a  kiln.  A  slow  fire  is  first  made,  and  Cjuickened  until  the  heat  is  sufficient  to  blend  and 
partially  vitrify  the  material  of  which  the  mass  is  composed ;  when  sufficiently  baked,  the 
kiln  is  allowed  to  cool,  and  the  terra-cotta  is  withdrawn. 

TESSER.E.  The  Roman  tessera^,  of  which  many  very  fine  examples  have  been  discov- 
ered in  this  country,  were,  often,  natural  stones,  (sometimes  colored  artificially,)  but  gen- 
erally of  baked  clay.  The  beauty  of  many  of  these  has  led  to  the  production  of  modcrji 
imitations,  which  have  been  gradually  improved,  until,  in  the  final  result,  they  far  exceed 
any  work  of  the  Romans. 

About  half  a  century  since  Mr.  C.  "^^^yatt  obtained  a  patent  for  a  mode  of  imitating  tes- 
selatcd  pavements,  by  inlaying  stone  with  colored  cements.  Terra-cotta,  inlaid  with  colored 
cements,  has  also  been  employed,  but  with  no  very  marked  success. 

Mr.  IBIashfield  produced  imitations  of  those  pavements,  by  coloring  cements  with  the 
metallic  oxides :  these  stood  exceedingly  well  when  under  cover,  but  they  did  not  endure 
the  winter  frosts,  &-c.  Bitumen,  colored  with  metallic  oxides,  was  also  employed  by  Mr. 
Blashfield.  In  1839  Mr.  Singer,  of  Vauxhall,  introduced  a  mode  of  forming  tesserfe  from 
thin  layers  of  clay.  These  vrere  cut  into  the  required  forms,  dried  and  baked.  In  1840 
Mr.  Prosser,  of  Birmingham,  discovered  that  if  the  material  of  porcelain  (cliina  clay)  be 
reduced  to  a  dry  powder,  and  in  that  state  be  compressed  between  steel  dies,  the  powder  is 
condensed  into  about  a  fourth  of  its  bulk,  and  is  converted  into  a  compact  solid  substance 
of  extraordinary  hardness  and  density. 

This  process  was  first  applied  to  the  manufacture  of  buttons,  but  was  eventually  taken 
up  by  Mr.  Minton  and,  in  conjunction  with  Mr.  Blashfield,  Messrs.  Wyatt,  Parker  «t  Co.,  was 
carried  to  a  high  degree  of  perfection  for  making  tesserae. 

The  new  process,  invented  by  Mr.  Prosser,  avoided  the  difficulty  altogether  of  using  wet 
clay. 

This  change  in  the  order  of  the  potter's  operations,  although  very  simple  in  idea,  (and  a 
sufficiently  obvious  result  of  reflection  on  the  difficulties  attending  the  usual  course  of  pro- 
cedure,) lias  nevertheless  required  a  long  series  of  careful  experiments  to  find  out  the  means 
of  rendering  it  available  in  practice. 

The  power  which  the  hand  of  the  potter  has  exercised  over  his  clay  has  been  proverbial 
from  time  immemorial,  but  it  is  limited  to  clay  in  its  moist  or  plastic  state  ;  and  clay  in  its 
powdered  state  is  an  untractable  material,  requiring  very  exact  and  powerful  machinery  to 
W  Fubstitutod  for  the  hand  of  the  potter  ;  in  order,  by  great  pressure,  to  obtain  the  requi- 
siti'  ( olicsion  of  the  particles  of  clay. 


TESSEE^. 


1049 


In  the  new  process,  the  clay,  or  earthy  material,  after  being  prepared  in  the  usual  man- 
ner, and  brought  to  tlie  plastic  state,  as  above  described,  (except  tliat  no  kneading  or  tem- 
pering is  requisite,)  is  formed  into  lumps,  which  are  dried  until  tlie  water  is  evaporated  from 
the  clay. 

The  lumps  of  dried  clay  are  then  broken  into  pieces,  small  enough  to  be  ground  by  a 
suitable  mill  into  a  state  of  powder,  which  is  afterward  sifted,  in  order  to  separate  all  coarse 
grains  and  obtain  a  fine  powder,  which  it  is  desirable  should  consist  of  particles  of  uniform 
size  as  nearly  as  can  be  obtained.  The  powder,  so  prepared,  is  the  state  in  which  the  clay 
is  ready  for  being  moulded  into  the  form  of  the  intended  article  by  the  new  process. 

The  machine  and  mould  used  for  moulding  articles  of  a  small  size,  in  powdered  clay,  are 
represented  in  the  annexed  drawing,  wherein  fig.  649  is  a  lateral  elevation  of  the  whole 
machine. 

A  A  is  the  wooden  bench  or  table  whereon  the  whole  is  fixed,  that  bench  being  sustained 
on  legs  standing  on  the  floor,  b  d  e  is  the  frame,  formed  in  one  piece  of  cast  iron  ;  the 
base  B  standing  on  the  bench,  and  being  fixed  thereto  by  screw  bolts ;  the  upright  stand- 
ard D  rising  from  the  base,  and  sustaining  at  its  upper  end  the  boss  e,  wherein  the  nut  or 
box  a  is  fixed  for  the  reception  of  the  vertical  screw  f      The  screw  f  works  through  the 


649 


r\ 


box  a,  and  has  a  handle,  G,  g,  li,  applied  on  the  upper  end  of  the  screw ;  the  handle  is 
bent  downward  at  g,  to  bring  the  actual  handle  /;  to  a  suitable  height  for  the  person  who 
works  that  machine  to  grasp  the  handle  h  in  his  right  hand,  and,  by  pulling  the  handle  h 


1050 


TESSERA. 


toward  him,  the  screw  f  is  turned  round  in  its  box,  a,  and  descends.  The  lower  end  of 
the  screw  f  is  connected  with  a  square  vertical  slider,  h,  which  is  fitted  into  a  socket,  i, 
fixed  to  the  upiiglit  part  D  of  the  frame,  and  the  slider  ii  is  thereby  confined  to  move  up 
or  down,  with  an  exactly  vertical  motion,  when  it  is  actuated  by  the  screw,  without  devia- 
tion from  the  vertical. 

Thus  far  the  machine  is  an  ordinary  screw  press,  such  as  is  commonly  used  for  cutting 
and  compressing  metals  for  various  purposes.  The  tools  with  which  the  press  is  furnished 
for  the  purpose  of  this  new  process  consist  of  a  hollow  mould,  e  c,  formed  of  steel,  the  ex- 
terior cavity  of  the  mould  being  the  exact  size  of  the  article  which  is  to  be  moulded.  The 
mould  c  e  is  firmly  fixed  on  the  base  d  of  the  frame,  so  as  to  be  exactly  beneath  the  lower 
end  of  the  piston,  a,  or  plug,  /,  which  is  fastened  to  the  lower  end  of  the  square  slider  h, 
and  the  plug  /  is  adapted  to  descend  into  the  hollow  of  the  mould  e  e,  when  the  slider  h 
is  forced  downward  by  action  of  the  screw  f,  the  plug  f  being  very  exactly  fitted  to  the 
interior  of  the  mould  e  e. 

The  bottom  of  the  mould  e  e  is  a  movable  piece,  n,  which  is  exactly  fitted  into  the 
interior  of  the  mould,  but  which  lies  at  rest  in  the  bottom  of  the  mould  e  e,  during  the 
operation  of  moulding  the  article  therein  ;  but  afterward  the  movable  bottom  ii  can  be 
raised  up  by  pressing  one  foot  upon  one  end,  r,  of  a  pedal  lever,  r  s,  the  fulcrum  of  which 
is  a  centre  pin,  r,  supported  in  a  standard  resting  upon  the  floor,  and  the  end  s  of  the 
lever  operates  on  an  upright  rod,  in,  which  is  attached  at  its  upper  end  to  the  movable  bot- 
tom 71  of  the  mould  e  e. 

A  small  horizontal  table,  T  T,  is  fixed  round  the  mould  e  c,  and  on  that  table  a  quantity 
of  powdered  clay  is  laid  in  a  lump  in  readiness  for  filling  the  mould. 

The  two  detached  figures,  marked  Ji(/s.  650  and  651,  are  sections  of  the  mould  e  e,  and 
the  plug  /,  on  a  larger  scale  than  fff.  049,  in  order  to  exhibit  their  action  more  com- 
pletely. 

The  operation  is  extremely  simple  ;  the  operator,  holding  the  handle  h  with  his  right 
hand,  puts  it  back  from  him,  so  as  to  turn  back  the  screw  f,  and  raise  the  slider  h,  and 
the  plug  /,  quite  out  of  the  mould  e  e,  and  clear  above  the  orifice  of  the  mould,  as  shown 
in  Jiff.  019. 

Then  with  a  spatula  of  bone,  held  in  the  left  hand,  a  small  quantity  of  the  powder  is 
moved  laterally  from  the  heap,  along  the  surface  of  the  table  x  t,  toward  the  mould  e  e, 
and  gathered  into  the  hollow  of  the  mould  with  a  quiet  motion,  so  as  to  fill  that  hollow  very 
completely,  and  by  scraping  the  spatula  evenly  across  over  the  top  of  the  mould  e  e,  the 
superfluous  powder  will  be  removed,  leaving  the  hollow  cavity  of  the  mould  exactly  filled 
with  the  powder  in  a  loose  state,  and  neither  more  nor  less  than  filled. 

Then  the  handle  //,  being  drawn  forward  with  a  gentle  movement  of  the  right  hand,  it 
turns  the  screw  f,  so  as  to  bring  the  slider  n,  and  the  plug  /,  which  thereby  descends  into 
the  mould  e  e,  upon  the  loose  powder  wherewith  the  mould  has  been  filled,  and  begins  to 
press  down  that  powder,  which  must  be  done  with  a  gentle  motion  without  any  jerk,  in 
order  to  allow  the  air  that  is  contained  in  the  loose  powder  to  make  its  escape  ;  but  the 
pressure,  after  having  been  commenced  gradually,  is  continued  and  augmented  to  a  great 
force,  by  pulling  the  handle  strongly  at  the  last,  so  as  to  compress  the  earthy  jnaterial  down 
upon  the  bottom  n  of  the  mould,  into  about  one  third  the  space  it  had  occupied  when  it 
was  in  the  state  of  loose  powder.  The  section,  jig.  050,  shows  this  state  of.  the  mould  e  e, 
and  the  plug  /,  and  the  compressed  material. 

Then  the  handle  h  is  put  backward  again,  so  as  to  turn  back  the  screw  f,  and  raise  up 
the  slider  h,  and  the  plug  /,  until  the  latter  is  drawn  up  out  of  the  mould  e  c,  and  clear 
above  the  orifice  of  the  mould,  as  in  fir/.  049,  and  immediately  afterward  by  jn-cssure  of  one 
foot  on  the  pedal  u  of  the  pedal  lever  R,  S,  and  by  action  of  the  right  rod  in,  the  mov- 
able bottom  n  of  the  mould  is  raised  upward  in  the  mould  e  e,  so  as  to  elevate  the  com- 
pressed material  which  is  resting  upon  the  bottom  n,  and  carry  the  same  upward,  quite  out 
of  the  mould  e  e,  and  above  the  orifice  of  the  mould,  as  is  shown  in  Jig.  651,  and  then  the 
compressed  material  can  be  removed  by  the  finger  and  thumb. 

The  compressed  material  which  is  so  withdrawn  is  a  solid  body,  retaining  the  exact  shape 
and  size  of  the  interior  cavity  of  the  mould,  and  possessing  sufiicient  coherence  to  enable  it 
to  endure  as  much  handling  as  is  requisite  for  putting  a  number  of  them  into  an  earthen- 
ware case  or  pan,  called  a  sagger,  in  which  they  are  to  be  enclosed,  according  to  the  usual 
practice  of  potters,  in  preparation  for  putting  them  into  the  potter's  kiln  for  firing  ;  the  sag- 
ger protects  tlie  articles  from  discoloration  by  smoke,  and  frotn  partial  action  of  the  flame, 
which,  if  a  number  of  small  articles  were  exposed  thereto,  without  being  so  enclosed,  might 
operate  more  strongly  upon  some  than  upon  others  of  those  articles ;  but  by  means  of  the 
snggcrs  the  heat  is  caused  to  operate  with  clearness,  uniformity,  and  certainty  upon  a  num- 
ber of  small  articles  at  once. 

After  the  firing  is  over,  the  articles,  being  removed  from  the  saggers,  are  in  the  state  of 
what  is  termed  biscuit,  and  are  ready  for  use,  unless  they  are  required  to  be  glazed,  in  which 
case  they  may  be  dipped  into  a  semi-liquid  composition  of  siliceous  and  other  matters,  ground 


TIN  PLATES.  1051 

ia  water  to  the  consistency  of  cream,  and  the  surface  of  the  articles  which  are  so  dipped 
becomes  covered  with  a  thin  coating  of  the  glazed  composition,  and  then  the  articles  are 
again  put  into  saggers,  and  subjected  to  a  second  operation  of  firing  in  another  kiln,  the 
heat  whereof  vitrities  the  composition  and  gives  a  glassy  surface  to  the  articles,  all  which  is 
the  usual  course  of  making  glazed  eartlienware  or  porcelain  ;  but  for  articles  formed  by  the 
new  process,  a  suitable  glazing  composition  is  more  usually  applied  within  the  saggers,  into 
which  the  articles  are  put' for  the  first  firing,  and  the  glazing  is  performed  at  the  same  time 
with  the  first  burning,  without  any  other  burning  being  required.  Or,  in  other  cases,  the 
composition  of  earthy  materials  which  is  chosen  for  the  articles  may  be  such  as  will  become 
partially  vitrified  by  the  heat  to  which  they  are  exposed  in  the  kiln,  and  thereby  external 
glazing  is  rendered  unnecessary. 

The  great  contraction  whicla  must  take  place  in  drying  articles  which  have  been  moulded 
from  clay  in  the  moist  state  is  altogether  prevented,  and  consequently  all  uncertainty  in  the 
extent  of  that  contraction  is  avoided.  Tiles,  tesserse,  and  other  articles  are  now  made  by 
this  machine  ;  and  very  beautiful  pavements  are  constructed,  excelling  the  finest  works  of 
the  Romans  in  form,  in  color,  and  in  all  the  mechanical  conditions. 

THEBAIXE.     C^'H^'XO-.     One  of  the  numerous  alkaloids  contained  in  opium. 

THIALDIXE.  C'-H"XS'.  A  curious  alkaloid,  formed  by  the  action  of  sulphuretted 
hydrogen  on  aldehvde  ammonia. 

THORIXUM  OR  THORIUM.  A  rare  metal  found  in  the  mineral  thorite  which  con- 
tains about  57  per  cent,  of  thorina,  the  oxide  of  this  metal. 

TIN  PLATES.  The  affinity  of  iron  for  tin  is  much  greater  than  is  generally  supposed. 
The  point  at  which  the  metals  cohere  is  no  doubt  an  actual  alloy ;  and  advantage  is  taken 
of  this  by  the  manufacturers  of  articles  for  domestic  use,  male  in  iron — as  bridle  bits,  com- 
mon stirrups,  small  nails,  &c.  When  the  imii,  whether  wroi  rht  or  cast,  is  perfectly  clean 
and  free  from  rust,  and  brought  in  contact  with  melted  tin,  at  a  high  temperature,  an  alloy 
seems  to  be  at  once  formed,  protecting  the  iron  from  oxidization  whilst  the  tin  lasts.  Many 
plans  are  used  for  tinning  iron  articles,  of  small  size,  by  the  manufacturers.  One  of  the 
common  methods  of  manufacturers  of  bridle  bits  and  small  ware,  in  South  Staffordshire,  is 
to  clean  the  surface  of  the  articles  to  be  tinned,  by  steeping  them  for  sufficient  time  in  a 
mixture  of  sulphuric  and  hydrochloric  acids,  diluted-  with  water,  then  washing  them  well 
with  water,  but  taking  great  care  they  do  not  rust,  at  once  placing  them  in  a  partially  closed 
stoneware  vessel,  (such  as  a  common  bottle,)  which  contains  a  mixture  of  tin  and  hydro- 
chlorate  of  ammonia.  This  vessel  is  then  placed  on  a  smith's  hearth,  duly  heated,  and  fre- 
quently agitated  to  sqcurc  the  complete  distribution  of  the  tin  over  the  iron.  The  articles, 
when  thus  tinned,  are  thrown  into  water  to  wash  away  all  remains  of  the  sal  ammoniac ; 
and  lastly,  cleaned  in  hot  bran,  or  sawdust,  to  improve  the  appearance  for  sale. 

The  plans  of  cleaning  and  preparing  the  iron  for  tinning  have  undergone  many  changes 
in  the  past  century.  About  1720  the  plan  for  cleaning  was  to  scour  the  plates  with  sand 
and  water,  and  file  off  the  rough  parts,  then  cover  with  resin,  and  dip  them  in  the  melted 
tin.  About  1747  the  plates  were,  after  being  cold  rolled,  soaked  for  a  week  in  the  lees  of 
bran,  which  had  been  allowed  to  stand  in  water  about  ten  days,  to  become,  by  fermentation, 
sufficiently  acid,  and  then  scoured  with  sand  and  water.  In  1760  the  plates  were  pickled  in 
dilute  hydrochloric  acid  before  annealing,  and  cleaned  with  dilute  sulphuric  acid  after  being 
taken  out  of  the  bran  lees.  An  improvement  of  great  importance  in  this  process  was  made 
about  1715  ;  the  inventor  seems  to  have  been  Mr.  Mosely,  who  carried  on  tin  plate  works 
in  South  Staffbrdshire.  This  invention  was  the  use  of  the  grease  pot,  and  in  this  department 
little,  if  any,  improvement  has  since  been  made.  The  plan  was  introduced  into  South  Wales 
in  1717  by  Mr.  John  Jenkins,  and  his  descendants  are  still  amongst  the  principal  manuf\ic- 
turers  in  the  trade.  The  process  of  cleaning  and  tinning  at  some  of  the  best  works  now  is 
as  follows : — When  the  sheet  iron  leaves  the  plate  mill,  and  after  separating  the  plates,  and 
sprinkling  between  each  plate  a  little  sawdust,  the  effect  of  which  is  to  keep  them  separate, 
they  are  then  immersed,  or,  as  technically  termed,  "  pickled,"  in  dilute  sulphuric  acid,  and 
after  this  placed  in  the  annealing  pot,  and  left  in  the  furnace  about  24  liours  ;  on  coming 
out,  the  plates  are  p;issed  through  the  cold  rolls  ;  after  passing  the  cold  rollsi,  the  plates 
seem  to  have  too  much  the  character  of  steel,  and  are  not  sufficiently  ductile ;  to  remedy 
this  they  are  again  annealed  at  a  low  heat,  washed  in  dilute  sulphuric  acid,  to  remove  any 
scale  of  oxide  of  iron,  and  scoured  with  sand  and  water;  the  plates  in  this  state  require  to 
be  perfectly  clean  and  bright,  and  may  be  left  for  months  immei-sed  in  pure  water  without 
rust  or  injury  ;  but  a  few  minutes'  exposure  to  the  air  rusts  them.  With  great  care  to  have 
them  perfectly  clean,  they  are  taken  to  the  stow,  777.  652,  being  a  section  through  the  line 
K  K  of  the  plan  firi.  653.     Taken  from  right  to  left. 


1  represents  the  Tinman's  pan. 

2  "  the  Tin  pot 

3  "  the  Washing  or  dipping  pot. 
The  tinman's  pan  is  full  of  melted  grea.^e  :  in  this  the  plates  are  immersed,  and  left  there 
until  all  aqueous  moisture  upon  them  is  evaporated,  and  they  arc  con-plctclv  covered  wit' 


4  represents  the  Grease  pot. 

5  "  the  Cold  pot. 

6  "  the  List  pot. 


1052 


TIN  PLATES. 


652 


^t^_^ 


"Tl"! 


G53 


i^-- 


.->K--    tip 
1 


It  i; 


t     t 


11^ 


t^T 


the  grease ;  from  this  they  are  taken  to  the  tin  pot,  and  there  phmged  into  a  bath  of  melted 
tin,  which  is  covered  with  grease  ;  but  as  in  this  first  dipping  the  alloy  is  imperfect,  and  the 
surface  not  uniformly  covered,  the  plates  are  removed  to  the  dipping  or  wash  pot ;  this  con- 
tains a  bath  of  melted  tin  covered  with  grease,  and  is  divided  into  two  compartments.  In 
the  larger  compartments  the  plates  are  plunged,  and  left  sufficiently  long  to  make  the  alloy 
complete,  and  to  separate  any  superfluous  tin  which  may  have  adhered  to  the  surface ;  the 
workman  takes  the  plate  and  places  it  on  the  table  marked  b  on  the  plan,  and  wipes  it  on 
both  sides  with  a  brush  of  hemp ;  then  to  take  away  the  marks  of  the  brush,  and  give  a 
polish  to  the  surface,  he  dips  it  in  the  second  compartment  of  the  washpot.  This  last  always 
contains  the  purest  tin,  and  as  it  becomes  alloyed  with  the  iron  it  is  removed  on  to  the  first 
compartment,  and  after  to  the  tin  pot.  The  plate  is  now  removed  to  the  grease  pot  (No.  4) : 
this  is  filled  with  m.elted  grease,  and  requires  very  skilful  management  as  to  the  tempera- 
ture it  is  to  be  kept  at.  The  true  object  is  to  allow  any  superfluous  tin  to  run  off,  and  to 
prevent  the  alloy  on  the  surface  of  the  iron  plate  cooling  quicker  than  the  iron.  If  this 
were  neglected  the  face  of  the  plate  would  be  cracked.  The  plate  is  removed  to  the  cold 
pot  (No.  5) :  this  is  filled  with  tallow,  heated  to  a  comparatively  low  temperature.  The 
use  of  the  grease  pots,  Nos.  4  and  5,  is  the  process  adopted  in  practice  for  annealing  the 
alloyed  plates.  The  list  pot  (No.  6)  is  used  for  the  purpose  of  removing  a  small  wire  of 
tin,  which  adheres  to  the  lower  edge  of  the  plate  in  all  the  foregoing  processes.  It  is  a 
small  cast-iron  bath,  kept  at  a  sufficiently  high  ten,perature,  and  covered  with  tin  about 
one  fourth  of  an  inch  deep.  In  this  the  edges  of  the, plates  are  dipped,  and  left  until  the 
wire  of  tin  is  melted,  and  then  detached  by  a  quick  blow  on  the  plate  with  a  stick.  The 
plates  are  now  carefully  cleaned  with  bran  to  free  them  from  grease.  Lastly,  they  are  taken 
to  the  sorting  room,  where  every  plate  is  separately  examined  and  classed,  and  packed  in 
boxes  for  market  as  hereafter  described. 

The  tests  of  quality  for  tin  plates  are — ductility,  strength,  and  color.  To  obtain  these, 
the  iron  must  be  of  the  best  quality,  and  the  manufacture  must  be  conducted  with  propor- 
tionate skill.  This  necessity  will  explain  to  som.e  extent  the  cause  why  nearly  all  the  im- 
provements in  working  iron  during  the  past  century  lave  been  eitlicr  originated  or  first 
adopted  by  the  tin-plate  makers  ;  and  a  sketch  of  the  processes  used  at  difterent  times,  in 
working  iron  for  tin  plates,  will  be,  in  fact,  a  history  of  the  trade. 

The  process  of  preparing  the  best  or  charcoal  iron  seems  to  have  undergone  but  little 
change  from  1720  to  1607.  The  finery,  the  chaferv,  and  the  hammer  were  the  modes  of 
bringing  the  iron  from  the  pig  to  the  state  of  fini-shed  bars.  The  finery  was  of  the  exact 
form  of  the  ffi^.  054,  655,  650,  but  less  in  size  than  those  now  used.  The  chafery  or 
hollow  fire  was,  in  fact,  the  same  as  the  present  smitlis'  forge  fire,  but  on  a  larger  scale  ; 
and  the  "/(o//o?/t"  or  chamber,  in  which  the  bloom  was  heated,  was  made  by  coking  the 
coal  in  the  centre  with  the  blast,  and  taking  care  not  to  disturb  the  mass  of  coal  above, 
which  was  used  to  reverberate  the  heat  produced.  Both  the  finery  and  chafery  were  worked 
by  blast. 

The  hammers  were  of  two  descriptions :  the  forge  hammer,  a  heavy  mass  for  shaping 
the  blooms,  and  the  tilt  hammer,  much  lighter  and  driven  quicker,  for  shaping  the  bars. 

The  charge  for  the  finery  was  about  1  i  cwt.  of  pig  iron  :  this,  under  the  first  process, 
was  nducccl  to  \\  cwt.     It  was,  when  ready,  put  under  the  forge  hammer,  and  shaped  into 


TIN  PLATES. 


1053 


a  "  bloom,"  about  2  feet  long  and  5  inches  thick  ;  this  was  then  heated  in  the  chafery,  and 
under  the  tilt  hammer  drawn  out  to  a  "  bar,"  3  to  4  inches  wide,  and  half  inch  thick. 


65^  pv-rr- 


The  manufacture  up  to  this  point,  until  a  recent  period,  was  carried  on  by  the  iron 
masters,  and  the  iron  in  this  state  was  sold  under  the  name  of  "  tin  bars  "  to  the  plate 
makers.  The  average  price  for  these  bars,  from  1780  to  1810,  was  £21  per  ton.  The 
sheet  and  cold  rolls  were  then  in  use  nearly  .is  at  the  present  time 

In  1807,  Mr.  Watkin  George,  whose  position  had  been  established  as  one  of  the  first 
engineers  of  his  time,  by  the  erection  of  the  great  water  wheel  and  works  at  Cyfarthfa, 
removed  to  Pontypool,  and  undertook  the  remodelling  of  the  old  works  there.     He  clearly 


657 


656 


r  \  \ 


U L_L 


I    I  \ 


saw  that  the  secret  of  the  manufacture 
was  to  produce  the  largest  possible  quan- 
tity with  the  least  possible  machinery  and 
labor.  His  inventions,  to  this  end,  worked 
a  complete  change  in  the  trade.  His  plans 
were :  to  first  reduce  the  pig  iron  in  a 
finery  under  coke,  and  then  bring  tliis 
"  refiners'  metal "  (so  termed)  into  the 
charcoal  finery.  The  charcoal  finery  was 
))uilt  as  shown  mfigs.  654,  655,  and  656  ; 
fiij.  654  being  a  front  elevation,  fig.  655  a 
horizontal,  and  fig.  656  a  vertical  section. 
A  charge  of  3  cwt.  of  iron  was  used 
in  this,  and  as  it  became  malleable  it  was 
reduced  under  the  hammer  to  what  he 
termed  a  "  stamp :  "  this  was  a  piece  of 
iron  about  1  inch  thick,  and  of  any  shape 
horizontally.  It  was  next  broken  in 
pieces  of  a  convenient  size,  and  about  84 
lbs.  were  "  piled"  on  a  flat  piece  of  tilted 
iron,  with  a  handle  about  4  feet  long. 
This  rough  shovel,  or  holder,  was  called 


1054 


TIN  PLATES. 


the  "  portal,"  or  the  "  staff."     To  reheat  this  "  pile  "  in  the  chafery  would  be  a  work  of 
great  cost  and  difficulty,   and  the  brick  hollow  fire  (as  shown  in  fgs.  657,  658,  659,  660, 


661,  and  662  ;  fgs.  657  and  658  being  elevations,   and  fgs.  659,  660,  661,  and  662  sec- 
tions) was  invented.     This  is,  the  writer  believes,  one  of  the  inventions  which,  although 


•660 


in  work  during  the  past  fifty  years,  still  points  to  very  great  improvements  in  the  manufac- 
ture of  iron.  It  is  in  substance  the  plan  of  using  the  gases  produced  by  the  decomposition 
of  fuel  for  the  working  of  iron. 


The  charcoal  fnery  is  also  worked  by  the  use  of  the  gases  to  a  much  greater  extent 
than  is  generally  known.  The  workman  sends  his  blast  directly  into  the  mass  of  iron,  and 
the  charcoal  seems  to  be  simply  the  means  by  which  he  is  better  enabled  to  manipulate 
the  iron  in  the  finery,  and  keep  it  covered,  so  as  to  revive  the  oxidized  metal,  and  thus 
prevent  waste.  A  few  hours  spent  with  any  intelligent  workman  at  the  side  of  his  charcoal 
finery  would  show  the  wasteful  and  expensive  character  of  the  so-called  7icw  schemes  for  con- 


TIN  PLATES. 


1055 


662 


verting  cast  into  wrought  iron  by  the 
use  of  air  alone.  The  hite  belief  in 
these  schemes,  by  men  of  high  repute 
and  practical  knowledge  in  the  trade,  is 
a  direct  proof  of  the  deficiency  in 
knowledge  of  esact  science,  as  at  pres- 
ent applied  to  the  nianuf\xcture  of  iron. 

The  pile  was  now  placed  in  the  hol- 
low fire,  and  brought  to  a  soft  welding 
or  washing  heat — again  hammered  out 
to  "  slabs,"  6  inches  wide  and  three 
quarters  inch  thick  ;  these  were  re- 
heated, cut  up,  and  afterward  passed 
through  rolls,  reducing  them  to  "  bars" 
6  inches  by  half  inch.  These  were 
known  in  the  trade  as  "  hollow  fire 
iron"  or  "tin  bars."  The  result  of 
Mr.  Watkin  George's  improvements 
was  to  reduce  the  cost  and  double  the 
production  with  the  same  outlay  in 
machinery.  All  the  tin  plates  made 
at  this  time  had  the  great  defect  of  a 
rougii  and  smooth  side.  In  the  year 
1820,  Mr.  Win.  Daniell  (a  gentleman 
siill  living,  and  for  whose  invention 
the  trade  is  and  will  be  under  great 
obligation)  found  a  mode  to  remedy 
this  defect.  Himself  a  maker  of  tin 
bars  and  plates,  he  had  observed  that 
the  smooth  side  of  the  plate  was  al- 
w;iys  that  corresponding  to  the  flat 
part  of  the  "  portal,"  or  "  staff';  "  be 
at  once,  having  ascertained  this  cause, 
remedied  the  defect  by  hammering  out 
the  pile,  notching  it,  and  doubling  it 
over,  so  that  the  tilted  blade  of  the 
"  staff"  was  on  the  top  as  well  as  the 
bottom  of  the  pile.  Tliis  was  the  in- 
vention of  "  tops  and  bottoms,"  and 
the  writer  need  not  remind  practical 
men  of  the  immense  sums  made  by 
this  discovery  during  the  past  thirty- 
seven  years. 

Another  improvement  since  180T  is 
tlie  use  of  the  running-out  fire  :  it  is 
still  adopted  in  only  a  fow  works. 
Tiiis  is  represented  by  fyx.  003,  004, 
and  605.  fir;.  063  is  a  front  elevation  ; 
Jiff.  604  a  horizontal  section  ;  andfr/. 
665  a  vertical  section.  This  process 
saves  waste  of  heat  and  labor,  by  rim- 
ning  the  refined  metal  at  once  into 
the  charcufil  finery*. 


p 

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jpi 

I 

1056 


Tlis"  PLATES. 


The  "tin  bars"  before  referred  to,  6  inches  by  half  inch,  are  heated  and  run  through 
roll(?rs  until  they  form  a  sheet  of  sufficient  width  ;  this  sheet  is  then  doubled  and  passed 
through  the  rolls,  and  this  repeated  until  this  sheet  is  quadrupled, — the  laminae  are  then 
cut  to  size,  and  separated  as  before  described.  The  writer  asks  careful  attention  to  'the 
fact  that  the  last  part  of  the  rolling  is  done  when  the  iron  is  nearly  cold.  These  sheets 
are  next  annealed,  and  were  formerly  bent  separately  by  hand,  into  a  saddle,  forming  two 
sides  of  a  triangle,  thus  A ,  and  placed  in  a  reverberatory  furnace,  so  that  the  flame  should 
play  amongst  them,  and  heat  them  to  redness ;  they  were  then  plunged  into  a  bath  of 
muriatic  acid,  or  sulphuric  acid  and  water,  for  a  few  minutes,  taken  out,  and  drained  on 
the  floor,  and  again  heated  in  a  furnace ;  after  which,  a  scale  of  oxide  of  iron  separates 
from  the  plate  during  the  work  of  bending  them  again  straight,  on  a  cast-iron  block. 

The  plates  should  be  now  free  from  rust  or  scale,  and  are  then  passed  cold  through  the 
chilled  rolls ;  this  last  process  is  most  important,  as  the  ductility  and  the  strength  and  color 
of  the  tin  plate  depend  upon  this ;  at  this  point  bad  iron  will  crack  or  split,  and  any  want 
of  quality  in  the  iron,  or  skill  in  the  manufacture,  will  be  shown. 

A  great  improvement  in  the  process  of  annealing  was  made  in  1829  by  Mr.  Thomas 
Morgan :  the  plates  were  piled  on  a  stand,  and  covered  with  a  cast-iron  box,  now  termed  an 
"  annealing  pot ; "  in  this  they  were  exposed  to  a  dull  red  heat  in  a  reverberatory  furnace 

666 


for  24  hours.  This  annealing  pot  with  its  stand  is  represented  hj  fg.  666,  in  plan  and 
vertical  section. 

A  very  important  invention  in  the  manufacture  of  iron  for  tin  plates,  and  which  is  yet 
only  partially  carried  out,  was  made  by  Mr.  William  Daniell  in  184.5.  About  21  cwt.  of 
reflned  metal  is  placed  in  the  charcoal  finery ;  this  is  taken  out  in  one  lump,  put  under 
the  hammer  and  "nobbled,"  then  passed  at  once  through  the  balling  rolls,  and  reduced  to 
a  bar  6  inches  square  and  about  2  feet  6  inches  long.  This  bar  is  either  cut  or  sawed  off 
in  pieces  6  inches  long,  and  these  rolled  endways  to  give  a  bar  about  6  inches  wide,  2^ 
inches  thick,  and  12  inches  long,  and  in  this  state  the  inventor  calls  it  a  "billet."  This  is 
heated  in  a  small  baUing  furnace  and  rolled  down  to  a  bar  one  quarter  inch  thick  and  eleven 
inches  wide,  and  will  be  about  six  feet  long.  This  is  taken  at  once  to  the  tin-plate  mill, 
and  the  process  saves  great  expense  in  fuel  and  machinery. 

By  the  old  method  of  annealing,  a  box  of  tin  plates  required  about  13  lbs.  of  tin.  This 
is  now  done  with  about  9  lbs.  for  charcoal  and  8  lbs.  for  coke  plates. 

In  referring  to  tin  plates  the  standard  for  quotation  is  always  taken  as  1  C.  (Common, 
Xo.  1.)     This  is  a  box  containing  2'25  plates,  which  should  weigh  exactly  112  lbs. 

One  of  the  great  items  of  expense  in  the  manufacture  of  best  iron,  as  before  described, 
is  the  cost  of  charcoal  for  the  fineries.  This  limits  at  present  the  production  of  iron  made 
by  these  means ;  but  the  superior  quality  of  iron  made  in  the  charcoal  finery  is  always  ad- 
mitted. About  1850  the  attention  of  the  writer  was  directed  to  the  use  of  a  substifite  for 
charcoal  in  the  finery.  Careful  thought  and  experiment  led  him  to  the  conclusion  that  some 
coals  could  be  charred  in  such  a  way  as  to  produce  a  mechanical  structure  analogous  to 
charcoal,  and  at  the  same  time,  when  deprived  of  sulphur,  might  be  used  in  the  finery. 
These  experiments  resulted  in  the  manufacture  of  a  substance  the  writer  names  ^^  charred 
coaly  This  material  has  been  worked  at  several  of  the  principal  manufactories  in  South 
Wales,  and  declared  equal  in  every  respect  to  charcoal.  Some  tin  plates  made  by  this 
process  were  shown  at  the  Great  Exhibition  in  1851 ;  as  also  the  charred  coal  used  in  the 
finery.  (See  the  Juror^s  Reports,  dr.)  The  quality  of  the  plates  was  admitted  as  equal  to 
the  best  charcoal. 

The  preparation  of  the  '■^  charred  coaV  \s  very  simple.  The  coal  is  first  reduced  to 
small,  and  washed  by  any  of  the  ordinary  means :  it  is  then  spread  over  the  bottom  of  a 
reverberatory  furnace  to  a  depth  of  about  4  inches  :  the  bottom  of  the  furnace  is  first  raised 
to  a  red  heat.  When  the  small  coal  is  thrown  over  the  bottom  a  great  volume  of  gases  is 
given  off,  and  much  ebullition  takes  place  :  this  ends  in  the  production  of  a  light  spongy 
mass  which  is  turned  over  in  the  furnace,  and  drawn  in  about  one  hour  and  a  half.  To 
completely  clear  off  the  sulphur,  water  is  now  freely  sprinkled  over  the  mass  until  all  smell 
of  the  sulphuretted  hydrogen  gas  produced  ceases.  The  result  is  "  charred  coal."  The 
quantities  of  "  charred  coal "  hitherto  produced  have  been  made  on  the  floor  of  an  ordinary 


TIN  PLATES. 


1057 


coke  oven,  whilst  red  hot,  after  drawing  the  charge  of  coke.  The  following  analysis  of  the 
coal  from  which  this  "charred  coal"  is  made,  is  extracted  from  the  "Report  ou  the  Coals 
Suited  to  the  Steam  Navy,"  by  Sir  H.  De  la  Beche  and  Dr.  Playfair: — 

Abercarn  Coal. 

Carbon 81-26 

Hydrogen 6-31 

Nitrogen -  -11 

Oxygen        ...--..  9'96 

Sulphur 1-86 

Ash -         -  2-04 


102-20 

Some  points  of  great  practical  value  may  be  elicited  from  this  description  of  the  manu- 
facture of  iron  for  tin  plates.  The  stamp  iron  is  highly  crystalline,  and  falls  to  pieces  under 
the  hammer  unless  cautiously  handled.  The  pile  itself,  after  heating,  is  also  crystalline 
and  brittle ;  but  after  passing  through  the  rolls  it  becomes  less  crystalline.  When  reduced 
to  a  sheet  it  is  still  less  crystalline  and  more  ductile  ;  but  after  passing  the  cold  rolls  all  the 
crystalline  character  is  apparently  destroyed,  and  it  becomes  a  homogeneous  mass,  and  very 
ductile,  hard,  and  tough.  The  hammering  and  rolling  appear  to  alter  the  structure  of  the 
iron,  and,  instead  of  allowing  the  atoms  to  arrange  themselves  in  crystals,  to  bring  them  into  a 
homogeneous  or  amorphous  mass,  which  is  then  held  together  by  the  law  of  cohesion,  and  is 
more  dense  and  closer  than  when  crystallized.  In  practice  this  principle  is  constantly 
used.     Every  smith  knows  the  practicil  result  of  what  is  termed  "  hammer  hardening." 

Tin  coating  of  iron  and  zi/ic,  by  Mr.  Morries  Stirling's  patent  process.  For  this  pur- 
pose the  sheet,  plate,  or  other  form  of  iron,  previously  coated  with  zinc,  cither  by  dipping 
or  by  depositing  from  solutions  of  zinc,  is  taken,  and  after  cleaning  the  surface  by  washing 
in  acid  or  otherwise,  so  as  to  remove  any  oxide  or  foreign  matter  which  would  interfere  with 
the  perfect  and  equal  adhesion  of  the  more  fusible  metal  or  alloy  with  which  it  is  to  be 
coated,  it  is  dipped  into  melted  tin,  or  any  suitable  alloy  thereof,  in  a  perfectly  fluid  state, 
the  surface  of  which  is  covered  with  any  suitable  material,  such  as  fatty  or  oily  matters,  or 
the  chloride  of  tin,  so  as  to  keep  the  surface  of  the  metal  free  from  oxidation ;  and  such 
dipping  is  to  be  conclucted  in  a  like  manner  to  the  process  of  making  tin  plate  or  of  coating 
iron  with  zinc.  When  a  fine  surface  is  required,  the  plates  or  sheets  of  iron  coated  with 
zinc  may  be  passed  between  polished  rolls  (as  already  described)  before  and  after,  or  either 
before  or  after  they  are  coated  with  tin  or  other  alloy  thereof.  It  is  preferred  in  all  cases 
to  use  for  tlie  coating  pure  tin  of  the  description  known  as  grain  tin. 

Another  part  of  the  invention  consists  in  covering  either  (wholly  or  in  part)  zinc  and  its 
alloys  with  tin,  and  such  of  its  alloys  as  are  sufficiently  fusible.  To  effect  this,  the  following 
is  the  process  adopted : — A  sheet  or  plate  of  zinc  (by  preference  such  as  has  been  previous- 
ly rolled,  both  on  account  of  its  ductility  and  smoothness)  is  taken,  and  after  cleaning,  its 
surface  by  hydrochloric  or  other  acid,  or  otherwise,  it  is  dried,  and  then  dipped  or  passed 
in  any  convenient  manner  through  the  melted  tin,  or  fusible  allqy  of  tin.  It  is  found 
desirable  to  heat  the  zinc,  as  nearly  as  may  be,  to  the  temperature  of  the  melted  metal, 
previous  to  dipping  it,  and  to  conduct  the  dipping,  or  passing  through,  as  rapidly  as  is  con- 
sistent with  thorough  coating  of  the  zinc,  to  prevent  as  much  as  possible  the  zinc  becoming 
alloyed  with  the  tin.  It  is  recommended  also  that  the  tin  or  alloy  of  tin  should  not  be  heat- 
ed to  a  higher  temperature  than  is  necessary  for  its  proper  fluidity.  The  metal  thus  coated, 
if  in  the  form  of  sheet,  plate,  or  cake,  can  then  be  rolled  down  to  the  required  thickness ; 
and  should  the  coating  of  tin  or  alloy  be  found  insufficient  or  imperfect,  the  dipping  is  to 
be  repeated  as  above  deseril)ed,  and  the  rolling  also,  if  desired,  either  for  smoothing  the 
surface  or  further  reducing  the  thickness. 

Another  part  of  the  invention  consists  in  coating  lead  or  its  alloys  with  tin  or  alloys 
thereof.  The  process  is  to  be  conducted  as  before  described  for  the  coating  of  zinc,  and  the 
surface  of  lead  is  to  be  perfectly  clean.  The  lead  may,  like  the  zinc,  be  dipped  more  than 
once,  either  before  or  after  being  reduced  in  thickness  by  rolling. 

Lead  and  its  alloys  may  also  be  coated  with  tin  or  its  alloys  of  greater  fusibility  than  the 
metal  to  be  coated,  as  follows: — The  cake,  or  other  form  to  be  coated,  is  to  be  placed  as 
soon  after  casting  as  may  be  in  an  iron,  gun  metal,  or  other  suitable  mould ;  or,  if  this  can- 
not be  conveniently  done,  the  surfaces  are  to  be  cleansed  and  prepared  for  the  reception  of 
the  coating  metal,  either  ])y  previously  tinning  the  surfiice,  or  by  applying  other  suitable 
material  to  facilitate  the  union,  as  heretofore  practised.  At  one  end  of  the  mould  are  to  be 
attached  chambers,  of  more  than  sufficient  capacity  to  contain  the  quantity  of  metal  to  be 
used  for  coating,  which  may  with  advantage  form  an  integral  part  of  the  mould,  or  such 
chamber  may  surround  the  mould,  anil  by  one  or  more  sluices  or  valves  in  such  chamber 
or  chambers,  th;;  melted  metal  is  to  ))e  allowed  to  run  on  to  the  surface  of  the  metal  to  be 
coated,  when  the  metal  is  to  be  coated  on  one  side  only.  When  it  is  intended  to  coat  the 
metal  on  both  sides,  the  vertical  position  will  be  found  convenient,  and  the  coating  metal  is 
Vol.  III.— (17 


1058 


TUBES. 


to  be  poured  into  a  chamber  or  chambers  attached  to  the  mould,  and  to  be  introduced  into 
the  lower  part  of  the  mould  by  opening  a  sluice  or  valve,  sufficient  space  being  left  on  each 
side  of  the  cake  or  other  form  to  allow  of  the  coating  being  of  the  required  thickness ;  the 
sluice  or  valve  should  be  of  nearly  the  width  or  length  of  the  cake  or  other  form,  and  the 
melted  metal  should  be  allowed  to  flow  into  the  bottom  of  the  mould.  The  surface  of  the 
plate  or  cake  ought  to  be  smooth  and  true,  and  the  mould,  if  horizontal,  to  be  perfectly  so, 
and  if  upright,  quite  perpendicular,  so  as  to  insure  in  either  case  an  equal  footing.  The 
surface  of  the  lead  should  also  be  clean,  and  it  will  be  found  advantageous  to  raise  its  tem- 
perature to  a  point  somewhat  approaching  the  melting  point  of  tin  or  of  the  alloy  employed 
for  coating,  as  by  this  means  the  union  of  the  two  metals  is  facilitated.  It  is  recommended 
also,  that  a  somewhat  larger  quantity  of  the  tin  or  alloy  than  is  necessary  for  the  coating 
of  the  lead  or  other  metal,  or  alloy,  should  be  employed,  and  that  when  the  requisite  thick- 
ness of  coating  has  been  given,  the  flow  of  the  coating  metal  be  stopped,  as  by  this  means 
the  impurities  on  the  surface  of  the  tin  will  be  prevented  passing  through  the  opening  on 
to  the  surface  of  the  cake  :  the  chamber  or  chambers  should  be  kept  at  such  temperature 
as  to  insure  the  proper  fluidity  of  the  coating  metal.  Zinc  and  its  alloys  may  in  like 
manner  be  coated  with  tin  and  its  alloys,  by  employing  a  like  apparatus  to  that  just  describ- 
ed for  coating  lead  and  its  alloys,  and  it  constitutes  a  part  of  this  invention  thus  to  coat 
zinc.  The  coating  of  zinc  with  tin,  however,  is  not  claimed,  that  having  been  done  by 
pouring  on  tin. 

TUBES.  The  manufacture  of  iron  tubes  for  gas,  water,  and  other  purposes  has  become 
one  of  extreme  importance.  Mr.  Russell  of  Wednesbury  patented  a  process  which  has  been 
carried  out  on  a  very  large  scale.  In  this  process  plate  iron,  previously  rolled  to  a  proper 
thickness,  is  cut  into  such  strips  or  lengths  as  may  be  desirable,  and  in  breadth  correspond- 
ing with  the  width  of  the  tube  intended  to  be  formed.  The  sides  of  the  metal  are  then  bent 
up  with  swages  in  the  usual  way,  so  as  to  bring  the  two  edges  as  close  as  possible  together. 

^  The  iron  thus  bent  is  then  placed  in  an 

air  or  blast  furnace,  and  brought  to  a 
welding  heat,  in  which  state  it  is  with- 
drawn and  placed  under  the  hammer. 
Fig.  667,  a,  is  the  anvil  having  a  block 
or  bolster,  with  a  groove  suited  to  and 
corresponding  with  a  similar  groove,  b,  in 
the  face  of  the  block,  c  is  a  wheel  with 
projecting  knobs,  which,  striking  in  suc- 
cession upon  the  iron-shod  end  of  the 
hammer  shaft,  causes  it  to  strike  rapidly 
on  the  tube.  In  this  process  the  tube  is 
repeatedly  heated  and  hammered,  until 
the  welding  is  complete  from  end  to  end. 
A  mandril  may  be  inserted  or  not  dur- 
ing this  operation.  When  the  edges  of 
iron  have  been  thus  thoroughly  united, 
the  tube  is  again  heated  in  a  furnace, 
and  then  passed  through  a  pair  of 
grooved  rollers  similar  to  those  used  in 
the  production  of  rods.  Jig.  668.  Sup- 
pose a  tube,  D,  to  be  passing  through 
these  rollers,  of  which  j?_qr.  669  represents  a  cross  section,  immediately  upon  its  being  de- 
livered from  the  groove  it  receives  an  egg-shape  core  of  metal  fixed  upon  the  extremity 
of  the  rod  e,  over  which  the  tube  sliding  on  its  progress,  the  inside  and  outside  are  per- 
fected together.  Mr.  Cort  patented  a  similar  process  for  the  manufacture  of  gun  barrels. 
TUFA.     A  volcanic  product.     See  Mortar,  Hydraulic,  vol.  ii. 

TUXGSTEX.  (Tunr/sienc,  Ft.  ;  Wolframiian,  Germ.)  Symbol,  Ts  or  W.  Its  name 
is  derived  from  the  principal  mineral  from  which  it  is  obtainable.  Tungsten,  Swedish, 
fnnrr,  heavy,  sten,  stone,  or  Wolfram,  German.  This  metal  was  discovered  by  the  brothers 
Do  Luyart,  about  1784,  shortly  after  the  discovery  of  tungstic  acid  by  Scheele,  from  whom 
it  is  sometimes  called  Scheelium.  It  is  never  found  in  the  native  state,  but  is  produced  by 
a  variety  of  processes.  First,  and  most  easily,  by  mixing  the  dried  and  finely-powdered 
tungstate  or  bitungstate  of  soda  with  finely-divided  charcoal,  such  as  i  lampblack,  placing 
tlie  mixture  in  a  crucible  lined  with  charcoal,  covering  it  with  charcoal  in  powder,  and  then 
exposing  the  whole  to  a  steady  red  heat  for  two  or  three  hours.  On  removal  of  the  cru- 
cible and  cooling  it,  a  porous  mass  is  found,  from  which  the  soda  is  removed  by  solution  in 
water,  and  the  unconsumed  carbon  is  separated  by  washing  it  off,  the  metal  being  left  as  a 
bright,  glistening,  blackish-gray  metallic  powder.  It  may  also  be  obtained  by  treating 
tungstic  acid  in  a  similar  manner,  or  by  exposing  the  acid  at  a  bright  red  heat,  in  an  iron 
or  glass  tube,  to  a  current  of  hydrogen  gas.     Tungsten  is  one  of  the  heaviest  metals  known. 


TUNGSTEN". 


1059 


its  specific  gravity  being  17'22  to  17"6.  It  requires  such  a  very  high  temperature  for 
fusion  thit  it  has  never  yet  been  obtained  in  mass;  more  commonly  as  a  fine  powder,  but 
sometimes  in  small  grains.  It  is  not  magnetic.  It  is  very  hard  and  brittle.  Alone  it  has 
not  been  rendered  available  for  any  useful  purjiose,  but  it  has  lately  been  employed  for  the 
manufacture  of  certain  alloys.  Tungsten  is  comparatively  a  rare  substance,  and  is  remark- 
able for  the  very  limited  extent  to  which  in  nature  it  is  found  to  have  been  mineralized  by 
combination  with  other  substances.  In  none  of  these  does  it  exist  as  a  salifiable  base,  but 
as  an  acid,  as  in  wolfram,  Scheelite,  yttrolantalite,  and  the  tungstatc  of  lead. 

The  most  common  ore  of  this  metal  is  wolfram,  known  also  to  the  CornLsh  miner  as  cal 
or  callen,  and  gossan.  It  is  most  commonly  found  associated  with  tin  ores,  which  contain 
besides  the  black  oxide  of  tin  or  cassiterite,  the  metallic  minerals,  arsenical  iron,  copper, 
lead,  and  zinc  sulphides ;  but  its  peculiarly  characteristic  associate  is  the  metal  molybde- 
imm,  for  the  most  pait  mineralized  as  a  sulphide.  This  metal  is  remarkable  in  connection 
with  tungsten  as  producing  isoiieric  compounds,  and  as  having  both  its  equivalent  and  its 
specific  gravity  equal  to  about  one  half  that  of  tungsten,  they  being  respectively  as  fol- 
lows:— equivalents,  Ts,  9'),  Mo,  48;  sp.  gr.  Ts,  ltV22,  Mo,  8-615. 

Amongst  miners  wolfram  has  the  reputation  of  being  an  abundant  mineral,  but  on  close 
inquiry  it  is  found  to  be  comparatively  rare,  scliorl,  specular,  and  other  iron  ores,  and 
gossan  being  commonly  mistaken  for  it.  From  its  association  with  tin  ores,  it  has  been 
until  lately  the  source  of  great  loss  to  the  miner,  as  it  was  found  quite  impossible  to  sepa- 
rate it  even  to  a  moderate  extent  from  the  ore  in  consequence  of  its  specific  gravity,  7"!  to 
7'4,  being  so  near  to  that  of  black  tin,  6"3  to  7"0. 

Pryce,  in  his  Mineralogia  Cornubiensis,  1778,  says:  "After  the  tin  is  separated  from  all 
other  impurities  by  repeated  ablutions,  there  remains  a  quantity  of  this  mineral  sul)stince, 
(gal,)  which  being  of  equal  gravity  cannot  be  separated  from  the  tin  ore  by  water,  therefore 
it  impoverishes  the  metal  and  reduces  its  value  down  to  8  or  0  parts  of  metal  for  twenty 
of  mineral,  which  without  its  brood,  so  called,  miglit  fetch  twelve  for  twenty."  This  de- 
scription of  tin  ores  containing  wolfram  was  still  applicable  until  a  very  recent  period,  when 
a  new  process  was  invented  by  Mr.  Robert  Oxland,  of  Plymouth,  and  by  him  successfully 
introduced  at  the  Drake  AValls  Tin  Mine,  at  Gunnis  Lake,  on  tlie  banks  of  the  Tamar, 
where  it  has  been  continued  in  operation  ever  since.  At  this  mine,  although  the  tin  ore 
raised  was  of  excellent  quality,  in  spite  of  all  that  could  be  done  by  the  old  processes,  it 
was  left  associated  with  so  much  wolfram  that  the  ore  fetched  the  lowest  price  of  any  mine 
in  Cornwall. 

At  the  time  of  the  introduction  of  the  process  the  greater  portion  of  the  ore  was  sold  for 
£42  per  ton.  The  improvement  efTected  by  it  was  so  great  that  the  same  sort  of  ore  sold  for 
£56  per  ton.     The  Drake  Walls  ores  are  now  known  as  the  best  of  the  mine  ores  in  Cornwall. 

The  process  is  a  neat  illustration  of  the  advantages  obtainable  by  the  careful  direct 
application  of  scientific  principles,  guided  by  practical  experience,  to  the  improvement  of 
the  results  obtainable  by  mining  operations. 

The  process  consists  in  taking  tin  ores  mixed  with  wolfram,  dressed  as  completely  as 
possible  by  the  old  process,  and  having  ascertained  liy  analysis  tlie  quantity  of  wolfram  con- 
tained therein,  then  mixing  therewith  such  a  quantity  of  soda  ash  of  known  value  as  shall 
afford  an  equivalent  of  soda  for  combination  with  the  tungstic  acid  of  the  wolfram,  which 
is  the  tungstate  of  iron  and  manganese;  the  o))ject  of  the  process  being  by  calcination  to 
convert  the  insoluble  tuugstate  of  iron  and  manganese  into  the  soluble  tungstate  of  soda, 
leaving  the  oxides  of  iron  and  manganese  in  a  very  finely-divided  state  and  of  low  specific 
gravities,  so  that  they  can  be  easily  washed  off"  with  water. 

The  mixture,  in  cliarges  of  five  to  ten  cwt.,  is  roasted  in  a  reverberatory  furnace  on  a 
cast-iron  bed    of   the    construction 

siiown  in  X'/s'-  070  and  671.     The  670 

use  of  the  cast-iron  bed  is  attended 
witii  considerable  economy  in  the 
consumption  of  fuel,  and  it  is  ad- 
mirably well  adapted  for  the  calcina- 
tion of  the  raw  ores,  for  the  evolu- 
tion of  the  sulphur  and  arsenic  con- 
tained in  them  ;  but  it  is  especially 
necessary  instead  of  fire  brick  or 
tile,  to  avoid  the  loss  which  would 
accrue  from  the  reaction  of  the  soda 
ash  on  the  silica  of  the  brick,  and  the 
formationofsodasilicateof  tin  which 
would  consequently  take  place.  The 
mixture  is  introduced  to  the  bed 
through  a  hole  in  the  crown  of  the 
fiu-nace ;  from  a  side  door  it  is 
eciually  distributed   over   the    bed. 


|''//#^# 


1060 


TURBINE. 


and  from  time  to  time  it  is  turned 
over  by  the  furnace  man  until  the 
whole  mass  is  of  a  dull  red  heat, 
emitting  a  slight  hissing  sound,  and 
in  an  incipient  pasty  condition.  In 
successive  quantities  the  charge  is 
then  drawn  through  a  hole  in  the 
bed  of  the  furnace  into  the  wrinkle 
or  arch  beneath,  whence  it  is  re- 
moved to  cisterns,  in  which  it  is 
lixiviated  with  water,  and  the  tungs- 
tate  of  soda  is  drawn  off  in  solu- 
tion. The  residuary  mass  left  in 
the  cisterns, — the  whole  of  the  solu- 
ble matter  having  been  washed  out, 
— is  removed  to  the  burning-house 
floors,  and  is  there  dressed  over 
again  in  the  usual  manner,  the  final 
product  of  the  operations  being  very 
nearly  pure  black  oxide  of  tin.  The  liquid  obtained  is  either  evaporated  sufficiently  for 
crystallization  when  set  aside  to  cool,  or  is  at  once  dried  down  to  powder.  The  crystals  of 
tungstate  of  soda  thus  obtained  are  colorless,  translucent,  of  a  beautiful  pearly  lustre,  having 
the  form  of  rhombic  prisms  or  of  four-sided  laminae.  The  composition  of  the  crystallized 
and  of  the  anhydrous  tungstate  of  soda  is  as  follows : — 

Anhydrous.  Crystalline. 

20-63  18-44 


Soda  -  .  - 
Tungstic  acid 
Water  - 


79-37 
•00 


70-92 
10-64 


100-00 


100-00 


It  has  been  proposed  to  use  this  substance  as  a  mordant  for  dying  purposes,  as  a  source 
of  supply  of  metallic  tungsten  for  the  manufacture  of  alloys,  for  the  manufacture  of  the 
tungstates  of  lime,  barytes,  and  of  lead  to  be  used  as  pigments ;  and  still  more  recently  it 
has  been  found  to  be  valuable,  and  preferable  to  any  other  substance,  for  rendering  frabrics 
not  inflammable,  so  as  to  prevent  the  terrible  accidents  constantly  occurring  from  the  burn- 
ing of  ladies'  dresses.  For  this  purpose  a  patent  has  lately  been  obtained  by  Messrs.  Vers- 
mann  and  Oppenheim. 

For  the  manufacture  of  metallic  alloys  a  patent  has  been  obtained  by  Mr.  R.  Oxland, 
as  a  communication  from  Messrs.  Jacob  and  Koeller.  Steel  of  very  superior  quality,  man- 
ufactured under  this  patent,  is  now  coming  extensively  into  use  in  Germany.  It  is  prepared 
by  simply  melting  with  cast  steel,  or  even  with  iron  only,  either  metallic  tungsten,  or  prefer- 
ably, what  has  been  termed  the  native  alloy  of  tungsten,  in  the  proportion  of  two  to  five 
per  cent.  The  steel  obtained  works  exceedingly  well  under  the  hammer.  It  is  very  hard 
and  fine  grained,  and  for  tenacity  and  density  is  superior  to  any  other  steel  made.  The  na- 
tive alloy  is  obtained  by  exposing  to  strong  htat  in  a  charcoal-lined  crucible  a  mixture  of 
clean  powdered  wolfram  with  fine  carbonaceous  matter.  A  black,  steel-gray  metallic  spongy 
mass  is  obtained  resembling  metallic  tungsten.  The  composition  of  the  alloy  is  shown  in 
the  following  statement  of  the  composition  of  wolfram : — 

Tungstic  acid.  Oxide  of  Iron.  Oxide  of  manganese. 

Tungsten     76-25  Iron  17-75  Manganese  6-00  =   100 

Oxygen       19-06  Oxygen       5-07  Oxygen       1-71  =     25-84 


125-84 
The  tungstate  of  soda  is  used  in  dyeing;  metallic  tungsten,  or  native  alloy,  is  also  used 
for  the  manufacture  of  packfong  or  Britannia  metal,  by  alloying  with  copper  and  tin. 

By  these  useful  applications  this  metal  has  already  become  a  desideratum,  which  only  a 
few  years  since  was  regarded  as  one  of  the  most  deleterious  associates  of  tin  ores,  and  the 
only  one  that  was  perfectly  unmanageable. — R.  0. 

TURBINE.  Although  the  horizontal  water  wheel  has  been  known  and  employed 
under  various  forms  from  the  highest  antiquity,  and  has  latterly  been  improved  by  Fourncy- 
ron,  Fontaine,  Jouval,  and  others,  so  as  to  rank  among  the  most  perfect  of  hydraulic  motors, 
it  has  only  recently  been  applied  to  mining  uses,  (pumping,  loading,  &c.,)  and  where  so 
employed  its  success  can  scarcely  be  said  to  be  yet  decided.  The  failures  may  be  attributed 
to  the  following  causes.  First:  The  plan  of  causing  the  water  to  flow  simultaneously 
through  all  the  buckets,  necessitates  the  use  of  wheels  of  small  dimensions,  making  a  very 
great  number  of  revolutions  per  minute,  and  thus  requiring  a  considerable  train  of  inter- 
mediate gear  to  reduce  the  speed  to  the  working  rate.     Second:  The  complex  nature  of 


TURBINE. 


1001 


the  ring  sluices  employed  between  the  guide  curves  and  the  mouths  of  the  bucket,  renders 
them  uncertain  in  action,  and  from  their  small  dimensions  liable  to  be  easily  choked  by  any 
mechanical  impurities  in  the  water;  and  lastly,  the  lubrication  of  the  foot  spindle  of  the 
vertical  wheel,  revolving  at  very  great  velocity,  is  attended  with  considerable  difficulty  and 
incouvenience,  especially  where  the  engine  room  is  at  a  considerable  distance  below  the 
surface  of  the  earth,  and  it  is  requisite,  as  in  the  case  of  pumping  wheels,  to  keep  the 
machinery  in  action  continuously  for  long  periods  of  time.  The  form  of  wheel  of  which 
a  notice  is  here  appended,  was  introduced  into  the  Saxon  mines  about  the  year  1849  by 
Herr  Schwamkrug,  inspector  of  machinery  at  the  Royal  Mines  and  Smelting  Works  at  Frey- 
berg,  and  since  that  time  several  have  been  introduced  for  pumping,  winding,  driving 
stampheads,  &c.  The  example  selected  for  illustration  was  built  to  take  the  place  of  two 
overshot  water-wheels,  employed  in  pumping  water  at  the  mine  "  Churprinz  Friedrich  Au- 
gust ; "  it  differs  from  the  usual  form  of  turbine  in  having  the  wheel  placW  vertically,  and 
in  having  the  water  supplied  through  a  small  number  of  guide  curves  near  the  lowest  part. 
In  this  latter  respect  it  resembles  the  tangential  turbine  of  General  Poncelet,  with  this  dif- 
ference, that  the  water  flows  from  the  inner  to  the  outer  circumference,  instead  of  the 
reverse  way,  as  is  the  case  in  Poncelet's  wheel.  The  construction  of  the  wheel  is  as  follows : 
a^fig.  672,  is  the  tubular  axle  of  cast  iron  which  carries  the  seating  for  the  arms  s,  which  is 


672 


similar  to  that  usually  used  for  large  water  wheels ;  to  the 
ends  of  the  arms  is  attached  the  wheel  ?o,  which  is  formed 
of  two  brags  or  shroudings  of  sheet  iron,  each  1"  inches 
deep,  measured  radially,  and  of  a  total  height  of  10  feet  2 
inches ;  these  two  rings  are  maintained  at  a  distance  of  0 
inches  apart,  by  means  of  44  sheet-iron  buckets  of  the 
form  shown  in  the  smaller  detailed  figure,  ficj.  OT^i ;  the 
driving  water  is  admitted  thiough  the  pressure  pipe  y), 
in  which  is  placed  the  admission  throttle  <,  and  turned  tlirough  a  pipe  of  rectangular  sec- 
tion (shown  in  the  smaller  figure)  into  the  sluice  box  .s-,  wliich  contains  tiic  two  guide  curves 
V,  v',  wliich  arc  movable  about  the  centres  c,  <■',  ))y  means  of  the  levers  /,  l\  l>y  means  of 
these  guide  curves  when  fully  oi)encd,  as  shown  in  tiie  figure  ;  the  water  is  admitted  into 
the  buckets  in  two  parallel  streams  of  jets  of  5j-  inches  in  breadth,  and  I'/iu  inches  in 
thickness;  the  power  is  transmitted  from  tlie  axle  of  the  wliee!  by  a  pinion  with  28  teeth, 
wliich  draws  the  large  toothed  wheel  x,  which  acts  on  a  third  shaft  carrying  the  pump 


1062  TUKKEY  RED. 

cranks.  The  wheel  is  constructed  to  work  under  a  head  of  147  feet,  and  makes  about  130 
revolutions  per  minute,  with  a  maximum  quantity  of  550  cubic  feet  of  water,  equal  to 
nearly  175  horse  power.  A  series  of  dynamomefrieal  experiments  on  a  wheel  of  similar 
construction  of  7  feet  9  inches  in  diameter,  with  a  discharge  varying  from  89  to  134  cubic 
feet,  with  a  head  of  103  feet,  gave  an  available  duty  of  from  58  to  79  per  cent.,  the  number 
of  revolutions  varying  from  112  to  148  per  minute. 

In  conclusion  it  may  be  remarked  that  the  vertical  turbine  may  be  employed  with 
advantage  where  the  available  fall  of  water  is  too  great  to  be  employed  on  a  single  overshot 
water-wlieel ;  and  although  a  less  perfect  machine  than  the  water-pressure  engine,  it  is  of 
simpler  construction,  and  may  be  preferred  where,  from  the  hardness  or  yielding  nature  of 
tlie  rock,  it  becomes  ditlicult  to  construct  large  machine  rooms  or  wheel  pits  underground. 
In  practice  it  is  found  necessary  to  surround  the  wheel  with  a  casing  of  wood,  in  order  to 
prevent  the  affiif^nt  water  being  projected  to  a  distance  from  centrifugal  action. 

TUKKEY  RED  is  the  name  given  to  one  of  the  most  beautiful  and  durable  of  known 
dyes.  The  art  of  dyeing  cotton  with  this  color  seems  to  have  originated  in  India.  In  his 
Philoaopliy  of  Permanent  Colors^  Bancroft  has  given  a  detailed  account  of  the  process  as 
practised  in  that  country,  and  this  process  will  be  found  to  agree  in  all  essential  particulars 
with  that  pursued  by  the  Turkey-red  dyers  of  Europe,  except  that  in  India  the  chaya  root 
is  employeil  as  the  dyeing  material  in  the  place  of  madder.  In  the  middle  ages  the  art  was 
practised  in  various  parts  of  Turkey  and  Gicece,  especially  in  the  neighborhood  of  Adria- 
nople,  and  hence  this  color  is  olten  called  Adrimwple  red.  Even  as  late  as  the  end  of  the  last 
century  the  manufacture  of  Turkey-red  yarn  seems  to  have  been  extensively  cariied  on  at 
Ambelakia  and  other  places  in  the  neighborhood  of  Larissa.  An  interesting  account  of  the 
manufactuics  and  trade  of  this  then  flourishing  district,  by  Felix,  will  Vje  found  in  the  An- 
iialex  de  Cfiimie,  t.  xxi.  1799.  About  the  middle  of  the  last  century  the  art  of  Turkey-red  dye- 
ing was  introduced  into  France  by  means  of  dyers  brought  over  from  Greece.  The  French 
were  also  the  first  to  dye  pieces  with  this  color,  the  art  having  previously  been  applied  merely 
to  the  dyeing  of  yarn.  The  first  establishments  for  dyeing  this  color  in  (ireat  Britain  were 
founded  and  conducted  by  Frenchmen.  At  the  present  day  Turkey-red  dyeing  is  carried 
on  in  various  parts  of  France  and  Switzerland,  at  Elberfeld  in  Germany,  in  Lancashire,  and 
at  Glasgow. 

Turkey-red  dyeing  is  essentially  distinguished  from  other  dyeing  processes  by  the  appli- 
cation previous  to  dyeing  of  a  peculiar  preparation  consisting  of  fatty  matter  combined  with 
other  materials.  Without  the  use  of  oil  or  some  fatty  matter  it  would  be  impossible  to  pro- 
duce this  color,  of  which  indeed  it  seems  to  form  an  essential  constituent.  If  the  color  of 
a  piece  of  Turkey-red  cloth  be  examined,  it  will  lie  found  to  consist  of  red  coloring  matter 
and  fat  acid,  combined  with  alumina  and  a  little  lime.  The  coloring  n:atter  thus  obtained 
is  so  little  contaminated  with  impurities  as  to  appear  on  evaporating  its  alcoholic  solution 
in  yellowish-red  crystalline  needles.  What  part  the  fat  acid  plays,  whether  it  merely  serves 
to  give  to  the  compound  of  coloring  matter  and  alumina  the  power  of  resisting  the  action 
of  the  powerful  agents  used  after  the  operation  of  dyeing,  or  whether  it  also  modifies  and 
imparts  additional  lustre  to  the  color  itself,  is  quite  unknown.  The  formation  of  this  triple 
compoiind  of  coloring  matter,  fiit  acid,  and  alumina,  seems  at  all  events  to  be  the  final  result 
which  is  attained.  Nevertheless,  this  apparently  simple  result  can  only  be  anived  at  by 
means  of  a  long  and  complicated  piocess,  each  step  of  which  seems  to  be  essential  for  its 
final  success.  The  details  of  the  process  vary  considerably  both  in  theii-  nature  and  number, 
in  different  countries  and  different  dyeing  establishments.  They  may  however  be  described 
in  general  terms  as  follows : — 

The  goods,  after  being  passed  through  a  soap  1  ath  or  weak  alkaline  lye,  are  oiled.  For 
this  purpose  a  mere  impregnation  with  oil  would  not  be  sufficient.  The  oil  must  be  mixed 
with  a  solution  of  carbonate  of  potash  or  soda,  to  which  there  is  often  added  a  quantity  of 
sheep  or  cow  dung,  the  ingredients  being  well  mingled,  so  as  to  foim  a  n.ilky  liquid  or 
emulsion.  Olive  or  Gallipoli  oil  is  the  kind  generally  used,  and  an  impure,  mucilaginous 
oil  is  preferred  to  one  of  a  finer  quality.  Drying  oils  are  not  adapted  for  th.e  i)urpc*e.  In 
this  li(|uid  the  goods  are  steeped  for  a  short  time,  so  as  to  become  thoroughly  impregnated 
with  it.  In  the  case  of  pieces  the  liquid  is  generally  applied  by  means  of  a  padding  machine. 
After  being  taken  out  of  this  lifpiid  the  goods  are  often  left  to  lie  for  some  days  in  heaps, 
and  if  the  weather  is  fine,  they  are  then  exposed  on  the  grass  to  the  action  of  the  air ;  other- 
wise, they  must  be  hung  up  in  a  hot  stove.  Tliis  process  of  steeping  and  exposing  to  the 
air  is  repented  a  number  of^  times,  until  the  fabric  is  thorougly  impregnated  with  fatty  mat- 
ter. Duiing  tliis  part  of  the  process  there  can  be  no  doubt  that  the  oil  undergoes  a  partial 
decomposition  and  oxidation,  so  as  to  become  capable  of  uniting,  on  the  one  hand,  with  the 
vegetable  fibre,  and,  on  the  other  hand,  with  the  coloring  matter,  with  which  it  is  subsequently 
brought  into  contact.  The  dung,  by  inducing  a  state  of  fermentation  among  the  ingredients, 
probably  promotes  the  decomposition  of  the  oil  into  f^itty  acid  and  glycerine,  and  the  alkali 
serves  to  convey  the  fattv  acid  into  every  part  of  the  fabric,  and  to  assist  m  its  oxidation  on 
exposure  to  the  air.     The  process  of  oxidation  wliich  takes  place  is  sometimes  so  active  as  to 


TURKEY  RED. 


1063 


produce  spontaneous  combustion  of  the  goods  in  the  stove.  It  might  be  supposed  that  by 
previously  saponifying  the  oil,  impregnating  the  goods  with  the  soap,  and,  after  suflicient 
exposure,  decomposing  the  latter  by  means  of  an  acid,  the  same  object  might  be  more  easily 
attained  than  by  the  long  process  usually  employed.  This  i.-^,  however,  not  the  case,  which 
proves  that  we  are  still  ignorant  of  the  e.\act  chemical  nature  of  the  change  which  takes 
place  during  the  oiling  process.  The  supposition  formerly  entertained,  that  the  eflect  of  the 
oiling  consi-sted  in  a  so-called  aniniallzation  of  the  vegetable  fibre,  is  quite  untenable.  In 
some  establishments,  the  goods,  after  being  oiled  and  stoved,  are  passed  through  a  bath  of 
very  dilute  nitric  acid,  and  then  exposed  to  the  air  belbre  being  oiled  again,  the  process 
being  repeated  after  every  oiling.  The  nitric  acid  is  supposed  to  contriljute  to  the  oxidation 
of  the  oil.  Several  years  ago  a  patent  was  taken  out  by  .Messrs.  Mercer  and  Greenwood  for 
preparing  the  oil,  previous  to  its  being  applied  to  the  cotton,  by  treating  it  with  sulphuric 
acid,  and  then  with  chloride  of  soda,  but  tiieir  invention,  though  apparently  of  some  import- 
ance, has  not  generally  been  adopted  by  Turkey-red  dyers. 

After  being  oiled,  the  goods  are  steeped  for  some  hours  in  a  weak  tepid  solution  of  car- 
bonate of  potash  or  soda.  This  operation,  which  is  called  by  the  French  dcgraissage,  serves 
to  remove  the  excess  of  fatty  acid,  or  that  portion  which  has  not  thoroughly  combined  with 
the  vegetable  fibre.  The  liquid  thus  obtained  is  carefully  preserved  for  the  purpose  of 
being  mixed  with  the  liquid  used  for  the  oiling  of  fresh  goods,  the  quality  of  which  it  serves 
to  improve. 

To  this  operation  succeeds  that  of  galling  and  mordanting.  The  goods,  after  being 
washed,  are  passed  through  a  warm  solution  of  tannin,  prepared  by  extracting  galls  or  sumac 
with  boiling  water  and  straining,  after  which  they  are  impregnated  with  a  solution  of  alum, 
to  which  sometimes  a  little  chalk  or  carbonate  of  potash  is  added,  or  with  a  solution  of  ace- 
tate of  alumina,  prepared  by  double  decomposition  from  alum  and  acetate  of  lead.  Some- 
times the  alum  is  dissolved  in  the  decoction  of  galls,  and  thus  the  two  operations  are  com- 
bined into  one.  The  goods,  after  being  dried  in  the  stove,  passed  through  hot  water  con- 
taining chalk,  and  rinsed,  are  now  ready  to  be  dyed.  It  has  been  asserted  that  the  galling 
is  not  an  essential  part  of  the  process,  that  it  merely  serves  to  fix  the  alumina  of  the  mor- 
d.mt,  and  may  l)e  dispensed  with  when  acetate  of  alumina  is  used  instead  of  alum.  It  is 
certainly  dilHcult  to  conceive  how  it  can  permanently  affect  the  appearance  of  the  color, 
since  the  tannin  of  the  galls  is  undoubtedly  removed  from  the  fibre  during  the  subsequent 
stages  of  the  process. 

The  dyeing  is  performed  in  the  usual  manner.  The  materials  employed  arc  madder, 
chalk,  sumac,  and  blood,  in  various  relative  proportions.  The  heat  of  the  dye  bath  is  grad- 
ually raised  to  the  boiling  point,  and  the  boiling  is  continued  for  some  time.  The  part 
played  by  the  chalk  in  dyeing  with  madder  has  been  explained  above.  It  was  formerly 
supposed  that  the  red  coloring  matter  of  the  blood  contributed  in  producing  the  desired  ef- 
fect in  Turkey-red  dveing;  but  to  the  modern  cliemist  this  supposition  does  not  appear 
probable.  Nevertheless,  it  is  certain  that  the  addition  of  Ijlood  is  of  .some  benefit,  though 
it  is  uncertain  in  what  the  precise  effect  consists.  Glue  is  occasionally  employed  in  the 
place  of  blood.  Sometimes  a  second  mordanting  with  galls  and  alum,  and  a  second  dyeing, 
is  allowed  to  succeed  the  first  mordanting  and  dyeing. 

After  being  dyed  the  goods  appear  of  a  dull  brownish-red  color,  and  they  must  therefore 
be  subjected  to  tlie  brightening  process,  in  order  to  make  them  assume  the  bi-ight  red  tint 
required.  For  this  purpose  they  are  first  treated  with  a  boiling  solution  of  soap  and  car- 
bonate of  potash  or  carbonate  of  soda,  and  then  with  a  mixture  of  soap  and  muriate  of  tin 
crystals.  This  operation  is  usually  performed  in  a  close  vessel  under  pressure.  The  alka- 
lies remove  the  brown  coloring  matters  and  the  excess  of  fat  aciil  contained  in  the  color, 
and  the  tin  salt  probalily  acts  l)y  extracting  a  portion  of  the  alumina  of  the  mordant,  and 
substituting  in  its  [ilace  a  ()uantity  of  oxide  of  tin,  which  has  the  ell'ect  of  giving  the  color 
a  more  fiery  tint.  The  last  finish  is  given  to  the  color  by  treating  the  goods  with  bran  or 
witii  cliloride  of  soda. 

The  chief  objects  which  the  Turkey-red  dyer  seeks  to  attain  are,  1st,  to  obtain  the  de- 
sired eilect  with  the  least  possible  expenditure  of  time  and  niateiial;  2d,  to  i)roduce  a 
perfect  uniformity  of  tint  in  the  same  series  of  dyeings;  and,  3d,  to  impart  to  his  goods  a 
color  which,  though  perfectly  duraljle,  shall  be  fixed  as  much  as  possible  on  tlie  surface  of 
the  fal)ric.  The  last  point  is  one  of  imjiortance  in  the  case  of  calicoes  dyed  of  this  color, 
since  this  kind  of  goods  is  much  employed  for  the  ])n)dnction  of  a  i)eciili.ir  style  of  prints, 
in  which  poitions  of  tlie  color  are  discharged,  in  order  eitiier  to  rein.iin  white  or  to  l>c  cov- 
ereil  with  other  c;)lors.  And  if  the  red  dye  is  too  firmly  fixed,  or  too  (KHi)ly  seated,  it  lie- 
comcs  more  dillicult  to  discharge  it.  In  this  respect  the  art  has  in  modern  times  attained 
to  such  a  degree  of  perfection,  that  the  interior  of  each  tliread  of  Turkey-red  cotton  will  be 
found  on  examination  to  be  perfectly  white.  This  is  particularly  the  ca.se  with  the  Turkey 
reds  from  the  establishment  of  .Mr.  Steincr  of  Accrington,  Lancashire,  whose  jiroductioiis  in 
this  branch  of  the  art  of  dyeing  are  also  unrivalled  for  the  brilliancy  and  purity  of  their 
color.     See  Madder  and  Calico  Pui.nti.ng. — E.  S. 


1064 


UREA. 


u 

UREA.  This  is  one  of  the  principal  constituents  of  urine,  beins;  always  present  in  it, 
but  in  variable  quantities:  the  average  quantity  in  healthy  urine  is  about  14  or  15  parts  in 
1,000  of  urine,  but  of  course  this  varies  from  several  circumstances,  as  in  disease,  drinking 
a  large  quantity  of  liquid,  kc.  The  urine  passed  the  first  in  the  morning  gives  a  fair  esti- 
mate of  the  quantity  of  urea  yielded  by  the  urine  of  an  individual.  It  seems  to  be  the  prin- 
cipal form  in  which  the  waste  nitrogenous  compounds  of  the  body  are  eliminated  from  the 
system.  It  is  very  prone  to  decomposition  when  in  contact  with  albumen,  mucus,  or  any 
fermentable  matter ;  and  this  is  the  cause  of  urine,  which,  when  first  passed,  is  generally 
slightly  acid,  becoming  allvaline,  and  a  precipitate  being  formed ;  the  change  being  much 
more  rapid  in  hot  than  in  cold  weather,  the  mucus,  &c.,  beginning  to  ferment  sooner.  The 
urea  is  decomposed  into  carbonate  of  ammonia,  water  being  at  the  same  time  assimilated. 
Cn^NW         +         4H0         =         2(NII^C0') 


Urea.  Water.  Carbonate  of  ammonia. 

The  carbonate  of  ammonia  neutralizes  the  acid  which  keeps  the  phosphates  in  solution, 
and  hence  the  precipitate. 

In  some  diseases  the  quantity  of  urea  in  the  urine  amounts  to  30  parts,  and  even  more, 
in  the  1,000  parts  of  urine. 

It  is  interesting  as  being  the  first  organic  base  which  was  made  artificially.  It  was 
found  that  cyanate  of  ammonia,  which  has  exactly  the  same  ultimate  composition  as  urea, 
when  dissolved  in  water  and  boiled  for  some  time,  became  completely  changed,  neither 
cyanic  acid  nor  ammonia  being  detected  by  the  ordinary  test  in  the  solution,  and  that  it  had 
iu  fact  been  converted  by  a  molecular  change  into  urea. 

NH\c=xo=      =      c=irx-o' 

Cyanate  of  ammonia.  Urea. 

Its  presence  in  the  urine  is  detected  thus :  evaporate  a  portion  of  the  urine  over  a  water 
batli  to  about  one  fourth  of  its  bulk,  and  when  cold  add  half  its  volume  of  pure  nitric  acid, 
when  after  a  little  time  abundant  crystals  of  nitrate  of  urea  will  be  formed. 

The  quantity  of  urea  in  any  sample  of  urine  may  easily  be  estimated  by  a  process  in- 
vented by  Liebig.  It  consists  in  treating  the  urine  with  a  standard  solution  of  pernitrate 
of  mercury.  A  copious  white  precipitate  is  formed,  with  liberation  of  nitric  acid.  As  this 
acid  prevents  the  further  action  of  the  nitrate,  the  urine  is  previously  treated  with  a  solution 
of  two  vols,  of  saturated  baryta  water,  and  one  vol.  of  saturated  solution  of  nitrate  of  baryta, 
which  precipitates  the  phosphates,  and  the  excess  of  baryta  neutralizes  the  nitric  acid  as  soon 
as  it  is  liberated.  The  addition  of  the  nitrate  of  mercury  is  continued  until  the  last  portion 
added  causes  a  yellow  binoxide  of  mercury  instead  of  a  white  precipitate.  The  quantity  of 
urea  present  in  a  given  sample  of  urine  may  thus  be  readily  deduced  from  the  quantity  of 
the  nitrate  required  to  precipitate  it  completely,  the  solution  of  nitrate  of  mercury  being  so 
arranged  that  every  100  grains  of  it  shall  be  equal  to  one  grain  of  urea. 

It  is  also  to  be  noticed  that  no  precipitate  is  formed  in  the  presence  of  common  salt ; 
that  therefore  has  to  be  also  removed  by  addition  of  nitrate  of  silver  before  using  the  nitrate 
of  mercury.  By  an  ingenious  application  of  this  fact,  the  quantity  of  common  salt  in  any 
sample  of  urine  may  also  be  determined  by  the  same  solution  of  nitrate  of  mercurj'.  Urea 
when  in  solution  acts  as  an  alkali  on  test  paper;  it  unites  with  acids  forming  salts,  the  ni- 
trate and  oxalate  being  the  least  soluble  of  them.  Although  urea  is  so  easily  decomposed, 
a  pure  solution  of  it  may  be  kept  a  considerable  time  unchanged. — H.  K.  B. 


V 

VACUUM  PAN.     For  a  description  of  it,  see  Sugar. 

VALUE.  Two  methods  have  been  adopted  for  ascertaining  the  value  of  our  exports; 
one  by  means  of  the  official  value,  the  other  according  to  the  declared  value.  In  Lowe's 
Present  State  of  Eiiyland,  (1822,)  there  is  a  very  succinct  and  clear  account  of  these  meth- 
ods, which  is  here  extracted : — 

"  The  official  value  of  goods  means  a  computation  of  value  formed  with  reference,  not  to 
the  prices  of  the  current  year,  but  to  a  standard,  fixed  so  long  ago  as  1696,  the  time  when 
the  office  of  Inspector  General  of  the  imports  and  exports  was  established,  and  a  Custom- 
house ledger  opened  to  record  the  weight,  dimensions,  and  value  of  the  merchandise  that 
passed  through  the  hands  of  the  officers.  One  uniform  rule  is  followed,  year  by  year,  in 
the  valuation,  some  goods  being  estimated  by  weight,  others  by  the  dimensions,  the  whole 
without  reference  to  the  market  price.  [Worsted  stuffs  are  valued  at  £1  lis.  8c?.  the  piece, 
accordinir  to  MacGregor's  Commercial  Statistics.]  This  course  has  the  advantage  of  exhib- 
iting. «i''i  s'lii'f  accuracy,  every  increase  or  decrease  in  the  quantity  of  our  exports. 


VEGETABLE  EXTEACT. 


1065 


"Xext  as  to  the  value  of  these  exports  in  the  market: — In  1798  there  was  imposed  a 
duty  of  2  per  cent,  on  our  exports,  the  value  of  which  was  taken,  not  by  the  official  stand- 
ard, but  by  the  declaration  of  the  exporting  merchants.  Such  a  declaration  may  be  as- 
sumed as  a  representation  of,  or  at  least  an  approximation  to,  the  market  price  of  merchan- 
dise, there  being  on  the  one  hand  no  reason  to  apprehend  that  merchants  would  pay  a  per- 
centage on  an  amount  beyond  the  market  value,  while  on  the  other  the  liability  to  seizure 
alForded  a  security  against  undue  valuation." 

VEGETABLE  EXTRACT.  In  offering  any  thing  new,  more  especially  as  connected 
with  an  art  so  long  practised  as  that  of  brewing  malt  liquors,  Mr.  Hodge,  whose  patent  we 
are  about  to  describe,  is  fully  aware  that  changes  in  old  established  methods  are  never  re- 
ceived readily.  It  is,  however,  evident  that  there  are  certain  points  to  be  attained  in  the 
production  of  malt  liijuors,  which,  if  carried  out  on  scientific  principles,  would  be  a  great 
boon  to  the  profession. 

The  present  practice  of  first  making  an  extract  of  malt,  and  then  adding  the  hop-leaves 
to  the  wort  in  the  copper,  for  the  purpose  of  getting  out  their  extractive  matter  (in  a  liquid 
already  nearly  to  the  point  of  saturation)  is  not  in  accordance  with  scientific  principles. 

It  is  a  well-known  fact  that,  without  long  boiling,  the  resin,  lupuline,  and  tannic  acid  of 
the  hops  are  not  readily  disengaged  from  the  leaf;  hence  we  find  ail  brewers  say  that  they 
like  a  good,  lonr/,  sharp  boil  to  make  the  beer  keep  well. 

The  two  most  antiputrescent  ingredients  are  the  lupuline  and  tannic  acid ;  but  while 
the  long  boiling  is  going  on  to  get  these  two  ingredients  liberated,  the  volatile  oil,  or  that 
which  gives  the  softening  principle,  as  well  as  the  aroma,  to  t.he  ales,  passes  off  into  the 
atmosphere  and  is  lost,  so  that  the  beer  or  ale  has  a  nasty,  rough,  acrid  taste,  somewhat  like 
gentian  root.  The  great  question  is  ?  what  are  the  constituents  of  wort  liquor  when  drawn 
from  the  mash  tun,  what  do  we  want  to  retain,  and  what  to  get  rid  of:  The  worts  are 
composed  of  water,  saccharine  matter,  starch  in  small  quantity,  albumen,  and  gluten.  The 
saccharine  matter  is  the  only  thing  we  want  to  retain,  save  its  proper  proportion  of  water. 
The  other  ingredients  are  nitrogenous,  and  liable  to  produce  putrid  fermentation. 

Boiling  of  the  worts  is  intended  to  coagulate  the  nitrogenous  matter ;  two  minutes  will 
do  this  at  200°  Fahr.  What  must  now  be  effected  is  to  bring  these  particles  of  coagulated 
matter  into  contact  witli  the  tanning,  resinous,  and  lupuline  properties  of  hop,  rendering 
them  insoluble ;  which  chemical  change  prevents,  in  a  measure,  further  decomposition  for  a 
time,  until  they  are  nearly  all  got  rid  of  by  fermentation  or  after  precipitation. 

There  cannot  be  a  doubt  that  boiling  worts  to  a  certain  extent  is  necessary,  but  long 
boiling  is  decidedly  injurious,  as  there  must  be  a  decomposition  of  the  saccharine  matter 
going  on,  as  well  as  a  reglutinization  of  the  albumen  and  other  compounds,  unless  these 
particles  are  immediately  brought  into  contact  with  those  properties  of  the  hop  to 
arrest  it. 

All  these  difficulties  can  be  prevented  by  first  making  an  extract  of  hop  in  a  close 
digester,  as  is  represented  in  the  enclosed  drawing,  /f^.  674.  The  most  volatile  properties 
can  either  be  distilled  over,  or  drawn  off  from  the  top,  and  added  to  the  worts  after  they 
are  cooled,  and  before  fermentation.  The  keeping  princii)le  of  the  hop  will  then  be  drawn 
off  in  a  strong  decoction  and  added  to  the  worts  after  they  are  allowed  to  boil  a  few 
minutes,  when  the  particles  of  nitrogenous  matter  will  be  immediately  changed,  retaining 
the  aroma  and  other  delicate  properties  of  the  hop. 

Hence  the  advantage  of  the  separate  extract  of  hop,  in  vessels  where  the  temperature 
can  be  regulated  to  the  greatest  nicety,  and  where  the  air  cannot  come  into  contact  to 
change  the  color  of  the  liquid  or  lose  the  aroma. 

Another  advantage  in  this  process  is,  not  allowing  the  hop  leaf  to  go  into  the  wort, 
thereby  saving  one  in  every  30  barrels  brewed,  or  3  per  cent,  on  all  malt  extract,  which  to 
some  brewers  would  amount  to  £20,000  per  annum. 

Fir/s.  674,  1  ami  2,  (.v  and  a,)  are  two  digesters,  which  are  supplied  with  water  to  the 
interior  at  212'  Fahr.  This  is  admitted  by  the  water-pi[)e  passing  through  tiie  hollow 
journal,  and  thence  down  the  side  pipe  in  the  interior  of  the  vessel  below  the  perforated 
platform  b'.  The  hops  are  placed  between  these  platforms  b  b  and  b'.  Steam  is  let  on  from 
the  steam-pipe  passing  through  the  hollow  journal,  and  into  the  steam-jacket  c,  c,  c,  which 
keep  up  the  temperature  of  the  mass  at  or  above  212°  Fahr.,  as  may  be  deemed  necessary  ; 
at  the  same  time  no  steam  is  allowed  to  escape,  hence  the  whole  of  the  aromatic  properties 
of  the  hop  are  preserved.  This  is  done  in  two  ways  ;  first,  by  drawing  off  the  top  of  the 
extract  through  the  cock  e,  (this  is  added  to  the  beer  after  it  is  cool;)  or,  the  hop  oil  is 
distilled  over  by  means  of  the  hood  f,  and  condenser  «,  and  is  run  off  through  the  cock  ii 
fiij.  675.  The  cover  D  is  then  drawn  up  by  the  cliain  and  counter-weight.  The  extract  is 
then  drawn  off  through  the  bottom  cock  j,  and  is  added  to  the  boil.  The  perforated  plat- 
form is  removed,  and  the  vessel,  which  swings  on  the  trunnions,  is  turned  upside  down  and 
the  spent  hops  drop  into  a  press.     See  Brewi.vg. 

Cooliriff. — The  quicker  worts  are  cooled  down  to  the  fermenting  temperature  after  being 
boiled,  the  better.  Tlie  less  it  is  expo.sod  to  the  action  of  the  atmosphere  the  less  liable 
it  is  to  absorb  oxygen,  preventing  acetous  fermentation. 


1066 


VEGETABLE   EXTRACT. 


Rapid  cooling  to  all  brewers  is  of  vital  importance,  for  if  wort  be  permitted  to  come 
into  contact  with  the  air  during  the  time  its  caloric  is  given  off,  aciditv  must  set  in,  espe- 
cially in  summer  time. 

The  best  method  to  cool  worts  is  that  which  is  shown  and  described  in  the  drawing 
annexed,  _^^.  675. 


VENTILATION  OF  MINES. 


1067 


The  worts  are  passed  through  copper  tubes,  thoroughly  tinned.  Instead  of  passing  a 
current  of  water  round  these  tubes,  a  dew  jei  of  water  is  sprinkled  all  over  the  outer  sur- 
f;ice,  at  the  same  time  a  current  of  cold  air  is  brought  into  contact  with  the  moist  surface  of 
the  tube,  so  that  as  fast  as  the  molecules  of  caloric  are  transmitted  to  the  water  through  the 
metal  tubes,  they  are  blown  away,  giving  place  to  others.  By  this  process  heat  from  liquids 
can  be  abstracted  more  rapidly  than  by  any  other.  In  fact,  worts  can  be  brought  down  to 
freezing  temperature,  although  tho  water  used  may  be  80'  to  lUO"  Fahr.  Another  great 
advantage  is,  that  the  quantity  of  water  used  is  about  one-half. 

These  tubes  can  be  cleaned  with  a  brush  with  perfect  ease. 

VEXTILATION  OF  MIXES.  In  our  subterranean  operations,  especially  where  quan- 
tities of  carbonic  acid  are  constantly  being  produced  by  respiration  and  combustion,  and 
where,  especially  in  our  coal  mines,  the  workmen  are  constantly  exposed  to  the  efflux  of  ex- 
plosive gas — light  carburetted  hydrogen — it  becomes  necessary  to  adopt  the  means  of  remov- 
ing, as  rapidly  as  possible,  the  air  by  which  the  miner  is  surrounded.  See  Strute's  Mine 
Ventilator. 

Description  of  the  Ventilating  Fan  at  the  Abercarn  Collieries. — The  mode  of  ventilation 
that  is  still  generally  used  in  the  collieries  of  this  country  is  the  old  furnace  ventilation, 
where  the  required  current  of  air  through  the  mine  is  maintained  by  the  rarefaction  of  the 
column  of  air  in  the  ascending  shaft,  by  means  of  a  large  fire  kept  constantly  burning  at  the 
bottom  of  the  shaft.  In  Belgium  and  France,  on  the  contrary,  this  plan  is  almost  super- 
seded by  the  use  of  machinery  to  maintain  the  current  of  air ;  as  the  furnace  ventilation, 
although  possessing  the  important  advantage  of  great  simplicity  and  freedom  from  liability 
to  derangement  from  dis- 
turbing causes,  has  some 
serious  objections  and 
deficiencies,  and  in  some 
cases  becomes  so  imper- 
fect a  provision  for  ven- 
tilation as  to  render  a 
better  system  highly  de- 
sirable and  even  neces- 
sary. 

Mr.  E.  Rogers,  having 
occasion  to  ventilate  the 
workings  in  some  ex- 
tensive and  very  fiery 
coal  seams  recently  won 
at  Abercarn  in  South 
Wales,  under  circum- 
stances where  the  fur- 
nace ventilation  could 
not  be  applied,  after 
carefully  collecting  every 
accessible  information 
as  to  the  ventilating 
machines  used  in  Great 
Britain  and  on  the  Con- 
tinent, came  to  the  con- 
clusion tliat  a  plan  of 
machine  proposed  for  the 
purpose  some  years  since 
by  Mr.  James  Nasmyth 
would  be  the  most  suita- 
ble and  effective.  After 
consultation  with  Mr. 
Nasmyth,  it  was  resolved 
to  test  the  principle  and 
plan  by  actual  practice  ; 
and  the  ventilating  fan 
described  was  ma(le  at 
Patricroft  by  Mr.  Nas- 
myth, and  is  erected  at 
the  Abercarn  Collieries. 
The  general  arrange- 
ments of  the  top  of  the 
shaft  and  the  ventilating  fan  are  shown  m  figx.  CYG  and  677.  Fig.  678  is  a  side  elevation 
of  the  fan  and  engine,  to  a  larger  scale  ;  anil  jf^r.  677  a  vertical  section  of  the  fan. 


1068 


VENTILATION  OF  MINES. 


The  fan  a  A,f(j.  677,  is  13i^  feet  diameter,  with  8  vanes,  each  3  feet  6  inches  wide  and  3 
feet  long.  It  is  tixcd  on  a  horizontal  shaft,  n,  8  feet  7  inches  in  length  from  centre  to  cen- 
tre of  the  boarhigs,  which  are  9  inches  long  by  4^  inches  diameter.      The  vanes  are  of  thin 

plate  iron,  and  carried  bj'  forked 
wrought-iron  arms  secured  to  a 
centre  disc,  c,  fixed  upon  the 
shaft  B.  The  fan  works  within  a 
casing  d  d,  consisting  of  two  fixed 
sides  of  thin  wrought  plate,  en- 
tirely open  round  the  circumfer- 
ence and  connected  together  by 
stay  rods ;  the  sides  are  3  inches 
clear  from  the  edges  of  the  vanes, 
and  have  a  circular  opening  6  feet 
diameter  in  the  centre  of  each, 
from  which  rectangular  wrought- 
iron  trunks,  E  K,  are  carried  down 
for  the  entrance  of  the  air ;  the 
bearings  for  the  fan  ,«haft  b  being 
fixed  in  the  outer  sides  of  these 
trunks,  A\hich  are  strengthened 
for  the  purpose  by  vertical  cast- 
iron  standards  f  bolted  to  them, 
and  resting  upon  the  bottom 
foundation  stone  g. 

The  two  air  trunks  e  e  join  to- 
gether below  the  fan,  as  shown 
iu  />(/.  67(5,  and  communicate 
with  the  pit  ii  by  means  of  a  hor- 
izontal tunnel,  i,  which  enters  the 
pit  at  21  feet  depth  from  the  top. 
The  fan  is  driven  by  a  small 
direct-acting  non-condensing  en- 
gine, K,  which  is  fixed  upon  the 
face  of  one  of  the  vertical  cast- 
iron  standards  f,  and  is  connected 
to  a  crank  on  the  end  of  the  fan 
shaft  B.  The  steam  cylinder  is 
12  inches  diameter  and  12  inches 
stroke,  and  is  woiked  by  steam 
from  the  boilers  of  the  winding 
engine  of  the  pit,  at  a  pressure 
of  about  13  lbs.  per  square  inch. 
The  eccentric  l  for  the  slide  valve 
is  placed  just  inside  the  air  trunk 
E,  and  works  the  valve  through  a 
short  weigh  sliaft,  m,  with  a  lever 
on  the  outside. 

The  pit  II,  ff/.  C76,  is  of  an 
oval  form,  10  feet  by  18  feet,  and 
divided  near  the  centre  by  a  tim- 
ber brattice,  N,  the  one  side  form- 
ing the  upcast  shaft  and  the  other  the  downcast.  Both  of  these  are  used  for  winding,  and 
the  cages  o,  in  which  the  irucks,  &c.,  arc  brought  up,  work  between  guides  fixed  to  the 
timbering  of  the  pit.     The  pumps  p  are  placed  in  the  downcast  shaft. 

In  order  to  allow  of  the  upcast  shaft  being  used  for  winding,  the  top  is  closed  by  an  air 
valve,  R,  which  is  formed  by  simply  boarding  up  the  under  side  of  the  oidinavy  guard  upon 
the  mouth  of  the  sliaft,  leaving  only  the  hole  in  the  centre  through  which  the  chain  woiks. 
This  air  valve  R  is  carried  up  by  the  cage  o,  on  arriving  at  the  top  of  the  shalt,  as  in 
Jjr/.  676,  and  then  drops  down  again  flat  u[)on  the  opening,  when  the  cage  is  again  lowered. 
During  the  time  that  thc'valve  is  lifted,  its  place  is  occupied  by  the  close  bottom  of  Ihe 
cage  o,  which  nearly  fills  the  rectangular  opening  left  at  the  top  of  the  shaft.  By  this  sim- 
])le  means  it  is  found  practically  that  a  complete  provision  is  made  for  keeping  the  top  of 
the  upcast  shaft  closc(l,  and  maintaining  a  uniform  current  of  air  up  the  shaft ;  for  the 
leakage  of  air  dov.-nwards  through  tlie  top  whilst  the  cage  is  iu  the  act  of  opening  or  closing 
the  air  valve,  and  through  the  small  area  that  always  remains  open,  is  found  to  be  f|uito  im- 
material, and  the  surfjlus  ventilating  power  of  the  fan  is  amply  sufficient  to  provide  against  it. 


WASHING  COAL. 


10G9 


In  the  original  construction  a  more  perfect  air  valve  was  supposed  to  be  requisite,  antl 
was  provided  by  the  inclined  flaps  s  s,  which  are  fixed  just  above  the  horizontal  tunnel  i. 

These  are  fitted  closely  together,  leaving  only  a  small  opening  in  the  centre  for  the 
chain  to  pass  through,  and  were  intended  to  be  opened  by  the  ascending  cage  coming  in 
contact  with  them,  closing  again  directly  by  means  of  balance  weights  before  the  air  valve 
R  at  the  top  of  the  shaft  was  opened,  so  as  to  preserve  a  thorough  closing  of  the  top  of  the 
shaft.  The  flaps  were  to  be  opened  again  by  a  lever  from  the  top  to  allow  the  cage  to  de- 
scend. Uowever,  it  was  found  on  trial  that  the  valve  r  at  the  top  was  amply  sufficient ; 
and  consequently,  although  the  other  valves  were  also  provided,  they  have  never  been  put 
into  use. 

The  total  depth  of  the  pit  is  neariy  300  yards,  and  at  a  depth  of  120  yards  a  split  of  air 
is  taken  off,  and  coursed  through  workings  from  which  coal  and  fire-clay  are  got ;  the  larger 
portion  of  the  air  descends  to  the  bottom  of  the  pit,  and  is  there  split  into  many  courses, 
to  work  two  separate  seams  of  coal  and  a  vein  of  iron  stone.  The  total  length  of  road  laid 
with  plates  or  rails  in  the  workings  is  about  7  miles,  and  the  working  faces  amount  to 
nearly  double  that  distance.  The  longest  distance  that  is  traversed  by  any  single  course  or 
split  of  air,  in  passing  from  the  downcast  to  the  upcast  shaft,  is  nearly  2  miles.  The  quan- 
tity of  materials  raised  from  the  pit  is  about  500  tons  daily. 

The  following  Table  gives  the  results  of  a  series  of  experiments  made  with  this  ventilat- 
ing fan  by  Mr.  K.  S.  Roper,  showing  that  the  quantity  of  air  delivered  at  the  velocities  of 
60  and  80  revolutions  of  the  fan  per  minute  is  45,000  and  66,000  cubic  feet  per  minute, 
with  a  velocity  of  current  of  782  and  1,037  lineal  feet  per  minute  respectively,  or  about  9 
and  12  miles  per  hour ;  and  the  degree  of  vacuum  or  exhaustion  in  the  upcast  shal't  is  "5 
and  '9  inch  of  water  respectively. 

Synopsis  of  Experiments  on  Fan  Ventilation. 


Heiglit  of 

'lemperatura                   i^  ^ 

'■<    . 

a  "3 

Biirometer. 

by  Fahrenheit's  Thermomoter.      °  3 

go  '•<  •■ 

Sj 

u"   . 

•2  £ 

Is. 

^1 

Water  gni 

Velocity  of 

in  feet  p 

minute 

®  3 

1  0. 
0 

<  = 
1/1 

^1 

^1 

"3  « 

m  a 

i1 

feet 

c.  feet 

Mean  of  twelve  experi- 

ins.    1     ins. 

deg3. 

degs. 

degs. 

dega. 

revs. 

ins. 

p.  min. 

p.  min. 

lbs. 

lbs. 

ments.  Natural     Ven- 

tilation        -        -        . 

29-61 

30-60 

41-10 

51-73 

55-56 

4S-00 

-15 

446-0 

24,825 

Mean    of    four    experi- 

1 

nifents.  Fan  VentiLation 

29-85 

30-85 

8S-10 

50-10 

53-93 

47-30 

60 

-50 

781-8 

45,187 

13-0 

17-4 

Mean    of    five    experi- 

ments, Fan  Ventilation 

29-65 

30-61 

41-40 

50-70 

55-10 

48-70 

80 

•90 

1037-0 

50,555 

1-93 

23-2 

The  speed  at  which  the  ventilating  fan  is  usually  worked  is  about  GO  revolutions  per 
minute,  giving  a  velocity  at  the  circumference  of  the  fan  of  2,545  feet  per  minute;  45,000 
cubic  feet  of  air  per  minute  are  then  drawn  through  the  mine,  nearly  one-third  of  which 
ventilates  the  upper  workings,  and  the  rest  passes  through  the  lower  workings. 

In  these  experiments  the  mode  adopted  for  ascertaining  the  velocity  of  the  air  currents 
was  by  calculation  from  the  difference  of  pressure,  as  observed  by  means  of  a  carefully  con- 
structed vacuum  gauge,  the  result  being  cheeked  by  the  anemometer  and  by  the  time  of 
passage  of  the  smoke  of  powder  fired  at  fixed  distances  by  means  of  wires  from  a  voltaic 
battery  at  the  top  of  the  shaft. 

For  further  information  upon  this  subject  see  articles,  Mines,  Ventilation  of;  Pit- 
coal  ;  and  Ventilation,  vol.  ii. 

VERJUICE.  {Verjux^Yw;  Arp-cst,  Germ.)  A  har.sh  kind  of  vinegar,  containing  much 
malic  acid,  made  from  the  expressed  juice  of  the  wild  crab  apple. 

VINE  BLACK.  A  black  procured  by  charring  the  tendrils  of  the  vine  and  levigatuig 
them. 

w 

WASHING  COAL.  M.  Berard  is  the  inventor  of  a  very  successful  apparatus  for  puri- 
fying small  coal.  He  exhibited  his  arrangement  at  the  Great  Exhibition  of  1851,  receiving 
the  council  medal.  Tlie  decoration  of  the  Legion  of  Honor  and  a  gold  medal  was  also 
awarded  to  him  at  the  Taris  Exhibition  in  1855.  This  apparatus,  to  be  presently  described, 
elfects,  witliout  any  manual  labor,  the  following  operations: — 

1st.   The  sorting  of  the  coal  by  throwing  out  tlie  larger  pieces. 

2d.  Breaking  the  coal,  which  is  in  pieces  too  large  to  be  subjected  to  the  operation  of 
washing. 

3d.  Continuous  and  perfect  purification  of  the  coal. 

4th.  Loading  the  purified  coal  into  wagons. 

5th.  Loading  the  refuse  (pyrites  or  schist)  into  Viagons  for  removal. 


1070 


WASHING  COAL. 


The  power  required  for  the  apparatus  is  that  of  from  four  to  five  horses,  and  the  ma- 
chine can  operate  upon  from  80  to  100  tons  of  coal  in  about  twelve  hours,  if  fitted  up  near 
the  colliery.  The  expense  of  the  operation  of  purifying  is  stated  to  consist  solely  in  the 
wages  of  the  workmen  charged  to  conduct  the  labor  of  the  machine. 

The  following  description  of  the/y.5.  GfO  and  680,  will  render  the  arrangements  of  M. 
Bcrard's  machine  readily  intelligible. 


^     ""'^^^^^^ 


The  coal  is  cariied  from  the  mine  on  a  staging,  for  example,  and  the  tram-wagon  b  is 
unloaded  into  a  hopper,  c,  either  by  opening  the  bottom  or  by  tilting  it  (as  in  the  position 
represented  by  the  dotted  lines  b)  by  means  of  a  lever.  It  falls  afterward  cither  on  to  a 
ta!»le  or  a  movable  grating,  d,  formed  of  frames,  or  of  a  series  of  stages,  of  sloping  perfor- 
ated plates,  which  immediately  sorts  it  into  as  many  sizes  as  there  are  perforated  plates. 

fiSO 


This  grating  is  suspended  out  of  a  perpendicular  by  four  chains  or  iron  rods,  c  c,  fixed 
to  the  framework  of  the  staging  A.  It  is  moved  by  means  of  a  cam  motion  (an  arrange- 
ment of  a  cam  and  tongue  mentonnct)  c',  and  falls  back  by  its  own  weight  against  the 
stops,  which  produce  concussions  or  vibrations  favorable  to  the  clearing  out  of  the  holes  and 
to  the  descent  of  the  materials.  The  motion  communicated  to  the  grating  admits  of  a  mucli 
less  inclination  being  given  to  it  than  would  be  the  case  if  it  were  fixed :  the  sorting  is  ef- 
fected quicker  and  more  perfectly,  besides  which  the  diflerences  of  level  which  it  is  neces- 
sary to  preserve  are  maintained. 

The  larger  pieces  rejected  by  the  first  plate  reach  the  picking  table  e,  where  a  laborer 
picks  out  the  largest  stones  and  extraneous  sub.^tances  as  fragments  of  castings,  iron,  &e. 

The  fragments  which  have  passed  through  the  upper  ])late,  and  are  retained  by  that  be- 
low, descend  direct  to  the  crushers  f  f',  situated  below.  Lastly,  the  fine  poitions  of  the 
coal  which  have  passed  through  the  second  perforated  plate  fall  on  to  a  solid  bottom,  a', 
wl-.ence  they  arc  thrown,  delivered  direct  into  the  pit  l)y  means  of  a  fixed  shoot,  c. 

The  crushing  cylinders  f  f'  are  made  with  a  covering  of  cast-iron,  mounted  on  an  iron 
.'^haft.  This  covering  can  lie  easily  replaced  when  worn  out.  It  has  on  its  surface  small 
grooves,  which  are  usually  placed  longitudinally,  parallel  with  the  axis  of  the  cylinder,  in 
order  to  avoid  the  .^lipping  of  the  substances  operated  on.  But  it  is  also  necessary  to  crush 
fragments  of  slate  which  gain  admission  with  the  coal,  and  these  consisting  of  thin,  flattened 
lanjina?,  it  would  be  necessary  to  bring  the  cru.sher  closer  than  would  be  required  to  reduce 
the  coal  which  is  of  a  more  cubical  form  to  the  jiropcr  size. 

In  order  to  obviate  this  difficulty  another  series  of  gioovcs  are  formed  on  the  surfaces 
of  the  cruslier  transversely  to  those  already  descriljed,  the  intersection  of  the  two  producing 


WASHING  COAL.  1071 

projections  in  the  form  of  quadrangular  pyramids,  with  slightly  rounded  tops.  In  coming 
between  the  projections  of  the  crushers  the  fragments  of  slate,  being  unable  to  pass,  are 
broken  up  without  reducing  the  coal  to  a  smaller  size  than  is  recjuired. 

When  the  coal  has  undergone  a  preliminary  sii'ting,  which  has  removed  all  the  pieces 
exceedin'^  6  or  7  centimetres  in  size,  one  pair  of  crushers  is  sulficient.  In  that  case  the 
grating  may  be  dispensed  with  altogether  by  discharging  the  coal  direct  into  the  pit,  and 
returning  from  the  sifter  to  the  washer  the  pieces  of  coal  which  have  not  been  able  to  pass 
beyond  the  first  perforated  plate. 

'  The  small  coal  resulting  from  the  washer,  or  from  the  sifter,  by  means  of  the  jigger,  is 
di'livered  into  a  common  pit  placed  under  the  washers.  The  pit  is  shaped  like  an  inverted 
quadrangular  pyramid,  the  three  laces  of  which  are  inclined  to  one  another  at  an  angle  of 
45  \  to  facilitate  ihe  descent  of  the  substance,  and  the  fourth  is  usually  vertical.  It  is  on 
the  latter  that  an  opening  is  made,  which  is  regulated  by  a  flood-gate. 

An  elevator,  formed  of  an  endless  chain,  with  buckets,  raises  the  coal  from  the  bottom 
of  the  pit,  places  itself  sufficiently  high  to  allow  of  the  final  discharge,  which  may  take  place 
iato  the  wagon. 

The  rate  of  ascent  of  the  buckets  and  their  capacities  are  calculated  so  as  to  raise  160 
to  200  tons  of  coal  in  the  working  hours ;  but  this  quantity  may  be  diminished  by  means  of 
the  flood-gate  in  the  pit. 

The  coal  discharged  by  the  elevator  falls  on  the  sorter,  which  ought  immediately  to  di- 
vide it,  according  to  size,  and  distribute  it  to  the  ferry-boats. 

The  classifier  is  formed  of  a  kind  of  oblong  rectangular  chest,  made  of  iron  plates,  in 
the  inside  of  which  are  placed  stages  of  perforated  plates,  the  apertures  in  which  decrease 
in  a  downward  direction.  Suflicient  space  is  allowed  between  each  plate  for  the  motion  of 
the  materials.  At  the  bottom  of  the  perforated  plates  are  disposed  inclined  planes  for 
throv/ing  on  one  side  the  product  of  the  sifting,  which  escapes  through  a  slope  made  on  the 
side  of  the  sifter.  A  bottom  fixed  to  the  classifier  itself,  and  like  it  movable,  receives  the 
dust  in  the  finest  numbers,  if  the  sifting  has  been  effected  in  the  dry  way,  or  else  this  bot- 
tom is  immovable  and  fixed  to  longerons  which  support  the  classifier,  if  the  sifting  takes 
place  in  water,  as  we  are  about  to  point  out. 

The  classifier  is  suspended  by  two  or  three  pairs  of  articulated  handles  turning  on  axles 
fixed  to  longerons:  by  that  means  it  enjoys  an  extreme  freedom  of  motion  in  a  longitudinal 
direction.  A  rapid  reciprocating  motion  is  communicated  by  a  "  biellc,^''  which  receives  the 
action  of  a  bent  axle  firmly  estal)lished  on  a  foundation  fixed  on  the  principal  wall  of  the 
chamber  of  the  machine.  The  motion  of  rotation  is  communicated  to  the  axle  by  the  dis- 
position of  an  iron  pinion  d^anr//.e  working  into  a. 

The  bac  is  formed  of  a  rectangular  chest  in  cast-iron,  l',  one  part  of  the  bottom  of  which 
is  inclined  at  45^,  the  other  lower  parts  remaining  horizontal. 

Opposite  one  of  the  lesser  sides  of  the  rectangle  is  placed  a  cylinder,  o,  opening  into  the 
oblong  chest  at  about  half  its  height.  The  chest  l'  is  prolonged  under  the  cylinder,  in  or- 
der to  increase  the  stability  of  the  system  and  the  capacity  of  the  drain-well,  (puisard.) 

A  cast-iron  box,  u  m',  is  firmly  fixed  in  the  interior  of  the  bac,  on  flanges  of  cast-iron 
with  vertical  fiices.  This  box  has  a  slight  inclination  from  m  toward  m'.  It  is  covered  with 
a  perforated  plate,  usually  of  copper,  fastened  to  the  frame  by  a  number  of  iron  pins  or 
bolts  easy  of  replacement.  The  size  of  the  holes  varies  according  to  that  of  the  matters 
brought  into  the  bac. 

A  cast-iron  door,  n,  traverses,  opening  outward,  is  fixed  at  a  slight  height  above  the 
frame,  serving  as  a  kind  of  partition  dividing  the  materials  in  the  bac,  and  against  it  a  flood- 
gate, n',  by  means  of  which  the  opening  beneath  the  cast-iron  door  may  be  closed  at  pleasure. 

A  counter  flood-gate,  n',  is  placed  at  the  lower  extremity  of  the  frame ;  in  raising  it  a 
barrier  is  formed  of  varialjle  height,  by  means  of  which  the  substances  between  the  flood- 
gate and  counter  flood-gate  may  be  arrested. 

A  piston,  c,  receives  from  the  machine  a  sufficiently  rapid  reciprocating  motion. 

Every  thing  being  tlius  arranged,  if  the  l>ac  is  su[)posod  to  l)e  filled  with  water  to  the 
level  of  the  front  face  at  n',  and  that  the  substances  to  be  washed  fill  the  space  in  (he  bae 
between  tliis  level  and  the  perfoiatcd  plate  of  the  frame,  the  piston  \^■orking  upward  and 
downward  will  press  the  water  in  the  body  of  the  cylinder,  and  will  force  it  l)y  its  iiiconi- 
[)res.sibility  to  pass  through  the  holes  in  tlie  perforated  plate;  it  will  establish  aliove  this 
[ilate  an  ascending  current,  which,  if  of  sulficient  power,  will  raise  the  substances  sul)m('rged. 

The  resistance  to  the  rise  of  each  body  will  be  in  proportion  to  its  specific  gravity,  an<l 
tlie  height  it  will  be  carried  will  follow  an  inverse  law,  supposing  the  fragments  to  be  of 
nearly  equal  sizes. 

The  slates  which  fall  over  the  counter  flood-gate  fall  into  a  pocket  or  reservoir,  n,  whence 
they  are  discharged  on  opening  a  flood-gate,  k'.  Pressed  by  the  upper  column  of  water, 
thi'v  slide  witli  a  slight  admixture  of  water  on'tlie  inclined  plane  k'  n',  whicli  can  be  ])ierced 
with  holes;  t!io  water  escapes,  atul  the  slate  only  falls  directly  into  the  wagon  of  dis- 
charge. 


10< 


WASHING  COAL. 


The  bent  axle  of  transmission,  s  s,  moves  in  a  groove  turning  on  a  pivot  at  its  extremity. 
The  rotation  of  the  axle  comnuinicates  an  oscilhiting  motion  to  it. 

The  deposit  formed  in  the  drain-well  is  emptied  through  an  opening  of  the  flood-gate 
placed  at  the  lower  part.  An  ojjening  serving  as  a  man-hole  is  reserved  for  effecting  inter- 
nal repairs  without  the  necessity  of  raising  the  frame. 

All  coal  contains  a  portion  of  earthy  matters  or  impurities  which,  in  the  form  of  bands 
or  scales,  are  generally  in  some  degree  apparent  to  the  eye,  and  constitute  the  ashes  and 
clinker  left  by  combustion.  The  small  coal  which  is  sent  out  of  mines  necessarily  contains 
a  still  larger  proportion,  frequently  exceeding  10  per  cent.,  consisting  chiefly  of  shale  and 
iron  pyrites  derived  from  the  roof  or  floor  of  the  seam  of  coal,  or  from  the  bands  of  impu- 
rities interstratified  with  it.  Generally  these  impurities  are  so  incorporated  with  the  mass 
of  the  coal  that  it  must  be  crushed  in  order  sufficiently  to  detach  them.  The  pyrites,  which 
contains  nearly  the  whole  of  the  sulphur  found  in  coal  scams,  is  well  known  to  be  very  in- 
jurious either  in  a  heating  or  smelting  furnace,  in  the  manufacture  or  working  of  iron,  in 
gas-making,  in  coking,  and  other  processes. 

Many  seams  of  coal  already  sunk  to,  or  portions  of  seams  in  work,  are  left  under  ground 
as  unsalable  in  consequence  of  the  impurities  they  contain.  Small  coal  sells  at  a  low  price, 
chiefly  in  consecpience  of  its  impurities  and  the  defective  coking  property  which  they  occa- 
sion. It  has  been  estimated  that  an  amount  not  far  short  of  the  quantity  of  coal  sold  is 
sacrificed  in  producing  a  commercial  article  of  adequate  quality  and  description.  The  enor- 
mous consumption  of  coal  in  this  country,  amounting  to  70  millions  of  tons  per  annum, 
renders  the  utilization  of  a  larger  portion  of  the  more  valuable  seams  now  in  course  of  being 
exhausted,  and  the  bringing  into  the  market  of  other  seams,  olijects  of  national  importance. 

The  differences  between  the  specific  gravities  of  coal  and  its  impurities,  allow  of  their 
being  separated  by  the  action  of  water  when  sufficiently  crushed.  The  water  process 
hitherto  most  commonly  adopted  is  that  known  as  "jigging,"  which  consists  in  forcing  the 
water  alternately  up  and  down  through  the  mass  of  coal.  The  downward  current  of  water 
in  "jigging"  is  prejudicial,  and  entails  a  large  sacrifice  of  the  finer  particles  of  the  best 
coal ;  whilst  the  upward  current,  from  its  rapidity  and  irregularity,  is  costly  both  in  time 
and  power,  besides  failing  to  effect  the  more  perfect  separation  which  is  obtained  by  a  slow, 
continuously  ascending  or  pulsating  current,  regulated  to  the  proportion  of  shale  in  the 
coal,  and  to  the  size  of  the  particles  to  be  acted  upon. 

MackwortKs  patent  coal  purifier. — In  the  late  Mr.  Herbert  Mackworth's  purifier,  jig. 
G81,  the  water  ascends  with  a  velocity  of  an  inch  or  two  in  a  second.     It  is  sufficient  to 


DatictR  rra/\p~~- 


keep  the  particles  in  constant  agitation,  and  the  area  of  the  separator  can  be  reduced  to  a 
small  fraction  of  its  former  size.  The  coal  is  supplied  into  the  machine  in  a  uniform 
stream,  and  as  it  is  purified  is  raised  out  of  the  water  on  to  a  perforated  plate,  and  delivered 


WASHING  COAL.  1073 

by  the  coal-sweep  into  a  long  perforated  shoot,  down  which  it  descends  into  the  tram  or 
wagon  placed  to  receive  it.  The  purified  coal  is  thus  obtained  for  coking  and  otlicr  pur- 
poses in  a  comparatively  drier  state.  Tlie  shale,  which  has  during  the  so[)aratiou  accunm- 
lated  in  the  shale-box,  will  discharge  itself  into  anotlier  tram  without  stopping  the  machine, 
if  the  shale  valves  are  fiist  closed  by  the  valve  lever  bel'ore  throwing  open  the  shale  door. 
The  pump,  or  agitator,  is  capable  of  throwing  from  50  to  200  gallons  of  water  per  minute, 
according  to  the  size  of  the  macliine.  The  endless  band  rises  or  lowers  the  coal  from  the 
hopper  into  which  the  coal  trams  arc  tipped. 

The  advantages  of  the  machine  may  be  thus  summed  up : — 

1st.  The  more  perfect  separation  of  the  impurities.  If  the  coal  is  not  sufTiciently  crush- 
ed, even  the  fragments  of  coal  containing  shale  or  pyrites  can  be  separated  as  well  as  the 
shale,  by  regulating  the  velocity  of  the  water.  By  increasing  the  .-^peed  of  the  machine  and 
the  velocity  of  the  water,  the  separation  of  the  impurities  may  be  limited  to  any  extent 
desired. 

2d.  The  saving  of  coal.  This  may  be  estimated  at.  from  (>d.  to  1.5.  CcZ.  per  ton.  The 
ordinary  washing  processes  sacrifice  more  than  20  per  cent,  in  weight,  of  which  more  than 
one  half  is  the  best  coal.  In  this  machine  the  water  does  not  pass  out,  but  is  used  over 
and  over  again  in  a  continuously  circulating  stream.  The  loss  of  coal  does  not  exceed  2 
per  cent.,  and  is  generally  under  1  per  cent. 

3d.  The  economy  in  the  power  required  to  work  the  machine.  1 -horse  power  will  suf- 
fice to  work  a  machine  with  pump  and  elevator  capable  of  purifying  50  tons  of  coal  per  day. 

4th.   The  saving  in  manual  labor. 

5th.  The  quantity  of  water  required  is  comparatively  insignificant.  A  small  supply  of 
water  is  required  to  replace  that  absorbed  by  the  wetting  of  the  shale  and  coal. 

6th.  The  coal  is  delivered  drier  than  by  any  other  existing  process. 

Vth.  The  largest  machine  stands  in  an  area  of  9  feet  square,  and  motion  can  be  given 
off  any  existing  engine  by  a  strap  to  a  pulley  making  40  revolutions  per  minute,  at  a  height 
of  about  12  feet  al)ove  the  ground.  The  height  given  to  the  machine  is  for  the  purpose  of 
passing  trams  underneath  it  to  receive  the  purified  coal  and  shale  as  they  are  delivered. 
The  machine  requires  no  foundation,  and  is  easily  removable. 

8th.  The  great  economy  of  the  process  in  every  point  of  view  is  important  to — 

The  coke  trade. — Many  coals  when  deprived  of  their  impurities  will  coke  which  never 
coked  before,  and  the  quality  of  every  description  of  coke  may  be  greatly  improved.  In 
coals  above  the  average  in  (juality,  it  has  been  found  that  the  clinker  may  by  water  purifica- 
tion be  reduced  by  four-fifths  in  quantity.  The  two  principal  sources  of  clinker — the  wliit- 
ish  scales  of  carbonate  of  lime  and  the  iron  pyrites — are  removed.  A  coke  more  uniform 
in  texture  ami  better  in  appearance  is  produced,  and  different  descriptions  of  coal  may  be 
simultaneously  mixed  and  purified  by  this  macliine.  A  cost  of  3(/.  per  ton  on  the  coke  will 
remove  those  impurities  for  which  tlie  consumer  now  pays  at  the  .same  rate  as  the  coke  it- 
self. An  increase  in  the  make  and  quality  of  the  iron  results  from  using  purified  coke  in 
blast  fnniaccs. 

Persons  using  steam. — The  amount  of  ash  and  clinker  from  a  coal,  by  no  means  re- 
presents tlie  full  amount  of  loss  and  waste  occasioned  by  tlicm.  The  coal  is  imperfectly 
burnt,  and  the  fire  bars  are  injured.  By  removing  the  impurities,  much  of  tlie  laljor  in  at- 
tending boiler  fires  may  be  spared,  and  the  steam  kept  up  more  regularly.  In  steamers^ 
and  whenever  the  freight  of  coal  is  heavy,  these  advantages  are  peculiarly  important. 

_  Gas  companies. — Gas  may  be  produced  comparatively  free  from  sulphur,  as  well  as  a 
purer  and  more  valuable  coke.  By  a  small  addition  to  tlie  cost  of  the  machine  the  coal 
may  be  dehvered  in  a  dry  state. 

Siniliis  and  workers  in  metal. — A  coal  purer  than  the  large  coal  is  produced.  Better 
work  and  metal  and  cleaner  heartlis  are  the  results.  Smiths  are  paying  in  several  instances 
nearly  double  the  former  prices  for  coals  which  have  been  purified.  In  puddling  and  other 
furnaces  tlie  advantages  of  pure  coal  have  been  well  ascertained. 

Patent  fuel  companies. — In  all  cases  where  freights  are  heavy  and  the  manipulation  of 
the  fuel  costly,  purity  in  the  raw  material  is  cs.sential. 

CoUierii  owners. — Coal  and  shale  in  lieu  of  being  thrown  into  the  gob  can  be  brought 
out  of  the  mine  and  separated  for  from  Is.  to  2s.  per  ton,  including  haulage,  &c.  Crop 
coal,  old  pillars,  and  creeps  may  be  turned  to  account. 

Tlie  spontaneous  combustion  in  the  wastes  of  some  mines  may  be  iv.-cveiitod  l)y  l)ringing 
out  tlie  whole  of  the  small  coal  and  [lyiites  at  a  now  rcmunorative  price.  New  coal  scams 
may  be  brought  into  the  market,  to  the  l)enefit  both  of  tlie  jirodncer  and  consumer. 

In  working  this  machine  tlie  coal  tram  is  tipped  into  tlie  coal  lioppcr ;  it  is  tlience  con- 
veyed by  the  elevator  in  a  continuous  stream  into  the  machine,  and  tlie  purified  coal  is 
delivered  continuously  into  a  tram,  whilst  the  shale  and  pyrites  are  delivered  in  a  continu- 
ous manner  l>y  the  dredger,  or  Jacob's  ladder.  Tiie  workman  ha.s  oidy  to  attend  to  the 
jilacing  of  tiiese  wagons  and  regulating  the  aniount  of  opening  of  the  valves,  which  allow  the 
shale  to  descend  into  the  shale  box  after  it  is  separated. 
Vor,.  III.— r.8 


1074  WATER  PRESSURE  MACHINERY  FOR  MINES, 

The  revolving  hopper  allows  the  coal  to  descend  gradually  into  the  separator,  where  a 
plow  current  of  water  is  driven  upwards  thvough  the  mass  of  shale  and  coal,  at  a  velocity 
of  from  4  to  5  feet  per  minute,  by  tlie  agitator  or  screw.  Tliis  water  passes  back  again  by 
the  finely  perforated  plate,  and  with  the  fine  silt  suspended  in  it,  is  again  driven  upwards 
by  the  screw  to  undergo  a  repetition  of  tho  process.  The  gentle  agitation  produced  by  this 
current  separates  the  shale  and  pyrites  from  the  coal  in  the  separator,  the  two  latter  descend 
through  the  valves  and  are  talcen  up  by  the  dredger,  whilst  the  former  is  pushed  upwards 
out  of  the  water  by  the  curved  arm ;  and  as  soon  as  tlio  water  has  drainecl  off,  the  coal  falls 
on  to  tlie  shoot,  which  conducts  it  to  the  tram.  A  brush  following  the  arm  helps  to  keep 
the  holes  in  the  perforated  plate  open.  The  valves  remain  constantly  more  or  less  open, 
according  to  the  indications  given  by  the  dredger,  and  are  regulated  by  the  valve  lever. 
The  water  required  to  rei)lace  that  absorbed  by  the  dry  coal  and  shale  enters  by  the  hopper 
and  flows  .slightly  inwards  through  the  shale  valves  as  the  shale  is  coming  out. 

The  objects  said  to  be  attained  by  the  machine  are:  1st,  a  more  perfect  separation  of  the 
impurities  than  by  the  jigging  or  huddling  processes;  2d,  a  saving  of  from  5  to  15  per 
cent,  of  coal ;  3d,  economy  of  power  and  manual  labor ;  4th,  saving  of  water  and  the  de- 
livery of  the  coal  in  a  drier  state. 

Machines  have  been  established  in  Scotland,  Cumberland,  Derbyshire,  Gloucestershire, 
and  Wales,  to  purify  from  20  to  100  tons  of  coal  per  day,  at  a  cost  not  exceeding  3c/.  per 
ton,  and  with  a  loss  not  exceeding  2  per  cent,  of  coal. 

WATER  PRESSURE  MACHINERY  FOR  MIXES.  Con.siderable  attention  has  been 
given  to  the  construction  of  pressure  engines  by  Mr.  Darlington,  who  was  actively  engaged 
some  years  since  in  effecting  the  drainage  of  the  Alport  Mines,  in  Derbyshire.     Sec  fig.  C82. 

The  first  engine  erected  by  him  had  a  cylinder  50  inclies  diameter,  and  a  stroke  of  10 
feet ;  the  piston-rod  passed  tiirough  the  bottom  of  the  cylinder  and  formed  a  continuation 
with  the  pump-rod,  whilst  the  valve  and  cataract  gearing  was  worked  by  a  rod  connected 
with  the  top  of  the  piston,  which  gave  motion  to  a  beam  and  plug-rod  gearing.  The  column 
of  water  was  132  feet  high,  affording  a  pressure  on  the  piston  of  about  58  pounds  per 
square  inch,  or  more  than  50  tons  on  its  area.  The  water  was  raised  from  a  depth  of  22 
,  fathoms,  by  means  of  a  plunger  42  inches  diameter,  and  in  very  wet  seasons  it  discharged 
into  the  adit  nearly  5,ii00  gallons  of  water  per  minute.  Water  was  admitted  only  on  the 
under  side  of  the  piston,  and  in  order  to  avoid  violent  concussion  in  working  ;  two  sets  of 
valves  were  employed,  the  larger  being  cylindrieally  shaped,  22  inches  diameter;  and  the 
smaller  5  inches  diameter.  In  making  the  upstroke  of  the  engine  the  cylindrical  valves 
admitted  a  full  flow  of  water  for  about  |  of  the  stroke,  and  then  commenced  closing,  but 
at  this  stage  the  small  valve  opened,  through  which  passed  sufficient  water  to  terminate  the 
stroke.  In  this  way  the  flow  of  water  in  the  column  was  gradually  slackened,  and  finally 
brought  to  a  state  of  rest  without  imparting  impact  to  the  machinery.  The  speed  of  the 
engine  was 'regulated  by  sluice  valves,  one  fixed  between  the  engine  and  the  pressure 
column,  and  the  other  upon  the  discharge-pipe. 

The  cylindrical  valves  were  made  of  brass  with  a  thin  feather-edged  beat,  and  kept  tight 
by  a  concentric  l-ioss,  projecting  from  the  nozzle,  upon  which  hemp  packing  was  laid.  This 
was  pressed  down  by  a  projection  in  the  under  surface  of  the  valve  bonnet.  The  water 
thus  acted  on  the  exterior  of  the  valves  between  the  zone  of  packing  and  the  seatings,  and 
when  opened  pa.ssed  through  the  latter.  Besides  this  engine,  others  of  a  different  construc- 
tion were  designed  and  erected  by  Mr.  Darlington,  but  the  one  to  which  he  gave  preference 
for  simplicity,  cheapness,  and  smoothness  of  action,  is  illustrated  in  the  following  woodcut. 

This  engine  has  one  main  cylinder  a,  resting  on  strong  cast-iron  beareis  b  b,  fixed 
across  the  shaft.  The  piston-rod  c  is  a  continuation  of  the  pump-rod  s,  and  works  through 
the  cylinder  bottom  d.  In  front  of  the  cylinder  a,  is  a  smaller  one,  e,  with  differential  diam- 
eters for  the  admission  and  emission  of  water,  and  right  and  left  are  sluice  valves  not 
shown  for  regulating  the  speed  of  the  engine.  Connected  with  the  second  cylinder  is  a 
small  3-inch  auxiliary  cylinder,  f,  provided  with  inlet  and  outlet  regulating  cocks. 

In  starting  this  engine  the  sluice  valves  and  regulating  cocks  are  opened,  the  water  then 
flow  from  the  pressure  column  o,  into  the  main  cylinder  a,  through  the  nozzle  cylinder  e, 
and  acts  under  the  piston  ir,  until  the  upstroke  is  completed.  The  piston  i  hasa  counter 
j)iston  K,  of  larger  diameter,  and  when  relieved  from  pressure  on  its  upper  surface,  the 
water  acting  between  them  forces  it  upwards,  in  which  case  the  pressure  is  cut  off  from  the 
ruain  piston,  and  the  water  contained  in  the  cylinder  a  is  free  to  escape  under  the  piston  i, 
through  the  holes  l.  With  the  emission  of  watc^r  from  the  main  cylinder  through  m,  the 
downstroke  is  effected.  The  downward  displacement  of  the  pistons  i  and  k  is  performed 
by  the  auxiliary  cylinder  f,  and  pistons  n,  o  ;  the  pressure  column  is  continually  acting  be- 
tween these  pistons,  and  by  their  alternate  displacement  by  the  fall-bob  p,  and  canti-arbor  q. 
The  water  is  either  admitted  or  prevented  from  operating  on  the  upper  surface  of  tlic  piston 
K.  The  water  from  the  top  of  piston  k  escapes  through  the  aperture  R.  The  motion  of  the 
canti-arbor  q  is  effected  by  tappets  fixed  on  the  pump-rod  s. 

One  of  these  engines  was  recently  in  operation  at  the  Miucra  Mines,  in  North  Wales. 


WATER  PRESSURE  MAOHIKERY  FOR  MINES. 


1075 


The  cvlinder  was  35  inches  diameter ;  stroke  10  feet,  pressure-column  227  feet  high.     Its 
average  speed  was  80  feet   and  maximum  speed  140  feet  per  minute.     The  pressure  of 


6S2 


M 


*? 


1076 


WATER  PRESSURE  MACHINERY  FOR  MINES. 


water  under  the  piston  was  98  pounds  per  square  inch,  giving  a  total  weight  on  its  area  of 
about  40  tons.  This  macliine  required  no  personal  attendance,  the  motion  being  certain 
and  continuous,  as  long  as  the  working  parts  remained  in  order  ;  consequently  the  cost  of 
maintaining  it  was  of  the  most  trifling  character. 

In  1803,  Trevithick  erected  an  engine  at  the  Alport  Mines  which  worked  continuously 
for  a  period  of  forty-seven  years,  or  until  1850,  when  the  mines  ceased  working.  The  water 
from  tlie  i)ressure-column  acted  on  alternate  sides  of  the  main  piston,  by  means  of  two  pis- 
ton valves,  displaced  by  a  heavy  tumbling  beam,  and  tilted  by  a  projection  from  the  pump- 
rod.  The  construction  and  action  of  this  machine  will  be  best  understood  by  the  accom- 
panying illustration,  jig.  083. 

A,  main  cylinder ;  b  and  c,  valve  pis- 
tons ;  D,  chain  wheel,  upon  the  axis  of 
which  is  fixed  a  lever  not  shown,  in  con- 
nection with  a  tumbling  beam  ;  e,  aper- 
ture through  which  water  enters  from 
pressure-column  ;  f,  pipe  in  communica- 
tion with  main  cylinder  a,  and  g,  pipe  for 
discharging  the  water  admitted  both  above 
and  under  the  main  piston  h.  The  posi- 
tion of  the  valve  pistons  in  the  woodcut 
shows  that  the  pressure-column  is  sup- 
posed to  be  flowing  through  the  holes  i, 
upon  the  piston  h,  producing  a  down 
stroke,  and  that  the  water  which  has  been 
introduced  under  this  piston  in  order  to 
make  the  up-stroke  is  leaving  through 
the  pipe  f,  holes  k,  and  outlet  jupe  g. 

By  referring  to  HYiiUArLic  Cranks, 
the  principles  adopted  by  Sir  Wm.  Arm- 
strong will  be  understood. 

It  is  not  necessary  to  repeat  that  part 
of  the  subject  in  this  place,  but  it  re- 
mains to  notice  the  applications  made  of 
the  pressure  derived  from  natural  falls. 

When  the  moving  pcn'er  consists  of  a 
natural  column  of  water,  the  pressure 
rarely  exceeds  250  or  SOO  feet ;  and  in 
such  cases  he  has  employed  to  produce 
rotary  motion,  in  preference  to  the  origi- 
nal scheme  of  a  rotary  engine,  a  pair  of 
cylinders  and  pistons,  with  slide  valves 
resembling  in  some  degree  those  of  a 
high-pressure  engine,  but  having  relief 
valves  to  prevent  shock  at  the  return  of 
the  stroke,  as  shown  in  f(j.  330,  already 
described.  Where  the  engine  is  single- 
acting,  with  plungers  instead  of  pistons, 
as  in  the  water-pressure  engines  already 
described,  the  relief  valves  are  greatly 
simplified,  and  in  fact  are  reduced  to  a 
single  clack  in  connection  with  each 
cylinder,  opening  against  the  pressure, 
which  is  the  same  as  the  relief  valve  in  the  valve  chest  of  the  hydraulic  crane.  The  water- 
pressure  engines  erected  at  Mr.  Beaumont's  lead  mines,  at  Allenheads  in  Northumberland, 
present  examples  of  such  engines  applied  to  natural  falls.  They  were  there  introduced  under 
the  advice  of  Mr.  Sopwith,  and  are  now  used  for  the  various  purposes  of  crushing  ore,  raising 
materials  from  the  mines,  pumping  water,  giving  motion  to  machinery  for  washing  and  sep- 
arating ore,  and  driving  a  saw-mill  and  the  machinery  of  a  workshop.  In  all  these  cases 
nature,  assisted  by  art,  has  provided  the  power.  Small  streams  of  water,  which  flowed 
down  the  steep  slopes  of  the  adjoining  hills,  have  been  collected  into  reservoirs  at  eleva- 
tions of  about  200  feet,  and  pipes  have  been  laid  from  these  to  the  engines. 

Another  application  of  hydraulic  machinery  at  the  same  mines  is  now  being  made  in 
situations  where  falls  of  sufficient  altitude  for  working  such  engines  cannot  be  obtained, 
which  from  its  novelty  deserves  special  notice.  For  the  purpose  of  draining  an  extensive 
mining  district  and  searching  for  new  veins,  a  drift  or  level  nearly  six  miles  in  length  is  now 
being  executed.  This  drift  runs  beneath  the  valley  of  the  Allen  nearly  in  the  line  of  that  ' 
river,  and  upon  its  course  three  mining  establishments  are  being  formed.     At  each  of  these 


WATER,  SEA. 


107T 


power  is  required  for  the  various  purposes  above  mentioned,  and  it  was  desired  to  obtain 
this  power  without  resorting  to  steam  engines.  The  river  Allen  was  the  only  resource,  but 
its  descent  was  not  sufficiently  rapid  to  permit  of  its  being  advantageously  applied  to  water- 
pressure  engines.  On  the  other  hand,  it  abounded  with  falls  suitable  for  overshot  wheels, 
but  these  could  not  be  applied  to  the  purposes  required  without  provision  for  conveying  the 
power  to  many  separate  places.  Under  these  circumstances  it  was  determined  to  employ 
the  stream  through  the  medium  of  overshot  wheels  in  forcing  water  into  accumulators,  and 
thus  generating  a  power  capable  of  being  transmitted  by  pipes  to  the  numerous  points  where 
its  agency  was  required.  In  this  arrangement  intensity  of  pressure  takes  the  place  of  ujug- 
nitude  of  volume,  and  tiie  power  derived  from  the  stream  assumes  a  ibrm  susceptible  if 
unlimited  distribution  and  division,  and  capable  of  being  utilized  by  small  and  compact 
machines. 

A  somewhat  similar  plan  is  also  adopted  at  Portland  Harbor,  in  connection  with  the 
coaHng  establishment  there  forming  for  the  use  of  the  navy.  The  object  in  that  case  is  to 
provide  power  for  working  liydraulic  cranes  and  hauling  machines,  and  more  particularly  for 
giving  motion  to  machinery  arranged  by  Mr.  Coode,  the  present  engineer  of  the  work,  for 
putting  coal  into  war  steamers.  A  reservoir  on  the  adjoining  height  alfords  an  available 
head  of  upwards  of  300  feet ;  but  in  order  to  diminisli  the  size  of  the  pipes,  cylinders,  and 
valves  connected  with  the  hydraulic  machinery,  and  also  with  a  view  of  obtaining  greater 
rapidity  of  action,  a  hydraulic  pumping  engine  and  accumulator  are  interposed,  for  the  pur- 
pose of  intensifying  tiie  pressure  and  diminishing  the  volume  of  water  acting  as  the  medium 
of  transmission. 

WATER,  SEA — rendered  fresh.  {Commimicated  bi/  Dr.  Normandif.)  The  analyses 
of  sea  water  which  have  been  made  at  various  times,  and  the  results  of  which  will  be  found 
elsewhere,  prove  that  that  liquid  contains  from  3i-  to  4  per  cent,  of  saline  substances,  two- 
thirds  at  least  of  which  are  common  salt,  and  also  a  certain  quantity  of  organic  matters,  all 
of  which  substances  impart  to  it  its  well-known  taste  and  odor,  and  render  it  unfit  for  drink- 
ing or  other  domestic  purposes. 

To  render  sea  water  drinkable,  and  thus  avoid  the  accidents  resulting  from  an  insuffi- 
cient supply,  or  from  an  absolute  want  of  fresh  v/ater,  in  sea  voyages,  is  a  problem  which 
may  be  said  to  have  engaged  the  attention  of  men  from  the  very  moment  they  ventured  to 
lose  sight  of  the  friendly  shore  and  became  navigators ;  gradually,  as  the  enlargement  of 
commercial  operations  extended  the  length  of  sea  voyages,  the  difficulty  of  preserving  in  a 
pure  state  the  fresh  water  taken  in  store,  the  necessity  of  putting  up  at  stations  for  procur- 
ing a  fresh  supply  of  it  when  it  is  exhausted,  the  great  gain  to  bo  realized  by  being  enabled 
to  devote  to  the  stowage  of  cargo  the  valuable  space  occupied  by  water-tanks  and  water- 
casks,  have  induced  many  people  at  various  times,  and  for  many  years  past,  to  contrive  appa- 
ratus by  means  of  which  sea  water  would  be  rendered  fit  to  drink,  or  by  means  of  which 
good  fresh  water  could  be  obtained  therefrom. 

Fresh  water  can  be  obtained  from  sea  water  in  two  ways ;  the  one 
by  distillation,  the  other  by  passing  it  through  a  layer  or  column  of 
sand,  or  of  earth,  of  sufficient  thickness  or  length.  Tn  effect,  if  sea 
water  be  poured  at  a,  in  a  pipe  15  feet  high,  and  full  of  clean  dry  sand, 
the  water,  which  will  at  first  flow  at  b,  will  be  found  pretty  fresh  and 
drinkable,  but  as  the  operation  is  continued,  the  water  which  flows  at 
B  soon  becomes  brackish ;  the  brackishness  gradually  augmenting, 
until,  in  a  very  short  time,  the  water  which  flows  at  b  is  actually  more 
salted  than  that  poured  at  a  ;  because  the  latter  dissolves  the  salt 
which  had  been  first  retained  by  the  sand,  which  must  then  be  re- 
newed, or  washed  with  fresh  water,  a  process  evidently  useless  for  the 
purpose  in  question.  This  phenomenon,  according  to  Berzelius,  is 
due  to  the  interstices  between  the  grains  of  sand  acting  as  capillary 
tubes;  and  as,  at  the  beginning  of  the  operation,  the  effect  depends 
more  on  the.  attraction  than  on  the  pressure  of  the  liquid  poured  in 
one  of  the  branches  of  the  tube,  the  salt  is  partly  separated  from  the 
■water  which  held  it  in  solution,  the  latter  lodging  itself  into  the  inter- 
stices of  the  sand,  and  filling  them ;  if,  when  the  mass  of  the  sand  is 
completely  wetted,  a  greater  quantity  of  sea  water  is  poured  upon  it, 
the  weight  of  the  said  sea  water  first  displaces  and  expels  the  fresh 
water ;  but  as  soon  as  the  interstices  of  the  sand  have  thus  been  forci- 
bly filled  up  witli  sea  water,  the  water  flowmg  at  b  becomes  more  and 
more  salted;  wherefore  this  filtration  cannot  yield  more  fresh  water 
than  can  be  contained  in  the  interstices  of  a  column  of  sand  of  a  cer- 
tain length  and  proportionate  to  the  saltness  of  the  sea  water. 

Howbeit,  the  removal  of  the  salt  from  sea  water,  so  as  to  obtain 
fresh  water  therefrom,  is,  practically  speaking,  an  impossibility,  except  by  evaporation. 

At  first  sight  one  would  think  that  it  is  sufficient  to  submit  sea  water  to  distillation  to 


684 


1U78  WATER,  SEA. 

convert  it  into  fresh  water,  and  that  the  solution  of  the  problem  is  altogether  dependent 
upon  a  still  constructed  so  as  to  produce,  by  evaporation,  a  great  quantity  of  distilled  water, 
with  a  consumption  of  fuel  sufficiently  small  to  become  practicable. 

Distillation  at  a  cheap  rate  is  doubtless  an  important  item,  and  fuel  being  a  cumbrous 
and  expensive  article  on  board  ship,  it  is  superabundantly  evident  that,  supposing  all  the 
apparatus  which  have  hitherto  been  contrived  for  the  purpose  to  answer  equally  well,  that 
one  would  clearly  merit  the  preference  which  would  produce  most  at  least  cost ;  but  there 
are,  besides,  other  desiderata  of  a  no  less  primary  importance,  and  it  is  from  having  neglect- 
ed, ignored,  or  been  unable  to  realize  them,  tliat  all  the  apparatus  for  obtaining  fresh  water 
from  sea  water,  which  have  been  from  time  to  time  brought  before  the  public,  have  hitherto, 
without  exception,  proved  total  failures,  or,  after  trial,  have  been  quite  discarded,  or  fulfil 
the  object  in  view  in  a  way  so  imperfect  or  precarious,  that,  practically  speaking,  the  man- 
ufacture of  fresh  water  at  sea,  or  from  sea  water,  may  be  said  to  have  been,  until  quite  lately, 
an  unaccomplished  feat.  In  order  to  understand  the  nature  of  the  difficulties  which  stood 
in  the  way  of  success,  a  few  words  of  explanation  become  necessary. 

When  ordinary  water,  whether  fresh  or  salt,  is  submitted  to  distillation,  the  condensed 
steam,  instead  of  being,  as  might  be  supposed,  pure,  tasteless,  and  odorless,  yields  on  the 
contrary  a  liquid  free  from  salt,  it  is  true,  but  of  an  intolerably  nauseous  and  empyreumatic 
taste  and  odor,  which  it  retains  for  many  weeks;  it  is,  moreover,  insipid,  flat,  and  vapid, 
owing  to  its  want  of  oxygen  and  carbonic  acid,  which  water  in  its  natural  state  possesses, 
and  of  which  it  has  been  deprived  by  the  process  of  distillation.  In  the  absence  of  ordinary 
fresh  water,  this  distilled  water,  however  disagreeable  and  objectionable  it  may  be,  is  of 
course  of  use  so  far  as  it  is  fresh,  but  the  crews  invariably  refuse  it  as  long  as  they  can  ob- 
tain a  supply  from  natural  sources,  even  though  this  may  be  of  so  bad  a  quality  as  to  endan- 
ger their  health  or  their  lives,  as  evidenced  by  the  report  of  The  Times'  Own  Correspondent 
in  reference  to  the  water  supplied  to  the  crews  of  our  ships  in  the  Baltic  during  the  Crime- 
an war. 

With  a  view  to  remedy  the  defects  just  alluded  to,  various  means  have  from  time  to 
time  been  proposed  and  employed ;  such  as  the  addition  of  alum,  sulphuric  and  other  acids, 
chloride  of  lime,  &c. ;  but  it  is  evident  that  chemical  reagents  cannot  effect  the  object ;  but 
if  even  they  did,  their  use  is  always  unsafe,  for  their  continuous  and  daily  absorption  might, 
and  doubtless  would,  cause  accidents  of  a  more  or  less  serious  nature,  not  to  speak  of  the 
trouble  and  care  i-equired  in  making  such  additions.  Liebig  said  with  both  authority  and 
reason,  that,  as  a  general  rule,  the  use  of  chemicals  should  never  be  recommended  for  culi- 
nary (or  food)  purposes,  fopchemicals  are  seldom  met  with  in  commerce  in  a  state  of  purity, 
and  are  frequently  contaminated  by  poisonous  substances.  On  the  other  hand,  the  percola- 
tion through  perforated  barrels  or  coarse  sieves,  porous  substances,  plaster,  chalk,  sand,  &c., 
the  pumps,  ventilators,  bellows,  agitators,  which  have  been  proposed  to  aerate  the  distilled 
water  obtained,  and  render  it  palatable,  are  slow  in  their  action,  of  a  difficult,  inconvenient, 
or  impossible  application ;  and  as  to  leaving  the  distilled  water  to  become  aerated  by  the 
agitation  imparted  to  it  in  tanks  or  casks  by  the  motion  of  the  ship,  this  must  be  continued 
for  a  length  of  time,  proportioned  of  course  to  the  vigor  of  the  oscillations  imparted  to  the 
ship  )iy  the  violence  of  the  waves,  and  the  time  tluis  required  is  always  considerable ;  yet 
in  this  way,  and  finally  by  pouring  the  water  several  times  from  one  glass  to  another  before 
drinking  it,  it  may  become  fully  aerated,  but  without  entirely  losing  its  vapid  and  nauseous 
taste  and  odor,  and  in  fact  the  report  of  the  correspondent  of  TJlb  Times,  above  alluded  to, 
shows  that  this  method  is  attended  with  but  indifferent  success.  I  shall  presently  explain 
why  no  system  or  method  of  aeration  whatever  could  be  attended  with  success,  in  the  pro- 
duction oi perfect  fresh  water  from  salt  water,  notwithstanding  the  great  ingenuity  displayed 
in  their  endeavors  to  realize  the  object  in  view  l)y  persons  who,  some  of  them  at  least, 
though  of  consummate  skill  as  engineers  or  philosophers,  or  as  men  of  general  knowledge, 
were  not,  it  would  appear,  sufficiently  well  acquainted  with  the  exact  nature  of  the  difficul- 
ties which  stood  in  the  way,  or  were  not  fitted  for  the  investigation  and  conquest  thereof. 
In  reality  the  failures  in  this  respect  have  been  due  to  the  fact  that  the  aeration  of  the  dis- 
tilled water,  instead  of  being,  as  everybody  thought,  the  whole  problem,  is  only  a  part  of  it ; 
and  we  shall  see,  moreover,  that  the  said  aeration,  to  be  effective,  must  be  practised  under 
certain  conditions,  in  a  certain  manner,  and  is  oidy  a  preparatory  step,  though  an  all-impor- 
tant one,  to  the  final  production  o^  perfect  fresh  water. 

But  before  proceeding  further,  it  may  not  be  amiss  to  say  a  few  words  respecting  another 
condition  in  the  construction  of  marine  condensing  machines,  which,  from  not  being  suffi- 
ciently taken  into  account,  frequently  puts  them  suddenly  out  of  service,  or  necessitates  con- 
stant repairs.  I  am  alluding  to  those  condensers  the  joints  of  which  arc  made  by  soldering 
or  brazing ;  for  the  different  rates  of  expansion  and  contraction  of  metals  by  heat  and  by 
cold,  during  tlie  intervals  of  work  and  of  rest  of  the  apparatus,  would  be  sure  eventually  to 
cause  the  soldered  jiarts  to  crack  and  give  way,  an  clTect  which  the  motion  of  the  ship  would 
of  course  greatly  promote.  This  in  f  ict  was  the  cause  of  the  accident  which  about  thirty- 
five  years  ago  put  the  lives  of  Captain  Freycinet  and  of  his  crew  in  fearful  jeopardy.     On 


WATER,  SEA. 


1079 


the  other  hand,  the  electro-chemical  action  which  sets  up  between  the  metals  of  the  solder 
and  that  of  the  condenser,  corrodes  the  latter,  and  iu  either  case  a  leak  being  started,  the 
sea  water  penetrates  through  it  into  the  apparatus,  which  may  thus  be  at  ouce  put  out  of 
service  after  a  few  months'  working,  its  unsoundness  thus  creating  the  most  distressing  suf- 
ferings, and  putting  the  lives  of  all  on  board  in  imminent  peril.  It  may  therefore  be  most 
truly  asserted  that  any  fresh-water  distilling  apparatus,  for  marine  puri)oses,  in  any  part  of 
which  solder  is  employed,  is  ipso  facto  defective,  and  ought  not  to  be  trusted,  the  soldered 
parts  being  sure  to  give  way  from  the  causes  just  alluded  to.  Lastly,  another  condition  often 
lost  sight  of  (although  of  extreme  importance,)  iu  the  endeavors  which  have  been  made 
to  accomplish  the  object  in  question,  is  to  obviate  or  prevent  the  deposit  of  saline  matter 
which  takes  place  when  the  limit  of  saturation  has  been  attained,  and  wliich  in  a  short  time 
interferes,  temporarily  at  least,  and  often  permanently,  with  the  working  of  the  apparatus, 
renders  frequent  repairs  necessary,  and  iu  all  cases  eventually  destroys  it. 

The  question  which  had  been  hitherto  left  unanswered,  and  yet  which  must  be  integrally 
solved  before  success  could  be  hoped  for,  is  the  following : — 

To  obtain,  with  a  smarll  proportion  of  fuel,  large  quantities  of  fresh,  inodorous,  salubri- 
ous aerated  water,  without  the  help  of  chemical  reagents,  by  means  of  a  self  acting  and 
compact  apparatus,  capable  of  being  worked  at  all  hours,  under  all  latit^ies,  in  all*  weathers 
and  conditions  compatible  with  the  existence  of  the  ship  itself,  and  incapable  of  becoming 
incrusted,  or  of  otherwise  going  out  of  order. 

How  this  complex  and  difficult  problem  has  been  solved  I  will  now  proceed  to  explain : — 

It  is  a  kuown  property  of  steam  that  it  becomes  condensed  into  water  again,  when- 
ever it  comes  in  contact  with  water  at  a  temperature  lower  than  itself,  no  matter  how  high 
the  temperature  of  that  condensing  water  may  be. 

It  is  known  that  the  sea  and  other  natural  waters  are  saturated  with  air  containing  a 
larger  proportion  of  oxygen  and  of  carbonic  acid  than  the  air  we  breathe.  In  effect,  100 
volumes  of  the  air  held  in  solution  in  water  contain  from  32  to  33  volumes  of  oxygen, 
whereas  100  volumes  of  ordinary  atmospheric  air  contain  only  2-i  volumes  of  oxygen. 
Again,  ordinary  atmospheric  air  contains  only  ',4000  of  carbonic  acid,  whereas  the  air  held  in 
solution  in  water  contains  from  40  to  42  per  cent,  of  carbonic  acid.  The  experiments  which 
I  undertook  iu  1849-50,  with  a  view  to  determine  the  amount  of  these  gases  present  in  water, 
showed  me  that  this  amount  varied  with  the  state  of  purity  of  the  water ,  that,  whilst  ordinary 
rain  water  contains,  on  an  average,  15  cubic  inches  of  oxygenized  air  per  gallon,  constituted 
as  follows: —  * 

Carbonic  acid -         6-26 

Oxygen  -         - 5'04 

Nitrogen 3-70 


15-00 
sea  water,  owing  to  the  various  substances  which  it  holds  in  solution,  contains  only  on  an 
average  5  cubic  inches  of  gases,  more  than  one  half  of  which  is  carbonic  acid ;  or,  in  other 
words,  1  gallon  of  sea  water  contains  about  two  thirds  less  gases  than  ordinary  rain  water, 
and  one  half  less  gases  than  river  water. 

I  have  also  ascertained  that  air  begins  to  be  expelled  from  such  natural  waters  when  the 
temperature  reaches  about  130°  Fahr. ;  and  we  know  that  when  the  temperature  reaches 
212'  Fahr.,  all  the  air  which  it  contained  has  been  expelled,  and  it  is  for  this  reason  that 
distilled  water  contains  no  air. 

At  that  time  I  shared  the  prevalent  opinions  of  all  who  had  interested  themselves  on  the 
subject,  namely,  that  the  flat,  disagreeable,  and  mawkish  taste  and  odor  of  distilled  water  were 
due  to  its  having  been  deprived  of  air;  and  knowing  that  the  various  methods  adopted  or 
resorted  to  for  aerating  distilled  water  by  forcing  atmospheric  air  into  it  had  failed,  and 
that  the  distilled  water  thus  aerated  spontaneously  or  by  mechanical  means,  retained  the 
abominable  taste  and  odor  just  alluded  to,  and  remained  for  a  long  time  almost  undrinkable, 
I  thought  that  the  defect  was  possibly  owing  to  the  air  mixed  with  it  not  being  of  a  suitable 
quality,  the  experiments  which  I  have  related  having  indeed  shown  that  the  composition 
of  air  contained  mrturally  in  water  differed  essentially  from  atmospheric  air;  and  that  con- 
sequently if  I  could  reintroduce  into  the  distilled  water  the  carbonic  acid  and  oxygen  of 
which  ebullition  had  deprivecl  it,  it  would  then  become  as  sweet  as  good  ordinary  water. 
With  this  view  I  contrived  the  apparatus  which  forms  the  subject  of  the  present  article. 

The  apparatus  is  represented  infirjs.  083,  C86.  It  consists  of  three  principal  i)arts,  an 
evaporator,  14,  a  condenser,  G,  antl  a  refrigerator,  3,  joined  so  as  to  form  one  compact  and 
solid  mass,  screwed  and  bolted,  without  soldering  or  brazing  of  any  kind.  The  evaporator 
is  a  cylinder,  partly  filled  with  sea  water,  into  which  a  sheaf  of  pii)es  are  immersed,  so  that 
on  admitting  steam  at  a  certain  pressure  into  these  pipes  it  is  condensed  into  fre.-^h,  though 
non-aerated  water  by  the  sea  water  by  which  the  pipes  are  surrounded,  that  sea  water  being 
thus  heated  and  a  portion  of  it  evaporated  at  the  same  time ;  for  it  is  one  of  the  properties 
of  steam  to  be  condensed  by  water,  no  matter  how  high  the  temperature  of  thnt  v.-ater  may 


1080 


WATER,  SEA. 


be,  if  it  be  only  inferior  to  that  of  the  steam.  This  non-aerated  water  becomes  aerated,  a\ 
I  shall  explain  presently.  On  board  steamers,  the  steam  is  obtained  directly  from  the  boil- 
ers of  the  ship  ;  in  sailing  vessels  it  is  procured  from  a  small  boiler  which  may,  or  may  not 
be  connected  with  the  hearth,  galley,  or  caboose. 

The  steam  at  a  pressure  being,  of  couvtie,  hotter  than  ordinary  boiling  water,  serves  to 
convert  a  portion  of  the  water  contained  in  the  evaporator  into  ordinary  or  no-pressure 
steam,  which,  as  it  reaches  the  pipes  in  the  condenser  6,  is  resolved  therein  into  fresh  aer- 
ated water.  The  manner  in  which  it  becomes  aerated  will  be  exi)lained  presently.  By 
thus  evaporating  water  under  slight  pressure,  one  fire  performs  double  duty,  and  tlms  the 
first  condition,  that  of  economy,  is  completely  fulfilled;  ibr  while,  in  the  usual  way,  1  lb.  of 
coal  evaporates  at  most  G  or  7  lbs.  of  water,  the  same  quantity  of  coals,  burnt  under  the 
same  boiler,  but  in  connection  with  my  apparatus,  is  thus  made  to  evaporate  12  or  14  lbs. 
of  water ;  or,  in  other  words,  from  the  same  amount  of  coals  or  of  steam  employed,  the  ma- 
chine which  I  am  describing  will  produce  double  the  quantity  of  fresh  water  that  can  be 
obtained  by  simple  or  ordinary  distillation ;  that  is  to  say,  double  the  quantity  obtained  by 
the  ordinary  condensers. 

The  comparative  trials  made  in  18.59  on  board  II.  M.  ships  the  S{)hynx,  Erebus,  and 
Odin,  at  Portsmouth,  before  the  Commissioners  of  the  Admiralty,  have  most  conclusively 
proved  the  [jcrfcct  accuracy  of  that  statement. 

The  steam  issuing  from  the  evaporator,  and  which  is  condensed  by  the  water  in  the  con- 
denser, imparts,  of  course,  its  heat  to  the  sea  water  in  it ;  and  as  this  water  is  admitted  cold 
at  the  bottom,  whilst  the  steam  of  the  evaporator  is  admitted  at  the  top  of  the  condenser, 
the  water  therein  becomes  hotter  and  hotter  gradually  as  it  ascends,  and  when  it  finally 
reaches  the  top  its  temperature  is  about  208°  Fahr. 

I  have  already  stated  that  water  begins  to  part  with  its  air  at  a  temperature  of  about 
130'  Fahr. ;  therefore  the  greater  portion  of  the  air  contained  in  the  water  which  flows 
constantly  and  uninterruptedly  through  the  condenser  is  thus  separated,  and  led  thiough  a 
pipe  into  the  empty  space  left  for  steam  room  within  the  evaporator,  where  it  mixes  with 
the  steam. 

Now,  as  about  six  gallons  of  sea  water  must  bo  discharged  for  every  gallon  of  fresh 
water  which  is  condensed,  and  as  each  gallon  of  sea  water  contains,  as  we  said  before,  5 
cubic  inches  of  air,  and  whereas  the  utmost  quantity  of  it  that  fresh  water  can  natuially 
absorb  is  15  cubic  inches  per  gallon,  it  follows  that  the  steam  in  the  evaporator,  before  it  is 
finally  condensOT,  has  been  in  contact  with  twice  as  much  air  as  water  can  take  up,  the 
result  being  a  production  of  fresh  water  to  the  maximum  of  aeration,  that  is,  containing  as 
much  air  as  in  pure  rain  water. 

This  aeration  of  the  water  to  the  maximum  and  with  the  air  naturally  contained  in  the 
water  in  its  original  state,  though  a  condition  of  the  utmost  importance,  as  will  be  seen 
presently,  having,  to  my  extreme  surprise,  failed  in  removing  the  detestable  odor  and  taste 
in  question,  it  I)ccame  necessary  to  try  to  discover  whence  came  that  flavor  which  no  means 
of  aeration  could  destroy,  except  after  a  considerable  length  of  time,  and  even  tlien  never 
perfectly.  With  that  view  I  took  25  gallons  of  distilled  water,  possessing  the  characteristic 
empyreumatic  odor  and  taste,  and  having  evaporated  them  slowly  at  a  temperature  much 
below  the  boiling  point,  I  found,  at  the  end  of  six  weeks,  the  inside  of  the  little  platinum 
dish  into  which  the  experiment  had  finally  been  carried,  covered  with  a  thin  oily  film  of  a 
most  disagreeable  odor,  and  upon  rinsing  the  little  dish  in  25  gallons  of  excellent  ordinary 
fresh  water,  the  latter  immediately  aci|uired  the  empyreumatic  odor  and  flavor  peculiar  to 
distilled  water,  which  odor  and  flavor  are  evidently  due  to  the  destructive  action  of  the  heat- 
ed surface  of  the  vessels  in  which  the  water  is  boiled  on  the  organic  substances  which  are 
always  floating  in  the  air,  or  those  indescriliable  particles  of  dust  which  are  seen  playing 
or  moving  about  in  a  sunbeam,  and  which  have  been  dissolved  or  taken  up  by  the  water 
before  its  distillation.  That  water  has  the  power  of  absorbing  and  dissolving  organic  matter 
in  this  way  is,  of  course,  well  known;  but  it  may  be  illustrated  in  a  veiy  simple  manner,  as 
follows  : — If  water,  from  whatever  source,  be  distilled,  the  distillate  will,  of  course,  be  fresh 
water,  pure  fresh  water,  but  it  will  have  a  peculiar,  nauseous,  and  empyreumatic  taste  and 
odor,  stronger  in  proportion  as  the  heat  ajjplied  to  evaporate  it  has  been  more  elevated  ;  it 
is  that  smell  and  taste  wliich  render  it  undrinkable  for  a  while.  If,  wb.cn  it  has  become 
sweet  again  liy  long  standing,  which  period  may  be  hastened  by  agitation  in  the  atmos- 
jihere ;  if,  I  repeat  it,  that  distilled  water  be  then  redistilled,  the  di.stillate  will  lie  fouml 
to  have  acquired  again  the  same  empyreumatic  taste  and  odor  as  when  it  was  first  distilled. 
How  is  this?  Because  it  will,  by  standing  or  agitation,  have  redissolved  a  portion  of  the 
air  in  the  room  in  which  it  was  kept,  and  along  with  that  air  it  will  have  absorbed  whatever 
substances  were  present,  dissolved  or  susjiended  in  it,  and  those  substances  by  their  contact 
with  the  heated  surfaces  of  the  still,  yield  an  empyreumatic  product,  which  taints  the  distil'.iite. 
On  board  ships,  the  water  which  is  stored  in  lor  the  use  of  crews  in  the  usual  way,  in  the 
course  of  about  a  fortnight  becomes  putrid  and  almost  undrinkable,  because  the  organic 
matter  which  that  water  contains  is  undergoing  putrefactive  fermentation.  But  about  a  month 
or  so  afterward  the  water  gra<lual]y  liecomes  sweeter  and  sweeter,  until  at  last  it  becomes 


WATER,  SEA.  1081 

drinkable  again ;  because,  eventually,  all  the  organic  matter  which  it  contained  becomes 
decomposed,  carbonic  acid  and  water  being  the  result,  and  although  the  air  of  the  ship's 
hold  is  none  of  the  sweetest,  such  water,  as  just  said,  generally  remains  afterward  perfectly 
good  and  palatable  ;  because,  the  tanks  in  which  it  is  kept  being  covered  up,  it  is  sheltered 
from  fresh  pollutions,  and  because  it  is  now  saturated  with  pure  air,  and  therefore  cannot 
absorb  that  of  the  atmosphere. 

When  the  natural  waters  supplied  to  our  habitations  are  obtained  from  impure  sources, 
as  is  unfortunately  too  often  the  case,  the  evils  resulting  from  their  use  may  in  some  degree 
ba  remedied  by  putting  in  practice  the  recommendation  wliich  has  been  sometimes  made, 
of  boiling  such  water  previous  to  employing  it  as  a  beverage  ;  unfortunately  the  water,  being 
thereby  deprived  of  air,  is,  like  distilled  water,  though  in  a  less  degree,  unpalatable,  and 
vapid  and  heavy ;  it  is,  in  fact,  of  difficult  digestion ;  but  there  is  something  worse  than 
that :  water  which  has  been  boiled,  or  which  has  been  distilled,  by  reason  of  "its  containing 
no  air,  has  a  great  tendency  to  absorb  or  to  take  that  of  the  media  where  it  is  kept,  so  that 
if  distilled  water  which  contains  no  air  be  kept  in  a  ship's  hold,  or  in  an  impure  and  confin- 
ed place,  it  will  absorb  precisely  the  quantity  of  air  which  it  can  absorb,  namely,  15  cubic 
inches  per  gallon,  and  if  that  air  be  loaded  with  organic  particles  or  impure  emanations,  it 
will  spon  become  fetid  and  putrid.  The  experiments  of  Dr.  Angus  Smith  have  proved 
that  if  a  stream  of  air  wliich  has  already  been  breathed  be  passed  through  water,  the  latter 
will  retain  a  peculiar  albuminoid  matter  which  undergoes  putrefaction  with  extraordinary 
rapidity  ;  and  the  water  which  condenses  on  the  cold  exterior  surfaces  of  vessels  in  crowded 
rooms  possesses  the  same  character,  and  acquires  in  a  short  time  an  offensive  odor-:  now  this 
is  to  a  great  extent  the  case  with  the  water  of  ordinary  condensers  when  allowed  to  become 
spontaneously  aerated  (fti  board  ship.  Thus  water,  though  distilled,  if  kept  in  tainted 
rooms,  will  soon  become  foul.  The  only  condition  necessary  for  distilled  water  not  to  be- 
come putrid  or  oifensive  is  to  saturate  it  with  pure  air,  because  in  that  case  there  is  no 
room  left  for  other  gases  to  impregnate  it,  (at  least,  practically  speaking,  and  in  the  ordi- 
nary conditions  of  domestic  or  of  ship  economy,)  and  to  keep  it  in  covered  vessels  or  tanks. 

Now,  although  aeration  alone  is,  as  I  have  just  said,  powerless  to  destroy  the  nauseous 
odor  of  distilled  water  witliin  a  time  practically  usef\d,  this  aeration,  when  effected  in  the 
manner  which  I  have  described,  is  of  the  utmost  importance;  since  if  even  all  the  other 
conditions  of  the  problem  had  been  complied  with — all,  except  that  one,  the  apparatu.s, 
economical  and  perfect  though  it  might  have  been  in  all  other  respects,  would  have  been 
comparatively  useless.  I  would  strongly  urge  the  importance  of  aerating  the  fresh  water  in 
the  manner  leldch  I  have  described — that  is  to  say,  not  with  ordinary  atmospheric  air,  Init 
with  that  which  was  naturally  contained  in  the  water  before  its  distillation  ;  because  aerating 
it  mechanically  with  ordinary  atmospheric  air,  by  simple  ventilation  or  agitation,  is  far  from 
answering  the  purpose  so  well,  for  the  reasons  which  I  have  already  stated.  Having  thus 
found  thac  the  cause  of  the  odor  and  taste  was  due  to  the  presence  of  empyreumatic  pro- 
ducts, it  became  evident  that,  whereas  the  fresh  water  produced  by  my  apparatus  was 
aerated  in  the  same  manner  and  to  the  same  extent  as  that  obtained  from  the  very  best 
s  jurces,  and  equal  to  it  in  every  other  respect,  the  removal  of  these  ill-smelling  and  ill-tast- 
ing p;iueiples  was  the  last  obstacle  to  the  entire  success  of  the  operation. 

Xow,  if  a  tree,  for  example,  after  having  been  cut  down,  is  left  exposed  to  the  action 
of  the  air  on  the  spot  on  which  it  lies,  we  know  that,  in  the  course  of  time,  its  exterior  be- 
comes soft  and  friable,  and  that  it  gradually  crumbles  into  dust.  The  tree,  in  that  case,  is 
said  to  be  decaying;  and,  in  Cifjct,  after  a  greater  or  less  number  of  yea\-s,  it  will  be  found 
t  >  have  completely  disappeared ;  all  its  combustible  parts,  that  is  to  say,  all  those  parts 
w.iich  would  have  been  burnt  off  if  the  tree  had  Ijcen  set  fire  to,  have  vanished,  and  been 
volatilized,  nothing  being  left  behind  l)ut  the  incombustil)lc  parts,  that  is  to  say,  the  earthy 
constituents  of  the  tree.  Whether  the  tree  is  destroyed  l>y  actual  burning  or  by  sjiontnue- 
on.i  deca'j,  the  rosult  is  the  same  ;  the  only  difference  is,  that  in  the  first  case  the  combustion 
is  rapid,  and  is  energetically  accomplished,  with  disengagement  of  heal  and  of  light,  in  a 
few  hours ;  in  the  second  case,  the  combustion  is  slow,  without  sensible  elevation  of  tem- 
perature, and  a  period  of  thirty,  or  perhaps  forty  years  may  be  rciiuired  to  accomplish  it, 
and  for  the  tree  to  disappear  completely  :  it  is  only  a  question  of  time  ;  whether  the  ti  ee  is 
burnt  in  afire,  or  allowed  to  decay  in  the  air,  the  final  result  is  the  same;  the  carbon  and  hy- 
drogen of  its  wood  being  oxidized,  or  l)urnt  by  the  oxygen  of  the  air,  give,  the  one  carl)()nic 
acid,  the  other  water,  both  of  which  disappear,  and  a  fixed  residue,  namely,  asltcs,  remains. 
Uiit  if,  instead  of  leaving  the  tree  whole,  it  be  cut  into  pieces,  into  sliavings,  into  fragments 
of  shavings,  into  shreds — then  its  coinl)ustion  in  a  fire  will  be  comi)leted  in  a  few  moments; 
oi'  spontancou.sly  in  a  few  months,  as  indeed  is  the  ca.se  with  farm-yard  manures,  winch  are 
.spread  on  tiie  ground,  and  of  which  notinng  remains  in  the  ensuing  year — nothing  liut  the 
iucombustifile  pari  thereof — the  earthy  portion,  the  ashes,  mixed  with  the  soil. — How  is  it 
tlial  a  corpse  which,  while  putrefying,  evolves  a  revolting  odor,  l)ecomes  inodorous  when 
it  is  put  into  a  hole  in  the  ground,  covered  with  earth,  wherein  it  contiinies  nevertheless  to 
decay  and  to  rot,  so  entirely  and  eflectualiy,  that  irtler  a  certain  time  nothing  remains  but 


1082  WATER,  SEA. 

bone?,  or  the  earthy  matter  of  those  bones  ?  What  has  become  of  the  muscles,  of  the  fat, 
of  the  nerves,  tendons,  tissues  of  all  kinds"?  They  have  been  burnt,  oxidized,  converted 
into  carbonic  acid  and  water ;  the  sulphur  thereof  has  been  converted  into  sulphuretted 
hydrogen,  and  that  again  into  sulphuric  acid  and  water  ;  the  nitrogen  has  been  converted 
into  ammonia,  &c.  &c.  Whence  it  is  seen,  that  all  dead  organic  matter  is  eventually  burnt 
up  by  the  oxygen  of  the  air ;  and  that  this  combustion,  whether  rapid  or  slow,  is  accelerat- 
ed by  the  greater  or  less  degree  or  state  of  division  in  which  it  is  exposed  to  the  action  of 
that  gaj?. 

Now  Dr.  Stenhouse,  several  years  ago,  I  believe,  foimd  that  the  power  which  charcoal 
possesses  of  purifying  tainted  air  is  owing  to  its  burning  in  an  insensible  manner  the  sub- 
stances to  which  the  bad  odor  was  due ;  and  acting,  therefore,  upon  this  discovery,  I  con- 
ceived that  in  order  to  burn  a  substance  spontaneously  in  that  manner,  it  mattered  not 
whether  the  oxygen  of  the  medium  into  which  the  said  substance  was  placed  was  a  mixture 
of  oxygen  and  nitrogen,  (atmospheric  air,)  or  a  mixture  of  oxygen  and  water,  (water  aerated 
by  my  process,)  since  oxjigen  alone  was  the  supporter  of  combustion,  the  vitroffen  having 
nothing  to  do  with  the  burning  of  the  substance,  any  more  than  the  prater  of  the  aerated 
water.  And  accordingly,  on  experimenting  in  that  direction,  I  found  that  charcoal  has  the 
power  of  destroying  the  empyreuma  of  distilled  water  u-/ie7i  such  uatcr  is  AJiitATED,  Ijjat  is 
to  say,  when  it  contains  free  oxygen.  I  found  by  experiments,  performed  on  a  somewhat 
extensive  scale  for  many  months,  that  two  cubic  feet  of  charcoal  are  sufficient  to  remove 
entirely  the  empyreurnatic  odor  and  taste  of  distilled  water,  produced  at  the  rate  of  500 
gallons  por  diem,  and  that  the  charcoal  iiever  icants  reneicing.  because  it  does  not  act  as  a 
filter,  but  as  afire  grate,  the  substance  burnt  being  the  empyreumatic  product,  and  the  re- 
sult of  the  slow  combustion  thereof  being  the  ordinary  products  of  combustion,  to  wit,  car- 
bonic acid  and  water.  I  have  every  reason  to  believe,  from  the  length  of  time  during 
which  several  of  my  apparatuses  have  been  in  operation,  both  on  board  a  large  number  of 
ships  and  on  land,  that  such  a  filter  once  made  will  last  for  ever,  because  the  charcoal  dis- 
infects the  water,  so  to  speak,  as  it  docs  air,  not  by  mechanical  separation,  but  by  actual, 
though  insensible  combustion.  The  water  as  it  issues  from  the  apparatus  is  perfectly  sweet, 
tasteless,  inodorous,  and  saturated  with  its  proper  and  normal  quantity  of  oxygenized  air 
and  carbonic  acid ;  it  is  of  sparkling  clearness,  and  being  refrigerated  in  traversing  the 
sheaf  of  pipes  of  the  refrigerator  3,  surrounded  by  cold  sea  water  at  the  lower  part  of  the 
apparatus,  it  is  fit  for  immediate  use. 

These  qualities  I  sincerely  affirm  are  not  in  the  slightest  degree  exaggerated,  and  a 
multitude  of  testimonials  establish  in  an  incontrovertible  manner  that  such  is  truly  the  case. 

And  thus  is  the  second  condition,  that  of  aeration,  of  digestibility,  of  wholesomeness 
accomplished,  whereby  the  fresh  water  produced  is  rendered  at  once  not  only  drinkable,  but 
so  sweet,  limpid,  and  fresh,  that  it  cannot  be  distinguished  from  the  very  best  spring  water. 

During  the  experiments  or  comparative  trials  which  took  place  at  Portsmouth  in  1859 
before  the  Committee  of  the  Admiralty,  between  my  apparatus  and  that  of  the  late  Sir 
Thomas  Grant,  with  which  all  H.  M.  steam  ships  were  then  provided,  a  very  curious  pheiK)m- 
enon  took  place,  which  corroborated  in  a  startling  manner  the  explanation  which  I  have 
given  of  the  nauseous  odor  of  ordinary  distilled  water.  The  circumstances  under  which  the 
phenomenon  was  produced  were  as  follows : — 

On  the  20th  of  October,  1859,  steam  having  been  got  up  in  one  of  the  boilers  of  IT.  M. 
ship  "Odin,"  that  steam  was  turned  in  precisely  equal  quantity  to  each  of  the  apparatuses 
under  trial,  (Sir  T.  Grant's  and  mine.)  The  first  experiment  was  completed  about  3-30  of 
the  ensuing  morning.  The  fire  was  then  "  banked  up"  for  the  rest  of  the  night ;  the  gen- 
eral steaincock  supplying  the  steam  to  both  apparatuses  was  turned  off;  both  apparatuses  of 
course  became  quite  cold,  and  the  residuary  steam  in  the  boiler  was  used  by  the  engineer 
for  working  his  donkey  pump.  Toward  12  o'clock  of  the  cu.suing  day  the  experiments 
were  resumed ;  steam  again  got  up  for  the  purpose,  and  an  equal  quantity  of  it  turned  as 
before  into  each  apparatus. 

When,  however,  a  Ijoiler  is  not  at  work,  or  has  been  even  a  few  hours  without  working, 
its  steam  room  as  well  as  the  steam  pipe  is  of  course  filled  with  common  air  instead  of  with 
steam  ;  wherefore  the  steam  which  is  at  first  generated  in  the  said  boiler,  instead  of  being 
steam  only,  is  a  mixture  of  steam  and  air.  Accordingly  when  steam  is  at  first  turned  into 
my  apparatus,  a  small  cock  with  which  the  latter  is  provided  is  simultaneously  opened  for 
the  purpose  of  allowing  an  escape  for  that  air  which  otherwise  would  to  a  certain  extent 
interfere  with  the  condensation  of  the  steam,  and  retard  the  boiling  of  the  sea  water  in  my 
evaporator.  In  conformity  with  this  practice,  as  soon  as  the  steam  from  the  ship's  boiler 
was  turned  into  both  apparatuses,  (Sir  T.  Grant's  and  mine,)  the  small  cock  above  alluded  to 
wa-4  opened,  whereupon  a  rush  of  air  escaped  through  it  as  usual ;  but  I  then  observed  for 
the  first  time  that  this  air  escaping  from  my  cold  apparatus,  (for  no  steam  had  as  yet  come 
into  it,)  instead  of  being  merely  atmospheric  acid,  was  an  inflammable  gas,  which,  being 
•  brought  in  contact  with  a  lighted  lamp,burut  with  a  thin  bluish  flame,  due  evidently  to  the  pres- 
ence of  carburetted  gases  resulting  from  the  decomposing  action  exercised  by  the  heated  sur- 


WATEK,  SEA. 


1083 


faces  of  the  boiler,  not  only  on  the  organic  matters  naturally  contained  in  all  natural  waters,  as 
discovered  by  the  experiments  which  I  made  in  1850,  and  to  whicii  I  have  already  alluded, 
but  also  on  the  fatty  matters  of  the  packings  of  the  pistons,  and  introduced  into  the  boiler 
by  the  feed  pump,  but  in  all  probability  principally  from  the  decompostion  of  the  melted 
tallow  which  is  generally  forced  in  it  by  means  of  a  syringe  ad  /loc,  for  the  i)urpose  of  pre- 
venting "priming,"  which  introduction,  in  my  humble  judgment,  is  not  under  certain  circum- 
stances altogether  free  from  danger. 

I  believe  that  most  of  the  boiler  explosions  unsatisfsictorily  explained  or  absolutely  un- 
accounted for  are  referable  to  the  presence  of  the  gases  above  alluded  to,  and  of  atmospheric 
air,  in  such  proportions  as  to  form  a  detonating  mixture,  which  is  then  inflamed,  possibli/,  by 
the  unduly  heated  surfaces  of  the  boiler  above  the  water  level,  but  in  my  opinion  nmch 
more  probably  by  the  electricity  resulting  from  the  friction  of  the  vesicular  steam  against 
the  steam  pipe  and  other  surfaces.  In  ettect,  it  is  well  known  that  the  steam  which  issues 
from  a  boiler  is  always  highly  charged  with  electricity,  and  that  electric  sparks  several  inches 
in  length  may  and  have  been  drawn  from  it,  especially  when  the  boiler  happens  accident- 
ally or  otherwise  to  be  isolated.  On  the  other  hand,  a  mixture  of  these  gases  may  be 
exploded  when  mixed  with  atmospheric  air,  in  certain  proportions  varying  between  1  of  the 
former  and  from  6  to  10  of  the  latter,  the  maximum  effect  being  when  1  of  carburetted 
hydrogen  is  mixed  v.'ith  8  of  atmospheric  air.  Given,  therefore,  the  conditions  of  a  suf- 
ficiently insulated  boiler,  and  a  mixture  therein  of  the  above-mentioned  gas  and  atmospheric 
air  in  proportions  ranging  between  one  of  the  first  and  six,  seven,  eight,  or  nine  of  the 
second,  an  explosion  of  the  boiler,  of  a  more  or  less  formidalile  nature,  may  take  place. 

I  have  already  stated  that  sea  water  contains  salt  in  the  proportion  of  about  1  lb.  to  33 
lbs.  of  water.  Now  when  sea  water  is  evaporated,  all  the  steam  produced  therefrom  being 
of  course  fresh  water,  all  the  salt  which  that  water  contained  is  left  behind,  that  is  to  say, 
the  salt  previously  contained  in  the  evaporated  portion  is  left  in  that  portion  which  is  not 
yet  evaporated,  and  which  is  therefore  more  impregnated  with  salt  than  before.  If  this 
salt  be  not  i^emoved,  and  the  evaporation  is  continued,  it  goes  on  accumulating,  furring  and 
incrusting  the  vessel,  and  very  soon  destroys  it.  Tliis  is,  in  fact,  an  inconvenience  common 
not  only  to  all  the  sea-water  stills  hitherto  contrived,  but  to  the  boilers  of  marine  engines ; 
for  no  boiler  is  safe  from  incrustation  as  soon  as  about  one  half  of  the  sea  water  admitted 
into  it  has  been  evaporated  ;  that  is,  as  soon  as  the  sea  water  has  been  saturated  by  con- 
centration so  as  to  contain  1  lb.  of  salt  in  about  16  lbs.  of  water. 

My  apparatus  is  not  liable  to  these  incrustations  or  deposits  of  salt,  because  the  sea 
water  circulates  in  it  in  a  constant  and  uninterrupted  manner,  a  discharge  taking  place  at 
the  same  time  through  cock  45,  {socjic/.  685,)  so  as  to  leave  the  sea  water  in  the  apparatus 
superabundantly  diluted  to  hold  in  perfect  solution  the  whole  of  its  salt ;  in  fact,  the  sea 
water  discharged  through  that  cock  contains  only  about  one  half  per  cent,  more  salt  than  it 
did  when  it  first  entered  the  apparatus,  which  is  a  perfectly  insignificant  increase. 

The  different  parts  of  the  apparatus  being  made  of  sheet,  riveted,  galvanized  iron  plates 
and  of  cast  iron,  connected  in  a  substantial  manner  by  screws  and  bolts,  without  soldering 
or  brazing  of  any  kind  or  in  any  part,  it  is  perfectly  impossible  that  it  should  go  out  of 
order  by  any  accident  short  of  those  cases  of  force  majeure  which,  unfortunately,  arc  too 
often  the  cause  of  the  ruin  or  wreck  of  the  ship  itself. 

I  shall  now  give  a  description  ofthefir/s.  685  and  68G,  in  which  the  same  numbers  rep- 
resent the  same  organs.  Fir/.  685  is  a  section  on  the  same  plane,  showing  tiie  mode  of 
action  of  the  apparatus,  without  reference  to  the  real  position  of  its  constituent  parts.  Fig. 
686  is  a  correct  front  elevation  of  the  apparatus. 

1  shows  the  large  entrance  tube  for  the  sea  water :  this  tube  is  connected  to  a  lai-gc 
cock,  communicating  with  the  sea  through  the  side  or  bottom  of  the  ship  ;  or  else  flanged 
to  a  much  smaller  pipe  connected  with  a  pump,  by  means  of  which  the  ajjparatus  is  su])plied 
with  water  from  the  sea,  which  thus  penetrates  into  the  refrigerator  3,  through  the  tube  of 
communication  4,  and  thence  passes  round  the  slieaf  of  pipes  15,  in  the  said  refrigerator, 
tin-ough  another  communication  tube  5,  into  the  condenser  6,  as  shown  by  the  arrows,  and 
up  the  large  vertical  tube  8,  whence  the  surplus  sea  water  pumped  up  Hows  away  through 
the  pipe  9,  in  the  direction  indicated  by  the  arrows.  Tiie  condenser  6  being  thus  com- 
pletely filled  up  with  sea  water,  on  opening  the  cock  10,  the  sea  water  jiassing  tlnough  i)ipo 
11  falls  into  the  feed  and  priming  Irox  Iti,  and  thence  tlu-ough  pipe  13  into  the  evaporator 

14,  filling  it  up  to  a  certain  level,  regulated  by  opening  or  shutting  the  cock  10  so  as  to 
maintain  the  sea  water  at  tlie  proper  level  in  the  evaporator  14. 

3,  Rcfricfcrator.  It  is  a  hoi'izontal  case  pervaded  with  pipes,  15,  placed  horizontally  in 
it.     The  sea  water,  being  introduced  into  this  refrigerator,  circulates  round  a  sheaf  of  jiipes 

15,  held  between  the  caps  16,  at  each  end  of  the  .sai<l  refrigerator,  so  that  the  IVesli  water 
whicli  has  ))cen  condensed  in  tlie  pipes  23  of  the  evaporator  14,  and  in  the  ])ipes  17  of  the 
condenser  6,  is  thereby  cooled  down  to  the  (enii)eiature  of  the  sea  water  outside. 

4,  a  large  pipe  connecting  the  pipe  1  witli  the  refrigerator  3. 

5,  largo  pipe  connecting  the  reirigerator  3  with  the  condenser  6. 


108-4 


WATEK,  SEA. 


6,  Condenser.     It  is  a  cylinder  containing  a  sheaf  of  pipes  17,  into  which  the  non-aer- 
ated steam  from  the  evaporator  is  condensed  by  the  sea  water  which  surrounds  them. 

7,  large  outlet  tube,  used  only  when  the  apparatus  is  put  below  the  level  of  the  sea. 


WATER,  SEA.  1085 

8,  large  upright  tube,  which,  when  the  apparatus  is  placed  on  deck,  is  turned  upward, 
and  is  of  such  a  length  that  the  sea  water  wliich  is  forced  tlirough  tlie  apparatus  by  means 
of  the  pump,  or  otherwise,  may  be  raised  a  few  feet  above 'the  whole  apparatus,  sothat  there 
may  be  in  the  large  tube  8  a  columu  of  sea  water  higher  than  the  condenser  G,  in  order  to 
keep  it  quite  full. 

9,  overflow  pipe  for  the  escape  of  the  excess  of  sea  water. 
W,  cock  of  the  feed  pipe. 

11,  feed  pipe,  one  end  of  which  is  inserted  in  the  condenser  G,  and  the  other  end  in  the 
feed  and  priming  bo.x  12.  It  is  through  this  feed  pipe  11  that  the  sea  water  is  led  from  the 
top  of  the  condenser  into  the  feed  and  priming  box  12,  by  opening  the  cock  10  to  a  suit- 
able degree,  as  said  before,  1. 

12,  feed  and  priming  box.  It  is  a  box  into  which,  on  opening  the  cock  10,  the  sea 
water  supplied  from  the  condenser  6,  by  pipe  11,  passes  through  pipe  13  into  the  evapora- 
tor 14,  which  is  thus  fed  with  the  proper  quantity  of  sea  water.  This  feed  box  receives  also 
anv  priming  which  might  be  mechanically  projected  by  or  carried  along  with  the  steam 
through  pipe  22.  In  such  a  case  the  priming  is  then  returned  to  the  evaporator  14,  through 
pipe  13. 

13,  feed  pipe  leading  to  the  sea  water  to  be  evaporated  into  the  evaporator  14. 

14,  Evaporator.  It  is  a  cylinder  containing  a  sheaf  of  pipes  23,  with  their  caps,  24,  at 
each  end,  immersed  in  the  sea  water,  part  of  which  is  to  be  evaporated. 

15,  sheaf  of  pipes  of  the  refrigerator  3,  for  the  purpose  of  cooling  the  fresh  water  pro- 
duced ;  has  already  been  descril)ed  under  S'o.  3. 

16,  caps  of  the  refrigerator  3,  so  arranged  that  by  means  of  the  divisions  reserved  in 
the  said  caps,  the  steam  from  tlie  boiler,  and  that  evolved  from  the  evaporator  14,  are  both 
made  to  travel  to  and  fro  through  the  different  pipes  15  consecutively,  so  as  eventually  to 
flow  out  in  a  mixed  and  cold  state  through  the  cock  32,  into  the  filter  33,  and  finally  through 
the  tube  34  in  a,  perfect  state. 

17,  sheaf  of  pipes  placed  between  the  two  caps  18  of  the  condenser  6,  for  the  purpose 
of  condensing  the  aerated  steam  from  the  evaporator  14. 

18,  caps  covering  the  ends  of  the  sheaf  of  pipes  17  placed  in  the  condenser  G. 

19,  aerating  pipe,  leading  the  air  which  separates  from  the  sea  water  round  the  pipes  17 
of  the  condenser  6  into  the  steani'room  or  chatnber  of  the  evaporator  14.  It  is  by  means 
of  this  aerating  pipe  that  tlie  fresh  water  condensed  in  the  condenser  6  becomes  aerated, 
and  this  aeration  is  accomplislied  as  follows  :  — 

As  the  steam  from  the  evaporator  14  enters  the  pipes  within  the  condenser  G  at  the  top 
thereof,  through  the  pipe  21,  it  follows  that  the  sea  water  at  the  top  of  the  condenser  G  is 
brouglit,  as  was  already  said  under  No.  11,  to  a  temperature  which,  at  the  top  of  the  said 
condenser,  is  as  high  as  206'  or  208'  Fahr. ;  this  temperature,  as  we  also  said.  No.  11, 
gradually  diminishes  from  the  top  downward,  bu:  at  a  zone  corresponding  to  al)out  the  point 
marked  by  Xo.  7,  the  temperature  of  the  sea  water  round  the  sheaf  of  pipes  17  is  reduced 
to  about  140'  Fahr.  As  the  air  naturally  contained  in  the  sea  water  begins  to  separate 
therefrom  at  about  130'  Fahr.,  that  in  the  sea  water  round  the  sheaf  of  pipes  17,  l)etween 
No.  7  and  the  top  of  the  condenser,  becoming  entirely  liberated,  ascends,  by  virtue  of  its 
lighter  weight,  to  the  top  of  the  said  condenser  6  ;  it  tfien  passes  through  the  aerating  pipe 
19,  and  is  tlien  poured  into  the  steam  room  37  of  the  evaporator  14,  wherein  it  mixes  with 
the  secondary  steam  therein  produced  by  the  evaporating  pipes  23.  This  mixture  of  air  and 
steam  passes  then  througli  pipes  22  into  the  feed  and  priming  box  12,  and  thence  through 
pipe  21  into  the  sheaf  of"  pipes  17.  The  air  being  there  absorbed  during  the  condensation 
of  this  secondary  steam,  with  which  it  was  mixed,  the  condensed  fresh  water  resulting  there- 
from becomes  thus  super-aerated,  and  in  passing  subsequently  through  the  cock  39  of  pipe 
30  into  a  portion  o^he  pipes  15  of  the  refrigerator  3,  it  mixes  there  with  the  non-aerated 
fresh  water,  resulting  from  the  steam  of  the  boiler,  which  has  condensed  in  the  pipe  23  of 
the  evaporator  14,  which  condensed  water  (lows  tlirough  i)i]>o  25  into  the  steam  trap  26, 
thence  along  pipes  29  and  31,  and  tin-ough  the  cock  41,  into  the  other  portion  of  pipes  15 
of  the  refrigerator  3.  The  condensed  water  from  the  pi|)es  23  of  the  evaporator  14  be- 
comes aerated  by  the  excess  of  air  contained  in  the  condensed  water  of  the  pipes  17  of  the 
condenser,  in  its  passage  with  the  latter  through  tlie  pipes  15  of  the  refrigerator  3,  in 
traversing  which  the  con»bined  waters  are  cooled  down  to  the  temperature  of  the  sea  water 
round  the  said  sheaf  of  jiipes  in  the  refrigerator.  And  tlie  result  is,  that  after  passing 
through  the  filter,  it  flows  at  34  in  tiie  state  of  perfectly  cold  fresh  water,  thoroughly  aerated, 
and  of  matchle.-JS  f|uality. 

20,  level  to  which  the  .sea  water  rises  in  the  aerating  pipe  10. 

21,  pipe  conducting  the  mixture  of  .'^team  and  air  from  the  feed  and  priming  box  12  into 
the  sheaf  of  pipes  17  of  the  condenser  G. 

22,  pipe  leading  the  mi.xture  of  steam  and  air  from  the  evaporator  14  into  the  feed  and 
priming  box  12,  where  any  salt  water,  with  wliii'h  it  may  be  mixed,  is  arrested  and  returneti 
to  the  evaporator  14,  through  pipe  13,  wiiile  the  pure  steam,  piu<siiig  through  pipe  21,  is 
next  condensed  in  the  sheaf  of  pipes  17  of  the  condenser  6. 


1086  WATER,  SEA. 

23,  sheaf  of  pipes  immersed  in  the  sea  water  36  of  the  evaporator  14,  and  in  which  pipes 
the  steam  coming  from  the  boiler  through  tlic  steam  pipe  35  is  condensed,  after  which  it 
tiows  as  distilled  but  7ion-aerated  Fresh  water  into  the  lower  cap  24,  and  thence  through  pipe 
25  into  the  steam  trap  26,  thence  through  pipes  29  and  31  and  cock  41  into  the  sheaf  of 
pipes  15  of  the  refrigerator  3. 

24,  upper  and  lower  caps  covering  the  two  extremities  of  pipes  23  of  the  evaporator  14, 
into  wliich  pipes  the  steam  from  the  boiler  diffuses  itself,  and  is  condensed,  after  which  it 
flows  in  the  state  of  distilled  but  non-aiirated  fresh  water,  through  pipe  25  into  the  steam 
trap  26,  and  thence  through  pipes  29  and  31  into  the  pipes  15  of  the  refrigerator  3,  in 
which  it  mixes  with  the  aerated  water  coming  through  pipe  30,  and  passing  through  pipe  32 
into  the  filter  33,  finally  issues  at  pipe  34  in  the  state  of  cold,  matchless,  aerated  fresh  water, 
inimediateli/  fit  for  consumption. 

25,  pipe  for  the  exit  of  the  condensed  non-aerated  fresh  water  from  the  sheaf  of  pipes 
23  of  the  evaporator  14 ;  which  water,  after  entering  the  steam  trap  26,  issues  therefrom 
through  pipe  29,  and  then  enters  the  refrigerator  as  already  said. 

26,  steam  trap.  It  is  a  box  containing  a  float  28,  provided  with  a  plunger  acting  in  such 
a  way  that  when  the  box  contains  only  steam,  or  a  quantity  of  condensed  water,  not  suffi- 
cient to  buoy  the  float,  it  (the  plunger)  closes  the  exit  pipe  29 ;  but  as  soon  as  the  condensed 
water  has  accumulated  in  quantity  sufficient  to  buoy  the  float  up,  the  plunger,  of  course, 
rising  with  the  float,  no  longer  obstructs  the  exit  pipe  29,  and  accordingly  the  condensed 
water  may  then  escape  as  fast  as  it  is  produced. 

27,  small  pet  cock  on  the  top  of  the  cover  of  the  steam  trap  26. 

28,  float  already  described,  (26.) 

29,  pipe  leading  the  condensed  non-aerated  water  from  the  steam  trap  26,  through  pipe 
81,  into  the  pipes  15  of  the  refrigerator  3,  in  which  it  mixes  with  the  aerated  fresh  water 
from  the  condenser. 

30,  pipes  leading  the  condensed  aerated  water  from  the  pipes  17  of  the  condenser  6,  into 
the  pipes  15  of  the  refrigerator  3,  in  which  it  mixes  with  the  non-aerated  water  from  the 
steam  trap  26.  This  pipe  is  provided  with  two  cocks,  38  and  39,  for  the  purpose  of  clean- 
ing the  condenser  6. 

31,  pipe  leading  the  condensed  non-aerated  water  from  pipe  29  into  the  pipes  15  of  the 
refrigerator,  in  which  it  mixes  with  the  aerated  water  from  the  condenser. 

32,  exit  pipe  and  cock,  through  which  the  mixed  distilled  waters,  (aerated  and  non-aer- 
ated,) after  passing  through  the  pipes  of  the  refrigerator,  enter  the  filter  33. 

33,  filter  for  receiving  the  condensed  water  from  both  the  evaporator  and  the  condenser, 
as  they  issue  in  a  mixed  and  cold  state  from  the  pipes  15  of  the  refrigerator  3,  through  cock 
and  pipe  32. 

34,  pipe  for  the  final  exit  of  the  perfect  aerated  fresh  water. 

85,  steam  pipe  and  cock  leading  the  steam  more  or  less  under  pressure  from  any  de- 
scription of  boiler  to  the  pipes  23  of  the  evaporator  14.  It  is  connected  at  one  end  with 
the  steam  boiler,  and  at  the  other  with  the  upper  cap  24  of  the  evaporating  pipes  23. 

36,  sea  water,  to  be  evaporated  Ijy  the  steam  pipes  23,  of  the  evaporator  14. 

37,  steam  room,  or  space  into  which  the  air  naturally  contained  in  the  sea  water  used 
for  condensation  in  the  condenser  6,  is  poured  through  the  aeiating  pipe  19,  so  as  to  mix  with 
the  steam  generated  V)y  the  pipes  23  of  the  evaporator. 

38  and  39,  two  cocks  on  pipe  30,  placed  between  the  condenser  6  and  the  refrigerator 
3,  for  the  purpose  of  clearing  the  pipes  17  of  the  condenser  G. 

40  and  41,  two  cocks  placed  on  pipe  31,  for  the  purpose  of  clearing  the  pipes  23  of  the 
evaporator  14  and  steam  trap  26. 

42,  cock  placed  between  the  cap'16  of  the  refrigerator  3,  and  the  cock  32,  for  the  pur- 
pose of  cleaning  the  pipes  15  of  the  refrigerator  3. 

43,  glass  water-gauge. 

44,  breathing  pipe.  It  is  a  small  pipe,  one  end  of  which  is  in  communication  with  the 
lower  cap  18  of  the  condensing  pipes  17,  and  the  other  end  is  open  to  the  atmosphere. 
The  object  of  this  pipe  is  not  only  to  remove  pressure  from  the  cylinders,  but  likewise  to 
afford  an  exit  for  the  excess  of  air  generated. 

45,  brine  cock. 

46,  opening  reserved  in  the  feed  and  priming  box. 

The  first  thing  to  be  done  is,  of  course,  to  cliarge  the  apparatus  with  sea  water.  This  is 
done  by  establishing  a  communication  between  the  apparatus  and  the  sea  water  round  the 
ship.  This  is  easily  done  by  turning  on  the  large  cocks,  or  Kingston  valves,  connected  with 
the  large  orifices  2  and  7,  (see  the  figures;)  whereupon  the  salt  water  immediately  fills  up 
both  the  refrigerator  3  through  the  passage  4  and  the  condenser  6  through  the  passage  5,  up 
to  a  certain  point  (20)  of  the  aerating  pipe. 

Opening  now  the  cock  10  of  the  feed  pipe  11,  the  sea  water  will  pass  from  the  condenser 
6  into  the  feed  and  priming  box  12,  and  tiicnce  through  pipe  13  into  the  evaporator  14, 
where  it  should  be  allowed  to  rise  up  to  about  one  third  of  the  glass  gauge  43,  when  the 


WATER,  SEA. 


lOSI 


cock  10  should  be  shut  up.  The  apparatus  being  thus  charged  with  its  proper  quantity  of 
sea  water ;  the  steam  boiler  being  ready  to  furnish  the  necessary  steam ;  and  admitting,  of 
course,  that  the  steam  pipe  35  is  in  communication  with  the  said  boiler,  the  next  thing  to 
be  done  is  to  open  the  steam  cock  35,  shutting  at  the  same  time  the  cocks  39,  41,  and  32, 
and  opening  cocks  38,  40,  and  42,  and  likewise  the  small  pet  cock  2  7  of  the  steam  trap  2G. 
On  opening  this  small  pet  cock  27,  nothing  but  air  will  at  first  rusli  out ;  Ijut,  piesently, 
steam  will  issue  from  it ;  it  should  then  l)e  closed  more  and  more  gradually  as  the  steam  is 
seen  issuing  from  it  with  rapidity ;  and  it  should  eventually  be  left  almoxt,^  but  not  alto- 
gether, shut  up,  so  as  to  leave  only  room  for  the  smallest  possible  wreath  of  steam  slowly 
to  issue  from  it.  As  soon  as  the'  steam  cock  33  is  open,  the  steam  from  tiie  boiler  will 
rush  through  that  cock  into  the  sheaf  of  pipes  23  of  the  evaporator  14,  in  which  pipes  it 
will  be  condensed  by  the  sea  water  which  surrounds  them,  and  it  will  then  flow  in  the  state 
of  condensed  uon-aeVated  distilled  water  through  the  pipe  25  into  the  steam  trap  2<j;  lift  up 
the  float  28,  and  passing  through  pipe  20,  will  flow  through  cock  4i>,  its  further  progress 
being  intercepted  by  cock  41,  which  is  shut,  as  said  before.  As  soon  as  the  condensed 
water  flows  out  in  a  "clear  state  from,coek  40,  shut  it,  and  open  cock  41,  so  that  it  may  pass 
into  the  pipes  15  of  the  refrigerator  3,  and  out  at  cock  42.  In  a  few  moments  the  con- 
densed water  will  flow  out  in  a  clear  state  from  that  cock  42,  which  should  then  be  closed, 
opening  at  the  same  time  cock  32,  so  that  it  may  pass  into  the  filter  33. 

But  the  steam  within  the  sheaf  of  pipes  23  of  the  evaporator  14  soon  brings  the  sea 
water  round  them  to  the  boiling  point,  and  converts  part  of  it  into  steam.  This  pure  sec- 
ondary steam  from  the  evaporator,  issuing  then  from  the  priming  box  12,  passes  through 
pipe  21  into  the  pipes  17  immer.sed  in  the  salt  water  of  the  condenser  6,  and  being  con- 
densed in  the  said  pipes,  is  allowed  to  flow  out  at  the  cock  38  (which  has  been  opened  at  start- 
ing) as  long  as  it  is  not  clear.  In  a  short  time,  however,  it  will  flow  out  from  that  cock, 
38,  in  a  perfectly  clear  state;  when  this  takes  place  shut  this  cock  38,  and  open  cock  3p, 
whereupon  it  will  flow  into  the  pipes  15  of  the  refrigerator  3,  in  which  pipes  it  will  mix 
with  that  coming  from  the  pipes  23  of  the  evaporator  14,  and  flow  with  it  through  the  .said 
pipes  15,  and  thence  into  the  filter  33  through  the  cock  32,  the  whole  issuing  finally  from 
the  filter  33  through  pipe  34,  in  the  state  of  perfect  aerated  fresh  water. 

From  this  brief  description  of  my  marine  fresh-water  apparatus  it  may  be  Been  that  a 
quantity  of  fresh  water  is  produced  always  double  that  which  can  be  evaporated  from  any 
boiler  whatever,  and  indeed  by  increasing  the  number  of  evaporators  lib.  of  coals  may  thus 
be  made  to  yield  30  or  40  lbs."  of  fresh  water  of  matchless  quality ;  that  the  small  volinno 
of  the  apparatus,  the  large  quantity  of  fresh  aerated  water  which  it  produces,*  at  an  ex- 
tremely small  cost,  its  perfect  safety,  permanent  order,  and  the  case  with  which  it  can  be 
disconnected  and  all  its  parts  reached,  not  only  render  it  preeminently  suited  to  naval  pur- 
poses, but  likewise  to  such  stations  or  places  as  are  deficient  in  one  of  the  first  necessaries 
of  life,  saluljrious  fresh  water,  or  where  it  cannot  be  obtained  at  all,  or  only  in  an  insuffi- 
cient, precarious,  or  expensive  manner. — A.  X. 

The  following  letters  were  addressed  to  the  Editor  in  reply  to  an  inquiry  made  by  him 
as  to  the  value  of  Dr.  Xormandy's  invention. 

"Government  Emisration  Board,  8  Park  Street,  "Westminster,  1st  March.  T^fiO. 

"Sir,— I  am  directed  by  the  Emigration  Commissioners  to  acknowledge  the  receipt  of  yr)nr  letter  of 
the  ^Sth  ultimo,  requesting  to  be  furnished  with  any  evidence  they  may  posses.s  as  to  the  good  or  ill 
effects  of  the  use  of  Dr.  Normandy's  distilled  water  on  board  emigrant  ships. 

"  In  replv.  I  am  to  acquaint  you  that  the  Commissioners  have  placed  on  bo.ard  several  of  their  emi- 
grant ships,  Dr.  Normandy's  api>aratus  for  distilling  fresh  fnim  salt  water,  and  that  the  reports  which 
they  have  as  yet  receivedfrom  their  surgeons  in  those  vessels  (who  are  instructed  to  pay  particnhir 
attention  to  the  matter)  are  uniformly  of  a  favor.ible  character — one  gentleman  onlv  having  mentioned 
that  the  water  had  at  first  an  insipid  t.oste  which  subsequently  went  otf.  Tiiis  probably  arose  fn>m  some 
accidental  circumstance  in  the  particular  machine,  as  freedom  from  insipidity  is  one  of  tbo  main  char- 
acteristics of  the  water. 

"I  enclose,  for  your  information,  extracts  from  the  official  reports  made  to  this  Board  by  their  sur- 
geons and  the  colonial  emigration  aironts,  respecting  the  quality  of  the  water  and  its  effects. 
'•  I  have  the  honor  to  be,  sir,  your  obedient  servant, 

"  Robert  Hunt,  Esq."  " S.  Walcott,  St'cretary." 

Extract  from  the  report  of  Dr.  Duncan,  Immigration  Afjcnt,  on  the  ship  "  Cotifance," 
dated  Port  Adelaide,  Jan.  10,  1859  : — 

"A  distilling  apparatus,  invented  by  Dr.  Normandy,  was  sent  out  in  the  'Conflancc'  to  test  its  ofll- 
ciencv. 

"There  arc  two  great  objections  to  water  distilled  in  the  ordinary  manner;  the  first  Is,  that  water 
thus  obtained  is  without  air,  is  unp.al.atable  and  indi^'cstible:  the  second  is,  that  it  contracts,  while  in  tho 
process  of  distillation,  ar  -iiipyrcuuiatic  odor  and  taste;  in  fact,  ordinary  distilled  water  is  6aid  to  bo 
indigestible  and  nauseou.^. 

"These  two  objections  ai.pear  to  be  perfectly  met  bv  Dr.  Normandy's  invention  ;  tho  water  obtain«d 
by  his  proces.s  is  perfectlv  palaUitde.  well  aerated,  and  devoid  of  smell. 

"During  the  passage  of  the  '  Confiance,'  nearly  eleven  thousand  ga'lons  of  water  were  distilled,  and 
is  reported  by  Mie  surgeon  .superintemlent  to  have  been  of  most  excellent  quality,  and  preferred  by  tho 
emigrants  to  tho  water  shipped  on  board  in  casks." 

♦  An  apparatus  4  ft.  6  in.  high,  5  ft.  long,  and  2  ft.  wide,  produces  at  least  24  gallons  of  fresh  water  per 
hour. 


1088  WEAVING  BY  ELECTRICITY. 

Extract  from  the  Report  of  Dr.  Carroll  on  the  ship  "  Comcai/,^^  dated  Melbourne,  Sept 
20,  1858:— 

"The  qualitj-  of  the  water  produced  was,  in  my  opinion,  excellent,  and  most  aereeablo  in  taste;  and, 
so  far  as  my  observation  went,  most  wholesome ;  in  fact,  during  the  hot  weather  I  considered  it  quite  a 
luxury ;  and  I  regrettcil  much  that  the  quantity  produced  was  not  greater.  It  was  also  preferred  by  tho 
passengers  to  the  ship's  water." 

Extract  from  the  Report  of  Br.  Crane  07i  the  ship  ^^ Forest  Monarch,''^  dated  Sidney, 
Jan.  5,  ISoO : — 

"  The  condensed  water  wa.s  very  good,  excelling  in  clearness  and  purity,  and  much  more  palatable 
than  any  water  I  had  ever  previously  seen  on  board  ship,  being  not  unlike  the  rain  water  so  much 
esteemed  in  the  West  Indies.  The  water,  as  it  came  from  the  ajiparatus,  possessed  a  slight  peculi.ir 
taste,  which  varied  in  degree  with  the  purity  of  the  sea  water  employed  in  its  production,  and  -which 
disappeared  on  exposure  to  the  air.  This  peculiar  taste  I  attribute  partly  to  the  excessive  aeration  of 
the  condensed  water,  as  I  have  noticed  a  similar  taste  in  .soda  water  that  has  been  adulterated  for  ehiap- 
ne.^s'  sake,  with  common  air,  and  partly  to  empyreuniatic  products  obtained  from  the  destructive  dialil- 
lation  of  organic  impurities  contained  in  the  sea  water  subjected  to  distillation." 

Extract  from  the  Report  of  Dr.  Rivers  on  the  "  Morayshire,''''  dated  Calcutta,  May  18 
1859:— 

"  The  emigrants  did  not  at  first  like  the  distilled  water,  but  gradually  got  accustomed  to  it,  and  after- 
ward to  preler  it  to  the  ordinary  water.  Those  drinking  it  seemed  better  in  he.alth  than  the  pe(  pie 
using  the  otlier  water,  and  more  free  from  bowel  complaints.  1  Avould,  therefore,  stiongly  recommend 
that  the  water  prepared  from  Dr.  Normandy's  apparatus  be  generally  used  in  all  ships  carrying  Coolies, 
as,  in  my  opinion,  it  is  not  only  wholesome,  but  perfectly  free  from  all  impurities,  besides  not  so  liable 
to  disorder  the  bowels  as  the  common  water." 

Extract  from  the  Report  of  Mr.  James  Crosby,  Immigration  Agent  at  British  Guiana, 
on  the  ship  "  Queen  of  the  East,"  dated  British  Guiana,  Oct.  19,  iS59: — 

"  I  found  also  Dr.  Normandy's  admirable  distilling  apparatus  in  full  operation.  It  is  almost  impos- 
sible  to  spiak  in  too  favorable  terms  of  this  apparatus,  capable  of  producing  five  hundred  gallons  a  day — 
■with  the  consumption,  I  think,  of  only  eight  bushels  of  coals— of  water  apparentlj-  as  pure  and  whole- 
some as  could  bo  drunk,  and  taken  from  alongside  the  ship,  from  the  muddy  and  impure  M-ater  of  tno 
Demerara  river." 

Extract  of  a  letter  from  Dr.  L.  S.  Crane,  surgeon  superintendent  of  the  ship  '■'■Devon- 
shire," dated  Coconada,  Dec.  27,  1859  : — 

The  "Devonshire"  was  dismantled  in  a  hurricane,  by  which  the  apparatus  on  deck  was 
injured. 

"  Since  the  water  apparatus  was  broken,  the  health  of  the  Coolies  has  deteriorated.  After  careful 
observation  I  can  find  no  other  cause  for  the  dysentery  and  diarrhoea  prevailing  than  the  water  they 
drink.  The  ventilation  is  excellent,  the  between-decks  have  been  kejit  beautifully  clean  and  dry— the 
food  is  good  and  well  cooked.  The  rice  (cargo)  has  been  steaming  to  a  certain  extent,  but  the  diseases 
that  arise  from  bad  air, — low  fevers  and  cholera, — have  not  made  their  appearance.  Hesides,  the  crew 
have  suffered  very  much  more  than  the  Coolies,  and  the  only  condition  common  to  both  is  the  water 
they  drink." 

Extract  of  aletter  from  Mr.  C.  Chapman,  surgeon  superintendent  of  the  ship  '■'Euxine," 
to  S.  Walcott,  Esq.,  dated  Madras,  Jan.  23,  18C0: — 

'•In  my  opinion,  the  water  it  (Dr.  Normandy's  apparatus')  produces  is  perfectly  sweet  and  whole- 
some ;  is  far  preferable,  and  preferred  by  all  hands,  to  the  water  in  tanks  or  casks." 

WEAVING  BY  ELECTRICITY.  The  article  Weaving,  and  tho.«e  referred  to  from  it, 
togctlier  with  the  article  on  the  Jacquard  loom,  will  render  the  conditions  necessary  to  the 
production  of  figures  in  any  textile  fabric  tolerably  familiar.  A  brief  notice  of  a  new  inven- 
tion for  employing  electricity  in  weaving  cannot  fail  to  be  interesting. 

So  long  ago  as  1852,  M.  Bonelli  constructed  an  electric  loom,  which  was  exhibited  at 
that  time  in  Turin,  but  the  first  trial  to  which  the  machine  was  submitted  gave  but  small 
hope  to  those  who  saw  it  tliat  the  inventor  would  succeed  in  his  object.  The  public  trial  at 
Turin,  in  1853,  in  the  presence  of  manufacturers,  was  not  so  successful  as  to  remove  all 
doubts  as  to  the  merits  of  the  novel  apparatus.  In  the  following  year  it  was  submitted  to 
the  judgment  of  the  Academy  of  Sciences  at  Paris,  who  appointed  a  committee  to  examine 
it,  ))Ut  it  is  believed  that  no  report  was  ever  made.  In  1855,  a  model  of  the  loom  had  a 
place  at  the  Universal  Exhibition  at  Paris,  but  the  lateness  of  its  arrival  there  prevented  any 
official  report  being  made  in  reference  to  its  merits.  Since  then,  M.  Bonelli  has  devoted 
much  time  and  attention  in  endeavoring  to  remedy  its  defects  and  to  perfect  its  working, 
so  as  to  render  it  capable  of  holding  its  j)lace  in  the  factory.  This  M.  Bonelli  believes  he 
has  at  la.st  accomplished,  and  he  has  brought  over  to  this  country,  not  merely  a  model,  but 
a  loom  in  complete  working  order,  which  he  is  prepared  with  confidence  to  submit  to  the 
judgment  of  manufacturers,  as  a  machine  which,  from  its  economy  and  efficiency,  may  be 
put  in  favorable  comparison  with  the  Jacquard  loom. 

In  the  first  place,  it  mu^st  be  understood  that  the  special  object  of  M.  Bonelli's  machine 
is  to  do  away  with  the  necessity  for  the  Jacquard  cards  used  to  produce  the  pattern  at  the 
present  time,  the  source  of  delay  and  very  considerable  cost,  more  especially  in  patterns  of 
any  extent  and  variety  of  treatment.  JI.  Bonelli  uses  an  endless  band  of  paper,  of  suitable 
width,  the  surface  of  which  is  covered  with  tin  foil.     On  this  metuilizcd  surface,  the  required 


WEAVING  BY  ELECTRICITY. 


1089 


pattern  is  drawn,  or  rather  painted  with  a  brush  in  black  varnish,  rendering  the  parts  thus 
covered  non-conducting  to  a  current  of  electricity.  This  band  of  paper,  bearing  the  pat- 
tern, being  caused  to  pass  under  a  series  of  thin  metal  teeth,  each  of  which  is  in  connection 
with  a  small  electro-magnet,  it  will  readily  be  conceived  that  as  the  band  passes  under  these 
teeth  a  current  of  electricity  from  a  galvanic  l^attery  may  be  made  to  pass  through  such  of 
the  teeth  as  rest  on  the  metallized  or  conducting  portion  of  the  band,  and  from  such  teeth, 
through  the  respective  coils,  surrounding  small  bars  of  soft  iron,  thus  rendering  them  tem- 
porary magnets,  whilst  no  current  passes  through  those  connected  with  the  teeth  resting  on 
the  varnished  portions.  Thus,  at  every  shift  of  the  band,  each  electro-magnet  in  connection 
with  the  teeth  becomes  active  or  remains  inactive  according  to  the  varying  portion  of  the 
pattern  which  happens  to  be  in  contact  with  the  teeth.  In  a  movable  frame  opposite  the 
ends  of  the  electro-magnets,  which,  it  should  be  stated,  lie  in  a  horizontal  direction,  are  a 
series  of  small  rods  or  pistons,  as  M.  Bonelli  terms  them,  the  ends  of  which  are  respectively 
opposite  to  the  ends  of  the  electro-magnets.  These  pistons  are  capable  of  sliding  horizon- 
tally in  the  frame,  and  pass  through  a  plate  attached  to  the  front  of  it.  When  this  frame  is 
moved  so  that  the  ends  of  the  pistons  are  brought  into  contact  with  the  ends  of  the  electro- 
magnets, they  are  seized  by  such  of  them  as  are  in  an  active  state,  and  on  moving  the  frame 
forward,  those  are  retained  while  the  others  are  carried  back  with  it,  and,  by  means  of  a 
simple  mechanical  arrangement,  become  fixed  in  their  places ;  thus  there  is  in  front  of  the 
frame  a  plate,  with  holes,  which  are  only  open  where  the  pistons  have  been  withdrawn,  and 
this  plate,  as  will  be  readily  understood,  acts  the  part  of  the  Jacquard  card,  and  is  suitable 
for  receiving  the  steel  needles  which  govern  the  hooks  of  the  Jacquard  in  connection  with 
the  warp  threads  as  ordinarily  used. 

The  ordinary  Jacquard  cards  are  shown  in  the  following  wood-cut,  fifj.  687. 

Instead  of  this  arrangement,  which  will  be  understood  by  reference  to  the  article  Jac- 
quard, M.  Bonelli,  as  we  have  said,  instead  of  the  cards  prepares  his  design  on  metal  foil, 
in  a  resinous  ink,  which  serves  to  uiterrupt  the  current,  and  thus  effect  the  object  of  the  ma- 
chine. 


Fi(]s.  687  and  688  explain  generally  the  arrangements  by  which  the  process  is  effected. 

A, /^f.  688,  represents  the  plate  pierced  with  holes,  which  j)Iays  the  part  of  the  card. 

Each  of  the  small  pistons  or  rods  i,  forming  the  armatures  of  the  electro-magnets  r,  has  a 

small  head,  r/,  affixed  to  the  end,  exactly  opposite  the  needles  c,fi(U  687,  of  the  Jacquard, 

and  are  capable  of  passing  freely  through  the  holes  of  the  plate  a,  /f^.  688.     At  a  given 

Vol.  III.— 69 


L 


1090  WEAVING  BY  ELECTRICITY. 

moment  the  plate  is  slightly  lowered,  which  prevents  the  heads  of  the  pistons  passing,  and 
the  surface  of  the  plate  then  represents  a  plain  card.  The  pistons  are  sujjported  on  a  frame, 
//,  which  allows  them  to  move  horizontally  in  the  direction  of  their  length.  At  each 
stroke  of  the  shuttle,  the  frame,  carrying  with  it  a  plate,  a,  has,  by  means  of  the  treadle, 
a  reciprocating  motion  backward  and  forward,  and  in  its  backward  movement  presents  the 
end.s  of  the  pistons  to  one  of  the  poles  of  the  electro-magnets,  and,  by  means  of  certain 
special  contrivances,  contact  with  the  magnets  is  secured.  When  the  frame  f  f  returns 
with  the  j)late  a  toward  the  needles  of  the  Jacquard,  the  electro-magnets,  which  become 
temporarily  magnetized  by  the  electric  current,  hold  back  the  pistons,  the  heads  of  which 
pass  through  the  plate  a,  and  rest  behind  it.  On  the  other  hand,  the  electro-magnets  which 
arc  not  magnetized,  owing  to  the  course  of  the  current  being  interrupted,  permit  the  other  pis- 
tons to  be  carried  back,  their  heads  remaining  outside  the  plate  and  in  front  of  it.  At  this 
moment,  the  plate,  by  means  of  an  inclined  plane  beneath  it,  is  lowered  slightly,  thus  pre- 
venting the  heads  of  the  pistons  passing  through  the  holes,  by  the  edges  of  which  they  are 
stopped,  so  as  to  push  against  the  needles  of  the  Jacquard ;  on  the  other  hand,  the  heads 
of  the  pistons  which  have  passed  within  and  to  the  back  of  the  plate,  leave  the  correspond- 
ing holes  of  the  plate  free,  and  the  needles  of  the  Jacquard  which  are  opposite  to  them  are 
allowed  to  enter. 

The  electro-magnets  are  put  into  circuit  in  the  following  manner : — One  of  the  ends  of 
the  wire  forming  the  coil  of  each  of  the  magnets  is  joined  to  one  common  wire  in  connec- 
tion with  one  of  the  poles  of  a  galvanic  battery.  The  other  end  of  the  coil  wire  of  each 
magnet  is  attached  to  a  thin  metallic  plate,  w;,  having  a  point  at  its  lower  extremity.  All 
these  thin  metallic  plates  are  placed  side  by  side,  with  an  insulating  material  between  them, 
formed  like  the  teeth  of  a  comb,  n  n.  At  a  given  time  these  thin  plates  rest  with  their 
lower  extremities  on  the  sheet  bearing  the  design  p,  which,  in  the  form  of  an  endless  band, 
is  wrapped  round  and  hangs  upon  the  cylinder  q,  and  according  as  the  thin  metal  plate 
rests  on  a  metallized  or  on  a  non-conducting  portion  of  the  design,  the  corresponding 
electro-magnet  is  or  is  not  magnetized,  and  its  corresponding  piston  does  not  or  does  press 
against  the  needle  of  the  Jacquard.  The  wire  from  the  other  pole  of  the  battery  of  course 
communicates  with  the  band  bearing  the  design,  by  being  attached  to  a  piece  of  metal, 
which  lies  in  constant  contact  with  the  metallic  edge  of  the  band.  At  b  is  a  contact-breaker, 
which  is  put  in  motion  by  the  movement  of  the  frame.  Besides  this,  by  means  of  a  mechani- 
cal arrangement  connected  with  the  treddle,  which  raises  or  depresses  the  griff  frame,  the 
band  bearing  the  design  is  carried  forward  at  each  stroke,  and  the  rapidity  with  which  it  is 
made  to  travel  can  readily  be  regulated,  by  means  of  gearing,  at  the  will  of  the  workman. 
r.y  regulating  the  speed  of  the  band,  and  by  the  use  of  thicker  or  thinner  weft,  an  alteration 
in  the  character  of  the  woven  material  may  be  made,  whilst  the  same  design  is  produced, 
though  in  a  finer  or  coarser  material. 

Such  are  the  arrangements  by  which  the  loom  will  produce  a  damask  pattern,  or  one 
arising  from  the  use  of  two  colors,  one  in  the  warp  and  the  other  in  the  weft.  I  will  now 
shortly  explain  the  method  adopted  by  M.  Bonelli  for  producing  a  pattern  where  several 
colors  are  required. 

The  design  is  prepared  on  the  metallized  paper,  so  that  the  colored  parts  arc  represent- 
ed by  the  metallized  portion  of  the  band,  but  each  separate  color  is,  by  removing  a  very 
thin  strip  of  the  foil  at  the  margin,  insulated  from  its  neighboring  color.  Then  all  the 
pieces  of  foil  thus  insulated,  which  represent  one  color  or  shade,  are  connected  with  each 
other  by  means  of  small  strips  of  tin  foil,  which  pierce  through  the  paper  and  are  fastened 
at  the  back,  and  are  conducted  to  a  strip  of  tin  foil  which  runs  along  the  edge  of  the  band, 
tliere  being  as  many  such  strips  of  tin  foil  as  there  are  colors.  Thus  each  special  color  of 
tlie  pattern,  in  all  its  parts,  is  connected  by  a  conductor  with  its  own  separate  strip  of  tin 
foil,  and  by  bringing  the  wire  from  the  pole  of  the  battery  successively  into  contact  with 
the  several  strips,  a  current  of  electricity  may  be  made  to  pass  in  succession  through  the 
several  parts  of  the  design  on  the  band  representing  the  separate  colors  of  the  design. 
Thus,  assuming  four  colors,  1,  2,  3,  4,  there  would  be  four  strips  of  tin  foil  running  the 
length  of  the  band,  insulated  from  each  other,  each  of  which  would  be  in  connection  with 
its  own  separate  color  only.  At  any  given  moment,  the  thin  plates  of  metal  resting  on  the 
pattern  would  touch  it  in  a  line  which,  as  it  passes  over  the  width  of  the  pattern,  would  run 
through  all,  or  any  one  or  more  of  the  colors,  but  the  electric  current  would  pass  only 
through  those  plates  which  rest  on  the  one  color  represented  by  the  strip  with  which  the 
pole  of  the  battery  at  that  instant  happened  to  be  in  contact. 

The  inventor  claims  the  following  as  the  results  of  his  invention : — 

First. — The  great  facility  with  which  in  a  very  short  time,  and  with  precision,  reductions 
of  the  pattern  may  be  obtained  on  tlie  fabric  by  means  of  the  varying  velocity  with  which 
the  pattern  may  be  passed  under  tlie  teeth. 

Second. — That  without  changing  the  mounting  of  the  loom  or  the  pattern,  fabrics  thin- 
ner or  thicker  can  be  produced  by  changing  the  number  of  the  weft,  and  making  a  corre- 
sponding change  in  the  movement  of  the  pattern. 


^OAD. 


1091 


T7iird. — The  loom  and  its  mounting  remaining  unchanged,  the  design  may  be  changed 
in  a  few  minutes  by  the  substitution  of  another  metallized  paper  having  a  difl'erent  pattern. 

Fourth. — The  power  of  getting  rid  of  any  part  of  the  design  if  required,  and  of  modi- 
fying the  pattern. 

WIRE  ROPE.  The  mianufacture  of  ropes  made  of  wire,  has,  of  late  years,  become  a 
most  important  one.  \ot  only  are  ropes  of  this  description  now  employed  in  the  most 
extensive  coal  mines  of  this  country,  and  for  winding  generally,  but  they  are  used  for  much 
of  the  standing  rigging  of  ships,  and  for  numerous  ordinary  purposes.  Perhaps  the  most 
important  application  of  wire  rope  has  been,  however,  in  the  construction  of  the  electric 
cables.     See  Electro-telegraphy. 

The  following  Tables  show  the  relative  values  of  ropes  of  hemp,  iron,  and  steel. 

Table  I. 
Hound  Wire  Ropes,  for  inclined playies,  mines,  collieries,  ships^  standing  rigging,  d:c. 


1             Hemp. 

1                        I  EON.                        1 

Steel. 

E<JCITALE>-T   StBEXGTH. 

Circum-        lbs.  weight 

Ciream- 

lbs.  weight     1 

Circpm- 

lbs.  weight 

Working 

Breaking 

ference.        per  (athom. 

ference. 

per  fathom. 

ference. 

per  iathom. 

lead. 

•train. 

Cwts, 

Tona. 

2f 

2 

1            1 

1 

. 

6 

2 

1            1* 

1* 

1 

1 

9 

3 

3i 

4 

1            1* 

2 

- 

12 

4 

H 

2* 

u 

H 

15 

5 

4i 

5 

U 

3 

13 

6 

2 

8* 

1* 

2 

21 

7 

5J 

7 

2i 

4 

li 

2* 

24 

8 

2i 

4J 

27 

9 

6 

9 

2} 

5 

ll 

3 

80 

10 

2* 

5J 

. 

S3 

11 

6* 

10 

2i 

6 

2 

3* 

86 

12 

24 

6* 

2J 

4 

89 

13 

T 

12 

24 

7 

2J 

41 

42 

14 

!          3 

71 

45 

15 

7i 

14 

3| 

8           1 

2i 

5 

43 

16 

SJ 

Si 

51 

17 

8 

16 

sf 

9 

2* 

51 

54 

IS 

3i 

10    • 

2* 

6 

60 

20 

St 

18 

8f 

11 

2t 

61 

66 

22 

H 

12            1 

72 

24 

n 

22 

3i 

13 

3} 

8 

73 

26 

10 

26 

4 

14 

S4 

28 

4i 

15 

3| 

9 

90 

80 

11 

80 

4J 

16 

-        - 

96 

82 

4* 

13 

3J                 10 

103 

86 

12 

84 

4* 

20 

8t          1        12 

120 

40 

Bound  rope  in  pit  sliafts  must  be  worked  to  the  same  load  as  flat  ropes. 

Table  II. 
Flat  Wire  Ropes,  for  pits,  hoists,  <kc.,  d:c. 


Hemp. 

Iron.                  \ 

Steel. 

EQirrvALENT  Steekcth,  I 

Size  in 

Iba.  weight 

Size  in 

Iba.  weight 

Siic  in 

lbs.  weight 

Working 

Breaking 

inches. 

per  fathom. 

inchei. 

per  fathom.     | 

inchea. 

per  (iitboni. 

loaj. 

(train. 

1 

1 

CwU. 

Tona. 

4     X  11 

20 

21  X  1 

11      1 

. 

. 

44 

20 

5     X  11 

24 

21  X 

18       : 

. 

. 

53 

23 

51  X  U 

26        1 

21  X  f 

15        [ 

. 

. 

60 

27 

51  X  U 

23        1 

8     X 

16          1 

2     X  1 

10 

U 

23 

6     X  li 

80 

81  X 

13 

21  X  1 

11 

72 

82 

7     X  li            86         1 

31  X 

20          , 

12 

80 

86 

81  X  21           40 

31  xH/i. 

22 

21  X  1 

13 

93 

40 

SI  X  21  t        45        1 

4     X 

25 

21  X  1 

15 

'        110 

45 

9     X  21  1        50 

41  X  I 

23 

8    X 

16 

112 

60 

91  X  21           55 

41  X 

82          1 

81  X 

13 

20          1 

123 

56 

10     X  2i           60        1 

4i  X 

84         1 

8*  X 

136 

60 

WOAD  (  Voiiede,  Pa-itcl,  Fr. ;  Waid,  Germ. ;  Giialdo,  It.  Isatis  tinctoria,  Linn.)  is  al- 
most the  only  plant  growing  in  the  temperate  zone  which  is  known  to  produce  indigo. 
It  is  an  herb.iceous,  biennial  plant,  l)clonging  to  the  natural  order  crucifertc,  and  bears  yel- 
low flowers  and  large  flattened  seed  vcs;>cls,  wliich  are  often  streaked  with  purple.  The  leaves, 
which  are  the  only  part  of  the  plant  employed  iti  dyeing,  are  large,  smooth,  ami  glaucous, 
like  cabbage  leaves,  but  exhil»it  no  external  imlication  of  the  presence  of  any  blue  coloring 
matter,  which  indeed,  according  to  modern  researches,  is  not  contained  in  them  ready  fonn- 
ed.  The  plant  called  by  the  Romans  glaxtmn,  with  which,  according  to  Pliny,  the  Britons 
dyed  their  skins  blue,  is  supposed  to  be  identical  with  woad.     Before  the  introduction  of 


1092  WO  AD. 

indigo  into  the  dvehouse  of  Europe,  woad  was  generally  used  for  dyeing  blue,  and  was  ex- 
tensively cultivated  in  various  districts  of  Europe,  such  as  Thuringia,  in  Germany ;  Langue- 
doc,  in  France  ;  and  Piedmont  in  Italy.  To  these  districts  its  cultivation  was  a"  source  of 
great  wealth.  Beruiii,  a  rich  woad  manufacturer  of  Toulouse,  became  surety  for  the  pay- 
ment of  the  ransom  of  his  king,  Francis  I.,  then  a  ]irisoner  of  Charles  Y.,  in  Spain.  The 
term  pays  dc  cocaif/ne,  denoting  a  land  of  great  wealth  and  fertility,  is  indeed  supposed  to 
be  derived  from  the  circumstance  that  the  woad  balls,  called  in  French  cocaiyncs^  were 
manufactured  chiefly  in  Languedoc. 

The  woad  leaves  were  not  employed  by  the  dyer  in  their  crude  state,  but  were  previous- 
ly subjected  to  a  process  of  fermentation,  for  the  pur])ose  of  eliminating  the  coloring  matter. 
The  seed  having  been  sown  in  winter,  or  early  spring,  the  plants  were  allowed  to  grow 
until  the  leaves  were  about  a  span  long,  and  had  assumed  the  rich  glaucous  appearance 
indicative  of  maturity,  when  they  were  stripped  or  cut  off.  The  cropping  was  repeated 
several  times,  at  intervals  of  five  or  six  weeks,  until  the  approach  of  winter  put  a  stop  to 
the  growth  of  the  [dant.  The  leaves  sent  up  in  the  succeeding  spring  yielded  only  an 
inferior  article,  (called  in  Gernian  A'oinpsoivaid,)  and  it  was  therefore  customary  to  keep 
only  as  many  plants  until  the  Ibllowing  year  as  were  required  for  obtaining  seed,  which,  the 
plant  being  biennial,  is  only  produced  in  the  second  j-ear.  The  leaves,  after  being  gathered, 
were  slightly  dried,  and  then  ground  in  a  mill  to  a  paste.  In  Germany  it  was  usual  to  lav 
this  paste  into  a  heap  for  about  twenty-four  hours,  and  then  form  it  Ijy  hand  into  large  balls, 
which  were  first  dried  partially  in  the  sun,  on  lattice  work  or  rushes,  and  then  piled  up  in 
heaps  a  yard  high,  in  an  airy  j)lace,  l)ut  under  cover,  when  they  diminished  in  size  and  be- 
came hard.  These  balls,  when  of  good  cjuality,  exhibited,  on  being  broken,  a  light  blue  or 
sea-green  color.  They  were  usually  sold  in  this  state  to  manufacturers,  Ijy  whom  they  were 
subjected  to  a  second  process  in  order  to  render  them  fit  for  the  use  of  the  dyer.  This 
process  was  conducted  in  the  following  manner: — The  woad  balls  were  first  broken  by 
means  of  wooden  hammers,  and  the  triturated  |jaass  was  heaped  up  on  a  wooden  floor, 
sprinkled  with  water,  sometimes  with  a  little  wine,  and  allowed  to  ferment  or  putrefy.  The 
mass  became  very  hot,  and  emitted  a  strong  ammoniacal  odor,  and  much  vapor.  In  order 
to  regulate  the  process  it  was  frec|uently  turned  over  with  shovels  and  again  sprinkled  with 
water.  When  the  heat  had  subsided,  the  ma.^s,  which  had  become  dry,  was  pounded,  pass- 
ed through  sieves,  and  then  packed  in  barrels  ready  for  use.  It  had  the  appearance  of 
pigeon's  dung. 

In  France  the  paste  obtained  by  pounding  the  woad  leaves  was  taken  to  a  room  with  a 
sloping  pavement,  open  at  one  end,  laid  in  a  heap  at  the  higher  end  of  the  room,  and  al- 
lowed to  ferment  for  a  period  of  twenty  or  thirty  days.  The  mass  swelled  up  and  often 
showed  cracks  or  fissures,  which  were  always  carefully  closed  as  soon  as  they  appeared, 
whilst  a  black  juice  exuded  and  ran  away  in  gutters  constructed  for  the  purpose.  AVhen 
the  fermented  heap  had  become  moderately  dry,  it  was  ground  again  and  formed  into  cakes, 
called  in  French  coqnes,  which  were  then  fully  dried,  and  in  this  state  brought  to  market. 
In  France  and  Italy  a  second  fermentation  was  not  generally  thought  essential,  but  when 
performed  it  was  conducted  exactly  in  the  manner  just  descril)ed. 

At  the  present  day  woad  is  nowhere  employed  alone  for  the  purpose  of  dyeing  blue, 
since  it  is  found  more  economical  to  use  indigo,  and  the  cidtivation  of  the  plant  has  there- 
fore declined  considerably,  and  has  even  Ijecome  nearly  extinct  in  districts  where  it  was 
formerly  carried  on  extensively.  By  woollen  dyers,  however,  it  is  still  used,  but  only  as  a 
means  of  exciting  fermentation,  and  thus  reducing  the  indigo  blue  in  their  vats;  indeed, 
the  woad  employed  by  them  contains  little  or  no  blue  coloring  matter.     See  Indigo. 

Numerous  attempts  have  been  made  to  extract  the  blue  coloring  matter  from  woad,  in 
the  same  way  that  indigo  is  extracted  from  the  leaves  of  the  indigofera  in  the  East  Indies 
and  other  countries.  At  the  commencement  of  the  present  century,  when  the  price  of  in- 
digo on  the  continent  of  Europe  was  very  high,  a  prize  of  100,OfiO  francs  was  even  offered 
by  the  French  government  for  the  discovery  of  a  method  of  obtaining  from  the  Isatis  tinc- 
toria,  or  some  other  native  plant,  a  dyeing  material,  which,  both  in  regard  to  price  and  the 
beauty  and  solidity  of  its  color,  should  form  a  perfect  substitute  for  indigo.  The  expei  i- 
mcnts  which  were  made  in  consequence  served  to  prove  that  it  was  quite  possible  to  obtain 
genuine  indigo  from  woad  leaves,  but  that  the  process  could  never  be  carried  on  profitably, 
on  account  of  the  very  small  proportion  of  coloring  matter  contained  in  the  plant.  Nine 
parts  of  fresh  leaves  yield  only  one  part  of  the  prepared  material  or  pastel,  and  the  latter 
does  not  afford  more  than  2  per  cent,  of  its  weight  of  indigo.  According  to  Chevreul,  the 
leaves  of  the  Indif/nfrra  anil,  even  when  grown  in  the  neighboihood  of  Paris,  contain  30 
times  as  much  indigo  blue  as  those  of  the  Isatis  iitictoria,  and,  when  cultivated  in  tropical 
countries,  the  amount  is  probably  still  higher.  The  comparatively  high  price  of  land  and 
labor  would  probably  itself  prove  a  sufficient  obstacle  to  the  successful  manufacture  of 
indigo  in  most  European  countries,  even  if  the  yield  were  equal  to  what  it  is  in  the  tropics. 

In  1808  Chevreul  published  the  results  of  his  analysis  of  woad  and  pastel.  It  has  more 
recently  been  made  the  subject  of  chemical  investigation,  for  the  purpose  of  ascertaining 
the  state  in  which  indigo  blue  exists  in  plants  and  other  organisms.     See  Ixdigo. — E.  S. 


zmc. 


1093 


ZINC,  METALLURGY  OF.  RoaMing  of  Ores.— Blonde,  or  sulphide  of  zinc,  is,  pre- 
vious to  its  treatment  for  metal,  carefully  roasted  in  a  reverberator)'  furnace,  over  the  bot- 
tom of  which  it  is  spread  in  a  layer  of  about  four  inches  in  thickness.  A  strong  heat  is 
necessary  for  this  purpose,  and  during  the  operation  the  charge  is  frequently  stirred  with  a 
strong  iron  rake,  with  a  view  of  exposing  fresh  surfaces  to  the  gases  of  the  furnace.  The 
apparatus  most  commonly  employed  in  this  country  for  roasting  sulphide  of  zinc  consists 
of  a  reverberatory  furnace  about  36  feet  in  length  and  9  feet  in  width,  provided  with  a  fire- 
place of  the  usual  construction.  The  sole  or  hearth  of  this  apparatus  i.s  divided  into  three 
distinct  beds,  of  which  that  nearest  the  fire  bridge  is  4  inches  lower  than  that  which  is  next 
it,  which  is  again  4  inches  lower  than  that  nearest  the  chimney.  In  addition  to  the  heat 
derived  from  the  fireplace,  the  gases  escaping  from  the  reducing  furnaces  are  usually  intro- 
duced immediately  before  the  bridge,  and  a  considerable  economy  of  fuel  is  thcrel)y  eHected. 
When  the  furnace  has  been  sufficiently  heated  a  charge  of  12  cwt.  of  raw  blende  is  intro- 
duced into  the  division  nearest  the  chimney  and  equally  .spread  over  the  bottom,  care  being 
taken  to  stir  it  from  time  to  time  by  means  of  an  iron  rake,  as  before  described.  After  the 
expiration  of  about  eight  hours  this  charge  is  worlvcd  on  to  the  floor  of  the  compartment 
forming  the  middle  of  the  furnace,  and  a  new  charge  is  introduced  into  the  division  next 
the  chimney.  About  eight  hours  after  this  charging  the  ore  on  the  middle  bed  is  worked 
on  to  the  first,  whilst  that  on  the  hearth  next  the  chimney  is  equally  spread  on  the  middle 
one  and  a  new  charge  introduced  into  the  division  next  the  stack.  After  the  expiration  of 
another  period  of  eig'it  hours  the  charge  on  the  first  hearth  is  drawn,  the  ore  on  the 
middle  and  third  hearths  moved  forward,  and  a  fourth  charge  introduced  as  before.  In 
this  way  the  operation  is  continuous,  and  each  furnace  will  effect  the  calcination  of  about  36 
cwt.  of  ordinary  blende  in  the  course  of  24  hours. 

Calamine,  or  silicate  of  zinc,  is  usually  prepared  for  smelting  by  calcination  in  a  furnace 
resembling  an  ordinary  lime  kiln,  the  heat  being  often  supplied  by  means  of  four  fireplaces 
arranged  externally,  and  so  placed  that  the  heated  gases  may  be  drawn  into  it,  and  regularly 
distributed  through  the  interstices  existing  between  the  masses  of  ore.  Calamine  subjected 
to  this  treatment  commonly  loses  about  one-third  of  its  weight,  and  is  at  the  same  time  ren- 
dered so  friable  as  easily  to  admit  of  being  reduced  to  fine  powder  by  an  ordinary  edge-mill. 

Reductiox. 

Beh/ian  process. — When  this  method  of  treating  zinc  ore  is  employed,  the  furnace  rep- 
resented in  fi(/.  6S9  is  commonly  used. 


089 


GOO 


Fir/.  689  represents,  on  the  left  hand,  a  front  elevation  of  the  furnace,  and  on  the  right  a 
sectional  elevation  through  the  ashpit  and  fireplace,  f  is  the  fireplace,  whilst  a  is  the 
cavity  into  which  are  introduced  the  retorts  destined  for  the  distillation  of  the  metal. 


lO'M 


zmo. 


The  products  of  combustion  escape  by  the  openings  g  into  a  flue,  by  which  they  are 
conducted  into  the  calciner  for  the  purpose  of  economizing  the  waste  heat.  These  furnaces 
are  either  arranged  in  couples,  back  to  baclf,  or  in  groups  of  four,  for  the  purpose  of  ren- 
dering thft  structure  more  solid,  and  economizing  heat.  In  the  arched  chamber  a  are  placed 
48  cylindrical  retorts,  8  feet  6  inches  in  length  from  b  to  d,  and  *?  inches  internal  diameter. 
These  are  made  of  refractory  fire  clay,  well  baked  and  supported  behind  by  ledges  of 
masonry,  «,  6,  fg.  690,  whilst  in  front,  at  c  d,  they  rest  on  tire-clay  saddles  let  into  an  iron 
framing.  Short  conical  fire-clay  pipes,  10  inches  in  length  from  (Z  to  c,  are  fixed  in  the 
mouths  of  these  retorts  by  means  of  moistened  clay,  and  project  for  a  short  distance  be- 
yond the  mouth  of  the  furnace.  To  these  are  adapted  thin  wrought-iron  cones  18  inches 
in  length  from  c  to/,  tapering  off  at  the  smaller  extremity  to  an  orifice  of  about  three  quar- 
ters of  an  inch  in  diameter.  The  inclined  position  of  the  retorts,  the  method  of  adjusting 
the  pipes,  and  the  general  arrangement  of  the  apparatus  are  shown  in///.  690,  in  which  r,  r, 
J-,  ?•,  represent  the  nozzles  of  thin  wrought  iron.  When  a  new  furnace  is  first  lighted  the 
retorts  are  introduced  without  being  jireviously  baked,  but  care  must  be  taken  that  they 
be  perfectly  dry  and  seasoned,  and  for  this  reason  it  is  necessary  to  keep  a  large  stock  con- 
stantly on  hand,  in  a  store  house  artificially  heated  by  means  of  "some  of  the  flues  of  the  es- 
tablishment. The  heat  is  gradually  increased  during  three  or  four  days,  at  the  end  of 
which  period  charges  of  ore  are  introduced,  the  clay  cones  are  luted  in  their  places,  and 
the  furnace  is  brought  into  full  working  order.  The  charge  of  a  furnace  consists  of  1,680 
lbs.  of  roasted  blende  or  calcined  calamine,  and  840  lbs.  of  coal  dust.  The  ore  and  coal 
dust,  after  deing  finally  divided  and  intimately  mixed,  is  slightly  damped,  and  subsequently 
introduced  into  the  retorts  by  means  of  a  semi-cylindrical  scoop,  by  the  aid  of  which  an 
experienced  workman  will  eftect  the  charging  without  spilling  the  smallest  quantity  of  the 
mixture. 

In  this  country  the  retorts  in  the  lower  tier  are  usually  not  charged,  as  they  are  ex- 
tremely lialjle  to  be  broken,  and  are  therefore  only  employed  to  modei-ate  the  heat  of  the 
furnace.  On  the  Continent,  however,  the  fireplace  is  frecj[uently  covered  by  a  hollow  arch, 
and  in  that  case  every  retort  requires  a  charge  of  ore. 

The  mixture  introduced  into  the  retorts  varies,  to  a  certain  extent,  with  their  position 
in  the  furnace,  for  in  spite  of  every  precaution  to  prevent  inequality  of  temperature,  it  is 
found  impossible  to  heat  the  whole  of  them  alike,  and  those  next  the  fire,  therefore,  from 
being  the  most  strongly  heated,  are  liable  to  work  off  first.  As  soon  as  the  retorts  have 
been  charged  the  clay  cones  are  luted  into  their  places,  and  carbonic  oxide  gas,  which  burns 
with  a  blue  flame  at  the  mouth  of  the  cones,  quickly  makes  its  appearance.  The  quantity 
of  this  gas  gradually  diminishes,  and  as  soon  as  the  flame  assumes  a  greenish-white  hue, 
and  white  fumes  are  observed  to  be  evolved,  the  sheet-iron  cones  are  put  on,  and  the  fur- 
nace at  once  enters  into  steady  action.  From  time  to  time,  as  the  iron  cones  become  choked 
with  oxide,  they  are  taken  off  and  gently  tapped  against  some  hard  substance,  so  as  to  re- 
move it,  and  then  replaced.  The  oxide  thus  collected  is  added  to  the  mixture  prepared  for 
the  next  charge.  After  the  expiration  of  about  six  hours  from  the  time  of  charging  the 
wrought-iron  tubes  are  successively  removed,  and  the  metallic  zinc  scraped  from  the  clay 
pipes  into  an  iron  ladle.  This,  when  full,  is  skimmed,  and  the  oxide  added  to  that  obtained 
from  the  nozzles,  whilst  the  pure  metal  is  cast  into  ingots,  weighing  about  28  lbs.  each.  At 
the  expiration  of  twelve  hours  from  the  time  of  charging  the  zinc  is  again  tapped,  and  the 
residue  remaining  in  the  retorts  withdrawn.  The  rctoits  are  immediately  recharged,  and  the 
operation  of  reduction  is  conducted  as  above  described. 

The  residues  obtained  from  the  retorts,  after  the  first  working,  are  passed  through  a 
crushing  mill,  mixed  with  a  further  quantity  of  small  coal,  and  again  treated  for  the  metal 
they  contain.  The  earthen  adapters  or  cones,  when  unfit  for  further  service,  are  crushed 
and  treated  as  zinc  ores. 

In  order  to  work  these  furnaces  with  economy,  it  is  of  the  greatest  importance  that 
they  should  be  constantly  supplied  with  a  full  number  of  retorts,  since  the  amount  of  fuel 
consumed,  and  the  general  expenses  incurred  for  each  furnace,  will  be  the  same  if  the  ap- 
paratus has  its  full  complement  of  retorts,  or  if  one-half  of  them  are  broken  and  conse- 
quently disabled. 

It  is  therefore  necessary,  in  all  zinc-smelting  establishments,  to  keep  a  large  stock  of  well- 
seasoned  retorts,  which,  before  being  introduced  into  the  furnace,  to  make  good  any  deficiency 
cau.sed  by  breakage,  are  heated  to  full  redness  in  a  kiln  provided  for  that  purpose.  The 
Belgian  process  of  zinc  smelting  is  that  M-hich  is  at  present  most  employed  in  this  country. 
The  principal  localities  in  which  zinc  ores  are  treated  are  Swansea,  Wigan,  Llannelly,  and 
Wrexham. 

Silesian  procoxx. — In  the  zinc  works  of  Silesia  the  furnaces  employed  differ  considerably 
from  those  used  in  the  Belgian  process. 

Fifi.  001  represents  an  elevation,  and  ///.  692  a  vertical  section  of  the  Silesian  furnace. 
The  distillation  is  effected  in  a  sort  of  muffle  of  baked  clay,  m,  fig.  692,  and  figs.  093, 
G94,  about  3  feet  3  inches  in  length,  and  20  inches  in  height.     The  front  of  this'  imiffle  is 


ZINO. 


1095 


pierced  with  two  apertures.  The  lower  opening,  d,  serves  to  remove  the  residues  remaining 
in  the  retorts  after  each  operation,  and  is  closed  during  the  process  of  distillation  l)y  a  small 
door  of  baked  clay,  firmly  luted  in  its  place.  In  the  upper  opening  is  introduced  a  hollow 
cliy  ar.n,  bent  at  right  angles,  «,  6,  c,  and  which  remains  open  at  c.  An  opening  at  b  per- 
mits of  charging  the  retort  by  means  of  a  proper  scoop,  and  this,  during  the  operation,  is 
closed  by  a  luted  clay  plug.  From  six  to  ten  of  these  muffles  or  retorts  are  arranged  in 
rows,  on  either  side  of  a  furnace  provided  with  suitable  apeiturcs  for  their  introduction. 
They  are  securely  luted  in  their  places,  and  the  openings  closed  by  sheet-iron  doors,  by 
which  the  too  rapid  cooling  of  the  pipe  a,  6,  c  is  prevented.  The  fuel  employed  is  coal, 
which  is  burnt  on  the  grate  G,  situated  in  the  centre  of  the  furnace.  The  retorts  are  charged 
with  a  mixture  of  calamine  and  small  coal,  or  more  frequently  coke  dust,  since,  when  coal  i3 
employed,  the  products  of  distillation  are  found  to  be  liable  "to  choke  the  pipe  «,  h,  c.  The 
zinc  escapes  by  the  opening  c  of  the  adapter,  and  is  received  into  the  cavities  o  of  the  furnace. 

The  furnace  shown  in  'ficjs.  (595,  690,  097,  is  for  remelting  the  metallic  zinc.  Fi().  096 
is  a  front  view;  fig.  695  is  a  transverse  section,  fig.  09*7  a  view  from  al)ove;  a  is  the  fire- 
door  ;  b  tlio  grate ;  c  the  fire  bridge ;  d  the  tluc ;  c  the  chimney ;  /,  /,  /  east-iron  melt- 
ing pots,  wliich  contain  each  about  10  cwt.  of  metal.  The  heat  is  moderated  by  the  suc- 
cessive addition  of  pieces  of  cold  zinc.  The  inside  of  the  pots  is  sometimes  coated  with 
loam,  to  prevent  the  iron  lacing  attacked  by  the  zinc. 

In  some  establishments,  and  particularly 
those  at  Stolberg  in  Prussia,  the  retorts  have 
the  form  i),  represented  in  fig.  098.  C  is  an 
adapter  also  of  fire  clay ;  b  a  cone  of  wrought 
iron,  and  a  a  small  vessel  of  the  same  ma- 
terial for  tlie  collection  of  the  oxide,  and  fur- 
nislied  in  the  bottom  with  an  aperture  for  the 
escape  of  the  gases  generated. 


698 


1096 


ZINC. 


These  are  arranged  on  either  side  of  a  grate  as  represented,  fig.  G99,  an  internal  open- 
ing serving  for  two  retorts,  and  of  which  there  are  usually  twelve  in  each  furnace,  e  is 
the  fire  door ;  f  grate ;  G  chamber  in  masonry  of  furnace ;  u  diaphragm  of  fire  brick  sup- 
porting adapter,  in  the  depressed  part  of  which  the  metallic  zinc  is  collected  and  subse- 
quently removed  by  a  scraper,  as  in  the  case  of  the  cone  of  the  Belgian  retort.  The  wrought- 
iron  vessel  a  is  supported  by  a  chain  or  wire  J. 

Fig.  VOO  represents  a  longitudinal  elevation  of  the  roasting  furnace  employed. 


The  general  consumption  of  Spelter  throughout  the  world  is  about  67,000  tons  per 
annum,  of  which  about  44,000  tons  are  made  to  take  the  shape  of  rolled  sheets,  and  these 
are  estimated  to  be  applied  as  follows,  each  quantity  being  somewhat  below  the  truth: — 

Tons. 
Roofing  and  architectural  purposes       ....         23,000 

.   Ship  sheathing 3,500 

Lining  packing  cases 2,500 

Domestic  utensils 12,000 

Ornaments 1,500 

Miscellaneous 1,500 


44,000 
Fifteen  years  ago  the  quantity  used  for  roofing  did  not  exceed  6,000  tons;  none  was 
employed  for  ship  sheathing  or  lining  packing  cases,  and  stamped  ornaments  in  zinc  date 
only  from  1852. 

From  the  low  temperature  at  which  zinc  fuses,  and  from  the  sharpness  of  impressions 
possessed  by  castings  in  this  metal,  it  is  much  employed  on  the  Continent  for  the  production 
of  statues  and  statuettes.  The  uses  of  this  metal  in  the  preparation  of  alloys  have  already 
been  noticed  under  the  head  of  alloys.  It  is  also  employed  like  tin  for  coating  iron,  pro- 
ducing what  is  known  as  galvanized  iron.  The  disinfectant  liquor  of  Sir  W.  Burnett  is 
chloride  of  zinc,  and  the  oxide  of  this  met.al  is  much  employed  as  a  pigment  in  place  of 
white  lead.     Zinc  or  Spelter  imports  in  1858: — 

Crude  in  cakes.  Tons. 

Denmark  ......         271' 

Prussia 9,034 

Hamburg 8,413 

Holland 1,259  f 

Belgium 240 

Other  Parts 302  J 


Computed  real 

value. 

£470,195. 


Eolled,  but  not  otherwise 
manufactured. 
Denmark 
Prussia   - 
Belgium 
Other  Parts     - 


19,519 

Tods. 

47  T 

304  1 

3,818  f 

37j 

4,206 


Computed  real 
v.iluo. 

£128,738. 


THE    EISTD. 


ULSa   U BR ARY. 


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